JPH02249787A - Motorcycle provided with swing type power unit - Google Patents

Abstract

PURPOSE:To improve maintainability and workability preventing lubricating oil leakage by constituting a transmission case by connecting right and left cases, forming a belt transmission chamber in one of the width direction both sides and a gear transmission chamber in the other respectively in an opposite direction in the left side case and coating an opening surface of both the chambers with a cover. CONSTITUTION:A transmission case C is constituted of a left side case Cl integrally formed with the left half of a crankcase part 6 and a right side case Cr integrally formed with the right half of the crankcase part 6. The left side case Cl coats its left side opening surface 9 with a transmission case cover Co and the right side opening surface 10 with a transmission case cover Cm. While a side of the opening surface 9 forms a belt transmission chamber 33 housing a crankshaft 13 and a belt transmission gear Mv. On the contrary, a side of the opening surface 10 forms a gear transmission chamber 43, in a direction mutually opposite to the belt transmission chamber 33, housing a gear reduction gear mechanism G. By this constitution, the leakage of lubricating oil to the belt transmission chamber can be prevented.

Description

[Detailed Description of the Invention] A1 Objective of the Invention (1) Industrial Application Field The present invention provides a power unit in which an engine and a transmission device with driving wheels mounted on an axis can be vertically swung on a vehicle body frame. This invention relates to a suspended motorcycle equipped with a swing-type power unit.

(2) Prior Art Conventional motorcycles equipped with the above-mentioned swing type power unit are disclosed in, for example, Japanese Utility Model Application Publications No. 162642/1980 and No. 160946/1989.

(3) Problems to be Solved by the Invention In such motorcycles, a belt transmission device such as a belt-type continuously variable transmission and a gear reduction mechanism are generally housed in the power unit, and the engine Φ output is transmitted through the belt transmission device and gear reduction mechanism. The transmission is transmitted to the rear wheels, that is, the drive wheels, via the gear reduction mechanism, and the mating surface of the transmission case cover that houses the gear reduction mechanism to the transmission case is inside the belt transmission, so the transmission inside the transmission case is There is a risk of lubricating oil leaking into the belt transmission chamber, and there are also problems in that it is difficult to maintain the belt transmission device and gear reduction mechanism, and the number of man-hours required to process the power unit casing increases, leading to high costs.

Furthermore, the transmission belt of the belt transmission device has a problem in that due to waving and vibration during operation, the transmission belt collides with the inner wall surface of the belt transmission case and generates a banging sound, which causes noise.

Therefore, the first invention eliminates lubricating oil leakage into the belt transmission chamber by preventing the mating surface of the transmission case from being located inside the belt transmission chamber, and improves maintainability of the heald transmission and gear reduction mechanism and processing of the transmission case. The first object of the present invention is to provide a motorcycle equipped with a swing type power unit that has good performance in all aspects.

A second object of the present invention is to reduce the generation of noise caused by waving and vibration of the power transmission belt.

B1 Structure of the Invention (Means for Solving Problem 11) To achieve the first object, according to the first invention, a power unit in which an engine and a transmission device having drive wheels mounted on a shaft is mounted on a vehicle body frame. In a motorcycle equipped with a swing-type power unit suspended vertically and swingably, the transmission case of the power unit is configured by combining a left side case and a right side case forming the main body thereof, The left side case is formed with a belt transmission chamber having an open surface on one side in the left-right direction, and a gear transmission chamber having an open surface on the other side in opposite directions. A belt transmission device that interlocks the crankshaft of the power unit and an output shaft mounted at the rear of the power unit is housed, a transmission case cover is attached to the open surface of the belt transmission chamber, and the gear transmission chamber includes: A gear reduction mechanism that interlocks the output shaft and the axle of the driving wheels is housed therein, and a transmission case cover is attached to the open surface of the gear transmission chamber.

