JP2005003084A - Toroidal continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toroidal continuously variable transmission capable of lessening sliding resistance and controlling reduction of pushing force and controlling sliding on a traction surface. <P>SOLUTION: The toroidal continuously variable transmission comprises an input disk 32 and an output disk 36 supported on an input shaft 31, a plurality of power rollers 60 keeping into rolling contact between the input disk 32 and the outer disk 36 in a rolling-free state conveying power with friction, and a hydraulic loading device 34 pushing the input disk 32 and conveying rotary force onto the output disk 36 via the power rollers 60. The hydraulic loading device 34 is provided with a cylinder 71 forming an oil pressure chamber 70 between the input shaft 31 and the back of the input disk 32 integrally arranged, pistons 75 and 76 moving back and forth to an axial direction of the input shaft 31 by means of oil pressure arranged inside the cylinder 71, and a ball spline 83 as a sliding mechanism arranged on the outer periphery of the input disk 32 and the cylinder 70 and engaging them. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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, half-toroidal continuously variable transmissions used as transmissions for automobiles are mainly provided with a mechanical loading cam type pressing mechanism between an input shaft and an input disk. In this pressing mechanism, when the cam plate rotates with the rotation of the input shaft, the roller is pressed against the cam surface of the input disk by the cam surface, and the rotation of the input disk is transmitted to the output disk via the power roller. It has become.
[0003]
In addition, full-toroidal continuously variable transmissions that employ a pressing mechanism based on hydraulic loading are the mainstream. The pressing mechanism by hydraulic loading is provided with a cylinder constituting a hydraulic chamber on the back side of the input disk, and the input disk coupled to the input shaft by a ball spline is used as a piston component to apply a pressing force to the input disk. The cylinder and the input disk (piston component) are supported by the input shaft and rotate integrally with the input shaft (see, for example, Patent Document 1).
[0004]
In the case of the mechanical loading cam, a pressing force proportional to the input torque is generated. In addition, the hydraulic loading changes not only the input torque but also the pressing force depending on various conditions such as gear ratio and oil temperature, and can generate the pressing force according to the change. It leads to improvement.
[0005]
Further, a toroidal continuously variable transmission is known in which a ball spline is provided between the inner diameter side of the input disk and the input shaft (see, for example, Patent Documents 2 and 3).
[0006]
[Patent Document 1]
JP-T-6-502476 Publication [0007]
[Patent Document 2]
Japanese Patent Laid-Open No. 11-182645
[Patent Document 3]
Japanese Patent Laid-Open No. 2002-323103
[Problems to be solved by the invention]
However, in the toroidal-type continuously variable transmission, each part is greatly deformed by the pressing force of hydraulic pressure, but the power roller is supported by the displacement shaft so that the input disk and the power roller are in contact with each other depending on the amount of deformation. The disc and the input shaft are coupled by a ball spline so that the input disc can move smoothly in the axial direction.
[0010]
However, as shown in Patent Document 1, when a ball spline is provided on the input shaft, it is provided at a location where the shaft diameter is small, so that a large tangential force must be transmitted by the ball. Therefore, it is necessary to increase the number of balls and the number of spline grooves, and it is difficult to process and assemble. Further, since the spline groove is desired to be a through-groove for processing, it is a groove that penetrates from the front surface to the back surface of the input disk. Further, since the back surface of the input disk is a piston part, a seal part is required to prevent oil leakage.
[0011]
Furthermore, since the hole is formed in the input shaft to form an oil passage in the axial direction and the radial direction for lubrication of the ball spline, the hole becomes a stress concentration portion and may be damaged.
[0012]
In addition, as in Patent Documents 2 and 3, when the ball spline is provided between the inner diameter side of the input disk and the input shaft, the inner diameter side of the input disk has a large tangential force and the power transmission capability of the ball spline is increased. There is a need to. Further, there is a problem that stress concentration occurs in a portion where the spline groove of the input shaft is provided, and durability is low.
