JP2620186B2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a first rotating body, a second rotating body, and a third rotating body each having a rotating surface. A continuously variable transmission for transmitting torque of a first rotating body to the second rotating body or the third rotating body, wherein the intermediate rotating body has a predetermined shaft.
Are rotated around the intermediate rotator and the respective
Stepless by changing the contact position with the rotating surface of
The invention relates to a continuously variable transmission in which the speed is changed .

[0002]

2. Description of the Related Art As a continuously variable transmission capable of continuously changing the rotational speed in both the forward and reverse directions from a speed ratio of 0 to infinity, a continuously variable transmission using a three-vertex trochoid curve rotating surface has been proposed (Japanese Patent Laid-Open No. Hei 2 (1994)). -31055). This continuously variable transmission employs a mechanism that automatically presses the input-side rotor having a trochoid curve rotation surface to the intermediate rotor by rotation of the input shaft, so that the intermediate rotor can be stopped when stopped. The position change is facilitated to facilitate selection of the gear ratio.

As this pressurizing mechanism, as shown in FIG.
The same publication discloses a structure in which a groove inclined in the circumferential direction is provided in the rotor 2 ′ and its support portion 29, and a ball 30 is fitted in the groove. In this structure, when the rotor rotates, the ball climbs up the slope of the groove, so that the rotor is pushed out, and its rotating surface is pressed against the intermediate rotor. However, with such a structure, there is a problem that it is difficult to control the dimensions of the inclined grooves individually and to manufacture them with high accuracy. That is, this groove must be machined with an accuracy of the order of microns, and if there is any dimensional variation, only a few balls, such as about two or three, will contact both inclined surfaces of the groove. As a result, there is a problem that the behavior of the rotor becomes unstable and torque cannot be transmitted stably.

Further, the publication discloses another structure as shown in FIG. The rotor 2 ′ is rotatably supported by bearings 32 via races 31. The outer peripheral portion of the bearing ring 31 on the rotor side is inclined, and conical rollers 33 having a conical vertex shorter than the distance to the central axis are interposed between the guide plates 34 in the circumferential direction. Is equipped. With such a structure, when the rotor 2 'rotates, the tapered rollers 33 rotate accordingly,
The tapered roller 33 moves to the smaller diameter side of the rotor in the radial direction due to the deviation of the conical vertex from the center. As a result, the rotor 2 ′ is pushed out by the inclined surface of the bearing ring 31. However, in such a mechanism, it is difficult to bring the tapered rollers into line contact with the inclined surfaces of the rotor and the bearing ring, and the tapered rollers are tilted due to point contact, resulting in unstable behavior. In particular, when there is a load change, the tapered rollers are twisted, and torque cannot be transmitted stably. Further, it is difficult to precisely process such a large number of tapered rollers and guide plates, and there is a difficulty in manufacturing such a structure.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a continuously variable transmission which can be easily manufactured and can transmit torque stably.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first rotating body, a second rotating body, and a third rotating body each having a rotating surface. Continuously variable transmission that transmits the torque of the first rotating body to the second rotating body or the third rotating body by bringing the intermediate rotating body into contact with the second rotating body.
Wherein the intermediate rotor is rotated about a predetermined axis.
Contact position between the intermediate rotating body and the respective rotating surfaces
Stepless change in which stepless speed change is performed by changing the position
In a speed changer, a supporting portion that supports the first rotating body so as to be freely rotatable and freely movable in the direction of the rotation axis thereof,
An input comprising: a screw portion formed integrally with the first rotating body; and an input shaft threaded portion for advancing the screw portion toward the intermediate rotating body when the screw portion is fitted and rotated in one direction. Axis and
It is characterized by having.

[0007]

According to the present invention, when the input shaft rotates in one direction by the above configuration, the rotation of the screw portion causes the input shaft to rotate.
A screw portion formed integrally with the first rotating body and fitted with the input shaft screw portion advances in the direction of the intermediate rotating body integrally with the first rotating body, and the rotating surface of the first rotating body becomes the intermediate rotating body. Contact. When the first rotating body comes into contact with the intermediate rotating body, it receives the rotation resistance of the output system via the intermediate rotating body, the relative rotation between the screw portion and the input shaft screw portion stops, and the first rotating body rotates at the intermediate rotating speed. Pressed against the body and stopped moving further. Then, the input shaft and the first rotating body are integrally connected via the screw portion, and the torque of the input shaft is transmitted to the intermediate rotating body. In this case, since the first rotating body is supported by the supporting portion so as to be freely movable and rotated in the axial direction, the above-described operation can be performed.

