CN101922906A - Method of measuring axial clearance and preload clearance of back-to-back angular contact ball bearings - Google Patents

Abstract

A method for measuring the axial clearance or preload clearance of back-to-back angular contact ball bearings is to first manufacture an outer ring spacer (4), a washer (1), an inner diameter load block (7) and a measurement system. The inner ring (2) of bearing I is placed on the washer, bearing I and bearing II are placed back to back in the outer ring spacer, and the inner diameter load block is placed in the inner ring (6) of bearing II. To calibrate the measuring instrument, extend the ends of two equal-length levers with right-angle measuring heads through the two notches of the inner ring spacer. During measurement, the inner diameter load block of the counterweight exerts an axial load on bearing I and bearing II, and the two right-angle probes are respectively aligned with the center points A and B of bearing I and bearing II, A-B=δ, if δ is negative The value indicates that bearing I and bearing II have axial clearance, and if δ is a positive value, it indicates that bearing I and bearing II have preload clearance. The invention has the characteristics of simple operation, the measurement results do not need complicated conversion, the A value and the B value are intuitive and readable, and there is no conversion and accumulation error.

Description

Method of measuring axial clearance and preload clearance of back-to-back angular contact ball bearings

technical field

The invention belongs to the technical field of bearing measurement, and in particular relates to a method for measuring axial clearance and preload clearance of back-to-back angular contact ball bearings.

Background technique

Angular contact ball bearings have supporting radial clearance at the time of design. Only after the angular contact ball bearings are paired and installed can they have axial clearance or preload clearance. The size of the axial clearance or preload clearance depends on The adjustment amount of the other paired angular contact ball bearing.

Angular contact ball bearings have different subtle structural changes. According to the user's requirements for the use of angular contact ball bearings, axial clearance (or pre-clearance) or preload clearance can be provided for back-to-back (DB pairing type) (or preload), back-to-back means that the large end faces of the paired angular contact ball bearings correspond to each other, and the axial clearance and preload clearance of the back-to-back paired angular contact ball bearings are shown in Figure 1 and Figure 2.

Figure 1 shows the axial clearance generated when the back-to-back angular contact ball bearings are displaced in the axial direction, and the axial clearance is specified as a positive value.

Figure 2 shows the preload clearance generated when angular contact ball bearings are back-to-back paired to achieve preload in the axial direction. The preload clearance is specified as a negative value or zero.

The existing measurement methods for axial clearance or preload clearance of back-to-back angular contact ball bearings are roughly as follows:

Use a high-precision angular contact ball bearing protrusion measuring instrument to measure the protrusion of a single set of angular contact ball bearings, and grind the protrusion, and then convert it into back-to-back angular contact according to the protrusion value of the paired back-to-back angular contact ball bearings Axial clearance or preload clearance of a ball bearing. The whole process uses an indirect method for measurement and conversion, and its operation procedures are complex, cumbersome and inefficient, and prone to cumulative errors.

Contents of the invention

In order to better meet the measurement requirements of back-to-back angular contact ball bearing axial clearance or preload clearance, the present invention proposes a measurement method for back-to-back angular contact ball bearing axial clearance or preload clearance. Accurate and direct measurement of axial clearance or preload clearance of back-to-back angular contact ball bearings.

In order to realize the above-mentioned purpose of the invention, the present invention adopts following technical scheme:

The bearing I and the bearing II mentioned in the present invention both refer to the tested angular contact ball bearing, and the paired bearing I and bearing II have the same type and structure size.

