JP2011119301A - Actuator for vacuum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator for vacuum, capable of simplifying and miniaturizing a configuration, improving driving accuracy and facilitating the core shift adjustment of a shaft. <P>SOLUTION: The actuator for the vacuum includes an output shaft 3 which is arranged through a vacuum container 11 and includes a magnetic material, a power generation unit 2 which rotationally drives the output shaft 3 from the outside of the vacuum container 11, an attachment unit 4 which is attached to the outer side of the vacuum container 11, supports the power generation unit 2 and includes a non-magnetic material, a magnetic fluid seal 5 which is arranged between the output shaft 3 and the attachment unit 4 and partitions the inside of the vacuum container 11 and the power generation unit 2, and a bearing 6 which is arranged near the magnetic fluid seal 5 and rotatably supports the output shaft 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vacuum actuator that transmits a rotational driving force into a vacuum vessel such as a semiconductor manufacturing apparatus.

In general, when a rotational driving force is transmitted to a device arranged inside a vacuum vessel, a configuration is adopted in which a rotating shaft extending from an electric motor arranged outside the vacuum vessel is extended to the above device.
In a magnetic disk or the like, a magnetic fluid seal portion is used for the purpose of preventing dust such as lubricant fine particles from scattering outside the motor during rotation of the motor (see, for example, Patent Document 1).

For example, when a linear motion stage arranged inside a vacuum vessel is moved, the rotational driving force transmitted by the rotation shaft is converted into a force for driving the stage by a ball screw.
In that case, for example, on the outside of the vacuum vessel, the output shaft (rotary shaft) of the electric motor or the output shaft of the speed reducer is connected to the rotational shaft of the magnetic fluid seal portion using a coupling. On the other hand, inside the vacuum vessel, the rotating shaft of the magnetic fluid seal portion is connected to the input shaft of the ball screw using a coupling.

JP-A-11-103553

  However, the above-described configuration requires a motor support bracket for attaching the electric motor to the vacuum vessel, and a coupling, which increases the number of parts, resulting in a problem that the vacuum actuator is expensive.

  There is a problem that the structure of the vacuum actuator becomes longer in the axial direction of the rotating shaft, and the space required for installation becomes wider. In other words, when the vacuum actuator is installed in the vacuum vessel, there is a problem that the vacuum actuator interferes with other devices and the degree of freedom in design is reduced.

  Furthermore, since the length of the rotating shaft of an electric motor or the like becomes longer and the rigidity of the shaft becomes lower, there is a problem that the controllability by the vacuum actuator is lowered. That is, there is a problem that the rotational phase of the electric motor is not accurately transmitted to the linear motion stage or the like due to the deflection in the torsional direction generated on the rotary shaft or the like, and the moving distance of the stage on the linear motion stage cannot be accurately controlled.

  On the other hand, adjustment of misalignment of the shaft between the output shaft of the electric motor or the output shaft of the speed reducer and the input shaft of the magnetic fluid seal and between the output shaft of the magnetic fluid seal and the input shaft of the ball screw is performed. There is a need to do. In other words, the shaft misalignment adjustment needs to be performed in two stages, and there is a problem that the adjustment takes time.

  The present invention has been made to solve the above-described problems, and can simplify and reduce the size of the configuration, increase the driving accuracy, and facilitate adjustment of the shaft misalignment. An object of the present invention is to provide a vacuum actuator.

In order to achieve the above object, the present invention provides the following means.
The vacuum actuator according to the present invention includes an output shaft made of a magnetic material, penetrating the vacuum vessel, a power generation unit that rotationally drives the output shaft from the outside of the vacuum vessel, and an outside of the vacuum vessel It is attached to the side surface and supports the power generation unit, and is disposed between the mounting unit made of a nonmagnetic material, the output shaft and the mounting unit, and between the inside of the vacuum vessel and the power generation unit. A magnetic fluid seal for partitioning and a bearing portion disposed in the vicinity of the magnetic fluid seal and rotatably supporting the output shaft are provided.

