JP3928252B2 - Sphere polishing method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a sphere polishing method for polishing a sphere, for example, a steel ball (ball) used for a ball bearing or the like.
In particular, changes in processing conditions between lots due to the fact that the quantity per sphere to be processed (hereinafter referred to as “lot quantity”) is not constant, and the resulting variation in the dimensional accuracy of the spheres between lots are prevented. On how to do.
[0002]
[Prior art]
Conventionally, as a polishing apparatus used for polishing this type of sphere, for example, an apparatus shown in FIG. 1 is known.
[0003]
In FIG. 1, an annular groove approximating the radius of curvature of a sphere (ball) 3 to be polished is provided in each of a rotating rotating disk body 1 and a stationary stationary disk body 2 positioned coaxially and opposed thereto. A plurality of (ball grooves) 4 are provided concentrically. An annular groove (not shown) 4 of the rotating disk body 1 and an annular groove 4 of the stationary disk body 2 face each other, and each pair of the annular grooves 4 constituting one of the polishing circuits constitutes one of the polishing circuits to polish the ball 3. It is configured to process. The applicant of the present invention has previously filed an application in which a bearing that supports the rotating disk body 1 (actually, a rotating shaft integrated therewith) is an oil hydrostatic rotary bearing and the slide guide mechanism is an oil hydrostatic guide. (Japanese Patent Application No. 9-87220). This is because the rotational accuracy is improved by making the rotary bearing a static pressure, and the processing of the ball is performed by making the slide guide mechanism a static pressure guide, thereby improving the control of the pressing force by the pressing mechanism. The accuracy is improved.
[0004]
In the polishing process, the spherical body 3 is continuously supplied from the rotating conveyor 5 rotating in a dish shape to the polishing circuit via the entrance chute 6, and the rotating disk body 1 is rotated while the rotating disk body 1 is rotated. Is performed by pressing them in a direction approaching each other via a slide mechanism. The processed sphere 3 is returned to the conveyor 5 via the exit chute 7.
[0005]
[Problems to be solved by the invention]
Tens of thousands of spheres 3 accommodated on the conveyor 5 at a time are managed as “one lot”.
However, the lot amount processed in the final polishing step that determines the final sphere accuracy of the sphere 3 is usually different for each lot for various reasons.
[0006]
On the other hand, the processing conditions in the final polishing process are currently not numerically controlled, and are largely dependent on the skill of the operator. Therefore, the adjustment of the processing conditions corresponding to the variation in the lot amount is not clear, and the final sphere accuracy is not stable.
[0007]
Up to the sphere accuracy G3 class specified by JIS can be processed by the above-mentioned processing method, but the required accuracy for ball bearings used in recent computer-related equipment has become stricter. There is a problem that defects occur.
[0008]
Accordingly, an object of the present invention is to provide a sphere polishing method capable of stabilizing the final processing accuracy by constantly changing the processing conditions for the sphere even if the lot changes and the processing quantity varies from lot to lot.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the sphere polishing method of the present invention examines the lot amount to be processed in advance, and based on this, the average polishing amount per time (the amount of decrease in the sphere diameter per pass of the polishing circuit ( Each parameter is set before processing or during processing so that an average value of nm / pass) is kept at a predetermined value.
[0010]
Therefore, when conditions such as the sharpness of the grindstone and the lapping liquid supplied between the disc bodies may be considered to be constant, each parameter is set so that the machining pressure acting on one sphere is constant. Further, when these conditions change, it is more preferable to correct the setting conditions of each parameter based on the change in the polishing amount per time for each lot.
[0011]
【Example】
A first embodiment according to the present invention will be described.
The structure of the polishing apparatus according to this example is shown in FIGS. Here, FIG. 2 is a perspective view of a main part of the sphere polishing apparatus, FIG. 3 is an overall configuration diagram of the sphere polishing apparatus including the main part of FIG. 1, and FIG. 4 is an enlarged main part of the rotary conveyor in FIG. FIG.
