JP2015132298A - Toroidal type stepless transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure capable of sufficiently positioning the radial direction of a retainer 24b constituting a radial needle bearing 20b for supporting each power roller 6, and suppressing the increase in a rotational resistance of each retainer 24b or the temperature rise of each radial needle bearing 20b at the time of transmitting a high torque.SOLUTION: The positional regulations on the radial directions of these individual retainers 24b are made by the inner ring guide to make the individual inner circumferences and the outer circumferences of the individual roller support shafts 12 proximately opposed. On the other hand, the differences in the non-transmission state between the internal diameter r of the center holes 19 of the individual power rollers 6 and the external diameter d of the individual retainers 24 are made larger than the maximum of the deformation quantity of the center hole 19 of those individual power rollers 6 on the basis of the power transmission.

Description

  The present invention relates to a generator (generator) used in, for example, an automatic transmission for a vehicle (automobile), an automatic transmission for a construction machine (construction machine), an aircraft (a fixed wing aircraft, a rotary wing aircraft, an airship, etc.), etc. The present invention relates to an improvement of a toroidal continuously variable transmission that is used as an automatic transmission for adjusting the operating speed of various industrial machines such as automatic transmissions and pumps.

  The use of a half-toroidal toroidal continuously variable transmission as a transmission for an automobile is described in many publications such as Patent Documents 1 to 4 and partially implemented, and is well known. Further, a structure in which a toroidal type continuously variable transmission and a planetary gear mechanism are combined to widen the adjustment range of the gear ratio is also described in many publications such as Patent Document 5 and has been widely known. 3 to 4 show a first example of a toroidal type continuously variable transmission described in each of these patent documents and widely known in the past. In the case of the first example of this conventional structure, a pair of input disks 2 and 2 are disposed around the portions near both ends of the input rotation shaft 1 in a state where the inner surfaces, each of which is a toroidal curved surface, face each other. The rotation synchronized with the rotating shaft 1 is supported. An output tube 3 is supported around the intermediate portion of the input rotary shaft 1 so as to be rotatable with respect to the input rotary shaft 1. Further, on the outer peripheral surface of the output cylinder 3, an output gear 4 is fixed at the center in the axial direction, and a pair of output disks 5 and 5 are connected to both ends in the axial direction by spline engagement. Supports the rotation synchronized with. In this state, the inner surfaces of the output disks 5 and 5, each of which is a toroidal curved surface, are opposed to the inner surfaces of the input disks 2 and 2.

  Further, a plurality of power rollers 6 and 6 each having a partially spherical convex surface are sandwiched between the input disks 2 and 2 and the output disks 5 and 5. Each of these power rollers 6 and 6 is rotatably supported by trunnions 7 and 7 which are support members described in the claims. These trunnions 7 and 7 are respectively connected to the respective disks 2 and 5. Is supported so as to be swingable and displaceable about the tilting shafts 8 and 8 that are in a twisted position with respect to the central axis. That is, each of the trunnions 7 and 7 includes a pair of tilting shafts 8 and 8 provided concentrically with each other at both axial ends, and a supporting beam existing between the tilting shafts 8 and 8. These tilting shafts 8 and 8 are pivotally supported with respect to the support plates 10 and 10 via radial bearings 11 and 11, respectively.

  Each of the power rollers 6 and 6 has roller support shafts 12 and 12 whose base half and tip half are eccentric from each other on the inner side surfaces of the support beam portions 9 and 9 constituting the trunnions 7 and 7, respectively. The roller support shafts 12 and 12 can be rotated about the front half of the roller support shafts 12 through a plurality of rolling bearings, and can be slightly swung about the base half of the roller support shafts 12 and 12. It is supported by.

  First, thrust ball bearings 13 and 13 and thrust needle bearings 14 are provided between the outer surfaces of the power rollers 6 and 6 and the inner surfaces of the support beam portions 9 and 9 constituting the trunnions 7 and 7. , 14 are provided in order from the power rollers 6 and 6 side. Of these, the thrust ball bearings 13 and 13 support the rotation of the power rollers 6 and 6 while supporting the load in the thrust direction applied to the power rollers 6 and 6. Each thrust ball bearing 13, 13 has a plurality of balls 18 between an inner ring raceway 15 formed on the outer side surface of each of the power rollers 6, 6 and an outer ring raceway 17 formed on the inner side surface of the outer ring 16. , 18 are provided to be able to roll. The thrust needle roller bearings 14, 14 support thrust loads applied to the outer rings 16, 16 constituting the thrust ball bearings 13, 13 from the power rollers 6, 6. In addition, the front half portions of the roller support shafts 12 and 12 are allowed to swing around the base half portions of the roller support shafts 12 and 12.

