JP4469341B2 - Variable valve mechanism - Google Patents

Description

  The present invention relates to a variable valve mechanism that controls valve characteristics in accordance with the operating state of an internal combustion engine.

  2. Description of the Related Art Conventionally, a variable valve mechanism that uses a link to control the lift amount, operating angle, and opening / closing timing of a valve is known. For example, the variable valve mechanism 170 of Patent Document 1 shown in FIG. 22 includes a camshaft 171 that is rotated by a crankshaft of an internal combustion engine. A rotating cam 172 is fixed on the camshaft 171 so as to be integrally rotatable, and a swing cam 174 that drives the valve 181 via a valve lifter 173 is supported so as to be relatively rotatable.

A swing arm 176 is supported via a control cam 177 on a control shaft 175 parallel to the cam shaft 171. The input end of the swing arm 176 is connected to the rotary cam 172 via a ring-shaped link 178, and the output end of the swing arm 176 is connected to the swing cam 174 via a rod-shaped link 179. The control shaft 175 is driven by an actuator, and the displacement amount (swing angle) of the swing arm 176 is changed according to the operating state of the internal combustion engine by the eccentric rotation of the control cam 177.
JP-A-11-324625

  However, in the conventional variable valve mechanism 170, the variable device 180 that changes the amount of displacement of the swing arm 176 constitutes a closed-loop power transmission system including a pair of links 178 and 179. Accordingly, the rotating cam 172 applies a large load to the variable device 180. In order to rotate the control cam 177 of the variable device 180 against this load, a large torque is required to drive the control shaft 175, and it is necessary to use a large and high output motor for the actuator. In addition, the high output of the actuator increases the power loss of the internal combustion engine, which adversely affects fuel consumption.

  An object of the present invention is to provide a variable valve mechanism that solves the above problems, reduces the load acting on the variable device, can accurately change the displacement amount of the displacement cam with a small actuator, and is useful for improving the fuel consumption of the internal combustion engine. There is to do.

In order to solve the above problems, the present invention provides a rotating cam provided on a camshaft, a displacement cam that engages and displaces the rotating cam, and a valve operating member that drives the valve following the displacement cam. And a variable valve mechanism including a variable device that changes the displacement amount of the displacement cam according to the operating state of the internal combustion engine, the variable device can be rotated on the support shaft at the variable arm and the bifurcated end of the variable arm A contact that contacts the cam surface of the displacement cam, and a pair of rings that are mounted on the support shaft so as to be located on both sides of the contact and inside the tip bifurcated portion; a variable cam a variable arm to drive varying the initial contact position between the contact and the cam surface, and an actuator for driving the variable cam, a pair of guide portions across the contacts is projected downward, it is formed in the guide portion The downward guide surface contacts the ring. Characterized in that it comprises a guide member for guiding the contact between the cam surface.

Here, the following means can be adopted for the rotating cam.
(1) The rotating cam is provided with a base portion that keeps the valve lift amount to zero within a predetermined angle range of the camshaft, and a nose portion that increases the valve lift amount within the remaining angle range.
(2) Use an eccentric cam whose center is offset from the axis of the camshaft.

With respect to the displacement cam, the following means can be employed.
(3) The displacement cam is disposed in a region surrounded by the camshaft, the valve operating member, and the variable device.
(4) The displacement cam is provided with an input portion that engages with the rotating cam, an output portion that engages with the valve member, and a cam surface that contacts the contact of the variable device.
(5) The displacement cam is disposed above the cylinder head, the output portion is provided downward, and the cam surface is provided upward.
(6) The output portion of the displacement cam is pivotally connected to the valve operating member.
(7) Provide a sliding surface in sliding contact with the valve member at the output portion of the displacement cam.

The following means can be adopted for the valve operating member.
(8) Use a rocker arm that swings around the base end as a valve member.
(9) Use a swing arm that swings around the intermediate part as a valve member.
(10) Use a cup-type lifter that can move linearly in the axial direction of the valve as the valve operating member.

Regarding the variable device, the following means can be adopted.
(11) Use a rotating body for the contact that contacts the cam surface of the displacement cam.
(12) A cam that drives the contact is used as the variable member that changes the initial contact position.
(13) A cam that drives a displacement cam is used as the variable member that changes the initial contact position.
(14) A variable member is provided on a control shaft parallel to the camshaft, and the variable member is driven by the actuator via the control shaft.
(15) The guide member is fixed to the housing of the variable valve mechanism at a position above the cam surface of the displacement cam, and a downward guide surface facing the cam surface is formed on the guide member.

