continuously variable transmission

Abstract

To provide a continuously variable transmission capable of preventing degradation of durability of a bearing supporting a planetary cone, and capable of preventing degradation of power transmission efficiency.SOLUTION: In a continuously variable transmission 1, a contact position P1 between conical surfaces 14d and 15d of a planetary cone 5 and a sun roller 2A, a contact position P2 between the conical surfaces 14a and 15d of the planetary cone 5 and a ring roller 6 are at a same position in an axial direction of an input shaft 2. The contact position P1 with the sun roller 2A on the conical surface 14d of the planetary cone 5, and the contact position P2 with the ring roller 6 on the conical surface 15d of the planetary cone 5 extend generally in parallel with the input shaft 2, respectively. The planetary cone 5 has an input side planetary cone 14 contacted with the sun roller 2A, an output side planetary cone 15 that is provided separately from the input side planetary cone 14, and is contacted with the ring roller 6, and an elastic member 5A that is provided in a compressed state between a bottom surface 14b of the input side planetary cone 14 and a bottom surface 15b of the output side planetary cone 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a continuously variable transmission. [Background technology]

[0002] A known continuously variable transmission that continuously changes the speed of power from a drive source is described in Patent Document 1. The continuously variable transmission described in Patent Document 1 includes a speed change ring that has its center on the central axis of an input shaft and is movable in the direction of the central axis, a plurality of planetary rollers that are arranged at equal intervals within an imaginary conical surface with an apex on the central axis and have a first conical portion that circumscribes the input roller and inscribes the output ring and a second conical portion that inscribes the speed change ring, a movable holder that holds the plurality of planetary rollers so that they can rotate about their respective rotation axes and revolve about the central axis, and a loading cam mechanism that generates a thrust load in the direction of the central axis, and is configured to perform continuous, continuously variable speed changes by controlling the position of the speed change ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6071309 Summary of the Invention [Problem to be solved by the invention]

[0004] In a continuously variable transmission using planetary rollers, it is desirable that the torque that can be transmitted without slippage be large. One way to increase the torque that can be transmitted is to increase the contact pressure at the contact points between the input rollers and the output ring and the planetary rollers, thereby increasing the normal force at each contact point. However, increasing the contact pressure can lead to a decrease in power transmission efficiency due to increased frictional resistance, and a decrease in durability due to increased loads acting on the bearings that support the planetary rollers.

[0005] Furthermore, in the continuously variable transmission described in Patent Document 1, part of the contact pressure of the input roller and output roller on the planetary roller acts to change the attitude of the planetary roller, so if the contact pressure is increased to increase the transmission torque, there is a risk that the durability of the planetary cone bearing will decrease and power transmission efficiency will decrease.

[0006] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a continuously variable transmission that can prevent a decrease in the durability of the bearings that support the planetary cones and can prevent a decrease in power transmission efficiency. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a continuously variable transmission that continuously changes the speed of the rotational power of the input shaft to the output shaft via the planetary cones, the continuously variable transmission comprising: an input member attached to an input shaft to which rotational power is input from a drive power source; an output member that transmits the rotational power input from the input member to an output shaft; a planetary cone formed in a truncated cone shape and having a conical surface where the input member and the output member come into contact; a support shaft that supports the planetary cone rotatably and movably in the axial direction; and a movement mechanism that changes the contact position of the input member on the conical surface of the planetary cone and the contact position of the output member on the conical surface of the planetary cone, wherein the contact position of the conical surface of the planetary cone with the input member and the contact position of the conical surface of the planetary cone with the output member are at the same position in the axial direction of the input shaft. a ball bearing having an outer ring fitted to a transmission case and an inner ring connected to the outer ring via rolling elements and fitted to the outer peripheral surface of the output shaft; a tapered roller bearing having an outer ring fitted to the inner peripheral surface of the output shaft and an inner ring connected to the outer ring via roller-shaped rolling elements and fitted to the outer peripheral surface of the input shaft; and a preload applying member provided in a compressed state between the outer ring of the ball bearing and the transmission case, for urging the ball bearing in the axial direction of the input shaft so as to apply a preload to the tapered roller bearing. It is characterized by: [Effects of the Invention]

[0008] Thus, according to the present invention, it is possible to provide a continuously variable transmission that can prevent a decrease in the durability of the bearings that support the planetary cones and prevent a decrease in power transmission efficiency. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a cross-sectional view of a continuously variable transmission according to an embodiment of the present invention, taken along the rotational center axis of an input shaft and the axis of a support shaft at high speed. [Figure 2] FIG. 2 is a cross-sectional view taken along the rotational center axis of the input shaft and the shift drum holding member in a continuously variable transmission according to one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of the rotational center axis of the input shaft and the axis of the support shaft of the continuously variable transmission according to one embodiment of the present invention at low speed. [Figure 4] FIG. 4 is a perspective view showing displacement of a contact surface when a planetary cone of a continuously variable transmission according to one embodiment of the present invention is skewed. DETAILED DESCRIPTION OF THE INVENTION

[0010] A continuously variable transmission according to one embodiment of the present invention includes an input member attached to an input shaft to which rotational power is input from a drive power source, an output member that transmits the rotational power input from the input member to an output shaft, a planetary cone formed in a truncated cone shape and having a conical surface where the input member and the output member contact, a support shaft that supports the planetary cone rotatably and axially movably, and a movement mechanism that changes the contact position of the input member on the conical surface of the planetary cone and the contact position of the output member on the conical surface of the planetary cone, wherein the contact position of the conical surface of the planetary cone with the input member and the contact position of the conical surface of the planetary cone with the output member are aligned in the axial direction of the input shaft. This prevents a decrease in durability of the bearings that support the planetary cone and prevents a decrease in power transmission efficiency. [Example]

[0011] Hereinafter, a continuously variable transmission according to an embodiment of the present invention will be described with reference to the drawings.

[0012] FIGS. 1 to 4 are diagrams illustrating a continuously variable transmission according to an embodiment of the present invention. Note that directions (up, down, left, and right) used in the description are for convenience of explanation. The cross-sectional views of FIGS. 1 to 3 are cross-sectional views of the upper side of a continuously variable transmission according to an embodiment of the present invention, and the up and down directions used in the description follow these drawings. That is, for the lower side, which is not shown, the up and down arrangement is reversed. In other words, based on the rotational axis of the input shaft, the direction radially away from the rotational axis of the input shaft is described as up, and conversely, the direction radially toward the rotational axis of the input shaft is described as down. The left and right directions also follow the drawings. That is, the side where the input shaft 2, to which the driving power source is connected, is located is the right side, and this direction is also referred to as the input side or input shaft side. Conversely, the side where the output shaft 3, to which the drive wheels are connected, is located is the left side, and this direction is also referred to as the output side or output shaft side. FIG. 4 is a diagram illustrating a planetary cone 5 as viewed from above, and the front-to-rear direction in this figure follows the coordinate indications in the figure.

[0013] 1, a continuously variable transmission 1 is mounted on a vehicle and continuously changes the speed of rotational power from a driving power source 10 such as an internal combustion engine or a motor, and transmits the rotational power to driving wheels (not shown).

[0014] The continuously variable transmission 1 includes a transmission case 41, an input shaft 2 to which rotational power is input from a driving power source 10, a sun roller 2A as an input member attached to the input shaft 2, a ring roller 6 as an output member that transmits the rotational power input from the sun roller 2A to the output shaft 3, and the output shaft 3.

