JP2009121632A - Control device of belt-type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate which failure it is, failure of a linear solenoid SLT for controlling line pressure or failure of a linear solenoid SLS for controlling belt clamping force. <P>SOLUTION: This control device is provided for controlling a belt-type continuously variable transmission by using a hydraulic control circuit having the linear solenoid SLT for controlling the line pressure and the linear solenoid SLS for controlling the belt clamping force, and has a means for determining the existence of belt sliding based on its arithmetically operated gear ratio by arithmetically operating the gear ratio between a primary pulley and a secondary pulley, and determines that the linear solenoid SLS for controlling the belt clamping force causes failure when there is the belt sliding when input torque Nin to the primary pulley is small (Nin<a determining value C), and determines that the linear solenoid SLT for controlling the line pressure causes failure when there is the belt sliding when the input torque Nin is large (Nin≥the determining value C). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a belt type continuously variable transmission mounted on a vehicle.

  In a vehicle equipped with an engine, the gear ratio between the engine and the drive wheel is automatically set optimally as a transmission that properly transmits the torque and rotation speed generated by the engine to the drive wheel according to the running state of the vehicle. Automatic transmissions are known.

  As an automatic transmission mounted on a vehicle, for example, a planetary gear type transmission that sets a gear ratio (gear ratio) using a friction engagement element such as a clutch and a brake and a planetary gear device, or a gear ratio is not used. There is a continuously variable transmission (CVT) that adjusts in stages.

  Belt type continuously variable transmissions have a belt wound around a primary pulley (input pulley) and a secondary pulley (output pulley) that have pulley grooves (V grooves), and the width of the pulley groove of one pulley is increased. At the same time, by narrowing the width of the pulley groove of the other pulley, the belt winding radius (effective diameter) for each pulley is continuously changed to set the transmission ratio steplessly. ing. The torque transmitted in this belt type continuously variable transmission is a torque corresponding to the load acting in the direction in which the belt and the pulley come into contact with each other. Therefore, the belt is clamped by the pulley so as to apply tension to the belt. Yes.

  Further, as described above, the belt type continuously variable transmission is changed by enlarging or reducing the width of the pulley groove. Specifically, each of the primary pulley and the secondary pulley is constituted by a fixed sheave and a movable sheave, and the movable sheave is moved back and forth in the axial direction by a hydraulic actuator provided on the back side thereof to perform speed change.

  In such a belt type continuously variable transmission, for example, as described in Patent Document 1 below, the speed ratio is controlled using an upshift transmission control valve and a downshift transmission control valve. Line pressure is supplied to these two shift control valves as the original pressure.

  A duty solenoid valve (hereinafter referred to as a duty solenoid) is connected to the upshift transmission control valve and the downshift transmission control valve, and the upshift transmission control valve and the downshift according to the control hydraulic pressure output by the duty solenoid. The shift shift control valve is switched, and the amount of oil supplied to the primary pulley hydraulic actuator via the upshift shift control valve and the amount of oil discharged from the primary pulley hydraulic actuator via the downshift shift control valve And are controlled. In this way, by controlling the hydraulic pressure of the hydraulic actuator of the primary pulley, the groove width of the primary pulley, that is, the winding radius of the belt on the primary pulley side is changed to control the transmission ratio.

  A belt clamping pressure control valve is connected to the hydraulic actuator of the secondary pulley. A line pressure is supplied to the belt clamping pressure control valve, and the control pressure output from the linear solenoid (hereinafter referred to as a linear solenoid) SLS is controlled as a pilot pressure and supplied to the hydraulic actuator of the secondary pulley. The belt clamping pressure is controlled.

  The line pressure used for the above shift control and belt clamping pressure control is generated by adjusting the hydraulic pressure generated by the oil pump with the line pressure control valve (primary regulator valve). The line pressure control valve is configured to operate using a control hydraulic pressure output from a linear solenoid valve (hereinafter referred to as a linear solenoid) SLT for line pressure control as a pilot pressure.

  In such a belt type continuously variable transmission, for example, the presence or absence of belt slip is determined from the gear ratio at the start of the vehicle (the gear ratio between the primary pulley and the secondary pulley), and the belt slip occurs. When it is, it is determined that a failure has occurred in a part such as a linear solenoid.

  In addition, there exists a technique of the following patent document 2 as a technique regarding the failure determination of a belt-type continuously variable transmission. In the technique described in Patent Document 2, a gear ratio detection unit that detects a gear ratio between a driving pulley and a driven pulley, and a torque detection unit that detects torque (engine torque) input to the driving pulley. Are used to detect the gear ratio and the engine torque after starting after the vehicle stops, and determine the failure of at least one of the drive side control valve and the driven side control valve based on the detected gear ratio and engine torque. .

Patent Document 3 below discloses a technique for determining a slip state of a belt of a continuously variable transmission based on a vibration state of the belt.
JP 2007-177833 A JP 2004-263714 A JP 2001-108082 A

  By the way, when the belt-type continuously variable transmission is controlled by the hydraulic control circuit having the linear solenoid SLT for controlling the line pressure and the linear solenoid SLS for controlling the belt clamping pressure as described above, the linear solenoid SLT or the linear solenoid SLT Even if one of the solenoids SLS fails, the belt clamping pressure is insufficient and belt slippage occurs. Such a linear solenoid failure can be determined by the gear ratio at the start of the vehicle as described above. However, it is impossible to determine which of the linear solenoid SLT and the linear solenoid SLS is out of order by determining only the gear ratio.

