JB/T 7920-1995 Inspection method for the circumference of thin-walled bearings of sliding bearings JB/T7920-1995 Standard download decompression password: www.bzxz.net

1 Introduction
National Standard of the People's Republic of China
Plain bearings-Methods of dimensional control--Peripheral length checking of thin-walled half bearings This standard specifies the inspection method, equipment and measuring tools for the circumference of thin-walled bearings. UDC621.822.5
GB6415-86
Thin-walled bearings are flexible and are not cylindrical in a free state. Therefore, the circumference of the bearing can only be measured with special measuring equipment under a forced load.
It is also possible not to use the measuring equipment specified in this standard. However, the measured value should be within the tolerance range of repeatability, reproducibility and comparability specified in this standard.
This standard is applicable to the provisions of GB3162-82 "Dimensions, structural elements and tolerances of thin-walled bearings for sliding bearings". This standard is equivalent to ISO6524-83 "Inspection method for the circumference of thin-walled bearings for sliding bearings". 2 Nouns, terms and symbols
S or S, +S2-
F=F, =F2
Protrusion (see Figure 1), mm;
Test load, N;
Correction value, mm;
Circumference, mm,
Test die hole diameter, mm;
Test distance from the bottom of the die hole to the reference plane, mm; Test die width (rib bearing structure), mm; -Test die width (non-rib bearing structure), mm; B2—
Test die width, mm;
-Test die chamfer (non-rib bearing structure), mm; K-
Kz-Test die chamfer (rib bearing structure), mmsDbs—Bearing shell outer diameter, mm;
Bearing shell total wall thickness, mm;
-None Width of flange bearing, mm;
- flange spacing of flange bearing, mm
h- fillet radius between the back of flange bearing and the flange, mm; des-outer diameter of calibration pad, mm;
-width of calibration pad, mm;
wall thickness of calibration pad, mm;
-compensation for the difference in elastic deformation between method A and method B during loading, mm; 8
coefficient of deviation calculated during loading, mm/N; GB6415-86
special angle notes are as follows:
Note: ① The protrusion is the dimension (SN) that exceeds the specified circumference of the inspection die hole when the bearing is installed in the inspection die with a diameter of Dcb under the action of the inspection load F. ② The meaning of the special angle note, bs-
Inspected bearing: cb-
Test mold; cbs-
Batch test mold; Cs-
Calibration bearing. bZxz.net
3. The "M" or "1h" angle note can be used after the symbol to indicate the actual measurement value or theoretical value respectively; appropriate angle notes can also be added to distinguish the measuring tools used.
Figure 1 Height
3 Inspection method
3.1 Inspection method A
The inspection load F is directly applied to one mating surface of the bearing through a probe with a rotating pressure plate, while the other mating surface is in contact with a fixed pressure plate (see Figure 2).
3.2 Inspection method B
The inspection loads F and F are respectively applied to the two mating surfaces of the bearing through two pressure plates with probes (see Figure 3). Micrometer
Fixed platen
Moving probe
Reference surface
Rotating platen
Testing mold
Micrometer
Rotating platen
GB6415-86
SNI+SN2=height
Micrometer
Reference surface
Fixed platen
Testing mold
Figure 3 Schematic diagram of the principle of test method B
Note: In test method A, the required reaction force is generated by the fixed platen; in test method B, it is directly applied by the measuring device through the two platens. For example: method AF=6000N,
method B
F,=6000N
Fz=6000N.
Choice of test method and marking
4.1 Choice of test method
Select method A or method B from Table 1 according to the size of the bearing to be tested. Bearings of any size may be tested by either of the two methods, subject to agreement between the manufacturer and the user. In this case, the relationship between the heights obtained by the two methods is as follows, where the correction value 8 is the actual compensation for the difference in elastic deformation between method A and method B when loading the mating surfaces. S=S,+S+
Recommended test method
(1)
GB.641586
The marking example for testing thin-walled bearings with an outer diameter Dbs equal to 340 mm by method A is: Method GB6415—A-340
Measuring equipment
Figures 4 and 5 show typical measuring equipment for measuring heights by methods A and B. Pressure gauge
Micrometer
Rotating platen
Testing mould
Moving measuring head
Pressure regulating valve
Hydraulic cylinder
Figure 4 Typical single-column measuring equipment for test method A Moving measuring head
Full micrometer
Weight fixed platen
GB6415-86
Pressure gauge
Hydraulic cylinder
Rotating platen
Testing mould
Figure 5 Typical double-column measuring equipment for test method B Note: Figures 4 and 5 are hydraulic measuring equipment. Pneumatic or mechanical measuring equipment can also be used. Requirements for measuring equipment
6.1 Tolerance of test load
The tolerance of test load shall be as specified in Table 2.
