JP2002276786A - Toroidal cvt control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fail-safe measures superior in cost performance for a toroidal CVT. SOLUTION: This control device comprises a normal condition shift control valve 229 for controlling forward-to-reverse run, an actuator 239 for actuating the valve 229, an abnormal condition fixed shift control valve 237 for controlling forward run only, an abnormal condition fixed shift control valve 238 for controlling reverse run only, a first change valve 215 for connecting gear change hydraulic chambers 111, 112 and a normal condition shift control part U1 or an abnormal condition shift control part U2, a second change valve 212 for connecting the gear change hydraulic chambers 111, 112 and the forward fixed valve 237 or the reverse fixed valve 238, a first solenoid valve 219 for moving the spool of the first change valve 215 and a manual valve 203 for moving the spool of the second change valve 212 with the operation of a driver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of a control device for a toroidal CVT known as a continuously variable transmission mounted on an automobile.

[0002]

2. Description of the Related Art As is well known, toroidal CVT (Co
ntinously Variable Trans
In the case of “mission”, the gear ratio changes steplessly by controlling the tilt angle of the power roller disposed between the input and output disks. The power roller is supported by a trunnion, and the trunnion is displaced in the tilt axis direction, whereby the power roller is tilted by the rotation of both disks. The trunnion is displaced by receiving a shift control hydraulic pressure such as a speed increasing hydraulic pressure or a deceleration hydraulic pressure generated by the shift control valve. For example, by moving a spool or a sleeve of the shift control valve with an actuator such as a step motor, two shift control hydraulic pressures for speed increase and deceleration having different pressures are adjusted. The trunnion is provided with a piston, a speed increasing hydraulic chamber partitioned by the piston, a speed increasing hydraulic chamber in the deceleration hydraulic chamber,
The supply of the deceleration hydraulic pressure causes the trunnion to be displaced toward the speed increasing side or the deceleration side in accordance with the differential pressure between the two control hydraulic pressures.

[0003] Japanese Patent Application Laid-Open No. Hei 8-233093 discloses fail-safe in a case where a failure of an electric system occurs and as a result, the actuator becomes invalid. According to this, during normal operation, the sleeve of the shift control valve is moved by the actuator, whereas when abnormal, the oil pressure is switched by a manual valve in which the spool moves in response to the driver's shift operation to reduce the operating pressure of the sleeve. The sleeve is moved by acting on one end. In particular, the oil passage is switched so that the operating pressure is supplied only when the L range is selected, and the sleeve moves to the deceleration side. If any other D range is selected, no operating pressure is supplied,
The sleeve moves to the speed increasing side by the urging force of the return spring. As a result, even if a failure occurs, an appropriate gear ratio corresponding to the selected range can be obtained. It is said that running stability will be secured without any delay.

[0004]

However, the above technique is
It is assumed that the actuator does not hinder the movement of the sleeve even if the actuator becomes invalid, and therefore, it is possible to move the sleeve by hydraulic pressure or spring urging force even after a failure occurs. Therefore, in a case where the actuator sticks due to foreign matter biting or the like, and as a result, the sticked actuator prevents free movement of the sleeve, the sleeve is configured to be moved by means other than the actuator. However, the above technology cannot be fully utilized. Furthermore, when the sleeve itself sticks and becomes immovable, the above technique is hardly applicable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fail-safe that can sufficiently satisfactorily cope with a failure of a shift control unit including an actuator and a shift control valve. Hereinafter, the present invention will be described in detail including other problems.

[0006]

According to a first aspect of the present invention, there is provided a shift control unit including a shift control valve for generating a shift control hydraulic pressure, and a shift control unit including the shift control hydraulic pressure. A toroidal CVT control device including a shift execution unit for executing a shift, comprising: a normal shift control unit including a single shift control valve for controlling from forward movement to reverse movement; and a forward shift control valve for controlling only forward movement. An abnormal speed shift control unit including a reverse speed change control valve that controls only the reverse direction,
In normal operation, the shift control hydraulic pressure generated by the shift control valve of the normal shift control unit is used, and when abnormal, the shift control hydraulic pressure generated by the shift control valve of the abnormal shift control unit is used. A first switching valve for switching a connection state between the shift control unit and the shift execution unit; and a forward switching unit when the forward shift control unit and the shift execution unit are connected by the first switching valve. A shift control hydraulic pressure generated by the shift control valve is used, and the connection state between each shift control valve and the shift execution unit is switched so that the shift control hydraulic pressure generated by the reverse shift control valve is used during reverse travel. 2 switching valves.

According to the present invention, when there is no failure in normal operation, all shift control from forward to reverse can be executed by using a single normal shift control valve. on the other hand,
In the event of a failure, a shift control can be performed using the shift control valve for the time of the failure. In this case, the forward and backward movement control valves are used for forward movement when moving forward and reverse movement when moving backward. it can.

[0008] In this way, since the vehicle can run sufficiently satisfactorily using the shift control unit for the abnormal state, the shift control unit for the normal state does not need to be used at all in the abnormal state. As a result, no matter what kind of failure occurs in the shift control valve included in the normal-time shift control unit, or what kind of failure occurs in the actuator that operates the shift control valve, or both of them fail. , A sufficiently satisfactory shift control can be ensured without any problem.

