JPH11277389A - Grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding machine capable of reducing sliding resistance acting on a housing and supporting a spindle, forwarding and moving a grinding wheel minutely, and finishing a work accurately in grinding. SOLUTION: A grinding wheel driving device 16 is disposed vertically in a stand up condition in response to a work holding device holding a work. The grinding wheel holding device 16 is provided with a housing 23 supported by a holding cylinder 23 located over a frame 13 in such a way as to be freely moved up and down by way of a static pressure radial bearing 24, a spindle 25 rotatably pivoted in the inside of the housing 23, a magnet 17 held by the end part of the spindle 25 in response to the work, and with a mechanism capable of converting rotating movement into linear movement, and a feeding mechanism 32 is provided, which moves the housing up and down vertically, and allows the grinding wheel to be in contact with/separated from the work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine for precisely grinding a workpiece such as a silicon wafer.

[0002]

2. Description of the Related Art In a conventional grinding machine of this type, a grindstone driving device is provided corresponding to a work holding device for holding a work. In this grindstone driving device, a cylindrical housing is movably fitted and supported on a holding cylinder on a frame. A spindle is rotatably supported in the housing, and a grindstone is held at an end of the spindle so as to correspond to the workpiece. Then, the housing is moved by the rotation of the motor, and the grindstone is fed and moved in a direction of coming and going with respect to the work.

[0003]

However, in this conventional grinding machine, a housing rotatably housing and supporting a spindle is directly fitted and supported on a holding cylinder on a frame. For this reason, when the housing is moved in the axial direction in the holding cylinder and the grindstone is fed and moved with respect to the work, a large sliding resistance acts on the housing. Therefore, there has been a problem that the grindstone cannot be finely fed and moved, and the work cannot be precisely ground.

The present invention has been made by paying attention to such problems existing in the conventional technology. The purpose is to reduce the sliding resistance acting on the housing that houses and supports the spindle, and to feed and move the grindstone minutely, and to grind the workpiece precisely. Is to provide.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a work holding device for holding a work, and a work holding device that stands up and down in a vertical direction corresponding to the work holding device. A housing supported on the holding cylinder on the frame via a static pressure bearing so as to be movable in the vertical direction, and a shaft rotatably mounted in the housing. Supported spindle,
A grindstone held at the end of the spindle corresponding to the work, a mechanism for converting a rotary motion into a linear motion is provided, and feed means for moving the housing up and down to move the grindstone toward and away from the work is provided. Things.

According to a second aspect of the present invention, in the grinding machine according to the first aspect, the feed means includes a motor, a ball screw, and a nut, and the ball screw is disposed on the same axis as the housing. is there.

According to a third aspect of the present invention, in the grinding machine according to the first or second aspect, the spindle is supported in the housing via a hydrostatic bearing. According to a fourth aspect of the present invention, in the grinding machine according to any one of the first to third aspects, the grinding machine is vertically erected on a side opposite to a grindstone driving device, corresponding to the work holding device. And a second grindstone driving device, which is supported by a holding cylinder on the frame via a static pressure bearing so as to be movable vertically.
A housing, a second spindle rotatably supported in the second housing, a second grindstone held at an end of the second spindle corresponding to the workpiece, and a mechanism for converting rotational motion into linear motion And a second feed means for moving the second housing up and down to move the second grindstone toward and away from the workpiece.

According to a fifth aspect of the present invention, in the grinding machine according to the fourth aspect, the second feed means includes a motor, a ball screw, and a nut portion, and the ball screw is disposed on the same axis as the second housing. It was established.

According to a sixth aspect of the present invention, in the grinding machine according to the fourth or fifth aspect, the second spindle is supported in the second housing via a hydrostatic bearing.

According to a seventh aspect of the present invention, in the grinding machine according to any one of the first to sixth aspects, the housing is prevented from rotating between the housing and the holding cylinder on the frame. To prevent rotation.

