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Publication numberUS3704696 A
Publication typeGrant
Publication dateDec 5, 1972
Filing dateMar 8, 1971
Priority dateMar 8, 1971
Also published asDE2211139A1
Publication numberUS 3704696 A, US 3704696A, US-A-3704696, US3704696 A, US3704696A
InventorsAbell Roy F Jr
Original AssigneeEaton Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydraulic valve lifter
US 3704696 A
Abstract
A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine includes a body member, a plunger member located at least partially within the body member, and a face member located at least partially within the body member and having a cam engageable surface thereon. A fluid reservoir is located between the face member and the body member and a pressure chamber is disposed between the plunger member and the body member for taking up lash in the valve gear. A leakage passageway is provided between the face member and the body member and provides for the flow of lubricating fluid from the reservoir to the cam engaging surface of the face member to thereby provide for lubrication of the cam engaging surface and the cam. The leakage passageway also provides for air leakage from the lifter to prevent air lockup of the lifter.
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United States Patent Abell, Jr.

HYDRAULIC VALVE LIFTER [4 Dec. 5, 1972 Primary Examiner-Laurence M. Goodridge I Assistant Examiner-Cort Flint Attorney-Teagno & Toddy [5 7] ABSTRACT A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine includes a body member, a plunger member located at least partially within the body member, and a face member located at least partially within the body member and having a cam engageable surface thereon. A fluid reservoir is located between the face member and the body member and a pressure chamber is disposed between the plunger member and the body member for taking up lash in the valve gear. A leakage passageway is provided between the face member and the body member and provides for the flow of lubricating fluid from the reservoir to the cam engaging surface of the face member to thereby provide for lubrication of the cam engaging surface and the cam. The leakage passageway also provides for air leakage from the lifter to prevent air lockup of the lifter.

10 Claims, 3 Drawing Figures PATENTEDnEc 5 I972 SHEEI 1 OF 2 ATTORNEYJ FIGI HYDRAULIC VALVE LIFTER The present invention relates to a hydraulic valve lifter for use in a direct acting overhead cam engine and more particularly to a hydraulic valve lifter having a leakage passageway which provides for lubricant flow from the lifter to the cam engaging surface thereof and for air flow from the lifter to prevent air lockup thereof.

During operation of an engine utilizing a direct acting overhead camshaft valve gear and a hydraulic valve lifter for compensating for lash in the valve gear, problems occur when air in the lubrication system becomes internally trapped within the valve lifter. The air trapped in the valve lifter causes air lockup which effects malfunction of the valve lifter. This .problem of air lockup has not been solved by the prior art lifters. Moreover, during operation of an engine in which the camshaft acts directly on the valve lifter it is necessary to provide for lubrication between the camshaft and the valve lifter. Many known hydraulic valve lifters do not provide for adequate lubrication between the direct acting overhead camshaft and the valve lifter, consequently, wear and failure of the camshaft or valve lifter occurs. One known method of providing lubrication between the camshaft and the valve gear utilizes expensive boring of the camshaft with intersecting drilled holes in each cam lobe for directing lubrication to the lifter and camshaft. This method, used in the majority of production direct acting overhead cam engines is undesirable due to the high cost involved in drilling the camshaft and cam lobes.

Accordingly, an object of the present invention is to provide a new and improved hydraulic valve lifter for use in a direct acting overhead camshaft valve gear having a leakage passageway from the valve lifter for providing for air flow from the valve lifter and/or lubricant flow from the valve lifter to effect lubrication of the cam member and the face surface of the valve lifter against which the cam member acts.

Another object of the present invention is to provide a new and improved hydraulic valve lifter for use in a direct acting overhead camshaft valve gear including a body member, a plunger member, a face member having a cam engageable surface thereon, a fluid reservoir at least partially defined by the face member and a leakage passageway from the fluid reservoir providing for lubricant flow from the reservoir to the cam engaging surface of the face member and providing for air flow from the reservoir to prevent air lockup of the lifter.

