JPS627893Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a belt drive pulley for a belt-type power transmission mechanism.

For example, in motorcycles with relatively low engine output among motorcycles, belt-type automatic transmissions that mainly use V-belts and variable diameter pulleys are often used as a means of transmitting the rotation of the engine's output shaft to the drive wheels. has been done.

As is well known, in this type of automatic transmission, power is transmitted to the drive wheels through the frictional resistance between the belt and the pulley, so the belt heats up due to the frictional heat generated between the belt and the pulley. In order to prevent dust, muddy water, etc. from entering the transmission, the entire transmission is covered with a cover, so in addition to the frictional heat mentioned above, the temperature is also affected by heat conduction and radiant heat from the engine. We are in an environment where it is easy for a rise to occur. Therefore, in the past, in order to prevent temperature increases due to these factors, especially heating of the belt, for example, as shown in FIG. A large number of fins 3 are integrally provided on the side surface to constitute a cooling fan, and the fan forcibly circulates the air within the transmission chamber. In the figure, 5 is a movable face, 6 is a drive belt, and 7 is an engine case.

By the way, as for the air circulation effect by this fan, the rotation of the fan, that is, the rotation of the fixed face 2, causes a flow of air in the direction of arrow A along the surface of the fin 3, which is discharged from the outer peripheral end 3a of the fin 3. As a result, the space on the inner circumferential end 3b side of the fin 3 becomes a negative pressure, and air from the vicinity of the side cover 4 is continuously taken in from this part, resulting in an air circulation effect.

However, in such a conventional cooling mechanism, since a gap α is formed between the outer edge of the fin 3 and the inner wall surface of the side cover 4, a part of the air flowing in the direction of arrow A is absorbed into the gap. The air also flows into the part α, and as a result, no effective negative pressure is generated in the above-mentioned space, resulting in a weak point in which the air blowing efficiency is reduced accordingly. In order to effectively generate this negative pressure and increase air blowing efficiency, the gap α should be made as small as possible or eliminated. However, in reality, the cover 4 is a removable fixed body, and one of the fins 3 is a rotating body, so it is necessary to ensure a gap α so that they do not interfere with each other.

The present invention was developed taking the above points into consideration, and includes forming air passages on the outside of the fins that have a fan function, between each fin and between the outside surface of the pulley. The side fins are formed integrally with the pulley, thereby generating effective negative pressure and increasing the air blowing efficiency. Also, by forming the side fins integrally in this way, there is no need to assemble the fins, which increases the number of parts. An object of the present invention is to provide a belt drive pulley for a belt-type power transmission mechanism that is free of turbulence.

Hereinafter, the present invention will be explained based on an embodiment shown in the attached FIGS. 2 to 4.

The illustrated embodiment is an application of the present invention to a belt type automatic transmission, and in these figures,
10 is an engine case, 11 is a side cover that covers a side opening of the engine case 10, and 12 is a crankshaft of the engine 13. On the side cover 11 side of the crankshaft 12, a drive pulley 14 with a centrifugal variable diameter structure is installed.
Further, driven pulleys 15 with a variable diameter structure are provided on driven shafts (none of which are shown) that transmit rotation to the rear wheels, and these pulleys 14, 1
A drive belt 16 having a V-belt structure mainly made of rubber is wound between the belts 5 and 5.

The drive pulley 14 has a movable face 1 made of aluminum having good thermal conductivity, for example.
7 and a fixed face 18, the movable face 17 is fitted onto the outer periphery of a boss collar 19 fitted onto the crankshaft 12 so as to be slidable in the axial direction, and the fixed face 18 is arranged on the inner and outer surfaces thereof. It is fitted onto the shaft end of the crankshaft 12 while being held by thrust washers 20 and 21, and is press-fixed to the end of the boss collar 19 by a nut 22 that is screwed onto the shaft end. . A ramp plate 23 facing the movable face 17 is fixed to the end of the boss collar 19 opposite to the side to which the fixed face 18 is pressed. A weight roller 24 is interposed between them. The gap between the facing surfaces of the ramp plate 23 and the movable face 17 is formed to become gradually narrower toward the outer circumference, and when the weight roller 24 moves outward under the influence of centrifugal force, the centrifugal force The movable face 17 moves in the direction of the fixed face 18 to a position that balances the force. Therefore, the effective radius around which the belt 16 is wound around the drive pulley 14 becomes larger. The sliding range of the movable face 17 is restricted by a tapered collar 25 fitted into the outer periphery of the base of the crankshaft 12.

4a and 4b show the fixed face 18 of the drive pulley 14, which is the gist of the present invention. As you can understand from these figures,
A large number of straight fins 18a constituting an air blowing fan are formed on the outer surface of the fixed face 18 at equal intervals in the circumferential direction.
Side fins 18b forming air passages a between the outer surfaces of the fins 8 and 8 are integrally formed with the fins 18a. The outer surface of this side fin 18b is
As shown in FIG. 4a, it is formed flush with the outer edge of the fin 18a, and when viewed from the side as shown in FIG. A circular cold air inlet 18c is formed in the center. In addition, the side fins 18b
The outer peripheral edge of the fixed face 18 extends close to the outer peripheral edge of the fixed face 18, and grooves 18d are formed between the respective fins 18a on the outer peripheral edge of the fixed face 18, and the outer peripheral edges of the fins 18a pass through the air passage a. A part of the air discharged from the fixed face 18 is easily discharged toward the inner side of the fixed face 18 (toward the drive belt 16 side). In addition, each fin 18
A has a fixed face 18 and a side fin 18.
An extending portion 18e protrudes in the radial direction from the outer peripheral portion of b.
are installed in succession.

