JP4174712B2 - Induction hardening method for trunnion of toroidal type continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for induction hardening of a trunnion of a toroidal continuously variable transmission (CVT) that can be used as a transmission for automobiles and various industrial machines.
[0002]
[Prior art]
The use of a toroidal type continuously variable transmission as schematically shown in FIGS. 7 and 8 is partially implemented as a transmission for an automobile. This toroidal-type continuously variable transmission supports an input side disk 2 that is a first disk concentrically with the input shaft 1, and a second disk is disposed at the end of the output shaft 3 that is disposed concentrically with the input shaft 1. The output side disk 4 is fixed. Inside the casing containing the toroidal-type continuously variable transmission, trunnions 6 and 6 are provided that swing around pivots 5 and 5 that are twisted with respect to the input shaft 1 and the output shaft 3. A power roller 11 is rotatably supported by each trunnion 6, 6, and each power roller 11, 11 is sandwiched between both the input side and output side disks 2, 4.
[0003]
The cross sections of the inner side surfaces 2a and 4a facing each other of the input and output side disks 2 and 4 each form a concave surface obtained by rotating an arc centering on the pivot 5 or a curve close to such an arc. ing. And the peripheral surface 11a, 11a of each power roller 11, 11 formed in the spherical convex surface is contact | abutted to each inner surface 2a, 4a.
[0004]
Between the input shaft 1 and the input side disk 2, a loading cam type pressing device 12 is provided. The pressing device 12 elastically presses the input side disk 2 toward the output side disk 4. The pressing device 12 includes a cam plate 13 that rotates together with the input shaft 1 and a plurality of (for example, four) rollers 15 and 15 held by a cage 14. In addition, a cam surface 16 that is a concavo-convex surface is formed on one side surface (the left side surface in FIGS. 7 and 8) of the cam plate 13, and the outer surface (see FIGS. 7 and 8) of the input side disk 2 is formed. A similar cam surface 17 is also formed on the right side surface of FIG. The plurality of rollers 15 and 15 are supported so as to be rotatable about an axis extending in the radial direction with respect to the input shaft 1.
[0005]
In the toroidal type continuously variable transmission having such a configuration, when the input shaft 1 is rotated, the cam plate 13 is rotated along with the rotation of the input shaft 1, and the plurality of rollers 15, 15 are connected to the input side disk by the cam surface 16. 2 is pressed by the cam surface 17 provided on the outer side surface of the head. As a result, the input-side disk 2 is pressed against the plurality of power rollers 11, 11, and at the same time, based on the pressing between the pair of cam surfaces 16, 17 and the rolling surfaces of the plurality of rollers 15, 15. The input side disk 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the power rollers 11 and 11, and the output shaft 3 fixed to the output side disk 4 rotates.
[0006]
When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is performed between the input shaft 1 and the output shaft 3, the trunnions 6 and 6 are swung around the pivot shafts 5 and 5. As shown in FIG. 7, the peripheral surfaces 11a and 11a of the power rollers 11 and 11 are arranged near the center of the inner surface 2a of the input side disk 2 and the outer periphery of the inner side surface 4a of the output side disk 4, respectively. The displacement shafts 9 and 9 are inclined so as to abut each other.
[0007]
On the other hand, when the speed is increased, the trunnions 6 and 6 are swung so that the peripheral surfaces 11a and 11a of the power rollers 11 and 11 have the inner surface 2a of the input side disk 2 as shown in FIG. Each of the displacement shafts 9 and 9 is inclined so as to come into contact with the outer peripheral portion and the central portion of the inner side surface 4 a of the output side disk 4. If the inclination angle of each of the displacement shafts 9 and 9 is set intermediate between those shown in FIGS. 7 and 8, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.
[0008]
FIG. 9 and FIG. 10 show an example of a more specific toroidal continuously variable transmission. In addition, about the structural member which is common in FIG.7 and FIG.8, the same code | symbol is attached | subjected below and the detailed description or illustration is abbreviate | omitted.
As shown in FIG. 9, the input shaft 1 is rotatably supported inside the casing 101. A circular transmission shaft 103 is supported on the outer periphery of the input shaft 1. In this case, the transmission shaft 103 is disposed concentrically with the input shaft 1 and can rotate with respect to the input shaft 1.
[0009]
The first and second input side disks 2 and 2 are respectively supported by ball splines 96 at both ends of the transmission shaft 103. In this case, the first and second input side disks 2 and 2 are concentrically arranged with their inner side surfaces 2a and 2a facing each other, and can rotate in synchronization with each other inside the casing 101. .
