JP6546634B2 - Variable valve system for internal combustion engine - Google Patents

Description

  The present invention makes it possible to interlock with and connect to a cam shaft having a low speed cam and a high speed cam, and an intake valve urged in the valve closing direction, and to swing by following the low speed cam. Intake-side first rocker arm and intake-side disposed adjacent to the intake-side first rocker arm while being allowed to swing freely following the cam for high speed while enabling freedom with respect to the intake valve An intake-side rocker shaft having a second rocker arm, an axis parallel to the camshaft, and supporting the intake-side first rocker arm and the intake-side second rocker arm in common, the intake-side first rocker arm and the intake side Switching that is biased toward the connection release position while enabling movement between the connection position in which the second rocker arm is in the connection state and the connection release position in which the connection state is released Emissions and, relates to a variable valve device for an internal combustion engine and an actuator attached to the switching engine body of the cylinder head while having an output rod for applying a pressing force toward the connecting position side to the pin.

  An intake valve is interlocked and connected to the first rocker arm that can be driven by the low speed cam so that the second rocker arm and the first rocker arm that are driven by the high speed cam are rocked. It is switched by a solenoid attached to the side wall of the cylinder head, and switched between a state in which the intake valve is opened and closed in an operating characteristic corresponding to the cam profile of the low speed cam and a state in which an intake valve is opened and closed in an operating property corresponding to the cam profile of the high speed cam A variable valve system for an internal combustion engine which has been adapted for example is already known, for example, from U.S. Pat.

International Publication 2017/065168 Pamphlet

  In the variable valve system disclosed in Patent Document 1, the intake-side first rocker arm interlocked and coupled to the intake valve is disposed between the intake-side second rocker arm and the solenoid, and the switching pin is slidably fitted. A fitting hole is formed in the intake side first rocker arm. By the way, since the intake-side first rocker arm is interlocked and coupled to the intake valve, the width along the axis of the intake-side rocker shaft must be larger than that of the intake-side second rocker arm that can be free to the intake valve. As a result, the axial length of the switching pin slidably fitted to the intake side first rocker arm also becomes relatively long. Therefore, not only is the switching pin prone to fall when the pressing force from the solenoid acts on the switching pin, but the pressing force is increased with the increase of the frictional resistance at the time of movement of the switching pin. This leads to an increase in the size of the actuator.

  The present invention has been made in view of the above circumstances, and it is possible to shorten the length of the switching pin, to improve the supportability at the time of movement of the switching pin and to miniaturize the actuator. An object of the present invention is to provide an engine variable valve system.

In order to achieve the above object, according to the present invention, a cam shaft having a low speed cam and a high speed cam, and an intake valve which is urged in a valve closing direction is interlocked with and coupled with the low speed cam An intake-side first rocker arm capable of swinging, and a mechanism capable of swinging by following the cam for high speed while enabling freedom with respect to the intake valve, to the intake-side first rocker arm An intake side second rocker arm disposed adjacent to each other, an intake side rocker shaft having an axis parallel to the camshaft and commonly supporting the intake side first rocker arm and the intake side second rocker arm, and the intake side rocker shaft It is possible to move between the connection position where the side first rocker arm and the intake side second rocker arm are in the connection state, and the connection release position where the connection state is released. Variable movement of an internal combustion engine provided with a switching pin biased toward the position side and an actuator mounted on a cylinder head of the engine body while having an output rod for applying a pressing force to the switching pin toward the connection position side In the valve device, the intake side second rocker arm is disposed between the intake side first rocker arm and the actuator, and a fitting hole for slidably fitting the switching pin is provided in the intake side second rocker arm. The fitting hole is formed so as to accommodate the axial entire length of the switching pin at the connection release position, and the notch recess for exposing a part of the switching pin to the outside is the intake side second rocker arm wherein the end of the actuator side, are formed so as to face the combined cover to the cylinder head and the first, wherein Rukoto That.

