JP2003336507A - Rush adjustor for valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rush adjustor capable of preventing the sucking of air into a high pressure chamber and preventing the generation of noise. <P>SOLUTION: A pressure receiving member 12 is attached to the opening end 111a of a cylindrical lower plunger 111 on a joint side with an upper plunger 110, with the outer periphery of the pressure receiving member being sealed to the inner surface of the opening end 111a. A cylindrical elastic body 18 is attached in a sealed state between the opening end 111b on the opposite side from the bottom 10c of a body 10 and a bottom member 17 disposed on the upper surface of the bottom 10c of the body 10. A pressure receiving chamber 16 is divided as a sealed space by the upper half of the lower plunger 111 and the pressure receiving member 12, and the high pressure chamber 19 is divided as a sealed space by the lower half of the lower plunger 111 and the cylindrical elastic body 18. The both chambers are made to communicate with each other only by the movement of a ball of a reverse flow preventive means B. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism lash adjuster for an internal combustion engine such as an engine. The lash adjuster causes thermal expansion due to the temperature of the valve operating mechanism during operation of the engine valve operating mechanism. By absorbing the above, the valve clearance is maintained at almost zero, noise and gas blow-through are prevented, and stable operation of the valve operating mechanism is realized.

[0002]

2. Description of the Related Art Generally, in a valve train of an internal combustion engine,
It is necessary to provide a valve clearance in consideration of the expansion difference between the cylinder head and the valve operating mechanism due to heat. If the valve clearance is not appropriate, the valve surface of the valve may be separated from the valve seat, and abnormal noise may be generated during engine operation, or the generated horsepower may be lost due to gas blow-through. A valve clearance zero adjusting means using a lash adjuster is known as means for solving such a problem.

As this type of lash adjuster, there is known the following one used in, for example, an OHC type valve operating mechanism as shown in FIG. In the valve mechanism C, a cam 36 rotatably supported by a cam shaft is brought into contact with a swing arm 37, one end of the swing arm 37 is an intake / exhaust valve 38, and the other end is a lash adjuster 30.
Is contacted with the working end of. The intake / exhaust valve 38 has a valve spring 3
9 is provided, whereby the intake / exhaust valve 38 is biased toward the closing direction of the intake / exhaust port.

The lash adjuster 30 has a body 31.
And a plunger 32 slidably fitted inside the body 31. A high pressure chamber 33 is defined between the bottom side of the body 31 and the bottom side of the plunger 32 so that the high pressure chamber 33 can expand and contract in response to the sliding movement of the plunger 32. Further, inside the plunger 32, a reservoir chamber 34 into which hydraulic oil flows through oil passages 31a and 32b formed in the body 31 and the plunger 32 is formed, and the reservoir chamber 34 is formed by a check ball 35 as a backflow preventing means. It is openably and closably connected to the high pressure chamber 33.

While the engine is rotating, the swing arm 37 moves on the basis of the rotation of the cam 36 so that the lash adjuster 3 moves.
The intake / exhaust valve 38 is actuated by oscillating with the contact portion of the plunger 32, which is in contact with the operating end of the plunger 32, as a fulcrum. When the engine is stopped, the cam surface of the cam 36 contacts the swing arm 37 at an arbitrary position. Cam nose (protruding part of cam) 3
When 6a is in contact with the swing arm 37, the end of the swing arm 37 on the intake / exhaust valve side is pushed up by the urging force of the valve spring 39 that urges the intake / exhaust valve 38 in the closing direction. 37 and cam nose 3
The end of the swing arm on the lash adjuster 30 side rotates downward with the contact point with 6a as a fulcrum, and the plunger 32 of the lash adjuster 30 is always in a state in which an axial pressing force is applied. Therefore, if the stopped state continues for a long time, the body 31 and the plunger 32 of the lash adjuster 30 are stopped.
The oil in the high-pressure chamber 33 gradually leaks from the gap between and, and finally the volume of the high-pressure chamber 33 becomes the minimum state.