The method for measuring the axial clearance or preload clearance of the back-to-back angular contact ball bearings firstly makes an outer ring spacer, a gasket, an inner diameter load block and a measuring system, and the inner diameter of the outer ring spacer is the same as that of the bearing I or The inner diameter of the outer ring of the bearing II is equal, the outer diameter of the outer ring spacer is equal to the outer diameter of the outer ring of the bearing I or bearing II, and there are two symmetrical notch grooves in the radial direction of the outer ring spacer; the outer ring of the washer diameter is equal to the outer diameter of the inner ring of bearing I or bearing II, and the inner diameter of the gasket is equal to the inner diameter of the inner ring of bearing I or bearing II; the inner diameter load block has a boss shape, and the maximum outer diameter of the inner diameter load block is the same as that of bearing II The outer diameter of the inner ring is equal, the outer diameter of the boss of the inner diameter load block ≤ the inner diameter of the inner ring of the bearing II, the width of the boss of the inner diameter load block ≤ half of the width of the bearing II, and the inner diameter load block has according to the type of bearing I or bearing II Different counterweights; the measurement system consists of two opposite hinge points, two equal-length levers and a measuring instrument, the midpoints of the two equal-length levers are respectively fixed on the respective hinge points, and the two equal-length levers are respectively fixed on the respective hinge points. One end of the long lever is provided with two right-angle probes in opposite directions, and the other ends of the two equal-length levers are connected to the measuring instrument. The distance from the right-angle probe to the hinge point is equal to the distance from the hinge point to the connecting end of the measuring instrument, so that Two equal-length levers form two equal-arm levers through the hinge fulcrum. The distance between the two equal-length levers is based on the two symmetrical notches that are conveniently placed in the spacer of the outer ring; before measurement, place the gasket flat on the measurement platform Put the inner ring of bearing I on the washer, then place the outer ring spacer on the outer ring of bearing I, then put the outer ring of bearing II on the outer ring spacer, pay attention to the large end surface of the outer ring of bearing I and The large end face of the outer ring of the bearing II passes back to back through the outer ring spacer, and finally put the inner diameter load block of the counterweight in the inner ring of the bearing II; adjust the measuring system so that the two equal-length levers are parallel to each other, and the pointer of the measuring instrument at this time Calibrate to zero, extend the ends of the two equal-length levers with right-angle probes into the outer ring spacer through the two notches of the outer ring spacer; when measuring, the inner diameter load block of the counterweight is on the bearing I and the bearing II applies an axial load, and the two right-angle probes are first aligned with the center point A of the radial width of the inner ring of bearing I and bearing II. At this time, the center point A will display an A value through the measuring instrument, and then move two right-angle The measuring head is aligned with the center point B of the radial width of the outer ring of bearing I and bearing II, and a B value is displayed by the measuring instrument at the center point B, and the difference between the A value and the B value is calculated, if the A value minus the B value When it is equal to δ and δ is a negative value, it indicates that bearing I and bearing II are paired with pre-clearance, that is, the axial clearance of bearing I and bearing II is δ; if A value minus B value is equal to δ and δ is a positive value , indicating that bearing I and bearing II are a preload pair, that is, the preload clearance of bearing I and bearing II is δ, and the axial direction of bearing I and bearing II should be preloaded when they are paired; The end face of the II marks the measurement and the counterweight of the inner diameter load block.

Owing to adopting above-mentioned technical scheme, the present invention has following characteristics:

1. In the present invention, the back-to-back angular contact ball bearings to be measured adopt one-time clamping and positioning, which eliminates the influence of positioning errors on the measurement results and ensures the measurement accuracy.

2. The present invention is a direct measurement method with the characteristics of simple operation, the measurement results do not need complex conversion, A value and B value are intuitive and readable, and there is no conversion and cumulative error.

3. The measurement method of the present invention can also be used for the measurement of paired deep groove ball bearings.

Description of drawings

Figure 1 is a schematic diagram of the axial clearance of angular contact ball bearings in back-to-back pairs;

Figure 2 is a schematic diagram of the preload clearance of angular contact ball bearings in back-to-back pairs;

Fig. 3 is a schematic diagram of the installation position of the present invention for back-to-back angular contact ball bearing measurement.

In Figure 3: 1-washer; 2-inner ring of bearing I; 3-outer ring of bearing I; 4-outer ring spacer; 5-outer ring of bearing II; 6-inner ring of bearing II; 7- Inside diameter load block.

Detailed ways

In conjunction with Fig. 3, the present invention will make the outer ring spacer 4, the washer 1, the inner diameter load block 7 and a measuring system before the measurement.

The inner diameter of the outer ring spacer 4 is equal to the inner diameter of the outer ring of the bearing I or bearing II, and the outer diameter of the outer ring spacer 4 is equal to the outer diameter of the outer ring of the bearing I or bearing II, and the radial opening of the outer ring spacer 4 There are two symmetrical notch slots. The outer ring spacer 4 must undergo heat treatment, and the hardness after heat treatment can reach HRC60-65. Secondly, the outer ring spacer 4 needs to be precisely ground to ensure that the parallel difference between the two ends of the outer ring spacer 4 is not greater than 1 μm. Finally, the outer ring spacer The notch of sleeve 4 should be able to pass through the two parallel right-angle probes in the measuring system smoothly.

