JP2021124053A - Lash adjuster - Google Patents

Abstract

To provide a lash adjuster which can promptly eliminate pump-up.SOLUTION: A lash adjuster 10 comprises: a cylindrical body 11; a plunger 12 having a bottom part 18 and a peripheral wall part 19, slidably arranged in the body 11, forming a high-pressure chamber 27 between the body 11 and itself, forming a low-pressure chamber 22 therein, also forming a valve hole 26 for making the high-pressure chamber 27 and the low-pressure chamber 22 communicate with each other at the bottom part 18, and having a leak passage 41 from which a working fluid charged in the high-pressure chamber 27 leaks, and which is defined between an external peripheral side of the peripheral wall part 19 and an internal peripheral side of the body 11; and a valve body 28 arranged in the high-pressure chamber 27, and capable of blocking the valve hole 26 from the high-pressure chamber 27 side. In the lash adjuster 10, a flow-out part 42 is formed in which the plunger 12 protrudes to the body 11 while exceeding a normal range, and which makes the working fluid in the high-pressure chamber 27 flow out while exceeding a circulation quantity of the working fluid which circulates in the leak passage 41 in a state that the valve body 28 blocks the valve hole 26.SELECTED DRAWING: Figure 2

Description

The present invention relates to a lash adjuster.

As a hydraulic lash adjuster used in a valve gear of an internal combustion engine, the one described in Patent Document 1 is known. This has a bottomed tubular body fixed to a cylinder head and a plunger that is housed in the body so as to be movable up and down, and supports a rocker arm at the upper end of the plunger. The inside of the plunger is a low pressure chamber, the lower part of the body is a high pressure chamber partitioned by the bottom wall of the plunger, and a valve hole is opened in the bottom wall of the plunger. The hydraulic oil supplied from the oil supply passage of the cylinder head is stored in the low-pressure chamber through the communication hole of the peripheral wall of the body and the communication hole of the peripheral wall of the plunger, and the hydraulic oil is also filled in the high-pressure chamber through the valve hole. .. Further, in the high pressure chamber, a spherical valve body capable of closing the valve hole and a spring for urging the plunger upward are housed.

In the lash adjuster, when the pressing force applied from the rocker arm side becomes weaker than the urging force of the spring, the plunger is pushed up and extended by the action of the spring to adjust the valve clearance. At this time, the hydraulic oil in the low-pressure chamber flows into the high-pressure chamber through the valve hole while pushing down the valve body in the high-pressure chamber. As a result, the high-pressure chamber is maintained in a state where the inside is filled with hydraulic oil. On the other hand, in the lash adjuster, when the pressing force applied to the plunger becomes stronger than the urging force of the spring, the valve body urged in the valve closing direction closes the valve hole, so that the high pressure chamber is opened. Since it is in a sealed state, the descent of the plunger is restricted. In this way, the lash adjuster can stably support the rocker arm by making the body and the plunger rigid due to the increase in pressure in the high pressure chamber.

JP-A-2009-47127

For example, the lash adjuster may experience a phenomenon called pump-up, which is excessively extended. In this case, early elimination is required, but once the lash adjuster is extended, a pressing force stronger than the urging force of the spring is applied from the rocker arm side, and in this state the valve hole is opened and the hydraulic oil in the high pressure chamber is low pressure. Unless the hydraulic oil in the high-pressure chamber flows out to the outside, such as outflow to the chamber or the hydraulic oil in the high-pressure chamber gradually flows out from the gap between the inner peripheral surface of the body and the outer peripheral surface of the plunger, it cannot shrink. ..

An object of the present invention is to provide a rusher adjuster capable of promptly eliminating pump-up.

The lash adjuster according to the present invention has a tubular body, a bottom portion and a peripheral wall portion, and is slidably arranged in the body to form a high-pressure chamber between the body and a low-pressure chamber inside. A valve hole for communicating the high pressure chamber and the low pressure chamber is formed in the bottom portion of the hydraulic oil, and the hydraulic oil filled in the high pressure chamber is formed between the outer peripheral side of the peripheral wall portion and the inner peripheral side of the body. The plunger is provided with a plunger in which a leak passage for leaking is partitioned, and a valve body arranged in the high-pressure chamber and capable of closing the valve hole from the high-pressure chamber side, and the plunger slides with respect to the body. A lash adjuster that expands and contracts by the operation, and the amount of hydraulic oil flowing through the leak passage in a state where the plunger protrudes beyond the normal range with respect to the body and the valve body closes the valve hole. It is characterized in that an outflow portion is formed to allow the hydraulic oil in the high-pressure chamber to flow out beyond the above.

