JPH06207670A - Control device for belt type continuous variable transmission - Google Patents

Abstract

PURPOSE:To prevent overspeed of an engine by providing a hydraulic circuit in which a speed change ratio control valve and a regulator valve are connected to a selector valve through a manual valve so that a control hydraulic pressure is fed to the speed change ratio control valve and to the regulator valve from the selector valve when the manual valve is set at a specific position due to abnormal operation of a control valve. CONSTITUTION:A speed change ratio control valve 21 and a regulator valve 20 are connected a selector valve 26 by means of hydraulic circuits 61, 62, 64 through the intermediary of a manual valve 27. Further, when control valves 30 to 34 for controlling the selector valve 26 are closed and the manual valve 27 is set to a specific position due to occurrence of an abnormality, a control hydraulic pressure is fed to the speed change ratio control valve 21 and the regulator valve 20 from the selector valve 26 so that they are controlled toward the low speed stage and a predetermined line pressure is ensured.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A belt type continuously variable transmission is a transmission that uses a belt and a pulley to continuously change a gear ratio, and as shown in FIG. 1, an engine, an electromagnetic clutch, a fluid coupling, etc. A primary pulley (input shaft) 1 driven via a not shown), a secondary pulley (output shaft) 2 connected to a front axle, and a primary pulley 1 and a secondary pulley 2 that are wound around the primary pulley 1 and the secondary pulley 2. The belt 3 and the hydraulic control device 4 that controls the groove widths Wp and Ws of the primary pulley 1 and the secondary pulley 2 are configured.

Primary pulley 1, secondary pulley 2
Is provided with shafts 1a and 2a having predetermined inclined surfaces, movable sheaves 1b and 2b, and primary cylinders 1c and secondary cylinders 2c provided on the back surfaces of the movable sheaves 1b and 2b, respectively. , Ball splines are slidable on the shafts 1a, 2a, and a primary hydraulic pressure P supplied from the hydraulic control device 4 is supplied.
p, groove width Wp, Ws of the pulley by the secondary hydraulic pressure Ps
Can be changed. The hydraulic control device 4 includes an electronic control device (not shown),
Groove width W of the primary pulley 1 and secondary pulley 2 is controlled by inputting respective signals such as engine speed and vehicle speed and controlling the hydraulic pressure supplied from the hydraulic pump 5 based on these signals.
Control p, Ws.

That is, in the low state, as shown in FIG. 2, the groove width Wp of the primary pulley 1 is wide, the groove width Ws of the secondary pulley 2 is narrow, and the gear ratio is large. On the contrary, in the overdrive state, as shown in FIG. 3, the groove width Wp of the primary pulley 1 is narrow, the groove width Ws of the secondary pulley 2 is wide, and the gear ratio is small. By the way, in the belt type continuously variable transmission as described above, in order to change the gear ratio by changing the groove widths Wp and Ws between the primary pulley 1 and the secondary pulley 2, the low speed stage side and the high speed stage side are changed. There is a limit to the gear ratio. Therefore, by using an auxiliary transmission that has two forward gears and is connected in series to the output shaft of the secondary pulley 2 of the continuously variable transmission, the shift range can be changed by switching between the low speed gear and the high speed gear. There is known a two-stage belt type continuously variable transmission adapted to take a wide range. The switching between the high speed side and the low speed side of the belt type continuously variable transmission is performed by the first solenoid valve.
When the solenoid valve is de-energized, the continuously variable transmission is switched to the high speed stage side. Further, switching between the low speed gear and the high speed gear of the auxiliary transmission is performed by the second solenoid valve so that the auxiliary transmission can also be switched to the high speed gear when the second solenoid valve is not energized. Has become. When both the first and second solenoid valves are de-energized, the belt gear ratio is shifted to the higher speed stage to prevent engine overspeed. These first and second solenoid valves are controlled by an electronic control unit.

[0005]

However, in the two-stage belt type continuously variable transmission having the above-described structure, the electronic control device such as the first and second solenoid valves or the electronic device for controlling these solenoid valves is used. When the control device breaks down, the sub-transmission becomes the forward two-speed high-speed side, and the speed ratio of the belt of the continuously variable transmission is shifted to the high-speed side, resulting in insufficient climbing performance. There is.

