JPH07233860A - Speed change controller for fritional type continuously variable transmission - Google Patents

Abstract

PURPOSE:To correct the torque shift in correspondence with the torque and speed change ratio, by allowing a spool to be interlocked with the shift in the axial direction of a thrust cam device. CONSTITUTION:In an oil passage 166 for the communication between the low side oil chamber 130 of a hydraulic cylinder device and a speed change control valve 150, a discharge valve 500 for varying the differential pressure between the all pressure in a high side oil chamber 128 and the oil pressure in the low side oil chamber 130 is installed. The discharge valve 500 has a discharge hole 501 for the discharge of the oil pressure in the discharge valve 500 and a spool 504 which can vary the oil pressure discharged from the discharge hole 501 and the oil pressure supplied from an oil passage 166, by the shift in the axial direction. The spool 504 is interlocked with the shift in the axial direction of a thrust cam device 400, and is constituted so as to be shiftable in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a friction wheel type continuously variable transmission.

[0002]

2. Description of the Related Art The following is a conventional shift control device for a continuously variable transmission. For example, Japanese Patent Laid-Open No. 2-8556
The one disclosed in Japanese Unexamined Patent Publication (Kokai) No. 0-57, in which an input disc, an output disc, a friction roller that makes frictional contact with both discs, a friction roller is rotatably supported, and is rotatable around a rotation shaft portion It has a roller support member movable in the axial direction and a hydraulic cylinder having a high-side oil chamber and a low-side oil chamber for moving the roller support member to the high side and the low side in the axial direction of the rotating shaft portion, respectively. A high-side discharge valve and a low-side discharge valve capable of discharging the hydraulic pressure of the oil passage are provided in the oil passages that communicate with the high-side oil chamber and the low-side oil chamber, respectively. The discharge valve is opened by the valve opening mechanism provided on the roller support member when the roller support member is rotated to the minimum gear ratio position, and the high side discharge valve is opened, so that the roller support member is at the maximum gear ratio position. Low-side discharge valve when the rotation is in an open state until the high side discharge valve and the low-side discharge valve in the cases other than the above are configured to be held in the closed state. Further, Japanese Patent Application Laid-Open No. 2-292562 discloses that the gear ratio is controlled according to the operation of the gear shift actuator, and the input rotational speed or gear ratio of the continuously variable transmission is controlled based on the operating conditions. A target value determining means for determining a target value, an engine torque detecting means for detecting the engine torque, and a target value determined by the target value determining means on the basis of operating conditions are set according to the torque detected by the engine torque detecting means. Target value correction means for making correction to obtain a correction target value, actual value detection means for detecting the actual value of the input rotation speed or gear ratio of the continuously variable transmission, and the corrected target value and the actual value corrected by the target value correction means Feedback control means for feedback-controlling the shift actuator according to the deviation from the actual value detected by the value detection means.

[0003]

However, the above-mentioned conventional shift control device for a friction wheel type continuously variable transmission has the following problems. That is, in the one disclosed in Japanese Patent Application Laid-Open No. 2-85560, the discharge valve is opened only when the friction roller rotates to the maximum and minimum gear ratio positions to prevent deviation from the target gear ratio. However, if a large torque is applied when the friction roller is not located at the maximum or minimum gear ratio position, the eccentric shaft that connects the friction roller and the roller support member may be deformed and the tip of the friction roller and the roller support member may be deformed. The distance from the installed precess cam changes, and the positional relationship between the spool and sleeve of the transmission valve changes. Therefore, there is a problem that a deviation occurs between the target gear ratio and the actual gear ratio (torque shift). Further, in the system disclosed in Japanese Patent Laid-Open No. 2-292562, the accuracy of torque detection by the engine torque detection means is considerably poor, so that an accurate correction target value cannot be set. Therefore, there is a problem that the correction cannot be performed accurately. The present invention is intended to solve such a problem.