In the lash adjuster of the present invention, an outflow portion is formed. When the plunger protrudes beyond the normal range with respect to the body, the outflow portion causes a flow amount of hydraulic oil exceeding the flow amount of the hydraulic oil flowing through the leak passage to flow out from the high pressure chamber. As a result, the volume of the high-pressure chamber can be quickly reduced. Therefore, the lash adjuster of the present invention can quickly eliminate the pump-up.

It is sectional drawing which shows the whole valve gear including the lash adjuster which concerns on Example 1. FIG. It is sectional drawing of the lash adjuster which concerns on Example 1, and shows the state which a plunger is in a normal range with respect to a body. FIG. 5 is a cross-sectional view of the lash adjuster according to the first embodiment, showing a state in which the plunger is at the upper limit of the normal range with respect to the body. FIG. 5 is a cross-sectional view of the lash adjuster according to the first embodiment, showing a state in which the plunger protrudes beyond the normal range with respect to the body in the extension direction. It is sectional drawing which shows the whole valve gear including the lash adjuster which concerns on Example 2. FIG. It is sectional drawing of the lash adjuster which concerns on Example 2, and shows the state which a plunger is in a normal range with respect to a body. FIG. 6 is a sectional view taken along line VII-VII of FIG. FIG. 5 is a cross-sectional view of the lash adjuster according to the second embodiment, showing a state in which the plunger protrudes beyond the normal range with respect to the body in the extension direction. It is sectional drawing of the lash adjuster which concerns on Example 3. FIG. FIG. 5 is an enlarged cross-sectional view of a main part of the lash adjuster according to the fourth embodiment.

Preferred embodiments of the present invention are shown below.
The outflow portion can be a through hole formed through the peripheral wall of the body. In this case, the outflow portion can be easily formed.

The outflow portion can be a groove formed on the inner peripheral surface of the peripheral wall of the body. In this case, a complete outflow portion can be formed in the lash adjuster. For example, by forming a groove that communicates the high-pressure portion and the low-pressure portion, it is possible to form an outflow portion without performing any processing on a portion such as a cylinder head in which a lash adjuster is incorporated.

The outflow portion includes a through hole formed through the peripheral wall of the body, and a groove formed with one end communicating with the through hole and the other end extending axially on the inner peripheral surface of the peripheral wall of the body. And can be configured to have. In this case, since the robustness to the function of the outflow portion can be improved, the hydraulic oil in the high-pressure chamber can be discharged more quickly and reliably.

The outflow portion can communicate with the high pressure chamber when the plunger protrudes beyond the normal range with respect to the body in the extension direction. In this case, the pump-up can be satisfactorily eliminated.

The outflow portion may be provided with a pressure valve that is opened when the pressure becomes a predetermined value or higher. In this case, the hydraulic oil can be discharged from the outflow portion according to the pressure in the high pressure chamber.

<Example 1>
Example 1 of the present invention will be described with reference to FIGS. 1 to 4. The lash adjuster 10 of the first embodiment is provided in a valve gear of an internal combustion engine (engine) of an automobile.

As shown in FIG. 1, the valve gear includes a valve 80 that opens and closes an intake or exhaust port 91 of the cylinder head 90, and a cam 71 that is provided on a camshaft 70 that rotates in synchronization with the engine and operates the valve 80. , A rocker arm 60 that transmits the movement of the cam 71 to the valve 80 is provided. The lash adjuster 10 is fitted inside the mounting hole 93 of the cylinder head 90, and plays a role of automatically adjusting the valve clearance (clearance between the cam 71 and the rocker arm 60) by flood control.