The present invention has been made in view of the above points, and a solenoid valve for switching between a low speed gear and a high speed gear of a sub transmission of a two-stage belt type continuously variable transmission and a belt type continuously variable transmission. Provided is a control device for a belt-type continuously variable transmission, which prevents an engine from over-rotating and ensures climbing performance when an electronic control device such as a solenoid valve for switching between a low speed stage and a high speed stage is abnormal. The purpose is to

[0007]

In order to achieve the above object, according to the present invention, an auxiliary transmission having at least two speed stages connected in series to a belt type continuously variable transmission, and the belt type continuously variable transmission. A gear ratio control valve that controls the gear ratio of the continuously variable transmission to a low speed side when the control hydraulic pressure is high and a high speed side when the control hydraulic pressure is low, and a regulator valve that regulates the line pressure supplied to the continuously variable transmission according to the control hydraulic pressure. A switching valve for controlling the shift stage of the auxiliary transmission by control hydraulic pressure, control valves for supplying control hydraulic pressure to each valve, a manual valve, and an electronic control device for controlling each control valve. In a control device for a belt-type continuously variable transmission having the above-mentioned, a hydraulic circuit for connecting the speed ratio control valve and the regulator valve to the switching valve via the manual valve is provided. A configuration in which the control oil pressure is supplied from the switching valve to the gear ratio control valve and the regulator valve when a control valve for controlling the switching valve is closed due to an abnormality and the manual valve is at a specific position Is.

[0008]

When each control valve is deenergized due to an abnormality in the electronic control unit to be in the off state, the gear ratio control valve switches the continuously variable transmission to the high speed side, and the regulator valve drives the high speed side. Adjust to a sufficient line pressure. Also,
The switching valve is opened to switch the auxiliary transmission to the high speed stage side. The manual valve has a specific position, that is, L position or R
When switched to the position, the control oil pressure is supplied from the switching valve to the gear ratio control valve and the regulator valve, and the gear ratio control valve switches the continuously variable transmission to the low speed side,
The regulator valve regulates the line pressure to be sufficient for traveling on the low speed stage side. This provides the required functionality.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 4 shows a hydraulic circuit configuration of a control device 10 for a two-stage belt type continuously variable transmission. A hydraulic pump 11 has an oil filter 1 having a suction port immersed in an oil pan 13.
2, the discharge port is connected via the oil passage 50 to the port 20b of the regulator valve 20, the port 21b of the gear ratio control valve 21, the secondary cylinder 2c of the secondary pulley 2 (FIG. 1), the control hydraulic pressure modulator valve 22, and the clutch modulator. It is connected to each input port of the valve 23. The primary cylinder 1c of the primary pulley 1 (FIG. 1) is connected to the port 2 of the gear ratio control valve 21.
It is connected to 1a. A line pressure relief valve 24 is connected to the oil passage 50.

The discharge port of the control hydraulic modulator valve 22 is connected to an oil passage 51, and the oil passage 51 has a gear ratio control valve 21, a clutch pressure control valve 25, a switching valve 26, and a damper clutch control valve 28. Each control input port of is connected. The control input port of the control hydraulic modulator valve 22 is connected to the oil passage 51. Further, each input port of the solenoid valves 30 to 34 is connected to the oil passage 51. And
The discharge port of the solenoid valve 30 is connected to the control input port 20d of the regulator valve 20 via the oil passage 52.
The discharge port of the solenoid valve 31 is connected to the control input port 21e of the gear ratio control valve 21 via the oil passage 53, and the discharge port of the solenoid valve 32 is connected to the control input port of the clutch pressure control valve 25 via the oil passage 54. The discharge port of the solenoid valve 33 is connected to the control input port 26e of the switching valve 26 via the oil passage 55, and the discharge port of the solenoid valve 34 is connected to the control input port of the damper clutch control hull 28 via the oil passage 65. Each is connected. These solenoid valves 30 to 34 are normally closed type valves and are controlled by an electronic control unit (not shown).

