JP2012122605A - Toroidal continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toroidal continuously variable transmission which prevents hunting or settles the hunting in an early stage when starting a prime mover.SOLUTION: A trunnion 15 is tilted to change the speed change ratio of an input side disk to an output side disk by displacing the trunnion 15 along the axial direction of a pivot 14 from the neutral position at which the trunnion 15 is not tilted by a driving device 32. There are provided coned disk springs 38, 39 keeping a state in which the position of the trunnion 15 along the axial direction of the pivot 14 is substantially matched with the neutral position where the trunnion 15 is not tilted when the driving device 32 is in a non-operational state. Thus, during the time in which the hydraulic pressure in a hydraulic pressure chamber is not sufficiently increased, the reciprocating motion of the driving device can be stopped, and consequently the hunting can be prevented or can be settled in an early stage when starting a prime mover. In other words, when the hydraulic pressure in the hydraulic pressure chamber is low, the reciprocating motion of the driving device is fixed, and when the hydraulic pressure is increased, the operation of the driving device similar to that of the conventional one can be achieved.

Description

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

  For example, a double-cavity toroidal continuously variable transmission used as a transmission for an automobile is configured as shown in FIGS. As shown in FIG. 5, an input shaft (center shaft) 1 is rotatably supported inside the casing 50, and two input side disks 2, 2 and two outputs are provided on the outer periphery of the input shaft 1. Side disks 3 and 3 are attached. An output gear 4 is rotatably supported on the outer periphery of the intermediate portion of the input shaft 1. Output side disks 3 and 3 are connected to cylindrical flange portions 4a and 4a provided at the center of the output gear 4 by spline coupling.

  The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between an input side disk 2 and a cam plate 7 located on the left side in the drawing. . The output gear 4 is supported in the casing 50 via a partition wall 13 formed by coupling two members, so that the output gear 4 can rotate around the axis O of the input shaft 1 while the axis O. Directional displacement is prevented.

  The output side disks 3 and 3 are supported by needle bearings 5 and 5 interposed between the input shaft 1 so as to be rotatable about the axis O of the input shaft 1. Further, the left input side disk 2 in the figure is supported on the input shaft 1 via a ball spline 6, and the right side input disk 2 in the figure is splined to the input shaft 1. Rotates with the input shaft 1. A power roller 11 (see FIG. 7) is rotatable between the inner side surfaces (concave surfaces) 2a, 2a of the input side disks 2, 2 and the inner side surfaces (concave surfaces) 3a, 3a of the output side disks 3, 3. Is sandwiched between.

  A step 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 6, and the step 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step 2b. At the same time, the back surface (the right surface in FIG. 6) of the input side disk 2 is abutted against the loading nut 9. Thereby, the displacement of the input side disk 2 in the direction of the axis O with respect to the input shaft 1 is substantially prevented. Further, a disc spring 8 is provided between the cam plate 7 and the flange 1d of the input shaft 1, and this disc spring 8 is a concave surface 2a, 2a, 3a of each disk 2, 2, 3, 3. , 3a and the contact surface between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 are applied with a pressing force.

  FIG. 7 is a cross-sectional view taken along the line AA of FIG. As shown in FIG. 7, a pair of trunnions 15, 15 that swing about a pair of pivots 14, 14 that are twisted with respect to the input shaft 1 are provided inside the casing 50. In addition, illustration of the input shaft 1 is abbreviate | omitted in FIG. Each trunnion 15, 15 is a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 7) of the support plate portion 16 so as to be bent toward the inner surface side of the support plate portion 16. have. The bent wall portions 20 and 20 form concave pocket portions P for accommodating the power rollers 11 in the trunnions 15 and 15. Further, the pivot shafts 14 and 14 are concentrically provided on the outer side surfaces of the bent wall portions 20 and 20, respectively.

  A circular hole 21 is formed in the center portion of the support plate portion 16, and a base end portion (first shaft portion) 23 a of the displacement shaft 23 is supported in the circular hole 21. Then, by swinging each trunnion 15, 15 about each pivot 14, 14, the inclination angle of the displacement shaft 23 supported at the center of each trunnion 15, 15 can be adjusted. In addition, each power roller 11 is rotatably supported around the tip end portion (second shaft portion) 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15. 11 is sandwiched between the input disks 2 and 2 and the output disks 3 and 3. In addition, the base end part 23a and the front-end | tip part 23b of each displacement shaft 23 and 23 are mutually eccentric.

  Further, the pivot shafts 14, 14 of the trunnions 15, 15 are supported so as to be swingable with respect to the pair of yokes 23A, 23B and displaceable in the axial direction (vertical direction in FIG. 7). The horizontal movement of the trunnions 15 and 15 is restricted by 23B. Each yoke 23A, 23B is formed in a rectangular shape by pressing or forging a metal such as steel. Four circular support holes 18 are provided at the four corners of each of the yokes 23 </ b> A and 23 </ b> B, and the pivot shafts 14 provided at both ends of the trunnion 15 swing through the radial needle bearings 30. It is supported freely. In addition, a circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (the left-right direction in FIG. 7). 64 and 68 are fitted inside. That is, the upper yoke 23A is swingably supported by the spherical post 64 supported by the casing 50 via the fixing member 52, and the lower yoke 23B is supported by the spherical post 68 and the drive for supporting the same. The upper cylinder body 61 of the cylinder 31 is swingably supported.

  The displacement shafts 23 and 23 provided in the trunnions 15 and 15 are provided at positions 180 degrees opposite to the input shaft 1. In addition, the direction in which the distal end portion 23b of each of the displacement shafts 23 and 23 is eccentric with respect to the base end portion 23a is the same direction as the rotational direction of both the disks 2, 2, 3 and 3 (in FIG. (Reverse direction). Further, the eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 1 is disposed. Accordingly, the power rollers 11 and 11 are supported so that they can be slightly displaced in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component member based on the thrust load generated by the pressing device 12, each component This displacement is absorbed without applying an excessive force to the member.

  Further, between the outer surface of the power roller 11 and the inner surface of the support plate portion 16 of the trunnion 15, a thrust ball bearing (thrust bearing) 24 that is a thrust rolling bearing is sequentially formed from the outer surface side of the power roller 11. A thrust needle bearing 25 is provided. Among these, the thrust ball bearing 24 supports the rotation of each power roller 11 while supporting the load in the thrust direction applied to each power roller 11. Each of such thrust ball bearings 24 includes a plurality of balls (hereinafter referred to as rolling elements) 26, 26, an annular retainer 27 that holds the rolling elements 26, 26 in a freely rolling manner, And an annular outer ring 28. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface (large end surface) of each power roller 11, and the outer ring raceway is formed on the inner side surface of each outer ring 28.

  The thrust needle bearing 25 is sandwiched between the inner surface of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. Such a thrust needle bearing 25 supports the thrust load applied to each outer ring 28 from the power roller 11, while the power roller 11 and the outer ring 28 swing around the base end portion 23 a of each displacement shaft 23. Allow.

  Further, driving rods (trunnion shafts) 29 and 29 are provided at one end portions (lower end portions in FIG. 7) of the trunnions 15 and 15, respectively, and a driving piston ( Hydraulic pistons) 33, 33 are fixed. Each of these drive pistons 33 and 33 is oil-tightly fitted in a drive cylinder 31 constituted by an upper cylinder body 61 and a lower cylinder body 62. The drive pistons 33 and 33 and the drive cylinder 31 constitute a drive device 32 that displaces the trunnions 15 and 15 in the axial direction of the pivots 14 and 14 of the trunnions 15 and 15.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input side disks 2 and 2 via the pressing device 12. Then, the rotation of the input side disks 2 and 2 is transmitted to the output side disks 3 and 3 via the pair of power rollers 11 and 11, and the rotation of the output side disks 3 and 3 is further transmitted to the output gear 4. It is taken out more.

