JP6827904B2 - Variable valve gear for internal combustion engine - Google Patents

Description

The present invention makes it possible to interlock and connect with a low-speed cam and a camshaft having a high-speed cam and an engine valve urged in the valve closing direction, and to swing by following the low-speed cam. A first rocker arm and a second rocker arm arranged at a position adjacent to the first rocker arm so as to swing according to the high-speed cam while allowing the engine valve to be free. A rocker shaft having an axis parallel to the camshaft and commonly supporting the first rocker arm and the second rocker arm to the cylinder head of the engine body, and a connection in which the first rocker arm and the second rocker arm are connected. A switching pin urged toward the disconnection position side while allowing movement between the position and the connection release position for releasing the connection state, and a pressing force applied to the switching pin toward the connection position side. An actuator attached to a specific side wall of the side wall of the cylinder head of the engine body while having an output rod that can come into contact with the switching pin, and a spring that rotationally urges the second rocker arm toward the high-speed cam side. The present invention relates to a variable valve device for an internal combustion engine.

An engine valve such as an intake valve is interlocked and connected to the first rocker arm that can swing according to the low-speed cam, and the second rocker arm and the first rocker arm that swing according to the high-speed cam are connected by a switching pin. The disconnection is switched by a solenoid attached to the side wall of the cylinder head, and the engine valve opens and closes with the operating characteristics corresponding to the cam profile of the low-speed cam and the operating characteristics corresponding to the cam profile of the high-speed cam. A variable valve device for an internal combustion engine capable of switching between states is already known, for example, in Patent Document 1.

International Publication 2017/06516 Pamphlet

By the way, in the variable valve gear disclosed in Patent Document 1, the first rocker arm interlocked with and connected to the engine valve is arranged between the second rocker arm and the solenoid, and the second rocker arm is rotated toward the high-speed cam side. An urging spring is arranged between the second rocker arm and the shaft support of the cylinder head on the opposite side of the first rocker arm from the solenoid. Therefore, it is necessary to secure a space for arranging the spring between the second rocker arm and the shaft support portion, which leads to an increase in the size of the variable valve gear.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a variable valve gear for an internal combustion engine capable of miniaturization.

In order to achieve the above object, the present invention is interlocked with and connected to a low-speed cam and a camshaft having a high-speed cam and an engine valve urged in the valve closing direction, and is driven by the low-speed cam. A first rocker arm that can swing, and a position adjacent to the first rocker arm that swings according to the high-speed cam while allowing it to be free with respect to the engine valve. A second rocker arm to be arranged, a rocker shaft having an axis parallel to the camshaft and commonly supporting the first rocker arm and the second rocker arm to the cylinder head of the engine body , the first rocker arm and the first rocker arm. 2 A switching pin that is urged toward the disconnection position side while enabling movement between the connection position that connects the rocker arm and the connection release position that releases the connection state, and the switching pin that faces the connection position side. An actuator attached to a specific side wall of the side wall of the cylinder head of the engine body while having an output rod capable of contacting the switching pin so as to apply a pressing force, and the second rocker arm to the high-speed cam. In a variable valve device of an internal combustion engine including a spring that urges the engine to rotate sideways, the second rocker arm is arranged between the first rocker arm and the specific side wall, and is located between the engine body and the second rocker arm. The first feature is that the intervening spring is arranged at a position interposed between the second rocker arm and the specific side wall while overlapping with the output rod when viewed from a direction along the cylinder axis of the engine body. And.

Further, in addition to the configuration of the first feature, the present invention is a torsion spring in which a roller that rolls and contacts the high-speed cam is rotatably supported by the second rocker arm via a cylindrical support shaft. The second feature is that one end of the spring is inserted into the support shaft and engaged with the support shaft, and the other end of the spring is engaged with the engine body side.

The third feature of the present invention is that, in addition to the configuration of the second feature, the other end of the spring is engaged with the cylinder head.

In the present invention, in addition to any of the configurations of the first to third features, the second rocker arm is provided with a fitting hole for slidably fitting the switching pin, and one of the switching pins. A fourth feature is the formation of a notched recess that exposes the portion to the outside.

In the present invention, in addition to the configuration of the fourth feature, the notch recess is formed at the end of the second rocker arm on the actuator side, and the end of the output rod on the switching pin side is the cylinder. The fifth feature is that it is arranged in the notch recess when viewed from the direction along the axis.

