JPH0526328A - Swing case cooling structure for unit swing type engine - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is a unit swing that can be implemented at a low cost, can improve the aesthetic appearance of the swing case, and can provide a reliable cooling effect and a waterproof effect in the swing case. It is to provide a swing case cooling structure for a type engine. A swing case cooling structure for a unit swing type engine according to the present invention is provided with an exhaust port 26 formed in the swing case 5 so that the inside of the swing case 5 and the rear brake chamber 32 communicate with each other. ..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing case cooling structure for a unit swing type engine which allows the outside air to flow in the swing case to prevent the belt from being deteriorated by frictional heat.

[0002]

2. Description of the Related Art In a unit swing type engine, a V-belt continuously variable transmission, a deceleration transmission mechanism, etc. are housed inside a swing case connected to a crankcase of the engine part and extending rearward. Since it supports the rear wheels, it is compact, has good maintainability, and is inexpensive, and is therefore widely used in small motorcycles such as scooter type vehicles.

The above-mentioned V-belt continuously variable transmission changes the effective diameters of the drive V-pulley and the driven V-pulley around which the V-belt is stretched by centrifugal force to continuously change the gear ratio.

In this speed change method, in order to prevent power loss due to slippage between the V belt and each V pulley,
The tension of the belt is increased and the V pulleys are pressed strongly. Therefore, the frictional heat during operation is high, and the V-belt is deteriorated by the heat as it is. Therefore, in many unit swing type engines, the wind guide port and the exhaust port are opened in the swing case and provided on the side surface of the drive V pulley. The fan forcedly introduces outside air into the swing case to air-cool the V-belt continuously variable transmission.

An air cleaner or the like is installed at the air guide port, and the air taken into the swing case is dustproof and waterproof.

[0006]

However, many of the air outlets are provided as simple holes below the swing case, and there is a risk that water will enter the inside of the swing case when the vehicle is running on a submerged road. However, the opening area of the exhaust port could not be made large, and the cooling effect was not sufficiently obtained.

In order to solve the above problem, there are some which have a waterproof structure at the air outlet, but since the shape of the air outlet becomes complicated and large, the swing case becomes expensive and has an aesthetic appearance. Was forced to get worse.

The present invention has been made in consideration of the above problems and can be implemented at a low cost to improve the aesthetic appearance of the swing case and to provide a reliable cooling effect and waterproof effect in the swing case. To provide a swing case cooling structure for a simple unit swing type engine.

[0009]

To achieve the above object, in a swing case cooling structure for a unit swing type engine according to the present invention, an air guide port and an exhaust port are formed in a swing case connected to an engine portion to open the outside air. In the swing case cooling structure of the unit swing type engine for circulating the V-belt continuously variable transmission and the like housed inside the swing case in the swing case cooling structure.
It is provided so that the inside of the swing case communicates with the rear brake chamber.

[0010]

When the swing case cooling structure of the unit swing type engine is constructed in this way, water does not enter the inside of the rear brake drum even when running on a submerged road. The wind vent is surely waterproof.

Further, since the opening area of the exhaust port can be made large, a sufficient cooling effect can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a cross section of a unit swing type engine to which the present invention is applied.

The unit swing type engine 1 has a general layout that is often used in scooter type vehicles and the like, and the engine portion 2 forming the first half thereof is, for example, a two-stroke engine having a horizontal single cylinder cylinder 3. A swing case 5 is connected to the crankcase 4 of the engine portion 2 and extends rearward.

The swing case 5 is a case in which a case body 6 which is integral with the crank case 4 and a case cover 7 which is fitted to the case body 6 from the outside are fixed by fixing bolts 8. The V-belt continuously variable transmission 11 and the starting clutch 1 are provided on the crankshaft 9 and the drive shaft 10 which project into the case 5.
2, and the deceleration mission mechanism 13 is mounted on the shaft.

The V-belt continuously variable transmission 11 has a drive V-pulley 14 which is integrally rotatable with the crankshaft 9 and a driven V-pulley 1 which is rotatable on the drive shaft 10.
5 and a V-belt 16 that is stretched between these V-pulleys 14 and 15. The drive V-pulley 14 and the driven V-pulley 15 automatically change the effective diameter of the drive V-pulley 14 as the centrifugal force changes, and continuously change the gear ratio.

The starting clutch 12 is, for example, a centrifugal connection type that is integrally rotated with the driven V pulley 15.
The driven V pulley 15 is gradually rotated integrally with the drive shaft 10 as the rotation speed increases.

Further, as shown in FIG. 4, the deceleration mission mechanism 13 includes, for example, three deceleration gears 17, 18, 19.
The case body 6 is held in the mission chamber 21 in which the rear part of the case body 6 is liquid-tightly covered by the mission cover 20 and the lubricating oil O is sealed, and the rotation of the drive shaft 10 is 2
The speed is reduced to a stage and transmitted to the rear axle shaft 23 that supports the rear wheel 22.

In the unit swing type engine 1 thus constructed, the reciprocating motion of the piston 24 sliding back and forth in the cylinder 3 is converted into the rotary motion of the crankshaft 9 via the connecting rod 25. Then, the rotation of the crankshaft 9 is transmitted to the drive shaft 10 via the V-belt continuously variable transmission 11 and the starting clutch 12 described above, and after being decelerated by the deceleration mission mechanism 13, the rear axle shaft 23 is rotated to rotate the rear wheel 22. To drive.

