CN1270075C - Air intake connecting structure of forced air-cooled engine - Google Patents

Abstract

The object of the present invention is to provide an air intake coupling structure for forced air cooling engine, which enhances the assembly of an air intake coupling structure of forced-air-cooling engine in which a mounting face is mounted on a cover shielding a cylinder head and defines an intake port, and an insulator is mounted on the mounting face and securely fixing an inlet pipe. The solution is that in the cover 82, openings 105 are defined for receiving and positioning the insulator 99.

Description

Intake connection structure of forced air-cooled engine

technical field

The present invention relates to an intake connection structure of a forced air-cooled engine. In the intake connection structure of the forced air-cooled engine, a mounting surface for opening an intake hole is provided on a cylinder head covered by a shroud. An intake pipe is connected to the mounting surface with a heat insulator interposed therebetween.

Background technique

Such a structure is conventionally known from, for example, Japanese Patent Application Laid-Open No. 11-108187.

In the air intake connection structure of the above-mentioned prior art forced air-cooled engine, the shield is provided with an insertion port through which the intake pipe is inserted, and the intake pipe is inserted into the inlet while maintaining the intake pipe and the heat insulator by fastening. The flange of the air pipe and the bolts on the heat shield are connected to the mounting surface of the cylinder head. Therefore, when the bolts are inserted into the flange and the heat insulator, the screw holes on the mounting surface side are hidden by the flange and the heat insulator, and the mountability is poor.

Contents of the invention

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an intake connection structure of a forced air-cooled engine with improved assemblability.

In order to achieve the above object, the intake connection structure of the forced air-cooled engine of the first technical solution of the present invention is provided with a mounting surface on which the intake hole is opened on the cylinder head covered by the shroud, and sandwiched between the mounting surface The heat insulator is connected to the intake pipe, and is characterized in that an opening for fitting and positioning the heat insulator is provided on the shield.

According to the intake connection structure of such a forced-air-cooled engine, the heat insulator is positioned and held on the shroud by being fitted in the opening, and the heat insulator acts as a guide screw coupled to the screw hole. The function of the bolt is that the screw hole is provided on the mounting surface of the cylinder head. Therefore, the screwing and fastening of the bolt to the screw hole are facilitated, and the assemblability can be improved.

In addition, the intake connection structure of the forced air-cooled engine according to the second aspect of the present invention is based on the invention of the above-mentioned first aspect, and is characterized in that it is provided on the above-mentioned shroud made of synthetic resin An air outlet is formed between a part of the inner surface of the opening and a part of the side surface of the heat insulator. According to such a configuration, the warm-up performance can be improved by heating the intake pipe with the hot air discharged from the air outlet, and it can be used in the heat shield. The mold portion for forming the opening during the molding of the cover is relatively enlarged, including the portion corresponding to the above-mentioned exhaust port, thereby increasing its strength, which contributes to an increase in the life of the mold.

The intake connection structure of the forced air-cooled engine according to the third technical aspect of the present invention is characterized in that, in addition to the composition of the invention of the second technical aspect, the thickness of the heat insulating member is set to be thicker than that of the above-mentioned installation. The distance between the surface and the above-mentioned shield is large, and according to this structure, by pressing it against the mounting surface to fit the heat insulator into the mounting portion, it is possible to prevent the heat insulator from falling off the shield during assembly. , can further improve the assemblability.

Description of drawings

Fig. 1 is a side view of a scooter-type motorcycle.

2 is a perspective view of the middle portion of the scooter-type motorcycle in a state where the body cover and the storage box are omitted.

Fig. 3 is an enlarged sectional view of 3-3 in Fig. 1 .

FIG. 4 is a 4-arrow view of FIG. 3 .

Fig. 5 is a 5-arrow view of Fig. 3 .

Fig. 6 is a sectional view along line 6-6 of Fig. 3 .

Fig. 7 is a view of the head cover viewed from the cylinder head side.

Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 7 .

Fig. 9 is an enlarged cross-sectional view of line 9-9 in 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 cross-sectional view of line 12-12 in Fig. 5 .

Fig. 13 is a sectional view taken along line 13-13 of Fig. 5 .

Fig. 14 is an enlarged cross-sectional view of line 14-14 in 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 .

Detailed ways

Hereinafter, an embodiment of the present invention will be described based on an example of the present invention shown in the drawings.

1 to 17 show an embodiment of the present invention. FIG. 1 is a side view of a scooter-type motorcycle, and FIG. 2 is a middle part of a scooter-type motorcycle without a body cover and a storage box. Perspective view, Fig. 3 is an enlarged sectional view of 3-3 of Fig. 1, Fig. 4 is a view of arrow 4 of Fig. 3, Fig. 5 is a view of arrow 5 of Fig. 3, Fig. 6 is a sectional view of 6-6 of Fig. 3, Fig. 7 is A view of the head cover viewed from the cylinder head side. Fig. 8 is the 8-8 sectional view of Fig. 7, Fig. 9 is the 9-9 enlarged sectional view of Fig. 6, Fig. 10 is the 10-10 sectional view of Fig. 9, Fig. 11 is the 11-11 sectional view of Fig. 4, Fig. 12 is the 12-12 enlarged sectional view of Fig. 5, Fig. 13 is the 13-13 sectional view of Fig. 5, Fig. 14 is the 14-14 enlarged sectional view of Fig. 2, Fig. 15 is the 15-15 sectional view of Fig. 14, Fig. 16 is a 16-16 sectional view of FIG. 14 , and FIG. 17 is a 17-17 sectional view of FIG. 14 .

