JP5573104B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to a toroidal continuously variable transmission that can be used for transmissions of automobiles and various industrial machines.

  The use of a toroidal type continuously variable transmission as shown in FIGS. 3 to 5 as an automatic transmission for automobiles has been studied and implemented in part. This toroidal type continuously variable transmission is called a double cavity type, and supports input-side disks 2 and 2 around both ends of the input shaft 1 via ball splines 3 and 3. Therefore, both the input side disks 2 and 2 are supported concentrically and freely in a synchronized manner. An output gear 4 is supported around the intermediate portion of the input shaft 1 so as to be freely rotatable relative to the input shaft 1. The output side disks 5 and 5 are respectively spline-engaged with both ends of a cylindrical portion provided at the center of the output gear 4. Accordingly, both the output side disks 5 and 5 rotate in synchronism with the output gear 4.

  A plurality (usually 2 to 3) of power rollers 6 and 6 are sandwiched between the input disks 2 and 2 and the output disks 5 and 5, respectively. Each of these power rollers 6 and 6 is rotatably supported by inner surfaces of trunnions 7 and 7 via support shafts 8 and 8 and a plurality of rolling bearings, respectively. The trunnions 7 and 7 are pivots 9a and 9b provided concentrically with each other for each trunnion 7 and 7 at both ends in the length direction (the vertical direction in FIGS. 3 and 5 and the front and back direction in FIG. 4). Oscillating and displacing around the center. The operation of inclining the trunnions 7 and 7 is performed by displacing the trunnions 7 and 7 in the axial direction of the pivots 9a and 9b by the hydraulic actuators 10 and 10. The inclination angle of 7 is synchronized with each other hydraulically and mechanically.

  That is, when changing the inclination angle of the trunnions 7 and 7 in order to change the transmission ratio between the input shaft 1 and the output gear 4, the trunnions 7 and 7 are moved by the actuators 10 and 10. In the opposite directions (same direction with respect to the rotation direction of the disks 2 and 5), for example, the right side power roller 6 in FIG. 5 is on the lower side and the left side power roller 6 in FIG. Respectively. As a result, the direction of the tangential force acting on the contact portion between the peripheral surface of each of the power rollers 6 and 6 and the inner surface of each of the input side disks 2 and 2 and the output side disks 5 and 5 changes. (Side slip occurs at the contact portion). The trunnions 7 and 7 swing (tilt) in opposite directions around the pivots 9a and 9b pivotally supported by the support plates 11 and 11 in accordance with the change in the direction of the force. As a result, the contact position between the peripheral surface of each of the power rollers 6 and 6 and the inner surface of each of the input and output disks 2 and 5 changes, and rotation between the input shaft 1 and the output gear 4 occurs. The gear ratio changes.

  Regardless of the number of these actuators 10, 10, the supply / discharge state of the pressure oil to each of the actuators 10, 10 is performed by one control valve 12, and any one trunnion 7 is moved. I'm trying to provide feedback. This control valve 12 is fitted into a sleeve 14 that is displaced in the axial direction (front and back direction in FIG. 3, left and right direction in FIG. 5) by a stepping motor 13, and axially displaceable on the inner diameter side of the sleeve 14. And a spool 15. The trunnions 7 and 7 are connected to the pistons 16 and 16 of the actuators 10 and 10. The rods 17 and 17 are used to transmit the movements of the pistons 16 and 16 to the trunnions 7 and 7, respectively. Among them, a recess cam 18 is fixed to an end of a rod 17 attached to any one trunnion 7. A feedback mechanism is configured to transmit the movement of the rod 17, that is, the combined value of the displacement amount in the axial direction and the displacement amount in the rotation direction, to the spool 15 via the recess cam 18 and the link arm 19. doing. Moreover, the synchronous cable 20 is spanned between a pair of trunnions 7 and 7 installed in the same cavity part (between the input side disk 2 and the output side disk 5 facing each other), The inclination angles of these trunnions 7, 7 are mechanically synchronized. A synchronization cable (not shown) is also routed between the trunnions 7, 7 installed in different cavities.

