JP3951387B2 - Ball spline of toroidal type continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ball spline that is provided at a joint portion between a torque input shaft and an input disk in a toroidal type continuously variable transmission used as a transmission of an automobile, for example, and drives and connects them.
[0002]
[Prior art]
A toroidal-type continuously variable transmission, which has been studied mainly as a transmission for automobiles, is sandwiched between an input disk and an output disk, each of which has an arcuate concave cross section on the surfaces facing each other. At least one set of toroidal transmission mechanisms having a structure in which a plurality of freely rotatable power rollers are combined. The input disk is mounted so as to be able to rotate integrally with the torque input shaft and to be restricted from moving in the direction of the torque input shaft, while the output disk is relatively fixed to the torque input shaft. It is mounted opposite to the input disk so that it can be rotated and movement in the direction away from the input disk is restricted.
[0003]
In the toroidal transmission mechanism as described above, when the input disk rotates, the output disk rotates in reverse via the power roller. Therefore, the rotational motion input to the torque input shaft is converted to the output disk as a reverse rotational motion. Transmitted and taken out. At this time, the speed of rotation from the torque input shaft to the output gear is increased by changing the inclination angle of the rotating shaft of the power roller so that the peripheral surface of the power roller is in contact with the vicinity of the outer periphery of the input disk and the center of the output disk. On the contrary, the torque input shaft is changed by changing the tilt angle of the rotation shaft of the power roller so that the peripheral surface of the power roller is in contact with the vicinity of the center of the input disk and the vicinity of the outer periphery of the output disk. To the output gear. Further, an intermediate gear ratio can be obtained almost steplessly by appropriately adjusting the inclination angle of the rotating shaft of the power roller.
[0004]
Also, a loading cam device that can increase or decrease the pressing force in the direction of the torque input shaft in accordance with the magnitude of the input torque is disposed between the input disk direction end of the torque input shaft and the input disk. The frictional force generated between the power roller and the power roller and between the power roller and the output disk is always adjusted to an appropriate magnitude. Further, the input disk is drivingly coupled to the torque input shaft in a state in which movement in the direction of the torque input shaft is allowed in order to operate the loading cam device effectively.
[0005]
Such drive coupling is achieved by, for example, providing a ball spline composed of a plurality of spline gaps and a plurality of balls arranged in series in the spline gaps on the joint surface between the input disk and the torque input shaft. It is realized by. The spline gap is constituted by a plurality of spline grooves formed to face each other along the torque input shaft direction on the inner wall surface of the mounting hole formed in the center of the input disk and the outer peripheral surface of the torque input shaft, A pair of opposing spline grooves functions as a spline gap for one row of balls. Each spline groove is a linear recess having a semicircular cross section, and is equally arranged in the circumferential direction in the torque input shaft cross section.
[0006]
[Problems to be solved by the invention]
When the input disk rotates in contact with the power roller, the input disk is partially deformed by the strong pressing force acting from the loading cam device, and the direction and rate of this deformation is along the circumferential direction of the power roller. It changes depending on the position. For example, the input disk expands in the outer direction at a portion in phase with the power roller (that is, the contact point of each power roller), while the inner diameter is at a portion corresponding to the intermediate phase between the contact points of two adjacent power rollers. Shrink in the direction.
[0007]
FIG. 3 shows an example of an input disk incorporated in a toroidal-type continuously variable transmission having two power rollers. In this figure, the input disk 1 is viewed from the contact surface side with the power roller, and a mounting hole 2 for penetrating the torque input shaft is formed at the center. Further, the input disk 1 abuts against each power roller at two abutment points 3 and 3 on the left side and the right side respectively indicated by a circled + symbol in the drawing. When a strong pressing force is applied to such an input disk 1 from the loading cam device, the load applied around the contact points 3 and 3 with the two power rollers partially increases. As shown by the above, the contour of the input disk 1 before being deformed, which was a perfect circle, is stretched leftward and rightward, and deformed into a horizontally long elliptical shape as indicated by a broken line.
[0008]
FIG. 4 shows an example of an input disk incorporated in a toroidal-type continuously variable transmission similarly having three power rollers, and the upper and right sides respectively indicated by a circled + symbol in the figure. The input disk 1 comes into contact with each power roller at three contact points 3, 3, and 3 on the lower side and the lower left side. When a strong pressing force is applied to such an input disk 1 from the loading cam device, the load applied around the contact points 3, 3 and 3 with the three power rollers partially increases. As shown by the solid line in the figure, the contour of the input disk 1 before being deformed, which was a perfect circle, is stretched in the upward direction, the lower right direction, and the lower left direction, resulting in the shape indicated by the broken line. And transformed.
