JP4680215B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve operating apparatus for an internal combustion engine, and more particularly to a valve operating apparatus for an internal combustion engine capable of changing the valve operating characteristics of an engine valve composed of an intake valve or an exhaust valve.

  As an example of a conventional valve operating device for an internal combustion engine, a drive cam that rotates integrally with a cam shaft, a valve cam that is swingably supported by the cam shaft, and that swings by the drive cam. A sub rocker arm that swings the valve cam, a holder that supports the sub rocker arm, is driven by the control mechanism and swings about the cam shaft, and is provided between the holder and the valve cam. And a return spring that constantly urges the engine valve to a position where the engine valve is closed. Then, the return spring is curved in an arc shape in a natural state by being held by a spring holding portion provided at one end of the valve cam and being held at a spring holding portion provided at the holder. (For example, refer to Patent Document 1).

JP 2005-207254 A

  By the way, in the valve operating device of the internal combustion engine described in Patent Document 1, since the return spring that constantly biases the valve operating cam to the position where the engine valve is closed is used in a curved shape, the stress acting on the return spring is used. Became uneven, and stress was concentrated inside the return spring curved in an arc shape. Therefore, it is necessary to enlarge the return spring so as to withstand this stress concentration, leading to an increase in the size of the valve gear.

  The present invention has been made to solve such a problem, and its purpose is to alleviate the stress acting on the return spring, to reduce the return spring, and to reduce the size of the valve operating device. An object of the present invention is to provide a valve operating apparatus for an internal combustion engine.

  In order to achieve the above object, an invention according to claim 1 is provided such that a camshaft rotatably supported by a cylinder head and rotating in synchronization with the rotation of an internal combustion engine, and provided on the camshaft, is integrated with the camshaft. A rotating drive cam, supported by a camshaft so as to be swingable, and a valve drive cam that opens and closes an engine valve. It is supported so as to be swingable around the camshaft, and transmits the valve driving force of the drive cam to the valve drive cam. And a link mechanism for swinging the valve cam, a control mechanism for swinging the link mechanism, and a drive mechanism for driving the control mechanism, and at the swing position of the link mechanism swung by the control mechanism, In a valve operating apparatus for an internal combustion engine that can change a valve operating characteristic that an engine valve opens and closes, a link mechanism is provided between a holder supported so as to be able to swing around a cam shaft, and the valve operating cam. The valve cam is always attached to the position where the engine valve closes. A return spring provided on the holder and holding one end of the return spring, and a cam side spring holding provided on the valve cam and holding the other end of the return spring. And at least one of the holder side spring holding part and the cam side spring holding part hold | maintains the edge part of a return spring rotatably.

  The invention according to claim 2 is characterized in that, in addition to the configuration of the invention according to claim 1, both the holder-side spring holding portion and the cam-side spring holding portion hold both ends of the return spring rotatably. And

  According to a third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the holder-side spring holding portion is fitted to a spring seat support member provided in the holder and a spring seat support member. A spring seat member that slides on the spring seat support member and is provided with a contact surface with the return spring, and the cam-side spring holding portion includes a spring seat support member provided on the valve cam, and a spring A spring seat member that fits with the seat support member, slides on the spring seat support member, and is provided with a contact surface with the return spring, and either the spring seat support member or the spring seat member Is a convex arc shape, and the other is a concave arc shape.

  According to a fourth aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, the holder-side spring holding portion is rotatably supported by the holder via a pin, and is in contact with the return spring. The cam-side spring holding portion has a spring support member that is rotatably supported by a valve operating cam via a pin and is provided with a contact surface with a return spring. To do.

  According to a fifth aspect of the present invention, in addition to the configuration of the first or second aspect, the holder-side spring holding portion is rotatably supported by the holder via a pin and is in contact with the return spring. The cam-side spring holding portion is fitted to the spring seat support member provided on the valve cam and the spring seat support member, and slides on the spring seat support member to return. A spring seat member provided with a contact surface with the spring, wherein one of the spring seat support member and the spring seat member has a convex arc shape and the other has a concave arc shape.

  According to a sixth aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, the holder-side spring holding portion is fitted to a spring seat support member provided on the valve cam, and the spring seat support member And a spring seat member that slides on the spring seat support member and is provided with a contact surface with the return spring, and either the spring seat support member or the spring seat member has a convex arc shape, The cam spring holding portion is rotatably supported by a holder via a pin and has a spring support member provided with a contact surface with a return spring.

  According to a seventh aspect of the invention, in addition to the configuration of the invention according to any of the third to sixth aspects, one of the holder side spring holding portion and the cam side spring holding portion is provided with the other spring holding portion. A spring guide rod that penetrates is provided, and a through hole that guides the axial sliding of the spring guide rod is provided in the other spring holding portion.

  According to an eighth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the contact surface between the holder side spring holding portion and the return spring, the cam side spring holding portion, and the return spring. The holder-side spring holding portion and the cam-side spring holding portion rotate so that the abutting surface is always in parallel with each other.

  According to the valve operating apparatus for an internal combustion engine according to claim 1, the link mechanism is provided between the holder supported so as to be swingable about the cam shaft, and the holder and the valve operating cam. A return spring that constantly urges the engine valve to a position where the engine valve closes, a holder-side spring holding portion that holds one end of the return spring, and a valve cam that holds the other end of the return spring. Cam-side spring holding portion, and at least one of the holder-side spring holding portion and the cam-side spring holding portion rotatably holds the end of the return spring. Therefore, the stress acting on the return spring can be relieved. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size.

  According to the valve operating apparatus for an internal combustion engine according to claim 2, since both the holder-side spring holding portion and the cam-side spring holding portion hold both ends of the return spring in a rotatable manner, Along with this, each spring holding portion rotates with respect to the holder or the valve cam so that the expansion and contraction of the return spring can be maintained in a linear motion, so that the stress acting on the return spring can be relaxed. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size.

  According to the valve operating apparatus for an internal combustion engine according to claim 3, the holder-side spring holding portion is fitted to the spring seat support member provided on the holder and the spring seat support member, and slides on the spring seat support member. And a spring seat member provided with a contact surface with the return spring, and the cam side spring holding portion is fitted with the spring seat support member provided on the valve operating cam and the spring seat support member. A spring seat member that slides on the spring seat support member and is provided with a contact surface with the return spring, and either the spring seat support member or the spring seat member has a convex arc shape, and the other The spring seat member is supported by the spring seat as the valve cam swings to form a concave arc shape. By sliding the Zaijo, it is possible to maintain the expansion and contraction of the return spring to linear motion, it is possible to relieve the stress acting on the return spring. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size. Moreover, since the structure of each spring holding part can be simplified, weight reduction can be achieved.

  According to the valve operating apparatus for an internal combustion engine according to claim 4, the holder-side spring holding portion includes a spring support member that is rotatably supported by the holder via the pin and provided with a contact surface with the return spring. The cam-side spring holding portion is rotatably supported by the valve cam via a pin and has a spring support member provided with a contact surface with the return spring. Since each spring support member rotates with respect to the holder or the valve cam, the expansion and contraction of the return spring can be maintained in a linear motion, so that the stress acting on the return spring can be relieved. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size. Further, since the spring support member is rotatably supported by the holder or the valve cam via the pin, the friction when the spring support member rotates relative to the holder or the valve cam can be kept low.

