JP2013234592A - Valve lift adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve lift adjusting device which can suppress the breakage of an operation member and the erroneous operation of a slider.SOLUTION: A slider 20 is formed with: a first protrusion 32 which protrudes to a radial outside direction rather than a radial external face 21 of the slider 20 at a position opposite to a rotation direction with respect to a first inclined face 26 of a first engagement groove 22, and can push back an operation pin 41 push backed to the radial outside direction by the first inclined face 26 to further radial outside direction; and a second protrusion 34 which protrudes to the radial outside direction rather than the radial external face 21 of the slider 20 at a position opposite to a rotation direction with respect to a second inclined face 31 of a second engagement groove 27, and can push back the operation pin 41 which is pushed back by the first inclined face 26 to the radial outside direction to a further radial outside direction. Accordingly, since the operation pin 41 does not contact with the first engagement groove 22 and the second engagement groove 27 even if the operation pin slightly protrudes to a radial inside direction by an influence of wobbling at attachment, the breakage of the operation pin 41 and the erroneous operation of the slider 20 can be suppressed.

Description

  The present invention relates to a valve lift adjusting device.

  2. Description of the Related Art There is known a valve lift adjusting device that includes two cams that can convert the rotational movement of a cam shaft of an internal combustion engine into a reciprocating linear movement of an engine valve, and adjusts the valve lift by switching the cam that interlocks the engine valve. The valve lift adjusting device disclosed in Patent Document 1 performs cam switching by a slider. The slider is a cylindrical member that moves in the axial direction integrally with each cam, and has a first engagement groove and a second engagement groove extending in the rotation direction. The first engagement groove and the second engagement groove have a slope whose depth from the outer surface of the slider becomes shallower in the direction opposite to the rotation direction. The inclined surface pushes back the operation member of the actuator inserted in each engagement groove in the radially outward direction when the slider is rotating.

US Patent Application Publication No. 2011/0247577

  In the valve lift adjusting device disclosed in Patent Document 1, the slope of the engagement groove pushes back the operating member of the actuator only to the outer surface of the slider. Therefore, in the case of an actuator that returns only to the point where the operating member is pressed, the slider rotates while the tip end surface of the operating member slides on the outer surface of the slider, and there is a concern about wear of the operating member and the slider. Is done. In addition, when the operating member protrudes in the radially inward direction from the radially outer surface due to the influence of the mounting play after being pushed back by the inclined surface, the operating member is damaged due to the tip portion of the operating member coming into contact with the engaging groove. Or the slider may malfunction.

  The present invention has been made in view of the above-described points, and an object thereof is to provide a valve lift adjusting device capable of suppressing breakage of an operation member and malfunction of a slider.

  The present invention is a valve lift adjusting device capable of changing a valve lift of an engine valve, wherein the slider forms a first protrusion and a second protrusion. The first protrusion protrudes radially outward from the radially outer surface of the slider at a position opposite to the rotational direction with respect to the first slope of the first engagement groove, and the operating member pushed back radially outward by the first slope. Further, it can be pushed back in the radially outward direction. The second protrusion protrudes radially outward from the radially outer surface of the slider at a position opposite to the rotational direction with respect to the second slope of the second engagement groove, and the operation member pushed back radially outward by the first slope. Further, it can be pushed back in the radially outward direction.

Therefore, the operating member is pushed back in the radially outward direction from the radially outer surface of the slider by each protrusion, so that even if the operating member protrudes slightly inwardly due to the mounting backlash, it contacts the first engaging groove and the second engaging groove. do not do. Therefore, according to the present invention, it is possible to suppress damage to the operation member and malfunction of the slider due to the tip portion of the operation member coming into contact with the engagement groove.
In addition, it is possible to allow the operation member to be attached by the amount of protrusion of the first protrusion and the second protrusion in the radially outward direction. For this reason, the operation member and the member to which the operation member is attached do not require high dimensional accuracy, so that the manufacturing cost can be reduced.

Here, when the operating member is pushed back only to the outer surface of the slider, the operating member is inserted into the engaging groove immediately after the operation having a relatively slow operating speed, so that the slider particularly rotates at a high speed. In addition, it is difficult to control the operation of the operating member.
On the other hand, according to the present invention, the operation member starts operation from a position away from the outer surface of the slider, and is inserted into the engagement groove when it is accelerated to some extent. Therefore, the operation control of the operation member is facilitated, and the operation member can be reliably inserted into the engagement groove.

