OUTER HOUSING FOR A HYDRAULIC LASH ADJUSTER WITH TAPERED OIL FEED ANNULUS
A hydraulic lash adjuster is provided. The hydraulic lash adjuster includes an outer housing having an annular body with an open first axial end, a closed second axial end, a radially inner wall defining an axial bore, and a radially outer wall. The radially outer wall includes a first annular groove located adjacent to the first axial end, and a second annular groove located adjacent to the second axial end. A first port is located in the first annular groove, and a second port is located in the second annular groove. A radially outer surface of the first annular groove tapers radially inwardly between a first axial end and a second axial end.
Latest SCHAEFFLER TECHNOLOGIES GMBH & CO. KG Patents:
- Camshaft adjuster and separating sleeve for a camshaft adjuster
- TORSIONAL-VIBRATION DAMPING SYSTEM FOR A VEHICLE DRIVE TRAIN
- Method for producing a tribologically distressed laminate, a laminate and use of an organometallic compound for producing a functional layer of the laminate
- Roller for a pendulum mass of a centrifugal force pendulum
- Electric axle with a two gear transmission
The following documents are incorporated herein by reference as if fully set forth: U.S. Provisional Application No. 61/880,296, filed Sep. 20, 2013.
FIELD OF INVENTIONThis application is generally related to a hydraulic lash adjuster and is more particularly related to an outer housing for a hydraulic lash adjuster.
BACKGROUNDHydraulic lash adjusters are used in valve trains of internal combustion engines to accommodate lash and to control valve lift modes. Internal combustion engines include cylinder heads in which the lash adjusters are arranged to have a plurality of hydraulic fluid galleries that feed pressurized hydraulic fluid to ports defined in an outer housing of the hydraulic lash adjuster. A plunger is arranged within a bore of the outer housing and is axially displaceable to perform the hydraulic lash adjustment as well as optionally a switching function to provide a partial or zero lift opening of the associated valve. When the switching function is provided, one of the ports feeds hydraulic fluid into a chamber of the plunger that directs the hydraulic fluid to an open-ended nose portion and actuates a switching function of the rocker arm or finger lever assembly between first and second valve lift modes. A significant amount of pressure loss occurs when the hydraulic fluid flows from the hydraulic fluid gallery of the cylinder head to a space defined between the cylinder head and an outer surface of the outer housing. The pressure loss increases the amount of time required to execute the switching function of the rocker arm assembly and reduces engine performance. It is desirable to minimize the amount of time required to perform the switching function and to minimize the pressure loss when hydraulic fluid travels from the cylinder head gallery to the ports on the outer housing of the adjuster.
SUMMARYAn outer housing for a hydraulic lash adjuster with a tapered oil feed annulus is provided. The outer housing is positionable within a cylinder head of an engine which includes a plurality of hydraulic fluid galleries. The outer housing includes an annular body with an open first axial end, a closed second axial end, a radially inner wall defining an axial bore, and a radially outer wall. The radially outer wall includes a first annular groove located adjacent to the first axial end, and a first port is located in the first annular groove. A radially outer surface of the first annular groove tapers radially inwardly between a first axial end and a second axial end. The first port is located adjacent to the second axial end of the first annular groove. The tapered outer surface of the first annular groove reduces resistance of hydraulic fluid flowing from a hydraulic fluid gallery in the cylinder head into the first port. The tapered outer surface directs hydraulic fluid towards the second axial end of the first annular groove and the first port.
In another embodiment, the radially outer surface of the first annular groove tapers radially inwardly between the first axial end and a center-point of the first port.
In one preferred embodiment the outer housing includes a second annular groove located adjacent to the second axial end, and a second port is located in the second annular groove.
Preferred arrangements with one or more features of the invention are described below and in the claims.
The foregoing Summary as well as the following Detailed Description will be best understood when read in conjunction with the appended drawings. In the Drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “inner,” “outer,” “inwardly,” and “outwardly” refer to directions towards and away from the parts referenced in the drawings. 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, derivates thereof, and words of similar import.
A first port 18 is located in the first annular groove 14, and a second port 20 is located in the second annular groove 16. Each port 18, 20 extends through the radially inner and outer walls 10, 12 to the axial bore 11 of the outer housing 2. The ports 18, 20 are preferably circular and the diameter of the ports can vary depending on the application. The ports 18, 20 are each aligned with at least one hydraulic fluid gallery 9 defined in the cylinder head 5 of the engine. During operation, hydraulic fluid flows from the galleries 9 defined in the cylinder head 5 to the ports 18, 20 and eventually to respective axial ends of the plunger 4. In a preferred embodiment, the first port 18 is used for the switching function of the rocker arm assembly 3 and the second port 20 is used for lash adjustment. The radially inner wall 10 can include annular grooves at the location of the first and second ports 18, 20.