Deviation of F
GB6415--86
The probe must be accurately guided and moved vertically relative to the reference plane of the inspection mold. The radial parallelism tolerance between the measuring plane of the rotating pressure plate in the probe and the reference plane of the inspection mold is not more than 0.04mm per 100mm. 6.4 Accuracy of the measuring plane of the rotating pressure plate
The accuracy of the measuring plane of the rotating pressure plate shall be as specified in Table 3. Table 3
6.5 Accuracy of micrometer
Total deviation: ±0.6μm;
Scale value: 1μm.
Measuring tool for determining the reference
Measure with the following equipment according to the specific situation: calibration inspection mold (reference measurement)
Batch inspection mold (for batch control); calibration tile (for batch control).
Surface roughness R,
Flatness tolerance
These gages can be measured in three ways, with micrometer positioning and checking on the reference surface. 7.1 Calibration test die
The calibration test die serves as the reference for the batch test die. 7.2 Batch test die
The circumference of the hole of this type of test die is obtained by comparison with the calibration test die. The batch test die is used for batch control without calibration pads.
7.3 Batch test die with calibration pad
The circumference of the test die hole is obtained by calibration pads, which are obtained from the calibration test die. This combination of gages is suitable for batch control. NOTE: For batch control, the test die can also be used with calibration pads, but this combination of gages is not within the scope of this standard. Requirements for the test die
The test die is shown in Figure 6. The measuring part of the test die is a hole with a diameter of Dcb and a height of Hb. The material of the test die must be hardened steel.
抢必播
和CF或
的标区
GB6415-86
CFe和CFch的引用面
K,或K，
Figure 6 Inspection module
Note: The values ​​of α1 and 42 in Table 6 and Table 7 are recommended values. ②For bearings without flanges:
B, can correspond to B or equal to Lmx+3Kimax
where K1mxx=0.4mm.
③For bearings with flanges.
B, see Table 6
K2=hmax+0.5mm
D. Limit deviation
Surface roughness R of the test die hole
Hc6 Limit deviation
K, or K
Surface roughness R of the reference surface.
GB6415--86
8.1.1.1 The typical values ​​of the geometric tolerances t to t7 of the calibration test die are 50% of the values ​​listed in Tables 6 and 7. 8.1.1.2 The values ​​of surface roughness a and a2 are as specified in Tables 6 and 7. 8.1.1.3B, B,and B3, see Tables 6 and 7. 8.1.2 Measurement accuracy of equipment for measuring DcbM and HcbM The measurement of DcbM and HcbM must be carried out using measuring equipment with the following reading accuracy: ±0.0005mm when Dcb<160mm; ±0.001mm when
Dcb>160mm.
These values ​​are necessary for calculating the correction value CFcb (see 10.1) from the circumference. x=+2(HebM
PLμ= DcbM×-
8.1.3 Wear limit
The calibration test die is not allowed to have wear.
8.2 Batch control gauge
8.2.1 Batch test die
Since the circumference of this test die is obtained by comparison with the calibration test die, D. and Hc are allowed to have larger tolerances. 8.2.1.1 Manufacturing limit
The manufacturing limits and technical requirements of batch test dies are specified in Tables 5 to 7. Table 5
D. Limit deviation
Surface roughness R of the test die hole.
He Limit deviation
Surface roughness R of the reference surface. | |tt||Bearing without flange
Wear limit
GB641586
Bearing with flange
Zmia-0.05
Zmia-0.15
Zmin-0.02
Zmin-0.15
Surface roughness R,
Surface roughness R
Parallelism tolerance
The allowable wear limit of batch inspection mold is equal to the difference between the original correction value specified in Table 8 and the correction value under wear conditions. Table 8
ICFcbs New-CFebs Wear
8.2.2.1 Manufacturing limit
GB 6415-86
The manufacturing limits and technical requirements of batch inspection dies with correction pads are the same as those of batch inspection dies, see Table 5 and Table 7.8.2.2.2 Wear limits
The allowable wear limits of batch inspection dies with correction pads are the same as those of batch inspection dies, see Table 8. Requirements for calibration pads
The calibration pads are shown in Figure 7. The basic dimensions of the calibration pads must be consistent with the basic dimensions of the bearing pads to be inspected. The calibration pads installed in the inspection mold should have the same characteristics as the bearing pads.