[0004]

According to the present invention as set forth in claim 1, as shown in FIG. 1, the hydraulic pressure of the high side oil chamber and the low side oil chamber are interlocked with the axial movement of the thrust cam device. The above problem is solved by providing a discharge valve capable of changing the differential pressure from the hydraulic pressure. That is, the shift control device for a friction wheel type continuously variable transmission according to the present invention frictionally contacts both the input disc (18), the output disc (20), and the toroidal groove formed by the both discs. And the friction roller (22) arranged in this manner and the rear surface of the input disk (18) opposite to the contact surface of the friction roller (22), and a thrust force corresponding to the input torque is applied to the input disk (18). The generated thrust cam device (400) and the friction roller (22) are rotatably supported via an eccentric shaft (80), and a rotary shaft portion (8) orthogonal to the shaft centers of both disks.
3b) is rotatable about the rotation shaft portion (83
b) an axially movable roller support member (83),
A hydraulic cylinder device having a high-side oil chamber (128) and a low-side oil chamber (130) capable of driving the roller support member (83) on the high side and the low side in the axial direction of the rotary shaft portion (83b), respectively. , A shift control valve (150) for controlling the hydraulic pressure of the hydraulic cylinder device, and an oil passage (that connects the low-side oil chamber (130) of the hydraulic cylinder device and the shift control valve (150). 166) is provided with a discharge valve (500) for changing the differential pressure between the hydraulic pressure of the high-side oil chamber (128) and the hydraulic pressure of the low-side oil chamber (130). Valve (50
0) which is capable of discharging the hydraulic pressure in 0) and the spool in which the hydraulic pressure discharged from the discharging hole (501) and the hydraulic pressure supplied from the oil passage (166) are variable by the axial movement of the discharging hole (501). (504), and the spool (50
4) is configured to move in the axial direction of the thrust cam device (400) in conjunction with the axial movement of the thrust cam device (400). Further, as shown in FIG. 2, the shift control device for a friction wheel type continuously variable transmission according to the present invention comprises a low-side oil chamber (130) and a shift control valve (150) of a hydraulic cylinder device. A discharge valve (500) for changing the differential pressure between the hydraulic pressure of the high-side oil chamber (128) and the hydraulic pressure of the low-side oil chamber (130) is provided in the communicating oil passage (166). A differential pressure detection valve (510) that operates according to the differential pressure of these hydraulic pressures is provided in an oil passage that connects the high side oil chamber (128) and the low side oil chamber (130), and the discharge valve ( 500 is a discharge valve (5)
(00) is configured to be moved in the axial direction by a discharge hole (501) capable of discharging the hydraulic pressure and a differential pressure inspection valve (510). The oil pressure discharged from (501) and the oil pressure supplied from the oil passage (166) are variable (50
4) and are included. The reference numerals in the parentheses indicate the corresponding members of the embodiments described later.

[0005]