[0012]
In FIG. 2, the dimensions of the cross-sectional shape of each of the rotating disk body 1 that is rotated by a disk body rotating mechanism (not shown) and the stationary stationary disk body 2 that is positioned coaxially and opposed to the rotating disk body 1 are polished. A plurality of annular grooves (ball grooves) 4 approximating the radius of curvature of the sphere 3 to be processed are provided concentrically. The annular groove 4 of the rotating disk body 1 and the annular groove 4 of the fixed disk body 2 are opposed to each other, and each pair of opposed annular grooves 4 constitutes one of the polishing circuits so that the sphere 3 is polished. It is configured.
Further, a slide guide mechanism (not shown) that slides and guides one of the fixed platen 2 and the rotary platen 1 and a later-described pressing mechanism (first) that pushes one of the plates toward the other platen. 3) in FIG. Polishing is performed by continuously supplying the workpiece sphere 3 to the polishing circuit and operating the pressing mechanism while rotating the rotating disk 1.
[0013]
The carousel 5 includes an outer wall 5a and a rotating part 5b, in which a sphere 3 of a lot to be processed at a time is accommodated. The rotating section 5b of the rotary conveyor 5 is rotationally driven via a speed reduction mechanism 5e by a drive motor 5d built in the lower part of the outer wall 5a. The rotation control of the drive motor 5d is performed by a control unit 15 described later. Between the fixed platen body 2 and the rotary conveyor 5, there are provided an inlet chute 6 for sending the spheres 3 in the rotary conveyor 5 to the polishing circuit, and an outlet chute 7 for returning the spheres 3 polished in the polishing circuit to the rotary conveyor 5. It has been.
[0014]
As shown in FIG. 2, a rotating shaft 12 supported by a pair of rolling bearings 11 is fixed to the rotating disk body 1, and the rotating shaft 12 is rotated by a drive motor 14 via a belt transmission device 13. Is done. The rotation of the drive motor 14 is controlled by the control unit 15. On the other hand, the fixed platen body 2 is connected to a pressurizing cylinder mechanism 16 as a pressing mechanism, and the pressurizing cylinder mechanism 16 is a hydraulic circuit for adjusting the pressing force of the fixed platen body 2 to the rotating platen body 1. 30. The hydraulic circuit 30 includes a direction switching valve 17, a proportional electromagnetic control valve mechanism 20, and an oil pump 21. Each port of the direction switching valve 17 is connected to the pipelines 18 a and 18 b connected to each port of the pressurizing cylinder mechanism 16. Further, the ends of the pipes 18 a and 18 b are connected to the oil tank 19. By adjusting the supply pressure of oil to each port of the pressurizing cylinder mechanism 16 by the proportional electromagnetic control valve mechanism 20, the pressing force of the fixed platen body 2 against the rotary platen body 1 is adjusted.
[0015]
Moreover, as shown to Fig.4 (a), the uniform board 8 is provided in the inner side upper part of the outer wall part 5a of the rotary conveyor 5, and the lower part is made into space. The uniform plate 8 includes a plate-like portion 8a, a fixing screw 8b for fixing the plate-like portion 8a to the outer wall portion, and a fixing member 8c. The longitudinal direction of the plate-like member 8a coincides with the radial direction of the rotary conveyor 5. The plate surface is perpendicular to the bottom surface of the rotary conveyor 5. The installation position of the uniform plate 8 is an arbitrary position closer to the exit chute 7 than the entrance chute 6 of the rotary conveyor 5, and the installation height is determined by the amount of balls, the volume of the rotary conveyor, and the cross-sectional shape.
By providing such a uniform plate, as shown in FIG. 4B, the height of the balls 3 accommodated in the conveyor 5 and sent in the direction of the arrow X in FIG. 2 can be made constant, It is possible to make the inflow amount per unit time of the balls 3 flowing from the conveyor 5 into the polishing circuit of the rotating disk body 1 and the fixed disk body 2 uniform. In general, when the ball has a small diameter, the weight of one ball is light, and when the conveyor or the ball is wet with the lap liquid, the lap liquid is viscous, and therefore the height of the ball is likely to be uneven. However, according to the configuration of the present embodiment, even when the ball 3 has a small diameter, the height of the ball can be made uniform.
