Multistage piston actuator

Patent metadata

Field	Value
Publication number	US-9995322-B2
Application number	US-201415516849-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Oct 7, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A multistage piston actuator exerts a driving pressure against a spring pressure into pressure chambers of piston bodies, fitted into a cylinder body, to operate the push rod. Each piston body is combined with a partition fitted into the cylinder body. Each piston body includes a pressure receiving plate portion, and an axial rod and a slidable cylindrical guide portion extending concentrically in opposite directions, the axial rod having an axial air passage connected to the pressure chambers. Each partition includes a base plate portion having a through-hole which receives the axial rod of an adjacent piston body, a large-diameter outermost cylindrical portion fitted into the cylinder body, and a slidable cylindrical guide portion slidably fit-engaged with the slidable cylindrical guide portion of the piston body. The axial rods of each piston body are brought into contact to operate the push rod.

First claim

What is claimed is:

1. A multistage piston actuator, comprising:
a cylinder body;
a plurality of piston bodies, which are fitted into said cylinder body; and
a push rod,
wherein said multistage piston actuator exerts a driving pressure against a spring pressure into pressure chambers of said plurality of piston bodies to thereby operate said push rod,

wherein each of said plurality of piston bodies is combined with a partition which is fitted into said cylinder body, said pressure chambers being formed between said piston bodies and said partitions, respectively,
wherein each of said piston bodies includes a pressure receiving plate portion, and an axial rod and a slidable cylindrical guide portion which extend concentrically with an axis line in opposite directions from either side of said pressure receiving plate portion, said axial rod having an axial air passage that is communicably connected to said pressure chambers,
wherein each of said partitions includes a base plate portion having a through-hole which receives said axial rod of an adjacent piston body of said piston bodies, and a large-diameter outermost cylindrical portion and a slidable cylindrical guide portion which extend concentrically with said axis line from one side of said base plate portion, said large-diameter outermost cylindrical portion being fitted into said cylinder body, and said slidable cylindrical guide portion being slidably fit-engaged with said slidable cylindrical guide portion of an associated piston body of said piston bodies,
wherein a large-diameter sealing member is inserted in between an inner peripheral surface of said large-diameter outermost cylindrical portion and said base plate portion of said partition and said pressure receiving plate portion and an outer peripheral surface of said slidable cylindrical guide portion of said associated piston body,
wherein a small-diameter sealing member is inserted in between an inner peripheral surface of said slidable cylindrical guide portion and said base plate portion of said partition and an outer peripheral surface of said axial rod of said adjacent piston body,
wherein said slidable cylindrical guide portion of each piston body has a simple cylindrical shape, so that no groove having a U-shaped cross section for engaging said large-diameter sealing member is formed therein, and
wherein said axial rods of said plurality of piston bodies are mutually brought into mechanical contact to thereby operate said push rod.

2. The multistage piston actuator according to claim 1 , wherein axial positions of said large-diameter sealing member and said small-diameter sealing member overlap each other at least when said associated piston body and said partition are positioned close to each other.

3. The multistage piston actuator according to claim 2 , wherein said slidable cylindrical guide portion of said partition has a simple cylindrical shape, so that no groove having a U-shaped cross section for engaging said small-diameter sealing member is formed therein.

4. An on/off valve mechanism comprising said multistage piston actuator according to claim 2 and an on/off valve which includes a valve body that is opened and closed via said push rod of said multistage piston actuator.

5. The multistage piston actuator according to claim 1 , wherein said slidable cylindrical guide portion of said partition has a simple cylindrical shape, so that no groove having a U-shaped cross section for engaging said small-diameter sealing member is formed therein.

6. An on/off valve mechanism comprising said multistage piston actuator according to claim 5 and an on/off valve which includes a valve body that is opened and closed via said push rod of said multistage piston actuator.

7. The multistage piston actuator according to claim 5 , wherein said axial rod of each piston body has a simple rod shape, so that no groove having a U-shaped cross section for engaging said small-diameter sealing member is formed therein.

8. An on/off valve mechanism comprising said multistage piston actuator according to claim 7 and an on/off valve which includes a valve body that is opened and closed via said push rod of said multistage piston actuator.

9. An on/off valve mechanism comprising said multistage piston actuator according to claim 1 and an on/off valve which includes a valve body that is opened and closed via said push rod of said multistage piston actuator.

10. A multistage piston actuator, comprising:
a cylinder body;
a plurality of piston bodies, which are fitted into said cylinder body; and
a push rod,

wherein said multistage piston actuator exerts an operational pressure against a spring pressure into pressure chambers of said plurality of piston bodies to thereby operate said push rod,
wherein each of said plurality of piston bodies is combined with a partition which is fitted into said cylinder body, said pressure chambers being formed between said piston bodies and said partitions, respectively,
wherein each of said piston bodies includes a flat plate-shaped pressure receiving plate portion orthogonal to an axis line, and a simple rod-shaped axial rod and a simple cylinder-shaped slidable cylindrical guide portion which extend concentrically with said axis line in opposite directions from either side of said pressure receiving plate portion, said simple rod-shaped axial rod having an axial air passage that is communicably connected to said pressure chambers,
wherein each said partitions includes a flat plate-shaped base plate portion that is orthogonal to said axis line and has a through-hole which receives said axial rod of an adjacent one of said piston bodies, and a large-diameter outermost cylindrical portion and a simple cylinder-shaped slidable cylindrical guide portion which extend concentrically with said axis line from one side of said base plate portion, said large-diameter outermost cylindrical portion being fitted into said cylinder body, and said simple cylinder-shaped slidable cylindrical guide portion being slidably fit-engaged with said slidable cylindrical guide portion of an associated piston body of said piston bodies,
wherein a large-diameter O-ring is inserted in an annular space formed between an inner peripheral surface of said large-diameter outermost cylindrical portion and said flat plate-shaped base plate portion of said partition and said flat plate-shaped pressure receiving plate portion and an outer peripheral surface of said slidable cylindrical guide portion of said associated piston body,
wherein a small-diameter O-ring is inserted in an annular space formed between an inner peripheral surface of said simple cylinder-shaped slidable cylindrical guide portion and said flat plate-shaped base plate portion of said partition and an outer peripheral surface of said simple rod-shaped axial rod of said piston body adjacent to said pressure receiving plate portion of said associated piston body,
wherein axial positions of said large-diameter O-ring and said small-diameter O-ring overlap each other at least when said piston body and said partition are positioned close to each other, and
wherein said axial rods of said plurality of piston bodies are mutually brought into mechanical contact to thereby operate said push rod.

11. An on/off valve mechanism comprising said multistage piston actuator according to claim 10 and an on/off valve which includes a valve body that is opened and closed via said push rod of said multistage piston actuator.

Assignees

• Fujikura Rubber Ltd
• Fujikin Kk

Inventors

• Ejiri Takashi
• Nakata Tomohiro
• Yakushijin Tadayuki

Classifications

• F15B15/1423 Primary

  Component parts; Constructional details · CPC title

• F15B15/1471

  Guiding means other than in the end cap (F15B15/1466 takes precedence) · CPC title

• F15B2015/1495

  with screw mechanism attached to the piston · CPC title

• F16H41/04

  Combined pump-turbine units · CPC title

• F15B15/1428

  Cylinders (F15B15/1438 takes precedence) · CPC title