JP2014070559A - Lash adjuster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress abnormal sound generated by oil shortage of a high pressure chamber even in a case where a lash adjuster is downsized.SOLUTION: A storage wall 13 is formed in the upper end part of a body 10 of a lash adjuster 1, and a storage section 15 for storing oil is formed by the inner peripheral surface of the storage wall 13 and the outer peripheral surface of a plunger 20 opposite to the inner peripheral surface. An introduction hole 22 is formed on a peripheral surface 21 of the plunger 20. An introduction groove 29 for introducing the oil in the storage section 15 to the introduction hole 22 by a self-weight is formed on the outer peripheral surface of the plunger 20.

Description

  The present invention relates to a hydraulic lash adjuster provided in an internal combustion engine.

  For example, a lash adjuster described in Patent Document 1 is well known. This lash adjuster includes a bottomed cylindrical body attached to a cylinder head, and a plunger that can be displaced in the body along the axial direction of the body. An inner space of the plunger is defined as a low pressure chamber by the bottom of the plunger, and a space between the inner wall of the body and the bottom of the plunger is defined as a high pressure chamber. In addition, a valve hole is formed in the bottom, and oil from the low pressure chamber is supplied to the high pressure chamber when the check valve provided in the high pressure chamber is opened.

  According to such a lash adjuster, when the plunger advances toward the rocker arm as the rocker arm swings, the volume of the high pressure chamber is expanded and the pressure of the high pressure chamber is reduced. Thereby, the force which urges | biases the valve body of a non-return valve to a valve closing direction falls, and this non-return valve opens. As a result, the oil in the low pressure chamber flows into the high pressure chamber, the pressure in the high pressure chamber increases, and the valve body is displaced again in the valve closing direction, whereby the valve hole is closed again by the valve body.

  On the other hand, when the plunger moves back into the body as the rocker arm swings, the valve hole is closed by the valve body of the check valve, so that oil does not flow from the high pressure chamber into the low pressure chamber. For this reason, the backward movement of the plunger into the body is restricted by the pressure of the oil in the high pressure chamber. Thus, the lash adjuster functions as a fulcrum of the rocker arm by resisting the load acting on the plunger from the rocker arm.

  By the way, there is a lash adjuster in which when the engine operation is stopped, the plunger is retracted into the body by being continuously pushed by the rocker arm due to the rotational phase of the cam, that is, sinking. In such a lash adjuster, the high pressure chamber continues to be compressed by the plunger, so that oil in the high pressure chamber leaks out of the lash adjuster through the space between the inner peripheral surface of the body and the outer peripheral surface of the plunger. As a result, there is a problem in that abnormal noise is generated as a result of the oil in the high-pressure chamber becoming insufficient and the plunger colliding with the inner wall of the body after the engine operation is started.

  In the conventional lash adjuster, the volume of the low pressure chamber is increased to some extent, so that when the check valve is opened, the oil in the low pressure chamber is supplied to the high pressure chamber, so that the shortage of oil in the high pressure chamber is accelerated. It has been resolved.

JP 2009-281170 A

  By the way, in order to reduce the size of the lash adjuster in order to reduce the size and weight of the internal combustion engine, it is necessary to reduce the volume of the low pressure chamber. However, as described above, if the volume of the low-pressure chamber is reduced, the amount of oil that can be stored in the low-pressure chamber decreases. Therefore, until the oil is supplied to the low-pressure chamber after the engine operation is started, The oil shortage cannot be resolved. As a result, abnormal noise is generated due to insufficient oil in the high pressure chamber.

  An object of the present invention is to provide a lash adjuster that can suppress the generation of abnormal noise due to insufficient oil in the high-pressure chamber even when the lash adjuster is downsized.