1 is a diagram illustrating a schematic configuration of a valve system to which a valve lift adjusting device according to a first embodiment of the present invention is applied. It is the II-II sectional view taken on the line of FIG. It is sectional drawing which passes along the 1st engaging groove and 2nd engaging groove of the slider of FIG. It is a figure which shows the valve system seen from the arrow IV direction of FIG. It is the perspective view which looked at the slider of FIG. 1 from the 1st protrusion side. It is a figure which shows the state which the operation pin protruded to the slider side from the state shown in FIG. 1 inserted in the 1st engagement groove | channel. It is sectional drawing which shows the place where the slider rotated from the state shown in FIG. 3, and the operation pin was pushed back to the position which corresponds to the radial outer surface of a slider. FIG. 8 is a cross-sectional view showing a state where the slider is further rotated from the state shown in FIG. 7 and the operation pin is pushed back further in the radially outward direction than the radially outer surface of the slider. It is a figure which shows the state which the slider moved to the 2nd operation position from the state shown in FIG. It is a figure which shows the state which the operation pin protruded to the slider side from the state shown in FIG. 9 inserted in the 2nd engagement groove. It is a figure which shows schematic structure of the valve system to which the valve lift adjustment apparatus by 2nd Embodiment of this invention was applied. It is sectional drawing which passes along the 1st engaging groove and 2nd engaging groove of the slider of FIG. It is a figure which shows the valve system seen from the arrow XIII direction of FIG.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
The valve lift adjusting device according to the first embodiment of the present invention is a variable valve mechanism of a cam switching type and is used in the valve system shown in FIG. The valve system 90 is a system that opens and closes an intake valve 91 of the internal combustion engine. The camshaft 92 is rotatably supported by a cylinder head 93 at a location not shown, and is connected to a crankshaft not shown via a timing chain or the like. The intake valve 91 corresponds to an “engine valve” recited in the claims.

As shown in FIGS. 1 to 4, the valve lift adjusting device 10 includes a low rotation cam 11, a high rotation cam 15, a slider 20, and an actuator 40. The low rotation cam 11 corresponds to a “first cam” described in the claims, and the high rotation cam 15 corresponds to a “second cam” described in the claims.
The low rotation cam 11, the high rotation cam 15 and the slider 20 are made of the same member and are integrally formed with each other.

  The low-rotation cam 11 is a disc cam that is spline-fitted to the cam shaft 92, can transmit rotation to the cam shaft 92, and can relatively move in the axial direction. A cam lobe 13 that protrudes from the base circle 12 in a radially outward direction by a predetermined amount is formed on the radially outer wall of the low-rotation cam 11. The low-rotation cam 11 and the roller rocker 94 constitute a low-rotation cam mechanism that converts the rotational motion of the cam shaft 92 into the reciprocating linear motion of the intake valve 91. In the low-rotation cam mechanism, the low-rotation cam 11 functions as an original node, and the roller rocker 94 functions as a follower.

  The high rotation cam 15 is a disc cam that is spline-fitted to the cam shaft 92 at a position adjacent to one of the low rotation cams 11 in the axial direction. It is movable. A cam lobe 17 that protrudes from the base circle 16 in a radially outward direction is formed on the radially outer wall of the high-rotation cam 15. The base circle 12 and the base circle 16 are formed in the same plane with no step. The high-rotation cam 15 and the roller rocker 94 constitute a high-rotation cam mechanism that converts the rotational motion of the cam shaft 92 into the reciprocating linear motion of the intake valve 91. In the high rotation cam mechanism, the high rotation cam 15 functions as an original node, and the roller rocker 94 functions as a follower.

  The cam profile of the high rotation cam 15 is different from the cam profile of the low rotation cam 11. For example, the maximum cam lift of the high rotation cam 15 is larger than the maximum cam lift of the low rotation cam 11. The cam operating angle of the high-rotation cam 15 is larger than the cam operating angle of the low-rotation cam 11.