  Further, radial needle bearings 20 and 20 are provided between the outer peripheral surfaces of the tip portions of the roller support shafts 12 and 12 and the inner peripheral surfaces of the center holes 19 and 19 of the power rollers 6 and 6, respectively. In order to configure each of these radial needle bearings 20, 20, the outer peripheral surface of the tip of each of the roller support shafts 12, 12 is an inner ring raceway 21, and the inner peripheral surface of each of the center holes 19, 19 is an outer ring raceway 22. . A plurality of needles 23, 23 are respectively provided between the inner ring raceway 21 and the outer ring raceway 22 so as to be freely rollable while being held by the cage 24.

During operation of the toroidal type continuously variable transmission as described above, one input disk 2 (left side in FIG. 3) is rotationally driven by the drive shaft 25 via the pressing device 26. As a result, the pair of input disks 2 and 2 supported at both ends of the input rotating shaft 1 rotate synchronously while being pressed in a direction approaching each other. The rotation is transmitted to the output disks 5 and 5 through the power rollers 6 and 6 and is taken out from the output gear 4. When changing the gear ratio between the input rotary shaft 1 and the output gear 4, the trunnions 7, 7 are displaced in the axial direction of the tilt shafts 8, 8 by hydraulic actuators 27, 27. . As a result, the direction of the tangential force acting on the rolling contact portion (traction portion) between the peripheral surface of each of the power rollers 6 and 6 and the inner surface of each of the disks 2 and 5 changes (in the rolling contact portion). Side slip occurs). As the direction of the force changes, the trunnions 7 and 7 swing around their tilting shafts 8 and 8, and the peripheral surfaces of the power rollers 6 and 6 and the disks 2 and 8. The contact position with the inner surface of 5 changes. The circumferential surfaces of the power rollers 6 and 6 are in rolling contact with the radially outer portions of the inner surfaces of the input disks 2 and 2 and the radially inner portions of the inner surfaces of the output disks 5 and 5. By doing so, the gear ratio between the input rotary shaft 1 and the output gear 4 is increased. On the other hand, the peripheral surfaces of the power rollers 6 and 6 are arranged radially inwardly on the inner side surfaces of the input disks 2 and 2 and radially outwardly on the inner side surfaces of the output disks 5 and 5. If it is brought into rolling contact with the portion, the gear ratio between the input rotary shaft 1 and the output gear 4 becomes the deceleration side.

  When the toroidal type continuously variable transmission as described above is operated, the members used for power transmission, that is, the input and output disks 2 and 5 and the power rollers 6 and 6 are connected to the pressing device 26. It is elastically deformed based on the pressing force generated. In accordance with this elastic deformation, the input and output disks 2 and 5 are displaced in the axial direction. Further, the pressing force generated by the pressing device 26 increases as the torque transmitted by the toroidal-type continuously variable transmission increases, and the amount of elastic deformation of the members 2, 5, 6 increases accordingly. Accordingly, in order to properly maintain the contact state between the inner surface of each of the input and output disks 2 and 5 and the peripheral surface of each of the power rollers 6 and 6 regardless of the fluctuation of the torque, the trunnions 7 and 7 7, a mechanism for displacing the power rollers 6 and 6 in the axial direction of the disks 2 and 5 is required. In the case of the first example of the conventional structure described above, the first half of each of the roller support shafts 12 and 12 that support each of the power rollers 6 and 6 is similarly oscillated and displaced about the base half. The power rollers 6, 6 are displaced in the axial direction.