In a preferred embodiment shown in
In another embodiment shown in
Having thus described various embodiments of the present hydraulic lash adjuster 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 above, could be made in the apparatus without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.
LOG TO REFERENCE NUMBERS1. Hydraulic Lash Adjuster
2. Outer Housing
3. Rocker Arm Assembly
4. Plunger
5. Cylinder Head
6. First Axial End of Outer Housing
7. Bore of Cylinder Head
8. Second Axial End of Outer Housing
9. Hydraulic Fluid Galleries
10. Radially Inner Wall
11. Axial Bore
12. Radially Outer Wall
14. First Annular Groove
16. Second Annular Groove
18. First Port
20. Second Port
22. Radially Outer Surface of the First Annular Groove
24. First Axial End of the First Annular Groove
26. Second Axial End of First Annular Groove
28. Center-point of First Port
Claims
1. A hydraulic lash adjuster comprising:
- an outer housing having an annular body with an open first axial end, a closed second axial end, a radially inner wall defining an axial bore, and a radially outer wall, the radially outer wall includes a first annular groove located adjacent to the first axial end;
- a first port located in the first annular groove; and
- a radially outer surface of the first annular groove tapers radially inwardly between a first axial end and a second axial end.
2. The hydraulic lash adjuster of claim 1, the outer housing further comprising a second annular groove located adjacent to the second axial end, and a second port located in the second annular groove.
3. The hydraulic lash adjuster of claim 1, wherein the first port is located adjacent to the second axial end of the first annular groove.
4. The hydraulic lash adjuster of claim 1, wherein the radially outer surface of the first annular groove tapers radially inwardly by approximately 3 degrees between the first axial end and the second axial end.
5. The hydraulic lash adjuster of claim 1, wherein a thickness of the annular body at the first axial end of the first annular groove is greater than a thickness of the annular body at the second axial end of the first annular body.
6. The hydraulic lash adjuster of claim 1, wherein a thickness of the annular body decreases from approximately 1.25 mm at the first axial end of the first annular groove to approximately 0.6 mm at the second axial end of the first annular groove.
7. The hydraulic lash adjuster of claim 1, wherein the first annular groove has an axial length of approximately 6.0 mm.
8. The hydraulic lash adjuster of claim 1, wherein the first annular groove has a radial depth of approximately 0.45 mm.
9. A hydraulic lash adjuster comprising:
- an outer housing having an annular body with an open first axial end, a closed second axial end, a radially inner wall defining an axial bore, and a radially outer wall, the radially outer wall includes a first annular groove located adjacent to the first axial end;
- a first port located in the first annular groove; and
- a radially outer surface of the first annular groove tapers radially inwardly between a first axial end and a center-point of the first port.
10. The hydraulic lash adjuster of claim 9, the outer housing further comprising a second annular groove located adjacent to the second axial end, and a second port located in the second annular groove.
11. The hydraulic lash adjuster of claim 9, wherein the first port is located adjacent to a second axial end of the first annular groove.
12. The hydraulic lash adjuster of claim 9, wherein a thickness of the annular body decreases from approximately 1.25 mm at the first axial end of the first annular groove to approximately 0.65 mm at the center-point of the first port.
13. A valve train for an internal combustion engine comprising:
- a cylinder head including a bore and a plurality of hydraulic fluid galleries;
- an outer housing positioned in the bore of the cylinder head and having an annular body with an open first axial end, a closed second axial end, a radially inner wall defining an axial bore, and a radially outer wall, the radially outer wall includes a first annular groove located adjacent to the first axial end;
- a first port located in the first annular groove and in communication with a first hydraulic fluid gallery of the plurality of hydraulic fluid galleries;
- a radially outer surface of the first groove tapers radially inwardly between a first axial end and a second axial end;
- a plunger that is axially displaceable within the axial bore of the annular body; and
- a rocker arm assembly in abutment with the plunger that is actuatable between a first and second valve lift mode via a hydraulic fluid feed from the plunger.
14. The valve train of claim 13, the outer housing further comprising a second annular groove located adjacent to the second axial end, and a second port located in the second annular groove and in communication with a second hydraulic fluid gallery of the plurality of hydraulic fluid galleries.
Type: Application
Filed: Sep 16, 2014
Publication Date: Mar 26, 2015
Applicant: SCHAEFFLER TECHNOLOGIES GMBH & CO. KG (Herzogenaurach)
Inventor: Matthew Evans (Warren, MI)
Application Number: 14/487,777
International Classification: F01L 1/24 (20060101); F01L 13/00 (20060101);