In order to achieve the second object, according to the second invention, there is provided a swing vehicle in which a power unit in which an engine and a transmission device having drive wheels mounted on an axis is suspended on a vehicle body frame so as to be swingable up and down. In a motorcycle equipped with a power unit, a transmission case of the power unit is formed with a belt transmission chamber that accommodates a belt transmission that interlocks the engine and a drive wheel, and the belt transmission chamber is configured to accommodate a belt transmission that interlocks the engine and a driving wheel. The inner surface facing the outer peripheral surface of the power transmission belt is formed into a smooth continuous surface.

Said 1st. In the second invention, the swing type power unit may be of any type including a moped type,
Further, the engine and belt transmission device may have any structure without departing from the characteristics of the present invention.

(2) Effect According to the above configuration, the rotation of the crankshaft due to engine operation is transmitted to the rear wheels via the transmission device, and the gear ratio is automatically varied depending on the engine throttle operation and vehicle running conditions. controlled.

The left case, which constitutes the main body of the transmission case of the power unit, has a belt transmission chamber with an open surface on the left side on one side in the width direction, and a gear transmission chamber with an open surface on the right side on the other side. They are formed in opposite directions, and the open surface of the belt transmission chamber is covered by the transmission case cover, and the open surface of the gear transmission chamber is covered by the transmission case cover, so that there is a mating surface with the transmission case inside the belt transmission chamber. This prevents lubricating oil from leaking into the belt transmission chamber. Furthermore, the left and right open surfaces of the left case are located on both sides in opposite directions, making machining easy, and maintenance of the belt transmission or gear reducer can be performed simply by removing the mission cover or the mission case.

Furthermore, the inner surface of the belt transmission chamber facing the outer circumferential surface of the transmission belt is formed into a smooth continuous surface, so that the inner surface serves as a guide surface for the transmission belt, thereby suppressing its waving and vibration.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

In the following explanation, "front, rear", "left, right" and E
``Upper and lower'' refer to the forward direction of the motorcycle.

FIG. 1 is an overall side view of a movette type motorcycle equipped with the device of the present invention, FIG. 2 is a side view of a swing unit type power unit, and FIG. 3 is a plan view taken along the line III in FIG. In these figures, a front fork I, which suspends a front axle Wf, is steerably suspended from a head vibrator at the front end of a vehicle body frame F. A bracket 2 with a channel-shaped cross section is integrally hung on both sides of the central part of the vehicle body frame F in the longitudinal direction.A substantially horizontal support shaft 3 is fixed to the lower end of this bracket 2. The part is supported by a shaft 4 so as to be able to swing up and down. Further, a bracket B at the upper rear end of the power unit P is suspended on the rear part of the vehicle body frame F via a rear damper D''.

The power unit P is an air-cooled two-stroke engine E.
, a transmission T connected to the rear of the engine E, and a rear wheel Wr rotatably mounted on the rear of the transmission T.
The rear wheels Wr are driven by the engine E.

Fig. 4 is a partial side view of the power unit P as seen in Fig. 3 (Fig. Cross-sectional view of, No. 7
The figure is a longitudinal cross-sectional view taken along the line 1--2 in Figure 3, and the specific structure of the power unit (P) will be explained with reference to these figures and Figures 1 to 3.

The power unit P is composed of the engine E and the transmission T as described above, and the engine E is composed of the 2.4 and 6
, as shown in FIG. 7, has a cylinder portion 5 that extends substantially horizontally toward the front of the vehicle body frame F, and a crankcase portion 6 that is integrally connected to the cylinder portion 5, and as shown in FIG. The transmission case C of the device T includes a left side case C1 that is integral with the left half of the crankcase part 6 and extends long toward the rear to constitute the main part of the transmission case C, and a right half of the crankcase part 6. It is composed of an integral right side case Cr, and these are integrally coupled. The left open surface 9 of the left case C1, which constitutes the main body part, is covered with a transmission case cover CO consisting of a front cover 7 and a rear cover 8, and the right open surface of the right case Cr is covered with a transmission case cover Cm. .

The engine E is located at the foremost part of the power unit P, and is integrally connected to a cylinder part 5 that is tilted forward approximately horizontally so as to constitute an extension of the transmission device T, and is integrally connected to the left, Right case C! .