  When switching the speed change state, the stepping motor 13 displaces the sleeve 14 to a predetermined position corresponding to the speed ratio to be obtained, and opens the flow path of the control valve 12 in a predetermined direction. As a result, pressure oil is sent to the actuators 10 and 10 in a predetermined direction, and the actuators 10 and 10 displace the trunnions 7 and 7 in a predetermined direction. That is, the trunnions 7 and 7 swing around the pivots 9a and 9b while being displaced in the axial direction of the pivots 9a and 9b as the pressure oil is fed. Then, the movement (axial direction and swing displacement) of any one of the trunnions 7 is transmitted to the spool 15 via a recess cam 18 and a link arm 19 fixed to the end of the rod 17, and this spool 15 is displaced in the axial direction. As a result, in the state where the trunnion 7 is displaced by a predetermined amount, the flow path of the control valve 12 is closed, and the supply and discharge of the pressure oil to the actuators 10 and 10 are stopped.

  During operation of the toroidal type continuously variable transmission as described above, one input side disk 2 (left side in FIGS. 3 and 4) is connected to a loading cam type as shown by a drive shaft 21 connected to a power source such as an engine. Alternatively, it is rotationally driven via a hydraulic pressing device 22. As a result, the pair of input side disks 2 and 2 supported at both ends of the input shaft 1 rotate synchronously while being pressed toward each other. Then, the rotation is transmitted to the output side disks 5 and 5 through the power rollers 6 and 6 and is taken out from the output gear 4.

  When the rotational speed of the input shaft 1 and the output gear 4 is changed, and when the deceleration is first performed between the input shaft 1 and the output gear 4, the trunnions 7 and 7 are moved by the actuators 10 and 10, respectively. The trunnions 9 and 9b are moved in the axial direction to swing the trunnions 7 and 7. The peripheral surfaces of the power rollers 6 and 6 are brought into contact with the central portion of the inner surface of the input side disks 2 and 2 and the outer peripheral portion of the inner surface of the output disks 5 and 5, respectively. Let On the other hand, when increasing the speed, the trunnions 7 and 7 are swung in the reverse direction, and the peripheral surfaces of the power rollers 6 and 6 are set to the outer periphery of the inner surfaces of the input disks 2 and 2. The trunnions 7 and 7 are inclined so as to come into contact with the portions closer to the center of the inner side surfaces of the output side disks 5 and 5 respectively. If the inclination angles of these trunnions 7 and 7 are set in the middle, the intermediate speed ratio (speed ratio) between the input shaft 1 and the output gear 4 including the constant speed transmission state as shown in FIG. can get.

  By the way, during operation of the toroidal type continuously variable transmission configured as described above, the pressing force required for the pressing device to press the input side disk against the output side disk is the magnitude of the torque to be transmitted. Not only changes depending on the speed, but also changes depending on the gear ratio. That is, when the trunnion is oscillated and displaced about the pivot to change the gear ratio, the position of the traction portion that is the contact point between the peripheral surface of each power roller and the inner side surface of each disk changes. And with the position change of this traction part, the pressing force required in order to give required pressing force to this traction part changes. Specifically, assuming that the torque to be transmitted is constant, as shown by a solid line α in FIG. 6, the rotational force is transmitted between the input side disk and the output side disk at substantially constant speed ( When the gear ratio is in the vicinity of 1, the required pressing force is the largest. On the other hand, as the trunnion is tilted and the reduction ratio or speed increase ratio between the input side disk and the output side disk increases, the required pressing force decreases.