  Patent Document 2 describes a technique for determining failure of the drive side control valve and the driven side control valve. However, the line pressure is controlled using the linear solenoid SLT, and the belt clamping is performed using the linear solenoid SLS. In the control system for controlling the pressure, there is no suggestion regarding a problem that occurs when a linear solenoid fails (failure linear solenoid cannot be identified).

  The present invention has been made in consideration of such circumstances, and a belt-type continuously variable transmission using a hydraulic control circuit having a linear solenoid SLT for line pressure control and a linear solenoid SLS for belt clamping pressure control. An object of the present invention is to provide a technique capable of specifying a linear solenoid in which a failure has occurred when either one of the linear solenoid SLT or the linear solenoid SLS fails.

  The present invention relates to a primary pulley and a secondary pulley, a belt wound around the primary pulley and the secondary pulley, a hydraulic actuator for changing the groove width of the primary pulley, and a hydraulic actuator for changing the groove width of the secondary pulley. A linear pressure control linear solenoid, and a belt clamping pressure control linear solenoid that controls a line pressure supplied to the hydraulic actuator of the secondary pulley. It is premised on a control device for a belt-type continuously variable transmission. In such a belt type continuously variable transmission control device, belt slip determination means for determining the presence or absence of belt slip of the belt type continuously variable transmission, and input torque calculation for calculating input torque to the primary pulley If the belt slippage occurs when the input torque is less than the determination value, it is determined that the belt clamping pressure control linear solenoid is malfunctioning, and the belt slippage occurs when the input torque is equal to or greater than the determination value. If there is, a failure determination means for determining that the line pressure control linear solenoid is faulty is provided.

  In the present invention, as a method for determining the presence or absence of belt slip, for example, a method of calculating a gear ratio between a primary pulley and a secondary pulley and determining the presence or absence of belt slip on the basis of the calculated gear ratio. Can do. In this case, a value larger than the maximum gear ratio of the belt-type continuously variable transmission (low-side value) is used as a determination value, and it is determined that “belt slippage exists” when the calculated gear ratio is equal to or greater than the determination value. .

  Further, the determination value set for the input torque is larger than the transmission torque capacity when the belt clamping pressure control linear solenoid fails and smaller than the transmission torque capacity when the line pressure control linear solenoid fails. A value (torque) may be set.

  According to the present invention, when a failure occurs in either the line pressure control linear solenoid or the belt clamping pressure control linear solenoid, the linear solenoid in which the failure has occurred can be identified. This will be described below.

  First, in the control to which the present invention is applied, the hydraulic pressure generated by the oil pump is regulated by a line pressure control valve that operates according to the output control hydraulic pressure of the linear solenoid SLT (normally open type) to generate the line pressure PL, The line pressure PL is supplied to the belt clamping pressure control valve. In the belt clamping pressure control valve, the belt clamping pressure is controlled by adjusting the line pressure PL using the control hydraulic pressure output from the linear solenoid SLS (normally open type) as a pilot pressure and supplying it to the hydraulic actuator of the secondary pulley. is doing.

  In such a control system, when the linear solenoid SLT malfunctions, the line pressure control valve is set to the closed side, and the line pressure PL is fixed to the minimum required hydraulic pressure PLmin. In addition, when the linear solenoid SLS has an ON failure, the belt clamping pressure control valve is set to the closed side, and is fixed to the hydraulic pressure PBmin for ensuring the minimum belt clamping pressure. However, the hydraulic pressure PLmin that is fixed when the linear solenoid SLT has an ON failure is the hydraulic pressure that is fixed when the linear solenoid SLS has an ON failure because the line pressure PL is used for purposes other than the belt clamping pressure control. It is set larger than PBmin (PLmin> PBmin).

  Accordingly, when the linear solenoid SLS for controlling the belt clamping pressure is normal and the linear solenoid SLT for controlling the line pressure is out of order, the belt clamping pressure is determined by the hydraulic pressure PLmin. On the other hand, when the linear solenoid SLT for controlling the line pressure is normal and the linear solenoid SLS for controlling the belt clamping pressure is out of order, the belt clamping pressure is determined by the hydraulic pressure PBmin (PBmin <PLmin). Compared to the case where the solenoid SLT is out of order, the belt clamping pressure is reduced, and the torque capacity that can be transmitted is reduced (see FIG. 8). In other words, when the linear solenoid SLS for controlling the belt clamping pressure is out of order, the belt slip occurs with a smaller input torque than when the linear solenoid SLT for controlling the line pressure is out of order. .

  From the above, when there is a belt slip when the input torque to the primary pulley is small (specifically, input torque <determination value), the linear solenoid on the side with the smaller torque capacity, that is, the belt clamp It can be determined that the linear solenoid SLS for pressure control is out of order. On the other hand, when there is a belt slip when the input torque to the primary pulley is large (specifically, input torque ≧ determination value), the linear solenoid on the side having a large torque capacity that can be secured at the time of ON failure, that is, for line pressure control It can be determined that the linear solenoid SLT has failed.

  The input torque to the primary pulley can be calculated based on, for example, engine torque, torque converter torque ratio, input inertia torque, and the like.

  According to the present invention, in a control device for controlling a belt-type continuously variable transmission using a hydraulic control circuit having a linear solenoid SLT for controlling line pressure and a linear solenoid SLS for controlling belt clamping pressure, the linear solenoid SLT is used. Alternatively, when a failure occurs in any one of the linear solenoids SLS, the linear solenoid in which the failure has occurred can be identified, so that maintainability can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a vehicle to which the present invention is applied.

