JP3731267B2 - Toroidal continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a disk support structure of a toroidal-type continuously variable transmission employed in a vehicle or the like.
[0002]
[Prior art]
As a toroidal-type continuously variable transmission used for a vehicle or the like, one disclosed in JP-A-2-261950 is known.
[0003]
As shown in FIG. 5, this is provided with first and second toroidal speed change portions 82 and 84 composed of two sets of input / output disks arranged on the same axis, and a double-cavity type non-cavity design in which transmission torque is increased. A step transmission 1 is conventionally known.
[0004]
In FIG. 5, the continuously variable transmission 1 is connected to an engine via a torque converter T / C and a forward / reverse switching device 96, while an output shaft 94 is connected to a drive shaft.
[0005]
The first toroidal transmission unit 82 constituting the continuously variable transmission 1 has a pair of power rollers 82c and 82d sandwiched between opposing surfaces of the input disk 82a and the output disk 82b. Similarly, the second toroidal transmission unit 84 includes: A pair of power rollers 84c and 84d are sandwiched between opposing surfaces of the input disk 84a and the output disk 84b.
[0006]
The input disk 82a of the first toroidal transmission unit 82 and the input disk 84a of the second toroidal transmission unit 84 are coupled in the rotational direction via the torque transmission shaft 70, and the output disk 82b of the first toroidal transmission unit 82 and the The output disk 84 b of the two toroidal transmission unit 84 is coupled to the back surfaces thereof via the output gear 90 and is supported coaxially and rotatably relative to the torque transmission shaft 70 via the output gear 90.
[0007]
Further, the power rollers 82c and 82d of the first toroidal transmission unit 82 and the power rollers 84c and 84d of the second toroidal transmission unit 84 are driven synchronously by a shift control means (not shown), and the input / output disk is moved by a tilting motion. The gear ratio can be changed continuously by changing the contact radius.
[0008]
The driving force is transmitted and received by oil film shear stress between the input / output disk and the power roller. Therefore, the input disks 82a and 84a are axially connected to the torque transmission shaft 70 via the ball splines 86 and 88. A loading cam device 10 (biasing means) for generating axial thrust is disposed on the back surface of the input disk 82a of the first toroidal transmission unit 82, while the second toroidal transmission is supported. A disc spring 98 for providing a preload is disposed on the back surface of the input disk 84a of the section 84.
[0009]
Here, the support structure of the input disk 82a on the first toroidal transmission 82 side will be described. The loading cam device 10 disposed on the back surface of the input disk 82a is connected to the output side of the forward / reverse switching device 96. 97 is coaxially connected to the torque transmission shaft 70 via a thrust bearing 72, and a cam roller 44 is interposed between the drive plate 97 and the input disk 82a.
[0010]
Due to the relative rotation of the drive plate 97 and the input disk 82a, the cam roller 44 presses the input disk 82a toward the output disk 82b (the right side in FIG. 6), and as a result, the second toroidal speed change coupled via the torque transmission shaft 70. The input disk 84a of the section 84 is also pressed toward the output disk 84b, and the power rollers 82c, 82d and 84c, 84d sandwiched between the input / output disks 82a, 82b and 84a, 84b are pressed to transmit torque. It can be carried out,
Thus, in order to generate and transmit axial thrust, the ball splines 86 and 88 are interposed between the input disks 82a and 84a and the torque transmission shaft 70 and coupled in the rotational direction, while in the axial direction. The relative displacement of is allowed.
[0011]
As shown in FIG. 6, the ball spline 86 includes an axial groove portion 86a formed on the inner periphery of the input disk 82a, a groove portion 86b ′ formed on the outer periphery of the torque transmission shaft 70, and the groove portions 86a and 86b ′. It consists of a plurality of balls 86a interposed therebetween.
[0012]
The groove portions 86a and 86b ′ are formed in parallel to the axial direction of the torque transmission shaft 70, and the depth and width of these groove portions are set to constant values. Therefore, the input disks 82a and 84a are coupled in the rotational direction, and can be relatively displaced in the axial direction. Further, the input rollers 82a and 84a are prevented from being inclined with respect to the shaft, and the power rollers are accurately sandwiched and pressed between the output disks 82b and 84b. can do. A ball spline 88 interposed between the input disk 84a of the second toroidal transmission unit 84 and the torque transmission shaft 70 is also configured in the same manner, although not shown.
