JP2011231742A - Variable valve gear for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the drive loss of a rocking cam and to attain miniaturization in a variable valve gear for an internal combustion engine.SOLUTION: Power transmission mechanisms (27A, 27B) are formed from planetary gear mechanisms (32A, 32B) having sun gears (28A, 28B), ring gears (29A, 29B), pinion gears (30A, 30B) and carriers (31A, 31B). A control shaft (21) is connected to the sun gears (28A, 28B), a cam follower (33) is connected to the carriers (31A, 31B) to be in contact with a drive cam (17) of a camshaft (16) to rotate the carriers (31A, 31B), the ring gears (29A, 29B) are formed in an inner periphery of base circular parts (25A, 25B) of rocking cams (24A, 24B) and the rocking cams (24A, 24B) are supported to be freely rocked on the control shaft (21) by the planetary gear mechanisms (32A, 32B).

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine, and more particularly to a variable valve operating apparatus for an internal combustion engine that changes a valve lift amount and a working angle.

  In an internal combustion engine of a vehicle, a swing cam is disposed on the side of a camshaft that rotates in synchronization with a crankshaft, and the swing cam is driven by a driving force transmitted from a drive cam provided on the camshaft through a power transmission mechanism. Some of them are provided with a variable valve device that changes the lift amount of the valve by changing the swing start position of the swing cam in accordance with the rotation of the control shaft.

Japanese Patent Laid-Open No. 10-280931

  In the valve operating apparatus for an internal combustion engine according to Patent Document 1, a swing cam is provided on a cam shaft to which a cam (drive cam) is fixed, and the swing range of the swing cam is changed by the rotation of the control shaft. Thus, the valve lift amount is changed.

However, conventionally, in the valve operating apparatus for an internal combustion engine according to Patent Document 1, the driving cam that receives the reaction force of the valve spring is directly supported by the outer peripheral surface of the camshaft, so that the driving loss due to friction increases. There was an inconvenience of doing.
In addition, power is transmitted from the camshaft cam (drive cam) that rotates with the crankshaft to the swing cam, and when the valve lift is changed, the power is transmitted to the swing cam. There was an inconvenience that the mechanism became large.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine that reduces the drive loss of a swing cam and is downsized.

According to the present invention, a swing cam is disposed on the side of a cam shaft that rotates in synchronization with a crankshaft, and the swing cam is driven by a driving force transmitted from a drive cam provided on the cam shaft via a power transmission mechanism. In the variable valve operating apparatus for an internal combustion engine, which changes the lift amount of the valve by changing the swing start position of the swing cam as the control shaft rotates while swinging the valve to lift the valve. The mechanism is constituted by a planetary gear mechanism having a sun gear, a ring gear arranged outside the sun gear, a pinion gear meshing with the sun gear and the ring gear, and a carrier that holds the pinion gear so that it can revolve with respect to the sun gear. The control shaft is connected to the sun gear, the cam follower that rotates the carrier in contact with the drive cam is connected to the carrier, Forming a Gugiya the inner peripheral portion of the base circle portion of the swing cam,
The swing cam is swingably supported on the control shaft by the planetary gear mechanism.

  According to the present invention, since the swing cam is not directly provided on the control shaft or the sliding portion of the cam shaft, the drive loss of the swing cam can be reduced and the size can be reduced.

FIG. 1 is a perspective view of a variable valve operating apparatus for an internal combustion engine. (Example) FIG. 2 is a front view of the variable valve operating apparatus for the internal combustion engine. (Example) FIG. 3 is a sectional view of the swing cam and the power transmission mechanism. (Example) FIG. 4 is an exploded view of a variable valve operating apparatus for an internal combustion engine. (Example) FIG. 5 is an exploded view of the one-side power transmission mechanism of FIG. (Example) FIG. 6 is an exploded view of the other power transmission mechanism of FIG. (Example) FIG. 7 is an assembly diagram of the power transmission mechanism when the internal combustion engine has four cylinders. (Example) FIG. 8A is a front view showing an operation when the valve is slightly lifted and not lifted. FIG. 8B is a front view showing an operation at the time of lift when the valve is slightly lifted. (Example) FIG. 9 (A) is a front view showing the operation when the valve is lifted largely and is not lifted. FIG. 9B is a front view showing the operation at the time of lift when the valve is lifted greatly. (Example)

  An object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine in which a valve is lifted by a swing cam and a valve lift characteristic is changed. Is not provided directly on the sliding portion of the control shaft or cam shaft.