  Further, as a technique for facilitating parts production, parts management, and assembling work, Patent Document 3 describes a structure as shown in FIGS. The trunnion 7a constituting the second example of this conventional structure exists between a pair of tilting shafts 8a, 8b concentrically provided at both ends, and between these tilting shafts 8a, 8b, and at least Support is provided with a cylindrical convex surface 28 on the inner side (upper side in FIGS. 6, 9, 10) of the input and output disks 2, 5 (see FIG. 3) in the radial direction (the vertical direction in FIGS. And a beam portion 29. The two tilting shafts 8a and 8b are supported on the support plates 10 and 10 (see FIG. 4) via radial bearings 11a and 11a, respectively, so as to be swingable and axially displaceable.

  Further, as shown in FIGS. 6 and 9, the center axis A of the cylindrical convex surface 28 is parallel to the center axis B of the both tilt axes 8a and 8b, and the center axis B of these tilt axes 8a and 8b. Rather than the outer side (the lower side of FIGS. 6, 9, 10) in the radial direction of the disks 2, 5. Further, a concave portion 30 having a partially cylindrical surface is radially crossed on the outer surface of the outer ring 16a constituting the thrust ball bearing 13a provided between the support beam portion 29 and the outer surface of the power roller 6a. It is provided in the state. And this recessed part 30 and the cylindrical convex surface 28 of the said support beam part 29 are engaged, The rocking | fluctuation displacement regarding the axial direction of each said disk 2 and 5 is enabled for the said outer ring 16a with respect to the said trunnion 7a. I support it.

  Further, a roller support shaft 12a is fixed integrally with the outer ring 16a at the center of the inner surface of the outer ring 16a constituting the thrust ball bearing 13a, and the power roller 6a is disposed around the roller support shaft 12a with a radial needle. The bearing 20a is rotatably supported. Furthermore, a pair of stepped surfaces 31 and 31 facing each other are provided on the inner surface of the trunnion 7a at a continuous portion between both ends of the support beam portion 29 and the pair of tilting shafts 8a and 8b. . Then, these stepped surfaces 31, 31 and the outer peripheral surface of the outer ring 16a constituting the thrust ball bearing 13a are brought into contact with or in close proximity to each other, and the traction force applied from the power roller 6a to the outer ring 16a is It can be supported by the stepped surfaces 31, 31.

According to the toroidal type continuously variable transmission of the second example of the conventional structure configured as described above, the power roller 6a is displaced in the axial direction of each of the disks 2 and 5, and the amount of elastic deformation of each constituent member is increased. Regardless of the change, a structure capable of appropriately maintaining the contact state between the peripheral surface of the power roller 6a and the inner surfaces of the disks 2 and 5 can be configured simply and at low cost.
That is, during operation of the toroidal continuously variable transmission, the power rollers 6a are displaced in the axial direction of the disks 2 and 5 based on elastic deformation of the input and output disks 2 and 5 and the power rollers 6a. When necessary, the outer ring 16a of the thrust ball bearing 13a that rotatably supports each of the power rollers 6a is provided with a concave portion 30 having a partial cylindrical surface provided on the outer surface and a cylindrical convex surface 28 of the support beam portion 29. The cylindrical convex surface 28 is oscillated and displaced about the central axis A while sliding the contact surface. Based on this oscillating displacement, a portion of the peripheral surface of each power roller 6a that is in rolling contact with one axial side surface of each disk 2, 5 is displaced in the axial direction of each disk 2, 5; The contact state is properly maintained.

  As described above, the central axis A of the cylindrical convex surface 28 is larger in diameter than the central axes B of the tilting shafts 8a and 8b, which are the oscillation centers of the trunnions 7a during the shifting operation. Exists with respect to the direction. Therefore, the radius of the rocking displacement about the central axis A of the cylindrical convex surface 28 is larger than the rocking radius at the time of the speed change operation, and both the input disks 2 and 2 and the both output disks 5, 5 Has little effect on the change in the transmission ratio between (and can be neglected or remain within an easily modifiable range).

  Whether the first example shown in FIGS. 3 to 4 or the second example shown in FIGS. 5 to 10, the power rollers around the roller support shafts 12 and 12 a are used in the conventional structure. Due to the structure of each of the radial needle bearings 20 and 20a for rotatably supporting the 6 and 6a, the following problems may occur. That is, each of the radial needle bearings 20 and 20a is provided with a plurality of needles 23 and 23 in the cages 24 and 24a in order to keep resistance (dynamic torque) against the rotation of the power rollers 6 and 6a low. Therefore, the rolling surfaces of the adjacent needles 23 and 23 are prevented from rubbing with each other.

