US 2011/0214955 A1Published application

Shock absorber

AssigneeHitachi Automotive Systems, Ltd.

InventorsAtsushi Maeda, Masaru Kouyama, Mikio Yamashita, Fumiyuki Yamaoka

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Abstract

A shock absorber includes a first passage and a second passage to which a working fluid flows out from one chamber in a cylinder by movement of a piston, a damping valve installed on the first passage and configured to regulate a flow of the working fluid caused by sliding of the piston to generate a damping force, a back pressure chamber applying an internal pressure to the damping valve in a closing direction of the damping valve, a back pressure chamber inflow oil passage introducing the working fluid from one chamber into the back pressure chamber, a pressure chamber provided in-between on the second passage, and a free piston installed in the pressure chamber so as to freely slide in the pressure chamber.

Claims20

Dependent claims

A shock absorber comprising:

a cylinder in which a working fluid is enclosed;
a piston slidably fitted into the cylinder and configured to partition an interior of the cylinder into two chambers;
a piston rod connected to the piston and configured to extend to an exterior of the cylinder;
first and second passages to which the working fluid flows out from one of the chambers of the interior of the cylinder by movement of the piston;
a damping valve installed on the first passage and configured to regulate a flow of the working fluid caused by sliding of the piston to generate a damping force;
a back pressure chamber applying an internal pressure to the damping valve in a closing direction of the damping valve;
a back pressure chamber inflow oil passage introducing the working fluid from the one of the chambers of the interior of the cylinder into the back pressure chamber;
a pressure chamber provided on the second passage;
and
a free piston movably installed in the pressure chamber.

7 more elements

A shock absorber comprising:

a cylinder in which a working fluid is enclosed;
a piston slidably fitted into the cylinder and configured to partition an interior of the cylinder into two chambers;
a piston rod connected to the piston and configured to extend to an exterior of the cylinder;
first and second passages to which the working fluid flows out from the one of the chambers of the interior of the cylinder by movement of the piston;
a damping valve installed on the first passage and configured to regulate a flow of the working fluid caused by sliding of the piston to generate a damping force;
a back pressure chamber applying an internal pressure to the damping valve in a closing direction of the damping valve;
a back pressure chamber inflow oil passage introducing the working fluid from the one of the chambers of the interior of the cylinder into the back pressure chamber;
a housing in which a flow passage corresponding to at least a part of the second passage is formed;
a free piston movably installed in the housing and configured to partition the second passage into an upstream side and a downstream side;
and
one or a plurality of elastic bodies interposed between the free piston and the housing,
wherein at least one of a free piston contact surface of the free piston with which the elastic body is in contact and a housing contact surface of the housing with which the elastic body is in contact includes an inclined surface that is inclined to a moving direction of the free piston, and a shortest distance between a portion that is in contact with the elastic body within the free piston contact surface and a portion that is in contact with the elastic body within the housing contact surface is changed by movement of the free piston.

9 more elements

Dependencies are inferred from the claim text.