JP2004124960A - Controller for belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a belt type continuously variable transmission for preventing the worsening of fuel economy by detecting the failure of a regulating valve regulating a line pressure, in particular, detecting whether the line pressure is surely regulated to low pressure or not. <P>SOLUTION: This controller for a belt type continuously variable transmission comprising a secondary pulley hydraulic pressure detecting means for detecting the hydraulic pressure of a secondary pulley, and a decompression valve for reducing the hydraulic pressure of the secondary pulley on the basis of a control signal, further comprises a regulating valve failure determining means for determining whether the regulating valve fails or not, and a failure determination permitting means for permitting/forbidding the determination of the failure of regulating valve. The regulating valve failure determining means outputs the command to make the decompression of the decompression valve 0, to a change gear ratio control means, and outputs the command for regulating the pressure to a regulatable lowest pressure to the regulating valve control means, and determines the failure when the deviation between the hydraulic pressure detected by the secondary pulley hydraulic pressure detecting means and the lowest pressure is more than a predetermined value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD 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 speed ratio (a target pulley ratio) is set based on a vehicle speed and a throttle opening, and the groove width of a primary pulley is variably controlled via a speed change control valve so as to achieve the target speed ratio. By doing so, a stepless speed change is performed. In recent years, it has been particularly desired to improve fuel efficiency from the viewpoint of protecting the global environment. One of them is to set the pulley clamp pressure of the above-described belt-type continuously variable transmission to an optimal value according to the input torque. Patent Literature 1 is known as a technique for improving fuel efficiency by reducing the load on an oil pump of an engine and reducing friction loss. Specifically, when the input torque is small, the line pressure supplied to the shift control valve and the secondary pulley is controlled to be lower by the pressure regulating valve, thereby reducing the engine load and the friction loss while securing the belt clamping pressure. I'm trying.
[Patent Document 1]
JP-A-11-336578 (refer to page 5, paragraph 0036)
[0003]
[Problems to be solved by the invention]
However, if the pressure regulating valve breaks down and a fail operation that always outputs the maximum pressure due to the fail control is activated, an increase in the engine speed due to an increase in the load on the oil pump causes an increase in the pulley clamp pressure. However, there is a possibility that friction loss may occur due to the setting of, and there is a problem that fuel efficiency is deteriorated.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention is to detect a failure of a pressure regulating valve for regulating a line pressure, in particular, by detecting whether or not pressure regulation can be reliably performed at a low pressure. An object of the present invention is 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, a pressure regulating valve that regulates a hydraulic pressure supplied from a hydraulic pressure source, and a pressure regulating valve that controls a pressure regulating state of the pressure regulating valve according to a traveling state of a vehicle. A control means, a primary pulley and a secondary pulley for holding 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. A shift control valve for changing, a secondary pulley oil pressure detecting means for detecting the hydraulic pressure of the secondary pulley, a pressure reducing valve for reducing the hydraulic pressure of the secondary pulley based on a control signal, and a setting based on a vehicle speed and a throttle opening. A speed ratio control means for controlling the speed change control valve and the pressure reducing valve to achieve a target speed ratio. A pressure regulating valve failure determining means for determining a failure of the pressure regulating valve, wherein the pressure regulating valve failure determining means outputs to the speed ratio control means a command for minimizing the pressure reduction amount of the pressure reducing valve; A command to adjust the pressure to the minimum pressure is output to the control means, and when the difference between the hydraulic pressure detected by the secondary pulley oil pressure detection means and the minimum pressure is equal to or more than a predetermined value, the means is determined to be a failure. I do.
[0006]
According to a second aspect of the present invention, in the control device for a belt-type continuously variable transmission according to the first aspect, failure determination permission means for permitting / prohibiting the pressure regulator failure determination is provided, and the failure determination permission means includes: Even when the vehicle is in a stopped state, the hydraulic pressure can be reliably generated, and even if a hydraulic control different from the normal hydraulic control is executed, a means for permitting a failure determination only when the vehicle does not contribute to power transmission is provided. It is characterized by.
