JP7003554B2 - Sphere polishing device and sphere polishing method - Google Patents

Description

The present invention relates to a sphere polishing apparatus and a sphere polishing method.

Patent Document 1 describes a sphere polishing device that polishes a sphere. This spherical polishing device is arranged so as to face the first polishing machine having an annular first polishing groove so that the central axis is coaxial with the first polishing machine, and is relatively movable in the direction of the central axis and around the central axis. A second polishing machine having an annular second polishing groove facing the first polishing groove is provided on the surface facing the first polishing machine so as to be relatively rotatable.

This sphere polishing device sandwiches a sphere between the first polishing groove and the second polishing groove, moves the first polishing machine and the second polishing machine relative to each other and rotates them relative to each other, and moves relative to each other when a predetermined load is reached. It is stopped, and spark-out is performed for a predetermined time to stop the relative rotation. In the polishing process, even if the first polishing machine and the second polishing machine are moved relative to each other, the polishing amount according to the set value may not be obtained due to insufficient rigidity of the spherical polishing machine, the first polishing machine, and the second polishing machine. .. Therefore, in the spark-out, that is, at the final stage of the polishing process, the relative movement of the first polishing machine and the second polishing machine is stopped, and only the relative rotation is performed to bring the polishing amount closer to a predetermined value.

Japanese Unexamined Patent Publication No. 2016-203360

In the above-mentioned spherical polishing apparatus, the polishing process is performed while increasing the load, and when a predetermined load is reached, spark-out is performed to complete the polishing process. However, even if the processing conditions of the polishing process, that is, the moving speed and rotation speed of the first polishing machine and the second polishing machine, the starting load of spark-out, etc. are the same, the processing accuracy of the sphere, especially the sphericity, is due to disturbance or the like. May vary.

An object of the present invention is to provide a sphere polishing device and a sphere polishing method capable of improving the processing accuracy of a sphere.

(Sphere polishing device and sphere polishing method)
The first sphere polishing device of the present invention is arranged to face each other and is capable of sandwiching a sphere between facing surfaces, and is capable of relative movement in a plane parallel to the facing surface in order to polish the sphere. A pair of polishing machines capable of relative movement in a direction perpendicular to the facing surface and the pair of polishing machines are relatively moved in a plane parallel to the facing surface and relatively moved in a direction perpendicular to the facing surface. A load sensor that measures the load generated on the sphere that is sandwiched between the facing surfaces due to the relative movement of the moving device and the pair of polishing machines by the moving device, and the said sphere during polishing. The cumulative work amount calculation unit that calculates the work amount obtained from the load measured by the load sensor and the rolling distance of the sphere over time, and obtains the cumulative work amount that correlates with the processing accuracy of the sphere, and the cumulative work amount calculation. A polishing control unit that controls the moving device to perform polishing processing of the sphere based on the cumulative work amount by the unit is provided.
The second sphere polishing device of the present invention is arranged to face each other and can hold the sphere between the facing surfaces, and can move relative to the facing surface in a plane parallel to the facing surface in order to polish the sphere. A pair of polishing machines capable of relative movement in a direction perpendicular to the facing surface and the pair of polishing machines are relatively moved in a plane parallel to the facing surface and relatively moved in a direction perpendicular to the facing surface. A load sensor that measures the load generated on the sphere that is sandwiched between the facing surfaces due to the relative movement of the moving device and the pair of polishing spheres by the moving device, and the said sphere during polishing. A cumulative load calculation unit that measures the load measured by a load sensor over time and calculates a cumulative load that correlates with the machining accuracy of the sphere, a database that associates the cumulative load with the machining parameters of the sphere, and the above. The moving device is controlled based on a storage unit that stores a database that associates the processing parameters of the sphere with the processing accuracy of the sphere, the cumulative load by the cumulative load calculation unit, and the database stored in the storage unit. A polishing control unit for polishing the sphere is provided.

The first sphere polishing method of the present invention is a sphere polishing method using the first sphere polishing device, wherein the sphere polishing device is arranged to face each other and can hold the sphere between the facing surfaces. A pair of polishing machines that can move relative to the facing surface in a plane parallel to the facing surface and can move relative to the direction perpendicular to the facing surface for polishing the sphere, and the pair of polishing machines to the facing surface. It is sandwiched between the facing surfaces by the relative movement of the pair of polishing machines by the moving device and the moving device that moves relative to each other in a plane parallel to the facing surface and moves relative to the facing surface in a direction perpendicular to the facing surface. The sphere polishing method includes a load sensor for measuring the load generated on the sphere, and the sphere polishing method measures the rolling distance of the sphere based on the relative movement speed in a plane parallel to the facing surface of the pair of polishing machines. The calculation step of the rolling distance, the work amount obtained from the load measured by the load sensor during the polishing process of the sphere and the rolling distance of the sphere are calculated over time, and the cumulative value correlates with the processing accuracy of the sphere. It includes a cumulative work amount calculation step for obtaining a work amount and a polishing control step for controlling the moving device to polish the sphere based on the cumulative work amount obtained in the cumulative work amount calculation step.
The second sphere polishing method of the present invention is a sphere polishing method using the second sphere polishing device, wherein the sphere polishing device is arranged to face each other and can hold the sphere between the facing surfaces. A pair of polishing machines that can move relative to the facing surface in a plane parallel to the facing surface and can move relative to the direction perpendicular to the facing surface for polishing the sphere, and the pair of polishing machines to the facing surface. It is sandwiched between the facing surfaces by the relative movement of the pair of polishing machines by the moving device and the moving device that moves relative to each other in a plane parallel to the facing surface and moves relative to the facing surface in a direction perpendicular to the facing surface. The sphere polishing method includes a load sensor for measuring the load generated on the sphere, and the sphere polishing method measures the load measured by the load sensor during polishing of the sphere over time and has a machining accuracy of the sphere. A cumulative load calculation step for calculating a cumulative load correlating with the above, and a polishing control step for controlling the moving device to polish the sphere based on the cumulative load obtained in the cumulative load calculation step are provided. The sphere polishing device includes a storage unit that stores a database that associates the cumulative load with the processing parameters of the sphere and a database that associates the processing parameters of the sphere with the processing accuracy of the sphere, and the polishing control step. Controls the moving device based on the cumulative load and the database to polish the sphere.

