JP2017044160A - Variable valve mechanism of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the fluttering of an output arm in a rest state, even if a resting cam or a resting spring are not provided, and to fix a rest position thereof.SOLUTION: A variable valve mechanism 1 is equipped with an input arm 20; an output arm 30; and a switch device 50A which couples both arms 20 and 30 to switch to a drive state, and releases the coupling to switch to a rest state. A locking device 50B is provided, which holds the output arm 30 in a predetermined holding section M in a close valve section by locking the output arm 30 to a cam housing 5, in the rest state, and releases the locking in the drive state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable valve mechanism that drives a valve of an internal combustion engine and changes the drive state of the valve in accordance with the operating state of the internal combustion engine.

  A variable valve mechanism 90 of Conventional Example 1 (Patent Document 1) shown in FIG. 11 includes an input arm 92, an output arm 93, and a switching device 95. The input arm 92 is driven by the cam 91 and swings. The output arm 93 is swingably provided, and drives the valve 7 when swinging. The switching device 95 switches to a driving state in which the valve 7 is driven by connecting both the arms 92 and 93, and switches to a resting state in which the driving of the valve 7 is stopped by releasing the connection.

  12 and 13, the variable valve mechanism 90 ′ of the conventional example 2 (Patent Document 2: unpublished at the time of filing) includes an input arm 92, an output arm 93, and a switching device 95 as in the conventional example 1. In addition to being provided, the output arm 93 is divided into a first arm 93A and a second arm 93B. The first arm 93A is connected to the input arm 92 in the driving state, and the second arm 93B swings together with the first arm 93A to drive the valve 7. Then, the lift amount changing device 94 changes the lift angle of the valve 7 in the driving state by changing the relative angle in the swing direction of the second arm 93B with respect to the first arm 93A.

JP 2009-91969 A Japanese Patent Application No. 2015-92769

  In the case of the variable valve mechanism 90 of Conventional Example 1 shown in FIG. 11, with only the basic structure described above, the output arm 93 disconnected from the input arm 92 may be fluttered in the rest state. Therefore, the camshaft 91x is provided with a resting cam 91A having a circular cross-sectional shape that suppresses the fluttering by contacting the output arm 93.

  Further, in the case of the variable valve mechanism 90 ′ of the conventional example 2 shown in FIGS. 12 and 13, the output arm 93 may be fluttered just like the conventional example 1 with the above basic structure alone. There is also a problem shown in. That is, the rest position of the first arm 93A is changed by changing the relative angle with respect to the second arm 93B. Therefore, the rest position of the first arm 93A is not fixed, and depending on the rest position, switching to the driving state (connection of both arms 92 and 93) may be impossible or difficult. Therefore, as shown in FIG. 13, the camshaft 91x is provided with a pausing cam 91A, and a pausing spring 97 that biases the first arm 93A against the pausing cam 91A is provided, thereby pausing the first arm 93A. And the fluttering of the output arm 93 is suppressed.

  However, in the conventional examples 1 and 2, the structure of the variable valve mechanism is complicated by the suspension cam 91A and the suspension spring 97. Therefore, even if there is no pause cam (or stopper) or pause spring, the output arm does not flap in the pause state, and the pause position is also fixed, so that the pause cam and pause spring It is an object of the present invention to make the spring obsolete.

  In order to achieve the above object, a variable valve mechanism for an internal combustion engine of the present invention is configured as follows. That is, a cam provided on a camshaft that is rotatably supported by the cam housing and rotates according to the rotation of the internal combustion engine, an input arm that is driven by the cam and swings, a valve opening section that opens the valve, and a valve that closes the valve By connecting both arms so that the output arm swings together with the input arm and the output arm swingably provided in the valve section, the drive state is switched to drive the valve, and the connection is released. Thus, a switching device for switching to a dormant state in which the drive of the valve is suspended is provided. In this variable valve mechanism, the output arm is locked to the cam housing in the resting state, thereby holding the output arm in a predetermined holding section in the valve closing section, and releasing the locking in the driving state. A locking device is provided.

