Hydraulic support element

Abstract

This disclosure relates to a hydraulic support element for a switchable rocker arm of a valve train of an internal combustion engine. The hydraulic support element includes a cup-shaped cylinder, within which a hollow piston is arranged in an axially displaceable manner. The piston includes a filter cartridge which is in the form of a hollow body and can be charged from the outside with pressurized oil and an interior space of which is connected to an outlet opening of the contact head. An interior space of the piston has two pressurized oil chambers, including a first pressurized oil chamber above the piston head and connected to a first pressurized oil feed, and a second pressurized oil chamber formed under the contact head and connected to a second pressurized oil feed. The filter cartridge is tubular and located in the second pressurized oil chamber.

Claims

1. A hydraulic support element for a switchable finger follower of a valve train of an internal combustion engine, the hydraulic support element comprising: a cup-shaped cylinder with a base arranged at a cylinder end, a hollow piston arranged in an axially movable manner within the cup-shaped cylinder, the hollow piston having: a piston head facing the base, a contact head arranged at a free end of the hollow piston, the contact head configured to support the finger follower, and an interior space fluidly connected to an outlet opening formed in the contact head, a filter cartridge formed as a tubular body, the filter cartridge configured to be charged from outside the filter cartridge with pressurized oil and an interior space of the filter cartridge fluidly connected to the outlet opening of the contact head and, the interior space of the hollow piston having a first pressurized oil chamber and a second pressurized oil chamber separated from each other by a partition element, the first pressurized oil chamber arranged above the piston head and fluidly connected to a first pressurized oil feed, and the second pressurized oil chamber formed under the contact head and fluidly connected to a second pressurized oil feed, and a first end of the filter cartridge sealingly located on the partition element in the second pressurized oil chamber, and a second end of the filter cartridge fluidly connected to the outlet opening of the contact head.

2. The hydraulic support element as claimed in claim 1, wherein the filter cartridge has a sealing collar at each of its two ends, a first sealing collar associated with the first end of the filter cartridge is sealingly located on the partition element and a second sealing collar associated with the second end of the filter cartridge is sealingly located against an inner wall of the contact head.

3. The hydraulic support element as claimed in claim 1, wherein the filter cartridge is mounted by means of the first end on a tubular protuberance of the partition element, the protuberance being directed toward the second pressurized oil chamber, and the second end of the filter cartridge carries a sealing sleeve, which is sealingly located against an inner wall of the contact head.

4. The hydraulic support element as claimed in claim 1, wherein the partition element has a restriction orifice which connects the first pressurized oil chamber to the second pressurized oil chamber.

5. The hydraulic support element of claim 4, wherein the restriction orifice is arranged between the second pressurized oil feed and the contact head.

6. The hydraulic support element as claimed in claim 1, wherein the first and second pressurized oil feeds each comprise: a feed opening formed in a wall of the cylinder, the feed opening configured to be connected to a pressurized oil line, at least one inlet opening formed in a wall of the hollow piston, and an annular space formed between the wall of the cylinder and the wall of the hollow piston, the annular space having an axial extent that connects the feed opening and the at least one inlet opening.

7. A hydraulic support element for a switchable finger follower of a valve train of an internal combustion engine, the hydraulic support element comprising: a cup-shaped cylinder with a base arranged at a cylinder end, a hollow piston arranged in an axially movable manner within the cup-shaped cylinder, the hollow piston having: a piston head facing the base, a contact head arranged at a free end of the hollow piston, the contact head configured to support the finger follower, and an interior space fluidly connected to an outlet opening formed in the contact head, a filter cartridge formed as a tubular body disposed within the interior space, the filter cartridge configured to be charged from outside the filter cartridge with pressurized oil and an interior space of the filter cartridge fluidly connected to the outlet opening of the contact head and, the interior space of the hollow piston having two pressurized oil chambers separated from each other by a partition element, a first end of the filter cartridge sealingly located on the partition element, and a second end of the filter cartridge fluidly connected to the outlet opening of the contact head.

8. The hydraulic support element of claim 7, wherein the filter cartridge is configured to be charged from outside the filter cartridge with pressurized oil from one of the two pressurized oil chambers formed between the contact head and the partition element.

9. The hydraulic support element as claimed in claim 7, wherein the partition element has a restriction orifice which connects the two pressurized oil chambers.

10. A hydraulic support element for a switchable finger follower of a valve train of an internal combustion engine, the hydraulic support element comprising: a cup-shaped cylinder with a base arranged at a cylinder end, a hollow piston arranged to move axially within the cup-shaped cylinder, the hollow piston having: a piston head facing the base, a first pressurized oil chamber formed between the piston head and base, a contact head arranged at a free end of the hollow piston, the contact head configured to support the finger follower, and an interior space having a second pressurized oil chamber and a third pressurized oil chamber, the second pressurized oil chamber arranged between the first and third pressurized oil chambers, and a filter cartridge formed as a tubular body disposed within the third pressurized oil chamber, the filter cartridge configured to be charged from outside the filter cartridge with pressurized oil and an interior space of the filter cartridge fluidly connected to an outlet opening of the contact head.

11. The hydraulic support element of claim 10, wherein a length of the tubular body is greater than a diameter of the tubular body.

12. The hydraulic support element of claim 10, further comprising a check valve arranged between the first and second pressurized oil chambers.

13. The hydraulic support element of claim 12, wherein the first, second, and third pressurized oil chambers are fluidly connected with each other when the check valve is in an open state.

14. The hydraulic support element of claim 10, further comprising a first oil feed fluidly connected to: i) the second pressurized oil chamber; and, ii) the first pressurized oil chamber via the second pressurized oil chamber and a check valve, the check valve arranged between the first and second pressurized oil chambers.

