JPH0217990Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field The present invention relates to a forced air cooling device for a belt type transmission housed in a power unit for a vehicle such as a motorcycle.

(2) Prior art A transmission case is provided on one side of the engine body, and in the transmission chamber of this transmission case, there is a drive pulley connected to the engine body, a driven pulley connected to the output shaft, and an endless transmission suspended between these pulleys. In a vehicle power unit housing a belt-type transmission made of a belt, outside air is forcibly introduced into the transmission case, whereby the belt-type transmission inside the transmission case is forcedly air cooled. The device is already known, for example, from Japanese Utility Model Application Publication No. 101047/1983.

(3) Problems to be solved by the invention However, in the conventional cooling device, the outside air intake passage is formed directly at the front of the transmission case.
There is a limit to increasing the passage area of the passage, and the flow rate of outside air taken into the transmission case tends to be insufficient, which causes a decrease in cooling efficiency, and the overall structure becomes complicated, increasing costs. There were problems such as getting high.

The present invention was developed in view of the above circumstances, and aims to improve cooling efficiency and simplify the structure by allowing a large amount of outside air to flow into the transmission case with low resistance. We have also made it possible to discharge efficiently.
It is an object of the present invention to provide a cooling device for the belt type transmission.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the invention provides a transmission case on one side of the engine body, and a transmission chamber in the transmission case has a transmission case for the engine body. In a vehicle power unit that houses a belt-type transmission that includes a drive pulley connected to a crankshaft, a driven pulley connected to an output shaft, and an endless transmission belt suspended between both pulleys, a fan is attached to the drive pulley. A suction port of the fan and an exhaust port for discharging a part of the air sucked into the transmission chamber from the suction port to the outside of the transmission case are provided in the outer wall of the transmission case, and the outer surface of the outer wall is A duct cover having an air intake port and an air exhaust port is attached to cover the intake port and the exhaust port, and between the duct cover and the outer wall of the transmission case, there is a duct cover having an air intake port and an air exhaust port. It is characterized by defining an air intake passage for guiding the introduced outside air to the suction port, and an air exhaust passage for guiding the air inside the transmission chamber discharged from the exhaust port to the exhaust port.

(2) Effects According to the above configuration, when the belt type transmission operates, the transmission case and the duct cover form the transmission case and the duct cover.
The outside air is introduced into the transmission chamber through a large-volume outside air introduction passage, and the belt-type transmission is efficiently cooled by the large-capacity cooling air.

Furthermore, the transmission case can be provided with an air exhaust passage with a relatively large passage area, and the opening position of the exhaust port of the passage can be relatively freely set without being restricted by the position of the exhaust port of the transmission case. That is, since it becomes possible to select the optimum position for air exhaust, the efficiency of air exhaust from the transmission case is increased.

(3) Examples Hereinafter, examples in which the present invention is applied to a motorcycle will be described with reference to the drawings.

A power unit P is suspended on the body of a motorcycle, and this power unit P is connected to an engine body 1.
The main body 1 includes a transmission section 2 adjacent to and connected to a lower portion of one side of the main body 1, and a rear wheel W supported at the rear of the transmission section 2.

The transmission part 2 extends rearward from the lower part of the engine body 1, and the transmission case 3 includes an outer wall 4 ₁ of the crankcase 4, a transmission cover 5 fixed to the rear part thereof with connecting bolts 7, and the outer wall 4. ₁ and a cover case 6 fixed to the outer surface of the mission cover 5 with a connecting bolt 8 via an elastic seal member 30. crank case 4
A crank chamber 9, which is a part of the engine body 1, is formed in the front part of the engine body 1, and a transmission chamber 10 is formed in the transmission case 3 adjacent to the crank chamber 9. A crankshaft 11 is horizontally suspended in the crank chamber 9 so as to be freely rotatable, and a crank pin of the crankshaft 11 is connected to the engine body 1 via a connecting rod 12.
A piston 14 that slides into the cylinder 13 is connected. Further, at the rear of the transmission case 3, a gear chamber 15 is formed by the rear of the outer wall ₄₁ of the crankcase 4 and the transmission cover 5, and an output shaft 16 parallel to the crankshaft 11 is formed in the gear chamber 15. It is suspended horizontally so that it can rotate freely.

