JP6795644B2 - Swing unit type power unit - Google Patents

Description

The present invention has a crankshaft, a centrifugal fan fixed to one end of the crankshaft and rotating around the rotation axis of the crankshaft, and an opening that accommodates the centrifugal fan and allows the airflow of the centrifugal fan to flow out in parallel with the rotation axis. The present invention relates to a swing unit type power unit provided with a crankcase.

Patent Document 1 discloses a control device for an internal combustion engine configured as a single cylinder. The control device is a single-cylinder internal combustion engine that detects misfires due to the overlean air-fuel ratio. In the control device, it is determined whether or not the amount of change in the angular velocity of the crankshaft exceeds a predetermined threshold value between the front and rear combustion cycles. When the number of times the amount of change exceeds the threshold value reaches the specified number of times during the preset number of cycles, the control device estimates the misfire of the internal combustion engine.

Patent Document 2 discloses a ring gear (detected body) attached to a crankshaft of an internal combustion engine in determining a misfire. The tip of an eddy current type minute displacement sensor (detection sensor) faces the outer peripheral surface of the ring gear. The micro-displacement sensor detects the crank angle. The positional relationship between the crank chamber of the internal combustion engine and the minute displacement sensor is not disclosed.

Japanese Unexamined Patent Publication No. 2014-199040 JP-A-2002-371906

In an internal combustion engine, the piston reciprocates linearly along the cylinder axis, so that the internal combustion engine vibrates. Especially in a single-cylinder internal combustion engine, the amplitude of vibration is large along the cylinder axis. Therefore, it is desirable that the detection sensors be arranged in a layout that intersects the cylinder axis around the crankshaft at an intersection angle as close to 90 ° as possible. On the other hand, for example, in a swing unit type water-cooled power unit, an opening for discharging the cooling air of the radiator may be located at a position where the crankshaft intersects the cylinder axis at an intersection angle of 90 °.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a swing unit type power unit that realizes a layout of a detection sensor that is not easily affected by the reciprocating motion of a piston when detecting a crank angle.

According to the first aspect of the present invention, a crankshaft, a centrifugal fan fixed to one end of the crankshaft and rotating around the rotation axis of the crankshaft, and the centrifugal fan are housed and parallel to the rotation axis. A crank case having an opening for flowing out the airflow of the centrifugal fan, a detected object fixed to the crankshaft and rotating integrally with the crankshaft, and the opening in the circumferential direction around the rotation axis in a side view. Provided is a swing unit type power unit including a detection sensor that is biased toward the front end or the rear end of the above-mentioned body, faces the trajectory of the detected body, and generates a pulse signal according to the movement of the detected body. ..

According to the second side surface, in addition to the configuration of the first side surface, the detection sensor is arranged on the outer surface of the crankcase so as to spread in the circumferential direction around the rotation axis in the side view in a direction away from the opening. ..

According to the third side surface, in addition to the configuration of the first or second side surface, the swing unit type power unit is coupled to the crankcase and is located in front of the crankcase, and the crankshaft is located in the front-rear direction of the vehicle. It includes a cylinder block that guides the linear reciprocating motion of the piston connected by a connecting rod, and a rear wheel that is arranged behind the crankcase and has an axle parallel to the rotation axis of the crankshaft.

According to the fourth side surface, in addition to the configuration of the third side surface, an oil pan is formed in the crankcase below the crankshaft, and the detection sensor is arranged above the crankshaft.

According to the fifth side surface, in addition to the configuration of the fourth side surface, the swing unit type power unit is located on the rotation axis extending from one end of the crankshaft and is connected to the crankcase, and at least the cylinder. It is further equipped with a radiator that exchanges heat with the outside air from the cooling water flowing through the block.

According to the sixth side surface, in addition to the configuration of the fifth side surface, the swing unit type power unit has a first airflow wall extending in parallel with the rotation axis and partitioning a space connected to the opening, and the first airflow wall. It has a second wind guide wall that continuously guides the airflow flowing out from the opening toward the rear wheel following a curved surface, and is fixed to the outer surface of the crankcase. An airflow guiding member that covers the detection sensor is further provided.

According to the seventh side surface, in addition to the configuration of the sixth side surface, the wind guide member is integrally formed with a shielding plate extending downward from the wind guide member toward the crankcase behind the detection sensor. To.

According to the eighth side surface, in addition to the configuration of the seventh side surface, the wind guide member projects outward from the top plate of the wind guide member facing the outer surface of the crankcase and accommodates the upper end of the detection sensor. A protruding wall is formed.

According to the ninth side surface, in addition to the configuration of the first side surface, the detected body, which is arranged in an annular shape along the track, is provided on the outer periphery thereof and is superposed on the crankshaft from the axial direction of the crankshaft. An annular plate and a cover plate that is continuous from the annular plate toward the rotation axis and forms an oil pool between the annular plate and the crankshaft are provided, and a gasket is sandwiched between the annular plate and the crankshaft. ..

According to the tenth aspect, in addition to the configuration of the ninth aspect, the gasket has a bead that is crushed when the annular plate is fastened to the crankshaft.

According to the eleventh side surface, in addition to the configuration of the ninth or tenth side surface, the crankshaft is connected to the oil sump and is formed with an oil passage for taking in oil from the oil sump based on centrifugal force. ..

According to the twelfth side surface, in addition to the configuration of the eleventh side surface, the crankshaft has a shaft end facing the oil sump, and includes a crankpin connected to a connecting rod, and the crankpin has the said. An oil passage and a supply passage extending from the oil passage to the bearing of the connecting rod are formed.