  According to the present invention, since the output shaft for transmitting the rotational driving force from the power generation unit is directly guided to the inside of the vacuum vessel, the driven device disposed inside the vacuum vessel through only one coupling. Rotational driving force can be supplied to the input shaft. That is, the number of parts constituting the vacuum actuator can be reduced as compared with the conventional method in which the rotational driving force is supplied via the rotational shafts of at least two couplings and the magnetic fluid seal portion.

On the other hand, the vacuum actuator can be reduced in size by reducing the number of parts.
Furthermore, the moment of inertia related to rotation is reduced by reducing the number of rotating parts. Therefore, the driving accuracy of the vacuum actuator can be increased.

  Only the output shaft transmits the rotational driving force inside the vacuum actuator, and no coupling is provided inside the vacuum actuator. Therefore, the shaft misalignment adjustment may be performed only between the output shaft of the vacuum actuator and the input shaft of the driven device. That is, the shaft misalignment can be easily adjusted.

  Furthermore, since only the output shaft transmits the rotational driving force in the vacuum actuator, the torsional rigidity in the vacuum actuator is increased, and the driving accuracy can be increased. For example, the vacuum actuator of the present invention has a shorter shaft length for transmitting the rotational driving force than the conventional method for transmitting the rotational driving force using the output shaft and the rotating shaft of the magnetic fluid seal portion. In other words, the torsional rigidity of the shaft related to transmission of the rotational driving force is increased. Therefore, the difference between the rotation angle in the power generation unit of the vacuum actuator and the rotation angle in the input shaft of the driven device is reduced, and the driven device can be accurately driven and controlled.

  In the above invention, it is desirable that a speed change unit for increasing or decreasing the torque transmitted from the power generation unit to the output shaft is provided between the power generation unit and the magnetic fluid seal.

  According to the present invention, the rotational speed and torque related to the rotational driving force generated in the power generation unit can be converted into the desired rotational speed and torque in the transmission unit and transmitted to the driven device. Therefore, the range of torque transmitted to the driven device can be easily expanded as compared with the method of changing the rotational speed and torque related to the rotational driving force transmitted to the driven device by changing only the power generation unit. .

  In the above invention, at least one of the bearing portions is disposed between the magnetic fluid seal and the power generation portion, and at least one is disposed between the magnetic fluid seal and the vacuum vessel. desirable.

According to the present invention, since the bearing portion is disposed across the magnetic fluid seal, the posture of the output shaft in the region where the magnetic fluid seal is disposed is stabilized. Therefore, it is possible to suppress a decrease in sealing performance in the magnetic fluid seal.
In particular, if a plurality of bearing portions are disposed between the magnetic fluid seal and the vacuum vessel, the posture of the output shaft in the region where the magnetic fluid seal is disposed is further stabilized.

  In the said invention, it is desirable to provide the seal part which airtightly partitions between the said power generation part, the said bearing part, and the said magnetic fluid seal.

According to the present invention, it is possible to prevent liquid from entering the magnetic fluid seal from the power generation unit. Therefore, deterioration of the sealing performance of the magnetic fluid seal can be prevented.
For example, when performing a leak check of a vacuum vessel, a highly volatile liquid such as alcohol is applied to the outer surface of the vacuum vessel. At this time, liquid may also be applied to the power generation part of the vacuum actuator. If the seal part is not provided, the liquid may enter the inside of the power generation part, enter the magnetic fluid seal, and destroy the seal. However, the provision of the seal portion prevents liquid from entering the magnetic fluid seal.

  According to the vacuum actuator of the present invention, the output shaft disposed through the vacuum vessel is formed of a magnetic material, and the magnetic fluid seal is disposed between the mounting portion made of a nonmagnetic material and the output shaft. As a result, the vacuum actuator can be simplified and miniaturized, the driving accuracy can be increased, and the shaft misalignment can be easily adjusted.