The transmission chamber 10 of the transmission case 3 accommodates a transmission system, that is, a V-belt type automatic continuously variable transmission T and a reduction gear mechanism R, which will be described later. The continuously variable transmission T connects the crankshaft 11 and the output shaft 16,
Since it has a conventionally known structure, its structure will be briefly explained. A variable diameter drive pulley 17 is provided at one end of the crankshaft 11, and an output shaft 16
A variable diameter driven pulley 18 having a larger diameter than the driving pulley 17 is provided at one end, and an endless V-belt 19 is suspended between the pulleys 17 and 18. The drive pulley 17 is composed of a fixed drive pulley half 17 ₁ fixed to the crankshaft 11 and a movable drive pulley half 17 ₂ supported slidably in the axial direction on the crankshaft 11. The pulley half 17 ₂ is provided with a speed change weight roller 20 that receives centrifugal force and moves it in a direction closer to the fixed drive pulley half 17 ₁ . Further, the driven pulley 18 includes a fixed driven pulley half 18 ₁ fixed to a hollow pulley shaft 21 that is rotatably supported on the output shaft 16 and a fixed driven pulley half 18 1 that is slidably supported on the pulley shaft 21 in the axial direction. The movable driven pulley half 182 consists of a movable driven pulley half ₁₈₂ , and a movable driven pulley half 1
8 ₂ is a driven pulley half 18 ₁ fixed by a spring 22.
biased toward

A centrifugal clutch C for automatic starting is provided on the output shaft 16 and outside the driven pulley 18. This clutch C has a conventionally known structure, and when the rotational speed of the pulley shaft 21 exceeds a set value, the pulley shaft 21 is coupled to the output shaft 16 via the clutch C.

The gear chamber 15 is formed by the rear part of the outer wall ₄₁ of the crankcase 4 and the transmission cover 5, and a reduction gear mechanism R is incorporated in the gear chamber 15. The gear chamber 15 includes the output shaft 1
6. A reduction shaft 24 and an axle shaft 25 are horizontally mounted parallel to each other so as to be freely rotatable, and a drive gear 26 integrated with the output shaft 16 is meshed with a first reduction gear 27 integrated with the reduction shaft 24, and further connected to the reduction shaft 24. 24 and the second one
The reduction gear 28 is the third reduction gear 2 integrated with the axle 25.
It is engaged with 9. A half portion of the axle 25 protrudes outside the gear chamber 15, and the rear wheel W is fixed thereto. Therefore, when the crankshaft 11 is rotated by the operation of the engine body 1, the rotation is V
The signal is transmitted to the output shaft 16 via the belt-type automatic continuously variable transmission T and the centrifugal clutch C, and is further transmitted from there to the rear wheels W via the reduction gear mechanism R.

An alternator A is connected to an end of the crankshaft 11 on the opposite side from the continuously variable transmission T.

As clearly shown in FIG. 3, an elastic seal member 31 is provided on the outer surface of the outer wall ₄₁ of the crankcase 4.
A heat insulating plate 32 is fixed via a plurality of mounting bolts 33, and this heat insulating plate 32 is attached to the transmission chamber 1.
0. Further, the heat insulating plate 32 cooperates with the outer wall 4 ₁ of the crankcase 4 to define a wind guide passage 34 that is long in the front-rear direction between the transmission chamber 10 and the crank chamber 9. The front wall of the crankcase 4 has an air inlet 35 that communicates with the air guide passage 34.
is opened, and a filter 3 is installed in front of this air inlet 35.
6 is provided. At the rear and lower part of the air guide passage 34, on the bottom surface of the outer wall ₄₁ of the crankcase 4,
An air exhaust port 37 that communicates with the air guide passage 34 is opened, and above the air exhaust port 37 is an air exhaust wall 3 that extends integrally from the outer wall 4 ₁ of the crankcase 4.
8 is provided substantially horizontally, and this air exhaust wall 38 covers the upper part of the air exhaust port 37 and prevents droplets, dust, etc. from entering the air guide passage 34 from the air exhaust port 37. Therefore, when the vehicle is running, a portion of the running air that hits the front wall of the crankcase 4 flows through the air inlet 35.
The air flows into the air guide passage 34, flows backward through the air passage 34 as shown by arrow a in FIG. 3, and is then discharged to the outside through the air exhaust port 37. As a result, an insulating air layer made of cold air is formed between the crank chamber 9 and the transmission chamber 10, making it difficult for the heat generated by the operation of the engine body 1 to be transmitted to the transmission chamber 10, that is, the continuously variable transmission T. There is.

