JP2003130157A - Infinite variable-speed machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact infinite variable-speed machine, by which the interference between a belt or a tensioner and a variable-speed shaft can be prevented surely by promoting improvement in transmission efficiency, high accuracy of variable-speed control, compactness of a variable-speed motor and the saving of electric power, while shortening the center distance between a drive pulley and a driven pulley in the infinite variable-speed machine, using a dry belt. SOLUTION: There are provided with a drive pulley 11, a driven pulley 12, an endless dry belt 15 wound hanging in the space between both the pulleys, a tensioner 50 for obtaining the trust force of the belt by being disposed in the intermediate portion between the drive pulley and the driven pulley, by pushingly pressing the loose side of the belt, stroke mechanisms 14, 22 provided on the drive pulley and the driven pulley, respectively, and used to move a movable sheave in the axial direction by the rotational force, the variable-speed motor 40 and a transmission mechanism for transmitting the rotational force of the variable-speed motor to both the stroke mechanisms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission, and more particularly to a V-belt type continuously variable transmission for vehicles.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent No. 2548259, a drive pulley, a driven pulley, a metal belt wound between the drive pulley and the driven pulley, and at least one pulley are provided. The pressure adjusting mechanism that applies an axial force corresponding to the transmission torque, the stroke mechanism that is provided in each of the drive pulley and the driven pulley, that moves the movable sheave in the axial direction by the rotating force, and each stroke mechanism during the shift control There has been proposed a continuously variable transmission including a gear shift operating device that operates. This speed change operation device includes a speed change motor, an operation shaft having a pair of gears connected to respective stroke mechanisms of a drive pulley and a driven pulley, and a reversible transmission gear train connecting the motor and the operation shaft. It is provided with a device and an electromagnetic brake for holding the output shaft of the motor in a stopped state when the speed changing motor is not in operation.

However, since the metal belt is used as the belt, the friction coefficient μ with the pulley is very small,
Therefore, in order to obtain a predetermined transmission torque, it is necessary to provide a pressure adjusting mechanism such as a pressure adjusting cam mechanism on at least one of the pulleys. The pressure adjusting mechanism presses the fixed sheave of the pulley from behind, and makes the belt and the pulley come into strong contact with each other.This pressing force is transmitted to the stroke mechanism via the belt and the movable sheave, and a large load is applied to the stroke mechanism. Will be multiplied. As the stroke mechanism, for example, a screw mechanism such as a ball screw mechanism is used. However, when the screw mechanism is operated in the state where a large axial force is applied, it has a drawback that the wear is severe and the life is shortened. Further, since a large axial force is applied to the stroke mechanism, the required rotation torque becomes large, which causes an increase in the size of the speed change motor and an increase in power consumption. Therefore, even if the transmission efficiency of the reduction gear transmission is improved, it does not necessarily lead to downsizing of the speed change motor and power saving.

By the way, in addition to the above-described metal belt (wet belt), there is a dry belt having a friction surface such as resin or rubber on the contact surface with the pulley. In the case of a metal belt, since it is lubricated with oil, the friction coefficient μ with the pulley is low, and it is necessary to strongly press the belt by a pressure adjusting mechanism in order to obtain a predetermined transmission efficiency. On the other hand, the dry belt is not lubricated with oil, so the coefficient of friction with the pulley μ
Therefore, high transmission efficiency can be obtained without pressing the belt strongly with the pulley.

In a continuously variable transmission using such a dry belt, since the coefficient of friction between the pulley and the belt is high, instead of a pressure adjusting mechanism for applying an axial force corresponding to the transmission torque,
It is possible to provide a tension mechanism (for example, see Japanese Patent Laid-Open No. 4-46248) that presses the loose side of the belt to obtain the belt thrust.

[0006]

Therefore, in a continuously variable transmission having the drive pulley and the driven pulley provided with the stroke mechanism and the transmission mechanism for transmitting the rotational force of the speed change motor to each stroke mechanism as described above. By providing a tension mechanism for obtaining the belt thrust and using a dry belt as the belt, it is possible to improve the transmission efficiency, improve the accuracy of the speed change control, reduce the size of the speed change motor, and save power.

In the case of such a continuously variable transmission, if the operation shaft for transmitting the rotational force from the speed change motor to the stroke mechanism of each pulley is arranged outside the belt circumference, the axial distance between the drive pulley and the driven pulley can be shortened. However, since the gear provided on the operation shaft largely extends to the outside of the pulley, the transmission becomes large. On the other hand, when the operation shaft is arranged within the circumference of the belt, there is an advantage that the pulley and the gear can be arranged compactly, but the distance between the shafts of the drive pulley and the driven pulley becomes long and the device becomes large. Particularly, when the belt is pressed by the tension mechanism, there is a drawback that the belt and the operating shaft or the tension mechanism and the operating shaft are likely to interfere with each other.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to improve the transmission efficiency, to improve the accuracy of speed change control, to reduce the size of the speed change motor and to save power in a continuously variable transmission using a dry belt, and a drive pulley and a follower. An object of the present invention is to provide a small continuously variable transmission that can reliably prevent interference between a belt or a tensioner device and a transmission shaft while shortening the distance between the pulley shafts.

