JP5991289B2 - Variable valve operating apparatus for internal combustion engine and variable valve operating system for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine and a variable valve operating system for the internal combustion engine.

  In the variable valve operating apparatus of Patent Document 1, a movable cam connected to a camshaft so as to advance and retract is provided. When the movable cam is locked at a position protruding from the camshaft and the camshaft rotates, the movable cam drives a valve that is a cam follower.

JP 2001-329819 A

  When the lock is released, the movable cam moves by receiving force from the cam follower as the cam shaft rotates. However, for example, when the force applied to the movable cam from the cam follower is small, there is a possibility that the movable cam does not retreat smoothly and the cam follower is driven unintentionally.

  Accordingly, it is an object of the present invention to provide a variable valve operating apparatus for an internal combustion engine with improved operational stability and a variable valve operating system for an internal combustion engine including the same.

  The object is to provide a cam base portion that rotates together with a cam shaft, a cam lobe portion that is connected to the cam base portion so as to be swingable between a high position protruding from the outer periphery of the cam base portion and a low position lower than the high position, A biasing member that biases the cam lobe portion to the high position, a cam follower that presses the cam lobe portion toward the low position side, and a lock mechanism that locks the cam lobe portion at the high position. The rotation direction is a direction opposite to the direction in which the cam lobe portion is urged by the urging member, and the cam base portion includes a base circle portion and a protrusion provided on the base circle portion, When viewed from the axial direction of the camshaft, the projecting portion is provided at a portion that transitions from the outer surface of the base circle portion to the outer surface of the cam lobe portion at the high position in the direction opposite to the rotational direction. It is, can be achieved by the variable valve device for an internal combustion engine.

  The protrusion may be configured to open the engine valve when the piston is positioned at a top dead center or a bottom dead center with the cam lobe portion unlocked at the high position.

  When the piston is located at the top dead center or the bottom dead center in a state where the lock of the cam lobe portion at the high position is released, the projecting portion opens the engine valve. A variable valve system for an internal combustion engine comprising a phase change device that changes a phase of the cam base portion.

  It is possible to provide a variable valve system for an internal combustion engine with improved operational stability and a variable valve system for an internal combustion engine including the same.

FIG. 1 is an external view of the variable valve operating apparatus of the present embodiment. FIG. 2 is an external view of the variable valve operating apparatus of the present embodiment. 3A and 3B are sectional views of the cam unit as seen from the axial direction. 4A and 4B are cross-sectional views showing the internal structure of the cam unit. 5A to 5C are explanatory diagrams of the lock of the cam lobe portion. 6A and 6B are explanatory diagrams of the lock of the cam lobe portion. 7A and 7B are enlarged views of the protrusions corresponding to FIGS. 3A and 3B, respectively. FIG. 8 is a diagram showing a comparative example. FIG. 9 is an explanatory diagram of an unintended valve lift. FIG. 10 is an explanatory diagram in the case where the valve is opened by the protrusion in the lift stop state.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  1 and 2 are external views of the variable valve operating apparatus 1 of the present embodiment. The variable valve operating apparatus 1 is employed in an internal combustion engine mounted on a vehicle or the like. The variable valve operating apparatus 1 includes a camshaft S and a cam unit CU provided on the camshaft S. The camshaft S includes a portion SA connected to one end of the cam unit CU and a portion SB connected to the other end of the cam unit CU. The camshaft S is rotated by power from the internal combustion engine. When the cam unit CU rotates together with the camshaft S, the valve V is lifted via the rocker arm R. The valve V is an intake valve or an exhaust valve of an internal combustion engine, and is an example of an engine valve.

