US3902467A

US3902467A - Lash adjuster and meter means

Info

Publication number: US3902467A
Application number: US300270A
Authority: US
Inventors: Richard D Cornell
Original assignee: Johnson Products Inc
Current assignee: Sealed Power Technologies LP; Kodiak Partners Corp; Johnson Products Inc
Priority date: 1971-09-13
Filing date: 1972-10-24
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

Metered oil is supplied to the rocker arm through the tappet body which includes a closure member movable in the tappet and engageable with the rocker arm directly or a push rod extending therefrom. The closure member is formed of upper and lower parts with at least one of the parts having grooves or slots formed therein which in cooperation with the other part form oil conducting passageways. In one embodiment, the diameter and thickness of the lower part in cooperation with the inner bore of the tappet in which it is located determines the degree of metering. In another embodiment, the size and configuration of slots or grooves in one or both of the parts determines the degree of metering.

Description

United States Patent [191 Cornell [4 1 *Sept. 2, 1975 LASH ADJUSTER AND METER MEANS [75] Inventor: Richard D. Cornell, Muskegon,

Mich.

[73] Assignee: Johnson Products Division of Sealed Power Corporation, Muskegon,

Mich.

' Notice: The portion of the term of this patent subsequent to Feb. 20, 1990, has been disclaimed.

[22] Filed: Oct. 24, 1972 21 Appl. No.: 300,270

Related US. Application Data [63] Continuation-impart of Ser. No. 179,856, Sept. 13,

1971, Pat. No. 3,717134, which is a continuation in-part of Ser. No. 29,915, April 20, 1970, Pat. No.

[52] US. Cl. l23/90.35; 123/9046; 123/9055; 184/69 [51] Int. Cl. F01m 9/10 [58] Field of Search 123/9035, 90.55, 90.56,

[56] References Cited UNITED STATES PATENTS 3,153,404 10/1964 Van Slooten 123/90.43

3,439,660 4/1969 Lesher... 123/9035 3,542,001 11/1970 Line 123/9043 3,717,134 2/1973 Cornell 123/9035 Primary Examiner-Manuel A. Antonakas Assistant Examiner-Daniel J. OConnor Attorney, Agent, or FirmPrice, Heneveld, Huizenga & Cooper [5 7] ABSTRACT Metered oil is supplied to the rocker arm through the tappet body which includes a closure member movable in the tappet and engageable with the rocker arm directly or a push rod extending therefrom. The closure member is formed of upper and lower parts with at least one of the parts having; grooves or slots formed therein which in cooperation with the other part form oil conducting passageways. In one embodiment, the diameter and thickness of the lower part in cooperation with the inner bore of the tappet in which it is located determines the degree of metering. In another embodiment, the size and configuration of slots or grooves in one or both of the parts determines the degree of metering.

11 Claims, 8 Drawing Figures PATENTEUSEP 2% 3,902 467 saw 210; 2

1 LASH ADJUSTER AND METER NEANS SUMMARY OF THE INVENTION In accordance with the invention, a tappet construction utilizes a closure element having an upper and lower part. The closure element includes a longitudinal opening extending through the upper part to at least the upper surface ofthe lower part. A slot is formed in at least one of the surfaces of engagement between the 1 upper and lower parts and extends from the opening to of parent application Ser. No. 29,915, filed A r. 20,

1970 and entitled METERED MECHANICAL TAP PET WITH SLOTTED PUSH ROD SEA said parent application having issued on Oct. 26, 1971, into US. Letters Pat. No. 3,614,942. I

BACKGROUND OF THE INVENTION This invention relates to hydraulic tappets or lash adjusters, and more particularly to a tappetconst ruction utilizing a novel closure element which also meters the lubricating oil flow directed to the rocker arm.

