JP2013190019A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuously variable transmission in which occurrence of fluctuations in a surface pressure in a rotation transmission part can be suppressed.SOLUTION: A continuously variable transmission 1 includes a transmission shaft 60, a first rotating element 10 and a second rotating element 20, a third rotating element 30, a plurality of rolling members 50, and a transmission device 80. The plurality of rolling members 50 is arranged in such a manner that an outer diameter increases from one side to the other side with respect to a specific direction along a direction orthogonal to a first rotation axis R1. The third rotating element 30 is relatively movable in a direction intersecting the first rotation axis R1 with respect to the transmission shaft 60 and is eccentrically rotatable with respect to the first rotation axis R1, while being in contact with the plurality of rolling members 50 arranged on an outer surface 31. Thereby, the continuously variable transmission 1 has an effect of suppressing fluctuations in a surface pressure in a rotation transmission part.

Description

  The present invention relates to a continuously variable transmission.

  As a conventional transmission of a so-called traction drive system, for example, a transmission shaft serving as a rotation center, a plurality of rotational elements capable of relative rotation with a central axis of the transmission shaft as a first rotation central axis, and a first rotation central axis A continuously variable transmission of a traction planetary gear mechanism including a plurality of planetary balls as rolling members arranged radially with respect to the center is known. For example, Patent Document 1 below discloses this type of continuously variable transmission. In this continuously variable transmission, a concave groove is provided on the outer peripheral surface of a sun roller (support member) as a rotating element.

JP 2008-069979 A

  By the way, the continuously variable transmission described in Patent Document 1 as described above, for example, due to variations in the outer diameter of the planetary ball due to manufacturing errors or the like, the contact portion between the planetary ball and the input / output ring or the planetary ball and the sun roller. There may be variations in the surface pressure of the rotation transmitting portion such as the contact portion. In other words, the continuously variable transmission described in Patent Document 1 as described above requires high manufacturing accuracy when manufacturing planetary balls in order to suppress variations in the surface pressure of the rotation transmitting portion. For example, the manufacturing cost may increase.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a continuously variable transmission that can suppress variations in the surface pressure of a rotation transmission portion.

  In order to achieve the above-mentioned object, a continuously variable transmission according to the present invention is arranged such that a transmission shaft serving as a rotation center and the transmission shaft are opposed to each other in the axial direction, with a common first rotation center axis as the rotation center. A first rotating element and a second rotating element which are rotatable relative to each other; a third rotating element which is arranged on the transmission shaft so as to be rotatable relative to the transmission shaft, the first rotating element and the second rotating element; The first rotation element and the second rotation element are rotatable about a second rotation center axis different from the first rotation center axis, and are provided in a plurality radially from the first rotation center axis. A rolling member that is sandwiched between the first rotating element and the second rotating element, and a shift that is a rotation speed ratio between the rotating elements by the tilting operation of the rolling member. A transmission that can change the ratio and The plurality of rolling members are arranged such that the outer diameters increase in order from one side to the other side with respect to a specific direction along a direction orthogonal to the first rotation center axis. The rotating element is relatively movable with respect to the transmission shaft in a direction intersecting the first rotation center axis, and is in contact with the plurality of rolling members disposed on the outer surface. It is characterized by being able to rotate eccentrically with respect to the axis.

  In the continuously variable transmission, the third rotating element is formed in a cylindrical shape, the transmission shaft is inserted inside, and the inner surface of the third rotating element with respect to a direction intersecting the first rotation center axis. And a clearance between the transmission shaft and the outer surface of the transmission shaft.

  In the continuously variable transmission, the third rotation element is supported on the transmission shaft so as to be relatively rotatable, and the positioning member positions the third rotation element with respect to a direction along the first rotation center axis. Can be provided.

  In the continuously variable transmission, the third rotating element may have a groove formed in the outer surface along the rotational direction and into which a part of each of the rolling members fits.

  The continuously variable transmission according to the present invention has an effect that it is possible to suppress variation in the surface pressure of the rotation transmission portion.

FIG. 1 is a schematic cross-sectional view of a continuously variable transmission according to a first embodiment. FIG. 2 is a partial cross-sectional view of the continuously variable transmission according to the first embodiment. FIG. 3 is a perspective view of the carrier of the continuously variable transmission according to the first embodiment. FIG. 4 is a diagram illustrating an example of the outer diameter and surface pressure calculation of the planetary ball. FIG. 5 is a schematic cross-sectional view along the radial direction of the continuously variable transmission according to the first embodiment. FIG. 6 is a schematic diagram illustrating selection of the outer diameter of the planetary ball of the continuously variable transmission according to the first embodiment. FIG. 7 is a schematic sectional view of a continuously variable transmission according to the second embodiment. FIG. 8 is a partial cross-sectional view including the outer peripheral surface of the sun roller of the continuously variable transmission according to the second embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
1 is a schematic sectional view of a continuously variable transmission according to a first embodiment, FIG. 2 is a partial sectional view of the continuously variable transmission according to the first embodiment, and FIG. 3 is a sectional view of the continuously variable transmission according to the first embodiment. FIG. 4 is a diagram illustrating an example of the outer diameter and surface pressure calculation of the planetary ball, FIG. 5 is a schematic cross-sectional view along the radial direction of the continuously variable transmission according to the first embodiment, FIG. 6 is a schematic diagram illustrating selection of the outer diameter of the planetary ball of the continuously variable transmission according to the first embodiment. Note that FIG. 2 is a schematic partial cross-sectional view in which a thrust bearing and the like to be described later are omitted.

