JP4547658B2 - Magnetic screw coupling type rotary actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary actuator that converts a linear reciprocating motion of a piston into a rotational swing motion of an output shaft and takes it out.
[0002]
[Prior art]
In recent years, along with the development of various electronic devices and information transmission devices, semiconductor devices used for them have been miniaturized and highly integrated. In many cases, the production lines include various devices used there. On the other hand, very strict cleanliness is required. For example, the same applies to pneumatic equipment such as a rotary actuator used for driving the equipment and transporting the wafer.
[0003]
Currently, when a vane-type rotary actuator is used in a clean environment such as a vacuum chamber or a clean room, the measures shown in Fig. 4 or Fig. 5 are generally taken so that the dust generated from this actuator does not become a source of contamination. ing. 4 is provided with double seal members 4, 4 on both sides of the bearing portions 3, 3 at both ends of the output shaft 2 to which the vane 1 is attached, and between the inner and outer seal members 4, 4, Dust discharge ports 5 and 5 are provided for releasing generated dust. On the other hand, what is shown in FIG. 5 is that the above-mentioned ports 5 and 5 are connected to a suction pump without providing the double structure sealing member, and dust generated inside the actuator is forcibly sucked using vacuum pressure. Like to do.
[0004]
However, in this type of vane type rotary actuator, since the output shaft 2 continuously extends from the pressure chamber 6 where the vane 1 operates to the outside of the casing 7, the above-described dust-proof measures are taken. Even so, it is practically difficult to prevent the dust generation from the inside of the pressure 6 chamber and the sliding portion between the casing 7 and the output shaft 2 from leaking completely. In addition, even if the seal is doubled, it is difficult to completely stop air leakage from the sliding part. Therefore, when the actuator is used in a vacuum chamber, the degree of vacuum is reduced due to slight leakage. Problems such as difficulty in rising and contamination of the environment due to dust leaking along with the leakage are likely to occur.
[0005]
[Problems to be solved by the invention]
In view of the structural problems of the vane-type rotary actuator, the technical problem of the present invention is that the output shaft is rotated and oscillated by means other than the vane. The purpose is to provide a rotary actuator with improved performance.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, according to the present invention, a casing having a small-diameter inner cylinder portion and a large-diameter outer cylinder portion made of a non-magnetic material are provided between an inner and an outer double portion, and formed between the two cylinder portions. An annular piston chamber, an annular piston which is disposed in the piston chamber so as to be slidable in the axial direction in a state where rotation is prevented, and moves forward and backward by the action of air pressure, a central hole of the inner cylinder portion An output shaft that is rotatable while being prevented from moving in the axial direction and is housed in a non-sliding manner with respect to the casing, pressure chambers formed on both sides of the piston in the piston chamber, and pressure in each pressure chamber A port for supplying air, a female magnetic screw formed by alternately and spirally arranging magnetic pole bands of N and S poles on the inner peripheral surface of the piston, and N poles on the outer peripheral surface of the output shaft as well as Is formed by placing and spirally alternately poles of the magnetic pole zone, it has a magnetic coupling males magnetic screw to and from the female magnetic thread of the piston within the peripheral surface through the inner cylinder portion, the casing A first member having the inner cylinder part and a flange-shaped main body part projecting from one end of the inner cylinder part in the outer circumferential direction; and the outer member extending from the one end of the outer cylinder part and the outer cylinder part in the inner circumferential direction. And a second member having a flange-shaped main body portion, and the inner cylinder portion of the first member is coaxially fitted into the outer cylinder portion of the second member, and the tip of each cylinder portion is connected to the other side. A magnetic screw-coupled rotary actuator is provided that is assembled integrally by hermetically coupling to the main body of the member .
[0007]
In the rotary actuator having the above configuration, when pressure air is supplied to the pressure chamber and the piston is moved forward and backward, the output shaft magnetically coupled to the piston is oscillated and rotated according to the inclination angle of the magnetic screw. Oscillating rotation is taken out as output. At this time, the pressure chamber and the piston are shut off from the external environment, and the pressure chamber and the piston and the output shaft are isolated from each other. There is no problem that dust generated by sliding leaks to the outside.
[0008]
According to a specific embodiment of the present invention, the means for preventing rotation of the piston is a pin provided in the piston chamber, and the pin penetrates the piston in the axial direction.