  When changing the rotational speed ratio between the input shaft 1 and the output gear 4, the pair of drive pistons 33, 33 are displaced in opposite directions. As the drive pistons 33 and 33 are displaced, the pair of trunnions 15 and 15 are displaced in directions opposite to each other. For example, the power roller 11 on the left side of FIG. 7 is displaced downward in the figure, and the power roller 11 on the right side of FIG. 7 is displaced upward in the figure. As a result, the peripheral surfaces 11a and 11a of the power rollers 11 and 11 act on contact portions of the input side disks 2 and 2 and the inner side surfaces 2a, 2a, 3a and 3a of the output side disks 3 and 3, respectively. The direction of the tangential force changes. As the force changes, the trunnions 15 and 15 swing (tilt) in opposite directions around the pivots 14 and 14 pivotally supported by the yokes 23A and 23B.

  As a result, the contact position between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 3a changes, and the gear ratio between the input shaft 1 and the output gear 4 changes. Further, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11 and 11 and the outer rings attached to the power rollers 11 and 11 will be described. 28 and 28 slightly rotate around the base end portions 23a and 23a of the displacement shafts 23 and 23, respectively. Since the thrust needle bearings 25 and 25 exist between the outer side surfaces of the outer rings 28 and 28 and the inner side surfaces of the support plate portions 16 constituting the trunnions 15 and 15, respectively, the rotation is performed smoothly. Is called. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 23, 23 can be small.

  As described above, pressure oil is supplied to the drive cylinder 31 of the drive device 32 when the drive piston 33 of the drive device 32 is displaced by hydraulic pressure to change the gear ratio between the input shaft 1 and the output gear 4. In the control of the displacement, the movement of the trunnion 15 (the axial displacement of the pivot axis and the swing displacement (displacement of the tilt angle) about the pivot axis) is fed back via a mechanical feedback mechanism including a princess cam, for example. It is done by that. In other words, after the control valve is opened and the driving device 32 is operated, when the amount of displacement of the trunnion 15 in the axial direction or the amount of displacement in the swing direction (tilt angle) becomes the target amount of displacement by the feedback mechanism, The valve is closed to stop the supply and discharge of the pressure oil to the drive pistons 33 and 33.

  The trunnion 15 maintains the current tilt angle without tilting when the input side disk 2 and the output side disk 3 are positioned at a predetermined neutral position, and tilts when displaced from the neutral position. . That is, the tilt angle is changed. The grounding position of the power rollers 11, 11 through the oil film to the input side disk 2 and the output side disk 3 changes depending on the tilt angle of the trunnion 15, and the gear ratio changes. Therefore, the gear ratio is determined by the tilt angle of the trunnion 15. Further, if the displacement amount (offset amount) from the neutral position along the axial direction of the pivot axis of the trunnion 15 (hereinafter sometimes referred to as the pivot direction) is large, the tilt speed of the trunnion is increased, and the unit of the gear ratio The rate of change per hour (speed of change in gear ratio) becomes faster. That is, the offset amount corresponds to the speed of change of the speed ratio as a differential value of the speed ratio.

In such a mechanical feedback mechanism, there is a possibility that the transmission gear ratio may deviate from the desired transmission gear ratio due to the assembly gap of each component member, elastic deformation, etc., and the transmission gear ratio changes based on fluctuations in input torque. (For example, refer to Patent Document 1).
On the other hand, an electric type equipped with a sensor that detects the amount of displacement of the trunnion 15 in the axial direction and the swinging direction and outputs an electric signal, and a control device that controls the control valve based on the electric signal from the sensor. Control using a feedback mechanism is also performed. In this case, it is possible to prevent a shift or change in the gear ratio as in the case of the mechanical type described above.

  However, in order to detect the displacement of the trunnion 15 in the axial direction and the swinging direction, two types of sensors, a linear motion detection sensor and a rotation detection sensor, are required. For this reason, by arranging these two types of sensors, there is a possibility that the degree of freedom of arrangement of other components is reduced, the reliability is lowered, and the cost is increased. Further, depending on the arrangement state of the two types of sensors, there is a possibility that an unnecessary shift is performed. Furthermore, the two types of sensors are required to have a performance capable of withstanding vibration and high temperature, which causes an increase in cost.

  Therefore, in Patent Document 1, the rotational speeds of the input side disk 2 and the output side disk 3 are not detected by detecting the displacement of the trunnion 15 in the axial direction and the swinging direction and feeding back the detected displacement. Is detected by a rotation detection sensor, and a gear ratio is obtained based on the rotational speed ratio between the rotational speed of the input side disk 2 and the rotational speed of the output side disk, and the speed change ratio (differential value of the speed ratio) ), The movement of the trunnion 15 is estimated from the calculated differential value of the transmission ratio, and the above-described control valve is controlled. As described above, the tilt angle of the trunnion 15 corresponds to the transmission ratio, and the offset amount along the pivot axis direction of the trunnion 15 corresponds to the differential value of the transmission ratio. As a substitute characteristic of the offset amount, the drive device 32 can be feedback-controlled.

  In this case, since the complicated movement of the trunnion 15 is not detected but only the rotational speeds of the input side disk 2 and the output side disk 3 that merely rotate are measured, the machine that feeds back the movement of the trunnion 15 In addition to solving the problems of the type feedback mechanism and the electric type feedback mechanism, it is possible to reduce the cost of the control device that controls the drive device 32 to control the gear ratio.

  Further, in the toroidal type continuously variable transmission, there has been proposed one in which a disc spring is incorporated on one side of the inside of the driving cylinder 31 of the driving device 32 partitioned by the driving piston 33 and the driving piston 33 is biased to the Low side. (For example, refer to Patent Document 2). This prevents the gear ratio from changing to High when the vehicle is driven by repulsion after the engine is stopped or when the vehicle is pulled and moved. If the trunnion 15 connected to the drive piston 33 is offset to the High side when the engine is stopped, the gear ratio is returned to the Low side after the engine operation starts and then returned to the Low side. The gear ratio does not change smoothly but changes abruptly. Therefore, the trunnion 15 is urged to the Low side by the disc spring when the engine is stopped, so that the gear ratio becomes the Low side when the engine is started, and the structure starts smoothly from the Low side at the next start. is there.

JP 2003-269598 A JP 2000-9197 A

By the way, as described in Patent Document 1, when controlling the drive device 32 that moves the trunnion 15 along the axial direction from the gear ratio and its differential value, as shown in Patent Document 2, the disc spring is used. If the configuration is such that the drive piston 33 is energized, the following problems occur when the engine is started.
That is, when the engine is started, the trunnion 15 is displaced from the neutral position (offset state) so as to be on the low side along the axial direction (pivotal direction) by the biasing force of the disc spring. In this state, the offset amount of the trunnion 15 (the amount of change from the neutral position) is such that the drive piston 33 is on the opposite side of the disc spring of the drive cylinder 31 by the disc spring in a state where the hydraulic pressure is not applied to the drive device 32. It is a big thing because it is in a state of being abutted against the inner surface.

  Since the differential value of the gear ratio is obtained from the rotational speeds of the input side disk 2 and the output side disk 3 and the drive device 32 is controlled, the input side disk 2 and the output side disk 3 are not rotated. The offset amount of the trunnion 15 cannot be controlled. Therefore, when the toroidal-type continuously variable transmission is mounted on the vehicle, the transmission is stopped from the stopped state (that is, when the transmission is in the P (parking) position or the N (neutral) position). At the moment when the input side disk 2 and the output side disk 3 start to rotate by selecting the transmission (D (drive) position), the toroidal continuously variable transmission or the toroidal type corresponding to the offset amount of the trunnion 15 described above The transmission including the continuously variable transmission will shift greatly.

  If the rotational speeds of the input side disk 2 and the output side disk 3 at this time are large, the trunnion 15 has a large offset amount and the swinging force (tilting force) or swinging speed (tilting speed) of the trunnion 15 is large. ) Is large, and there is a risk that the trunnion 15 will hit the tilt stopper that restricts the limit of the tilt angle of the trunnion 15, and there is a risk that it will be costly to provide a structure for preventing this.