In the invention according to claim 8, in the grinding machine according to claim 7, the detent means includes a guide cylinder provided on one of the housing and the holding cylinder, and a housing and the holding cylinder. And a guide rod slidably fitted in the guide cylinder via a static pressure bearing.

According to a ninth aspect of the present invention, in the grinding machine according to the seventh or eighth aspect, the detent means supports the weight of the housing and its related members,
A balance mechanism for maintaining a balance when the housing is moved by the feeding means is provided.

According to the tenth aspect of the present invention, the seventh to seventh aspects are described.
The grinding machine according to claim 9,
The detent means is provided with a fine adjustment feed mechanism for allowing fine rotation of the housing and finely moving the housing vertically.

According to an eleventh aspect of the present invention, in the grinding machine according to the third aspect, the flange portion on the spindle is provided with a communication hole for communicating the vertical space of the hydrostatic bearing. .

[0015] According to the twelfth aspect of the present invention, in the fourth aspect,
The grinding machine according to any one of claims 6,
Between the second housing and the holding cylinder on the frame,
A second detent means for detenting the second housing is provided.

[0016] According to the invention of claim 13, in claim 12
In the grinding machine described in the above, the second detent means is provided on a guide cylinder provided on one of the second housing and the holding cylinder, and provided on the other of the second housing and the holding cylinder. And a guide rod slidably fitted through a static pressure bearing.

According to a fourteenth aspect of the present invention, in the grinding machine according to the sixth aspect, a communicating hole for communicating a vertical space of the hydrostatic bearing is formed in the flange portion on the second spindle. It is.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the frame 11 of the double-headed grinding machine according to the present embodiment includes a lower frame 12 and an upper frame 13 fixed on the lower frame 12. A work holding device 14 is mounted on the lower frame 12, and a thin plate-like work 1 such as a silicon wafer is mounted on the work holding device 14.
5 is detachably held and rotated by a rotation motor (not shown).

A first grindstone driving device 16 is mounted on the upper frame 13 in an upright state, and a first grindstone 17 is provided below the first grindstone driving device 16 with a work holding device 14.
It is provided so as to correspond to the upper surface of the upper work 15. A second grindstone driving device 18 is mounted on the lower frame 12 in a vertically upright state, and a second grindstone 19 is mounted on the upper portion of the second grindstone driving device 18 on the work holding device 14.
5 so as to correspond to the lower surface. Then, the grinding surfaces of the opposite end surfaces of both grinding wheels 17 and 19 are arranged in parallel,
Both of the front and back surfaces of the work 15 are simultaneously ground by these ground surfaces.

The structure of the first grinding wheel driving device 16 will be described in detail. As shown in FIG. 3, a holding cylinder 22 is fixedly penetrated to the upper wall of the upper frame 13, and a cylindrical first housing 23 is provided therein with a hydrostatic radial bearing 24.
Are inserted and supported movably in the up and down direction via the. In the center of the first housing 23, a first spindle 25 is rotatably supported via a hydrostatic radial bearing 26 and a hydrostatic thrust bearing 27.
There is provided a grindstone table 28 for holding the grinding wheel. A first rotation motor 29 is disposed in the first housing 23,
The first spindle 25 is driven by the first rotation motor 29.
, The first grindstone 17 is rotated.

A flange 30 is provided near the lower end of the first spindle 25, and a plurality of communication holes 31 for communicating the upper space 27a and the lower space 27b of the hydrostatic thrust bearing 27 to the flange 30. Are formed.
Thus, the upper and lower spaces 27a of the hydrostatic thrust bearing 27,
27b to prevent the pressure difference of the pressure air from occurring,
When the first spindle 25 is rotated by the first rotation motor 29, the first spindle 25 is prevented from being vibrated.

