JP2014042945A - Work holding device and processing machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work holding device which is applied to a structure where a rotation shaft including a vacuum chuck mechanism rotates at a high speed and achieves long life and high accuracy, and to provide processing machinery.SOLUTION: A work holding device includes: a body 11; a rotation shaft 20 which is rotatably supported at the body and has a first passage 21 therein; a vacuum chuck mechanism 30 attached to one end of the rotation shaft; and an air suction circuit which is provided at the other end side of the rotation shaft through a rotary joint 50. The rotary joint includes: a non contact seal member 52 which is provided at the body having a small seal gap 51 between itself and the outer peripheral surface of the other end of the rotation shaft; a second passage 54 which is formed in the non contact seal member and causes the air suction circuit and the seal gap 51 to communicate with each other; an annular third passage 55 which is formed at the outer periphery of the other end of the rotation shaft and communicates with the seal gap 51; and a fourth passage 56 which is formed at the rotation shaft and causes the third passage and the first passage to communicate with each other.

Description

  The present invention relates to a workpiece holding device that holds a workpiece by vacuum suction and a processing machine including the workpiece holding device.

  In a processing machine that processes a workpiece while rotating the workpiece by rotating the rotating shaft in a state where the vacuum chuck mechanism is attached to the rotating shaft and the workpiece is sucked and held by the vacuum chuck mechanism, the rotating shaft and A vacuum rotary joint is provided between the main body to be supported, and a mechanism for sucking air from the vacuum chuck mechanism from the main body through the vacuum rotary joint is required.

For example, in Patent Document 1, an annular groove is formed on the inner peripheral surface of a sliding bearing member in a structure in which a spindle having a suction plate attached to the tip is rotatably supported on a housing via a sliding bearing member. The groove is connected to the air suction line through a flow path formed in the housing, and a flow path that opens to the annular groove and communicates with the suction port of the suction plate is formed inside the spindle.
In such a configuration, when air is sucked by the air suction line, the suction port of the suction plate is sucked through the flow path formed in the housing, the annular groove, and the flow path inside the spindle. Can be adsorbed.

Further, in the work holding device shown in FIG. 5, the main body 11, the rotary shaft 20 rotatably supported by the main body 11 and having the first flow path 21 along the internal axis direction, and one end of the rotary shaft 20 are attached. A vacuum chuck mechanism 30 having an intake hole 32 communicating with the first flow path 21, and a rotary joint 50 provided on the other end side of the rotary shaft 20, and the air of the vacuum chuck mechanism 30 is passed through the first flow path 21. And air suction means 80 for suction.
The rotary joint 50 includes a fixed cylinder 81 fixed to the main body 11 side, a tube 82 whose front end is fixed to the fixed cylinder 81 and whose rear end is connected to the air suction means 80, and fixed on the opposite side of the tube 82. A rotary nozzle 84 that is rotatably provided in the cylinder 81 via a bearing 83 and rotates together with the rotary shaft 20, and a seal member 85 provided between the outer periphery of the rotary nozzle 84 and the fixed cylinder 81 are provided. .

  Therefore, when air is sucked by the air suction means 80, the suction hole 32 of the vacuum chuck mechanism 30 is sucked through the tube 82, the rotary nozzle 84 and the first flow path 21 of the rotary shaft 20. Can be adsorbed on.

Japanese Patent Application Laid-Open No. 11-151693

  In the above-described prior art, in Patent Document 1, the spindle rotates in a state of being in close contact with the sliding bearing member so that air does not leak from the rotary joint, and the work holding device shown in FIG. However, since the seal member is interposed between the fixed cylinder and the rotating nozzle, the structure cannot be applied to a processing machine in which the spindle rotates at a high speed.

  In particular, in the case of the work holding device shown in FIG. 5, since the seal member is used, it is likely to be deteriorated due to wear. Therefore, although it depends on use conditions, it can be used only for about one year, and the lifetime becomes a problem. Furthermore, in a market where high-precision machining is required, the wear of the seal member and the rolling vibration of the bearing affect the machining accuracy, so the application may be limited for reasons of accuracy.

  The object of the present invention is to solve such problems and to be applied to a configuration in which a rotary shaft equipped with a vacuum chuck mechanism rotates at a high speed, and to achieve a long life and high accuracy, and a work holding device using the same It is to provide a processing machine.

