JP2001080567A - Transmission for motorcycle - Google Patents

Abstract

(57) [Problem] To provide a transmission for a motorcycle capable of realizing a motorcycle having a slim appearance in a narrow vehicle width even when a V-belt type automatic transmission is mounted. SOLUTION: In a transmission of an engine unit for a motorcycle in which a crankshaft 12 and a V-belt type automatic transmission 14 are rotatably supported and housed in an engine case 10, an engine case 10 includes left and right case portions 10L, 10R. Can be divided by combining them with the dividing surface 8.
The outer end of the drive pulley shaft 16 in the direction of
It protrudes outside 0. An outer wall 72a is provided outside the partition 40 in a space with the partition 40, and this space is used as a clutch chamber 72 for accommodating the starting clutch 58. An outer cover body 50 is attached to the engine case 10 with a space outside the outer wall 10a1 of the crank chamber 10a and the outer wall 72a of the clutch chamber, and this space is used as a wet room 38 for accommodating the first reduction gear 32 of reduction gears.
It is what it was.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a motorcycle which comprises a starting clutch comprising an electronic control clutch and a V-belt type automatic transmission (a continuously variable transmission), thereby enabling the motorcycle to be made compact.

[0002]

2. Description of the Related Art Conventionally, motorcycles equipped with a V-belt type automatic transmission often have a small displacement of about 50 to 125 cc, such as a scooter type vehicle, and an engine having a small displacement has a relatively small engine output. Therefore, the clutch mechanism had to be small. On the other hand, in recent years, there has been a demand for an engine unit with a continuously variable transmission that can realize simple driving operation by omitting gear change operation even for motorcycles equipped with a medium to large displacement engine with a large output. Is growing.

[0003]

However, even if a V-belt type automatic transmission is used as the transmission, if the clutch is provided on the output side of the transmission, the size of the clutch increases as the engine output increases. Therefore, a space for installing the clutch is required, and it is inevitable that the size of the engine unit and the size of the vehicle body will increase.

In addition, centrifugal shoe type clutches are often used in conventional V-belt type automatic transmission clutches, and it is necessary to provide a dedicated one-way clutch for effective engine braking. I was invited. After a sudden stop during traveling at the above-mentioned high speed stage, the centrifugal clutch may be disengaged at the time of the stop, and the pulley diameter of the V-belt type automatic transmission may remain at the high speed stage. In some cases, the vehicle starts with the pulley diameter kept at the high-speed stage, which may make it difficult to restart.

On the other hand, the clutch is provided with an electronically controlled wet multi-plate clutch unit for switching between two-wheel drive (2WD) or four-wheel drive (4WD) on the propeller shaft of a four-wheel drive vehicle. (Japanese Patent Laid-Open No. 10-32956)
No. 1), a technique combined with a V-belt type automatic transmission has not been proposed. Even if the clutch unit and the V-belt type automatic transmission are simply combined, even if the space is simply taken to reduce the size of the automatic transmission, there is a technique for obtaining a width by interfering with the engine and for space-efficient arrangement. The fact is that it has not been proposed yet. Therefore, there is a problem that it is difficult to mount a V-belt type automatic transmission on a motorcycle having a slim appearance in a narrow vehicle width.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a motorcycle having a slim appearance with a narrow vehicle width can be realized even when a V-belt type automatic transmission is mounted. It is an object of the present invention to provide a transmission for a motorcycle in which restarting after stopping is easy.

[0007]

The present invention has the following arrangement to achieve the above object. The present invention relates to a transmission for a motorcycle in which a V-belt type automatic transmission is accommodated in an engine case, wherein the engine case has a crank chamber for accommodating a crank web and a dry-type room for accommodating a V-belt type automatic transmission. The crankcase, the dry room, and the partition are divided into right and left so that the crankcase, the dry room, and the partition can be divided, and the starting clutch is housed in the outside of the dry transmission room in the axial direction of the automatic transmission pulley. A transmission for a motorcycle, wherein a clutch chamber is provided, and a space between a crank chamber outer wall and a clutch chamber outer wall and an outer cover is a wet room for accommodating reduction gears. In the present invention, the starting clutch is provided on the drive pulley input side of the V-belt type automatic transmission, and the friction engagement force of the electromagnetic pilot clutch mechanism is converted into the pressing force of the main clutch mechanism by the cam mechanism. Thus, an electronically controlled clutch that controls the main clutch mechanism can be provided. Further, a mechanical clutch for intermittent output can be provided downstream of the V-belt type transmission. Further, the starting clutch can be connected during the period when the mechanical clutch is neutral and the starter motor is energized.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of an essential part showing a state in which an engine unit is mounted on a motorcycle according to an embodiment, FIG. 2 is a side view of an engine case, and FIG.
FIG. 4 is a sectional view taken along the line III-III, FIG. 4 is an explanatory diagram of a pulley and the like of the V-belt type automatic transmission, and FIG. 5 is an explanatory diagram of an electronically controlled electromagnetic starting clutch.

