GB/T 15623.1-2003 Hydraulic transmission electrically modulated hydraulic control valves Part 1: Test methods for four-way directional flow control valves
Some standard content:
GB/T15623.1—2003
This part is compiled by modifying the international standard IS010770-1:1998 "Hydraulic drive electric modulation wave pressure control valve Part 1: Test method for four-way directional flow control valve", and is a revision of GB/T15623--1995 "Test method for electro-hydraulic servo valve". This part and GB/T15623.2—2003 abolish and replace GB/T15623-1995. GB/T15623, under the general title "Hydraulic drive electric modulation hydraulic control valve", consists of the following parts: Part 1: Test method for four-way directional flow control valve; -- Part 2: Test method for three-way directional flow control valve; -- Part 3: Test method for pressure control valve. This part has the following technical differences from ISO10770-1:1998: In "2 Normative References", this part replaces the international standards cited in ISO10770-11998 with the corresponding national standards;
——In "Figure 16a)", "rise time" replaces "response time"; - In ISO10770-1:1998, A and B oil ports are called "control oil ports". In order to conform to the habits of my country's hydraulic industry and to distinguish them from the concepts of "pilot control oil ports and external control oil ports", this part changes them to "working oil ports". ~ - "Filtration" in Table 2 is changed to "oil contamination level", and the description column is changed to "oil contamination level should be in accordance with the use regulations of the component manufacturer, and the expression method should be in accordance with GB/T14039".
一-In the test steps 8.1.2.2.3 and 8.1.2.3.3 of IS010770-11998, *maintain the oil supply pressure for at least 30s\This part changes it to \maintain the oil supply pressure for at least 5min". -The reference to Appendix C of ISO10770-1:1998 is deleted. This part makes the following modifications to GB/T15623-1995: Part I specifies the test method for four-way directional flow control valves. Part I is more comprehensive and has a wider scope of application than the previous version. It not only includes the test method for electro-hydraulic servo valves, but also covers the test methods for electric Test methods for hydraulic proportional directional valves and electro-hydraulic proportional flow valves. - The name of the standard is changed to be consistent with the name of the adopted international standard. Appendix A of this part is a normative appendix, and Appendix B is an informative appendix. This part is proposed by the China Machinery Industry Federation. This part is under the jurisdiction of the National Hydraulic and Pneumatic Standardization Technical Committee (SACS/TC3). Drafting units of this part: National Key Laboratory of Fluid Transmission and Control, Zhejiang University, Beijing Institute of Automation of Mechanical Industry. The main drafters of this part: Wu Genmao, Qiu Minxiu, Shang Zengwen, Liu Xinde, Zhao Manlin. The previous versions of the standards replaced by this part are: -GB/T 15623-1995.
GB/T15623.1—2003
In a hydraulic transmission system, power is transmitted to one or more loads through an electrically modulated hydraulic control valve by means of a pressurized fluid from a hydraulic power source.
This type of control valve is a component that receives an electrical control signal and obtains hydraulic power from a power source, and then controls the direction and flow of the fluid flowing to the load according to the magnitude and polarity of the input electrical signal. In order to successfully apply electrically modulated hydraulic control valves, it is necessary to understand many of the static and dynamic characteristics of this type of valve and its Test methods. IV
1 Scope
Hydraulic transmission electrically modulated hydraulic control valves
Part 1: Test methods for four-way directional flow control valves GB/T15623.1--2003
This part specifies the methods for product acceptance and type (or identification) tests for electrically modulated hydraulic four-way directional flow control valves. 2 Normative references
The clauses in the following documents become the clauses of this part through reference to this part of GB/T15623. For all dated references, all subsequent amendments (excluding The latest versions of the referenced documents (including errata) or revisions are not applicable to this part. However, parties to an agreement based on this part are encouraged to investigate whether the latest versions of these documents can be used. For any undated referenced documents, the latest versions apply to this part.
GB/T786.1 Hydraulic and pneumatic graphic symbols (eqvISO1219-1:1991) GB/T3141 Industrial liquid lubricant ISO viscosity classification (eqvISO3448:1992). GB/T4728 (all parts) Graphic symbols for electrical schematics (idtIEC6 17) GB/T7631.2 Classification of lubricants and related products (Class I) Part 2: Group H (Hydraulic systems) (eqvISO6743-4:1982)
GB/T14039
Hydraulic transmission oil solid particle contamination level code (ISO4406:1999, MOD) GB/T17446 Fluid transmission system and component terminology (idtISO5598:1985) 3 Terms and definitions
The terms and definitions established in GB/T17446 and the following terms and definitions apply to this part. 3.1
Electrically modulated hydraulic flow control valves Valves that provide proportional flow control in response to a continuously changing electrical input signal. 4 Symbols and units
The symbols and units of the characteristic parameters related to this part are listed in Table 1. Table 1 Characteristic parameter symbols and units
Characteristic parameter
Coil impedance
Coil inductance
Coil resistance
Insulation resistance
Flutter amplitude
Flutter frequency
Input signal
Rated signal
IN or UN
%Percentage of maximum input signal
GB/T 15623.1—2003
Characteristic parameters
Output flow
Rated flow
Flow gain
Internal leakage
Supply pressure
Return pressure
Load pressure
Valve pressure drop
Rated valve pressure drop
Pressure gain
Amplitude ratio
Phase shift
Note: 1bar=105N/m2-0.1MPa
Standard test conditions
Table 1 (continued)
K=(8g/81 or 8q/U)
py = p- PA or pA PT
Sv=(8pA/81 or 8pA/8U)
1/min/input signal unit
%Percentage of maximum input signal
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)/input signal unit
%Percentage of maximum input signal
degrees(°)
Unless otherwise specified, the standard test conditions given in Table 2 apply to the tests specified in this standard. Table 2 Standard test conditions
Ambient temperature
Oil contamination level
Hydraulic oil type
Hydraulic oil temperature
Hydraulic oil viscosity grade
Oil supply pressure
Oil return pressure
(20±5)℃
Oil contamination level should be in accordance with the component manufacturer's usage regulations, and the expression method should be in accordance with GB/T14039. Mineral-based hydraulic oil sold on the market, that is, L-HL hydraulic oil specified in GB/T7631.2 or other hydraulic oil suitable for valve operation
At the valve inlet (40±6)℃
N 32, according to GB/T 3141
According to the corresponding test requirements, the allowable error is ±2.5% as recommended by the manufacturer
Note: When using other alternative hydraulic oils, the type and viscosity grade of the oil should be specified. 6 Test equipment
6.1 Overview
A test equipment that complies with the provisions of 6.2 and 6.3 and can meet the allowable error limits specified in Appendix A should be provided. Appendix B provides guidance on the implementation of the test.
