JP2004132454A - Toroidal continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toroidal continuously variable transmission for preventing reduction in durability of a displacement shaft and a power roller. <P>SOLUTION: This toroidal continuously variable transmission has a trunnion 4 for arranging mutually concentric pivots 10 in both end parts, a pivot shaft 5 supported by this trunnion 4 and the power roller 20 for inserting this pivot shaft 5 into an inserting hole 20 and rotatably supported by the pivot shaft 5. An inserting hole 20b of the power roller 20 is formed so that an inner diameter of both end parts of this inserting hole 20b becomes larger than an inner diameter of an intermediate part of the inserting hole 20b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toroidal-type continuously variable transmission used for automobiles and the like.
[0002]
[Prior art]
As a conventional toroidal type continuously variable transmission, for example, a toroidal type continuously variable transmission shown in FIGS. 3 and 4 is known. In this toroidal type continuously variable transmission, the input side disk 3 is supported concentrically with the input shaft 1, and the output side disk 12 is fixed to an end of an output shaft 13 arranged concentrically with the input shaft 1. Inside the casing containing the toroidal-type continuously variable transmission, trunnions 4, 4 swinging about pivots 10, 10 which are twisted with respect to the input shaft 1 and the output shaft 13, are provided.
[0003]
As shown in FIG. 4, these trunnions 4 and 4 are provided at both ends in the longitudinal direction (left and right directions in FIG. 4) of the support plate portion 4b of the trunnion 4, on the inner surface side of the support plate portion 4b (FIG. (Upper side in FIG. 3). The pair of bent walls 4c, 4c formed in a state of being bent upward. The bent wall portions 4c, 4c form a concave pocket portion P for accommodating a power roller 7, which will be described later, in the trunnion 4. The pivots 10, 10 are provided concentrically on the outer surfaces (surfaces opposite to the support plate 4b) of the bent walls 4c, 4c.
[0004]
A support hole 4a is formed in the center of the support plate 4b, and pivot shafts (displacement axes) 5 and 5 are supported in the support hole 4a. By pivoting the trunnions 4 around the respective pivots 10, the angles of the pivot shafts 5 supported by the trunnions 4 can be adjusted.
Each pivot shaft 5, 5 has a support shaft 5a, a fitting shaft 5b, 5b and a pivot shaft 5c, 5c provided concentrically with each other. The axis L1 of the portion 5a and the axis L2 of the fitting shaft 5b and the pivot shaft 5c are parallel and eccentric to each other.
Each of the support shaft portions 5a, 5a is rotatably supported inside the support holes 4a, 4a of each trunnion 4, 4 via radial needle bearings 11, 11. Further, annular outer rings 6, 6 are externally fixed to the fitting shaft portions 5b, 5b. Further, the pivot shaft portions 5c, 5c are inserted into insertion holes 7b, 7b formed in the power rollers 7, 7, respectively.
[0005]
As shown in FIG. 3, each of the power rollers 7, 7 is rotatably supported on each of the pivot shafts 5c, 5c via a radial needle bearing 9, 9, and a peripheral surface of each of the power rollers 7, 7 is provided. 7 c, 7 c are sandwiched between the inner surface 3 a of the input disk 3 and the inner surface 12 a of the output disk 12.
[0006]
As shown in FIG. 4, a thrust ball bearing 8 and a thrust load applied to the outer ring 6 are arranged between the large end face 7 d of the power roller 7 and the inner surface of the trunnion 4 in order from the large end face 7 d of the power roller 7. And a thrust needle bearing 14 for supporting the same. The thrust ball bearing 8 is composed of a plurality of balls 8a, an annular retainer 8b that rotatably holds the balls 8a, and an outer ring 6. As shown in FIG. 5, an inner raceway 7a of a thrust bearing ball 8 forming an annular groove having a radius R is formed on a large end surface 7d of the power roller 7, and a radius R is formed on an inner surface of the outer race 6. The outer ring raceway 6a of the thrust ball bearing 8 forming an annular groove is formed.
