JP2012127457A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel efficiency when a transmission gear ratio is on a side where speed is increased to a maximum level.SOLUTION: In a continuously variable transmission which has a first rotating member 10, a second rotating member 20, and a sun roller 30 on a shaft 50 having a first rotational center axis R1, a plurality of planet balls 40 which are put between the first and second rotating members 10 and 20 and which are arranged in a radial fashion, a carrier 60 fixed to the shaft 50, and a transmission which has an iris plate 81 which enables an inclined rotating operation of the planet balls 40, the carrier 60 has guide grooves 63 and 64 which guide a projecting portion from the planet balls 40 of a support shaft 41 in a radial direction, and the iris plate 81 has a squeezing hole 82 that moves away in a circumferential direction with respect to a reference line of the radial direction as it moves toward an outer end of the radial direction. The squeezing hole 82 is a portion formed in an arc shape of a concentric circle which centers on the first rotational center axis R1, and has an arc portion 82a which can hold the projecting portion at one side of the support shaft 41 when a transmission gear ratio is on a side where speed is increased to a maximum level.

Description

  The present invention includes a plurality of rotating elements having a common rotating shaft, and a plurality of rolling members arranged radially with respect to the rotating shaft, and each rolling element sandwiched between two of the rotating elements. The present invention relates to a continuously variable transmission that continuously changes a gear ratio between input and output by tilting a member.

  Conventionally, as this type of continuously variable transmission, a transmission shaft serving as a rotation center, a plurality of rotational elements capable of relative rotation with the central axis of the transmission shaft as a first rotation central axis, and the first rotation central shaft And a plurality of rolling members radially arranged around the first rotation center axis, the first rotation element and the second rotation element disposed opposite to each other. So-called traction planetary gears, in which each rolling member is sandwiched between the outer peripheral surface of the third rotating element and the gear ratio is steplessly changed by tilting the rolling member. One with a mechanism is known. The continuously variable transmission includes a support shaft (rotary shaft) that rotates and supports the rolling member, and a fixed element that holds the rolling member via respective protruding portions of the support shaft from the rolling member. Are prepared for each rolling member. Each disk member constituting the fixing element is formed with a guide groove or a guide hole for holding each projecting portion of the support shaft and guiding in the radial direction when the rolling member is tilted. For example, Patent Documents 1 and 2 below disclose this type of continuously variable transmission. These continuously variable transmissions of Patent Documents 1 and 2 include an iris plate (disk member) for tilting the rolling member. The iris plate is provided with an iris groove into which the end of the support shaft is inserted. In the iris groove, the end of the support shaft is rotated at its own speed so that the end of the support shaft has the maximum speed reduction ratio and the maximum speed increase. Guidance is made between the maximum speed increasing portion at which the gear ratio becomes. Note that the iris groove of Patent Document 1 has an arcuate portion concentric with the transmission shaft further extended from the most decelerating portion (that is, an arcuate portion along the circumferential direction), and the iris plate is in the state of the most decelerating state. It can be further rotated. The arc-shaped portion is provided on the inside of the iris plate in the radial direction. In the continuously variable transmission of this Patent Document 1, by further rotating the iris plate from the most decelerated state, the clutch is pressed to the thrust bearing side by the ramp provided on the outer peripheral side of the iris plate, and from the input side Is interrupted. That is, the arcuate portion of the iris groove of Patent Document 1 is for interrupting power transmission while maintaining the speed ratio at the maximum deceleration state. Further, in the continuously variable transmission of Patent Document 2, when the first rotating element and the second rotating element are the input side and the output side, respectively, the first rotating element and the disk member on the input side of the fixed element An iris plate is disposed between them.

US Patent Application Publication No. 2009/0082169 Japanese Utility Model Publication No. 52-35481

  By the way, when the iris plate as described above is used for the tilting mechanism (transmission mechanism) of the rolling member, a radial force is applied from the support shaft to the groove wall of the iris groove. Try to rotate the iris plate. For this reason, when holding at a certain speed ratio, for example, it is necessary to continuously apply a force for stopping the rotation of the iris plate. Therefore, in this continuously variable transmission, energy for generating the force is required to maintain the gear ratio, which may lead to deterioration in fuel consumption. This is the same when the gear ratio is the maximum speed increase or the maximum speed reduction.

  Therefore, an object of the present invention is to provide a continuously variable transmission that can improve the inconvenience of the conventional example and improve the fuel efficiency.