[0013]
The present invention has been made paying attention to the above circumstances, and an object thereof is to engage an input disk and a cylinder so as to be slidable in an axial direction in a toroidal continuously variable transmission having a hydraulic loading mechanism. By doing so, both of them can be transmitted at a large diameter, the tangential force can be kept small, an appropriate pressing force is applied to the traction surface to suppress the slip, and this sliding part is a ball spline. Provides a toroidal continuously variable transmission that can further reduce the tangential force, reduce the number of balls and grooves on the ball spline, facilitate machining and assembly, and improve durability by reducing stress. There is to do.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an input shaft, an input disk and an output disk that are rotatably supported by the input shaft concentrically and independently of each other, and the input disk. And a trunnion that exists at a twisted position that is perpendicular to the direction of the central axis of the output disk, and a trunnion that swings about the pivot, and a displacement shaft that is rotatably supported by the trunnion, A plurality of power rollers sandwiched between the traction surfaces of the input disk and the output disk in a state of being rotatably supported by the displacement shaft, and the output disk via the power roller by pressing the input disk In a toroidal continuously variable transmission having a hydraulic loading mechanism for transmitting rotational force to a disc, the hydraulic loading mechanism is integrated with the input shaft. A cylinder that is provided and forms a hydraulic chamber between the back surface of the input disk, a piston that is provided inside the cylinder and moves forward and backward in the axial direction of the input shaft by hydraulic pressure, and the input disk and the cylinder. It is characterized by comprising a sliding mechanism that engages both.
[0015]
A second aspect of the present invention is characterized in that the sliding mechanism of the first aspect is a ball spline. According to a third aspect of the present invention, there is provided a lubricating oil supply passage for supplying the lubricating oil in the hydraulic chamber to the ball spline on the outer peripheral portion of the input disk of the second aspect.
[0016]
According to the above configuration, by engaging the input disk and the cylinder with the sliding mechanism, it is not necessary to provide an engagement mechanism between the input shaft and the input disk, and the tangential force can be suppressed to be small. Slip can be suppressed by applying an appropriate pressing force to the surface.
[0017]
Further, by making this sliding portion a ball spline, the tangential force is further reduced, and the number of balls and grooves of the ball spline can be reduced. Also, the ball spline can be lubricated by oil leakage from the hydraulic chamber, eliminating the need for drilling holes for the oil passages on the input shaft, leading to stress reduction and downsizing of the toroidal continuously variable transmission, Weight reduction can be achieved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0019]
1 and 2 show a first embodiment. FIG. 1 is a longitudinal side view of a double cavity type toroidal continuously variable transmission, and FIG. 2 is a longitudinal front view of the same.
[0020]
As shown in FIG. 1, first and second input disks 32 and 33 are disposed near both ends of the input shaft 31 with the traction surfaces 32 a and 33 a facing each other. A hydraulic loading device 34 to be described later is provided on the back side of the first input disk 32, and the second input disk 33 is fixed to the input shaft 31 by a loading nut 35. Accordingly, the first and second input disks 32 and 33 rotate concentrically and in synchronization with each other.
[0021]
First and second output disks 36 and 37 are disposed around the intermediate portion of the input shaft 32, and one side of the first and second output disks 36 and 37 is supported via a sleeve 38. . The sleeve 38 has an output gear 39 integrally provided on the outer peripheral surface of the intermediate portion, has an inner diameter larger than the outer diameter of the input shaft 31, and is input to a gear housing 40 provided in the case by a pair of ball bearings 41. It is supported so as to be rotatable concentrically with the shaft 31.
[0022]
In the vicinity of both ends of the sleeve 38, a belt-like annular groove 42 is provided in the circumferential direction on the outer peripheral surface of the input shaft 31. A needle bearing 43 is accommodated in the annular groove 42 so as not to move in the axial direction, and the needle bearing 43 rotatably supports the other side portions of the first and second output disks 36 and 37.
[0023]
Therefore, even if a large pressing load is applied to the first and second output disks 36 and 37 by power transmission from a power roller, which will be described later, the first and second output disks 36 and 37 are inserted into the annular groove of the input shaft 31. Since it is supported by the needle bearing 43 which is accommodated in the axial direction so as not to move, the stress of the first and second output disks 36 and 37 is reduced, and local stress concentration can be avoided.
[0024]
The first and second output disks 36 and 37 are splined to both ends of the sleeve 38 so that the traction surfaces 36a and 37a face each other. Accordingly, the first input disk 32 and the first output disk 36 have the traction surfaces 32a and 36a facing each other, and the second input disk 33 and the second output disk 37 have the traction surfaces 33a and 37a facing each other. It is supported so that it can rotate freely.
[0025]
Between the traction surface 32 a of the first input disk 32 and the traction surface 36 a of the first output disk 36, a first cavity 46 is formed between the traction surface 33 a of the second input disk 33 and the second output disk 37. A second cavity 47 that is a portion between the traction surface 37a is provided.