GB/T 15623.1--2003
Note 1: Figures 1, 2 and 3 are typical test circuits. These circuits do not include all the safety devices that must be set up to prevent accidents due to component failure. Other test circuits that can achieve the same purpose may be used, but safety measures for test personnel and test equipment must be considered. Note 2: The graphic symbols used in Figures 1, 2 and 3 should comply with the provisions of GB/T786.1 and GB/T4728. 6.2 Static test
Figure 1 shows a typical static test circuit. The test device using this circuit allows the following characteristic curves to be recorded by point-by-point or continuous drawing method:
Flow-input signal characteristic curve;
Pressure-input signal characteristic curve;
Flow-valve pressure drop characteristic curve;
Flow-load pressure characteristic curve;
e) Flow-temperature characteristic curve.
6.3 Dynamic test
Figure 2 shows a typical dynamic test circuit. This circuit uses part of the circuit in Figure 1. The test device using this circuit can perform the following tests:
a) Frequency response test;
b) Step response test.
7 Electrical Tests
7.1 General
Before proceeding with the subsequent tests, all valves without integrated circuits shall be subjected to the tests specified in 7.2 to 7.4, as appropriate. 7.2 Coil Resistance
This test shall be conducted on the coil at the specified ambient temperature. The resistance between the ends of the valve coil shall be measured using an electronic measuring instrument with a measurement accuracy better than ±2% of the measured value.
Note: It is not necessary to supply pressurized oil to the valve under test when measuring the coil resistance. 7.3 Coil Inductance
7.3.1 Measure the total coil inductance of the valve operating under the standard test conditions specified in Table 2 (for coil series with four-lead, dual-coil construction).
Note: The apparent inductance measured in this test will vary with the frequency and amplitude of the signal due to the influence of the back EMF (electrical motion force) generated by the moving armature. The test results can be used to select an appropriate drive amplifier. 7.3.1.1 Connect a suitable oscillator to drive the valve coil, which needs to be connected in series with a precision non-inductive resistor, see Figure 3a).
Adjust the oscillator frequency f to 50 Hz or 60 Hz to distinguish it from the power supply frequency of the test equipment. 7.3.1.3 Adjust the input current of the valve so that its peak value is equal to the rated current of the valve. 7.3.1.4 Use an oscillator that can provide undistorted current to the valve. 7.3.1.5 Use an oscilloscope to monitor the voltage waveform of the resistor R and check whether the waveform is a sine wave. 7. 3. 1. 6
Measure the peak values of the AC voltages UR, Ur and Uv. Draw the curve shown in Figure 3b) to represent the vector relationship between the voltages. 7.3.1.7
7.3.1.8
Determine the coil impedance according to the following formula:
Where:
Z—impedance, in ohms (0).
（1）
GB/T15623.1—2003
Where:
L—apparent inductance, in henry (H).
2 yuan f ×Ug
7.3.2Another optional test method: Use the step response at full current to obtain the coil time constant tc, and calculate the inductance using the following formula: L =R. × t (as shown in Figure 4)
7.4 Insulation resistance
Apply a DC voltage of 500V between the coil terminals and the valve body for 15s. While applying the voltage, measure the insulation resistance using a corresponding insulation tester. The current reading on the tester corresponds to the resistance and the insulation resistance is calculated in ohms (Q) by the following formula: R: - 500 V
where the measured current I is expressed in amperes (A). This resistance is generally in excess of 100 MQ. In addition, for a four-lead dual-coil construction, the resistance between the coils can also be determined. If the internal electrical components are in contact with the fluid (e.g., wet coils), the valve should be filled with hydraulic fluid before this test. 8 Performance Tests
When performing all of the following tests, the amplifier specified by the valve manufacturer (when an amplifier is specified) should be included in the test system. If an external pulse width modulated amplifier is used, the modulation frequency should be recorded. In all cases, the amplifier supply voltage should be recorded. Note: All performance tests should be performed on both the valve and the amplifier. The input signal is applied to the amplifier, not directly to the valve. 8.1 Static Tests
8.1.1 General
When performing these tests, care should be taken to exclude dynamic effects. Before any other tests are carried out, the test a) should be carried out first. a) Withstand pressure test, according to 8.1.2; b) Internal leakage test, according to 8.1.3; Under constant valve pressure drop, output flow-input signal characteristic test, according to 8.1.4 and 8.1.5, to determine: c) 1) Rated flow; 2) Flow gain; 3) Flow linearity; 4) Flow hysteresis; 5) Flow symmetry; 6) Flow polarity; 7) Valve core cover condition; 8) Threshold value.
8) Commercial
Throttling regulation characteristic test, according to 8.1.6;
Output flow-load pressure difference characteristic test, according to 8.1.7; output flow-valve pressure drop characteristic test, according to 8.1.8; limit power characteristic test, according to 8.1.9;
Output flow or valve core position-oil temperature characteristic test, according to 8.1.10; pressure difference-oil temperature characteristic test, according to 8.1.11; pressure gain-input signal characteristic test, according to 8.1.12; k)
Pressure zero drift, according to 8.1.13;
Fault protection function test, according to 8.1.14. 8.1.2 Pressure resistance test
8.1.2.1 Overview
GB/T 15623.1--2003
The pressure test shall be conducted before other tests on the valve to verify the pressure resistance of the valve. A simplified high-pressure test device may be used for this test instead of the device of the test circuit shown in Figure 1. 8.1.2.2 Oil supply pressure test
During the test, the pressure resistance pressure is applied to the pressure oil port and the working oil port of the valve, and the return oil port is opened at the same time. This test shall be carried out as follows. 8.1.2.2.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.2.2.2 Setting
Adjust the oil supply pressure of the valve to 1.3 times the rated oil supply pressure or 35MPa (350bar), whichever is lower. 8.1.2.2.3 Test steps
Maintain the oil supply pressure for at least 5 minutes.