First in Fig. 1 and Fig. 12, the vehicle frame 25 of small motorcycle has main frame tube 27, horizontal tube 28, rear frame tube 29,30, and this main frame tube 27 is fixed head tube 26 at its front end, and this The horizontal tube 28 is vertically fixed to the rear end of the main frame tube 27, and the rear frame tubes 29 and 30 are a pair of left and right rear frame members whose front ends are connected to both ends of the horizontal tube 28, respectively.

The main frame pipe 27 is formed by integrally connecting a down frame portion 27a, which is inclined backward from the head pipe 26, and a bottom frame portion 27b, which is formed from the rear end of the down frame portion 27a. Extends roughly horizontally to the rear. In addition, the left and right pair of rear frame pipes 29, 30 are formed by integrally connecting the rising frame parts 29a, 30a and the upper frame parts 29b, 30b. Extending upward, the upper frame parts 29b, 30b extend substantially horizontally rearward from the rear ends of the rising frame parts 29a, 30a, and are bent in a horizontal plane so that their rear end openings face each other.

A front fork 31 straddling 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 .

The front part of the two rear frame tubes 29, 30 in the vehicle frame 25 supports the front part of the power unit P in a swingable up and down manner through the link mechanism 33, and the rear wheel WR arranged on the rear right side of the power unit P is It is supported on the rear of the power unit P with a shaft.

In FIGS. 3 to 6, the power unit P is composed of an engine E and a continuously variable transmission M. The engine E is a forced air-cooled single-cylinder four-stroke engine arranged in front of the rear wheel WR. The continuously variable transmission M is set between the engine E and the aforementioned rear wheel WR.

The engine body 34 of the engine E has a crankcase 35, a cylinder block 36 bonded to the crankcase 35, a cylinder head 37 bonded to the cylinder block 36 on the side opposite to the crankcase 35, and a cylinder head 37 bonded to the cylinder block 36 on the opposite side. The head cover 38 on the cylinder head 37, the engine body 34 is arranged between the two rear frame pipes 29, 30 of the vehicle frame 25, and the cylinder head 37 is arranged on the rising frame part 29a which is the front part of the two rear frame pipes 29, 30 , Between the lower part of 30a.

The cylinder block 36 is arranged on the cylinder block 36 with the axis of the cylinder inner diameter 39 , that is, the cylinder axis C, slightly inclined forward and upward along the front-rear direction of the motorcycle, and is arranged substantially horizontally. A combustion chamber 41 is formed between pistons 40 fitted in the cylinder bore 39 . In addition, the piston 40 is connected to a crankshaft 44 having a rotation axis parallel to the rotation axis of the rear wheel WR via a connecting rod 42 and a crank pin 43 .

The crankshaft 44 is rotatably supported by a crankcase 35 composed of a pair of case parts 35a, 35b combined in a plane perpendicular to the axis of the crankshaft 44 while including the cylinder axis C described above. 44 A first ball bearing 45 is interposed between one case member 35 a and the crankshaft 44 , and a second ball bearing 46 is interposed between the other case member 35 b and the crankshaft 44 .

The upper side of the cylinder head 37 is provided with an intake hole 47 that can communicate with the above-mentioned combustion chamber 41 , and the lower side of the cylinder head 37 is provided with an exhaust hole 48 that can communicate with the above-mentioned combustion chamber 41 . The intake valve 49 and the exhaust valve 50 , which open and close the intake port 47 and the exhaust port 48 , respectively, are disposed in the cylinder in a substantially V-shape on a projected view projected on a plane perpendicular to the rotation axis of the crankshaft 44 . On the cover 37, it is spring-pressed to the direction of closing the air intake hole 47 and the exhaust hole 48, respectively. In addition, the spark plug 51 facing the combustion chamber 41 is mounted on at least one of the left and right side surfaces of the cylinder head 37, and is mounted on the right side in a state facing forward in the direction of travel of the motorcycle in this embodiment. on the side.

Between the cylinder head 37 and the head cover 38 is housed a valve train 52 for opening and closing the intake valve 49 and the exhaust valve 50. The valve train 52 has a camshaft 55, intake side and exhaust side rocker arms. Shafts 56, 57, intake-side rocker arm 58, and exhaust-side rocker arm 59; the camshaft 55 has an axis parallel to the axis of the crankshaft 44, is rotatably supported on the cylinder head 37, and has an intake and exhaust cams 53, 54; the intake side and exhaust side rocker shafts 56, 57 have axes parallel to the camshaft 55 and are supported on the cylinder head 37; the intake side rocker arm 58 is driven by The above-mentioned intake cam 53 drives the intake valve 49, and is supported on the intake-side rocker shaft 56 to swing freely; the exhaust-side rocker 59 is driven by the above-mentioned exhaust cam 54 to open and close the drive exhaust valve. The air valve 50 is supported on the exhaust side rocker shaft 57 in a freely swingable manner.

