JPS6067706A - Closed type oil pressure rush adjuster - Google Patents

Abstract

PURPOSE:To improve the sealing performance and durability by fitting in an adjuster body the lower and upper plungers on the same axis and by interposing a diaphragm between both plungers and forming an oil reservoir chamber between this diaphragm and the lower plunger. CONSTITUTION:This rush adjuster 1B, which is used in the moving valve mechanism of an internal combustion engine, has a lower plunger 27 which is fitted, in a free slide state, in a cylindrical and bottomed adjuster body 25 and which forms a high pressure chamber 26 between the body 25 bottom and itself. Also it has an upper plunger 29 which slides within the body 25 together with this plunger 27 and which forms a hollow chamber 28 between the lower plunger 27 and itself. And a diaphragm 31 is provided in the hollow chamber 28, and a reservoir chamber 30 is formed between this diaphragm and the lower plunger 27. This reservoir chamber is connected through to the high pressure chamber 26 via a through pass 32 and a non-return valve 18, and the diaphragm 31 is fixed with an inside ring-shaped body 42 fitted, in a free slide state, in an annular concave section 41 between the both plungers 27 and 29.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lash adjuster used in a valve mechanism of a four-stroke engine, and more particularly to a closed-type hydraulic lash adjuster (hereinafter abbreviated as lash adjuster) that utilizes hydraulic pressure.

The lash adjuster uses the elastic force of the elastic member and hydraulic pressure to achieve zero lash operation of the valve train, thereby achieving quiet operation and a maintenance fleet. It is being used in

FIGS. 1 and 2 show a conventional example of the lash adjuster, which consists of a bushing rod 4 that operates a rocker arm 3 that opens and closes a valve 2 of a four-cycle engine, and a valve drive cam 5. It is installed between the valve train and the valve train to operate the valve train with zero lash.

That is, in the lash adjuster 1, a plunger 8 which forms a high pressure chamber 7 between the body 6 and the body 6 is slidably inserted into a bottomed picture-shaped body 6 shown in FIG. is urged upward by the resilient member 9, and the stop ring 10 fitted into the upper end of the body 6
This prevents Pushinger 8 from falling upward.

The plunger 8 is composed of a bottomed main body 11 and a cover 12 that covers the upper part of the main body 11, and the cover 12 is formed with a recess into which the lower end of the bushing rod 4 is engaged. ing. Further, a diaphragm 14 that forms a reservoir chamber 13 between the main body 11 and the main body 11 is fixed, and a diaphragm 14 is provided at the lower end of the reservoir chamber 13 to communicate the reservoir chamber 13 and the pressure chamber 7. A communication path 15 is provided to allow the Further, the communication passage 15 is provided with a check valve 16 that prevents oil from flowing from the high pressure chamber 7 into the reservoir fi13. It has a structure in which it is urged toward the communication path 15 by an elastic material 19.

Hiko, what is indicated by the symbol 'JPF20' in Figure 2 is a seal ring, and this seal ring 20 is installed between the body 6 and pusher 8 to prevent oil from leaking in the reservoir chamber 13. The lash adjuster 1 configured as shown in FIG. This gap is absorbed by rising.゛Also, since oil in the reservoir chamber 13 flows into the pressure chamber 7 via the check valve 16 due to the rise of the pusher 8, a rigid body is formed between the valve drive cam 5 and the bushing rod 4, and the valve drive cam 5 is transmitted to the bushing rod 4. Note that some of the oil in the high pressure chamber 7 leaks from between the plunger 8 and the body 6 when the force of the valve operating cam 5 is transmitted to the bushing rod 4 and flows through the oil inlet 21. It is designed to be returned to the reservoir chamber 13.

However, with such a lash adjuster,
A diaphragm 14 is used as a part that performs an oil sealing action.
It is essential to use the seal ring 20 and the seal ring 20, and from the viewpoint of preventing oil leakage, it has been desired to reduce the number of locations requiring seals.

Therefore, in another conventional example shown in FIG. 3, two plungers 22A are provided in the body 6A of the lash adjuster IA.
, 22B are slidably inserted, respectively, so that a reservoir chamber 13A is formed between the upper plunger 22A and the diaphragm 23 fixed to the body 6, and the lower plunger 22B.