In the first half of the test, input the maximum positive input signal; in the second half of the test, input the maximum negative input signal. During the test, check the valve for external leakage and signs of permanent deformation. 8.1.2.3 Oil return port pressure test
During the test, the pressure resistance pressure is applied to the pressure oil port, working oil port and oil return port of the valve. The test should be carried out as follows. 8.1.2.3.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves c, e and h at the same time, and close all other valves. 8.1.2.3.2 Set
Adjust the oil supply pressure of the valve to 1.3 times the specified maximum oil return port pressure. 8.1.2.3.3 Test steps
Maintain this pressure for at least 5 minutes.
In the first half of the test, input the maximum positive input signal, and in the second half of the test, input the maximum negative input signal. No external leakage and permanent deformation should occur during the test. 8.1.3 Internal leakage test (working oil port closed) 8.1.3.1 General
Before the test, make the necessary mechanical/electrical adjustments, such as zeroing the valve. Then carry out the test as follows to determine the total internal leakage including all pilot control flows. 8.1.3.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, with valve g open and all other valves closed. 8.1.3.3 Set
Adjust the supply pressure of the valve to 10 MPa (100 bar) above the return pressure and the appropriate pilot pressure. 8.1.3.4 Test procedure
Carry out the test as follows:
a) Before the leakage test, run the valve several times quickly over the entire input signal range. b) Record the leakage at port T and port Y over the maximum positive and negative input signal range (see Figure 5). If necessary, repeat these tests with the pressure increased to the maximum supply pressure of the valve under test. Note: For some special valve cores, it is necessary to measure the pilot flow and the leakage between the oil ports separately, see 8.1.6. 8.1.4 Output flow-input signal characteristics under constant valve pressure drop (open working oil port) 8.1.4.1 Overview
This test should be carried out to obtain the output flow-input signal characteristic curve, and thus obtain the steady-state characteristics of the valve. 8.1.4.2 Test circuit
8.1.4.2.1 For multi-stage valves with internal pilot oil supply, a circuit configuration with appropriate modifications can be used, such as any of the following 5
GB/T15623.1—2003
Method:
a) Insert a pressure compensator between the valve and the test oil block. b) Use the loading valve shown in Figure 1 to load the test valve. The valve can operate in open or closed loop conditions to maintain a constant pressure drop across the valve.
8.1.4.2.2 Adjust the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, g, j, and close all other valves. 8.1.4.3 Setting
8.1.4.3.1 Depending on the specific situation, the total pressure drop of the valve is set at 1MPa (10bar), 7MPa (70bar) or 1/3 of the maximum oil supply pressure. 8.1.4.3.2 For multi-stage valves with independent pilot oil supply, adjust the pilot oil supply pressure to 10MPa (100bar). 8.1.4.3.3 For multistage valves with internal pilot oil supply, adjust the oil supply pressure to 10 MPa (100 bar), unless otherwise specified by the manufacturer. 8.1.4.4 Test procedure
Perform the test as follows:
Cycle the input signal several times.
Use continuous plotting/recording mode and establish an appropriate coordinate system to record the input signal on the X axis and the output flow on the Y axis. b)
Adjust the automatic signal generator to produce an input signal with a triangular waveform that can achieve the maximum positive and negative amplitude. Make the input signal change continuously and periodically to ensure that the recording pen moves freely at a certain speed, that is, at this speed, the dynamic influence of the flow sensor d)
and its output signal and the recorder can be ignored. When using an XY plotter or recorder, the automatic control valve must have a certain pressure drop and ensure that the pressure drop changes within 5% during the entire signal cycle. While the signal is continuously changing in a cycle, continuously record the characteristics within a complete signal cycle (see Figure 6). According to steps a) to e) of 8.1.4.4e)
, determine the following characteristics: 1) output flow at rated signal;
2) flow gain;
3) linearity;
4) hysteresis;
dead zone characteristics (i.e. valve core covering state); 6) symmetry;
7) polarity;
8) limit power (see 8.1.9).
If necessary, increase the pressure to the maximum oil supply pressure of the tested valve and repeat the above test. In the case where it is impossible to monitor the output flow, the valve core displacement can also be monitored instead, which can obtain: 1) the position of the valve core at rated signal;
2) hysteresis;
3) polarity.
8.1.5 Threshold Characteristics Test
8.1.5.1 Overview
This test shall be performed to obtain the valve response to a reverse input signal. 8.1.5.2 Test Circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, g and j, and close all other valves. 8.1.5.3 Settings
Repeat the settings described in 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.5.4 Test Procedure
Repeat steps a) and b) in 8.1.4.4, then proceed as follows: a) Input a signal so that the output flow is 25% of the rated flow, then gradually reduce the input signal so that the flow also decreases accordingly. Slowly reduce the input signal to minimize the dynamic effect; 6
b) Record the input signal when the flow starts to decrease; Calculate the threshold value by calculating the signal change increment based on the algebraic difference of the two recorded signal values; c)
Repeat the test steps a) to c) at 75% of the rated flow; d)
Input the opposite signal and repeat the test steps a) to d); When testing the zero position of zero opening and negative cover valves, a similar test is used. f)
GB/T 15623:1—2003
Note: During the test, it may be necessary to adjust the sensitivity of the recorder. Figure 7 shows a typical recording diagram. The product acceptance test can use the AC signal level. 8.1.6 Throttling adjustment characteristic test
8.1.6.1 Overview
The purpose of this test is to determine the characteristics of each valve port of the main valve core to determine the valve's adaptability to different load conditions. Using flow sensor 11, record the flow through a valve port under different input signals (see Figure 8). Note: When measuring small flows, the measurement may be affected by contaminants trapped at the throttle port. 8.1.6.2 Flow from supply port P to working port A 8.1.6.2.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, e, g, j, and close all other valves. 8.1.6.2.2 Settings
Repeat the settings of 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.6.2.3 Test steps
Slowly increase the input signal from zero to the rated positive value, and use a plotter to record the flow curve from supply port P to working port A (see Figure 8).
