JPH10274301A - Toroidal type continuously variable transmission - Google Patents

Abstract

(57) [Summary] In a toroidal type continuously variable transmission, when a solenoid valve constituting a speed ratio control valve is in an electrical failure state, the vehicle travels so as to shift the speed ratio to a speed increasing side. Avoid the dangers of time. SOLUTION: Solenoid valves 65A and 65B are normally-open or normally-closed switching valves, respectively, and control oil pressure PA and PB appearing at SA port and SB port are controlled by a spool valve regardless of which is in an electrical failure state. The 48 sleeve 49 is displaced to the right. The line pressure PL communicates with the B port, and the speed increasing side cylinder chambers 43B, 46 of the hydraulic cylinders 42, 45.
B to the deceleration-side cylinder chambers 43A and 46.
A is set to be larger than the operating oil pressure Pdown for A. The transmission ratio in the toroidal transmission units 1 and 2 shifts to the speed increasing side, and the speed is shifted to the safe side with respect to the traveling of the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input disk having a toroidal curved surface and an output disk, in which a power roller is tiltably disposed, and the rotation of the input disk is steplessly changed and transmitted to the output disk. To a toroidal type continuously variable transmission.

[0002]

2. Description of the Related Art Conventionally, there has been known a toroidal-type continuously variable transmission having a toroidal transmission section composed of an input disk and an output disk disposed opposite to each other, and a power roller in frictional contact with both disks. In this toroidal-type continuously variable transmission, by changing the tilt angle of the power roller, the rotation of the input disk is steplessly changed and transmitted to the output disk.

Some toroidal-type continuously variable transmissions include a plurality of sets of toroidal transmission units arranged on the same shaft. In particular, those in which two sets of toroidal transmission units are juxtaposed are known as a so-called double-cavity toroidal type continuously variable transmission. Also known as a machine. 4 and 5 are views showing an example of a conventional double-cavity toroidal-type continuously variable transmission. FIG. 4 is a schematic view of a conventional double-cavity toroidal continuously variable transmission, and FIG. 5 is a transmission ratio control mechanism of the double-cavity toroidal continuously variable transmission shown in FIG. FIG. FIG.
6 is a flowchart showing a procedure for determining a duty of a solenoid valve in the speed ratio control mechanism shown in FIG.

In the double-cavity toroidal type continuously variable transmission shown in FIG. 4, two sets of toroidal transmission sections 1 and 2 are arranged on a main shaft 3 side by side. The toroidal transmission unit 1 is provided with an input disk 4, an output disk 5 opposed to the input disk 4, and a toroidal frictional surface disposed between the input disk 4 and the output disk 5. The power rollers 6 are combined. Similarly to the toroidal transmission unit 1, the toroidal transmission unit 2 also includes an input disk 7, an output disk 8 disposed opposite the input disk 7, and an input disk 7 and an output disk 8 disposed between the input disk 7 and the output disk 8. 8 comprises a power roller 9 frictionally engaged with the toroidal curved surface. Each of the toroidal transmission units 1 and 2 is provided with two power rollers 6 and 9 respectively. Each of the power rollers 6 and 9 is rotatable about its own rotation axis 10 and is capable of tilting movement about a tilt axis 11 (perpendicular to the paper surface) orthogonal to the rotation axis 10.

In the toroidal transmission units 1 and 2, the input disks 4 and 7 can be displaced in the axial direction of the main shaft 3 and can rotate integrally with the main shaft 3. Power from the engine is input via a torque converter 12 to an input shaft 13 disposed on the same axis as the main shaft 3. A loading cam 14 having a cam roller 15 is provided at the tip of the input shaft 13. The rotation of the loading cam 14 rotates the input disk 4 and further the input disk 7 via the main shaft 3. Therefore, the main shaft 3 is connected to the input disks 4,
7 functions as an input shaft. Further, a thrust force (axial force of the main shaft 3) for pressing the input disks 4, 7 against the power rollers 6, 9 is generated according to the magnitude of the input torque by the cam action of the loading cam 14. The thrust force pinches the power rollers 6, 9 between the input disks 4, 7 and the output disks 5, 8 according to the magnitude of the transmission torque. The rotation of the input disks 4, 7 is transmitted to the output disks 5, 8 via the power rollers 6, 9 based on the shearing force of the oil.

In each of the toroidal transmissions 1 and 2, the power rollers 6 and 9 can be tilted around a tilt shaft 11,
The rotation of the input disks 4 and 7 is transmitted to the output disks 5 and 8 steplessly according to the tilt angle of the power rollers 6 and 9. Power rollers 6 and 9 are trunnions 33 and 3
7 (see FIG. 5) so as to be rotatable and swingable, and can cope with the axial displacement of the main shaft 3 caused by the thrust force.

