JP4604782B2 - Friction type continuously variable transmission - Google Patents

Description

  The present invention relates to a friction type continuously variable transmission, and more particularly to a friction type continuously variable transmission that is used as an industrial transmission, and particularly used in vehicles such as automobiles and two-wheeled vehicles.

  As a conventional friction type continuously variable transmission, a planetary type is known. Of the three planetary elements, the carrier is moved in the axial direction, and the contact point between the double cone as the planetary member, the sun member, and the ring member. Is changed, the rotation radius of the contact point is changed, and the gear ratio is changed steplessly (see, for example, Patent Documents 1 to 4).

  In the friction type continuously variable transmission 100 described in Patent Document 1, as shown in FIG. 5, a double cone 103 in which an input shaft 101 and an output shaft 102 are arranged concentrically and two cones are back-to-back, The carrier 104 is supported so as to be movable in the axial direction of the output shaft 102. On the two conical surfaces of the double cone 103, a ring member 105 provided on the input shaft 101 and a sun member 106 provided on the output shaft 102 have slopes formed in accordance with the slope of the cone surface. , Pressure contact. In the double cone 103, the contact bus with the ring member 105 and the contact bus with the sun member 106 are parallel to each other and slightly inclined with respect to the input / output shafts 101 and 102.

When the carrier 104 is moved in the axial direction, the double cone 103 keeps the contact point between the ring member 105 and the sun member 106 and moves slightly on the support shaft in the axial direction while the ring member 105 and the sun member are moved. The contact point with 106 is changed. As a result, the contact radius at each contact point changes, and the rotation of the output shaft 102 is changed.
Japanese Utility Model Publication No. 6-80944 Japanese Utility Model Publication 3-7566 Japanese Utility Model Publication No. 3-55948 JP-A-2-195053

  Incidentally, in the friction type continuously variable transmission 100 described in Patent Document 1, in the double cone 103, the contact bus with the ring member 105 and the contact bus with the sun member 106 are in relation to the input / output shafts 101 and 102. Although slightly inclined, the cone centers of the contact buses do not coincide with each other, and spin loss occurs at either contact point.

  Further, in the planetary friction type continuously variable transmission, the planetary member and the sun member are in convex and convex contact with each other, so that the contact surface pressure is increased and the product life may be shortened. On the other hand, since the planetary member and the ring member are in contact with each other by unevenness, the contact surface pressure is lowered, and the friction coefficient of the oil film may be lowered and slipping may occur. Therefore, in such a friction type continuously variable transmission, it is desired to lengthen the contact portion on the sun member side and shorten the contact portion on the ring member side.

  However, in the friction type continuously variable transmission 100 of FIG. 5, the contact point with the solar member 106 also moves because the double cone 103 moves. For this reason, in order to earn a contact length, a length that takes into account the amount of movement is required, and the conical surface of the solar member 106 must be greatly extended, resulting in an increase in the size of the device and a higher spin loss. turn into. For this reason, the contact length of both the solar member 106 and the ring member 105 is shortened, and there is a problem that the double cone 103 is likely to skew together with the above problem.

  The present invention has been made in view of such circumstances, and its purpose is to prevent spin loss and to reduce the contact surface pressure with the solar member to extend the life, and to make contact with the ring member. An object of the present invention is to provide a friction type continuously variable transmission having a planetary member with a stable posture in which surface pressure is increased and slip does not occur.

The above object of the present invention can be achieved by the following constitution.
A housing, an input shaft provided concentrically with respect to the housing and having a conical outer peripheral surface, and concentric with the input shaft so as to be rotatable relative to the input shaft and movable in the axial direction An output ring, a plurality of intermediate rollers that are arranged between the input shaft and the output ring and that can be brought into rolling contact with an outer peripheral surface of the input shaft and an inner peripheral surface of the output ring, and the output ring A ring drive device that moves in a direction ,
Each of the intermediate rollers is provided at a central portion in the axial direction so as to be inscribed in the output ring, and provided on both sides in the axial direction of the concave portion so as to circumscribe the outer peripheral surface of the input shaft. Two conical surfaces having a conical center coinciding with the conical center of the outer peripheral surface , and the contact bus of the recessed portion is disposed so as to be parallel to the central axis of the input shaft. Friction type continuously variable transmission.

