JP2001150309A - Grinding method and grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly grinding-processing a whole surface of a disc at a high grinding accuracy. SOLUTION: A rotation shaft provided with a grinding tool 15 and a rotation shaft provided with a grinding tool 16 are rotated making a rotation center OG as a center. A disc W having a through hole H is supported and rotated by guide rollers 17, 18 contacted with an inner periphery Sa of the through hole H. A rotation center OW is deviated from the rotation center OG of the grinding tools 15, 16 by an eccentric amount E. The respective grinding tools 15, 16 have ring-like grinding surface 19 having a smaller outer diameter than that of the disc W and a larger inner diameter than that of the through hole H. The grinding surface 19 contacts the disc W so as to lay the through hole H and a slide movement direction of the grinding surface 19 becomes a direction approximated to a surface movement direction of the disc W accompanying with rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing technique for polishing both sides of a work while using a magnetic disk having a through hole formed in a central portion thereof as a work and converting the rotation of the work into the rotation of the work by a polishing tool.

[0002]

2. Description of the Related Art A magnetic disk used as a storage medium for a computer is formed by forming a magnetic disk substrate having a through hole in the center, that is, a substrate, using an aluminum alloy or glass, and then forming a magnetic film on both surfaces. It is manufactured by doing. When manufacturing a magnetic disk substrate, the magnetic disk substrate is polished with a polishing tool such as a grindstone or a buff in order to flatten the surface.

As a polishing apparatus for polishing both surfaces of a disk-shaped disk having a through hole in the center as described above, there is, for example, one disclosed in JP-A-54-81591. .

[0004]

As in the above-mentioned conventional polishing apparatus, the disk is sandwiched between two plane tools so that the rotation center of the disk is deviated from the rotation center of the plane tool, and the plane tool is rotated. The grinding surface of the flat tool can be slid on the surface of the disk while converting the rotating motion of the flat tool into the rotating motion of the disk. Has also been found to decrease.

In the conventional polishing apparatus, the polishing surface of the flat tool greatly protrudes to the outside of the disk, and the direction of sliding movement of the polishing surface with respect to the disk is large with respect to the direction of movement of the disk surface. As a result, the polished surface of the flat tool crosses the edge of the outer and inner peripheral surfaces of the disk at a large angle, especially at the part close to the outer peripheral surface of the disk, that is, at the radially outer and inner peripheral surfaces. It is considered that the polishing accuracy is lower at the near portion, that is, at the center portion in the radial direction, as compared with other portions.

The portion of the disk near the inner peripheral surface of the center hole is covered by the hub of the drive shaft when the disk is used, whereas the portion near the outer peripheral surface is used as a storage medium area. Therefore, it is particularly necessary to increase the polishing accuracy.

An object of the present invention is to enable uniform polishing of the entire surface of a disk with high polishing accuracy.

[0008]

SUMMARY OF THE INVENTION A polishing method according to the present invention is a polishing method for polishing both surfaces of a disk having a through hole formed in the center thereof, wherein the outer diameter is smaller than the outer diameter of the disk. A polishing tool having a ring-shaped polishing surface having an inner diameter larger than the inner diameter of the through hole is provided, and the first and second rotating shafts rotating concentrically are driven to rotate, and the rotation center of the work is rotated by the rotation. The workpiece is rotatably supported by a positioning member so that the polishing surface of each of the polishing tools is eccentric with respect to the rotation center of the shaft, and the polishing surface of each of the polishing tools straddles the through hole in an eccentric direction. The method is characterized in that both sides of the disk are polished by the respective polishing surfaces while converting the movement into a rotational movement of the disk. In the present invention, the disc may be supported by the positioning member such that the outer diameter of each of the polishing surfaces does not protrude outward from the outer peripheral surface of the disc. Also, the outer diameter of each of the polishing surfaces does not protrude outward from the outer peripheral surface of the disk, and the inner diameter of the polishing surface does not protrude inward than the inner peripheral surface of the through-hole. The entire polished surface may contact the disk.