As a result of diligent research on the polishing process, the present inventor has found that the cumulative work amount or the cumulative load of the polishing process of the sphere correlates with the processing accuracy of the sphere. Therefore, according to the sphere polishing device of the present invention or the sphere polishing method of the present invention, by constantly monitoring the cumulative work amount or the cumulative load of the sphere polishing process, it is possible to polish the sphere to the target sphericity.

It is a figure which shows the structure of the spherical polishing apparatus of this embodiment. It is a figure which shows the structure of the control device of the spherical polishing apparatus of FIG. It is a flowchart for demonstrating the sphere polishing method by the control device of FIG. It is a figure which shows the time-dependent change of the descending position of the 2nd polishing machine in the polishing process of a sphere. It is a figure which shows the time-dependent change of the load applied to a sphere in the polishing process of a sphere. It is a figure which shows the time-dependent change of the cumulative work amount in the polishing process of a sphere. It is a figure which shows the relationship between the sphericity of a sphere, and the polishing amount of a sphere. It is a figure which shows the relationship between the polishing amount of a sphere, and the cumulative work amount in the polishing process of a sphere. It is a figure which shows the relationship between the sphericity of a sphere, and the cumulative work amount in the polishing process of a sphere. It is a figure which shows the relationship between the rotation speed of the 1st polishing machine and the rotation speed of the 2nd polishing machine. It is a figure which shows the relationship of another example of the rotation speed of the 1st polishing machine and the rotation speed of the 2nd polishing machine. It is a figure which shows the structure of the control apparatus of another example of the spherical polishing apparatus of FIG. It is a flowchart for demonstrating the sphere polishing method by the control device of FIG. It is sectional drawing in the axial direction of the cage which holds a sphere and a sensor unit. FIG. 15 is a cross-sectional view taken along the line XVI-XVI of FIG. It is a figure seen from the XV direction of the cage of FIG.

(1. Configuration of spherical polishing device)
The configuration of the spherical polishing apparatus of this embodiment will be described with reference to the drawings. As shown in FIG. 1, the spherical polishing device 1 includes a base 11, a column 12, a first moving body 13, a second moving body 14, a vertical drive mechanism 15 (moving device), a load sensor 16, and a control device 18 (FIG. 1). 2).

The base 11 is installed on the floor surface and has a vertical through hole 11a in the center. The column 12 is fixed to the upper surface of the base 11. Guide rails 12a and 12b extending in the vertical direction are provided on the side surface of the column 12.

The first moving body 13 is arranged on the upper surface of the base 11 and in the through hole 11a. The first moving body 13 includes a first main body portion 21, a first polishing machine support 22, a first polishing machine 23 as a first board, a first static pressure bearing 24, and a first motor 25 (moving device).

The first main body portion 21 is formed in a disk shape having a central hole 21a. The first main body portion 21 is fixed to the upper surface of the base 11 so that the central hole 21a is located coaxially with the through hole 11a of the base 11. The central axis of the central hole 21a is L1 and coincides with the vertical axis direction.

The first polishing machine support 22 is rotatably provided around the central axis L1 with respect to the first main body portion 21. The first polishing machine support 22 includes a shaft portion 22a penetrating the central hole 21a of the first main body portion 21, and disk-shaped flange portions 22b, 22c facing the upper and lower surfaces of the first main body portion 21.

The first polishing machine 23 is integrally fixed to the upper surface of the upper flange portion 22b of the first polishing machine support 22. That is, the first polishing machine 23 is rotatably provided around the central axis L1 with respect to the first main body portion 21. The first polishing machine 23 is formed in an annular shape.

Further, the first polishing machine 23 has a first polishing groove 23a formed in an annular shape around the central axis L1 on one surface (upper surface). The cross-sectional shape of the first polishing groove 23a is formed in an arc concave shape. The first polishing groove 23a grinds the sphere 2 to be polished in cooperation with the second polishing groove 33a described later. As a result, the plurality of spheres 2 can be efficiently polished.

The first static pressure bearing 24 has a first polishing machine support 22 held by the first main body 21 and integrally fixed to the first polishing machine 23 in the radial direction and thrust with respect to the first main body 21. Support in the direction.

Specifically, the first static pressure bearing 24 includes a radial bearing 24a that is held in the central hole 21a of the first main body portion 21 and is supported by fluid pressure on the outer peripheral surface of the shaft portion 22a. Further, the first static pressure bearing 24 includes thrust bearings 24b, 24c that are held on the upper surface and the lower surface of the first main body portion 21 and are supported by the fluid pressure with respect to the flange portions 22b, 22c.

The fluid supplied to the first hydrostatic bearing 24 is supplied from a common fluid supply source and is branched into a radial bearing 24a and a thrust bearing 24b, 24c. The first hydrostatic bearing 24 further comprises an orifice throttle 24d (see FIG. 2).