The valve 80 has a valve stem 81, and the valve stem 81 is slidably inserted into the valve guide 92 of the cylinder head 90. The lower end of the valve 80 is a disk-shaped valve body 82 facing the intake or exhaust port 91. A valve spring 85 is provided around the valve stem 81. The valve 80 is urged by a valve spring 85 in a direction in which the valve body 82 closes the intake or exhaust port 91.

One end of the rocker arm 60 is supported by a support portion 20 described later of the lash adjuster 10, the other end is arranged in contact with the upper end of the valve stem 81, and the rocker arm 60 is arranged upward between one end and the other end. A roller 61 that comes into contact with the installed cam 71 is rotatably provided.

As shown in FIG. 1, the lash adjuster 10 is inserted into the mounting hole 93 provided on the upper surface of the cylinder head 90 with its axis directed in the vertical direction. An oil supply passage 94 of the cylinder head 90 communicates with the inner surface of the mounting hole 93. Further, in the case of this embodiment, a mounting hole circumferential groove 95 is formed on the inner surface of the mounting hole 93. The mounting hole peripheral groove 95 is formed below the oil supply passage 94. The mounting hole circumferential groove 95 is formed over the entire circumference of the inner peripheral surface of the mounting hole 93. One end of the communication passage 96 is opened in the mounting hole peripheral groove 95. The communication passage 96 communicates the space inside the mounting hole peripheral groove 95 with the space outside. In the case of this embodiment, one end of the communication passage 96 is opened in the mounting hole peripheral groove 95, and the other end is opened in the space inside the cylinder head 90.

As shown in FIG. 2, the lash adjuster 10 includes a bottomed cylindrical body 11 and a bottomed cylindrical plunger 12 housed in the body 11 so as to be reciprocally movable (reciprocally slidable) in the vertical direction. I have. The lash adjuster 10 expands when the plunger 12 moves in a direction in which it protrudes with respect to the body 11, and contracts when it moves in the opposite direction. The body 11 includes a disk-shaped bottom wall 13 and a peripheral wall 14 rising from the outer periphery of the bottom wall 13. An outer peripheral groove 15 is provided on the outer peripheral surface of the peripheral wall 14 of the body 11 over the entire circumference. Further, the peripheral wall 14 of the body 11 is provided with a body oil hole 16 penetrating in the radial direction (the wall thickness direction of the peripheral wall 14 of the body 11) from the inner peripheral surface of the outer peripheral peripheral groove 15 to the inner peripheral surface. On the inner peripheral surface of the peripheral wall 14 of the body 11, an inner peripheral groove 17 is provided over the entire circumference corresponding to the height position of the opening on the inner peripheral surface side of the body oil hole 16. A retainer 50 that restricts the plunger 12 from coming out upward is attached to the upper end of the peripheral wall 14.

The plunger 12 is housed in the body 11 with its upper end protruding from the upper end of the body 11. The plunger 12 includes a disk-shaped bottom portion 18 that is one size smaller than the bottom wall 13 of the body 11, and a peripheral wall portion 19 that rises from the outer periphery of the bottom portion 18 and whose upper end portion is narrowed to a substantially hemispherical shape. The upper end of the peripheral wall portion 19 of the plunger 12 is a support portion 20, and one end of the rocker arm 60 is slidably supported on the hemispherical outer peripheral surface of the support portion 20 (see FIG. 1). A top hole 21 is provided at the upper end of the support portion 20 so as to penetrate in the vertical direction. The inside of the plunger 12 is configured as a low pressure chamber 22 partitioned by a bottom portion 18 and a peripheral wall portion 19.

At the upper end of the peripheral wall portion 19 of the plunger 12, an annular band portion 23 is provided so as to project thickly outward over the entire circumference. The outer peripheral surface of the annular band portion 23 can be brought into contact with the inner peripheral surface of the upper end portion of the peripheral wall 14 of the body 11 in a substantially liquid-tight manner (sliding contact is possible) along the vertical direction. On the outer peripheral surface of the peripheral wall portion 19 of the plunger 12, a plunger peripheral groove 24 for partitioning the lower end surface of the annular band portion 23 is provided over the entire circumference.