1 to 9 show an embodiment of the present invention.
1 and 2, reference numeral 1 denotes a multi-cylinder (four-cylinder) internal combustion engine mounted on a vehicle, and 2 denotes a cylinder head of the internal combustion engine 1. Hereinafter, the crank axis direction of the internal combustion engine 1 will be referred to as the front-rear direction, the cylinder axis direction will be referred to as the vertical direction, and the direction orthogonal to the crank axis and the cylinder center line will be described as the left-right direction.
As shown in FIGS. 1 and 2, the internal combustion engine 1 includes an intake valve or an exhaust valve that opens and closes a port including an intake port or an exhaust port that communicates with a combustion chamber of the cylinder head 2. As the two valves, a one-side valve 3A arranged at the front and an other-side valve 3B arranged behind the one-side valve 3A are provided. As shown in FIG. 2, the one side valve 3 </ b> A and the other side valve 3 </ b> B are supported by the cylinder head 2 so as to be reciprocally movable in the vertical direction with an axis inclined at a predetermined angle when viewed from the front.
The one-side valve 3A is composed of a one-side valve head 4A at the front end portion that is in contact with and away from the opening of the port, and a one-side valve stem 5A that is connected to the one-side valve head 4A. A one-side valve retainer 6A is attached to the upper end of the one-side valve stem 5A, and a one-side valve spring 7A is attached.
The other-side valve 3B is composed of the other-side valve head 4B at the distal end that is brought into contact with and away from the opening of the port, and the other-side valve stem 5B that is connected to the other-side valve head 4B. The other side valve stem 5B is attached with the other side valve retainer 6B at the upper end, and is fitted with the other side valve spring 7B.

In the internal combustion engine 1, the one side rocker arm 8 </ b> A that opens and closes the one side valve 3 </ b> A in the axial direction (vertical direction) and the other side valve 3 </ b> B moves in the axial direction (vertical direction) to open and close the valve. The other side rocker arm 8B is provided.
The one-side rocker arm 8A is rotatably provided on a one-side arm portion 9A that is disposed horizontally and horizontally, and on a one-side roller pin 10A that is supported on the central portion of the one-side arm portion 9A. The side rocker roller 11A, a one-side valve contact portion 12A formed at the right end portion of the one-side arm portion 9A, and a one-side support portion 13A formed at the left end portion of the one-side arm portion 9A are provided.
The other side rocker arm 8B is provided on the other side arm portion 9B that is horizontally and horizontally oriented, and the other side roller pin 10B that is rotatably supported by the central portion of the other side arm portion 9B. The side rocker roller 11B, the other side valve contact portion 12B formed at the right end portion of the other side arm portion 9B, and the other side support portion 13B formed at the left end portion of the other side arm portion 9B are provided.
One side rocker shaft hole 14A oriented in the front-rear direction is formed in one side support portion 13A. The other side rocker shaft hole 14B oriented in the front-rear direction is formed in the other side support portion 13B. Both ends of the rocker shaft 15 that supports the one side rocker arm 8A and the other side rocker arm 8B so as to be swingable are inserted into the one side rocker shaft hole 14A and the other side rocker shaft hole 14B.

  A camshaft 16 that rotates in synchronization with the crankshaft of the internal combustion engine 1 and operates the one side valve 3A and the other side valve 3B is supported on the cylinder head 2 of the internal combustion engine 1 so as to be directed in the front-rear direction. A driving cam 17 is integrally provided on the cam shaft 16. The drive cam 17 includes a base circle portion 18 and a lift curve portion 19 protruding from the base circle portion 18 in the radial direction.