  The cam unit CU includes a cam base portion 10 having a diameter larger than that of the cam shaft S and connected to the portions SA and SB of the cam shaft S, and two cam lobe portions 20 connected to the cam base portion 10. The cam base portion 10 has a substantially cylindrical shape, and has a substantially circular base circle portion 11 when viewed from the axial direction of the camshaft S (hereinafter referred to as the axial direction). The base circle portion 11 corresponds to the outer peripheral surface of the cam base portion 10. The two cam lobes 20 are arranged at a predetermined interval in the axial direction. The two cam lobes 20 push the two rocker arms R and lift the two valves V, respectively. The axial thickness of the cam base portion 10 is thicker than the axial thickness of the cam lobe portion 20.

  As shown in FIG. 2, the cam base portion 10 has a recess 10 </ b> H formed between two cam lobe portions 20. The recess 10 </ b> H is formed between portions where the two rocker arms R contact the cam base portion 10. The recess 10H does not contact the rocker arm R. The two support shafts 33 penetrate the two cam lobe parts 20 together with the cam base part 10 in the axial direction. The cam lobe portion 20 swings with respect to the cam base portion 10 with the support shaft 33 as a fulcrum. The cam lobe portion 20 can swing between a high position that protrudes from the base circle portion 11 of the cam base portion 10 to the maximum and a low position that does not protrude from the base circle portion 11. The end of the support shaft 33 is exposed in the recess 10H. Each of the two cam lobes 20 is provided with a stopper pin 34P.

  In the recess 10 </ b> H of the cam base 10, two springs 34 s are wound around the end of the support shaft 33. One end of the spring 34s pushes the inner surface of the recess 10H, and the other end of the spring 34s pushes the stopper pin 34P. That is, the spring 34s biases the stopper pin 34P so as to separate from the recess 10H. As a result, the cam lobe portion 20 is biased so as to protrude from the cam base portion 10. The spring 34s is an example of an urging member.

  1 and 2, the left cam lobe portion 20 is at a high position, and the right cam lobe portion 20 is at a low position. In this embodiment, when the cam lobe 20 is locked at the high position, the cam lobe 20 drives the rocker arm R to lift the valve V. When the cam lobe 20 is locked at the low position, the cam lobe 20 contacts or does not contact the rocker arm R and the valve V does not lift. In FIGS. 1 and 2, only one cam lobe portion 20 is at a high position for easy understanding, but actually, the two cam lobe portions 20 are both located at the same position as will be described later.

  3A and 3B are sectional views of the cam unit CU as seen from the axial direction. 3A shows the cam lobe 20 in the high position, and FIG. 3B shows the cam lobe 20 in the low position. The cam lobe portion 20 has a substantially U shape or a substantially L shape that avoids the path T of the cam base portion 10. A support shaft 33 passes through the base end side of the cam lobe portion 20. 3A and 3B, the camshaft S rotates counterclockwise. Along with this, the cam base portion 10 and the cam lobe portion 20 also rotate counterclockwise. A long hole 14 through which the stopper pin 34P passes is formed in the cam base portion 10. The long hole 14 regulates the movement range of the stopper pin 34 </ b> P that moves along with the rocking of the cam lobe 20, thereby restricting the rocking range of the cam lobe 20.

  As shown in FIGS. 3A and 3B, the base circle portion 11 of the cam base portion 10 is partially provided with a protrusion 11a. The protrusion 11a is a portion that transitions from the outer surface of the base circular portion 11 to the outer surface of the cam lobe portion 20 in the direction opposite to the rotation direction of the cam base portion 10 when viewed from the axial direction when the cam lobe portion 20 is at a high position. Is provided. The height of the protrusion 11a from the base circle part 11 is lower than the maximum height of the cam lobe part 20 located at a high position from the base circle part 11. The protrusion 11a is formed on the base circle 11 so as to extend in the axial direction. The protrusion 11a is formed over a range of about 10 to 30 ° around the camshaft S, for example. Details of the protrusion 11a will be described later.

  The spring 34s urges the cam lobe 20 around the support shaft 33 in the clockwise direction. Therefore, the urging direction of the cam lobe portion 20 by the spring 34s is opposite to the rotation direction of the camshaft S.