8.1.6.3 Flow from port A to return port T 8.1.6.3. 1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, f, i, j, and close all other valves. 8.1.6.3.2 Settings
Repeat the settings of 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.6.3.3 Test steps
Slowly increase the input signal from zero to the rated negative value, and use a plotter to record the flow curve from working port A to return port T (see Figure 8).
8.1.6.4 Flow from supply port P to working port B 8.1.6.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves c, d, f, g, i, and close all other valves. 8.1.6.4.2 Setting
Repeat the setting of 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.6.4.3 Test Steps
Slowly increase the input signal from zero to the rated negative value, and use a plotter to record the flow curve from the supply port P to the return port B (see Figure 8).
8.1.6.5 Flow from the working oil port B to the return port T 8.1.6.5.1 Test Circuit
Establish the hydraulic test circuit shown in Figure 1, open valves d, e, f, h, j, and close all other valves. 8.1.6.5.2 Setting
Repeat the setting of 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.6.5.3 Test steps
Slowly increase the input signal from zero to the rated negative value, and use a drawing pen to record the flow curve from the working oil port B to the return oil port T (see Figure 8.
GB/T 15623.1—2003
Note: For valves with closed center, the tests in 8.1.6.2 to 8.1.6.5 can be repeated using a high-sensitivity flow sensor. 8.1.7 Output flow-load pressure difference characteristic test (open working oil port) 8.1.7.1 Overview
Perform the following steps to determine the characteristics of the output flow rate changing with the load pressure difference. 8.1.7.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, g, j and loading valve 13, and close all other valves. 8.1.7.3 Set
The oil supply pressure of the adjustment valve reaches the maximum oil supply pressure, and compensate the return oil pressure if necessary. Ensure that the set oil supply pressure remains constant throughout the test. A drop in the oil supply pressure indicates insufficient flow from the hydraulic power source. 8. 1.7.4 Test steps
Perform the test in the following steps:
Let the input signal change between the maximum negative value and the maximum positive value step by step several times. a)
Set the XY recorder, record the output flow on the Y axis and the load pressure difference on the X axis [see Figure 9a)]. c)
Adjust the input signal to 25% of the rated positive value. The drawing pen starts recording, and the loading valve 13 is slowly closed (see Figure 1). The curve of the output flow and the load pressure difference when the rated positive input signal is obtained. d)
Repeat steps c and d at 100%, 75% and 50% of the rated input signal [see Figure 9a)]. Repeat steps c to e at the negative input signal [see Figure 9a)]. f)
g) For valves with internal pressure compensation devices, perform the above test to determine the effect of the load pressure compensation device and record the test results as shown in Figure 10a).
8.1.8 Output flow-valve pressure drop characteristic test (open working oil port) 8.1.8.1 Overview
Perform the following steps to determine the characteristics of output flow changing with valve pressure drop. 8.1.8.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves a, b, c, d, gj and loading valve 13, and close all other valves. 8.1.8.3 Set the oil supply pressure of the adjustment valve to the maximum oil supply pressure and compensate the return pressure if necessary. Ensure that the set oil supply pressure remains constant throughout the test. A drop in the oil supply pressure indicates insufficient flow from the hydraulic power source. 8.1.8.4 Test steps Perform the test as follows: Make the input signal cycle between the maximum negative value and the maximum positive value several times a) b) Set up an XY recorder with the Y axis recording the output flow and the X axis recording the valve pressure drop (see Figure 9b)). c) Adjust the input signal to the rated positive value (100%). d) Close the loading valve 13, put down the drawing pen, and then slowly open the loading valve 13 (see Figure 1) to obtain a continuous change curve of the valve pressure drop-output flow at the rated positive input signal. Repeat steps c to e for the negative input signal (see Figure 9b). f)
For valves with internal pressure compensation, perform the above test to determine the effect of the load pressure compensation device and record the test results as shown in Figure 10b).
8.1.9 Limiting power characteristic test (open working oil port) 8.1.9.1 General
When the pressure drop of the valve is large, the hydraulic force acting on the valve plug will limit the flow through the valve, especially in the case of single-stage valves. The following test is required to determine this effect.
8.1.9.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj and close valves e, f, h, i. 8.1.9.3 Setting
Adjust the oil supply pressure so that the pressure drop of the valve is 10% of the rated pressure. 8.1.9.4 Test steps
GB/T 15623.1—2003
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sinusoidal signal (±5%), with a typical frequency of 0.2 Hz-0. 4 Hz;
The plotting pen starts recording;
Slowly increase the valve supply pressure, and the relationship curve between the output flow rate and the valve pressure drop can be measured. When the sinusoidal motion stops or the flow rate suddenly decreases, stop increasing the supply pressure and mark this point on the graph; d)
Repeat this test at other positive input signal amplitudes, such as 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 11); f)
Repeat steps a) to e) under negative input signals. 8.1.10
) Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.10.1 Overview
The following test should be carried out to determine the characteristics of the output flow rate changing with the oil temperature. The valve and amplifier should be placed in a constant temperature environment of 20℃.
8.1.10.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close all other valves. 8.1.10.3 Settings
Repeat the settings in 8.1.4.3.