The internal combustion engine 1 is provided with a variable valve gear 20 that changes the lift characteristics of the one-side valve 3A and the other-side valve 3B.
As shown in FIGS. 1, 2, and 4, the variable valve gear 20 is disposed between the one-side valve 3 </ b> A / other-side valve 3 </ b> B and the cam shaft 16 in parallel with the cam shaft 16 in the front-rear direction. The control shaft 21 is provided. As shown in FIG. 7, the rotation of the control shaft 21 is controlled by an actuator 22 made of an electric motor or the like. The actuator 22 is driven and controlled by the control means 23.
The control shaft 21 is disposed on the side of the cam shaft 16 so as to lift the one side valve 3A and the other side valve 3B supported by the control shaft 21 so as to be swingable, and corresponds to the one side rocker arm 8A. Thus, a one-side swing cam 24A disposed in front and an other-side swing cam 24B disposed in rear corresponding to the other-side rocker arm 8B are provided. Therefore, in the variable valve operating apparatus 20, two one-side swing cams 24A and the other-side swing cam 24B are provided for one cylinder.
The one-side swing cam 24A includes a one-side base circle 25A that does not lift the one-side valve 3A, and a one-side lift curve portion 26A that protrudes radially from the one-side base circle 25A and lifts the one-side valve 3A. It has.
The other-side swing cam 24B includes an other-side base circle 25B that does not lift the other-side valve 3B, and an other-side lift curve portion 26B that protrudes radially from the other-side base circle 25B and lifts the other-side valve 3B. It has.

  As shown in FIG. 4, the variable valve operating apparatus 20 includes a one-side swing cam 24 </ b> A · The other-side swing cam 24B is swung to lift the one-side valve 3A and the other-side valve 3B, while the one-side swing cam 24A and the other-side swing cam 24B start swinging as the control shaft 21 rotates. The valve lift amount of the one side valve 3A and the other side valve 3B is changed by changing the position.

As shown in FIG. 5, the one-side power transmission mechanism 27A meshes with the one-side sun gear 28A, the one-side ring gear 29A arranged outside the one-side sun gear 28A, the one-side sun gear 28A, and the one-side ring gear 29A. The three one-side pinion gears 30A, 30A, 30A arranged in a triangular shape at equal intervals in the circumferential direction, and the one-side pinion gears 30A, 30A, 30A are held so as to be able to revolve with respect to the one-side sun gear 28A. It comprises a one-side planetary gear mechanism 32A having a side carrier 31A. In this case, the one-side sun gear 28 </ b> A is provided on the control shaft 21 at a position corresponding to the one-side swing cam 24 </ b> A, and is connected to the control shaft 21. A cam follower 33 that contacts the drive cam 17 of the cam shaft 16 and rotates the one-side carrier 31A is connected to the one-side carrier 31A. The one-side ring gear 29A is formed on the inner peripheral portion of the one-side base circle 25A of the one-side swing cam 24A.
As a result, the one-side swing cam 24A is swingably supported on the control shaft 21 by the one-side planetary gear mechanism 32A. In this case, as the control shaft 21 rotates, the one-side swing cam 24A rotates via the one-side pinion gears 30A, 30A, and 30A to change the phase.
Further, as shown in FIG. 6, the other-side power transmission mechanism 27B is connected to the other-side sun gear 28B, the other-side ring gear 29B arranged outside the other-side sun gear 28B, the other-side sun gear 28B, and the other-side ring gear 29B. Three other-side pinion gears 30B, 30B, and 30B arranged in a triangular shape at equal intervals in the circumferential direction so as to mesh with each other and the other-side pinion gears 30B, 30B, and 30B are held so as to revolve with respect to the other-side sun gear 28B. The other-side planetary gear mechanism 32B having the other-side carrier 31B. In this case, the other-side sun gear 28B is provided on the control shaft 21 at a position corresponding to the other-side swing cam 24B, and is connected to the control shaft 21. The other carrier 31B is connected to a cam follower 33 that contacts the drive cam 17 of the cam shaft 16 and rotates the other carrier 31B. The other side ring gear 29B is formed on the inner periphery of the other side base circle 25B of the other side swing cam 24B.
Thus, the other-side swing cam 24B is swingably supported on the control shaft 21 by the other-side planetary gear mechanism 32B.

