JP2004011437A - Forcibly air-cooled engine for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forcibly air-cooled engine for a motorcycle having an engine body using as part of components a cylinder head, which has an almost horizontal cylinder axis and on at least one of right and left side faces of which a spark plug is mounted, borne on a body frame in a vertically rocking manner, the cylinder head being covered with a shroud forming a distribution passage for distributing forcibly cooling air between the cylinder head and itself, increasing the degree of freedom in arrangement of a high-tension cord and improving the bending durability of the high-tension cord. <P>SOLUTION: An ignition coil 126 to be arranged behind the cylinder head is supported by one of a pair of right and left rear frame members 29, 30 of the body frame 25. The high-tension cord 123 having one end ranging over the ignition coil 126 has the other end turned around into an approximately U-shape frontward to backward of a plug cap 121 to be connected to the spark plug and connected to the plug cap 121. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, there is provided an engine body having a cylinder axis substantially horizontal and having a cylinder head having a spark plug attached to at least one of left and right sides as a part of a component, the engine body being supported on a body frame so as to be vertically swingable, The present invention relates to a forced air-cooled engine for a motorcycle, in which at least a cylinder head of a main body is covered with a shroud that forms a flow passage through which air for forced air cooling flows with the cylinder head.
[0002]
[Prior art]
Conventionally, in a forced air-cooled engine for a motorcycle disclosed in Japanese Patent Application Laid-Open No. 9-144520, a shroud has a wall for regulating a plug cap so as to face the outside of a vehicle body.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional device, when the distance between the plug cap and a frame member of the vehicle body frame that is arranged outside the plug cap is small, the high tension connected to the plug cap facing the outside of the vehicle body is provided. It is difficult to arrange the cords, and it is necessary to arrange the high tension cords so as to be bent with a small bending radius. Therefore, it is difficult to improve the bending durability of the high tension cords.
[0004]
The present invention has been made in view of such circumstances, and has an increased degree of freedom in arranging a high tension cord, and can contribute to an improvement in bending durability of the high tension cord. The purpose is to provide.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is characterized in that an engine body having a cylinder head which is substantially horizontal and has a cylinder head to which a spark plug is mounted on at least one of the left and right sides as a part of a vehicle body is provided. A forced air cooling system for a motorcycle, which is supported by a frame so as to be able to swing up and down, and at least a cylinder head of the engine body is covered with a shroud that forms a flow passage between the cylinder head and the air passage for forced air cooling. In the engine, an ignition coil arranged behind the cylinder head is supported on one of a pair of left and right rear frame members provided in the vehicle body frame, and the other end of a high tension cord having one end connected to the ignition coil, From the front to the back of the plug cap connected to the spark plug It is folded in a U-shape, characterized in that it is connected to the plug cap.
[0006]
According to the configuration of the first aspect of the present invention, the high tension cord connected to the plug cap is extended forward from the plug cap, so that the plug cap and the plug cap of the body frame are formed. Even if the interval between the frame members arranged outside is small, it is possible to avoid the interference with the vehicle body frame and increase the degree of freedom in arranging the high tension cords, and also, the bending radius of the high tension cords Can be set relatively large to improve the durability of the high tension cord.
[0007]
According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a pair of upper and lower covers, which are mutually coupled so as to cover the cylinder head in a cooperative manner, are provided. A fitting hole for fitting the plug cap is formed between the mating surfaces of the two cover members, and the upper cover member covers a fitting portion of the plug cap into the fitting hole from above. An eaves are provided integrally, and the plug cap, which is urged to one side around the axis of the spark plug by an elastic force acting from the high tension cord, receives the plug cap against the elastic force. According to this structure, the plug cap is provided on the detent positioning portion formed on the eave, and the plug cap is positioned on the detent positioning portion formed on the eaves. The abutment and engagement by the elastic force acting from the Yong cord prevent the plug cap from rotating around the axis of the spark plug during engine operation, thereby preventing the vibration of the high tension cord. However, it is possible to effectively prevent the high tension cord from contacting other parts. In addition, since the fitting portion of the plug cap into the fitting hole is covered from above by the eaves, muddy water and the like falling on the members above the engine body do not adhere to the connection portion between the high tension cord and the plug cap. Can be
[0008]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, a clamp for holding a high tension cord connected to the plug cap is formed on the upper cover member so as to be continuous with the eaves. According to this structure, the high tension cord is held in the vicinity of the plug cap, whereby the vibration of the high tension cord can be more effectively prevented. The seat can increase the strength of the eaves.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described based on an embodiment of the present invention shown in the attached drawings.
[0010]
1 to 17 show one embodiment of the present invention. FIG. 1 is a side view of a scooter type motorcycle, and FIG. 2 is an intermediate portion of the scooter type motorcycle in a state where a body cover and a storage box are omitted. 3 is an enlarged sectional view taken along line 3-3 of FIG. 1, FIG. 4 is a view taken along arrow 4 in FIG. 3, FIG. 5 is a view taken along arrow 5 in FIG. 3, and FIG. 6 is a sectional view taken along line 6-6 in FIG. FIG. 7, FIG. 7 is a view of the head cover viewed from the cylinder head side, FIG. 8 is a sectional view taken along line 8-8 of FIG. 7, FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG. 11 is a sectional view taken along line 11-11 of FIG. 4, FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 5, FIG. 13 is a sectional view taken along line 13-13 of FIG. 5, and FIG. 14 is an enlarged sectional view taken along line 14-14, FIG. 15 is a sectional view taken along line 15-15 in FIG. 14, FIG. 16 is a sectional view taken along line 16-16 in FIG. 14, and FIG. It is.