  The continuously variable transmission according to the present embodiment is mounted on a vehicle and transmits power (torque) generated by a power source such as an internal combustion engine to drive wheels of the vehicle. This continuously variable transmission is a so-called traction drive type continuously variable transmission that can transmit power between the rotating elements by a fluid such as traction oil (transmitted oil) interposed between the rotating elements in contact with each other. The continuously variable transmission uses the resistance force (traction force, shear force of the traction oil film) generated when shearing the traction oil intervening on the contact surface between one rotating element and the other rotating element to provide power (torque). To communicate. The continuously variable transmission according to the present embodiment is a so-called ball planetary continuously variable transmission (CVP: Continuously Variable Planetary).

  Specifically, as shown in FIGS. 1 and 2, the continuously variable transmission mechanism that forms the main part of the continuously variable transmission 1 of the present embodiment has a common first rotation center axis R <b> 1. A first rotating member 10 as a first rotating element capable of relative rotation, a second rotating member 20 as a second rotating element, a sun roller 30 as a third rotating element, and carriers 40 and 41 as fourth rotating elements (FIG. 2). Further, the continuously variable transmission 1 includes a planetary ball 50 as a plurality of rolling members each having a second rotation center axis R2 (see FIG. 2) different from the first rotation center axis R1, the first rotation member 10, A second rotation member 20 and a transmission shaft 60 that is the rotation center of the sun roller 30 are provided.

  Note that the continuously variable transmission 1 includes the first rotating member 10, the second rotating member 20, the sun roller 30, and the carrier 40 that are all rotatable relative to the transmission shaft 60. There is a configuration in which any one of the second rotating member 20, the sun roller 30, and the carrier 40 cannot be rotated relative to the transmission shaft 60. In the following, an example in which the carrier 41 is fixed to the transmission shaft 60 will be described, but the present invention is not limited to this. Here, the transmission shaft 60 is formed in a columnar shape with a central axis coinciding with the first rotation central axis R1, and both ends of the transmission shaft 60 are fixed to the fixed portion 2 of the continuously variable transmission 1 in a housing, a case, or a vehicle body (not shown). It is a fixed shaft that is fixed and configured not to rotate relative to the fixed portion 2. The carrier 40 and the carrier 41 are both disposed on the transmission shaft 60. The carrier 40 is supported so as to be relatively rotatable with respect to the transmission shaft 60 with the first rotation center axis R1 as the rotation center. On the other hand, the carrier 41 is fixed to the transmission shaft 60 so as to be integrally rotatable. The continuously variable transmission 1 changes the gear ratio between input and output by inclining the second rotation center axis R2 with respect to the first rotation center axis R1 and tilting the planetary ball 50.

  In the following description, unless otherwise specified, a direction along the first rotation center axis R1 or the second rotation center axis R2 is referred to as an axial direction, and a direction around the first rotation center axis R1 is referred to as a circumferential direction. Further, a direction orthogonal to the first rotation center axis R1 is referred to as a radial direction, and among these, a side facing inward is referred to as a radial inner side, and a side facing outward is referred to as a radial outer side.

  In the continuously variable transmission 1, torque is typically transmitted through the planetary balls 50 between the first rotating member 10, the second rotating member 20, the sun roller 30, and the carriers 40 and 41. For example, in the continuously variable transmission 1, one of the first rotating member 10, the second rotating member 20, the sun roller 30, and the carriers 40 and 41 serves as a torque (power) input unit, and at least of the remaining rotating elements. One is the torque output section. In the continuously variable transmission 1, the ratio of the rotation speed (the number of rotations) between any rotation element serving as an input unit and any rotation element serving as an output unit is a gear ratio. Here, the continuously variable transmission 1 will be described with respect to a case where the first rotating member 10 is an input unit and the second rotating member 20 is an output unit.

  In the continuously variable transmission 1, a plurality of planetary balls 50 are arranged radially about the center axis (first rotation center axis R <b> 1) of the transmission shaft 60. The planetary ball 50 can rotate (spin) about the second rotation center axis R2 as the rotation center. The planetary ball 50 is sandwiched between the first rotating member 10 and the second rotating member 20 that are disposed on the transmission shaft 60 so as to face the transmission shaft 60 in the axial direction. The planetary ball 50 is supported by the carriers 40 and 41 so as to be able to rotate. The continuously variable transmission 1 presses at least one of the first rotating member 10 and the second rotating member 20 against the planetary ball 50, whereby the first rotating member 10, the second rotating member 20, the sun roller 30 and the planetary ball 50. Appropriate frictional force (traction force) is generated between them and torque can be transmitted between them. The continuously variable transmission 1 tilts the planetary ball 50 on a tilt plane including the second rotation center axis R2 and the first rotation center axis R1, and the first rotation member 10 and the second rotation member 20 By changing the ratio of the rotational speed (rotational speed) between the input and output, the ratio of the rotational speed (rotational speed) between the input and output is changed.

  Hereinafter, each component of the continuously variable transmission 1 will be described in detail.

  The first rotating member 10 and the second rotating member 20 are a disk member (disk) or an annular member (ring) whose center axis coincides with the first rotation center axis R1, and the axial direction of the first rotation center axis R1 The planetary balls 50 are disposed so as to face each other. In this example, both are circular members. The first rotating member 10 and the second rotating member 20 are relatively rotatable with the common first rotation center axis R1 as the rotation center. The first rotating member 10 and the second rotating member 20 are supported by the fixed portion 2 so as to be relatively rotatable via radial bearings RB1, RB2 and the like on the outer peripheral surface side. Accordingly, the first rotating member 10 and the second rotating member 20 are positioned with respect to the radial direction of the first rotation center axis R1.

