JP2017009068A - Fluid pressure actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure actuator enabling movement and rotation of a rod simultaneously, and enabling compact design.SOLUTION: A fluid pressure actuator includes: a cylinder 2; a piston 3 moving inside the cylinder 2; a rod 4 connected to one end side of the piston 3, and moving integrally with the piston 3 in a state of projecting to the outside of the cylinder 2 from a first shaft hole 7 provided in the cylinder 2; a shaft 11 connected to the other end side of the piston 3, and moving integrally with the piston 3 in a state of projecting to the outside of the cylinder 2 from a second shaft hole 13 provided in the cylinder 2; a rotor 15 attached to the outer peripheral part of the shaft 11; and a rotational drive part 12 having a stator 16 surrounding the periphery of the rotor 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fluid pressure actuator.

  For example, in a die bonding process or a mounting process of a semiconductor chip, a fluid pressure actuator that slides a rod attached to the tip of a tool that holds the semiconductor chip in the vertical direction is used (see, for example, Patent Document 1).

  Specifically, when an air pressure actuator that differentials with air (air) is used as the fluid pressure actuator, the piston connected to the rod is adjusted inside the cylinder while adjusting the pressure of the air introduced into the cylinder. Control the slide position.

  In the air pressure actuator, an air bearing (hydrostatic air bearing) is formed by the air flowing from the pressure chamber in the cylinder into the gap between the cylinder and the piston. As a result, the piston is slidably supported in a non-contact state with the cylinder.

JP 2004-301138 A

  By the way, the fluid pressure actuator described in Patent Document 1 has a configuration in which the rod is rotationally driven integrally with the guide flange by a driving force transmitted from a rotational drive source such as a servo motor to the guide flange via a gear. Yes.

  In this configuration, the mechanism for sliding the rod is non-contact driving, but the mechanism for rotating the rod is not non-contact driving. Therefore, the above-described highly accurate load control and position control of the semiconductor chip are performed. Is disadvantageous.

  Further, in the fluid pressure actuator described in Patent Document 1, it is necessary to provide the rotation drive source described above outside, and since the rotation drive source cannot be directly attached to the rod, a mechanism for transmitting the drive force is necessary. It becomes. In this case, there is a problem that not only the apparatus becomes complicated, but also the apparatus becomes large.

  One aspect of the present invention has been proposed in view of such a conventional situation, and is a fluid pressure actuator capable of simultaneously moving and rotating a rod and enabling a compact design. One of the purposes is to provide.

In order to achieve the above object, the present invention provides the following means.
[1] A fluid pressure actuator according to an aspect of the present invention includes a cylinder, a piston that moves inside the cylinder, a first shaft that is connected to one end of the piston and provided in the cylinder. A rod that moves integrally with the piston in a state of projecting from the hole to the outside of the cylinder, and connected to the other end side of the piston, and from a second shaft hole provided in the cylinder, A shaft that moves integrally with the piston in a state of projecting to the outside, a rotor that is attached to an outer periphery of the shaft, and a rotation drive unit that includes a stator surrounding the rotor, and the cylinder, A first fluid bearing is formed by the fluid flowing into the gap between the piston and the fluid flowing into the gap between the first shaft hole and the rod. The second fluid bearing is formed, and the third fluid bearing is formed by the fluid flowing into the gap between the second shaft hole and the shaft.

[2] In the fluid pressure actuator according to [1], a position where the second fluid bearing of the first shaft hole is formed and a third fluid bearing of the second shaft hole are formed. Each of the positions may be provided with a porous restriction.

[3] In the fluid pressure actuator according to [1] or [2], the stator may be configured such that the total length of the stator is longer than that of the rotor.

[4] In the fluid pressure actuator according to [1] or [2], the rotor may be configured such that the entire length of the rotor is longer than that of the stator.

[5] The fluid pressure actuator according to any one of [1] to [4], wherein the fluid is allowed to flow into a first pressure chamber located on the shaft side across the piston in the cylinder. A first port, a second port for allowing fluid to flow into the second pressure chamber located on the rod side across the piston in the cylinder, and a position detection unit attached to the tip of the shaft; Based on the detection result of the position detection unit, the pressure of the fluid flowing into the first pressure chamber through the first port and the second pressure chamber through the second port. The structure provided with the pressure adjustment part which adjusts the pressure of the fluid may be sufficient.