Further, in the present invention, in addition to the configuration of the fifth feature, the notch recess is formed in the second rocker arm so as to open on the side opposite to the rocker shaft, and has a diameter smaller than that of the switching pin. The sixth feature is that the axis of the output rod is set at a position offset from the axis of the switching pin to the side opposite to the rocker shaft.

The left side wall 27c of the embodiment corresponds to a specific side wall of the present invention, the intake valve 41 of the embodiment corresponds to the engine valve of the present invention, and the intake side first rocker arm 49 of the embodiment corresponds to the invention. The second rocker arm 50 on the intake side of the embodiment corresponds to the first rocker arm, the second rocker arm 50 on the intake side of the embodiment corresponds to the second rocker arm of the present invention, and the intake side rocker shaft 75 of the embodiment corresponds to the rocker shaft of the present invention. The solenoid 80 of the above corresponds to the actuator of the present invention.

According to the first feature of the present invention, the second rocker arm is located between the first rocker arm and the actuator, and the spring overlaps the output rod of the actuator when viewed from the direction along the cylinder axis of the engine body, and the side wall of the cylinder head. Of these, since it is arranged at a position interposed between the side wall to which the actuator is mounted and the second rocker arm, the spring is arranged by effectively utilizing the space between the actuator and the second rocker arm, and is along the axis of the camshaft. The variable valve device can be miniaturized in the direction.

Further, according to the second feature of the present invention, one end of the spring has a simple structure using a cylindrical support shaft provided on the second rocker arm so as to rotatably support the roller that rolls and contacts the high-speed cam. Since the portions are engaged, a special special member for engaging one end portion of the spring is not required, and the number of parts can be reduced.

According to the third feature of the present invention, since the other end of the spring is engaged with the cylinder head, a special special member for engaging the other end of the spring is not required, and the number of parts is reduced. can do.

According to the fourth feature of the present invention, since a part of the switching pin is exposed to the outside, it becomes easy to guide the lubricating oil between the inner surface of the fitting hole of the second rocker arm and the outer surface of the switching pin. be able to.

According to the fifth feature of the present invention, a notch recess is formed at the end of the second rocker arm on the actuator side, and the end of the output rod on the switching pin side is inside the notch recess when viewed from the direction along the cylinder axis. Therefore, the distance between the actuator and the second rocker arm can be shortened, and the variable valve gear can be further miniaturized in the direction along the axis of the camshaft and the rocker shaft.

Further, according to the sixth feature of the present invention, the notch recess is opened on the side opposite to the rocker shaft to be formed on the second rocker arm, and the axis of the output rod having a diameter smaller than that of the switching pin is the axis of the switching pin. Since it is offset to the opposite side of the rocker shaft, the contact area between the small diameter force rod and the switching pin is reduced while avoiding the output rod interfering with the second rocker arm that swings around the axis of the rocker shaft. It is possible to secure a relatively large size so that the switching pin can be easily pressed.

It is a left side view of a motorcycle. It is a left side view of the main part of an internal combustion engine. It is a 3-3 line arrow view of FIG. FIG. 3 is a sectional view taken along line 4-4 of FIG. It is a perspective view which shows the cylinder head and the variable valve gear in a state where a head cover is omitted. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 6 is a sectional view taken along line 7-7 of FIG. 8-8 is a cross-sectional view taken along the line 8-8 of FIG.

Embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, up / down, left / right, and front / rear refer to the directions seen by the occupant in the motorcycle.

First, in FIG. 1, the body frame F of a scooter-type motorcycle has a front end of a front fork 11 that pivotally supports the front wheel WF and a head pipe 13 that rotatably supports a steering handle 12 connected to the front fork 11. The power unit P, which exerts the power to drive the rear wheel WR, is supported so as to be swingable up and down at the intermediate portion in the front-rear direction of the vehicle body frame F.

The power unit P includes an internal combustion engine E arranged in front of the rear wheel WR and a transmission device M for transmitting the output of the internal combustion engine E to the rear wheel WR, and the transmission device M is an engine main body of the internal combustion engine E. A rear cushion unit 16 is provided between the rear portion of the transmission case 15 and the rear portion of the vehicle body frame F, which is connected to 14 and housed in a transmission case 15 extending to the left side of the rear wheel WR.

