Shock absorber

Patent metadata

Field	Value
Publication number	US-12031606-B2
Application number	US-202017620781-A
Country	US
Kind code	B2
Filing date	Mar 25, 2020
Priority date	Jun 26, 2019
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

Disclosed is a shock absorber including: a cylinder which is filled with a working fluid; a piston which is slidably provided in the cylinder and divides an inside of the cylinder into two chambers; a piston rod which is connected to the piston and extends outside the cylinder; a first passage and a second passage through which the working fluid flows due to movement of the piston; a first damping force generating mechanism which is provided in the first passage and generates a damping force; and a second damping force generating mechanism which is provided in the second passage and generates a damping force. The second damping force generating mechanism includes a sub valve provided on one side of the second passage, and a volume variable mechanism that changes a volume of a volume chamber provided in parallel with the second passage.

First claim

The invention claimed is:

1. A shock absorber comprising:
a cylinder which is filled with a working fluid;
a piston which is slidably provided in the cylinder and divides an inside of the cylinder into two chambers;
a piston rod which is connected to the piston and extends outside the cylinder;
a first passage and a second passage through which the working fluid flows due to movement of the piston;
a first damping force generating mechanism which is provided in the first passage and generates a damping force; and
a second damping force generating mechanism which is provided in the second passage and generates a damping force,
wherein the second damping force generating mechanism includes
a sub valve provided on one side of the second passage,
a volume variable mechanism that changes a volume of a volume chamber provided in parallel with the second passage, and
wherein, when a frequency thereof exceeds a predetermined frequency, a flow rate to the sub valve is limited by the volume variable mechanism.

2. The shock absorber according to claim 1 , wherein the volume variable mechanism includes the volume chamber and a moving member that moves to change the volume of the volume chamber.

3. The shock absorber according to claim 1 , wherein the first passage and the second passage are connected in series.

4. The shock absorber according to claim 1 , wherein the first passage and the second passage are connected in parallel.

5. A shock absorber comprising:
a cylinder which is filled with a working fluid;
a piston which is slidably provided in the cylinder and divides an inside of the cylinder into two chambers;
a piston rod which is connected to the piston and extends outside the cylinder;
a first passage and a second passage through which the working fluid flows due to movement of the piston;
a first damping force generating mechanism which is provided in the first passage and generates a damping force; and
a second damping force generating mechanism which is provided in the second passage and generates a damping force,
wherein the second damping force generating mechanism includes
one side sub valve provided on one side of a valve seat member passage portion provided in a valve seat member of the second passage, and
a bottomed tubular cap member provided between the piston and the valve seat member in the second passage,
wherein the valve seat member is provided in the cap member, and the one side sub valve is provided in a cap chamber between a bottom portion of the cap member and the valve seat member,
wherein, in the second passage, an orifice is disposed on an upstream side or a downstream side from the one side sub valve in flow by which the one side sub valve is opened,
wherein, in a region in which a piston speed is low, the one side sub valve is opened in a state in which a valve of the first damping force generating mechanism is closed,
wherein, in a speed region in which the piston speed is higher than that in the region in which the piston speed is low, the valve of the first damping force generating mechanism and the one side sub valve are both opened,
wherein a communication passage communicating with one chamber is formed at the bottom portion of the cap member,
wherein, in the cap chamber, between the one side sub valve and the bottom portion of the cap member, a movable moving member is provided, and
wherein the shock absorber further comprises a volume variable mechanism in which an intermediate chamber whose volume is changed by movement of the moving member is formed between the moving member and the one side sub valve.

6. The shock absorber according to claim 5 , further comprising:
the other side sub valve provided on the other side of the valve seat member passage portion and provided in the one chamber; and
a volume variable mechanism in which a volume chamber whose volume is changed by movement of the moving member is formed between the moving member and the other side sub valve via the one chamber.

7. The shock absorber according to claim 6 , wherein an O-ring is provided at least one of between the moving member and the bottom portion of the cap member and between the moving member and the one side sub valve.

8. The shock absorber according to claim 6 , wherein the moving member is supported by two conical disk springs, and the conical disk springs are disposed such that their concave sides face each other in a natural state.

9. A shock absorber comprising:
a cylinder which is filled with a working fluid;
a piston which is slidably provided in the cylinder and divides an inside of the cylinder into two chambers;
a piston rod which is connected to the piston and extends outside the cylinder;
a first passage and a second passage through which the working fluid flows from the chamber on an upstream side to the chamber on a downstream side in the cylinder due to movement of the piston;
a first damping force generating mechanism which is provided in the first passage formed in the piston and generates a damping force; and
a second damping force generating mechanism which is provided in an annular valve seat member disposed in one of the two chambers, is provided in the second passage which is parallel to the first passage, and generates a damping force,
wherein the second damping force generating mechanism includes
a first sub valve provided on one side of a valve seat member passage portion provided in the valve seat member of the second passage and a second sub valve provided on the other side thereof, and
a bottomed tubular cap member provided between the piston and the valve seat member in the second passage,
wherein the valve seat member is provided in the cap member, the first sub valve is provided in the one chamber, and the second sub valve is provided in a cap chamber between a bottom portion of the cap member and the valve seat member,
wherein, in the second passage, an orifice is disposed on an upstream side or a downstream side from the first sub valve in flow by which the first sub valve is opened,
wherein, in a region in which a piston speed is low, a valve of the second damping force generating mechanism is opened in a state in which a valve of the first damping force generating mechanism is closed,
wherein, in a speed region in which the piston speed is higher than that in the region in which the piston speed is low, the valve of the first damping force generating mechanism and the valve of the second damping force generating mechanism are both opened,
wherein a communication passage communicating with the one chamber is formed at the bottom portion of the cap member,
wherein, in the cap chamber, between the second sub valve and the bottom portion of the cap member, a flexible member that closes the communication passage is provided, and
wherein an intermediate chamber of which communication with the communication passage is blocked by the flexible member is formed between the flexible member and the second sub valve.

10. The shock absorber according to claim 9 , wherein a flexible member side protruding portion which is constantly in contact with the bottom portion of the cap member is integrally formed with the flexible member.

11. The shock absorber according to claim 9 , wherein a cap member side protruding portion which is constantly in contact with the flexible member is integrally formed with the bottom portion of the cap member.

12. The shock absorber according to claim 9 , wherein the valve seat member passage portion has a passage portion on an extension side and a passage portion on a contraction side, and a plurality of the passage portions on an extension side and a plurality

Assignees

• Hitachi Astemo Ltd

Inventors

• Yamashita Mikio
• KOTANI Takamasa

Classifications

• F16F2234/02

  cylindrical · CPC title

• F16F2232/08

  Linear · CPC title

• F16F2228/066

  Variable stiffness · CPC title

• F16F2222/12

  Fluid damping · CPC title

• F16F13/007

  the damper being a fluid damper · CPC title