JP4640830B2 - Starter for internal combustion engine - Google Patents

Description

  The present invention relates to a starter for an internal combustion engine in which the starter / power generator starts an internal combustion engine as an electric motor.

In the compression stroke of the internal combustion engine, a large load is applied to the starting motor, and a high load region is obtained immediately before top dead center.
Therefore, in order to start the internal combustion engine, the starting motor is required to have a torque that can overcome this high load range.

The torque necessary for cranking the internal combustion engine and starting the engine is provided by the torque of the motor of the starting motor and the inertial force of the rotating body generated by the cranking.
However, since the torque generated by the motor decreases as the rotational speed increases, the torque and the inertial force are in a trade-off relationship.

  When a starter that rotates the crankshaft via a speed reducer is used as the starter motor, the torque transmitted to the crankshaft is increased by the speed reducer, so even if the cranking speed is reduced, It is possible to sufficiently supplement the torque required for ranking.

  On the other hand, the starter / power generator that starts the internal combustion engine with the rotor, which is a rotating body, directly connected to the crankshaft is a power transmission mechanism that does not use a speed reducer. The value is much smaller than the torque transmitted to the crankshaft, and the dependence on the inertial force increases.

However, if the torque by the motor is simply increased, there arises a problem that the starter / power generator is increased in size.
Even if the cranking speed is increased and the required torque is compensated by the inertial force of the rotating body, the torque transmitted to the crankshaft by the motor is small, so the load in the compression stroke cannot be overcome and the speed increases. The rotation stops before and it becomes impossible to start.

  Therefore, a method of reducing the load in the compression stroke of the internal combustion engine has been conventionally employed in order to reduce the torque necessary for cranking the internal combustion engine (see, for example, Patent Document 1).

JP 2000-283010 A

Conventionally, a reverse decompression device has been used as a method for reducing the load in the compression stroke, including Patent Document 1.
The reverse decompression device disclosed in Patent Document 1 is provided with a decompression cam that rotates on a camshaft of a valve train system to follow the reverse rotation of the camshaft and protrude beyond the outer peripheral shape of the exhaust cam. When the camshaft is reversely rotated, the decompression cam is set to the operating position, and the forward rotation can be started with the exhaust valve lifted, thereby reducing the load on the compression stroke of the internal combustion engine.

However, in the reverse decompression device, the outer shape of the decompression cam returns to the outer peripheral shape of the exhaust cam when the camshaft rotates forward for a while.
Therefore, the starter / power generator is difficult to start unless the internal combustion engine is started before the decompression cam returns to the outer peripheral shape of the exhaust cam.

  The decompression cam returns to the outer peripheral shape of the exhaust cam when the camshaft starts normal rotation by the starter / power generator and passes through the first compression stroke, or at the most after the second compression stroke. There are few opportunities to start the internal combustion engine, sometimes it cannot be started, and the reverse decompression must be applied again before starting.

  The present invention has been made in view of the above points, and an object thereof is to start an internal combustion engine that can reliably start the internal combustion engine by the starter / power generator by using a forward decompression device. The point is to provide the device.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a starter for an internal combustion engine in which the starter / generator, which is a generator that also serves as an electric motor, starts the internal combustion engine as an electric motor. comprising a forward decompression device for releasing the decompression operation state exceeds the number, the starting and power generating apparatus, after the reverse rotation of the crankshaft, have rows starting to rotate in the forward direction, the forward decompression device However, the centrifugal weight for rotating the decompression shaft that acts on the decompression is divided into a main weight and a subweight, and the main weight and the subweight are connected by a connecting rod, and the main weight is connected to the camshaft. Compressed by a torsion spring that is integrally fitted to a decompression shaft that is supported so that it is parallel and eccentric and can rotate relative to the center. The sub-weight is urged in the direction of moving, and the sub-weight is integrated with a sub-shaft that is supported so as to be rotatable relative to a position that is deviated from the decompression shaft by a predetermined angular phase in parallel and eccentric with respect to the cam shaft. The internal combustion engine starting device has a smaller distance from the shaft center of the decompression shaft that is fitted and pivotally supports the main weight to the connecting rod in the decompression operation state than in the decompression release state .

According to a third aspect of the present invention, in the starter for an internal combustion engine according to the first or second aspect , the starter / power generator is coupled to a stator around which a coil is wound and an end of a crankshaft of the internal combustion engine. And an outer rotor that rotates around the outer periphery of the stator.

