JP2021076197A - Continuously variable transmission - Google Patents

Abstract

To compactly configure a V-belt type continuously variable transmission.SOLUTION: A continuously variable transmission 10 is equipped with a driving side pulley 12 supported by an input shaft 16, a driven side pulley 34 supported by an output shaft 38, a belt 32 wound between the driving side pulley 12 and the driven side pulley 34, and an actuator 50 configured to change the groove width of the driving side pulley 12 and driven by a motor 52. The actuator 50 is equipped with a planetary rolling mechanism type transmission device 80 as a mechanism for converting rotations of the motor 52 into linear motion in the groove width direction of the driving side pulley 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to a continuously variable transmission suitable for a vehicle, particularly a motorcycle such as a scooter.

Conventionally, in vehicles such as motorcycles, a V-belt type continuously variable transmission has been used in which a weight roller is used to automatically shift gears according to the engine speed. In recent years, for example, as the continuously variable transmission described in Patent Documents 1 and 2, it is also known that an electric motor is used instead of a weight roller as a driving means for changing the groove width of the drive side pulley. Has been done.

Japanese Unexamined Patent Publication No. 2016-151288 JP-A-2017-96339

In a continuously variable transmission that uses an electric motor as in the above patent document, the reduction gear for obtaining the required reduction ratio occupies a relatively large proportion in the casing of the continuously variable transmission, so that the continuously variable transmission is compact. There was a problem that it was difficult to convert.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a compactly configured V-belt type continuously variable transmission.

In order to solve the above problems, according to one embodiment of the present invention, the continuously variable transmission is a drive side pulley supported by an input shaft, a driven side pulley supported by an output shaft, and a drive side pulley. It comprises a belt wound between the drive side pulley and a driven side pulley, and an actuator driven by a motor configured to change the groove width of the drive side pulley, and the actuator rotates the motor on the drive side pulley. As a mechanism for converting the linear motion in the groove width direction of the continuously variable transmission, a continuously variable transmission is provided, which comprises a planetary rolling mechanism type transmission device.

According to this, in the actuator configured to change the groove width of the drive side pulley, by replacing the conventionally used reduction gear with a planetary rolling mechanism type transmission device, the actuator and eventually the continuously variable transmission can be replaced. It can be configured compactly.

Preferably, the actuator is controlled by a dedicated control unit. According to this, it is possible to replace only the actuator in the continuously variable transmission of the existing vehicle without the need to modify the ECU (Engine Control Unit) normally provided in the vehicle. Further, by using the signal from the ECU, the number of sensors installed in the continuously variable transmission can be reduced.

Preferably, the motor is orthogonally engaged to the actuator via a crown gear or bevel gear. According to this, the motor does not protrude in the vehicle width direction and can be easily stored in the casing, so that the width of the casing of the continuously variable transmission can be reduced.

Preferably, the weight roller is arranged on the movable pulley of the drive side pulley. According to this, by using a weight roller as an auxiliary when changing the groove width of the drive side pulley, the required output of the motor can be reduced, so that a smaller motor can be adopted.

According to the present invention, in an actuator configured to change the groove width of a drive-side pulley, by replacing a conventionally used reduction gear with a planetary rolling mechanism type transmission device, the actuator and eventually stepless speed change can be performed. The machine can be configured compactly.

It is the schematic sectional drawing of the V-belt type continuously variable transmission which concerns on one Embodiment of this invention. It is a figure which shows the structure of the actuator of FIG. It is an exploded perspective view of the planetary rolling mechanism type transmission device. It is a block diagram explaining the control in a local control unit. It is a figure which shows the operation mode of a continuously variable transmission. It is the schematic sectional drawing of the V-belt type continuously variable transmission which concerns on another embodiment of this invention.

Hereinafter, one embodiment for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a V-belt type continuously variable transmission 10 mounted on a vehicle such as a motorcycle according to an embodiment of the present invention. The continuously variable transmission 10 is arranged in a space surrounded by the transmission casing 30.

The continuously variable transmission 10 includes an input shaft 16 to which power is transmitted from an engine of a vehicle (not shown), and an output shaft 38 extending parallel to the input shaft 16. The input shaft 16 penetrates an insertion hole formed on the vehicle body side of the transmission casing 30, and is rotatably supported by a bearing 26 fitted in the insertion hole.

A drive-side pulley 12 is supported on the input shaft 16. The drive-side pulley 12 has a fixed sheave 12a fixed to the input shaft 16 and rotating integrally with the input shaft 16 and an axial direction (indicated by an arrow 22 in FIG. 1) with respect to the input shaft 16 supported by the input shaft 16. It is composed of a movable sheave 12b that is slidably configured in the direction).