A driven sprocket 60 is fixed to one end of the camshaft 55 . In addition, on the crankshaft 44, a driving sprocket 61 is fixed at a position corresponding to the above-mentioned driven sprocket 60 on the outer side of the second ball bearing 46, and an endless cam chain is hung around the driving and driven sprockets 61, 60. 62 , the cam chain 62 is housed in a storage chamber 63 so as to be able to walk, and the storage chamber 63 is formed along the cylinder block 36 , the cylinder head 37 and the cover 38 . The camshaft 55 is rotationally driven by the driving sprocket 61 , the driven sprocket 60 and the cam chain 62 at a rotational speed of 1/2 of the rotational speed of the crankshaft 44 .

On the outer side of the first ball bearing 45, a drive gear 64 is fixed to the crankshaft 44, and an oil pump 66 that absorbs oil from an oil storage portion 65 formed in the lower part of the crankcase 35 through an oil filter 79 is installed in the crankcase. 35, the oil pump 66 is driven by the above-mentioned drive gear 64.

A part of the oil discharged from the oil pump 66 is used to lubricate the valve train 52, and the crankcase 35, the cylinder block 36, the cylinder head 37, and the cover 38 are provided with a valve for guiding the oil from the oil pump 66 to the valve train 52. The oil supply road 67. Furthermore, in the cylinder head 37, the oil supply passage 67 is arranged at a position closer to the intake hole 47 than the exhaust hole 48. , the oil supply passage 67 is arranged at a position intersecting with the intake hole 47 .

7 and 8 at the same time, the downstream end of the oil supply path 67 is composed of a flow groove 68 and a bottomed flow hole 69, and the flow groove 68 is provided on the cover in order to supply oil from the cylinder head 37 side to one end. On the joint surface of the cover 38 combined with the cylinder head 37, the above-mentioned flow hole 69 is connected to the other end of the above-mentioned flow groove 68 and is provided on the side wall of the cover 38, and the spray hole connected to the inner end of the flow hole 69 70 is provided on the inner surface of the side wall of the cover 38 for spraying oil toward the valve train 52 .

A bottomed detection hole 71 connected to one end of the flow groove 68 is provided on the cover 38, and a mounting protrusion 72 is integrally protruded at a position corresponding to the detection hole 71. The outer surface of the cover 38 protrudes outward, and a temperature detector 73 having a detection element portion 73 a protruding into the detection hole 71 is attached to the mounting boss portion 72 . That is, the temperature detector 73 is attached to the cover 38 of the engine body 34 so that the detection element portion 73 a faces the oil supply passage 67 .

Referring to Fig. 3, a generator 76 is disposed outside the above-mentioned drive gear 64, and the generator 76 has a stator 74 fixed on the crankcase 35 and an outer rotor 75 surrounding the stator 74 and fixed on the crankshaft 44. On the outside of the generator 76 , a fan 77 is fixed to the crankshaft 44 . The fan 77 is formed by integrally providing a plurality of blades 77b, 77b on the outer periphery of a base 77a fastened to the outer rotor 75 of the generator 76 by, for example, four bolts 78, 78....

At least the cylinder block 36 and the cylinder head 37 in the engine body 34, a part of the crankcase 35 in this embodiment, the cylinder block 36 and the cylinder head 37 are covered by the shroud 82, and the forced air cooling air discharged from the fan 77 It flows through the flow passage 81 formed between the engine body 34 and the shroud 82 . Furthermore, a plurality of cooling fans 36a..., 37a... are protrudingly provided on the outer surfaces of the cylinder block 36 and the cylinder head 37, respectively. The user can be efficiently cooled by the cooling air flowing through the above-mentioned flow path 81 .

The cover 82 is composed of a pair of upper and lower cover members 83, 84 and a fan cover 85. The upper and lower cover members 83, 84 are combined to cover the cylinder block 36 and the cylinder head 37. The fan cover 85 The upper cover member 83 , the lower cover member 84 , and the fan cover 85 are respectively formed of synthetic resin, combined with the two cover members 83 and 84 to cover a part of the crankcase 35 .

The upper cover member 83 is protrudingly provided with a plurality of engagement claws 87 . The member 84 is provided with locking portions 88 ... for elastically coupling the above-mentioned coupling claws 87 .... In addition, on the upper and lower cover members 83, 84, a plurality of connected parts 89..., 90... that are in contact with each other on the joint surface 86 are integrally provided respectively, and the connected parts 89..., 90... that are in contact with each other are connected by bolt members 91... interconnected.

Due to the elastic connection of the coupling claws 87 ... towards the locking part 88 ... and the connection of the connected parts 89 ..., 90 ... by the bolt members 91 ..., the upper and lower cover members 83, 84 are combined with each other, and the cover The cover 38 protrudes forward from the upper and lower cover members 83 , 84 .

The fan cover 85 is connected to the case member 35a, covers the case member 35a and the fan 77 which are a part of the crank case 35, and is connected to the upper and lower cover members 83, 84 by a plurality of bolt members 92....

On the outside of the fan cover 85, a suction cylinder 94 is provided corresponding to the fan 77. The suction cylinder 94 forms a suction port 93 for sucking air from the outside toward the fan 77 side, and a louver is provided on the suction port 93. Plate 95.