It is a schematic diagram explaining the structure of the vacuum actuator which concerns on the 1st Embodiment of this invention. It is the elements on larger scale explaining the structure of the magnetic fluid seal | sticker of FIG. It is a schematic diagram explaining the structure of the actuator for vacuums concerning the 2nd Embodiment of this invention. FIG. 4 is a partially enlarged view for explaining a configuration of an attachment portion in FIG. 3. It is a schematic diagram explaining the structure of the actuator for vacuums concerning the 3rd Embodiment of this invention. It is the elements on larger scale explaining the structure regarding the bearing part of FIG. It is a schematic diagram explaining the structure of the actuator for vacuums concerning the 4th Embodiment of this invention. It is the elements on larger scale explaining the structure of the bearing holding | suppressing part of FIG.

[First Embodiment]
The vacuum actuator according to the first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic diagram illustrating the configuration of the vacuum actuator according to the present embodiment.
In the present embodiment, the vacuum actuator 1 according to the present invention will be described by applying it to an actuator that supplies a rotational driving force to a driven device such as a linear motion stage disposed inside a vacuum vessel 11. More specifically, description will be made by applying to a device that supplies a rotational driving force to a driven device arranged inside a vacuum vessel constituting a plasma CVD apparatus used for manufacturing a solar cell or the like.

  As shown in FIG. 1, the vacuum actuator 1 is mainly provided with a motor (power generation part) 2, an output shaft 3, a mounting part 4, a magnetic fluid seal 5, and a bearing part 6. Yes.

The motor 2 generates a rotational driving force and drives the output shaft 3 to rotate. The motor 2 is disposed outside the vacuum vessel 11 and is attached to the vacuum vessel 11 via the attachment portion 4.
A bearing portion 6 is disposed inside the motor 2 of the present embodiment.
As the motor 2, a motor having a known configuration can be used and is not particularly limited.

The output shaft 3 transmits the rotational driving force supplied from the motor 2 to the input shaft 12 of the driven device. The output shaft 3 is a columnar member formed from a magnetic material, for example, a material such as carbon steel for mechanical structures or martensitic stainless steel.
The output shaft 3 is rotatably supported by the bearing portion 6. Further, a magnetic fluid seal 5 is disposed around the output shaft 3.
A coupling 13 is disposed between the output shaft 3 and the input shaft 12, and is connected to the input shaft 12 of the driven device via the coupling 13 so that the rotational driving force can be transmitted.

  The attachment portion 4 attaches the motor 2 to the vacuum vessel 11 and also serves as a seal portion that keeps the inside of the vacuum vessel 11 in a vacuum state. The attachment portion 4 is a member formed on a disc made of a non-magnetic material, for example, a material such as austenitic stainless steel, aluminum alloy, or ceramic.

A through-hole through which the output shaft 3 is inserted is formed at the center of the mounting portion 4, and a collar portion 41 and a retaining ring 42 that are used when the magnetic fluid seal 5 is disposed are provided in the through-hole. Yes.
The flange 41 holds the magnetic fluid seal 5 with the retaining ring 42.
The flange 41 protrudes radially inward, that is, toward the output shaft 3 at the end of the through hole on the motor 2 side.
The retaining ring 42 is a ring plate-like member fitted into the inner peripheral surface of the above-described through hole, and can be elastically deformed in the radial direction. The retaining ring 42 is inserted into the inner peripheral surface of the through hole after the magnetic fluid seal 5 is inserted into the above through hole and pressed against the flange 41.

On the other hand, a groove surrounding the output shaft 3 is formed on the surface of the mounting portion 4 facing the vacuum container 11, and a vacuum seal 43 such as an O-ring is disposed in the groove.
The vacuum seal 43 is a seal member formed from an elastic material such as rubber, and maintains the vacuum state inside the vacuum vessel 11.

