Patent · US Active

Hydraulical shifting device for an automatic transmission

US8944232B2 · kind B2 · utility

6Cited by

1References

20Claims

0Family size

Assignee

ZF FRIEDRICHSHAFEN AG · DE

Inventors

Thilo Schmidt · Meckenbeuren, DE
Markus Herrmann · Scheidegg, DE
Hans-Joachim Martin · Kreßbronn, DE

Key dates

Filing date	Jan 4, 2013
Grant date	Feb 3, 2015
Priority date	—
Expiry date	May 9, 2033

Classification

Technology area (CPC F)Mechanical Engineering; Lighting; Heating
CPC primaryF16H63/3483
WIPO fieldMechanical elements
WIPO sectorMechanical engineering

Abstract

A hydraulic shifting device for an automatic transmission for engaging and disengaging a parking lock. The shifting device comprises a parking lock cylinder (203) for actuating the parking lock, and a parking lock valve (201) which, for hydraulic control of the parking lock cylinder (203), can be switched to at least first and second shift positions. In this case the hydraulic shifting device comprises a further parking lock valve (202), and the two parking lock valves (201, 202) and the parking lock cylinder (203) are designed and connected with one another in such manner that the parking lock can only be disengaged by pressurizing the parking lock cylinder (203) if the two parking lock valves (201, 202) are each switched to a particular shift position.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.