In present commercial practices, it is widely accepted to lubricate the rocker arms by oil forced from the tappet or galley either through hollow push rods which are seated in alclosure element defining a push rod seat or stud member having a fulcrum ball seated in-the rocker arm itself. This-flow of oil, however, must be metered accurately so that the supply is neither toosmall nor too large. Too much oil results in loss to the valve guides and subsequent leakage and collection of dirt while too little results in premature fatigue of the various parts. Proposals which utilize a restricted cylindrical orifice to meter the oil are inadequate in that they are so small they are susceptible to plugging since dirt and other foreign matter which ultimately enters the oil supply collect around the orifice to reduce the meter rate or stop it completely. Thus, it is desirable to meter the oil through a relatively flat passageway preferably defined by two or more elements which move or rotate relative to each other. One commercially successful form of this type is shown in US. Pat. No. 3,358,658 which utilizes a metering disc. I

Present tappet orlash adjuster construction generally requires a machined shoulder on the interior'wall of the tappet body (in a mechanical tappet) or the plunger (in a hydraulic tappet) on which the closure elements rests. In other instances, the closure element includes a machined shoulder for abutting or resting on the upper end of the plunger of a hydraulic tappet, Such machining is relatively expensive. Also, the closure element itself has heretofore required a high degree of to]- erance and machining which in many cases includes the boringor drilling of some type of passageway to permit the oil to flow through the closure element to the hol-. low push rod or rocker arm. It will be appreciated that cost is of extreme importance in tappet construction since the volume of tappetsiused inthe automobile industry is extremely large.

Another drawback of the prese nt'art is the lack of in terehangeability of parts in tappetconstmction or the ability to vary the amount of on flow unless the whole tappet is replaced. Thus, there is a need today for a new and improved tappet construction which provides greater flexibility, complete accura'cy'in oil flow and at the same time significantly reducing the overall manufacturing costs. i

the space between the lower seat part and inner wall of the tappet body or plunger. The opening, slot and space form part of the passageway between the oil reservoir and rocker arm.

The two part construction of the closure element greatly reducesthe amount of machining required on I the closure element itself. Each part of the seat can be formed of heat sintered and treated outer metal parts since the slot on one of the exposed surfaces and opening does not require high tolerance machining.

In one embodiment, the closure element is a push rod seat, the upper part having a push rod seating surface with openings extending longitudinally to the surface for communication with a hollow push rod. In another embodiment the closure element is a stud means, the upper part having a fulcrum ball rested in the rocker arm. The opening in this case extends through the ful crurn ball for communication with the rocker arm.

In a more narrower aspect, the spacing between the outer wall of the lower part and the inner wall of the tappet body or plunger defines the metering means. This annular path will not plug since the path is of flattened cross section and the lower part of the closure element continually moves and rotates relative to the tappet body. This will crush or dispose of any foreign matter which might be positioned therebetween. The meter rate can be simply and easily adjusted by varying the axial thickness of the lower seat part. Nothing else in the entire tappet construction need be altered.

In an alternative aspect of the invention, metering is achieved in the slot formed in one of the surfaces of engagement between the upper andlower partswhich slot is also free from plugging since the lower part will move relative to the upper part. In hydraulic tappets, it is also envisioned that metering may be achieved in that part of the passageway formed .between the engaging surfaces of the lower part of the closure element and the plunger utilized in a hydraulic tappet. The two part construction of the closure element permits less costly replacement of either part as well as the amount of machining involved.

: DESCRIPTION OF THE DRAWINGS 3 of yet another alternative embodiment according to this invention;

FIG. 6 is a fragmentary view similar to FIGS. 1, 3 and 5 of still another alternative embodiment;

FIG. 7 is an elevation view partially in cross section of an overhead cam valve train; and

FIG. 8 is a transverse sectional view of an alternative embodiment of the invention illustrating the hydraulic lash adjuster shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The novel push rod seat provided by this invention and the means for metering lubricating oil through the closure element to a push rod or rocker arm are applicable regardless of whether the tappet construction is of the mechanical or hydraulic type. Briefly, in the hy draulic or mechanical tappet arrangement a tappet body is mounted for reciprocal movement within an engine block and is actuated by a cam shaft and cam lobe in a conventional fashion which for that reason is not shown or described in detail. The tappet body generally includes a closure element defining a push rod seat means for receipt of a hollow push rod having a passageway extending up to the rocker arm and valve train assembly. Lubricating oil is metered through the tappet, the oil flowing through a passage in the engine block for entry into a port provided through the wall of the tappet body.