  In order to achieve the above-described object, the present invention provides a first and a first relatively rotatable shaft having a transmission shaft as a fixed shaft serving as a rotation center and a common first rotation center shaft arranged opposite to each other on the transmission shaft. 2 rotation elements and a second rotation center axis parallel to the first rotation center axis, and a plurality of the rotation elements arranged radially about the first rotation center axis are arranged in the first and second rotation elements. A rolling member sandwiched between the rolling member and the second rotation center axis, the supporting shaft of the rolling member projecting at both ends from the rolling member, and the respective rolling members are disposed on the outer peripheral surface; A third rotating element capable of relative rotation with respect to the transmission shaft and the first and second rotating elements; a guide groove fixed to the transmission shaft and guiding each protrusion of the support shaft in a radial direction; Alternatively, the first element is fixed to the fixed element having the guide hole and the transmission shaft. A tilting element that enables tilting operation of each rolling member by relatively rotating around a central axis is provided, and each contact point between the first rotating element and each rolling member and the second The first rotating element on the input side and the second rotating element on the output side that become a gear ratio are obtained by changing the respective contact points between the rotating element and each rolling member by the tilting operation of each rolling member. A hole or a groove that moves away from the radial reference line in the circumferential direction toward the outer side in the radial direction, and one of the inserted support shafts The rolling member moves toward one end so that the rolling member tilts toward the speed increasing side, and the protruding member moves toward the other end to move the rolling member. In a continuously variable transmission in which a throttle hole or throttle groove that tilts toward the deceleration side is formed in the tilt element. The throttle hole or the throttle groove is a portion formed in a concentric circular arc shape with the first rotation center axis as a center, and one protruding portion of the support shaft when the speed ratio is the maximum speed increase. It has the circular arc part which can hold | maintain.

  Here, the throttle hole or the throttle groove is formed in a concentric circular arc shape with the first rotation center axis as the center, and can hold one protrusion of the support shaft when the speed ratio is the maximum speed reduction. It is desirable to further have a circular arc portion.

  Moreover, it is desirable that the tilting element is disposed on the output side of the second rotating element with respect to the rolling members.

  According to the continuously variable transmission according to the present invention, when the speed ratio is the maximum speed increase, the force acting on the tilting element from the support shaft is only the tilting force in the radial direction, and the force rotates to the tilting element. No moment is generated. Therefore, in this continuously variable transmission, the rotational moment for canceling the rotational moment, that is, the transmission ratio maintaining moment for keeping the transmission ratio at the maximum speed, need not be applied to the tilting element. No power is required to generate the gear ratio maintaining moment. Therefore, this continuously variable transmission can improve the fuel consumption of the vehicle when the gear ratio is at the maximum speed.

FIG. 1 is a partial cross-sectional view showing a configuration of a first embodiment of a continuously variable transmission according to the present invention. FIG. 2 is a diagram for explaining the guide groove of the carrier. FIG. 3 is a diagram illustrating the iris plate. FIG. 4 is a diagram for explaining the shift of the support shaft during deceleration. FIG. 5 is a diagram for explaining the side slip speed during deceleration that occurs between the planetary ball and the sun roller. FIG. 6 is a diagram for explaining the tilting operation during deceleration. FIG. 7 is a diagram for explaining the component force of the tangential force of the output side contact portion during deceleration. FIG. 8 is a diagram for explaining the force acting on the iris plate from the support shaft during deceleration. FIG. 9 is a view for explaining the positional relationship among the iris plate aperture, the carrier guide groove, and the support shaft. FIG. 10 is a diagram for explaining the shift of the support shaft during acceleration. FIG. 11 is a diagram for explaining the side slip speed at the time of acceleration generated between the planetary ball and the sun roller. FIG. 12 is a diagram for explaining the tilting operation at the time of acceleration. FIG. 13 is a diagram for explaining the component force of the tangential force of the output side contact portion at the time of acceleration. FIG. 14 is a diagram for explaining the force acting on the iris plate from the support shaft at the time of acceleration. FIG. 15 is a diagram illustrating the positional relationship between the iris hole of the iris plate and the support shaft when the speed ratio is the maximum speed increase.

  Embodiments of a continuously variable transmission according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

[Example]
An embodiment of a continuously variable transmission according to the present invention will be described with reference to FIGS.

  First, an example of a continuously variable transmission according to the present embodiment will be described with reference to FIG. Reference numeral 1 in FIG. 1 indicates a continuously variable transmission according to this embodiment.

  The continuously variable transmission mechanism that forms the main part of the continuously variable transmission 1 includes first to third rotating elements 10, 20, 30 that are capable of relative rotation with each other and have a common first rotation center axis R 1. A plurality of rolling members 40 each having a second rotation center axis R2 parallel to the first rotation center axis R1 and a reference position to be described later, and rotations of the first to third rotation elements 10, 20, 30 This is a so-called traction planetary gear mechanism having a shaft 50 as a transmission shaft arranged in the center and a fixing element fixed to the shaft 50 and holding each rolling member 40 in a tiltable manner. . The continuously variable transmission 1 changes the speed ratio γ between input and output by inclining the second rotation center axis R2 with respect to the first rotation center axis R1 and tilting the rolling member 40. . In the following, unless otherwise specified, the direction along the first rotation center axis R1 and the second rotation center axis R2 is referred to as the axial direction, and the direction around the first rotation center axis R1 is referred to as the circumferential direction. Further, the direction orthogonal to the first rotation center axis R1 is referred to as a radial direction, and among these, the inward side is referred to as a radial inner side, and the outward side is referred to as a radial outer side.

