JP3050039B2 - Hydraulic control circuit for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control circuit for a continuously variable transmission.

[0002]

2. Description of the Related Art A continuously variable transmission is a device having a continuously variable transmission mechanism, a forward / reverse switching device, a torque converter (fluid transmission), and the like. As an example of a hydraulic control circuit of the continuously variable transmission, FIG. 11 is shown. This hydraulic control circuit
A line pressure regulator 2, a clutch pressure regulator 3 and a torque converter pressure regulator 4 are connected in series to an oil pump 1 directly connected to the rotary drive system via oil passages 5a, 5b and 5c. An oil passage 5 g that supplies hydraulic oil to the lubrication system 9 is connected downstream of the lubrication system 9. Further, upstream of each pressure regulating valve, oil passages 5d, 5e, 5f to which supply pressure regulated to the continuously variable transmission mechanism 6, the forward / reverse switching device 7, and the torque converter 8 are supplied are connected. .

The input port 2 of the line pressure regulating valve 2
When hydraulic oil pressurized by the oil pump 1 is supplied to the pilot port 2a and the pilot port 2b, it is expressed by the product of the thrust by the input port 2a and the return spring 2c, the pilot pressure of the pilot port 2b, and the pressure receiving area of the spool land. The line pressure is formed while increasing the pressure until the thrust balances, and this line pressure is supplied to the continuously variable transmission mechanism 6 via the oil passage 5d.

The clutch pressure regulating valve 3 also forms a clutch pressure by the operating pressure supplied from the output port 2d of the line pressure regulating valve 2, and supplies the clutch pressure to the forward / reverse switching device 7 via an oil passage 5e. Further, the torque converter pressure regulating valve 4 also forms the torque converter pressure by the operating pressure supplied from the output port of the clutch pressure regulating valve 2, and supplies the torque converter pressure to the torque converter via the oil passage 5f.

[0005]

However, FIG.
In the conventional hydraulic control circuit shown, for example, comes from the output port 2 d of the circuit upstream of the line pressure regulating valve 2 in valve sticking state can not be output only low pressure hydraulic fluid circuit downstream of the clutch pressure regulating valve 3. Since the clutch pressure and the torque converter pressure cannot be generated in the torque converter pressure regulating valve 4, the vehicle may not be able to travel.

Further, even if the line pressure regulating valve 2 is normal, if the valve stick state is reached in which only low-pressure hydraulic oil can be output from the output port 3a of the clutch pressure regulating valve 3, the torque converter pressure regulating valve 4 Pressure cannot be generated, and the vehicle may not be able to travel. When an oil passage 5g for supplying hydraulic oil to the lubrication system 9 is connected downstream of the pressure regulating valves 2, 3, and 4 connected in series as in the circuit shown in FIG. In the valve stick state, there is a possibility that the supply of the hydraulic oil to the lubrication system 9 may not be possible, but it is desired to secure the minimum supply of the hydraulic oil to the lubrication system 9.

In view of the above, the present invention has been made in view of the above circumstances, and has a stepless circuit having a fail-safe circuit capable of minimizing vehicle traveling even if an abnormality occurs in a control valve constituting a hydraulic control circuit. It is an object to provide a hydraulic control circuit for a transmission.

[0008]

According to a first aspect of the present invention, there is provided a hydraulic control circuit for a continuously variable transmission, wherein a hydraulic oil boosted by an oil pump is regulated to a predetermined supply pressure to control a continuously variable transmission mechanism. In a hydraulic control device for a continuously variable transmission that controls supply to a forward switching device, a fluid transmission device, etc., a first pressure regulating valve that regulates a supply pressure to a continuously variable transmission mechanism and a supply pressure to a forward / reverse switching device are regulated. A second pressure regulating valve to be pressurized is connected in parallel with its input port connected to the oil passage on the discharge side of the oil pump, and the output ports of the first and second pressure regulating valves are converged and converged. A circuit connected to an input port of a third pressure regulating valve for regulating a supply pressure to the fluid transmission device.

The hydraulic control circuit for a continuously variable transmission according to the second aspect is the hydraulic control circuit according to the first aspect,
And a lubricating oil passage for supplying hydraulic oil to a lubricating system is connected to an oil passage connected to an output port of the pressure regulating valve.

[0010]

According to the hydraulic control circuit of the continuously variable transmission according to the first aspect of the present invention, the second pressure regulating valve for regulating the supply pressure to the forward / reverse switching device is in a valve stick state, and the low pressure is supplied from its output port. Even if only hydraulic fluid is output, the third pressure regulating valve disposed downstream is supplied with hydraulic fluid from the first pressure regulating valve disposed in parallel with the second pressure regulating valve, Since the supply pressure to the transmission can be regulated, the vehicle can travel at a minimum.

Further, even if the first pressure regulating valve for regulating the supply pressure to the continuously variable transmission is in a valve stick state and only low-pressure hydraulic oil is output from its output port, it is disposed downstream. Since the third pressure regulating valve is supplied with hydraulic oil from the second pressure regulating valve arranged in parallel with the first pressure regulating valve and can regulate the supply pressure to the fluid transmission device, the minimum number of vehicles Traveling becomes possible.

Since the first pressure regulating valve and the second pressure regulating valve are arranged in parallel with the input port connected to the oil passage on the discharge side of the oil pump, a hydraulic pressure in which a plurality of pressure regulating valves are connected in series is provided. A hydraulic control circuit having a smaller pressure drop than the control circuit is obtained. According to the hydraulic control circuit of the continuously variable transmission according to the second aspect, in addition to the operation according to the first aspect, one of the first pressure regulating valve and the second pressure regulating valve is configured to output a low pressure from the output port. Even in the valve stick state where only the hydraulic oil is output, the hydraulic oil is supplied from the third pressure regulating valve, so that the supply of the hydraulic oil to the lubrication system is reliably ensured.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a skeleton diagram showing a power transmission mechanism of a continuously variable transmission according to an embodiment of the present invention. In the figure, reference numeral 10 denotes an engine as a rotary drive source, and a fluid coupling 12 which is a fluid transmission device is connected to an output shaft 10a. The fluid coupling 12 is provided with a lock-up mechanism, and mechanically connects the input side pump impeller 12b and the output side turpin runner 12c by controlling the hydraulic pressure of the lock-up oil chamber 12a. Can be separated. The output side of the fluid coupling 12 is connected to the rotating shaft 13. Rotary axis 1
3 is connected to the forward / reverse switching mechanism 15. The forward / reverse switching mechanism 15 includes a planetary gear mechanism 17, a forward clutch 40, and a reverse brake 50.

The planetary gear mechanism 17 includes a sun gear 19, 2
It comprises a pinion carrier 25 having two pinion gears 21 and 23, and an internal gear 27. The two pinion gears 21 and 23 mesh with each other, the pinion gear 21 meshes with the sun gear 19, and the pinion gear 23 meshes with the internal gear 27. The sun gear 19 is connected so as to always rotate integrally with the rotating shaft 13. The pinion carrier 25 can be connected to the rotating shaft 13 by a forward clutch 40. The internal gear 27 is provided with a reverse brake 50.
Can be fixed to the stationary part. The pinion carrier 25 is connected to a drive shaft 14 arranged on the outer periphery of the rotation shaft 13, and the drive shaft 14 is provided with a drive pulley 16.

The drive pulley 16 has a fixed conical plate 18 that rotates integrally with the drive shaft 14, a V-shaped pulley groove disposed opposite to the fixed conical plate 18, and a hydraulic pressure acting on the drive pulley cylinder chamber 20. And a movable conical plate 22 that is movable in the axial direction of the drive shaft 14. The drive pulley cylinder chamber 20 is composed of two chambers 20a and 20b, and has a pressure receiving area twice that of a driven pulley cylinder chamber 32 described later. The drive pulley 16 is operatively connected to a driven pulley 26 by a V-belt 24.

The driven pulley 26 is provided on a driven shaft 28. The driven pulley 26 has a fixed conical plate 30 that rotates integrally with the driven shaft 28, and is disposed to face the fixed conical plate 30 to form a V-shaped pulley groove, and the driven shaft is driven by hydraulic pressure acting on the driven pulley cylinder chamber 32. 28, and a movable conical plate 34 that is movable in the axial direction.
The drive pulley 16, the V-belt 24 and the driven pulley 26 constitute a V-belt type continuously variable transmission mechanism 29. A drive gear 46 is fixed to the driven shaft 28, and the drive gear 46 is an idler gear 48 on an idler shaft 52.
Is engaged. The pinion gear 54 provided on the idler shaft 52 always meshes with the final gear 44. A pair of pinion gears 58 and 60 constituting an actuator 56 are attached to the final gear 44. The pinion gears 58 and 60 and a pair of side gears 62 and 6 are attached to the final gear 44.
4 are engaged, and the side gears 62 and 64 are connected to output shafts 66 and 68, respectively.