The outer diameter of washer 1 is equal to the outer diameter of the inner ring of bearing I or bearing II, and the inner diameter of washer 1 is equal to the inner diameter of the inner ring of bearing I or bearing II. The washer 1 plays the role of measuring and positioning. The washer 1 must be heat-treated, and the hardness after heat treatment can reach HRC60-65. Secondly, the washer 1 needs to be precisely ground to ensure that the parallel difference between the two ends of the washer 1 is not greater than 1 μm.

The inner diameter load block 7 has a boss shape, the maximum outer diameter of the inner diameter load block 7 is equal to the outer diameter of the inner ring of the bearing II, the outer diameter of the boss of the inner diameter load block 7 ≤ the inner diameter of the inner ring of the bearing II, and the inner diameter load block 7 is convex The width of the platform is less than half of the width of the bearing II, and the inner diameter load block has different counterweights according to the type of bearing I or bearing II, for example: the outer diameter of the bearing I or bearing II is less than 50mm, and the total weight of the inner diameter load block 7 is 24.5N; the outer diameter is between 50-120mm, and the total weight of the inner diameter load block 7 is 49N; the outer diameter is between 120-200mm, and the total weight of the inner diameter load block 7 is 98N; Its inner diameter load block 7 total weight is 196N. The counterweight mode of the above-mentioned inner diameter load block does not have a standard effect, and the counterweight of the inner diameter load block is preferably determined according to the needs of users, because different counterweights are different to the measurement results, and the counterweight mode of the inner diameter load block in the present invention It is for reference only, but it does not affect the specific implementation of the present invention.

The measurement system has been shown in Figure 3. The measurement system is composed of two hinge points facing each other, two equal-length levers and a measuring instrument. The midpoints of the two equal-length levers are respectively fixed on the respective hinge points. One end of the equal-length lever is provided with two right-angle measuring heads in opposite directions, and the other ends of the two equal-length levers are connected to the measuring instrument. The distance from the right-angle measuring head to the hinge point is equal to the distance from the hinge point to the connecting end of the measuring instrument, so that The two equal-length levers form two equal-arm levers through the hinge fulcrum, and the distance between the two equal-length levers is as the criterion for the two symmetrical notch grooves conveniently put into the outer ring spacer. The relatively set hinge fulcrum can be realized by the inner groove of the U-shaped block. The width of the inner groove of the U-shaped block can match the width of the outer ring spacer 4, so holding the U-shaped block is equivalent to holding the measurement system, so The measuring system can be randomly inserted and measured according to the position and direction of the notch groove of the outer ring spacer 4 .

Before the measurement, put the washer 1 flat on the measuring platform, put the inner ring 2 of the bearing I on the washer 1, then place the outer ring spacer 4 on the outer ring 3 of the bearing I, and then place the outer ring 5 of the bearing II Put it on the outer ring spacer 4, pay attention that the large end face of the outer ring of bearing I and the large end face of the outer ring of bearing II should be back to back through the outer ring spacer, and finally put the inner diameter load block 7 of the counterweight in the inner ring 6 of bearing II . In this process, the bearing I and the bearing II adopt a clamping and positioning method, which can eliminate the influence of the positioning error on the measurement result and ensure the measurement accuracy.

Adjust the measurement system so that the two equal-length levers are parallel to each other. At this time, the pointer of the measuring instrument is calibrated to zero, and the ends of the two equal-length levers with right-angle measuring heads are extended to the outside through the two notches of the outer ring spacer 4. Inside the ring spacer. The two equal-length levers are required to have good rigidity, and the length difference between the two equal-length levers should not be greater than ±0.1mm, otherwise it will easily cause systematic measurement errors of the measurement system. In addition, if the ends of the two right-angle probes are worn, the probes should be replaced in time.

During the measurement, the inner diameter load block 7 of the counterweight exerts an axial load on the bearing I and the bearing II, and the two right-angle probes are first aligned with the center point A of the radial width of the inner ring of the bearing I and the bearing II. At this time, the center point A A value of A is displayed by the measuring instrument, and then the two right-angle probes are moved to align with the center point B of the radial width of the outer ring of bearing I and bearing II, and a value of B is displayed by the measuring instrument at the center point B, and the calculation The difference between the A value and the B value.

If the A value minus the B value is equal to δ and δ is a negative value, it indicates that the bearing I and the bearing II are paired with pre-clearance, that is, the axial clearance of the bearing I and the bearing II is δ.

If the A value minus the B value is equal to δ and δ is a positive value (including δ=0), it indicates that the bearing I and the bearing II are preloaded, that is, the preload clearance of the bearing I and the bearing II is δ, and the bearing I and the bearing II are preloaded. When the bearing II is used as a pair, its axial direction should be preloaded.