As shown in FIGS. 3 and 4, the holding cylinder 2
At the upper end of 2, a first feed mechanism 32 as a first feed means is provided. That is, a lid plate 33 is attached to the upper end of the holding cylinder 22 via the spacer 34, and through holes 35 are formed on both sides of the spacer 34. A ball screw 36 is provided at the center of the lid plate 33 so as to be located on the same axis as the axes of the first housing 23 and the first spindle 25.
Are rotatably supported via bearings 37.

A mounting plate 38 is fixed to an upper end of the first housing 23, and both side portions of the mounting plate 38 project outside the first housing 23 through through holes 35 of the spacer 34. A nut portion 39 is fixed through the center of the mounting plate 38, and a ball screw 36 is screwed to the nut portion 39 so as to be able to advance and retreat. The first feed motor 4 is provided on the lid plate 33.
0 is mounted via a bracket 41, and the motor shaft of the first feed motor 40 is connected to the ball screw 36 via a coupling 42.

When the ball screw 36 is rotated by the first feed motor 40, the rotational motion is converted into a linear motion by screwing with the nut 39, and the first housing 23 is moved up and down in the holding cylinder 22. Moved in the direction. Thus, the first grindstone 17 is fed and moved in a direction in which the first grindstone 17 comes into contact with and separates from the work 15.

As shown in FIGS. 3 and 4, a first housing 2 is provided between the first housing 23 and the holding cylinder 22.
1 as a first detent means for detent
A detent mechanism 43 is provided. First housing 2
A pair of guide cylinders 44 are erected and fixed on the upper surfaces on both sides of the mounting plate 38 on the upper side 3. A pair of bottomed cylindrical guide rods 45 are attached to the outer surface of the holding cylinder 22 via a support plate 46, and the guide rods 45 slide in the respective guide cylinders 44 in the vertical direction via static pressure radial bearings 47. Mated as possible.

The first detent mechanism 43 is equipped with a balance mechanism 48 for maintaining a balance when the first housing 23 moves. That is, cylinders 49 are respectively mounted on both guide cylinders 44, and an air supply port 5 for supplying compressed air is provided at the top of each cylinder 49.
0 is formed. Then, by supplying compressed air from the air supply port 50 into each of the cylinders 49, a levitation force is applied to the guide cylinder 44, and the weight of the first housing 23 and its related members is supported. Thereby, the first
When the first housing 23 is moved in the vertical direction by the feed motor 40, the load applied to the engaging portion between the ball screw 36 and the nut portion 39 is reduced, and the first housing 23 is moved.
Movement balance is maintained.

The first detent mechanism 43 is provided with a fine adjustment feed mechanism 51 for finely adjusting the first housing 23 in the vertical direction. That is, a plurality of air supply ports 52 are formed in both guide cylinders 44. Then, after the first housing 23 is moved by the first feed motor 40 and the first grindstone 17 is moved to a position corresponding to the workpiece 15, the selected air supply port 5 is selected.
Pressure air is blown from 2 toward the outer peripheral surface of the guide rod 45. As a result, the guide rod 45 is pressed around the axis of the ball screw 36 in the guide cylinder 44, and the first housing 23 is allowed to rotate slightly, and the rotation is performed via the nut portion 39 and the ball screw 36 through the rotation. The one housing 23 is finely moved in the axial direction.

Next, the structure of the second grindstone driving device 18 will be described in detail. As shown in FIG. 5, a support base 55 is fixed on the lower frame 12, a holding cylinder 57 is fixed through the center of the support base 55, and a cylindrical second housing 58 is provided therein with a hydrostatic radial. It is fitted and supported movably in the vertical direction via a bearing 59. In the center of the second housing 58, a second spindle 60 is rotatably supported via a hydrostatic radial bearing 61 and a hydrostatic thrust bearing 62, and the second grindstone 19 is mounted on the upper end of the second spindle 60. A grindstone table 63 for holding is provided.
A second rotation motor 67 is arranged in the second housing 58, and the second rotation motor 67 rotates the second grindstone 19 via the second spindle 60.