  The vehicle in this example is an FF (front engine / front drive) type vehicle, which is an engine (internal combustion engine) 1 that is a driving power source, a torque converter 2 as a fluid transmission device, a forward / reverse switching device 3, a belt type. A continuously variable transmission (CVT) 4, a reduction gear device 5, a differential gear device 6, an ECU (Electronic Control Unit) 8, and the like are mounted. The ECU 8, a hydraulic control circuit 20, which will be described later, and a primary pulley rotational speed A control device for the belt type continuously variable transmission is realized by the sensor 105, the secondary pulley rotation speed sensor 106, and the like.

  A crankshaft 11, which is an output shaft of the engine 1, is connected to the torque converter 2, and the output of the engine 1 is transmitted from the torque converter 2 through the forward / reverse switching device 3, the belt type continuously variable transmission 4, and the reduction gear device 5. Are transmitted to the differential gear device 6 and distributed to the left and right drive wheels (not shown).

  The parts of the engine 1, the torque converter 2, the forward / reverse switching device 3, the belt-type continuously variable transmission 4, and the ECU 8 will be described below.

-Engine-
The engine 1 is a multi-cylinder gasoline engine, for example. The amount of intake air taken into the engine 1 is adjusted by an electronically controlled throttle valve 12. The throttle valve 12 can electronically control the throttle opening independently of the driver's accelerator pedal operation, and the opening (throttle opening) is detected by the throttle opening sensor 102. Further, the coolant temperature of the engine 1 is detected by a water temperature sensor 103.

  The throttle opening of the throttle valve 12 is driven and controlled by the ECU 8. Specifically, the optimum intake air amount (in accordance with the operating state of the engine 1 such as the engine speed Ne detected by the engine speed sensor 101 and the accelerator pedal depression amount (accelerator operation amount Acc) of the driver). The throttle opening of the throttle valve 12 is controlled so as to obtain a target intake air amount. More specifically, the actual throttle opening of the throttle valve 12 is detected using the throttle opening sensor 102, and the actual throttle opening coincides with the throttle opening (target throttle opening) at which the target intake air amount can be obtained. Thus, the throttle motor 13 of the throttle valve 12 is feedback-controlled.

-Torque converter-
The torque converter 2 includes an input-side pump impeller 21, an output-side turbine runner 22, a stator 23 that develops a torque amplification function, and the like, and fluid is supplied between the pump impeller 21 and the turbine runner 22. Transmit power. The pump impeller 21 is connected to the crankshaft 11 of the engine 1. The turbine runner 22 is connected to the forward / reverse switching device 3 via the turbine shaft 27.

  The torque converter 2 is provided with a lockup clutch 24 that directly connects the input side and the output side of the torque converter 2. The lock-up clutch 24 controls the differential pressure (lock-up differential pressure) between the hydraulic pressure in the engagement side oil chamber 25 and the hydraulic pressure in the release side oil chamber 26 to achieve full engagement and half engagement (in the slip state). Engagement) or release.

  By completely engaging the lockup clutch 24, the pump impeller 21 and the turbine runner 22 rotate integrally. Further, by engaging the lockup clutch 24 in a predetermined slip state (half-engaged state), the turbine runner 22 rotates following the pump impeller 21 with a predetermined slip amount during driving. On the other hand, by setting the lockup differential pressure to be negative, the lockup clutch 24 is released.

  The torque converter 2 is provided with a mechanical oil pump (hydraulic pressure generating source) 7 that is connected to and driven by the pump impeller 21.

-Forward / reverse switching device-
The forward / reverse switching device 3 includes a double pinion type planetary gear mechanism 30, a forward clutch (input clutch) C1, and a reverse brake B1.

  The sun gear 31 of the planetary gear mechanism 30 is integrally connected to the turbine shaft 27 of the torque converter 2, and the carrier 33 is integrally connected to the input shaft 40 of the belt type continuously variable transmission 4. The carrier 33 and the sun gear 31 are selectively connected via the forward clutch C1, and the ring gear 32 is selectively fixed to the housing via the reverse brake B1.

  The forward clutch C1 and the reverse brake B1 are hydraulic friction engagement elements that are engaged and released by a hydraulic control circuit 20 to be described later. The forward clutch C1 is engaged and the reverse brake B1 is released. Thus, the forward / reverse switching device 3 is integrally rotated to establish (achieve) the forward power transmission path, and in this state, the forward driving force is transmitted to the belt-type continuously variable transmission 4 side. .

  On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 3 establishes (achieves) a reverse power transmission path. In this state, the input shaft 40 rotates in the reverse direction with respect to the turbine shaft 27, and the driving force in the reverse direction is transmitted to the belt type continuously variable transmission 4 side. Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 3 becomes neutral (interrupted state) for interrupting power transmission.

-Belt type continuously variable transmission-
The belt-type continuously variable transmission 4 includes an input-side primary pulley 41, an output-side secondary pulley 42, a metal belt 43 wound around the primary pulley 41 and the secondary pulley 42, and the like.

  The primary pulley 41 is a variable pulley having a variable effective diameter, and a fixed sheave 411 fixed to the input shaft 40 and a movable sheave 412 disposed on the input shaft 40 in a state in which sliding is possible only in the axial direction. It is constituted by. Similarly, the secondary pulley 42 is a variable pulley whose effective diameter is variable, and is a fixed sheave 421 fixed to the output shaft 44 and a movable sheave arranged on the output shaft 44 so as to be slidable only in the axial direction. 422.

  A hydraulic actuator 413 for changing the V groove width between the fixed sheave 411 and the movable sheave 412 is disposed on the movable sheave 412 side of the primary pulley 41. Similarly, a hydraulic actuator 423 for changing the V groove width between the fixed sheave 421 and the movable sheave 422 is also arranged on the movable sheave 422 side of the secondary pulley 42.

