JPS58171258A - Method and apparatus for grinding ball bearing - Google Patents

Abstract

PURPOSE:To increase the production efficiency of a ball bearing and to make possible the quality uniform, by making the operation automated and continuous, in adjusting and grinding means for adjusting and grinding the end surfaces of an inner or outer ring of a ball bearing. CONSTITUTION:In the flow chart of the method of grinding, GA and GB are values that will be obtained by measuring the end surfaces of the inner ring and outer ring of the ball bearing to be machined by a measuring apparatus. At every definite short interval, sampling values of GA and GB are digitized to obtain the average values at every rotation. These average values GA and GB are calculated at every rotation of a work head, and the difference GAV=the average GB-the average GA is also calculated at every rotation. Based upon the calculated difference GAV, the feeding rate of the grind stone is determined to grind the end surfaces of the inner ring of the ball bearing. Thus, the operation for improving the accuracy of the differential width is made automated and continuous, so that the production efficiency can be improved and the quality can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION (3) The present invention relates to a method and apparatus for grinding a ball bearing, and more particularly to a method and apparatus for adjusting and grinding an end face of an inner ring or an outer ring of a ball bearing.

Ball bearings are the most typical type of rolling bearings, and two or more are generally used in combination. In this combination, in order to accurately position the shaft in the radial and axial directions and to suppress vibration of the shaft, the rigidity of the bearing must be increased to prevent abnormal noise due to axial vibration and resonance.
When a bearing is assembled for purposes such as keeping the rolling elements in the correct position with respect to the bearing ring, internal stress may be generated in the bearing in advance. This type of usage is called the preload method. There is a fixed position preloading method as a preloading method for a combination bearing, and this method is a method in which the relative positions of opposing bearings in the axial direction do not change even when the bearings are in use. In order to assemble and fasten bearings using this fixed-position preload method, the bearings must be manufactured so that the end face positions of the inner and outer rings of the bearing match when the preload is applied to the bearing (4). However, ball bearings generally have an outer ring,
The inner ring and rolling elements are manufactured separately, and then the outer ring, inner ring, and rolling elements are combined. Because the manufactured outer ring, inner ring, and rolling elements differ in manufacturing accuracy, the assembled bearing also has variations in the assembly degree.
It is particularly large in the distance between the end face position of the inner ring and the end face position of the outer ring (hereinafter referred to as the difference width). However, in ball bearings that require high precision, variations in bearing differential width precision are a fatal flaw. Therefore, conventionally, in order to improve the width difference accuracy, the end face of the inner ring or outer ring has been adjusted and ground by the following method. After combining the inner ring, outer ring, and rolling elements that were manufactured separately into a ball bearing, the inner ring and outer ring are manually rotated relative to each other while applying a certain preload (approximately 5 to 10 Ai7) between the inner ring and outer ring to form the rolling elements. The position of the wheel relative to the inner and outer rings is stabilized (hereinafter referred to as blending rotation).

After performing this familiarization rotation, measure the position of each end face of the inner ring and outer ring while applying the above-mentioned constant preload between the inner ring and outer ring, and apply the preload to the measured value. Calculate the amount to be ground so that the width is zero,
A skilled worker manually grinds the specified surface by this calculated value using a rotary grinder. Then, after manual grinding, measure the end faces (i'f) of the inner and outer rings of the bearing and check whether the difference width is within the specified range. Then, the grinding process was repeated again using the method described above.

However, with this method, the work process involves manual blending and rotation,
Production efficiency is poor because manual measurement of the end face position of the inner ring and outer ring, calculation of the amount to be ground, calculation of the amount to be ground, and grinding requires skilled workers. This has the disadvantage that work efficiency is low and grinding requires skill, and since the work relies on manual labor, high precision cannot be expected.Furthermore, the bearing is magnetically chucked to a rotary table during grinding, so the bearing is It requires magnetization and demagnetization, but it has the disadvantage that complete demagnetization is difficult in the assembled state.

In order to eliminate the above-mentioned drawbacks, we have developed an automatic grinding device that can perform all of the above-mentioned steps continuously using an automated machine and a flln machine. By using this automatic grinding device, it is possible to easily produce thick ball bearings with high accuracy in differential width.

The purpose of the present invention is to automate and serialize the work of 1": 1lll receiver difference + 111 accuracy, H nozzle, which was conventionally done manually by dividing it into various parts, improve production efficiency, improve difference width accuracy, An object of the present invention is to provide a ball bearing grinding device that enables uniform quality.