A flange 68 is provided near the upper end of the second spindle 60, and a plurality of communication holes 69 for communicating the upper space 62a and the lower space 62b of the hydrostatic thrust bearing 62 to the flange 68. Are formed.
Thereby, the upper and lower spaces 62a of the hydrostatic thrust bearing 62,
At 62b, the pressure difference of the compressed air is prevented from occurring,
When the second spindle 60 is rotated by the second rotation motor 67, it is possible to prevent the second spindle 60 from being vibrated.

As shown in FIG. 5, a second feed mechanism 70 as a second feed means is provided at the lower end of the holding cylinder 57. That is, a lid plate 71 is attached to the lower end of the holding cylinder 57, and one side of the lid plate 71 extends outward of the holding cylinder 57. Second housing 58 and second spindle 60
A ball screw 72 is rotatably supported on the cover plate 71 via a bearing 73 so that the ball screw 72 is located on the same axis as the axis.

An attachment plate 74 is attached to the lower end of the second housing 58, and one side of the attachment plate 74
5 project outside. A nut 76 is fixedly penetrated to the mounting plate 74, and a ball screw 72 is screwed into the nut 76. A second feed motor 77 is mounted on one upper surface of the cover plate 71, and its motor shaft is operatively connected to the ball screw 72 via pulleys 78 and 79 and a belt 80.

When the ball screw 72 is rotated by the second feed motor 77, the rotational motion is converted to a linear motion by screwing with the nut portion 76, and the second housing 58 is moved up and down in the holding cylinder 57. Moved in the direction. Thus, the second grindstone 19 is fed and moved in a direction in which the second grindstone 19 comes into contact with and separates from the work 15.

As shown in FIG. 5, the second housing 5
A second detent mechanism 81 as second detent means for detenting the second housing 58 is disposed between the holding cylinder 8 and the holding cylinder 57. A guide tube 82 is attached to one outer surface of the holding tube 57, and the guide tube 82 is slidable in a vertical direction along a guide rail 85 provided on the outer surface of the holding tube 57. A bottomed cylindrical guide rod 83 is fixed upright on one upper surface of the mounting plate 74 at the lower end of the second housing 58, and is slidably fitted in the guide cylinder 82 in the vertical direction via a hydrostatic radial bearing 84. Have been combined.

Next, the operation of the grinding machine configured as described above will be described. Now, in this grinding machine, when performing a grinding process, the second grindstone 19 of the second grindstone driving device 18 is fed upward by the second feed mechanism 70 while the work 15 is held by the work holding device 14. It is moved and comes into contact with the lower surface of the work 15. Further, the first grinding wheel driving device 1
The 6th first grindstone 17 is fed downward by the first feed mechanism 32 and is arranged close to the upper surface of the work 15.

In this state, the work 15 is rotated by a rotation motor (not shown) in the work holding device 14, and the grinding wheels 17, 19 are rotated by the rotation motors 29, 67.
, Respectively. Then, the first grindstone 17 is decelerated and fed toward the work 15 by the first feed mechanism 32, and the front and back surfaces of the work 15 are roughly ground simultaneously by the two grindstones 17 and 19.

Thereafter, the first grindstone 17 of the first grindstone driving device 16 is finely adjusted by the fine adjustment feeding mechanism 51 in units of 0.1 μm or less. Thereby, both the front and back surfaces of the work 15 are simultaneously precision ground by the two grindstones 17 and 19.

The effects that can be expected from the above embodiment will be described below. In this embodiment, the first grindstone driving device 16 is provided in a vertically upright state corresponding to the work holding device 14 that holds the work 15. The first grindstone driving device 16 has a holding cylinder 22 on the upper frame 13.
A first housing 23 movably supported in a vertical direction via a static pressure radial bearing 24, and a first spindle 25 rotatably supported in the first housing 23;
A first grindstone 17 held at an end of a first spindle 25 corresponding to the work 15 and a mechanism for converting a rotational motion into a linear motion are provided. A first feed mechanism 32 for bringing the 17 into and out of contact with the work 15 is provided.

