JP4396247B2 - Hydraulic control device for belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission, and more particularly to a hydraulic control device for a belt-type continuously variable transmission.

  Conventionally, belt-type continuously variable transmissions, planetary gear-type stepped transmissions, and toroidal-type continuously variable transmissions are known as automatic transmissions configured to hydraulically control the transmission mechanism. Among these, the belt-type continuously variable transmission includes a driving side rotating member and a driven side rotating member, and a winding transmission member wound around the driving side rotating member and the driven side rotating member. The gear ratio is controlled by hydraulically controlling the winding radius of the winding transmission member.

  The belt type continuously variable transmission is provided with an input shaft to which engine torque is input, an output shaft provided in parallel with the input shaft, a primary pulley provided on the input shaft side, and an output shaft side. And a secondary pulley. The primary pulley has a fixed sheave fixed to the input shaft and a movable sheave movable in the axial direction of the input shaft. The secondary pulley has a fixed sheave fixed to the output shaft and a movable sheave movable in the axial direction of the output shaft. A belt is wound around the primary pulley and the secondary pulley configured as described above. Furthermore, a first hydraulic chamber (fluid pressure chamber) that controls the operation of the movable sheave of the primary pulley and a second hydraulic chamber that controls the operation of the movable sheave of the secondary pulley are provided.

  Further, a shift control unit is provided for controlling the hydraulic pressure in the first hydraulic chamber. The speed change control unit is provided with a speed increasing solenoid valve and a speed reducing solenoid valve connected to the line pressure control valve, and a speed increasing flow rate control valve and a speed reducing flow rate control valve. The speed increasing flow control valve includes a spool, a control pressure chamber, a spring chamber, an input port and an output port. The deceleration flow control valve includes a spool, a control pressure chamber, a spring chamber, an input port, and a drain port. The control pressure chamber of the acceleration flow control valve is connected to the output port of the acceleration solenoid valve, and the output port of the acceleration flow control valve is connected to the first hydraulic chamber.

  On the other hand, the input port of the deceleration flow control valve is connected to the first hydraulic chamber, and the control pressure chamber of the deceleration flow control valve is connected to the output port of the deceleration solenoid valve. The output port of the speed increasing solenoid valve is connected to the spring chamber of the speed reducing flow control valve. Further, the output port of the deceleration solenoid valve is connected to the spring chamber of the acceleration flow control valve. The output port of the belt pressure hydraulic control valve is connected to the second hydraulic chamber, and the line pressure is input to the input port of the belt pressure hydraulic control valve.

  In the configuration as described above, the discharge hydraulic pressure of the oil pump is controlled to a predetermined line pressure by the line pressure control valve, and the line pressure is applied to the input port of the speed increasing flow control valve and the input port of the belt pressing hydraulic control valve. Entered. Here, in the shift control unit, the flow rate of the oil (fluid) supplied to the first hydraulic chamber via the speed increasing flow control valve is changed by switching the combination of on / off of the two solenoid valves. The flow rate of oil discharged from the first hydraulic chamber via the deceleration flow control valve is controlled.

  In this way, by controlling the hydraulic pressure in the first hydraulic chamber, the groove width of the primary pulley, in other words, the winding radius of the belt on the primary pulley side changes, and the gear ratio is controlled. Further, by controlling the hydraulic pressure in the second hydraulic chamber, the clamping force with respect to the belt is controlled, and the tension corresponding to the transmission torque is ensured.

  With respect to problems that occur due to individual differences in hydraulic equipment in the hydraulic control circuit of such a continuously variable transmission, there are techniques disclosed in the following publications.

