JP2009270497A - Lash adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lash adjuster superior in productivity of a nut member, and reducing the number of part items. <P>SOLUTION: This lash adjuster of a valve gear includes the nut member 14, an adjusting screw 17 having on the outer periphery a male screw 16 engaging by a screw with a female screw 15 of its nut member 14, and a coil spring 18 for urging the adjusting screw 17 in the direction for projecting from the nut member 14, and is provided so that the male screw 16 and the female screw 15 are formed in a sawtooth shape larger than a flank angle of a play side flank 20 in a flank angle of a pressure side flank 19 for receiving pressure when a load is applied in the direction for pushing the adjusting screw 17 in the nut member 14. The nut member 14 is molded in a pipe shape of opening both ends, and the coil spring 18 is supported by an inner peripheral screw groove 21 of 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 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. One end of the arm that is pushed down (swing arm type valve operating device) or the arm supported so as to be able to swing with the center as a fulcrum is pushed up with a cam, and the valve stem is pushed down at the other end of the arm A thing (rocker arm type valve gear) is known.

  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 clearance.

  In order to prevent this abnormal noise and compression leakage, a lash adjuster is incorporated in the valve operating device, and the lash adjuster often absorbs a change in a gap between the 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 adjustment screw having a male screw on the outer periphery, and a coil spring incorporated in the nut member and biasing the adjustment screw in a direction protruding upward from the nut member, and a protruding end of the adjustment screw from the nut member A device that supports the arm of the valve gear so as to be swingable is known (Patent Document 1).

  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 coil spring that is incorporated in the nut member and biases the adjusting screw in a direction protruding downward from the nut member, from the nut member of the adjusting screw. A device that presses a valve stem of a valve operating device at a protruding end is known (Patent Document 2).

  In these lash adjusters, the male screw of the adjusting screw and the female screw of the nut member are the pressure side flank that receives pressure when a load in the direction in which the adjusting screw is pushed into the nut member (hereinafter referred to as the “pushing direction”) is applied. The flank angle is formed in a sawtooth shape larger than the flank angle of the play side flank, and when a static load in the push-in direction is applied to the adjustment screw, it is adjusted by the frictional resistance between the pressure side flank of the male screw and the female screw. When the screw is prevented from rotating and, on the other hand, when a static load in the protruding direction is applied to the adjusting screw, the adjusting screw is allowed to rotate by sliding between the play side flank of the male screw and the female screw.

  Therefore, when a load in the pushing direction is applied to the adjustment screw due to the rotation of the cam, the pressure side flank of the male screw is received by the pressure side flank of the female screw, and the axial position of the adjustment 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 by the load in the protruding direction loaded from the coil 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 gradually moves in the push-in direction to absorb the change in the gap between the constituent members of the valve gear.
JP 2005-273510 A JP 2006-132426 A

  Incidentally, in the lash adjuster described in Patent Document 1, since the nut member is integrally formed in a bottomed cylindrical shape, the tip end of the tap does not interfere with the bottom of the nut member when the female screw of the nut member is processed with the tap. It is necessary to process within the range. Therefore, the feed of the tapping process cannot be made fast, and the productivity of the nut member is low.

  On the other hand, in the lash adjuster described in Patent Document 2, both ends of the nut member are open, and a spring seat that supports the coil spring is fixed to one end of the nut member. Since this lash adjuster has both ends of the nut member open, when tapping the internal thread of the inner periphery of the nut member, there is nothing that interferes with the tip of the tap, and the tapping feed can be made faster. .

  However, in the lash adjuster described in Patent Document 2, since the spring seat for supporting the coil spring is provided separately from the nut member, the coil spring is supported by the bottom of the nut member integrally formed into a bottomed cylindrical shape. Compared with the lash adjuster (the one described in Patent Document 1), the number of parts is large and the management of the parts is complicated.