  In the belt type continuously variable transmission 4 having the above-described structure, by controlling the hydraulic pressure of the hydraulic actuator 413 of the primary pulley 41, the V groove widths of the primary pulley 41 and the secondary pulley 42 change, and the engagement diameter of the belt 43 ( The effective gear ratio) is changed, and the gear ratio γ (γ = primary pulley rotation speed (input shaft rotation speed) Nin / secondary pulley rotation speed (output shaft rotation speed) Nout) continuously changes. The hydraulic pressure of the hydraulic actuator 423 of the secondary pulley 42 is controlled such that the belt 43 is clamped with a predetermined clamping pressure that does not cause belt slip. These controls are executed by the ECU 8 and the hydraulic control circuit 20.

-Hydraulic control circuit-
As shown in FIG. 1, the hydraulic control circuit 20 includes a shift speed control unit 20a, a belt clamping pressure control unit 20b, a line pressure control unit 20c, a lockup engagement pressure control unit 20d, a clutch pressure control unit 20e, and a manual control unit. It is constituted by a valve 20f or the like.

  Further, the duty solenoid (DS1) 304 and the duty solenoid (DS2) 305 for controlling the shift speed, the linear solenoid (SLS) 202 for controlling the belt clamping pressure, and the linear solenoid (SLT) for controlling the line pressure are included in the hydraulic control circuit 20. ) 201 and a control signal from the ECU 8 are supplied to a duty solenoid (DSU) 307 for controlling the lock-up engagement pressure.

  Next, in the hydraulic control circuit 20, the hydraulic control circuit of the hydraulic actuator 413 of the primary pulley 41 of the belt-type continuously variable transmission 4 (specific hydraulic circuit configuration of the transmission speed control unit 20 a), and the secondary pulley 42 A hydraulic control circuit of the hydraulic actuator 423 (specific hydraulic circuit configuration of the belt clamping pressure control unit 20b) will be described with reference to FIGS.

  First, as shown in FIG. 3, the hydraulic pressure generated by the oil pump 7 is regulated by the primary regulator valve 203 to generate the line pressure PL. The primary regulator valve 203 is supplied with the control hydraulic pressure output from the linear solenoid (SLT) 201 via the clutch apply control valve 204, and operates with the control hydraulic pressure as a pilot pressure.

  Note that, by switching the clutch apply control valve 204, the control hydraulic pressure from the linear solenoid (SLS) 202 is supplied to the primary regulator valve 203, and the line pressure PL may be regulated using the control hydraulic pressure as a pilot pressure. The linear solenoid (SLT) 201 and the linear solenoid (SLS) 202 are supplied with the hydraulic pressure adjusted by the modulator valve 205 using the line pressure PL as a source pressure.

  The linear solenoid (SLT) 201 outputs a control hydraulic pressure according to a current value determined by a duty signal (duty value) transmitted from the ECU 8. A linear solenoid (SLT) 201 is a normally open type solenoid valve.

  Further, the linear solenoid (SLS) 202 outputs a control hydraulic pressure according to a current value determined by a duty signal (duty value) transmitted from the ECU 8. The linear solenoid (SLS) 202 is also a normally open type solenoid valve, like the linear solenoid (SLT) 201.

  2 and 3, the modulator valve 206 adjusts the hydraulic pressure output from the modulator valve 205 to a constant pressure, and a duty solenoid (DS1) 304 and a duty solenoid (DS2) 305 described later. , And the belt clamping pressure control valve 303 and the like.

[Shift speed control]
Next, a hydraulic control circuit for the hydraulic actuator 413 of the primary pulley 41 will be described. As shown in FIG. 2, an upshift transmission control valve 301 is connected to the hydraulic actuator 413 of the primary pulley 41.

  The upshift transmission control valve 301 is provided with a spool 311 that is movable in the axial direction. A spring 312 is disposed on one end side (the upper end side in FIG. 2) of the spool 311, and a first hydraulic port 315 is formed at the end opposite to the spring 312 across the spool 311. A second hydraulic port 316 is formed on the one end side where the spring 312 is disposed.

  The first hydraulic pressure port 315 is connected to a duty solenoid (DS1) 304 that outputs a control hydraulic pressure in accordance with a current value determined by a duty signal (duty value) transmitted from the ECU 8. The duty solenoid (DS1) 304 is connected to the first hydraulic pressure port 315. Is applied to the first hydraulic pressure port 315. A duty solenoid (DS2) 305 that outputs a control hydraulic pressure according to a current value determined by a duty signal (duty value) transmitted from the ECU 8 is connected to the second hydraulic pressure port 316. The duty solenoid (DS2) 305 is connected to the second hydraulic pressure port 316. Is applied to the second hydraulic pressure port 316.

  Further, the upshift transmission control valve 301 is formed with an input port 313 to which the line pressure PL is supplied, an input / output port 314 and an output port 317 that are connected (communication) to the hydraulic actuator 413 of the primary pulley 41. When the spool 311 is in the upshift position (the right position in FIG. 2), the output port 317 is closed, and the line pressure PL is supplied from the input port 313 to the hydraulic actuator 413 of the primary pulley 41 via the input / output port 314. . On the other hand, when the spool 311 is in the closed position (the left position in FIG. 2), the input port 313 is closed, and the hydraulic actuator 413 of the primary pulley 41 communicates with the output port 317 via the input / output port 314.