After that, the engine restarts and the cam 36
When the base surface 36b of arrives at the swing arm 37,
Since the lash adjuster 30 is released from the pressing force in the axial direction, the plunger 32 of the lash adjuster 30 is released.
Expands due to the force of a spring arranged in the high pressure chamber 33, the volume of the high pressure chamber 33 increases, and the high pressure chamber 33 moves to the reservoir chamber 34.
Is negative pressure. As a result, the check ball 35 is opened, and the oil in the reservoir chamber 34 is sucked into the high pressure chamber 33. At this time, in the reservoir chamber 34, the oil passages 31a and 32b are provided.
The oil is replenished through the. When the high pressure chamber 33 reaches a predetermined pressure (pressure during normal operation) again, the check ball 35 closes. In this state, the lash adjuster 30 will perform a normal expansion / contraction operation.

However, in the conventional structure, the high pressure chamber 33 is
Immediately after the engine is started, the oil passage 31 is removed from the reservoir chamber 34 and the gap between the body 31 and the plunger 32.
Oil containing air is rapidly sucked into the high pressure chamber 33 via a, 32b, etc., so that the high pressure chamber 33 becomes a so-called air damper state, and the swing arm 37 in the lash adjuster 30 by the valve operating system reaction force. The support position has moved. As a result, the zero adjustment of the valve clearance becomes unstable, the proper timing is deviated, and the valve operating mechanism C causes abnormal noise.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to prevent air from being sucked into the high pressure chamber of the lash adjuster and to suppress the generation of abnormal noise when the engine is stopped for a long period of time. It is to provide a lash adjuster that can.

[0009]

In order to solve the above problems, according to the invention of claim 1, a working fluid is introduced from a communication passage provided with a backflow prevention means to increase or decrease the internal volume to expand or contract the high pressure. A chamber, a plunger that is urged in a direction in which the valve clearance of the valve operating mechanism of the internal combustion engine is reduced to zero by increasing the volume of the high-pressure chamber, and a recess that slidably accommodates the plunger. A valve mechanism lash adjuster including a body, comprising: a reservoir chamber in which a high-pressure medium flows in and out from a high-pressure medium supply unit; and a pressure-receiving chamber capable of communicating with the high-pressure chamber via the communication passage, The reservoir chamber and the pressure receiving chamber are partitioned by a pressure receiving member capable of expanding into the pressure receiving chamber by the pressure of the high pressure medium in the reservoir chamber, and the high pressure chamber and the pressure receiving chamber are defined by the communication passage. Except that communicates internally with being sealed is summarized in that the working fluid is sealed.

In the present invention, when the engine is restarted after being stopped for a long time, the high-pressure medium is introduced from the high-pressure medium supply section into the reservoir chamber, and the pressure of the high-pressure medium causes the pressure receiving member to expand into the pressure receiving chamber. As a result, the pressure in the pressure receiving chamber rises, and when the pressure receiving chamber becomes higher in pressure than the high pressure chamber, the working fluid flows from the pressure receiving chamber into the high pressure chamber. Due to the inflow of the working fluid, the plunger is pushed up and the lash adjuster is extended as the high-pressure chamber having a high pressure expands.

According to a second aspect of the present invention, the plunger is disposed in the recess of the body, the high-pressure chamber is formed between the bottom of the body and the plunger, and the high-pressure chamber is disposed around the high-pressure chamber so as to move up and down. The gist of the present invention is to provide an expandable seal member whose ends are respectively connected to the plunger and the bottom surface of the high pressure chamber.

According to the present invention, the plunger is lowered,
Even when the pressure in the high-pressure chamber is higher than that in the pressure-receiving chamber, the high-pressure chamber is sealed around the periphery by the seal member, and the working fluid does not leak from the gap between the plunger and the body. Since the working fluid only leaks from the high pressure chamber to the pressure receiving chamber only through the communication passage, it is possible to prevent the pressure in the high pressure chamber from dropping sharply.

According to the third aspect of the present invention, the plunger is composed of an upper plunger and a cylindrical lower plunger. Inside the lower plunger, the pressure receiving chamber is provided on the upper plunger side by the inner wall having the communication passage. However, a high-pressure chamber is defined and formed on the bottom side, an opening end of the lower plunger on the upper plunger side is closed by the pressure receiving member, and a bottom member forming a bottom surface of the high-pressure chamber on the opening end on the bottom side. And a seal member connecting the lower plunger with the lower plunger, the lower plunger, the pressure receiving member, the seal member, the bottom member, and the backflow preventing means are integrally assembled. To do.