[0007]
According to a third aspect of the present invention, in the control device for a belt-type continuously variable transmission according to the first or second aspect, range position detecting means for detecting a range position of a select lever selected by a driver, and detecting a vehicle speed. Vehicle speed detecting means, accelerator pedal opening degree detecting means, engine speed detecting means for detecting engine speed, and oil temperature detecting means for detecting oil temperature in the transmission. The detected range position is a neutral range or a parking range, the detected vehicle speed is a value at which the vehicle can be determined to be stopped, the accelerator pedal is not depressed, and the engine speed is a speed at which hydraulic pressure can be generated. As described above, when the oil temperature is within the range in which the controllability can be ensured, the failure determination is permitted.
[0008]
According to the fourth aspect of the present invention, the pressure regulating valve regulates the hydraulic pressure supplied from the hydraulic pressure source, pressure regulating valve control means for controlling the pressure regulating state of the pressure regulating valve according to the traveling state of the vehicle, and the V belt is sandwiched. A primary pulley and a secondary pulley, a shift actuator driven based on a shift command, a first port connected to a hydraulic supply oil passage for supplying a hydraulic pressure regulated by the pressure regulating valve, and a cylinder chamber of the primary pulley. A second port connected to a hydraulic supply / discharge oil passage communicating therewith; a third port connected to a discharge oil passage discharging the oil in the cylinder chamber of the primary pulley; and a blocking position for blocking communication between the ports. When the speed change actuator is driven on the speed increasing side, the actuator moves to the speed increasing position communicating the first port and the second port. When the speed change actuator is driven on the speed decreasing side, the second port and the third port are moved to the third position. A shift control valve configured to control a hydraulic pressure to be supplied to a cylinder chamber of the primary pulley, and a groove width of the primary pulley to be detected and driven by the shift actuator. A mechanical feedback mechanism for returning the spool to the shut-off position, primary pulley oil pressure detecting means for detecting the oil pressure of the primary pulley, and the shift actuator so as to attain a target gear ratio set based on a vehicle speed and a throttle opening. In a control device for a belt-type continuously variable transmission, comprising a speed ratio control means for controlling and a speed ratio detecting means for detecting a speed ratio, a pressure regulating valve failure determining means for determining a failure of the pressure regulating valve is provided. When the set speed ratio is on the side of the maximum speed increase ratio, the pressure regulating valve failure determining means is Outputting a command to drive the speed change actuator in a direction to connect the first port and the second port, wherein a deviation between a hydraulic pressure detected by the primary pulley hydraulic pressure detecting means and a command value of the pressure regulating valve control means is a predetermined value or more. In the case of (1), a means for judging a failure is provided.
[0009]
According to a fifth aspect of the present invention, in the control device for a belt-type continuously variable transmission according to the fourth aspect, failure determination permission means for permitting / prohibiting the pressure regulator failure determination is provided, and the failure determination permission means comprises: When the gear ratio is the maximum gear ratio and the target gear ratio is the maximum gear ratio, the failure determination is permitted.
[0010]
According to a sixth aspect of the present invention, in the control device for a belt-type continuously variable transmission according to the fourth or fifth aspect, an engine speed detecting unit for detecting an engine speed is provided, and the failure determination unit includes an engine speed detecting unit. When the number is equal to or higher than the number of rotations at which hydraulic pressure can be generated, a failure determination is permitted.
[0011]
Function and effect of the present invention
In the control device for a belt-type continuously variable transmission according to claim 1, the pressure regulating valve failure determining means outputs a command for minimizing the pressure reduction amount of the pressure reducing valve to the speed ratio control means, so that the line is connected to the secondary pulley. Pressure is supplied as it is. At this time, a command to adjust the pressure to the minimum pressure that can be adjusted is output to the pressure adjustment valve control means, and when the deviation between the oil pressure detected by the secondary pulley oil pressure detection means and the minimum pressure of the line pressure is equal to or more than a predetermined value, Despite the output of the minimum pressure command, a failure is determined because a high line pressure is output. Thus, even if the configuration does not include the line pressure detecting means for directly detecting the line pressure, the failure of the pressure regulating valve can be detected.
