JPH0331504A - Hydraulic type valve rush adjustor - Google Patents

Abstract

PURPOSE:To reduce the thickness of each peripheral wall of a body and a cylinder by forming each projection part on the peripheral walls of the body and cylinder and installing a shielding member in liquidtight form between the projection parts of the both parts and forming an oil holding chamber. CONSTITUTION:A hydraulic valve rush adjustor is equipped with a cylindrical body 3 which is fitted in slidable manners in a bore formed on a cylinder head and whose upper edge is closed, and a cylinder 7 is integrally installed coaxially with the body 3 onto the inner surface of the upper edge wall 2. In the cylinder 7, a plunger 11 is fitted, and a high pressure chamber 15 is formed in the upper part. In this case, the first and second projection parts 4 and 8 are formed inside the peripheral wall of the body 3 and the outside of the peripheral wall of the cylinder 7, and an annular shielding member 6 is installed in liquidtight form between the projection parts 4 and 8, and an oil holding chamber 10 is formed, and the oil holding chamber 10 is allowed to communicate to the high pressure chamber 15 through an oil feeding hole 17, plunger oil passage 18, and a check valve 12.

Description

[Detailed Description of the Invention] I. Natsume Kamidan and Satokuni Atsushi The present invention relates to a hydraulic nosure adjuster for a direct-acting valve train, and more specifically, to a hydraulic nosure adjuster for a direct-acting valve system, and more specifically, to a lightweight oil-holding space adjuster. Concerning large hydraulic valve lash adjusters.

Conventional technologyHydraulic valve brake adjuster for direct-acting valve train (
The HLA (hereinafter abbreviated as HLA) reciprocates following the movement of the cam. The lighter the HLA, the better its followability (to achieve higher engine speeds, it is necessary to reduce the weight of the HLA.

In an HLA for a direct-acting valve train, the cam directly contacts the crown surface of the body, so the body has a relatively large diameter. Therefore,
The body of the HLA tends to be thicker (and heavier) than the lash control portion, which is the center of the ILA.

In order to reduce the weight of the HLA, a well-known method is to form a space between the body peripheral wall and the cylinder and use the formed space as an oil holding space.

FIG. 3 schematically shows the configuration of a conventional hydraulic valve lash adjuster for a direct-acting valve train. The illustrated valve lash adjuster includes a cylindrical body 3 whose upper end is closed. The body 3 is attached to the blocking wall 2 of the body 3.
A cylindrical cylinder 7 is provided coaxially with the cylinder. By the peripheral wall of the body 3, the peripheral wall of the cylinder 7, and the shielding member 6,
An oil holding chamber IO is formed.

The inner wall of the oil holding chamber of the illustrated HLA body is first processed and formed by a non-cutting method such as cold forging. Next, a stepped portion as shown in the figure is formed by cutting. By the "crimping method", a shielding member is brought into contact with the formed step, and a part of the peripheral wall of the body and a part of the peripheral wall of the cylinder below the abutting shielding member are plastically deformed by means such as a punch. The shielding member is attached to the stepped portion in a liquid-tight manner.

The step not only serves for the axial positioning of the shielding member, but also as a means of supporting the axial forces applied when the shielding member is fluid-tightly attached to the step by means of the "crimping method". For this reason, the abutment area of the shielding portion needs to be large enough to support the above-mentioned axial force.

That is, among the member dimensions in the figure, ds da and D4
D- becomes large, and as a result, the peripheral wall of the body and the peripheral wall of the cylinder become thick.

As described above, in the conventional HLA for a direct-acting valve train, the peripheral wall of the body and the peripheral wall of the cylinder have a thick structure.

Therefore, it is not possible to reduce the weight of the body, which accounts for most of the weight of the HLA, and therefore it is not possible to ensure the desired followability, and there is a problem that it is not easy to achieve high engine speed. there were.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hydraulic valve lash adjuster for a direct-acting valve train that is lightweight and has a large oil storage space.

