JP2007016766A - Variable valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize quick switching operation in switching in a variable valve gear capable of switching a valve opening characteristic of a valve to fixed control from variable control, alternatively, to the variable control from the fixed control in the variable valve apparatus. <P>SOLUTION: This variable valve gear has an arm joining mechanism 72 as a switching means for switching both-valve variable control and one valve variable control. The one valve variable control is realized in a state of joining a large lift arm 70 and a second rocking cam arm 40R by a pin 76. A pin hole 80 for inserting the pin 76 is formed in the second cam arm 40R pushing/moving a second valve 16R. A position of the pin hole 80 is set so that pin switching operation can be performed when controlled at a working angle aiming at starting the one valve variable control for the purpose of reducing NOx. The cam height of a second driving cam 14 is set so as to get higher than the cam height of a first driving cam 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus, and more particularly to a variable valve operating apparatus for an internal combustion engine that can mechanically change the valve opening characteristics of the valve.

  Conventionally, for example, Patent Document 1 discloses a variable valve operating apparatus for an internal combustion engine that can mechanically change a valve opening characteristic. In this variable valve operating apparatus, two rotary cams are arranged on the cam shaft, and of the two intake valves arranged in the same cylinder, the first intake valve is driven to open and close by the first rotary cam, and the second intake valve is The second rotary cam is opened and closed. A variable valve transmission mechanism composed of a four-bar linkage mechanism is disposed between the first rotary cam and the first intake valve and between the second rotary cam and the second intake valve. .

  The four-bar linkage mechanism of the variable valve device includes an input arm having an input portion that contacts the rotating cam, a transmission arm that is swingably connected to the input arm, a swingable connection to the transmission arm, and a rotation control A swing arm that is swingable about an axis and that transmits a driving force transmitted from a rotary cam to an output unit that opens and closes an intake valve; and a rotational control shaft that rotates about the rotation control shaft, and an input arm It is composed of a control arm that is slidably connected. By controlling the attitude of the four-bar linkage mechanism and changing the relative position between the rotary cam and the input unit, the valve opening characteristics of the intake valve can be mechanically changed.

  Further, the conventional variable valve operating apparatus includes a switching mechanism for switching the valve opening characteristic of the second intake valve from variable control to constant control, or from constant control to variable control. More specifically, a four-bar linkage mechanism (first link mechanism) related to the first intake valve and a four-bar link mechanism (second link mechanism) related to the second intake valve are connected to the variable valve operating device. And a mechanism for holding the posture of the second link mechanism at a posture in which the operating angle of the second intake valve becomes the maximum value or the minimum value when the connection is released. The connection mechanism includes a through hole formed in the control arm of each four-bar linkage mechanism and a connection pin inserted into the through hole. The mechanism for maintaining the posture of the second link mechanism when the connection is released includes a through hole formed in the fixed plate, a through hole formed in a control arm (second control arm) of the second link mechanism, It consists of a connecting pin.

  The connecting pin is always engaged with the through hole of the second control arm, and is also fixed to the control arm (first control arm) side of the first link mechanism while being engaged with the through hole of the second control arm. It can also be moved to the plate side. When the connecting pin moves to the first control arm side and is inserted into the through hole of the first control arm, the second control arm is connected to the first control arm via the connecting pin. By connecting the control arms, the first link mechanism and the second link mechanism always take the same posture. Therefore, in this case, the first valve and the second valve can be controlled to have the same valve opening characteristic.

  On the contrary, the second control arm is connected to the fixed plate via the connecting pin by the connecting pin moving to the fixed plate side and being inserted into the through hole of the fixed plate. By connecting the second control arm and the fixed plate, the posture of the second link mechanism is fixed to a fixed posture. In this case, only the valve opening characteristic of the first valve is controlled in a state where the valve opening characteristic of the second valve is fixed by changing the relative position between the rotary cam and the input unit by controlling the attitude of the first link mechanism. Can be changed mechanically.

  That is, according to the variable valve operating apparatus, when the opening characteristics of the first intake valve and the second intake valve are the same (both valve variable control), the opening characteristics of the first intake valve and the second intake valve are set. Can be selectively executed (one-valve variable control). Thus, by making the valve opening characteristics of the first intake valve and the second intake valve different, in particular, the lift amount of each valve, the intake flow rate is made different to generate a swirl flow (swirl flow) in the combustion chamber. This makes it possible to stabilize combustion in the combustion chamber.

JP 2004-1000055 A

  In the above conventional technique, when switching from the two-valve variable control to the one-valve variable control, the maximum value or the minimum value of the working angle can be obtained once from the current working angle of the second intake valve. There is a description of making it a posture. When switching between the two-valve variable control and the one-valve variable control by such a method, it is necessary to control the maximum value or the minimum value from the operating angle in the current operation region. Further, after the switching, it is necessary to move the first intake valve, which is variably controlled, to a lift amount necessary to obtain an effective intake flow rate difference between these intake valves.

  Thus, when switching from the two-valve variable control to the one-valve variable control, a certain amount of operation time is required. Further, at the time of switching, it is necessary to control the ignition timing and the fuel injection amount so that the torque of the internal combustion engine does not change abruptly. However, in the above conventional technique, no consideration is given to shortening the switching operation time. In this respect, the above-described conventional technology still leaves room for examination.

  The present invention was made to solve the above-described problems, and in a variable valve operating apparatus capable of switching the valve opening characteristics from variable control to constant control, or from constant control to variable control, An object of the present invention is to provide a variable valve operating apparatus that can realize a quick switching operation at the time of switching.

In order to achieve the above object, a first aspect of the present invention provides a variable valve that can change the valve opening characteristic of at least one switching target valve among a plurality of valves from variable control to constant control or from constant control to variable control. A device,
A swinging member interposed between the main cam and the valve to transmit the pressing force of the main cam to the valve;
Valve opening characteristic variable means for variably controlling the valve opening characteristic of the switching target valve by controlling the posture of the swing member within a predetermined range;
A valve-opening characteristic fixing means for controlling the valve-opening characteristic of the switching target valve at a constant rate;
Switching means for switching a valve opening characteristic of the switching target valve from the variable control to the constant control or from the constant control to the variable control;
The switching means is configured to be able to switch the valve opening characteristic of the switching target valve by the posture of the swing member corresponding to the operation region that requires switching of the valve opening characteristic of the switching target valve. It is characterized by.

  Further, according to a second aspect, in the first aspect, the operation region that requires switching of the valve opening characteristics of the switching target valve is a low engine rotation region or a low load region for the purpose of reducing NOx or improving fuel consumption. It is characterized by being.

