JP2001330134A - Control device for vehicular continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicular continuously variable transmission suitably preventing a slip of a power transmitting member even when an abnormal condition occurs in an oil temperature sensor, engaging control of a clutch, or a sensor detecting an operational position of a shift lever. SOLUTION: When an abnormal condition of an oil temperature sensor 78 is determined by an oil temperature sensor abnormality determining means 98, pinch pressure controlled by a pinch pressure controlling means 92 is increased by a pinch pressure increasing means 104. Therefore, a slip of a transmission belt 48 is suitably prevented even when the abnormal condition occurs in the oil temperature sensor 78.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a continuously variable transmission for a vehicle, and more particularly, to a technique for preventing insufficient clamping pressure associated with an abnormality in a sensor used for regulating the clamping force of a power transmission member.

[0002]

2. Description of the Related Art In a continuously variable transmission for a vehicle that transmits power through friction between a power transmission member for transmitting power and a power transmission member, when a sensor for detecting the rotation speed of a prime mover is abnormal, the power transmission member is used. There has been proposed a control device for a continuously variable transmission for a vehicle of a type in which a squeezing pressure on the power transmission member is increased to a maximum value to prevent the power transmission member from slipping. For example,
This is the control device for a continuously variable transmission for a vehicle described in Japanese Patent Application Laid-Open No. H8-4797. According to this, in the belt-type continuously variable transmission in which the transmission belt is wound around the pair of variable pulleys whose effective diameters are variable, when the abnormality of the engine rotation speed sensor is determined, the belt clamping pressure is changed to the given speed. By setting the maximum value with respect to the ratio, slip of the transmission belt is prevented.

[0003]

According to the above-described control apparatus for a continuously variable transmission for a vehicle, when controlling the belt rotation to a necessary and sufficient pressure based on the input torque and the gear ratio, the engine rotation speed is reduced. If the detection becomes impossible, it becomes impossible to calculate the input torque, which is one of the parameters required for the belt squeezing pressure control, and it is effective against the inconvenience that the belt squeezing pressure is reduced and the transmission belt slips. It is. However, there is a disadvantage that the inconvenience of belt clamping pressure control related to other sensor abnormalities cannot be dealt with at all. For example, in a vehicle that performs squeezing pressure control of a continuously variable transmission based on hydraulic oil temperature, if an abnormality occurs in an oil temperature sensor, squeezing pressure may be insufficient. Further, when a continuously variable transmission is arranged in series with the clutch in the power transmission path of the vehicle, if an abnormality occurs in the engagement control of the clutch, the clamping pressure may be insufficient. Further, when the clamping force of the power transmission member of the continuously variable transmission is changed in accordance with the operating position of the shift lever for selecting the travel range, if an abnormality occurs in the sensor that detects the operating position of the shift lever, Insufficient pressure may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to detect an abnormality in an oil temperature sensor, clutch engagement control, or a sensor for detecting a shift lever operation position. It is an object of the present invention to provide a control device for a continuously variable transmission for a vehicle, in which slippage of a power transmission member is preferably prevented even if it occurs.

[0005]

A first aspect of the present invention to achieve the above object is to transmit power through friction between a power transmission member for transmitting power. In the continuously variable transmission for a vehicle, the clamping force on the power transmission member is controlled as necessary and sufficiently, and the clamping force on the power transmission member is determined based on the operating oil temperature of the continuously variable transmission detected by an oil temperature sensor. (A) an oil temperature sensor abnormality determining means for determining whether the oil temperature sensor is abnormal, and (b) If the oil temperature sensor abnormality determining means determines that the oil temperature sensor is abnormal, the oil temperature sensor abnormality determining means includes a clamping pressure increasing means for increasing the clamping pressure controlled by the clamping pressure control means.

[0006]

In this way, when the oil temperature sensor abnormality judging means judges that the oil temperature sensor is abnormal, the clamping pressure controlled by the clamping pressure control means by the clamping pressure increasing means is reduced. Since it is increased, even if an abnormality occurs in the oil temperature sensor, slippage of the power transmission member is suitably prevented.