  Japanese Examined Patent Publication No. 7-117150 (Japanese Patent Laid-Open No. 4-131564: Patent Document 1) discloses a vehicle in which the adjustment accuracy of the control hydraulic pressure does not decrease due to individual differences of the pressure adjustment valve that generates the basic hydraulic pressure. A hydraulic control device for a belt type continuously variable transmission is disclosed. This hydraulic control device for a belt-type continuously variable transmission for a vehicle is a belt-type continuously variable transmission for a vehicle in which power is transmitted via a transmission belt, and at least throttles a basic hydraulic pressure to apply a clamping pressure to the transmission belt. Pressure regulation valve that can regulate pressure based on pressure and gear ratio pressure, and output signal pressure that changes continuously according to control signal value is supplied to the pressure regulation valve. The pressure is regulated by a pressure regulating valve, a linear valve that has a low optimum pressure, a regulator that adjusts the output signal pressure of the linear valve so that the difference between the basic hydraulic pressure and the optimum pressure calculated from the relationship stored in advance is eliminated. A hydraulic pressure sensor for detecting the hydraulic pressure, output signal pressure stopping means for stopping supply of the output signal pressure to the pressure regulating valve, and output signal pressure supply to the pressure regulating valve being stopped by the output signal pressure stopping means. To detect the actual basic pressure by the hydraulic pressure sensor, and a learning means for configuring a relation for calculating the basic hydraulic pressure based on the basic hydraulic pressure.

  According to the hydraulic control device for the belt type continuously variable transmission for a vehicle, the actual basic hydraulic pressure is detected by the hydraulic sensor in the state where the supply of the output signal pressure to the pressure regulating valve is stopped by the output signal pressure stop means in the learning means. Then, a relationship for calculating the basic hydraulic pressure is configured based on the basic hydraulic pressure. For this reason, even if the output characteristics of the basic hydraulic pressure change due to individual differences in the pressure regulating valve, the basic hydraulic pressure calculated from the corrected relationship can be appropriately approximated to the actual basic hydraulic pressure. This prevents a decrease in control hydraulic pressure adjustment accuracy.

  Japanese Patent Laid-Open No. 9-217800 (Patent Document 2) configures a system at low cost by learning correction using a hydraulic switch, and makes the learning process and determination relatively simple by making the correction operation work under conditions where the hydraulic pressure does not affect performance. A highly reliable hydraulic control device such as a belt-type continuously variable transmission is disclosed. This hydraulic control device such as a belt type continuously variable transmission is a transmission hydraulic control device capable of controlling an operating pressure used for hydraulic operation of a transmission mechanism of a vehicle, and the magnitude of the operating pressure depends on the operation of the transmission. The hydraulic pressure for detection is generated under conditions that do not affect the hydraulic pressure, and the correction amount of the hydraulic pressure is learned and controlled according to the presence or absence of a response of the hydraulic pressure detecting means in the hydraulic pressure circuit at that time.

According to the hydraulic control device such as the belt type continuously variable transmission, in the control device for the operating pressure used for the hydraulic operation of the transmission mechanism, the hydraulic pressure for detection is such that the magnitude of the operating pressure does not affect the operation of the transmission. And the correction amount of the operating pressure can be learned and controlled according to the presence or absence of the response of the hydraulic pressure detecting means in the operating pressure circuit at that time. Accordingly, it is possible to appropriately and easily perform self-correction of the operating pressure without using an expensive hydraulic sensor in feedback control, and to configure a system at low cost by learning correction by a simple hydraulic switch, and , Hydraulic control device that has the function to enable accurate operating pressure control regardless of variations in output pressure due to individual differences such as solenoids used in the system, and without depending on aging Can be realized. Further, by making the correction operation work under conditions where the hydraulic pressure does not affect the performance, the learning process and determination can be made relatively simple and highly reliable.
Japanese Patent Publication No. 7-117150 (Japanese Patent Laid-Open No. 4-131564) JP-A-9-217800

  However, in the hydraulic control device that controls the oil pump discharge pressure and the belt narrowing pressure independently, when learning control is performed using the technique disclosed in the above publication, the following problems arise. Hydraulic circuit with linear solenoid valve that controls relief valve (pressure reducing valve) that regulates oil pump discharge pressure to line pressure, and linear solenoid valve that controls relief valve (pressure reducing valve) that regulates line pressure to belt narrow pressure In order to learn individual differences between the linear solenoids and the relief valves (reducing valves), it is necessary to provide a hydraulic pressure detection sensor in each hydraulic control system.

  That is, a hydraulic sensor that detects the belt narrow pressure is generally provided for feedback control. By using this, it is possible to learn and control the characteristics of the belt narrow pressure hydraulic device. In addition, in order to learn and control the line pressure control system, it is necessary to provide a new hydraulic pressure sensor for detecting the line pressure. This increases the cost and is not preferable.