According to a fourth aspect of the present invention, in the internal combustion engine starter according to any one of the first to third aspects, the engine speed at which the decompression operation state of the forward rotation decompression device is canceled is determined as the starter / power generator. It is characterized by being set higher than the maximum engine speed at the time of cranking by the device.

According to a second aspect of the present invention, in the starter for an internal combustion engine according to the first aspect , the link member has a rod shape, and is axially viewed from the axial direction of the decompression shaft when the camshaft is stopped and when the camshaft is rotated at an extremely low speed. It is in a close proximity position.

According to the starter of the internal combustion engine of the first aspect, by providing the normal rotation decompression device that releases the decompression operation state when the internal combustion engine exceeds the predetermined engine speed, the engine always operates until the predetermined engine speed is exceeded. Since the engine is in the decompression operation state, the internal combustion engine can be reliably started by stable cranking while maintaining the decompression operation state until the internal combustion engine is started by the starter / power generator.
The forward rotation decompression device has a structure in which a centrifugal weight that rotates a decompression shaft that acts on the decompression is divided into a main weight and a subweight, and the main weight and the subweight are connected by a link member. While securing the total weight necessary to stabilize the weight, it is possible to reduce the size of the decompression device by making the weights small and compact, and at the same time, the decompression release speed can be started and generated by stabilizing the weight swing. It can be easily set higher than the maximum engine speed during cranking by the device.
The distance from the shaft center of the decompression shaft that supports the main weight to the connecting rod is smaller in the decompression operation state than in the decompression release state, so the rotational moment of the subweight affects the main weight via the link member. Therefore, it is much easier to set the decompression release rotational speed at which the decompression shaft starts to rotate higher.
Once the decompression shaft rotates, the link member moves away from the decompression shaft, and the ratio of the subweight's rotational moment affecting the main weight via the link member increases, and the total moment of both weights becomes a large value. Even if the engine speed decreases and the engine speed becomes extremely low, the decompression operation speed at which the decompression shaft starts to reversely rotate can be lowered.
Therefore, at the time of starting, the decompression operation state can be maintained for a long time to reduce the capacity of the starter / power generator, and at the time of stoppage, the decompression operation rotational speed can be lowered to the vicinity of the engine stall rotational speed. Even if the adjustment is made, it is possible to avoid the decompression operation during idling.
That is, even if the decompression release speed is set high by the decompression mechanism suitable for the starter of the internal combustion engine by the starter / power generator, the decompression operation speed can be set to a lower speed than the decompression release speed. It is possible to widen the setting range of the idle speed.

  Further, since the forward cranking is started from the light load region after the crankshaft is rotated reversely by the starter / power generator, the inertial force of the piston or the like can be sufficiently utilized, and the startability can be further improved.

According to the starter of the internal combustion engine according to claim 3 , when the starter / generator is made to function as a starter, the torque in the low rotation range is improved by the inertial force of the outer rotor rotating around the outer periphery of the stator, and the greater A starting torque can be obtained.

According to the starter of the internal combustion engine according to claim 4, since the engine speed for releasing the decompression operation state of the normal rotation decompression device is set higher than the maximum engine speed at the time of cranking by the starter / power generator, Even during the maximum output operation of the starter / power generator, the decompressor is in the operating state, and cranking can be performed by maximizing the start torque of the starter / power generator.
Therefore, the internal combustion engine can be started using a smaller starter / power generator.

According to the starter of the internal combustion engine of the second aspect , the link member has a rod shape and is in a close position close to the axis of the decompression shaft as viewed in the axial direction when the camshaft is stopped and when the rotation is extremely low. In this state, the rotation weight of the subweight is unlikely to affect the main weight via the link member. Therefore, it is possible to further easily set the decompression release rotational speed at which the decompression shaft starts to rotate.

  Once the decompression shaft rotates, the link member moves away from the decompression shaft, and the ratio of the subweight's rotational moment affecting the main weight via the link member increases, and the total moment of both weights becomes a large value. Even if the engine speed decreases and the engine speed becomes extremely low, the decompression operation speed at which the decompression shaft starts to reversely rotate can be lowered.

  Therefore, at the time of starting, the decompression operation state can be maintained for a long time, and the capacity of the starting and generating device can be reduced. Even if the adjustment is performed, it is possible to avoid the decompression operation during idling.