The louver 95 is composed of a plurality of, for example, five ring portions 95a to 95d arranged concentrically with the suction cylinder 94, and a plurality of connection portions 95e extending radially to connect the connection cylinder 94 and the ring portions 95a to 95d. , at a position corresponding to one of the plurality of connecting portions 95e..., a timing mark 96 in, for example, a triangular shape for correcting the phase of the crankshaft 44 is marked on the inner surface of the fan 85 . This timing mark 96 is used for correcting the timing of ignition, for example. On the connecting portion 95e corresponding to the timing mark 96 in the above-mentioned louver 95, a plurality of, for example, 4 points for fixing the fan 77 on the crankshaft 44 are overlapped. One of the bolts 78..., so that the phase correction of the ignition timing can be easily performed.

The above-mentioned timing mark 96 can be used not only for the timing of the ignition, but also for correcting the timing of TDC and BDC, and the valve train 52 is configured to change at least the intake valve 49 and the exhaust valve 50. When changing the operating characteristics of one side, it can also be used to correct the timing of the change of its operating characteristics.

Referring to Fig. 9 and Fig. 10 at the same time, on the upper side of the cylinder head 37, a flat mounting surface 97 is provided to open the air intake hole 47, and the air intake pipe 98 is connected to the air intake pipe 98 on the mounting surface 97 with a heat insulator 99 interposed therebetween. downstream end.

A flange portion 98a is integrally provided at the downstream end of the intake pipe 98, and the heat insulator 99 having the intake hole 100 communicating with the intake hole 47 and the mounting surface 97 have shapes corresponding to the flange portion 98a.

The gaskets 101, 102 annularly surrounding the above-mentioned air inlet 100 are installed on both sides of the heat insulating element 99, and a side gasket 101 is interposed between the heat insulating element 99 and the mounting surface 97, between the heat insulating element 99 and the mounting surface 97. A gasket 102 is interposed between the flange portions 98a. Furthermore, the thickness T of the heat insulator 99 is set to be larger than the space S between the mounting surface 97 and the upper cover member 83 in the shroud 82 .

On both sides of the air intake hole 47, bottomed screw holes 103, 103 are provided on the mounting surface 97, and the bolts 104, 104 passing through the flange 98a and the heat insulator 99 are screwed into the above-mentioned screw holes 103, 104. In 103 , by tightening the bolts 104 , 104 , the intake pipe 98 is connected to the installation surface 97 through the heat insulator 99 .

An opening 105 for fitting and positioning the above-mentioned heat insulator 99 is provided in the upper cover member 83 of the shroud 82 covering the cylinder head 37 . This opening 105 is larger than the heat insulator 99 as shown in FIG. Exhaust vents 106 on the outside.

The upstream end of the intake pipe 98 is connected to the downstream end of the carburetor 108 disposed behind the air intake pipe 98 through a connecting hose 107 , and the upstream end of the carburetor 108 is connected to the rear wheel WR through a connecting pipe 109 . On the air filter 110 on the left side.

In Fig. 11, a motorcycle starter 111 controlled by electricity according to the detection value of the above-mentioned temperature detector 73 is attached to the carburetor 108, and the motorcycle starter 111 is installed on the carburetor body 112 for opening and closing. The mixture gas passage 113 for starting is provided on the carburetor main body 112 of the carburetor 108 in the middle of the air-fuel mixture passage 113 so as to bypass a throttle valve (not shown) included in the carburetor 108 .

A discharge pipe 114 is fixed to the carburetor main body 112 in the starting mixture passage 113 , and the discharge pipe 114 is interposed at a portion upstream of the motorcycle starter 111 . A fuel passage 115 in which the lower portion of the discharge pipe 114 protrudes to the upper portion is fixed to the lower portion of the carburetor main body 112 . Also, a fuel tank 116 for storing fuel is fixed to the lower portion of the carburetor body 112 , and the lower portion of the fuel passage 115 protrudes into the fuel in the fuel tank 116 .

The motorcycle starter 111 has a needle valve 118 that is inserted into a nozzle 117 provided in the middle of the starting mixture passage 113 so as to be freely advanced and retreated on the downstream side of the discharge pipe 114. The position is determined by the energization control of the motorcycle starter 111 , thereby determining the amount of starting air-fuel mixture flowing through the starting air-fuel mixture passage 113 .

A fitting hole 120 is formed between joint surfaces 86 of the upper and lower cover members 83 , 84 constituting a part of the shroud 82 . A spark cap 121 connected to the spark plug 51 has a flange portion 121a in contact with the outer surfaces of the upper and lower cover members 83 , 84 around the fitting hole 120 , and the spark cap 121 is fitted into the fitting hole 120 .

In addition, a shielding edge 122 is integrally provided on the upper cover member 83 of the upper and lower cover members 83, 84, and the shielding edge 122 covers the fitting portion where the spark plug cap 121 is fitted toward the fitting hole 120 from above, as shown in FIG. As shown in 12, a detent positioning portion 122a is formed at the front end of the shroud 122. The detent positioning portion 122a prevents the spark plug cap 121 from winding around the spark plug 51 by making the spark plug cap 121 contact and combine with the front end of the shroud 122. axis rotation.

The shielding edge 122 covers the fitting portion of the plug cap 121 that is fitted into the fitting hole 120 from above. The anti-rotation positioning portion 122a is formed on the shielding edge 122 to receive the spark plug cap 121 that is tended to rotate around the axis of the spark plug 51 by the elastic force acting from the high voltage wire 123 against the elastic force acting from the high voltage wire 123 .

