JPS6347606Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic lifter provided in a valve mechanism of an internal combustion engine for an automobile.

[Prior art] In a valve operating mechanism in which a rocker arm is slidably supported, 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 not expanded or contracted or driven due to temperature changes. In order to automatically absorb gaps caused by wear of transmission parts, a hydraulic lifter is usually incorporated into the rocker arm to improve durability and reduce noise.

Typical hydraulic lifters built into conventional rocker arms are shown in Figures 1 and 2.
A device as shown in the figure has been proposed (Japanese Unexamined Patent Publication No. 53
−16112). In this device, a plunger 2 and a body 3 are assembled as a set in a rocker arm 1, a high pressure chamber 4 and an oil chamber 5 for supplying oil to the high pressure chamber 4 are formed, and a check ball 6 and a check ball spring 7 are connected to a check valve. The required amount of oil is supplied from the oil chamber 5 to the high pressure chamber 4 via the oil chamber 5 and sealed therein, and the body 3 is projected toward the cam 8 or the valve 9 to fill the gap therebetween. As described above, the conventional hydraulic lifter has a two-stage structure including the oil chamber 5 and the high pressure chamber 4, and the plunger 2, body 3, etc. are incorporated into the rocker arm 1 as a unit. Creating a two-stage hydraulic lifter requires a more complex structure, an increase in the number of parts, and an increase in weight. Therefore, it is important to achieve maintenance-free, low-noise, and good motion characteristics by reducing inertia. This becomes a disadvantageous element for the desired valve mechanism. Therefore, in order to meet these demands in a valve train, it is desirable to have a single-stage hydraulic lifter.
Various means and methods have been proposed for this one-stage system (for example, Japanese Patent Application Laid-Open No. 55-14914 discloses a single-stage system, but since the valve opens and closes in the rocking direction of the rocker arm, the checker ball (There is a risk that the valve may open unnecessarily due to the inertial force of be.

[Problems to be solved by the invention] In other words, the invention aims to simplify the hydraulic lifter, make it maintenance-free, reduce noise, and reduce the weight of the hydraulic lifter in order to meet the various performances desired for the above-mentioned valve mechanism. The purpose of this is to improve the motion characteristics of the valve train mechanism.It has a simple structure, is small in weight, and is less susceptible to the inertia of the valve body when the rocker arm swings, ensuring reliable operation. The object of the present invention is to provide a hydraulic lifter that can be used.

[Means for Solving the Problems] In order to achieve this object, in the hydraulic lifter for an internal combustion engine of the present invention, a tip-shaped plunger is brought into direct contact with a valve stem or a cam, and the plunger is directly brought into contact with a recess of a rocker arm. A single-stage hydraulic lifter is constructed by being slidably inserted into the hydraulic lifter. A high pressure chamber is formed by the inner surface of the plunger and the inner surface of the rocker arm recess, and an oil passage is connected to the high pressure chamber, which is bored from the rocker shaft side to the high pressure chamber side and extends approximately in the radial direction of the rocker arm swing. A check valve for stopping the flow of oil from the high pressure chamber side to the rocker shaft side is provided in the passage, with its opening and closing direction being approximately in the radial direction of the rocker arm swing. In addition, the opening of the oil passage to the high pressure chamber is provided at a position outside the sliding range of the plunger, and the inner surface of the rocker arm on the outlet side of the recess from the opening is restrained from excessive movement of the plunger to the back of the recess. A stopper is provided.