[0009]

In order to achieve the above object, the invention according to claim 1 has a drive pulley having a fixed sheave and a movable sheave axially movable with respect to the fixed sheave, and a fixed sheave. And a driven pulley having a movable sheave that is axially movable with respect to the fixed sheave, an endless dry belt wound between the drive pulley and the driven pulley, and each of the drive pulley and the driven pulley. A stroke mechanism for moving the movable sheave in the axial direction by a rotational force, a speed change motor, a transmission mechanism for transmitting the rotational force from the speed change motor to the stroke mechanisms, and a loose side of the belt. A continuously variable transmission including a tensioner device that presses to obtain a belt thrust, wherein each of the stroke mechanisms includes an input gear to which a rotational force is input, and the input gear. And a screw mechanism that converts the rotation of the gear into the axial movement of the movable sheave, and the transmission mechanism includes a transmission shaft having two transmission gears that mesh with the input gears of both the stroke mechanism of the drive pulley and the driven pulley. The continuously variable transmission shaft is disposed in the circumference of the belt, and is arranged at a position closer to the tension side of the belt than a straight line connecting the shaft centers of the driving pulley and the driven pulley. Providing a transmission.

The continuously variable transmission of the present invention is provided with a dry belt and a tensioner device, and transmits the rotational force of the gear shifting motor to the stroke mechanism of each pulley via a transmission mechanism to vary the gear ratio. . Since the rotation amount of the shift motor is directly converted to the axial movement amount of the movable sheave via the stroke mechanism, it is possible to control the shift ratio to a desired gear ratio with high accuracy. The transmission shaft that constitutes the transmission mechanism is provided with two transmission gears that mesh with the input gears provided in the stroke mechanisms of the drive pulley and the driven pulley, and the stroke shafts of both pulleys are synchronized by the transmission shaft. Can be activated. With this configuration, the axial force acting on the movable sheave of each pulley is converted into torque by the stroke mechanism, and the torque of both pulleys is transmitted as torque in opposite directions to the speed change shaft. The gear shifting operation can be performed with a small driving force.

In the present invention, since the dry belt is used, the coefficient of friction with the pulley is high and a high transmission efficiency can be obtained. Further, in order to obtain the belt thrust, a tensioner device is used to press the loose side of the belt, rather than applying a pinching force in the axial direction to the pulley. Therefore, no extra axial force acts on the stroke mechanism, and the stroke mechanism can operate smoothly. That is, the rotational force of the shift motor is converted into the axial movement of the movable sheave without waste through the transmission mechanism and the stroke mechanism. Therefore, the shift response is improved, and the Low return performance during sudden deceleration can be improved. For the same reason, the speed change motor can be downsized and its power consumption can be reduced.

The speed change shaft having two speed change gears meshing with the input gear of the stroke mechanism is arranged at a position closer to the tension side of the belt than the straight line connecting the shaft centers of the driving pulley and the driven pulley within the circumference of the belt. Has been done. That is, by disposing the speed change shaft within the circumference of the belt, the speed change shaft can be brought close to the drive pulley and the driven pulley,
The transmission mechanism can be downsized. However, when the transmission shaft is arranged on the straight line connecting the shaft centers of the drive pulley and the driven pulley, the distance between the two pulleys becomes long. Further, since the tensioner device presses the loose side of the belt, the belt or the tensioner device may interfere with the transmission shaft. Therefore,
In the present invention, the speed change shaft is arranged at a position closer to the tension side of the belt than the straight line connecting the shaft centers of the drive pulley and the driven pulley. As a result, the distance between the shafts of both pulleys can be shortened,
In addition, it is possible to prevent interference between the belt or tensioner device and the transmission shaft.