  The present invention has been made to solve the above-described problems, and its purpose is to learn the relationship between the control signal and the hydraulic pressure value in the hydraulic control circuit using two linear solenoids without increasing the cost. It is possible to provide a hydraulic control device for a belt type continuously variable transmission.

  A hydraulic control device for a belt-type continuously variable transmission according to a first aspect of the invention controls a first pressure adjusting means for adjusting a discharge hydraulic pressure from an oil pump to a line pressure, and adjusts the line pressure to a belt narrow pressure hydraulic pressure. Between the control pressure to the first pressure regulating means and the line pressure, the second pressure regulating means for detecting, the detecting means for detecting the belt narrow pressure hydraulic pressure regulated by the second pressure regulating means When the storage means for previously storing and a predetermined condition are satisfied, the pressure reducing action by the second pressure regulating means is invalidated and the control signal to the first pressure regulating means is changed. And a correcting means for correcting the relationship based on the hydraulic pressure detected by the detecting means.

  According to the first invention, the storage means stores in advance the relationship between the value (duty) of the control signal to the first pressure adjusting means and the line pressure as an initial setting. When satisfying the condition that the vehicle equipped with the belt type continuously variable transmission is stopped, no major problem occurs even if the pressure regulating operation by the second pressure regulating means for regulating the belt narrow pressure hydraulic pressure is stopped. . Therefore, a state in which the line pressure reducing operation, which is a pressure adjusting operation by the second pressure adjusting means, is stopped, that is, a state in which the hydraulic pressure input to the second pressure adjusting means is output as it is. In this state, when the control signal value to the first pressure regulating means is changed, the hydraulic pressure value is usually detected by the detecting means for detecting the hydraulic pressure after the pressure regulation by the second pressure regulating means. At this time, since the second pressure adjusting unit stops the pressure adjusting operation, the oil pressure value detected by the detecting unit is the oil pressure adjusted by the first pressure adjusting unit. The relationship between the detected hydraulic pressure value and the value of the control circle is compared with the relationship stored in the storage means, and if the comparison result is different, the first adjustment is made due to individual differences or changes over time. It is determined that the relationship between the control signal value to the pressure means and the line pressure has changed, and the latest relationship is stored in the storage means for correction. In this way, there is no need to provide a line pressure sensor that directly detects the hydraulic pressure regulated by the first pressure regulating means. As a result, it is possible to provide a hydraulic control device for a belt-type continuously variable transmission that can learn the relationship between a control duty and a hydraulic value in a hydraulic control circuit using two linear solenoids without increasing costs. it can.

  In the hydraulic control apparatus for a belt type continuously variable transmission according to the second invention, in addition to the configuration of the first invention, the relationship to be corrected is the relationship between the control signal to the first pressure adjusting means and the line pressure. Correlation.

  According to the second invention, for example, if the first pressure adjusting means is a pressure reducing valve controlled by a linear solenoid, the storage means stores the correlation between the duty of the control current to the linear solenoid and the line pressure. deep. Using this correlation, the duty of the control current corresponding to the required line pressure can be accurately calculated. For this reason, in the past, when the exact correlation was unknown due to individual differences and changes over time, a higher oil pump discharge pressure was provided with a margin, and an oil pump loss occurred. Generation of excessive loss can be suppressed.

  In the hydraulic control device for a belt-type continuously variable transmission according to the third invention, in addition to the configuration of the first or second invention, the line pressure is supplied to the hydraulic chamber of the driving pulley via the switching valve, The belt narrow pressure hydraulic pressure is supplied to the hydraulic chamber of the driven pulley.

  According to the third aspect of the invention, the line pressure is supplied to the hydraulic chamber of the driving pulley, and acceleration control and deceleration control are performed, and the belt clamping hydraulic pressure is supplied to the hydraulic chamber of the driven pulley, and the necessary belt narrow pressure is obtained. Thus, the shifting operation of the belt type continuously variable transmission can be realized.

  In the hydraulic control apparatus for a belt type continuously variable transmission according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the predetermined condition is that the driving pulley and the driven pulley rotate. This is a condition that the transmission torque is not applied to the pulley in a state where the pulley is not in operation.

  According to the fourth invention, when the pulley is not rotating and no transmission torque is applied to the pulley, relative slip between the pulley and the belt does not occur. Even if the narrow pressure hydraulic pressure adjustment operation is stopped, no major problem will occur. For this reason, for example, when the shift position is the parking position, it is possible to learn the correlation between the control signal duty to the first pressure regulating means and the line pressure.

