Toroidal type continuously variable transmission

Abstract

To provide a toroidal type continuously variable transmission capable of regulating a radial displacement of a disc.SOLUTION: In a toroidal type continuously variable transmission, a restriction member 70 that restricts radial displacement of at least one of an input side disc 2 and an output side disc 3 is supported on a casing 50 side. The regulation member 70 allows axial movement of the input side disc 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toroidal type continuously variable transmission used in automobiles, aircraft, etc. [Background technology]

[0002] Double-cavity toroidal continuously variable transmissions are commonly known as transmissions used in automobiles, for example. This double-cavity toroidal continuously variable transmission is configured, for example, as shown in FIGS. 8 and 9. That is, as shown in FIG. 8, an input shaft 1 is rotatably supported inside a casing 50, and two input discs 2, 2 and two output discs 3, 3 are attached to the outer periphery of this input shaft 1. An output gear 4 is rotatably supported on the outer periphery of a middle portion of the input shaft 1. The output discs 3, 3 are spline-connected to cylindrical flanges 4a, 4a provided at the center of this output gear 4.

[0003] The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between the input side disc 2 located on the left side of the drawing and a cam plate (loading cam) 7. The output gear 4 is supported within a casing 50 via an intermediate wall 13 formed by joining two members, which allows the input shaft 1 to rotate around the axis O while preventing displacement in the direction of the axis O.

[0004] As shown in FIG. 8, the output-side discs 3 are supported rotatably about the axis O of the input shaft 1 by needle bearings 5 ​​interposed between them and the input shaft 1. The input-side disc 2 on the left side of the drawing is supported on the input shaft 1 via a ball spline 6, and the input-side disc 2 on the right side of the drawing is spline-connected to the input shaft 1, so that these input-side discs 2 rotate together with the input shaft 1. Power rollers 11 (see FIG. 9) are rotatably sandwiched between inner surfaces (concave surfaces; also called traction surfaces) 2a of the input-side discs 2 and inner surfaces (concave surfaces; also called traction surfaces) 3a of the output-side discs 3.

[0005] A stepped portion 2b is provided on the inner peripheral surface 2c of the input side disc 2 located on the right side in Fig. 8, and a stepped portion 1b provided on the outer peripheral surface 1a of the input shaft 1 abuts against this stepped portion 2b, while the back surface of the input side disc 2 (the right surface in Fig. 8) abuts against a loading nut 9 that is screwed onto a threaded portion formed on the outer peripheral surface of the input shaft 1. This substantially prevents displacement of the input side disc 2 in the direction of the axis O relative to the input shaft 1. In addition, a disc spring 8 is provided between the cam plate 7 and the flange portion 1d of the input shaft 1, and this disc spring 8 applies a pressing force (preload) to the contact portions between the concave surfaces 2a, 2a, 3a, 3a of the discs 2, 2, 3, 3 and the peripheral surfaces 11a, 11a of the power rollers 11, 11.

[0006] FIG. 9 is a cross-sectional view taken along line AA in FIG. 8. As shown in FIG. 9, a pair of trunnions 15, 15 are provided inside the casing 50. The pair of trunnions 15 swing around a pair of pivots 14, 14 that are twisted relative to the input shaft 1. Note that the input shaft 1 is not shown in FIG. 9. Each trunnion 15, 15 has a pair of bent wall portions 20, 20 at both ends of the support plate portion 16 in the longitudinal direction (the vertical direction in FIG. 9), which are bent toward the inner surface of the support plate portion 16. The bent wall portions 20, 20 form a recessed pocket P in each trunnion 15, 15 for accommodating the power roller 11. The pivots 14, 14 are provided concentrically on the outer surfaces of the bent wall portions 20, 20.

[0007] A circular hole 21 is formed in the center of the support plate 16, and this circular hole 21 supports a support shaft portion 23a forming the base end of a displacement shaft (pivot shaft) 23. The inclination angle of the displacement shaft 23 supported in the center of each trunnion 15 can be adjusted by swinging each trunnion 15 about each pivot shaft 14. Each power roller 11 is rotatably supported around a pivot shaft portion 23b forming the tip end of the displacement shaft 23 protruding from the inner surface of each trunnion 15 via a radial needle bearing (a cage-and-roller bearing that bears a radial load) 35 that bears a pressing load acting on the inner ring (power roller 11) of a thrust ball bearing 24 (described later). Each power roller 11 is sandwiched between each input-side disc 2 and each output-side disc 3. The support shaft portion 23a and the pivot shaft portion 23b of each displacement shaft 23, 23 are eccentric to each other.