  4A and 4B are cross-sectional views showing the internal structure of the cam unit CU. 4A and 4B, the two cam lobes 20 are both in a lifted state. 4A and 4B correspond to the AA cross-sectional view of FIG. 3A. As shown in FIGS. 4A and 4B, the cam unit CU is formed symmetrically in the axial direction at the center of the cam unit CU in the axial direction. Therefore, in the following description, one of the two cam lobes 20 will be described. The cam base portion 10 is formed with a slit 12 that can accommodate the cam lobe portion 20. A path T extending on the axis of the camshaft S and paths T5 and T6 extending radially outward from the path T are formed in the cam base portion 10. The paths T5 and T6 respectively extend radially outward from the path T, and then extend in the axial direction to the two cam lobe portions. The route T6 is an example of a first route. The route T5 is an example of a second route.

  The oil control valve OCV is an electromagnetically driven flow control valve and is controlled by the ECU 5. The ECU 5 is an example of a control unit. Oil stored in the oil pan is supplied into the path T by the oil pump P. The oil pump P is a mechanical type interlocked with the crankshaft of the internal combustion engine. The oil control valve OCV can linearly adjust the hydraulic pressure supplied in the path T by the oil pump P based on the current value applied to the oil control valve OCV. The oil control valve OCV is an example of a hydraulic control valve. The hydraulic control valve may be capable of adjusting the hydraulic pressure supplied into the path T in stages. The ECU 5 includes a CPU, a ROM, a RAM, and the like, and controls the operation of the entire internal combustion engine. The ROM stores a program for executing control described later.

  The cam base portion 10 holds pins 15P, 16P, and 17P that act on the two cam lobe portions 20, respectively. Each of the two cam lobes 20 holds a pin 26P. The pin 26P is an example of a lock member. FIG. 4B is a diagram in which the pins 15P and the like are omitted. The cam lobe portion 20 has a free end portion away from the base end portion through which the support shaft 33 passes, and a hole 26 holding a pin 26P is formed on the free end portion side of the cam lobe portion 20. The hole 26 penetrates the cam lobe 20 in the axial direction. The hole 26 is an example of a holding hole.

  Holes 15 and 16 communicating with the slit 12 are formed in the cam base portion 10. The holes 15 and 16 are formed on the same side with respect to the slit 12. The holes 15 and 16 extend in the axial direction and have a bottom surface. Pins 15P and 16P are accommodated in the holes 15 and 16, respectively. A spring 15S connected to the pin 15P is arranged between the bottom surface of the hole 15 and the pin 15P. A spring 16S connected to the pin 16P is disposed between the bottom surface of the hole 16 and the pin 16P. The spring 16S biases the pin 16P toward the cam lobe portion 20. The spring 15S is set to such a length that the pin 15P does not detach from the hole 15. The spring 15S is an example of a second spring. The spring 16S is an example of a first spring.

  A hole 17 is formed in the cam base portion 10 so as to face the hole 16 through the slit 12. In the hole 17, a pin 17P is accommodated. The hole 17 communicates with the path T6. The hole 17 is located coaxially with the hole 16. The hole 17 extends in the axial direction.

  When the cam lobe 20 is at a high position, the holes 16, 17, and 26 are aligned in the axial direction, and the pins 16P, 17P, and 26P are aligned in the axial direction. In other words, the swing range of the cam lobe portion 20 is defined by the long hole 14 engaged with the stopper pin 34P so that the cam lobe portion 20 is positioned at such a position at one end of the swing range. In the lift state, the pin 16P is inserted into the holes 16 and 26 in common by the biasing force of the spring 16S, and the pin 26P is inserted into the holes 26 and 17 in common. Thereby, the cam lobe part 20 is locked to the cam base part 10 in a lift state. The hole 17 is an example of a first lock hole.