Further, as shown in FIGS. 2 and 3, the side cover 11 is formed with a bulging portion 11a that bulges outward at a portion corresponding to the fixed face 18, and this bulging portion A cold air inlet 11b is formed for introducing low temperature outside air into 11a,
Further, the inside of the bulging portion 11a is a recess 11e into which the drive pulley 14 is inserted, and the extending portion 18e of the fin 18a is brought close to the inner peripheral surface of the recess 11e. And furthermore,
The guide plate 11c extends from the front part of the side cover 11 so as to be close to the outer surface of the side fin 18b of the fixed face 18, and thereby the guide plate 11c and the bulge 1
1a, there is a cold air inlet 18c common to each of the air passages a from the cold air inlet 11b.
A cold air introduction path 11d leading to is formed. Incidentally, reference numeral 26 denotes a gasket which is interposed at the joint between the engine case 10 and the side cover 11 and which also functions as a so-called partition plate that forms the flow of air along the drive belt 16 located inside the side cover 11. 27 is an outside air introduction pipe connected to the cold air introduction port 11b, and 28 is an outlet for the air introduced into the transmission compartment.

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

When the drive pulley 14 rotates due to the rotation of the crankshaft 12, a large number of fins 18a having a fan function formed on the outer surface of the fixed face 18 generate air flow in the direction shown by the arrow in FIG. do. That is, low-temperature air taken in from the outside flows into the cold air inlet 18c, which becomes a negative pressure due to the rotation of the fins 18a.
The low-temperature air flows from 1b through the cold air introduction path 11d, and is acceleratedly discharged from the outer peripheral end side of each fin 18a through the air blowing path a between each fin 18a. This discharged low-temperature air exchanges heat with the drive belt 16, drive pulley 14, etc., which are in a high temperature state due to mutual frictional heat, and cools them while sequentially flowing toward the rear driven pulley 15. flowing away,
Heat exchange is performed in the same manner as the driven pulley 15, and the heat is discharged to the outside from the discharge port 28.

By the way, in the present invention, each fin 1 of the fixed face 18 in the drive pulley 14
A state in which side fins 18b forming the air passage a between the respective fins and the outer surface of the fixed face 18 on the outer side of the fins 8a are close to the side cover 11 inside the recess 11e. Therefore, due to the action of the side fins 18b, the low-temperature air passing through each air passage a can pass through, for example, the guide plate 11c along the way.
All the liquid is discharged from the outer peripheral end side of each fin 18a without being discharged to the side. As a result, an effective negative pressure is generated near the cold air inlet 18c, which increases the blowing efficiency of the fan and increases the amount of cold air introduced. Furthermore, the air in the circumferential portion of the recess 11e is forcibly discharged to the outside of the recess 11e by the extending portion 18e formed on the fin 18a, and from this point as well, the air is efficiently directed toward the drive belt 16. The cooling effect is enhanced.

On the other hand, the side fins 18b having such an effect
Since they are formed integrally with each fin 18a of the fixed face 18, there is no need to assemble the fins at all, and each fin 18a in this embodiment has a strait shape as shown in the figure. Therefore, it is easy to demold after molding, and therefore has good workability. Furthermore, since the side fins are integrally molded in this way, the number of parts does not increase.

Although the illustrated embodiment shows an example in which the present invention is applied to a drive pulley in a belt-type automatic transmission for a motorcycle, it goes without saying that the present invention can also be applied to a driven pulley in the same transmission.

As explained above, in the present invention, a drive belt is wound between a drive pulley provided on the output shaft side and a driven pulley provided on the output shaft side, and at least one of the pulleys for,
In a belt-type power transmission mechanism in which a large number of fins having a fan function are formed on the outer surface of the belt-type power transmission mechanism and the outer surface is covered with a cover, a pulley on which the fins are formed is inserted into the cover. A concave portion is formed on the outer side of the fin, and an air passage is formed between the respective fins and between the outer surface of the pulley, and a side fin is disposed in close proximity to the cover. are integrally provided, and the fins are formed with extensions that protrude in the radial direction from the outer peripheries of the pulley and the side fins. This prevents inhaled air from being discharged into the gap between the cover and the recess. The air near the inner peripheral surface of the belt is forcibly discharged to the drive belt side, and as a result, effective negative pressure is generated, increasing air blowing efficiency.Furthermore, there is no need to assemble fins, which increases the number of parts. It has excellent effects such as no problems.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted sectional view showing a conventional example, and Figs. 2 to 4 show an embodiment of the present invention.
The figure is a sectional view of the main part, Figure 3 is a partially cutaway schematic side view, Figure 4a is a partially cutaway side view of the fixed face,
FIG. 4b is a longitudinal sectional view of the fixed face. 12... Crankshaft, 14... Drive pulley, 15... Driven pulley, 16... Drive belt, 18... Fixed face, 18a...
Fin, 18b... Side fin, a... Airflow path.

Claims (1)

[Scope of utility model registration request] A drive belt is wound between a drive pulley provided on the output shaft side and a driven pulley provided on the output shaft side, and at least one of the two pulleys has a large number of fans having a fan function on its outer surface. In the belt type power transmission mechanism, the outer surface of the belt-type power transmission mechanism is formed with a fin, and the outer surface is covered with a cover, and the cover is formed with a recess into which a pulley having the fin is inserted, and the fin is A side fin is integrally provided on the outer side, forming a ventilation path between the respective fins and between the outer surface of the pulley and disposed in close proximity to the cover, and the fin has A belt drive pulley for a belt-type power transmission mechanism, characterized in that an extension part is formed that projects in the radial direction from the outer periphery of the pulley and side fins.