In an overhead lash adjustor arrangement, the tappet body does not reciprocate within the engine block but rather the plunger and closure element reciprocate within the tappet body to provide lash adjustment. Also,'the closure element includes a fulcrum ball which rests in a recessed seat formed in the rocker arm such that the lash adjuster is connected directly to the rocker arm. Lubricating oil is metered through a passageway in' the closure element directly to the rocker arm.

This invention, in one of its aspects provides positive metering which can be varied by utilizing a novel push closure element comprising an upper and lower part having slots or grooves defining flow passageways for the metered oil.

Referring now to FIGS. 1 and 2 in detail, a hydraulic tappet 10 is shown with a tappet body 12 in which is mounted a push rod seat means 14 above a plunger 16, the seat means having a push rod seating surface 18 for receipt of a hollow push rod 20. Tappet body 12 is generally cylindrical in shape having a closed end 22 whose outer surface 24 provides a cam engaging surface for actuation by the cam lobe (not shown). The opposite end 26 is open to permit insertion of plunger 16 and push rod seat means 14 which closes end 26.

The outer wall 28 of tappet body 12 includes an annular groove 30 which is axially extended so that the engine block passage is in constant communication with groove 30 regardless of the reciprocal movement of tappet 10 within the engine block. A port 32 connects groove 30 with the inner portion of the tappet body which is defined by an axial bore 34. This permits constant communication between the engine block passage and port 32 of the tappet body. Bore 34 extends through the tappet body from open end 26 to closed end 22. The inner wall 36 of bore 34 has a circular configuration. A plurality of axially spaced recesses or

grooves

38, 40 and 42 having a diameter greater than bore 34 are provided in tappet body 12. The bottom or lower groove 38 cooperates with plunger 16 and a valve mechanism 44 to provide lash adjustment for the push rod, the details of which will not be described herein since they are well known. The intermediate groove 40 is aligned with port 32 so that regardless of the axial position of plunger 16 or push rod seat means 14, oil flowing through port 32 will have access to surround the plunger or seat means via groove 40. The upper groove 42 is provided for receipt of a lock ring 45 to prevent unintentional removal of push rod seat means 14 and plunger 16.

Plunger 16 also has an overall cylindrical configuration with both the upper and lower ends 46 and 48 being open. The lower end 48 has a more restricted opening than the upper end for cooperation with the lash adjustment valve means 44 referred to briefly above. The outer wall 50 of plunger 16 corresponds dimensionally to the diameter of bore 34 of the tappet body so that plunger 16 is movable axially within bore 34. Some clearance is provided between the outer wall of plunger 34 and the inner wall of tappet body 12 so that oil will flow therebetween to provide a friction-free contact between the surfaces. The upper end 46 of plunger 16 is necked down in comparison to the overall diameter of plunger 16 so that an annular cavity or spacing 52 is provided between inner wall 36 of tappet body 12' and upper end 46 of plunger 16. The provision of spacing 52 eliminates the need of groove 40. The elimination of groove 40 increases the economical advantages provided by this invention and although it is shown in FIG. 1, it will be appreciated that one important aspect of this invention is the utilization of the unique push rod seat means 14a in existing tappet body construction. However, as a result of this invention, it is no longer necessary to machine groove 40 into new tappet body constructions. The upper end 46 of plunger 16 provides a shoulder 54 upon which seat means 14 is indexed. The interior portion 56 surrounded by the plunger walls and seat means provides a reservoir for the lubrication oil within the tappet body.

Turning now to the push rod seat means configuration, seat means 14 is comprised of upper and

lower parts

58 and 60, respectively both of which are generally disc-shaped. Upper part 58 has an outer wall 62 the diameter of which corresponds roughly to that of tappet body bore 34 so that upper part 58 is slidable axially within the bore. The top surface 64 includes push rod seating surface 18 which has an interior crater-like surface for receipt of push rod 20. The outer portion of surface 64 defines an annular shoulder 66 which is engageable with lock ring 45, the latter preventing the seat and plunger from being unintentionally removed from the tappet body when the ring is positioned in groove 42. The bottom surface 68 of upper part 58 is engageable with the top surface 70 of lower part 60 and supported thereby. An opening 72 extends axially through upper part 58 from push rod surface 18 to lower part 60.

