JP4623365B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to a toroidal continuously variable transmission that can be used for transmissions of automobiles and various industrial machines.

  For example, a double-cavity toroidal continuously variable transmission used as a transmission for an automobile is configured as shown in FIGS. As shown in FIG. 3, an input shaft (center shaft) 1 is rotatably supported inside the casing 50, and two input side disks 2, 2 and two outputs are provided on the outer periphery of the input shaft 1. Side disks 3 and 3 are attached. An output gear 4 is rotatably supported on the outer periphery of the intermediate portion of the input shaft 1. Output side disks 3 and 3 are connected to cylindrical flange portions 4a and 4a provided at the center of the output gear 4 by spline coupling.

  The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between an input side disk 2 and a cam plate 7 located on the left side in the drawing. . The output gear 4 is supported in the casing 50 via a partition wall 13 formed by coupling two members, so that the output gear 4 can rotate around the axis O of the input shaft 1 while the axis O. Directional displacement is prevented.

The output side disks 3, 3 are needle bearings 5, 5 interposed between the input shaft 1 and
The input shaft 1 is supported so as to be rotatable about the axis O of the input shaft 1. Further, the left input side disk 2 in the figure is supported on the input shaft 1 via a ball spline 6, and the right side input disk 2 in the figure is splined to the input shaft 1. Rotates with the input shaft 1. Also, the inner side surfaces (concave surfaces) 2a and 2a of the input side disks 2 and 2 and the output
A power roller 11 (see FIG. 4) is rotatably held between inner side surfaces (concave surfaces) 3a and 3a of the side disks 3 and 3.

  A step portion 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 3, and the step portion 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step portion 2b. At the same time, the back surface (right surface in FIG. 3) of the input side disk 2 is abutted against the loading nut 9. Thereby, the displacement of the input side disk 2 in the direction of the axis O with respect to the input shaft 1 is substantially prevented. Further, a disc spring 8 is provided between the cam plate 7 and the flange portion 1b of the input shaft 1, and this disc spring 8 is a concave surface 2a, 2a, 3a of each disk 2, 2, 3, 3. , 3a and the contact surface between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 are applied with a pressing force.

  4 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 4, a pair of trunnions 15, 15 that swing about a pair of pivots 14, 14 that are twisted with respect to the input shaft 1 are provided inside the casing 50. In FIG. 4, the input shaft 1 is not shown. Each trunnion 15, 15 has a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 4) of the support plate portion 16 so as to be bent toward the inner side surface of the support plate portion 16. have. The bent wall portions 20 and 20 form concave pocket portions P for accommodating the power rollers 11 in the trunnions 15 and 15. Further, the pivot shafts 14 and 14 are concentrically provided on the outer side surfaces of the bent wall portions 20 and 20, respectively.

  A circular hole 21 is formed in the center portion of the support plate portion 16, and a base end portion (first shaft portion) 23 a of the displacement shaft 23 is supported in the circular hole 21. Then, by swinging each trunnion 15, 15 about each pivot 14, 14, the inclination angle of the displacement shaft 23 supported at the center of each trunnion 15, 15 can be adjusted. The power rollers 11 and 11 are rotatably supported around the distal end portion (second shaft portion) 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15 and 15. 11 and 11 are sandwiched between the input side disks 2 and 2 and the output side disks 3 and 3. In addition, the base end part 23a and the front-end | tip part 23b of each displacement shaft 23 and 23 are mutually eccentric.

  Further, the pivot shafts 14 and 14 of the trunnions 15 and 15 are supported so as to be swingable and axially displaceable with respect to the pair of yokes 23A and 23B (back and front directions in FIG. 3, up and down direction in FIG. 4). The trunnions 15 and 15 are restricted from moving in the horizontal direction by the yokes 23A and 23B. Each yoke 23A, 23B is formed in a rectangular shape by pressing or forging a metal such as steel. Four circular support holes 18 are provided at the four corners of each of the yokes 23 </ b> A and 23 </ b> B, and the pivot shafts 14 provided at both ends of the trunnion 15 swing through the radial needle bearings 30. It is supported freely. Further, a circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (left and right direction in FIG. 3). 64 and 68 are fitted inside. That is, the upper yoke 23A is swingably supported by the spherical post 64 supported by the casing 50 via the fixing member 52, and the lower yoke 23A is composed of the spherical post 68 and the cylinder supporting the same. 31 is supported by the upper cylinder body 61 so as to be swingable.

  The displacement shafts 23 and 23 provided in the trunnions 15 and 15 are provided at positions 180 degrees opposite to the input shaft 1. Further, the direction in which the distal end portion 23b of each of the displacement shafts 23, 23 is eccentric with respect to the base end portion 23a is the same direction as the rotational direction of both the disks 2, 2, 3, 3 (in FIG. (Reverse direction). Further, the eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 1 is disposed. Accordingly, the power rollers 11 and 11 are supported so that they can be slightly displaced in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component member based on the thrust load generated by the pressing device 12, each component This displacement is absorbed without applying an excessive force to the member.