8.1.10.4 Test steps
Perform the test as follows:
a) Use the continuous drawing/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis, and record the output flow rate or valve core position on the Y axis. [See Figure 12a)
Adjust the input signal so that the output flow is 10% of the rated output flow. c)
Record the relationship between the output flow or the valve core position and the oil temperature [See Figure 12a]. If necessary, repeat the above test at different input signals and valve pressure drops. d)
Draw a set of curves at different input signals and valve pressure drops within the selected temperature range. 8.1.11
Pressure difference-oil temperature characteristic test (closed working oil port) 8.1.11.1 Overview
The following steps shall be performed to determine the characteristics of the pressure difference with the oil temperature. The valve and amplifier shall be placed in a constant temperature environment of 20℃. 8.1.11.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves g and j, and close all other valves. 8.1.11.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.11.4 Test steps
Perform the test in the following steps:
a) Using the continuous plotting/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis and the pressure difference on the Y axis. [See Figure 12b)
Adjust the input signal so that the pressure difference is zero.
c) Record the relationship curve between the pressure difference and the oil temperature [See Figure 12b)]. d) Repeat the above test at each specified input signal and oil supply pressure. GB/T 15623.1--2003
8.1.12 Pressure gain-input signal characteristic test (closed working oil port) 8.1.12.1 Overview
The purpose of this test is to determine the pressure gain-input signal characteristics of the working oil ports A and B. Valves with positively covered valve cores are not subject to this test.
8.1.12.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.12.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.12.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the oil supply pressure amplitude can be effectively reached at the two working oil ports.
Use continuous mapping or recording methods to specify the appropriate range and deviation b)
Allow the input signal to change slowly within the range determined in a), and record the pressure values of the two closed ports A and B at the same time. c)
Note: Since this test is affected by the leakage characteristics of the valve and the volume of pressurized fluid, it may take several minutes to complete a scan. d) Draw the characteristic curve of load pressure-input signal of the closed oil ports of oil ports A and B on a pair of coordinate axes (see Figure 13). Mark the curve corresponding to each oil port
e) Draw the characteristic curve of load pressure difference-input signal (see Figure 14). 8.1.13 Pressure zero drift
8.1.13.1 Test steps
Perform the test in the following steps:
a) When the system pressure is 10MPa (100 bar), adjust the input signal so that the pressures of oil ports A and B are equal, and record the input signal value at this time.
b) Set the oil supply pressure at 5MPa (50 bar) and repeat the test in a) above. c) Set the oil supply pressure at 20MPa (200 bar) and repeat the test in a) above. 8.1.13.2 Conclusion
The change of input signal (expressed as a percentage of the maximum input signal) forms a pressure zero drift that adapts to the change of oil supply pressure. 8.1.14 Failure protection function test
Perform the test as follows:
a) Verify the inherent failure protection characteristics of the valve, such as the loss of input signal, loss or reduction of electrical power, loss or reduction of hydraulic power, loss of feedback signal, etc. b) Verify the performance of any dedicated failure protection function device installed in the valve by monitoring the valve core position. c) If necessary, select different input signals and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Keep the pipe lengths from ports A and B to the actuator as short as possible. 8.2.1.3 Place the accumulator as close as possible to the P port of the valve. Provide a constant pressure of 10 MPa (100 bar) or rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.4
8.2.1.5
Use a frequency response analyzer, oscilloscope or other suitable electronic device to measure the amplitude of the output signal and its phase shift relative to the input signal.
8.2.1.6 Measure the output signal by one of the following methods: a) Use a low friction (pressure drop not exceeding 0.3 MPa), small inertia (with a bandwidth at least greater than the maximum 10 including the volume effect of trapped oil)4 Test steps
Perform the test as follows:
Let the input signal cycle between the maximum negative value and the maximum positive value for several times a)
b) Set up an XY recorder, record the output flow on the Y axis and the valve pressure drop on the X axis [see Figure 9b)]. c) Adjust the input signal to the rated positive value (100%). d)
Close the loading valve 13, put down the drawing pen, and then slowly open the loading valve 13 (see Figure 1) to obtain a continuous change curve of the valve pressure drop-output flow rate when the rated positive input signal is applied.
Repeat steps c to e for the negative input signal (see Figure 9b). f)
For valves with internal pressure compensation devices, perform the above test to determine the effect of the load pressure compensation device and record the test results as shown in Figure 10b).
8.1.9 Limiting power characteristic test (opening the working oil port) 8.1.9.1 Overview
When the valve pressure drop is large, the hydraulic force acting on the valve core will limit the flow through the valve, especially in the case of single-stage valves. The following test is required to determine this effect.
8.1.9.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close valves e, f, h, i. 8.1.9.3 Setting
Adjust the oil supply pressure so that the valve pressure drop is 10% of the rated pressure. 8.1.9.4 Test steps
GB/T 15623.1—2003
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sinusoidal signal (±5%), with a typical frequency of 0.2 Hz-0. 4 Hz;
The plotting pen starts recording;
Slowly increase the valve supply pressure, and the relationship curve between the output flow rate and the valve pressure drop can be measured. When the sinusoidal motion stops or the flow rate suddenly decreases, stop increasing the supply pressure and mark this point on the graph; d)
Repeat this test at other positive input signal amplitudes, such as 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 11); f)
Repeat steps a) to e) under negative input signals. 8.1.10
) Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.10.1 Overview
The following test should be carried out to determine the characteristics of the output flow rate changing with the oil temperature. The valve and amplifier should be placed in a constant temperature environment of 20℃.
8.1.10.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close all other valves. 8.1.10.3 Settings
Repeat the settings in 8.1.4.3.
8.1.10.4 Test steps
Perform the test as follows:
a) Use the continuous drawing/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis, and record the output flow rate or valve core position on the Y axis. [See Figure 12a)
Adjust the input signal so that the output flow is 10% of the rated output flow. c)
Record the relationship between the output flow or the valve core position and the oil temperature [See Figure 12a]. If necessary, repeat the above test at different input signals and valve pressure drops. d)
Draw a set of curves at different input signals and valve pressure drops within the selected temperature range. 8.1.11
Pressure difference-oil temperature characteristic test (closed working oil port) 8.1.11.1 Overview
The following steps shall be performed to determine the characteristics of the pressure difference with the oil temperature. The valve and amplifier shall be placed in a constant temperature environment of 20℃. 8.1.11.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves g and j, and close all other valves. 8.1.11.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.11.4 Test steps
Perform the test in the following steps:
a) Using the continuous plotting/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis and the pressure difference on the Y axis. [See Figure 12b)
Adjust the input signal so that the pressure difference is zero.
c) Record the relationship curve between the pressure difference and the oil temperature [See Figure 12b)]. d) Repeat the above test at each specified input signal and oil supply pressure. GB/T 15623.1--2003
8.1.12 Pressure gain-input signal characteristic test (closed working oil port) 8.1.12.1 Overview
The purpose of this test is to determine the pressure gain-input signal characteristics of the working oil ports A and B. Valves with positively covered valve cores are not subject to this test.
