JPH06185315A - Locker arm of valve system - Google Patents

Abstract

PURPOSE:To prevent backflow of oil in an oil reservoir and mixing of air in a high pressure chambereven when a shrinkage cavity and a blowhole formed at the time of manufacture are short-circuited in the oil reservoir of a comparatively small diametrical cylindrical port formed deep in a support port into which a hydraulic rush adjuster provided on the side of a valve rod of a locker arm used in a valve system of an internal combustion engine is inserted. CONSTITUTION:A locker arm 2 is made of alminium die-cast, and a shrinkage cavity and a blowhole are made inside. In the locker arm 2, by connecting a shaft port 17 into which a locker shaft is inserted and an oil reservoir formed deep in a rush adjuster support port on the side of a valve rod by an oil conduit, oil is supplied to a rush adjusted. In the state where the oil conduit 18 and the oil reservoir are short cut by the shrinkage cavity and the blowhole and are communicated through to each other, on the shaft part 17 of the oil conduit 18 and a connection hole 18b, a second check valve 25 is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve mechanism for an internal combustion engine, and more particularly, to an aluminum lash adjuster which automatically corrects a valve clearance by hydraulic pressure and elastic force of an elastic member. Die-cast rocker arm.

[0002]

2. Description of the Related Art A valve train in an internal combustion engine is generally susceptible to wear and thermal expansion, and the clearance between the valve and the valve changes during operation. Therefore, a hydraulic lash adjuster that properly corrects this gap has come to be used. An example of a valve mechanism including such a hydraulic lash adjuster is shown in FIG. In FIG. 2, the hydraulic lash adjuster 1 is fitted into a support hole 3 formed at one end of the rocker arm 2. The support hole 3 is formed as a cylindrical hole on the opening end side, and a cylindrical hole having a comparatively small diameter is formed as an oil reservoir 3b further inside. The body 4 of the hydraulic lash adjuster 1 has a hollow bottomed cylindrical shape, and is inserted into the support hole 3 with the bottomed portion being deep. The bottom surface of the body 4 is provided with an oil hole 5 that communicates the oil reservoir 3 a with the inside of the body 4. A plunger 6 is slidably fitted in the hollow inside of the body 4, and the other end of the plunger 6 protruding from the opening of the body 4 is in contact with a valve 7 for opening and closing a cylinder (not shown) (for intake, for example). It is touched. In the body 4, a space partitioned by the inner surface of the body 4 and the end surface of the plunger 6 constitutes a high pressure chamber 8 that communicates with the oil reservoir 3 a via the oil hole 5.

A first check valve 9 for opening and closing the oil hole 5 is provided in the high pressure chamber 8, and the first check valve 9 is provided.
Is a ball valve 10 that can be seated in the oil hole 5, a spring 11 that presses the ball valve 10 toward the oil hole 5, and a spring 11
And a plate seat 12 for supporting. Further, a spring 13 for pressing the plunger 6 toward the valve 7 is interposed between the plate seat 12 and the concave surface of the end surface of the plunger 6. Also, valve 7
A valve spring 14 is attached to the shaft portion of the valve 7, and is compressed when the valve 7 is actuated in the valve opening direction so that an elastic force acts in the valve closing direction. Moreover, the elastic force of the valve spring 14 is the spring 1
It is set to be larger than the elastic force of 3.

Further, in the rocker arm 2, an oil conduit 18 for supplying oil is bored in the rocker arm body 2a between a shaft hole 17 into which the rocker shaft 16 is inserted and the oil reservoir 3a. The ball 18a is press-fitted and closed in the vicinity of the open end. Also, the oil sump chamber 3
A and the oil conduit 18 inside the ball 18a are connected by an oil conduit 19. Therefore, the oil conduits 18 and 19 are formed in a substantially V shape. As a result, even if the oil in the oil conduit 18 flows backward toward the shaft hole 17 due to gravity when the engine is stopped, the oil in the oil conduit 19 and the oil in the oil sump chamber 3a are retained without flowing out. At the center, for example, of the surface of the rocker arm 2, a chip 21 that is in contact with the cam 20 and that rotates the rocker arm 2 around the rocker shaft 16 in accordance with the rotation of the cam 20 is attached.