  That is, even if the decompression release speed is set high by the decompression mechanism suitable for the starter of the internal combustion engine by the starter / power generator, the decompression operation speed can be set to a lower speed than the decompression release speed. It is possible to widen the setting range of the idle speed.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a scooter type motorcycle 1 according to an embodiment to which the present invention is applied.
The vehicle body front portion 2 and the vehicle body rear portion 3 are connected via a low floor portion 4, and the vehicle body frame forming the skeleton of the vehicle body is generally composed of a down tube 6 and a main pipe 7.

  That is, the down tube 6 extends downward from the head pipe 5 at the vehicle body front portion 2, the down tube 6 is bent horizontally at the lower end and extends rearward below the floor portion 4, and a pair of left and right main pipes 7 at the rear end. The main pipe 7 rises diagonally rearward from the connecting portion, bends horizontally at a predetermined height, and extends rearward.

A fuel tank and a storage box are supported by the main pipe 7, and a seat 8 is disposed above the fuel tank and the storage box.
On the other hand, in the front part 2 of the vehicle body, a handle 11 is provided above and supported by the head pipe 5, and a front fork 12 extends downward and a front wheel 13 is supported at the lower end thereof.

  A bracket 15 projects from the lower end of the rising portion of the main pipe 7, and a swing unit 17 is swingably connected to the bracket 15 via a link member 16.

  The swing unit 17 is mounted with a single-cylinder four-stroke cycle internal combustion engine 30 at the front of the swing unit 17 in a posture in which the cylinder block 32 is largely inclined to a substantially horizontal state. An end portion of a hanger bracket 18 projecting forward from the lower end of the corresponding portion is connected to the link member 16 via a pivot shaft 19.

The belt-type continuously variable transmission 35 is configured from the internal combustion engine 30 to the rear, and the rear wheel 21 is pivotally supported by a speed reduction mechanism 38 provided at a rear portion thereof.
A rear cushion 22 is interposed between the upper end of the speed reduction mechanism 38 and the upper bent portion of the main pipe 7.

  An upper part of the swing unit 17 is provided with a carburetor 24 connected to an intake pipe 23 extending from an upper part of a cylinder head 33 of the internal combustion engine 30 and an air cleaner 25 connected to the carburetor 24.

  On the other hand, a main stand 26 is pivotally attached to the hanger bracket 18 projecting from the lower part of the unit swing case 31, and a kick arm 28 is attached to a kick shaft 27 protruding from the transmission case cover 36 of the belt type continuously variable transmission 35. The kick pedal 29 is provided at the tip of the kick arm 28.

The front part 2 of the vehicle body is covered from the front and rear by the front cover 9a and the rear cover 9b from the left and right sides by the front lower cover 9c, and the center part of the handle 11 is covered by the handle cover 9d.
The floor portion 4 is covered with a side cover 9e, and the vehicle body rear portion 3 is covered with a body cover 10a and a tail side cover 10b from the left and right sides.

FIG. 2 is a cross-sectional view of the swing unit 17 which is cut and developed along the line II-II in FIG.
The unit swing case 31 is configured by combining a left unit case 31L and a right unit case 31R which are divided into left and right parts. The right unit case 31R forms a half of a crankcase part, and the left unit case 31L is It consists of a front and rear crankcase portion 31a, a central transmission case portion 31b, and a rear reduction gear case portion 31c.

  The left open surface of the left unit case 31L is covered with a transmission case cover 36 which is a part of the transmission case, the belt type continuously variable transmission 35 is accommodated therein, and the right open surface of the rear reduction gear case 31c. Is covered with a speed reducer case 37, and a speed reduction mechanism 38 is accommodated therein.

  In the so-called crankcase of the crankcase portion 31a and the right unit case 31R, the crankshaft 40 is rotatably supported by the left and right main bearings 41, 41, and the right extension of the extension portions extending in the left-right horizontal direction is provided. The starter / power generator 60 is provided in the part, and the cam chain drive sprocket 55 and the belt drive pulley 76 of the belt type continuously variable transmission 35 are provided in the left extension part.

In the internal combustion engine 30, a connecting rod 43 connects a piston 42 that reciprocates in a cylinder liner 44 of a cylinder block 32 and a crank pin 40 a of a crankshaft 40.
The four-cycle internal combustion engine 30 employs an SOHC type valve system. A valve mechanism 50 is provided in the cylinder head cover 34, and a cam chain 51 that transmits drive to the valve mechanism 50 includes a camshaft 53. The cam chain chamber 52 is provided in communication with the crankcase portion 31a, the cylinder block 32, and the cylinder head 33.