  In order to suppress vibration and noise associated with the operation of the needle bearings 20 and 20a having such a structure, positioning of the retainers 24 and 24a in the radial direction is attempted, and the power rollers 6 and 6a are operated at high speed. It is necessary to prevent the cages 24 and 24a from being greatly displaced in the radial direction even when they are rotated. For this reason, conventionally, as shown in FIG. 11, the outer diameter D of the retainer 24 is slightly smaller than the inner diameter R of the center hole 19 of the power roller 6. Positioning in the radial direction of the retainer 24 has been achieved by a so-called outer ring guide structure in which the inner peripheral surface is closely opposed to each other through a minute gap 32.

  If the elastic deformation amount and temperature rise amount of the power roller 6 during operation of the toroidal type continuously variable transmission are limited (if they are small), the diameter of the cage 24 can be increased with the outer ring guide structure as described above. There is no particular problem with positioning in the direction. However, during operation of the toroidal-type continuously variable transmission, the power roller 6 starts from the stop state shown in FIG. 12A based on the large thrust load generated by the pressing device 26 (see FIG. 3). Like the driving state exaggerated in (B), the shape seen from the axial direction is elastically deformed in an elliptical direction. Then, based on such elastic deformation, there is a possibility that the retainer 24 swings around, or the outer peripheral surface of the retainer 24 and the inner peripheral surface of the center hole 19 are strongly rubbed (collised). When such whirling or rubbing occurs, the rotational resistance of the cage 24 and, consequently, the dynamic torque of the power roller 6 increases significantly. As a result, not only the transmission efficiency of the toroidal-type continuously variable transmission is lowered, but also a serious failure such as seizure occurs in a remarkable case. In order to prevent the swirling and rubbing, the difference between the outer diameter D of the cage 24 and the inner diameter R of the center hole 19 is increased (RD), so that the toroidal continuously variable transmission has a large torque. Even when the power roller 6 is most elastically deformed, the outer peripheral surface of the retainer 24 and the inner peripheral surface of the central hole 19 are opposed to each other with a gap over the entire periphery. It is possible to do. However, when such a structure is adopted, the radial positioning of the cage 24 is not necessarily performed sufficiently, and the cage 24 is likely to vibrate with the operation of the toroidal continuously variable transmission.

  During operation of the toroidal continuously variable transmission, torque is transmitted at the rolling contact portion (traction portion) between the peripheral surface of the power roller 6 and the inner surface of each of the disks 2 and 5 (see FIG. 3). The temperature (surface temperature) of the power roller 6 increases. That is, the peripheral surface of the power roller 6 and the inner surface of each of the disks 2 and 5 are closely opposed to each other through a minute gap of about 1 μm, and the minute gap is brought into rolling contact with a thin film of traction oil. The traction unit. When the toroidal continuously variable transmission is operated, a large torque is generated between the power rollers 6 and the axial side surfaces of the disks 2 and 5 based on the shearing force generated in the thin film of traction oil existing in the traction section. To communicate. During operation of such a toroidal-type continuously variable transmission, inevitable spin slip occurs in each traction portion as the disks 2 and 5 rotate, and the direction of the contact ellipse changes. For this reason, during the operation of the toroidal type continuously variable transmission, the amount of heat generated in the traction section is considerably increased, and the temperature of the power roller 6 is also significantly increased. As the temperature of the power roller 6 rises, the temperature of the outer ring raceway 22 that is the inner peripheral surface of the center hole 19 of the power roller 6 rises. When the temperature of the outer ring raceway 22 rises, it becomes difficult to ensure the rolling fatigue life of the radial needle bearing 20 provided between the outer ring raceway 22 and the inner ring raceway 21 that is the outer peripheral surface of the roller support shaft 12. This is disadvantageous in terms of ensuring the durability of the toroidal continuously variable transmission. The temperature rise of the outer ring raceway 22 can be suppressed to some extent by circulating traction oil functioning as a coolant (coolant) through the center hole 19 of the power roller 6. However, in the case where the radial positioning of the cage 24 is performed by an outer ring guide that causes the outer circumferential surface of the cage 24 and the outer ring raceway 22 to face each other through a small gap 32 as shown in FIG. In the center hole 19, the amount of traction oil passing through the outer diameter side of the cage 24 is smaller than the amount of traction oil passing through the inner diameter side, and the outer ring raceway 22 can be sufficiently cooled. There is no possibility.

