Linear actuator and vacuum control device

Patent metadata

Field	Value
Publication number	US-9234586-B2
Application number	US-201414519426-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Apr 23, 2012
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

A linear actuator is used with a vacuum chamber in which plasma is generated. The linear actuator comprises a moving member extending between the exterior and the interior of the vacuum chamber through an opening provided in the vacuum chamber so as to be rectilinearly reciprocated, a drive section configured to reciprocate the moving member, a cover that covers the moving member, and a slide seal section that provides a seal between the interior and the exterior of the vacuum chamber while allowing the cover to slide thereon. The cover covers a range of the moving member which is moved into both of the interior and the exterior of the vacuum chamber while the moving member is reciprocated by the drive section, and an outer surface of the cover is smaller in the amount of gas adsorption per unit area than an outer surface of the moving member.

First claim

What is claimed:

1. A linear actuator for use with a vacuum chamber in which plasma is generated, comprising
a moving member which extends between the exterior and the interior of the vacuum chamber through an opening provided in the vacuum chamber and which is configured to be rectilinearly reciprocated;
a drive section which is configured to reciprocate the moving member;
a cover for covering the moving member; and
a slide seal section for providing a seal between the interior and the exterior of the vacuum chamber while allowing the cover to slide thereon;
wherein
the cover covers a range of the moving member which is moved into both of the interior and the exterior of the vacuum chamber in the course of reciprocation of the moving member by the drive section, and
an outer surface of the cover is smaller in the amount of gas adsorption per unit area than an outer surface of the moving member.

2. The linear actuator according to claim 1 , wherein the moving member has an attachment section provided at its end on the side in the interior of the vacuum chamber, the attachment section having an amount of gas adsorption per unit area larger than that of the outer surface of the cover.

3. The linear actuator according to claim 1 , wherein the cover comprises an electrically insulating sintered body formed through firing of an electrically insulating nonmetallic material.

4. The linear actuator according to claim 3 , wherein the sintered body is formed of ceramic formed through firing of aluminum oxide.

5. The linear actuator according to claim 1 , wherein the moving member is formed of a metal material.

6. The linear actuator according to claim 5 , wherein the moving member is formed of aluminum.

7. The linear actuator according to claim 2 , wherein the attachment section is formed of a metal material whose surface is subjected to surface oxidization.

8. The linear actuator according to claim 7 , wherein
the attachment section is formed of aluminum, and
the surface oxidization is alumite treatment.

9. The linear actuator according to claim 1 , further comprising
a guide rod connected to the moving member and extending along an axis of the moving member, and
a guide for guiding the guide rod along a moving direction of the moving member.

10. The linear actuator according to claim 2 , further comprising an operation member which is attached to the attachment section and is configured to operate in the interior of the vacuum chamber.

11. The linear actuator according to claim 10 , further comprising an insertion passage for allowing a control line for controlling operation of the operation member to be inserted into the operation member from the exterior of the vacuum chamber.

12. The linear actuator according to claim 1 , wherein
the cover is provided such that a predetermined gap is formed between the same and an outer surface of the moving member through a pair of elastic seal members which are disposed away from each other in a moving direction of the moving member, and
the pair of elastic seal members is elastically in contact with the outer surface of the moving member and seals the predetermined gap.

13. The linear actuator according to claim 1 , wherein
the slide seal section has
a slide surface on which the cover slides,
a first slide seal member and a second slide seal member which are disposed away from each other in a moving direction of the moving member and which define a vacuum slide chamber between the slide surface and the cover, and
a vacuum evacuation channel which communicates with the vacuum slide chamber;
the first slide seal member is in contact with an outer surface of the cover and provides a seal between the vacuum slide chamber and the interior of the vacuum chamber;
the second slide seal member is in contact with the outer surface of the cover and provides a seal between the vacuum slide chamber and the exterior of the vacuum chamber as well as the exterior of the vacuum slide chamber; and
the vacuum slide chamber is vacuum-evacuated through the vacuum evacuation channel.

14. The linear actuator according to claim 13 , wherein the first slide seal member has an elastic member having a forked lip whose lip pieces are in contact with the slide surface and the cover, respectively, and
an urging member which urges the lip pieces of the forked lip toward mutually opposite directions.

15. A vacuum control device comprising
a control unit for controlling a linear actuator according to claim 13 ,
wherein the control unit has a conductance adjustment mode for controlling the drive section such that a range of the moving member which is moved into the interior of the vacuum chamber in the course of reciprocation of the moving member by the drive section is moved within a range from the interior of the vacuum chamber to the interior of the vacuum slide chamber.

16. The vacuum control device according to claim 15 , wherein the control unit has a desorption mode for, before start of the conductance adjustment mode, vacuum-evacuating the vacuum slide chamber through the vacuum evacuation channel for a predetermined period of time in a condition in which a range of the moving member having been moved from the interior of the vacuum chamber to the exterior of the vacuum slide chamber in the course of reciprocation of the moving member by the drive section is moved into the vacuum slide chamber.

17. The linear actuator according to claim 1 , wherein
the drive section comprises
a cylinder which is disposed externally of the vacuum chamber and into which working fluid flows,
a piston disposed within the cylinder in such a manner as to define a working chamber, and being configured to be moved within the cylinder by pressure of the working fluid supplied into the working chamber, and
an urging member being configured to urge the piston toward the vacuum chamber; and
the moving member is connected to the piston.

Assignees

• Ckd Corp

Inventors

• Kouketsu Masayuki
• Itafuji Hiroshi

Classifications

• F16J1/01 Primary

  characterised by the use of particular materials (F16J1/02 takes precedence) · CPC title

• F16K41/04

  with at least one ring of rubber or like material between spindle and housing · CPC title

• F16K31/1221

  one side of the piston being spring-loaded · CPC title

• F16K51/02

  specially adapted for high-vacuum installations · CPC title

• F15B15/1461 Primary

  Piston rod sealings · CPC title