[0008] The pivots 14 of each trunnion 15 are supported by a pair of yokes 23A and 23B so as to be swingable and displaceable in the axial direction (vertical direction in FIG. 9), and the horizontal movement of the trunnions 15 is restricted by the yokes 23A and 23B. Each yoke 23A and 23B is formed into a rectangular shape by pressing or forging a metal such as steel. Four circular support holes 18 are formed in the four corners of each yoke 23A and 23B, and the pivots 14 provided at both ends of the trunnion 15 are supported in these support holes 18 via radial needle bearings 30 so as to be swingable. A circular locking hole 19 is formed in the center of the yokes 23A and 23B in the width direction (horizontal direction in FIG. 9), and the inner circumferential surface of this locking hole 19 is cylindrical, and spherical posts 64 and 68 are fitted into it. That is, the upper yoke 23A is supported so as to be freely swingable by a spherical post 64 which is supported on the casing 50 via a fixed member 52, and the lower yoke 23B is supported so as to be freely swingable by a spherical post 68 and the upper cylinder body 61 of the drive cylinder (cylinder body) 31 which supports it.

[0009] The displacement shafts 23, 23 provided on each trunnion 15, 15 are located at positions 180 degrees opposite each other with respect to the input shaft 1. The direction in which the pivot shaft portions 23b of each of these displacement shafts 23, 23 are eccentric with respect to the support shaft portions 23a is the same as the direction of rotation of both disks 2, 2, 3, 3 (opposite directions in FIG. 9). The eccentric direction is also approximately perpendicular to the direction in which the input shaft 1 is disposed. Therefore, each power roller 11, 11 is supported so as to be able to displace slightly in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to displace in the axial direction of the input shaft 1 due to elastic deformation of each component due to the thrust load generated by the loading cam-type pressing device 12, this displacement is absorbed without applying excessive force to each component.

[0010] Between the outer surface (large end surface) 11b of the power roller 11 and the inner surface 16a of the support plate portion 16 of the trunnion 15, in this order from the outer surface 11b side of the power roller 11, there are provided thrust ball bearings (thrust bearings) 24, which are thrust rolling bearings, and thrust needle bearings 25. Of these, the thrust ball bearings 24 support the thrust load applied to each power roller 11 while allowing each power roller 11 to rotate. Each thrust ball bearing 24 is composed of a plurality of balls (rolling elements) 26, 26, an annular cage 27 that holds each of the rolling elements 26, 26 in a rollable manner, and an annular outer ring 28. The inner ring raceway surface 24a of each thrust ball bearing 24 is formed on the outer surface 11b of the power roller 11, and the outer ring raceway surface 24b is formed on the inner surface of the outer ring 28.

[0011] The thrust needle bearings 25 are sandwiched between the inner surface 16a of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. Such thrust needle bearings 25 support the thrust load applied from the power rollers 11 to the outer rings 28, while allowing the power rollers 11 and the outer rings 28 to swing around the support shaft portions 23a of the displacement shafts 23.

[0012] Furthermore, a drive rod (trunnion shaft) 29 is provided at one end (lower end in FIG. 9) of each trunnion 15, and a drive piston (hydraulic piston) 33 is fixed to the outer circumferential surface of the middle portion of each drive rod 29. Each of these drive pistons 33 is oil-tightly fitted into a drive cylinder 31 formed by an upper cylinder body 61 and a lower cylinder body 62. Each of these drive pistons 33 and drive cylinder 31 constitutes a drive unit 32 that displaces each of the trunnions 15 in the axial direction of the pivots 14 of the trunnions 15.

[0013] In the case of a toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input side discs 2, 2 via a loading cam type pressing device 12. The rotation of these input side discs 2, 2 is then transmitted to the output side discs 3, 3 via a pair of power rollers 11, 11, and the rotation of these output side discs 3, 3 is further extracted by the output gear 4.

[0014] To change the rotational speed ratio between the input shaft 1 and the output gear 4, the pair of drive pistons 33, 33 are displaced in opposite directions. As the drive pistons 33, 33 are displaced, the pair of trunnions 15, 15 are displaced in opposite directions. For example, the power roller 11 on the left side of FIG. 9 is displaced downward, and the power roller 11 on the right side of FIG. 9 is displaced upward.

[0015] As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 11a, 11a of the power rollers 11, 11 and the inner surfaces 2a, 2a, 3a, 3a of the input side discs 2, 2 and the output side discs 3, 3 changes. Then, with this change in the direction of the force, the trunnions 15, 15 swing (tilt) in opposite directions to each other around the pivots 14, 14 pivotally supported by the yokes 23A, 23B.