A polishing apparatus according to the present invention is a polishing apparatus for polishing both surfaces of a disk having a through hole formed in a center portion, wherein the outer diameter is smaller than the outer diameter of the disk, and the inner diameter of the through hole is smaller. A first rotating shaft provided with a first polishing tool having a ring-shaped polishing surface having a larger inner diameter than an outer diameter of the disk and an inner diameter smaller than an inner diameter of the through hole; A second rotating shaft having a large ring-shaped polishing surface, a second polishing tool provided for holding the disc with the first polishing tool, and a rotation center of the workpiece as a rotation center of the rotation shaft; And a positioning member for rotatably supporting the work so that the polishing surface of each of the polishing tools is in contact with the through hole in the eccentric direction. To the rotational movement of the disc And characterized in that the said respective polishing surface while conversion so as to polish both surfaces of the disk. In the polishing apparatus of the present invention, the disc may be supported by the positioning member such that the outer diameter of each of the polishing surfaces does not protrude outside the outer diameter of the disc. Also, the outer diameter of each of the polishing surfaces does not protrude outward from the outer peripheral surface of the disk, and the inner diameter of the polishing surface does not protrude inward than the inner peripheral surface of the through-hole. The entire polished surface may contact the disk. Further, the positioning member may be brought into contact with an inner peripheral surface of the through hole.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1A is a front view showing the appearance of a polishing apparatus according to an embodiment of the present invention, FIG. 1B is a right side view of FIG. 1A, and FIG. FIG. 3 is an enlarged perspective view showing a main part of the polishing apparatus shown in FIG. 1, and FIG. 3 is an enlarged sectional view of FIG. 2 in a processing state.

This polishing apparatus has an apparatus main body composed of a base 1, a column 2 and a head 3, and the head 3 is provided with a pressure shaft supporting member 4 and a pressure receiving shaft supporting member 5. . A detachable unit 6 is provided on the base unit 1. A cassette accommodating a predetermined number of work disks is held in the unit 6. A disk W is pulled out from the unit 6 one by one to a polishing position and loaded. After polishing, it is returned to its original position and unloaded. The disc W has a through hole H at the center.
And has a circular outer peripheral surface Sb concentric with the circular inner peripheral surface Sa.

As shown in FIG. 2, the pressure shaft supporting member 4 is provided with a pressure shaft 11, and the pressure receiving shaft supporting member 5 is provided with a pressure receiving shaft 12, which are substantially concentric with each other. Is oriented horizontally. A drive motor 7 composed of a servomotor is incorporated in the head unit 3 as a drive source.
The rotation of the drive motor 7 is transmitted to the pressure shaft 11 and the pressure receiving shaft 12 via the power transmission mechanism 8.
A disc-shaped holder 13 is attached to the tip of the pressure shaft 11, and the disc-shaped holder 1 is similarly attached to the tip of the pressure receiving shaft 12.
In order to simultaneously polish both surfaces of the disk W, polishing tools 15, 16 made of nonwoven fabric or the like and also called polishing pads or polishing buffs are mounted on the holders 13, 14, respectively. One of the pressing shaft 11 and the pressure receiving shaft 12 becomes a first rotating shaft, the other becomes a second rotating shaft, one of the two polishing tools 15 and 16 becomes a first polishing tool, and the other becomes a second polishing tool. It is a tool.

As shown in FIG. 2, the pressure shaft 11 and the pressure receiving shaft 12 are driven to rotate in the same direction by the drive motor 7, and the pressure shaft 11 is moved in the axial direction so as to approach and separate from the pressure receiving shaft 12. Reciprocating freely. When the disk W is moved up between the two polishing tools 15 and 16 in a state where the pressure shaft 11 is separated from the pressure receiving shaft 12 and then the pressure shaft 11 is moved closer, the disk W A part thereof is sandwiched and supported, that is, sandwiched between the two polishing tools 15 and 16.

As shown in FIG. 3, both polishing tools 15, 1
6, the rotation center OW of the disk W held between the pressure shaft 11 and the pressure receiving shaft 12 has the rotation center OW.
Relative to the eccentricity E. As described above, since the discs W are eccentric, when the polishing tools 15 and 16 are driven to rotate while the disk W is held between the polishing tools 15 and 16, the polishing tools 15, 1 are rotated.
The rotational movement of the disk 6 is converted into the rotational movement of the disk W, and the polishing surfaces of the polishing tools 15 and 16 slide with respect to the surface of the disk W.