The vehicle body frame F and a part of the power unit P are formed by a vehicle body cover 17 having a pair of left and right footrest portions 18 on which the occupant's feet are placed and a floor tunnel portion 19 that rises upward between the both footrest portions 18. It is covered, and the vehicle body cover 17 is attached to the vehicle body frame F. Further, a occupant seat 20 arranged behind the floor tunnel portion 19 and a passenger seat 21 arranged behind the occupant seat 20 are arranged on the vehicle body cover 17.

With reference to FIGS. 2 to 4, the engine body 14 of the internal combustion engine E includes a crankcase 25 that rotatably supports a crankshaft 24 (see FIG. 1) having an axis extending in the vehicle width direction, and a piston. A cylinder block 26 having a cylinder bore 30 (see FIG. 4) for slidably fitting 29 (see FIG. 4) and being coupled to the crankcase 25, and a cylinder head 27 coupled to the cylinder block 26. A head cover 28 coupled to the cylinder head 27 is provided. The cylinder axis C of the engine body 14, that is, the axis of the cylinder bore 30, is slightly inclined forward, and the piston 29 is connected to the crankshaft 24.

The intake device 32 for supplying air to the combustion chamber 31 formed between the cylinder block 26 and the cylinder head 27 so as to face the top of the piston 29 is located on the left side of the rear wheel WR and above the transmission case 15. The fuel injection valve 35 includes an air cleaner 33 arranged in the air cleaner 33 and supported by the transmission case 15 and a throttle body 34 arranged between the air cleaner 33 and the cylinder head 27, and the fuel injection valve 35 is the throttle body 34 and the cylinder. It is attached to the upper part of the intake pipe 36 connecting between the upper side walls 27a of the head 27.

An exhaust device 38 for exhausting exhaust gas from the combustion chamber 31 is connected to the lower side wall 27b of the cylinder head 27, and the exhaust device 38 is connected to the engine body 14 from the lower side wall 27b of the cylinder head 27. It is provided with an exhaust pipe 39 extending rearward below the exhaust pipe 39 and an exhaust muffler (not shown) arranged on the right side of the rear wheel WR so as to be connected to the downstream end of the exhaust pipe 39.

The cylinder head 27 has an intake valve 41 as a pair of engine valves for controlling intake from the intake device 32 to the combustion chamber 31, and exhaust control from the combustion chamber 31 to the exhaust device 38. A pair of exhaust valves 42 for opening and closing are arranged so as to be openable and closable, both intake valves 41 are urged in the valve closing direction by the valve spring 43, and both exhaust valves 42 are urged in the valve closing direction by the valve spring 44. To. Further, on the left side wall 27c of the cylinder head 27, a spark plug 45 whose tip faces the combustion chamber 31 is attached.

With reference to FIGS. 5 to 7, in the valve operating chamber 46 formed between the cylinder head 27 and the head cover 28, the opening / closing operation characteristics of the intake valve 41 are changed according to the engine speed. A variable valve gear 47 that opens and closes the intake valve 41 and the exhaust valve 42 is accommodated.

The variable valve gear 47 includes a single camshaft 48 that is common to both intake valves 41 and both exhaust valves 42 and is arranged between both intake valves 41 and both exhaust valves 42, and both intake valves 41 and the cam. It includes intake-side first and second rocker arms 49 and 50 interposed between shafts 48, and a single exhaust-side rocker arm 51 interposed between both exhaust valves 42 and the camshaft 48.

The camshaft 48 has an axis parallel to the crankshaft 24, is arranged at positions spaced apart along the axis of the camshaft 48, and projects integrally with the cylinder head 27. It is rotatably supported by the first and second support walls 52 and 53. The first and second support walls 52 and 53 are formed so as to extend in a direction orthogonal to the axis of the camshaft 48, and the first support wall 52 is integrally connected to the left side wall 27c of the cylinder head 27. The second support wall 53 is arranged at a position spaced inward from the right side wall 27d of the cylinder head 27. Moreover, at both ends in the longitudinal direction of the first support wall 52, that is, at both upper and lower ends, boss portions 52a and 52b for inserting the stud bolts 54 and 55 for connecting the cylinder block 26 and the cylinder head 27 to the crankcase 25 are provided. A boss that is integrally formed and has stud bolts 56 and 57 for connecting the cylinder block 26 and the cylinder head 27 to the crankcase 25 at both ends in the longitudinal direction of the second support wall 53, that is, at both upper and lower ends. The portions 53a and 53b are integrally formed.