The engine 10 is connected to the power transmission mechanism as described above.
The rotational force input from the output shaft 10a of the motor 1 is transmitted to the forward / reverse switching mechanism 1 via the fluid coupling 12 and the rotary shaft 13.
5, when the forward clutch 40 is engaged and the reverse brake 50 is released, the rotational force of the rotary shaft 13 is the same via the planetary gear mechanism 17 that is in an integrally rotating state. When the reverse clutch 50 is engaged while the forward clutch 40 is disengaged and the reverse brake 50 is engaged, the rotational force of the rotary shaft 13 is reduced by the action of the planetary gear mechanism 17. The power is transmitted to the drive shaft 14 in an inverted state. The rotational force of the drive shaft 14 is determined by the drive pulley 16, the V-belt 24, the driven pulley 2
6, driven shaft 28, drive gear 46, idler gear 48, idler shaft 52, pinion gear 54, and final gear 4.
4 to the differential 56 and the output shafts 66 and 6
8 rotates in the forward or reverse direction. When both the forward clutch 40 and the reverse brake 50 are released, the power transmission mechanism is in a neutral state.

At the time of the power transmission as described above, the movable conical plate 22 of the driving pulley 16 and the movable conical plate 34 of the driven pulley 26 are moved in the axial direction to change the contact position radius with the V-belt 24. Drive pulley 16 and driven pulley 2
6 can be changed. For example, if the width of the V-shaped pulley groove of the drive pulley 16 is increased and the width of the V-shaped pulley groove of the driven pulley 26 is reduced, the radius of the contact position of the V-belt on the drive pulley 16 side is reduced, and The radius of the contact position of the V belt on the pulley 26 side increases,
Eventually, a large gear ratio can be obtained. Movable conical plate 2
If the gears 2 and 34 are moved in the opposite directions, the gear ratio becomes smaller, contrary to the above.

Next, the hydraulic control device for the continuously variable transmission will be described. As shown in FIG. 2, the hydraulic control device includes an oil pump 101, a line pressure regulating valve 102, a manual valve 104, a shift control valve 106, a step motor 108 as a shift motor, a shift ratio pressure valve 110, a shift operating mechanism 1
12, switching valve 114, pressure modify valve 11
6, a constant pressure regulating valve 118, a modifying duty valve 120, a clutch relief valve 122, a torque converter relief valve 124, a lock-up control valve 126, a lock-up duty valve 128, a clutch on-off control duty valve 129, and the like. ing.

The oil pump 101 sucks the oil in the tank 130 through the strainer 131 and discharges the oil to the oil passage 132. The oil discharged from the oil passage 132 is supplied to the line pressure regulating valve 102.
Are supplied to the ports 102a and 102b of the line, and are adjusted to a predetermined line pressure by the line pressure regulating valve 102,
The adjusted line pressure is applied to the driven pulley cylinder chamber 32,
It is supplied to a port 106a of the shift control valve 106 and a port 114a of the switching valve 114, respectively. The oil passage 132 is provided with a pilot relief valve 133k for suppressing an abnormally high line pressure. An oil passage 132a is connected to the oil passage 132, and the discharge oil discharged from the oil pump 101 passes through the oil passage 132a and is supplied to the input port 122a and the pilot port 122b of the clutch relief valve 122. It has become.

The switching valve 114 has an input port 114a to which the line pressure is supplied, and a port 10 of the line pressure regulating valve 102.
An output port 114b communicating with 2f, a drain port 114c communicating with the tank 130, a pilot port 114d through which the output pressure of the modifying duty valve 120 is supplied as pilot pressure, and a spool 114e.
When the pilot pressure of the pilot port 114d is substantially zero, the input port 114a and the output port 11
4b and the drain port 114c are in communication,
When the pilot pressure of the pilot port 114d increases, the drain port 114c is closed by the spool 114e. The input port 114a of the switching valve 114
The oil passage 133 communicating with the oil passage 132 is interrupted by interposing a separator 133s in the middle of the oil passage 133, and the oil passage 134 communicating the output port 114b and the pilot port 102f of the line pressure regulating valve 102 is formed. It is shut off by interposing a separator 134s on the way.

The pressure-modifying valve 116 has a port 116a connected to the port 102f of the line pressure regulating valve 102, and a pilot port 1 to which the output pressure of the modifying duty valve 120 is supplied as pilot pressure.
16b, drain port 11 connected to tank 130
6c and an input port 116d communicating with an output port 102d of the line pressure regulating valve 102;
e and 116f, and a return spring 116h for urging the spool 116g toward the pilot port 116b. When the pilot pressure of the pilot port 116b is substantially zero, the port 116a and the drain port 116c are provided. When the pilot pressure increases, the spool 116g moves upward in response to this, and the port 116a and 116d communicate with each other.

The constant pressure regulating valve 118 is a line pressure regulating valve 1
Input port 11 connected to the output port 102d
8a, an output port 118b, a pilot port 118d to which the output pressure of the output port 118b is supplied as a pilot pressure via a filter 118c, a drain port 118e connected to a tank 130, and two lands 11
A spool 118h having 8f and 118g and a return spring 118i for urging the spool 118h toward the pilot port 118d are provided, and an orifice 118j is provided at an inlet of the pilot port 118d. The constant pressure regulating valve 118 regulates a constant hydraulic pressure corresponding to the urging force of the spring 118i by a well-known pilot pressure regulating operation, and outputs the regulated hydraulic pressure to the output port 118.
The control duty valve 120, the lock-up duty valve 128, and the clutch engagement / disengagement control duty valve 130 are supplied through b.

In the modification duty valve 120, an input port 120a is connected to an output port 118b of the constant pressure regulating valve 118, and the output port 120b is connected to the switching valve 1.
14, a pilot port 116 b of the pressure modify valve 116, an external pilot port 122 d of the clutch relief valve 122, a drain port 120 c which is in communication with the tank 130, and a target shift supplied from a shift control device 300 described later. A modulating control pressure corresponding to the duty ratio is output from the output port 120b by a driving current having a duty ratio corresponding to the ratio.

The lock-up duty valve 128 has an input port 128a connected to an output port 118b of the constant pressure regulating valve 118, an output port 128b connected to an input port 150a of a shift command valve 150 described later, and a line pressure. Pilot port 102 of pressure regulating valve 102
e, is connected to the pilot port 122c of the clutch relief valve 122, the drain port 128c is connected to the tank 130, and lock-up control is performed from the output port 128b by a drive current having a predetermined duty ratio supplied from the shift control device 300 described later. Output pressure. Here, an oil passage 135 connecting between the output port 128b and the pilot port 102e of the line pressure regulating valve 102 and the pilot port 122c of the clutch relief valve 122.
And 136 are the separators 13 interposed therebetween.
Blocked by 5s and 136s.

The clutch control duty valve 129 has an input port 129a connected to an output port 118b of the constant pressure regulating valve 118, and an output port 129b connected to a reverse brake control valve 140 and a pilot clutch control valve 142, which will be described later. The drain port 129c is communicated with the tank 130, and the output port 129b is connected to the output port 129b by a drive current having a predetermined duty ratio supplied at the time of creep control and anti-skid control from the shift control device 300 described later. And outputs a clutch control pressure P _CC corresponding to.

The line pressure regulating valve 102 has a large-diameter hole 102.
g port 102a, pilot port 102c, medium diameter hole 102 communicating with large diameter hole 102g.
h, a pilot port 102b formed in a small-diameter hole 102i communicating with the medium-diameter hole 102h, and a pilot port 102f formed in an extra-large-diameter hole 102j communicating with the small-diameter hole 102i. And a spool 102s having lands 102o, 102p, 102q, 102r corresponding to the holes 102g to 102j, and a return spring 10 for urging the spool 102s toward the pilot port 102f.
2t, the spool 102s moves left and right due to the thrust of the return spring 102t, the thrust balance between the pilot pressure supplied to the pilot ports 102b, 102c, 102e and 102f and the pressure receiving area, and the spool 102s moves between the input port 102a and the output port 102d. The line pressure is adjusted by adjusting the opening area.