Further, the peripheral wall portion 19 of the plunger 12 is provided with two plunger oil holes 25 penetrating in the radial direction (the wall thickness direction of the peripheral wall portion 19 of the plunger 12) from the groove inner surface to the inner peripheral surface of the plunger peripheral groove 24. ing. Each plunger oil hole 25 has a perfect circular cross section, and is located at the upper end of the plunger peripheral groove 24 which is located at the same height position in the vertical direction and close to the annular band portion 23 on the peripheral wall portion 19 of the plunger 12. It is arranged with an opening. The plunger oil hole 25 is arranged above the body oil hole 16, and the hole diameter (diameter) of the plunger oil hole 25 is smaller than the hole diameter of the body oil hole 16.

Further, the plunger oil holes 25 are arranged so as to coaxially face both ends of the peripheral wall portion 19 of the plunger 12 in the radial direction. The oil supplied from the oil supply passage 94 of the cylinder head 90 is stored in the low pressure chamber 22 through the outer surface peripheral groove 15, the body oil hole 16, the plunger peripheral groove 24 and the plunger oil hole 25. In this case, even if the body 11 rotates in the mounting hole 93 of the cylinder head 90, oil flows into the body oil hole 16 through the outer peripheral groove 15, and even if the plunger 12 rotates in the body 11, the plunger oil Oil flows into the plunger oil hole 25 through the hole 25.

A circular valve hole 26 is provided in the center of the bottom portion 18 of the plunger 12 in the vertical direction so as to penetrate in the vertical direction. A high-pressure chamber 27 is provided in the lower portion of the body 11 between the lower portion 18 and the bottom portion 18 of the plunger 12. In the high pressure chamber 27, a spherical valve body 28 that can move in the vertical direction to open and close the valve hole 26, a cage 29 that holds the valve body 28, and a valve body 28 housed in the cage 29 are housed in the valve hole 26. From a compression coil spring 31 composed of a compression coil spring urging toward, and a compression coil spring interposed between the outer peripheral edge of the cage 29 and the bottom wall 13 of the body 11 to urge the plunger 12 upward. A second spring 32 is provided. The valve body 28 is always urged by the first spring 31 to close the valve hole 26, and reciprocates so as to open the valve hole 26 by descending against the urging force of the first spring 31 in response to a hydraulic fluctuation. Moving. Then, when the valve hole 26 is opened, the oil in the low pressure chamber 22 flows into the high pressure chamber 27 through the valve hole 26.

A leak passage 41 is partitioned between the outer peripheral side of the peripheral wall portion 19 of the plunger 12 and the inner peripheral side of the body 11. The leak passage 41 leaks the hydraulic oil in the high pressure chamber 27. The leak passage 41 is between the outer peripheral surface of the lower portion of the peripheral wall portion 19 (lower than the plunger peripheral groove 24) and the inner peripheral surface of the lower portion of the peripheral wall 14 of the body 11 in a state where the plunger 12 is inserted into the body 11. It is composed of radial gaps partitioned by. The leak passage 41 extends over the entire circumference of the peripheral wall portion 19 in the circumferential direction and is elongated in the vertical direction, the lower end opens to the high pressure chamber 27, and the upper end opens to the plunger peripheral groove 24. ..

An outflow portion 42 is formed in the lash adjuster 10. When the plunger 12 projects beyond the normal range with respect to the body 11, the outflow portion 42 causes the hydraulic oil in the high pressure chamber 27 to flow out in excess of the flow amount of the hydraulic oil flowing through the leak passage 41. In the case of this embodiment, as shown in FIGS. 2 to 4, the outflow portion 42 is a through hole having a substantially circular cross section formed through the peripheral wall 14 of the body 11. The outflow portion 42 communicates with the mounting hole circumferential groove 95 in a state where the lash adjuster 10 is inserted into the mounting hole 93. The cross-sectional area of the outflow portion 42, which is a through hole, is set to be larger than the cross-sectional area of the entire flow path of the leak passage 41.

In this embodiment, the outflow portion 42 communicates with the high pressure chamber 27 when the plunger 12 projects beyond the normal range with respect to the body 11. This "normal range" is a range in which the lash adjuster 10 functions normally in the slidable range of the plunger 12, and is a range in which the valve 80 can be opened and closed normally. The state shown in FIG. 2 shows a state in which the plunger 12 protrudes from the body 11 within a normal range. In this state, the outflow portion 42 does not communicate with the high pressure chamber 27.