As shown in FIGS. 1 to 4, the embodiment is directed to a transmission for an engine unit for a motorcycle in which a crankshaft 12 and a V-belt type automatic transmission 14 are rotatably supported and housed in an engine case 10. Case 10 is on the left,
The right case portions 10L, 10R are joined together at the dividing surface 8 and fastened and fixed with bolts, so that the vehicle body can be divided in the left-right direction. The engine case 10 includes a crankshaft 12 and a V-belt type automatic transmission 14 therein. A drive pulley shaft 16, a driven pulley shaft 18, and an output shaft 22 that outputs power to the rear wheel 20 are arranged in parallel.

The engine case 10 includes a crank chamber 10a for accommodating a crank web 12a and a dry chamber 36 for accommodating a V-belt type automatic transmission.
Are arranged back and forth by a crankcase 10a
The dry room 36 and the front partition wall 40a are divided into right and left parts that can be divided from the dividing surface 8. The drive pulley shaft 1 of the automatic transmission 14 in the dry chamber 36
Outer end portions in six directions (right end portions in the embodiment) project outside the partition wall portion 40. An outer wall 72a is provided outside the partition 40 in a space with the partition 40, and this space is used as a clutch chamber 72 for accommodating the starting clutch 58. An outer cover body 50 is attached to the engine case 10 with a space outside the outer wall 10a1 of the crank chamber 10a and the outer wall 72a of the clutch chamber, and this space is used as a wet room 38 for accommodating the first reduction gear 32 of reduction gears.
It is what it was.

Further, the starting clutch 58 uses the frictional engagement force of the electromagnetic pilot clutch mechanism 58a by the cam mechanism 5a.
8b, an electronically controlled clutch that converts the pressing force of the main clutch mechanism 58c to control the main clutch mechanism 58c is used (see FIG. 5). Further, a mechanical clutch 8 for interrupting output is provided downstream of the V-belt type transmission 14.
4 is provided. In this case, the mechanical clutch 84
Is neutral, and the start clutch is connected during a period when the starter motor (86) is energized.

This will be described in more detail. In the engine 30, the crankshaft 12, the drive pulley shaft 16 of the V-belt type automatic transmission 14, and the driven pulley shaft 18
Are substantially aligned on the same line slightly downward and obliquely along the tank rail 24b in a side view, and the output shaft 22 is located above the drive pulley shaft 16 and the driven pulley shaft 18.

On the other hand, a reduction gear train 68 of a transmission motor 66 for operating a movable side face (also referred to as a movable sheave) 16b of the drive pulley is disposed above the engine case 10. And, the engine 30 includes the front and rear cylinders 3
0F and 30R are arranged in a V-shape, but the rear cylinder 30R is inclined rearward and rearward on one side of the triangle in a side view.
It is formed with the same backward inclination.

The motorcycle frame 24 includes an upper tank rail 24b extending obliquely downward and rearward from the head pipe 24a, a down tube 24c extending downward from the head pipe 24a and extending horizontally rearward from the middle, and a tank rail. 24b and the rear part of the down tube 24c, and the pivot shaft 26 and the cushion unit 28
And a main frame 24d provided with the main frame 24d. The main frame 24d has a “B” shape in a side view mainly including a portion connecting the rear sides of the down tubes 24c of the tank rails 24b in the vertical direction and a rear portion for placing the seat on the upper portion. I have.