[0010]
Around the intermediate portion of the transmission shaft 103, first and second output side disks 4, 4 are supported via a sleeve 109. An output gear 110 is integrally provided on the outer peripheral surface of the intermediate portion of the sleeve 109. The output gear 110 is disposed concentrically with the transmission shaft 103 and has an inner diameter larger than the outer diameter of the transmission shaft 103. The output gear 110 is rotatably supported by a support wall 111 provided in the casing 101 via a pair of rolling bearings 112.
[0011]
The first and second output side disks 4 and 4 are splined to both ends of the sleeve 109. In this case, the output side disks 4 and 4 are arranged with their inner side surfaces 4a and 4a facing in opposite directions. Accordingly, the input side disk 2 and the output side disk 4 have their inner side surfaces 2a, 4a facing each other.
[0012]
As shown in FIG. 10, a pair of yokes 113a and 113b are supported inside the casing 101 and laterally of the output side disks 4 and 4 with both the disks 4 and 4 sandwiched from both sides. Yes. The pair of yokes 113a and 113b are formed in a rectangular shape by pressing or forging a metal such as steel. In order to support the pivots 5 provided at both ends of the trunnion 6 to be described later in a swingable manner, circular support holes 118 are provided at the four corners of the yokes 113a and 113b, and the width direction of the yokes 113a and 113b. A circular locking hole 119 is provided at the center of the.
[0013]
The pair of yokes 113a and 113b are supported so as to be slightly displaceable by support posts 20a and 20b formed on portions of the inner surface of the casing 101 facing each other. These support posts 20a and 20b are respectively provided so as to face the first cavity 21 and the second cavity 22 between the inner side surface 2a of the input side disk 2 and the inner side surface 4a of the output side disk 4, respectively. Yes. The post 20 a is provided with a tilt stopper 150 that regulates the tilt amount of the trunnion 6.
[0014]
Accordingly, the yokes 113 a and 113 b are supported by the support posts 20 a and 20 b, and one end thereof faces the outer peripheral portion of the first cavity 21 and the other end faces the outer peripheral portion of the second cavity 22. is doing.
[0015]
Since the first and second cavities 21 and 22 have the same structure, only the first cavity 21 will be described below.
[0016]
The first cavity 21 is provided with a pair of trunnions 6. Concentric shafts 5 are provided concentrically at both ends of the trunnion 6, and these pivots 5 are supported by one end portions of a pair of yokes 113a and 113b so as to be swingable and axially displaceable. That is, the pivot 5 is supported by the radial needle bearing 26 inside the support hole 118 formed at one end of the yokes 113a and 113b. The radial needle bearing 26 includes an outer ring 27 whose outer peripheral surface is a spherical convex surface and whose inner peripheral surface is a cylindrical surface, and a plurality of needles 28.
[0017]
A circular hole 30 is provided in each intermediate portion of the trunnion 6. A displacement shaft 31 is supported in each circular hole 30. Each of the displacement shafts 31 includes a support shaft portion 33 and a pivot shaft portion 34 that are parallel to each other and eccentric. Among these, the support shaft portion 33 is supported inside the circular hole 30 via a radial needle bearing 35. The power roller 11 is supported around the pivot shaft 34 via another radial needle bearing 38.
[0018]
A pair of displacement shafts 31 provided for each of the first and second cavities 21 and 22 are 180 degrees opposite to the input shaft 1 and the transmission shaft 103 for each of the first and second cavities 21 and 22. Is located. Further, the directions in which the respective pivot shaft portions 34 of the displacement shaft 31 are eccentric with respect to the respective support shaft portions 33 are the same with respect to the rotation directions of the input side disks 2 and 2 and the output side disks 4 and 4. . The eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 1 is disposed. Therefore, the power roller 11 is supported so that it can be slightly displaced along the longitudinal direction of the input shaft 1 and the transmission shaft 103. As a result, the power roller 11 tends to be displaced in the axial direction of the input shaft 1 and the transmission shaft 103 due to a variation in the amount of elastic deformation of the constituent members based on a variation in the torque transmitted by the toroidal continuously variable transmission. Even in this case, an excessive force is not applied to the component member, and the displacement can be absorbed.