  In the hydraulic control apparatus for a belt type continuously variable transmission according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the correcting means changes the control signal to the first pressure regulating means. Means for correcting the relationship so as to match the hydraulic pressure detected by the detection means.

  According to the fifth aspect of the present invention, the correlation between the control signal duty to the first pressure adjusting means and the line pressure is made to match the actually detected hydraulic pressure value, and the desired line is taken into consideration in consideration of individual differences and changes over time. The control duty can be determined so that the pressure can be developed.

  In the hydraulic control apparatus for a belt-type continuously variable transmission according to the sixth invention, in addition to the configuration of any one of the first to fourth inventions, the correcting means changes the control signal to the first pressure regulating means. And means for correcting the relationship based on the hydraulic pressure discretely detected by the detection means and the value calculated by interpolating the discrete hydraulic pressure.

  According to the sixth aspect of the invention, the line pressure with respect to the control signal duty is detected and detected at several points, and between those points is not detected by the hydraulic sensor, but interpolation processing such as linear interpolation is performed. The correlation between the control signal duty to the pressure adjusting means and the line pressure can be calculated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a power train of a vehicle including a control device according to the present embodiment will be described. The hydraulic control apparatus according to the present embodiment is applied to the power train shown in FIG. In describing the hydraulic circuit of the hydraulic control unit 1100, the power train will be described first.

  As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, a forward / reverse switching device 290, a belt-type continuously variable transmission (CVT) 300, a differential gear 800, The ECU (Electronic Control Unit) 1000 and a hydraulic control unit 1100 are included.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft rotational speed NE (engine rotational speed NE) of engine 100 detected by the engine rotational speed sensor and input shaft rotational speed (pump rotational speed) of torque converter 200 are the same.

  The torque converter 200 includes a lock-up clutch 210 that directly connects the input shaft and the output shaft, a pump impeller 220 on the input shaft side, a turbine impeller 230 on the output shaft side, and a one-way clutch 250. It is comprised from the stator 240 which expresses an amplification function. Torque converter 200 and CVT 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by the turbine rotational speed sensor 400.

  CVT 300 is connected to torque converter 200 via forward / reverse switching device 290. The CVT 300 includes an input side primary pulley 500, an output side secondary pulley 600, and a metal belt 700 wound around the primary pulley 500 and the secondary pulley 600. Primary pulley 500 includes a fixed sheave fixed to the primary shaft and a movable sheave supported on the primary shaft so as to be slidable only. The secondary pulley 600 includes a fixed sheave fixed to the secondary shaft and a movable sheave supported by the secondary shaft so as to be slidable only. The primary pulley rotational speed NIN of the CVT 300 is detected by the primary pulley rotational speed sensor 410, and the secondary pulley rotational speed NOUT is detected by the secondary pulley rotational speed sensor 420.

  These rotation speed sensors are provided so as to face the teeth of the rotation detection gear attached to the rotation shafts of the primary pulley and the secondary pulley and the drive shaft connected thereto. These rotational speed sensors are sensors that can detect slight rotations of the primary pulley that is the input shaft and the secondary pulley that is the output shaft of the CVT 300. For example, a magnetoresistor generally referred to as a semiconductor sensor It is a sensor using an element.

  The forward / reverse switching device 290 includes a double pinion planetary gear, a reverse (reverse) brake B1 and an input clutch C1. In the planetary gear, its sun gear is connected to the input shaft, the carrier CR supporting the first and second pinions P1, P2 is connected to the primary side fixed sheave, and the ring gear R is a reverse friction engagement element. The reverse brake B1 is connected, and an input clutch C1 is interposed between the carrier CR and the ring gear R. The input clutch 310 is also called a forward clutch or a forward clutch, and is always used in an engaged state when a vehicle other than the parking (P) position, the R position, and the N position moves forward.

  The ECU 1000 and the hydraulic control unit 1100 that control these power trains will be described with reference to FIG.

  As shown in FIG. 2, ECU 1000 has a signal representing turbine rotational speed NT from turbine rotational speed sensor 400, and a signal representing primary pulley rotational speed NIN from primary pulley rotational speed sensor 410 is received from secondary pulley rotational speed sensor 420. Signals representing secondary pulley rotation speed NOUT are input.