  In the continuously variable transmission 1, torque is transmitted through the rolling members 40 among the first rotating element 10, the second rotating element 20, and the third rotating element 30. For example, in the continuously variable transmission 1, one of the first to third rotating elements 10, 20, 30 is an input part of torque (power), and at least one of the remaining rotating elements is torque. Output section. For this reason, in this continuously variable transmission 1, the ratio of the rotational speed (the number of rotations) between any rotation element serving as an input unit and any rotation element serving as an output unit is the gear ratio γ. For example, the continuously variable transmission 1 is disposed on the power transmission path of the vehicle. In that case, the input part is connected with the power source side, such as an engine and a motor, and the output part is connected with the drive wheel side. In this continuously variable transmission 1, the rotation operation of each rotation element when torque is input to the rotation element as the input unit is referred to as normal drive, and the rotation element as the output unit is in the direction opposite to that during normal drive. The rotating operation of each rotating element when torque is input is called reverse driving. For example, in the continuously variable transmission 1, according to the example of the preceding vehicle, when the torque is input from the power source side to the rotating element as the input unit and the rotating element is rotated as in acceleration or the like, Driving is performed, and reverse driving is performed when torque in the opposite direction to that during forward driving is input to the rotating rotating element serving as the output unit from the driving wheel side, such as deceleration.

  In the continuously variable transmission 1, a plurality of rolling members 40 are arranged radially about the central axis (first rotation central axis R <b> 1) of the shaft 50. The respective rolling members 40 are sandwiched between the first rotating element 10 and the second rotating element 20 that are arranged to face each other, and are disposed on the outer peripheral surface of the third rotating element 30. Further, each rolling member 40 rotates around its own rotation center axis (second rotation center axis R2). The continuously variable transmission 1 is configured to roll with the first to third rotating elements 10, 20, 30 by pressing at least one of the first and second rotating elements 10, 20 against the rolling member 40. An appropriate tangential force (traction force) is generated between the member 40 and torque can be transmitted therebetween. Further, the continuously variable transmission 1 tilts each rolling member 40 on a tilt plane including its second rotation center axis R2 and first rotation center axis R1, and the first rotation element 10 By changing the ratio of the rotation speed (rotation speed) between the second rotation element 20 and the second rotation element 20, the ratio of the rotation speed (rotation speed) between the input and output is changed.

  Here, in the continuously variable transmission 1, the first and second rotating elements 10 and 20 function as a ring gear as a planetary gear mechanism. Further, the third rotating element 30 functions as a sun roller of the traction planetary gear mechanism. The rolling member 40 functions as a ball-type pinion in the traction planetary gear mechanism, and the fixing element 60 functions as a carrier. Hereinafter, the first and second rotating elements 10 and 20 are referred to as “first and second rotating members 10 and 20”, respectively. The third rotating element 30 is referred to as “sun roller 30”, and the rolling member 40 is referred to as “planetary ball 40”. The fixing element 60 is referred to as a “carrier 60”.

  Further, the shaft 50 is fixed to a fixed portion of the continuously variable transmission 1 in a housing or a vehicle body (not shown), and is a columnar fixed shaft configured not to rotate relative to the fixed portion.

  The first and second rotating members 10 and 20 are disk members (disks) or ring members (rings) whose center axes coincide with the first rotation center axis R1, and each planetary ball is opposed in the axial direction. 40 is interposed. In this example, both are circular members.

  Each of the first and second rotating members 10 and 20 has a contact surface that comes into contact with an outer peripheral curved surface on the radially outer side of each planetary ball 40 described in detail later. Each contact surface has, for example, a concave arc surface having a curvature equivalent to the curvature of the outer peripheral curved surface of the planetary ball 40, a concave arc surface having a curvature different from the curvature of the outer peripheral curved surface, a convex arc surface, or a flat surface. is doing. Here, the first and second contact surfaces are formed so that the distance from the first rotation center axis R1 to the contact portion with each planetary ball 40 becomes the same length in the state of a reference position described later. The contact angles θ of the rotating members 10 and 20 with respect to the planetary balls 40 are the same. The contact angle θ is an angle from the reference to the contact portion with each planetary ball 40. Here, the radial direction is used as a reference. The respective contact surfaces are in point contact or surface contact with the outer peripheral curved surface of the planetary ball 40. Each contact surface is radially inward and oblique to the planetary ball 40 when an axial force is applied from the first and second rotating members 10, 20 toward the planetary ball 40. The force (normal force) is applied.

  In this example, the first rotating member 10 acts as a torque input portion when the continuously variable transmission 1 is positively driven, and the second rotating member 20 acts as a torque output portion when the continuously variable transmission 1 is positively driven. . Accordingly, the input shaft 11 is connected to the first rotating member 10, and the output shaft 21 is connected to the second rotating member 20.

  The output shaft 21 includes a disk portion 21a and a cylindrical portion 21b having a center axis coinciding with the first rotation center axis R1. The cylindrical portion 21b is provided on the inner peripheral side of the disk portion 21a, and the inner peripheral surface is attached to the outer peripheral surface of the shaft 50 via radial bearings RB1 and RB2. Therefore, the output shaft 21 and the second rotating member 20 connected to the output shaft 21 can perform relative rotation in the circumferential direction with respect to the shaft 50.