According to the present invention to solve the problems, there is provided a cylindrical body whose upper end is closed and whose upper end surface directly contacts the cam, a cylinder coaxially attached to the upper end wall of the body, and a cylinder that slides into the cylinder. a plunger that is freely fitted and whose lower end surface comes into contact with the shaft end surface of the engine valve; an oil holding chamber is formed between the inner periphery of the body and the outer periphery of the cylinder;
In the hydraulic valve lash adjuster for a direct-acting valve train, in which a high pressure chamber is formed in the plunger, a first protrusion that protrudes inward in the circumferential direction is formed on the peripheral wall of the body; A second protrusion projecting outward in the circumferential direction is formed on the peripheral wall of the cylinder, and a shielding member is fluid-tightly attached between the first protrusion and the second protrusion. To provide a hydraulic valve lash adjuster featuring:

Mistake 1 Hereinafter, embodiments of the hydraulic valve lash adjuster according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a lash adjuster according to the present invention.

The illustrated valve lash adjuster includes a cylindrical body 3 whose upper end is closed. The body 3 is slidably attached to a bore (not shown) provided in the cylinder head. A cylindrical cylinder 7 is provided on the closed wall of the body 3, that is, the upper end wall 2, coaxially with the body 3. A cam (not shown) is in direct contact with the upper surface of the upper end wall 2, that is, the crown surface. A first protrusion 4 that protrudes inward in the circumferential direction is formed on the inner side of the circumferential wall of the body 3, and a second protrusion 8 that protrudes outward in the circumferential direction is formed on the outer side of the circumferential wall of the cylinder 7. There is.

A shielding member 6 made of an annular flat plate is fluid-tightly attached between the first protrusion 4 and the second protrusion 8. The peripheral wall of the body 3, the peripheral wall of the cylinder 7, and the shielding member 6 form an oil holding chamber IO.

A plunger 11 is slidably fitted into the cylinder 7, and a high pressure chamber 15 is formed between the upper end wall 2 of the body, the cylinder 7, and the plunger 11. Plunger 11
The lower end of the valve is in contact with the shaft end surface of an engine valve (not shown). A first oil supply hole 16 is provided in the peripheral wall of the body 3 and communicates with an oil gear lary (not shown) of the cylinder head, so that the oil gear lary communicates with the oil holding chamber lO. A second oil supply hole 17 is provided on the peripheral wall of the cylinder 7.
is formed. The plunger 11 has a second oil supply hole 1.
7 to the oil holding chamber lO and check valve 1.
Plunger oil passage 18 communicating with high pressure chamber 15 via 2
is formed. In this way, the oil holding chamber lO communicating with the oil gear gallery includes the second oil supply hole 17 and the plunger oil passage 18.
It also communicates with a high pressure chamber 15 via a check valve 12.

A return spring 14 is provided between the upper end surface of the plunger 11 and the upper end wall 2 of the body, which acts to bias the plunger 11 toward the axial end of the engine valve. The check valve 12 is held in place by a spring (not shown) provided between the check valve 12 and the retainer 13.

The hydraulic valve lash adjuster configured as described above operates as follows.

As the cam moves, a downward force is applied to the body 3. This downward pressing force is transmitted from the body 3 to the plunger 11 via the high pressure chamber 15 and pushes the engine valve 3 open. During this time, the plunger 11 is attached to a valve spring (not shown).
As a result of this action, high pressure is generated within the high pressure chamber 15, so that a portion of the oil within the high pressure chamber 15 flows out from the gap between the outer circumferential surface of the plunger 11 and the inner circumferential surface of the cylinder 7. The plunger 11 is pushed upward by the amount of oil that flows out.

