Hydraulic lash adjuster

A hydraulic lash adjuster assembly constructed in accordance to one example of the present disclosure includes a bucket and a hydraulic lash adjuster. The hydraulic lash adjuster is received in the bucket and has a body, a leakdown plunger and a socket. The leakdown plunger is received in the body. The socket is received by the leakdown plunger. The socket and leakdown plunger define a reservoir therebetween. The socket includes a gravity feed arrangement to feed fluid to the reservoir of the leakdown plunger.

FIELD

The present disclosure is directed to a hydraulic or mechanical lash adjuster.

BACKGROUND

Hydraulic or mechanical lash adjusters for internal combustion engines have been in use for many years to eliminate clearance or lash between engine valve train components under varying operating conditions. Lash adjusters can maintain efficiency and reduce noise and wear in the valve train. In some examples, hydraulic lash adjusters can support the transfer of energy from the valve-actuating cam to the valves through hydraulic fluid trapped in a pressure chamber under the plunger.

SUMMARY

A hydraulic lash adjuster assembly constructed in accordance to one example of the present disclosure includes a bucket and a hydraulic lash adjuster. The hydraulic lash adjuster is received in the bucket and has a body, a leakdown plunger and a socket. The leakdown plunger is received in the body. The socket is received by the leakdown plunger. The socket and leakdown plunger define a reservoir therebetween. The socket includes a gravity feed arrangement to feed fluid to the reservoir of the leakdown plunger.

According to other features, the socket comprises a top surface, a bottom surface and an intermediate shoulder surface. The intermediate shoulder surface abuts the leakdown plunger. The gravity feed arrangement comprises at least one aperture defined through the socket. The at least one aperture comprises a first pair of apertures that lead to a second pair of apertures. The apertures of the second pair of apertures are offset from the apertures of the first pair. The second pair of apertures provide a surface tension seal to the top surface of the leakdown plunger and route fluid into the reservoir.

According to additional feature, the leakdown plunger defines a recirculation passageway including an annular notch portion and an aperture portion. The socket can be enclosed in the bucket. A push tube guide can enclose the socket within the bucket.

A hydraulic lash adjuster assembly constructed in accordance to other features of the present disclosure can include a bucket and a hydraulic lash adjuster received in the bucket. The hydraulic lash adjuster can have a body, a leakdown plunger and a socket assembly. The leakdown plunger can be received in the body. The socket assembly can be received by the leakdown plunger. The socket assembly and leakdown plunger can define a reservoir therebetween. The socket assembly can include a socket and a valve member. The socket can include a valve seat and a valve restraint. The valve member can move relative to the socket. The valve member can engage the valve restraint in a first orientation and engage the valve seat in a second orientation. Fluid is permitted to flow between the valve member and the valve restraint in the first orientation. Fluid is precluded from flowing between the valve member and the valve seat in the second orientation.

According to other features, the valve member can comprise a plate. The valve member can be captured in the socket by the valve restraint. The valve restraint can include a shelf. In one configuration the shelf can be non-flat. In another configuration the shelf can be irregular shaped. In an alternate configuration the valve restraint comprises fingers. The fingers can be radially offset relative to each other.

A hydraulic lash adjuster assembly constructed in accordance to other features of the present disclosure can include a hydraulic lash adjuster having a body, a leakdown plunger and a socket assembly. The leakdown plunger can be received in the body. The socket assembly can be received by the leakdown plunger. The socket assembly and leakdown plunger can define a reservoir therebetween. The socket assembly can include a socket and a valve member. The socket can include a valve seat and a valve restraint. The valve member can be captured by a valve restraint mounted in the socket. The valve member can move relative to the socket. The valve member can engage the valve restraint in a first orientation and engage the valve seat in a second orientation. Fluid is permitted to flow between the valve member and the valve restraint in the first orientation. Fluid is precluded from flowing between the valve member and the valve seat in the second orientation.

