JP4553549B2 - Control device for belt type continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a belt type continuously variable transmission.
[0002]
[Prior art]
Conventionally, in a belt-type continuously variable transmission, a target gear ratio (target pulley ratio) is set from the vehicle speed and throttle opening, and the groove width of the primary pulley is variably controlled via the gearshift control valve so as to achieve this target gear ratio. By doing so, stepless shifting is performed. In recent years, improvement of fuel efficiency has been particularly desired from the viewpoint of protecting the global environment, and one of them is to set the pulley clamp pressure of the above-described belt-type continuously variable transmission to an optimum value according to the input torque. Patent Document 1 is known as a technique for improving fuel efficiency by reducing the oil pump load of the engine and reducing friction loss. Specifically, when the input torque is small, the line pressure supplied to the speed change control valve and the secondary pulley is controlled to be lower by the pressure regulating valve, thereby reducing the engine load and friction loss while ensuring the belt clamping pressure. I am trying.
[Patent Document 1]
JP 11-336578 A (see page 5, paragraph number 0036)
[0003]
[Problems to be solved by the invention]
However, if the pressure regulating valve fails and the fail operation that always outputs the maximum pressure due to the fail control is activated, the engine speed will increase due to the increased oil pump load, and the pulley clamp pressure will always increase. There is a risk that friction loss may occur due to the setting, and fuel consumption deteriorates.
[0004]
The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to detect the failure of the pressure regulating valve that regulates the line pressure, in particular, whether fuel pressure can be reliably regulated to a low pressure, thereby improving the fuel efficiency. It is an object of the present invention to provide a control device for a belt type continuously variable transmission that prevents deterioration.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, there is provided a pressure regulating valve for regulating the hydraulic pressure supplied from a hydraulic pressure source, and a pressure regulating valve for controlling the pressure regulating state of the pressure regulating valve in accordance with the running state of the vehicle. Control means, a primary pulley and a secondary pulley that sandwich the V-belt, and a hydraulic pressure supplied from the pressure regulating valve to supply the primary pulley or the secondary pulley, and change a groove width of the pulley to change a gear ratio. Variable speed change control valve and hydraulic pressure of the secondary pulleyDetected valueSecondary pulley oil pressure detecting means for detecting the pressure, a pressure reducing valve for reducing the oil pressure of the secondary pulley based on a control signal, the speed change control valve so as to achieve a target speed ratio set based on the vehicle speed and the throttle opening, In a control device for a belt-type continuously variable transmission provided with a speed ratio control means for controlling the pressure reducing valve, a pressure regulating valve failure judging means for judging a failure of the pressure regulating valve is provided, and the pressure regulating valve failure judging means comprises: The hydraulic pressure detected by the secondary pulley hydraulic pressure detection means is output to the gear ratio control means to output a command to minimize the pressure reduction amount of the pressure reducing valve and to the pressure regulating valve control means to adjust the pressure to the lowest pressure.From detected valueMinimum pressureSubtracting the command value for pressure adjustmentWhen the pressure is greater than or equal to a predetermined value, the pressure regulating valve is determined to be a failure stuck to the maximum output side.
[0006]
  According to a second aspect of the present invention, in the control device for the belt-type continuously variable transmission according to the first aspect, the pressure regulation valve failure determination is permitted.OrProviding a failure determination permission means for prohibiting the failure determination permission means, even if the vehicle is in a stationary state and the hydraulic pressure can be generated reliably and the hydraulic pressure control different from the normal hydraulic pressure control is executed. A feature is that the failure judgment is permitted only when it does not contribute to transmission.
[0007]
According to a third aspect of the present invention, in the control device for the belt type continuously variable transmission according to the first or second aspect, the range position detecting means for detecting the range position of the select lever selected by the driver, and the vehicle speed are detected. Vehicle speed detecting means, accelerator pedal opening detecting means, engine speed detecting means for detecting engine speed, and oil temperature detecting means for detecting oil temperature in the transmission, the failure determination permission means, The detected range position is the neutral range or parking range, the detected vehicle speed is a value that can be determined as vehicle stop, the accelerator pedal is not depressed, and the engine speed is the number of revolutions that can generate hydraulic pressure As described above, when the oil temperature is within an area where controllability can be ensured, failure determination is permitted.
