JP2528009Y2 - Hydraulic lash adjuster for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hydraulic lash adjuster for eliminating valve clearance of an internal combustion engine.

[Prior Art] Conventionally, such a hydraulic lash adjuster is disclosed in
What is described in 61-237807 is known.

This includes a bottomed cylinder, and a plunger that slides on the inner peripheral surface of the cylinder to define a hydraulic chamber at the bottom and has an upper end as an operating end. An oil reservoir that communicates with an external oil supply passage via the oil supply hole, and a valve hole that communicates the oil reservoir with the above-described hydraulic chamber are provided. The hydraulic chamber contains a check valve that opens and closes a valve hole in response to pressure reduction and pressure increase in the hydraulic chamber, and an extrusion spring that urges the plunger in the extension direction. The oil reservoir is partitioned into an inner chamber connected to the valve hole, and an outer chamber surrounding the inner chamber and connected to the oil supply hole, and a partition wall is provided in the plunger for communicating the two chambers near the working end. ing.

[Problem to be Solved by the Invention] However, in such a conventional example, the inner chamber is always in communication with the outer chamber at the upper end edge of the partition provided in the plunger. Can only store oil up to the height of the top edge of the. Therefore, for example, when a lash adjuster must be used with an inclination such as a V-type or horizontally opposed engine,
If the engine is stopped for a long period of time, the oil stored in the inner chamber will flow out to the outer chamber and the amount of oil in the inner chamber will decrease.When the engine is restarted in this state, air will flow from the oil chamber to the high-pressure hydraulic chamber. There was a problem that it was sucked in and the function of the lash adjuster was impaired.

If this problem is to be avoided, the partition wall must be formed high, and the overall height of the lash adjuster increases, resulting in an increase in the size of the apparatus.

The purpose of the present invention is to pay attention to such a conventional problem, and to prevent the stored oil from flowing out from the inner chamber even when the engine is stopped for a long period of time. It is an object of the present invention to provide a hydraulic lash adjuster for an internal combustion engine that does not impair the performance.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylinder having a bottom and a hydraulic chamber at the bottom which slides on the inner peripheral surface of the cylinder and has an upper end exposed to the atmosphere. A plunger serving as an operating end that opens, the plunger being provided with an oil reservoir that communicates with an external oil supply path, and a valve hole that communicates the oil reservoir with the hydraulic chamber. A check valve that opens and closes a hole, and a return spring that urges the plunger in the extension direction are housed therein, and the oil reservoir is an inner chamber that communicates with the valve hole, and an outer that surrounds the inner chamber and communicates with the oil supply passage. In a hydraulic lash adjuster for an in-line or V-type internal combustion engine, a partition is provided for partitioning the internal chamber from the chamber, and the upper part of the partition has an opening and the opening communicates with the inner chamber and the outer chamber. Sometimes the inside chamber and the outside The partition is provided with an opening / closing member that opens the opening when the engine is operating and connects the inner chamber and the outer chamber, with an opening between the chamber and the opening.

[Operation] According to the present invention, a partition is provided to partition the inner chamber and the outer chamber, and an opening / closing member is provided to separate the inner chamber and the outer chamber when the engine is stopped and to connect the two chambers when the engine is operating. .

Therefore, when the engine is stopped, the opening is closed by the weight of the opening / closing member and the surface tension of the oil, the outflow of the stored oil from the inner chamber to the outer chamber is prevented, and no air is sucked into the hydraulic chamber.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

 1 to 3 show an embodiment of the present invention.

First, in FIG. 1, reference numeral 1 denotes a cylinder head, 2 denotes a rocker arm provided with rollers 3, 4 denotes an intake valve or an exhaust valve, 5 denotes a cam, and 10 denotes a hydraulic lash adjuster according to the present invention. is there. The hydraulic lash adjuster 10 is mounted at an angle α to the perpendicular VL.