The output disks 5 and 8 have their back surfaces connected to a connecting shaft 16 by spline fitting or the like so that they can rotate integrally. The connection shaft 16 is a hollow shaft rotatably fitted to the main shaft 3, and a sprocket 18 is integrally formed at an intermediate portion of the hollow shaft. Also, the connecting shaft 16
Is connected to the output shaft 26 as described later. The output disks 5 and 8 are supported by a casing 19 by bearings (not shown) that support loads in the thrust direction and the radial direction via the connection shaft 16. The power transmitted to the output disks 5 and 8 is transmitted from a chain transmission device 17 as a first transmission means, that is, from a sprocket 18 through a chain 20 and an intermediate sprocket 21 to a counter shaft 22 to which the intermediate sprocket 21 is attached at one end. Is taken out.

A forward clutch 23 is provided at the other end of the counter shaft 22. The output side of the forward clutch 23 is connected to a first gear 24, and the first gear 24
A second gear 25 mounted on the output shaft 26 of the entire transmission meshes with the transmission. Therefore, the forward clutch 23 can switch the counter shaft 22 and the first gear 24 to the idling state or the torque transmitting state. The first gear 24 and the second gear 25 serve as reverse rotation transmission means for transmitting the rotation of the counter shaft 22 to the output shaft 26 in the reverse direction. From the chain transmission 17 as the first transmission means, the counter shaft 2
2, a first gear 24 and a second gear 25 as second transmission means
The above mechanism constitutes a reversing mechanism for reversing the rotation of the output disks 5, 8 and transmitting the rotation to the output shaft 26.

A planetary gear mechanism 27 is disposed between the main shaft 3 and the output shaft 26. The planetary gear mechanism 27 includes a sun gear 28 connected to the main shaft 3, a pinion 30 meshing with the sun gear 28 and having a carrier 29, and a ring gear 31 meshing with the pinion 30 and connected to the output shaft 26. Carrier 29 and casing 19
A reverse clutch 32 for switching the carrier 29 to the idling state or the fixed state with respect to the casing 19 is incorporated between them.

Next, the toroidal transmission units 1 and 2 and their shift control will be described with reference to FIGS. The power rollers 6 and 9 are rotatable shafts 34 and 3 respectively.
8 rotatably supported by the trunnions 33 and 37. The trunnions 33 and 37 have the tilt shaft 11, move in the axial direction of the tilt shaft 11 with respect to the casing 19, and can rotate about the tilt shaft 11. That is, when the power rollers 6, 9 are tilted, the tilt angle displacement amount θ of the power rollers 6, 9 is directly changed to the tilt axis 11 of the trunnions 33, 37.
Is the rotational displacement centered at the center.

The input disks 4, 7 and the output disks 5,
Numeral 8 causes elastic deformation in the axial direction of the main shaft 3 due to thrust. The reference of the axial position of the toroidal transmission units 1 and 2 is determined by the casing 19 in which the output disks 5 and 8 are supported by bearings (not shown). 3 in the axial direction. The rotating shafts 34 and 38 for rotatably supporting the power rollers 6 and 9 on the ends 36 and 40 are provided with trunnions 3.
Since the eccentric shaft is eccentric with respect to the swing shafts 35, 39 rotatably supported by the power rollers 3, 37, the displacement of the power rollers 6, 9 in the axial direction of the main shaft 3 is limited by the power rollers 6, 3.
9 is absorbed by the swing motion around the pivot shafts 35 and 39. When the position of the output disks 5, 8 in the thrust direction is determined with respect to the casing 19, the positions of the power rollers 6, 9 are determined, and further, the positions of the input disks 4, 7 in the thrust direction are determined.

The structures of the hydraulic cylinders 42, 45 for displacing the trunnions 33, 37 in the tilt axis direction are basically the same for the trunnions 33 and 37, and the same components are denoted by the same reference numerals. is there. The pistons 41, 41 are respectively attached to the tilt shafts 11 of the trunnions 33, 37.
44 is provided, and the piston 41 is slidably provided in a hydraulic cylinder 42 formed in the casing 19. In the hydraulic cylinder 42, a deceleration-side cylinder chamber 43A and a speed-increasing cylinder chamber 43B defined by the piston 41 are formed. When a pressure difference is generated between the deceleration side cylinder chamber 43A and the speed increasing side cylinder chamber 43B of the hydraulic cylinder 42, the trunnions 33 and 37 move in the tilt axis direction together with the power roller 6. When hydraulic pressure is supplied to the speed increasing cylinder chamber 43B, the speed is shifted to the speed increasing side, and when hydraulic pressure is supplied to the speed decreasing side cylinder chamber 43A, the speed is shifted to the speed decreasing side. The oil passages 47A and 47B are also communicated with the hydraulic cylinder 45 having the corresponding deceleration-side cylinder chamber 46A, the speed-increase-side cylinder chamber 46B, and the piston 44 in the toroidal transmission unit 2 as in the case of the toroidal transmission unit 1. I have.

A sleeve 49 is slidably provided in the main body (valve case) of the spool valve 48. Sleeve 4
The first springs 50 abutting on both ends of the spring 9 bias the sleeve 49 in a direction for holding the sleeve 49 at the neutral position. A spool 51 is slidably provided in the sleeve 49. The spool 51 is biased rightward in FIG. 5 by a second spring 52 disposed at one end, and the other end of the spool 51 is in contact with a precess cam 53 via a lever 54. Also,
The spool valve 48 has an SA port formed at one end and an SB port formed at the other end. A control oil pressure PA is supplied to the SA port through a solenoid valve 55A, and a control oil pressure PB is sent to the SB port through a solenoid valve 55B. Supplied. The spool valve 48 is provided with a line pressure (hydraulic source).
A port connected to the deceleration side cylinder chamber 43A via the oil passage 47A, a B port connected to the speed increasing side cylinder chamber 43B via the oil passage 47B, and an R port connected to the reservoir. It has a port.