It has a crankcase part 6 formed of a part of Cr,
As shown in FIG. 6, a piston 12 is fitted into the cylinder bore 11 in the substantially horizontal cylinder portion 5 so as to be slidable back and forth, and a substantially horizontal rank shaft 13 is fitted into the crankcase portion 6 so as to be freely rotatable. The crank bin 13. of the crankshaft 13 is suspended horizontally on the crankshaft 13. and the piston pin 12 of the piston 12
．． A connecting rod 14 connects the two.

The intake boat 15 of the engine E is opened on the upper surface of the crankcase portion 10 of the engine E, and the intake boat 1
5 is connected to the intake system In. That is, this intake boat 15 has an intake pipe 16 with a carburetor Ca interposed therebetween.
The downstream ends of are connected. As shown in FIGS. 2 and 3, this intake pipe 16 extends rearward while curving to the right above the transmission case C, and its rear half curves downward toward the transmission case C, and its upstream end Air cleaner AC is connected to. As shown in FIGS. 2 and 3, the carburetor Ca is disposed above the engine E, in front of the shaft support 4 of the power unit P to the vehicle body frame F, and is open to the front, so that it is exposed to the wind when the vehicle is running. It is heated by the hot air from the engine E.

On the other hand, the air cleaner Ac is disposed behind the shaft support 4 in a dead space Sd on the right side of the transmission case C, and is away from the engine E, so that it is not easily exposed to hot air from the engine E.

As shown in FIGS. 2.3 and 6, the cylinder block 5. of the cylinder section 5 of the engine E. The outer periphery is covered with a box-shaped shroud 17 made of a heat-resistant synthetic resin material, and the cylinder radius 5. is shroud 17
It is exposed to the outside through a hole 18 opened on the top surface of the.

The left edge of the shroud 17 is fixed to the front edge of the left case C1 by bolts 20, and the right edge of the shroud 17 is fixed to the front edge of the shroud 17 along with the front of a hat-shaped fan cover 19 made of heat-resistant synthetic resin. The fan cover 19 is fixed to the old edge of the case Cr with bolts 21, and the rear part of the fan cover 19 is fixed to the right side case Cr with bolts 22.

A generator housing chamber 24 is formed by the fan cover 19, the shroud 17, and a part of the right case Cr, and within this housing chamber 24, an AC generator 25 attached to the right end of the crankshaft 13 and a cooling A fan 26 is housed.

As shown in FIGS. 3.4 and 6, a suction port communicating with the generator housing chamber 24 having a large number of rectifying plates 27 is opened in the rear half of the fan cover 19, and the rear side of the right case Cr has an outlet 2 communicating with the generator housing chamber 24.
9 is open.

When the cooling fan 26 is rotated, outside air flows into the accommodation chamber 24 through the suction port 28, cools the engine E and the alternator 25, and is then discharged to the outside through the discharge port 29.

As described above, the transmission case C of the power unit P includes a left case C1 that extends over substantially the entire length of the power unit P and constitutes the main part of the case C, and a right case C that is fixed to the front right side of the left case C1. Therefore, the left case CE is integrally molded from a metal material, synthetic resin, etc., and the left half of the crankcase portion 6 of the engine E is integrally formed on the front right side of the left case CE. The left outer surface of ! has an open surface 9 that is open to the outside over its entire surface, and a gas scale is attached to this open surface 9.
G (FIG. 8), the front cover 7 and the carrier cover 8 constituting the transmission case cover co are oil-tightly joined by a plurality of bolts 30 and 31, and a belt transmission chamber 33 is defined therein. will be accomplished. A V-belt type continuously variable transmission Mv, which will be described later, is housed within this transmission chamber 33. The right outer surface of the left case C1 has an open surface IO whose rear part is opened to the outside, and the mission case cover Cm is attached to the open surface 10 via a gasket G2 (FIG. 15) with a plurality of bolts 23. They are joined in an oil-tight manner, and a sealed gear transmission chamber 43 is defined therein. A gear reduction mechanism Gr, which will be described later, is housed within this gear transmission chamber 43.