Fixed drive pulley half 17 of the drive pulley 17
A suction centrifugal fan 43 is integrally provided on the back surface of the pump ₁ , and an axial fan 44 is integrally provided on the outer peripheral surface of the movable drive pulley half ₁₇₂ . A suction port 40 is opened in the cover case 6 opposite to the suction port of the centrifugal fan 43 . Further, as clearly shown in FIG. 2, behind the driven pulley 18, an air outlet 45 is opened in the rear wall of the cover case 6, and just before this outlet 45, several baffle plates 46 ₁ , 46 are opened. ₂ are provided, and a detour passage 46 communicating with the discharge port 45 is formed by these baffle plates 46 ₁ and 46 ₂ .

As shown in FIGS. 1 and 3, the cover case 6
A duct cover 48 is attached to the front half of the outer wall of the duct with the connecting bolt 8 through a seal member 47 . As clearly shown in FIG. 7, this duct cover 48 is formed in a semi-elliptical shape when viewed from the side so as to coincide with the front half of the cover case 6, and the rear end edge is the same as the rear half of the cover case 6. It is formed in a concave arc shape so that it can fit into a part of the truncated conical bulge 6a. The duct cover 48 covers the suction port 40 and forms an air intake passage 49 that is long in the front-rear direction on the outside of the transmission case 10.

A substantially trapezoidal notch 50 is formed below the front-rear intermediate portion of the duct cover 48, and an air intake port 51 communicating with the air intake passage 49 is opened in this notch 50. In front of the air intake port 51, a filter element 52 is supported inside the duct cover 48 so as to cross the air intake passage 49. The outside air that has flowed in is filtered by this filter element 52. Further, behind the notch 50, the duct cover 48
An arcuate intermediate air exhaust passage 53 is defined inside the cover case 6, and an exhaust port 54 is provided in the cover case 6 to communicate the upper part of the air exhaust passage 53 with the inside of the transmission chamber 10. A discharge port 55 is provided in the lower wall of the duct cover 48 to communicate the air discharge passage 53 with the outside. The exhaust port 54
is open on the upper side of the V-belt 19, that is, on the tension side, to a zone Z where the V-belt 19 is away from the driven pulley 18, and the air that has cooled the driven pulley 18 passes through the exhaust port 54 to the intermediate The water is guided to flow into the discharge passage 53.

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

If the engine is running now, the crankshaft 11
The rotation of the vehicle is transmitted to the rear wheels W via the V-belt automatic continuously variable transmission T and the clutch C, and the gear ratio is automatically and variably controlled by the engine throttle operation and vehicle driving conditions as usual. Ru.

By the way, when the vehicle is running, the centrifugal fan 43 and the axial fan 44 are activated by the rotation of the drive pulley 17.
are driven together. Then, the cold outside air is drawn by the centrifugal fan 43 into the air intake passage 49 formed in the duct cover 48 through the air intake port 51 as shown by the arrow b in FIGS. After being filtered by the element 52, it is sucked into the transmission chamber 10 through the suction port 40.
The axial fan 44 also guides the cold air sucked into the transmission chamber 10 in the axial direction of the drive pulley 17. As a result, the heat generating portion of the drive pulley 17, that is, the contact portion between the pulley 17 and the V-belt 19 is effectively cooled by the cold air. The air that has flowed around the outer periphery of the drive pulley 17 flows rearward in the transmission chamber 10 along the continuously variable transmission T, cools the rear half of the transmission T including the drive pulley 18, and is then discharged from the rear air outlet 45. released to the outside.

By the way, as mentioned above, in the transmission chamber 10, the rotation of the drive pulley 17 causes cooling air to flow into the transmission chamber 1.
0 towards the rear, while the driven pulley 1
8 rotates in the counterclockwise direction in FIG. 2, the air flow generated by the rotation of the driven pulley 18 is directed toward the tension side of the V-belt 19, as shown by the arrow d in FIG. In the zone Z where the cooling air 19 is separated from the driven pulley 18, the air flows forward and opposes the aforementioned flow of cooling air flowing backward, causing a collision of the air flows there and causing the air to stagnate.
There, the air pressure tends to rise, but the zone Z
Since the exhaust port 54 is open, the pressurized air in the aforementioned zone Z passes from the exhaust port 54 through the intermediate air exhaust passage 53 as shown by the arrow c in FIGS. 55 to the outside. As a result, a large amount of air flows smoothly within the transmission chamber 10 without stagnation, and the continuously variable transmission T is effectively cooled even if the amount of heat generated increases due to the high-speed operation of the continuously variable transmission T.