The orifice throttle 24d is provided in each of the radial bearings 24a and the thrust bearings 24b and 24c. Here, since the position of the orifice throttle 24d constituting the first static pressure bearing 24 is variable, the fluid pressure is variable. The first motor 25 is supported by the first main body portion 21 and rotationally drives the first polishing machine support 22.

The second moving body 14 is arranged so as to be movable in the vertical direction with respect to the column 12. The second moving body 14 includes a second main body portion 31, a second polishing machine support 32, a second polishing machine 33 as a second board, a second hydrostatic bearing 34, and a second motor 35 (moving device).

The second main body portion 31 is formed in a cylindrical shape, and has central holes 31a and 31b in the lower disk portion and the upper disk portion. The central axis of the central holes 31a and 31b of the second main body 31 is L2, which coincides with the central axis L1 of the central hole 21a of the first main body 21.

The cylindrical portion of the second main body portion 31 is slidably provided on the guide rails 12a and 12b on the side surface of the column 12. That is, the second main body portion 31 can move in the vertical direction with respect to the column 12.

The second polishing machine support 32 is rotatably provided around the central axis L2 with respect to the second main body portion 31. The second polishing machine support 32 has a shaft portion 32a penetrating the central hole 31a of the lower disk portion of the second main body portion 31, and a disk-shaped flange portion facing the lower surface and the upper surface of the lower disk portion of the second main body portion 31. 32b and 32c are provided.

The second polishing machine 33 is integrally fixed to the lower surface of the flange portion 32b on the lower side of the second polishing machine support 32. That is, the second polishing machine 33 is rotatably provided around the central axis L2 with respect to the second main body portion 31. The second polishing machine 33 is formed in an annular shape.

Further, the second polishing machine 33 has a second polishing groove 33a formed in an annular shape around the central axis L2 on one surface (lower surface). The cross-sectional shape of the second polishing groove 33a is formed in an arc concave shape. The second polishing groove 33a polishes the sphere 2 to be polished.

The surface of the second polishing machine 33 on the second polishing groove 33a side faces the surface of the first polishing machine 23 on the first polishing groove 23a side. The annular diameter of the second polishing groove 33a is formed to be the same as the annular diameter of the first polishing groove 23a. Further, the cross-sectional arc diameter of the second polishing groove 33a is formed to have the same diameter as the cross-sectional arc diameter of the first polishing groove 23a.

The second static pressure bearing 34 is held by the lower disk portion of the second main body portion 31, and the second polishing plate support 32 integrally fixed to the second polishing plate 33 is attached to the second main body portion 31. Support in the radial direction and the thrust direction. Specifically, the second static pressure bearing 34 includes a radial bearing 34a that is held in the central hole 31a of the lower disk portion of the second main body portion 31 and is supported by fluid pressure on the outer peripheral surface of the shaft portion 32a.

Further, the second static pressure bearing 34 includes thrust bearings 34b, 34c that are held on the upper surface and the lower surface of the lower disk portion of the second main body portion 31 and are supported by the fluid pressure with respect to the flange portions 32b, 32c.

The fluid supplied to the second hydrostatic bearing 34 is supplied from a common fluid supply source and is branched into the radial bearing 34a and the thrust bearings 34b and 34c. The second hydrostatic bearing 34 further comprises an orifice throttle 34d (see FIG. 2). The orifice throttle 34d is provided in each of the radial bearing 34a and the thrust bearings 34b and 34c.

Here, since the position of the orifice throttle 34d constituting the second static pressure bearing 34 is variable, the fluid pressure is variable. Further, the fluid supply source for supplying the fluid to the second hydrostatic bearing 34 is provided in common with the fluid supply source for supplying the fluid to the first hydrostatic bearing 24. The second motor 35 is supported by the second main body portion 31 and rotationally drives the second polishing machine support 32.

The vertical drive mechanism 15 moves the second main body 31 up and down with respect to the column 12. The vertical drive mechanism 15 has a motor 41 fixed to the upper end of the column 12, a ball screw 42 connected to the output shaft of the motor 41, and the center of the upper disk portion of the second main body 31 screwed to the ball screw 42. A ball screw nut 43 fixed to the hole 31b is provided.

The load sensor 16 is, for example, a load cell, and is arranged between the first main body portion 21 and the base 11. The load sensor 16 measures the load generated between the first polishing machine 23 and the second polishing machine 33, that is, the load applied to the sphere 2.

(2. Configuration of control device)
Next, the configuration of the control device 18 will be described with reference to the drawings. As shown in FIG. 2, the control device 18 includes a rolling distance calculation unit 81, a cumulative work amount calculation unit 82, a polishing control unit 83, a motor control unit 84, a fluid pressure adjustment unit 85, and a storage unit 86. To prepare for.

The rolling distance calculation unit 81 determines the rolling distance of the sphere 2 in the first and second polishing grooves 23a and 33a based on the rotation speeds and the like of the pair of first and second polishing machines 23 and 33 arranged to face each other. calculate. As a result, a device for measuring the rolling distance of the sphere 2 is unnecessary, and an increase in the device cost of the sphere polishing device 1 can be suppressed.

Specifically, the rolling distance calculation unit 81 is the rotation speed N1 of the first and second polishing machines 23 and 33 obtained from the rotation speeds detected from the encoders of the drawings provided in the first and second motors 25 and 35. , N2, the diameter d of the sphere 2 stored in the storage unit 86, the diameters D of the first and second polishing grooves 23a and 33a (both are the same, see FIG. 1), and the sampling time t are set to the following equation (1). By substituting into, the rolling distance S of the sphere 2 in the first and second polishing grooves 23a and 33a is calculated.

