JP6110215B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement in a toroidal type continuously variable transmission that is used as a transmission for an automobile or a transmission for adjusting the operating speed of various industrial machines such as a pump.

  The use of a 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. FIG. 3 shows a first example of a toroidal-type continuously variable transmission described in these patent documents and widely known in the past. In the case of the first example of this conventional structure, a pair of input-side disks 2a and 2b are disposed around the portions near both ends of the input rotating shaft 1, with the inner surfaces each being a toroidal curved surface facing each other. It is supported via splines 20, 20 so as to be able to move far and away, and to rotate in synchronization with the input rotary shaft 1. An output cylinder 3 is supported around the intermediate portion of the input rotary shaft 1 so as to be able to rotate relative 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 side disks 5, 5 are connected to both ends in the axial direction by spline engagement. The rotation synchronized with 3 is supported. In this state, the inner side surfaces of the output side disks 5 and 5, each of which is a toroidal curved surface, are opposed to the inner side surfaces of the input side disks 2 a and 2 b.

  Further, a plurality of power rollers 6 and 6 each having a spherical convex surface are sandwiched between the input disks 2 a and 2 b and the output disks 5 and 5. The power rollers 6 and 6 are rotatably supported by the trunnions 7 and 7, respectively, and rotate with the rotation of the two input side disks 2a and 2b. Power is transmitted to both output side disks 5 and 5. That is, when the toroidal-type continuously variable transmission is operated, the drive shaft 8 rotates one (left side in FIG. 3) of the input side disk 2a via a pressing device 9 (the structure shown is a loading cam type pressing device). To drive. As a result, the pair of input-side disks 2a and 2b supported at both ends of the input rotation shaft 1 rotate synchronously while being pressed in a direction approaching each other. Then, this rotation is transmitted to the output side disks 5 and 5 through the power rollers 6 and 6 and is taken out from the output gear 4. The trunnions 7 and 7 correspond to the support members described in the claims.

  Further, preload springs 10a and 10b are provided at positions where both the input side disks 2a and 2b are sandwiched from both sides in the axial direction in the vicinity of both ends of the input rotary shaft 1, respectively. Even when the pressing device 9 is not in operation (when the drive shaft 8 is stopped), the peripheral surfaces of the power rollers 6 and 6 and the inner surfaces of the input side and output side disks 2a, 2b and 5 are provided. The surface pressure of the rolling contact part (traction part) is secured to the minimum necessary. Therefore, these rolling contact portions start power transmission without causing excessive slip immediately after the start of operation of the toroidal continuously variable transmission. The elasticity for securing the minimum necessary surface pressure is obtained by a preload spring 10 a disposed on the inner diameter side of the pressing device 9. The preload spring 10b disposed between the loading nut 11 screwed to the tip end of the input rotary shaft 1 and the outer surface of the input side disk 2b alleviates the impact applied when the pressing device 9 is suddenly operated. It can be omitted. When it is provided, it has a sufficiently large elasticity (so as not to be completely crushed even when a large torque is transmitted).