[Function] In a hydraulic lifter having such a structure, when oil is supplied from the oil passage to the high pressure chamber, the plunger protrudes from the recess so as to automatically fill the gap between it and the valve stem or cam. move in the direction. At this time, oil is sealed in the high pressure chamber by the check valve, so that the plunger is fixed to the rocker arm while filling the gap. By providing a check valve in the oil passage and making the hydraulic lifter one stage, the structure of the hydraulic lifter is simplified without impairing the function of the hydraulic lifter, making it maintenance-free and reducing noise. Further, by simplifying the structure, the weight of the hydraulic lifter is reduced, and the inertia of the hydraulic lifter portion is reduced, thereby improving the motion characteristics of the valve mechanism. In this case, since the check valve opens and closes approximately in the radial direction of rocker arm rocking, the inertial force acting on the check valve when rocker arm rocking is slidably received by the passage wall, and this inertial force has a negative effect on valve opening and closing. Opening/closing operation is reliable. In addition, the opening of the oil passage to the high pressure chamber is located at a position that does not interfere with the sliding range of the plunger, so oil supply is not obstructed no matter where the plunger is located.
In addition, a stopper is provided on the inner surface of the rocker arm, so
This prevents the plunger from moving to the opening and blocking the oil communication path, thereby stably supplying and sealing oil into the high pressure chamber, and at startup when the oil supply pressure is still insufficient. Even in this case, the plunger is prevented from being largely deviated from the predetermined position, and stable and reliable operation of the hydraulic lifter can be achieved.

[Embodiments] Hereinafter, preferred embodiments of the hydraulic lifter for an internal combustion engine of the present invention will be described with reference to the drawings.

FIG. 3 shows a hydraulic lifter according to an embodiment of the present invention. In the figure, 10 is a valve assembled to a cylinder head 11, and 12 is a cam that rotates together with a camshaft 13. Valve 10 and cam 1
A rocker arm 16 rotatably supported around a fixed rocker shaft 15 is provided between the two to form a valve operating mechanism. One end of the rocker arm 16 is brought into contact with the cam 12, and the other end is connected to the valve 10 through a hydraulic lifter 17 built into the other end.
is in contact with the top surface of the Note that the valve 10 is urged upward by the valve spring 14, and is closed when it is not pushed down by the rocker arm 16.

A cylindrical recess 18 is formed in the rocker arm 16, and a cylindrical plunger 19 with a bottom is inserted into the recess 18. A high-pressure chamber 20 is formed in the inner surface of the plunger 19 by the inner surface of the recess 18 of the rocker arm 16, in which oil is sealed. The plunger 19 is slidably fitted into the recess 18, and the clearance therebetween forms a lubricating oil film that prevents the oil sealed in the high pressure chamber 20 from escaping and allows the plunger 19 to slide smoothly. Clearance has been kept as low as possible.
The outer surface of the bottom of the plunger 19 is brought into contact with the top of the valve 10, and a return spring 21 made of a compression spring is interposed between the inner surface of the bottom and the upper surface of the recess 18.

The bottom outer surface of the plunger 19 is formed in a stepped shape, and a portion with a smaller diameter below the step portion 22 protrudes downward. A snap spring 23 is fitted into a groove at the lower part of the inner surface of the recess 18.
The snap ring 23 is connected to the stepped portion 2 of the plunger 19.
2 hits the snap spring 23,
It serves to prevent the plunger 19 from coming off.

The upper inner surface of the recess 18 is formed in a stepped shape, and the step 24 can come into contact with the upper end surface of the plunger 19 when the plunger 19 moves upward. Therefore, the stepped portion 24 serves as a stopper against the movement of the plunger 19 in the direction opposite to the outlet of the recess 18 .

An oil passage 25 formed within the rocker arm 16 is connected to the high pressure chamber 20 . The oil passage 25 is connected to the high pressure chamber 20 at one end, and is connected to an oil passage 26 in the rock shaft 15 formed by the hollow structure of the rock shaft 15 at the other end.
7. The oil passage 25 is
It is formed to extend substantially in the radial direction of rocker arm swing, and is formed straight over the entire length, with a stepped portion 28 having a reduced diameter toward the high pressure chamber 20 side formed in the middle. High pressure chamber 2 after diameter
0, and opens above the step 24 of the high pressure chamber 20. Therefore, the opening 29 is located above the step 24 as a stopper of the plunger 19.