For this reason, when a linear motion is applied to the first housing 23 by the first feed mechanism 32, the first housing 23 is moved up and down via the hydrostatic radial bearing 24 without receiving a large sliding resistance. Be moved. Therefore, the first grindstone 17 can be finely fed and moved to a position corresponding to the work 15, and the work 15 can be precisely ground.

In this embodiment, the first feed mechanism 32 comprises a motor 40, a ball screw 36, and a nut 39, and the ball screw 36 is arranged on the same axis as the first housing 23. For this reason, the first feed mechanism 3
Although the configuration of the first housing 23 is simple,
The sliding resistance acting on the
The first grindstone 17 can be finely fed stably.

In this embodiment, the first spindle 25 is provided inside the first housing 23 and includes the hydrostatic radial bearing 2.
6 and a hydrostatic thrust bearing 27.
For this reason, although the bearing configuration of the first spindle 25 is simple, the first spindle 25 is connected to the first housing 23.
Can be supported in a stable state, and the processing accuracy of the work 15 can be improved.

In this embodiment, a first detent mechanism 43 for detenting the first housing 23 is provided between the first housing 23 and the holding cylinder 22 on the upper frame 13. For this reason, the upper frame 13
The possibility that the first housing 23 supported by the upper holding cylinder 22 via the hydrostatic radial bearing 24 via unnecessary rotation is unnecessary can be reliably prevented by the first rotation preventing mechanism 43. One grindstone 17 can be precisely and minutely fed to a position corresponding to the work 15. In addition, since a floating force is applied to the guide cylinder 44 and the mounting plate 38 by each cylinder 49, backlash between the ball screw 36 and the nut 39 is eliminated. Therefore, the first grindstone 17 can be minutely fed more accurately.

In this embodiment, the first rotation preventing mechanism 43 is provided between the guide cylinder 44 provided on one of the first housing 23 and the holding cylinder 22 and the first housing 23 and the holding cylinder 22. A guide rod 45 is provided on the other side and is slidably fitted in a guide cylinder 44 via a static pressure radial bearing 47. For this reason, although the structure of the first detent mechanism 43 is simple, it is possible to reliably prevent unnecessary rotation of the first housing 23 without applying extra force such as sliding resistance. it can.

In this embodiment, the first detent mechanism 43 supports the weight of the first housing 23 and its related members to maintain the balance when the first housing 23 is moved by the first feed mechanism 32. Balance mechanism 48 for
Is provided. For this reason, the first housing 23 can be moved while maintaining the balance in the axial direction while the weights of the first housing 23 and the related members are supported by the balance mechanism 48, and the first grindstone 17 is moved to the work 15.
Can be more minutely fed to the position corresponding to.

In this embodiment, the first detent mechanism 43 allows the fine rotation of the first housing 23 and finely adjusts the first housing 23 in the vertical direction. Is provided. For this reason,
The first housing 23 can be fine-adjusted and moved by the fine-adjustment feed mechanism 51, and the first grindstone 17 can be fine-adjusted and fed to the position corresponding to the work 15 more accurately.

In this embodiment, a communication hole 31 for communicating the upper and lower spaces 27a, 27b of the hydrostatic thrust bearing 27 is formed in the flange portion 30 on the first spindle 25. For this reason, it is possible to prevent a possibility that vibration occurs in the first spindle 25 due to a pressure difference between the upper and lower spaces 27 a and 27 b of the hydrostatic thrust bearing 27, thereby improving the processing accuracy of the work 15. .