  In the case of the toroidal type continuously variable transmission as described above, the work of adjusting the elasticity of the preload spring 10a for ensuring the minimum surface pressure is troublesome. That is, in the case of the first example of the conventional structure, it is necessary to adjust the elasticity of the preload spring 10a by changing the tightening amount of the loading nut 11 screwed to the tip end portion of the input rotary shaft 1. It is. On the other hand, Patent Documents 6 to 7 describe a structure using a locking ring called a cotter instead of a loading nut. 4 to 7 show a second example of a conventional structure incorporating such a locking ring. In the case of the second example of this conventional structure, a spline hole 12 is formed at the center of the input side disk 2b, and the spline hole 12 and a spline shaft portion 13 formed on the outer peripheral surface of the input rotary shaft 1a. Is engaged. In addition, a locking groove 14 is formed over the entire circumference on the outer peripheral surface of the tip end portion of the input rotary shaft 1a at a portion that is axially removed from the spline shaft portion 13, and a plurality of locking grooves 14 are formed in the locking groove 14. The radially inner half of the locking ring 15 made up of (2 to 4) partial arc-shaped elements is locked. Then, the radially outer end portion of the inner side surface (the left side surface in FIGS. 4 to 5) of the locking ring 15 is brought into contact with the radially inner end portion of the outer side surface of the input side disk 2b. When the pressing device 9 (the illustrated structure is a hydraulic pressing device) is not in operation, the peripheral surfaces of the power rollers 6 and 6 (see FIG. 3) and the inner surfaces of the input and output disks 2a, 2b and 5a Adjustment of the elastic force of the disc spring 10a to ensure the minimum necessary surface pressure of the rolling contact portion is achieved by selecting the locking ring 15 having an appropriate axial thickness dimension. Further, a retaining ring 16 having an L-shaped cross section is fitted on the tip of the input rotating shaft 1a, and the inner peripheral surface of the retaining ring 16 is brought into contact with or in close proximity to the outer peripheral surface of the locking ring 15. The locking ring 15 (elements constituting the locking ring 15) is prevented from coming out of the locking groove 14. Such a retaining ring 16 prevents axial displacement by a retaining ring 17 that is engaged with the tip of the input rotary shaft 1a. With the configuration described above, the input disk 2b is supported on the input rotary shaft 1a so as to be able to rotate in synchronization with the input rotary shaft 1a. In the case of the second example of the conventional structure, the entire toroidal continuously variable transmission is reduced in size and weight by using an integral output side disk 5a. However, since the structure and operation of this portion are not related to the gist of the present invention, detailed description thereof is omitted.

  In the case of the toroidal type continuously variable transmission according to the second example of the conventional structure as described above, the input-side disk 2b on the distal end side is driven by the power rollers 6 based on the thrust generated by the pressing device 9 during operation. Based on the force received from 6, as shown in an exaggerated manner in FIG. 8, the portion near the outer diameter of the input side disk 2 b is elastically deformed in a direction (axial direction) approaching the locking ring 15 side. That is, the force applied to the input side disk 2b based on the thrust during operation is about several tens kN to hundreds tens kN (several tF to several tens tF) at the maximum during operation of the toroidal type continuously variable transmission. The amount of elastic deformation in the axial direction of the input-side disk 2b based on a large force is a comma number of mm (a few tenths of a millimeter) and cannot be ignored. When the input side disk 2b is elastically deformed in the axial direction in this way, there is a possibility that the outer side surface of the input side disk 2b and the inner side surface of the locking ring 15 are repeatedly contacted intermittently. In the case of the second example of the conventional structure, since the spline hole 12 is provided at the center of the input side disk 2b, the outer end edge of each female spline groove of the spline hole 12 (the right end in FIGS. 4 and 5). Edge) and the inner side surface of the locking ring 15 (left side surface in FIGS. 4 and 5) are repeatedly contacted and rubbed against each other, and the outer edge of each of the female spline grooves is There is a tendency to bite into the inner surface, and fretting wear may occur in the portion. In particular, the circumferential position at which the input side disk 2b is elastically deformed always changes as the portions pressed by the power rollers 6 and 6 change. For this reason, the frequency of the rubbing becomes considerably high (for example, hundreds of tens Hz), which is a severe condition in terms of occurrence of fretting wear. Such fretting wear may become a starting point of damage such as peeling, or the generated wear powder may contaminate the lubricating oil (traction oil), resulting in poor lubrication of each part.

JP 2003-214516 A JP 2007-315595 A JP 2008-25821 A JP 2008-275088 A JP 2004-169719 A JP 2000-205361 A JP 2009-041715 A

  In view of the circumstances as described above, the present invention provides an edge of a female spline groove of a spline hole provided at the center of the outer disk, and an engagement ring, regardless of the elastic deformation in the axial direction of the outer disk. The invention was invented to realize a structure capable of preventing fretting wear from occurring on one side surface.