  On the other hand, the loading cam device incorporated as a pressing device in the conventional structure shown in FIGS. 3 to 5 generates a pressing force according to the magnitude of torque to be transmitted. Even if other factors change, the generated pressing force does not change. For this reason, in the case of a conventional structure having only a loading cam device as a pressing device, the pressing force generated by this loading cam device has a gear ratio that requires the largest pressing force as shown by the broken line β in FIG. It is set in accordance with the case of the vicinity of 1. Therefore, in the case of such a conventional structure, when the gear ratio is other than near 1, the pressing force generated by the loading cam device becomes excessive, and the extent to which the pressing force is excessive increases the reduction ratio or the increase. The greater the speed ratio, the more significant it becomes. When the pressing force becomes excessive and the pressing force of the traction portion becomes excessive, not only the transmission efficiency in the traction portion is deteriorated, but also the rolling fatigue life of each surface constituting the traction portion is shortened.

  In view of such circumstances, Patent Document 1 (Japanese Patent Laid-Open No. 2003-028257) discloses that a pressing device that is incorporated in a toroidal-type continuously variable transmission and generates a pressing force includes a loading cam device and a hydraulic actuator. The loading cam device generates a pressing force in a direction in which the input side disc and the output side disc are brought close to each other, and the hydraulic actuator is a pressing force in a direction in which the input side disc and the output side disc are moved away from each other. The structure that is supposed to generate is described.

JP 2003-028257 A

  In the case of the structure as described in the above-mentioned patent document, since the hydraulic actuator is provided between the input side disk and the loading cam device, it is necessary to form a spline on the outer diameter of the disk. Will become longer. Further, since the hydraulic actuator rotates together with the input shaft, there is a possibility of being affected by centrifugal hydraulic pressure when rotating at high speed. In view of such circumstances, an object of the present invention is to provide a structure capable of shortening an axial dimension and capable of giving an optimum pressing force without being affected by centrifugal hydraulic pressure even under high-speed rotation conditions. And

To achieve the above object, the toroidal continuously variable transmission according to claim 1 rotates concentrically with each other, each of which is a concave surface having an arcuate cross section facing each other. A freely supported input side disk and output side disk, a plurality of trunnions that swing about a pivot that is twisted with respect to the center axis of the input side disk and the output side disk, and an intermediate portion of each trunnion In addition, the displacement shaft supported in a state protruding from the inner side surface of each trunnion, and the above-mentioned each of the trunnions disposed on the inner side surface of each trunnion and sandwiched between the input side disk and the output side disk A force roller that is supported rotatably around the displacement shaft and has a spherical convex surface, and a force in a direction in which the input side disk and the output side disk approach each other. In the toroidal type continuously variable transmission having a pressing device for applying,
The input side disk and the output by the pressing device act between the input side disk and the post between the input side disk and the output side disk and act on the post supporting the support plate on which the pivot shaft of the trunnion is pivotally supported. A hydraulic chamber is provided that cancels the force in the direction in which the side disks approach each other .

  According to the present invention, the axial dimension of the toroidal-type continuously variable transmission can be shortened, and an optimum pressing force can be applied without being affected by centrifugal hydraulic pressure even under high-speed rotation conditions.

The figure which shows the 1st example of embodiment of this invention. The figure which shows the 2nd example of embodiment of this invention. Sectional drawing which shows an example of the conventional toroidal type continuously variable transmission. 3A-A sectional view. FIG. 3B-B sectional view. The diagram which shows the relationship between the magnitude of the pressing force which the conventionally known pressing device generate | occur | produces, and a gear ratio.

  FIG. 1 shows a first example of an embodiment of the present invention. The feature of the present invention is to secure the pressing force of the traction surface which is a contact portion between the inner surface of each of the input side disks 2 and 2 and the output side disks 5 and 5 and the peripheral surface of each of the power rollers 6 and 6. In the structure of the pressing device, one input side disk is pressed toward the other input side disk. The structure and operation of the other parts are the same as those of the conventionally known toroidal continuously variable transmission including the structure shown in FIGS. Therefore, illustrations and descriptions relating to parts equivalent to those of the conventional structure are omitted or simplified, and the following description will focus on the features of the present invention.

