Bi-directional shock absorbing device

Patent metadata

Field	Value
Publication number	US-9677639-B2
Application number	US-201314409680-A
Country	US
Kind code	B2
Filing date	May 29, 2013
Priority date	Jun 21, 2012
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A bidirectional shock absorber includes a cylinder housing including a liquid chamber, a shock-absorbing mechanism located inside the liquid chamber and supported by a rod sticking out of the cylinder housing. The shock-absorbing mechanism includes a pair of pistons located in the liquid chamber and attached to the rod on the respective sides of a liquid storage chamber constituting an accumulator, resistance paths formed between an outer circumferential surface of the pistons and an inner circumferential surface of a piston chamber, to apply flow resistance to the liquid, and unidirectional flow paths formed along the respective pistons and configured to block the liquid flow toward the liquid storage chamber when the corresponding piston is pressed toward the piston chamber, but to permit the liquid to flow in the opposite direction.

First claim

The invention claimed is:

1. A bidirectional shock absorber comprising: a cylinder housing including therein a liquid chamber filled with a liquid; a rod having an end portion located inside the liquid chamber and the other end portion liquid-tightly sticking out of the liquid chamber to outside of the cylinder housing, the rod being disposed so as to reciprocate in an axial direction; and a shock-absorbing mechanism located inside the liquid chamber and supported by the rod, the shock-absorbing mechanism being configured to shock-absorbingly stop a relative movement between the cylinder housing and the rod originating from an external force relatively exerted on the cylinder housing and the rod in a pressing direction or a pulling direction,
wherein the shock-absorbing mechanism includes: a first and a second piston which are able to be displaced separately in the axial direction on the rod by the action of liquid pressure, and which are supported by the rod at different positions in the axial direction; a first and a second piston chamber respectively defined by the first and the second piston; a liquid storage chamber formed between the first piston and the second piston; resistance paths respectively formed between an outer circumferential surface of the first and the second piston and an inner circumferential surface of the liquid chamber, the resistance paths being configured to apply flow resistance to the liquid; and a first and a second unidirectional flow path respectively connecting between the first and the second piston chamber and the liquid storage chamber,
the first and the second unidirectional flow paths are openable and closable by displacement of the first and the second pistons with respect to the rod and, when the rod is reciprocating, one of the unidirectional flow paths located ahead of the rod in the moving direction is closed by displacement, with respect to the rod, of the respective piston located on the forward side in the moving direction, so as to block the flow of the liquid flowing from the piston chamber on the forward side in the moving direction toward the liquid storage chamber, and that the other unidirectional flow path located behind the rod in the moving direction is opened by displacement, with respect to the rod, of the respective piston located on the rear side in the moving direction, so as to allow the liquid to flow from the liquid storage chamber to the piston chamber on the rear side in the moving direction.

2. The bidirectional shock absorber according to claim 1 ,
wherein the rod includes a first and a second partition walls of a flange shape formed with a predetermined clearance therebetween in the axial direction,
the first and the second piston are located adjacent to the respective partition walls on an outer of the clearance, so as to be displaced with respect to the rod in the axial direction, and to alternately abut against and separate from the first and the second partition walls by being displaced by the reciprocal motion of the rod, and
the first and the second unidirectional flow path each include a communication path formed between an inner circumferential surface of the corresponding piston and an outer circumferential surface the rod so as to constantly allow communication with the corresponding piston chamber, and an open/close path formed between the corresponding partition wall and the corresponding piston to permit and restrict communication between the communication path and the liquid storage chamber, and the open/close path is opened and closed when the corresponding piston separates from and abuts against the corresponding partition wall.

3. The bidirectional shock absorber according to claim 2 ,
wherein the first and second piston each include a recessed groove formed in a radial direction on a surface opposing the corresponding piston chamber, so as to constantly allow communication between the communication path and the corresponding piston chamber.

4. The bidirectional shock absorber according to claim 1 ,
wherein an inner diameter of the liquid chamber is largest at a position between the first piston chamber and the second piston chamber, and gradually decreases toward each of the first piston chamber and the second piston chamber.

5. The bidirectional shock absorber according to claim 1 ,
wherein the liquid storage chamber includes an accumulator constituted of an elastic member formed of an expandable and compressible synthetic resin foam body containing independent voids, and the cylinder housing includes a supply hole for supplying the liquid to the liquid chamber, so that the liquid chamber is filled with the liquid supplied from the supply hole, the liquid being subjected to a preload applied thereto, and the elastic member is compressed by the preload.

6. An actuator with bidirectional shock absorber, comprising the bidirectional shock absorber according to claim 1 , the actuator further comprising: a drive rod driven by a drive mechanism so as to linearly reciprocate; and a moving member driven to reciprocate by the drive rod, wherein the bidirectional shock absorber is attached to the actuator such that the rod of the bidirectional shock absorber reciprocates along an axial line parallel to the drive rod, and the rod of the bidirectional shock absorber is connected to the moving member.

7. The bidirectional shock absorber according to claim 2 ,
wherein the rod includes: a shock-absorbing mechanism support member that supports the shock-absorbing mechanism in the liquid chamber; and an external force transmitting portion connected to the shock-absorbing mechanism support member and sticking out of the cylinder housing, and the first and the second partition walls and the second piston are provided on the shock-absorbing mechanism support member, and the first piston is provided on the external force transmitting portion.

8. The bidirectional shock absorber according to claim 3 ,
wherein the rod includes: a shock-absorbing mechanism support member that supports the shock-absorbing mechanism in the liquid chamber; and an external force transmitting portion connected to the shock-absorbing mechanism support member and sticking out of the cylinder housing, and the first and the second partition walls and the second piston are provided on the shock-absorbing mechanism support member, and the first piston is provided on the external force transmitting portion.

9. The bidirectional shock absorber according to claim 2 ,
wherein an inner diameter of the liquid chamber is largest at a position between the first piston chamber and the second piston chamber, and gradually decreases toward each of the first piston chamber and the second piston chamber.

10. The bidirectional shock absorber according to claim 3 ,
wherein an inner diameter of the liquid chamber is largest at a position between the first piston chamber and the second piston chamber, and gradually decreases toward each of the first piston chamber and the second piston chamber.

Assignees

• Smc Corp

Inventors

• Miyasato Eiko
• Takakuwa Youji
• Yoshinaga Kodai
• Mita Tsuyoshi
• Matsuzaki Kouichi
• Minakuchi Toshio
• Iida Kazuhiro
• Kaneko Junya

Classifications

• F16F9/483 Primary

  characterised by giving a particular shape to the cylinder, e.g. conical · CPC title

• F15B15/228

  having shock absorbers mounted outside the actuator housing · CPC title

• F15B15/22

  for accelerating or decelerating the stroke · CPC title

• F16F9/19 Primary

  with a single cylinder {and of single-tube type} · CPC title

• F16F9/3214

  of pistons (F16F9/0227 and F16F9/36 take precedence; throttling passages in or on piston body F16F9/3405) · CPC title