  In order to achieve the above object, a lash adjuster according to the present invention comprises a cylindrical body and a plunger that can be displaced in the body along the axial direction of the body, and a valve hole is formed at the bottom of the plunger. The space between the inner wall of the body and the bottom of the plunger is provided with a valve body capable of closing the valve hole and an urging member for urging the valve body in the direction in which the valve hole is closed. The space between the inner wall of the body and the bottom of the plunger is a high pressure chamber, and the valve clearance of the engine valve is adjusted through the movement of the plunger from the opening of the body. In addition, a reservoir for storing oil is formed by the inner peripheral surface of the end of the body constituting the opening and the outer peripheral surface of the plunger facing the end, and the plunger and the low pressure chamber communicate with each other. An introduction part for introducing the oil in the storage part into the low pressure chamber by its own weight is formed.

  According to this configuration, the oil leaked from the high pressure chamber through the space between the inner peripheral surface of the body and the outer peripheral surface of the plunger is between the inner peripheral surface of the opening end of the body and the outer peripheral surface of the plunger facing the oil. It will be stored in the storage part. Further, the oil scattered from the cam that drives the engine valve and the oil from the cam shower that injects oil to the cam are stored in the storage section. And the oil stored in this way comes to be introduced into the low pressure chamber through the introduction part of the plunger. For this reason, the oil stored in the storage part after the engine is stopped can be supplied to the low pressure chamber, and the amount of oil in the low pressure chamber can be increased. Thereby, it is possible to suppress a shortage of oil in the low pressure chamber after the engine operation is started, and to suppress a shortage of oil in the high pressure chamber by supplying oil from the low pressure chamber to the high pressure chamber. it can. Therefore, even when the lash adjuster is downsized, it is possible to suppress the generation of abnormal noise due to insufficient oil in the high pressure chamber.

  In this case, an introduction hole is formed in the peripheral wall of the plunger, and at least one of the inner peripheral surface of the body and the outer peripheral surface of the plunger is formed with an introduction groove for introducing the oil in the reservoir into the introduction hole by its own weight, It is preferable that the introduction part is constituted by the introduction hole and the introduction groove.

  According to this aspect, the oil stored in the storage portion is introduced into the low pressure chamber through the introduction groove formed in at least one of the inner peripheral surface of the body and the outer peripheral surface of the plunger, and the introduction hole formed in the peripheral wall of the plunger. Become so.

  Further, it is preferable that the body is attached to the mounting hole of the cylinder head, and the end of the body constituting the storage portion protrudes from the end face of the cylinder head.

  According to this aspect, the volume of the storage part can be suitably increased, and a large amount of oil can be stored in the storage part. Accordingly, it is possible to further suppress the shortage of oil in the low pressure chamber after the engine operation is started.

In this case, the aspect that the edge part of the body which comprises the said storage part is extended in the radial direction outer side of the body rather than the internal peripheral surface of the said attachment hole is preferable.
According to this aspect, since the opening of the body becomes large, the oil scattered from the cam and the oil injected from the cam shower can be suitably stored in the storage unit. Accordingly, it is possible to further suppress the shortage of oil in the low pressure chamber after the engine operation is started.

Moreover, the aspect that the edge part of the body which comprises the said storage part is provided over the whole circumferential direction of the body is preferable.
According to this aspect, for example, in a configuration in which the body opens upward in the vertical direction, oil in the reservoir can be suitably prevented from spilling.

Moreover, the aspect that the edge part of the body which comprises the said storage part is partially provided in the circumferential direction of the body is preferable.
For example, in the case of a lash adjuster applied to a V-type internal combustion engine in which the cylinder row is inclined with respect to the vertical direction, the end of the body constituting the reservoir is provided over the entire circumferential direction of the body. In other words, the portion of the end portion of the body that is positioned above the vertical direction does not function to store oil. In this respect, according to the above-described configuration, the end of the body constituting the storage portion is partially provided in the circumferential direction of the body, so that an increase in the weight of the body can be suitably suppressed.