[0016] As a result, the contact position between the peripheral surfaces 11a, 11a of each power roller 11, 11 and the inner surfaces 2a, 3a changes, changing the rotational speed ratio between the input shaft 1 and the output gear 4. Furthermore, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11, 11 and the outer rings 28, 28 attached to each power roller 11, 11 rotate slightly around the support shaft portions 23a, 23a of the displacement shafts 23, 23. The presence of thrust needle bearings 25, 25 between the outer surfaces of the outer rings 28, 28 and the inner surfaces of the support plates 16 that constitute the trunnions 15, 15, respectively, ensures smooth rotation. Therefore, as described above, only a small force is required to change the inclination angle of each displacement shaft 23, 23.

[0017] Conventionally, a gap that allows axial movement of the variator is provided between the bearings (or sliding members) that support the variator so that the variator (a continuously variable transmission mechanism including the input shaft 1, discs 2 and 3, and power rollers 11) having the above-described configuration incorporated in the casing 50 can move axially during operation by the above-described loading cam-type pressing device 12, which is a loading mechanism that generates axial force for traction drive. Specifically, as shown in Fig. 10, a radial gap s1 that allows the variator to move axially during operation of the pressing device 12 and the bearings (or sliding members) 90 of the various parts that support the variator, and a radial gap s2 that prevents the radial gap s1 from decreasing due to deformation of the discs 2 and 3 (preventing the gap from becoming negative).

[0018] 10, the pressing device 12 that generates the axial force for traction drive is composed of the aforementioned cam plate (loading cam) 7 that rotates together with the input shaft 1, and multiple (e.g., four) rollers (rolling elements) 12b that are rollably held by a cage 12a between the cam plate 7 and the input side disc 2 (the input side disc 2 on the right side in FIG. 10). The pressing device elastically presses the input side disc 2 toward the output side disc 4, allowing the input side disc 2 to rotate freely. A cam surface 113 with circumferential irregularities is formed on one side of the cam plate 7 (the left side in FIG. 10), and a cam surface 114 with a similar shape is formed on the outer surface of the input side disc 2 (the right side in FIG. 10). An angular inner ring raceway 115 is formed on one side of the aforementioned flange-like collar portion 1d at the end of the input shaft 1. A plurality of balls 118 are interposed between this inner ring raceway 115 and an angular outer ring raceway 117 formed on the inner peripheral surface of a bearing support member (outer ring) 116. In other words, the flange 1d, bearing support member 116, and balls 118 constitute an angular ball bearing 120 that can freely support thrust loads.

[0019] Furthermore, in relation to the aforementioned axial movement of the variator caused by such a pressing device 12, for example, Patent Document 1 discloses a technology in which thrust angular bearings are arranged on both axial end surfaces of the output side disc, and the axial movement of the output side disc is restricted, thereby improving rigidity and enabling an expansion of the traction surface. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-174573 Summary of the Invention [Problem to be solved by the invention]

[0021] In recent years, toroidal-type continuously variable transmissions (CVTs) have been required to achieve lighter weight, increased power generation capacity, and higher speeds due to a wider gear range, in response to the increasing performance of aircraft, automobiles, and other equipment equipped with them. Accordingly, the input shaft 1 of the variator has become thinner due to the weight reduction, and its axial length has increased due to an increase in the number of variator parts, making it more susceptible to bending deformation. When the input shaft 1 becomes more susceptible to deformation, the radial displacement D (indicated by the arrow in FIG. 10 ) of the discs 2 and 3 may increase due to imbalances in the discs 2 and 3 and the pressing device 12. Furthermore, the centrifugal force generated by the rotation of the input shaft 1 may increase the radial displacement D of the discs 2 and 3. If the radial displacement D of the discs 2 and 3 is large, the tilting motions of the power rollers in traction contact with the discs 2 and 3 may become asynchronized (asynchronized offset amounts of the trunnions), resulting in a decrease in transmitted power or, in the worst case, the inability to transmit power.

[0022] As mentioned above, the variator is supported by bearings (or sliding members) 90 arranged on the discs 2, 3 and the input shaft 1, and moves axially due to loading by the pressing device 12. Therefore, radial gaps s1, s2 must be provided between the bearings 90 and the variator to allow for such movement. However, in the past, the rigidity of the input shaft 1 was high and deformation of the input shaft 1 was almost negligible, so it was possible to accommodate radial displacement D of the discs 2, 3 simply by managing the radial gaps s1, s2. However, for the reasons described above, if the deformation of the input shaft 1 becomes large enough to be non-negligible and is combined with the radial clearances s1 and s2, the radial displacement D of the disks 2 and 3 becomes large, and it becomes difficult to regulate the radial displacement D of the disks 2 and 3 simply by controlling the radial clearances s1 and s2. In particular, as shown in FIG. 10 , in the case of the right input side disk 2, which cannot be directly supported by the bearing (or sliding member) 90 due to the presence of the pressing device 12, the radial displacement D cannot be sufficiently regulated, coupled with the imbalance in the pressing device 12. Furthermore, the centrifugal force generated by the rotation of the input shaft 1 may make it difficult to regulate the radial displacement D of the disks 2 and 3.

