JP3519133B2 - Motorcycle drive unit cooling structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit cooling structure for discharging cooling air from a drive unit of a motorcycle.

[0002]

2. Description of the Related Art Conventionally, some motorcycles have the following structure.

That is, a drive unit is pivotally supported on a body frame so as to be vertically swingable, and a rear wheel is supported on a swing end of the drive unit. The drive unit includes an engine and a power transmission device that transmits the power of the engine to the rear wheels. The power transmission device includes a V-belt winding mechanism and a transmission case that covers the V-belt winding mechanism. Is equipped with.

Further, the center of the tire width of the rear wheel is located on the center line of the vehicle body in the vehicle width direction, and the transmission case is deviated to one side from the center line. On the other hand, while the cooling air is introduced into the same transmission case as above, a discharge hole for discharging the cooling air from the same transmission case is formed in the rear portion of the same transmission case.

[0005]

By the way, in the above-mentioned conventional structure, there is a possibility that foreign matter such as dust or muddy water that has been splashed up while the motorcycle is traveling may enter the transmission case through the discharge hole.

Therefore, in order to prevent the entry of the foreign matter, it is conceivable to devise the shape of the discharge portion such as the discharge hole for discharging the cooling air from the inside of the transmission case. However, since the transmission case is usually made by casting, there is a limit to the shape of the discharge part due to die cutting, etc., that is, the degree of freedom in selecting the shape to prevent the entry of foreign matter. There is a problem that is narrow.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and when a motorcycle is running, an exhaust portion for exhausting cooling air from the transmission case of the drive unit is provided. It is an object of the present invention to prevent foreign matter from passing through the discharge portion and easily entering the transmission case.

It is another object of the present invention to improve the degree of freedom in selecting the shape when the shape of the discharge portion is desired.

[0009]

In order to achieve the above object, a motorcycle drive unit cooling structure according to the present invention has a structure in which the center of the tire width of the rear wheel is located on the center line in the vehicle width direction of the vehicle body of the motorcycle. Then, the transmission case is deviated to one side from the center line, and cooling air is introduced into the same transmission case as above, while an exhaust hole for discharging the cooling air from the same transmission case is provided at the rear of the same transmission case. In the formed motorcycle drive unit cooling structure, the discharge hole is formed in the bottom plate that constitutes the bottom of the transmission case so as to vertically penetrate the bottom plate, and the resin duct is fitted into the discharge hole. , An inlet opening for introducing cooling air from the inside of the transmission case is formed in the upper part of this duct, and an outlet opening for discharging cooling air from the inside is formed in the lower part of the same duct. The rearward is obtained by opening.

[0010] Also, when is fitted to the duct to the discharge hole, the abutting flange portion on the lower surface of the bottom plate of the transmission case is integrally formed in the duct, Rise at least a portion of the flange portion on the outer side The inner space of the bulging portion is provided as at least a part of the cooling air passage.

Further , the lower portion of the duct is constructed to discharge and open.
Of the left and right side walls located to the left and right of the mouth,
Extend the rear edge of one side wall behind the rear edge of the other side wall
It is as an extension.

In the above case, the lower portion of the duct is projected below the bottom plate of the transmission case, and the lower surface of the lower portion of the duct is an inclined surface that extends upward in the vehicle width direction as it moves away from the center line of the vehicle body. .

Further, the cooling air passage in the duct may be rearwardly downward.

[0014]

[Operation] The operation of the above configuration is as follows.

The rear wheel 1 is placed on the center line 36 of the vehicle body 2 in the vehicle width direction.
2 is located on the same side as above, a discharge hole 53 is formed in the transmission case 23 of the power transmission device 10 which is deviated to one side of the center line 36, and a duct 54 is fitted into the discharge hole 53 to insert the transmission case 23. The cooling air 37 inside is discharged through the duct 54.

Therefore, since the rear wheel 12 and the duct 54 are deviated from each other in the vehicle width direction, the foreign matter flipped up by the rear wheel 12 while the motorcycle 1 is running jumps into the duct 54. Things are suppressed.

Further, the discharge opening 58 of the duct 54 is opened rearward.

Therefore, in general, the foreign matter flipped up by the rear wheel 12 is directed rearward, so that the foreign matter is prevented from jumping into the discharge opening 58.