By the way, for example, when the geared neutral system is adopted for the continuously variable transmission, the vehicle moves forward or backward at a predetermined gear ratio for realizing geared neutral. Therefore, in order to control everything from forward movement to reverse movement using only a single shift control valve, a precise control operation is required, especially near geared neutral, and such a precise control operation can be executed without any trouble during normal operation. However, it is questionable whether it can be executed without any trouble in abnormal situations.

Therefore, in the present invention, unlike the normal-time shift control unit, the abnormal-time shift control unit is provided with a forward-only shift control valve and a reverse-only shift control valve, respectively. . As a result, even in the event of a failure, reliable forward / backward separation at the geared neutral is guaranteed, and it is possible to stably respond to the driver's traveling demand.

On the other hand, in a normal state where fine control operations can be performed without any trouble, a single shift control valve performs all forward and backward shift controls, so that only one actuator is required. The cost can be significantly reduced as compared with the case where two actuators are provided for forward movement and two actuators.

As described above, according to the present invention, it is possible to take a fail safe which is excellent in cost performance.

According to a second aspect of the present invention, in the first aspect of the present invention, a manual valve for switching an oil passage by operating according to a shift operation of a driver is provided. The switching valve of No. 2 is characterized in that the connection state is switched by operating with the operating pressure supplied by switching the oil passage of the manual valve.

According to the present invention, the second operation is performed by the mechanical movement of the manual valve in conjunction with the driver's shift operation.
The operation pressure is reliably supplied and discharged to and from the switching valve, and when the forward range is selected, the shift valve is switched to the forward shift control valve stably and smoothly when the reverse range is selected.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the forward shift control valve and the reverse shift control valve each include a predetermined shift for realizing forward shift. It is characterized in that it is configured to achieve only a predetermined gear ratio for realizing the ratio or the reverse.

According to the present invention, the forward and reverse shift control valves used in the event of an abnormality are fixed valves, and as a result, no actuator is required for operating the shift control valve. Ability can be achieved at minimal cost.

That is, in order to ensure a sufficient fail-safe even when the normal-time shift control unit becomes unusable,
In the simplest case, two sets of shift control units each having both a shift control valve and an actuator may be mounted for normal use and for abnormal use. However, this increases costs. In addition, as described above, there is another problem as to whether or not the actuator can operate the shift control valve precisely at the time of failure as in the case of normal operation.

Therefore, according to the present invention, the operation by the actuator is not required by using the shift control valve for abnormal time as a fixed valve. As a result, the cost can be reduced, and the achievement of a reliable target gear ratio in the event of a failure can be guaranteed, and, as a result, it is possible to stably respond to the required minimum traveling requirements.

Next, according to a fourth aspect of the present invention, in the invention of any one of the first to third aspects, a low mode in which different final speed ratios are achieved at the same speed ratio when the vehicle is moving forward. And the high mode can be realized.

According to the present invention, even when only one predetermined gear ratio for realizing the forward movement by the forward fixed valve is achieved at the time of forward movement at the time of failure, the switching between the low mode and the high mode causes the failure at the time of failure. Even so, an appropriate final gear ratio corresponding to the operating state can be obtained. As a result, for example, in the low mode, a final reduction ratio on the reduction side that ensures good startability is achieved, and in the high mode, a final transmission on the speed-up side that ensures good running stability without sudden engine braking. It is also possible that the ratio is achieved. Hereinafter, the present invention will be described in more detail through embodiments of the present invention.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Mechanical Structure] As shown in FIG. 1, a toroidal CVT 10 according to the present embodiment includes an input shaft 11 connected to an output shaft 2 of an engine 1 via a torsional damper 3. , A hollow primary shaft 12 loosely fitted to the shaft 11, and a secondary shaft 13 arranged in parallel with the shafts 11, 12. Two toroidal-type continuously variable transmission mechanisms 20 and 20 are provided on the primary shaft 12. Each continuously variable transmission mechanism 20 includes two power rollers 23 for transmitting power between an input disk 21 and an output disk 22 having a toroidal surface. Each input disk 21
Is coupled to an end of the primary shaft 12, and the output disks 22 are integrally formed and rotatably supported at an intermediate portion of the primary shaft 12.

A first gear 31 of the first gear train 30 is provided at an end of the input shaft 11 opposite the engine, and a second gear 32 is rotatably supported at an end of the secondary shaft 13 opposite the engine. Gears 31 and 32 are connected by an idle gear 33. A loading cam mechanism 40 is provided between the first gear 31 and the input disk 21. The second gear train 5 is provided on the outer periphery of the output disks 22 and 22.
0 first gear 51 is provided, and the secondary shaft 13
A second gear 52 is rotatably supported at an intermediate portion of the gears, and these gears 51 and 52 mesh with each other.

A planetary gear mechanism 60 is provided on the secondary shaft 13. A low clutch 70 is provided between the pinion carrier 61 of the planetary gear mechanism 60 and the second gear 32 of the first gear train 30. A high clutch 80 is provided between the sun gear 62 and the secondary shaft 13. Sun gear 62 and second gear 5 of second gear train 50
And 2 are combined. The internal gear 63 and the secondary shaft 13 are connected.

A first gear 4a of the output gear train 4 is provided at an end of the secondary shaft 13 on the engine side, and a second gear 4b is provided in the differential device 5, and these gears 4a and 4b are connected by an idle gear 4c. are doing. Left and right drive wheels (not shown) are provided on drive shafts 6 a and 6 b extending from the differential device 5. An oil pump 90 driven by the first gear 31 of the first gear train 30 is disposed at an end of the input shaft 11 opposite to the engine. The specific structure of the toroidal CVT 10 is shown in FIGS.

