DE102012211859A1 - Hydraulic support element for valve train of internal combustion engine, has pressure piston comprising inlet for hydraulic agent within housing, and closure element arranged in piston and regulating flow of agent from inlet into reservoir - Google Patents

Abstract

The element (1) has a cylindrical case (2) in which a hollow pressure piston (3) is axial slidingly arranged with a reservoir (5) for oil as hydraulic agent and connected with a high pressure space (8) of the housing over a non-return valve (9). The pressure piston comprises a lateral inlet (6) for the hydraulic agent within the housing. A closure element (11) is arranged in the pressure piston and regulates flow of the hydraulic agent from the inlet into the reservoir. The closure element is provided with a lateral flow aperture for the hydraulic agent by a cylindrical small tube.

Description

Field of the invention

The invention relates to a hydraulic support element for the valve train of an internal combustion engine, with a cylindrical housing in which a hollow pressure piston with a reservoir for oil as a hydraulic fluid arranged axially displaceable and connected via a check valve with a high pressure chamber of the housing, wherein the pressure piston within the housing having a lateral inlet for the hydraulic means.

Background of the invention

Internal combustion engines with cam follower valve drives use hydraulic support elements for valve clearance compensation. In such a support element has the disadvantage that the hydraulic fluid from the reservoir of the pressure piston after switching off the internal combustion engine gradually expires to a level below the lateral inlet, if against a constructive action was not taken. If then in the support member, a part of the oil used as hydraulic fluid after stopping the engine to the acting as oil supply hole inlet of the pressure piston, the stored in the reservoir of the pressure piston lower hydraulic amount is not sufficient and it can after a renewed engine start by sucking Air in the high-pressure chamber of the housing to Ventiltriebsgeräuschen come.

To solve this problem is in the document DE 10 2005 022 456 A1 proposed for a support element of the type mentioned for transporting the hydraulic fluid within the pressure piston, a deflecting element in the form of a thin tube, which is fixed with one end in the inlet and extending in the storage space in the direction of the head of the pressure piston, which, as the drawing shows, located outside the housing.

Also from the pamphlets DE 10 2006 007 375 A1 and DE 10 2006 007 376 A1 Embodiments of support elements are known in which in each case within the pressure piston as deflection a pipe construction to prevent the leakage of hydraulic fluid is installed. However, the prior art designs not only have the disadvantage of being structurally complex, but they also do not allow to keep the hydraulic fluid completely in the pressure piston after switching off the internal combustion engine.

Summary of the invention

The invention has for its object to provide a support element, in which the outflow of hydraulic fluid from the reservoir of the pressure piston is completely prevented and thus the hydraulic function of the support element is guaranteed for a rattle-free operation at engine start due to a complete sealing of the reservoir.

This object is achieved in that in the pressure piston a flow of the hydraulic fluid from the inlet into the storage space regulating closure member is arranged. This can be formed by a cylindrical tube with a lateral flow opening for the hydraulic medium, in which an axially displaceable, the flow opening occlusive or releasing piston is arranged.

The piston can be acted upon axially by a return spring acting as a compression spring in the direction of its position closing the flow opening.

When the internal combustion engine is switched off, the piston can be pressed by the return spring against an annular inner shoulder of the tube in its position closing the flow opening. In this case, the return spring force via the piston causes a sealing of the storage space of the pressure piston, so that hydraulic fluid can not escape.

When the internal combustion engine is switched on, the piston may be displaced from the pressure force of the hydraulic medium which exceeds the spring force of the return spring into its position which releases the flow opening. Then, during engine operation, the oil pressure acts against the piston and overcomes the force of the return spring.

Short description of the drawing

An embodiment of the invention is illustrated in the drawing and will be described in more detail below. Show it

1 a support element with a closure member whose flow opening is closed to the storage space of the pressure piston, partially in the side view and partially in longitudinal section;

2 the support element according to 1 , but in the open position of the passage opening of the closure member;

3 the region of the support element with the closure member according to 2 in an enlarged view, in longitudinal section.

Detailed description of the drawing

A hydraulic support element 1 for a valve train of an internal combustion engine consists of a cylindrical housing 2 and a pressure piston 3 which is on a part of its length in the housing 2 is inserted longitudinally displaceable. The support element 1 can be installed as a valve clearance compensation element in a receiving bore of the cylinder head of the internal combustion engine. His pressure piston 3 points to the outside of the housing 2 end a head 4 on, on which a lever-like cam follower can be mounted pivotably.

The pressure piston 3 is hollow and has a storage space 5 for oil as hydraulic means, which via a lateral inlet 6 of the pressure piston 3 can be filled. When the internal combustion engine is switched on, the hydraulic fluid can be used as pressure oil through a lateral filling opening 7 in the case 2 and from there through the inlet 6 of the pressure piston 3 in the pantry 5 reach.