Since this valve operating mechanism is constructed as described above, the oil supplied is guided from the region of the rocker shaft 16 to the oil reservoir 3a via the oil conduits 18 and 19, and the first check valve 9 is provided. Through the oil hole 5 into the high pressure chamber 8. When the rocker arm 2 is pressed by the cam surface of the cam 20 by the operation of the internal combustion engine, the valve 7 is pushed out via the hydraulic lash adjuster 1. At the time of this operation, the first check valve 9 is seated in the oil hole 5 to close it, so that the spring 13 is contracted and the oil trapped in the high pressure chamber 8 is compressed to exhibit rigidity. . As a result, the plunger 6 operates together with the rocker arm 2 and compresses this against the elasticity of the valve spring 14, so that the valve 7 is pushed out and opened.

Further, when the rocker arm 2 is actuated in the opposite direction by the rotation of the cam 20 during the valve closing operation, the elasticity of the valve spring 14 in the compressed state causes the plunger 6 to act in the same direction, thereby following the actuation of the rocker arm 2. Then, the valve 7 is seated in the cylinder opening and is closed. In this state, the force of the valve spring 14 on the plunger 6 ceases to act. Therefore, the plunger 6 slides toward the valve 7 due to the repulsive force of the spring 13 in the contracted state,
It is possible to make a correction so as to eliminate the gap between the valve 7 and the plunger 6 which is contracted due to thermal deformation or the like.

[0007]

By the way, the rocker arm 2 used in such a valve operating mechanism is an aluminum die-cast product usually manufactured by die-casting. The manufacturing method is to blow the molten aluminum into the required shape of the molten aluminum at high speed and high pressure, so that the molten metal near the inner wall of the die casts first and gradually solidifies in the center. Has become. Therefore, when contracting, stress is generated in the outer portion and the inner portion in the rocker arm body, and as shown in FIG. 3, shrinkage cavities 22 due to shrinkage are often formed inside, and such shrinkage cavities 22 are formed at both ends. Is formed into a sharp, substantially long hole shape. Furthermore, in order to blow the molten metal at high pressure, blow holes 2 by gas are used.
3 will also be formed. The shrinkage cavity 22 and the blow hole 23 are likely to be formed near the center of the rocker arm body, but in this region, in the later step, the oil conduit 1 as described above is formed.
8, 19 and the support hole 3 and the oil reservoir 3a are drilled. Therefore, structurally, one end of the shrinkage cavity 22 or the like is cut when the oil conduit 18 is drilled, and the other end is cut when the oil reservoir chamber 3a or the oil conduit 19 is processed, so that an intermediate portion of the oil conduit 18 is cut. The oil reservoir 3a and the like communicate with each other, resulting in a short circuit.

Then, depending on the mounting angle of the valve mechanism,
When the internal combustion engine is stopped, the oil in the oil reservoir 3a and the oil conduit 19 is gravitationally moved from the oil conduit 18 through the shrinkage cavity 22 to the shaft hole 1
There is a problem that the oil flows back up to 7, causing a shortage of oil when the engine is restarted. In addition, in this case, since the air flows into the oil sump chamber 3a due to the oil escape, the oil passes through the oil conduits 18 and 19 when the engine is restarted and the oil is stored in the oil sump chamber 3a.
When the plunger 6 moves toward the valve 7, the air in the oil reservoir chamber 3a or the like is entrained in the oil and flows into the high pressure chamber 8 via the first check valve 9 when the plunger 6 moves toward the valve 7. 9
Will be blocked and will be compressed. in this case,
The pressure in the high-pressure chamber 8 decreases due to the compression of the air, and the oil in the high-pressure chamber 8 does not exhibit rigidity. Therefore, there is a problem in that the plunger 6 and the valve 7 do not operate together and the hydraulic lash adjuster 1 does not function as a shock absorber between the rocker arm 2 and the valve 7. The wall thickness of the rocker arm 2 is usually about 5 mm, but in particular, in order to increase the strength of the rocker arm 2 itself or to attach the chip 21, the rocker arm 2 is formed to have a wall thickness of about 6 mm or more. In this case, the shrinkage cavity 22 is more easily formed, and this problem is more likely to occur.

As a conventional countermeasure against such a problem, for example, there is a means for inserting an aluminum pipe into the oil conduit 18 to cut off the communication between the shrinkage cavity 22 and the oil conduit 18. However, such a method is not preferable because it requires high precision in manufacturing the pipe, resulting in an increase in manufacturing cost and an increase in weight. Further, there is a method of impregnating the resin after the processing of the oil conduit 18 of the rocker arm 2 and the oil reservoir 3a is completed and injecting the resin into the shrinkage cavity 22 and the blow hole 23 to embed the resin. Since it is significantly different from aluminum and the like, it is not practical in consideration of the variety of use environments of the internal combustion engine. In addition, means for fitting an oil sump cap to the inner wall surface of the oil sump 3a, means for speeding up the supply of oil to the hydraulic lash adjuster 1 and the like are conceivable, but the mechanism becomes complicated. However, there were problems such as an increase in weight and an increase in manufacturing cost.