  In the case of the pressing device constituting the toroidal type continuously variable transmission of this example, a hydraulic chamber 24 constituting the pressing device together with the loading cam device 23 is provided between the input side disks 2 and 2 and the output side disks 5 and 5. ing.

  Specifically, an annular recess 26 having an opening on the input side disk side is provided at the center of a post 25 that supports the support plate 11 (not shown), and an annular piston plate 27 is disposed on the opened side to provide hydraulic pressure. The chamber 24 is configured. The space between the inner peripheral surface of the piston plate 27 and the outer peripheral surface of the recess and the space between the outer peripheral surface of the piston plate 27 and the inner peripheral surface of the recess are oil-tightly closed by seal rings, respectively. The hydraulic pressure is supplied by an oil passage 29 formed in the post.

  Further, a bearing (sliding bearing or thrust needle bearing) 28 is provided between the input side disk 2 and the piston plate 27 so as to inhibit the rotation of the input side disk.

  By adopting such a configuration, an optimum pressing force can be given by canceling the excessive pressing force caused by the loading cam device 23 when the transmission gear ratio is different or the excessive pressing force due to the disc spring by the hydraulic chamber 24. Can do. And the best transmission efficiency is obtained, the rolling life of the traction surface can be prevented from being reduced, and the durability is improved. Further, since the hydraulic chamber does not rotate, it is not necessary to consider the influence of the centrifugal hydraulic pressure, so that the control becomes simple.

  FIG. 2 shows a second example of the embodiment of the present invention. In the case of this example, a hydraulic actuator 30 is used instead of the loading cam device 23 of the first example of the embodiment. Other configurations are the same as those of the first example of the embodiment.

  By adopting such a configuration, an optimum pressing force can be given by canceling the excessive pressing force due to the centrifugal hydraulic pressure generated in the hydraulic actuator 30 or the excessive pressing force due to the disc spring at the time of high-speed rotation by the hydraulic chamber 24. Can do. And the best transmission efficiency is obtained, the rolling life of the traction surface can be prevented from being reduced, and the durability is improved. Further, since the hydraulic chamber does not rotate, it is not necessary to consider the influence of the centrifugal hydraulic pressure, so that the control becomes simple.

1 Input shaft
2 Input disk
3 Ball spline
4 Output gear
5 Output disk
6 Power roller
7 Trunnion
8 Support shaft
9, 9a, 9b Axis
10 Hydraulic actuator
11 Support plate
12 Control valve
13 Stepping motor
14 sleeve
15 spool
16 piston
17 Rod
18 Precess Come
19 Link arm
20 Sync cable
21 Drive shaft
22 Pressing device
23 Loading cam device
24 Hydraulic chamber
25 post
26 Recess
27 Piston plate
28 Bearing
29 Oilway
30 Hydraulic actuator

Claims (1)

An input side disk and an output side disk that are supported concentrically and rotatably in a state in which the inner side surfaces, which are concave surfaces each having a circular arc shape, are opposed to each other, and these input side disk and output side disk A plurality of trunnions that swing about a pivot axis that is twisted with respect to the central axis of the shaft, a displacement shaft that is supported in a state protruding from the inner surface of each trunnion, and each of these trunnions A power roller disposed on the inner side of the trunnion and supported rotatably around each displacement shaft in a state of being sandwiched between the input-side disk and the output-side disk and having a circumferential convex surface. And a toroidal continuously variable transmission including a pressing device that applies a force in a direction in which the input side disk and the output side disk approach each other,
The input side disk and the output by the pressing device act between the input side disk and the post between the input side disk and the output side disk and act on the post supporting the support plate on which the pivot shaft of the trunnion is pivotally supported. A toroidal continuously variable transmission, characterized in that a hydraulic chamber is provided for canceling the force in the direction in which the side disks approach each other .

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