Such a problem does not pose a problem when a mechanical or electrical feedback mechanism that detects the position of the trunnion 15 is used.
In the case where such a feedback mechanism is used, even if the axial position of the trunnion 15 by the above-described disc spring is largely offset with respect to the neutral position in a state where the hydraulic pressure is not applied to the driving device 32, When the actual tilt angle of the trunnion 15 substantially matches the target tilt angle, if the hydraulic pressure is applied, the offset amount of the trunnion 15 is immediately controlled, and the trunnion 15 is returned to the neutral position. Such a problem does not occur.

  In other words, when the trunnion 15 is offset from the neutral position to the Low side so that the trunnion 15 tilts to the Low side at the time of departure, it is controlled to the Low side by the shift control when the vehicle enters the running state, but the hydraulic pressure is applied The trunnion 15 starts to tilt toward the low side based on the offset amount of the trunnion by the disc spring in a state where the trunnion is not, and the trunnion offset amount and the tilt angle of the trunnion 15 are fed back. At this time, if the tilt angle increases to the Low side based on the large amount of the trunnion offset, the target trunnion approaches the Low tilt angle of the trunnion, and the axial position of the trunnion 15 is set to the neutral side. The control to return to is immediately started, and the trunnion 15 is prevented from being largely tilted at a high rotational speed and hitting the stopper.

Further, when the tilt angle of the trunnion 15 based on the offset amount by the disc spring and the target tilt angle based on the gear ratio control are significantly different, the hydraulic pressure is transferred to the driving device 32 from the stop state to the traveling state. When applied, the offset amount of the trunnion 15 is adjusted so that the desired tilt angle is immediately obtained, and a situation where the trunnion 15 hits the stopper is prevented.
That is, since the position of the trunnion 15 is detected and feedback control is performed, the position of the trunnion 15 is obtained regardless of whether or not the hydraulic pressure is applied to the driving device 32, and the travel state is reached. Based on the position, control of the drive device 32 is started. At this time, since the offset amount of the trunnion 15 is controlled immediately, the trunnion 15 is not greatly tilted at a high speed based on the offset amount in the stopped state.
Therefore, the above problems are not caused by mechanical or electrical detection and feedback control of the trunnion 15 in the axial direction or swinging position, but in the actual axial position or swinging position of the trunnion 15. This is caused when the differential value is calculated from the gear ratio between the input side disk 2 and the output side disk 3 without detecting this, and the gear ratio is controlled based on this differential value.

  However, when the movement of the trunnion 15 is detected mechanically or electrically and feedback control is performed, there are the above-mentioned problems, and compared with the case where the gear ratio is controlled using the differential value of the gear ratio. There is a problem that the cost becomes high.

  Another problem is that the hydraulic pressure rises slowly in the transmission when the engine is started (for example, when starting from idle stop). That is, if the hydraulic pressure in the hydraulic cylinder (speed increasing hydraulic pressure chamber, deceleration hydraulic pressure chamber) in the driving cylinder 31 of the driving device 32 that supports the power roller 11 (trunnion 15) does not rise (does not act), the power roller There is a possibility that the center of 11 is offset from the center of the disks 2 and 3 and hunting occurs.

  The present invention has been made in view of the above circumstances, and calculates a differential value of the gear ratio between the input side disk and the output side disk, and substitutes the differential value for the offset amount from the neutral position in the axial direction of the trunnion. When controlling the gear ratio as a characteristic, holding the trunnion in the neutral position during the stop state prevents the trunnion from tilting significantly when the stop state is activated. An object is to provide a step transmission.

  Another object of the present invention is to provide a toroidal continuously variable transmission that can prevent hunting at the time of starting a prime mover or can quickly collect hunting.

In order to achieve the above object, the toroidal continuously variable transmission according to claim 1 is characterized in that an input side disk and an output that are supported concentrically and rotatably with their respective inner surfaces facing each other. A side disk, a power roller sandwiched between the input side disk and the output side disk, and a twisted position with respect to the central axis of the input side disk and the output side disk and provided concentrically with each other A plurality of trunnions that move along the axial direction of the pair of pivots and tilt about the pivot axis and rotatably support the power rollers, and the trunnions along the axial direction of the pivot axes. A toroidal-type continuously variable transmission comprising a drive device that is displaced by
When the drive device is in a non-operating state, neutral position holding means is provided that holds the position of the trunnion along the axial direction of the pivot in a state that substantially matches the neutral position where the trunnion does not tilt. To do.

  In the first aspect of the present invention, when the drive device is in the non-operating state, the neutral position holding means that holds the position along the axial direction of the pivot axis of the trunnion in a state substantially coincident with the neutral position where the trunnion does not tilt. Therefore, when the hydraulic pressure in the hydraulic chamber is not sufficiently increased, the reciprocating motion of the driving device can be stopped, thereby preventing hunting at the time of starting the prime mover or early convergence of hunting. In other words, when the hydraulic pressure in the hydraulic chamber is low, the reciprocating motion of the drive device is fixed, and when the hydraulic pressure increases, the drive device moves in the same manner as in the past.

3. The toroidal continuously variable transmission according to claim 2, wherein the input side disc and the output side disc are supported concentrically and rotatably with the inner side surfaces thereof facing each other, and the input side disc. Axial direction of a pair of pivots provided concentrically with each other at a twisted position with respect to a central axis of the input side disk and the output side disk, and a power roller sandwiched between the output side disk and the output side disk A plurality of trunnions that move along the axis and tilt around the pivot axis and rotatably support the power rollers, and a drive device that displaces the trunnions along the axial direction of the pivot axis. ,
When the gear ratio is controlled by displacing the trunnion from the neutral position where the trunnion does not tilt by the driving device along the axial direction of the pivot, the rotational speed of the input side disk and the output side disk is determined. In the toroidal type continuously variable transmission that uses the obtained differential value of the transmission ratio as a substitute characteristic of the amount of displacement along the axial direction of the pivot from the neutral position of the trunnion,
When the drive device is in a non-operating state, neutral position holding means is provided that holds the position of the trunnion along the axial direction of the pivot substantially in a state substantially coincident with the neutral position.

In the invention according to claim 2, when the speed ratio is controlled using the differential value of the speed ratio as described above, for example, at the time of starting from the stop state (stop state) to the operating state (running state), Since the position along the pivot axis direction of the trunnion is a neutral position by the neutral position holding means, the trunnion does not tilt, and the trunnion is adjusted when the trunnion offset amount is changed in order to control the gear ratio. The tilt will start.
That is, for example, the trunnion is not greatly tilted at a high speed as in the case where the offset amount of the trunnion in the stopped state is increased by being biased to the low side by the disc spring. Therefore, it is possible to prevent the trunnion from strongly hitting the stopper that regulates the range of the tilt angle of the trunnion.

The toroidal type continuously variable transmission according to claim 3 is the invention according to claim 1 or 2, wherein the drive device divides the drive cylinder and the inside of the drive cylinder into two hydraulic chambers, A drive piston that moves linearly based on the hydraulic pressure of these hydraulic chambers to displace the trunnion along the axial direction of the pivot,
The neutral position holding means is provided in each of the two hydraulic chambers, and includes biasing means for biasing the position of the drive piston so as to oppose each other toward the side where the trunnion is in the neutral position. It is characterized by that.

  In the invention according to claim 3, since the neutral position holding means is composed of biasing means provided in two hydraulic chambers separated by the drive piston of the drive cylinder of the drive device, the neutral position holding means is a toroidal type. The neutral position holding means can be provided in the toroidal type continuously variable transmission without interfering with other components of the continuously variable transmission and without making a major design change.