[6] In the fluid pressure actuator according to [5], the pressure adjusting unit may be connected via the first port in consideration of a change in magnetic attraction force acting between the rotor and the stator. The configuration may be such that the pressure of the fluid flowing into the first pressure chamber and the pressure of the fluid flowing into the second pressure chamber via the second port are adjusted.

[7] The fluid pressure actuator according to any one of [1] to [6], wherein the fluid is air.

  As described above, according to one aspect of the present invention, it is possible to provide a fluid pressure actuator capable of simultaneously moving and rotating a rod and enabling a compact design.

It is sectional drawing which shows one structural example of the fluid pressure actuator which concerns on embodiment of this invention. It is sectional drawing which shows another structural example of the fluid pressure actuator which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that, in the drawings used in the following description, in order to make each component easy to see, the component may be schematically illustrated, and depending on the component, the dimensional scale may be different.

  First, as an embodiment of the present invention, for example, a fluid pressure actuator 1A shown in FIG. 1 will be described. FIG. 1 is a cross-sectional view showing the configuration of the fluid pressure actuator 1A.

  As shown in FIG. 1, the fluid pressure actuator 1A is an air pressure actuator using air (air) K as a differential fluid. The fluid pressure actuator 1 </ b> A includes a cylinder 2, a piston 3 that slides (moves) inside the cylinder 2, and a rod 4 that slides (moves) integrally with the piston 3 by being connected to one end (lower end) side of the piston 3. And. In this embodiment, the case where the rod 4 slides (moves) in the vertical direction is illustrated, but the moving direction of the rod 4 is not particularly limited.

  The cylinder 2 has a substantially cylindrical cylinder housing 5. A bore hole 6 is formed in the cylinder housing 5 along the axial direction. The cylinder housing 5 has a structure in which one end (upper end) side and the other end (lower end) side of the bore hole 6 are closed in a state where the piston 3 is inserted into the bore hole 6. Further, a first shaft hole 7 through which the rod 4 passes is provided at the lower end of the cylinder housing 5.

  As a result, the inside of the cylinder 2 has a first pressure chamber P1 located on the opposite side (upper side) of the rod 4 across the piston 3 and a first pressure chamber P1 located on the rod 4 side (lower side) across the piston 3. It is divided into two pressure chambers P2.

  Connected to the side surface of the cylinder housing 5 are a first port 8 through which air K flows into the first pressure chamber P1 and a second port 9 through which air K flows into the second pressure chamber P2. .

  The piston 3 is supported so as to be slidable (movable) in the vertical direction in a non-contact state with the cylinder 2 via an air bearing (hydrostatic air bearing). Specifically, a first air bearing (first fluid bearing) B1 is formed by the air K flowing into the gap between the cylinder 2 and the piston 3. In order to form the first air bearing B1, the gap between the cylinder 2 (bore hole 6) and the piston 3 is preferably set to about 5 to 12 μm.

  The rod 4 slides up and down via a second air bearing (second fluid bearing) B2 in a state of projecting from the first shaft hole 7 to the outside (downward) of the cylinder 2 (cylinder housing 5). (Movement) It is supported freely. The second fluid bearing B <b> 2 is formed by air K that flows into the gap between the first shaft hole 7 and the rod 4. A first porous throttle 10 is provided at a position where the second fluid bearing B2 of the first shaft hole 7 is formed. As a result, the air supply ports are uniformly distributed over the entire bearing surface, and it is possible to reduce the consumption of air K and to obtain high rigidity.

  The fluid pressure actuator 1 </ b> A includes a shaft 11 that slides (moves) integrally with the piston 3 by being connected to the other end (upper end) side of the piston, and a rotation driving unit 12 that rotationally drives the shaft 11. Further, a second shaft hole 13 through which the shaft 11 passes is provided at the upper end of the cylinder housing 5.

  The shaft 11 slides up and down via a third air bearing (third fluid bearing) B3 in a state of projecting from the second shaft hole 13 to the outside (upward) of the cylinder 2 (cylinder housing 5). (Movement) It is supported freely. The third fluid bearing B <b> 3 is formed by the air K that flows into the gap between the second shaft hole 13 and the shaft 11. A second porous throttle 14 is provided at a position where the third fluid bearing B3 of the second shaft hole 13 is formed. As a result, the air supply ports are uniformly distributed over the entire bearing surface, and it is possible to reduce the consumption of air K and to obtain high rigidity.

