JP2003287110A - Cooling system for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system for a continuously variable transmission capable of effectively cooling an inner peripheral surface of a belt even if air is not sent into from an external part by an air blower, and dispensing with an enlargement of a shaft diameter. <P>SOLUTION: This continuously variable transmission can continuously vary the gear ratio by mutually changing a pulley groove width of both pulleys in the inverse direction by winding a dry belt 15 between a driving pulley 11 and a driven pulley 21. A straightening plate 70 having one end part existing in a pulley groove of the driven pulley 21, arranged in a revolving area of the belt 15, and straightening so that air flowing along the inner periphery of the belt 15 flows between the belt 15 and a pulley shaft 70, is fixed to a transmission case 6. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a continuously variable transmission, and more particularly to a device for air cooling a belt in a continuously variable transmission using a dry belt. is there. 2. Description of the Related Art Various types of continuously variable transmissions have been proposed and some of them have been put to practical use. The continuously variable transmission includes a driving pulley, a driven pulley, and a belt wound between the two pulleys. By changing the pulley groove widths of the driving pulley and the driven pulley in opposite directions, the stepless transmission can be steplessly changed. Variable. Therefore, there is no shift shock,
There is an advantage that smooth running can be realized. The continuously variable transmission includes a type using a wet belt (metal belt) and a type using a dry belt. The former drives the belt while lubricating it with oil, while the latter does not lubricate the belt and drives using the frictional force acting between the pulley and the transmission efficiency compared to the former. Is good. However, in the latter case, the belt generates heat due to frictional heat with the pulley and the bending of the belt, and the contact portion of the belt made of resin or rubber is deteriorated. [0004] Heat generation of the belt becomes a problem during high-speed running, which accounts for most of the running. Since the gear ratio during high-speed running is usually a high-speed ratio (High) state, the belt winding diameter of the driving pulley is large and the belt winding diameter of the driven pulley is small. If the belt winding diameter is small, the contact area between the belt and the pulley is small, so that slipping is likely to occur between the belt and the pulley, and the belt winding diameter is small and the bending of the belt is large, so it is easy to generate heat. . Since the outer peripheral surface of the belt is exposed to the outside, it is relatively easy to cool, but the inner peripheral surface of the belt is less likely to be filled with air from the outside, so that heat is easily stored. Accordingly, one problem is to effectively cool the inner peripheral surface side of the belt. FIG. 17 shows a relationship between a driven pulley and a belt in a high speed ratio state. The thick arrow indicates the rotation direction of the driven pulley P and the belt B, and the thin arrow indicates the flow of air. With the movement of the belt B, the air entrained along with the belt B collides with an airflow around the pulley shaft S, and an airflow (arrow X) flowing around the pulley shaft S is generated.
To effectively cool the inner peripheral portion of the belt B, the pulley shaft S
It is necessary to increase the airflow (arrow Y) passing between the belt and the belt B, but since the gap between the pulley shaft S and the belt B is narrow, most of the airflow flows along the arrow X and the airflow of the arrow Y Can not increase. Japanese Patent Application Laid-Open No. 9-280333 proposes a continuously variable transmission in which a ventilation hole through which cooling air passes is provided in an input shaft supporting a driving pulley or an output shaft supporting a driven pulley. I have. In this case, the inner peripheral surface of the belt can be effectively cooled by blowing cool air onto the belt from the shaft by the blower. However, in this case, not only another device such as a blower is required, but also a ventilation hole must be provided in the axis of the input shaft or the output shaft, which may lower the shaft strength. Therefore, there is a disadvantage that the shaft diameter must be increased, and the transmission becomes larger. It is an object of the present invention to provide a cooling device for a continuously variable transmission which can effectively cool the inner peripheral surface of a belt without having to blow in air from the outside with a blower or the like and does not need to increase the shaft diameter. Is to provide. [0008] In order to achieve the above object, according to the first aspect of the present invention, a dry belt is wound between a driving pulley and a driven pulley, and the