Note: This calibration pad is also suitable for inspecting flange bearing pads. Calibration pads with an outer diameter of less than 160 mm should be made of hardened steel (minimum hardness HRC55). In order for one calibration pad to be used for a group of bearing pads with a diameter of less than 1.5 mm, Scs should be the total wall thickness e of the bearing pads to be inspected plus 0.125 mm. a4*
9.1 Manufacturing limits Limit
dcsM, F and CFes marked
Figure 7 Calibration pad
The manufacturing limits and technical requirements of the calibration pad shall be in accordance with the provisions of Tables 9 and 10. Table 9
Ls Limit deviation
Surface roughness R
Ss Limit deviation
Parallelism tolerance t8
Surface roughness R.
Flatness tolerance t9
9.2 Wear limit
GB6415-—86
The difference between the original correction value and the correction value under wear conditions is not allowed to exceed the provisions of Table 11. Table 11
Correction value
10.1 Reference measuring tool
The correction value (CFsb) of the calibration test mold is: CFh=PL
The measured circumference of the calibration test mold hole is calculated by the following formula: PLu= DcbM ×
The theoretical circumference of the calibration inspection die hole is calculated by the following formula: to
+2(HebM
!CFes新-CFes报|
（3）
（4）
Other values ​​and calculation methods to be considered are given in Appendix A (Test Method A) (Supplement) and Appendix B (Test Method B) (Supplement).
The reference of the correction value (CFc) is the reference surface of the calibration inspection die. 10.2 Batch control gauge
10.2.1 Correction value (CFcbs) of batch inspection die The correction value CFcbs is determined by the difference between the bearing height (SM) measured by the calibration inspection die and the bearing height (Sns) measured by the batch inspection die under the same inspection conditions [see Appendix C (Supplement). CFcbs=SnM
When installing the micrometer, only the correction value of the batch inspection die (CFcbs) should be considered. The reference of the correction value CFcbs is the reference surface of the batch inspection die. 10.2.2 Correction value of the batch inspection die with calibration pad. (5)
When measuring the wear limit of the batch inspection die, the correction value of the batch inspection die should not be considered. When adjusting the micrometer, only the correction value of the calibration pad (CFcs) should be considered.
Correction value of the calibration padCFes new-CFes report|
(3)
(4)
Other values ​​and calculation methods to be considered are given in Appendix A (Test Method A) (Supplement) and Appendix B (Test Method B) (Supplement).
The reference of the correction value (CFc) is the reference surface of the calibration test die. 10.2 Batch control gauge
10.2.1 Correction value (CFcbs) of the batch test die The correction value CFcbs is determined by the difference between the bearing height (SM) measured by the calibration test die and the bearing height (Sns) measured by the batch test die under the same test conditions [see Appendix C (Supplement). CFcbs = SnM
When the micrometer is installed, only the correction value (CFcbs) of the batch test die should be considered. The reference of the correction value CFcbs is the reference surface of the batch test die. 10.2.2 Correction value of the batch test die with calibration pads (5)
When measuring the wear limit of the batch inspection die, the correction value of the batch inspection die should not be taken into account. When adjusting the micrometer, only the correction value of the calibration shoe (CFcs) should be taken into account.
Correction value of the calibration shoeCFes new-CFes report|
(3)
(4)
Other values ​​and calculation methods to be considered are given in Appendix A (Test Method A) (Supplement) and Appendix B (Test Method B) (Supplement).
The reference of the correction value (CFc) is the reference surface of the calibration test die. 10.2 Batch control gauge
10.2.1 Correction value (CFcbs) of the batch test die The correction value CFcbs is determined by the difference between the bearing height (SM) measured by the calibration test die and the bearing height (Sns) measured by the batch test die under the same test conditions [see Appendix C (Supplement). CFcbs = SnM
When the micrometer is installed, only the correction value (CFcbs) of the batch test die should be considered. The reference of the correction value CFcbs is the reference surface of the batch test die. 10.2.2 Correction value of the batch test die with calibration pads (5)
When measuring the wear limit of the batch inspection die, the correction value of the batch inspection die should not be taken into account. Only the correction value of the calibration shoe (CFcs) should be taken into account when adjusting the micrometer.
Correction value of the calibration shoe
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