JP 2003-214516 A JP 2007-315595 A JP 2008-25821 A JP 2008-275088 A JP 2004-169719 A

  In view of the circumstances as described above, the present invention can sufficiently position the radial direction of the cage constituting the radial needle bearing for supporting each power roller, and also when transmitting a large torque. The durability of the toroidal continuously variable transmission can be ensured by suppressing an increase in the temperature of the outer ring raceway of each radial needle bearing, which is the inner peripheral surface of each power roller, while suppressing an increase in the rotational resistance of the cage. It was invented to realize an easy structure.

A toroidal continuously variable transmission according to the present invention includes at least a pair of disks, a plurality of support members, the same number of roller support shafts and power rollers as the support members, and the same number of sets of radial needle bearings and thrusts. A rolling bearing and a pressing device are provided.
Each of these disks is supported concentrically with each other in such a manner that relative rotation is possible with the respective axial side surfaces facing each other, each of which is a toroidal curved surface having an arc cross section.
Each support member includes a pair of tilting shafts provided concentrically with each other at both ends. Then, with respect to the axial direction, swing displacements about the respective tilting shafts that are twisted with respect to the central axis of each disk are provided at a plurality of locations in the circumferential direction between the axial side surfaces of each disk. It is provided freely.
The roller support shafts are provided so as to protrude in the inward direction with respect to the radial direction of the discs from the intermediate portions of the trunnions with respect to the axial direction of the tilt shafts.
Each of the power rollers is rotatably supported around each of the roller support shafts by a part of each of the support members, and each peripheral surface having a spherical convex surface is provided on one axial side surface of each of the disks. It is in contact.
Each radial needle bearing includes a plurality of needles and a cage for holding the needles. The rolling surfaces of these needles are in rolling contact with the outer ring raceway provided on the inner peripheral surface of each power roller and the inner ring raceway provided on the outer peripheral surface of each roller support shaft.
Further, each thrust rolling bearing is formed on an outer ring raceway formed on the inner side surface of the outer ring supported on the inner side surface of each trunnion so as to be capable of axial displacement of each disk, and on the outer side surface of each power roller. A plurality of rolling elements are provided between the inner ring raceway and the inner ring raceway.
Further, the pressing device presses the disks in a direction approaching each other.

  In particular, in the toroidal-type continuously variable transmission of the present invention, each of the cages constituting each of the radial needle bearings includes an inner ring raceway provided on each of the inner peripheral surface and the outer peripheral surface of each of the roller support shafts. Each of the radial positions is regulated by the inner ring guides that are closely opposed to each other. Furthermore, the difference between the inner diameter of the center hole of each power roller and the outer diameter of each cage in the non-transmission state of power is determined from the maximum deformation amount of the center hole of each power roller based on power transmission. It is also bigger.

  When carrying out the present invention, for example, as in the invention described in claim 2, each of the roller support shafts is an eccentric shaft in which the base half portion and the front half portion are eccentric from each other. In addition, the base half of each roller support shaft is supported inside a support hole formed in the intermediate portion of each trunnion via a swing support radial bearing so as to be swingable and displaceable. In addition, the outer ring constituting each thrust rolling bearing is externally fitted and supported on the base end side portion of the front half of each roller support shaft. Further, a second thrust bearing is provided between the outer side surface of each outer ring and the inner side surface of each trunnion to allow displacement of each outer ring in the axial direction of each disk. The invention described in claim 2 corresponds to the case where the present invention is applied to the first example of the conventional structure described in FIGS.

  Alternatively, for example, as in the invention described in claim 3, each trunnion exists between the respective tilting shafts provided for each trunnion, and at least relates to the radial direction of each disk. A support beam portion having a cylindrical convex surface whose inner side surface has a central axis that is parallel to the central axes of the two tilt axes and that is present outside the central axes of the two tilt axes in the radial direction of each disk. It shall have. And the recessed part provided in the outer surface of each said outer ring | wheel which comprises each said thrust rolling bearing and the cylindrical convex surface of each said support beam part are engaged. The invention described in claim 3 corresponds to the case where the present invention is applied to the second example of the conventional structure described in FIGS.