A sprocket 58 is fixedly attached to the end of the camshaft 48 protruding from the second support wall 53 toward the right side wall 27d of the cylinder head 27, and the sprocket 58 is attached to the crankshaft 24 from the crankshaft 24. The cam chain 59 that transmits the power of the above is wound around.

The camshaft 48 is provided with an exhaust side cam 61, a low speed cam 62, and a high speed cam 63 that are arranged in order from the second support wall 53 toward the first support wall 52 side.

The exhaust side rocker arm 51 is arranged at a position corresponding to the exhaust side cam 61, and an intermediate portion of the exhaust side rocker arm 51 swings on an exhaust side rocker shaft 64 having an axis parallel to the cam shaft 48. Supported as possible. A roller 65 that rolls and contacts the exhaust-side cam 61 is supported at the end of the exhaust-side rocker arm 51 on the camshaft 48 side via a cylindrical support shaft 66. Further, the exhaust side rocker arm 51 is integrally provided with a pair of connecting arm portions 51a and 51b that are bifurcated so as to individually correspond to the pair of exhaust valves 42, and the connecting arm portions 51a and 51b are integrally provided. , The tappet screw 67 that abuts on the stem end 42a of both exhaust valves 42 is screwed so that the advancing / retreating position can be adjusted.

Moreover, the camshaft 48 includes the exhaust valve 42 of one of the pair of exhaust valves 42, and the operating axis CL of the exhaust valve 42 on the side of the pair of exhaust valves 42 closer to the second support wall 53 in this embodiment. As shown in FIG. 3, a virtual plane VP orthogonal to the roller 65 crosses the roller 65, and the relative positions of the one exhaust valve 42 and the roller 65 are set as such.

The intake side first rocker arm 49 is interlocked with and connected to the pair of the intake valves 41, and the intake side first rocker arm 49 is bifurcatedly connected to the pair of intake valve 41 sides. Arms 49a and 49b are integrally provided, and tappet screws 68 abutting on the stem ends 41a of the pair of intake valves 41 are screwed onto the connecting arms 49a and 49b so that the advancing / retreating positions can be adjusted. A roller 69 that rolls and contacts the low-speed cam 62 is rotatably supported at the end of the intake-side first rocker arm 49 on the camshaft 48 side via a cylindrical support shaft 70.

The intake-side second rocker arm 50 is arranged adjacent to the intake-side first rocker arm 49 so as to be free with respect to the pair of intake valves 41, and the cam of the intake-side second rocker arm 50. At the end on the shaft 48 side, a roller 71 that rolls and contacts the high-speed cam 63 provided on the cam shaft 48 is rotatably supported via a cylindrical support shaft 72.

The intermediate portion between the intake side first rocker arm 49 and the intake side second rocker arm 50 is swingably supported by an intake side rocker shaft 75 having an axis parallel to the cam shaft 48 and the exhaust side rocker shaft 64. .. As will be shown in FIG. 4, the exhaust side rocker shaft 64 is arranged below the cylinder axis C and in front of the camshaft 48 at the first and second support walls 52 and 53. The intake side rocker shaft 75 is supported and supported by the first and second support walls 52 and 53 so as to be arranged above the cylinder axis C and in front of the camshaft 48. Moreover, the second support wall 53 is engaged with a bolt 76 that engages with the exhaust side rocker shaft 64 to fix the exhaust side rocker shaft 64 to the second support wall 53 and engages with the intake side rocker shaft 75. A bolt 77 that fixes the intake side rocker shaft 75 to the second support wall 53 is screwed in.

