Patent Application
20180283224
The present invention relates to a hydraulic support element for a valve drive of an internal combustion engine, comprising a housing with a central bore and a piston that is provided in that bore, with the piston having a bottom to define a first pressure chamber and further comprising a second pressure chamber between a bottom face of the housing and the bottom of the piston, further comprising a valve that is provided between the first pressure chamber and the second pressure chamber.
Such a hydraulic support element is disclosed in the U.S. Pat. No. 8,813,705 B2. This Patent describes a hydraulic support element having a housing, a pressure piston, a high pressure chamber for a hydraulic pressure medium extending between a bottom face of the pressure piston and a bottom of the housing, wherein the housing includes a passage for the hydraulic pressure medium, which communicates radially inwardly with an aperture in the pressure piston, wherein the pressure piston includes a deflecting sheath for the hydraulic pressure medium, tightly contacting the pressure piston at the interior jacket axially below the aperture and extending to the proximity of a head of the pressure piston, wherein a rising line for the hydraulic pressure medium is formed between the deflecting sheath and the interior jacket, which starts at the aperture and leads in the area of the head into a reservoir inside the deflecting sheath directly in front of the return valve and with the deflecting sheath having at least one perforation axially above its contact.
One object of the invention is to provide a hydraulic support element comprising a housing with a central bore and a bottom face that is provided on one axial end of the housing, a piston that is arranged in the bore of the housing, the piston is connected to a bottom closure so as to define a first pressure chamber and a second pressure chamber is defined between the bottom face and the bottom closure, a valve provided between the first pressure chamber and the second pressure chamber to regulate a fluid connection between the pressure chambers, and a seal formed between the piston and the bottom closure with the bottom closure being affixed to the piston in a detachable manner. Thus, the manufacturing of the piston is highly simplified and thus less expensive. The bottom closure can be manufactured separately from the piston. The design of the piston is also less complicated and thus easier to produce.
In another embodiment the piston comprises a first piston part and a second piston part and at least one of the piston parts is connected to the bottom closure. Preferably, the piston is a hollow cylindrical shape. This way, the piston has a less complex design and can be produced more easily and cheaply.
In another embodiment, the piston has a groove for the fixation of the bottom closure, and a retaining element is inserted in the groove. This way, the bottom closure is fixed to the piston in an axial direction. Preferably, the retaining element is ring-shaped and is snappable into the groove of the piston in order to fix the bottom closure.
In another embodiment, the second piston part includes a first portion and a second portion and the first portion has a smaller diameter than the second portion. This “chimney”-design of the piston increases a medium reserve volume in the first pressure chamber. Preferably, the second piston part further comprises at least one feed opening for a fluid connection. Preferably, the feed opening is located in an area between the first portion and the second portion of the second piston part.
In another embodiment, a pipe is integrated in the piston such that at least one part of the pipe is connected to at least one of the piston parts.
In another embodiment, the valve comprises a ball for opening and closing a fluid connection between the first pressure chamber and the second pressure chamber.
Preferably, the second piston part has at least one lubricant hole in a medial portion. It is preferred that the lubricant hole is in the first portion of the second piston part.
Additionally, in another embodiment, the second piston part is closed at one end face with a piston bottom. Preferably, the piston bottom further comprises a deaeration hole.
In another embodiment, the inner surface of the second piston part has a step formed by an increased inner diameter between the smallest inner diameter of the second piston part and the groove.
The foregoing Summary and the following detailed description will be better understood when read in conjunction with the appended drawings, which illustrate a preferred embodiment of the invention. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from the parts referenced in the drawings. “Axially” refers to a direction along the axis of a shaft. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, or c, or combinations thereof. The terminology includes the words specifically noted above, derivatives thereof and words of similar import.
Hydraulic support element 10 is shown in
The second piston part 22 has a first portion 22a and a second portion 22b, whereby the second portion 22b has a greater diameter than the first portion 22a. Both portions 22a, 22b are, preferably integrally, connected to each other by a shoulder. This shoulder provides at least one feed opening 24 to allow a flow of hydraulic medium from the outside of the hydraulic support element 10 to the inner side of the piston 20. Preferably, there are provided more than one, especially four feed openings 24 in the area between the first and the second portion 22a, 22b of the second piston part 22, as shown in
On the other side of the second piston part 22 there is provided a bottom closure 23. In a preferred embodiment, the bottom closure 23 is ring-shaped and has a central opening. The bottom closure 23 is affixed to the piston 20 in a detachable manner. This allows to manufacture the piston 20, especially the second piston part 22, with a very simple process and thus cost-effective.
For the fixation of the bottom closure 23 to the piston 20 there is provided a step on the inner diameter of the second piston part 22. This step has an increased diameter in comparison to the medial portion of the second piston, part 22. To prevent leakage there is assembled a seal 26, especially in form of an o-ring, to the step of the inner side of the second piston part 22. After that, the bottom closure 23 is assembled and is affixed with a retaining element 27. This retaining element 27 is preferably ring-shaped and is snappable to the inner side of the second piston part 22 in a groove 22e. The retaining element 27 is in direct contact with the bottom closure 23 and secures it in an axial direction. The step and the seal 26 on the other axial side of the bottom closure 23 define a second limit stop for the bottom closure 23. Thus, it is securely fixed to the piston 20.
The seal 26 seals the first pressure chamber 40 that is defined with the inner volume of the piston 20, from a second pressure chamber 50. The second pressure chamber is defined between the bottom closure 23 and the bottom face 13 of the housing 11.
The hydraulic support element further comprises a valve 30 including an axial movable ball 31 for the opening and closing of a fluid connection between the first and the second pressure chamber 40, 50. Therefore, the valve further comprises a pot-shaped cap 32. Within the cap 32 there is provided a spring 33 that urges the ball 31 against the bottom closure 23 to open and/or close the central opening of the bottom closure 23 and thus allow a fluid connection between the first and second pressure chamber 40, 50. The cap 32 is held in position between the bottom closure 23 and the retaining element 27 due to the connection between the retaining ring 27 and the piston 20. On the outer side of the cap 32, there is further provided a return spring 34 that urges the cap 32 towards the bottom closure 23.
Preferably, the pressure in the first pressure chamber 40 is lower than the pressure in the second pressure chamber 50. Thus, the valve ball 31 is normally in direct contact with the bottom closure 23 (and closes the central opening of the bottom closure 23). The valve 30 is therefore normally closed.
Having thus described the present invention in detail, it is to be appreciated and will be apparent to those skilled in the art that many physical changes, only a few of which are exemplified in the detailed description of the invention, could be made without altering the inventive concepts and principles embodied therein. It is also to be appreciated that numerous embodiments incorporating only part of the preferred embodiment are possible which do not alter, with respect to those parts, the inventive concepts and principles embodied therein. The present embodiment and optional configurations are therefore to be considered in all respects as exemplary and/or illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all alternate embodiments and changes to this embodiment which come within the meaning and range of equivalency of said claims are therefore to be embraced therein.
