JP2007298098A - Toroidal type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a structure capable of quickly (accurately) detecting an excessive slip (exceeding a slip based on power transmission), when the slip is generated in a plurality of power rollers 13, 13 composing a toroidal type continuously variable transmission. <P>SOLUTION: The tilting angles of respective trunnions supporting the respective power rollers 13, 13 and at least one of the rotation speeds of the respective power rollers 13, 13 are measured. The tilting angles and the rotation speeds are compared by a comparison means, and when either one of the tilting angles of the trunnions or either one of the rotation speeds of the power rollers 13 exceeds the tilting angles and the threshold value of the other trunnions or the rotation speeds and the threshold value of the other power rollers 13 and differs from them, it is determined that the excessive slip is generated in the contact parts of the respective inside faces 3, 12 of both input and output side discs 2a, 2b, 11 which hold the peripheral surface 14 of the power roller 13 and the power roller 13 between them. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The toroidal continuously variable transmission according to the present invention is used, for example, as a transmission unit constituting an automatic transmission for automobiles or as a transmission for adjusting the operating speed of various industrial machines such as pumps.

  For example, as described in Patent Documents 1 to 3, etc., it has been studied to use a toroidal continuously variable transmission as shown in FIGS. 3 to 5 as a transmission unit of an automatic transmission for an automobile. It has been implemented. The toroidal type continuously variable transmission shown in FIGS. 3 to 5 is called a double cavity type, and supports a pair of input side disks 2 a and 2 b at both ends of the input rotating shaft 1. These input side disks 2a and 2b are each a toroidal curved surface (concave arc-shaped concave surface) with respect to the input rotation shaft 1, and the input side inner surface corresponding to one axial side surface recited in the claims. 3 and 3 are supported via ball splines 4 and 4 in a state of being opposed to each other. Therefore, both the input side disks 2a and 2b are supported concentrically and freely in a synchronized manner.

  Further, the intermediate portion of the input rotary shaft 1 is inserted through a through hole 7 provided in a partition wall portion 6 installed in a casing 5 housing a toroidal type continuously variable transmission. A cylindrical output cylinder 8 is rotatably supported by a pair of rolling bearings 9 and 9 on the inner diameter side of the through hole 7, and an output gear 10 is fixed to the outer peripheral surface of the intermediate portion of the output cylinder 8. Has been established. In addition, a pair of output side disks 11 and 11 are supported at both ends of the output cylinder 8 at portions projecting from both outer side surfaces of the partition wall 6 so as to be rotatable in synchronization with the output cylinder 8 by spline engagement. is doing. In this state, the output side inner surfaces 12 and 12 of the both output side disks 11 and 11, each of which is a toroidal curved surface and corresponding to one axial side surface recited in the claims, are both input side inner side surfaces. 3 and 3 are opposed.

  In addition, a plurality (generally two or three) of power rollers 13 are provided in the portion (cavity) between the input side and output side inner side surfaces 3 and 12 around the input rotary shaft 1. , 13 are arranged. Each of the power rollers 13 and 13 has a spherical convex surface on the peripheral surfaces 14 and 14 contacting the input side and output side inner side surfaces 3 and 12, and corresponds to the support member described in the claims. Support shafts 16 and 16, radial needle bearings 17 and 17, thrust ball bearings 18 and 18 and thrust needle bearings 19 and 19 can be rotated and slightly oscillated and displaced on the inner side surfaces of the trunnions 15 and 15. It is supported.

  That is, each of the support shafts 16 and 16 is an eccentric shaft in which the base half portion and the tip half portion are eccentric from each other, and the base half portion of the support shafts 16 and 16 is provided in the middle portion of the trunnions 15 and 15 as another radial needle bearing. 20 and 20 are supported so as to be swingable and displaceable. The power rollers 13 and 13 are rotatably supported on the front half portions of the support shafts 16 and 16 by the radial needle bearings 17 and 17 and the thrust ball bearings 18 and 18, respectively. Further, the displacement of each of the power rollers 13 and 13 with respect to the axial direction of the input rotary shaft 1 based on the elastic deformation of each constituent member is changed to the other radial needle bearings 20 and 20 and the thrust needle bearings 19 and 19. Because of this, it is free.