Moreover, the duct 54 is made of resin and can be easily formed into various shapes.

Therefore, the cooling air 37 is fed from the inside of the transmission case 23.
The shape of the discharge portion 46 for discharging the can be easily formed into a desired shape by resin molding the duct 54.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 1 is a scooter type and swing unit type motorcycle, and is indicated by an arrow Fr in the figure.
Indicates the front of it. The right and left described below means the vehicle width direction and the direction toward the front.

A front fork 3 is rotatably supported on the front portion of the vehicle body 2 of the motorcycle 1, a front wheel 4 is supported on the lower end of the front fork 3, and a handle 5 is mounted on the upper end. On the other hand, a drive unit 7 is pivotally supported on a rear portion of the vehicle body 2 so as to be vertically swingable by a pivot shaft 8, and a rear wheel 12 is supported on a swing end of the drive unit 7 via an axle 11. .

The drive unit 7 comprises a two-cycle or four-cycle engine 9 and a power transmission device 10 for transmitting the power of the engine 9 to the rear wheel 12 side.
The engine 9 and the power transmission device 10 are connected to each other.

The swinging end of the rear portion of the drive unit 7 is supported by the shock absorber 14 on the rear portion of the vehicle body 2, and
Seat 15 is mounted on the rear of the vehicle.

When the power of the engine 9 is transmitted to the rear wheels 12 via the power transmission device 10, the motorcycle 1
Becomes capable of traveling on the road surface 16, and the rider sitting on the seat 15 steers the steering wheel 5 to operate the motorcycle 1.
Is driven. In addition, the impact from the road surface 16 while running,
It is absorbed by the front fork 3 and the shock absorber 14.

2 and 3, the engine 9 comprises a crankcase 18 and a cylinder 19 projecting forward from the crankcase 18, and the crankcase 18 has a crankshaft 20 whose axial center extends left and right. Is supported.

The power transmission device 10 includes a V-belt winding mechanism 22 and a transmission case 23 made of aluminum casting that covers the V-belt winding mechanism 22. This transmission case 23
Has a case main body 24 integrally connected to the crankcase 18, and the case main body 24 is open to the left, which is one lateral side. A case cover 25 is provided which closes the opening of the case body 24 in an openable and closable manner. The case cover 25 is detachably fastened to the case body 24 by a fastener 26.

The V-belt winding mechanism 22 is accommodated in the front portion of the transmission case 23 and is supported by one end of the crankshaft 20. The drive pulley 28 and the transmission case 2 are the same as above.
3, a driven pulley 29 accommodated in the rear part of the drive pulley 23 and supported by the transmission case 23, and a V belt 30 wound around the drive pulley 28 and the driven pulley 29.
The driven pulley 29 is connected to the gear reduction means and the rear wheel 12 via the axle 11.

The power of the engine 9 is the crankshaft 2
0, V belt winding mechanism 22, the gear reduction mechanism, and the axle 11 to the rear wheel 12. On this occasion,
The V-belt winding mechanism 22 is configured such that the speed reduction ratio automatically decreases as the rotation of the crankshaft 20 increases.

The motorcycle 1 has a kick starter 32 as a starting device. The kick starter 32 includes a kick shaft 33 supported by the case cover 25 of the transmission case 23, a kick pedal 34 supported by the kick shaft 33, and an engagement / disengagement with the crank shaft 20 in association with the kick shaft 33. It is composed of a freely engaging means 35. When the kick pedal 34 is depressed at the time of starting, the engaging means 35 interlocked with this is engaged with the crankshaft 20 to perform cranking.

The center of each tire width of the front wheels 4 and the rear wheels 12 is located on the center line 36 of the vehicle body 2 in the vehicle width direction, and the transmission case 23 is one side from the center line 36 on the left side. Have been biased to.

A cooling device 38 for cooling the power transmission device 10 with a cooling wind 37 which is a running wind is provided.