[0010]
In the present invention, both ends of the output shaft are rotatably supported by bearings, a bearing that supports one end of the output shaft is attached to the first member, and a bearing that supports the other end is the first. It is attached to two members.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show a preferred typical embodiment of a magnetic screw-coupled rotary actuator according to the present invention. This actuator includes a casing 10 made of a nonmagnetic material. The casing 10 is provided with a small-diameter inner cylinder portion 11 and a large-diameter outer cylinder portion 12 that are coaxially positioned inside and outside, and is completely isolated from the external environment between the cylinder portions 11 and 12. An annular piston chamber 13 is formed, and the annular piston 14 is slidable in the axial direction in the piston chamber 13 while being prevented from rotating around its axis by the rotation preventing means 15. It is arranged like this. Further, first and second pressure chambers 18 a and 18 b are formed on both sides of the piston 14, respectively, and these pressure chambers 18 a and 18 b are connected to first and second ports 19 a and 19 b formed in the casing 10. 19b is connected to each.
[0012]
A cylindrical output shaft 16 is supported in the inner hole 21 of the inner cylinder portion 11 by bearings 22a and 22b at both ends thereof, so that the axial line is prevented from moving in the axial direction. It is accommodated so that it can rotate freely.
[0013]
Further, on the inner peripheral surface of the piston 14, a magnetic pole band 23a formed by magnetizing an N pole magnetic pole in a band shape and a magnetic pole band 23b formed by magnetizing an S pole magnetic pole in a band shape alternately and A female magnetic screw 23 is formed by arranging it in a spiral shape. On the other hand, on the outer peripheral surface of the output shaft 16, a magnetic pole band 24a is formed by similarly magnetizing N-pole and S-pole magnetic poles in the form of bands. , 24b are alternately and spirally arranged to form a male magnetic screw 24 having the same inclination direction and the same inclination angle as the female magnetic screw 23, and the female magnetic screw 23 and the male magnetic screw 24 The piston 14 and the output shaft 16 are magnetically coupled to each other.
[0014]
The casing 10 is assembled by coupling the first member 10A and the second member 10B to each other. Of these, the first member 10A has the inner cylinder portion 11 having a small diameter cylindrical shape, and a main body portion 26 having a rectangular flange shape projecting from one end of the inner cylinder portion 11 to the outside. The center hole 21 is provided so as to pass through the central portion of the cylinder portion 11 and the main body portion 26. One second member 10B includes the outer cylinder portion 12 having a prismatic shape, and a flange-shaped main body portion 28 projecting inward from one end of the outer cylinder portion 12, and the outer cylinder portion. 12 is formed with a circular cylinder hole having a diameter larger than that of the inner cylinder part 11 and a central hole 29 into which the inner cylinder part 11 is fitted at the center part of the main body part 28. The inner cylinder portion 11 of the first member 10A is coaxially fitted into the cylinder hole of the two member 10B, and the ends of the cylinder portions 11 and 12 are connected to the main body portions 28 and 26 of the mating members 10B and 10A. Are integrally assembled by being hermetically coupled to each other through seal members 31 and 32. One bearing 22a that supports one end of the output shaft 16 is attached to the center hole 21 of the first member 10A, and the other bearing 22b that supports the other end of the output shaft 16 to the center hole 29 of the second member 10B. Is attached.
[0015]
In the figure, 33 is a member for fixing the bearing 22b, and 34 is a bracket for connecting a driven member to the output shaft 16.
[0016]
The rotation preventing means 15 for preventing the rotation of the piston 14 includes a pin 15a provided in the axial direction in the piston chamber 13, and the pin 15a can slide the piston 14 in the axial direction. It penetrates to become. In the figure, 35 is a guide for guiding the sliding between the piston 14 and the pin 15a, and 36 and 37 are seal members.
[0017]
In the rotary actuator having the above-described configuration, when pressure air is alternately supplied from the two ports 19a and 19b to the first pressure chamber 18a and the second pressure chamber 18b, the piston 14 restricts rotation around the axis by the pin 15a. In this state, the piston chamber 13 moves back and forth in the axial direction along the pin 15a. At this time, since the piston 14 and the output shaft 16 are magnetically coupled to each other by the magnetic screws 23 and 24, the output shaft 16 swings and rotates according to the inclination angle of the magnetic screws 23 and 24. Oscillating rotation is taken out as output.
[0018]
Thus, in the actuator, the piston 14 that slides in the axial direction in the piston chamber 13 and the output shaft 16 that is rotatable around the axis in the center hole 21 of the inner cylinder portion 11 are connected to the magnetic screws 23 and 24. By being coupled to each other by the magnetic force, the linear reciprocating motion of the piston 14 can be converted into the rotational swing motion of the output shaft 16 and extracted. Further, the pressure chambers 18a and 18b and the piston 14 are cut off from the external environment without having an output shaft extending outside from the pressure chamber through a sliding portion like a conventional vane actuator, and these pressures Since the chambers 18a and 18b and the piston 14 and the output shaft 16 are isolated from each other, the air in the pressure chambers 18a and 18b leaks through a sliding portion between the output shaft 16 and the casing 10, or the pressure Dust generated inside the chambers 18a and 18b does not leak to the outside together with the leak air, and the dust resistance is excellent.