[0013]
[Problems to be solved by the invention]
However, in the conventional toroidal-type continuously variable transmission, the positions of the power rollers 82c, 82d and 84c, 84d may deviate from a predetermined position due to dimensional tolerances. 82a and 84a are coupled to a torque transmission shaft 70 as an input shaft through ball splines 86 and 88 around the shaft, while being supported so as to be relatively displaceable in the axial direction and inclined with respect to the input shaft. When the position of the power roller is shifted as described above, the input disks 82a and 84a are inclined due to the gaps between the input disks 82a and 84a and the torque transmission shaft 70 and elastic deformation of each part. Thus, the displacement of the position of the power roller was absorbed.
[0014]
When the input disks 82a and 84a are inclined due to such elastic deformation, a force is generated to return to the opposite side of the inclination direction, and the pressing force of the pair of power rollers becomes uneven. There is a problem that the torque transmission capacity of the machine 1 is reduced to a smaller pressing force.
[0015]
Accordingly, the present invention has been made in view of the above problems, and provides a toroidal continuously variable transmission that can prevent a decrease in torque transmission capacity regardless of positional deviation caused by dimensional tolerance of a power roller. Objective.
[0016]
[Means for Solving the Problems]
A first invention includes an input disk coupled to an input shaft, an output disk coupled to an output shaft, and a plurality of power rollers sandwiched between toroidal grooves formed on opposing surfaces of these input / output disks. And an urging means that presses the power roller via the input / output disk, and is interposed between the input shaft and the input disk so as to couple the input shaft and the input disk in the rotational direction. In the toroidal-type continuously variable transmission having a supporting means for allowing axial displacement, the supporting means is formed on one of the input shaft and the input disk and is parallel to the axis of the input shaft, and the input Formed on the other side of the shaft or the input disk, the groove width in the axial center portion facing the first groove portion is narrowed, the depth of the central portion in the axial direction is also made shallow, and the groove width and width toward both ends are increased. A second groove depth increases, is composed of a plurality of balls interposed between the first and second grooves, to allow tilting of the input disk to the input shaft.
[0018]
【The invention's effect】
Therefore, in the first invention, when the position of the power roller held and pressed between the input disk and the output disk deviates from a predetermined position due to a dimensional tolerance or the like, the input disk is inclined with respect to the input shaft. The pair of power rollers can be contacted equally. At this time, since there is no elastic deformation as in the prior art, no reaction force against the inclination is generated, and the pressing force against the pair of power rollers is uniformly maintained. Therefore, it is possible to prevent a decrease in torque transmission capacity of the continuously variable transmission while absorbing a positional deviation due to dimensional tolerance, and it is possible to improve the performance of the toroidal continuously variable transmission.
[0019]
Then, the support means for the input disk is formed with one of the input shaft and the input disk having a second groove part in which the groove width and depth increase from the center of the axial length toward both ends. Since the first groove portion that is parallel to the shaft is formed and the ball is inserted between the first and second groove portions, the input disk is inclined with respect to the center of the entire length of the groove portion as a pair. Even if the power roller is displaced due to dimensional tolerance, etc., it can be contacted equally. At this time, since there is no elastic deformation as in the conventional example, no reaction force against the inclination is generated, and a pair of power rollers It is possible to keep the pressing force against the rollers even.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0021]
FIGS. 1 to 3 show an example in which the present invention is applied to the double cavity type toroidal continuously variable transmission 1 shown in FIG. 5 of the conventional example. Only the ball spline 86 interposed between the input disk 82a of the toroidal transmission 82 and the torque transmission shaft 70 is shown, and the groove 86b 'in the conventional example is changed to the groove 86b. The configuration is the same as in FIG. 5 of the example, and the same components are denoted by the same reference numerals, and redundant description is omitted.
[0022]
Between the input disk 82a and the torque transmission shaft 70 as an input shaft, a ball spline 86 that is coupled in the rotational direction and is allowed to be relatively displaced in the axial direction is interposed.
[0023]
The ball spline 86 includes a groove portion 86c (first groove portion) formed on the inner periphery of the input disk 82a, a groove portion 86b (second groove portion) formed on the outer periphery of the torque transmission shaft 70, both groove portions 86c, It is composed of a plurality of balls 86a engaged with 86b.
[0024]
The groove 86c formed on the inner periphery of the input disk 82a is formed in parallel with the axis of the torque transmission shaft 70 as in the conventional example, and the depth and width of the groove 86c are set to constant values. .
[0025]
On the other hand, the groove portion 86b formed on the outer periphery of the torque transmission shaft 70 is formed as a concave portion having a predetermined length L in a range facing the groove portion 86c on the input disk 82a side, and the groove width W and the depth D are the total length L. This is variable from the center to the both ends 86e.