Although the specific aspect of this variable valve mechanism is not particularly limited, the following aspects i and ii are exemplified. However, the aspect of ii is preferable in that the engine performance is further improved and the effect of the present invention can be further exhibited.
[I] A mode in which the lift amount of the valve in the driving state is not changed only by switching between the driving state and the resting state.
[Ii] A mode in which the lift amount of the valve in the driving state is changed in addition to switching between the driving state and the resting state.

  Although the specific aspect of said ii is not specifically limited, The following aspect is illustrated. That is, the output arm is divided into a first arm connected to the input arm in a driving state and a second arm that swings together with the first arm to drive the valve. The variable valve mechanism includes a lift amount changing device that changes the lift amount of the valve in the driving state by changing a relative angle of the swinging direction of the second arm with respect to the first arm. The output arm is locked by the locking device by locking the first arm to the cam housing.

  According to the present invention, in the resting state, the output arm is held in the predetermined holding section by the locking device, so that the output arm does not flutter. Therefore, it is possible to eliminate the pause cam (or stopper) as shown in Conventional Example 1 that suppresses the flutter of the output arm.

  Furthermore, in the specific embodiment of ii, the following effects can also be obtained. That is, in the resting state, since the first arm is held by the locking device, the resting position of the first arm is fixed without being changed by changing the relative angle with the second arm. For this reason, not only can the pausing cam (or stopper) be abolished, but also the pausing spring as shown in the prior art 2 that fixes the pausing position by urging the first arm thereto can be eliminated.

In the variable valve mechanism of Embodiment 1, a is a rear sectional view showing a driving state, and b is a rear sectional view showing a resting state. In the same variable valve mechanism, it is a back sectional view which shows change from a drive state to a rest state in order of ac. In the same variable valve mechanism, it is a back sectional view which shows change from a rest state to a drive state in order of ac. In the drive state of the variable valve mechanism, a is a side sectional view showing the base circle (a sectional view taken along VIa-VIa shown in FIG. 1a), and b is a side sectional view showing the nose. In the rest state of the variable valve mechanism, a is a side sectional view showing the base circle (Va-Va sectional view shown in FIG. 1b), and b is a side sectional view showing the nose. It is a perspective view which shows the variable valve mechanism. It is a perspective view which shows the input arm, output arm, etc. of the variable valve mechanism. It is an exploded perspective view of the input arm and the output arm. In the variable valve mechanism of Embodiment 2, a is a rear sectional view showing a driving state, and b is a rear sectional view showing a resting state. It is a disassembled perspective view which shows the input arm, output arm, etc. of the variable valve mechanism of Example 3. It is a perspective view which shows the variable valve mechanism of the prior art example 1. FIG. It is a perspective view which shows the input arm, output arm, etc. of the variable valve mechanism of the prior art example 2. It is side surface sectional drawing which shows the variable valve mechanism.

  Although the switching device and the locking device may be provided separately, it is preferable that the switching device and the locking device are incorporated in one device in terms of compactness. Specifically, the following configuration is exemplified.

  That is, the switching device and the locking device are incorporated in the switching locking device. The switching locking device includes a switching pin that is displaceable between a connecting position for connecting the arms and a non-connecting position for releasing the connection, a locking position for locking the output arm to the cam housing, and the engagement thereof. A locking pin that is displaceably provided at a non-locking position for releasing the stop, an interposition pin interposed between the switching pin and the locking pin, and a displacement device are provided. The displacing device displaces the switching pin, the interposition pin, and the locking pin in one direction by ball hitting, thereby arranging the switching pin at the coupling position and arranging the locking pin at the non-locking position. By displacing in the other direction opposite to the direction, the switching pin is arranged at the non-connection position and the locking pin is arranged at the locking position. The portion including the switching pin of the switching locking device constitutes the switching device, and the portion including the locking pin of the switching locking device constitutes the locking device.

  The locking device may be configured to restrain the output arm completely unrotatable in the swinging direction in the resting state, but more smoothly switches from the resting state to the driving state (both arms are connected). In view of the above, the following embodiment is preferable.