According to a third aspect of the present invention, in the first or second aspect, the valve opening characteristic variable means includes an intermediate member provided between the main cam and the switching target valve, and a position of the intermediate member. Control means to change,
The intermediate member is shared for a plurality of valves including the switching target valve,
A second cam is provided separately from the main cam,
The valve opening characteristic fixing means includes an input arm that swings in synchronization with the rotation of the second cam,
The switching means is for coupling the rocking member that pushes the switching target valve and the input arm or releasing the coupling.
The profile of the second cam is configured such that the cam height is higher than that of the main cam.

  In a fourth aspect based on the third aspect, the switching means has a predetermined range when there is an operating range that requires switching of the valve opening characteristics of the switching target valve over a predetermined range. The valve opening characteristic of the switching target valve can be switched with the posture of the swinging member that minimizes the operating angle and / or the lift amount of the switching target valve within the range. .

  In a fifth aspect based on the third aspect, the switching means has a predetermined range when there is an operating range that requires switching of the valve opening characteristics of the valve to be switched over a predetermined range. The valve opening characteristic of the switching target valve can be switched by the posture of the swing member so that the operating angle and / or lift amount of the switching target valve is maximized within the range. .

In a sixth aspect based on the first or second aspect, the valve opening characteristic varying means includes an intermediate member provided between the main cam and the switching target valve, and a position of the intermediate member. Control means to change,
The intermediate member is shared for a plurality of valves including the switching target valve,
A second cam is provided separately from the main cam,
The valve opening characteristic fixing means includes an input arm that swings in synchronization with the rotation of the second cam,
The switching means includes a pin, and couples the pin or releases the coupling between the swinging member that pushes the switching target valve and the input arm.
A pin hole into which the pin is inserted is provided in any one of the swing member that pushes the switching target valve and the input arm,
A guide surface for guiding the pin inserted into and withdrawn from the pin hole is formed at an entrance portion of the pin hole.

  In addition, a seventh invention is characterized in that, in the sixth invention, the guide surface has an inclination angle with respect to the axis of the pin hole that becomes smaller as it approaches the entrance of the pin hole.

  Further, in an eighth aspect according to any one of the first to seventh aspects, the profile of the second cam is realized by the main cam in the phase of the switching target valve realized by the second cam. It is characterized by being different from the phase of the valve.

  According to the first aspect of the present invention, the operation time required for the switching operation can be effectively shortened as compared with the case where the switching is performed with the maximum value or the minimum value in the variable range of the valve opening characteristic of the switching target valve. .

  When the operating range that requires switching of the valve opening characteristics of the switching target valve is a low engine speed area or low load area for the purpose of reducing NOx or improving fuel efficiency, the maximum valve opening characteristic variable range of the switching target valve If switching is performed with the value or the minimum value, the time required for the switching operation becomes long. On the other hand, according to the second invention, such an operation time can be effectively shortened.

  When the intermediate member is shared by a plurality of valves including the switching target valve, when the main cam is selected as the drive cam, the valves have the same valve opening characteristics due to the main cam. Driven by. In such a case, when the valve opening characteristic of the switching target valve is to be switched by the posture of the swing member corresponding to the operation region that requires switching of the valve opening characteristic of the switching target valve, If the cam height is the same as the cam height of the main cam, the lift amount of the switching target valve driven by the second cam cannot be controlled to a larger lift amount than other valves driven by the main cam. End up. On the other hand, according to the third invention, the upper limit value of the lift amount of the switching target valve that can be controlled by the second cam is not affected by the presence of the intermediate member, and the swing member corresponding to the desired operation region Thus, it is possible to switch the valve opening characteristics of the switching target valve.

  According to the third aspect, when the switching operation is completed, the lift amount of the switching target valve can be instantaneously changed to a desired large lift amount. In addition, according to the setting of the fourth aspect of the present invention, after the switching operation is completed, the operation time for controlling the other variably controlled valves to a sufficiently small lift amount can be further shortened.

  According to the fifth invention, after the valve opening characteristic of the switching target valve is changed to the constant control, the valves other than the switching target valve operate more than the switching target valve within the predetermined range in the fifth invention. The angle and / or the lift amount are variable in a small region. Thereby, it is possible to prevent a gap from being generated between the second cam and the input arm, and it is possible to prevent a sound and an impact load from being generated between the second cam and the input arm during the lift operation.

  According to the sixth aspect of the invention, even when the pin axis and the pin hole axis do not coincide with each other, when the pin is guided by the guide surface, the swinging member rotates and the pin axis and The axis of the pin hole coincides with the pin hole, and the pin can be coupled. For this reason, according to the present invention, the operation time required for the switching operation can be effectively shortened.

  According to the seventh aspect of the invention, the moving speed of the swinging member when the pin connection is released can be reduced. For this reason, according to the present invention, it is possible to prevent the members from coming into contact with each other at the time of releasing the connection of the pins to generate a sound or an impact load.

  According to the eighth aspect of the present invention, the valve opening phase between the switching target valve driven by the second cam and the other valve driven by the main cam can be used without using a mechanism for changing the valve phase. It can be changed.

Embodiment 1 FIG.
[Configuration of variable valve gear]
FIG. 1 is a view for explaining a mechanism interposed between a drive cam and a valve in the variable valve operating apparatus 1 according to the first embodiment of the present invention. Here, it is assumed that each cylinder of the internal combustion engine is provided with two intake valves and two exhaust valves. The configuration shown in FIG. 1 functions as a device that drives two intake valves or two exhaust valves arranged in a single cylinder.

  As shown in FIG. 1, the camshaft 10 of the variable valve operating apparatus 1 is provided with two drive cams 12 and 14 per cylinder. Two valves 16L and 16R are arranged symmetrically about one drive cam (first drive cam) 12. Between the first drive cam 12 and the valves 16L and 16R, variable valve mechanisms 20L and 20R that link the lift movement of the valves 16L and 16R with the rotational movement of the first drive cam 12 are provided. .

  The other drive cam (second drive cam 14) is arranged so as to sandwich the second valve 16R with the first drive cam 12. A fixed valve mechanism 30 is provided between the second drive cam 14 and the second valve 16R to link the lift movement of the second valve 16R with the rotational movement of the second drive cam 14. The variable valve operating apparatus 1 can selectively switch the interlocking destination of the lift movement of the second valve 16R between the variable valve mechanism 20R and the fixed valve mechanism 30.