[0026]
First, in the cross section along the center line C in the width direction, the depth D of the groove 86b is the shallowest Dc at the center of the full length L as shown in FIGS. 1 and 3, and both ends 86e from this center. A curve R is formed such that the depth gradually increases toward the end, and the maximum depth De is obtained at a predetermined position between the end portion and the center portion. The depth decreases from the position of the depth De toward the end portion 86e, and the depth D = 0 at both end portions 86e. The depth Dc at the center is set to a minimum value at which the ball 86a can roll, and the maximum depth De can tilt the input disk 82a by a predetermined amount in the ZY plane in the figure. Set to the correct value.
[0027]
As shown in FIGS. 2 and 3, the groove width W is the narrowest Wc at the center of the full length L, and has a curve R2 that gradually increases from the center toward both ends 86e. The maximum width We is obtained at a predetermined position between the end portion 96e and the central portion.
[0028]
The width W gradually decreases from the position of the maximum width We toward the end portion 86e, and the width W = 0 at both end portions 86e. The central width Wc is set to a minimum value at which the ball 86a can roll, and the maximum width We is a value at which the input disk 82a can be inclined by a predetermined amount in the XY plane in the drawing. Set to
[0029]
Although not shown, the ball spline 88 between the input disk 84a of the second toroidal transmission 84 and the torque transmission shaft 70 is also formed in the same manner as described above, and the input disk 84a is inclined with respect to the torque transmission shaft 70. It becomes possible.
[0030]
Next, the operation will be described.
[0031]
The groove 86b on the side of the torque transmission shaft 70 constituting the ball spline 86 is formed such that the center portion thereof is raised by a curve R at the bottom, and the groove width W has a groove width W from the center portion to the end portion 86e. Since it is formed with a curve R2 that expands toward the end, a gap is formed between the ball 86a on the end 86e side and the groove 86b, and the input disk 82a has an XY axis about the center of the entire length L of the groove 86e. Inclination is possible in the plane and the ZY plane.
[0032]
Therefore, when the positions of the power rollers 82c and 82d sandwiched and pressed between the input disk 82a and the output disk 82b deviate from a predetermined position due to dimensional tolerances, the input disk 82a is centered on the entire length L of the groove 86b. As shown in FIG. 4, the shaft can be in contact with the pair of power rollers 82 c and 82 d equally at the XY plane and the ZY plane. Therefore, the reaction force against the inclination is not generated, and the pressing force of the pair of power rollers 82c and 82d can be kept even, and the continuously variable transmission can absorb the positional deviation due to the dimensional tolerance. 1 can be prevented, and the performance of the toroidal-type continuously variable transmission can be improved.
[0033]
When machining the groove 86b, a cutter or the like corresponding to the cross-sectional shape of the groove 86b is cut in a direction perpendicular to the axis so that the central portion becomes shallower in accordance with the feed in the axial direction. Can be easily processed.
[0034]
In the above embodiment, the groove 86b is formed on the torque transmission shaft 70 and the groove 86c is formed on the input disk 82a. Conversely, the groove 86c may be formed on the torque transmission shaft 70 and the groove 86b may be formed on the input disk 82a. Good.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an input disk support structure according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is an explanatory diagram showing the operation, and is a conceptual diagram of a first toroidal transmission unit.
FIG. 5 is a schematic configuration diagram of a toroidal-type continuously variable transmission showing a conventional example. FIG. 6 is a cross-sectional view of an essential part showing a support structure for an input disk.
[Explanation of symbols]
1 continuously variable transmission 10 loading cam device 44 cam roller 70 torque transmission shaft 82 first toroidal transmission 82a input disk 82b output disk 82c, 82d power roller 84 second toroidal transmission 84a input disk 84b output disks 84c, 84d power roller 86 , 88 Ball spline 86a, 88a Ball 86b, 86c Groove 97 Drive plate

Claims (1)

An input disk connected to the input shaft;
An output disk coupled to the output shaft;
A plurality of power rollers sandwiched between toroidal grooves formed on the opposing surfaces of these input / output discs;
Biasing means for pressing the power roller through the input / output disk;
In a toroidal continuously variable transmission that is interposed between the input shaft and the input disk and includes support means that couples the input shaft and the input disk in a rotational direction and allows axial displacement of the input disk. ,
The supporting means includes
A first groove formed on one of the input shaft and the input disk and parallel to the axis of the input shaft;
Formed on the other side of the input shaft or the input disk and facing the first groove, the groove width in the central portion in the axial direction is narrow, and the depth in the central portion in the axial direction is also made shallower and the groove width toward both ends. And a second groove of increasing depth;
A toroidal continuously variable transmission comprising a plurality of balls interposed between the first and second groove portions and allowing the input disk to tilt with respect to the input shaft.

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