[0012]
In the control device for a belt-type continuously variable transmission according to the second aspect, the failure determination permitting means is capable of reliably generating the hydraulic pressure when the vehicle is in a stopped state, and that is different from the normal hydraulic control. Even if is executed, a means for permitting a failure determination only when the vehicle does not contribute to power transmission is adopted. That is, a failure is detected by intentionally performing a hydraulic control that is different from a normal hydraulic control. Therefore, a 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 the third aspect, the detected range position is the neutral range or the parking range, and when the detected vehicle speed is 0, the vehicle is considered to be in a stopped state. If the accelerator pedal is not depressed, the driver has no intention to start. If the engine speed is higher than the speed at which hydraulic pressure can be generated and the oil temperature is within the range where controllability can be ensured, it is considered that the environment for accurately determining a failure is in place, and Failure can be detected.
[0014]
In the invention described in claim 4, the pressure regulating valve failure determining means drives the speed change actuator to the speed ratio control means during traveling on the highest speed ratio side, and the line pressure is supplied to the primary pulley as it is. State. Even during traveling, the groove width of the primary pulley is the narrowest at the maximum speed ratio side, and the gear ratio will be changed even if the speed change actuator is further driven to set the spool to the line pressure supply side. There is no.
In this state, when the deviation between the oil pressure detected by the primary pulley oil pressure detecting means and the command value of the pressure regulating valve control means is equal to or more than a predetermined value, the line pressure is output higher than the command value, and it is determined that a failure has occurred. . Thus, even if the configuration does not include the line pressure detecting means for directly detecting the line pressure, the failure of the pressure regulating valve can be detected.
[0015]
In the control device for a belt-type continuously variable transmission according to the fifth aspect, the failure determination permission means includes: when the speed ratio is the maximum speed ratio side and the target speed ratio is 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 than normal by the failure determination means, for example, the drive to the speed reduction ratio side is performed based on the driver's speed change request, and the responsiveness is not deteriorated. Failures can be detected without affecting the state.
[0016]
In the control device for a belt-type continuously variable transmission according to the sixth aspect, if the engine speed is equal to or higher than the speed at which the hydraulic pressure can be generated, the hydraulic pressure required to determine the failure is secured, and the failure is reliably detected. Can be detected.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 includes a primary pulley 10 on an input shaft side and an output shaft 13 as a pair of variable pulleys. Is provided with a secondary pulley 11 connected to the secondary pulley. 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 gear ratio of the continuously variable transmission 5 and the contact frictional force of the V-belt are controlled by a hydraulic control unit (hydraulic CU) 100 that responds to a command from a 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 outputs from sensors and the like described below.
[0021]
The primary pulley 10 of the continuously variable transmission 5 has a fixed conical plate 10b that rotates integrally with the input shaft, a V-shaped pulley groove disposed opposite to the fixed conical plate 10b, and a primary pulley cylinder. It is composed of a movable conical plate 10a that 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 has a fixed conical plate 11b that rotates integrally with the output shaft 13 and a V-shaped pulley groove that is disposed to face the fixed conical plate 11b, and is connected to the secondary pulley cylinder chamber 11c. It is composed of a movable conical plate 11a that can be displaced in the axial direction according to the hydraulic pressure (secondary pressure) that acts.
[0023]
Here, the primary pulley cylinder chamber 10c and the secondary pulley cylinder chamber 11c are set to have the same 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 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 to change the contact radius with the V-belt 12, so that the gear ratio between the primary pulley 10 and the secondary pulley 11 is changed. Can be changed continuously.
[0025]
The gear ratio of the continuously variable transmission 5 and the contact frictional force of the V-belt 12 are controlled by the hydraulic CU 100.
[0026]
As shown in FIG. 2, the hydraulic pressure CU 100 is controlled by the line pressure P discharged from the oil pump 22. _L Pressure regulator valve 60 (corresponding to the pressure regulating valve described in the claims) for controlling pressure, a shift control valve 30 for controlling the hydraulic pressure of the primary pulley cylinder chamber 10c (hereinafter, primary pressure), and supply to the secondary pulley cylinder chamber 11c. The pressure reducing valve 61 that controls the pressure (hereinafter, secondary pressure) is a main component.
[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 a primary pulley 10 connected to the other end of the servo link 50. The feedback of the groove width, that is, the actual gear ratio is received from the movable conical plate 10a.