The state shown in FIG. 3 shows a state in which the upper end of the plunger 12 is at the maximum protruding position A in the normal range. The maximum protruding position is a position that is not desired to be further extended by design. For example, if it is extended beyond this position, a problem such as pumping up may occur. "Protruding beyond the normal range" is intended for the plunger to project beyond this maximum protruding position. The lower end of the outflow portion 42 is formed at a height position of the peripheral wall 14 corresponding to the lower end of the plunger 12 in the state of being in the maximum protruding position A. When the plunger 12 protrudes beyond the maximum protrusion position A, the lash adjuster 10 exposes the outflow portion 42 to the high pressure chamber 27 and communicates with the high pressure chamber 27 as shown in FIG. It has been made.

Next, the basic operation of the lash adjuster 10 will be described.
When the camshaft 70 and the cam 71 rotate during normal driving of the internal combustion engine and the rocker arm 60 is pressed downward by the cam 71, the valve 80 is pushed down and the valve 80 is opened. At this time, the bearing portion 20 is pressed against one end of the rocker arm 60. As a result, a force in the direction of sinking into the body 11 acts on the plunger 12. At this time, since the valve hole 26 is closed by the valve body 28, the sinking of the plunger 12 is restricted, but the pressure of the high pressure chamber 27 is increased by receiving the force in the compression direction. Then, the hydraulic oil in the high-pressure chamber 27 flows through the leak passage 41 between the peripheral wall portion 19 of the plunger 12 and the peripheral wall 14 of the body 11, and gradually flows out to the plunger peripheral groove 24 side. As a result, the volume of the high pressure chamber 27 is gradually reduced, the plunger 12 sinks into the body 11 (leakdown), and the total length of the lash adjuster 10 is shortened. Further, the body 11 and the plunger 12 become rigid due to the pressure increase of the high pressure chamber 27, and the rocker arm 60 is stably supported by the lash adjuster 10.

Further, when the cam shaft 70 and the cam 71 rotate, the lift amount by the cam 71 decreases from the state where the cam 71 presses the rocker arm 60 downward, and the downward pressing force on the rocker arm 60 is relaxed. Then, the valve 80 is closed by the repulsive force of the valve spring 85. At this time, a force in the direction of being pushed upward by the valve spring 85 acts on the rocker arm 60. Therefore, the force acting on the support portion 20 in the pushing-down direction is relaxed. Then, since the force in the direction of advancing from the second spring 32 to the rocker arm 60 side is acting on the plunger 12, the plunger 12 is pushed up and the support portion 20 is maintained in contact with one end of the rocker arm 60. do. As a result, the rocker arm 60 is pressed against the cam 71. Further, when the plunger 12 advances to the rocker arm 60 side, the volume of the high pressure chamber 27 is expanded and the pressure of the high pressure chamber 27 is reduced. As a result, a pressure difference is generated between the high pressure chamber 27 and the low pressure chamber 22, the valve body 28 separates from the valve hole 26 to open the valve hole 26, and oil flows from the low pressure chamber 22 to the high pressure chamber 27. As a result, the total length of the lash adjuster 10 is extended.
In this way, the lash adjuster 10 supports the rocker arm 60 at an appropriate position in response to the rotation of the cam 71, so that the clearance between the cam 71 and the rocker arm 60 is adjusted to be substantially zero.

The hydraulic oil that flows out from the high pressure chamber 27 through the leak passage 41 leaks to the outside through the body oil hole 16, the portion that returns to the low pressure chamber 22 through the plunger oil hole 25, and further passes through the top hole 21 from the low pressure chamber 22. The flow is divided into a portion that leaks to the outside and lubricates one end of the rocker arm 60. Further, the low pressure chamber 22 is constantly replenished with oil from the oil supply passage 94 of the cylinder head 90 through the plunger oil hole 25, and the oil is stored up to the lower end position of the plunger oil hole 25.

