JPS6128913Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a belt drive pulley of 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 two. 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. The environment is conducive to an increase. 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, producing an air circulation effect.

However, in such a conventional cooling mechanism, most of the air discharged from the outer peripheral end 3a of the fin 3 first hits the inner surface of the side cover 4, and from there flows toward the movable face 5 as shown by arrow B in the figure. Because of the flowing structure, there was a problem in that not much cold air flowed into the friction area of the pulley with the belt, which needed the most cooling, resulting in poor cooling efficiency.

The present invention has been made in consideration of the above circumstances, and is provided with a recess that extends from the outer surface of the pulley to the friction surface of the pulley with the belt on the outer peripheral edge of the pulley, which has fins with a fan function on the outer surface. A belt-type power transmission mechanism in which grooves are formed at intervals in the circumferential direction of the pulley, allowing more cooling air to be sent to the friction area between the pulley and the belt to efficiently cool both. The purpose is to provide a belt driven pulley.

Hereinafter, the present invention will be explained with reference to 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 is fixed to the movable face 17, and a weight roller 24 is interposed between the ramp plate 23 and the movable face 17. The distance between the opposing surfaces of the ramp plate 23 and the movable face 17 is formed to gradually become narrower toward the outer circumference, so that 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 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 circumferential 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, side fins 18b
The outer circumferential edge of the fixed face 18 extends close to the outer circumferential edge of the fixed face 18, and grooves 18d are formed in the outer circumferential edge of the fixed face 18 between the respective fins 18a. A part of the air discharged from the periphery is fixed face 18
It is designed so that it can be easily discharged to the inner surface side (drive belt 16 side).

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 the interior of the cold air inlet 11a. 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, so that the cold air is introduced between the guide plate 11c and the inner surface of the bulging portion 11a. A cold air introduction path 11d leading from the port 11b to a cold air inlet 18c common to each of the air blowing paths a.
is formed. Further, the seam between the side cover 11 and the engine case 10 is substantially an extension of the outer peripheral edge of the movable face 17, and a seal 26 is provided at this seam. As shown in the figure, the gasket 26 is formed into a plate shape that extends into the transmission compartment so as to function as a so-called partition plate that partitions the transmission compartment into the side cover side and the engine case side. Note that reference numeral 27 indicates an outside air introduction pipe connected to the cold air introduction port 11b, and 28
is an outlet for 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, since grooves 18d are formed in the portions between the fins 18a on the outer peripheral edge of the fixed face 18 of the drive pulley 14, each air passage a is Low-temperature air discharged from the outer peripheral end of each fin 18a through the inside of each groove 1
It is also discharged from the portion 8d and flows directly into the friction portion of the drive pulley 14 with the belt 16. Therefore, drive pulley 14 and belt 16 are efficiently cooled. Here, the low-temperature air discharged as it is from the outer peripheral end of each fin 18a first collides with the inner surface of the side cover 11 and is deflected, and is further deflected by the surface of the packing 26, so that it is connected to the belt 16 of the drive pulley 14. drive pulley 14 and belt 16 are further cooled.

In addition, in order to provide the above-mentioned cooling effect, the depth and size of the groove 18d, as well as
Needless to say, the gap between the inner surface of the side cover 11 and the concave groove 18d, which the discharged air hits, the relative position of the gasket 26 to the drive pulley 14, etc. are set to optimal specifications.

Although the illustrated embodiment shows an example in which the present invention is applied to a drive pulley in a belt-type automatic transmission of a motorcycle, it is of course applicable to a driven pulley of the same transmission.

As explained above, the present invention has a drive belt wound between a drive pulley provided on the output shaft side and a driven pulley provided on the output shaft side, and an outer surface of at least one of the two pulleys. In a belt-type power transmission mechanism in which a plurality of fins having a fan function are formed in the belt, a groove is formed on the outer peripheral edge of the pulley having the fins, the groove leading from the outer surface of the pulley to the friction surface side with the belt. Since the pulleys are formed at intervals in the circumferential direction, a greater amount of cooling air can be directly sent to the friction portion of the pulley and the belt, thereby providing an excellent effect in that both can be efficiently cooled.

[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, 17... Movable face, 18... Fixed face, 18a... Fin, 18d... Concave groove, a... Air duct.

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 a large number of fins having a fan function are formed on the outer surface of at least one of the two pulleys. In the belt type power transmission mechanism,
A belt-type power transmission mechanism, characterized in that concave grooves are formed on the outer peripheral edge of the pulley having the fins, extending from the outer surface of the pulley to the friction surface side with the belt, at intervals in the circumferential direction of the pulley. belt driven pulley.