Moreover, regarding the variable device, the following configuration can be preferably adopted.
(16) The variable member that changes the initial contact position includes a variable arm that rotatably supports the contact, a variable cam that drives the variable arm, and a shim that is interposed between the variable arm and the variable cam. Provide the cam on the control shaft parallel to the camshaft, and connect the control shaft to the actuator.

  According to the variable valve mechanism of the present invention, the amount of displacement of the displacement cam can be accurately controlled according to the operating state of the internal combustion engine by changing the initial contact position between the cam surface of the displacement cam and the contact. . At this time, since the contact is guided between the guide member and the cam surface, the power of the camshaft is distributed to the guide member side and the variable member side with the contact as a branch point. Therefore, the force for driving the variable member is small, and there is an effect that a small and low output device can be used for the actuator. Further, by reducing the output of the actuator, there is an effect that the power loss of the internal combustion engine is reduced and it is possible to contribute to the improvement of fuel consumption.

  Furthermore, when a shim is interposed between the variable arm that supports the contact and the variable cam on the control shaft, the relative position between the displacement cam and the variable arm can be changed by changing the thickness of the shim. The initial contact position between the cam surface and the contact can be finely adjusted. For this reason, in an internal combustion engine having a plurality of cylinders, there is an effect that variations in valve characteristics between cylinders can be easily suppressed without strictly managing the dimensional accuracy and assembly accuracy of valve operating parts.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1, 7, and 11, the variable valve mechanism (1, 41, 51) of this embodiment includes a rotating cam (13, 43) provided on the camshaft (4) and a rotating mechanism. A displacement cam (5, 52) that engages and displaces the cam, a rocker arm (6) that drives the valve (12) following the displacement cam, and the displacement amount of the displacement cam is determined by the internal combustion engine. And a variable device (23, 42) that changes according to the operating state.

The displacement cam is disposed in a region surrounded by the camshaft, the rocker arm, and the variable device above the cylinder head ( 3 ). The variable device includes a contact (24) that contacts the upward cam surface (17, 53) of the displacement cam, a variable cam (27, 44) that changes an initial contact position between the contact and the cam surface, and a variable cam. And a guide member (31) having a downward guide surface (33) for guiding the contact between the contact surface and the cam surface.

  1 to 6 show a variable valve mechanism 1 according to a first embodiment. The variable valve mechanism 1 is used in an intake system of an automobile gasoline engine. However, the same mechanism can be applied to the exhaust system of a gasoline engine. As shown in FIGS. 1 to 3, the housing 2 of the variable valve mechanism 1 is installed on the cylinder head 3, and the camshaft 4, the displacement cam 5, the rocker arm 6, and the control shaft 7 are disposed in the housing 2. ing. The camshaft 4 and the control shaft 7 are supported in parallel at a high place away from the cylinder head 3, the rocker arm 6 is provided at a low place near the cylinder head 3, and the displacement cam 5 is connected to the camshaft 4 and the control shaft 7. It is arranged in a region surrounded by the rocker arm 6.

  The base end of the rocker arm 6 is supported by a pivot 9, and the pivot 9 is screwed to a holder 10 fixed to the housing 2 so that the height can be adjusted. A pressing portion 11 is provided at the tip of the rocker arm 6, and the rocker arm 6 swings up and down around the pivot 9 to open and close a valve (intake valve) 12 by the pressing portion 11. A rotating cam 13 is fixed on the camshaft 4 and is rotationally driven integrally with the camshaft 4 by an engine crankshaft (not shown). The rotary cam 13 is provided with a base portion 13a that keeps the lift amount of the valve 12 at zero within a predetermined angle range, and a nose portion 13b that increases the valve lift amount in the remaining angle range.

  The displacement cam 5 is provided with a downward output portion 15, a lateral input portion 16, and an upward cam surface 17. The output unit 15 is rotatably connected to an intermediate part of the rocker arm 6 by a connecting shaft 18. A roller 19 that engages with the rotating cam 13 is supported on the input unit 16 by a roller shaft 20. The cam surface 17 is formed with an equal radius portion 17 a included in a base circle 21 centered on the axis of the connecting shaft 18 and a lift portion 17 b that rises obliquely outward from the base circle 21. The displacement cam 5 is displaced up and down in accordance with the profile of the rotating cam 13 and the cam surface 17, and the rocker arm 6 follows the displacement cam 5 to open and close the valve 12.