According to the first aspect of the present invention, when a torque is input, a force corresponding to the torque is applied to the friction roller in the rotation direction at the contact portion between the friction roller and the input disk and the output disk. Since the eccentric shaft is deformed by this force, a shift occurs between the offset amount of the friction roller and the position of the shift control valve.
Therefore, it tries to stabilize in a state in which the actual gear ratio deviates to the low side from the target gear ratio. That is, a torque shift on the low side occurs. On the other hand, since the input torque is also input to the thrust cam device, a thrust is generated in this and presses the input disk toward the friction roller. As a result, the input disc, the output disc, the roller support member, and the like are deformed, and the thrust cam device moves in the opposite direction to the input disc while causing a phase shift to absorb the deformation. Moves in a direction in which the hydraulic pressure supplied from the oil passage is reduced and the hydraulic pressure discharged from the discharge hole is increased. As a result, the oil pressure in the low-side oil chamber can be reduced, so that only the low-side oil pressure is reduced and the differential pressure from the high-side oil pressure is increased, so that the gear shifts to the high side. Therefore, by these actions, the torque shift is corrected as a whole. Further, even with the same torque, as the gear ratio is larger (low side), the transmission force of the contact portion between the friction roller and both discs becomes larger, and the force applied to the eccentric shaft and the roller support member becomes larger, and the deformation amount of this also increases. As the torque shift amount increases, the torque shift amount increases. However, since the amount of movement of the thrust cam device changes according to the amount of deformation of the roller support member, the discharge valve also
As the torque shift amount increases, the hydraulic pressure supplied from the oil passage can be decreased and the hydraulic pressure discharged from the discharge hole can be increased. That is, the greater the reduction ratio, the greater the amount of decrease in the hydraulic pressure in the low-side oil chamber. Eventually, the torque shift is corrected according to the torque and the gear ratio. Further, according to the second aspect of the present invention, when the torque is input, like the first embodiment, the actual gear ratio tries to stabilize in a state in which the gear ratio is shifted to the lower side than the target gear ratio. By the way, at this time, the high-side hydraulic pressure rises in accordance with the transmission force of the friction roller and both discs, and becomes higher than the low-side hydraulic pressure. Therefore, the differential pressure inspection valve causes the spool of the discharge valve to move in a direction of decreasing the hydraulic pressure supplied from the oil passage and increasing the hydraulic pressure discharged from the discharge hole. As a result, the oil pressure in the low-side oil chamber can be reduced, so that only the low-side oil pressure is reduced and the differential pressure from the high-side oil pressure is increased, so that the gear shifts to the high side. By these functions, the torque shift is corrected as a whole. Further, as the differential pressure between the hydraulic pressure in the high-side oil chamber and the hydraulic pressure in the low-side oil chamber increases, the differential pressure detection valve causes the discharge valve to increase the hydraulic pressure discharged from the discharge hole and increase the hydraulic pressure supplied from the oil passage. Can be reduced. After all, also in this embodiment, the entire torque shift amount can be corrected according to the magnitude of the torque and the gear ratio.

[0006]

EXAMPLE FIG. 3 shows the structure of the entire continuously variable transmission. A torque converter 12 is connected to a drive plate 10 that is integral with the output shaft of the engine. The torque converter 12 has a lock-up clutch 12a, and by controlling the hydraulic pressure in the lock-up oil chamber 12b, the pump impeller 12c on the input side and the turbine runner 12d on the output side can be mechanically connected or disconnected. Is. An oil pump drive shaft 87 is connected to the cover 12e of the torque converter 12. The oil pump drive shaft 87 is connected to the oil pump 15 and can drive it. The oil pump 15 is arranged on the opposite side of the torque converter 12 with a friction wheel type continuously variable transmission mechanism 16 described later interposed therebetween.
In addition, the turbine runner 12d of the torque converter 12
Is connected to the hollow input shaft 14. A friction wheel type continuously variable transmission mechanism 16 is connected to the input shaft 14. The friction wheel type continuously variable transmission mechanism 16 includes an input disc 18, an output disc 20, and a friction roller 22 for transmitting a rotational force therebetween.
And have. The contact surfaces of the input disk 18 and the output disk 20 with the friction roller 22 are toroidal surfaces. The inclination of the shaft 24 of the friction roller 22 can be adjusted by a mechanism described later shown in FIG. An input disc 18 is connected to the input shaft 14, while a gear 26 is provided on the output disc 20 so as to rotate integrally therewith. Gear 26
Meshes with a gear 30 integral with the idler shaft 28.
The idler shaft 28 has a gear 32 that always rotates integrally with the idler shaft 28.
Further, a gear 34 rotatably supported with respect to the idler shaft 28 is provided. The gear 34 is a reverse clutch 36.
Can be connected to the gear 30 so as to rotate integrally therewith. The idler shaft 28 is rotated only in the forward direction by a one-way clutch 31 attached to the casing, and is not rotated in the reverse direction. This is to prevent the friction wheel type continuously variable transmission mechanism 16 from rotating in the direction opposite to the engine rotation direction due to the reverse driving force from the wheel side. A gear 40 is rotatably supported on the other idler shaft 38 arranged in parallel with the idler shaft 28, and a gear 42 is connected so as to always rotate integrally. The gear 40 can be connected by a forward clutch 44 so as to rotate integrally with the idler shaft 38. Gear 40
Meshes with the gear 32. Gear 34 is in constant mesh with final gear 48. The final gear 48 has a pair of pinion gears 52 and 5 that constitute a differential device 50.
4 is attached to the pinion gears 52 and 5
4 and a pair of side gears 56 and 58 mesh with each other, and the output shafts are connected to the side gears 56 and 58, respectively. With such a configuration, when the forward clutch 44 is engaged, the output shaft rotates in the forward direction, and when the reverse clutch 36 is engaged, the output shaft rotates in the backward direction. Further, the gear ratio can be continuously changed by controlling the contact state of the friction roller 22 of the friction wheel type continuously variable transmission mechanism 16 with the input disc 18 and the output disc 20.

