JP2006125444A - Toroidal continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable and small toroidal continuously variable transmission whose speed ratio is used for imparting optimum pushing force and whose desired speed ratio is given by pushing force lower than conventional one. <P>SOLUTION: The toroidal continuously variable transmission comprises fine grooves 200 provided on at least a radial inside portion on an inner peripheral face 2a of an input side disc 2 and a radial outside portion on an inner peripheral face 3a of an output side disc 3, namely in contact regions between each of the input and output side discs 2, 3 and a power roller 11 almost corresponding to each other during low speed operation (deceleration). Thus, a design traction coefficient is increased to reduce pushing force and improve the resistance of components, consequently reducing the size of the transmission. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 an automobile transmission is configured as shown in FIGS. As shown in FIG. 4, 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 and 3 are supported by needle bearings 5 and 5 interposed between the input shaft 1 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. A power roller 11 (see FIG. 5) is rotatable between the inner side surfaces (concave surfaces) 2a and 2a of the input side disks 2 and 2 and the inner side surfaces (concave surfaces) 3a and 3a of the output disks 3 and 3. It is pinched.

  A step 2b is provided on the inner peripheral surface 2c of the input disk 2 located on the right side in FIG. 4, and the step 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step 2b. At the same time, the back surface (the right surface in FIG. 4) 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.

  FIG. 5 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 5, a pair of trunnions 15, 15 that swing around a pair of pivots 14, 14 that are twisted with respect to the input shaft 1 are provided inside the casing 50. In addition, illustration of the input shaft 1 is abbreviate | omitted in FIG. Each trunnion 15, 15 is a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 5) of the support plate portion 16 so as to be bent toward the inner surface side of the support plate portion 16. have. The bent wall portions 20, 20 form concave pocket portions P for accommodating the power rollers 11 in the trunnions 15, 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. 4 and up and down directions in FIG. 5). 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. In addition, a circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (left-right direction in FIG. 4). 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, drive rods (trunnion shafts) 29 and 29 are provided at one end portions (lower end portions in FIG. 5) of the trunnions 15 and 15, respectively, and a drive 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. 5 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.

JP 2003-343675 A JP 2003-278869 A

  However, at low speed, a high pressing force is required due to the contact radius and the transmission torque between the input / output disk and the power roller (in a toroidal continuously variable transmission, the disk and The contact radius between the power roller and the required pressing force is different. Therefore, the contact portion between the disk and the power roller (in the case of a half-toroidal continuously variable transmission, the power roller 11 The bearing pressure is also high, which is problematic in terms of durability. Further, increasing the durability results in an increase in the size of each component.

  The present invention has been made in view of the above circumstances, and can provide an optimum pressing force by a gear ratio, and a desired gear ratio can be obtained with a pressing force lower than that of the prior art. An object of the present invention is to provide a toroidal continuously variable transmission.

  In order to achieve the object, the toroidal continuously variable transmission according to claim 1 is configured to be concentric with an input shaft to which rotational torque is input and respective inner peripheral surfaces thereof facing each other. An input-side disk and an output-side disk rotatably supported by the input shaft, a power roller sandwiched between the input disk and the output-side disk, and between the input / output-side disk and the power roller A toroidal-type continuously variable transmission provided with a hydraulic pressing device for applying a predetermined pressing force to at least a radially inner portion of an inner peripheral surface of the input side disk and an inner peripheral surface of the output side disk Each of these is characterized in that a fine groove is provided in each radially outer portion.

  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 transmission gear ratio, and at least the radial direction of the inner peripheral surface of the input side disk Since the inner portion and the radially outer portion of the inner peripheral surface of the output side disk, i.e., the contact region between the input / output side disk and the power roller that substantially corresponds at the time of low speed (deceleration), a fine groove is provided, Design traction coefficient can be increased. Therefore, the pressing force can be reduced, and the resistance of each component (for example, a disk, a power roller, a trunnion, a shaft, etc.) can be improved, and as a result, a reduction in the size of the transmission can be achieved.

  The fine grooves preferably have a depth of about 1 to 10 μm and a pitch of about 100 to 300 μm. Also, when the roughness of the fine groove is large, the rolling life may be shortened. Therefore, the fine groove is not provided on the entire surface of the traction surface, and the fine groove is fine only on the low speed side where the usage frequency is low and the load is high. It is preferable to provide a groove. This is also advantageous in processing. In other words, it is necessary to round off the head or corner of the fine groove, and a separate finishing process will be performed. However, if the fine groove is provided only on the low speed side and the finishing range is narrowed, the processing cost is reduced. Can be lowered.