With such a structure, the one-side swing cam 24A and the other-side swing cam 24B that receive the reaction force of the one-side valve spring 7A and the other-side valve spring 7B during the valve lift are used as the one-side planetary gear mechanism 32A and the other-side planetary gear. Since the gear mechanism 32B is swingably supported on the control shaft 21, the drive loss due to friction is reduced as compared with the case where the one-side swing cam 24A and the other-side swing cam 24B are directly supported on the outer peripheral surface of the control shaft 21. Can be reduced.
Further, the control shaft 21 is connected to the one-side sun gear 28A and the other-side sun gear 28B, and the one-side carrier 31A and the other-side carrier 31B are brought into contact with the driving cam 17 of the camshaft 16 with the one-side carrier 31A and the other-side carrier 31B. Connected to the rotating cam follower 33, the one-side ring gear 29A and the other-side ring gear 29B are connected to the inner peripheral portions of the one-side base circular portion 25A and the other-side base circular portion 25B of the one-side swing cam 24A and the other-side swing cam 24B. Because of this, when changing the valve lift amount, all the parts that transmit the rotation of the control shaft 21 to the one-side swing cam 24A and the other-side swing cam 24B are all of the one-side swing cam 24A and the other-side swing cam 24B. The variable valve device 20 can be reduced in size because it can be housed inside.
Further, as shown in FIG. 7, even when the internal combustion engine 1 has four cylinders, the gears constituting the one-side planetary gear mechanism 32A and the other-side planetary gear mechanism 32B are arranged on one side for each cylinder. Since the one-side oscillating cam 24A and the other-side oscillating cam 24B can be assembled from the end of the control shaft 21 in a state assembled in advance to the oscillating cam 24A and the other-side oscillating cam 24B. The productivity of 20 can be improved.

Further, as described above, two one-side valves 3A, other-side valves 3A, one-side swing cams 24A, and other-side swing cams 24B are provided for one cylinder.
As shown in FIG. 5, the one-side carrier 31A sandwiches the one-side swing cam 24A from opposite directions and is integrated with the one-side pinion gears 30A, 30A, 30A via the one-side rotating shafts 34A, 34A, 34A. A pair of connected one side thrust plates, that is, a front side one thrust plate 35A and a rear side one thrust plate 35A are provided. The one-side rotation shafts 34A, 34A, 34A of the one-side pinion gears 30A, 30A, 30A have front shaft holes 36A, 36A, 36A in the front one-side thrust plate 35A and rear shaft holes 36A in the rear one-side thrust plate 35A. It is inserted into 36A and 36A, and its axis is supported in parallel with the cam shaft 16.
As shown in FIG. 6, the other-side carrier 31B sandwiches the other-side swing cam 24B from the direction facing each other and is integrated with the other-side pinion gears 30B, 30B, and 30B via the other-side rotation shafts 34B, 34B, and 34B. A pair of other thrust plates to be connected, that is, a front other thrust plate 35B and a rear other thrust plate 35B are provided. The other side rotation shafts 34B, 34B, 34B of the other side pinion gears 30B, 30B, 30B are arranged in the front shaft holes 36B, 36B, 36B of the front side other thrust plate 35B and the rear side shaft hole 36B of the rear side other thrust plate 35B. It is inserted into 36B and 36B, and its axis is supported in parallel with the cam shaft 16.
Of the one side thrust plate 35A and the other side thrust plate 35B, as the two thrust plates disposed on the cylinder center side, the rear one side thrust plate 35A and the front other side thrust plate 35B are cam followers 33. Connected by
One drive cam 17 of the cam shaft 16 is disposed at a position facing the cam follower 33 of the cam shaft 16.