[0019]
In addition, a thrust ball bearing 39 and a thrust bearing 40 such as a slide bearing or a needle bearing are provided between the outer peripheral surface of the power roller 11 and the inner peripheral surface of the trunnion 6 in order from the large end surface. It has been. Among these, the thrust ball bearing 39 allows rotation of the power roller 11 while supporting a load in the thrust direction applied to the power roller 11. The thrust bearing 40 allows the pivot shaft 34 and the outer ring 41 to swing around the support shaft 33 while supporting a thrust load applied to the outer ring 41 of the thrust ball bearing 39 from the power roller 11. .
[0020]
A drive rod 42 is coupled to one end of the trunnion 6. A drive piston 43 is fixed to the outer peripheral surface of the intermediate portion of these drive rods 42. The drive piston 43 is oil-tightly fitted in the drive cylinder 44. The drive piston 43 constitutes an actuator for displacing the trunnion 5 in the axial direction.
[0021]
As shown in FIG. 9, a loading cam type pressing device 45 is provided between the input shaft 1 and one input side disk 2. The pressing device 45 includes a cam plate 46 and a plurality of rollers 48, and rotates one input-side disk 2 while pressing it toward the other input-side disk 2 based on the rotation of the input shaft 1. In this case, the cam plate 46 is spline-engaged with the intermediate portion of the input shaft 1, supported in a state where displacement in the axial direction is prevented, and rotates together with the input shaft 1. The plurality of rollers 48 are held by a holder 47 so as to be freely rollable.
[0022]
During operation of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to one input side disk 2 via the pressing device 45, and the input side disk 2 and the other input side disk are transmitted. The disk 2 rotates in synchronization with each other. The rotation of the input side disks 2 and 2 is transmitted to the output side disks 4 and 4 via the power roller 11. The rotation of the output side disks 4 and 4 is taken out by the output gear 110.
[0023]
When the rotational speed ratio between the input shaft 1 and the output gear 110 is changed, a pair is provided corresponding to the first and second cavities 21 and 22 based on switching of control valves (not shown). The drive piston 43 thus moved is displaced by the same distance in the opposite directions for each of the cavities 21 and 22. Along with the displacement of these drive pistons 43, a total of four trunnions 6 are displaced in the opposite direction, and one power roller 11 is displaced downward and the other power roller 11 is displaced upward. As a result, the tangential force acting on the contact portion between the peripheral surface of each power roller 11 and the inner side surfaces 2a and 2a of the input side disks 2 and 2 and the inner side surfaces 4a and 4a of the output side disks 4 and 4 The direction of changes. As the direction of the force changes, the trunnion 6 swings in the reverse direction around the pivot shaft 5 pivotally supported by the yokes 113a and 113b. As a result, the contact position between the peripheral surface of the power roller 11 and the input side disks 2 and 2 and the output side disks 4 and 4 changes, and the rotational speed ratio between the input shaft 1 and the output gear 110 changes. .
[0024]
By the way, the trunnion 6 that rotatably supports the power roller 11 and tilts around the pivot shaft 5 receives a large load from the power roller 11, so that when it is baked, the fatigue fracture strength is lost. Therefore, induction hardening is generally performed only on the portion of the trunnion 6 that requires hardness (see, for example, Patent Document 1 and Patent Document 2).
[Patent Document 1]
Japanese Patent Laid-Open No. 11-132302 [Patent Document 2]
Japanese Patent Application Laid-Open No. 11-201250
[Problems to be solved by the invention]
The trunnion 6 has several functional surfaces that require hardness. As shown in FIG. 11, the portion of the trunnion 6 that requires hardness supports the pivot shaft 5 in a tiltable manner. This is a contact portion S1 between the transfer surface portion S2 of the radial needle bearing 26 and the tilt stopper 150.
[0026]
However, the transfer surface portion S2 of the radial needle bearing 26 and the contact portion S1 with the tilt stopper 150 are often close to each other in design, and as shown in FIG. 11, induction hardening of both S1 and S2 is performed. In many cases, the ranges overlap (in FIG. 11, the overlapping portion of both S1 and S2 is indicated by X). And in such a portion X where the induction hardening ranges overlap, annealing and induction quenching occur, and the durability of the trunnion 6 becomes a problem.
[0027]
The present invention has been made paying attention to the above circumstances, and is a toroidal type continuously variable transmission that can ensure the durability of a portion that requires hardness to a desired level even when the quenching ranges overlap . and to provide a high-frequency hardening method of the trunnion.