Further, according to the present invention, a cam shaft having a low speed cam and a high speed cam, and an intake valve urged in the valve closing direction can be interlocked and connected, and can be oscillated following the low speed cam. Intake-side first rocker arm and intake air arranged adjacent to the intake-side first rocker arm while being allowed to pivot with the high-speed cam while enabling freedom with respect to the intake valve An intake side rocker shaft having a side second rocker arm, an axis parallel to the camshaft, and supporting the intake side first rocker arm and the intake side second rocker arm in common, the intake side first rocker arm and the intake side rocker shaft Disconnection biased toward the connection release position while enabling movement between the connection position where the side second rocker arm is in the connection state and the connection release position where the connection state is released A variable valve operating system for an internal combustion engine, comprising: a spur pin; and an output rod for applying a pressing force toward the connection position to the switching pin, and an actuator attached to a cylinder head of the engine body. A second rocker arm is disposed between the intake-side first rocker arm and the actuator, and a fitting hole for slidably fitting the switching pin is provided in the intake-side second rocker arm, and the fitting hole is A notch formed so as to accommodate the entire axial length of the switching pin at the connection release position and exposing a part of the switching pin to the outside is an end portion on the actuator side of the suction side second rocker arm And the end on the switching pin side of the output rod is formed so as to open on the side opposite to the intake side rocker shaft. The axis of the output rod, which is disposed in the recess and viewed from the direction along the cylinder axis of the main body and smaller in diameter than the switching pin, is on the opposite side of the axis of the switching pin to the intake side rocker shaft A second feature is to be set at an offset position.

The present invention, in addition to the first feature, the end of the switching pin side of the front SL output rod is disposed in the notch recess when viewed from a direction along the cylinder axis of the engine body As the third feature.

According to the present invention, in addition to the configuration of the third feature, the notch recess is formed in the intake second rocker arm so as to open on the opposite side to the intake rocker shaft, and the cutaway recess is formed more than the switching pin. A fourth feature is that the axis of the small-diameter output rod is set at a position offset from the axis of the switching pin on the opposite side to the intake-side rocker shaft.

In the present invention, in addition to any one of the configurations of the first to fourth features, an exhaust-side rocker shaft having an axis parallel to the intake-side rocker shaft is supported by the cylinder head and interlocked with a plurality of exhaust valves. A roller, which is in rolling contact with the exhaust side cam provided on the camshaft, is rotatably supported by the exhaust side rocker arm connected and rockably supported by the exhaust side rocker shaft. A fifth feature is that a relative position of the one exhaust valve and the roller is set such that a virtual plane orthogonal to the camshaft including the operating axis of the one exhaust valve intersects the roller. .

  The present invention, in addition to any of the configurations of the first to fifth features, further comprises a spring for rotationally urging the intake second rocker arm to the high speed cam side, wherein the spring is of the engine body. It is disposed at a position interposed between the intake second rocker arm and a specific side wall to which the actuator is attached among the side walls of the cylinder head while overlapping with the output rod as viewed from the direction along the cylinder axis. As the sixth feature.

  In the present invention, in addition to the configuration of the sixth feature, a roller in rolling contact with the cam for high speed is rotatably supported by the intake second rocker arm via a cylindrical support shaft, and is a torsion spring. A seventh feature is that one end of a certain 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.

Further, according to the present invention, in addition to the configuration of the fifth feature, a sprocket on which a cam chain transmitting power from a crankshaft is wound on the camshaft is fixed at an end of the camshaft. An eighth feature is that a decompression mechanism is disposed between the exhaust side rocker arm and the sprocket in a direction along an axis.

  The left side wall 27c of the embodiment corresponds to the specific side wall of the present invention, and the solenoid 80 of the embodiment corresponds to the actuator of the present invention.

According to the first aspect of the present invention, the intake-side second rocker arm, which can be formed freely with respect to the intake valve and can be formed narrower than the intake-side first rocker arm, is interlocked and coupled to the intake valve. The switching pin, which is disposed between the suction-side first rocker arm and the actuator, and in which the fitting hole provided on the suction-side second rocker arm so as to slidably fit the switching pin is in the coupling release position Since the axial length of the switching pin can be shortened, the axial length of the switching pin can be shortened, so that the switching pin can be prevented from falling to enhance supportability, and at the time of movement of the switching pin. The actuator can be miniaturized by reducing the frictional resistance. Moreover, the end of the switching pin on the actuator side of the intake side second rocker arm is exposed to the outside, so that the valve chamber is lubricated between the inner surface of the fitting hole of the intake side second rocker arm and the outer surface of the switching pin. It is possible to make it easy to guide oil.

According to the second feature of the present invention, in addition to the feature similar to the first feature, the notch on the actuator side of the intake side second rocker arm is formed with a notch and the end of the output rod on the switching pin side Since the part is in the notch and viewed from the direction along the cylinder axis, the distance between the actuator and the intake side second rocker arm is shortened, and the variable valve system is made in the direction along the camshaft and rocker shaft axes. It can be miniaturized. In addition, the notch recess is opened on the opposite side to the intake side rocker shaft and is formed on the intake side second rocker arm, and the axis of the output rod smaller in diameter than the switching pin is opposite to the axis of the switching pin and the intake side rocker shaft Since it is offset to the side, the contact area of the small diameter output rod and the switching pin can be reduced while avoiding the interference of the output rod with the intake second rocker arm swinging around the axis of the intake rocker shaft. A relatively large size can be ensured to make it easy to press the switching pin.