  The work holding device according to the present invention includes a main body, a rotary shaft that is rotatably supported by the main body and has a first flow path along an internal axis direction, and is attached to one end of the rotary shaft and communicates with the first flow path. A work holding device comprising: a vacuum chuck mechanism having a suction hole for performing suction; and an air suction means provided on the other end side of the rotary shaft via a rotary joint for sucking air of the vacuum chuck mechanism through the first flow path The rotary joint includes a non-contact seal member provided in the main body with a slight seal gap with respect to the outer peripheral surface of the other end of the rotary shaft, and the air suction means formed in the non-contact seal member And a second flow path that communicates with the seal gap, an annular third flow path that communicates with the seal gap formed on the outer periphery of the other end of the rotary shaft, and the third flow path that is formed on the rotary shaft. And the first flow path And a fourth channel for communicating, characterized in that.

According to such a configuration, when air is sucked by the air suction means, the air of the vacuum chuck mechanism is sucked through the second flow path, the third flow path, the fourth flow path, and the first flow path. It can be adsorbed on a vacuum chuck.
At this time, a slight seal gap is formed between the second flow path and the third flow path, that is, between the outer peripheral surface of the other end of the rotating shaft and the non-contact seal member. A function as a contact seal can be provided. That is, even if atmospheric air is sucked from the outside through the seal gap, the degree of vacuum can be increased to a level at which the workpiece can be held by the vacuum chuck mechanism.
In this state, even if the rotating shaft rotates, the rotating shaft and the non-contact seal member do not come into contact with each other, so that the conventional problem can be solved. That is, the present invention can be applied to a configuration in which a rotary shaft provided with a vacuum chuck mechanism rotates at a high speed, and can achieve a long life and high accuracy.

In the workpiece holding device according to the present invention, it is preferable that a seal gap between the outer peripheral surface of the other end of the rotating shaft and the non-contact seal member is set to 1 μm to 20 μm. The seal gap may be within the above range, but is preferably 8 to 17 μm, more preferably 10 to 15 μm.
According to such a configuration, the seal gap between the outer peripheral surface of the other end of the rotating shaft and the non-contact seal member is set to 1 μm to 20 μm, so that the function as a non-contact seal can be sufficiently achieved.

In the work holding device of the present invention, it is preferable that the work holding device further includes an air supply unit that supplies air to the vacuum chuck mechanism through the rotary joint, and a switching unit that switches between the air suction unit and the air supply unit.
Normally, when a workpiece is picked up by a vacuum chuck mechanism and the workpiece is processed in this state and then removed from the vacuum chuck mechanism, the workpiece may not be removed from the vacuum chuck mechanism simply by cutting the vacuum.

  In the present invention, it is provided with air supply means for supplying air to the vacuum chuck mechanism through a rotary joint, and switching means for switching between these air suction means and air supply means, so when removing the workpiece from the vacuum chuck mechanism, When switching from the air suction means to the air supply means by the switching means, air is supplied to the vacuum chuck mechanism through the second flow path, the third flow path, the fourth flow path, and the first flow path. Can be removed. Therefore, processing using the vacuum chuck mechanism can be performed efficiently.

In the workpiece holding device of the present invention, it is preferable that an air bearing mechanism is provided between the main body and the rotating shaft to support the rotating shaft in a non-contact state with air.
According to such a structure, since the rotating shaft is supported by the air bearing mechanism, the rotating shaft can be rotated at high speed. Therefore, machining suitable for high-speed rotation of the workpiece can be realized.

A processing machine according to the present invention includes any one of the workpiece holding devices described above.
According to such a structure, the processing machine which has the effect mentioned above can be provided.

The perspective view which shows the processing machine which concerns on embodiment of this invention. Sectional drawing which shows the workpiece holding apparatus in the said embodiment. FIG. 3 is a cross-sectional view taken along arrow III in FIG. 2. The figure which shows the air circuit of the said embodiment. Sectional drawing which shows the workpiece holding apparatus using the conventional rotary joint.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Configuration of Embodiment>
As shown in FIG. 1, the processing machine of this embodiment includes a bed 1 and a saddle provided on the upper surface side of the bed 1 so as to be movable in the front-rear direction (X-axis direction) via an X-axis drive mechanism 2. 3, a tool spindle device 4 provided on the saddle 3 so as to be movable in the vertical direction (Y-axis direction) via a Y-axis drive mechanism (not shown), and a Z-axis drive mechanism 8 on the other side of the upper surface of the bed 1. And a work holding device 10 that holds the work W and is provided so as to be movable in the left-right direction (Z-axis direction).