In the engine 30, V-shaped cylinders of a front cylinder and a rear cylinder, each of which has a V-shape inclined forward and backward, are provided at an upper portion of a front portion of the engine case 10. The connecting rods 30b of the pistons 30a of the front cylinder 30F and the rear cylinder 30R are respectively connected. The center position in the length direction of the crankshaft 12 in a state where the crankshaft 12 is disposed in the engine case 10 is a position substantially coincident with the mating surface 8 of the engine case 10 in plan view. The engine case 10 also includes a first reduction gear 32 that inputs the rotation of the crankshaft 12 of the engine 30 to the drive pulley shaft 16 of the V-belt type automatic transmission 14 via a start clutch 58, A second speed reducer 34 that outputs a signal from the driven pulley shaft 18 of the belt-type automatic transmission 14 to the output shaft 22 is arranged on the same side in the longitudinal direction of the crankshaft 12 (right side in the vehicle width direction in the embodiment).

In the engine case 10, the crankshaft 12 is supported by left and right walls of a crank chamber 10a for accommodating the same, and the right wall is the front side of the partition 40. The right end of the crankshaft 12 protrudes from the front side of the partition wall portion 40 which becomes the right side wall of the crank chamber 10a, and the primary drive sprocket gear 42 is disposed at the protruded right end. At the same time, the right end of the drive pulley shaft 16 of the V-belt type automatic transmission 14 is
The shaft is extended from the center in the front-rear direction, and the extended portion enters the clutch chamber 72 and is connected to the secondary side of the starting clutch 58. The primary driven sprocket gear 44 is disposed on the primary side of the starting clutch 58. ing. A chain 46 is wound around the drive sprocket gear 42 and the driven sprocket gear 44, so that the driving force of the engine 30 is transmitted to the V-belt type automatic transmission 14 by the chain 46. Also, the number of teeth of the driven sprocket gear 44 increases, so that the first speed reducer 32 is formed. The first speed reducer 32 is not limited to a chain, and may be combined with an idle gear.

The right end of the driven pulley shaft 18 of the V-belt type automatic transmission 14 protrudes from the rear side of the partition 40, and a secondary drive gear 48a is provided at the protruding right end. The second structure is such that the driving force is transmitted to the secondary driven gear 48b via the idle gear (not shown) to the drive gear 48a.
Is disposed adjacent to the right side surface of the partition wall portion 40. A clutch is provided on the rear right side of the engine case 10 so as to cover the second speed reducer 34 (comprising the drive gear 48a, the idle gear, and the secondary driven gear 48b (which is mounted on the primary side of the output shaft 22)). The outdoor wall 72a is extended, and the clutch outdoor wall 7
A closed wet room 38a is constituted by 2a and the partition 40. On the right front side of the engine case 10, the clutch chamber outer wall 72 a is formed in a tubular shape surrounding the right end of the crankshaft 12. The first reduction gear 32 (comprising the drive sprocket gear 42, the driven sprocket gear 44, and the chain 46 wound around them) is a clutch chamber outer wall 72a.
A cover body 50 is housed in a wet room 38b in which a cover body 50 is detachably fastened and fixed (a mating surface 50a) so as to cover an open portion outside the cylindrical portion. Note that the clutch chamber outer wall 72a is
0 is removably fastened and fixed to the right side surface (the mating surface 7).
2b). An oil seal and a bearing are provided on the drive pulley shaft 16 in a partition (partition wall 40) between the dry chamber 36 and the clutch chamber 72 so that lubricating oil does not enter the dry chamber 36.

A cam chain sprocket gear 52 is provided at the right end of the crankshaft 12 inside a drive sprocket gear 42 and a magneto 54a to be described later, and the chain is wound around the gear 52, and the chain is It is arranged in the chain chamber of the cylinders 30F and 30R. This chain room is a wet room 3
8b, the mist-like lubricating oil in the wet chamber 38 flows into the chain chamber. A magneto 54a and a starter motor gear 54b are provided at the left end of the crankshaft 12 and are covered with a cover body 56 (a mating surface 56a) from the outside.

A secondary driven gear 48b of the second reduction gear 34 is provided on the primary side of the output shaft 22, and the output shaft 2 provided with the mechanical clutch 84 is provided.
On the secondary side, the rotating shaft is changed from the lateral direction to the front-rear direction via the bevel gear 60 to drive the propeller shaft 62 for driving the rear wheels. The output shaft 22 is provided with a mechanical clutch 84 so that the rear wheel drive can be switched on and off at an arbitrary time such as when the vehicle is stopped. This mechanical clutch 84 divides the output shaft 22 in the middle and forms a spline 84a on the outer peripheral surface thereof,
b can be slid in the axial direction by a lever 84c, so that the divided output shaft 22 can be intermittently connected.