[0026]
The first and second cavities 46 and 47 are provided with projecting support members 48 fixed to a case (not shown). The support member 48 is provided with a pair of support legs 49 spaced apart from each other, and the support legs 49 are provided with through holes 51 for fixing both ends of the pin 50. An intermediate portion of the upper yoke 52 a and the lower yoke 52 b is pivotally supported with respect to the pin 50 between the pair of support legs 49.
[0027]
As shown in FIG. 2, upper and lower pivot shafts 55 of a pair of trunnions 54 are supported at the ends of the upper yoke 52a and the lower yoke 52b so as to be swingable and displaceable in the axial direction.
[0028]
Displacement shafts 56 are supported at intermediate portions of the trunnions 54, respectively. The displacement shaft 56 has a support shaft portion 57 and a pivot shaft portion 58 that are parallel to each other and eccentric. Of these, the support shaft portion 57 is supported by the trunnion 54 via a radial needle bearing 59. A power roller 60 is supported around the pivot shaft 58 via a radial bearing 60a. Further, the power roller 60 is supported by a thrust ball bearing 61. The thrust ball bearing 61 allows rotation of the power roller 60 while supporting a load in the thrust direction applied to the power roller 60.
[0029]
The plurality of balls 61a of the thrust ball bearing 61 are held by an annular cage 63 provided between an annular outer ring 62 provided on the trunnion 54 side and a power roller 60 as a rotating portion. Yes.
[0030]
The power roller 60 has a traction portion in contact with the first and second input disks 32 and 33 and the first and second output disks 36 and 37, and the first and second input disks 32 and 33 and the first The first and second output disks 36 and 37 are in contact with each other in a tiltable manner.
[0031]
Further, the lower pivot 55 of the trunnion 54 is provided with a wire pulley 65 having two wire grooves 64a and 64b. The wire grooves 64a and 64b have eight synchronization wires 66a and 66b for connecting the left and right and front and rear. Crossed in a letter shape. The synchronization wires 66a and 66b serve to synchronize the tilting (swinging about the pivot 55) of the trunnion 54 with each other.
[0032]
Further, a hydraulic piston 67 is provided below the trunnion 54, and the trunnion 54 can be moved up and down by giving a pressure difference to the hydraulic piston 67. That is, the trunnion 54 is stroked in the direction of the swing axis O ₂ orthogonal to the axis O ₁ of the power roller 60 under the guidance of the upper yoke 52 a and the lower yoke 52 _b, and the power roller 60 and the trunnion 54 around the swing axis O _2. Tilt. As a result, the transmission ratio between the input disks 32 and 33 and the output disks 36 and 37 is changed steplessly to change the speed.
[0033]
The hydraulic loading device 34 is configured as shown in FIG. That is, a cylinder 71 that forms a hydraulic chamber 70 is integrally provided at the end of the input shaft 31 on the drive shaft side on the back side of the first input disk 32. A small-diameter portion 72 is provided near the first input disk 32 of the input shaft 31 located inside the hydraulic chamber 70, and a large-diameter portion 73 is provided near the back surface of the cylinder 71, and a step 74 is formed therebetween. Has been.
[0034]
A first piston 75 having a disc shape and having a sealing material 75a on the outer peripheral surface is fitted in the small diameter portion 72 so as to be movable in the axial direction, and the first input disk 32 is interposed between the first input disk 32 and the rear surface. One hydraulic chamber 70a is formed. A second piston 76 having a disc shape and having a sealing material 76 a on the outer peripheral surface is fitted in the large diameter portion 73 so as to be movable in the axial direction, and the second hydraulic chamber 70 b is interposed between the rear surface of the cylinder 71. Is formed.
[0035]
Further, a disc spring 77 is provided between the back surface of the cylinder 71 and the second piston 76. In addition, an air chamber 70 c communicating with the atmosphere is formed between the first piston 75 and the second piston 76.
[0036]
A movable cylinder 78 having an annular shape having a large diameter cylindrical portion 78a and a small diameter cylindrical portion 78b is provided on the outer peripheral portion of the first input disk 32. The large-diameter cylindrical portion 78a of the movable cylinder 78 is fitted to the outer peripheral portion of the first input disk 32, and the inner peripheral surface of the large-diameter cylindrical portion 78a and the outer peripheral surface of the first input disk 32 in this fitting portion. A concave / convex groove 79 is provided between the movable cylinder 78 and the movable cylinder 78 so as to be movable in the axial direction and immovable in the circumferential direction.