  That is, the holding of the output arm by the locking device allows the output arm to swing within the holding section. In the resting state, the contact portion provided in the input arm is provided in the output arm immediately before the base circle in which the cam base circle acts in the nose in which the cam nose acts. The contact state, which is in contact with the base plate from the swinging direction side, continues until just after the base circle passes through the base circle, and in the contact state, the output arm and the input arm It is configured to swing within the holding section. Then, switching from the resting state to the driving state by the switching device is performed by connecting both arms in the contact state.

  Next, examples of the present invention will be described. However, the present invention is not limited to the embodiments, and the configuration and shape of each part can be arbitrarily changed without departing from the spirit of the invention.

  The variable valve mechanism 1 of Example 1 shown in FIGS. 1-8 is provided with respect to a pair of valves 7 and 7 to which the valve springs 8 and 8 were attached, as shown in FIG. The pair of valves 7 and 7 may be a pair of intake valves or a pair of exhaust valves. The variable valve mechanism 1 includes a cam 10, an input arm 20, an output arm 30, a lift amount changing device 40, and a switching locking device 50. In the following, in accordance with FIG. 1 and the like, one of the arms 20 and 30 in the width direction is referred to as “left” and the other is referred to as “right”.

[Cam 10]
As shown in FIG. 6 and the like, the cam 10 is provided on a camshaft 15 that extends to the left and right. The camshaft 15 is attached to the cam housing 5 as shown in FIG. The cam housing 5 includes a cam support 5c projecting from the cylinder head, and a cam cap 5a and a block 5b attached on the cam support 5c. The cam shaft 15 is rotatably supported by the cam support 5c and the cam cap 5a. The camshaft 15 rotates once every time the internal combustion engine rotates twice. The cam 10 includes a base circle 11 and a nose 12 protruding from the base circle 11. The camshaft 15 is not provided with a pausing cam having a circular cross-sectional shape that contacts the output arm 30 as shown in the conventional examples 1 and 2. And the block 5b is provided in the left of the rear part of both the arms 20 and 30, as shown in FIG. And the block 5b is provided with the latching pin hole 6 opened on the right side.

[Input arm 20]
As shown in FIG. 8 and the like, the input arm 20 is swingably supported by the rocker shaft 19 by inserting a cylindrical base portion through the rocker shaft 19. The rocker shaft 19 is a pipe-shaped shaft extending in the left-right direction. And the roller 21 contact | abutted to the cam 10 is attached to the front part which protruded ahead from the base part of the input arm 20 rotatably. Further, as shown in FIG. 4 and the like, a lost motion mechanism 29 that urges the input arm 20 against the cam 10 is in contact with a rear portion protruding rearward from the base portion of the input arm 20. The lost motion mechanism 29 includes a body 29a and a lifter 29c, and a lost motion spring 29b that is installed in the body 29a and biases the lifter 29c toward the rear portion of the input arm 20. As shown in FIG. 8 and the like, a cylindrical storage pin 22 that extends to the left and right is attached to the rear portion of the input arm 20 so as to protrude leftward from the left side surface of the rear portion of the input arm 20. The cylindrical hole of the storage pin 22 constitutes the input side pin hole 25. The lower surface of the protruding portion (left portion) of the storage pin 22 constitutes the contact portion 23. A notch 28 that is recessed rightward from the left side surface is provided at the base of the input arm 20 so as to reach the inner peripheral surface from the outer peripheral surface. In the following, when the base circle 11 of the cam 10 abuts against the roller 21 as shown in FIG. 4a or the like is referred to as “base circle”, and the nose 12 of the cam 10 is a roller as shown in FIG. 4b or the like. The time of contact with 21 is referred to as “nose”.