According to the toroidal-type continuously variable transmission of the present invention configured as described above, the radial positioning of each cage constituting each radial needle bearing for supporting each power roller can be sufficiently achieved, and the large When transmitting torque, the increase in rotational resistance of each of these cages can be suppressed, and the temperature increase of the outer ring raceway of each of the radial needle bearings, which is the inner peripheral surface of each of the power rollers, can be suppressed. It is possible to realize a structure that can easily ensure the rolling fatigue life of the radial needle bearing and thus the durability of the toroidal type continuously variable transmission.
That is, when a large torque is transmitted by the toroidal-type continuously variable transmission, the pressing device presses each disk in a direction approaching each other with a large force, and each of the power rollers has an elliptical shape when viewed in the axial direction. It is elastically deformed into a state. Even in this case, the roller support shafts inserted through the center holes of the power rollers are hardly elastically deformed. Therefore, even when the difference between the inner diameter of each of these cages and the outer diameter of each of the roller support shafts is kept small in order to sufficiently suppress the radial shaking of each of the cages, the cages will not shake. It can be prevented that the inner peripheral surface of each of these cages and the outer peripheral surface of each of these roller support shafts rub against each other.
Further, it is not necessary to bring the outer peripheral surface of each retainer close to the inner peripheral surface of the center hole of each power roller for positioning in the radial direction of each retainer. For this reason, even if the center holes of these power rollers are elastically deformed with a large torque transmission, the cages are swung around, or the inner peripheral surfaces of the center holes and the outer peripheral surfaces of the cages are It can prevent rubbing. As a result, as described above, each cage can be sufficiently positioned in the radial direction, and an increase in rotational resistance of each cage can be suppressed even when a large torque is transmitted.

  Further, an annular gap having a large width in the radial direction is interposed between the inner peripheral surface of each center hole and the outer peripheral surface of each retainer, so that it passes through the outer diameter side of each retainer. A sufficient amount of traction oil can be secured. As a result, the outer ring raceway of each radial needle bearing provided on the inner peripheral surface of each center hole can be sufficiently cooled, and the rolling fatigue life of each radial needle bearing can be increased. It is easy to ensure durability.

The fragmentary sectional view which shows one example of embodiment of this invention. 1 is an end view showing the positional relationship in the radial direction among the roller support shaft, the cage, and the power roller when viewed from below in FIG. 1 in a torque non-transmission state (A) and a large torque transmission state (B). . Sectional drawing which shows the 1st example of a conventional structure. FIG. 4 is a cross-sectional view taken along the line aa in FIG. 3. The perspective view which looked at the trunnion which supported the power roller via the thrust ball bearing which shows the 2nd example of the conventional structure from the radial direction outer side of each disk. Similarly, the front view shown in the state seen from the circumferential direction of the disk. The top view seen from the upper part of FIG. The side view seen from the right side of FIG. Bb sectional drawing of FIG. Cc sectional drawing of FIG. The fragmentary sectional view for demonstrating the problem of conventional structure. Sectional drawing which similarly shows the positional relationship regarding the radial direction of a roller support shaft, a holder | retainer, and a power roller in the state seen from the downward direction of FIG. 11 in the torque non-transmission state (A) and the transmission state of a big torque.

  1 and 2 show an example of an embodiment of the present invention. The feature of the present invention including this example is that the radial positions of the cages 24b constituting the radial needle bearings 20b for rotatably supporting the power rollers 6 around the roller support shafts 12 are determined. This is because the inner ring guide is used. The structure and operation of the other parts are known toroidal types including the first example of the conventional structure shown in FIGS. 3 to 4 or the second example of the conventional structure shown in FIGS. Since it is the same as the continuously variable transmission, overlapping illustrations and descriptions will be omitted or simplified, and the following description will focus on the features of this example.