[0028]
The line pressure control is constituted by a pressure regulator valve 60 provided with a solenoid for adjusting the oil pressure from the oil pump 22, and based on a command (for example, a duty signal or the like) 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 _L Are supplied to a shift 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 a shift actuator described in the claims) driven in response to a shift command signal from the CVTCU 20, and a servo link responsive to the step motor 40. The spool 31 of the shift control valve 30 is driven in accordance with the displacement of the shift control valve 50, and the line pressure P supplied to the shift control valve 30 _L Is adjusted to supply the primary pressure to the primary pulley 10, and the groove width is variably controlled to be set to a predetermined gear ratio (corresponding to a mechanical feedback mechanism described in claims).
[0031]
The shift control valve 30 adjusts the primary pressure by sucking and discharging the hydraulic pressure to and from the primary pulley cylinder chamber 10c by the displacement of the spool 31, so as to attain the target gear ratio commanded by the drive position of the step motor 40. When the shift is actually completed, the spool 31 is closed by receiving the displacement from the servo link 50.
[0032]
Here, in FIG. 1, the CVTCU 20 includes a primary pulley speed sensor 26 for detecting the rotation speed of the primary pulley 10 of the continuously variable transmission 5, a secondary pulley speed sensor 27 for detecting the rotation speed of the secondary pulley 11, and a secondary pulley 11. A signal from a hydraulic pressure sensor 28 for detecting a secondary pressure applied to the cylinder chamber 11c (corresponding to a secondary pulley hydraulic pressure detecting means described in claims) and a signal from an inhibitor switch 23 (corresponding to a range position detecting means described in claims). The stroke (or the opening of the accelerator pedal) from the operation amount sensor 24 (corresponding to the accelerator pedal opening detecting means according to the claims) corresponding to the operation amount of the accelerator pedal operated by the driver and the oil temperature From the sensor 25 (corresponding to the oil temperature detecting means described in the claims), the oil temperature of the continuously variable transmission 5 is determined. The contact friction force of the gear ratio or the V-belt 12 crowded viewed variably controlled. Further, a signal from an engine speed sensor 29 (corresponding to an engine speed detecting means described in claims) that detects the engine speed is input to the CVTCU 20 via the ECU 21.
[0033]
The CVTCU 20 determines a target gear ratio according to the vehicle speed and the stroke of the accelerator pedal, and drives a step motor 40 to control the actual gear ratio toward the target gear ratio. The pulley pressure (hydraulic) control unit 202 controls the thrust (contact frictional force) of the primary pulley 10 and the secondary pulley 11 according to the oil temperature, the shift speed, and the like.
[0034]
The pulley pressure control unit 202 calculates the line pressure P based on the input torque information, the gear ratio based on the primary pulley rotation speed and the secondary pulley rotation speed, and the oil temperature. _L Is determined, and the solenoid of the pressure regulator valve 60 is driven so that the line pressure P _L Control. In addition, a target value of the secondary pressure is determined, the solenoid of the pressure reducing valve 61 is driven according to the detection value and the target value of the hydraulic pressure 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 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 controlled by a line pressure P. _L FIG. 3 together with the control circuit of FIG.
[0036]
Line pressure P by pressure regulator valve 60 _L The surplus oil remaining 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 reduce the excess oil in the circuit 71 to a predetermined clutch base pressure P _co Adjust the pressure.
[0037]
The pressure regulator valve 60 and the clutch regulator valve 70 control the control pressure P generated by the 2-way linear solenoid 80 in accordance with the duty D based on a constant pilot pressure from a pilot valve (not shown). _s That is, in response to the 2-way linear solenoid drive duty D, the line pressure P _L And clutch base pressure P _co Control pressure P _s That is, according to the drive duty D of the two-way linear solenoid 80,
For example, the control is performed based on the map shown in FIG.
[0038]
By the way, line pressure P _L Is the minimum value P according to the 2-way linear solenoid drive duty D _LMIN And the highest value P _LMAX And the clutch base pressure P _CO Is the minimum value P according to the 2-way linear solenoid drive duty D _CMIN And the highest value P _CMAX And changes as shown.
[0039]
Clutch base pressure P _CO Is supplied to the select switching valve 90. The select switching valve 90 has a clutch base pressure P in the forward range. _CO Is supplied to the forward clutch 8 and its engagement pressure P _c And the engagement pressure P of the reverse brake 9 _b Drain. In the reverse range, the clutch base pressure P _co Is supplied to the reverse brake 9 and the engagement pressure P _b And the engagement pressure P of the forward clutch 8 _c Drain. Further, in the parking / parking range, the clutch base pressure P _co , The engagement pressure P of the forward clutch 8 _c And the engagement pressure P of the reverse brake 9 _b Drain 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, actuate accumulator springs 81b and 91b in one direction, and apply a clutch base pressure P in a direction opposite to these. _co Act as an accumulator back pressure.