Referring to Fig. 13 at the same time, a clip mounting seat 125 that is continuously connected to the above-mentioned shielding edge 122 is integrally formed on the upper cover member 83, and is held by a clip 124 elastically mounted on the clip mounting seat 125. The high-voltage electric wire 123 connected with the above-mentioned spark plug cap 121.

The engine body 34 is supported on the vehicle frame 25, and the cylinder head 37 is arranged between the lower parts of the front rising frame parts 29a, 30a of the pair of left and right rear frame pipes 29, 30, and the above-mentioned spark plug cap 121 is also arranged on both sides. Between the lower parts of the rising frame parts 29a, 30a, an ignition coil 126 is supported on the upper part of the right rising frame part 30a, which is one of the rising frame parts 29a, 30a, as shown in Fig. 2 .

One end of the high voltage wire 123 connected to the ignition coil 126 and the other end is folded back in a substantially U shape from the front of the spark plug cap 121 combined with the anti-rotation positioning portion 122a and connected to the spark plug cap 121 .

Referring to Figures 14 to 17 at the same time, a pair of hooks 128, 128 and a pair of connecting walls 129, 130 are integrally provided on the upper cover member 83 in the shield 82. The coupling protrusions 128a, 128a protruding from the side of the upper cover member 83 stand up from the outside of the upper cover member 83 while facing each other. The outer surface of the cover member 83 stands up, and a rectangular through-hole 131 surrounded by the hooks 128 , 128 and the connecting walls 129 , 130 is provided in the upper cover member 83 .

A plurality of flexible long parts are sandwiched between the coupling protrusions 128a, 128a of the two hooks 128, 128 and the above-mentioned two connecting walls 129, 130, and the flexible long parts are stacked on each other and pressed into the above-mentioned two hooks 128, 128, in this embodiment, the cable 133 is the flexible length on the inner side supported by the two connecting walls 129, 130, and the flexible length on the outer side of the above-mentioned two coupling protrusions 128a, 128a is in contact with the outside. A tube 134 which is a member is sandwiched between the joint protrusions 128 a , 128 a and the two connecting walls 129 , 130 .

The cable 133 has a soft vinyl sheath and is connected to the temperature detector 73, and the tube 134 made of a hard elastic material is connected to the head cover 38 for guiding ventilation gas.

Moreover, the above-mentioned hook 128 is composed of a base plate portion 128b and a plurality of, for example, two branch plate portions 128c, 128c. The cable 133 and the tube 134 are connected to the base plate portion 128b at a plurality of places at intervals in the longitudinal direction, for example, two places, and the coupling convex portion 128a is protrudingly provided at the front end thereof. Between the branch plate parts 128c, 128c, a reinforcement wall 132 is provided to receive the cable 133 between the two connecting walls 129, 130 so as to straddle between the two hooks 128, 128.

The exhaust pipe 118 is connected to the lower side of the cylinder head 37 not covered by the above-mentioned shroud 82, and the upstream end of the exhaust pipe 118 is connected to the exhaust hole 48. 119 is connected to the downstream end of the exhaust pipe 118 .

Referring to FIGS. 3 and 4 in particular, a transmission case 136 is connected to the crankcase 35 , and the transmission case 136 protrudes to the left side of the rear wheel WR in a state facing the front of the motorcycle. The transmission case 136 is composed of a case main body 137, a left side cover 138, and a right side cover 139. The case main body 137 is integrally connected to the case member 35b of the crankcase 35 and extends rearward. The first transmission chamber 140 is formed between the above-mentioned box main body 137 and is connected to the box main body 137 from the left side. The above-mentioned right side cover 139 forms a second transmission chamber 141 between it and the above-mentioned box main body 137 and is connected to the box body. The right rear portion of the main body 137.

A support arm portion 142 is protruded from the front portion of the case main body 137 in the transmission case 136, and the support arm portion 142 is disposed on the side of the cylinder block 36 in the engine E, and the support arm portion 142 is swingable by the link mechanism 33. ground supported on the frame 25.

The axle 143 of the rear wheel WR is rotatably supported by the rear part of the case main body 137 of the transmission case 136 and the right side cover 139 . As shown in FIG. 1 , a rear bumper 144 is provided between the rear portion of the tank main body 137 and the upper frame portion 29 a in the rear frame tube 29 of the vehicle frame 25 .

The continuously variable transmission M is a V-belt type continuously variable transmission housed in the first transmission chamber 140 , and a reduction gear train 145 is provided between the continuously variable transmission M and an axle 143 .

The continuously variable transmission M has a driving side transmission pulley 146, a driven side transmission pulley 149 and an endless V-belt 150 that is wound on the two transmission pulleys 146, 149. The driving side transmission pulley 146 is mounted outside the second ball shaft 46 The side is connected to the end of the crankshaft 44. The driven pulley 149 has an axis parallel to the crankshaft 44, and is mounted on a passive pulley 149 that is freely rotatably supported on the rear of the box main body 137 and on the right side cover 139 through a centrifugal clutch 148. on axis 147.