  A variable device 23 that changes the displacement amount of the displacement cam 5 per one rotation of the rotary cam 13 in accordance with the operating state of the engine is provided around the control shaft 7. The variable device 23 includes a contact 24 that contacts the cam surface 17 of the displacement cam 5. The contact 24 is rotatably supported by a support shaft 26 at a tip bifurcated portion 25a of an arm 25, and a base end hole 25b of the arm 25 is externally fitted to the variable cam 27 so as to be relatively rotatable. The variable cam 27 is fixed on the control shaft 7 in an eccentric state, and one end of the control shaft 7 is connected to a hydraulic or electric actuator 28. The actuator 28 is controlled by a control device (not shown) according to the operating state of the engine, the variable cam 27 drives the arm 25 left and right, changes the initial contact position between the contact 24 and the cam surface 17, and the displacement cam The displacement amount of 5 is changed.

  A pair of rings 30 (see FIG. 3) are inserted on the support shaft 26 of the contactor 24 so as to be positioned on both sides of the contactor 24. A guide member 31 is fixed to the upper surface of the housing 2, and a pair of guide portions 32 straddling the contact member 24 is provided on the guide member 31 so as to protrude downward. In the guide portion 32, a downward guide surface 33 that contacts the ring 30 is formed along an arc 34 (see FIG. 2) concentric with the base circle 21. When the initial contact position is changed and when the camshaft 4 is rotated, the guide surface 33 of the guide member 31 guides the contact 24 with the cam surface 17. As shown in FIG. 3, bushes 35, 36, and 37 are inserted into the connecting shaft 18, the roller shaft 20, and the support shaft 26, respectively.

  Next, the operation of the variable valve mechanism 1 will be described with reference to FIGS. FIG. 4 shows a state when the displacement cam 5 is operated with a minimum displacement amount. At this time, the variable cam 27 of the variable device 23 pulls the contact 24 toward the control shaft 7, and sets the initial contact position P between the cam surface 17 of the displacement cam 5 and the contact 24 to the start end side of the constant radius portion 17a. ing. When the rotating cam 13 rotates in this state, as shown in (a), during the period in which the base portion 13a is engaged with the roller 19, the displacement cam 5 does not swing, and the rocker arm 6 stops. Valve 12 is held in the closed position.

  Then, as shown in (b), when the apex of the nose portion 13b is engaged with the roller 19, the lift portion 17b of the cam surface 17 comes into contact with the contact 24, and the displacement cam 5 faces downward with the gradient of the lift portion 17b. Displaces downward under force. However, since the initial contact position P is set at the start end side of the constant radius portion 17a, the contact range between the lift portion 17b and the contact 24 is limited, the displacement cam 5 is slightly displaced, and the rocker arm 6 is at the minimum angle. Swing with. Therefore, as shown by the curve (A) in FIG. 6, both the valve lift amount and the operating angle are minimized, and the opening timing of the intake valve 12 is controlled late and the closing timing is controlled early. The curve (e) in FIG. 6 shows the lift amount and operating angle of the exhaust valve.

  FIG. 5 shows a state when the displacement cam 5 is operated with the maximum amount of displacement. At this time, the variable cam 27 moves the contact 24 toward the camshaft 4 and changes the initial contact position P toward the end of the constant radius portion 17a. Further, since the contact 24 is guided between the concentric guide surface 33 and the equal radius portion 17a, even if the displacement cam 5 is not pushed down by the power of the variable cam 27 and the initial contact position P changes, the rocker arm The initial phase of 6 does not change. For this reason, as shown in (a), during the period in which the base portion 13a is engaged with the roller 19, both the displacement cam 5 and the rocker arm 6 are stationary, and the valve 12 is held in the closed position.