By the way, in order to prevent the heat deterioration of the V-belt 16 by cooling a large amount of frictional heat generated during the operation of the V-belt continuously variable transmission 11, the swing case 5 is provided with a cooling member as shown in FIG. Air guide port 25 for introducing outside air and an exhaust port 26 for discharging the air inside the swing case 5 to the outside.
Is provided.

The air guide port 25 is formed in the case cover 7 so as to be located right next to the fan 27 that is integrally rotated with the drive V pulley 14, for example.
An air hose 28 and an air cleaner 29 are sequentially connected to. An exhaust port 26, which will be described later, is provided above the rear part of the case body 6.

When the fan 27 rotates together with the drive V-pulley 14, a negative pressure is applied to the air guide port 25, and the outside air is sucked into the air cleaner 29. After the outside air is dusted by a cleaner element 30 such as a sponge, it enters the inside of the swing case 5 through an air hose 28 and flows rearward to cool the V-belt continuously variable transmission 11, and then the exhaust port 2
It is discharged from the swing case 5 after passing through 6.

4 and 5 show the case body 6 respectively.
The left side surface and the right side surface of a rear part are shown. 1 is a cross-sectional view taken along the line I-I of FIGS. 4 and 5, and FIG.
FIG. 5 shows an embodiment of the present invention.

In a general unit swing type engine, as shown in FIGS. 1 and 5, a rear brake chamber 32 is located adjacent to the right side of the mission chamber 21.
In the rear brake chamber 32, a rear brake drum 33, which is integrally rotated with the rear wheel 22, is formed between the rear brake chamber 32 and the case body 6, and a brake shoe 34 attached to the case body 6 side is housed therein. ing.

During braking of the scooter type vehicle 1, the brake shoe 34 is expanded in the rear brake drum 33 and pressed against the inner peripheral surface of the rear brake drum 33, and the friction generated at this time causes the rear brake drum 33 to rotate. Is braked.

Now, the exhaust port 26 is, for example, from the outside of the outer peripheral wall 35 of the mission chamber 21 from the rear brake chamber 3
Swing case 5
The interior is communicated with the rear brake chamber 32.

Since the air exhaust port 26 is formed at two locations with a reinforcing rib 37 for reinforcing and supporting the bearing 36 of the rear axle shaft 23 interposed therebetween, the formation of the air exhaust port 26 impairs the strength of the case body 6. There is no fear of being caught.

In this way, the air A that has cooled the V-belt continuously variable transmission 11 inside the swing case 5 passes through the air exhaust port 26 to the rear brake chamber 32, as shown in FIG.
It is discharged from the space between the drum flange 38 formed on the case body 6 and the rear brake drum 33 to the outside.

In the rear brake chamber 32, it is difficult for the outside water to enter due to the drum flange 38, so that
The air exhaust port 26 that opens to the upper part of the rear brake chamber 32 is reliably waterproofed. Therefore, the opening area of the exhaust port 26 can be increased, and a sufficient cooling effect can be provided inside the swing case 5.

Further, the exhaust port 26 can be easily formed by casting when the case main body 6 is manufactured by casting, and no additional processing or the like is required, so that the cost is not increased at all.

Further, since the air outlet 26 is not exposed to the outside of the swing case 5, the aesthetic appearance of the swing case 5 is improved.

[0032]

As described above, the swing case cooling structure of the unit swing type engine according to the present invention is
A swing case of a unit swing type engine in which a wind guide port and an exhaust port are formed in a swing case connected to an engine part to allow outside air to flow inside the swing case and cool a V-belt continuously variable transmission and the like housed therein. In the cooling structure, since the air outlet is provided so as to communicate the inside of the swing case with the rear brake chamber, the air outlet is reliably waterproof inside the rear brake chamber, and there is no risk of water entering the inside of the swing case.

Therefore, the opening area of the exhaust port can be made large, and a sufficient cooling effect is provided inside the swing case.

Further, since the exhaust port can be formed by casting, it can be formed without increasing the cost, and since the exhaust port is not exposed outside the swing case, the aesthetic appearance of the swing case is improved. ..

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention and is a cross-sectional view taken along line I-I of FIGS. 4 and 5.

FIG. 2 is a cross-sectional view of a unit swing engine to which the present invention is applied.

FIG. 3 is a left side view of the unit swing engine shown in FIG.

FIG. 4 is a left side view of the rear part of the case body.

FIG. 5 is a right side view of the rear part of the case body.

[Explanation of symbols]

 1 unit swing type engine 2 engine part 4 crankcase 5 swing case 11 V-belt continuously variable transmission 12 starting clutch 13 deceleration mission mechanism 22 rear wheel 23 rear axle shaft 25 air guide 26 exhaust pipe 32 rear brake chamber 33 rear brake drum

Claims (1)

Claim: What is claimed is: 1. A V-belt continuously variable transmission in which an air guide port and an exhaust port are formed in a swing case connected to an engine portion to allow outside air to flow inside the swing case and to be housed inside. A swing case cooling structure for a unit swing type engine for cooling a unit swing type engine, wherein the exhaust port is provided so as to communicate the inside of the swing case with a rear brake chamber.