pulley groove width of both pulleys is reduced. In the continuously variable transmission in which the speed ratio is steplessly variable by changing the gear ratio in the opposite directions, one end is disposed at least in the pulley groove of the driven pulley and in the circumference of the belt. A cooling device for a continuously variable transmission, wherein a rectifying plate for rectifying air flowing along a circumference to flow between a belt and a pulley shaft is fixed to a fixed member such as a transmission case. The most problematic in terms of heat generation is the inner peripheral portion of the belt wound around the driven pulley during high speed ratio running. In the present invention, one end portion is provided at least in the pulley groove of the driven pulley, and a rectifying plate disposed in the circumference of the belt is provided, and the airflow flowing with the belt collides with the airflow rotating around the pulley shaft of the driven pulley. The rectifier plate suppresses the disturbance and reduces the airflow flowing before the pulley shaft. Therefore, the air flowing along with the belt is smoothly guided between the pulley shaft and the belt, and the airflow (arrow Y in FIG. 17) passing between the pulley shaft and the belt can be increased. As a result, the inner peripheral portion of the belt can be effectively cooled. In the present invention, no special device such as a blower is required, and there is no need to provide a ventilation hole in the pulley shaft. Therefore, the structure is simplified, and it is not necessary to increase the shaft diameter. [0010] The current plate of the present invention is fixed to a fixing member such as a transmission case. The driven pulley is composed of a fixed sheave fixed to the pulley shaft and a movable sheave that can move in the axial direction with respect to the pulley shaft.Since these sheaves rotate at high speed, the shedding plate can be connected to these sheaves at any speed ratio. The shape must not interfere. Preferably, the current plate has a triangular shape tapering toward the pulley groove bottom in the same manner as the pulley groove shape. In this case, by arranging the side edge of the rectifying plate as close to the pulley surface of the fixed sheave as possible, the rectifying plate can be made as large as possible, and the rectifying effect can be enhanced. 1 to 7 show a specific structure of an example of a continuously variable transmission according to the present invention, and FIG. 8 shows a skeletal structure thereof. This continuously variable transmission is an FF horizontal-type transmission, and generally includes an input shaft 3 driven by an engine output shaft 1 via a starting mechanism 2, a counter shaft 4, a drive shaft 10 supporting a drive pulley 11, A driven shaft 20 for supporting the driven pulley 21, a dry V-belt 15 wound around the driving pulley 11 and the driven pulley 21, a reduction shaft 30, an output shaft 32 connected to wheels, a speed change motor 40, a tensioner device 50, and the like. It is composed of The input shaft 3, counter shaft 4, drive shaft 10, driven shaft 20, deceleration shaft 30, and output shaft 32 are all non-coaxial and arranged in parallel. The starting mechanism 2 of this embodiment is constituted by a clutch, a torque converter and the like. The input shaft 3 is rotatably supported by a transmission case 6 via a bearing. The input shaft 3 is provided with a forward gear 3a that rotates relatively and a reverse gear 3b that rotates integrally, and the forward gear 3a is a synchronous gear. It is selectively connected to a clutch hub 3c fixed to the input shaft 3 by a forward switching mechanism 5 of a type. The forward switching mechanism 5 is driven by a fork 7 to move the forward position D and the neutral position N
And the retreat position R. The counter shaft 4 is provided with a gear 4a that meshes with the forward gear 3a and a gear 4b that meshes with a gear 10a fixed to the engine-side end of the drive shaft 10 so as to be integrally rotatable. By appropriately setting the reduction ratio of the gears 4a and 4b of the counter shaft 4, the driving force is transmitted from the input shaft 3 to the drive shaft 10 at a reduction ratio suitable for driving the belt. The drive pulley 11 includes a fixed sheave 11a fixed on the drive shaft 10, a movable sheave 11b supported on the drive shaft 10 so as to be movable in the axial direction, and a movable sheave 11b.
, And the actuator 14 is disposed on the engine side of the V-belt 15. The actuator 14 of this embodiment is a ball screw mechanism that moves the movable sheave 11b in the axial direction by the speed change motor 40.
Female screw member 14 supported so as to be relatively rotatable via 4a
b, and a male screw member 14c fixed to the transmission case 6, and a transmission gear 14d
Has been fixed. The driven pulley 21 includes a fixed sheave 21a fixed on the driven shaft 20, a movable sheave 21b supported on the driven shaft 20 so as to be movable in the axial direction, and a movable sheave 21b.
