JPH0244002Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a rocker arm provided in a valve mechanism of an internal combustion engine, and particularly relates to a rocker arm having a built-in hydraulic lifter.

Prior Art In a valve train mechanism in which a rocker arm is pivotally supported so that it can swing, a cam is engaged with one end of the rocker arm to swing the rocker arm, and the other end operates a valve, the valve is expanded and contracted due to temperature changes and drive transmission is performed. A hydraulic lifter is incorporated into the rocker arm to automatically absorb gaps caused by parts wear, etc., which ensures smooth transmission of valve driving force, improved durability, and reduced noise.

Conventionally, when assembling a hydraulic lifter into a rocker arm, the hydraulic lifter was filled with oil, the hydraulic lifter was inserted into the mounting hole of the rocker arm, and then the hydraulic lifter was pressurized to retract it to the mounting position. When the hydraulic lifter is pressurized, the check valve installed inside the hydraulic lifter closes, so it takes a considerable amount of time and pressure to retract the hydraulic lifter to the installation position, which poses a problem in ease of assembly. It was hot.

Purpose of the invention In order to solve the above-mentioned problems, the present invention improves ease of assembly by making it possible to easily retract the hydraulic lifter to a predetermined installation position in a short time after the hydraulic lifter is installed in the rocker arm. The purpose is to

Structure of the Invention In the rocker arm with a built-in hydraulic lifter of the present invention that meets this purpose, an elastic body insertion part is formed at the bottom of a recess in the rocker arm formed for incorporating the hydraulic lifter, and an elastic body is inserted into the rocker arm, and the elastic body has a A service hole is provided in the hydraulic lifter that faces toward the check valve, and is normally closed by elastic deformation due to the insertion of an elastic body so that at least no air can flow, and the bottom surface of the recess and the plunger are In between, a cap member is provided which holds the elastic body in the elastic body insertion part and has a guide hole that communicates between the service hole and the inside of the low pressure chamber, and a communication hole is provided in the rocker arm that communicates the service hole with the outside of the rocker arm. is provided.

Effect of the invention In such a rocker arm with a built-in hydraulic lifter, the service hole of the elastic body is directed toward the check valve, and the communication hole of the rocker arm and the guide hole of the cap member are located at a position where they can communicate with the service hole of the elastic body. When assembling the hydraulic lifter into the rocker arm, insert a thin rod (tool) from the outside of the rocker arm into the service hole through the communication hole, and then insert it through the guide hole of the cap member from the service hole to intentionally close the check valve. It becomes possible to open. Therefore, when the hydraulic lifter is assembled into the rocker arm and then retracted to the predetermined mounting position, the check valve can be kept open, and when the check valve is open, oil can easily move within the hydraulic lifter. Therefore, the hydraulic lifter can be easily retracted, the time required for retraction is shortened, and the pressing force required for retraction is reduced. In addition, if the thin rod is pulled out after shrinking to the predetermined mounting position, the injection hole of the elastic body will be sufficiently closed due to the elastic deformation caused by the insertion of the elastic body.
During normal hydraulic lifter operation, air is prevented from entering through the service hole, and oil is refilled and sealed into the high-pressure chamber smoothly as before, allowing gaps in the valve train to be absorbed with precision. Further, since the elastic body is held within the elastic body insertion portion by the cap member after being inserted into the elastic body insertion portion, there will be no problem such as falling off when the thin rod is inserted.

Effects of the invention By inserting an elastic body with a service hole, it is possible to maintain the valve train gap absorbing function of the hydraulic lifter, while making it easier to reduce the hydraulic lifter to a predetermined mounting position when assembling it. Assembling time can be shortened, pressing force can be reduced, and assembling performance can be improved. Furthermore, the cap member can reliably hold the elastic body at a desired position.

Embodiments Hereinafter, preferred embodiments of the rocker arm with a built-in hydraulic lifter of the present invention will be described with reference to the drawings.

1 to 5 show a rocker arm with a built-in hydraulic lifter according to an embodiment of the present invention. In the figure, 1 is a rocker arm, and the rocker arm 1 is swingably supported by a rocker shaft 2.
One end of the rocker arm 1 is brought into contact with a cam 3, and a hydraulic lifter 4 is incorporated into the other end, and the hydraulic lifter 4 is brought into contact with the head of a valve 6 which is urged upward by a valve spring 5.

