Pressure medium-actuated control device of an automated step-by-step variable speed transmission

US8167105B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Markus Herrmann · Scheidegg, DE
• Thomas John · Augsburg, DE

Key dates

• Filing date: Oct 1, 2007
• Grant date: May 1, 2012
• Expiry date: Mar 25, 2029

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2061/1264
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A pressure medium-actuated control device of an automated step-by-step variable speed transmission. The device having a control valve for controlling an actively engaged disconnectable type clutch which is disposed along a power flow path between a motor and a transmission input shaft, and a self-retaining valve located in the pressure supply of the clutch control valve for a rotational speed-dependent emergency actuation of the disconnectable type clutch. An electrical switch-off actuator is connected to the self-retaining valve such that the valve piston, of the self-retaining valve, can be moved into an idle position to lock the pressure supply of the clutch control valve in a powered state of the switch-off actuator, and into an operating position determined by the applied control pressures in the power-off state of the switch-off actuator.