And an actuator 22 provided behind the V-belt 15, and the actuator 22 is disposed on the side opposite to the engine with respect to the V-belt 15. This actuator 22 is also used as the drive pulley 11
A ball screw mechanism having the same configuration as that of the actuator 14, and includes a female screw member 22b rotatably supported on a movable sheave 21b via a bearing 22a, and a male screw member 22c fixed to the transmission case 6. A transmission gear 22d is fixed to an outer peripheral portion of the female screw member 22b. A reverse gear 24 is rotatably supported at a portion of the driven shaft 20 closer to the engine than the driven pulley 21. The reverse gear 24 meshes with a reverse gear 3 b fixed to the input shaft 3. . The gear 24 is selectively connected to a clutch hub 26 fixed to the driven shaft 20 by a reverse switching mechanism 25. The fork 7 for operating the above-described forward switching mechanism 5 is engaged with the reverse switching mechanism 25,
By operating the fork 7, both switching mechanisms 5, 25 can be switched simultaneously. That is, when the fork 7 is shifted rightward in FIG. 8, the forward switching mechanism 5 connects the clutch hub 3c and the forward gear 3a, and the reverse switching mechanism 2
5 is away from the reverse gear 24 and is at the D position. At the intermediate position, the forward switching mechanism 5 and the reverse switching mechanism 25 are separated from the forward gear 3a and the reverse gear 24, respectively, and are in the N state. When the fork 7 is shifted to the left in FIG. 8, the reverse switching mechanism 25 connects the clutch hub 26 and the reverse gear 3b, and the forward switching mechanism 5 is separated from the forward gear 3a. As described above, since the forward switching mechanism 5 and the reverse switching mechanism 25 are operated by one fork 7, the disadvantage that the reverse switching mechanism 25 is at the R position when the forward switching mechanism 5 is at the D position can be solved. A reduction gear 27 is formed integrally with the end of the driven shaft 20 on the engine side. The reduction gear 27 meshes with a gear 30 a fixed to the reduction shaft 30, and is formed integrally with the reduction shaft 30. And the ring gear 31a of the differential 31 via the gear 30b. And
The wheels are driven via an output shaft 32 provided on the differential device 31. The forward gear 3a of the input shaft 3, the reverse gear 3b, the forward switching mechanism 5, and the gears 4a, 4 of the counter shaft 4.
b, the gear 10a of the drive shaft 10, the reverse gear 24 provided on the driven shaft 20, the reverse switching mechanism 25, the reduction gear 27, the gears 30a and 30b of the reduction shaft 30, and the differential device 31
The transmission case 6 is housed in a gear chamber 6 a formed on the engine side. The gear chamber 6a is lubricated with oil. On the other hand, the drive pulley 11 and the driven pulley 21 are arranged in a pulley chamber 6b of the transmission case 6 partitioned by a gear chamber 6a and a partition 6c. The pulley chamber 6b is a non-lubricated space. The power transmission paths of the continuously variable transmission having the above-described structure at the time of forward movement and reverse movement are as follows. During forward movement, the fork 7 is operated to move the forward switching mechanism 5 to the forward position D.
Switch to The engine power input from the starting mechanism 2 to the input shaft 3 includes a forward gear 3a, a counter shaft 4, a drive shaft 10, a drive pulley 11, a V-belt 15, and a driven pulley 2.
1, transmitted to the output shaft 32 via the driven shaft 20, the reduction shaft 30, and the differential device 31. On the other hand, during reverse, the fork 7
To switch the reverse switching mechanism 25 to the reverse position R. The engine power input from the starting mechanism 2 to the input shaft 3 is transmitted to the reverse gears 3b, 24, the driven shaft 20, the reduction shaft 30,
It is transmitted to the output shaft 32 via the differential device 31. That is, power is transmitted without going through the V-belt 15 at the time of retreat. Next, the variable speed ratio mechanism in the continuously variable transmission will be described. The speed change motor 40 is provided on the outer side of the transmission case 6, in particular, a portion obliquely above the drive pulley 11.
Is attached. The speed change motor 40 is the brake 4
The output gear 42 is engaged with a reduction gear 45 a provided at one end of the first speed change shaft 45. The first transmission shaft 45 is provided so as to span the transmission case 6, and is housed in the pulley chamber 6b together with the output gear 42. A gear 45b provided at the other end of the first transmission shaft 45 is a spur gear having a length corresponding to a movement stroke of the movable sheave 11b of the drive pulley 11, and meshes with a transmission gear 14d provided on the drive pulley 11. I have.