  The first rotating member 10 and the second rotating member 20 have contact surfaces 11 and 21 that contact the outer peripheral curved surface on the radially outer side of each planetary ball 50 on the inner peripheral surface. The contact surfaces 11 and 21 of the first rotating member 10 and the second rotating member 20 are, for example, a concave arc surface having a curvature equivalent to the curvature of the outer peripheral curved surface of the planetary ball 50, and a concave arc having a curvature different from the curvature of the outer peripheral curved surface. It has a shape such as a surface, a convex arc surface, or a flat surface. Here, each contact surface 11, 21 is in a state of a reference position described later (a state in which the first rotation center axis R 1 and the second rotation center axis R 2 are parallel), and the first rotation center in each planetary ball 50. The distance from the axis R1 to the contact portion with the planetary ball 50 is the same length, and the contact angles θ of the first rotating member 10 and the second rotating member 20 with respect to the planetary balls 50 are the same angle. It is trying to become.

  Here, the contact angle θ is an angle from the reference to the contact portion between the planetary ball 50 and the contact surfaces 11 and 21. Here, the radial direction is used as a reference. The contact surfaces 11 and 21 of the first rotating member 10 and the second rotating member 20 with the planetary ball 50 are in point contact or surface contact with the outer peripheral curved surface of the planetary ball 50. Further, the contact surfaces 11 and 21 of the first rotating member 10 and the second rotating member 20 with the planetary ball 50 are subjected to an axial force from the first rotating member 10 and the second rotating member 20 toward the planetary ball 50. In this case, a force (normal force Fn) is applied to the planetary ball 50 radially inward and in an oblique direction (normal force Fn).

  The continuously variable transmission 1 causes the first rotating member 10 to function as a torque input unit (input ring) when the continuously variable transmission 1 is driven forward (when torque is input to a rotating element as an input unit). The continuously variable transmission 1 causes the second rotating member 20 to function as a torque output unit (output ring) when the continuously variable transmission 1 is driven forward. In the continuously variable transmission 1, an input shaft 71 is connected to the first rotating member 10 via a torque cam 70. In the continuously variable transmission 1, the output shaft 74 is connected to the second rotating member 20 via the torque cam 73. The input shaft 71 and the output shaft 74 are supported on the outer peripheral surface of the transmission shaft 60 via a radial bearing or the like so as to be relatively rotatable about the first rotation center axis R1 as a rotation center. The input shaft 71 is connected to the power source side of the vehicle, and the output shaft 74 is connected to the drive wheel side of the vehicle.

  The torque cams 70 and 73 are torque axial force conversion mechanisms that convert rotational torque into axial force along the first rotation center axis R1. The torque cam 70 is disposed between the first rotating member 10 and the input shaft 71. The torque cam 73 is disposed between the second rotating member 20 and the output shaft 74. When the torque cam 70 transmits the rotational torque between the input shaft 71 and the first rotating member 10, each planet along the axial direction with respect to the first rotating member 10 according to the magnitude of the transmitted torque. A thrust (axial force) toward the ball 50 is generated. When the torque cam 73 transmits the rotational torque between the output shaft 74 and the second rotating member 20, each planet along the axial direction with respect to the second rotating member 20 according to the magnitude of the transmitted torque. A thrust (axial force) toward the ball 50 is generated.

  The sun roller 30 has a cylindrical shape and is disposed on the transmission shaft 60 so as to be relatively rotatable with respect to the transmission shaft 60, the first rotating member 10, the second rotating member 20, and carriers 40 and 41 described later. Further, the outer surface 31 of the sun roller 30 is in contact with the plurality of planetary balls 50. On the outer peripheral surface 31 of the sun roller 30, a plurality of planetary balls 50 are radially arranged at substantially equal intervals. Therefore, the outer surface 31 of the sun roller 30 becomes a rolling surface when the planetary ball 50 rotates. The sun roller 30 can roll (rotate) each planetary ball 50 by its own rotation, or it can rotate along with the rolling (rotational) movement of each planetary ball 50. The sun roller 30 will be described in detail later.

  As shown in FIG. 2, the carriers 40 and 41 support the ends of the support shafts 51 that support the planetary balls 50 so as not to disturb the tilting operation of the planetary balls 50. The carriers 40 and 41 are, for example, disk-shaped members whose center axes coincide with the first rotation center axis R1, and are opposed to the axial direction of the first rotation center axis R1 with the planetary ball 50 interposed therebetween. Arranged. The carriers 40 and 41 can rotate relative to the first rotating member 10, the second rotating member 20, and the sun roller 30 around the first rotation center axis R <b> 1 as the rotation center. The carriers 40 and 41 hold the end portions of the support shafts 51 in a state in which the planetary balls 50 can be tilted. As described above, the carrier 40 is supported so as to be rotatable relative to the transmission shaft 60 with the first rotation center axis R1 as the rotation center. Here, the carrier 40 is supported on the outer peripheral surface of the transmission shaft 60 via a radial bearing RB3 and the like so as to be relatively rotatable about the first rotation center axis R1. On the other hand, the carrier 41 is fixed to the transmission shaft 60 so as to be integrally rotatable. Therefore, the carrier 40 and the carrier 41 are configured to be relatively rotatable with the first rotation center axis R1 as the rotation center.

  The planetary ball 50 is a rolling member that rolls on the outer peripheral surface 31 of the sun roller 30. The planetary ball 50 is preferably a perfect sphere, but may have a spherical shape at least in the rolling direction, for example, a rugby ball having an elliptical cross section. The planetary ball 50 is rotatably supported by a support shaft 51 that passes through the center of the planetary ball 50. For example, the planetary ball 50 can be rotated relative to the support shaft 51 with the second rotation center axis R2 as the rotation axis (that is, rotation) by the radial bearings RB4 and RB5 disposed between the outer periphery of the support shaft 51. I am doing so. Therefore, the planetary ball 50 can roll on the outer peripheral surface 31 of the sun roller 30 around the support shaft 51. Both ends of the support shaft 51 protrude from the planetary ball 50 and are held by the carrier 40 and the carrier 41 in a state where the planetary ball 50 can be tilted.

  The relationship between the outer diameters and the arrangement positions of the plurality of planetary balls 50 will be described later in detail.