[0041]
Therefore, the accumulators 81 and 91 provide the clutch base pressure P acting as the accumulator back pressure. _co Corresponding to the engagement pressure P of the forward clutch 8 _c And the engagement pressure P of the reverse brake 9 _b Can be transiently controlled.
[0042]
Next, the operation will be described.
[Normal shift control process]
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 rotation speed detected by the primary pulley speed sensor 26 and the secondary pulley rotation 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. The 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, a required secondary pressure (required secondary 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 speed ratio (Od side), the lower the hydraulic pressure, and the higher the speed ratio (Lo side), the higher the hydraulic pressure. If the input torque is large, the hydraulic pressure is high, and if the input torque is small, The hydraulic pressure is set low, and is set in advance.
[0046]
In step S4, a 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 speed 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 input torque, the lower the hydraulic pressure. Thus, the gear ratio 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, the magnitude relationship between the required primary pressure and the required secondary pressure may be reversed depending on the input torque.
[0047]
Next, in step S5, the primary pressure operation amount, which is the 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 the oil pressure) set according to the characteristic of the shift control valve 30, and the characteristic of the pressure loss is not completely proportional to the oil pressure. Value.
[0048]
In step S6, the magnitude relationship between the primary pressure manipulated variable and the required secondary pressure obtained in step S3 is compared and determined. When the primary pressure operation amount is larger, the process proceeds to step S7, and when the required secondary pressure is equal to or more than the primary pressure operation amount, the process proceeds to step S8.
[0049]
In step S7, the line pressure P _L This control is ended with the line pressure operation amount, which is the target value of, as the primary pressure operation amount.
[0050]
In step S8, this control is ended with the line pressure operation amount as a necessary secondary pressure.
[0051]
As described above, after the larger of the primary pressure operation amount and the required secondary pressure is determined as the line pressure operation amount (target oil pressure), the control amount (such as the duty signal) for driving the solenoid of the pressure regulator valve 60 is determined. After the conversion, the pressure regulator valve 60 is driven.
[0052]
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the case where the pressure regulator valve 60 for adjusting the line pressure is stuck to the maximum output side (hereinafter, referred to as MAX side) is detected. The necessity of detecting the MAX side sticking will be described.
In the configuration of the above-described embodiment, the hydraulic pressure supplied to the primary pulley cylinder chamber 10c is supplied via the shift control valve 31. On the other hand, the secondary pulley cylinder chamber 11c 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, if the line pressure is always high, the clamping pressure of the belt or the like becomes too high, and the frictional force during torque transmission may deteriorate fuel efficiency.
[0053]
[Line pressure failure judgment control when vehicle is stopped]
FIG. 8 is a flowchart showing the control contents of the line pressure fail determination control.
[0054]
In step 101, a range signal, a vehicle speed, an accelerator pedal stroke, an engine speed, an oil temperature, a fail 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 the condition is satisfied, the process proceeds to step 103, and otherwise, the present control is terminated (corresponding to a failure determination permission means described in 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 the accelerator is not depressed (state where the driver does not intend to start)
・ The engine speed is higher than the speed at which line pressure can be output.
・ Oil temperature is within a predetermined oil temperature range (because the viscosity may be high and the controllability may decrease at low temperatures, and the oil balance may be insufficient at high temperatures).
-Each solenoid, oil pressure sensor 28 and each rotation sensor (26, 27, 29) have not failed
Only when all of the above conditions are satisfied, it is determined that a safe state is ensured even if the hydraulic control is controlled to a state different from the normal state, and a failure determination is permitted (corresponding to claims 2 and 3).
[0056]
In step 103, the MIN command value for minimizing 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 for controlling the secondary hydraulic pressure.
[0058]
In step 105, the first timer is counted up.
[0059]
In step 106, the timer count value is set to a predetermined value τ. ₀ Is greater than or equal to a predetermined time τ. ₀ Assuming that the above has elapsed, the process proceeds to step 107, and otherwise the count of the first timer 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 detection value of the oil pressure sensor 28 is larger than a predetermined value A. If the absolute value is larger, the process proceeds to step 108;
[0061]
In step 108, the second timer is counted up.