According to a third aspect of the present invention, the output end of the switching pin side of the rod as seen from the direction along the cylinder axis, the cutout recess formed at an end of the actuator side of the intake-side second rocker arm As a result, the distance between the actuator and the intake second rocker arm can be reduced, and the variable valve actuating device can be further miniaturized in the direction along the camshaft and rocker shaft axes.

According to the fourth feature of the present invention, the notch recess is opened on the opposite side to the intake side rocker shaft and is formed on the intake second rocker arm, and the axis of the output rod smaller in diameter than the switching pin is the switching pin Since the axis and the intake side rocker shaft are offset to the opposite side, the output rod has a small diameter while avoiding interference with the intake side second rocker arm swinging around the axis of the intake side rocker shaft. A relatively large contact area between the rod and the switching pin can be secured to facilitate pressing of the switching pin.

According to the fifth feature of the present invention, the roller in rolling contact with the exhaust side cam can rotate on the exhaust side rocker arm that is interlocked and connected with the plurality of exhaust valves and supported swingably by the exhaust side rocker shaft The virtual plane perpendicular to the cam shaft intersects the roller including the working axis of one of the exhaust valves, and the reaction force received by the exhaust rocker arm from the exhaust valve and the exhaust cam is on the exhaust side. A large displacement in the direction along the axis of the rocker shaft can be suppressed, and the occurrence of a twist in the exhaust side rocker arm can be suppressed.

  According to the sixth aspect of the present invention, the spring for rotationally urging the intake second rocker arm to the high speed cam side overlaps with the output rod when viewed from the direction along the cylinder axis, while the spring on the intake side second rocker arm Since the cylinder head is positioned between the side wall of the cylinder head and the specific side wall to which the actuator is attached, the cam is arranged by effectively utilizing the space between the actuator and the intake second rocker arm. The variable valve device can be miniaturized in the direction along the axis of the shaft.

  According to the seventh aspect of the present invention, the spring having a simple structure utilizing a cylindrical support shaft provided on the intake side second rocker arm so as to rotatably support the roller rollingly contacting the high speed cam Since the one end is engaged, a special dedicated member for engaging the one end of the spring is not necessary, and the number of parts can be reduced.

  According to the eighth feature of the present invention, since the decompression mechanism is disposed between the exhaust-side rocker arm and the sprocket provided at the end of the camshaft in the direction along the axis of the camshaft, the decompression mechanism can be a space. It can be arranged efficiently.

Fig. 2 is a left side view of the motorcycle. FIG. 1 is a left side view of an essential part of an internal combustion engine. FIG. 3 is a view taken along line 3-3 in FIG. It is line 4-4 in FIG. 3 sectional drawing. It is a perspective view which shows a cylinder head and a variable valve apparatus in the state from which the head cover was abbreviate | omitted. It is line 6-6 in FIG. 3 sectional drawing. 7 is a cross-sectional view taken along line 7-7 of FIG. It is line 8-8 in FIG. 7 sectional drawing.

  Embodiments of the present invention will be described with reference to the attached drawings. In the following description, upper, lower, right and left and front and rear refer to directions as viewed from a passenger on a motorcycle.

  First, in FIG. 1, a body frame F of a scooter type motorcycle has a front fork 11 for supporting a front wheel WF and a head pipe 13 for steeringably supporting a steering handle 12 connected to the front fork 11 at the front end. The power unit P, which exerts the power for driving the rear wheel WR, is supported by the vehicle body frame F in the front-rear direction middle portion so as to be capable of swinging up and down.

  The power unit P includes an internal combustion engine E disposed in front of the rear wheel WR, and a transmission M transmitting the output of the internal combustion engine E to the rear wheel WR. The transmission M is an engine body of the internal combustion engine E A rear cushion unit 16 is provided between a rear portion of the transmission case 15 and a rear portion of the vehicle body frame F.

The vehicle body frame F and a part of the power unit P are a vehicle body cover 17 having a pair of left and right footrests 18 on which a passenger's foot is placed and a floor tunnel 19 raised upward between the footrests 18. Covered, the body cover 17 is attached to the body frame F. Also the the floor tunnel portion occupant's seat 2 1 disposed behind the 19, and the passenger seat 2 2 which is arranged behind the passenger seat 2 1 is disposed on the body cover 17.

  Referring also to FIGS. 2 to 4, the engine body 14 of the internal combustion engine E has a crankcase 25 rotatably supporting 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 coupled to the crankcase 25; a cylinder head 27 coupled to the cylinder block 26; And a head cover 28 coupled to the cylinder head 27. The cylinder axis C of the engine body 14, that is, the axis of the cylinder bore 30 is slightly inclined forward and forward, and the piston 29 is connected to the crankshaft 24.