  The input shaft 11 also includes a disk portion 11a and a cylindrical portion 11b that are the same as the output shaft 21 whose center axis coincides with the first rotation center axis R1. The cylindrical portion 11b has an inner peripheral surface attached to the outer peripheral surface of the cylindrical portion 21b of the output shaft 21 via radial bearings RB3 and RB4. The input shaft 11 can be rotated in the circumferential direction relative to the output shaft 21 by the radial bearings RB3 and RB4 and the following angular bearing AB.

  Here, a torque cam 71, an annular member 72, and an angular bearing AB are disposed between the outer peripheral planes of the disk portion 11 a of the input shaft 11 and the disk portion 21 a of the output shaft 21. The annular member 72 and the output shaft 21 can rotate relative to each other via the angular bearing AB. The torque cam 71 generates an axial force between the input shaft 11 and the annular member 72 and transmits rotational torque by engaging the engaging member on the input shaft 11 side and the engaging member on the annular member 72 side. And rotate them together. The axial force is transmitted to the first rotating member 10 and the second rotating member 20, and becomes a pressing force when they press each planetary ball 40.

  The sun roller 30 has a cylindrical shape whose center axis coincides with the first rotation center axis R1, and can be rotated relative to the shaft 50 in the circumferential direction by the radial bearings RB5 and RB6. A plurality of planetary balls 40 are radially arranged at substantially equal intervals on the outer peripheral surface of the sun roller 30. Accordingly, the outer peripheral surface of the sun roller 30 becomes a rolling surface when the planetary ball 40 rotates. The sun roller 30 can roll (rotate) each planetary ball 40 by its own rotation, or can rotate along with the rolling operation (rotation) of each planetary ball 40. Further, locking members 31 and 32 such as snap rings are disposed on the side surfaces of the radial bearings RB5 and RB6 so that the sun roller 30 is not moved in the axial direction with respect to the shaft 50.

  The planetary ball 40 is a rolling member that rolls on the outer peripheral surface of the sun roller 30. The planetary ball 40 is preferably a perfect sphere, but it may have a spherical shape at least in the rolling direction, for example, a rugby ball having an elliptical cross section. The planetary ball 40 is rotatably supported by a support shaft 41 that passes through the center of the planetary ball 40. For example, the planetary ball 40 can rotate relative to the support shaft 41 with the second rotation center axis R2 as a rotation axis (that is, rotate) by a bearing (not shown) disposed between the outer periphery of the support shaft 41. I am doing so. Accordingly, the planetary ball 40 can roll on the outer peripheral surface of the sun roller 30 around the support shaft 41. Both ends of the support shaft 41 are projected from the planetary ball 40. Note that there is a small backlash (gap) between the planetary ball 40 and the support shaft 41 due to the bearing or the like.

  The reference position of the support shaft 41 is a position where the second rotation center axis R2 is parallel to the first rotation center axis R1, as shown in FIG. The support shaft 41 is inclined from the reference position and from within the tilt plane including the rotation center axis (second rotation center axis R2) and the first rotation center axis R1 formed at the reference position. It can swing (tilt) with the planetary ball 40 between the positions. The tilt is performed with the center of the planetary ball 40 as a fulcrum in the tilt plane.

  The carrier 60 holds each protrusion of the support shaft 41 so as not to prevent the tilting movement of each planetary ball 40. The carrier 60 is, for example, arranged so that the first and second disk parts 61 and 62 having the center axis coinciding with the first rotation center axis R1 are opposed to each other, and the first and second disk parts 61 and 62 are opposed to each other. Are connected by a plurality of connecting shafts (not shown) to form a bowl shape as a whole. As a result, the carrier 60 has an open portion on the outer peripheral surface. Each planetary ball 40 is disposed between the first and second disk portions 61 and 62 and is in contact with the first rotating member 10 and the second rotating member 20 through the open portion. Here, in the carrier 60, the inner peripheral surfaces of the first and second disk portions 61 and 62 are fixed to the outer peripheral surface of the shaft 50.

  The continuously variable transmission 1 is provided with a guide portion for guiding the support shaft 41 in the tilting direction when each planetary ball 40 tilts. In this example, the guide portion is provided on the carrier 60. The guide portions are radial guide grooves 63 and 64 for guiding the support shaft 41 protruding from the planetary ball 40 in the tilt direction, and the first and second disk portions 61 and 62 are opposed to each other. A portion is formed for each planetary ball 40 (FIG. 2). That is, all the guide grooves 63 and all the guide grooves 64 are radially formed when viewed from the axial direction. The guide groove 63 has a groove width in the circumferential direction of the first disk portion 61. Similarly, the guide groove 64 has a groove width in the circumferential direction of the second disk portion 62. Each of the guide grooves 63 and 64 has a groove bottom along the locus of the end surface of the support shaft 41 at the time of tilting. A gap is provided in the groove width direction between the support shaft 41 and the guide grooves 63 and 64 in order to realize a tilting operation and to make it smooth. The clearance is set to a size that can cause a side slip between the sun roller 30 and the planetary ball 40 for the tilting operation, for example. The guide portion may be replaced with a guide hole having the same shape as the guide grooves 63 and 64.