Lower part 60 in addition to top surface 70 includes a bottom surface 74 (FIG. 2) which engages upper end 54 of plunger 16 and is supported thereby. The outer wall 76 of lower part 60 has a diameter generally equal to that of tappet body bore 34 so that the lower part of seat means 60 is likewise movable axially within tappet body 12.

The outer diameter of lower seat part 60 is preselected so that a restricted annular pathway 80 is provided between outer wall '76 of seat part 60 and inner wall 36 of bore 34. The upper surface 70 of lower seat part 60 includes a diametrical slot 82 which forms a flow passageway from seat opening 72 to pathway 80. The bottom surface 74 of lower seat part 60 also includes a diametrical slot 84 (FIG. 2) similar to slot 82 to provide a means for flow communication between port 32, spacing 52, and reservoir 56 to permit oil flow into and out of reservoir 56 up through annular pathway 80 into slotted passageway 82 and opening 72 into push rod.

Having described the various elements in the embodiment shown in FIGS. 1 and 2, its operation will now be described in detail. Oil flowing from the engine block passageway into groove leads directly into port 32 for entry into tappet body 12. Annular groove 30 on the outer wall of tappet body 12 is of sufficient axial length such that there is constant flow communication between the engine block passageway and port 32 regardless of the vertical orientation of tappet 10. Flow through port 32 surrounds plunger 16 by flowing through interior annular groove and also into interior spacing 52. From here, flow into and out of reservoir 56 is permitted through unrestricted slot 84. In accordance with this embodiment, the flow of lubricating oil to hollow push rod 20 is metered between inner wall 36 of the tappet body and outer wall 76 of lower seat part 60. By preselecting the diameter and thickness of lower seat part 60 the total cross-sectional flow area through annular path 80 is determined. By making this less than the cross-sectional flow area through

slots

82 and 84 and opening 72, the entire metering of the lubrieating oil is achieved between the top and

bottom surfaces

70 and 74 of lower seat element 60. Once the metered flow has passed this surface, relative unrestricted flow through slot 82 directs the oil through opening 72 and up into the hollow push rod 20. It will be appreciated, that while there is some clearance between outer wall 62 of upperseat element 58 and inner wall 36 of tappet body 12, so long as this cross-sectional flow area is less than that of slot 82 and opening 72, the metered flow will follow the path of least resistance into the push rod.

Since the rate or volume of metered oil flowing into the push rod is a function of the crosssectional flow area of annular pathway 80 and its axial or longitudinal length, this invention provides an extremely simplified means for varying the volume of lubricating oil into the push rod simply by inserting a new lower seat part 60 having a different thickness. This can be done without altering or changing the configuration of any of the other elements of tappet 10. It will be appreciated that lower seat part 60 moves both axially and rotationally with respect to inner wall 36 as the tappet is in use so that annular pathway 80 is prevented from becoming clogged.

Referring specifically to FIG. 2, it will be appreciated that the movement of lower seat part 60 within tappet body bore 34 of the tappet body will sometimes cause a very slight eccentric positioning of the lower seat member within bore 34. According to this invention, this does not significantly alter the flow rate through pathway 80 since the overall cross-sectional flow area remains a constant. However, it is realized that the portion of lower seat element 60 in abutment with inner wall 36 could coincide with one of the openings of

slot

82 or 84. Preferably, the cross-sectional flow area of

slots

82 and 84 is large enough to accommodate full metered flow through either end of the slots. However,

a plurality of slots are envisioned in those situations where this may not be practical. Thus, the top or bottom surfaces of lower seat element 58 could include more than one slot.

Before turning to an examination of other altemativcs shown in the drawings, it will be appreciated that slot 82 could just as easily be disposed in the bottom surface 68 of upper seat element 58 without departing from the teachings herein. In fact, there may be instances wherein it is desired that slot 82 perform the metering function. However, it will also be appreciated that the

provision'of slots

82 and 84 in lower seat part 60 permits this part to be inserted indiscriminately, i.e., it is symmetrical in the sense that either surface can face up or down.