It should be noted that in the measurement system, since two equal-length levers are respectively connected and supported by two hinge points to form two equal-arm levers, according to the principle of equal-arm levers, the measured values calculated at points A and B are δ is either a positive value or a negative value, so that the corresponding measuring instruments on the other ends of the two equal-arm levers are negative or positive. It can be seen from this that the above measurement process is a direct measurement method with the characteristics of simple operation, the measurement results do not need complicated conversion, the A value and B value are intuitive and readable, and there is no conversion and cumulative error.

After the measurement is completed, mark the measurement results and the weight of the inner diameter load block on the end faces of bearing I and bearing II for reference during pairing installation.

The measurement method of the invention can also be used for the measurement of paired deep groove ball bearings.

Claims (1)

1. A method for measuring the axial clearance or preload clearance of back-to-back angular contact ball bearings, which is characterized in that the outer ring spacer (4), the washer (1), the inner diameter load block (7) and a measuring system, the inner diameter of the outer ring spacer (4) is equal to the inner diameter of the outer ring of bearing I or bearing II, the outer diameter of the outer ring spacer (4) is equal to the outer diameter of the outer ring of bearing I or bearing II, and There are two symmetrical notch grooves in the radial direction of the ring spacer (4); the outer diameter of the washer (1) is equal to the outer diameter of the inner ring of the bearing I or bearing II, and the inner diameter of the washer (1) is the same as that of the bearing I or bearing II. The inner diameter of the inner ring of the bearing II is equal; the inner diameter load block (7) has a boss shape, the maximum outer diameter of the inner diameter load block (7) is equal to the outer diameter of the inner ring (2) of the bearing II, and the inner diameter load block (7) The outer diameter of the boss ≤ the inner diameter of the inner ring (6) of the bearing II, the width of the boss of the inner diameter load block (7) ≤ half of the width of the bearing II, and the inner diameter load block (7) has Different counterweights; the measurement system consists of two opposite hinge points, two equal-length levers and a measuring instrument, the midpoints of the two equal-length levers are respectively fixed on the respective hinge points, and the two equal-length levers are respectively fixed on the respective hinge points. One end of the long lever is provided with two right-angle probes in opposite directions, and the other ends of the two equal-length levers are connected to the measuring instrument. The distance from the right-angle probe to the hinge point is equal to the distance from the hinge point to the connecting end of the measuring instrument, so that Two equal-length levers form two equal-arm levers through the hinge fulcrum, and the distance between the two equal-length levers is based on the two symmetrical notch grooves that are conveniently placed in the outer ring spacer (4); before measuring, place the washer (1 ) on the measuring platform, place the inner ring (2) of bearing I on the washer (1), then place the outer ring spacer (4) on the outer ring (3) of bearing I, and place the outer ring (4) of bearing II Place the outer ring (5) on the outer ring spacer (4), pay attention to the fact that the large end face of the outer ring of bearing I and the large end face of the outer ring of bearing II pass through the outer ring spacer (4) back to back, and finally place the inner diameter load block of the counterweight (7) Put it in the inner ring (6) of the bearing II; adjust the measuring system so that the two equal-length levers are parallel to each other, and the pointer of the measuring instrument at this time is calibrated to zero, and pass through the two notched grooves of the outer ring spacer (4) Insert one end of the two equal-length levers with right-angle probes into the outer ring spacer; when measuring, the inner diameter load block (7) of the counterweight applies axial load to bearing I and bearing II, and the two right-angle probes First align the center point A of the radial width of the inner ring of bearing I and bearing II. At this time, the center point A will display a value A through the measuring instrument, and then move the two right-angle probes and align them with the center point A of bearing I and bearing II. The center point B of the radial width of the outer ring, the center point B will display a B value through the measuring instrument, calculate the difference between the A value and the B value, if the A value minus the B value is equal to δ and δ is a negative value, it indicates that the bearing I and bearing II are paired with pre-clearance, that is, the axial clearance of bearing I and bearing II is δ; if the value of A minus the value of B is equal to δ and δ is a positive value, it means that bearing I and bearing II are paired with preload , that is, the preload clearance of bearing I and bearing II is δ, and the axial direction of bearing I and bearing II should be preloaded when they are paired; measure Mark the measurement results and the counterweight of the inner diameter load block (7) on the end faces of bearing I and bearing II.

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