The left case C1 and the mission case cover C
As is clear from FIG. 6, the joint surface with the gear transmission chamber 43 is located outside the belt transmission chamber 33, and even if the lubricating oil in the gear transmission chamber 43 leaks from the joint surface, the leaked oil will be transferred to the belt. It does not flow into the transmission chamber 33.

Front cover 7 constituting the transmission case cover Co
Both of the rear cover 8 and the rear cover 8 are integrally molded from a metal material or a synthetic resin material, and the rear edge of the front cover 7 and the front edge of the cover 8 are connected via a labyrinth packing 32 formed between them. External rainwater or the like is prevented from entering the belt transmission chamber 33 through the connecting portion.

Next, the structure of the connecting portion between the front cover 7 and the catch cover 8 will be explained with reference to FIGS. 2 and 6 and FIGS. 9 to 11. FIG. Figure 1O is a sectional view taken along line X-X in Figure 9, and Figure 11 is a cross-sectional view along line X-X in Figure 9.
These are partial cross-sectional views taken along the X-ray, and as is clear from these figures, the rear edge of the front cover 7 has an arc shape when viewed from the side and is formed in a channel shape with a cross section open to the outside. The front edge of the front cover 8 has an arc shape that is approximately the same shape as the rear edge of the front cover 7 when viewed from the side, and is formed in a channel shape with a cross section that is open inward.
When joined to the open surface 9 of the front cover 2, the rear edge of the front cover 7 and the front edge of the catcher cover 8 overlap each other to form a labyrinth patch 32 having a zigzag gap therebetween, as shown in FIG. do.

A belt type continuously variable transmission Mv is housed in a belt transmission chamber 33 defined in the transmission case C by the left case Cl and the gasket G.

This continuously variable transmission Mv connects the crankshaft 13 and an output shaft 34 that is rotatably supported on the rear part of the right side case Cr and the rear cover 8, and continuously changes the speed of 130 rotations of the crankshaft. can be transmitted to.

Since the belt-type continuously variable transmission Mv used is a conventionally known one, its structure will be briefly explained below.As shown in FIG. A variable diameter driven booby IJ37 is provided at the left end of the output shaft 34, and an endless belt 38 is suspended between the pulleys 36 and 37. The drive pulley 36 is a fixed drive pulley 36. fixed to the crankshaft 13. and a movable drive boot half 36. which is slidably supported in the axial direction on the crankshaft 13. This movable drive pulley half consists of 36! is subjected to centrifugal force, and the fixed drive pulley half rests 36. It is provided with a weight roller 39 for speed change that is moved in a direction closer to . In addition, the driven pulley 37
A fixed driven pulley half 371 is fixed to a hollow pulley shaft 40 rotatably supported on the output shaft 34, and a movable driven pulley half 371 is supported slidably in the axial direction on the hollow pulley shaft 40. The movable driven pulley half body 37□ is connected to the fixed driven pulley half body 37. by a spring 41. biased toward

An automatic starting centrifugal clutch 42 is provided on the output shaft 34 and outside the variable diameter driven pulley 37. This clutch 42 has a conventionally known structure, and when the rotation speed of the hollow pulley shaft 40 exceeds a set value, the pulley shaft 40
0 is coupled to the output shaft 34 via the clutch 42.

A gear chamber 43 is defined by the rear part of the left case C1 and the mission case Cm fixed to the right open surface 10 thereof. A reduction gear mechanism Gr is incorporated within this gear chamber 43. The opposing side walls of the gear chamber 43, that is, the left case CI! The output shaft 34 and the deceleration shaft 4 disposed parallel to the output shaft 34 are disposed between the transmission case Cm and the transmission case Cm.
4 and an axle 45 are each rotatably mounted horizontally via a pole bearing, and between the output shaft 34 and the axle 45, the output shaft 3
4. The rotation of the output shaft 34 is decelerated and transmitted to the axle 45 through a reduction gear mechanism Gr provided between the deceleration shaft 44 and the axle 45. The right end of the axle 45 protrudes outside the gear chamber 43, and the rear wheel W" is connected thereto. Therefore, when the crankshaft 13 is rotated by the operation of the engine E, the rotation is caused by belt continuously variable transmission. machine Mv, the output shaft 34 via the centrifugal clutch 42
The signal is transmitted to the rear wheel Wr via the reduction gear mechanism Gr.