  Further, between the outer surface of the power roller 11 and the inner surface of the support plate portion 16 of the trunnion 15, a thrust ball bearing 24 that is a thrust rolling bearing, and a thrust needle bearing, in order from the outer surface side of the power roller 11. 25. Among these, the thrust ball bearing 24 supports the rotation of each power roller 11 while supporting the load in the thrust direction applied to each power roller 11. Each of the thrust ball bearings 24 is composed of a plurality of balls 26, 26, an annular retainer 27 for holding the balls 26, 26 in a freely rolling manner, and an annular outer ring 28. ing. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface (large end surface) of each power roller 11, and the outer ring raceway is formed on the inner side surface of each outer ring 28.

  The thrust needle bearing 25 is sandwiched between the inner surface of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. Such a thrust needle bearing 25 supports the thrust load applied to each outer ring 28 from the power roller 11, while the power roller 11 and the outer ring 28 swing around the base end portion 23 a of each displacement shaft 23. Allow.

  Further, driving rods (trunnion shafts) 29 and 29 are provided at one end portions (lower end portions in FIG. 4) of the trunnions 15 and 15, respectively, and a driving piston ( Hydraulic pistons) 33, 33 are fixed. Each of these drive pistons 33 and 33 is oil-tightly fitted in a drive cylinder 31 constituted by an upper cylinder body 61 and a lower cylinder body 62. The drive pistons 33 and 33 and the drive cylinder 31 constitute a drive device 32 that displaces the trunnions 15 and 15 in the axial direction of the pivots 14 and 14 of the trunnions 15 and 15.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input side disks 2 and 2 via the pressing device 12. Then, the rotation of the input side disks 2 and 2 is transmitted to the output side disks 3 and 3 via the pair of power rollers 11 and 11, and the rotation of the output side disks 3 and 3 is further transmitted to the output gear 4. It is taken out more.

  When changing 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 and 33 are displaced, the pair of trunnions 15 and 15 are displaced in directions opposite to each other. For example, the power roller 11 on the left side in FIG. 4 is displaced to the lower side in the figure, and the power roller 11 on the right side in the figure is displaced to the upper side in the figure. As a result, the peripheral surfaces 11a and 11a of the power rollers 11 and 11 act on contact portions of the input side disks 2 and 2 and the inner side surfaces 2a, 2a, 3a and 3a of the output side disks 3 and 3, respectively. The direction of the tangential force changes. As the force changes, the trunnions 15 and 15 swing in opposite directions around the pivots 14 and 14 pivotally supported by the yokes 23A and 23B.

  As a result, the contact position between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 3a changes, and the rotational speed ratio between the input shaft 1 and the output gear 4 changes. Further, 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 and 11 and the outer rings attached to the power rollers 11 and 11 will be described. 28 and 28 slightly rotate around the base end portions 23a and 23a of the displacement shafts 23 and 23, respectively. Since the thrust needle bearings 25 and 25 exist between the outer side surfaces of the outer rings 28 and 28 and the inner side surfaces of the support plate portions 16 constituting the trunnions 15 and 15, respectively, the rotation is performed smoothly. Is called. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 23, 23 can be small.

  By the way, in such a toroidal type continuously variable transmission, the power is shearing force of oil (traction oil) between the input / output side disks 2 and 3 and the power roller 11 (between the traction surface (rolling surface)). (See, for example, Patent Document 1 and Patent Document 2). Since the friction coefficient of the traction oil is determined, it is necessary to apply a large load (pressing force) to the contact point between the input / output side disks 2 and 3 and the power roller 11 in order to transmit high torque.

  As a method of applying the load, there are a case where the above-described loading cam type pressing device 12 which mechanically generates a load proportional to an input torque and a case where a hydraulic pressing device is used. When only the loading cam type pressing device 12 is used, a thrust (pushing force of the input side disk) proportional to only the input torque is generated. Therefore, depending on the gear ratio, the contact portion between the disk and the roller may be excessive. May cause a reduction in transmission efficiency and durability. On the other hand, when a hydraulic pressing device is used, an optimum pressing force can be applied according to the shift, oil temperature, rotation speed, and the like. Therefore, the transmission is more efficient than the loading cam type pressing device. Durability can be improved.

On the other hand, the purpose of abolition of such a wide-range of and starting device (having a plurality of speed modes) toroidal type continuously variable transmission and a planetary gear mechanism and capable of speeds mode switching in combination with a transmission is known Yes.