  The slider 20 is a cylindrical member that is spline-fitted to the cam shaft 92 at a position adjacent to the other of the low-rotation cam 11 in the axial direction, and can transmit rotation to the cam shaft 92 and can move relative to the axial direction. is there. The slider 20 includes a low rotation cam 11 and a low rotation cam 11 between a first operation position where the low rotation cam 11 contacts the roller rocker 94 and a second operation position where the high rotation cam 15 contacts the roller rocker 94. It can move integrally with the high-rotation cam 15.

The slider 20 has a first engagement groove 22 extending in the rotation direction and a second engagement groove 27 extending in the rotation direction so that the circumferential position does not overlap the first engagement groove 22. Hereinafter, the direction opposite to the rotation direction is referred to as “opposite direction”.
The first engagement groove 22 is opposite to the first circumferential groove 23 and the first circumferential groove 23 whose axial position coincides with an operation pin 41 described later when the slider 20 is located at the first operating position. It is comprised from the 1st inclination groove part 24 which inclines so that it may be located in one direction of an axial direction, so that it may be located in a direction and may go to an opposite direction. The other first inner wall 25 in the axial direction among the inner walls of the first inclined groove portion 24 is inclined so as to be positioned in one of the axial directions as it goes in the opposite direction. Further, the bottom surface of the first inclined groove portion 24 has a first slope 26 whose depth from the outer diameter surface 21 of the slider 20 becomes shallower in the opposite direction.

  The second engagement groove 27 has a second circumferential groove 28 whose axial position coincides with the operation pin 41 when the slider 20 is in the second operating position, and is opposite to the second circumferential groove 28. It is comprised from the 2nd inclination groove part 29 which inclines so that it may be located and may be located in the other of an axial direction, so that it goes to the opposite direction. The other second inner wall 30 in the axial direction among the inner walls of the second inclined groove portion 29 is inclined so as to be positioned in the other axial direction as it goes in the opposite direction. Further, the bottom surface of the second inclined groove portion 29 has a second inclined surface 31 in which the depth from the outer diameter surface 21 of the slider 20 becomes shallower in the opposite direction.

  The actuator 40 is an electromagnetic actuator and includes an operation pin 41 and a drive unit 42. The operation pin 41 corresponds to an “operation member” recited in the claims, and can be moved toward and away from the slider 20 from the radially outward direction. The axial groove widths of the first engagement groove 22 and the second engagement groove 27 are slightly larger than the outer diameter of the distal end portion of the operation pin 41. The distal end portion of the operation pin 41 can be inserted into the first engagement groove 22 and the second engagement groove 27. When the operation pin 41 is inserted into the first engagement groove 22 when the slider 20 is rotating, the operation pin 41 engages with the first inner wall 25 to move the slider 20 to the second operating position, and the slider 20 rotates. When it is inserted into the second engagement groove 27, it engages with the second inner wall 30 to move the slider 20 to the first operating position.

  The drive unit 42 includes a sleeve 43 that is fixed to the cylinder head 93 and supports the operation pin 41, a fixed core 44 that is fixed in the sleeve 43, and a movable core that is fixed to the end of the operation pin 41 in the sleeve 43. 45 and a coil 46 made of a winding wound around the fixed core 44 and generating a magnetic field when energized. The movable core 45 includes a permanent magnet that repels the fixed core 44 that is magnetized by the magnetic field of the coil 46. The drive unit 42 drives the operation pin 41 to the slider 20 side by energizing the coil 46 and separating the movable core 45 from the fixed core 44.

When the drive unit 42 moves the slider 20 from the first operation position to the second operation position, when the circumferential position of the operation pin 41 coincides with the first engagement groove 22, the operation pin 41 is changed to the first engagement groove 22. When the operation for insertion is started and the circumferential position of the operation pin 41 coincides with the first slope 26, the energization is stopped.
When the drive unit 42 moves the slider 20 from the second operation position to the first operation position, when the circumferential position of the operation pin 41 coincides with the second engagement groove 27, the operation pin 41 is changed to the second engagement groove 27. When the operation for insertion is started and the circumferential position of the operation pin 41 coincides with the second inclined surface 31, the energization is stopped.