By the way, the variable valve gear 47 has a connection position and a connection state in which the intake side first rocker arm 49 and the intake side second rocker arm 50 are connected to each other and supported by the intake side rocker shaft 75. The switching pin 78 is provided with a short columnar switching pin 78 that is urged toward the disconnection position side while allowing movement between the connection release positions, and a pressing force is applied to the switching pin 78 toward the connection position side. The solenoid 80 as an actuator having an output rod 79 that can come into contact with the switching pin 78 is a specific side wall of the side wall of the cylinder head 27 of the engine body 14, that is, the cylinder head in this embodiment. A plurality of mounting plates 82 fixed to the housing 81 of the solenoid 80 are mounted on the left side wall 27c of the 27 so as to be fastened with, for example, two bolts 83.

The intake side second rocker arm 50 is arranged between the intake side first rocker arm 49 and the left side wall 27c. Moreover, in order to prevent the roller 71 of the intake side second rocker arm 50 from separating from the high-speed cam 63 when the switching pin 78 is in the disconnection position, the cylinder head 27 of the engine body 14 is prevented. A spring 84, which is a torsion spring, is interposed between the second rocker arm 50 on the intake side. The spring 84 is arranged at a position between the intake side second rocker arm 50 and the left side wall 27c while overlapping with the output rod 79, as is clearly shown in FIG. 3, when viewed from the direction along the cylinder axis C. Will be done.

Focusing on FIG. 6, the intake-side second rocker arm 50 has a cylindrical support cylinder portion 50a extending to the side opposite to the intake-side first rocker arm 49 and surrounding the intake-side rocker shaft 75. The tip of the support cylinder portion 50a is integrally provided so as to be close to or in sliding contact with the left side wall 27c, and the spring 84 is arranged so as to surround the support cylinder portion 50a.

One end portion 84a of the spring 84 is inserted into the support shaft 72 of the intake side second rocker arm 50 and is engaged with the support shaft 72. On the other hand, the other end 84b of the spring 84 is engaged with the engine body 14 side, and in this embodiment, the other end portion 84b of the spring 84 is integrated with the upper portion of the first support wall 52 of the cylinder head 27 of the engine body 14. The other end portion 84b of the spring 84 is engaged with the boss portion 52a that is formed and through which the stud bolt 54 is inserted.

The intake side second rocker arm 50 is provided with a fitting hole 85 for slidably fitting the switching pin 78 so as to have an axis parallel to the camshaft 48, and the fitting hole 85 is provided. , The switching pin 78 at the disconnection position is formed so as to accommodate the entire length in the axial direction.

On the other hand, the intake side first rocker arm 49 has a bottomed connecting hole 86 having an axis parallel to the camshaft 48 and opening to the intake side second rocker arm 50 side, and a part of the switching pin 78 is provided. It is provided so that it can be slidably fitted. A bottomed cylindrical receiving member 87 connected to the switching pin 78 is slidably fitted in the connecting hole 86 so as to exert a spring force for urging the connecting pin 78 to the disconnection side. The return spring 88 provided between the receiving member 87 and the intake side first rocker arm 49 is housed in the connecting hole 86. Moreover, the fitting hole 85 and the connecting hole 86 are formed to have the same diameter with a circular cross-sectional shape so as to be coaxially connected at the timing when the intake valve 41 is in the closed state.

By pressing the switching pin 78 with the output rod 79 until a part of the switching pin 78 is fitted into the connecting hole 86 against the spring force of the return spring 88, the intake side first and second The rocker arms 49 and 50 are connected so that the pair of intake valves 41 open and close with operating characteristics corresponding to the cam profile of the high-speed cam 63. Further, by deactivating the solenoid 80, the contact surfaces of the switching pin 78 and the receiving member 87 are arranged between the intake side first and second rocker arms 49 and 50 by the spring force of the return spring 88. When the switching pin 78 and the receiving member 87 are moved in the axial direction until the switching pin 78 is moved, the connection between the first and second rocker arms 49 and 50 on the intake side is released, and in this state, the pair of the intake valves 41 opens and closes with operating characteristics corresponding to the cam profile of the low-speed cam 62.

The solenoid 80 can bring the output rod 79 into contact with the switching pin 78 from the side opposite to the receiving member 87, and apply a pressing force toward the connecting position side to the switching pin 78. The output rod 79 is formed to have a diameter smaller than that of the switching pin 78.