The cumulative work amount calculation unit 82 calculates the cumulative work amount of the polishing process based on the rolling distance of the sphere 2 obtained by the rolling distance calculation unit 81. Specifically, the cumulative work amount calculation unit 82 substitutes the detected load G from the load sensor 16 and the rolling distance S of the sphere 2 from the rolling distance calculation unit 81 into the following equation (2) for polishing. Calculate the cumulative work amount W. In the formula (2), ts is the polishing process start time and te is the polishing process end time. The details of the cumulative work amount W of the polishing process will be described later.

The polishing control unit 83 controls the polishing process of the sphere 2 based on the cumulative work amount of the polishing process obtained by the cumulative work amount calculation unit 82. Specifically, the polishing control unit 83 is the processing condition of the polishing process of the current sphere 2 stored in the storage unit 86, that is, the rotation speeds of the first and second polishing machines 23 and 33, and the second polishing machine 33. The descent speed, the start load of spark-out, etc. are read, and the machining control start command according to the above machining conditions is input to the motor control unit 84 to start the polishing process.

Then, the polishing control unit 83 performs the polishing process from the cumulative work amount calculation unit 82 based on the relationship between the sphericity of the current sphere 2 obtained from the database stored in the storage unit 86 and the cumulative work amount of the polishing process. When the cumulative work amount is within the predetermined range, a machining control stop command is input to the motor control unit 84 to stop the polishing process. The details of the database will be described later.

The motor control unit 84 controls each of the motors 25, 35, 41 based on the machining control start command and the machining control stop command from the polishing control unit 83. That is, the motor control unit 84 rotates and drives the first motor 25, so that the first polishing machine 23 rotates. Further, the motor control unit 84 rotates and drives the second motor 35, so that the second polishing machine 33 rotates. Further, the motor control unit 84 rotates and drives the motor 41, so that the second moving body 14 moves up and down.

The fluid pressure adjusting unit 85 adjusts the throttle amounts of the orifice throttles 24d and 34d. By moving the position of the first orifice throttle 24d by the fluid pressure adjusting portion 85, the rigidity of the first static pressure bearing 24 changes. Further, the rigidity of the second static pressure bearing 34 changes when the fluid pressure adjusting unit 85 moves the position of the second orifice throttle 34d.

The first orifice throttle 24d adjusts all the fluid pressures of the radial bearings 24a and the thrust bearings 24b and 24c at the same time. That is, by adjusting the first orifice throttle 24d, the rigidity of the radial bearing 24a and the rigidity of the thrust bearings 24b and 24c are adjusted. At the same time, the moment rigidity of the first hydrostatic bearing 24 is adjusted.

The second orifice throttle 34d adjusts all the fluid pressures of the radial bearings 34a and the thrust bearings 34b and 34c at the same time. That is, by adjusting the second orifice throttle 34d, the rigidity of the radial bearing 34a and the rigidity of the thrust bearings 34b and 34c are adjusted. At the same time, the moment rigidity of the second hydrostatic bearing 34 is adjusted.

By providing the first orifice throttle 24d in each of the radial bearings 24a and the thrust bearings 24b and 24c, the fluid pressures of the radial bearings 24a and the thrust bearings 24b and 24c can be adjusted independently. The same applies to the second orifice throttle 34d.

Further, by making the positions of the first and second orifice throttles 24d and 34d variable, the fluid pressures of the first and second static pressure bearings 24 and 34 are made variable. In addition, the fluid pressure adjusting unit 85 can also adjust the fluid pressure supplied by the fluid supply source to the first and second hydrostatic bearings 24 and 34.

(3. Cumulative work of polishing)
Next, the cumulative work amount of the polishing process will be described with reference to the figure. In the spherical polishing apparatus 1, the first and second polishing machines 23 and 33 are rotated in a plane parallel to the facing surface of the first and second polishing machines 23 and 33, and the second polishing machine 33 is rotated in the first and second polishing machines 33. (Ii) The polishing machines are lowered in a direction perpendicular to the facing surfaces of the polishing machines 23 and 33 (time T1-T2 in FIG. 4), and the polishing process is performed while increasing the load G applied to the sphere 2 (time T1-T2 in FIG. 5). ..

Then, when the load G applied to the sphere 2 reaches the start load Gs of spark-out (time T2 in FIG. 5), the descent of the second polishing machine 33 is stopped (time T2 in FIG. 4), and spark-out is performed for a predetermined time. (Times T2-T3 in FIGS. 4 and 5), the polishing process is completed.

However, as described in the problem, the processing conditions of the polishing process, that is, the rotation speeds of the first and second polishing machines 23 and 33, the descending speed of the second polishing machine 33, the start load of spark-out, and the like are the same. However, the processing accuracy of the sphere 2, particularly the sphericity, may vary due to disturbance or the like.

The inventor has stated that when the above-mentioned polishing conditions are the same, the processing accuracy (sphericity) of the sphere 2 correlates with the processing parameter (polishing amount) of the sphere 2 and the polishing amount of the sphere 2. Found that it correlates with the cumulative workload of the polishing process of the sphere 2. Therefore, there is a correlation between the sphericity of the sphere 2 and the cumulative work amount of the polishing process of the sphere 2.

The cumulative work amount of the polishing process of the sphere 2 is the work amount per unit time, that is, the product of the load per unit time applied to the sphere 2 during the polishing process of the sphere 2 and the rolling distance per unit time of the sphere 2. It is expressed as a value obtained over time from the start of polishing and sequentially added. In the polishing process of the sphere 2 shown in FIGS. 4 and 5, as shown in FIG. 6, the cumulative work amount W of the polishing process of the sphere 2 increases sharply from time T1 to time T2, and from time T2 to time T3. Will gradually increase.