Input port 2 of clutch pressure control valve 25
5a is connected to the discharge port of the clutch modulator valve 23 via the oil passage 56, and the discharge port 25b is connected to the input port 27 of the manual valve 27 via the oil passage 57.
connected to a. The discharge ports 27b and 27c of the manual valve 27 are connected to the forward low speed stage brake 37 of the auxiliary transmission 35 and also connected to the input port 26a of the switching valve 26 via the oil passage 58.
The discharge port 26 b of No. 6 is connected to the auxiliary transmission 3 via the oil passage 59.
5 is connected to the forward high speed clutch 36. Also,
The discharge port 27d of the manual valve 27 is connected to the reverse brake 38 of the auxiliary transmission 35 via an oil passage 60. The discharge port 26c of the switching valve 26 is connected to the input port 27e of the manual valve 27 via the oil passage 61, and the discharge port 27f of the manual valve 27.
Is connected to the control input port 21e of the gear ratio control valve 21 via an oil passage 62, and is connected to the control input port 20e of the regulator valve 20 via an oil passage 64. In addition, the discharge port 2 of the regulator valve 20
0x is connected to the suction port side of the hydraulic pump 11 via the oil passage 63.

The two input ports of the damper clutch control valve 28 are connected to the discharge ports of the regulator valve 20 and the clutch modulator valve 23 via oil passages 66 and 67, respectively, and the two discharge ports are connected to the oil passages 68 and 69, respectively. To the fluid coupling 40, and the other discharge port is connected to the oil cooler 41 via the oil passage 70.
A pressure control valve 29 that controls the hydraulic pressure supplied to the fluid coupling 40 is connected between the oil passages 66 and 63.

The operation will be described below. The control hydraulic pressure modulator valve 22 regulates a line pressure PL, which will be described later, to a predetermined solenoid valve supply pressure (control source pressure) Pv to control the oil passage 50.
To discharge. The clutch modulator valve 23 regulates the line pressure PL to a predetermined clutch supply pressure Pvc (<Pv) and supplies it to the clutch pressure control valve 25.

The solenoid valve 30 is duty-controlled by the electronic control unit according to the vehicle speed, generates a control oil pressure Pvb (≤Pv) from the input solenoid supply pressure Pv, and supplies it to the port 20d of the regulator valve 20. The regulator valve 20 uses the control oil pressure Pvb.
In accordance with the above, the high pressure hydraulic pressure discharged from the hydraulic pump 11 is adjusted to a predetermined line pressure PL and supplied to the secondary cylinder 2c and the port 21b of the gear ratio control valve 21. The regulator valve 20 increases the line pressure PL when the vehicle speed is on the low speed stage side, and adjusts the line pressure PL when the vehicle speed is on the high speed stage side to be lower than that on the low speed stage side.

The solenoid valve 31 is duty-controlled by the electronic control unit according to the vehicle speed, generates a control oil pressure Pva (≤Pv) from the input solenoid supply pressure Pv, and supplies it to the port 21c of the gear ratio control valve 21. To do. The control oil pressure Pva is high when the gear ratio is on the low speed side, and is low as the gear ratio is on the high speed side. The gear ratio control valve 21 has a difference between the solenoid supply pressure Pv supplied from the oil passage 51 to the port 21d and the spring pressure of the spring, and the control hydraulic pressure Pva supplied from the solenoid valve 31 to the port 21c and the spring pressure of the spring. The spool position is controlled by the pressure, and the gear ratio is switched between the low speed side and the high speed side.

That is, in the gear ratio control valve 21, when the control oil pressure Pva is high, the spool moves to the left as shown in the figure, and the oil in the primary cylinder 1c is discharged to the discharge port 21x.
To be discharged from. This widens the groove width Wp of the primary pulley 1 (FIG. 1). On the other hand, the line pressure PL is constantly supplied to the secondary cylinder 2c, and the groove width Ws of the secondary pulley 2 becomes narrow. As a result, the gear ratio is controlled to the low speed stage (low) side.