  In this continuously variable transmission 1, when the tilt angle of each planetary ball 40 is the reference position, that is, 0 degrees, the first rotating member 10 and the second rotating member 20 have the same rotational speed (the same rotational speed). Rotate with. 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 each planetary ball 40 is tilted from the reference position, the distance from the central axis of the support shaft 41 to the contact portion with the first rotating member 10 changes and from the central axis of the support shaft 41. The distance to the contact portion with the second rotating member 20 changes. Therefore, 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 40 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 (speed ratio γ) between the first rotating member 10 and the second rotating member 20 can be changed steplessly by changing the tilt angle. it can. At the time of acceleration (γ <1) here, the upper planetary ball 40 in FIG. 1 is tilted counterclockwise on the paper surface and the lower planetary ball 40 is tilted clockwise on the paper surface. . Further, at the time of deceleration (γ> 1), the upper planetary ball 40 in FIG. 1 is tilted clockwise in the plane of the drawing, and the lower planetary ball 40 is tilted counterclockwise in the plane of the drawing.

  The continuously variable transmission 1 is provided with a transmission that changes its speed ratio γ. Since the gear ratio γ changes with a change in the tilt angle φ of the planetary ball 40, a tilting device that tilts each planetary ball 40 is used as the speed change device. Here, this transmission is provided with a disk-shaped iris plate (tilting element) 81. The iris plate 81 is attached to the shaft 50 via a radial bearing RB7 on the radially inner side, and can rotate relative to the shaft 50 about the first rotation center axis R1. An actuator (driving unit) such as a motor is used for the relative rotation. Further, the iris plate 81 exemplified here is disposed between the input side (contact portion side with the first rotating member 10) of each planetary ball 40 and the first disk portion 61. The iris plate 81 is formed with a throttle hole (iris hole) 82 into which one protrusion of the support shaft 41 is inserted. If the radial direction of the starting point is assumed to be the reference line L, the throttle hole 82 has an arc shape that moves away from the reference line L in the circumferential direction from the radially inner side to the radially outer side. (Fig. 3). 3 is a view seen from the direction of arrow A in FIG.

  Here, the relationship of the force when shifting the speed ratio γ toward the deceleration side (during deceleration) will be described. At the time of deceleration, as shown in FIG. 4 as viewed from the direction of arrow B in FIG. 1, the first rotating member is in contact with the first rotating member 10 in the planetary ball 40 (hereinafter referred to as “input side contact portion”). A tangential force Fin along the rotational direction of 10 works. On the other hand, a tangential force Fout opposite to the rotation direction of the second rotation member 20 acts on a contact portion with the second rotation member 20 (hereinafter referred to as “output side contact portion”). Since there are gaps between the planetary ball 40 and the support shaft 41, and between the support shaft 41 and the guide grooves 63 and 64, the support shaft 41 is driven by the tangential forces Fin and Fout in FIG. The shift angle φ1 is shifted in the counterclockwise direction. The shift angle φ1 is generally determined by the gap between the support shaft 41 and the guide grooves 63 and 64. The direction of the vector of the tangential force Fout is shifted by the shift angle φ1 of the support shaft 41. Further, due to the displacement of the support shaft 41, pressing forces F 3 and F 4 are applied to the iris plate 81 and the second disk portion 62 from the support shaft 41. In FIG. 4, for convenience of explanation, the gap between the support shaft 41 and the guide grooves 63 and 64 is drawn to be extremely larger than actual.

  Further, due to the shift of the support shaft 41, there is also a shift between the rotation direction of the sun roller 30 and the rotation direction of the planetary ball 40. Therefore, a side slip speed Vss determined by the rotational speed Vsun of the sun roller 30 and the rotational speed Vball of the planetary ball 40 is generated between the sun roller 30 and the planetary ball 40 (FIG. 5). The side slip velocity Vss causes a force to move the sun roller 30 in the axial direction (rightward in the drawing), but the movement of the sun roller 30 in the axial direction is restricted, so that the planetary ball 40 has its reaction. As a result, a force Fa that tries to move in the opposite direction (left direction in the drawing) is generated (FIG. 6). Since the planetary ball 40 is constrained at the three points of the first and second rotating members 10 and 20 and the sun roller 30, the force Fa is a force that moves the planetary ball 40 in the clockwise direction in FIG. It becomes. Further, due to the shift of the support shaft 41, a part of the tangential force Fout of the output side contact portion becomes a tangential force Fb that geometrically rotates the planetary ball 40 in the clockwise direction in FIG. 6 (FIGS. 6 and 7). ). FIG. 7 is a view of the planetary ball 40 viewed from the direction of arrow C in FIG. In this way, a tangential force due to the resultant force of the force Fa and the tangential force Fb acts on the surface of the planetary ball 40. The tangential force resulting from this resultant force becomes a rotational moment in the clockwise direction of FIG. 6, and a force F1 is applied from the support shaft 41 to the iris plate 81 (FIGS. 6 and 8). The force F <b> 1 is a force directed radially inward and is a tilting force when the planetary ball 40 is decelerated. This force F1 acts on the aperture hole 82 of the iris plate 81, but does not act on the guide grooves 63 and 64. “Δ” in FIG. 8 represents a contact angle between the support shaft 41 and the carrier 60, that is, a contact angle between the support shaft 41 and the throttle hole 82.