The driving side transmission pulley 146 is composed of a fixed pulley half 146 a fixed to the crankshaft 44 and a movable pulley half 146 b axially slidably mounted on the crankshaft 44 . A V-shaped annular groove 151 is formed between the pulley halves 146a, 146b, and a V-belt 150 is inserted into the annular groove 151 . On the back side of the movable sheave half body 146a, a slant plate 152 is fixedly attached to the crankshaft 44, and a plurality of heavy rollers 153 are accommodated in a floating state between the movable sheave half body 146a and the slant plate 152. When the rotational speed of the crankshaft 44 increases, the heavy roller 153 subjected to the centrifugal force moves outward in the radial direction of the crankshaft 44 so that the movable belt radius 146a approaches the fixed pulley half 146b. Thereby, the contact radius of the V-belt 150 with both pulley halves 146a, 146b becomes large.

In addition, the driven-side transmission pulley 149 has a support cylinder 154, a fixed pulley half 149a, and a movable pulley half 149b; Above: the fixed pulley half body 149a is integrally formed on the support cylinder 154, the movable pulley half body 149b can be separated from the fixed pulley half body 149a, and is supported on the support cylinder 154, while being moved toward the fixed pulley The half body 149a is biased, and the V-belt 150 is inserted into the V-shaped annular groove 155 formed between the two pulley halves 149a, 149b. The fixed pulley half 149a moves toward the movable pulley 149b so that the contact radius of the V-belt 150 and the driven-side drive pulley 149 becomes smaller as the contact radius between the V-belt 150 and the drive-side drive pulley 146 becomes larger. Axially moved, thereby, a continuously variable speed change between the crankshaft 44 and the driven shaft 147 corresponding to the rotation of the crankshaft 44 is performed.

A recoil shaft 156 is rotatably supported on the left side cover 138 in the transmission case 136 , and a recoil pedal 157 (see FIG. 1 ) is provided at an outer end of the recoil shaft 156 . In addition, on the inner side of the left side cover 138, between the recoil shaft 156 and the crankshaft 44, a recoil starter device 158 is provided, and the recoil starter device 158 can activate the recoil pedal 157 according to the pedaling action. The power of recoil shaft 156 is transmitted to crankshaft 44 .

The reduction gear train 94 is arranged between the driven shaft 147 and the axle 143, and is accommodated in the second transmission chamber 141. The rotational power of the driven shaft 147 in the continuously variable transmission M is decelerated by the reduction gear train 94 and then transmitted to the rear wheels. Axle 143 for WR.

Between the front parts of the two rear frame pipes 29, 30 in the vehicle frame 25, a storage box 160 capable of storing a helmet and the like is supported in a manner arranged above the above-mentioned engine E. The fuel tank 161 is supported.

The front part of the upper frame portion 29b in the left rear frame pipe 29 of the two rear frame pipes 29, 30 supports the air cleaner 162 for secondary air, and the air cleaner 162 for the secondary air is used for cleaning Secondary air supplied to the exhaust port 48 of the engine E. The inlet of the air cleaner 162 for secondary air is connected to the downstream end of the intake pipe 163, and the upstream end of the intake pipe 163 is inserted into the right rear frame pipe 30 of the two rear frame pipes 29, 30. The rear end portion of the upper frame portion 30b.

The secondary air control valve 164 provided between the engine E and the secondary air filter 162 is supported by a support 165 attached to the upper portion of the rising frame portion 29a of the left rear frame pipe 29 .

In the lower part of the rising frame part 29a in the rear frame pipe 29 on the left side, a connecting pipe part 166 communicating with the inside of the rising frame part 29a is provided, which is used to guide the cooling air from the continuously variable transmission M of the power unit P. 167 is connected to the connection pipe part 166 described above.

The vehicle frame 25 is covered with a body cover 168 made of synthetic resin, and the vehicle body cover 168 has a leg cover 169 covering the front of the driver's legs, and a footrest for placing the driver's feet connected to the lower part of the leg cover 169 . The bottom plate 170 and the side cover 171 which is connected with the pedal bottom plate 170 and covers the rear part of the vehicle body from both sides.

The side cover 171 is provided with a seat 172 that covers the storage box 160 and the fuel tank 161 so that the storage box 160 and the fuel tank 161 can be opened and closed from above.

Next, the function of this embodiment will be described. On the crankcase 35 of the engine body 34, an oil pump 66 for sucking oil from an oil storage portion 65 in the crankcase 35 is installed to guide oil used for lubricating the valve train 52. The oil supply passage 67 is connected to the oil pump 66 and is provided on the crankcase 35, the cylinder block 36, the cylinder head 37, and the head cover 38. The temperature detector 73 is mounted on the engine body 34 so that the detection element portion 73a faces the oil supply passage 67. superior.

The oil supply passage 67 that guides the oil discharged from the oil pump 66 to lubricate the valve train 52 is filled with oil regardless of the operating state and posture as long as the engine is running. The detection element portion 73a of the temperature detector 73 is arranged so that it is extremely difficult to be affected by changes in the operating state and posture of the engine E, and at the same time, the engine temperature can always be accurately and quickly detected, and the temperature detected by the temperature detector 73 Oil temperature does not require complex configurations.

In addition, since the oil supply passage 67 is disposed closer to the intake hole 47 than the exhaust hole 48 on the cylinder head 37, it is less likely to be affected by heat radiation from the outer surface of the engine body 34, even when the engine is running. The engine temperature can be detected accurately and quickly even at low rotation speed (idling state) after E startup.