FIG. 4 shows the friction wheel type continuously variable transmission mechanism 16 in detail. The input shaft 14 is rotatably supported by a casing 67 via a ball bearing 65 and a needle bearing 66. The input shaft 14 and the ball bearing 6
A spacer 68 is provided between the spacers 5 and 5. A disc spring 70 is provided between the spacer 68 and the loading nut 69 screwed onto the input shaft 14. As a result, the reaction force of the disc spring 70 acts so as to push the input shaft 14 rightward in the drawing. The tip of the loading nut 69 is prevented from loosening by a pin 71 that enters the groove 14a of the input shaft 14. A plurality of holes 69a for inserting the pins 71 are provided, and a plurality of grooves 14a for the input shaft 14 are also provided.
Fine adjustment of the fixed position of 9 is possible. Pin 7
The screw 1 is held by a screw 72. Input shaft 14
The output disc 20 is rotatably supported by a bearing 73. The output disc 20 is provided with output gears 26 so as to rotate integrally via keys 74 arranged at two symmetrical positions. The gear 26 is supported by the casing 67 via a ball bearing 75. An input disk 18 is provided on the input shaft 14 via a bearing 76 so as to be rotatable and axially movable. The cam flange 7 is provided on the back side of the input disk 18, that is, on the side opposite to the side facing the output disk 20.
7 is provided. The cam flange 77 is spline-coupled to the input shaft 14, and the shoulder portion 78 of the input shaft 14 prevents the cam flange 77 from moving leftward in FIG. A cam roller 79 is provided between the cam surfaces 18a and 77a of the input disk 18 and the cam flange 77 which face each other. The cam surfaces 18a and 77a and the cam roller 79 are shaped so that when the cam flange 77 and the input disk 18 rotate relative to each other, a force for pressing the input disk 18 to the right in FIG. 4 is generated. The cam flange 77, the cam roller 79, and the cam surface 18 a of the input disk 18 constitute a thrust cam device 400. Input disk 1
8 and the friction roller 22 arranged in a toroidal groove formed by the surfaces of the output disk 20 facing each other are rotatably supported by a shaft 80 via a bearing 81. The friction roller 22 is supported in the thrust direction by a ball bearing 82.
The ball bearing 82 is supported by the roller support member 83. Friction roller 22, ball bearing 8
2. The roller support member 83 is prevented from coming off by snap rings 84 and 85 provided at both ends of the shaft 80. The sleeve 86 is inserted in the inner diameter portion of the input shaft 14,
It is retained by a snap ring 97. The sleeve 86 has a diameter smaller than the inner diameter of the input shaft 14 except for both ends where the O-rings 96 and 95 are provided, and an oil passage 88 is formed by a clearance having an annular cross section between the both. The input shaft 14 is provided with radial holes 94, 93, 92 and 91 communicating with the oil passage 88. Further, the input shaft 14 is provided with a groove 101 and a hole 102 for receiving oil from the hole 90 of the casing 67. The groove 101 is sealed by a seal ring 103. An oil pump drive shaft 87 penetrates the inner diameter portion of the sleeve 86. An oil passage 89 for the lockup control hydraulic pressure of the torque converter 12 is formed by a clearance having an annular cross section between the inner diameter portion of the sleeve 86 and the outer diameter portion of the oil pump drive shaft 87.