  In the lash adjuster described in Patent Document 1, the nut member is integrally formed in a bottomed cylindrical shape. For this reason, when the coil spring is inserted into the nut member when assembling the lash adjuster, the coil spring becomes deep and difficult to see, and it is difficult to check whether the coil spring has been inserted to the back without being caught.

  Moreover, the nut member of each lash adjuster mentioned above has a female thread only in the part which contacts an adjustment screw among the full length, and tapping of the female thread is performed for every individual nut member. Here, if tapping of a plurality of nut members can be performed at once, the productivity of the nut members can be further increased, but such a lash adjuster has not been known yet.

  The problem to be solved by the present invention is to provide a lash adjuster having excellent nut member productivity and a small number of parts.

  In order to solve the above problems, the nut member is formed into a pipe shape with both ends open, and the coil spring is supported by a support groove formed on the inner periphery of the nut member.

  If it does in this way, since the both ends of a nut member are open | released, when tapping the internal thread of the inner periphery of a nut member, there is nothing which interferes with the front-end | tip of a tap. Therefore, the feed of tapping can be made faster, and the productivity of the nut member is high. Further, since the coil spring is supported by the support groove formed on the inner periphery of the nut member, it is not necessary to provide a spring seat supporting the coil spring separately from the nut member, and the number of parts is small.

  Further, since both ends of the nut member are open, when assembling the lash adjuster, the adjustment screw can be screwed from one end of the nut member, and then the coil spring can be inserted from the other end of the nut member. Therefore, the coil spring inserted into the nut member can be easily seen, and the lash adjuster can be easily assembled.

  The female screw can be formed over the entire length of the nut member, and the screw groove of the female screw can be used as the support groove. If it does in this way, after tapping a female screw in the inner periphery of the pipe material of the length equivalent to a plurality of nut members, each nut member can be produced by cutting the pipe material. Therefore, tapping for a plurality of nut members can be performed at once, and the productivity of the nut members is high.

  When using the female groove as the support groove, the winding direction of the coil spring is the same as the winding direction of the female screw, and the end of the coil spring is screwed into the screw groove of the female screw with a tightening margin, and the screwing Thus, the coil spring can be supported. In this way, the end of the coil spring contacts the thread groove along the spiral of the female thread, so that the contact length of the end of the coil spring with respect to the thread groove can be increased, and the posture of the coil spring is stable. To do.

  Further, when the thread groove of the female screw is used as a support groove, the winding direction of the coil spring is opposite to the winding direction of the female screw, and the end of the coil spring is engaged with the thread groove of the female screw with a tightening margin, The coil spring can be supported by the engagement. In this case, since the winding direction of the coil spring and the winding direction of the female screw are opposite directions, it is possible to prevent the coil spring from rotating with respect to the nut member when an axial load is applied to the coil spring. It is possible to stabilize the axial position of the coil spring.

  Further, a circumferential groove formed on the inner periphery of the nut member is used as the support groove, and the end of the coil spring is fitted into the circumferential groove, and the coil spring is supported by the fitting. You can also

Each said structure is employable as the following lash adjuster, for example.
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 inserted into a receiving hole opened on the lower surface of the arm that swings according to the rotation of the cam, and the adjusting screw presses the valve stem of the valve operating device at the protruding end from the nut member. Rush adjuster for rocker arm type valve gear.

  In the lash adjuster according to the present invention, since both ends of the nut member are open, when tapping the internal thread of the inner periphery of the nut member, the feed of the tapping process can be made fast, and the productivity of the nut member is high. . Further, since the coil spring is supported by the support groove formed on the inner periphery of the nut member, it is not necessary to provide a spring seat supporting the coil spring separately from the nut member, and the number of parts is small.

  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. 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 is screwed into a nut member 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 nut member 14. An adjustment screw 17 having a male screw 16 to be fitted on the outer periphery of the lower part and a coil spring 18 incorporated in the nut member 14 are provided.