[0009]
When the deformation of the input disk 1 occurs in this way, the gap between the outer peripheral surface of the torque input shaft and the inner wall surface of the mounting hole 2 of the input disk 1 partially increases or decreases. Therefore, when the ball spline provided on the joint surface between the torque input shaft and the input disk 1 overlaps with the deformation region of the input disk 1 by the loading cam device, the spline gap formed by a plurality of spline grooves is formed. Something will deviate from the normal interval. For example, at the portion where the input disk 1 swells in the same phase as the power roller (that is, the contact point of each power roller), the spacing between the spline gaps is larger than the appropriate value, and the contact point between two adjacent power rollers. In the portion where the input disk 1 contracts in the intermediate phase, the interval between the spline gaps is reduced from an appropriate value.
[0010]
As a result of the shrinkage of the input disk 1, if the spline gap becomes smaller than the diameter of the balls arranged in series in the spline gap, the load applied to each ball in the spline gap increases and the surface pressure becomes excessive. become. As a result, the increase in the rotational load of the ball prevents the ball spline from moving in the direction of the torque input shaft, which not only lowers the transmission efficiency of the entire toroidal type continuously variable transmission, but also causes indentation and climbing. Ball splines are easily damaged. In particular, when the number N of the spline gaps of the ball spline is an integral multiple of the number Np of the power rollers, the spline gap having the same number as the number Np of the power rollers, which is the greatest common divisor of N and Np. Since the input disk 1 is simultaneously positioned at the maximum contracted portion of the input disk 1 (that is, the intermediate phase portion between the contact points of the two power rollers), the tendency of the above-described decrease in transmission efficiency and increase in the breakage rate becomes stronger.
[0011]
For example, in FIG. 5 showing an example in which six spline grooves 4 are formed in the input disk 1 in contact with the two power rollers shown in FIG. 3, the shape shown by the solid line in the figure is indicated by a dotted line. Due to the deformation of the input disk 1 into the shape shown, the inner diameter of the mounting hole 2 is greatly reduced for the two strips 4a and 4a located on the upper side and the lower side of the six equally arranged spline grooves 4. Yes. As a result, the interval between the spline gaps formed by the upper and lower spline grooves 4a and 4a is narrowed, and the load applied to the ball rows arranged in these spline grooves is increased. Further, in FIG. 6 showing an example in which six spline grooves 4 are provided in the input disk 1 in contact with the three power rollers shown in FIG. 4, 6 etc. according to the deformation of the input disk. Among the arranged spline grooves, the inner diameters of the mounting holes 2 around the three spline grooves 4b, 4b, and 4b located on the upper left side, the upper right side, and the lower side are greatly reduced. As a result, the space between the spline gaps formed by the upper left, upper right, and lower spline grooves 4b, 4b, and 4b is narrowed, and the load applied to the ball row disposed in these spline grooves is increased. .
[0012]
The present invention has been made in accordance with the above-described circumstances, and when the input disk is deformed by the pressing force from the power roller, the number of spline gaps that applies the maximum load to the ball row is reduced as much as possible. Thus, it is an object of the present invention to provide a ball spline for a toroidal type continuously variable transmission that can reduce ball spline trouble and transmission loss caused by excessive surface pressure.
[0013]
[Means for Solving the Problems]
The present invention provides a plurality of spline grooves formed to face each other along the direction of the torque input shaft on the outer peripheral surface of the torque input shaft and the inner wall surface of the mounting hole provided in the center of the input disk, and A plurality of balls arranged in series in the spline gap formed by the spline groove, and allowing the input disk to move in the direction of the torque input shaft by contacting the spline gap and the ball. The present invention relates to a ball spline of a toroidal-type continuously variable transmission for drivingly coupling the torque input shaft and the input disk, and the object of the present invention is to transmit rotational torque between the input disk and the output disk. a power roller is sandwiched on both disks in both disk and state abutting on the spline clearance between the number of the power rollers Greatest common divisor number of conditions is effectively achieved by was set to 1.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the ball spline of the present invention, the number of splines is set so that the number N of spline gaps does not become an integral multiple of the number Np of power rollers in contact with the input disk. As a result, even when a pressing force is applied from the power roller to cause partial deformation of the input disk, the phase of the deformation area of the input disk and the position where the spline grooves are formed always have the greatest promise of N and Np. Since the overlapping occurs only at the same number of points as the number, the number of spline gaps whose intervals are greatly reduced from the appropriate value is at least half of Np. In this way, the number of ball rows to which the maximum load is applied is greatly reduced as compared with the conventional ball spline, so that it is possible to minimize trouble and transmission loss of the ball spline caused by excessive surface pressure. Further, since the load applied to each spline groove is equalized due to the reduction in the number of ball rows to which the maximum load is applied, the upper limit of the load resistance of the ball spline can be set lower than in the prior art.