When the control oil pressure Pva of the solenoid valve 31 is lowered, the spool of the gear ratio control valve 21 is pushed to the right in the figure, and the primary cylinder 1c is discharged to the discharge port 21.
The line pressure PL is also supplied to the primary cylinder 1c by being disconnected from x and gradually communicating with the port 21b. The primary cylinder 1c has a larger pressure receiving area than the secondary cylinder 2c (FIG. 1), and therefore the pressing force of the primary cylinder 1c is equal to that of the secondary cylinder 2c.
It becomes larger than the pressing force of c, and as a result, the groove width Wp of the primary pulley 1 is narrow, and the groove width W of the secondary pulley 2 is small.
s becomes wider (FIG. 2), and the gear ratio is controlled to the higher gear side.

When the control oil pressure Pva of the solenoid valve 31 becomes further lower, the spool of the gear ratio control valve 21 is pushed further to the right, and the primary cylinder 1c moves to port 2.
1b is in full communication, which results in a primary pulley 1
Has a minimum groove width Wp, the secondary pulley 2 has a maximum groove width Ws (FIG. 3), and the gear ratio is in the overdrive state.

The solenoid valve 32 is duty-controlled by the electronic control unit and generates a control oil pressure Pvd from the solenoid supply pressure Pv. That is, when the manual valve 27 is P (parking) or N (neutral), the valve is opened to output the control oil pressure Pvd (= Pv).
Immediately after 7 is moved to R (reverse) or D (forward), duty control is performed for a short time, and then the valve is closed to control hydraulic pressure P.
vd becomes 0.

The clutch pressure control valve 25 has a control oil pressure Pv supplied from the solenoid valve 32 to the port 25c.
d and the spring force of the spring, and the oil passage 51 to the port 25d
The clutch supply pressure Pvc from the clutch modulator valve 23 is supplied to the manual valve 27, which is controlled by the differential pressure from the solenoid supply pressure Pv supplied to the manual valve 27. When the manual valve 27 is in the L (low speed) position (range), the port 27a is in communication with the ports 27b and 27c, the ports 27e and 27f are in communication, and in the 2 and D positions, the ports 27a and 27b are in communication. Is
In addition, when the ports 27e and 27f are cut off and the N (neutral) position is established, the port 27a is replaced with another port 27 as shown in the figure.
b to 27d are blocked, and the port 27e is blocked,
Ports 27a and 27d when in the R (reverse) position
And 27f are communicated with each other, and ports 27a and 27e are closed at the P (parking) position.

The solenoid valve 33 is duty-controlled by the electronic control unit and generates a control oil pressure Pve according to the duty ratio from the solenoid supply pressure Pv. When the low speed side of the auxiliary transmission 35 is selected, the duty ratio is around 100% (Pve = Pv), and when the high speed side is selected, the duty ratio is 0% and 100%.
It is set to an intermediate level in the vicinity (0 <Pve <Pv). Then, when de-energized, the valve is closed and the control oil pressure Pve becomes zero.

The switching valve 26 is a solenoid valve 33.
When the control oil pressure Pve supplied from the port 26e to the port 26e is low (= 0), the spool is pushed to the left by the spring and the ports 26d and 26c and the port 26a as shown in the figure.
And 26b are communicated with each other, and the control oil pressure Pve is high (= P
In the case of v), the spool is pushed to the right in the figure against the spring force, the ports 26d and 26c and the ports 26a and 26b are cut off, and when the control oil pressure Pve is medium, the spool moves slightly to the right. Pushed to ports 26d and 2
6c is cut off, and ports 26a and 26b are connected. That is, the switching valve 26 is switched by the control oil pressure Pve supplied from the solenoid valve 33.

The manual valve 27 has a forward gear (L,
2, D position), the port 27a is connected to the port 27b, and the clutch low supply speed brake 37 of the auxiliary transmission 35 is constantly supplied with the clutch supply pressure Pvc. For example, when the manual valve 27 is in the D position, the clutch supply pressure Pvc is supplied to the forward low speed brake 37. Then, the control oil pressure Pve of the solenoid valve 33
Is between the duty ratio of 0% and 100%, the switching valve 26 has the port 26d shut off.
The ports 26a and 26b communicate with each other. As a result, the clutch supply pressure Pvc is changed to the oil passage 58, the switching valve 26, and the oil passage 5.
It is also supplied to the forward high speed clutch 36 through 9. In the auxiliary transmission 35, when the clutch supply pressure Pvc is supplied to the forward high speed clutch 36, the low speed forward brake 38 is disengaged by the hydraulic servo mechanism to switch to the high speed side gear. At this time, the high speed stage side and the low speed stage side do not interfere with each other.