On the other hand, when the internal combustion engine is rotating at high speed, the valve gear including the rocker arm 60 operates at high speed, so that the valve 80 may open unnecessarily due to the occurrence of surging or the like. At this time, in the lash adjuster 10, the plunger 12 may protrude beyond the normal range. When the plunger 12 protrudes beyond the normal range, hydraulic oil will excessively flow into the high pressure chamber 27. Therefore, the lash adjuster 10 is in a state of being excessively extended, that is, a state of being pumped up. If the plunger 12 is maintained in a protruding state beyond the normal range, the valve 80 may not be completely closed. Therefore, the hydraulic oil in the high pressure chamber 27 is discharged to lower the plunger 12. There is a need.

In this embodiment, the pump-up state is quickly eliminated by forming the outflow portion 42. Specifically, when the plunger 12 protrudes beyond the normal range with respect to the body 11, the outflow portion 42 exceeds the flow amount of the hydraulic oil flowing through the leak passage 41 and causes the hydraulic oil in the high pressure chamber 27 to flow. Let it flow out. As a result, the hydraulic oil is rapidly discharged from the high pressure chamber 27. Therefore, the volume of the high-pressure chamber 27 can be rapidly reduced to allow the plunger 12 to sink, and it is possible to prevent the plunger 12 from being maintained in a pump-up state in which the plunger 12 protrudes beyond the normal range.

The outflow portion 42 is a circular through hole formed by penetrating the peripheral wall 14 of the body 11 in the radial direction. The outflow portion 42 communicates with the high pressure chamber 27 when the plunger 12 projects beyond the normal range with respect to the body 11. Specifically, the lower end of the outflow portion 42 is formed at the height position of the peripheral wall 14 corresponding to the lower end of the plunger 12 when the plunger 12 is at the maximum protrusion position A which is the upper limit position of the normal range (FIG. FIG. 3), the plunger 12 protrudes beyond this position and is exposed to the high pressure chamber 27. In this state, when a pressing force acts on the plunger 12 from the upper rocker arm 60, the plunger 12 is pushed down, and accordingly, the hydraulic oil in the high pressure chamber 27 flows from the outflow portion 42 to the mounting hole peripheral groove 95 and the communication passage 96. leak. As described above, when the plunger 12 protrudes beyond the normal range, the lash adjuster 10 promptly drains the hydraulic oil in the high pressure chamber 27 from the outflow portion 42 and is quickly pushed down to the normal range.

When the plunger 12 is pushed down to the normal range, the plunger 12 closes the opening of the outflow portion 42. As a result, further outflow of hydraulic oil from the outflow portion 42 is prevented. Then, the pressure in the high pressure chamber 27 rises, the body 11 and the plunger 12 become rigid, and the rocker arm 60 is stably supported.

As described above, according to the lash adjuster 10 of the first embodiment, since the outflow portion 42 is formed, the hydraulic oil in the high pressure chamber 27 is discharged from the outflow portion 42. When the plunger 12 projects beyond the normal range with respect to the body 11, the outflow portion 42 causes the hydraulic oil in the flow amount exceeding the flow amount of the hydraulic oil flowing in the leak passage 41 to flow out from the high pressure chamber. As a result, the lash adjuster 10 can quickly reduce the volume of the high pressure chamber 27. Therefore, the lash adjuster 10 can quickly eliminate the pump-up.

The outflow portion 42 is a through hole formed through the peripheral wall 14 of the body 11. Therefore, the outflow portion can be easily formed.

The outflow portion 42 communicates with the high pressure chamber 27 when the plunger 12 protrudes beyond the normal range with respect to the body 11 in the extension direction of the lash adjuster 10. Therefore, the lash adjuster 10 can satisfactorily eliminate the pump-up.

<Example 2>
5 to 8 show Example 2 of the present invention. Example 2 is different from Example 1 in that the outflow portion is formed and the like, but is the same as that of Example 1 in other respects. Therefore, in the following description, the same or corresponding structures as those in the first embodiment are designated by the same reference numerals, and the description overlapping with the first embodiment will be omitted.

As shown in FIGS. 5 to 8, the lash adjuster 210 of the second embodiment forms an outflow portion 242. Similar to the first embodiment, the outflow section 242 causes the hydraulic oil in the high pressure chamber 27 to flow out in excess of the flow amount of the hydraulic oil flowing through the leak passage 41. In the case of this embodiment, the outflow portion 242 is a groove formed so as to extend in the axial direction on the inner peripheral surface of the peripheral wall 14 of the body 11. The outflow portion 242 is a groove having a square cross section formed so as to extend linearly substantially parallel to the central axis of the lash adjuster 10. The cross-sectional area of the outflow portion 242 is set to be larger than the cross-sectional area of the entire leak passage 41.