When the gear 45b of the first speed-change shaft 45 is rotated, the speed-change gear 14d is rotated to follow, so that the movable sheave 11b can be moved in the axial direction by the action of the ball screw mechanism (actuator) 14. That is, the pulley groove width (belt winding diameter) of the drive pulley 11 can be continuously changed. The transmission gear 14d of the drive pulley 11 also meshes with a first idler gear 46a of a second transmission shaft 46 provided over the transmission case 6, and the second idler gear 46b of the second transmission shaft 46 is driven by a driven pulley. 21 is engaged with the transmission gear 22d. These idler gears 46
a and 46b are also the same as the gear 45b of the first transmission shaft 45,
It is constituted by a spur gear having a length corresponding to the moving stroke of the movable sheaves 11b and 21b. The second speed change shaft 46 is disposed between the driving pulley 11 and the driven pulley 21 and within the circumference of the V-belt 15 as shown in FIG. The rotational force of the transmission motor 40 is transmitted to the transmission gear 22d of the driven pulley 21 via the first transmission shaft 45, the transmission gear 14d of the drive pulley 11, and the second transmission shaft 46. Therefore, the movable sheave 11a of the driving pulley 11 and the movable sheave 21a of the driven pulley 21 can move in the axial direction while synchronizing with each other and changing the pulley groove width (belt winding diameter) in opposite directions. Next, a mechanism for applying a belt tension to the V-belt 15, that is, a tensioner device 50 will be described.
As described above, the pulley groove width (belt winding diameter) of the pulleys 11 and 21 is changed by the speed change motor 40.
If that is the case, slippage occurs between the V-belt 15 and the pulleys 11 and 21 due to the transmission torque. Then, V
A tensioner device 50 as shown in FIGS. 2 and 4 to 7 is provided in order to apply a belt tension that does not cause the belt 15 to slip. The tensioner device 50 includes a tension roller 51, and the tension roller 51
Is swingably supported by a tensioner arm 53 via a link 52. Shaft 52 at one end of link 52
a is rotatably attached to the tip end of the tensioner arm 52, a center shaft 51a is fixed to the other end 52b, and the tension roller 51 is rotatably supported on the center shaft 51a via a bearing 51b. As shown in FIG. 7, the tensioner arm 53
Two shafts 53b and 53c are protruded from the side surface of the distal end portion. One end of a tension spring 54 is locked to one shaft 53b, and the other shaft 53c is extended and contracted to guide a compression spring 57. One end of the guide 56 is rotatably connected. The tension spring 54 is inserted through the back side of the fixed sheave 11 a of the drive pulley 11, and the other end is locked by a shaft 55 provided in the transmission case 6. Therefore, the tension spring 54
Tension roller 51 causes the V-belt 1
The tensioner arm 53 is rotationally urged in a direction of pressing the loose side of 5 toward the inside. By pressing the V-belt 15 from the outside to the inside in this way, a predetermined belt tension is obtained, and the winding length of the V-belt 15 around the pulleys 11 and 21 is increased, thereby increasing the transmission efficiency. The other end of the telescopic guide 56 that guides the compression spring 57 is rotatably connected to a shaft 58 provided in the transmission case 6. A compression spring 57 is interposed in the expansion and contraction guide 56, and the compression spring 57 is guided only in the expansion and contraction direction by the expansion and contraction guide 56 so that the compression spring 57 does not twist or bend even if its direction changes. Next, the operation of the tension spring 54 and the compression spring 57 to change the belt pressing force of the tension roller 51 with the gear ratio will be described with reference to FIGS. 9 shows the state change at the highest speed ratio, FIG. 10 shows the state change at the intermediate speed ratio, and FIG. 11 shows the state change at the lowest speed ratio. 12 shows a change in belt tension when only the tension spring 54 is used, FIG. 13 shows a change in belt tension when only the compression spring 57 is used, and FIG. 14 shows a change in belt tension when both springs are used together. As is clear from FIGS. 9 and 11, there is no margin in the belt length at the highest speed ratio and the lowest speed ratio.
The amount of deflection of the V belt 15 by the tension roller 51 is small, and the tension roller 51 does not sink between the pulleys 11 and 21. In contrast, at the intermediate speed ratio, FIG.
Since the belt length has a margin as described above, the amount of deflection of the V belt 15 by the tension roller 51 is large, and the tension roller 51 sinks between the pulleys 11 and 21. A fulcrum 55 of the tension spring 54 on the transmission case side
Are located on the opposite side of the V-belt 15. Therefore, the spring force of the tension spring 54 acts in the direction (P direction) in which the tension roller 51 presses the V-belt 15, and FIG.