In addition, it is preferable that the inside and outside of the body communicate with each other only at the opening of the body.
According to this aspect, since the inside and outside of the body are communicated only at the opening of the body in which the plunger appears and disappears, for example, a configuration in which a hole for introducing oil into the low pressure chamber is formed in the peripheral wall of the body In contrast, the problem of oil leaking from the low pressure chamber through these holes does not occur. Therefore, the oil from the reservoir can be supplied to the low pressure chamber without waste, and the amount of oil in the low pressure chamber can be suitably increased.

1 is a schematic diagram of a valve mechanism of an internal combustion engine to which a lash adjuster according to an embodiment is applied. The longitudinal cross-sectional view centering on the lash adjuster of the embodiment. FIG. 3 is a cross-sectional view of the lash adjuster taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view of the lash adjuster along line 4-4 in FIG. 2; The longitudinal cross-sectional view centering on the lash adjuster for demonstrating the effect | action of the embodiment. The longitudinal cross-sectional view centering on the lash adjuster of a comparative example. The longitudinal cross-sectional view centering on the lash adjuster which concerns on a modification. The longitudinal cross-sectional view centering on the lash adjuster which concerns on another modification.

Hereinafter, an embodiment of the lash adjuster will be described with reference to FIGS.
As shown in FIG. 1, a retainer 92 is attached to the engine valve 91 of the internal combustion engine 80, and a valve spring 93 is provided between the retainer 92 and the cylinder head 81. The engine valve 91 is always urged in the valve closing direction by the valve spring 93.

  The valve mechanism is a pivot type mechanism that opens and closes the engine valve 91, and includes a camshaft 82 to which rotation of a crankshaft (not shown) of the internal combustion engine 80 is transmitted, and a cam fixed to the camshaft 82. 83 and a roller-type rocker arm 84 that is driven as the cam 83 rotates.

  One end of the rocker arm 84 (left end in the figure) is supported by the base end 91a of the engine valve 91, and the other end (right end in the figure) is provided in the cylinder head 81. It is supported by the tip of a lash adjuster 1 of the type. The rocker arm 84 can swing around a roller 85, and the roller 85 is in contact with the cam 83.

  Therefore, when the roller 85 is pressed by the rotation of the cam 83, the rocker arm 84 swings with the other end as a fulcrum. Thereby, the base end part 91a of the engine valve 91 is pressed, and the engine valve 91 is opened.

Next, the structure of the lash adjuster 1 will be described.
As shown in FIG. 2, the body 10 of the lash adjuster 1 has a bottomed cylindrical shape, and is attached to an attachment hole 81 b that is recessed in the end surface 81 a of the cylinder head 81. A bottomed cylindrical plunger 20 that can be displaced along the axial direction C is provided in the body 10.

  Hereinafter, the axial direction C of the body 10 is simply referred to as the axial direction C. Further, the direction in which the plunger 20 advances toward the rocker arm 84 is referred to as the upper side, and the direction in which the plunger 20 moves backward in the body 10 is referred to as the lower side.

  A storage wall 13 constituting an opening 14 is formed at the upper end of the peripheral wall 11 of the body 10 over the entire circumferential direction of the body 10. The opening 14 is directed upward in the vertical direction. The storage wall 13 extends outward in the radial direction of the body 10 toward the upper side, and protrudes upward from the end surface 81 a of the cylinder head 81. Further, the upper end portion of the storage wall 13 is located on the radially outer side of the body 10 with respect to the inner peripheral surface of the mounting hole 81b. A storage portion 15 for storing oil is formed by the inner peripheral surface of the storage wall 13 and the outer peripheral surface of the plunger 20 facing the storage wall 13.

The peripheral wall 11 of the body 10 is not formed with a hole that communicates the inside and the outside, and the inside and outside of the body 10 are communicated only at the opening 14.
The internal space of the plunger 20 is partitioned as a low pressure chamber 41 by the peripheral wall 21 and the bottom 24. Further, a space between the inner wall of the body 10 and the bottom 24 of the plunger 20 is partitioned as a high pressure chamber 42.

