JP4105057B2 - Internal combustion engine with starter motor - Google Patents

Description

  The present invention relates to an internal combustion engine provided with a starter motor.

An example of an internal combustion engine provided with a starter motor is a motorcycle engine. In this type of engine, the starter motor is attached to the AC generator side, that is, the left side of the engine, in the upper part of the upper case of the crankcase. A reduction gear and an idle gear are sequentially displaced inward on the motor rotation shaft of the starter motor. The idle gear meshes with the starter driven gear, and the starter driven gear is connected to the crankshaft via a starter one-way clutch. This starter one-way clutch is arranged coaxially with the crankshaft, for example, between an AC generator and a counterweight. For this reason, the rotation of the starter motor is transmitted to the crankshaft via the reduction gear, the idle gear, and the starter driven gear (see, for example, Patent Document 1).
JP-A-10-238356 (paragraph numbers 0010 to 0016, FIGS. 3, 4, and 5)

However, since this type of engine has the starter one-way clutch arranged on the crankshaft, the crankshaft has a problem that it becomes longer in the axial direction. The longer the crankshaft, the longer the engine in the vehicle width direction. Further, in this type of engine, heavy objects such as an AC generator and a starter motor are easily concentrated on one side, and the weight center of the vehicle body does not coincide with the weight center of the engine.
This invention is made in view of such a subject, and it aims at miniaturizing an internal combustion engine provided with a starter motor. Moreover, it aims at improving the weight balance of an internal combustion engine.

The invention according to claim 1 of the present invention for solving the above-described problems is a cylinder body disposed in a forwardly inclined state on a crankcase, a crankshaft provided in the crankcase, and the crankshaft of the crankshaft. A transmission disposed at the rear, a clutch mechanism disposed at a shaft end portion of the main shaft of the transmission for connecting and disconnecting the rotation of the crankshaft to the main shaft, and a primary drive gear disposed at the crankshaft A primary driven gear disposed on the driving force input side of the clutch mechanism, a starter motor disposed on an upper portion of the transmission and rotating the crankshaft when the engine is started, and disposed on an upper portion of the transmission. A one-way clutch that transmits the driving force of the starter motor in one direction to the crankshaft side. In the engine, the one-way clutch is provided so as to directly input the driving force of the starter motor to the primary driven gear, and the starter motor is closer to the main shaft side than the one-way clutch in the crankshaft direction view. The one-way clutch is disposed closer to the cylinder body than the starter motor.

  According to the internal combustion engine including the starter motor, the starting system components such as the starter motor are disposed on the same side as the clutch mechanism that transmits the rotation of the crankshaft to the transmission. A one-way clutch for a starter motor is disposed above the clutch mechanism, and a starter motor linked to the one-way clutch is disposed in the vicinity of the clutch mechanism. For this reason, the heavy starter motor and the one-way clutch are concentrated on the upper part of the clutch mechanism.

The invention according to claim 2 includes an idle gear interposed between the starter motor and the one-way clutch, and a line connecting the axis center of the crankshaft and the axis center of the main shaft is a front line as viewed in the crankshaft direction. The crankshaft and the main shaft are arranged so as to be lowered, and the one-way clutch is connected to the cylinder main body side and the idle gear is connected to an orthogonal line orthogonal to this line and passing through the axis center of the starter motor. It is arranged on the opposite side to the cylinder body .

The invention according to claim 3 includes an idle gear interposed between the starter motor and the one-way clutch, wherein the starter motor, the one-way clutch, and the idle gear are in the front-rear direction and the axial center of the crankshaft and the axial center of the main shaft It is arrange | positioned between.
According to a fourth aspect of the present invention, the internal combustion engine is an in-line four-cylinder engine, and the starter motor is disposed so as to straddle a left and right crank bearing between the second and third cylinders.