According to the first aspect, the object to be detected rotates integrally with the crankshaft according to the rotation of the crankshaft. The detection sensor generates a pulse signal according to the movement of the object to be detected. The airflow generated by the rotation of the centrifugal fan flows out from the opening along the outer surface of the crankcase in parallel with the rotation axis of the crankshaft. Since the detection sensor is biased toward the front end or the rear end of the opening in the side view, the interference between the detection sensor and the airflow flowing out from the opening is suppressed. Therefore, even if the opening is located at a position where it intersects the cylinder axis at a 90 ° intersection around the crankshaft, the detection sensor can move as much as possible around the crankshaft with respect to the cylinder axis without obstructing the flow of airflow. It can be arranged in a layout that intersects at an intersection angle close to 90 °. The influence of vibration can be suppressed as much as possible when detecting the crank angle.

According to the second aspect, since the detection sensor is arranged without interfering with the airflow flowing out from the opening, good airflow circulation can be realized.

According to the third aspect, the cylinder block guides the linear reciprocating motion of the piston along the cylinder axis extending in the front-rear direction of the vehicle. Since the rear wheels are located behind the crankcase, even if the detection sensor is placed in a layout that intersects the crankshaft at an intersection angle as close to 90 ° as possible with respect to the cylinder axis, the detection sensor and the rear wheels Interference can be avoided. The crankcase and rear wheels can be as close as possible. The power unit can be configured compactly.

According to the fourth aspect, when the detection sensor is placed in a layout that intersects the crankshaft at an intersection angle as close to 90 ° as possible with respect to the cylinder axis, the detection sensor may be placed above the crankshaft. As a result, the detection sensor can be kept away from the oil pan. The influence of oil in the crankcase on the detection sensor can be suppressed.

According to the fifth aspect, when the centrifugal fan rotates, an airflow of outside air toward the centrifugal fan is generated along the rotation axis of the crankshaft. The airflow of the outside air passes through the radiator and draws heat from the cooling water of the radiator. The airflow after heat exchange is discharged to the outside of the crankcase through the opening.

According to the sixth side surface, the airflow flowing out from the opening parallel to the rotation axis of the crankshaft is guided by the first wind guide wall and the second wind guide wall toward the rear wheels. Since the wind guide member covers the detection sensor, the detection sensor can be protected from stones and water splashing from the road surface on the outside of the crankcase. Moreover, since the exposure of the detection sensor is avoided on the outside of the crankcase, the design of the power unit can be well maintained.

According to the seventh aspect, the detection sensor can be protected from stones and water that are rolled up on the rear wheels. In particular, since the shielding plate extends downward from the wind guide member above the detection sensor in the direction of rotation of the rear wheels, the detection sensor can be protected from stones and water.

According to the eighth side surface, the top plate of the airflow guide member can be located close to the outer surface of the crankcase regardless of the protruding height of the detection sensor protruding from the outer surface of the crankcase, so that the air resistance of the traveling vehicle can be reduced. The increase can be avoided and the flow of the airflow flowing out from the opening of the crankcase inside the air guide member can be well maintained.

According to the ninth aspect surface, even if centrifugal force acts during the rotation of the crankshaft, oil leakage from the oil pool in the centrifugal direction can be prevented.

According to the tenth aspect, the degree of adhesion between the crankshaft and the object to be detected can be increased by the action of the bead.

According to the eleventh aspect, oil can efficiently flow into the oil passage from the oil pool.

According to the twelfth aspect, oil can be efficiently supplied from the oil sump to the bearing of the connecting rod.

It is a side view which shows typically the scooter type motorcycle which concerns on one Embodiment of a saddle riding type vehicle. It is a horizontal sectional view of the power unit along line 2-2 of FIG. It is an enlarged side view of the engine body which shows schematic structure of the water cooling system including a water pump and a radiator. It is an enlarged sectional view of the internal combustion engine observed in the cut surface including the rotation axis of a crankshaft. It is an enlarged sectional view of the internal combustion engine observed in the cut plane orthogonal to the rotation axis of a crankshaft. It is an enlarged sectional view of the generator observed in the cut surface including the rotation axis of a crankshaft. It is a bottom view of the air guide member. It is an enlarged perspective view of a wind guide member. FIG. 5 is an enlarged cross-sectional view schematically showing a centrifugal fan observed on a cut surface orthogonal to the rotation axis of a crankshaft. FIG. 4 is an enlarged cross-sectional view of an internal combustion engine showing a gasket sandwiched between a crankshaft and an annular plate, corresponding to FIG. It is an enlarged disassembled perspective view of a crank web, a gasket and an annular plate. It is a conceptual diagram of the gasket which has a bead which concerns on one specific example. It is a conceptual diagram of the gasket which has a bead which concerns on another specific example.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, the front-rear, up-down, and left-right directions refer to the directions seen by the occupants on the motorcycle.

FIG. 1 schematically shows a scooter-type motorcycle according to an embodiment of a saddle-riding vehicle. The motorcycle 11 includes a vehicle body frame 12 and a vehicle body cover 13 mounted on the vehicle body frame 12. The vehicle body frame 12 is connected to the head pipe 14, a pair of left and right main frames 15 that descend from the head pipe 14 behind the front wheel WF, are curved at the lower end, and extend rearward in parallel with the ground, and the rear portion of the main frame 15. The cross pipe 16 extends in the vehicle width direction, and the rear frame 17 continuously rises in front of the rear wheel WR from the main frame 15, curves at the upper end, and gently extends rearward in the vehicle front-rear direction. A front fork 18 that rotatably supports the front wheel WF and a rod-shaped steering handle 19 are rotatably supported on the head pipe 14.

The occupant seat 21 is mounted on the vehicle body cover 13 above the rear frame 17. The vehicle body cover 13 includes a front cover 22 that covers the head pipe 14 from the front, a leg shield 23 that is continuous from the front cover 22, and a main frame 15 that is continuous from the lower end of the leg shield 23 and is between the occupant seat 21 and the front wheel WF. It is provided with a step floor 24 arranged above the above.

