JP2008095620A - Variable valve gear for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve gear for an internal combustion engine capable of avoiding variation in deviation of valve characteristics of an engine valve from a correct state among cylinders when a control shaft is thermally expanded in the axial direction. <P>SOLUTION: A collar 55 is interposed between an input arm 17 and an output arm 18 in a valve lift variable mechanism 14 of the respective cylinders, and the collar 55 is relatively movable in the axial direction of the control shaft 16 with respect to a vertical wall part 45. When the control shaft 16 is thermally expanded in the axial direction and a slider is displaced in the axial direction, the input arm 17 and the output arm 18 engaged with the slider are also displaced in the axial direction. Therefore, a relative position of the slider and the input arm 17 and the output arm 18 in the cylinders in the axial direction is not varied during thermal expansion, and deviation of the valve characteristics of an intake valve from the correct state caused by variation of the relative position can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  2. Description of the Related Art An internal combustion engine such as an automobile engine is known that includes a variable valve lift mechanism that varies the valve characteristics of an engine valve such as an intake valve and an exhaust valve. For example, in the internal combustion engine of Patent Document 1, a variable valve lift mechanism provided for each cylinder of the internal combustion engine is provided between a plurality of standing wall portions and separated from the adjacent variable valve lift mechanism by the standing wall portion. . The variable valve lift mechanism is engaged with a control shaft extending over each cylinder and penetrating through each standing wall and displaced in the axial direction based on the drive of the shaft, and is engaged with the slider. And a variable drive unit that is driven to vary the valve characteristic of the engine valve based on the displacement of the slider in the axial direction.

An actuator for driving the shaft is connected to the end of the control shaft. The actuator is driven by the control shaft to displace the slider relative to the variable drive unit in the axial direction of the shaft, so that the variable drive unit is driven and the valve characteristics of the engine valves of the cylinders are simultaneously adjusted. Be changed. When the slider is displaced in the axial direction of the control shaft, the displacement of the variable drive unit corresponding to the slider in the axial direction is restricted by the standing wall portion. Accordingly, it is possible to prevent the variable drive unit from being displaced in the same direction as the slider along with the displacement of the slider, and the relative movement of the control shaft in the axial direction with respect to the variable drive unit of the slider cannot be prevented.
JP 2001-263015 A (FIGS. 4 and 21)

  By the way, since the end portion of the control shaft is connected to the actuator, it extends in the axial direction with reference to the end portion when the shaft is thermally expanded in the axial direction. Thus, when the control shaft extends in the axial direction due to thermal expansion, the engagement position of the slider with respect to the shaft shifts from the appropriate position in the axial direction by the thermal expansion, and accordingly, the slider also shifts in the axial direction.

  When the control shaft is thermally expanded, the standing wall portion that restricts the displacement of the variable drive unit in the axial direction is also thermally expanded, and thereby the variable drive unit is also displaced in the axial direction. Here, if the displacement in the axial direction of the variable drive portion due to the thermal expansion of the standing wall portion is equal to the displacement in the axial direction of the slider due to the thermal expansion of the control shaft, the slider in the axial direction relative to the variable drive portion There is no change in the relative position, and the valve characteristic does not change from the proper state.

  However, the standing wall is made of an aluminum alloy or the like with an emphasis on weight reduction of the internal combustion engine, and the control shaft is made of a different material from the standing wall and the control shaft. The coefficient of thermal expansion of both is not the same. Further, while the standing wall portion is fixed to the cylinder head, the control shaft has only its end connected to the actuator. As described above, since the thermal expansion coefficient and the installation mode of the two are different, it is unlikely that the variable drive unit and the slider are displaced by the same amount in the axial direction when the standing wall portion and the control shaft are thermally expanded. More specifically, the displacement of the variable drive unit in the axial direction due to the thermal expansion of the standing wall portion is slight, whereas the displacement of the slider in the axial direction due to the thermal expansion of the control shaft may be large. high.

  Accordingly, during thermal expansion of the control shaft, when the slider engaged with the shaft is displaced from the appropriate position in the axial direction, the relative position of the slider and the variable drive unit in the axial direction changes, and accordingly, the valve The characteristic will deviate from the proper state. However, if the deviation from the appropriate state of the valve characteristics is uniform in each cylinder, the valve characteristics can be made appropriate in all cylinders by driving the control shaft in consideration of the deviation. Conceivable.

  However, the amount of thermal expansion in the axial direction with the end portion of the control shaft as a reference is larger as the portion is farther from the end portion. This is because as the distance from the end of the control shaft increases, the amount of the control shaft between the ends increases.

  In this way, the portion of the control shaft that is farther from the end portion has a larger amount of thermal expansion in the axial direction with respect to the end portion, so that the cylinder that is located farther from the end portion is more controlled. The deviation in the axial direction from the appropriate value of the slider engagement position with respect to the shaft becomes large. As a result, as the cylinder is far from the end, the displacement in the axial direction from the appropriate position of the slider increases, and the change in the relative position in the axial direction relative to the variable drive portion of the slider also increases. The deviation of the valve characteristics of the engine valve from the proper state becomes large. Therefore, when thermal expansion in the axial direction occurs in the control shaft, the deviation of the valve characteristics from the appropriate state greatly varies from cylinder to cylinder.

  In this case, by driving the control shaft in the axial direction so as to eliminate the above-mentioned deviation in one of the cylinders, the valve characteristic can be brought into an appropriate state only with the cylinder, but the valve characteristic is made into an appropriate state in the other cylinders. Therefore, it is inevitable that the combustion state in the cylinder will deteriorate.

  The present invention has been made in view of such circumstances, and its purpose is to provide a variation among the cylinders in the deviation of the valve characteristic of the engine valve from the appropriate state when the control shaft is thermally expanded in the axial direction. It is an object of the present invention to provide a variable valve operating apparatus for an internal combustion engine that can avoid the above-described problem.

In the following, means for achieving the above object and its effects are described.
In order to achieve the above object, according to the first aspect of the present invention, the variable valve lift mechanism provided for each cylinder of the internal combustion engine is provided between the plurality of vertical wall portions, and the adjacent valve lift variable mechanism is provided by the vertical wall portion. The variable valve lift mechanism is engaged with a control shaft extending through each cylinder and penetrating each standing wall, and is displaced in the axial direction based on driving of the shaft, and the slider In the variable valve operating apparatus for an internal combustion engine, the standing wall portion is provided with a variable drive unit that is engaged with the slider and driven to vary the valve characteristic of the engine valve based on the displacement of the slider in the axial direction. Can be moved in the axial direction through the control shaft and interposed between the variable drive portions in the variable valve lift mechanism of each cylinder. That an intermediate member, with a, a restricting means for performing the restriction and release of the restriction of the transmission of forces via the intermediate member to the variable drive unit of the next from a predetermined variable drive unit.