The toroidal-type continuously variable transmission includes various sensors such as a vehicle speed sensor 56 and an accelerator pedal depression amount sensor 57 for detecting the depression amount of an accelerator pedal. Shift information such as the accelerator pedal depression amount Acc is input to the controller 58. The controller 58 outputs a control signal corresponding to the target speed ratio calculated based on the speed change information to the solenoid valves 55A and 55B. Solenoid valve 55
A and 55B are an output port C for outputting control oil pressure PA and PB to the SA port and SB port of the spool valve 48, a drain port D, and a control oil pressure source (pilot oil pressure source) P.
It has a hydraulic pressure source port E communicating with S. The solenoid valves 55A and 55B are the same type of solenoid valve,
In the case shown in the figure, the output port C is a normally-open switching valve that communicates with the hydraulic power source port E when an electrical failure such as disconnection occurs in the solenoid valve. Upon receiving a control signal from the controller 58, the solenoid valves 55A and 55B supply the hydraulic pressure from the control hydraulic pressure source PS to the SA port and the SB port, or release the control hydraulic pressure of the SA port and the SB port to the drain. The sleeve 49 is moved in the axial direction according to the target gear ratio. P on sleeve 49
Communication holes corresponding to the L, R, A, and B ports are formed, and the ports PL,
R is connected to port A or port B.

One trunnion 3 of the toroidal transmission 1
A precess cam 53 is connected to the tip of the tilting shaft 11 of the third unit. One end of a lever 54 pivotally connected to the center portion abuts the precess cam 53, and the other end of the lever 54 is connected to the spool 51 of the spool valve 48. It is in contact with the other end. The precess cam 53 detects the combined displacement amount of the displacement axis direction displacement amount Y of the trunnion 33 and the displacement angle displacement amount θ. The spool 51 of the spool valve 48 moves according to the resultant displacement. Spool valve 48 and solenoid valves 55A, 55B
This means that the hydraulic cylinder 4 receives a control signal related to the target gear ratio from the controller 58 and a signal related to the combined displacement amount from the precess cam 53 in order to control the gear ratio.
The gear ratio control valve for adjusting the hydraulic pressures of 2, 45 is constituted.

In the state where the trunnions 33 and 37 are in the neutral position where the displacement amount Y in the displacement axis direction is zero, the displacement angles of the power rollers 6 and 9 are maintained at that time, and the gear ratio is set at that time. Holds a constant value. That is, in this neutral position, the trunnions 33, 37
7 and the rotational axes 10 of the power rollers 6 and 9 intersect with the rotation center lines of the output disks 5 and 8 in the tilt axis direction. At this position, the power rollers 6, 9 are rotated by a tilt angle displacement amount corresponding to the speed ratio. Also,
The spool 51 moves following the sleeve 49 shifted in accordance with the target gear ratio, and is in a state in which the A port and the B port are closed.

The solenoid valves 55A and 55B can be duty solenoid valves in which the duty ratio of the pulse current for exciting the electromagnetic coil can be changed to change the time ratio of the valve operating position taken by the valve element. As an example of a procedure for determining the duty of each of the solenoid valves 55A and 55B, there is a determination flow shown in FIG. Dut shown in FIG.
According to the procedure for determining y, the vehicle speed v
The accelerator pedal depression amount Acc is detected by the accelerator pedal depression amount sensor 58 (step 1).
0, hereinafter abbreviated as S10).
Duty to excite the solenoids of the solenoid valves 55A and 55B so as to correspond to the target gear ratio determined based on the shift information of the vehicle speed v and the accelerator pedal depression amount Acc.
Is obtained (S11). That is, the solenoid valves 55A, 55A
The duty for B is dutyA and duty, respectively.
If B, dutyA = f (Acc, v) (f represents a function) dutyB = 100% −dutyA. Since the solenoid valves 55A and 55B are the same normally-open type solenoid valves, usually, the entire duty (100%) is distributed between dutyA and dutyB so that a differential pressure is generated between the SA port and the SB port. du
ty is required. Each duty is output to the corresponding solenoid valve 55A, 55B (S12), and then returns to the main routine.

Since the solenoid valves 55A and 55B are excited by duty A and duty B, respectively, the control oil pressure PA and PB supplied from the control oil pressure source PS to the ports SB and SA at both ends of the spool valve 48 through the solenoid valves 55A and 55B. The sleeve 49 moves so that the differential pressure of the first spring 50 balances the spring force of the first spring 50, and the moved position of the sleeve 49 indicates the target gear ratio as described above.