A swing unit type power unit 25 is arranged in the space below the rear frame 17. The power unit 25 includes a water-cooled single-cylinder internal combustion engine 26, and a transmission device 27 that is connected to the internal combustion engine 26 and the rear wheel WR and transmits the output of the internal combustion engine 26 to the rear wheel WR. The axle of the rear wheel WR is rotatably supported by both sides at the rear end of the power unit 25 around a horizontal axis.

The internal combustion engine 26 has a crankcase 28 that rotatably supports a crankshaft (described later) around a rotation axis Rx extending parallel to the axle of the rear wheel WR, and is coupled to the crankcase 28 in front of the crankcase 28. It includes a positioned cylinder block 29, a cylinder head 31 coupled to the cylinder block 29, and a head cover 32 coupled to the cylinder head 31. The rear wheel WR is arranged behind the crankcase 28.

The crankcase 28 is rotatably connected to a bracket 33 coupled to the curved region of the rear frame 17 via a link 34 around an axis parallel to the rotation axis Rx. The transmission case 27a of the transmission device 27 is coupled to the crankcase 28. A rear cushion unit 35 is arranged between the rear frame 17 and the power unit 25 at a position away from the link 34 and the bracket 33. Such a power unit 25 functions as a suspension device for the rear wheel WR.

An intake device 37 and an exhaust device 38 are connected to the cylinder head 31. The intake device 37 includes an air cleaner 39 that is supported by the transmission case 27a and sucks and purifies the outside air, and a throttle body 41 as an intake system component that connects the air cleaner 39 to the cylinder head 31. A fuel injection device 42 is attached to the upper side wall of the cylinder head 31. The exhaust device 38 includes an exhaust pipe 43 extending rearward from the lower side wall of the cylinder head 31 through below the internal combustion engine 26, and an exhaust muffler connected to the downstream end of the exhaust pipe 43 and connected to the crankcase 28 (not shown). Cylinder) and.

As shown in FIG. 2, the crankcase 28 is divided into a first case half body 28a and a second case half body 28b. The first case half body 28a and the second case half body 28b cooperate to partition the crank chamber 44. The crank of the crankshaft 45 is housed in the crank chamber 44. A bearing 46a that rotatably supports the crankshaft 45 is assembled to the first case half body 28a. A bearing 46b that rotatably supports the crankshaft 45 is assembled to the second case half body 28b.

A cylinder bore 47 is partitioned in the cylinder block 29. The piston 49 is fitted into the cylinder bore 47 so as to be slidable along the cylinder axis C. The piston 49 is connected to the crank of the crankshaft 45 by a connecting rod 48. The cylinder axis C inclines slightly forward from the horizontal. The cylinder block 29 guides the linear reciprocating motion of the piston 49 along the cylinder axis C. The linear reciprocating motion of the piston 49 is converted into the rotational motion of the crankshaft 45. The combustion chamber 51 is partitioned between the piston 49 and the cylinder head 31. The air-fuel mixture is introduced into the combustion chamber 51 via the intake device 37. The exhaust gas in the combustion chamber 51 is discharged through the exhaust device 38.

Water jackets 52a and 52b that guide the flow of cooling water around the combustion chamber 51 are formed in the cylinder block 29 and the cylinder head 31. The water jacket 52a of the cylinder block 29 is partitioned around the cylinder bore 47 along the mating surface with the cylinder head 31. The water jacket 52b of the cylinder head 31 extends continuously along the ceiling wall of the combustion chamber 51 to the water jacket 52a of the cylinder block 29.

The transmission device 27 is housed in the transmission case 27a and is wound around a drive pulley 53 attached to a crankshaft 45 protruding from the outer surface of the second case half body 28b and a driven pulley 55 attached to the driven shaft 54. A belt-type stepless transmission (hereinafter referred to as "transmission") 57 having a V-belt 56 and steplessly shifting the rotational power transmitted from the crankshaft 45, and a transmission housed in a transmission case 27a. It is provided with a reduction gear mechanism 59 that decelerates the rotational power of 57 and transmits it to the axle 58 of the rear wheel WR.

The transmission case 27a is fastened to the case main body 61 continuous from the second case half body 28b of the crankcase 28 and the case main body 61 to partition the transmission chamber 62 for accommodating the transmission 57 between the case main body 61. The case cover 63 is fastened to the case main body 61 to partition the gear chamber 64 between the case main body 61 and the case main body 61. A reduction gear mechanism 59 is housed in the gear chamber 64.

The drive pulley 53 includes a pulley half body 66 that is coaxially fixed to the crankshaft 45 and has a conical inward facing surface that faces the second case half body 28b, and the pulley half body 66 and the second case half body 28b. It comprises a pulley half body 67 that is coaxially supported by the crankshaft 45 so as to be movable in the axial direction of the crankshaft 45 and has a conical inward surface facing the inward surface of the pulley half body 66. The V-belt 56 is wound between the inward surface of the pulley half body 66 and the inward surface of the pulley half body 67. A weight holding plate 68, which is fixed to the crankshaft 45 so as not to be displaced in the axial direction, faces the outward surface of the pulley half body 67. A centrifugal weight 69 is sandwiched between the cam surface 67a of the pulley half body 67 and the weight holding plate 68. The cam surface 67a moves away from the pulley half body 66 as it moves away from the rotation axis Rx of the crankshaft 45 in the centrifugal direction. Centrifugal force is generated in the centrifugal weight 69 as the crankshaft 45 rotates. The centrifugal weight 69 is displaced in the centrifugal direction by centrifugal force. As the centrifugal weight 69 is displaced in the centrifugal direction while rolling and contacting the cam surface 67a, the pulley half body 67 is driven toward the pulley half body 66. In this way, the pulley half body 67 moves in the axial direction toward the pulley half body 66 according to the rotation of the crankshaft 45, and the winding radius of the V-belt 56 changes.