JP 2003-343675 A JP 2003-278869 A

  In the transmission having the planetary gear mechanism, torque reversal occurs at the mode switching point, so that torque shift (a phenomenon in which the power roller 11 is deviated from the central axis, side slip occurs, and the set gear ratio deviates). ) Is likely to occur. This torque shift occurs due to a difference in deformation due to fluctuations in the pressing force and a backlash / stiffness between the trunnion and the power roller due to fluctuations in the traction force. When this torque shift occurs, an impact is applied at the time of mode switching, and riding comfort is reduced. In addition, when a sudden torque shift occurs, there is a possibility that problems such as gross slip may occur.

  The present invention has been made in view of the above circumstances, and can provide an optimum pressing force depending on the gear ratio, and a desired gear ratio can be obtained with a lower pressing force than the conventional one, resulting in a torque shift. An object of the present invention is to provide a toroidal continuously variable transmission that can be mitigated.

To achieve the above object, the toroidal continuously variable transmission according to claim 1 rotates concentrically and with an input shaft to which rotational torque is input and respective inner surfaces facing each other. An input disk and an output disk that are freely supported by the input shaft, a power roller sandwiched between the input disk and the output disk, and between the input / output disk and the power roller A toroidal continuously variable transmission having a plurality of speed modes for extracting power from each planetary gear by being combined with a plurality of planetary gear mechanisms. , at least the speed mode the input side inner surface area or the fine groove is provided et the vicinity of the disk in contact with the power roller switching point Based on the design traction coefficient is increased by Rukoto, the pressing force applied between the pressing device and the output side disc and the power roller, has the fine groove is provided at the time of switching the speed mode It is characterized by being lower than the pressing force suitable for the case where there is not .

Further, the toroidal type continuously variable transmission according to claim 2 is the invention according to claim 1, wherein the fine groove, the inner surface of the radially outer portion and the output side disks of the inner side surface of the input side disk It is characterized by each being provided in the radial direction inner side part.

In the toroidal-type continuously variable transmission of the present invention, since a hydraulic pressing device is used, an optimal pressing force can be applied depending on the gear ratio, and at least at the speed mode switching point, Since the fine grooves are provided in or near the inner side surface area of the input / output side disk in contact with each other, the design traction coefficient can be increased, and the pressing force can be decreased. Therefore, the torque shift can be reduced by reducing the pressing force around the speed mode switching point, or a margin for the gross slip can be secured at the speed mode switching point.

  The fine grooves preferably have a depth of about 1 to 10 μm and a pitch of about 100 to 300 μm. In addition, when the roughness of the fine groove is large, the rolling life may be shortened. Therefore, it is preferable not to provide the fine groove on the entire surface of the traction surface, and to provide the fine groove only at the speed mode switching point. . This is also advantageous in processing. In other words, it is necessary to round the head or corner in the fine groove, and the finishing process for that is done separately, but if the fine groove is provided only at the speed mode switching point and the finishing range is narrowed, Processing costs can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the present invention lies in the disk surface structure for reducing the pressing force by the pressing device, and the other configurations and operations are the same as the conventional configurations and operations described above. only refer to characteristic parts, for other portions, bear in briefly described with the same reference numerals as FIGS.

  FIG. 1 shows a structure in which a toroidal type continuously variable transmission is incorporated in a geared neutral type continuously variable transmission. This continuously variable transmission is a combination of a toroidal type continuously variable transmission unit 147 having substantially the same structure as that shown in FIG. 3 and first to third planetary gear type transmission units 148, 149, 150. And has an input shaft 1 and an output shaft 151. Further, a transmission shaft 152 is provided between the input shaft 1 and the output shaft 151 and is concentric with the shafts 1 and 151 and rotatable with respect to the shafts 1 and 151. The pressing device 12A is hydraulic, and the input / output side disks 2 and 3 are supported by a hollow shaft 153 through which the input shaft 1 passes. Further, the input shaft 1 receives a rotational force from the drive shaft 22 via the pressing device 12A. As is well known, according to this structure, it is possible to shift between a plurality of speed modes (for example, the low speed mode and the high speed mode) by extracting power from each planetary gear type transmission unit.

  As shown in FIG. 2, the pressing device 12 </ b> A includes a first cylinder portion 141 coupled to the input end portion 1 a of the input shaft 1, a second cylinder portion 159 integrated with the input side disk 2, and a first cylinder portion 159. The annular body 161 and the second annular body 160 are provided.

  The first cylinder part 141 is located outside the outer periphery of the second cylinder part 159, and is arranged in a state of facing the back surface 2 d of the input side disk 2. The second cylinder part 159 is formed in a cylindrical shape and extends from the outer peripheral edge of the input side disk 2 toward the first cylinder part 141.