Between the pantry 5 and a high pressure room 8th of the housing 2 is a check valve 9 arranged. The high pressure room 8th located at the axial end of the housing 2 , which of the inserted pressure piston 3 turned away. There is the housing 2 and thus the high pressure room 8th with a floor 10 closed at the front.

According to the invention is in the pressure piston 3 a flow of hydraulic fluid from the inlet 6 in the pantry 5 regulating closure member 11 arranged. This consists of one in the inlet 6 of the pressure piston 3 with one end pressed in small tube 12 which is inside the storeroom 5 a radial flow opening 13 having. In the tube 12 is at his from the inlet 6 facing away closed end a return spring 14 arranged as a compression spring on one in the tube 12 axially displaceable piston 15 acts.

When the internal combustion engine is switched off, the return spring shifts 14 the piston 15 towards the inlet 6 until the piston 15 on an annular shoulder 16 rests within the tube 12 in the area of the inlet 6 is trained. In this position, the piston closes 15 the flow opening 13 of the tube 12 , This will work with the piston 15 the interior of the tube 12 on the one hand, opposite the housing 2 and, on the other hand, opposite the pantry 5 completely sealed and in the pantry 5 stored hydraulic fluid is completely held there. It can not make it through the flow opening 13 still over the inlet 6 escape. The entry of air into the storage room 5 can not. When switching on the internal combustion engine is thus the entire amount of hydraulic fluid available in the pantry 5 is stored and needed for the valve clearance compensation. In this way a rattle-free operation at engine start is guaranteed.

When the internal combustion engine is pressurized oil as hydraulic fluid through the filling opening 7 in the case 2 promoted and lies there in the inlet 6 of the pressure piston 3 on the piston 15 of the tube 12 at. Because of the pressure oil on the piston 15 acting compressive force is greater than that of this opposing force of the return spring 14 , the piston needs 15 away from the paragraph 16 on to the end of the tube 12 move, which from the inlet 6 turned away. In this case, the return spring 14 pressed together. In this position gives the piston 15 the flow opening 13 of the tube 12 free, leaving a loss amount of hydraulic oil from the inlet 6 in the tube 12 and from there via the flow opening 13 in the pantry 5 can flow in.

LIST OF REFERENCE NUMBERS

1

supporting

2

casing

3

pressure piston

4

head

5

pantry

6

inlet

7

fill opening

8th

High-pressure chamber

9

check valve

10

ground

11

closure member

12

tube

13

Flow opening

14

Return spring

15

piston

16

paragraph

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005022456 A1 [0003]
• DE 102006007375 A1 [0004]
• DE 102006007376 A1 [0004]

Claims (6)

Hydraulic support element ( 1 ) for the valve train of an internal combustion engine, with a cylindrical housing ( 2 ), in which a hollow pressure piston ( 3 ) with a storage room ( 5 ) arranged axially displaceably for oil as a hydraulic medium and via a check valve ( 9 ) with a high-pressure chamber ( 8th ) of the housing ( 2 ), wherein the pressure piston ( 3 ) within the housing ( 2 ) a lateral inlet ( 6 ) for the hydraulic means, characterized in that in the pressure piston ( 3 ) a flow of the hydraulic fluid from the inlet ( 6 ) in the storage room ( 5 ) regulating closure member ( 11 ) is arranged. Supporting element according to claim 1, characterized in that the closure member ( 11 ) from a cylindrical tube ( 12 ) with a lateral flow opening ( 13 ) is formed for the hydraulic means, in which an axially displaceable, the flow opening ( 13 ) occluding or releasing piston ( 15 ) is arranged. Supporting element according to claim 2, characterized in that the piston ( 15 ) of acting as a compression spring return spring ( 14 ) is acted upon axially. Supporting element according to Claim 3, characterized in that, when the internal combustion engine is switched off, the piston ( 15 ) in its the flow opening ( 13 ) closing position of the return spring ( 14 ) to an annular inner shoulder ( 16 ) of the tube ( 12 ) is pressed. Supporting element according to claim 3, characterized in that when the internal combustion engine is switched on the piston ( 15 ) of which the spring force of the return spring ( 14 ) exceeding the pressure force of the hydraulic fluid in its the flow opening ( 13 ) releasing position has been postponed. Supporting element according to claim 1, characterized in that the closure member of a cylindrical tube ( 12 ) with a lateral flow opening ( 13 ) is formed for the hydraulic medium, in which a the flow opening ( 13 ) closing or releasing ball is arranged, which in the axial direction of the tube ( 12 ) of acting as a compression spring return spring ( 14 ) is acted upon.

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