  The first embodiment is characterized by the slider 20. The slider 20 protrudes in a radially outward direction from the radially outer surface 21 in the opposite direction to the first inclined surface 26, and the operation pin 41 pushed back radially outward by the first inclined surface 26 can be pushed back further radially outward. A projection 32 protrudes radially outward from the radially outer surface 21 in a direction opposite to the second inclined surface 31, and the operation pin 41 pushed back radially outward by the second inclined surface 31 can be further pushed back radially outward. And a protrusion 34. The first protrusion 32 has a third slope 33 that is continuous with the first slope 26 without a step. The 1st slope 26 and the 3rd slope 33 are the same planes. The second protrusion 34 has a fourth slope 35 that is continuous with the second slope 31 without a step. The second inclined surface 31 and the fourth inclined surface 35 are the same plane.

Next, the operation of the valve system 90 will be described with reference to FIGS. 1 and 6 to 10.
As shown in FIG. 1, when the cam shaft 92 rotates when the slider 20 is positioned at the first operating position, the rotational motion of the low-rotation cam 11 is transmitted to the intake valve 91 via the roller rocker 94, and the intake valve 91 Is converted into a reciprocating linear motion.

  In the state of FIG. 1, for example, when the engine speed reaches a high rotation range, when the circumferential position of the operation pin 41 with respect to the slider 20 coincides with the first engagement groove 22, the drive unit 42 moves the operation pin 41 to the first engagement. The operation for inserting into the joint groove 22 is started. The operation pin 41 is inserted into the first engagement groove 22 until the circumferential position with respect to the slider 20 reaches the first inner wall 25.

  As shown in FIG. 6, when the slider 20 rotates together with the cam shaft 92 with the operation pin 41 inserted into the first engagement groove 22, the slider 20 has the first inner wall 25 of the first engagement groove 22 connected to the operation pin 41. Is engaged, and the position in the axial direction is regulated, and as shown by the arrow A1 in FIG. When the circumferential position of the operation pin 41 with respect to the slider 20 coincides with the first slope 26, the drive unit 42 stops energization. Thereafter, the operation pin 41 is pushed back radially outward by the first inclined surface 26. In the first embodiment, the operation pin 41 is pushed back radially outward by the third inclined surface 33 of the first protrusion 32 as shown in FIG. 8 from the state where the tip end surface coincides with the radially outer surface 21 as shown in FIG. It is. As shown in FIG. 8, the amount by which the operation pin 41 is pushed back in the radially outward direction by the first protrusion 32 corresponds to the protruding amount of the first protrusion 32 in the radially outward direction.

  As shown in FIG. 9, when the cam shaft 92 rotates when the slider 20 is positioned at the second operating position, the rotational motion of the high-rotation cam 15 is transmitted to the intake valve 91 via the roller rocker 94, and the intake valve 91 Is converted into a reciprocating linear motion. When the rotational motion of the high-rotation cam 15 is converted into the reciprocating linear motion of the intake valve 91, the valve lift is larger than when the rotational motion of the low-rotation cam 11 is converted into the reciprocating linear motion of the intake valve 91. Become.

  In the state of FIG. 9, for example, when the engine speed reaches a low rotation range, when the circumferential position of the operation pin 41 with respect to the slider 20 coincides with the second engagement groove 27, the drive unit 42 moves the operation pin 41 to the second engagement. The operation for inserting into the mating groove 27 is started. The operation pin 41 is inserted into the second engagement groove 27 until the circumferential position with respect to the slider 20 reaches the second inner wall 30.

  As shown in FIG. 10, when the slider 20 rotates together with the cam shaft 92 with the operation pin 41 inserted into the second engagement groove 27, the slider 20 has the second inner wall 30 of the second engagement groove 27 connected to the operation pin 41. Is engaged, and the position in the axial direction is regulated, and as shown by an arrow A2 in FIG. When the circumferential position of the operation pin 41 with respect to the slider 20 coincides with the second inclined surface 31, the drive unit 42 stops energization. Thereafter, the operation pin 41 is pushed back radially outward by the second inclined surface 31. In the first embodiment, the operation pin 41 is further pushed back in the radially outward direction by the fourth inclined surface 35 of the second protrusion 34 from the state in which the distal end surface coincides with the radially outer surface 21. The amount by which the operation pin 41 is pushed back by the second protrusion 34 in the radially outward direction corresponds to the protrusion amount of the second protrusion 34 in the radially outward direction as in the case of the first protrusion 32.