The output shaft 38 penetrates an insertion hole formed on the vehicle body side of the transmission casing 30, and the bearing 46 fitted in the insertion hole and the bearing 48 fitted in the vehicle outside of the transmission casing 30. It is rotatably supported by. From the output shaft 38, rotational power is transmitted to the axle 42 via the reduction mechanism 40. Wheels (not shown) are fixed to the axle 42.

A driven side pulley 34 is supported on the output shaft 38. Like the drive-side pulley 12, the driven-side pulley 34 has a fixed sheave 34a that is fixed to the output shaft 38 and rotates integrally with the output shaft 38, and is supported by the output shaft 38 in the axial direction with respect to the output shaft 38. It is composed of a movable sheave 34b that is slidably configured. The movable sheave 34b is urged toward the fixed sheave 34a by the coil spring 44.

A V-belt 32 having a cross section adapted to the inclined surface of each of the fixed sheave and the movable sheave is wound between the drive side pulley 12 and the driven side pulley 34.

The continuously variable transmission 10 is further provided with an actuator 50 for driving the movable sheave 12b of the drive side pulley 12 to change the groove width of the drive side pulley 12. The actuator 50 is fixed to the transmission casing 30 by the actuator case 68. In the cylindrical portion 12b1 extending in the axial direction of the movable sheave 12b, a lever arm 24 for pushing or pulling the movable sheave 12b in the axial direction of the input shaft 16 can rotate relative to the cylindrical portion 12b1 via the bearing 25. It is connected. The lever arm 24 is slidably supported in the axial direction by the slider pin 28.

FIG. 2 is a detailed view of the actuator 50. The actuator 50 includes an electric motor 52, a planetary rolling mechanism type transmission device (also referred to as a planetary roller screw) 80 for converting the rotational motion of the motor into a linear motion in the groove width direction of the drive side pulley, and a planetary rolling mechanism. It includes a threaded spindle 54 that extends from the mold transmission device 80. The lower end of the lever arm 24 is connected to the tip of the threaded spindle 54 via a link 55 (see FIG. 1). The planetary rolling mechanism type transmission device 80 is rotatably supported by two bearings 60 and 62 with respect to the actuator case 68. The rotating shaft 52a of the electric motor 52 and the planetary rolling mechanism type transmission device 80 are rotationally engaged with each other via the bevel gears 64 and 66. A crown gear may be used instead of the bevel gear.

FIG. 3 is an exploded perspective view of the planetary rolling mechanism type transmission device 80. The planetary rolling mechanism type transmission device 80 itself is known to those skilled in the art, as disclosed in, for example, Japanese Patent Publication No. 2017-505601. In the planetary rolling mechanism type transmission device 80, a threaded spindle 54 having spirally continuous threaded grooves formed on the outer peripheral surface and a threaded groove facing the threaded groove of the spindle 54 are formed on the inner peripheral surface. It includes a set of nut halves 84, 87 and a plurality of planetary rollers 86 arranged between the threaded grooves of the spindle 54 and the threaded grooves of the nut halves 84, 87. The plurality of planetary rollers 86 are arranged along the outer periphery of the spindle 54, and each has a shaft extending parallel to the spindle 54, and the thread grooves thereof are the thread groove on the outer periphery of the spindle 54 and the nut halves 84, 87. It engages with both of the threaded grooves on the inner circumference of the wheel, and is rotatably intervened between the two.

The planetary rolling mechanism type transmission device 80 is further provided with two annular planetary disks 83 and 88. The planetary discs 83 and 88 are arranged on the outer sides of the nut halves 84 and 87 in the axial direction. The planetary discs 83 and 88 are formed with a through hole 83a for inserting the spindle 54 in the center thereof, and a plurality of roller support holes 83b are formed on the outer side thereof in the circumferential direction. The outer diameters of the planetary discs 83 and 88 are smaller than the inner circumferences of the nut halves 84 and 87. Both ends of each planet roller 86 are inserted into the roller support holes of the planet disks 83 and 88, respectively. Each planet roller 86 is rotatably supported by planetary discs 83, 88. Holding rings 82 and 89 are provided on the outer sides of the planet discs 83 and 88 in the axial direction, respectively, whereby the planet discs 83 and 88 are fixed to the inner peripheral sides of the nut halves 84 and 87. As a result, the planetary discs 83, 88 and the planetary roller 86 are prevented from being axially displaced with respect to the nut halves 84, 87. Therefore, the nut halves 84 and 87 and the planet roller 86 move as one relative to the spindle 54.

A distance washer 85 for applying a preload to the planetary roller 86 is interposed between the nut halves 84 and 87. Further, a bevel gear 66 that meshes with the bevel gear 64 is fixed to the nut half 87 (see FIG. 2).

In the planetary rolling mechanism type transmission device 80 configured as described above, when the nut half 87 is rotated by the electric motor 52, the relative rotational motion of the spindle 54 and the nut half 87 causes the planetary roller 86 to roll. The spindle 54 moves forward and backward in the axial direction. The planetary rolling mechanism type transmission device 80 has the advantages of a high reduction ratio and a compact configuration because the functions of both the reduction gear and the feed screw are integrated.