[0008]
  According to a fourth aspect of the present invention, the pressure regulating valve for regulating the hydraulic pressure supplied from the hydraulic power source, the pressure regulating valve control means for controlling the pressure regulating state of the pressure regulating valve according to the running state of the vehicle, and the V belt are sandwiched. A primary pulley and a secondary pulley that perform a stroke drive based on a shift command, a first port connected to a hydraulic oil supply passage that supplies a hydraulic pressure regulated by the pressure regulating valve, and a cylinder chamber of the primary pulley A second port connected to the hydraulic pressure supply and discharge oil passage communicating with the third port, a third port connected to the discharge oil passage discharging the oil in the cylinder chamber of the primary pulley, and a blocking position for blocking communication of each port, When the speed increasing actuator is driven on the speed increasing side stroke, it moves to the speed increasing position where the first port and the second port communicate with each other. In this case, a shift control valve that controls a hydraulic pressure supplied to the cylinder chamber of the primary pulley, and a groove width of the primary pulley is configured by a spool that moves to a deceleration position that communicates the second port and the third port. A mechanical feedback mechanism for detecting and returning the spool driven by the speed change actuator to the shut-off position, a primary pulley hydraulic pressure detecting means for detecting a hydraulic pressure detection value of the primary pulley, and a setting based on the vehicle speed and the throttle opening In a control device for a belt-type continuously variable transmission, comprising: a transmission ratio control unit that controls the transmission actuator so as to achieve a target transmission ratio; and a transmission ratio detection unit that detects the transmission ratio; A pressure regulating valve failure judging means for judging a failure, and the pressure regulating valve failure judging means when a predetermined condition is satisfied. Failure determination permission means for permitting the means to determine failure of the pressure regulating valve, and the pressure regulating valve failure determination means is configured to control the speed ratio control when the detected speed ratio is on the maximum speed increasing ratio side. A command for driving the speed change actuator in a direction to communicate the first port and the second port is output to the first port, and when the failure determination permission means permits the failure determination, the speed change actuator is moved to the first port. To the overstroke position beyond the speed increasing position where the second port communicates with the second port.The hydraulic pressure regulated by the pressure regulating valve is directly supplied to the cylinder chamber of the primary pulley.When the value obtained by subtracting the command value of the pressure regulating valve control means from the hydraulic pressure detected by the primary pulley hydraulic pressure sensing means is equal to or greater than a predetermined value, it is determined that the pressure regulating valve is stuck on the maximum output side. Characterized by means.
[0009]
  According to a fifth aspect of the present invention, in the control device for the belt type continuously variable transmission according to the fourth aspect,NoteThe failure determination permission means permits failure determination when the speed ratio is on the maximum speed ratio side and the target speed ratio is on the maximum speed ratio side.
[0010]
  According to a sixth aspect of the invention, in the control device for the belt type continuously variable transmission according to the fourth or fifth aspect, the engine speed detecting means for detecting the engine speed is provided, and the failure determination is performed.PermissionThe means is characterized by permitting a failure determination when the engine speed is equal to or higher than a speed capable of generating hydraulic pressure.
[0011]
[Action and effect of the invention]
  In the control device for the belt type continuously variable transmission according to claim 1, the pressure regulating valve failure judging means outputs a command for minimizing the pressure reducing amount of the pressure reducing valve to the speed ratio control means, so that the line is connected to the secondary pulley. The pressure is supplied as it is. At this time, a command for regulating the pressure to the lowest possible pressure is output to the pressure regulating valve control means, and the hydraulic pressure detected by the secondary pulley hydraulic pressure sensing meansFrom detected valueLine pressureTheMinimum pressureSubtracting the command value for pressure adjustmentIs equal to or greater than a predetermined value, it is determined that the pressure regulating valve is stuck to the maximum output side because a high line pressure is output even though the minimum pressure command is output. Thereby, even if it is the structure which is not provided with the line pressure detection means which detects a line pressure directly, the failure which the pressure regulation valve stuck to the maximum output side can be detected.
[0012]
In the control device for the belt-type continuously variable transmission according to claim 2, the failure determination permitting means includes a hydraulic control that is capable of reliably generating a hydraulic pressure when the vehicle is in a stopped state and is different from a normal hydraulic control. Even if executed, the failure judgment is permitted only when it does not contribute to power transmission. That is, a failure is detected by intentionally performing hydraulic control different from normal. Therefore, the failure can be detected in a state where the safety of the vehicle is ensured.
[0013]
In the control device for the belt-type continuously variable transmission according to claim 3, when the detected range position is the neutral range or the parking range and the detected vehicle speed is 0, the vehicle is considered to be in a stopped state. Further, if the accelerator pedal is not depressed, the driver does not intend to start. In addition, when the engine speed is equal to or higher than the speed at which oil pressure can be generated and the oil temperature is within an area where controllability can be ensured, it is considered that an environment for accurately judging the failure is in place. A failure can be detected.
[0014]
  According to a fourth aspect of the present invention, the pressure regulating valve failure judging means drives the speed change actuator to stroke in the direction in which the first port and the second port are communicated with the speed ratio control means during traveling on the maximum speed ratio side. When the failure determination permission means permits failure determination, the shift actuator isExceeded the speed increasing position where the 1st port and 2nd port communicateDrive to the overstroke position, primary pulley(Primary pulley cylinder chamber)To line pressure(Hydraulic pressure regulated by pressure regulating valve)Is in a state of being supplied as it is. Even during traveling, the groove width of the primary pulley is the narrowest on the maximum speed ratio side, and even if the speed change actuator is further driven to move the spool to the line pressure supply side, the speed ratio will be changed. There is no.
  In this state, when the value obtained by subtracting the command value of the pressure regulating valve control means from the oil pressure detection value detected by the primary pulley oil pressure detection means is equal to or greater than a predetermined value, the line pressure is output higher than the command value. Judgment is that the pressure valve is stuck on the maximum output side. Thereby, even if it is the structure which is not provided with the line pressure detection means which detects a line pressure directly, the failure which the pressure regulation valve stuck to the maximum output side can be detected.
[0015]
In the control device for the belt type continuously variable transmission according to claim 5, the failure determination permitting means is configured such that when the speed ratio is on the maximum speed ratio side and the target speed ratio is on the maximum speed ratio side, By permitting the failure determination, the failure determination is permitted only in the steady traveling in which the driver keeps the traveling state constant. Therefore, from the state in which the speed change actuator is driven to the speed increase ratio side from the normal state by the failure determination means, the responsiveness is not deteriorated by driving to the speed reduction ratio side, for example, based on the driver's speed change request. Faults can be detected without affecting the state.