Still another object of the present invention is to provide a new and improved hydraulic valve lifter as defined in the next preceding paragraphwherein the leakage passageway is defined between the body member and the face member.

A further object of the present invention'is to provide a new and improved hydraulic valve lifter including a body member, a plunger member located at least partially within the body member, a face member slip fitted in the body member, a fluid reservoir at least partially defined by the face member, a leakage passageway providing for lubricant flow from the reservoir to the outer surface of the face member and providing for air flow from the reservoir to prevent air lockup of the lifter and wherein the leakage passageway is defined between an outer peripheral surface of the face member and an inner surface of the body member.

A still further object of the present invention is to provide a new and improved hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine including a body member, a plunger member located at least partially within the body member, a fluid reservoir located within the body member, a cam engageable outer surface for engaging with the cam of the engine and imparting movement to the body member in response to rotation of the cam, and a leakage passageway providing for the flow of lubricating fluid from the reservoir to the cam engageable with the surface and the flow of air from the reservoir to thereby prevent, lockup of the lifter.

Further objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an illustration'of a hydraulic valve lifter constructed in accordance with the present invention, and utilized in a direct acting overhead camshaft valve gear for operating a valve of an overhead cam engine; FIG. 2-is, a sectional view, taken approximately along the'line 22 of FIG. 1, illustrating the internal structure of the hydraulicvalve lifter; and

FIG. 3 is a view similar to the view of FIG. 2 illustrating the pressure chamber in an expanded condition.

The present invention relates to a hydraulic valve lifter or lash adjuster for use in a direct acting overhead camshaft valve gear, having a leakage passageway providing for lubricant flow from the reservoir of the lifter to the cam engaging surface of the valve lifter. The leakage passageway also provides for the flow of air from the valve lifter to prevent lockup thereof. The valve lifter includes a body member, a plunger member located within the body I member and cooperating therewith to define a pressure chamber. A face member is disposed on the upper portion of the body member and has the cam engaging surface disposed on the external portion thereof. The face member cooperates with the body member to define the fluid reservoir and a passageway is provided from the reservoir to the pressure chamber. The face member is slip fitted into the top portion of the body member and the outer periphery of the face member cooperates with an inner surface of the body member to define the leakage passageway which provides fluid communication between the reservoir and the external cam engaging surface of the face member. The leakage passageway enables lubricant to flow from the reservoir to lubricate the cam engaging surface of the face member and provides for the flow of air from the reservoir outwardly therefrom. The clearance between the outer periphery of the face member and the inner surface of the body member is controlled to regulate the lubricant flow from the reservoir.

Although a hydraulic lifter or lash adjuster 10 constructed in accordance with the present invention can be used in many different types of engines, the hydraulic lifter 10 is illustrated in FIG. 1 in a direct acting overhead camshaft valve gear 12 of an engine 14 having an overhead cam 16. The valve gear 12 is actuated by rotation of the cam 16 to operate a valve 20 (shown in FIG. 1 in a closed position) to control the flow of gases from a combustion chamber 22 in a known manner.

Means, more fully described hereinbelow, is provided to enable lubricant to flow from internal portions of the lifter 10 to effect lubrication of the cam 16. The means also provides for the flow of air from the lifter 10 to prevent lockup of the lifter due to air becoming trappedtherein.

The cam 16 is mounted on a camshaft 24 and rotates therewith. Upon rotation of the cam 16 in a clockwise direction, a leading ramp 36 of an actuating or nose portion 38 of the cam 16 engages a face member 26 of the valve lifter 10 to push the valve lifter 10 and the valve 20 in a downwardly direction as viewed in FIG. 1 to open the valve 20. Continued rotation of the cam16 brings a trailing ramp 40 of the cam 16 into engagement with the face member 26 of the valve lifter l and the valve 20 then moves toward the illustrated closed position under the influence of a valve spring44. After a base circle portion 28 of the cam 16 engages the face member 26, the valve 20 is held closed by the valve spring 44 until the leading ramp 36 of the cam 16 is again brought into engagement with the face member 26.