The driven pulley 55 has a cylindrical shape coaxial with the driven shaft 54, is fixed to the inner cylinder 71 coaxially with the inner cylinder 71 mounted on the coaxial driven shaft 54, and faces the case cover 63. A pulley half body 72 having a conical inward facing surface to be matched, an outer cylinder 73 having a cylindrical shape coaxial with the driven shaft 54 and coaxially mounted on the inner cylinder 71, a pulley half body 72 and a case cover 63. The pulley half body 74 is fixed to the outer cylinder 73 coaxially with the outer cylinder 73 and has a conical inward facing surface facing the inward surface of the pulley half body 72. The V-belt 56 is wound between the inward surface of the pulley half body 72 and the inward surface of the pulley half body 74. The inner cylinder 71 is supported by the driven shaft 54 so as to be relatively rotatable. The outer cylinder 73 is supported by the inner cylinder 71 so as to be relatively rotatable and axially relatively displaceable. The pulley half body 74 moves closer to or away from the pulley half body 72 according to the axial relative displacement of the outer cylinder 73 and the inner cylinder 71.

A centrifugal clutch 75 is attached to the driven shaft 54. The centrifugal clutch 75 includes a clutch plate 75a fixed to the inner cylinder 71. A string winding spring 76 is arranged between the clutch plate 75a and the pulley half body 74. The string-wound spring 76 exerts an elastic force that presses the pulley half body 74 toward the pulley half body 72. When the winding radius of the V-belt 56 increases in the drive pulley 53, the pulley half body 74 moves away from the pulley half body 72 in the driven pulley 55 against the elastic force of the string winding spring 76, and the winding radius of the V-belt 56 decreases. ..

The centrifugal clutch 75 includes an outer plate 75b fixed to the driven shaft 54. The outer plate 75b faces the clutch plate 75a. When the clutch plate 75a rotates, the outer plate 75b is coupled to the clutch plate 75a by the action of centrifugal force. In this way, the rotation of the driven pulley 55 is transmitted to the driven shaft 54. When the engine speed exceeds the set speed, the centrifugal clutch 75 establishes a power transmission state.

The reduction gear mechanism 59 is arranged between the drive gear 77 fixed to the driven shaft 54 protruding into the gear chamber 64, the final gear 78 fixed to the axle 58 of the rear wheel WR, and the drive gear 77 and the final gear 78. The idle gears 79a and 79b are provided. The idle gears 79a and 79b are fixed to a common intermediate shaft 81. The drive gear 77 meshes with the idle gear 85a, and the final gear 78 meshes with the idle gear 85b. In this way, the rotation of the driven shaft 54 is decelerated and transmitted to the axle 58 of the rear wheel WR.

An alternator (ACG) 82 is connected to one end of the crankshaft 45. The alternator 82 includes a tubular rotor 82a fixed to one end of a crankshaft 45 protruding from the outer surface of the first case half body 28a, and a stator 82b surrounded by the rotor 82a and arranged around the crankshaft 45. To be equipped. The stator 82b includes a plurality of stator cores fixed to the first case half body 28a and arranged in an annular shape. The coils are wound around the individual stator cores. The rotor 82a includes a magnet that follows an annular trajectory on the radial outer side of the stator core. The alternator 82 generates electricity according to the relative rotation of the rotor 82a and the stator 82b. The alternator 82 may be used as an ACG starter.

A generator cover 84 that forms a generator chamber 83 with the first case half body 28a is coupled to the first case half body 28a. The alternator 82 is housed in the generator room 83. The generator cover 84 is partitioned with an air introduction port 84a at a position facing one end of the crankshaft 45. A radiator 85 is incorporated in the air inlet 84a. In this way, the radiator 85 is located on the rotation axis Rx extending from one end of the crankshaft 45 and is connected to the crankcase 28.

In the generator room 83, a centrifugal fan 86 that rotates around the rotation axis Rx of the crankshaft 45 is coupled to one end of the crankshaft 45. The centrifugal fan 86 is housed in the space inside the first case half body 28a surrounding the generator chamber 83. The centrifugal fan 86 includes a rotating body 86a fixed to the rotor 82a of the alternator 82, and a plurality of blades rising from the surface of the rotating body 86a in the axial direction of the rotating axis Rx and arranged in the circumferential direction around the rotating axis Rx. It is equipped with 86b. When the centrifugal fan 86 rotates, air is attracted in the axial direction of the rotation axis Rx toward the surface of the rotating body 86a, and air is discharged in the centrifugal direction. The air flowing axially toward the centrifugal fan 86 passes through the radiator 85.

The internal combustion engine 26 is equipped with a water pump 88 that is connected to a camshaft 87 that drives an intake valve and an exhaust valve and discharges cooling water in conjunction with the rotation of the camshaft 87. When the camshaft 87 is rotationally driven, the cam chain 91 is wound around the sprocket 89a of the camshaft 87 and the sprocket 89b of the crankshaft 45.

The water pump 88 circulates the cooling water in a closed path through the radiator 85. As shown in FIG. 3, the path connects the first pipe 92a for connecting the water jacket 52a of the cylinder block 29 to the discharge port 88a of the water pump 88 and the introduction port of the radiator 85 to the water jacket 52b of the cylinder head 31. It is formed by a second pipe 92b and a third pipe 92c that connects the thermostat 93 to the discharge port of the radiator 85. The thermostat 93 is connected to the suction pipe 88b of the water pump 88.

The cooling water discharged from the water pump 88 is introduced from the first pipe 92a into the water jacket 52a of the cylinder block 29. The cooling water circulates through the water jacket 52a of the cylinder block 29 and the water jacket 52b of the cylinder head 31 to cool the internal combustion engine 26. The cooling water discharged from the cylinder head 31 flows into the radiator 85 via the second pipe 92b. The radiator 85 exchanges heat from the cooling water to the outside air. The radiator 85 dissipates heat. The cooling water cooled by the radiator 85 flows into the thermostat 93 from the third pipe 92c and returns to the water pump 88. In this way, the internal combustion engine 26 is cooled.

