JP2010059797A - Lash adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lash adjuster with a friction coefficient between the pressure side flanks of a male screw and a female screw less likely to decrease even after the lash adjuster is used for a long period of time. <P>SOLUTION: The lash adjuster 1 of a valve gear has a nut member 14 having the female screw 15 in the inner periphery, an adjusting screw 17 having on the outer periphery the male screw 16 engaging with the female screw 15 and a return spring 18 energizing the adjusting screw 17 toward a direction in which it projects from the nut member 14, and when an axial load is applied in a direction in which the adjusting screw 17 is pushed into the nut member 14, receives the axial load by the pressure side flanks 21 of the male screw 16 and the female screw 15. In the lash adjuster, the return spring 18 gives to the adjust screw 17 rotation force in the direction in which it projects from the nut member 14 and axial force in the direction in which it projects from the nut member 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lash adjuster incorporated in an engine valve gear.

  As a valve operating device that operates a valve provided in the intake port or exhaust port of an engine, a valve lifter supported so as to be slidable up and down is pushed down by a cam, and the valve stem is pushed down by the valve lifter (direct valve operating device) ), One end of an arm supported so as to be swingable with the center as a fulcrum, and a valve stem pushed down at the other end of the arm (rocker arm type valve gear), one end Known is a swing arm type valve operating device in which a central portion of an arm supported as a fulcrum is pushed down by a cam and a valve stem is pushed down at the other end of the arm.

  In these valve operating apparatuses, during engine operation, gaps between the constituent members of the valve operating apparatus change due to thermal expansion differences that occur between the constituent members of the valve operating apparatus, and abnormal noise and compression leakage occur due to changes in the gaps. There is a fear. Further, even if the sliding portion of the valve operating device is worn, the gap between the constituent members of the valve operating device changes, and there is a possibility that abnormal noise is generated due to the change in the gap.

  In order to prevent this abnormal noise and compression leakage, generally, a lash adjuster is incorporated in the valve operating device, and the lash adjuster absorbs a change in a gap between components of the valve operating device.

  As such a lash adjuster, in the above swing arm type valve gear, the nut member inserted into the accommodation hole opened on the upper surface of the cylinder head and the female screw formed on the inner periphery of the nut member are screw-engaged. An adjusting screw having a male screw on its outer periphery; and a torsion spring that imparts a rotational force in a direction protruding upward from the nut member to the adjusting screw, and the arm of the valve gear at the protruding end of the adjusting screw from the nut member Is known to be swingable (Patent Documents 1 and 2).

  Further, in the rocker arm type valve gear, the screw member is engaged with a nut member inserted into a receiving hole opened in the lower surface of the arm that swings according to the rotation of the cam, and a female screw formed on the inner periphery of the nut member. An adjusting screw having a male screw on the outer periphery thereof, and a torsion spring for applying a rotational force in a direction protruding downward from the nut member to the adjusting screw, and a valve operating device at a protruding end of the adjusting screw from the nut member Those that press the valve stem are known (Patent Documents 1 and 2).

  In the direct valve operating apparatus, a lifter body that is slidably inserted into a guide hole formed in the cylinder head, a nut member that moves up and down integrally with the lifter body, and an inner periphery of the nut member An adjustment screw having a male screw on its outer periphery that engages with the formed female screw, and a torsion spring that imparts a rotational force in a direction of projecting downward from the nut member to the adjustment screw, from the nut member of the adjustment screw There is known one that presses a valve stem of a valve operating device at the protruding end of the valve (Patent Document 2).

  In these lash adjusters, when an axial load in the direction in which the adjusting screw is pushed into the nut member (hereinafter referred to as the “pushing direction”) is applied due to the rotation of the cam, the pressure side flank of the male screw becomes the pressure side flank of the female screw. The axial position of the adjusting screw is fixed. Strictly speaking, a slight slip occurs between the pressure flank of the male screw and the female screw at this time, and the adjustment screw moves in the pushing direction due to the sliding, but when the cam further rotates and the load in the pushing direction is released. In addition, the adjusting screw moves in the protruding direction while rotating by the force of the torsion spring, and returns to the original position.

