JP2010065615A - Lash adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lash adjuster in which wear debris hardly accumulates between a male screw and a female screw. <P>SOLUTION: This lash adjuster has: a bottomed cylindrical housing 14 inserted into a storage hole 13 opened on an upper face of a cylinder head 2; an adjust screw 17 having the male screw 16 on its outer periphery that engages by screwing with the female screw 15 formed on the inner periphery of the housing 14; and a torsion spring 18 for applying rotational force to the adjust screw 17 in the direction to project upward from the housing 14. An arm 7 of a valve gear is swingably supported by a projecting end 24 of the adjust screw 17 from the housing 14. A through-hole 28 communicating the inside and the outside of the housing 14 is formed in a bottom part 21 of the housing 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 at the intake port or exhaust port of an engine, the central part of the arm supported so as to be swingable with one end as a fulcrum is pushed down by a cam, and the valve stem is What is pushed down is known.

  In this valve operating apparatus, a gap between constituent members of the valve operating device changes due to a difference in thermal expansion generated between the constituent members of the valve operating device during operation of the engine, and abnormal noise and compression leakage may occur due to the change in the clearance. There is. 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 or compression leakage may occur due to the change in the gap.

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

  As such a lash adjuster, an adjustment screw having a bottomed cylindrical housing inserted into a receiving hole opened on the upper surface of the cylinder head and a male screw on the outer periphery that engages with a female screw formed on the inner periphery of the housing. And a torsion spring for applying a rotational force in a direction projecting upward from the housing to the adjustment screw, and supporting the arm of the valve gear so as to be swingable at a projecting end of the adjustment screw from the housing. Known (Patent Document 1).

  In the lash adjuster, when a force in the pushing direction is applied to the adjustment screw by the rotation of the cam, the male screw of the adjustment screw is received by the female screw of the housing, and the axial position of the adjustment screw is fixed.

When the relative position of the arm and cylinder head changes due to thermal expansion of the valve operating device, etc., the adjusting screw moves in the axial direction while rotating in the housing according to the change in position, and the valve operating device Absorbs changes in gaps between components.
Japanese Utility Model Publication No. 64-34407

  By the way, since the bottom of the housing of the lash adjuster is closed, when lubricating oil splashed during engine operation is introduced into the housing and lubricated between the male screw and the female screw, the lubricating oil is not contained in the housing. It tends to stay and the flow of lubricating oil between the external thread and internal thread is poor. For this reason, there is a problem in that wear powder due to contact between the male screw and the female screw stays between the male screw and the female screw, and the wear powder promotes wear of the male screw and the female screw, thereby reducing the life of the lash adjuster.

  Further, when the lash adjuster is inserted into the accommodation hole on the upper surface of the cylinder head, the air in the accommodation hole is compressed to cause resistance, so that the assembly work to the cylinder head is complicated.

  The problem to be solved by the present invention is to provide a lash adjuster in which wear powder is less likely to stay between a male screw and a female screw.

  In order to solve the above problems, a through-hole that communicates the inside and outside of the housing is formed at the bottom of the housing. If it does in this way, since the lubricating oil in a housing will be discharged | emitted through a through-hole, the flow of the lubricating oil between a male screw and a female screw will be smooth, and abrasion powder will not retain easily between a male screw and a female screw. Also, when the lash adjuster is inserted into the receiving hole on the upper surface of the cylinder head, the air in the receiving hole is discharged through the inside of the lash adjuster, so the insertion resistance to the receiving hole is small and the assembly work to the cylinder head Excellent in properties.

  The housing may adopt a configuration including a cylindrical portion having a cylindrical surface on the inner periphery and a nut portion provided continuously below the cylindrical portion and having the female screw on the inner periphery, and the adjusting screw. Adopts a configuration comprising a pivot member inserted into the cylindrical portion so as to be slidable in the axial direction, a male screw member having the male screw on the outer periphery, and an elastic member sandwiched between the pivot member and the male screw member. be able to. In this way, when the engine stops at a high temperature, and then the engine cools down and a contraction difference occurs between the components of the valve gear, the elastic member compresses to absorb the contraction difference. can do.

  The pivot member preferably has a lubricating oil introduction groove extending in the axial direction on the outer periphery. If it does in this way, it will become possible to introduce into a housing efficiently lubricating oil splashed during engine operation.