In the present invention, the same 1
It is characterized by automating the rotation.

Furthermore, the present invention is characterized in that it includes a device that can grind the ball bearing while applying a constant preload between the inner ring and the outer ring.

(7) Furthermore, in the present invention, when determining the end face positions of the inner ring and outer ring of a ball bearing, the measured values of the end face positions are digitally sampled, and the end face positions of the inner ring and outer ring are measured using the work head 1.
It is characterized by being averaged for each rotation.

Furthermore, the present invention is characterized in that when grinding the end faces of the inner ring or outer ring of the bearing, the positions of the end faces of the inner ring and outer ring are simultaneously measured, and the grinding is performed in an open loop to a target value.

Furthermore, the present invention has many other features which will become apparent from the following description of the illustrated embodiment.

FIG. 1 shows a ball bearing ground by the ball bearing grinding device of the present invention, and δ shown in the figure is the difference width. FIG. 2 shows a state in which two ball bearings shown in FIG. 1 are assembled back to back, and the difference in width between the bearings is δmari. If the inner ring of the combination bearing is fed in the axial direction with a FaoO force in this state, the bearing openings will change by δa6, and the gap 2δa (1 will disappear) between the inner rings (8).In this state, the bearing This means that a preload of Fa(1) is applied.

Further, even if Fao is increased further, the amount of preload applied to the bearing will not increase. Furthermore, if the amount of preload is increased more than necessary, it will cause abnormal heat generation, an increase in frictional moment, and a decrease in fatigue life, so it is necessary to set the amount of preload appropriately. As mentioned above, the amount of preload depends on the width difference dimension, so it is necessary to improve the accuracy of the difference width gluing method.

FIG. 3 shows a work head in which a ball bearing to be machined is mounted in the apparatus of the present invention. Reference numeral 1 denotes a main shaft in which four fluid supply holes are separately formed. A fluid supply rotary joint (not shown) is attached to the main shaft 1 so that fluid can be supplied to each fluid supply hole. Furthermore, an external fluid supply source is connected to the other end of the rotary joint via a solenoid valve (not shown). By switching the solenoid valve ξ, it is possible to release the fluid pressure to each fluid supply hole and switch the pressure.

A chuck mounting plate 2 is attached to the front surface of this main shaft (on the right side in FIG. 3). Further, on the front surface of the chuck mounting plate 2, as shown in the figure, a clamp ring holding ring 3 for holding the clamp ring 5 and a load piston 4 for applying preload between the inner ring and outer ring of the ball bearing to be machined are attached. be. The method of applying preload is based on Utility Model Application No. 56-1263.
It is explained in detail in No. 47.

The load cylinder 6 is engaged with the outside of the load piston by means of an air bearing capable of relative movement such that it can rotate freely under low load and can freely slide in the axial direction. The clamp ring 5 is slidable in the axial direction and engaged with the load cylinder by a key means 10 that rotates as one unit in the rotational direction, and is connected to the clamp ring retaining ring 3 so that the clamp ring 5 can freely rotate under low load and is connected to the shaft. An air bearing 13 that is slidable in this direction is engaged with the inside of the clamp ring holding ring 3. Furthermore, load cylinder 6
As shown in the figure, the chuck mounting plate 2 forms an ejecting cylinder chamber A used for mounting and removing the ball bearing to be machined, and a fluid for supplying fluid pressure to the cylinder chamber A. A supply hole a is formed in the mounting plate 2. This fluid supply hole a is communicated with one of the four fluid supply holes formed in the main shaft 1, and external fluid pressure is supplied via a fluid supply rotary joint (not shown) and a solenoid valve (not shown). It is connected to a power supply (not shown) and enables supply of fluid pressure to the cylinder chamber A and release of the pressure.

Further, as shown in the figure, the load cylinder 6 and the load piston 4 form a preload applying cylinder chamber B for applying preload to the inner ring and outer ring of the ball bearing to be machined, and a cylinder chamber B for supplying fluid pressure to the cylinder chamber B. The fluid supply hole of the load piston 4
It is formed inside. This fluid supply hole is communicated with another fluid supply hole other than the one with which the fluid supply hole a formed in the main shaft 1 is connected, and is connected to a fluid supply rotary joint (not shown), a solenoid valve, and a pressure It is connected to an external fluid supply source (not shown) via a regulating valve (not shown), allowing high pressure supply, low pressure supply, and pressure release of fluid pressure to the cylinder chamber B.