[Output arm 30]
As shown in FIG. 7 and the like, the output arm 30 is divided into a first arm 30A and second arms 30B and 30B. The first arm 30 </ b> A is provided on the left side of the input arm 20, and is supported by the rocker shaft 19 so as to be swingable by having a cylindrical base portion fitted on the rocker shaft 19. As shown in FIG. 8 and the like, a sleeve 31 that protrudes to the right and enters between the inner peripheral surface of the base of the input arm 20 and the outer peripheral surface of the rocker shaft 19 protrudes from the base of the first arm 30A. Has been. On the inner peripheral surface of the sleeve 31, there is provided a first helical spline 34a that is twisted in one direction and turns in one of the swing directions as it advances to the left. The sleeve 31 is provided with a through hole 38 penetrating from the outer peripheral surface to the inner peripheral surface. And the output side pin hole 35 penetrated in the left-right direction is provided in the rear part which protruded back from the base part of 30 A of 1st arms, as shown in FIG. The right end portion of the output side pin hole 35 is a large-diameter portion 35a having a larger diameter than other portions. Further, as shown in FIG. 8 and the like, the abutting portion 23 of the input arm 20 (the lower surface of the protruding portion of the storage pin 22) is applied to the right side surface of the rear portion of the first arm 30A. A contacted portion 32 that comes into contact is projected. A locked projection 33a and a pin contact projection 33b project from the left side surface of the rear portion of the first arm 30A.

  The second arms 30B and 30B are provided on both the left and right sides of the first arm 30A as shown in FIG. The left and right second arms 30 </ b> B are swingably supported on the rocker shaft 19 by fitting a cylindrical base portion to the rocker shaft 19. Further, as shown in FIG. 4 and the like, a second helical spline 34b twisted in the other direction is provided on the inner peripheral surface of the base of each second arm 30B. Yes. And the front part which protruded ahead from the base part of each 2nd arm 30B comprises the output nose 39. FIG. The output nose 39 presses the valve 7 via the intervening arm 60 to drive the valve 7. The intervening arm 60 is supported by a lash adjuster 65 so as to be swingable. In the following, among the swinging sections of the output arm 30, a section in which the valve 7 is opened by the output nose 39 is referred to as a “valve opening section”, and a section in which the valve 7 is not opened is referred to as a “valve closing section”. Of the swinging direction of the output arm 30, the direction on the side where the valve 7 is opened is referred to as “lift direction”, and the opposite direction is referred to as “return direction”.

[Lift amount changing device 40]
As shown in FIG. 8 and the like, the lift amount changing device 40 includes a slider gear 43, a control shaft 41, and an actuator (not shown). The slider gear 43 is a cylindrical member and is interposed between the inner peripheral surface of the output arm 30 (first arm 30A and second arms 30B, 30B) and the outer peripheral surface of the rocker shaft 19. The slider gear 43 includes a first helical spline 43a meshing with the first helical spline 34a and second helical splines 43b and 43b meshing with the second helical splines 34b and 34b on the outer peripheral surface. The control shaft 41 is a shaft extending in the left-right direction, and is inserted inside the pipe-shaped rocker shaft 19 so as to be slidable in the left-right directions D1, D2. The control shaft 41 is engaged with the slider gear 43 via an engagement pin (not shown) so as to be displaced together in the left and right directions D1 and D2. More specifically, the engaging pin (not shown) passes through a long hole (not shown) extending through the rocker shaft 19 and extending left and right, and one end of the engaging pin (not shown) is attached to the control shaft 41 along with it. It is engaged so as to be displaced in the directions D1 and D2, and the other end thereof is displaced together with the slider gear 43 in the left and right directions D1 and D2 and allows relative oscillation in the circumferential direction. Is engaged. The engaging pin (not shown) is attached from the notch 28 of the input arm 20 and the through hole 38 of the output arm 30. The actuator (not shown) displaces the slider gear 43 in the left and right directions D1 and D2 with respect to the output arm 30 by displacing the control shaft 41 in the left and right directions D1 and D2. Thereby, the relative angle of the swinging direction of the second arms 30B and 30B with respect to the first arm 30A is changed by the meshing of the helical splines. Thereby, the lift amount of the valve 7 in the driving state is changed. The lift amount at the reference point is adjusted between the first arm 30A and the input arm 20, between the second arms 30B and 30B and the cam housings 5 and 5, and so on. By interposing 47, 48, 49, the first arm 30A and the second arms 30B, 30B are adjusted in position to the left and right.