According to the present invention , the starter motor, the one-way clutch, and the clutch mechanism are arranged on the same side of the engine, the one-way clutch is arranged on the upper part of the clutch mechanism, and the starter motor is arranged in the vicinity of the clutch mechanism. Therefore, the heavy starter motor and the one-way clutch can be concentrated on the upper part of the clutch mechanism.
For this reason, the weight center of an internal combustion engine and the center of the vehicle body in which such an internal combustion engine is mounted can be brought close. Further, the axial length of the crankshaft can be shortened and the width of the internal combustion engine can be reduced as compared with the configuration in which the one-way clutch is disposed on the crankshaft.
According to the present invention , since the heavy starter motor is disposed inside the internal combustion engine with respect to the clutch mechanism, the starter motor, the one-way clutch, and the idle gear can be disposed inside the clutch mechanism, and the weight center of the internal combustion engine can be achieved. Can be concentrated in the center.

  The best mode for carrying out the invention will be described in detail with reference to the drawings. In the following, the front side is the forward direction of the vehicle, and the rear side is the direction in which the vehicle moves backward. Further, the right side and the left side are the right side and the left side in the direction in which the vehicle advances.

As shown in FIG. 1, the front wheel 2 of the motorcycle 1 is pivotally supported by a front fork 3, and the front fork 3 is steered by a head pipe 6 provided at a front end portion of a vehicle body frame 5 via a top bridge 4. It is pivoted as possible. The rear wheel 7 of the motorcycle 1 is pivotally supported by a rear fork 8, and the rear fork 8 is pivotally supported by a pivot portion 9 and an engine 15 provided at an intermediate portion of the vehicle body frame 5. The upper end of the rear cushion unit 10 is attached to the vicinity of the pivot shaft of the rear fork 8, and the lower end of the rear cushion unit 10 is attached to the lower part of the engine 15 via the link mechanism 11. The shock is absorbed so that no impact is applied to the vehicle body via
From the upper part of the head pipe 6, the main frame 12 of the vehicle body frame 5 is divided into left and right parts and extends rearward and downward, and the rear end part thereof is bent downward and continues to the pivot part 9. A seat rail 13 of the vehicle body frame 5 is connected to the rear of the main frame 12. A fuel tank 14 is disposed above the main frame 12, and an engine 15 is disposed below the main frame 12.

A driver's seat 16 and a rear passenger's pillion seat 17 are respectively supported by the seat rails 13 behind the fuel tank 14. A driver step 18 is attached to the rear portion of the pivot portion 9 of the main frame 12, and a rear passenger step 19 is attached to the lower portion of the seat rail 13. Further, a pair of left and right handles 20 are attached to the upper end portion of the front fork 3.
A brake caliper 21 is attached to the lower end of the front fork 3, and a brake rotor 22 corresponding to the brake caliper 21 is attached to the front wheel 2 to constitute a front brake device 23. A rear brake device (not shown) having the same configuration as the front brake device 23 of the front wheel 2 is provided on the right side of the rear wheel 7.
The front part of the motorcycle 1 is covered with a front cowl 24, and the periphery of the seat rail 13 is covered with a rear cowl 25. A rear sprocket 26 is attached to the left side of the rear wheel 7, and a drive chain 28 is wound around the rear sprocket 26 and a drive sprocket 27 disposed on the left side of the rear portion of the engine 15 to drive the engine driving force to the rear wheel 7. Can be communicated to. A retractable side stand 29 is disposed at the lower left side of the vehicle body frame 5 and can support the motorcycle 1 in a standing state in which the vehicle body is inclined to the left.

  The engine 15 of the present embodiment is a water-cooled in-line four-cylinder engine, and the cylinder body 30 is disposed on the crankcase 31 in a slightly inclined state. A throttle body 32 corresponding to each cylinder is connected to a rear portion of the cylinder body 30, and each throttle body 32 is connected to an air cleaner case 33 disposed between the main frame 12 and the fuel tank 14. An exhaust pipe 34 corresponding to each cylinder is connected to the front portion of the cylinder body 30. The exhaust pipe 34 curves downward from the front wall of the cylinder body 30, passes through the crankcase 31, and then bends upward at the rear of the pivot portion 9 to connect to the silencer 35 supported by the seat rail 13. Is done.