  According to the valve operating apparatus for an internal combustion engine according to claim 5, the holder-side spring holding portion includes a spring support member that is rotatably supported by the holder via the pin and provided with a contact surface with the return spring. The cam-side spring holding portion is fitted to the spring seat support member provided on the valve cam and the spring seat support member, and slides on the spring seat support member to provide a contact surface with the return spring. A spring seat member, and one of the spring seat support member and the spring seat member has a convex arc shape and the other has a concave arc shape. Rotates with respect to the holder, and the spring seat member slides on the spring seat support member, thereby It is possible to maintain the expansion and contraction of the ring to the linear motion, it is possible to relieve the stress acting on the return spring. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size. Further, since the structure of the valve cam can be simplified, the weight of the valve cam can be reduced.

  According to the valve operating apparatus for an internal combustion engine according to claim 6, the holder-side spring holding portion is fitted to the spring seat support member provided on the valve operating cam and the spring seat support member, and on the spring seat support member. A spring seat member provided with a contact surface with a return spring, and either one of the spring seat support member and the spring seat member has a convex arc shape, and the other has a concave arc shape, Since the cam-side spring holding portion has a spring support member that is rotatably supported by the holder via a pin and is provided with a contact surface with the return spring, the spring seat member is moved along with the swing of the valve cam. The spring seat support member slides and the spring support member rotates with respect to the valve cam so that the return is achieved. It is possible to maintain the expansion and contraction of the pulling into linear motion, it is possible to relieve the stress acting on the return spring. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size. Further, since the spring support member is rotatably supported by the valve cam via the pin, the friction of the swinging valve cam can be kept low.

  According to the valve operating apparatus for an internal combustion engine according to claim 7, a spring guide rod penetrating the other spring holding portion is provided in one of the holder side spring holding portion and the cam side spring holding portion, and the other Since the spring holding portion is provided with a through hole that allows the spring guide rod to pass through and guides its axial sliding, the return spring is guided by the spring guide rod, so that the linear motion of the return spring is easily maintained. be able to.

  According to the valve operating apparatus for an internal combustion engine according to claim 8, the contact surface between the rudder-side spring holding portion and the return spring and the contact surface between the cam-side spring holding portion and the return spring are always parallel. Thus, since the holder-side spring holding portion and the cam-side spring holding portion rotate, the expansion and contraction of the return spring accompanying the swinging of the valve cam can be maintained in a linear motion, so that the stress acting on the return spring is reduced. Can be relaxed. Thereby, since a return spring can be made small, a valve operating apparatus can be reduced in size.

  Embodiments of a valve operating apparatus for an internal combustion engine according to the present invention will be described below in detail with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

(First embodiment)
First, with reference to FIGS. 1-10, 1st Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention is described.
1 is a partially cutaway sectional view of an internal combustion engine to which a first embodiment of a valve operating apparatus for an internal combustion engine according to the present invention is applied, FIG. 2 is a sectional view taken along the line WW in FIG. 1, and FIG. FIG. 4 is an explanatory view of the valve operating device shown in FIG. 1, and FIG. 4A is a view of the link mechanism with a part of the plate removed. FIG. 5B is a sectional view taken along line XX of FIG. 5A, FIG. 5 is an explanatory view of the collar shown in FIG. 2, FIG. 5A is an enlarged plan view near the collar, and FIG. ) Is a cross-sectional view taken along the line Y-Y, FIG. 6 is an explanatory view of the valve gear in a state in which the minimum valve operating characteristic is obtained, (a) is a diagram of the link mechanism before the valve cam is swung, ) Is a diagram of the link mechanism when the valve cam is swung, FIG. 7 is an explanatory diagram of the valve gear in a state where the maximum valve operating characteristic is obtained, and (a) is a link before the valve cam is swung. FIG. 8B is a view of the link mechanism when the valve cam is swung, FIG. 8 is a view of the cylinder head in a state where a part of the head cover is broken, and FIG. FIG. 10 is an explanatory diagram of a modification of the first embodiment, (a) is a diagram of the link mechanism before the valve cam swings, and (b) is the link mechanism when the valve cam swings. FIG.

  The internal combustion engine E of the present embodiment is mounted on a motorcycle, and is an air-cooled single-cylinder four-stroke internal combustion engine as shown in FIGS. 1 and 2, and a crank that rotatably supports a crankshaft. A cylinder 1 coupled to the case, a cylinder head 2 coupled to the upper end portion of the cylinder 1, and a head cover 3 coupled to the upper end portion of the cylinder head 2 are provided.

  In the following description, the vertical direction is the cylinder axis direction, and the axial direction, radial direction, and circumferential direction are the axial direction, radial direction, and circumferential direction of the cam shaft 20, respectively.

  A piston 4 coupled to the crankshaft is fitted to the cylinder 1 so as to be able to reciprocate. The cylinder head 2 is formed with a combustion chamber 5 that faces the piston 4 in the cylinder axial direction, and an intake port 6 and an exhaust port 7 that open to the combustion chamber 5, and a pair of spark plugs 8 facing the combustion chamber 5. It is attached. Further, an intake valve 10 and an exhaust valve 11, which are engine valves that are always urged in a valve closing direction by a valve spring 9, slide on valve guides 13 and 13 that are press-fitted into the cylinder head 2, respectively. Supported as possible.

  In this internal combustion engine E, the mixture of the fuel and the intake air supplied from the intake device to the intake port 6 flows into the combustion chamber 5 when the intake valve 10 is opened and is compressed by the piston 4, and then the spark plug 8. The exhaust gas flows into the exhaust port 7 when the exhaust valve 11 is opened, and is discharged to the outside through an exhaust device connected to the exhaust port 7.

  In the internal combustion engine E of the present embodiment, the intake valve 10 and the exhaust valve 11 are opened and closed at a predetermined timing and lift amount by a variable valve operating device V that is a valve operating device provided in the cylinder head 2. As shown in FIGS. 1 to 3, the variable valve operating device V is disposed in a valve operating chamber 15 formed by the cylinder head 2 and the head cover 3, and is a cam shaft 20 that is rotatably supported by the cylinder head 2. Drive cams 21, 21 provided on the cam shaft 20 and rotating integrally with the cam shaft 20, valve cams 22, 22 supported by the cam shaft 20 so as to be swingable, and valve cams 22, 22. The main rocker arms 23 and 23 that are swung and open / close the intake valve 10 and the exhaust valve 11 and the cam shaft 20 are supported so as to be swingable, and the valve driving force of the drive cam 21 is transmitted to the valve cam 22. Variable link mechanisms 30 and 30 that are link mechanisms that swing the valve cam 22, a control mechanism 60 that swings the variable link mechanisms 30 and 30, and a drive mechanism 80 that drives the control mechanism 60.

  The camshaft 20 is rotatably supported by a pair of bearings 14 attached to the cylinder head 2 and the camshaft holder 12 and is wound around a cam sprocket 16 fixed to one end portion (left end portion in FIG. 2). The driving force of the crankshaft is transmitted through 17 and is rotationally driven at half the rotational speed of the crankshaft. In this embodiment, it is assumed that the cam shaft 20 rotates in the clockwise direction in FIG.

