GB 6075-1985 Basis for the formulation of machine vibration standards
Some standard content:
National Standard of the People's Republic of China
The basis for laying down standards of vibration of machines
UDC 621.8.034
GB6075-85
This standard measures the mechanical vibration intensity of a single machine with a speed of 10-200s: (600-12000rmin). It only involves the vibration of the machine surface, bearings and installation points within the frequency range of 10-1000Hz. At the same time, the performance of the machine is considered to ensure that the machine can work safely, the stress caused by the movement of key components, the performance of the instrument measuring this mechanical movement, the impact of machine vibration on the surrounding environment (such as the impact on nearby instruments, machines, etc.), and the impact on the human body or mind. It is a basic standard for formulating various machine vibration standards.
The vibration measured on the surface of the machine can be a reflection of the stress or motion state inside the machine, but it does not always represent the actual dynamic stress or motion state of the most dangerous parts, nor can it guarantee that excessive vibration stress will not occur inside the machine. A detailed description of the stress and motion state of the machine is very complex and not suitable for practical application. For industrial applications, it is practical to select a single value to determine the vibration state of the machine during the test, which can provide a reliable evaluation consistent with practical experience for most situations encountered in practice.
This standard stipulates the movement intensity as a characteristic quantity describing the vibration state of the machine, which serves as the basis for classifying various machines. Based on theoretical considerations and practical experience, the root mean square value of the vibration velocity is specified as the unit for measuring vibration intensity. When only simple measurements are required, using vibration intensity as an evaluation standard can obtain a fairly reliable evaluation. In special occasions, when more accurate measurements are required, each parameter of concern should be measured.
This standard is equivalent to the international standard ISO2372-1974 "Mechanical movement of machines with a speed of 10 to 200 s - Basis for the determination of evaluation criteria".
1 Scope of application
This standard defines the basis for evaluating the movement of machines in the range of 10 to 200 s: (600 to 12000 r/min). This standard can be used to compare the results measured under similar conditions for similar machines. The purpose of this standard is to evaluate the normal vibration of machines related to reliability, safety and human perception.
This standard is only applicable to vibrations measured from the surface of the machine (such as the bearing cover), with a frequency range of 10 to 1000 Hz and a speed range of 10 to 200 s (600 to 12000 r/min). When evaluating special machines, the values of the classification can be specified according to the criteria established in this standard.
This standard includes explanations of terms, guidelines for measurement conditions and recommended vibration severity ranges. An example of the proposed classification method is given in Appendix A (reference). The method for converting the root mean square value of velocity into the displacement value is given in Appendix B (reference).
2 Explanation of terms
This standard specifies the root mean square value of the speed as a parameter to characterize the vibration severity of the machine. For simple harmonic vibrations with an instantaneous velocity of V,-cosw;ti-1,2n (n is a positive integer (peak value) and vibrations composed of several simple harmonic vibrations of different frequencies, according to the definition, the root mean square value of the vibration velocity can be used to measure the movement intensity, and an electrical instrument with a square detection characteristic can be used to measure and directly display the movement intensity. The root mean square value of the measured movement velocity can be calculated from the following formula based on the change of the measured movement velocity with time. Issued by the National Bureau of Standards in 1985-06~06
19860401 implementation
GB 6075-85
T2 ()dt
From the spectrum analysis, we know that the amplitude of acceleration, velocity or displacement (α, min, S,}=1,2·n) is the coefficient of angular velocity. According to the amplitude of displacement S, the amplitude of vibration velocity, or the amplitude of vibration acceleration, the Yamashita formula can calculate the root mean square value of the limit velocity:
+)(S#++...+)
）2++
When only two frequency vibration components are included and the effective values are Umi and Umax, the Yamashita formula can be approximately defined to obtain zrm(
There is at least one on a machine. Or several key parts, these points are of great significance for understanding the vibration of the machine. These points are generally the base of the machine (that is, the points fixed to the foundation) or the bearings. By measuring the vertical vibration component or the horizontal vibration component at these selected positions, the maximum average root square value of the vibration velocity can be calculated by direct measurement or according to formulas (1), (2) and (3), thereby obtaining the vibration intensity of the machine under given working or environmental conditions. 3 General criteria for measuring vibration intensity