8.1.12.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.12.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.12.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the oil supply pressure amplitude can be effectively reached at the two working oil ports.
Use continuous mapping or recording methods to specify the appropriate range and deviation b)
Allow the input signal to change slowly within the range determined in a), and record the pressure values of the two closed ports A and B at the same time. c)
Note: Since this test is affected by the leakage characteristics of the valve and the volume of pressurized fluid, it may take several minutes to complete a scan. d) Draw the characteristic curve of load pressure-input signal of the closed oil ports of oil ports A and B on a pair of coordinate axes (see Figure 13). Mark the curve corresponding to each oil port
e) Draw the characteristic curve of load pressure difference-input signal (see Figure 14). 8.1.13 Pressure zero drift
8.1.13.1 Test steps
Perform the test in the following steps:
a) When the system pressure is 10MPa (100 bar), adjust the input signal so that the pressures of oil ports A and B are equal, and record the input signal value at this time.
b) Set the oil supply pressure at 5MPa (50 bar) and repeat the test in a) above. c) Set the oil supply pressure at 20MPa (200 bar) and repeat the test in a) above. 8.1.13.2 Conclusion
The change of input signal (expressed as a percentage of the maximum input signal) forms a pressure zero drift that adapts to the change of oil supply pressure. 8.1.14 Failure protection function test
Perform the test as follows:
a) Verify the inherent failure protection characteristics of the valve, such as the loss of input signal, loss or reduction of electrical power, loss or reduction of hydraulic power, loss of feedback signal, etc. b) Verify the performance of any dedicated failure protection function device installed in the valve by monitoring the valve core position. c) If necessary, select different input signals and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Keep the pipe lengths from ports A and B to the actuator as short as possible. 8.2.1.3 Place the accumulator as close as possible to the P port of the valve. Provide a constant pressure of 10 MPa (100 bar) or rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.4
8.2.1.5
Use a frequency response analyzer, oscilloscope or other suitable electronic device to measure the amplitude of the output signal and its phase shift relative to the input signal.
8.2.1.6 Measure the output signal by one of the following methods: a) Use a low friction (pressure drop not exceeding 0.3 MPa), small inertia (with a bandwidth at least greater than the maximum 10 including the volume effect of trapped oil)4 Test steps
Perform the test as follows:
Let the input signal cycle between the maximum negative value and the maximum positive value for several times a)
b) Set up an XY recorder, record the output flow on the Y axis and the valve pressure drop on the X axis [see Figure 9b)]. c) Adjust the input signal to the rated positive value (100%). d)
Close the loading valve 13, put down the drawing pen, and then slowly open the loading valve 13 (see Figure 1) to obtain a continuous change curve of the valve pressure drop-output flow rate when the rated positive input signal is applied.
Repeat steps c to e for the negative input signal (see Figure 9b). f)
For valves with internal pressure compensation devices, perform the above test to determine the effect of the load pressure compensation device and record the test results as shown in Figure 10b).
8.1.9 Limiting power characteristic test (opening the working oil port) 8.1.9.1 Overview
When the valve pressure drop is large, the hydraulic force acting on the valve core will limit the flow through the valve, especially in the case of single-stage valves. The following test is required to determine this effect.
8.1.9.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close valves e, f, h, i. 8.1.9.3 Setting
Adjust the oil supply pressure so that the valve pressure drop is 10% of the rated pressure. 8.1.9.4 Test steps
GB/T 15623.1—2003
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sinusoidal signal (±5%), with a typical frequency of 0.2 Hz-0. 4 Hz;
The plotting pen starts recording;
Slowly increase the valve supply pressure, and the relationship curve between the output flow rate and the valve pressure drop can be measured. When the sinusoidal motion stops or the flow rate suddenly decreases, stop increasing the supply pressure and mark this point on the graph; d)
Repeat this test at other positive input signal amplitudes, such as 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 11); f)
Repeat steps a) to e) under negative input signals. 8.1.10
) Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.10.1 Overview
The following test should be carried out to determine the characteristics of the output flow rate changing with the oil temperature. The valve and amplifier should be placed in a constant temperature environment of 20℃.
8.1.10.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close all other valves. 8.1.10.3 Settings
Repeat the settings in 8.1.4.3.
8.1.10.4 Test steps
Perform the test as follows:
a) Use the continuous drawing/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis, and record the output flow rate or valve core position on the Y axis. [See Figure 12a)
Adjust the input signal so that the output flow is 10% of the rated output flow. c)
Record the relationship between the output flow or the valve core position and the oil temperature [See Figure 12a]. If necessary, repeat the above test at different input signals and valve pressure drops. d)
Draw a set of curves at different input signals and valve pressure drops within the selected temperature range. 8.1.11
Pressure difference-oil temperature characteristic test (closed working oil port) 8.1.11.1 Overview
The following steps shall be performed to determine the characteristics of the pressure difference with the oil temperature. The valve and amplifier shall be placed in a constant temperature environment of 20℃. 8.1.11.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves g and j, and close all other valves. 8.1.11.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.11.4 Test steps
Perform the test in the following steps:
a) Using the continuous plotting/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis and the pressure difference on the Y axis. [See Figure 12b)
Adjust the input signal so that the pressure difference is zero.
c) Record the relationship curve between the pressure difference and the oil temperature [See Figure 12b)]. d) Repeat the above test at each specified input signal and oil supply pressure. GB/T 15623.1--2003
8.1.12 Pressure gain-input signal characteristic test (closed working oil port) 8.1.12.1 OverviewWww.bzxZ.net
The purpose of this test is to determine the pressure gain-input signal characteristics of the working oil ports A and B. Valves with positively covered valve cores are not subject to this test.