  Then, as shown in (b), when the apex of the nose portion 13b is engaged with the roller 19, the terminal end side of the lift portion 17b contacts the contact 24, and the displacement cam 5 corresponds to the effective length of the lift portion 17b. The distance greatly displaces downward, and the rocker arm 6 swings at the maximum angle. Therefore, as shown by the curve (b) in FIG. 6, both the valve lift amount and the operating angle are maximized, and the opening timing of the intake valve 12 is controlled earlier and the closing timing is controlled later. Therefore, by changing the initial contact position P between the contactor 24 and the cam surface 17 by the variable device 23, the valve characteristics can be accurately adjusted to an arbitrary intermediate value as shown by the curves (c) and (d) in FIG. Can be controlled.

  By the way, according to the variable device 23 of this embodiment, the contact 24 is guided between the cam surface 17 of the displacement cam 5 and the guide surface 33 of the guide member 31, so that the power of the camshaft 4 is driven by the contact 24. Is distributed to the guide member 31 side and the variable cam 27 side. For this reason, the load acting on the variable cam 27 is halved, and the torque required to rotate the variable cam 27 is reduced. Therefore, a small and low output hydraulic or electric device can be used for the actuator 28, and the power loss of the engine can be suppressed to improve fuel efficiency. Further, since the cam surface 17 is provided upward, the rocker arm 6 is integrally connected to the lower side of the displacement cam 5 so that both can be compactly installed on the cylinder head 3 and the rocker arm 6 in the high-speed rotation range can be installed. It becomes possible to improve the cam followability.

  7 to 10 show the variable valve mechanism 41 of the second embodiment. As shown in FIGS. 7 and 8, in the variable valve mechanism 41, the camshaft 4 and the control shaft 7 are arranged at positions opposite to those in the first embodiment. The arm 25 that supports the contactor 24 is supported by a rotating cam 43 on the camshaft 4. An eccentric cam whose center is offset from the axis of the camshaft 4 is used for the rotating cam 43.

  The variable cam 44 of the variable device 42 is fixed on the control shaft 7 and includes a base portion 44 a and a nose portion 44 b that engage with the roller 19. The variable cam 44 is driven by the actuator 28 via the control shaft 7, and the displacement cam 5 is swung around the connecting shaft 18 to change the initial contact position between the cam surface 17 and the contact 24. ing. The other structure is the same as that of Example 1, and the same member was shown with the same code | symbol in drawing.

  The variable valve mechanism 41 operates as shown in FIGS. When the displacement cam 5 is operated with the minimum displacement amount, as shown in FIG. 9, the variable cam 44 of the variable device 42 engages the base portion 44a with the roller 19 and swings the displacement cam 5 toward the control shaft 7 side. Thus, the initial contact position P between the cam surface 17 and the contactor 24 is set to the start end side of the constant radius portion 17a. When the rotating cam 43 rotates eccentrically in this state, as shown in FIG. 4A, both the displacement cam 5 and the rocker arm 6 are stationary while the contactor 24 is in contact with the constant radius portion 17a.

  As shown in (b), when the contactor 24 exceeds the constant radius portion 17a and contacts the lift portion 17b, the displacement cam 5 receives a downward force due to the gradient of the lift portion 17b and is displaced downward. However, since the initial contact position P is set on the start end side of the constant radius portion 17a, the contact range between the lift portion 17b and the contact 24 is limited, the displacement cam 5 is slightly displaced, and the rocker arm 6 is minimized. Swings at an angle. Therefore, as shown by the curve (A) in FIG. 6, both the valve lift amount and the operating angle are minimized, and the opening timing of the intake valve 12 is controlled late and the closing timing is controlled early.

  When the displacement cam 5 is operated with the maximum amount of displacement, as shown in FIG. 10, the variable cam 44 engages the nose portion 44b with the roller 19, and the displacement cam 5 is swung to the camshaft 4 side, thereby initial contact. The position P is changed to the end side of the equal radius portion 17a. In this state, with the eccentric rotation of the rotating cam 43, the contactor 24 is guided by the guide surface 33 of the guide member 31, and reciprocates between the constant radius portion 17a and the lift portion 17b. And as shown to (a), when the contactor 24 contacts the equal radius part 17a, both the displacement cam 5 and the rocker arm 6 stand still, and the valve | bulb 12 is hold | maintained in a closed position.