According to other features the hydraulic lash adjuster can further include a bucket. The hydraulic lash adjuster can be received in the bucket. The valve member can comprise a ball. The valve restraint can comprise a cage. The cage can define passages therein.

DETAILED DESCRIPTION

A plurality of different examples of the present teachings is shown in the Figures of the application. Similar features are shown in the various aspects of the present disclosure. Similar features have been numbered with a common reference numeral and have been differentiated by an alphabetic suffix. Also, to enhance consistency, the structures in any particular drawing share the same alphabetic suffix even if a particular feature is shown in less than all of the disclosed aspects of the present teachings. Similar features are structured similarly, operate similarly, and/or have the same function unless otherwise indicated by the drawings or this specification. Furthermore, particular features of one example can replace corresponding features in another example or can supplement other examples unless otherwise indicated by the drawings or this specification.

In some operating environments, it may be desirable to install hydraulic lash adjusters into a dry engine block and in subsequent assembly operations invert the engine for an extended period. In existing hydraulic lash adjusters, at least some of the oil in a reservoir of the hydraulic lash adjuster would leak out. Further, once the engine is fully assembled and started, the high pressure chamber may ingest the air from the reservoir and several minutes (twenty or more) may pass before the high pressure chamber refills with oil. Using a biased, normally-open check valve would allow quicker filling as the normally-open valve arrangement pumps up more quickly than a normally-closed arrangement.

The normally-open valve arrangement also allows for shipping the hydraulic lash adjuster with the reservoir empty. Since the normally-open valve arrangement dispels an amount of fluid or air with each stroke, it allows for shipping the hydraulic lash adjuster with the reservoir empty. Any air that is ingested to the high pressure chamber will more naturally be pumped out with far fewer strokes. It will be appreciated in light of the disclosure that it can be shown that this phenomenon can be optimized by placing the normally open check valve as high in the high pressure chamber as possible.FIGS. 1-3illustrate a hydraulic lash adjuster having a recirculation passageway to allow for passage of fluid from a high pressure chamber to the reservoir to more quickly fill the reservoir.

Referring now toFIGS. 1-4, a hydraulic lash adjuster assembly10can include a bucket12and a hydraulic lash adjuster14. The hydraulic lash adjuster14can be received in the bucket12. The hydraulic lash adjuster14can include a body16, a leakdown plunger18, and socket20. The leakdown plunger18can be received in the body16. A high pressure chamber22can be defined between the body16and the leakdown plunger18. A reservoir24can be defined between leak down plunger18and the socket20. The socket20can substantially close the reservoir24and can itself be enclosed in the bucket12with a push tube guide42or clip.

A spring26can be disposed in the high pressure chamber22. The spring26can bias the body16and the leakdown plunger18apart along a central axis28of the assembly10. The extent of relative travel between the leakdown plunger18and the body16is referenced at30.

A normally-open valve arrangement32can be mounted to the leakdown plunger18. The normally-open valve arrangement32can be positioned between the high pressure chamber22and the reservoir24. The normally-open valve arrangement32can include a ball or valve member34, a spring36, and a retainer38. The leakdown plunger18can define a valve seat40. The spring36can urge the valve member34toward the high pressure chamber22and against the retainer38. A predetermined level of differential pressure between high pressure chamber22and reservoir24can urge the valve member34toward the reservoir24, overcoming the spring36, and seating the valve member34on the valve seat40.

A recirculation passageway44can be defined by the leakdown plunger18. The recirculation passageway44assists the assembly10to pump up from dry or spongy more quickly by returning any oil pumped out of the high pressure chamber22to the reservoir24. The recirculation passageway44can include an annular notch portion46formed in an outer surface of the leakdown plunger18. The recirculation passageway44can also include an aperture portion48extending through the leakdown plunger18. In operation, fluid can pass between the outside surface of the leakdown plunger18and an inside surface of the body16, collect in the annular notch portion46, and pass into the reservoir24through the aperture portion48. The recirculation passageway44allows the assembly10to pump up from dry or spongy relatively quickly.