The cooling device 38 has a guide path 39 for guiding the cooling air 37 introduced from the front part of the vehicle body 2 to the front part of the transmission case 23. The transmission case 23
A communication hole 41 for communicating the internal space 40 of the transmission case 23 with the outside of the transmission case 23 is formed in the front part of the case cover 25. An element 42 that closes the communication hole 41 is provided, and a cover 43 that detachably covers the element 42 from the outside is provided. A flexible pipe 44 is provided downstream of the guide path 39.
The downstream end of the flexible pipe 44 is connected to the cover 43.

The cooling air 37 guided by the guide passage 39 is filtered through the element 42 and then introduced into the front part of the internal space 40 of the transmission case 23.

Cooling air 3 introduced into the transmission case 23
A discharge portion 46 for discharging 7 is provided at the rear portion of the transmission case 23. The cooling air 37 in the transmission case 23 flows along the V-belt 30 from the front part to the rear part of the internal space 40 of the transmission case 23 to cool the V-belt winding mechanism 22 and the like as a whole. After that, it is discharged from the discharge portion 46 to the outside of the transmission case 23.

The discharge portion 46 will be described in all the drawings.

The case cover 25 of the transmission case 23 is composed of a ceiling plate 47 and a bottom plate 48 which are vertically separated from each other and face each other, and a side plate 49 which integrally connects the respective outer edges thereof. .

A tubular body 51 is integrally projected upward from the upper surface of the bottom plate 48, and the tubular body 51 has a rectangular cross section in plan view. One side wall of the cylindrical body 51 is formed by the side plate 49. The inside of the cylindrical body 51 is a discharge hole 53 which communicates the internal space 40 of the transmission case 23 with the lower side of the transmission case 23. The discharge hole 53 is
The bottom plate 48 is penetrated in the up-down direction, and has a rearwardly downward shape.

A resin duct 54 is removably fitted into the discharge hole 53 from below. This duct 5
4 has a rectangular cross section, and the outer surface of the duct 54 is in surface contact with the inner surface of the discharge hole 53.

Inside the duct 54 is a cooling air passage 56, an upper portion of the cooling air passage 56 is an introduction opening 57 for introducing the cooling air 37 from the transmission case 23, and a lower portion of the cooling air passage 56 is the same as above. From this cooling air passage 56, the cooling air 3
It is a discharge opening 58 for discharging 7 to the outside of the transmission case 23.

A locking means 60 is provided which locks the duct 54 fitted in the discharge hole 53 to the transmission case 23 in a disengageable manner and attaches it to the transmission case 23. The locking means 60 has three hooks 61 that integrally project from the upper portion of the duct 54 upward along the inner surface of the discharge hole 53.

Each of these hooks 61 is elastically engaged with and disengaged from the upper end edge of the cylindrical body 51 which is the opening edge of the upper opening of the discharge hole 53, whereby the duct 54 causes the transmission case 23 to move. Is attached to.

The lower portion of the duct 54 has the bottom plate 48.
It projects down to below. The duct 5 in the discharge hole 53
A collar portion 62 that abuts the lower surface of the bottom plate 48 when the 4 is fitted is integrally formed in the lower portion of the duct 54.

A part of the collar portion 62 bulges outward,
The internal space of the bulging portion 63 constitutes a part of the cooling air passage 56.

An elastic cushion material 65 made of rubber or the like is interposed between the lower surface of the bottom plate 48 and the collar portion 62 while being elastically compressed. Due to the elastic force of the cushion material 65, the hooks 61 are elastically pressed against the upper edge of the tubular body 51, so that the duct 54 is securely attached to the transmission case 23 without rattling. Has been. Further, the cushion material 65 has a sealing function, and the cushion material 65 prevents rainwater from flowing into the transmission case 23 through between the inner surface of the discharge hole 53 and the outer surface of the duct 54. It

In the free state, the free end side of each hook 61 is expanded slightly outward from the cross-sectional shape of the discharge hole 53.

When the duct 54 is fitted into the discharge hole 53 and is attached to the transmission case 23, first, the cushion material 65 is attached on the flange portion 62, and then the duct member 65 is attached.
The hooks 61 are slightly moved closer to each other against their own elasticity. In this state, from below the discharge hole 53,
The hooks 61 and the duct 54 are sequentially fitted into the discharge hole 53.