[0011]
1 and 2, a scooter-type motorcycle body frame 25 includes a main frame pipe 27 having a front end to which a head pipe 26 is fixed, and a cross pipe 28 fixed to a rear end of the main frame pipe 27 at right angles. And a pair of right and left rear frame members 29 and 30 having front ends connected to both ends of the cross pipe 28, respectively.
[0012]
The main frame pipe 27 is composed of a down frame 27a inclined downward and backward from the head pipe 26, and a lower frame 27b extending substantially horizontally and rearward from the rear end of the down frame 27a. The pair of left and right rear frame pipes 29, 30 are formed by rising frame portions 29a, 30a extending rearward from both ends of the cross pipe 28, and extending substantially horizontally rearward from the rear ends of the rising frame portions 29a, 30a. At the same time, upper frame portions 29b and 30b which are curved in a horizontal plane so that the rear end openings face each other are integrally connected.
[0013]
A front fork 31 that straddles the front wheel WF is steerably supported on the head pipe 26, and a steering handle 32 is connected to an upper end of the front fork 31.
[0014]
At the front of the rear frame pipes 29 and 30 in the body frame 25, the front of the power unit P is supported so as to be able to swing up and down via a link mechanism 33, and is disposed on the rear right side of the power unit P. The rear wheel WR is pivotally supported at the rear of the power unit P.
[0015]
3 to 6, a power unit P includes an engine E which is a four-cycle forced air-cooled single cylinder disposed in front of a rear wheel WR, and a continuously variable transmission provided between the engine E and the rear wheel WR. M.
[0016]
The engine body 34 of the engine E includes a crankcase 35, a cylinder block 36 connected to the crankcase 35, a cylinder head 37 connected to the cylinder block 36 on the opposite side to the crankcase 35, and an opposite side to the cylinder block 36. And a head cover 38 coupled to the cylinder head 37. The head cover 38 is disposed between the two rear frame pipes 29, 30 of the body frame 25. The cylinder head 37 is a rise frame 29a of the both rear frame pipes 29, 30. , 30a.
[0017]
The cylinder block 36 is arranged such that the axis of a cylinder bore 39 provided in the cylinder block 36, that is, the cylinder axis C is slightly horizontal as the front is raised in the front-rear direction of the motorcycle. And a piston 40 slidably fitted in the cylinder bore 39 to form a combustion chamber 41. The piston 40 is connected via a connecting rod 42 and a crank pin 43 to a crankshaft 44 having a rotation axis parallel to the rotation axis of the rear wheel WR.
[0018]
The crankshaft 44 is rotatably supported by a crankcase 35 including a pair of case portions 35a and 35b which are connected to a plane including the cylinder axis C and orthogonal to the axis of the crankshaft 44. The shaft 44 has a first ball bearing 45 interposed between one case member 35 a and the crankshaft 44, and a second ball bearing 46 interposed between the other case member 35 b and the crankshaft 44.
[0019]
An intake port 47 that can communicate with the combustion chamber 41 is provided on an upper side surface of the cylinder head 37, and an exhaust port 48 that can communicate with the combustion chamber 41 is provided on a lower side surface of the cylinder head 37. An intake valve 49 and an exhaust valve 50 that open and close the intake port 47 and the exhaust port 48, respectively, are arranged on the cylinder head 37 so as to be substantially V-shaped on a plane projected on a plane perpendicular to the rotation axis of the crankshaft 44. And are spring-biased in a direction to close the intake port 47 and the exhaust port 48, respectively. A spark plug 51 facing the combustion chamber 41 is attached to at least one of the left and right side surfaces of the cylinder head 37, in this embodiment, to the right side surface in a state of facing forward in the traveling direction of the motorcycle.
[0020]
A valve mechanism 52 for opening and closing the intake valve 49 and the exhaust valve 50 is housed between the cylinder head 37 and the head cover 38. The valve mechanism 52 has an axis parallel to the axis of the crankshaft 44. A camshaft 55 rotatably supported by the cylinder head 37 and having intake and exhaust cams 53 and 54; an intake side supported by the cylinder head 37 with an axis parallel to the camshaft 55; Exhaust-side rocker shafts 56 and 57; an intake-side rocker arm 58 swingably supported by the intake-side rocker shaft 56 so as to drive the intake valve 49 following the intake cam 53; The exhaust-side rocker arm 5 swingably supported by the exhaust-side rocker shaft 57 so as to open and close the exhaust valve 50 following the exhaust valve 50. Provided with a door.
[0021]
A driven sprocket 60 is fixed to one end of the camshaft 55. On the other hand, a driving sprocket 61 is fixed at a position corresponding to the driven sprocket 60 on the outside of the second ball bearing 46 on the crankshaft 44, and the driving and driven sprockets 61 and 60 have endless cams. The chain 62 is wound around, and the cam chain 62 is movably stored in a storage chamber 63 formed over the cylinder block 36, the cylinder head 37, and the head cover 38. By the driving sprocket 61, the driven sprocket 60, and the cam chain 62, the camshaft 55 is driven to rotate at half the rotation speed of the crankshaft 44.
[0022]
A drive gear 64 is fixed to the crankshaft 44 on the outer side of the first ball bearing 45, and pumps oil through an oil strainer 79 from an oil storage section 65 formed at a lower portion in the crankcase 35. The oil pump 66 attached to the crankcase 35 is driven by the drive gear 64.