[0028]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention described in claim 1 is characterized in that the power roller sandwiched between the input side disk and the output side disk is rotatably supported, and the centers of the input side disk and the output side disk are supported. In the induction hardening method in which induction hardening is performed on a trunnion of a toroidal-type continuously variable transmission that tilts around a pivot that is twisted with respect to the shaft, the trunnion has a trunnion tilt amount around the pivot. A contact portion that contacts the tilt stopper for regulating; and a transfer surface portion of a radial needle bearing that pivotally supports the pivot so as to tilt, and the contact portion with the tilt stopper is induction hardened. after the process has been performed, the tempering is performed, after which induction hardening process is characterized in that it is facilities to the transfer surface of the radial needle bearing.
[0029]
In the invention described in claim 1, even if the quenching ranges are overlapped, the hardness of the transfer surface portion of the radial needle bearing can be ensured to a desired hardness, and the occurrence of quenching cracks can be prevented. Can be prevented.
[0030]
According to a second aspect of the present invention, in the method of induction hardening of a trunnion for a toroidal-type continuously variable transmission according to the first aspect, the temper temperature in the temper treatment is such that the hardness of the abutting portion is Hv550 after the temper treatment. The temperature is set to be as follows.
[0031]
In the invention described in claim 2, the toughness against quenching distortion is improved.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is characterized by the trunnion of the toroidal-type continuously variable transmission, and other configurations and operations are the same as those of the conventional configuration and operations described above. Therefore, only the features of the present invention will be described below. The other parts are denoted by the same reference numerals as those in FIGS. 7 to 11 and their detailed description is omitted.
[0035]
1 to 3 show a first embodiment of the present invention. In this embodiment, paying attention to the transfer surface portion S2 of the radial needle bearing 26 that is most securely required of the trunnion 6 is the contact portion (contact portion) with the tilt stopper 150. After induction hardening (high frequency HT) is performed on S1, the transfer surface portion S2 of the radial needle bearing 26 is induction hardened.
[0036]
Specifically, as shown in the flowchart of FIG. 3, first, induction hardening is performed on the contact portion S1 with the tilting stopper 150 (step S1), and then tempering is performed within 5 hours ( Step S2). In this case, the temper temperature is set to a temperature at which the hardness of the contact portion S1 becomes Hv550 or less after the temper process. In FIG. 1, a state where the induction hardening process is performed on the contact portion S <b> 1 with the tilt stopper 150 is indicated by hatching.
[0037]
When this tempering process is completed, the transfer surface portion S2 of the radial needle bearing 26 is subjected to an induction hardening process (step S3), and then the tempering process is performed within 5 hours (step S4). In FIG. 2, the state where the induction surface treatment is applied to the transfer surface portion S2 of the radial needle bearing 26 is indicated by hatching.
[0038]
Thus, in the present embodiment, the trunnion 6 is capable of tilting the pivot shaft 5 and the contact portion S1 that contacts the tilt stopper 150 for regulating the tilt amount of the trunnion 6 around the pivot shaft 5. And a transfer surface portion S2 of the radial needle bearing 26 that supports the shaft. After the induction hardening treatment is performed on the contact portion S1 with the tilting stopper 150, the temper treatment is performed, and then the radial needle bearing 26 The transfer surface portion S2 is subjected to induction hardening. Therefore, even if the quenching ranges are overlapped, the hardness of the transfer surface portion S2 of the radial needle bearing 26 can be ensured to a desired hardness.
[0039]
Moreover, when the induction hardening range overlaps, it hardens to a part with high hardness, and a toughness is insufficient in a part with high hardness with respect to the distortion at the time of re-quenching. As a result, burn cracks may occur. However, as in this embodiment, after quenching to the abutting portion S1 that abuts the tilt stopper 150, by performing tempering, it is possible to increase the toughness and stress release of the portion where high-frequency quenching overlaps. Less likely to occur.
[0040]
In the present embodiment, the temper temperature in the temper process of the contact portion S1 with the tilt stopper 150 is set to a temperature at which the hardness of the contact part S1 becomes Hv550 or less after the temper process. Therefore, the toughness against quenching distortion is improved.
[0041]
Further, in the present embodiment, the tempering process is performed within 5 hours after the induction hardening process is performed on the contact portion S1 with the tilt stopper 150. Accordingly, it is possible to prevent cracking after induction hardening.
