Hydraulic Actuating Device for a positive-locking shifing element of a transmission

Patent metadata

Field	Value
Publication number	US-2016169381-A1
Application number	US-201514970604-A
Country	US
Kind code	A1
Filing date	Dec 16, 2015
Priority date	Dec 16, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A hydraulic actuating device is provided for a positive-locking shifting element of a transmission with a cylinder, in which a piston is arranged in a manner displaceable between a first end position and a second end position. The piston is a stepped piston and, with the cylinder, bounds an additional pressure chamber, which is connected to a first pressure chamber and/or a second pressure chamber through at least one hydraulic line. The volume of the additional pressure chamber decreases during an actuating movement of the piston in the direction of the first end position and increases during an actuating movement of the piston in the direction of the second end position. The degree of locking of the connection between the additional pressure chamber and the first pressure chamber and/or the second pressure chamber increases through the cylinder from a defined actuating path of the piston prior to reaching the first end position up to the first end position.

First claim

1 - 5 : (canceled)

6 . A hydraulic actuating device for a positive-locking shifting element of a transmission, comprising:
a cylinder; a piston arranged in displaceable manner in the cylinder between a first end position that corresponds to a closed operating state of the shifting element, and a second end position that corresponds to an open operating state of the shifting element; the piston displaceable by applying actuating pressure at a first active surface of a first pressure chamber bounded by the cylinder in a direction of the first end position; the piston also displaceable by applying actuating pressure at a second active surface of a second pressure chamber bounded by the cylinder in a direction of the second end position; the piston designed as a stepped piston that, with the cylinder, bounds an additional pressure chamber that is connected to one or both of the first pressure chamber and the second pressure chamber through at least one hydraulic line defined across an actuating path of the piston, wherein a volume of the additional pressure chamber decreases during an actuating movement of the piston towards the first end position and increases during an actuating movement of the piston towards the second end position; wherein the hydraulic line connection between the additional pressure chamber and the first pressure chamber or the second pressure chamber in the first end position of the piston is at least partially locked by the cylinder, and a degree of such locking by the cylinder increases as the piston moves towards the first end position.

7 . The hydraulic actuating device according to claim 6 , wherein the additional pressure chamber is bounded by the cylinder and comprises an additional active surface, an area of the second active surface being larger than an area of the additional active surface.

8 . The hydraulic actuating device according to claim 6 , wherein the hydraulic line connects the second pressure chamber to the additional pressure chamber, the hydraulic line including a first line section extending in an axial direction into the piston and a second line section leading from the first line section into the additional pressure chamber, the first line section having a flow cross-section that is larger than a flow cross-section of the second line section.

9 . The hydraulic actuating device according to claim 6 , wherein the hydraulic line connects the first pressure chamber to the additional pressure chamber, the hydraulic line including a first section extending essentially in an axial direction into the piston and a second line section leading from the first line section into the additional pressure chamber.

10 . The hydraulic actuating device according to claim 7 , wherein a sum of the areas of the second active surface and the additional active surface is equal to the area of the first active surface.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Novak Rainer

Classifications

• F16H2063/303

  the friction member is actuated and released by applying pressure to different fluid chambers · CPC title

• F16H63/3023

  the final output mechanisms comprising elements moved by fluid pressure (band brake actuating mechanisms F16H63/3003) · CPC title

• F15B15/224

  having a piston which closes off fluid outlets in the cylinder bore by its own movement · CPC title

• F15B15/204

  Control means for piston speed or actuating force without external control, e.g. control valve inside the piston (F15B11/02, F15B15/22 take precedence) · CPC title

• F15B15/149

  Fluid interconnections, e.g. fluid connectors, passages · CPC title