According to the friction type continuously variable transmission of the present invention, each intermediate roller is provided at a central portion thereof in the axial direction and inscribed in the output ring, and provided on both sides in the axial direction of the concave portion and provided on the outer periphery of the input shaft. Since there are two conical surfaces that circumscribe the surface and have a conical center that coincides with the conical center of the outer peripheral surface of the input shaft, there is no spin loss, and the input shaft is used to obtain sufficient contact length with the input shaft. The contact surface pressure can be lowered and the life can be extended. Further, since the intermediate roller is supported at three points, the posture can be stabilized.
Furthermore, each intermediate roller has a contact bus in the recess inscribed in the output ring that is parallel to the central axis of the input shaft and is in point contact with the output ring, so that the contact surface pressure with the output ring is sufficiently increased, There is no slip.

  Hereinafter, a friction type continuously variable transmission according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view taken along line II of FIG. 2, showing a friction type continuously variable transmission according to an embodiment of the present invention. FIG. 2 is a sectional view of FIG. 1 showing the friction type continuously variable transmission. FIG. 3 is a sectional view taken along the line III-III of FIG. 2 of the friction type continuously variable transmission. FIG. 4 is a sectional view of the friction type continuously variable transmission. It is sectional drawing which shows the state to perform.

  The friction type continuously variable transmission 10 includes an input shaft 11 that is a sun member, a plurality of intermediate rollers 12 that are planetary members, an output ring 13 that is a ring member, a main body unit 15 in which a ring driving device 14 is incorporated, and an output shaft. And an output shaft unit 17 that rotatably supports 16.

  The main unit 15 includes a stepped cylindrical housing main body 18 and a cover member 19 attached to the large-diameter base end opening of the housing main body 18, and the output shaft unit 17 is a cover opposite to the housing main body 18. An output shaft housing 20 that closes the opening of the member 19 is provided, and the housing body 18, the cover member 19, and the output shaft housing 20 constitute a housing 21 of the friction roller type transmission 10.

  The housing body 18, the cover member 19, and the output shaft housing 20 are each made of steel or aluminum alloy, and the housing body 18 and the cover member 19, and the cover member 19 and the output shaft housing 20 each have a plurality of bolts (see FIG. Fixed to each other).

  The input shaft 11 is inserted into the housing 21 through a through hole 18a formed at a substantially central portion of the housing body 18, and is rotated through a thrust ball bearing 22 provided in the through hole 18a. It is supported freely. The input shaft 11 is urged in the axial direction with an appropriate pressing force by a preload spring 23 that contacts the side surface of the fixed ring 22 a of the thrust ball bearing 22, and the contact surface between the input shaft 11 and the intermediate roller 12. The pressure contact force is given to. Further, an oil seal 24 is provided between the outer peripheral surface of the input shaft 11 and the housing body 18 to seal the inside of the housing 21 from the outside.

  The distal end portion 11a of the input shaft 11 is formed in a truncated cone shape whose diameter decreases toward the distal end, and the outer peripheral surface of the distal end portion 11a constitutes a conical surface 11b. On the other hand, a drive shaft constituting a rotation shaft of an electric motor (not shown) is provided at the outer end portion (right end portion in FIG. 1) of the input shaft 11 so as to be integrally rotatable.

  Further, the output ring 13 is accommodated inside the cover member 19 so as to be movable in the axial direction via a ring driving device 14 disposed in the cover member 19. The output ring 13 is formed in a stepped cylindrical shape, and a female spline portion 13a such as a ball spline or a square spline is formed on the small-diameter inner peripheral surface, and at the tip of the large-diameter inner peripheral surface. A contact portion 13b with the intermediate roller 12 is provided. The contact portion 13b is formed in an elliptical cross section so as to make the contact surface with the intermediate roller as small as possible.