The hydraulic lifter adjusts the valve gear 12 to maintain a predetermined relationship i.e.,' zero lash, between the cam 16 and the valve even though the dimensions of the valve 20 and cam 16 may vary due to wear, thermal effects and other reasons. To this end, the hydraulic lifter 10, as illustrated in FIG. 2, includes a generally cylindrical body member 42 having a central chamber or cavity 46 in which a plunger 48 is slidably mounted in a coaxial relationship. A snap-ring S0 is disposed in an annular groove 52 located in the central cavity 46.

The body member 42 includes an upper cavity which is in part defined by an internal annular surface 54. The face member 26 is slip fitted in the upper cavity and an outer annular surface 56 of the face member 26 is disposed adjacent to the annular surface 54. A shoulder 58 is provided on the body member 42 to locate the face member 26 in the upper cavity. The shoulder 58js I the passageway 66 between the fluid reservoir 60 and a discontinuous shoulder and enables fluid to flow from internal portions of the lifter between the face: member 26 and the body member 42. The face member 26 cooperates with the body portion 42 to define a fluid reservoir 60 in the upper cavity of the body member 42 for holding oil or other lubricant therein. The reservoir 60 is connected in fluid communication with an oil pump or other source of lubricant under pressure (not shown) by a passageway 62 in the body member 42 and suitable holes or apertures in the engine block 14 not illustrated. The size of reservoir 60 i.e., its depth and diameter, may be varied to tailor the lifter to individual engine requirements.

A pressure chamber 64 is defined between the plunger member 48 and the body member 42. A fluid passageway 66 is provided in the body member 42 to provide for fluid communication between the reservoir 60 and the pressure chamber 64. A check valve assembly 68 cooperates with the plunger member 48 to compensate for dimensional changes in the valve gear 12 by varying the axial extent of the hydraulic lifter 10 to thereby maintain a predetermined relationship between the cam 16 and valve 20. The check valve assembly 68 controls the flow of fluid from the reservoir 60 to the pressure chamber 64 by opening and closing the pressure chamber.

The check valve assembly 68 includes a check valve ball member 70, a retainer member 72 and a check valve spring 74. The retainer 72 is held against the bottom surface of the body member and for illustrated purposes is shown as having its shoulder portions '76 thereof press fitted into an annular recess 78 in the body member 42. However, it-should be appreciated that the plunger spring 86 may be utilized to hold the retainer 72 in place. The check valve spring 74 engages with the check valve member and the bottom portion of the retainer member 72 and urges the valve member 70 into engagement with a valve seat 80 disposed at one end of the passageway 66. When the check valve is in a closed condition, as illustrated in FIG. 2, fluid flow from the reservoir 60 to the pressure chamber 64 is prevented. When the va1ve. member.70 is in an open condition, as illustrated in FIG. 3, fluid flow from the reservoir 60 to the pressure chamber 64 may occur. To this end the retainer 72 includes openings 82 therein to enable fluid to flow through the passageway 66 through the openings 82 in the retainer 72 to the pressure chamber 64. It should be noted that the check valve operates as a one way valve enabling fluid to flow from the reservoir 60 to the pressurechamber64. To this end the valve member 70 opens in response to a partial vacuum created in the pressure chamber 64 by movement of the plunger member 48 outwardly of the body member 42 by the plunger spring 86 after the valve 20 seats to maintain zero lash in the valve gear.

While the lifter 10 is illustrated as utilizing a check valve spring 74, the valve spring 74 may be eliminated when using the lifter with a relatively rigid valve gear of an overhead cam engine. Eliminating the check valve spring in a very rigid valve gear provides for a certain degree of freedom as the normal position of the check valve when the lifter is engaged with the base circle of the cam will be opened to provide a minor amount of movement of .the lifter due to cam bearing clearance, base circle run out and deflection of the camshaft. With no check valve spring the travel of the valve member 70 is limited by the retainer-72 and the check valve is closed by fluid flow when cam lift is encountered.