  An intake device 32 for supplying air to the combustion chamber 31 formed between the cylinder block 26 and the cylinder head 27 with the top of the piston 29 facing is located above the transmission case 15 on the left side of the rear wheel WR. , And a throttle body 34 disposed between the air cleaner 33 and the cylinder head 27. The fuel injection valve 35 includes the throttle body 34 and the cylinder. It is attached to the upper portion of the intake pipe 36 connecting between the upper side walls 27 a of the head 27.

  An exhaust device 38 for discharging exhaust gas from the combustion chamber 31 is connected to the lower side wall 27 b of the cylinder head 27. The exhaust device 38 is connected to the engine body 14 from the lower side wall 27 b of the cylinder head 27. And an exhaust muffler (not shown) disposed 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 a pair of intake valves 41 for performing intake control of the intake device 32 to the combustion chamber 31, and a pair of exhaust valves for performing exhaust control of the combustion chamber 31 to the exhaust device 38. The exhaust valve 42 and the intake valve 41 are disposed so as to be able to open and close, both intake valves 41 are biased in the valve closing direction by the valve spring 43, and both exhaust valves 42 are biased in the valve closing direction by the valve spring 44. Further, on the left side wall 27 c of the cylinder head 27 is mounted an ignition plug 45 which causes the end of the combustion chamber 31 to face.

  Referring to FIGS. 5 to 7 together, the valve operating chamber 46 formed between the cylinder head 27 and the head cover 28 changes the opening and closing operation characteristics of the intake valve 41 according to the engine speed. And a variable valve device 47 for driving the intake valve 41 and the exhaust valve 42 to open and close.

  The variable valve device 47 is shared by both the intake valves 41 and the two exhaust valves 42, and has a single camshaft 48 disposed between the two intake valves 41 and the two exhaust valves 42, both the intake valves 41 and the cams. The suction side first and second rocker arms 49 and 50 interposed between the shafts 48 and the single exhaust side rocker arm 51 interposed between both the exhaust valves 42 and the camshaft 48 are provided.

  The camshaft 48 has an axis parallel to the crankshaft 24, and is disposed at a position spaced apart in a direction along the axis of the camshaft 48 and integrally provided on the cylinder head 27. The first and second support walls 52 and 53 are rotatably supported. The first and second support walls 52 and 53 are formed to extend in a direction perpendicular 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 disposed at a position spaced inwardly from the right side wall 27 d of the cylinder head 27. Moreover, bosses 52a and 52b for inserting stud bolts 54 and 55 for connecting the cylinder block 26 and the cylinder head 27 to the crankcase 25 are provided at both longitudinal end portions, ie, upper and lower end portions of the first support wall 52. Bosses formed integrally with each other and inserting stud bolts 56 and 57 for connecting the cylinder block 26 and the cylinder head 27 to the crankcase 25 at both longitudinal end portions, ie, upper and lower end portions, of the second support wall 53 The portions 53a and 53b are integrally formed.

  A sprocket 58 is fixed to an end of the cam shaft 48 projecting from the second support wall 53 to the right side wall 27 d side of the cylinder head 27. The cam chain 59 for transmitting the power of the vehicle is wound.

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

  The exhaust side rocker arm 51 is disposed at a position corresponding to the exhaust side cam 61, and the middle portion of the exhaust side rocker arm 51 is swung by the exhaust side rocker shaft 64 having an axis parallel to the camshaft 48. Possible support. A roller 65 in rolling contact with the exhaust side cam 61 is supported by a cylindrical support shaft 66 at an end of the exhaust side rocker arm 51 on the camshaft 48 side. Further, the exhaust side rocker arm 51 is integrally provided with a pair of connecting arm portions 51a and 51b bifurcated so as to correspond individually to the pair of exhaust valves 42, and these connecting arm portions 51a and 51b are provided. A tappet screw 67 in contact with the stem end 42a of both exhaust valves 42 is screwed in such a manner that the advancing and retracting positions can be adjusted.

  In addition, the camshaft 48 includes the operating axis CL of one exhaust valve 42 of the pair of exhaust valves 42, in this embodiment, the exhaust valve 42 on the side closer to the second support wall 53 of the pair of exhaust valves 42. A virtual plane VP orthogonal to the above intersects the roller 65 as clearly shown in FIG. 3, and the relative position of the one exhaust valve 42 and the roller 65 is set as such.