  The downshift transmission control valve 302 is provided with a spool 321 that is movable in the axial direction. A spring 322 is disposed on one end side (the lower end side in FIG. 2) of the spool 321 and a first hydraulic port 326 is formed on one end side thereof. A second hydraulic port 327 is formed at the end opposite to the spring 322 across the spool 321. The duty solenoid (DS1) 304 is connected to the first hydraulic pressure port 326, and the control hydraulic pressure output from the duty solenoid (DS1) 304 is applied to the first hydraulic pressure port 326. The duty solenoid (DS2) 305 is connected to the second hydraulic pressure port 327, and the control hydraulic pressure output from the duty solenoid (DS2) 305 is applied to the second hydraulic pressure port 327.

  Further, the downshift transmission control valve 302 is formed with an input port 323, an input / output port 324, and a discharge port 325. A bypass control valve 306 is connected to the input port 323, and a hydraulic pressure obtained by adjusting the line pressure PL by the bypass control valve 306 is supplied. In such a downshift transmission control valve 302, the input / output port 324 communicates with the discharge port 325 when the spool 321 is in the downshift position (left side position in FIG. 2). On the other hand, when the spool 321 is in the closed position (right side position in FIG. 2), the input / output port 324 is closed. The input / output port 324 of the downshift transmission control valve 302 is connected to the output port 317 of the upshift transmission control valve 301.

  In the hydraulic control circuit of FIG. 2 described above, when the control hydraulic pressure output from the duty solenoid (DS1) 304 is supplied to the first hydraulic port 315 of the upshift transmission control valve 301, the thrust according to the control hydraulic pressure causes The spool 311 moves to the upshift position side (upper side in FIG. 2). By the movement of the spool 311 (movement toward the upshift side), hydraulic oil (line pressure PL) is supplied from the input port 313 to the hydraulic actuator 413 of the primary pulley 41 through the input / output port 314 at a flow rate corresponding to the control hydraulic pressure. At the same time, the output port 317 is closed and the flow of hydraulic oil to the downshift transmission control valve 302 is blocked. As a result, the transmission control pressure is increased, the V groove width of the primary pulley 41 is reduced, and the transmission ratio γ is reduced (upshift).

  When the control hydraulic pressure output from the duty solenoid (DS1) 304 is supplied to the first hydraulic pressure port 326 of the downshift transmission control valve 302, the spool 321 moves upward in FIG. 2 and the input / output port 324 is closed. Is done.

  On the other hand, when the control hydraulic pressure output from the duty solenoid (DS2) 305 is supplied to the second hydraulic pressure port 316 of the upshift transmission control valve 301, the spool 311 is moved to the downshift position side (by the thrust corresponding to the control hydraulic pressure). Move to the lower side of FIG. By this movement of the spool 311 (movement toward the downshift side), the hydraulic oil in the hydraulic actuator 413 of the primary pulley 41 flows into the input / output port 314 of the upshift transmission control valve 301 at a flow rate corresponding to the control hydraulic pressure. The hydraulic fluid flowing into the upshift transmission control valve 301 is discharged from the discharge port 325 through the output port 317 and the input / output port 324 of the downshift transmission control valve 302. As a result, the transmission control pressure is reduced, the V groove width of the input side variable pulley 42 is increased, and the transmission ratio γ is increased (downshift).

  When the control hydraulic pressure output from the duty solenoid (DS2) 305 is supplied to the second hydraulic pressure port 327 of the downshift transmission control valve 302, the spool 321 moves downward in FIG. The discharge port 325 communicates.

  As described above, when the control hydraulic pressure is output from the duty solenoid (DS1) 304, hydraulic oil is supplied from the upshift transmission control valve 301 to the hydraulic actuator 413 of the primary pulley 41, and the transmission control pressure is continuously increased. Shifted. When the control hydraulic pressure is output from the duty solenoid (DS2) 305, the hydraulic oil in the hydraulic actuator 413 of the primary pulley 41 is discharged from the discharge port 325 of the downshift transmission control valve 302, and the transmission control pressure is continuously increased. Downshifted to

  In this example, as shown in FIG. 5, for example, the target rotational speed Nint on the input side is calculated from a preset shift map using the accelerator operation amount Acc representing the driver's requested output amount and the vehicle speed V as parameters, The shift control of the belt-type continuously variable transmission 4, that is, the hydraulic actuator 413 of the primary pulley 41 is controlled according to the deviation (Nint−Nin) so that the actual input shaft speed Nin matches the target speed Nint. The transmission control pressure is controlled by supplying and discharging the hydraulic oil, and the transmission ratio γ continuously changes. The map in FIG. 5 corresponds to the speed change condition and is stored in the ROM 82 (see FIG. 4) of the ECU 8.

  In the map of FIG. 5, the target rotational speed Nint is set such that the greater the vehicle speed V and the greater the accelerator operation amount Acc, the greater the gear ratio γ. Further, since the vehicle speed V corresponds to the secondary pulley rotational speed (output shaft rotational speed) Nout, the target rotational speed Nint, which is the target value of the primary pulley rotational speed (input shaft rotational speed) Nin, corresponds to the target gear ratio, It is set within the range of the minimum speed ratio γmin and the maximum speed ratio γmax of the continuously variable transmission 4.

[Belt clamping pressure control]
Next, a hydraulic control circuit of the hydraulic actuator 423 of the secondary pulley 42 will be described with reference to FIG.

  As shown in FIG. 3, a belt clamping pressure control valve 303 is connected to the hydraulic actuator 423 of the secondary pulley 42.

  The belt clamping pressure control valve 303 is provided with a spool 331 that is movable in the axial direction. A spring 332 is disposed on one end side (the lower end side in FIG. 3) of the spool 331, and a first hydraulic port 335 is formed on one end side thereof. A second hydraulic port 336 is formed at the end opposite to the spring 332 across the spool 331.

