Wheel suspension system and spring therefor

• US 6,460,835 B1
• Filed: 03/21/2000
• Issued: 10/08/2002
• Est. Priority Date: 07/27/1998
• Status: Expired due to Term

• Current Assignee: NHK Spring Company Limited
• Original Assignee: NHK Spring Company Limited
• Inventors: Shigeoka, Iwao, Kamakura, Toshiyuki, Komazaki, Masaya, Kato, Hirotake, Nakamura, Takahiro, Hamano, Toshio
• Primary Examiner(s): Lavinder, Jack
• Assistant Examiner(s): SY, MARIANO ONG
• Application Number:
  US09/509,289
• Time in Patent Office: 931 Days
• Field of Search: 267/221, 267/34, 267/259, 267/4, 267/180, 267/166, 267/170, 267/220, 267/167, 267/248, 267/286, 267/291, 280/124.146, 280/124.179, 280/124.141, 280/124.168
• US Class Current: 267/34
• CPC Class Codes: B60G 15/07 the damper being connected to the stub axle and the spring being arranged around the damper B60G15/068 takes precedence
• CPC Class Codes: B60G 2200/17 with a strut contributing to the suspension geometry by being articulated onto the wheel support
• CPC Class Codes: B60G 2202/12 Wound spring
• CPC Class Codes: B60G 2202/312 The spring being a wound spring
• CPC Class Codes: B60G 2204/1242 on a damper, e.g. MacPerson strut
• CPC Class Codes: B60G 2206/426 Coil springs having a particular shape, e.g. curved axis, pig-tail end coils
• CPC Class Codes: F16F 1/047 characterised by varying pitch

Abstract

Provided is a wheel suspension system (4) and a spring (6, 16, 26) therefor which can improve the ride comfort of the vehicle by reducing the sliding resistance between the cylinder and the piston of the tubular shock absorber (5) surrounded by the compression coil spring without increasing the size of the suspension system and without complicating the assembly work. The compression coil spring is adapted to produce lateral forces between two ends thereof as the compression coil spring is extended and compressed by forming the coil spring so as to have cyclically varying pitch angle for each turn of the coil wire.

Claims

1. A vehicle wheel suspension system comprising a tubular shock absorber, and a compression coil spring surrounding the shock absorber, wherein:

the compression coil spring consists of a coil spring which is wound around a true cylinder so as to have a cyclically varying pitch angle between a single local minimum and a single local maximum substantially at diametrically opposite positions for each turn for a substantial length of the spring, and retained so as to be extended and compressed along an upright axial line so as to produce lateral forces between two ends thereof as the compression coil spring is extended and compressed.

2. A vehicle wheel suspension system according to claim 1, wherein the lateral forces which are produced between the two ends are determined such that lateral forces which are produced between a piston and a cylinder of the shock absorber due to an offset between the line of action from a wheel and an axial line of the shock absorber may be minimized.

3. A vehicle wheel suspension system according to claim 1, wherein the compression spring has a substantially true cylindrical shape in an unstressed state thereof.

4. A compression coil spring which is wound around a true cylinder so as to have a cyclically varying pitch angle between a single local minimum and a single local maximum substantially at diametrically opposite positions for each turn for a substantial length of the spring.

5. A compression coil spring according to claim 4, wherein the compression spring has a substantially true cylindrical shape in an unstressed state thereof.