That is, the cam chain 51 passes through the cam chain chamber 52 between the driven sprocket 54 fitted to the left end of the camshaft 53 oriented in the horizontal direction and the drive sprocket 55 fitted to the crankshaft 40. It is being transported.
In the cylinder head 33, a spark plug 45 is fitted from the opposite side (right side) of the cam chain chamber 52 toward the combustion chamber.

  As shown in FIG. 3, the valve mechanism 50 in the cylinder head cover 34 is largely inclined forward to a state in which the cylinder is almost horizontal, so that an intake valve 56 and an exhaust valve 57 are disposed above and below the camshaft 53. Rocker arms 59i and 59e are pivotally mounted on the upper and lower rocker shafts 58i and 58e, respectively, and the rocker arms 59i and 59e are swung by the rotation of the camshaft 53, and the intake valve 56 is swung at a predetermined timing. The exhaust valve 57 is opened and closed.

A starter / power generator 60 is provided at the right end of the right unit case 31R where the crankshaft 40 protrudes rightward from the right main bearing 41.
Referring to FIG. 2, the starter / power generator 60 includes an inner stator 61 that constitutes a three-phase winding, and an outer rotor that is fitted to the end of the crankshaft 40 of the internal combustion engine 30 and rotates on the outer periphery of the stator 61. 62.

  In the inner stator 61, a stator coil 61b is wound around a yoke 61a fixed to the right unit case 31R. On the other hand, the outer rotor 62 has a hook-like rotor case 62a fitted to the end of the crankshaft 40 and a rotor case. A magnet 62b is fixed to the inner peripheral surface of 62a in the circumferential direction.

At the time of start-up, current flows through the stator coil 61b and magnetic force acts on the outer magnet 62 to rotate the outer rotor 62 to function as an electric motor. The outer rotor 62 rotates the crankshaft 40 together to start the internal combustion engine 30. .
During operation of the internal combustion engine, electric power is generated in the stator coil 61b by rotation of the outer rotor 62 to function as a generator, and the generated electric power is supplied to the battery.

  On the other hand, in the crank case portion 31a of the left unit 31L, the cam chain chamber 52 is formed so as to be separated from the crank chamber by the main bearing 41, and the left side wall of the cam chain chamber 52 is further provided with a belt type stepless on the left side. The partition wall 71 partitions the transmission chamber 70 and the cam chain chamber 52. A circular through hole 71a having a large-diameter flat cylindrical shape through which the crankshaft 40 passes is formed in the partition wall 71, and the through hole 71a is formed in the through hole 71a. An annular seal member 72 is press-fitted, and the crankshaft 40 passes through a hollow portion of the annular seal member 72.

The drive sprocket 55 is fitted on the crankshaft 40 between the seal member 72 and the main bearing 41, and the cam chain 51 is wound around the drive sprocket 55.
This seal member 72 partitions the belt-type continuously variable transmission chamber 70 from the cam chain chamber 52 in a watertight manner to prevent oil from leaking into the belt-type continuously variable transmission chamber 70.
A belt drive pulley 76 is rotatably provided on the crankshaft 40 extending through the seal member 72.

  The belt drive pulley 76 includes a fixed pulley half 77 and a movable pulley half 78. The fixed pulley half 77 is fixed to the left end of the crankshaft 40 via a boss 79 and is movable to the right side thereof. The side pulley half 78 is spline-fitted to the crankshaft 40, and the movable pulley half 78 rotates together with the crankshaft 40 and slides in the axial direction to approach and separate from the fixed pulley half 77. The V belt 75 is sandwiched between the pulley halves 77 and 78 and wound.

  Referring to FIG. 4, a cam plate 80 is provided at a fixed position near the annular seal member 72 on the right side of the movable pulley half 78, and a slide piece 80a provided at the outer peripheral end thereof is connected to the movable pulley. The half plate 78 is slidably engaged with a cam plate sliding boss portion 78a formed in the axial direction at the outer peripheral end of the half body 78.

  The side surface of the movable pulley half 78 on the cam plate 80 side is tapered toward the cam plate 80 side, and a dry weight roller 81 is accommodated between the cam plate 80 inside the tapered surface.