The fluid in the pressure chamber 64 is subjected to pressure by the downward force of the cam 16 when the operating portion 36 thereof engages with the face member 26 of the lifter 10. Some of the fluid in the pressure chamber 64 is forced out of the chamber along a relatively small clearance commonly referred to as a leak-down passageway 84 disposed between the cylindrical peripheral surface of the plunger member 48 and the cylindrical inner surface of the body 42. This leakage of fluid is commonly referred to as leakdown and results in a slight inward movement of the plunger member 48 relative to the body 42 and a corresponding contraction in the pressure chamber 64. Generally, the inward movement of the plunger member 48 is on the order of 0.0Q2-0.003 inches during each valve opening event. This contraction of the lifter enables the lifter to accommodate valve contraction and still maintain zero lash in the system. When the force against the outer face member 26 is reduced by engagement of the base circle 28 of the cam 16 with the face member 26, a plunger spring 86 in the pressure chamber 64 biases plunger member 48 outwardly of the body member 42 and bias the body member 42 upwardly to maintain the face member 26 in engagement with the cam 16. This outward movement of the plunger member 48 causes the pressure chamber 64 to expand slightly and reduces the fluid pressure within the chamber. Fluid pressure in the reservoir 60 is then greater than the fluid pressure in the chamber 64 and the valve member 70 of the check valve assembly 68 is moved out of engagement with the valve seat 80 against the influence of the check valve spring 74 toenable fluid to flow from the reservoir 60 through the passageway 66 to the pressure chamber 64 to replace the fluid which previously leaked out of the pressure chamber.

If the effective length of the valve gear 12 should increase from one revolution of the cam 16 to the next, the distance which the plunger spring 86 moves the plunger 48 and body 42 and the amount of replacement fluid which flows into the pressure chamber 64 is decreased to thereby decrease the effective axial length of the hydraulic lifter 10. Conversely, if the effective length of the valve gear 12 should decrease from one revolution of the cam member 16 to the next, the plunger spring 86 moves the plunger member 48 and body member 42 outwardly to expand the pressure chamber 64 and enables a relatively large amount of replacement fluid to flow into the pressure chamber 64 to thereby effect an increase in the axial length of the lifter 10. In this manner, the check valve assembly 68, plunger spring 86, and plunger member 48 cooperate to maintain a predetermined relationship, i.e., zero lash, between the cam 16 and the valve 20 even though the effective dimensions of the valve gear 12 change during operation of the engine 14. Of course, a flat type check valve member could be used instead of the ball member 70 which is illustrated.

The face member 26 which is slidably fitted in the upper cavity of the body member 42 includes an outer surface 90 which is in continual engagement with the rotating cam 16. To prevent abnormal wear of the surface 90 and the cam 16 a flow of lubricant must be provided to the surface 90 of the face member 26. To this end, the outer peripheral surface 56 of i the face member 26 cooperates with the inner surface 54 of the body member 42 to define a leakage passageway 92 which provides for fluid communication between the reservoir 60 and the surface 90 of the face member 26. The leakage passageway 92 enables fluid to flow from the reservoir 60, around the discontinuous shoulder portions 58, through the passageway 92 and to the surface 90 during normal reciprocating movement of the lifter 10. This flow of lubricant, which will be metered by the cooperating surfaces 54 and 56 of the body member 42 and face member 26 respectively, will be effectively controlled to provide for proper lubrication of the cam 16 and the surface 90 of the face member 26.