  According to the above configuration, when the slider of each cylinder engaged with the shaft is displaced in the axial direction along with the thermal expansion of the control shaft in the axial direction, the variable drive unit engaged with the slider is also moved to the slider. Along with this, it is displaced in the axial direction. In this way, the variable drive unit can be displaced along with the slider because the intermediate member interposed between the variable drive units of each cylinder is movable in the axial direction with respect to the standing wall portion. This is because the relative movement in the axial direction with respect to the standing wall portion of the variable drive unit is allowed through the movement of. Since the variable drive section of each cylinder is displaced in the axial direction along with the displacement of the corresponding slider, when the control shaft is thermally expanded in the axial direction, the axis of the slider and the variable drive section in each cylinder. The relative position with respect to the direction does not change, and the valve characteristic of the engine valve does not deviate from the proper state. Accordingly, the change in the relative position of the slider and the variable drive unit in the axial direction is different for each cylinder, and the occurrence of the phenomenon that the deviation of the valve characteristic of the engine valve from the appropriate state varies among the cylinders is also avoided. be able to.

  By the way, when the engine valve is lifted, the reaction force at that time acts on the variable drive section. The variable drive unit receives a force in the axial direction of the control shaft and is pressed against the intermediate member by the force due to the action of the reaction force described above from the relationship engaged with the slider. As a result, the force is transmitted to the variable drive unit of another cylinder via the intermediate member, and there is a possibility that elastic deformation such as bending occurs in the variable drive unit. Here, when the engine valve is lifted in the other cylinder, if elastic deformation such as bending occurs in the variable drive part of the cylinder, the lift characteristic (valve characteristic) of the engine valve changes from the appropriate state. However, the operation of the internal combustion engine is affected.

  However, according to the above-described configuration, when the engine valve is lifted, the transmission of the force via the intermediate member from the variable drive unit corresponding to the engine valve to the other variable drive unit is regulated by the regulating unit, This restriction can be released when the vehicle is not lifted. By using the restricting means in this way, it is possible to suppress the occurrence of elastic deformation such as bending in the variable drive portions of other cylinders through the transmission of force through the intermediate member when the engine valve is lifted. Therefore, when the engine valve is lifted in the other cylinder, elastic deformation such as the bending occurs in the variable drive part of the cylinder, and based on this, the valve characteristic of the engine valve changes from an appropriate state and affects the operation of the internal combustion engine. Can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the restricting means is a variable drive adjacent to the variable drive unit corresponding to the engine valve during a large lift period including the maximum lift time of the engine valve. The gist is to restrict the transmission of force to the part through the intermediate member.

  As the lift amount of the engine valve increases, the reaction force during the lift increases, and the force in the axial direction of the control shaft that the variable drive receives due to the reaction force also increases. When it is transmitted to the variable drive part of another cylinder via the, elastic deformation such as bending of the variable drive part becomes large. As a result, the valve characteristics of the engine valves of the other cylinders are greatly changed from the appropriate state, and the influence on the internal combustion engine is thereby increased. However, according to the above configuration, during the lift of the engine valve and during the large lift period in which the force is the largest, the intermediate member from the variable drive unit corresponding to the engine valve to another variable drive unit is interposed. Since the transmission of all the forces is restricted, it is possible to suppress a large change from the appropriate state of the valve characteristics described above and the influence on the internal combustion engine.

  According to a third aspect of the present invention, in the second aspect of the present invention, the restricting means is positioned on the transmission direction side of the force via the intermediate member even during a large lift period including the maximum lift time. If the engine valve of the cylinder to be operated is not being lifted, the regulation is not performed.

  Even if force is transmitted from the variable drive unit to another variable drive unit through the intermediate member during the large lift period, the engine valve is lifted by the cylinder located on the side of the force transmission direction. If not, even if the variable drive part of the cylinder receives the above-described force and undergoes elastic deformation such as bending, the operation of the internal combustion engine is not affected thereby. According to the above configuration, in such a case, the restriction of the transmission of the force via the intermediate member is not performed, so that the restriction is not performed wastefully.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the restricting means can approach and separate in a direction perpendicular to the axis of the control shaft with respect to the outer surface of the intermediate member. The gist of the invention is that it includes a pressing member and an actuator that presses the pressing member against the outer surface of the intermediate member.

  According to the above configuration, when the pressing member is pressed against the outer surface of the intermediate member by the actuator, the transmission of force from the variable drive unit to the other variable drive unit via the intermediate member is restricted. That is, when the pressing member is pressed against the outer surface of the intermediate member, the frictional force acting between them increases, and when the force is transmitted to the intermediate member, the force is canceled by the amount of the frictional force. Transmission will be regulated. In this way, the transmission of the force through the intermediate member can be accurately regulated.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to third aspects, the variable drive portion is an input arm that is pushed by a rotating cam and swings around the axis of the control shaft. And an output arm that lifts the engine valve by swinging about the axis along with the swing of the input arm, and changing the relative position of the input arm and the output arm with respect to the swing direction of the engine valve. The valve characteristic is variable, and the input arm and the output arm are engaged with the slider by meshing splines with different inclination directions, respectively, and the mutual displacement of the slider through the axial direction of the slider. The relative position with respect to the swinging direction is changed, and the restricting means is adapted to react with the reaction force at the time of lifting the engine valve. It was summarized in that the force acting in the axial direction with respect to the input arm and the output arm and performs the restriction by the action of reverse force to the intermediate member Te.

  According to the above configuration, when the engine valve is lifted, the force transmitted to the intermediate member via the input arm and the output arm based on the reaction force at that time is equivalent to the force applied to the intermediate member by the restricting means. This cancels out the transmission of force based on the reaction force via the intermediate member. In this way, the transmission of the force through the intermediate member can be accurately regulated.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the regulating means is configured such that the magnitude of the force acting on the intermediate member is a reaction force when the engine valve is lifted. The magnitude of the force applied to the intermediate member is adjusted in accordance with the lift amount of the engine valve so as to be equal to the force acting on the arm in the axial direction.

  According to the above configuration, the force transmitted to the intermediate member via the input arm and the output arm based on the reaction force at the time of lifting the engine valve is canceled by the force applied to the intermediate member by the restricting means. Therefore, it is possible to prevent transmission of force based on the reaction force through the intermediate member.

[First Embodiment]
Hereinafter, a first embodiment in which the present invention is applied to an in-line four-cylinder engine for an automobile will be described with reference to FIGS.

  FIG. 1 is an enlarged cross-sectional view showing a structure around a cylinder head 2 in a predetermined cylinder among the first to fourth cylinders of the engine 1. In this engine 1, a combustion chamber 6 is defined by a cylinder head 2, a cylinder block 3, and a piston 5, and an intake passage 7 and an exhaust passage 8 are connected to the combustion chamber 6 in a state of being branched into two. (Only one is shown in FIG. 1). The intake passage 7 and the combustion chamber 6 are connected and cut off by the opening / closing operation of the intake valve 9, and the exhaust passage 8 and the combustion chamber 6 are connected and cut off by the opening / closing operation of the exhaust valve 10. Two intake valves 9 and two exhaust valves 10 are provided for each cylinder.