[0016]
In the present embodiment, the processing conditions of the balls are changed by changing the pressing force of the fixed platen body 2 by the pressure cylinder mechanism 16, the rotation speed of the conveyor 5, and the rotation number of the rotary platen 1 according to the change in the lot quantity. Try to align. This one-lot polishing process has three stages of roughing, intermediate finishing, and finishing, and processing pressure and rotation to obtain accuracy in the processing speed and diameter suitable for each stage. The disk speed and conveyor speed are adjusted. Specifically, paying attention to the relationship between the lot quantity S and the average value N of the number of balls 3 between the fixed platen 1 and the rotary platen 2 (hereinafter referred to as “polishing circuit”) at a certain moment. , The specifications are controlled so that the force p applied to one ball is constant even if S changes.
[0017]
Here, the probability F that one ball at a certain moment is in the polishing circuit is expressed by the following equation (1).
F = (2k / D) / (C + (2k / D)) (1)
In this equation, D is the number of rotations per minute (rpm) of the rotating disk body, C is the time (minute / rotation) required for one rotation of the conveyor 5, and k is (in the polishing circuit, inlet chute 6 and outlet chute). (Average value of the lengths of the plurality of grooves excluding the notch portion for 7) / (average diameter of the plurality of grooves of the polishing circuit × circumference ratio) (hereinafter, k is referred to as “effective groove length ratio”) It is.
Considering that C is sufficiently larger than D, equation (1) is
F = 2k / (D × C) (2)
It becomes.
On the other hand, the number N of balls in the polishing circuit can be expressed as follows according to the lot quantity S and the probability F in the polishing circuit.
N = F × S (3)
This equation is obtained from (2)
N = (2k × S) / (D × C) (4)
It becomes.
[0018]
Therefore, if the pressing force applied to the fixed platen body 2 by the pressing mechanism 16 is P, the force p applied to one ball is obtained by dividing the force applied to all the balls 3 in the polishing circuit by the pressing mechanism 16 by the number of balls. From the equation (4), p can be expressed by the following equation.
p = P / N = (P × D × C) / (2k × S) (5)
Therefore, p can theoretically be adjusted by changing P, D, and C accordingly even if S changes from lot to lot.
[0019]
In the present embodiment, in order to achieve a preset force p (kgf / piece) applied to one ball, the pressing force P by the pressing mechanism is controlled in accordance with the change in the lot quantity S. ing.
[0020]
Specifically, the effective groove length ratio k of the fixed disk is k = 0.875,
The hydraulic force is adjusted by opening and closing the manual valve.² In the spherical polishing apparatus generated by
When the first lot is final polished under the following conditions:
Diameter of steel ball (ball): 2mm
Weight per unit volume: 7.8 × 10^-6kg / mm^Three
Standard lot weight W: 9.8 kg
Standard rotating disk speed D: 20 rpm
Standard conveyor speed C: 15 min / rev
Standard processing time: 20 hrs (80 pass)
It is. The standard processing time means the total processing time of rough processing, intermediate finishing processing, and finishing processing.
The lot quantity S in this case is
S = 9.8 × 1,000,000 / 32.7≈300,000,
The number N of spheres that receive the processing pressure P is obtained from the equation (4) (N = (2k × S) / (D × C))
N = (2 × 0.875 × 300,000) / (20 × 15) = 1750
Therefore, the processing pressure p applied per ball, that is,
Standard roughing pressure: 200 gf / piece
Standard finishing pressure: 150 gf / piece
Standard finishing processing pressure: 100 gf / piece
The processing pressure P that achieves the following equation (5) (p = P / N):
Standard roughing pressure: 350 kgf (11.7 kgf / cm² )
Standard finishing machining pressure: 263 kgf (8.8 kgf / cm² )
Standard finishing processing pressure: 175 kgf (5.8 kgf / cm² )
It becomes. Therefore, in the first lot, the gauge pressure of the hydraulic cylinder is 11.7 kgf / cm in the initial state.² 8.8kgf / cm after roughing² Furthermore, 5.8kgf / cm after finishing the finishing process² Processing is performed by adjusting the valve. In this way, when the pressurizing cylinder mechanism 16 and the hydraulic circuit 30 are adjusted to complete the processing for one lot, the processing for the next lot is started.