As shown in FIG. 2, the belt tension caused by the tension spring 54 is the smallest at the intermediate speed ratio, and the difference in belt tension between the highest speed ratio, the lowest speed ratio, and the intermediate speed ratio is large. On the other hand, the compression spring 57 is arranged near a straight line L connecting the fulcrum 58 on the transmission case side and the swing fulcrum 53a of the tensioner arm 53. At the highest speed ratio and the lowest speed ratio, the connection point 53 between the compression spring 57 and the tensioner arm 53 is determined.
c is located on the opposite side of the belt from the straight line L, and the connection point 53c is located on the belt side of the straight line L at the intermediate speed ratio. Therefore, the spring force of the compression spring 57 acts in the direction (M direction) separating the tension roller 51 from the V-belt 15 at the highest speed ratio and the lowest speed ratio, and presses the V-belt 15 at the intermediate speed ratio (P direction). ). That is, as shown in FIG. 13, the belt tension by the compression spring 57 is positive (pressing side) at the intermediate speed ratio, but negative (tensile side) at the highest speed ratio and the lowest speed ratio. Therefore, when the belt tensions of the two springs 54 and 57 are added, the difference in the belt tension between the highest speed ratio, the lowest speed ratio, and the intermediate speed ratio is reduced, as shown in FIG. can get. For example, when the belt tension at the intermediate speed ratio is set to a minimum value (for example, 700 N) that does not cause slippage of the V-belt 15, the maximum speed ratio and the minimum speed ratio can be suppressed to about 950 to 1000 N, resulting in excessive tension. Can be prevented. Therefore, it is possible to achieve both prevention of slippage of the belt and improvement of the life of the belt. Next, a cooling device in the continuously variable transmission will be described. As shown in FIG. 2, the rotation shaft 53 a of the tensioner arm 53 is provided radially outside (particularly, an upper position) of the drive pulley 11 and extends so as to cover the outer periphery of the drive pulley 11. At the position of the transmission case 6 facing the drive pulley 11 with the tensioner arm 53 in between,
An air intake 60 for taking in cooling air into the pulley chamber 6b is provided. That is, the air intake 60
Is formed on the upper front surface of the transmission case 6 (a portion facing the front side of the drive pulley 11) to take in the traveling wind. On the other hand, the air discharge port 61 is formed radially outward of the driven pulley 21 and opposite to the air intake port 60 with respect to the driven pulley 21, that is, on the lower rear surface of the transmission case 6. As shown in FIG. 4, a hole 53d for passing cooling air is provided in a portion of the tensioner arm 53 facing the air intake port 60. Therefore, the air intake 6
A part of the cooling air that has entered through the hole 53d reaches the contact portion between the drive pulley 11 and the belt 15 through the hole 53d of the tensioner arm 53, and the tension roller 51 and the belt 15
Also directly hits the contact part with. Therefore, the driving pulley 11
The belt 15 is cooled, and the tension roller 51, which is difficult to cool, is also effectively cooled. The rest of the cooling air flows in the pulley chamber 6b, bypassing the tensioner arm 53, and cools the belt 15. A fin 21c for generating an airflow from the air intake port 60 to the air discharge port 61 is provided on the back surface of the movable sheave 21b of the driven pulley 21. In particular, most belts 15
During high-speed running where heat is easily generated, the driven pulley 21 rotates at a higher speed than the driving pulley 11. By providing fins 21 c on the driven pulley 21, the airflow from the air intake 60 to the air exhaust 61 is reduced. It can be generated effectively. Therefore, a large amount of air can flow through the pulley chamber 6b, and the cooling efficiency can be improved. The belt 15 of the driven pulley 21
A rectifying plate 70 is provided to increase the cooling efficiency on the inner peripheral side of the rectifier. A rectifying section 72 which is one end of the rectifying plate 70
Is arranged in the pulley groove of the driven pulley 21 and in the circumference of the belt 15 as shown in FIGS. 2, 15 and 16. As shown in FIG. 15, the support portion 71, which is the other end of the current plate 70, is fixed to the transmission case 6 by bolts 73. The rectifying portion 72 has a triangular shape gradually narrowing toward the tip, and is formed so as to be radial in the pulley groove of the driven pulley 21 and to have a plane direction substantially parallel to the axial direction of the driven pulley 21. Has been inserted. One side edge 72a of the rectification section 72 is close to the fixed sheave 21a, and the other side edge 72b is
It is formed so as to be close to b. In other words, the rectifying plate 70 is formed in a shape that does not come into contact with the driven pulley 21 at any speed ratio and that can enhance the rectifying effect as much as possible. In FIG. 16, the thick arrow indicates the driven pulley 2