According to the present invention, the lower plunger, the pressure receiving member, the seal member, the bottom member and the backflow preventing means, which form the pressure receiving chamber and the high pressure chamber, are integrally assembled in advance, and in the process of assembling the lash adjuster, the integral operation is performed. The pressure-receiving chamber and the high-pressure chamber, which are assembled in the above, are arranged in the body. As a result, the number of parts to be assembled in the lash adjuster is reduced to the body, the upper plunger, and the parts integrally assembled with the body, so that the management of the assembled parts is facilitated and the assembling process is simplified.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a lash adjuster of an OHC type valve operating mechanism in an engine as an internal combustion engine will be described below with reference to FIGS.

FIG. 1 shows an OHC type valve operating mechanism A of this embodiment.
The cam 1 fixedly supported by the cam shaft is in contact with the swing arm 2, one end of the swing arm 2 is in contact with the intake / exhaust valve 3, and the other end is in contact with the operating end 4a of the lash adjuster 4. To be done. Further, the intake / exhaust valve 3 is provided with a valve spring 5, whereby the intake / exhaust valve 3 is provided.
Are urged toward the closing direction of the intake / exhaust port 8 formed in the cylinder head 6.

By the rotational driving of the cam 1, the contact position of the cam 1 with respect to the swing arm 2 is displaced in the order of the cam nose 1a which is the protruding portion of the cam 1 → the base portion 1b of the cam → the cam nose 1a, and the swing arm 2 accordingly. Swings around the operating end 4a of the lash adjuster 4 as a fulcrum, so that the intake / exhaust valve 3 is opened / closed with respect to the intake / exhaust port 8.

FIG. 2 is an axial cross-sectional view of the lash adjuster 4 attached to the cylinder head 6, and the body 10 having a recess is composed of a tubular portion 10a and a bottom portion 10c. On the side wall of the tubular portion 10a of the body 10, an oil guide port 10b is formed as a high pressure medium supply unit for introducing lubricating oil as a high pressure medium. Although the body 10 is formed separately from the cylinder head in this embodiment, a recess may be formed in the cylinder head so that the cylinder head itself also serves as the body 10. Tubular part 1
A plunger 11 is axially slidably fitted to the shaft 0a, and the plunger 11 has a cylindrical upper plunger 11 whose operating end 4a abuts on the swing arm 2.
0, and a lower cylindrical plunger 111 joined to the free end of the upper plunger 110 and fitted into the body 10. The upper plunger 110 has a hollow reservoir chamber 13 formed therein, and has a side wall as a high-pressure medium supply unit for introducing lubricating oil as a high-pressure medium into the plunger 11 through a communication with the oil guide port 10b. Oil port 11
a is formed.

The lower plunger 111 has a tubular shape, and the lower plunger 111 is placed at a predetermined position inside the tubular shape.
Inner wall 1 which is divided into two spaces and has a communication passage 14
5 is provided. At the opening end 111a of the lower plunger 111 on the side of joining with the upper plunger 110,
A pressure receiving member 12 made of an elastic material such as a rubber member is attached in an airtight manner to the outer periphery of the pressure receiving member 12 on the inner periphery of the vicinity of the opening end 111a. A pressure receiving chamber 16 is closed between the pressure receiving member 12 and the inner wall 15. The pressure receiving member 12 airtightly divides the pressure receiving chamber 16 and the reservoir chamber 13.