The rotating shaft 52a of the electric motor 52 and the spindle 54 of the planetary rolling mechanism type transmission device are engaged with each other at an angle of 90 degrees by using two bevel gears or crown gears. By tilting the electric motor 52 90 degrees with respect to the spindle 54 in this way, it is possible to avoid the electric motor from protruding in the vehicle width direction. However, the tilt angle of the electric motor with respect to the spindle may be any angle.

The actuator 50 is provided with a local control unit 58 for controlling the position of the movable sheave 12b of the drive side pulley 12.

FIG. 4A is a block diagram for explaining the control in the local control unit 58. The local control unit 58 receives a target position signal 72 of the movable sheave 12b and an engine speed 74 from an ECU 70 separately provided in a vehicle (not shown). The local control unit 58 is further obtained from the wheel rotation speed obtained from the rotation speed sensor 76 arranged adjacent to the axle 42 and the position sensor 78 arranged adjacent to the lower end surface of the lever arm 24. It receives the feedback signal of the sheave position and executes the control of the electric motor 52 based on these.

Alternatively, the local control unit 58 can also perform open loop control without utilizing the feedback signal of the movable sheave position, as shown in FIG. 4 (b).

Hereinafter, the operation of the continuously variable transmission 10 according to the present embodiment will be described.

When the input shaft 16 is rotated by an engine (not shown), the drive-side pulley 12 is rotated at the same time, and the rotation is transmitted to the driven-side pulley 34 via the V-belt 32 to rotate the output shaft 38 in the same direction.

The control unit 58 determines the amount of movement of the movable sheave 12b of the drive side pulley 12 based on the signals from each sensor, and gives the corresponding drive signal to the electric motor 52. The rotational motion of the electric motor 52 is decelerated by the planetary rolling mechanism type transmission device 80 and converted into a linear motion of the spindle 54, and the movable sheave 12b is moved in the axial direction of the input shaft 16 via the lever arm 24. ..

When the movable sheave 12b is moved toward the fixed sheave 12a in the drive side pulley 12, the groove width of the drive side pulley 12 becomes narrow and the winding diameter of the V belt 32 becomes large. Then, in the driven side pulley 34, the movable sheave 34b slides in the direction away from the fixed sheave 34a against the urging force of the coil spring 44 due to the tension of the V-belt 32. As a result, the groove width of the driven side pulley 34 becomes large, and the winding diameter of the V-belt 32 becomes small. Therefore, the rotation of the drive side pulley 12 is accelerated and transmitted to the driven side pulley 34.

When the movable sheave 12b is moved away from the fixed sheave 12a in the drive-side pulley 12, the groove width of the drive-side pulley 12 becomes wider and the winding diameter of the V-belt 32 becomes smaller. Then, in the driven side pulley 34, the tension of the V-belt 32 weakens, so that the movable sheave 34b slides toward the fixed sheave 34a by the urging force of the coil spring 44. As a result, the groove width of the driven side pulley 34 is narrowed, and the winding diameter of the V-belt 32 is increased. Therefore, the rotation of the drive side pulley 12 is decelerated and transmitted to the driven side pulley 34.

FIG. 5 is a graph showing the correspondence between the vehicle speed and the engine speed in a vehicle equipped with a continuously variable transmission. The graph shows a case where the continuously variable transmission is operated by using a weight roller which is a conventional technique, and a case where the continuously variable transmission according to the present embodiment is operated.

In the case of a continuously variable transmission of the prior art in which the reduction ratio is changed by using a weight roller, the relationship between the vehicle speed and the engine speed is fixed and cannot be changed (dotted line in FIG. 4). On the other hand, in the case of the present embodiment, the correspondence between the vehicle speed and the engine speed is as in the "eco mode" and the "sports mode" by controlling the movement amount of the movable sheave of the drive side pulley by the electric motor. Can be set in multiple ways. Therefore, various driving feelings can be set.

As described above, according to the present embodiment, in the actuator configured to change the groove width of the drive side pulley, by using the planetary rolling mechanism type transmission device instead of the reduction gear, the actuator and eventually the actuator, and thus the actuator, are used. The continuously variable transmission can be configured compactly. Moreover, since the number of parts is reduced, it is possible to reduce the manufacturing cost.

Further, since the local control unit is provided in the actuator and the electric motor is directly controlled by this control unit, it is not necessary to modify the ECU of the vehicle. Therefore, the actuator according to the present embodiment can be replaced with the actuator of the continuously variable transmission in the existing vehicle.

Further, since the electric motor constituting the actuator and the planetary rolling mechanism type transmission device can be arranged in parallel or perpendicular to each other, the degree of freedom in arranging the actuator in the casing is high.