  The reference position of the support shaft 51 is a position where the second rotation center axis R2 is parallel to the first rotation center axis R1 (see FIG. 2). The support shaft 51 includes a reference position and a position inclined from the reference position in a tilt plane including the rotation center axis (second rotation center axis R2) and the first rotation center axis R1 formed at the reference position. Can be swung (tilted) together with the planetary ball 50. This tilt is performed with the center of the planetary ball 50 as a fulcrum in the tilt plane.

  In the continuously variable transmission 1, when the tilt angle of the planetary ball 50 is the reference position, that is, 0 degree, the first rotating member 10 and the second rotating member 20 rotate at the same rotational speed (same rotational speed). . That is, at this time, the rotation ratio (ratio of rotation speed or rotation speed) between the first rotation member 10 and the second rotation member 20 is 1, and the speed ratio γ is 1. On the other hand, when the planetary ball 50 is tilted from the reference position, the distance from the center axis of the support shaft 51 to the contact portion with the first rotating member 10 changes and the second axis from the center axis of the support shaft 51 changes. The distance to the contact portion with the rotating member 20 changes. Accordingly, either one of the first rotating member 10 and the second rotating member 20 rotates at a higher speed than when it is at the reference position, and the other rotates at a lower speed. For example, the second rotating member 20 has a lower rotation (deceleration) than the first rotating member 10 when the planetary ball 50 is tilted in one direction, and the first rotating member 10 is tilted in the other direction. (High speed). Therefore, in the continuously variable transmission 1, the rotation ratio (gear ratio γ) between the respective rotating elements such as the first rotating member 10, the second rotating member 20, and the sun roller 30 is not changed by changing the tilt angle. Can be changed in stages.

  The continuously variable transmission 1 is provided with a transmission 80 as a mechanism for changing the speed ratio γ. The transmission 80 has a gear ratio by changing the contact point between the first rotating member 10 and the planetary ball 50 and the contact point between the second rotating member 20 and the planetary ball 50 by the tilting operation of the planetary ball 50. The rotation ratio between the rotating elements is changed. Since the gear ratio γ changes with a change in the tilt angle of the planetary ball 50, the transmission 80 tilts the planetary ball 50 by inclining the second rotation center axis R2 of each planetary ball 50. Use a tilting device. The transmission 80 is in a state where the second rotation center axis R2 of each planetary ball 50 is located in a plane including the first rotation center axis R1 and is parallel to the first rotation center axis R1 in the plane, that is, a reference It is comprised so that it can be tilted to the state which exists in a position, and the state which inclines from the parallel state. As this transmission 80, one known in this technical field is used. Here, the transmission 80 is of a type that tilts the planetary ball 50 together with the support shaft 51, for example, a carrier rotation type.

  Specifically, the transmission 80 applies a force to tilt the support shaft 51 according to the relative rotation of the carrier 40 and the carrier 41, that is, tilts the planetary ball 50 together with the support shaft 51. . Here, in the continuously variable transmission 1, an offset groove 42 is formed in the carrier 40 to guide the end of the support shaft 51 in the tilting direction when each planetary ball 50 tilts. A groove 43 is formed. The offset groove portion 42 and the guide groove portion 43 are formed in positions and shapes that partially overlap each other when viewed in the axial direction of the first rotation center axis R1.

  Here, as illustrated in FIG. 3, the offset groove portion 42 is formed in an arc shape along the circumferential direction in the carrier 40. A plurality of offset groove portions 42 are provided corresponding to each support shaft 51. The plurality of offset grooves 42 are formed radially with the first rotation center axis R1 as a whole. The guide groove 43 is formed linearly along the radial direction in the carrier 41. A plurality of guide groove portions 43 are provided corresponding to each support shaft 51. In the offset groove portion 42, one end portion in the axial direction of each support shaft 51 is inserted. The guide groove portion 43 is inserted with the other axial end portion of each support shaft 51. The offset groove portion 42 is in contact with the inner wall surface and the outer peripheral surface of one end portion in the axial direction of each support shaft 51, thereby supporting one end portion in the axial direction of each support shaft 51 and positioning it at a predetermined radial position. . The offset groove portion 42 is not limited to an arc shape, and may be formed linearly in a direction inclined with respect to the radial direction orthogonal to the first rotation center axis R1. In this case, the offset groove portion 42 is formed in a linear shape, and is formed at a position offset substantially parallel to a straight line along the radial direction passing through the first rotation center axis R1.

  In the transmission 80, for example, a driving device such as a motor is driven by the control of an electronic control unit (ECU), and the generated power is transmitted to the carrier 40 via a transmission member such as a worm gear, and the carrier 40 performs the first rotation. By displacing around the central axis R <b> 1, the carrier 40 is displaced relative to the carrier 41 in the circumferential direction. As a result, the transmission 80 shifts the phase of the offset groove 42 of the carrier 40 with respect to the guide groove 43 of the carrier 41, and the radial position (support position relative to the radial direction) of one end in the axial direction of each support shaft 51. ) Is pushed up or down with respect to the radial direction. As a result, the support shaft 51 has the second rotation center axis line relative to the first rotation center axis line R1 according to the deviation between the radial position of the end portion on the one axial side and the radial position of the end portion on the other axial side. The tilt angle that is the tilt angle of R2 is changed, and the planetary ball 50 tilts accordingly. The transmission 80 can tilt the planetary ball 50 by applying the tilting force to the support shaft 51 in this manner and tilting the support shaft 51 to tilt the second rotation center axis R2.