[Shift Execution Section] As shown in FIG. 3, each power roller 23 of the continuously variable transmission mechanism 20 is supported by a trunnion 25 via an eccentric shaft 24. The trunnion 25 is a pair of support plates 2 housed in the transmission case 100.
6 and 26 are supported so as to be movable in the horizontal direction and rotatable around the axis of movement. The trunnion 25 has a rod 27 extending in the horizontal direction, and the rod 27 is provided with a speed increasing piston 28 and a speed reducing piston 29.
Each piston 28, 29 is mounted on the side wall 10 of the transmission case 100.
The hydraulic cylinder formed in 1 is defined as a hydraulic chamber for speed increase 111 and a hydraulic chamber for deceleration 112.

The hydraulic chambers 111 and 112 are connected to a speed increasing hydraulic line 223 or a speed reducing hydraulic line 226, and receive a speed increasing hydraulic pressure and a deceleration hydraulic pressure supplied from a shift control unit, which will be described later. 25, and constitutes a shift execution unit that shifts the horizontal direction.

[Hydraulic Control Circuit] As shown in FIG. 4, the hydraulic control circuit 200 of the toroidal CVT 10 has a regulator valve 202 which generates a predetermined line pressure from the discharge pressure of the oil pump 90 and outputs it to the main line 201. Prepare. The main line 201 leads to a manual valve 203 in which a spool moves according to a shift operation by a driver. The manual valve 203 communicates the main line 201 with the low clutch line 204 and the high clutch line 205 in the D range, communicates only with the low clutch line 204 in the R range, and does not communicate with any line in the N range or the P range. .

The low clutch line 204 includes a low clutch duty solenoid valve (DSV) 206 and a third
The low clutch 70 is reached via the fail-safe shift valve (third Sft) 207 and the accumulator 208. The high clutch line 205 reaches the high clutch 80 via a high clutch duty solenoid valve (DSV) 209 and an accumulator 210. Each DSV2
06 and 209 are fully opened at a duty ratio of 0% and fully closed at 100%.

A branch line 211 from the high clutch line 205 is connected to a second fail-safe shift valve (second shift valve).
ft) 212. Main line 201
Branch line 213 leads to, for example, a starting clutch (not shown). A further branch line 214 from the branch line 213 is connected to a first fail-safe shift valve (first Sf
t) 215 is reached.

The hydraulic control circuit 200 includes an oil pump 90
A predetermined operating pressure is generated from the discharge pressure of the
6 is provided with a reducing valve 217 for outputting the same. The operating pressure line 216 reaches a control port of the regulator valve 202 through a line pressure linear solenoid valve (LSV) 218. The operating pressure line 216 is a fail-safe first on / off solenoid valve (first SOL) 2.
Through 19, it reaches the control port of the first Sft 215. Further, the operating pressure line 216 passes through a second fail-safe on / off solenoid valve (second SOL) 220 to form a third Sf
The control port reaches t207. Each SOL 219,22
When 0 is ON, the line is connected, and when OFF, the line is disconnected (downstream drain).

When the spool of the first Sft 215 moves to the left or right, the branch line 214 is connected to the normal input line 221 or the abnormal input line 222, and the speed increasing hydraulic line 223 (see FIG. 3) is connected to the normal speed increasing hydraulic pressure. Line 224
Alternatively, it is connected to the abnormal-time speed increasing hydraulic line 225, and the deceleration hydraulic line 226 (see FIG. 3) is connected to the normal-time deceleration hydraulic line 227 or the abnormal-time deceleration hydraulic line 228. Each normal line 221, 224, 227 leads to a normal-time shift control valve 229, and each abnormal line 222, 22.
5, 228 leads to the second Sft 212. A relief pressure line 230 for supplying an operating pressure lower than the line pressure is connected to the normal speed shift control valve 229.

When the spool of the second Sft 212 moves right and left, the abnormal input line 222 becomes the forward input line 2.
31 or the reverse input line 232, and the abnormal-time speed increasing hydraulic line 225 is connected to the forward speed increasing hydraulic line 233.
Alternatively, it is connected to the speed increasing hydraulic line 234 during reverse movement, and the abnormal speed deceleration hydraulic line 228 is connected to the forward speed reducing hydraulic line 23.
5 or the reverse deceleration hydraulic line 236. Each forward line 231, 233, 235 leads to a forward shift control valve 237, and each reverse line 232, 234, 2.
Reference numeral 36 denotes a reverse speed change control valve 238.

[Shift control unit] The shift control unit has a normal speed shift control unit U1 and an abnormal speed shift control unit U2. The normal shift control unit U1 includes a normal shift control valve 229, and the abnormal shift control unit U2 includes a forward shift control valve 23.
7 and a reverse speed change control valve 238. The normal shift control unit U1 also includes a step motor (SM) 239 as an actuator for moving the spool of the normal shift control valve 229. The link 240 between the rod 240 of the SM 239 and the rod 241 of the spool of the transmission control valve 229
It is connected at 42.

Each of the speed change control valves 229, 237, 238 is provided with a mechanism for feeding back the tilt angle of the power roller 23. The feedback mechanism is, as shown in FIG. 5, one of the four trunnions 25.
And a precess cam 243 mounted on the rods 27 of the two trunnions 25. The cam 243 has a spiral cam surface. A support shaft 244 is rotatably provided on the transmission case 100 or the valve body, and an input lever 245 attached to one end of the support shaft 244 is in contact with the cam surface.