The gear ratio is changed by displacing the trunnions 33, 37 in the axial direction of the tilt shaft 11 from the neutral position. That is, when the target gear ratio is changed during rotation of both disks and the sleeve 49 shifts to another position, a relative movement occurs between the sleeve 49 and the spool 51, and the A port corresponds to the amount of movement. Or B port,
Conduction is made to the PL port communicating with the line pressure, and the trunnions 33 and 37 are displaced in the tilt axis direction. Trunnion 33,
The power rollers 6, 9 are also displaced in the tilt axis direction according to the displacement of the 37 in the tilt axis direction, and the contact positions of the power rollers 6, 9 with the input disks 4, 7 and the output disks 5, 8 are set to the neutral positions. Displace from the contact position at the position. As a result, the power rollers 6, 9 receive the tilting force from both disks, and the power rollers 6, 9 are displaced in the displacement direction (that is, the direction of Y> 0 or Y <0) along the tilt axis 11. Amount (absolute value of Y)
Starts tilting around the tilting axis 11 in a direction and at a speed according to. By changing the contact point between the two disks and the power roller, a continuously variable transmission is performed.

On the other hand, the displacement Y in the tilt axis direction of the trunnions 33 and 37 detected by the precess cam 53 and the displacement angle
Is combined with the spool valve 48 via the lever 54.
Of the spool 51 against the spring force of the second spring 52 acting on one end of the spool 51.
To move. Therefore, depending on the relationship between the position of the sleeve 49 given as the target gear ratio and the position of the spool 51 given by the precess cam 53, the oil passage 4
By switching A port and B port connected to 7A and 47B to PL port or R port,
Connect A, 47B to PL port or R port and
The operating oil pressure Pdown and the operating oil pressure Pu of the oil passage 47A of the 7B
A differential pressure is created between the pressure difference p and p. The trunnions 33, 37 in the toroidal transmission unit 1 are displaced in the tilt axis direction due to the pressure difference between the respective operating oil pressures of the cylinder chambers 43A, 43B, and start the shifting operation. When the tilt angle approaches the target tilt angle and the tilt axial displacement amount Y of each of the trunnions 33 and 37 approaches zero, the position of the spool 49 corresponding to the target speed ratio given by the precess cam 53 becomes The vehicle approaches the position, gradually converges, and the shift operation ends.

As described above, the tilt angle control of the power rollers 6 and 9 is performed such that the spool 51 follows the sleeve 49 occupying a position corresponding to the target gear ratio set by the controller 58. Until the follow-up of the spool 51 is completed, the operating oil pressure to the hydraulic cylinders 42 and 45 is controlled through the opened ports, and the trunnion 3 is controlled.
3, 37 are displaced in the tilt axis direction. Trunnion 33,
When the tilting axial displacement Y of the roller 37 becomes zero and the power rollers 6 and 9 are tilted to the target tilting angles, the state where the spool 51 follows the sleeve 49 is completed at that time.

Further, as a toroidal type continuously variable transmission, a trunnion supporting the power roller is not displaced even if the power roller receives a tangential force from an input disk and an output disk during torque transmission (Japanese Unexamined Patent Publication No. -151
No. 218). This toroidal type continuously variable transmission maintains the neutral position of the trunnion by generating a pressure difference in the two cylinder chambers for controlling the displacement of the trunnion in the tilting axial direction, which offsets the tangential force acting on the power roller. ,
The shift is not started again after the shift is completed.

[0023]

The above-mentioned prior arts have the following problems. That is, in the conventional toroidal-type continuously variable transmission illustrated as an example in FIGS. 4 and 5, the control hydraulic pressures PA and PB that act on both ends of the sleeve 49.
Are normally open (normally open type) duty solenoid valves,
That is, when there is no control signal from the controller 58, the pressure of the hydraulic power source PS appears at the output port C of the solenoid valves 55A and 55B. By the way, it is difficult to completely avoid the electrical failure of the solenoid valves 55A and 55B, and the most likely electrical failure is a broken wire.

When an electrical failure occurs in the solenoid valve 55A, the control oil pressure PA appearing at the SA port of the spool valve 48 becomes the pressure of the control oil pressure source PS and becomes larger than the control oil pressure PB appearing at the SB port. (PA ≧ PB). Therefore, the sleeve 49 is pushed rightward in FIG. 5, and the hydraulic pressure applied to the hydraulic cylinders 42 and 45 has a relation of Pup ≧ Pdown, and the trunnion is displaced to the speed increasing side. On the other hand, if an electrical failure occurs in the solenoid valve 55B, SB
The control oil pressure PB appearing at the port becomes the pressure of the control oil pressure source PS and becomes larger than the control oil pressure PA appearing at the SA port (PA ≦ PB). Therefore, the hydraulic cylinders 42, 45
, The working oil pressure becomes Pup ≦ Pdown, and the trunnion is displaced to the deceleration side. And the solenoid valve 55A,
55B, the spool valve 4
Both the SA port and the SB port 9 are at the pressure of the control hydraulic pressure source PS, the sleeve 49 is fixed at the center position, and the speed ratio is a maximum speed reduction ratio and an intermediate speed ratio at the time of maximum speed increase. If the solenoid valve 55B is disconnected among such electrical failures, the toroidal type continuously variable transmission will suddenly shift down, causing an overrun of the engine, a spinning of the vehicle, and the like, causing a dangerous situation. There is a problem that becomes.