(1) Detailed Configuration of Variable Valve Mechanism Next, a detailed configuration of the variable valve mechanisms 20L and 20R will be described first with reference to FIG. FIG. 2 is a view of the variable valve mechanism 20 shown in FIG. 1 as viewed from the axial direction of the cam shaft 10. Since the left and right variable valve mechanisms 20L and 20R are basically symmetrical with respect to the first drive cam 12, the configuration thereof will be described without distinguishing between the left and right variable valve mechanisms 20L and 20R. To do. In the present specification and drawings, when the left and right variable valve mechanisms 20L and 20R are not distinguished, they are simply referred to as the variable valve mechanism 20. Similarly, the components of the variable valve mechanisms 20L and 20R and the symmetrically arranged components such as the valves 16L and 16R are distinguished from each other by L and R that distinguish left and right unless there is a particular need to distinguish them. No symbol shall be attached.

  As shown in FIG. 2, in the variable valve gear 1, the rocker arm 32 is supported by the valve 16. The variable valve mechanism 20 is interposed between the first drive cam 12 and the rocker arm 32 so as to continuously change the interlocking state between the rotational motion of the first drive cam 12 and the rocking motion of the rocker arm 32. It has become.

  As described below, the variable valve mechanism 20 includes a control shaft 34, a control arm 36, a link arm 38, a swing cam arm 40, a first roller 42, and a second roller 44 as main constituent members. . The control shaft 34 is arranged in parallel with the cam shaft 10. The rotation angle of the control shaft 34 can be controlled to an arbitrary angle by an actuator (not shown) such as a motor.

  The control arm 36 is integrally fixed to the control shaft 34 by a bolt 46 (see FIG. 1). The control arm 36 protrudes in the radial direction of the control shaft 34, and an arc-shaped link arm 38 is attached to the protruding portion. The rear end of the link arm 38 is rotatably connected to the control arm 36 by a pin 48. The position of the pin 48 is eccentric from the center of the control shaft 34, and this pin 48 becomes the swing fulcrum of the link arm 38.

  The swing cam arm 40 is swingably supported by the control shaft 34, and the tip thereof is disposed toward the upstream side in the rotation direction of the first drive cam 12. A slide surface 50 that contacts the second roller 44 is formed on the side of the swing cam arm 40 that faces the drive cam 12. The slide surface 50 is formed in a curved surface such that the distance from the first drive cam 12 gradually decreases as the second roller 44 moves from the distal end side of the swing cam arm 40 toward the axial center side of the control shaft 34. ing. A swing cam surface 52 is formed on the opposite side of the slide surface 50. The oscillating cam surface 52 is formed such that the distance from the oscillating center of the oscillating cam arm 40 is constant, and the position away from the non-operating surface 52a is closer to the axis of the control shaft 34. It is comprised with the action surface 52b formed so that distance may become far.

  A first roller 42 and a second roller 44 are disposed between the slide surface 50 of the swing cam arm 40 and the peripheral surface of the first drive cam 12. More specifically, the first roller 42 is disposed so as to contact the circumferential surface of the first drive cam 12, and the second roller 44 is disposed so as to contact the slide surface 50 of the swing cam arm 40. Both the first roller 42 and the second roller 44 are rotatably supported by a connecting shaft 54 fixed to the tip of the link arm 38 described above. Since the link arm 38 can swing about the pin 48 as a fulcrum, the rollers 42 and 44 can also swing along the slide surface 50 and the peripheral surface of the first drive cam 12 while maintaining a certain distance from the pin 48. it can.

  The swing cam arm 40 is provided with a lost motion spring (not shown). The lost motion spring is a compression spring, and the biasing force from the lost motion spring acts as a force that the slide surface 50 biases the second roller 44 and further presses the first roller 42 against the first drive cam 12. . Thus, the first roller 42 and the second roller 44 are positioned in a state where they are sandwiched from both sides by the slide surface 50 and the peripheral surface of the first drive cam 12. The lost motion spring is not limited to the compression spring described above, and may be a torsion spring, for example.

  Below the rocking cam arm 40, the aforementioned rocker arm 32 is arranged. A rocker roller 56 is disposed on the rocker arm 32 so as to face the swing cam surface 52. The rocker roller 56 is rotatably attached to an intermediate portion of the rocker arm 32. One end of the rocker arm 32 is supported by a valve shaft 58 of the valve 16, and the other end of the rocker arm 32 is rotatably supported by a hydraulic lash adjuster 60. During the lift operation, the valve shaft 58 is urged in a closing direction, that is, a direction in which the rocker arm 32 is pushed up by a valve spring (not shown), and the rocker roller 56 is further urged by the hydraulic lash adjuster. 60 is pressed against the swing cam surface 52 of the swing cam arm 40.

  According to the configuration of the variable valve mechanism 20 described above, the pressing force of the first drive cam 12 is transmitted to the slide surface 50 via the first roller 42 and the second roller 44 as the first drive cam 12 rotates. Is done. As a result, when the contact point between the swing cam surface 52 and the rocker roller 56 extends from the non-operation surface 52a to the operation surface 52b, the rocker arm 32 is pushed down and the valve 16 is opened.

  Further, according to the configuration of the variable valve mechanism 20, when the rotation angle of the control shaft 34 is changed, the position of the second roller 44 on the slide surface 50 changes, and the swing cam arm 40 swings during the lift operation. The range changes. More specifically, when the control shaft 34 is rotated counterclockwise in FIG. 2, the position of the second roller 44 on the slide surface 50 moves to the tip side of the swing cam arm 40. Then, the rotation angle of the swing cam arm 40 that is actually required until the rocker arm 32 starts to be pressed after the swing cam arm 40 starts the swing operation by transmitting the pressing force of the first drive cam 12 is: The control shaft 34 becomes larger as it rotates counterclockwise in FIG. That is, according to the variable valve mechanism 20, the operating angle and the lift amount of the valve 16 can be reduced by rotating the control shaft 34 counterclockwise in FIG. By rotating in the opposite direction, the working angle and lift amount of the valve 16 can be increased.

(2) Detailed Configuration of Fixed Valve Mechanism Next, the detailed configuration of the fixed valve mechanism 30 will be described with reference to FIG. 3 in addition to FIG.
As shown in FIG. 1, the fixed valve mechanism 30 is interposed between the second drive cam 14 and the second swing cam arm 40R. The fixed valve mechanism 30 links the swing motion of the second swing cam arm 40R with the rotational motion of the second drive cam 14, and includes a large lift arm 70 driven by the second drive cam 14, a large lift An arm coupling mechanism 72 (see FIG. 3) for coupling the arm 70 to the second swing cam arm 40R is provided.