  The bearings 14 and 14 are respectively held by a bearing holding portion 2 a formed integrally with the cylinder head 2 and a bearing holding portion 12 a formed integrally with the camshaft holder 12. The camshaft holder 12 is integrally coupled to the cylinder head 2 by bolts.

  The drive cam 21 is fixed to the cam shaft 20 by press fitting, and rotates integrally with the cam shaft 20. The drive cam 21 transmits the valve driving force of the cam shaft 20 to the valve cam 22 via the variable link mechanism 30 to swing the valve cam 22.

  The valve cam 22 is a swing cam that is swingably supported by the cam shaft 20 via a needle bearing 24, and the exhaust valve 11 (intake valve 10) is maintained in a closed state on the outer peripheral surface thereof. A base circle portion 22a and a cam crest portion 22b that opens the exhaust valve 11 (intake valve 10) by pressing down are formed.

  The main rocker arm 23 is swingably supported by a rocker shaft 25 provided on the camshaft holder 12, and a roller 23 a that contacts the valve cam 22 is rotatably attached to one end portion, and is attached to the other end portion. Is attached with an adjusting screw 23b that contacts the upper end of the exhaust valve 11 (intake valve 10).

  The variable link mechanism 30 changes the valve operating characteristics (opening / closing timing, lift amount, etc.) of the intake valve 10 and the exhaust valve 11 and swings about the camshaft 20 as shown in FIGS. A holder 31 supported so as to be swingable, a sub rocker arm 32 supported so as to be swingable on the holder 31, a connecting link 33 that swingably connects the sub rocker arm 32 and the valve cam 22, and a tip end portion of the holder 31 Are constantly biased in the direction in which the exhaust valve 11 (the intake valve 10) is closed, and the pressure spring 34 that constantly biases the sub-rocker arm 32 downward, the control spring 35 that constantly biases the sub-rocker arm 32 toward the drive cam 21. A return spring 36. FIG. 4 shows only the intake side variable link mechanism 30.

  As shown in FIGS. 4 and 5, the holder 31 is supported so as to be swingable about the camshaft 20, and is arranged at a predetermined interval in the axial direction. The first and second plates 41 and 42 are integrally coupled in the axial direction, the coupling member 43 that receives the urging force of the pressing spring 34 and the control spring 35, and the return spring fixed to the inside of the second plate 42. And a spring receiving member 44 for receiving 36 biasing force. In the present embodiment, the first plate 41 is disposed on the inner side in the axial direction of the cam shaft 20, and the second plate 42 is disposed on the outer side in the axial direction of the cam shaft 20.

  The first and second plates 41 and 42 are respectively formed with cylindrical fitting portions 41a and 42a at the base end portions, and the fitting portions 41a and 42a are integrally fixed to the cylinder head 2. The cylinder head 2, the cam shaft holder 12, and the collar 45 can be swung by being fitted to the collar 45 and the bearing holding portion 2 a of the cylinder head 2 and the bearing holding portion 12 a of the cam shaft holder 12. Supported. Accordingly, the holder 31, that is, the variable link mechanism 30 is supported by the cylinder head 2, the cam shaft holder 12, and the collar 45 so as to be swingable, and is supported so as to be swingable about the cam shaft 20.

  The fitting portion 41 a of the first plate 41 is formed with a through hole 41 b for penetrating the cam shaft 20, and a predetermined gap is provided between the through hole 41 b and the cam shaft 20. , Do not touch each other. The first plate 41 comes into contact with the collar 45 at the base end portion thereof, and an engaging portion 41 c formed to protrude from the outer peripheral surface of the base end portion comes into contact with a restriction portion 2 b formed integrally with the cylinder head 2. As a result, movement in the axial direction is restricted. Further, when the fitting portion 41a is fitted to the collar 45, the radial movement is restricted.

  The fitting portion 42a of the second plate 42 is formed with a through hole 42b for allowing the cam shaft 20 to pass therethrough, and a predetermined gap is formed between the through hole 42b and the spacer 20a of the cam shaft 20. Are provided and do not contact each other. The spacer 20 a is a cylindrical member that is inserted into the cam shaft 20 so as to be integrally rotatable so as to define an axial interval between the valve cam 22 and the bearing 14. The second plate 42 has its base end abutted against the bearing holding portions 2a and 12a, and its base end abutted against the restriction portion 2c formed integrally with the cylinder head 2 so that the second plate 42 can move in the axial direction. Be regulated. Further, the fitting portion 42a is fitted to the bearing holding portions 2a and 12a, thereby restricting the movement in the radial direction.

  As shown in FIG. 5, the collar 45 includes a collar body 45a in which a fitting hole 45b for fitting the fitting portion 41a of the first plate 41 is formed, and a radially outward direction from the outer peripheral surface of the collar body 45a. And a pair of attachment portions 45c for integrally fixing the collar 45 to the cylinder head 2. The collar 45 is integrally fixed to the cylinder head 2 by connecting the pair of mounting portions 45c to the mounting seat 2d of the cylinder head 2 with screws.

  As shown in FIG. 4, the sub rocker arm 32 is disposed between the first and second plates 41 and 42 together with the drive cam 21 and the valve cam 22. A rotating roller 32a is rotatably attached. Further, one end portion which is a fulcrum portion is swingably supported by a rivet 46 erected between the first and second plates 41 and 42 in the axial direction, and is in a position shifted in the axial direction from the fulcrum portion. The other end, which is a portion, is connected to the valve cam 22 via a connecting link 33 so as to be swingable. Further, the sub rocker arm 32, the connecting link 33, and the valve cam 22 are connected to each other by pins 33a and 33b so as to be swingable. As a result, the sub rocker arm 32 swings around the rivet 46 when the roller 32a is pressed against the rotated drive cam 21.

  One end of the pressing spring 34 is held by a holding portion 12 b that protrudes downward from the camshaft holder 12, and the other end of the pressing spring 34 protrudes upward from the coupling member 43 of the holder 31. Retained. As a result, the pressing spring 34 always urges the tip of the holder 31 downward by the urging force to press the variable link mechanism 30 in the counterclockwise direction of FIG.

  One end of the control spring 35 is held by a holding portion 43 b that protrudes from the coupling member 43 of the holder 31 toward the cam shaft 20, and the other end of the control spring 35 faces away from the cam shaft 20. Are held by the holding portion 32b. Thereby, the control spring 35 always urges the sub rocker arm 32 to the drive cam 21 by the urging force, and presses the roller 32 a of the sub rocker arm 32 against the drive cam 21 to bring it into contact therewith.

  One end of the return spring 36 is rotatably held by a holder-side spring holding portion 51 provided on the spring receiving member 44 of the holder 31, and the other end thereof is rotated by a cam-side spring holding portion 52 provided on the valve operating cam 22. Held possible. Accordingly, the return pulling 36 constantly biases the valve cam 22 in the direction in which the exhaust valve 11 (intake valve 10) is closed by the biasing force, and presses the valve cam 22 in the counterclockwise direction of FIG. . Further, since both ends of the return spring 36 are rotatably held by the holder-side spring holding portion 51 and the cam-side spring holding portion 52, respectively, the return spring 36 is curved in an arc shape when the valve cam 22 swings. There is nothing, and it expands and contracts by linear motion.

