JP2016221586A - Spherical body polishing device and spherical body polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spherical body polishing device capable of improving the sphericity of a spherical body by keeping chip discharging performance well.SOLUTION: A spherical body polishing device (1) comprises: a first grinder (23) having a first polishing groove (23a) formed in an annular shape; a second grinder (33) relatively rotatably provided against the first grinder (23), and having a second polishing groove (33a) formed in an annular shape on a surface facing the first grinder (23); and a holder (17) formed in an annular shape, and arranged in an area where the first grinder (23) and the second grinder (33) face each other. The holder (17) comprises a plurality of pockets (17a1) which hold a plurality of spherical bodies (2) arranged between the first polishing grooves (23) and the second polishing groove (33), and open on an outer peripheral surface or an inner peripheral surface.SELECTED DRAWING: Figure 4

Description

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

  Patent Document 1 includes first and second polishing disks that have an outer peripheral polishing surface on a taper and rotate coaxially, and an inner peripheral polishing surface that is radially opposed to the outer peripheral surfaces of the first and second polishing disks. A spherical polishing apparatus is described that includes a third polishing disk having the same. This sphere polishing apparatus includes a cage in order to prevent contact between spheres adjacent in the circumferential direction (see FIGS. 3A and 3B of Patent Document 1).

  Patent Document 2 includes a first turntable, a second turntable that is a rotation center different from the first turntable, and a cage that is coaxially held by the first turntable and holds a plurality of spheres. A spherical polishing apparatus is described (see FIGS. 1 and 2 of Patent Document 2). The cage includes a pocket surrounding the sphere over the entire circumference.

Japanese Patent Laid-Open No. 1-271168 JP2013-248678A

  In the spherical polishing apparatus described in Patent Document 1, the first and second polishing discs are positioned on the inner peripheral side and the third polishing disc is positioned on the outer peripheral side with respect to the annular path along which the sphere moves. Therefore, the chip dischargeability is not good. On the other hand, in the sphere polishing apparatus described in Patent Document 2, since the sphere is sandwiched between the first rotating disk and the second rotating disk facing each other, the chips can be discharged in the radial direction of the rotating disk. However, since the cage surrounds the entire circumference of the sphere, the chip dischargeability is still not good.

  If chips accumulate in the polishing area, the accumulated chips may affect the sphericity of the sphere. Therefore, it is desirable to improve the dischargeability of chips.

  It is an object of the present invention to provide a sphere polishing apparatus and a sphere polishing method capable of improving the sphericity of a sphere by improving chip dischargeability.

(1. Sphere polishing equipment)
The spherical polishing apparatus includes a first polishing machine having a first polishing groove formed in an annular shape around one central axis on one surface, and the first polishing around a central axis coaxial with the central axis of the first polishing machine. A second polishing disc provided rotatably relative to the disc and having a second polishing groove formed annularly around the central axis on a surface facing the one surface of the first polishing disc; A cage formed in an annular shape and disposed in a region facing the first polishing disc and the second polishing disc, and a plurality of cages arranged between the first polishing trench and the second polishing trench The cage includes a plurality of pockets that hold a sphere and open to an outer peripheral surface or an inner peripheral surface.

(2. Sphere polishing method)
Further, the sphere polishing method is a sphere polishing method using the sphere polishing apparatus described above, wherein the plurality of spheres are arranged in the plurality of pockets between the first polishing groove and the second polishing groove. The plurality of spheres are polished by the first polishing groove and the second polishing groove by relatively rotating the first polishing disk and the second polishing disk.

(3. Effects of spherical polishing apparatus and method)
According to the sphere polishing apparatus and the sphere polishing method described above, the sphere is polished by the first polishing groove of the first polishing disk and the second polishing groove of the second polishing disk. Then, the sphere is held by an annular cage in a region where the first polishing disc and the second polishing disc are opposed to each other. Therefore, it can avoid that spherical bodies contact. The cage also includes a pocket that opens to the outer peripheral surface or the inner peripheral surface. Therefore, the chips generated by polishing are discharged from the opening of the pocket of the cage, and then discharged radially outward or radially inward of the first polishing disk and the second polishing disk. Therefore, the chip discharging property is improved, and as a result, the sphericity of the sphere is improved.