The manual valve 104 is a line pressure regulating valve 1
Input port 104 communicating with the output port 102d
a, R range port 104b, D range port 104
c, L range port 104d and drain ports 104e, 104f at both ends, and two lands 104g, 104
h of the spool 104i. The spool 104i is operated by a select lever (not shown) provided near the driver's seat, and has five stop positions in P, R, N, D, and L ranges. The R range port 104b is connected to the reverse brake 50 via the reverse brake control valve 140,
The c and L range ports 104d are connected to the forward clutch 40 via the forward clutch control valve 142.

The reverse brake control valve 140 has an input port 140a communicating with the R range port 104b of the manual valve 104, and an orifice 140 connected to the reverse brake 50.
b and an output port 140d communicating through 140c,
A pilot port 140 to which an output pressure of a drain port 140e and an output port 140d communicating with the tank 130 is supplied as a pilot pressure via an orifice 140f.
g and a pilot port 140h communicated with an output port 129b of the clutch control duty valve 129;
The spool 140m includes two lands 140i, 140j, and 140k, and a return spring 140n that urges the spool 140m toward the pilot ports 140g and 140h. The orifice 1
The check valves 140o and 40c which prevent the hydraulic oil flowing out from the reverse brake 50 to the reverse brake control valve 140 and the operation flowing into the reverse brake 50 from the reverse brake control valve 140 are provided in parallel to these. A check valve 140p for blocking oil is inserted.

The forward clutch control valve 142 is connected to the D range port 104 c of the manual valve 104 by the orifice 14.
The output pressure of the input port 142b communicating with the forward clutch 2a, the output port 142d communicating with the forward clutch 40 via the orifice 142c, the drain port 142e communicating with the tank 130, and the output pressure of the output port 142d is the orifice 1
Pilot port 142g supplied as pilot pressure via 42f and clutch control duty valve 12
9 pilot port 142h connected to the output port 129b, and three lands 142i, 142j, 142
k, a spool 142m having
And a return spring 142n that urges the pilot ports 142g and 142h. The clutch control valve 142 is connected in parallel with the orifice 142a.
A check valve 142o for preventing the hydraulic oil flowing out from the manual valve 104 into the manual valve 104 is interposed, and the forward clutch 4 is connected to the forward clutch control valve 142 in parallel with the orifice 142c.
A check valve 142p for preventing the hydraulic oil from flowing into zero is inserted.

The clutch relief valve 122 has a large diameter hole 1
An input port 122a and an output port 122d formed at 22e, a pilot port 122b formed at a medium diameter hole 122f communicating with the large diameter hole 122e, and a small diameter hole 122g communicating with the medium diameter hole 122f. The pilot port 122c formed in the
Lands 122h and 122 engaging with 122f and 122g
2i and 122j, and the spool 122k is connected to pilot ports 122b and 122j.
and a return spring 122m biasing to the c side.

Here, the input port 122a is connected to the oil passage 13
The oil pump 1 connected to the oil passage 132a branched from the oil pump 1
01 is supplied, and the pilot port 122b is connected to the oil passage 132a through the orifice 122n.
The pilot port 122c is connected to the output port 120b of the modifying duty valve 120 and the output port 128b of the lock-up duty valve 129, and the output port 122d is connected to the input of the torque converter relief valve 124 via an oil passage 135b. Port 124
a.

When the oil passages 135a and 135b converge, the torque converter relief valve 124 is connected to the output port 122d of the clutch relief valve 122 and the line pressure regulating valve 102.
Input port 124a communicated with the output port 102d of the
, An output port 124b, a spool 124d having one land 124c, and a return spring 124e for urging the spool 124d in a direction to close the output port 124b, and the output port 124b sets a lubricating pressure. The oil is returned to the suction side of the oil pump 101 via the lubrication relief ball 144, and is output for lubrication to a lubrication system such as a differential gear, a power train, and a belt.

The lock-up control valve 126 is connected to the large-diameter hole 1.
An input port 126b connected to an output port 122d of the clutch relief valve 122 formed at 26a, an output port 126c connected to the lock-up oil chamber 12a, and an output port 126 connected to the fluid coupling 12.
d, an output port 126e connected to the cooler 146,
The pilot port 12 communicated through the orifice 148 with the output port 126f communicated with the lubrication system and the drain port 126g communicated with the tank 130 and the output port 126c formed in the small diameter hole 126h through the orifice 148.
6i and a pilot port 126j communicating with the output port 150b of the shift command valve 150, and a large-diameter hole 126a.
Lands 126m, 126n, 126 engaging with
o, 126p and land 12 engaging with small diameter hole 126h
6r, the spool 126s having the
The return spring 126t biases 6s toward the pilot ports 126i and 126j. In addition, a relief valve 152 that suppresses abnormally high pressure is connected to an oil passage 149 that connects the output port 126d and the fluid coupling 12.

The shift control valve 106 is connected to the input port 106
a, output port 106b and pressure adjustment port 106c, 3
And a spool 106g having two lands 106d, 106e and 106f. The input port 106a is connected to an oil passage 132 to which line pressure is supplied, and the output port 106b is connected to the driving pulley cylinder chamber 1 of the driving pulley 16.
0, the pressure adjustment port 106c is communicated with the tank 130 via a pressure adjustment valve 160 that adjusts the driving pulley cylinder pressure to a predetermined pressure, and the spool 106g
Is rotatably connected by a pin 181 to a substantially central portion of a lever 178 of the speed change operation mechanism 112 described later. Therefore, when maintaining a constant gear ratio, as shown in FIG.
06b is closed, so that the drive pulley cylinder chamber 2
The line pressure supply to 0 is in a cutoff state. In this state, when the spool 106g moves upward in FIG. 2, the input port 106a and the output port 106b are in communication with each other, and a predetermined line pressure is supplied to the drive pulley cylinder chamber 20 to increase the pressure. As a result, V of the drive pulley 16
The width of the U-shaped pulley groove is reduced, while the driven pulley 26
The width of the V-shaped pulley groove becomes larger. That is, the V-belt contact radius of the driving pulley 16 increases and the V-belt contact radius of the driven pulley 26 decreases, so that the gear ratio decreases. Conversely, when the spool 106g is moved downward in FIG. 2, the gear ratio is increased due to the completely opposite operation.

As described above, the lever 178 of the speed change operation mechanism 112 is connected to the spool 106g of the speed change control valve 106 by the pin 181 at a substantially central portion thereof, and one end of the lever 178 is connected to the shaft 14 of the drive pulley 16 by the pin 181. A groove 22a provided on the outer periphery of the movable conical plate 22 of the drive pulley 16 with a part of the outer periphery of a flange 164a slidably mounted on a guide shaft 162 having a rectangular cross section arranged in parallel and formed on the outer periphery. And the sensor shoe 164 that moves in accordance with the axial movement of the movable conical plate 22,
The other end is connected to the rod 182 by a pin 185. The rod 182 has a rack 182c.
82c is a pinion gear 108a of the step motor 108
Is engaged.

In such a speed change operation mechanism 112,
When the step motor 108 controlled by the shift control device 300 is driven to rotate clockwise, the rod 182 moves downward, and the lever 178 rotates clockwise around the pin 183 as a fulcrum, and is connected to the lever 178. The spool 106g of the shift control valve 106 is moved downward. Thereby, as described above, the drive pulley cylinder chamber 20
Since the pressure oil in a is returned to the tank 130 via the pressure holding valve 160, the cylinder pressure of the drive pulley cylinder chamber 20a is reduced to the pressure set by the pressure holding valve 160. For this reason, the movable conical plate 22 of the driving pulley 16 moves upward in FIG. 2 and the V-shaped pulley groove interval of the driving pulley 16 increases, and at the same time, the V-shaped pulley of the driven pulley 26 The groove spacing decreases and the gear ratio increases.

Since one end of the lever 178 is connected to the sensor shoe 164 by the pin 183, when the sensor shoe 164 moves upward in FIG. The lever 178 rotates clockwise with the side pin 185 as a fulcrum. For this reason, the spool 106g is pulled upward, and the drive pulley 16 and the driven pulley 26 try to be in a state where the gear ratio is small. By such an operation, the spool 106g, the driving pulley 16 and the driven pulley 26
It is stabilized in the state of the target gear ratio corresponding to the rotation position of the step motor 108.