  The holder-side spring holding portion 51 includes a stay portion 53 that protrudes downward from the spring receiving member 44, and a spring support member 54 that is rotatably supported by the stay portion 53 via a pin 53a. The spring support member 54 includes a rod (spring guide rod) 54 a that penetrates the cam-side spring holding portion 52 and guides the expansion and contraction of the return spring 36, and an abutment surface 54 b that abuts one end of the return spring 36. Is formed. Furthermore, a tapered escape portion 54c is formed at the tip of the rod 54a so that the rod 54a does not come into contact with other members when the valve cam 22 is swung.

  The cam-side spring holding portion 52 is fitted to the spring seat support member 55 projecting downward from the valve cam 22 and the spring seat support member 55, and the spring slides on the spring seat support member 55. A sheet member 56. The spring seat support member 55 is formed with a convex fitting portion 55a having a convex arc shape protruding toward the holder side spring holding portion 51, and the spring seat member 56 is fitted with the convex fitting portion 55a. A concave arcuate fitting portion 56a that slides is formed.

  Further, the spring seat support member 55 is provided with a slit 55b for penetrating the rod 54a of the holder side spring holding portion 51 and a pin 55c for preventing the rod 54a from falling off.

  Further, the spring seat member 56 passes through the rod 54 a of the holder-side spring holding portion 51, and comes into contact with the through hole 56 b for guiding the sliding of the rod 54 a in the axial direction and the other end portion of the return spring 36. A contact surface 56c.

  In the variable link mechanism 30 configured as described above, when the holder 31 is swung by the control mechanism 60, the sub rocker arm 32 and the valve cam 22 are swung around the cam shaft 20 together with the holder 31. Thereby, the position of the valve cam 22 is displaced in the circumferential direction with respect to the cam shaft 20, and the circumferential phase with respect to the drive cam 21, here, the angular position or the circumferential position is changed.

  The control mechanism 60 is swingably connected to the holder 31 of the variable link mechanism 30 to swing the variable link mechanism 30. As shown in FIGS. 1 and 2, the control mechanism 60 includes a substantially cylindrical support body 61 coupled to the upper end surface of the camshaft holder 12 by a bolt and a pair fixed to the inner peripheral surface of the support body 61. Bearing 62, a substantially cylindrical first control shaft 71 rotatably supported by a support 61 via a pair of bearings 62, and an inner peripheral surface of the first control shaft 71 via a feed screw mechanism 63. The substantially cylindrical second control shaft 72 supported so as to be able to advance and retract along the rotation center line of the first control shaft 71, and the second control shaft 72 and the holders 31 and 31 of the variable link mechanisms 30 and 30 are provided. Swing links 73 and 73 are connected to each other so as to be swingable.

  The feed screw mechanism 63 includes a female screw portion 63a formed on the inner peripheral surface of the first control shaft 71 and a male screw portion 63b formed on the outer peripheral surface of the second control shaft 72 and screwed into the female screw portion 63a. And the first control shaft 71 is driven to rotate by the drive mechanism 80, whereby the second control shaft 72 is advanced and retracted along the rotation center line of the first control shaft 71.

  Further, the first control shaft 71 is integrally provided with an input gear 71a to which the rotational driving force of the drive mechanism 80 is input on the outer peripheral surface thereof.

  The second control shaft 72 is reciprocated linearly by the feed screw mechanism 63 when moving forward and backward along the rotation center line of the first control shaft 71. The guide shaft 64 fixed to the upper end portion and slidably fitted to the inner peripheral surface of the second control shaft 72 is supported by the through hole 12c of the cam shaft holder 12, and is attached to the outer peripheral surface of the second control shaft 72. The guide tube 65 is slidably fitted and is guided.

  One end of the swing link 73 is slidably connected to the tip of the second control shaft 72 via a pin 74a, and the other end is connected to the upper surface of the first plate 41 of the holder 31 via a pin 74b. It is connected so that it can swing. The swing link 73 is driven as the second control shaft 72 advances and retracts, and swings the variable link mechanism 30.

  In the control mechanism 60 configured as described above, when the second control shaft 72 is retracted by the rotation of the first control shaft 71, the swing link 73 pulls up the holder 31, and the variable link mechanism 30 and the valve cam. 22 is swung in the clockwise direction of FIG. Further, when the second control shaft 72 is advanced by the rotation of the first control shaft 71, the swing link 73 and the pressing spring 34 push down the holder 31, and the variable link mechanism 30 and the valve cam 22 are shown in FIG. It is swung counterclockwise.

  As shown in FIGS. 2 and 8, the drive mechanism 80 is coupled to the head cover 3 by bolts, and is arranged on the outside of the valve operating chamber 15. The drive motor 80 can rotate forward and backward, and the rotational driving force of the electric motor 81. Is transmitted to the control mechanism 60, and an electronic control unit 83 that controls the electric motor 81 according to the operating state of the internal combustion engine E is provided.

  The electric motor 81 includes an output shaft 81a that extends into the valve operating chamber 15 in parallel with the cylinder axis, and a drive gear 81b that meshes with the reduction gear 82 is formed at the tip of the output shaft 81a.

  The reduction gear 82 is rotatably supported by the head cover 3 and a pair of bearings 84 attached to the cover 3a that closes the upper opening of the head cover 3, and is controlled by a large gear 82a that meshes with the drive gear 81b of the electric motor 81, A small gear 82 b that meshes with the input gear 71 a of the first control shaft 71 of the mechanism 60.

  As shown in FIG. 2, the electronic control unit 83 includes a potentiometer 85 that detects the amount of swing of the valve cam 22 and the variable link mechanism 30 by detecting the amount of rotation of the first control shaft 71 of the control mechanism 60. And an operating state detecting unit 86 configured to detect an operating state of the internal combustion engine E, which includes a load detecting unit for detecting the engine load of the internal combustion engine E, an engine rotational speed detecting unit for detecting the engine rotational speed, and the like. Connected. The electronic control unit 83 controls the electric motor 81 based on the detection values input from the potentiometer 85 and the operating state detection means 86.

  As shown in FIGS. 8 and 9, the potentiometer 85 is coupled to the head cover 3 with a bolt, and the amount of rotation of the input gear 71 a of the first control shaft 71 of the control mechanism 60 is measured via the sensor drive mechanism 90. To detect.

  The sensor drive mechanism 90 meshes with the input gear 71 a of the first control shaft 71 to extract the rotation amount of the input gear 71 a, the shaft coupling 92 and the torsion coil spring 93 on the input shaft 85 a of the potentiometer 85. And a worm gear mechanism 95 that transmits the rotation of the take-out drive gear 91 to the sensor shaft 94.

  The worm gear mechanism 95 includes a worm 95a formed on the shaft of the take-out drive gear 91 rotatably supported by the camshaft holder 12 and the head cover 3, and an axis of the sensor shaft 94 rotatably supported by the head cover 3. And a worm wheel 95b that meshes with the worm 95a. Further, the worm wheel 95b is pressed against the worm 95a by the torsion coil spring 93. As a result, backlash between the worm 95a and the worm wheel 95b is prevented, and the detection accuracy of the potentiometer 85 is improved.

