JP2009203975A - Lash adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a lash adjuster case from floating during engine operation while shortening the time required when inserting the lash adjuster into a bottomed hole of a cylinder head. <P>SOLUTION: A lash adjuster 1 comprises a cylindrical case 13 inserted into a bottomed hole 12 opening to the top surface of a cylinder head 2, an adjust screw 16 including in the outer periphery a male screw 15 threadedly engaged with a female screw 14 formed in the inner periphery of the case 13 and a return spring 18 assembled between an insertion end into the case 13 of the adjust screw 16 and a bottom member 17 provided to the lower end of the case 13, and biases the adjust screw 16 in an upward projecting direction from the case 13 by the return spring 18, wherein an air vent hole 24 for communicating with the outside from between the bottom member 17 of the case 13 and the bottom of the bottomed hole 12. <P>COPYRIGHT: (C)2009,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 moved at the other end of the arm. 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 is generated 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, a cylindrical case inserted into a bottomed hole opened on the upper surface of the cylinder head, and an adjustment screw having a male screw on its outer periphery that engages with a female screw formed on the inner periphery of the case, And a return spring built in between the insertion end of the adjustment screw into the case and the bottom provided at the lower end of the case, and the return spring biases the adjustment screw in a direction protruding upward from the case What was made to do is known (patent documents 1 and 2).

  Here, in Patent Document 1, a compression coil spring that applies an axial force in a direction protruding from the case to the adjustment screw is used as the return spring. Moreover, in patent document 2, the torsion spring which provides the adjusting screw with the rotational force of the direction which protrudes from a case is used as a return spring.

  In these lash adjusters, the protruding end of the adjusting screw from the case fits into a recess formed in the arm of the valve gear, and supports the arm so that it can swing around the protruding end. In this state, when a force in the pushing direction is applied to the adjustment screw by the rotation of the cam, the external screw on the outer periphery of the adjustment screw is received by the internal screw on the inner periphery of the case, and the axial position of the adjustment screw is fixed.

On the other hand, 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 case according to the change in position, and the valve operating device Absorbs changes in gaps between components.
JP 2005-273510 A Japanese Utility Model Publication No. 64-34407

  By the way, the lash adjuster receives the force in the pushing direction acting on the adjusting screw with the female screw on the inner periphery of the case, so that no hydraulic pressure is required. Therefore, it is not necessary to provide an oil supply passage to the lash adjuster, and there is no opening communicating with the outside on the inner surface of the bottomed hole into which the lash adjuster is inserted.

  Therefore, when the lash adjuster is inserted into the bottomed hole of the cylinder head, reaction force is generated at the bottom of the case due to the air trapped between the bottom of the case and the bottom of the bottomed hole, and the insertion is completed. It took a long time to do.

  In addition, when air is present between the bottom of the case and the bottom of the bottomed hole after the lash adjuster is inserted into the bottomed hole of the cylinder head, the air is thermally expanded during engine operation, Sometimes came up. When the case is lifted up, when the force in the pushing direction is applied to the adjustment screw, the case sinks due to the compression of the air.Therefore, the valve lift amount may be reduced, or the valve may be seated impactfully on the valve seat. May cause abnormal noise.

  The problem to be solved by the present invention is to reduce the time required to insert the lash adjuster into the bottomed hole of the cylinder head and to prevent the lash adjuster case from floating during engine operation.

  In order to solve the above-described problem, an air vent passage is provided that communicates with the outside from between the bottom of the case and the bottom of the bottomed hole.

As the air vent passage, for example, one having the following configuration can be adopted.
1) An air vent hole formed in the bottom of the bottomed hole.
2) A vertical groove formed on the outer periphery of the case.
3) Spline grooves formed on the outer periphery of the case.
4) A spiral groove formed on the outer periphery of the case.
5) A vertical groove formed on the inner periphery of the bottomed hole.
6) A spline groove formed on the inner periphery of the bottomed hole.
7) A spiral groove formed on the inner periphery of the bottomed hole.

  When the air vent passage having the structure of 1) is adopted, it is preferable that an oil passage hole that vertically penetrates the bottom of the case is provided and the lower end of the oil passage hole is communicated with the air vent hole.