C. Effects of the invention As is clear from the above embodiments, according to the invention, a fan is provided on the drive pulley of the belt type transmission housed in the transmission chamber in the transmission case, and the suction port of the fan and the An exhaust port for discharging a part of the air sucked into the transmission chamber from the suction port to the outside of the transmission case is provided in the outer wall of the transmission case, and the outer surface of the outer wall has an air intake port and an air discharge port. A duct cover is attached to cover the suction port and the exhaust port, and a duct cover is provided between the duct cover and the outer wall of the transmission case for guiding outside air introduced from the air intake port to the suction port. Since an air intake passage and an air exhaust passage for guiding the air in the transmission chamber discharged from the exhaust port to the exhaust port are defined, the transmission case does not have a particularly complex structure. It is possible to provide an air intake passage with a large air intake opening and a large passage area, and an air exhaust passage with an air exhaust opening and a large passage area, without having to change the opening positions of the air intake opening and the exhaust opening. can be relatively freely selected without being restricted by the positions of the above-mentioned suction port and exhaust port on the transmission case side, that is, the optimal position for intake and exhaust of outside air, and as a result, the transmission case Since the efficiency of sucking in outside air and discharging it can be significantly increased, it can greatly contribute to improving the cooling performance of the belt type transmission as a whole.

Furthermore, since the air intake passage and the air exhaust passage can be defined together between the outer wall of the transmission case and the common duct cover, the air intake passage and the air exhaust passage can be formed by specially modifying the internal structure of the transmission case. It can be easily obtained by simply adding the common duct cover, which can contribute to cost reduction.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a side view of the device of the present invention implemented in a power unit for a motorcycle; Fig. 2 is a partially cutaway enlarged side view of the device of the present invention; Figure 3 is a developed line sectional view of Figure 2, Figure 4 is an enlarged line sectional view of Figure 1, and Figure 5 is an enlarged line sectional view of Figure 1.
The drawings are an enlarged sectional view taken along the line in FIG. 1, FIG. 6 is an enlarged sectional view taken along the line in FIG. 1, and FIG. 7 is an internal view of the duct case taken along the line in FIG. T...Continuously variable transmission as a belt type transmission, 1
... Engine body, 3 ... Transmission case, 10 ...
Transmission chamber, 11... crankshaft, 16... output shaft,
17... Drive pulley as a drive pulley, 18...
...Followed pulley as a driven pulley, 19...V belt, 40...Suction port, 43...Centrifugal fan as a fan, 48...Duct cover, 49
...Air intake passage, 51...Air intake port, 53...
...air exhaust passage, 54...exhaust port, 55...exhaust port.

Claims (1)

[Scope of utility model registration request] A transmission case 3 is provided on one side of the engine body 1,
A drive pulley 17 connected to the crankshaft 11 of the engine body 1 is located in the transmission chamber 10 in the transmission case 3.
and a belt-type transmission T comprising a driven pulley 18 connected to the output shaft 16 and an endless transmission belt 19 suspended between both pulleys 17 and 18.
In the power unit for a vehicle, a fan 43 is provided on the drive pulley 17, and a suction port 40 of the fan 43 and a transmission chamber 1 from the suction port 40 are provided.
An exhaust port 54 for discharging a part of the air sucked into the transmission case 3 to the outside of the transmission case 3 is provided on the outer wall of the transmission case 3, and an air intake port 51 and an exhaust port 55 are provided on the outer surface of the outer wall. Duct cover 4 with
8 is attached to cover the suction port 40 and the exhaust port 54, and the air intake port 5 is disposed between the duct cover 48 and the outer wall of the transmission case 3.
an air intake passage 49 for guiding the outside air introduced from the air intake port 1 to the suction port 40;
1. A cooling device for a belt-type transmission in a vehicle power unit, characterized in that an air exhaust passage 53 is defined for guiding air to a vehicle.