  As shown in FIGS. 1 and 2, the hydraulic control unit 1100 includes a shift speed control unit 1110, a belt clamping pressure control unit 1120, a line pressure control unit 1122, a lockup engagement pressure control unit 1130, a clutch pressure. A control unit 1140 and a manual valve 1150 are included. From the ECU 1000, a shift control duty solenoid (1) 1200, a shift control duty solenoid (2) 1210, a belt clamping pressure control linear solenoid (SLS) 1220, and a line pressure control linear solenoid (from the ECU 1000) SLT) 1222, lockup solenoid 1230, and lockup engagement pressure control duty solenoid 1240.

  The structure of ECU 1000 that controls these power trains will be described in more detail with reference to FIG. As shown in FIG. 2, ECU 1000 includes an engine control computer 1010 that controls engine 100 and a transmission control computer 1020 that controls CVT 300.

  In addition to the input / output signals shown in FIG. 1, the transmission control computer 1020 receives a stop lamp switch, a signal indicating that the brake pedal is being depressed by the driver, and a G sensor from which the vehicle stops on an uphill road or the like. Each of the signals indicating the slope of the uphill road is input. Further, the engine control computer 1010 includes an accelerator opening sensor, a signal indicating the opening of the accelerator being stepped on by the driver, a throttle position sensor, a signal indicating the opening of the electromagnetic throttle, an engine speed sensor, Signals representing the rotational speed (NE) of engine 100 are input. Engine control computer 1010 and transmission control computer 1020 are connected to each other.

  In hydraulic control unit 1100, belt clamping pressure control unit 1120 controls the clamping pressure of belt 700 of CVT 300 based on a control signal output from transmission control computer 1020 to linear solenoid (SLS) 1220 for belt clamping pressure control. At the same time, the clutch pressure control unit 1140 controls the engagement pressure of the input clutch 310.

  Further, in the hydraulic pressure control unit 1100, based on the control signal output from the transmission control computer 1020 to the linear solenoid for line pressure control (SLT) 1222, the line pressure control unit 1122 determines the hydraulic pressure discharged from the oil pump as desired. Control to line pressure.

  A part of the hydraulic control unit 1100 shown in FIG. 1 is shown in FIG. A hydraulic circuit including important components of the hydraulic control apparatus according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 3, the hydraulic circuit includes an oil pan 2000, an oil pump 2020 that sucks and discharges oil from the oil pan 2000 via a strainer 2010, and a relief valve that reduces the hydraulic pressure discharged from the oil pump 2020 ( Pressure-reducing valve) 2222, a linear solenoid for line pressure control (SLT) 1222 for controlling the relief valve (pressure-reducing valve) 2222 so as to obtain a desired line pressure based on a control signal from the transmission control computer 1020, and the line pressure A relief valve (pressure reducing valve) 2220 for reducing pressure, and a linear solenoid (SLS) for narrow pressure control for controlling the relief valve (pressure reducing valve) 2220 so as to obtain a desired belt narrow pressure based on a control signal from the transmission control computer 1020 1220 and WD Side of the primary pulley hydraulic chamber and includes a three-way valve 2040 that is connected to a drain pipe, a hydraulic sensor 2030 for detecting the oil pressure value supplied to the secondary pulley fluid pressure chamber of the driven side. Thus, a hydraulic pressure sensor for detecting the discharge pressure from the oil pump 2020 and the line pressure is not provided.

  The three-way selector valve 2040 includes a line pressure supply port, a drain, and a speed increasing solenoid 2042 corresponding to the shift control duty solenoid (1) 1200 and a speed reducing solenoid 2044 corresponding to the speed control duty solenoid (2) 1210. The conduction / non-conduction of the output port to the port and the primary pulley hydraulic chamber is switched.

  When the acceleration side solenoid 2042 is in the ON state, the line pressure and the primary pulley hydraulic chamber are brought into conduction, and the line pressure is supplied to the primary pulley hydraulic chamber. When the deceleration side solenoid 2044 is in the ON state, the primary pulley hydraulic chamber and the drain port 2046 are in a conductive state, and the hydraulic oil is discharged from the primary pulley hydraulic chamber.