In general criteria, only the most important conditions are considered, but it also applies to certain specific conditions. 3.1 The measuring instrument
should be correct Select the vibration intensity measuring instrument to indicate and record the movement of the machine being measured. Before carrying out the vibration measurement, a careful check should be made to ensure that the measuring instrument can operate accurately within the required frequency range and speed range under the main environmental conditions (such as temperature, magnetic field, surface finish, etc.). The response and accuracy of the instrument within the entire measurement range should be known. The vibration intensity measuring instrument used should be inspected and approved by the metrology department. Calibrate the entire measurement system before use to ensure that its accuracy meets the requirements. The installation should be carried out carefully and reasonably, and ensure that it will not significantly affect the vibration characteristics of the machine. 3.2 Test timing Fixing of the machine
The fixing of the machine has a great influence on the measured machine vibration value. Three possible fixing conditions are given in 3.2.1 to 3.2.3. 3.2.1 Soft installation of the machine
When the machine is softly installed, it is easy to measure the vibration level of the machine under test. At this time, the machine should be installed on an elastic test base. The lowest natural frequency of the machine when installed in this way should be less than one-fourth of the lowest excitation frequency. In machines with rotating elements, its natural frequency should be lower than one-fourth of the lowest excitation frequency of the equipment. In addition, the effective mass* of the elastic system should not exceed 1/4 of the mass of the machine under test (see Figure 1).
*Effective mass refers to the mass of the soft installation system that should be affected during the embedding process, not its actual mass. 430
3.2.2 Installation of the machine on a soft mounting base GE6075-85
Figure] Schematic diagram of soft mounting of the machine
For machines that are strictly intended to be used on a rigid base, the handling level can only be measured when the machine is installed on such a soft mounting base for testing. The following two types of bases can be used: a. The base is lighter than the machine and is only used to strengthen the machine. In this case, the mass of the tested base should be less than one-fourth of the mass of the machine.
h. The base is heavier than the machine and is used as a rigid foundation to fix the foundation screws of the machine. In this case, the mass of the tested foundation should be at least twice the mass of the machine.
In both cases, no excessive structural resonance should occur within the test range. After the base and machine are installed together, soft mounting is performed so that the natural frequency of the entire system thus constructed is less than one-fourth of the lowest excitation frequency of the machine. 3.2.3 Mounting of the machine on a structural foundation
If the type and size of the machine to be tested are not suitable for soft mounting, it is usually mounted on a given structural foundation. In this case, care must be taken that the foundation (including the soil) has similar dynamic characteristics in order to make a correct comparison of the handling severity of similar machines; if these conditions are not met, the vibration severity can only be defined for each specific case. Note: For large machines, which can only be tested on site, these general principles are still applicable, but additional requirements must be supplemented according to the respective situation.
3.3 Measuring points
The measuring points are preferably selected at the point where the vibration energy is most transferred to the elastic foundation or other parts of the system. For machines with rotating masses, it is recommended to select the measuring points at the bearings or at the intersection of the machine. Other measuring points can also be selected in each case. For example, the reference points in Figure 2. The measurement is carried out in the direction of the phase. -131
GB 6075—85
Figure 2 Optional measuring points for small machines (measurement direction at bearings, supports and valves) 3.4 Working conditions during the test
Before the test, the test conditions such as temperature, load, speed, etc. should be specified, and the actual conditions should be recorded during the test. For machines with variable speed, measurements should be carried out at multiple speeds to determine the resonance frequency and the effect of the resonance on the measured moving characteristics. 4 Scales for evaluating vibration intensity
4.1 Range
Vibrations with the same RMS velocity in the frequency range of 10 to 1000 Hz are considered to have alternating vibration severity. The ratio between two adjacent levels in the table below is 1:1.6, which means a difference of 4 dB. The difference of 4 dB represents a significant change in the vibration velocity of most machine vibration responses. 4.2 Evaluation criteria for specific types of machines
The classification range of vibration severity values should be selected based on the mass and size of the vibrating body, the characteristics of the installation system, the output power of the machine and the use status. For different machines, the purpose and environment of their use must be considered to determine the use of different ranges in the table below. 132
GB 6075-85