It is a figure which shows the structure of the spherical-polishing apparatus of this embodiment. FIG. 2 is an enlarged axial direction cross-sectional view of a cage constituting the sphere polishing apparatus of FIG. 1. It is II-II sectional drawing of FIG. It is the figure seen from the III direction of the holder | retainer of FIG. It is an enlarged view of the part containing a 1st grinding | polishing board, a 2nd grinding | polishing board, a holder | retainer, and a spherical body. It is a block block diagram of a control apparatus. It is a figure which shows the rotational speed of a 1st polishing disk and a 2nd polishing disk. The embodiment in which the rotation speeds of the first polishing disk and the second polishing disk are as shown in FIG. 6 and the comparative example in which the first polishing disk is fixed and the second polishing disk is rotated at a constant rotation, Degree ratio is shown. It is a figure which shows a part of spherical polishing apparatus in other embodiment, Comprising: It is an enlarged view of the part containing a 1st grinding | polishing board, a 2nd grinding | polishing board, a holder | retainer, and an imaging device.

(1. Configuration of the spherical polishing apparatus 1)
A spherical polishing apparatus 1 of the present embodiment will be described with reference to FIG. The spherical polishing apparatus 1 includes a base 11, a column 12, a first moving body 13, a second moving body 14, a vertical drive mechanism 15, a retainer 17, a fluid supply system 18, and a control device 16 (shown in FIG. 2). . The base 11 is installed on the floor, and includes a through hole 11a in the vertical direction at the center. The column 12 is fixed to the upper surface of the base 11. On the side surface of the column 12, guide rails 12a and 12b extending in the vertical direction are provided.

  The first moving body 13 is disposed on the upper surface of the base 11 and the through hole 11a. The first moving body 13 includes a first main body 21, a first polishing disk support 22, a first polishing disk 23, a first hydrostatic bearing 24, and a first motor 25.

  The first main body 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 21 a is positioned coaxially with the through hole 11 a of the base 11. The central axis of the central hole 21a is L1 and coincides with the vertical axis direction.

  The first polishing disk support 22 is provided to be rotatable about the central axis L <b> 1 with respect to the first main body 21. The first polishing disc support 22 includes a shaft portion 22 a that passes through the central hole 21 a of the first main body portion 21, and disc-shaped flange portions 22 b and 22 c that face the upper and lower surfaces of the first main body portion 21.

  The first polishing plate 23 is integrally fixed to the upper surface of the upper flange portion 22 b of the first polishing plate support 22. That is, the first polishing board 23 is provided to be rotatable around the central axis L <b> 1 with respect to the first main body portion 21. The first polishing board 23 is formed in an annular shape. Furthermore, the first polishing disk 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 a circular arc concave shape. The first polishing groove 23a polishes the sphere 2 to be polished.

  The first hydrostatic bearing 24 is held by the first main body 21, and the first polishing disk support 22 fixed integrally with the first polishing disk 23 is arranged in the radial direction and the thrust with respect to the first main body 21. Support in the direction. Specifically, the first hydrostatic bearing 24 includes a radial bearing 24a that is held in the central hole 21a of the first main body portion 21 and supports the outer peripheral surface of the shaft portion 22a by fluid pressure. Further, the first hydrostatic bearing 24 includes thrust bearings 24b and 24c that are held on the upper surface and the lower surface of the first main body 21 and are supported by fluid pressure on the flange portions 22b and 22c.

  In the present embodiment, the fluid supplied to the first hydrostatic bearing 24 is supplied from a common fluid supply source and branched to the radial bearing 24a and the thrust bearings 24b and 24c. The first hydrostatic bearing 24 further includes an orifice restrictor 24d (shown in FIG. 2). The orifice restrictor 24d is provided in each of the radial bearing 24a and the thrust bearings 24b and 24c. Here, since the position of the orifice restrictor 24d constituting the first hydrostatic bearing 24 is variable, the fluid pressure is variable. The first motor 25 is supported by the first main body 21 or the base 11 and rotationally drives the first polishing disc support 22.

  The second moving body 14 is disposed 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 disc support 32, a second polishing disc 33, a second hydrostatic bearing 34, and a second motor 35.

  The 2nd main-body part 31 is formed in a cylindrical shape, and has a center hole 31a, 31b in a lower disk part and an upper disk part. The central axes of the central holes 31a and 31b of the second main body 31 are L2 and coincide with the central axis L1 of the central hole 21a of the first main body 21. The cylindrical portion of the second main body 31 is slidably provided on the guide rails 12 a and 12 b on the side surface of the column 12. That is, the second main body 31 can move in the vertical direction with respect to the column 12.