  According to a fourth aspect of the present invention, the toroidal continuously variable transmission according to the third aspect of the present invention is characterized in that the two urging means each include a piston for a hydraulic chamber provided movably in the two hydraulic chambers. The drive piston is urged through a via.

  In the invention described in claim 4, since the urging means pushes the drive piston through the hydraulic chamber piston, an accurate input torque can be calculated from the differential pressure if the hydraulic pressure increases.

  A toroidal continuously variable transmission according to a fifth aspect is the invention according to the third or fourth aspect, wherein the urging means includes an urging force adjusting means for adjusting the urging force.

In the invention according to claim 5, it becomes possible to hold the trunnion at a position closer to the neutral position.
Here, when the position of the trunnion driven by the drive piston is held at the neutral position by the two biasing means facing each other and biasing the drive piston, individual differences of the biasing means, biasing means, If the balance of the urging force by these urging means is lost due to the arrangement of these, etc., the drive piston may be displaced from the position where the trunnion is in the neutral position. However, since the urging force of the urging means can be adjusted by the urging force adjusting means, the trunnion is held at a position closer to the neutral position, and the trunnion is greatly inclined at a high speed when starting up. Can prevent rolling.

  The toroidal continuously variable transmission according to claim 6 is the invention according to claim 1 or 2, wherein the drive device divides the drive cylinder and the inside of the drive cylinder into two hydraulic chambers, A drive piston that moves linearly based on the hydraulic pressure of these hydraulic chambers to displace the trunnion along the axial direction of the pivot, an inner peripheral surface of a member on the drive cylinder side, and an outer peripheral surface of a member on the drive piston side The neutral position holding means moves the trunnion to the neutral position by the drive device immediately before the drive device is deactivated. A drive control means for causing the piston seal to slide when the member on the drive cylinder side and the member on the drive piston side slide through the piston seal. The friction force generated between the piston seal and the drive cylinder side member or the drive piston side member is made larger than the gravity acting on the total weight of all the members that are driven by the drive device and move together. It is characterized by.

  According to the sixth aspect of the present invention, the frictional force corresponding to the piston seal generated between the drive cylinder side member and the drive piston side member that slides with respect to the drive cylinder side member via the piston seal. However, it is larger than the gravity acting on the total weight of all the members that are driven by the driving device and move together. That is, since the frictional force (friction) generated by the piston seal is larger than the gravity acting on all members driven by the driving device including the trunnion and the power roller, for example, torque is applied to the toroidal continuously variable transmission. When the engine is stopped (ie, the drive device is inactive), all members driven by the drive device, including trunnions, power rollers, and drive pistons, are driven by gravity against the drive cylinder. It wo n’t fall off.

  Therefore, if the trunnion is controlled to return to the neutral position when the engine is stopped, the trunnion is held at the neutral position by the frictional force of the piston seal while the engine is stopped. Therefore, when the transmission ratio is controlled using the differential value of the transmission ratio, the trunnion is located in the neutral position by the piston seal at the time of starting from the stop state to the operating state. Without tilting, the trunnion starts tilting when the trunnion offset amount is changed in order to control the gear ratio. Thus, the trunnion does not tilt significantly at a high speed at the time of activation, and it is possible to prevent the trunnion from strongly hitting the stopper that regulates the range of the tilt angle of the trunnion.

  In addition, the piston seal can be made to have a strong frictional force by simply changing the piston seal to one having a strong frictional force and controlling the trunnion to return to the neutral position when stopped. Except for changing to a device, no design change is required, and the embodiment can be implemented very easily. Further, structurally, the present invention can be implemented only by changing the piston seal, so there is no addition of parts, and an increase in cost and weight for implementing the present invention can be suppressed.

  Further, when the hydraulic pressure in the hydraulic chamber is insufficiently increased, the reciprocating motion of the drive device can be stopped, and hunting can be prevented or hunting can be quickly converged when starting the prime mover. In other words, when the hydraulic pressure in the hydraulic chamber is low, the reciprocating motion of the drive device is fixed, and when the hydraulic pressure increases, the drive device moves in the same manner as in the past.

The control method of the toroidal type continuously variable transmission according to claim 7 is the control method of the toroidal type continuously variable transmission according to any one of claims 1 to 6,
When the rotational speed of both or one of the input side disk and the output side disk is less than a predetermined value, the drive device moves the trunnion along the axial direction of the pivot from a neutral position where the trunnion does not tilt. Shifting control for controlling a gear ratio by displacing is prohibited, and the drive device is controlled so that a position along the pivot direction of the trunnion is set to a substantially neutral position.

  In the seventh aspect of the invention, the output from the rotation sensor becomes unstable based on the low rotational speed of the input side disk and the output side disk when the operation of the machine including the toroidal continuously variable transmission is started. However, when the rotational speeds of the input and output disks are below the set value, the control based on the output of the rotation sensor is not performed and the trunnion position is controlled to the neutral position. Is kept constant and the gear ratio can be prevented from becoming unstable.

According to the toroidal type continuously variable transmission of the present invention, the reciprocating motion of the drive device can be stopped during a time when the hydraulic pressure in the hydraulic chamber is insufficiently increased, so that hunting is prevented during start-up or early convergence of hunting is achieved. be able to.
Further, according to the toroidal type continuously variable transmission of the present invention, when the transmission ratio of the toroidal type continuously variable transmission is controlled based on the differential value of the transmission ratio obtained from the rotational speeds of the input side disk and the output side disk. It is possible to prevent the trunnion from tilting too much when the machine including the toroidal type continuously variable transmission is started.

It is principal part sectional drawing which shows the toroidal type continuously variable transmission of 1st Embodiment of this invention. It is principal part sectional drawing which shows the toroidal type continuously variable transmission of 2nd Embodiment of this invention. It is principal part sectional drawing which shows the toroidal type continuously variable transmission of 3rd Embodiment of this invention. It is a flowchart for demonstrating the control method of the toroidal type continuously variable transmission of 4th Embodiment of this invention. It is principal part sectional drawing which shows the toroidal type continuously variable transmission of 5th Embodiment of this invention. It is sectional drawing which shows an example of the specific structure of the half toroidal type continuously variable transmission conventionally known. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which shows a nozzle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The feature of the present invention lies in the structure of the neutral position holding means arranged in the driving device 32, and the other configurations and operations are the same as the conventional configurations and operations described above. Only the characteristic part will be referred to, and the other parts will be simply described with the same reference numerals as those in FIGS.
In the control of the transmission ratio of the toroidal continuously variable transmission according to the present invention, the transmission ratio is obtained by measuring the rotational speeds of the input side disk 2 and the output side disk 3 shown in FIGS. 6 and 7, respectively. A differential value of the transmission ratio is obtained, and the obtained differential value is used as a substitute characteristic of the offset amount of the trunnion 15. That is, in the toroidal transmission of the present invention, the transmission ratio is controlled by a known control method in which the differential value of the transmission ratio is used as a substitute characteristic of the offset amount of the trunnion 15.

FIG. 1 is a diagram showing a first embodiment of the present invention.
As shown in FIG. 1, in the driving device 32 of this example, as in the conventional example, the driving rod 29 is provided on the pivot 14 at one end of each trunnion 15 along the pivot direction. A drive piston 33 is fixed to the outer peripheral surface of the intermediate portion of the rod 29 by a nut 29A. Each of these drive pistons 33 is oil-tightly fitted into a drive cylinder 31 constituted by an upper cylinder body 61 and a lower cylinder body 62.
The drive piston 33 includes a cylindrical portion 34 that is fixed to the outer peripheral surface of the drive rod 29 and a piston main body 35 that extends in a disc shape from the substantially upper and lower central portions of the cylindrical portion 34 to the periphery.