[0021]
Therefore, it is assumed that the lot weight of the next processing lot is 8.0 kg. In this case, by changing only the processing pressure P ′ as follows, the force p ′ applied to each ball is made equal to the force p applied to each ball of the first lot. Can do. That is,
S ′ = 8 × 1,000,000 / 32.7 = 2245 thousand,
N ′ = (2 × 0.875 × 245,000) / (20 × 15) = 1430
Therefore, the processing pressure P ′ for making the processing pressure p applied to one ball equal to the case where the lot weight is 9.8 kg at the standard rough processing pressure, the standard medium finishing processing pressure, and the standard finishing processing pressure. From Equation (5)
Roughing pressure: 9.5 kgf / cm²
Medium finishing processing pressure: 7.2 kgf / cm²
Finishing pressure: 4.8 kgf / cm²
It becomes.
Therefore, the gauge pressure of the hydraulic cylinder is 9.5 kgf / cm in the initial state.² To 7.2 kgf / cm after roughing² Furthermore, 4.8kgf / cm after finishing the intermediate finishing² When processing with the valve adjusted, the processing pressure applied to each ball is the same in the initial lot and the next lot, so the finishing dimensions of the balls in both lots ( Average value).
[0022]
Below, the modification of a present Example is shown.
In the example of FIG. 3, the pressure cylinder mechanism 16 as a pressing mechanism is provided on the fixed platen body 2 side, but may be provided on the rotating platen body 1 side. Further, the processing may be two steps or one step.
[0023]
The installation position of the uniform plate 8 is a position away from the exit chute 7 in order to prevent the balls from overflowing from the rotary conveyor 5 due to the presence of the uniform plate 8 when the thickness and amount of the balls on the conveyor vary greatly. It is preferable to install in. Further, when the variation in the thickness and amount of the balls on the conveyor is small, the uniform plate 8 can be installed at a position closer to the outlet chute 7. Furthermore, you may install in the outer wall part 5a so that the plate-shaped member 8a can move along the outer wall part 5a of a rotary conveyor.
[0024]
Further, in FIG. 4A, a uniform plate 8 is provided on the inner upper portion of the outer wall 5a of the rotary conveyor 5 to make the ball height uniform, but as shown in FIG. 4C, the rotary conveyor The same effect can be obtained by connecting the hollow member 108 to the five outlet chutes 7 and regulating the amount of the ball discharged from the conveyor 5. The shape and installation position of the hollow member are determined by the amount of balls, the volume of the rotary conveyor, and the cross-sectional shape.
[0025]
Moreover, you may convey a ball | bowl with tubular members, such as a vinyl hose and a pipe pipe, instead of the entrance chute 6 and the exit chute 7 of a present Example. In this case, the conveyance amount of the ball is adjusted so that there is a margin that the ball always fluctuates up and down in the tubular member. Thereby, it is possible to make the height of the balls in the rotary conveyor 5 uniform.
[0026]
Further, instead of the uniform plate of FIG. 4A, as shown in FIG. 4D, a skewer-like member 32 may be provided on the outer wall portion 5a of the conveyor 5 via a support member 30. The skewer-shaped member 32 has a tapered diameter, and is provided perpendicular to the bottom surface so that the tip on the narrow side faces the bottom surface of the conveyor. Two skewer-shaped members 32 are arranged on the conveyor, and as shown in FIG. 4 (e), each skewer-shaped member 32 is disposed on each of the two support members 30 provided in the radial direction of the conveyor. The distance from the center of the conveyor is different. The skewer-shaped member 32 is preferably made of bamboo, but may be any material that does not damage the ball.
[0027]
When the skewer-like member is arranged in this manner, the ball on the conveyor 5 has a small height on the conveyor 5, so that the ball passes through the narrow part of the skewer-like member. Becomes smaller. On the other hand, since the height of the ball on the conveyor is high in the portion where the amount of balls is large on the conveyor 5, the ball passes through the thick portion of the skewer member, and the resistance to the ball increases. Accordingly, the movement of the ball is fast in the portion where the number of balls is high, and the movement of the ball is slow in the portion where the number of balls is large.