  In addition, when the gap between the components of the valve operating device becomes large due to thermal expansion of the valve operating device, the cam is further pushed than the adjustment screw is pushed in when the load in the pushing direction is applied by the cam. The amount of protrusion of the adjusting screw when the load in the pushing direction is released by rotation is increased. As a result, each time the cam rotates, the adjustment screw gradually moves in the protruding direction to absorb the change in the gap between the constituent members of the valve gear.

On the other hand, when the gap between the components of the valve operating device becomes small, the cam rotates further than the amount of pushing of the adjusting screw when the load in the pushing direction is applied by the cam. The protruding amount of the adjusting screw when released is reduced. As a result, each time the cam rotates, the adjustment screw moves by several microns in the push-in direction to absorb the change in the gap between the constituent members of the valve gear.
Japanese Utility Model Publication No. 64-34407 Japanese Patent No. 2607404

  By the way, each of these lash adjusters urges the adjustment screw in the protruding direction by causing a slip between the male side and the female side pressure side flank by the rotational force of the torsion spring. Therefore, both when the adjusting screw moves in the pushing direction and when it moves in the protruding direction, the pressure side flank of the male screw and the female screw remains in contact with each other, making it difficult for lubricating oil to enter between the pressure side flank. The pressure side flank was easy to wear.

  When the pressure side flank of the male screw and the female screw is worn, the surface of the pressure side flank is smoothed, so that the coefficient of friction between the pressure side flank is reduced. In this case, when a load in the pushing direction is applied by the rotation of the cam, the adjustment screw may move greatly in the pushing direction due to excessive slip between the pressure side flank, and the valve lift amount may be reduced.

  The problem to be solved by the present invention is to provide a lash adjuster in which the coefficient of friction between the pressure side flank of the male screw and the female screw is unlikely to decrease when used for a long period of time.

  In order to solve the above problems, as a return spring that urges the adjustment screw in a direction protruding from the nut member, the adjusting screw is given a rotational force in a direction protruding from the nut member, and in a direction protruding from the nut member. The thing which also gives an axial force was used.

  In this case, when the adjusting screw moves in the protruding direction, the pressure side flank of the male screw and the female screw are separated from each other by the axial force of the return spring, and the lubricating oil enters between the pressure side flank. Therefore, the pressure side flank of the male screw and the female screw is not easily worn.

  The return spring is, for example, a combination of a torsion coil spring that applies a rotational force in a direction protruding from a nut member to an adjustment screw, and a compression coil spring that applies an axial force in a direction protruding from the nut member to the adjustment screw. Things can be adopted.

The present invention can be applied to, for example, the following lash adjuster.
1) The nut member is inserted into a receiving hole opened in the upper surface of the cylinder head, and the adjusting screw swingably supports the arm of the valve operating device at a protruding end from the nut member. Rush adjuster for equipment.
2) The nut member is fixed to a lifter body that is slidably inserted into a guide hole formed in a cylinder head, and the adjustment screw presses a valve stem of a valve operating device at a protruding end from the nut member. Rush adjuster for direct valve operating.
3) The nut member is inserted into a receiving hole opened on the lower surface of the arm that swings in accordance with the rotation of the cam, and the adjustment screw presses the valve stem of the valve gear at the protruding end from the nut member. Rush adjuster for rocker arm type valve gear.

  The male screw and the female screw may be any one of a sawtooth screw, a trapezoidal screw, and a triangular screw.

  The adjusting screw includes a slide member inserted in the nut member so as to be slidable in the axial direction, a male screw member supporting an insertion end of the slide member into the nut member, and having the male screw on an outer periphery, and the slide member And a disc spring sandwiched between male screw members.

  In the lash adjuster of the present invention, when the adjusting screw moves in the protruding direction, the pressure side flank of the male screw and the female screw are separated from each other by the axial force of the return spring, so that the lubricating oil easily enters between the pressure side flank. Therefore, when used for a long period of time, the pressure side flank of the male screw and the female screw is not easily worn, and the friction coefficient between the pressure side flank is difficult to decrease.

  FIG. 1 shows a valve gear incorporating a lash adjuster 1 according to a first embodiment of the present invention. This valve operating apparatus has a valve 4 provided in an intake port 3 of an engine cylinder head 2, a valve stem 5 connected to the valve 4, and an arm 7 that swings in response to rotation of a cam 6. .