The three output levers 246, 2 are attached to the support shaft 244.
47 and 248 are arranged side by side, of which the output lever 246 for normal operation is connected to the link 242 of the transmission control unit U1 for normal operation, and the output lever 247 for forward operation and the output lever 248 for reverse operation are respectively shifted for abnormal operation. 4 is engaged with the spools of the transmission control valves 237 and 238 of the control unit U2 (FIG. 4).
reference).

[Control Unit] As shown in FIG. 6, the control unit 300 of the toroidal CVT 10 includes an engine speed sensor 301 for detecting the engine speed, and an output disk speed sensor 302 for detecting the speed of the output disk 22. A signal from a vehicle speed sensor 303 (refer to FIG. 1) for detecting a vehicle speed, a throttle opening sensor 304 for detecting a throttle opening, and the like are input, and the low clutch is used in accordance with an operating state determined from these signals. And DSVs 206 and 209 for high clutch, LSV 218 for line pressure, first for fail safe (FS)
And the second SOLs 219 and 220, the normal speed shift control valve SM 239, and the like are controlled to change the speed ratio (toroidal ratio) of the continuously variable transmission mechanisms 20, 20 and thus the toroidal CV.
The final gear ratio (unit ratio) of T10 is controlled.

[Control Operation in Normal State]
219 is turned on, and the spool of the first Sft 215 moves to the left. As a result, the branch line 214 is connected to the normal input line 221, and the line pressure is supplied to the normal shift control valve 229. Further, the speed increasing hydraulic line 223 is connected to the normal speed increasing hydraulic line 224, and the deceleration hydraulic line 226 is connected to the normal speed reducing hydraulic line 227.
That is, the shift control valve 229 of the normal shift control unit U1 is connected to the shift execution units (hydraulic chambers) 111 and 112.

As shown in FIG. 7, the normal speed control valve S
As the number of pulses of the control signal output to M239 increases, the toroidal ratio decreases (speed increase). That is, when the pulse number increases, the rod 240 of the SM 239 advances, and the rod 241 of the spool of the normal-time speed change control valve 229 moves to the right in FIGS. As a result, the normal-time input line 221 and the normal-time speed-increasing hydraulic line 224 communicate with each other to increase the speed-increasing hydraulic pressure supplied to the speed-increasing hydraulic chamber 111, while the relief pressure line 230 and the normal-time decelerating speed line are increased. The deceleration hydraulic pressure supplied to the deceleration hydraulic chamber 112 through communication with the hydraulic line 227 decreases.
Then, in FIG. 3, the upper trunnion 25 is displaced to the right, and the lower trunnion 25 is displaced to the left, receiving the rotation of the output disk 22 rotating in the x direction and the input disk 21 rotating in the anti-x direction. , Upper and lower power rollers 2
Each of the members 3 and 23 is tilted so that the contact position with the input disk 21 moves outward in the radial direction and the contact position with the output disk 22 moves inward in the radial direction, and the toroidal ratio decreases.

When the power roller 23 tilts as described above, the precess cam 243 rotates in the direction a in FIG. 5, and the contact point between the cam surface and the input lever 245 becomes high, and the support shaft rotates in the direction c. Move. As a result, in FIG. 4, the output lever 246 for normal operation swings in the direction e, and the rod 241 of the spool of the shift control valve 229 for normal operation connects the link 242.
Move left through. As a result, the spool of the shift control valve 229 returns to the neutral position, and the shift ends. SM23
The number of pulses of 9 and the tilt angle of the power roller 23, that is, the toroidal ratio basically correspond one to one.

In accordance with this, the SM2 for normal speed shift control valve is used.
When the number of pulses of the control signal output to 39 decreases, the toroidal ratio increases (deceleration). At this time, the precess cam 243 rotates in the direction b, the support shaft rotates in the direction d, and the output lever 246 also oscillates in the direction d, so that the spool of the normal-time shift control valve 229 that first moves to the left moves. Link 2
To the right via the transmission control valve 229.
Is returned to the neutral position, and the shift is completed.

(Geared Neutral) In the non-running range of the N range or the P range, the line pressure is not supplied to the low clutch line 204 and the high clutch line 205 by the manual valve 203 as described above. Therefore, both the low clutch 70 and the high clutch 80 are released, and power is not transmitted from the input shaft 11 side to the secondary shaft 13 side. Only the first gear train 3 on the secondary shaft 13
0, the second gear 32 rotates, and the low clutch 7
The input side rotating member of 0 is rotating. Similarly, the second gear 52 of the second gear train 50 rotates on the secondary shaft 13, and accordingly, the sun gear 62 of the planetary gear mechanism 60, the pinion carrier 61, and the output-side rotating member of the low clutch 70 rotate.

In this state, when the toroidal ratio is controlled to a predetermined gear ratio (GN ratio: Rgn: see FIG. 7), the rotation direction and the rotation speed of the input side rotation member and the output side rotation member of the low clutch 70 match. At this time, if the secondary shaft 13 and the internal gear 63 are not rotating while the vehicle is stopped, a state in which the vehicle does not start moving even if the low clutch 70 is engaged is realized. This is the geared neutral (GN) state.