Range of vibration severity (10～1000Hz) Range of vibration severity
0.071~0.112
0.112 ~0.18
0.28 ~0.45
0.45 ~0.71Www.bzxZ.net
0.71 ~1.12
7.1 ~11.2
18~ 28
28 45
GB 6075-85
Appendix A
(Reference number)
To illustrate how the proposed classification method is used. The following example is given for a specific type of machine. This is only a simple example. Other classification methods can also be selected according to the specific situation under study. Where circumstances permit, inferences should be given about the acceptable dynamic severity of a particular type of machine. Pre-process tests have shown that the following classification is appropriate for most applications. Category 1: Engines and machine parts that are integral with the whole machine under normal operating conditions (production switches with an output of 15 kW or more are typical examples of this type of machine). Category 2: Medium-sized machines without a dedicated foundation (typical examples of motors with an output of 5 to 75 kW), engines and machines rigidly mounted on a dedicated foundation (less than 300 kW). Category 3: Large prime movers and other large machines with rotating masses mounted on a very rigid (in the direction of vibration) heavy foundation. Category 4: Large prime movers and other large machines with rotating masses (e.g. turbine units, especially turbine units of light structure) mounted on a very rigid (in the direction of vibration) foundation. Category 5: Machines and mechanical drive systems with unbalanced inertial forces mounted on a very rigid (in the direction of vibration) foundation (unbalanced inertial forces are caused by the reciprocating parts of the machine). Category 6: Machines and mechanical drive systems with unbalanced inertia (caused by the dynamic driving parts of the machine) installed on a foundation with very low rigidity (in the vibration measurement direction). Machines with loose couplings and rotating masses, such as the shaft in a grinder. Machines whose variable unbalanced forces can work in a system without connecting parts, such as coring machines, mobile screens used in processing, dynamic fatigue testing machines and vibration tables.
A large number of tests were carried out on the first four types as examples, and their evaluation was obtained, as shown in the following table. The vibration intensity chain increases by 2 levels, and it is recommended to be divided into four levels of A, B, (, I) for evaluating quality standards. When the maximum value measured at important measuring points (especially at the bearings) is within the corresponding range in the following table, the motor or machine can be evaluated according to the values in the following table. Ranges of vibration severity and examples of their application to small machines (class 1), medium machines (class 2), large machines (class 3) and turbine machines (class 4) Ranges of vibration severity RMS values of speed at the limits of the range Examples of determining the quality of a machine Class 1 Class 4 Class 5 It is easy to distinguish between the horizontal and vertical vibration levels measured on machines of class 1. In most cases the tolerances for vibration are twice the tolerances for vibration. Machines of classes 5 and 6, especially reciprocating engines, vary greatly in their structure and in the relative influence of inertial forces, so that their dynamic characteristics vary greatly. It is therefore difficult to classify them as in the first four classes. In machines of class 5 it is easy to distinguish between the multiple frequencies produced by the machine and to excite relatively high scratch frequencies corresponding to its rigid mounting system. For machines of this type, it is possible to use a vibration velocity root mean square value of 20 to 30 mm/s or more, which will not cause any trouble. In addition, if the coupling is effective, large displacements may occur at points at the same distance from the center of gravity. In the sixth type of machines, elastically mounted machines allow larger tolerances. This machine has a diaphragm effect, and the force transmitted from the left mounting point to the periphery is very small. In this case, the vibration level measured next to the machine on the mounting system is lower than the vibration level measured when the machine is fixed on a relatively rigid support. On high-speed starting machines, root mean square values of 50 mm/s or more can be measured. Additional parts may have higher vibration velocities because they are often affected by resonance. When passing through their vibration zone, root mean square values of velocities of the order of 500 mm/s may appear in a short torsion bar. .5
GB 6075--85
Appendix B
Calculation of displacement amplitude from the root mean square value of velocity and given frequency (reference number)
In many standards, the root mean square value of velocity is usually used in the frequency range of 10 to 1000 Hz: is the number, but in some cases it is important to know the displacement amplitude of the main frequency in the measured vibration spectrum. In addition, the displacement amplitude is also used as a parameter in some standards, so the root mean square value of velocity must be converted into peak displacement: only a single-frequency positive wave can be converted from vibration velocity to vibration displacement. If the extreme vibration velocity of the frequency is known, the peak displacement can be calculated by the following formula:
In the formula: is the displacement peak;
is the root mean square value of the vibration velocity with a frequency of: 02 is the frequency.