  Further, the present invention can be applied to a lash adjuster that uses a compression coil spring that applies an axial force in a direction protruding from the case to the adjustment screw as the return spring, and a rotational force in a direction protruding from the case. Can be applied to a lash adjuster that uses a torsion spring that imparts to the adjusting screw as the return spring.

  Examples of the torsion spring constituting the return spring include a torsion coil spring, a mainspring spring, and a bamboo spring.

  As the male screw and the female screw, any of a triangular screw, a trapezoidal screw, and a sawtooth screw may be adopted.

  When the lash adjuster of the present invention is inserted into the bottomed hole of the cylinder head, the air between the bottom of the case and the bottom of the bottomed hole is discharged to the outside through the air vent passage, and the inside of the bottomed hole is large. Since the atmospheric pressure is maintained, no reaction force is generated at the bottom of the case, and the time required to complete the insertion is short.

  In addition, even if air exists between the bottom of the case and the bottom of the bottomed hole, and the air thermally expands during engine operation, the increased air is exhausted to the outside through the air vent passage. Therefore, the case does not rise and the operation reliability is high.

  Further, as the air vent passage, an air vent hole formed in the bottom of the bottomed hole is adopted, and an oil passage hole that vertically penetrates the bottom portion of the case is provided. When the engine is running, the engine oil splashed onto the cylinder head is the engine oil splashed on the cylinder head. When lubricating between the male screw of the adjustment screw and the female screw of the case, the engine oil that has flowed into the case The oil is discharged from the case through the oil passage hole and the air vent hole. Therefore, the contamination and wear powder mixed in the engine oil are unlikely to stay between the male screw of the adjusting screw and the female screw of the case, and the male screw and the female screw are not easily worn.

  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, 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.

  As shown in FIG. 2, the lash adjuster 1 is screw-engaged with a cylindrical case 13 inserted into a bottomed hole 12 opened on the upper surface of the cylinder head 2 and a female screw 14 formed on the inner periphery of the case 13. An adjusting screw 16 having a male screw 15 on the lower outer periphery, a bottom member 17 fixed to the lower end of the case 13, and a return spring 18 incorporated between the insertion end of the adjusting screw 16 into the case 13 and the bottom member 17. It consists of.

  The male screw 15 and the female screw 14 are formed in a sawtooth shape having an asymmetric cross section along the axis, and the flank of the pressure side flank 19 that receives pressure when a force in the direction of pushing the adjusting screw 16 into the case 13 is applied. The angle is larger than the flank angle of the play side flank 20.

  The return spring 18 is a compression coil spring. The return spring 18 has a lower end supported by the bottom member 17 of the case 13 and an upper end that applies an axial force in a direction protruding from the case 13 via the spring seat 21 to the adjustment screw 16. The adjusting screw 16 is urged by the axial force in a direction protruding upward from the case 13. As shown in FIG. 1, the protruding end 22 of the adjustment screw 16 from the case 13 fits into a recess 23 formed on the lower surface of the end of the arm 7, and the arm 7 can swing around the protruding end 22. I support it.

  The bottom of the bottomed hole 12 is formed with an air vent hole 24 that communicates with the outside through the inside of the cylinder head 2. When the lash adjuster 1 is inserted into the bottomed hole 12 as shown in FIG. In addition, air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged to the outside through the air vent hole 24.

  Further, as shown in FIG. 2, an oil passage hole 25 penetrating vertically is formed in the bottom member 17, and the lower end of the oil passage hole 25 communicates with the air vent hole 24. When the space between the male screw 15 and the female screw 14 is lubricated with the applied engine oil, the engine oil that has flowed into the case 13 passes through the oil passage hole 25 and the air vent hole 24 in order and is discharged from the case 13. It has become.

  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 6a 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 force in the pushing direction acts on the adjustment screw 16, but the rotation of the adjustment screw 16 is prevented by the frictional resistance between the pressure side flanks 19, 19 of the male screw 15 and the female screw 14, and as a result, the shaft of the adjusting screw 16. The direction position is fixed.

  Further, when the cam 6 rotates and the cam crest 6 a 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. Close.