(Forward Low Mode) When the vehicle is switched to the forward drive range of the D range for starting, the low clutch line 20 is operated by the manual valve 203 as described above.
4 and the high clutch line 205 are supplied with line pressure. In a normal state, the second SOL 220 is turned on, and the spool of the third Sft 207 is moving to the right.
Therefore, the low clutch 70 can be engaged by setting the duty ratio of the low clutch DSV 206 to 0%. On the other hand, the duty ratio of the high clutch DSV 209 is set to 100%, and the high clutch 80 is kept released. As described above, in this GN state, the vehicle has not started yet.

In the GN state, the unit ratio is infinite, as indicated by reference character A in FIG. From here SM239
When the number of pulses of the control signal to be output is reduced, the toroidal ratio increases as described above, and as a result, the rotation speed of the sun gear 62 decreases, and the internal gear 63 starts rotating in the forward direction. As shown by L, the forward low mode in which the unit ratio becomes small is realized. The power from the input shaft 11 is input to the planetary gear mechanism 60 via the first gear train 30, and at the same time, the planetary gear mechanism 60 is also transmitted via the continuously variable transmission mechanisms 20, 20 and the second gear train 50. , And then transmitted to the secondary shaft 13.

(High Mode) When the unit ratio becomes smaller in the forward low mode L, a predetermined switching point is finally reached, as shown by reference numeral A in FIG. Here, the duty ratio of the low clutch DSV 206 is set to 100%.
And at the same time, the high clutch 80 is engaged with the duty ratio of the high clutch DSV 209 set to 0%. The power from the input shaft 11 does not pass through the planetary gear mechanism 60, and the continuously variable transmission mechanism 20,
20, the second gear train 50, and the high clutch 80 are transmitted to the secondary shaft 13. As a result, a high mode in which the unit ratio and the toroidal ratio are proportional to each other is realized, as indicated by reference numeral H in FIG.

The switching point is a point at which the toroidal ratio and the unit ratio match in the low mode L and the high mode H.
The increase / decrease tendency of the number of pulses of the control signal output to the control signal 239 is reversed.

(Reverse low mode) In contrast to the above, when the vehicle is switched to the reverse travel range of the R range in order to start while the vehicle is stopped, the manual valve 203 is operated as described above.
Thus, the line pressure is supplied only to the low clutch line 204. Therefore, the low clutch 70 can be engaged by setting the duty ratio of the low clutch DSV 206 to 0%. The high clutch 80 remains released. Even when the R range is selected, the vehicle does not start yet in the GN state, and the unit ratio is infinitely small as shown by the symbol c in FIG.

When the number of pulses of the control signal output to the SM 239 from the GN state is increased, the toroidal ratio is reduced as described above, and as a result, the rotation speed of the sun gear 62 is increased, and the internal gear 63 is moved in the reverse direction. The reverse low mode in which the rotation starts and the unit ratio becomes large as indicated by the symbol R in FIG. 8 is realized. Power from the input shaft 11 is transmitted to the secondary shaft 13 via the planetary gear mechanism 60 as in the forward low mode L.

(Shift Characteristics) Control Unit 300
Determines the unit ratio based on the shift characteristics shown in FIG. That is, the current vehicle speed and the throttle opening are read from the output signals of the vehicle speed sensor 303 and the throttle opening sensor 304, and are applied to the preset shift characteristics as shown in FIG.
Set eo. And, this target engine speed Ne
According to the characteristics shown in FIG. 8, a unit ratio (represented by an angle α in the figure) realizing o is achieved.
The SM 239 and the DSVs 206 and 209 are controlled.

[Control Operation at the Time of Abnormality] Next, a specific example of the control operation at the time of abnormality will be described with reference to the flowchart shown in FIG.

(Types and Judgments of Abnormalities) First, abnormalities (failures, failures) are roughly classified into abnormalities of the normal-time shift control unit U1 and rotation sensors 301 to 3 necessary for the shift operation.
There are 03 types of abnormalities. The abnormality of the transmission control unit U1 is, for example, the spool or rod 2 of the normal-time transmission control valve 229.
41, a stick of the rod 240 of the SM 239 for the normal speed shift control valve, a break of the SM 239, and the like. In such a case, even if a shift command (a control signal of the pulse number for SM 239) is output, no shift is performed (the toroidal ratio does not change). Therefore, it can be determined that the normal-time shift control unit U1 is abnormal based on the behavior of the toroidal ratio. The toroidal ratio Rt can be obtained from the engine speed Ne and the output disk speed No (Rt = Ne / No).

On the other hand, when an abnormality occurs in the sensors or the like, a phenomenon occurs in which the actual gear ratio greatly deviates from the gear shift command. Originally, an error occurs between the target speed ratio and the actual speed ratio according to the speed change command.However, when the sensors do not correctly sense the rotational speeds of various components on the power transmission path, the actual speed ratio is reduced. The calculation cannot be performed, or the actual gear ratio becomes a random value, and the error becomes larger than an allowable range. Therefore,
When the difference between the target speed ratio and the actual speed ratio is equal to or greater than a predetermined value, it can be determined that the rotation sensors 301 to 303 are abnormal.

(Abnormality of Normal Speed Shift Control Unit U1) <Switching of Connection State> In step S1, various state quantities are detected. If it is determined in step S2 that the normal speed shift control unit U1 is abnormal, step S3 is performed first. To turn off the first SOL 219 and move the spool of the first Sft 215 to the right. As a result, the branch line 214 is connected to the abnormal input line 222, and the line pressure is supplied to the second Sft 212. Also, when the speed increasing hydraulic line 223 is abnormal, the speed increasing hydraulic line 2
25, and the deceleration hydraulic line 226 is connected to the abnormal-time deceleration hydraulic line 228. That is, the connection between the shift control valve 229 of the normal shift control unit U1 and the shift execution units 111 and 112 is disconnected.