[0007]
On the other hand, as shown in FIG. 3, a loading device 2 of a loading cam type is provided between the input shaft 1 and the input disk 3. The pressing device 2 elastically presses the input side disk 3 toward the output side disk 12. The pressing device 2 includes a cam plate 2a that rotates together with the input shaft 1, and a plurality of (for example, four) rollers 2c held by a holder 2b. A cam surface 2d, which is an uneven surface in the circumferential direction, is formed on one side surface (the left side surface in FIG. 13) of the cam plate 2a, and is formed on the outer side surface (the right side surface in FIG. 3) of the input side disk 3. Has a similar cam surface 3b. The plurality of rollers 2c are supported so as to be rotatable around an axis extending in a radial direction with respect to the input shaft 1.
[0008]
In the toroidal-type continuously variable transmission having such a configuration, when the input shaft 1 is rotated, the cam plate 2a rotates with the rotation, and the plurality of rollers 2c are moved by the cam surface 2d to form the input side disk 3. It is pressed by the cam surface 3b provided on the outer surface. As a result, the input side disk 3 is pressed by the power rollers 7 and 7 and at the same time, the input side disk 3 is pressed based on the pressing of the pair of cam surfaces 2d and 3b and the rolling surfaces of the plurality of rollers 2c. Rotates. Then, the rotation of the input side disk 3 is transmitted to the output side disk 12 via the respective power rollers 7, 7, and the output shaft 13 fixed to the output side disk 12 rotates.
[0009]
In the case where the rotation speed of the input shaft 1 and the output shaft 13 is changed, and when the speed is reduced between the input shaft 1 and the output shaft 13, the position is set to the upper side in FIG. The trunnion 4 is rotated clockwise by a predetermined angle in FIG. 3, and the trunnion 4 positioned on the lower side in FIG. 3 is rotated counterclockwise by a predetermined angle in FIG.
Conversely, when increasing the speed, the trunnion 4 located on the upper side in FIG. 3 is rotated by a predetermined angle counterclockwise in FIG. 3, and the trunnion 4 located on the lower side in FIG. Rotate a predetermined angle around.
[0010]
By the way, in the toroidal type continuously variable transmission having the above-described configuration, as shown in FIG. 4, the support hole 4a of the trunnion 4, the support shaft 5a of the pivot shaft 5, and the space between these support holes 4a and the support shaft 5a. A bearing gap (play) b is generated between at least any two of the radial needle bearings 11 provided in the above. A bearing is provided between at least two of the insertion hole 7b of the power roller 7, the pivot shaft portion 5c of the pivot shaft 5, and the radial needle bearing 9 provided between the insertion hole 7b and the pivot shaft portion 5c. A gap a is formed.
[0011]
When torque is transmitted in the order of the input disk 3, the power roller 7, and the output disk 12 in a state where the bearing gaps a and b are present, as shown in FIG. When the traction force T is applied, as shown in FIG. 6, the power roller 7 rotates in a state biased in the direction in which the traction force T is applied to the outer ring 6 (rightward in FIG. 4, hereinafter referred to as “traction direction”). Then, the pivot shaft 5 is in a state inclined in the traction direction.
As a result, the outer peripheral surface of the pivot shaft portion 5c of the pivot shaft 5 and the inner peripheral surface of the radial needle bearing 9 come into uneven contact (one contact), and the outer peripheral surface of the fitting shaft portion 5b of the pivot shaft 5 comes into contact with the power. In some cases, the inner peripheral surface of the insertion hole 7b of the roller 7 comes into contact with the roller 7 and the resistance of the contact portions C1, C2, and C3 increases. For this reason, a part of the outer peripheral surface of the pivot shaft 5, a part of the inner peripheral surface of the radial needle bearing 9, and a part of the inner peripheral surface of the insertion hole 7b of the power roller 7 are worn, so that the pivot shaft 5, the radial needle The bearing 9 and the power roller 7 are easily fatigued. Therefore, the durability of these members decreases.
[0012]
In order to avoid such a problem, as shown in FIG. 7, the outer peripheral surface of the pivot shaft 5c of the pivot shaft 5 is formed into a spherical convex surface, and both ends of the pivot shaft 5c are made thin. By doing so, when the pivot shaft 5 is inclined, there is a known configuration in which the pivot shaft 5 has a reduced contact with the pivot shaft 5c (see Patent Document 1).