[0016]
In the control device for the belt type continuously variable transmission according to claim 6, if the engine speed is equal to or higher than the speed capable of generating the hydraulic pressure, the hydraulic pressure necessary for determining the failure is secured, and the malfunction is surely prevented. Can be detected.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
(Embodiment)
First, the configuration will be described.
FIG. 1 is a schematic configuration diagram of a V-belt type continuously variable transmission, and FIG. 2 is a conceptual diagram of a hydraulic control unit and a CVT control unit.
[0019]
In FIG. 1, a continuously variable transmission 5 is connected to an engine 1 via a torque converter 2 having a lock-up clutch and a forward / reverse switching mechanism 4, and a primary pulley 10 on the input shaft side and an output shaft 13 as a pair of variable pulleys. The secondary pulley 11 connected to is provided. The pair of variable pulleys 10 and 11 are connected by a V belt 12. The output shaft 13 is connected to the differential 6 via an idler gear 14 and an idler shaft.
[0020]
The transmission ratio of the continuously variable transmission 5 and the contact friction force of the V belt are controlled by a hydraulic control unit (hydraulic CU) 100 that responds to a command from the CVT control unit (CVTCU) 20. The CVTCU 20 determines and controls a gear ratio and a contact friction force based on input torque information from an engine control unit (ECU) 21 that controls the engine 1 and an output from a sensor or the like described later.
[0021]
The primary pulley 10 of the continuously variable transmission 5 includes a fixed conical plate 10b that rotates integrally with an input shaft, a V-shaped pulley groove that is disposed opposite to the fixed conical plate 10b, and a primary pulley cylinder. The movable conical plate 10a can be displaced in the axial direction by hydraulic pressure (primary pressure) acting on the chamber 10c.
[0022]
On the other hand, the secondary pulley 11 is disposed to be opposed to the fixed conical plate 11b that rotates integrally with the output shaft 13 and to form a V-shaped pulley groove, and to the secondary pulley cylinder chamber 11c. The movable conical plate 11a can be displaced in the axial direction in accordance with the acting hydraulic pressure (secondary pressure).
[0023]
Here, the primary pulley cylinder chamber 10c and the secondary pulley cylinder chamber 11c are set to an equal pressure receiving area.
[0024]
The drive torque input from the engine 1 is input to the continuously variable transmission 5 via the torque converter 2 and the forward / reverse switching mechanism 4, and is transmitted from the primary pulley 10 to the secondary pulley 11 via the V belt 12. At this time, the movable conical plate 10a of the primary pulley 10 and the movable conical plate 11a of the secondary pulley 11 are displaced in the axial direction, and the contact radius with the V belt 12 is changed to change the gear ratio between the primary pulley 10 and the secondary pulley 11. Can be changed continuously.
[0025]
The transmission ratio of the continuously variable transmission 5 and the contact friction force of the V belt 12 are controlled by a hydraulic pressure CU100.
[0026]
As shown in FIG. 2, the hydraulic pressure CU 100 is configured so that the line pressure P discharged from the oil pump 22_LA pressure regulator valve 60 for controlling the pressure (corresponding to the pressure regulating valve described in the claims), a shift control valve 30 for controlling the hydraulic pressure (hereinafter referred to as primary pressure) of the primary pulley cylinder chamber 10c, and supply to the secondary pulley cylinder chamber 11c The pressure reducing valve 61 for controlling the pressure (hereinafter referred to as secondary pressure) is mainly configured.
[0027]
The shift control valve 30 is connected to a servo link 50 constituting a mechanical feedback mechanism, is driven by a step motor 40 connected to one end of the servo link 50, and is connected to the other end of the servo link 50. The groove width, that is, feedback of the actual gear ratio is received from the movable conical plate 10a.
[0028]
The line pressure control is composed of a pressure regulator valve 60 having a solenoid that regulates the hydraulic pressure from the oil pump 22, and based on a command (for example, a duty signal) from the CVTCU 20, a predetermined line pressure P corresponding to the operation state_L(Corresponding to the pressure regulating valve control means described in the claims).
[0029]
Line pressure P_LAre respectively supplied to a speed change control valve 30 for controlling the primary pressure and a pressure reducing valve 61 having a solenoid for controlling the secondary pressure.
[0030]
The gear ratio between the primary pulley 10 and the secondary pulley 11 is controlled by a step motor 40 (corresponding to the shift actuator described in the claims) driven in response to a shift command signal from the CVTCU 20, and a servo link that responds to the step motor 40. The spool 31 of the speed change control valve 30 is driven according to the displacement of 50, and the line pressure P supplied to the speed change control valve 30 is_LIs adjusted to supply the primary pressure to the primary pulley 10, and the groove width is variably controlled and set to a predetermined gear ratio (corresponding to the mechanical feedback mechanism described in the claims).
[0031]
Note that the shift control valve 30 adjusts the primary pressure so as to achieve the target gear ratio commanded at the drive position of the step motor 40 by performing the suction and discharge of the hydraulic pressure to the primary pulley cylinder chamber 10c by the displacement of the spool 31. When shifting is actually completed, the spool 31 is closed in response to the displacement from the servo link 50.