  A radiator 36 is disposed in front of the exhaust pipe 34 with a slightly forward tilted attitude similar to the cylinder body 30. The radiator 36 is a round type whose front side is curved in a concave shape, and is a cross-flow type in which a cooling water inflow side tank is provided on the right side of the radiator core and an outflow side tank is provided on the left side. Is provided so as to extend from the upper part of the crankcase 31 to the lower part of the crankcase 31. A pair of left and right radiator fans 39 (see FIG. 1) are attached to the upper back side of the radiator core.

  As shown in the left side view of FIG. 2 and the right side view of FIG. 3, the engine 15 includes a cylinder head 40, a cylinder block 43, and a crankcase 31 that are main components. The cylinder head 40 is divided into a head body 41 and a head cover 42, and the crankcase 31 is divided into an upper case 44 and a lower case 45. The upper case 44 and the cylinder block 43 are integrally formed, and an oil pan 46 is attached under the lower case 45. Here, the head main body 41 is a cast product made of an aluminum alloy.

  A spark plug 70 is screwed into the head body 41 of the cylinder head 40 so as to face each combustion chamber, and an intake port 71 and an exhaust port 72 are formed to communicate each combustion chamber with the outside. A throttle body 32 is connected to the opening on the outside of each intake port 71, and an exhaust pipe 34 is connected to the opening on the outside of each exhaust port 72. In addition, valve seats are respectively attached to the openings on the combustion chamber side of the intake ports 71 and the exhaust ports 72, and these openings can be opened and closed by the operation of the intake valves 75 and the exhaust valves 76.

  Above each intake valve 75 and exhaust valve 76, an intake side camshaft 85 and an exhaust side camshaft 86 that actuate them are arranged in parallel with the axis C of the crankshaft 47. On the peripheral surfaces of the intake side camshaft 85 and the exhaust side camshaft 86, intake side cams and exhaust side cams (not shown) corresponding to the intake valves 75 and the exhaust valves 76 are provided.

  In addition, cam sprockets (not shown) are provided at the right ends of the camshafts 85 and 86, respectively, and the camshafts 85 and 86 are linked to the crankshaft 47 through cam chains wound around the cam sprockets. . As the crankshaft 47 rotates, the camshafts 85 and 86 rotate, so that the intake valve 75 and the exhaust valve 76 can be operated. The camshafts 85 and 86 are hollow, and the hollow portion serves as a passage for engine oil (lubricating oil) L, and the engine oil L is supplied to each sliding surface from a predetermined oil hole.

  As shown in FIGS. 2 and 3, four cylinders 50 are formed in the cylinder block 43 side by side in the vehicle body width direction. Further, pistons 51 are slidably fitted in these cylinders 50. A connecting rod 53 is rotatably connected to each piston 51 via a crank pin 54, and a large end portion of the connecting rod 53 is rotatably connected to a crank pin 54 of a crankshaft 47, and the reciprocating motion of the piston 51 is an axis. It is converted into a rotational motion around C.

  An oil pump 89 that pumps the engine oil L to an appropriate location in the engine 15 is disposed below the crankcase 31. The oil pump 89 is linked to the oil pump drive sprocket 128 that rotates together with the main shaft 192 of the transmission 164 via the chain 129, and starts to operate as the crankshaft 47 rotates. Engine oil L is stored in an oil pan 46 fixed to the lower portion of the lower case 45, and an oil strainer 130 is immersed in the stored engine oil L.