  In addition, when the engine 6 is operating and 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, the return between the cam 6 and the arm 7 increases. Since the adjusting screw 16 moves in the protruding direction while rotating by the urging force of the spring 18, there is no gap between the base circle 6 b 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 urging force of the valve spring 9 is applied to the adjusting screw 16 as a pushing load even when the base circle 6b of the cam 6 is at the position of the roller 11. In order to continue, minute slip generated between the male screw 15 and the female screw 14 generated when the cam crest 6a passes the position of the roller 11 is accumulated, and the adjusting screw 16 gradually moves in the pushing direction. As a result, the valve stem 5 is raised, so that no gap is generated between the contact surfaces of the valve 4 and the valve seat 10.

  When the lash adjuster 1 is inserted into the bottomed hole 12, the air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged outside through the air vent hole 24, and the inside of the bottomed hole 12 is Since the atmospheric pressure is maintained, no reaction force is generated in the bottom member 17, and the time required for completing the insertion is short.

  Further, in the lash adjuster 1, even when air exists between the bottom member 17 and the bottom of the bottomed hole 12, and the air is thermally expanded during engine operation, the air increased by the thermal expansion is air. Since the case 13 is discharged to the outside through the hole 24, the case 13 does not rise and the operation reliability is high.

  Further, the lash adjuster 1 is configured such that when the engine oil is lubricated between the male screw 15 and the female screw 14 with engine oil splashed on the cylinder head 2 during engine operation, The air is discharged from the case 13 through the air vent hole 24. Therefore, the contamination and wear powder mixed in the engine oil are less likely to stay between the male screw 15 and the female screw 14, and the male screw 15 and the female screw 14 are less likely to wear.

  In the above embodiment, the air vent passage 24 formed in the bottom of the bottomed hole 12 is described as an example as the air vent passage communicating from the bottom member 17 and the bottom of the bottomed hole 12 to the outside. Instead of the air vent hole 24, a longitudinal groove 26 may be formed on the outer periphery of the case 13, as shown in FIG. Even in this case, when the lash adjuster 1 is inserted into the bottomed hole 12, the air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged to the outside through the vertical groove 26.

  As shown in FIG. 5, spline grooves 27 formed at a constant pitch on the outer periphery of the case 13 may be adopted as the air vent passage communicating from the bottom member 17 and the bottom of the bottomed hole 12 to the outside. In this case, since the spline groove 27 on the outer periphery of the case 13 can be rolled, the manufacturing cost of the case 13 can be reduced as compared with the case where the air vent passage is formed on the outer periphery of the case 13 by cutting. .

  Further, as shown in FIG. 6, a spiral groove 28 formed on the outer periphery of the case 13 may be adopted as the air vent passage communicating from the bottom member 17 and the bottom of the bottomed hole 12 to the outside. Even in this case, the manufacturing cost of the case 13 can be reduced by rolling the spiral groove 28 on the outer periphery of the case 13.

  The air vent passage communicating from the bottom member 17 and the bottom of the bottomed hole 12 to the outside has vertical grooves 29 formed on the inner periphery of the bottomed hole 12 as shown in FIGS. The spline groove 30 may be adopted. Such vertical grooves 29 and spline grooves 30 may be formed by cutting the inner periphery of the bottomed hole 12, but the cost is low when the die is formed by aluminum die casting of the cylinder head 2.

  Further, the air vent passage communicating from the bottom member 17 and the bottom of the bottomed hole 12 to the outside adopts a spiral groove 31 formed on the inner periphery of the bottomed hole 12 as shown in FIG. Also good. The spiral groove 31 can be formed by cutting the inner periphery of the bottomed hole 12.

  FIG. 10 shows a lash adjuster 41 according to the second embodiment of the present invention. As in the first embodiment, the lash adjuster 41 uses an air vent hole 24 at the bottom of the bottomed hole 12 as an air vent passage from the bottomed hole 12. Hereinafter, portions corresponding to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The adjusting screw 16 supports a pivot member 16A inserted into the case 13 so as to be slidable in the axial direction, a male screw member 16B supporting the insertion end of the pivot member 16A into the case 13 and having a male screw 15 on the outer periphery, and a pivot. The disc spring 16C is sandwiched between the member 16A and the male screw member 16B.