FIG. 2 is a partially enlarged view illustrating the configuration of the magnetic fluid seal of FIG.
The magnetic fluid seal 5 keeps the vacuum degree inside by blocking the vacuum vessel 11 from the atmosphere.
As shown in FIG. 2, the magnetic fluid seal 5 is mainly provided with a magnet 51, a seal plate 52, and a magnetic fluid 53.

  The magnet 51 is a ring-shaped member having a square cross section, and is formed from a material that forms a magnetic field, such as a permanent magnet. A seal plate 52 is disposed on the surface of the magnet 51 on the motor 2 side and the surface on the vacuum vessel 11 side. The output shaft 3 is inserted through the hole of the magnet 51.

  The seal plate 52 is a ring plate-like member formed from a material having magnetism, for example, a material such as mechanical structural carbon steel or martensitic stainless steel. The seal plate 52 is disposed with the magnet 51 in between, and the magnet 51 is disposed so that the generated magnetic lines of force enter the seal plate 52.

  The output shaft 3 is inserted into the hole of the seal plate 52. Further, a magnetic fluid 53 is disposed in the gap between the seal plate 52 and the output shaft 3. In the present embodiment, the magnetic fluid 53 is applied to only one of the pair of seal plates 52. However, the magnetic fluid 53 may be disposed on both, and in particular, It is not limited.

The magnetic fluid 53 is disposed between the output shaft 3 and the seal plate 52, and keeps the vacuum vessel 11 from the atmosphere side and maintains the degree of vacuum inside.
The shape of the magnetic fluid 53 is controlled according to the magnetic field formed between the magnet 51, the pair of seal plates 52, and the output shaft 3. More specifically, the form changes according to the arrangement of magnetic lines of force formed between the seal plate 52 and the output shaft 3. The space between the outer periphery of the seal plate 52 and the mounting portion 4 is kept airtight by a sealant or the like.
In addition, as the magnetic fluid 53, the thing of a well-known composition can be used and it does not specifically limit.

The bearing portion 6 supports the output shaft 3 in a rotatable manner, and is, for example, a deep groove ball bearing.
In the present embodiment, the bearing portion 6 is disposed inside the motor 2 and closer to the motor 2 than the magnetic fluid seal 5.
In addition, as a bearing part 6, a well-known bearing can be used and it does not specifically limit.

Next, the supply of the rotational driving force in the vacuum actuator 1 having the above configuration will be described with reference to FIG.
The rotational driving force generated by the motor 2 is transmitted to the output shaft 3, and the output shaft 3 is rotationally driven. The rotational driving force transmitted to the output shaft 3 is transmitted to the coupling 13 disposed in the vacuum vessel 11 and is transmitted to the input shaft 12 of the non-driven device through the coupling 13. The non-driving device is driven based on the rotational driving force transmitted to the input shaft 12.

  In the magnetic fluid seal 5, as shown in FIG. 2, the magnetic fluid 53 forms a liquid seal structure in response to a magnetic field formed between the seal plate 52 and the rotating output shaft 3 by the magnet 51. . Therefore, the magnetic fluid seal 5 can maintain the vacuum degree of the vacuum vessel 11 without hindering the rotation of the output shaft 3.

  According to the above configuration, since the output shaft 3 that transmits the rotational driving force from the motor 2 is directly guided to the inside of the vacuum vessel 11, the output shaft 3 is arranged inside the vacuum vessel 11 through only one coupling. A rotational driving force can be supplied to the input shaft 12 of the driven device. That is, the number of parts constituting the vacuum actuator 1 can be reduced and the vacuum can be inexpensively compared with the conventional method of supplying the rotational driving force via the rotational shaft of at least two couplings and the magnetic fluid seal portion. A rotational driving force can be introduced into the container 11.

On the other hand, by reducing the number of parts, the vacuum actuator 1 can be reduced in size, and interference with other devices arranged outside the vacuum vessel 11 can be easily avoided. In other words, the structure of the vacuum actuator 1 becomes compact and the degree of freedom in design increases.
Furthermore, the moment of inertia related to rotation is reduced by reducing the number of rotating parts. Therefore, the driving accuracy of the vacuum actuator 1 can be increased.