[0037]
In addition, the sealing material 75a of the first piston 75 comes into contact with the inner peripheral surface of the small diameter cylindrical portion 78b of the movable cylinder 78 to seal the first hydraulic chamber 70a, and the end surface of the small diameter cylindrical portion 78b is the second piston. 76 is in contact with the outer peripheral side surface of 76. The sealing material 76a of the second piston 76 contacts the inner peripheral surface of the cylinder 71, and the second hydraulic chamber 70b is sealed.
[0038]
Further, a plurality of spline grooves 80 are provided on the outer peripheral surface of the movable cylinder 78 at equal intervals in the circumferential direction so as to penetrate in the axial direction. A spline groove 81 corresponding to the spline groove 80 of the movable cylinder 78 is provided on the inner peripheral surface of the cylinder 71. A plurality of balls 82 are interposed between the spline grooves 80 and 81 to constitute a ball spline 83 which is a sliding mechanism.
[0039]
An oil passage 84 is provided in the axial direction in the axial center portion of the input shaft 31. The oil passage 84 communicates with the first hydraulic chamber 70a and the second hydraulic chamber 70b via a branch oil passage 85 penetrating in the radial direction.
[0040]
When the hydraulic pressure is supplied from the hydraulic pressure supply source during the operation of the double cavity type toroidal continuously variable transmission configured as described above, the first hydraulic chamber 70a and the second hydraulic pressure chamber 70a and the second hydraulic pressure path 85 are connected via the oil path 84 and the branch oil path 85. Hydraulic pressure is simultaneously applied to the hydraulic chamber 70b. Accordingly, the first input disk 32 is moved forward (pressed toward the first output disk 6) by the hydraulic pressure of the first hydraulic chamber 70a, and the first piston 75 is moved by the hydraulic pressure of the first hydraulic chamber 70a. Retreat in the direction of the second piston 76. As the first piston 75 retreats, the first piston 75 presses the step 74, so the input shaft 31 retreats and the second input disk 33 moves toward the second output disk 37.
[0041]
Further, since the second piston 76 is advanced (pressed toward the first piston 75) by the hydraulic pressure of the second hydraulic chamber 70b, the first input disk 32 is advanced (first first) via the movable cylinder 78. Press the output disk 6 side). At this time, since the movable cylinder 78 is supported by the cylinder 71 via the ball spline 83, it moves forward smoothly.
[0042]
Accordingly, the rotation of the input shaft 31 is transmitted to the first input disk 32, and the first input disk 32 and the second input disk 33 rotate in synchronization with each other. The rotation of the first input disk 32 and the second input disk 33 is transmitted to the first and second output disks 36 and 37 via the power roller 60. The rotations of the first and second output disks 36 and 37 are transmitted to the output gear 39 and taken out by an output shaft (not shown) via the transmission gear.
[0043]
When changing the rotational speed ratio between the input shaft 31 and the output gear 39, a pair is provided corresponding to each of the first and second cavities 46 and 47 based on switching of control valves (not shown). The hydraulic piston 67 is displaced by the same distance in the opposite directions for each of the cavities 46 and 47.
[0044]
Along with the displacement of these hydraulic pistons 67, a total of four trunnions 54 are displaced in the opposite direction, and one power roller 60 is displaced downward and the other power roller 60 is displaced upward. As a result, the circumferential surface of each power roller 60 contacts the traction surfaces 32a and 33a of the first and second input disks 32 and 33 and the traction surfaces 36a and 37a of the first and second output disks 36 and 37. The direction of the tangential force acting on the part changes. As the direction of the force changes, the trunnion 54 swings in the reverse direction around the pivot 55 pivotally supported by the upper yoke 52a and the lower yoke 52b. As a result, the contact position between the peripheral surface of the power roller 60 and the first and second input disks 32 and 33 and the first and second output disks 36 and 37 changes, and the input shaft 31 and the output gear 39 are in contact with each other. Rotational speed ratio in between changes.
[0045]
Thus, by engaging the outer peripheral portion of the first input disk 32 and the cylinder 71 with the ball spline 83, there is no need to provide a ball spline between the input shaft 31 and the first input disk 32. The tangential force is small, and the number of balls and grooves of the ball spline 83 can be reduced.