[0015] The continuously variable transmission 1 also includes a carrier 4, a plurality of planetary cones 5 formed in a truncated cone shape having conical surfaces 14d, 15d where the sun roller 2A and the ring roller 6 come into contact, and a support shaft 16 that supports the planetary cones 5 so that they can rotate freely and move freely in the axial direction.

[0016] Furthermore, the continuously variable transmission 1 is equipped with a movement mechanism 30, which moves the planetary cone 5 along the axial direction of the input shaft 2 to change a contact position P1 of the sun roller 2A on the conical surface 14d of the planetary cone 5 and a contact position P2 of the ring roller 6 on the conical surface 15d of the planetary cone 5. Through this change, the continuously variable transmission 1 continuously changes the speed of the rotational power of the input shaft 2 via the planetary cone 5 and outputs it to the output shaft 3.

[0017] The transmission case 41 is made up of a right case 42 and a left case 43 connected by a bolt 41A to the left end of the right case 42. The interior of the transmission case 41 accommodates the various components that make up the continuously variable transmission 1, which will be described later, and traction oil.

[0018] The input shaft 2 extends in the left-right direction, and a driving force source 10 is connected to the right end of the input shaft 2. An annular expanded diameter portion 2a that protrudes radially is formed in the longitudinal center of the input shaft 2, and a sun roller 2A is attached to the outer periphery of this expanded diameter portion 2a with bolts 2b. The sun roller 2A has an annular shape that is coaxial with the input shaft 2 and is formed with a large diameter so that it protrudes from the input shaft 2.

[0019] An axis 2r extending in the left-right direction along the input shaft 2 is the central axis of rotation of the input shaft 2, and the input shaft 2 rotates around the axis 2r. The direction of the axis 2r is referred to as the axial direction.

[0020] The output shaft 3 is disposed coaxially with the axis 2r of the input shaft 2. More specifically, the output shaft 3 is disposed coaxially on the left end side of the input shaft 2. The output shaft 3 includes a cylindrical shaft portion 3A protruding from the left case 43, a disk-shaped expanded diameter portion 3B extending radially outward from the right end of the shaft portion 3A, a large-diameter cylindrical portion 3C extending rightward from the outer peripheral end of the expanded diameter portion 3B into which the left end of the input shaft 2 is inserted, and a disk-shaped expanded diameter portion 3D extending radially outward from the right end of the large-diameter portion 3C. The shaft portion 3A, the expanded diameter portions 3B and 3D, and the large diameter portion 3C are configured from a single member.

[0021] The output shaft 3 further has a cylindrical output drum 3E. The output drum 3E is disposed coaxially with the input shaft 2, extends rightward from the radial outer periphery of the enlarged diameter portion 3D, and increases in diameter in a direction radially away from the input shaft 2 as it moves to the right. A ring roller 6 is attached to the large-diameter end portion, which is the right end of the output drum 3E, with a bolt 6a. The ring roller 6 has an annular shape coaxial with the input shaft 2, has a small diameter so as to protrude inward beyond the large-diameter end portion at the right end of the output drum 3E, and is formed with a contact portion for contacting the conical surface 15d of the planet cone 5.

[0022] The output drum 3E is composed of separate members from the shaft portion 3A, the enlarged diameter portions 3B and 3D, and the large diameter portion 3C. The left end of the output drum 3E, which is the small diameter side end, is connected to the enlarged diameter portion 3D and integrated into one body. In other words, the output shaft 3 has a joined structure in which the output drum 3E is composed of separate members from the other members. This improves the workability of the output shaft 3 manufacturing process and the productivity of the output shaft 3.

[0023] A final drive gear (not shown) is attached to the shaft portion 3A of the output shaft 3, and the final drive gear meshes with a final driven gear of a differential device (not shown). The differential device is connected to left and right drive wheels via left and right drive shafts (not shown). The differential device distributes the rotational power of the drive power source 10 transmitted from the output shaft 3 to the left and right drive shafts and transmits it to the left and right drive wheels.

[0024] The carrier 4 is disposed around the input shaft 2. The carrier 4 holds an end 16A (right end) on the input shaft 2 side of a support shaft 16 that supports multiple planetary cones 5 so that they can rotate (rotate on their axes). In other words, the input shaft 2 is disposed so as to pass through the carrier 4, and the multiple planetary cones 5 are disposed so as to surround the input shaft 2.

[0025] The carrier 4 holds the support shaft 16 via a self-aligning bearing 17. The self-aligning bearing 17 has an outer ring 17a, a sphere 17b, and an inner ring 17c rotatably connected to the outer ring 17a via the sphere 17b. The self-aligning bearing 17 is a self-aligning ball bearing using the sphere 17b. The self-aligning bearing 17 supports the end 16A (right end) of the support shaft 16 on the input shaft 2 side, which is attached to the inner ring 17c, so that it can swing freely. The self-aligning bearing 17 supports the support shaft 16 so that it does not displace in the direction of the axis 16r of the support shaft 16. The self-aligning bearing 17 constitutes the second support portion 47.

[0026] 2, a shift flange 32 (described later) is in contact with the inner peripheral surface of the carrier 4 via a ball spline 4c. The ball spline 4c restricts relative rotation between the carrier 4 and the shift flange 32 around the input shaft 2 and allows relative movement in the axial direction of the input shaft 2. The shift flange 32 is disposed to pass through the carrier 4, and the input shaft 2 is disposed to pass through the shift flange 32. In other words, the shift flange 32 is disposed to surround the input shaft 2 on the inner diameter side of the carrier 4.

[0027] The carrier 4 is disposed closer to the input shaft 2 (to the right) than the sun roller 2A in the axial direction of the input shaft 2. A guide groove 40 is formed on the outer periphery of the carrier 4, extending in the axial direction of the input shaft 2 and opening to the outer diameter side (outside). A guide follower 45 fixed to the transmission case 41 is disposed in the internal space of the guide groove 40, and the guide follower 45 abuts against the guide groove 40. The guide follower 45 is fixed to the transmission case 41 by a bolt 44 inserted from the outside in a direction substantially perpendicular to the input shaft 2. The guide follower 45 and the guide groove 40 restrict rotation of the carrier 4 relative to the transmission case 41 and allow and guide movement of the carrier 4 in the axial direction of the input shaft 2. The guide follower 45 is configured similarly to a ball bearing and has a contact portion 45A that corresponds to the outer ring of the ball bearing and abuts against the guide groove 40. Then, as the contact portion 45A rotates, the frictional resistance at the contact portion between the guide follower 45 and the guide groove 40 is reduced, and the carrier 4 can move easily in the direction in which the guide groove 40 extends.

[0028] In this way, rotation of the carrier 4 around the input shaft 2 is restricted by the guide follower 45 abutting within the guide groove 40, and therefore the shift flange 32, which is connected to the carrier 4 via the ball spline 4c, is also restricted from rotating relative to the transmission case 41. Furthermore, movement of the carrier 4 in the axial direction of the input shaft 2 is permitted and guided by the guide groove 40 and the ball spline 4c. Note that the guide follower 45, which is disposed in the internal space of the guide groove 40, is fixed to the transmission case 41 by threading the male thread formed on the bolt 44 with the female thread formed on the guide follower 45. In other words, the bolt 44 and the guide follower 45 are threadedly engaged with each other to sandwich the transmission case 41, thereby being fixed to the transmission case 41. Furthermore, the diameter of the hole in the transmission case 41 through which the bolt 44 is inserted is formed larger than the diameter of the bolt 44, and a gap is provided between the transmission case 41 and the bolt 44, so that the positions of the bolt 44 and the guide follower 45 relative to the transmission case 41 can be finely adjusted within the range of that gap. In other words, the position of the guide follower 45 can be finely adjusted to match the position of the guide groove 40 of the carrier 4.