  As described above, in the first embodiment, the slider 20 forms the first protrusion 32 and the second protrusion 34. The first protrusion 32 protrudes radially outward from the radially outer surface 21 of the slider 20 at a position opposite to the rotational direction with respect to the first slope 26 of the first engagement groove 22, and radially outwards by the first slope 26. The operation pin 41 that has been pushed back can be pushed back further in the radially outward direction. The second protrusion 34 protrudes radially outward from the radially outer surface 21 of the slider 20 at a position opposite to the rotational direction with respect to the second slope 31 of the second engagement groove 27, and radially outwards by the first slope 26. The operation pin 41 that has been pushed back can be pushed back further in the radially outward direction.

Therefore, since the operation pin 41 is pushed back radially outward from the radially outer surface 21 of the slider 20 by the projections 32 and 34, the first engaging groove 22 and The second engaging groove 27 is not contacted. Therefore, according to the first embodiment, the breakage of the operation pin 41 and the malfunction of the slider 20 can be suppressed.
Further, the backlash of the operation pin 41 can be allowed by the protruding amount of the first protrusion 32 and the second protrusion 34 in the radially outward direction. Therefore, since the operation pin 41 and the member such as the sleeve 43 to which the operation pin 41 is attached do not require high dimensional accuracy, the manufacturing cost can be reduced.
Further, the operation pin 41 starts operation from a position away from the outer diameter surface 21 of the slider 20 and is inserted into the engagement grooves 22 and 27 after being accelerated to some extent. Therefore, the operation control of the operation pin 41 is facilitated, and the operation pin 41 can be reliably inserted into the engagement grooves 22 and 27.

In the first embodiment, the third inclined surface 33 of the first protrusion 32 is connected to the first inclined surface 26 of the first engaging groove 22 without a step and is the same plane as the first inclined surface 26. Therefore, the operation pin 41 can smoothly transfer from the first slope 26 to the third slope 33.
In the first embodiment, the fourth inclined surface 35 of the second protrusion 34 is connected to the second inclined surface 31 of the second engagement groove 27 without a step and is the same plane as the second inclined surface 31. Therefore, the operation pin 41 can smoothly transfer from the second slope 31 to the fourth slope 35.

  In the first embodiment, the first engagement groove 22 and the second engagement groove 27 are formed so that their circumferential positions do not overlap each other, and the end portion in the opposite direction of the first engagement groove 22 is the second. The end of the engaging groove 27 in the rotational direction coincides with the axial position, and the end of the second engaging groove 27 in the opposite direction coincides with the rotational end of the first engaging groove 22 in the axial direction. ing. Therefore, the slider 20 can be moved to two operating positions with one operation pin 41.

(Second Embodiment)
A valve lift adjusting device according to a second embodiment of the present invention will be described with reference to FIGS. The valve lift adjusting device 50 includes a low-load cam 51 between the low-rotation cam 11 and the slider 52. The low load cam 51 is a disc cam that is spline-fitted to the cam shaft 92 at a position adjacent to one side in the axial direction with respect to the slider 52, and is integrated with the low rotation cam 11, the high rotation cam 15, and the slider 52. Is formed. The low load cam 51 corresponds to a “first cam” described in the claims. The low rotation cam 11 corresponds to the “first cam” described in the claims in relation to the high rotation cam 15, and is described in the claims in relation to the low load cam 51. It corresponds to a “second cam”.

The slider 52 includes a first operation position where the low rotation cam 11 contacts the roller rocker 94, a second operation position where the high rotation cam 15 contacts the roller rocker 94, and the low load cam 51 as the roller rocker. Each cam can be moved integrally with the third operating position to be brought into contact with 94.
The slider 52 has a first engagement groove 54 and a second engagement groove 59 extending in the rotation direction. The first engagement groove 54 is provided so that its axial position coincides with the second engagement groove 59 and its circumferential position does not overlap. The groove widths of the first engagement groove 54 and the second engagement groove 59 are set to be slightly larger than a value obtained by adding the outer diameter of the distal end portion of the operation pin 71 described later and the sliding amount of the slider 52. The sliding amount is a moving distance when the slider 52 moves from the first operating position to the second operating position. The moving distance when the slider 52 moves from the first operating position to the third operating position is the same as the moving distance when the slider 52 moves from the first operating position to the second operating position.