  In the continuously variable transmission 1 configured as described above, for example, when torque is transmitted from the input shaft 71 to the first rotating member 10, the magnitude of torque transmitted by the action of the torque cam 70, the torque cam 73, and the like is increased. Accordingly, a pressing force (pressing load) is generated in a direction in which the first rotating member 10 and each planetary ball 50, the second rotating member 20 and each planetary ball 50 are relatively approached and pressed against each other. As a result, the continuously variable transmission 1 has a transmission torque capacity corresponding to the pressing force, and between the first rotating member 10 and each planetary ball 50 according to this transmission torque capacity, each planetary ball 50 and the second planetary ball 50. A traction force (friction force) is generated between the rotating member 20 and the rotating member 20. As a result, the continuously variable transmission 1 can transmit power (torque) between the first rotating member 10 and each planetary ball 50 and between each planetary ball 50 and the second rotating member 20. .

  Further, the pressing force by the torque cam 70 and the torque cam 73 is caused by the action according to the shape and positional relationship between the contact surfaces 11 and 21 of the first rotating member 10 and the second rotating member 20 and the outer surface of each planetary ball 50. It is also transmitted to the sun roller 30 via the ball 50. Accordingly, the continuously variable transmission 1 generates a traction force (friction force) between each planetary ball 50 and the sun roller 30 according to the pressing force by the torque cam 70 and the torque cam 73, and each planetary ball 50 and the sun roller 30. Can transmit power (torque) to each other.

  Therefore, the continuously variable transmission 1 generates a frictional force (traction force) between the first rotating member 10 and each planetary ball 50 as the first rotating member 10 rotates, and each planetary ball 50 starts to rotate. . The continuously variable transmission 1 generates a frictional force between each planetary ball 50 and the second rotating member 20 and between each planetary ball 50 and the sun roller 30 due to the rotation of each planetary ball 50. The two-rotating member 20 and the sun roller 30 also start to rotate. Similarly, in the continuously variable transmission 1, each planetary ball 50 starts rotating as the second rotating member 20 rotates, and the first rotating member 10 and the sun roller 30 also start rotating. The continuously variable transmission 1 can change the speed ratio γ steplessly by the transmission 80 tilting each planetary ball 50 and changing the tilt angle of each planetary ball 50 as described above. it can.

  By the way, in the continuously variable transmission 1 of the present embodiment, there is a possibility that the surface pressure of the rotation transmitting portion may vary due to, for example, variations in the outer diameter of the planetary ball 50 due to manufacturing errors or the like. Here, the rotation transmission portion in the continuously variable transmission 1 typically includes a contact portion between the first rotating member 10 and each planetary ball 50, a contact portion between the second rotating member 20 and each planetary ball 50, A contact portion between the sun roller 30 and each planetary ball 50 or the like.

  FIG. 4 illustrates an example of the outer diameter and surface pressure calculation of the planetary ball 50. In this case, the surface pressure of the error planetary ball 50 having a relatively small diameter relative to the surface pressure of the ideal planetary ball 50 is relatively small, and the outer diameter of the error planetary ball 50 having a small diameter with respect to the ideal planetary ball 50 is not the same. If it exceeds a predetermined value, the contact point between the error planetary ball 50 and the first rotating member 10, the second rotating member 20, etc. is not formed. Then, as the surface pressure that the error planetary ball 50 takes on is reduced, the surface pressure of the ideal planetary ball 50 may be relatively higher than the ideal surface pressure when there is no variation.

  In order to eliminate such variations in surface pressure, the continuously variable transmission 1 of the present embodiment arranges a plurality of planetary balls 50 having different outer diameters due to manufacturing errors and the like in a predetermined order, and the sun roller 30 is disposed on the transmission shaft. A structure that can float in the radial direction with respect to 60 and be eccentric. Thereby, the continuously variable transmission 1 arrange | positions the several planetary ball 50 from which an outer diameter differs so that it may contact the 1st rotation member 10, the 2nd rotation member 20, and the sun roller 30 appropriately, for example, a manufacturing error etc. Thus, even when the outer diameter of the planetary ball 50 varies, the variation in the surface pressure of the rotation transmitting portion is suppressed.

  Specifically, as shown in FIG. 5, the plurality of planetary balls 50 have larger outer diameters in order from one side to the other side with respect to a specific direction along the direction orthogonal to the first rotation center axis R1. It is arranged to become. Here, the specific direction is any one of the radial directions orthogonal to the first rotation center axis R1.

  Here, as shown in FIG. 5, an example of selection and arrangement of the outer diameter of the planetary balls 50 will be described by taking a case where the continuously variable transmission 1 includes six planetary balls 50 as an example.

  The continuously variable transmission 1 illustrated in FIG. 5 includes planetary balls 50a, 50b, 50c, 50d, 50e, and 50f as six planetary balls 50. The planetary balls 50a, 50b, 50c, 50d, 50e, 50f are provided radially around the first rotation center axis R1 and are arranged at equal intervals around the first rotation center axis R1. Here, the continuously variable transmission 1 includes a planetary ball 50a, a planetary ball 50b, a planetary ball 50c, a planetary ball 50d, a planetary ball 50e, and a planetary ball 50f in the clockwise direction around the first rotation center axis R1 in FIG. It is arranged in the order. In the continuously variable transmission 1, the planetary ball 50a and the planetary ball 50d are positioned point-symmetrically with respect to the radial direction about the first rotation center axis R1, and the planetary ball 50b and the planetary ball 50e are opposed to each other. The planetary ball 50c and the planetary ball 50f face each other and are point-symmetrically positioned.

  Here, the planetary balls 50a, 50b, 50c, 50d, 50e, and 50f are the first set in which the planetary ball 50a and the planetary ball 50f are located on one side in a specific direction, and the planetary ball 50b and the planetary ball 50e are specified. A second set is located in the center of the direction, a planetary ball 50c and a planetary ball 50d are distinguished into a third set located on the other side in the specific direction. The planetary balls 50a, 50b, 50c, 50d, 50e, and 50f are a first set of the planetary ball 50a and the planetary ball 50f, the planetary ball 50b and the planetary ball 50e with respect to a specific direction orthogonal to the first rotation center axis R1. And the second set, and the third set of planetary balls 50c and 50d are selected in order of the outer diameter. A predetermined manufacturing error is allowed for the outer diameter of the planetary ball 50 in each of the above groups.