Referring now in detail to FIGS. 3 and 4, an alternative use of the two-part push rod seat in combination with a slightly altered plunger and tappet body is shown. Except for these alterations, like reference numerals with the suffix a are used to correspond to similar elements described with respect to FIG. 1. Tappet body 12a has been altered by eliminating interior groove 40 shown in FIG. 1. Plunger 160 has been modified to permit more unrestricted flow into and out of reservoir 56a without altering the configuration of the lower seat part 60a. Again, it will be appreciated that the interchangeability of parts is desirable in that the ability to utilize lower seat parts identical to seat part 60 in other configurations reduces overall costs. Hence, where it is necessary to provide larger crosssectional flow ability between reservoir 56a and annular spacing 52a, an alternative plunger 16a is incorpo rated which permits usage of the same lower seat parts 60a corresponding to seat part 60.

The modification of plunger 16a is illustrated in detail in FIG. 4. Instead of the upper end 46a of plunger 16a being necked down as described with respect to FIG. 1, a plurality of circumferentially spaced radially projecting grooves or slots are provided to permit free flow of oil into reservoir 56a regardless of the rotary or axial position of plunger 16a. The remaining upper surface areas 92 intermediate slots 90 on upper end 46a provides an annular intermittent shoulder on which lower push rod seat part 60a rests. Preferably,

slots 90 are convergent toward the center of plunger 16a so that they are widest at the point of oil entry from the engine block passageway. This prevents the slots fromacting as a metering means in that an unrestricted amount of oil is permitted to flow through port 32a into the circumferentially spaced slots 90 adjacent inner wall 36a of tappet body 12a. The remaining portions of the tappet assembly are identical to that shown in FIG. 1 and although slot 82a is shown in the lower surface 74a of lower seat part 60a, it does not perform the primary function of providing a flow passageway into and out of reservoir 56a. Rather, it permits the insertion of lower part 60a in an indiscriminate fashion since the part is reversible. The function and operation of the unique push rod seat means 14 a is identical to that described with reference to FIG. 1.

Turning now to FIG. 5, another use of the novel two part seat means is shown. In this combination is illustrated a more conventional hydraulic tappet construction wherein the seat means is positioned on an internal shoulder in the plunger. Identical reference numerals with the suffix b will be used for similar parts corresponding to similar elements in FIGS. 1 and 3.

Although the overall construction of tappet assembly 10b is conventional, it will be described briefly herein to illustrate how the unique push rod seat means 1412 provided by this invention can be used in more conventional tappet assemblies.

Plunger 16b is somewhat distinguishable from those described previously in that the upper end 46b of plunger 16b extends beyond and above port 32b where oil enters the tappet body. The interior portion of upper portion 46b has an enlarged cross section with regards to the remainder thereof to provide a shoulder 94 on which push rod seat means 14b is seated. Also, the introduction of oil into reservoir 56b is different than that described. Namely, an interior groove 40b is provided to permit oil entering through port 3212 to be disposed annularly around upper portion 46b of the plunger. In addition, adjacent upper portion 46b of plunger 16b, an annular groove 96 is provided in the outer wall of plunger 16b for communication with groove 40b. A port 98 through the wall of plunger 16]) provides the flow passageway of oil into reservoir 56b. Flow out of reservoir 56b to push rod 20b is provided through slot 84b in a fashion similar to that described with regards to the embodiment shown in FIG. 1. That is, oil flows through slot 84b for metering through annular restricted passageway 80b as defined by the dimensions of lower seat part 60b into the upper diametrical slot 82b of lower seat part 60b and thence through passageway 72b into the hollow push rod. Thus, it will be appreciated that the unique push rod seat means comprising an upper and lower seat part 58b and 60b can be conveniently utilized in more conventional existing tappet assemblies.

The thickness of lower seat part 60b is shown in FIG. 5 to be less than those shown with regards to the embodiments described in FIGS. 1 and 3. This is simply to illustrate that the overall metering rate can be varied by varying either the diameter of lower seat part 60b or its thickness. In the preferred embodiments shown, this is all that need be modified in the tappet assembly in order to vary the metering rate.