8.1.12.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.12.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.12.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the oil supply pressure amplitude can be effectively reached at the two working oil ports.
Use continuous mapping or recording methods to specify the appropriate range and deviation b)
Allow the input signal to change slowly within the range determined in a), and record the pressure values of the two closed ports A and B at the same time. c)
Note: Since this test is affected by the leakage characteristics of the valve and the volume of pressurized fluid, it may take several minutes to complete a scan. d) Draw the characteristic curve of load pressure-input signal of the closed oil ports of oil ports A and B on a pair of coordinate axes (see Figure 13). Mark the curve corresponding to each oil port
e) Draw the characteristic curve of load pressure difference-input signal (see Figure 14). 8.1.13 Pressure zero drift
8.1.13.1 Test steps
Perform the test in the following steps:
a) When the system pressure is 10MPa (100 bar), adjust the input signal so that the pressures of oil ports A and B are equal, and record the input signal value at this time.
b) Set the oil supply pressure at 5MPa (50 bar) and repeat the test in a) above. c) Set the oil supply pressure at 20MPa (200 bar) and repeat the test in a) above. 8.1.13.2 Conclusion
The change of input signal (expressed as a percentage of the maximum input signal) forms a pressure zero drift that adapts to the change of oil supply pressure. 8.1.14 Failure protection function test
Perform the test as follows:
a) Verify the inherent failure protection characteristics of the valve, such as the loss of input signal, loss or reduction of electrical power, loss or reduction of hydraulic power, loss of feedback signal, etc. b) Verify the performance of any dedicated failure protection function device installed in the valve by monitoring the valve core position. c) If necessary, select different input signals and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Keep the pipe lengths from ports A and B to the actuator as short as possible. 8.2.1.3 Place the accumulator as close as possible to the P port of the valve. Provide a constant pressure of 10 MPa (100 bar) or rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.4
8.2.1.5
Use a frequency response analyzer, oscilloscope or other suitable electronic device to measure the amplitude of the output signal and its phase shift relative to the input signal.
8.2.1.6 Measure the output signal by one of the following methods: a) Use a low friction (pressure drop not exceeding 0.3 MPa), small inertia (with a bandwidth at least greater than the maximum 10 including the volume effect of trapped oil)1 Overview
When the pressure drop of the valve is large, the hydraulic force acting on the valve core will limit the flow through the valve, especially in the case of single-stage valves. The following test is required to determine this effect.
8.1.9.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close valves e, f, h, i. 8.1.9.3 Setting
Adjust the oil supply pressure so that the pressure drop of the valve is 10% of the rated pressure. 8.1.9.4 Test steps
GB/T 15623.1—2003
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sinusoidal signal (±5%), with a typical frequency of 0.2 Hz-0. 4 Hz;
The plotting pen starts recording;
Slowly increase the valve supply pressure, and the relationship curve between the output flow rate and the valve pressure drop can be measured. When the sinusoidal motion stops or the flow rate suddenly decreases, stop increasing the supply pressure and mark this point on the graph; d)
Repeat this test at other positive input signal amplitudes, such as 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 11); f)
Repeat steps a) to e) under negative input signals. 8.1.10
) Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.10.1 Overview
The following test should be carried out to determine the characteristics of the output flow rate changing with the oil temperature. The valve and amplifier should be placed in a constant temperature environment of 20℃.
8.1.10.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close all other valves. 8.1.10.3 Settings
Repeat the settings in 8.1.4.3.
8.1.10.4 Test steps
Perform the test as follows:
a) Use the continuous drawing/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis, and record the output flow rate or valve core position on the Y axis. [See Figure 12a)
Adjust the input signal so that the output flow is 10% of the rated output flow. c)
Record the relationship between the output flow or the valve core position and the oil temperature [See Figure 12a]. If necessary, repeat the above test at different input signals and valve pressure drops. d)
Draw a set of curves at different input signals and valve pressure drops within the selected temperature range. 8.1.11
Pressure difference-oil temperature characteristic test (closed working oil port) 8.1.11.1 Overview
The following steps shall be performed to determine the characteristics of the pressure difference with the oil temperature. The valve and amplifier shall be placed in a constant temperature environment of 20℃. 8.1.11.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves g and j, and close all other valves. 8.1.11.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.11.4 Test steps
Perform the test in the following steps:
a) Using the continuous plotting/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis and the pressure difference on the Y axis. [See Figure 12b)
Adjust the input signal so that the pressure difference is zero.
c) Record the relationship curve between the pressure difference and the oil temperature [See Figure 12b)]. d) Repeat the above test at each specified input signal and oil supply pressure. GB/T 15623.1--2003
8.1.12 Pressure gain-input signal characteristic test (closed working oil port) 8.1.12.1 Overview
The purpose of this test is to determine the pressure gain-input signal characteristics of the working oil ports A and B. Valves with positively covered valve cores are not subject to this test.
8.1.12.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.12.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.12.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the oil supply pressure amplitude can be effectively reached at the two working oil ports.
