JP4144530B2 - Variable valve mechanism for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve mechanism for an internal combustion engine that varies the valve characteristics of an intake valve or an exhaust valve of the internal combustion engine.

  Conventionally, as this type of variable valve mechanism, the following is known (see, for example, Patent Document 1). As shown in FIG. 11A, this variable valve mechanism includes a camshaft 161 and a rotating cam 162 provided on the camshaft 161, and a total of four variable valve mechanisms provided for each cylinder 164 of the cylinder head 163. The mediation drive mechanism 170 is provided. The intermediary drive mechanism 170 is disposed coaxially with the input cam 171 to which the valve drive force is input, the swing cam 172 that outputs the valve drive force to the valve side, and the input cam 171 and the swing cam 172. A control shaft 173 and a rocker shaft 175 are provided. Each input cam 171 and the swing cam 172 are respectively disposed between the pair of standing wall portions 174. As shown in FIG. 11B, the standing wall portion 174 includes a cam carrier 174a formed integrally with the cylinder head 163, and a cam cap 174b attached on the cam carrier 174a. The rocker shaft 175 is supported by a cam carrier 174a and a cam cap 174b.

Then, the control shaft 173 is driven in the axial direction by the lift amount variable actuator 165 to change the rotational phase difference between the input cam 171 and the two swing cams 172 in the mediation drive mechanism 170. Thereby, the valve characteristics such as the valve lift amount are adjusted to control the load and combustion state of the internal combustion engine.
JP 2001-263015 A

  By the way, in the variable valve mechanism, when the mediation drive mechanism 170 is assembled to the control shaft 173 and the rocker shaft 175, the input cam 171 and the outer periphery of four slider gears (not shown) fixed in advance to the rocker shaft 175, respectively. Both swing cams 172 are extrapolated. Therefore, it is difficult to unify the relative position of the nose 172a of the swing cam 172 with respect to the roller 171a of the input cam 171 over the entire intermediary drive mechanism 170. That is, it is difficult to finely adjust the relative positions of the cams 171 and 172 with respect to the control shaft 173 (slider gear), and the respective holding positions are not unified, and variations occur. When such a variation occurs, the rotational phase difference between the input cam 171 and the two swing cams 172 is shifted over the entire intermediary drive mechanism 170, and accordingly, each valve lift amount is ineffective. It will be uniform.

  Therefore, as shown in FIG. 11B, the positions of the input cam 171 and the two swing cams 172 with respect to the control shaft 173 are set by inserting plate members 176 between the cam cap 174b and the swing cam 172, respectively. It is conceivable to make the relative position uniform by adjusting. Here, since the cam cap 174b is co-ground in a state of being aligned with the cam carrier 174a in order to facilitate the manufacture thereof, the cam cap 174b has substantially the same shape and is formed with substantially the same thickness. It is common. In such a configuration, the plate material 176 is abutted and supported by the cam cap 174b, and the positions of the input cam 171 and the two swing cams 172 are adjusted via the plate material 176 with reference to the cam cap 174b. That is, the position adjustment of the input cam 171 and the two swing cams 172 is greatly affected by the mounting position of the cam cap 174b that can be attached to and detached from the cam carrier 174a in addition to the cam carrier 174a. Therefore, strict positioning of the cam cap 174b with respect to the cam carrier 174a is required. Therefore, it has been extremely difficult to accurately adjust the positions of the input cam 171 and both swing cams 172 with respect to the control shaft 173 (slider gear), that is, to adjust the mechanism for changing the valve characteristics.

  The present invention has been made paying attention to such problems existing in the prior art. It is an object of the present invention to provide a variable valve mechanism for an internal combustion engine that can accurately adjust a mechanism for changing valve characteristics.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
According to the first aspect of the present invention, in the cylinder head of the internal combustion engine, an input unit that is driven by a valve driving force from the cam side, and an output unit that outputs the valve driving force transmitted from the input unit to the valve side. An internal combustion engine including a control shaft arranged coaxially with the input unit and the output unit, and adjusting a valve characteristic by changing a rotational phase difference between the input unit and the output unit by axial movement of the control shaft The control valve is supported by an upright wall portion integrally formed with the cylinder head and a fixed portion attached to the upright wall portion, and is adjacent to the upright wall portion and the fixed portion. The input unit or the output unit is disposed at a position, and a shim plate is fitted between the input unit or the output unit and the standing wall, and the shim plate It is intended to align the input and the output unit with respect to preparative, and summarized in that formed by gap formed between the shim plate and the fixing unit.