  The large lift arm 70 is arranged on the control shaft 34 along with the second swing cam arm 40R, and is rotatable independently of the second swing cam arm 40R. An input roller 74 that contacts the peripheral surface of the second drive cam 14 is rotatably supported on the large lift arm 70. A lost motion spring (not shown) is applied to the large lift arm 70, and the spring force acts as a biasing force that presses the input roller 74 against the peripheral surface of the second drive cam 14.

  FIG. 3 is an exploded perspective view of the variable valve mechanism 20 and the fixed valve mechanism 30 shown in FIG. As shown in FIG. 3, the large lift arm 70 is provided with a pin 76 that can be taken in and out toward the second swing cam arm 40R. The large lift arm 70 is formed with a hydraulic chamber 78 having an opening on the second swing cam arm 40 </ b> R side, and the pin 76 is fitted into the hydraulic chamber 78. Hydraulic oil is supplied to the hydraulic chamber 78 via a hydraulic passage (not shown). When the hydraulic pressure in the hydraulic chamber 78 is increased by such a configuration, the pin 76 is pushed out from the hydraulic chamber 78 toward the second swing cam arm 40R by the hydraulic pressure.

  On the other hand, a pin hole 80 having an opening on the large lift arm 70 side is formed in the second swing cam arm 40R. The pin 76 and the pin hole 80 are arranged on the same arc centered on the control shaft 34. Accordingly, when the second swing cam arm 40R is positioned at a predetermined rotation angle with respect to the large lift arm 70, the position of the pin hole 80 and the position of the pin 76 are made to coincide. A return spring 82 and a piston 84 are arranged in the pin hole 80 from the back side.

  According to the above configuration, the pin 76 contacts the piston 84 when the position of the pin hole 80 and the position of the pin 76 coincide. At this time, if the force in which the hydraulic pressure in the hydraulic chamber 78 pushes the pin 76 is greater than the force by which the return spring 82 pushes the piston 84, the pin 76 pushes the piston 84 into the back of the pin hole 80. Enter the pin hole 80. By inserting the pin 76 into the pin hole 80, the swing cam arm 40 </ b> R and the large lift arm 70 are coupled via the pin 76. That is, the arm coupling mechanism 72 is configured by the pin 76, the hydraulic chamber 78 to which hydraulic oil is supplied, the pin hole 80, the return spring 82, and the piston 84.

  In the variable valve operating apparatus 1, the pin 76 and the pin hole 80 are configured so that their positions coincide with each other when the swing cam arm 40 </ b> R is positioned at a predetermined rotation angle with respect to the large lift arm 70. When the positions of the pin 76 and the pin hole 80 overlap, the pin 76 is inserted into the pin hole 80, and the large lift arm 70 is coupled to the second swing cam arm 40R. In the variable valve operating apparatus 1, the large lift arm 70 is coupled to the second swing cam arm 40R by the arm coupling mechanism 72, whereby the interlocking destination of the lift movement of the second valve 16R is fixed from the variable valve mechanism 20R to the fixed valve actuation. Switching to the mechanism 30 is possible. Conversely, by releasing the coupling between the large lift arm 70 and the second swing cam arm 40R by the arm coupling mechanism 72, the interlocking destination of the lift movement of the second valve 16R is changed from the fixed valve mechanism 30 to the variable valve mechanism 20R. Can be switched.

  When the large lift arm 70 and the second swing cam arm 40R are not coupled, the rotational movement of the camshaft 10 moves from the first drive cam 12 via the first roller 42 and the second roller 44 to the first swing cam 40R. It is transmitted to the slide surfaces 50 of the cam arm 40L and the second swing cam arm 40R. Therefore, in this case, the operating angle and the lift amount of the first valve 16L and the second valve 16R can be controlled in conjunction with the rotation of the control shaft 34 (both valve variable control).

  On the other hand, when the large lift arm 70 and the second swing cam arm 40R are coupled, the rotational motion of the cam shaft 10 is transferred from the second drive cam 14 via the large lift arm 70 to the second swing cam arm 40R. Communicated. The large lift arm 70 and the second swing cam arm 40R are coupled in a state where the control shaft 34 is rotated and the position of the second roller 44R on the slide surface 50R is moved to a position described later with reference to FIG. Is done. Therefore, the valve opening characteristic of the second valve 16R in this case is mechanically determined by the shape and positional relationship of the second drive cam 14, the large lift arm 70, and the second swing cam arm 40R, and the rotation angle of the control shaft 34 Regardless of whether the valve opening characteristic is always fixed. On the other hand, the rotational motion of the cam shaft 10 is transmitted from the first drive cam 12 to the first swing cam arm 40L via the first roller 42 and the second roller 44L. Therefore, the valve opening characteristic of the first valve 16L in this case changes in conjunction with the rotation angle of the control shaft 34, as in the case where the large lift arm 70 and the swing cam arm 40R are not coupled.

  As described above, according to the variable valve operating apparatus 1, the valve opening characteristic of only the first valve 16L can be variably controlled in a state where the large lift arm 70 and the second swing cam arm 40R are coupled. Becomes possible (single-valve variable control). The variable valve operating apparatus 1 is a valve operating apparatus capable of continuously changing both the lift amount and the operating angle of the valve 16 as described above. Hereinafter, unless otherwise specified, in the present specification, a portion to be described as “lift amount and working angle” of the valve 16 is simply abbreviated as “working angle” or “lift amount” of the valve 16. There are things to do.

(3) Setting of pin hole position and cam profile in the present embodiment FIG. 4 is a diagram for explaining the setting of the pin hole 80 position in the variable valve apparatus 1 shown in FIG. More specifically, FIG. 4 (A) shows the setting of the pin hole position in the variable valve operating apparatus A referred to for comparison with the variable valve operating apparatus 1 of the present embodiment, and FIG. 4 (B) shows the present embodiment. The setting of the pin hole 80 position in the variable valve operating apparatus 1 is shown respectively. The variable valve device A referred to for comparison is configured in the same manner as the variable valve device 1 of the present embodiment except for the setting of the pin hole position and the setting of the cam height of the second drive cam. It shall be. Here, the contact point between the rocker roller 56 and the second rocking cam arm 40R is referred to as “roller contact point X”, and the boundary point between the non-working surface 52a and the working surface 52b of the second rocking cam arm R is defined. , Referred to as “lift start point Y”. The angle formed by the straight line connecting the rotation center P of the second swing cam arm 40R and the rotation center Q of the rocker roller 56 and the straight line connecting the rotation center P and the lift start point Y is referred to as “arm angle θ”. Called.