  The rotation drive unit 12 includes a rotor 15 attached to the outer periphery of the shaft 11 and a stator 16 surrounding the rotor 15. A magnet (not shown) provided on the rotor 15 and a coil (not shown) provided on the stator 16 are arranged to face each other. The stator 16 is formed in a cylindrical shape so as to have the same diameter as the cylinder 2 and is integrally attached to the other end (upper end) side of the cylinder 2. The rotor 15 is attached to a substantially central portion of the shaft 11. Further, the entire length of the stator 16 is longer than that of the rotor 15.

  In the rotary drive unit 12, when a drive current is supplied to the coil of the stator 16, a magnetic field is generated in the coil, and the shaft 11 is brought into non-contact by an electromagnetic action with the magnet of the rotor 15 facing the coil. Rotation drive.

  The fluid pressure actuator 1 </ b> A includes an encoder (position detection unit) 17 attached to the tip (upper end) of the shaft 11. The encoder 17 includes a scale 18 provided on the shaft 11 side and a head (not shown) provided on a case 19 surrounding the shaft 11. In the encoder 17, the head detects the position information of the scale 18 serving as a ruler, and outputs the detection result to the outside. In the present embodiment, the position information detected by the encoder 17 detects the slide position of the rod 4 in the axial direction (vertical direction) and the rotational position of the rod 4 in the direction around the axis.

  The encoder 17 may be an optical system using light reflection for detection or a magnetic system using magnetism. The encoder 17 may be an absolute method for measuring an absolute position or an increment method for measuring a relative position.

  Based on the detection result of the encoder 17, the fluid pressure actuator 1 </ b> A detects the pressure of the air K flowing into the first pressure chamber P <b> 1 via the first port 8 and the second pressure via the second port 9. A pressure adjusting unit 20 that adjusts the pressure of the air K flowing into the chamber P2 is provided.

  In the pressure adjusting unit 20, a common servo valve or a separate servo valve is provided in each of the first port 8 and the second port 9, and the pressure in the first pressure chamber P1 and the second pressure chamber P2 are set. Adjust the pressure. Thereby, the vertical position of the rod 4 can be controlled.

  Here, when the rod 4 slides in the vertical direction, the magnetic attractive force acting between the magnet of the rotor 15 and the coil of the stator 16 varies depending on the positional relationship of the rotor 15 with respect to the stator 16.

  Specifically, when the rotor 15 is located at a position facing the center of the stator 16, a magnetic attraction force that is equal in the vertical direction acts on the rotor 15. On the other hand, when the rotor 15 is above the position facing the center of the stator 16, a magnetic attractive force in a downward direction acts on the rotor 15, and the magnetic attractive force increases as the rotor 15 moves upward. Become. Conversely, when the rotor 15 is located below the position facing the center of the stator 16, a magnetic attractive force in the upward direction acts on the rotor 15, and the magnetic attractive force decreases as the rotor 15 moves downward. Become stronger. That is, the rotor 15 generates a certain holding force that tries to hold the rotor 15 at a position facing the center of the stator 16. Further, this holding force is proportional to the distance in the vertical direction from the center of the stator 16.

  In the fluid pressure actuator 1 </ b> A of the present embodiment, the pressure of the air K flowing into the first pressure chamber P <b> 1 via the first port 8 and the second port 9 so as to compensate for this holding force. The pressure is adjusted by correcting the pressure of the air K flowing into the second pressure chamber P2. Thereby, the vertical position of the rod 4 can be controlled with high accuracy.

  The fluid pressure actuator 1A having the above structure is used, for example, in a die bonding process or a mounting process of a semiconductor chip. Specifically, in the semiconductor manufacturing apparatus, the tool 4 for holding the semiconductor chip is slid (moved) within a range in which it can move in the vertical direction. Alternatively, the rod 4 is rotated in the necessary range in the direction around the axis. Thereby, the semiconductor chip can be mounted on a mounting surface such as a lead frame or a substrate.

  In the fluid pressure actuator 1A of the present embodiment, the piston 3 is supported by the first fluid bearing B1 so as to be slidable (movable) and rotatable in the vertical direction and the axial direction, and the rod 4 supports the second air bearing B2. Via the third air bearing B3, the shaft 11 is supported so as to slide (move) and rotate freely. Yes.

  In particular, in the fluid pressure actuator 1A of the present embodiment, the second porous bearing 10 is formed at the position where the second fluid bearing B2 is formed, and the second porous bearing B3 is formed at the position where the third fluid bearing B3 is formed. By providing the throttle 14, it is possible to increase the support rigidity of the rod 4 and the shaft 11 connected to the piston 3.