Next, when the rotation of the input shaft is stopped, the first rotating body and the intermediate rotating body are stopped while maintaining the pressure contact state due to the rotational resistance of the output system, or when the rotational inertia of the output system is large. The first rotating body is rotated from the output system through the intermediate rotating body, and due to the rotation resistance of the stopped input shaft, the screw part formed integrally with the first rotating body and the screw part of the input shaft , The first rotator retreats and separates from the intermediate rotator. However, in any case, when the input shaft rotates in one direction again, the above operation is repeated, and the torque of the input shaft is transmitted to the intermediate rotating body via the first rotating body.
On the other hand, when the input shaft rotates in the direction opposite to the one direction, the first rotator moves in a direction away from the intermediate rotator, so that torque is not transmitted. However, no inconvenience occurs because the reverse rotation on the output side is obtained by the transmission mechanism itself. In addition, as the screw portion formed integrally with the first rotating body, a threaded portion may be provided on the first rotating body itself, or a nut provided with a separate threaded portion may be provided and the first rotating body may be provided with the first rotating body. It may be fixed to the body.

If the first rotating body is pressed against or released from the intermediate rotating body by the advance and retreat of the screw, the movement is reliable, and the rotating surface of the first rotating body is not twisted. The torque is transmitted stably. Further, the press-contact mechanism can be easily manufactured by screw processing.

[0010]

1 and 2 show an overall structure of a continuously variable transmission according to an embodiment. First, the overall configuration of the apparatus will be described with reference to these drawings. In the casing 1, rotors 2, 3, and 4 as first, second, and third rotating bodies are rotatably supported by bearings 5, 6, and 7, respectively. Rotation surfaces 2a, 3a, 4 at the end portions of the respective rotors 2, 3, 4
a represents a three-vertex trochoid curve, which will be described below,
It is a curved surface rotated around 10. Then, an intermediate rotor 11 as an intermediate rotating body is provided so as to come into contact with all these curved surfaces during torque transmission. In this embodiment, the input torque of the input shaft 12 is transmitted to the rotor 2, and is taken out from the output shaft 15 via the intermediate rotor 11, the rotor 3, and the gears 13 and 14 as the output torque. In this embodiment, the rotor 4 merely presses and supports the intermediate rotor 11. However, it is also possible to adopt a structure in which a second output having a different rotation speed from the rotor 3 is taken out from the rotor 4.

The intermediate rotor 11 is shown in FIG.
1 is rotated from the position indicated by the solid line to the position indicated by the chain line in FIG. As a result, the rotation of the output side is changed from the state of normal rotation at the maximum speed to the state of the rotor 2.
The contact point between the motor and the intermediate rotor 11 is changed to a state in which the contact point is reversed at the maximum speed via 0 rotation on the central axis 8.

Next, a mechanism for pressing or separating the rotor 2 from the intermediate rotor 11 will be described. A bearing 5 is interposed in a housing 16 fixed to the casing 1, and the rotor 2 is supported by the bearing 5 so that the rotor 2 can rotate and move in the axial direction 8. In the rotor 2, a nut 17 having a screw portion 17 a as a screw portion formed integrally with the first rotating body is provided so as to rotate integrally with the rotor 2. However, a nut 1 having such a threaded portion
Instead of providing 7, the rotor 2 itself may be threaded. The input shaft 12 is provided with a screw 12a as an input shaft screw portion at a tip end thereof, which is fitted with a screw portion 17a. The input shaft 12 is rotatably supported by a bearing 19 interposed in a housing 18. Further, in the present embodiment, a preload spring 20 for providing a rotation resistance to the rotor 2 is provided.