[0062]
In step 109, the second timer count value is set to a predetermined value τ. ₁ It is determined whether the value is larger than the value. If the value 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 that controls the line pressure has a MAX sticking failure (corresponding to claim 1). Steps 103 to 110 correspond to a failure determination permission unit described in claims.
[0064]
The above control contents will be described based on the time chart of FIG.
At time t1, when the failure determination permission condition is satisfied, a line pressure MIN control command is output in step 103, and in step 104, the supply hydraulic pressure to the secondary cylinder chamber 11c is reduced by the pressure reducing valve 61 so that the line pressure is supplied as it is. The drain amount is 0, that is, a MAX command is output. In the belt-type continuously variable transmission according to 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 pressure sensor 28 that detects the hydraulic pressure of the secondary pulley cylinder chamber 11c.
[0065]
A predetermined time τ during which the failure determination permission condition is satisfied and the oil pressure detected by the oil pressure sensor 28 is stabilized ₁ , That is, the oil pressure is not detected until time t2. And a predetermined time τ ₁ After the lapse of time, the oil pressure of the oil pressure sensor 28 is detected from time t2, and a deviation between the detected oil pressure and the MIN pressure that is the line pressure command value is detected. The state in which this deviation is equal to or greater than a predetermined amount A is a predetermined time τ ₂ If the pressure is continuously detected at time t3, a high line pressure is supplied even though the MIN pressure is commanded as the line pressure command value, and the pressure regulator valve 60 is stuck at MAX. And a failure is determined.
[0066]
As described above, even if the hydraulic pressure sensor for directly detecting the line pressure is not provided, and only the hydraulic pressure sensor for detecting the hydraulic pressure of the secondary pulley cylinder chamber 11c is provided, the line pressure MAX-side sticking is detected. This makes it possible to prevent deterioration of fuel efficiency 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 pressure 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 pressure sensor 28, the primary pressure for detecting the hydraulic pressure of the primary cylinder chamber 10c is provided. The difference is that a hydraulic pressure sensor 32 (corresponding to a primary pulley hydraulic pressure detecting means described in claims) is provided. The other parts are basically the same as those of the first embodiment, and the description is omitted.
[0068]
In the second embodiment, as in the first embodiment, the case where the pressure regulator valve 60 for adjusting the line pressure is stuck to the maximum output side (hereinafter referred to as the MAX side) is detected. The second embodiment is different from the second embodiment in that the detection control is performed during traveling while the detection control is performed when the vehicle is stopped.
[0069]
[Line pressure failure judgment control during vehicle running]
FIG. 11 is a flowchart showing the control contents of the line pressure fail determination control.
[0070]
In step 201, the actual gear ratio, the target gear ratio, the engine speed, the secondary cylinder chamber oil pressure, and the fail flags of the solenoids and sensors are read.
[0071]
In step 202, it is determined whether or not the failure determination permission condition is satisfied. When the condition is 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 gear ratio is equivalent to overdrive, as shown in the gear ratio-primary pressure map of FIG. 7, the required primary pressure is low, and accordingly, the line pressure is also controlled to a low value. 5).
・ Target gear ratio <predetermined gear ratio (equivalent to overdrive)
This is because when the target gear ratio is equivalent to overdrive, it can be determined that the shift state is a steady state because it is equivalent to overdrive at the present time (corresponding to claim 5).・ No shift decision
If the vehicle is not running steady at a high gear ratio without crossing the gear shift line in the gear shift map, the gear ratio must be changed according to the driver's intention, and the response by driving the stepping motor overstroke is required. This is to prevent delay.
・ Engine speed> Predetermined value
This is because if the engine speed is equal to or higher than the predetermined value, a state in which a sufficient oil pressure is generated is secured in terms of the oil balance.
・ Secondary oil pressure <Predetermined value
The belt-type continuously variable transmission performs gear shifting with the balance of the belt clamping force of the primary pulley and the secondary pulley, and if the secondary hydraulic pressure is high and if a lower line pressure is supplied to the primary pulley as it is, the gear may shift. It is.