  The tool spindle device 4 includes a motor 5, a tool spindle 6 that is rotationally driven by the motor 5, and a tool 7 that is detachably attached to the tool spindle 6.

  As shown in FIG. 2, the work holding device 10 includes a main body 11, a rotary shaft 20 that is rotatably supported by the main body 11 and has a first flow path along the internal axial direction, and one end of the rotary shaft 20. A vacuum chuck mechanism 30 having an intake hole 32 that is attached and communicates with the first flow path 21, a rotation drive source 40 that is provided on the other end side of the rotation shaft 20 and that rotates the rotation shaft 20, and the other end of the rotation shaft 20. An air circuit 60 is provided on the side through a rotary joint 50 and sucks air from the vacuum chuck mechanism 30 through the first flow path 21 and supplies air to the vacuum chuck mechanism 30.

  The rotary shaft 20 includes a shaft portion 22 having a predetermined length having a first flow path 21 along the internal axial direction, and a flange portion 23 provided in the middle of the shaft portion 22 and having a diameter larger than the diameter of the shaft portion 22. Have

Between the main body 11 and the rotating shaft 20, bearing members 12, 13, and 14 constituting an air bearing mechanism that supports the rotating shaft 20 in a non-contact state with air are provided.
The bearing member 12 is formed with an inner diameter having a predetermined radial gap 15 between the outer peripheral surface of the shaft portion 22 and has an air ejection hole 12 </ b> A through which air is ejected into the radial gap 15.
The bearing member 13 is formed with an inner diameter having a predetermined radial gap 15 between the outer peripheral surface of the shaft portion 22, and has an air ejection hole 13 </ b> A for ejecting air into the radial gap 15. Further, the bearing member 13 has a predetermined thrust gap 16 and an air ejection hole 13 </ b> B for ejecting air into the thrust gap 16 between the end face of the flange portion 23.
The bearing member 14 has a predetermined thrust gap 16 and an air ejection hole 14 </ b> B that ejects air into the thrust gap 16 between the end face of the flange portion 23.

  The main body 11 has an air supply port 17 formed therein, and an air supply that communicates from the air supply port 17 to the air ejection holes 12A, 13A, 13B, and 14B of the bearing members 12, 13, and 14 therein. A path 18 is formed. An air source 19 is connected to the air supply port 17.

  The vacuum chuck mechanism 30 includes a suction plate 31 provided at one end of the rotary shaft 20, a suction hole 32 opened on the suction surface (surface that sucks the workpiece W) of the suction plate 31, and the suction plate 31. A communication path 33 that is formed and communicates with the first flow path 21 of the rotary shaft 20 and the intake hole 32 is configured.

  The rotation drive source 40 is configured by a motor including a rotor 41 fixed to the other end of the rotary shaft 20 and a stator 42 fixed to the main body 11 via a gap on the outer periphery of the rotor 41.

  As shown in FIG. 3, the rotary joint 50 includes a ring-shaped non-contact seal member 52 provided with a slight seal gap 51 with respect to the outer peripheral surface of the other end of the rotary shaft 20, and the non-contact seal. A fixing ring 53 that fixes the member 52 to the main body 11, a second flow path 54 that is formed along the radial direction in the fixing ring 53 and the non-contact seal member 52 and communicates the air circuit 60 and the seal gap 51, and rotation An annular third flow path 55 formed on the outer periphery of the other end of the shaft 20 that communicates (opens) with the seal gap 51 and the third flow path 55 and the first flow path 21 communicate with each other through the center of the rotary shaft 20. And a fourth flow path 56 formed so as to penetrate the rotary shaft 20.

Here, the non-contact seal member 52 is constituted by a low friction material, in this embodiment, a carbon bush. The low friction material is not limited to carbon, but may be Teflon (registered trademark) or molybdenum.
In addition, the seal gap 51 between the outer peripheral surface of the other end of the rotary shaft 20 and the non-contact seal member 52 is set in a range of 1 μm to 20 μm, in this embodiment, 13 μm. If the seal gap 51 is set small, the air leakage is reduced, but the production is difficult. On the other hand, if the seal gap 51 is set large, the manufacture becomes easy, but the air leakage increases. In the present embodiment, 13 μm is set as a compromise between ease of manufacture and leakage. The seal gap 51 may be within the above range, but is preferably 8 to 17 μm, and more preferably 10 to 15 μm.