[0023] The present invention has been made in view of the above circumstances, and has as its object to provide a toroidal type continuously variable transmission that can restrict radial displacement of the disc. [Means for solving the problem]

[0024] In order to achieve the above object, the present invention provides a toroidal type continuously variable transmission comprising an input shaft, an input side disc and an output side disc arranged concentrically with the input shaft and freely rotatable relative to each other with their inner surfaces facing each other, a power roller held between the input side disc and the output side disc, and a pressing device arranged on an outer surface of the input side disc or the output side disc opposite to the inner surface of the input side disc or the output side disc and pressing the input side disc or the output side disc in the axial direction so as to bring the input side disc and the output side disc closer to each other, which are assembled in a casing, A restricting portion for restricting radial displacement of at least one of the input side disc or the output side disc is provided on the casing side.

[0025] According to the above configuration, a restricting portion that restricts radial displacement of at least one of the input disc or the output disc (hereinafter, sometimes collectively referred to simply as the disc) is provided on the casing, so even if the disc attempts to displace radially due to imbalance in the disc or the pressing device, such displacement is restricted by the restricting portion. This prevents the variator from becoming out of sync, reducing transmitted power, or making power transmission impossible.

[0026] In the above configuration, the restricting portion may be present in any form as long as it can restrict radial displacement of at least one of the input disc or the output disc. For example, it may be formed by the casing itself, for example, by abutting the disc against the casing in the radial direction (preferably through sliding contact that allows axial sliding). Alternatively, it may be configured as a restricting member supported on the casing. If configured as a restricting member, such a restricting member may be supported on the casing and located at any position on the components of the variator. Furthermore, the restricting portion may be provided for one or both of the input disc and the output disc. In a variator having multiple input discs and multiple output discs, such as a double-cavity type, the restricting portion may be provided for at least one of the input discs (in the case of an input disc, a disc with or without a pressing device on its outer surface) or all of the input discs. Furthermore, in the above configuration, the pressing device may be a loading cam type or a hydraulic type.

[0027] Furthermore, it is preferable that the restricting portion allows axial movement of at least one of the input disc or the output disc. This allows the disc to move axially without hindrance when operated by a pressing device that generates an axial force for traction drive. When the restricting portion is a restricting member that allows axial movement of the disc, examples of such a restricting member include a cylindrical roller bearing, a ball bearing, and a sliding bearing.

[0028] In the above configuration, the regulating portion preferably regulates radial displacement of the input side disc or the output side disc associated with the pressing device on its outer surface. As described above with reference to Figure 10, an input side disc or an output side disc associated with the pressing device on its outer surface generally cannot be directly supported by a bearing (or a sliding member) (the bearing supports the input side disc or the output side disc at a position distant from the input side disc or the output side disc), and therefore radial displacement of the input side disc or the output side disc due to imbalance may not be sufficiently regulated. However, by providing a regulating portion as in this configuration, radial displacement of the input side disc or the output side disc can be sufficiently regulated.

[0029] In the above configuration, the regulating member as the regulating portion is preferably interposed between the casing and the outer peripheral surface of the input or output disc, the outer surface of which includes the pressing device. This allows the regulating member to be positioned stably and efficiently using space, and effectively restricts radial displacement of the input or output disc. In this case, the regulating member may include, for example, multiple rollers that contact the outer peripheral surface of the input or output disc to support the input or output disc in the radial direction, and biasing members that are interposed between the casing and each roller and bias the roller in a direction that brings the roller into contact with the outer peripheral surface of the input or output disc. This type of regulating member allows the input or output disc to be stably supported in the radial direction from multiple directions, and allows axial movement of the input or output disc by resisting the biasing forces of the biasing members.

[0030] In a configuration in which the regulating member is interposed between the outer peripheral surface of an input-side or output-side disc having a pressing device on its outer surface and the casing, the regulating member may be formed as a deep groove ball bearing. In this case, the deep groove ball bearing may have an outer ring member and rolling elements supported for free movement between an outer ring raceway of the outer ring member and an inner ring raceway formed on the outer peripheral surface of the input-side or output-side disc, and a radial gap that allows axial movement of the input-side or output-side disc may be provided between the outer ring member and the casing. With this type of regulating member, the deep groove ball bearing can stably support the input-side or output-side disc in the radial direction over the entire circumference, and the radial gap provided between the outer ring member and the casing allows axial movement of the input-side or output-side disc.