The upper end of the outflow portion 242 is formed so as to extend to the inner peripheral groove 17 on the inner peripheral surface of the peripheral wall 14 of the body 11. That is, the upper end of the outflow portion 242 communicates with the low pressure chamber 22 via the inner surface peripheral groove 17. Therefore, the outflow portion 242 communicates the high pressure chamber 27 with the low pressure chamber 22. In this way, the outflow portion 242 communicates the high-pressure chamber 27 with the low-pressure chamber 22 in the lash adjuster 210. The passage 96 does not need to be formed.

The lower end of the outflow portion 242 is formed so as to extend to a predetermined position. This position corresponds to the lower end of the plunger 12 when the plunger 12 is at the upper limit of the normal range. Therefore, the outflow portion 242 is exposed to the high pressure chamber 27 when the plunger 12 protrudes beyond the normal range with respect to the body 11. As described above, the outflow portion 242 of the second embodiment also communicates with the high pressure chamber 27 when the plunger 12 protrudes beyond the normal range with respect to the body 11, as in the first embodiment.

The lash adjuster 210 of the second embodiment also has the same effect as that of the first embodiment. Further, the outflow portion 242 is a groove formed so as to extend in the axial direction on the inner peripheral surface of the peripheral wall 14 of the body 11. Therefore, a complete outflow portion can be formed in the lash adjuster. That is, since the outflow portion 242 communicates the high pressure chamber 27 and the low pressure chamber 22, it is not necessary to perform any processing on the cylinder head 90 side. Thereby, for example, the effect of the present invention can be easily enjoyed by using the existing lash adjuster in place of the existing lash adjuster.

<Example 3>
FIG. 9 shows Example 3 of the present invention. Example 3 is different from each of the above-mentioned Examples in terms of the formation form of the outflow portion and the like. In addition, the same or corresponding structures as those in each of the above embodiments are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 9, the lash adjuster 310 of Example 3 forms an outflow portion 342. The outflow portion 342 is a combination of the outflow portion 42 of Example 1 and the outflow portion 242 of Example 2. That is, the outflow portion 342 communicates with the outflow portion 42, which is a through hole formed through the peripheral wall 14 of the body 11, and one end communicates with the outflow portion 42, and the other end is on the inner peripheral surface of the peripheral wall 14 of the body 11. It is configured to have an outflow portion 242, which is a groove formed so as to extend in the axial direction.

Such a lash adjuster 310 of Example 3 also has the same effect as that of Example 1. Further, since the lash adjuster 310 can improve the robustness to the function of the outflow portion, the hydraulic oil in the high-pressure chamber can be discharged more reliably and quickly.

<Example 4>
FIG. 10 shows Example 4 of the present invention. Example 4 is different from each of the above-described examples in terms of the formation form of the outflow portion and the like. In addition, the same or corresponding structures as those in each of the above embodiments are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 10, the lash adjuster 410 of Example 4 forms an outflow portion 442. The outflow portion 442 is a through hole formed through the peripheral wall 14 of the body 11 as in the first embodiment, but the opening position is a position where the plunger 12 communicates with the high pressure chamber 27 in a normal range. Is. Further, the outflow portion 442 is provided with a pressure valve 443 that is opened when the pressure becomes a predetermined value or higher. That is, the outflow portion 442 of the fourth embodiment communicates with the high pressure chamber 27 when the pressure of the high pressure chamber 27 becomes equal to or higher than a predetermined value.

For example, when the plunger 12 protrudes beyond the normal range, the magnitude of the pressing force from the rocker arm 60 side becomes larger than when the plunger 12 is in the normal range. This is because when the plunger 12 protrudes beyond the normal range, the amount of compression of the valve spring 85 becomes larger than when the plunger 12 is in the normal range. The pressure valve 443 can be opened, for example, when the plunger 12 receives such an excessive pressing force and the pressure in the high pressure chamber 27 rises. In this case, the "pressure above a predetermined value" is a pressure based on the magnitude of the pressing force received from the rocker arm 60 side when the plunger 12 protrudes beyond the normal range.