When it is determined in step S4 that the vehicle is traveling in the forward low mode L, and when it is determined in step S9 that the vehicle is traveling in the high mode H, D is determined.
Because of the range, the line pressure is supplied to the control port of the second Sft 212 via the branch line 211,
The spool of ft212 has moved to the left. as a result,
The abnormal input line 222 is connected to the forward input line 231, and the line pressure is supplied to the forward shift control valve 237. Further, the speed increasing hydraulic line 225 is connected to the forward speed increasing hydraulic line 233, and the abnormal speed decreasing hydraulic line 2
28 is connected to the forward deceleration hydraulic line 235. That is, the forward speed shift control valve 237 of the abnormal speed shift control unit U2 is connected to the shift execution units 111 and 112.

On the other hand, if the answer is NO in both steps S4 and S9, that is, if it is determined that the vehicle is traveling in the reverse low mode R, the vehicle is in the R range.
No line pressure is supplied to the control port 212 via the branch line 211, and the spool of the second Sft 212 is moving to the right. As a result, the abnormal input line 222 is connected to the reverse input line 232, and the line pressure is supplied to the reverse shift control valve 238. In addition, the abnormal-time speed increasing hydraulic line 225 is connected to the reverse speed increasing hydraulic line 234,
Abnormal deceleration hydraulic line 228 connects to reverse deceleration hydraulic line 236. That is, the reverse speed shift control valve 238 and the shift execution units 111 and 112 are connected to each other.

<Shift Control Valve for Abnormal Time> The forward shift control valve 237 and the reverse shift control valve 238 of the abnormal shift control unit U2 are both fixed valves. That is, the forward valve 2
37 achieves only a predetermined toroidal ratio on the forward side (deceleration side) of the GN, as indicated by a symbol Ra in FIG.
The reverse valve 238 achieves only a predetermined toroidal ratio on the reverse side (increased side) of GN, as indicated by a reference symbol Rb in FIG.

As shown in FIG. 8, the forward fixed ratio Ra is the fixed unit ratio G1 on the deceleration side in the low mode.
In the high mode, the speed is converted to the fixed unit ratio G2 on the speed increasing side. The low mode fixed unit ratio G1 is set to a speed ratio that can ensure a good startability, and is, for example, 5M.
It is assumed that the gear ratio is the first gear of T or the like. The high mode fixed unit ratio G2 is set to a speed ratio that can ensure good running stability without sudden engine braking, and is set to, for example, a speed ratio of about 4 speed of 5MT.

The reverse fixed ratio Rb is converted to a reverse fixed unit ratio G3, as shown in FIG. The reverse fixed unit ratio G3 is set to a speed ratio that can ensure good startability, and is set to, for example, a speed ratio of about Rev of the MT.

In step S3, the first SOL 219 is turned off. As a result, when the shift control from the normal-time shift control valve 229 is switched to the shift control by the abnormal-time shift control valve 237 or 238, In most cases, the spools of the fixed valves 237 and 238 except for the case that the speed ratio of the fixed valves 237 and 238 coincide with the fixed speed ratio Ra (G1), Ra (G2) or Rb (G3). It is not at the neutral position as shown in FIG.

As a result, for example, in the case of the forward fixed valve 237, the line pressure is increased by the speed increasing hydraulic lines 233, 225, 22
3, the trunnion 25 is displaced by being supplied to the speed-increasing hydraulic chamber 111 via the deceleration hydraulic lines 112, 235, 228 and 226. The power roller 23 tilts to the speed increasing side or the speed decreasing side. Similarly, in the case of the reverse fixed valve 238, the line pressure is supplied to the speed-increasing hydraulic chamber 111 via the speed-increasing hydraulic lines 234, 225, and 223, or the deceleration hydraulic lines 236, 228, and 226. , The trunnion 25 is displaced, and the power roller 23 tilts to the speed increasing side or the speed decreasing side.

In each case, the fixed speed ratio Ra
When (G1), Ra (G2) or Rb (G3) is achieved, the forward fixed output valve 247 or the abnormal reverse output lever 248 swings to cause the fixed forward valve 2 to rotate.
37 or the spool of the reverse fixed valve 238 returns to the neutral position, and the shift is completed.

<In the case of D range> Step S5 is a routine to be performed first even in the case of the D range, particularly when a failure occurs during traveling in the forward low mode L. That is, the low clutch 70 is released and the high clutch 80 is engaged. Thereby, even if the gear ratio is fixed to the fixed ratio Ra,
A high-mode fixed unit ratio G2 is achieved instead of the low-mode fixed unit ratio G1, so that abrupt engine braking can be avoided and good running stability can be ensured. In this case, the engagement of the high clutch 80 may be performed only when the vehicle speed is relatively high, and the engagement of the high clutch 80 may not be performed when the vehicle speed is relatively low.
The vehicle speed as a criterion for determining whether or not to engage the high clutch is appropriately determined in relation to the fixed ratio Ra.

As described above, when the low clutch 70 is released and the high clutch 80 is engaged, the duty ratio of the low clutch DSV 206 is reduced from 0% to 100%.
100% duty ratio of DSV209 for high clutch
However, at the same time, the second SOL 220 for FS may be switched from on to off to move the spool of the third Sft 207 to the left. The low clutch line 204 is disconnected at the third Sft 207, and the low clutch 70 is switched to the low clutch DSV2.
Forcibly released irrespective of the operating state of 06.