  The intake-side first rocker arm 49 is interlocked and coupled to the pair of intake valves 41, and the intake-side first rocker arm 49 is bifurcated toward the pair of intake valves 41. The arm portions 49a and 49b are integrally provided, and tappet screws 68 in contact with the stem end 41a of the pair of intake valves 41 are respectively screwed on the connection arm portions 49a and 49b so that the advancing / retreating position can be adjusted. A roller 69 in rolling contact with the low speed cam 62 is rotatably supported via a cylindrical support shaft 70 at an end of the intake side first rocker arm 49 on the camshaft 48 side.

  The intake side second rocker arm 50 is disposed 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 cams of the intake side second rocker arm 50 are disposed. At an end portion on the shaft 48 side, a roller 71 rollingly in contact with the high speed cam 63 provided on the camshaft 48 is rotatably supported via a cylindrical support shaft 72.

  An 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 camshaft 48 and the exhaust side rocker shaft 64. . As clearly shown in FIG. 4, the exhaust-side rocker shaft 64 is disposed on the first and second support walls 52 and 53 so as to be disposed below the cylinder axis C and in front of the camshaft 48. The intake side rocker shaft 75 is supported by the first and second support walls 52 and 53 so as to be disposed above the cylinder axis C and in front of the camshaft 48. Moreover, the second support wall 53 is engaged with a bolt 76 engaging with the exhaust side rocker shaft 64 to fix the exhaust side rocker shaft 64 to the second support wall 53 and engaging with the intake side rocker shaft 75. A bolt 77 for fixing the intake side rocker shaft 75 to the second support wall 53 is screwed.

  By the way, the variable valve operating device 47 has a connecting position and a connecting state in which the intake side first rocker arm 49 and the intake side second rocker arm 50 supported by the intake side rocker shaft 75 adjacent to each other are connected. And a short cylindrical switching pin 78 biased toward the connection release position while enabling movement between the connection release positions, and pressing force of the switching pin 78 toward the connection position is provided. The solenoid 80 as an actuator having an output rod 79 which can abut the switching pin 78 in such a manner as to apply a specific side wall of the side wall of the cylinder head 27 of the engine body 14, in this embodiment the cylinder head On the left side wall 27c of the housing 27, a plurality of mounting plates 82 fixed to the housing 81 of the solenoid 80, for example, It is mounted so as to be fastened with a number of bolt 83.

  The intake side second rocker arm 50 is disposed 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 second rocker arm 50 from separating from the high speed cam 63 with the switching pin 78 in the connection release position, the cylinder head 27 of the engine body 14 is prevented. A spring 84, which is a torsion spring, is interposed between the intake side second rocker arm 50. The spring 84 is disposed at a position interposed between the intake second rocker arm 50 and the left side wall 27c while overlapping with the output rod 79 as clearly shown in FIG. 3 when viewed from the direction along the cylinder axis C. Be done.

  Focusing on FIG. 6, in the intake side second rocker arm 50, a cylindrical support cylindrical portion 50a extending to the opposite side to the intake side first rocker arm 49 and surrounding the intake side rocker shaft 75 is concerned. The distal end of the support cylindrical 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 disposed so as to surround the support cylindrical portion 50a.

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

  A fitting hole 85 for slidably fitting the switching pin 78 is provided in the intake side second rocker arm 50 so as to have an axis parallel to the camshaft 48, and the fitting hole 85 is provided. The axial length of the switching pin 78 located at the connection release position is accommodated.

  On the other hand, in the intake side first rocker arm 49, a bottomed connection hole 86 having an axis parallel to the camshaft 48 and opened to the intake side second rocker arm 50 side is a part of the switching pin 78. It is provided to be able to 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 urging the connecting pin 78 toward the connection release side. The return spring 88 provided between the receiving member 87 and the intake side first rocker arm 49 is accommodated in the connection hole 86. Moreover, the fitting hole 85 and the connecting hole 86 are formed coaxially in a circular cross-sectional shape and have the same diameter so as to be coaxially connected at the timing when the intake valve 41 is in the valve closing state.

  By pressing the switching pin 78 with the output rod 79 until the part of the switching pin 78 is fitted to the connection hole 86 against the spring force of the return spring 88, the first and second suction sides can be used. The rocker arms 49 and 50 are connected, whereby the pair of intake valves 41 open and close with the operation characteristic corresponding to the cam profile of the high speed cam 63. When the solenoid 80 is inactivated, the contact surfaces of the switching pin 78 and the receiving member 87 are disposed between the first and second suction 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 they are engaged, the connection of the intake side first and second rocker arms 49 and 50 is released, and in this state, the pair of intake valves 41 is opened and closed with an operating characteristic 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 connection position to the switching pin 78. The output rod 79 is smaller in diameter than the switching pin 78.