[0013]
[Patent Document 1]
JP-A-11-72153
[Problems to be solved by the invention]
However, in the pivot shaft 5 as shown in FIG. 7, since the root portion of the pivot shaft 5c of the pivot shaft 5 is thin, the load due to the traction force T tends to concentrate on the root portion. In addition, the durability of the pivot shaft 5 decreases. Further, when the pivot shaft 5 is inclined, it is impossible to avoid a situation where the outer peripheral surface of the fitting shaft portion 5b of the pivot shaft 5 and the inner peripheral surface of the insertion hole 7b of the power roller 7 come into contact with each other. The contact lowers the durability of the pivot shaft 5 and the power roller 7.
[0015]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a toroidal-type continuously variable transmission that can prevent deterioration of the durability of a displacement shaft and a power roller.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, a toroidal-type continuously variable transmission according to claim 1 has a trunnion provided with concentric pivots at both ends, a displacement shaft supported by the trunnion, and a displacement shaft. In a toroidal-type continuously variable transmission including a power roller inserted into the insertion hole and rotatably supported on the displacement shaft, the insertion hole of the power roller has an inner diameter at both ends of the insertion hole. It is characterized in that it is formed to be larger than the inner diameter of the central axis of the insertion hole.
[0017]
According to the first aspect of the present invention, since the inside diameter of both ends of the insertion hole of the power roller is larger than the inside diameter of the middle portion of the insertion hole, the displacement shaft is inclined by the traction force applied to the power roller during driving. Also, since it is difficult for the outer peripheral surface of the displacement shaft to contact the both ends of the inner peripheral surface of the insertion hole of the power roller, wear of the displacement shaft and the power roller is reduced, and fatigue of the displacement shaft and the power roller is reduced. . Accordingly, the durability of the displacement shaft and the power roller is prevented from lowering, and the life of the displacement shaft and the power roller is extended.
Also, to avoid contact between the outer peripheral surface of the displacement shaft and the inner peripheral surface of the insertion hole of the power roller, it is not necessary to make a part of the displacement shaft thin, so the load due to traction force is concentrated on a part of the displacement shaft. do not do.
Further, since the displacement shaft and the inner peripheral surface of the insertion hole of the power roller hardly come into contact with each other, smooth power transmission is performed, and the efficiency of power transmission of the toroidal type continuously variable transmission is improved.
[0018]
In the toroidal type continuously variable transmission according to a second aspect, in the invention according to the first aspect, the insertion hole of the power roller has a cross-sectional shape of an inner peripheral surface protruding toward a center line of the insertion hole. It is characterized by being formed in an arc shape.
[0019]
According to the second aspect of the present invention, since the inner peripheral surface of the insertion hole of the power roller is formed in an arc shape having a sectional shape protruding toward the center line of the insertion hole, the insertion hole of the power roller is manufactured. Is easy.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the present invention lies in the point that the power roller is improved, and the other configurations and operations are the same as the above-described conventional configurations and operations. The other portions are denoted by the same reference numerals as those in FIGS. 3 to 7, and detailed description thereof will be omitted or simplified.
[0021]
1 and 2 show an embodiment of the present invention. As shown, the power roller 20 constituting the toroidal-type continuously variable transmission according to the present embodiment is inserted into an insertion hole 20b formed in the power roller 20, similarly to the case of the above-described conventional structure. The pivot shaft 5 is rotatably supported by a pivot shaft portion 5 c via a radial needle bearing (radial bearing) 9. An inner raceway 20a of the thrust bearing ball 8 forming an annular groove having a radius R is formed on the large end surface 20c of the power roller 20.
The insertion hole 20b of the power roller 20 is formed in a drum shape. That is, the insertion hole 20b is formed in an arc shape such that the cross-sectional shape of the inner peripheral surface 20d protrudes toward the center line of the insertion hole 20b, and gradually moves away from the center line toward both ends of the insertion hole 20b. Is formed. Thus, the inner diameter of the insertion hole 20b of the power roller 20 gradually increases toward both end surfaces of the power roller 20.
