Cylinder apparatus

Patent metadata

Field	Value
Publication number	US-11073190-B2
Application number	US-201716473334-A
Country	US
Kind code	B2
Filing date	Dec 26, 2017
Priority date	Dec 26, 2016
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Electrorheological fluid is loaded in a shock absorber ( 1 ) as hydraulic fluid ( 2 ). The shock absorber ( 1 ) controls a generated damping force by causing a potential difference to be generated in an electrode passage ( 19 ) and controlling a viscosity of the electrorheological fluid passing through this electrode passage ( 19 ). A plurality of partition walls ( 20 ) is provided between an inner cylinder ( 3 ) and an electrode cylinder ( 18 ). By being configured in this manner, the shock absorber ( 1 ) forms a plurality of helical flow passages ( 21 ) between the inner cylinder ( 3 ) and the electrode cylinder ( 18 ). In this case, an inclination angle of each of the partition walls ( 20 ) is not constant, and each of the partition walls ( 20 ) includes a sharply inclined portion ( 20 A) inclined at a large angle on at least an entrance side of an extension-side flow passage ( 21 ).

First claim

The invention claimed is:

1. A cylinder apparatus sealingly containing functional fluid having a fluid property changing according to an electric field, the cylinder apparatus including a rod inserted therein, the cylinder apparatus comprising:
an inner cylinder electrode and an outer cylinder electrode provided outside this inner cylinder electrode, the inner cylinder electrode and the outer cylinder electrode serving as electrodes of potentials different from each other; and
one or a plurality of flow passage formation unit(s) provided between the inner cylinder electrode and the outer cylinder electrode, the one or plurality of flow passage formation unit(s) forming a plurality of flow passages through which the functional fluid flows at least according to an extension-side movement of the rod from one end side toward an opposite end side in an axial direction,
wherein the flow passages formed by the one or plurality of flow passage formation unit(s) are each a helical or serpentine flow passage having a circumferentially extending portion, and provided in such a manner that an effective cross-sectional area of the flow passage on at least one of an entrance and an exit is large compared to an effective cross-sectional area of an intermediate portion of this flow passage,
wherein the flow passage formation unit(s) comprise(s) one or a plurality of seal unit(s) provided so as to be inclined at some inclination angle with respect to the axial direction, and
wherein the inclination angle of each of the seal unit(s) is not constant, and a sharply inclined portion inclined at a large inclination angle is provided at least on an entrance of an extension-side flow passage.

2. The cylinder apparatus according to claim 1 , wherein the sharply inclined portion includes a portion extending obliquely with respect to an axial direction of the outer cylinder electrode.

3. The cylinder apparatus according to claim 1 , wherein the sharply inclined portion includes a portion extending in parallel with the axial direction of the outer cylinder electrode.

4. The cylinder apparatus according to any of claim 1 , wherein each of the seal unit(s) includes a bent portion at an intermediate portion thereof, and
wherein the sharply inclined portion is divided into a plurality of portions with a boundary therebetween lying at the bent portion.

5. The cylinder apparatus according to any of claim 1 , wherein the sharply inclined portion is provided on both the entrance side of the extension-side flow passage and an entrance side of a compression-side flow passage.

6. The cylinder apparatus according to claim 4 , wherein the bent portion is formed as a curved connection portion.

7. The cylinder apparatus according to claim 1 , wherein the outer cylinder electrode partially flares.

8. The cylinder apparatus according to claim 1 , wherein the number of the flow passage formation unit(s) provided on the exit is less than the number of the flow passage formation unit(s) at the intermediate portion of the flow passage.

9. The cylinder apparatus according to claim 1 , wherein the effective cross-sectional area is changed by changing an angle of each of the flow passage formation unit(s).

Assignees

• Hitachi Automotive Systems Ltd
• Hitachi Astemo Ltd

Inventors

• Aoki Yasuhiro
• Tanabe Umi

Classifications

• B60G2202/24

  Fluid damper · CPC title

• B60G2800/162

  Reducing road induced vibrations · CPC title

• B60G2206/41

  Dampers · CPC title

• F16F9/532 Primary

  Electrorheological [ER] fluid dampers · CPC title

• F16F9/369

  Sealings for elements other than pistons or piston rods, e.g. valves · CPC title