[0029] A restricting portion 32A that protrudes radially outward is formed on the left end of the outer peripheral surface of the shift flange 32. A circlip 32B that protrudes radially outward is attached to the right end of the outer peripheral surface of the shift flange 32. When the amount of relative movement of the carrier 4 in the axial direction of the input shaft 2 with respect to the shift flange 32 increases, the restricting portion 32A and the circlip 32B come into contact with the carrier 4, restricting further relative movement of the carrier 4. In other words, the restricting portions 32A and the circlips 32B that limit the range of movement of the carrier 4 are arranged on both sides of the ball spline 4c in the axial direction of the shift flange 32.

[0030] In FIG. 1 , the planetary cone 5 is supported by the carrier 4 and the shift drum 34 via a support shaft 16. The carrier 4 is disposed closer to the input shaft 2 than the sun roller 2A in the axial direction of the input shaft 2 with respect to the planetary cone 5. The shift drum 34 is disposed closer to the output shaft 3 than the sun roller 2A in the axial direction of the input shaft 2 with respect to the planetary cone 5. A needle bearing 63 is held on the inner periphery of the shift drum 34, and the needle bearing 63 rotatably supports the input shaft 2. In other words, the input shaft 2 is disposed to pass through the shift drum 34, and the shift drum 34 is supported by the input shaft 2 via the needle bearing 63 so as to be relatively rotatable.

[0031] The planetary cones 5 include an input planetary cone 14 with a truncated cone shape that contacts the sun roller 2A, and an output planetary cone 15 that is provided separately from the input planetary cone 14 and is also truncated cone shape that contacts the ring roller 6. The input planetary cone 14 and the output planetary cone 15 are supported by the support shaft 16 so that they can rotate relative to the support shaft 16, with their bottom surfaces 14b, 15b facing each other. In other words, the input planetary cone 14 and the output planetary cone 15 are rotatably attached to the support shaft 16 in opposite directions so that their bottom surfaces 14b, 15b face each other. The input planetary cone 14 and the output planetary cone 15 are supported by the support shaft 16 so that they can move in the direction of the axis 16r within the range of the self-aligning bearing 17 and guide roller 35 at the end of the support shaft 16. In the assembled state, the input side planetary cone 14 abuts against the sun roller 2A, thereby restricting the position of the output shaft 3 side (left end side) of the support shaft 16, and the output side planetary cone 15 abuts against the ring roller 6, thereby restricting the position of the input shaft 2 side (right end side) of the support shaft 16.

[0032] The planetary cone 5 has a ball cam mechanism 21 between the input planetary cone 14 and the output planetary cone 15. The ball cam mechanism 21 connects the bottom surface 14b of the input planetary cone 14 and the bottom surface 15b of the output planetary cone 15, and transmits power from the input planetary cone 14 to the output planetary cone 15, or from the output planetary cone 15 to the input planetary cone 14.

[0033] The ball cam mechanism 21 has a plurality of input cam grooves 14f formed in the bottom surface 14b of the input planetary cone 14, a plurality of output cam grooves 15f formed in the bottom surface 15b of the output planetary cone 15, and a sphere 20 accommodated so as to straddle the input cam grooves 14f and the output cam grooves 15f. The input cam grooves 14f and the output cam grooves 15f are formed in equal numbers and extend in the circumferential direction around the axis 16r of the support shaft 16.

[0034] The input-side cam groove 14f and the output-side cam groove 15f each have an arc-shaped cross section taken along the radial direction centered on the axis 16r of the support shaft 16, with the same radius as the radius of the sphere 20. Therefore, the sphere 20, which is disposed in the space between the input-side cam groove 14f and the output-side cam groove 15f, does not move in the radial direction centered on the axis 16r of the support shaft 16. The input-side cam groove 14f and the output-side cam groove 15f are each formed so that their depths vary in the circumferential direction. Specifically, the input-side cam groove 14f and the output-side cam groove 15f are deep in the circumferential center and gradually become shallower as they approach both ends in the circumferential direction. In other words, the input-side cam groove 14f and the output-side cam groove 15f are formed so that they are shallower toward the circumferential ends. Ball 20 is free to roll in the circumferential direction along input-side cam groove 14f and output-side cam groove 15f, and input-side cam groove 14f and output-side cam groove 15f are set so that the groove width dimension in the radial direction centered on axis 16r of support shaft 16 is approximately the same as the dimension of ball 20 abutting against the groove bottom at that position (the cross-sectional dimension when cut at bottom surfaces 14b, 15b of planet cone 5). For this reason, input-side cam groove 14f and output-side cam groove 15f are formed so that the groove width is wide in the circumferential center and gradually narrows from the circumferential center to both ends in the circumferential direction.

[0035] The input cam groove 14f and the output cam groove 15f are formed in positions that face each other when the bottom surfaces 14b and 15b are aligned, and have the same shape. The input planetary cone 14 and the output planetary cone 15 are also formed in the same shape. In other words, the input planetary cone 14 and the output planetary cone 15 have the same shape and are interchangeable, improving productivity.

[0036] In other words, the planetary cone 5 can be configured to have the same shape even if the input side planetary cone 14 is swapped with the position of the output side planetary cone 15, and the output side planetary cone 15 is swapped with the position of the input side planetary cone 14.

[0037] The input planetary cone 14 transmits power to the output planetary cone 15 via a sphere 20. The sphere 20 is made of, for example, a steel ball, but is not limited to a steel ball.

[0038] In this embodiment, the dimensional tolerances are set so as to provide a gap at contact position P1 between the conical surface 14d of the input-side planetary cone 14 of the planetary cone 5 and the sun roller 2A, and the dimensional tolerances are set so as to provide a gap at contact position P2 between the conical surface 15d of the output-side planetary cone 15 of the planetary cone 5 and the ring roller 6. In other words, the dimensions of each part are set so that contact positions P1 and P2 do not become press-fit. This makes it easy to assemble the planetary cone 5 into the continuously variable transmission 1.

[0039] In the planetary cones 5, when power is input from the sun roller 2A to the input planetary cone 14, the input planetary cone 14 and the output planetary cone 15 temporarily rotate relative to each other due to a torque difference, causing their rotational positions to shift. In other words, when power is input from the sun roller 2A to the input planetary cone 14, the rotation of the output planetary cone 15 temporarily lags behind the rotation of the input planetary cone 14 due to contact between the output planetary cone 15 and the ring roller 6 or the inertia of the output planetary cone 15 due to its own weight. This causes the relative rotational positions of the input planetary cone 14 and the output planetary cone 15 to shift, causing the spheres 20 to move (roll) inside the input cam groove 14f and the output cam groove 15f. When the spheres 20 move (roll) inside the input cam groove 14f and the output cam groove 15f, the ball cam mechanism 21 is activated. In this case, the input side planetary cone 14 and the output side planetary cone 15 are separated in the axial direction of the support shaft 16 by the sphere 20 .