The other first inner wall 55 in the axial direction among the inner walls of the first engagement groove 54 forms a first convex portion 56 that protrudes toward one side in the axial direction toward the opposite direction. In addition, the bottom surface of the first engagement groove 54 has a first inclined surface 57 in which the depth from the outer surface 53 of the slider 52 becomes shallower in the opposite direction at the end portion in the opposite direction, and in the rotation direction at the end portion in the rotation direction. It has the 1st descent | fall surface 58 where the depth from the diameter outer surface 53 of the slider 52 becomes shallow, so that it goes.
The other second inner wall 60 in the axial direction among the inner walls of the second engagement groove 59 forms a second convex portion 61 that protrudes in one of the axial directions toward the opposite direction at the end portion in the opposite direction. Further, the bottom surface of the second engagement groove 59 has a second inclined surface 62 in which the depth from the outer surface 53 of the slider 52 becomes shallower in the opposite direction at the end portion in the opposite direction, and in the rotation direction at the end portion in the rotation direction. It has the 2nd downward surface 63 from which the depth from the diameter outer surface 53 of the slider 52 becomes shallow, so that it goes.

  The actuator 70 is an electromagnetic actuator, and includes two operation pins 71 and 72 and a drive unit 73. The operation pins 71 and 72 correspond to “operation members” described in the claims, and can be moved toward and away from the slider 52 from the radially outer direction. When the operation pin 71 is inserted into the first engagement groove 54 when the slider 52 is rotating at the first operation position, the operation pin 71 engages with the first protrusion 56 to move the slider 52 to the second operation position. When the slider 52 is rotating at the second operating position, if it is inserted into the second engaging groove 59, it engages with the second convex portion 61 and moves the slider 52 to the first operating position. When the operation pin 72 is inserted into the second engagement groove 59 when the slider 52 is rotating at the first operation position, the operation pin 72 engages with the second protrusion 61 to move the slider 52 to the third operation position. When the slider 52 is rotating at the third operating position, if it is inserted into the first engaging groove 54, it engages with the first convex portion 56 and moves the slider 52 to the first operating position.

  The drive unit 73 is fixed to the cylinder head 93 and supports the operation pins 71 and 72, the fixed cores 75 and 76 fixed in the sleeve 74, and fixed to the end of the operation pin 71 in the sleeve 74. A movable core 77 formed of a coil wound around the fixed core 75 and generating a magnetic field by energization, a movable core 78 fixed to the end of the operation pin 72 in the sleeve 74, and a fixed And a coil 80 that is formed of a winding wound around a core 76 and generates a magnetic field when energized. The movable core 77 includes a permanent magnet that repels the fixed core 75 magnetized by the magnetic field of the coil 79. The movable core 78 includes a permanent magnet that repels the fixed core 76 magnetized by the magnetic field of the coil 80. The drive unit 73 energizes the coil 79 and moves the movable core 77 away from the fixed core 75 to drive the operation pin 71 toward the slider 52, and energizes the coil 80 to separate the movable core 78 from the fixed core 76. The operation pin 72 is driven to the slider 52 side.

  The second embodiment is characterized by a slider 52. The slider 52 protrudes radially outward from the radially outer surface 53 in the opposite direction to the first slope 57, and can further push back the operation pins 71 and 72 pushed back radially outward by the first slope 57. The operation pins 71 and 72 that protrude outward in the radial direction from the outer surface 53 in the opposite direction to the first protrusion 64 and the second inclined surface 62 and are pushed back outward in the radial direction by the second inclined surface 62 are further pushed back in the radially outward direction. Possible second protrusions 65 are formed. The first protrusion 64 has a third slope 66 that continues to the first slope 57 without a step. The first slope 57 and the third slope 66 are the same plane. The second protrusion 65 has a fourth slope 67 connected to the second slope 62 without a step. The second slope 62 and the fourth slope 67 are the same plane.