A toroidal continuously variable transmission according to the present invention includes a rotating shaft, a pair of outer disks, an inner disk, a plurality of support members, the same number of power rollers as each of the support members, a pressing device, and a locking device. With a ring.
Of these, the rotating shaft is provided with a locking groove on the outer peripheral surface of the tip portion, and a spline shaft portion in a portion adjacent to the locking groove in the axial direction.
In addition, the both outer disks can freely rotate in synchronization with the rotating shaft at both ends of the rotating shaft in a state where the axial side surfaces of the outer disks are opposed to each other. One outer disk of the two outer disks is capable of axial displacement relative to the rotating shaft, and the other outer disk is similarly formed with a spline hole formed in the center of the other outer disk and the spline shaft. Each is supported by engaging the part.
In addition, the inner disk rotates relative to the rotating shaft around the middle portion of the rotating shaft, with both axial side surfaces having a circular arc cross section facing one axial side surface of the outer disks. It is supported freely, and is formed as a single unit or a pair of elements.
Further, each of the supporting members is pivoted at a position twisted with respect to the rotating shaft, and a plurality of each of the supporting members is disposed between the axial side surfaces of the inner disk and the axial side surfaces of the outer disks. Oscillating displacement around the center is freely provided.
Each of the power rollers is rotatably supported by each of the supporting members, and each circumferential surface having a spherical convex surface is formed on both sides in the axial direction of the inner disk and on one side in the axial direction of the outer disks. And abut.
The pressing device is provided between the rotating shaft and one outer disk of the two outer disks, and the one outer disk faces the other outer disk of the two outer disks. Press. As such a pressing device, a loading cam type or a hydraulic pressing device can be used.
In addition, the locking ring is configured by combining a plurality of (for example, 2 to 4) partial arc-shaped elements so as to form a ring shape as a whole, and the locking ring formed on the outer peripheral surface of the rotating shaft. Locked in the groove, one axial side surface of the locking ring (a portion exposed from the locking groove) is brought into contact with the other axial side surface of the other outer disk facing in the axial direction. This prevents the other outer disk from being displaced in a direction away from the one outer disk.

  Particularly, in the case of the toroidal continuously variable transmission according to the present invention, the axially adjacent one side surface of the locking ring and the other axially side surface of the other outer disk are adjacent to the radially outer side of the opening of the spline hole. A gap for preventing the axial one side surface of the locking ring from coming into contact with the edge of each female spline groove constituting the spline hole is provided between the engaging portion and the portion to be engaged.

In this case, for example, the gap is provided by forming a chamfered portion at the edge of the spline hole. This is preferably the case, the radial length of the chamfered portion of this, and the depth of each female spline grooves of the spline hole {of the inscribed circle of the tooth bottom (groove bottom) surface diameter, inscribed in the tooth crest It should be larger than 1/2 of the difference from the diameter of the circle.

Alternatively, as in the present invention, the gap is provided by forming a thinned portion in a range extending from a radial intermediate portion to an inner end portion of one axial end portion of the locking ring. As a result, the diameter of the inscribed circle (inner peripheral edge) of one end face in the axial direction of the locking ring is made larger than the diameter of the inscribed circle of the tooth bottom surface of the female spline groove.
When the present invention as described above is carried out, the outer diameter of the locking ring is preferably a toroidal curved surface having an arcuate cross section as in the invention described in claim 2. It is made smaller than the diameter of the small-diameter side edge on one side surface in the axial direction.

  According to the toroidal type continuously variable transmission of the present invention configured as described above, regardless of the elastic deformation in the axial direction of the outer disk, the edge of the female spline groove of the spline hole of the outer disk, and the locking ring It is possible to prevent fretting wear from occurring between the one side surface and the other side surface. That is, a gap is provided between one axial side surface of the locking ring and a portion of the other axial side surface of the outer disk adjacent to the radially outer side of the opening of the spline hole. As a result, even when the outer disk is elastically deformed in the axial direction based on the thrust generated by the pressing device, the one axial side surface of the locking ring and the end edge of the female spline groove are rubbed together. It is possible to prevent the edge from becoming a tendency to bite into one side surface in the axial direction, and to prevent the occurrence of significant fretting wear in the portion.