[0040] In other words, when the ball 20 moves, the positions of the input side cam groove 14f and the output side cam groove 15f with which the ball 20 abuts change, and the ball 20 is displaced to a location of a different depth. As a result, the amount by which the ball 20 protrudes from the input side cam groove 14f and the output side cam groove 15f changes, and the input side planetary cone 14 and the output side planetary cone 15 move closer or farther apart in the axial direction of the support shaft 16.

[0041] That is, when the depths of the input cam groove 14f and the output cam groove 15f in which the spheres 20 are located become shallower, the input planetary cone 14 and the output planetary cone 15 move apart in the axial direction of the support shaft 16, and when the relative movement between the input planetary cone 14 and the output planetary cone 15 in the rotational direction subsides, they rotate together via the spheres 20. This situation occurs when the torque to be transmitted increases, and the input planetary cone 14 and the output planetary cone 15 move apart in the axial direction of the support shaft 16, resulting in stronger contact between the input planetary cone 14 and the sun roller 2A, and between the output planetary cone 15 and the ring roller 6, enabling greater torque transmission.

[0042] On the other hand, when the depths of the input cam groove 14f and the output cam groove 15f in which the spheres 20 are located become deeper, the input planetary cone 14 and the output planetary cone 15 move closer to the axial direction of the support shaft 16, and when the relative movement between the input planetary cone 14 and the output planetary cone 15 in the rotational direction subsides, they rotate integrally via the spheres 20. This situation occurs when the torque to be transmitted decreases, and as the input planetary cone 14 and the output planetary cone 15 move closer to the axial direction of the support shaft 16, the force pressing the input planetary cone 14 against the sun roller 2A and the force pressing the output planetary cone 15 against the ring roller 6 weakens, eliminating pressing forces unnecessary for torque transmission and improving durability.

[0043] The input side planetary cone 14 and the output side planetary cone 15 are connected via a ball cam mechanism 21 and rotate integrally about the axis 16r of the support shaft 16, except for relative movement (misalignment) due to torque difference.

[0044] Even when the input and output planetary cones 14, 15 are at their farthest distance from each other in the axial direction of the support shaft 16, the spheres 20 do not come out of the input and output cam grooves 14f, 15f. In other words, the input and output planetary cones 14, 15 move in the axial direction of the support shaft 16 within a distance that is smaller than the diameter of the spheres 20.

[0045] In addition, both circumferential ends of the input side cam groove 14f and the output side cam groove 15f abut against the sphere 20, functioning as stoppers that restrict further deviation (relative rotation angle) between the input side planetary cone 14 and the output side planetary cone 15.

[0046] The planetary cone 5 has an elastic member 5A that is compressed between the bottom surface 14b of the input planetary cone 14 and the bottom surface 15b of the output planetary cone 15. The elastic member 5A is made of, for example, a disc spring or a wave washer, and generates a restoring force when compressed. Even when the planetary cone 5 is not transmitting torque, the biasing force (restoring force) of the elastic member 5A presses the input planetary cone 14 against the sun roller 2A and presses the output planetary cone 15 against the ring roller 6. This prevents the input planetary cone 14 from spinning freely relative to the sun roller 2A, and prevents the output planetary cone 15 from spinning freely relative to the ring roller 6, allowing the planetary cones 5 to transmit torque without slipping. In other words, when power is input from the sun roller 2A to the input planetary cone 14, the force from the abutting ring roller 6 immediately causes relative rotation between the input planetary cone 14 and the output planetary cone 15, regardless of the magnitude of inertia due to the weight of the output planetary cone 15, thereby operating the ball cam mechanism 21. The shape and installation position of the elastic member 5A are determined so as not to affect the operation of the ball cam mechanism 21 and to avoid interference with the input cam groove 14f, the output cam groove 15f, and the sphere 20, and the elastic member 5A is attached to the input planetary cone 14 or the output planetary cone 15.

[0047] An end 16B (left end) of the support shaft 16 on the output shaft 3 side is supported so as to be able to swing freely by a first support portion 46. The first support portion 46 is composed of a spherical guide roller 35 that is held so as to be able to swing freely in a groove 34A formed in the shift drum 34, and a bearing 54 provided inside the guide roller 35. The bearing 54 is made of a needle bearing and supports the end 16B of the support shaft 16 with respect to the guide roller 35. The groove 34A formed in the shift drum 34 is a spiral groove that is formed so as to gently wrap around the input shaft 2 and is formed so as to displace in the circumferential direction as the input shaft 2 is displaced in the axial direction. The groove 34A not only holds the guide roller 35 so as to be able to swing freely, but also slightly moves the guide roller 35 in the circumferential direction of the input shaft 2 as the shift drum 34 is displaced in the axial direction of the input shaft 2.

[0048] The support shaft 16 is installed in an inclined position with respect to the axis 2r of the input shaft 2 so that the axis 16r is inclined relative to the axis 2r of the input shaft 2. Specifically, the axis 16r of the support shaft 16 is installed inclined with respect to the axis 2r of the input shaft 2 so that the center axis of the support shaft 16 approaches the input shaft 2 as it moves leftward.

[0049] When the shift drum 34 is moved in the direction of the axis 2r of the input shaft 2 by the movement mechanism 30, the planetary cone 5 moves in the direction of the axis 2r of the input shaft 2 together with the shift drum 34, the shift drum holding member 33, the shift flange 32 and the carrier 4.

[0050] A plurality of planetary cones 5 are provided at equal intervals in the circumferential direction so as to surround the input shaft 2 radially outward of the input shaft 2. This allows the normal forces acting from each planetary cone 5 on the sun roller 2A and the ring roller 6 to cancel each other out. Furthermore, in a continuously variable transmission 1 according to one embodiment of the present invention, an odd number of planetary cones 5 are provided. This increases the degree of freedom in installing the planetary cones 5, since there are no multiple support shafts 16 on a plane including the axis 2r of the input shaft 2.

[0051] The sun roller 2A is in contact with the conical surface 14d of the input side planetary cone 14, and the ring roller 6 is in contact with the conical surface 15d of the output side planetary cone 15.

[0052] The input side planetary cone 14 is installed in such a position that the generatrix of its conical surface 14d extends parallel to the axis 2r of the input shaft 2 and forms a conical surface that is always in contact with the sun roller 2A.

[0053] The output side planetary cone 15 is installed in such a position that the generatrix of its conical surface 15d extends parallel to the axis 2r of the input shaft 2 and forms a conical surface that is in constant contact with the ring roller 6.

[0054] In other words, even if the planetary cone 5 moves in the direction of the axis 2r of the input shaft 2, it moves in the direction of the axis 2r of the input shaft 2 while maintaining an attitude such that the conical surface that is always in contact with the sun roller 2A and the conical surface that is always in contact with the ring roller 6 are parallel to the axis 2r of the input shaft 2, thereby maintaining contact between the conical surface 14d and the sun roller 2A and also between the conical surface 15d and the ring roller 6.

[0055] As shown in FIG. 2, the movement mechanism 30 includes a gear shift operating unit 31 connected to the shift drum 34, and the gear shift operating unit 31 is operated externally by an actuator or the like to move the shift drum 34 in the axial direction of the input shaft 2.

