JPS6247668B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ball bearing grinding device, and more particularly to a device for adjusting and grinding the end face of an inner ring or an outer ring of a ball bearing.

BACKGROUND OF THE INVENTION AND PRIOR ART Ball bearings are the most typical type of rolling bearings, and two or more are generally used in combination.
This combination is used to accurately position the shaft in the radial and axial directions, to suppress shaft runout, to increase the rigidity of the bearing, to prevent abnormal noise due to axial vibration and resonance, and to prevent vibrations from the bearing ring. When a bearing is assembled for purposes such as keeping the rolling elements in the correct position, 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 faces of the inner ring and outer ring are aligned when the preload is applied to the bearing in actual use. However, ball bearings are generally manufactured by combining an outer ring, an inner ring, and rolling elements that are manufactured separately and then assembled together. Because the manufactured outer ring, inner ring, and rolling elements each have different manufacturing precision, the assembled bearing also has variations in assembly precision.This is particularly due to 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). Large in size. 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 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 kg) 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, the position of each end face of the inner ring and outer ring was measured while applying the above-mentioned constant preload between the inner ring and outer ring, and based on the measured values, the preload for actual use was applied. The amount of grinding that should be done so that the difference width is zero is calculated, and a skilled worker uses a rotary grinder to manually grind the designated surface by this calculated value. After manual grinding, the end face positions of the inner and outer rings of the bearing are measured again to check whether the difference width is within the predetermined range. If the measured difference width is not within the predetermined range, repeat the method described above. Grinding was repeated.

However, this method has poor production efficiency as it involves many work processes such as manual rotation for smoothing, manual measurement of the end face positions of the inner and outer rings, calculation of the amount to be ground, and grinding by skilled workers. Since calculation of the desired amount and grinding are dependent on manual labor, work efficiency is low and grinding work requires skill. Since the bearing is magnetically chucked to the rotary table, the bearing becomes magnetized and must be demagnetized, but it has the disadvantage that complete demagnetization is difficult in the assembled state.

OBJECTS OF THE INVENTION An object of the present invention is to provide an automatic grinding device that can automate all of the above-mentioned steps and continuously perform them using a computer in order to eliminate the above-mentioned drawbacks. By using this automatic grinding device, it becomes possible to easily mass-produce ball bearings with high precision in differential width. The purpose of the present invention is to automate and serialize the work to improve the precision of the difference width of ball bearings, which was previously done in various parts by workers, thereby improving production efficiency, improving the precision of the difference width, and making quality uniform. The purpose of the present invention is to provide a ball bearing grinding device that enables the following.

The present invention is characterized by automating the blending rotation, which has been considered difficult to automate in the past.

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.

Furthermore, the present invention is characterized in that when determining the end face positions of the inner ring and outer ring of the 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 determined by averaging each rotation of the work head. .

Furthermore, in the present invention, when grinding the end face of the inner ring or outer ring of the bearing, the end face positions of the inner ring and outer ring are simultaneously measured, and the grinding is performed in an open loop only while the average value for each rotation of the workpiece is calculated with respect to the target value. It is characterized by

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

Description of Examples Explanation of Difference Width 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 width of each bearing is δ _ap . In this condition, the inner ring of the combination bearing is axially F.
When tightened with a force of _ap , bearings A and B each change by δ _ap , and the clearance 2δ _ap between the inner rings disappears. In this state, a preload of F _ap is applied to the bearing. Furthermore, even if F _ap 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. Since the amount of preload depends on the width difference as described above, it is necessary to improve the dimensional accuracy of the width difference.

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 this solenoid valve, it is possible to release the fluid pressure to each fluid supply hole and to switch the pressure.

A chuck mounting plate 2 is attached to the front surface (on the right side in FIG. 3) of this main shaft. Furthermore, as shown in the figure, a clamp ring holding ring 3 for holding a 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 to the front surface of the chuck mounting plate 2. be.
The method of applying preload is explained in detail in Utility Model Application No. 126347/1983.

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 freely rotate and slide freely in the axial direction under a low load. The clamp ring 5 is slidable in the axial direction and is engaged with the load cylinder by a key means 10 that rotates as one unit in the rotation direction, and is connected to the clamp ring retaining ring 3 to be freely rotatable under low load and in the axial direction. The clamp ring retaining ring 3 is engaged with the inside of the clamp ring retaining ring 3 by an air bearing 13 which is slidable therein. Furthermore, the load cylinder 6 and the chuck mounting plate 2 form an ejection cylinder chamber A, which is used when installing and removing a ball bearing to be machined from the device, as shown in the figure, and a cylinder chamber A for supplying fluid pressure to this cylinder chamber A. A fluid supply hole a is formed in the chuck 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.

In addition, 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 to supply fluid pressure to this cylinder chamber B. A fluid supply hole b is formed in the load piston 4. This fluid supply hole b is different from the one with which the fluid supply hole a formed in the main shaft 1 communicates.
It is connected to an external fluid supply source (not shown) through a fluid supply rotary joint (not shown), a solenoid valve, and a pressure regulating valve (not shown), and is connected to an external fluid supply source (not shown) to supply fluid to cylinder chamber B. It enables high pressure supply, low pressure supply and pressure release.