FIG. 5 shows a sectional view taken along line 5-5 of FIG. The above-mentioned roller support member 83 includes the upper and lower rotary shaft portions 83a and 83a.
In b, it is supported by spherical bearings 110 and 112 so as to be rotatable and movable in the vertical direction. Spherical bearing 1
10 is held by a bearing support member 114, and the bearing support member 114 is supported by a link post 116 fixed to the casing 67. Further, the spherical bearing 112 is also supported by the bearing support member 118, and the bearing support member 118 is fixed to the upper control valve body 200.
Supported by. The upper control valve body 200 is attached to the casing 67. The roller support member 83 has an extension shaft portion 83c provided concentrically with the rotation shaft portion 83b. The extension shaft portion 83c is formed by integrally fixing another member to the rotation shaft portion 83b. A piston 124 is provided on the outer circumference of the extension shaft portion 83c. The piston 124 is the cylinder 12 provided in the upper control valve body 200.
It fits in 6. A high-side oil chamber 128 is formed above the piston 124, and a low-side oil chamber 130 is formed below the piston 124. The piston 124 and the cylinder 126 form a hydraulic cylinder device. The low-side oil chamber 130 on the right side of the drawing has a hole 302 provided in the piston 124, a clearance 304 between the piston 124 and the small diameter portion of the extension shaft portion 83c, holes 306 and 308 provided in the roller support member 83 (note that The opening of the hole 306 is blocked by the ball 310), so that the hole 308
Communicates with the opening. Also, the race 312 of the bearing 82 is provided with a hole 314. The roller support member 83 on the left side of the drawing has substantially the same oil passage (hole 30).
2, clearance 304, holes 306 and 308) are provided, except that the hole 302 communicates with the upper high-side oil chamber 128. The holes 306 and 308 are connected by an annular groove 316. The left and right pistons 124 have the same shape except that the positions of the holes 302 are different. The upper end of the piston 124 is in contact with the roller support member 83 via the spacer 132, and the piston 12
The lower end of 4 is in contact with the cam 136 via the spacer 134. The cam 136 is attached by a bolt 138 so as to rotate integrally with the extension shaft portion 83c. The cam 136 is attached to the extension shaft portion 83c on the right side in FIG. 5, and is not provided on the extension shaft portion 83c on the left side. Note that the left and right friction rollers 22, the roller support member 83, etc. are basically symmetrical with respect to other points. A portion 80 a of the shaft 80 that supports the friction roller 22 and a portion 80 that is supported by the roller support member 83.
It is eccentric with b. The cam 136 has a slope 140, and the link 142 is in contact with this. As a result, the link 142 can be swung by rotating the cam 136. A lower control valve body 144 is attached to the lower surface of the upper control valve body 200 via a separate plate 202, and an oil pan 146 is attached to the casing 67 so as to accommodate the valve body 144, the cam 136 and the like. Lower control valve body 14
4 is provided with a shift control valve 150. Shift control valve 1
Reference numeral 50 denotes a drive rod 154 that is rotationally driven by the speed change motor 152, a sleeve 156, a spool 158 that is fitted in an inner diameter portion of the sleeve 156, and a spool 1.
And a spring 160 for pressing 58 to the right in the figure. The drive rod 154 has a male screw portion 154a at the tip.
Which has an internal thread 156 of the sleeve 156.
It meshes with a. The sleeve 156 has a groove 1 in the axial direction.
56b, and the pin 162 fixed to the lower control valve body 144 is inserted in the groove 156b. This allows the sleeve 156 to move in the axial direction without rotating. An end portion 158a of the spool 158 on the side opposite to the side in contact with the spring 160 is pressed by the above-mentioned link 142 by the force of the spring 160. Spool 158 is land 1
58a and 158b, the opening degree of the ports communicating with the oil passages 166 and 168 can be adjusted. The spool 158 is always in a predetermined axial position with respect to the sleeve 156 in a constant gear ratio state, supplies hydraulic pressure of the same pressure to the oil passages 166 and 168, and the spool 158 is in that position in a gear shift state. The line pressure supplied from the oil passage 164 is distributed to the oil passages 166 and 168. The oil passage 166 is connected to the high side oil chamber 128 on the right side of the drawing through the discharge valve 500 shown in FIG.
Also, it is connected to the low side oil chamber 130 on the left side in the figure. The oil passage 168 is connected to the low side oil chamber 130 on the right side in the figure and the high side oil chamber 128 on the left side in the figure.