  On the other hand, as shown in (b), when the contactor 24 comes into contact with the end side of the lift portion 17b, the displacement cam 5 is greatly displaced downward, and the rocker arm 6 swings at the maximum angle. Therefore, as shown by the curve (b) in FIG. 6, both the valve lift amount and the operating angle are maximized, and the opening timing of the intake valve 12 is controlled earlier and the closing timing is controlled later.

  Also with this variable device 42, as with the variable device 23 of the first embodiment, the guide member 31 guides the contact 24 with the cam surface 17, so that part of the power of the camshaft 4 is guided from the contact 24. The load acting on the variable cam 44 can be halved by escaping to the housing 2 side via the member 31, and the actuator 28 can be reduced in size and output. Further, the rocker arm 6 can be integrally connected to the lower side of the displacement cam 5 having the upward cam surface 17 to reduce the installation form and improve the cam followability of the rocker arm 6 in the high-speed rotation range. it can.

  11 to 14 show the variable valve mechanism 51 of the third embodiment. As shown in FIGS. 11 and 12, the variable valve mechanism 51 is different from the first and second embodiments mainly in the configuration of the displacement cam 52. The displacement cam 52 includes a downward output portion 15, a lateral input portion 16, and an upward cam surface 53 that engages with the contact 24. The output unit 15 is separated from the rocker arm 6, and the output unit 15 is provided with a downward sliding surface 54 that is in sliding contact with the upper surface of the rocker arm 6.

  The cam surface 53 is formed with a flat portion 53a that is parallel to the sliding surface 54 and a lift portion 53b that rises obliquely from the flat portion 53a. In accordance with the shape of the cam surface 53, the guide surface 33 of the guide member 31 is formed in a downward flat shape, and the arm 25 of the variable device 23 is provided upside down from the first embodiment. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals in the drawings.

  The variable valve mechanism 51 operates as shown in FIGS. When the displacement cam 5 is operated with a minimum displacement, the variable cam 27 of the variable device 23 moves the contact 24 toward the control shaft 7 as shown in FIG. The contact position P is set to the start end side of the flat portion 53a. When the rotating cam 13 rotates in this state, both the displacement cam 52 and the rocker arm 6 are stationary during the period in which the base portion 13a is engaged with the roller 19, as shown in FIG.

  As shown in (b), when the apex of the nose portion 13 b engages with the roller 19, the displacement cam 52 slides on the rocker arm 6 toward the control shaft 7, and the lift portion 53 b of the cam surface 53 becomes the contact 24. The displacement cam 52 receives a downward force at the gradient of the lift portion 53b and is displaced downward. However, since the initial contact position P is set on the start end side of the flat portion 53a, the contact range between the lift portion 53b and the contact 24 is limited, the displacement cam 52 is slightly displaced, and the rocker arm 6 is at the minimum angle. Swing. Therefore, as shown by the curve (A) in FIG. 6, both the valve lift amount and the operating angle are minimized, and the opening timing of the intake valve 12 is controlled late and the closing timing is controlled early.

  When the displacement cam 52 is operated with the maximum amount of displacement, as shown in FIG. 14, the variable cam 27 slides the contactor 24 toward the camshaft 4 and changes the initial contact position P toward the terminal side of the flat portion 53a. Let At this time, since the contact 24 is guided between the guide surface 33 and the flat portion 53a parallel to each other, even if the displacement cam 52 is not pushed down by the power of the variable cam 27 and the initial contact position P changes, the rocker arm The initial phase of 6 does not change. Therefore, as shown in (a), the displacement cam 52 and the rocker arm 6 are both stationary during the period in which the base portion 13a is engaged with the roller 19.

  Then, as shown in (b), when the apex of the nose portion 13b is engaged with the roller 19, the displacement cam 52 slides toward the control shaft 7 side, and the terminal end side of the lift portion 53b comes into contact with the contactor 24 and is displaced. The cam 52 is greatly displaced downward, and the rocker arm 6 swings at the maximum angle. Therefore, as shown by the curve (b) in FIG. 6, both the valve lift amount and the operating angle are maximized, and the opening timing of the intake valve 12 is controlled earlier and the closing timing is controlled later.

Also with this variable valve mechanism 51, since the guide member 31 guides the contact 24 with the cam surface 53, part of the power of the camshaft 4 is released from the contact 24 toward the guide member 31 and the variable cam. The load acting on the actuator 27 can be halved, and the actuator 28 can be reduced in size and output. Further, since there is provided the upward cam surface 53 and down the sliding surface 54 on the displacement cam 52, by shortening the vertical dimension of the displacement cam 52, the rocker arm 6 is arranged immediately below, both on the cylinder head 3 There is also an advantage that it can be installed in a compact form.