In the present embodiment, a second grindstone driving device 18 is provided on the side opposite to the first grindstone driving device 16 in a vertically upright state, corresponding to the work holding device 14. The second wheel driving device 18 has a second housing 58 supported by a holding cylinder 57 on the lower frame 12 via a static pressure radial bearing 59 so as to be movable in the vertical direction.
A second spindle 60 rotatably supported in the second housing 58; a second grindstone 19 held at an end of the second spindle 60 corresponding to the work 15; A mechanism for converting the second grinding wheel 19 into a workpiece 15 by moving the second housing 58 in the vertical direction.
And a second feed mechanism 70 that comes into contact with and separates from the second feed mechanism 70.

Therefore, the sliding resistance acting on each of the housings 23 and 58 accommodating and supporting the spindles 25 and 60 can be reduced in the pair of grindstone driving devices 16 and 18 disposed opposite to each other. Therefore, the grindstones 17 and 29 in both the grindstone driving devices 16 and 18 can be finely fed and moved, respectively, and the work 15 can be precisely ground from both front and back surfaces.

In this embodiment, the second feed mechanism 70 includes a motor 77, a ball screw 72, and a nut portion 76, and the ball screw 72 is disposed on the same axis as the second housing 58. For this reason, the second feed mechanism 7
Although the configuration of the second housing 58 is simple,
The sliding resistance acting on the
The second grindstone 19 can be finely fed stably.

In this embodiment, the second spindle 60 is provided with the hydrostatic radial bearing 6 in the second housing 58.
1 and a hydrostatic thrust bearing 62.
For this reason, despite the simple bearing configuration of the second spindle 60, the second spindle 60 is connected to the second housing 58.
Can be supported in a stable state, and the processing accuracy of the work 15 can be improved.

In this embodiment, between the second housing 58 and the holding cylinder 57 on the lower frame 12, a second rotation stopping mechanism 81 for stopping the rotation of the second housing 58 is provided. For this reason, the lower frame 12
The second housing 58 can reliably prevent the second housing 58 from rotating when the second housing 58 supported by the upper holding cylinder 57 via the static pressure radial bearing 59 is rotated. 19 can be minutely fed accurately to a position corresponding to the work 15.

In this embodiment, the second rotation preventing mechanism 81 is provided between the guide cylinder 82 provided on one of the second housing 58 and the holding cylinder 57 and the second housing 58 and the holding cylinder 57. A guide rod 83 is provided on the other side, and is slidably fitted in a guide cylinder 82 via a static pressure radial bearing 84. For this reason, although the structure of the second rotation preventing mechanism 81 is simple, unnecessary rotation of the second housing 58 can be reliably prevented without applying extra force such as sliding resistance. it can.

In this embodiment, a communication hole 69 for communicating the upper and lower spaces 62a, 62b of the hydrostatic thrust bearing 62 is formed in the flange 68 on the second spindle 60. For this reason, it is possible to prevent a possibility that vibration occurs in the second spindle 60 due to a pressure difference between the upper and lower spaces 62 a and 62 b of the hydrostatic thrust bearing 62, and it is possible to improve the processing accuracy of the work 15. .

This embodiment can be embodied with the following modifications. In the first rotation preventing mechanism 43 of the first grindstone driving device 16, the guide cylinder 44 is attached to the holding cylinder 22 and the guide rod 45 is attached to the first housing 23.

The second wheel driving device 18 is omitted, and only the first wheel driving device 16 is used to grind only one surface of the work 15. Supplying pressurized oil instead of pressurized air to each of the hydrostatic radial bearings 24, 26, 47, 59 and the hydrostatic thrust bearings 27, 62.

[0055]

The present invention is configured as described above, and has the following effects. According to the first aspect of the present invention, the sliding resistance acting on the housing accommodating and supporting the spindle can be reduced, and the grindstone can be finely moved so that the work can be precisely ground. Can be.

According to the second aspect of the present invention, the sliding resistance acting on the housing can be further reduced in spite of the simple construction of the feeding means, and the grinding wheel can be finely fed in a stable manner. can do.