When the step motor 108 is rotated counterclockwise, the spool 106g of the shift control valve 106 moves upward in FIG. When the pressure is supplied, the V-shaped pulley groove of the driving pulley 16 becomes smaller, the V-shaped pulley groove of the driven pulley 26 becomes larger, and the gear ratio becomes smaller. At this time, the sensor shoe 164 moves downward in FIG. 2 with the movement of the movable conical plate 22 in the drive pulley 16, so that the spool 1 of the shift control valve 106
06g is pulled back downward, and the drive pulley 16 and the driven pulley 26 are about to be brought into a state in which the gear ratio is large. By such an operation, the spool 106g and the driving pulley 1
6 and the driven pulley 26 are stabilized in a state of a target gear ratio corresponding to the rotational position of the step motor 108.

Therefore, when the step motor 108 is operated in accordance with a predetermined shift pattern, the speed ratio changes accordingly, and by controlling the step motor 108, the shift of the continuously variable transmission mechanism is controlled. Can be. The step motor 108 is connected to the transmission control device 3
The rotation angle is determined according to the pulse number signal transmitted from 00. The pulse number signal from shift control device 300 is given according to a predetermined shift pattern according to the running state.

The transmission ratio pressure valve 110 is connected to the input port 110.
a, output port 110b, drain port 110c and pilot port 110d, and three lands 110e,
A spool 110h having 110f and 110g, a spring stopper sliding rod 110i connected to the sensor shoe 164 via a lever 170 having a fulcrum at a substantially central portion, and a spring stopper sliding rod 110i and the spool 110g. A return spring 110j interposed therebetween to bias the spool 110h toward the pilot port 110d. The input port 110a is connected to the input port 118a of the constant pressure regulating valve 118, and the output port 110b is When the V-shaped pulley groove interval of the drive pulley 16 is small, the spring stop sliding rod 110i is communicated with the pilot port 102c of the line pressure regulating valve 102 and its own pilot port 110d.
Takes the upper position, so that the return spring 110j
And the pilot pressure output from the output port 110b decreases, and the line pressure regulating valve 10
The line pressure of the oil passage 132 adjusted in Step 2 becomes small, and from this state, the spring-stopping sliding rod 110i gradually moves downward as the V-shaped pulley groove interval of the drive pulley 16 increases. 110j
And the pilot pressure output from the output port 110b gradually increases, and the oil passage 132
Line pressure gradually increases.

The step motor 108, the modulating valve duty valve 120, the lock-up duty valve 128, and the clutch on / off control duty valve 1
29 is controlled by the shift control device 300. As shown in FIG. 3, the shift control device 300 includes an engine speed sensor 301, a vehicle speed sensor 302, a throttle opening sensor 303, a shift position switch 304, a turbine speed sensor 305, and an engine coolant temperature sensor 30.
6 and an electric signal from the brake sensor 307 are input. The engine speed sensor 301 detects the engine speed from the ignition pulse of the engine, and the vehicle speed sensor 302 detects the vehicle speed from the rotation of the output shaft of the continuously variable transmission. The throttle opening sensor 303 detects the throttle opening of the engine as a voltage signal. The shift position switch 304 detects which of the P, R, N, D, and L positions the manual valve 104 is at. The turbine rotation speed sensor 305 detects the rotation speed of the turbine shaft of the fluid coupling 12. The engine coolant temperature sensor 306 generates a signal when the temperature of the engine coolant is equal to or lower than a predetermined value. Brake sensor 30
7 detects whether or not the brake of the vehicle is being used. Engine speed sensor 301, vehicle speed sensor 302
And the signal from the turbine rotational speed sensor 305 is supplied to the input interface 311 via the waveform shaping circuits 308, 309 and 322, respectively, and the voltage signal from the throttle opening sensor 303 is converted into a digital signal by the A / D converter 310. The data is converted and supplied to the input interface 311.

The shift control device 300 includes an input interface 311, a CPU (central processing unit) 313, a reference pulse generator 312, a ROM (read only memory) 314,
It has at least a RAM (random access memory) 315 and an output interface 316, which are connected by an address bus 319 and a data bus 320.

Here, the reference pulse generator 312 has a CP
Generate a reference pulse to activate U313. ROM
314 includes a step motor 108 and a duty valve 1
A program for controlling 20, 20, and 129 and data necessary for the control are stored. The RAM 315 temporarily stores information from each sensor and switch, parameters necessary for control, and the like.

The output signal from the shift control device 300 is output to the step motor 108 via the amplifier 317, and is also output directly to the electromagnetic solenoids of the duty valves 120, 128 and 129. Then, the transmission control device 30
The speed ratio control of the continuously variable transmission by 0 is executed according to the reference calculation process shown in the flowchart of FIG.

The reference calculation process of the speed ratio control will be briefly described. The calculation process of FIG. 4 is executed by a timer interrupt every predetermined time (ΔT).
Reads the shift position from the shift position switch 304, and then determines in step 504 whether or not the shift position is the D, L, R range, which is the driving range, and determines that it is in the D, L, R range. If so, the process proceeds to step 508;
If the range is the N range, the process proceeds to step 506, in which the duty ratio of the exciting current to the electromagnetic solenoid of the lock-up duty valve 128 is set to “0”, and then to step 630 described below.

In step 508, the throttle opening T is determined based on the signal from the throttle opening sensor 303.
H, and then at step 510 the vehicle speed sensor 302
Based on a signal from the reading of the vehicle speed V, the then shifts from crowded reading the engine rotational speed N _E by the engine speed sensor 305 at step 512 to step 513a.

In this step 513a, the RAM 315
By referring to the map in FIG. 6 calculates the current transmission ratio C _P on the basis of the pulse number P _A of the current stepper motor 110 that is stored in, and then proceeds to step 513b, the throttle opening TH and the engine on the basis of the rotational speed N _E,
Calculating the engine torque T _E by referring to the map showing the relationship between the engine rotational speed N _E and engine torque T _E and the throttle opening degree TH as parameters shown in FIG. 7, then the process proceeds to step 513c, the calculated engine by referring to the map showing the relationship between transmission ratio C _P and the line pressure of the engine torque T _E as shown in FIG. 8 on the basis of and the current transmission ratio C _P torque T _E as a parameter to calculate the line pressure P _L ,
Step 514: determining the duty ratio of the exciting current to the corresponding modifier duty valve 120 to output the pilot pressure supplied to the pressure regulator valve 102 from the pressure modifier valve 116 to obtain the line pressure P _L. Move to In FIG. 8, the gear ratio C _low = 2.50, C _High = 0.
It is set to 497.

[0049] In step 514, based on a signal from the turbine speed sensor 305 reads the turbine speed N _t, then the process proceeds to step 516, the rotation of the said engine speed N _E and the turbine rotation speed N _t calculating a deviation N _D, then in step 518, step 5
Based on the throttle opening TH read at step 08 and the vehicle speed V read at step 510, the lock-up ON vehicle speed V _ON and the rop-up OFF vehicle speed V _OFF are stored in accordance with the control map shown in FIG. Search for.

Next, the routine proceeds to step 520, where it is determined whether or not the drop-up flag LUF is set to "1". If the drop-up flag LUF is set to "1", the flow proceeds to step 544. The process proceeds to step 522 if not. In step 544, it is determined whether or not the vehicle speed V is lower than the lock-up off vehicle speed V _OFF . If V <V _OFF , the process proceeds to step 540. If not, that is, if V ≧ V _OFF The process proceeds to step 546. On the other hand, if it is determined in step 522 that the vehicle speed V is higher than the lock-up on vehicle speed V _{ON, the process} proceeds to step 524,
If not, the process proceeds to step 540. At step 524, from said rotational difference N _D by subtracting the first target value Nm ₁ calculates a rotational target value deviation e, then depending from a previously stored control map at step 526 to the rotary target value deviation e First feedback gain G ₁
The search, then the rotational difference N _D in step 528 it is determined whether the smaller than the control system switching threshold N _0, N _D <
Proceeds to step 530 when it is N _O, the process proceeds to step 538 if it is the case namely N _D ≧ N _O otherwise. In step 530, a minute predetermined value α is added to the previous duty ratio of the lock-up duty valve 128 to set the current duty ratio of the lock-up duty valve 128, and then in step 532, the lock-up duty valve The current duty ratio of 128 is 1
It is determined whether it is less than 00% or not. If it is determined that it is less than 100%, the process proceeds to step 601; otherwise, the process proceeds to step 534.