The body 10 of the lower plunger 111
Between the bottom end 10c side opening end 111b and the bottom surface member 17 provided on the top surface of the bottom part 10c of the body 10, a cylindrical elastic body 18 as a sealing member has its upper and lower ends at the opening end 111b and the bottom surface member. It is attached to 17 in a sealed state by adhesion or pressure bonding. The space between the middle wall 15 and the bottom member 17 is a high pressure chamber 19, and the high pressure chamber 19 is
The lower half of the lower plunger 111 on the bottom 10c side and the inner wall 1
5, the tubular elastic body 18, and the bottom member 17 are airtightly defined. The bottom member 17 is not always necessary, and the bottom portion 10c of the body 10 can be used as the bottom surface of the high pressure chamber. In that case,
The lower end of the tubular elastic body 18 is directly attached to the upper surface of the bottom portion 10c of the body 10.

Both the pressure receiving chamber 16 and the high pressure chamber 19 have an inner wall 1
5 is a sealed space formed by the pressure receiving member 12, the cylindrical elastic body 18, and the bottom surface member 17 except that they are communicated by the communication passage 14. Is enclosed. Inside the high-pressure chamber 19, a check ball 21 as a backflow preventing means B for opening and closing the communication passage 14, a biasing spring 20, a retainer 22, and a plunger spring 23 are provided. The check ball 21 is biased to the closed position of the communication passage 14 by the biasing spring 20, and both are held from below by the retainer 22. The plunger spring 23 connects the retainer 22 to the inner wall 15
And the lower plunger 111 is biased toward the upper plunger 110 side.

The lower plunger 111 forming the pressure receiving chamber 16 and the high pressure chamber 19, the pressure receiving member 12, the bottom member 17, the cylindrical elastic body 18, and the backflow preventing means B are previously assembled integrally, and the lash adjuster 4 is installed. It is fitted and arranged in the body 10.

The valve mechanism of this embodiment operates as follows.

When the cam nose 1a of the cam 1 is in contact with the swing arm 2 and the engine is stopped for a long time, the valve spring 5 is compressed and the intake / exhaust valve 3 is connected to the intake / exhaust port as shown in FIG. 8 is the position to open. At this time, the reaction force of the valve spring 5 is applied to the swing arm 2, and the rotation fulcrum of the swing arm 2 moves from the operating end 4a of the lash adjuster 4 to the contact point with the cam nose 1a, and the lash adjuster 4 as a whole has a shaft. The pressing force in the direction is always applied. Therefore, when this stopped state continues for a long time, the hydraulic oil in the high pressure chamber 19 gradually leaks into the pressure receiving chamber 16 through the communication passage 14 from the gap of the check ball 21, the lower plunger 111 descends, and the volume of the high pressure chamber 19 increases. Is the minimum state.

When the engine is subsequently started, the base portion 1b of the cam 1 reaches the contact position of the swing arm 2 as shown in FIG. 3, and the valve spring 5 pushes up the intake / exhaust valve 3 together with the swing arm 2 to absorb the intake air. The exhaust port 8 is closed. On the other hand, in the lash adjuster 4, since the pushing force in the axial direction is released, the lower plunger 111 is pushed up due to the restoring force of the plunger spring 23, the volume of the high pressure chamber 19 increases, and the inside of the high pressure chamber 19 becomes the pressure receiving chamber. Negative pressure is applied to 16. As a result, the check ball 21 opens the communication passage 14 against the urging force of the urging spring 20, and the hydraulic oil in the pressure receiving chamber 16 is sucked into the high pressure chamber 19.
At the same time, when high-pressure lubricating oil is introduced into the reservoir chamber 13 via the oil guide ports 10b and 11a formed in the body 10 and the upper plunger 110, the pressure receiving member 12 is moved to the two-dot chain line in FIG. To the pressure receiving chamber 16 by the lubricating oil pressure
Bulge to the side. As a result, the pressure in the pressure receiving chamber 16 rises, and when the pressure receiving chamber 16 becomes higher than the high pressure chamber 19, the check ball 21 is pressed, the communication passage 14 is opened, and the working oil is transferred from the pressure receiving chamber 16 to the high pressure chamber 19. Flow into.

The high pressure chamber 19 includes a plunger spring 23.
Of the lash adjuster 4 is pushed up by the restoring force of the rush adjuster 4 and the hydraulic oil inflowing, so that the plunger 11 including the lower plunger 111 is pushed up.
Moves up following the swing arm 2. At this time, the tubular elastic body 18 also expands as the high-pressure chamber 19 expands.