  The cylinder head 2 is provided with an intake camshaft 11 and an exhaust camshaft 12 for driving the intake valve 9 and the exhaust valve 10. The intake camshaft 11 and the exhaust camshaft 12 rotate by transmission of rotation from the crankshaft of the engine 1. The intake camshaft 11 and the exhaust camshaft 12 are provided with an intake cam 11a and an exhaust cam 12a, respectively. The intake valve 9 and the exhaust valve 10 are opened and closed through integral rotation of the intake cam 11a and the exhaust cam 12a with the intake cam shaft 11 and the exhaust cam shaft 12.

  The engine 1 has a maximum lift amount of the intake valve 9 and an operating angle of the intake cam 11a (the operating angle of the intake valve 9) as a variable valve lift mechanism that changes the valve characteristics of the engine valves such as the intake valve 9 and the exhaust valve 10. A variable valve lift mechanism 14 is provided between the intake cam 11 a and the intake valve 9. Through the driving of the variable valve lift mechanism 14, for example, the maximum lift amount and the operating angle are controlled to increase as the engine operation state that requires a larger intake air amount is reached. This is because the larger the maximum lift amount and the operating angle, the more efficiently the air is sucked into the combustion chamber 6 from the intake passage 7 and the above-described requirements regarding the intake air amount can be satisfied.

Next, the detailed structure of the variable valve lift mechanism 14 will be described.
The variable valve lift mechanism 14 includes an input arm 17 that is pushed by the rotating intake cam 11 a and swings about the axes of the rocker shaft 15 and the control shaft 16 extending in parallel with the intake cam shaft 11, and the input arm 17 And an output arm 18 that swings about the axis based on the swing. A roller 19 is rotatably attached to the input arm 17. The input arm 17 is urged toward the intake cam 11a by the coil spring 20 so that the roller 19 is pressed against the intake cam 11a. Further, the output arm 18 is pressed against the rocker arm 21 when swinging, and lifts the intake valve 9 via the rocker arm 21.

  The base end portion of the rocker arm 21 is supported by a lash adjuster 22, and the distal end portion of the rocker arm 21 is in contact with the intake valve 9. The rocker arm 21 is urged toward the output arm 18 by the valve spring 24 of the intake valve 9, whereby a roller 23 rotatably supported between the base end portion and the distal end portion of the rocker arm 21 is applied to the output arm 18. It is pressed.

  Therefore, when the input arm 17 and the output arm 18 swing based on the rotation of the intake cam 11a, the output arm 18 lifts the intake valve 9 via the rocker arm 21, and the intake valve 9 is opened and closed. In the variable valve lift mechanism 14, the maximum lift amount of the intake valve 9 and the intake cam 11 a with respect to the intake valve 9 are changed by changing the relative positions of the input arm 17 and the output arm 18 in the swing direction. The working angle is variable. That is, as the input arm 17 and the output arm 18 are brought closer to each other in the swing direction, the maximum lift amount of the intake valve 9 and the operating angle of the intake cam 11a become smaller. Conversely, as the input arm 17 and the output arm 18 are separated from each other in the swinging direction, the maximum lift amount of the intake valve 9 and the operating angle of the intake cam 11a increase.

  Next, FIG. 2 shows the structure for attaching the variable valve lift mechanism 14 to the cylinder head 2 and the structure for attaching the rocker shaft 15 and the control shaft 16 used for driving the variable valve lift mechanism 14 to the cylinder head 2. The description will be given with reference.

FIG. 2 is a plan view of the cam carrier 41 formed on the upper portion of the cylinder head 2 as viewed from above.
The cam carrier 41 is provided with a plurality of standing wall portions 45 corresponding to each cylinder so as to be parallel to each other. These standing wall portions 45 are formed of a lightweight material such as an aluminum alloy in order to reduce the weight of the internal combustion engine. The variable valve lift mechanism 14 is disposed between the standing wall portions 45 corresponding to the cylinders of the internal combustion engine. Adjacent valve lift variable mechanisms 14 are separated by a standing wall 45. The rocker shaft 15 and the control shaft 16 used for driving the variable valve lift mechanism 14 pass through the variable valve lift mechanisms 14 and the standing wall portions 45. The variable valve lift mechanisms 14 are supported by the standing wall portions 45 via the rocker shaft 15. Further, the input arm 17 and the output arm 18 of the mechanism 14 are sandwiched between the standing wall portions 45.

  The rocker shaft 15 is formed in a pipe shape, and the control shaft 16 is supported inside the rocker shaft 15 so as to be reciprocally movable in the axial direction. Both the rocker shaft 15 and the control shaft 16 are formed by using a material having high strength such as an iron-based material with an emphasis on ensuring necessary strength. The control shaft 16 has a base end portion (left end portion in the figure) connected to the actuator 47 and is moved in the axial direction of the shaft 16 through the drive of the actuator 47. The variable valve lift mechanism 14 of each cylinder is driven through movement of the control shaft 16 in the axial direction, and changes the relative position of the input arm 17 and the output arm 18 in the swing direction.

Next, the internal structure of the variable valve lift mechanism 14 will be described with reference to FIGS.
FIG. 3 is a cutaway perspective view showing the inner structure of the input arm 17 and the output arm 18 in the variable valve lift mechanism 14.

  The variable valve lift mechanism 14 includes a cylindrical slider 26 disposed inside the input arm 17 and the output arm 18. The rocker shaft 15 is inserted into the slider 26, and the control shaft 16 is inserted into the rocker shaft 15. When the control shaft 16 moves in the axial direction, the movement is transmitted to the slider 26 by an engaging member (not shown in FIG. 3) attached to the control shaft 16, and the slider 26 also moves in the axial direction. Displace. On the outer wall of the slider 26, an input gear 27a having a helical spline 27 is fixed at the center in the longitudinal direction, and an output gear 29a having a helical spline 29 is fixed at both ends in the longitudinal direction.

  On the other hand, as shown in FIG. 4, an annular inner gear 28 a having a helical spline 28 is formed on the inner wall of the input arm 17, and an annular inner tooth having a helical spline 30 on the inner wall of the output arm 18. A gear 30a is formed. The internal gear 28a of the input arm 17 is meshed with the input gear 27a (FIG. 3) of the slider 26, and the internal gear 30a of the output arm 18 is meshed with the output gear 29a (FIG. 3) of the slider 26. The helical splines 27 and 28 and the helical splines 29 and 30 have different inclination angles, for example, the inclination directions of the tooth traces are opposite to each other.