  The upper end of the oil strainer 130 is connected to the suction port of the oil pump 89, and the discharge port of the oil pump 89 is connected to a first oil passage 133 formed in the lower case 45. The first oil passage 133 extends upward from the discharge port of the oil pump 89 and then bends forward, extending slightly forward and extending forward. A cartridge type oil filter 134 is detachably attached to the front wall 196 of the lower case 45. The oil filter 134 can be detached from the side of the engine 15. The engine oil L flows into the oil filter 134 from the oil inflow path 136, flows out of the oil outflow path 137, and is guided to the water-cooled oil cooler 65.

  The above-described water-cooled oil cooler 65 is disposed substantially at the center of the front wall 196 of the crankcase 31, and an oil filter 134 is attached to the right side of the water-cooled oil cooler 65. The water-cooled oil cooler 65 is attached to the front portion of the lower case 45 that constitutes the crankcase 31, and cools the engine oil L flowing through the interior thereof with cooling water. The cooling water is introduced from an introduction hose 68 attached to the oil pump 89. The cooling water after flowing through the water-cooled oil cooler 65 to cool the engine oil L is returned to the water pump 55 (see FIG. 3) attached to the right side wall 43a of the cylinder block 43 via the outlet hose 67. .

  The water pump 55 is attached to the right side wall 43 a of the cylinder block 43 of the engine 15. The position of the water pump 55 is between the cylinder center line SC that is the center axis of the cylinder 50 and the transmission 164 that includes the shift drum 123 disposed behind the crankcase 31. A cooling water introduction hose 58 that introduces cooling water from the radiator 36 and a bypass hose 64 are connected to the water pump 55. The water pump 55 is driven as the crankshaft 47 rotates, and the cooling water pumped from the water pump 55 flows into the cylinder-side water jacket 57 from a cooling water inlet (not shown) provided on the right side of the cylinder block 43. Then, it flows out from the cooling water outlet 61 provided in the head side water jacket 60 at the rear of the cylinder head 40. A part of the cooling water to be pumped is supplied to the water-cooled oil cooler 65 through the introduction hose 68.

Referring to FIG. 5, the outlet of the water-cooled oil cooler 65 is formed in the second oil passage 140 that is formed in the lower case 45 and slightly rises rearward and extends rearward substantially parallel to the first oil passage 133. Connected. The second oil passage 140 communicates with a main oil gallery 173 and an oil jet (not shown) in the engine 15.
The engine oil L supplied into the engine 15 is returned and stored in the oil pan 46 by natural dripping or the like. The engine oil L is supplied again into the engine 15 through the oil strainer 130, the oil pump 89, the oil filter 134, and the water-cooled oil cooler 65, and circulates in the engine 15. Note that the hydraulic pressure of the engine oil L that is pumped increases when the engine rotates at a high speed. When this hydraulic pressure reaches a predetermined value, the relief path 141 is located below the intersection of the first oil path 133 and the oil inflow path 136. The oil relief valve 142 connected via the is operated. A part of the engine oil L flows back into the oil pan 46, and the hydraulic pressure in the path is adjusted.

  Further, referring to FIG. 3, in crankcase 31, crankshaft 47 is disposed on the front side with an axis C parallel to the vehicle body width direction, and clutch mechanism 163 and transmission 164 are disposed on the rear side. Is done. In addition, a starting system component such as a starter motor 107 is disposed above the transmission 164 so that the crankshaft 47 can be rotated when the engine is started.