That is, like the lash adjuster 1 of the prior art example, this lash adjuster 1m increases the lash in the valve system by raising the plungers 22A, 22B and the cover 12m together with the resilient member 9. The plungers 22A, 22B
When the oil rises, the oil in the reservoir chamber 43 is allowed to flow into the high pressure chamber 7A through the communication groove 24 on the upper surface of the plunger 22B and the communication path 13A, thereby creating a rigid body between the bushing rod 4 and the valve operating cam 5. Thus, the assist force of the valve operating cam 5 is transmitted to the bushing rod 4.

This other conventional lash adjuster IA is
Since the only sealing component is the diaphragm 23, this is superior to the conventional two-shuttle adjuster 1 in terms of preventing oil leakage.

However, since this lash adjuster LA has a structure in which the upper and lower plungers 22A and 22B can move separately, the upper and lower plungers 22A and 22B may become separated from each other due to, for example, a valve jump. Plungers 22A, 2 separated from each other
If 2B approaches again and collides with each other, there is a risk that they will hit the diaphragm 23 strongly and cause a shock. Also,
Even when the upper and lower plungers 22A and 22B move together without separating from each other, the diaphragm 23 moves up and down together with these plungers 22A and 22B, so it is difficult to move when the engine rotates at high speed. However, if the diaphragm 23 is moved intermittently, a problem arises in terms of durability.

This invention was proposed by the present inventor in view of the above-mentioned circumstances, and it solves the problems of conventional lash adjusters, and is an inexpensive closing type hydraulic lash that has a small number of parts and has excellent durability during high-speed engine rotation. The purpose is to provide an adjuster.

The present invention will be described below based on an embodiment shown in FIGS. 4 and 5. In the figure, parts common to those in the conventional example are given the same reference numerals to simplify the explanation.

The lash adjuster IB of the present invention includes a bottomed adjuster body 25, a lower pump sinker 27 that is slidably fitted into the adjuster body 25 and forms a high pressure chamber 26 between the adjuster body 25 and the bottom of the adjuster body 25. An upper plunger 29 slides in the adjuster body 25 together with the lower plunger 27 and forms a hollow part 28 between it and the lower plunger 27, and a reservoir chamber is provided in the hollow part 28 and between the lower plunger 27. The basic structure includes a diaphragm 31 forming a diaphragm 3o.

The lower plunger 27 is provided with a communication passage 32 that communicates the high pressure chamber 26 with the reservoir chamber 30 , and a lower part of the communication passage 32 is provided with a passageway 32 that connects the high pressure chamber 30 to the high pressure chamber 26 . A check valve 16A that only allows flow is provided. Further, an annular protrusion 33 is provided on the upper surface of the lower plunger 27, and the inner circumference of the protrusion 33 is
It serves as a sealing surface between the diaphragm 31 and the diaphragm 31.

Further, the shaft portion 34 at the lower end of the upper plunger 29 is fitted into the inside of the protrusion 33, and both plungers 27.
A fitting hole 35 is formed to solidify the parts 29 together.

The upper plunger 29 has a cross-sectional shape as shown in FIG. 4, and its upper end is formed into a spherical shape to receive the fulcrum of the U-shaped arm. Also,
The upper plunger 29 is provided with a flange portion 36 that slidably fits into the adjuster body 25, and the space between the flange portion 36 and the lower plunger 27 serves as the aforementioned hollow portion 28. There is. Furthermore, in the collar portion 36,
A communication hole 37 is formed to communicate the hollow portion 28 with the outside air. The upper plunger 29 also holds a retainer 38 fixed to the upper end of the adjuster body 25 on the collar portion 3.
By still contacting the adjuster body 6, falling off from the adjuster body 25 is prevented.

The diaphragm 31 is made of an elastic material such as rubber, and as shown in FIG. An inner annular portion 42 that is slidably and tightly fitted into an annular recess 41 between the protrusion 34 of the upper plunger 27 and the lower end of the upper plunger 29; # film portion 43.

The outer annular portion 40 includes a
A metal ring 44 is interposed to provide rigidity. Further, the inner annular portion 42 is formed with a gourd-shaped cross section as shown in FIG.
It is inserted into the annular recess 4 with a slight margin.
1 and a stepped portion 45 on the outer periphery of the upper plunger 29 over a stroke S.