Therefore, even if an electrical failure occurs in the solenoid valve, the shifting operation of the toroidal transmission portion is not performed on the deceleration side to avoid a sudden downshift of the toroidal type continuously variable transmission. There are issues to be solved.

[0026]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an electric loss to one or both of two solenoid valves for controlling the position of a sleeve constituting a speed ratio control valve. Even if a fall occurs, the control oil pressure output to the spool valve by the solenoid valve in which the electric failure has occurred is set to a control oil pressure such that the displacement in the tilt axis direction of the trunnion is not set as the displacement on the deceleration side, An object of the present invention is to provide a toroidal type continuously variable transmission which avoids a sudden downshift of the toroidal type continuously variable transmission and prevents a dangerous situation such as engine overrun or vehicle spin from occurring.

According to the present invention, there is provided an input disk and an output disk which are disposed opposite to each other, and wherein the rotation of the input disk is steplessly changed according to a tilt angle with respect to the both disks. A power roller transmitting to an output disk, a trunnion rotatably supporting the power roller and displaceable in a tilt axis direction, a hydraulic cylinder having a cylinder chamber for displacing each trunnion in the tilt axis direction, and the trunnion. Detecting means for detecting a combined displacement of the trunnion displacement in the axial direction of the trunnion and a displacement angular displacement of the power roller; and a target gear ratio and the combined displacement for controlling a gear ratio. And a gear ratio control valve for controlling the operating oil pressure to the cylinder chamber based on the operating oil pressure to the cylinder chamber. And a solenoid valve for outputting control oil pressure for operating the spool valve. The solenoid valve outputs the operating oil pressure from the spool valve when the solenoid valve is in an electrical failure state. The present invention relates to a toroidal-type continuously variable transmission that outputs the control oil pressure so as to shift the ratio to a speed increasing side.

The toroidal type continuously variable transmission according to the present invention is configured as described above, and operates as follows. That is, when the solenoid valve is in an electrical failure state such as disconnection, the control oil pressure output by the solenoid valve is a control oil pressure that outputs an operating oil pressure that causes the spool valve to shift the gear ratio to the speed increasing side. The operating oil pressure output by the spool valve does not displace the trunnion in a direction in which the gear ratio is reduced. Therefore, even when the vehicle is running at high speed, the toroidal type continuously variable transmission does not cause a sudden downshift. Even if the toroidal-type continuously variable transmission causes an upshift, the load torque is increased for the engine, so that it is safe for the running of the vehicle.

In the toroidal-type continuously variable transmission, control oil pressure output from a pair of solenoid valves is supplied to each end of the spool valve, and one of the solenoid valves is a normally-open solenoid valve. The other solenoid valve is a normally closed solenoid valve. According to this toroidal-type continuously variable transmission, since the type of the pair of solenoid valves is different between the normally open type and the normally closed type, even if either solenoid valve is in an electrical failure state, both solenoid valves are spool valves. And the operation of the spool valve is the same as a result, and the operating oil pressure output by the spool valve does not displace the trunnion in the direction in which the speed ratio decreases.

In the toroidal-type continuously variable transmission, the solenoid valve is a duty solenoid valve whose control oil pressure can be changed based on the duty signal, and the duty signals input to both solenoid valves are equal. . By making the solenoid valve a duty solenoid valve, for example, based on the duty ratio of the pulse current that excites the electromagnetic coil, for example, the time ratio at which the output of the solenoid valve communicates with the hydraulic pressure source and the drain is controlled, and the average appearing in the output is controlled. The control oil pressure as an appropriate pressure is changed. According to this toroidal type continuously variable transmission, since the type of the pair of solenoid valves is different between the normally open type and the normally closed type, each solenoid valve outputs by equalizing the duty signals input to both solenoid valves. The control oil pressure has a complementary value that distributes the whole to each other, and is suitable for controlling the spool valve.

In the toroidal-type continuously variable transmission, the spool valve is provided inside the sleeve for controlling the operating oil pressure according to the relative position of the sleeve and the sleeve slidably fitted in the valve body. It has a spool slidably fitted, one of the spool and the sleeve moves in accordance with the resultant displacement, and the other of the spool and the sleeve receives the control hydraulic pressure output by the solenoid valve based on the target gear ratio. Consisting of moving accordingly. When a spool valve of the type having such a sleeve and a spool is used, one of the sleeve and the spool moves so as to correspond to the target gear ratio, and the other moves so as to follow the movement corresponding to the target gear ratio. Shift control is performed.

In the toroidal-type continuously variable transmission, the detecting means for detecting the combined displacement is a precess cam, and one of the spool and the sleeve moves according to the combined displacement by engaging with the precess cam. Become. The precess cam can detect a combined displacement amount of the displacement axial displacement and the displacement angular displacement. When one of the spool and the sleeve is engaged with the precess cam, the combined displacement detected by the precess cam is converted into the movement of one of the spool and the sleeve.