  15 to 19 show a variable valve mechanism 71 of the fourth embodiment. The variable valve mechanism 71 is different from the first, second, and third embodiments mainly in the configuration of the variable device 72. As shown in FIGS. 15 and 16, the variable device 72 is interposed between the variable arm 73 that supports the contactor 24, the variable cam 74 that drives the variable arm 73, and the variable arm 73 and the variable cam 74. And a shim 75. The variable arm 73 is formed in an annular shape, and the contactor 24 and the ring 30 are rotatably supported by the support shaft 26 inside. A spring 76 for urging the variable arm 73 toward the guide member 31 and the variable cam 74 is provided on the upper portion of the housing 2.

  As shown in FIG. 17, two variable cams 74 are fixedly provided on the control shaft 7 for each cylinder. The control shaft 7 is supported by the housing 2 so as to extend between a plurality of cylinders, and is rotated integrally with the variable cam 74 by an actuator 28 (see FIG. 15). The shim 75 is mounted in a concave groove 77 formed on the end surface of the variable arm 73 and is pressed against the cam surface 74 a of the variable cam 74 by the urging force of the spring 76. As the shim 75, a plate-shaped or half-columnar shim can be used.

  In the variable valve mechanism 71 configured as described above, when the valve 12 is opened and closed with the minimum lift amount, the initial contact position P between the displacement cam 5 and the contactor 24 is set by the variable cam 74 as shown in FIG. It is adjusted to the start end (left end) side of the equal radius portion 17a. While the base portion 13a of the rotating cam 13 is engaged with the roller 19, both the displacement cam 5 and the rocker arm 6 are stationary, and the valve 12 is held in the closed position. As shown in FIG. 18B, when the apex of the nose portion 13b is engaged with the roller 19, the displacement cam 5 is slightly displaced downward while swinging toward the control shaft 7 side. Then, the rocker arm 6 swings at the minimum angle to open and close the valve 12 with the minimum lift amount.

  When the valve 12 is opened and closed with the maximum lift amount, as shown in FIG. 19A, the initial contact position P between the displacement cam 5 and the contactor 24 is changed to the end (right end) side of the constant radius portion 17a by the variable cam 74. Adjusted to At this time, since the contact 24 is guided by the guide surface 33 concentric with the constant radius portion 17a, the valve 12 is not affected by the change of the initial contact position P during the period in which the base portion 13a is engaged with the roller 19. Held in the closed position. On the other hand, as shown in FIG. 19B, when the apex of the nose portion 13b is engaged with the roller 19, the displacement cam 5 is greatly displaced downward while swinging toward the control shaft 7 side. Then, the rocker arm 6 swings at the maximum angle to open and close the valve 12 with the maximum lift amount.

  Therefore, also with this variable valve mechanism 71, as in the above embodiments, a part of the power of the camshaft 4 is released from the contactor 24 toward the guide member 31, and the load acting on the variable device 72 is halved. The actuator 28 can be reduced in size and output. Since the shim 75 is interposed between the variable arm 73 and the variable cam 74, the thickness of the shim 75 (t1 <t2 <t3) can be changed as shown in FIG. The initial contact position between the cam surface 17 and the contactor 24 can be finely adjusted by changing the relative position with the arm 73. For this reason, in a multi-cylinder gasoline engine, variations in valve characteristics among cylinders can be easily suppressed without strictly managing the dimensional accuracy and assembly accuracy of valve operating parts, resulting in fuel efficiency, emissions, engine vibration, etc. A favorable effect can be expected.

In addition, this invention is not limited to the said Example, For example, as follows, it can also change suitably in the range which does not deviate from the meaning of invention, and can also be embodied.
(1) As shown in FIG. 20, in the variable device 23 of the first or third embodiment, a variable arm 61 in which a variable member that changes the initial contact position is fixed on the control shaft 7, and the variable arm 61 is a contactor. 24 and a link 62 connected to 24.