  Then, when the slider 26 is displaced in the coaxial line direction based on the movement of the control shaft 16 in the axial direction, the input arm 17 and the output arm 18 swing due to the meshing of the helical splines 27 and 29 and the helical splines 28 and 30. The relative position with respect to the direction is changed. Specifically, as the slider 26 is displaced in the direction of arrow L in FIG. 3, the relative positions of the input arm 17 and the output arm 18 in the swinging direction are changed so as to approach each other, and the slider 26 is moved in the direction of arrow H. The relative positions are changed so as to be separated from each other as they are displaced. Through the change of the relative position of the input arm 17 and the output arm 18 in the swing direction, the maximum lift amount of the intake valve 9 and the working angle of the intake cam 11a when the output arm 18 swings due to the rotation of the intake cam 11a. Is variable. Therefore, in the variable valve lift mechanism 14, the input arm 17 and the output arm 18 serve as a variable drive unit that is driven to change the valve characteristic of the intake valve 9.

  Lubricating oil is supplied to the inside of the input arm 17 and the output arm 18 from an oil pump driven by the engine 1 via an oil passage, and the input arm 17, the output arm 18, the slider 26, and the like are fed by the lubricating oil. Lubricating between gears (splines) meshing with each other is performed.

FIG. 5 is a cross-sectional view showing the internal structure of the input arm 17, the output arm 18, the slider 26, the rocker shaft 15, and the like.
As shown in the figure, the rocker shaft 15 and the control shaft 16 for driving the variable valve lift mechanism 14 pass through a plurality of standing wall portions 45 provided in the cylinder head 2, and between these standing wall portions 45. The input arm 17 and the output arm 18 of the variable valve lift mechanism 14 located at the same position are also penetrated.

  The engagement of the slider 26 with the control shaft 16 is realized using an engagement member 61. The slider 26 and the control shaft 16 are connected by the engaging member 61 so as to be integrally movable in the axial direction of the control shaft 16. The engaging member 61 passes through the bush 35 inserted into the groove 34 formed to extend in the circumferential direction on the inner peripheral surface of the slider 26, and the elongated hole 33 of the rocker shaft 15 through the bush 35. In this state, a pin 51 is inserted into the control shaft 16 in the radial direction. The elongated hole 33 through which the pin 51 passes extends in the axial direction of the rocker shaft 15 (left and right direction in the figure). The elongated hole 33 and the pin 51 can only move relative to each other in the axial direction, and cannot move relative to the rocker shaft 15 in the circumferential direction.

  Accordingly, when the control shaft 16 moves in the axial direction, the pin 51 moves along the elongated hole 33 of the rocker shaft 15 accordingly. As a result, the pin 51 is pressed against the inner surface of the groove 34 via the outer surface of the bush 35, and the slider 26 is displaced in the axial direction of the control shaft 16. The relative position of the input arm 17 and the output arm 18 in the swing direction is variable through the displacement of the slider 26, and the input arm 17 and the output arm 18 swing due to the rotation of the intake cam 11a (FIG. 1). The maximum lift amount and operating angle of the intake valve 9 at that time are variable. When the input arm 17 and the output arm 18 swing, the slider 26 swings (rotates) in the circumferential direction accordingly. At this time, the inner surface of the groove 34 of the slider 26 slides with respect to the outer surface of the bush 35, and the bush 35 and the pin 51 also try to swing in the circumferential direction due to the frictional force therebetween. However, the rocking of the bush 35 and the pin 51 following the rocking of the slider 26 is regulated by the opposing inner surface of the elongated hole 33 of the rocker shaft 15.

  Next, thermal expansion of the control shaft 16 will be described with reference to FIG. In the figure, (a) schematically shows the state of the control shaft 16 before thermal expansion, and (b) schematically shows the state of the control shaft 16 after thermal expansion.

  When the control shaft 16 is not thermally expanded, the engagement position of the slider 26 by the engagement member 61 in each cylinder with respect to the shaft 16 is a position indicated by a black triangle (▼) in FIG. When the control shaft 16 expands in the axial direction during operation of the engine 1, the end portion (base end) on the side where the shaft 16 is connected to the actuator 47 as shown in FIG. It extends in the axial direction as a reference. Thereby, the engagement position is shifted from the position indicated by the black triangle in FIG. 6A to the position indicated by the black triangle in FIG. 6B. When the slider 26 deviates from the proper position in the axial direction as the engagement position deviates from the proper position, the relative position of the input arm 17 and the output arm 18 in the swinging direction is deviated. As described in the column “[Problems to be Solved by the Invention]”, the valve characteristic of No. 9 deviates from an appropriate state.

  The amount of deviation of the engagement position indicated by the black triangle in the figure from the appropriate position associated with the thermal expansion increases as the distance from the end of the control shaft 16 increases. More specifically, assuming that the shift amounts of the first cylinder to the fourth cylinder are respectively “z1”, “z2”, “z3”, and “z4”, the shift amounts z1 to z4 are “z1 <z2 <z3 <z4”. ”. This is because the distance to the engagement position with the end portion as the reference position increases in the order of the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder. That is, assuming that the distances in the first cylinder to the fourth cylinder are “x1”, “x2”, “x3”, and “x4”, respectively, the distances have a relationship of “x1 <x2 <x3 <x4” The amount of material of the control shaft 16 between the end and the engagement position increases in the order of cylinder, second cylinder, third cylinder, and fourth cylinder. As a result, the amount of thermal expansion in the axial direction of the control shaft 16 at the engagement position with the end as the reference position, in other words, the shift amounts z1 to z4 are the first cylinder, the second cylinder, the third cylinder, The number increases in the order of the fourth cylinder.

  Thus, since the displacements z1 to z4 have a relationship of “z1 <z2 <z3 <z4”, the cylinders located farther from the end, that is, the first cylinder, the second cylinder, the third cylinder The deviation from the appropriate state of the valve characteristics of the intake valve 9 increases in the order of the fourth cylinder. Here, assuming that the positions of the input arm 17 and the output arm 18 of each cylinder in the axial direction of the control shaft 16 are defined by the standing wall 45, the input arm 17 and the output arm 18 are thermally expanded by the standing wall 45. Is displaced in the axial direction. However, since there is a difference in thermal expansion coefficient due to a difference in material and a difference in installation mode between the control shaft 16 and the standing wall portion 45, each control cylinder 16 and the standing wall portion 45 has a different thermal expansion rate in each cylinder. It is unlikely that the input arm 17 and the output arm 18 positioned between the standing wall portions 45 are displaced in the axial direction by the same amount as the slider 26 corresponding thereto.

  Accordingly, when thermal expansion occurs in the control shaft 16 and the standing wall portion 45, a relative position change occurs in the axial direction between the slider 26 and the input arm 17 and the output arm 18, and the change in the relative position corresponds to each change. As a result, the deviation of the valve characteristic of the intake valve 9 from the appropriate state varies greatly from cylinder to cylinder. In this case, the control shaft 16 is driven in the axial direction in consideration of the deviation of the valve characteristic of one of the cylinders from the appropriate state, so that the above deviation in the cylinder can be eliminated. The valve characteristics will deviate from the proper state, and the combustion state in the cylinder may be deteriorated.