  The return spring 18 is a torsion coil spring. The return spring 18 has a lower end locked in a locking hole 42 formed in the bottom member 17 of the case 13, and an upper end locked in a locking hole 43 formed in the male screw member 16B. The rotational force in the direction in which the pivot member 16A protrudes from the case 13 is applied to the male screw member 16B by torsional deformation.

  At the bottom of the bottomed hole 12, an air vent hole 24 that communicates with the outside through the inside of the cylinder head 2 is formed.

  As in the first embodiment, when the lash adjuster 41 is inserted into the bottomed hole 12, the air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged to the outside through the air vent hole 24. Therefore, no reaction force is generated in the bottom member 17, and the time required for completing the insertion is short. Further, even when the air remaining between the bottom member 17 and the bottom of the bottomed hole 12 is thermally expanded during engine operation, the increased air is exhausted to the outside through the air vent hole 24. The case 13 does not float and the operation reliability is high.

  Further, the lash adjuster 41 is provided between the male screw member 16B and the pivot member 16A when the engine is stopped in a high temperature state, and thereafter, when the engine is cooled and a contraction difference is generated between the constituent members of the valve gear. When the disc spring 16C is compressed, the contraction difference 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.

  When a torsion coil spring is used as the return spring 18, the return spring 18 may be a cylinder wound as shown in FIG. 10 or a cone wound as shown in FIG. 11. May be.

  12 and 13 show a lash adjuster 51 according to a third embodiment of the present invention. In this lash adjuster 51, the return spring 18 of the second embodiment is a bamboo spring. Hereinafter, parts corresponding to those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  The external thread 15 on the outer periphery of the external thread member 16B and the internal thread 14 on the inner periphery of the case 13 are vertically symmetrical trapezoidal screws.

  The return spring 18 is a bamboo child spring in which a thin plate material is spirally wound. The return spring 18 has a large-diameter end that is prevented from rotating by the bottom member 17 of the case 13, and a small-diameter end that is inserted into a slit formed in the protrusion 52 at the insertion end of the male screw member 16 </ b> B into the case 13. By the deformation, the rotational force in the direction in which the pivot member 16A protrudes from the case 13 is applied to the male screw member 16B.

  When the lash adjuster 51 is also inserted into the bottomed hole 12, air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged to the outside through the air vent hole 24. There is no reaction force, and the time required to complete the insertion is short. Further, even when the air remaining between the bottom member 17 and the bottom of the bottomed hole 12 is thermally expanded during engine operation, the increased air is exhausted to the outside through the air vent hole 24. The case 13 does not float and the operation reliability is high.

  FIG. 14 shows a lash adjuster 61 according to the fourth embodiment of the present invention. In this lash adjuster 61, the return spring 18 of the second embodiment is a spring. Hereinafter, parts corresponding to those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  The male screw 15 on the outer periphery of the male screw member 16B and the female screw 14 on the inner periphery of the case 13 are vertically symmetrical triangular screws.

  The return spring 18 is a mainspring spring in which a thin plate material is wound in a spiral shape. The return spring 18 has a large-diameter end that is prevented from rotating by the bottom member 17 of the case 13, and a small-diameter end that is inserted into a slit formed in the projection 62 at the insertion end of the male screw member 16B into the case 13, The rotational force in the direction in which the pivot member 16A protrudes from the case 13 is applied to the male screw member 16B by torsional deformation.

  When the lash adjuster 61 is also inserted into the bottomed hole 12, the air between the bottom member 17 and the bottom of the bottomed hole 12 is discharged to the outside through the air vent hole 24. There is no reaction force, and the time required to complete the insertion is short. Further, even when the air remaining between the bottom member 17 and the bottom of the bottomed hole 12 is thermally expanded during engine operation, the increased air is exhausted to the outside through the air vent hole 24. The case 13 does not float and the operation reliability is high.

  In the second to fourth embodiments, similarly to the first embodiment, the longitudinal groove 26 shown in FIG. 4, the spline groove 27 shown in FIG. 5, the spiral groove 28 shown in FIG. A vertical groove 29 shown in FIG. 7, a spline groove 30 shown in FIG. 8, a spiral groove 31 shown in FIG. 9, and the like can be employed.

  In each of the above embodiments, the lash adjuster in which the bottom member 17 is fixed to the lower end of the case 13 has been described as an example. However, in the present invention, the bottom portion that supports the lower end of the return spring 18 is formed integrally with the lower end of the case 13. It can also be applied to lash adjusters.

