JPS58113511A - Hydraulic lash adjuster - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to hydraulic lash adjusters of the type used in internal combustion engines, and more particularly to hydraulic lash adjusters which operate in a substantially upright position and are not supplied with pressurized oil.

The principal object of the present invention is a hydraulic lash adjuster of the above type in which the outer surface of the lash adjuster plunger is provided with an oil recirculation groove for returning oil to the internal supply chamber of the -C lash adjuster.

Another object is a lash adjuster of the type described above which allows oil to pass from the outer surface of the lash adjuster through an opening in the plunger and into the interior of the lash adjuster.

Another object is a lash adjuster of the above type that includes a filter to prevent contaminants from entering the interior of the lash adjuster plunger.

Another object is to provide a lash adjuster of the type described above which includes a pair of spaced apart oil recirculation grooves on the outer surface of the plunger to prevent leakage of oil from the internal supply chamber of the lash adjuster.

Another object is a lash adjuster of the type described above, which utilizes oil used in other engine valve train components to replenish the lash adjuster.

Other objects will become apparent from the specification, drawings, and claims.

Hereinafter, the present invention will be explained with reference to the drawings.

Hydraulic tappets and hydraulic valve lifters all perform lash adjustment functions. As shown in Figures 4 and 5, there are engine valve train components that only adjust lash and do not perform a valve lift function. The term "lash adjuster" as used herein refers to all such devices, including devices that are part of the valve train but do not perform a lash adjustment function, as well as devices that perform valve lift or tappet functions. Contains.

U.S. Pat. No. 4,184,464 shows a hydraulic lash adjuster that operates in either vertical or horizontal positions and is essentially a pressurized unit supplied with pressurized oil. The lash adjuster is equipped with an oil recirculation groove device to ensure that oil leaking from the high pressure chamber is returned to the interior of the plunger. The present application is particularly directed to a hydraulic lash adjuster that operates in an upright position and is not pressurized.

There is no means to introduce pressurized oil directly into the lash adjuster as in the above-mentioned US patent. The lash adjuster has a supply chamber oil that is supplemented with oil obtained from the corresponding engine valve train component. A filter is provided to prevent contaminants from entering the lash adjuster. In some applications, a check valve may be provided to prevent oil loss. An oil recirculation groove arrangement on the outer surface of the plunger includes a pair of spaced apart grooves for returning oil leaking between the outer surface of the plunger and the interior of the lash adjuster to the supply chamber. It is important to return any oil that leaks from the high pressure chamber of the lash adjuster to it. It is also important to provide a source of replenishment for the lash adjuster reservoir, and this is accomplished through an opening in the tip of the lash adjuster that is adapted to receive oil from the engine valve train components. This opening at the tip of the lash adjuster acts as a vent to accommodate oil expansion during engine temperature rises.

In the constructions of Figures 1, 2, and 6, the engine camshaft is shown at 10, with the cam nose 12 shown in contact with the closed end of the hydraulic lash adjuster 14. The opposite end of the lash adjuster 14 is in contact with a bushing rod 16 whose upper end is in contact with the underside of the rocker arm. As before, the opposite end of the rocker arm pushes against a valve 20 which controls the intake and exhaust air through the opening 22 of the cylinder 24. The invention particularly relates to a lash adjuster 14 that compensates for lash or clearance in a valve train, as is well known.

Lash adjusters are exposed to extreme operating conditions. In normal life, the lash adjuster is approximately 15
The driver will ride on the corresponding cam surface for more than 1.5 billion revolutions, which is equivalent to a straight-line distance of 000 miles (24,000 KM). Lash adjuster is 1800 pounds (
At 816? ) under a load exceeding -40°F (-40C
) to 300°F (149C). The lash adjuster operates under these conditions and must maintain zero lash or clearance between all components of the engine valve train. The lash adjuster is a delicately designed, expertly crafted engine component that is surprisingly easy to maintain.

12Figure 1. ! With particular attention to the structure of FIG. 3, the lash adjuster includes a body 26 having a closed end 28. As shown in FIG. The body 26 is provided with a chamber 30 in which a plunger assembly 32 is mounted. The plunger assembly includes an inner plunger member 34 and a plunger cap 6.
Consists of 6.

A high pressure chamber 58 is formed between the closed end 28 of the body 26 and the plunger member 34.

A conventional plunger spring 40 is located within the high pressure chamber 38, which normally pushes the plunger assembly out of the lash adjuster. A flow passageway 42 is formed at the inner end of the plunger assembly 62, and a check valve 44 controls the flow of fluid through the flow passageway 42 to the high pressure chamber. This check valve 44 can be biased into the flow path closed position by a small coil spring 46 held in place by a retainer 48. The above structure is mostly conventional.