According to a second aspect of the present invention, the input gear of the stroke mechanism is connected via the movable sheave and the bearing so as to be relatively rotatable and axially immovable, and the input gear and the female screw member of the screw mechanism are fixed to each other. It is desirable that a male screw member that is screwed with the female screw member be fixed to the fixed portion, and the transmission gear be a gear having an axial length corresponding to the stroke of the movable sheave of each pulley. The stroke mechanism is a mechanism that converts a rotation input into an axial movement of a movable sheave, and a screw mechanism such as a ball screw mechanism can be used. There are various types of screw mechanisms, but the input gear is connected to the movable sheave and the bearing so as to be relatively rotatable and immovable in the axial direction,
When the input gear and the female screw member of the screw mechanism are fixed and the male screw member screwed with the female screw member is fixed to the fixing portion, the female screw member rotates and moves in the axial direction as the input gear rotates. Therefore, the input gear also moves in the axial direction while rotating. Therefore, the transmission gear that meshes with the input gear is a gear having an axial length corresponding to the stroke of the movable sheave. With the stroke mechanism having the above-described configuration, the structure is simplified and the input gear can be configured by a thin gear, so that the stroke mechanism can be reduced in size and weight.

According to a third aspect of the present invention, in the transmission case containing the drive pulley and the driven pulley, an air intake port is formed at a position close to the drive pulley, and an air discharge port is formed at a position close to the driven pulley. It is preferable that the air that has entered from the intake port is made to flow to the contact portion between the tensioner device and the belt along the rotation direction of the drive pulley and discharged from the air discharge port along the rotation direction of the driven pulley. In the case of a continuously variable transmission using a dry belt, the pulley and the belt generate heat due to the friction between the belt and the pulley, and therefore need to be air-cooled. In particular, the driving pulley is more likely to generate heat than the driven pulley. Further, since the belt is bent by the tensioner device, heat is also generated at the contact portion between the tensioner device and the belt. Therefore, the cool air entering from the air inlet is first applied to the drive pulley to cool it, and then the air is caused to flow to the contact portion between the tensioner device and the belt along with the rotation of the drive pulley to cool the contact portion. Finally, after cooling the driven pulley, air is exhausted from the air outlet according to the rotation of the driven pulley. With this configuration, the rotation of the drive pulley and the driven pulley can be used to smoothly flow the air from the air intake port to the air exhaust port, and the cooling efficiency is improved.

[0015]

1 to 7 show a specific structure of an example of a continuously variable transmission according to the present invention, and FIG. 8 shows its skeletal structure. This continuously variable transmission is an FF horizontal type transmission, and generally has a drive shaft 10 that supports an input shaft 3, a counter shaft 4, and a drive pulley 11 that are driven by an engine output shaft 1 via a starting mechanism 2. The driven shaft 20 supporting the driven pulley 21, the dry V belt 15 wound around the drive pulley 11 and the driven pulley 21, the reduction shaft 30, the output shaft 32 connected to the wheels, the speed change motor 40, the tensioner device 50, and the like. It is composed of. The input shaft 3, the counter shaft 4, the drive shaft 10, the driven shaft 20, the reduction shaft 30, and the output shaft 32 are all non-coaxial and arranged in parallel.

The starting mechanism 2 of this embodiment is composed of a clutch, a torque converter and the like. The input shaft 3 is rotatably supported by a transmission case 6 via bearings, and the input shaft 3 is provided with a forward-moving gear 3a that relatively rotates and a reverse-moving gear 3b that integrally rotates, and the forward-moving gear 3a is synchronized. The forward hub switching mechanism 5 is selectively connected to the clutch hub 3c fixed to the input shaft 3. The forward movement switching mechanism 5 uses the fork 7 to move the forward movement position D and the neutral position N.
And retreat position R can be switched to three positions.

The counter shaft 4 is provided with a gear 4a that meshes with the forward gear 3a and a gear 4b that meshes with the gear 10a fixed to the engine side end of the drive shaft 10 so as to rotate integrally. By appropriately setting the reduction ratios 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 belt driving.

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.
The stroke mechanism 14 is provided on the rear side of the V belt 15. The stroke mechanism 14 is disposed closer to the engine than the V belt 15. The stroke mechanism 14 of this embodiment is a ball screw mechanism that moves the movable sheave 11b in the axial direction by the speed changing motor 40, and the bearing 1 is attached to the movable sheave 11b.
Female screw member 14 rotatably supported via 4a
b and a male screw member 14c fixed to the transmission case 6
And a ball arranged between them, and the female screw member 1
A transmission gear (input gear) 14d is fixed to the outer peripheral portion of 4b. The transmission gear 14d is a resin gear having a diameter larger than that of the movable sheave 11b forming the drive pulley 11 and a thin wall.

The driven pulley 21 includes a fixed sheave 21a fixed on the driven shaft 20, a movable sheave 21b axially movably supported on the driven shaft 20, and a movable sheave 21b.
The stroke mechanism 22 is provided on the back side of the V belt 15. The stroke mechanism 22 is arranged on the side opposite to the engine side with respect to the V belt 15. This stroke mechanism 22 is also the drive pulley 11
Is a ball screw mechanism having a configuration similar to that of the stroke mechanism 14, and includes a female screw member 22b rotatably supported by the movable sheave 21b via a bearing 22a, a male screw member 22c fixed to the transmission case 6, and a space therebetween. And a ball arranged in the same manner, and a transmission gear (input gear) 22d is fixed to the outer peripheral portion of the female screw member 22b. The speed change gear 22d is also the movable sheave 2 that constitutes the driven pulley 21.
It is a resin gear with a diameter larger than 1b and a thin wall.

