JPH0143360Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a cooling device for a belt type automatic transmission in a unit swing type power unit installed in a small vehicle such as a scooter type motorcycle or a three-wheeled motor vehicle. .

Prior Art In the power unit equipped with a belt-type automatic transmission, heat is generated not only by engine combustion heat but also by frictional contact between the belt-type automatic transmission and the pulley. In order to eliminate this generated heat from inside the transmission case, for example, as shown in FIG. By rotation of a cooling fan 07 provided integrally with a drive pulley attached to a shaft 05, outside air is introduced into the transmission case 03 through an intake port 04, and hot air is discharged through an exhaust port 08 at the rear.

Problems to be Solved by the Invention In such a structure, it is difficult to dispel the hot air accumulated between the drive pulley 06 and the engine side wall 09 (space part), and the movable half 06A of the drive pulley 06
The temperature of the side members tends to rise.

Means and Effects for Solving the Problems An object of the present invention is to efficiently exhaust heat within a belt-type automatic transmission formed integrally with an engine, thereby promoting cooling of the drive pulley.

The purpose of the present invention is to provide a belt type automatic transmission for a unit swing type power unit.
A cooling fan is installed on the crankshaft between the drive pulley attached to one end of the crankshaft that protrudes toward the transmission side and the engine part, and the cooling fan is installed at the part where the engine crankcase and transmission case are connected. This is achieved by providing an intake port in the transmission case at a location corresponding to the cooling fan.

According to the above configuration, when the cooling fan rotates together with the crankshaft and the drive pulley, outside air enters the high-temperature part inside the transmission case through the intake port, and the hot air is released from the exhaust port provided in other parts to eliminate the accumulation of hot air. is discharged through.

Embodiment Hereinafter, an embodiment of the present invention shown in FIGS. 2 and 3 will be described.

FIG. 2 shows a main part sectional view of a swing unit type power unit 10 for a motorcycle. is formed as a single piece. A rear axle RA is supported at the rear of the transmission case 20, and the power of the engine 12 is transferred to the automatic transmission 2.
4. The signal is transmitted to the rear axle RA via the reducer 64.

An automatic transmission 24 housed in an inner chamber A defined by transmission cases 20 and 22 includes a drive pulley 26 mounted on a crankshaft 16 extending into the inner chamber A.
, a driven pulley 54 on a driven shaft 52 disposed at the rear of the transmission cases 20 and 22, and both pulleys 2
The main body includes a V-belt 70 that is wound between 6 and 54. The drive pulley 26 includes a fixed half body 28 which is fixed to the shaft end of the crankshaft 16 and integrally includes a cooling fan 30 made up of a plurality of blades.
Crankshaft 1 can be freely displaced in the axial direction and cannot be rotated relative to each other.
6, and a movable half body 32 fitted on the lamp plate 3, adjacent to the movable half body 32.
4 is fixed to the crankshaft 16, and a plurality of spherical weights 36 are interposed between the ramp plate 34 and the movable half 32.

Further, between the lamp plate 34 and the engine 12, a seal plate 38 fitted onto the crankshaft 16 is screwed tightly covering the engine side surface of the movable half body 32. A cooling fan 40 consisting of a plurality of blades is mounted on the side surface.
is fixed. An air guide port 44 corresponding to the cooling fan 40 is provided adjacent to the cooling fan 40.
A partition wall 42 having a
is fixed to.

Furthermore, a vertically elongated intake port 46 is located on the front wall of the transmission case 20 and is located closer to the engine than the bulkhead 42.
is formed, and the air intake port 46 is provided with an air guide tube 4 having a dust removal filter 50 attached to the air intake port.
8 is fitted.

In addition, in FIG. 2, the head 13 of the engine 12 is shown tilted forward in an exploded view, so it looks as if the wind guide tube 48 and the head 13 are adjacent to each other, but they are actually The two are in a positional relationship as shown in FIG. 3 (however, FIG. 3 is a schematic sectional view taken along the line - in FIG. 2).

On the other hand, the driven pulley 54 on the driven shaft 52 disposed at the rear of the transmission cases 20 and 22 consists of a fixed half body 56 and a movable half body urged toward the fixed half body 56 by a compression coil spring 60. A V is formed between the driving pulley 26 and the driven pulley 54.
A belt 70 is wound around the driven pulley 5.
4, an automatic centrifugal clutch 62 is connected to the driven shaft 5.
It is mounted on 2.