The lash adjuster 410 of the fourth embodiment can discharge the hydraulic oil from the outflow portion according to the pressure in the high pressure chamber.

<Other Examples>
Hereinafter, other embodiments will be briefly described.
(1) In the first embodiment, the outflow portion formed as a through hole penetrating the peripheral wall of the body communicates with the external space through the mounting hole peripheral groove and the communication passage, and the outflow in this case is illustrated. The form of communication between the part and the external space is not particularly limited. When the outflow portion is a through hole, as a form of communication between the outflow portion and the external space, for example, a form in which a groove-shaped communication passage is formed on the outer peripheral surface of the body can be mentioned. This groove may have a form in which the lower end communicates with the outflow portion and the upper end communicates with an external space such as a body peripheral groove or an upper end opening of a mounting hole. Further, for example, the outflow path and the external space can be used by utilizing the gap between the mounting hole for mounting the lash adjuster and the body formed in the cylinder head, the hole for venting air when mounting the lash adjuster in the mounting hole, and the like. May communicate with.
(2) In Examples 1 and 2 above, a mode in which only one outflow portion is formed has been illustrated, but a plurality of outflow portions may be provided.
(3) In the third embodiment, a form in which two outflow portions having different forms such as a through hole and a groove are combined has been illustrated, but a form in which three or more outflow portions of at least two types are combined may be used.
(4) In the above-mentioned Examples 2 and 3, the form in which the outflow portion has a groove is illustrated, but the form of the groove in this case is not limited to the form of each of the above-mentioned Examples. The groove may be formed in a spiral shape on the inner peripheral surface of the peripheral wall of the body, for example.
(5) In the fourth embodiment, the outflow portion communicates with the high-pressure chamber even when the plunger is in the normal range. However, as in the first to third embodiments, the plunger has a body in the extension direction. When it protrudes beyond the normal range, it may communicate with the high-pressure chamber.

10, 210, 310, 410 ... Rush adjuster 11 ... Body 12 ... Plunger 14 ... Peripheral wall 18 ... Bottom 19 ... Peripheral wall 22 ... Low pressure chamber 26 ... Valve hole 27 ... High pressure chamber 28 ... Valve body 41 ... Leak passage 42,242 342, 442 ... Outflow part 443 ... Pressure valve

Claims (6)

With a tubular body
It has a bottom portion and a peripheral wall portion and is slidably arranged in the body, forms a high pressure chamber between the body and a low pressure chamber inside, and forms the high pressure chamber and the low pressure chamber in the bottom. A plunger is formed with a valve hole communicating with the above, and a leak passage through which the hydraulic oil filled in the high-pressure chamber leaks is partitioned between the outer peripheral side of the peripheral wall portion and the inner peripheral side of the body.
A valve body arranged in the high-pressure chamber and capable of closing the valve hole from the high-pressure chamber side,
A lash adjuster that expands and contracts when the plunger slides with respect to the body.
When the plunger protrudes beyond the normal range with respect to the body and the valve body closes the valve hole, the hydraulic oil in the high-pressure chamber flows out in excess of the flow amount of the hydraulic oil flowing through the leak passage. A lash adjuster characterized in that an outflow portion is formed. The lash adjuster according to claim 1, wherein the outflow portion is a through hole formed through the peripheral wall of the body. The lash adjuster according to claim 1, wherein the outflow portion is a groove formed on the inner peripheral surface of the peripheral wall of the body. The outflow portion includes a through hole formed through the peripheral wall of the body, and a groove formed with one end communicating with the through hole and the other end extending axially to the inner peripheral surface of the peripheral wall of the body. The lash adjuster according to claim 1, which is configured to have and. The lash adjuster according to any one of claims 1 to 4, wherein the outflow portion communicates with the high-pressure chamber when the plunger projects beyond the normal range with respect to the body. The lash adjuster according to any one of claims 1 to 5, wherein the outflow portion is provided with a pressure valve that is opened when a pressure equal to or higher than a predetermined value is reached.

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