[0032]
In FIG. 1, the CVTCU 20 includes a primary pulley speed sensor 26 that detects the rotational speed of the primary pulley 10 of the continuously variable transmission 5, a secondary pulley speed sensor 27 that detects the rotational speed of the secondary pulley 11, and the secondary pulley 11. A signal from a hydraulic pressure sensor 28 (corresponding to the secondary pulley hydraulic pressure detecting means described in the claims) that detects the secondary pressure applied to the cylinder chamber 11c, and an inhibitor switch 23 (corresponding to the range position detecting means described in the claims). Select position, stroke (or accelerator pedal opening) from the operation amount sensor 24 (corresponding to the accelerator pedal opening detecting means described in claims) corresponding to the operation amount of the accelerator pedal operated by the driver, oil temperature The oil temperature of the continuously variable transmission 5 is detected from a sensor 25 (corresponding to the oil temperature detecting means described in the claims) The contact friction force of the gear ratio or the V-belt 12 crowded viewed variably controlled. In addition, a signal from an engine speed sensor 29 (corresponding to the engine speed detecting means described in the claims) is input to the CVTCU 20 via the ECU 21.
[0033]
The CVTCU 20 determines the target gear ratio according to the vehicle speed and the accelerator pedal stroke, drives the step motor 40 to control the actual gear ratio toward the target gear ratio, the input torque and the gear ratio, A pulley pressure (hydraulic pressure) control unit 202 that controls the thrust (contact frictional force) of the primary pulley 10 and the secondary pulley 11 according to the oil temperature, speed change speed, and the like.
[0034]
The pulley pressure control unit 202 calculates the line pressure P from the input torque information, the gear ratio based on the primary pulley rotation speed and the secondary pulley rotation speed, and the oil temperature._LThe target pressure value is determined, and the line pressure P is determined by driving the solenoid of the pressure regulator valve 60._LTo control. Further, the target value of the secondary pressure is determined, the solenoid of the pressure reducing valve 61 is driven according to the detected value and the target value of the hydraulic sensor 28, and the secondary pressure is controlled by feedback control (closed loop control).
[0035]
Next, the structure of the forward / reverse switching mechanism 4 will be described.
A hydraulic circuit that controls the engagement and release of the forward clutch 8 and the reverse brake 9 of the forward / reverse switching mechanism 4 by ON / OFF of the engagement pressure is represented by the line pressure P_LThis is shown in FIG.
[0036]
Line pressure P by pressure regulator valve 60_LThe surplus oil surplus during the control is sent from the pressure regulator valve 60 to the circuit 71, and the clutch regulator valve 70 uses the surplus oil as a medium to convert the surplus oil in the circuit 71 to a predetermined clutch original pressure P._coAdjust pressure.
[0037]
The pressure regulator valve 60 and the clutch regulator valve 70 have a control pressure P generated by the 2-way linear solenoid 80 according to the duty D based on a constant pilot pressure from a pilot valve (not shown)._sThat is, in response to the 2-way linear solenoid drive duty D, the line pressure P_LAnd clutch original pressure P_coControl pressure P_sThat is, the control is performed based on, for example, the map shown in FIG.
[0038]
By the way, line pressure P_LIs the minimum value P according to the 2-way linear solenoid drive duty D_LMINAnd maximum value P_LMAXAnd the clutch original pressure P_COIs the minimum value P according to the 2-way linear solenoid drive duty D_CMINAnd maximum value P_CMAXAs shown in FIG.
[0039]
Clutch original pressure P_COIs supplied to the select switching valve 90. This select switching valve 90 has a clutch original pressure P in the forward range._COIs supplied to the forward clutch 8 and its engagement pressure P_cAnd the engagement pressure P of the reverse brake 9_bDrain. In the reverse range, the clutch original pressure P_coIs supplied to the reverse brake 9 and its fastening pressure P_bAnd the engagement pressure P of the forward clutch 8_cDrain. Furthermore, in the parking / stopping range, the clutch pressure P_coIn the state where the engine is cut off, the engagement pressure P of the forward clutch 8_cAnd the engagement pressure P of the reverse brake 9_bDrain together.
[0040]
Accumulators 81 and 91 are connected to the engagement pressure circuit of the forward clutch 8 and the engagement pressure circuit of the reverse brake 9, respectively. These accumulators 81 and 91 are provided with accumulator pistons 81a and 91a, and actuate accumulator springs 81b and 91b in one direction, and a clutch base pressure P in a direction opposite to the accumulator springs 81b and 91b._coActs as an accumulator back pressure.
[0041]
Therefore, the accumulators 81 and 91 are the clutch source pressure P that acts as the accumulator back pressure._coIn accordance with the engagement pressure P of the corresponding forward clutch 8_cAnd the engagement pressure P of the reverse brake 9_bCan be transiently controlled.
[0042]
Next, the operation will be described.
[Normal shift control processing]
The normal shift control by the CVTCU 20 will be described with reference to the flowchart of FIG.
[0043]
First, in step S1, the actual gear ratio is calculated from the ratio between the primary pulley rotational speed detected by the primary pulley speed sensor 26 and the secondary pulley rotational speed detected by the secondary pulley speed sensor 27.
[0044]
In step S2, the input torque to the continuously variable transmission 5 is calculated from the input torque information from the ECU 21. This input torque information includes, for example, the fuel injection amount (injection pulse width) of the engine 1 and the engine speed.
[0045]
Next, in step S3, the required secondary pressure (required secondary pressure) is calculated with reference to the map of FIG. 6 based on the actual gear ratio and the input torque.