Use continuous mapping or recording methods to specify the appropriate range and deviation b)
Allow the input signal to change slowly within the range determined in a), and record the pressure values of the two closed ports A and B at the same time. c)
Note: Since this test is affected by the leakage characteristics of the valve and the volume of pressurized fluid, it may take several minutes to complete a scan. d) Draw the characteristic curve of load pressure-input signal of the closed oil ports of oil ports A and B on a pair of coordinate axes (see Figure 13). Mark the curve corresponding to each oil port
e) Draw the characteristic curve of load pressure difference-input signal (see Figure 14). 8.1.13 Pressure zero drift
8.1.13.1 Test steps
Perform the test in the following steps:
a) When the system pressure is 10MPa (100 bar), adjust the input signal so that the pressures of oil ports A and B are equal, and record the input signal value at this time.
b) Set the oil supply pressure at 5MPa (50 bar) and repeat the test in a) above. c) Set the oil supply pressure at 20MPa (200 bar) and repeat the test in a) above. 8.1.13.2 Conclusion
The change of input signal (expressed as a percentage of the maximum input signal) forms a pressure zero drift that adapts to the change of oil supply pressure. 8.1.14 Failure protection function test
Perform the test as follows:
a) Verify the inherent failure protection characteristics of the valve, such as the loss of input signal, loss or reduction of electrical power, loss or reduction of hydraulic power, loss of feedback signal, etc. b) Verify the performance of any dedicated failure protection function device installed in the valve by monitoring the valve core position. c) If necessary, select different input signals and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Keep the pipe lengths from ports A and B to the actuator as short as possible. 8.2.1.3 Place the accumulator as close as possible to the P port of the valve. Provide a constant pressure of 10 MPa (100 bar) or rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.4
8.2.1.5
Use a frequency response analyzer, oscilloscope or other suitable electronic device to measure the amplitude of the output signal and its phase shift relative to the input signal.
8.2.1.6 Measure the output signal by one of the following methods: a) Use a low friction (pressure drop not exceeding 0.3 MPa), small inertia (with a bandwidth at least greater than the maximum 10 including the volume effect of trapped oil)1 Overview
When the pressure drop of the valve is large, the hydraulic force acting on the valve core will limit the flow through the valve, especially in the case of single-stage valves. The following test is required to determine this effect.
8.1.9.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close valves e, f, h, i. 8.1.9.3 Setting
Adjust the oil supply pressure so that the pressure drop of the valve is 10% of the rated pressure. 8.1.9.4 Test steps
GB/T 15623.1—2003
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sinusoidal signal (±5%), with a typical frequency of 0.2 Hz-0. 4 Hz;
The plotting pen starts recording;
Slowly increase the valve supply pressure, and the relationship curve between the output flow rate and the valve pressure drop can be measured. When the sinusoidal motion stops or the flow rate suddenly decreases, stop increasing the supply pressure and mark this point on the graph; d)
Repeat this test at other positive input signal amplitudes, such as 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 11); f)
Repeat steps a) to e) under negative input signals. 8.1.10
) Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.10.1 Overview
The following test should be carried out to determine the characteristics of the output flow rate changing with the oil temperature. The valve and amplifier should be placed in a constant temperature environment of 20℃.
8.1.10.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, c, d, gj, and close all other valves. 8.1.10.3 Settings
Repeat the settings in 8.1.4.3.
8.1.10.4 Test steps
Perform the test as follows:
a) Use the continuous drawing/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis, and record the output flow rate or valve core position on the Y axis. [See Figure 12a)
Adjust the input signal so that the output flow is 10% of the rated output flow. c)
Record the relationship between the output flow or the valve core position and the oil temperature [See Figure 12a]. If necessary, repeat the above test at different input signals and valve pressure drops. d)
Draw a set of curves at different input signals and valve pressure drops within the selected temperature range. 8.1.11
Pressure difference-oil temperature characteristic test (closed working oil port) 8.1.11.1 Overview
The following steps shall be performed to determine the characteristics of the pressure difference with the oil temperature. The valve and amplifier shall be placed in a constant temperature environment of 20℃. 8.1.11.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves g and j, and close all other valves. 8.1.11.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.11.4 Test steps
Perform the test in the following steps:
a) Using the continuous plotting/recording method, select a recorder with an appropriate range, record the oil temperature on the X axis and the pressure difference on the Y axis. [See Figure 12b)
Adjust the input signal so that the pressure difference is zero.
c) Record the relationship curve between the pressure difference and the oil temperature [See Figure 12b)]. d) Repeat the above test at each specified input signal and oil supply pressure. GB/T 15623.1--2003
8.1.12 Pressure gain-input signal characteristic test (closed working oil port) 8.1.12.1 Overview
The purpose of this test is to determine the pressure gain-input signal characteristics of the working oil ports A and B. Valves with positively covered valve cores are not subject to this test.
8.1.12.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves g and j, and close all other valves. 8.1.12.3 Setting
Adjust the oil supply pressure of the test valve to the maximum oil supply pressure. 8.1.12.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the oil supply pressure amplitude can be effectively reached at the two working oil ports.
Use continuous mapping or recording methods to specify the appropriate range and deviation b)
Allow the input signal to change slowly within the range determined in a), and record the pressure values of the two closed ports A and B at the same time. c)
Note: Since this test is affected by the leakage characteristics of the valve and the volume of pressurized fluid, it may take several minutes to complete a scan. d) Draw the characteristic curve of load pressure-input signal of the closed oil ports of oil ports A and B on a pair of coordinate axes (see Figure 13). Mark the curve corresponding to each oil port
e) Draw the characteristic curve of load pressure difference-input signal (see Figure 14). 8.1.13 Pressure zero drift
8.1.13.1 Test steps
Perform the test in the following steps:
a) When the system pressure is 10MPa (100 bar), adjust the input signal so that the pressures of oil ports A and B are equal, and record the input signal value at this time.
b) Set the oil supply pressure at 5MPa (50 bar) and repeat the test in a) above. c) Set the oil supply pressure at 20MPa (200 bar) and repeat the test in a) above. 8.1.13.2 Conclusion
The change of input signal (expressed as a percentage of the maximum input signal) forms a pressure zero drift that adapts to the change of oil supply pressure. 8.1.14 Failure protection function test
Perform the test as follows:
a) Verify the inherent failure protection characteristics of the valve, such as the loss of input signal, loss or reduction of electrical power, loss or reduction of hydraulic power, loss of feedback signal, etc. b) Verify the performance of any dedicated failure protection function device installed in the valve by monitoring the valve core position. c) If necessary, select different input signals and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Keep the pipe lengths from ports A and B to the actuator as short as possible. 8.2.1.3 Place the accumulator as close as possible to the P port of the valve. Provide a constant pressure of 10 MPa (100 bar) or rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.4
8.2.1.5
Use a frequency response analyzer, oscilloscope or othe
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