  Therefore, when the rotational speed of the crankshaft 40 increases, the dry weight roller 81 that rotates between the movable pulley half 78 and the cam plate 80 moves in the centrifugal direction due to centrifugal force, and the movable pulley half 78 moves in the same direction. It is pressed by the weight roller 81 and moves to the left to approach the stationary pulley half 77 and moves the V belt 75 sandwiched between the pulley halves 77 and 78 in the centrifugal direction to increase the winding diameter. It is configured as follows.

The rear belt driven pulley 86 corresponding to the belt driving pulley 76 has a stationary pulley half 87 fitted to an inner sleeve 89 that is supported so as to be rotatable relative to the speed reducer input shaft 92 of the speed reduction mechanism 38. A movable pulley half 88 is fitted to an outer sleeve 90 that is slidably supported in the axial direction on the inner sleeve 89 on the left side of the fixed pulley half 87. ing.
The V belt 75 is sandwiched between the pulley halves 87 and 88.

  A centrifugal clutch 91 is provided on the left side of the speed reducer input shaft 92 and the inner sleeve 89. When the rotational speed of the power transmitted to the inner sleeve 89 via the V belt 75 increases, the centrifugal clutch 91 is joined. Is transmitted to the reduction gear input shaft 92.

The speed reduction mechanism 38 transmits the power transmitted to the speed reducer input shaft 92 to the output shaft 94 through the intermediate shaft 93 while reducing the speed by meshing the gears, and the output shaft 94 is the rear wheel 21 axle. This is the rear axle that rotates 21.
A drum brake 95 is provided on the hub portion of the rear wheel 21.

  A transmission case cover 36 covering the belt type continuously variable transmission chamber 70 from the left side covers the belt drive pulley 76 on the front side and the centrifugal clutch 91 on the rear side, and the kick shaft 27 is rotatable slightly forward from the center. A drive helical gear 100 is fitted to the inner end of the kick shaft 27 and is urged by a return spring 101.

Referring to FIG. 4, a sliding shaft 102 is supported coaxially with the crankshaft 40 and is slidable in the axial direction on the inner surface of the front portion of the transmission case cover 36. A driven helical gear 103 is formed and meshed with the driving helical gear 100, and a ratchet wheel 104 is fixed to the right end, and the whole is biased to the left by a friction spring 105.
On the other hand, a ratchet 79 a is formed on the boss 79 on the crankshaft 40 side so as to face the ratchet wheel 105, and both can be brought into contact with and separated from each other by sliding of the slide shaft 102.

  Therefore, when the kick pedal 29 is depressed and the kick shaft 27 rotates against the return spring 101 via the kick arm 28, the driving helical gear 100 rotates together with the kick shaft 27, and the driven helical gear 103 meshing with the driven helical gear 103 is While rotating integrally with the sliding shaft 102, it slides to the right against the friction spring 105, and the ratchet wheel 105 meshes with the ratchet 79 a of the boss 79 to forcibly rotate the crankshaft 40 to cause the internal combustion engine 30 to rotate. Can be started.

  The fixed pulley half body 77 has a rubber cooling fan 118 attached to the side surface (left side surface) opposite to the side surface sandwiching the V-belt 75 by rubber baking. The transmission 35 is cooled.

  The transmission case cover 36 that constitutes the belt type continuously variable transmission chamber 70 is located approximately along the inner surface of the side wall near the belt driven pulley 86 between the belt driving pulley 76 and the belt driven pulley 86 at a substantially central position in the front-rear direction. A rectangular cylindrical exhaust passage 121 is formed so as to bulge and incline slightly obliquely in a substantially vertical direction.

  The exhaust passage 121 has an upper end opening 121t opened in a belt-type continuously variable transmission chamber 70 covered with a transmission case, and a lower end opening opened to the outside. Cooling generated by the rotation of the cooling fan 118 After the wind cools the belt-type continuously variable transmission 35 and removes heat, it is discharged to the outside through the exhaust passage 121.

A normal rotation decompression device 130 is incorporated in the main valve mechanism 50 in the cylinder head cover 34, and the structure thereof will be described with reference to FIGS.
The left and right ends of the camshaft 53 oriented horizontally are supported by bearings 131 and 132, and the decompression shaft 133 is parallel to the camshaft 53 and is eccentric to the left end so that it can rotate relative to the camshaft 53. It is inserted from the surface.

A base end portion 134 a of the main weight 134 is fitted to the left end of the decompression shaft 133.
The main weight 134 has an arm portion 134b extending from the base end portion 134a bulging to the left and is formed thick, and the distal end weight portion 134c rotates in the centrifugal direction from the bulged portion together with the camshaft 53 in the circumferential direction. It is formed by expanding behind the rotation.