  Further, the inner diameter of the cylindrical portion can be made larger than the outer diameter of the male screw member, and an annular gap can be formed between the upper outer periphery of the male screw member and the inner periphery of the cylindrical portion. In this way, the lubricating oil introduced into the housing through the lubricating oil introduction groove is distributed throughout the entire circumference through the annular gap, so that the lubricating oil is reliably supplied between the male screw and the female screw.

  Examples of the torsion spring include a torsion coil spring, a spring, and a bamboo spring. The male screw and the female screw may be any of a triangular screw, a trapezoidal screw, and a sawtooth screw.

  In the lash adjuster of the present invention, the lubricating oil in the housing is discharged from the through hole at the bottom of the housing, so that the lubricating oil flows smoothly between the male screw and the female screw, and wear powder stays between the male screw and the female screw. Hateful.

  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 bottomed cylindrical housing 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 housing 14. An adjustment screw 17 having a male screw 16 on the outer periphery thereof and a torsion spring 18 for urging the adjustment screw 17.

  As shown in FIG. 2, the adjusting screw 17 includes a pivot member 17A having a cylindrical surface 19 on the outer periphery, a male screw member 17B having a male screw 16 on the outer periphery, and a spring washer 17C sandwiched between the pivot member 17A and the male screw member 17B. It consists of. On the other hand, the housing 14 includes a cylindrical portion 14A having a cylindrical surface 20 on the inner periphery, and a nut portion 14B provided continuously below the cylindrical portion 14A and having a female screw 15 on the inner periphery.

  The pivot member 17A is inserted into the cylindrical portion 14A so as to be slidable in the axial direction. The fitting of the cylindrical surface 19 and the cylindrical surface 20 prevents the pivot member 17A from falling. The male screw member 17B is screwed into the nut portion 14B. The male screw member 17B supports the pivot member 17A via a spring washer 17C. As the spring washer 17C, for example, a disc spring washer, a toothed washer, a corrugated washer, or the like can be used. A bottom portion 21 is press-fitted and fixed to the lower end of the nut portion 14B.

  The male screw 16 and the female screw 15 are formed in a sawtooth shape in which the flank angle of the pressure side flank that receives pressure when a load is applied in a direction in which the pivot member 17A is pushed into the housing 14 is larger than the flank angle of the play side flank. .

  The torsion spring 18 is a torsion coil spring in which a linear material is spirally wound. The lower end of the torsion spring 18 is inserted into a locking hole 22 formed in the bottom portion 21, and the upper end is inserted into a locking hole 23 penetrating the male screw member 17B up and down. The rotational force in the direction in which the member 17A protrudes from the housing 14 is applied to the male screw member 17B.

  As shown in FIG. 1, in the pivot member 17 </ b> A, a protruding end 24 from the housing 14 is formed in a hemispherical shape, and the protruding end 24 is fitted in a recess 25 formed on the lower surface of the end of the arm 7. . 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.

  As shown in FIG. 2, a lubricant introduction groove 26 extending in the axial direction is formed on the outer periphery of the pivot member 17A. The lubricating oil introduction groove 26 extends from the protruding portion of the pivot member 17A from the housing 14 to the insertion end of the pivot member 17A into the housing 14, and the lubricating oil splashed during engine operation causes the lubricating oil introduction groove 26 to pass through. And is introduced into the housing 14.

  The inner diameter of the cylindrical portion 14A is larger than the outer diameter of the male screw member 17B. An annular clearance is formed between the upper outer periphery of the male screw member 17B and the inner periphery of the cylindrical portion 14A, and the lubricating oil introduced into the housing 14 through the lubricating oil introduction groove 26 is completely removed by the annular clearance 27. It is designed to go around the lap.

  A through hole 28 that communicates the inside and outside of the housing 14 is formed in the bottom portion 21 of the housing 14, and lubricating oil in the housing 14 is formed in the through hole 28 and an oil drain hole 29 formed in the bottom surface of the accommodation hole 13. And are discharged to the outside through the above.

  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 pivot member 17A, but the pressure side flank of the male screw 16 is received by the pressure side flank of the female screw 15, and the axial positions of the male screw member 17B and the pivot member 17A are 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 flank of the male screw 16 and the female screw 15, and the male screw member 17B moves in the pushing direction by the slip. When the cam crest 6b passes the position of the roller 11 and the load in the pushing direction is released, the male screw member 17B moves in the protruding direction while rotating by the force of the torsion spring 18, and returns to the original position.