According to the third aspect of the invention, the spindle can be supported in the housing in a stable state in spite of the simplicity of the bearing configuration of the spindle, and the machining accuracy of the work can be improved. Can be.

According to the fourth aspect of the present invention, in the pair of grinding wheel driving devices disposed opposite to each other, the sliding resistance acting on each housing accommodating and supporting the spindle can be reduced. The workpiece can be finely fed and moved, and the workpiece can be precisely ground from both sides.

According to the fifth aspect of the invention, the sliding resistance acting on the second housing can be further reduced in spite of the simple structure of the second feeding means, and the second grinding wheel Can be finely fed in a stable manner.

According to the sixth aspect of the present invention, the second spindle can be supported in the second housing in a stable state in spite of the simplicity of the bearing configuration of the second spindle. Processing accuracy can be improved.

According to the seventh aspect of the present invention, the possibility that the housing supported by the holding cylinder on the frame via the hydrostatic bearing is unnecessarily rotated is reliably prevented by the detent means. And the grindstone can be precisely and minutely fed to a position corresponding to the workpiece.

According to the eighth aspect of the present invention, unnecessary rotation of the housing can be ensured without the use of extra force such as sliding resistance, despite the simple structure of the detent means. Can be prevented.

According to the ninth aspect of the present invention, the housing can be moved while maintaining the balance in the axial direction while the weight of the housing and its related members are supported by the balance mechanism, and the grindstone can correspond to the workpiece. The minute feed can be performed even more accurately to the position where it is performed.

According to the tenth aspect of the present invention, the housing can be finely adjusted and moved by the fine adjustment feeding mechanism, so that the grindstone can be finely adjusted and fed to the position corresponding to the workpiece.

According to the eleventh aspect of the present invention, a pressure difference is generated between the upper and lower spaces of the hydrostatic bearing, whereby it is possible to prevent the possibility of vibration of the spindle, and to improve the machining accuracy of the workpiece. Can be.

According to the twelfth aspect, the possibility that the second housing, which is supported by the holding cylinder on the frame via the hydrostatic bearing, is unnecessarily rotated is reduced by the second detent means. Thus, the second grindstone can be precisely and minutely fed to a position corresponding to the workpiece.

According to the thirteenth aspect, although the structure of the second detent means is simple, an extra force such as sliding resistance acts on the rotation of the second housing. Can be reliably prevented.

According to the fourteenth aspect of the present invention, it is possible to prevent the occurrence of vibration in the second spindle due to the pressure difference between the upper and lower spaces of the hydrostatic bearing.
Work accuracy of the workpiece can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a grinding machine of the present invention.

FIG. 2 is a side view of the grinding machine.

FIG. 3 is an enlarged sectional view of a main part of the first grindstone driving device.

FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is an enlarged sectional view of a main part showing a second grindstone driving device and a work holding device.

[Explanation of symbols]

11 ... frame, 12 ... lower frame, 13 ... upper frame, 14 ... work holding device, 15 ... work, 16 ... first grindstone drive device, 17 ... first grindstone, 18 ... second grindstone drive device, 19 ... second Grinding wheel, 22 ... holding cylinder, 23 ... first housing, 24 ... static pressure radial bearing, 25 ... first spindle, 26 ... static pressure radial bearing, 27 ... static pressure thrust bearing, 27a ... upper space, 27b ... lower space, 29 ... first
Rotating motor, 30: flange portion, 31: communication hole, 32
... First feed mechanism as first feed means, 36... Ball screw, 39... Nut part, 40.
First detent mechanism as first detent means, 44 guide cylinder, 45 guide rod, 47 static pressure radial bearing, 48 balance mechanism, 49 cylinder, 51 fine adjustment feed mechanism, 52 air supply Mouth, 57 ... holding cylinder, 58 ...
Second housing, 59 ... hydrostatic radial bearing, 60 ... second
Spindle, 61: hydrostatic radial bearing, 62: hydrostatic thrust bearing, 62a: upper space, 62b: lower space, 67
.., A second rotation motor, 68, a flange portion, 69, a communication hole, 70, a second feed mechanism as second feed means, 72,
Ball screw, 76 nut part, 77 second feed motor, 81 second stop mechanism as second stop means, 82 guide cylinder, 83 guide rod, 84 hydrostatic radial bearing, 86 air Supply port.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuo Nakajima 100 Fukuno-cho, Higashi-Tonami-gun, Toyama Prefecture Inside the Tohei Plant, Hihira Toyama Co., Ltd. in the factory