  Further, as shown in FIG. 4A, a known phase change device 8 capable of changing the phase of relative rotation of the camshaft S with respect to the crankshaft is provided. By changing the phase of the camshaft S, the opening / closing timing of the valve opened and closed by the cam unit CU can be changed. Also in the phase changing device 8, the phase of the camshaft S is changed by the hydraulic pressure supplied by the oil control valve OCV 'and the oil pump P'.

  Next, the locking of the cam lobe 20 will be described in detail. 5A to 6B are explanatory views of the lock of the cam lobe portion 20. When oil is supplied into the paths T5 and T6 via the path T by the oil control valve OCV and the oil pump P, as shown in FIG. 5A, the pin 17P resists the urging force of the spring 16S and the cam lobe 20 side Pressed. Thereby, the pin 16P is detached from the hole 26, and the pin 26P is detached from the hole 17. That is, the pins 16P, 17P, and 26P are accommodated in the holes 16, 17, and 26, respectively. Thereby, the lock | rock of the cam lobe part 20 is cancelled | released in a high position.

  When the camshaft S rotates with the cam lobe 20 unlocked, the cam lobe 20 receives the reaction force from the rocker arm R in order. Accordingly, as shown in FIG. 5B, the cam lobe 20 moves to a low position against the urging force of the spring 34s. In other words, the urging force of the spring 34s is set to such an extent that the cam lobe 20 can be moved to a low position only by the reaction force from the rocker arm R in a state where the lock of the cam lobe 20 is released. In this way, the rocker arm R urges the cam lobe portion 20 that has been unlocked to the low position side. When the cam lobe portion 20 is in the low position, the holes 15 and 26 are aligned on the same axis. In other words, the swing range of the cam lobe portion 20 is defined by the long hole 14 engaged with the stopper pin 34P so that the cam lobe portion 20 is positioned at such a position at the other end of the swing range. The rocker arm R is an example of a cam follower for driving a bubble. The cam follower may be a valve lifter that is directly driven by the cam.

  As shown in FIG. 5C, the pin 26P is inserted into the holes 15 and 26 in common against the urging force of the spring 15S by the pressure of the oil from the path T5. Thereby, the cam lobe part 20 is locked in a lift stop state. As described above, the cam lobe portion 20 is locked at the low position while the oil is supplied into the path T at a predetermined pressure or higher. The hole 15 is an example of a second lock hole.

  Next, when the oil supply to the path T is stopped by the oil control valve OCV, the pin 26P is detached from the hole 15 and accommodated in the hole 26 by the urging force of the spring 15S as shown in FIG. 6A. As a result, the cam lobe 20 is unlocked at the low position.

  Next, according to the urging force of the spring 34s, the cam lobe portion 20 moves from the low position to the high position as shown in FIG. 6B. Actually, while the cam lobe 20 is not in contact with the rocker arm R, the cam lobe 20 moves to the high position according to the biasing force of the spring 34s. In the state where the cam lobe 20 is at the high position, the pins 16P, 26P, and 17P are arranged in the axial direction as described above.

  In this state, as shown in FIG. 4A, the pin 16P is inserted into the holes 16 and 26 in common according to the urging force of the spring 16S, and similarly the pin 26P is inserted into the holes 26 and 17 in common. Thereby, the cam lobe part 20 is locked in a high position. As described above, the cam lobe 20 is locked at the high position and the low position. The hole 26, the pin 26P, the springs 15S and 16S, the holes 15 and 17 and the like are examples of a lock mechanism. Thus, since the cam lobe part 20 is locked even at a low position, the cam lobe part 20 can be held in a stable state, and reliability and durability are ensured.