  Thereby, in the fluid pressure actuator 1A of the present embodiment, it is possible to perform high-precision load control and position control of the above-described semiconductor chip while sliding (moving) and rotating the rod 4 by non-contact driving. .

  Further, in the fluid pressure actuator 1A of the present embodiment, a mechanism for sliding (moving) the rod 4 and a mechanism for rotating the rod 4 can be integrated, so that a more compact design is performed. Is possible.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, it is possible to adopt a configuration of a fluid pressure actuator 1B as shown in FIG. FIG. 2 is a cross-sectional view showing the configuration of the fluid pressure actuator 1B. Moreover, in the following description, about the site | part equivalent to the said fluid pressure actuator 1A, while omitting description, the same code | symbol shall be attached | subjected in drawing.

  Specifically, in the fluid pressure actuator 1 </ b> B, as shown in FIG. 2, the total length of the stator 16 that constitutes the rotation drive unit 12 is longer than that of the rotor 15. The rest of the configuration is basically the same as that of the fluid pressure actuator 1A.

  In the case of this configuration, the total length of the fluid pressure actuator 1 </ b> B becomes long, but no holding force is generated to hold the rotor 15 at a position facing the center of the stator 16. Therefore, it is possible to control the position of the rod 4 in the vertical direction with high accuracy without performing pressure adjustment for compensating for such holding force.

  In the above embodiment, an air pressure cylinder using air K as the differential fluid is illustrated, but the present invention can be widely applied to fluid pressure actuators using fluids other than air K. is there. Further, the use of the fluid pressure actuator is not particularly limited, and can be applied to other than the semiconductor manufacturing apparatus described above.

  DESCRIPTION OF SYMBOLS 1A, 1B ... Fluid pressure actuator 2 ... Cylinder 3 ... Piston 4 ... Rod 5 ... Cylinder housing 6 ... Bore hole 7 ... 1st shaft hole 8 ... 1st port 9 ... 2nd port 10 ... 1st porous Diaphragm 11 ... Shaft 12 ... Rotation drive unit 13 ... Second shaft hole 14 ... Second porous aperture 15 ... Rotor 16 ... Stator 17 ... Encoder (position detection unit) 18 ... Scale 19 ... Case 20 ... Pressure adjustment unit K ... Air (fluid) P1 ... First pressure chamber P2 ... Second pressure chamber B1 ... First air bearing B2 ... Second air bearing B3 ... Third air bearing

Claims (7)

A cylinder,
A piston that moves inside the cylinder;
A rod that is connected to one end of the piston and that moves integrally with the piston in a state of protruding from a first shaft hole provided in the cylinder to the outside of the cylinder;
A shaft that is connected to the other end side of the piston and that moves integrally with the piston in a state of protruding from a second shaft hole provided in the cylinder to the outside of the cylinder;
A rotation drive unit including a rotor attached to the outer periphery of the shaft, and a stator surrounding the rotor;
A first fluid bearing is formed by the fluid flowing into the gap between the cylinder and the piston;
A second fluid bearing is formed by the fluid flowing into the gap between the first shaft hole and the rod;
A fluid pressure actuator, wherein a third fluid bearing is formed by a fluid flowing into a gap between the second shaft hole and the shaft.   Porous throttles are respectively provided at positions where the second fluid bearing is formed in the first shaft hole and positions where the third fluid bearing is formed in the second shaft hole. The fluid pressure actuator according to claim 1.   3. The fluid pressure actuator according to claim 1, wherein an overall length of the stator is longer than that of the rotor.   The fluid pressure actuator according to claim 1, wherein an overall length of the rotor is longer than that of the stator. A first port through which fluid flows into a first pressure chamber located on the shaft side across the piston in the cylinder;
A second port for allowing a fluid to flow into a second pressure chamber located on the rod side across the piston in the cylinder;
A position detector attached to the tip of the shaft;
Based on the detection result of the position detection unit, the pressure of the fluid flowing into the first pressure chamber through the first port and the second pressure chamber through the second port. The fluid pressure actuator according to any one of claims 1 to 4, further comprising a pressure adjusting unit that adjusts a pressure of the fluid.   The pressure adjusting unit takes into account fluctuations in the magnetic attractive force acting between the rotor and the stator, and the pressure of the fluid flowing into the first pressure chamber through the first port; The fluid pressure actuator according to claim 5, wherein the pressure of the fluid flowing into the second pressure chamber through the second port is adjusted.   The fluid pressure actuator according to claim 1, wherein the fluid is air.

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