The arrangement of the crankshaft 47 and the starter motor 107 will be described in more detail with reference to FIGS. 4 is a cross-sectional view taken along line AA in FIG.
First, the crankshaft 47 is disposed in the crankcase 31 and has a crank pin 54 that rotatably connects a connecting rod 53 (both see FIG. 2) of the piston 51 along the vehicle body width direction. Since the engine 15 is an in-line four-cylinder type, the crankshaft 47 includes four crankpins 54. Each crank pin 54 is supported by a pair of crank arms 169. Each crank arm 169 is integrally formed with a counterweight 169 a at a portion opposite to the crankpin 54. Five journal portions 170 provided on the axis C between both ends of the crankshaft 47 and the crank arms 169 are rotatably supported by bearings 171 provided in the upper case 44 and the lower case 45. A generator serving as a generator is disposed at the left end of the crankshaft 47 and covered with a generator cover 126. A driving sprocket 147 for the water pump 55 and a driving sprocket 149 for rotating the camshafts 85 and 86 are fixed to the outer side of the journal portion 170 at the right end of the crankshaft 47 in this order from the inner side in the vehicle width direction. . Further, a crank pulsar plate 148 having a large number of teeth is attached to the outer side in the vehicle width direction than the driving sprocket 149 so that the rotation speed of the crankshaft 47 can be detected by cooperating with a sensor (not shown). It has become.

  A primary drive gear 189 is provided on the outer periphery of the left crank arm 169 that supports the rightmost crank pin 54 and the counterweight 169a that is integrally formed therewith, and this primary drive gear 189 is arranged on the right side of the crankcase 31. It meshes with the primary driven gear 190 of the clutch mechanism 163 provided. The clutch mechanism 163 includes a primary driven gear 190, a clutch outer 191 that rotates integrally with the primary driven gear 190, a clutch center 193 that is housed in the clutch outer 191 and rotates integrally with the main shaft 192 of the transmission 164, and the clutch outer 191 side. And a plurality of friction plates 191a, 193a,... On the clutch center 193 side.

  A pressure plate 195 urged by a plurality of clutch springs 194 is attached to the clutch center 193, and the friction plates 191a... 193a. It becomes a state that can be transmitted.

  The starter motor 107 is attached to the upper part of the upper case 44 and on the inner side in the vehicle width direction than the clutch mechanism 163, and has a configuration in which a rotating shaft 108 that rotates by power feeding from a battery extends from the central axis of a cylindrical body. Have. The rotating shaft 108 is arranged in parallel with the crankshaft 47, and the tip thereof is close to the primary driven gear 190. The starter motor 107 has a main body located near the center of the engine 15 and close to the clutch mechanism 163 so as to partially overlap the side view (see FIG. 3).

  The outer circumference of the rotary shaft 108 is processed into a tooth shape, and meshes with the large-diameter gear 109 a of the idle gear 109. The large-diameter gear 109 a is fixed to the shaft 109 b, and the shaft 109 b is pivotally supported above the upper case 44 relative to the rotating shaft 108 of the starter motor 107. A small-diameter gear 109c is provided on the right side of the engine 15 with respect to the shaft 109 relative to the arrangement position of the large-diameter gear 109a. The small diameter gear 109 c meshes with the first reduction gear 111 of the reduction gear 110. The reduction gear 110 has a first reduction gear 111 and a second reduction gear 112 having a diameter smaller than that of the first reduction gear 111 and realizes a predetermined gear ratio. The second reduction gear 112 is disposed on the right side of the engine 15 with respect to the first reduction gear 111, and a starter one-way clutch 113 is interposed between the two gears 111 and 112. Second reduction gear 112 meshes with primary driven gear 190.

  The starter one-way clutch 113 is also referred to as an overrunning clutch. The starter one-way clutch 113 is fixed to the first reduction gear 111 and has a cylindrical shape, and is disposed so as to cover the outer periphery of the inner member 114. The outer member 115 is provided, and a roller 116 and a spring (not shown) are interposed between the inner member 114 and the outer member 115 so that the connection between the inner member 114 and the outer member 115 can be interrupted. The inner member 114 is fixed to the shaft 117 and rotates together with the first reduction gear 111 and the shaft 117. The outer member 115 can rotate relative to the inner member 114 and the shaft 117, and the second reduction gear 112 is fixed to one end thereof. The roller 116 comes into contact with only the inner member 114 or the outer member 115 from a position where the roller 116 comes into contact with the inner member 114 and the outer member 115 to connect the inner member 114 and the outer member 115. It is possible to move between positions where the connection with 115 is released. The spring biases the roller 116 in a direction to release the engagement between the inner member 114 and the outer member 115. Here, as shown in FIG. 3, the shaft 117 is attached to the upper case 44 in parallel with the crankshaft 47 at a position on the upper side of the clutch mechanism 163 and on the front side of the starter motor 107. , Located above the clutch mechanism 163.

