JPH0350306A - Hydraulic rush adjuster in valve system - Google Patents

Abstract

PURPOSE:To prevent hydraulic oil from leaking from between divided contact surfaces by sealing the divided contact part of a plunger which is fitted in the cylindrical body with a bottom so that it may slide freely and is divided into two pieces in an axial direction with a sealing material or a labyrinth structure. CONSTITUTION:An end pivot type hydraulic rush adjuster X is provided with a body 1 where the approximately whole part is embedded in an internal combustion engine body Y, and to its inside, a plunger 2 is fitted so that it may slide freely. A high pressure chamber 3 between the body 1 and a plunger 2 and a reservoir 3 for oil storage in the plunger 2 are arranged in series through a check valve 6a. In the plunger 2 which is divided into two in a horizontal direction near the oil hole 2a of a reservoir 4, an O-ring 100 is held as a seal material between the divided contact surfaces of the lunger 2. It is thus possible to prevent hydraulic oil from leaking from the reservoir 4 to the part between the inner periphery of the body 1 and the outer periphery of the plunger 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a hydraulic lash adjuster provided in a valve train of an internal combustion engine.

[Conventional technology]

The valve train in an internal combustion engine is generally susceptible to wear and thermal expansion, and the valve gap changes during operation, which adversely affects output and noise. For this reason, hydraulic lash adjusters have come into use that automatically correct this gap using the repulsive force of an elastic body and hydraulic pressure.

FIG. 12 shows a plunger equipped with a reservoir for oil sump,
Furthermore, for manufacturing reasons, the plunger is divided into two parts at a certain position of the reservoir, and the divided parts are in contact with each other to form an integral body, which is an example of a hydraulic lash adjuster. The configuration shown in the figure has a bottom (1
a) A high pressure chamber is provided between a body (1) consisting of a cylindrical frame having an open end (1b) on the opposing surface side and the bottom (1a) which is slidably fitted into the body (1). (3) and is provided with a reservoir (4) therein that communicates with the high pressure chamber (3) through an oil hole (2a); an elastic body (5) that urges the plunger (2) in the direction of protrusion of the body opening end (1b); and a check valve (5) that is also provided in the high pressure chamber (3) and controls the opening and closing of the oil hole (2a). 6a), a valve cage (6c) that holds the check valve (6a) via a valve elastic body (6b), and a valve cage (6c) that is bored in the side walls of the body (1) and the plunger (2), and that is connected to an internal combustion engine (not shown). It has oil supply holes (7a) (7b) for supplying oil sent from the side into the reservoir (4). Further, as mentioned above, the plunger (2) is horizontally divided into two parts at a position near the oil hole (2a), and the upper component part A and the lower component part B are in contact with each other at the dividing surface and are integral. is used as. Note that (4a) in the figure is an air vent hole for releasing the air contained in the oil in the reservoir (4) when it is separated, but in the example of this figure, the above-mentioned hydraulic lash adjuster is used as the end pivot of the rocker arm (8), and the hydraulic oil in the reservoir (4) is used to lubricate the part of the spherical seat (8a) where the head of the plunger (2) and the end of the rocker arm (8) come into contact. It is supplied as.

On the other hand, hydraulic oil sent from the internal combustion engine side is supplied into the reservoir (4) through the oil supply holes (7a) and (7b), and is appropriately fed into the high pressure chamber (3) through the oil hole (2a). It will be filled with.

This type of hydraulic lash adjuster uses the rigidity of the hydraulic oil that occurs when pressure is applied to the hydraulic oil filled in the high pressure chamber (3), and the elastic body that is also inserted into the high pressure chamber (3) when the pressure is released. It expands and contracts by utilizing the repulsive force of (5) that tends to expand, and performs a correction operation so that the gap in the valve mechanism caused by thermal deformation or the like is reduced to zero.

[Problem that the invention seeks to solve]

However, when such a split plunger (2) is used, the reservoir (4) is inserted through the gap between the split contact parts.
) leaks, and furthermore, the hydraulic oil leaks out from the oil supply hole (7a) on the body (1) side through between the outer circumferential surface of the plunger (2) and the inner circumferential surface of the body (1), or as shown in Fig. 13. If the entire lash adjuster is tilted, the body opening end (
It also leaks to the outside from the 1b) side. The former of these leakage modes occurs when the divided contact position of the plunger (2) is at a position lower than the oil level in the case of the amount of oil that should normally be secured in the reservoir (4), or when the body (1) The oil supply hole (
The closer the position 7a) is to the body bottom (1a), the more noticeable it becomes. On the other hand, if the entire hydraulic lash adjuster is tilted as shown in FIG. 13, the greater the tilt, the more severe the leakage will be.

