US 4,527,676 AGranted

Variable-damping-force shock absorber

AssigneeAtsugi Motor Parts Company, Limited

InventorsJunichi Emura, Issei Kanari, Hideaki Saito

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Abstract

A variable-damping-force shock absorber in which the motor for rotating the orifice adjuster is housed within the cylinder and the orifice-adjuster position sensor for outputting binary coded sensor signals is incorporated. Therefore, it is possible to reduce noise generated from the motor while improving the lifetime of the motor because mud or rain water will not adhere onto the motor and to improve the precision and the response speed in rotating the orifice adjuster because the adjuster can be feedback controlled in digital fashion. Further, since the driven shaft of the motor or the reduction gear is loosely coupled with the orifice adjuster in the axial direction thereof, it is possible to reduce the torque or the size of the motor, because fluid pressure is not directly applied to the driven shaft via the orifice adjuster.

Claims11

Dependent claims

A variable-damping-force shock absorber, which comprises:

(a) a cylinder (2) filled with a working fluid;
(b) a piston rod (3) sealably and reciprocably inserted into said cylinder at one end of said cylinder;
(c) a piston assembly (1) slidably fitted to said cylinder so as to divide the housing of said cylinder into an upper chamber and a lower chamber, said piston assembly being provided with damping-force generating means for restrictively allowing the working fluid to flow between upper and lower chambers divided by said piston assembly when said piston assembly moves to and fro within said cylinder;
(d) a tubular member (12), the lower end of which communicates with the lower chamber, for connecting said piston rod and said piston assembly, said tubular member being provided with a plurality of orifices of different diameters radially formed in the wall thereof at circumferentially spaced equal angular intervals to communicate with the upper chamber;
(e) an orifice adjuster (11) rotatably fitted to said tubular member, said adjuster being provided with an axial bore to communicate with the lower chamber and at least one cutout formed in the wall of the axial bore thereof to selectively communicate with at least one of the orifices formed in said tubular member;
(f) a motor (7) housed within a bored cavity of said piston rod and connected to said orifice adjuster for rotating said orifice adjuster;
(g) means for sensing the angular position of said orifice adjuster in digital fashion, said means being rotated by said motor together with said orifice adjuster;
and
(h) means for feedback controlling the revolution angle of said orifice adjuster for communication of the cutout formed in said orifice adjuster with at least one of the orifices formed in said tubular member, said control means being connected to said motor and said orifice adjuster angular position sensing means,
whereby part of the working fluid displaceably passed between the two fluid chambers is adjustably by-passed through the cutout of said orifice adjuster and the orifice of said tubular member in order to vary the damping force of the shock absorber, when said orifice adjuster is controlled by means of said motor housed within said piston rod and said feedback control means in digital fashion.

7 more elements

A variable-damping-force shock absorber, which comprises:

(a) a cylinder (2) filled with a viscous working fluid;
(b) a piston rod (3) sealably and reciprocably inserted into said cylinder at one end of said cylinder;
(c) a piston assembly (1) slidably fitted to said cylinder so as to divide the housing of said cylinder into an upper chamber and a lower chamber, said piston assembly being provided with damping-force generating means for restrictively allowing the working fluid to flow between the upper and lower chambers provided by said piston assembly when said piston assembly moves to and fro within said cylinder;
(d) a tubular member (12), the lower end of which communicates with the lower chamber, for connecting said piston rod and said piston assembly, said tubular member being provided with a plurality of orifices of different diameters radially formed in the wall thereof at circumferentially spaced equal angular intervals to communicate with the upper chamber;
(e) an orifice adjuster (11) rotatably fitted to said tubular member, said adjuster being provided with an axial bore to communicate with the lower chamber and at least one cutout formed in the wall of the axial bore thereof to selectively communicate with at least one of the orifices formed in said tubular member;
(f) a step motor (7) housed within a bored cavity of said piston rod and connected to said orifice adjuster for rotating said orifice adjuster;
(g) means for directly controlling the revolution angle of said step motor for communication of the cutout formed in said orifice adjuster with at least one of said orifices formed in said tubular member, said control means being connected to said step motor,
whereby part of the working fluid displaceably passed between the two fluid chambers is adjustably by-passed through the cutout of said orifice adjuster and the orifice of said tubular member in order to vary the damping force of the shock absorber, when said orifice adjuster is directly controlled by means of said step motor housed within said piston rod and said control means,
(h) wherein said orifice adjuster is formed with a slot, at one end thereof, into which a flat portion of a driven shaft of said motor is fitted and there is further provided a clearance between the slot and the driven shaft in the axial direction thereof, in order to prevent fluid pressure within the chamber from being directly applied to said motor via said orifice adjuster.

6 more elements

A variable-damping-force shock absorber, which comprises:

(a) cylinder (2) filled with a viscous working fluid;
(b) a piston rod (3) sealably and reciprocably inserted into said cylinder at one end of said cylinder;
(c) a piston assembly (1) slidably fitted to said cylinder so as to divide the housing of said cylinder into an upper chamber and a lower chamber, said piston assembly being provided with damping-force generating means for restrictively allowing the working fluid to flow between the upper and lower chambers provided by said piston assembly when said piston assembly moves to and fro within said cylinder;
(d) a tubular member (12), the lower end of which communicates with the lower chamber, for connecting said piston rod and said piston assembly, said tubular member being provided with a plurality of orifices of different diameters radially formed in the wall thereof at circumferentially spaced equal angular intervals to communicate with the upper chamber;
(e) an orifice adjuster (11) rotatably fitted to said tubular member, said adjuster being provided with an axial bore to communicate with the lower chamber and at least one cutout formed in the wall of the axial bore thereof to selectively communicate with at least one of the orifices formed in said tubular member;
(f) a step motor (7) housed within a bored cavity of said piston rod and connected to said orifice adjuster for rotating said orifice adjuster;
(g) means for directly controlling the revolution angle of said step motor for communication of the cutout formed in said orifice adjuster with at least one of said orifices formed in said tubular member, said control means being connected to said step motor,
whereby part of the working fluid displaceably passed between the two fluid chambers is adjustably by-passed through the cutout of said orifice adjuster and the orifice of said tubular member in order to vary the damping force of the shock absorber, when said orifice adjuster is directly controlled by means of said step motor housed within said piston rod and said control means,
(h) said shock absorber further comprising coupling means for coupling said step motor to said orifice adjuster, said coupling means comprising
shaft means driven by said step motor
receiving means of said orifice adjuster for receiving said driven shaft means, and
means for reducing torque loading on said step motor by said orifice adjuster.

9 more elements

Dependencies are inferred from the claim text.