  As described above, according to the second embodiment, the operation pins 71 and 72 are pushed back by the protrusions 64 and 65 in the radially outward direction from the radially outer surface 53 of the slider 52, and thus the same as in the first embodiment. There is an effect.

(Other embodiments)
In another embodiment of the present invention, the third inclined surface of the first protrusion and the fourth inclined surface of the second protrusion are not limited to planes, and may be curved surfaces.
In another embodiment of the present invention, the valve lift adjusting device may be applied to a valve system that opens and closes an exhaust valve.
In another embodiment of the present invention, the valve lift adjusting device is not limited to a valve system including a roller rocker, and may be applied to other types of valve systems.

In other embodiments of the present invention, each cam and slider may be coupled to the camshaft by methods other than spline fitting.
In other embodiments of the present invention, any difference in cam profiles between the cams may be provided.
The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 10 ... Valve lift adjustment apparatus 11 ... Low rotation cam (1st cam, 2nd cam)
15 ・ ・ ・ Cam for high rotation (second cam)
20, 52 ... slider 21, 53 ... outer diameter surface 22, 54 ... first engagement groove 25 ... first inner wall (inner wall of the first engagement groove)
26, 57 ... 1st slope 27, 59 ... 2nd engagement groove 30 ... 2nd inner wall (inner wall of 2nd engagement groove)
31, 62 ... second slope 32, 64 ... first protrusion 34, 65 ... second protrusion 41, 71, 72 ... operation pins (operation members)
42, 73 ... drive unit 51 ... low load cam (first cam)

Claims (4)

A valve lift adjusting device (10, 50) capable of changing a valve lift of an engine valve (91),
A first cam (11, 51) fitted to the cam shaft (92) so as to be capable of transmitting rotation and relatively moving in the axial direction;
A second cam (11, 15) which is located on one side in the axial direction with respect to the first cam and is fitted so as to be able to transmit rotation to the cam shaft and be relatively movable in the axial direction
The engine valve includes a first engagement groove (22, 54) and a second engagement groove (27, 59) coupled to the camshaft so as to be capable of transmitting rotation and relatively moving in the axial direction, and extending in the rotational direction. A cylindrical slider that moves integrally with the first cam and the second cam between a first operating position in which the engine valve is interlocked with the first cam and a second operating position in which the engine valve is interlocked with the second cam (20, 52),
The slider can be approached and separated from the outside in the radial direction, and is engaged with the inner walls (25, 55) of the first engagement groove when inserted into the first engagement groove when the slider is rotating. Then, when the slider is moved to the second operating position and is inserted into the second engaging groove when the slider is rotating, it engages with the inner walls (30, 60) of the second engaging groove. Operating members (41, 71, 72) for moving the slider to the first operating position;
A drive unit (42, 73) capable of driving the operation member toward the slider;
With
The bottom surface of the first engagement groove has a first slope (26, 57) whose depth from the outer surface (21, 53) of the slider is shallower toward the direction opposite to the rotation direction,
The bottom surface of the second engagement groove has a second slope (31, 62) whose depth from the outer surface is shallower toward the direction opposite to the rotation direction,
The slider protrudes radially outward from the radially outer surface at a position opposite to the rotational direction with respect to the first slope, and further pushes the operation member pushed back radially outward by the first slope in the radially outward direction. The first protrusion (32, 64) that can be pushed back and the second inclined surface protruded radially outward from the radially outer surface at a position opposite to the rotational direction, and pushed back radially outward by the second inclined surface. A valve lift adjusting device characterized in that a second protrusion (34, 65) capable of further pushing back the operating member in the radially outward direction is formed. The first protrusion has a third slope (33, 58) connected to the first slope without a step,
2. The valve lift adjusting device (10, 50) according to claim 1, wherein the second protrusion has a fourth inclined surface (35, 63) connected to the second inclined surface without a step. The third slope is the same plane as the first slope,
The valve lift adjusting device (10, 50) according to claim 2, wherein the fourth slope is the same plane as the second slope.   The valve lift adjusting device according to any one of claims 1 to 3, wherein the first engagement groove and the second engagement groove are provided so that circumferential positions thereof do not overlap each other. (10, 50).

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