  As shown in FIG. 2, the nut member 14 is formed in a pipe shape with both ends open, and the female screw 15 is formed over the entire length of the nut member 14. The nut member 14 can be produced by tapping a female screw 15 on the inner periphery of an iron pipe member having a length corresponding to a plurality of nut members 14 and then cutting the pipe member.

  The male screw 16 and the female screw 15 have a sawtooth shape in which the flank angle of the pressure-side flank 19 that receives pressure when a load in the direction of pushing the adjusting screw 17 into the nut member 14 is applied is larger than the flank angle of the play-side flank 20. When the static load in the pushing direction is applied to the adjustment screw 17, the rotation of the adjustment screw 17 is prevented by the frictional resistance between the pressure side flank 19, 19 of the male screw 16 and the female screw 15, When a static load in the protruding direction is applied to the adjustment screw 17, the adjustment screw 17 is allowed to rotate by sliding between the play side flank 20, 20 of the male screw 16 and the female screw 15. As the male screw 16 and the female screw 15, for example, those having a flank angle of the pressure side flank 19 of 75 ° and a flank angle of the play side flank 20 of 15 ° can be employed.

  The coil spring 18 is formed by winding a metal wire in the same direction as the winding direction of the female screw 15 and is coaxially incorporated in the nut member 14. The coil spring 18 is formed such that an end portion 18A opposite to the adjustment screw 17 side is formed in a spiral shape having a diameter larger than the diameter of the valley of the female screw 15, and the end portion 18A of the female screw 15 is formed. The screw groove 21 is screwed with a tightening margin. Here, the coil spring 18 is supported by the screw groove 21 by screwing the end 18A. Further, the end of the coil spring 18 on the side of the adjusting screw 17 presses the adjusting screw 17 via the spring seat 22, and the pressing force biases the adjusting screw 17 in a direction protruding upward from the nut member 14. is doing.

  As shown in FIG. 1, the adjusting screw 17 has a hemispherical protruding end 23 from the nut member 14, and the protruding end 23 fits into a recess 24 formed on the lower surface of the end of the arm 7. is doing. Here, the projecting end 23 is slidably in contact with the inner surface of the recess 24 and supports the arm 7 so as to be swingable by the sliding.

  An oil drain hole 25 communicating with the outside is formed on the inner bottom surface of the accommodation hole 13. Therefore, the lubricating oil that has flowed into the nut member 14 from the upper end surface of the nut member 14 through the gap between the male screw 16 and the female screw 15 is discharged from the lower end of the nut member 14 through the oil drain hole 25.

  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 adjusting screw 17, but the pressure side flank 19 of the male screw 16 is received by the pressure side flank 19 of the female screw 15, and the axial position of the adjusting 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 flank 19, 19 of the male screw 16 and the female screw 15, and the adjustment screw 17 moves in the pushing direction by the slip. However, when the cam crest 6b passes the position of the roller 11 and the load in the pushing direction is released, the adjustment screw 17 moves in the protruding direction due to the load in the protruding direction loaded from the coil spring 18. Return 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 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, each time the cam 6 rotates, the adjustment screw 17 gradually moves 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 this lash adjuster 1, since both ends of the nut member 14 are open, there is nothing that interferes with the tip of the tap when the female screw 15 is tapped. Therefore, the feed of tapping can be made faster, and the productivity of the nut member 14 is high.

  Further, since the lash adjuster 1 has the female screw 15 over the entire length of the nut member 14, after tapping the female screw 15 on the inner periphery of the pipe material having a length corresponding to a plurality of nut members 14, the pipe material By cutting the nut member 14, the nut member 14 can be produced. Therefore, the lash adjuster 1 can perform tapping for a plurality of nut members 14 at a time, and the productivity of the nut members 14 is high.

  Further, since the lash adjuster 1 supports the coil spring 18 with the thread groove 21 formed on the inner periphery of the nut member 14, it is not necessary to provide a spring seat for supporting the coil spring 18 separately from the nut member 14. The number of parts is small.