[0023]
A part of the oil discharged from the oil pump 66 is used for lubricating the valve mechanism 52, and the crankcase 35, the cylinder block 36, the cylinder head 37 and the head cover 38 An oil supply passage 67 for guiding oil to the valve mechanism 52 is provided. Moreover, in the cylinder head 37, the oil supply passage 67 is arranged at a position closer to the intake port 47 than the exhaust port 48. In this embodiment, the oil supply passage 67 is projected on a plane orthogonal to the axis of the crankshaft 44. An oil supply passage 67 is arranged at a position crossing the intake port 47.
[0024]
7 and 8, the downstream end of the oil supply passage 67 is connected to the coupling surface of the head cover 38 to the cylinder head 37 such that the oil from the cylinder head 37 side is supplied to one end. A flow groove 68 is provided, and a bottomed flow hole 69 is formed in the side wall of the head cover 38 so as to be continuous with the other end of the flow groove 68. The oil is ejected toward the valve mechanism 52 and provided on the inner surface of the side wall of the head cover 38.
[0025]
The head cover 38 is provided with a bottomed detection hole 71 connected to one end of the flow groove 68, and a mounting boss 72 projecting outward from the outer surface of the head cover 38 at a position corresponding to the detection hole 71. A temperature detector 73 is attached to the attachment boss 72 such that the detection element portion 73a projects into the detection hole 71. That is, the temperature detector 73 is attached to the head cover 38 of the engine body 34 such that the detection element 73a faces the oil supply passage 67.
[0026]
Referring to FIG. 3, a stator 74 fixed to the crankcase 35 and an outer rotor 75 fixed to the crankshaft 44 so as to surround the stator 74 are provided outside the drive gear 64. A generator 77 is provided, and a fan 77 is fixed to the crankshaft 44 outside the generator 76. The fan 77 has a plurality of blades 77b, 77b,... Integrally provided on an outer peripheral portion of a base 77a fastened to the outer rotor 75 of the generator 76 with a plurality of, for example, four bolts 78, 78,. is there.
[0027]
At least the cylinder block 36 and the cylinder head 37 of the engine body 34, a part of the crankcase 35 in this embodiment, the cylinder block 36 and the cylinder head 37 are covered with a shroud 82, and are formed between the engine body 34 and the shroud 82. The forced air cooling air discharged from the fan 77 flows through the flowing passage 81. Further, a plurality of cooling fins 36a,..., 37a are provided on the outer surfaces of the cylinder block 36 and the cylinder head 37 in order to enable efficient cooling by the cooling air flowing through the flow passage 81.
[0028]
The shroud 82 cooperates to cover the cylinder block 36 and the cylinder head 37 and is connected to each other so as to cover a pair of upper and lower cover members 83 and 84. The upper cover member 83, the lower cover member 84, and the fan cover 85 are each formed of a synthetic resin.
[0029]
The upper cover member 83 is provided with a plurality of engaging claws 87 projecting from the mating surface 86 with the lower cover member 84 toward the lower cover member 84. The lower cover member 84 has the engaging claws 87. Are provided. The upper and lower cover members 83, 84 are integrally provided with a plurality of fastened portions 89, 90, 90, which are in contact with each other on a mating surface 86, respectively. Are mutually fastened by screw members 91.
[0030]
In this manner, the upper and lower cover members 83, 84 are mutually reciprocated by the resilient engagement of the engaging claws 87 with the locking portions 88 and the fastening of the fastened portions 89, 90 with the screw members 91. As a result, the head cover 38 projects forward from the upper and lower cover members 83 and 84.
[0031]
The fan cover 85 is fastened to the case member 35a so as to cover the case member 35a, which is a part of the crankcase 35, and the fan 77. A plurality of screw members 92... 84.
[0032]
The fan cover 85 is provided with a suction tube 94 which forms a suction port 93 for sucking air from the outside toward the fan 77 side so as to correspond to the fan 77 on the outside. A louver 95 is provided in the suction port 93.
[0033]
The louver 95 includes a plurality of, for example, five ring portions 95a to 94d concentrically arranged with the suction tube 94, and a plurality of connecting portions 95e extending radially and connecting the connecting tube 94 and each of the ring portions 95a to 95d. A triangular timing mark 96 for adjusting the phase of the crankshaft 44 is written on the outer surface of the fan cover 85 at a position corresponding to one of the connecting portions 95e. The timing mark 96 is for adjusting the ignition timing, for example, and a plurality of, for example, four, for fixing the fan 77 to the crankshaft 44 is connected to the connecting portion 95e of the louver 95 corresponding to the timing mark 96. If one of the bolts 78 matches, the phase of the ignition timing can be easily adjusted.
[0034]
The timing mark 96 can be used not only for ignition timing adjustment but also for TDC and BDC timing adjustment, and the valve operating mechanism 52 can change the operation characteristics of at least one of the intake valve 49 and the exhaust valve 50. In this case, it can be used for adjusting the timing of changing the operation characteristics.
[0035]
9 and 10, a flat mounting surface 97 having an intake port 47 opened is provided on the upper side surface of the cylinder head 37, and the mounting surface 97 is provided with an inlet pipe 98. The downstream end is fastened with the insulator 99 interposed.
[0036]
A flange 98a is integrally provided at the downstream end of the inlet pipe 98, and the insulator 99 having the intake hole 100 communicating with the intake port 47 and the mounting surface 97 have shapes corresponding to the flange 98a. It is formed.
[0037]
Gaskets 101 and 102 surrounding the intake hole 100 endlessly are mounted on both surfaces of the insulator 99, and one gasket 101 is provided between the insulator 99 and the mounting surface 97, and between the insulator 99 and the flange portion 98a. Is provided with a gasket 102. Moreover, the thickness T of the insulator 99 is set to be larger than the distance S between the mounting surface 97 and the upper cover member 83 of the shroud 82.