  A linear solenoid (SLS) 202 is connected to the first hydraulic pressure port 335, and a control hydraulic pressure output from the linear solenoid (SLS) 202 is applied to the first hydraulic pressure port 335. The hydraulic pressure from the modulator valve 206 is applied to the second hydraulic pressure port 336.

  Further, the belt clamping pressure control valve 303 is formed with an input port 333 to which the line pressure PL is supplied and an output port 334 connected (communication) to the hydraulic actuator 423 of the secondary pulley 42.

  In the hydraulic control circuit of FIG. 3, when the control hydraulic pressure output from the linear solenoid (SLS) 202 increases from the state where a predetermined hydraulic pressure is supplied to the hydraulic actuator 423 of the secondary pulley 42, the belt clamping pressure control valve 303 The spool 331 moves upward in FIG. In this case, the hydraulic pressure supplied to the hydraulic actuator 423 of the secondary pulley 42 increases, and the belt clamping pressure increases.

  On the other hand, when the control hydraulic pressure output from the linear solenoid (SLS) 202 decreases from the state in which the predetermined hydraulic pressure is supplied to the hydraulic actuator 423 of the secondary pulley 42, the spool 331 of the belt clamping pressure control valve 303 is lowered in FIG. Move to the side. In this case, the hydraulic pressure supplied to the hydraulic cylinder of the secondary pulley 42 decreases, and the belt clamping pressure decreases.

  In this way, the belt clamping pressure is increased or decreased by adjusting the line pressure PL using the control hydraulic pressure output from the linear solenoid (SLS) 202 as a pilot pressure and supplying it to the hydraulic actuator 423 of the secondary pulley 42.

  In this example, as shown in FIG. 6, for example, the accelerator opening Acc corresponding to the transmission torque and the gear ratio γ (γ = Nin / Nout) are used as parameters, and it is necessary to set in advance so that belt slip does not occur. By controlling the control hydraulic pressure output from the linear solenoid (SLS) 202 according to a map of hydraulic pressure (equivalent to belt clamping pressure), the belt clamping pressure of the belt-type continuously variable transmission 4, that is, the hydraulic actuator 423 of the secondary pulley 42 is controlled. This is done by controlling the pressure of the oil. The map in FIG. 6 corresponds to the clamping pressure control condition and is stored in the ROM 82 (see FIG. 4) of the ECU 8.

-ECU-
The ECU 8 includes a CPU 81, a ROM 82, a RAM 83, a backup RAM 84, and the like as shown in FIG.

  The ROM 82 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 81 executes arithmetic processing based on various control programs and maps stored in the ROM 82. The RAM 83 is a memory for temporarily storing calculation results in the CPU 81 and data input from each sensor. The backup RAM 84 is a non-volatile memory for storing data to be saved when the engine 1 is stopped. is there.

  The CPU 81, ROM 82, RAM 83, and backup RAM 84 are connected to each other via a bus 87 and are connected to an input interface 85 and an output interface 86.

  The input interface 85 of the ECU 8 includes an engine speed sensor 101, a throttle opening sensor 102, a water temperature sensor 103, a turbine speed sensor 104, a primary pulley speed sensor 105, a secondary pulley speed sensor 106, an accelerator position sensor 107, A CVT oil temperature sensor 108, a brake pedal sensor 109, a lever position sensor 110 for detecting a lever position (operation position) of the shift lever 9, and the like are connected. Output signals of the sensors, that is, rotation of the engine 1 are connected. Number (engine speed) Ne, throttle opening θth of the throttle valve 12, cooling water temperature Tw of the engine 1, turbine shaft 27 speed (turbine speed) Nt, primary pulley speed (input shaft speed) Nin, secondary Pulley rotation speed Output shaft speed Nout, accelerator pedal operation amount (accelerator degree of engagement) Acc, oil temperature of hydraulic control circuit 20 (CVT oil temperature Thc), presence / absence of operation of foot brake as a normal brake (brake ON / OFF), A signal indicating the lever position (operation position) of the shift lever 9 and the like is supplied to the ECU 8.

  The output interface 86 is connected to the throttle motor 13, the fuel injection device 14, the ignition device 15, the hydraulic control circuit 20 (lockup control circuit 200), and the like.

  Here, among the signals supplied to the ECU 8, the turbine rotational speed Nt coincides with the primary pulley rotational speed (input shaft rotational speed) Nin during forward travel in which the forward clutch C1 of the forward / reverse switching device 3 is engaged. The secondary pulley rotational speed (output shaft rotational speed) Nout corresponds to the vehicle speed V. The accelerator operation amount Acc represents the driver's requested output amount.

  The shift lever 9 includes a parking position “P” for parking, a reverse position “R” for reverse traveling, a neutral position “N” for interrupting power transmission, a drive position “D” for forward traveling, During forward running, the gear ratio γ of the belt type continuously variable transmission 4 is selectively operated to each position such as a manual position “M” where the manual operation can increase or decrease the speed ratio γ.

  The manual position “M” includes a plurality of ranges in which a downshift position and an upshift position for increasing / decreasing the speed ratio γ, or a plurality of speed ranges in which the upper limit of the speed range (the side where the speed ratio γ is smaller) are different can be selected. Position etc. are provided.

  The lever position sensor 110 is, for example, a parking position “P”, a reverse position “R”, a neutral position “N”, a drive position “D”, a manual position “M”, an upshift position, a downshift position, or a range position. A plurality of ON / OFF switches for detecting that the shift lever 9 is operated are provided. In order to change the speed ratio γ by manual operation, a downshift switch, an upshift switch, a lever, or the like can be provided on the steering wheel or the like separately from the shift lever 9.