  Then, the electronic control unit 83 controls the electric motor 81 based on a control map in which the relationship between the operation state such as the rotation amount of the electric motor 81 and the operation state of the internal combustion engine E is set in advance, and thereby the operation state is set. Optimal valve operating characteristics are set. The actual operation of the electric motor 81 is detected by the potentiometer 85, and the detected value of the potentiometer 85 is fed back to the electronic control unit 83.

  Next, control of the valve operating characteristics of the variable valve gear V will be described with reference to FIGS.

  First, when the internal combustion engine E is in a low speed rotation range or a low load range, the drive mechanism 80 causes the second control shaft 72 of the control mechanism 60 to move toward the first position (toward the camshaft 20) as shown in FIG. The valve cam 22 occupies the position where the cam crest 22b of the valve cam 22 is farthest from the roller 23a of the main rocker arm 23. As a result, the opening timing of the exhaust valve 11 (intake valve 10) is the most retarded position, the closing timing is the most advanced position, and the minimum valve operating characteristic is obtained in which both the valve opening period and the lift amount are minimized. .

  When the cam shaft 20 is rotated in the first position, as shown in FIG. 6B, the sub rocker arm 32 swings around the rivet 46 by the cam crest of the drive cam 21 (FIG. 6). The valve cam 22 is swung around the cam shaft 20 by the connecting link 33 connected to the sub rocker arm 32 (clockwise direction in FIG. 6), and the cam nose 22b of the valve cam 22 is rotated. As a result, the main rocker arm 23 is swung around the rocker shaft 25 (clockwise direction in FIG. 6), and the exhaust valve 11 (intake valve 10) is opened with the minimum valve opening period and the minimum lift amount. Further, as the valve cam 22 swings, the spring support member 54 rotates with respect to the holder 31 and the spring seat member 56 slides on the spring seat support member 55, so that the return spring 36 is expanded and contracted. The linear motion is maintained (see a line and b line in FIG. 6).

  Next, when the internal combustion engine E shifts to a high speed rotation range or a high load range, the second control shaft 72 of the control mechanism 60 is moved from the first position to the second position by the drive mechanism 80 as shown in FIG. The valve cam 22 occupies the position where the cam crest 22b of the valve cam 22 is closest to the roller 23a of the main rocker arm 23. Thereby, the opening timing of the exhaust valve 11 (intake valve 10) becomes the most advanced angle position, the closing timing becomes the most retarded angle position, respectively, and the maximum valve operating characteristic is obtained in which both the valve opening period and the lift amount are maximized. .

  When the cam shaft 20 is rotated in the second position, as shown in FIG. 7B, the sub rocker arm 32 swings around the rivet 46 by the cam nose of the drive cam 21 (FIG. 7). The valve cam 22 is swung around the camshaft 20 (clockwise direction in FIG. 7) by the connecting link 33 connected to the sub rocker arm 32, and the cam nose 22b of the valve cam 22 is rotated. As a result, the main rocker arm 23 is swung around the rocker shaft 25 (clockwise direction in FIG. 7), and the exhaust valve 11 (intake valve 10) is opened with the maximum valve opening period and the maximum lift amount.

  In addition, when the second control shaft 72 of the control mechanism 60 is at an arbitrary intermediate position between the first position and the second position, it is between the minimum valve operating characteristic and the maximum valve operating characteristic corresponding to the intermediate position. Any intermediate valve operating characteristic can be obtained. Further, by rotating the electric motor 81 of the drive mechanism 80 in the reverse direction, the second control shaft 72 can be advanced again to shift from the second position to the first position.

  As described above, according to the variable valve gear V of the internal combustion engine E of the present embodiment, the variable link mechanism 30 includes the holder 31 supported so as to be swingable about the camshaft 20, A return spring 36 provided between the valve cam 22 and constantly urging the valve cam 22 to a position where the exhaust valve 11 (intake valve 10) is closed, and a holder 31 are provided to hold one end of the return spring 36. A holder-side spring holding part 51 and a cam-side spring holding part 52 provided on the valve cam 22 and holding the other end of the return spring 36. The holder-side spring holding part 51 and the cam-side spring holding part Since both of the portions 52 rotatably hold both ends of the return spring 36, the holder-side spring holding portion 51 and the cam-side spring are moved along with the swing of the valve cam 22. When the holding portion 52 rotates with respect to the holder 31 and the valve cam 22, the contact surface 54 b of the spring support member 54 and the contact surface 56 c of the spring seat member 56 are always maintained in parallel, and the return spring 36 is expanded and contracted. Therefore, the stress acting on the return spring 36 can be relaxed. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

  Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the spring support member 54 of the holder side spring holding part 51 is provided with the rod 54a penetrating the cam side spring holding part 52 and the cam side spring. Since the return spring 36 is guided by the 54a rod in order to provide the through hole 56b for allowing the rod 54a to pass through the spring seat member 56 of the holding portion 52 and guiding the axial sliding thereof, the return spring 36 is linearly moved. Exercise can be easily maintained.

  As a modification of the present embodiment, as shown in FIG. 10, a spring seat support member 55 and a spring seat member 56 are provided in the holder side spring holding portion 51, and a stay portion 53 and a cam side spring holding portion 52 are provided. A spring support member 54 may be provided. In this case, the friction of the oscillating valve cam 22 can be reduced.

(Second Embodiment)
Next, a second embodiment of the valve operating apparatus for an internal combustion engine according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.
FIG. 11 is an explanatory view of a second embodiment of a valve operating apparatus for an internal combustion engine according to the present invention. FIG. 11 (a) is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of the present embodiment, as shown in FIG. 11, the return spring 36 is rotatably held at one end by a holder side spring holding portion 101 provided on the spring receiving member 44 of the holder 31, and the other end. The portion is rotatably held by a cam side spring holding portion 102 provided in the valve cam 22.

  The holder-side spring holding portion 101 has a spring seat support member 103 projecting downward from the spring receiving member 44, and a spring that fits the spring seat support member 103 and slides on the spring seat support member 103. A sheet member 104. The spring seat support member 103 is formed with a convex fitting portion 103a having a convex arc shape protruding toward the cam-side spring holding portion 102, and the spring seat member 104 is fitted with the convex fitting portion 103a. A concave arc-shaped concave fitting portion 104a that slides is formed. Further, the spring seat member 104 is formed with an abutment surface 104 b that abuts against one end of the return spring 36.

  The cam side spring holding part 102 is fitted to the spring seat support member 105 projecting downward from the valve cam 22 and the spring seat support member 105, and the spring slides on the spring seat support member 105. A sheet member 106. The spring seat support member 105 is formed with a convex fitting portion 105a having a convex arc shape protruding toward the holder-side spring holding portion 101, and the spring seat member 106 is fitted with the convex fitting portion 105a. A concave arcuate fitting portion 106a that slides is formed. Further, the spring seat member 106 is formed with a contact surface 106 b that contacts the other end of the return spring 36.