[0038]
Bottom screw holes 103, 103 are provided on the mounting surface 97 on both sides of the intake port 47, and bolts 104, 104 inserted into the flange 98a and the insulator 99 are screwed into the screw holes 103, 103. Then, by tightening the bolts 104, 104, the inlet pipe 98 is fastened to the mounting surface 97 via the insulator 99.
[0039]
The upper cover member 83 of the shroud 82 that covers the cylinder head 37 is provided with an opening 105 into which the insulator 99 is fitted and positioned. The opening 105 is formed larger than the insulator 99 as shown in FIG. 10, and between the partial side surface of the opening portion 105 and the partial side surface of the insulator 99, the cooling air flowing through the flow passage 81 is provided. An air outlet 106 for discharging air to the outside is formed.
[0040]
An upstream end of the inlet pipe 98 is connected to a downstream end of a carburetor 108 disposed behind the inlet pipe 98 via a connection hose 107. An upstream end of the carburetor 108 is connected to a rear wheel WR. It is connected to an air cleaner 110 arranged on the left side via a connecting tube 109.
[0041]
11, a carburetor 108 is provided with a motorcycle starter 111 that is energized and controlled based on the value detected by the temperature detector 73. The motorcycle starter 111 is provided with a throttle valve (not shown) provided in the carburetor 108. ) Is attached to the carburetor body 112 so as to open and close the middle of the starting mixture passage 113 provided in the carburetor body 112 of the carburetor 108 so as to bypass the carburetor.
[0042]
A bleed pipe 114 is fixed to the carburetor main body 112 so as to be interposed at a portion of the starting air-fuel mixture passage 113 upstream of the motorcycle starter 111, and a fuel for causing the lower part of the bleed pipe 114 to protrude upward. The nozzle 115 is fixed to a lower portion of the vaporizer main body 112. A fuel case 116 for storing fuel is fixed to a lower portion of the carburetor main body 112, and a lower portion of the fuel nozzle 115 protrudes into the fuel in the fuel case 116.
[0043]
The motorcycle starter 111 has a needle valve 118 which is inserted into a nozzle 117 provided on the way downstream of the bleed pipe 114 in the middle of the starting air-fuel mixture passage 113 so as to be able to advance and retreat. Is determined by the energization control of the motorcycle starter 111, and thereby the amount of the starting air-fuel mixture flowing through the starting air-fuel mixture passage 113 is determined.
[0044]
A fitting hole 120 is formed between the mating surfaces 86 of the upper and lower cover members 83 and 84 that constitute a part of the shroud 82. The plug cap 121 connected to the ignition plug 51 has a flange 121a that contacts the outer surfaces of the upper and lower cover members 83 and 84 around the fitting hole 120 and fits into the fitting hole 101. Is done.
[0045]
The upper cover member 83 of the upper and lower cover members 83 and 84 is integrally provided with an eave 122 that covers the fitting portion of the plug cap 121 into the fitting hole 120 from above. As shown in FIG. 12, a detent positioning portion 122a is formed to abut and engage the plug cap 121 to prevent the plug cap 121 from rotating around the axis of the spark plug 51.
[0046]
The eaves 122 cover, from above, a fitting portion of the plug cap 121 into the fitting hole 120 which has a posture in which at least a part of the high tension cord 123 connected to the plug cap 121 extends forward from the plug cap 121. The detent positioning portion 122a is configured to move the plug cap 122, which is urged to one side around the axis of the ignition plug 51 by the elastic force acting from the high tension cord 123, to the elastic force. It is formed on the eave 122 so as to receive it against it.
[0047]
13, the upper cover member 83 is integrally formed with a clamp mounting seat 125 that is continuous with the eaves 122. The clamp 124 that is resiliently mounted on the clamp mounting seat 125 is formed. Thus, the high tension cord 123 connected to the plug cap 121 is held.
[0048]
The engine body 34 is supported by the body frame 25 such that the cylinder head 37 is disposed between the lower portions of the front rise frame portions 29a, 30a of the pair of left and right rear frame pipes 29, 30. An ignition coil 126 is also provided between the lower portions of the two rise frame portions 29a, 30a, and above the right rise frame portion 30a, which is one of the two rise frame portions 29a, 30a, as clearly shown in FIG. Supported.
[0049]
The other end of the high tension cord 123, one end of which is connected to the ignition coil 126, is folded back from the front to the rear of the plug cap 121 engaged with the detent positioning portion 122 a in a substantially U-shape to form the plug cap 121. Will be connected to
[0050]
14 to 17, the upper cover member 83 of the shroud 82 has engaging projections 128a, 128a protruding to the side closer to each other at its distal end, and the upper cover member 83 is opposed to each other. A pair of hooks 128, 128 rising from the outer surface of the cover member 83 and a pair of connecting walls 129, 130 rising from the outer surface of the upper cover member 83 facing each other while connecting the hooks 128, 128 are integrally formed. At the same time, a rectangular quadrangular through hole 131 surrounded by the hooks 128, 128 and the connecting walls 129, 130 is provided.
[0051]
A plurality of flexible elongate parts which are stacked on each other and pushed between the hooks 128, 128 are sandwiched between the engaging projections 128a, 128a of the hooks 128, 128 and the connecting walls 129, 130. In this embodiment, the cable 133, which is a flexible long part on the inner side, received by the two connecting walls 129, 130, and the outer surface where the two engaging projections 128a, 128a contact the outer surface. The tube 134, which is a flexible long part on the one side, is sandwiched between the engagement projections 128a, 128a and both connecting walls 129, 130.