(2) As shown in FIG. 21, in the variable valve mechanism 51 of the third embodiment, a cup type lifter 64 as a valve member is slidably inserted into the guide hole 65 of the housing 2 to slide the displacement cam 52. The cup-type lifter 64 should be struck by the moving surface 54.
(3) A T-shaped rocker arm is used as a valve operating member, two valve drive portions are provided at both ends thereof, and a two-valve integrated variable valve mechanism that drives two valves with one rocker arm is configured. thing.

It is a perspective view of the variable valve mechanism which shows Example 1 of this invention. FIG. 2 is a cross-sectional view of the variable valve mechanism according to the first embodiment when viewed from the left in FIG. 1. It is a longitudinal cross-sectional view of the variable valve mechanism of Example 1. It is a mechanism figure which shows an effect | action when the valve lift amount is minimized in the variable valve mechanism of Embodiment 1. It is a mechanism figure which shows an effect | action when maximizing valve lift amount in the variable valve mechanism of Example 1. FIG. It is a characteristic view which shows the relationship between a valve lift amount and a working angle. It is a perspective view of the variable valve mechanism which shows Example 2 of this invention. FIG. 8 is a cross-sectional view of the variable valve mechanism according to the second embodiment when viewed from the left in FIG. 7. It is a mechanism figure which shows an effect | action when the valve lift amount is minimized in the variable valve mechanism of Example 2. It is a mechanism figure which shows an effect | action when maximizing valve lift amount in the variable valve mechanism of Example 2. FIG. It is a perspective view of the variable valve mechanism which shows Example 3 of this invention. FIG. 12 is a cross-sectional view of the variable valve mechanism according to the third embodiment when viewed from the left in FIG. 11. It is a mechanism figure which shows an effect | action when the valve lift amount is minimized in the variable valve mechanism of Example 3. It is a mechanism figure which shows an effect | action when maximizing valve lift amount in the variable valve mechanism of Example 3. FIG. It is a perspective view of the variable valve mechanism which shows Example 4 of this invention. It is sectional drawing which looked at the variable valve mechanism of Example 4 from the left side of FIG. FIG. 6 is a layout diagram of a variable valve mechanism of Embodiment 4 in a multi-cylinder gasoline engine. It is a mechanism figure which shows an effect | action when the valve lift amount is minimized in the variable valve mechanism of Example 4. It is a mechanism figure which shows an effect | action when maximizing the valve lift amount in the variable valve mechanism of Example 4. It is sectional drawing of the variable valve mechanism which shows the example of a change of this invention. It is sectional drawing of the variable valve mechanism which shows another modification of this invention. It is sectional drawing which shows the conventional variable valve mechanism.

Explanation of symbols

1 Variable valve mechanism (Example 1)
4 Camshaft 5 Displacement Cam 6 Rocker Arm 7 Control Shaft 12 Valve 13 Rotating Cam 17 Cam Surface 23 Variable Device 24 Contact 27 Variable Cam 28 Actuator 31 Guide Member 33 Guide Surface 41 Variable Valve Mechanism (Embodiment 2)
42 Variable Device 43 Rotating Cam 44 Variable Cam 51 Variable Valve Mechanism (Embodiment 3)
52 Displacement Cam 53 Cam Surface 61 Variable Arm 62 Link 64 Cup Type Lifter 71 Variable Valve Mechanism (Embodiment 4)
72 Variable Device 73 Variable Arm 74 Variable Cam 75 Shim P Initial Contact Position

Claims (2)

A rotating cam provided on the camshaft; a displacement cam that engages and displaces the rotating cam; a valve member that drives the valve following the displacement cam; In a variable valve mechanism having a variable device that changes according to
The variable device includes a variable arm, a contact that is rotatably supported by a tip bifurcated portion of the variable arm with a support shaft, and contacts the cam surface of the displacement cam ; both sides of the contact on the support shaft and a forked portion of the tip It mounted so as to be positioned in the inside, an actuator for driving a pair of ring diameter smaller than the contact, and a variable cam to change the initial contact position between the contact and the cam surfaces to drive the variable arm, a variable cam And a pair of guide portions straddling the contact, projecting downward, and a downward guide surface formed on the guide portion abuts the ring to guide the contact between the contact surface and the cam surface. A variable valve mechanism characterized by Variable includes arm and the shim interposed between the variable cam, provided a variable cam on the control shaft, the variable valve mechanism according to claim 1, wherein the control shaft coupled to said actuator.

Images