The inner annular portion 42 has inner and outer protrusions 46 and 47 in contact with the outer circumference of the upper plunger 29 and the inner circumference of the protrusion 33, respectively, similar to a commonly used X-shaped oil seal. This prevents oil leakage from the reservoir chamber 30. In addition, in this example,
Although the inner and outer peripheries of the inner III annular portion 42 are used as sealing surfaces, a method may be adopted in which either one of the inner or outer peripheries is used as a sealing surface.

In the lash adjuster IB configured in this way, the lower plunger 27 and the upper plunger 29 are urged by the resilient member 9 and rise together, thereby pressing a rocker arm (not shown) against the tip of the upper plunger 29. This prevents the occurrence of rash in the valve train.

Then, when the plungers 27 and 29 rise, the oil in the reservoir chamber 30 flows into the high pressure chamber 26 through the communication passage 32, thereby causing the adjuster body 25 and the upper plunger 29 to become rigid bodies in the valve train. Thus, the power of the valve operating cam (not shown) is transmitted to the rocker arm.

Also, since the inner annular portion 42 of the diaphragm 31 can move relative to the plunger 2.7.29 over the stroke S along the axial direction, the thin film of the diaphragm 31 as the plunger 27.29 moves Deformation growth of the portion 43 can be reduced. Furthermore, due to the damping effect due to the frictional resistance caused by the movement of the inner annular portion 42, the amplitude of the stress generated in the thin Ila$43 when the plunger 27.29 moves up and down violently is reduced, thereby improving its durability. can be improved.

In the above-mentioned embodiment, the upper plunger is tightly fitted into the lower lunge and they are fixed together, but it is of course possible to use screws or other fixing means. In addition, in the above embodiment, the tip of the upper plunger is made spherical in order to allow the upper plunger to directly operate the rocker arm. For example, it may be provided in the upper plunger, which is a concave portion that engages with the bushing rod.

As is clear from the above description, the present invention includes a lower plunger that is slidably fitted into an adjuster body and forms a high pressure chamber between the lower plunger and the lower plunger that is integrally bracketed with the core lower plunger. An upper plunger forming a space between the two is slidably inserted,
A diaphragm forming a reservoir chamber between the lower plunger and the cocoon space is provided, and the diaphragm is movable in a sliding direction with respect to both plungers, and is in close contact with at least one of the plungers. It is characterized by the fact that the number of parts required is only one on the diaphragm, and the necessary tightness can be secured with a small number of parts, and it is also possible to secure the required tightness for the upper and lower plungers. By freely moving the diaphragm, it is possible to prevent damage to the diaphragm caused by sudden vertical movement of the plunger.

[Brief explanation of drawings]

Figures 1 and 2 show a conventional example of a lash adjuster. Figure 1 is a side view of the entire valve train, Figure 2 is a longitudinal cross-sectional view of the lash adjuster, and Figure 3 is a lash adjuster and other parts. 4 and 5 show an embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of the conventional example, and FIG.
The figure is a side view of the left hand section of the diaphragm. 16A・Curve stop valve, 25・Curve adjuster body, 26・
... Hyperbaric chamber, 27, curved lower chamber, 28...
・Hollow part, 29・Curved upper plunger, 3°...
...Sf-/(chamber, 31...-diaphragm, 32
...Communication path, 33. Curved missing portion, 34..Shaft portion, 35..Fitting hole, 4o...Outer Il! 1I
IA-shaped part, 41... annular recessed part, 42 - curved inner annular part, 43... thin film part. Medical Drop - Mai Ward V) Castle

Claims (1)

[Claims] An adjuster body made of a straw-like body with a closed paper part and an open end, and a lower part that is slidably fitted into the adjuster body and forms a high pressure chamber between the paper part of the adjuster body. a plunger, an upper plunger that is fitted into the adjuster body together with the lower plunger and slides together and forms a space between the lower plunger; and an oil reservoir between the lower plunger and the lower plunger in the space. A diaphragm forming a chamber, a communication passage bored in the lower plunger to communicate the oil reservoir chamber and the high pressure chamber, and a communication passage provided in a part of the communication passage for communicating hydraulic oil from the oil reservoir chamber to the high pressure chamber. The diaphragm is slidably received in at least one of the lower plunger and the upper plunger, and the outer sacrum ring portion tightly fixed to the inner wall of the adjuster body. A closed hydraulic lash adjuster, comprising an inner annular portion that contacts a can.