The hydraulic lash adjuster 10 has a bottomed cylinder 11 and
The hydraulic chamber 12 slides on the inner peripheral surface of the cylinder 11 and
The main component is the plunger 13 that defines
The cylinder 11 is fitted into the support hole 1A of the cylinder head 1. The plunger 13 engages the outer hemispherical working end 13A with the hemispherical recess 2A at the base end of the rocker arm 2 to support the rocker arm 2. The plunger 13 has an oil reservoir 14 and a valve hole 15 communicating the oil reservoir 14 with the hydraulic chamber 12. The oil reservoir 14 communicates with an oil supply passage 18 formed in the cylinder head 1 through an oil supply hole 16 in the side wall of the plunger 13 and an oil supply hole 17 in the side wall of the cylinder 11, and an oil pump through the oil supply passage 18. It is filled with oil supplied from.

A hat-shaped valve cage 19 is fitted to one end of the plunger 13, and the valve cage 19 accommodates a spherical check valve 20 for opening and closing the valve hole 15 and a relief spring 21 for urging the valve in a valve closing direction. Is done. Check valve 20
Open when the hydraulic chamber 12 is depressurized and close when the pressure is increased. Further, a return spring 22 for urging the plunger 13 in the extension direction is accommodated in the hydraulic chamber 12.

A cylindrical partition wall 23 is provided on the inner peripheral wall of the plunger 13 so as to protrude from directly below the oil supply hole 16 and extend to the vicinity of the working end 13A, and open there. The oil reservoir chamber 14 is partitioned by the partition wall 23 into an inner chamber 14B and an outer chamber 14A connected to the valve hole 15, and the inner chamber 14B and the outer chamber 14A communicate with each other through an opening 14C at an upper portion.

Further, the both chambers 14A and 14B are provided with a cap-shaped head plunger 24 movably provided in the partition wall 23 so as to be located between the end face of the partition wall 23 on the working end 13A side and the inner side surface 13B of the plunger 13. The head plunger 24 has an opening 14C of the partition wall 23.
During operation of the engine, the inner chamber 14B and the outer chamber 14A communicate with each other, and when the engine is stopped, the opening 14A is closed to close the inner chamber 14B and the outer chamber 14A.
A is separated from A.

A radial groove 13C is formed on the inner side surface 13B of the plunger 13, and when the head plunger 24 comes into contact with the inner side surface 13B of the plunger 13 by hydraulic pressure from the oil supply passage 18 during operation of the engine, the plunger operating end is closed. The flow rate discharged from the air vent hole 13D formed at the bottom is controlled.

The plunger 13 having such a partition 23 is divided into an upper half 13E having an outer chamber 14A and a lower half 13F having an inner chamber 14B to facilitate its manufacture. Partition
23 is manufactured separately from the lower half 13F of the plunger 13 and the upper half 1
Press fit into 3E.

Further, as shown in FIGS. 2 and 3, a notch groove 24A is formed in the side wall portion of the head plunger 24 so as to form an oil passage between the upper end surface of the partition wall 23 when the head plunger 24 is lifted. Have been.

 Next, the operation of this embodiment having the above configuration will be described.

When the cam 5 presses the rocker arm 2 and lifts the intake valve or the exhaust valve 4, a pressing force is applied from the rocker arm 2 to the plunger 13, but the check valve 20 keeps the valve closed, so that hydraulic pressure is generated in the hydraulic chamber 12. Then, the movement of the plunger 13 is prevented by the hydraulic pressure, and the rocker arm 2 is moved.
The base end is supported. As a result, the rocker arm 2 swings around the operating end 13A of the plunger 13 to open and close the intake valve or the exhaust valve 4. During this time, the oil in the hydraulic chamber 12 slightly leaks from the sliding gap between the cylinder 11 and the plunger 13. When the cam 5 releases the lifting action on the rocker arm 2, the return spring 22 extends the plunger 13 and brings the roller sliding contact surface of the rocker arm 2 into contact with the cam 5. When the pressure in the hydraulic chamber 12 is reduced due to the extension operation of the plunger 13 by the return spring 22, the check valve 20 is opened, so that the oil in the oil reservoir 14 is supplied to the hydraulic chamber 12 through the valve hole 15, and the hydraulic chamber 12 The above mentioned leakage of oil from 12 is replenished. In this way, the valve head gap, that is, the gap at the connection from the cam 5 to the valve 4 is eliminated.