  As shown in FIGS. 1, 2, 3 </ b> A, 3 </ b> B, 4 </ b> A, and 4 </ b> B, the cam base portion 10 is connected to the cam shaft S, and the cam shaft S does not penetrate the cam base portion 10. For this reason, the axial cross-sectional area of the cam base part 10 can be ensured, and the strength of the cam base part 10 can be ensured. Since the camshaft S does not penetrate the cam base portion 10, it is not necessary to reduce the diameter of the camshaft S. For this reason, the strength of the camshaft S is also ensured. The holes 15, 16, and 17 formed in the cam base portion 10, the holes 26 formed in the cam lobe portion 20, and the like all extend in the axial direction. For this reason, for example, compared with the case where a hole extending in a direction crossing the axial direction is provided and a pin sliding in the hole is arranged, the cross-sectional area in the axial direction of the cam base portion 10 can be secured. . Thereby, the strength of the cam unit CU is ensured.

  As shown in FIGS. 3A and 3B, the free end of the cam lobe portion 20 is separated from the base end side of the cam lobe portion 20 in the reverse direction from the rotation direction of the camshaft S. Here, the base end side of the cam lobe portion 20 serves as a fulcrum for swinging by the support shaft 33. For this reason, it becomes easy for the cam lobe portion 20 to swing in the direction opposite to the rotation direction of the camshaft S due to the reaction force of the rocker arm R. This facilitates the movement of the cam lobe portion 20 from the low position to the high position in the unlocked state. Moreover, the load by the reaction force from the rocker arm R which the cam lobe part 20 receives when moving to a low position is reduced, and the durability of the cam lobe part 20 is ensured.

  The cam base portion 10 supports two cam lobe portions 20. For this reason, since the cam base part 10 has secured the length of the axial direction, the intensity | strength is ensured. In addition, since the cam base portion 10 is shared by the two cam lobe portions 20, the number of parts is reduced.

  2 and 4A, the springs 15S, 16S, and 34s are arranged in the axial direction with respect to the cam lobe portion 20. For example, as compared with the case where such a spring 34 s is disposed at a position overlapping the cam lobe portion 20 in the radial direction, the cross-sectional area in the axial direction of the cam lobe portion 20 can be ensured. Thereby, the strength of the cam lobe portion 20 can be ensured.

  Further, as described above, since the recess 10H in which the spring 34s is disposed is provided in a portion that does not contact the rocker arm R, this portion is effectively used. Since the spring 34s is disposed at a position retracted from the portion of the cam base portion 10 that contacts the rocker arm R, the cross-sectional area in the axial direction of the portion of the cam base portion 10 that contacts the rocker arm R is also secured. Thereby, the strength of the cam base portion 10 is also ensured.

  As shown in FIG. 3A, the outlet of the path T5 is formed to open to the slit 12, and this outlet is closed by the cam lobe 20 when the cam lobe 20 is in the high position. The cam lobe portion 20 extends on the tip side so as to close the outlet. For this reason, when switching the position of the cam lobe part 20 from a high position to a low position, it can prevent that oil flows out from the exit of the path | route T5. Thereby, the fall of the oil_pressure | hydraulic in path | route T, T5, T6 can be suppressed, and the fall of the responsiveness of the unlocking | release of the cam lobe part 20 in a high position is suppressed.

  Next, the protrusion 11a will be described. 7A and 7B are enlarged views of the protrusion 11a corresponding to FIGS. 3A and 3B, respectively. As shown in FIG. 7A, the protrusion 11a protrudes in the radial direction from the vicinity of the boundary between the outer surface of the base circle 11 and the outer surface of the cam lobe 20 at a high position when viewed in the axial direction. Thus, the protrusion 11a protrudes outward from the cam lobe 20 at the high position. For this reason, when the cam lobe part 20 is locked at a high position, the rocker arm R in the order of the base circle part 11, the projecting part 11 a, the cam lobe part 20, and the base circle part 11 as the cam base part 10 rotates counterclockwise. Touch the roller. When the lock of the cam lobe 20 at the high position is released, the cam lobe 20 is retracted from the high position to the low position under the force of the rocker arm R as the cam base 10 rotates. The protrusion 11a is provided to assist the retreating movement of the cam lobe 20 as described above.