The passageway 92 will also provide for the leakage of any air which might become trapped internally of the lifter 10. It should be appreciated that since the passageway 92 is disposed above the reservoir 60 and the pressure chamber 64 any air which might become trapped in the pressure chamber 64 or the reservoir 60 will move in an upwardly direction through the reservoir 60 to the passageway 92. The air will then flow through the passageway 92 and out of the lifter 10. This will prevent air lockup in the lifter due to the entrapment of air in the internal cavities therein. This is the distinct advantage over known lifters in that aleakage passageway is provided to prevent air lockup which occurs when air becomes trapped in the internal cavities of the lifter 10. The entrapment of air in the pressure chambers 64 would effect erratic operation of the lifter 10 since the compressibility of air is not similar to the compressibility of the oil or lubricating fluid which is normally disposed in the pressure chamber 64. The above undesirable conditions are effectively presented by the provision of the passageway 92 which directs air from the internal parts of the lifter 10. It should be appreciated that by making the face member a separate piece complete freedom of choice in the face member material may be obtained to eliminate fabrication problems in the lifter. Specifically, the material out of which the face member 26 is constructed can be such as to give the face surface an exceedingly hard surface for long life. Moreover, the outer diameter of the face member 26 can be controlled to provide the proper leakage path for the lubricant flowing from the reservoir 60 to the surface 90 of the face member 26. Preferably, the cam 16 and the face member 26 have surfaces which engage to effect rotation of the face member 26 relative to the body member 42 upon reciprocation of the lifter. The rotation of face member 26 insures that the passageway 92 remains free of debris and does not become blocked.

From the foregoing, it should be apparent that a new and improved hydraulic valve lifter has been provided for use in a direct acting overhead camshaft valve gear which includes a body member, a plunger member and a face member. The face member cooperates with the body member to define a fluid reservoir and the plunger member cooperates with the body member to provide a pressure chamber for adjusting the axial extent of the lifter. The face member also cooperates with the body member to define a leakage passageway for air which may become trapped in the lifter. The leakage passageway enables the air to leak therethrough so as to prevent air lockup of the lifter. Moreover, the leakage path also provides for lubricant flow from the reservoir to the face member to lubricate the cam engaging surface thereof and the cam.

I claim:

1. A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine comprising a body member, a face member located at least in part within said body member and having a cam engageable outer surface and an inner surface, a plunger member located at least partially within said body member, a fluid chamber defined in part by said body member for receiving lubricating fluid from a source of fluid under pressure, and a leakage passageway defined by said body member and said face member providing for fluid flow from said fluid chamber to said cam engageable outer surface of said face member, said leakage passageway providing for the flow of lubricating fluid to said cam engageable outer surface of said face member to effect lubrication of said cam engageable outer surface and permitting air flow from said fluid chamber to prevent air lockup of said hydraulic valve lifter.

2. A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine as defined in claim 1 wherein said face member is slip fitted in an opening in said body member and said leakage passageway is defined by the outer diameter of said face member and the inner diameter of said opening in said body member.

3. A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine as defined in claim 1 wherein said leakage passageway is defined by an outer peripheral surface of said face member and an inner surface of said body member.

4. A hydraulic valve lifter for use in a direct acting overhead camshaft valve gear of an internal combustion engine as defined in claim 3 wherein said fluid chamber is a fluid reservoir defined by said inner surface of said face member and an internal surface 'of said body member.

5. A hydraulic valve lifter for-use in a direct acting overhead camshaft valve gear of an internal combustion engine as defined in claim 4 further including a pressure chamber located between said body member and said plunger member, a fluid passageway disposed in said body member and providing fluid communication between said fluid reservoir and said pressure chamber, valve means for controlling the fluid flow through said fluid passageway from said fluid reservoir to said pressure chamber, and a leak-down passageway defined by said plunger member and said body member for providing for fluid flow from said pressure chamber.

6. A hydraulic valve lifter for use in a valve gear of an internal combustion engine comprising a body member, a plunger member located at least partially within said body member, a face member slip fitted in said body member, said face member having an outer cam engageable surface, an outer peripheral surface and an inner surface, a fluid reservoir defined by said inner surface of said face member and said body member, a pressure chamber located between said body member and said plunger member, a fluid passageway located within said body member and providing for fluid communication between said fluid reservoir and said pressure chamber, and a leakage passageway defined by said outer peripheral surface of said face member and said body member providing for fluid communication between said reservoir and said outer cam engageable surface of said face member, said leakage passageway providing fluid flow from said reservoir to said outer cam engageable surface of said face member, said fluid flow effecting lubrication of said outer cam engageable surface.