A reverse gear 24 is rotatably supported at a portion of the driven shaft 20 closer to the engine than the driven pulley 21, and the gear 24 meshes with a reverse gear 3b 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 drive switching mechanism 25. The fork 7 for operating the forward switching mechanism 5 is engaged with the reverse switching mechanism 25,
By operating the fork 7, both switching mechanisms 5 and 25 can be switched at the same time. That is, when the fork 7 is shifted to the right side 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 in the D position. At the intermediate position, the forward drive switching mechanism 5 and the reverse drive switching mechanism 25 are separated from the forward drive gear 3a and the reverse drive gear 24, respectively, and are in the N state. When the fork 7 is shifted to the left side in FIG. 8, the reverse drive switching mechanism 25 connects the clutch hub 26 and the reverse drive gear 3b, and the forward drive switching mechanism 5 is separated from the forward drive gear 3a, and thus is in the R position. In this way, since the forward switching mechanism 5 and the reverse switching mechanism 25 are operated with one fork 7, it is possible to eliminate the problem that the reverse switching mechanism 25 is in the R position when the forward switching mechanism 5 is in the D position.

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 30a fixed to the reduction shaft 30 and is formed integrally with the reduction shaft 30. It meshes with the ring gear 31a of the differential gear 31 via the gear 30b. And
The wheels are driven via the output shaft 32 provided in 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 10 a 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 30 a and 30 b of the reduction shaft 30, and the differential device 31.
It is housed in a gear chamber 6a formed on the engine side of the transmission case 6. The gear chamber 6a is lubricated with oil. On the other hand, the drive pulley 11 and the driven pulley 21 are arranged in the pulley chamber 6b of the transmission case 6 partitioned by the gear chamber 6a and the partition wall 6c. The pulley chamber 6b is a non-lubricated space.

The power transmission paths of the continuously variable transmission having the above-described structure when the vehicle is moving forward and backward are as follows. At the time of forward movement, the fork 7 is operated to move the forward movement switching mechanism 5 to the forward movement position D.
Switch to. The engine power input from the starting mechanism 2 to the input shaft 3 is the forward gear 3a, the counter shaft 4, the drive shaft 10, the drive pulley 11, the V belt 15, the 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, when moving backward, the fork 7
Is operated to switch the reverse drive switching mechanism 25 to the reverse drive position R. The engine power input from the starting mechanism 2 to the input shaft 3 is used for the reverse gears 3b and 24, the driven shaft 20, the reduction shaft 30,
It is transmitted to the output shaft 32 via the differential device 31. That is, when the vehicle retreats, power is transmitted without passing through the V belt 15.

As will be described later, a tensioner device 50 is provided for pressing the loose side of the V-belt 15 to apply belt tension, but the V-belt 15 reversely rotates during reverse travel,
Since the slack side is also reversed, the tensioner device 50 presses the tension side, and the V belt 15 is overloaded. However, in this embodiment, the torque is transmitted to the V-belt 15 only when moving forward, and the torque is not transmitted to the V-belt 15 when moving backward, so the tensioner device 50 is used.
Will always press the loose side of the V-belt 15,
The load on the V-belt 15 can be reduced and the life of the belt can be improved.

Next, the gear ratio variable mechanism in this continuously variable transmission will be described. The transmission motor 40 is provided on the outer side of the transmission case 6, particularly on a portion obliquely above the drive pulley 11.
Is attached. The speed change motor 40 is the brake 4
1 is a servo motor with an output gear 42 of the first
It meshes with a reduction gear 45 a provided at one end of the transmission 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. The gear 45b provided on the other end of the first speed-change shaft 45 is a spur gear or a helical gear having a length corresponding to the moving stroke of the movable sheave 11b of the drive pulley 11, and the gear provided on the drive pulley 11 is a gear. It meshes with the gear 14d. The first speed change shaft 45 and the gear 45
Both a and 45b are made of a metal material. When the gear 45b of the first transmission shaft 45 is rotated, the transmission gear 14d
The ball screw mechanism (stroke mechanism) 14 can move the movable sheave 11b in the axial direction by the following rotation. That is, the pulley groove width (belt winding diameter) of the drive pulley 11 can be continuously changed.