In this map, the lower the gear ratio (Od side), the lower the hydraulic pressure, the higher the gear ratio (Lo side), the higher the hydraulic pressure, and the higher the input torque, the higher the hydraulic pressure and the lower the input torque. The hydraulic pressure is set low and is set in advance.
[0046]
In step S4, the required primary pressure (required primary pressure) is calculated based on the actual gear ratio and the input torque with reference to the map of FIG.
In this map, the lower the gear ratio, the lower the hydraulic pressure, the higher the hydraulic pressure, the higher the hydraulic pressure, and the higher the input torque, the higher the hydraulic pressure, and the lower the hydraulic pressure, the lower the hydraulic pressure. Thus, it is set to be relatively high on the small side of the gear ratio and relatively low on the large side of the gear ratio. However, depending on the input torque, the magnitude relationship between the required primary pressure and the required secondary pressure may be reversed.
[0047]
Next, in step S5, a primary pressure operation amount that is a target value of the primary pressure is calculated by the following equation.
Primary pressure operation amount = Required primary pressure + Offset amount
Here, the offset amount is a value (added value of hydraulic pressure) set in accordance with the characteristics of the shift control valve 30, and the pressure loss characteristic is not completely proportional to the hydraulic pressure, so this is compensated for. Value.
[0048]
In step S6, the magnitude relation between the primary pressure operation amount and the necessary secondary pressure obtained in step S3 is compared and determined. If the primary pressure operation amount is larger, the process proceeds to step S7, and if the required secondary pressure is greater than or equal to the primary pressure operation amount, the process proceeds to step S8.
[0049]
In step S7, the line pressure P_LThis control is terminated with the line pressure manipulated variable, which is the target value, as the primary pressure manipulated variable.
[0050]
In step S8, the control is terminated with the line pressure manipulated variable as the required secondary pressure.
[0051]
As described above, after the larger one of the primary pressure operation amount and the necessary secondary pressure is obtained as the line pressure operation amount (target oil pressure), the control amount (duty signal or the like) for driving the solenoid of the pressure regulator valve 60 is obtained. The pressure regulator valve 60 is driven after conversion.
[0052]
(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the case where the pressure regulator valve 60 that regulates the line pressure is fixed to the maximum output side (hereinafter referred to as the MAX side) is detected. The necessity to detect this MAX side sticking is described.
In the configuration of the above-described embodiment, the hydraulic pressure supplied to the primary pulley cylinder chamber 10 c is supplied via the shift control valve 31. On the other hand, the secondary pulley cylinder chamber 11 c is supplied via a pressure reducing valve 61. Therefore, even if the pressure regulator valve 60 is fixed to the MAX side, the shift control itself can be achieved. However, when the line pressure is always high, the belt clamping pressure or the like becomes too high, and the frictional force during torque transmission may cause a deterioration in fuel consumption.
[0053]
[Line pressure failure judgment control when the vehicle is stopped]
FIG. 8 is a flowchart showing the control content of the line pressure failure determination control.
[0054]
In step 101, a range signal, a vehicle speed, an accelerator pedal stroke, an engine speed, an oil temperature, a failure flag of each solenoid and sensors are read.
[0055]
  In step 102, it is determined whether or not a failure determination permission condition is satisfied. If satisfied, the process proceeds to step 103, and otherwise the control is terminated (corresponding to the failure determination permission means described in the claims). Here, the failure determination permission conditions are shown below.
・ Range signal is N or P range (power is not transmitted)
・ Vehicle speed = 0 (vehicle stopped)
・ Idle state where accelerator is not stepped on (state where driver does not intend to start)
・ The engine speed exceeds the speed that can output the line pressure.
・ Oil temperature is within the specified oil temperature range (because viscosity is high and controllability may be reduced at low temperatures, and oil balance may be insufficient at high temperatures)
-State that each solenoid, oil pressure sensor 28 and each rotation sensor (26, 27, 29) has not failed
  Only when all the above conditions are satisfied, it is determined that a safe state has been secured even if the hydraulic control is controlled to be different from the normal state, and the failure determination is permitted.The
[0056]
In step 103, the MIN command value that minimizes the command value of the line pressure is output.
[0057]
In step 104, the MAX command value is output to the pressure reducing valve 61 that controls the secondary hydraulic pressure.
[0058]
In step 105, the first timer is counted up.
[0059]
In step 106, the timer count value is a predetermined value τ.₀If it is greater than the predetermined time τ₀If the time has passed, the process proceeds to step 107, and otherwise the first timer count is continued.
[0060]
In step 107, it is determined whether or not the absolute value of the difference between the line pressure command value and the detected value of the hydraulic pressure sensor 28 is larger than a predetermined value A. If so, the process proceeds to step 108, and otherwise the control is terminated.
[0061]
In step 108, the second timer is counted up.
[0062]
In step 109, the second timer count value is a predetermined value τ.₁If it is larger, the process proceeds to Step 110. Otherwise, Steps 107 to 109 are repeated.
[0063]
  In step 110, it is determined that the pressure regulator valve 60 for controlling the line pressure is a MAX fixing failure.TheSteps 103 to 110 correspond to failure determination permission means described in claims.
[0064]
The contents of the control will be described based on the time chart of FIG.