With the above-mentioned fitting, the cushion material 65 becomes the bottom plate 4.
When it comes into contact with the lower surface of 8, the cushion material 65 is slightly elastically compressed and further fitted. Then, the hooks 61 are elastically and automatically locked to the upper edge of the tubular body 51, whereby the attachment of the duct 54 to the transmission case 23 is completed.

In the above case, while the rear wheel 12 is located on the center line 36 of the vehicle body 2 in the vehicle width direction, the center line 36 is the same as above.
Since the transmission case 23 of the power transmission device 10 is deviated to one side and the duct 54 is provided in the transmission case 23, the rear wheel 12 and the duct 54 are deviated from each other in the vehicle width direction. Therefore, while the motorcycle 1 is traveling, the rear wheels 12
The foreign matter bounced up by is prevented from jumping into the duct 54, so that the foreign matter is prevented from entering the transmission case 23 through the duct 54.

The discharge opening 58 of the duct 54 is open rearward.

For this reason, in general, the foreign matter bounced up by the rear wheel 12 faces rearward, so that the foreign matter is prevented from jumping into the discharge opening 58.

The lower surface of the lower portion of the duct 54 is an inclined surface 66 which is directed upward as it is separated from the center line 36 of the vehicle body 2 in the vehicle width direction.

Therefore, even if the motorcycle 1 is largely banked due to cornering or the like, the lower portion of the duct 54 is prevented from coming into contact with the road surface 16.

Of the left side wall 68 and the right side wall 69 which constitute the lower part of the duct 54 and are located on the left and right of the discharge opening 58, the rear end of the right side wall 69 on the side of the center line 36 of the vehicle body 2 is the other side. The left side wall 68, which is a side wall, extends rearward from the rear end of the left side wall 68 and serves as an extending portion 69a.

Therefore, the extending portion 69a can more reliably prevent the foreign matter bounced up by the rear wheel 12 from jumping into the discharge opening 58.

As described above, since the cooling air passage 56 in the duct 54 has a rearward descending shape, in general, the foreign matter bounced up by the rear wheel 12 is directed rearward. A discharge opening 58 below the cooling air passage 56
Is prevented from jumping into. In addition, the cooling air passage 5
6 is vertically long, and therefore foreign matter is more reliably prevented from entering the transmission case 23 through the duct 54.

[0058]

The present invention has the following effects.

According to the first aspect of the present invention, the rear wheel is positioned on the centerline of the vehicle body in the vehicle width direction, while the discharge hole is formed in the transmission case of the power transmission device which is offset to one side of the centerline. Then, a duct is fitted in the discharge hole so that the cooling air in the transmission case is discharged through the duct.

Therefore, the rear wheel and the duct are deviated from each other in the vehicle width direction, so that the foreign matter bounced up by the rear wheel while the motorcycle is traveling is prevented from jumping into the duct. .

Therefore, foreign matter is prevented from entering the transmission case through the duct.

Further, the discharge opening of the duct is opened rearward.

Therefore, in general, the foreign matter flipped up by the rear wheel is directed rearward, so that the foreign matter is prevented from jumping into the discharge opening. Therefore, foreign matter can be more reliably prevented from entering the transmission case through the duct.

Moreover, the duct is made of resin and can be easily formed into various shapes.

Therefore, the shape of the discharge portion for discharging the cooling air from the inside of the transmission case can be easily made into a desired shape by resin molding of the duct, so that the degree of freedom in selecting this shape is improved.

[0066] Further, when is fitted to the duct to the discharge hole, the abutting flange portion on the lower surface of the bottom plate of the transmission case are integrally molded into the duct.

Therefore, when the duct is attached to the transmission case, when the duct is fitted into the discharge hole together with the hook and the collar portion is brought into contact with the lower surface of the bottom plate, the hook is locked as described above. The Rukoto.

Therefore, the free movement of the duct up and down in the discharge hole is prevented by the hook locking and the abutment with the flange portion. Therefore, the duct is attached to the transmission case. Will be ensured.

[0069] Further, by bulging at least a portion of the flange portion on the outer side, there the inner space of the expanded portion as at least a part of the cooling air passage.

Therefore, the collar portion is effectively used for forming the cooling air passage. Therefore, with a simple configuration, the cross-sectional area of the cooling air passage is increased, the cooling air is smoothly discharged from the transmission case, and the cooling effect is improved .