  According to the above configuration, the shim plate is abutted and supported by the standing wall portion in a state of being separated from the fixed portion, and the input portion and the output portion are aligned with respect to the control shaft with reference to the standing wall portion. In other words, this shim plate does not contact the fixing portion that is appropriately attached to the standing wall portion when the control shaft is assembled to the cylinder head, and the input portion and the output portion are aligned without being affected by the fixing portion. To be done. For this reason, even if a slight shift occurs in the mounting position of the fixed portion, the shim plate abuts against the standing wall portion, so that the proper position adjustment of the input portion and the output portion with respect to the control shaft can be performed based only on the standing wall portion. Easy to do. That is, it is possible to accurately adjust the mechanism that makes the valve characteristics variable.

  According to a second aspect of the present invention, in the variable valve mechanism of the internal combustion engine according to the first aspect, the fixed portion is thinner in the axial direction of the control shaft than the standing wall portion. The gist is that it is formed. According to this configuration, the gap between the shim plate and the fixed portion can be easily provided.

Hereinafter, an embodiment in which a variable valve mechanism of the present invention is applied to a gasoline engine (hereinafter simply referred to as an engine) as an internal combustion engine will be described with reference to FIGS.
FIG. 1 shows a configuration of a variable valve mechanism in the engine 2. FIG. 2 is a plan view for explaining the upper structure of the engine 2.

  The engine 2 is mounted on the vehicle for driving the vehicle. The engine 2 includes a cylinder block 4, a piston 6 that reciprocates within the cylinder block 4, a cylinder head 8 that is mounted on the cylinder block 4, and the like. Four cylinders 2 a are formed in the cylinder block 4, and a combustion chamber 10 partitioned by the cylinder block 4, the piston 6 and the cylinder head 8 is formed in each cylinder 2 a. Each combustion chamber 10 is provided with four valves, two intake valves 12a and 12b and two exhaust valves 16a and 16b. The intake valves 12a and 12b open and close the intake port 14, and the exhaust valves 16a and 16b open and close the exhaust port 18.

  The intake port 14 of each cylinder 2a is connected to a surge tank via an intake passage formed in the intake manifold, and supplies air from the surge tank to each cylinder 2a via an air cleaner. A fuel injector is disposed in each intake passage so as to inject fuel into the intake port 14 of each cylinder 2a.

  The lift drive of the intake valves 12a and 12b is transmitted through the intermediate drive mechanism 120 and the roller rocker arm 52 disposed in the cylinder head 8 to transmit the valve drive force of the intake cam 45a provided on the intake camshaft 45. Is possible.

  The exhaust valves 16a and 16b of each cylinder 2a are opened and closed by a constant valve lift amount via a roller rocker arm 54 by an exhaust cam 46a provided on an exhaust camshaft 46 that rotates in conjunction with the rotation of the engine 2. Yes. And each exhaust port 18 of each cylinder 2a is connected with the exhaust manifold, and exhausts it outside.

  Next, the variable valve mechanism of the intake valves 12a and 12b will be described. This variable valve mechanism includes a total of four intermediary drive mechanisms 120 provided for each cylinder 2 a, a variable lift amount actuator 100 attached to one end of the cylinder head 8, and a rotation attached to the other end of the cylinder head 8. The phase difference variable actuator 104 and the like are provided.

  First, the mediation drive mechanism 120 will be described. FIG. 3 is a perspective view showing a state in which one of the mediation drive mechanisms 120 is horizontally broken. The intermediary drive mechanism 120 includes an input portion 122 provided in the center of the drawing, a first swing cam 124 as an output portion provided on the left side of the drawing, and a second swing cam 126 provided on the right side of the drawing. The housing 122a of the input portion 122 and the housings 124a and 126a of both the swing cams 124 and 126 have a cylindrical shape with the same outer diameter.

  FIG. 4 is a perspective view of the input unit 122. On the inner peripheral surface of the housing 122a of the input portion 122, there is provided a helical spline 122b formed in a right-handed spiral shape in the axial direction. Further, two parallel arms 122c and 122d project from the outer peripheral surface of the housing 122a. A shaft 122e parallel to the axial direction of the housing 122a is stretched around the ends of the arms 122c and 122d, and a roller 122f is rotatably attached. The roller 122f is urged so as to always come into contact with the intake cam 45a when the arms 122c and 122d are lifted by the spring 122g (see FIG. 1).