A valve hole 25 for communicating the low pressure chamber 41 and the high pressure chamber 42 is formed in the bottom 24 of the plunger 20.
The high-pressure chamber 42 is provided with a bottomed cylindrical retainer 27. A first spring 31 is provided between the inner bottom surface of the body 10 and a flange 27 a provided at the upper end of the retainer 27. The biasing force of the first spring 31 causes the plunger 20 to move upward via the flange 27 a. Always energized.

  A spherical valve body 26 capable of closing the valve hole 25 is accommodated in the retainer 27. A second spring 32 is provided between the inner bottom surface of the retainer 27 and the valve body 26 to bias the valve body 26 upward, that is, in a direction in which the valve hole 25 is closed. Note that a hole 27b is formed in the retainer 27, and the inside and outside of the retainer 27 communicate with each other.

  As shown in FIG. 2 and FIG. 3, an introduction hole 22 is formed in the peripheral wall 21 of the plunger 20. Is formed.

  As shown in FIGS. 2 and 4, an introduction groove 29 for introducing the oil in the reservoir 15 into the introduction hole 22 by its own weight is formed on the outer peripheral surface of the plunger 20. The introduction hole 22 and the introduction groove 29 constitute an introduction portion according to the present invention.

Next, a basic operation mode of the lash adjuster 1 will be described.
As shown in FIGS. 1 and 2, when the cam crest moves away from the roller 85 as the cam 83 rotates, that is, when the engine valve 91 starts to close, one end of the rocker arm 84 (the right end in FIG. Part) tends to be separated from the tip of the plunger 20. At this time, when the plunger 20 advances toward the rocker arm 84 by the restoring force of the first spring 31, the rocker arm 84 is pressed against the cam 83. Thus, when the rocker arm 84 follows the cam 83, the clearance between the rocker arm 84 and the cam 83 is suppressed, and the valve clearance of the engine valve 91 is adjusted.

  Here, when the plunger 20 advances from the body 10, the volume of the high pressure chamber 42 is expanded and the pressure of the high pressure chamber 42 is reduced. Thereby, the force which urges | biases the valve body 26 in the valve closing direction falls, and the valve body 26 opens. As a result, the oil in the low pressure chamber 41 flows into the high pressure chamber 42, the pressure in the high pressure chamber 42 increases, and the valve body 26 is displaced again in the valve closing direction, whereby the valve hole 25 is closed again by the valve body 26. Is done.

  On the other hand, when the cam crest attempts to push the roller 85 as the cam 83 rotates, that is, when the engine valve 91 starts to open, one end of the rocker arm 84 (the right end in FIG. 1) pushes the tip of the plunger 20. Try to push. As a result, the plunger 20 attempts to retreat into the body 10. However, at this time, since the valve hole 25 is closed by the valve body 26, the oil does not flow from the high pressure chamber 42 into the low pressure chamber 41. For this reason, the backward movement of the plunger 20 into the body 10 is limited by the pressure of the oil in the high pressure chamber 42. In this way, the lash adjuster 1 functions as a fulcrum of the rocker arm 84 by resisting the load acting on the plunger 20 from the rocker arm 84.

Next, the operation of this embodiment will be described.
As shown in FIG. 5, the oil leaking from the high pressure chamber 42 through the space between the inner peripheral surface of the body 10 and the outer peripheral surface of the plunger 20 is the inner peripheral surface of the storage wall 13 of the body 10 and the plunger 20 facing this. It will be stored by the storage part 15 between these outer peripheral surfaces. Further, the oil scattered from the cam 83 that drives the engine valve 91 and the oil from the cam shower that injects oil to the cam 83 are stored in the storage unit 15.

  The oil thus stored is introduced into the low pressure chamber 41 through the introduction groove 29 formed in the outer peripheral surface of the plunger 20 and the introduction hole 22 formed in the peripheral wall of the plunger 20.