  The inner space of the drive cylinder 31 is a columnar space through which a cylindrical portion 34 that is fixed to the outer peripheral surface of the drive piston 33 and the drive piston 33 penetrates the central portion, and upper and lower central portions of the columnar space. However, it is a cylinder space that spreads out in a disk shape around it, and the above-described piston main body 35 is disposed in this cylinder space. A cylinder space that is an internal space of the drive cylinder 31 is partitioned into upper and lower disk-like hydraulic chambers 36 and 37 by a piston body 35. In the hydraulic chambers 36 and 37, disc springs 38 and 39 for urging the piston main body 35 are provided, respectively.

A disc spring 38 disposed in the upper hydraulic chamber 36 biases the piston body 35 downward, and a disc spring 39 disposed in the lower hydraulic chamber 37 biases the piston body 35 upward. is doing.
The disc spring 38 has a disc shape in which a hole through which the cylindrical portion 34 is inserted is formed in the center. The disc spring 38 is formed obliquely from the inner peripheral portion to the outer peripheral portion, which is the periphery of the hole. ) To generate a biasing force along the vertical direction.
The disc spring 38 in the upper hydraulic chamber 36 is sandwiched between the upper surface of the piston body 35 and the inner surface on the upper end side of the hydraulic chamber 36 with the outer peripheral portion up and the inner peripheral portion down. Has been placed.

  The disc spring 39 in the lower hydraulic chamber 37 is sandwiched between the lower surface of the piston body 35 and the inner surface on the lower end side of the hydraulic chamber 37 with the outer peripheral portion facing down and the inner peripheral portion facing up. It is arranged in the state. Here, the upper and lower disc springs 38 and 39 are elastic bodies that are urging means for urging the piston body 35 in the opposite direction to face each other.

  When the machine provided with this toroidal continuously variable transmission is in a stopped state and no hydraulic pressure is applied to each of the hydraulic chambers 36 and 37, the two oppositely energizing these two are urged in opposite directions. The piston main body 35 is held by the disc springs 38 and 39 at a position substantially coinciding with the neutral position where the trunnion 15 does not tilt. That is, the two disc springs 38 and 39 constitute neutral position holding means for holding the trunnion 15 in the neutral position.

  These disc springs 38 and 39 have a spring load (elastic body load) that can at least support the self-weight of the trunnion assembly (assembly) including the trunnion 15 and the drive rod 29 associated with the trunnion 15, the drive piston 33, and other members. It has become. That is, the spring load (elastic body load) of the disc springs 38 and 39 is at least larger than a value that can support the mass of the trunnion assembly. Further, it is necessary for the drive device 32 to displace the drive piston 33 against the urging force of the disc springs 38 and 39, and the spring load of the disc springs 38 and 39 does not become much larger than the above value. Is preferred.

  Further, in the vertical arrangement in which the trunnion 15 is arranged on the driving device 32 as shown in FIG. 1, the lower disc spring 39 may be made stronger than the upper disc spring 38. Basically, the trunnion 15 may be in a substantially neutral position by the two disc springs 38 and 39 that urge the piston body 35 in opposite directions as described above.

  In this toroidal continuously variable transmission, when the transmission ratio is controlled using the differential value of the transmission ratio as a substitute characteristic of the offset amount of the trunnion 15 as described above, the toroidal continuously variable transmission is stopped (non- When the operation state is changed from the operation state to the operation state, the trunnion 15 is in the substantially neutral position and the offset amount of the trunnion 15 is substantially 0. Therefore, the trunnion 15 does not tilt and the trunnion 15 tilts. It does not hit the stopper that limits the range.

  After that, when the input side disk and the output side disk start to rotate and the speed ratio based on these rotational speeds can be measured, the trunnion by the drive device 32 is used to bring the current speed ratio close to the target speed ratio. 15 offset amounts are changed.

  The biasing means of the neutral position holding means is not limited to the disc springs 38 and 39, and for example, a wave spring may be used. Further, various springs and various elastic bodies can be used as the urging means as long as they can be arranged in the hydraulic chambers 36 and 37 and do not obstruct the movement of the drive piston 33 in the drive cylinder 31.

Furthermore, the arrangement position of the urging means is not limited to the hydraulic chambers 36 and 37 in the drive cylinder 31 as long as the position along the axis direction of the trunnion 15 can be urged to the neutral position. At other places such as between the lower surface of the pulley 40 for synchronizing the tilt angle of the trunnion 15 and the upper surface of the upper cylinder body 61, between the upper portion of the trunnion 15 and the upper portion of the trunnion 15 of the casing 50. A biasing means may be arranged.
Further, even in a double cavity type toroidal continuously variable transmission, the urging means (disc springs 38 and 39) may be provided in at least one of the left and right drive devices 32. This is because the yoke seesaw function (synchronization function) works because the pair of yokes 23A and 23B are provided.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 2, the toroidal type continuously variable transmission according to the second embodiment has a spring load of the disc springs 38, 39 on the disc springs 38, 39 of the toroidal type continuously variable transmission according to the first embodiment, that is, A ring seat 41 for adjusting the urging force (elastic force) is disposed between the upper disc spring 38 and the inner surface on the upper end side of the upper hydraulic chamber 36, and the ring seat 41 is arranged on the lower disc spring 39 and the lower hydraulic pressure. The chamber 37 is disposed between the inner surface on the lower end side.

  The ring seat 41 is a member in which a circular hole that is concentric with the disk is formed in the disk, and has an outer diameter similar to the outer diameter of the disc springs 38 and 39. As described above, the ring seat 41 comes into contact with the outer peripheral portions of the disc springs 38 and 39 sandwiched between the upper or lower surface of the drive piston 33 and the upper or lower inner surface of the drive cylinder 31. ing. In this state, the ring seat 41 is arranged between the disc springs 38 and 39 and the inner surface on the upper end side or the inner surface on the lower end side of the drive cylinder 31.

As a result, the disc springs 38 and 39 are compressed by the thickness of the ring seat 41, and the spring load of the disc springs 38 and 39 increases. That is, it is adjusted by the ring seat 41 so that the biasing force by the disc springs 38 and 39 is increased, and the ring seat 41 adjusts the biasing force of the disc springs 38 and 39 as the biasing means. It becomes an adjustment means.
In FIG. 2, the ring seats 41 are arranged corresponding to both of the pair of disc springs 38, 39. However, the ring seat 41 is arranged only on one of the disc springs 38, 39, and The biasing force of the disc springs 38 and 39 may be adjusted by the ring seat 41, and thereby the position of the drive piston 33 may be adjusted so that the trunnion 15 is in the neutral position.

For example, the pair of disc springs 38 and 39 may be the same, and the ring seat 41 may be disposed only on the lower disc spring 39 to which the load of the trunnion assembly is applied. 2, when the same disc springs 38, 39 are used as the pair of disc springs 38, 39 in the vertical arrangement shown in FIG. 2, the trunnion 15 is positioned below the neutral position due to the load of the trunnion assembly. Can be prevented.
The biasing force of the disc springs 38 and 39 by the ring seat 41 can be adjusted by the thickness of the ring seat 41. By selecting the ring seat 41 to be used from the ring seats 41 having different thicknesses. The urging force can be adjusted.

Further, the ring seat 41 arranged corresponding to each of the disc springs 38 and 39 does not have to be a single sheet, and by using one or a plurality of ring seats 41, the number of the ring seats 41 can be changed depending on the number of the ring seats 41. The spring load of the springs 38 and 39 may be adjusted.
Further, in the state without the ring seat 41, for example, in the case where there is a gap between the upper disc spring 38 and the inner surface on the upper end side of the drive cylinder 31 in the vertical arrangement shown in FIG. By arranging as a spacer, the biasing force of both the upper and lower disc springs 38, 39 may be applied to the drive piston 33. Also in this case, the biasing force of the disc springs 38 and 39 is adjusted, and the ring seat 41 functions as a biasing force adjusting unit.

  Further, members other than the ring seat 41 may be arranged between the disc springs 38 and 39 and the inner surface of the upper end side or the lower end side of the drive cylinder 31 to change the spring load by changing the spring compressibility. Good. In this case, when the urging means is other than the disc springs 38 and 39, the urging force adjusting means suitable for the shape of the urging means can be used.