In step 534, the current duty ratio of the lock-up duty valve 128 is corrected to 100%. Next, in step 536, the drop-up flag LUF is set to "1", and the routine proceeds to step 601.
On the other hand, in step 538, the current duty ratio is set to the rotation target value deviation e and the first feedback gain G.
_The calculation is performed based on an arithmetic expression using ₁ as a variable, and the process proceeds to step 601.

In step 540, the current duty ratio of the lock-up duty valve 128 is set to 0%. Then, in step 542, the lock-up flag LUF is set.
Is reset to "0", and the routine goes to the step 601. In step 546, the current duty ratio of the lock-up duty valve 128 is set to 100%, and the routine proceeds to step 601.

At step 601, it is determined whether or not the vehicle is under anti-skid control. In this anti-skid control, when the brake pedal is depressed while the vehicle is running to bring the brake state, the wheel cylinder pressure increases and the wheel speed decreases, but the slip ratio at that time exceeds a predetermined value. When the wheel cylinder pressure at that time is held, when the wheel deceleration exceeds the set value in this holding state, it is determined that the wheels are in the tendency to lock, and the wheel cylinder pressure is reduced to avoid the locked state Thereafter, when the wheel speed recovers, the braking state is continued while repeating the holding state, the slowly increasing pressure state, the holding state and the depressurizing state, thereby preventing the locking of the wheels and obtaining a good braking state. When the anti-skid control is started, the anti-skid control flag is set to "1" to indicate the anti-skid control flag. By determining the whether "1", it is possible to determine whether the anti-skid control in.

If the anti-skid control is not being performed, the process directly proceeds to step S602. If the anti-skid control is being performed, the process proceeds to step 601a, where the duty of the exciting current to the electromagnetic solenoid of the clutch control duty valve 129 is determined. The ratio is set to 100%, and the process proceeds to step 602. In step 602, the vehicle speed V is set to a predetermined gear ratio control start threshold V
₀ (e.g., set to 2-3 km / h, which is smaller than V _ON and V _OFF as shown in FIG. 5), and if it is determined that V <V ₀ , When it is determined that creep control is necessary, the process proceeds to step 604,
If not, that is, if V ≧ V _0, it is determined that shift control needs to be performed, and the routine proceeds to step 624. Determines whether the throttle opening TH in the step 604 is smaller than the idle determination threshold TH _0, TH <TH
_If it is determined to be ₀ , the process proceeds to step 610,
Otherwise, that is, when it is determined that TH ≧ TH ₀ , the process proceeds to step 606. Step 606
Then, the current duty ratio of the clutch control duty valve 129 is set to 0%, and the forward clutch 40 or the reverse brake 50 is completely engaged.
In step 8, the target number of pulses P _D to the step motor 110 is set to zero, and the process proceeds to step 630 described later.

On the other hand, if it is determined in step 610 that the changeover detection switch 298 is on,
Then, the process proceeds to step 620. Wherein in the step 612 the rotation of the deviation N _D by subtracting the second target value Nm ₂ calculates a rotational target value deviation e, then depending from previously stored control map at step 614 to the rotary target value deviation e Find the second feedback gain G _2, then the current duty ratio of the clutch control duty valve 129 at step 616, based on the operation expression to the rotation target value deviation e and the second feedback gain G ₂ variables , Then step 61
Is set to "0" the current number of pulses P _A to the step motor 110 proceeds to step 636 at 8.

Further, in step 624, it is determined whether or not the shift position is in the D range. If the shift position is in the D range, the process proceeds to step 626, and the vehicle speed V is calculated from the previously stored shift pattern corresponding to the D range. Then, a gear ratio corresponding to the throttle opening TH is searched, and the routine proceeds to step 630. If the result of determination in step 624 is that the shift position is not in the D range, step 639
Then, it is determined whether the shift position is in the L range. If the shift position is in the L range, the process proceeds to step 628, where the vehicle speed V and the throttle opening are determined from the previously stored shift pattern corresponding to the L range. A gear ratio corresponding to the degree TH is searched, and the routine proceeds to step 630. If the result of the determination in step 639 is that the shift position is not in the L range, the flow shifts to step 644, and
Then, a speed ratio corresponding to the vehicle speed V and the throttle opening TH is retrieved from a speed change pattern corresponding to the shift position R range stored in advance, and the routine proceeds to step 630.

Meanwhile, the process proceeds to step 636 if the current number of pulses P _A in the step 630 is determined to be equal to the target number of pulses P _D. Step 6
At 30, it is determined whether the current pulse number P _A is smaller than the target pulse number P _{D. If} it is determined that P _A <P _D , the process proceeds to step 632 to shift the step motor drive signal in the upshift direction. moving, then after updating stored as a new current pulse number P _a "1" is added to the current pulse number P _a at step 634, the process proceeds to step 636. On the other hand, when the current pulse number P _A in the step 630 is determined to be greater than the target number of pulses P _D, the process proceeds to move the stepper motor drive signal to the down-shift direction to the step 620, then step 622 in after updating stored as a new current pulse number P _a by subtracting "1" from the current pulse number P _a, the process proceeds to step 636.

In step 636, the step motor drive signal is output. Next, in step 638, the solenoid valve solenoid drive signal is output, and the process returns to the main program. In this embodiment, steps 626 and 628 except for the search of the shift pattern corresponding to the R range in step 644 are performed.
It can be considered that the speed ratio of the continuously variable transmission is set according to the speed change pattern as shown in FIG. That is, the speed ratio in each speed change pattern is uniquely set by searching on a control map having the vehicle speed V and the throttle opening TH as variables according to those variables. FIG. 9 shows the relationship between the vehicle speed V on the horizontal axis and the engine speed Ne.
Is assumed to be a comprehensive control map of a shift pattern using the vertical axis as a parameter and the throttle opening TH as a parameter, a straight line having a constant slope passing through the origin may be considered as having a constant speed ratio. , The straight line having the largest slope is the largest reduction ratio of the entire vehicle, that is, the maximum gear ratio C _Hi , and the straight line having the smallest slope is the smallest the reduction ratio of the entire vehicle, that is, the minimum gear ratio in the D range. C
You can think of it as _DLO . Therefore, specifically, the shift pattern in the L range is fixed to the maximum gear ratio C _Hi irrespective of the vehicle speed V and the throttle opening TH, and the shift pattern in the D range is the maximum gear ratio C _Hi and the minimum in the D range. The vehicle speed V and the throttle opening T in the region between the speed change ratio C _DLO
It becomes a control curve composed of a time-dependent locus of the speed ratio set according to H.

Therefore, it is assumed that the vehicle is in a parking state in which the engine is stopped and the P range is selected by the shift lever. In this state, the V-belt type continuously variable transmission 29
However, as shown in FIG.
On the side of the contact position radius of minimum dynamic pulley 26 side of the contact position radius is assumed to maximum speed ratio C _MAX switch 298 out switching換検In the shift position of which the largest is in the ON state.

When the ignition switch is turned on and the engine is started from this parking state, and the engine is brought into an idling state, the oil pump 101 is driven to rotate in response thereto, whereby the discharge pressure to the oil passage 132 increases, and this is Pilot port 102b of pressure regulating valve 102
To the oil passage 132
a of the input port 12 of the clutch relief valve 122
2a and 122b.

[0061] On the other hand, setting the central processing unit 313 when the ignition switch is turned on, resets the lock-up flag LUF performed initialized to "0", the target pulse number P _D to "0" Then, the processing of FIG. 4 is executed. At this time, since the P range has been selected with the shift lever, steps 504 to 50 are executed.
6 proceeds to the transition from set to the duty ratio of the lockup duty valve 128 "0" in step 630, this time, the current pulse number P _A is the target number of pulses P
_If it is determined that _D (= 0) is satisfied, a drive signal for maintaining the step motor 108 in a stopped state is output (step 636), and then a solenoid drive signal having a duty ratio “0” is output to each of the duty valves 120, 128 and 129. For this reason, the modifier duty valve 120
Maintains the duty ratio of zero, and its output port 1
The modifier pressure output from 20b becomes zero,
Since this is input to the pilot port 116b of the pressure modifier valve 116, the input port 116d and the output port 116a of the pressure modifier valve 116 are shut off, and the output port 116a
And the drain port 116c communicate with each other, so that the pilot pressure of the pilot port 102f of the line pressure regulating valve 102 also becomes zero.