  Referring to FIG. 4, when inner member 114 starts rotating, roller 116 rolls against the biasing force of the spring. Thereby, the inner member 114 and the outer member 115 are connected via the roller 116 and rotate in the same direction. On the other hand, when the outer member 115 rotates in the opposite direction, or when the rotation speed of the outer member 115 becomes larger than the rotation speed of the inner member 114 by a predetermined amount, the roller 116 is pushed back by the outer member 115 and the spring. Thereby, the connection between the inner member 114 and the outer member 115 is released, and the outer member 115 idles with respect to the inner member 114. A sprag may be used instead of the roller 116. In this case, when the engine 15 is started, the sprag rises with respect to the outer periphery of the inner member 114 to connect the inner member 114 and the outer member 115. When the rotational speed increases after the engine 15 is started, the sprag lies down along the outer periphery of the inner member 114 and the outer member 115 idles with respect to the inner member 114.

  The starter motor 107, the idle gear 109, and the reduction gear 110 (including the starter one-way clutch 113), which are the starting system parts of the engine 15, have the shafts 108, 109b, 117, the rotation centers of the crankshaft 47 and the primary driven gear 190 ( It is located above the main shaft 192) of the transmission 164, and the shafts 108, 109b, 117 are arranged between the crankshaft 47 and the main shaft 192 in the front-rear direction. When the engine 15 is started, the starter motor 107 is driven, and the rotation of the rotary shaft 108 is transmitted to the reduction gear 110 disposed further forward via the idle gear 109 located above. In the reduction gear 110, the inner member 114 rotates as the first reduction gear 111 rotates. When the roller 116 rolls according to this, the inner member 114 and the outer member 115 are connected, and the outer member 115 rotates together with the inner member 114. As a result, the second reduction gear 112 also rotates, and the rotation decelerated at a predetermined speed ratio is transmitted to the primary driven gear 190 disposed below and behind the reduction gear 110. When the primary driven gear 190 rotates, the crankshaft 47 starts to rotate via the primary drive gear 189, and the engine 15 starts.

  On the other hand, after the engine 15 is started, the rotation of the crankshaft 47 is transmitted from the primary drive gear 189 to the primary driven gear 190, and the main shaft 192 is rotated via the clutch mechanism 163. At this time, the second reduction gear 112 of the reduction gear 110 that is meshed with the primary driven gear 190 and the outer member 115 connected thereto are also rotated by the primary driven gear 190. When the starter motor 107 is stopped, the difference in rotational speed between the inner member 114 interlocked with the rotating shaft 108 and the outer member 115 rotated by the primary driven gear 190 increases, and the inner member 114 The connection of the outer member 115 is released. As a result, the outer member 115 idles, so that the rotation of the crankshaft 47 is not transmitted to the starter motor 107.

  As shown in FIG. 3 and FIG. 5 which is a sectional view taken along line BB in FIG. 3, the transmission 164 is arranged in parallel with the axis C and is rotatably supported by the crankcase 31. The shaft 192 and the counter shaft 198 shown in FIG. 3 (both are spline shafts), the transmission gear group 199 provided on each of the shafts 192 and 198 and fitted to each other by spline, and the transmission gear group 199, A shift drum 123 and a shift fork 124 are provided to control the meshing gears. The main shaft 192 is coaxially arranged with the clutch mechanism 163, and the clutch center 193 of the clutch mechanism 163 is fitted and fixed to the right end portion of the main shaft 192. The shift fork 124 has one end engaged with a groove formed on the outer periphery of the shift drum 123 and the other end engaged with a specific gear of the transmission gear group 199. 8 shows only the shift fork 124 engaged with the main shaft 192 side, the transmission 164 also includes a shift fork engaged with the counter shaft 198 side. When the gear position is switched, the shift drum 123 is rotated by the driver's operation, and the shift fork 124 slides in the width direction of the engine 15 along with this, and the specific gears constituting the transmission gear group 199 are slid. To engage the gear or to disengage the gear.