As a specific example of the above correlation, the rotation speeds of the first and second polishing machines 23 and 33 are opposite to each other, and the rotation speed N1 of the first polishing machine 23 and the rotation speed N2 of the second polishing machine 33 are both constant. (See FIG. 10), the relationship between the sphericity C of the sphere 2 and the polishing amount Q of the sphere 2 changes as shown by the solid line in FIG. 7, and the polishing amount Q of the sphere 2 and the polishing amount Q of the sphere 2 are changed. The relationship with the cumulative work amount W of processing changes as shown by the solid line in FIG.

As is clear from FIG. 7, the sphericity C of the sphere 2 deteriorates as the polishing amount Q of the sphere 2 increases. Further, as is clear from FIG. 8, as the cumulative work amount W of the polishing process of the sphere 2 increases, the polishing amount Q of the sphere 2 increases. The relationship between the sphericity C of the sphere 2 and the polishing amount Q of the sphere 2 is obtained from the measured value when the sphere 2 is polished by changing the starting load Gs of the spark out.

From the relationship between the solid line of FIG. 7 and the solid line of FIG. 8, as shown by the solid line of FIG. 9, the relationship between the sphericity C of the sphere 2 and the cumulative work amount W of the polishing process of the sphere 2 can be obtained. Therefore, in order to polish the sphere 2 so that the sphericity C of the sphere 2 is within the predetermined range Ca—Cb, it is necessary to keep the polishing amount Q of the sphere 2 within the predetermined range Qa—Qb.

Then, in order to polish the sphere 2 so that the polishing amount Q of the sphere 2 is within the predetermined range Qa-Qb, it is necessary to keep the cumulative work amount W of the polishing process of the sphere 2 within the predetermined range Wa-Wb. .. That is, in order to polish the sphere 2 so that the sphericity C of the sphere 2 is within the predetermined range Ca-Cb, it is necessary to keep the cumulative work amount W of the polishing process of the sphere 2 within the predetermined range Wa-Wb. be.

Further, as another specific example of the above-mentioned correlation, the rotation directions of the first and second polishing machines 23 and 33 are opposite, and the rotation speed of the second polishing machine 33 has an amplitude between N2max-N2mid-N2min. When the rotation speed N1 of the first polishing machine 23 is constant (see FIG. 11) due to a trapezoidal wavy shape in P, the relationship between the sphericity C of the sphere 2 and the polishing amount Q of the sphere 2 is shown in FIG. It changes as shown by the one-point chain line, and the relationship between the polishing amount Q of the sphere 2 and the cumulative work amount W of the polishing process of the sphere 2 changes as shown by the one-point chain line in FIG.

As is clear from FIG. 7, the sphericity C of the sphere 2 deteriorates as the polishing amount Q of the sphere 2 increases. Further, as is clear from FIG. 8, as the cumulative work amount W of the polishing process of the sphere 2 increases, the polishing amount Q of the sphere 2 increases.

From the relationship between the alternate long and short dash line in FIG. 7 and the alternate long and short dash line in FIG. 8, the relationship between the sphericity C of the sphere 2 and the cumulative work amount W of the polishing process of the sphere 2 can be obtained. can. Therefore, in order to polish the sphere 2 so that the sphericity C of the sphere 2 is within the predetermined range Cc—Cd, it is necessary to keep the polishing amount Q of the sphere 2 within the predetermined range Qc—Qd.

Then, in order to polish the sphere 2 so that the polishing amount Q of the sphere 2 is within the predetermined range Qc-Qd, it is necessary to keep the cumulative work amount W of the polishing process of the sphere 2 within the predetermined range Wc-Wd. .. That is, in order to polish the sphere 2 so that the sphericity C of the sphere 2 is within the predetermined range Cc-Cd, it is necessary to keep the cumulative work amount W of the polishing process of the sphere 2 within the predetermined range Wc-Wd. be.

The data relating the sphericity C of the sphere 2 and the polishing amount Q of the sphere 2 and the data relating the polishing amount Q of the sphere 2 and the cumulative work amount W of the polishing process of the sphere 2 as described above are polishing. It is created under various processing conditions and stored in the storage unit 86 as a database.

This makes it possible to accurately find the optimum cumulative work amount W capable of increasing the sphericity C of various spheres 2. The sphericity C of the sphere 2 and the cumulative work amount W of the polishing process of the sphere 2 may be stored in the storage unit 86 as a database.

(4. Sphere polishing method using a control device)
Next, a method of polishing the sphere 2 by the control device 18 will be described with reference to the drawings. First, the sphere polishing device 1 prepares the sphere 2 so that it can be polished (step S1 in FIG. 3). Specifically, the fluid pressure adjusting unit 85 sets the orifice throttles 24d and 34d so that the fluid pressure of the first and second static pressure bearings 24 and 34 becomes the fluid pressure used when polishing the sphere 2. Set it. Then, the motor control unit 84 drives the motor 41 to move the second moving body 14 upward.

In this state, the operator arranges the plurality of spheres 2 in the first polishing groove 23a of the first polishing machine 23. Subsequently, the motor control unit 84 drives the motor 41 to move the second moving body 14 downward so that the second polishing groove 33a of the second polishing machine 33 comes into contact with the sphere 2.

That is, the sphere 2 is sandwiched between the first polishing machine 23 and the second polishing machine 33 in an annular shape around the central axes L1 and L2. As a result, the sphere 2 can be polished. Then, the operator determines the optimum polishing processing conditions in consideration of the outer diameter and the like of the sphere 2 before and after the polishing processing, and inputs the condition reading command from the input unit of the control device 18.