The speed change gear 14d of the drive pulley 11 also meshes with a first idler gear (speed change gear) 46a of a second speed change shaft 46 provided so as to span the transmission case 6, and further, a second idler gear of the second speed change shaft 46. 46b meshes with the transmission gear 22d of the driven pulley 21. These idler gears 46 a and 46 b are also the gears 45 of the first transmission shaft 45.
Like b, it is composed of a spur gear or a helical gear having a length corresponding to the moving stroke of the movable sheaves 11b and 21b. Second shift shaft 46 and idler gears 46a, 4
6b is made of a metal material. The second speed change shaft 46 is
As shown in FIG. 2, it is arranged between the drive pulley 11 and the driven pulley 21 and within the circumference of the V-belt 15. In particular, the second speed-change shaft 46 is arranged at a position closer to the tension side of the belt 15 than the straight line S (see FIG. 2) connecting the shaft centers of the drive pulley 11 and the driven pulley 21. The reason is that by arranging the drive pulley 11 and the driven pulley 21 at a position deviating from the straight line S connecting the shaft centers of the drive pulley 11 and the driven pulley 21, the distance between the shafts of the two pulleys can be shortened, and the tension roller 51 of the tensioner device 50, which will be described later, can be This is because the loosened side of 15 is pressed from the outside, so that the bent belt 15 and the second transmission shaft 46 do not interfere with each other. Particularly, since the position of the tension side of the belt 15 hardly changes depending on the gear ratio, it is possible to reliably prevent the interference with the second gear shaft 46. Further, the second speed change shaft 46 is connected to the belt 15
Of the transmission gears 46a,
6b can be miniaturized.

The rotational force of the speed-changing motor 40 is transmitted from the first speed-changing shaft 45 to the speed-changing gear 14d of the drive pulley 11 and further through the second speed-changing shaft 46 to the speed-changing gear 22d of the driven pulley 21.
Is transmitted to. Therefore, the movable sheave 11a of the drive pulley 11 and the movable sheave 21a of the driven pulley 21 can move in the axial direction while synchronizing with each other and mutually changing the pulley groove width (belt winding diameter) in the opposite direction. As described above, the gear mechanism (42, 45a, 42a, 45a, 42b) for transmitting the rotational force of the speed change motor 40 to the stroke mechanisms 14, 22 and mechanically connecting both the stroke mechanisms 14, 22 of the drive pulley 11 and the driven pulley 21. 45b, 14d, 4
6a, 46b, 22d), the position of the movable sheave, that is, the gear ratio is mechanically determined. Therefore, the gear ratio can be controlled with high accuracy only by the gear changing motor 40, and the gear ratio does not change due to temperature change or the like.

Of the gears forming the gear mechanism, only the speed change gears 14d and 22d are made of resin. Since the gear mechanism is arranged in the unlubricated pulley chamber 6b, it can be driven without lubrication by using the resin gears 14d and 22d. In addition, the transmission gear 14 that is a resin gear
Due to the deflection of d and 22d, the drive pulley 11 is subjected to sudden deceleration.
It is possible to delay the closing operation of the driven pulley 21 as compared with the opening operation thereof and improve the low return performance. The idler gears 46a and 46b and the gear 45b of the first speed change shaft 45 whose meshing position changes depending on the gear ratio.
Since it is made of a metal material, uneven wear can be prevented.

Further, the gear mechanism (42, 45a, 45b,
14d, 46a, 46b, 22d) are all constituted by circular reversible gears (spur gears, helical gears, etc.) having high transmission efficiency, and when the speed change motor 40 is not energized, the movable sheave of the movable sheave due to belt tension is The reaction force may rotate the gear train and change the gear ratio. However, dry belt 1
5, the reaction force of the movable sheave is small, and the rotation of the gear train can be prevented only by the starting resistance of the magnet built in the speed changing motor 40 when the motor is not energized.
In the above embodiment, for the sake of safety, the shifting motor 40
Although the brake 41 for stopping the rotation of the output gear 42 when the power is not supplied is provided, the brake 41 can be omitted.

Next, the mechanism for applying the belt tension to the V-belt 15, that is, the tensioner device 50 will be described.
As described above, the pulley groove width (belt winding diameter) of the pulleys 11 and 21 can be changed by the shifting motor 40.
With this alone, the transmission torque causes slippage between the V-belt 15 and the pulleys 11 and 21. So 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. The shaft 52a at one end of the link 52 is rotatably attached to the tip of the tensioner arm 52, and both ends of the central shaft 51a are fixed to the other end 52b.
The tension roller 51 is rotatably supported on the central shaft 51a via a bearing 51b.

