JPS59164226A - Cooler for internal-combustion engine - Google Patents

Abstract

PURPOSE:To lengthen service life of V-belt by cooling the interior of transmission case containing V-belt automatic stepless transmission forcefully with wind sucked from outside. CONSTITUTION:A case cover 23 is secured air-tightly through a gasket G to the open side of case body in a transmission case 2 provided on a cylinder block. While a V-belt stepless transmission T where a V-belt 12 is stretched over a drive pulley on the crank shaft and an inverted pulley 11 on the output shaft 9 is contained in a case 23. Furthermore a wind guide wall for forming a scroll cooling wind path P where the interted pulley side 11 is communicating with wind lead port 45 while the driving pulley side is communicating with discharge port is provided on the inner wall of cover case. A suction fan 50 for sucking cooling wind through said port 45 into said path P is provided integrally on the back of inverted pulley 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for an internal combustion engine, particularly suitable for use in an internal combustion engine mounted on a motorcycle.

In internal combustion engines for motorcycles, etc., the crankshaft of the engine and the output shaft are arranged side by side in a transmission case connected to the cylinder block, and they are connected via a V-belt type automatic continuously variable transmission. There are known systems in which the gear ratio can be automatically changed depending on engine throttle operation and vehicle driving conditions.

However, the continuously variable transmission is generally housed in a sealed transmission case, and the drive, driven pulley, and V
Since it has heat-generating parts such as contact parts with the belt, the temperature inside the transmission case tends to rise, and this tendency is especially large in compact transmission cases, and V-belts have the problem of being prevented from deteriorating due to heat generation. .

In view of the above-mentioned circumstances, the present invention provides a cooling device capable of effectively forcibly cooling the inside of a transmission case of an engine using cooling air sucked in from the outside, thereby extending the life of each member of a continuously variable transmission, especially the V-belt, which is easily heated. The purpose is to provide
To achieve this purpose, the transmission case connected to the cylinder block has a case cover fixed to the open side of the main body of the case via a gasket, and a continuously variable transmission is housed within the case cover. The air guide wall provided on the case cover and the gasket form a scroll-shaped cooling air passage in which the driven pulley side is connected to the air guide port and the drive goo +7 side is connected to the air exhaust port, and the back side of the driven pulley is connected to the air guide wall provided on the case cover and the gasket. A suction fan is provided for sucking cooling air into the cooling air passage from the air guide port.

EMBODIMENT OF THE INVENTION Hereinafter, an embodiment in which the present invention is applied to a two-stroke internal combustion engine for a motorcycle will be described with reference to the drawings.

In the following description, "front, rear" and "left" are used.

"Right" refers to the body frame F of the motorcycle.

In FIGS. 1 and 12, a two-stroke internal combustion engine is mounted on a body frame F of a motorcycle. The engine main body E of this engine includes a cylinder block 1 that is tilted forward with respect to the vehicle body frame F, and a transmission case 2 that is integrally connected to the lower part of this block 1. A crank chamber 3 is formed at the front, and a mission chamber 4 is formed at the rear.

The transmission case 2 is constructed by integrally joining cover cases 2□ and 23 on the left and right sides of a case main body 2I divided into left and right halves. A crankshaft 5 is rotatably supported in the crank chamber 3 of the transmission case 2, and a crank pin 5. A piston 8 that slides into the cylinder γ via a connecting rod 6 is connected to the cylinder γ. In the transmission chamber 4 of the transmission case 2, an output shaft 9 is rotatably supported in parallel with the crankshaft 5.

A V-belt type automatic continuously variable transmission T suspended between the crankshaft 5 and the output shaft 9 is disposed inside one side of the transmission case 2. Since this transmission T is conventionally known,
To briefly explain its structure, a drive boot is provided at the right end of the crankshaft 5, and a driven pulley 11 having a larger diameter than the drive pulley 10 is provided at the right end of the output shaft 9. An endless V-belt 12 is suspended between the boots IJ 10 and 11. The drive pulley 10 includes a fixed drive pulley half-hole fixed to the crankshaft 5, and a movable drive pulley half-hole 102 located on the outside of the fixed drive pulley half-hole 101, which is slidably supported on the crankshaft 5 in the axial direction. The movable drive pulley half-rest 10□ is subjected to centrifugal force and is connected to the fixed drive plate body 10. A weight roller 13 for speed change is provided to move the weight roller 13 in a direction closer to . The driven pulley 11 is fixed to a hollow pulley shaft 14 that is rotatably supported on the output shaft 9, and is connected to a fixed driven pulley half 111 located behind the movable drive pulley half 102 of the drive pulley 10. , the pulley shaft 1
a movable driven pulley half 1 which is slidably supported in the axial direction of 4 and is located inside a fixed driven pulley half 11;
1□, this movable driven pulley half 11
□ is a driven pulley half 11 fixed by a pulley spring 15
, is biased toward .