  The ring drive device 14 of the present embodiment includes a speed change motor 50, a worm gear, and a ball screw. The worm shaft 25 constituting the worm gear is connected to a transmission motor 50 provided outside the housing 21 and rotates integrally with the transmission motor 50. A worm wheel 26 that meshes with the worm shaft 25 is formed on the outer peripheral surface of a ball nut 27 constituting a ball screw, and the ball nut 27 is rotated to the cover member 19 by a pair of rolling bearings 28 and 29 arranged at both ends. Supported as possible. Further, spiral grooves 27a and 30a are formed on the inner peripheral surface of the ball nut 27 and the outer peripheral surface of the screw shaft 30 constituting the ball screw, respectively, and between these spiral grooves 27a and 30a. Three rows of balls 31 are arranged. On the inner peripheral surface of the screw shaft 30, an axial groove 30 b that accommodates the head of the detent pin 32 fixed to the outer peripheral surface of the output shaft housing 20 so as to be relatively movable in the axial direction is formed up to one end opening. . Further, a rolling bearing 35 fixed in the axial direction by retaining rings 33 and 34 is arranged between the inner peripheral surface on the other end side of the screw shaft 30 and the outer peripheral surface on the small diameter side of the output ring 13. Thereby, the output ring 13 is movable in the axial direction together with the screw shaft 30 and is supported so as to be rotatable relative to the screw shaft 30.

  Accordingly, when the worm shaft 25 is rotated by driving the speed change motor 50, the ball nut 27 on which the worm wheel 26 is formed rotates, and the rotation of the ball nut 27 is converted into the axial movement of the screw shaft 30 via the ball 31. To do. As a result, the output ring 13 supported by the screw shaft 30 via the rolling bearing 35 moves in the axial direction. When the drive of the speed change motor 50 is stopped, the output ring 13 is maintained at a desired position by the worm gear.

  Further, three intermediate rollers 12 are arranged between the front end portion 11 a of the input shaft 11 and the output ring 13 in the vicinity of a position that is equally spaced in the circumferential direction. Each intermediate roller 12 includes a roller body 36 and a pair of pivot shafts 37 and 38 formed integrally on both end surfaces in the axial direction of the roller body 36, and the pair of pivot shafts 37 and 38 are formed in the housing body 18. The support hole 18b and the support hole 39a provided in the cap 39 fixed to the housing body 18 are rotatably supported via radial needle bearings 40 and 41.

  The roller body 36 circumscribes the conical surface 11b of the tip end portion 11a of the input shaft 11 at both ends in the axial direction, and is provided in a pair of conical surfaces 36a and 36b configured by a single conical shape and in the central portion in the axial direction. Thus, a recess portion 36d having a conical surface 36c inscribed in the contact portion 13b of the output ring 13 is provided.

The conical centers of the pair of conical surfaces 36 a and 36 b of the intermediate roller 12 are arranged so as to coincide with the conical center of the conical surface 11 b of the tip end portion 11 a of the input shaft 11, and the inner diameter of the output ring 13 is larger. The contact generatrix of the conical surface 36c of the recess 36d inscribed in the contact portion 13b on the peripheral surface is set to be parallel to the central axes of the input shaft 11 and the output shaft 16. Accordingly, as the output ring 13 is driven in the axial direction by the ring driving device 14, the large-diameter inner peripheral surface of the output ring 13 always moves in the axial direction with a constant pressure contact force with the outer peripheral surface of the recess portion of the intermediate roller. .
The output ring 13 and the intermediate roller 12 generate a pressure contact force by shrink fitting.

  As shown in FIGS. 2 and 3, the cap 39 that supports one pivot 37 of the intermediate roller 12 has three stepped bolts 42 provided between the intermediate rollers 12 adjacent to each other in the circumferential direction. The cap 39 and the housing main body 18 are stamped and fitted into the housing main body 18 to be positioned in the axial direction and the circumferential direction with respect to the housing main body 18.

  On the other hand, in the output shaft unit 17, the output shaft 16 is rotatably supported in a through hole 20 a provided in the output shaft housing 20 via a pair of deep groove ball bearings 43 and 44. Further, a male spline portion 16a that is spline-fitted with the female spline portion 13a of the output ring 13 is formed at the tip of the output shaft 16, and rotates integrally with the output ring 13.

  In the case of the friction type continuously variable transmission of the present invention configured as described above, the rotation of the input shaft 11 that rotates together with the drive shaft (not shown) of the electric motor is caused by the tip 11 a of the input shaft 11. It is transmitted to each roller 12 by contact between the conical surface 11 b and the pair of conical surfaces 36 a and 36 b of the intermediate roller 12. Further, the rotation of the intermediate rollers 12 is transmitted to the output ring 13 by contact between the conical surfaces 36 c of these rollers 12 and the contact portion 13 b of the inner peripheral surface of the large diameter side of the output ring 13. The output shaft 16 that is spline-coupled to the output ring 13 is rotationally driven in the direction opposite to the input shaft 11.