This embodiment has the following effects.

(1) Since the high pressure chamber 19 is sealed together with the pressure receiving chamber 16 during the operation of the lash adjuster 4, the working oil mixed with air from the outside flows into the high pressure chamber 19 when the engine is started. There is nothing to do. For this reason, the inside of the high-pressure chamber 19 does not become a so-called air damper state, and unlike the conventional case, the operation becomes unstable and a valve clearance is not generated.

(2) In this embodiment, lubricating oil is introduced into the reservoir chamber 13 at the same time when the engine is started,
The pressure receiving member 12 is displaced toward the pressure receiving chamber 16 by the lubricating oil pressure, whereby the pressure inside the pressure receiving chamber 16 rises and the pressure receiving chamber 1
The hydraulic oil in 6 positively flows into the high pressure chamber 19. According to this structure, the plunger is moved only by the balance between the force applied from the swing arm to the operating end of the lash adjuster and the spring force provided in the high pressure chamber (for example, see Japanese Utility Model Laid-Open No. 63-154808). In comparison with the above, by making the pressure in the high-pressure chamber high, it is possible to increase the moving speed of the plunger by the amount of pushing up the plunger.

(3) Even when the pressure in the high pressure chamber 19 becomes higher than that in the pressure receiving chamber 16, the high pressure chamber 19 has its periphery sealed by the cylindrical elastic body 18, and the hydraulic oil is supplied to the body 10. And the lower plunger 111 does not leak from the gap. As a result, the hydraulic oil flows out of the high pressure chamber 19 only through the communication passage 14, so that the high pressure chamber 19
It is possible to prevent a rapid decrease in the internal pressure.

(4) The pressure receiving chamber 16 and the high pressure chamber 19 are integrally assembled in advance, and are fitted and disposed in the body 10, so that the lash adjuster 4 is assembled in the assembly process. Since the number of parts is reduced to the body 10, the upper plunger 110 and the parts integrally assembled, the management of the assembled parts is facilitated and the assembling process is simplified.

The above embodiment can be modified and implemented as follows.

In the above embodiment, the pressure receiving chamber 1
6 and the members forming the high-pressure chamber 19 are integrally assembled in advance prior to the assembling of the lash adjuster 4, but when the lash adjuster 4 is assembled, the pressure receiving chamber is provided in the body of the lash adjuster 4. 16 and each member forming the high pressure chamber 19 may be sequentially assembled.

In the above embodiment, the plunger 1
Although the reservoir chamber 13 and the pressure receiving chamber 16 are provided inside 1, the arrangement of both chambers is not limited to this. For example, the present invention may be applied to a lash adjuster disclosed in FIG. 3 of JP-A-63-154808, and a reservoir chamber and a pressure receiving chamber may be provided between the outer circumference of the plunger and the body.

In the above embodiment, in order to seal the high pressure chamber 19, the cylindrical elastic body 18 as the seal member is used between the lower plunger 111 and the bottom member 17.
The shape and installation position of the seal member are not limited to this. For example, as shown in FIG. 4, an O-ring 28 made of rubber or the like is used to lower the lower plunger 111 and the body 10.
It is also possible to adopt a configuration in which a space between the space and the space is sealed.

In the above embodiment, the cylindrical elastic body 1
However, it is also possible to adopt a configuration in which a flexible closing member such as the tubular elastic body 18 is not provided. For example,
The hydraulic oil leaking from the high-pressure chamber 19 is circulated to the high-pressure chamber through the pressure-receiving chamber 16 so that the total amount of oil in the pressure-receiving chamber 16 and the high-pressure chamber 19 is substantially constant. It is also possible to adopt such a configuration.

In the above embodiment, the plunger spring 23 of the plunger 11 is provided in the high pressure chamber 19, and the plunger spring 23 and the working oil pressure in the high pressure chamber 19 are combined to provide the plunger 11 of the lash adjuster 4. However, the plunger spring 23 may not be provided, and only the working hydraulic pressure may be used for the extension.