This embodiment is configured as described above, and while the engine 12 is in operation and the crankshaft 16 is rotating at a low speed, the weight 36 is positioned inward (closer to the crankshaft 16). However, since the movable half 32 of the drive pulley 26 is closer to the engine side, the winding diameter of the V-belt 70 is small, but as the rotational speed of the crankshaft 16 increases, the centrifugal force corresponding to the speed 36 is deviated outward (in the centrifugal direction), the movable half 32 is pushed by the weight 36 and moved toward the fixed half 28 (see the two-dot chain line), and the V-belt 7
The winding diameter of 0 becomes larger. In the driven pulley 54, if the winding radius on the driving pulley 26 is small, the movable half 58 is closer to the fixed half 56 (large winding radius), and if the winding radius on the driving pulley 26 is large, the movable half 58 is closer to the fixed half 56 (large winding radius). The body 58 is shortened against the elastic force of the compression coil spring 60 and is located at a position separated from the fixed half body 56 (large winding radius). Also, while the engine is rotating at a speed lower than the constant speed, the automatic centrifugal clutch 62 is activated.
The automatic centrifugal clutch 62 is in the OFF state, but when the constant speed is exceeded, the automatic centrifugal clutch 62 becomes the ON state and the driven shaft 5
2 rotates, and the rear axle RA rotates via the reduction gear 64.

On the other hand, since the cooling fan 40 rotates as the crankshaft 16 rotates, outside air is drawn into the air guide tube 48 through the filter 50 as shown by arrow B, and this draws air into the air intake port 46 and the air introduction port 44. After passing through, it flows in the radial direction of the cooling fan 40, flows along the outer circumference of the drive pulley 26, and then flows into the drive pulley 2.
6 and the V-belt 70, flowing backward in the inner chamber A while removing heat generated by the frictional contact between the V-belt 70 and the V-belt 70. This air enters the compartment C formed at the rear of the transmission case 22 while absorbing the frictional heat generated by the driven pulley 54, and then is discharged to the outside through the exhaust port 80. The exhaust port 80 has a double wall structure to prevent foreign matter from entering from the outside.

In this way, the transmission case 20 is the crank case 1.
An intake port 46 and a cooling fan 40 are provided in the high-temperature part connected to the engine 4, and a structure is adopted in which outside air is taken into the interior chamber A through the intake port 46. Hot air is not trapped, and therefore the temperature rise of the movable half 32 side member of the drive pulley 26 is effectively suppressed. Moreover, a partition wall 42 having an air guide port 44 is disposed close to the cooling fan 40 on the engine side, and the air that has passed through the air guide port 44 is transferred to the partition wall 42.
2 and the seal plate 38, the entire drive pulley 26 is evenly cooled, which is extremely effective. This effect is furthered by the cooling fan 30 integrated with the fixed half body 28, and the heat accumulation portion in the interior chamber A is completely eliminated. As a result of the above, the durability of the V-belt 70 is significantly improved, and it is possible to reduce vehicle maintenance costs.

Effects of the Invention As is clear from the above explanation, in the present invention, in a unit swing type power unit, between the drive pulley attached to one end of the crankshaft protruding toward the transmission side and the engine part. A cooling fan is placed on the crankshaft, and an intake port is provided in the transmission case at the location where the engine crankcase and transmission case connect, and corresponds to the cooling fan. The hot air from the high-temperature part connected to the crankcase is wiped away, suppressing the temperature rise of the member located on the engine side of the drive pulley, and uniformly cooling the drive pulley as a whole.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a motorcycle power unit equipped with a cooling device for a belt-type automatic transmission according to the known art, and FIG. 2 is a cross-sectional view of a motorcycle power unit equipped with a belt-type automatic transmission cooling device according to the present invention. A cross-sectional view of the unit, FIG. 3 is a schematic cross-sectional view of the main part taken along the - line. 10...power unit, 12...engine,
13...Head, 14...Crankcase, 16...
...Crankshaft, 18...Transmission, 20...Transmission case, 22...Transmission case, 24...Automatic transmission, 26...Drive pulley, 28...Fixed half body,
30...Cooling fan, 32...Movable half body, 34...
... Lamp plate, 36 ... Weight, 38 ... Seal plate, 40 ... Cooling fan, 42 ... Bulkhead, 4
4...Air guide port, 46...Intake port, 48...Air guide tube, 50...Filter, 52...Driver shaft, 54
... Driven pulley, 56 ... Fixed half body, 58 ... Movable half body, 60 ... Compression coil spring, 62 ...
...Automatic centrifugal clutch, 64...Reduction gear, 70...
V-belt, 80...exhaust port.

Claims (1)

[Claims for Utility Model Registration] The crankshaft is formed integrally with the engine disposed toward the width direction of the vehicle body, and the crankshaft is formed integrally with a drive pulley attached to one end of the crankshaft, and the drive pulley is wound around the drive pulley. In a belt type automatic transmission comprising a driven pulley to which power is transmitted by a belt and supporting a driving wheel shaft at the rear, a cooling fan is disposed on the crankshaft between the driving pulley and the engine part. Cooling of a belt-type automatic transmission, characterized in that an intake port is provided in the transmission case at a portion where the engine crankcase and the transmission case are connected and correspond to the cooling fan. Device.