Control device of a rotating shifting element of an automatic transmission for engine start-stop operation

US8839930B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventor

• Horst Rogner · Markdorf, DE

Key dates

• Filing date: Nov 4, 2011
• Grant date: Sep 23, 2014
• Expiry date: Dec 26, 2032

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2312/14
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A device for controlling a rotating shifting element of an automatic transmission for a start/stop operation. The shifting element is actuated by an axially moving piston which is biased, in a disengaging direction, by a spring and biased, in an engaging direction, by hydraulic pressure supplied to a pressure space. At least one spring-loaded latch, which is able to move in the radial direction, is arranged in the pressure space. The spring-loaded latch, when the combustion engine is operating, rotates with the piston and acts upon the piston such that if the engine stops, the previously engaged shifting element is locked by spring force and, as the pressure decreases, the shifting element disengages, at most only slightly, and when the engine is re-started, the locking action is again released by centrifugal force, in opposition to the spring force, so that the piston remains engaged during the hydraulic pressure build-up in the pressure chamber.