  FIG. 5 is a perspective view of the first swing cam 124. On the inner peripheral surface of the housing 124a of the first swing cam 124, there is provided a helical spline 124b formed in a spiral shape of a left-hand thread in the axial direction. The left end of the internal space of the housing 124a is covered with a ring-shaped bearing portion 124c having a center hole with a small diameter (see FIG. 3). A substantially triangular nose 124d protrudes from the outer peripheral surface of the housing 124a, and a cam surface 124e curved in a concave shape is provided on one side thereof.

  On the other hand, as shown in FIG. 3, on the inner peripheral surface of the housing 126a of the second swing cam 126, a helical spline 126b formed in a spiral shape of a left-hand screw is provided in the axial direction. The right end of the internal space of the housing 126a is covered with a ring-shaped bearing portion 126c having a center hole with a small diameter. A substantially triangular nose 126d protrudes from the outer peripheral surface of the housing 126a of the second swing cam 126, and a cam surface 126e that curves in a concave shape is provided on one side thereof. In a state in which the mediation drive mechanism 120 is attached to the cylinder head 8, the second swing cam 126 comes into contact with the side surface of the standing wall portion 138 on the bearing portion 126c side. This prevents the mediating drive mechanism 120 from moving to the right side in the figure along the axial direction (see FIG. 2).

  The first rocking cam 124 and the second rocking cam 126 are arranged so that the bearing portions 124c and 126c are outside and the respective end faces are coaxially in contact with the input portion 122 from both sides, and the whole is substantially the same. It becomes cylindrical (see FIG. 3).

  A slider gear 128 is disposed in the internal space formed by the input unit 122 and the swing cams 124 and 126 (see FIG. 3). The slider gear 128 has a substantially cylindrical shape, and includes an input helical spline 128a formed in a spiral shape of a right-hand thread at the center of the outer peripheral surface. The torsion angle of the input helical spline 128a is the same as the torsion angle of the helical spline 122b of the input unit 122.

  A first output helical spline 128c is provided at the left end portion of the input helical spline 128a with a small diameter portion 128b interposed therebetween, and a second output helical spline 128e is provided at the right end portion with a small diameter portion 128d interposed therebetween. . Both output helical splines 128c and 128e are formed in a left-handed spiral shape, and their torsion angles are the same as the torsion angles of the corresponding helical splines 124b and 126b of the swing cams 124 and 126, respectively. These output helical splines 128c and 128e have a smaller outer diameter than the input helical spline 128a.

  In addition, a through hole 128f is formed in the slider gear 128 in the axial direction, and one (right) small-diameter portion 128d is engaged with the tip of a locking pin 132a described later in the axial direction. The long hole 128g is formed.

  A pipe-like rocker shaft 130 shown in FIG. 6 is slidably disposed in the through hole 128f of the slider gear 128. One rocker shaft 130 is provided in common to all the mediation drive mechanisms 120 (four in this embodiment) (see FIG. 2). The rocker shaft 130 is provided with a long hole 130a that is elongated in the axial direction for each intermediate drive mechanism 120.

  A control shaft 132 that can slide in the axial direction is disposed in the rocker shaft 130. Similarly to the rocker shaft 130, the control shaft 132 is provided in common for all the mediating drive mechanisms 120. A locking pin 132 a protrudes from the control shaft 132 for each intermediate drive mechanism 120. The locking pin 132 a is formed so as to penetrate the long hole 130 a of the rocker shaft 130. Furthermore, the tip of the locking pin 132a is inserted into the long hole 128g of the slider gear 128 (see FIG. 3).

  Then, the locking pin 132a of the control shaft 132 moves in the axial direction through the axially long hole 130a formed in the rocker shaft 130, so that the slider gear 128 can move in the axial direction. Further, since the slider gear 128 itself is locked to the locking pin 132a by the long hole 128g in the circumferential direction, the position in the axial direction is determined by the locking pin 132a, but it swings around the axis. It is possible.