  Then, the ECU 8 controls the output of the engine 1, the shift speed control and belt clamping pressure control of the belt-type continuously variable transmission 4, and the lock-up clutch 24 based on the output signals of the various sensors described above. Execute release / release control. Further, the ECU 8 executes a linear solenoid failure determination process described later.

  The output control of the engine 1 is executed by the throttle motor 13, the fuel injection device 14, the ignition device 15, the ECU 8, and the like.

-Linear solenoid failure judgment process-
First, in the hydraulic control circuit shown in FIGS. 2 and 3, when the linear solenoid (SLT) 201 fails in the ON state, the primary regulator valve (line pressure control valve) 203 is set to the closed side, and the line pressure PL is the minimum necessary. The oil pressure is fixed at PLmin. Further, when the linear solenoid (SLS) 202 is in an ON failure, the belt clamping pressure control valve 303 is set to the closed side, and is fixed to the hydraulic pressure PBmin for ensuring a minimum belt clamping pressure. However, the hydraulic pressure PLmin that is fixed when the linear solenoid (SLT) 201 fails to turn on, for the reason that the line pressure PL is used for other than the belt clamping pressure control, the linear solenoid (SLS) 202 is turned on. It is set larger than the oil pressure PBmin that is sometimes fixed (PLmin> PBmin).

  Therefore, when the linear solenoid (SLS) 202 for controlling the belt clamping pressure is normal and the linear solenoid (SLT) 201 for controlling the line pressure is broken, the belt clamping pressure is determined by the hydraulic pressure PLmin. On the other hand, when the linear solenoid (SLT) 201 for line pressure control is normal and the linear solenoid (SLS) 202 for belt clamping pressure is out of order, the belt clamping pressure is set by the hydraulic pressure PBmin (PBmin <PLmin). Is determined, and the belt clamping pressure is reduced as compared with the case where the linear solenoid (SLT) 201 is out of order, and the transmittable torque capacity is reduced. In other words, when the linear solenoid (SLS) 202 for controlling the belt clamping pressure is out of order, the belt slip with a smaller input torque than when the linear solenoid (SLT) 201 for controlling the line pressure is out of order. Will occur.

  Focusing on this point, in this example, if there is a belt slip when the input torque to the primary pulley 41 is small, it is determined that the line pressure control linear solenoid (SLS) 202 has failed, and the primary pulley 41 When there is a belt slip when the input torque is large, it is determined that a failure of the linear solenoid (SLT) 201 for line pressure control is detected.

  A specific example (failure determination process) will be described with reference to the flowchart of FIG. The control routine of FIG. 7 is repeatedly executed by the ECU 8 every predetermined time.

  In step ST1, it is determined whether or not a transmission ratio calculation permission condition is satisfied. Specifically, shifting is performed when the condition that the primary pulley rotation speed Nin is equal to or greater than a predetermined determination value A1 (Nin ≧ A1) and the secondary pulley rotation speed Nout is equal to or greater than a predetermined determination value A2 (Nout ≧ A2). The ratio calculation is permitted and the process proceeds to step ST2. If the determination result in step ST1 is negative, the process returns.

  The reason for executing the permission determination in step ST1 will be described. First, the primary pulley rotation speed Nin and the secondary pulley rotation speed Nout are detected using, for example, a sensor composed of a signal rotor having a plurality of teeth (projections) formed on the outer peripheral surface and an electromagnetic pickup. The number of teeth of the signal rotor used for the pulley rotational speed Nin is made larger than the number of teeth of the signal rotor used for detecting the secondary pulley rotational speed Nout. For this reason, the difference in the number of teeth of the signal rotor (difference in detection accuracy) may greatly affect the calculation gear ratio (Nin / Nout) in the low speed range, and the gear ratio may not be calculated accurately. is there. In consideration of such points, in this example, the number of revolutions (A1, A2) at which the influence of the difference in the number of teeth of the signal rotor is reduced, that is, the speed ratio (Nin / Nout) can be accurately calculated. The gear ratio calculation is permitted on the condition that the above is reached. As the determination value A1 and the determination value A2, values empirically obtained through experiments and calculations are set.

  Next, in step ST2, a speed ratio RATIO (RATIO = Nin / Nout) is calculated from the primary pulley rotational speed Nin and the secondary pulley rotational speed Nout, and the calculated speed ratio RATIO is equal to or greater than a predetermined determination value B (RATIO ≧ B). In addition, it is determined whether or not the input torque Tin to the primary pulley 41 is less than a predetermined determination value C (Tin <C).

  Here, the determination value B for the calculation gear ratio RATIO is a determination value for determining the presence or absence of the belt slip, and is set to a value lower than the gear ratio γmax of the map shown in FIG. If the condition B] is satisfied, it is determined that belt slippage has occurred in the belt type continuously variable transmission 4.

  The input torque Tin can be calculated based on the engine torque Te, the torque ratio t of the torque converter 2, and the input inertia torque. Here, the engine torque Te can be calculated from, for example, the throttle opening degree θth and the engine speed Ne. The torque ratio t is a function of [primary pulley rotational speed (input shaft rotational speed) Nin / engine rotational speed Ne], and the input inertia torque is calculated from the time variation of the primary pulley rotational speed (input shaft rotational speed) Nin. can do.