  FIG. 8 is a diagram showing a comparative example. In the comparative example, the base circle part 11 is not provided with the protrusion 11a. The force that the cam lobe portion 20 applies to the rocker arm R and the force that the cam lobe portion 20 receives from the rocker arm R when the cam lobe portion 20 is unlocked at the high position will be described. The action point PP is a point on the outer surface of the cam lobe portion 20 that contacts the rocker arm R, and the surface that contacts the rocker arm R as the cam shaft S rotates is changed from the outer surface of the base circle portion 11 to the outer surface of the cam lobe portion 20. This is a point on the outer surface of the cam lobe portion 20 that comes into contact with the rocker arm R immediately after the transition to. The tangent line L1 is a tangent line at the action point PP.

  The perpendicular line L2 passes through the center of the support shaft 33 and is perpendicular to the tangent line L1. The center of the support shaft 33 is a fulcrum for swinging the cam lobe portion 20. The distance L indicates the distance from the intersection of the tangent line L1 and the perpendicular line L2 to the action point PP. The force F indicates the force with which the cam lobe 20 pushes the rocker arm R at the point of action PP. If the moment N acting on the cam lobe 20 by the spring 34s is assumed, it can be expressed as moment N = distance L × force F. The valve V is provided with a valve spring (not shown) that urges the valve V to close. The valve spring load RP indicates the load that the valve spring applies to the cam unit CU. Due to the relationship between the force F and the valve spring load RP, the cam lobe 20 is retracted.

  Here, in a state where the cam lobe portion 20 is biased to the high position, the moment N acting on the cam lobe portion 20 by the spring 34s is constant. For this reason, the force F increases as the distance L decreases. Therefore, if the force F increases and exceeds the valve spring load RP, the cam lobe 20 may not smoothly retreat to the low position. As a result, the rocker arm R may be driven unintentionally and the valve may be driven.

  FIG. 9 is an explanatory diagram of an unintended valve lift. FIG. 9 shows the normal lift amount of the valve V in the lift state and the lift stop state. As described above, although the cam lobe 20 is unlocked at the high position, an unintended valve lift may occur at the early stage of the valve opening timing.

  In this embodiment, the protrusion 11a is provided as described above. Thereby, in the process in which the surface in contact with the rocker arm R moves from the base circle portion 11 to the cam lobe portion 20, the protrusion 11a contacts the rocker arm R, and the rocker arm R is pushed by the protrusion 11a to slightly increase the valve V. Lifts. As the valve V lifts, the valve spring is compressed and the valve spring load RP increases. When the cam lobe portion 20 comes into contact with the rocker arm R after the valve spring load RP increases, the cam lobe portion 20 receives the increased valve spring load RP. Thereby, the retreating movement of the cam lobe part 20 is promoted.

  Moreover, the distance L becomes large by providing the protrusion 11a. The greater the distance L, the smaller the force F. Thereby, the retreating movement of the cam lobe part 20 is promoted.

  As described above, the retreat movement of the cam lobe portion 20 is promoted, so that an unexpected lift of the valve V in a state where the lock at the high position is released is suppressed. Thereby, the stability of the operation of the variable valve mechanism 1 is ensured.

  As shown in FIGS. 4 to 6, the axial length of the protrusion 11 a is formed over the entire cam base 10, but is not limited thereto. That is, the length of the protrusion 11a in the axial direction only needs to be long enough to contact the rocker arm R.

  Next, a case where the valve is opened by the protrusion 11a in the lift stop state will be described. FIG. 10 is an explanatory view when the valve is opened by the protrusion 11a in the lift stop state. The variable valve operating apparatus 1 of the present embodiment is provided on both the intake camshaft and the exhaust camshaft. The phase change device 8 described above is also provided on both the intake camshaft and the exhaust camshaft. The two phase change devices 8 respectively change the rotation phases of the intake camshaft and the exhaust camshaft with respect to the crankshaft.

