JP4296808B2 - Toroidal continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toroidal continuously variable transmission used as a transmission for an automobile, for example.
[0002]
[Prior art]
For example, in a toroidal type continuously variable transmission used as a transmission for an automobile, a trunnion drive device is known in which a cable groove is provided in the trunnion and a safety cable is passed over in order to synchronize the tilt angle of the trunnion (for example, (See Patent Document 1).
[0003]
Patent Document 1 is configured as shown in FIGS. That is, an input disk 2 and an output disk 3 are rotatably supported via a needle bearing on an input shaft 1 connected to a drive source (not shown) such as an engine. A cam plate 4 is splined to the input shaft 1 on the back side of the input disk 2, and a roller 5 is interposed between the cam plate 4 and the input disk 2, and the input disk 2 is connected to the output disk 3. A pressing mechanism 6 of a loading cam type or a hydraulic loading type that is pressed to the side is provided.
[0004]
Between the input disk 2 and the output disk 3, trunnions 8a and 8b swinging around the tilt shaft 7 are provided, and a displacement shaft 9 is provided at the center of the trunnions 8a and 8b. A power roller 10 is rotatably supported on the displacement shaft 9, and the power roller 10 has a traction portion in contact with the input disk 2 and the output disk 3, and is tilted between the input disk 2 and the output disk 3. Rolling contact is possible.
[0005]
A power roller bearing 11 is provided between the trunnions 8 a and 8 b and the power roller 10. The power roller bearing 11 supports the rotation of the power roller 10 while supporting a load in the thrust direction applied to the power roller 10. A plurality of balls 12 of such a power roller bearing 11 are provided by an annular retainer 14 provided between an annular outer ring 13 provided on the trunnions 8a and 8b and a power roller 10 as a rotating portion. Is retained.
[0006]
Further, a cable groove 15 is provided in the outer peripheral portion of the end of the tilt shaft of the trunnions 8a and 8b. A wire rope 16 is connected to the cable groove 15 by an arcuate tube 17 in an endless loop shape. The safety cable 18 that has been used is stretched over. The safety cable 18 serves to synchronize the tilting (swinging about the tilting shaft 7) of the trunnions 8a and 8b with each other.
[0007]
By the way, the toroidal-type continuously variable transmission configured as described above requires both the disks 2 and 2 to transmit power from the input disk 2 to the power roller 10 and from the power roller 10 to the output disk 3 by the shearing force of oil. It is necessary to apply stress equivalent to gigapascal to the contact portion between the power roller 3 and the power roller 10.
[0008]
As a method of applying this stress, as described above, the loading cam type or hydraulic loading type pressing mechanism 6 is provided. As shown in FIG. 6, the axial force P is generated to generate the pressing stress Fc between the disks 2 and 3 and the power roller 10.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-294549
[Problems to be solved by the invention]
However, in the half-toroidal continuously variable transmission, a load is generated in the direction of the rotational axis of the power roller 10 due to its geometric shape, and this becomes the thrust load Fs generated in the trunnions 8a and 8b. The thrust load Fs is structured to be supported by both ends of the trunnions 8a and 8b and the yoke 19, and as shown in FIG. 7, the trunnions 8a and 8b are bent and deformed so that the cross-sectional shapes of the trunnions 8a and 8b are continuous. A large amount of stress is generated in an unsuitable part.
[0011]
Incidentally, as shown in FIG. 5, a cable groove 15 for attaching the safety cable 18 is provided on the outer peripheral portion of the tilt shaft end portion of the conventional trunnions 8a and 8b. It has occurred. In the toroidal type continuously variable transmission that transmits torque in a high region, the axial force P needs to be increased, so that the load applied to the trunnions 8a and 8b increases, and the cable groove 15 of the safety cable 18 of the trunnions 8a and 8b is large. Stress is generated.
[0012]
The present invention has been made paying attention to the above circumstances, and the object of the present invention is to reduce the stress of the trunnion locally even if a large axial force is applied from a loading cam type or hydraulic loading type pressing mechanism. To provide a toroidal type continuously variable transmission capable of improving the performance.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an input shaft and an input disk and an output disk that are rotatably supported by the input shaft concentrically with each other, with each other concentrically and independently of each other. And at least a pair of trunnions having a tilt axis at a position perpendicular to the direction of the center axis of the input disk and the output disk, and tilting about the tilt axis, and the trunnion is freely rotatable. A plurality of power rollers that are supported between the traction surfaces of the input disk and the output disk, and a safety cable that spans the trunnions and synchronizes the tilt angles of at least a pair of trunnions. In the toroidal continuously variable transmission provided with the safety cable, only the circumferential ends of the outer peripheral surface of the end portion of the trunnion are provided with the safety casing. Provided cable groove for mounting the table, an intermediate portion other than the both end portions of the cable groove is not circumferential direction of said trunnion has an axial cross section continuously changing the flat surface of the back of the trunnion, the said intermediate portion The angle formed by the flat surface is greater than 90 °.
[0015]
According to the above configuration, the cable groove for attaching the safety cable is provided only at both ends of the outer peripheral portion of the tilt shaft end portion of the trunnion, so that the intermediate portion other than the both ends of the trunnion without the cable groove is continuous with the rear surface of the trunnion. Since the shape changes with time, the stress in this vicinity is reduced. Therefore, even if a large axial force is applied from the loading cam type or hydraulic loading type pressing mechanism, the stress of the trunnion is reduced and the durability can be improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