[Switching locking device 50]
As shown in FIG. 1 and the like, the switching locking device 50 includes three pins 51, 52, 53 including a switching pin 51, an interposition pin 52, and a locking pin 53, and three pins 51, 52, 53. And a displacement device 56 for displacing in the left and right directions D1 and D2. A portion including the switching pin 51 of the switching locking device 50 constitutes a switching device 50A that switches between a driving state for driving the valves 7 and 7 and a resting state for stopping the driving. The portion including the locking pin 53 of the switching locking device 50 constitutes a locking device 50B that locks the output arm 30 to the cam housing 5 when in a resting state and releases the locking when in a driving state. ing.

  The switching pin 51 is provided in the input side pin hole 25, and the outer diameter of the front end portion 51 a (left end portion) is slightly smaller than the inner diameter of the large diameter portion 35 a of the output side pin hole 35. As shown in FIG. 1a, when the switching pin 51 is displaced to the left D1, the distal end portion 51a of the switching pin 51 enters the large diameter portion 35a of the output side pin hole 35, that is, the switching pin 51 is When arranged at the connecting position P1 across the input side pin hole 25 and the output side pin hole 35, both arms 20 and 30 are connected. On the other hand, as shown in FIG. 1b, when the switching pin 51 is displaced to the right D2, the distal end portion 51a of the switching pin 51 retreats from the large diameter portion 35a of the output side pin hole 35, that is, the switching pin 51 is When arranged at the non-connection position P <b> 2 that does not straddle between the input side pin hole 25 and the output side pin hole 35, the connection between the arms 20 and 30 is released.

  The locking pin 53 is provided in the locking pin hole 6 of the cam housing 5 (block 5b) so as to protrude rightward. A locking hole 53a that is recessed leftward is formed in the right end surface. The inner diameter of the locking hole 53 a is larger than the outer diameter of the locked projection 33 a of the output arm 30. Then, as shown in FIG. 1b, when the locking pin 53 is displaced to the right D2, the locking hole 53a of the locking pin 53 is disengaged from the locked projection 33a of the output arm 30 (first arm 30A). The output arm 30 is locked to the cam housing 5 when the locking arm Q2 is disposed. However, at this time, a clearance C is formed between the inner peripheral surface of the locking hole 53a and the outer peripheral surface of the locked projection 33a. Therefore, within the range of the clearance C, the swing of the output arm 30 with respect to the cam housing 5 is allowed. Therefore, the output arm 30 is held so as to be able to swing within the clearance C within a predetermined holding section M within the valve closing section. At this time, in a state where no external force is applied to the output arm 30, the output arm 30 is arranged on the most lift direction side (the valve opening section side) in the holding section M with the weight of the output noses 39, 39. On the other hand, as shown in FIG. 1 a, when the locking pin 53 is displaced to the left D <b> 1, the output arm 30 with respect to the cam housing 5 is positioned at the non-locking position Q <b> 1 where the above-described external fitting is released. The lock is released.

  The interposition pin 52 is provided in the output side pin hole 35. In the case of a base circle or the like, the right end surface comes into contact with the switching pin 51 and the left end surface comes into contact with the locking pin 53. Therefore, the interposition pin 52 is interposed between the switching pin 51 and the locking pin 53.

  The displacement device 56 includes a spring 57 and a hydraulic chamber 58. The spring 57 is installed in the input side pin hole 25 and urges the right end surface of the switching pin 51 to the left D1. The hydraulic chamber 58 is provided in the locking pin hole 6 and urges the left end surface of the locking pin 53 to the right D2 by hydraulic pressure. The hydraulic chamber 58 is supplied with hydraulic pressure from an oil passage (not shown) provided in the cam housing 5.

  When the driving state is to be set, as shown in FIG. 1a, the hydraulic pressure in the hydraulic chamber 58 is lowered, and the urging force of the spring 57 displaces the three pins 51, 52, 53 to the left D1 by the ball thrust. Let The displacement to the left D1 stops when the left end surface of the switching pin 51 comes into contact with the bottom surface of the large diameter portion 35a of the output side pin hole 35. Thereby, the switching pin 51 is arranged at the coupling position P1, and the locking pin 53 is arranged at the non-locking position Q1. Thereby, both arms 20 and 30 are connected, and the locking of the first arm 30A with respect to the cam housing 5 is released. Therefore, as shown in FIG. 4, both arms 20 and 30 come to swing together. Therefore, the valves 7 and 7 are driven.