Therefore, the oil level H in the reservoir (4) decreases, and when oil is sucked in from the reservoir (4) due to restart, etc., the air above the oil level H is simultaneously sucked into the high pressure chamber (3). It will end up being put away.

In particular, when the internal combustion engine is stopped while the cam (9) is in contact with the rocker arm (8) with its cam nose (9a), this hydraulic lash adjuster is compressed and becomes the most shortened state (bottomed state). When the engine is restarted from this state, the sliding stroke between the plunger (2) and the body (1) becomes maximum, and the amount of oil sucked into the high pressure chamber (3) becomes maximum. However, when the engine is stopped, oil is not supplied from the internal combustion engine side, so the reservoir (4
) It is almost impossible to secure the amount of oil in the high pressure chamber (3), and the air suction into the high pressure chamber (3) becomes the most severe when the engine is restarted.

When air is sucked into the high pressure chamber (3), the plunger (
When 2) is pressed, the rigidity of the hydraulic oil that should be generated in the high pressure chamber (3) is extremely reduced (becomes spongy), making it impossible to correct the valve gap appropriately.

The present invention was devised in view of the above-mentioned problems of the prior art, and provides a structure that can prevent oil from leaking from the gap between the split contact portions of the split plunger of the hydraulic lash adjuster having the above structure, This is an attempt to solve the above problem.

[Means for solving problems]

Therefore, the basic feature of the present invention is to provide a sealing material in the divided contact portion of the divided plunger and/or to form the divided contact portion into a labyrinth structure to seal the gap therebetween.

As such a sealing material, various materials such as rubber, paper, plastic, metal, paste sealant, engineering plastic, and grease can be used.

[For production]

Even if the hydraulic lash adjuster becomes vertical, nearly vertical, or tilted due to its mounting condition or posture when the engine is stopped, the sealing material and/or labyrinth structure The gap seal prevents leakage of hydraulic oil from inside the reservoir, so a necessary and sufficient amount of oil is secured in the reservoir, and air is prevented from being sucked into the high pressure chamber.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the accompanying drawings.

FIG. 1(a) shows an embodiment of the present invention.

In the figure, X is the end pivot type hydraulic lash adjuster according to the present invention, (1) is the body of the lash adjuster X, (2) is the plunger of the lash adjuster X, and (3) is the body (1) and the plunger. (2) is a high pressure chamber formed between the two, (4) is an oil reservoir provided in the plunger (2), and (2a) is an oil hole that communicates the high pressure chamber (3) with the reservoir (4). , (7a) and (7b) are oil supply holes that supply hydraulic oil sent from the internal combustion engine side into the reservoir (4).

In this embodiment, the rocker arm (10) can open the valve (10), which was previously closed by the repulsive force of the valve spring (10a), by intermittently pressing it with the rotation of the cam (9).
The above hydraulic lash adjuster
) The entire structure is buried from the side.

And the plunger of this hydraulic lash adjuster
2) is used which is horizontally divided into two parts near the oil hole (2a) of the reservoir (4), and these two parts come into contact at the dividing surface and form an integral body. It is used. In this embodiment, an O-ring (100) is sandwiched between the divided contact surfaces as a sealing material, and the O-ring (100) is inserted between the reservoir (4), the inner peripheral surface of the body (1), and the plunger (2).
) Prevents leakage of hydraulic oil between the outer circumferential surfaces.

Therefore, the cam (9) is on the base circle and the rocker arm (8)
Regardless of the state in which the cam nose (9a) is in contact with the rocker arm (8) (when the hydraulic lash adjuster X is in the bottomed state),
Even when the engine is stopped, with no hydraulic oil being supplied from the internal combustion engine side, and even when the entire hydraulic lash adjuster X is tilted as shown in Fig. 1(b), Because the above sealing effect is obtained, even if the internal combustion engine stops with the hydraulic lash adjuster This prevents oil from leaking between the contact surfaces of the reservoir (4) and ensures a sufficient amount of oil in the reservoir (4).

Therefore, air is not sucked into the high pressure chamber (3) at the time of restart.