  Since the lash adjuster 1 has both ends of the nut member 14 open, when assembling the lash adjuster 1, the adjustment screw 17 is screwed from one end of the nut member 14, and then the coil is started from the other end of the nut member 14. A spring 18 can be inserted. Therefore, the coil spring 18 inserted into the nut member 14 can be easily seen, and the lash adjuster 1 can be easily assembled.

  Further, in this lash adjuster 1, since the end 18A of the coil spring 18 is in contact with the screw groove 21 along the spiral of the female screw 15, the contact length of the end 18A with respect to the screw groove 21 is long. 18 postures are stable.

  As shown in FIG. 3, the coil spring 18 has a winding direction opposite to the winding direction of the female screw 15, and an end 18 B of the coil spring 18 opposite to the adjustment screw 17 side is a thread groove 21 of the female screw 15. It is also possible to engage with the screw groove 21 and to support the screw groove 21 by the engagement. In this way, since the winding direction of the coil spring 18 and the winding direction of the female screw 15 are opposite directions, the coil spring 18 rotates relative to the nut member 14 when an axial load is applied to the coil spring 18. The axial position of the coil spring 18 is stabilized.

  In the above embodiment, the thread groove 21 of the female screw 15 is used as a support groove for supporting the coil spring 18. However, as shown in FIGS. 4 and 5, the coil is formed by the circumferential groove 26 formed on the inner periphery of the nut member 14. The spring 18 may be supported. Here, the coil spring 18 is formed such that an end portion 18C opposite to the adjustment screw 17 is formed in an arc shape having a diameter larger than the diameter of the valley of the female screw 15, and the end portion thereof is a circumferential groove 26. Is fitted.

  FIG. 6 shows a valve gear incorporating a lash adjuster 31 according to the second embodiment of the present invention. As in the above embodiment, this valve operating device swings in response to the rotation of the valve 34 provided in the intake port 33 of the cylinder head 32 of the engine, the valve stem 35 connected to the valve 34, and the cam 36. And an arm 37.

  The valve stem 35 extends upward from the valve 34, and a spring retainer 38 is fixed to the upper portion of the valve stem 35. The spring retainer 38 is urged upward by a valve spring 39, and the valve 34 is seated on the valve seat 40 by the urging force.

  The center of the arm 37 is supported by a fulcrum shaft 41 so as to be swingable. A roller 42 that contacts the cam 36 is attached to one end of the arm 37, and a lash adjuster 31 is incorporated into the other end of the arm 37. The cam 36 provided below the arm 37 is integrally formed with a camshaft 43 that rotates in synchronization with a crankshaft (not shown) of the engine. When the camshaft 43 rotates, the cam 36 rotates relative to the base circle 36a. The cam crest portion 36 b that is raised in this manner presses the roller 42 and swings the arm 37.

  As shown in FIGS. 6 and 7, the lash adjuster 31 is screw-engaged with a nut member 45 inserted into the accommodation hole 44 opened on the lower surface of the arm 37 and a female screw 46 formed on the inner periphery of the nut member 45. An adjustment screw 48 having a male screw 47 on the outer periphery thereof, and a coil spring 49 incorporated in the nut member 45.

  As shown in FIG. 7, the nut member 45 is formed in a pipe shape whose both ends are open, and the female screw 46 is formed over the entire length of the nut member 45. The nut member 45 can be produced by tapping a female thread 46 on the inner periphery of an iron pipe member having a length corresponding to a plurality of nut members 45 and then cutting the pipe member.

  The male screw 47 and the female screw 46 have a sawtooth shape in which the flank angle of the pressure side flank 50 that receives pressure when a load in the direction of pushing the adjusting screw 48 into the nut member 45 is applied is larger than the flank angle of the play side flank 51. When the static load in the pushing direction is applied to the adjusting screw 48, rotation of the adjusting screw 48 is prevented by the frictional resistance between the pressure side flank 50, 50 of the male screw 47 and the female screw 46, When a static load in the protruding direction is applied to the adjusting screw 48, the adjusting screw 48 is allowed to rotate by sliding between the play side flanks 51, 51 of the male screw 47 and the female screw 46.

