JPH0625607Y2 - Direct acting hydraulic lash adjuster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a hydraulic thruster for automatically correcting a valve gap in a valve train of an internal combustion engine by hydraulic force and elastic force of an elastic member. The present invention relates to an improvement in a direct-acting hydraulic lash thruster used for a direct-acting valve operating mechanism that is pressed.

2. Description of the Related Art It is extremely important to reduce the weight of a hydraulic ratchet thruster in order to maintain good dynamic characteristics of the valve mechanism, including its incorporation in an overhead cam type internal combustion engine. In addition, the volume of the high-pressure chamber and the oil sump chamber that store oil together with their respective components are devised so as to have the minimum necessary dimensions.

By the way, when the engine is stopped, oil leaks out of the high pressure chamber of the lash-adjuster, so when the engine is restarted, the amount of oil is insufficient and a large amount of air is sucked in. There is a problem of not getting.

FIG. 2 shows a conventional example of a hydraulic ratchet thruster in a direct-acting valve operating mechanism, in which a bucket (11) has a top plate portion (11a) at an upper portion and an opening portion (11b) at a lower portion. A sleeve (12) is fixed to the opening side of the hollow cylindrical body, the sleeve has a body (13) slidably fitted in its support hole (12a), and the body has an inner periphery. A plunger (14) is fitted so as to be slidable on the surface and in contact with the lower surface of the top plate portion of the bucket (11).

The high pressure chamber (15) is formed between the inner peripheral surface of the body (13) and the plunger (14), and the elastic body (16) is formed in the high pressure chamber (1).
The plunger (1) located at 5) and adapted to urge the body (13) outward from the bucket (11).
4) is provided with an oil hole (14a) for introducing oil into the high pressure chamber (15). Also, a check valve (17) and a check valve cage (1) that control the opening and closing of the oil hole.
And 8) are provided in the high pressure chamber. The oil hole (14
A plunger oil reservoir chamber (19a) is provided in a portion defined by the plunger (14) and the lower surface of the bucket top plate adjacent to the high pressure chamber (15) through a).

In addition, the bucket (11), sleeve (12) and body (1
A bucket oil reservoir chamber (19b) is provided in a portion defined by 3) and the plunger (14), and communicates with the plunger oil reservoir chamber (19a) by a communication groove (11d). Furthermore, the bucket (11) is provided with an oil hole (11c) for introducing oil from the outside. As shown in FIG. 3, the hydraulic lash adjuster (1) is slidably fitted and positioned by the bucket (11) in the support hole (2a) of the cylinder head (2). The top plate (11a) side of the bucket contacts the cam surface 3,
The closed end side of the body is arranged so as to abut the shaft end surface of the valve (4).

Problems to be Solved by the Invention In the structure of the conventional example, when the engine is stopped, the oil in the high pressure chamber (15) leaks from the gap between the body (13) and the plunger (14) as shown in FIG. Further, when the valve is opened and stopped, the force of the valve spring (not shown) acts on the body (13), so that the body (13) moves from the position at the time of the stop and the bucket (11) moves. Contract in. Therefore, the volume in the high pressure chamber (15) is reduced, so that the oil in the high pressure chamber (15) flows from the gap between the inner periphery of the body (13) and the outer periphery of the plunger (14) into the bucket oil reservoir chamber (19b).
Leak to. When the engine is restarted from this state, the body (13) will eventually return to the position at the time of the stop, but at this time, if the amount of oil in the plunger oil sump chamber (19a) is insufficient, air will flow from the oil sump chamber (19a) to high pressure. Intake into the chamber (15). As a result, the oil in the high-pressure chamber (15) mixed with a large amount of bubbles may cause an extreme decrease in rigidity and may not be able to perform the function of normally operating the valve.

The present invention aims to avoid such a problem, and to prevent a decrease in the amount of oil in the oil reservoir (19a),
The oil leaked from the high-pressure chamber (15) is surely secured to the oil reservoir chamber (1
It is intended to provide an automatic valve gap compensating device having a novel structure having an oil recirculation path that can return to 9a) to secure a required amount of oil and always supply an appropriate amount of oil to the high pressure chamber (15). is there.

Means for Solving the Problems In order to achieve the above object, in the present invention, a high pressure chamber (1
5) An oil recirculation passage serving as a short-circuit passage for recirculating oil leaking from the inside into the gap between the body (13) and the plunger (14) to the plunger oil reservoir chamber (19a) is provided.

The simplest structure for providing the oil return passage is to provide it directly on the side wall of the plunger, but in addition to that, other cases are possible in the case shown in the embodiment.

Function As described above, the oil leaked from the high pressure chamber is not stored in the bucket oil storage chamber (19b) as in the conventional case, but in the plunger oil storage chamber (1
Since the oil can be recirculated to 9a), even if the amount of oil in the plunger oil reservoir is insufficient, the shortage can be supplemented by this amount of reflux oil. No worries, you can assure the stable function of the Rust Exchange. In particular, when the slit-shaped oil return passage is used as in the embodiment of the present invention, a wide oil return passage can be secured against a slight movement of the plunger, and the structure is simple and processing is easy.