Next, step S6 is a routine during the period from the occurrence of a failure to the stop. That is, when the normal speed shift control unit U1 fails, the gear ratio is fixed to the fixed ratio Ra, and the GN ratio (Rgn) cannot be achieved. As a result, GN cannot be achieved. Both 70 and 80 are released, but the high clutch 80
And run. The vehicle speed as a criterion for determining whether or not to release the high clutch 80 at this time is also appropriately determined in relation to the fixed ratio Ra. The low clutch 70 remains released.

When a failure occurs during traveling in the high mode L, the low clutch 70 has already been released and the high clutch 80 has been engaged. Therefore, the routine of step S6 may be started from the beginning of the failure. .

Next, step S7 is a routine for restarting in the D range. That is, when the vehicle restarts, the vehicle starts with the low clutch 70. However, since the speed ratio is the fixed ratio Ra (G1), the duty ratio of the low clutch DSV 206 is controlled to prevent engine stall by controlling the low clutch 70. Start while sliding. When the vehicle speed becomes equal to or higher than a predetermined vehicle speed, the low clutch 70 is completely engaged.
Switch to. At this time, the vehicle speed when the low clutch 70 is completely engaged and the vehicle speed when the clutches 70 and 80 are switched are also appropriately determined in relation to the fixed ratio Ra. DSV 206, 209 corresponding to the vehicle speed used at the time of restart
May be stored in a memory in advance. Next, in step S8, a warning is issued, and a method of notifying that the failure has occurred is intended.

<In the case of R range>
This is the first routine to be performed if a failure occurs during reverse travel in the range. That is, when the vehicle speed is high, the low clutch 70 is released to prevent the engine 1 from over rotating. Further, the overspeed is also suppressed by reducing the output of the engine 1 by the engine control. It is to be noted that the suppression of the overspeed by the engine control is not limited to the reverse movement, but the normal speed shift control unit U.
This is an operation that may be executed in all situations at the time of failure 1.

Next, step S11 is a routine for restarting in the R range. That is, as in step S7, the vehicle starts with the low clutch 70 when restarting. However, since the speed ratio is the fixed ratio Rb (G3), the DSV for the low clutch is used to prevent engine stall.
The vehicle starts while sliding the low clutch 70 by controlling the duty ratio of 206. Next, as in the case of the D range, a warning is issued in step S8, and a method of notifying the user of the failure is aimed at.

(Abnormalities of Sensors) As described above, the toroidal ratio Rt, that is, the actual gear ratio is obtained by using the engine speed Ne and the output disk speed No. Therefore, basically, if the engine speed sensor 301 or the output disk speed sensor 302 fails, the actual gear ratio cannot be calculated. However, when the rotation speed is high (at high vehicle speed), a vehicle speed sensor 303 for detecting the rotation speed of the secondary shaft 13 can be used instead of the output disk rotation speed sensor 302 as shown in FIG. That is, the toroidal ratio Rt is changed to the engine speed N
e and the vehicle speed (the number of rotations of the secondary shaft 13) Ns (Rt = Ne / Ns). However, when the vehicle speed is low and the vehicle speed is low, the signal of the vehicle speed sensor 303 becomes coarse and the calculation error increases. Therefore, this control is performed only at the high vehicle speed.

That is, in steps S12 to S14, it is determined that the rotation sensors 301 to 303 are abnormal. Among them, in particular, it is determined that only the output disk rotation speed sensor 302 is abnormal. Then, the normal speed shift control unit U1 continues the normal speed shift control by using the vehicle speed sensor 303 instead.
However, in step S8, a warning must be issued to notify that a failure has occurred.

On the other hand, the engine speed sensor 301
Is out of order, or when both the output disk rotation speed sensor 302 and the vehicle speed sensor 303 fail, the transmission ratio cannot be calculated.
Proceeding to 16, a general response control operation for a separately set sensor failure is performed.

If no failure is found, the routine proceeds to step S17, where the normal speed shift control unit U
The normal speed change control operation using No. 1 is performed.

[Characteristics of the Toroidal CVT] (1) In the toroidal CVT 10, all the speed change control from the forward movement to the reverse movement is executed using the single normal speed change control valve 230 in the normal state. Therefore, only one SM 239 is required to operate the shift control valve 230. For example, the cost can be significantly reduced as compared to a case where two shift control valves and two actuators are provided for forward and reverse.

(2) On the other hand, in the event of an abnormality, the shift control is executed using the shift control valves 237 and 238 for the time of the abnormality. In this case, the forward shift control valve 237 is used when the vehicle is moving forward and the reverse shift control valve 238 is used when the vehicle is moving backward. It is possible to sufficiently satisfy the driving demand of the driver. In addition, even in abnormal situations where precise control operations are difficult, G
With N as a boundary, it is possible to reliably distinguish between forward traveling and reverse traveling, and it is possible to stably respond to the traveling demand of the driver.