A check valve 30 is provided in the middle of the oil passage 25 so that its opening and closing direction is substantially in the radial direction of the rocker arm swing. The check valve 30 includes a check ball 31 made of a steel ball, a check ball spring 32 provided between the check ball 31 and the stepped portion 28 and urging the check ball 31 toward the rocker shaft 15, and a check ball spring 32 that biases the check ball 31 toward the rocker shaft 15. Check valve seat 3 to stop movement
It consists of 3. The check valve seat 33 is press-fitted into the oil passage 25, and a hole 34 is formed in the check valve seat 33 so that both sides of the check valve seat 33 communicate with each other. This hole 3
The check ball 31 is pressed by the check ball spring 32 so as to close the check ball 4.

The locking arm 16 is swung by about 15 degrees with respect to the fixed locking shaft 15, but the oil passage 25 and the oil passage 2 inside the locking shaft 15 are
The hole 27 bored in the rocker shaft 15 communicating with the oil passage 25 and the oil passage 26 is formed in such a size and position that it does not cut off the communication between the oil passage 25 and the oil passage 26. The drilling process of the oil passage 25 is performed from the rock shaft 15 side toward the high pressure chamber 20 side. Therefore, there is no need for a machining hole and its blind plug on the high pressure chamber 20 side, as in the case of machining from the high pressure chamber 20 side.

In addition to the hole 27, the rock shaft 15 includes:
A hole 35 for supplying lubricating oil from the oil passage 26 is bored in the rotating and sliding portion of the rocker shaft 15 and the rocker arm 16. This hole 35 is
It is provided at an appropriate position that does not communicate with the processing hole 36 of the oil passage 25.

Although not shown, engine oil is sent from the oil pump to the oil passage 26 formed in the hollow part of the rocker shaft 15 through the oil gear gallery of the cylinder block and the oil passage of the cylinder head 11.

Next, the operation of the hydraulic lifter for an internal combustion engine of the present invention constructed as described above will be described below.

The oil sent to the oil passage 26 of the rock shaft 15 is sent to the high pressure chamber 20 through the oil passage 25. The oil filled in the high pressure chamber 20 becomes high pressure when the plunger 19 is pressed by the valve 10, and this pressure is transmitted to the check valve 30, pushing the check ball 31 toward the rocker shaft 15 and opening the hole. 34 is closed, and high pressure oil is sealed in the high pressure chamber 20. Since oil is an incompressible fluid, when oil is sealed in the high pressure chamber 20, the driving force transmitted from the cam 12 to the rocker arm 16 is directly transmitted to the valve 10 via the oil in the high pressure chamber 20 and the plunger 19. be done.
Now, the plunger 19 in this driving force transmission system
When a gap is about to occur between the valve 10 and the valve 10, the pressing force of the plunger 19 by the valve 10 decreases, and the oil pressure in the high pressure chamber 20 decreases. When the oil pressure becomes smaller than the value obtained by subtracting the urging force of the check ball spring 32 from the pressure of the oil sent through the oil passage 25, the check ball 3
1 is pushed toward the high pressure chamber 20, the hole 34 opens, and the high pressure chamber 20 is replenished with oil. When oil is replenished and the oil pressure in the high pressure chamber 20 is raised to the appropriate pressure again, the check ball 31 closes the hole 34 and the oil is trapped. Since the oil supply pressure from the oil passage 25 is constantly applied during engine operation, the oil pressure in the high pressure chamber 20 is automatically controlled to be maintained at a constant value by the action of the check valve 30. be done. Oil passage 26 in the rock shaft 15
The oil supply pressure from the oil passage 26 to the cam 12 is
The oil passage 25 itself has an appropriate volume, so the oil passage 25 is injected toward each part of the high pressure chamber 20
Since the oil passage 25 has a function as an oil supply chamber as well as a buffer chamber, fluctuations in the oil pressure in the oil passage 25 are kept considerably suppressed. Then, oil is sealed into the high pressure chamber 20 by the check valve 30, so that the high pressure chamber 2
The propagation of pressure fluctuations into zero is prevented. Hyperbaric chamber 2
By controlling the oil pressure at 0 to a constant value, the plunger 19 is pressed against the valve 10 with a constant pressing force, and the plunger 19 and the valve 1
Gaps that tend to occur due to wear, inertia of drive transmission parts, etc. during zero are automatically absorbed. By preventing the occurrence of gaps, the cam 12
The driving force is smoothly and reliably transmitted to the valve 10 via the rocker arm 16 and the hydraulic lifter 17. In this way, in the conventional two-stage hydraulic lifter, the oil passage 25 is provided with a function as an oil supply chamber, and the oil passage 25 is provided with a check valve 30.
By providing the hydraulic lifter 17, the hydraulic lifter 17 has a single-stage structure including only the plunger 19 constituting the high pressure chamber 20, and the structure of the hydraulic lifter 17 is simplified without impairing the gap absorption function. By simplifying the structure, the number of parts is reduced compared to the case of a complicated structure, and operation reliability is improved and maintenance-free operation can be achieved easily. Further, by simplifying the structure, the hydraulic lifter can be made smaller or its mass can be easily reduced, the inertia force is reduced, and the motion characteristics of the rocker arm 16 against high-speed swinging are improved.