  A sector-shaped opening 54a drilled in the driven sprocket 54 secures a region where the portion of the arm portion 134b swings from the base end portion 134a of the main weight 134. At the same time, the sector-shaped opening 54a The swing range is determined.

  Similarly to the decompression shaft 133, the subshaft 135 is inserted into the camshaft 53 from the left end face so as to be parallel and eccentric with respect to the shaft center. It is provided at a position where the 90 degree angular phase is shifted.

A sub-weight 136 is swingably provided with a base end portion fitted to the left end of the sub-shaft 135 that passes through the driven sprocket 54.
The sub shaft 135 extends straight from the base end.

  A protrusion 134d protrudes near the tip of the main weight 134 rotating together with the camshaft 53, while a protrusion 136d protrudes near the tip of the subweight 136 in the rotation direction, and the protrusion 134d and protrusion 136d. A connecting rod 137, which is a link member pivotally supported at both ends, connects the main weight 134 and the subweight 136.

  The main weight 134 is provided with a torsion spring 138. The torsion spring 138 urges the main weight 134 in a direction against the centrifugal force with respect to the swing of the main weight 134 with respect to the camshaft 53.

As shown in FIG. 4, the cylindrical decompression shaft 133 has a substantially half-moon shaped decompression cam portion 133a formed by a notch in the vicinity of the right end, and the vicinity of the decompression cam portion 133a of the camshaft 53 is missing. The decompression cam portion 133a is exposed.
In particular, the region in which the decompression cam portion 133a of the camshaft 53 turns is missing over the entire circumference.

  On the other hand, the rocker arm 59e on the exhaust side rotatably supports a roller 59er in contact with the exhaust side cam portion 53e of the camshaft 53 at the cam side end, and is used for decompression toward the decompression cam portion 133a of the decompression shaft 133. The protrusion 59ed protrudes.

  When the decompression shaft 133 rotates and faces the arc surface on the opposite side of the notch of the half-moon shaped decompression cam portion 133a, the decompression protrusion 59ed swings and compresses the exhaust side rocker arm 59e in contact with the decompression cam portion 133a. In the stroke, the exhaust valve 57 is slightly opened to operate the decompression, and when the decompression projection 59ed faces the notch of the decompression cam portion 133a, the decompression is released without contacting the decompression cam portion 133a.

  The sub shaft 135 is formed with a groove 135a so as not to interfere with the decompression protrusion 59ed.

  FIG. 5 shows a state where the camshaft 53 and the crankshaft 40 are stopped or rotated at an extremely low speed, and the main weight 134 is urged by the torsion spring 138 and swings clockwise to the edge of the fan-shaped opening 54a. The subweight 136 is in the limit position where it is connected to the main weight 134 by the connecting rod 137 and swings clockwise.

  The decompression shaft 133, which is the pivot axis of the main weight 134, swings the exhaust rocker arm 59e with its decompression cam portion 133a contacting the arc surface on the opposite side of the notch toward the decompression protrusion 59ed of the exhaust rocker arm 59e. The decompression operation state is shown.

That is, when the internal combustion engine 30 is stopped or rotates at an extremely low speed, it is in a decompression operation state.
The roller 59er of the exhaust side rocker arm 59e is separated from the base circle of the exhaust side cam portion 53e of the camshaft 53.

In this state, referring to FIG. 5, the connecting rod 137 is axially viewed from the axial center Cm of the decompression shaft 133 which is the center of swing of the main weight 134 (viewed from the side to the right as shown in FIG. 5). ) At the closest proximity.
The distance from the axial center Cm of the decompression shaft 133 to the connecting rod 137 is d.

  A centrifugal force Ps applied to the subweight 136 (indicated by an arrow from the center of gravity Gs of the subweight 136 in FIG. 5) is a force Pc by which the subweight 136 pulls the connecting rod 137 (in FIG. 5, an arrow in a direction in which the connecting rod 137 is directed). And a force Pc · d obtained by multiplying the pulling force Pc by the distance d acts on the main weight 134.

  In the decompression operation state shown in FIG. 5, since the centrifugal force Ps is small due to the extremely low rotation, the force Pc for pulling the connecting rod 137 is also small, and the distance d is the smallest, so the moment Pc · d is small and the subweight. 136 is in a state where it is difficult to affect the swing of the main weight 134, and the main weight 134 does not swing easily against the torsion spring 138 only by the centrifugal force of the main weight 134 alone.