The propeller shaft 62 has a rear swing arm 64 having a hollow case shape for supporting the rear wheel 20.
Is loaded inside. At the position of the pivot shaft 26 near the bevel gear 60 at the front of the propeller shaft 62, a connecting portion by a universal joint 62a is provided. At the rear end of the propeller shaft 62, a rotating shaft is attached to the hub of the rear wheel 20 from the front-rear direction. Bevel gears are provided to convert the vehicle in the horizontal direction. Main frame 24d
The lower end of the cushion unit 28 whose upper end is attached to the rear swing arm 64 is connected to the rear swing arm 64 via a link 28a (see FIG. 1).

The V-belt type automatic transmission 14 is a so-called CVT, and as shown in FIG.
Pulley fixed side face 1 on drive pulley shaft 16
A movable face (movable sheave) 16b is spline-coupled to the movable face 16b so as to be movable in the axial direction so as to face the movable face 6a. An actuator motor 66 that changes the drive pulley width (changes the contact radius of the belt) by driving the movable face 16b and a reduction gear train 68 (68a to 68c)
The movable face 16 is provided above the drive pulley shaft 16 in a side view, and is driven by a transmission motor 66.
When the slider mechanism 70 at the rear end b rotates, the movable face 16b moves on the drive pulley shaft 16 to change the pulley width so that the gear can be shifted.
The movement displacement of the movable face 16b is detected by the sensor 70a. A cam spring 1 is provided on the driven pulley shaft 18 so that the width of the driven pulley (the distance between the fixed face 18a and the movable face 18b) can be changed in accordance with the change of the drive pulley width.
8c urges the movable face 18b in the direction of reducing the pulley width (the direction of increasing the pulley diameter). In the V-belt type automatic transmission 14, reference numeral 19
Is disclosed in Japanese Patent Application Laid-Open No. H11-82637 as an example. A large number of blocks formed by coating a metal frame with a phenol resin layer are provided at an endless tension band at a predetermined pitch over the entire length in the longitudinal direction of the belt. This is a V-belt for CVT that can be mounted side by side, does not require lubrication, and can transmit high loads.

The starting clutch 58 is an electronically controlled starting clutch having an electromagnetic pilot clutch mechanism 58a, a cam mechanism 58b and a main clutch mechanism 58c, and its detailed configuration is shown in FIG. That is, the starting clutch 58 is housed in a clutch room 72 formed on the right side of the dry room 36 of the engine case 10 containing the V-belt type automatic transmission 14 (see FIG. 3). In the starting clutch 58, a substantially bowl-shaped front housing 74a, which is an outer rotating member, is located on the input side (the driven pulley shaft 18 output side of the V-belt type transmission), while the front housing 74a is inside the front housing 74a. A shaft 74c integral with a rear housing 74b, which is an inner rotating member located on the periphery, is mounted on the output shaft 22. The main clutch mechanism 58c, the cam mechanism 58b, and the electromagnetic pilot clutch mechanism 58a are arranged in this order from the input side to the output side between the inner peripheral surface of the front housing 74a and the outer peripheral surface of the shaft 74c. In addition,
From the input side to the output side, the main clutch mechanism 58c,
For the cam mechanism 58b and the electromagnetic pilot clutch mechanism 58a, the technology disclosed in JP-A-10-329561 can be appropriately used.

In FIG. 5, reference numerals 76a, 76b, 76
Reference numeral c denotes a bearing. The bearing 76a rotatably supports the front housing 74a with respect to the engine case 10, and the bearing 76b rotatably supports the shaft 74c within the front housing 74a. Inner peripheral surface of front housing 74a and shaft 74
A plurality of clutch plates 58c1 are alternately spline-coupled to the outer peripheral surface c to form a main clutch mechanism 58c. The bearing 76c rotatably supports the rear housing 74b with respect to the engine case 10, and is adjacent to the bearing 76c.
An electromagnetic solenoid 78 is provided so as to surround the outer periphery of 4b. A clutch plate 58a1 of a pilot clutch mechanism 58a is provided behind the electromagnetic solenoid 78, and an armature 80 is provided on the clutch plate 58a1 on the side opposite to the electromagnetic solenoid 78, and an electromagnetic solenoid 78 is provided. Clutch plate 58a1, armature 80,
A magnetic path including the rear housing 74b is formed. The plurality of clutch plates 58a1 are alternately splined to the inner periphery of the front housing 74a and the outer periphery of the control cam 82a of the cam mechanism 58b. The control cam 82a and the main cam 82b of the cam mechanism 58b each have an annular shape, and a plurality of oval grooves having a fixed length are formed in the opposing surfaces in the circumferential direction, and the balls 82c are interposed in the grooves. ing.