  In a state where the slider gear 128 is disposed in the internal space constituted by the input portion 122 and the swing cams 124 and 126, the input helical spline 128a of the slider gear 128 is engaged with the helical spline 122b of the input portion 122. . The first output helical spline 128 c is engaged with the helical spline 124 b of the first swing cam 124, and the second output helical spline 128 e is engaged with the helical spline 126 b of the second swing cam 126.

  The input portion 122 and the swing cams 124 and 126 are disposed between the standing wall portions 136 and 138 formed integrally with the cylinder head 8 on the bearing portions 124c and 126c side of the swing cams 124 and 126. (See FIG. 2). As shown in FIG. 7A, the fixing portion 140 is attached on the standing wall portions 136 and 138. The fixing portion 140 is formed so that the thickness in the axial direction is thinner than the standing wall portions 136 and 138.

  Further, as shown in FIG. 7 (b), a downward recess 136 a corresponding to the lower part of the center hole of the swing cams 124, 126 is formed at the upper end portions of the standing wall portions 136, 138, and the lower end portion of the fixed portion 140 is An upward recess 140a corresponding to the upper part of the center hole is provided. The rocker shaft 130 is sandwiched and fixed between the standing wall portions 136 and 138 and the fixing portion 140 in a state in which the rocker shaft 130 is fitted in the space formed by both the concave portions 136a and 140a. Therefore, the rocker shaft 130 is fixed to the cylinder head 8 and does not move or rotate in the axial direction.

  As shown in FIG. 7A, the bearing portion 124c of the first swing cam 124 and the standing wall portion 136 facing the bearing portion 124c, and the bearing portion 126c of the second swing cam 126 and the standing wall facing the same. One shim plate 141 is inserted between each portion 138. The shim plate 141 has an inverted U shape when viewed from the side, and is disposed so as to straddle the rocker shaft 130 at the recessed portion (see FIG. 7B). The shim plate 141 is disposed in a state where one side surface (outer side surface) thereof is in contact with the standing wall portions 136 and 138 and the other side surface (inner side surface) is in contact with the bearing portions 124c and 126c. The A gap 142 is provided between the upper portion of the outer surface of the shim plate 141 and the fixing portion 140 facing the shim plate 141. By providing the gap 142, the shim plate 141 is configured such that the outer surface thereof is separated from the fixed portion 140.

  Further, a fitting recess 141 a is provided at the upper end of the shim plate 141. A distal end of a substantially T-shaped fixing plate 143 that fixes the base end to the upper end of the fixing portion 140 is fitted in the fitting recess 141a (see FIG. 7C). In this way, the shim plate 141 is fixed to each fixing portion 140. The first rocking cam 124 and the second rocking cam 126 come into contact with the inner surface of the shim plate 141 on the bearing portions 124c and 126c, respectively, so that the intermediate drive mechanism 120 is illustrated in the left and right directions along the axial direction. Movement to the side is prevented (see FIG. 2). The shim plate 141 includes a plurality of types having different thicknesses with a certain gap difference (for example, 20 μm).

  Further, the control shaft 132 disposed in the rocker shaft 130 is slidably inserted in the rocker shaft 130 in the axial direction, and is connected to the lift amount variable actuator 100 at one end side (see FIG. 2). . The axial displacement of the control shaft 132 can be adjusted by the movement of a piston (not shown) constituting the variable lift amount actuator 100.

  By adjusting the piston position of the lift amount variable actuator 100 with the above-described configuration, the control shaft 132 moves in the axial direction and the axial position of the slider gear 128 changes. Thus, the rotational phase difference between the input unit 122 and the swing cams 124 and 126 can be adjusted. Therefore, by driving the lift amount variable actuator 100, the valve lift amounts of the intake valves 12a and 12b can be continuously adjusted between the maximum valve lift amount and the minimum valve lift amount as shown in FIGS. .

  Here, FIG. 8 shows a state of the intermediate drive mechanism 120 in a state where the piston of the variable lift amount actuator 100 is moved in the F direction (see FIG. 3). In this state, FIG. 8A shows the valve closing time, and FIG. 8B shows the valve opening time. In this case, the rotational phase difference between the roller 122f of the input unit 122 and the noses 124d and 126d of the swing cams 124 and 126 is maximized. For this reason, when the intake cam 45a pushes down the roller 122f of the input part 122 to the maximum extent, the push-down amount of the rocker roller 52a by the cam surfaces 124e and 126e of the noses 124d and 126d becomes maximum, and the valve lift of the intake valves 12a and 12b. The amount is maximum. Accordingly, the amount of intake air from the intake port 14 is also maximized.