[0031] In a configuration in which the regulating member is interposed between the outer peripheral surface of an input or output disc having a pressing device on its outer surface and the casing, the regulating member may be formed as an angular contact ball bearing. In this case, the angular contact ball bearing has an outer ring member and rolling elements supported for free movement between an outer ring raceway of the outer ring member and an inner ring raceway formed over the outer and outer surfaces of the input or output disc, a radial gap that allows axial movement of the input or output disc may be provided between the outer ring member and the casing, and a biasing member that applies a preload in the axial direction from the outer surface of the input or output disc to the inner surface may be provided between the outer ring member and the casing. With this type of regulating member, the input or output disc can be stably supported radially over the entire circumference by the angular contact ball bearing, and the radial gap provided between the outer ring member and the casing allows axial movement of the input or output disc. Furthermore, since the biasing member applies an axial preload from the outer surface of the input or output disc to the inner surface, it is possible to apply a preload to compensate for axial movement of the input or output disc, and it is also possible to suppress axial deformation of the outer periphery of the input disc due to the normal force of the power rollers. Note that the preload applied by the biasing member is preferably a constant preload, and is preferably a preload load that does not cause preload loss or excessive preload during axial movement of the input or output disc.

[0032] In the above configuration, if the pressing device is a loading cam type pressing device including a cam plate that rotates with the input shaft and rolling elements that are held by a cage so as to be rollable between the cam plate and the outer surface of the input-side disc or the output-side disc, the regulating member may be interposed between the outer peripheral surface of the cage and the casing, or may be interposed between the outer peripheral surface of the cam plate and the casing. In this case, too, the regulating member may be in a form including the above-mentioned roller and a biasing member that biases the roller, or may be formed as the above-mentioned deep groove ball bearing or the above-mentioned angular contact ball bearing. [Effects of the Invention]

[0033] According to the present invention, a regulating member that regulates radial displacement of the disk is supported on the casing side, so that even if the disk attempts to displace radially due to imbalance in the disk or pressing device, such displacement is regulated by the regulating member. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a fourth embodiment of the present invention. [Figure 5] 5 is a schematic view taken in the direction of the arrow A in FIG. 4. [Figure 6] FIG. 10 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a fifth embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view of a main part of a toroidal-type continuously variable transmission according to a sixth embodiment of the present invention. [Figure 8] FIG. 1 is a cross-sectional view showing an example of a conventional toroidal type continuously variable transmission. [Figure 9] FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8. [Figure 10] 10 is a partial half-sectional view showing a specific example of the configuration of a bearing support form and a pressing device of a variator of a conventional toroidal-type continuously variable transmission. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is characterized in that a restricting portion is provided to restrict radial displacement of the disk, and other configurations and functions are the same as those of the conventional configuration and functions described above. Therefore, in the following, only the characteristic parts of the present invention will be mentioned, and other parts will be assigned the same reference numerals as in Figures 8 to 10, and detailed descriptions thereof will be omitted or simplified.

[0036] FIG. 1 shows a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a first embodiment of the present invention. In this embodiment, a restricting member 70 is supported on the casing 50 as a restricting portion for restricting radial displacement of at least one of the input disc 2 or the output disc 3. In particular, in this embodiment, the restricting member 70 restricts radial displacement of the input disc 2 (the input disc on the right side in FIG. 1 ) associated with the pressing device 12 at its outer surface 2b (the surface opposite to the inner surface 2a, which is the traction surface). To this end, the restricting member 70 is interposed between the outer peripheral surface 2c (the radially outer end surface) of the input disc 2 and the casing 50. The restricting member 70 restricts radial displacement of the input disc 2 while allowing axial movement of the input disc 2. Specifically, the restricting member 70 is formed of, for example, a cylindrical roller bearing, a ball bearing, or a sliding bearing.

[0037] In this embodiment, a restricting member 70 may be provided in a similar manner on the output side disc 3 or on the input side disc 2 on the left side in FIG.

[0038] As described above, according to this embodiment, the restricting member 70 that restricts radial displacement of the input side disc 2 is supported on the casing 50 side. Therefore, even if the disc 2 attempts to radially displace due to imbalance in the disc 2 or the pressing device 12 caused by the input shaft 1, which is thin and elongated and therefore prone to bending deformation, such displacement is restricted by the restricting member 70. This prevents situations such as the occurrence of asynchronism in the variator, a decrease in transmitted power, or the impossibility of power transmission. Furthermore, according to this embodiment, the restricting member 70 allows the input side disc 2 to move axially, so that the input side disc 2 can move axially without hindrance when the pressing device 12 operates to generate axial force for traction drive.