The figure (A) equivalent to the X section enlarged view of FIG. 4 which shows one example of the reference example regarding this invention, and the Y section enlarged view (B) of (A). The figure similar to FIG. 1 which shows an example of embodiment of this invention. Sectional drawing which shows the 1st example of a conventional structure. Sectional drawing which shows the 2nd example. Similarly, the X part enlarged view (A) of FIG. 4 and the Z part enlarged view (B) of (A). The perspective view which takes out and shows the input side disk of the front end side. Sectional drawing which shows the state of the engaging part of this input side disk of this front end side, and an input rotating shaft. The schematic diagram which exaggerates and shows the elastic deformation of this input side disk of the front end side.

[ Example of reference example ]
FIG. 1 shows an example of a reference example related to the present invention. The features of the toroidal type continuously variable transmission and continuously variable transmission of the present invention described later, including this reference example, are characterized by the elasticity of the input side disk 2c based on the thrust generated by the pressing device 9 (see FIGS. 3 and 4). Regardless of the deformation, the outer end edge (the right end edge in FIG. 1) of the female spline groove of the spline hole 12a formed at the center of the input side disk 2c and the inner side face (the left side face in FIG. 1) of the locking ring 15 It is in a structure to suppress the occurrence of fretting wear. Since the structure and operation of the other parts are the same as those of conventionally known toroidal type continuously variable transmissions including the structures shown in FIGS. 4 to 7 described above, illustration and explanation of equivalent parts are omitted or simplified. In the following, the description will focus on the features of this reference example .

In the case of this reference example , the outer end edge (opening edge on the outside in the axial direction) of the spline hole 12a of the input side disk 2c is subjected to shaving (chamfering), and a chamfered portion 18 is formed on the outer end edge. . The radial length L of the chamfered portion 18 is larger than the depth d of each female spline groove constituting the spline hole 12a (L> d), so that the inner surface of the locking ring 15 and the An annular gap 21 having a triangular cross-sectional shape is provided between the outer surface of the input side disk 2c and the portion adjacent to the radially outer side of the opening of the spline hole 12a. Accordingly, even when the input side disk 2c is elastically deformed in the axial direction based on the thrust generated by the pressing device 9 (see FIG. 5), the outer edge of the female spline groove of the spline hole 12a and the engagement This prevents the outer surface of the ring 15 from rubbing against the inner surface of the inner surface. In the illustrated example, the chamfering applied to the outer edge of the spline hole 12a is a C chamfer having a straight cross-sectional shape. However, if the radial direction length of the chamfered portion is larger than the depth of each female spline groove constituting the spline hole 12a, the chamfer may be an R chamfer having a partial arc shape in cross section. Of the outer side surface of the input side disk 2c, the portion between the outer peripheral edge of the chamfered portion 18 and the portion adjacent to the radially outer side of the chamfered portion 18 is smoothly continued so that the corner portion is eliminated. Things are preferable.

According to the toroidal continuously variable transmission of this reference example configured as described above, fretting wear occurs between the outer edge of the female spline groove of the spline hole 12a and the inner surface of the locking ring 15. Can be suppressed. That is, the chamfered portion 18 is provided at the outer end edge of the spline hole 12a, and the radially outer side of the opening portion of the spline hole 12a among the inner side surface of the locking ring 15 and the outer side surface of the input side disk 2c. The gap 21 is provided between adjacent portions. Therefore, even when the outer disk 2c is elastically deformed in the axial direction, the inner surface of the locking ring 15 and the outer edge of the female spline groove of the spline hole 12a rub against each other, and this outer edge is the inner surface. Can prevent the tendency to bite into. As a result, fretting wear can be prevented from occurring in the portion.

[1 Example Embodiment
FIG. 2 shows an example of an embodiment of the present invention corresponding to claims 1 and 2 . In the case of this example, the thinned portion described in the claims is formed in a range extending from the radial intermediate portion to the inner end portion of the inner end portion (left end portion in FIG. 2) of the locking ring 15a. On one side surface in the axial direction of the retaining ring 15a, an inclined surface portion 19 that is inclined in a direction toward the other side in the axial direction (the right side in FIG. 2) is provided. Then, the diameter D ₁₅ of the axial one side of an inscribed circle of the locking ring 15a (inner periphery), bottom land of the female spline grooves constituting the spline hole 12 of the input side disk 2b of the (tooth groove bottom) It is larger than the diameter D _{12 of the} inscribed circle (D ₁₅ > D ₁₂ ). As a result, the cross-sectional shape of the outer surface of the outer disk 2b is triangular and circular between the portion adjacent to the radially outer side of the opening of the spline hole 12 and the inner surface of the locking ring 15a. The gap 21a is provided.