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. The fluid supply hole c for supplying pressure is connected to the clamp ring holding ring 3 and the chuck mounting plate 2.
It is formed inside. The fluid supply hole c is connected to 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 are connected, and is connected to a fluid supply rotary joint (not shown) and a solenoid valve (not shown). 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 and 12 are formed in the load piston 4 for supplying the load piston 4 and the load cylinder 6 mutually with a low load so as to be rotatable and slidable in the axial direction. 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. In addition, an air bearing 13 is attached to the clamp ring retaining ring 3 for rotatably and slidably engaging the clamp ring retaining ring 3 and the clamp ring 5 under low load.
It is formed inside. This air bearing 13,1
A fluid supply hole e is formed in the chuck mounting plate 2 for supplying fluid pressure to the chuck mounting plate 2. The fluid supply holes d and e communicate with a fluid supply hole formed in a main shaft other than the one with which the fluid supply holes a, b, and e communicate, and are connected to a fluid supply rotary joint (not shown).
and air bearings 11, 12 and 13 connected to an external fluid supply via pressure regulating valves (not shown).
It is possible to release the supply pressure of fluid pressure to. Forming each fluid supply hole in a rotating body in this manner is well known to those skilled in the art.

A bucking 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 bucking plate 7, and the seat surface 18 on the bucking plate 7 is fitted into the boss portion 15. The front end face of the inner ring of the ball bearing W to be machined is in close contact with each other. Further, an outer cylinder 8 is detachably attached to the front end of the load cylinder 6 by a locking mechanism such as that disclosed in the above-mentioned utility model publication. An annular pressing plate 9 is fixed to the outer cylinder 8 and can 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 bucking plate 7 may be formed integrally with the load piston 4.

In the apparatus of the present invention having the above structure, when the ball bearing W to be machined is mounted, 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 bucking plate 7 as shown in the figure, and then loaded into the clamping cylinder chamber C.
A pressure-adjusted fluid is supplied to the end face 19 of the clamp ring 5 through the fluid supply hole c to the chuck mounting plate 2.
This prevents the clamp ring 5 from rotating, and prevents the load cylinder, which is integrated with the clamp ring 5 through the key 10, from rotating. Then, the outer ring end face pressing ring 9 and the outer cylinder 8 of the ball bearing W to be machined are hooked to the load cylinder 6. This latching method is described in detail in Utility Model Application Publication No. 56-126347.

The ball bearing W to be machined obtained through the above operations is mounted on the present grinding apparatus.

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

When the cycle start button is pressed down, the pressure supply to the clamp cylinder chamber C is stopped and leaks through the fluid hole c, releasing the fixation between the clamp ring 5 and the chuck mounting plate 2.
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 periphery 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 adjusted to a low pressure in the preloading cylinder chamber B (fluid pressure at which the load on the ball bearing to be machined is approximately 5 to 50 kg). ) and pushes the load cylinder 6 to the left, pushing the outer ring of the bearing to the left via the outer cylinder 8 and the outer ring end face pressing ring 9. Since the inner ring is supported by the bucking plate 7, the ball bearing to be machined is Load is applied between the inner and outer rings.

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
The main shaft 1 (hereinafter referred to as the inner ring) is integrally rotated around a concentric shaft, and the outer ring of the ball bearing to be processed, the outer ring pressing plate 9,
Outer cylinder 8, load cylinder 6, and clamp ring 5
The outer ring (hereinafter referred to as the outer ring) is engaged with the inner ring through an air bearing so that it can rotate freely under low load, so due to inertia it falls behind the inner ring and rotates, causing relative rotation between the outer ring and the inner ring, and as a result, the inner ring and outer ring become integral 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, adjusted fluid pressure is supplied to the clamp 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, and the friction force of this pressing surface is applied. This causes the inner ring and outer ring to rotate as one.

Next, a high adjusted 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 holes b and b'. Apply preload between the inner and outer rings.

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.

Grinding procedure using the above device FIG. 4 shows a flowchart of the grinding method. In Fig. 4, G _A and G _B are the workpiece ball bearings W
These are the values measured by the measuring device 16 of the inner ring and outer ring end faces of. Since G _A and G _B are analog values, they are converted to digital values using an A-D converter to facilitate calculation processing.

As mentioned above, the measuring device 16 is the ball bearing W to be machined.
After contacting the end faces of the inner and outer rings, G _A and G _B are measured while the inner ring and outer ring make one rotation, and G _A and G _B are sampled at regular minute intervals and the sampled values are digitized. Take the average value for each rotation. Here, one rotation is detected by a proximity switch. This is illustrated in FIG. G _A and G _B measured at minute intervals are G _A1 , G _A2 , ......
G _Ao , G _B1 , G _B2 , ...... G _Bo , the average values _A and _B to be obtained are G _A1 + G _A2 ...... G _Ao/o , G _B1
+G _B2 ......G _Bo/o . This average value _A and
_B is calculated every revolution of the work head, and the difference between the average values S _AV = _B - _A is also calculated every revolution.
Based on this calculated G _AV , the feed amount of the grinding wheel is determined and the inner ring end face of the bearing is ground.

