Method for manufacturing valve guide for a hydraulic damper

• US 4,495,790 A
• Filed: 07/16/1982
• Issued: 01/29/1985
• Est. Priority Date: 07/20/1981
• Status: Expired due to Term

• Current Assignee: Tokico Limited (Hitachi, Ltd.)
• Original Assignee: Tokico Limited (Hitachi, Ltd.)
• Inventors: Goto, Akio, Muto, Toshiaki
• Primary Examiner(s): Larson, Lowell A.
• Application Number:
  US06/399,133
• Time in Patent Office: 928 Days
• Field of Search: 72/325, 72/326, 72/348, 72/368, 72/370, 72/379, 188/322.14, 29/148.4 C, 29/149.5 C
• US Class Current: 72/326
• CPC Class Codes: B21D 53/00 Making other particular articles making wire fabrics B21F; making chains or chain parts B21L
• CPC Class Codes: F16F 2224/0241 Fibre-reinforced plastics [FRP]
• CPC Class Codes: F16F 9/34 Special valve constructions F16F9/44, F16F9/50 take precedence; filtering details F16F9/3285 ; valves in general F16K; Shape or construction of throttling passages

Abstract

A hydraulic damper includes a cylinder, a piston slidably disposed in the cylinder and partitioning the interior of the cylinder into first and second oil chambers, a rod secured to the piston and extending through the first chamber to the outside, and a damping force generating valve mechanism provided in the cylinder and at one end of the second oil chamber. The valve mechanism comprises a bottom member defining an annular valve seat thereon, a flexible valve disc cooperating with the valve seat, and a novel generally tubular valve guide. The valve guide has a plurality of large and small diameter portions formed integrally and alternately along the circumference thereof, the inner circumference of the small diameter portions defining guide surfaces for guiding the outer circumference of the valve disc and axial passages along the outer circumference thereof, and the large diameter portions defining axial passages along the inner circumference thereof and which passages communicate with the first mentioned axial passages through cut-outs formed between the large and small diameter portions.

Claims

1. A method for manufacturing a valve guide for use in a hydraulic damper of the type including a cylinder, a piston slidably disposed in said cylinder and partitioning the interior of said cylinder into first and second oil chambers, a rod secured to said piston and extending through said first chamber to the outside, a damping force generating valve mechanism provided in said cylinder and at one end of said second oil chamber, said valve mechanism having a bottom member defining an annular valve seat thereon, a flexible valve disc cooperating with said valve seat, and a generally tubular said valve guide having a plurality of axially extending large and small diameter portions being formed integrally and alternately along the circumference thereof, said large and small diameter portions defining therebetween radially and axially extending cutouts which act as oil passages, said method comprising:

stamping or drawing a sheet metal member into a generally hat shaped configuration having an upper end wall, a cylindrical wall and a flange extending radially outwards from the lower end of said cylindrical wall;

cutting and die-forming a plurality of circumferentially spaced portions of said upper end wall and said cylindrical wall to form a plurality of circumferentially spaced small diameter cylindrical portions and a plurality of cut-outs defined between said small diameter cylindrical portions and remaining portions of said cylindrical wall; and

punching a central opening in the upper end wall.

2. A method for manufacturing a valve guide for use in a hydraulic damper of the type including a cylinder, a piston slidably disposed in said cylinder and partitioning the interior of said cylinder into first and second oil chambers, a rod secured to said piston and extending through said first chamber to the outside, a damping force generating valve mechanism provided in said cylinder and at one end of said second oil chamber, said valve mechanism having a bottom member defining an annular valve seat thereon, a flexible valve disc cooperating with said valve seat, and a generally tubular said valve guide having a plurality of axially extending large and small diameter portions being formed integrally and alternately along the circumference thereof, said large and small diameter portions defining therebetween radially and axially extending cutouts which act as oil passages, said method comprising:

stamping or drawing a sheet metal member into a generally hat shaped configuration having an upper end wall, large and small diameter cylindrical walls defining therebetween a radial step and a flange extending radially outwards from the lower end of the large diameter wall;

cutting and die-forming a plurality of circumferentially spaced portions of said small diameter cylindrical wall and said radial step to form a plurality of circumferentially spaced large diameter cylindrical wall portions the diameter of which is substantially equal to said large diameter wall, and a plurality of cut-outs defined between said large diameter portions and remaining portions of said small diameter wall; and

punching a central opening in the upper end wall.