Referring now to FIG. 6, another alternative embodiment of this invention is shown wherein the novel push rod seat means is utilized in a mechanical tappet. Similar reference numerals with the suffix c are used to designate similar elements as described with regards to FIGS. 1-5. The same metering function is provided by push rod seat means 143 in that it is comprised of an upper and lower seat part 580 and 60c identical to that described with regards to FIG. 1. The essential distinction here is that in a mechanical tappet assembly such as shown in FIG. 6, there is no plunger mounted within the tappet body. Rather, oil entering the body through port 320 goes directly into reservoir 56c. Axial bore 34(- is comprised of an upper and lower part, the upper part being positioned and spaced above port 320 and having an enlarged cross section with relation to the lower part. The juncture of the two parts provides a shoulder 100 on which push rod seat means 146 is positioned. Hence reservoir 560 is defined by the inner wall of bore 340 in the lower portion which is closed by lower seat part 600. Oil flow from reservoir 560 to annular path 800 is achieved in the same way as described previously by flow through slot 840 in the lower surface of lower seat part 606. The thickness and diameter of lower seat part 600 defines the overall cross-sectional flow area of annular path 806 and determines the meter rate of the tappet assembly. Meter flow is directed to push rod 20c through slot 820 and passageway 720 in the same fashion as described previously. However. the same savings in cost and simplicity and construction are achieved as described previously. In addition, the embodiments shown illustrate further savings in that seat means 14c can be used interchangeably in a hydraulic or mechanical tappet assembly.

Referring now to FIGS. 7 and 8, a hydraulic lash adjuster is illustrated which is specifically designed for use in an overhead cam shaft engine. In a lash adjuster of this type, a valve 102 having a spring 104 and retainer 106 is actuated by a rocker arm 108 through a cam shaft 110 and cam 112. Rocker arm 108 pivots about a solid or closed socket 114 on adjuster 100. The adjuster body does not move in the engine block (not shown) and with reference to FIG. 8, contains a body with a plunger 122. Plunger 122 is biased in the upward position against the closed socket 114 of rocker arm 108 through a spring 124. The plunger 122 has an internal cavity or oil reservoir 126 which opens into a bottom compression chamber through checkvalve plate 128. A spring 130 biases valve plate 128 against the bottom of plunger 122. A valve retainer 132, which holds the checkvalve assembly in place is held against the bottom of plunger 122 by spring 124.

The upper open end of body 120 is closed by a twopiece closure element 134 having an upper part 136 and a lower part 138. The reciprocal motion of plunger 122 and closure element 134 is limited at the lower extremity by shoulder 127 and at the upper extremity by a retainer ring 129 which prevents further upward movement of plunger 122 and closure element 134 due to an annularly projecting shoulder 131 formed at the lower portion of element 136.

The lower part 138 of closure element 134 is identical to the lower part 60, 60a, etc. of the pushrod seat elements described herein previously. That is, it includes a diametrically positioned upper slot 140 and a lower diametrically positioned slot 142 transverse to slot 140 corresponding to

slots

82 and 84 illustrated in FIG. 2. The lower part 138 of closure element 134 rests on the upper end of plunger 122 with slot 142 defining a flow passageway to and from the internal wall 144 of body 120 relative to reservoir 126. The upper portion of plunger 122 is necked down to define an annular recess 146 around the upper end of plunger 122. The lower part 138 of closure element 134 has a diameter less than the inner diameter of body 120 to permit oil flow about lower part 138 into slot 140.