[0056] The movement mechanism 30 further includes a shift flange 32 and a shift drum holding member 33. The shift flange 32 is provided on the outer circumferential side of the gearshift operating unit 31 and on the inner circumferential side of the carrier 4, and moves in the axial direction of the input shaft 2 when the gearshift operating unit 31 is operated. The shift drum holding member 33 connects the shift flange 32 and the shift drum 34 so that they can move integrally in the axial direction of the input shaft 2. The shift drum holding member 33 is a columnar member arranged between the planetary cones 5 to extend in the axial direction of the input shaft 2, and a plurality of shift drum holding members 33 are provided. Here, the carrier 4 is provided so as to be movable in the axial direction of the input shaft 2 by the guide follower 45 and the guide groove 40, but not rotatable around the input shaft 2. Furthermore, the shift flange 32 is movable in the axial direction of the input shaft 2 by the carrier 4 via the ball spline 4c, but not rotatable around the input shaft 2. Therefore, the shift drum 34 connected to the shift flange 32 by the shift drum holding member 33 is also movable in the axial direction of the input shaft 2 and is provided non-rotatable around the input shaft 2 .

[0057] The gearshift operating unit 31 has a disk-shaped operating portion 31A that extends radially, and a shaft portion 31B with a feed screw formed on its outer peripheral surface. The shift flange 32 is formed in an annular shape so as to surround the outer peripheral portion of the shaft portion 31B of the gearshift operating unit 31. A feed screw that threadably engages with the shaft portion 31B is formed on the inner peripheral surface of the shift flange 32. A shift drum holding member 33 is connected to the left end of the shift flange 32. The shift drum holding member 33 is formed in a rod shape that extends leftward from the shift flange 32, passing above the sun roller 2A. The left end of the shift drum holding member 33 is connected to the shift drum 34.

[0058] In the movement mechanism 30, when the gear shift operating unit 31 is rotated externally, the shift flange 32 is moved in the axial direction of the input shaft 2 by the feed screw mechanism. Then, the shift drum 34, which is connected to the shift flange 32 via the shift drum holding member 33, moves integrally with the shift flange 32 in the axial direction of the input shaft 2. When the shift drum 34 moves, the position of the groove 34A of the shift drum 34 relative to the guide roller 35 changes. As described above, the groove 34A is formed as a spiral groove around the input shaft 2, and as the shift drum 34 moves in the axial direction, the position of the guide roller 35 moves slightly in the circumferential direction of the input shaft 2. When this happens, the support shaft 16 tilts in a twisting direction relative to the input shaft 2, and the attitude of the planetary cone 5 changes, resulting in a tilted (skewed) state. The tilted (skewed) planetary cone 5 receives a force in a direction that eliminates the tilt of the support shaft 16, and the guide roller 35 moves within the groove 34A of the shift drum 34 to eliminate the tilt. The movement ends when the tilt is eliminated. The position of the guide roller 35 where the tilt is eliminated is the position within the groove 34A where the guide roller 35 was located before the shift drum 34 moved. This movement occurs automatically and immediately when the shift drum 34 moves. Therefore, it appears as if the guide roller 35 held by the shift drum 34 moves together with the shift drum 34, and the planetary cone 5 moves in the same direction. At this time, the carrier 4, separate from the shift flange 32, moves in the same direction as the movement of the planetary cone 5 due to the ball spline 4c. In this embodiment, the carrier 4 moves to a position where the tilt is eliminated due to a component force generated by the tilt of the planetary cone 5 caused by the movement of the shift flange 32.

[0059] In this embodiment, the shift flange 32 moves in the axial direction by a feed screw mechanism, but the shift flange 32 may also be moved axially directly by an actuator without using a feed screw mechanism. Similarly, when the shift drum 34 moves in the other axial direction, the planetary cone 5 moves, and the carrier 4 moves in the moving direction of the shift drum 34 along with the planetary cone 5. These actions maintain the appropriate posture and arrangement of the planetary cone 5, and the positions of the shift drum 34 and the carrier 4 are adjusted accordingly, making it possible to eliminate the need for a part that defines the positional relationship between the first support portion 46 and the second support portion 47, facilitating dimensional control during part manufacturing and improving productivity.

[0060] An operating portion 31A of the gearshift operating portion 31 is disposed outside the transmission case 41. A shaft portion 31B of the gearshift operating portion 31 is disposed inside the transmission case 41 and surrounds the outer peripheral surface of the input shaft 2.

[0061] A seal member 64 is provided between the inner circumferential surface of the operating unit 31A and the outer circumferential surface of the input shaft 2. A seal member 65 is provided between the outer circumferential surface of the right end of the shaft portion 31B of the gearshift operating unit 31 and the inner circumferential surface of the right end of the transmission case 41. Furthermore, a seal member 66 is provided between the outer circumferential surface of the shaft portion 3A of the output shaft 3 and the inner circumferential surface of the left end of the transmission case 41. These seal members 64, 65, 66 prevent traction oil from leaking from the inside to the outside of the transmission case 41 and prevent foreign matter from entering from the outside to the inside of the transmission case 41.

[0062] A ball bearing 61 is provided between the inner peripheral surface of the right end of shaft portion 31B of gearshift operating unit 31 and the outer peripheral surface of input shaft 2. A ball bearing 62 is provided between the inner peripheral surface of the left end of shaft portion 31B of gearshift operating unit 31 and the outer peripheral surface of input shaft 2.

[0063] A ball bearing 53 is provided near the right end of shaft portion 31B of gearshift operating device 31 and to the left of seal member 65. Ball bearing 53 has a spherical rolling element 53b and an outer ring 53a and an inner ring 53c that are relatively rotatable via rolling element 53b. Inner ring 53c of ball bearing 53 is fitted onto shaft portion 31B and is prevented from coming off in the axial direction by a circlip 53d attached to shaft portion 31B. Outer ring 53a of ball bearing 53 is fitted onto the inner circumferential surface of the right end portion of transmission case 41.

[0064] In this manner, in this embodiment, the gearshift operating device 31 is rotatably supported with respect to the transmission case 41 by the ball bearing 53. In addition, the right end portion of the input shaft 2 is rotatably supported with respect to the gearshift operating device 31 by the ball bearings 61 and 62.

[0065] In the continuously variable transmission 1 of this embodiment, the contact position P1 between the conical surface 14d of the planetary cone 5 and the sun roller 2A and the contact position P2 between the conical surface 15d of the planetary cone 5 and the ring roller 6 are located at the same position in the axial direction of the input shaft 2. In other words, the sun roller 2A and the ring roller 6 are located on the same cross section perpendicular to the axis of the input shaft 2 and face each other in the radial direction of the input shaft 2. Therefore, except in the tilted (skewed) state described above, the contact pressure between the sun roller 2A and the ring roller 6 does not generate a rotational moment that would tilt the axis center 16r of the planetary cone 5.

[0066] In the continuously variable transmission 1 of this embodiment, a contact position P1 of the sun roller 2A with the conical surface 14d of the planetary cone 5 and a contact position P2 of the ring roller 6 with the conical surface 15d of the planetary cone 5 each extend substantially parallel to the input shaft 2. In other words, the contact surfaces of the sun roller 2A and the ring roller 6 with the planetary cone 5 have a cylindrical shape extending substantially parallel to the input shaft 2.

[0067] The continuously variable transmission 1 of this embodiment is equipped with a ball bearing 50. The ball bearing 50 has an outer ring 50a fitted to the transmission case 41, and an inner ring 50c connected to the outer ring 50a via spherical rolling elements 50b and fitted to the outer peripheral surface of the output shaft 3. The outer ring 50a is fitted to the inner peripheral surface of a cylindrical bearing holder 43A formed near the left end of the transmission case 41. The inner ring 50c is fitted to the outer peripheral surface of a cylindrical large-diameter portion 3C formed on the output shaft 3.