  On the other hand, when it should be in a resting state, as shown in FIG. 1b, by increasing the hydraulic pressure of the hydraulic chamber 58, the three pins 51, 52, 53 are displaced to the right D2 by the ball thrust. The displacement to the right D2 stops when the right end surface of the locking pin 53 comes into contact with the left side surface of the first arm 30A. Thereby, the switching pin 51 is disposed at the non-connection position P2, and the locking pin 53 is disposed at the locking position Q2. Accordingly, the connection between the arms 20 and 30 is released, and the first arm 30 </ b> A is locked to the cam housing 5. Therefore, as shown in FIG. 5, the input arm 20 swings and the output arm 30 is locked to the cam housing 5 (held in the holding section M). Therefore, the driving of the valves 7 and 7 is stopped.

  Specifically, the driving state is switched to the resting state as follows. That is, when the hydraulic pressure in the hydraulic chamber 58 rises to the base circle, the driving state shown in FIG. 1a is directly switched to the resting state shown in FIG. 1b. On the other hand, when the hydraulic pressure in the hydraulic chamber 58 rises during the nose, it switches as follows. That is, at the time of the nose shown in FIG. 2a, a force in the right direction D2 is applied to the locking pin 53 by the hydraulic pressure of the hydraulic chamber 58, but the locking pin 53 has a right end surface on the locked protrusion 33a or pin contact protrusion. Since it hits the left end face of 33b, it does not displace to the right D2. Therefore, both arms 20 and 30 continue to swing in a connected state. Therefore, the output arm 30 slides along the right end surface of the locking pin 53. Then, immediately before the base circle at the nose, the position of the locked protrusion 33a of the output arm 30 is aligned with the position of the locking hole 53a of the locking pin 53, as shown in FIG. The aligned state continues until immediately after the base circle after the subsequent base circle due to the relationship that the inner diameter of the locking hole 53a is larger than the outer diameter of the locked projection 33a. Therefore, during that time (such as during the base circle), as shown in FIG. 3c, the three pins 51, 52, 53 are displaced to the right D2. As a result, the driving state shown in FIG. 1a is switched to the resting state shown in FIG. 1b.

  In addition, switching from the resting state to the driving state is performed as follows. That is, when the hydraulic pressure in the hydraulic chamber 58 drops to the base circle, the operation is switched from the rest state shown in FIG. 1b to the drive state shown in FIG. 1a. On the other hand, when the hydraulic pressure in the hydraulic chamber 58 drops at the time of the nose, it switches as follows. That is, during the nose shown in FIG. 3a, a force to the left D1 is applied to the switching pin 51 by the urging force of the spring 57, but the left end surface of the switching pin 51 hits the right side of the first arm 30A. There is no displacement in D1. For this reason, the input arm 20 continues to swing. Therefore, the left end surface of the switching pin 51 slides along the right side surface of the first arm 30A. Then, immediately before the base circle at the time of nose shown in FIG. 3b, the contact portion 23 of the input arm 20 lifts to the contacted portion 32 of the output arm 30 located on the lift direction side in the holding section M. Push down in the return direction by contacting from the direction side. Then, the contact state, which is the state of contact, continues until immediately after the base circle time after the subsequent base circle time. That is, in the contact state, the output arm 30 swings in the holding section M together with the input arm 20 by the clearance C. In the contact state, the position of the input side pin hole 25 is aligned with the position of the output side pin hole 35. Therefore, in the contact state, as shown in FIG. 3c, the three pins 51, 52, 53 are displaced to the left D1. As a result, the driving state shown in FIG. 1a is switched from the resting state shown in FIG. 1b.

According to the first embodiment, the following effects can be obtained.
[A] Since the first arm 30A is held in the holding section M by the switching locking device 50 (locking pin 53) in the resting state, the resting position of the first arm 30A is fixed and in the resting state. The output arm 30 does not flutter.

