US 4,747,643 AGranted

Motor vehicle having two driven axles and brake system

AssigneeSteyr-Daimler-Puch AG

InventorHeribert Lanzer

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Abstract

A motor vehicle comprises two driven axles (5, 8), which are interconnected by an interaxle coupling (10) for transmitting a torque only when the halves of the coupling (10) rotate at different speeds and by a speed-changing transmission (9) connected in series with the coupling (10). A brake system (12 to 15) is provided for braking the wheels of both axles (5, 8). In order to ensure that the wheels of the driven rear axle (8) will not block before the wheels of the driven front axle (5), a pressure-setting controller (17) is adapted to control a brake pressure regulator (16) associated with the driven rear axle (8) and is responsive to a reversal of the direction in which torque is transmitted to and from the driven rear axle (8). During a transmission of torque from the driven rear axle (8) to the driven front axle (5), the pressure-setting controller (17) substantially reduces in dependence on the value of the torque being transmitted the pressure which is applied to brake the wheels of the driven rear axle (8) relative to the pressure which is applied to brake the wheels of the driven front axle (5).

Claims7

Dependent claims

In a motor vehicle comprising

a driven front axle having front wheels,
a driven rear axle having rear wheels,
an interaxle power train interconnecting said front and rear axles and comprising a speed-changing transmission and in series with said transmission a liquid friction coupling having two coupling members and adapted to transmit torque only when said two coupling members rotate at different speeds, and
a brake system for applying pressure to brake said front and rear wheels, which brake system comprises a brake pressure regulator for controlling the pressure applied to brake said rear wheels,
the improvement residing in that
a pressure-setting controller is provided, which is responsive to a reversal of the direction of torque transmission between said interaxle coupling and said rear axle and to the value of torque transmitted from the rear axle to said interaxle coupling and is adapted to operate said brake pressure regulator in dependence on said value of torque said brake pressure regulator so as to effect a substantial reduction of the pressure applied to brake said rear wheels relative to the pressure applied to brake said front wheels only during a transmission of torque from said rear wheels to said interaxle coupling.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/042,355Filed 24 Apr 1987
Priority: AT A1140/8629 Apr 1986
Granted: 31 May 1988
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

B60T 8/349
Having a fluid pressure regulator responsive to a speed condition: systems adapted to control a set of axles, e.g. tandem axles
B60T 8/26
Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of…:…
B60T 8/322
Deceleration: systems specially adapted for vehicles driven by more than one axle, e.g. Four Wheel-Drive vehicles
Y10S 303/06
Fluid-pressure and analogous brake systems: axle differential control