7. A hydraulic valve lifter as defined in claim 6 further including check valve means disposed in said fluid passageway for controlling the fluid flow from said fluid reservoir to said pressure chamber to thereby control the axial extent of said hydraulic valve lifter.

8. A hydraulicvalve lifter for use in a direct acting overhead camshaft valve gear with an internal combustion engine comprising a body member, a plunger member located at least partially within said body member, a fluid reservoir disposed in said body member for receiving lubricating fluid from a source of fluid under pressure, a face member disposed in an opening in said body member above said fluid reservoir when said hydraulic valve lifter is in a normal operating condition, said face member including a cam engageable surface and an outer peripheral surface, said outer peripheral surface cooperating with said body member opening to provide a leakage passageway providing fluid flow from said fluid reservoir to said cam engageable outer surface.

9. A hydraulic valve lifter as defined in claim 8 further including a pressure chamber defined between said body member and said plunger member, a fluid passageway disposed in said body member and communicating at one end thereof with said fluid reservoir and the opposite end thereof with said pressure chamber, said fluid passageway providing for fluid flow from said fluid reservoir to said pressure chamber, and check valve means for controlling the fluid flow through said fluid passageway to thereby control the axial extent of said lifter.

10. A hydraulic valve lifter as defined in claim 8 wherein said face member is slip fitted in said opening in said body member.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2116749 *Sep 25, 1933May 10, 1938Eaton Mfg CoCompensating valve operating device
US2158222 *Nov 17, 1936May 16, 1939Dayton Ernest LCompensating valve mechanism
US2175467 *Dec 21, 1938Oct 10, 1939Johnson Charles EHydraulic tappet
US3176669 *Feb 27, 1964Apr 6, 1965Motomak G M B HSelf-adjusting hydraulic valve lifter for piston engines
US3385274 *Jul 13, 1967May 28, 1968Gen Motors CorpVariable stroke hydraulic valve lifter
US3406668 *Jan 19, 1968Oct 22, 1968Ford Motor CoHydraulic tappet assembly
US3509858 *May 20, 1968May 5, 1970Gen Motors CorpOverhead cam valve lifter
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3877446 *Aug 21, 1974Apr 15, 1975Gen Motors CorpHydraulic valve lifter
US4319548 *Jul 30, 1979Mar 16, 1982Volkswagenwerk AktiengesellschaftInternal-combustion engine having two rows of cylinders
US4483281 *Jun 27, 1983Nov 20, 1984Black Alfred APoppet valve spring retainer with integral hydraulic tappet
US4580533 *Mar 22, 1984Apr 8, 1986Mazda Motor CorporationValve mechanism having variable valve timing
US4582029 *Sep 9, 1983Apr 15, 1986Mazda Motor CorporationValve timing control system for internal combustion engine
US4777842 *Apr 24, 1987Oct 18, 1988Toyota Jidosha Kabushiki KaishaStructure of camshaft bearing
US5005541 *Jul 24, 1990Apr 9, 1991Otai Tekko Kabushiki Kaisha And Koyo Seiko Co., Ltd.Hydraulic valve lifter
US5018488 *Apr 25, 1990May 28, 1991Jaguar Cars LimitedHydraulic tappets
US6397806 *May 25, 2001Jun 4, 2002Unisia Jecs CorporationEngine valve assembly for internal combustion engine
EP0030780A1 *Aug 11, 1980Jun 24, 1981Eaton CorporationLight weight tappet for direct-acting valve gear
Classifications
U.S. Classification123/90.33, 123/90.55, 123/90.35
International ClassificationF01L1/25, F01L1/20
Cooperative ClassificationF01L1/25
European ClassificationF01L1/25