When the input shaft 12 is rotated, for example, in the direction of arrow A by such a mechanism, the nut 17 advances in the direction of arrow B by the screw, and therefore the rotor 2 advances in the direction of the intermediate rotor 11 and presses against it. I do. Rotor 2 is intermediate rotor 1
1, the nut 17 no longer advances in the direction of arrow B, and the nut 17 and the rotor 2 are further integrally connected to the input shaft 12. The rotor 2 is supported by the bearing 5. It rotates and transmits its rotation torque to the intermediate rotor 11. In this embodiment, the preload spring 20 is provided, and the rotor 2
Is always urged to contact the intermediate rotor 11.
This is because even if the rotational inertia of the rotor 2 is small and the rotational resistance between the rotor 2 and the bearing 5 is small, while the rotational resistance of the screw portion is large, the rotor 2 is previously rotated in the intermediate rotation. When the input shaft 12 rotates, the rotor 2 is instantaneously advanced and brought into pressure contact with the intermediate rotor 11 when the input shaft 12 rotates.

Next, when the input torque of the input shaft 12 is lost and its rotation is stopped, when the rotational inertia on the load side is small, the rotor 2 receives rotational resistance from the load side via the intermediate rotor 11 and the rotor 2 And the intermediate rotor 11 is stopped in a state where it is pressed against. On the other hand, when the rotational inertia on the output side is large, when the input shaft 12 stops, the rotor 2 is rotated by the intermediate rotor 11 due to the inertial force of the output system, and the screw 17
A relative rotation occurs between a and 12a, and the rotor 2 and the intermediate rotor 11 maintain a contact state in a state where the rotor 2 is slightly retracted and the pressing force is reduced. Then, in the next rotation of the input shaft, the torque is transmitted immediately. Input shaft
12 rotates in the direction of arrow C when the rotor 2
There is no pressure contact force between the rotor and the intermediate rotor 11, and no torque is transmitted between them. However, as described later, forward rotation and reverse rotation on the output side are achieved by the transmission mechanism itself.

Next, the shapes of the rotating surfaces 2a, 3a, 4a of the rotors 2, 3, 4 and the surface of the intermediate rotor 11 will be described with reference to FIG. The rotation surfaces 2a, 3a, and 4a are rotation surfaces obtained by translating the three-vertex trochoid curves 2a ', 3a', and 4a 'outward by a distance t and rotating them around the center axes 8, 9, and 10, respectively. . The three-vertex trochoid curves 2a ', 3a', and 4a 'are obtained from a line segment connecting the center o of a circle 22 inscribed in the circle 21 and having a diameter of 1/2 of the diameter and a point s on the circumference. Link PQ equal to the diameter of the circle 21 connected to one end s of the crank arm os
Is formed when the crank arm os rotates in the opposite direction at half the rotational speed of the crank arm os. Such a three-vertex trochoid curve 2a ', 3a', 4a 'has an almost constant curvature and a radius of curvature 7r when the length of the crank arm os, that is, the radius of the circle 21, is r. Point 8a in the figure,
9a and 10a indicate the centers of curvature of the respective trochoid curves. The above-mentioned central axes 8, 9, 10 are lines connecting the respective centers of curvature 8a, 9a, 10a and the center o of the circle 22, and the angle between them is 120 degrees.

The surface of the intermediate rotor 11 is shaped like a disk having a cross section formed by a straight line separated by a distance t on both sides from the link PQ and a semicircle having a radius t centered on the points P and Q at both ends. Has become. With such a shape, when the rotating surface 2a rotates, the flat portion or the arc portion of the intermediate rotor 11 comes into contact with the rotating surfaces 2a, 3a, and 4a of the rotors 2, 3, and 4. The position of each contact surface changes as the center s point of the intermediate rotor 11 is rotated along the circumference of the circle 22, and the rotation speed of each rotation surface 2a, 3a, 4a changes. Stepless shifting is achieved.

The rotating surfaces that come into contact with each other as described above are, for example, the rotating surfaces of the rotors 2, 3, and 4 are spherical, and the intermediate rotor 11 is rotated in a grindstone having the same shape. By finishing the rotating surfaces, the surfaces can be formed so as to contact each other with high accuracy.

FIG. 4 shows an example of a speed change mechanism for changing the speed ratio by moving the intermediate rotor 11. Transmission mechanism 23
Is rotatably supported by the casing 1 as shown in FIG.
It rotates about a center axis oo as a predetermined axis also shown in FIG. A support arm 27 that rotates about the ss line is attached to a crank arm 26 corresponding to the crank arm os in FIG.
The intermediate rotor 11 is rotatably mounted on this via a bearing 28. In this case, the center of the intermediate rotor 11 is located on the ss line. With such a structure, the intermediate rotor 11 revolves around the ss line and revolves around the central axis oo, and changes its contact position with respect to the rotating surfaces 2a, 3a, 4a. The gear ratio changes.