In addition, since the engine E is constituted as a forced air-cooled engine by providing the cooling fans 36a..., 37a... for air cooling on the cylinder block 36 and the cylinder head 37, the temperature detector 73 is installed in a place where no air-cooling fan is provided. Therefore, the engine temperature can be accurately detected without being affected by the cooling fans 36a..., 37a..., and the structure for attaching the temperature detector 73 is also simple.

Since the motorcycle starter 111 for opening and closing the starting mixed gas 113 provided on the gasifier 108 is installed on the gasifier 108 connected to the air intake hole 47, the motorcycle starter 111 is activated according to the temperature detector. The detection value of 73 is energized and controlled, so that the air-fuel mixture supplied to the engine E at startup 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.

In addition, the cylinder block 36 and the cylinder head 37 are covered by the shroud 82 formed between the cylinder block 36 and the cylinder head 37, and the flow path 81 for circulating the air for forced air cooling is covered so as not to be affected by the forced cooling air. By installing a temperature detector 73 on the cover 38 in a manner of influencing the engine, the correct engine temperature can be detected while the engine is being forced air cooled.

On the upper side of the cylinder head 37, there is provided a flat mounting surface 97 that opens the intake hole 47, and the intake pipe 98 is connected to the mounting surface 97 via a heat insulator 99. On the upper cover member 83 of the shroud 82, An opening 105 for fitting and positioning the heat insulator 99 is provided.

Therefore, by being fitted in the opening 105, the heat insulator 99 is positioned and held on the shield 82, and the heat insulator 99 functions as a guide for the bolts 104 ... In the screw holes 103... on the mounting surface 97 of the cylinder head 37, screwing and fastening of the bolts 104... to the screw holes 103... are facilitated, and assemblability can be improved.

In addition, since the exhaust port 106 is formed between a part of the inner surface of the opening 105 provided on the upper cover member 83 made of synthetic resin and a part of the side surface of the heat insulator 99, Hot air heats the intake pipe 98 and can improve the warm-up performance. In addition, the mold part for forming the opening 105 when molding the upper cover member 83 can be relatively enlarged including the part corresponding to the above-mentioned air outlet 106, and the strength can be improved, thereby contributing to the improvement of the metal mold. mold life.

Furthermore, since the thickness T of the heat insulator is set to be larger than the distance between the mounting surface 97 and the shield 82, by fitting the heat insulator 99 into the opening 105 so as to be pressed against the mounting surface 97, it is possible to prevent the When assembling, the heat insulator 99 falls off from the shield 82, so that the assemblability can be further improved.

Although the spark plug cap 121 connected to the spark plug 51 mounted on the right side of the cylinder head 37 and the ignition coil 126 are connected through the high-voltage wire 123, the ignition coil 126 is positioned behind the cylinder head 37 and supports the rear frame on the right side. In the tube 30 , the other end of the high voltage wire 123 connected to the ignition coil 126 is connected to the plug cap 121 by detouring from the front of the plug cap 121 in a substantially U-shape to the rear.

Therefore, the high-voltage electric wire 123 connected to the plug cap 121 extends forward from the plug cap 121 , even if the plug cap 121 is connected to the frame member arranged outside the plug cap 121 in the frame 25 , that is, the rear frame tube 30 on the right side. The narrow intervals between them can also avoid interference with the vehicle frame 25, increase the degree of freedom in arranging the high-voltage wires 123, and increase the life of the high-voltage wires 123 by setting the bending radius of the high-voltage wires 123 relatively large.

The shroud 82 has a pair of upper and lower cover members 83, 84 that are combined up and down to cover the cylinder head 36 and the cylinder head 37 in cooperation with each other, and are used to fit the fitting hole 120 of the spark plug cap 121 connected to the spark plug 51. The spark plug 51 is mounted on the right side surface of the cylinder head 37 formed between the joint surface 86 of the two cover members 83 and 84 . Furthermore, the upper cover member 83 is integrally provided with a shielding edge 122 that covers the fitting portion of the plug cap 121 that fits into the fitting hole 120 from above, and the elastic force acting from the high-voltage electric wire 123 is directed to the direction around the axis of the spark plug 56. One side of the plug cap 121 which tends to rotate is in contact with and engaged with a detent positioning portion 122 a formed on the shroud 122 to support the spark plug cap 121 against the above-mentioned elastic force.

The spark plug cap 121 can prevent the spark plug cap 121 from rotating around the axis of the spark plug 51 when the engine is running because it is in contact with the anti-rotation positioning portion 122a formed on the shielding edge 122 by the elastic force acting from the high-voltage electric wire 123, thereby Vibration of the high-voltage electric wire 123 can be prevented, and contact between the high-voltage electric wire 123 and other parts can be effectively prevented.

Moreover, since the fitting portion where the spark plug cap 122 is fitted to the fitting hole 120 is covered from above by the shielding edge 122, muddy water, etc. falling due to a collision with a frame above the engine body 34 such as the storage box 160 can be prevented from adhering. On the connecting portion of the high voltage electric wire 123 and the spark plug cap 121 .

In addition, the clamp 124 holding the high-voltage electric wire 123 is mounted on the clamp mounting seat 125 connected to the shielding edge 122 and formed on the upper cover member 83, so the high-voltage electric wire 123 can be held near the spark plug 121, Therefore, the vibration of the high-voltage electric wire 123 can be prevented more effectively, and the strength of the shielding edge 122 can be increased by the clamp mounting seat 125 .