  Even if the rotational speed increases and the centrifugal force Ps increases, the distance d is the shortest. Therefore, the main weight 134 does not swing until the rotational speed exceeds the starting rotational speed and reaches a relatively high rotational speed. It is in.

  Therefore, when the starter / generator 60 is driven as an electric motor, or when the internal combustion engine 30 is started by depressing the kick pedal 29, the decompression is initially activated, the compression in the combustion chamber is released, and the crankshaft 40 is forced to rotate. The internal combustion engine 30 can be started smoothly when the starting rotational speed is exceeded.

  The main weight 134 starts to swing only after the internal combustion engine 30 starts to reach the idling rotational speed, and the main weight 134 starts swinging. Once the main weight 134 starts swinging, as shown in FIG. Since the distance d from the axial center Cm of the decompression shaft 133 to the connecting rod 137 is increased, the moment Pc · d is increased and the subweight 136 greatly affects the swing of the main weight 134. 134 swings to rotate the decompression shaft 133.

  As shown in FIG. 7, when the swing of the main weight 134 reaches the limit of the swing range restricted by the fan-shaped opening 54a formed in the driven sprocket 54, the half-moon-shaped decompression cam portion 133a of the decompression shaft 133 is obtained. The notch is not facing the decompression projection 59ed of the exhaust side rocker arm 59e, and the decompression projection 59ed does not contact the exhaust side rocker arm 59e, the exhaust side rocker arm 59e contacts the roller 59er with the base circle of the cam portion 53e of the camshaft 53, The internal combustion engine 30 enters the normal operating state after being released.

  As described above, since the distance d from the axial center Cm of the decompression shaft 133 to the connecting rod 137 is small at the time of stoppage or extremely low rotation, the rotational moment of the subweight 136 hardly affects the main weight 134 via the link member. Therefore, the decompression release rotational speed at which the decompression shaft 133 starts to rotate can be made as high as possible to maintain the decompression operation state for a long time, so that the internal combustion engine 30 can be started smoothly and reliably.

  In the decompressed state shown in FIG. 7, both the main weight 134 and the subweight 136 are swung in the centrifugal direction around the decompression shaft 133 and the subshaft 135 that are eccentric from the rotation center of the camshaft 53, respectively. These are designed to fit within the outer circumference of the driven sprocket 54, and the main weight 134 and the subweight 136 are compactly configured while ensuring the total weight that does not cause the oscillation to become unstable. Can be miniaturized.

  In this decompression released state, the distance d from the axis Cm of the decompression shaft 133 to the connecting rod 137 is the largest, and the rotational moment of the subweight 136 has a great influence on the main weight 134 via the link member. When the operation of 30 is stopped, the decompression operating rotational speed at which the main weight 134 swings in the reverse direction (rotation center direction) and the decompression shaft 133 starts to reversely rotate can be lowered. It can be lowered to the vicinity.

As described above, the normal rotation decompression device 130 can increase the decompression release rotational speed as much as possible and maintain the decompression operation state for a long time at the time of starting. ing.
Since the maximum engine speed during cranking by the starter / power generator 60 may be lower than the decompression release speed, a small and light starter / power generator 60 can be used.

  The engine speed at the time of cranking of the internal combustion engine 30 when the maximum engine speed at the time of cranking by the starter / power generator 60 is about 900 rpm and the decompression release speed of the forward rotation decompression device 130 is set to 1000 rpm or more. This change is shown in FIG.

Here, immediately after the start of the internal combustion engine, the crankshaft 40 is reversely rotated by the starter / power generator 60 to return to a predetermined forward rotation start angle position, so-called swing back is performed until about 270 msec after the starter switch is turned on. Is rotating the crankshaft 40 in the reverse direction.
Thus, by performing the swing back, the forward cranking can be started from the light load region, and the inertial force of the piston or the like can be fully utilized, and the startability can be further improved.

When the forward rotation cranking starts after about 270 msec, the engine speed increases to over 700 rpm, but when the compression stroke starts, the engine speed decreases and decreases to about 130 rpm at the minimum at about 460 msec. .
The normal rotation decompression device 130 is in the decompression operation state, and the engine speed has increased again after overcoming the first compression stroke P1.