[0039] 2 shows a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a second embodiment of the present invention. In this embodiment, a regulating member 70 is interposed between the outer peripheral surface 12aa of the retainer 12a constituting the pressing device 12 and the casing 50. The regulating member 70 serves as a regulating portion that regulates radial displacement of the right input side disc 2 via the pressing device 12 while allowing axial movement of the input side disc 2. In this case, the regulating member 70 regulates radial displacement of the input side disc 2 via the pressing device 12 by the action of frictional force generated between the retainer 12a that holds the roller 12b and the input side disc 2 and cam plate 7. Specifically, the frictional forces (frictional forces generated on both sides of roller 12b) generated between roller 12b and outer surface 2b of input-side disc 2 and between roller 12b and cam plate 7 cooperate with the deformation restriction effect of restricting radial deformation of input shaft 1 via cam plate 7, so that radial displacement of input shaft 1, input-side disc 2, and cam plate 7 is restricted integrally by restriction member 70. Restriction member 70 is also formed of, for example, a cylindrical roller bearing, a ball bearing, or a sliding bearing. Therefore, the same effects as those of the first embodiment can be obtained.

[0040] FIG. 3 shows a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a third embodiment of the present invention. In this embodiment, a restricting member 70 is interposed between the outer peripheral surface 7a of the cam plate 7 constituting the pressing device 12 and the casing 50. The restricting member 70 restricts radial displacement of the right input disc 2 via the pressing device 12 while allowing axial movement of the input disc 2. In this case, the restricting member 70 also restricts radial displacement of the input disc 2 using the same principle of operation as in the second embodiment. Furthermore, the restricting member 70 is also formed of, for example, a cylindrical roller bearing, a ball bearing, or a sliding bearing. Therefore, the same effects as those of the first embodiment can be obtained.

[0041] 4 and 5 show cross-sectional views of essential parts of a toroidal-type continuously variable transmission according to a fourth embodiment of the present invention. In this embodiment, a restricting member 75 is interposed between the outer peripheral surface 2c of the input disc 2 and the casing 50. The restricting member 75 restricts radial displacement of the right input disc 2 associated with the outer surface 2b of the pressing device 12 while allowing axial movement of the input disc 2. Specifically, the restricting member 75 of this embodiment includes a plurality of rollers 73 that contact the outer peripheral surface 2c of the input disc 2 to support the input disc 2 in the radial direction, and springs 74 that are interposed between the casing 50 and each roller 73 and bias the roller 73 in a direction that brings it into contact with the outer peripheral surface 2c of the input disc 2. In this embodiment, three rollers 73 are provided, and as clearly shown in FIG. 5, these rollers 73 are arranged circumferentially around the input disc 2 at angular intervals of approximately 120 degrees.

[0042] In this embodiment, the regulating member 75 may be provided in a similar manner on the output side disc 3 or on the input side disc 2 on the left side in Fig. 1. In a similar manner, the regulating member 75 may be interposed between the casing 50 and the outer peripheral surface 7a of the cam plate 7 or the outer peripheral surface 12aa of the cage 12a that constitutes the pressing device 12.

[0043] According to the regulating member 75 of this embodiment, the input side disc 2 can be stably supported radially from multiple directions (three directions in this embodiment), and the input side disc 2 can move axially by resisting the biasing force of the spring 74.

[0044] FIG. 6 shows a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a fifth embodiment of the present invention. In this embodiment, a restricting member 80 is interposed between the outer peripheral surface 2c of the input disc 2 and the casing 50. The restricting member 80 restricts radial displacement of the right input disc 2 associated with the outer surface 2b of the pressing device 12 while allowing axial movement of the input disc 2. Specifically, the restricting member 80 in this embodiment is formed as a deep groove ball bearing and includes an outer ring member 84 and rolling elements 82 supported for free roll between an outer ring raceway surface 84a of the outer ring member 84 and an inner ring raceway surface 2ca formed on the outer peripheral surface 2c of the input disc 2. A radial gap s3 is provided between the outer ring member 84 and the casing 50 to allow axial movement of the input disc 2. The radial gap s3 is set larger than the amount of deformation of the input disc 2 that occurs during operation of the toroidal-type continuously variable transmission.