As shown in FIG. 7, the left side case C that constitutes the belt transmission chamber 33! The inner surfaces of the upper and lower walls 60, 61 are curved in an arc shape with a large radius of curvature toward the belt transmission chamber 33 side, and are formed into smooth continuous surfaces with no unevenness. (2) A slipper surface of the belt 38 is formed facing the outer circumferential surface of the belt 38 on the tight side and slack side to suppress its waving and vibration. and (2) it becomes possible to omit a tensioner for tensioning the belt 38;

13 which is a sectional view of XI[[-XI[I in FIG.
As shown in the figure, left side case C! A plurality of voids 62... and 63... which open to the outer surfaces are formed in the upper and lower walls 60° and 61, respectively, and these voids 62...
and 63..., the open surface is the gasket G1
(1) It has a sound insulating effect that can reduce the hitting noise when the belt 38 collides with the inner surface of the upper and lower walls 60, 61 of the belt transmission chamber 33.

Furthermore, if a sound insulating rubber is further interposed between the voids 62, 63, . . . and the gasket 01, the sound insulating effect will be more effectively achieved.

The rear damper Dr (
A breather device Br for ventilating the belt transmission chamber 33, the gear transmission chamber 43, and the outside is integrally provided in the mounting bracket 8 (FIGS. 1 and 2).

Next, the structure of this breather device Br is shown in FIGS. 6 and 14.
This will be explained with reference to FIGS. Figure 14 is Figure 6)
'-XIV sectional view, Figure 15 is Figure 6 xv-x
The front view of Gaskera) Gz along the v line, Figure 16 is
As can be seen from these figures, FIG. 17 is a developed sectional view taken along the line x vi - The breather chamber 64 of the breather device Br is a first pleather chamber 64 formed in the mission case cover Cm.
1 and left case Cj! A second breather chamber 648 is formed at the rear of the first breather chamber 648. Second breather chamber 64
．． ．． 84□ is divided by gasket CZ (Fig. 15). The first breather chamber 641 on the side of the mission case cover Cm has a plurality of first breather chambers 641 as shown in FIGS.
．． 4th. The first chamber (a) has an inlet 65 that communicates with the gear transmission chamber 43, and the fourth chamber (a) is partitioned into a fifth chamber (a), (d), and (e). 5th house (b), (e
) are communicated through a communication port 66. On the other hand, the second breather chamber 64□ on the left case C2 side is
As shown in Figure 8, the second. 3rd and 6th chamber (b), (
C) and (f); Third room (b
), (C) are communicated through the communication port 67, and the sixth
The chamber has outlets 68, 69 communicating with the outside. As shown in FIG. 17, the first chamber (a) and the second chamber
chamber Φ), the third chamber (C), the fourth chamber (d) and the fifth chamber (e
) and the sixth chamber (f) are communicated with each other via lower through holes 0, 71 and 72 formed in the gasket G1, respectively. Therefore, the air containing oil mist in the gear transmission chamber 43 flows into the breather chamber 64 from the inlet 65 and flows in a zigzag pattern between the first chamber (a) and the sixth chamber (6) as shown by the arrow in FIG. During this time, the oil mist in the air is effectively separated and only the air is discharged to the outside through the outlets 68, 69. , which eliminates the need for a separate breather tube as in the past, resulting in a better appearance.

As shown in FIG. 12.14 and FIG. 16, at the bottom of the mating surface between the left case C1 and the transmission case cover 〇m, there are anchor halves 74° 74 that join together to form the anchor portion 74 of the brake wire 73. ! are integrally molded, and the inner 731 of the brake wire 73 is inserted into the insertion hole 75 formed by these anchor halves 74+ and 74□.
is inserted through the brake wire 73, and the outer 73° of the brake wire 73 is tied to the anchor portion 74. A brake arm 76 for operating a brake device provided on the rear wheel Wr is tied to the rear end of the inner 731 of the brake wire 73, and a brake release return spring 77 is provided between the anchor portion 74 and the brake arm 76.