  On the other hand, FIG. 9 shows a state of the intermediate drive mechanism 120 in a state where the piston of the variable lift amount actuator 100 is moved most in the R direction (see FIG. 3). In this state, FIG. 9A shows the valve closing time, and FIG. 9B shows the valve opening time. In this case, the rotational phase difference between the roller 122f of the input unit 122 and the noses 124d and 126d of the swing cams 124 and 126 is minimized. For this reason, even if the intake cam 45a pushes down the roller 122f of the input portion 122 to the maximum extent, the push-down amount of the rocker roller 52a by the cam surfaces 124e and 126e of the noses 124d and 126d becomes the minimum, and the valve lift of the intake valves 12a and 12b The amount is minimal. Accordingly, the amount of intake air from the intake port 14 is also minimized.

  As shown in FIG. 2, the rotational phase difference variable actuator 104 is disposed at a position where the rotational force of the crankshaft 144 is transmitted to the intake camshaft 45, and changes the rotational phase difference of the intake camshaft 45 relative to the crankshaft 144. It is something that can be done.

  When the intermediate drive mechanism 120 is assembled to the cylinder head 8, the input portion 122 and the two swing cams 124 and 126 are first attached to the outer periphery of each slider gear 128 fixed to the rocker shaft 130, respectively. At this time, with respect to all the intermediary drive mechanisms 120, the input portion 122 and both swings with respect to the slider gear 128 so that the relative positions of the noses 124d and 126d of the swing cams 124 and 126 with respect to the roller 122f of the input portion 122 are unified. The cams 124 and 126 are aligned. The rocker shaft 130 is sandwiched and fixed between the standing wall portions 136 and 138 and the respective fixing portions 140, and the input portion 122 and the swing cams 124 and 126 are disposed between the standing wall portions 136 and 138, thereby intermediating. The drive mechanism 120 is assembled to the cylinder head 8.

  After the intermediary drive mechanism 120 is assembled to the cylinder head 8 in this way, the positions of the input portion 122 and the swing cams 124 and 126 with respect to the control shaft 132 (slider gear 128) are adjusted over the entire intermediary drive mechanism 120. . That is, as shown in FIG. 10B, the relative positions of the noses 124d and 126d of the swing cams 124 and 126 with respect to the roller 122f of the input unit 122 are aligned.

  When the position adjustment is performed, first, as shown in FIG. 10A, in all the intermediary drive mechanisms 120, the position between the bearing portion 124 c of the first rocking cam 124 and the standing wall portion 136 from above each fixed portion 140. , And a shim plate 141 of any thickness is inserted between the bearing portion 126c of the second swing cam 126 and the standing wall portion 138, respectively. In this state, the input portion 122 and the swing cams 124 and 126 are integrated in the axial direction with the standing wall portions 136 and 138 as a reference by the contact between the outer surface of the shim plate 141 and the standing wall portions 136 and 138. Moving. Then, the input part 122 and the swing cams 124 and 126 have their tips (rollers 122f, noses 124d and 126d) in a predetermined direction via a spline mechanism constituted by the respective inner peripheral surfaces and the outer peripheral surface of the slider gear 128. To turn. Accordingly, the input portion 122 and the swing cams 124 and 126 are aligned with respect to the control shaft 132 (slider gear 128) with reference to the one intermediate drive mechanism 120. As a result, the relative positions of the noses 124d and 126d of the swing cams 124 and 126 with respect to the roller 122f of the input unit 122 are unified over the entire intermediary drive mechanism 120.

The effects obtained by the embodiment described above will be described below.
-Since the gap 142 is provided between the shim plate 141 and the fixing portion 140, the shim plate 141 is disposed away from the fixing portion 140. That is, in the present embodiment, the shim plate 141 is abutted and supported by the standing wall portions 136 and 138 without receiving interference from the fixing portion 140. For this reason, the shim plate 141 is not disposed in a state of being displaced with the complicated mounting state of the fixing portion 140. As a result, the proper position adjustment of the input portion 122 and the swing cams 124 and 126 with respect to the control shaft 132 can be easily performed with the standing wall portions 136 and 138 as a reference.