Further, the control oil pressure P of the solenoid valve 33
When ve is close to 100%, the switching valve 26 has the port 26d closed and the port 26b closed.
Is blocked from the port 26a and communicated with the discharge port. As a result, the oil in the forward high speed clutch 36 is discharged, and in the auxiliary transmission 35, the clutch supply pressure Pvc is supplied only to the low forward speed clutch 37, and the auxiliary transmission 35 is switched to the low speed gear.

As described above, when the low speed side gear of the two-stage auxiliary transmission 35 is selected, the duty ratio of the solenoid valve 33 is controlled to around 100%, and when the high speed side gear is selected, the duty ratio is 0%. And control in the middle of around 100%. Now, the manual valve 27 is D or 2
When in the position, the electronic control unit fails and the solenoid valves 30-34 are de-energized. When the solenoid valve 30 is deenergized and the control oil pressure Pvb is no longer supplied to the port 20d, the regulator valve 20 weakens the force for pushing the spool to the left, and regulates the line pressure PL to a low value. In the gear ratio control valve 21, the solenoid valve 31 is deenergized so that the control oil pressure Pva is applied to the port 21c.
Is no longer supplied, the spool is pushed to the left so that the ports 21a and 21b communicate with each other, the line pressure PL is supplied to the primary cylinder 1c, and the speed is changed to the higher gear side. Further, in the clutch pressure control valve 25, the solenoid valve 32 is deenergized and the control oil pressure Pvd is applied to the port 25c.
Is no longer supplied, the spool is pushed to the left and opened, and the clutch supply pressure Pvc is constantly supplied to the maneuver valve 27.

The switching valve 26 is a solenoid valve 33.
When the control oil pressure Pve is no longer supplied to the port 26e, the spool is pushed leftward to the position shown in the figure, and the port 26d is opened and communicated with the port 26c. At this time, the port 26a communicates with 26b. Therefore, the clutch supply pressure Pvc is continuously supplied to the forward high speed clutch 36 of the auxiliary transmission 35 and is held in the high speed gear. Further, the solenoid supply pressure Pv of the oil passage 51
Is supplied from the switching valve 26 to the port 27e of the manual valve 27 through the oil passage 61. When the manual valve 27 is in the D or 2 position, the ports 27e and 27 are provided.
Therefore, the solenoid supply pressure Pv supplied to the port 27e remains unchanged.

The manual valve 27 is operated from the above D or 2 position to, for example, the L position (downshift).
The port 27e and the port 27f are communicated with each other, and the solenoid supply pressure Pv is supplied to the control input port 21e of the gear ratio control valve 21 through the oil passage 62. The gear ratio control valve 21 uses the differential pressure between the solenoid supply pressure Pv applied to the right side of the spool from the port 21e and the spring pressure of the spring, and the differential pressure between the solenoid supply pressure Pv applied to the left side of the spool from the port 21d and the spring pressure of the spring. The spool moves to the left, the primary cylinder 1c is blocked from the port 21b, and is communicated with the discharge port 21x. As a result, the oil in the primary cylinder 1c is discharged to widen the groove width Wp of the primary pulley 1 (FIG. 1), while the line pressure PL is supplied to the secondary cylinder 2c, so that the groove width of the secondary pulley 2 is increased. Ws becomes narrower, so that the gear ratio is controlled to the lower speed side.

On the other hand, the solenoid valve 30 is supplied with the solenoid supply pressure Pv instead of the control oil pressure Pvb from the solenoid valve 30, and the solenoid supply pressure Pv and the spring pressure of the sprig applied to the right side of the spool from the port 20e and the port 20a. Therefore, the line pressure PL is adjusted according to the pressure difference between the line pressure PL applied to the left side of the spool and the spring pressure of the spring. Then, the line pressure PL is adjusted to a hydraulic pressure high enough for traveling on the low speed stage side.