  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 the characteristic part of FIG. 5 will be referred to, and other parts will be simply described with the same reference numerals as those in FIGS.

  1 and 2 show a half-toroidal continuously variable transmission according to an embodiment of the present invention. As shown in FIG. 1, a hydraulic pressing device 12 </ b> A that presses the input side disk 2 in the axial direction is provided on the back surface 2 d of the input side disk 2 positioned on the input side of the input shaft 1. The pressing device 12A includes a first cylinder portion 141 coupled to the input end portion 1a of the input shaft 1, a second cylinder portion 159 integrated with the input side disk 2, a first annular body 161, 2 annular bodies 160.

  The first cylinder part 141 is engaged with 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 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 first cylinder portion 141. The 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. In order to supply oil to the hydraulic chambers 167 and 170, an oil passage is formed in the input shaft 22 on the engine side.

  Further, as clearly shown in FIG. 2, fine grooves 200 are formed in the radially inner portion of the inner peripheral surface 2a of the input side disk 2 and the radially outer portion of the inner peripheral surface 3a of the output side disc 3, respectively. Is provided. 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 groove 200 may be provided in a disc inner peripheral surface region (for example, the entire region of the disc inner peripheral surface) other than that shown in FIG.

  In the above configuration, when the rotational speeds of the input shaft 1 and the output shaft (not shown) are changed, and when deceleration is performed between the input shaft 1 and the output shaft, each trunnion is centered on the pivot 14. 15, the peripheral surface 11 a of each power roller 11 has a radially inner portion (center portion) of the inner peripheral surface 2 a of the input side disk 2 and a radially outer portion of the inner peripheral surface 3 a of the output side disc 3. Each displacement shaft 23 is inclined so as to come into contact with the (outer peripheral portion). On the other hand, when increasing the speed, each trunnion 15 is swung, and the peripheral surface 11a of each power roller 11 is output with the radially outer portion (outer peripheral portion) of the inner peripheral surface 2a of the input side disk 2. Each displacement shaft 23 is inclined so as to abut against the radially inner portion (center portion) of the inner peripheral surface 3a of the side disk 3 respectively. In other words, in the present embodiment, the fine groove 200 is provided in the contact area between the input / output side disks 2 and 3 and the power roller 11 that substantially corresponds to low speed (deceleration).

  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 optimal pressing force can be applied depending on the gear ratio. Further, in the present embodiment, at least the radially inner portion of the inner peripheral surface 2a of the input side disk 2 and the radially outer portion of the inner peripheral surface 3a of the output side disc 3, that is, an input substantially corresponding to low speed (deceleration). Since the fine groove 200 is provided in the contact area between the output side disks 2 and 3 and the power roller 11, the design traction coefficient can be increased. Therefore, the pressing force can be reduced and the resistance of each component (for example, the disks 2 and 3, the power roller 11, the trunnion 15, the shaft 1, etc.) can be improved, and consequently the transmission can be reduced in size. can do.

  In addition, since the rolling life may be shortened when the roughness of the fine groove 200 is large, the fine groove 200 is not provided on the entire surface of the traction surface, and the frequency of use is low as in this embodiment. It is preferable to provide the fine groove 200 only on the low speed side where the load is high. 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 for that purpose is performed separately. However, the fine groove 200 is provided only on the low speed side to complete the finishing range. If the width is narrowed, the processing cost can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the gist thereof. For example, in the embodiment described above, the present invention is applied to a half-toroidal continuously variable transmission, but the present invention is applied to a full toroidal continuously variable transmission having no trunnion as shown in FIG. Can also be applied. That is, in the full toroidal continuously variable transmission shown in FIG. 3, fine grooves are respectively formed in the radially inner portion of the inner peripheral surface 2a of the input side disk 2 and the radially outer portion of the inner peripheral surface 3a of the output side disc 3. 200 may be provided.

It is principal part sectional drawing of the half 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 half-toroidal continuously variable transmission of FIG. 2. It is principal part sectional drawing of the full toroidal type continuously variable transmission which concerns on a modification. 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 peripheral surface 3 Output side disk 3a Inner peripheral surface 11 Power roller 200 Fine groove

Claims (1)

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 peripheral surfaces facing each other, and the input disk A toroidal-type continuously variable transmission comprising 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 the machine
A toroidal continuously variable transmission, characterized in that fine grooves are provided at least in the radially inner portion of the inner peripheral surface of the input side disk and in the radially outer portion of the inner peripheral surface of the output side disc.

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