FIG. 1 shows a first embodiment of the shift control device.
The shift control device has a shift control valve 150 and a discharge valve 500. The high-side oil chamber 128 is directly connected to the shift control valve 150 by an oil passage 168, and the low-side oil chamber 1
30 is connected to the shift control valve 150 via the discharge valve 500 as described above. The discharge valve 500 has a sleeve 502, a spool 504 fitted in an inner diameter portion of the sleeve 502, and a link 506 capable of moving the spool 504 in the horizontal direction in FIG. 1. Link 50
6, one end of which is slidably fitted in a groove 77b formed on the outer peripheral portion of the cam flange 77 with the fulcrum A as a fulcrum, whereby the axial displacement of the cam flange 77 is detected, The spool 504 can be moved in the left-right direction in FIG. The discharge valve 500 changes the area of the discharge hole 501 and the oil passage 166 according to the movement amount of the spool 504, and the amount of the hydraulic pressure of the low-side oil chamber 130 discharged from the discharge hole 501 and the oil passage from the oil passage 166. The low side hydraulic pressure can be adjusted by adjusting the amount of hydraulic pressure supplied to the chamber 130.

Next, the operation of the first embodiment will be described. When torque is input to the input shaft 14, the friction roller 2
2, the input disk 18 and the output disk 20
A force corresponding to the torque is applied in the rotation direction at the contact portion with. Due to this force, the eccentric shaft 80 that connects the friction roller 22 to the roller support member 83 is deformed. The distance to the cam 136, which is fed back to, changes. That is, the tilt angle of the friction roller 22 and the position of the shift control valve 150 are displaced. Therefore, it tries to stabilize in a state in which the actual gear ratio deviates to the low side from the target gear ratio. That is, a torque shift on the low side occurs. On the other hand, the input shaft 14
The torque input to the cam flange 77 is also input to the cam flange 77, thereby generating thrust in the thrust cam device 400, and pressing the input disk 18 to the right in FIG. As a result, the input disc 18, the output disc 20, the roller support member 83, and the like are deformed, and the thrust cam device 400 moves leftward in FIG. 1 while causing a phase shift to absorb the deformation. Therefore, the link 506 connected to the cam flange 77 of the thrust cam device 400 also swings about the fulcrum A, which causes the spool 504 of the discharge valve 500 to move rightward in FIG. By moving the spool 504, the area of the oil passage 166 can be reduced and the area of the discharge hole 501 can be increased.
It is possible to reduce the hydraulic pressure supplied from 66 to the low side oil chamber 130 and increase the hydraulic pressure of the low side oil chamber 130 discharged from the discharge hole 501. As a result, the oil pressure in the low-side oil chamber 130 can be reduced, so that only the low-side oil pressure is reduced and the differential pressure from the high-side oil pressure is increased, so that an attempt is made to shift to the high side. By these functions,
Since the positional deviation between the friction roller 22 and the cam 136 can be corrected, the torque shift can be corrected as a whole. In addition, even if the torque is the same, the larger the reduction ratio is, the larger the force applied to the roller support member 83 is. Therefore, the deformation amount absorbed by the thrust cam device 400 is also increased. Therefore, the thrust cam device 400 has a larger movement amount as the gear ratio is closer to low. Therefore, since the torque shift amount and the movement amount of the thrust cam device 400 change with the same tendency, the torque shift can be corrected as a whole according to the torque and the gear ratio (that is, the larger the torque and the reduction gear ratio are, the larger the torque shift can be corrected). The correction amount by the discharge valve 500 becomes large).