[B] Since the inner diameter of the locking hole 53a is larger than the outer diameter of the locked protrusion 33a (clearance C is formed), in the driving state, as described above, the locked hole 53a is covered during the period from immediately before to immediately after the base circle. The position of the locking projection 33a is aligned with the position of the locking hole 53a. Therefore, variation in the swing of the first arm 30A in the driving state can be absorbed in the clearance C. Therefore, switching from the driving state to the resting state (disconnection) can be performed reliably.
[C] Switching from the driving state to the resting state (releasing the connection) is always performed within a period (a period in which the position of the locked protrusion 33a is aligned with the position of the locking hole 53a) immediately before and after the base circle. Therefore, the connection is not released in the middle of the nose. Therefore, the output arm 30 does not jump up by the urging force of the valve spring 8.
[D] In the resting state, since the output arm 30 swings together with the input arm 20 in the contact state immediately before and after the base circle, the positioning accuracy of the input arm 20 with respect to the output arm 30 in the contact state Will improve. Therefore, the input-side pin hole 25 and the output-side pin hole 35 can be reliably aligned in the contact state, and by doing so, the three pins 51, 52, 53 can be reliably displaced. Therefore, switching (connection) from the resting state to the driving state can be performed reliably.

[E] Since the locking pin 53 and the interposition pin 52 do not receive a load (connection force) from both the arms 20 and 30, they can be made thin.
[F] In the second half of the nose in the driving state (when swinging in the return direction) (FIG. 2 b and before), the contact portion 23 of the input arm 20 presses the contacted portion 32 of the output arm 30. Therefore, the switching pin 51 does not receive a load (coupling force) from both arms 20 and 30. Therefore, the burden on the switching pin 51 is reduced.
[G] In either the driving state (low pressure) or the resting state (high pressure), the first arm 30A is biased to the left side surface of the input arm 20 by the right end surface of the locking pin 53 by the hydraulic pressure of the hydraulic chamber 58. Thus, the gap between the first arm 30A and the input arm 20 can be eliminated automatically.
[H] In addition to switching between the driving state and the resting state by the switching locking device 50, the lift amount changing device 40 also changes the lift amount of the valve 7 in the driving state, so that the engine performance is further improved. .

  The variable valve mechanism 2 of the second embodiment shown in FIG. 9 differs from the variable valve mechanism 1 of the first embodiment in the following points and is the same in other points. That is, the locking pin 53 does not include the locking hole 53a on the right end surface. A second large diameter portion 35b having a larger diameter than the front portion is provided at the left end portion of the output side pin hole 35. The inner diameter of the second large diameter portion 35 b is larger than the outer diameter of the right end portion of the locking pin 53. And the latching protrusion 33a and the pin contact protrusion 33b are not provided in the left side surface of the 1st arm 30A.

  As shown in FIG. 9b, the locking position Q2 is a position where the right end portion of the locking pin 53 enters the second large diameter portion 35b when the locking pin 53 is displaced to the right D2, that is, The locking pin 53 is a position straddling between the locking pin hole 6 and the output side pin hole 35. And the displacement to the right D2 here stops, when the right end surface of the latching pin 53 contact | abuts to the bottom face of the 2nd large diameter part 35b. At this time, a clearance C is formed between the outer peripheral surface of the right end portion of the locking pin 53 and the inner peripheral surface of the second large diameter portion 35b.

  On the other hand, as shown in FIG. 9a, the non-locking position Q1 is a position where the right end portion of the locking pin 53 is retracted from the second large diameter portion 35b when the locking pin 53 is displaced to the left D1. The locking pin 53 does not straddle between the locking pin hole 6 and the output side pin hole 35. Also according to the second embodiment, the effects A to H can be obtained.

  The variable valve mechanism 3 of the third embodiment shown in FIG. 10 is different from the variable valve mechanism 1 of the first embodiment in the following points, and is the same in other points. That is, the first arm 30A and the second arm 30B are connected. Therefore, the output arm 30 is not divided into the first arm 30A and the second arm 30B. The variable valve mechanism 3 does not include the lift amount changing device 40. Therefore, the variable valve mechanism 3 only switches between the resting state and the driving state, and does not change the lift amount of the valve in the driving state. According to the third embodiment, the above effects A to G can be obtained.

The present embodiment can be modified as follows, for example.
[Modification 1]
In the first to third embodiments, the locking pin hole 6 is provided in the block 5b provided separately from the cam support 5c and the cam cap 5a. However, the block 5b is eliminated and the cam support 5c or the cam cap 5a is engaged. A stop pin hole 6 may be provided.