Therefore, when molding the left case C2 and the missing case cover Cm, the anchor half 74. ．． 74□ can be integrally molded at the same time, so that the anchor portions 74
can be freely provided at a desired position on the transmission case C.

As shown in FIG. 4, below the crankcase portion 6 of the engine E, a starter motor 55 is fixed to the left case C2 constituting the main body of the transmission case C, and directly below the crankshaft 13, the left case Cj ! A starting chamber 80 in which a starting mechanism St for interlocking the starter motor 55 and the crankshaft 13 is housed is defined between the mating surfaces of the starter motor 55 and the front cover 7.

Next, the structure of the starting mechanism St and the starting chamber 80 is changed to the seventh
, and FIGS. 19 to 22, the 19th
The figures are a sectional view taken along line XIX-XIX in Figure 10,
The figure is a partial view of gasket CI along the line xx-xX in Figure 10, Figure 21 is a partial cross-sectional view of the gasket CI along the line xxr-xx in Figure 10, and Figure 22 is a partial cross-sectional view taken along the line xxn-xxn in Figure 19. As can be seen from these figures, in the starting chamber 80, the starter pinion 81 of the starter motor 55 is connected to the fixed drive boot half 361 of the variable diameter drive pulley 36 via the reduction gear 82,83. It meshes with a driven tooth ring 84 formed on the outer periphery of.

Therefore, when the starter motor 55 is driven, the starter pinion 81. Reduction gears 82, 83, and fixed drive boolean half 36. The crankshaft 13 is driven via the crankshaft 13.

A starting breather chamber 85 is formed in the starting chamber 80 . This starting breather chamber 85 includes the left side case C11 front cover 7 and the gasket G sandwiched between them.
1, and as shown in FIG.
A plurality of small chambers (6), (i), and a surface are defined by the 21st and 22nd sections on the outer periphery of the front cover 7.
As shown in the figure, a plurality of small chambers (c), (j), and ni) are defined by the partition wall 87 and the gasket G,
Said chambers (g), (h) and (j) are entrances 88.89
and 90 to the starting chamber 80, and a small chamber (
e) is communicated with the outside via the outlet 91. Also the 22nd
As shown in the figure, small room (g), (1) and small room (b), small room (i) and small room (e), and small room (goods) and small room (J)
are communicated with each other through ports 92, 93, 94 and 95 opened in the gasket G1, and furthermore, the small chambers (1) and (g) are communicated through a port 96 opened in the partition wall 86. The air in the starting chamber 80 communicating with the belt transmission chamber 33 flows in a zigzag pattern from the front and back in the small chamber of the breather chamber 85, as shown by the arrow in FIG. 22, and merges into the small chamber (E). Thereafter, it flows to the outside through the outlet 91 and the breathing action within the starting chamber 80 is performed. Furthermore, as described above, the breather chamber 85 has a zigzag passage formed by a plurality of small chambers, so that even if water may enter the breather chamber 85 from the outlet 9, it will not enter the starting chamber 80 or the belt transmission chamber 33. Never.

As clearly shown in Figures 2.4 and 5, the cell motor 55
At the lower front end of the transmission case C near the front of the
Hold the left and right pair of triangular step brackets 47.
are fixed to these brackets 47, and step rods 4
8 is suspended horizontally, and steps 49 are fixed to both left and right ends of this step rod 48, respectively. The step rod 48 and the left and right step brackets 47, 47 can also be used as protectors for the starter motor 55, and no separate protector is required.

Further, a stand bracket 50 is fixed to the front and rear intermediate portions of the left case C1 with poles 1-51, a main stand 52 is pivotally supported to the stand bracket 50, and a toggle spring 53 is installed between the main stand 52 and the stand bracket 50. The main stand 52 is stretched between the extended position and the retracted position by the toggling action of this spring 53! (Fig. 2).