As shown in FIG. 2, the tensioner arm 53
The rotary shaft 53a is provided near the radial outside of the drive pulley 11 (particularly at the upper position). The tensioner arm 53 is longer than the diameter of the drive pulley 11 and is curved along the outer peripheral surface of the drive pulley 11. The tension roller mounting portion 52a is arranged such that the rotation locus of the tension roller mounting portion 52a around the rotation fulcrum 53a of the tensioner arm 53 passes between the drive pulley 11 and the driven pulley 21. As described above, by providing the rotation fulcrum 53a of the tensioner arm 53 on the outer side in the radial direction of the drive pulley 11, in other words, by arranging the tensioner arm 53 at substantially the same position as the drive pulley 11 in the axial direction, Central axis 5
1a and the pivot fulcrum 53a of the tensioner arm 53 can be arranged at substantially the same position in the axial direction. That is, it becomes possible to support the central shaft 51a of the tension roller 51 without tilting, and it is possible to suppress the partial contact between the tension roller 51 and the V belt 15.

Since the tensioner arm 53 is curved along the outer peripheral surface of the drive pulley 11, the tensioner arm 5
3 does not interfere with the drive pulley 11. In addition, the tensioner arm 53 is longer than the diameter of the drive pulley 11, and the rotation locus of the tension roller mounting portion 52a is the drive pulley 1.
1 and the driven pulley 21, the interference between the tension roller 51 and the pulleys 11 and 21 can be suppressed. In particular, the V-belt 15 is stretched and worn as it is used, and the tension roller 51 and the V-belt 15
Although the contact position with the drive roller 1 changes greatly compared to the initial stage of use, the rotation locus of the tension roller mounting portion 52a is the drive pulley 1.
By arranging the tension roller 51 so as to pass between 1 and the driven pulley 21, the tension roller 51 can be arranged at a position where it is most unlikely to interfere with the pulleys 11, 21. That is, even when the link 52 is used, the deflection angle of the link 52 can be reduced and
The length of the link 52 can be shortened, and the supporting rigidity of the tension roller 51 can be secured.

An air intake port 60 for introducing cooling air into the pulley chamber 6b is provided at a position of the transmission case 6 facing the drive pulley 11 with the tensioner arm 53 interposed therebetween. That is, the air intake port 60 is formed in the front surface of the upper portion of the transmission case 6, that is, the portion facing the upper front side of the drive pulley 11. On the other hand, the air outlet 61
Is the lower rear surface of the transmission case 6, that is, the driven pulley 21.
Is formed on the lower rear side of the. An air inlet 60 and an air outlet 61 are formed on opposite sides of the pulleys 11 and 21.

As shown in FIG. 4, a hole 53d for passing cooling air is provided at a portion of the tensioner arm 53 facing the air intake port 60. A part of the cooling air that has entered from the air intake port 60 passes through the hole 53d of the tensioner arm 53 and hits the contact portion between the drive pulley 11 and the belt 15.
Therefore, the drive pulley 11, which is more likely to generate heat than the driven pulley 21, is cooled first. Then, due to the rotation of the drive pulley 11, the air flows to the contact portion between the tension roller 51 and the belt 15, and the tension roller 51 and the belt 1
5 is effectively cooled. The remaining part of the cooling air bypasses the tensioner arm 53 and flows in the pulley chamber 6b,
The belt 15 and the pulleys 11 and 21 are cooled. On the back surface of the movable sheave 21b of the driven pulley 21, fins 21c for generating an air flow from the air intake port 60 to the air discharge port 61 are provided. In particular, since the driven pulley 21 rotates at a higher speed than the drive pulley 11 during high-speed running when the belt 15 is most likely to generate heat, the fin 21c is provided on the driven pulley 21 so that the air intake port 6
An air flow from 0 to the air outlet 61 can be effectively generated. Therefore, a large amount of air can be circulated in the pulley chamber 6b, and the cooling efficiency can be improved. The air in the circulation of the belt 15 circulates as the belt 15 rotates, but heat is likely to be retained because there is little replacement of air with the outside of the belt 15. But,
In the present invention, the belt 15 is bent inward by the tension roller 51, and the second speed change shaft 46 is inserted in the circumference of the belt 15. Therefore, the air flow is obstructed by these members, and the replacement with the outside air is easy. become.
Therefore, the heat can be removed.

As shown in FIG. 7, the tensioner arm 53
Two shafts 53b and 53c are projectingly provided on the side surface of the tip end portion of one end, one end of the tension spring 54 is locked to one shaft 53b, and the other shaft 53c is extended and contracted to guide the 4 compression spring 57. One end of the guide 56 is rotatably connected. The tension spring 54 is located on the rear side of the fixed sheave 11a of the drive pulley 11 and between the drive shaft 10 and the driven shaft 20 and on the side opposite to the tensioner arm 53.
It is locked to a shaft 55 provided on the. Therefore, the tension force of the tension spring 54 causes the tension roller 51 to move to V
The tensioner arm 53 is rotationally biased in a direction of pressing the loose side of the belt 15 from the outer side to the inner side. By pressing the V-belt 15 from the outer side to the inner side in this way, a predetermined belt tension is obtained and the pulley 11,
The length of the V-belt 15 wound around 21 is increased to improve the transmission efficiency.