Further, the intake side second rocker arm 50 is formed with a notch recess 90 that exposes a part of the switching pin 78 to the outside. The notch recess 90 is formed in the intake side second rocker arm 50 so that the portion of the fitting hole 85 on the solenoid 80 side opposite to the intake side rocker shaft 75 is open. It is formed by notching the end on the solenoid 80 side, and the end on the solenoid 80 side of the remaining fitting holes 85 remaining without being notched regulates the disconnection position of the switching pin 78. The notch recess 90 is formed so as to form the regulation step portion 50a. Further, the end portion of the output rod 79 on the switching pin 78 side is arranged in the notch recess 90 as shown in FIG. 3 when viewed from the direction along the cylinder axis C.

Moreover, as shown in FIG. 6, the notch recess 90 is formed in the intake side second rocker arm 50 so as to open on the side opposite to the intake side rocker shaft 75, and has a smaller diameter than the switching pin 78. The axis C1 of the output rod 79 is set at a position offset from the axis C2 of the switching pin 78 to the side opposite to the intake side rocker shaft 75.

By the way, when the rotation speed of the camshaft 48 is equal to or less than a predetermined rotation speed, the exhaust valve 42 is slightly reduced by the decompression mechanism 91 so as to be in a decompression state in which the pressure of the combustion chamber 31 is reduced even in the compression stroke of the internal combustion engine E. It is driven to open the valve. The decompression mechanism 91 is arranged between the sprocket 58 fixed to the end of the camshaft 48 in the direction along the axis of the camshaft 48 and the exhaust side rocker arm 51. In the embodiment, the decompression mechanism 91 is arranged between the second support wall 53 located closer to the exhaust side rocker arm 51 than the sprocket 58 in the direction along the axis of the camshaft 48 and the exhaust side rocker arm 51. Will be done.

In FIG. 8, the decompression mechanism 91 rotates the decompression cam 92 from the decompression state to the decompression release state by a centrifugal force corresponding to the rotation speed of the camshaft 48 and the decompression cam 92 for decompressing the exhaust valve 42. It is a well-known conventional one including a decompression weight 93 to be driven and a torsion spring 94 for urging the decompression weight 93 in a closing direction approaching the camshaft 48.

The shaft portion 92a of the decompression cam 92 is rotatably supported on the side surface of the exhaust side cam 61, and the decompression weight 93 is placed on the side surface of the exhaust side cam 61 at a position where the cam shaft 48 is sandwiched between the shaft portion 92a. Is rotatably supported via the decompression pin 95, and the actuating pin 96 provided on the decompression weight 93 is inserted into a substantially U-shaped recess 97 formed in the decompression cam 92.

Next, the operation of this first embodiment will be described. It is possible to interlock and connect with a pair of intake valves 41 urged in the valve closing direction and to swing by following the low speed cam 62. The first rocker arm 49 on the intake side and the first rocker arm 49 on the intake side are arranged adjacent to the first rocker arm 49 on the intake side while allowing the intake valve 41 to be free and swinging in accordance with the high-speed cam 63. The intake side second rocker arm 50 is swingably supported by the intake side rocker shaft 75, and the connection position for connecting the intake side first rocker arm 49 and the intake side second rocker arm 50 and the above. A solenoid 80 having an output rod 79 that applies a pressing force toward the connection position side to the switching pin 78 that is urged toward the connection release position side while allowing movement between the connection release positions for releasing the connection state. Is attached to the left side wall 27c, which is a specific side wall of the cylinder head 27 of the engine body 14, and the intake side second rocker arm 50 is the intake side first rocker arm 49, the left side wall 27c, and the solenoid 80. A fitting hole 85 is provided in the intake side second rocker arm 50 so as to be arranged between the two, and the switching pin 78 is slidably fitted, and the fitting hole 85 is located at the disconnection position. It is formed so as to accommodate the total length of the switching pin 78 in the axial direction. Therefore, the intake side second rocker arm 50, which can be formed to be narrower than the intake side first rocker arm 49 by being free with respect to the intake valve 41, is interlocked with and connected to the intake valve 41. Since it is arranged between the side first rocker arm 49 and the solenoid 80, the fitting hole 85 provided in the intake side second rocker arm 50 accommodates the entire axial length of the switching pin 78 at the disconnection position. , The shaft length of the switching pin 78 can be shortened, the switching pin 78 can be prevented from tipping over to improve the supportability, and the frictional resistance when the switching pin 78 moves can be reduced to reduce the frictional resistance of the solenoid 80. It is possible to reduce the size.

