Damping force control device for suspension system

• US 5,360,230 A
• Filed: 12/02/1991
• Issued: 11/01/1994
• Est. Priority Date: 11/30/1990
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Yamada, Naoki, Yamamoto, Junji
• Primary Examiner(s): CULBRETH, ERIC D
• Application Number:
  US07/801,419
• Time in Patent Office: 1,065 Days
• Field of Search: 280/707, 280/708, 280/714, 267/64.15, 188/269, 188/314, 180/41
• US Class Current: 280/5.515
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 2202/152 Pneumatic spring
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/20 Speed
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/51 in suspension unit
• CPC Class Codes: B60G 2400/82 Ground surface
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2500/20 Spring action or springs
• CPC Class Codes: B60G 2600/14 Differentiating means, i.e. differential control
• CPC Class Codes: B60G 2600/16 Integrating means, i.e. integral control
• CPC Class Codes: B60G 2600/184 Semi-Active control means
• CPC Class Codes: B60G 2600/604 low pass
• CPC Class Codes: B60G 2600/70 Computer memory; Data storage, e.g. maps for adaptive control
• CPC Class Codes: F16F 9/06 using both gas and liquid F16F9/486 take precedence; self-pumping fluid springs B60G17/044

Abstract

A damping force control device for a suspension system of a vehicle includes a shock absorber having a fluid chamber therein and provided at each wheel side of the vehicle, an orifice device for supplying an amount of fluid into the fluid chamber, and a control device for controlling the opening of the orifice device based on the vertical speed above the shock absorber.

Claims

1. A hydraulic shock absorber for a suspension system of a vehicle comprising:

a first cylinder;

a first piston slidably fitted in the first cylinder and defining a first chamber within the first cylinder;

a second cylinder;

a free piston slidably fitted in the second cylinder, said free piston defining a second chamber within the second cylinder that is located under the free piston;

a passage for establishing hydraulic communication between the first chamber and the second chamber;

adjustable opening orifice means disposed in the passage for controlling the hydraulic communication between the first chamber and the second chamber in order to adjust a damping force of the hydraulic shock absorber;

air spring means positioned in the second cylinder for adjusting a spring constant of the hydraulic shock absorber based on prevailing road conditions, said air spring means including a lower air spring positioned above the free piston, an electrically operated solenoid valve positioned above the lower air spring and an upper air spring positioned above the solenoid valve; and

control means for opening and closing the solenoid valve.

2. A hydraulic shock absorber as set forth in claim 1, wherein the control means controls the solenoid valve in accordance with a map which sets forth a relationship between the prevailing road conditions and a corresponding spring constant of the hydraulic shock absorber.

3. A hydraulic shock absorber as set forth in claim 1, including a pressure sensor operatively associated with the upper air spring and a pressure sensor operatively associated with the lower air spring.