In the case of the illustrated example, the cross-sectional shape of the inclined surface portion 19 is linear. However, the inclined surface portion (thickening portion) provided in the locking ring 15a has a cross-sectional shape if the diameter of the inscribed circle is larger than the diameter of the inscribed circle of the tooth bottom surface of each female spline groove of the spline hole 12. May be a convex curved surface or a concave curved surface having a partial arc shape, or a composite curved surface including a plurality of inclined surfaces.
Since the configuration and operation of the other parts are the same as in the above-described example of the reference example, illustration and explanation regarding the equivalent parts are omitted.

DESCRIPTION OF SYMBOLS 1, 1a Input rotary shaft 2a, 2b, 2c Input side disk 3 Output cylinder 4 Output gear 5, 5a Output side disk 6 Power roller 7 Trunnion 8 Drive shaft 9 Pressing device 10a, 10b Preload spring 11 Loading nut 12, 12a Spline hole 13 Spline shaft portion 14 Locking groove 15 Locking ring 16 Retaining ring 17 Retaining ring 18 Chamfered portion 19 Inclined surface portion 20 Ball spline 21, 21a Clearance

Claims (2)

A rotation shaft, a pair of outer disks, an inner disk, a plurality of support members, the same number of power rollers as each of the support members, a pressing device, and a locking ring;
Among these, the rotating shaft is provided with a locking groove on the outer peripheral surface of the tip portion, and a spline shaft portion in a portion adjacent to the locking groove in the axial direction,
The both outer disks can freely rotate in synchronism with the rotating shaft in a state in which the axial side surfaces of each of the outer disks face each other in an arc shape, and one of the outer disks The outer disk is capable of axial relative displacement with respect to the rotating shaft, and the other outer disk is engaged with a spline hole formed in the center of the other outer disk and the spline shaft. It is supported by each rotating shaft,
The inner disk can freely rotate relative to the rotating shaft around the middle portion of the rotating shaft, with both axial side surfaces having a circular arc cross section facing one axial side surface of the outer disks. A unitary or supported pair of elements that are supported,
Each of the supporting members is centered on a pivot that is twisted with respect to the rotating shaft, and a plurality of each of the supporting members is located between the axially opposite side surfaces of the inner disk and the axially one side surface of the outer disks. The rocking displacement
Each of the power rollers is rotatably supported by each of the support members, and has a spherical convex surface that is in contact with both axial side surfaces of the inner disk and one axial side surface of the outer disks. And
The pressing device is provided between the rotating shaft and the one outer disk, and presses the one outer disk toward the other outer disk.
The locking ring is locked in the locking groove, and one side surface in the axial direction thereof is brought into contact with the other side surface in the axial direction of the other outer disk facing in the axial direction. In a toroidal type continuously variable transmission that prevents displacement in a direction away from the one outer disk,
Axial direction of the locking ring between one axial side surface of the locking ring and a portion of the other axial side surface of the other outer disk adjacent to the radially outer side of the opening of the spline hole. There is a gap to prevent one side and the edge of each female spline groove that makes up this spline hole from contacting ,
The gap is provided by forming a thinned portion in a range extending from a radial intermediate portion to an inner end portion of one end portion in the axial direction of the locking ring. A toroidal continuously variable transmission characterized in that a diameter of a contact circle is larger than a diameter of an inscribed circle of a tooth bottom surface of each female spline groove of the spline hole . 2. The toroidal stepless device according to claim 1, wherein an outer diameter of the locking ring is a toroidal curved surface having a circular arc cross section, and is smaller than a diameter of a small-diameter side edge of one side surface in the axial direction of the other outer disk. transmission.

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