  The valve stem 5 extends upward from the valve 4 and slidably penetrates the cylinder head 2. An annular spring retainer 8 is fixed to the upper outer periphery of the valve stem 5, and a valve spring 9 is incorporated between the lower surface of the spring retainer 8 and the upper surface of the cylinder head 2. The valve spring 9 urges the valve stem 5 upward via the spring retainer 8, and the valve 4 is seated on the valve seat 10 by the urging force.

  One end of the arm 7 is supported by the lash adjuster 1 so as to be swingable, and the other end is in contact with the upper end of the valve stem 5. A roller 11 is attached to the central portion of the arm 7, and the roller 11 is in contact with a cam 6 provided above the arm 7. The cam 6 is integrally formed with a camshaft 12 that rotates in synchronization with the crankshaft (not shown) of the engine. When the camshaft 12 rotates, a cam crest 6b that is raised with respect to the base circle 6a is formed. The arm 7 is pushed down via the roller 11.

  As shown in FIGS. 1 and 2, the lash adjuster 1 includes a cylindrical nut member 14 that is inserted into a receiving hole 13 that is open on the upper surface of the cylinder head 2, and a female screw 15 that is formed on the inner periphery of the nut member 14. An adjustment screw 17 having a male screw 16 on the outer periphery of the lower portion thereof, and a return spring 18 that urges the adjustment screw 17 in a direction protruding from the nut member 14.

  As shown in FIG. 2, the return spring 18 is a coil spring formed by winding a wire in a spiral shape so that an axial gap is formed between adjacent coils. It is inserted into a through hole 19 formed in the bottom portion 14 a and is prevented from rotating, and its upper end is locked in a locking hole 20 formed in the adjusting screw 17.

  As shown in FIG. 3, the return spring 18 has a free length when the adjusting screw 17 protrudes from the nut member 14, and from that state, the adjusting screw 17 is screwed into the nut member 14 to be torsionally deformed and compressed. Then, due to the elastic restoration, a rotational force in a direction protruding from the nut member 14 is applied to the adjustment screw 17 and an axial force in a direction protruding from the nut member 14 is also applied.

  As shown in FIG. 2, the male screw 16 and the female screw 15 are such that the flank angle of the pressure side flank 21 that receives pressure when a load in the direction of pushing the adjusting screw 17 into the nut member 14 is applied is the flank angle of the play side flank 22. It is formed in a larger sawtooth shape.

  An oil drain hole 23 communicating with the through hole 19 is formed on the inner bottom surface of the accommodation hole 13. Therefore, the lubricating oil that has flowed into the nut member 14 through the gap between the male screw 16 and the female screw 15 from the upper end surface of the nut member 14 passes through the through hole 19 and the oil drain hole 23 in order, and is discharged from the nut member 14. .

  As shown in FIG. 1, the adjusting screw 17 has a hemispherical protruding end 24 from the nut member 14, and the protruding end 24 fits into a recess 25 formed on the lower surface of the end of the arm 7. is doing. Here, the protruding end 24 is slidably in contact with the inner surface of the recess 25, and supports the arm 7 so as to be swingable by the sliding.

  Next, an operation example of the lash adjuster 1 will be described.

  When the cam 6 is rotated by the operation of the engine and the cam crest 6b of the cam 6 pushes down the arm 7, the valve 4 is separated from the valve seat 10 and the intake port 3 is opened. At this time, a load in the pushing direction is applied to the adjustment screw 17, but the pressure side flank 21 of the male screw 16 is received by the pressure side flank 21 of the female screw 15, and the axial position of the adjustment screw 17 is fixed.

  When the cam 6 further rotates and the cam crest 6b passes the position of the roller 11, the valve stem 5 is raised by the urging force of the valve spring 9, the valve 4 is seated on the valve seat 10, and the intake port 3 is close.

  Strictly speaking, when the cam crest 6b of the cam 6 pushes down the arm 7, a slight slip occurs between the pressure-side flanks 21, 21 of the male screw 16 and the female screw 15, and the adjustment screw 17 moves in the pushing direction due to the slip. However, when the cam crest 6b passes the position of the roller 11 and the load in the push-in direction is released, the adjustment screw 17 moves in the protruding direction while rotating by the force of the return spring 18 to return to the original position. Return to.