The driving force generated by the engine 15 is transmitted from the crankshaft 47 to the main shaft 192 of the transmission 164 via the primary drive gear 189, the primary driven gear 190, and the clutch mechanism 163. Further, it is transmitted to the countershaft 198 (see FIG. 3) at a predetermined speed ratio via the transmission gear group 199 and is fixed to the left end portion of the countershaft 198 from the drive sprocket 27 (see FIG. 1) via the drive chain 28. To the rear wheel 7.
On the other hand, when the shift drum 123 is operated, the clutch release 200 disposed on the left side of the crankcase 31 is operated, and the pressure plate 195 is attached to the clutch spring 194 via the rod 197 inserted into the main shaft 192. Moved against power. As a result, the two friction plates 191a... 193a.

  In addition, a secondary balancer 185 is disposed at the front portion of the crankcase 31 and slightly to the left of the vehicle width direction central portion. The secondary balancer 185 is housed in a housing portion 186 formed by a part of the lower case 45 bulging forward. As shown in detail in FIG. 4, the secondary balancer 185 has a configuration in which the balancer weight 213 is fixed to the outer periphery of the balancer shaft 210 pivotally supported by the housing portion 186 with thrust washers 211 and 212. A balancer driven gear 215 is attached to one end via a damper rubber 214. The balancer driven gear 215 meshes with a balancer drive gear 187 formed on the crankshaft 47. The balancer drive gear 187 is formed on the outer peripheral portion of a counterweight 169a formed integrally with the crank arm 169 that supports the second crank pin 54 from the left side.

  Reference numerals 172, 173, 174, 175, 176, and 177 indicate the path of the engine oil L. The oil groove 172 is formed at a substantially central portion in the axis C direction on a receiving surface that supports the peripheral surface of the journal portion 170 in each bearing 171. The main oil gallery 173 is formed in the lower case 45 in the vehicle body width direction over the vicinity of both ends of the crankshaft 47. The oil path 174 connects the main oil gallery 173 and the oil groove 172 of each bearing 171, and the engine oil L is supplied from the main oil gallery 173 to each bearing 171 via the oil path 174 and the oil groove 172. The The oil holes 175 penetrate the portions of the four journal portions 170 excluding the rightmost side facing the oil groove 172 of the bearing 171 in the radial direction. The oil hole 176 penetrates substantially the center portion in the axial direction of the crank pin 54 in the radial direction. The communication oil hole 177 is formed in the crankshaft 47 and allows the oil hole 175 and the oil hole 176 to communicate with each other. A part of the engine oil L supplied to the oil groove 172 through the oil hole 175, the communication oil hole 177, and the oil hole 176 is supplied to the peripheral surface of each crank pin 54. The opening of the communication oil hole 177 formed in the crank arm 169 is closed by press-fitting a steel ball or the like.

  The main shaft 192 and the counter shaft 198 of the transmission 164 shown in FIG. 3 are both made of a hollow body, and engine oil L flows through the hollow portion through the oil holes and the respective sliding surfaces, the transmission gear group 199 (FIG. 5). Engine oil L is supplied to the clutch mechanism 163 and the like. Similarly, the camshafts 85 and 86 shown in FIG. 2 are also made of a hollow body, and the engine oil L flows through the hollow portions, and the engine oil L is supplied to the sliding surfaces from the oil holes or the like.