A retainer 50 is installed at the open end of the body to prevent the plunger from coming off from inside the body. Plunger cap 36 has a generally spherical socket 52 which receives a bushing rod as shown in FIG. Socket 52 is provided with an opening 54 that provides a means for channeling oil or hydraulic fluid used in the bushing rod or associated valve train component into the interior of plunger assembly 32. A filter 56 is held in place within plunger cap 36 to control fluid flow through opening 54 . This filter, which can be made of compressed wire mesh, sintered bronze, or other suitable material, allows oil to enter the interior of the plunger, but also removes dirt and debris that may be present on the engine valve train components. It is designed to prevent any other form of sediment from entering the inside of the lash adjuster.

Additionally, in the configuration of Figures 1-6, there is reciprocating movement of the lash adjuster body and plunger, so the filter also prevents oil from being thrown away from the assembly.

The lash adjusters shown in Figures 1 to 6 operate in a substantially upright or vertical position.

This lash adjuster is not pressurized because it is not normally supplied with pressurized oil.

If fluid is lost from the lash adjuster, it can be replenished through the opening 54 described above. An oil recirculation groove system is provided on the outer surface of the plunger to minimize leakage from the lash adjuster. Typically, the outer surface of the plunger and the inner surface of the body have mating surfaces that are machined into intimate contact. However, oil may settle on the outer surface of the plunger and leak, so an oil recirculation ms8 of the fang 1 is provided at the connection between the plunger member 34 and the plunger cap 36. Two openings 60 on either side of the plunger allow the oil in the groove 58 to return to the interior of the plunger and, if necessary, to open the reverse valve 44 to the high pressure chamber. The oil recirculation groove of spear 2 is shown at 62, which is generally adjacent filter 56, but is not limited thereto. one or more openings 6
4 may connect the groove 62 with the interior of the plunger.

The structure shown in Figure 1 is that of an ordinary ■8 engine.

The engine structure shown in Figure 4I is known as an overhead cam type engine, with a finger follower'
66 is used to transmit movement from cam 68 to valve 70 of the engine. The lash adjuster is shown at 72 and does not have the body movement of the lash adjuster 14 having the structure shown in Figure 1.

Rather, the body of the lash adjuster 72 in FIG. 4 remains in a nearly constant position, and as the cam rotates, the plunger reciprocates slightly, causing a corresponding movement of the valve 70.

With particular attention to the structure of the overhead cam engine lash adjuster 72 of FIG. 4, shown in FIG. 5, the lash adjuster body 74 has a closed end 76 and an interior chamber 78. Plunger member 82 and plunger cap 84
A plunger assembly 80 consisting of a plunger assembly 80 is installed within this body. The high pressure chamber is indicated at 86 and has the same reverse valve and spring as shown in Figure 6, with like numbers indicating like parts.

Plunging calf 84 has a nose 88 that projects outwardly through the open end of the body and has an opening 90 that comes into contact with finger follower 66. In this regard, it is noted that the finger follower 66 has a small opening 92 which provides a means for providing lubricant to the opening 90 on the finger follower, camshaft and corresponding components. Although oil is not intentionally or continuously fed through the plunger opening, oil inside the plunger can be used if proper fluid delivery into the lash adjuster is required. .

As previously mentioned, the plunger cap 84 is provided with a filter 94.

Two oil recirculation grooves are formed on the outer surface of the plunger. The groove 96 of the spear 1 is located at the connection between the plunger member 82 and the plunger cap 84, and is provided with a pair of openings I98 connecting this groove with the interior of the plunger.The groove 100 of the fang 2 is separated from the groove 96. , there may be one or more openings 102 leading into the interior of the plunger.

The lash adjuster shown in Figure 5 operates in the same manner as the lash adjusters shown in Figures 2 and 3 due to the advantages mentioned above.

The operational differences result from the fact that the lash adjusters are used in different engine environments.

In the structures shown in Figures 6, 7, and 8, the lash adjuster 104 rides on a cam 106, and the upper end of this lash adjuster is in contact with a rocker arm 108. The opposite end of the rocker arm is in contact with valve 110.

Although the structure of Figure 6 is more compact than the structure shown in Figure 1, the relationships among the valves, rocker arms, lash adjusters, and cams are shown similarly.

In Figure 7, the lash adjuster body is indicated at 112 and the plunger assembly is indicated at 114.

The plunger assembly includes a plunger cap 116 and a plunger member 118. A flow passage 120 is provided at the closed inner end of the plunger, and this flow passage is connected to the high pressure fluid chamber 1.
It is adapted to control the fluid entering 22. Check valve 1
24 is held in place by a small coil spring 126 positioned by a retainer 128. The plunger spring is indicated at 130.