Next, a structure around the standing wall portion 45 for avoiding the above-described problems will be described with reference to FIG.
The standing wall portion 45 is formed by attaching a cam cap 43 made of a lightweight material such as an aluminum alloy to the upper side of a bearing 42 made of a lightweight material such as an aluminum alloy formed on the cylinder head 2 with a bolt 44. . A cylindrical collar 55 is provided between the bearing 42 and the cam cap 43 so as to extend in the axial direction of the control shaft 16. The collar 55 penetrates the upright wall 45 and can move in the axial direction with respect to the upright wall 45 and is interposed between the input arm 17 and the output arm 18 of each cylinder. Further, the rocker shaft 15 and the control shaft 16 are in a state of penetrating the collar 55.

  In the collar 55, the length in the center line direction is larger than the width of the standing wall portion 45 in the axial direction, and both end portions in the longitudinal direction are exposed to the outside of the standing wall portion 45. At both ends in the longitudinal direction of the collar 55, exposed portions 56 having a diameter larger than that of the portion located in the standing wall portion 45 are formed. A shim 57 for adjusting the positions of the input arm 17 and the output arm 18 in the axial direction is provided between the exposed portion 56 and the variable valve lift mechanism 14 (output arm 18). Further, a clearance C is formed between the exposed portion 56 and the standing wall portion 45, and the collar 55 can be displaced in the axial direction of the control shaft 16 by the clearance C. Therefore, the input arm 17 and the output arm 18 of each cylinder can be displaced in the axial direction of the control shaft 16 by at least the clearance C.

  Therefore, when the slider 26 (FIG. 5) of each cylinder engaged with the shaft 16 is displaced in the axial direction as the control shaft 16 is thermally expanded in the axial direction, the slider 26 is engaged with the slider 26 via a gear. The input arm 17 and the output arm 18 are also displaced in the axial direction along with the slider 26. The reason why the input arm 17 and the output arm 18 can be displaced along with the slider 26 is that the collar 55 can move in the axial direction by the clearance C, and the input through the movement of the collar 55. This is because relative movement of the arm 17 and the output arm 18 in the axial direction with respect to the standing wall portion 45 is allowed.

  Since the input arm 17 and the output arm 18 of each cylinder move in the axial direction along with the slider 26 as described above, when the control shaft 16 thermally expands in the axial direction, the slider 26 in each cylinder The relative positions of the input arm 17 and the output arm 18 in the axial direction do not change. Further, there is no possibility that the valve characteristic of the intake valve 9 is deviated from an appropriate state due to the change in the relative position. For this reason, changes in the relative positions of the slider 26, the input arm 17, and the output arm 18 in the axial direction are different for each cylinder, and the deviation of the valve characteristic of the intake valve 9 from the appropriate state varies among the cylinders. The occurrence of this phenomenon can be avoided.

  By the way, when the intake valve 9 is lifted, the reaction force at that time acts on the input arm 17 and the output arm 18. Since the input arm 17 and the output arm 18 are engaged with the slider 26 (FIG. 5) via a gear (spline), the control shaft 16 indicated by an arrow in FIG. And is pressed against the collar 55 on the arrow direction side by the force. As a result, the force is transmitted to the input arm 17 and the output arm 18 of other cylinders via the collar 55, and there is a possibility that elastic deformation such as bending occurs in the input arm 17 and the output arm 18. Here, when the intake valve 9 is lifted in the other cylinder, if elastic deformation such as bending occurs in the input arm 17 and the output arm 18 of the cylinder, the lift characteristic of the intake valve 9 of the cylinder is thereby caused. The (valve characteristic) changes from the appropriate state, and the operation of the engine 1 is affected.

  Therefore, in this embodiment, when the intake valve 9 is lifted, the force is transmitted from the input arm 17 and the output arm 18 corresponding to the valve 9 to the input arm 17 and the output arm 18 of another cylinder via the collar 55. To regulate. As a result, when the intake valve 9 is lifted, elastic deformation such as bending is suppressed from occurring in the input arm 17 and the output arm 18 of other cylinders through transmission of force through the collar 55. Accordingly, when the intake valve 9 in the other cylinder is lifted, the input arm 17 and the output arm 18 of the same cylinder undergo elastic deformation such as bending, and based on this, the valve characteristics of the intake valve 9 change from an appropriate state and the engine changes. The influence on the operating state of 1 can be suppressed.

Next, a device (regulating means) that regulates transmission of force through the collar 55 will be described.
In the standing wall portion 45 on the left side in the drawing, a pressing member 65 that can approach and separate from the collar 55 in a direction orthogonal to the axis of the control shaft 16 passes through the cam cap 43. The pressing member 65 is pressed against the outer peripheral surface (outer surface) of the collar 55 in the standing wall portion 45 by driving the actuator 66, and the pressing is released by stopping the driving of the actuator 66. It has become.

  The end surface on the collar 55 side of the pressing member 65 is curved in the same direction as the outer peripheral surface and has the same curvature so as to come into surface contact with the outer peripheral surface of the portion located in the standing wall portion 45 of the collar 55. It has become. As a material for forming the pressing member 65, it is preferable to select a material that can increase the frictional force between the end surface and the outer peripheral surface of the collar 55 when they are in contact with each other. As the actuator 66, for example, an electric type or a hydraulic type can be adopted.

  When the pressing member 65 is pressed against the collar 55 by the actuator 66 when the force is transmitted to the collar 55, the frictional force acting between the pressing member 65 and the collar 55 becomes large, and the amount of the frictional force is reduced. Only the force transmitted to the collar 55 is canceled out. Thereby, the transmission of the force through the collar 55 is restricted. Further, when the pressing of the pressing member 65 to the collar 55 by the actuator 66 is stopped, the frictional force between the pressing member 65 and the collar 55 becomes small (almost “0”), and the collar 55 is generated by the frictional force via the collar 55. All restrictions on the transmission of the force are released.

  The drive control of the actuator 66 is performed by an electronic control unit 69 mounted on the automobile so as to perform various controls such as drive control of the variable valve lift mechanism 14. That is, the electronic control unit 69 inputs detection signals from various sensors such as the crank position sensor 70 and the cam position sensor 71 used for detecting the crank angle and the cam angle. Further, the electronic control unit 69 inputs an operation angle signal from the actuator 47 that drives the variable valve lift mechanism 14, in other words, a signal corresponding to the valve opening period of the intake valve 9. The electronic control unit 69 performs drive control of the actuator 66 based on the engine state grasped from the detection signals from the various sensors and the operating angle signal of the actuator 47 described above.

  Next, an installation aspect of the above-described device that restricts transmission of force through the collar 55 will be described with reference to FIG. 8, (a) is a schematic diagram showing the arrangement of each cylinder in the engine 1, and (b) is a timing chart showing the transition of the lift amount of the intake valve 9 of each cylinder with respect to the change of the crank angle.