As shown in FIG. 4, according to the embodiment, the starter motor 107, which is a heavy object, is arranged at the center in the width direction of the engine 15, so the center of weight of the engine 15 is near the center in the width direction. Further, since the starter motor 107 is disposed near the center in the front-rear direction of the engine 15, the center of weight of the engine 15 is near the center in the front-rear direction. From this, the weight center of the engine 15 can be brought close to the center of the vehicle body, and the motion performance of the vehicle can be improved.
In addition, since the starter one-way clutch 113 is provided in the reduction gear 110, the axial length of the crankshaft 47 can be shortened as compared with the case where a similar one-way clutch is provided in the crankshaft 47. Therefore, the width of the engine 15 in the left-right direction can be reduced, and the turning performance of the vehicle is improved. Here, since the starter motor 107 is arranged in the space near the clutch mechanism 163, the empty space of the engine 15 can be used effectively, and the gear train connecting the starter motor 107 and the crankshaft 47 is compactly arranged. The engine 15 can be reduced in size. In this way, by arranging the starting system parts closer to the center of the engine 15, the starting system parts are protected by peripheral parts such as the cylinder block 43 and the transmission 164.

The present invention is not limited to the above-described embodiment. For example, an engine having a plurality of cylinders arranged in the vehicle body width direction may not be an in-line four-cylinder type, and may be a parallel type engine. Furthermore, the present invention is not limited to motorcycles, and can be applied to vehicles such as three-wheel and four-wheel vehicles or ships.
Further, the reduction gear 110 and the starter one-way clutch 113 may be configured separately.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a left view of an engine. It is a right view of an engine. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG.

Explanation of symbols

15 Engine 31 Crankcase 47 Crankshaft 107 Starter motor 109 Idle gear 110 Reduction gear (reduction gear)
113 One-way clutch for starter (one-way clutch)
163 Clutch mechanism 192 Main shaft (shaft)
198 Counter shaft (shaft)

Claims (4)

A cylinder main body disposed in a forward inclined state on the crankcase, a crankshaft provided in the crankcase, a transmission disposed behind the crankshaft, and a main shaft of the transmission; A clutch mechanism disposed at a shaft end portion for connecting / disconnecting rotation of the crankshaft to / from the main shaft; a primary drive gear disposed at the crankshaft; and a primary driven gear disposed at a driving force input side of the clutch mechanism; A starter motor which is arranged on the upper part of the transmission and rotates the crankshaft when the engine is started, and a one-way which is arranged on the upper part of the transmission and transmits the driving force of the starter motor in one direction to the crankshaft side. An internal combustion engine comprising a clutch,
The one-way clutch is provided so as to directly input the driving force of the starter motor to the primary driven gear, and the starter motor is disposed closer to the main shaft side than the one-way clutch in the crankshaft direction view, An internal combustion engine comprising a starter motor, wherein the one-way clutch is disposed closer to the cylinder body than the starter motor. Comprising an idle gear interposed between the starter motor and the one-way clutch;
The crankshaft and the main shaft are arranged so that a line connecting the axis center of the crankshaft and the axis center of the main shaft is forwardly lowered when viewed from the crankshaft direction. 2. The starter motor according to claim 1 , wherein the one-way clutch is disposed on the cylinder body side and the idle gear is disposed on the opposite side of the cylinder body with respect to an orthogonal line passing through a motor shaft center. Internal combustion engine equipped with. Comprising an idle gear interposed between the starter motor and the one-way clutch;
3. The starter motor according to claim 1, wherein the starter motor, the one-way clutch, and the idle gear are disposed between an axis center of the crankshaft and an axis center of the main shaft in the front-rear direction. Internal combustion engine. The internal combustion engine is an in-line four-cylinder engine;
The internal combustion engine provided with the starter motor according to any one of claims 1 to 3, wherein the starter motor is disposed so as to straddle a left and right crank bearing between the second and third cylinders.

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