[0028]
Moreover, you may combine a uniform plate, a skewer-like member, and a tubular member.
Further, the number and thickness of the skewer members are preferably changed according to the amount and size of the balls.
[0029]
Due to the action of the uniform plate 8, the hollow member 108, or the skewer-like member 32, when the rotational speeds of the rotating disk body 1 and the rotary conveyor 5 are constant, the number of balls supplied per hour to the polishing circuit is changed. Therefore, the difference in the finishing dimension of each ball in the lot can be made smaller than before. By combining this action with the effects of the first embodiment, the ball dimensions between lots and within lots are maintained uniformly with high accuracy.
[0030]
Next, a second embodiment will be described.
In the present embodiment, as in the first embodiment, the pressing force P by the pressing mechanism is controlled according to the change in the lot amount S, but a computer control system as shown in FIG. Is different. Further, like the Japanese Patent Application No. 9-87220, the bearing for rotating and supporting the rotating disk body 1 is an oil hydrostatic rotary bearing, and the slide guide mechanism is an oil hydrostatic guide.
[0031]
A computer control system 50 shown in FIG. 5 includes a control unit 52, and the control unit 52 includes a computer unit 54, a motor controller 56, and a hydraulic control unit 58.
[0032]
The computer unit 54 includes a central processing unit (CPU) 60, a memory unit 62, a calculation unit 64, a data input unit 66, and a parallel I / O board 68. The CPU 60 follows the data input from the data input unit 66. Data is mutually exchanged between the memory unit 62, the calculation unit 64, and the parallel I / O board 68. The computer unit 54 is connected to the motor controller 56 and the hydraulic pressure control unit 58 via the parallel I / O board 68, and controls these operations.
[0033]
The motor controller 56 is connected to the drive motor 14 for the rotating disk body 1 and the drive motor 5 d for the rotary conveyor 5, and controls these drive motors based on signals from the computer unit 54.
The hydraulic control unit 58 is connected to the proportional electromagnetic control valve mechanism 20 and controls the proportional electromagnetic control valve mechanism 20 based on a signal from the computer unit 54.
[0034]
Specifically, the computer control system 50 operates as follows.
Parameters necessary for setting machining conditions are input from the data input unit 66 (for example, a keyboard). The lot weight W is input every time the lot changes, but other conditions do not need to be input thereafter if they are input when the initial lot is processed. If the lot quantity S is known, the lot quantity S is input instead of the lot weight W. The other conditions here include the diameter of the steel ball and the weight per unit volume (not required when S is directly input), the rotational speed D (rpm) of the rotating disk body per unit time, and one rotation of the rotating conveyor. Time C (min / rev) required for each step (forces p1, p2, p3 (gf / piece) applied to each ball corresponding to each step (roughing, intermediate finishing, finishing) and the ball in the polishing circuit in each step This is the number of passes (number of conveyor rotations or number of passes) or processing time. The effective groove length ratio k is a fixed value determined by the shape of the fixed platen and is already incorporated in the control program.
[0035]
Similarly to the case of the first embodiment, a program for calculating the machining pressure P in each process is stored in the memory unit 62 in advance based on the above input value, and the calculation unit 64 performs the calculation using this program. Based on the result, the hydraulic control unit 58 is controlled. The input values of the rotation speeds of the conveyor and the rotating disk are passed to the motor controller.
[0036]
As described above, the apparatus according to the present embodiment has a static pressure rotary bearing and a static pressure slide, and each processing parameter can be set in advance by the control function of the computer system.
Other configurations and effects are the same as those of the first embodiment.