  In the valve stop state, the ECU 5 changes the phase of the intake camshaft by the intake-side phase change device 8 so that the protrusion 11a of the intake-side variable valve apparatus 1 opens the intake valve at the top dead center. Similarly, in the valve stop state, the ECU 5 changes the phase of the exhaust camshaft by the exhaust-side phase change device 8 so that the projection 11a of the exhaust-side variable valve device 1 opens the exhaust valve at the bottom dead center. . As described above, by opening the intake valve at the top dead center and opening the exhaust valve at the bottom dead center, the amount of volume change in the cylinder can be reduced. Thereby, the increase in pump loss can be suppressed.

  The intake valve or the exhaust valve may be opened at either the top dead center or the bottom dead center. Therefore, the phase changing device 8 may be provided only on one side of the intake camshaft or the exhaust camshaft.

  In FIG. 10, the maximum lift amounts of the intake valve and the exhaust valve in the valve lift state are different. This is because the high positions of the cam lobes 20 are different in the variable valve gears 1 arranged on the intake side and the exhaust side, respectively. Thus, the variable valve gears 1 having different cam lobe portions 20 may be disposed on the intake side and the exhaust side. The same variable valve gear 1 may be arranged on the intake side and the exhaust side.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  In the present embodiment, the case where the cam lobe portion 20 is in a position where it does not protrude from the cam base portion 10 is described as a low position. However, the present invention is not limited to this. For example, the cam lobe portion 20 has a high position that protrudes from the base circle portion 11 of the cam base portion 10 and a low position that protrudes from the base circle portion 11 although the protrusion amount is smaller than the first high position. You may rock | fluctuate between.

  In the lift state, the oil pressure may be applied directly to the pin 26P without using the pin 17P. Further, the springs 15S and 16S may directly bias the pin 26P without using the pins 15P and 16P.

  The cam base portion 10 may be molded integrally with the cam shaft, or may be joined after being molded separately as in this embodiment.

  The locking mechanism may lock the cam lobe 20 only at the high position and not at the low position. That is, the cam base unit 10 may not include the path T5, 15, 15P, and 15S. In this case, the cam lobe 20 rotates together with the cam base 10 while reciprocating between the high position and the low position by the biasing force of the spring 34s and the force from the rocker arm R in the unlocked state.

  The lock mechanism is not limited to the one that locks the cam lobe 20 by the action of hydraulic pressure. For example, a lock member that locks the cam lobe 20 may be driven by an actuator.

1 Variable valve gear 5 ECU
S Camshaft R Rocker arm (Cam follower)
V valve N nut 10 cam base portion 11 base circle portion 11a protrusion 20 cam lobe portion 34s spring (biasing member)

Claims (3)

A cam base that rotates with the camshaft;
A cam lobe connected to the cam base so as to be swingable between a high position protruding from the outer periphery of the cam base and a low position lower than the high position;
A biasing member that biases the cam lobe portion to the high position;
A cam follower for pressing the cam lobe portion toward the low position;
A lock mechanism for locking the cam lobe portion at the high position,
The direction of rotation of the cam base portion is opposite to the direction in which the cam lobe portion is urged by the urging member,
The cam base portion includes a base circle portion, a protrusion provided on the base circle portion,
When viewed from the axial direction of the camshaft, the protrusion is provided on a portion that transitions from the outer surface of the base circle portion to the outer surface of the cam lobe portion at the high position in a direction opposite to the rotation direction. A variable valve operating device for an internal combustion engine.   The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the protrusion opens the engine valve when the piston is located at a top dead center or a bottom dead center with the cam lobe portion unlocked at the high position. . A variable valve operating apparatus for an internal combustion engine according to claim 1,
A phase change device that changes the phase of the cam base portion so that the protrusion opens the engine valve when the piston is positioned at the top dead center or the bottom dead center with the cam lobe portion unlocked at the high position. And a variable valve system for an internal combustion engine.

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