2 to 5 show other embodiments in which O-rings (101) to (104) similar to those in the previous embodiment are used as sealing materials, and these embodiments are used to separate the plunger (2). Contact surface shape and O-rings (101) to (104)
The installation methods shown here are different from those of the previous embodiment. In each case, these O-rings (101) to (104) are interposed between the divided contact surfaces of the plunger (2) to form a seal therebetween. Particularly in FIGS. 4 and 5, a labyrinth structure is formed between the divided contact surfaces to further enhance the sealing effect.

6 to 9 show an annular rubber plate (
105) to (108), these rubber plates (
105) to (108) are shown.

FIG. 10 shows another embodiment of the present invention, in which a ring-shaped sealing material (109) surrounds the sides between the divided contact surfaces of the plunger (2). That is, the inner circumferential protrusion (109a) of the sealing material (109) is embedded in the outer circumferential surface of the upper component A of the plunger (2), and the inner circumferential surface of the sealing material (109) extending vertically from there is embedded in the outer circumferential surface of the upper component A of the plunger (2). The plunger (
2) forms a seal between the divided contact surfaces.

11(a) to (f) show labyrinth structures (110a) to (110a) to (110a) to (110a) to (110a) to
0f) is shown.

〔Effect of the invention〕

As detailed above, according to the present invention, the contact surfaces of the split type plunger are sealed using the sealing material and/or the labyrinth structure, so even if the hydraulic lash adjuster becomes bottomed and the engine Even when the engine is stopped, leakage of hydraulic oil from between the divided contact surfaces is prevented, and a sufficient amount of oil is ensured in the reservoir.

Therefore, air is not sucked into the high pressure chamber when restarting.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are cross-sectional views showing one embodiment in which the hydraulic lash adjuster of the present invention is used in an end-pivot type valve mechanism, and FIG. 2 is a plunger split contact portion showing another embodiment. FIG. 3 is an enlarged sectional view of the plunger split contact part showing another embodiment, FIG. 4 is an enlarged sectional view of the plunger split contact part showing another embodiment, and FIG. 5 is the same. 6 is an enlarged sectional view of a plunger split contact portion showing another embodiment; FIG. 7 is an enlarged sectional view of a plunger split contact portion showing another embodiment; FIG. 7 is an 11-plunger split showing another embodiment. FIG. 8 is an enlarged sectional view of the plunger split contact part showing another embodiment; FIG. 9 is an enlarged sectional view of the plunger split contact part showing another embodiment; FIG. 10 FIG. 11(a) is an enlarged sectional view of a plunger split contact portion showing still another embodiment.
(b) Cc,') (d) (e) (f) is an enlarged sectional view of the plunger split contact portion showing another embodiment, the 12th
The figure is a sectional view showing an example of the structure of a conventional hydraulic lash adjuster used in an end-pivot type valve mechanism.
FIG. 3 is an explanatory diagram showing a state in which oil leaks from the body opening end when such a conventional hydraulic lash adjuster is tilted. In the figure, (1) is the body, (2) is the plunger, (2a)
is the oil hole, (3) is the high pressure chamber, (4) is the reservoir, (7a)
(7b) is the oil supply hole, (8) is the rocker arm, (9) is the cam, (10) is the valve, (100) (101) (10
2) (103) (104) (105) (106)
(107), (108), and (109) indicate sealing materials. 12- Unexamined Japanese Patent Publication No. 3 50306 (7) Figure 3 0

Claims (1)

[Claims] A high-pressure chamber is formed between a body consisting of a cylindrical frame having an open end on the side facing the bottom and the bottom that is slidably fitted into the body, and a high-pressure chamber is connected to the high-pressure chamber through an oil hole. A plunger is provided inside the high pressure chamber and the plunger is inserted into the high pressure chamber and the plunger is inserted into the high pressure chamber and the plunger is inserted into the high pressure chamber. a check valve that is also provided in the high pressure chamber and controls opening and closing of the oil hole; a valve cage that holds the check valve via the valve elastic body; , in a hydraulic lash adjuster for a valve mechanism having an oil supply hole for supplying oil sent from an internal combustion engine side into the reservoir, a sealing material is provided at a divided contact portion of the plunger, and/or a sealing material is provided in the divided contact portion. A hydraulic lash adjuster for a valve train, which has a labyrinth structure and seals the gap between the parts.