  Here, when the adjusting screw 17 moves in the pushing direction, the pressure side flank 21, 21 of the male screw 16 and the female screw 15 are in contact with each other as shown in FIG. On the other hand, when the adjusting screw 17 moves in the protruding direction, the pressure side flank 21, 21 of the male screw 16 and the female screw 15 are separated from each other by the axial force of the return spring 18 as shown in FIG. Then, as shown in FIG. 8, the play side flank 22, 22 of the male screw 16 and the female screw 15 are in contact with each other.

  During engine operation, when a difference in thermal expansion occurs between the components of the valve operating device such as the cylinder head 2, the valve stem 5, and the arm 7, and the distance between the cam 6 and the arm 7 increases, The amount of protrusion of the adjusting screw 17 when the cam 6 rotates and the load in the pushing direction is released is larger than the amount of pushing of the adjusting screw 17 when the cam crest 6b pushes down the arm 7. As a result, each time the cam 6 rotates, the adjusting screw 17 gradually moves in the protruding direction, so that no gap is generated between the base circle 6 a of the cam 6 and the roller 11.

  On the contrary, when the contact surface of the valve 4 and the valve seat 10 is worn, the biasing force of the valve spring 9 acts on the adjustment screw 17 even when the base circle 6a of the cam 6 is at the position of the roller 11. The amount of protrusion of the adjusting screw 17 when the cam 6 rotates and the load in the pushing direction is released is smaller than the amount of pushing of the adjusting screw 17 when the cam crest 6b of the cam 6 pushes down the arm 7. As a result, every time the cam 6 rotates, the adjusting screw 17 moves by several microns in the pushing direction and the valve stem 5 rises, so that no gap is generated between the contact surfaces of the valve 4 and the valve seat 10.

  In the lash adjuster 1, the pressure side flank 21, 21 of the male screw 16 and the female screw 15 are separated from each other by the axial force of the return spring 18 when the adjusting screw 17 moves in the protruding direction. Lubricating oil easily enters between 21. Therefore, when used for a long period of time, the pressure side flank 21 of the male screw 16 and the female screw 15 is hardly worn, and the friction coefficient between the pressure side flanks 21 and 21 is not easily lowered.

  In the above embodiment, the adjustment screw 17 having an integral structure is used. However, as shown in FIG. 4, the slide member 26A inserted into the nut member 14 so as to be slidable in the axial direction, and the nut member 14 of the slide member 26A. You may use the adjustment screw 26 which consists of the external thread member 26B which supports the insertion end to the outer periphery, and which has the external thread 16 on the outer periphery, and the disk spring 26C pinched | interposed between the slide member 26A and the external thread member 26B.

  In this way, when the engine stops in a high temperature state, and then the engine cools down and a contraction difference occurs between the constituent members of the valve gear, the disc spring 26C between the male screw member 26B and the slide member 26A. By compressing, the difference in shrinkage is absorbed. Therefore, when the engine is restarted, a gap due to a contraction difference between the constituent members of the valve operating device does not occur between the valve 4 and the valve seat 10, and compression leakage does not occur.

  Here, as a method of absorbing the difference in contraction generated between the components of the valve gear when the engine is cooled, a method of setting a large axial clearance between the male screw 16 and the female screw 15 is also conceivable. When the load due to the rotation of the cam 6 is received, the surface pressure acting between the pressure side flank 21 and 21 is increased, and the pressure side flank 21 is easily worn.

  On the other hand, as described above, if the disc spring 26C absorbs the contraction difference, the axial gap between the male screw 16 and the female screw 15 can be set small, so that the load in the pushing direction due to the rotation of the cam 6 can be set. The surface pressure acting between the pressure side flank 21 and 21 when received is reduced, and wear of the pressure side flank 21 can be effectively prevented.