Two guide rollers 17, 18 as positioning members are attached to the pressure receiving shaft support member 5 so that the rotation center OW of the disk W is at a predetermined position. As shown in FIG. 2, it is arranged in a hollow hole 12a formed in the pressure receiving shaft 12, and comes into contact with the inner peripheral surface Sa of the through hole H.
Therefore, the disc W is sandwiched by the polishing tools 15 and 16, and the disc W is guided by the guide rollers 17 and 18 and is driven to rotate in the direction shown by the arrow so that the rotation center OW does not shift.

As shown in FIG. 3, each polishing tool 1
The outer diameters of the polishing tools 5 and 16 are smaller than the outer diameter of the disk W and larger than the inner diameter of the through-hole H in an annular or ring shape. Polished surface 19. Polished surface 19
The outer diameter and the inner diameter of the disk are the rotation center OW of the disk W and the polishing tool 1.
When the rotation centers OG of the rotation surfaces 5 and 16 are displaced from each other by the amount of eccentricity E and rotate, the outer diameter of the polishing surface 19 does not protrude outward from the outer peripheral surface Sb of the disk W, and
The inner diameter of the polishing surface 19 is set so as not to protrude more inward than the inner peripheral surface Sa of the disk W, and is set to a dimension that straddles the through hole H in the eccentric direction.

Therefore, during the polishing process, the polishing surface 19 does not slide so as to intersect both the outer peripheral edge and the inner peripheral edge, and the direction in which the polishing surface 19 slides with respect to the disk W is the surface of the disk. Is an angle approximating the moving direction of. In particular, in FIG.
As shown by b, the direction of sliding movement of the polishing surface 19 is substantially equal to the direction of rotation of the disk W with respect to the portion near the outer peripheral surface and the portion near the inner peripheral surface of the disk W. As a result, the disc W is
It is possible to uniformly polish the entire surface of the inner peripheral portion and the outer peripheral portion with the same polishing accuracy as the other portions.

The polishing surface 19 of each of the polishing tools 15 and 16
Is formed so as to straddle and surround the through hole H in the eccentric direction, and the sliding movement direction of the polishing surface 19 with respect to the disk W becomes an angle similar to the moving direction of the surface of the disk W. Even if the outer diameter protrudes outward of the outer peripheral surface Sb of the disk W, or the inner diameter protrudes inward of the inner peripheral surface Sa, the polishing accuracy of a portion near the outer peripheral surface and a portion near the inner peripheral surface of the disk W is improved. Can be maintained with substantially the same accuracy as the other parts, and the entire outer peripheral surface of the disk W can be reliably processed.

When the polishing process is performed, a polishing liquid containing polishing abrasive grains is supplied to the disk W from a nozzle (not shown). Instead of the supply from the nozzle, or together with the supply from the nozzle, a flow path for supplying the polishing liquid is provided in the hollow hole 12a formed in the pressure receiving shaft 12 and the hollow hole formed in the pressure receiving shaft 11, and The polishing liquid may be supplied to the surface of the disk W.

The number of the guide rollers 17 and 18 is not limited to the two described above, and the number and the mounting position can be appropriately set. Further, the guide rollers 17 and 18 are inserted into the hollow holes 1.
3A, the guide rollers 17a and 17b are disposed on the outside and contact the outer peripheral surface Sb of the disk W without being brought into contact with the inner peripheral surface Sa, as shown by a two-dot chain line in FIG. You may do it. However, even if the inner peripheral surface Sa and the disk surface near the inner peripheral surface Sa are damaged due to the contact of the guide rollers 17 and 8 with the inner peripheral surface Sa, the drive shaft is inserted into the through hole H when the disk W is used. Are fitted, and a hub is attached to the disk surface near the inner peripheral surface, so that the influence of the scratch does not cause a problem as a product. Therefore, the guide rollers 17 and 18 are formed on the inner peripheral surface Sa.
It is more preferable to make contact.