[0045] In this embodiment, the regulating member 80 may be provided in a similar manner on the output side disc 3 or on the input side disc 2 on the left side in Fig. 1. In a similar manner, the regulating member 80 may be interposed between the casing 50 and the outer peripheral surface 7a of the cam plate 7 or the outer peripheral surface 12aa of the cage 12a that constitutes the pressing device 12.

[0046] According to the regulating member 80 of this embodiment, the input side disc 2 can be stably supported radially over its entire circumference by the deep groove ball bearing, and the radial gap s3 provided between the casing 50 allows the input side disc 2 to move axially.

[0047] 7 shows a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a sixth embodiment of the present invention. In this embodiment, too, a restricting member 85 is interposed between the outer peripheral surface 2c of the input disc 2 and the casing 50. The restricting member 85 restricts radial displacement of the right input disc 2 associated with the outer surface 2b of the pressing device 12 while allowing axial movement of the input disc 2. Specifically, the restricting member 85 in this embodiment is formed as an angular ball bearing and includes an outer ring member 86 and rolling elements 88 that are rollably supported between an outer ring raceway surface 86a of the outer ring member 86 and an inner ring raceway surface 2d that is formed continuously across the outer peripheral surface 2c and the outer surface 2b of the input disc 2.

[0048] A radial gap s4 that allows axial movement of the input side disc 2 is provided between the outer ring member 86 and the casing 50. This radial gap s4 is set to be larger than the amount of deformation of the input side disc 2 that occurs with the operation of the toroidal-type continuously variable transmission. Furthermore, a spring 89 is interposed between the outer ring member 86 and the casing 50 as a biasing member that applies a preload in the axial direction from the outer surface 2b side of the input side disc 2 toward the inner surface 2a side. In this case, it is preferable that the preload applied by the spring 89 is a constant preload, and that the preload load is such that preload loss or excessive preload does not occur when the input side disc 2 moves axially.

[0049] In this embodiment, the regulating member 85 may be provided in a similar manner on the output side disc 3 or on the input side disc 2 on the left side in Fig. 1. In a similar manner, the regulating member 85 may be interposed between the casing 50 and the outer peripheral surface 7a and outer side surface 7b of the cam plate 7 or the outer peripheral surface 12aa and outer side surface 12ab of the cage 12a that constitutes the pressing device 12.

[0050] According to the restricting member 85 of this embodiment, the input side disc 2 can be stably supported in the radial direction over the entire circumference by the angular ball bearing, and the radial gap s4 provided between the casing 50 allows the input side disc 2 to move in the axial direction. Furthermore, since an axial preload directed from the outer surface 2b of the input side disc 2 to the inner surface 2a is applied by the spring 89, the preload can be applied to compensate for the axial movement of the input side disc 2, and axial deformation of the outer periphery of the input side disc 2 due to the normal force of the power rollers 11 can also be suppressed.

[0051] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiments, the pressing device is disposed on the outer surface of the input disc opposite the inner surface thereof and presses the input disc in the axial direction so as to bring the input disc and the output disc closer to each other. However, the pressing device may be disposed on the outer surface of the output disc opposite the inner surface thereof and presses the output disc in the axial direction so as to bring the input disc and the output disc closer to each other. Furthermore, all of the configurations applied to the input disc in the above-described embodiments can also be applied to the output disc. Furthermore, in the above-described embodiments, the present invention has been described using an example in which the present invention is applied to a double-cavity half-toroidal continuously variable transmission. However, the present invention is not limited thereto and can also be applied to single-cavity half-toroidal or full-toroidal toroidal continuously variable transmissions. Furthermore, the toroidal continuously variable transmission of the present invention is not limited in its applications and can be applied to various fields, such as automobiles and aircraft. Furthermore, within the scope of the present invention, some or all of the above-described embodiments may be combined, or part of the configuration may be omitted from one of the above-described embodiments. [Explanation of symbols]

[0052] 1 input shaft 2 Input disk 2a Inside surface 3 Output disk 3a Inside surface 7 Cam plate 11 Power Roller 12 Pressing device 12a retainer 50 casing 70, 75, 80, 85 Restriction member (restriction part) 73 Laura 74 Spring (biasing member) 84 Outer ring member 82 rolling elements 86 Outer ring member 88 Rolling elements 89 Spring (biasing member)

Claims

1. a power roller sandwiched between the input side disc and the output side disc; and a pressing device disposed on an outer surface of the input side disc or the output side disc opposite the inner surface of the input side disc or the output side disc, the pressing device pressing the input side disc or the output side disc in the axial direction so as to bring the input side disc and the output side disc closer to each other, the power roller sandwiched between the input side disc and the output side disc and a power roller sandwiched between the input side disc and the output side disc and a power roller disposed on an outer surface of the input side disc or the output side disc opposite the inner surface of the input side disc or the output side disc, the power roller sandwiched between the input side disc and the output side disc and a pressing device disposed on an outer surface of the input side disc or the output side disc opposite the inner surface of the input side disc or the output side disc, the power roller sandwiched between the input side disc and the output side disc and a restricting member that restricts radial displacement of at least one of the input side disc or the output side disc is supported on the casing side, The toroidal-type continuously variable transmission is characterized in that the regulating member is interposed between the outer peripheral surface of the input side disc or the output side disc, which includes the pressing device on the outer surface, and the casing.