The upper part 136 of closure element 134 is shown to be relatively elongated when compared with the upper parts 58, 580, etc. of the pushrod seat elements previously described. It is distinguishable in other respects in that it includes a spherical nose 150 which is seated in and captured within the closed socket 114 of rocker arm 108. Referring to FIG. 7, the spherical nose 150 acts as a fulcrum and is retained in seat 114 by a spring 152 which clips into an annular recess 154 (FIG. 8) formed in the upper portion of element 136. A central longitudinal opening 156 extends centrally through the upper part 136 of closure element 134 and when the upper part is in abutment with lower part 138, oil flow is permitted from slot 140 up the center passage way 156 for lubrication of rocker arm 108. Referring to FIG. 7, a passageway 1115 may be provided through the rocker arm where it is desired to utilize the metered oil to lubricate the contact surfaces of cam 112 and rocker arm 108. I V I The path of lubricating oil through lash adjuster 100 should now be apparent. Lub rica tingpil enterscavity 126 through a port l 58 through body 120 which is in communication with annular recess l46. The oil passes through slot 142 into cavity 126 through the bottom portion of plunger 122' and into the bottom compression chamber 125. Oil also flows from cavity 126 through the annular clearance'l46 between lower closure element part 138 and the inner wall of plunger body 120 from whence it flows through slot 140 into central passageway 156 to socket 114of rocker arm 108. In accordance with the prior tea'chings described herein, the flow rate can be metered by selecting the diameter of lower closure element 138 to define a re stricted annular flow passageway between element 138 and the inner walls of plunger 120. Alternatively, if this clearance is relatively large, the metering could be effected through the proper selection of the crosssectional area of slot 140. Preferably, metering is provided through the annular clearance and the rate can be preselected by varying the thickness of lower closure element 138. The same advantages in savings are appreciated in a lash adjuster of the overhead cam type as in the hydraulic and mechanical tappets described previously with regard to FIGS. l-6.

As a result of the foregoing, an important aspect of this invention is the provision of a closure element comprising an upper and lower part, with the lower part being capable of determining the meter rate by either varying its thickness or its diameter. The construction of the upper and lower parts can be utilized in a variety of existing and proposed tappet and lash adjuster assemblies without varying the overall tappet or adjuster configuration. The utilization of a two-part closure element greatly reduces the amount of high tolerance machining required over existing proposals and in fact, permits the utilization of a less expensive material such as heat sintered and treated metal. In addition, it eliminates the necessity of an additional internal groove in the tappet or adjuster body configuration of hydraulic tappets or adjusters thereby further reducing the overall cost structure.

Although several embodiments have been shown and described in detail, it will be obvious to those having ordinary skill in this art that the details of construction of this particular embodiment may be modified in a great many ways without departing from the unique concepts presented. It is therefore intended that the invention is limited only by the scope of the appended claims rather than by particular details of construction shown, except as specifically stated in the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a hydraulic lash adjuster adapted for cooperative association with a rocker arm and including an adjuster body having an oil reservoir; a closure means positioned within said adjuster body, said closure means having a passageway adapted for communication with said associated rocker arm and means for metering oil conducted from said reservoir to said arm; the improvement comprising: said closure means being formed of an upper and lower part which are maintained in constant engagement with each other; said upper part includes a fulcrum ball operatively engaged with a ro ckerarm and having an opening extending from its upper surface to-at least the upper surface of said lower part;-and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot-.extending from said opening to the space about said closure means; said=opening and said slot forming the said passageway adapted for communication with said rocker arm. a

2; In a hydraulic lash adjuster adapted for operative connection to a rocker arm havinga body; a plunger reciprocal in said' body, said plunger having a cavity defining an oil reservoir; oil inlet means communicating with said oil reservoir; a closuremeans clo'sin'g said cavity and adapted for engagement with-said rocker arm; oil outlet means communicating with said oil reservoir; and means for metering oil conducted from said reservoir through said outlet means; the improvement comprising: said closure means being formed of an upper and lower part which are maintained in constant engagement with each other; said upper part having a head engageable with said rocker arm and an opening extending from said head to at least the upper surface of said lower part; and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot extending from said opening to the space between said closure means and inner wall of one of said adjuster body and plunger; said opening and said slot forming at least a portion of said outlet means.

3. The improvement as defined in claim 2 wherein the upper end of said plunger defines a shoulder on which the lower part of said closure means is seated, said lower surface of said lower part being in contact with said shoulder, a second slot in one of said engaging surfaces between said shoulder and lower part, said second slot extending from the space between said closure means and said inner wall of said adjuster body providing an annular path between at least a portion of the outer wall of said lower part and the inner wall of said adjuster body, said slots, annular path and opening providing a means for oil to communicate from said reservoir to said opening, at least one of said slots and annular path defining a restricted flow means to provide said metering means.

4. The improvement as defined in claim 3 wherein the cross-sectional flow area of said annular path is less than each of said slots and opening so that said annular path provides said metering means.

5. The improvement as defined in claim 4 wherein the rate of said metering is determined by preselecting the thickness of said lower part of said closure means.