  In the above-described embodiment, a single coil spring is used as the return spring 18 for applying the rotational force and the axial force to the adjustment screw 17. However, as shown in FIG. The return spring 27 may be configured by combining a torsion coil spring 27A that applies a rotational force to the adjusting screw 17 and a compression coil spring 27B that applies an axial force in a direction protruding from the nut member 14 to the adjusting screw 17. . In this case, the torsion coil spring 27A and the compression coil spring 27B are preferably reversed in the coil winding direction. In this way, it is possible to prevent the torsion coil spring 27A and the compression coil spring 27B from being entangled with each other.

  FIG. 9 shows a valve gear incorporating a lash adjuster 31 according to the second embodiment of the present invention. This valve operating apparatus has a valve 34 provided in the intake port 33 of the cylinder head 32 and a valve stem 35 connected to the valve 34.

  The valve stem 35 extends upward from the valve 34, and an annular spring retainer 36 is fixed to the upper outer periphery of the valve stem 35. The spring retainer 36 is biased upward by a valve spring 37, and the valve 34 is seated on the valve seat 38 by the biasing force.

  As shown in FIGS. 9 and 10, the lash adjuster 31 includes a lifter body 40 that is slidably inserted into a guide hole 39 formed in the cylinder head 32, and a nut member 41 that moves up and down integrally with the lifter body 40. And an adjusting screw 44 having a male screw 43 engaged with a female screw 42 formed on the inner periphery of the nut member 41 on the outer periphery, and a return spring 45 for biasing the adjusting screw 44 in a direction protruding from the nut member 41. .

  The lifter body 40 includes a cylindrical portion 46 and an end plate 47 provided at the upper end of the cylindrical portion 46, and a cam 48 is in contact with the upper surface of the end plate 47. The cam 48 is formed integrally with a camshaft 49 that rotates in synchronization with the crankshaft (not shown) of the engine. When the camshaft 49 rotates, the cam crest 48b that is raised with respect to the base circle 48a is formed on the lifter body 40. Is to be pushed down. The nut member 41 is fixed to the lifter body 40 with a retaining ring 50.

  As shown in FIG. 10, the male screw 43 and the female screw 42 are vertically trapezoidal trapezoidal screws. The return spring 45 is a coil spring formed by spirally winding a wire so that an axial gap is formed between adjacent coils, and an upper end of the return spring 45 is a latch formed on the upper surface of the nut member 41. The lower end of the groove 51 is locked in a locking hole 52 formed in the adjusting screw 44. The return spring 45 is torsionally deformed and compressively deformed, and by its elastic restoration, the adjusting screw 44 is given a rotational force in a direction protruding from the nut member 41 and an axial force in a direction protruding from the nut member 41 is also generated. Has been granted.

  The protruding end of the adjustment screw 44 from the nut member 41 contacts the spacer 53, and presses the upper end of the valve stem 35 through the spacer 53. The spacer 53 is prevented from rotating with respect to the nut member 41 by a retainer 54 fixed to the nut member 41, and can move up and down within a range of a notch 55 formed in the retainer 54.

  The end plate 47 of the lifter body 40 is formed with an oil passage hole 56 penetrating vertically. The lubricating oil supplied to the upper surface of the end plate 47 is introduced into the nut member 41 through the oil passage hole 56. It has become so. The lubricating oil introduced into the nut member 41 lubricates the male screw 43 and the female screw 42.

  In the lash adjuster 31, as in the first embodiment, when the cam crest portion 48b of the cam 48 pushes down the lifter body 40 and a load in the pushing direction is applied to the adjusting screw 44, the pressure side flank 57 of the male screw 43 becomes the female screw. 42, the axial position of the adjusting screw 44 with respect to the nut member 41 is fixed. Strictly, at this time, a slight slip occurs between the pressure side flank 57, 57 of the male screw 43 and the female screw 42, and the adjustment screw 44 moves in the pushing direction by the slip, but the cam 48 further rotates to push in the pushing direction. When the load is released, the adjustment screw 44 moves in the protruding direction while rotating by the force of the return spring 45, and returns to the original position.

  In the lash adjuster 31, the pressure side flank 57, 57 of the male screw 43 and the female screw 42 are separated from each other by the axial force of the return spring 45 when the adjusting screw 44 moves in the protruding direction. The lubricating oil easily enters between 57. Therefore, when used for a long period of time, the pressure side flank 57 of the male screw 43 and the female screw 42 is not easily worn, and the friction coefficient between the pressure side flank 57 and 57 is not easily lowered.