())
Example:
Given the intensity of vibration (RMS value of velocity) is 4mms, that is, the RMS value of the maximum vibration velocity in the frequency range of 10-1000! does not exceed 4mms. Spectrum analysis shows that the main frequency is 2.51z, and the RMS value of the vibration velocity is 2.8mms. Therefore, the peak value (calculated using the above relationship) is: (2.) -1).027 mm (or 271m)
3r= 0.225 (
The diagram of the above equation is given in the figure.
Note that the measurement speed is the basic parameter for measuring vibration intensity. It is very important. Generally speaking, it is inappropriate to estimate the vibration intensity value based on the displacement amplitude of the main frequency. Only when it is a single-frequency vibration, 1. When the root mean square value of the vibration velocity can be determined within the entire range of 10100011z (using the above equation B1), can the vibration intensity be calculated from the displacement amplitude of the main frequency. 136
GB6075—85
The change of displacement peak frequency at different root mean square values of velocity mo
Additional notes:
6075—85
This standard was drafted by the China National Institute of Metrology. The main drafter of this standard is Guo Yingchuan.2
18~ 28
28 45
GB 6075-—85
Appendix A
(Reference number)
In order to illustrate how the proposed classification method is used. The following examples of specific types of machines are given. This is only a simple example. Other classification methods can also be selected according to the specific situation under study. When the situation permits, the inferred values of the dynamic severity of specific types of machines should be given. Preliminary tests have shown that for most applications, the following classification method is appropriate. Class 1: Engines and machine parts that are integrated with the whole machine under normal operating conditions (production switches above 15kW are typical examples of this type of machine).
Class 2: Medium-sized machines without a dedicated basis (a typical example is a motor with an output power of 5-75kW), engines and machines rigidly mounted on a dedicated basis (below 300kW). Category 3: Large prime movers and other machines with rotating masses mounted on a very rigid (in the direction of vibration) heavy foundation.
Category 4: Large prime movers and other large machines with rotating masses (such as turbine sets, especially light turbine sets) mounted on a very rigid (in the direction of vibration) foundation. Category 5: Machines and mechanical drive systems with unbalanced inertial forces (the unbalanced inertial forces are caused by the reciprocating parts of the machine) mounted on a very rigid (in the direction of vibration) foundation. Category 6: Machines and mechanical drive systems with unbalanced inertia (caused by the reciprocating moving parts of the machine) mounted on a very rigid (in the direction of vibration) foundation. Machines with loose couplings and rotating masses, such as the shaft in a grinder. Machines whose variable unbalanced forces can work independently without connecting parts, such as coring machines, mobile screens used in processing, dynamic fatigue testing machines and vibration tables.
A large number of tests were carried out using the first four as examples, and their evaluations were obtained, as shown in the following table. The vibration severity is calculated in two levels, and it is recommended to be divided into four levels of A, B, (, I) for evaluating quality. When the maximum value measured at the important measuring points (especially the bearings) is within the corresponding range in the table below, the motor or machine can be evaluated according to the values in the table below. Vibration severity range and examples of their application to small machines (class 1), large machines (class 2), large machines (class 3) and turbine machines (class 4) Range of vibration severity Classification range Speed root mean square value at the limit of the range Examples of judging the quality of various machines Class 1 Class 4 Class 5 G36075-85 It is easy to distinguish the vibration levels in the horizontal and vertical directions measured on the first class of machines. In most cases, the tolerance of the vibration is twice the tolerance of the real motion. In the fifth and sixth categories of machines, especially reciprocating engines, the structure and the relative influence of the inertial forces vary greatly, so the dynamic characteristics vary greatly. It is therefore difficult to classify them as in the first four categories. In the fifth category of machines it is easy to separate the multiple frequencies generated by the machine into relatively high frequencies corresponding to its rigid mounting system. For machines of this type, 20 to 30 mm/s or more rms vibration velocities may be used without causing any harm. In addition, if the coupling is effective, large displacements may occur at points at the same distance from the center of gravity. In the sixth category of machines, elastically mounted machines allow larger tolerances. Such machines have a diaphragm effect, and the forces transmitted from the left mounting point to the surrounding are very small. In this case, the vibration level measured next to the machine on the mounting system is lower than the vibration level measured when the machine is fixed on a relatively rigid support. 