A rear breather device 97 is provided at the rear lower end of the transmission case C to communicate the transmission chamber 33 from the rear to the outside.The structure of this rear breather device 97 is shown in FIGS.
This will be explained with reference to FIGS.

FIG. 23 is a partial sectional view of the left case C1 along the line xxm-xxm in FIG. 12, and FIG.
FIG. 25 is a partial cross-sectional view of the rear cover 8 taken along the line XXIV-XXV in FIG. 12, and FIG. 26 is a developed cross-sectional view taken along the line XXVI-XXVI in FIG. 23. As you can see from these figures, left case C! A rear breather chamber 98 is formed with the catcher cover 8 and the gasket G1 and projects further downward, and this breather chamber 98 is separated from the left side case C2 by a partition wall 99.
A small chamber 100 on the side and a small chamber 102 partitioned by both walls lO1 on the rear cover 8 side are partitioned by Gaskera FC+,
A port 103 communicating the compartments lOO and 102 is bored in the gas scaler) Gl.

The air in the belt transmission chamber 33 flows in a zigzag pattern through the small chambers 100 and 102 as shown in FIG. The belt transmission chamber 33 is discharged and a breathing action is performed between the belt transmission chamber 33 and the outside. Second
3.24 Outlet 10 of rear breather chamber 98 as shown in Figure 3.24
At the front of 6, a projecting piece 107 for generating negative pressure is provided to project backward and downward, and when the traveling wind hits this projecting piece 107, the vicinity of the outlet 106 tends to become negative pressure, which gives a suction effect to the breather chamber 98. The breathing effect is promoted.

In the figure, 54 is a known kick mechanism provided on the front cover 7, and 56 is a transmission mechanism (not shown) that connects the rear wheel W.
This is a pedal axis that is linked to r.

Next, the operation of the embodiment of the present invention will be explained.

When the engine E is operated now, the rotation of the crankshaft 13 is transmitted to the rear wheels Wr via the belt-type automatic continuously variable transmission Mv and the centrifugal clutch 42, and the rotation of the crankshaft 13 is transmitted to the rear wheels Wr via the belt-type automatic continuously variable transmission Mv and the centrifugal clutch 42. The gear ratio is automatically and variably controlled depending on the driving conditions of the vehicle.

The left case C that constitutes the main body of the transmission case C of the power unit P! A belt transmission chamber 33 having an open surface 9 on the left side on one side in the width direction, and a gear transmission chamber 43 having an open surface 10 on the right side on the other side are formed in opposite directions. Therefore, there is no mating surface of the mission case cover Cm inside the belt transmission chamber 33, and no lubricating oil leaks into the belt transmission chamber 33.

Furthermore, the left and right open surfaces 9,10 of the left case CP are located on opposite sides of each other, making machining easier, and furthermore, maintenance of the belt transmission 33 and gear reducer 43 easier.

Furthermore, when changing the centrifugal clutch 42 and the brake device, the transmission case cover Co and the transmission case cover Cm
All you have to do is change it.

In addition, the belt transmission chamber 33 has an inner surface facing the outer peripheral surface of the V belt 38 of the belt transmission device Mv formed as a smooth continuous surface, so that when the belt transmission device Mv is operated, the inner surface of the V belt 38 It acts as a guide surface and can suppress the undulations and vibrations of the belt 38.

C1 Effects of the Invention As described above, according to the first invention, since there is no mating surface of the transmission case in the belt transmission chamber in which the belt transmission device is housed, the lubricating oil in the transmission case is not absorbed into the belt transmission chamber. No leakage.

Further, since the left side case, which constitutes the main body of the transmission case forming the belt transmission chamber, has open surfaces on both left and right sides in the width direction, the open surfaces can be easily worked.

Furthermore, the maintainability of the belt transmission device and the gear reduction device can be improved.

Further, according to the second aspect of the present invention, it is possible to form a smooth guide surface for the transmission belt of the belt transmission device using the inner surface of the transmission case, and it is possible to suppress waving and vibration of the transmission belt.