  The second annular body 160 has an inner peripheral surface thereof fitted to the outer peripheral surface of the input shaft 1 and an outer peripheral surface thereof fitted to the inner peripheral surface of the second cylinder part 159, so that the input side disk 2 It is arranged in a state facing the rear surface 2d of the. The first annular body 161 has an inner peripheral surface fitted to the outer peripheral surface of the input shaft 1 and an outer peripheral surface fitted to the inner peripheral surface of the first cylinder portion 141. The second annular body 160 and the first cylinder portion 141 are disposed.

  A space between the first cylinder part 141 and the annular body 161 constitutes a first hydraulic chamber (oil chamber) 170. The first hydraulic chamber 170 is kept fluid tight by a plurality of seal members 171. Further, the space between the second cylinder portion 159 and the second annular body 160 constitutes a second hydraulic chamber (oil chamber) 167. The second hydraulic chamber 167 is kept fluid tight by a plurality of seal members 168. A space 175 located between the second annular body 160 and the first annular body 161 is an air chamber. The air chamber 175 is kept fluid tight by a plurality of seal members 168 and 171. The second cylinder 159 has a gap s that also functions as a communication groove that allows the air chamber 175 to communicate with the outside. The second cylinder 159 has a gap between the first annular body 161 and the first cylinder via the gap s. It can come into contact with the annular body 161. Note that an oil passage is formed in the drive shaft 22 and the input shaft 1 in order to supply oil to the hydraulic chambers 167 and 170.

Further, the power at the switching point of the speed mode, that is, the radially outer portion (outer peripheral portion) of the inner side surface 2a of the input side disc 2 and the radially inner portion (center portion) of the inner side surface 3a of the output side disc 3 A fine groove 200 is provided in or near the inner surface area of the input / output side disks 2 and 3 in contact with the roller 11. The fine groove 200 has a depth D set to about 1 to 10 μm and a pitch P1 set to about 100 to 300 μm (see FIG. 2B). The fine groove 200 is rounded at the head 202 or the corner 204 in another finishing process. Further, the fine grooves 200, the disk inner surface area other than that shown in FIG. 2 (e.g., the entire area of the disk inner surface) may be provided on.

As described above, in the toroidal-type continuously variable transmission according to the present embodiment, the hydraulic pressing device 12A is used, so that an optimum pressing force can be applied depending on the gear ratio. Further, in the present embodiment, since the fine groove 200 is provided at or near the inner surface area of the input / output side disks 2 and 3 that are in contact with the power roller 11 at least at the speed mode switching point, the design traction coefficient Therefore, the pressing force can be reduced. Therefore, the torque shift can be reduced by reducing the pressing force around the speed mode switching point, or a margin for the gross slip can be secured at the speed mode switching point.

  If the roughness of the fine groove 200 is large, the rolling life may be shortened. Therefore, the fine groove 200 is not provided on the entire surface of the traction surface, and the speed mode switching point as in this embodiment is not provided. It is preferable to provide the fine groove 200 only on the surface. This is also advantageous in processing. That is, in the fine groove 200, as described above, it is necessary to round the head portion 202 or the corner portion 204, and a finishing process is separately performed. However, the fine groove 200 is provided only at the speed mode switching point. If the finishing range is narrowed, the processing cost can be reduced.

  The present invention can be applied to a full toroidal continuously variable transmission having no trunnion, in addition to various half toroidal continuously variable transmissions such as a single cavity type and a double cavity type.

It is principal part sectional drawing of the toroidal type continuously variable transmission which concerns on embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of a main part of the toroidal type continuously variable transmission of FIG. 2. It is sectional drawing which shows an example of the specific structure of the half toroidal type continuously variable transmission conventionally known. It is sectional drawing which follows the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Input side disk 2a inner surface 3 Output side disk 3a inner surface 11 Power roller 12A Press apparatus 148, 149, 150 Planetary gear type speed change unit 200 Fine groove

Claims (2)

An input shaft to which rotational torque is input, an input-side disk and an output-side disk supported on the input shaft so as to be concentrically and freely rotatable with their inner surfaces facing each other, and the input-side disk And a plurality of planetary gears including a power roller sandwiched between the output side disk and a hydraulic pressing device that applies a predetermined pressing force between the input / output side disk and the power roller. In a toroidal continuously variable transmission having a plurality of speed modes for extracting power from each planetary gear by being combined with a mechanism,
At the time of switching the speed mode, the design traction coefficient is increased by providing a fine groove in or near the inner surface area of the input / output side disk that contacts the power roller at least at the speed mode switching point. A toroidal type characterized in that the pressing force applied between the input / output side disk and the power roller by the pressing device is lower than the pressing force suitable when the fine groove is not provided. Continuously variable transmission. 2. The toroidal type non-circularity according to claim 1, wherein the fine grooves are provided in a radially outer portion of an inner surface of the input side disc and a radially inner portion of an inner surface of the output side disc. Step transmission.

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