When the valve is closed and seated, the plunger 11 is released from the action of the valve spring, and a slight clearance is created in the valve train, but the plunger 11 is pushed downward by the action of the return spring 14, so that Clearance is compensated instantly. At this time,
Since the high pressure chamber 15 has a negative pressure with respect to the oil holding chamber 10, the oil in the oil holding chamber 10 flows into the high pressure chamber 15 via the second oil supply hole 17, the plunger oil passage 18 and the check valve 12. Oil is supplied to the oil holding chamber 10 from an oil gear gallery of the cylinder head through a first oil supply hole 16. While repeating the above cycle, the clearance of the valve train is always maintained at zero.

If the engine valve remains open when the engine is stopped, the plunger 11 will be displaced until it comes into contact with the crown surface 2, reducing the volume of the high pressure chamber 15, so a relatively large amount of oil will be required when the next engine is started. becomes. however,
Even if oil is not supplied to the HLA from the oil gear gallery in time, if the volume of the oil holding chamber 10 is large enough, the oil held in the oil holding chamber 10 can cover the oil consumption required at engine startup. . Therefore, the larger the volume of the oil holding chamber IO, the more advantageous.

Figures 2a and 2b show an example of how the shielding member may be attached. First, a means such as a punch is forcibly inserted between the peripheral wall of the body 3 and the peripheral wall of the cylinder 7.
plastically deforming the peripheral wall of the cylinder 7 and a part of the peripheral wall of the cylinder 7,
At the same time as forming the first protrusion 4 and the second protrusion 8, annular grooves 22 and 23 are formed below the first protrusion 4 and the second protrusion 8, respectively. Next, the shielding member 6 consisting of the annular flat plate portion 21 and the rim portion 20 is brought into contact with the annular flat plate portion 21 against the first protrusion 4 and the second protrusion 8 (see FIG. 2a), and the rim portion 20 An upward pressing force is applied to the end face of the shield member to plastically deform it, and the shielding member is attached in a liquid-tight manner (see Fig. 2b).

In this embodiment, the present invention has been explained by taking as an example a shielding member consisting of an annular flat plate portion and a rim portion, but the shielding member consisting only of an annular flat plate portion is brought into contact with the protrusion, and the lower body circumferential wall of the shielding member is Alternatively, it may be attached liquid-tightly by a so-called "caulking method" in which a part of the cylinder peripheral wall is plastically deformed.

1 As is clear from the above description, in the hydraulic valve lash adjuster according to the present invention, first and second protrusions are formed on the peripheral wall of the body and the peripheral wall of the cylinder, respectively, and the two protrusions Since the shielding member is fluid-tightly attached between the cylinders, the peripheral wall of the body and the peripheral wall of the cylinder can be made thin. Therefore, it is possible to realize a hydraulic valve lash adjuster that is lightweight and has a large oil storage space. As a result, desired followability can be ensured, and it becomes possible to realize higher speeds of the engine.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of a hydraulic valve lash adjuster of the present invention, FIGS. 2a and 2b are diagrams showing an example of a method for installing a shielding member, and FIG. FIG. 2 is a diagram showing the configuration of a conventional hydraulic valve lash adjuster. 3. Body, 7. Cylinder, 11φ. Plunger, 15. High pressure chamber Fig. 20, Fig. 2b η

Claims (1)

[Claims] (1) A cylindrical body whose upper end is closed and whose upper end surface directly contacts the cam, a cylinder coaxially attached to the upper end wall of the body, and which is slidably fitted into the cylinder and whose lower end surface is connected to the engine. a plunger that comes into contact with the shaft end surface of the valve, an oil holding chamber is formed between the inner periphery of the body and the outer periphery of the cylinder, and a high pressure chamber is formed within the plunger; In a hydraulic valve lash adjuster for a direct-acting valve system, a first protrusion protruding inward in the circumferential direction is formed on the circumferential wall of the body, and a first protrusion protruding outward in the circumferential direction is formed on the circumferential wall of the cylinder. A hydraulic valve lash adjuster characterized in that a second protrusion is formed, and a shielding member is fluid-tightly attached between the first protrusion and the second protrusion.