  Referring to FIG. 4, a control structure of a program executed by transmission control computer 1020 of ECU 1000 according to the present embodiment will be described using a flowchart.

  In step (hereinafter, step is abbreviated as S), transmission control computer 1020 determines whether or not the oil pump discharge pressure learning flag is ON. For example, when the vehicle shift position is the parking position and a predetermined period has elapsed since the previous learning, the oil pump discharge pressure learning flag is turned on. If the oil pump discharge pressure learning flag is ON (YES in S100), the process proceeds to S110. Otherwise (NO in S100), this process ends.

  In S110, transmission control computer 1020 outputs hydraulic pressure command value P (OUT) (= P (L) + α: α is a positive value) to narrow pressure control linear solenoid (SLS) 1220. At this time, for example, when a command value is output as a current value, a current value 0 is output as a hydraulic pressure command value.

  In S120, transmission control computer 1020 sweeps and outputs the hydraulic pressure command value of linear solenoid (SLT) 1222 for line pressure control. For example, at this time, the sweep is performed from 0 [A] to 1.0 [A]. In S130, transmission control computer 1020 detects a hydraulic pressure value P (L) of the line pressure detected by hydraulic sensor 2030. At this time, since the hydraulic pressure command value P (OUT) (= P (L) + α) is output to the narrow pressure control linear solenoid (SLS) 1220, the hydraulic pressure detected by the hydraulic sensor 2030 is the hydraulic pressure of the line pressure. It becomes the value P (L).

  At S140, transmission control computer 1020 stores line pressure P (L), which is the detected hydraulic pressure value, in the memory. At this time, in order to reduce the amount of data, a discrete line pressure P (L) may be stored. When the discrete line pressure P (L) is stored, a continuous relationship is calculated using an interpolation method such as linear interpolation.

  In S150, transmission control computer 1020 compares the map stored in the memory with the line pressure P (L) stored in S140 to determine whether map correction is necessary. If the deviation is too large, it is determined that map correction is necessary. If map correction is necessary (YES in S150), the process proceeds to S160. Otherwise (NO in S150), this process ends without correcting the map.

  In S160, transmission control computer 1020 corrects the map that defines the relationship between the control current value of linear solenoid for line pressure control (SLT) 1222 and the detected line pressure P (L).

  An operation of map learning in the vehicle including the control device according to the present embodiment based on the above-described structure and flowchart will be described.

  When the vehicle is running and the shift position is changed to the parking position and a predetermined time has elapsed since the previous learning, the oil pump discharge pressure learning flag is set to ON. When this oil pump discharge pressure learning flag is ON (YES in S100), hydraulic pressure command value P (OUT) (= P (L) + α) is output to narrow pressure control linear solenoid (SLS) 1220. That is, a control signal that is higher than the line pressure P (L) is output to the narrow pressure control linear solenoid (SLS) 1220 (S110). At this time, the narrow pressure control linear solenoid (SLS) 1220 does not reduce the hydraulic pressure input to the relief valve (pressure reducing valve) 2220.

  The hydraulic pressure command value of the line pressure control linear solenoid (SLT) 1222 is swept from 0 [A] to 1.0 [A] and output (S120). The oil pressure value detected by the oil pressure sensor 2030 at this time is the line pressure P (L) (S130). The detected line pressure P (L) is stored in the memory (S140). The difference between the control current value of the linear solenoid for line pressure control (SLT) 1222 stored in the memory and the relationship between the detected line pressure P (L) and the latest detected map is too large. If it is larger, it is determined that map correction is necessary (YES in S150), and the relationship between the control current value of the linear solenoid for line pressure control (SLT) 1222 and the detected line pressure P (L) is defined. Correct the map. At this time, as shown in FIG. 5, the detected line pressure P (L) may be detected larger or smaller than the set line pressure. In any case, the set line pressure is switched to a map representing the relationship between the control current value of the most recent line pressure control linear solenoid (SLT) 1222 and the line pressure P (L).