The hydraulic lifter 4 is installed in a recess 7 formed in the rocker arm 1 and opening downward. The recess 7 includes a plunger 8 and a plunger 8.
A body 9 slidably provided between the inner peripheral surface of the recess 7 and the inner peripheral surface of the recess 7 is inserted. A low pressure chamber 10 is formed by the plunger 8 and the recess 7, and a high pressure chamber 11 is formed by the plunger 8 and the body 9. Oil is introduced into the low pressure chamber 10 from an oil passage 12 in the rocker shaft 2 through an oil passage 13 formed in the rocker arm 1, and oil is introduced from the low pressure chamber 10 into the high pressure chamber 11 through a communication hole 14. A check valve 15 is provided between the low pressure chamber 10 and the high pressure chamber 11 and is capable of closing the communication hole 14, thereby preventing oil from flowing back from the high pressure chamber 11 to the low pressure chamber 10. The check valve 15 is composed of a check ball 16 that opens and closes the communication hole 14, a check ball spring 17 that urges the check ball 16 toward the communication hole 14, and a retainer 18 that holds the check ball spring 17. Further, the high pressure chamber 11 is provided with a return spring 19 that pushes up the plunger 8 with respect to the body 9.

A cap member 20 made of a disc-shaped steel plate as shown in FIGS. 2 and 3 is interposed between the upper end of the plunger 8 of the hydraulic lifter 4 and the bottom surface of the recess 7 of the rocker arm 1. Member 20
A guide hole 21 consisting of a through hole is bored in the center of the guide hole 21 .

A recess 22 is formed in the bottom 7a of the recess 7 as an elastic body insertion part that is further recessed from the bottom surface of the recess 7. An elastic body 23 is inserted into the elastic body insertion portion 22, and the elastic body 23 is formed to have a volume larger than the elastic body insertion portion 22 in a free state. A service hole 24 consisting of a through hole is provided in the center of the elastic body 23, as shown in FIGS. 4 and 5.
The service hole 24 is located at the bottom of the check valve 1.
It is perforated in the direction toward 5. Further, the service hole 24 is normally closed by elastic deformation due to the insertion of the elastic body 23 to the extent that at least air circulation can be prevented. The degree of this blockage may be such that oil oozes out as long as air suction can be blocked. Therefore, in a free state, the elastic body 23 has a cross-sectional shape, a longitudinal cross-sectional shape, or both larger than the recess 22, and the service hole 24 is formed as described above due to elastic deformation caused by insertion thereof. It is formed in a size large enough to be occluded. And this elastic body 23
The cap member 20 allows the elastic body insertion portion 22 to
held within.

Bottom part 1a of elastic body insertion part 22 of rocker arm 1
A communication hole 25 is provided in which the service hole 24 communicates with the outside of the rocker arm 1. Communication hole 2
5. The service hole 24 and the guide hole 21 are formed on the same axis and facing in the same direction, and the direction is set toward the upper end surface of the check valve 15, more specifically, the check ball 16.

The operation of the rocker arm with a built-in hydraulic lifter having the above-mentioned configuration will be described below.

First, the gap absorption function of the valve train of the hydraulic lifter 4 will be explained. During engine operation, the cam 3 rotates as the camshaft rotates, causing the rocker arm 1 to swing, thereby opening and closing the valve 6 via the hydraulic lifter 4. When the cam 3 is at the lift portion 3a, the reaction force from the valve spring 5 from the valve 6 is applied to the hydraulic lifter 4, and the pressure in the high pressure chamber 11 in the hydraulic lifter 4 increases, causing the check valve 1 to rise.
5 is closed. Therefore, the hydraulic lifter 4 transmits the displacement amount of the cam 3 to the valve 6 without contracting. However, since there is a slight clearance between the inner diameter of the body 9 and the outer diameter of the plunger 8, a minimal amount of shrinkage occurs.
When the cam 3 comes to the position of the base circular part 3b,
Since no force is applied to the hydraulic lifter 4, the high pressure chamber 11
The pressure in the low pressure chamber 10 decreases, and the pressure in the low pressure chamber 10 decreases due to the force of the return spring 19. Therefore, the check valve 15 is opened, and the oil in the low pressure chamber 10 is replenished into the high pressure chamber 11, and the hydraulic lifter 4 is extended until the oil reaches zero lash. The hydraulic lifter 4 repeats the above-mentioned movement while the engine is operating, and is operated so as to always maintain zero latch, so that the gap in the valve train is automatically absorbed.

During operation of this hydraulic lifter 4, the service hole 24 of the elastic body 23 communicating with the low pressure chamber 10 is sufficiently closed by elastic deformation due to the insertion of the elastic body 23, so that air cannot enter or exit from the outside. The same good gap absorption function as the conventional device is maintained.