  In a state where the fixing portion 140 is attached to the standing wall portions 136 and 138, the fixing portion 140 is formed so that the thickness in the axial direction is thinner than that of the standing wall portions 136 and 138. For this reason, it is possible to easily form the gap 142 that contributes to preventing the interference of the fixing portion 140 with the shim plate 141.

In addition, this embodiment can also be changed and embodied as follows.
-Although the fixing | fixed part 140 of this embodiment is formed so that the thickness in the said axial direction may become thin compared with the said standing wall part 136,138, you may make it form both in the same thickness. In this case, a configuration in which the thickness of the upper portion of the shim plate 141 disposed to face the fixed portion 140 is thinner than the thickness of the lower portion of the shim plate 141 is preferable. In such a configuration, a gap similar to the above is provided between the fixing portion 140 and the shim plate 141, and interference between the fixing portion 140 and the shim plate 141 is reduced.

  The shim plate 141 is inserted between either the first swing cam 124 and the standing wall portion 136 or between the second swing cam 126 and the standing wall portion 138, and the input portion 122 for the slider gear 128 and The swing cams 124 and 126 may be aligned.

In the above embodiment, a plurality of shim plates 141 having different thicknesses with a gap difference of 20 μm are provided. However, the gap differences may be appropriately changed to 10 μm, 30 μm, 40 μm, and the like.
The present invention can also be applied to an engine having one or three or more engine valves (intake valves or exhaust valves) of the same type per cylinder. In this case, the number of oscillating cams is changed according to the number of engine valves and becomes one or three or more.

  The variable valve mechanism of the present invention may be applied to the exhaust camshaft 46 to change the maximum lift amount of the exhaust valves 16a and 16b. The variable valve mechanism may be applied to both the intake camshaft 45 and the exhaust camshaft 46 to change the maximum lift amounts of both the intake valves 12a and 12b and the exhaust valves 16a and 16b.

  The rocker shaft 130 may be omitted, and the control shaft 34 may also function as the rocker shaft 130.

The longitudinal section of the engine in one embodiment of the present invention. The schematic plan view which shows the arrangement | positioning relationship of the camshaft and variable valve mechanism in the cylinder head of this embodiment. The partially broken perspective view which shows the internal structure of the mediation drive mechanism of this embodiment. The perspective view which shows the input part of the same mediation drive mechanism. The perspective view which shows the 1st rocking | fluctuation cam of the intermediary drive mechanism. The perspective view which shows the combined state of the said rocker shaft and the said control shaft. (A) is a side view showing the mediation drive mechanism, (b) is a side sectional view taken along line 7b-7b of FIG. 7 (a), and (c) is a plan view showing the mediation drive mechanism. Operation | movement explanatory drawing which shows the variable valve mechanism of this embodiment. Operation | movement explanatory drawing which shows the variable valve mechanism of this embodiment. (A) is a side view which shows the mediation drive mechanism before position adjustment, (b) is a side view which shows the mediation drive mechanism after position adjustment. (A) is a schematic plan view which shows the arrangement | positioning relationship of the conventional variable valve mechanism, (b) is a side view which shows the conventional mediation drive mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Engine as an internal combustion engine, 8 ... Cylinder head, 12a, 12b ... Intake valve, 16a, 16b ... Exhaust valve, 45 ... Intake camshaft, 46 ... Exhaust camshaft, 122 ... Input part, 132 ... Control shaft, 136 138: Standing wall portion 140: Fixed portion 141 ... Shim plate 142 ... Gap.

Claims (2)

In a cylinder head of an internal combustion engine, an input unit driven by a valve driving force from a cam side, an output unit outputting a valve driving force transmitted from the input unit to the valve side, and coaxial with the input unit and the output unit A variable valve mechanism for an internal combustion engine that adjusts a valve characteristic by changing a rotational phase difference between the input unit and the output unit by axial movement of the control shaft.
The control shaft is supported by an upright wall portion integrally formed with the cylinder head and a fixed portion attached on the upright wall portion, and the input portion or the output portion is positioned adjacent to the upright wall portion and the fixed portion. And a shim plate is inserted between the input part or the output part and the standing wall part,
The shim plate is configured to align the input portion and the output portion with respect to the control shaft, and a gap is formed between the shim plate and the fixed portion. Variable valve mechanism of the engine. 2. The variable valve mechanism for an internal combustion engine according to claim 1, wherein the fixed portion is formed so that a thickness in the axial direction of the control shaft is thinner than that of the standing wall portion.

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