Even when the manual valve 27 is operated to the R (reverse) position, the ports 27e and 27f are communicated with each other, and the gear ratio control valve 21 is controlled to the low speed stage side as in the case of the L position described above. The regulator valve 20 is
Adjust the line pressure to a high pressure. Also, the manual valve 2
7, the port 27a and the port 27d communicate with each other, and the clutch supply pressure Pvc is supplied to the reverse brake 38 of the auxiliary transmission 35.

When the solenoid valve 33 is de-energized and closed when the electronic control device is in a failure state, the switching valve 26 is opened, and the solenoid of the oil passage 51 is supplied through the switching valve 26. The pressure Pv is the oil passage 61,
It is supplied as a fail detecting oil pressure to a fail detecting oil pressure circuit constituted by 62 and 64, and the fail detecting oil pressure produces a function required when the electronic control device fails. For example, when the electronic control unit fails, the high speed stage side is selected when the manual valve 27 is in the D or 2 position (range), the low speed stage side is selected when the manual valve 27 is in the R or L position, and the line pressure PL is adjusted to a high pressure. Is pressed. As a result, it is possible to prevent the engine from over-rotating due to a downshift at the time of failure during high-speed traveling and to ensure climbing performance.

[0031]

As described above, according to the present invention, 2
A solenoid valve that switches between the high-speed side and the low-speed side of a multi-stage belt type continuously variable transmission is used to detect the failure state of the electronic control device and create the necessary function when the electronic control device fails. As a result, it is not necessary to separately provide a dedicated solenoid valve at the time of failure, and it is possible to reduce costs. Also, it is possible to prevent the engine from over-rotating due to a downshift at the time of failure during high-speed running, and at the same time to ensure climbing performance, and the durability of the belt is impaired during running on the high speed stage side at the time of failure. There is an effect that it is not necessary to supply an unnecessarily high line pressure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a belt type continuously variable transmission.

FIG. 2 is a perspective view showing a state of a low speed stage side (low side) of the transmission of FIG.

FIG. 3 is a high speed stage side (overdrive side) of the transmission of FIG.
It is a perspective view showing the state.

FIG. 4 is a configuration diagram of a hydraulic circuit showing an embodiment of a control device for a belt type continuously variable transmission to which the present invention is applied.

[Explanation of symbols]

 1 Primary Pulley 1c Primary Cylinder 2 Secondary Pulley 2c Secondary Cylinder 3 Belt 10 Hydraulic Control Unit 11 Hydraulic Pump 20 Regulator Valve 21 Gear Ratio Control Valve 22 Control Pressure Modulator Valve 23 Clutch Modulator Valve 25 Clutch Pressure Control Valve 26 Switching Valve 27 Manual Valve 30 ~ 34 Solenoid valve 35 Auxiliary transmission 36 Forward high speed clutch 37 Forward low speed brake 38 Reverse brake 40 Fluid coupling

Claims (1)

[Claims] 1. A sub-transmission which is connected in series to a belt type continuously variable transmission and has at least two gear stages, and a gear ratio of the belt type continuously variable transmission is low toward a low speed stage when a control oil pressure is high. Sometimes, a gear ratio control valve for controlling to the high speed stage side, a regulator valve for adjusting the line pressure supplied to the continuously variable transmission according to the control hydraulic pressure, and a switching valve for controlling the shift stage of the auxiliary transmission by the control hydraulic pressure. In the control device for a belt type continuously variable transmission, each control valve supplying a control hydraulic pressure to each valve, a manual valve, and an electronic control device controlling each control valve,
The switching valve is provided with a hydraulic circuit that connects the speed ratio control valve and the regulator valve via the manual valve, the control valve controlling the switching valve is closed due to an abnormality, and the manual valve is at a specific position. A control device for a belt type continuously variable transmission, wherein the control oil pressure is supplied from the switching valve to the gear ratio control valve and the regulator valve at a certain time.