Further, the spring 84 that urges the intake side second rocker arm 50 to rotate toward the high-speed cam 63 side overlaps with the output rod 79 when viewed from the direction along the cylinder axis C of the engine body 14, and the intake side second rocker arm 50. Since the spring 84 is arranged between the left side wall 27c and the left side wall 27c, the spring 84 is arranged by effectively utilizing the space between the solenoid 80 and the intake side second rocker arm 50, and the direction along the axis of the camshaft 48. The variable valve gear 47 can be miniaturized.

Further, a roller 71 that rolls and contacts the high-speed cam 63 is rotatably supported by the intake-side second rocker arm 50 via a cylindrical support shaft 72, and one end portion 84a of the spring 84 that is a torsion spring is described. Since it is inserted into the support shaft 72 and engaged with the support shaft 72, and the other end 84b of the spring 84 is engaged with the engine body 14 side, the roller 71 that rolls and contacts the high-speed cam 63 is rotated. One end 84a of the spring 84 is engaged with a simple structure using a cylindrical support shaft 72 provided on the second rocker arm so as to be freely supported, and one end 84a of the spring 84 is engaged. No special special member is required for this, and the number of parts can be reduced.

Moreover, since the other end 84b of the spring 84 is engaged with the boss portion 52a of the upper part of the first support wall 52 in the cylinder head 27 of the engine body 14, the other end 84b of the spring 84 is engaged. No special special member is required for fitting, and the number of parts can be reduced.

Further, since the notch recess 90 that exposes a part of the switching pin 78 to the outside is formed in the intake side second rocker arm 50, the inner surface of the fitting hole 85 of the intake side second rocker arm 50 and the switching pin 78. It is possible to easily guide the lubricating oil between the outer surfaces of the rocker arm.

Moreover, the notch recess 90 is formed at the end of the intake side second rocker arm 50 on the solenoid 80 side, and the end of the output rod 79 on the switching pin 78 side is viewed from the direction along the cylinder axis. Since it is arranged in the notch recess 90, the distance between the solenoid 80 and the intake side second rocker arm 50 can be shortened, and the variable valve gear 47 can be further miniaturized in the direction along the axis of the camshaft 48. it can.

Further, the notch recess 90 is formed in the intake side second rocker arm 50 so as to open to the side opposite to the intake side rocker shaft 75, and the axis C1 of the output rod 79 having a diameter smaller than that of the switching pin 78. However, since the axis C2 of the switching pin 78 is set at a position offset to the side opposite to the intake side rocker shaft 75, the output rod 79 swings around the axis of the intake side rocker shaft 75. 2 It is possible to secure a relatively large contact area between the output rod 79 and the switching pin 78, which have a small diameter, so that the switching pin 78 can be easily pressed while avoiding interference with the rocker arm 50.

Further, an exhaust side rocker shaft 64 having an axis parallel to the intake side rocker shaft 75 is supported by the cylinder head 27, interlocked with and connected to a pair of exhaust valves 42, and can be swung by the exhaust side rocker shaft 64. A roller 65 that rolls and contacts the exhaust side cam 61 provided on the camshaft 48 is rotatably supported by the exhaust side rocker arm 51 supported by the exhaust valve 42, and the operating axis of one of the pair of exhaust valves 42 is the exhaust valve 42. Since the relative positions of the specific exhaust valve 42 and the roller 65 are set so that the virtual plane VP orthogonal to the camshaft 48 including the camshaft 48 crosses the roller 65, the exhaust valve 42 and the exhaust side cam 61 It is possible to prevent the reaction force received by the exhaust side rocker arm 51 from being largely deviated in the direction along the axis of the exhaust side rocker shaft 64, and to prevent the exhaust side rocker arm 51 from being twisted.

Further, a sprocket 58 around which a cam chain 59 for transmitting power from the crankshaft 24 is wound around the cam shaft 48 is fixed to the end of the cam shaft 48, and the exhaust side is along the axis of the cam shaft 48. Since the decompression mechanism 91 is arranged between the rocker arm 51 and the sprocket 58, the decompression mechanism 91 can be arranged in a space-efficient manner.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes are made without departing from the present invention described in the claims. Is possible.