In addition, a pair of hooks 128, 128 and a pair of connection walls 129, 130 are integrally provided on the upper cover member 83 of the shield 82, and a right-angled quadrilateral surrounded by these hooks 128, 128 and connection walls 129, 130 is provided. The above-mentioned pair of hooks 128, 128 have joint protrusions 128a, 128a protruding toward the side close to each other at the front end, and stand upright from the outer surface of the upper cover member 83 opposite to each other, and the above-mentioned pair of connecting walls 129 , 130 are connected between the above-mentioned two hooks 128, 128 and stand upright from the outer surface of the upper cover member 83 while facing each other.

A cable 133 and a pipe 134 are clamped between the joint protrusions 128a, 128a of the two hooks 128, 128 and the above-mentioned two connecting walls 129, 130, and the cables 133 and the pipe 134 are pressed into the above-mentioned two hooks 128, 128 in a stacked manner. between.

Therefore, when the upper cover member 83 formed of synthetic resin is molded, the pair of hooks 128, 128 and the pair of connecting walls 129, 130 can be integrally molded with a simple mold structure without using a slide mold, without using a motorized two. The parts other than the upper cover member 83 that the wheeled vehicle has can stably support the cable 133 and the pipe 134 by using the two hooks 128, 128 and the two connecting walls 129, 130, and the number of parts and the number of man-hours for installation can be reduced. At the same time, stable support of the cable 133 and the pipe 134 to the flat surface of the upper cover member 83 can be obtained.

Further, the through hole 131 is covered by the overlapping cables 133 and tubes 134 , and the inside of the upper cover member 83 , that is, the inside of the shield 82 cannot be seen from the through hole 131 in a state where the cables 133 and the tube 134 are supported.

That is, the through-hole 131 is covered by the cables 133 and the tubes 134 stacked on top of each other, so that the leakage of cooling air from the shroud 82 can be prevented, and the cooling performance of the forced air-cooled engine E can be stably maintained, and the cables can be supported on the shroud 82. 133 and the pipe 134, and can prevent the cooling air from leaking through the through hole 131, so dust will not be ejected to the outer surface side of the shroud 82, thereby preventing deterioration of the appearance.

The above-mentioned cable 133 has a soft vinyl sheath and is connected to the temperature detector 73, and the above-mentioned tube 134 is formed of a hard elastic material in order to guide ventilation gas, and is connected to the head cover 38, so that the vinyl on the outside of the cable 133 The resin sheath is fully in close contact with the two connecting walls 129, 130, and at the same time, the coupling protrusions 128a, 128a at the front ends of the two hooks 128, 128 are firmly coupled to the outside of the pipe 134, thereby enabling the cable to be supported more reliably. 133 and pipe 134.

And above-mentioned hook 128 is made up of base plate part 128b and a plurality of, for example, two branch plate parts 128c, 128c, and its base end portion of this base plate part 128b is connected with upper cover member 83 with its whole length, and above-mentioned two branch plate parts 128c, 128c The cable 133 and the pipe 134 are connected to the above-mentioned substrate portion 128b at a plurality of locations at intervals in the longitudinal direction of the cable 133 and the pipe 134, and at the same time, the above-mentioned coupling convex portion 128a is protrudingly provided on the front end portion, and the connecting walls 129, 130 are connected to each other. The reinforcement wall 132 which receives the cable 133 between each branch plate part 128c, 128c is provided so that it may straddle between both hooks 128,128.

Therefore, since the cable 133 on the inner side is also supported by the reinforcing wall 132 , the cable 133 and the pipe 134 can be supported more stably, and the strength of the two hooks 128 , 128 can be increased by the reinforcing wall 132 .

The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the invention described in the claims of the present application.

As described above, according to the first aspect of the present invention, since the heat insulator is fitted into the opening, the heat insulator is positioned and held on the cover, and the screwing and fastening of the bolts to the screw holes are facilitated. , can improve assembly.

According to the second aspect of the present invention, the warm-up performance can be improved by heating the intake duct with the hot air discharged from the exhaust port, and the metal mold part for forming the opening during molding of the guard can be made to contain the same exhaust gas as described above. The part corresponding to the tuyeres is larger in shape, thereby improving its strength, which can help to increase the life of the metal mold.

According to the third technical solution of the present invention, it is characterized in that, on the basis of the composition of the invention of the second technical solution, by fitting the heat insulator into the installation part by pressing it against the installation surface, it is possible to prevent Assemblability can be further improved by detaching the heat shield from the shield during assembly.

Claims (3)

1. The intake connection structure of the forced air-cooled engine is provided with a mounting surface (97) that makes the air intake hole (47) open on the cylinder head (37) covered by the guard cover (82), and on the mounting surface ( 97) is connected to the intake pipe (98) with a heat insulating element (99) sandwiched between it, and it is characterized in that an opening (105) for fitting and positioning the heat insulating element (99) is provided on the shield (82) ). 2. The intake connection structure of a forced air-cooled engine according to claim 1, characterized in that a part of the opening (105) provided on the shroud (82) formed of synthetic resin An air outlet (106) is formed between the inner surface and a part of the side surface of the heat insulating member (99). 3. The intake connection structure of a forced air-cooled engine according to claim 2, characterized in that, the thickness of the heat insulator (99) is set to be lower than the thickness of the mounting surface (97) and the shroud. The interval between (82) is large.

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