  Thus, the pressing force F3 in the circumferential direction and the tilting force F1 directed radially inward from the support shaft 41 act on the iris plate 81 (FIG. 8). At the time of deceleration, the tilting force F1 acts on the iris plate 81. Therefore, by rotating the iris plate 81 in the clockwise direction in FIG. 9, the protrusion on the input side of the support shaft 41 is caused by side slip. The planetary ball 40 moves inward in the radial direction along the guide groove 63 and tilts in the clockwise direction in FIG.

  By the way, in order to fix at a certain gear ratio at the time of deceleration, it is necessary to receive the resultant force of the circumferential pressing force F3 and the circumferential component F1a of the tilting force F1. Therefore, first, the pressing force F3 is received by the guide groove 63 of the first disk portion 61. Therefore, for the guide groove 63, the groove width W and the position of the side wall with respect to the support shaft 41 are set so that the support shaft 41 contacts the side wall of the guide groove 63 during deceleration. As a result, in the continuously variable transmission 1, only the circumferential component F1a of the tilting force F1 needs to be received when the speed ratio γ is fixed from the deceleration operation. Therefore, the continuously variable transmission 1 can reduce the energy required to fix the gear ratio γ from the deceleration operation and maintain the gear ratio γ, thereby improving the fuel efficiency of the vehicle. For example, the circumferential direction component F1a is received by the iris plate 81. A rotational moment is generated in the iris plate 81 to receive the circumferential component F1a. The rotational moment is the same magnitude as the rotational moment generated in the iris plate 81 due to the circumferential component F1a in each planetary ball 40 and is in the opposite direction. Hereinafter, this rotational moment is referred to as a gear ratio maintaining moment Mγ. The transmission ratio maintaining moment Mγ during deceleration is determined by the circumferential component F1a, the iris plate rotation radius Rp, and the number Nb of planetary balls 40 (Equation 1 below). In the continuously variable transmission 1, the gear ratio maintaining moment Mγ may be generated in the iris plate 81 in order to fix the gear ratio γ from the deceleration operation and maintain the gear ratio γ. Therefore, in the continuously variable transmission 1, the power required to generate the gear ratio maintaining moment Mγ is reduced, and the fuel efficiency of the vehicle is improved. The iris plate rotation radius Rp is the distance from the first rotation center axis R1 to the contact portion of the iris plate 81 with the support shaft 41.

    Mγ = F1a * Rp * Nb (1)

  Next, the relationship of force when shifting the speed ratio γ to the speed increasing side (at the time of speed increasing) will be described. Even at the time of acceleration, the tangential force along the rotational direction of the first rotating member 10 is applied to the input side contact portion on the surface of the planetary ball 40 as shown in FIG. 10 viewed from the direction of the arrow B in FIG. Fin works, and a tangential force Fout opposite to the rotation direction of the second rotating member 20 acts on the output side contact portion. On the input side of the support shaft 41, a force F3 in the same direction as the pressing force F3 during deceleration is applied to the iris plate 81 by the tangential forces Fin and Fout. Further, a force F4 in the same direction as the pressing force F4 during deceleration is applied to the output side of the support shaft 41 by the tangential forces Fin and Fout.

  Here, at the time of acceleration, it is necessary to shift the support shaft 41 in the direction opposite to that at the time of deceleration (clockwise direction in FIG. 10) by rotating the iris plate 81 in the counterclockwise direction in FIG. . That is, by generating the deviation of the support shaft 41, a side slip speed Vss determined by the rotation speed Vsun of the sun roller 30 and the rotation speed Vball of the planetary ball 40 is generated (FIG. 11), and the right side of the drawing by the side slip speed Vss. It is necessary to generate a force Fa to move in the direction on the planetary ball 40 (FIG. 12). The force Fa is a force for moving the planetary ball 40 counterclockwise in FIG. Due to the shift of the support shaft 41, a part of the tangential force Fout of the output side contact portion becomes a tangential force Fb that geometrically rotates the planetary ball 40 in the counterclockwise direction in FIG. 12 (FIGS. 12 and 13). ). FIG. 13 is a view of the planetary ball 40 viewed from the direction of arrow D in FIG. At the time of acceleration, a tangential force resulting from the resultant force Fa and tangential force Fb is applied to the surface of the planetary ball 40, and a rotational moment in the counterclockwise direction in FIG. The rotational moment causes a force F1 to act on the iris plate 81 from the support shaft 41 (FIGS. 12 and 14). The force F1 is a force directed outward in the radial direction, and is a tilting force when the planetary ball 40 is accelerated. This force F1 acts on the aperture hole 82 of the iris plate 81, but does not act on the guide grooves 63 and 64. At the time of acceleration, the rotational moment (hereinafter referred to as “acceleration moment”) Mu in FIG. 14 that overcomes the resultant force of the circumferential force F3 and the circumferential component F1a of the tilting force F1 in FIG. By acting on 81, a side slip is generated and the planetary ball 40 is tilted.