Then, the oil passage 13 is
2a is supplied to the input ports 122a and 122b of the clutch relief valve 122, and the clutch pressure P formed by the input port 122a is
_C increases to a pressure at which the thrust by the return spring 122m of the clutch relief valve 122, the thrust expressed by the product of the pilot pressure of the pilot port 122b and the pressure receiving area of the land 122i of the spool 122k is balanced.

The output port of the line pressure regulating valve 102
The output pressure output from 102d is the transmission ratio control valve
110 is supplied to the input port 110a of the
The V-shaped pulley groove interval of the pulley 16 is wide.
Therefore, in response to this, the sensor shoe 164 is moved upward in FIG.
To the side, so that the spring-stopping sliding rod 1
10i moves downward to return spring 110j.
Of the transmission ratio control valve 1
The control pressure output from the output port 110b of the
Touch pressure P_CLower than, but close to,
This control pressure is the pilot port of the line pressure regulating valve 102.
102c is supplied as pilot pressure. For this reason,
The spool 102s of the line pressure regulating valve 102 moves left and enters.
The opening area between the force port 102a and the land 102o is
As a result, the line pressure of the oil passage 132 is reduced as shown in FIG.
As shown in FIG._MAXMaximum transmission ratio on
C _MAXAt a relatively high line pressure represented by the point corresponding to
Is determined.

When the D range is selected with the shift lever in order to start the forward running while keeping the brake pedal depressed from the stopped state in which the P range is selected,
When the process of FIG. 4 is executed, the process shifts from step 504 to step 508 to start the shift control process. However, in the state where the brake pedal is continuously depressed, the engine is in the idling state and the vehicle is also in the stopped state.
The duty ratio of the modifier duty valve 120 calculated in 3a~S513c is not a minimum a value corresponding to the engine torque idling, increase modifier pressure P _M that is output from the duty valve 120 slightly, which Pressure modifier valve 1 according to
16 output ports 116a and drain port 116c
Between the output ports 116a.
And between the input port 116d is to become the communicating state, modifier pressure relatively small pressure based on the clutch pressure P _C is supplied to the pilot port 102f of the line pressure regulating valve 102 as a pilot pressure. Therefore, the spool 102s is moved to the right, the line pressure P _L of the channel 132 in FIG. 8
As shown in, it is set to the maximum speed ratio C _MAX on the minimum line pressure curve L _MIN a minimum line pressure at the maximum speed ratio C _MAX represented by a point corresponding.

[0065] On the other hand, when selecting the D range by the shift lever, the input port 104a and the output port 104c of the manual valve 104 is in the communicating state, the clutch pressure P _C is forward clutch formed by clutch relief valve 122 Since the forward clutch 40 is supplied to the forward clutch 40 via the control valve 142 via the orifice 142c, the forward clutch 40 gradually increases and enters the one-time engagement state. However, in the process of FIG. 4, the lock-up flag LUF
Is reset to "0" in the initial state, the process proceeds from step 520 to step 522, and since the vehicle speed V is zero, the process proceeds to step 540 to change the duty ratio of the lock-up duty valve 128 to "0". 0 ”,
Next, the processing shifts to step 542 to reset the lock-up flag LUF to “0”, and then shifts to step 602.

Here, since the vehicle speed V is stopped and smaller than the set vehicle speed V ₀ , the flow shifts to step 604, where the throttle opening TH is in the idling state, so that the set value T
Since it is smaller than H ₀ , the flow shifts to step 610, and since the changeover detection switch 298 is on,
2~S616 proceeds to, based on the duty ratio of the clutch control duty valve 129 to the difference e and the gain G ₂ of the deviation N _D and the target deviation N _{m @ 2} of the engine rotational speed N _E and the turbine rotational speed N _T The duty ratio is set to a relatively large value, for example, about 60. Therefore, the clutch control pressure P _{since CC} is supplied to the pilot port of the clutch control valve 140 and 142, spool 142m a return of the clutch control valve 140 and 142 output from the output port 129b of the clutch control duty valve 129 It descends against the spring 142m, and the output port 142d and the drain port 142e
Is communicated, and the clutch engagement pressure for the forward clutch 40 is reduced to a pressure at which the urging force of the return spring 142n and the thrust by the pilot pressure of the pilot port 142h are balanced, thereby controlling creep running to be possible. .

On the other hand, the lock-up duty valve 128
Becomes "0", the lock-up control pressure to be outputted is controlled to be substantially zero, and this is the pilot port 126j of the lock-up control valve 126.
Is supplied as pilot pressure to the spool 126.
s is moved rightward by the return spring 126t as shown in FIG. 2, and the torque converter control pressure _PT supplied from the torque converter relief valve 124 is supplied to the lock-up oil chamber 12a via the input port 126b and the output port 126c. The operating pressure is supplied to the fluid coupling 12 from the lock-up oil chamber 12 a side, and the hydraulic pressure of the fluid coupling 12 is maintained by the pressure holding valve 150.
Is maintained at a constant pressure. For this reason, the lock-up release state in which the fluid coupling 12 connects the pump impeller 12b and the turbine runner 12c via the hydraulic oil is controlled. The hydraulic oil output from the fluid coupling 12 is supplied to the lock-up control valve 12.
6 to the cooler 146 via the input port 126c and the output port 126e.

Therefore, in this state, the brake pedal
Release the depression and release the accelerator pedal, or
Is lightly depressed and the throttle opening TH is equal to the set value TH.₀Less than
Is maintained, the forward clutch 40 is slightly engaged.
And the rotational driving force of the engine 10 becomes full.
Coupling 12, forward clutch 40 and planetary gear
Drive pulley 16 via planet carrier 25 of
To the engine 10 through the fluid coupling 12.
The maximum speed ratio C by absorbing the overload _MAXDeku
Leap running is possible.

Further, in order to start from a stopped state in which the D range is selected and the brake pedal is depressed, the depression of the brake pedal is released, and instead the accelerator pedal is depressed greatly, whereby the throttle opening TH is reduced. If the value is greater than the set value TH ₀ , the process proceeds from step 604 to step 606 when the process of FIG. 4 is executed, and the duty ratio of the clutch control duty valve 129 is “0”.
, And then at step 608, the target pulse number P _D
Is set to the number of pulses “0” representing the maximum gear ratio C _MAX as shown in FIG. At this time, since the current pulse number P _A is “0”, P _A = P
_In step 636 and step S638, a step motor drive signal and a solenoid drive signal are output. Therefore, the clutch control pressure _PCC output from the clutch control duty valve 129 becomes zero, the spool 142m of the forward clutch control valve 142 is raised by the return spring 142m, and the output port 142d and the drain port 142e are connected. Shut off and conversely output port 1
42d and the input port 142b are brought into communication with each other, the clutch engagement pressure for the forward clutch 40 is increased, the forward clutch 40 is controlled to be completely engaged, and the step motor 108 is controlled to the pulse number shown in FIG. It is maintained at the position of the maximum gear ratio _CMAX of "0".

As described above, the forward clutch 40 is in the fastening state.
State, the maximum gear ratio C _MAXStarted the vehicle at
At this time, the throttle opening TH is large.
As a result, step 513 in the process of FIG.
a to the line pressure P set in S513c_LAlso engine
The maximum line pressure curve L in FIG._MAXupper
Maximum gear ratio C_MAXThe maximum pressure at the point corresponding to
Is supplied to the cylinder chamber 32 of the driven pulley 26,
Pressing force corresponding to the engine torque against the belt 24
Acts to reduce slippage between belt 24 and pulleys 16 and 26.
A good start can be performed by suppressing this.

Thereafter, the vehicle speed V is changed to the set vehicle speed V ₀ shown in FIG.
4, when the process of FIG. 4 is executed, the process proceeds from step 602 to step 624, and since the range is the D range, the process proceeds to step 626, where the vehicle speed V, the engine speed _NE, and the throttle opening to determine the target pulse number P _D of the step motor 108 to the degree TH by referring to the D-range shift pattern stored in advance on the basis of representing the target gear ratio, it starts the shift control.