2. 2. The toroidal-type continuously variable transmission according to claim 1, wherein the restricting member allows axial movement of at least one of the input side disc and the output side disc.

3. 3. The toroidal-type continuously variable transmission according to claim 1, wherein the regulating member regulates radial displacement of the input-side disc or the output-side disc associated with the outer surface of the pressing device.

4. 2. The toroidal-type continuously variable transmission according to claim 1, wherein the regulating member is a bearing including one of a cylindrical roller bearing, a ball bearing, and a sliding bearing.

5. 2. The toroidal-type continuously variable transmission according to claim 1, wherein the regulating member includes a plurality of rollers that contact the outer peripheral surface of the input side disc or the output side disc to support the input side disc or the output side disc in the radial direction, and a biasing member that is interposed between the casing and each of the rollers and biases the rollers in a direction that brings them into contact with the outer peripheral surface of the input side disc or the output side disc.

6. 2. The toroidal type continuously variable transmission according to claim 1, characterized in that the regulating member is formed as a deep groove ball bearing, the deep groove ball bearing has an outer ring member and rolling elements supported so as to be freely rollable between an outer ring raceway surface of the outer ring member and an inner ring raceway surface formed on the outer peripheral surface of the input side disc or the output side disc, and a radial gap allowing axial movement of the input side disc or the output side disc is provided between the outer ring member and the casing.

7. 2. The toroidal type continuously variable transmission according to claim 1, wherein the regulating member is formed as an angular contact ball bearing, the angular contact ball bearing having an outer ring member and rolling elements supported so as to be rollable between an outer ring raceway surface of the outer ring member and an inner ring raceway surface formed across the outer peripheral surface and the outer side surface of the input side disc or the output side disc, a radial gap that allows axial movement of the input side disc or the output side disc is provided between the outer ring member and the casing, and a biasing member that applies a preload in the axial direction from the outer surface side of the input side disc or the output side disc toward the inner surface side is interposed between the outer ring member and the casing.

8. 2. The toroidal type continuously variable transmission according to claim 1, wherein the pressing device is a loading cam type pressing device including a cam plate that rotates together with the input shaft, and a rolling element that is held by a cage so as to be able to roll between the cam plate and the outer surface of the input side disc or the output side disc, and the regulating member is interposed between the outer peripheral surface of the cage or the cam plate and the casing.

9. 9. The toroidal-type continuously variable transmission according to claim 8, wherein the regulating member includes a plurality of rollers that contact the outer peripheral surface of the cage or the cam plate to support the cage or the cam plate in the radial direction, and a biasing member that is interposed between the casing and each of the rollers and biases the rollers in a direction that brings them into contact with the outer peripheral surface of the cage or the cam plate.

10. 9. The toroidal type continuously variable transmission according to claim 8, characterized in that the regulating member is formed as a deep groove ball bearing, the deep groove ball bearing has an outer ring member and rolling elements supported so as to be freely rollable between an outer ring raceway surface of the outer ring member and an inner ring raceway surface formed on the outer peripheral surface of the cage or the cam plate, and a radial gap allowing axial movement of the input side disc or the output side disc is provided between the outer ring member and the casing.

11. 9. The toroidal type continuously variable transmission according to claim 8, wherein the regulating member is formed as an angular ball bearing, the angular ball bearing having an outer ring member and rolling elements supported so as to be rollable between an outer ring raceway surface of the outer ring member and an inner ring raceway surface formed across the outer peripheral surface and outer side surface of the cage or the cam plate, a radial gap that allows axial movement of the input side disc or the output side disc is provided between the outer ring member and the casing, and a biasing member that applies a preload in the axial direction from the outer surface side of the input side disc or the output side disc toward the inner surface side is interposed between the outer ring member and the casing.

12. 12. The toroidal-type continuously variable transmission according to claim 6, wherein the radial gap that allows axial movement of the input side disc or the output side disc is set to be larger than the amount of deformation of the disc that occurs with operation of the toroidal-type continuously variable transmission.

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