  From the viewpoint of productivity of the cam shaft 10 provided with the first drive cam 12 and the second drive cam 14, the cam profiles of the first drive cam 12 and the second drive cam 14 are configured to be the same. Is desirable. In the variable valve operating apparatus A shown in FIG. 4A, the first drive cam and the second drive cam are configured as such. In the variable valve apparatus A, the second roller on the second swing cam arm side always applies the pressing force of the first drive cam to the second swing cam arm regardless of whether the two-valve variable control or the one-side variable control is in effect. It is trying to be transmitted to the slide surface. Therefore, when the cam heights of the first drive cam and the second drive cam are the same, the lift amount obtained by the fixed valve mechanism is the maximum lift amount that can be varied by the variable valve mechanism. If the pin hole position is set in a smaller state, the valve driven by the fixed valve mechanism will be further driven by the variable valve mechanism after reaching the maximum lift amount. As a result, the one-valve variable control is not established.

  Therefore, in the single valve variable control, in order to independently control the working angle of the second valve on the fixed side while ensuring the maximum variable range of the working angle by the variable valve mechanism, the pin hole is set. The position needs to be a position where the posture of the second rocking cam arm is the maximum value of the variable range of the operating angle by the variable valve mechanism or the operating angle beyond it. The variable valve operating apparatus A shown in FIG. 4A shows the setting of the pin hole position in which such consideration is made.

  More specifically, FIG. 4A shows a state in which the pressing force of the drive cam is not acting on the second swing cam arm. FIG. 4A shows a state in which the posture of the second swing cam arm is controlled by the control shaft so as to obtain a posture in which the maximum operating angle is obtained. In the variable valve gear A, the position of the pin hole on the second swing cam arm is set so that the position of the pin and the pin hole coincides when the posture of the second swing cam arm is in such a state. Has been. The arm angle θ in this state is θ1. If the pin hole position is set in such a manner, a more effective swirl flow can be formed by sufficiently increasing the difference between the lift amounts of the two valves.

  On the other hand, in the variable valve operating apparatus 1 of the present embodiment, the position of the pin hole 80 is determined for the purpose of giving consideration as described below. That is, in an internal combustion engine, for example, in a low load operation region or a low engine speed region where the operating angle of the valve 16 is about 100 to 200 ° CA, it is effective in the combustion chamber for the purpose of reducing NOx emissions. In order to generate a smooth swirl flow, there may be a request to perform one-valve variable control. Further, in an internal combustion engine, for example, there is a case where a single valve variable control is desired to be performed in the low load operation region or the low engine speed region for the purpose of improving fuel consumption. In response to such a request, in the internal combustion engine, the region where the variable valve control is switched from the variable valve control to the single valve variable control is a predetermined low engine speed region or a low load region for the purpose of reducing NOx or using the fuel efficiency effect as an index. Is set to be

  In the variable valve operating apparatus 1, as shown in FIG. 4B, the arm angle θ is at an angle θ2 larger than the angle θ1, in other words, the valve 16 of the variable valve mechanism 10 is included. In a state where the posture of the second swing cam arm 40R is controlled by the control shaft 34 so as to be an intermediate working angle in the variable range, the second swing is made so that the positions of the pin 76 and the pin hole 80 coincide with each other. The position of the pin hole 80 on the cam arm 40R is set. In other words, the second swing is set to a posture in which a working angle corresponding to the operation region in which the switching operation from the double valve variable control to the single valve variable control (hereinafter sometimes simply referred to as “pin switching operation”) is required is obtained. The position of the pin hole 80 is set so that such a pin switching operation can be executed when the moving cam arm 40R is present.

  More specifically, in this embodiment, when the operating angle is controlled to about 100 to 200 ° CA, that is, it is controlled to the operating angle at which the one-valve variable control is to be started for the purpose of NOx reduction or the like. Sometimes, the position of the pin hole 80 is set so that the pin switching operation can be executed. Furthermore, in the range where the pin switching operation is necessary (for example, the range where the working angle is about 100 to 200 ° CA in this case), the working angle is 100 ° CA at the smallest working angle side. The position of the pin hole 80 is determined so that a pin switching operation can be performed (when the second swing cam arm 40R is in a posture of the same).

  In the variable valve operating apparatus 1, as shown in FIG. 4B, the drive cams 12, such that the cam height of the second drive cam 14 is higher than the cam height of the first drive cam 12. Fourteen profiles are set. Specifically, the cam height of the second drive cam 14 is such that the operating angle of the second valve 16R is equal to or greater than the maximum value of the operating angle of the first valve 16L driven by the variable valve mechanism 10 when the pin is coupled. It is configured to be a value.

  The pin switching operation described above is performed according to the following procedure. That is, first, the control shaft 34 is driven and moved from a working angle posture of the second swing cam arm 40R in the current operating state of the internal combustion engine to a working angle posture in which the position of the pin hole 80 and the position of the pin 76 overlap. Operating time T1 is required. When the pin switching operation is completed and the second swing cam arm 40R and the large lift arm 70 are coupled, the lift movement of the second valve 16R is immediately switched to the operation by the fixed valve mechanism 30. However, for the first valve 16L driven by the variable valve mechanism 10, after the pin switching operation is completed, the first swing cam arm 40L is moved to a small working angle posture for realizing the target swirl flow. An operation time T2 for movement is required.

  According to the configuration of the variable valve operating apparatus 1, as described above, the pin switching operation is performed when the second swing cam arm 40 </ b> R is in the working angle posture that requires the pin switching operation. For this reason, the operating time T1 can be shortened compared with the variable valve operating apparatus A (FIG. 4A) in which the pin hole position is set to the maximum value of the variable operating angle range by the variable valve operating mechanism 10. it can. The variable valve apparatus 1 is configured such that the cam height of the second drive cam 14 is higher than the cam height of the first drive cam 12. Therefore, the operating angle of the second valve 16R that is driven so as to have a constant value during the one-valve variable control can be set to be equal to or larger than the maximum lift amount that the variable valve mechanism 10 can produce. It becomes possible. In addition, in the present embodiment, since the characteristics of the second valve 16R are realized by a method in which the heights of the two drive cams 12 and 14 are made different, the second switching cam is completed when the pin switching operation is completed. The valve 16R can be instantaneously changed to a target large operating angle.

  As described above, after the pin coupling, the operation angle posture of the first swing cam arm 40L is moved from the operation angle posture that has been subjected to the pin coupling operation to the small operation angle posture that can realize the target swirl. Time T2 is required. According to the variable valve operating apparatus 1, compared to the variable valve operating apparatus A (FIG. 4A) in which the pin hole position is set to the maximum value of the operating angle variable range by the variable valve operating mechanism 10. Such an operation time T2 can be shortened.