An automatic starting centrifugal clutch C is provided on the output shaft 9 and inside the driven pulley 11. Since this centrifugal clutch C is also conventionally known, its structure will be briefly explained as follows.
A drive plate 17 supporting a clutch weight 16 is fixed to the end of the pulley shaft 14, and a clutch outer 19 is fixed to the clutch shaft 18 which is spline-engaged with the output shaft 9. 140 When the rotational speed exceeds a set value, the clutch weight 16 engages the clutch outer 19 and the pulley shaft 14 is coupled to the output shaft 9.

A reduction gear case 20 is formed at the center of the rear part of the transmission case 2 so as to surround the left half of the output shaft 9, and a reduction gear mechanism R is incorporated into this reduction gear case 20. Inside the reduction gear case 20, there is a reduction shaft 2 parallel to the output shaft 9.
1 is rotatably supported, and this reduction shaft 21 is integrally provided with a large diameter first reduction gear 22 and a small diameter second reduction gear 23. The first reduction gear 22 is meshed with a drive gear 24 that is integrated with the output shaft 9, and the second reduction gear 23 and the output shaft 9 are meshed with each other.
The final shaft 26 is rotatably fitted into the right end of the final shaft 26, and is meshed with a large-diameter third reduction gear 25 that is integrated with the final shaft 26. The final shaft 26 is rotatably supported by the reduction gear case 2°, and its left half protrudes outside the reduction gear case 20. A driving sprocket 28 of the chain reduction mechanism 27 is fixed thereto, and this sprocket 28 is connected to the endless chain reduction gear 29. It is linked to a rear wheel (not shown) via. Therefore, when the crankshaft 5 is rotated by engine operation, this rotation is transmitted to the output shaft 9 via the V-belt type automatic continuously variable transmission T and the centrifugal clutch C.
The signal is then transmitted to the rear wheels via the reduction gear mechanism R, the final shaft 26 and the cheno reduction mechanism 27.

To the left of the final shaft 26, a pedal drive shaft 3o rotatably supported by the cover case 22 is arranged in tandem on the same axis as the final shaft 26. It is linked to a pedal crank (not shown) via. A clutch ring 32 is slidably fitted to the outer peripheries of the final shaft 26, the pedal, and the drive shaft 30 to connect them together or to break the connection. 33 are connected. When the clutch ring 32 is in the engaged position as shown in FIG. 2, the pedal drive shaft 30 and the final shaft 26 are connected, and the final shaft 26 can be driven by the driver's pedal depression, so that the pedal travel is not possible. It becomes possible. Further, when the operating handle 33 is shifted to the left as shown by the chain line in FIG. 1, the clutch ring 32 is also shifted to the left and the connection between the final shaft 26 and the pedal drive shaft 30 is severed.

An alternator A is connected to the left end of the crankshaft 5. Additionally, a pinion shaft 34 is provided between the crankshaft 5 and the output shaft 9.
A pinion 35 at the left end of this pinion shaft 34 is provided.
An internal gear 36 is engaged with the starting kick shaft.
Further, the starting gear 37 that is engaged with the right end of the crankshaft 5
It can be engaged with and disengaged from the upper driven gear 38.

In FIG. 1, 4c and (J'a) are the air cleaner and carburetor of the intake system of the engine body E.

Incidentally, a novel cooling device is provided in the transmission case 2 to effectively cool the continuously variable transmission T incorporated therein.

Next, the specific configuration of this cooling device will be explained.

The cover case 23 is fixed to the open side surface of the case main body 2I with a plurality of mounting bolts 49 via a gasket G, and the continuously variable transmission T is housed within the cover case 23. As clearly shown in FIG. 9, the cover case 23, the air guide wall 43 (to be described later) provided on the inner surface of the cover case 23, and the gasket C cooperate to form a scroll shape around the outer periphery of the continuously variable transmission T. A cooling air passage P is formed. That is, the cover case 23 and the gasket G form the outer peripheral wall and left and right walls of the cooling air passage P, and the air guide wall 43 provided on the inner surface of the cover case 23 partitions the drive pulley 10 and the driven pulley 11. As shown in FIG.
The lower end of α is connected to the bottom surface of the outer peripheral wall of the cover case 23, and the free end ends before reaching the upper surface of the outer peripheral wall of the cover case 23. The arc-shaped wall 43a and the straight wall 4:1 face each other to the drive pulley 10 from the driven booby side of the scroll-shaped cooling air passage P.
A communication passage 47 to the side is formed.