  With this structure, two drive cams 17 and the cam follower 33 are reduced by one because the drive cam 17 can swing the two swing cams 24A and the other swing cam 24B at the same time. Thus, it is possible to reduce drive loss due to friction between the drive cam 17 and the cam follower 33, and to reduce the number of parts, thereby reducing the size of the variable valve operating apparatus 20.

Further, the one-side swing cam 24A and the other-side swing cam 24B are the base of the drive cam 17 by the rear one-side thrust plate 35A and the front other-side thrust plate 35B, which are two thrust plates connected by the cam follower 38. Positioning is performed in the axial direction of the control shaft 21 with the circular portion 18 in between.
With such a structure, parts (thrust position regulating parts) for positioning the one-side rocking cam 24A and the other-side rocking cam 24B in the axial direction of the control shaft 21 can be reduced, and the variable valve gear 20 can be downsized. be able to.

Further, as shown in FIG. 4, the cam follower 33 includes a pin 37 that connects the rear one-side thrust plate 35 </ b> A and the other front thrust plate 35 </ b> B, and a roller 38 that is rotatably held on the outer periphery of the pin 37. With. The pin 37 has a radial direction centering on the axis of the control shaft 21 and is located closer to the inner circumference than the one-side base circular portion 25A and the other-side base circular portion 25B of the one-side swing cam 24A and the other-side swing cam 24B. Further, it is inserted into the one side roller pin hole 39A of the rear one side thrust plate 35A and the other side roller pin hole 39B of the front side other thrust plate 35B, and its axis is supported in parallel with the cam shaft 16.
With such a structure, it is possible to reduce the size of the variable valve apparatus 20 by reducing the size of the cam follower 33 in the radial direction.

In addition, the rear one-side thrust plate 35A and the front other-side thrust plate 35B, which are two thrust plates connected by the cam follower 33, are the one-side base circular portion of the one-side swing cam 24A and the other-side swing cam 24B. 25A and connected by a return spring pin 40 on the inner peripheral side of the other side base circle 25B. The return spring pin 40 is inserted into the one side spring pin hole 41A of the rear side one thrust plate 35A and the other side spring pin hole 41B of the front side thrust plate 35B, and its axis is parallel to the cam shaft 16. Supported.
The cam follower 33 has a return spring 42 that rotates the one-side swing cam 24A and the other-side swing cam 24B so that the cam-follower 33 is always in contact with the drive cam 17. Most of the cam followers 33 are the one-side swing cam 24A and the other-side swing cam 24B. It arrange | positions so that it may enter into the inner peripheral part of 25 A of 1 side base circle parts, and the other side base circle part 25B. As shown in FIGS. 2 and 4, the lower end of the return spring 42 is supported by the surface of the cylinder head 2, and the upper end is supported by the return spring pin 40 via the tappet 43.
With such a structure, most of the return spring 42 can be disposed on the inner peripheral portion of the one side base circular portion 25A and the other side base circular portion 25B of the one side swing cam 24A and the other side swing cam 24B. The valve device 20 can be downsized.
As shown in FIG. 3, the one-side roller pin hole 39A / other-side roller pin hole 39B and the one-side spring pin hole 41A / other-side spring pin hole 41B include the one-side shaft hole 36A / other-side located at the upper part. They are arranged substantially symmetrically on the left and right with respect to the shaft hole 36B.

Further, as shown in FIGS. 4 to 6, the one-side thrust plate 35A and the other-side thrust plate 35B are gears disposed on the outer periphery of the one-side swing cam 24A and the other-side swing cam 24B. One side cutout portion 44A and the other side cutout portion 44B that can supply oil are provided.
With such a structure, the oil scattered in the valve chamber in the upper part of the cylinder head 2 of the internal combustion engine 1 is transferred from the one side cutout portion 44A and the other side cutout portion 44B to the one side swing cam 24A and the other side swing cam 24B. It can be supplied to the gears arranged on the inner peripheral portion, and the lubrication structure of the gears can be simplified and the variable valve operating device 20 can be miniaturized.