For example, when the inner ring is fixed and the outer ring is rotated by applying a load to the outer ring, even if the outer ring rotates tilted due to the eccentric load, by taking the average, the virtual plane height of the outer ring plane at the center of the inner ring can be obtained, and the true difference width is computable.

By averaging the end face positions in this device in this way, the non-ground surface that is not supported by the bucking plate (the outer ring end face in the embodiment shown in Fig. 3) has a large runout, which causes a large measurement error and reduces the difference width accuracy. We were able to overcome the drawback of not improving. In addition, there are two types of grinding with this device: rough grinding and finish grinding.As shown in the latter part of the flowchart in Figure 4, when the average value G _AV is greater than a certain value r, grinding is performed at the rough grinding feed rate. When G _AV becomes smaller than r, change the feed speed to finish grinding feed and perform finish grinding, and when _AV becomes smaller than a certain value δ, stop the grinding wheel feed and perform spark-out grinding. Continue grinding and G _AV ≦
When ε (ε is 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 automatically removed from the end faces of the inner and outer rings, a grinding completion lamp (not shown) is turned on, and the apparatus is stopped.

The above operations are automatically controlled using a computer.

Here, the planar position of the inner ring end face can be calculated by using an instantaneous value without calculating an average value since the inner ring end face is pressed and fixed in one direction by the bucking 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.

DESCRIPTION OF ANOTHER EMBODIMENT Furthermore, the embodiment shown in FIG. 6 is a grinding device for grinding the outer ring end face of a ball bearing to be machined in order to make the frontal difference width constant.

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.

Effects of the Invention As stated above, the device of the present invention automatically and continuously performs measurement of rotation and grinding to reduce the number of work steps and performs grinding while measuring, making it possible to mass produce bearings with high precision in differential width. is possible. 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 relative movement, so the bearing raceway surface and rolling elements (balls) are not damaged by falling particles from the grinding wheel, etc., so bearing accuracy is maintained before and after machining. It does not change and does not require the troublesome process control as described above, and has great effects on cost reduction, productivity improvement, and accuracy improvement of precision angular ball bearings. 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 the drawing]

Fig. 1 is an explanatory diagram of the difference width in the ball bearing; Fig. 2 is an explanatory diagram of the back-to-back combination of the ball bearings; Fig. 3 is an explanatory diagram of the work head of the grinding machine according to the present invention;
The figure is a flowchart showing the amount of grinding and the grinding method according to the present invention, Figure 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, and Figure 6 is another embodiment according to the present invention. Explanatory diagram, [Explanation of symbols of main parts], Inner ring rotating member...
1, 2, 3, 4, 7, 15, outer ring rotating member...
5, 6, 8, 9, means for rotatably engaging...1
1, 12, 13, switching means...C, c.

Claims (1)

[Claims] 1. In a ball bearing grinding device: an inner ring rotating means for holding an inner ring of a ball bearing to be ground and rotating the inner ring around a predetermined axis; an outer ring rotating means for rotating the inner ring around the predetermined axis; an engaging/disengaging means for engaging/disengaging the inner ring rotating means and the outer ring rotating means; controlling the engaging/disengaging means to connect the outer ring and the outer ring. a selection means for selecting whether to rotate the inner ring integrally or independently; acting on the inner ring rotation means and the outer ring rotation means to rotate the inner ring held by the inner ring rotation means and the outer ring; load applying means for applying a constant axial load between the inner ring and the outer ring held by the means; controlling the selection means, the load applying means and the grinding means to initially apply a constant axial load between the inner ring and the outer ring; The inner ring rotating means and the outer ring rotating means are rotated relative to each other under a low load in the axial direction, and then the inner ring rotating means and the outer ring rotating means are rotated integrally, and the inner ring or a control means for causing the grinding means to grind either one of the outer rings while applying a constant axial load. 2. The ball bearing grinding device according to claim 1, wherein the engagement/disengagement means is an air bearing. 3. The ball bearing grinding device according to claim 1, wherein the control means is adjacent to a surface of the inner ring or the outer ring in the radial direction and includes a measuring means for measuring a plane displacement of the surface, A ball bearing grinding device characterized in that the average value of each plane position of the inner and outer rings is calculated every rotation, the amount to be ground is calculated based on the average value, and the grinding device is controlled to perform the grinding. 4. In the ball bearing grinding device according to claim 3, when calculating the amount to be ground based on the average value, detecting the average value of the plane position of the non-grinding surface and the instantaneous plane position of the surface to be ground. A ball bearing grinding device characterized by calculating the amount of grinding based on the difference between the two values. 5. In the ball bearing grinding device according to claim 3, when calculating the amount to be ground based on the average value, grinding is performed 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 device characterized by calculating the amount.