If the failure determination permission condition is satisfied at time t1, a line pressure MIN control command is output in step 103, and the supply hydraulic pressure to the secondary cylinder chamber 11c is output in step 104 so that the line pressure is supplied as it is. The drain amount is 0, that is, the MAX command is output. In the belt type continuously variable transmission of the present embodiment, only the hydraulic pressure supplied to the secondary pulley cylinder chamber 11c is detected as a hydraulic pressure sensor, and no hydraulic pressure sensor for detecting the line pressure itself is provided. Therefore, by setting the drain amount of the pressure reducing valve 61 to 0, the line pressure can be detected by the hydraulic sensor 28 that detects the hydraulic pressure of the secondary pulley cylinder chamber 11c.
[0065]
A predetermined time τ when the failure determination permission condition is satisfied and the hydraulic pressure detected by the hydraulic sensor 28 is stabilized.₁During this period, that is, until the time t2, the hydraulic pressure is not detected. And the predetermined time τ₁After the lapse of time, the oil pressure of the oil pressure sensor 28 is detected from time t2, and the deviation between the detected oil pressure and the MIN pressure that is the line pressure command value is detected. A state where this deviation is equal to or greater than a predetermined amount A is a predetermined time τ₂When continuously detected, at time t3, a high line pressure is supplied despite the fact that the MIN pressure is commanded as the line pressure command value, and the pressure regulator valve 60 is fixed to MAX. Failure is determined.
[0066]
As described above, even if the configuration does not include the hydraulic sensor that directly detects the line pressure, but includes only the hydraulic sensor that detects the hydraulic pressure of the secondary pulley cylinder chamber 11c, it detects the MAX side adhesion of the line pressure. This makes it possible to prevent deterioration in fuel consumption due to an increase in line pressure.
[0067]
(Second embodiment)
FIG. 10 is a conceptual diagram of a hydraulic control unit and a CVT control unit in the second embodiment. In the first embodiment, only the hydraulic sensor 28 for detecting the hydraulic pressure of the secondary cylinder chamber 11c is provided. However, in the second embodiment, in addition to the hydraulic sensor 28, the primary pressure for detecting the hydraulic pressure of the primary cylinder chamber 10c is used. The difference is that a hydraulic sensor 32 (corresponding to the primary pulley hydraulic pressure detecting means described in the claims) is provided. Since the rest is basically the same as that of the first embodiment, the description thereof is omitted.
[0068]
In the second embodiment, as in the first embodiment, the case where the pressure regulator valve 60 that regulates the line pressure is fixed to the maximum output side (hereinafter referred to as the MAX side) is detected. While the detection control is performed when the vehicle is stopped, the second embodiment is different in that the detection control is performed during traveling.
[0069]
[Line pressure failure judgment control during vehicle travel]
FIG. 11 is a flowchart showing the control content of the line pressure failure determination control.
[0070]
In step 201, the actual gear ratio, the target gear ratio, the engine speed, the secondary cylinder chamber hydraulic pressure, each solenoid, and the sensor failure flags are read.
[0071]
  In step 202, it is determined whether or not a failure determination permission condition is satisfied. If satisfied, the process proceeds to step 203, and otherwise the control is terminated. Here, the failure determination permission conditions are shown below.
・ Actual gear ratio <predetermined gear ratio (equivalent to overdrive)
When the actual transmission ratio is equivalent to overdrive, as shown in the transmission ratio-primary pressure map of FIG. 7, the required primary pressure is low, and therefore the line pressure is also controlled to a low value.The
・ Target speed ratio <predetermined speed ratio (equivalent to overdrive)
This is because when the target gear ratio is equivalent to overdrive, it can be determined that the speed change state is a steady state since it corresponds to overdrive at the present time (corresponding to claim 5).・ No shift judgment
If the vehicle is not traveling constantly at a high gear ratio without crossing the gear line in the gear map, the gear ratio must be changed according to the driver's intention, and the response by overstroke driving the step motor This is to prevent delay.
・ Engine speed> Predetermined value
If the engine speed is greater than or equal to the predetermined value, sufficient oil pressure is ensured on the oil balance.The
・ Secondary hydraulic pressure <predetermined value
The belt-type continuously variable transmission shifts with the balance of the belt clamping force of the primary pulley and the secondary pulley, and if a low line pressure is supplied as it is to the primary pulley while the secondary hydraulic pressure is high, there is a risk of shifting. It is.
-Each solenoid, hydraulic sensor 28, each rotation sensor (26, 27, 29) and step motor are not failed
Only when all of the above conditions are satisfied, it is determined that a safe state has been secured even if the hydraulic control is controlled to be different from the normal state, and failure determination is permitted (to the failure determination permission means described in the claims) Equivalent).
[0072]
In step 203, the step motor is driven to the overstroke position.
[0073]
In step 204, the first timer is counted up.
[0074]
In step 205, the timer count value is a predetermined value τ.₀If it is greater than the predetermined time τ₀If the time has passed, the process proceeds to step 206, and otherwise the count of the first timer is continued.
[0075]
In step 206, it is determined whether or not the absolute value of the difference between the line pressure command value and the detected value of the primary hydraulic sensor 32 is larger than a predetermined value A. If larger, the process proceeds to step 207, otherwise the control is terminated. .
[0076]
In step 207, the second timer is counted up.
[0077]
In step 208, the second timer count value is a predetermined value τ.₁If it is larger, the process proceeds to Step 209. Otherwise, Steps 206 to 208 are repeated.
[0078]
In step 209, it is determined that the pressure regulator valve 60 that controls the line pressure is in the MAX fixing failure. Steps 203 to 209 correspond to failure determination permission means described in the claims.
[0079]
  The contents of the control will be described based on the time chart of FIG.