Next, a third embodiment of the present invention will be described.
As shown in FIG. 3, in the toroidal type continuously variable transmission according to the third embodiment, compression coil springs 51 and 52 are driven cylinders in place of the disc springs 38 and 39 of the toroidal type continuously variable transmission according to the first embodiment. 31 cylinder spaces are provided. The compression coil springs 51 and 52 are respectively connected to upper and lower hydraulic chamber pistons 53 and 54 in the form of movable annular plates disposed between the upper and lower compression coil springs 51 and 52 and the piston body 35, respectively. The piston body 35 is urged downward and upward. The pistons 53 and 54 for the hydraulic chamber are configured such that the inner peripheral projections are in contact with the upper and lower surfaces of the piston body 35 to push the piston body 35. Seals 56 are provided on the outer peripheral surface and the inner peripheral surface of the hydraulic chamber pistons 53 and 54 to keep them oil-tight. The upper and lower compression coil springs 51 and 52 are elastic bodies that are urging means for urging the piston body 35 in the opposite direction to face each other. When the hydraulic pressure rises and the oil pressure is greater than the urging force of the compression coil springs 51 and 52, the piston body 35 moves.

Further, upper and lower stoppers 57 and 58 made of retaining rings or the like are provided on the outer peripheral wall surfaces forming the upper hydraulic chamber 36 and the lower hydraulic chamber 37, respectively. The upper and lower hydraulic chamber pistons 53 and 54 are brought into contact with the stoppers 57 and 58, so that the upper and lower hydraulic chamber pistons 53 and 54 are prevented from further approaching the piston body 35. . The upper and lower stoppers 57, 58 prevent the upper and lower hydraulic chamber pistons 53, 54 from pushing the piston body 35 beyond the position that substantially matches the neutral position where the trunnion 15 does not tilt.
Other configurations of the third embodiment are the same as those of the first embodiment of FIG.

  When the machine provided with this toroidal continuously variable transmission is in a stopped state and no hydraulic pressure is applied to each of the hydraulic chambers 36 and 37, the two oppositely energizing these two are urged in opposite directions. The compression coil springs 51 and 52 hold the piston main body 35 via the hydraulic chamber pistons 53 and 54 at a position substantially coincident with a neutral position where the trunnion 15 does not tilt. That is, the two compression coil springs 51 and 52 and the hydraulic chamber pistons 53 and 54 constitute neutral position holding means for holding the trunnion 15 in the neutral position.

  The compression coil springs 51 and 52 have a spring load (elastic body load) that can at least support the self-weight of the trunnion assembly (assembly) including the trunnion 15 and the drive rod 29 associated with the trunnion 15, the drive piston 33, and other members. It has become. That is, the spring load (elastic body load) of the compression coil springs 51 and 52 is larger than a value capable of supporting at least the mass of the trunnion assembly. Further, the drive device 32 needs to displace the drive piston 33 against the urging force of the compression coil springs 51 and 52, and the spring load of the compression coil springs 51 and 52 does not become so much larger than the above-described value. Is preferred.

  Further, as shown in FIG. 3, in the vertical arrangement in which the trunnion 15 is arranged on the driving device 32, the lower compression coil spring 52 may be made stronger than the upper compression coil spring 51. Basically, the trunnion 15 may be in a substantially neutral position by the two compression coil springs 51 and 52 that urge the piston body 35 in opposite directions as described above.

  In the toroidal type continuously variable transmission according to the third embodiment, the speed ratio is determined using the differential value of the speed ratio as a substitute characteristic of the offset amount of the trunnion 15 as in the toroidal type continuously variable transmission of the first embodiment. In the case of control, when the toroidal continuously variable transmission is changed from the stopped state (non-operating state) to the operating state, the trunnion 15 is in a substantially neutral position, and the offset amount of the trunnion 15 is substantially zero. Therefore, the trunnion 15 does not tilt, and the trunnion 15 does not hit the stopper that regulates the tilt range at the time of activation.

  Further, in the first embodiment of FIG. 1, since the disc springs 38 and 39 are arranged directly in the hydraulic chambers 36 and 37, the thrust component of the disc springs 38 and 39 is calculated when the variator input torque is calculated from the differential pressure. However, in the third embodiment, the compression coil springs 51 and 52 push the piston main body 35 through the hydraulic chamber pistons 53 and 54. Therefore, if the hydraulic pressure rises, an accurate input torque can be obtained from the differential pressure. Can be calculated.

  In the third embodiment, since the upper and lower stoppers 57 and 58 are provided, the upper and lower hydraulic chamber pistons 53 and 54 exceed the position where the piston body 35 substantially coincides with the neutral position where the trunnion 15 does not tilt. The position of the piston main body 35 can be determined without being pushed. That is, if the upper and lower stoppers 57 and 58 are not provided, the piston body 35 is positioned at a position where the urging forces of the two compression coil springs 51 and 52 are balanced, so that the side slip force is increased and the speed change is performed. There is a risk of it. Even if the spring characteristics of the compression coil springs 51 and 52 are slightly different, the position of the piston body 35 can be determined by the upper and lower stoppers 57 and 58.

  The biasing means of the neutral position holding means is not limited to the compression coil springs 51 and 52. For example, various springs such as a disc spring and a wave spring and various elastic bodies can be used as the biasing means.

Next, a fourth embodiment of the present invention will be described.
As shown in FIG. 4, the toroidal continuously variable transmission according to the fourth embodiment uses the differential value of the transmission ratio as a substitute characteristic of the offset amount of the trunnion 15, the first embodiment, the second embodiment, and the third embodiment. A part of the control method is changed. The structure of the toroidal continuously variable transmission according to the third embodiment is the same as that of the first embodiment shown in FIG. The structure of the toroidal continuously variable transmission according to the fourth embodiment may be the same as that of the toroidal continuously variable transmission according to the second or third embodiment.

  In the toroidal-type continuously variable transmission of the fourth embodiment, during normal times, as in the first embodiment, the gear ratio is obtained from the ratio of the rotational speed of the input side disk 2 and the rotational speed of the output side disk 3, By using this gear ratio and the differential value of this gear ratio, the supply / discharge of hydraulic pressure to / from the drive device 32 is controlled, so that the gear ratio of the toroidal type continuously variable transmission is controlled to a desired gear ratio. ing.

  However, in this example, for example, in a vehicle or other machine equipped with a toroidal-type continuously variable transmission, when the vehicle is in a running state (operating state) from a stopped state (stopped state), the input side disk 2 and the output side disk For example, the first hydraulic chamber of the drive cylinder 31 of the drive device 32 does not perform the above-described normal control when the rotation speed of the disk 3 is equal to or less than a set value (for example, 300 rpm) that is a set reference value. 36 and the second hydraulic chamber 37 are controlled to have the same hydraulic pressure. Accordingly, even when the trunnion 15 is in the neutral position by the two disc springs 38 and 39 when the vehicle is stopped, the drive piston 33 of the drive device 32 is not displaced even when the vehicle is moved from the stopped state. The trunnion 15 is held at the neutral position, and the speed ratio is not changed.

That is, as shown in the flowchart of FIG.
It is determined whether or not the rotational speeds of the input side disk 2 and the output side disk 3 are equal to or higher than a reference value (set value) (step S1). By supplying the same hydraulic pressure to the two (step S2), the hydraulic pressures of the two hydraulic chambers 36 and 37 are equalized, and the position of the drive piston 33 is held at a position where the trunnion 15 is in the neutral position.
When the rotational speeds of the input side disk 2 and the output side disk 3 are equal to or higher than the reference value, the control of the hydraulic pressure of the driving device 32 using the differential value of the gear ratio is started as described above (step S3). ).