  As shown in FIG. 4, the air circuit 60 includes an air suction circuit 61 as air suction means for sucking air from the vacuum chuck mechanism 30 through the rotary joint 50, and air for supplying air to the vacuum chuck mechanism 30 through the rotary joint 50. An air supply circuit 67 as supply means, and an electromagnetic switching valve 70 as switching means for switching between the air suction circuit 61 and the air supply circuit 67 are provided.

  The air suction circuit 61 is configured by connecting a compressed air source (original pressure: 7 kgf / cm 2) 62, a filter 63, a pressure reducing valve 64, an electromagnetic switching valve 65, and a diffuser type vacuum generator 66 in this order. The diffuser type vacuum generator 66 has a nozzle (primary side) and a diffuser (exhaust side) connected in series, and a suction path (secondary side) is joined to this connecting portion. When compressed air is supplied from the primary side, the compressed air discharged from the nozzle expands to reduce the pressure at the connecting portion. Then, air flows into the low-pressure part from the secondary side, is carried along with the compressed air discharged from the nozzle, and is exhausted through the diffuser. That is, by supplying compressed air from the primary side, the secondary side is sucked and evacuated.

The air supply circuit 67 shares the compressed air source (original pressure: 7 kgf / cm 2) 62 and the filter 63 with the air suction circuit 61, branches from between the filter 63 and the pressure reducing valve 64, and includes the pressure reducing valve 68 and the electromagnetic valve 69. It is configured by connecting sequentially.
The electromagnetic switching valve 70 as switching means is inserted between the air suction circuit 61 and the air supply circuit 67 and the rotary joint 50, and connects either the air suction circuit 61 or the air supply circuit 67 to the rotary joint 50.

<Operation and Effect of Embodiment>
In the machine tool having such a configuration, in order to attract the workpiece W to the vacuum chuck mechanism 30, the electromagnetic valve 69 is closed in the air circuit 60 of FIG. Compressed air is supplied to the primary side, and the electromagnetic switching valve 70 is opened (state shown in FIG. 4). Then, since the air of the vacuum chuck mechanism 30 is sucked through the second flow path 54, the third flow path 55, the fourth flow path 56 of the rotary joint 50, and the first flow path 21 of the rotary shaft 20, the workpiece W is It can be adsorbed to the vacuum chuck mechanism 30.

  At this time, a slight seal gap 51 is formed between the second flow path 54 and the third flow path 55, that is, between the outer peripheral surface of the other end of the rotating shaft 20 and the non-contact seal member 52. Therefore, it can have a function as a non-contact seal. In particular, since the seal gap 51 between the outer peripheral surface of the other end of the rotary shaft 20 and the non-contact seal member 52 is set to 13 μm, the function as a non-contact seal can be sufficiently achieved. Therefore, even if atmospheric air is sucked from the outside through the seal gap 51, the degree of vacuum can be increased to a level at which the workpiece W can be held by the vacuum chuck mechanism 30.

In this state, the workpiece W is processed by the tool 7 while rotating the rotation shaft 20 by driving the rotation drive source 40. At this time, even if the rotating shaft 20 rotates, the rotating shaft 20 and the non-contact seal member 52 do not come into contact with each other, so that the conventional problem can be solved. That is, the present invention can be applied to a configuration in which the rotary shaft 20 provided with the vacuum chuck mechanism 30 rotates at a high speed, and a long life and high accuracy can be achieved.
In particular, in the present embodiment, an air bearing mechanism (bearing members 12, 13, and 14) that supports the rotary shaft 20 in a non-contact state by air is provided between the main body 11 and the rotary shaft 20. The rotating shaft 20 can be rotated at high speed. Therefore, machining suitable for high-speed rotation of the workpiece W can be realized.