  Regarding the selection of the outer diameter of each set of planetary balls 50, first, the plurality of planetary balls 50 before assembly are classified into a plurality of ranks according to the manufacturing accuracy of the outer diameter, and then the planetary balls in the same set are used. 50 is selected from the planetary balls 50 in the same rank. For example, as schematically shown in FIG. 6, the plurality of planetary balls 50 before assembling are classified into five ranks of rank 0, rank +1, rank +2, rank −1, and rank −2 according to the manufacturing error of the outer diameter. Are distinguished. In FIG. 6, the vertical axis represents the outer diameter [mm] of the planetary ball 50, and when the allowable manufacturing error of the plurality of planetary balls 50 as a whole is T2, the allowable manufacturing of the outer diameter within each rank. The error is assumed to be a tolerance value T0 that is smaller than T2. Here, the outer diameter of the planetary ball 50 increases in the order of rank +1 and rank +2 with respect to rank 0, and decreases in the order of rank -1 and rank -2.

  The first set of planetary balls 50a and 50f is selected from the same rank on the minus side. The second set of the planetary ball 50b and the planetary ball 50e is selected from rank 0, respectively. The third set of planetary balls 50c and 50d is a positive rank, and is selected from the same rank that is symmetrical with the first set with rank 0 as a reference. That is, as shown in selection example 1 in FIG. 6, the first set of planetary balls 50a and 50f is selected from within rank-1, and the second set of planetary balls 50b and 50e is The third set of planetary balls 50c and 50d is selected from within rank +1, respectively. Alternatively, as shown in selection example 2 in FIG. 6, the first set of planetary balls 50a and 50f is selected from within rank-2, and the second set of planetary balls 50b and 50e is The third set of planetary balls 50c and 50d is selected from within rank +2, respectively.

  Thus, as illustrated in FIGS. 1 and 5, the plurality of planetary balls 50 have larger outer diameters in order from one side to the other side with respect to a specific direction orthogonal to the first rotation center axis R1. It is selected and arranged as follows. That is, the plurality of planetary balls 50 are in the order of a first set of planetary balls 50a and 50f, a second set of planetary balls 50b and 50e, and a third set of planetary balls 50c and 50d. Selection and arrangement are made so that the outer diameter becomes larger.

  The continuously variable transmission 1 of the present embodiment is arranged in a predetermined order by adopting a structure in which the sun roller 30 floats so as to be eccentric with respect to the transmission shaft 60, as shown in FIGS. Further, the planetary balls 50 having different outer diameters can appropriately contact the outer peripheral surface 31 of the sun roller 30.

  The sun roller 30 is movable relative to the transmission shaft 60 in the radial direction intersecting the first rotation center axis R1. Here, as described above, the sun roller 30 is formed in a cylindrical shape (cylindrical shape), and the transmission shaft 60 is inserted inside. The sun roller 30 has a clearance C (see FIG. 5) between the inner peripheral surface of the sun roller 30 and the outer peripheral surface of the transmission shaft 60 with respect to the radial direction intersecting the first rotation center axis R1.

  As a result, the sun roller 30 can be moved relative to the radial direction as described above, and can have a float structure with respect to the transmission shaft 60. As a result, the sun roller 30 rotates eccentrically with respect to the first rotation center axis R1 while in contact with a plurality of planetary balls 50 having different outer diameters arranged on the outer peripheral surface (outer surface) 31 in a predetermined order. Is possible. Here, the sun roller 30 is parallel to the first rotation center axis R1 and is eccentric by an eccentric amount D (see FIGS. 1, 5, and 6) with respect to the first rotation center axis R1. The axis R3 can be rotated as the center of rotation. Here, the eccentric amount D is typically an amount corresponding to the difference in the outer diameters of the plurality of planetary balls 50.

  The continuously variable transmission 1 includes thrust bearings RB6 and RB7 as positioning members, and the sun roller 30 is rotatably supported by the thrust bearings RB6 and RB7. The thrust bearings RB6 and RB7 support the sun roller 30 so as to be rotatable relative to the transmission shaft 60, and position the sun roller 30 in the axial direction along the first rotation center axis R1.

  The thrust bearing RB6 is formed between one end portion of the sun roller 30 (here, the end portion on the first rotating member 10 side) and the annular portion 61 of the transmission shaft 60 with respect to the axial direction of the first rotation center axis R1. The one end portion of the sun roller 30 is rotatably supported by the annular portion 61 of the transmission shaft 60. The annular portion 61 is formed in an annular shape integrally with the transmission shaft 60 on the outer peripheral surface of the transmission shaft 60. The thrust bearing RB7 has an annular shape assembled to the other end of the sun roller 30 (here, the end on the second rotating member 20 side) and the transmission shaft 60 with respect to the axial direction of the first rotation center axis R1. It is interposed between the member 62 and one end of the sun roller 30 is rotatably supported by the annular member 62. The annular member 62 is formed in an annular shape, and is positioned and assembled in the axial direction on the outer peripheral surface of the transmission shaft 60 via a snap ring 63 or the like. The sun roller 30 is assembled between the annular portion 61 and the annular member 62 with respect to the axial direction via thrust bearings RB6 and RB7. Therefore, the sun roller 30 is supported by the thrust bearings RB6 and RB7 so as to be relatively rotatable with respect to the transmission shaft 60 and positioned in the axial direction. The continuously variable transmission 1 may include a sliding washer or the like instead of the thrust bearings RB6 and RB7 as a positioning member.