Next, the polishing control unit 83 starts polishing the sphere 2 (step S2 in FIG. 3, polishing control step). That is, the polishing control unit 83 reads the polishing processing condition corresponding to the input condition reading command from the storage unit 86, and inputs the polishing processing start command to the motor control unit 84.

The motor control unit 84 drives and controls the first motor 25 and the second motor 35 in accordance with the input polishing start command, and rotates the first polishing machine 23 and the second polishing machine 33 at a predetermined rotation speed. The motor 41 is driven and controlled at a low speed to gradually move the second moving body 14 downward, and the sphere 2 is pinched between the first polishing machine 23 and the second polishing machine 33 for polishing. I do.

Then, the rolling distance calculation unit 81 calculates the rolling distance of the sphere 2 in the first and second polishing grooves 23a and 33a based on the rotation speeds of the first and second polishing machines 23 and 33 (Fig.). Step S3 of 3, rolling distance calculation step).

Then, the cumulative work amount calculation unit 82 calculates the cumulative work amount of the polishing process based on the rolling distance of the sphere 2 obtained by the rolling distance calculation unit 81 and the measured load from the load sensor 16 (step S4 in FIG. 3). Cumulative work calculation process).

The polishing control unit 83 determines whether or not the measured load measured by the load sensor 16 has reached the spark-out start load (step S5 in FIG. 3), and if the measured load has not reached the spark-out start load, the step The process returns to S3 and the above process is repeated.

On the other hand, when the measured load reaches the spark-out start load, the motor control unit 84 is instructed to spark-out (step S6 in FIG. 3, polishing control step). Specifically, the motor control unit 84 stops the downward movement of the second moving body 14, and the rotation of the first polishing machine 23 and the rotation of the second polishing machine 33 are kept as they are to approach a predetermined polishing amount. Continue polishing.

Then, the polishing control unit 83 determines whether or not the cumulative work amount of the polishing process obtained by the cumulative work amount calculation unit 82 is within a predetermined range (step S7 in FIG. 3, polishing control step), and performs the polishing process. When the cumulative work amount falls within the predetermined range, the polishing processing stop command is input to the motor control unit 84.

The motor control unit 84 stops the first motor 25 and the second motor 35 to stop the polishing process according to the input polishing process stop command, drives the motor 41, and moves the second moving body 14 to the upper retracted position. (Step S8 in FIG. 3, polishing control step), and all the processes are completed.

As described above, since it was found that the cumulative workload of the polishing process of the sphere 2 has a correlation with the processing accuracy of the sphere 2, that is, the sphericity, the cumulative workload of the polishing process of the sphere 2 is constantly monitored. As a result, the sphere 2 can be polished to a target sphericity.

(5. Configuration of another type of control device)
In the control device 18 described above, the polishing process of the sphere 2 is controlled based on the cumulative work amount in the polishing process of the sphere 2, but the polishing process of the sphere 2 is based on the cumulative load in the polishing process of the sphere 2. It may be configured to control. If the rotation speeds N1 and N2 of the first and second polishing machines 23 and 33, which are the prerequisites, are constant or periodic fluctuations (the speeds appear to be constant when viewed on average), the equation (2) is used. ) Has a proportional relationship between the cumulative load tS and the cumulative work amount W because only the sampling time t and the rolling distance S of the sphere 2 are variables, and even if the cumulative load tS is used instead of the cumulative work amount W, it is almost the same. Because it is feasible.

That is, as shown in FIG. 12 corresponding to FIG. 2, the control device 19 does not have the rolling distance calculation unit 81 as compared with the control device 18, and is cumulative instead of the cumulative work calculation unit 82. It is configured to include a load calculation unit 92. In FIG. 12, the same components as those in FIG. 2 are numbered the same, and detailed description thereof will be omitted.

In the storage unit 86 of the control device 19, data relating the sphericity of the sphere 2 to the polishing amount of the sphere 2 and data relating the polishing amount of the sphere 2 to the cumulative load of the polishing process of the sphere 2 are stored. It is created under various processing conditions of polishing and stored as a database. These data show the same tendency as the data in the control device 18, and by constantly monitoring the cumulative load of the polishing process of the sphere 2, the sphere 2 can be polished to the target sphericity.

(6. Sphere polishing method using another type of control device)
Next, a method of polishing the sphere 2 by the control device 19 will be described with reference to FIG. The same steps as in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted. First, the sphere polishing device 1 prepares the sphere 2 so that it can be polished (step S1 in FIG. 13).

Next, the polishing control unit 83 starts polishing the sphere 2 (step S2 in FIG. 13, polishing control step). Then, the cumulative load calculation unit 92 calculates the cumulative load of the polishing process based on the measured load from the load sensor 16 (step S11 in FIG. 13, cumulative load calculation step).

The polishing control unit 83 determines whether or not the measured load measured by the load sensor 16 has reached the spark-out start load (step S5 in FIG. 13), and if the measured load has not reached the spark-out start load, the step Returning to S11, the above process is repeated. On the other hand, when the measured load reaches the spark-out start load, the motor control unit 84 is instructed to spark-out (step S6 in FIG. 13, polishing control step).

Then, the polishing control unit 83 determines whether or not the cumulative load of the polishing process obtained by the cumulative load calculation unit 92 is within a predetermined range (step S12 in FIG. 13, polishing control step), and the cumulative load of the polishing process. However, when it falls within the predetermined range, the polishing processing stop command is input to the motor control unit 84.