Claims (14)

[Claims] 1. A work holding device for holding a work, and a grindstone driving device arranged in an upright state corresponding to the work holding device, wherein the grindstone driving device includes a holding device on a frame. A housing supported on the cylinder movably in the vertical direction via a static pressure bearing, a spindle rotatably supported in the housing, a grindstone held at an end of the spindle corresponding to the work; A grinding machine comprising: a mechanism for converting a rotary motion into a linear motion; and a feeding means for moving a housing up and down to move a grinding wheel toward and away from a workpiece. 2. The grinding machine according to claim 1, wherein said feeding means comprises a motor, a ball screw and a nut, and wherein the ball screw is disposed on the same axis as the housing. 3. The grinding machine according to claim 1, wherein the spindle is supported in the housing via a hydrostatic bearing. 4. A second vertically arranged upright state on the opposite side of the grindstone driving device corresponding to the work holding device.
A grinding wheel drive unit, the second wheel drive unit includes a second housing supported by a holding cylinder on a frame via a static pressure bearing so as to be movable in a vertical direction, and a rotatable interior of the second housing. A second spindle, which is rotatably supported on the second spindle, a second grindstone held at the end of the second spindle corresponding to the workpiece, and a mechanism for converting a rotational motion into a linear motion. The grinding machine according to any one of claims 1 to 3, further comprising: a second feeding unit configured to move the second grindstone toward and away from the workpiece. 5. The grinding machine according to claim 4, wherein said second feed means comprises a motor, a ball screw and a nut, and wherein the ball screw is disposed on the same axis as the second housing. 6. The second spindle is supported in the second housing through a hydrostatic bearing in the second housing.
Grinding machine according to 1. 7. The grinding machine according to claim 1, further comprising a detent means for detenting the housing between the housing and the holding cylinder on the frame. . 8. The detent means is provided on a guide cylinder provided on one of the housing and the holding cylinder, and is provided on the other of the housing and the holding cylinder, and slides in the guide cylinder via a hydrostatic bearing. The grinding machine according to claim 7, comprising a guide rod movably fitted. 9. The rotation preventing device according to claim 7, further comprising a balance mechanism for supporting the weight of the housing and its related members to maintain a balance when the housing is moved by the feeding device. Grinding machine. 10. The device according to claim 7, wherein the rotation preventing means includes a fine adjustment feeding mechanism for finely moving the housing in a vertical direction while allowing a slight rotation of the housing. The grinder according to claim 1. 11. A flange on the spindle includes:
The grinding machine according to claim 3, wherein a communication hole for communicating the upper and lower spaces of the hydrostatic bearing is formed. 12. The device according to claim 4, further comprising a second detent means for detenting the second housing between the second housing and the holding cylinder on the frame. Grinding machine according to item. 13. The second rotation preventing means is provided on a guide cylinder provided on one of the second housing and the holding cylinder, and is provided on the other of the second housing and the holding cylinder. 13. The grinding machine according to claim 12, comprising a guide rod slidably fitted via a pressure bearing. 14. The grinding machine according to claim 6, wherein a communication hole for communicating the upper and lower spaces of the hydrostatic bearing is formed in the flange portion on the second spindle.