  The determination value C for the input torque Tin is a value larger than the torque capacity that can be secured by the hydraulic pressure PBmin when the belt solenoid pressure control linear solenoid (SLS) 202 is turned ON (torque causing belt slip), and the line pressure The value is smaller than the torque capacity that can be secured by the hydraulic pressure PLmin when the control linear solenoid (SLT) 201 is turned ON (torque at which the belt does not slip). Specifically, for example, as shown in FIG. 8, a value (torque) between the torque capacity at the time of ON failure of the linear solenoid (SLS) 202 and the torque capacity at the time of ON failure of the linear solenoid (SLT) 201 is determined. Set as value C.

  If the determination result in step ST2 is affirmative, that is, if the input torque Tin is less than the determination value C (Tin <C) and belt slipping has occurred, the linear solenoid that is in an ON failure has an ON failure. Since it can be identified that the linear solenoid (SLS) 202 has a lower torque capacity at times, it is determined in step ST3 that the linear solenoid (SLS) 202 has an ON failure.

  On the other hand, when the determination result of step ST2 is negative, that is, when belt slip does not occur (RATIO <B), or when the input torque Tin is greater than or equal to the determination value C even when belt slip occurs ( For Tin ≧ C), the process proceeds to step ST4.

  In step ST4, the calculation gear ratio RATIO calculated from the primary pulley rotation speed Nin and the secondary pulley rotation speed Nout is not less than the determination value B (RATIO ≧ B), and the input torque Tin is not less than the determination value C (Tin ≧). C).

  If the determination result in step ST4 is affirmative, that is, if the input torque Tin is equal to or greater than the determination value C (Tin ≧ C) and belt slipping occurs, a linear solenoid that is in an ON failure is secured when the ON failure occurs. Since it can be specified that the linear solenoid (SLT) 201 has a larger torque capacity, it is determined in step ST5 that the linear solenoid (SLT) 201 has an ON failure.

  If both the determination results of step ST2 and step ST4 are negative, that is, if no belt slip has occurred, it is determined to be normal, and this routine is temporarily terminated.

  As described above, according to the linear solenoid failure determination process in this example, a failure has occurred in either the linear solenoid (SLT) 201 for line pressure control or the linear solenoid (SLS) 202 for belt clamping pressure control. Sometimes it is possible to identify the linear solenoid in which the failure occurred. As a result, for example, it is only necessary to perform processing such as replacing only the linear solenoid (SLT) 201 or the linear solenoid (SLS) 202 in which a failure has occurred, so that maintainability is improved.

-Other embodiments-
In the above example, the example in which the present invention is applied to the shift control of a belt type continuously variable transmission of a vehicle equipped with a gasoline engine has been shown. However, the present invention is not limited to this, and other engines such as a diesel engine are used. It is also applicable to control of a belt type continuously variable transmission of a vehicle equipped with In addition to the engine (internal combustion engine), the vehicle power source may be an electric motor or a hybrid power source including both the engine and the electric motor.

  The present invention is not limited to FF (front engine / front drive) type vehicles, but can also be applied to FR (front engine / rear drive) type vehicles and four-wheel drive vehicles.

It is a schematic block diagram which shows an example of the vehicle carrying the belt type continuously variable transmission to which this invention is applied. It is a circuit block diagram of the hydraulic control circuit which controls the hydraulic actuator of the primary pulley of a belt-type continuously variable transmission among hydraulic control circuits. It is a circuit block diagram of the hydraulic control circuit which controls the clamping pressure of the belt of a belt-type continuously variable transmission among hydraulic control circuits. It is a block diagram which shows the structure of control systems, such as ECU. It is a figure which shows an example of the map used for the shift control of a belt-type continuously variable transmission. It is a figure which shows an example of the map used for the belt clamping pressure control of a belt-type continuously variable transmission. It is a flowchart which shows an example of the control routine of a linear solenoid failure determination process. It is a figure which shows the torque capacity at the time of linear solenoid ON failure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Forward / reverse switching device 4 Belt type continuously variable transmission 41 Primary pulley 413 Hydraulic actuator 42 Secondary pulley 423 Hydraulic actuator 101 Engine rotation speed sensor 105 Primary pulley rotation speed sensor 106 Secondary pulley rotation speed sensor 20 Hydraulic control circuit 7 Oil pump 201 Linear solenoid (SLT)
202 Linear solenoid (SLS)
203 Primary regulator valve 301 Upshift transmission control valve 302 Downshift transmission control valve 303 Belt clamping pressure control valve 8 ECU

Claims (3)

A belt having a primary pulley and a secondary pulley, a belt wound around the primary pulley and the secondary pulley, a hydraulic actuator for changing the groove width of the primary pulley, and a hydraulic actuator for changing the groove width of the secondary pulley A control device that is applied to a continuously variable transmission, and includes a belt pressure control linear solenoid and a belt-type pressure control linear solenoid that controls a line pressure supplied to the hydraulic actuator of the secondary pulley. In the control device for the step transmission,
Belt slip determining means for determining the presence or absence of belt slip of the belt type continuously variable transmission, input torque calculating means for calculating input torque to the primary pulley, and belt slip when the input torque is less than a determination value. If there is, it is determined that the belt clamping pressure control linear solenoid is out of order, and if there is belt slip when the input torque is equal to or greater than the determination value, the line pressure control linear solenoid is out of order. A control device for a belt-type continuously variable transmission. The control device for a belt type continuously variable transmission according to claim 1,
The belt slip determining means calculates a gear ratio between the primary pulley and the secondary pulley and determines the presence or absence of belt slip based on the calculated gear ratio. apparatus. The control device for a belt type continuously variable transmission according to claim 1 or 2,
The determination value set for the input torque is a value that is larger than the transmission torque capacity when the belt clamping pressure control linear solenoid fails and smaller than the transmission torque capacity when the line pressure control linear solenoid fails. A control device for a belt-type continuously variable transmission.

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