  For this reason, the oil stored in the storage part 15 can be supplied to the low pressure chamber 41 after the engine is stopped, and the amount of oil in the low pressure chamber 41 can be increased. Thus, the shortage of oil in the low pressure chamber 41 after the engine operation is started is suppressed, and the oil in the high pressure chamber 42 is insufficient due to the supply of oil from the low pressure chamber 41 to the high pressure chamber 42. It is suppressed.

According to the lash adjuster according to the present embodiment described above, the following effects can be obtained.
(1) The storage wall 13 is formed in the upper end part of the body 10 of the lash adjuster 1, and the storage part 15 which stores oil with the inner peripheral surface of the storage wall 13 and the outer peripheral surface of the plunger 20 facing this. Is formed. An introduction hole 22 is formed in the peripheral wall 21 of the plunger 20. In addition, an introduction groove 29 for introducing the oil in the reservoir 15 into the introduction hole 22 by its own weight is formed on the outer peripheral surface of the plunger 20. According to such a configuration, the oil stored in the storage unit 15 after the engine is stopped can be supplied to the low pressure chamber 41, and the amount of oil in the low pressure chamber 41 can be increased. Thereby, it is possible to suppress the shortage of oil in the low pressure chamber 41 after the engine operation is started, and the oil in the high pressure chamber 42 is insufficient due to the supply of oil from the low pressure chamber 41 to the high pressure chamber 42. Can be suppressed. Therefore, even when the lash adjuster 1 is downsized, it is possible to suppress the generation of abnormal noise due to insufficient oil in the high pressure chamber 42.

  (2) Since the storage wall 13 protrudes from the end surface 81 a of the cylinder head 81, the volume of the storage unit 15 can be increased and a large amount of oil can be stored in the storage unit 15. Therefore, it is possible to suppress a shortage of oil in the low pressure chamber 41 after the engine operation is started.

  (3) The storage wall 13 extends outward in the radial direction of the body 10 from the inner peripheral surface of the mounting hole 81 b of the cylinder head 81. According to such a configuration, since the opening 14 of the body 10 becomes large, the oil scattered from the cam 83 and the oil injected from the cam shower can be suitably stored in the storage unit 15. Therefore, it is possible to suppress a shortage of oil in the low pressure chamber 41 after the engine operation is started.

(4) Since the storage wall 13 is provided over the whole circumferential direction of the body 10, it can suppress suitably that the oil in the storage part 15 spills down.
(5) The inside and outside of the body 10 are communicated only at the opening 14 of the body 10. Therefore, for example, a hole 112 is formed in the peripheral wall 111 of the body 110 as in the lash adjuster 101 of the comparative example shown in FIG. 6, and the oil pumped from the oil pump is passed through the oil passage 172 inside the cylinder head 181 to the hole 112. Unlike the supply configuration, the problem that the oil in the low-pressure chamber 141 leaks through the hole 112 does not occur. Therefore, the oil from the storage wall 13 can be supplied to the low pressure chamber 41 without waste, and the amount of oil in the low pressure chamber 41 can be suitably increased.

The lash adjuster according to the present invention is not limited to the configuration exemplified in the above-described embodiment, and can be implemented as, for example, the following forms appropriately modified.
In the above embodiment, the inside and outside of the body 10 communicate with each other only at the opening 14. However, as in the comparative example of FIG. 6, a hole is further formed in the peripheral wall of the body to be formed inside the cylinder head. Alternatively, oil may be supplied to the hole through the oil passage. Even in this case, the amount of oil in the low-pressure chamber can be increased by supplying the oil stored in the storage part to the low-pressure chamber after the engine is stopped.

  A lash adjuster 201 having a body 210 as shown in FIG. 7 may be employed. That is, a storage wall 213 constituting the opening 214 is formed at the upper end portion of the peripheral wall 211 of the body 210 over the entire circumferential direction of the body 210. The storage wall 213 extends on the end surface 81a of the cylinder head 81 to the outside in the radial direction of the body 210, and bends and extends upward at the outer peripheral side end. A storage portion 215 is formed between the inner peripheral surface of the storage wall 213 and the outer peripheral surface of the plunger 20 facing the storage wall 213.