  The second polishing disc support 32 is provided to be rotatable about the central axis L <b> 2 with respect to the second main body portion 31. The second polishing disc support 32 includes a shaft portion 32a penetrating the central hole 31a of the lower disc portion of the second main body portion 31, a disc-shaped flange portion facing the lower surface and the upper surface of the lower disc portion of the second main body portion 31. 32b and 32c are provided.

  The second polishing disk 33 is integrally fixed to the lower surface of the lower flange portion 32 b of the second polishing disk support 32. That is, the second polishing disc 33 is provided to be rotatable about the central axis L <b> 2 with respect to the second main body portion 31. The second polishing disc 33 is formed in an annular shape. Further, the second polishing disc 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 a circular arc concave shape. The second polishing groove 33a polishes the sphere 2 to be polished.

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

  The second hydrostatic bearing 34 holds the second polishing disc support 32 that is held by the lower disc portion of the second main body portion 31 and is integrally fixed to the second polishing disc 33 with respect to the second main body portion 31. Support in the radial and thrust directions. Specifically, the second hydrostatic bearing 34 includes a radial bearing 34a that is held in the center 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 hydrostatic bearing 34 includes thrust bearings 34b and 34c that are held on the upper and lower surfaces 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 and 32c.

  In the present embodiment, the fluid supplied to the second hydrostatic bearing 34 is supplied from a common fluid supply source and branched to the radial bearing 34a and the thrust bearings 34b and 34c. The second hydrostatic bearing 34 further includes an orifice restrictor 34d (shown in FIG. 2). The orifice restriction 34d is provided in each of the radial bearing 34a and the thrust bearings 34b and 34c. Here, since the position of the orifice restrictor 34d constituting the second hydrostatic bearing 34 is variable, the fluid pressure is variable. A fluid supply source that supplies fluid to the second hydrostatic bearing 34 is provided in common with a fluid supply source that supplies fluid to the first hydrostatic bearing 24. The second motor 35 is supported by the second main body 31 and rotationally drives the second polishing disc 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 includes 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 body portion 31 screwed into the ball screw 42. And a ball screw nut 43 fixed to the hole 31b.

  The retainer 17 is formed in an annular shape, and is disposed in a region where the first polishing disc 23 and the second polishing disc 33 are opposed to each other, and holds the plurality of spheres 2 to be polished. In the present embodiment, the cage 17 is placed on the first polishing board 23. Details of the cage 17 will be described later.

  The fluid supply system 18 supplies the fluid from the center of the second polishing disc 33 to the opposed region of the first polishing disc 23 and the second polishing disc 33, and distributes the fluid radially outward, thereby the first polishing disc. 23 and the fluid discharged from the outside in the radial direction of the second polishing disc 33 are collected. The fluid supply system 18 includes a fluid supply device 18a, supply channels 18b, 18c, and 18d, and a recovery channel 18e.

  The fluid supply device 18a is disposed on the side of the base 11, supplies the fluid, and filters and circulates the recovered fluid. Further, the fluid supply device 18a controls the temperature of the fluid to be supplied, and reduces the thermal effect on the sphere 2 to be polished.

  The supply flow path 18b is formed in the base 11, is connected to the discharge port of the fluid supply device 18a, and has a discharge port on the through hole 11a side. The supply flow path 18 c is formed in the first motor 25, communicates with the supply flow path 18 b formed in the base 11, and has a discharge port at the center of the first motor 25. The supply channel 18 d is formed at the center of the first polishing disc support 22, communicates with the discharge port of the supply channel 18 c formed in the first motor 25, and the discharge port at the center of the first polishing disc support 22. Have The recovery channel 18e is formed in the base 11, has a recovery port on the outer peripheral side of the first main body 21, and is connected to the fluid supply device 18a.

(2. Detailed configuration of cage 17)
The detailed structure of the holder | retainer 17 is demonstrated with reference to FIGS. The cage 17 is formed in an annular shape and holds (accommodates) the plurality of spheres 2 disposed between the first polishing groove 23a and the second polishing groove 33a. In the present embodiment, the cage 17 is placed on the first polishing board 23. The cage 17 includes a main body portion 17a and a collar portion 17b.