[0052]
The cable 133 has a soft vinyl film and is connected to the temperature detector 73. The tube 134 made of a hard elastic material is connected to the head cover 38 for guiding the breather gas.
[0053]
Moreover, the hook 128 is connected to the board portion 128b whose base end is continuous with the upper cover member 83 over the entire length thereof, and to the board portion 128b at a plurality of places, for example, two places spaced apart in the longitudinal direction of the cable 133 and the tube 134. The distal end portion includes a plurality of, for example, two branch plate portions 128c, 128c on which the engaging protrusions 128a protrude, and a reinforcing wall 132 for receiving the cable 133 between the connecting walls 129, 130 is provided at each branch plate portion. The two hooks 128 are provided between the two hooks 128c.
[0054]
An exhaust pipe 118 is connected to the lower side surface of the cylinder head 37 that is not covered with the shroud 82 so as to connect the upstream end to the exhaust port 48, and the exhaust pipe 118 is disposed on the right side of the rear wheel WR. The downstream end of the exhaust pipe 118 is connected to the muffler 119.
[0055]
Paying particular attention to FIGS. 3 and 4, a transmission case 136 is connected to the crankcase 35 and extends to the left of the rear wheel WR in a state facing forward in the traveling direction of the motorcycle. The transmission case 136 is formed integrally with the case member 35 b of the crankcase 35 and extends rearward. A first transmission chamber 140 is formed between the case main body 137 and the case main body 137. It comprises a left cover 138 fastened to the main body 137 from the left side, and a right cover 139 which forms the second transmission chamber 141 between the case main body 137 and is fastened to the right rear of the case main body 137.
[0056]
At the front of the case main body 137 of the transmission case 136, a support arm 142 is provided so as to project from the side of the cylinder block 36 of the engine E. The support arm 142 is attached to the body frame 25. Is swingably supported via a link mechanism 33.
[0057]
The axle 143 of the rear wheel WR is rotatably supported by the rear part of the case body 137 and the right cover 139 of the transmission case 136. As shown in FIG. 1, a rear cushion 144 is provided between a rear portion of the case main body 137 and an upper frame portion 29 a of the rear frame pipe 29 of the body frame 25.
[0058]
The continuously variable transmission M is a V-belt type housed in the first transmission chamber 140, and a reduction gear train 145 is provided between the continuously variable transmission mechanism M and the axle 143.
[0059]
The continuously variable transmission mechanism M has a drive-side transmission pulley 146 connected to the end of the crankshaft 44 outside the second ball bearing 46, a rear portion of the case main body 137 having an axis parallel to the crankshaft 44, and A driven transmission pulley 149 mounted on a driven shaft 147 rotatably supported by the right cover 139 via a centrifugal clutch 148, and an endless V-belt 150 wound around the transmission pulleys 146 and 149.
[0060]
The drive-side transmission pulley 146 includes a fixed pulley half 146a fixed to the crankshaft 44, and a movable pulley half 146b mounted on the crankshaft 44 so as to be slidable in the axial direction. A V-shaped annular groove 151 is formed between the two pulley halves 146a and 146b, and the V belt 150 is inserted into the annular groove 151. A ramp plate 152 is fixed to the crankshaft 44 on the back side of the movable pulley half 146a, and a plurality of weight rollers 153 are accommodated between the movable pulley half 146a and the ramp plate 152 in a floating state. When the rotation speed of the crankshaft 44 increases, the weight roller 153 receiving the centrifugal force moves outward in the radial direction of the crankshaft 44 to bring the movable pulley half 146a closer to the fixed pulley half 146b. Thereby, the contact radius of the V-belt 150 to both pulley halves 146a and 146b increases.
[0061]
On the other hand, the driven transmission pulley 149 is connected to the driven shaft 147 via the centrifugal clutch 148 and is rotatably supported by the driven shaft 147, and a fixed pulley half formed integrally with the support cylinder 154. Body 149a and a movable pulley half 149b supported by the support cylinder 154 so as to be able to approach and separate from the fixed pulley half 149a and spring-biased in a direction approaching the fixed pulley half 149a. The V-belt 150 is inserted into a V-shaped annular groove 155 formed between the halves 149a and 149b. Thus, the movable pulley half 149a is configured such that as the contact radius of the V-belt 150 with the drive-side transmission pulley 146 increases, the contact radius of the V-belt 150 with the driven-side transmission pulley 149 decreases. The body 149b moves in the axial direction, whereby a continuously variable transmission is performed between the crankshaft 44 and the driven shaft 147 according to the rotation of the crankshaft 44.
[0062]
A kick shaft 156 is rotatably supported on the left cover 138 of the transmission case 136, and a kick pedal 157 (see FIG. 1) is provided at an outer end of the kick shaft 156. On the inner side of the left cover 138, between the kick shaft 156 and the crankshaft 44, a kick-type starting device 158 capable of transmitting the power of the kick shaft 156 to the crankshaft 44 in accordance with the operation of depressing the kick pedal 157 is provided. Provided.
[0063]
The reduction gear train 94 is provided between the driven shaft 147 and the axle 143 and housed in the second transmission chamber 141. The rotational power of the driven shaft 147 in the continuously variable transmission M is reduced by the reduction gear train 94. And transmitted to the axle 143 of the rear wheel WR.
[0064]
Incidentally, a storage box 160 capable of storing a helmet or the like is supported between the front portions of the two rear frame pipes 29 and 30 in the body frame 25 so as to be disposed above the engine E. A fuel tank 161 is supported between the rear portions of the frame pipes 29, 30.