  Only the output shaft 3 transmits the rotational driving force inside the vacuum actuator 1, and no coupling is provided inside the vacuum actuator 1. Therefore, the shaft misalignment adjustment may be performed only between the output shaft 3 of the vacuum actuator 1 and the input shaft 12 of the driven device. That is, the shaft misalignment can be easily adjusted.

  Furthermore, since only the output shaft 3 transmits the rotational driving force in the vacuum actuator 1, the torsional rigidity in the vacuum actuator 1 is increased, and the driving accuracy can be increased. For example, the vacuum actuator 1 according to the present embodiment has a shaft length that transmits the rotational driving force as compared with the conventional method of transmitting the rotational driving force using the output shaft 3 and the rotating shaft of the magnetic fluid seal portion. Is short. In other words, the torsional rigidity of the shaft related to transmission of the rotational driving force is increased. Therefore, the difference between the rotation angle of the motor 2 of the vacuum actuator 1 and the rotation angle of the input shaft 12 of the driven device is reduced, and the driven device can be accurately driven and controlled.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. 3 and FIG.
The basic configuration of the vacuum actuator of this embodiment is the same as that of the first embodiment, but is mainly different from the first embodiment in that a planetary reduction gear unit is provided. Therefore, in this embodiment, the periphery of the planetary speed reducer unit will be described with reference to FIGS. 3 and 4 and description of other components and the like will be omitted.
FIG. 3 is a schematic diagram illustrating the configuration of the vacuum actuator according to the present embodiment. FIG. 4 is a partially enlarged view illustrating the configuration of the attachment portion in FIG.
In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 3, the vacuum actuator 101 includes a motor 2, an output shaft 103, a mounting portion 104, a magnetic fluid seal 5, a bearing portion 106, and a planetary speed reducer portion (transmission portion) 107. It is mainly provided.

  As shown in FIGS. 3 and 4, the output shaft 103 transmits the rotational driving force whose torque is increased by the planetary reduction gear unit 107 to the input shaft 12 of the driven device. The output shaft 103 is a columnar member made of a magnetic material, for example, a carbon steel for machine structure or a martensitic stainless steel, and the end on the planetary reduction gear unit 107 side has a planetary reduction gear. It is formed in a disk shape or an arm shape to which the rotational driving force is transmitted from the portion 107.

  Further, the output shaft 103 is provided with a retaining ring 142 that determines a relative position between the magnetic fluid seal 5 and the bearing portion 106, in other words, a relative position between the mounting portion 104 and the output shaft 103. The retaining ring 142 is a member on a ring plate that is fitted into the outer peripheral surface of the output shaft 103 and is elastically deformable in the radial direction. The retaining ring 142 is inserted into the output shaft 103 from the vacuum vessel 11 side after the bearing portion 106 disposed in the mounting portion 104 has inserted the output shaft 103 through the magnetic fluid seal 5.

  The attachment part 104 functions as a seal part for attaching the motor 2 to the vacuum vessel 11 and keeping the inside of the vacuum vessel 11 in a vacuum state. The mounting portion 104 is made of a nonmagnetic material, for example, a material such as austenitic stainless steel, aluminum alloy, or ceramics.

The attachment portion 104 is formed in a cylindrical shape, and a flange portion extending radially outward is formed at an end portion on the vacuum vessel 11 side. Inside the mounting portion 104, a bearing portion 106, a collar 151, a magnetic fluid seal 5, a collar 151, a bearing portion 106, and a planetary speed reducer portion 107 are arranged from the vacuum vessel 11 toward the motor 2.
Further, on the inner peripheral surface of the mounting portion 104, a flange portion 141, a female screw portion 162 that is screwed with the bearing pressing portion 161, and an internal tooth 174 of the planetary speed reducer portion 107 are formed.