  In the present embodiment, since the non-contact seal member 52 is made of a low friction material (carbon bush), an inclined load acts on the rotary shaft 20 during work processing, and the non-contact seal is inclined. Even if it contacts the member 52, it can prevent that rotation of the rotating shaft 20 falls extremely. Further, even if the non-contact seal member 52 is damaged due to the rotation of the rotary shaft 20, it can be repaired by replacing only the non-contact seal member 52.

  In order to release the workpiece W from the vacuum chuck mechanism 30 after machining the workpiece W, the electromagnetic switching valve 70 is closed (in the right chamber in FIG. 4), and the electromagnetic switching valve 65 is switched to change the vacuum generator 66. The supply of compressed air to is stopped, and the solenoid valve 69 is switched to open. Then, air is supplied to the vacuum chuck mechanism 30 through the second flow path 54, the third flow path 55, the fourth flow path 56 of the rotary joint 50, and the first flow path 21 of the rotary shaft 20. The vacuum chuck mechanism 30 can be released. Therefore, processing using the vacuum chuck mechanism 30 can be performed efficiently.

<Modification>
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In the embodiment, the rotary shaft 20 includes the shaft portion 22 having a predetermined length having the first flow path 21 therein, and the flange portion 23 provided in the middle of the shaft portion 22 and having a diameter larger than the diameter of the shaft portion 22. However, the present invention is not limited to this, and may be a structure that is rotatably supported by a ball bearing or the like.

  In the above-described embodiment, the tool spindle device 4 can move in the X-axis direction and the Y-axis direction and the workpiece holding device 10 can move in the Z-axis direction as a processing machine. However, the present invention is not limited to this. . In short, any structure may be used as long as the tool spindle device 4 and the work holding device 10 can move relative to each other in two dimensions (two-axis direction) or three dimensions (three-axis direction).

The structure of each axis moving mechanism of the above-described embodiment, that is, the X-axis drive mechanism 2, the Y-axis drive mechanism (not shown), and the Z-axis drive mechanism 8 is not particularly limited. It may be a feeding mechanism using
In the above embodiment, a motor is used as the rotational drive source 40 of the rotating shaft 20, but the present invention is not limited to this. For example, an air turbine structure in which a turbine is attached to the rotating shaft 20 and rotated by air. May be.

  The present invention can be applied not only to general processing machines but also to ultraprecision machine tools such as ultraprecision aspherical processing machines.

10 ... Work holding device,
11 ... body,
12, 13, 14 ... bearing member (air bearing mechanism),
20 ... rotating shaft,
21 ... 1st flow path,
30 ... Vacuum chuck mechanism,
32 ... Intake hole,
50: Rotary joint,
51. Seal gap,
52 ... Non-contact sealing member,
54. Second flow path,
55. Third flow path,
56 ... 4th flow path,
61 ... Air suction circuit (air suction means),
67 ... Air supply circuit (air supply means),
70 ... Electromagnetic switching valve (switching means)
W ... Work.

Claims (5)

A vacuum chuck mechanism having a main body, a rotary shaft that is rotatably supported by the main body and has a first flow path along an internal axis direction, and an intake hole that is attached to one end of the rotary shaft and communicates with the first flow path And a work holding device comprising air suction means provided on the other end side of the rotary shaft via a rotary joint for sucking air of the vacuum chuck mechanism through the first flow path,
The rotary joint has a slight seal gap with respect to the outer peripheral surface of the other end of the rotary shaft, a non-contact seal member provided on the main body, the air suction means formed on the non-contact seal member, and the A second flow path communicating with the seal gap, an annular third flow path communicating with the seal gap formed on the outer periphery of the other end of the rotary shaft, the third flow path formed on the rotary shaft, and the A fourth flow path communicating with the first flow path;
A workpiece holding device characterized by that. The work holding apparatus according to claim 1,
A seal gap between the outer peripheral surface of the other end of the rotating shaft and the non-contact seal member is set to 1 μm to 20 μm,
A workpiece holding device characterized by that. In the workpiece holding device according to claim 1 or 2,
Air supply means for supplying air to the vacuum chuck mechanism through the rotary joint;
A switching means for switching between the air suction means and the air supply means,
A workpiece holding device characterized by that. In the workpiece holding device according to any one of claims 1 to 3,
Between the main body and the rotating shaft, an air bearing mechanism that supports the rotating shaft in a non-contact state by air is provided.
A workpiece holding device characterized by that.   The processing machine provided with the workpiece holding apparatus in any one of Claims 1-4.

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