1 Variable valve mechanism (Example 1)
2 Variable valve mechanism (Example 2)
3 Variable valve mechanism (Example 3)
5 cam housing 7 valve 10 cam 11 base circle 12 nose 15 camshaft 20 input arm 23 abutting portion 30 output arm 30A first arm 30B second arm 32 abutted portion 40 lift amount changing device 50 switching locking device 50A switching Device 50B Locking device 51 Switching pin 52 Intervening pin 53 Locking pin 56 Displacement device D1 Left (one direction)
D2 right (other direction)
P1 Connection position P2 Non-connection position Q1 Non-locking position Q2 Locking position M Holding section

Claims (4)

A cam (10) provided on a camshaft (15) rotatably supported by the cam housing (5) and rotated according to the rotation of the internal combustion engine, and an input arm (20) driven by the cam (10) to swing. And an output arm (30) swingably provided in a valve opening section for opening the valve (7) and a valve closing section for closing the valve (7), and the output arm (30) together with the input arm (20). By connecting both arms (20, 30) so that the oscillates, the drive state is switched to drive the valve (7), and the connection is released to stop the drive of the valve (7). In the variable valve mechanism of the internal combustion engine provided with the switching device (50A) for switching to
By locking the output arm (30) to the cam housing (5) during the resting state, the output arm (30) is held within a predetermined holding section (M) in the valve closing section, and when in the driving state, A variable valve mechanism for an internal combustion engine, comprising a locking device (50B) for releasing the locking. The output arm (30) has a first arm (30A) coupled to the input arm (20) in a driving state and a second arm (30B) that swings together with the first arm (30A) to drive the valve (7). ) And divided into
A lift amount changing device (40) for changing the lift amount of the valve (7) in the driven state by changing the relative angle of the swinging direction of the second arm (30B) with respect to the first arm (30A);
The variable valve mechanism for an internal combustion engine according to claim 1, wherein the output arm (30) is locked by the locking device (50B) by locking the first arm (30A) to the cam housing (5). The switching device (50A) and the locking device (50B) are incorporated in the switching locking device (50),
The switching locking device (50) includes a switching pin (51) provided to be displaceable between a connecting position (P1) for connecting the arms (20, 30) and a non-connecting position (P2) for releasing the connection. The locking pin (53) provided to be displaceable between a locking position (Q2) for locking the output arm (30) to the cam housing (5) and a non-locking position (Q1) for releasing the locking. And an interposition pin (52) interposed between the switching pin (51) and the locking pin (53), and a displacement device (56),
The displacement device (56) displaces the switching pin (51), the interposition pin (52), and the locking pin (53) in one direction (D1) by ball striking, thereby moving the switching pin (51) to the coupling position (P1). ), The locking pin (53) is disposed at the non-locking position (Q1), and is displaced in the other direction (D2) opposite to the one direction (D1) by the ball hitting. 51) is arranged at the non-connection position (P2), and the locking pin (53) is arranged at the locking position (Q2).
The portion including the switching pin (51) of the switching locking device (50) constitutes the switching device (50A), and the portion including the locking pin (53) of the switching locking device (50) is the locking device ( The variable valve mechanism for an internal combustion engine according to claim 1 or 2, wherein said variable valve mechanism is constituted by 50B). The holding of the output arm (30) by the locking device (50B) allows the output arm (30) to swing within the holding section (M).
In the resting state, the nose (12) provided on the input arm (20) is provided immediately before the base circle on which the base circle (11) of the cam (10) acts at the nose on which the nose (12) of the cam (10) acts. The contact state where the contact portion (23) is in contact with the contacted portion (32) provided on the output arm (30) from the swinging direction side and the contact portion is in contact with the base circle. Continuing until just after the base circle passed, and in the contact state, the output arm (30) is configured to swing together with the input arm (20) in the holding section (M),
The internal combustion engine according to any one of claims 1 to 3, wherein the switching device (50A) switches from the resting state to the driving state by connecting both arms (20, 30) in the contact state. Variable valve mechanism.

Images