50 mm/s or more rms velocities may be measured on high-speed engines. Attached parts may have higher vibration velocities because they are often affected by resonance. When passing through its vibration zone, a velocity root mean square value of the order of 500 mm.s may appear in a short vibration. .5
GB 6075--85
Appendix B
Calculation of displacement amplitude from the root mean square value of velocity and a given frequency (reference number)
In many standards, the root mean square value of velocity is usually used in the frequency range of 10 to 1000 Hz: is the number, but in some cases it is important to know the displacement amplitude of the main frequency in the measured vibration spectrum. In addition, the displacement amplitude is also used as a parameter in some standards, so the root mean square value of velocity must be converted into peak displacement: only a single-frequency positive wave can be converted from vibration velocity to vibration displacement. If the extreme vibration velocity of the frequency is known, the peak displacement can be calculated by the following formula:
In the formula: is the displacement peak;
is the root mean square value of the vibration velocity with a frequency of: 02 is the frequency.
())
Example:
Given the intensity of vibration (RMS value of velocity) is 4mms, that is, the RMS value of the maximum vibration velocity in the frequency range of 10-1000! does not exceed 4mms. Spectrum analysis shows that the main frequency is 2.51z, and the RMS value of the vibration velocity is 2.8mms. Therefore, the peak value (calculated using the above relationship) is: (2.) -1).027 mm (or 271m)
3r= 0.225 (
The diagram of the above equation is given in the figure.
Note that the measurement speed is the basic parameter for measuring vibration intensity. It is very important. Generally speaking, it is inappropriate to estimate the vibration intensity value based on the displacement amplitude of the main frequency. Only when it is a single-frequency vibration, 1. When the root mean square value of the vibration velocity can be determined within the entire range of 10100011z (using the above equation B1), can the vibration intensity be calculated from the displacement amplitude of the main frequency. 136
GB6075—85
The change of peak displacement frequency at different root mean square values of velocity mo
Additional notes:
6075—85
This standard was drafted by the China National Institute of Metrology. The main drafter of this standard is Guo Yingchuan.2
18~ 28
28 45
GB 6075-—85
Appendix A
(Reference number)
In order to illustrate how the proposed classification method is used. The following examples of specific types of machines are given. This is only a simple example. Other classification methods can also be selected according to the specific situation under study. When the situation permits, the inferred values of the dynamic severity of specific types of machines should be given. Preliminary tests have shown that for most applications, the following classification method is appropriate. Class 1: Engines and machine parts that are integrated with the whole machine under normal operating conditions (production switches above 15kW are typical examples of this type of machine).
Class 2: Medium-sized machines without a dedicated basis (a typical example is a motor with an output power of 5-75kW), engines and machines rigidly mounted on a dedicated basis (below 300kW). Category 3: Large prime movers and other machines with rotating masses mounted on a very rigid (in the direction of vibration) heavy foundation.
Category 4: Large prime movers and other large machines with rotating masses (such as turbine sets, especially light turbine sets) mounted on a very rigid (in the direction of vibration) foundation. Category 5: Machines and mechanical drive systems with unbalanced inertial forces (the unbalanced inertial forces are caused by the reciprocating parts of the machine) mounted on a very rigid (in the direction of vibration) foundation. Category 6: Machines and mechanical drive systems with unbalanced inertia (caused by the reciprocating moving parts of the machine) mounted on a very rigid (in the direction of vibration) foundation. Machines with loose couplings and rotating masses, such as the shaft in a grinder. Machines whose variable unbalanced forces can work independently without connecting parts, such as coring machines, mobile screens used in processing, dynamic fatigue testing machines and vibration tables.
