Shifting arrangement for two clutches for the shifting between a single-axle standard drive and a two-axle all-wheel drive for a motor vehicle having two drivable vehicle axles

US4722414A · kind A · utility

Assignee

• Daimler-Benz AG · DE

Inventors

• Arno Rohringer · Ditzingen, DE
• Manfred Link · Nuremberg, DE
• Jurgen Frank · Bad Nauheim, DE

Key dates

• Filing date: Jan 13, 1987
• Grant date: Feb 2, 1988
• Expiry date: Jan 13, 2007

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60W30/18145
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A shifting arrangement for the shifting between a single-axle standard drive and an all-wheel drive having a first clutch for the locking of a central differential gear and a second clutch for the connecting and disconnecting of one vehicle axle actuated by first and second pressure medium control element respectively against the force of a spring having first and second shift valve respectively controlled by an electronic control unit, to either supply working pressure or relieve from pressure respective control elements. The improvement including a hydraulic identifying valve for bringing the control elements into a mutual interaction. The identifying valve operates, as a function of the working pressure of at least one of the control elements and exclusively during the simultaneous controlling of both shift valves, in such a way that the clutch torque at both clutches increases and decreases approximately to the same extent. As a result, when shifting into a shift step with a balanced all-wheel drive from standard drive, a shifting can first take place for a short time into an intermediate step with a longitudinally locked all-wheel drive for securing the driving stability.