The clamp ring 5 and the clamp ring holding ring 3 form a clamp cylinder chamber C for switching between rotating the inner and outer rings of the bearing together or separately. A fluid supply hole C for supplying pressure is formed in the clamp ring holding ring 3 and the chuck mounting plate 2.

The fluid supply hole C is communicated with a fluid supply hole formed in the main shaft 1, which is different from the one with which the fluid supply holes a and b communicate, and is connected to a fluid supply rotary joint (not shown) and a solenoid valve (
It is connected to an external fluid supply source (not shown) via an external fluid supply source (not shown), making it possible to supply fluid pressure to the cylinder chamber C and release the pressure. Further, air bearings 11, 12 are formed in the load piston 4 to supply the load piston 4 and the load cylinder 6 with each other in a freely rotatable and axially slidable manner with a low load. Bearing 11. ．． A fluid pressure supply hole d for supplying fluid pressure to the load piston 4 and the chuck mounting plate 2 is formed in the load piston 4 and the chuck mounting plate 2. Further, an air bearing 13 is formed in the clamp ring retaining ring 3 to engage the clamp ring retaining ring 3 and the clamp ring 5 so that the clamp ring retaining ring 3 and the clamp ring 5 can rotate freely and slidably in the axial direction with a low load. A fluid supply hole e for supplying fluid pressure to the core bearings 13, 14 is formed in the chuck mounting plate 2. The fluid supply holes d and θ are communicated with a fluid supply hole formed in a main shaft other than the one with which the fluid supply holes a1b and C are communicated, and are connected to a fluid supply rotary joint (not shown) and a pressure adjustment hole. It is connected to an external fluid supply source through a valve (not shown) to close the supply pressure release of fluid pressure to the air bearings 11, 12 and 13. Forming each fluid supply hole in a rotating body in this manner is a technique well known to those skilled in the art.

A backing plate 7 is replaceably attached to the front end of the load piston as shown in the figure, and the inner ring hole of the ball bearing W to be machined is fitted into the boss portion 15 of the backing plate 7.
The front end surface of the inner ring of the machined ball bearing W in the second cover 711 is in close contact with the upper seating surface 18. Further, an outer cylinder 8 is detachably attached to the front end of the load cylinder 6 by means of a locking mechanism as disclosed in, for example, Japanese Utility Model Application No. 56-123467. An annular pressing plate 9 is fixed to the outer cylinder 8 so as to be able to press the rear end surface of the outer ring of the ball bearing W to be machined.

It is preferable that the presser plate 9 is made of an elastic material and can elastically press the rear end surface of the outer ring of the machined ball bearing W. Further, the backing plate 7 may be formed integrally with the load piston 4.

In the apparatus of the present invention having the above configuration, the ball bearing W to be processed is
When installing the ejection cylinder chamber A, a regulated fluid pressure is supplied to the ejection cylinder chamber A through the fluid supply hole a. This pushes the load cylinder 6 forward (to the right in FIG. 3).

Next, the ball bearing W to be machined is loaded with its front end face facing the backing plate 7 as shown in the figure, and then pressure-adjusted fluid is supplied to the clamping cylinder chamber C through the fluid supply hole C, and the end face of the clamp ring 5 is 19 is pressed against the chuck plate 2 to prevent the clamp ring 5 from rotating, and to prevent the load cylinder, which is integrated with the clamp ring 5 through the key 10, from rotating. And the ball bearing W to be machined
The outer ring end face pressing ring 9 and the outer cylinder 8 are hooked to the load cylinder 6. This latching method is described in detail in Utility Model Application No. 56-126347.

By the above-mentioned operations, the nuclear force 1-pin 1-hole I-engine bearing W is installed in the present grinding machine.

Next, press the cycle start button (not shown) on the device. When this cycle button is pressed, the following operations are automatically performed in the order described below: smooth rotation, measurement of the difference width, application of preload between the inner and outer rings, and grinding of the inner or outer ring.

Pressing down the cycle start button stops the pressure supply to the clamp cylinder chamber C mentioned above and closes the fluid hole C.
leaks through the clamp ring 5 and chuck mounting plate 2.
Release the bond between the Adjusted fluid pressure is constantly supplied to the air bearing in the load cylinder 6 and the clamp ring outer peripheral support plate 3, and the load cylinder 4 and the load piston 6 are made rotatable and axially slidable under low load, and are clamped. The ring 5 and the clamp ring outer peripheral support plate 3 are also rotatable and slidable in the axial direction with a low load. Next, the pressure in the ejection cylinder chamber A is leaked through the fluid supply hole a, and the pressure is regulated to a low pressure in the preloading cylinder chamber B (the load on the ball bearing to be machined is 5 to 20 kg).
Supply fluid pressure 71) to push the load cylinder 6 to the left, push the outer ring of the bearing to the left via the outer cylinder 8 and the outer ring end pressing ring 9, and the inner ring is supported by the backing plate 7. (15) A load is applied between the inner and outer rings of the ball bearing being machined.