In this toroidal-type continuously variable transmission, the trunnion 15 is moved to the neutral position by the above-described disc springs 38 and 39 in the stopped state until the rotational speeds of the input side disk 2 and the output side disk 3 become equal to or higher than a reference value. Is maintained even when the state becomes the traveling state, and the gear ratio is not changed. Therefore, in the state where the output of the signal from the sensor for detecting the rotation of the input side disk and the output side disk is unstable, the transmission ratio is obtained based on the unstable signal and the differential value of the transmission ratio is obtained. It is possible to prevent the transmission ratio from becoming unstable by controlling the transmission ratio based on the transmission ratio and the differential value.
In this case, since the state where the trunnion 15 is in the neutral position is maintained at the start of traveling by the disc springs 38 and 39 in the stopped state as described above, even if the speed ratio is not temporarily controlled, the speed ratio Is constant and no problem occurs.

  That is, if the hydraulic pressure in each hydraulic chamber is made constant in the drive device 32 with the trunnion 15 being offset, the gear ratio may continue to change to the Low side or the High side at a constant rate. When the same hydraulic pressure is supplied to the two hydraulic chambers, the gear ratio does not change because the trunnion 15 is in the neutral position.

  In the above-described processing, in step S1, it is determined whether or not the rotational speeds of both the input side disk 2 and the output side disk 3 are equal to or higher than a reference value. That is, when either one of the input side disk 2 and the output side disk 3 is still below the reference value, the rotational speed is determined to be below the reference value. Note that when either one of the input side disk 2 and the output side disk 3 becomes equal to or higher than the reference value, it may be determined that the rotation speed becomes equal to or higher than the reference value. Further, only the rotational speed of either the input side disk 2 or the output side disk 3 is compared with the reference value, and it is determined whether the rotational speed compared with the reference value is less than or equal to the reference value. Also good.

In addition, the above process is actually repeatedly performed at short time intervals when the vehicle stops and travels, and the rotational speeds of the input side disk 2 and the output side disk 3 become equal to or higher than a reference value. When the shift control is performed, the process ends.
Further, although the reference value is set to 300 rpm, for example, it is necessary to determine the reference value corresponding to the characteristics of the sensors that detect the rotation speeds of the input side disk 2 and the output side disk 3, and the reference value is limited to 300 rpm. It is not a thing. That is, it is preferable to set a value that allows the sensor to stably detect the rotational speeds of the input side disk 2 and the output side disk 3 or a value close thereto as a reference value.

Next, a fifth embodiment of the present invention will be described.
As shown in FIG. 5, the characteristic parts of the toroidal type continuously variable transmission according to the fifth embodiment are the structure (characteristics) of the piston seal 71 provided in the drive device 32 and the control method of the drive device 32. Since the configuration and operation of the second embodiment are the same as those of the conventional configuration and operation described above, only the characteristic portions of the fifth embodiment will be described below, and the other portions are denoted by the same reference numerals as those in FIGS. A brief explanation will be given.

  The toroidal continuously variable transmission according to the fifth embodiment increases the frictional force of the piston seal 71 as described later, instead of the disc springs 38 and 39 according to the first embodiment, and the drive device is in a non-operating state. That is, the trunnion 15 is moved to the neutral position before the engine is stopped and the driving device is not operated.

  As described above, the structure of the toroidal type continuously variable transmission according to the fifth embodiment is the same as that of the prior art except for the piston seal 71. Note that in a device that includes a cylinder and a piston and is hydraulically operated, a piston seal is indispensable, and the piston seal 71 is conventionally provided.

In the fifth embodiment, unlike normal, the piston seal 71 having a large frictional force is provided.
In the fifth embodiment, a plurality of piston seals 71 are fixed to the outer peripheral surface of the drive piston 33 including the cylindrical portion 34 into which the drive rod 29 is inserted and the piston main body 35. For example, the piston seal 71 includes an outer peripheral surface of the piston main body 35, a portion above the piston main body 35 of the cylindrical portion 34, a portion below the piston main body 35 of the cylindrical portion 34, and a portion further below the cylindrical portion 34. It is attached to four places. In addition, an annular mounting groove is provided at each mounting position of the piston seal 71, and the piston seal 71 is fitted and mounted in these mounting grooves. Moreover, the outer peripheral surface of the piston seal 71 protrudes outside the mounting groove.

The piston seal 71 above the piston main body 35 is above the upper hydraulic chamber 36 that becomes the cylinder main body of the upper cylinder body 61 constituting the drive cylinder 31, and the cylindrical portion 34 with the drive rod 29 inserted inside penetrates. It is in contact with the inner peripheral surface of the part. Further, the piston seal 71 of the piston main body 35 is in contact with the inner surface of the portion that becomes the cylinder main body of the upper cylinder body 61 of the drive cylinder 31.
The two piston seals 71 below the piston main body 35 are in contact with the inner peripheral surface of the portion through which the cylindrical portion 34 with the drive rod 29 inserted inside the lower cylinder body 62 constituting the drive cylinder 31 penetrates. .

The frictional force of these piston seals 71 on the drive cylinder 31 (upper cylinder body 61 and lower cylinder body 62) is made larger than the gravity acting on the total weight of all members including the trunnion 15 driven by the drive device 32. ing.
The members driven by the drive device 32 include a trunnion 15 having a pivot shaft 14, a drive rod 29 attached to the pivot shaft 14, a power roller 11, a displacement shaft 23, an outer ring 28, a thrust ball bearing 24, a thrust needle bearing 25, and the like. It is a member which is driven by the drive device 32 and is moved in the axial direction of the pivot 14.

  Thus, since the frictional force of the piston seal 71 against the drive cylinder 31 is greater than the gravity acting on the total weight of all members including the trunnion 15 driven by the drive device 32, the drive device 32 is a toroidal type. A driving device such as a trunnion when the engine that supplies torque to the continuously variable transmission becomes inactive due to a stop or the like, the hydraulic pressure is not applied to the driving device 32, and the trunnion is in a neutral position. The member driven by 32 can be prevented from moving downward due to gravity.

  For example, when the toroidal-type continuously variable transmission is vertically arranged as shown in FIG. 5, the trunnion 15 arranged in the neutral position is moved downward in the figure by gravity due to the frictional force of the four piston seals 71. It will not slip down. That is, the frictional force of the piston seal 71 with respect to the drive cylinder 31 is set to a magnitude that can restrict the movement of the trunnion 15 in the direction of the pivot 14 due to gravity in a state where no hydraulic pressure is applied to the drive device 32.

  A piston seal 71 provided in the cylindrical portion 34 other than the piston main body 35 may be provided on the drive cylinder 31 side. In this case, a frictional force is generated between the piston seal 71 and the drive piston 33.

  The frictional force between the piston seal 71 and the drive cylinder 31 or the drive piston 33 is sized so as to prevent the trunnion 15 from moving in the axial direction due to gravity or the like when the drive device 32 is in an inoperative state as described above. In this case, the piston seal 71 is made of a material having higher elasticity, or the piston seal 71 is made thicker in the radial direction or the axial direction, thereby increasing the driving cylinder 31 of the piston seal 71. The frictional force is increased by increasing the pressing force against the inner peripheral surface of the motor or the outer peripheral surface of the drive piston 32. Further, the frictional force is increased by increasing the contact area of the piston seal 71 to the inner peripheral surface of the drive cylinder 31 or the outer peripheral surface of the drive piston 32. These may be combined to increase the frictional force.

Further, in the fifth embodiment, the trunnion 15 is disposed in the neutral position when the drive source for inputting torque to the toroidal-type continuously variable transmission such as the engine of the vehicle stops and the drive device 32 becomes inoperative. In this manner, the supply of hydraulic pressure to the driving device 3 is controlled. The control device that controls the supply of hydraulic pressure serves as drive control means for controlling the drive device 32.
At this time, when the vehicle is stopped and the engine is stopped in the idling state, immediately before the engine is stopped, the rotational speed of the input side disk 2 and the rotational speed of the output side disk are set as described above. The speed ratio is obtained based on the rotational speed ratio, the speed of change of the speed ratio (differential value of the speed ratio) is calculated, the movement of the trunnion 15 is estimated from the calculated differential value of the speed ratio, and based on this estimation The trunnion 15 may be moved to the neutral position by performing feedback control.