  The flange 141 protrudes inward in the radial direction at the end of the mounting portion 104 on the vacuum container 11 side. The flange portion 141 is in contact with the bearing portion 106 on the vacuum vessel 11 side, and determines the arrangement position of the bearing portion 106 and the magnetic fluid seal 5 with respect to the attachment portion 104.

The bearing unit 106 rotatably supports the output shaft 103 and is, for example, a deep groove ball bearing.
In the present embodiment, one bearing portion 106 is disposed inside the attachment portion 104, one on the vacuum container 11 side and one on the motor 2 side of the magnetic fluid seal 5. In other words, the two bearing portions 106 are arranged so as to sandwich the magnetic fluid seal 5 therebetween.

A collar 151 is disposed between the bearing portion 106 and the magnetic fluid seal 5.
The collar 151 is a member formed in a cylindrical shape, and is formed of a nonmagnetic material like the attachment portion 104. By using the collar 151, a predetermined interval is formed between the bearing portion 106 and the magnetic fluid seal 5.

The bearing portion 106 disposed on the motor 2 side is pressed against the flange 141 side by the bearing pressing portion 161. The bearing holding portion 161 holds the bearing portion 106 with the flange portion 141. The bearing holding portion 161 is a member formed on the ring plate, and a male screw that meshes with the female screw portion 162 formed on the mounting portion 104 is formed on the outer peripheral surface.
The bearing portion 106, the collar 151, and the magnetic fluid seal 5 are inserted into the mounting portion 104, and the bearing holding portion 161 is screwed into the female screw portion 162. Attached to.

The planetary speed reducer unit 107 increases the torque related to the rotational driving force generated by the motor 2 and decreases the rotational speed. The planetary speed reducer unit 107 is disposed between the motor 2 and the output shaft 103 and is disposed inside the attachment unit 104.
The planetary reduction gear unit 107 is mainly provided with a sun gear 171, a planetary gear 172, a pin 173, and an internal tooth 174.

The sun gear 171 is a gear that is attached to the rotation shaft 121 of the motor 2 and is rotationally driven together with the rotation shaft 121. A tooth surface that meshes with the planetary gear 172 is formed on the outer peripheral surface of the sun gear 171.
The planetary gear 172 is a gear that is attached to the output shaft 103 via the pin 173 and is disposed between the sun gear 171 and the attachment portion 104. The planetary gear 172 meshes with the tooth surface of the sun gear and also meshes with the internal teeth 174 formed on the inner peripheral surface of the mounting portion 104.
Further, the planetary gear 172 is configured to be rotatable (rotatable) about the pin 173 and is also configured to be rotatable (revolved) about the output shaft 103.

The pin 173 attaches the planetary gear 172 to the output shaft 103, and also supports the planetary gear 172 so that it can rotate.
The internal teeth 174 are tooth surfaces formed in a circumferential shape on the inner peripheral surface of the mounting portion 104 and mesh with the planetary gear 172.

  In addition, as a structure of the planetary speed reducer part 107, a well-known structure can be used and it does not specifically limit.

Next, the supply of the rotational driving force in the vacuum actuator 101 having the above configuration will be described with reference to FIG.
The rotational driving force generated by the motor 2 is transmitted to the planetary speed reducer unit 107. In the planetary reduction gear unit 107, the rotation of the sun gear 171 causes the planetary gear 172 to revolve around the sun gear 171 while rotating. The revolution of the planetary gear 172 is transmitted to the output shaft 103 via the pin 173, and the output shaft 103 is rotationally driven. The rotational driving force transmitted to the output shaft 103 is transmitted to the coupling 13 disposed in the vacuum vessel 11, and is transmitted to the input shaft 12 of the non-driven device via the coupling 13. The non-driving device is driven based on the rotational driving force transmitted to the input shaft 12.