When the electromagnetic solenoid 78 is turned on, a magnetic path FL is generated in the cam mechanism 58b, and the cam mechanism 58b frictionally engages the clutch plate 58a1. As a result, the control cam 82a is connected to the front housing 74a via the clutch plate 58a1. As a result, a differential occurs between the control cam 82a and the main cam 82b, and the ball 82c rides over the groove so that the main cam 82b presses the clutch plate 58c1 of the main clutch mechanism 58c to frictionally engage the front housing 74a.
And the shaft 74c are connected. On the other hand, the electromagnetic solenoid 7
When 8 is turned off, both the main clutch mechanism 58c and the pilot clutch mechanism 58a are turned off and disengaged, and the cam mechanism 58b returns to the original position.

According to the embodiment, the rotation of the crankshaft 12 of the engine 30 is transmitted from the first speed reducer 32 in the wet chamber 38b to the drive pulley shaft 16 of the belt-type automatic transmission 14 via the starting clutch 58. And the output after the speed change on the same side as the speed reducer 32 is the driven pulley shaft 1
Come out of 8. A room 36 for accommodating the belt-type automatic transmission 14 is formed integrally with the engine case 10 and has a drive pulley shaft 16 and a driven pulley shaft 18 at left and right walls.
And are supported. Then, the output of the V-belt type automatic transmission 14 is input to the output shaft 22 after being decelerated by the second speed reducer 34 in the wet room 38a again. In this case, an oil seal and a bearing are provided on the partition 40 between the driven pulley shaft 18 and the wet chamber 38a, and the supporting portion of the driven pulley shaft 18 is provided with lubricating oil in the dry chamber 36. Prevent intrusion. Similarly, when the starting clutch 58 is a wet type, an oil seal and a bearing are provided in the partition wall 40 between the dry type room 36 and the clutch room 72 to prevent the lubricating oil from entering the dry type room 36. Is preferred.

The output shaft 22 is provided with a mechanical clutch 84 so that the rear wheel drive can be switched on and off at any time such as when the vehicle is stopped. By employing the mechanical clutch 84, the weight can be reduced at the time of starting or maneuvering of the vehicle, and sudden start can be prevented. In addition, as a condition for starting the engine, the mechanical clutch 48 is neutralized ("disengaged").
State) and the electronically controlled starting clutch 58 is engaged only while the starter motor 66 is energized.

The engine case 10 includes a dry room 36 for accommodating the V-belt type automatic transmission 14, and wet rooms 38b and 38a for accommodating the first and second reducers 32 and 34 requiring lubrication. Are formed separately, the first and second reducers 32 and 34 can be lubricated with the same lubricating oil,
Further, the V-belt type automatic transmission 14 which does not require lubrication can be surely separated from the wet rooms 38a and 38b, so that intrusion of lubricating oil can be prevented. The engine cylinder 30F,
Since the V-belt type automatic transmission 14 is provided substantially at the center of the crankcase 10 in the vehicle width direction in the same manner as the 30R, the V-belt automatic transmission 14 is provided.
The right and left weight balance of the vehicle is good and running stability is improved.
At the same time, the first and second reducers 32 and 3
4 is disposed on the right side in the vehicle width direction of the crankcase, and the magneto 54a, the bevel gear 60, and the like are disposed on the left side in the vehicle width direction, so that the left-right weight balance is further improved.

The engine clutch can be effectively used by engaging the starting clutch 58 provided on the upstream side of the V-belt type automatic transmission 14 at the time of deceleration. Further, by employing the mechanical clutch 84, the weight can be reduced at the time of starting or maneuvering of the vehicle, and a sudden start can be prevented. When the vehicle is suddenly stopped, the V-belt type automatic transmission 14 may stop in the high-speed mode. However, the use of the mechanical clutch 84 makes it easy to restart. That is, as the engine start condition, the mechanical clutch 48 is set to the neutral state ("disengaged" state) and the electronically controlled starting clutch 58 is connected only while the starter motor 66 is energized. At about the same time when the engine is started, the V-belt type automatic transmission 14 returns to the low-speed mode (the pulley diameter changes and the gear can be shifted to the low-speed gear because the belt is fed). There is no starting from middle and high speeds, and starting from low speed stage, there is no backlash.