A large number of tests were carried out using the first four as examples, and their evaluations were obtained, as shown in the following table. The vibration severity is calculated in two levels, and it is recommended to be divided into four levels of A, B, (, I) for evaluating quality. When the maximum value measured at the important measuring points (especially the bearings) is within the corresponding range in the table below, the motor or machine can be evaluated according to the values in the table below. Vibration severity range and examples of their application to small machines (class 1), large machines (class 2), large machines (class 3) and turbine machines (class 4) Range of vibration severity Classification range Speed root mean square value at the limit of the range Examples of judging the quality of various machines Class 1 Class 4 Class 5 G36075-85 It is easy to distinguish the vibration levels in the horizontal and vertical directions measured on the first class of machines. In most cases, the tolerance of the vibration is twice the tolerance of the real motion. In the fifth and sixth categories of machines, especially reciprocating engines, the structure and the relative influence of the inertial forces vary greatly, so the dynamic characteristics vary greatly. It is therefore difficult to classify them as in the first four categories. In the fifth category of machines it is easy to separate the multiple frequencies generated by the machine into relatively high frequencies corresponding to its rigid mounting system. For machines of this type, 20 to 30 mm/s or more rms vibration velocities may be used without causing any harm. In addition, if the coupling is effective, large displacements may occur at points at the same distance from the center of gravity. In the sixth category of machines, elastically mounted machines allow larger tolerances. Such machines have a diaphragm effect, and the forces transmitted from the left mounting point to the surrounding are very small. In this case, the vibration level measured next to the machine on the mounting system is lower than the vibration level measured when the machine is fixed on a relatively rigid support. 50 mm/s or more rms velocities may be measured on high-speed engines. Attached parts may have higher vibration velocities because they are often affected by resonance. When passing through its vibration zone, a velocity root mean square value of the order of 500 mm.s may appear in a short vibration. .5
GB 6075--85
Appendix B
Calculation of displacement amplitude from the root mean square value of velocity and a given frequency (reference number)
In many standards, the root mean square value of velocity is usually used in the frequency range of 10 to 1000 Hz: is the number, but in some cases it is important to know the displacement amplitude of the main frequency in the measured vibration spectrum. In addition, the displacement amplitude is also used as a parameter in some standards, so the root mean square value of velocity must be converted into peak displacement: only a single-frequency positive wave can be converted from vibration velocity to vibration displacement. If the extreme vibration velocity of the frequency is known, the peak displacement can be calculated by the following formula:
In the formula: is the displacement peak;
is the root mean square value of the vibration velocity with a frequency of: 02 is the frequency.
())
Example:
Given the intensity of vibration (RMS value of velocity) is 4mms, that is, the RMS value of the maximum vibration velocity in the frequency range of 10-1000! does not exceed 4mms. Spectrum analysis shows that the main frequency is 2.51z, and the RMS value of the vibration velocity is 2.8mms. Therefore, the peak value (calculated using the above relationship) is: (2.) -1).027 mm (or 271m)
3r= 0.225 (
The diagram of the above equation is given in the figure.
Note that the measurement speed is the basic parameter for measuring vibration intensity. It is very important. Generally speaking, it is inappropriate to estimate the vibration intensity value based on the displacement amplitude of the main frequency. Only when it is a single-frequency vibration, 1. When the root mean square value of the vibration velocity can be determined within the entire range of 10100011z (using the above equation B1), can the vibration intensity be calculated from the displacement amplitude of the main frequency. 136
GB6075—85
The change of peak displacement frequency at different root mean square values of velocity mo
Additional notes:
6075—85
This standard was drafted by the China National Institute of Metrology. The main drafter of this standard is Guo Yingchuan.When the root mean square value of vibration velocity can be measured in the whole section of 10100011z (using equation B1 above), the vibration intensity can be calculated from the displacement value of the main frequency. 136
GB6075—85
The change of displacement peak frequency under different root mean square values of velocity mo
Additional remarks:
6075—85
This standard was drafted by the National Institute of Metrology. The main drafter of this standard is Guo Yingchuan.When the root mean square value of vibration velocity can be measured in the whole section of 10100011z (using equation B1 above), the vibration intensity can be calculated from the displacement value of the main frequency. 136
GB6075—85
The change of displacement peak frequency under different root mean square values of velocity mo
Additional remarks:
6075—85
This standard was drafted by the National Institute of Metrology. The main drafter of this standard is Guo Yingchuan.
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