[0068] The continuously variable transmission 1 also includes a tapered roller bearing 51. The tapered roller bearing 51 has an outer ring 51a fitted to the inner peripheral surface of the output shaft 3, and an inner ring 51c connected to the outer ring 51a via roller-shaped rolling elements 51b (rollers with conical surfaces) and fitted to the outer peripheral surface of the input shaft 2. The outer ring 51a is fitted to the inner peripheral surface of the large-diameter portion 3C of the output shaft 3. The inner ring 51c is fitted to the outer peripheral surface of a cylindrical bearing holder 51d attached to the left end of the input shaft 2. The bearing holder 51d restricts rightward movement of the inner ring 51c. The right end of the inner ring 51c abuts against the left end of the enlarged-diameter portion 3D of the bearing holder 51d. The rolling elements 51b are inclined to support an axial load in a direction that brings the input shaft 2 and the output shaft 3 closer together. In this way, the tapered roller bearing 51 bears the axial and radial loads acting between the input shaft 2 and the output shaft 3. Therefore, the tapered roller bearing 51 also bears the axial and radial loads acting between the sun roller 2A and the ring roller 6. In particular, it can effectively bear the load that occurs in the axial direction of the input shaft 2 when the input shaft 2 is in the aforementioned tilted (skewed) state, and the load that occurs in the axial direction of the input shaft 2 when the ball cam mechanism 21 is operating.

[0069] Furthermore, the continuously variable transmission 1 is equipped with a preload applying member 52. The preload applying member 52 is provided in a compressed state between the ball bearing 50 and the transmission case 41. The preload applying member 52 is made of a diaphragm spring, a wave washer, or the like, and urges the ball bearing 50 in the axial direction of the input shaft 2 so as to apply a preload to the tapered roller bearing 51. The preload applying member 52 also suppresses axial play of the input shaft 2 of the continuously variable transmission 1, thereby improving productivity.

[0070] More specifically, the preload applying member 52 is disposed between the left end of the outer ring 50a of the ball bearing 50 and a disk-shaped preload applying member holder 43B that is continuous with the right end of the bearing holder 43A of the transmission case 41. The restoring force of the preload applying member 52 presses the output shaft 3 rightward via the ball bearing 50. As a result, a leftward force acts on the outer ring 51a of the tapered roller bearing 51, and this force acts as a preload on the tapered roller bearing 51. In addition, because the preload applying member 52 biases the transmission case 41 leftward, it prevents the transmission case 41 from being displaced in the axial direction due to a leftward load, thereby suppressing the generation of noise and vibration due to displacement of the transmission case 41.

[0071] Furthermore, when the preload applying member 52 is constructed from a diaphragm spring, by designing the preload applying member 52 so that the preload applied to the tapered roller bearing 51 has a convex load characteristic, it is possible to apply a stable preload to the tapered roller bearing 51 even if there is variation in the axial positional tolerance of the ball bearing 50.

[0072] Next, the operation of the continuously variable transmission 1 will be described. The rotational power of the driving force source 10 is transmitted to the input shaft 2 of the continuously variable transmission 1, and then transmitted from the sun roller 2A, which is integral with the input shaft 2, to the input planetary cone 14. Because a ball cam mechanism 21 is provided between the input planetary cone 14 and the output planetary cone 15, the rotational power of the driving force source 10 is transmitted from the input planetary cone 14 to the output planetary cone 15 via the sphere 20, and then the rotational power is transmitted from the output planetary cone 15 to the ring roller 6. In other words, the rotation of the sun roller 2A causes the planetary cone 5 to rotate together with the support shaft 16, and the rotational power of the planetary cone 5 is transmitted to the ring roller 6.

[0073] When the rotational power is transmitted from the output side planetary cone 15 to the ring roller 6, the rotational power is transmitted from the output shaft 3 via the final drive gear to the final driven gear of the differential device, and then from the differential device to the left and right drive wheels via the left and right drive shafts.

[0074] In the continuously variable transmission 1, rotational force (driving force) is transmitted and simultaneously speed change (conversion of rotational speed) is performed as follows: The rotational speed of the sun roller 2A is transmitted to the input side planetary cone 14, and the planetary cone 5 rotates at a rotational speed that is changed in accordance with the ratio between the radius of the sun roller 2A and the radius of the contact point on the input side planetary cone 14. The rotational speed of the planetary cone 5 is transmitted to the ring roller 6. At this time, the ring roller 6 rotates at a rotational speed that is changed in accordance with the ratio between the radius of the ring roller 6 and the radius of the contact point on the planetary cone 5.

[0075] For example, when the planetary cone 5 is moved by the movement mechanism 30 to a position farthest from the shaft portion 3A of the output shaft 3 (the rightmost position within the movable range of the planetary cone 5), the sun roller 2A comes into contact with the smallest diameter conical surface 14d of the input side planetary cone 14, as shown in FIG. 1. At this time, the ring roller 6 comes into contact with the largest diameter conical surface 15d on the bottom surface 15b side of the output side planetary cone 15. As a result, the rotational speed of the sun roller 2A is increased by the planetary cone 5 and transmitted to the ring roller 6. This is the state in which the gear ratio of the continuously variable transmission 1 is smallest.

[0076] On the other hand, when the planetary cone 5 is moved by the movement mechanism 30 to the position closest to the shaft portion 3A of the output shaft 3 (the leftmost position within the movable range of the carrier 4), the sun roller 2A comes into contact with the largest-diameter conical surface 14d on the bottom surface 14b side of the input-side planetary cone 14, as shown in FIG. 3. At this time, the ring roller 6 comes into contact with the smallest-diameter conical surface 15d of the output-side planetary cone 15. As a result, the rotational speed of the sun roller 2A is reduced by the planetary cone 5 and transmitted to the ring roller 6. This is the state in which the gear ratio of the continuously variable transmission 1 is greatest.

[0077] In other words, the continuously variable transmission 1 is capable of continuously changing the rotational speed (rotational power) of the input shaft 2 to the output shaft 3 via the planetary cones 5 by changing the contact position P1 between the conical surface 14d of the input side planetary cone 14 and the sun roller 2A, and the contact position P2 between the conical surface 15d of the output side planetary cone 15 and the ring roller 6 using the carrier 4.

[0078] While the planetary cone 5 is being moved by the movement mechanism 30, the planetary cone 5 temporarily changes its posture and becomes skewed. However, due to the oscillation of the guide roller 35 in the groove 34A of the shift drum 34, the action of the self-aligning bearing 17, and the driving force that suppresses the tilt so that the skew angle is minimized, the carrier 4 moves axially on the shift flange 32. As a result, the planetary cone 5 automatically returns to the position where the skew angle is minimized. Specifically, as shown in FIG. 4, the position of the line forming the contact surface between the planetary cone 5 and the ring roller temporarily shifts from position L1 when the planetary cone 5 is not tilted to position L2 when the planetary cone 5 is tilted. Furthermore, when the planetary cone 5 is not tilted, a normal force F1 acts on the planetary cone 5 in the circumferential direction of the input shaft 2 (see FIG. 1). When the planetary cone 5 is tilted, a normal force F2 including a component force F3 in the axial direction of the input shaft 2 (see FIG. 1) acts on the planetary cone 5. Then, the component force F3 of the normal force F2 during tilting acts to cancel the tilt of the planetary cone 5, moving the planetary cone 5 and the carrier 4 in the axial direction of the input shaft 2 (to the left in Figure 4), thereby canceling the tilt.