Further , the lower part of the duct is constructed to discharge and open.
Of the left and right side walls located to the left and right of the mouth,
Extend the rear edge of one side wall behind the rear edge of the other side wall
It is as an extension.

Therefore, the foreign matter bounced up by the rear wheel is
If you try to jump into the discharge opening,
And more reliably prevented. Therefore, through the duct
The entry of foreign matter into the transmission case 23 is more reliably prevented.
It

According to the second aspect of the present invention, the lower portion of the duct is made to project below the bottom plate of the transmission case, and the lower surface of the lower portion of the duct is raised in the vehicle width direction with increasing distance from the center line of the vehicle body. It is an inclined surface facing away.

Therefore, even if the motorcycle makes a large bank due to cornering or the like, there is an advantage that the lower portion of the duct is prevented from coming into contact with the road surface, that is, the bank angle can be made large.

According to the third aspect of the invention, the cooling air passage in the duct is formed in a rearward descending shape.

For this reason, generally, the foreign matter bounced up by the rear wheel is directed rearward, so that the foreign matter is prevented from jumping into the discharge opening at the lower portion of the cooling air passage. Therefore, foreign matter can be more reliably prevented from entering the transmission case through the duct.

[Brief description of drawings]

1 is a cutaway view of FIG. 4. FIG.

FIG. 2 is an overall side view of the motorcycle.

FIG. 3 is a plan sectional view of a power unit.

FIG. 4 is a partially enlarged view of FIG.

5 is a sectional view taken along line 5-5 of FIG.

6 is a view taken along line 6-6 of FIG.

FIG. 7 is a perspective view of a duct.

[Explanation of symbols]

1 motorcycle 2 car body 7 Drive unit 9 engine 10 Power transmission device 12 rear wheels 22 V belt winding mechanism 23 Transmission Case 36 Center line 37 Cooling wind 40 interior space 46 Discharge part 48 bottom plate 51 cylinder 53 Discharge hole 54 duct 56 Cooling air passage 57 Introductory opening 58 Discharge opening 60 Locking means 61 hook 62 collar part 63 bulge 65 cushion material 66 inclined surface 68 Left side wall 69 right side wall 69a extension part

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62J 39/00

Claims (3)

(57) [Claims] 1. A drive unit is swingably pivoted up and down on a body frame, and a rear wheel is supported on a swing end of the drive unit. A power transmission device for transmitting to the wheel side, the power transmission device including a V-belt winding mechanism and a transmission case covering the V-belt winding mechanism, and the rear wheel on the center line in the vehicle width direction of the vehicle body. The center of the tire width is located, the transmission case is deviated to one side from the center line, and cooling air is introduced into the transmission case as above, while the cooling air is discharged from the transmission case as above. In the drive unit cooling structure for a motorcycle having the same structure as the above in the rear part of the transmission case, the discharge hole is formed in the bottom plate constituting the bottom part of the transmission case so as to vertically penetrate the bottom plate, and the discharge hole is formed. A resin duct is fitted in the hole, and an inlet opening for introducing cooling air from the inside of the transmission case is formed in the upper portion of the duct, while an outlet opening for discharging cooling air from the inside is formed in the lower portion of the same duct. the discharge opening is opened toward the rear, when is fitted to the duct to the discharge hole, and integrally molding the flange section in contact with the duct on the lower surface of the bottom plate of the transmission case,
By bulging at least a portion of the flange portion on the outer side, the inner space of the expanded portion and at least a portion of the cooling air passage, located to the left and right discharge opening constitutes the bottom of the duct
Of the left and right side walls, remove the rear end of the side wall on the centerline side of the vehicle body.
A drive unit cooling structure for a motorcycle, which has an extending portion extending rearward from a rear end of one side wall . 2. The lower part of the duct is made to project below the bottom plate of the transmission case, and the lower surface of the lower part of the duct is an inclined surface that faces upward in the vehicle width direction, away from the center line of the vehicle body. The drive unit cooling structure for a motorcycle according to 1 . 3. A drive unit cooling structure for a motorcycle according to claim 1 or 2 , wherein the cooling air passage in the duct has a rearward descending shape.