  When the continuously variable transmission 1 configured as described above rotates around the first rotation center axis R <b> 1 with the first rotating member 10 and the second rotating member 20 in contact with the planetary balls 50, the sun roller 30. Rotates around the third rotation center axis R3 eccentric with respect to the first rotation center axis R1 while in contact with each planetary ball 50. That is, the sun roller 30 is arranged in such a manner that a plurality of planetary balls 50 are arranged so that the outer diameter sequentially increases along a specific direction and is fixedly supported so as not to revolve with respect to the transmission shaft 60. As shown in the figure, the third rotation center axis R3 rotates with respect to the first rotation center axis R1 in a state of being eccentric to the first set side of the plurality of planetary balls 50, that is, the planetary balls 50a and 50f. As a result, the continuously variable transmission 1 is configured such that the sun roller 30 is eccentric and rotatable with respect to the rotation center of the first rotating member 10 and the second rotating member 20, so that the outer diameters arranged in a predetermined order are arranged. The first rotating member 10, the second rotating member 20, and the sun roller 30 can be in contact with each other with a plurality of different planetary balls 50 in appropriate contact states.

  Accordingly, the continuously variable transmission 1 is configured such that the sun roller 30 rotates eccentrically with respect to the plurality of planetary balls 50 arranged so that the outer diameter sequentially increases along the specific direction, so that each planetary ball 50 and the contact surface are in contact with each other. 11, 21 and the surface pressure of the rotation transmission portion with the outer peripheral surface 31 are made uniform, and the occurrence of variations is suppressed. As a result, the continuously variable transmission 1 transmits rotation of the contact portion between the planetary ball 50 and the first rotating member 10, the second rotating member 20, the sun roller 30, etc., even if the production accuracy of the planetary ball 50 is lowered. It is possible to suppress the occurrence of variation in the surface pressure of the portion, and the surface pressure can be easily equalized. As a result, the continuously variable transmission 1 can, for example, reduce manufacturing costs, improve power transmission efficiency, and improve surface durability of the high surface pressure portion in the rotation transmission portion. Can do.

  Then, the continuously variable transmission 1 does not decenter the sun roller 30, for example, instead of rotating the first rotating member 10 and the second rotating member 20 with the rotation center axis relative to the first rotation center axis R1. While allowing a fixed part that is immovable, a movable part whose rotation center axis is swingable with respect to the first rotation center axis R1, and contacting each planetary ball 50, and allowing the inclination of the movable part with respect to the fixed part, Loss of transmission torque that occurs between the fixed part and the movable part, for example, compared to a case that includes a transmission part that can transmit torque between the fixed part and the movable part. Can be prevented from occurring. That is, since the continuously variable transmission 1 has a configuration in which the sun roller 30 is eccentric, for example, the above-described movable part is inclined with respect to the fixed part, and thus occurs between the movable part and the fixed part. There is no slippage of the rocking motion. As a result, the continuously variable transmission 1 is accompanied by, for example, swinging between the movable portion and the fixed portion as described above when the first rotating member 10, the second rotating member 20, the sun roller 30, and the like rotate. Thus, friction loss does not occur, and therefore the power transmission efficiency can be improved as compared with the above case.

  The continuously variable transmission 1 according to the embodiment described above includes the transmission shaft 60, the first rotating member 10 and the second rotating member 20, the sun roller 30, the planetary ball 50, and the transmission 80. . The transmission shaft 60 is the center of rotation. The first rotating member 10 and the second rotating member 20 are disposed so as to face the transmission shaft 60 in the axial direction, and can be relatively rotated about the common first rotation center axis R1. The sun roller 30 is disposed on the transmission shaft 60 so as to be rotatable relative to the first rotating member 10 and the second rotating member 20. The planetary balls 50 are rotatable about a second rotation center axis R2 different from the first rotation center axis R1, and a plurality of planetary balls 50 are provided radially about the first rotation center axis R1. It is sandwiched between the second rotating member 20 and torque can be transmitted between the first rotating member 10 and the second rotating member 20. The transmission 80 can change the speed ratio, which is the rotational speed ratio between the first rotating member 10 and the second rotating member 20, by the tilting operation of the planetary ball 50. The plurality of planetary balls 50 are arranged such that the outer diameters increase in order from one side to the other side with respect to a specific direction along the direction orthogonal to the first rotation center axis R1. The sun roller 30 is relatively movable with respect to the transmission shaft 60 in a direction intersecting the first rotation center axis R1 and is in contact with the plurality of planetary balls 50 disposed on the outer peripheral surface 31. It can be eccentrically rotated with respect to the axis R1.

  Therefore, in the continuously variable transmission 1, the plurality of planetary balls 50 are arranged so that their outer diameters increase in order along the specific direction, and the sun roller 30 is eccentric with respect to the transmission shaft 60 and the first rotation center axis R1. Since it is a structure, it can suppress that the surface pressure of a rotation transmission part generate | occur | produces, for example, after suppressing manufacturing cost. Further, the continuously variable transmission 1 can improve power transmission efficiency as described above. Further, the continuously variable transmission 1 does not need to be provided with a radial bearing or the like between the sun roller 30 and the transmission shaft 60 in the radial direction orthogonal to the first rotation center axis R1, for example. Can be suppressed.

[Embodiment 2]
7 is a schematic cross-sectional view of a continuously variable transmission according to the second embodiment. FIG. 8 is a partial cross-sectional view including the outer peripheral surface of the sun roller of the continuously variable transmission according to the second embodiment (indicated by a dotted dotted line A in FIG. 7). Part). The continuously variable transmission according to the second embodiment is different from the first embodiment in that the sun roller has a groove. In addition, about the structure, operation | movement, and effect which are common in embodiment mentioned above, the overlapping description is abbreviate | omitted as much as possible.

