JPH06185590A - Toroidal type continuously variable transmission - Google Patents

Abstract

PURPOSE:To provide a toroidal type continuously variable transmission to provide a high reduction gear ratio and hold high shift precision even during high load running. CONSTITUTION:A screw type control toroidal type continuously variable transmission comprises a reversible screw device arranged on the axis of each trunnion; a screw device support part to support each screw device to a housing rotatably around the axis of the trunnion; and a rotating device to rotate the screw device so that the trunnion is deviated in the axial direction of the trunnion to perform automatic gear shifting operation. The rotating device comprises a drive source to generate a rotation forced; a drive shaft which is rotatably supported to a housing and to which a rotation force from the drive source is transmitted; worm wheel gears 14 and 15 arranged on the drive shaft; and a pair of worm gear parts 18 and 19 arranged on the drive shaft and geared with the respective wheel gears and different in a twist direction from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to automobiles, industrial vehicles,
The present invention relates to a toroidal type continuously variable transmission used for motors and the like.

[0002]

2. Description of the Related Art A conventional toroidal type continuously variable transmission has a combination of a screw type control and a link mechanism as described in Japanese Patent Laid-Open No. 61-103052. This toroidal type continuously variable transmission has a control nut screwed to a screw shaft formed on the trunnion in order to axially deviate the trunnion that rotatably supports the power roller to perform an automatic shifting action. is doing. The control nut is connected to the speed change rod via a link. Therefore, the movement amount of the speed change rod is transmitted to the control nut as a rotation amount by the action of the link, and the control nut is rotated to displace the trunnion in the axial direction to perform the automatic speed change action.

[0003]

In the conventional toroidal type continuously variable transmission, the link connected to the nut portion of the control screw cannot have a strong link due to dimensional constraints. When I try to shift
There is a problem that the balance of the link itself is lost and one of the left and right links is abnormally changed, making gear shift control impossible. Further, at the time of assembly, there is a problem that it is difficult to determine the position of the link suitable for the gear shift neutral position, because the degree of freedom of the link is great. Furthermore, since the force ratio of the link changes depending on the span from the fulcrum, it is not possible to obtain a large force ratio (reduction ratio) within the limited size, and it is possible to add a further reduction mechanism or output the actuator. Had to be bigger. In addition, since the traction force applied to the power roller is reversely input to the link via the control screw, that is, the link is moved in the reverse direction by the control screw, the holding torque of the actuator must be maintained in order to hold the link in the predetermined position. Had to be quite large.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toroidal type continuously variable transmission which can obtain a large reduction gear ratio and can maintain high gear shifting accuracy even under a heavy load.

In order to solve the above problems, the present invention provides a housing, an input shaft and an output shaft that are rotatably and coaxially supported by the housing, and the shafts that are respectively inserted into the input shaft and the output shaft. An input disk and an output disk that rotate with it, and the opposing surfaces of the two disks cooperate with each other to form a toroidal cavity, and a pair of mating surfaces disposed in the toroidal cavity engage with the opposing surfaces of the two disks. A power roller, a trunnion that rotatably supports each power roller, and each trunnion that is rotatable about a trunnion axis that is substantially perpendicular to the rotation axis of the power roller and is movable along the trunnion axis. Trunnion support device for supporting the housing, reversible screw means provided on each trunnion axis, each of the above And screw means supporting device for supporting the trunnion axis line to rotatably said housing means Flip,
A toroidal type continuously variable transmission, comprising: a rotating device that rotates the screw means in order to shift the trunnion in the direction of the trunnion axis to perform an automatic shifting action. The rotating device generates a rotational force. A drive source, a drive shaft that is rotatably supported by the housing and transmits the rotational force from the drive source, a worm wheel gear that is provided on each of the screw means, and a worm wheel that is provided on the drive shaft. It is composed of a pair of worm gear portions that are meshed with each other and have different twist directions.

[0006]

According to the present invention, in order to perform the automatic gear shifting operation of the toroidal type continuously variable transmission, the gear shift control mechanism is provided with the drive shaft having two worm gear portions having different twisting directions, that is, the worm gear shaft and the worm wheel gear. The rigidity of is improved. As a result, reliable shift control is possible even when the load is high. Further, since the positional relationship between the worm wheel gear and the worm gear shaft that match the gear shift neutral position is determined by the meshing of the worm gears, positioning during assembly can be facilitated. Furthermore, since the speed is reduced by the worm gear, a larger speed reduction ratio can be set. Further, by setting the worm advance angle to a predetermined value, it is possible to prevent the traction force applied to the power roller from rotating the worm gear shaft in the reverse direction, so that the degree of freedom in setting the drive source, that is, the actuator can be increased.

[0007]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a sectional view in the trunnion direction of a first embodiment of a toroidal type continuously variable transmission according to the present invention, and FIG.
It is the figure which looked at the control screw part from the upper part.