[0042]
4 to 6 show a second embodiment of the present invention. In the present embodiment, the induction hardening treatment range for the abutting portion S1 of the trunnion 6 is limited to a predetermined range P so as not to overlap with the induction hardening treatment range for the transfer surface portion S2, as shown in FIG. ing. Also in this embodiment, after the induction hardening process is performed on the contact part S2, the transfer surface part S2 is subjected to the induction hardening process. Further, as shown in FIG. 6, the tilt stopper 150 has an escape portion 150 a in the central portion for escaping a portion other than the induction hardening range P of the trunnion 6 when the trunnion 6 is tilted. It only comes into contact with the induction hardening range P of the trunnion 6. FIG. 5 shows a cross-sectional view of the main part of a toroidal continuously variable transmission in which the trunnion 6 and the tilt stopper 150 having such a configuration are incorporated.
[0043]
【The invention's effect】
As described above, according to the invention described in claim 1, even if the quenching ranges are overlapped, the hardness of the transfer surface portion of the radial needle bearing can be ensured to a desired hardness, Moreover, generation | occurrence | production of a burning crack can be prevented.
[0044]
According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and the toughness against quenching distortion can be improved.
[Brief description of the drawings]
FIG. 1 shows a state where an induction hardening process is performed on a contact portion of a trunnion with a tilt stopper according to a first embodiment of the present invention, and (a) is a view of the trunnion viewed from its axial direction; (B) is the figure which looked at the trunnion of (a) from the side by which a power roller is supported.
FIG. 2 shows a state where the transfer surface portion of the radial needle bearing of the trunnion according to the first embodiment of the present invention has been subjected to induction hardening, (a) is a view of the trunnion viewed from its axial direction; (B) is the figure which looked at the trunnion of (a) from the side by which a power roller is supported.
FIG. 3 is a flowchart showing a procedure of induction hardening processing in the present invention.
FIGS. 4A and 4B show a state where induction hardening is applied to a trunnion according to a second embodiment of the present invention, wherein FIG. 4A is a view of the trunnion viewed from its axial direction, and FIG. The figure which looked at the trunnion of (a) from the side performed, (c) is sectional drawing which follows the CC line of (a), (d) is sectional drawing which follows the DD line of (a).
FIG. 5 is a cross-sectional view of a main part of a toroidal continuously variable transmission incorporating a trunnion according to a second embodiment of the present invention.
6A is a side view of the trunnion and the tilt stopper as viewed from the direction E in FIG. 5, and FIG. 6B is a plan view of the trunnion contact portion (high frequency quenching portion) by tilting the trunnion from the state of FIG. It is a side view which shows the state which contact | abutted only to the inclination stopper.
FIG. 7 is a side view showing a basic configuration of a conventionally known toroidal continuously variable transmission in a state of maximum deceleration.
FIG. 8 is a side view showing a basic configuration of a conventionally known toroidal type continuously variable transmission in a state of maximum speed increase.
FIG. 9 is a cross-sectional view showing an example of a conventional specific structure.
10 is a cross-sectional view taken along line AA in FIG.
FIG. 11 shows a state where a conventional trunnion is subjected to induction hardening, (a) is a view of the trunnion viewed from its axial direction, and (b) is a view of (a) from the side where the power roller is supported. The figure which looked at the trunnion, (c) is sectional drawing which follows the BB line of (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input shaft 2 Input side disk 2a Inner side surface 3 Output shaft 4 Output side disk 4a Inner side surface 5 Pivot 6 Trunnion 11 Power roller 11a Circumferential surface 26 Radial needle bearing 150 Tilt stopper 150a Escape part S1 Contact part (contact part)
S2 Transfer surface

Claims (2)

A toroidal type that supports the power roller sandwiched between the input and output discs in a freely rotating manner and tilts around a pivot that is twisted with respect to the central axis of the input and output discs. In the induction hardening method of applying induction hardening to the trunnion of the continuously variable transmission,
The trunnion has a contact portion that contacts a tilt stopper for restricting a trunnion tilt amount around the pivot, and a transfer surface portion of a radial needle bearing that pivotally supports the pivot. And
After induction hardening process is applied to the contact portion between the tilting stopper, tempering is performed, thereafter, the feature that the induction hardening process is facilities to the transfer surface of the radial needle bearing Induction hardening method for trunnion of toroidal type continuously variable transmission. The method for induction hardening of a trunnion for a toroidal continuously variable transmission according to claim 1, wherein the temper temperature in the temper process is set to a temperature at which the hardness of the contact portion becomes Hv550 or less after the temper process. .

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