The motor control unit 84 stops the first motor 25 and the second motor 35 to stop the polishing process according to the input polishing process stop command, drives the motor 41, and moves the second moving body 14 to the upper retracted position. (Step S8 in FIG. 13, polishing control step), and all the processes are completed.

As described above, it was found that the cumulative load of the polishing process of the sphere 2 has a correlation with the processing accuracy of the sphere 2, that is, the sphericity. Therefore, by constantly monitoring the cumulative load of the polishing process of the sphere 2. , The sphere 2 can be polished to the target sphericity.

(7. Others)
In the above-described embodiment, the first polishing machine 23 and the second polishing machine 33 are configured to have the first polishing groove 23a and the second polishing groove 33a on the facing surfaces, respectively, but the first polishing machine 23 and the second polishing machine are configured. The first polishing groove 23a or the second polishing groove 33a may be formed on one of the facing surfaces of the board 33, and the other of the facing surfaces may have a flat structure in which no polishing groove is formed.

Further, the first polishing machine 23 and the second polishing machine 33 may have a flat structure in which no polishing groove is formed on the facing surface. In this case, in order to rotate the sphere 2 sandwiched between the first polishing machine 23 and the second polishing machine 33 around the central axis L1 (L2), the sphere polishing device 1 includes a cage 17 described below. It shall be configured.

The configuration of the cage 17 will be described with reference to the drawings. As shown in FIGS. 14 and 15, the cage 17 is formed in an annular shape and includes a main body portion 17a and a brim portion 17b. The main body 17a is formed in an annular shape and in a disk shape.

The inner diameter of the main body portion 17a is smaller than the inner diameter of the first polishing groove 23a, and the outer diameter of the main body portion 17a is larger than the outer diameter of the first polishing groove 23a. Further, the thickness (axis direction width) of the main body portion 17a is smaller than the outer diameter of the sphere 2. The main body 17a is placed on the surface of the first polishing machine 23 on the side facing the second polishing machine 33, that is, on the upper surface of the first polishing machine 23.

The main body portion 17a includes a plurality of (12 in this embodiment) circular pockets 17c at equal angular intervals in the circumferential direction. Each pocket 17c penetrates in the central axis L3 direction. Of the 12 pockets 17c, the four pockets 17c at 90 degree intervals do not surround the sphere 2 over the entire circumference on the surface of the main body 17a of the cage 17, and the openings 17d open in the radial direction. Is provided.

The opening 17d of the pocket 17c opens on the outer peripheral surface of the main body 17a of the cage 17. The opening 17d functions as a coolant discharge port. Further, the circumferential length of the opening 17d of the pocket 17c is formed to be smaller than the diameter of the sphere 2. Therefore, when the sphere 2 is arranged in the pocket 17c, the sphere 2 is restricted from coming out of the opening 17d of the pocket 17c. That is, the main body 17a of the cage 17 regulates the radial movement and the circumferential movement of the sphere 2.

The brim portion 17b extends from the inner peripheral edge of the main body portion 17a in the direction of the central axis L3, and restricts radial movement with respect to the first polishing machine 23. That is, the brim portion 17b is formed on the side opposite to the opening portion 17d of the pocket 17c. A plurality of brim portions 17b are formed intermittently in the circumferential direction, but may be formed over the entire circumference in the circumferential direction. The outer diameter of the brim portion 17b is formed to be approximately the same as the inner diameter of the first polishing machine 23.

Such a cage 17 is arranged in the spherical polishing device 1 as follows. The operator arranges the cage 17 in the facing region of the first polishing machine 23 and the second polishing machine 33. Specifically, the cage 17 is placed on the upper surface of the first polishing plate 23 so that the central axis L3 of the cage 17 and the central axis L1 of the first polishing plate 23 coincide with each other.

That is, the brim portion 17b of the cage 17 is in a state of entering the inner peripheral side of the first polishing machine 23, and the main body portion 17a of the cage 17 is in a state of being in contact with the upper surface of the first polishing machine 23. To do so. Then, the plurality of spheres 2 are arranged in the respective pockets 17c of the cage 17.

The cage 17 is indispensable when polishing is performed by the flat first polishing machine 23 and the second polishing machine 33 in which the polishing groove is not formed on the facing surface, but either one of the facing surfaces or the cage 17 is required. It can also be used when polishing is performed by the first polishing machine 23 and the second polishing machine 33 in which polishing grooves are formed on both sides.

Further, in the above-described embodiment, the first polishing machine 23 and the second polishing machine 33 are configured to have one annular first polishing groove 23a and a second polishing groove 33a on the facing surfaces, respectively. A plurality of concentric polishing grooves may be formed on either one or both of the facing surfaces of the plate 23 and the second polishing plate 33. Further, one spiral polishing groove may be formed on either one or both of the facing surfaces of the first polishing machine 23 and the second polishing machine 33.

When a polishing machine having a plurality of concentric polishing grooves or a polishing machine having a spiral polishing groove is used, the cumulative work amount calculation unit 82 or the cumulative load calculation unit 92 grinds the detected load G from the load sensor 16. The cumulative work or cumulative load is calculated by dividing by the number of spheres 2 inside.

Further, in the above-described embodiment, the first polishing machine 23 and the second polishing machine 33 are formed in an annular shape, but are formed in a rectangular parallelepiped shape and have a linear polishing groove formed on the facing surface. May be good.

Further, in the above-described embodiment, the rolling distance calculation unit 81 calculates the rolling distance of the sphere 2 based on the detection rotation speed from the encoders provided in the first and second motors 25 and 35. The rolling distance of the sphere 2 may be calculated by recognizing the image of the rolling sphere 2.