The radiator 85 includes an upper tank 95a having an upwardly extending filler neck 94, a lower tank 95b arranged below the upper tank 95a, a radiator core 95c arranged between the upper tank 95a and the lower tank 95b, and a vehicle. A tank cover 96 that covers the upper tank 95a from the outside in the width direction is provided. The second pipe 92b is connected to the upper tank 95a. The third pipe 92c is connected to the lower tank 95b. The radiator core 95c may be formed of a pipe that connects the upper tank 95a and the lower tank 95b and allows cooling water to pass from the upper tank 95a to the lower tank 95b, and a heat radiation fin that is coupled to the pipe. The cooling water introduced into the upper tank 95a is cooled by the radiator core 95c and flows into the lower tank 95b.

As shown in FIG. 4, the crank of the crankshaft 45 has a disc-shaped crank web 97 continuous from the crank journal 97a connected to the first case half body 28a by the bearing 46a, and the second case half by the bearing 46b. A disc-shaped crank web 98 continuous from the crank journal 98a connected to the body 28b and held by the crank webs 97 and 98 at positions deviated from the axis of the crank journals 97a and 98a and parallel to the rotation axis Rx. It includes a crank pin 99 that is connected to the large end of the connecting rod 48 so that it can rotate relative to the axis. The individual crank webs 97, 98 have a balance weight 101 projecting from the inward surface at a position deviated from the crank pin 99 around the axis of the crank journals 97a, 98a.

An annular plate 102 formed in an annular shape around the crank journal 97a coaxially with the rotation axis Rx is superposed on the outward surface of the crank web 97. The annular plate 102 is coupled to the crank web 97. On the outer circumference of the annular plate 102, a plurality of retractors (detected bodies) 103 protruding radially outward from the outer circumference of the crank web 97 are continuous. As shown in FIG. 5, the retractors 103 are arranged in an annular shape at equal intervals around the rotation axis Rx of the crankshaft 45. The retractors 103 are arranged, for example, every 10 degrees at a central angle. The retractor 103 is composed of, for example, a magnetic material. As shown in FIG. 4, the cylinder liner fitted to the cylinder block 29 to partition the cylinder bore 47 is formed with a chip 104 forming a relief for the retractor 103. The retractor 103 rotates integrally with the crankshaft 45.

On the inner circumference of the annular plate 102, a covering plate 105 formed in an annular shape around the crank journal 97a coaxially with the rotation axis Rx is continuous. The cover plate 105 forms an oil sump 106 with the outward surface of the crank web 97. The oil sump 106 is connected to an oil passage 107 partitioned in the crank pin 99 along the axis of the crank pin 99. The inner circumference of the cover plate 105 forms an annular gap, that is, a lubricating oil inlet, around the crank journal 97a. The inner circumference of the covering plate 105 may be in contact with the inner ring of the bearing 46a. The cover plate 105 constitutes a centrifugal oil filter in cooperation with the annular plate 102. The centrifugal oil filter filters foreign matter in the lubricating oil based on the centrifugal force during rotation of the crank web 97.

The crank pin 99 is partitioned from a supply path 108 extending in the radial direction (direction orthogonal to the axis) from the oil passage 107. The outer end of the supply path 108 opens into the bearing of the connecting rod 48. The lubricating oil in the oil sump 106 is supplied to the bearing of the connecting rod 48 via the oil passage 107 and the supply passage 108.

As shown in FIG. 5, an oil pan 109 is formed in the crankcase 28 below the crankshaft 45. Lubricating oil in the crankcase 28 flows into the oil pan 109 due to the action of gravity. The suction port 111a of the oil pump 111 opens in the space inside the oil pan 109. The oil pump 111 sucks the lubricating oil in the oil pan 109 from the suction port 111a in conjunction with the rotation of the crankshaft 45 and discharges it toward the oil passage 112 (see FIG. 4) in the crankcase 28. Lubricating oil is supplied from the oil passage 112 to the oil sump 106 and each lubricating portion.

The crankcase 28 is supported by a pulsar sensor (detection sensor) 113 that faces the trajectory of the retractor 103 at the detection end 113a and generates a pulse signal in response to the movement of the retractor 103. The pulsar sensor 113 is inserted from the outside into a sensor hole 114 drilled in the first case half body 28a above the crankshaft 45, and has a sensor body 115a having a detection end 113a facing the crankcase 44 and a rotation axis Rx. A mounting piece 115b that is stacked on the outer surface of the crankcase 28 behind the sensor hole 114 in the circumferential direction and is fastened to the crankcase 28, and extends upward from the upper end of the sensor body 115a on the outside of the crankcase 28 and is folded back. A sensor harness 115c bundled on the side surface of the main body 115a is provided.

The pulsar sensor 113 outputs an electric signal, that is, a pulse signal, depending on the presence or absence of a magnetic material detected in the orbit of the retractor 103, for example, by the action of a magnetoresistive sensor. The angular position of the crankshaft 45 is specified by the pulse signal. In the pulsar sensor 113, the most sensitive detection axis 113b points to the rotation axis Rx. The pulsar sensor 113 is arranged in a layout that intersects the cylinder axis C around the crankshaft 45 at an intersection angle close to 90 °, and is tilted backward at an inclination angle α with respect to the vehicle vertical direction orthogonal to the ground GD. Is held at. The sensor harness 115c extends forward along the outer surface of the crankcase 28.