FIGS. 4 and 5 are enlarged sectional views showing the head portion 3 and the pressure shaft support member 4. The pressure shaft 11 is rotatable on the pressure shaft support member 4 and is reciprocally movable in the axial direction. It is supported by. In order to drive the pressing shaft 11, a driving gear 21 is fixed to a rear end of the pressing shaft 11, and a driven pulley 23 and a driven pulley 23 are mounted on a supporting shaft 22 fixed to the pressing shaft supporting member 4. The fixed idle gear 24 is rotatably mounted. As shown in FIG. 6, a drive pulley 26 fixed to a drive shaft 25 driven by the drive motor 7,
A timing belt 27 is stretched between the driven pulley 23 and the power transmission mechanism 8.
The rotation of the drive motor 7 is transmitted to the pressurizing shaft 11 via the idle gear 24.

A linear motion guide member 28 is provided between the pressure shaft support member 4 and the pressure shaft 11, and FIG. 7 shows an enlarged view of the linear motion guide member 28. . As shown in FIG. 7, the linear guide member 28 has a cylindrical body 29 also called a cage or a retainer, and a large number of balls 30 are rotatably held in the cylindrical body 29. The diameter of the ball 30 is larger than the thickness of the cylindrical body 29, and the pressing shaft 11 rotates on the outer peripheral surface of the cylindrical member 29 and comes into contact with the ball 30 to rotate and reciprocate in the axial direction with respect to the linear guide member 28. It is freely supported.

Therefore, when rotating the pressurizing shaft 11 in a stationary state, the static friction force is applied to the pressurizing shaft 11 by the ball 30 of the linear motion guide member 28. In this case, the rolling frictional dynamic force is applied from the ball 30 to the pressing shaft 11, and the dynamic frictional force is much smaller than the static frictional force. When the pressing shaft 11 is moved away from the pressure receiving shaft 12 so as to approach the disk W, first, the pressing shaft 11
Is rotated, and the pressing shaft 11 is moved closer in the axial direction while a dynamic friction force, which is a friction force much smaller than the static friction force, is applied to the pressing shaft 11. As a result, the pressing force applied to the pressing shaft 11 is not affected by the frictional force, and the set pressing force is transmitted to the disk W with high accuracy.

A pin 32 is provided on a bracket 31 fixed to the head portion 3.
One end of a swing lever member 34 is attached via 3, and the swing lever member 34 is swingable about the pin 32. The other end of the swing lever member 34 comes into contact with a spherical projection 35 formed on the rear end surface of the pressure shaft 11. The first and second brackets 31
Are mounted, and the piston rod 3 of each of the pneumatic cylinders 36, 37 is mounted.
The reference numerals 8 and 39 contact the rollers 41 and 42 rotatably provided on the swing lever member 34, respectively. Each of the rollers 41 and 42 is provided on the swing lever member 34 via a ball bearing, and the rotational friction resistance is reduced. The pneumatic cylinders 36 and 37 and the swing lever member 34 apply a pressing force to the pressing shaft 11 and constitute a pressing force applying means for applying a predetermined pressing force to the disk W via the pressing shaft 11.

As shown in FIG. 5, the distance between the contact point where the first piston rod 38 contacts the roller 41 and the center point of the pin 32 is L _1, and the second piston rod 39 is connected to the roller 42. The distance between the contact point that makes contact and the center point of the pin 32 is L _2, and the distance between the contact point at which the other end of the swing lever member 34 contacts the pressing shaft 11 and the center point of the pin 32. When the the _{L 3, L 1: L 2} : L 3 is 1: 2: set to 4.

Therefore, when the other end of the swing lever member 34 is pressed against the pressing shaft 11 with the pressing force f, the swing lever member 3 is moved by the first pneumatic cylinder 36.
Pressing force F ₁ added relative to 4 is four times the f, the pressing force F ₂ exerted against the rocking lever member 34 by a second pneumatic cylinder 37 is twice the f. As described above, the pressing force of each of the pneumatic cylinders 36 and 37 is reduced via the swing lever member 34 and transmitted to the pressurizing shaft 11.