[0079] An oil film of traction oil (not shown) is formed at a contact position P1 between the sun roller 2A and the conical surface 14d of the input planetary cone 14, and at a contact position P2 between the ring roller 6 and the conical surface 15d of the output planetary cone 15. This allows power to be transmitted from the sun roller 2A to the input planetary cone 14 via the oil film, and from the ring roller 6 to the output planetary cone 15 via the oil film.

[0080] The input side planetary cone 14 is disposed so that its conical surface 14d extends parallel to the axis 2r of the input shaft 2 and is in constant contact with the sun roller 2A. The output side planetary cone 15 is disposed so that its conical surface 15d extends parallel to the axis 2r of the input shaft 2 and is in constant contact with the ring roller 6.

[0081] This allows the planetary cone 5 to move parallel to the conical surfaces 14d and 15d relative to the sun roller 2A and ring roller 6 during gear shifting, preventing excessive friction between the sun roller 2A and conical surface 14d and between the ring roller 6 and conical surface 15d, thereby enabling smooth gear shifting.

[0082] Since the input planetary cone 14 and the output planetary cone 15 have the same shape, having the same outer diameter and groove shape, when the torque input to the input planetary cone 14 is small, the sphere 20 is located at the deepest position in the circumferential center of the input cam groove 14f and the output cam groove 15f of the input planetary cone 14. In other words, the input planetary cone 14 and the output planetary cone 15 are located closest to each other.

[0083] In this case, the input planetary cone 14 and the output planetary cone 15 rotate together. In this state, torque is transmitted from the input planetary cone 14 to the output planetary cone 15 via the sphere 20.

[0084] This state is under light load, and the contact pressure between the conical surface 14d of the input planetary cone 14 and the sun roller 2A, and the contact pressure between the conical surface 15d of the output planetary cone 15 and the ring roller 6 are adjusted to an appropriate level that does not cause slippage. This is largely due to the elastic member 5A.

[0085] On the other hand, when the torque input to the input planetary cone 14 increases (i.e., when the output planetary cone 15 becomes difficult to rotate relative to the rotation of the input planetary cone 14), the output planetary cone 15 begins to lag behind the input planetary cone 14. In other words, the entire planetary cone 5 enters a twisted state. In other words, the output planetary cone 15 cannot follow the rotation of the input planetary cone 14, and the input planetary cone 14 shifts relative to the output planetary cone 15 in the rotational direction.

[0086] Power is transmitted between the input side planetary cone 14 and the output side planetary cone 15 via the sphere 20, but this relative misalignment causes the sphere 20 to move from the deep part (the center in the circumferential direction) of the input side cam groove 14f and the output side cam groove 15f to the shallow part (one side in the circumferential direction), causing the input side planetary cone 14 and the output side planetary cone 15 to move apart in the axial direction of the support shaft 16.

[0087] This is because the input side cam groove 14f and the output side cam groove 15f act like cam slopes with respect to the sphere 20, generating a repulsive force and movement according to torque like a torque cam.

[0088] As a result, the input side planetary cone 14 and the output side planetary cone 15 move in directions away from each other on the support shaft 16 .

[0089] Therefore, the contact pressure between the conical surface 14d of the input side planetary cone 14 and the sun roller 2A, and the contact pressure between the conical surface 15d of the output side planetary cone 15 and the ring roller 6 increase according to the torque (input load) transmitted by the planetary cone 5.

[0090] In addition, the shape of the change in groove depth in input side cam groove 14f and output side cam groove 15f does not have to be a simple inclination angle, but the inclination may be changed so that it becomes larger as you move from the circumferential center of input side cam groove 14f and output side cam groove 15f to the circumferential end.

[0091] Since the sphere 20 is located at the circumferential center of the input side cam groove 14f and the output side cam groove 15f, when the input side planetary cone 14 is twisted in the opposite direction to the rotation direction described above relative to the output side planetary cone 15, the sphere 20 can be moved from the circumferential center of the input side cam groove 14f and the output side cam groove 15f in the opposite direction to the above-mentioned direction, thereby separating the input side planetary cone 14 and the output side planetary cone 15 in the axial direction of the support shaft 16.

[0092] Next, the effects of the continuously variable transmission 1 of this embodiment will be described.

[0093] In the continuously variable transmission 1 of this embodiment, the contact position P1 between the conical surface 14d of the planetary cone 5 and the sun roller 2A and the contact position P2 between the conical surface 15d of the planetary cone 5 and the ring roller 6 are at the same position in the axial direction of the input shaft 2.

[0094] This makes it possible to prevent the normal force acting on the conical surfaces 14d, 15d of the planetary cone 5 from generating a rotational moment on the self-aligning bearings 17 and bearings 54 at both ends of the support shaft 16 that rotates the support shaft 16 toward the inside or outside in the radial direction of the input shaft 2. Therefore, it is possible to prevent the durability of the self-aligning bearings 17 and bearings 54 from being reduced due to the rotational moment acting on the support shaft 16.

[0095] Furthermore, since the contact position of the planetary cone 5 with the sun roller 2A and the ring roller 6 can be changed without applying a rotational moment to the support shaft 16, the planetary cone 5 can be moved in the axial direction of the input shaft 2 with a small operating force on the movement mechanism 30, and the gear ratio can be changed by moving the planetary cone 5 in the axial direction of the input shaft 2 without reducing power transmission efficiency due to the generation of excessive normal force.

[0096] As a result, it is possible to prevent a decrease in the durability of the self-aligning bearing 17 and the bearing 54 that support the planetary cone 5, and to prevent a decrease in power transmission efficiency.

[0097] In the continuously variable transmission 1 of this embodiment, a contact position P1 between the conical surface 14d of the planetary cone 5 and the sun roller 2A, and a contact position P2 between the conical surface 15d of the planetary cone 5 and the ring roller 6 extend substantially parallel to the input shaft 2.

[0098] As a result, even if the planetary cone 5 moves in the axial direction, the contact pressure with the sun roller 2A and the ring roller 6 does not change, so when performing a gear change operation to change the gear ratio, the planetary cone 5 can be moved smoothly in the axial direction of the input shaft 2 with a small operating force, making it possible to easily change the gear ratio.

[0099] In the continuously variable transmission 1 of this embodiment, the planetary cone 5 has an input side planetary cone 14 with which the sun roller 2A comes into contact, an output side planetary cone 15 that is provided separately from the input side planetary cone 14 and with which the ring roller 6 comes into contact, and an elastic member 5A that is provided in a compressed state between the bottom surface 14b of the input side planetary cone 14 and the bottom surface 15b of the output side planetary cone 15.

[0100] This allows the dimensional tolerances to be set so as to provide a gap at the contact position P1 between the conical surface 14d of the input-side planetary cone 14 of the planetary cone 5 and the sun roller 2A, and also so as to provide a gap at the contact position P2 between the conical surface 15d of the output-side planetary cone 15 of the planetary cone 5 and the ring roller 6. The elastic member 5A can then be assembled to the transmission case 41 in a compressed state. This improves the ease of assembly of the planetary cone 5.

