Some standard content:
UDC:62-57B.22
National Standard of the People's Republic of China
GB/T.15141--94
Test method for friction element of wet clutch1994-07-19Published
National Technical Supervision Bureau
1995-04-01Implementation
National Standard of the People's Republic of China
Friction element of wet clutch
Test method
Test method for frietion element of wet clutch 1 Subject content and scope of application
This standard specifies the test method for friction elements of clutches. This standard is applicable to clutches of both types.
2 Reference standards
G31111 Industrial lubricant viscosity classification
GE10042 Commercial clutch terminology
3 Terms and symbols
In addition to adopting GB10042, the technical community also adopts the following terms: 3.1 Allowable temperature on friction surface The maximum temperature allowed to be borne by the friction surface under the premise of ensuring the effective operation of the friction pair. 3.2 Normal force F Noral pressure
The normal force borne on the friction surface of the friction pair. 4 Test device
GB/ 15141-94
4.1 The test device consists of a power mechanical system, a control system, a data acquisition and processing system, etc. Schematic diagram of test bench 1. Figure 1 Schematic diagram of test bench
1 Comparator 2 Inertial flywheel 3 Clutch 4 Carrier wheel 5 Actuator 6 Torque sensor 7 Pressure sensor 8 Speed sensor National Technical Supervision Approved on July 19, 1994 and implemented on April 1, 1995
GB/T1514194
4.2 The test bench should be able to test and record data such as slip E, friction torque M, normal pressure F, sliding time t, temperature T, etc. The instrument accuracy should not be less than ±1.
5 Test piece
5.1 Composition of test piece
The test piece includes friction plate and mating plate. The structure and surface condition of the test piece should be determined according to the use requirements. 5.2 Running-in of test piece
5.2.1 Before the performance test, the test piece should be run-in under the condition that does not cause surface burning. When the contact area reaches 80% of the apparent area, the running-in is completed.
5.2.2 The relative position of the test piece during the test should be the same as during the running-in. 5.3 Test thickness
Measure the original thickness of 8 points of the test piece with a micrometer according to Figure 2, accurate to 0.001mm, and mark the non-friction area, and calculate the arithmetic mean of the thickness.
6 Determination of friction coefficient
6.1 Test conditions shall be as specified in Table 1, and appropriate adjustments may be made when necessary. Table 1 Test strips Test equipment Kinetic energy Et, Engagement frequency, min/min Engagement times Pressure rise time + Sequence time 513 Apparent pressure p, Pa 0.5 j) - 23 3.23 . A × 10 m3 1.0 ± 0.1 General data Adjustment Cooling type Cooling oil separation, m/ms Method: 1) is the rotation speed of the inching part kkn, 2) is the speed ra: 3) 2 pairs of source rubbing times: GB/T 15141--94 Continued 1 N33 (G3 3141-82)
4)4, for the decay surface, mn,
6.2 According to the requirements of Table 1, adjust the speed of the loaded flywheel of the test device, and
6.3 Determine the slip speed, friction torque M, positive pressure F, and sliding friction of the 25th, 50th, 75th, and 10th times of the elastic joint.
6.4 The sliding friction coefficient is calculated according to formula (1) (r)
F(c) -m -2
In the formula, μ(t)—…+dynamic friction coefficient at time t(r)—friction reverse force at time -r, Nm
F(t)—.-E combined positive force at the moment, N
r—average friction radius, m
—friction scraping effect.
-+(1)
6.5 The semi-average sliding friction coefficient of the first joint is calculated according to formula 2), and the average running friction coefficient of the friction element is calculated according to the common center (3). A
= (02s + g + s + /1
Wherein: Lake\: the average running friction coefficient of the first joint; a(t).--the sliding barrier coefficient at time 1:
average sliding friction coefficient;
4---the average sliding barrier coefficient of the 25th joint: a-the average constant sliding barrier coefficient of the 50th joint; M4---the average sliding contact coefficient of the 75th joint: the average sliding friction coefficient of the 100th joint. + (2)
6-6 After completing the 25th, 50th, 75th, and 10th joints in Article 6.3, remove the positive force, and then add the positive force again, and measure the sliding speed of the friction piece at the average radius as ~ m/s when the friction torque and positive force are . 6.7 According to formula (4>, calculate the static friction coefficient after the first engagement. a1
Wherein: ||tt| ... 1)/4
Static friction coefficient of the 25th engagement
Static friction coefficient of the 50th engagement;
Static friction coefficient of the 75th engagement:
Static friction coefficient of the 100th engagement.