The pistons slidable in the respective pneumatic cylinders 36 and 37 are provided with a seal member for preventing air from leaking from the inner peripheral surface of the cylinder. Contacting the inner peripheral surface of
The piston receives frictional resistance from the inner peripheral surface of the cylinder. Therefore, each pneumatic cylinder 36,
Even if an air pressure of a predetermined pressure is supplied in accordance with the pressure receiving area of the piston in 37, an error in the pressing force due to the frictional resistance will occur, but the error will cause the swing lever member 34 to swing. Since the pressure is reduced and transmitted to the pressure shaft 11, the pressing force applied to the pressure shaft 11 can be adjusted with high accuracy. In other words, the frictional resistance at the piston of the first pneumatic cylinder 36 is reduced to one-fourth and transmitted to the pressurizing shaft 11 by the length ratio of L ₁ to L ₃ , and is transmitted to the piston of the second pneumatic cylinder 37. The frictional resistance is reduced by half and transmitted to the pressure shaft 11. Thereby, the frictional resistance of the pistons in the two pneumatic cylinders 36 and 37 for applying the pressing force to the pressing shaft 11 is reduced, and the pressing force can be controlled with high accuracy. Note that the ratio of L ₁ : L ₂ : L ₃ can be set to an arbitrary value as well as the case described above.

FIG. 8 is a view showing a pneumatic circuit for supplying pneumatic pressure to the pneumatic cylinders 36 and 37. The pneumatic cylinder 43 for driving the pressurizing shaft 11 in a direction away from the pressure receiving shaft 12 includes a pressurizing shaft support member. The piston rod 44 of the pneumatic cylinder 43 comes into contact with the drive gear 21 directly or indirectly via a lever or the like.

Tank 46 connected to pneumatic pump 45
Includes a pneumatic pipe 47 connected to the pneumatic cylinder 36.
And a pneumatic pipe 48 connected to the pneumatic cylinder 37
And a pneumatic pipe 49 connected to the pneumatic cylinder 43. In order to control the air pressure supplied to the pneumatic cylinders 36 and 37 to an arbitrary pressure, the pneumatic piping 4
Each of the pressure regulators 7 and 48 is provided with a pressure regulator 51 or 52 composed of an electropneumatic regulator or the like, and the pressing force supplied to each of the pneumatic cylinders 36 and 37 is adjusted by an electric signal from a control unit. In order to set the air pressure supplied to the pneumatic cylinder 43, a pressure adjusting valve 53 is provided in the pneumatic pipe 49, and when the pressurizing shaft 11 is moved away from the pressure receiving shaft 12, the pneumatic cylinder 43 Will operate. The pneumatic pipes 47 to 49 are provided with switching valves 54 to 56, which are electromagnetic valves for opening and closing the respective flow paths, and are opened and closed by an electric signal.

In order to detect the pressing force f applied to the pressing shaft 11 by the swing lever member 34, the swing lever member 3
4 is provided with a load sensor 57, and based on a signal detected by this, the pressure regulators 51 and 52 are operated by a control signal from the control unit, and a predetermined pressing force is applied to the pressing shaft 11.

The pressing force F ₁ applied to the lever member 34 by the piston rod 38 from the first pneumatic cylinder 36 is set to a constant reference pressing force, and is actually applied to the pressing shaft 11 detected by the load sensor 57. The air pressure applied to the second pneumatic cylinder 37 according to the deviation between the pressing force f and the set pressing force is adjusted by the pressure regulator 52.
The pressing force of the deviation is controlled by the second
Alternatively, the pressing force may be controlled by the first pneumatic cylinder 36 and a constant reference pressing force may be applied by the second pneumatic cylinder 37. Thus, the reference pressing force may be applied by one pneumatic cylinder, and the pressing force may be adjusted by the other pneumatic cylinder.

Assuming that the rotation center of the pressure shaft 11 is substantially concentric or parallel to the rotation center of the pressure receiving shaft 12, polishing is performed on both surfaces of the disk W with the same pressing force being applied. Will be done.
When the pressing shaft 11 is inclined and the disc W is sandwiched between the two polishing tools 15 and 16, the distribution of the pressing force of the polishing tool against the disc W changes, and the disc W
The amount of polishing, that is, the degree of polishing, can be changed in accordance with the position in the radial direction.