1: Sphere polishing device, 2: Sphere, 16: Load sensor, 17: Cage, 18, 19: Control device, 81: Rolling distance calculation unit, 82: Cumulative workload calculation unit, 83: Polishing control unit, 84: Motor control unit, 85: Fluid pressure adjustment unit, 86: Storage unit, 92: Cumulative load calculation unit

Claims (7)

The spheres are arranged to face each other so that the spheres can be pressed between the facing surfaces, and in order to polish the spheres, they can move relative to each other in a plane parallel to the facing surfaces and move in a direction perpendicular to the facing surfaces. A pair of possible polishing machines and
A moving device that relatively moves the pair of polishing machines in a plane parallel to the facing surface and relatively moves in a direction perpendicular to the facing surface.
A load sensor that measures the load generated on the sphere that is sandwiched between the facing surfaces due to the relative movement of the pair of polishing machines by the moving device.
Cumulative work amount calculation that calculates the work amount obtained from the load measured by the load sensor and the rolling distance of the sphere over time during the polishing process of the sphere, and obtains the cumulative work amount that correlates with the processing accuracy of the sphere. Department and
A polishing control unit that controls the moving device to perform polishing of the sphere based on the cumulative work amount by the cumulative work amount calculation unit.
A sphere polishing device. The sphere polishing device includes a storage unit that stores a database that associates the cumulative work amount with the processing parameters of the sphere and a database that associates the processing parameters of the sphere with the processing accuracy of the sphere.
The sphere polishing device according to claim 1, wherein the polishing control unit controls the moving device based on the cumulative work amount and the database to perform polishing processing of the sphere. The sphere polishing apparatus is provided with a rolling distance calculation unit for calculating a rolling distance of the sphere based on a relative moving speed in a plane parallel to the facing surface of the pair of polishing machines, according to claim 1 or 2. The described spherical polishing device. The spheres are arranged to face each other so that the spheres can be pressed between the facing surfaces, and in order to polish the spheres, they can move relative to each other in a plane parallel to the facing surfaces and move in a direction perpendicular to the facing surfaces. A pair of possible polishing machines and
A moving device that relatively moves the pair of polishing machines in a plane parallel to the facing surface and relatively moves in a direction perpendicular to the facing surface.
A load sensor that measures the load generated on the sphere that is sandwiched between the facing surfaces due to the relative movement of the pair of polishing machines by the moving device.
A cumulative load calculation unit that measures the load measured by the load sensor during polishing of the sphere over time and calculates the cumulative load that correlates with the machining accuracy of the sphere.
A storage unit that stores a database that associates the cumulative load with the processing parameters of the sphere and a database that associates the processing parameters of the sphere with the processing accuracy of the sphere.
A polishing control unit that controls the moving device to perform polishing of the sphere based on the cumulative load by the cumulative load calculation unit and the database stored in the storage unit .
A sphere polishing device. The pair of polishing machines are arranged so that the central axes are coaxial, and are provided so as to be relatively rotatable around the central axis and relatively movable in the direction of the central axis, and the facing surfaces of the pair of polishing machines are provided. The spherical polishing apparatus according to any one of claims 1 to 4 , further comprising a polishing groove formed in an annular shape around the central axis on at least one of the above. It is a sphere polishing method using a sphere polishing device.
The spherical polishing device is
The spheres are arranged to face each other so that the spheres can be pressed between the facing surfaces, and in order to polish the spheres, they can move relative to each other in a plane parallel to the facing surfaces and move in a direction perpendicular to the facing surfaces. A pair of possible polishing machines and
A moving device that relatively moves the pair of polishing machines in a plane parallel to the facing surface and relatively moves in a direction perpendicular to the facing surface.
A load sensor for measuring a load generated on the sphere sandwiched between the facing surfaces by the relative movement of the pair of polishing machines by the moving device is provided.
The sphere polishing method is
A rolling distance calculation step of calculating the rolling distance of the sphere based on the relative moving speed in a plane parallel to the facing surface of the pair of polishing machines.
Cumulative work amount calculation that calculates the work amount obtained from the load measured by the load sensor and the rolling distance of the sphere over time during the polishing process of the sphere, and obtains the cumulative work amount that correlates with the processing accuracy of the sphere. Process and
A polishing control step of controlling the moving device to polish the sphere based on the cumulative work amount obtained in the cumulative work amount calculation step, and a polishing control step.
A sphere polishing method. It is a sphere polishing method using a sphere polishing device.
The spherical polishing device is
The spheres are arranged to face each other so that the spheres can be pressed between the facing surfaces, and in order to polish the spheres, they can move relative to each other in a plane parallel to the facing surfaces and move in a direction perpendicular to the facing surfaces. A pair of possible polishing machines and
A moving device that relatively moves the pair of polishing machines in a plane parallel to the facing surface and relatively moves in a direction perpendicular to the facing surface.
A load sensor for measuring a load generated on the sphere sandwiched between the facing surfaces by the relative movement of the pair of polishing machines by the moving device is provided.
The sphere polishing method is
A cumulative load calculation step of measuring the load measured by the load sensor during polishing of the sphere over time and calculating a cumulative load that correlates with the machining accuracy of the sphere.
A polishing control step of controlling the moving device to polish the sphere based on the cumulative load obtained in the cumulative load calculation step, and a polishing control step.
Equipped with
The sphere polishing device includes a storage unit that stores a database that associates the cumulative load with the processing parameters of the sphere and a database that associates the processing parameters of the sphere with the processing accuracy of the sphere.
The polishing control step is a sphere polishing method in which the moving device is controlled based on the cumulative load and the database to polish the sphere.

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