Further, the oil passage 25 extends in a direction substantially perpendicular to the rocker arm swing direction (the direction of the circular arc trajectory of the rocker arm), and the check ball 31 is designed to open and close in a direction perpendicular to the rocker arm swing direction. The inertial force acting on the rocker arm 31 in the rocking direction is supported by the wall surface of the oil passage 25, and the opening and closing of the check ball 31 is not adversely affected by the inertial force in the rocker arm rocking direction.

In the hydraulic lifter of the present invention having such a function, oil must be smoothly supplied and sealed into the high pressure chamber 20 in order to stably exhibit its gap absorbing function. opening 2
Since the stopper 24 of the plunger 19 is provided below the plunger 9, the sliding portion of the plunger 19 does not interfere with the opening 29, and the opening 29 will not be blocked no matter where the plunger 19 is located. opening 29
is not blocked by the movement of the plunger 19, so the supply of oil to the high pressure chamber 20 is stably ensured without being hindered. In addition, the oil passage 25 is processed from the rock shaft 15 side,
Since the machining hole and its blind plug that remain on the high pressure chamber side when performing from the high pressure chamber 20 side are not required, the oil sealed in the high pressure chamber 20 is maintained in a stable sealed state without the risk of unnecessary leakage. Ru.

Furthermore, when the engine is started, the oil supply pressure from the oil pump has not yet risen sufficiently, and there is a possibility that the oil pressure in the high pressure chamber 20 and the position of the plunger 19 are insufficient. Even when the oil supply path is not blocked depending on the position of the plunger 19 as described above, and the movement distance of the plunger 19 is regulated by the stopper 24, the plunger 19 is moved in a desired position after starting. The plunger 19 is not started with a large deviation from the predetermined position, and the plunger 19 is quickly controlled to the predetermined position after starting, thereby stabilizing and facilitating the start.

In this way, in the hydraulic lifter of the present invention,
Although it has a simple one-stage structure, the high pressure chamber 20
A stable supply of oil to the engine and stable maintenance of the sealed state can be obtained, and stable and desirable operation can be obtained at all times, including during startup.

Next, FIG. 4 shows another embodiment in which the hydraulic lifter of the present invention is provided on the cam side. In this embodiment, the plunger 19 is configured as a flat plate with an enlarged diameter at the bottom, and a stepped portion 37 is formed on the outer cylindrical surface of the plunger 19, and is engaged with a snap ring 23 for preventing slippage. In this way, the shape of the plunger 19 is not particularly limited, and the material thereof is not particularly limited either. The plunger 19 may be made of a material other than iron or iron-based, and for example, ceramics or the like may be used for the purpose of weight reduction. Other configurations and operations are similar to those of the previous embodiment.

