Length-adjustable connecting rod

Patent metadata

Field	Value
Publication number	US-10294859-B2
Application number	US-201415028638-A
Country	US
Kind code	B2
Filing date	Oct 13, 2014
Priority date	Oct 18, 2013
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

The invention relates to a length-adjustable connecting rod (1) for a reciprocating-piston machine, in particular for an internal combustion engine, comprising at least one first rod part (6) having a small connecting rod eye (2) and a second rod part (9) having a large connecting rod eye (4), which two rod parts can be moved in relation to each other and/or in each other in a telescopic manner, wherein the second rod part forms a guiding cylinder (8) and the first rod part forms a piston element (7) that can be longitudinally displaced in the guiding cylinder, wherein a first high-pressure chamber (10) is spanned between the second rod part and the piston element on the side of the piston element facing the large connecting rod eye, into which first high-pressure chamber at least one first oil channel (20) leads, in which in particular a first check valve (21) opening in the direction of the first high-pressure chamber is arranged, wherein at least a first return channel (22) extends from the first high-pressure chamber, an outflow cross-section of which return channel can be closed by a control valve (13) in a first position and can be opened by the control valve in a second position, wherein the control valve preferably has a control piston (15) that can be axially displaced in an accommodating bore (14) of the second rod part of the connecting rod, which control piston in particular can be moved into the first position by means of a return spring (16) and can be moved into the second position against the force of the return spring by means of an actuating force. In order to be able to change the compression ratio as simply possible, the piston element according to the invention is designed as a piston that is operative at both ends.

First claim

The invention claimed is:

1. A length-adjustable connecting rod for a reciprocating-piston machine, the length-adjustable connecting rod comprising:
at least one first rod part having a small connecting rod eye and a second rod part having a large connecting rod eye, which first and second rod parts can be moved in relation to each other and/or in each other in a telescopic manner, wherein the second rod part forms a guiding cylinder and the first rod part forms a piston element that can be longitudinally displaced in the guiding cylinder, wherein a first high-pressure chamber is positioned between an end face of the guiding cylinder and a first end face of the piston element facing the large connecting rod eye, into which first high-pressure chamber at least one first oil channel leads, wherein the at least one first oil channel comprises a first check valve that opens in a direction of the first high-pressure chamber, wherein at least a first return channel extends from the first high-pressure chamber, wherein an outflow cross section of said first return channel can be closed by a control valve in a first position and can be opened by the control valve in a second position, wherein when said control valve is in the first position said first return channel is blocked by the control valve such that oil suctioned into the first pressure chamber cannot escape from said first high-pressure chamber,
a second high-pressure chamber positioned between a holding part, which is fixedly connected to the second rod part, and a second end face of the piston element facing towards the small rod eye, wherein at least one second oil channel leads into the second high-pressure chamber,
wherein the piston element is designed as a double acting piston, and wherein the control valve comprises a control piston and actuation of the control piston is performed hydraulically by oil pressure of the reciprocating-piston machine or electromagnetically.

2. The connecting rod according to claim 1 , wherein the first position of the control valve is associated with an extended position of the first rod part and the second position of the control valve is associated with a retracted position of the first rod part.

3. The connecting rod according to claim 2 , wherein the first rod part can be hydraulically locked relative to the second rod part both in the extended position and also in the retracted position.

4. The connecting rod according to claim 1 , wherein a second check valve is arranged in the at least one second oil channel, and the second check valve opens in the direction of the second high-pressure chamber.

5. The connecting rod according to claim 1 , wherein the at least one second oil channel and/or a second return channel is/are arranged outside a longitudinal center plane of the connecting rod, which encloses the longitudinal axis of the connecting rod.

6. The connecting rod according to claim 1 , wherein a feed cross section to the at least one second oil channel can be closed by the control valve in the first position and can be opened in the second position.

7. The connecting rod according to claim 1 , wherein at least one second return channel extends from the second high-pressure chamber, wherein the outflow cross section of said at least one second return channel can be closed by the control valve in the second position and can be opened in the first position, wherein when said control valve is in the second position said at least one second return channel is blocked by the control valve such that oil suctioned into the second pressure chamber cannot escape from said second high-pressure chamber.

8. The connecting rod according to claim 7 , wherein only the first and second return channels can be controlled by the control valve.

9. The connecting rod according to claim 1 , wherein at least one return flow throttle is arranged in a feed line to the control valve.

10. The connecting rod according to claim 1 , wherein the holding part is formed by a replaceable stop sleeve, which protrudes into the guiding cylinder.

11. The connecting rod according to claim 10 , wherein the stop sleeve is screwed together with the second rod part.

12. The connecting rod according to claim 1 , wherein a feed cross section to the first oil channel can be closed by the control valve in the second position and can be opened in the first position of the control valve.

13. The connecting rod according to claim 1 , wherein the actuation of the control piston is performed against a force of a return spring.

14. The connecting rod according to claim 1 , wherein the control piston consists of ferromagnetic material or has a permanent magnet element configured to interact with an induction coil arranged in a crankcase of a reciprocating-piston machine.

15. The connecting rod according to claim 1 , wherein the control piston can be locked in at least one position by at least one locking element.

16. The connecting rod according to claim 15 , wherein the locking element is formed by a spring-loaded pressure part.

17. The connecting rod according to claim 15 , wherein the locking element has a spring-loaded pressure body, which acts on the control piston transversely to a movement direction thereof.

18. The connecting rod according to claim 1 , wherein the control piston can be axially displaced in an accommodating bore of the second rod part of the connecting rod.

19. The connecting rod according to claim 1 , wherein the piston element is designed as a stepped piston.

20. The connecting rod according to claim 1 , wherein the control piston can be moved into a first position by means of a return spring and can be moved into a second position against a force of the return spring by means of an actuating force.

Assignees

• Avl List Gmbh

Inventors

• Melde-Tuczai Helmut
• Lichtenegger Stefan
• Hoedl Bernhard

Classifications

• F16C7/06 Primary

  Adjustable connecting-rods · CPC title

• F02B75/045 Primary

  by means of a variable connecting rod length · CPC title

• F02F3/00

  Pistons · CPC title

• F02F1/00

  Cylinders; Cylinder heads · CPC title

• F16C7/04

  with elastic intermediate part of fluid cushion · CPC title