  Further, in order to generate a sufficient swirl flow, it is effective to increase the difference in lift amount between the two valves 14R and 14L. Therefore, such a targeted swirl flow is realized after pin coupling. Therefore, the operating angle posture of the first swing cam arm 40L controlled for this is a sufficiently small operating angle posture. In the variable valve operating apparatus 1, as described above, the position of the pin hole 80 is determined so that the pin switching operation can be performed on the minimum working angle side in the range where the pin switching operation is necessary. For this reason, the working angle posture of the first rocking cam arm 40L can be quickly changed to a target sufficient working angle posture. That is, it is possible to more effectively shorten the operation time T2 described above.

In the first embodiment described above, the valve 16L is the “switching target valve” in the first invention, the swing cam arm 40 is the “swing member” in the first invention, the control shaft 34, the control The arm 36, the link arm 38, the first roller 42, the second roller 44, and the slide surface 50 are the “valve opening characteristic varying means” in the first invention, and the large lift arm 70 is the “opening” in the first invention. The arm coupling mechanism 72 corresponds to the “switching means” in the first aspect of the invention.
In the first embodiment described above, the first roller 42 and the second roller 44 are the “intermediate member” in the third invention, and the control shaft 34, the control arm 36, and the link arm 38 are the third member. The second drive cam 14 corresponds to the “second cam” in the third invention, and the large lift arm 70 corresponds to the “input arm” in the third invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a diagram for explaining the configuration of the variable valve operating apparatus 90 according to the second embodiment. The variable valve operating apparatus 90 of the present embodiment is the same as the variable valve operating apparatus 1 of the first embodiment described above except that the configuration of the cam shaft 92 is different. That is, also in the variable valve operating apparatus 90, the second swing cam arm 40R has a posture that provides an operating angle corresponding to the operation region in which the switching operation (pin switching operation) from the two-valve variable control to the one-valve variable control is required. The position of the pin hole 80 is set so that the pin switching operation can be executed when there is a pin.

  Further, as shown in FIG. 5, in the variable valve apparatus 90, the cam height of the second drive cam 96 is higher than the cam height of the first drive cam 94, as in the first embodiment. It is configured. Furthermore, the first drive cam 94 and the second drive cam 96 are configured to have different attachment angles with respect to the cam shaft 92. Specifically, the second drive cam 96 is fixed to a position shifted from the first drive cam 94 by a predetermined angle α on the advance side.

  FIG. 6 is a diagram showing the valve opening characteristics of the valve 16 realized by the variable valve operating apparatus 90 shown in FIG. According to the configuration of the variable valve operating apparatus 90 described above, the one-valve variable control is driven by the second drive cam 96 so as to have a constant valve opening characteristic via the large lift arm 70 and the second swing cam arm 40R. The opening timing of the second valve 16R can be advanced compared to the opening timing of the first valve 16L that is variably controlled. According to the setting of the cam shaft 92, the first valve 16L, which is controlled to have a small operating angle, is opened after the second valve 16R is first opened to cause negative pressure in the cylinder. it can. Thereby, the flow velocity of the intake air when the first valve 16L on the small operating angle side is opened can be increased, and an effective swirl flow can be generated. Moreover, such an effect can be realized without using a mechanism (VVT mechanism) for changing the phase of the valve 16.

  By the way, in the second embodiment described above, the second drive cam 96 is fixed at a position shifted from the first drive cam 94 by a predetermined angle α on the advance side. The method for making the phases of the two cams different is not limited to this. FIG. 7 is a diagram for explaining the configuration of such a modification. In the variable valve operating apparatus 100 shown in FIG. 7, unlike the variable valve operating apparatus 90 shown in FIG. 5, the first drive cam 102 is shifted to the advance side by a predetermined angle β with respect to the second drive cam 104. Fixed in position.

  FIG. 8 is a diagram showing the valve opening characteristics of the valve 16 realized by the variable valve apparatus 100 shown in FIG. According to the configuration of the variable valve operating apparatus 100 described above, the opening timing of the first valve 16L variably controlled by the variable valve mechanism 10 during the one-valve variable control is the second valve driven by the fixed valve mechanism 30. It can be advanced compared to the valve opening timing of the valve 16R. According to such setting of the camshaft 106, it is possible to effectively reduce the pumping loss by first opening the first valve 16L before the inside of the cylinder becomes negative pressure. Moreover, such an effect can be realized without using a mechanism (VVT mechanism) for changing the phase of the valve 16.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS.
The variable valve operating apparatus 110 of the present embodiment differs in the posture of the second swing cam arm 40R when performing a switching operation (pin switching operation) from the both-valve variable control to the one-valve variable control, Except for the point that the height of the second drive cam 114 with respect to the first drive cam 112 is different, the configuration is the same as the variable valve operating apparatus 1 of the first embodiment described above.

  FIG. 9 is a torque curve diagram for explaining an operation region in which the single valve variable control is executed in the variable valve operating apparatus 110 of the present embodiment. As shown in FIG. 9, in the high-load high-rotation region, the double-valve variable control is performed in which both valves have a large working angle. In the other regions, the single-valve variable control in which only the valve 16L is varied to a small working angle. Executed. In the first embodiment described above, the pin switching operation is performed on the smallest working angle side in the region where such single valve variable control is performed. On the other hand, the variable valve operating apparatus 110 of the present embodiment is characterized in that the pin switching operation is performed on the largest operating angle side in the region where such single valve variable control is performed.

  FIG. 10 is a diagram for explaining a problem when the pin switching operation is performed on the small operating angle side in the region where the one-valve variable control is performed. FIG. 10A shows a state where the second roller 44 in contact with the swing cam arm 40 is positioned on the distal end side of the swing cam arm 40, that is, a small operating angle control state. FIG. 10B shows a state where the one-valve variable control state is achieved by performing a pin switching operation in the state shown in FIG. 10A, and then the control shaft 34 is rotated to move the second roller 44 of the control shaft 34. The state moved to the shaft center side, that is, the large operating angle control state is shown. In the state shown in FIG. 10B, a gap is generated between the second driving cam 14 on the fixed working angle side and the input roller 74. This is because, in the state shown in FIG. 10A, the second swing cam arm 40R is moved by the second roller 44 after the second swing cam arm 40R and the large lift arm 70 are connected by the pin 76. This is because the posture has changed and the posture of the large lift arm 70 has changed accordingly. If such a gap is generated between the second drive cam 14 and the input roller 74, the second drive cam 14 and the input roller 74 are repeatedly contacted every time during the lift operation, and sound and impact load are generated at the time of contact. It will occur.