When the failure determination permission condition is satisfied at time t1, the step motor is driven to the overstroke position in step 203.The
[0080]
Here, the reason why the step motor is driven to the overstroke position will be described. FIG. 13 is a schematic diagram of a mechanical feedback mechanism for shift control. When shifting the gear ratio to the Hi side, the groove width of the primary pulley is reduced. Accordingly, the hydraulic pressure is supplied to the primary pulley cylinder chamber 10c. First, the step motor 40 is moved to the right in the figure. As a result, the spool 31a moves to the right, and the hydraulic pressure is supplied by communicating the line pressure port. The movable conical plate of the primary pulley moves to the left in the figure and shifts to the Hi side. Due to the movement of the movable conical plate, the spool 31a moves to the left in the figure, and again shuts off the line pressure port. Accordingly, the supply of hydraulic pressure is stopped and the shift is completed.
[0081]
The state in which the failure detection in the second embodiment is permitted is steady running in a high gear ratio (overdrive) state. At this time, the groove width of the primary pulley is the narrowest, and even if hydraulic pressure is supplied, the gear ratio does not change. Therefore, the step motor 40 is driven to the overstroke position, the line pressure is directly supplied to the primary pulley cylinder chamber 10c in a high gear ratio state, and the primary hydraulic sensor 32 can detect the line pressure.
[0082]
A predetermined time τ when the failure determination permission condition is satisfied and the detected hydraulic pressure of the primary hydraulic sensor 32 is stabilized.₁During this period, that is, until the time t2, the hydraulic pressure is not detected. And the predetermined time τ₁After the lapse of time, the oil pressure of the primary oil pressure sensor 32 is detected from time t2, and a deviation between the detected oil pressure and the line pressure command value is detected. A state where this deviation is equal to or greater than a predetermined amount A is a predetermined time τ₂When continuously detected, the line pressure higher than the line pressure command value is supplied at time t3, and it is determined that the pressure regulator valve 60 is stuck to MAX.
[0083]
As described above, the primary pressure sensor 32 that detects the hydraulic pressure in the primary pulley cylinder chamber 10c does not include a hydraulic pressure sensor that directly detects the line pressure, and the MAX side sticking of the line pressure can be detected during traveling. This makes it possible to prevent deterioration in fuel consumption due to an increase in line pressure.
[0084]
The embodiment of the present invention, the first example, and the second example have been described above, but the specific configuration of the present invention is not limited to the present embodiment and does not depart from the gist of the invention. Any change in the design of the range is included in the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a V-belt type continuously variable transmission according to a first embodiment.
FIG. 2 is a conceptual diagram of a hydraulic control unit and a CVT control unit in the first embodiment.
FIG. 3 is a diagram showing a hydraulic circuit that engages and releases a forward clutch and a reverse brake by ON / OFF of a fastening pressure together with a line pressure control circuit in the first embodiment.
FIG. 4 is a diagram showing a relationship between solenoid drive duty, line pressure, and clutch original pressure in the first embodiment.
FIG. 5 is a flowchart showing a flow of hydraulic control performed by a pulley pressure control unit of the CVT control unit in the first embodiment.
FIG. 6 is a map of required secondary pressure according to the gear ratio and input torque in the first embodiment.
FIG. 7 is a map of required primary pressure according to the gear ratio and input torque in the first embodiment.
FIG. 8 is a flowchart showing the control content of line pressure failure determination control in the first embodiment.
FIG. 9 is a time chart showing line pressure failure determination control in the first embodiment.
FIG. 10 is a conceptual diagram of a hydraulic control unit and a CVT control unit in the second embodiment.
FIG. 11 is a flowchart showing the control content of line pressure failure determination control in the second embodiment.
FIG. 12 is a time chart showing line pressure failure determination control in the second embodiment.
FIG. 13 is a schematic diagram showing the position of the shift control valve when the stepping motor in the second embodiment overstrokes.