Further, in the toroidal type continuously variable transmission, the spool valve has a spool slidably provided in the valve body for controlling the operating oil pressure according to the position in the valve body. The solenoid valve moves according to the control oil pressure output based on the combined displacement amount and the target gear ratio. If a spool valve having a spool but not having a sleeve is used, for example, the controller outputs a control signal obtained based on the combined displacement amount and the target gear ratio to the solenoid valve, and the solenoid valve controls the control. The control oil pressure corresponding to the signal is output to the spool valve. The spool valve supplies the working oil pressure to the hydraulic cylinder based on the control oil pressure to control the displacement amount of the trunnion in the tilt axis direction.

In the toroidal-type continuously variable transmission, the detecting means for detecting the combined displacement is a precess cam, and the control oil pressure is a voltage value obtained by converting the combined displacement by a potentiometer and a target voltage value corresponding to the target gear ratio. Is output according to the deviation from. The precess cam can detect a combined displacement amount of the displacement axial displacement and the displacement angular displacement. The detected combined displacement and the target gear ratio are respectively converted into voltage values, and the solenoid valve outputs a control oil pressure according to a deviation between these voltage values.

Further, in the toroidal type continuously variable transmission, a pair of power rollers is provided, and a pair of trunnions and hydraulic cylinders are provided corresponding to the power rollers. It is preferable that the toroidal transmission unit has a pair of power rollers in terms of mechanical balance. It is apparent that the present invention is applicable to a double-cavity toroidal-type continuously variable transmission in which the toroidal transmission units having such a configuration are juxtaposed on the same shaft.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a toroidal type continuously variable transmission according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a toroidal type continuously variable transmission according to the present invention. The basic structure of the toroidal type continuously variable transmission shown in FIG. 1 is the same as that of the conventional toroidal type continuously variable transmission shown in FIG. 5 except for the type of the solenoid valve. The same components are denoted by the same reference numerals, and the description of those structures and the basic operation of controlling the gear ratio based on the same structures will not be repeated.

In the toroidal type continuously variable transmission shown in FIG. 1, the solenoid valve 65A is a normally open (normally open) duty solenoid valve, and the solenoid valve 65B is a normally closed (normally closed) duty solenoid. It is a valve. When an electrical failure such as disconnection of the solenoid valve 65A occurs, the output port C communicates with the hydraulic pressure source port E, and the control hydraulic pressure of the control hydraulic pressure source PS acts on the SA port of the spool valve 48. . At this time, assuming that no electrical failure has occurred in the solenoid valve 65B, the control oil pressure PA appearing at the SA port becomes higher than the control oil pressure PB appearing at the SB port (PA ≧ P
B), the sleeve 49 moves to the right in FIG.
The PL port communicates with the B port, and the line pressure
B and 47B are supplied to the pressure-increase cylinder chambers 43B and 46B. Therefore, the magnitude relationship of the operating oil pressure is Pup
.Gtoreq.Pdown, and the displacement of the trunnions 33, 37 in the tilt axis direction is a direction in which the speed ratio is changed to the speed increasing side.

When an electrical failure such as disconnection occurs in the solenoid valve 65B, the output port C communicates with the drain port D, and the control oil pressure appearing at the SB port of the spool valve 48 is released to the drain. Hydraulic pressure. At this time, assuming that no electrical failure has occurred in the solenoid valve 65A, the control oil pressure PA appearing at the SA port is equal to SB as in the case where the electrical failure has occurred in the solenoid valve 65A.
It becomes higher than the control oil pressure PB that appears at the port. Since the sleeve 49 moves to the right in FIG. 1, the magnitude relationship of the operating oil pressure is in a relationship of Pup ≧ Pdown, and the displacement of the trunnions 33, 37 in the tilt axis direction is in the direction of changing the speed ratio to the speed increasing side. .

The solenoid valve 65A and the solenoid valve 65B
If an electrical failure occurs at the same time, the solenoid valve 6
Since the output port C of 5A communicates with the hydraulic pressure source port E and the output port C of the solenoid valve 65B communicates with the drain port D, the control hydraulic pressure PA appearing at the SA port of the spool valve 48 is equal to the pressure of the control hydraulic pressure source PS. And the control oil pressure PB appearing at the SB port becomes the oil pressure released to the drain. Therefore, the control oil pressure PA at the SA port becomes higher than the control oil pressure PB at the SB port, as in the case where one of the solenoid valves 65A, 65B is in an electrical failure state. Since it moves to the right, the trunnions 33 and 37 shift in a direction to change the gear ratio to the speed increasing side.

As described above, the solenoid valve 65A and the solenoid valve 65B are different from each other in the form of a normally open type and a normally closed type, and a signal (duty signal) from the controller 58 that determines a duty ratio in accordance with a target gear ratio. ), The output ports are opened to the control hydraulic pressure source PS so that the average opening degrees are complementary to each other.
The duty signals for operating A and 65B are defined as the same. That is, as shown in FIG. 3, when the accelerator pedal depression amount Acc and the vehicle speed v are detected (Step 1, abbreviated as S1; the same applies hereinafter), based on these information, the target gear ratio is determined. Du of solenoid valve 65A
tyA is determined by a function f of the accelerator pedal depression amount Acc and the vehicle speed v, and dutyB of the solenoid valve 65B is made equal to dutyA (S2). Each dutyA found
And dutyB are respectively assigned to the corresponding solenoid valves 65.
A, 65B (S3).