Further, the intake side second rocker arm 50 is formed with a cutout recess 90 for exposing a part of the switching pin 78 to the outside. The notch concave portion 90 is configured such that a portion on the opposite side of the suction side rocker shaft 75 in an approximately half portion on the solenoid 80 side of the fitting hole 85 is in an open state. The end on the side of the solenoid 80 is cut out, and the end on the side of the solenoid 80 among the remaining fitting holes 85 remaining without being cut restricts the connection release position of the switching pin 78 as a restricting step portion 50 b of the cutout recess 90 is formed. The end of the output rod 79 on the side of the switching pin 78 is disposed in the cutout recess 90 as clearly shown in FIG. 3 as viewed from the direction along the cylinder axis C.

  Moreover, as shown in FIG. 6, the notch concave portion 90 is formed in the intake second rocker arm 50 so as to open on the opposite side 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 offset from the axis C2 of the switching pin 78 on the opposite side to the intake side rocker shaft 75.

  By the way, the exhaust valve 42 is slightly decompressed by the decompression mechanism 91 so that the pressure in the combustion chamber 31 is reduced even in the compression stroke of the internal combustion engine E when the rotational speed of the camshaft 48 is less than a predetermined rotational speed. The valve is driven open. The decompression mechanism 91 is disposed between the sprocket 58 fixed to the end of the camshaft 48 in a direction along the axis of the camshaft 48 and the exhaust-side rocker arm 51, In the embodiment, the decompression mechanism 91 is disposed between the exhaust side rocker arm 51 and the second support wall 53 closer to the exhaust side rocker arm 51 than the sprocket 58 in the direction along the axis of the camshaft 48. Be done.

  In FIG. 8, the decompression mechanism 91 rotates the decompression cam 92 from the decompression state to the decompression release state by the decompression cam 92 for setting the exhaust valve 42 in the decompression state and the centrifugal force according to the rotational speed of the camshaft 48. It is known in the prior art to include a decompression weight 93 to be driven, and a torsion spring 94 to bias 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 mounted on the side surface of the exhaust side cam 61 at a position where the camshaft 48 is sandwiched with the shaft portion 92a. Is rotatably supported via a decompression pin 95, and an operating pin 96 provided on the decompression weight 93 is inserted into a substantially U-shaped recess 97 formed on the decompression cam 92.

To describe the operation of the implementation in the form of Tsuginiko, in conjunction with the pair of intake valves 41 is biased in the closing direction, made it possible to swing by following the low-speed cam 62 while being connected It is disposed adjacent to the suction side first rocker arm 49 while being allowed to swing along with the intake side first rocker arm 49 and the cam 63 for high speed while enabling freedom with respect to the intake valve 41. A second intake arm rocker arm 50 is swingably supported by the intake side rocker shaft 75, and a coupling position for bringing the intake first rocker arm 49 and the intake second rocker arm 50 into a coupling state and the coupling position An output rod 7 for applying a pressure toward the connection position side to the switching pin 78 biased toward the connection release position while allowing movement between the connection release positions for releasing the state A solenoid 80 having a valve mechanism is attached to the left side wall 27c which is a specific side wall of the cylinder head 27 of the engine main body 14. The intake side second rocker arm 50, the intake side first rocker arm 49, and the left side wall 27c and a solenoid 80, and the fitting hole 85 for slidably fitting the switching pin 78 is provided in the intake second rocker arm 50, and the fitting hole 85 is in the connection release position. It is formed so that the axial direction full length of the said switching pin 78 which exists in may be accommodated. 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 able to be free with respect to the intake valve 41, is interlocked with and coupled to the intake valve 41. Since it will be arranged between the side first rocker arm 49 and the solenoid 80, and the fitting hole 85 provided in the intake side second rocker arm 50 accommodates the entire axial length of the switching pin 78 located at the connection release position. It is possible to shorten the axial length of the switching pin 78, suppress the occurrence of falling of the switching pin 78 to enhance supportability, and reduce the frictional resistance at the time of movement of the switching pin 78 to reduce Miniaturization can be achieved.

  Further, a spring 84 for rotationally urging the intake second rocker arm 50 to the high speed cam 63 side overlaps the output rod 79 when seen from the direction along the cylinder axis C of the engine body 14 while the intake second rocker arm 50 And the left side wall 27c, the spring 84 is disposed 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 Thus, the variable valve device 47 can be miniaturized.

A roller 71 in rolling contact with 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 84a of the spring 84, which is a torsion spring, is Since the other end 84 b of the spring 84 is engaged with the side of the engine main body 14 by being inserted into the support shaft 72 and engaged with the support shaft 72, the roller 71 in rolling contact with the high speed cam 63 is rotated. One end 84a of the spring 84 is engaged with a simple structure using the cylindrical support shaft 72 provided on the intake side second rocker arm 50 so as to be freely supported, and one end 84a of the spring 84 The need for a special dedicated member for engaging the connector can reduce the number of parts.