15. The hydraulic support element of claim 14, further comprising a second oil feed fluidly connected to the third pressurized oil chamber.

16. The hydraulic support element of claim 15, wherein the second oil feed is arranged between the first oil feed and the outlet opening of the contact head.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure is explained by means of illustrative embodiments. For this purpose, drawings are attached to the description. In the drawings:

(2) FIG. 1 shows a partial longitudinal section through a double-flow hydraulic support element having the features of the disclosure, and

(3) FIG. 2 shows a support element as per FIG. 1 in a different embodiment.

DETAILED DESCRIPTION

(4) The hydraulic support element 2 illustrated in FIG. 1 has an outer cup-shaped cylinder 4 and a hollow piston 6, which can be moved axially in said cylinder. At its cylinder end, which is at the bottom in FIG. 1, the piston 6 has a piston head 8, on which a downward-opening, spring-loaded check valve 10 formed by a ball and an associated ball seat is arranged. A compression spring 14 resting against the piston head 8, on the one hand, and against the base 12 of the cylinder 4, on the other hand, loads the piston 6 in an upward direction, wherein the travel of the piston 6 in the upward direction is limited by a stop ring 16 arranged on the inside of the cylinder 4.

(5) Formed on that end of the piston 6 which faces away from the piston head 8 is a contact head 18, which is intended to support a switchable finger follower (not illustrated). An outlet opening 20, which is fluidly connected to an interior space 7 of the piston 6, is formed in the contact head 18.

(6) The interior 7 of the piston 6 is divided by means of a partition wall element 22 into a first pressurized oil chamber 24 associated with the piston head 8 and a second pressurized oil chamber 26 associated with the contact head 18. The two pressurized oil chambers 24, 26 each have dedicated pressurized oil feeds. For this purpose, there are two feed openings 28, 30, each connectable to pressurized oil supply lines (not illustrated), in the wall of the cylinder 4, wherein the first feed opening 28 is fluidly connected via an associated annular space 32, which is formed between the cylindrical wall of the cylinder 4 and the cylindrical wall of the piston 6, to an inlet opening 34, which is formed in the wall of the piston 6 and leads to the first pressurized oil chamber 24. The second feed opening 30 is fluidly connected via an associated annular space 36 to an inlet opening 38 leading to the second pressurized oil chamber 26.

(7) When the support element 2 is subjected to axial loading, the piston 6 is held in a rigid manner by the pressurized oil present in the high-pressure chamber 40 situated below the piston head 8 and thus forms a rigid support for a finger follower. When the load is relieved, the piston 6 is loaded upward by the compression spring 14 and can draw additional oil into the high-pressure chamber 40 via the check valve 10 and thus compensate any lash with respect to the finger follower.

(8) Arranged in the second pressurized oil chamber 26, which is associated with the contact head 18, is a tubular filter cartridge 42, the first axial end of which, which faces the partition element 22, is sealingly located on said partition wall 22 and the second, open end of which is fluidly connected to the outlet opening 20 of the contact head 18. For this purpose, the filter cartridge 42 has a sealing collar 44, 46 at each of its two ends, wherein the first sealing collar 44, that associated with the first end, is sealingly located on the partition element 22 and the second sealing collar 46, that associated with the second end, is sealingly located against the lateral inner wall of the contact head 18. During operation, the pressurized oil in the second pressurized oil chamber 26 acts on the filter cartridge 42 from radially on the outside to radially on the inside, and the filtered pressurized oil can emerge through the outlet opening 20 for the purpose of lubricating the contact surfaces and switching the switchable finger follower.

(9) FIG. 2 shows a hydraulic support element 48, which is of substantially identical construction to the support element 2 in FIG. 1. It differs from the latter only in the geometry of the partition element 50 and of the filter cartridge 52 interacting with said element, and therefore the construction and operation of the actual support element does not need to be described in detail again.

(10) Toward the second pressurized oil chamber 54, the partition element 50 shown in FIG. 2 has a tubular protuberance 56, on which the tubular filter cartridge 52 is mounted by means of its lower end in FIG. 2, thereby closing this end. The upper end of the filter cartridge 52 carries a sealing sleeve 58, which is sealingly located against the lateral inner wall of the contact head 60. Accordingly, the open upper end of the filter cartridge 52 is fluidly connected to the outlet opening 62 of the contact head 60, thereby providing lubrication of the contact surfaces between the contact head 60 and the finger follower and allowing the switching of said follower to be performed by means of filtered pressurized oil.

(11) In both illustrative embodiments illustrated, the partition element 22, 50 is provided with a restriction orifice 47, 64, which fluidly connects the first pressurized oil chamber 24, 53 to the second pressurized oil chamber 26, 54 and allows pressure equalization.

REFERENCE CHARACTERS

(12) 2 hydraulic support element 4 cylinder 6 piston 7 interior space 8 piston head 10 check valve 12 base of cylinder 14 compression spring 16 stop ring 18 contact head 20 outlet opening 22 partition element 24 first pressurized oil chamber 26 second pressurized oil chamber 28 feed opening 30 feed opening 32 annular space 34 inlet opening 36 annular space 38 inlet opening 40 high-pressure chamber 42 filter cartridge 44 sealing collar 46 sealing collar 47 restriction orifice 48 hydraulic support element 50 partition element 52 filter cartridge 53 first pressurized oil chamber 54 second pressurized oil chamber 56 tubular protuberance 58 sealing sleeve 60 contact head 62 outlet opening 64 restriction orifice