  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 protruding amount of the male screw member 17B when the cam 6 rotates and the load in the pressing direction is released is larger than the pressing amount of the male screw member 17B when the cam crest 6b pushes down the arm 7. As a result, every time the cam 6 rotates, the pivot member 17A and the male screw member 17B gradually move in the protruding direction, so that no gap is generated between the base circle 6a 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 is applied to the pivot member 17A and the male screw member 17B even when the base circle 6a of the cam 6 is at the position of the roller 11. Therefore, the amount of protrusion of the male screw member 17B when the cam 6 rotates and the load in the pushing direction is released is larger than the amount of push of the male screw member 17B when the cam crest 6b of the cam 6 pushes down the arm 7. Becomes smaller. As a result, each time the cam 6 rotates, the male screw member 17B and the pivot member 17A move by several microns in the pushing direction, and the valve stem 5 rises, so that a gap is generated between the contact surfaces of the valve 4 and the valve seat 10. Absent.

  Since the lash adjuster 1 has a lubricating oil introduction groove 26 formed on the outer periphery of the pivot member 17A, the lubricating oil splashed during engine operation can be efficiently introduced into the housing 14, and the male screw 16 and The lubricity of the female screw 15 is excellent.

  Further, in this lash adjuster 1, since the lubricating oil in the housing 14 is discharged through the through hole 28, the lubricating oil flows smoothly between the male screw 16 and the female screw 15, and between the male screw 16 and the female screw 15. Wear powder is less likely to stay on the surface.

  Further, the lash adjuster 1 is configured such that the lubricating oil introduced into the housing 14 through the lubricating oil introduction groove 26 is surrounded by the annular gap 27 between the upper outer periphery of the male screw member 17B and the inner periphery of the cylindrical portion 14A. Therefore, the supply of lubricating oil between the male screw 16 and the female screw 15 is reliable.

  Further, when the lash adjuster 1 is inserted into the accommodation hole 13, the air in the accommodation hole 13 is discharged through the inside of the lash adjuster 1, so that the insertion resistance into the accommodation hole 13 is small, and the cylinder head 2 Excellent assembly workability.

  Further, the lash adjuster 1 is compressed when the spring washer 17C is compressed when the engine is stopped in a high temperature state and then the engine is cooled to cause a contraction difference between the constituent members of the valve gear. Absorbs shrinkage differences. 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.

  When a torsion coil spring is used as the torsion spring 18, the torsion spring 18 may be a cylinder wound as shown in FIG. 2, or a cone wound as shown in FIG. May be.

  In the above embodiment, the spring washer 17C is used as an elastic member sandwiched between the pivot member 17A and the male screw member 17B. However, another elastic member (for example, a compression coil spring) may be used instead of the spring washer 17C. .

  4 and 5 show a lash adjuster 31 according to a second embodiment of the present invention. This lash adjuster 31 uses the torsion spring 18 of the first embodiment as a bamboo spring. Hereinafter, portions corresponding to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The external thread 16 on the outer periphery of the external thread member 17B and the internal thread 15 on the inner periphery of the housing 14 are vertically symmetrical trapezoidal screws.

  The torsion spring 18 is a bamboo child spring in which a thin plate material is spirally wound. The large-diameter end of the torsion spring 18 is prevented from rotating to the bottom 21 of the housing 14, and the small-diameter end is inserted into a slit formed in the protrusion 32 at the insertion end of the male screw member 17B into the housing 14, and its torsional deformation Thus, the rotational force in the direction in which the pivot member 17A protrudes from the housing 14 is applied to the male screw member 17B.

  Similarly to the first embodiment, the lash adjuster 31 is also formed with the lubricating oil introduction groove 26 on the outer periphery of the pivot member 17A. Therefore, the lubricating oil splashed during engine operation is efficiently introduced into the housing 14. Therefore, the lubricity of the male screw 16 and the female screw 15 is excellent. Since the lubricating oil in the housing 14 is discharged through the through hole 28, the lubricating oil flows smoothly between the male screw 16 and the female screw 15, and wear powder hardly stays between the female screw 15 and the male screw 16.