[0046]
Further, since there is no need to provide a ball spline on the input shaft 31, stress concentration on the inner diameter portion of the first input disk 32 and the input shaft 31 is eliminated, and the size can be reduced. Further, the inner diameter of the disk is deformed into an ellipse as disclosed in JP-A-11-141564. For this reason, when a ball spline is provided on the inner diameter portion of the disk as in the prior art, it is necessary to consider the separation of the ball due to the occurrence of a piece hitting, etc. It can receive a load evenly, and there is no worry about occurrence of a piece hitting or peeling of a ball.
[0047]
Further, by providing the ball spline 83 on the outer periphery from the hydraulic chamber 70 of the hydraulic loading device 34, it is not necessary to provide a seal, and lubrication can be performed by oil leakage from the hydraulic chamber 70. Further, it is not necessary to drill the hole for the oil passage in the input shaft 31, which leads to stress reduction, the input shaft 31 can be reduced in diameter, and the toroidal continuously variable transmission can be reduced in size and weight. .
[0048]
FIG. 3 shows a second embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the hydraulic loading device 34 of the present embodiment, a spline groove 87 is directly provided on the outer peripheral portion of the first input disk 32 corresponding to the spline groove 81 provided on the inner peripheral surface of the cylinder 71. A plurality of balls 82 are interposed between the spline grooves 81 and 87 to form a ball spline 88.
[0049]
Further, a concave groove 86 as a lubricating oil supply passage is provided in a radial direction at a position corresponding to the spline groove 87 on the back surface of the outer peripheral portion of the first input disk 32. Therefore, the air chamber 70c and the ball spline 88 communicate with each other via the concave groove 86, and the concave groove 86 is in the air chamber 70c due to pressure fluctuations when the first and second pistons 75 and 76 move forward and backward. Lubricating oil is supplied to the ball spline 88.
[0050]
According to the present embodiment, in addition to the effects of the first embodiment, by providing the spline groove 87 directly on the outer peripheral portion of the first input disk 32, the hydraulic loading device 34 does not need a movable cylinder and is further downsized. It is possible to reduce the weight.
[0051]
In the above-described embodiment, the hydraulic loading device is a double piston so that the hydraulic pressure can be lowered. However, a single piston has the same effect. Moreover, although the double cavity type has been described, it can also be applied to a single cavity type toroidal type continuously variable transmission.
[0052]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the power to the input disk can be transmitted and the coupling of the sliding parts can be transmitted at a large diameter, the tangential force is reduced and the sliding force is reduced. The dynamic resistance is reduced, the pressing force can be prevented from decreasing, and the traction surface can be prevented from slipping.
[0053]
Furthermore, according to the invention of claim 2, by arranging the ball spline in the sliding portion of claim 1, the sliding resistance can be reduced, and the number of balls and grooves of the ball spline can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a double cavity type toroidal continuously variable transmission according to a first embodiment of the present invention.
FIG. 2 is a longitudinal front view of a double cavity toroidal continuously variable transmission according to the embodiment.
FIG. 3 is a longitudinal side view showing a part of a hydraulic loading device according to a second embodiment of the present invention.
[Explanation of symbols]
31 ... Input shaft, 32,33 ... Input disk, 34 ... Hydraulic loading device, 36,37 ... Output disk, 54 ... Trunnion, 60 ... Power roller, 70 ... Hydraulic chamber, 71 ... Cylinder, 75,76 ... Piston, 83 , 85 ... Ball spline

Claims (3)

An input shaft, an input disc and an output disc supported concentrically and independently of each other by the input shaft, and a twisting direction perpendicular to the direction of the central axis of the input disc and the output disc A trunnion having a pivot shaft at a position and swinging about the pivot shaft; a displacement shaft rotatably supported by the trunnion; and the input disk and the output in a state of being rotatably supported by the displacement shaft A toroidal-type stepless unit comprising a plurality of power rollers sandwiched between traction surfaces of a disc, and a hydraulic loading mechanism that presses the input disc and transmits a rotational force to the output disc via the power roller. In the transmission,
The hydraulic loading mechanism is provided integrally with the input shaft and forms a hydraulic chamber between the input disk and the back surface of the input disk, and is provided inside the cylinder and advances and retreats in the axial direction of the input shaft by hydraulic pressure. A toroidal-type continuously variable transmission comprising a piston and a sliding mechanism that is provided on the input disk and the cylinder and engages them. The toroidal continuously variable transmission according to claim 1, wherein the sliding mechanism is a ball spline. 3. The toroidal continuously variable transmission according to claim 2, wherein a lubricating oil supply passage for supplying lubricating oil in the hydraulic chamber to the ball spline is provided on an outer peripheral portion of the input disk.

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