  In order to fix at a certain speed ratio γ during acceleration, it is necessary to receive the resultant force of the force F3 and the circumferential component F1a. However, at the time of acceleration, the force F3 cannot be received by the guide groove 63 as at the time of deceleration. Therefore, in the continuously variable transmission 1, the iris plate 81 receives the resultant force of the force F3 and the circumferential component F1a when the speed ratio γ is fixed from the speed increasing operation and maintained at the speed ratio γ. . The gear ratio maintaining moment Mγ at that time is the same magnitude as and opposite to the rotational moment generated in the iris plate 81 by the resultant force, and is smaller than the acceleration moment Mu. The speed ratio maintaining moment Mγ at the time of the acceleration is determined by the resultant force Fx, the iris plate rotation radius Rp, and the number Nb of the planetary balls 40 (Equation 2 below). Therefore, the acceleration moment Mu is set to a value larger than the gear ratio maintaining moment Mγ.

    Mγ = Fx * Rp * Nb (2)

  In this continuously variable transmission 1, the smaller the gear ratio maintaining moment Mγ, the smaller the power to the iris plate 81 required to generate the gear ratio maintaining moment Mγ, thereby improving the fuel efficiency of the vehicle. Here, when the speed ratio γ is fixed at the maximum speed, the speed ratio maintaining moment Mγ of Expression 2 is not required. That is, when the speed ratio γ is at the maximum speed, there is no need to rotate the iris plate 81 further in the speed increasing direction, so the speed ratio maintaining moment Mγ can be lowered, and the fuel efficiency of the vehicle can be improved. The support shaft 41 is changed from the deviation state of FIG. 10 to the deviation state of FIG. 4 at the time of deceleration by lowering the transmission ratio maintaining moment Mγ. Thereby, since the force F3 becomes the pressing force F3 at the time of deceleration, it is possible to set the speed ratio maintaining moment Mγ of Formula 1 based only on the circumferential component F1a of the tilting force F1 instead of the resultant force Fx. When the speed ratio γ is the maximum speed increase, the tilting force F1 is directed radially inward in the same manner as during deceleration. The reduction in the gear ratio maintaining moment Mγ can also be performed when the gear ratio γ is fixed during the speed increase.

  In this way, when the speed ratio γ is the maximum speed increase, the speed ratio maintaining moment Mγ can be reduced, so that the fuel efficiency of the vehicle can be improved to the same level as during deceleration. However, there is room for further improvement in fuel efficiency when the speed ratio γ is the maximum speed increase. For example, when the contact angle δ between the support shaft 41 and the throttle hole 82 is 0 degree, the tilting force F1 works all inward in the radial direction, and thus the circumferential component F1a that rotates the iris plate 81. Will not occur.

  Therefore, in the continuously variable transmission 1, the end portion on the highest speed side of the throttle hole 82 is formed in a concentric circular arc shape with the first rotation center axis R1 as the center. That is, the throttle hole 82 has an arc portion 82a extending on the highest speed side of the conventional throttle hole, and holds the support shaft 41 by the arc portion 82a when the speed ratio γ is the highest speed increase.

  The length of the arc portion 82 a is set to be equal to or greater than the groove width W of the guide portion 63. As a result, when the speed ratio γ is the maximum speed increase, the support shaft 41 can be continuously held by the arc portion 82a, and the force F3 can be received by the guide portion 63.

  In the continuously variable transmission 1, after the speed ratio γ reaches the maximum speed, the iris plate 81 is further rotated in the speed increasing direction, and the support shaft 41 is positioned on the arc portion 82a (FIG. 15). The rotation of the iris plate 81 is stopped after the support shaft 41 rides on the arc portion 82a. When the support shaft 41 is positioned on the arc portion 82a, the contact angle δ between the support shaft 41 and the throttle hole 82 is 0 degree, and therefore the tilting force F1 works inward in the radial direction. The force F3 is received by the guide groove 63. For this reason, the iris plate 81 is not subjected to a force for rotating itself. Therefore, in this continuously variable transmission 1, it is not necessary to generate the gear ratio maintenance moment Mγ when the gear ratio γ is the maximum speed increase, so that the fuel consumption of the vehicle can be improved.

  Here, the speed ratio γ of the highest speed is mainly used when starting the vehicle, and is therefore used more frequently than the speed reduction. Therefore, in the continuously variable transmission 1, the effect of improving the fuel efficiency is enhanced by providing the arc portion 82a on the highest speed side.

  Although only the case of the maximum speed increase is shown here, the throttle hole 82 may be provided with a similar arc portion at the end on the most deceleration side. As a result, the continuously variable transmission 1 does not need to generate the gear ratio maintaining moment Mγ not only at the maximum speed but also at the time of the maximum speed reduction, and further improves the fuel consumption of the vehicle.

  The throttle hole 82 has an arcuate main portion (other than the arc portion 82a) required for shifting. However, the main part may have any shape as long as the shape is suitable for changing the speed ratio γ. That is, the throttle hole may be formed in a concentric circular arc centered on the first rotation center axis R1 at the end portion on the most increased speed side and, if necessary, the end portion on the most decelerated side.

  Further, here, the iris plate 81 is disposed between each planetary ball 40 and the first disc portion 61. However, the iris plate 81 is disposed outside the first disc portion 61 (from the first disc portion 61 in FIG. 1). May also be arranged on the right side of the drawing), and the same effects as those described above can be obtained. In this case, the iris plate 81 may be formed with a throttle hole 82 similar to the above example, but may be a groove (throttle groove) having a shape equivalent to this.

