Hydraulic damper

• US 4,463,839 A
• Filed: 11/04/1982
• Issued: 08/07/1984
• Est. Priority Date: 11/06/1981
• Status: Expired due to Fees

• Current Assignee: Tokico Limited (Hitachi, Ltd.)
• Original Assignee: Tokico Limited (Hitachi, Ltd.)
• Inventors: Ashiba, Masahiro
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US06/439,718
• Time in Patent Office: 642 Days
• Field of Search: 188/318, 188/319, 188/282, 188/286, 188/285, 188/299, 188/314, 188/315, 188/316, 188/317, 188/322.13, 188/322.15, 267/64.15-64.18, 251/205-209
• US Class Current: 188/282.4
• CPC Class Codes: F16F 9/462 Rotary actuation means

Abstract

A hydraulic damper including a piston working in a cylinder and partitioning the interior thereof into two liquid chambers, a damping force generating valve device mounted on the piston to act both in extension and contraction strokes, a piston rod secured to the piston and having a coaxial bore and a radial hole to constitute a by-pass passage connecting the two liquid chambers by-passing the damping force generating valve device, a valve member provided in the by-pass passage and steppingly controlling the effective area thereof, and an actuating rod extending in the coaxial bore with the inner end being secured to the valve member. An operating mechanism is mounted on the piston rod and comprises an electromagnetic solenoid, a vertically reciprocable slide connected to the solenoid, a rotor connected to the actuating rod and having saw-teeth projections thereon, and a fixed guide cooperating with the rotor and the slide to rotate the rotor by one pitch of saw-teeth projections in response to one reciprocation of the slide.

Claims

1. A hydraulic damper including a generally vertical cylinder receiving therein hydraulic liquid, a piston working in the cylinder and partitioning the interior thereof into two liquid chambers, one or a pair of damping force generating valves mounted on the piston for generating the damping force both in the extension and contraction strokes of the damper, a piston rod secured to the piston and extending through the upper end of the cylinder to the outside, a coaxial bore and a radial hole formed in the piston rod to constitute a by-pass passage connecting said two liquid chambers, an adjustable valve member for steppingly controlling the effective area of the by-pass passage, and an actuating rod extending through said coaxial bore in the piston rod with the inner end thereof being secured to said valve member, characterized by

a guide member having a bore coaxial with the actuating rod and being mounted on the upper end of the piston rod,

a rotor rotatably disposed in said bore in the guide member and being normally biassed upward by a spring and associated with the actuating rod,

saw-teeth like projections and recesses formed on the upper end of the rotor and being spaced with each other along the circumference thereof,

at least one fixed guide projecting in said bore in the guide member for normally engaging with either one of the recesses thereby restricting the upward movement and the rotation of said rotor,

a vertically displaceable guide guided by said fixed guide and having on the lower end thereof at lease one projection for engaging with either one of said saw-teeth shaped projections on the rotor, whereby said rotor rotates by one tooth of said saw-teeth shaped projections in response to each reciprocal movement of said displaceable guide, and

an electromagnetic solenoid connected to said displaceable guide.

2. A hydraulic damper according to claim 1 wherein said adjustable valve member is rotatable around the axis of said actuating rod with an arcuate outer circumference thereof cooperating with the inner circumference of a hollow nut which is disposed in the lower liquid chamber and connects the lower end of the piston rod with the piston,

a plurality of radial holes are formed in said hollow nut which permanently open to the lower liquid chamber and are selectively closed in response to the rotation of said valve member, and

the upper end of the actuating rod is non-rotatably but vertically displaceably connected to said rotor.

3. A hydraulic damper according to claim 1 wherein said adjustable valve member is verically slidably engaging with the inner circumference of a hollow nut which is disposed in the lower liquid chamber and connects the lower end of the piston rod with the piston,

a plurality of radial holes are formed in said hollow nut which permanently open to the lower liquid chamber and are selectively closed in response to the vertical sliding movement of said valve member,

a spring acts on the valve member for biasing the same in the upward direction,

the upper end of said actuating rod abuts relatively rotatably with said rotor,

a plurality of recesses having different axial depth are defined in said saw-teeth like projections for selectively engaging with said fixed guide thereby controlling the axial location of said rotor and, accordingly of said valve member in response to the rotational position of said rotor.