FIG. 5 is an explanatory diagram of a gear ratio by the above-described speed change mechanism. When the intermediate rotor 11 is in the position of the solid line as shown, rotating surface 2a, the rotation radius at the contact point between the respective rotational surface and the rotation surface 3a of the intermediate rotor 11, respectively R _1, R _2, R ₃ , R _4, and the rotational speeds of the respective rotating surfaces are N ₁ , N ₂ , and N _{3. Since} the respective rotating surfaces have the same tangential speed at the contact point, R ₁ N ₁ = R ₂ N ₂ R ₃ N ₂ = R ₄ N ₃ Therefore, the rotation ratio N ₃ / N ₁ between the rotation surface 2a and the rotation surface 3a
_{Is, N 3 / N 1 = R} 1 R 3 / R 2 R 4 , and the maximum speed ratio at this time is obtained. If the pitch circle radii of the gears of the rotating body 3 and the output shaft 15 are R ₅ and R ₆ , respectively, the final speed ratio N ₄ / N ₁ between the input shaft 8 and the output shaft 15 is N ₄ / N ₁ = R ₁ R ₃ R ₅ / R ₂ R ₄ R ₆ , and a speed increase ratio of, for example, 2.8 is obtained.

Next, when the intermediate rotor 11 is rotated by 120 degrees around the point o by the transmission mechanism and reaches the position indicated by the dashed line, the intermediate rotor 11 passes through the zero transmission position and reversely rotates. At this time, the radii of rotation at the contact points of the rotating surface 2a, the intermediate rotor 11, and the rotating surface 3a are R ₁ ′ and R ₂ , respectively.
, R ₃ ′ and R ₄ ′, and the rotation speed of the rotating surface 2a is N ₁
', The rotational speed of the output shaft 15 N _4' When the final gear ratio N ₄ '/ N _1' of the above by the same calculation as in the case of normal rotation, the input shaft 8 and the output shaft 15, N ₄ ' _{/ N 1 '= R 1'R} 3'R 5' / R 2'R 4'R
₆ ′, and a reverse rotation reduction ratio of, for example, 0.56 is obtained.

[0021]

As described above, according to the present invention, the first rotating body is pressed against or released from the intermediate rotating body by the advance and retreat of the screw accompanying the rotation of the input shaft, thereby ensuring the movement thereof.
Torque can be stably transmitted to the intermediate rotating body without the rotating surface of the rotating body being twisted. Further, since the main part of the press-contact mechanism is formed by a screw, the processing is easy and the production of the continuously variable transmission can be facilitated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an entire configuration of a continuously variable transmission according to an embodiment.

FIG. 2 is a side view of the continuously variable transmission.

FIG. 3 is an explanatory diagram showing a shape of a rotating surface of the continuously variable transmission.

FIG. 4 is a perspective view showing a transmission mechanism of the continuously variable transmission.

FIG. 5 is an explanatory diagram for explaining a speed ratio of the continuously variable transmission.

6 (a) and 6 (b) are cross-sectional views showing an example of a conventional pressure contact mechanism of a continuously variable transmission.

FIG. 7 is a cross-sectional view illustrating another example of a conventional pressure contact mechanism of a continuously variable transmission.

[Explanation of symbols]

2, 3, 4 rotors (first, second, third rotating bodies) 2a, 3a, 4a rotating surface 5 bearing (supporting portion) 11 intermediate rotor (intermediate rotating body) 12 input shaft 12a screw portion (input shaft) Screw part) 17a Screw part (thread part integrally formed with the first rotating body) o-o central axis (predetermined axis)

Claims (1)

(57) [Claims] A torque of the first rotating body is brought into contact with an intermediate rotating body for speed change by contacting the rotating surfaces of the first rotating body, the second rotating body and the third rotating body each having a rotating surface with each other. Is transmitted to the second rotating body or the third rotating body, wherein the intermediate rotating body rotates around a predetermined axis.
Contact between the intermediate rotating body and the respective rotating surfaces
Continuously variable speed is achieved by changing the position
In the transmission , a support portion that supports the first rotating body so as to be freely rotatable and movable in the rotation axis direction, a screw portion formed integrally with the first rotating body, An input shaft provided with an input shaft screw portion for advancing the screw portion toward the intermediate rotating body when the screw portion is fitted and rotated in one direction.