That is, when the target pulse number P _D is set to a value larger than “0”, the process shifts from step 630 in the process of FIG. 4 to steps 632 and S634, and the current pulse number P _A of the step motor 108 is set. “1”
By incrementing the value by updating stored as a new current pulse number P _A, then the process proceeds to step 636, and outputs the current motor driving signal corresponding to the pulse number P _A to the step motor 108, the step motor 10
8 is rotated counterclockwise by a predetermined step angle as viewed in FIG. This rotation processing is performed by setting the target pulse number P _D and the current pulse number P
Repeatedly until _A matches. As a result, the rod 182 moves upward as shown in FIG.
8 is a pin 183 which is a connection point with the sensor shoe 164.
Pivoted counterclockwise to the position shown by the broken line with
The spool 106g of the transmission control valve 106 connected to the lever 178 via the pin 181 moves upward. As a result, the input port 10 of the shift control valve 106
6a and the output port 106b is communicated with each other, since the line pressure P _L supplied to the input port 106a is supplied to the cylinder chamber 20a of the drive pulley 16, the movable conical plate 22 is moved to the fixed conical plate 18 side The gap between the V-shaped pulley grooves is reduced, thereby increasing the radius of the contact position of the belt 24 with the driving pulley 16 and correspondingly decreasing the radius of the contact position with the driven pulley 26, thereby gradually reducing the gear ratio. . On the other hand, the sensor shoe 164 moves downward due to the movement of the movable conical plate 22, whereby the lever 178 rotates counterclockwise about the pin 185 of the rod 182,
When the spool 106g of the shift control valve 106 is lowered, the output port 106b is gradually closed by the land 106e, and when the output port 106b matches the target gear ratio, the output port 106g is closed.
Since b is completely closed by the land 106e, the pressure rise in the cylinder chamber 20a of the drive pulley 16 is stopped, and the movement of the movable conical plate 22 is stopped.

As described above, when the speed ratio of the continuously variable transmission 29 decreases, the duty ratio of the modifier duty valve 120 calculated in steps 513a to 513c of FIG. 4 increases, and accordingly, the pressure modifier valve 116 output modifier pressure P _M that is output from the port 116a is increased line pressure regulating valve 10 of the
As the pilot pressure supplied to the second pilot port 102f increases, the downward movement of the sensor shoe 164 causes the spring stop sliding rod 110i of the transmission ratio pressure valve 110 to move upward, thereby reducing the urging force of the return spring 110j, In response to this, the pilot pressure of the line pressure regulating valve 102 output from the output port 110b to the pilot port 102c decreases,
Spool 102s is moved rightward of line pressure regulating valve 102, by the opening area between the input port 102a and the land 102o increases thereby, the line pressure P _L is reduced, the pressure in the cylinder chamber 32 of the driven pulley 26 Is reduced, the belt holding force is changed to a belt clamping force according to the gear ratio.

Thereafter, when the vehicle speed V increases while maintaining the state where the throttle opening TH is large and exceeds the lock-up ON vehicle speed V _ON , the process proceeds from step 522 to step 524 in the processing of FIG. calculating a rotation target value deviation e from the rotational speed deviation N _D between the engine rotational speed N _E and the turbine runner rotation speed N _t by subtracting the first target value Nm _1, then pre-stored control map at step 526 , A first feedback gain G ₁ corresponding to the rotation target value deviation e is searched, and then step 528 is executed.
In determines the or rotational speed deviation N _D is less than the control system switching threshold N _0. If it is N _D ≧ N _O, the process proceeds to step 538 it is determined that the rotation speed deviation is too large, corresponding to the duty ratio for the lockup duty valve 128 to the rotational speed deviation e and the feedback gain G ₁ Set to a value to perform feedback control. Therefore, when the solenoid drive signal is output to the lock-up duty valve 128 in step 638, the lock-up control pressure P _LU output from the output port 128b is gradually increased, and this is changed to the speed change command valve 150. Pilot port 126 of lock-up control valve 126 through input ports 150a and 150b of
j, the spool 126s moves leftward against the return spring 126t, and the torque converter pressure P supplied to the lock-up oil chamber 12a is increased.
_T is gradually reduced and fluid coupling 1
The amount of hydraulic oil output from 2 to the cooler 146 is also reduced, and the pressure in the lock-up oil chamber 12a is reduced, whereby the lock-up state is gradually switched.

When the rotational speed deviation N _D becomes smaller than the control system switching threshold value N _{0, the} process proceeds from step 528 to step 530 in FIG. 4, and feedforward control for adding a predetermined value α to the current lock-up duty ratio. And if this is less than 100%, step 53
4, the duty ratio is set to 100%, and then in step 536, the lock-up control flag LUF is set to "1", and then the process proceeds to step 602.

For this reason, the lock-up duty valve 1
The lock-up control pressure P _LU outputted from the lock-up control valve 126 becomes a high pressure.
6s further moves to the left, connects the lock-up oil chamber 12a to the drain port 126g, supplies the torque converter pressure _PT directly to the fluid coupling 12, and further sets the lubrication pressure P set by the lubrication relief ball 144.
_{The LB} is supplied to the cooler 146 via the input port 126f and the output port 126e and is cooled.

As a result, the pressure in the lock-up oil chamber 12a becomes substantially zero, so that the lock-up state is established in which the pump impeller 12b and the turbine runner 12c are mechanically connected, and the vehicle continues to accelerate. When the desired vehicle speed V is reached and the depression of the accelerator pedal is stopped,
Throttle opening TH becomes constant value, the engine rotational speed is also constant, the target number of pulses P _D to be searched in step 626 is a constant value, this and since the current number of pulses P _A are matched, in FIG. 4 since the current to maintain the pulse number P _a shifts from step 630 to step 636 in the processing, the shift operation is not performed, the constant speed traveling state is maintained.

When the accelerator pedal is released from the constant speed running state to bring the engine brake state or the brake pedal is pressed to bring the braking state, the throttle opening TH is reduced, and the search is made in step 626. The target number of pulses P _D decreases, which causes step 6
30 to step 620, and the step motor 1
08 of the drive signals to the downshift direction, and then the current pulse number P _A at step 622 is decremented by "1". For this reason, the step motor 108 is rotated clockwise in FIG. 10, whereby the rod 182 moves downward, whereby the lever 178 pivots clockwise about the pin 183 of the sensor shoe 164 as a fulcrum. When the spool 106g of the shift control valve 106 is lowered, the output port 106b and the drain port 106c communicate with each other, and the operating oil in the cylinder chamber 20a of the drive pulley 16 is gradually returned to the tank 130 via the pressure holding valve 160. . Therefore, the pressure in the cylinder chamber 20a of the drive pulley 16 gradually decreases, so that the interval between the V-shaped pulley grooves gradually increases, and the radius of the contact position of the belt 24 with the drive pulley 16 gradually decreases. As the radius of the contact position of the belt 24 with the pulley 26 gradually increases, the speed ratio C gradually increases to perform a downshift, and the vehicle is decelerated.

When the vehicle speed V becomes _lower than the lock-up off vehicle speed V _OFF while continuing the deceleration state, the process proceeds from step 544 to step 540 in the processing of FIG.
The duty ratio for the lock-up duty valve 128 is set to “0”, and then in step 542, the lock-up control flag LUF is reset to “0”.
For this reason, the pressure of the pilot port 126j of the lock-up control valve 126 decreases, and the spool 12
6s instantaneously moves rightward, and the torque converter pressure _PT is supplied to the lock-up oil chamber 12a. Therefore, the lock-up state is immediately released, and the drive state is returned to the driving state via the fluid coupling 12, and during this time, the continuously variable transmission is performed. The speed ratio C of the engine 29 continues to increase, and when the vehicle speed V becomes lower than the set vehicle speed V ₀ , the process proceeds from step 602 to step 604. Since the throttle opening TH is smaller than the set value TH ₀ , the process proceeds to step 610. and, when the current pulse number P _A is "0" i.e. not reached the maximum speed ratio C _MAX, the step 620
In step 622, the step motor 108 is rotated in the downshift direction, and the current pulse number P _A is decremented by “1”, and the current pulse number P _A becomes “0”.
When it reaches, it moves to step 612 and as described above,
The clutch pressure of the forward clutch 40 is reduced to return to a state in which creep traveling is possible.

While the deceleration state is continued, the movable conical plate 22 of the drive pulley 16 moves upward, and the sensor shoe 164 descends, so that the output pressure of the speed ratio pressure valve 110 increases. As a result, the pilot pressure at the pilot port 102c of the line pressure regulating valve 102 increases, so that the line pressure decreases and the belt clamping force of the driven pulley 26 is adjusted to a value corresponding to the shift position.