In view of such circumstances, it is an object of the present invention to provide a rocker arm of a valve mechanism which can easily and inexpensively prevent oil from flowing out from an oil reservoir or an oil conduit.

[0011]

A rocker arm of a valve mechanism according to the present invention opens and closes with a first check valve 9 between a support hole portion of the rocker arm and a hydraulic lash adjuster fitted in the support hole portion. The oil reservoir that communicates with the high pressure chamber in the hydraulic lash adjuster is formed through the oil hole that controls the oil, and the oil conduit that is drilled in the rocker arm body from the rocker shaft fitting hole in the rocker arm. In the valve operating mechanism in which oil is supplied to the oil reservoir through the oil conduit, the oil conduit is short-circuited with the oil conduit in the oil reservoir or its vicinity by one of the shrinkage cavity and / or the blow hole to communicate with the oil conduit. The second check valve is arranged in the oil conduit upstream of the communication with the shrinkage cavity and / or the blow hole.

A plunger for opening and closing a valve urged by an elastic member is slidably fitted in a bottomed hollow body having an oil hole at the bottom, which is fitted in the support hole of the rocker arm. An oil reservoir is formed between the support hole and the bottom of the body, and a high pressure chamber communicating with the oil reservoir through an oil hole is formed between the inner wall of the body and the plunger. The opening and closing of the oil hole is controlled by the first check valve, so that the oil is supplied from the rocker shaft fitting hole in the rocker arm to the oil reservoir through the oil conduit bored in the rocker arm body. In the valve operating mechanism, the oil conduit is short-circuited and communicated with the oil conduit in the oil reservoir chamber or the vicinity thereof by the shrinkage cavity and / or the blowhole, and the communication section with the shrinkage cavity and / or the blowhole is formed. Upstream of It is characterized in that the second check valve in the conduit is disposed.

Further, the rocker arm is characterized by being an aluminum die-cast product.

Further, the second check valve is characterized in that it is arranged at a connection port with the rocker shaft fitting insertion hole of the oil conduit.

[0015]

[Operation] When the engine is stopped, the oil in the oil reservoir and the oil conduit is retained by the second check valve without flowing out,
Therefore, air does not flow into the oil reservoir or the oil conduit, and when the engine is restarted, the pressure of the high pressure chamber rises rapidly to obtain rigidity, and the hydraulic lash adjuster operates properly.

When the engine is stopped, the oil in the oil sump chamber and the oil conduit is held by the second check valve without flowing out, so that air does not flow into the oil sump chamber or the oil conduit and the engine is restarted. Upon startup, the high pressure chamber quickly rises in pressure to provide rigidity and the plunger and valve work together.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below with reference to FIG. 1. However, the same parts or members as those in the prior art described above will be designated by the same reference numerals and description thereof will be omitted. FIG. 1 is a cross-sectional view of a main part near a rocker shaft of a rocker arm.
In the rocker arm 2 shown in FIG. 1, an oil flow in the direction of the oil reservoir 3a is allowed, but an oil flow in the opposite direction is allowed at the communication port 18b of the oil conduit 18 with the shaft hole 17 into which the rocker shaft 16 is inserted. A second check valve 25 for preventing the above is installed. The second check valve 25 includes, for example, a ball valve 26 that can be seated in the communication port 18b and a spring 27 that elastically presses the ball valve 26 toward the communication port 18b.
And a plate seat 28 that supports one end of the spring 27.

This embodiment is constructed as described above,
Next, the operation will be described. Since the shrinkage cavity 22 and the blow hole 23 are formed in the main body of the rocker arm 2 manufactured by aluminum die casting as shown in FIG. 3,
By processing the oil conduits 18 and 19, the oil reservoir 3a, and the support hole 3 during the post-processing, the oil conduit 1 is inserted through the shrinkage cavity 22 and the like.
It is assumed that the middle part of 8 and the oil reservoir 3a (or the oil conduit 19) are short-circuited and are in communication with each other. Even in such a case, when the engine is in a stopped state, the oil in the oil reservoir 3a is short-circuited by the gravity through the shrinkage cavity 22 (the blow hole 23 in some cases) to communicate with the shaft from the oil conduit 18. Even if an attempt is made to backflow in the direction of the hole 17, the second check valve 25 is closed by the biasing force of the spring 27, so that backflow of oil is blocked and remains in the oil reservoir chamber 3a and the oil conduits 18 and 19. Therefore, air does not flow into the oil reservoir 3a and the oil conduits 18 and 19.