The outer end of the plunger has a small opening 152 to direct oil to filter 134 supported by plunger cap 116. Aperture 132 and filter 134 function in the same manner as previously described. However, it should be noted that this opening 132 is not located in the center of the plunger cap, but is located at an angle.

■A die-shaped check valve 156 having a notch 135 (see Figure 8) is installed on a shoulder 137 provided on the plunger member, and therefore the check valve is installed inside the filter 154. become.

The outer surface of the plunger has an oil recirculation groove 166 of the fang 1 with an opening 168 which controls the flow of oil from this groove into the interior of the plunger. The oil recirculation groove of spear 2 is shown at 140, the opening 142 of which allows fluid in the groove to flow into the interior of the plunger.

The structures shown in Figures 6, 7, and 8 operate in the same manner as the devices shown in Figures 4, 5, and 1 to 3. The body of the lash adjuster itself is Cam 106.
It operates in a manner very similar to that of the structure shown in Figures 1 to 3 in that it moves as the blade rotates.

Check valve 133 would normally only be used within a valve lifter structure. In the actuation cycle, the valve lifter rises to the top of lift determined by the cam profile. At the same time, the oil in the lifter chamber will move.

When the lifter then begins to descend, the oil within it still continues to rise. The ever-increasing oil pressure causes the check valve to seat on the plunger cap, preventing oil from being thrown out of the lash adjuster. A small notch 165 allows oil to flow into the interior of the plunger.

One advantage of the plunger being open at one end is that it provides a means of allowing oil to flow into the interior of the plunger to supply oil that is lost from the high pressure chamber. Also, air within the plunger can escape through an opening in the outer end. Additionally, the open end of the plunger provides a means for expanding the oil within the lash adjuster in response to increases in engine operating temperature.Although the present invention has been described in connection with a gasoline engine, it is equally applicable to diesel engines. While the preferred embodiments of the invention have been illustrated and described, it will be understood that many changes and modifications may be made thereto.

[Brief explanation of the drawing]

Figure 1 is a partial view of the internal combustion engine showing the components of the engine valve train, Figure 2 is a top view of the lash adjuster used in the structure of Figure 1, and Figure 6 is the 5-5 diagram in Figure 2. Figure 4 is a cross-sectional view taken along plane 6, and Figure 4 is a diagram similar to Figure 1 showing another form of the valve train of an internal combustion engine, and Figure 5 is a lash diagram used in the engine structure of Figure 4. Fig. 6 is an enlarged axial sectional view of the adjuster; Fig. 6 is a diagram similar to Fig. 1 and Fig. 4, showing components corresponding to another form of internal combustion engine valve train; Fig. 7; Fig. 7; is an enlarged axial sectional view through the lash adjuster used in the engine shown in Figure 6, and Figure 8 is a plan view of a check valve used in the lash adjuster shown in Figure 7. [Explanation of symbols of main parts]

Claims (1)

[Scope of Claims] 1. A hydraulic lash-7 diaster for use as a valve train component of an engine and operating in an essentially upright position, comprising a generally cylindrical body having a closed end, an internal chamber, and an open end; , a hollow plunger installed in the inner chamber, a high-pressure fluid pressure chamber is formed between the closed end of the body and the plunger, and a plunger spring is installed in the high-pressure fluid pressure chamber. 1. the plunger has a closed inner end and a flow path; A valve member is provided for controlling fluid flowing through the closed inner end of the plunger and the flow path to the high pressure fluid pressure chamber, and the plunger has an inner chamber connected to the flow path and an opening provided at an outer end thereof. and adapted to allow external fluid to flow into the internal chamber of the plunger,
A filter is disposed within the plunger between the opening and the internal chamber, and an external fluid circulation groove device is formed on the outer surface of the plunger, which communicates with the interior of the plunger and is in contact with the outer surface of the plunger. A hydraulic lash adjuster characterized in that the fluid flowing between the body and the body is returned to the plunger internal chamber and the flow is returned to the high pressure fluid pressure chamber. 2. The lash adjuster according to claim 1, wherein the external fluid circulation groove device includes two spaced apart circumferential grooves provided on the outer surface of the plunger, and the opening penetrating the side wall of the plunger includes two circumferential grooves provided on the outer surface of the plunger. A lash adjuster characterized in that each of the lash adjusters is connected to the inside of the plunger internal chamber. 3. A lash adjuster according to claim 1, wherein the plunger is in the form of an assembly including an inner plunger member and an outer plunger cap. 4. The lash adjuster according to claim 6, wherein one of the fluid recirculation grooves is formed in a connection between the plunger member and the plunger shaft. 5. The lash adjuster according to claim 3, wherein the filter is supported by the plunger cap. 6. The lash adjuster according to claim 1, wherein a check valve is provided in the plunger chamber 7 and adjacent to the filter.