Next, a second embodiment shown in FIG. 2 will be described. The link 506 connected to the cam flange 77 shown in the first embodiment is removed to remove the low side oil chamber 13
0 is connected to the discharge valve 500 via the differential pressure inspection valve 510, the high side oil chamber 128 is connected to the shift control valve 150 via the differential pressure inspection valve 510, and the differential pressure inspection valve 510 is connected.
, One end of the arm 511 is swingably connected to the fulcrum B, and the other end of the arm 511 is swingably connected to the arm 512.
Of the discharge valve 50 and the other end of the arm 512.
The structure is the same as that of the first embodiment except that it is connected to the spool 0 of 0. The differential pressure inspection valve 510 has a spool 514 that is movable in the left-right direction in FIG. 2 depending on the differential pressure between the low-side hydraulic pressure and the high-side hydraulic pressure. The arm 511 swings about the fulcrum B as a fulcrum in accordance with the displacement amount of the spool 514, whereby the arm 512 moves left and right in FIG. 2 and the spool 504 can move in the axial direction of the sleeve 502. Discharge valve 50 due to movement of spool 504
By changing the areas of the discharge hole 501 and the oil passage 166 of 0,
The oil pressure in the low-side oil chamber 130 discharged from the discharge hole 501 and the oil pressure supplied from the oil passage 166 to the low-side oil chamber 130 can be adjusted to adjust the low-side oil pressure.

Next, the operation of the second embodiment will be described. When torque is input to the input shaft 14, as in the first embodiment, the actual gear ratio stabilizes in a state of being shifted to the lower side than the target gear ratio. By the way, at this time, the high-side hydraulic pressure rises in accordance with the transmission force of the friction roller 22 and the both disks 18 and 20, and becomes higher than the low-side hydraulic pressure. Therefore,
The spool 514 of the differential pressure inspection valve 510 moves leftward in FIG. Therefore, the arm 511 swings around the fulcrum B as a fulcrum, and the arm 512 moves to the right in FIG. Accordingly, the spool 504 of the discharge valve 500
2 moves to the right in FIG. 2, the area of the oil passage 166 can be reduced and the area of the discharge hole of the discharge valve 500 can be increased. Therefore, the hydraulic pressure supplied from the oil passage 166 to the low-side oil chamber 130 is reduced, and the discharge hole 50
It is possible to increase the hydraulic pressure of the low side oil chamber 130 discharged from No. 1. As a result, the oil pressure in the low-side oil chamber 130 can be reduced, so that only the low-side oil pressure is reduced and the differential pressure from the high-side oil pressure is increased, so that an attempt is made to shift to the high side. With this function, the positional deviation between the friction roller 22 and the cam 136 can be corrected, so that the entire torque shift can be corrected.

[0013]

According to the present invention, the differential pressure between the hydraulic pressure in the high-side oil chamber and the hydraulic pressure in the low-side oil chamber is changed in the oil passage that connects the low-side oil chamber of the hydraulic cylinder device and the shift control valve. A discharge valve is provided to allow the hydraulic pressure in the discharge valve to be discharged, and the amount of hydraulic pressure supplied from the oil passage and the hydraulic pressure discharged from the discharge hole can be varied by moving the discharge hole in the discharge valve in the axial direction. A spool is provided, and the spool moves in the axial direction of the thrust cam device in conjunction with the axial movement of the thrust cam device. As a result, even if the torque shift on the low side occurs, the spool of the discharge valve will move as the thrust cam device moves.
Since the oil pressure supplied from the oil passage is reduced and the oil pressure discharged from the discharge hole is increased, the oil pressure in the low-side oil chamber can be reduced. As a result, only the low-side oil pressure is reduced, and the pressure difference with the high-side oil pressure is increased, so that an attempt is made to shift to the high side. Therefore, the torque shift amount is corrected as a whole. Further, even with the same torque, the larger the reduction ratio, the larger the force applied to the eccentric shaft and the roller support member, and therefore the larger the torque shift amount, but the larger the force applied to the roller support member, the larger the deformation amount thereof. Since the amount of movement of the thrust cam device also increases, the amount of movement of the thrust cam device increases as the gear ratio approaches low. As a result, the entire torque shift amount can be corrected according to the magnitude of the torque and the gear ratio. In addition, the spool that is configured to move the spool of the discharge valve in the axial direction by a differential pressure inspection valve that operates according to the differential pressure between the hydraulic pressure in the high-side oil chamber and the hydraulic pressure in the low-side oil chamber The torque shift amount is also changed according to the pressure difference between the oil pressure in the side oil chamber and the oil pressure in the low side oil chamber, but as the pressure difference increases, the pressure difference detection valve increases the oil pressure discharged from the discharge hole by the discharge valve. Since the hydraulic pressure supplied from the oil passage can be reduced as well as the above, the entire torque shift amount can be corrected according to the magnitude of the torque and the gear ratio.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a sectional view of the entire continuously variable transmission.