For this purpose, a surface pressure adjusting member 61 is provided between the head portion 3 and the pressing shaft support member 4. The surface pressure adjusting member 61 is formed of a spring material, and includes a fixed piece 62 that extends and is fixed to the head portion 3 in the axial direction, and a movable piece 63 that extends and is fixed to the pressing shaft support member 4 in the axial direction.
And one end in the axial direction of the fixed piece 62 and the other end in the axial direction of the movable piece 63 are integrated by the connecting piece 64, and have a zigzag shape as a whole. Screw shafts 65 and 66 having male screw portions screwed to both ends of the movable piece 63 are rotatably attached to the head portion 3, respectively, and further provided with a male screw portion screwed to the head portion 3. A screw member 67 for pressing the movable piece 63 is rotatably attached to the head portion 3.

Therefore, each of the screw shafts 65-67
Is rotated by the surface pressure adjusting motor, whereby the rotation center O of the pressing shaft 11 is tilted up and down as shown by the arrow in FIG. In the illustrated case, the surface pressure adjusting member 61 is deformed by using a screw member. Alternatively, the surface pressure adjusting member 61 is formed by using a piezo element that deforms according to a voltage.
By deforming, the pressure shaft 11 may be inclined.

FIG. 9 is a block diagram showing a control circuit for controlling the operation of the polishing apparatus. A control unit 71 having a CPU (arithmetic processing unit) and the like are provided with an input key for instructing activation of the apparatus, and pressing. An operation panel 72 provided with keys and the like for inputting force and surface pressure, and a signal from the load sensor 57 are input. A drive motor 7 for rotatingly driving the pressurizing shaft 11 together with the pressure receiving shaft 12, respective pressure regulators 51 and 52 and respective switching valves 5
An operation signal is sent from the control unit 71 to 4, 55 and 56.

The control unit 71 includes an amplifier for amplifying an analog signal from the load sensor 57 and the like, an A / D converter for converting the signal to a digital signal, and a digital signal output to the pressure regulator 56 for converting into an analog signal. A D / A converter and the like are provided. The control unit 71 has a ROM 7
3, a RAM 74 is connected, and an arithmetic expression and map data of a correspondence relationship with a voltage value output to the pressure regulators 51 and 52 in accordance with a signal from the load sensor 57 are stored in the ROM 73. The distribution of the pressing force and the surface pressure applied to the shaft 11 is displayed on the display unit 75.

Further, as shown in FIG. 9, the controller 71 controls the surface pressure adjusting member 61 shown in FIGS. 4 and 5 to operate via the respective screw shafts 65-67. A control signal is sent to 76.

The procedure for polishing the surface of the disk W using such a polishing apparatus will be described with reference to FIG.

As shown in FIG. 10 (A), in a state where the pressing shaft 11 is retracted and a large gap is formed between the two polishing tools 15 and 16, the attachment / detachment unit 6 removes the jig 6a. As a result, the disk W is lifted and transported. Next, the guide rods 17 and 18 are moved forward so that the respective tips enter the through holes H. FIG. 10B shows a state where the guide rods 17 and 18 have entered.

In this state, when the pressure shaft 11 and the pressure receiving shaft 12 are first driven to rotate in the same direction by the drive motor 7, the pressure shaft 11 is brought into contact with the ball 30 of the linear motion guide member 28 by rolling contact. The pressing shaft 11 is in a state where dynamic frictional resistance is applied. In this manner, the switching valves 54 and 55 are energized under the condition that the dynamic friction, which is much smaller than the static friction, is generated between the pressurizing shaft 11 and the linear guide 28. Activate both pneumatic cylinders 36,37.

Thus, the pressurizing shaft 11 is pushed by the pneumatic cylinders 36 and 37 via the lever member 34 and moves forward toward the disk W. As shown in FIG. The two polishing tools 15 and 16 sandwich and are supported. After the disk W is held between the two polishing tools 15 and 16 in this manner, the jig 6a is retracted downward from the disk W in the figure as shown in FIG. The rotational movement of the two polishing tools 15 and 16
While being converted into the rotational motion of the disk W, the surfaces of the polishing tools 15 and 16 are brought into sliding contact with both surfaces of the disk W to perform polishing.