[0015]
In particular, when both are selected such that the number N of spline gaps and the number Np of power rollers in contact with the input disk are relatively prime, the greatest common divisor of N and Np is always 1, The point where the phase of the deformation area of the input disk overlaps with the position where the spline groove is formed is always one point. Therefore, the number of ball rows to which the maximum load is applied is also one row. For this reason, ball spline troubles and transmission loss caused by excessive surface pressure are drastically reduced as compared with conventional ball splines.
[0016]
FIG. 1 shows an embodiment of an input disk in which spline gaps forming spline gaps are formed in a ball spline of a toroidal-type continuously variable transmission according to the present invention. It is configured in the same manner as an input disk having a conventional spline groove. Similarly to FIG. 3, the two power rollers abut on the left and right abutment points 3 and 3 as well as the input disk 1 in this figure. Moreover, the spline groove | channel 4 currently formed in the mounting hole 2 inner wall surface of the input disk 1 so that it may become equal arrangement | positioning is three. For this reason, even when the input disk is deformed from a solid circular shape to a horizontally long elliptical shape as shown by a broken line by the pressing force from the power roller, it overlaps with the phase at which the inner diameter of the mounting hole 2 is greatly reduced. The spline gap is only constituted by one spline groove 4a on the upper side.
[0017]
FIG. 2 shows another embodiment of the input disk in which spline gaps forming the spline gap are formed in the ball spline of the toroidal-type continuously variable transmission according to the present invention. The power roller is in contact with each contact point 3 on the upper side, lower left side, and lower right side. Further, four spline grooves 4 are provided on the inner wall surface of the mounting hole 2 of the input disk 1 so as to be equally arranged. Also in this example, the phase in which the inner diameter of the mounting hole 2 is greatly reduced when the input disk is deformed from a solid circular shape to a horizontally long elliptical shape such as a broken line by the pressing force from the power roller. The spline gap that overlaps is only that formed by the single spline groove 4b on the lower side.
[0018]
In addition, although the example of the combination of two power rollers and three spline grooves and the example of the combination of three power rollers and four spline grooves have been described here, the present invention is not necessarily a combination of these numbers. It is not limited to. For example, the ball spline of the toroidal type continuously variable transmission of the present invention can also be configured by combining five spline grooves with two, three, or four power rollers.
[0019]
【The invention's effect】
As described above, according to the ball spline of the toroidal type continuously variable transmission according to the present invention, even when the input disk is deformed by the pressing force from the power roller, the spline that applies the maximum load to the ball row. The number of gaps is smaller than in the prior art, and the transmission efficiency of the entire toroidal continuously variable transmission can be maintained high. Further, since the indentation and the ride-up are less likely to occur, the damage rate of the ball spline can be reduced.
[0020]
Further, in the ball spline of the toroidal type continuously variable transmission according to the present invention, the load applied to each spline groove is equalized, so the number of spline gaps can be reduced and the number of balls arranged in one spline gap. Can be reduced. For this reason, it becomes possible to reduce the size and weight of the entire toroidal type continuously variable transmission, and it is also effective in reducing costs during production and maintenance.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of an input disk in which spline grooves forming a spline gap are formed in a ball spline of a toroidal-type continuously variable transmission according to the present invention.
FIG. 2 is a front view showing another embodiment of the input disk in which spline grooves forming spline gaps are formed in the ball spline of the toroidal type continuously variable transmission of the present invention.
FIG. 3 is a front view showing an example in which an input disk incorporated in a toroidal-type continuously variable transmission including two power rollers is deformed.
FIG. 4 is a front view showing an example in which an input disk incorporated in a toroidal-type continuously variable transmission including three power rollers is deformed.
5 is a front view showing an example in which six spline grooves are formed on the input disk with which the two power rollers shown in FIG. 3 abut. FIG.
6 is a front view showing an example in which six spline grooves are provided on the input disk with which the three power rollers shown in FIG. 4 abut. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input disk 2 Mounting hole 3 Power roller contact point 4 Spline groove 4a, 4b Spline groove which overlaps with the phase where an internal diameter is greatly reduced

Claims (1)

A plurality of spline grooves formed to oppose each other along the direction of the torque input shaft on the outer peripheral surface of the torque input shaft and the inner wall surface of the mounting hole provided in the center of the input disk, and the respective sets of spline grooves facing each other. And a plurality of balls arranged in series in the spline clearance, and the torque input shaft while allowing the input disk to move in the direction of the torque input shaft by contact between the spline clearance and the ball. In the ball spline of the toroidal type continuously variable transmission for drivingly connecting the input disk and the input disk,
In order to transmit rotational torque between the input disk and the output disk, a power roller is provided that is sandwiched between the two disks in a state in contact with both disks .
A ball spline for a toroidal-type continuously variable transmission , wherein the greatest common divisor of the number of power rollers and the number of strips of the spline gap is 1 .

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