[0065]
In addition, at the front of the upper frame portion 29b of the left rear frame pipe 29 of the two rear frame pipes 29, 30, an air cleaner 162 for secondary air for purifying secondary air supplied to the exhaust port 48 of the engine E is provided. Is supported. The downstream end of the intake tube 163 is connected to the intake port of the secondary air air cleaner 162, and the upstream end of the intake tube 163 is connected to the upper part of the right rear frame pipe 30 of the two rear frame pipes 29, 30. It is inserted into the rear end of the frame part 30b.
[0066]
A secondary air control valve 164 provided between the engine E and the secondary air air cleaner 162 is supported by a stay 165 attached to an upper portion of the rise frame portion 29a of the left rear frame pipe 29.
[0067]
A connection pipe portion 166 communicating with the rise frame portion 29a is provided below the rise frame portion 29a in the left rear frame pipe 29, and guides cooling air from the continuously variable transmission M of the power unit P. 167 is connected to the connection pipe 166.
[0068]
The vehicle body frame 25 is covered with a vehicle body cover 168 made of synthetic resin. The vehicle body cover 168 has a leg shield 169 that covers the front of the driver's feet and a lower part of the leg shield 169 for placing the rider's feet. The vehicle includes a continuous step floor 170 and a side cover 171 connected to the step floor 170 and covering the rear portion of the vehicle body from both sides.
[0069]
A seat 172 is provided on the side cover 171 so as to open and close the storage box 160 and the fuel tank 161 from above.
[0070]
Next, the operation of this embodiment will be described. An oil pump 66 for pumping oil from an oil reservoir 65 in the crankcase 35 is attached to the crankcase 35 of the engine body 34 to lubricate the valve train 52. Supply passage 67 for leading oil for the oil supply is provided in the crankcase 35, the cylinder block 36, the cylinder head 37 and the head cover 38 in connection with the oil pump 66, and the temperature detector 73 supplies oil to the detection element 73a. It is attached to the engine body 34 so as to face the passage 67.
[0071]
By the way, the oil supply passage 67 for guiding the oil discharged from the oil pump 66 to lubricate the valve operating mechanism 52 is filled with oil regardless of the operating state and posture as long as the engine is operating. As described above, since the detection element 73a of the temperature detector 73 is disposed facing the oil supply passage 67, the engine temperature is accurately and constantly controlled while minimizing the change in the operating state and the attitude of the engine E as much as possible. The oil temperature can be detected quickly, and a complicated structure is not required for detecting the oil temperature with the temperature detector 73.
[0072]
In addition, since the oil supply passage 67 is located closer to the intake port 47 than the exhaust port 48 in the cylinder head 37, the engine temperature can be accurately controlled while being hardly affected by heat radiation from the outer surface of the engine body 34. And can be detected quickly.
[0073]
The engine E is of a forced air cooling type in which cooling fins 36a,... 37a for air cooling are provided on the cylinder block 36 and the cylinder head 37, and the temperature detector 73 is provided with air cooling fins. , 37a, can accurately detect the engine temperature without being disturbed by the cooling fins 36a, 37a, and also simplify the structure for mounting the temperature detector 73.
[0074]
In addition, a motorcycle starter 111, which is energized and controlled based on a value detected by the temperature detector 73, to a carburetor 108 connected to the intake port 47 so as to open and close a starting air-fuel mixture passage 113 provided in the carburetor 108. Since it is mounted, the air-fuel mixture supplied to the engine E at the time of starting can be optimized based on the engine temperature accurately detected by the temperature detector 73, and the warm-up performance of the engine E can be improved.
[0075]
Further, the cylinder block 36 and the cylinder head 37 are covered with a shroud 82 that forms a flow passage 81 through which air for forced air cooling flows is formed between the cylinder block 36 and the cylinder head 37, so that the cooling air forced to be blown is provided. By attaching the temperature detector 73 to the head cover 38 so as not to be affected by the wind, an accurate engine temperature can be detected in spite of the forced air cooling engine.
[0076]
On the upper side surface of the cylinder head 37, a flat mounting surface 97 having the intake port 47 opened is provided, and an inlet pipe 98 is fastened to the mounting surface 97 via an insulator 99. An opening 105 for fitting and positioning the insulator 99 is provided in the upper cover member 83 of the shroud 82.
[0077]
Therefore, the insulator 99 is positioned and held on the shroud 82 by being fitted into the opening 105, and the insulator 99 is screwed into the screw holes 103 provided on the mounting surface 97 of the cylinder head 37. Since the function of guiding the bolts 104 is performed, the bolts 104 can be easily screwed and tightened into the screw holes 103, and the assembling property can be improved.
[0078]
Further, since the air outlet 106 is formed between a part of the inner surface of the opening 105 provided in the upper cover member 83 made of synthetic resin and a part of the side surface of the insulator 99, the inlet pipe 98 is heated by the warm air discharged from the air outlet 106. The warm-up performance can be improved by warming. In addition, the mold portion for forming the opening 105 at the time of molding the upper cover member 83 is relatively large so as to include a portion corresponding to the air outlet 106 to increase the strength, thereby improving the life of the mold. Can be contributed to.
[0079]
Further, since the thickness T of the insulator is set to be larger than the interval between the mounting surface 97 and the shroud 82, the insulator 99 is fitted into the opening 105 so as to be pressed against the mounting surface 97, so that the insulator can be used during assembly. 99 can be prevented from dropping off from the shroud 82, and the assemblability can be further improved.