Although the embodiments of the present invention have been described, the present invention is not limited to these embodiments, and various modifications and improvements can be made within the scope of the gist of the present invention described in the claims. Is.

In the above-described embodiment, the movable sheave of the drive-side pulley eliminates the centrifugally actuated weight roller used to change the groove width of the drive-side pulley in a conventional V-belt continuously variable transmission. The movable sheave is moved only by the actuator. However, it is also possible to provide a weight roller having the same configuration as the conventional one in the movable sheave so that the movement of the movable sheave is assisted by the actuator.

FIG. 6 is a schematic cross-sectional view of a V-belt type continuously variable transmission 100 mounted on a vehicle such as a motorcycle according to such an embodiment. The same configurations as those of the embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, an inclined surface 96 is formed on the back surface side of the movable sheave 12b'of the drive side pulley 12', and a guide plate 98 is further attached. In the space between the inclined surface 96 and the guide plate 98, a weight roller 94 is arranged so as to be movable in the radial direction of the sheave.

In the cylindrical portion 12b1'extending in the axial direction of the movable sheave 12b', a lever arm 90 for pushing or pulling the movable sheave 12b'in the axial direction of the input shaft 16 is provided with respect to the cylindrical portion 12b1' via the bearing 91. It is connected so that it can rotate relative to each other. The lever arm 90 is slidably supported in the axial direction by the slider pin 28. The lower end of the lever arm 90 is connected to a threaded spindle 54 extending from the planetary rolling mechanism type transmission device 80 via a link 92.

Similar to the conventional continuously variable transmission using a weight roller, as the rotation speed of the input shaft 16 increases, the centrifugal force acting on the weight roller 94 increases, and the weight roller 94 moves in the direction of the centrifugal force, that is, Since the movable sheave 12b'moves outward in the radial direction along the inclined surface 96, the movable sheave 12b'is pressed toward the fixed sheave 12a. The actuator 50 applies thrust to the movable sheave 12b'via the lever arm 90 in a direction that assists the thrust of the movable sheave 12b'by the weight roller 94. As a result, the groove width of the drive side pulley 12'is narrowed. On the contrary, when the rotation speed of the input shaft 16 decreases, the actuator 50 applies thrust to the movable sheave 12b'in the direction in which the movable sheave 12b'is separated from the fixed sheave 12a.

In this way, when the groove width of the drive side pulley is changed, by combining the thrust of the movable sheave by the weight roller and the thrust of the movable sheave by the actuator, it is possible to adjust the driving feeling to some extent and the movable sheave by the actuator. Since the thrust required for the movement of the electric motor can be suppressed, the size of the electric motor can be reduced. Therefore, it is advantageous when an inexpensive and power-saving continuously variable transmission is desired.

In the above-described embodiment, it has been described that the local control unit receives signals of engine output, engine speed, movable sheave position, and wheel speed to control the electric motor, but a configuration that does not use some signals. Is also possible. For example, it is possible to use open loop control that does not receive feedback on the movable sheave position, or it is possible to control the electric motor based only on the feedback of the engine output and the movable sheave position.

The continuously variable transmission of the present invention is not limited to that mounted on a motorcycle, and includes, for example, a tricycle, an all-terrain vehicle (ATV), a utility task vehicle (UTV), and other four-wheeled vehicles. It can also be installed in vehicles.

10 Continuously variable transmission 12 Drive side pulley 12a Fixed sheave 12b Movable sheave 16 Input shaft 24 Lever arm 30 Transmission casing 32 V belt 34 Driven side pulley 34a Fixed sheave 34b Movable sheave 38 Output shaft 40 Reduction mechanism 42 Axle 50 Actuator 52 Electric Motor 54 Spindle 56 Arm 58 Local control unit 80 Planetary rolling mechanism type transmission

Claims (5)

It ’s a continuously variable transmission.
The drive side pulley supported by the input shaft and
The driven pulley supported by the output shaft,
A belt wound between the drive side pulley and the driven side pulley,
An actuator driven by a motor, which is configured to change the groove width of the drive side pulley, and an actuator.
With
The actuator is a continuously variable transmission including a planetary rolling mechanism type transmission device as a mechanism for converting the rotation of the motor into a linear motion in the groove width direction of the drive side pulley. The continuously variable transmission according to claim 1, wherein the actuator is controlled by a local control unit. The continuously variable transmission according to claim 2, further comprising a sensor for detecting the position of the drive-side pulley, wherein the local control unit controls the motor based on a signal from the sensor. The continuously variable transmission according to any one of claims 1 to 3, wherein the motor is engaged in a direction orthogonal to the actuator via a crown gear or a bevel gear. The continuously variable transmission according to any one of claims 1 to 4, wherein a weight roller is arranged on the drive side pulley.

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