On the other hand, the gasket (G) extends inward from the upper side of the cover case 23 between the drive pulley 10 and the driven pulley 11, as shown in FIGS.
The extension portion Ga is the straight wall 43b as shown in FIG.
It is joined to the end face of the arcuate wall 43a, and also to the free end of the arcuate wall 43a via the spacer 48. As described above, the cover case 23, the air guide wall 43, and the gasket G form the scroll-shaped cooling air passage P around the outer periphery of the continuously variable transmission T. As shown in FIGS. 2, 4 and 7, a cover plate 40 is fixed to the outside of the cover case 23 facing the driven pulley 11 with a plurality of setscrews 5γ, and the cover plate 40 and the cover case 23 are used for cooling. Wind inflow passage 4
1 is formed.

This inflow passage 41 is directed toward the upper part of the transmission case 2.
connected to c'. Also, the outlet 4 of the inflow passage 41
4 communicates with an air guide port 45 opened in the cover case 23. This air guide port 45 is connected to the fixed driven pulley half 11 of the driven pulley 11. is facing the back of.

Incidentally, the inflow passage 41 may be formed outside the cover case 23.

A bowl-shaped draining plate 46 is fixed to the right end of the output shaft 9.
The outer peripheral edge of this drain plate 46 faces the air guide port 45. Fixed driven pulley half 11 of driven pulley 11
．． A suction fan 50 is provided on the back of the air cleaner A when the driven boob 9110 rotates.
The cooling air from c' passes through the inlet passage 41 and into the air guide port 45.
The cooling air is drawn into the scroll-shaped cooling air passage P in the transmission case 2.

In addition, the fixed drive pulley half of the drive pulley 10 is
A stirring blade 51 is provided on the back side of the stirring blade 5.
1 acts to agitate the cooling air introduced into the cooling air passage P and cause the cooling air to flow in its radial direction.

An intermediate portion of the bottom wall of the cover case 23 bulges downward, and an air exhaust port 53 is opened at the end face of the bulge 52 . As shown in FIG. 5.7.9, an air guide block 55 made of synthetic resin is fixed to the inside of the bulge 52 by a set screw 54, and the drive pulley 10 is attached to this air guide block 55. An air guide path 56 is formed that extends substantially in the radial direction, and the entrance of this air guide path 56 is connected to the cooling air path P.
, and its outlet communicates with the exhaust port 53. Therefore, the stirring blade 5 of the drive pulley 10
1, the cooling air flowing in the radial direction is directly guided into the air guide path 56 of the air guide block 55 with less resistance, and is discharged to the outside through the air outlet 53 with less resistance.

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

When the automatic continuously variable transmission T is driven by the operation of the engine, the driven pulley 11 is moved as shown by the solid line in Figs.
A suction fan 50 fixed to the fixed driven pulley half 11□ directs the cooling air from the air cleaner 4c to the inflow passage 4.
1 and sucked into the scroll-shaped cooling air passage P in the transmission case 2 from the air guide port 45. In this case, moisture mixed in the cooling air is blown away in the radial direction by the draining plate 46, hits the inner wall surface of the cover case 23, and is drained to the outside through a drain passage (not shown).

The cooling air from which moisture has been removed is forced to be sent in the radial direction of the driven pulley 11 by the suction fan 50, as shown in FIGS. The pressurized cooling air around the outer circumference of the driven pulley 11 is
The scroll-shaped cooling air passage P between the automatic continuously variable transmission T and the transmission case 2 flows toward the drive pulley 10, and the pulley 1
0 fixed drive pulley half 10. The stirring blade 5 provided in
1, while the V-belt 12 of the automatic continuously variable transmission T, the driven pulley 11, and the drive pulley 10
Effectively cools heat generating parts such as friction contact parts.

By the way, the cooling air passage P is formed in a scroll shape surrounded by the outer periphery of the continuously variable transmission T by the cover case 23, the air guide wall 43 formed on the inner surface thereof, and the gasket G. hardly sucks in the heated air that is convecting around the continuously variable transmission T, and can effectively suck and draw the cooling air from the air cleaner Ac. The cooling air that cools each part of the continuously variable transmission T is formed in the radial direction from the outer circumference of the drive pulley 10.
The air is also discharged to the outside through the air guide path 56 of the air guide block 55 with little resistance.

Of course, it can also be applied to institutions.