Therefore, the main shaft is rotated at a low speed (about 200 rpm).

At this time, the inner ring of the ball bearing to be processed, the backing plate 7
, the load piston 4, the chuck mounting plate 2, and the main shaft 1 (hereinafter referred to as the inner ring) are integrally rotated on a concentric axis, and the outer ring of the ball bearing to be processed, the outer ring pressing plate 9, the outer cylinder 8, the load cylinder 6, and the clamp ring 5 The outer ring (hereinafter referred to as the outer ring) is engaged with the inner ring so that it can rotate freely under low load through an air bearing, so it rotates behind the inner ring due to inertia, rotates relative to the outer ring and the inner ring, and as a result, the inner ring and outer ring are integrated with each other. Relative rotation occurs between the inner ring and outer ring of the rotating workpiece ball bearing.

This performs a blending rotation.

After rotating the main shaft 1 at a low speed for a certain period of time, the adjusted fluid pressure is supplied to the clamping cylinder chamber C through the fluid supply hole C to press the end surface 19 of the clamp ring 5 against the chuck mounting plate. Due to frictional force, the inner ring and outer ring (
16) Rotates as one.

Next, a regulated high fluid pressure (pressure that applies a load of the required magnitude between the inner and outer rings of the ball bearing to be machined) is supplied to the cylinder chamber B through the fluid supply hole b Apply preload between the wheels.

Next, the measuring instrument 16 is automatically brought into contact with the end faces of the inner ring and outer ring of the ball bearing to be machined as shown in the figure, and the position of the end faces begins to be measured. When performing grinding, the apparatus of the present invention uses the method described below.

FIG. 4 shows a flowchart of the grinding method. In FIG. 4, GA and GB are values measured by the measuring device 16 of the inner ring and outer ring end faces of the ball bearing W to be machined. G.J., G.
Since B is an analog value, it is converted to a digital value using an AD converter to facilitate calculation processing.

As described above, after the measuring device 16 contacts the end surfaces of the inner ring and outer ring of the ball bearing W to be machined, GAXGll is measured while the inner ring and outer ring are making one revolution, and QA and G8 are sampled at regular minute intervals. The sampled values are digitized and the average value is taken every rotation. Here, one rotation is detected by a proximity switch. This is illustrated in FIG. GA and GB are measured every minute time and are GAIXG.
A2, -GAn XG11l I GB2, -QB
When n is the average value GA and G 17 FiGAI
+GA2- G'n/n XGB1+GII2 ・-
GBn/n. These average values GA and Q/j are calculated for each rotation of the work head, and the difference between the average values Qip =
Qt+-Qi is also calculated for each rotation. Based on this calculated JL and GAV, the feed li of the grinding wheel is determined and the inner ring end face of the bearing is ground.

By averaging the end face positions in this device in this way, the non-ground surface that is not supported by the backing plate (the outer ring end face in the embodiment shown in Fig. 3) has a large runout, which causes a large measurement error and the difference in width accuracy ( We were able to eliminate the drawback of not improving the performance.Also, there are two types of grinding with this device: rough grinding and finish grinding.(19) As shown in the latter half of the flow chart in Figure 4, the average value
When V is above a certain value γ, grinding is performed at the rough grinding feed rate, and when the positive becomes smaller than γ, the feed rate is changed to the finish grinding rate and finish grinding is performed, and furthermore, the door is lower than the constant value δ. When the size becomes smaller, stop the grinding wheel feed and continue grinding with spark-out grinding until GAV≦ε(ε
When the desired difference width value is reached, the grinding wheel 17 is removed from the ball bearing to be machined, and the measuring device 16 is also automatically removed from the end faces of the inner and outer rings, and a grinding completion lamp (not shown) is displayed.
lights up and stops the device.

Here, the planar position of the inner ring end face can be calculated by using an instantaneous value without calculating an average value because the inner ring end face is pressed and fixed in one direction by the backing plate, so there is little wobbling. With the above steps, the automatic grinding of the difference width of the ball bearing W to be machined is completed. Next, the ball bearing W to be processed is removed from the device.