[0022]
In such a toroidal-type continuously variable transmission, since the inner diameter of the insertion hole 20b of the power roller 20 gradually increases toward both end surfaces of the power roller 20, the inner diameter of both ends of the insertion hole 20b is increased. Is larger than the inner diameter of the intermediate portion of the insertion hole 20b, so that even if the pivot shaft 5 is inclined in the traction direction by the traction force T applied to the power roller 20 during driving, the outer peripheral surface of the pivot shaft 5 and the power roller It is difficult for the two insertion holes 20b to come into contact with both ends of the inner peripheral surface 20d.
Therefore, wear of the pivot shaft 5 and the power roller 20 can be reduced, and fatigue of the pivot shaft 5 and the power roller 20 can be reduced. Accordingly, it is possible to prevent the durability of the pivot shaft 5 and the power roller 20 from being lowered, and to extend the life of the pivot shaft 5 and the power roller 20.
[0023]
Further, in order to avoid contact between the outer peripheral surface of the pivot shaft 5 and the inner peripheral surface 20d of the insertion hole 20b of the power roller 20, a part of the pivot shaft 5 does not need to be thinned. The concentration of the load due to the traction force can be prevented.
[0024]
Further, since the outer peripheral surface of the pivot shaft 5 and the inner peripheral surface 20d of the insertion hole 20b of the power roller 20 hardly come into contact with each other, smooth power transmission can be performed, and the power transmission efficiency of the toroidal type continuously variable transmission can be achieved. Can be improved.
[0025]
Further, since the cross-sectional shape of the inner peripheral surface 20d of the insertion hole 20b of the power roller 20 is formed in an arc shape, the insertion hole 20b of the power roller 20 can be easily manufactured.
[0026]
In the above-described embodiment, the insertion hole 20b of the power roller 20 is formed such that the cross-sectional shape of the inner peripheral surface 20d is an arc shape. Instead, the insertion hole 20b is inclined at the inner peripheral surface 20d. Only the two ends contacting the pivot shaft 5 are formed so as to have an arc-shaped cross section, or these two ends are inclined such that the inner diameter of the insertion hole 20b gradually increases toward the end face of the power roller 20. It may be formed on an inclined surface. The point is that the inside diameter of both ends of the insertion hole 20b of the power roller 20 should be larger than the inside diameter of the middle part of the insertion hole 20b.
【The invention's effect】
As described above, according to the present invention, it is possible to provide a toroidal-type continuously variable transmission that can prevent deterioration in the durability of the displacement shaft and the power roller.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a power roller and a trunnion of a toroidal-type continuously variable transmission according to an embodiment of the present invention.
FIG. 2 is a sectional view showing a power roller and an outer ring of FIG. 1;
FIG. 3 is a sectional view schematically showing a conventional toroidal-type continuously variable transmission.
FIG. 4 is a sectional view taken along line AA of FIG.
FIG. 5 is a sectional view showing the power roller and the outer ring of FIG. 3;
FIG. 6 is a cross-sectional view showing a state where traction force is applied when the toroidal type continuously variable transmission shown in FIG. 3 is operating.
FIG. 7 is a diagram illustrating an example of a pivot shaft of a conventional toroidal-type continuously variable transmission.
[Explanation of symbols]
4 trunnion 5 pivot shaft (displacement axis)
10 Axis 20 Power roller 20b Insertion hole 20d Inner peripheral surface

Claims (2)

A trunnion provided with concentric pivots at both ends, a displacement shaft supported by the trunnion, and a power roller inserted into the insertion hole and rotatably supported by the displacement shaft. The toroidal type continuously variable transmission,
A toroidal-type continuously variable transmission, wherein the insertion hole of the power roller is formed such that the inside diameter of both ends of the insertion hole is larger than the inside diameter of the center axis of the insertion hole. The toroidal-type continuously variable transmission according to claim 1, wherein the insertion hole of the power roller has an inner peripheral surface formed in an arc shape protruding toward a center line of the insertion hole. Machine.

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