US 6,981,577 B2 | ||
Controlling damping force shock absorber | ||
Yohei Katayama, Kanagawa-ken (Japan); Hiroyuki Matsumoto, Kanagawa-ken (Japan); Kenichi Nakamura, Kanagawa-ken (Japan); and Masaaki Uchiyama, Tokyo (Japan) | ||
Assigned to Kabushiki Kaisha Hitachi Seisakusho, Tokyo (Japan) | ||
Filed on Feb. 26, 2004, as Appl. No. 10/786,115. | ||
Claims priority of application No. 2003-096480 (JP), filed on Mar. 31, 2003. | ||
Prior Publication US 2004/0188200 A1, Sep. 30, 2004 | ||
Int. Cl. F16F 9/53 (2006.01) |
U.S. Cl. 188—267.2 | 9 Claims |
1. A controllable damping force shock absorber comprising:
a cylinder in which a variable viscosity fluid is sealably contained;
a piston slidably disposed in the cylinder in a fitted relationship so as to divide the interior of the cylinder into two
cylinder chambers;
a piston rod having one end connected to the piston and the other end extended to the outside of the cylinder; and
a damping force-controlling mechanism for generating a controlled damping force by controlling a flow of the variable viscosity
fluid caused by slidable movement of the piston,
the damping force-controlling mechanism including:
a damping valve having a pressure-receiving portion for receiving a pressure of the variable viscosity fluid in at least one
of an extension stroke and a compression stroke of the piston rod,
a pilot chamber provided behind the pressure-receiving portion, wherein a pressure in the pilot chamber is applied in a direction
for closing the damping valve so that the pilot chamber controls the opening of the damping valve and when the damping valve
is opened, the variable viscosity fluid is allowed to flow from one of the cylinder chambers to the other without passing
through the pilot chamber;
a pilot passage for allowing the variable viscosity fluid to flow through the pilot chamber according to slidable movement
of the piston; and
viscosity-changing means adapted to change viscosity of the variable viscosity fluid flowing through the pilot passage so
that the pressure in the pilot chamber varies depending on the change in the viscosity of the variable viscosity fluid.
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