  FIG. 6 shows a lash adjuster 41 according to the third embodiment of the present invention. In this lash adjuster 41, the torsion spring 18 of the first embodiment is a spring. Hereinafter, portions corresponding to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The external thread 16 on the outer periphery of the external thread member 17B and the internal thread 15 on the inner periphery of the housing 14 are vertically symmetrical triangular screws.

  The torsion spring 18 is a mainspring spring in which a thin plate material is wound in a spiral shape. The large-diameter end of the torsion spring 18 is prevented from rotating to the bottom 21 of the housing 14, and the small-diameter end is inserted into a slit formed in the protrusion 42 at the insertion end of the male screw member 17B into the housing 14, and the torsion spring 18 is twisted. By the deformation, the rotational force in the direction in which the pivot member 17A protrudes from the housing 14 is applied to the male screw member 17B.

  Similarly to the first embodiment, the lash adjuster 41 is also formed with the lubricating oil introduction groove 26 on the outer periphery of the pivot member 17A. Therefore, the lubricating oil splashed during engine operation is efficiently introduced into the housing 14. Therefore, the lubricity of the male screw 16 and the female screw 15 is excellent. Since the lubricating oil in the housing 14 is discharged through the through hole 28, the lubricating oil flows smoothly between the male screw 16 and the female screw 15, and wear powder hardly stays between the female screw 15 and the male screw 16.

  In each of the above embodiments, the bottom portion 21 of the housing 14 is formed separately from the housing 14, and the bottom portion 21 is fixed to the lower end of the housing 14, but the housing 14 and the bottom portion 21 may be formed integrally. Good.

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. Enlarged sectional view showing a modification of the lash adjuster shown in FIG. The expanded sectional view which shows the lash adjuster of 2nd Embodiment of this invention Sectional view along line VV in FIG. The expanded sectional view which shows the lash adjuster of 3rd Embodiment of this invention

Explanation of symbols

1 Rush Adjuster 2 Cylinder Head 7 Arm 13 Housing Hole 14 Housing 14A Cylindrical Part 14B Nut 15 Female Thread 16 Male Thread 17 Adjusting Screw 17A Pivot Member 17B Male Thread Member 17C Spring Washer 18 Torsion Spring 20 Cylindrical Surface 21 Bottom 24 Protruding End 26 Lubricating Oil Introduction Groove 27 Annular gap 28 Through hole 31, 41 Rush adjuster

Claims (6)

  Screw engagement with a bottomed cylindrical housing (14) inserted into a receiving hole (13) opened in the upper surface of the cylinder head (2) and a female screw (15) formed on the inner periphery of the housing (14) An adjusting screw (17) having a male screw (16) on the outer periphery, and a torsion spring (18) for applying a rotational force in a direction protruding upward from the housing (14) to the adjusting screw (17), In the lash adjuster in which the arm (7) of the valve gear is swingably supported by the projecting end (24) of the adjustment screw (17) from the housing (14), the housing (14) is provided with a housing at the bottom (21). A lash adjuster characterized in that a through-hole (28) communicating between the inside and outside of (14) is formed.   The housing (14) has a cylindrical portion (14A) having a cylindrical surface (20) on the inner periphery, and a nut provided continuously below the cylindrical portion (14A), and has the female screw (15) on the inner periphery. Male screw having a pivot member (17A) inserted into the cylindrical portion (14A) so as to be slidable in the axial direction and the male screw (16) on the outer periphery. The lash adjuster according to claim 1, comprising a member (17B) and an elastic member (17C) sandwiched between the pivot member (17A) and the male screw member (17B).   The lash adjuster according to claim 2, wherein a lubricating oil introduction groove (26) extending in the axial direction is formed on an outer periphery of the pivot member (17A).   The inner diameter of the cylindrical portion (14A) is larger than the outer diameter of the male screw member (17B), and an annular gap (27) is formed between the upper outer periphery of the male screw member (17B) and the inner periphery of the cylindrical portion (14A). The lash adjuster according to claim 3, wherein the lash adjuster is formed.   The lash adjuster according to any one of claims 1 to 4, wherein the torsion spring (18) is any one of a torsion coil spring, a spring, and a bamboo spring.   The lash adjuster according to any one of claims 1 to 5, wherein the male screw (16) and the female screw (15) are triangular screws, trapezoidal screws, or sawtooth screws.

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