  Moreover, since the other end 84b of the spring 84 is engaged with the boss 52a of the upper portion of the first support wall 52 of the cylinder head 27 of the engine body 14, the other end 84b of the spring 84 is engaged. A special dedicated member for fitting is not necessary, and the number of parts can be reduced.

Further, since the notch concave portion 90 for exposing a part of the switching pin 78 in the external valve operating chamber 46 is formed in the intake second rocker arm 50, the fitting hole 85 of the intake second rocker arm 50 is formed. Lubricating oil can be easily introduced between the inner surface and the outer surface of the switching pin 78.

  Moreover, the notch concave portion 90 is formed at the end of the intake 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. Is disposed in the notch recess 90, so that the distance between the solenoid 80 and the intake second rocker arm 50 can be shortened, and the variable valve actuating device 47 can be further miniaturized in the direction along the axis of the camshaft 48. it can.

  Further, the notch concave portion 90 is formed in the intake second rocker arm 50 so as to open on the opposite side to the intake side rocker shaft 75, and the axis C1 of the output rod 79 smaller in diameter than the switching pin 78. Is set to a position offset from the axis C2 of the switching pin 78 to the opposite side to the intake side rocker shaft 75, the output rod 79 swings around the axis of the intake side rocker shaft 75. The contact area between the small diameter output rod 79 and the switching pin 78 can be secured relatively large while avoiding interference with the two rocker arms 50, and the switching pin 78 can be easily pressed.

  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 and interlocked with and connected to a pair of exhaust valves 42 and rockable by the exhaust-side rocker shaft 64 The roller 65 in rolling contact with the exhaust side cam 61 provided on the camshaft 48 is rotatably supported by the exhaust side rocker arm 51 supported on the operating axis of one of the pair of exhaust valves 42. Since the relative position of the specific exhaust valve 42 and the roller 65 is set such that a virtual plane VP orthogonal to the camshaft 48 including the above intersects the roller 65, the exhaust valve 42 and the exhaust side cam 61 The reaction force received by the exhaust-side rocker arm 51 is prevented from being largely deviated in the direction along the axis of the exhaust-side rocker shaft 64, It is possible to suppress the serial of twist occurs in the exhaust-side rocker arm 51.

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

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various design change is made, without deviating from this invention described in the claim. Is possible.

  For example, the actuator is not limited to the solenoid 80, but may have an axially acting output rod 79.

14 · · · Engine body 24 · · · Crankshaft 27 · · · Cylinder head 27c · · · · · Specific side wall left side wall
28 · · · Head cover 41 · · · Intake valve 42 · · · Exhaust valve 47 · · · · · variable valve system 48 · · · camshaft 49 · · · intake side first rocker arm 50 · · · intake side second rocker arm 51 ... Exhaust side rocker arm 58 ... Sprocket 59 ... Cam chain 61 ... Exhaust side cam 62 ... Low speed cam 63 ... High speed cam 64 ... Exhaust side rocker shaft 65, 71 · · · Rollers 72 · · · Support shaft 75 · · · Intake side rocker shaft 78 · · · switching pin 79 · · · output rod 80 · · · · · · · · · · as the actuator solenoid 84 ... spring 84a ... one end of the spring 84b ... the other end 85 of the spring ... fitting hole 90 ... notch recess 91 ... decompression mechanism C ... cylinder axis C1 ... axis C2 of the output rod ... Actuation axis VP · · · virtual plane of the axis CL · · · exhaust valve instead pins

Claims (8)