  The coil spring 49 is formed by winding a metal wire in the same direction as the winding direction of the female screw 46 and is coaxially incorporated in the nut member 45. Further, the coil spring 49 is formed such that an end portion 49 </ b> A opposite to the adjustment screw 48 side has a spiral shape having a diameter larger than the diameter of the valley of the female screw 46, and the end portion 49 </ b> A is formed of the female screw 46. The thread groove 52 is screwed with a tightening margin. Here, the coil spring 49 is supported by the screw groove 52 by screwing of the end portion 49A. Further, the end of the coil spring 49 on the side of the adjusting screw 48 presses the adjusting screw 48 via the spring seat 53, and the pressing force biases the adjusting screw 48 in a direction protruding downward from the nut member 45. is doing. In the adjusting screw 48, the protruding end from the nut member 45 presses the upper end of the valve stem 35 (see FIG. 6).

  As shown in FIG. 6, the arm 37 is formed with an oil passage hole 54 that communicates from the upper surface to the inner bottom surface of the accommodation hole 44. Therefore, the lubricating oil splashed on the arm 37 is introduced into the nut member 45 through the oil passage hole 54. The lubricating oil introduced into the nut member 45 lubricates the male screw 47 and the female screw 46.

  As in the first embodiment, the lash adjuster 31 is configured such that when the cam crest portion 36b of the cam 36 pushes up the end of the arm 37 and a load in the pushing direction is applied to the adjusting screw 48, the pressure side flank of the male screw 47 is pressed. 50 is received by the pressure side flank 50 of the female screw 46, and the axial position of the adjusting screw 48 with respect to the nut member 45 is fixed. At this time, strictly speaking, a slight slip occurs between the pressure side flank 50, 50 of the male screw 47 and the female screw 46, and the adjustment screw 48 moves in the pushing direction due to the sliding, but the cam 36 further rotates to push the pushing direction. When the load is released, the adjustment screw 48 moves in the protruding direction by the load in the protruding direction applied from the coil spring 49, and returns to the original position.

  Since the lash adjuster 31 is open at both ends of the nut member 45, there is nothing that interferes with the tip of the tap when the female screw 46 is tapped. Therefore, the feed of tapping can be speeded up, and the productivity of the nut member 45 is high.

  In addition, since the lash adjuster 31 has a female thread 46 over the entire length of the nut member 45, the pipe material is formed after tapping the female thread 46 on the inner periphery of a pipe material having a length corresponding to a plurality of nut members 45. The nut member 45 can be produced by cutting. Therefore, the lash adjuster 31 can perform tapping for a plurality of nut members 45 at a time, and the productivity of the nut members 45 is high.

  Further, since the lash adjuster 31 supports the coil spring 49 by the thread groove 52 formed on the inner periphery of the nut member 45, it is not necessary to provide a spring seat for supporting the coil spring 49 separately from the nut member 45. The number of parts is small.

  Since the lash adjuster 31 is open at both ends of the nut member 45, when the lash adjuster 31 is assembled, the adjustment screw 48 is screwed from one end of the nut member 45, and then the coil from the other end of the nut member 45. A spring 49 can be inserted. Therefore, the coil spring 49 inserted into the nut member 45 is easy to see, and the assembly work of the lash adjuster 31 is easy.

  Further, in this lash adjuster 31, since the end portion 49A of the coil spring 49 is in contact with the screw groove 52 along the spiral of the female screw 46, the contact length of the end portion 49A with respect to the screw groove 52 is long. 49 posture is stable.

  As shown in FIG. 8, the coil spring 49 has its winding direction opposite to the winding direction of the female screw 46, and the end portion 49B of the coil spring 49 is engaged with the thread groove 52 of the female screw 46 with a tightening margin. You may make it be supported by the thread groove 52 by engagement. In this way, the winding direction of the coil spring 49 and the winding direction of the female screw 46 are opposite directions, so that when the axial load is applied to the coil spring 49, the coil spring 49 rotates with respect to the nut member 45. The axial position of the coil spring 49 is stabilized.