Furthermore, as shown in FIGS. 4 to 6, the one-side thrust plate 35 </ b> A / other-side thrust plate 35 </ b> B includes a one-side through hole 45 </ b> A / other-side through hole 45 </ b> B through which the control shaft 21 penetrates at the center. . The diameter D1 of the one side through hole 45A and the other side through hole 45B is set larger than the outer diameter D2 of the one side sun gear 28A and the other side sun gear 28B.
With such a structure, as shown in FIG. 3, with the one-side sun gear 28A and the other-side sun gear 28B fixed to the control shaft 21, the control shaft 21 is connected to the one-side swing cam 24A and the other-side swing cam 24B. Therefore, the manufacturability of the variable valve operating apparatus 20 can be improved.

Next, the operation at the time of lifting of the variable valve apparatus 20 will be described with reference to FIGS.
FIG. 8 shows a case where the one side valve 3A and the other side valve 3B are slightly lifted.
FIG. 8A shows a case where the one-side valve 3A and the other-side valve 3B are slightly lifted and not lifted. The base circular portion 18 of the drive cam 17 is in contact with the roller 38 and the one-side swing cam. The one side base circle 25A and the other side base circle 25B apart from the one side lift curve portion 26A and the other side lift curve portion 26B of 24A and the other side swing cam 24B are in contact with the one side rocker roller 11A and the other side rocker roller 11B. The one side valve 3A and the other side valve 3B are not lifted.
FIG. 8B shows a case where the one-side valve 3A and the other-side valve 3B are lifted slightly, and the lift is shown. The lift curve portion 19 of the drive cam 17 is in contact with the roller 38 and the one-side swing cam 24A. The one side lift curve portion 26A of the other side swing cam 24B, the one side base circle portion 25A of the other side lift curve portion 26B, and the portion close to the other side base circle portion 25B are in contact with the one side rocker roller 11A and the other side rocker roller 11B. The one side valve 3A and the other side valve 3B are slightly lifted.

On the other hand, FIG. 9 shows a case where the one side valve 3A and the other side valve 3B are lifted greatly.
FIG. 9A shows a case where the one-side valve 3A and the other-side valve 3B are largely lifted and when not lifted. The base circular portion 18 of the drive cam 17 is in contact with the roller 38 and the one-side swing cam. A portion close to the one side lift curve portion 26A and the other side lift curve portion 26B of the other side swing cam 24B is in contact with the one side rocker roller 11A and the other side rocker roller 11B, and the one side valve 3A and the other side valve 3B are Not lifted.
FIG. 9B shows a case where the one-side valve 3A and the other-side valve 3B are largely lifted. The lift curve portion 19 of the drive cam 17 is in contact with the roller 38 and the one-side swing cam 24A. The tip portion of the one side lift curve portion 26A and the other side lift curve portion 26B of the other side swing cam 24B is in contact with the one side rocker roller 11A and the other side rocker roller 11B, and the one side valve 3A and the other side valve 3B are large. Lifting.

That is, in this embodiment, the one-side rocking cam 24A and the other-side rocking cam 24B are connected via the one-side pinion gear 30A and the other-side pinion gear 30B by the one-side sun gear 28A and the other-side sun gear 28B provided on the control shaft 21. The lift amount and the operating angle of the one side valve 3A and the other side valve 3B are changed by changing the swing phase of the one side swing cam 24A and the other side swing cam 24B. For this reason, the one-side rocking cam 24A and the other-side rocking cam 24B that receive the reaction force of the one-side valve spring 7A and the other-side valve spring 7A do not have a sliding movement with respect to the control shaft 21, and friction is generated. Can be reduced.
Further, the gears constituting the one-side planetary gear mechanism 32A and the other-side planetary gear mechanism 32B can be assembled to the control shaft 21 in advance in the one-side oscillating cam 24A and the other-side oscillating cam 24B. The assembling property of the variable valve device 20 can be improved.
Further, the base circle portion 18 of the cam shaft 16 can be assembled to the cylinder head 2 with the one side thrust plate 35A and the other side thrust plate 35B overlapping in the radial direction, and the one side swinging cam 24A and the other side swinging. It is not necessary to add another part for restricting the thrust direction of the cam 24B.