-Each solenoid, oil pressure sensor 28, each rotation sensor (26, 27, 29) and the step motor are not failed
Only when all of the above conditions are satisfied, it is determined that a safe state is secured even if the hydraulic control is controlled to a state different from the normal state, and the failure determination is permitted (the failure determination permission means according to 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 set to a predetermined value τ. ₀ Is greater than or equal to a predetermined time τ. ₀ Assuming that the above has elapsed, 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 detection value of the primary oil pressure sensor 32 is larger than a predetermined value A. If the absolute value is larger than the predetermined value A, the process proceeds to step 207; .
[0076]
In step 207, the second timer is counted up.
[0077]
In step 208, the second timer count value is set to a predetermined value τ. ₁ It is determined whether the value is larger than the value. If the value 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 has a MAX sticking failure. Steps 203 to 209 correspond to the failure determination permission means described in the claims.
[0079]
The above control contents 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 (corresponding to claim 4).
[0080]
Here, the reason for driving the step motor to the overstroke position will be described. FIG. 13 is a diagram illustrating a schematic diagram of a mechanical feedback mechanism for speed change control. When shifting the gear ratio to the Hi side, the groove width of the primary pulley is reduced. Therefore, the hydraulic pressure is supplied to the primary pulley cylinder chamber 10c. First, the step motor 40 is moved rightward 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, so that 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 drawing, and again shuts off the line pressure port. Therefore, the supply of the hydraulic pressure is stopped, and the shift is completed.
[0081]
The state in which the failure detection is permitted in the second embodiment is a steady running in a high gear ratio (overdrive) state. At this time, the groove width of the primary pulley is in the narrowest state, and the gear ratio does not change even if the hydraulic pressure is further supplied. Therefore, the step motor 40 is driven to the overstroke position, the line pressure is directly supplied to the primary pulley cylinder chamber 10c at a high speed ratio, and the line pressure can be detected by the primary hydraulic sensor 32.
[0082]
A predetermined time τ during which the failure determination permission condition is satisfied and the hydraulic pressure detected by the primary hydraulic pressure sensor 32 is stabilized ₁ , That is, the oil pressure is not detected until time t2. And a predetermined time τ ₁ After 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. The state in which this deviation is equal to or greater than a predetermined amount A is a predetermined time τ ₂ If the detection is continued, 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 at MAX, and a failure is determined.
[0083]
As described above, the primary pressure sensor 32 that detects the hydraulic pressure of the primary pulley cylinder chamber 10c does not include the hydraulic pressure sensor that directly detects the line pressure, and may detect the MAX side sticking of the line pressure during traveling. This makes it possible to prevent deterioration of fuel efficiency due to an increase in line pressure.
[0084]
The embodiment of the present invention, the first embodiment, and the second embodiment 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. Even a 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 for controlling engagement and release of a forward clutch and a reverse brake by ON / OFF of an engagement pressure together with a line pressure control circuit in the first embodiment.
FIG. 4 is a diagram showing a relationship between a solenoid drive duty, a line pressure, and a clutch base pressure in the first embodiment.
FIG. 5 is a flowchart illustrating 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 a required secondary pressure according to a gear ratio and an input torque in the first embodiment.
FIG. 7 is a map of a required primary pressure according to a gear ratio and an input torque in the first embodiment.
FIG. 8 is a flowchart illustrating control contents of a line pressure fail determination control in the first embodiment.
FIG. 9 is a time chart showing a line pressure fail determination control in the first embodiment.
FIG. 10 is a conceptual diagram of a hydraulic control unit and a CVT control unit in a second embodiment.
FIG. 11 is a flowchart illustrating control contents of a line pressure fail determination control in a second embodiment.
FIG. 12 is a time chart illustrating a line pressure fail determination control in the second embodiment.
FIG. 13 is a schematic diagram showing the position of a shift control valve when the stepping motor is overstroke in the second embodiment.