Expansion / contraction guide 56 for guiding the compression spring 57
The other end portion of is rotatably connected to a shaft 58 provided in the transmission case 6. The extension guide 56 has a compression spring 57.
The compression spring 57 is guided only in the expansion / contraction direction by the expansion / contraction guide 56 so that the compression spring 57 is not twisted or bent even if its direction changes.

Next, the operation of the belt pressing force of the tension roller 51 by the tension spring 54 and the compression spring 57 changing with the gear ratio will be described with reference to FIGS. 9 to 14. 9 shows the change in state at the maximum speed ratio, FIG. 10 shows the intermediate speed ratio, and FIG. 12 shows changes in belt tension when only the tension spring 54 is used, FIG. 13 shows only when the compression spring 57 is used, and FIG. 14 shows changes in belt tension when both springs are used together.

As is apparent from FIGS. 9 and 11, since there is no margin in the belt length at the maximum speed ratio and the minimum speed ratio, the amount of bending of the V-belt 15 by the tension roller 51 is small, and the tension roller 51 is the pulley 11. , 21 did not sink. On the other hand, in the intermediate gear ratio, since there is a margin in the belt length as shown in FIG. 10, the amount of bending of the V-belt 15 by the tension roller 51 is large, and the tension roller 51 sinks between the pulleys 11 and 21. Become.

A fulcrum 55 of the tension spring 54 on the transmission case side
Are located on the opposite sides of the V belt 15. Therefore, the spring force of the tension spring 54 acts in the direction in which the tension roller 51 presses the V belt 15 (P direction), and
As shown in FIG. 2, the belt tension by the tension spring 54 is the smallest at the intermediate gear ratio, and the difference in belt tension between the highest speed ratio and the lowest speed ratio and the intermediate gear ratio is large.

On the other hand, the compression spring 57 is arranged near the straight line L connecting the fulcrum 58 on the transmission case side and the swing fulcrum 53a of the tensioner arm 53. At the maximum speed ratio and the minimum speed ratio, the connection point 53c between the compression spring 57 and the tensioner arm 53 is located on the side opposite to the belt than the straight line L, and at the intermediate speed ratio, the connection point 53c is located on the belt side from the straight line L. is doing. Therefore, the compression spring 5
The spring force of 7 acts on the tension roller 51 away from the V belt 15 (M direction) at the highest speed ratio and the lowest speed ratio, and presses the V belt 15 at the intermediate speed ratio (P direction) (P direction).
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 (pulling side) at the maximum speed ratio and the minimum speed ratio.

Therefore, when the belt tensions of both springs 54 and 57 are added, the difference in belt tension between the maximum speed ratio and the minimum speed ratio and the intermediate speed ratio becomes small, as shown in FIG. can get. For example, when the belt tension in the intermediate gear ratio is set to the minimum necessary value (for example, 700 N) at which the V-belt 15 does not slip, 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 belt slippage and improvement of belt life.

The present invention is not limited to the above embodiment. In the above embodiment, the stroke mechanism is a ball screw mechanism, but it may be a normal screw mechanism in which a male screw member and a female screw member are directly screwed together. Further, although the male screw member is fixed and the female screw member is connected to the movable sheave via the bearing, conversely, the female screw member may be fixed and the male screw member may be connected to the movable sheave via the bearing. Other configurations can also be used.

In the tensioner device 50 of the above embodiment, the tension side 54 and the compression spring 57 are used to press the loose side of the V-belt 15. However, in addition to these springs, or in place of these springs, a motor or hydraulic pressure is used. The tensioner arm 53 may be rotationally biased by using an actuator such as a cylinder to press the V-belt 15. In this case, the belt tension can be arbitrarily controlled by controlling the actuator. When a motor is used, a rack is formed at the tip of the tensioner arm 53,
A pinion that meshes with this rack may be driven by a motor. When a hydraulic cylinder is used, the piston may be connected to the tensioner arm 53 and the tensioner arm may be rotationally biased. If a hydraulic cylinder is used, it should be installed outside the transmission case. The fulcrum of rotation of the tensioner arm 53 may be coaxial with the drive pulley or the driven pulley.