Furthermore, the embodiment shown in FIG. 6 is a grinding device for grinding the outer ring end face of a 1-bit ball bearing in order to set the frontal difference width to -(20). This is shown in FIG.

Furthermore, it is also possible to use the device of the present invention not as a grinding device but as a measuring device for measuring only the inner ring or outer ring of a ball bearing.

As described above, the device of the present invention automatically and continuously performs measurement of rotation and grinding to reduce the number of work steps, and grinds while measuring, making it possible to mass produce bearings with high precision in differential width. do. Furthermore, since the work is automated, even unskilled workers can perform highly accurate processing. Furthermore, the back width can be adjusted and ground while applying a predetermined preload to the ball bearing to be machined, making it possible to perform machining more suited to the actual usage conditions.The preload can be easily changed by adjusting the pressure, and during machining. The inner and outer rings of the ball bearing to be machined rotate as one unit, and there is no phase t1 movement, so the bearing raceway surface and rolling elements (balls) are not damaged by falling particles from the grindstone, etc., so the bearing accuracy changes before and after machining. Reduces the cost of precision angular contact ball bearings without the need for troublesome process control as described above.
It has a great effect on improving productivity and accuracy. Furthermore, when using a bearing, there is a method of inserting a spacer between the inner and outer rings to adjust the width difference, but in that case, the spacers need only be manufactured to the same dimensions, so such an adjustment spacer is not necessary.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the difference width in ball bearings; Fig. 2 is an explanatory diagram of the back-to-back combination of ball bearings; Fig. 3 is an explanatory diagram of the work head of a grinding machine according to the present invention; Fig. 4 is an explanatory diagram of the work head according to the present invention A flowchart showing the amount of grinding and the grinding method. FIG. 5 is an explanatory diagram of calculating the average value of the inner ring and outer ring of a ball bearing to be machined according to the present invention. FIG. 6 is an explanatory diagram of another embodiment according to the present invention. Explanation of part symbols] Inner ring rotating member...1.2.3.4.7.15 Outer ring rotating member...5.6.8.9 Means for rotatably engaging ...11.12.13 Switching means・
...C, c Applicant NSK Ltd. (23) Figure 1 Figure 2

Claims (1)

[Claims] 1° A constant axial load is applied between the inner and outer rings of a ball bearing assembly, the plane positions of the inner and outer rings are detected, and the amount to be ground is calculated based on the detected values. In a ball bearing grinding method in which one of the flat surfaces of the inner and outer rings is ground by the amount to be ground so that the difference in plane position between the inner ring and the outer ring becomes a predetermined value, every rotation of a partially ground ball bearing is performed. A method for grinding a ball bearing, characterized in that the average value of each plane position of the inner and outer rings is calculated, and the amount to be ground is calculated and ground based on the average value. 2. In the ball bearing grinding method according to claim 1, when calculating the amount to be ground based on the average value, the average value of the plane position of the non-grinded surface and the instantaneous plane position of the surface to be ground A ball bearing grinding force F, which is characterized by calculating the amount of grinding based on the difference between the detected value and the detected value. e. 3. In the ball bearing grinding method according to claim 1, when calculating the amount to be ground based on the average value, the amount to be ground is calculated based on the difference between the respective average values of the planar positions of the inner ring and the outer ring. A ball bearing grinding method characterized by calculating the amount of grinding to be performed. 4. In a ball bearing grinding device that includes means for applying a constant axial load between the inner and outer rings of a ball bearing assembly during grinding, an inner ring rotating member that rotates as one unit with the inner ring of the ball bearing and an outer ring of the ball bearing. an outer ring rotating member that rotates concentrically with the inner ring rotating portion opening; means for rotatably engaging the inner ring rotating member and the outer ring rotating member with a low load; the inner ring rotating member and the outer ring rotating member; means for switching whether to rotate the inner ring rotating member and the outer ring rotating member separately; A constant axial load is applied between the rings, and only one of the inner ring rotating member and the outer ring rotating member rotates, thereby causing the inner ring rotating member and the outer ring rotating member to rotate relative to each other, thereby reducing the inner ring of the ball bearing. and the outer rings are rotated relative to each other so that they become familiar, and then the inner ring rotating member and the outer ring rotating member are rotated as one body by switching the switching means to grind either the inner ring or the outer ring of the bearing. Features of ball bearing grinding equipment. 5. The ball bearing grinding device according to claim 4, characterized in that the engaging means is an air bearing.
1 ball bearing grinding device.