The power roller 1 is disposed between the input disk 2 and the output disk 3 so as to press each other and engage with each other. The power roller 1 is rotatably supported by the trunnion 4 via an eccentric shaft 5. The upper and lower shaft ends of the trunnion 4 are held by the tension member 6 via a spherical outer surface bearing 7. The tension member 6 is supported by the housing 9 at its central portion via the post 8. Therefore, the trunnion 4 is rotatable about the trunnion axis Z-Z, and
A small amount of movement in the Z-axis direction is possible.

At the shaft end of the trunnion 4, there is formed a screw shaft 10 constituting a so-called reversible screw device which can be rotated by an axial force. A control nut 11 is screwed onto the screw shaft 10 via a ball 12. The control nut 11 is rotatably and axially fixedly supported by the housing 9 by the bearing 13. At the upper end of the control nut 11, the worm wheel gears 14 and 15 are attached to the bolt 1
It is fixed to the control nut 11 by 6. The worm wheel gears 14 and 15 mesh with the worm gear portions 18 and 19 of the worm gear shaft 17, respectively.

Next, the shifting method will be described. When the shift signal is sent to the actuator 20, the rotational force of the actuator 20 is transmitted to the worm gear shaft 17. Since the worm gear portions 18 and 19 of the worm gear shaft 17 have different twisting directions, the worm wheel gears 14 and 15
Rotate in opposite directions. Worm wheel gear 1
Since 4 and 15 are fastened to the control nut 11 by bolts 16, the left and right control nuts 11 rotate in opposite directions together with the worm wheel gears 14 and 15, respectively. When the control nut 11 rotates, the left and right screw shafts 10 screwed with the control nut 11 via the balls 12 move in mutually opposite directions along the trunnion axis ZZ. Since the screw shaft 10 is integrally connected to the trunnion 4, the power roller 1 supported by the trunnion 4 via the eccentric shaft 5 is displaced along the trunnion axis ZZ. When the power roller 1 is deviated along the trunnion axis ZZ, an automatic shifting action occurs in a well-known toroidal continuously variable transmission, and the power roller 1, and thus the trunnion 4, rotates about the trunnion axis ZZ. Since the direction of the rotation is so as to follow the rotation of the control nut 11, when the deviation of the trunnion 4 (power roller 1) returns to the original position as the lead of the screw shaft 10 returns to the neutral position, that is, the power roller. The rotation of the power roller 1 is stopped when the state in which the rotation axis of 1 and the input / output axis intersect is restored. That is, the automatic speed change operation is completed, and the speed can be changed to a desired speed ratio corresponding to the rotation amount of the worm gear shaft 17.

FIG. 3 is a view of the control screw portion of the second embodiment of the toroidal type continuously variable transmission according to the present invention as seen from above.
The toroidal type continuously variable transmission of FIG. 3 is a double-cavity type, and has a mechanism for driving four worm wheel gears by one worm gear shaft to change the speed. Two toroidal cavities are formed between the input disks 21 and 22 and the output disks 23 and 24, which are arranged opposite to each other. This double-cavity toroidal type continuously variable transmission can transmit twice the torque of the single-cavity type. 4 in these two cavities
Four trunnions are placed and 4 in relation to each trunnion
Two worm wheel gears 25, 26, 27 and 28 are provided. A worm gear shaft 29 is provided above the input discs 21 and 22.
Worm gears 30 and 31 are provided on the shaft 9. The worm gear unit 30 includes the worm wheel gears 25 and 2
7, and the worm gear portion 31 meshes with the worm wheel gears 26 and 28. Actuator 32
When the rotational force of the worm gear is transmitted to the worm gear shaft 29, the worm gear portions 30 and 31 have different twisting directions, so that the worm wheel gear 25 is opposite to 26 and the worm wheel gear 27 is opposite to 28. And the automatic shifting action occurs. At this time, the worm wheel gears 25 and 28 and the worm wheel gears 26 and 27 respectively rotate in the same direction.

FIG. 4 is a view of the control screw portion of the third embodiment of the toroidal type continuously variable transmission according to the present invention as seen from above.
The toroidal type continuously variable transmission of FIG. 4 is a double-cavity type, and has a mechanism for driving four worm wheel gears by two worm gear shafts to change the speed. Two toroidal cavities are formed between the input disks 33 and 34 and the output disks 35 and 36, which are arranged opposite to each other. Four trunnions are arranged in the two cavities, and four worm wheel gears 37, 38, 39 and 40 are provided in association with each trunnion. The worm gear shaft 4 is provided above the output disk 35.
A worm gear shaft 42 is provided above the output disc 36. The worm gear portion 43 of the worm gear shaft 41 meshes with the worm wheel gear 37, the worm gear portion 44 of the worm gear shaft 41 meshes with the worm wheel gear 38, the worm gear portion 45 of the worm gear shaft 42 meshes with the worm wheel gear 39, and the worm gear shaft 39. The worm gear portion 46 of 42 meshes with the worm wheel gear 40. A gear 47 is provided at one end of the worm gear shaft 41, and a gear 48 is provided at one end of the worm gear shaft 42. Actuator 49
Is transmitted to the gear 50, and the gear 50 moves to the gear 4
It meshes with 7 and 48 to transmit the rotational force to the worm gear shafts 41 and 42. The rotation speed of the actuator 49 is reduced by the gears 47, 48 and 50. Since the worm gear portions 43 and 44 of the worm gear shaft 41 and the worm gear portions 45 and 46 of the worm gear shaft 42 have different twisting directions, respectively, the worm wheel gear 37
For 38 and 40 for worm wheel gear 39
With respect to each other, they rotate in opposite directions, and the automatic speed change action occurs. At this time, the worm wheel gears 37 and 40
The worm wheel gears 38 and 39 rotate in the same direction.

