Hydraulic Control Device for an Automatic Transmission

Patent metadata

Field	Value
Publication number	US-2016265657-A1
Application number	US-201415029822-A
Country	US
Kind code	A1
Filing date	Sep 17, 2014
Priority date	Oct 17, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

In an operating state of the automatic transmission in which a transmission stage is engaged and no gearshift occurs, the stop valve ( 1 ) is in a first shifting position, in which at least the torque-transferring shift element (K) is sealed tight against the rest of the hydraulic system by means of the allocated stop valve ( 1 ), such that the actuating pressure (p_K) enclosed in the shift element (K) remains essentially constant or does not decrease. It is thereby provided that the stop valve ( 1 ) is formed and arranged in the hydraulic system in such a manner that it is held in the first shifting position by the force of a barrier pressure (p_S) generated by the pump (P), and, upon a standstill of the pump (P) or falling below a certain value of the pressure generated by the pump (P), the stop valve ( 1 ) is automatically displaceable at least through the action of the trapped shift element pressure (p_K) into a second shifting position, in which the respective shift element (K) is connected to the rest of the hydraulic system and the shift element (K) is open.

First claim

1 . Hydraulic control device for an automatic transmission comprising multiple frictional-locking shift elements (K), the hydraulic control device comprising at least one stop valve ( 1 ) allocated to a shift element and multiple pressure adjusting devices allocated to a shift element and barrier pressure adjusting devices allocated to the stop valve ( 1 ), whereas, for the presentation of transmission stage, at least two shift elements for transferring a torque by means of the pressurization through a hydraulic actuating pressure (p_K) generated by a pump (P) and adjusted in the respective pressure adjusting device are kept closed, whereas, at least in one operating state of the automatic transmission in which a transmission stage is engaged and no gearshift occurs, the stop valve ( 1 ) is in a first shifting position, in which at least the torque-transferring shift element (K) is sealed tight at the respective pressure adjusting device by means of the allocated stop valve ( 1 ), such that the actuating pressure (p_K) enclosed in the shift element (K) remains essentially constant or does not decrease, characterized in that at least one stop valve ( 1 ) is formed and arranged in the hydraulic system in such a manner that it is held in the first shifting position by the force of a barrier pressure (p_S) generated by the pump (P), and, upon a standstill of the pump (P) or falling below a certain value of the pressure generated by the pump (P), and thus the barrier pressure (p_S), the stop valve ( 1 ) is automatically displaceable at least through the action of the trapped shift element pressure (p_K) into a second shifting position, in which the respective shift element (K) is connected to the respective pressure adjusting device.

2 - 19 . (canceled)

Assignees

• Zahnradfabrik Friedrichshafen
• Zahnradfabrik Friedrichshafen

Inventors

• Herrmann Markus
• Schmidt Thilo
• Allgaier Bernd

Classifications

• F16H2061/026

  On-off solenoid valve · CPC title

• F16H61/0251

  Elements specially adapted for electric control units, e.g. valves for converting electrical signals to fluid signals · CPC title

• F16H61/0206

  Layout of electro-hydraulic control circuits, e.g. arrangement of valves · CPC title

• F16H61/0267

  Layout of hydraulic control circuits, e.g. arrangement of valves · CPC title

• F16H61/0276 Primary

  Elements specially adapted for hydraulic control units, e.g. valves · CPC title