FIG. 5illustrates an alternative socket20aaccording to the present disclosure. The socket20acan be incorporated into a hydraulic lash adjuster assembly such as the hydraulic lash adjuster assembly10described herein. The socket20aextends between a top surface50a, a bottom surface52aand an intermediate shoulder surface53a. The intermediate shoulder surface53acan abut a leakdown plunger. The socket20aincludes a gravity feed arrangement to feed fluid to a reservoir of the leakdown plunger. The gravity feed arrangement includes apertures54a,56a,58a,60a.

Two apertures54aand56alead to machined apertures58a,60athat are offset to provide a surface tension seal to the top of the leakdown plunger and route fluid into the reservoir. Vent indentations can be defined in the socket20ato vent out any air in the reservoir as fluid fills the reservoir. This would provide a “flow through” design such that any soot or other contaminate would not accumulate. The socket20adepicted inFIGS. 4 and 5can be a manner to gravity feed oil from the outer diameter of a push tube and/or rocker arm (not shown) down into the reservoir leakdown plunger. The result would be a hydraulic lash adjuster assembly that would not need a pressure feed to it to keep it full, thereby reducing the demand on the oil pump.

FIGS. 6-8illustrate alternative socket assemblies62b,62c, and62dthat can prevent fluid from draining from a reservoir if the engine is inverted for an extended period. As shown inFIG. 6, a socket assembly62bcan include a socket20band a valve member or plate64b. The socket20bcan define a valve seat66b. The socket20bcan also define a valve restraint or fingers68b. The fingers68bare at least one of radially offset from each other, irregular shape and non-flat.FIG. 6illustrates the position of the valve member64bwhen the engine is not inverted. When non-inverted or right side up, fluid is permitted to flow between the plate64band the fingers68b. Explained further, the irregular shape of the fingers68bdoes not allow a seal to be achieved between the plate64band the fingers68b. Other configurations or geometries are contemplated for permitting fluid flow in one direction while inhibiting flow in an opposite direction. The valve member64bcan be captured by the valve restraint68b. When the engine is inverted, the valve member64bcan be induced by gravity to seat against the valve seat66band inhibit fluid from escaping the reservoir.

FIG. 7illustrates a socket assembly62chaving a socket20cand a valve member or plate64c. The socket20ccan define a valve seat66c. The illustrated position of the valve member64cis between the position when the engine is not inverted and the position when the engine is inverted. The valve member64ccan be captured by a valve restraint or shelf70cdefined by the leakdown plunger18c. When the engine is inverted, the valve member64ccan be induced by gravity to seat against the valve seat66cand prevent fluid from escaping the reservoir24c. When the engine is non-inverted or right side up, fluid is permitted to flow between the plate64cand the shelf70c. Explained further, the irregular or non-flat shape of the shelf70cdoes not allow a seal to be achieved between the plate64cand the shelf70c.

FIG. 8illustrates a socket assembly62dhaving a socket20dand a valve member64d. The socket20dcan define a valve seat66d. The valve member64dcan be captured by a valve restraint68dmounted on the socket20d. The valve member64dcan be a ball. The valve restraint68dcan be a cage having passages80therethrough. The illustrated position of the valve member64dis between the position when the engine is not inverted and the position when the engine is inverted. When the engine is inverted, the valve member64dcan be induced by gravity to seat against the valve seat66dand prevent fluid from escaping the reservoir. When non-inverted or right side up, fluid is permitted to flow around the valve member64dand through the passages80in the cage of the valve restraint68d.

FIGS. 9-11illustrate an assembly110that includes a socket120received in a body112. The socket120can include similar features as any of the sockets20a,20b,20cand20ddescribed above. In the configuration shown inFIGS. 9-11, the body112extends up around the socket120and is retained with a C-clip122. Other retention methods may be used. The same gravity feed features described above may be incorporated into the configuration shown inFIGS. 9-11.

The foregoing description of the aspects of the present teachings has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to those particular aspects, but, where applicable, are interchangeable and can be used in a selected examples, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.