[0080]
The shroud 82 includes a pair of upper and lower cover members 83 and 84 which are coupled to each other so as to cooperatively cover the cylinder block 36 and the cylinder head 37, and are attached to the right side surface of the cylinder head 37. A fitting hole 120 for fitting a plug cap 121 connected to the ignition plug 51 is formed between the mating surfaces 86 of the cover members 83 and 84. Moreover, the upper cover member 83 is provided with a fitting portion into the fitting hole 120 of the plug cap 121 in a posture in which at least a part of the high tension cord 123 connected to the plug cap 121 is extended forward from the plug cap 121, from above. A cover eave 122 is provided integrally, and a plug cap 121 urged to one side around the axis of the ignition plug 51 by an elastic force acting from the high tension cord 123 holds the plug cap 121 against the elastic force. It is in contact with and engages with the detent positioning portion 122a formed on the eave 122 so as to receive it.
[0081]
Therefore, at least a part of the high tension cord 123 is extended forward from the plug cap 121, so that there is a gap between the plug cap 121 and the rear frame pipe 30 of the body frame 25 that is arranged outside the plug cap 121. Is small, the interference with the vehicle body frame 25 can be avoided to increase the degree of freedom in arranging the high tension cord 123, and even when the high tension cord 123 is bent, the bending radius can be increased. Can be set relatively large to improve the life of the high tension cord 123.
[0082]
Further, the plug cap 121 abuts and engages with the detent positioning portion 122a formed on the eave 122 by the resilient force acting from the high tension cord 123. Rotation about the axis can be prevented, whereby vibration of the high tension cord 123 can be prevented, and the high tension cord 123 can be effectively prevented from contacting other parts.
[0083]
Moreover, since the fitting portion of the plug cap 121 into the fitting hole 120 is covered from above by the eaves 122, muddy water or the like that falls on a member above the engine body 34, for example, the storage box 160, is prevented from falling by the high tension cord 123 It can be prevented from adhering to the connection portion of the plug cap 121.
[0084]
Further, since the clamp 124 holding the high tension cord 123 is attached to the clamp attachment seat 125 formed on the upper cover member 83 continuously to the eave 122, the high tension cord 123 is held near the plug cap 121. Thus, the vibration of the high tension cord 123 can be more effectively prevented, and the strength of the eave 122 can be increased by the clamp mounting seat 125.
[0085]
Further, in the engine body 34, the rear frame pipes 29, 30 are provided with the cylinder head 37 in the side view so as to correspond to the lower portions of the rise frame portions 29a, 30a which are provided with the rear frame pipes 29, 30 at the front and inclined upward and rearward. It is supported between the vehicle body frame 25 so as to be able to swing up and down, and one end thereof is connected to an ignition coil 126 supported by one of the rear frame pipes 29 and 30 behind the cylinder head 37. The other end of the tension cord 123 is folded back from the front to the rear of the plug cap 121 engaged with the rotation preventing positioning portion 122a in a substantially U-shape, and is connected to the plug cap 121.
[0086]
According to such an arrangement, the high tension cord 123 can be easily routed while avoiding interference with the body frame 25, and the bending durability of the high tension cord 123 is more reliably improved. Can be.
[0087]
The upper cover member 83 of the shroud 82 has a pair of hooks 128 rising from the outer surface of the upper cover member 83, having engaging projections 128a, 128a protruding toward the side close to each other at their distal ends. , 128 and a pair of connecting walls 129, 130 rising from the outer surface of the upper cover member 83 facing each other while connecting the hooks 128, 128, are integrally provided, and the hooks 128, 128 and A rectangular quadrangular through-hole 131 surrounded by the connecting walls 129 and 130 is provided.
[0088]
A cable 133 and a tube 134 that are stacked on each other and pushed between the hooks 128, 128 are sandwiched between the engaging projections 128a, 128a of the hooks 128, 128 and the connecting walls 129, 130.
[0089]
Therefore, at the time of molding the upper cover member 83 made of synthetic resin, the pair of hooks 128, 128 and the pair of connecting walls 129, 130 can be integrally formed with a simple mold structure without using a slide mold. The cable 133 and the tube 134 can be stably supported by the hooks 128, 128 and the connecting walls 129, 130 without using parts other than the upper cover member 83 provided, thereby reducing the number of parts and the number of assembly operations. Thus, the cable 133 and the tube 134 can be stably supported on the flat surface of the upper cover member 83.
[0090]
Moreover, the through-hole 131 is covered with the cable 133 and the tube 134 overlapping each other, so that the inside of the upper cover member 83, that is, the inside of the shroud 82 is not visible from the through-hole 131 while supporting the cable 133 and the tube 134. .
[0091]
That is, the through-hole 131 is covered with the cable 133 and the tube 134 that are laminated on each other, and stably maintains the cooling performance of the forced air-cooled engine E by preventing the cooling air from leaking from the shroud 82. In addition, since the cable 133 and the tube 134 can be supported by the shroud 82 and the cooling air can be prevented from leaking from the through-hole 131, dust is prevented from being ejected to the outer surface side of the shroud 82 to improve the appearance. Can be prevented from decreasing.
[0092]
The cable 133 has a soft vinyl film and is connected to the temperature detector 73, and the tube 134 is formed of a hard elastic material to guide the breather gas and is connected to the head cover 38. The vinyl film on the outer surface of the cable 133 is sufficiently brought into close contact with the connecting walls 129, 130, and the engaging projections 128a, 128a at the tips of the hooks 128, 128 are securely engaged with the outer surface of the tube 134. In this way, the cable 133 and the tube 134 can be supported more reliably.