  The main body portion 17a is annular and formed 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. Furthermore, the thickness (axial width) of the main body portion 17 a is smaller than the outer diameter of the sphere 2. The main body portion 17 a is placed on the surface of the first polishing plate 23 that faces the second polishing plate 33. In the present embodiment, the main body portion 17 a is placed on the upper surface of the first polishing board 23.

  The main body portion 17a includes a plurality of pockets 17a1 in the circumferential direction. The plurality of pockets 17a1 penetrates in the axial direction. The plurality of pockets 17a1 do not surround the sphere 2 over the entire circumference on the surface of the main body portion 17a of the cage 17, and open in the radial direction. In the present embodiment, the plurality of pockets 17 a 1 are opened on the outer peripheral surface of the main body portion 17 a of the cage 17. However, you may make it the some pocket 17a1 open to the inner peripheral side of the main-body part 17a of the holder | retainer 17. FIG.

  In particular, in the present embodiment, in the fluid supply system 18, the discharge port of the supply flow path 18 d through which the fluid is discharged is formed at the center of the first polishing plate support 22, so that the fluid is the first polishing plate 23. Circulates radially outward from the center. In this case, the pocket 17a1 is preferably opened on the outer peripheral surface of the main body 17a of the cage 17. On the other hand, in the fluid supply system 18, when the fluid flows from the outer peripheral surface side of the first polishing board 23 toward the center, the pocket 17 a 1 is opened on the inner peripheral surface of the main body portion 17 a of the cage 17. Good. These reasons will be described later.

  The opening width of the pocket 17a1 (corresponding to the circumferential length of the opening of the pocket 17a1) is formed smaller than the diameter of the sphere 2. Therefore, in a state where the sphere 2 is disposed in the pocket 17a1, the sphere 2 is restricted from coming out of the opening of the pocket 17a1. That is, the main body portion 17a of the cage 17 regulates the radial movement and the circumferential movement of the sphere 2.

  The collar portion 17 b extends in the axial direction from the main body portion 17 a and regulates radial movement relative to the first polishing board 23. In the present embodiment, the collar portion 17b extends in the axial direction from the inner peripheral edge of the main body portion 17a. That is, the collar portion 17b is formed on the side opposite to the opening of the pocket 17a1. A plurality of collar 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 collar portion 17 b is formed to be approximately the same as the inner diameter of the first polishing board 23.

  Here, the cage 17 may be disposed so as to be rotatable relative to the first polishing board 23, or may be disposed so as not to be rotatable. When the cage 17 is rotatable relative to the first polishing disc 23, a slide bearing or a rolling bearing may be disposed at a contact portion between the cage 17 and the first polishing disc 23.

(3. Configuration of the control device 16)
As shown in FIG. 5, the control device 16 includes a motor control unit 51 and a fluid pressure adjustment unit 52. The motor control unit 51 controls the motors 25, 35 and 41. That is, when the motor controller 51 drives the first motor 25 to rotate, the first polishing board 23 rotates. Further, when the motor control unit 51 rotationally drives the second motor 35, the second polishing board 33 rotates. Further, when the motor control unit 51 rotationally drives the motor 41, the second moving body 14 moves up and down.

  The fluid pressure adjusting unit 52 adjusts the throttle amount of each of the orifice throttles 24d and 34d. When the fluid pressure adjusting unit 52 moves the position of the first orifice restrictor 24d, the rigidity of the first hydrostatic bearing 24 changes. Further, the fluid pressure adjusting unit 52 moves the position of the second orifice restrictor 34d, whereby the rigidity of the second hydrostatic bearing 34 changes.

  In the present embodiment, the first orifice restrictor 24d simultaneously adjusts all the fluid pressures of the radial bearing 24a and the thrust bearings 24b and 24c. That is, by adjusting the first orifice restrictor 24d, the rigidity by the radial bearing 24a and the rigidity by the thrust bearings 24b and 24c are adjusted. At the same time, the moment stiffness by the first hydrostatic bearing 24 is adjusted.

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

  In addition, by providing the first orifice restrictor 24d in each of the radial bearing 24a and the thrust bearings 24b and 24c, the fluid pressures of the radial bearing 24a and the thrust bearings 24b and 24c can be adjusted independently. The same applies to the second orifice stop 34d.