For example, in the above-described embodiment, the case where the engine valve is an intake valve 41 has been described, but the present invention can also be applied when the engine valve is an exhaust valve 42. Further, the actuator is not limited to the solenoid 80, and may have an output rod 79 that operates in the axial direction.

14 ... Engine body 27 ... Cylinder head 27c ... Left side wall 41 ... Engine valve Intake valve 47 ... Variable valve gear 48 ... Camshaft 49 ...・ Intake side first rocker arm 50 which is the first rocker arm ・ ・ ・ Intake side second rocker arm 62 which is the second rocker arm ・ ・ ・ Low speed cam 63 ・ ・ ・ High speed cam 71 ・ ・ ・ Roller 72 ・ ・ ・ Support shaft 75 ... Rocker shaft on the intake side Rocker shaft 78 ... Switching pin 79 ... Output rod 80 ... Actuator solenoid 84 ... Spring 84a ... Spring one end 84b ... Spring The other end 85 ... Fitting hole 90 ... Notch recess C ... Cylinder axis C1 ... Output rod axis C2 ... Switching pin axis

Claims (6)

A camshaft (48) having a low-speed cam (62) and a high-speed cam (63) is interlocked with and connected to an engine valve (41) urged in the valve closing direction, and is connected to the low-speed cam (62). The first rocker arm (49), which can be driven and swung, and the high-speed cam (63), which can be freed with respect to the engine valve (41), swing. The first rocker arm (49) and the first rocker arm (49) have an axis parallel to the camshaft (48) and the second rocker arm (50) arranged at a position adjacent to the first rocker arm (49). 2 A connection in which a rocker shaft (75) that commonly supports a rocker arm (50) on a cylinder head (27) of an engine body (14) and a first rocker arm (49) and a second rocker arm (50) are connected. A switching pin (78) that is urged toward the disconnection position side while allowing movement between the position and the connection release position that releases the connection state, and the switching pin (78) toward the connection position side. On a specific side wall (27c) of the side walls of the cylinder head (27) of the engine body (14) while having an output rod (79) that can come into contact with the switching pin (78) so as to apply the pressing force of In a variable valve device of an internal combustion engine including an actuator (80) to be attached and a spring (84) for rotating and urging the second rocker arm (50) toward the high-speed cam (63).
The second rocker arm (50) is arranged between the first rocker arm (49) and the specific side wall (27c), and is interposed between the engine body (14) and the second rocker arm (50). The spring (84) overlaps the output rod (79) when viewed from the direction along the cylinder axis (C) of the engine body (14), and is between the second rocker arm (50) and the specific side wall (27c). A variable valve gear for an internal combustion engine, characterized in that it is placed at an intervening position.
A roller (71) that rolls into contact with the high-speed cam (63) is rotatably supported by the second rocker arm (50) via a cylindrical support shaft (72), and is a torsion spring (84). ) Is inserted into the support shaft (72) and engaged with the support shaft (72), and the other end (84b) of the spring (84) is on the engine body (14) side. The variable valve gear of an internal combustion engine according to claim 1, wherein the valve gear is engaged with the internal combustion engine. The variable valve gear for an internal combustion engine according to claim 2, wherein the other end (84b) of the spring (84) is engaged with the cylinder head (27). The second rocker arm (50) is provided with a fitting hole (85) for slidably fitting the switching pin (78), and a notch for exposing a part of the switching pin (78) to the outside. The variable valve gear for an internal combustion engine according to any one of claims 1 to 3, wherein a recess (90) is formed. The notch recess (90) is formed at the end of the second rocker arm (50) on the actuator (80) side, and the end of the output rod (79) on the switching pin (78) side is the end. The variable valve gear for an internal combustion engine according to claim 4, wherein the variable valve gear of the internal combustion engine is arranged in the notch recess (90) when viewed from a direction along the cylinder axis (C). The output rod (90) is formed in the second rocker arm (50) so that the notch recess (90) opens on the side opposite to the rocker shaft (75), and has a diameter smaller than that of the switching pin (78). The fifth aspect of the present invention, wherein the axis (C1) of the 79) is set at a position offset from the axis (C2) of the switching pin (78) to the side opposite to the rocker shaft (75). Variable valve gear for internal combustion engines.

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