Therefore, when the engine is restarted, the oil reservoir 3a and the oil conduits 18 and 19 are filled with oil, so that the oil flowing from the first check valve 9 into the high pressure chamber 8 is Plunger 6 has valve 7
When moving in the direction, the required high pressure is obtained reliably and quickly, and the rigidity is exhibited. Therefore, the plunger 6 and the valve 7 operate together.

As described above, according to this embodiment, the rocker arm 2 is manufactured by aluminum die casting, and the shrinkage cavity 22 is formed inside.
Even if the blowhole 23 or the blowhole 23 is formed, the oil in the oil reservoir 3a and the oil conduits 18 and 19 remains without backflow when the engine is stopped, and air is introduced into the oil introduced into the high pressure chamber 8 at the time of restart. The rigidity can be maintained without being mixed. Therefore, the hydraulic lash adjuster 1 operates properly and also functions as a shock absorber. Even if the thickness of the rocker arm 2 exceeds 5 mm and the shrinkage cavity 22 is easily formed, the same function can be maintained.

The position of the second check valve 25 does not necessarily have to be formed at the connection port with the shaft hole 17 of the oil conduit 18, but the shrinkage cavity 22 communicating with the oil reservoir 3a.
Or upstream of the connection with the blowhole 23,
It may be an intermediate portion of the oil conduit 18. However, shaft hole 1
It is more preferable if it is provided at the connection port 18b with 7 because the amount of oil retained is maximized. Further, the communication portion of the shrinkage cavity 22 may be the oil conduit 19 in the vicinity thereof instead of the oil reservoir chamber 3a.
Needless to say, the hydraulic lash adjuster fitted with the rocker arm 2 is not limited to the above-mentioned one. The support hole 3 and the oil reservoir 3a form a support hole portion.

[0022]

As described above, in the rocker arm of the valve operating mechanism according to the present invention, the second check valve is arranged in the oil conduit, so that the oil from the oil conduit and the oil reservoir is stopped when the engine is stopped. Can be prevented, and the hydraulic pressure in the room can be controlled to a rigid state without air flowing into the high-pressure room at the time of restart.
Further, it can surely function as a shock absorber. Moreover, it is inexpensive and has a simple structure because it only requires an additional check valve.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a rocker arm according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a general valve mechanism.

FIG. 3 is a cross-sectional view of a connecting structure portion of a rocker arm and a hydraulic lash adjuster when the rocker arm is an aluminum die cast product.

[Explanation of symbols]

 1 Hydraulic lash adjuster 2 Rocker arm 3a Oil reservoir 6 Plunger 7 Valve 8 High pressure chamber 9 First check valve 16 Rocker shack 18 Oil conduit 22 Shrinkage cavity 25 Second check valve

Claims (4)

[Claims] 1. Inside a hydraulic lash adjuster through an oil hole whose opening and closing is controlled by a first check valve 9 between a support hole portion of a rocker arm and a hydraulic lash adjuster fitted in the support hole portion. Is formed in the rocker arm so that oil is supplied from the rocker shaft fitting hole in the rocker arm to the oil reservoir chamber through an oil conduit bored in the rocker arm body. In the valve operating mechanism, the oil conduit is short-circuited with the oil reservoir or the oil conduit in the vicinity thereof by the shrinkage cavity and / or the blowhole to communicate with the oil reservoir chamber and / or the blowhole. A rocker arm, wherein a second check valve is provided in the oil conduit upstream of the communication portion. 2. A plunger for opening and closing a valve urged by an elastic member is slidably fitted in a bottomed hollow body fitted with a support hole of a rocker arm and having an oil hole at the bottom. An oil reservoir is formed between the support hole and the bottom of the body, and a high-pressure chamber is formed between the inner wall of the body and the plunger to communicate with the oil reservoir through the oil hole. The opening and closing of the oil hole is controlled by a first check valve, and oil is supplied from the rocker shaft fitting insertion hole in the rocker arm to the oil reservoir through an oil conduit bored in the rocker arm body. In the valve operating mechanism, the oil conduit is short-circuited and communicated with the oil conduit in the oil reservoir chamber or in the vicinity thereof by the shrinkage cavity and / or the blow hole, and the oil cavity and / or the blow hole. Upstream of the communication part A rocker arm, in which a second check valve is provided in the oil conduit on the side. 3. The rocker arm according to claim 1, wherein the rocker arm is an aluminum die-cast product. 4. The rocker arm according to any one of claims 1 to 3, wherein the second check valve is arranged at a connection port with a rocker shaft fitting insertion hole of an oil conduit.