The pressure supplied to each of the pneumatic cylinders 36, 37 is controlled by pressure regulators 51, 52,
The pressing forces F ₁ and F ₂ applied to the swing lever member 34 by the respective pneumatic cylinders 36 and 37 are the
The frictional resistance of the pistons moving in the respective pneumatic cylinders 36 and 37 is reduced via the swing lever member 34 and transmitted to the pressurizing shaft 11. As a result, the pressing force of the pressing shaft 11 can be controlled with high accuracy.

The pressing force applied to the disk W by the pressure shaft 11 can be set in advance by operating a key or the like provided on the operation panel 72, and the load sensor 57 is pressed by the swing lever member 34. The pressing force applied to the shaft 11 is detected, and if there is a deviation,
A signal corresponding to the deviation is sent to the pressure regulators 51 and 52, and the set pressing force is maintained.

When the surface pressure applied by the two polishing tools 15 and 16 to the disk W is made different in the radial direction of the disk W, the operator inputs the surface pressure distribution using the operation panel 72. Accordingly, the pressing shaft 11 is tilted by the surface pressure adjusting member 61 based on the input distribution command, and the disc W is sandwiched by the polishing tools 15 and 16 at a predetermined surface pressure.

When the polishing of the disk is completed, the jig 6a rises from the detachable unit 6, and the disk W is held by the jig 6a. Then
When the energization of the switching valves 54 and 55 is stopped and the energization of the switching valve 56 is performed, the pressurizing shaft 11 is moved backward by the pneumatic cylinder 43. By moving the jig 6a downward in this state, the processed disk W is returned to the detachable unit 6. Further, an unprocessed disk W is newly loaded, and polishing is performed in the same manner as described above.

In the above-described embodiment, a case has been described in which a polishing pad made of a nonwoven fabric or the like is attached to the pressing shaft 11 and the pressure receiving shaft 12 as each polishing tool to perform polishing of the disk. The polishing apparatus shown in the figure can also be applied to the case where polishing or grinding is performed. Grinding and polishing are collectively referred to as polishing, and when performing grinding, a grindstone is attached to the pressing shaft and the pressure receiving shaft. Polishing includes lapping other than polishing to form a highly specular surface on the disk surface as described above, other than lapping performed to adjust the dimensional error of the disk or to improve the surface finish state. As in the case of polishing, alumina powder, silicon carbide powder, glass powder, diamond powder or the like is used as lapping abrasive grains, and lapping abrasive grains having a coarser grain size than polishing abrasive grains are used.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.

For example, in the embodiment, the disc W is lifted from below both the polishing tools 15 and 16 so as to be conveyed between the two polishing tools. You may make it do. In the illustrated embodiment, the pressing shaft 11 and the pressure receiving shaft 12 are respectively horizontal, but may be vertical. Further, although the pneumatic cylinders 35 and 45 are used, any fluid can be used as long as the cylinder is a fluid such as a hydraulic cylinder as a working medium.

[0050]

As described above, according to the present invention, the disk is pinched and polished by the two ring-shaped polishing tools so that the ring-shaped polishing surface straddles the center hole of the disk. During polishing, while converting the rotational movement of the polishing tool into the rotational movement of the disk, the direction of sliding of the polishing surface with respect to the disk is in a direction similar to the rotational direction of the disk, and the entire surface of the disk is polished with uniform accuracy. Can be processed. Thus, the entire surface of the disk can be polished with high precision while improving the polishing efficiency.

[Brief description of the drawings]

FIG. 1A is a front view showing an appearance of a polishing apparatus according to an embodiment of the present invention, and FIG. 1B is a right side view of FIG. 1A.

FIG. 2 is an enlarged perspective view showing a main part of the polishing apparatus shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view of FIG. 2 in a state where polishing is performed.