  In the continuously variable transmission 201 according to the present embodiment, the sun roller 30 has a guide groove (groove) 232 as shown in FIGS. The guide groove 232 is formed on the outer peripheral surface 31 of the sun roller 30 along the rotation direction. That is, the guide groove 232 is formed in an annular shape over the entire circumference along the circumferential direction of the outer peripheral surface 31. The guide groove 232 has, for example, an arc shape or a substantially V-shaped cross section along the third rotation center axis R3. The guide groove 232 is formed at a contact portion between each planetary ball 50 and the outer peripheral surface 31. In the guide groove 232, a part of each planetary ball 50 is fitted and the outer peripheral surface of each planetary ball 50 comes into contact with the bottom surface. In other words, a part of each planetary ball 50 is accommodated inside the guide groove 232. In this case, each planetary ball 50 typically makes point contact with the bottom surface of the guide groove 232 of the sun roller 30 at at least two points. The sun roller 30 and each planetary ball 50 rotate around the third rotation center axis R3 and the second rotation center axis R2 with the bottom surface of the guide groove 232 and the planetary ball 50 in contact with the outer peripheral surface. Can do. As a result, the continuously variable transmission 201 reduces, for example, the contact surface pressure per point as compared with a case where the outer peripheral surface of each planetary ball 50 and the outer peripheral surface 31 of the sun roller 30 are in contact at one point. Therefore, the durability of the sun roller 30 and each planetary ball 50 can be improved.

  Since the continuously variable transmission 201 of the present embodiment is configured such that the sun roller 30 and each planetary ball 50 rotate with a part of each planetary ball 50 fitted in the guide groove 232 as described above. The planetary ball 50 itself also functions as a positioning member for the sun roller 30. That is, the sun roller 30 rotates in a state in which a part of each planetary ball 50 sandwiched and positioned by the first rotating member 10 and the second rotating member 20 is fitted in the guide groove 232, so that the first rotating member 10. Guided to the position of each planetary ball 50 along the position of the second rotating member 20.

  Therefore, the sun roller 30 is positioned with respect to the axial direction along the first rotation center axis R <b> 1 by each planetary ball 50. As a result, the continuously variable transmission 201 does not include the thrust bearings RB6 and RB7, the annular portion 61, the annular member 62, the snap ring 63, and the like shown in FIG. Positioning can be performed with respect to the axial direction along the axis R1. In the transmission shaft 60 of the present embodiment, the end portion on the second rotating member 20 side is fixed to the fixed portion 2, while the end portion on the first rotating member 10 side is a free end.

  In the continuously variable transmission 201 according to the embodiment described above, the plurality of planetary balls 50 are arranged so that the outer diameters are increased in order along a specific direction, and the sun roller 30 is the transmission shaft 60 and the first rotation center axis. Since the configuration is eccentric with respect to R1, for example, it is possible to suppress the occurrence of variations in the surface pressure of the rotation transmission portion while suppressing the manufacturing cost.

  Furthermore, according to the continuously variable transmission 201 according to the embodiment described above, the sun roller 30 has the guide groove 232 that is formed on the outer peripheral surface 31 along the rotation direction and into which a part of each planetary ball 50 is fitted. Therefore, the continuously variable transmission 201 can position the sun roller 30 with respect to the axial direction along the first rotation center axis R1 by each planetary ball 50, so that the number of components can be reduced. Thereby, the continuously variable transmission 201 can reduce the size of the device and further reduce the manufacturing cost.

  The continuously variable transmission according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims.

1,201 continuously variable transmission 10 first rotating member (first rotating element)
20 Second rotating member (second rotating element)
30 Sun Roller (third rotating element)
31 Outer peripheral surface (outer surface)
40, 41 Carrier 42 Offset groove 43 Guide groove 50, 50a, 50b, 50c, 50d, 50e, 50f Planetary ball (rolling member)
51 Support shaft 60 Transmission shaft 61 Annular portion 62 Annular member 63 Snap ring 80 Transmission device 232 Guide groove (groove)
C Clearance R1 1st rotation center axis R2 2nd rotation center axis R3 3rd rotation center axis RB6, RB7 Thrust bearing (positioning member)

Claims (4)

A transmission shaft as a center of rotation;
A first rotation element and a second rotation element that are arranged opposite to the transmission shaft in the axial direction and are capable of relative rotation about a common first rotation center axis;
A third rotating element disposed on the transmission shaft so as to be rotatable relative to the transmission shaft, the first rotating element, and the second rotating element;
The second rotation center axis that is different from the first rotation center axis is rotatable about a rotation center, and a plurality of radial rotations are provided around the first rotation center axis, and the first rotation element and the second rotation element A rolling member that is sandwiched between and capable of transmitting torque between the first rotating element and the second rotating element;
A transmission capable of changing a transmission gear ratio, which is a rotation speed ratio between the rotating elements, by a tilting operation of the rolling member;
The plurality of rolling members are arranged such that an outer diameter increases in order from one side to the other side with respect to a specific direction along a direction orthogonal to the first rotation center axis.
The third rotation element is movable relative to the transmission shaft in a direction intersecting the first rotation center axis, and is in contact with the plurality of rolling members disposed on an outer surface. It is characterized by being able to rotate eccentrically with respect to one rotation center axis.
Continuously variable transmission. The third rotation element is formed in a cylindrical shape, the transmission shaft is inserted inside, and the third rotation element is disposed between the inner surface of the third rotation element and the outer surface of the transmission shaft with respect to a direction intersecting the first rotation center axis. Having clearance,
The continuously variable transmission according to claim 1. A positioning member for supporting the third rotating element on the transmission shaft so as to be relatively rotatable, and positioning the third rotating element with respect to a direction along the first rotation center axis;
The continuously variable transmission according to claim 1 or 2. The third rotating element has a groove formed in the outer surface along the rotation direction and into which a part of each rolling member is fitted.
The continuously variable transmission according to claim 1 or 2.

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