(3) In addition, since the abnormal-time forward shift control valve 237 and the abnormal-time reverse shift control valve 238 are fixed valves that do not require an actuator, the two forward and reverse shift control valves are used. Although 237 and 238 are provided, the cost does not need to increase so much. In other words, even in the event of an abnormality in which the normal-time shift control unit becomes unusable, it is possible to achieve the necessary minimum running performance at the minimum cost and to achieve sufficient fail-safe. In other words, in general, in order to achieve sufficient fail-safe, it is necessary to provide a shift control valve or actuator exclusively for normal, abnormal, forward, or reverse travel, but from the viewpoint of cost. In other words, we want to minimize the number of shift control valves and actuators. The toroidal CVT 10 balances these conflicting requirements as well as possible, and can provide a fail-safe with excellent cost performance.

(4) Further, in the event of an abnormal condition, the shift control unit U2 for the abnormal condition is used and the shift control unit U1 for the normal condition is not used at all. For example, the shift control valve included in the shift control unit U1 for the normal condition is used. Even if the spool 229 sticks, the rod 240 of the SM 239 sticks, or both sticks, it is not affected, and a sufficiently satisfactory shift control can be secured.

(5) In addition, the mechanical movement of the manual valve 203 interlocked with the shift operation by the driver causes the second movement.
The supply and discharge of the operating pressure to and from the Sft 212 are reliably performed, and D
When the range is selected, the shift control valve 237 is switched to the forward shift control valve 237, and when the R range is selected, the shift control valve 238 is switched to the reverse shift control valve 238 smoothly and stably.

[Other Embodiments] In the above embodiments, the tilt angle feedback mechanism is common to the normal shift control unit U1 and the abnormal shift control unit U2. The control unit U1 and the abnormal-time shift control unit U2 may be separately provided. That is, for example, the precess cam is also assembled to another trunnion rod different from the trunnion rod shown in FIG. 5, and the input is also made to another spindle different from the spindle shown in FIG. A lever is provided, and the input lever is brought into contact with the cam surface of the precess cam. One of the support shafts is provided with a normal output lever connected to the link of the normal shift control unit U1, and the other support shaft is provided with a forward shift control valve of the abnormal shift control unit U2 and A forward output lever and a reverse output lever that are engaged with the spool of the reverse speed change control valve are provided.

In this way, the shift operation of the normal-speed shift control unit U1 and the shift operation of the abnormal-time shift control unit U2 can be more clearly separated, and the normal-time shift control unit U1 can also perform the abnormal-time shift control. Even in the part U2, even if any of the spools or rods stick, they do not affect each other,
The possibility that the feedback mechanism is twisted can be completely avoided.

[0080]

As described above, according to the present invention, fail-safe operation can be performed with good cost performance when a shift control valve or an actuator fails. The present invention relates to a toroidal CVT as a continuously variable transmission mounted on an automobile.
Wide use to the general public can be expected.

[Brief description of the drawings]

FIG. 1 shows a toroidal CVT according to an embodiment of the present invention.
It is a skeleton diagram which shows the mechanical structure of.

FIG. 2 is an expanded plan view showing a specific structure of the CVT.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a hydraulic control circuit diagram of the CVT.

FIG. 5 is a schematic view of a tilt angle feedback mechanism.

FIG. 6 is a control system diagram of the CVT.

FIG. 7 is a characteristic diagram showing a relationship between the number of pulses of a step motor and a toroidal ratio.

FIG. 8 is a characteristic diagram showing a relationship between the number of pulses of a step motor and a unit ratio.

FIG. 9 is a shift characteristic diagram of the CVT.

FIG. 10 is a flowchart showing an example of a specific control operation of the CVT.

[Explanation of symbols]

Reference Signs List 10 Toroidal CVT 111, 112 Hydraulic chamber (shift execution unit) 203 Manual valve 212 Second fail-safe shift valve (second switching valve) 215 First fail-safe shift valve (first switching valve) 229 Normal operation Shift control valve 237 Forward shift control valve 238 Reverse shift control valve 239 Step motor 300 Control unit U1 Normal shift control unit U2 Abnormal shift control unit

Claims (4)

[Claims] 1. A control device for a toroidal CVT, comprising: a shift control unit including a shift control valve for generating a shift control hydraulic pressure; and a shift executing unit for executing a shift by the shift control hydraulic pressure, wherein the control device includes: A normal shift control unit including a single shift control valve that controls the forward shift control; an abnormal shift control unit that includes a forward shift control valve that controls only forward travel and a reverse shift control valve that controls only reverse travel; The shift control hydraulic pressure generated by the shift control valve of the normal shift control unit is sometimes used, and the shift control hydraulic pressure generated by the shift control valve of the abnormal shift control unit is used in an abnormal condition. A first switching valve for switching a connection state between the control unit and the shift execution unit; and a forward shift during forward movement when the abnormal-time shift control unit and the shift execution unit are connected by the first switch valve. Generated by the control valve And a second switching valve for switching the connection state between each shift control valve and the shift execution unit such that the shift control hydraulic pressure generated by the reverse shift control valve is used during reverse travel. A control device for a toroidal CVT, comprising: 2. A manual valve for switching an oil passage by operating in response to a shift operation of a driver, wherein the second switching valve is operated by an operating pressure supplied by switching the oil passage of the manual valve. The control device for a toroidal CVT according to claim 1, wherein the connection state is switched by performing the operation. 3. The forward speed change control valve and the reverse speed change control valve are each configured to achieve only a predetermined speed ratio for realizing forward motion or only a predetermined speed ratio for realizing reverse motion. The control device for a toroidal CVT according to claim 1. 4. The toroidal CVT according to claim 1, wherein a low mode and a high mode in which different final speed ratios are achieved at the same speed ratio can be realized during forward movement. Control device.