Further, the V-belt type automatic transmission 14 is used as a multi-plate type starting clutch 58, and the frictional engagement force of the electromagnetic pilot clutch mechanism 58a is converted into the pressing force of the main clutch mechanism 58c by the cam mechanism 58b. By using an electronically controlled clutch that controls 58c, the clutch can be reliably engaged at the time of starting.

The present invention is not limited to the embodiment,
For example, the engine is not limited to a V-type cylinder,
It can be used for various single-cylinder or multiple-cylinder engines.

[0031]

As described above, according to the present invention, the V-belt type automatic transmission is provided substantially at the center of the right and left sides of the crankcase in the width direction of the vehicle as in the case of the engine cylinder. Stability is improved. Further, by engaging the starting clutch provided on the upstream side of the V-belt type automatic transmission at the time of deceleration, the engine brake can be effectively used. In addition, by employing a mechanical clutch, the weight can be reduced at the time of starting or maneuvering of the vehicle, and a sudden start can be prevented. In addition, when the vehicle stops suddenly, the V-belt type automatic transmission may stop in the high-speed mode, but by adopting the mechanical clutch,
Restart is easy. That is, as a condition for starting the engine, the mechanical clutch is neutral ("disengaged" state).
The electronically controlled starting clutch is connected only while the starter motor is energized. As a result, the V-belt type automatic transmission returns to the low speed mode almost simultaneously with the start of the engine (the pulley diameter changes and the gear can be shifted to the low speed stage because the belt is fed). The vehicle can be started from a low-speed stage without starting from a middle and high speed, and there is no delay in restarting.

Electronic control for controlling the main clutch mechanism by converting the frictional engagement force of the electromagnetic pilot clutch mechanism into the pressing force of the main clutch mechanism by a cam mechanism using the V-belt type automatic transmission as a multi-plate type starting clutch. By using a clutch of the type, engagement can be surely performed at the time of starting.

[Brief description of the drawings]

FIG. 1 is a side view of an essential part showing a state in which an engine unit is mounted on a motorcycle according to an embodiment.

FIG. 2 is a side view of the engine unit of FIG. 1 around an engine case.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an explanatory diagram of a configuration of a pulley and the like of a V-belt type automatic transmission.

FIG. 5 is an explanatory diagram of an electronically controlled electromagnetic starting clutch.

[Explanation of symbols]

 Reference Signs List 8 Engine case mating surface 10 Engine case 12 Crankshaft 14 V-belt type automatic transmission 16 Drive pulley shaft 18 Driven pulley shaft 22 Output shaft 30 Engine 32 First reducer 34 Second reducer 36 Dry room 38a, 38b Wet room 40 Partition wall 58 Starting clutch 72 Clutch room 72a Clutch room outer wall

Claims (4)

[Claims] 1. A transmission for a motorcycle in which a V-belt type automatic transmission is accommodated in an engine case, wherein the engine case comprises a crank chamber for accommodating a crank web and a dry room for accommodating a V-belt type automatic transmission. Are arranged in front and rear, separated by a partition, and the crank chamber, the dry room, and the partition are divided into right and left parts, and the starting clutch is housed in the outside of the automatic transmission pulley axial direction of the dry room. A transmission device for a motorcycle, wherein a clutch chamber is provided, and a space between the crank chamber outer wall and the clutch chamber outer wall and the outer cover is a wet room for accommodating reduction gears. The starting clutch is provided on a drive pulley input side of a V-belt type automatic transmission, and converts a frictional engagement force of an electromagnetic pilot clutch mechanism into a pressing force of a main clutch mechanism by a cam mechanism. 2. The transmission according to claim 1, wherein the transmission is an electronically controlled clutch for controlling the main clutch mechanism. 3. The motorcycle transmission according to claim 1, further comprising a mechanical clutch for interrupting the output on a downstream side of the V-belt type transmission. 4. The transmission according to claim 3, wherein the mechanical clutch is neutral, and the start clutch is engaged during a period when the starter motor is energized.