Next, another embodiment of the toroidal type continuously variable transmission according to the present invention will be described. FIG. 2 is a sectional view showing another embodiment of the toroidal type continuously variable transmission according to the present invention. The toroidal type continuously variable transmission shown in FIG. 2 is an example in which the spool valve 68 constituting the speed ratio control valve is of a type having no sleeve. Therefore, the outputs of the solenoid valves 75A and 75B act directly on the end of the spool 69 of the spool valve 68. The combined displacement amount of the displacement axis direction displacement amount Y and the displacement angle displacement amount θ of the trunnion 33 detected by the precess cam 53 is input to the potentiometer 72 via the lever 71. Potentiometer 72 is
The resultant displacement is converted into a corresponding voltage value V and input to the controller 73. On the other hand, the controller 73 obtains a target gear ratio based on the vehicle speed v and the shift information of the accelerator pedal depression amount Acc input from the vehicle speed sensor 56 and the accelerator pedal depression amount sensor 57, and obtains a target voltage value corresponding to the target gear ratio. V ₀ is obtained by means such as a predetermined conversion table. The controller 73 calculates the voltage value V
A control signal is output to the solenoid valves 75A and 75B in the form of a signal (duty signal) in which the duty ratio is sequentially changed based on the deviation V _e between the duty ratio and the target voltage value V ₀ .

From the output ports C of the solenoid valves 75A and 75B, control oil pressures PA and PB corresponding to each duty are output to the SA port and the SB port of the spool valve 68.
Control oil pressure PA supplied to SA port and SB port,
The PB is controlled so that the pressure difference between the two oil pressures is proportional to the difference V _e between the voltage values. The spool 69 moves left and right in FIG. 2 according to the differential pressure, the PL port communicates with the A port or the B port, and connects the oil passages 47A and 47B to the PL port or the R port to connect the oil passage 47B to the oil passage. Operating pressure of 47A Pd
A differential pressure is generated between own and Pup. Trunnion 3
3, 37 are the differential pressures between the cylinder chambers 42A, 42B in the hydraulic cylinders 42, 45 and the cylinder chambers 45A, 45
The shift operation is started by displacing in the tilt axis direction in accordance with the differential pressure between B and B.

When the tilt angle θ approaches the target tilt angle, the voltage value V
Approaching the target voltage value V ₀ , each trunnion 3
The displacement amount Y in the tilt axis direction of 3, 37 approaches zero, and the actual speed ratio also approaches the target speed ratio. Each time the sign of the deviation V _e of the voltage reverses, by repeating the above shift operation, when the actual gear ratio matches the target gear ratio, tilt axis direction displacement amount of the trunnion 33, 37 Y and variance V _e Are both zero, the power rollers 6, 9 return to the neutral position, and the speed change operation ends.

The solenoid valve 75A is a normally-closed solenoid valve, and when an electric failure such as disconnection occurs,
The output port C communicates with the drain port D and the spool valve 6
The control oil pressure PA of the SA port 8 is released. Assuming that the solenoid valve 75B does not cause electrical failure, the control oil pressure PA becomes lower than the control oil pressure PB acting on the SB port (PA ≦ PB), and the spool 69 of the spool valve 68 moves to the left in FIG. Then, the PL port communicates with the B port, and the line pressure acts on the speed increasing cylinder chambers 43B, 46B of the hydraulic cylinders 42, 45 via the oil passage 47B as the operating oil pressure. As a result, the trunnions 33 and 37 shift to the speed increasing side.

The solenoid valve 75B is a normally open solenoid valve, and when an electrical failure such as disconnection occurs, the output port C is connected to the hydraulic power source port E to control the spool valve 68 to the SB port. The oil pressure PB is set as the pressure of the control oil pressure source PS. Even if the solenoid valve 75A does not cause electrical failure, the control oil pressure PB acting on the SB port becomes higher than the control oil pressure PA (PA ≦ PB), and the spool valve 68
2 also moves to the left in FIG. 2, the PL port communicates with the B port, and the line pressure acts on the speed-increasing cylinder chambers 43B and 46B of the hydraulic cylinders 42 and 45 via the oil passage 47B as operating hydraulic pressure. . As a result, trunnion 3
3, 37 shift to the speed increasing side.

Assuming that the solenoid valves 75A and 75B are simultaneously in an electrical failure state, the control oil pressure PA of the SA port of the spool valve 68 is released, and the control oil pressure PB of the SB port becomes the pressure of the control oil pressure source PS. . Therefore, S
The control oil pressure PB acting on the B port becomes higher than the control oil pressure PA (PA ≦ PB), and the above-described solenoid valves 75A, 75A,
The trunnions 33 and 37 shift to the speed increasing side in the same manner as in the case where any one of 75B is in the electrical failure state. In addition, duty to the solenoid valves 75A and 75B
As shown in FIG. 3, since the types of both solenoid valves are different from each other, the same duty is calculated.