This time, the engine speed reaches about 860 rpm at about 600 rpm, but starts to decrease again after entering the second compression stroke P2.
Since the forward decompression device 130 is in the decompression operation state, the engine speed increases again after overcoming the second compression stroke P2.

  Since the decompression release speed of the forward rotation decompression device 130 is 1000 rpm or more, when the cranking by the starter / generator 60 with the engine speed of 900 rpm or less is always in the decompression operation state, the engine speed is reduced. Each of the compression strokes P1, P2, P3,... Can be overcome, and the internal combustion engine 30 can be reliably started while repeatedly increasing and decreasing the engine speed.

  However, in the case of the conventional reverse decompression device, the decompression operation state is brought about by swingback, and the decompression operation state is maintained at the first compression stroke P1 after entering the forward rotation cranking. P1 can be overcome, but if the internal combustion engine does not start before entering the second compression stroke P2, the decompression is released and the second compression stroke P2 is overcome during the second compression stroke P2. As shown by the broken line in FIG. 8, the rotation is stopped as it is and the engine cannot be started.

  In this way, the reverse decompression device is less likely to start the internal combustion engine, but the forward decompression device 130 is always in the decompression operation state during cranking by the starter / power generation device 60. Even when the engine is repeatedly started and the generated torque as the electric motor is small like the starter / power generator 60, the internal combustion engine can be started reliably.

1 is an overall side view of a scooter type motorcycle according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the internal combustion engine of the scooter type motorcycle cut along line II-II in FIG. 1. It is sectional drawing cut | disconnected along the III-III line | wire in FIG. It is sectional drawing which shows the valve mechanism which the normal rotation decompression apparatus was integrated. It is a side view of the forward rotation decompression device in which the decompression operation state is partially omitted. It is a side view of the forward rotation decompression device in which the decompression is partly omitted in the state of releasing or operating the decompression. It is a side view of the forward rotation decompression device in which the decompression release state is partially omitted. 3 is a graph showing changes in engine speed during cranking of the internal combustion engine 30.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 30 ... Internal combustion engine, 31 ... Unit swing case, 33 ... Cylinder head, 34 ... Cylinder head cover, 40 ... Crankshaft, 50 ... Valve mechanism, 51 ... Cam chain, 53 ... Camshaft, 54 ... driven sprocket, 56 ... intake valve, 57 ... exhaust valve, 58e ... rocker shaft, 59e ... rocker arm,
60 ... Starting and generating device, 61 ... Inner stator, 62 ... Outer rotor,
130 ... Forward decompression device, 133 ... Decompression shaft, 134 ... Main weight, 135 ... Sub shaft, 136 ... Sub weight, 137 ... Connecting rod.

Claims (4)

In the starter of the internal combustion engine in which the starter / generator which is a generator also serving as an electric motor starts the internal combustion engine as an electric motor,
When the internal combustion engine exceeds a predetermined engine speed, a forward rotation decompression device that releases the decompression operation state is provided,
The starting and power generating apparatus, after the reverse rotation of the crankshaft, have rows starting to rotate in the forward direction,
The forward rotation decompression device is configured to divide a centrifugal weight that rotates a decompression shaft that acts on the decompression into a main weight and a subweight, and the main weight and the subweight are connected by a connecting rod,
The main weight is integrally fitted to a decompression shaft that is supported so as to be rotatable relative to the camshaft with its axis parallel and eccentric, and is urged by a torsion spring in a direction in which the decompression is activated.
The subweight is integrally fitted to a subshaft that is parallel and eccentric to the camshaft and is supported so as to be relatively rotatable at a position shifted by a predetermined angular phase from the decompression shaft.
An internal combustion engine starter characterized in that the distance from the axis of the decompression shaft that pivotally supports the main weight to the connecting rod is smaller in the decompression operation state than in the decompression release state . 2. The internal combustion engine according to claim 1 , wherein the connecting rod is in a close position close to the axis of the decompression shaft as viewed in the axial direction of the axis of the decompression shaft when the camshaft is stopped and when the rotation is extremely low. Engine starter. The starting and power generating apparatus, a stator coil is wound, according to claim 1 or claim 2 characterized by having a outer rotor for rotating the outer periphery of the coupled to an end of the crankshaft of the internal combustion engine stator A starter for an internal combustion engine as described. Said engine speed for releasing the decompression operation state of the forward rotation decompression device, any of claims 1 to 3, characterized in that set higher than the maximum engine speed during cranking by the starter and generator device A starting device for an internal combustion engine according to claim 1 .

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