In the above embodiment, the rotational force of the speed change motor is transmitted to the drive side speed change gear provided in the stroke mechanism of the drive pulley in advance, and from this speed change gear is passed through the idler gear provided in the second speed change shaft. The transmission is transmitted to the driven side shift gear provided in the stroke mechanism of the driven pulley, but conversely, it may be transmitted to the shift motor, the driven side shift gear, the idler gear, and the drive side shift gear. However, as in Japanese Patent No. 2548259, the rotational force of the shift motor may be distributed to the drive side shift gear and the driven side shift gear via the shift shaft.

In the continuously variable transmission of the above embodiment, the belt thrust is applied only by the tensioner device, but the present invention is not limited to this, and an axial force is supplementarily applied to any one of the pulleys (eg, drive pulleys). A pressure adjusting mechanism may be provided.
A torque cam mechanism may be used as the pressure adjusting mechanism,
A spring may be used.

[0046]

As is apparent from the above description, claim 1
According to the invention of claim 1, in the continuously variable transmission using the dry belt, the rotational force of the speed change motor is transmitted to the stroke mechanism of both pulleys via the transmission mechanism and is driven synchronously. Control can be performed accurately and stably.
Further, since the belt thrust is not applied by the clamping force of the pulley but by the tensioner device that presses the loose side of the belt, the stroke mechanism is not overloaded. Therefore, it is useful for improving the life of the stroke mechanism, and the rotational force of the shifting motor is efficiently converted into axial movement of the movable sheave via the gear mechanism and the stroke mechanism, improving the shifting response and reducing the size of the shifting motor.
Power saving can be realized. Furthermore, since the speed change shaft is arranged within the circumference of the belt and is located closer to the tension side of the belt than the straight line connecting the shaft centers of the drive pulley and the driven pulley,
The transmission mechanism can be made compact, the distance between the shafts of the drive pulley and the driven pulley can be shortened, and the interference between the tensioner device and the transmission shaft can be prevented.

[Brief description of 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.

3 is a sectional view of a gear chamber of the continuously variable transmission of FIG.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a sectional view taken along line BB of FIG.

FIG. 6 is a partial cross-sectional view showing the tensioner device of the continuously variable transmission of FIG.

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 maximum speed ratio.

FIG. 10 is a diagram showing a contact position between a tension roller and a belt at an intermediate gear 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 showing a relationship between belt tension and a gear ratio when only a tension spring is used.

FIG. 13 is a diagram showing a relationship between belt tension and a gear ratio when only a compression spring is used.

FIG. 14 is a diagram showing a relationship between a belt tension and a gear ratio when a tension spring and a compression spring are used together.

[Explanation of symbols]

6 transmission case 10 Drive shaft (pulley shaft) 11 Drive pulley 14 Stroke mechanism 14d Drive pulley side input gear 15 V belt 20 Driven shaft (pulley shaft) 21 Driven pulley 22 Stroke mechanism 22d Driven pulley side input gear 40 speed change motor 46 Second gear shaft 46a, 46b speed change gear

Claims (3)

[Claims] 1. A drive pulley having a fixed sheave and a movable sheave axially movable with respect to the fixed sheave, and a driven pulley having a fixed sheave and a movable sheave axially movable with respect to the fixed sheave. An endless dry belt wound between the drive pulley and the driven pulley,
A stroke mechanism provided in each of the drive pulley and the driven pulley for moving the movable sheave in the axial direction by a rotational force, a speed change motor, and a transmission for transmitting the rotational force from the speed change motor to the two stroke mechanisms. A continuously variable transmission including a mechanism and a tensioner device that obtains a belt thrust by pressing the loose side of the belt, wherein each stroke mechanism includes an input gear to which a rotational force is input, and an input gear of the input gear. And a screw mechanism that converts rotation into axial movement of the movable sheave, and the transmission mechanism includes a speed change shaft having two speed change gears that mesh with input gears of both stroke mechanisms of the drive pulley and the driven pulley. The speed change shaft is disposed within the circumference of the belt, and is located at a position closer to the tension side of the belt than a straight line connecting the shaft centers of the drive pulley and the driven pulley. CVT, characterized in that is. 2. An input gear of the stroke mechanism is rotatably and axially immovably connected to the movable sheave via a bearing, and the input gear and an internal thread member of the screw mechanism are fixed to each other. The male screw member that is screwed with the female screw member is fixed to the fixed portion, and the speed change gear is a gear having an axial length corresponding to the stroke of the movable sheave of each pulley. Continuously variable transmission. 3. A transmission case for accommodating the drive pulley and the driven pulley has an air intake port formed at a position close to the drive pulley, and an air discharge port formed at a position close to the driven pulley. The air introduced from the intake port flows to the contact portion between the tensioner device and the belt along the rotation direction of the drive pulley, and is discharged from the air discharge port along the rotation direction of the driven pulley. The continuously variable transmission according to claim 1 or 2, characterized in that.