1 and the rotation direction of the belt 15, and the thin arrow indicates the flow of air. By arranging the rectifying plate 70 as described above, the air flowing along with the belt 15 is suppressed from colliding with the airflow rotating around the pulley shaft 20, and the air flowing along with the belt 15 is reduced with the belt 15 and the pulley shaft (driven shaft). Smoothly sent between 20. Therefore, the pulley shaft 20
The airflow (arrow Y) passing between the belt 15 and the belt 15 increases, and the belt 15 can be effectively cooled from the inner peripheral side. The present invention is not limited to the above embodiment. In the above embodiment, the example in which the rectifying plate is disposed only on the driven pulley side is described, but the rectifying plate may be disposed on the driving pulley side. As the dry belt used in the present invention, for example, as described in Japanese Patent No. 2500287,
It is desirable to use an endless tension band and a large number of blocks locked to the tension band, and to use a friction material such as a resin material or a rubber material in a contact portion of the block with a pulley. In the case of this type of dry belt, a large number of blocks have the effect of entraining the surrounding air to generate an air current, so that the blocks can be effectively cooled in combination with the current plate of the present invention. Further, the continuously variable transmission according to the present invention is not limited to the one in which the speed change motor and the tensioner device are used in combination as in the embodiment. However, when using a tensioner device that presses the loose side of the belt from the outside,
The flow straightening plate of the present invention is effective because the amount of air flowing into the inner peripheral side of the belt wound around the driven pulley in the high-speed ratio state tends to be insufficient. As is apparent from the above description, claim 1
According to the invention according to the present invention, the airflow flowing together with the belt is prevented from being disturbed by colliding with the airflow rotating around the pulley shaft by the rectifying plate, and the airflow flowing before the pulley shaft is reduced. The air flowing therewith is smoothly guided between the pulley shaft and the belt, so that the airflow passing between the pulley shaft and the belt can be increased. As a result, the inner peripheral portion of the belt wound around the driven pulley can be effectively cooled. Further, according to the present invention, no special device such as a blower is required, and there is no need to provide a ventilation hole in the pulley shaft.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a developed sectional view of an example of a continuously variable transmission according to the present invention. FIG. 2 is a sectional view of a pulley chamber of the continuously variable transmission of FIG. FIG. 3 is a sectional view of a gear chamber of the continuously variable transmission of FIG. FIG. 4 is a sectional view taken along line AA of FIG. 2; FIG. 5 is a sectional view taken along line BB of FIG. 2; FIG. 6 is a partial sectional view showing a tensioner device of the continuously variable transmission of FIG. 1; FIG. 7 is a perspective view of a tensioner arm. FIG. 8 is a skeleton diagram of the continuously variable transmission of FIG. FIG. 9 is a diagram showing a contact position between a tension roller and a belt at the highest speed ratio. FIG. 10 is a diagram showing a contact position between a tension roller and a belt at an intermediate speed ratio. FIG. 11 is a diagram showing a contact position between a tension roller and a belt at the lowest speed ratio. FIG. 12 is a diagram illustrating a relationship between a belt tension and a gear ratio when only a tension spring is used. FIG. 13 is a diagram illustrating a relationship between a belt tension and a gear ratio when only a compression spring is used. FIG. 14 is a diagram illustrating a relationship between a belt tension and a gear ratio when a tension spring and a compression spring are used together. FIG. 15 is a sectional view showing a positional relationship between a driven pulley and a current plate. FIG. 16 is a side view showing an airflow flowing together with a belt in a driven pulley. FIG. 17 is a side view showing an airflow flowing together with a belt in a driven pulley of a conventional example. [Description of Signs] 6 Transmission case 11 Drive pulley 15 V belt 20 Driven shaft (pulley shaft) 21 Driven pulley 70 Rectifier plate 72 Rectifier 73 Bolt

Claims (1)

Claims: 1. A speed change ratio is continuously variable by winding a dry belt between a driving pulley and a driven pulley, and changing the pulley groove widths of both pulleys in opposite directions. In the continuously variable transmission described above, one end is at least in the pulley groove of the driven pulley,
A rectifying plate arranged in the circumference of the belt and rectifying air flowing along the inner circumference of the belt so as to flow between the belt and the pulley shaft is fixed to a fixed member such as a transmission case. Cooling device for continuously variable transmission.