  As described above, according to the variable valve gear V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 101 is fitted to the spring seat support member 103 provided on the holder 31 and the spring seat support member 103. And a spring seat member 104 that slides on the spring seat support member 103 and is provided with a contact surface 104b with the return spring 36. The cam-side spring holding portion 102 is attached to the valve cam 22. A spring seat support member 105 provided, and a spring seat member 106 that fits the spring seat support member 105 and slides on the spring seat support member 105 and is provided with a contact surface 106b with the return spring 36. Convex arcuate convex fitting to spring seat support members 103 and 105 103a and 105a are formed, and concave fitting portions 104a and 106a each having a concave arc shape are formed on the spring seat members 104 and 106, respectively. Therefore, as the valve cam 22 swings, the spring seat member 104 is moved to the spring seat. While the support member 103 slides and the spring seat member 106 slides on the spring seat support member 105, the contact surface 104b of the spring seat member 104 and the contact surface 106b of the spring seat member 106 are always parallel. Thus, the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relaxed. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 101 is fitted and slid with the spring seat support member 103 provided on the holder 31 and the spring seat support member 103. The cam-side spring holding portion 102 is provided with a spring seat support member 105 provided on the valve operating cam 22, and a spring seat member 106 fitted and slid with the spring seat support member 105. Since the structure of the variable link mechanism 30 can be simplified and reduced in weight, the drive performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Third embodiment)
Next, a third embodiment of the valve gear for the internal combustion engine according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.
FIGS. 12A and 12B are explanatory views of a third embodiment of a valve operating apparatus for an internal combustion engine according to the present invention. FIG. 12A is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of the present embodiment, as shown in FIG. 12, one end of the return spring 36 is rotatably held by a holder-side spring holding portion 111 provided on the spring receiving member 44 of the holder 31, and the other end The portion is rotatably held by a cam side spring holding portion 112 provided on the valve cam 22.

  The holder-side spring holding part 111 is fitted to the spring seat support member 113 projecting downward from the spring receiving member 44 and the spring seat support member 113, and the spring slides on the spring seat support member 113. A sheet member 114. The spring seat support member 113 is formed with a concave arc-shaped concave fitting portion 113a that is recessed in a direction away from the cam-side spring holding portion 112, and the spring seat member 114 includes the concave fitting portion 113a and the concave fitting portion 113a. Convex arc-shaped convex fitting portions 114a that fit and slide are formed. Further, the spring seat member 114 is formed with an abutment surface 114 b that abuts against one end of the return spring 36.

  The cam-side spring holding portion 112 is fitted to the spring seat support member 115 projecting downward from the valve cam 22 and the spring seat support member 115, and the spring slides on the spring seat support member 115. Sheet member 116. The spring seat support member 115 is formed with a concave arc-shaped concave fitting portion 115a that is recessed in a direction away from the holder-side spring holding portion 111, and the spring seat member 116 includes the concave fitting portion 115a. A convex arc-shaped convex fitting portion 116a that fits and slides is formed. Further, the spring seat member 116 is formed with a contact surface 116 b that contacts the other end of the return spring 36.

  As described above, according to the variable valve gear V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 111 is fitted to the spring seat support member 113 provided on the holder 31 and the spring seat support member 113. And a spring seat member 114 that slides on the spring seat support member 113 and is provided with an abutment surface 114b with the return spring 36. A spring seat support member 115 provided, and a spring seat member 116 that fits the spring seat support member 115, slides on the spring seat support member 115, and is provided with a contact surface 116b with the return spring 36. Concave fitting with a concave arc shape to spring seat support members 113 and 115 113a and 115a are formed, and convex arcuate fitting portions 114a and 116a are formed on the spring seat members 114 and 116, respectively. Therefore, as the valve cam 22 swings, the spring seat member 114 is moved to the spring seat. While sliding on the support member 113 and the spring seat member 116 sliding on the spring seat support member 115, the contact surface 114b of the spring seat member 114 and the contact surface 116b of the spring seat member 116 are always parallel. Thus, the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relaxed. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 111 is fitted and slid with the spring seat support member 113 provided on the holder 31 and the spring seat support member 113. The cam-side spring holding portion 112 includes a spring seat support member 115 provided on the valve operating cam 22, and a spring seat member 116 that fits and slides with the spring seat support member 115. Since the structure of the variable link mechanism 30 can be simplified and reduced in weight, the drive performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the valve gear for an internal combustion engine according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.
FIGS. 13A and 13B are explanatory views of a fourth embodiment of a valve operating apparatus for an internal combustion engine according to the present invention. FIG. 13A is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of this embodiment, as shown in FIG. 13, one end of the return spring 36 is rotatably held by a holder-side spring holding portion 121 provided on the spring receiving member 44 of the holder 31, and the other end The portion is rotatably held by a cam side spring holding portion 122 provided on the valve cam 22.

  The holder-side spring holding portion 121 includes a stay portion 123 that protrudes downward from the spring receiving member 44 and a spring support member 124 that is rotatably supported by the stay portion 123 via a pin 123a. Further, the spring support member 124 is formed with a contact surface 124 a that contacts one end of the return spring 36.

  The cam-side spring holding portion 122 includes a stay portion 125 that projects downward from the valve cam 22 and a spring support member 126 that is rotatably supported by the stay portion 125 via a pin 125a. Further, the spring support member 126 is formed with a contact surface 126 a that contacts the other end of the return spring 36.

  As described above, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 is rotatably supported by the holder 31 via the pin 123a. The cam-side spring holding portion 122 is rotatably supported by the valve operating cam 22 via a pin 125a, and a contact surface 126a with the return spring 36 is provided. Since the spring support member 126 is provided, the spring support member 124 rotates with respect to the holder 31 and the spring support member 126 rotates with respect to the valve cam 22 as the valve cam 22 swings. The contact surface 124a of the spring support member 124 and the contact surface 126a of the spring support member 126 are always kept parallel. Is, it is possible to maintain the expansion and contraction of the return spring 36 to linear motion, it is possible to relieve the stress acting on the return spring 36. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 includes the spring support member 124 that is rotatably supported by the holder 31 via the pin 123a, and the cam Since the side spring holding part 122 includes the spring support member 126 that is rotatably supported by the valve cam 22 via the pin 125a, the frictional resistance generated in the variable link mechanism 30 can be reduced. The driving performance of the device V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the valve gear for an internal combustion engine according to the present invention will be described with reference to FIG. In addition, about the same or equivalent part as 1st Embodiment, 2nd Embodiment, and 4th Embodiment, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted or simplified.
FIGS. 14A and 14B are explanatory views of a fifth embodiment of a valve operating apparatus for an internal combustion engine according to the present invention. FIG. 14A is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of this embodiment, as shown in FIG. 14, the return spring 36 is rotatably held at one end by a holder-side spring holding portion 121 provided on the spring receiving member 44 of the holder 31. The portion is rotatably held by a cam side spring holding portion 102 provided in the valve cam 22.