  FIG. 11 is a diagram for explaining the operation when the pin switching operation is set in the present embodiment. FIG. 11A shows a state where the second roller 44 is located at a position where the largest working angle is obtained in the region where the one-valve variable control is performed. In the present embodiment, as described above, the pin hole 116 is provided on the second swing cam arm 40R so that the pin switching operation can be executed in this state. In FIG. 11B, in the state shown in FIG. 11A, after the pin switching operation is performed to change to the one-valve variable control state, the control shaft 34 is rotated to move the second roller 44 to the swing cam arm 40. The state moved to the tip side of the valve, that is, the small operating angle control state is shown. In the state shown in FIG. 11B, the first swing cam arm 40L on the variable working angle side is maintained in contact with the second roller 44, but the second rocking side on the fixed working angle side. A gap is generated between the swing cam arm 40 </ b> R and the second roller 44 when the second roller 44 moves away from the control shaft 34.

  As described above, according to the setting of the present embodiment, the one-valve variable control is executed on the side of the operating angle that is always smaller than the operating angle at which the pin switching operation is executed. For this reason, a gap is generated between the second swing cam arm 40R and the second roller 44 during the one-valve variable control. However, as shown in FIG. Since there is no gap between them, no sound or impact load is generated during the lift operation.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 12 is a diagram for explaining the configuration of the variable valve apparatus 120 according to the fourth embodiment of the present invention. As shown in FIG. 12, the variable valve apparatus 120 of the present embodiment is configured in the same manner as the variable valve apparatus 1 of the first embodiment described above, except for the following points. That is, the difference between them is that the first drive cam 12 for pushing the first roller 42 and the second drive cam 122 for pushing the input roller 74 have the same profile. The point is that the configuration of the arm coupling mechanism 124 is different.

  More specifically, in the arm coupling mechanism 124 of the present embodiment, when the posture of the second swing cam arm 126R is such that the maximum operating angle is obtained, the axis of the pin 76 and the axis of the pin hole 128 are Are configured to match. The state shown in FIG. 12 is a state in which the posture of the second rocking cam arm 126R is such that a working angle smaller than the maximum working angle by a predetermined value can be obtained with respect to the pin hole 128 thus configured. That is, a state is shown in which the axis of the pin 76 and the axis of the pin hole 128 are inconsistent. The arm coupling mechanism 124 of the present embodiment is characterized in that a pin switching operation can be performed in the state shown in FIG.

  FIG. 13 is a cross-sectional view for explaining a characteristic configuration of the arm coupling mechanism 124 of the present embodiment. In the configuration shown in FIG. 3 described above, the hydraulic chamber 78 is provided on the large lift arm 70 side, but here the oil passage 132 and the hydraulic chamber are not on the large lift arm 130 side but on the second swing cam arm 126R side. 134 is provided. A pin hole 128 for accommodating the piston 136 and the return spring 138 is formed on the large lift arm 130 side. The arm coupling mechanism 124 of this embodiment is characterized by the shape of the portion indicated by the reference numeral “A” in the pin hole 128 of the large lift arm 130.

  FIG. 14 is an enlarged view of a part A in FIG. More specifically, FIG. 14A shows a view of the pin hole 128 viewed from the hydraulic chamber 134 side, and FIG. 14B shows a cross section of the portion A. As shown in FIG. 14, a guide surface 128 a for guiding the pin 76 is formed in the entrance portion of the pin hole 128. The guide surface 128a is a portion on the direction side (the right side in FIG. 14B) in which the second swing cam arm 126R moves during the pin switching operation so that the pin 76 can be easily inserted into the pin hole 128. In FIG. 3, the shape is formed so as to have a larger recessed R shape. The guide surface 128a is formed in an R shape having a gradually increasing radius as it approaches the inlet side of the pin hole 128. In other words, the guide surface 128a is inclined with respect to the axis of the pin hole 128 as it approaches the inlet side of the pin hole 128. It is formed so that the angle gradually decreases. The above-described configuration of the arm coupling mechanism 124 includes the guide surface 128a on the second swing cam arm 40R side even in the configuration in which the hydraulic chamber 78 is provided on the large lift arm 70 side (configuration shown in FIG. 3). It can be similarly realized by providing a similar guide surface.

  FIG. 15 is a diagram for explaining the operation at the time of pin switching in the present embodiment. The state shown in FIG. 15A shows a state where the axis of the pin 76 and the axis of the pin hole 128 do not match. According to the arm coupling mechanism 124 of the present embodiment, even when the axis of the pin 76 and the axis of the pin hole 128 do not coincide with each other, the pin 76 that has been supplied with hydraulic pressure guides to the guide surface 128a. As a result, as shown in FIG. 15B, the second swing cam arm 126R rotates, and the axis of the pin 76 and the axis of the pin hole 128 coincide with each other. As a result, the pin 76 can be inserted into the pin hole 128.

  FIG. 16 is a diagram for explaining the operation of the second swing cam arm 126R at the time of pin switching. FIG. 12 described above corresponds to the state in FIG. According to the arm coupling mechanism 124 of the present embodiment described above, the pin switching operation can be performed even when the axis of the pin 76 and the axis of the pin hole 128 do not match as shown in FIG. FIG. 16 shows a state where the pin switching operation is completed by rotating the second swing cam arm 126R as shown in FIG. 15B after the pin switching operation is executed in the state shown in FIG. . That is, according to such a pin switching operation, the pin 76 is inserted into the pin hole 128 of the second rocking cam arm 126R that had the same posture as the first rocking cam arm 40L before the start of the pin switching operation. With this, it rotates to the position shown in FIG.

  As described above, according to the configuration of the present embodiment, when the pin switching operation is executed, the control shaft 34 is driven to the working angle posture where the axis of the pin 76 and the axis of the pin hole 128 coincide with each other. 2 There is no need to move the swing cam arm 126R. That is, it is possible to reduce the operation time when the second swing cam arm 126R is moved to the working angle posture capable of performing the pin switching operation when a request for the single valve variable control occurs. Further, according to the above configuration, since the pin 76 is connected at a position where the second swing cam arm 126R itself rotates to obtain the maximum operating angle, the second drive cam as in the first and second embodiments described above. The cam height of 122 need not be higher than that of the first drive cam 12. However, in the configuration of the present embodiment, of course, the cam height of the second drive cam 122 may be different from the cam height of the first drive cam 12.