  A so-called inner ring guide in which the radial positions of the cages 24b constituting the radial needle bearings 20b are opposed to each other with the inner circumferential surface and the outer circumferential surface of the roller support shaft 12 in close proximity via a minute gap 32a. Respectively. That is, the inner diameter r of each retainer 24b is slightly larger than the outer diameter d of each roller support shaft 12 (r> d), so that each retainer 24b is placed around each roller support shaft 12. Are arranged in a state of being freely rotatable and suppressing displacement in the radial direction.

In contrast, the inner diameter R ₁ of the center hole 19 of the power rollers 6, is sufficiently larger than said outer diameter D ₁ of the respective retainer 24b. Specifically, the difference “R ₁ −D ₁ ” between the inner diameter R ₁ of the center hole 19 of each of the power rollers 6 and the outer diameter D ₁ of each of the retainers 24 b in the non-transmission state of the power, The maximum deformation amount δ of the center hole of each power roller 6 based on transmission is set larger.

According to the toroidal type continuously variable transmission of the present example configured as described above, each of the radial needle bearings 20b for supporting the power rollers 6 around the roller support shafts 12 is provided. Positioning of the cage 24b in the radial direction can be sufficiently achieved, and even when a large torque is transmitted, an increase in rotational resistance of each of the cages 24b can be suppressed, and the outer ring raceway 21 of each radial needle bearing 20b. Thus, it is possible to realize a structure in which the rolling fatigue life of each of the radial needle bearings 20b and the durability of the toroidal type continuously variable transmission can be easily secured.
That is, when a large torque is transmitted by the toroidal type continuously variable transmission, the pressing device 26 presses the disks 2 and 5 (see FIG. 3) in a direction approaching each other with a large force. As a result, the end face shape of the center hole 19 of each power roller 6 was a perfect circle as shown in FIG. 2A when torque was not transmitted. It is elastically deformed into an ellipse as shown in B). Even in this case, the roller support shafts 12 inserted through the center holes 19 of the power rollers 6 are hardly elastically deformed.

Accordingly, the difference “rd” between the inner diameter r of each of the cages 24b and the outer diameter d of the roller support shafts 12 is slightly suppressed in order to sufficiently restrain the cages 24b from shaking in the radial direction. Even in this case, it is possible to prevent each of the cages 24b from swinging around or from rubbing the outer peripheral surface of each of the roller support shafts 12 with the inner peripheral surface of each of the cages 24b.
The positioning of each cage 24b in the radial direction can be achieved only by making the inner circumferential surface of each cage 24b and the outer circumferential surface of each roller support shaft 12 close to each other, and the outer circumference of each cage 24b. It is not necessary to bring the surface close to the inner peripheral surface of the center hole 19 of each power roller 6. For this reason, even if the center hole 19 of each of the power rollers 6 is elastically deformed with a large torque transmission, each of the cages 24b swings around, or the inner peripheral surface of each of the center holes 19 and each of the cages 24b. There is no rubbing with the outer peripheral surface.
As a result, as described above, each of the cages 24b can be sufficiently positioned in the radial direction, and an increase in rotational resistance of the cages 24b can be suppressed even when a large torque is transmitted.

  Further, the positioning of each cage 24 in the radial direction is performed by an inner ring guide that brings the inner circumferential surface of each cage 24 and the outer circumferential surface of each roller support shaft 12 close to each other via a minute gap 32a. Therefore, regardless of the elastic deformation of each power roller 6 accompanying the operation of the toroidal continuously variable transmission, the space between the inner peripheral surface of the center hole 19 of each power roller 6 and the outer peripheral surface of each retainer 24b. In addition, an annular gap having a sufficiently large width in the radial direction can be interposed. Accordingly, a sufficient amount of traction oil passing through the outer diameter side of each retainer 24 among each center hole 19 can be secured, and the outer ring raceway 22 portion, which is the inner peripheral surface of each center hole 19, can be cooled. Can do enough. As a result, the temperature rise of the rolling contact portion of each radial needle bearing 20b including each outer ring raceway 22 can be suppressed, and the rolling fatigue life of each radial needle bearing 20b can be easily secured. The toroidal continuously variable transmission It is easy to ensure the durability.

  The present invention can be implemented not only in a structure that can be implemented by a toroidal type continuously variable transmission alone, but also in a continuously variable transmission that can realize a large gear ratio by combining a toroidal type continuously variable transmission and a planetary gear type transmission. In addition, not only the half-toroidal continuously variable transmission as shown in the figure but also the full toroidal toroidal continuously variable transmission that can be implemented with a full toroidal toroidal continuously variable transmission, each power The support member for rotatably supporting the roller is a carrier instead of the trunnion.