  In the above embodiment, the fluid pressures of the first and second hydrostatic bearings 24 and 34 are variable by changing the positions of the first and second orifice restrictors 24d and 34d. In addition, the fluid pressure adjusting unit 52 can also adjust the fluid pressure supplied by the fluid supply source to the first and second hydrostatic bearings 24 and 34.

(4. Method of polishing sphere 2 using sphere polishing apparatus 1)
A method of polishing the sphere 2 will be described with reference to FIGS. The fluid pressure adjusting unit 52 (shown in FIG. 5) of the control device 16 has an orifice so that the fluid pressure of the first and second hydrostatic bearings 24 and 34 becomes the fluid pressure used when the sphere 2 is polished. The diaphragms 24d and 34d are set in advance.

  Then, the motor control unit 51 of the control device 16 drives the motor 41 to move the second moving body 14 upward. In this state, as shown in FIG. 4, the operator places the retainer 17 on the upper surface of the first polishing board 23. That is, the collar portion 17b of the cage 17 enters the inner peripheral side of the first polishing disc 23, and the main body portion 17a of the cage 17 comes into contact with the upper surface of the first polishing disc 23. Like that.

  A plurality of spheres 2 that are polishing materials are disposed in the respective pockets 17 a 1 of the cage 17 and are disposed in the first polishing grooves 23 a of the first polishing board 23. Subsequently, the motor control unit 51 of the control device 16 drives the motor 41 to move the second moving body 14 downward, and as shown in FIG. 4, the second polishing groove 33 a of the second polishing plate 33. Is in contact with the sphere 2.

  Subsequently, the fluid supply device 18a supplies a fluid. That is, the fluid is discharged from the discharge port of the supply flow path 18d located at the center of the first polishing disk 23, flows through the opposed region of the first polishing disk 23 and the second polishing disk 33 radially outward, It is discharged radially outward of the first polishing disk and the second polishing disk 33. The discharged fluid is recovered from the recovery flow path 18e to the fluid supply device 18a.

  Subsequently, the control device 16 drives the first motor 25 so that the rotation speed N1 of the first polishing board 23 is a constant value as shown in FIG. 6, and sets the rotation speed N2 of the second polishing board 33. As shown in FIG. 6, the second motor 35 is driven so as to have a constant value. In FIG. 6, when the rotation speed is positive, the rotation is in one direction, and when the rotation speed is negative, the rotation is in the other direction. The rotation speed N1 of the first polishing board 23 and the rotation speed N2 of the second polishing board 33 have the relationship of the formula (1). That is, the rotation direction of the first polishing board 23 and the rotation direction of the second polishing board 33 are opposite to each other.

  Further, the rotation speed N1 of the first polishing board 23 and the rotation speed N2 of the second polishing board 33 are controlled to be constant values. In the present embodiment, the absolute value | N1 | of the rotation speed N1 of the first polishing board 23 and the absolute value | N2 | of the rotation speed N2 of the second polishing board 33 are the same as shown in Expression (2). It is.

  In this way, the sphere 2 is polished by the first and second polishing disks 23 and 33. When the time set in this state has elapsed, the motor control unit 51 of the control device 16 stops the first motor 25 and the second motor 35 and drives the motor 41 to move the second moving body 14 upward. Let

(5. Effects of the basic configuration of the spherical polishing apparatus 1)
As described above, the spherical polishing apparatus 1 is provided so as to be rotatable around the central axis L1, and has a first polishing disk 23 having a first polishing groove 23a formed in an annular shape around the central axis L1 on one surface. And rotatably provided around a central axis L2 coaxial with the central axis L1 of the first polishing disc 23, and annularly around the central axis L2 on a surface facing one surface of the first polishing disc 23 And a second polishing disc 33 having a second polishing groove 33a to be formed. Thus, by making the first and second polishing disks 23 and 33 facing each other rotatable, the plurality of spheres 2 are arranged in the first and second polishing grooves 23a and 33a, and the plurality of spheres 2 are polished. Will be processed at the same time.

  Furthermore, the freedom degree of grinding becomes high by making the 1st, 2nd polishing disk 23 and 33 rotatable. For example, the first and second polishing disks 23 and 33 can position the central axes L1 and L2 of the first and second polishing disks 23 and 33 with high accuracy by increasing the fluid pressure as will be described later. In particular, since the first and second polishing discs 23 and 33 are supported by hydrostatic bearings, it is possible to continue positioning with high accuracy by preventing initial wear and aged wear compared to the case of using a rolling bearing. it can. Further, the first and second polishing discs 23 and 33 can allow the deviation of the central axes L1 and L2 of the first and second polishing discs 23 and 33 by lowering the fluid pressure as will be described later. As a result, the sphere 2 can be polished with high accuracy.