[0037]
In this equipment, when the first lot is subjected to final polishing under the following conditions:
Diameter of steel ball (ball): 1/16 inch
Weight per unit volume: 7.8 × 10^-6kg / mm^Three
Standard lot weight W: 10kg
Standard rotating disk speed D: 40 rpm
Standard conveyor speed C: 12 min / rev
Standard processing time: 20 hrs (100 pass)
Lot quantity S is
S = 10 × 1,000,000 / 16.3≈614,000,
The number N of spheres that receive the processing pressure P is obtained from the equation (4) (N = (2k × S) / (D × C))
N = (2 × 0.875 × 614,000) / (40 × 12) = 2240
Therefore, the processing pressure p applied per ball, that is,
Standard roughing pressure: 150 gf / piece
Standard finishing pressure: 100 gf / piece
Standard finishing processing pressure: 60 gf / piece
From the formula (5) (p = P / N), the processing pressure P to achieve
Standard roughing pressure: 336kgf
Standard finishing pressure: 224kgf
Standard finishing processing pressure: 134kgf
It becomes. This series of calculations is performed in the calculation unit 64 by the program prepared in advance as described above.
[0038]
When the next processing lot weight is 9 kg, when the lot weight W ′ is input on the initial setting screen of the computer system in FIG. 5, the number of balls N ′ receiving the lot amount S ′ and the processing pressure P is calculated in the same manner as above. Calculated by the unit 64. Further, the processing pressure p applied to each ball, that is, the same standard rough processing pressure, the standard finishing processing pressure, and the processing pressure P ′ for achieving the standard finishing processing pressure as described above are calculated by the calculation unit 64 using the program. It is calculated as follows.
Roughing pressure: 302kgf
Medium finishing processing pressure: 201kgf
Finishing pressure: 121kgf
Therefore, in the second embodiment, control is easier than in the first embodiment in which the pressure cylinder mechanism 16 and the hydraulic circuit 30 are adjusted.
[0039]
Next, a third embodiment will be described. The present embodiment also has the same configuration as the second embodiment, but in this embodiment, by controlling the time C (conveyor speed) per conveyor rotation and the processing time in accordance with the change in the lot quantity. Even if the lot changes, the forces p1, p2, and p3 applied to each ball corresponding to the roughing, intermediate finishing, and finishing processes are kept constant.
[0040]
That is, S (or W) is input to the data input unit 66 for each lot, and as the other conditions only for the first time, the diameter of the steel ball and the weight per unit volume, the rotational speed D per unit time of the rotating disk body, The processing pressure P (kgf), rough processing, intermediate finishing, and forces p1, p2, and p3 applied to each ball corresponding to each process are input.
[0041]
Specifically, the processing conditions of the first lot (steel ball diameter, weight per unit volume, standard lot weight, standard rotating disk speed, standard conveyor speed and standard processing time) are the same as in the second embodiment. In some cases, when the standard processing pressure is 336 kgf, the lot quantity S ″ of the next processing lot is
S ″ = (9 × 1,000,000) /16.3≈552,000,
Is the processing pressure p per ball, that is,
Standard roughing pressure: 150 gf / piece
Standard finishing pressure: 100 gf / piece
Standard finishing processing pressure: 60 gf / piece
The conveyor speed C ″ for achieving the following is rough processing, intermediate finishing by the arithmetic unit 64 based on a program prepared in advance from Equation (5) (p = (P × D × C) / (2k × S)). The one corresponding to each process of the finish is calculated, automatically by the computer control system,
Standard roughing: 10.8 min / rev
Standard finishing process: 7.2 min / rev
Standard finishing: 4.3 min / rev
Changed to
[0042]
Further, since the number of times the ball passes through the polishing circuit (100 pass) is constant, the processing time is automatically changed as the conveyor speed is changed.
That is, if the standard roughing, standard finishing, and standard finishing are 40, 40, and 20 passes (total of 100 passes),
Standard roughing: 10.8 min x 40 = 432 min
Standard finishing process: 7.2 min × 40 = 288 min
Standard finishing processing: 4.3 min × 20 = 86 min
The total is 806 min = 13 hrs 26 min. (If the conveyor speed is constant at 12 min / rev, it will be 20 hrs at 100 pass)
[0043]
Although the standard processing pressure P is constant in each process, this may be changed for each process, and the conveyor speed may be constant regardless of the process. For example, in the above example, similarly to the second embodiment, when P1 = 336 kgf, P2 = 224 kgf, P3 = 134 kgf and the conveyor speed of the first lot is 12 min / rev, in the next lot, each process is 10.8 min / rev is set, and the processing time is 18 hours at 100 pass.