  As described above, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 is rotatably supported by the holder 31 via the pin 123a. The cam-side spring holding portion 102 is fitted with the spring seat support member 105 provided on the valve operating cam 22 and the spring seat support member 105, and has a spring seat. A spring seat member 106 that slides on the support member 105 and is provided with a contact surface 106b with the return spring 36, and forms a convex arc-shaped convex fitting portion 105a on the spring seat support member 105, In order to form the concave arc-shaped concave fitting portion 106a in the spring seat member 106, the valve cam 22 is not swung. Along with this, the spring support member 124 rotates with respect to the holder 31 and the spring seat member 106 slides on the spring seat support member 105, whereby the contact surface 124 a of the spring support member 124 and the spring seat member 106. The contact surface 106b is always maintained in parallel and the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relieved. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 includes the spring support member 124 that is rotatably supported by the holder 31 via the pin 123a, and the cam The side spring holding portion 102 includes a spring seat support member 105 provided on the valve cam 22 and a spring seat member 106 that fits and slides on the spring seat support member 105. Since the frictional resistance generated on the holder 31 side can be reduced, the driving performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Sixth embodiment)
Next, a sixth embodiment of the valve gear for an internal combustion engine according to the present invention will be described with reference to FIG. In addition, about the same or equivalent part as 1st Embodiment, 3rd Embodiment, and 4th Embodiment, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted or simplified.
FIGS. 15A and 15B are explanatory views of a valve operating apparatus for an internal combustion engine according to a sixth embodiment of the present invention. FIG. 15A is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of the present embodiment, as shown in FIG. 15, the return spring 36 is rotatably held at one end by a holder side spring holding portion 121 provided on the spring receiving member 44 of the holder 31, and the other end. The portion is rotatably held by a cam side spring holding portion 112 provided on the valve cam 22.

  As described above, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 is rotatably supported by the holder 31 via the pin 123a. The cam-side spring holding portion 112 is fitted with the spring seat support member 115 and the spring seat support member 115 provided on the valve operating cam 22, and has a spring seat. A spring seat member 116 that slides on the support member 115 and is provided with a contact surface 116b with the return spring 36. The spring seat support member 115 is formed with a concave arc-shaped concave fitting portion 115a. In order to form a convex arc-shaped convex fitting portion 116a in the spring seat member 116, the valve cam 22 is not swung. Accordingly, the spring support member 124 rotates with respect to the holder 31 and the spring seat member 116 slides on the spring seat support member 115, whereby the contact surface 124 a of the spring support member 124 and the spring seat member 116. The contact surface 116b is always maintained in parallel and the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relieved. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 121 includes the spring support member 124 that is rotatably supported by the holder 31 via the pin 123a, and the cam Since the side spring holding portion 112 includes a spring seat support member 115 provided on the valve seat cam 22 and a spring seat member 116 that fits and slides with the spring seat support member 115, the structure on the side of the valve seat cam 22 is provided. Since the frictional resistance generated on the holder 31 side can be reduced, the driving performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Seventh embodiment)
Next, a seventh embodiment of the valve gear for an internal combustion engine according to the present invention will be described with reference to FIG. In addition, about the same or equivalent part as 1st Embodiment, 2nd Embodiment, and 4th Embodiment, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted or simplified.
FIG. 16 is an explanatory view of a seventh embodiment of a valve operating apparatus for an internal combustion engine according to the present invention, where (a) is a view of a link mechanism before the valve cam swings, and (b) is when the valve cam swings. It is a figure of a link mechanism.

  In the variable link mechanism 30 according to the present embodiment, as shown in FIG. 16, the return spring 36 is rotatably held at one end by a holder-side spring holding portion 101 provided on the spring receiving member 44 of the holder 31. The portion is rotatably held by a cam side spring holding portion 122 provided on the valve cam 22.

  As described above, according to the variable valve gear V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 101 is fitted to the spring seat support member 103 provided on the holder 31 and the spring seat support member 103. And a spring seat member 104 that slides on the spring seat support member 103 and is provided with a contact surface 104b with the return spring 36, and has a convex arc-shaped convex fit with the spring seat support member 103 Part 103a is formed, and a concave arc-shaped concave fitting part 104a is formed on the spring seat member 104. The cam-side spring holding part 122 is rotatably supported by the valve operating cam 22 via a pin 125a, and the return Since it has the spring support member 126 provided with the contact surface 126a with the spring 36, the valve cam 22 With the movement, the spring seat member 104 slides on the spring seat support member 103 and the spring support member 126 rotates with respect to the valve cam 22, whereby the contact surface 104 b of the spring seat member 104 and the spring are rotated. Since the abutting surface 126a of the support member 126 is always maintained in parallel, the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relieved. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 101 is fitted and slid with the spring seat support member 103 provided on the holder 31 and the spring seat support member 103. The cam-side spring holding portion 122 includes a spring support member 126 that is rotatably supported by the valve operating cam 22 via a pin 125a, so that the structure on the holder 31 side is simplified. Thus, the weight can be reduced, and the frictional resistance generated when the valve cam 22 swings can be reduced, so that the drive performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Eighth embodiment)
Next, an eighth embodiment of the valve gear for an internal combustion engine according to the present invention will be described with reference to FIG. In addition, about the same or equivalent part as 1st Embodiment, 3rd Embodiment, and 4th Embodiment, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted or simplified.
FIG. 17 is an explanatory view of an eighth embodiment of a valve operating apparatus for an internal combustion engine according to the present invention. FIG. 17 (a) is a view of a link mechanism before the valve cam swings, and FIG. It is a figure of a link mechanism.

  In the variable link mechanism 30 of this embodiment, as shown in FIG. 17, the return spring 36 is rotatably held at one end by a holder-side spring holding portion 111 provided on the spring receiving member 44 of the holder 31. The portion is rotatably held by a cam side spring holding portion 122 provided on the valve cam 22.

  As described above, according to the variable valve gear V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 111 is fitted to the spring seat support member 113 provided on the holder 31 and the spring seat support member 113. And a spring seat member 114 that slides on the spring seat support member 113 and is provided with a contact surface 114b with the return spring 36. The cam seat spring holding portion 122 is rotatably supported by the valve operating cam 22 via the pin 125a, and the return is formed by forming the portion 113a and forming the convex arcuate convex fitting portion 114a on the spring seat member 114. Since it has the spring support member 126 provided with the contact surface 126a with the spring 36, the valve cam 22 With the movement, the spring seat member 114 slides on the spring seat support member 113 and the spring support member 126 rotates with respect to the valve cam 22, whereby the contact surface 114 b of the spring seat member 114 and the spring are rotated. Since the abutting surface 126a of the support member 126 is always maintained in parallel, the expansion and contraction of the return spring 36 can be maintained in a linear motion, so that the stress acting on the return spring 36 can be relieved. Thereby, since the return spring 36 can be made small, the variable valve apparatus V can be reduced in size.

Further, according to the variable valve operating apparatus V of the internal combustion engine E of the present embodiment, the holder-side spring holding portion 111 is fitted and slid with the spring seat support member 113 provided on the holder 31 and the spring seat support member 113. The cam-side spring holding portion 122 includes a spring support member 126 that is rotatably supported by the valve operating cam 22 via a pin 125a, so that the structure on the holder 31 side is simplified. Thus, the weight can be reduced, and the frictional resistance generated when the valve cam 22 swings can be reduced, so that the drive performance of the variable valve gear V can be improved.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above embodiment, the case where both the holder side spring holding part and the cam side spring holding part hold the end part of the return spring rotatably is illustrated, but the holder side spring holding part and the cam side spring holding part Either one may hold the end of the return spring rotatably. In this case, the curvature of the return spring accompanying the swing of the valve cam can be reduced, so that the stress acting on the return spring can be relaxed.