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 process in which a lash adjuster is inserted in the bottomed hole of the cylinder head shown in FIG. The expanded sectional view which shows the modification which replaced the air vent hole shown in FIG. 2 with the vertical groove | channel of the outer periphery of a case FIG. 2 is an enlarged sectional view showing a modification in which the air vent hole shown in FIG. 2 is replaced with a spline groove on the outer periphery of the case. The expanded sectional view which shows the modification which replaced the air vent hole shown in FIG. 2 with the spiral groove of the outer periphery of a case The expanded sectional view which shows the modification which replaced the air vent hole shown in FIG. 2 with the vertical groove of the inner periphery of a bottomed hole 2 is an enlarged cross-sectional view showing a modification in which the air vent hole shown in FIG. 2 is replaced with a spline groove on the inner periphery of the bottomed hole. The expanded sectional view which shows the modification which replaced the air vent hole shown in FIG. 2 with the spiral groove of the inner periphery of a bottomed hole The expanded sectional view which shows the lash adjuster of 2nd Embodiment of this invention FIG. 10 is an enlarged sectional view showing a modification of the lash adjuster shown in FIG. The expanded sectional view which shows the lash adjuster of 3rd Embodiment of this invention Sectional view along line XIII-XIII in FIG. The expanded sectional view which shows the lash adjuster of 4th Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rush adjuster 2 Cylinder head 12 Bottomed hole 13 Case 14 Female screw 15 Male screw 16 Adjusting screw 16A Pivot member 16B Male screw member 16C Belleville spring 17 Bottom member 18 Return spring 24 Air vent hole 25 Oil hole 26 Vertical groove 27 Spline groove 28 Spiral Groove 29 Vertical groove 30 Spline groove 31 Spiral groove 41, 51, 61 Rush adjuster

Claims (13)

  A cylindrical case (13) inserted into a bottomed hole (12) opened in the upper surface of the cylinder head (2) and a female screw (14) formed on the inner periphery of the case (13) are screw-engaged. An adjustment screw (16) having a male screw (15) on the outer periphery, and an insertion end of the adjustment screw (16) into the case (13) and a bottom portion (17) provided at the lower end of the case (13) A lash adjuster for biasing the adjustment screw (16) in a direction protruding upward from the case (13) by the return spring (18). A lash adjuster comprising an air vent passage (24) communicating from the bottom (17) and the bottom of the bottomed hole (12) to the outside.   The lash adjuster according to claim 1, wherein the air vent passage is an air vent hole (24) formed in a bottom of the bottomed hole (12).   The oil passage hole (25) which penetrates the bottom part (17) of the said case (13) up and down is provided, and the lower end of the oil passage hole (25) is connected to the said air vent hole (24). Rush adjuster.   The lash adjuster according to claim 1, wherein the air vent passage is a longitudinal groove (26) formed on an outer periphery of the case (13).   The lash adjuster according to claim 1, wherein the air vent passage is a spline groove (27) formed on an outer periphery of the case (13).   The lash adjuster according to claim 1, wherein the air vent passage is a spiral groove (28) formed on an outer periphery of the case (13).   The lash adjuster according to claim 1, wherein the air vent passage is a longitudinal groove (29) formed in an inner periphery of the bottomed hole (12).   The lash adjuster according to claim 1, wherein the air vent passage is a spline groove (30) formed in an inner periphery of the bottomed hole (12).   The lash adjuster according to claim 1, wherein the air vent passage is a spiral groove (31) formed in an inner periphery of the bottomed hole (12).   The lash adjuster according to any one of claims 1 to 9, wherein the return spring (18) is a compression coil spring that applies an axial force in a direction protruding from the case (13) to the adjustment screw (16).   The lash adjuster according to any one of claims 1 to 9, wherein the return spring (18) is a torsion spring that applies a rotational force in a direction protruding from the case (13) to the adjustment screw (16).   The lash adjuster according to claim 11, wherein the torsion spring is one of a torsion coil spring, a spring, and a bamboo spring.   The lash adjuster according to any one of claims 1 to 12, wherein the male screw (15) and the female screw (14) are triangular screws, trapezoidal screws, or sawtooth screws.

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