As shown in FIG. 6, the crankcase 28 is partitioned with an opening 116 that allows the airflow of the centrifugal fan 86 to flow out in parallel with the rotation axis Rx of the crankshaft 45. In the section of the opening 116, a bulging wall 117 is formed in the crankcase 28 at a position outside the outer circumference of the alternator 82 and bulges in the centrifugal direction from the outer wall surface following the outer circumference of the crank web 97. The bulging wall 117 has an inner wall surface parallel to the rotation axis Rx of the crankshaft 45.

On the outer surface of the crankcase 28, a wind guide member 119 for partitioning the air guide path 118 connected to the generator chamber 83 through the opening 116 is fixed to the outer surface of the crankcase 28. The wind guide member 119 covers the pulsar sensor 113 as shown in FIG. The air guide member 119 is formed with a projecting wall 121 that projects upward from the top plate 119a of the air guide member 119 facing the outer surface of the crankcase 28 and accommodates the upper end of the pulsar sensor 113.

With reference to FIGS. 7 and 8, the airflow guide member 119 extends in parallel with the rotation axis Rx of the crankshaft 45, and has a first airflow wall 122 and a first airflow wall 122 that partition a space connected in series with the opening 116. It has a second wind guide wall 123 that continuously guides the airflow flowing out from the opening 116 toward the rear wheel WR following the curved surface. A shielding plate 124 extending downward from the top plate 119a of the wind guide member 119 toward the crankcase 28 is integrally formed on the wind guide member 119 behind the pulsar sensor 113. The shielding plate 124 spreads between the pulsar sensor 113 and the rear wheel WR to shield the pulsar sensor 113 from behind. The shielding plate 124 is reinforced by a rib 125 that stands upright from the top plate 119a of the wind guide member 119.

As shown in FIG. 9, the generator cover 84 includes an enclosure wall 126 that surrounds the outer periphery of the centrifugal fan 86 on the outside of the centrifugal fan 86 continuously and continuously around the rotation axis Rx of the crankshaft 45. The enclosure wall 126 faces the outer periphery of the centrifugal fan 86 and is partitioned by the first partition piece 127a along the rotation direction DR of the centrifugal fan 86. The second partition piece 127b is located at the downstream end of the opening 116 from the upstream end. The first guide wall 126a extending to the outer circumference of the centrifugal fan 86 and the second guide wall extending from the second partition piece 127b to the discharge port 128 located downward in the direction of gravity in the rotation direction DR of the centrifugal fan 86. It has 126b and. The enclosure wall 126 of the generator cover 84 is closest to the outer periphery of the centrifugal fan 86 at the first partition piece 127a and the second partition piece 127b. The first guide wall 126a moves away from the outer circumference of the centrifugal fan 86 as it goes downstream from the first partition piece 127a. The second guide wall 126b moves away from the outer circumference of the centrifugal fan 86 as it goes downstream from the second partition piece 127b. When the centrifugal fan 86 rotates in the rotational direction DR, the air discharged from the centrifugal fan 86 in the centrifugal direction is guided by the first guide wall 126a and flows toward the opening 116, and is also guided by the second guide wall 126b. It flows toward the discharge port 128.

The pulsar sensor 113 is arranged at the rear end of the opening 116 in the circumferential direction around the rotation axis Rx in a side view observed from infinity of the rotation axis Rx. The mounting piece 115b of the pulsar sensor 113 is arranged in a direction (here, rearward) away from the opening 116 in the circumferential direction around the rotation axis Rx in a side view. However, the pulsar sensor 113 may be arranged biased toward the front end of the opening 116 in the circumferential direction around the rotation axis Rx in the side view. In that case, the mounting piece 115b may be arranged in front of the sensor main body 115a in the circumferential direction around the rotation axis Rx in the side view.

Next, the operation of the power unit 25 according to the present embodiment will be described. When the internal combustion engine 26 repeats the strokes of intake, compression, combustion, and exhaust, the piston 49 reciprocates linearly in the cylinder bore 47. The linear reciprocating motion of the piston 49 is converted into the rotational motion of the crankshaft 45 by the action of the crankshaft 45 and the connecting rod 48. The retractor 103 rotates integrally with the crankshaft 45 around the rotation axis Rx. The retractor 103 moves along an annular orbit. The pulsar sensor 113 outputs a pulse signal depending on the presence or absence of a magnetic material detected in the orbit of the retractor 103. The angular position of the crankshaft 45 is specified by the pulse signal.

The rotation of the crankshaft 45 is transmitted to the camshaft 87 by the action of the cam chain 91. The water pump 88 discharges cooling water in conjunction with the rotation of the camshaft 87. The cooling water circulates in the path, takes heat energy from the cylinder block 29 and the cylinder head 31, and dissipates heat from the radiator 85. In this way, the internal combustion engine 26 is cooled.

The rotation of the crankshaft 45 causes the centrifugal fan 86 to rotate. When the centrifugal fan 86 rotates, an air flow of outside air toward the centrifugal fan 86 is generated along the rotation axis Rx of the crankshaft 45. The outside air flows in the axial direction of the rotation axis Rx from the air introduction port 84a of the generator cover 84. The outside air passes through the radiator 85 and exchanges heat with the cooling water. Cooling of the cooling water is promoted in the radiator 85.

A part of the air discharged from the centrifugal fan 86 in the centrifugal direction is guided by the first guide wall 126a and flows toward the opening 116. The airflow flows out from the opening 116 along the rotation axis Rx of the crankshaft 45. The airflow flows into the air guide path 118 in the air guide member 119. In the airflow path 118, the direction of the airflow is changed by the action of the first airflow wall 122 and the second airflow wall 123, and the airflow travels in a direction orthogonal to the rotation axis Rx. In this way, the airflow is discharged to the outside of the crankcase 28 toward the rear wheel WR.

A part of the air discharged from the centrifugal fan 86 in the centrifugal direction is guided by the second guide wall 126b and flows toward the discharge port 128. The airflow is discharged from the discharge port 128 toward the ground GD to the outside of the crankcase 28.