[Brief explanation of drawings]

One drawing shows an embodiment of the present invention, in which Fig. 1 is an overall side view of a Movent type motorcycle equipped with a device of the present invention, Fig. 2 is a side view of a swing unit type power unit, and Fig. 3 is a side view of a Movent type motorcycle equipped with a device of the present invention. Figure 2 is a plan view as seen from the ■ line arrow, Figure 4 is a plan view as shown in Figure 3 ■
5 is a front view as seen from the V line in FIG. 2;
Fig. 6 is a cross-sectional view taken along the line Vl-IT in Fig. 2, Fig. 7 is a longitudinal sectional view of the transmission device taken along the line Fig. 3 - 9 is an enlarged view of the part shown by the arrow in FIG. 2, and FIG. 10 is a front view of the gasket along the
11 is a partial sectional view taken along the line X1-X1 in FIG. 9, FIG. 12 is a view taken along the line X■ in FIG. -
5 is a front view of the gasket taken along the line xv-xv in FIG. 6, and FIG. 16 is a front view of the gasket taken along the line xv-xv in FIG. 17 is a developed sectional view taken along line XX in FIG. 9, FIG. 18 is a perspective view of the pleaser device, and FIG. 19 is a sectional view taken along line XIX-XIX in FIG. 10. Figure 20 is a partial view of the gasket along line XX-XX in Figure 1O, Figure 21.
The figure is a partial sectional view along line XX I-XX I in Figure 10, and Figure 22 is a partial sectional view along line XX I-XX I in Figure 19.
The developed sectional view along the line, FIG. 23, is the same as FIG. 12 xxm-x.
24 is a partial sectional view of the gasket along line XXIV-XXPJwA in FIG. 12; FIG. 25 is a partial sectional view of the front cover along line xxv-xxv in FIG. 12; Figure 26 is Figure 23 XXVI
It is a developed cross-sectional view along the line -XXVI. C...Transmission case, E...Engine, F...Vehicle frame, P...Power unit, T...Transmission device, Cp...Left side case, Co...Transmission case cover, Cr. ...Right side case, Cm...Mission case cover, Gr...Gear reduction mechanism, Mv...V-belt type continuously variable transmission, St...Start 8! Side, Wr... Rear wheel as driving wheel, 9.10... Open surface, 13...
Crankshaft, 33...Belt transmission chamber, 34...Output shaft, 38...■ Belt as a transmission belt, 43...
・Gear transmission chamber, 45... axle

Claims (1)

[Scope of Claims] [1] A power unit (P) in which an engine (E) and a transmission device (T) having drive wheels (Wr) mounted on the shaft are integrated.
) is suspended on a body frame (F) so as to be able to swing up and down, and the transmission case (C) of the power unit (P) is the left side case that constitutes the main body of the motorcycle. (Cl) and the right case (
Cr), and the left case (Cl)
The belt transmission chamber (33) has an open surface (9) on one side in the left and right width direction, and has an open surface (10) on the other side.
A gear transmission chamber (43) having a belt transmission chamber (43) is formed in opposite directions, and a crankshaft (13) of the engine (E) and a power unit (P
) is accommodated in the belt transmission chamber (33).
A transmission case cover (Co) is attached to the open surface (9) of the gear transmission chamber (43), and the output shaft (
A gear reduction mechanism (Gr) that interlocks the axle (45) of the drive wheel (Wr) is accommodated in the gear transmission chamber (
Attach the mission case cover (C) to the open surface (10) of
A motorcycle equipped with a swing type power unit, characterized in that m) is attached thereto. [2] A power unit (P) in which an engine (E) and a transmission device (T) with drive wheels (Wr) mounted on the shaft are combined into a unit.
) is suspended on a body frame (F) so as to be able to swing up and down, and the transmission case (C) of the power unit (P) includes the engine (E); A belt transmission chamber (33) that accommodates a belt transmission (Mv) that interlocks the drive wheel (Wr) is formed, and the belt transmission chamber (33) accommodates a transmission belt (38) of the belt transmission (Mv). A motorcycle equipped with a swing type power unit, characterized in that an inner surface facing an outer peripheral surface is formed into a smooth continuous surface.