  In this embodiment, the thread groove 52 of the female thread 46 is used as a support groove for supporting the coil spring 49. However, instead of the thread groove 52, a circumferential groove as shown in FIGS. .

The front view which shows the valve operating apparatus incorporating the lash adjuster of 1st Embodiment of this invention Enlarged sectional view of the lash adjuster shown in FIG. Enlarged sectional view showing a modification of the lash adjuster shown in FIG. FIG. 1 is an enlarged sectional view showing another modification of the lash adjuster shown in FIG. Sectional view along line VV in FIG. The front view which shows the valve operating apparatus incorporating the lash adjuster of 2nd Embodiment of this invention. Enlarged sectional view of the lash adjuster shown in FIG. Enlarged sectional view showing a modification of the lash adjuster shown in FIG.

Explanation of symbols

1 Rush Adjuster 2 Cylinder Head 7 Arm 13 Receiving Hole 14 Nut Member 15 Female Thread 16 Male Thread 17 Adjusting Screw 18 Coil Spring 18A, 18B, 18C End of Coil Spring 19 Pressure Side Flank 20 Play Side Flank 21 Screw Groove 23 Projecting End 26 Circle Circumferential groove 31 Rush adjuster 35 Valve stem 36 Cam 37 Arm 44 Receiving hole 45 Nut member 46 Female thread 47 Male thread 48 Adjusting screw 49 Coil springs 49A and 49B Coil spring end 50 Pressure side flank 51 Play side flank 52 Screw groove

Claims (7)

A nut member (14) having an internal thread (15) on the inner periphery, an adjustment screw (17) having an external thread (16) on the outer periphery that engages with the female thread (15) of the nut member (14), and the nut member (14) and a coil spring (18) that urges the adjustment screw (17) in a direction protruding from the nut member (14), and the male screw (16) and the female screw (15) are adjusted. A sawtooth shape in which the flank angle of the pressure side flank (19) that receives pressure when a load in the direction of pushing the screw (17) into the nut member (14) is applied is larger than the flank angle of the play side flank (20). In the lash adjuster of the valve gear formed in
The nut member (14) is formed into a pipe shape with both ends open, and the coil spring (18) is supported by a support groove (21) formed on the inner periphery of the nut member (14). Rush adjuster to do.   The lash adjuster according to claim 1, wherein the female screw (15) is formed over the entire length of the nut member (14), and a screw groove (21) of the female screw (15) is used as the support groove.   The winding direction of the coil spring (18) is the same as the winding direction of the female screw (15), and the end (18A) of the coil spring (18) is tightened to the thread groove (21) of the female screw (15). The lash adjuster according to claim 2, wherein the coil spring (18) is supported by screwing.   The winding direction of the coil spring (18) is opposite to the winding direction of the female screw (15), and the end (18B) of the coil spring (18) is fastened to the thread groove (21) of the female screw (15). The lash adjuster according to claim 2, wherein the coil spring (18) is supported by the engagement.   The support groove is a circumferential groove (26) formed on the inner circumference of the nut member (14), and the end (18C) of the coil spring (18) is fitted into the circumferential groove (26). The lash adjuster according to claim 1, wherein the coil spring (18) is supported by the fitting.   The nut member (14) is inserted into a receiving hole (13) opened in the upper surface of the cylinder head (2), and the adjustment screw (17) is moved by a protruding end (23) from the nut member (14). The lash adjuster according to any one of claims 1 to 5, wherein the arm (7) of the valve device is swingably supported.   The nut member (45) is inserted into a receiving hole (44) opened in the lower surface of an arm (37) that swings in response to rotation of the cam (36), and the adjustment screw (48) The lash adjuster according to any one of claims 1 to 5, wherein a valve stem (35) of the valve gear is pressed by a protruding end from 45).

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