[0019]
Seal members 31 and 32 are provided between the first member 10A and the second member 10B, and the air tightness of the pressure chambers 18a and 18b is maintained by the seal members 31 and 32. The seal members 31 and 32 are different from the seal member of the vane type actuator that is interposed between the sliding portion of the rotating output shaft and the casing and rubs against these members. Since it is provided in a stationary state between 10A and the second member 10B and does not rub against both members, its sealing accuracy is high and dust generation due to sliding does not occur.
[0020]
Further, as described above, the piston 14 and the output shaft 16 are coupled to each other in a non-contact state by the magnetic screws 23 and 24, and the linear reciprocating motion of the piston 14 is converted into the rotational swing motion of the output shaft 16 and taken out. Therefore, the sliding part accompanying rotation between the output shaft 16 and the casing 10 can be eliminated, and generation of dust due to friction can be reliably prevented.
In the illustrated embodiment, the outer cylinder portion 12 of the second member 10B has a rectangular cross section, but it goes without saying that it may be cylindrical.
[0021]
【The invention's effect】
As described in detail above, the rotary actuator according to the present invention has a piston that slides in the axial direction in the pressure chamber and an output shaft that is rotatable around the axis, and is coupled to each other by the magnetic force of the magnetic screw. The linear reciprocating motion of the piston can be converted into the rotational swing motion of the output shaft and taken out.
Further, the rotary actuator of the present invention does not have an output shaft that extends to the outside through a sliding portion from a pressure chamber like a conventional vane actuator, and the pressure chamber and the piston are shut off from the external environment, Since the pressure chamber, the piston, and the output shaft are isolated from each other, there is no problem that air in the pressure chamber leaks to the outside, and dust generated by sliding of the piston leaks to the outside.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a rotary actuator according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
3 is a cross-sectional view showing a state where an output shaft is removed from FIG. 1. FIG.
FIG. 4 is a cross-sectional view showing an example of a conventional vane type rotary actuator.
FIG. 5 is a cross-sectional view showing another example of a conventional vane type rotary actuator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Casing 10A 1st member 10B 2nd member 11 Inner cylinder part 12 Outer cylinder part 13 Piston chamber 14 Piston 15 Anti-rotation means 15a Pin 16 Output shaft 18a, 18b Pressure chamber 19a, 19b Port 21 Center hole 22a, 22b Bearing 23 Female Side magnetic screws 23a, 23b Magnetic pole band 24 Male magnetic screws 24a, 24b Magnetic pole bands 26, 28 Main body

Claims (3)

A casing having a small-diameter inner cylinder portion and a large-diameter outer cylinder portion made of a non-magnetic material, both inside and outside,
An annular piston chamber formed between the cylinder portions,
An annular piston disposed in the piston chamber so as to be slidable in the axial direction in a state in which rotation is prevented;
An output shaft which is rotatable in a state where movement in the axial direction is prevented in the center hole of the inner cylinder part and is housed in a non-sliding state with the casing;
Pressure chambers formed on both sides of the piston in the piston chamber;
A port for supplying pressure air to each pressure chamber;
A female magnetic screw formed by alternately and spirally arranging N-pole and S-pole magnetic pole bands on the inner peripheral surface of the piston;
Formed by alternately and spirally arranging N-pole and S-pole magnetic pole bands on the outer peripheral surface of the output shaft, and magnetically coupled to the female magnetic screw on the inner peripheral surface of the piston via the inner cylinder portion A male magnetic screw ,
The casing has a first member having the inner cylinder part and a flange-shaped main body part projecting from one end of the inner cylinder part in the outer circumferential direction, and an inner circumferential direction from the outer cylinder part and one end of the outer cylinder part. And a second member having a flange-shaped main body portion projecting from the inner member. The inner cylinder portion of the first member is coaxially fitted into the outer cylinder portion of the second member, and the tip of each cylinder portion is opposed to the other member. A magnetic screw-coupled rotary actuator, wherein the magnetic screw-coupled rotary actuator is integrally assembled by airtightly coupling to a main body of a side member .   The rotary actuator according to claim 1, wherein the means for preventing rotation of the piston is a pin provided in the piston chamber, and the pin penetrates the piston in the axial direction. Both ends of the output shaft are rotatably supported by bearings, a bearing that supports one end of the output shaft is attached to the first member, and a bearing that supports the other end is attached to the second member. rotary actuator according to claim 1 or 2, characterized in that is.

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