Next, when the lash adjuster 10 is installed by being inclined by the angle α, when the engine is stopped for a long time,
Air is sucked from the air vent hole 13D provided at the working end, and the oil in the outer chamber 14A in the plunger 13 is supplied from the oil supply hole 17 to the oil supply passage 18.
, Or gradually leaks into the sliding gap between the plunger 13 and the cylinder 11 and gradually empties the outer chamber 14A, but the inner chamber 14B is weighed by a movable head plunger 24 above the cylindrical partition wall 23. The opening 14C is closed by the surface tension of the oil, and the outer chamber 1 of the oil is closed.
The outflow to 4A is prevented, and it can continue to be stored in the inner chamber 14B.

When the engine is restarted, a sufficient amount of oil is held in the inner chamber 14B, so that even if the plunger 13 which was in the most compressed state at the time of stop is extended by the return spring 22, the hydraulic chamber
No air is sucked into the 12. Refueling passage during engine operation
Head plunger 24 is plunged by hydraulic pressure from 18.
The inner chamber 14B and the outer chamber 14A communicate with each other while being in contact with the inner side surface 13B of the working end 13A of the thirteen, and oil is supplied to the inner chamber 14B. further,
When the head plunger 24 is pressed against the inner side surface 13B, the flow rate of the oil passing through the oil reservoir 14 is controlled by the radial groove 13C, then discharged from the air vent hole 13D, and the working end 13A of the plunger 13 and the rocker The engagement surface with the arm 2 is lubricated.

Note that a cushioning member such as rubber is disposed between the head plunger 24 and the partition wall 23, or the head plunger 24 itself is made of resin, so that the partition wall 23 of the head plunger 24 is formed.
It is also possible to prevent the occurrence of a tapping sound or an unusual sound occurring between them. In addition, if an annular washer is arranged on the partition wall 23, the outflow of oil to the outer chamber 14A as described above can be further suppressed.

[Effects of the Invention] As is apparent from the above description, according to the present invention, the partition that partitions the oil reservoir into an inner chamber connected to the valve hole and an outer chamber surrounding the inner chamber and connected to the oil supply passage. When the engine is stopped, the plunger is provided with an opening / closing member that separates both chambers and communicates during operation.Thus, even if the hydraulic lash adjuster is left in an inclined state for a long time, the partition and the opening / closing member A sufficient amount of oil can be secured in the oil reservoir, and a small hydraulic lash adjuster that does not suck air into the hydraulic chamber when the engine is restarted and does not impair the function of the hydraulic lash adjuster can be obtained. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view of a head plunger, FIG. 3 is an enlarged sectional view showing the vicinity of a working end of the plunger during operation of the engine, and arrows indicate oil. The flow of is shown. 10 ... Hydraulic lash adjuster, 11 ... Cylinder, 12 ...
... hydraulic chamber, 13 ... plunger, 14 ... oil chamber, 14A ...
Outer chamber, 14B ... Inner chamber, 15 ... Valve, 23 ... Partition wall, 24
... Head plunger (opening / closing member).

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Microfilm (JP, U) photographing the contents of the specification and drawings attached to the application for Japanese Utility Model Application No. Sho 61-66240 (Japanese Utility Model Application No. Sho 62-179306)

Claims (1)

(57) [Scope of request for utility model registration] A cylinder having a bottom and a plunger which slides on an inner peripheral surface of the cylinder to define a hydraulic chamber at a bottom thereof and has an upper end open to the atmosphere as an operating end. An oil reservoir communicating with the oil supply passage, and a valve hole communicating the oil reservoir with the hydraulic chamber are provided, and the hydraulic chamber urges a check valve for opening and closing the valve hole and a plunger in the extension direction. A partition that houses a return spring and partitions the oil reservoir into an inner chamber connected to the valve hole and an outer chamber surrounding the inner chamber and connected to the oil supply path is provided. In the hydraulic lash adjuster for a series or V-type internal combustion engine in which the inner chamber and the outer chamber communicate with each other by the opening, when the engine is stopped, the opening of the inner chamber and the outer chamber is separated. Open the opening when the engine is operating. Serial series or V-type internal combustion engine hydraulic lash adjuster for, characterized in that the closing member for providing communication between inner chamber and the outer chamber provided in the partition wall.