  When the rotational speed ratio (transmission ratio) between the input shaft 11 and the output shaft 16 is changed, and when the speed is first increased between the input shaft 11 and the output shaft 16, the speed change is performed as shown in FIG. When the motor 50 is driven, the contact portion 13b of the output ring 13 comes into contact with the large diameter side of the conical surface 36c of the recessed portion 36d of the intermediate roller 12. On the other hand, when the speed is reduced between the input shaft 11 and the output shaft 16, as shown in FIG. 4, the speed change motor 50 is driven so that the contact portion 13b of the output ring 13 is on the small diameter side of the conical surface 36c. Abut.

  Here, the contact point of the intermediate roller 12 with the input shaft 11 is positioned at both ends in the axial direction of the intermediate roller 12 so as to sandwich the contact point with the output ring 13, so that the intermediate roller 12 is stably supported without falling down. Is done. Further, the input shaft 11 and the intermediate roller 12 that are in convex and convex contact can be arranged at two points away from the contact position, and the contact surface pressure can be lowered. Further, since the intermediate roller 12 and the output ring 13 are in contact with each other with unevenness, the contact surface pressure does not become excessively high, and the contact portion 13b of the output ring 13 has a contact ellipse shape that is as small as possible so as to make point contact. Since it is formed, slip can be reduced.

Therefore, according to the friction type continuously variable transmission 10 of the present embodiment, each intermediate roller 12 includes a hollow portion 36d that is provided at the center portion in the axial direction and inscribed in the output ring 13, and both axial sides of the hollow portion 36d. Provided on the outer peripheral surface 11b of the input shaft 11 and having two conical surfaces 36a and 36b having a conical center that coincides with the conical center of the outer peripheral surface 11b of the input shaft 11, so that there is no spin loss. Since a sufficient contact length with the input shaft 11 can be obtained, the contact surface pressure with the input shaft 11 can be lowered, and the life can be extended. Further, since the intermediate roller 12 is supported at three points, the posture can be stabilized.
Further, the recess 36d is configured such that the generatrix line inscribed by the output ring 13 is parallel to the central axis of the input shaft 11, and the output ring 13 is allowed to translate while maintaining point contact with the recess 36d. The contact surface pressure with the output ring 13 is sufficiently increased, and no slip occurs.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the present embodiment, the intermediate roller as a planetary is fixed and the input shaft and the output ring as the sun member / ring member are rotated. However, the output roller is fixed and the intermediate roller revolves. Good.

FIG. 3 is a cross-sectional view taken along the line II of FIG. 2 showing the friction type continuously variable transmission according to the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 showing the friction type continuously variable transmission of the present embodiment. It is sectional drawing along the III-III line | wire of FIG. 2 of the friction type continuously variable transmission of this embodiment. It is sectional drawing which shows the state which the friction type continuously variable transmission of this embodiment performs deceleration. It is sectional drawing which shows the conventional friction type continuously variable transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Friction type continuously variable transmission 11 Input shaft 12 Intermediate roller 13 Output ring 14 Ring drive device 21 Housing 36a, 36b Conical surface 36d Recessed part

Claims (1)

A housing, an input shaft provided concentrically with respect to the housing and having a conical outer peripheral surface, and concentric with the input shaft so as to be rotatable relative to the input shaft and movable in the axial direction An output ring, a plurality of intermediate rollers that are arranged between the input shaft and the output ring and that can be brought into rolling contact with an outer peripheral surface of the input shaft and an inner peripheral surface of the output ring, and the output ring A ring drive device that moves in a direction ,
Each of the intermediate rollers is provided at a central portion in the axial direction so as to be inscribed in the output ring, and provided on both sides in the axial direction of the concave portion so as to circumscribe the outer peripheral surface of the input shaft. have a two conical surfaces having a cone center that coincides with the cone center of the outer peripheral surface, and characterized in that the contact generatrix of the recess is arranged in parallel with the central axis of said input shaft Friction type continuously variable transmission.

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