  Each trunnion 15, 15 has a pivot 21 provided concentrically with each other for each trunnion 15, 15 at both ends in the length direction (front and back direction in FIG. 4, vertical direction in FIGS. 3, 5). 21 can be oscillated and displaced freely. The operation of swinging (tilting) the trunnions 15 and 15 is performed by displacing the trunnions 15 and 15 in the axial direction of the pivots 21 and 21 by hydraulic actuators 22 and 22. At the time of shifting, the trunnions 15 and 15 are displaced in the axial direction of the pivots 21 and 21 by supplying and discharging pressure oil to and from the actuators 22 and 22, respectively. As a result, contact portions (traction portions) between the peripheral surfaces 14 and 14 of the power rollers 13 and 13 and the input and output inner surfaces 3 and 12 of the input and output disks 2a, 2b and 11 respectively. Since the direction of the force acting in the tangential direction changes, the trunnions 15 and 15 are oscillated and displaced about the pivots 21 and 21, respectively.

  During the operation of the toroidal type continuously variable transmission as described above, the drive shaft 23 connected to the power source of the engine or the like is used to connect one input side disk 2a (to the left in FIGS. 3 to 4) with the loading cam type pressing device 24. To rotate through. As a result, the pair of input-side disks 2a and 2b supported at both ends of the input rotation shaft 1 rotate synchronously while being pressed in a direction approaching each other. Then, this rotation is transmitted to the output side disks 11 and 11 through the power rollers 13 and 13 and is taken out from the output gear 10. Patent Document 2 describes a toroidal continuously variable transmission incorporating a hydraulic pressing device. In the case of a mechanical pressing device such as a loading cam, the pressing force generated by the pressing device is proportional to the torque transmitted by the toroidal continuously variable transmission. On the other hand, in the case of a hydraulic pressing device, the generated pressing force can be adjusted independently of this torque.

  When the ratio of the rotational speeds of the input rotary shaft 1 and the output gear 10 is changed, and when the deceleration is first performed between the input rotary shaft 1 and the output gear 10, the trunnions 15 and 15 are shown in FIG. As shown in FIG. 4, the peripheral surfaces 14, 14 of the power rollers 13, 13 are swung to the positions shown in FIG. 4, and the input side inner surfaces 3, 3 of the input side disks 2a, 2b The two output side disks 11 and 11 are brought into contact with the outer peripheral portions of the output side inner surfaces 12 and 12 respectively. On the contrary, when the speed is increased, the trunnions 15 and 15 are swung in the direction opposite to that shown in FIG. 4, and the peripheral surfaces 14 and 14 of the power rollers 13 and 13 are changed to the state shown in FIG. Conversely, the outer peripheral portions of the input side inner surfaces 3 and 3 of the two input side disks 2a and 2b and the central portions of the output side inner surfaces 12 and 12 of the two output side disks 11 and 11 are in contact respectively. Let An intermediate speed ratio (transmission ratio) can be obtained between the input rotary shaft 1 and the output gear 10 by setting the swing angles of the trunnions 15 and 15 to an intermediate position.

  In order to ensure the transmission efficiency and durability of the toroidal-type continuously variable transmission constructed and operated as described above, the peripheral surfaces 14, 14 of the power rollers 13, 13 and the input side disks 2a, 2b It is necessary to prevent excessive slippage from occurring at the rolling contact portion (traction portion) between the input side inner surfaces 3 and 3 and the output side inner surfaces 12 and 12 of the output side disks 11 and 11. That is, each rolling contact portion has a contact ellipse, as is widely known in the technical field of toroidal-type continuously variable transmissions. The major axis direction of the contact ellipse is determined by the two input side disks 2a, 2b. And it changes with the rotation of both the output side disks 11, 11 (contact ellipse spins). However, if such slippage exceeding the spin, which is an unavoidable slip, occurs at each rolling contact portion, the transmission efficiency deteriorates.