  Furthermore, the iris plate may be disposed on the output side. For example, this iris plate may be disposed between each planetary ball 40 and the second disk portion 62, and on the outside of the second disk portion 62 (on the left side of the drawing with respect to the second disk portion 62 in FIG. 1). It may be arranged. In this case, the radially inner side of the throttle hole is the fastest speed increasing side, and the radially outer side is the fastest speed reducing side. Therefore, the arc portion is provided at the radially inner end. Also in this case, the throttle hole may be provided with an arc portion at the radially outer side, that is, at the end on the most deceleration side. Further, a groove (diaphragm groove) having a shape equivalent to that of the aperture hole may be formed in the iris plate arranged outside the second disk portion 62.

  Here, the arc portion described above eliminates the need for the gear ratio maintaining moment Mγ that resists the rotational moment caused by the circumferential component F1a of the tilting force F1. However, when there is a possibility that the iris plate rotates due to external force other than the force from the support shaft 41, for example, disturbance such as vibration, it is necessary to suppress the rotation. Accordingly, in the continuously variable transmission 1 in this case, it is necessary to generate a rotation suppression moment for stopping the rotation of the iris plate due to vibration or the like in the iris plate. Even in this case, since the gear ratio maintaining moment Mγ is not required, the fuel consumption of the vehicle can be sufficiently improved.

  However, in the continuously variable transmission 1, by providing the iris plate on the output side, the rotation suppression moment can be reduced as compared with the case where the iris plate is provided on the input side, and the fuel efficiency of the vehicle can be further improved. become. The reason is as follows. When the iris plate is provided on the input side, the iris plate rotation radius Rp becomes larger when the speed ratio γ is the highest speed increase than when the speed reduction ratio γ is the highest speed reduction. On the other hand, when the iris plate is provided on the output side, the iris plate rotation radius Rp becomes larger when the speed ratio γ is at the maximum speed than when the speed ratio is at the maximum speed. The rotation suppression moment increases as the iris plate rotation radius Rp increases, like the gear ratio maintenance moment Mγ. Therefore, when the iris plate is provided on the output side, the position of the speed ratio γ of the maximum speed that is used more frequently than the maximum speed reduction is disposed on the radially inner side of the throttle hole or throttle groove. This is because the rotation suppression moment can be reduced as compared with the case of the above.

  As described above, the continuously variable transmission according to the present invention is useful for a technique for improving fuel consumption performance.

1 continuously variable transmission 10 first rotating member (first rotating element)
20 Second rotating member (second rotating element)
30 Sun Roller (third rotating element)
40 Planetary ball (rolling member)
41 Support shaft 50 Shaft (transmission shaft)
60 Carrier (fixed element)
61 1st disk part 62 2nd disk part 63,64 Guide groove 81 Iris plate (tilting element)
82 Aperture hole 82a Arc portion R1 First rotation center axis R2 Second rotation center axis

Claims (3)

A transmission shaft as a fixed shaft serving as a rotation center;
First and second rotational elements capable of relative rotation having a common first rotational center axis disposed opposite to each other on the transmission shaft;
A rolling member having a second rotation center axis parallel to the first rotation center axis, and a plurality of radial members arranged radially about the first rotation center axis and sandwiched between the first and second rotation elements When,
A support shaft of the rolling member having the second rotation center axis and projecting both ends from the rolling member;
A third rotating element that is arranged on an outer peripheral surface and capable of rotating relative to the transmission shaft and the first and second rotating elements;
A fixing element fixed to the transmission shaft and formed with a guide groove or a guide hole for guiding each protrusion of the support shaft in the radial direction;
The first rotation element and each rolling member are provided with a tilting element that allows the rolling member to tilt by rotating relative to the transmission shaft about the first rotation center axis. The first rotation on the input side that becomes the gear ratio is changed by changing the contact point between the second rotation element and each rolling member by the tilting operation of each rolling member. A transmission for changing a rotation ratio between the element and the second rotating element on the output side;
With
It is a hole or groove that goes away in the circumferential direction with respect to the radial reference line as it goes outward in the radial direction, and one protruding portion of the inserted support shaft moves toward one end, The rolling member performs a tilting operation toward the speed increasing side, and the projecting portion moves toward the other end so that the rolling member performs a tilting operation toward the decelerating side. In the continuously variable transmission formed on the tilting element,
The throttle hole or the throttle groove is a portion formed in a concentric circular arc shape centered on the first rotation center axis, and holds one protrusion of the support shaft when the speed ratio is the maximum speed increase. A continuously variable transmission having a circular arc portion that can be used.   The throttle hole or the throttle groove is formed in a concentric circular arc shape centered on the first rotation center axis, and an arc portion capable of holding one protrusion of the support shaft when the speed ratio is at a maximum speed reduction. The continuously variable transmission according to claim 1, further comprising:   The continuously variable transmission according to claim 1 or 2, wherein the tilting element is disposed on the output side of the second rotating element with respect to each of the rolling members.

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