In the above embodiment, the present invention is applied to the swing arm type in the OHC type valve operating mechanism, but the present invention is not limited to this and can be similarly applied to the OHV type valve operating mechanism. Furthermore, the present invention can be implemented in the same manner as in the direct type of the OHC type and the type with a built-in rocker arm as long as the high-pressure medium supply unit can be provided.

In the above embodiment, the reservoir chamber 1
3. Lubricating oil is introduced as a high pressure medium into 3, but specifically, if it is a high pressure medium capable of applying pressure to the pressure receiving member 12, it should be composed of, for example, high pressure gas or high pressure liquid other than lubricating oil. You can

In the above embodiment, the working oil is sealed in the high pressure chamber 19, but the working fluid is not limited to this. If the working fluid has a small volume change even when pressure is applied, it can be composed of water, for example.

[0041]

As an effect of the present invention, since the high pressure chamber is configured as a pressure space sealed together with the pressure receiving chamber,
The hydraulic oil mixed with air does not flow into the high pressure chamber from the outside, and the high pressure chamber can be maintained as a stable pressure chamber. As a result, a valve lash adjuster is realized in which the operation of the lash adjuster is stable and the valve clearance is properly absorbed.

[Brief description of drawings]

FIG. 1 is a sectional view of a valve mechanism of the present invention when an intake / exhaust valve is opened.

FIG. 2 is a sectional view of the lash adjuster of the present invention.

FIG. 3 is a cross-sectional view of the valve mechanism of the present invention when the intake / exhaust valve is closed.

FIG. 4 is a partial cross-sectional view of a lash adjuster using an O-ring as a seal member of the present invention.

FIG. 5 is an explanatory diagram of a prior art valve operating mechanism.

[Explanation of symbols]

1 cam 2 swing arm 3 intake / exhaust valve 4 lash adjuster 10 body 10a tubular part 10b, 11a Oil guide port as high pressure medium supply unit 10c bottom of body 11 Plunger 12 Pressure receiving member 13 Reservoir chamber 14 passages 16 Pressure receiving chamber 18 Cylindrical elastic body as seal member 19 High pressure chamber 20 bias spring 21 check ball 28 O-ring as a sealing member 110 upper plunger 111 Lower plunger 111a, 111b Open end of lower plunger A valve mechanism B Backflow prevention means.

Claims (3)

[Claims] 1. A high pressure chamber that expands or contracts by increasing or decreasing the internal volume by inflowing a working fluid from a communication passage provided with a backflow prevention means, and an internal combustion engine by increasing and expanding the volume of the high pressure chamber. A rush adjuster for a valve mechanism, comprising a plunger urged in a direction to reduce the valve clearance in the valve mechanism of 1 above, and a body having a recess for slidably accommodating the plunger. And a pressure receiving chamber capable of communicating with the high pressure chamber via the communication passage. The reservoir chamber and the pressure receiving chamber are provided with the high pressure medium in the reservoir chamber by the pressure of the high pressure medium. The pressure receiving chamber is partitioned by an expandable pressure receiving member, and the high pressure chamber and the pressure receiving chamber are sealed except that they communicate with each other through the communication passage, and a working fluid is sealed inside. A lash adjuster for valve trains that is characterized by 2. The plunger is disposed in a recess of the body, the high-pressure chamber is formed between the bottom of the body and the plunger, and the high-pressure chamber is disposed around the high-pressure chamber and has upper and lower ends of the plunger. The lash adjuster for a valve operating mechanism according to claim 1, further comprising an expandable seal member that is connected to the bottom surface of the high pressure chamber. 3. The plunger is composed of an upper plunger and a cylindrical lower plunger, and in the cylindrical interior of the lower plunger, a pressure receiving chamber is provided on the upper plunger side by an inner wall having the communication passage, and a bottom side is provided. A high-pressure chamber is formed in the compartment, an opening end of the lower plunger on the upper plunger side is closed by the pressure receiving member, and a bottom member forming a bottom surface of the high-pressure chamber and the lower plunger at the opening end on the bottom side. The seal member for connecting the above is provided, and the lower plunger, the pressure receiving member, the seal member, the bottom member, and the backflow preventing means are integrally assembled and configured. The lash adjuster for the valve mechanism described.