[0044]
Next, a fourth embodiment will be described.
In this embodiment, in the third embodiment, when the groove of the rotating disk body or the fixed disk body is worn by processing and the polishing efficiency is lowered, in addition to the change of the conveyor speed based on the formula (5), the processing By changing the pressure P, by correcting the processing pressure p applied to each ball, the average polishing amount per time (the average value of the decrease in the diameter of the sphere per pass of the polishing circuit) is made constant. Keep within the range.
[0045]
Specifically, in the third embodiment, for each lot, the spheres before and after processing were sampled and the diameter was measured. As a result, the average polishing amount at the time of initial lot processing was 10 nm / pass, and the average polishing of the next lot The amount was 9 nm / pass. Based on this result, in the next lot, when the processing pressure P was set to be increased by 20%, the average polishing amount of this lot was 10 nm / pass. This is achieved, for example, by examining the relationship between the change in the average polishing amount and the processing pressure in advance and preparing a table thereof.
[0046]
The table is stored in the memory 62, and the average polishing amount of each of the previous two lots is input to the data input unit 66, and the correction value of P is calculated from the input value and the table. It is also possible to prepare a program for calculating and to automatically change P.
In this embodiment, the third embodiment, i.e., the embodiment in which p is kept constant by changing the conveyor rotation speed, is further corrected to p to achieve a uniform polishing amount. Needless to say, it may be combined with the first embodiment or the second embodiment.
[0047]
【The invention's effect】
As described in detail above, according to the sphere polishing method of the present invention, when the processing quantity varies from lot to lot, even if the lot changes, the force p applied to each sphere is constant, and the processing conditions for the sphere are constant. Becomes constant, the average polishing amount per pass (per pass of the polishing circuit) can be made constant, and the final processing accuracy can be stabilized. In addition, by measuring the processing lot amount in advance and performing simple calculations or simple inputs, even if the processing amount changes for each lot, constant processing can be performed at all times, and the processing accuracy of the sphere is stable. Can be achieved.
[0048]
Furthermore, when conditions, such as the sharpness of a grindstone, change, based on the result of the previous two lots, the processing conditions can be corrected to achieve further stability.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a conventional spherical polishing apparatus.
FIG. 2 is a perspective view of a main part in a conventional spherical polishing apparatus.
FIG. 3 is an overall configuration diagram of a conventional sphere polishing apparatus including the main part of FIG. 2;
FIG. 4 is a diagram showing an example of means for making the height of a ball uniform.
FIG. 5 is a block diagram showing a computer control system of a second embodiment.
[Explanation of symbols]
1 Turntable
2 Fixed platen
3 Sphere
4 annular groove
5 Rotating conveyor
11 Rolling bearing
12 Rotating shaft
13 Belt drive
14 Drive motor
16 Pressure cylinder mechanism
30 Hydraulic circuit
C Time required for one rotation of the conveyor
D Number of revolutions per minute of rotating disc
k Effective groove length ratio
N Number of balls in the polishing circuit
P pressing force
p Force on one ball
S lot quantity

Claims (1)

Two disc bodies that are opposed to each other at a predetermined interval and can hold a sphere to be polished between the opposing surfaces;
A rotation mechanism for rotating at least one of the two plate bodies;
A conveyor that accommodates and rotates a plurality of the spheres to be supplied to the two board bodies ;
A pressing mechanism that presses one of the two board bodies to the other side;
Rotating at least one of the two disk bodies by the rotating mechanism in a state where the sphere is sandwiched between opposing surfaces of the two disk bodies;
In the sphere polishing method of polishing the sphere while pressing either one of the two disk bodies to the other side by the pressing mechanism,
Even if the number of spheres varies from lot to lot, the pressing force applied by the pressing mechanism, the time required to rotate the conveyor, and the number of rotations of the board are adjusted so that the force applied to one sphere is constant. Thus, the spherical polishing method is characterized in that the average polishing amount per time of the sphere is adjusted within a certain range .

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