6. The improvement as defined in claim 4 wherein the rate of said metering is determined by preselecting the diameter of said lower part of said closure element.

7. The improvement as defined in claim 3 wherein the cross-sectional area of the clearance between the inner wall of said adjuster body and the outer wall of said upper part of said closure means is substantially less than any cross-sectional area of said slots, annular path and opening so that said metered oil will flow freely through said outlet means to said rocker arm.

8. A hydraulic lash adjuster comprising, in combination: an adjuster body having an internal cavity, the upper end of which is open; a hollow plunger positioned within said cavity, the upper end of which is open, said hollow plunger defining an oil reservoir; a closure element separate fro'iii and plunger and supported by said pltliigei wi'tliiii iild cavity closing the open end of said adjuster body, said closure element being formed of an upper and lower part, said upper part having a fulcrum ball engageable with a rocker arm seat and an opening extending from said rocker arm seat engaging surface to at least the upper surface of said lower part, and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot extending from said opening to the space between the closure element and inner wall of one of said plunger and adjuster body, the upper end of said plunger including a support surface for said closure element, said support surface including one or more grooves extending from the space between said lower part and inner wall of said adjuster body to at least the point in communication with said reservoir, said slot. space and groove providing a means for oil to communicate from said reservoir to said opening; and means for metering the rate of oil flow to said opening, one of said slot and space defining a restricted flow means to provide said metering means.

9. The combination according to claim 8 wherein said one or more grooves are comprised of a plurality of circumferentially spaced radially projecting grooves.

10. The combination according to claim 9 wherein at least a pair of said circumferentially spaced grooves are in diametrical alignment.

11. The combination according to claim 8 wherein said grooves are convergent toward the center of said plunger, the cross section of which is a maximum at said space between said seat and inner wall.

Claims

1. In a hydraulic lash adjuster adapted for cooperative association with a rocker arm and including an adjuster body having an oil reservoir; a closure means positioned within said adjuster body, said closure means having a passageway adapted for communication with said associated rocker arm and means for metering oil conducted from said reservoir to said arm; the improvement comprising: said closure means being formed of an upper and lower part which are maintained in constant engagement with each other; said upper part includes a fulcrum ball operatively engaged with a rocker arm and having an opening extending from its upper surface to at least the upper surface of said lower part; and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot extending from said opening to the space about said closure means; said opening and said slot forming the said passageway adapted for communication with said rocker arm.

2. In a hydraulic lash adjuster adapted for operative connection to a rocker arm having a body; a plunger reciprocal in said body, said plunger having a cavity defining an oil reservoir; oil inlet means communicating with said oil reservoir; a closure means closing said cavity and adapted for engagement with said rocker arm; oil outlet means communicating with said oil reservoir; and means for metering oil conducted from said reservoir through said outlet means; the improvement comprising: said closure means being formed of an upper and lower part which are maintained in constant engagement with each other; said upper part having a head engageable with said rocker arm and an opening extending from said head to at least the upper surface of said lower part; and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot extending from said opening to the space between said closure means and inner wall of one of said adjuster body and plunger; said opening and said slot forming at least a portion of said outlet means.

8. A hydraulic lash adjuster comprising, in combination: an adjuster body having an inTernal cavity, the upper end of which is open; a hollow plunger positioned within said cavity, the upper end of which is open, said hollow plunger defining an oil reservoir; a closure element separate from said plunger and supported by said plunger within said cavity closing the open end of said adjuster body, said closure element being formed of an upper and lower part, said upper part having a fulcrum ball engageable with a rocker arm seat and an opening extending from said rocker arm seat engaging surface to at least the upper surface of said lower part, and a slot formed in at least one of the surfaces of engagement between said upper and lower parts, said slot extending from said opening to the space between the closure element and inner wall of one of said plunger and adjuster body, the upper end of said plunger including a support surface for said closure element, said support surface including one or more grooves extending from the space between said lower part and inner wall of said adjuster body to at least the point in communication with said reservoir, said slot, space and groove providing a means for oil to communicate from said reservoir to said opening; and means for metering the rate of oil flow to said opening, one of said slot and space defining a restricted flow means to provide said metering means.