When the anti-skid control is started at the time of braking, the anti-skid control flag is set to "1" as described above, so that the process shifts from step 601 to step 601a in the processing of FIG. hand,
Since the duty ratio of the exciting current to the electromagnetic solenoid of the clutch control duty valve 129 is set to 100%, when the solenoid drive signal is output to the clutch control duty valve 129 in step 636, the clutch control duty valve 129 is output. clutch control pressure P _CC outputted from the output port 129b becomes higher pressure, which pilot port 14 of the forward clutch control valve 142
2h, the spool 142m descends against the return spring 142n, whereby the output port 142d and the drain port 142e communicate with each other, so that the clutch pressure of the forward clutch 40 decreases. In addition, it is possible to prevent the load due to the fluctuation of the wheel speed from acting on the engine 10.

When the shift lever is shifted from the D-range to the N-range after the vehicle has changed from a running state to a stopped state, the spool 1 of the manual valve 104 is correspondingly shifted.
2 moves downward in FIG. 2, the D range port 104c communicates with the drain port 104f, but the input port 142b of the clutch control valve 142
Check valve 142 in the oil passage between
o, the clutch control valve 142
The hydraulic oil flowing out of the input port 142b returns to the tank 130 through the D range port 104c and the drain port 104f through the orifice 142a, and the clutch pressure of the forward clutch 40 is gradually reduced. Shock at the time of shifting to the N range can be prevented.

Here, in the hydraulic control apparatus for the continuously variable transmission according to the present embodiment, even when the line pressure normal pressure valve 102 or the clutch relief valve 122 is in the valve stick state for some reason, the running state of the vehicle is not changed. Is provided with a fail-safe circuit. That is, the circuit will be described with reference to FIG.
An oil passage 132a is branched from an oil passage 132 connected to the discharge side of the oil passage 132. The input port 102a of the line pressure regulating valve 102 is connected to the oil passage 132a, and the input port 122a of the clutch relief valve 122 is connected to the oil passage 132.
a, the line pressure regulating valve 102 and the clutch relief valve 122 are arranged in parallel.
The output port 102d of the line pressure regulating valve 102
And the output port 122d of the clutch relief valve 122 are converged via oil passages 135a and 135b, and the convergent path is connected to the input port 124a of the torque converter relief valve 124. The oil passage 1 connected to the output port 124b of the torque converter relief valve 124
35d, a lubricating oil passage 135d for supplying hydraulic oil to the lubrication system
Is connected.

Thus, for example, even when the clutch relief valve 122 is in a valve stick state and only low-pressure hydraulic oil is output from its output port 122d, the torque converter relief valve 124 disposed downstream is Hydraulic oil is supplied from the line pressure regulating valve 102 arranged in parallel with the clutch relief valve 122 via an oil passage 135a, and the hydraulic pressure is supplied to the torque converter 12 (lock-up oil chamber 12a, fluid coupling 12). Since the supply control can be performed, it is possible to perform the minimum traveling of the vehicle.

Also, for example, even when the line pressure regulating valve 102 is in a valve stick state and only low-pressure hydraulic oil is output from its output port 102d, the torque converter relief valve 124 disposed downstream is provided.
Since hydraulic oil is supplied from a clutch relief valve 122 disposed in parallel with the line pressure regulating valve 102 via an oil passage 135b, the supply of the torque converter control pressure to the torque converter 12 can be controlled. Vehicle traveling can be enabled.

Therefore, even if one of the line pressure regulating valve 102 and the clutch relief valve 122 constituting the hydraulic control circuit is in a valve stick state in which only low-pressure hydraulic oil is output from the output port, at least It is possible to provide a hydraulic control circuit of a continuously variable transmission capable of running the vehicle. In the present embodiment, the line pressure regulating valve 102 and the clutch relief valve 122 are connected to the input port 1.
02a, 122a are connected to the oil passages 132, 132a on the discharge side of the oil pump 101 and are arranged in parallel.
A hydraulic control circuit with a small pressure drop can be obtained.

Even if either the line pressure regulating valve 102 or the clutch relief valve 122 is in the valve stick state, the hydraulic oil is reliably supplied from the lubricating oil passage 135d to the lubricating system via the torque converter relief valve 124. can do.

[0088]

As described above, according to the first aspect of the present invention,
According to the hydraulic control circuit of the continuously variable transmission described above, the second pressure regulating valve that regulates the supply pressure to the forward / reverse switching device is in a valve stick state, and only low-pressure hydraulic oil is output from its output port. However, the third pressure regulating valve disposed downstream is the first pressure regulating valve arranged in parallel with the second pressure regulating valve.
Hydraulic oil is supplied from the pressure regulating valve, and the supply pressure to the fluid transmission device can be regulated, so that the vehicle can travel at a minimum and the supply pressure to the continuously variable transmission can be regulated. Even if the first pressure regulating valve to be pressurized is in a valve stick state and only low-pressure hydraulic oil is output from its output port, the third pressure regulating valve provided downstream is the first pressure regulating valve.
Hydraulic oil is supplied from the second pressure regulating valve arranged in parallel with the pressure regulating valve, and the supply pressure to the fluid transmission device can be regulated, so that the vehicle can travel at a minimum. Therefore, even when the first pressure regulating valve or the second pressure regulating valve constituting the hydraulic control circuit is in a valve stick state in which only low-pressure hydraulic oil is output from its output port, a minimum vehicle travel is possible. A hydraulic control circuit for a continuously variable transmission having a possible fail-safe mechanism can be provided.

Further, since the first pressure regulating valve and the second pressure regulating valve are connected in parallel by connecting the input port to the oil passage on the discharge side of the oil pump, it is possible to obtain a hydraulic control circuit with a small pressure drop. it can. According to the hydraulic control circuit for a continuously variable transmission according to the second aspect, in addition to the effect according to the first aspect, one of the first pressure regulating valve and the second pressure regulating valve is connected to the output port so that the pressure is low. Even in the valve stick state where only the hydraulic oil is output, the hydraulic oil is supplied from the third pressure regulating valve, so that the supply of the hydraulic oil to the lubrication system can be reliably ensured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a power transmission mechanism of a continuously variable transmission.

FIG. 2 is a diagram showing a hydraulic control device for a continuously variable transmission according to the present invention.

FIG. 3 is a diagram illustrating a shift control device of the continuously variable transmission.

FIG. 4 is a diagram showing a control routine of a transmission.

FIG. 5 is a diagram showing a relationship between a throttle opening and a vehicle speed.

FIG. 6 is a diagram showing a relationship between a gear ratio and a step motor position.

FIG. 7 is a diagram showing the relationship between engine torque and engine speed.

FIG. 8 is a diagram showing a relationship between a line pressure and a gear ratio.

FIG. 9 is a diagram showing a shift pattern of the continuously variable transmission.

FIG. 10 is a diagram showing an operation of the speed change operation mechanism.

FIG. 11 is a diagram showing a hydraulic control circuit of a conventional continuously variable transmission.

[Explanation of symbols]

 Reference Signs List 12 fluid transmission device (torque converter) 15 forward / reverse switching device 29 continuously variable transmission mechanism 101 oil pump 102 first pressure regulator (line pressure regulator) 102a input port 102d output port 122 second pressure regulator (clutch relief valve) 122a input port 122d output port 124 third pressure regulating valve (torque converter relief valve) 124a input port 124b output port 132, 132a, 135a, 135b oil passage 135d lubrication oil passage

Claims (2)

(57) [Claims] 1. A hydraulic control device for a continuously variable transmission for controlling hydraulic oil pressurized by an oil pump to a predetermined supply pressure to control supply to a continuously variable transmission mechanism, a forward / reverse switching device, a fluid transmission device, and the like. A first pressure regulating valve for regulating the supply pressure to the continuously variable transmission mechanism, and a second pressure regulating valve for regulating the supply pressure to the forward / reverse switching device,
These input ports are connected to the oil passage on the discharge side of the oil pump and arranged in parallel, and the first and second
A hydraulic control circuit for a continuously variable transmission, wherein the output port of the pressure regulating valve is converged, and the converging path is connected to the input port of a third pressure regulating valve for regulating the supply pressure to the fluid transmission device. . 2. The continuously variable transmission according to claim 1, wherein a lubricating oil passage for supplying hydraulic oil to a lubricating system is connected to an oil passage connected to an output port of the third pressure regulating valve. Machine hydraulic control circuit.