[0093]
Moreover, the hook 128 is connected to the board portion 128b whose base end is continuous with the upper cover member 83 over the entire length thereof, and to the board portion 128b at a plurality of places, for example, two places spaced apart in the longitudinal direction of the cable 133 and the tube 134. The distal end portion includes a plurality of, for example, two branch plate portions 128c, 128c on which the engaging protrusions 128a protrude, and a reinforcing wall 132 for receiving the cable 133 between the connecting walls 129, 130 is provided at each branch plate portion. The two hooks 128 are provided between the two hooks 128c.
[0094]
Therefore, the cable 133 and the tube 134 can be supported more stably by receiving the inner cable 133 also by the reinforcing wall 132, and the strength of the hooks 128, 128 can be increased by the reinforcing wall 132. Can be.
[0095]
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 can be made without departing from the present invention described in the claims. It is.
[0096]
【The invention's effect】
As described above, according to the first aspect of the present invention, at least a part of the high tension cord is extended forward from the plug cap, so that the plug cap and the frame member arranged outside the plug cap are connected to each other. Even if the gap between them is narrow, it is possible to avoid the interference with the body frame and increase the degree of freedom of placing the high tension cord, and compare the bending radius even when bending the high tension cord The life of the high tension cord can be improved by setting the target length to be large. Also, since the plug cap resiliently contacts and engages with the detent positioning portion, it is possible to prevent the plug cap from rotating around the axis of the ignition plug during operation of the engine. Of the high tension cord can be effectively prevented from coming into contact with other parts. Moreover, since the fitting portion of the plug cap into the fitting hole is covered from above by the eaves, muddy water and the like falling on the members above the engine body do not adhere to the connection portion between the high tension cord and the plug cap. Can be
[0097]
According to the second aspect of the present invention, the vibration of the high tension cord can be more effectively prevented by holding the high tension cord by the clamp in the vicinity of the plug cap. Strength can be increased.
[0098]
Further, according to the third aspect of the present invention, the high tension cord can be easily routed while avoiding interference with the vehicle body frame, so that the bending durability of the high tension cord is more reliably improved. Can be.
[Brief description of the drawings]
FIG. 1 is a side view of a scooter type motorcycle.
FIG. 2 is an intermediate perspective view of the scooter type motorcycle in a state where a vehicle body cover and a storage box are omitted.
FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG.
FIG. 4 is a view on arrow 4 in FIG. 3;
FIG. 5 is a view as viewed in the direction of arrow 5 in FIG. 3;
FIG. 6 is a sectional view taken along line 6-6 in FIG. 3;
FIG. 7 is a view of the head cover as viewed from a cylinder head side.
8 is a sectional view taken along line 8-8 of FIG. 7;
FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG. 6;
FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;
FIG. 11 is a sectional view taken along line 11-11 of FIG. 4;
FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 5;
FIG. 13 is a sectional view taken along line 13-13 of FIG. 5;
FIG. 14 is an enlarged sectional view taken along line 14-14 of FIG. 2;
FIG. 15 is a sectional view taken along line 15-15 of FIG. 14;
FIG. 16 is a sectional view taken along line 16-16 of FIG. 14;
FIG. 17 is a sectional view taken along line 17-17 of FIG. 14;
[Explanation of symbols]
25 Body frame 29, 30 Rear frame pipe 34 as rear frame member Engine body 37 Cylinder head 51 Spark plug 81 Flow passage 82 Shroud 83 ... upper cover member 84 ... lower cover member 86 ... mating surface 101 ... fitting hole 121 ... plug cap 122 ... eave 122a ... detent positioning part 123 ... high Tension cord 124 ・ ・ ・ Clamp 125 ・ ・ ・ Clamp mounting seat 126 ・ ・ ・ Ignition coil C ・ ・ ・ Cylinder axis

Claims (3)

An engine body (34) having a cylinder head (37) having a cylinder axis (C) substantially horizontal and a spark plug (51) attached to at least one of the left and right sides as a part of a component is a vehicle body frame (25). And at least the cylinder head (37) of the engine body (34) forms a flow passage (81) through which the air for forced air cooling flows with the cylinder head (37). In a forced air-cooled engine for a motorcycle covered with a shroud (82), one of a pair of left and right rear frame members (29, 30) provided in the body frame (25) is provided rearward of the cylinder head (37). An ignition coil (126) to be arranged is supported, and one end of the ignition coil (126) is connected to the ignition coil (126). The other end of the cord (123) is folded back in a substantially U-shape from the front to the rear of the plug cap (121) connected to the spark plug (51) and is connected to the plug cap (121). A forced air-cooled engine for motorcycles characterized by the following. The shroud (82) includes a pair of upper and lower cover members (83, 84) that are coupled to each other so as to cooperatively cover the cylinder head (37). A fitting hole (120) for fitting is formed between the mating surfaces (86) of the two cover members (83, 84), and the upper cover member (83) has the fitting hole of the plug cap (121). An eave (122) that covers the fitting portion to the (120) from above is integrally provided, and is urged toward one side around the axis of the ignition plug (51) by the elastic force acting from the high intensity cord (123). The plug cap (121) to be abutted against the detent positioning portion (122a) formed on the eaves (122) so as to receive the plug cap (121) against the elastic force. Forced air cooling engine for a motorcycle according to claim 1, characterized in that is engaged. A clamp (124) for holding the high tension cord (123) is attached to a clamp attachment seat (125) formed on the upper cover member (83) continuously with the eaves (122). A forced air-cooled engine for a motorcycle according to claim 2.

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