  According to said structure, the rotational speed and torque regarding the rotational driving force which generate | occur | produced in the motor 2 can be converted into a desired rotational speed and torque in the planetary reduction gear part 107, and can be transmitted to a to-be-driven device. Therefore, the range of the torque transmitted to the driven device can be easily expanded as compared with the method of changing the rotational speed and torque related to the rotational driving force transmitted to the driven device by changing only the motor 2.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the vacuum actuator of this embodiment is the same as that of the second embodiment, but is different from the second embodiment in that there is no planetary speed reducer portion and the configuration related to the bearing portion. Therefore, in this embodiment, only the structure regarding a bearing part is demonstrated using FIG. 5 and FIG. 6, and description of other components is abbreviate | omitted.
FIG. 5 is a schematic diagram illustrating the configuration of the vacuum actuator according to the present embodiment. FIG. 6 is a partially enlarged view illustrating a configuration related to the bearing portion of FIG.
In addition, the same code | symbol is attached | subjected to the component same as 2nd Embodiment, and the description is abbreviate | omitted.

  As shown in FIGS. 5 and 6, the vacuum actuator 201 is mainly provided with a motor 2, an output shaft 203, a mounting portion 204, a magnetic fluid seal 5, and a bearing portion 206.

  As shown in FIGS. 5 and 6, the output shaft 203 transmits the rotational driving force generated by the motor 2 to the input shaft 12 of the driven device. The output shaft 103 is a columnar member formed of a magnetic material, for example, a carbon steel for mechanical structure or a martensitic stainless steel.

  Further, the output shaft 203 is provided with a retaining ring 142 that determines a relative position between the magnetic fluid seal 5 and the bearing portion 106, in other words, a relative position between the mounting portion 204 and the output shaft 203.

  The attachment portion 204 attaches the motor 2 to the vacuum vessel 11 and also functions as a seal portion that keeps the inside of the vacuum vessel 11 in a vacuum state. The attachment portion 204 is made of a nonmagnetic material, for example, a material such as austenitic stainless steel, aluminum alloy, or ceramics.

The attachment portion 204 is formed in a cylindrical shape, and a flange portion extending outward in the radial direction is formed at an end portion on the vacuum vessel 11 side. Inside the attachment portion 204, a bearing portion 206, a collar 151, a bearing portion 206, a collar 151, a magnetic fluid seal 5, a collar 151, and a bearing portion 206 are disposed from the vacuum vessel 11 toward the motor 2.
Furthermore, on the inner peripheral surface of the attachment portion 204, a flange portion 141 and a female screw portion 162 that is screwed with the bearing pressing portion 161 are formed.

The bearing unit 206 rotatably supports the output shaft 203 and is, for example, a deep groove ball bearing.
In the present embodiment, two bearing portions 206 are disposed inside the attachment portion 204, and two are disposed on the vacuum container 11 side and one on the motor 2 side of the magnetic fluid seal 5. In other words, the bearing portion 206 is disposed so as to sandwich the magnetic fluid seal 5.
Further, a collar 151 is disposed between the bearing portion 206 and the magnetic fluid seal 5 and between the bearing portion 206 and the bearing portion 206.

  Note that the supply of the rotational driving force in the vacuum actuator 201 having the above-described configuration is the same as that in the first embodiment, and a description thereof will be omitted.

According to the above configuration, since the bearing portion 206 is disposed with the magnetic fluid seal 5 interposed therebetween, the posture of the output shaft 203 in the region where the magnetic fluid seal 5 is disposed is stabilized. Therefore, it is possible to suppress deterioration of the sealing performance in the magnetic fluid seal 5.
In particular, when a plurality of bearing portions 206 (two bearing portions 206 in the present embodiment) are disposed between the magnetic fluid seal 5 and the vacuum vessel 11, the posture of the output shaft 203 in the region where the magnetic fluid seal 5 is disposed. Is more stable.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the vacuum actuator of this embodiment is the same as that of the first embodiment, but the configuration of the bearing pressing portion is different from that of the third embodiment. Therefore, in the present embodiment, only the configuration of the bearing pressing portion will be described with reference to FIGS. 7 and 8, and description of other components and the like will be omitted.
FIG. 7 is a schematic diagram illustrating the configuration of the vacuum actuator according to the present embodiment. FIG. 8 is a partially enlarged view illustrating the configuration of the bearing pressing portion of FIG.
In addition, the same code | symbol is attached | subjected to the component same as 3rd Embodiment, and the description is abbreviate | omitted.