[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 Oil pressure sensor
29 Engine speed sensor
30 Shift control valve
31 spool
32 Primary oil pressure sensor
40 step motor
50 Servo link
60 Pressure regulator valve (pressure regulating valve)
61 Pressure reducing valve
70 Clutch regulator valve
71 circuits
80 2-way linear solenoid
81 accumulator
81a Accumulated piston
81b Accumulator spring
90 Select switching valve 90
91 Accumulator
91a Accumulated 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 pressure 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 for holding the V-belt,
A shift control valve that controls a hydraulic pressure supplied from the pressure regulating valve to supply the primary pulley or the secondary pulley, and changes a groove width of the pulley to change a gear ratio;
Secondary pulley oil pressure detection means for detecting the oil pressure of the secondary pulley,
A pressure reducing valve that reduces the hydraulic pressure of the secondary pulley based on a control signal;
Speed ratio control means for controlling the speed change control valve and the pressure reducing valve so as to have a target speed ratio set based on the vehicle speed and the throttle opening;
In the control device of the belt-type continuously variable transmission having
Provision of a pressure regulating valve failure determining means for determining the failure of the pressure regulating valve,
The pressure regulating valve failure determination means outputs a command to minimize the amount of pressure reduction of the pressure reducing valve to the speed ratio control means, and outputs a command to regulate the pressure to the minimum pressure to the pressure regulating valve control means. A control device for a belt-type continuously variable transmission, characterized in that when the deviation between the oil pressure detected by the oil pressure detecting means and the minimum pressure is equal to or more than a predetermined value, it is determined that a failure has occurred. The control device for a belt-type continuously variable transmission according to claim 1,
Provision of a failure determination permission means for permitting / prohibiting the pressure regulator failure determination,
The failure determination permitting means determines the failure only when the vehicle is in a stopped state, 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 the power transmission. A control device for a belt-type continuously variable transmission, wherein the control device is configured to permit the control of the transmission. The control device for a belt-type continuously variable transmission according to claim 1 or 2,
Range position detecting means for detecting a range position of a select lever selected by a driver;
Vehicle speed detecting means for detecting a vehicle speed;
Accelerator pedal opening detection means;
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 permitting means is such that the detected range position is a neutral range or a parking range, the detected vehicle speed is a value that can be determined to be a vehicle stop, the accelerator pedal is not depressed, and the engine speed is lower. A control device for a belt-type continuously variable transmission, wherein a failure determination is permitted when the rotation speed is equal to or higher than a rotation speed at which hydraulic pressure can be generated and the oil temperature is within a region where controllability is ensured. A pressure regulating valve for regulating the hydraulic pressure supplied from the hydraulic pressure 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 for holding the V-belt,
A shift actuator driven based on a shift command;
A first port connected to a hydraulic supply oil passage for supplying a hydraulic pressure adjusted by the pressure regulating valve; a second port connected to a hydraulic supply / discharge oil passage communicating with a cylinder chamber of the primary pulley; A third port connected to a discharge oil passage for discharging oil from the cylinder chamber, and a first port and a second port when the speed change actuator is driven on a speed increasing side from a blocking position for blocking communication between the ports. A spool that moves to a deceleration position that communicates with the second port and the third port when driving on the deceleration side, and controls a hydraulic pressure that is supplied to a cylinder chamber of the primary pulley. A speed change control valve,
A mechanical feedback mechanism that detects a groove width of the primary pulley and returns the spool driven by the speed change actuator to a blocking position;
Primary pulley oil pressure detection means for detecting the oil pressure of the primary pulley,
Speed ratio control means for controlling the speed change actuator such that the target speed ratio is set based on the vehicle speed and the throttle opening;
Speed ratio detecting means for detecting a speed ratio,
In the control device of the belt-type continuously variable transmission having
Provision of a pressure regulating valve failure determining means for determining the failure of the pressure regulating valve,
The pressure regulating valve failure determination unit is configured to instruct the speed ratio control unit to drive the speed change actuator in a direction to connect the first port and the second port when the detected speed ratio is the maximum speed ratio side. And when the deviation between the oil pressure detected by the primary pulley oil pressure detecting means and the command value of the pressure regulating valve control means is equal to or greater than a predetermined value, means for judging a failure is provided. Control device for step transmission. The control device for a belt-type continuously variable transmission according to claim 4,
Provision of a failure determination permission means for permitting / prohibiting the pressure regulator failure determination,
The belt type continuously variable transmission, wherein the failure determination permitting means permits the failure determination when the speed ratio is on the maximum speed increase ratio side and the target speed ratio is on the maximum speed increase ratio side. Control device. The control device for a 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 means permits the failure determination when the engine rotation speed is equal to or higher than a rotation speed at which hydraulic pressure can be generated.

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