(6. Effect by control operation by motor control unit 51)
An example in which the motor control unit 51 of the control device 16 controls the first polishing board 23 and the second polishing board 33 as shown in FIG. The sphericity of the sphere 2 was measured with respect to the comparative example when the was rotated. The sphericity ratio of the sphere 2 when a certain sphericity is set to 1 is shown in FIG. FIG. 7 shows a range of sphericity of the plurality of spheres 2 in the example and the comparative example. That is, the length in the vertical direction in FIG. 7 means variation in sphericity of the plurality of spheres 2.

  From FIG. 7, the minimum value of the sphericity of the sphere 2 in the example is similar to that of the comparative example, but the maximum value of the sphericity of the sphere 2 in the example is smaller than that of the comparative example. That is, the variation in the sphericity of the sphere 2 in the embodiment is smaller than that in the comparative example. As described above, the motor control unit 51 of the control device 16 sets the rotation direction of the first polishing plate 23 and the rotation direction of the second polishing plate 33 in opposite directions, so that the moving speed of the sphere 2 is changed to the first polishing plate. This is smaller than when the board 23 is fixed. That is, the centrifugal force acting on the sphere 2 is significantly reduced. As a result, it is considered that the sphericity of the sphere 2 is improved.

  Further, as shown in the embodiment, the control device 16 makes the absolute value | N1 | of the rotation speed N1 of the first polishing board 23 the same as the absolute value | N2 | of the rotation speed N2 of the second polishing board 33. The sphere 2 is polished. In this case, the sphere 2 rotates at the same position. That is, the sphere 2 only rotates without revolving. Therefore, the centrifugal force acting on the sphere 2 becomes zero. As a result, the sphericity of the sphere 2 is reliably improved.

(7. Effect of cage)
The spherical body 2 is held by an annular cage 17 in a region where the first polishing disc 23 and the second polishing disc 33 are opposed to each other. Therefore, it can avoid that the spherical bodies 2 contact. Moreover, the holder | retainer 17 is provided with the pocket 17a1 opened to an outer peripheral surface or an internal peripheral surface. Therefore, the chips generated by the polishing are discharged to the outside from the opening of the pocket 17a1 of the cage 17, and then discharged to the radially outer side or the radially inner side of the first polishing disk 23 and the second polishing disk 33. . Therefore, the dischargeability of the chips becomes good, and it is possible to prevent the chips from accumulating in a region where the first polishing disk 23 and the second polishing disk 33 are opposed to each other. As a result, the sphericity of the sphere 2 is improved.

  In addition, the opening width of the outer peripheral surface or inner peripheral surface of the plurality of pockets 17 a 1 is formed smaller than the diameter of the sphere 2. Therefore, in a state where the sphere 2 is disposed in the pocket 17a1, the sphere 2 is restricted from coming out of the opening of the pocket 17a1. That is, the main body portion 17a of the cage 17 regulates the radial movement and the circumferential movement of the sphere 2.

  The first polishing disk 23 is disposed below the second polishing disk 33, and the cage 17 includes a plurality of pockets 17 a 1 and the side of the first polishing disk 23 that faces the second polishing disk 33. And a collar portion 17b that extends in the axial direction from the main body portion 17a and is restricted from moving in the radial direction with respect to the first polishing disc 23.

  The flange portion 17 b restricts the cage 17 from moving in the radial direction with respect to the first polishing disc 23. Therefore, it can suppress that the holder | retainer 17 gives the force to the radial direction of the 1st grinding | polishing board 23 with respect to the spherical body 2. FIG. As a result, the sphericity of the sphere 2 is improved by suppressing the force on the sphere 2 that is unnecessary for polishing.

  The collar portion 17b is formed on the outer peripheral side or inner peripheral side of the cage 17 on the side opposite to the opening of the pocket 17a1. That is, the collar part 17b is provided in the position which does not interfere with discharge of chips. Therefore, the function by the collar part 17b can be exhibited, making chip discharge | emission property favorable.

(8. Action by fluid)
By the fluid supply system 18, the fluid flows from the inner peripheral side of the cage 17 outward in the radial direction. Therefore, circulating the fluid has a function of discharging to the outside from the facing region of the first polishing plate 23 and the second polishing plate 33 together with the chips.