  As shown in FIG. 8 (a), in the engine 1, the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder are arranged in a line from left to right in the drawing in that order. ing. Further, when the intake valve 9 of each cylinder is lifted, a force based on the reaction force at that time acts on the input arm 17 and the output arm 18 in the variable valve lift mechanism 14 of the cylinder in the direction of the arrow in the figure. Further, as shown in FIG. 8B, the intake valve 9 of each cylinder lifts in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder with respect to the change in the crank angle.

Here, the transmission of the force through the collar 55 causes a problem when the following conditions are satisfied.
The cylinder in which the intake valve 9 is being lifted in a predetermined cylinder and the intake valve 9 is scheduled to be lifted next is the transmission direction side of the force with respect to the predetermined cylinder (the arrow direction side in FIG. 8A). The cylinder is located in

During the lift of the intake valve 9 in the predetermined cylinder, the intake valve 9 starts to lift in the cylinder that the intake valve 9 is scheduled to lift next.
Then, the situations shown in the following [1] and [2] can be given as situations where these conditions can be satisfied.

  [1] During the lift of the intake valve 9 of the first cylinder, when the intake valve 9 starts to lift in the third cylinder where the intake valve 9 is scheduled to lift next, in other words, in the first cylinder and the third cylinder When the valve opening periods of the intake valve 9 overlap.

  In this case, during the lift of the intake valve 9 of the first cylinder, if a force based on the reaction force at that time acts on the input arm 17 and the output arm 18 of the first cylinder as indicated by arrows in FIG. The collar 55 between the first cylinder and the second cylinder is pushed in the direction of the arrow by the input arm 17 and the output arm 18. When the force is transmitted in the direction of the arrow through the collar 55, the force is transmitted through the input arm 17 and the output arm 18 of the second cylinder, and the collar 55 between the second and third cylinders. It is transmitted to the input arm 17 and the output arm 18 of the third cylinder. As a result, elastic deformation such as bending occurs in the input arm 17 and the output arm 18 of the third cylinder, and the valve characteristic of the intake valve 9 that is being lifted in the same cylinder changes from an appropriate state.

  At this time, the input arm 17 and the output arm 18 of the second cylinder also undergo elastic deformation such as bending due to the transmission of the force. However, since the intake valve 9 is not lifted in the second cylinder, Elastic deformation such as bending of the input arm 17 and the output arm 18 in the cylinder does not affect the valve characteristics of the intake valve 9 in the cylinder.

  [2] During the lift of the intake valve 9 of the third cylinder, when the intake valve 9 starts to lift in the fourth cylinder where the intake valve 9 is scheduled to be lifted next, in other words, in the third cylinder and the fourth cylinder When the valve opening periods of the intake valve 9 overlap.

  In this case, during the lift of the intake valve 9 of the third cylinder, if a force based on the reaction force at that time acts on the input arm 17 and the output arm 18 of the third cylinder as shown by arrows in FIG. The collar 55 between the third cylinder and the fourth cylinder is pushed in the direction of the arrow by the input arm 17 and the output arm 18. When the force is transmitted in the arrow direction through the collar 55, the force is transmitted to the input arm 17 and the output arm 18 of the fourth cylinder. As a result, elastic deformation such as bending occurs in the input arm 17 and the output arm 18 of the fourth cylinder, and the valve characteristic of the intake valve 9 that is being lifted in the same cylinder changes from an appropriate state.

  In consideration of the above, the pressing member 65 and the actuator 66 for restricting the transmission of the force through the collar 55 are the standing wall portion 45 between the first cylinder and the second cylinder, and the third cylinder and the fourth cylinder. It is provided only on the standing wall 45 between the cylinder. FIG. 7 shows the pressing member 65 and the actuator 66 provided on the standing wall portion 45 between the third cylinder and the fourth cylinder. Further, the reason why the pressing member 65 and the actuator 66 are not provided on the standing wall portions 45 other than the standing wall portions 45 is as follows. That is, when the intake valve 9 is lifted in the second cylinder and the fourth cylinder, the above-described conditions that cause a problem in the transmission of the force through the collar 55 are not satisfied. Therefore, even if the pressing member 65 and the actuator 66 for restricting the transmission of the force are provided on the standing wall portions 45 other than the above-described standing wall portion 45, restricting the transmission of the force by them suppresses the above problems. This is because it is meaningless.

Next, drive control of the actuator 66 by the electronic control unit 69 will be described by taking as an example the case where the intake valves 9 of the third cylinder and the fourth cylinder are lifted.
During the lift of the intake valve 9 of the third cylinder, the force based on the reaction force becomes the largest during the period before and after the maximum lift including the maximum lift of the intake valve 9, that is, the large lift shown in FIG. Period T is in progress. Then, after the lift of the intake valve 9 of the third cylinder is started, the lift of the intake valve 9 of the fourth cylinder is started.

  The valve characteristics of the intake valves 9 are variable through driving of the variable valve lift mechanism 14. That is, when the variable valve lift mechanism 14 is driven, the valve characteristic indicated by the solid line in FIG. 10 in the intake valve 9 changes as indicated by the arrow Y4, and the maximum lift amount and operating angle of the valve 9 change. It becomes like this. Accordingly, when the maximum lift amount and the operating angle of the intake valve 9 are increased through the drive of the variable valve lift mechanism 14, the fourth cylinder during the large lift period T of the intake valve 9 in the third cylinder. The intake valve 9 may start to lift.

The large lift period T described above is set in advance so as to satisfy the following conditions.
When the intake valve 9 starts to lift in the cylinder where the intake valve 9 is to be lifted next during the large lift period T, the input arm 17 and the output arm 18 of the cylinder start from the cylinder side during the large lift period T. The force based on the reaction force received increases to such an extent that elastic deformation such as bending occurs in the input arm 17 and the output arm 18. That is, the force based on the reaction force increases to such an extent that the valve characteristic of the intake valve 9 in the cylinder to which the intake valve 9 is scheduled to lift next is changed from the appropriate state.

  When the intake valve 9 starts to lift during the lift of the intake valve 9 during the lift of the intake valve 9 other than during the large lift period T, the input arm 17 and the output arm 18 of the cylinder start a large lift. The reaction force received from the cylinder side during the period T does not increase to such an extent that the input arm 17 and the output arm 18 cause elastic deformation such as bending. That is, the force based on the reaction force does not increase to the extent that the valve characteristic of the intake valve 9 in the cylinder to which the intake valve 9 is scheduled to lift next changes from the appropriate state.

The electronic control unit 69 performs the following two determination processes.
Based on the crank angle and the cam angle, it is determined whether or not the large lift period T is in the first cylinder or the third cylinder (third cylinder in the example of FIG. 9).

  Based on the operating state of the variable valve lift mechanism 14, the opening of the intake valve 9 in the cylinder where the lift of the intake valve 9 is scheduled to start next (the fourth cylinder in the example of FIG. 9) It is determined whether or not it is performed during T.