Next, the ease of assembling the hydraulic lifter 4 will be explained. After the hydraulic lifter 4 is inserted and assembled into the rocker arm 1, when retracting the hydraulic lifter 4 to a predetermined mounting position, the communication hole 25, the service hole 2
4. Since the guide hole 21 is formed on the same axis and facing the check valve 15, a thin rod (tool) can be inserted into the communication hole 2 from outside the rocker arm 1.
5. Pass the service hole 24 and guide hole 21 and place the tip on the check ball 16, and then tighten the check valve 1.
5 can be opened. The injection hole 24 of the elastic body 23 is normally closed by elastic deformation, but since the closure utilizes elasticity, a thin rod can be easily inserted into the service hole 24. Furthermore, since the elastic body 23 is supported within the elastic body insertion portion 22 by the cap member 20, it is held in a predetermined position even when the thin rod is inserted.

A thin rod (tool) inserted into the service hole 24
is guided by the guide hole 21 of the cap member 20, so the tip of the thin rod is aligned with the check ball 1.
It is reliably positioned in 6 directions. and,
By pushing the check ball 16 with a thin rod, the check valve 15 is maintained in an open state when the hydraulic lifter 4 is retracted, allowing free movement of oil between the high pressure chamber 11 and the low pressure chamber 10. Thus, the hydraulic lifter 4 can be easily retracted to a predetermined mounting position with a small force. Therefore, the time required for shrinking is shortened, and the pressing force required for shrinking is reduced.

As is clear from the above explanation, when using the rocker arm with a built-in hydraulic lifter of this embodiment, when installing the hydraulic lifter, it is possible to intentionally open the check valve by inserting a thin rod into the service hole of the elastic body. By keeping the check valve open, the hydraulic lifter can be easily retracted to the predetermined assembly position of the rocker arm, which shortens the time required for retraction and reduces the pressing force, improving assembly efficiency. This effect can be obtained.

In addition, by inserting a syringe needle into the service hole of the elastic body, oil can be directly injected into the low pressure chamber and high pressure chamber from outside the rocker arm after the hydraulic lifter is installed, allowing the hydraulic lifter to extend and retract while the check valve is open. This makes it possible to smoothly replace the air inside and the oil from the outside, and it is not necessary to fill it with oil before assembling, so it is possible to improve the assembling work efficiency.

Furthermore, by setting the service hole in the elastic body to an appropriate size, air that gets mixed into the oil passage in the low pressure chamber and rocker arm by intentionally opening the service hole can be released without reducing the oil pressure. Effects can also be obtained.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a part of a rocker arm with a built-in hydraulic lifter in cross section according to an embodiment of the present invention, Fig. 2 is an enlarged longitudinal sectional view of the cap of the device shown in Fig. 2 is a plan view of the device shown in FIG. 2, FIG. 4 is an enlarged vertical sectional view of the device shown in FIG. 1 in a free state of the elastic body, and FIG. 5 is a plan view of the device shown in FIG. 4. DESCRIPTION OF SYMBOLS 1... Locker arm, 1a... Bottom of elastic body insertion part, 2... Locker shaft, 3... Cam, 4...
...Hydraulic lifter, 6...Valve, 7...Recess, 7a
... Bottom of recess, 8 ... Plunger, 9 ... Body, 10 ... Low pressure chamber, 11 ... High pressure chamber, 15 ...
Check valve, 16...Check ball, 19
... Return spring, 20 ... Cap member, 21 ... Guide hole, 22 ... Elastic body insertion part,
23...Elastic body, 24...Service hole, 25...
Communication hole.

Claims (1)

[Scope of utility model registration request] A recess is formed in the rocker arm, a plunger and a body are inserted into the recess, a low pressure chamber is formed by the recess and the plunger, a high pressure chamber is formed by the plunger and the body, and oil from the high pressure chamber is formed between the high pressure chamber and the low pressure chamber. In a rocker arm with a built-in hydraulic lifter provided with a check valve to prevent backflow of fluid, an elastic body insertion part is formed at the bottom of the recess, and the elastic body is inserted into the rocker arm, and the elastic body is inserted through a hole in the direction toward the check valve. A service hole is provided which is normally closed so that at least no air flows through due to the elastic deformation of the elastic body, and the elastic body is held in the elastic body insertion portion between the bottom surface of the recess and the plunger, and the service hole is A rocker arm with a built-in hydraulic lifter, characterized in that a cap member having a guide hole that communicates between the hole and the inside of the low pressure chamber is provided, and a communication hole is provided in the rocker arm that communicates the service hole with the outside of the rocker arm.