[Effects of the Invention] As explained above, when using the hydraulic lifter for an internal combustion engine of the present invention, the following various effects can be obtained.

First, a check valve is provided in the oil passage, and the high pressure chamber is constructed from the inner surface of the plunger and the inner surface of the rocker arm, making the hydraulic lifter a one-stage structure. This simplifies the structure without impairing the gap absorption function of the hydraulic lifter. It is possible to make the valve mechanism maintenance-free and reduce noise, and also to reduce the weight of the hydraulic lifter part, and to improve the motion characteristics for high-speed operation of the valve mechanism by reducing the weight of the hydraulic lifter part. I can do it.

In addition, since the oil passage is extended in a direction substantially perpendicular to the rocker arm swing direction and the check ball is opened and closed in a direction substantially perpendicular to the rocker arm swing direction, inertia in the rocker arm swing direction acts on the check ball when the rocker arm swings. is received by the wall surface of the oil passage, and the check ball will not open or close unnecessarily due to inertial force.

In addition, the opening of the oil passage to the high pressure chamber is placed in a position that does not interfere with the sliding part of the plunger, allowing for a stable supply of oil.A check valve is provided in the oil passage to prevent oil from entering the high pressure chamber. In addition to preventing pressure fluctuations from propagating, the processing of the oil passages has also prevented the creation of any points in the high pressure chamber that may cause oil leakage, making it possible to fill the high pressure chamber with stable oil, ensuring a reliable and stable flow. Hydraulic lifter operation can be obtained with

Furthermore, a plunger stopper is provided on the inner surface of the rocker arm to visually control the movable range of the plunger, so even if the oil supply pressure is insufficient during startup, the plunger can be quickly moved to a predetermined position and controlled. This also has the effect of making it easier and more stable.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a valve mechanism that incorporates a conventional two-stage hydraulic lifter on the cam side, and Figure 2 shows a valve mechanism that incorporates a conventional two-stage hydraulic lifter on the valve side. 3 is a vertical sectional view of a valve mechanism incorporating a hydraulic lifter for an internal combustion engine on the valve side according to an embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of a hydraulic lifter according to an embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view of a valve mechanism installed on the cam side. 10... Valve, 11... Cylinder head, 1
2...Cam, 13...Camshaft, 14...Valve spring, 15...Rotsukashaft, 16
...Lotsuka arm, 17...Hydraulic lifter, 18...
... recess, 19 ... plunger, 20 ... hyperbaric chamber,
21...Return spring, 24...Stepped portion as a stopper, 25...Oil passage, 29...Opening, 30...Check valve, 31...Check ball.

Claims (1)

[Scope of utility model registration request] A recess is formed in the rocker arm, a plunger that abuts either the valve or the cam is slidably inserted into the recess, and the inner surface of the plunger and the inner surface of the rocker arm form a high pressure chamber in which oil is sealed; An oil passage connecting the high pressure chamber and an oil passage in the rocker shaft is formed in the rocker arm so as to extend from the rocker shaft side toward the high pressure chamber side and approximately in the radial direction of rocker arm rocking. A check valve for preventing backflow of oil from the inside of the high pressure chamber to the rocker shaft side is provided in the oil passage extending in the radial direction so that its opening/closing direction is approximately in the radial direction of rocker arm rocking. An opening of an oil passage extending into the high pressure chamber is provided at a position out of the sliding range of the plunger, and
A hydraulic lifter for an internal combustion engine, characterized in that a stopper for sliding the plunger in a direction opposite to the opening side is provided on the inner surface of the recess on the outlet side of the recess than the opening.