  Here, the pocket 17 a 1 of the cage 17 opens on the outer peripheral surface of the cage 17. In other words, in the cage 17, the opening of the pocket 17 a 1 is located radially outward of the cage 17 from the position of the sphere 2 held by the cage 17. That is, the direction in which the opening of the pocket 17a1 is located with respect to the position of the sphere 2 coincides with the fluid flow direction. Therefore, it becomes easy for the fluid to flow in the direction from the inside of the pocket 17a1 to the opening of the pocket 17a1, and the chip discharging property is further improved.

(9. Other embodiments)
Another embodiment of the present invention will be described with reference to FIG. As shown in FIG. 8, the spherical body polishing apparatus 1 includes an imaging device 19 in addition to the above. The imaging device 19 is installed on the side of the base 11 and images the facing region from the radially outer side in the facing region between the first polishing board 23 and the second polishing board 33. Specifically, the imaging device 19 images the rotation state of the sphere 2 located in the facing area.

  Here, the first polishing disk 23 and the second polishing disk 33 rotate in opposite directions, and the absolute value | N1 | of the rotation speed N1 of the first polishing disk 23 and the absolute value of the rotation speed N2 of the second polishing disk 33. | N2 | is the same. Therefore, the sphere 2 does not move in the revolution direction but rotates at the same position. Therefore, the imaging device 19 can always capture an image of the operation of the same sphere 2.

  At this time, the imaging device 19 images the opposing area from the outside in the radial direction of the opposing area. However, the cage 17 is arranged in the facing region. The pocket 17 a 1 of the cage 17 opens on the outer peripheral surface of the cage 17. Therefore, the imaging device 19 can image the sphere 2 held inside the pocket 17a1 from the opening of the pocket 17a1. When the imaging device 19 images the operation of the sphere 2, it is possible to change the rotation speeds of the first polishing board 23 and the second polishing board 33.

DESCRIPTION OF SYMBOLS 1: Sphere polishing apparatus, 2: Sphere, 11: Base, 12: Column, 16: Control device, 17: Retainer, 17a: Body part, 17a1: Pocket, 17b: Brim part, 18: Fluid supply system, 19 : Imaging device, 23: first polishing disk, 23a: first polishing groove, 24: first static pressure bearing, 33: second polishing disk, 33a: second polishing groove, 34: second static pressure bearing

Claims (6)

A first polishing disc having a first polishing groove formed annularly around the central axis on one surface;
The first polishing machine is provided so as to be rotatable relative to the first polishing machine around a central axis that is coaxial with the central axis of the first polishing machine, and on the surface facing the one surface of the first polishing machine, A second polishing machine having a second polishing groove formed annularly around the central axis;
A plurality of spheres that are annularly formed and are disposed in a facing region between the first polishing disk and the second polishing disk, and are disposed between the first polishing groove and the second polishing groove. The retainer provided with a plurality of pockets that open to the outer peripheral surface or the inner peripheral surface;
A spherical polishing apparatus comprising:   The sphere polishing apparatus according to claim 1, wherein an opening width of an outer peripheral surface or an inner peripheral surface of the plurality of pockets is formed smaller than a diameter of the sphere. The first polishing disc is disposed opposite to the lower side of the second polishing disc,
The cage is
A main body portion that includes the plurality of pockets and is placed on a surface of the first polishing disk facing the second polishing disk;
A collar portion extending in the axial direction from the main body portion and restricted in radial movement relative to the first polishing disc;
The sphere polishing apparatus according to claim 1, comprising:   The spherical polishing apparatus according to claim 3, wherein the collar portion is formed on an outer circumferential side or an inner circumferential side of the cage on a side opposite to the opening of the pocket. The spherical polishing apparatus includes a fluid supply system that circulates a fluid radially outward from the center of the first polishing board,
The spherical polishing apparatus according to any one of claims 1 to 3, wherein the plurality of pockets open to an outer peripheral surface of the cage. A sphere polishing method using the sphere polishing apparatus according to claim 1,
The plurality of spheres are disposed in the plurality of pockets between the first polishing groove and the second polishing groove, and the first polishing disk and the second polishing disk are rotated relatively to each other. A sphere polishing method, wherein the plurality of spheres are polished by the first polishing groove and the second polishing groove.

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