  In the configuration of the arm coupling mechanism 124 described above, the guide surface 128a is formed in an R shape having a gradually increasing radius as it approaches the inlet side of the pin hole 128. For this reason, when switching from the single valve variable control to the double valve variable control, that is, when the pin 76 comes out of the pin hole 128, as shown in FIG. The speed of the swing cam arm 126R can be gradually reduced by the effect of the shape of the guide surface 128a. As a result, when the connection of the pin 76 is released, when the second swing cam arm 126R and the second roller 44 come into contact again, the contact can be made gently, and the sound and impact load at the time of contact can be made. Can be reduced.

  By the way, in Embodiment 4 mentioned above, although the guide surface 128a of the pin hole 128 is formed in R shape, the guide surface of this invention is not limited to this, For example, at the entrance of a pin hole You may have the shape chamfered in multiple steps so that the inclination | tilt angle with respect to the axis line of a pin hole may become so small that it approaches.

  In the above-described fourth embodiment, the guide surface 128a corresponds to the “guide surface” in the sixth invention.

In the variable valve apparatus of Embodiment 1 of this invention, it is a figure for demonstrating the mechanism interposed between a drive cam and a valve | bulb. It is the figure which looked at the variable valve mechanism shown in FIG. 1 from the axial direction of the cam shaft. It is a disassembled perspective view of the variable valve mechanism and fixed valve mechanism shown in FIG. It is a figure for demonstrating the setting of the pin hole position in the variable valve apparatus shown in FIG. It is a figure for demonstrating the structure of the variable valve apparatus in Embodiment 2 of this invention. It is a figure which shows the valve opening characteristic of the valve | bulb implement | achieved by the variable valve apparatus shown in FIG. It is a figure for demonstrating the structure of the modification of the variable valve apparatus in Embodiment 2 of this invention. It is a figure which shows the valve opening characteristic of the valve | bulb implement | achieved by the variable valve apparatus shown in FIG. In the variable valve apparatus of Embodiment 3 of this invention, it is a torque curve figure for demonstrating the driving | operation area | region where single valve variable control is performed. It is a figure for demonstrating the problem at the time of performing pin switching operation | movement at the small working angle side of the area | region which performs one-valve variable control. It is a figure for demonstrating operation | movement when the setting of the pin switching operation | movement in Embodiment 3 of this invention is made | formed. It is a figure for demonstrating the structure of the variable valve apparatus of Embodiment 4 of this invention. It is sectional drawing for demonstrating the characteristic structure of the arm coupling mechanism of Embodiment 4 of this invention. It is a figure which expands and shows the site | part A in FIG. It is a figure for demonstrating the operation | movement at the time of the pin switching in Embodiment 4 of this invention. It is a figure for demonstrating operation | movement of the 2nd rocking cam arm at the time of pin switching. It is a figure which expands and shows the site | part A in FIG.

Explanation of symbols

1, 90, 100, 110, 120 Variable valve gear 10, 92, 106 Cam shaft 12, 94, 102, 112 First drive cam 14, 96, 104, 114, 122 Second drive cam 16 Valve 20 Variable valve Mechanism 30 Fixed valve mechanism 34 Control shaft 40L First swing cam arm 40R, 126R Second swing cam arm 70, 130 Large lift arm 72, 124 Arm coupling mechanism 76 Pin 78, 134 Hydraulic chamber 80, 116, 128 Pin hole 128a Guide surface

Claims (8)

A variable valve operating device capable of changing a valve opening characteristic of at least one switching target valve among a plurality of valves from variable control to constant control or from constant control to variable control,
A swinging member interposed between the main cam and the valve to transmit the pressing force of the main cam to the valve;
Valve opening characteristic variable means for variably controlling the valve opening characteristic of the switching target valve by controlling the posture of the swing member within a predetermined range;
A valve-opening characteristic fixing means for controlling the valve-opening characteristic of the switching target valve at a constant rate;
Switching means for switching a valve opening characteristic of the switching target valve from the variable control to the constant control or from the constant control to the variable control;
The switching means is configured to be able to switch the valve opening characteristic of the switching target valve by the posture of the swing member corresponding to the operation region that requires switching of the valve opening characteristic of the switching target valve. A variable valve gear characterized by the above.   2. The variable valve operating system according to claim 1, wherein the operation region that requires switching of the valve opening characteristic of the switching target valve is a low engine rotation region or a low load region for the purpose of reducing NOx or improving fuel consumption. apparatus. The valve opening characteristic varying means includes an intermediate member provided between the main cam and the switching target valve, and a control means for changing the position of the intermediate member,
The intermediate member is shared for a plurality of valves including the switching target valve,
A second cam is provided separately from the main cam,
The valve opening characteristic fixing means includes an input arm that swings in synchronization with the rotation of the second cam,
The switching means is for coupling the rocking member that pushes the switching target valve and the input arm or releasing the coupling.
3. The variable valve operating apparatus according to claim 1, wherein the profile of the second cam is configured to have a cam height higher than that of the main cam. 4.   The switching means has an operating angle and / or lift amount of the switching target valve within the predetermined range when there is an operating range that requires switching of the valve opening characteristics of the switching target valve over a predetermined range. 4. The variable valve operating apparatus according to claim 3, wherein the valve-opening characteristic of the switching target valve can be switched with the posture of the swinging member so that the minimum value is minimized.   The switching means has an operating angle and / or lift amount of the switching target valve within the predetermined range when there is an operating range that requires switching of the valve opening characteristics of the switching target valve over a predetermined range. 4. The variable valve operating apparatus according to claim 3, wherein the valve-opening characteristic of the switching target valve can be switched with the posture of the swinging member so that the maximum value is obtained. The valve opening characteristic varying means includes an intermediate member provided between the main cam and the switching target valve, and a control means for changing the position of the intermediate member,
The intermediate member is shared for a plurality of valves including the switching target valve,
A second cam is provided separately from the main cam,
The valve opening characteristic fixing means includes an input arm that swings in synchronization with the rotation of the second cam,
The switching means includes a pin, and couples the pin or releases the coupling between the swinging member that pushes the switching target valve and the input arm.
A pin hole into which the pin is inserted is provided in any one of the swing member that pushes the switching target valve and the input arm,
The variable valve operating apparatus according to claim 1 or 2, wherein a guide surface for guiding the pin inserted into and withdrawn from the pin hole is formed at an inlet portion of the pin hole.   7. The variable valve operating apparatus according to claim 6, wherein the guide surface has a smaller inclination angle with respect to the axis of the pin hole as it approaches the inlet of the pin hole. The profile of the second cam is configured such that the phase of the switching target valve realized by the second cam is different from the phase of the valve realized by the main cam. 8. The variable valve operating apparatus according to any one of 7 above.

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