  As shown in FIG. 8, in the lash adjuster 301 applied to the V-type internal combustion engine, the storage wall 313 of the body 310 may be partially provided in the circumferential direction of the body 310. More specifically, the storage wall 313 may be provided in a portion other than the portion positioned above the plunger 320 in the vertical direction. In this case, an increase in the weight of the body 310 can be suitably suppressed by providing the storage portion 315 only in a portion having a function of storing oil.

  In the above embodiment, the introduction groove 29 is formed on the outer peripheral surface of the plunger 20, but instead of this, or in addition to this, the introduction groove may be formed on the inner peripheral surface of the body.

  In the above embodiment, the introduction hole 22 is formed in the plunger 20 and the introduction groove 29 is formed in the outer peripheral surface of the plunger 20, but the oil in the reservoir can be directly introduced into the low pressure chamber through the introduction hole. In this case, the introduction groove can be omitted.

  DESCRIPTION OF SYMBOLS 1 ... Rush adjuster, 10 ... Body, 11 ... Perimeter wall, 13 ... Reservation wall, 14 ... Opening, 15 ... Storage part, 20 ... Plunger, 21 ... Peripheral wall, 22 ... Introduction hole, 23 ... Recessed part, 24 ... Bottom part, 25 ... Valve hole, 26 ... Valve body, 27 ... Retainer, 27a ... Flange, 27b ... Hole, 29 ... Introduction groove, 31 ... First spring, 32 ... Second spring (biasing member), 41 ... Low pressure chamber, 42 ... High pressure Chamber 71 ... Oil pump 72 ... Supply passage 80 ... Internal combustion engine 81 ... Cylinder head 81a ... End face 81b ... Mounting hole 82 ... Camshaft 83 ... Cam 84 ... Rocker arm 85 ... Roller 91 ... Engine valve, 91a ... proximal end, 92 ... retainer, 93 ... valve spring.

Claims (7)

A cylindrical body, and a plunger that can be displaced in the body along the axial direction of the body,
A valve hole is formed in the bottom of the plunger,
A space between the inner wall of the body and the bottom of the plunger is provided with a valve body that can close the valve hole and a biasing member that biases the valve body in a direction in which the valve hole is closed,
The internal space of the plunger is a low pressure chamber and the space between the inner wall of the body and the bottom of the plunger is a high pressure chamber,
In the lash adjuster that adjusts the valve clearance of the engine valve through the plunger's appearance from the opening of the body,
A reservoir for storing oil is formed by the inner peripheral surface of the end of the body constituting the opening and the outer peripheral surface of the plunger facing the end,
The plunger is formed with an introduction portion for communicating the storage portion and the low pressure chamber and introducing oil in the storage portion into the low pressure chamber by its own weight.
Rush adjuster characterized by that. An introduction hole is formed in the peripheral wall of the plunger,
At least one of the inner peripheral surface of the body and the outer peripheral surface of the plunger is formed with an introduction groove for introducing the oil in the reservoir into the introduction hole by its own weight,
The introduction part is constituted by the introduction hole and the introduction groove.
The lash adjuster according to claim 1. The body is attached to the mounting hole of the cylinder head,
The end of the body constituting the storage part protrudes from the end face of the cylinder head,
The lash adjuster according to claim 1 or 2. The end portion of the body constituting the storage portion extends radially outward of the body from the inner peripheral surface of the mounting hole.
The lash adjuster according to claim 3. The end part of the body constituting the storage part is provided over the entire circumferential direction of the body,
The lash adjuster according to any one of claims 1 to 4. The end of the body constituting the storage part is partially provided in the circumferential direction of the body,
The lash adjuster according to any one of claims 1 to 4. The inside and outside of the body are communicated only at the opening of the body,
The lash adjuster according to any one of claims 1 to 6.