[0047]

The toroidal type continuously variable transmission according to the present invention has the following effects because it is configured as described above. That is, when the solenoid valve is in an electrical failure state such as disconnection, the control oil pressure output by the solenoid valve is:
Since the spool valve is a control oil pressure that outputs an operating oil pressure that shifts the gear ratio to the speed increasing side, the trunnion does not displace in a direction to reduce the gear ratio. Therefore,
If the vehicle is running at a high speed, a sudden downshift of the toroidal type continuously variable transmission, which would make the vehicle run dangerous, does not occur. Even if the toroidal type continuously variable transmission causes an upshift, the load torque is increased for the engine, and therefore, it is safe for the traveling vehicle.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a toroidal type continuously variable transmission according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the toroidal type continuously variable transmission according to the present invention.

FIG. 3 is a flowchart for determining the duty of a solenoid valve applied to the toroidal type continuously variable transmission shown in FIGS. 1 and 2;

FIG. 4 is a schematic view of a conventional toroidal type continuously variable transmission.

FIG. 5 is a cross-sectional view of the conventional toroidal-type continuously variable transmission shown in FIG.

FIG. 6 is a flowchart for determining the duty of a solenoid valve applied to a conventional toroidal-type continuously variable transmission.

[Explanation of symbols]

 1, 2 Toroidal transmission unit 3 Main shaft 4, 7 Input disk 5, 8 Output disk 6, 9 Power roller 11 Tilt shaft 13 Input shaft 16 Connection shaft 19 Casing 26 Output shaft 33, 37 Trunnion 42, 45 Hydraulic cylinder 42A, 42B , 46A, 46B Cylinder chamber 48, 68 Spool valve 49 Sleeve 51 Spool 53 Precess cam (detection means) 58, 73 Controller 65A, 65B Solenoid valve 72 Potentiometer 75A, 75B Solenoid valve PA, PB Control hydraulic pressure Pup, Pdown Operating hydraulic pressure

Claims (8)

[Claims] 1. An output disk which is disposed between an input disk, an output disk and a front disk which are disposed to face each other, and continuously varies the rotation of the input disk in accordance with a tilt angle with respect to the both disks. A power roller, a trunnion rotatably supporting the power roller and displaceable in the tilt axis direction, a hydraulic cylinder having a cylinder chamber for displacing each of the trunnions in the tilt axis direction, provided on the trunnion. Detecting means for detecting a combined displacement amount of the displacement axial direction displacement amount of the trunnion and the displacement angle displacement amount of the power roller; and a target gear ratio and the combined displacement amount for controlling a gear ratio. A gear ratio control valve for controlling the working oil pressure to the cylinder chamber based on the speed ratio control valve. The gear ratio control valve outputs the working oil pressure to the cylinder chamber. A solenoid valve that outputs a control oil pressure for operating the spool valve and the spool valve,
The solenoid valve outputs the control oil pressure so that the operating oil pressure output from the spool valve shifts the gear ratio to a speed increasing side in a state where the solenoid valve is in an electrical failure state. Continuously variable transmission. 2. The control hydraulic pressure output by a pair of solenoid valves is supplied to each end of the spool valve in correspondence with one another, one of the solenoid valves is a normally open solenoid valve, and the other is a solenoid valve. 2. The toroidal-type continuously variable transmission according to claim 1, wherein the solenoid valve is the normally-closed solenoid valve. 3. The solenoid valve according to claim 2, wherein the solenoid valve is a duty solenoid valve whose control oil pressure can be changed based on a duty signal, and wherein the duty signals input to the two solenoid valves are equalized. Toroidal type continuously variable transmission. 4. The spool valve is slidably fitted inside the sleeve for controlling the operating oil pressure according to a relative position between the sleeve and a sleeve slidably fitted in the valve body. One of the spool and the sleeve is moved in accordance with the resultant displacement, and the other of the spool and the sleeve is output by the solenoid valve based on the target gear ratio. 4. The toroidal-type continuously variable transmission according to claim 2, wherein the toroidal-type continuously variable transmission moves in response to a hydraulic pressure. 5. The apparatus according to claim 1, wherein said detecting means for detecting said combined displacement is a precess cam, and said one of said spool and said sleeve is moved in accordance with said combined displacement by engaging said precess cam. Item 5. A toroidal-type continuously variable transmission according to item 4. 6. The spool valve has a spool slidably provided in the valve body for controlling the operating oil pressure in accordance with a position in the valve body. The toroidal-type continuously variable transmission according to claim 2, wherein the toroidal-type continuously variable transmission moves based on the control hydraulic pressure output based on a combined displacement amount and the target gear ratio. 7. The detecting means for detecting the combined displacement is a precess cam, and the control oil pressure is determined by a deviation between a voltage value obtained by converting the combined displacement by a potentiometer and a target voltage value corresponding to a target gear ratio. 7. The toroidal-type continuously variable transmission according to claim 6, wherein the transmission is output. 8. The power supply according to claim 1, wherein a pair of the power rollers is provided, and a pair of the trunnion and the hydraulic cylinder are provided corresponding to the power roller. Toroidal type continuously variable transmission.