1 is a partially cutaway cross-sectional view of an internal combustion engine to which a first embodiment of a valve gear for an internal combustion engine according to the present invention is applied. FIG. 2 is a cross-sectional view taken along line WW in FIG. 1. It is the partially cutaway sectional view which looked at the cylinder head of the state where the head cover was removed from the upper part. It is explanatory drawing of the valve operating apparatus shown in FIG. 1, (a) is a figure of the link mechanism in the state where a part of plate was removed, (b) is a sectional view taken along line XX of (a). It is explanatory drawing of the color shown in FIG. 2, (a) is an enlarged plan view of color vicinity, (b) is the YY arrow directional cross-sectional view of (a). It is explanatory drawing of the valve operating apparatus of the state in which the minimum valve operation characteristic is acquired, (a) is a figure of the link mechanism before a valve cam swing, (b) is a figure of the link mechanism at the time of valve cam swing. is there. It is explanatory drawing of the valve operating apparatus of the state in which the maximum valve operation characteristic is acquired, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is a figure of the link mechanism at the time of valve-operating cam rocking. is there. It is the figure which looked at the cylinder head of the state which fractured | ruptured a part of head cover from the upper direction. It is a ZZ line perspective sectional view of Drawing 8. It is explanatory drawing of the modification of 1st Embodiment, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is a figure of the link mechanism at the time of valve-operating cam rocking. It is explanatory drawing of 2nd Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before a valve cam swing, (b) is the link mechanism at the time of a valve cam swing. FIG. It is explanatory drawing of 3rd Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is the link mechanism at the time of valve-operating cam rocking FIG. It is explanatory drawing of 4th Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is the link mechanism at the time of valve-operating cam rocking FIG. It is explanatory drawing of 5th Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is the link mechanism at the time of valve-operating cam rocking FIG. It is explanatory drawing of 6th Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before a valve cam swing, (b) is the link mechanism at the time of a valve cam swing. FIG. It is explanatory drawing of 7th Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is the link mechanism at the time of valve-operating cam rocking FIG. It is explanatory drawing of 8th Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention, (a) is a figure of the link mechanism before valve-operating cam rocking, (b) is the link mechanism at the time of valve-operating cam rocking FIG.

Explanation of symbols

E Internal combustion engine 1 Cylinder 2 Cylinder head 3 Head cover 10 Intake valve (engine valve)
11 Exhaust valve (engine valve)
V Variable valve gear (valve valve)
20 camshaft 21 drive cam 22 valve cam 23 main rocker arm 30 variable link mechanism (link mechanism)
31 Holder 32 Sub rocker arm 33 Connecting link 34 Pressing spring 35 Control spring 36 Return spring 51, 101, 111, 121 Holder side spring holding portion 53, 123, 125 Stay portion 53a, 123a, 125a Pin 54, 124, 126 Spring support member 54a Rod (Spring guide rod)
54b, 104b, 114b, 124a Contact surface 56c, 106b, 116b, 126a Contact surface
52, 102, 112, 122 Cam side spring holding portion 55, 103, 105, 113, 115 Spring seat support member 55a, 103a, 105a, 114a, 116a Convex fitting portion 56, 104, 106, 114, 116 Spring seat member 56a, 104a, 106a, 113a, 115a Recessed fitting portion 56b Through hole 60 Control mechanism 71 First control shaft 72 Second control shaft 80 Drive mechanism 81 Electric motor 82 Reduction gear 83 Electronic control unit

Claims (8)

A camshaft rotatably supported by the cylinder head and rotating in synchronization with the rotation of the internal combustion engine;
A drive cam provided on the camshaft and integrally rotating with the camshaft;
A valve cam that is swingably supported by the cam shaft and opens and closes the engine valve;
A link mechanism that is swingably supported about the cam shaft, transmits a valve driving force of the drive cam to the valve cam, and swings the valve cam;
A control mechanism for swinging the link mechanism;
A drive mechanism for driving the control mechanism,
In a valve operating apparatus for an internal combustion engine that can change a valve operating characteristic that the engine valve opens and closes at a swing position of the link mechanism swung by the control mechanism,
The link mechanism is
A holder supported so as to be swingable about the cam shaft;
A return spring that is provided between the holder and the valve cam, and constantly biases the valve cam to a position where the engine valve is closed;
A holder-side spring holding portion that is provided in the holder and holds one end of the return spring;
A cam-side spring holding portion that is provided on the valve cam and holds the other end of the return spring;
The valve operating device for an internal combustion engine, wherein at least one of the holder side spring holding portion and the cam side spring holding portion rotatably holds an end portion of the return spring.   2. The valve operating apparatus for an internal combustion engine according to claim 1, wherein both the holder-side spring holding portion and the cam-side spring holding portion hold both ends of the return spring rotatably. The holder-side spring holding portion is fitted to the spring seat support member provided on the holder and the spring seat support member, and slides on the spring seat support member, and a contact surface with the return spring is provided. A spring seat member provided,
The cam-side spring holding portion is fitted to the spring seat support member provided on the valve cam and the spring seat support member, and slides on the spring seat support member to contact the return spring. A spring seat member provided with a surface,
3. The valve operating apparatus for an internal combustion engine according to claim 1, wherein one of the spring seat support member and the spring seat member has a convex arc shape and the other has a concave arc shape. The holder-side spring holding portion includes a spring support member that is rotatably supported by the holder via a pin and provided with a contact surface with the return spring,
The said cam side spring holding | maintenance part is rotatably supported by the said valve operating cam via a pin, and has a spring support member with which a contact surface with the said return spring is provided, The Claim 1 or 2 characterized by the above-mentioned. A valve operating apparatus for an internal combustion engine as described. The holder-side spring holding portion includes a spring support member that is rotatably supported by the holder via a pin and provided with a contact surface with the return spring,
The cam-side spring holding portion is fitted to the spring seat support member provided on the valve cam and the spring seat support member, and slides on the spring seat support member to contact the return spring. A spring seat member provided with a surface,
3. The valve operating apparatus for an internal combustion engine according to claim 1, wherein one of the spring seat support member and the spring seat member has a convex arc shape and the other has a concave arc shape. The holder-side spring holding portion is fitted to the spring seat support member provided on the valve cam and the spring seat support member, and slides on the spring seat support member and comes into contact with the return spring. A spring seat member provided with a surface,
Either one of the spring seat support member and the spring seat member has a convex arc shape, the other has a concave arc shape,
The said cam side spring holding | maintenance part is rotatably supported by the said holder via the pin, and has a spring support member with which a contact surface with the said return spring is provided, The Claim 1 or 2 characterized by the above-mentioned. A valve operating device for an internal combustion engine. While providing either one of the holder side spring holding portion and the cam side spring holding portion with a spring guide rod penetrating the other spring holding portion,
The valve for an internal combustion engine according to any one of claims 3 to 6, wherein the other spring holding portion is provided with a through-hole through which the spring guide rod passes and guides sliding in the axial direction. apparatus. The contact surface between the holder-side spring holding portion and the return spring and the contact surface between the cam-side spring holding portion and the return spring are always parallel.
The valve operating apparatus for an internal combustion engine according to any one of claims 1 to 7, wherein the holder side spring holding portion and the cam side spring holding portion rotate.

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