  FIG. 11 shows a valve gear incorporating a lash adjuster 61 according to a third embodiment of the present invention. This valve operating apparatus has a valve 64 provided in an intake port 63 of a cylinder head 62 of the engine, a valve stem 65 connected to the valve 64, and an arm 67 that swings according to the rotation of a cam 66. .

  The valve stem 65 extends upward from the valve 64, and a spring retainer 68 is fixed to the upper portion of the valve stem 65. The spring retainer 68 is biased upward by a valve spring 69, and the valve 64 is seated on the valve seat 70 by the biasing force.

  The arm 67 is supported at the center by a fulcrum shaft 71 so as to be swingable. A roller 72 that contacts the cam 66 is attached to one end of the arm 67, and a lash adjuster 61 is incorporated into the other end of the arm 67. A cam 66 provided below the arm 67 is integrally formed with a camshaft 73 that rotates in synchronization with an engine crankshaft (not shown). When the camshaft 73 rotates, the cam 66 rotates relative to the base circle 66a. The cam crest 66b that is raised in this manner presses the roller 72 to swing the arm 67.

  As shown in FIGS. 11 and 12, the lash adjuster 61 includes a cylindrical nut member 75 that is inserted into the accommodation hole 74 that is opened in the lower surface of the arm 67, and a female screw 76 that is formed on the inner periphery of the nut member 75. An adjustment screw 78 having a male screw 77 that engages with the screw on its outer periphery, and a return spring 79 that urges the adjustment screw 78 in a direction to protrude from the nut member 75 are provided.

  As shown in FIG. 12, the return spring 79 is a coil spring formed by winding a wire in a spiral shape so that an axial gap is formed between adjacent coils. It is inserted into a through hole 80 formed on the inner bottom surface and is prevented from rotating, and the lower end is locked to a locking hole 81 formed in the adjusting screw 78. The return spring 79 is torsionally deformed and compressively deformed, and by its elastic restoration, the adjusting spring 78 is given a rotational force in a direction protruding from the nut member 75 and an axial force in a direction protruding from the nut member 75 is also applied. Has been granted. The protruding end of the adjusting screw 78 from the nut member 75 presses the upper end of the valve stem 65.

  The male screw 77 and the female screw 76 are vertically symmetrical triangular screws. The lubricating oil splashed on the upper surface of the arm 67 is introduced into the accommodation hole 74 through the through hole 80 and lubricates between the male screw 77 and the female screw 76. The nut member 75 is prevented from rotating around the arm 67 by caulking the edge of the accommodation hole 74.

  As in the first embodiment, the lash adjuster 61 is configured such that when the cam crest 66b of the cam 66 pushes up the end of the arm 67 and a load in the pushing direction is applied to the adjusting screw 78, the pressure side flank of the male screw 77 is pressed. 82 is received by the pressure side flank 82 of the female screw 76, and the axial position of the adjusting screw 78 with respect to the nut member 75 is fixed. Strictly, at this time, a slight slip occurs between the pressure side flank 82 and 82 of the male screw 77 and the female screw 76, and the adjustment screw 78 moves in the pushing direction due to the sliding, but the cam 66 further rotates and pushes in the pushing direction. When the load is released, the adjustment screw 78 moves in the protruding direction while rotating by the force of the return spring 79, and returns to the original position.

  In the lash adjuster 61, when the adjusting screw 78 moves in the protruding direction, the pressure side flank 82, 82 of the male screw 77 and the female screw 76 are separated from each other by the axial force of the return spring 79. The lubricating oil easily enters between 82. Therefore, when used for a long period of time, the pressure side flank 82 of the male screw 77 and the female screw 76 is not easily worn, and the friction coefficient between the pressure side flank 82 and 82 is hardly lowered.