7 Determination of wear rate
7.1 Test conditions shall be in accordance with the provisions of method 1 in Article 6.1. 7.2 Operate the test device and engage 3000 times. 7.3 After the friction element has cooled to room temperature, measure the thickness of the original 8 marked points of the test piece and calculate the arithmetic mean of the thickness. 7.4 Calculate the wear rate according to formula (6).
ha -- h,
wherein. K·wear rate, m]·
-average thickness of the test piece before the wear test. nm; hr
average thickness of the test piece during the wear test, mm: 3000E
number of wear surfaces of a test piece, single-sided wear 1=1; double-sided wear i—2, average sliding work of a joint process: calculation formula see Appendix A (reference). 8 Determination of allowable thermal load
The test conditions of the allowable thermal load shall be in accordance with the provisions of method 1 or method 2 in Article 6.1. 8.1 The measurement shall be carried out in accordance with the provisions of method 1.
8 1.1 The measurement items are sliding work, sliding friction rate, thermal load and friction surface temperature. (5)
8. 1. 2 Measure and record the slip angular velocity n, friction torque M, normal pressure F, sliding time t, at the 25th, 51st, 75th, and 100th joints. and the temperature of the friction surface (measure the temperature at the average radius 0.2~0.3mm away from the friction space using an armored thermoelectric regulator with an outer diameter of less than 2mm). 8.1.3 According to formula (7), change the speed or increase the flywheel inertia to increase the kinetic energy of the test device, and repeat the above test until the friction cutting fails. E 1. 2 +7 . A. × 10
Where: E is the kinetic energy of the test device in the first test, J;
Z is the number of friction pairs, H;
A is the surface area of the device, m.
8.1.4 Calculate the sliding friction power, sliding friction rate and heat load. The calculation formula is shown in Appendix A. (7)
8-1.5 Take the average value of the heat load of the 25th, 50th, 75th and 100th engagement process before the friction failure as the allowable heat load value of the clutch friction element: 21. The calculation formula is shown in Appendix A8.1.6 Take the average value of the maximum temperature of the friction surface in the 25th, 50th, 75th and 100th engagement process before the friction brush fails as the allowable temperature of the friction surface [T].
8.2 Measure according to the provisions of Formula 2
8.2-1 The measurement items are allowable pressure, sliding barrier power, sliding storage power, heat load and friction surface temperature. 8.2.2 Increase the apparent pressure step by step by 0.3MPa, and measure and record the items in the same way as in 8.1.2.8.2.3 If the friction element has not failed when the energy level reaches the apparent value allowed by the test bench, then increase the kinetic energy of the test device according to formula (7) and repeat the above test until the friction pair fails.
GR/T 15141-94
8-2.4 According to the method in 8.1.5, take the allowable heat load value [g] of the friction reducing element. 8.2.5 According to the method in 8.1.6, take the allowable temperature T7 of the friction melting surface. 8.2.6 Take the apparent H intensity of the working condition before the friction melting failure as the allowable pressure Lp1 of the friction plate. 8.3 Determination of friction pair failurebZxz.net
One of the following phenomena is regarded as a friction pair failure. a
Abnormal changes in the friction torque curve:
Plastic deformation or pitting of the friction layer:
Warping deformation exceeds the allowable range
9Test report
Write a test report based on the test results. The test report should include the following contents: test name, test purpose;
Test piece geometry, size, accuracy, material, quantity, manufacturer, test equipment, test method, test conditions, test items::
Test results and analysis:
Test conclusion
Test period, test personnel.
A1For the calculation of sliding friction work, see formula (A1).
In the formula: E—
Sliding work J/Ⅲ\;
Sliding time, 3
GB/T 15141—94
Appendix A
Sliding work, sliding power and heat load calculation formula (reference)
(t)+wtt)-di
-r moment friction torque, Nm
a(r)——- moment slip angular velocity, rad/stZ…Friction number,
A, apparent area, m
Calculation formula for instantaneous sliding power (A2). A2
Where: A(e)-·Instantaneous storage power, W/m\M(t)—Friction torque at time t, Nm
u(t)——Slip angular velocity at time 1, rad/stz——Number of friction pairs at time t
A, apparent area, m°.
For the calculation of the quasi-3 thermal load value, see formula (A3), 7+
(t) -wtt)
Where: 9—
Thermal load position:
Slip work, J/m2;
Instantaneous friction power, W/m.
A4For the calculation of the permissible thermal load, see formula (A4). [n. - E+A(t).
The maximum instantaneous friction power of the previous peak effect, W/mW: A
[9.——Permissible heat load;
E·friction power. J/m.
（A3)
Additional remarks:
This standard is proposed by China State Shipbuilding Corporation. GB/T 15141—94
This standard is submitted by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry of the People's Republic of China. This standard was drafted by the Seventh Institute of the Seventh Research Institute of China State Shipbuilding Corporation. The main drafters of this standard are Zhang Xiehu and Gao Xiaomin.
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