Shock absorber

Patent metadata

Field	Value
Publication number	US-9834054-B2
Application number	US-201415022323-A
Country	US
Kind code	B2
Filing date	Sep 18, 2014
Priority date	Sep 19, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A shock absorber includes; a free piston that partitions the compression chamber into an expansion-side compression chamber and a contraction-side compression chamber; an expansion-side flow passage that connects the expansion-side chamber with the expansion-side compression chamber; a contraction-side flow passage that connects the contraction-side chamber with the contraction-side compression chamber; an expansion-side bypass valve provided in the expansion-side flow passage to admit only a flow directed from the expansion-side chamber to the expansion-side compression chamber and generate resistance; a contraction-side bypass valve provided in parallel with the expansion-side bypass valve to admit only a flow directed from the expansion-side compression chamber to the expansion-side chamber and generate resistance; an expansion-side elastic stopper configured to stop the free piston at an expansion-side stroke end; and a contraction-side elastic stopper configured to stop the free piston at a contraction-side stroke end.

First claim

The invention claimed is:

1. A shock absorber, comprising:
a cylinder;
a piston slidably inserted into the cylinder to partition the inside of the cylinder into an expansion-side chamber and a contraction-side chamber;
a piston rod movably inserted into the cylinder and provided with one end connected to the piston;
a damping passage that connects the expansion-side chamber with the contraction-side chamber;
a compression chamber;
a free piston movably inserted into the compression chamber to partition the compression chamber into an expansion-side compression chamber and a contraction-side compression chamber;
a spring member configured to generate a biasing force for suppressing displacement of the free piston with respect to the compression chamber;
an expansion-side flow passage that connects the expansion-side chamber with the expansion-side compression chamber;
a contraction-side flow passage that connects the contraction-side chamber with the contraction-side compression chamber;
an expansion-side bypass valve arranged closer to the expansion-side chamber side relative to the piston and provided in the expansion-side flow passage, the expansion-side bypass valve being configured to admit only a flow directed from the expansion-side chamber to the expansion-side compression chamber and generate resistance;
a contraction-side bypass valve arranged closer to the expansion-side chamber side relative to the piston and provided in the expansion-side flow passage in parallel with the expansion-side bypass valve, the contraction-side bypass valve being configured to admit only a flow directed from the expansion-side compression chamber to the expansion-side chamber and generate resistance;
an expansion-side elastic stopper configured to stop the free piston at an expansion-side stroke end;
a contraction-side elastic stopper configured to stop the free piston at a contraction-side stroke end, and
a bypass valve disc mounted closer to the expansion-side chamber side of the piston rod relative to the piston and included in a part of an expansion-side passage connected to the expansion-side chamber,
wherein the expansion-side bypass valve and the contraction-side bypass valve are mounted to the bypass valve disc.

2. The shock absorber according to claim 1 , wherein the bypass valve disc has a contraction-side bypass port and an expansion-side bypass port connected to the expansion-side chamber,
the piston rod has an internal passage that connects the expansion-side compression chamber to the expansion-side bypass port and the contraction-side bypass port,
the expansion-side bypass port, the contraction-side bypass port, and the internal passage constitute the expansion-side flow passage,
the expansion-side bypass valve is operated to open or close the expansion-side bypass port, and
the contraction-side bypass valve is operated to open or close the contraction-side bypass port.

3. The shock absorber according to claim 1 , wherein both the expansion-side bypass valve and the contraction-side bypass valve are formed by using a leaf valve.

4. The shock absorber according to claim 1 , wherein the expansion-side bypass valve and the contraction-side bypass valve are formed by using a single annular leaf valve for opening or closing the expansion-side flow passage by flexing an inner circumference side or an outer circumference side.

5. The shock absorber according to claim 1 , further comprising a housing that forms the compression chamber,
wherein the expansion-side elastic stopper has
an expansion-side cushion member provided in one of the free piston and the housing, and
an expansion-side stopper member provided in the other one of the free piston and the housing to face the expansion-side cushion member, and

the contraction-side elastic stopper has
a contraction-side cushion member provided in one of the free piston and the housing, and
a contraction-side stopper member provided in the other one of the free piston and the housing to face the contraction-side cushion member.

6. The shock absorber according to claim 5 , wherein the expansion-side cushion member and the contraction-side cushion member have a narrowing head shape.

Assignees

• Kyb Corp

Inventors

• Teraoka Takashi
• Inamitsu Kazutaka
• Masamura Tatsuya

Classifications

• B60G13/08 Primary

  hydraulic · CPC title

• F16F9/348

  Throttling passages in the form of annular discs {or other plate-like elements which may or may not have a spring action}, operating in opposite directions {or singly, e.g. annular discs positioned on top of the valve or piston body (F16F9/341, F16F9/3415 take precedence)} · CPC title

• F16F9/18

  with a closed cylinder and a piston separating two or more working spaces therein · CPC title

• F16F9/516

  resulting in the damping effects during contraction being different from the damping effects during extension {, i.e. responsive to the direction of movement (F16F9/504 takes precedence)} · CPC title

• B60G2202/24

  Fluid damper · CPC title