  In particular, when significant slip called gloss slip occurs at each rolling contact portion, each of the peripheral surfaces 14 and 14 and the input side inner side surfaces 3 and 3 or the output side inner side surfaces 12 and 12 are lubricated. A metal contact that abuts without passing through the (traction oil) film is generated. When metal contact occurs, damage to the peripheral surfaces 14 and 14 and the input-side inner side surfaces 3 and 3 or the output-side inner side surfaces 12 and 12 proceeds, and the durability of the toroidal continuously variable transmission is increased. Not only is damaged, but if it is remarkable, it may cause a serious failure such as seizure. The swing angles of all the trunnions 15 and 15 are synchronized with each other hydraulically and mechanically, but the possibility of failure cannot be denied by the hydraulic synchronization. Moreover, it is difficult to synchronize completely in any of the hydraulic type and the mechanical type. For each of the power rollers 13, 13, the peripheral surfaces 14, 14, the input side inner surfaces 3, 3, and the output side There is no denying the possibility that a slight deviation will occur at the contact position with the side surfaces 12 and 12 (with respect to the radial direction of the inner side surfaces 3 and 12).

  Conventionally, a structure described in Patent Document 4 is known as a technique for detecting slippage in a power transmission unit of a continuously variable transmission. In the case of the structure described in Patent Document 4, the belt type continuously variable transmission is intended to detect slippage of the contact portion between the pulley and the belt. For this reason, the input rotation speed and the output rotation speed are compared via a gear ratio, and it is determined that slipping has occurred when a difference exceeding a threshold value occurs. Detecting slipping in this manner is effective in the case of a belt type continuously variable transmission, but cannot be applied in the case of a toroidal type continuously variable transmission. This is because, in the case of a belt-type continuously variable transmission, the power transmission path is one system (only one belt), whereas in the case of a toroidal continuously variable transmission, power transmission is performed. This is because there are multiple routes. For example, in the case of the structure described in FIGS. 3 to 5, four power rollers 13 and 13 are arranged in parallel with each other in the power transmission direction. Therefore, even if an excessive slip occurs in the traction portion of one of the power rollers 13, if the other three power rollers 13 and 13 are transmitting power properly, the both input side disks The ratio between the rotational speeds 2a and 2b and the rotational speeds of the output disks 11 and 11 is an appropriate value corresponding to the gear ratio. For this reason, the excessive slip in the traction part of the said one power roller 13 cannot be detected.

  In addition, it is assumed that excessive slip at the traction portion of one power roller 13 affects the ratio between the rotational speeds of the input disks 2a and 2b and the rotational speeds of the output disks 11 and 11. However, the slip cannot be detected with sufficient accuracy. In particular, when the operating speed of the toroidal type continuously variable transmission is low, it is very difficult to detect the slip. Moreover, even if the slip, which is a microscopic phenomenon occurring in the traction section, is detected by a shift in the gear ratio, which is a macro phenomenon, it takes a considerable amount of time from the occurrence of the slip until the slip is detected. It is inevitable that a delay will occur, and it is difficult to prevent this slip from growing to a gross slip.

JP 7-20569 A JP 11-63146 A Japanese Patent Laid-Open No. 11-166605 JP 2005-42884 A

  In the present invention, in view of the circumstances as described above, excessive {slip based on power transmission (Creep)} slip occurs in any of a plurality of power rollers constituting a toroidal continuously variable transmission. In this case, the present invention has been invented to realize a structure that can detect this slip quickly (with high accuracy).

The toroidal type continuously variable transmission of the present invention, like the conventionally known toroidal type continuously variable transmission, has at least one pair of input side disk and output side disk, a plurality of support members, and a plurality of A power roller and a pressing device are provided.
Of these, the input-side disk and the output-side disk are supported concentrically and freely in relative rotation with each axial side surface being a toroidal curved surface facing each other.
Further, the support members are freely provided at a position between the two disks in the axial direction so as to be oscillated and displaced around a pivot that is twisted with respect to the central axes of the two disks.
Each power roller is rotatably supported by each support member, and has a spherical convex surface that is in contact with one axial side surface of both disks.
Further, the pressing device presses both the discs in a direction approaching each other.