The front view which shows the valve operating apparatus incorporating the lash adjuster of 1st Embodiment of this invention FIG. 1 is an enlarged cross-sectional view in the vicinity of a lash adjuster of the valve gear shown in FIG. The figure which shows the state which the adjustment screw shown in FIG. 2 protruded from the nut member Sectional drawing which shows the modification of the lash adjuster shown in FIG. Sectional drawing which shows the other modification of the lash adjuster shown in FIG. Enlarged cross-sectional view of male screw and female screw showing the adjustment screw moving in the pushing direction and the pressure side flank contacting each other Enlarged cross-sectional view of male screw and female screw showing the process of adjusting screw moving in the protruding direction Enlarged cross-sectional view of male screw and female screw showing the adjustment screw moving in the protruding direction and the play side flank contacting each other The front view which shows the valve operating apparatus incorporating the lash adjuster of 2nd Embodiment of this invention. FIG. 9 is an enlarged cross-sectional view in the vicinity of the lash adjuster of the valve gear shown in FIG. Front view showing a valve gear incorporating a lash adjuster according to a third embodiment of the present invention. FIG. 11 is an enlarged sectional view in the vicinity of a lash adjuster of the valve gear shown in FIG.

Explanation of symbols

1 lash adjuster 2 cylinder head 7 arm 13 receiving hole 14 nut member 15 female screw 16 male screw 17 adjusting screw 18 return spring 21 pressure side flank 24 projecting end 26 adjusting screw 26A slide member 26B male screw member 26C disc spring 27 return spring 27A torsion coil spring 27B Compression coil spring 31 Rush adjuster 32 Cylinder head 35 Valve stem 39 Guide hole 40 Lifter body 41 Nut member 42 Female screw 43 Male screw 44 Adjustment screw 45 Return spring 57 Pressure side flank 61 Rush adjuster 65 Valve stem 66 Cam 67 Arm 74 Housing hole 75 Nut Member 76 Female screw 77 Male screw 78 Adjust screw 79 Return spring 82 Pressure side flank

Claims (9)

A nut member (14) having a female screw (15) on the inner periphery, an adjustment screw (17) having a male screw (16) threadedly engaged with the female screw (15) on the outer periphery, and the adjustment screw (17) as a nut member A return spring (18) biasing in a direction protruding from (14), and when an axial load is applied in a direction of pushing the adjusting screw (17) into the nut member (14), In the lash adjuster (1) of the valve gear that receives the load by the pressure side flank (21) of the male screw (16) and the female screw (15),
The return spring (18) applies a rotational force in a direction protruding from the nut member (14) to the adjustment screw (17) and also an axial force in a direction protruding from the nut member (14). Rush adjuster.   The return spring (27) applies a rotational force in a direction protruding from the nut member (14) to the adjustment screw (17), and an axial force in a direction protruding from the nut member (14) The lash adjuster according to claim 1, wherein the lash adjuster is combined with a compression coil spring (27 </ b> B) that imparts to the adjustment screw (17).   The nut member (14) is inserted into a receiving hole (13) opened on the upper surface of the cylinder head (2), and the adjustment screw (17) is moved by a protruding end (24) from the nut member (14). The lash adjuster according to claim 1 or 2, wherein the arm (7) of the valve device is swingably supported.   The nut member (41) is fixed to a lifter body (40) that is slidably inserted in a guide hole (39) formed in a cylinder head (32), and the adjustment screw (44) The lash adjuster according to claim 1 or 2, wherein the valve stem (35) of the valve gear is pressed by a protruding end from (41).   The nut member (75) is inserted into a receiving hole (74) opened in the lower surface of an arm (67) that swings according to the rotation of the cam (66), and the adjustment screw (78) is inserted into the nut member (74). The lash adjuster according to claim 1 or 2, wherein the valve stem (65) of the valve operating device is pressed by a protruding end from 75).   The lash adjuster according to any one of claims 1 to 5, wherein the male screw (16) and the female screw (15) are sawtooth screws.   The lash adjuster according to any one of claims 1 to 5, wherein the male screw (43) and the female screw (42) are trapezoidal screws.   The lash adjuster according to any one of claims 1 to 5, wherein the male screw (77) and the female screw (76) are triangular screws.   The adjustment screw (26) supports a slide member (26A) inserted in the nut member (14) so as to be slidable in the axial direction, and an insertion end of the slide member (26A) into the nut member (14). The male screw member (26B) having the male screw (16) on the outer periphery, and a disc spring (26C) sandwiched between the slide member (26A) and the male screw member (26B). The lash adjuster according to any one of the above.

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