  If an affirmative determination is made in these two determination processes, the electronic control unit 69 presses the pressing member 65 against the collar 55 through driving of the actuator 66. Thereby, the frictional force between the pressing member 65 and the collar 55 becomes large, and the transmission of force based on the reaction force via the collar 55 is regulated through the action of the frictional force.

  In the example of FIG. 9, the transmission of the force is restricted with respect to the collar 55 between the third cylinder and the fourth cylinder, and the force with respect to the collar 55 between the first cylinder and the second cylinder is controlled. There are no restrictions on transmission. Further, when both of the above two determination processes make an affirmative determination during the lift of the intake valve 9 in the first cylinder, the transmission of the force with respect to the collar 55 between the first cylinder and the second cylinder is restricted. The force transmission is not restricted for the collar 55 between the third and fourth cylinders.

  On the other hand, if a negative determination is made in either of the two determination processes, the electronic control unit 69 stops driving the actuator 66 and stops pressing the pressing member 65 against the collar 55. As a result, the frictional force between the pressing member 65 and the collar 55 becomes small (almost “0”), and the restriction of the transmission of the force via the collar 55 is released.

According to the embodiment described in detail above, the following effects can be obtained.
(1) A collar 55 is interposed between the input arm 17 and the output arm 18 in the variable valve lift mechanism 14 of each cylinder, and the collar 55 can move relative to the standing wall 45 in the axial direction of the control shaft 16. Yes. Therefore, when the control shaft 16 is thermally expanded in the axial direction and the slider 26 is similarly displaced in the axial direction, the input arm 17 and the output arm 18 engaged with the slider 26 are also displaced in the axial direction. For this reason, the relative position of the slider 26, the input arm 17 and the output arm 18 in each cylinder in the axial direction does not change, and the valve characteristic of the intake valve 9 due to the change in the relative position is appropriate. There will be no deviation. Therefore, the change in the relative position of the slider 26, the input arm 17 and the output arm 18 in the axial direction differs for each cylinder, and the deviation of the valve characteristic of the intake valve 9 from the appropriate state varies among the cylinders. Occurrence of the phenomenon can be avoided.

  (2) When the intake valve 9 is lifted, a force based on the reaction force at that time acts on the input arm 17 and the output arm 18 corresponding to the valve 9 in the direction of the arrow in FIG. However, the transmission of the force from the input arm 17 and the output arm 18 to the input arm 17 and the output arm 18 of other cylinders via the collar 55 is restricted. Therefore, when the intake valve 9 in the other cylinder is lifted, elastic deformation such as bending occurs in the input arm 17 and the output arm 18 of the same cylinder, and the valve characteristics of the intake valve 9 change from an appropriate state based on the elastic deformation. The influence on the operating state of 1 can be suppressed. In addition, when the intake valve 9 is not lifted, the restriction on the transmission of the force through the collar 55 is released, and the restriction inhibits the movement of the collar 55 in the axial direction of the control shaft 16, and the above (1 ) Can no longer be obtained.

  (3) As the lift amount of the intake valve 9 increases, the force acting on the input arm 17 and the output arm 18 in the direction of the arrow in FIG. When the force is transmitted to the input arm 17 and the output arm 18 of other cylinders via the, elastic deformation such as bending of the arms 17 and 18 becomes large. As a result, the valve characteristics of the intake valves 9 of the other cylinders are greatly changed from the appropriate state, and the influence on the engine 1 is thereby increased. However, during a period before and after the maximum lift including the maximum lift of the intake valve 9 (a large lift period T), the input arm 17 and the output arm 18 corresponding to the intake valve 9 to the input arm 17 of another cylinder. And the transmission of the force based on the reaction force through the collar 55 to the output arm 18 is restricted. For this reason, the big change from the appropriate state of the valve characteristic mentioned above, and the influence on the engine 1 by it can be suppressed.

  (4) Even if the force is transmitted from the input arm 17 and the output arm 18 to the input arm 17 and the output arm 18 of another cylinder through the collar 55 during the large lift period T, the direction of the force transmission If the intake valve 9 is not lifted in the cylinder located on the side, transmission of the force through the collar 55 is not restricted. Here, even if the force is transmitted through the collar 55 and the input arm 17 and the output arm 18 of the cylinder located on the force transmission direction side receive the force, and elastic deformation such as bending occurs. If the intake valve 9 of the cylinder is not lifted at that time, the operation of the engine 1 is not affected. Therefore, by restricting the transmission of the force through the collar 55 as described above, the restriction is not wastefully performed.

  (5) The transmission of the force through the collar 55 is regulated by the actuator 66 in a direction perpendicular to the axis of the control shaft 16 with respect to the outer peripheral surface of the portion where the pressing member 65 is located in the standing wall 45 in the collar 55. Realized by pressing. That is, when the pressing member 65 is pressed against the outer peripheral surface of the collar 55 as described above, the frictional force acting between them becomes large, and when the force is transmitted to the collar 55, the force is increased by the amount of the frictional force. Because it is countered, the transmission of that force is regulated. In this way, the transmission of the force through the collar 55 can be accurately regulated.

  (6) The end surface of the pressing member 65 on the collar 55 side is a curved surface that is curved in the same direction as the outer peripheral surface of the portion of the collar 55 located in the standing wall portion 45 and has the same curvature. For this reason, when the pressing member 65 is pressed against the collar 55 by the actuator 66, the pressing member 65 and the collar 55 come into surface contact so that the frictional force acting between them can be accurately increased. Become.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In this embodiment, instead of realizing the restriction of the transmission of force through the collar 55 by pressing the pressing member 65 against the collar 55 in the direction perpendicular to the axis of the control shaft 16 as in the first embodiment. This is realized by applying a force to the collar 55 in the direction in which the axis extends.

  In this embodiment, as shown in FIG. 11, an arm 67 hits the wall surface on the action direction side (the arrow direction front side) of the force based on the reaction force in the exposed portion 56 of the collar 55. The actuator 66 can be moved in the axial direction of the control shaft 16. Then, by driving the actuator 66 through the arm 67 to push the collar 55 in the direction opposite to the arrow direction, a force in the direction opposite to the direction of the force based on the reaction force is applied to the collar 55. By applying the force to the collar 55 by driving the actuator 66 during the large lift period T, even if the force based on the reaction force is transmitted to the collar 55, the force is driven by the actuator 66. It is countered by the amount of power applied to. Thereby, the transmission of force based on the reaction force through the collar 55 is restricted.

  As described above, the drive control of the actuator 66 when the transmission of force is restricted is performed by the electronic control unit 69 as follows, for example. That is, the electronic control unit 69 estimates the lift characteristic of the intake valve 9 that is the source of the force based on the crank angle, the cam angle, the operation angle signal of the intake valve 9, and the like. Then, the electronic control unit 69 changes the crank angle so that the magnitude of the force applied to the collar 55 by the actuator 66 is equal to the force based on the reaction force acting on the collar 55. The actuator 66 is driven based on the lift amount of the intake valve 9.

