Active torque bias system and controls

Details Active torque bias system and controls Active torque bias system and controls

2002-05-16

2003-11-11

Wright, Dirk (Department: 3681)

Planetary gear transmission systems or components

Electric or magnetic drive or control

Plural power paths

C180S249000

Reexamination Certificate

active

06645108

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATIONS
Not applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
BACKGROUND OF THE INVENTION
This invention relates in general to the apportionment of torque between the axles of an automotive vehicle and, more particularly, to a torque biasing unit and a control system for it.
While most four real wheel automotive vehicles operate with the engine torque delivered to only the front wheels or the rear wheels, some vehicles, particularly the more sophisticated ones, are equipped with all wheel drive systems. In the typical vehicle so equipped, the engine torque is delivered to all four wheels all the time, but usually one set of wheels constitutes the primary driving wheels in that they are connected directly to the vehicle transmission, while the other set, known as the secondary wheels, is connected indirectly through a mechanism which accommodates for variations in velocity between the primary and secondary wheels. For example, when a vehicle negotiates a turn, the primary wheels follow arcs having radii different from the radii of the arcs followed by the secondary wheels, and as a consequence the primary and secondary wheels rotate at different angular velocities.
Some of these mechanisms have the capacity to apportion the engine torque between the primary and secondary wheels, with the apportionment depending on driving conditions. For example, a vehicle will accelerate best with most of the torque—and tractive effort—delivered through the rear wheels. On the other hand, when a turn is negotiated, it is best to transfer some of the torque to the front wheels. Certainly, when the primary wheels lose traction, more torque should be transferred to the secondary wheels. However, the mechanisms for apportioning torque are cumbersome and difficult to control. The typical mechanism involves a clutch having friction surfaces along which slippage occurs. This slippage is just one of multiple parameters involved in the control of the clutch.
BRIEF SUMMARY OF THE INVENTION
The present invention resides in a transfer unit for apportioning torque between the primary and secondary axles of an automotive vehicle and a control strategy for the transfer unit. The transfer unit contains a torque bias coupling for extracting the torque for the secondary axle, and that coupling includes a clutch and a planetary gear set organized such that the extracted torque takes two paths through it—one a clutch path in which slippage can occur and the other a mechanical path in which no slippage occurs. The slippage in the clutch of the clutch path dissipates power, which manifests itself as heat, and the controller monitors the power dissipated to insure that it does not exceed prescribed limits for the conditions under which the automotive vehicle operates. The invention also resides in the process embodied in the operation of the transfer unit and controller.


REFERENCES:
patent: 4417641 (1983-11-01), Kageyama
patent: 4440042 (1984-04-01), Holdeman
patent: 4606446 (1986-08-01), Watanabe
patent: 4656889 (1987-04-01), Mueller
patent: 4766973 (1988-08-01), Kashihara et al.
patent: 4803628 (1989-02-01), Hayashi et al.
patent: 4805721 (1989-02-01), Takahashi et al.
patent: 4860612 (1989-08-01), Dick et al.
patent: 4871049 (1989-10-01), Okita
patent: 4989686 (1991-02-01), Miller et al.
patent: 5002147 (1991-03-01), Tezuka et al.
patent: 5090510 (1992-02-01), Watanabe et al.
patent: 5208755 (1993-05-01), Tezuka
patent: 5497333 (1996-03-01), Sasaki
patent: 5733222 (1998-03-01), Kawahara et al.
patent: 5980415 (1999-11-01), Showalter
patent: 6142905 (2000-11-01), Brown et al.
patent: 6158303 (2000-12-01), Shiraishi et al.

Affiliated with

Also associated with

Rating

Active torque bias system and controls does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Active torque bias system and controls, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Active torque bias system and controls will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3120274