In particular, the toroidal-type continuously variable transmission according to the present invention includes state quantity measuring means and comparison means.
Of these, the state quantity measuring means measures at least one of the inclination angle of each of the support members around the pivots and the rotational speed of the power rollers.
The comparing means compares the state quantity with at least one of the inclination angle for each support member and the rotational speed for each power roller measured by the state quantity measuring means.
Then, the comparison means is configured such that the tilt angle of any one of the support members is different from the tilt angle of the other support member beyond a threshold value, or the rotational speed of any of the power rollers is different from the rotational speed of the other power roller. When the difference exceeds the threshold value, excessive slippage occurs at the contact portion between the peripheral surface of one of the power rollers and one side surface in the axial direction of the input side disk and output side disk holding the power roller. It has the function to judge.
Further, when the present invention is implemented, as described in claim 2, for example, the pressing device is a hydraulic device that generates a pressing force in a direction in which both disks are brought close to each other by introducing hydraulic pressure into the hydraulic chamber. And And when the said comparison means determines that the excessive slip has generate | occur | produced, the pressing force which the said press apparatus generate | occur | produces is enlarged.

  According to the toroidal-type continuously variable transmission of the present invention configured as described above, when an excessively large slip (exceeding slip based on power transmission (Creep)) occurs in any of a plurality of power rollers. This slip can be detected quickly (accurately). Then, the pressing force generated by the pressing device is immediately increased to eliminate the excessive slip, and it is possible to reliably prevent the slip from growing to a gross slip. For this reason, the transmission efficiency and durability of the toroidal-type continuously variable transmission can be sufficiently secured.

  An example of the embodiment of the present invention will be described with reference to FIGS. The feature of this example is that the double cavity type toroidal continuously variable transmission shown in FIG. 1 is composed of two front left and right (FL, FR), two rear left and right (RL, RR). ), The inclination angles (tilt angles) of the trunnions 15 and 15 that support the four power rollers 13 and 13 in a freely rotatable manner around the pivots 21 and 21 (see FIGS. 4 to 5). By measuring every 15 and 15, it is in the point which detects this when the excessive slip generate | occur | produces in the traction part regarding the power roller 13 of any one of said power rollers 13 and 13. The basic structure and operation of the toroidal-type continuously variable transmission are the same as those of the conventional toroidal-type continuously variable transmission such as the structures shown in FIGS. Illustration and description are omitted.

  In the case of this example, by providing an encoder between the pivots 21 and 21 provided at the ends of the trunnions 15 and 15 and the non-rotating portion that supports the pivots 21 and 21, The inclination angle of each trunnion 15, 15 is measured. As shown in FIG. 2, the inclination angles of the trunnions 15 and 15 are continuously measured during operation of the toroidal continuously variable transmission, and a signal representing the measured value is input to a comparison circuit of a controller (not shown). . In FIG. 2, for the sake of clarity, the inclination angles of the trunnions 15 and 15 are illustrated as being different from each other. However, in the actual case, the traction relating to the power rollers 13 and 13 is described. As long as excessive slip does not occur in the portion, the inclination angles of the trunnions 15, 15 coincide with each other (the left half portions of the lines in FIG. 2 overlap each other).