FIG. 4 is a cross-sectional view showing an enlarged view of the pressing shaft support shown in FIG. 1 in a state where the pressing shaft is separated from the pressure receiving shaft.

FIG. 5 is an enlarged cross-sectional view showing a pressing shaft supporting portion in a state where the pressing shaft approaches the pressure receiving shaft.

FIG. 6A is a cross-sectional view showing a part of the power transmission mechanism, and FIG. 6B is a cross-sectional view taken along the line VIB-VIB in FIG.

7A is a longitudinal sectional view showing the linear guide member shown in FIGS. 4 and 5, and FIG. 7B is a transverse sectional view of FIG.

FIG. 8 is a pneumatic circuit diagram showing pneumatic piping for operating a pneumatic cylinder.

FIG. 9 is a block diagram illustrating a control circuit of the polishing apparatus.

FIGS. 10A to 10D are process diagrams showing a polishing process.

[Explanation of symbols]

 Reference Signs List 7 drive motor 8 power transmission mechanism 11 pressure shaft 12 pressure receiving shaft 15, 16 polishing tool 19 polishing surface 21 drive gear 23 driven pulley 24 idle gear 26 drive pulley 28 linear guide member 29 cylindrical body E eccentric amount H through hole Sa inner peripheral surface Sb outer peripheral surface W disk

Claims (7)

[Claims] 1. A polishing method for polishing both surfaces of a disk having a through hole formed in a center portion, wherein the outer diameter of the disk is smaller than the outer diameter of the disk, and the inner diameter of the disk is smaller than the inner diameter of the through hole. A polishing tool having a large ring-shaped polishing surface is provided, the first and second rotating shafts rotating concentrically are driven to rotate, and the center of rotation of the work is eccentric with respect to the center of rotation of the rotating shaft. The work is rotatably supported by a positioning member so that the polishing surface of each of the polishing tools straddles the through hole in the eccentric direction, and while converting the rotational motion of the polishing tool into the rotational motion of the disk. A polishing method, wherein both sides of the disk are polished by the respective polishing surfaces. 2. The polishing method according to claim 1, wherein the positioning member supports the disk so that an outer diameter of each of the polishing surfaces does not protrude outward from an outer peripheral surface of the disk. A polishing method characterized by the above-mentioned. 3. The polishing method according to claim 1, wherein an outer diameter of each of the polishing surfaces does not protrude outward from an outer peripheral surface of the disk, and an inner diameter of the polishing surface is smaller than that of the through hole. A polishing method, wherein each polishing surface is entirely in contact with the disk without protruding inward from an inner peripheral surface. 4. A polishing apparatus for polishing both surfaces of a disk having a through hole formed in a central portion, wherein the outer diameter is smaller than the outer diameter of the disk and the inner diameter is larger than the inner diameter of the through hole. A first rotating shaft provided with a first polishing tool having a ring-shaped polishing surface; and a ring-shaped polishing having an outer diameter smaller than an outer diameter of the disk and an inner diameter larger than an inner diameter of the through hole. Surface
A second polishing tool for holding the disc by the first polishing tool;
A second rotating shaft provided with a polishing tool, and a center of rotation of the workpiece being eccentric with respect to a center of rotation of the rotating shaft, and a polishing surface of each polishing tool straddling the through hole in an eccentric direction. A positioning member for rotatably supporting the work so as to come into contact with the polishing tool, wherein the respective polishing surfaces grind both surfaces of the disk while converting the rotation of the polishing tool into the rotation of the disk. A polishing apparatus characterized in that: 5. A polishing apparatus according to claim 4, wherein said disc is supported by said positioning member such that an outer diameter of each of said polishing surfaces does not protrude outside an outer diameter of said disc. A polishing apparatus characterized in that: 6. The polishing apparatus according to claim 4, wherein an outer diameter of each of the polishing surfaces does not protrude outward from an outer peripheral surface of the disk, and an inner diameter of the polishing surface is smaller than that of the through hole. The polishing apparatus according to claim 1, wherein the entire polishing surface is in contact with the disk without protruding inward from an inner peripheral surface. 7. The polishing apparatus according to claim 4, wherein the positioning member is brought into contact with an inner peripheral surface of the through hole.