  By using the corrected map, the control current value of the line pressure control linear solenoid (SLT) 1222 for expressing the line pressure necessary for the shift control of the belt type continuously variable transmission can be accurately calculated. Conventionally, the map itself has changed due to individual differences and changes over time, and in order to ensure the necessary line pressure, the discharge pressure of the oil pump has tended to increase so that the line pressure becomes higher. In such a case, loss of the oil pump occurs. Since learning correction is performed so as to obtain an accurate map, such a pump loss of the oil pump does not occur. Further, in order to perform such learning control, when the narrow pressure control linear solenoid (SLS) is not operating and a hydraulic pressure sensor that detects the narrow pressure hydraulic pressure is used, the number of hydraulic pressure sensors is increased. In other words, the relationship between the control duty and the hydraulic pressure value in the hydraulic control circuit with two linear solenoids can be learned without increasing the cost.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a control block diagram of an automatic transmission to which a hydraulic control circuit according to an embodiment of the present invention is applied. FIG. 2 is a detailed view of the ECU shown in FIG. 1. It is a figure which shows the hydraulic control circuit which concerns on embodiment of this invention. It is a flowchart which shows the control structure of the program performed by ECU shown in FIG. It is a figure for demonstrating the state corrected by learning.

Explanation of symbols

  100 engine, 200 torque converter, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 240 stator, 250 one-way clutch, 290 forward / reverse switching device, 300 belt type continuously variable transmission, 310 input clutch, 400 turbine rotation Number sensor, 410 primary pulley rotation number sensor, 420 secondary pulley rotation number sensor, 500 primary pulley, 600 secondary pulley, 700 belt, 800 differential gear, 1000 ECU, 1010 engine control computer, 1020 transmission control computer, 1100 hydraulic control unit, 1110 Shift speed control unit, 1120 Belt clamping pressure control unit, 1130 Lock-up engagement pressure control unit, 114 Clutch pressure control unit, 1150 Manual valve, 1200 Shift control duty solenoid (1), 1210 Shift control duty solenoid (2), 1220 Belt clamping pressure control linear solenoid (SLS), 1222 Line pressure control linear solenoid (SLT) ) 1230 Lock-up solenoid, 1240 Duty solenoid for lock-up engagement pressure control, 2000 Oil pan, 2010 Strainer, 2020 Oil pump, 2030 Pressure sensor, 2040 Three-way selector valve, 2042 Speed-up side solenoid, 2044 Deceleration-side solenoid, 2046 Drain port.

Claims (6)

A hydraulic control device for a belt-type continuously variable transmission including a driving pulley and a driven pulley,
First pressure adjusting means for adjusting the discharge hydraulic pressure from the oil pump to a line pressure having a value corresponding to a given control signal ;
A second pressure regulating means for regulating the line pressure to a belt narrow pressure hydraulic pressure;
Detecting means for detecting the belt narrow pressure hydraulic pressure regulated by the second pressure regulating means;
Storage means for storing in advance a first relationship indicating a correspondence relationship between the control signal and the line pressure when the control signal is applied to the first pressure adjusting device;
When the condition that the driving pulley and the driven pulley is in the state not rotated is satisfied, changing the previous SL control signal while disabling the action of vacuum by the second pressure regulating means that the learning control is executed, the to approach said control signal in the learning control and the first relationship to a second relationship showing a correspondence relationship between hydraulic and detected by the detection means, the first relationship A hydraulic control device for a belt-type continuously variable transmission, including correction means for correcting The first relationship is the correlation between the control signal and the line pressure when given the control signal to the first pressure regulating means, according to claim 1 of the belt-type continuously variable transmission Hydraulic control device. The line pressure is supplied to the hydraulic chamber of the drive pulley through the switching valve,
The belt Sema圧hydraulic pressure, the pressure supplied to the hydraulic chamber of the driven pulley, the hydraulic control device for a belt type continuously variable transmission according to claim 1 or 2. Wherein the correction means, in addition to the condition that the driving pulley and the driven pulley is in a non-rotating state, the condition that torque transmitted to the drive pulley and the driven pulley is not energized satisfied The hydraulic control device for a belt type continuously variable transmission according to any one of claims 1 to 3 , wherein the learning control is executed when the learning is performed . 5. The belt-type device according to claim 1 , wherein the correction means includes means for correcting the first relationship so that the first relationship matches the second relationship. Hydraulic control device for step transmission. The correcting means corrects the first relationship based on a hydraulic pressure discretely detected by the detecting means during the learning control and a value calculated by interpolating the discrete hydraulic pressure. A hydraulic control device for a belt-type continuously variable transmission according to any one of claims 1 to 4.

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