  The comparison circuit, to which a signal representing the tilt angle of each trunnion 15, 15 is input, constantly compares the tilt angle of each trunnion 15, 15. Then, a difference exceeding a preset threshold value (for example, 0.5 degrees) is generated between the inclination angle of one (at least one) trunnion 15 and the inclination angle of the other trunnions 15 and 15. In this case, it is determined that excessive slip has occurred in the traction portion of the power roller 13 supported by any trunnion 15. For example, as shown in FIG. 2, the inclination angle of the trunnion 15 that supports the rear right (RR) power roller 13 is equal to that of the trunnions 15 and 15 that support the other (FL, FR, RL) power rollers 13 and 13. If it begins to differ from the inclination angle, it is determined that the slip of the traction portion of the rear side right (RR) power roller 13 has started to increase. Then, the hydraulic pressure introduced into the hydraulic chamber of the hydraulic pressing device is increased, and the pressing force generated by the pressing device is immediately increased. In this way, if the surface pressure of the traction portion related to each of the power rollers 13 and 13 is increased, the excessive slip can be eliminated and the slip can be reliably prevented from growing to a gross slip. For this reason, the transmission efficiency and durability of the toroidal-type continuously variable transmission can be sufficiently secured. In the case of carrying out the present invention, it is only necessary to detect that excessive slip has occurred in any part, and it is not particularly necessary to identify the power roller 13 that has generated excessive slip.

In the above description, an excessive slip is detected by the difference in the inclination angle of each trunnion, but this slip can also be detected by a difference in the rotation speed of each power roller.
Further, the present invention is not limited to the double cavity type toroidal continuously variable transmission in which two input side disks and two output side disks are provided as shown in the figure, for example, as described in Patent Document 1. The present invention can also be implemented by a single cavity type toroidal continuously variable transmission in which one input disk and one output disk are provided. When implemented with a single-cavity toroidal continuously variable transmission, the difference between the rotational speeds of a pair of power rollers or the inclination angle of a trunnion that supports both power rollers exceeds a threshold. When this occurs, it is determined that an excessive slip has occurred in at least one of the traction portions related to the power roller.
Furthermore, the present invention can be implemented not only in a double cavity type and a single cavity type, but also in a full toroidal toroidal continuously variable transmission as well as a half toroidal continuously variable transmission.

The schematic diagram of the toroidal type continuously variable transmission for demonstrating this invention. The diagram which shows the relationship between the inclination-angle of each trunnion and elapsed time. Sectional drawing which shows one example of the toroidal type continuously variable transmission used as the object of this invention. AA sectional drawing of FIG. BB sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input rotating shaft 2a, 2b Input side disk 3 Input side inner surface 4 Ball spline 5 Casing 6 Partition part 7 Through-hole 8 Output cylinder 9 Rolling bearing 10 Output gear 11 Output side disk 12 Output side inner surface 13 Power roller 14 Circumferential surface DESCRIPTION OF SYMBOLS 15 Trunnion 16 Support shaft 17 Radial needle bearing 18 Thrust ball bearing 19 Thrust needle bearing 20 Radial needle bearing 21 Pivot 22 Actuator 23 Drive shaft 24 Pressing device

Claims (2)

  At least one pair of an input side disk and an output side disk that are supported concentrically and freely rotating relative to each other in a state in which one side surfaces in the axial direction, each of which is a toroidal curved surface, are opposed to each other in the axial direction. A plurality of support members provided in a position between the two discs so as to be freely oscillating around a pivot that is twisted with respect to the central axes of the two discs, and each of the support members can be freely rotated. A toroidal stepless unit comprising a power roller that is supported and has a spherical convex surface that is in contact with one axial side surface of both disks, and a pressing device that presses both disks toward each other. In the transmission, a state quantity measuring means for measuring at least one of an inclination angle of each of the support members around the pivots and a rotation speed of the power rollers; Comparing means for comparing state quantities of at least one of the inclination angle for each of the support members and the rotational speed for each of the power rollers measured by the state quantity measuring means. When the inclination angle of one of the support members is different from the inclination angle of the other support member over a threshold value, or when the rotation speed of any of the power rollers is different from the rotation speed of the other power roller beyond the threshold value, It has a function of determining that excessive slip has occurred at the contact portion between the peripheral surface of any power roller and one side surface in the axial direction of the input side disk and output side disk holding the power roller. A toroidal-type continuously variable transmission.   When the pressing device is of a hydraulic type that generates a pressing force in a direction in which both disks are brought close to each other by introducing hydraulic pressure into the hydraulic chamber, and the comparison means determines that excessive slip has occurred, The toroidal continuously variable transmission according to claim 1, wherein the pressing force generated by the pressing device is increased.

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