As described above, according to the present invention, the transmission case 2 connected to the cylinder block 1 is the case main body 2. A cover case 23 is fixed to the opening side of the case via a gasket G.
are fixed, and inside the cover case 23 are a drive pulley 10, a driven pulley 11, and their pulleys 1.
A continuously variable transmission T consisting of a V-belt 12 suspended between 0 and 11 is housed, and a cover case 23, an air guide wall 43, a gasket G, and an air driven pulley are arranged around the outer periphery of this continuously variable transmission T. 11 side is connected to the air guide port 45, and the drive pulley 10 side is connected to the air exhaust port 53. A bottom scroll-shaped cooling air passage P is formed which communicates with the air guide port 45 on the back side of the driven pulley 11. Since the suction fan 50 is provided for sucking in the air, it is possible to reduce the suction of hot air convecting around the continuously variable transmission T into the scroll-shaped cooling air passage P by the suction fan 50. The inflowing cooling air is guided to the outer periphery of the continuously variable transmission T with little resistance without being diffused, and is applied to various parts of the transmission T, especially the contact parts between the V-belt 12, the drive pulley 10, and the driven pulley 11, which are easily heated. The heat generating part can be effectively forcedly cooled. By shortening the distance between the crankshaft 5 and the output shaft 9, etc., even if the transmission case 2 is made more compact, it is possible to prevent excessive temperature rise inside the case 2. It is possible to prevent deterioration and extend its life.

Furthermore, the cooling air that has cooled the continuously variable transmission T is guided by the air guide path 56 in the radial direction of the drive pulley 10 and is discharged from the air outlet 53 with less resistance, reducing the resistance of the cooling air to be discharged and increasing the cooling effect. Further improvement can be achieved.

Further, the driven pulley 11 is rotated at a high speed as the engine speed increases, so the amount of cooling air sucked by the suction fan 5° increases as the rotational speed of the driven pulley 110 increases, that is, as the amount of heat generated by the heat generating section increases. It has good cooling efficiency and low fan loss.

[Brief explanation of the drawing]

Figure 1 is a side view of the internal combustion engine equipped with the device of the present invention mounted on the body frame of a motorcycle, and Figure 2 is the same as Figure 1.
Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 1, Figure 4 is a cross-sectional view taken along the TV-TV line in Figure J, and Figure 5 is a cross-sectional view taken along the line V-V in Figure 3. Figure 6 is a sectional view taken along the line VI-VI in Figure 5, Figure 7 is a sectional view taken along the line ■-■ in Figure 5, Figure 8 is a front view of the gasket, and Figure 9 is the cover. A perspective view of the case and gasket, Figure 10 is 1-x-
FIG. 2 is a side view of the main body of the case exposed to X-rays. G...Gasket, P...Cooling air passage, T...Continuously variable transmission, 1...Cylinder block, 2...Transmission case, 21
...Case main body, 23...Cover case, 5...
Crankshaft, 9... Output shaft, 10... Drive pulley, 11... Driven pulley, 12... V belt,
43... Air guide wall, 45... Air guide port, 50... Suction fan, 53... Air exhaust port, 56... Air guide path patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] ■ Transmission case (
2), a crankshaft (5) and an output shaft (9) are installed together, and the negative side of the transmission case (2) is provided with the crankshaft (5) and an output shaft (9).
5), a driven pulley (11) provided on the output shaft (9), and an endless V-bell (1) suspended between both pulleys (10, 11).
2) is provided with a continuously variable transmission (T), and the rotation of the crankshaft (5) is transmitted to the output shaft (9) via the continuously variable transmission (7''). In the internal combustion engine, the transmission case (2) has a force/<- case (23) fixed to the open side surface of the case main body (2I) via a gasket (G), and a force/<- case (23) is fixed in the cover case (23). houses the continuously variable transmission (T), and the continuously variable transmission (T) is housed in the continuously variable transmission (T).
The driven pulley (11) side is provided with an air guide port on the outer periphery of the driven pulley (11) by the cover case (23), the air guide wall (43) provided on the inner wall of the cover case (23), and the gasket (G). (45), a scroll-shaped cooling air passage (P) is formed in which the drive pulley (10) side communicates with the air exhaust port (53), and the guide Kazaguchi (45)
A cooling device for an internal combustion engine, characterized in that a suction fan (50) for sucking cooling air into the cooling air passage (P) is provided. (2) In the cooling device for an internal combustion engine according to claim 0, the cooling air passage CP> and the exhaust port (53) are connected to each other on the inner surface of the cover case (23). The aforementioned Drive Boo! J (10) and guide it in the radial direction of the air outlet (5).
3) A cooling device for an internal combustion engine, characterized in that an air guide path (56) is provided to allow air to flow out further.