  The variable valve operating apparatus according to the present invention can be applied to internal combustion engines of various vehicles.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder head 3A One side valve 3B Other side valve 7A One side valve spring 7B Other side valve spring 8A One side rocker arm 8B Other side rocker arm 16 Cam shaft 17 Drive cam 20 Variable valve device 21 Control shaft 24A One side swing Moving cam 24B Other side swing cam 27A One side power transmission mechanism 27B Other side power transmission mechanism 28A One side sun gear 28B Other side sun gear 29A One side ring gear 29B Other side ring gear 30A One side pinion gear 30B Other side pinion gear 31A One side carrier 31B etc. Side carrier 32A One side planetary gear mechanism 32B Other side planetary gear mechanism 33 Cam follower 35A One side thrust plate 35B Other side thrust plate 37 Pin 38 Roller 40 Return spring pin 42 Return spring 44A One side notch 4B the other side cutout portion 45A one side through-hole 45B other side through hole

Claims (7)

  A swing cam is disposed on the side of a camshaft that rotates in synchronization with the crankshaft, and the swing cam is swung by a driving force transmitted from a drive cam provided on the camshaft through a power transmission mechanism. In the variable valve operating apparatus for an internal combustion engine that lifts the valve and changes the lift amount of the valve by changing the swing start position of the swing cam as the control shaft rotates, the power transmission mechanism includes a sun gear. And a planetary gear mechanism having a ring gear disposed outside the sun gear, a pinion gear meshing with the sun gear and the ring gear, and a carrier that holds the pinion gear so as to be capable of revolving with respect to the sun gear. The control shaft is connected, a cam follower that rotates the carrier in contact with the drive cam is connected to the carrier, and the ring gear is connected to the front. Formed in the inner peripheral portion of the base circle portion of the oscillating cam, variable valve device for an internal combustion engine, characterized in that the swingably supported on the control shaft the rocking cam by the planetary gear mechanism.   Two valves and two swing cams are provided for one cylinder, and the carrier sandwiches the swing cams from opposite directions and is integrally connected via the rotation shaft of the pinion gear. A pair of thrust plates is provided, two thrust plates arranged on the cylinder center side of the thrust plates are connected by the cam follower, and one drive cam is arranged at a position facing the cam follower of the cam shaft. The variable valve operating apparatus for an internal combustion engine according to claim 1.   3. The internal combustion engine according to claim 2, wherein the swing cam is positioned in the axial direction of the control shaft with a base circle portion of the drive cam sandwiched between two thrust plates connected by the cam follower. Variable valve device.   The cam follower includes a pin that connects the thrust plate and a roller that is rotatably held on an outer periphery of the pin, and the pin is arranged in a radial direction about the axis of the control shaft from a base circle portion of the swing cam. The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein the variable valve operating apparatus is also disposed on the inner peripheral side.   Two thrust plates connected by the cam follower are connected by a return spring pin on the inner peripheral side of the base circle portion of the swing cam, and the swing cam is fixed so that the cam follower is always in contact with the drive cam. 3. The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein a return spring to be rotated is arranged so that most of the return spring enters an inner peripheral portion of a base circle portion of the swing cam.   3. The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein the thrust plate has a notch portion capable of supplying oil to gears disposed on an inner peripheral portion of the swing cam on an outer peripheral portion. .   3. The internal combustion engine according to claim 2, wherein the thrust plate includes a through hole through which the control shaft passes in a central portion, and the diameter of the through hole is set to be larger than the outer diameter of the sun gear. Variable valve device.

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