  Thereby, after the drive device is inactivated, the trunnion 15 that is in the neutral position as described above can be held in the neutral position by the frictional force of the piston seal 71 described above. Accordingly, the piston seal 71 and the drive control means constitute neutral position holding means for holding the trunnion 15 in the neutral position.

  In the toroidal type continuously variable transmission according to the fifth embodiment, the transmission ratio is determined by using the differential value of the transmission ratio as a substitute characteristic of the offset amount of the trunnion 15 as in the toroidal type continuously variable transmission of the first embodiment. In the case of control, when the toroidal continuously variable transmission is changed from the stopped state (non-operating state) to the operating state, the trunnion 15 is in a substantially neutral position, and the offset amount of the trunnion 15 is substantially zero. Therefore, the trunnion 15 does not tilt, and the trunnion 15 does not hit the stopper that regulates the tilt range at the time of activation.

  In the fifth embodiment, since the piston seal 71 is also used as means for holding the trunnion 15 in the neutral position, members such as the aforementioned disc springs 38 and 39 that have not been conventionally used are not required. Therefore, it is possible to suppress an increase in cost and weight of the toroidal-type continuously variable transmission by adding a new member.

In each of the above-described embodiments, when the gear ratio is controlled by displacing the trunnion from the neutral position where the trunnion does not tilt by the drive device along the axial direction of the pivot shaft, The differential value of the gear ratio obtained from the rotational speed of the output side disk was applied to a toroidal continuously variable transmission that is used as a substitute characteristic of the amount of displacement along the axial direction of the pivot from the neutral position of the trunnion.
However, the present invention is not limited to this, and can deal with the following. That is, if the hydraulic pressure in the hydraulic cylinder (speed increasing hydraulic pressure chamber, deceleration hydraulic pressure chamber) in the driving cylinder 31 of the driving device 32 that supports the power roller 11 (trunnion 15) does not rise (does not act), the power roller Although the center 11 may be offset from the center of the disks 2 and 3 and hunting may occur, according to the toroidal-type continuously variable transmission of each of the above embodiments, the trunnion is provided when the drive device 32 is in an inoperative state. Since the neutral position holding means for holding the position along the axial direction of the 15 pivots 14 in a state substantially coincident with the neutral position where the trunnion 15 does not tilt is provided, the time during which the hydraulic pressure rise in the hydraulic chamber is insufficient is The vertical motion (reciprocating motion) of the piston main body 35 of the drive device 32 can be stopped, thereby preventing hunting or speeding up of the engine (prime motor). It is possible to achieve convergence. That is, when the hydraulic pressure in the hydraulic chamber is low, the vertical motion (reciprocating motion) of the piston main body 35 of the drive device 32 is fixed, and when the hydraulic pressure increases, the drive device 32 moves in the same manner as before.

  The present invention includes various half-toroidal continuously variable transmissions such as a single cavity type and a double cavity type, and various types such as an infinite gear ratio transmission (IVT) in which a half-toroidal continuously variable transmission and a planetary gear are combined. It can be applied to any transmission.

2 Input side disk 3 Output side disk 11 Power roller 14 Pivot 15 Trunnion 31 Drive cylinder 32 Drive device 33 Drive piston 34 Cylindrical portion (member on the drive piston side)
35 Piston body (member on the drive piston side)
36 Hydraulic chamber 37 Hydraulic chamber 38 Disc spring (biasing means, neutral position holding means)
39 Belleville spring (biasing means, neutral position holding means)
41 Ring seat (bias force adjusting means)
51 Compression coil spring (biasing means, neutral position holding means)
52 Compression coil spring (biasing means, neutral position holding means)
53 Piston for hydraulic chamber 54 Piston 61 for hydraulic chamber Upper cylinder body (member on the drive cylinder side)
62 Lower cylinder body (drive cylinder side member)
71 piston seal

Claims (7)

An input side disk and an output side disk that are supported concentrically and rotatably with their inner side surfaces facing each other, and a power roller sandwiched between the input side disk and the output side disk And move along the axial direction of a pair of pivots that are concentric with each other and are twisted with respect to the central axis of the input side disk and the output side disk and tilt about the pivot axis. And a toroidal continuously variable transmission comprising a plurality of trunnions that rotatably support the power rollers, and a drive device that displaces the trunnions along the axial direction of the pivot.
When the drive device is in a non-operating state, neutral position holding means is provided that holds the position of the trunnion along the axial direction of the pivot in a state that substantially matches the neutral position where the trunnion does not tilt. Toroidal-type continuously variable transmission. An input side disk and an output side disk that are supported concentrically and rotatably with their inner side surfaces facing each other, and a power roller sandwiched between the input side disk and the output side disk And move along the axial direction of a pair of pivots that are concentric with each other and are twisted with respect to the central axis of the input side disk and the output side disk and tilt about the pivot axis. And a plurality of trunnions that rotatably support the power rollers, and a drive device that displaces the trunnions along the axial direction of the pivot,
When the gear ratio is controlled by displacing the trunnion from the neutral position where the trunnion does not tilt by the driving device along the axial direction of the pivot, the rotational speed of the input side disk and the output side disk is determined. In the toroidal type continuously variable transmission that uses the obtained differential value of the transmission ratio as a substitute characteristic of the amount of displacement along the axial direction of the pivot from the neutral position of the trunnion,
A toroidal-type continuously variable means comprising neutral position holding means for holding the position of the trunnion along the axial direction of the pivot shaft in a state substantially coinciding with the neutral position when the drive device is in an inoperative state. transmission. The drive device includes a drive cylinder and a drive piston that divides the inside of the drive cylinder into two hydraulic chambers and that moves linearly based on the hydraulic pressure in the hydraulic chambers to displace the trunnion along the axial direction of the pivot. And
The neutral position holding means is provided in each of the two hydraulic chambers, and includes a biasing means for biasing the position of the drive piston toward the side where the trunnion is in the neutral position. The toroidal-type continuously variable transmission according to claim 1 or 2, characterized by the above.   4. The toroidal type non-rotating device according to claim 3, wherein each of the two urging means urges the driving piston via a hydraulic chamber piston movably provided in the two hydraulic chambers. Step transmission.   5. The toroidal continuously variable transmission according to claim 3, wherein the biasing unit includes a biasing force adjusting unit that adjusts a biasing force. The drive device includes a drive cylinder and a drive piston that divides the inside of the drive cylinder into two hydraulic chambers and that moves linearly based on the hydraulic pressure in the hydraulic chambers to displace the trunnion along the axial direction of the pivot. And an annular piston seal disposed between the inner peripheral surface of the drive cylinder side member and the outer peripheral surface of the drive piston side member,
The neutral position holding means includes the piston seal, and drive control means for moving the trunnion to the neutral position by the drive device immediately before the drive device becomes inoperative.
In the piston seal, when the member on the drive cylinder side and the member on the drive piston side slide through the piston seal, the piston seal and the member on the drive cylinder side or the member on the drive piston side The frictional force generated between the first and second members is greater than the gravity acting on the total weight of all the members that are driven by the driving device and move together. Toroidal continuously variable transmission. A control method for a toroidal continuously variable transmission according to any one of claims 1 to 6,
When the rotational speed of both or one of the input side disk and the output side disk is less than a predetermined value, the drive device moves the trunnion along the axial direction of the pivot from a neutral position where the trunnion does not tilt. A toroidal continuously variable transmission characterized in that a shift control for controlling a transmission ratio by displacing is prohibited, and the drive device is controlled so that a position along the pivot direction of the trunnion is set to a substantially neutral position. Control method.

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