In this embodiment, in addition to the effects (1) to (4) described in the first embodiment, the following effects can be obtained.
(7) Even if a force based on the reaction force is transmitted to the collar 55 during the large lift period T, the force is canceled by the amount of the force applied to the collar 55 by driving the actuator 66. In this way, the transmission of force based on the reaction force via the collar 55 can be accurately regulated.

  (8) The magnitude of the force applied to the collar 55 by the actuator 66 is made equal to the force based on the reaction force acting on the collar 55. As a result, the force based on the reaction force acting on the collar 55 is offset by the force applied to the collar 55 by the actuator 66, so that the transmission of the force based on the reaction force via the collar 55 does not occur. can do.

[Other Embodiments]
In addition, each said embodiment can also be changed as follows, for example.
-In 1st Embodiment, you may change suitably the shape of the end surface at the side of the collar 55 in the press member 65 to shapes other than a curved surface. For example, in order to simplify the processing of the end surface, the shape of the end surface can be a planar shape.

In the second embodiment, the magnitude of the force applied to the collar 55 by the actuator 66 may be constant at an optimum value determined in advance through experiments or the like.
In the first and second embodiments, the control shaft 16 is driven to rotate about its axis, and the engaging member that engages the shaft 16 and the slider 26 is used as the rotational movement of the control shaft 16 for the slider 26. It is good also as what converts into the said linear motion about the said axial direction. Specifically, the engaging member is engaged with a male screw formed on the outer peripheral surface of the control shaft 16, and the displacement of the engaging member in the circumferential direction accompanying the rotational movement of the control shaft 16 is prohibited. In this case, when the control shaft 16 rotates, the engaging member that meshes with the male screw of the shaft 16 is displaced in the axial direction to push the slider 26 in the axial direction, and the slider 26 is displaced in the axial direction. .

  -In 1st and 2nd embodiment, you may apply this invention to the variable valve apparatus which makes the valve characteristic of an exhaust valve variable.

The expanded sectional view which shows the structure around the cylinder head of the engine to which the variable valve apparatus of 1st Embodiment is applied. The top view which shows the cam carrier of a cylinder head. The fracture | rupture perspective view which shows the internal structure of a valve lift variable mechanism. The fracture | rupture perspective view which shows the internal structure of an input arm and an output arm. Sectional drawing which shows internal structures, such as an input arm, an output arm, a slider, and a rocker shaft. (A) And (b) is a schematic diagram which shows the thermal expansion aspect about the axial direction in a control shaft. Sectional drawing which shows the structure around the standing wall part in a cylinder head. (A) is a schematic diagram showing the arrangement of each cylinder in the engine, (b) is a timing chart showing the transition of the lift amount of the intake valve of each cylinder with respect to the change of the crank angle. The timing chart which shows transition of the lift amount of the intake valve of the 3rd cylinder and the 4th cylinder with respect to the change of a crank angle. The timing chart which shows the change of transition of the lift amount of an intake valve by the drive of a valve lift variable mechanism. Sectional drawing which shows the structure around the standing wall part of the cylinder head in the variable valve apparatus of 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder head, 3 ... Cylinder block, 5 ... Piston, 6 ... Combustion chamber, 7 ... Intake passage, 8 ... Exhaust passage, 9 ... Intake valve, 10 ... Exhaust valve, 11 ... Intake camshaft, 11a DESCRIPTION OF SYMBOLS ... Intake cam, 12 ... Exhaust cam shaft, 12a ... Exhaust cam, 14 ... Valve lift variable mechanism, 15 ... Rocker shaft, 16 ... Control shaft, 17 ... Input arm, 18 ... Output arm, 19 ... Roller, 20 ... Coil spring , 21 ... Rocker arm, 22 ... Rush adjuster, 23 ... Roller, 24 ... Valve spring, 26 ... Slider, 27 ... Helical spline, 27a ... Input gear, 28 ... Helical spline, 28a ... Internal gear, 29 ... Helical spline, 29a ... Output gear, 30 ... Helical spline, 30a ... Internal gear, 33 ... Elongated hole 34 ... Groove, 35 ... Bush, 41 ... Cam carrier, 42 ... Bearing, 43 ... Cam cap, 44 ... Bolt, 45 ... Standing wall, 47 ... Actuator, 51 ... Pin, 55 ... Collar (intermediate member), 56 ... Exposure Reference numeral 57: Shim 61: Engaging member 65: Pressing member 66 ... Actuator 67 ... Arm 69: Electronic control unit 70: Crank position sensor 71: Cam position sensor

Claims (6)

A variable valve lift mechanism provided for each cylinder of the internal combustion engine is provided between the plurality of standing wall portions and separated from the adjacent valve lift variable mechanism by the standing wall portion, and the variable valve lift mechanism is provided for each cylinder. And a slider that is engaged with a control shaft extending through the standing wall and is displaced in the axial direction based on driving of the shaft, and a displacement of the slider that is engaged with the slider in the axial direction. A variable valve operating device for an internal combustion engine comprising a variable drive unit that is driven to vary the valve characteristic of the engine valve based on
An intermediate member that passes through the standing wall portion in the axial direction of the control shaft and is movable in the axial direction, and is interposed between the variable drive portions in the variable valve lift mechanism of each cylinder;
Restriction means for restricting transmission of force through the intermediate member from a predetermined variable drive part to an adjacent variable drive part and releasing the restriction;
A variable valve operating apparatus for an internal combustion engine, comprising: The restricting means restricts transmission of force from the variable drive unit corresponding to the engine valve to the adjacent variable drive unit via the intermediate member during a large lift period including the maximum lift of the engine valve. The variable valve operating apparatus for an internal combustion engine according to claim 1. The restriction device does not perform the restriction unless the engine valve of the cylinder located on the transmission direction side of the force through the intermediate member is lifted even during the large lift period. The variable valve operating apparatus for an internal combustion engine. The restricting means includes a pressing member that can approach and separate from an outer surface of the intermediate member in a direction orthogonal to an axis of the control shaft, and an actuator that presses the pressing member against the outer surface of the intermediate member. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 3. The variable drive unit is an input arm that is pushed by a rotating cam and swings about the axis of the control shaft, and an output that swings about the axis along with the swing of the input arm and lifts the engine valve. And the valve characteristics of the engine valve are made variable by changing the relative positions of the input arm and the output arm in the swinging direction.
The input arm and the output arm are engaged with the slider by meshing splines with different inclination directions, and the relative positions in the swinging direction are changed through displacement of the slider in the axial direction. It has become something
The restricting means acts on the intermediate member by applying a force in the direction opposite to the force acting in the axial direction to the input arm and the output arm as a reaction force at the time of lifting the engine valve. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 3. The restricting means is configured so that a magnitude of a force acting on the intermediate member is equal to a force acting in the axial direction on the input arm and the output arm as a reaction force at the time of lifting of the engine valve. The variable valve operating apparatus for an internal combustion engine according to claim 5, wherein a magnitude of a force applied to the intermediate member is adjusted according to a lift amount of the valve.

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