VEHICLE DIFFERENTIAL INCLUDING PUMP WITH VARIABLE-ENGAGEMENT CLUTCH

• US 20090233748A1
• Filed: 05/29/2009
• Published: 09/17/2009
• Est. Priority Date: 09/09/2005
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Boddy, Douglas E.
• Granted Patent: US 8,043,184 B2
• Time in Patent Office: Days
• US Class Current: 475/88
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: F16D 29/00 Clutches and systems of clutches involving both fluid and magnetic actuation
• CPC Class Codes: F16D 37/02 the particles being magnetisable
• CPC Class Codes: F16D 43/28 actuated by fluid pressure
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 2048/423 characterised by bearing arrangement
• CPC Class Codes: F16H 2200/2071 using three freewheel mechanism
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/22 using friction clutches or brakes
• CPC Class Codes: F16H 48/30 using externally-actuatable means
• CPC Class Codes: F16H 48/32 using fluid pressure actuators
• CPC Class Codes: F16H 48/34 using electromagnetic or electric actuators
• CPC Class Codes: F16H 48/42 characterised by features of the input shafts, e.g. mounting of drive gears thereon

Abstract

A vehicle differential assembly is provided that includes a differential adapted to allow differing rotational speed between a pair of outputs. The differential includes a gear assembly connected to the outputs and one or more hydraulically-actuated clutches for selectively and variably coupling the outputs. A hydraulic pump is adapted to generate hydraulic fluid pressure for engagement of the hydraulically-actuated clutches. A variable-engagement clutch is operatively connected to the input and the hydraulic pump such that the input selectively drives the hydraulic pump during engagement of the clutch to provide hydraulic fluid pressure to the hydraulically-actuated clutches. A valve operatively connected to the hydraulic pump and the hydraulically-actuated clutches to selectively and variably provides fluid pressure from the hydraulic pump to the hydraulically-actuated clutches. A method of controlling vehicle stability is also provided.

Claims

1. A method of controlling stability of a vehicle comprising the steps of:

determining rotational speed of at least inside and outside drive wheels that are rotatably-controlled by respective hydraulically-actuated clutches; and

if the rotational speed of the inside and outside drive wheel is not substantially the same, applying fluid pressure from a hydraulic pump that is selectively and variably directed by a valve to the hydraulically-actuated clutches for adjusting or vectoring torque of one of or both the inside and outside drive wheels.

2. The method according to claim 1 further comprising the step of

if the rotational speed of the inside and outside drive wheels is substantially the same, applying no fluid pressure to the hydraulically-actuated clutches to maintain the hydraulically-actuated clutches in an open state that allows full slip of outputs that are respectively connected to the inside and outside wheels.

3. The method according to claim 1 wherein the applying step includes selectively or variably applying fluid pressure to one of the hydraulically-actuated clutches that is operatively connected to the outside drive wheel when the vehicle is in an under-steer situation.

4. The method according to claim 1 wherein the applying step includes selectively or variably applying fluid pressure to one of the hydraulically-actuated clutches that is operatively connected to the inside drive wheel when the vehicle is in an over-steer situation.

5. The method according to claim 1 wherein the applying step includes selectively or variably applying fluid pressure to both hydraulically-actuated clutches to lock rotation of the inside and outside drive wheels with the rotational movement of half-shafts that are driven by an input.