Force transmission device

Patent metadata

Field	Value
Publication number	US-10718237-B2
Application number	US-201816013324-A
Country	US
Kind code	B2
Filing date	Jun 20, 2018
Priority date	Jun 21, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

The present disclosure relates to a force transmission device for connection between a camshaft and a gas exchange valve including a main body with a receptacle which extends along a longitudinal axis. The force transmission device has an actuating piston which is provided in the receptacle such that it can move between a first position and a second position, and a contact body for actuating the gas exchange valve and in operative connection with the actuating piston. The force transmission device has a first blocking piston which is provided in the receptacle such that it can move in a radial direction with respect to the longitudinal axis between a third position, in which the first blocking piston blocks the actuating piston in the first position, and a fourth position, in which the first blocking piston releases a movement of the actuating piston between the first position and the second position.

First claim

I claim:

1. A force transmission device for producing an operative connection between a camshaft and a gas exchange valve of an internal combustion engine, the force transmission device comprising:
a main body with a receptacle which extends along a longitudinal axis (A);
an actuating piston provided in the receptacle such that the actuating piston is configured to move back and forth between a first position and a second position along the longitudinal axis (A);
a contact body configured to actuate the gas exchange valve and is in operative connection with the actuating piston such that a movement of the actuating piston along the longitudinal axis (A) leads to a movement of the contact body along the longitudinal axis (A) so as to change a valve stroke of the gas exchange valve;
a first blocking piston provided in a control fluid space of the actuating piston and in the receptacle such that the first blocking piston is configured to move back and forth in a radial direction with respect to the longitudinal axis (A) between a third position, in which the first blocking piston blocks the actuating piston in the first position, and a fourth position, in which the first blocking piston releases a movement of the actuating piston between the first position and the second position; and
a damping chamber which is configured to be filled with a control fluid and which is emptied during movement of the actuating piston from the first position to the second position so as to damp the movement of the actuating piston, wherein the damping chamber is fluidically connected to the control fluid space of the actuating piston via at least one duct.

2. The force transmission device according to claim 1 , wherein the force transmission device is a rocker lever or finger-type rocker.

3. The force transmission device according to claim 1 , wherein the gas exchange valve is an inlet valve.

4. The force transmission device according to claim 1 , wherein the receptacle in the main body is cylindrical.

5. The force transmission device according to claim 1 , further comprising:
a second blocking piston situated opposite the first blocking piston, is provided in the receptacle such that the second blocking piston is configured to move back and forth in a radial direction with respect to the longitudinal axis between a fifth position, in which the second blocking piston blocks the actuating piston in the first position, and a sixth position, in which the second blocking piston releases a movement of the actuating piston between the first position and the second position.

6. The force transmission device according to claim 5 , wherein:
the actuating piston is elastically prestressed in a direction towards the first position; or the first blocking piston is elastically prestressed in a direction towards the third position; or
the second blocking piston is elastically prestressed in a direction to the fifth position; or
the first blocking piston and the second blocking piston are elastically supported with respect to one another.

7. The force transmission device according to claim 1 , wherein the blocking of the actuating piston in the first position, and the release of the movement of the actuating piston between the first position and the second position, allows a two-stage valve stroke variability for producing two different valve stroke profiles of the gas exchange valve.

8. The force transmission device according to claim 1 , wherein the receptacle has a groove, wherein:
the first blocking piston is engaged in the groove in the third position, blocking movement of the first blocking piston along the longitudinal axis (A), and the first blocking piston is disengaged from the groove in the fourth position, releasing the movement of the first blocking piston along the longitudinal axis (A); or
a second blocking piston engaged in the groove in a fifth position, blocking movement of the second blocking piston along the longitudinal axis (A), and the second blocking piston is disengaged from the groove in a sixth position, releasing the movement of the second blocking piston along the longitudinal axis (A).

9. The force transmission device according to claim 8 , wherein the groove is a cylindrical circumferential groove around the longitudinal axis (A).

10. The force transmission device according to the claim 1 , wherein, when the actuating piston is acted upon via the contact body in a direction along the longitudinal axis (A) to the second position, the actuating piston executes a lost motion from the first position to the second position by which the valve stroke of the gas exchange valve is reduced when the first blocking piston or a second blocking piston releases the movement of the actuating piston between the first position and the second position.

11. The force transmission device according to claim 1 , wherein:
the first blocking piston is acted upon hydraulically by supplying the control fluid, so as to move from the third position to the fourth position; or
a second blocking piston is acted upon hydraulically by supplying the control fluid, so as to move from a fifth position to a sixth position.

12. The force transmission device according to claim 1 , wherein the first blocking piston or a second blocking piston is guided in or on the actuating piston in the radial direction with respect to the longitudinal axis (A).

13. The force transmission device according to claim 1 , wherein,
only when there is a substantially force-free operative connection between the camshaft and the gas exchange valve via the force transmission device, a movement of the first blocking piston or of a second blocking piston is released in the radial direction with respect to the longitudinal axis (A); or,
when the first blocking piston or second blocking piston is acted upon via the contact body in a direction along the longitudinal axis (A) to the second position, a movement of the first blocking piston from the third position into the fourth position or of the second blocking piston from a fifth position into a sixth position is blocked by a static friction on account of a valve opening force between the first blocking piston or the second blocking piston and a groove.

14. The force transmission device according to claim 1 , further comprising a control fluid supply and a separately provided lubricating fluid supply.

15. The force transmission device according to claim 1 , wherein:
the damping chamber is emptied during movement of the actuating piston from the first position to the second position while generating a turbulent flow, wherein the damping chamber is delimited by the actuating piston and the receptacle.

16. The force transmission device according to claim 1 , further comprising:
an anti-rotation safeguard which blocks a rotation of the first blocking piston or a second blocking piston.

17. The force transmission device according claim 1 , further comprising:
a valve play compensation device arranged on the contact body in operative connection with the actuating piston and the contact body so as to compensate for a valve play.

18. The force transmission device according to claim 17 , wherein one or more of the actuating piston, the first blocking piston, and a second blocking piston is hydraulic, or the valve play compensation device is hydraulic or mechanical.

19. The force transmission device according to claim 1 , further comprising a camshaft phase adjuster for the camshaft, the camshaft phase adjuster configured to produce a Miller control time

Assignees

• Man Truck & Bus Ag

Inventors

• Bogdanski Peter

Classifications

• F01L13/0015

  for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque · CPC title

• F01L1/267

  with means for varying the timing or the lift of the valves · CPC title

• F01L1/2416

  by means of a hydraulic adjusting device attached to an articulated rocker · CPC title

• F01L1/181 Primary

  Centre pivot rocking arms · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title