In the present embodiment, the pulsar sensor 113 is arranged rearward from the path of the airflow flowing out from the opening 116 along the outer surface of the crankcase 28 in parallel with the rotation axis Rx of the crankshaft 45. Since the interference between the pulsar sensor 113 and the airflow flowing out from the opening 116 is minimized, the opening 116 is located at a position where it intersects the cylinder axis C around the crankshaft 45 at a 90 ° intersection angle. However, the pulsar sensor 113 is arranged in a layout that intersects the cylinder axis C around the crankshaft 45 at an intersection angle as close to 90 ° as possible. Therefore, even if the internal combustion engine 26 vibrates in the direction of the cylinder axis C in response to the linear reciprocating motion of the piston 49, the influence of the vibration is suppressed as much as possible when detecting the crank angle. In particular, in the single-cylinder internal combustion engine 26, since the amplitude of vibration is large along the cylinder axis C, the influence of vibration is effectively suppressed.

In the pulsar sensor 113 according to the present embodiment, the mounting piece 115b is located behind the sensor hole 114 in the vehicle front-rear direction. Therefore, the mounting piece 115b is arranged so as to be further rearward than the sensor main body 115a from the path of the airflow flowing out from the opening 116 along the outer surface of the crankcase 28 in parallel with the rotation axis Rx of the crankshaft 45. Since the mounting piece 115b of the pulsar sensor 113 is arranged without interfering with the airflow flowing out from the opening 116, good airflow flow is realized.

In the power unit 25 according to the present embodiment, the cylinder block 29 is coupled to the crankcase 28 and is located in front of the crankcase 28 to guide the linear reciprocating motion of the piston 49 in the vehicle front-rear direction. Since the rear wheel WR is arranged behind the crankcase 28, even if the pulsar sensor 113 is arranged in a layout that intersects the cylinder axis C around the crankshaft 45 at an intersection angle as close to 90 ° as possible, the pulsar sensor Interference between the 113 and the rear wheel WR is avoided. The crankcase 28 and the rear wheel WR can be as close as possible. The power unit 25 is compactly configured.

In the present embodiment, the oil pan 109 is formed in the crankcase 28 below the crankshaft 45, while the pulsar sensor 113 is arranged above the crankshaft 45. When the pulsar sensor 113 is placed in a layout that intersects the cylinder axis C around the crankshaft 45 at an intersection angle as close to 90 ° as possible, the pulsar sensor 113 is placed above the crankshaft 45, resulting in a pulsar. The sensor 113 is moved away from the oil pan 109. The influence of oil in the crankcase 28 on the pulsar sensor 113 is suppressed.

The airflow guide member 119 according to the present embodiment extends parallel to the rotation axis Rx of the crankshaft 45 and is continuous with the first airflow wall 122 and the first airflow wall 122 that partition the space connected to the opening 116. Therefore, it has a second wind guide wall 123 that guides the airflow flowing out from the opening 116 toward the rear wheel WR following the curved surface. The airflow flowing out from the opening 116 in parallel with the rotation axis Rx of the crankshaft 45 is guided by the first wind guide wall 122 and the second wind guide wall 123 toward the rear wheel WR. Since the wind guide member 119 covers the pulsar sensor 113, the pulsar sensor 113 is protected from stones and water splashing from the road surface on the outside of the crankcase 28. Moreover, since the exposure of the pulsar sensor 113 is avoided on the outside of the crankcase 28, the design of the power unit 25 is well maintained.

A shielding plate 124 extending downward from the wind guide member 119 toward the crankcase 28 is integrally formed on the wind guide member 119 behind the pulsar sensor 113. The pulsar sensor 113 is protected from stones and water that are rolled up on the rear wheel WR. In particular, since the shielding plate 124 extends downward from the wind guide member 119 above the pulsar sensor 113 following the rotation direction of the rear wheel WR, the pulsar sensor 113 is protected from stones and water.

The air guide member 119 according to the present embodiment is formed with a projecting wall 121 that projects outward from the top plate 119a of the air guide member 119 facing the outer surface of the crankcase 28 and accommodates the upper end of the pulsar sensor 113. Regardless of the protruding height of the pulsar sensor 113 protruding from the outer surface of the crankcase 28, the top plate 119a of the airflow guiding member 119 can be located close to the outer surface of the crankcase 28, so that the increase in air resistance of the traveling vehicle is increased. While being avoided, the flow of the airflow flowing out from the opening 116 of the crankcase 28 inside the air guide member 119 is well maintained.

In addition, as shown in FIG. 10, a gasket 131 may be sandwiched between the annular plate 102 and the outward surface of the crank web 97. As shown in FIG. 11, the gasket 131 is formed in a continuous annular shape along the outer circumference of the crank web 97. The gasket 131 has fastening portions 131a which are arranged at equal intervals in the circumferential direction and form circular holes 133 for receiving fasteners. On the outward surface of the crank web 97, a receiving surface 134 that spreads in a plane orthogonal to the rotation axis Rx and continues along the outer circumference without interruption to receive the gasket 131 is formed. The gasket 131 is in close contact with the receiving surface 134. The gasket 131 is fastened together with the annular plate 102 to the crank web 97 with a fastener. The fastener is inserted into the circular hole 135 of the annular plate 102, penetrates the circular hole 133 of the fastening portion 131a, and is screwed into the screw hole 136 of the crank web 97.

Even if centrifugal force acts during the rotation of the crankshaft 45, leakage of lubricating oil from the oil sump 106 in the centrifugal direction is prevented. Since the crankshaft 45 is connected to the oil sump 106 to form an oil passage 107 that takes in lubricating oil from the oil sump 106 based on centrifugal force, the lubricating oil can be efficiently supplied from the oil sump 106 to the oil passage 107. Inflow. Since the crank pin 99 is formed with a supply path 108 extending from the oil passage 107 to the bearing of the connecting rod 48, lubricating oil is efficiently supplied from the oil sump 106 to the bearing of the connecting rod 48.