[0101] Furthermore, by providing the elastic member 5A in a compressed state between the input planetary cone 14 and the output planetary cone 15, the restoring force of the elastic member 5A allows the conical surface 14d of the input planetary cone 14 to be constantly in contact with the sun roller 2A to transmit torque, and the conical surface 15d of the output planetary cone 15 to be constantly in contact with the ring roller 6 to transmit torque. Furthermore, even if gaps occur between the conical surface 14d of the input planetary cone 14 and the sun roller 2A and between the conical surface 15d of the output planetary cone 15 and the ring roller 6 due to manufacturing tolerances or centrifugal force during rotation, the restoring force of the elastic member 5A can eliminate these gaps.

[0102] In the continuously variable transmission 1 of this embodiment, the planetary cone 5 has a ball cam mechanism 21 that connects the bottom surface 14b of the input planetary cone 14 with the bottom surface 15b of the output planetary cone 15 to transmit power from the input planetary cone 14 to the output planetary cone 15. The ball cam mechanism 21 has an input cam groove 14f formed in the bottom surface 14b of the input planetary cone 14, an output cam groove 15f formed in the bottom surface 15b of the output planetary cone 15, and spheres 20 accommodated in the input cam groove 14f and the output cam groove 15f. The input cam groove 14f and the output cam groove 15f extend in the circumferential direction about the axis 16r of the support shaft 16, and are formed shallower toward the ends in the circumferential direction.

[0103] With regard to this ball cam mechanism 21, when the driver of the vehicle operates the accelerator, a difference occurs between the torques acting on the input side planetary cone 14 and the output side planetary cone 15, causing a deviation in the rotational direction between the input side planetary cone 14 and the output side planetary cone 15, and so the sphere 20 moves within the gap between the input side cam groove 14f and the output side cam groove 15f. As a result, the sphere 20 pushes open the gap between the input side planetary cone 14 and the output side planetary cone 15, generating an appropriate normal force (pressing force) according to the input torque between the input side planetary cone 14 and the sun roller 2A, and between the output side planetary cone 15 and the ring roller 6, allowing for appropriate torque transmission.

[0104] The continuously variable transmission 1 of this embodiment comprises: a ball bearing 50 having an outer ring 50a fitted to the transmission case 41; an inner ring 50c connected to the outer ring 50a via rolling elements 50b and fitted to the outer peripheral surface of the output shaft 3; a tapered roller bearing 51 having an outer ring 51a fitted to the inner peripheral surface of the output shaft 3; and an inner ring 51c connected to the outer ring 51a via roller-shaped rolling elements 51b and fitted to the outer peripheral surface of the input shaft 2; and a preload applying member 52 that is provided in a compressed state between the ball bearing 50 and the transmission case 41 and urges the ball bearing 50 in the axial direction of the input shaft 2 so as to apply a preload to the tapered roller bearing 51.

[0105] As a result, by using the tapered roller bearing 51 and adjusting the preload of the tapered roller bearing 51 using the ball bearing 50 and the preload applying member 52, it is possible to prevent the input shaft 2 and the output shaft 3 from shifting in the axial or radial direction.

[0106] Furthermore, when a load is applied by ball cam mechanism 21 in a direction that moves bottom surface 14b of input planetary cone 14 and bottom surface 15b of output planetary cone 15 apart, a component force in the axial direction of planetary cone 5 is generated on sun roller 2A and ring roller 6. This component force generates an axial load on tapered roller bearing 51, thereby improving the support rigidity of tapered roller bearing 51 for input shaft 2 and output shaft 3. In addition, the increased support rigidity holds input shaft 2 and output shaft 3 coaxially, reducing rotational noise from planetary cone 5 and reducing rolling loss due to the parallel rotational directions of sun roller 2A and ring roller 6.

[0107] Furthermore, if a preload were applied directly to the outer ring 51a of the tapered roller bearing 51, the relative position between the sun roller 2A and the ring roller 6 would change due to the component of the reaction force of the ball cam mechanism 21 that occurs when the transmission torque is turned on and off. However, in this embodiment, a preload is always applied to the tapered roller bearing 51 by the transmission case 41 via the ball bearing 50 that supports the output shaft 3, so that the relative position between the sun roller 2A and the ring roller 6 can be prevented from changing due to the component of the force from the ball cam mechanism 21 of the planetary cone 5.

[0108] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0109] 1...Continuously variable transmission, 2...Input shaft, 2A...Sun roller (input member), 3...Output shaft, 5...Planetary cone, 5A...Elastic member, 6...Ring roller (output member), 10...Driving force source, 14...Input side planetary cone, 14b...Bottom surface, 14d...Conical surface, 14f...Input side cam groove, 15...Output side planetary cone, 15b...Bottom surface, 15d...Conical surface, 15f...Output side cam groove, 16...Support shaft, 1 6r...shaft center, 17...self-aligning bearing, 20...sphere, 21...ball cam mechanism, 30...movement mechanism, 31...speed change operating part, 41...transmission case, 50...ball bearing, 50a...outer ring, 50b...rolling element, 50c...inner ring, 51...taper roller bearing, 51a...outer ring, 51b...rolling element, 51c...inner ring, 52...preload applying member, 54...bearing, P1, P2...contact position

Claims

1. an input member attached to an input shaft to which rotational power is input from a driving power source; an output member that transmits the rotational power input from the input member to an output shaft; a planetary cone having a conical surface with which the input member and the output member come into contact and formed in a truncated cone shape; a support shaft that supports the planetary cone rotatably and movably in its axial direction; a movement mechanism that changes a contact position of the input member on the conical surface of the planetary cone and a contact position of the output member on the conical surface of the planetary cone, a contact position between the conical surface of the planetary cone and the input member and a contact position between the conical surface of the planetary cone and the output member are located at the same position in the axial direction of the input shaft, a ball bearing having an outer ring fitted to a transmission case and an inner ring connected to the outer ring via rolling elements and fitted to an outer peripheral surface of the output shaft; a tapered roller bearing including an outer ring fitted to the inner peripheral surface of the output shaft, and an inner ring connected to the outer ring via roller-shaped rolling elements and fitted to the outer peripheral surface of the input shaft; a preload applying member that is provided in a compressed state between the outer ring of the ball bearing and the transmission case, and that urges the ball bearing in the axial direction of the input shaft so as to apply a preload to the tapered roller bearing.

2. 2. The continuously variable transmission according to claim 1, wherein a contact position of the conical surface of the planetary cone with the input member and a contact position of the conical surface of the planetary cone with the output member each extend substantially parallel to the input shaft.

3. The planetary cone is an input side planetary cone with which the input member comes into contact; an output side planetary cone provided separately from the input side planetary cone and in contact with the output member; 3. The continuously variable transmission according to claim 1, further comprising: an elastic member provided in a compressed state between the bottom surface of the input planetary cone and the bottom surface of the output planetary cone.

4. the planetary cone has a ball cam mechanism that connects a bottom surface of the input side planetary cone with a bottom surface of the output side planetary cone to transmit power from the input side planetary cone to the output side planetary cone, The ball cam mechanism an input side cam groove formed on the bottom surface of the input side planetary cone; an output side cam groove formed on the bottom surface of the output side planetary cone; a sphere housed in the input-side cam groove and the output-side cam groove, the input-side cam groove and the output-side cam groove extend in a circumferential direction around the axis of the support shaft, 4. The continuously variable transmission according to claim 3, wherein the input cam groove and the output cam groove are formed so that their circumferential ends are shallower.

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