1 to 4 show the embodiment of the toroidal type continuously variable transmission using the worm gear. Here, by setting the lead angle of the worm to 6 ° or less, the traction force generated between the power roller 1 and the disks 2 and 3 reverses the worm gear shaft 17 via the ball screw 12 and the worm wheel gears 14 and 15. Since the reverse rotation force that tries to turn to the back can be prevented by the self-lock mechanism peculiar to the worm, the worm gear shaft 17 is not rotated by the worm wheel gear. If all the advance angles are set to the same angle, the movement amount of each trunnion 4 is the same, and both the single cavity type and the double cavity type can be controlled.

[0015]

As described above, in the screw type toroidal type continuously variable transmission, since the worm mechanisms having different twisting directions from each other are adopted as the speed reducing mechanism from the actuator, a large reduction ratio can be set. Further, since the worm gear shaft can be prevented from reversing by the self-locking mechanism peculiar to the worm, the actuator can be downsized. Further, by adopting the worm mechanism, the rigidity of the shift control mechanism can be sufficiently secured, and reliable shift control can be performed. Even in a limited space, by designing the worm gear module, the amount of shift, the number of threads, the lead angle, and the number of teeth of the worm wheel gear, it is possible to drive four worm wheel gears with a single worm gear to create a double cavity toroidal type. The continuously variable transmission can also control the shift, and this system can be installed even in vehicles with large displacement. Then, by setting the worm advance angle to 6 ° or less, it is possible to prevent the worm gear shaft from being rotated in the reverse direction by the reverse driving force applied from the transmission itself, and to reduce the holding torque of the actuator to zero. It will be possible. Therefore, the amount of electric power supplied to the actuator can be reduced to a small amount or zero when the predetermined gear shift position is held constant, and energy can be saved. Further, the stability of the gear ratio with respect to the control signal is ensured. Furthermore, since the axial forces acting on the two worm gear portions of the worm gear shaft are opposite to each other, the force supporting the worm gear shaft in the axial direction is small, and the structure of the transmission is simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of a toroidal type continuously variable transmission according to a first embodiment of the present invention in a direction of a trunnion axis.

FIG. 2 is a view of the control screw portion of the first embodiment of the toroidal type continuously variable transmission according to the present invention as seen from above.

FIG. 3 is a view of the control screw portion of the second embodiment of the toroidal type continuously variable transmission according to the present invention as seen from above.

FIG. 4 is a view of the control screw portion of the third embodiment of the toroidal type continuously variable transmission according to the present invention as seen from above.

[Explanation of symbols]

1 Power Roller 2, 21, 22, 33, 34 Input Disc 3, 23, 24, 35, 36 Output Disc 4 Trunnion 9 Housing 10 Screw Shaft 11 Control Nut 14, 15, 25-28, 37-40 Worm Wheel Gear 17 , 29, 41, 42 Worm gear shaft 18, 19, 30, 31, 43 to 46 Worm gear portion 20, 32, 49 Actuator

Claims (1)

[Claims] 1. A housing, an input shaft and an output shaft which are rotatably and coaxially supported by the housing, and an input disk and an output disk which are respectively inserted into the input shaft and the output shaft and rotate together with the shaft. Opposing surfaces of the both disks cooperate with each other to form a toroidal cavity, and a pair of power rollers disposed in the toroidal cavities are engaged with the opposed surfaces of the both disks to rotate the power rollers. A trunnion that can be supported, and a trunnion support device that supports each of the trunnions on the housing so as to be rotatable about a trunnion axis that is substantially perpendicular to the rotation axis of the power roller and movably along the trunnion axis. Reversible screw means provided on each trunnion axis and each screw means are rotatable about the trunnion axis. A toroidal type continuously variable transmission comprising a screw means supporting device for supporting the housing on the housing, and a rotating device for rotating the screw means in order to shift the trunnion in the trunnion axial direction to perform an automatic speed change action. The rotating device includes a drive source that generates a rotational force, a drive shaft that is rotatably supported by the housing and that transmits the rotational force from the drive source, and a worm wheel gear that is provided on each of the screw means. And a pair of worm gear portions that are provided on the drive shaft and that mesh with the worm wheel gear and that have different twisting directions from each other, and a toroidal type continuously variable transmission.