The cam shaft (48) having the low speed cam (62) and the high speed cam (63) and an intake valve (41) biased in the valve closing direction are interlocked with and connected to the low speed cam (62) An intake-side first rocker arm (49) which can be driven and oscillated, and allowing it to be free with respect to the intake valve (41) while being driven and oscillated by the high speed cam (63) An intake side second rocker arm (50) disposed adjacent to the intake side first rocker arm (49) so as to move, and an axis parallel to the camshaft (48), the intake side first An intake-side rocker shaft (75) commonly supporting the rocker arm (49) and the intake-side second rocker arm (50), and the intake-side first rocker arm (49) and the intake-side second rocker arm (50) connected And a switching pin (78) biased toward the coupling release position while enabling movement between the coupling position and the coupling release position for releasing the coupling state, and the coupling position to the switching pin (78) A variable valve device for an internal combustion engine, comprising: an actuator (80) mounted on a cylinder head (27) of an engine body (14) while having an output rod (79) for applying a pressing force toward the side;
The intake hole second rocker arm (50) is disposed between the intake side first rocker arm (49) and the actuator (80), and a fitting hole (85 for slidably fitting the switching pin (78)). Is provided in the intake-side second rocker arm (50), and the fitting hole (85) is formed so as to accommodate the entire axial length of the switching pin (78) in the connection release position ,
In the cylinder head (27), at the end on the actuator (80) side of the intake second rocker arm (50), a notch recess (90) exposing a part of the switching pin (78) to the outside variable valve apparatus of the combined cover (28) and is formed manner facing an internal combustion engine according to claim Rukoto. The cam shaft (48) having the low speed cam (62) and the high speed cam (63) and an intake valve (41) biased in the valve closing direction are interlocked with and connected to the low speed cam (62) An intake-side first rocker arm (49) which can be driven and oscillated, and allowing it to be free with respect to the intake valve (41) while being driven and oscillated by the high speed cam (63) An intake side second rocker arm (50) disposed adjacent to the intake side first rocker arm (49) so as to move, and an axis parallel to the camshaft (48), the intake side first An intake-side rocker shaft (75) commonly supporting the rocker arm (49) and the intake-side second rocker arm (50), and the intake-side first rocker arm (49) and the intake-side second rocker arm (50) connected And a switching pin (78) biased toward the connection release position while enabling movement between the connection position and the connection release position for releasing the connection state, and the connection position side to the switching pin (78) A variable valve device for an internal combustion engine, comprising: an actuator (80) mounted on a cylinder head (27) of an engine body (14) while having an output rod (79) for applying a pressing force toward the
The intake hole second rocker arm (50) is disposed between the intake side first rocker arm (49) and the actuator (80), and a fitting hole (85 for slidably fitting the switching pin (78)). Is provided in the intake-side second rocker arm (50), and the fitting hole (85) is formed so as to accommodate the entire axial length of the switching pin (78) in the connection release position,
The notch concave portion (90) for exposing a part of the switching pin (78) to the outside is provided at the end portion on the actuator (80) side of the intake second rocker arm (50) at the intake side rocker shaft (75). And the end portion on the switching pin (78) side of the output rod (79) is viewed from the direction along the cylinder axis (C) of the engine body (14). Axis (C1) of the output rod (79) disposed in the notch recess (90) and smaller in diameter than the switching pin (78) is the axis (C2) of the switching pin (78) intake side rocker shaft (75) variable valve system for an internal combustion engine, characterized in Rukoto set at a position offset on the opposite side of the. End of the switching pin (78) side of the front SL output rod (79) is disposed in the cutout recess (90) when viewed from a direction along the cylinder axis (C) of the engine body (14) variable valve device for an internal combustion engine according to claim 1, characterized in that. The notch recess (90) is formed in the intake second rocker arm (50) so as to open on the opposite side to the intake 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) on the opposite side to the suction side rocker shaft (75). The variable valve apparatus for an internal combustion engine according to claim 3 . 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 plurality of exhaust valves (42), and the exhaust side A roller (65) in rolling contact with the exhaust side cam (61) provided on the cam shaft (48) is rotatably supported by the exhaust side rocker arm (51) supported swingably by the rocker shaft (64) An imaginary plane (VP) perpendicular to the camshaft (48), including the operating axis (CL) of the exhaust valve (42) of one of the plurality of exhaust valves (42), crossing the roller (65) The variable valve device for an internal combustion engine according to any one of claims 1 to 4, wherein the relative position of the one exhaust valve (42) and the roller (65) is set.   The intake side second rocker arm (50) is provided with a spring (84) for urging the second rocker arm (50) to the high speed cam (63) side, and the spring (84) is a cylinder axis (C) of the engine body (14). And a specific side wall (27c) of the side wall of the cylinder head (27) to which the actuator (80) is attached while overlapping the output rod (79) as viewed from the direction The variable valve device for an internal combustion engine according to any one of claims 1 to 5, which is disposed at a position interposed therebetween.   A roller (71) in rolling contact with the high speed cam (63) is rotatably supported on the intake side second rocker arm (50) via a cylindrical support shaft (72), and is a torsion spring One end (84a) of the 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 the engine main body ( 14) The variable valve operating device for an internal combustion engine according to claim 6, characterized in that it is engaged on the side. A sprocket (58) on which a cam chain (59) for transmitting power from the crankshaft (24) is wound around the camshaft (48) is fixed at an end of the camshaft (48). 6. A variable valve operating system for an internal combustion engine according to claim 5 , characterized in that a decompression mechanism (91) is disposed between said exhaust side rocker arm (51) and said sprocket (58) in a direction along the axis of 48). .