Actuator for an electrohydraulic gas-exchange valve train of a combustion engine

Patent metadata

Field	Value
Publication number	US-9920664-B2
Application number	US-201515113957-A
Country	US
Kind code	B2
Filing date	Jan 20, 2015
Priority date	Feb 4, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An actuator for an electrohydraulic gas exchange valve train of a combustion engine is provided. The actuator has an actuator housing which can be mounted on the combustion engine with a borehole, a hydraulic piston, which is mounted therein such that it can carry out a reciprocating movement, for actuating the gas exchange valve and an axial stop which, when the actuator housing is in the unmounted state relative to the combustion engine, limits the piston stroke out of the borehole to a mounting stroke (T). This mounting stroke is smaller than a maximum operating stroke (L) with which the hydraulic piston actuates the gas exchange valve, the piston stroke being only temporarily limited to the mounting stroke by the axial stop and no longer being limited to the mounting stroke once the actuator is in operation.

First claim

The invention claimed is:

1. An actuator for an electrohydraulic gas-exchange valve train of a combustion engine, comprising an actuator housing that is mountable on the combustion engine with a borehole, a hydraulic piston movably supported for a piston stroke motion in the borehole for actuating the gas-exchange valve, and an axial stop that limits the piston stroke motion out of the borehole to a mounting stroke (T) in an unmounted state of the actuator housing on the combustion engine, the mounting stroke (T) is less than a maximum operating stroke (L) with which the hydraulic piston actuates the gas-exchange valve, and the limiting of the piston stroke motion to the mounting stroke (T) by the axial stop is cancelled only temporarily and after the actuator has been put into operation.

2. The actuator according to claim 1 , wherein the hydraulic piston displaces a position of the axial stop relative to the borehole or to the hydraulic piston due to operating pressurization such that the limitation of the piston stroke to the mounting stroke (T) is cancelled.

3. The actuator according to claim 2 , wherein the hydraulic piston comprises a hydraulic valve play compensation element with a piston shaft and a compensation housing that surrounds a gas-exchange-valve-side end section of the piston shaft and actuates the gas-exchange valve, a piston-side part of the displaceable axial stop is formed by a piston-side projection extending radially outwards from an outer circumference of the compensation housing and a borehole-side part of the displaceable axial stop is formed by a borehole-side projection extending radially inward at a front or in an inner circumference of the borehole and the piston-side and borehole-side projections overlap radially.

4. The actuator according to claim 3 , wherein the piston-side projection is formed by a wire ring held in an outer circumference groove of the compensation housing.

5. The actuator according to claim 3 , wherein the limitation of the piston stroke to the mounting stroke (T) is cancelled by displacing the borehole-side projection relative to the borehole.

6. The actuator according to claim 5 , wherein the borehole-side projection is formed by a ring that is held on the inner circumference of the borehole by a clamping part and consequently displaces the piston-side projection of the operationally pressurized hydraulic piston in an axial direction.

7. The actuator according to claim 6 , wherein the ring is constructed as a wire ring that consequently displaces initially the piston-side projection of the operationally pressurized hydraulic piston in the axial direction and then spreads out while cancelling a radial overlap with the piston-side projection in an inner circumferential groove of the borehole.

8. The actuator according to claim 5 , wherein the borehole-side projection is formed by a ring that is held on an outer circumference of the actuator housing by a clamping part and consequently displaces the piston-side projection of the operationally pressurized hydraulic piston in an axial direction.

9. The actuator according to claim 5 , wherein the actuator comprises another axial stop that limits the piston stroke out of the borehole to a disassembly stroke (R) in a mounted state of the actuator housing on the combustion engine, and said disassembly stroke is equal to or greater than the maximum operating stroke (L).

10. The actuator according to claim 9 , wherein a sleeve is held on an outer circumference of the compensation housing that includes a ring for connection to the actuator housing, the ring latches into one of a first axial position and a second axial position on an outer circumference of the actuator housing, and the ring limits the piston stroke out of the borehole in the first axial position to the mounting stroke (T) and in the second axial position to the disassembly stroke (R).

Assignees

• Schaeffler Technologies Ag

Inventors

• Itoafa Calin Petru
• Schafer Sandra
• Kremer Thomas

Classifications

• F01L1/46

  Component parts, details, or accessories, not provided for in preceding subgroups · CPC title

• F01L1/25 Primary

  between cam and valve stem · CPC title

• F01L2303/00

  Manufacturing of components used in valve arrangements · CPC title

• F01L2201/00

  Electronic control systems; Apparatus or methods therefor · CPC title

• F01L2103/00

  Mechanical Engineering · mapped topic