  As shown in FIGS. 7 and 8, the vacuum actuator 301 is provided with a bearing pressing portion 361 that holds the bearing portion 206 and the magnetic fluid seal 5 together with the flange portion 141.

  The bearing pressing portion 361 is a member formed in a ring plate shape or a cylindrical shape, and a male screw that meshes with a female screw portion formed in the attachment portion 204 is formed on the outer peripheral surface. A groove in which the first O-ring (seal portion) 362 is disposed is formed on the surface of the bearing pressing portion 361 facing the output shaft 204, that is, the inner peripheral surface. Furthermore, a second O-ring (seal part) 363 is disposed between the side surface of the bearing pressing part 361 on the vacuum container 11 side and the attachment part 204.

The first O-ring 362 and the second O-ring 363 are ring-shaped members even made of an elastic material, for example, a material such as rubber, and close the airtight between the motor 2 and the magnetic fluid seal 5.
Specifically, the first O-ring 362 seals between the output shaft 203 and the bearing pressing portion 361. The second O-ring 363 seals between the attachment portion 204 and the bearing pressing portion 361.

  Note that the supply of the rotational driving force in the vacuum actuator 201 having the above-described configuration is the same as that in the first embodiment, and a description thereof will be omitted.

According to the above configuration, it is possible to prevent a solvent (liquid) such as alcohol from entering the magnetic fluid seal 5 from the motor 2. Therefore, deterioration of the sealing performance of the magnetic fluid seal 5 can be prevented.
For example, when performing a leak check of the vacuum container 11, a solvent such as alcohol is applied to the outer surface of the vacuum container 11. At this time, liquid may also be applied to the motor 2 of the vacuum actuator 301 (usually, the motor 2 is not exposed to alcohol). If the first O-ring 362 and the second O-ring 363 are not provided, alcohol may enter the motor 2 and may also enter the bearing portion 206 and the magnetic fluid seal 5. However, the provision of the first O-ring 362 and the second O-ring 363 prevents liquid from entering the bearing portion 206 and the magnetic fluid seal 5. As a result, deterioration of the sealing performance of the magnetic fluid seal 5 can be prevented.

1, 101, 201, 301 Vacuum actuator 2 Motor (power generation unit)
3, 103, 203 Output shaft 4, 104, 204 Mounting part 5 Magnetic fluid seal 6, 106, 206 Bearing part 11 Vacuum vessel 107 Planetary speed reducer part (transmission part)
362 1st O-ring (seal part)
363 2nd O-ring (seal part)

Claims (4)

An output shaft disposed through the vacuum vessel and made of a magnetic material;
A power generation unit that rotationally drives the output shaft from the outside of the vacuum vessel;
Attached to the outer surface of the vacuum vessel and supports the power generation part, and an attachment part made of a non-magnetic material;
A magnetic fluid seal disposed between the output shaft and the mounting portion and partitioning the inside of the vacuum vessel and the power generation portion;
A bearing portion disposed in the vicinity of the magnetic fluid seal and rotatably supporting the output shaft;
A vacuum actuator characterized in that is provided.   The vacuum actuator according to claim 1, wherein a transmission unit that increases or decreases a torque transmitted from the power generation unit to the output shaft is provided between the power generation unit and the magnetic fluid seal. .   The at least one bearing part is disposed between the magnetic fluid seal and the power generation part, and at least one bearing part is disposed between the magnetic fluid seal and the vacuum vessel. The vacuum actuator according to 1 or 2.   The vacuum actuator according to any one of claims 1 to 3, further comprising a seal portion that hermetically partitions the power generation portion, the bearing portion, and the magnetic fluid seal.

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