1 and 2 show a first embodiment. FIG. 1 is a perspective view of a trunnion, and FIG. 2 is a longitudinal front view of the trunnion and power roller.
[0018]
The trunnion 21 of the present embodiment is provided with a pair of concentric tilting shafts 22 at both ends, and a flat surface 23 is formed on the back surface of the intermediate portion. A part of the flat surface 23 is provided with a circular hole 24 that supports the displacement shaft 9 of the power roller 10. Further, a pair of bent portions 25 are provided at both ends of the trunnion 21 to provide the tilt shaft 22, and a bag portion 26 surrounding the power roller 10 is formed.
[0019]
Below the flat surface 23 on the back surface of the trunnion 21, the connecting portion with the tilt shaft 22 on the lower side has an arc shape in cross section, and there is a safety cable at both ends, that is, at the boundary with the bag portion 26. A cable groove 27 for attaching 18 is provided. Further, an axial cross-section cross sectional shape other than both ends of the cable groove 27 has no trunnions 21 are arc-shaped intermediate portion 28 changes the flat surface 23 is continuously in back of the trunnion 21, an intermediate portion 28 The angle θ formed by the flat surface is larger than 90 °. That is, the conventional trunnion is provided with a cable groove for attaching the safety cable 18 below the flat surface on the back surface, but the trunnion 21 of the present invention has a lower surface than the flat surface 23 on the back surface. Cable grooves 27 are provided only at both ends.
[0020]
As described above, since the intermediate portion 28 having a circular cross section other than both ends of the trunnion 21 without the cable groove 27 has a shape that continuously changes with the back surface of the trunnion 21, the stress in the vicinity thereof is reduced. Therefore, even if a large axial force is applied from the loading cam type or hydraulic loading type pressing mechanism 6, the local stress of the trunnion 21 is reduced, and the durability can be improved.
[0021]
Further, by providing the cable groove 27 only at both ends on the outer peripheral surface of the tilt shaft end portion of the trunnion 21, the shape of the cable groove 27 is simplified, and the machining amount is reduced, thereby extending the tool life and machining time. Can be shortened, and the cost can be reduced. Furthermore, since the cross-sectional shape of the back surface of the trunnion 21 is continuous, a uniform structure is obtained during the heat treatment, and the trunnion 21 having a stable strength is obtained.
[0022]
Further, since the weight of the intermediate portion of the trunnion 21 without the groove shape is reduced, the weight of the entire transmission can be reduced as compared with the prior art, and an improvement in fuel consumption can be expected. In addition, material costs are reduced. Further, when the cross section of the rear surface of the trunnion 21 is continuously changed, the width direction is not more convex than the conventional one, and there are various effects that the transmission width direction can be made compact.
[0023]
【The invention's effect】
As described above, according to the present invention, the cable groove for attaching the safety cable is provided only at both ends of the outer peripheral surface of the tilt shaft end portion of the trunnion, so that the intermediate portion other than the both ends of the trunnion without the cable groove is provided. Since the shape changes continuously with the back of the trunnion, the stress in the vicinity is reduced. Therefore, even if a large axial force is applied from the loading cam type or hydraulic loading type pressing mechanism, it is possible to provide a toroidal continuously variable transmission that can reduce the stress on the trunnion locally and transmit a larger torque. Can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view of a trunnion according to a first embodiment of the present invention.
FIG. 2 is a longitudinal side view of a trunnion and a power roller in the same embodiment.
FIG. 3 is a longitudinal side view showing a conventional toroidal-type continuously variable transmission.
4 is a cross-sectional view taken along line XX in FIG.
FIG. 5 is a longitudinal side view of a trunnion and a power roller of a conventional toroidal-type continuously variable transmission.
FIG. 6 is an operation explanatory diagram of a conventional toroidal continuously variable transmission.
FIG. 7 is a longitudinal side view of a conventional toroidal-type continuously variable transmission in which a trunnion is deformed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Input shaft, 2 ... Input disc, 3 ... Output disc, 7 ... Tilt axis, 10 ... Power roller, 21 ... Trunnion, 18 ... Safety cable, 27 ... Cable groove

Claims (1)

An input shaft, an input disc and an output disc supported concentrically with each other, concentrically with each other, and independently of each other, and rotatable at right angles to the direction of the central axis of the input disc and the output disc A tilting shaft at a position, and at least a pair of trunnions tilting about the tilting shaft, and supported between the trunnions so as to be rotatable and between the traction surfaces of the input disk and the output disk. In a toroidal continuously variable transmission comprising a plurality of power rollers sandwiched between and a safety cable that spans the trunnion and synchronizes the tilt angles of at least a pair of trunnions,
A cable groove for attaching the safety cable is provided only at both ends in the circumferential direction on the outer peripheral surface of the end portion of the trunnion,
The intermediate part other than both ends in the circumferential direction without the cable groove of the trunnion is
An axial cross section continuously changing the flat surface of the back of the trunnion,
A toroidal continuously variable transmission characterized in that an angle formed by the intermediate portion and the flat surface is larger than 90 °.

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