[Explanation of symbols]
1 engine
2 Torque converter
4 Forward / backward switching mechanism
5 continuously variable transmission
6 Differential gear
8 Forward clutch
9 Reverse brake
10 Primary pulley
10a Movable conical plate
10b Fixed conical plate
10c Primary pulley cylinder chamber
11 Secondary pulley
11a Movable conical plate
11b Fixed conical plate
11c Secondary pulley cylinder chamber
12 V belt
13 Output shaft
14 idler gear
20 CVT control unit (CVTCU)
21 Engine control unit (ECU)
22 Oil pump
23 Inhibitor switch
24 Operation amount sensor
25 Oil temperature sensor
26 Primary pulley speed sensor
27 Secondary pulley speed sensor
28 Hydraulic sensor
29 Engine speed sensor
30 Shift control valve
31 spool
32 Primary hydraulic sensor
40 step motor
50 servo links
60 Pressure regulator valve
61 Pressure reducing valve
70 Clutch regulator valve
71 circuits
80 2-way linear solenoid
81 Accumulator
81a Accum Piston
81b Accumulator spring
90 Select switching valve 90
91 Accumulator
91a Accum Piston
91b Accumulator spring
100 Hydraulic control unit (hydraulic CU)
201 Shift control unit
202 Pulley pressure control unit

Claims (6)

A pressure regulating valve for regulating the hydraulic pressure supplied from the hydraulic source;
Pressure regulating valve control means for controlling the pressure regulating state of the pressure regulating valve according to the running state of the vehicle;
A primary pulley and a secondary pulley that sandwich the V-belt;
A shift control valve that controls the hydraulic pressure supplied from the pressure regulating valve to supply to the primary pulley or the secondary pulley, and changes the gear ratio by changing the groove width of the pulley;
Secondary pulley oil pressure detection means for detecting the oil pressure detection value of the secondary pulley;
A pressure reducing valve for reducing the hydraulic pressure of the secondary pulley based on a control signal;
Transmission ratio control means for controlling the transmission control valve and the pressure reducing valve so as to be a target transmission ratio set based on a vehicle speed and a throttle opening;
In a control device for a belt-type continuously variable transmission comprising:
A pressure regulating valve failure judging means for judging a malfunction of the pressure regulating valve;
The pressure regulating valve failure judging means outputs a command for minimizing the pressure reducing amount of the pressure reducing valve to the gear ratio control means, and outputs a command for regulating the pressure to the minimum pressure to the pressure regulating valve control means, and the secondary pulley When the value obtained by subtracting the command value for adjusting to the minimum pressure from the detected oil pressure detected by the oil pressure detecting means is equal to or greater than a predetermined value, the pressure adjusting valve is determined to be a failure stuck on the maximum output side. A control device for a belt type continuously variable transmission. The control device for a belt-type continuously variable transmission according to claim 1,
Providing a failure determination permission means for permitting or prohibiting the pressure regulating valve failure determination;
The failure determination permission means determines a failure only when the vehicle is stationary, the hydraulic pressure can be reliably generated, and even if a hydraulic control different from the normal hydraulic control is executed, it does not contribute to power transmission. A control device for a belt-type continuously variable transmission, characterized in that it is a means for permitting the transmission. The control device for a belt-type continuously variable transmission according to claim 1 or 2,
Range position detection means for detecting the range position of the select lever selected by the driver;
Vehicle speed detection means for detecting the vehicle speed;
Accelerator pedal opening detection means;
An engine speed detecting means for detecting the engine speed;
Oil temperature detecting means for detecting the oil temperature in the transmission;
With
The failure determination permission means is a state in which the detected range position is a neutral range or a parking range, the detected vehicle speed is a value at which it can be determined that the vehicle is stopped, the accelerator pedal is not depressed, and the engine speed is A control device for a belt-type continuously variable transmission, characterized in that failure determination is permitted when the oil pressure is equal to or higher than the number of revolutions capable of generating hydraulic pressure and the oil temperature is within a region where controllability can be ensured. A pressure regulating valve for regulating the hydraulic pressure supplied from the hydraulic source;
Pressure regulating valve control means for controlling the pressure regulating state of the pressure regulating valve according to the running state of the vehicle;
A primary pulley and a secondary pulley that sandwich the V-belt;
A speed change actuator that strokes based on a speed change command;
A first port connected to a hydraulic supply oil passage for supplying hydraulic pressure regulated by the pressure regulating valve; a second port connected to a hydraulic supply and discharge oil passage communicating with a cylinder chamber of the primary pulley; and the primary pulley From the third port connected to the discharge oil passage for discharging the oil in the cylinder chamber, and the blocking position for blocking the communication of each port, the first port and the second port when the speed change actuator is driven on the acceleration side stroke drive Hydraulic pressure supplied to the cylinder chamber of the primary pulley is configured by a spool that moves to a speed increasing position that communicates with the port and moves to a speed reducing position that communicates the second port and the third port when driving on the deceleration side. A shift control valve for controlling
A mechanical feedback mechanism for detecting a groove width of the primary pulley and returning the spool driven by the speed change actuator to a blocking position;
Primary pulley oil pressure detection means for detecting a pressure detection value of the primary pulley;
Transmission ratio control means for controlling the transmission actuator so as to achieve a target transmission ratio set based on a vehicle speed and a throttle opening;
Gear ratio detecting means for detecting the gear ratio;
In a control device for a belt-type continuously variable transmission comprising:
A pressure regulating valve failure judging means for judging a failure of the pressure regulating valve;
A failure determination permitting means for permitting the pressure regulating valve failure determining means to determine a failure of the pressure regulating valve when a predetermined condition is satisfied;
Provided,
The pressure regulating valve failure determination means strokes the speed change actuator in a direction in which the first port and the second port are communicated with the speed change ratio control means when the detected speed change ratio is on the maximum speed increase ratio side. A command is output, and when the failure determination permission means permits the failure determination, the shift actuator is stroke-driven to an overstroke position exceeding the acceleration position where the first port and the second port communicate with each other. The hydraulic pressure regulated by the pressure regulating valve is directly supplied to the cylinder chamber of the primary pulley, and a value obtained by subtracting the command value of the pressure regulating valve control means from the hydraulic pressure detected by the primary pulley hydraulic pressure detection means is predetermined. A control device for a belt-type continuously variable transmission, characterized in that when the value is equal to or greater than the value, the pressure regulating valve is determined to be a failure stuck on the maximum output side. . The control device for a belt-type continuously variable transmission according to claim 4,
The belt type continuously variable transmission characterized in that the failure determination permission means permits failure determination when the gear ratio is on the maximum speed ratio side and the target speed ratio is on the maximum speed ratio side. Control device. In the control apparatus of the belt type continuously variable transmission according to claim 4 or 5,
An engine speed detecting means for detecting the engine speed is provided;
The control device for a belt-type continuously variable transmission, wherein the failure determination permission means permits failure determination when the engine speed is equal to or higher than a rotation speed capable of generating hydraulic pressure.

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