As shown in FIG. 12, the gasket 131 may have a bead 137 that is crushed when the annular plate 102 is fastened to the crank web 97. By the action of the bead 137, the degree of adhesion between the crank web 97 and the annular plate 102 is enhanced. The bead 137 is continuous over the entire circumference including the fastening portion 131a. At the fastening portion 131a, the bead 137 is arranged radially inside the circular hole 133. As shown in FIG. 13, the bead 138 may be continuous except for the fastening portion 131a.

25 ... swing unit type power unit, 28 ... crankcase, 29 ... cylinder block, 45 ... crankshaft, 48 ... connecting rod, 49 ... piston, 58 ... (rear wheel) axle, 85 ... radiator, 86 ... centrifugal fan, 99 ... Crankpin, 102 ... Ring plate, 103 ... Detected object (retractor), 105 ... Cover plate, 106 ... Oil pool, 107 ... Oil passage, 108 ... Supply passage, 109 ... Oil pan, 113 ... Detection sensor (pulsar) Sensor), 115b ... Mounting piece, 116 ... Opening, 119 ... Air guide member, 119a ... Top plate, 121 ... Protruding wall, 122 ... First wind guide wall, 123 ... Second wind guide wall, 124 ... Shielding plate, 131 ... Gasket, 137 ... Bead, 138 ... Bead, Rx ... Rotating rod (of crankshaft), WR ... Rear wheel.

Claims (12)

Crankshaft (45) and
A centrifugal fan (86) fixed to one end of the crankshaft (45) and rotating around the rotation axis (Rx) of the crankshaft (45).
A crankcase (28) that accommodates the centrifugal fan (86) and has an opening (116) that allows the airflow of the centrifugal fan (86) to flow out in parallel with the rotation axis (Rx).
A body to be detected (103) that is fixed to the crankshaft (45) and rotates integrally with the crankshaft (45).
When viewed from the side, the detected body (116) is arranged so as to be biased toward the front end or the rear end of the opening (116) in the circumferential direction around the rotation axis (Rx), and faces the trajectory of the detected body (103). A detection sensor (113) that generates a pulse signal according to the movement of 103) and
A swing unit type power unit characterized by being equipped with. In the swing unit type power unit according to claim 1, the detection sensor (113) expands in the circumferential direction around the rotation axis (Rx) in the side view in a direction away from the opening (116) and the crankcase. A swing unit type power unit characterized in that it is arranged on the outer surface of (28). In the swing unit type power unit according to claim 1 or 2.
A linear reciprocating piston (49) that is coupled to the crankcase (28), is located in front of the crankcase (28), and is connected to the crankshaft (45) by a connecting rod (48) in the vehicle front-rear direction. A cylinder block (29) that guides the movement and
A swing unit arranged behind the crankcase (28) and provided with a rear wheel (WR) having an axle (58) parallel to the rotation axis (Rx) of the crankshaft (45). Expression power unit. In the swing unit type power unit according to claim 3, an oil pan (109) is formed in the crankcase (28) below the crankshaft (45), and the detection sensor (113) is the crankshaft (113). A swing unit type power unit characterized in that it is arranged above 45). In the swing unit type power unit according to claim 4, at least the cylinder block is located on the rotation axis (Rx) extending from one end of the crankshaft (45) and connected to the crankcase (28). A swing unit type power unit characterized by further including a radiator (85) that exchanges heat with the outside air from the cooling water distributed in (29). In the swing unit type power unit according to claim 5,
A first wind guide wall (122) extending in parallel with the rotation axis (Rx) and partitioning a space connected to the opening (116).
With the second wind guide wall (123) that continuously guides the airflow flowing out from the opening (116) toward the rear wheel (WR) following the curved surface from the first wind guide wall (122). Have,
A swing unit type power unit further comprising a wind guide member (119) fixed to an outer surface of the crankcase (28) and covering the detection sensor (113). In the swing unit type power unit according to claim 6, the air guiding member (119) is downward from the air guiding member (119) toward the crankcase (28) behind the detection sensor (113). A swing unit type power unit characterized in that a shielding plate (124) extending to is integrally formed. In the swing unit type power unit according to claim 7, the air guiding member (119) projects outward from the top plate (119a) of the air guiding member (119) facing the outer surface of the crankcase (28). A swing unit type power unit, characterized in that a protruding wall (121) accommodating the upper end of the detection sensor (113) is formed. The swing unit type power unit according to claim 1, has the detected body (103) arranged in an annular shape along the track on the outer periphery, and the crankshaft from the axial direction of the crankshaft (45). An oil sump (106) is formed between the annular plate (102) superposed on (45) and the crankshaft (45) which is continuous from the annular plate (102) toward the rotation axis (Rx). A swing unit type power unit including a cover plate (105) and having a gasket (131) sandwiched between the annular plate (102) and the crankshaft (45). In the swing unit type power unit according to claim 9, the gasket (131) has a bead (137, 138) that is crushed when the annular plate (102) is fastened to the crankshaft (45). A swing unit type power unit featuring. In the swing unit type power unit according to claim 9 or 10, the crankshaft (45) is connected to the oil sump (106) and takes in oil from the oil sump (106) based on centrifugal force. A swing unit type power unit characterized in that a road (107) is formed. In the swing unit type power unit according to claim 11, the crankshaft (45) has a shaft end facing the oil sump (106) and is connected to a connecting rod (48). The crank pin (99) is characterized in that an oil passage (107) and a supply passage (108) extending from the oil passage (107) to the bearing of the connecting rod (48) are formed. Swing unit type power unit.