FIG. 4 is an enlarged view showing a friction wheel type continuously variable transmission.

5 is a sectional view taken along line 5-5 of FIG.

[Explanation of symbols]

 18 Input Disc 20 Output Disc 22 Friction Roller 80 Eccentric Shaft 83 Roller Support Member 83b Rotating Shaft Part 128 High Side Oil Chamber 130 Low Side Oil Chamber 150 Shift Control Valve 166 Oil Path 400 Thrust Cam Device 500 Discharge Valve 501 Discharge Hole 504 Spool

Claims (2)

[Claims] 1. An input disc (18), an output disc (20) and a friction roller (2) arranged in frictional contact with both discs in a toroidal groove formed by both discs.
2) and a thrust cam device (400) which is provided on the rear side of the input disc (18) opposite to the contact surface of the friction roller (22) and generates a thrust corresponding to the input torque on the input disc (18). And a friction roller (22) rotatably supported via an eccentric shaft (80) and rotatable about a rotary shaft portion (83b) orthogonal to the shaft centers of both discs, and the rotary shaft portion (83b). Roller support member (8
3) and a high side oil chamber (128) and a low side oil chamber (130) capable of driving the roller support member (83) to the high side and the low side in the axial direction of the rotating shaft portion (83b), respectively. A hydraulic cylinder device and a shift control valve (15 for controlling the hydraulic pressure of the hydraulic cylinder device).
0), and a shift control device for a friction wheel type continuously variable transmission including: an oil passage (166) that connects the low-side oil chamber (130) of the hydraulic cylinder device and the shift control valve (150).
The oil pressure of the high side oil chamber (128) and the low side oil chamber (1
30) A discharge valve (50) that changes the pressure difference with the oil pressure.
0) is provided, and the discharge valve (500) is provided with a discharge hole (5) capable of discharging the hydraulic pressure in the discharge valve (500).
01) and a spool (504) for varying the hydraulic pressure discharged from the discharge hole (501) and the hydraulic pressure supplied from the oil passage (166) by the movement thereof in the axial direction. (504) is configured to move in the axial direction of the thrust cam device (400) in conjunction with the axial movement of the thrust cam device (400). apparatus. 2. An input disc (18), an output disc (20) and a friction roller (2) arranged in frictional contact with both discs in a toroidal groove formed by the discs.
2) and a friction roller (22) rotatably supported via an eccentric shaft (80) and rotatable about a rotary shaft portion (83b) orthogonal to the shaft centers of both discs, and the above-mentioned rotary shaft portion ( 83b) roller support member (8
3) and a high side oil chamber (128) and a low side oil chamber (130) capable of driving the roller support member (83) to the high side and the low side in the axial direction of the rotating shaft portion (83b), respectively. A hydraulic cylinder device and a shift control valve (15 for controlling the hydraulic pressure of the hydraulic cylinder device).
0), and a shift control device for a friction wheel type continuously variable transmission having: a high side to an oil passage (166) communicating the low side oil chamber (130) of the hydraulic cylinder device and the shift control valve (150). A discharge valve (500) for changing the differential pressure between the oil pressure of the oil chamber (128) and the oil pressure of the low side oil chamber (130) is provided, and the high side oil chamber (128) and the low side oil of the hydraulic cylinder device are provided. A differential pressure detection valve (510) that operates according to the differential pressure of these hydraulic pressures is provided in an oil passage that communicates with the chamber (130). The discharge valve (500) is a discharge valve inside the discharge valve (500). Discharge hole that can discharge hydraulic pressure (5
01) and a differential pressure inspection valve (510) configured to move the valve in the axial direction, and by the axial movement of the valve, the hydraulic pressure and oil passage (501) discharged from the discharge hole (501). A shift control device for a friction wheel type continuously variable transmission, comprising: a spool (504) whose hydraulic pressure supplied from 166) is variable.