Embodiment FIG. 1 shows an embodiment of the present invention, in which a bucket (1
1) the top plate (11a) is on the upper side and the opening (11a) is on the lower side.
b) with a bottomed hollow cylinder, the sleeve (12) is fixed to the opening side, and the sleeve has a support hole (12).
A body (13) is slidably fitted in a), and a plunger (14) is slidably fitted on the inner peripheral surface of the body. A ring-shaped member (20) is provided between the upper end of the plunger (14) and the lower surface of the top plate of the bucket (11).
And one or more slit-shaped oil return passages (20a) are provided at the lower end thereof. High pressure chamber (1
5) is formed between the inside of the body (13) and the plunger (14), and the elastic body (16) is located in the high pressure chamber so as to urge the body (13) outward from the bucket (11). The plunger (14) is provided with an oil hole (14a) for introducing oil into the high pressure chamber (15). Also, a check valve (1 that controls the opening and closing of the oil hole)
7) and a check valve cage (18) are provided in the high pressure chamber. Through the oil hole (14a), adjacent to the high pressure chamber (15), the plunger oil reservoir chamber (19) is formed in a portion defined by the plunger (14) and the lower surface of the bucket top plate.
a) is provided. Further, a bucket oil reservoir (19b) is provided in a portion defined by the bucket (11), the sleeve (12), the body (13) and the plunger (14), and the plunger oil is provided by the communication groove (11d). It communicates with the reservoir chamber (19a). Furthermore, the bucket (1
In 1), an oil hole (11c) for introducing oil from the outside is provided. In this configuration, the slit-shaped oil return passage (20a) is connected to the body (1) from the inside of the high pressure chamber (15).
It serves as a short-circuit path for returning the oil leaking into the gap between the plunger (14) and the plunger (14) to the bucket oil reservoir (19b) without flowing into the bucket oil reservoir (19b).

Although FIG. 1 shows an example in which the ring-shaped member (20) is provided separately from the plunger (14), in the present invention, the ring-shaped member (20) is not provided and the plunger (14) is integrated. It is also possible to provide an oil return passage (20a) on the side wall.

Effect of the Invention According to the present invention, the required oil amount in the plunger oil reservoir chamber (19a) is provided by providing the leaked oil collecting means (20a) at the sliding portion between the body (13) and the plunger (14). As a result, it is possible to reduce the weight of the valve train by resolving the malfunction that occurred in the past when restarting after stopping the engine and forming the oil reservoir chamber to the minimum required size. It is possible to exert a great effect that it can contribute to.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing an embodiment 1 of the present invention,
FIG. 4 is an explanatory sectional view and a layout showing a conventional example, and FIG. 4 is an explanatory sectional view showing the same operation. Reference numerals in the drawings indicate the following members, respectively. (1): Hydraulic lash adjuster (2): Cylinder head, (3): Cam (4): Valve, (11): Bucket (12): Sleeve, (13): Body (14): Plunger, (15): High pressure chamber (16): Elastic body, (17): Check valve (18): Check valve cage, (20a): Oil return passage

Claims (3)

[Scope of utility model registration request] 1. A bucket (11) slidably fitted in a support hole of a cylinder head, a sleeve (12) adapted to be coupled at an inner surface of the bucket, and a sleeve (12) slidable on an inner cylindrical portion of the sleeve. A bottomed hollow cylindrical body (13), which is freely supported and whose bottom is in contact with the valve shaft end, and whose opening end is open inside the bucket, and a bottomed hollow cylinder having an oil hole in the bottom. A plunger (14) which is opened in the body toward the top plate side of the bucket and is slidably fitted into the body inner cylinder portion, and a high pressure chamber is defined by the body inner surface and the plunger. A plunger oil reservoir chamber (19a) is defined by the plunger and the top plate portion of the bucket, and a bucket oil reservoir chamber (19b) is defined by the plunger, the body, the sleeve and the bucket, and the bucket oil reservoir is defined. The room is the Plunger A direct-acting hydraulic rush tank with a structure in which the reservoir is communicated with a communication groove (11d) provided in a top plate portion of the bucket, and an oil hole (11c) for introducing oil is provided in the bucket. In the star, an oil return passage (20) communicating with the plunger oil reservoir (19a) is provided at a portion of the outer periphery of the plunger (14) that slides with the body (13).
A direct-acting hydraulic lash adjuster characterized in that one or more a) are provided. 2. A direct-acting hydraulic lash adjuster according to claim 1, wherein the oil return passage is a notched slit. 3. A ring-shaped member (20) is interposed between the plunger and the top plate portion of the bucket, and an oil return passage (20a) is provided at a joint between the ring-shaped member and the plunger. A direct-acting hydraulic lash thruster according to claim 1, characterized in that the utility model is registered.