DESCRIPTION OF SYMBOLS 1 Input rotating shaft 2 Input disk 3 Output cylinder 4 Output gear 5 Output disk 6, 6a Power roller 7, 7a, 7b Trunnion 8, 8a, 8b Tilt axis 9 Support beam part 10 Support plate 11, 11a, 11b Radial bearing 12 , 12a Roller support shaft 13, 13a Thrust ball bearing 14 Thrust needle bearing 15 Inner ring raceway 16, 16a Outer ring 17 Outer ring raceway 18 Ball 19 Center hole 20, 20a, 20b Radial needle bearing 21 Inner ring raceway 22 Outer ring raceway 23 Needles 24, 24a, 24b Cage 25 Drive shaft 26 Press device 27 Actuator 28 Cylindrical convex surface 29 Support beam portion 30 Recess portion 31 Step surface 32, 32a Minute gap

Claims (3)

At least a pair of disks, a plurality of support members, each of which includes the same number of roller support shafts and power rollers as each of the support members, the same number of sets of radial needle bearings and thrust rolling bearings, and a pressing device,
Each of these disks is supported to be capable of relative rotation concentrically with each other in a state in which each side surface in the axial direction is a toroidal curved surface having an arc cross section.
Each of the supporting members includes a pair of tilting shafts provided concentrically with each other at both ends, and at a plurality of locations in the circumferential direction between the axial side surfaces of the disks in the axial direction. Oscillating displacement about each tilting shaft that is in a twisted position with respect to the central axis of each disk is freely provided,
Each of the roller support shafts is provided in a state of projecting in a radial direction of each of the disks from a part of each of the support members with respect to the axial direction of each of the tilt shafts.
Each of the power rollers is formed in an annular shape having a circular center hole, and is supported by a part of each of the support members so as to be rotatable around each of the roller support shafts. Are in contact with one axial side surface of each disk,
Each of the radial needle bearings includes a plurality of needles and a cage for holding the needles. The rolling surfaces of the needles are arranged on the inner peripheral surface of the power rollers and the roller support shafts. Rolling contact with the outer peripheral surface,
Each thrust rolling bearing includes an outer ring raceway formed on the inner side surface of the outer ring supported on the inner side surface of each trunnion so as to be capable of axial displacement of each disk, and an inner ring formed on the outer side surface of each power roller. A plurality of rolling elements are provided so as to be able to roll between the track,
In the toroidal-type continuously variable transmission that presses the disks in a direction approaching each other,
Each of the cages constituting each of the radial needle bearings regulates the radial position thereof by an inner ring guide that makes each inner peripheral surface and the outer peripheral surface of each of the roller support shafts face each other. The difference between the inner diameter of the center hole of each power roller and the outer diameter of each cage in the non-transmission state is larger than the maximum deformation amount of the center hole of each power roller based on power transmission. A toroidal-type continuously variable transmission.   Each of the roller support shafts is an eccentric shaft in which a base half and a front half are eccentric from each other, and the base half of each of the roller support shafts is formed at an intermediate portion of the trunnion as each of the support members. Inside the hole is supported so as to be swingable and displaceable via a swing support radial bearing, and the outer ring constituting each thrust rolling bearing is a proximal end portion of the front half of each roller support shaft. A second thrust bearing is provided between the outer side surface of each outer ring and the inner side surface of each trunnion to allow displacement of each outer ring in the axial direction of each disk. The toroidal continuously variable transmission according to claim 1.   Each trunnion exists between the respective tilting shafts provided in a pair for each trunnion, and at least the inner side surface in the radial direction of each disc is defined as the central axis of the two tilting shafts. The thrust rolling bearing comprises each of the thrust rolling bearings having a cylindrical convex surface having a central axis that is parallel and has a central axis that exists outside the central axis of the two tilting axes in the radial direction of each disk. The toroidal continuously variable transmission according to claim 1, wherein a concave portion provided on an outer surface of each outer ring and a cylindrical convex surface of each support beam portion are engaged.

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