[0007]

A second aspect of the present invention to achieve the above-mentioned object is to provide a second aspect of the present invention in which a frictional engagement device is disposed in series between a prime mover and drive wheels. A continuously variable transmission for a vehicle that transmits power through friction between the power transmission member and a power transmission member for transmitting power, the vehicle comprising a clamping force control unit that controls a clamping force on the power transmission member in a necessary and sufficient manner. A control device for a vehicle continuously variable transmission, wherein (a) friction engagement device abnormality determination means for determining whether the engagement and release operation of the friction engagement device is abnormal, (b) When the friction engagement device abnormality determination unit determines that the friction engagement device is abnormal, the friction engagement device abnormality determination unit includes a squeezing pressure increasing unit that increases the squeezing pressure controlled by the squeezing pressure control unit.

[0008]

In this way, when the friction engagement device abnormality judging unit judges that the friction engagement device is abnormal, the friction engagement device is controlled by the clamping force control unit by the clamping force increasing unit. Since the squeezing pressure is increased, an abnormality occurs in the frictional engagement device arranged in series with the continuously variable transmission in the power transmission path between the prime mover and the drive wheels, and the transmission torque becomes excessive. Even if the torque limiter function is impaired, slippage of the power transmission member is suitably prevented.

[0009]

A third aspect of the present invention to achieve the above-mentioned object is that power is transmitted via friction between a power transmission member for transmitting power. A continuously variable transmission for a vehicle, comprising: a squeezing force control means for controlling squeezing force on a power transmission member thereof necessary and sufficiently, and correcting the squeezing force according to a switching position by a shift lever. A control device for a step transmission, wherein (a) a shift lever operation position detection abnormality determination unit that determines whether a shift lever operation position sensor for detecting an operation position of the shift lever is abnormal, b)
When the shift lever operating position detection abnormality determining means determines that the shift lever operating position sensor is abnormal, the pressing lever control means increases the pressing force controlled by the pressing force control means. .

[0010]

According to the third aspect of the present invention, when the shift lever operating position detection abnormality determining means determines that the shift lever operating position sensor is abnormal, the clamping pressure increasing means causes the clamping lever control means to determine whether the shift lever operating position sensor is abnormal. Since the controlled squeezing pressure is increased, even if an abnormality occurs in the detection of the operation position of the shift lever and the squeezing pressure controlled corresponding to the actual switching position is to be reduced, the squeezing force is increased by the squeezing force increasing means. The slippage of the power transmission member is suitably prevented by the applied clamping pressure.

[0011]

Another aspect of the present invention is preferably that the first invention,
In the second invention and the third invention, the continuously variable transmission preferably includes a pair of input shafts and an output shaft parallel to each other, a fixed rotating body fixed to the pair of the input shaft and the output shaft, and a fixed rotating body thereof. A pair of variable pulleys, each having a variable effective diameter, comprising a pair of input shafts and a movable rotary body provided on the output shaft so as to be non-rotatable around the shafts and movable in the axial direction so as to form a V groove therebetween. And a transmission belt wound around the pair of variable pulleys, and a pair of input-side hydraulic cylinders and output-side hydraulic cylinders for applying a thrust to the movable rotator toward the solid rotator. Machine. In this way, even if an abnormality occurs in the oil temperature sensor, the clutch engagement control, or the sensor that detects the operating position of the shift lever, the transmission belt of the belt-type continuously variable transmission can be prevented from slipping. Is done.

Preferably, in the first invention,
In order to cope with an increase in the friction (friction resistance) of the prime mover or the forward / reverse switching device as the hydraulic oil (lubricating oil) becomes lower in temperature, the squeezing pressure control means increases the power transmission member as the hydraulic oil temperature becomes lower. To prevent the power transmission member from slipping at the time of decelerating travel or the like, and the clamping force increasing means increases the pressure to a value corresponding to the lowest value in the temperature range of the hydraulic oil. This is to increase the clamping pressure. With this configuration, when the oil temperature sensor is abnormal, the clamping force is corrected to a value on the side of the temperature range where slippage of the power transmission member is least likely to occur, so that slippage of the power transmission member is suitably prevented. Is done.

Preferably, in the second invention,
A forward / reverse switching device is disposed in series on a power transmission path between the prime mover and the continuously variable transmission, and the friction engagement device is a forward clutch or a reverse brake of the forward / reverse switching device, By controlling the transmission torque to be necessary and sufficient to transmit the output torque of the prime mover, the abnormal torque is transmitted to the continuously variable transmission when the abnormal torque generated from the drive wheels due to the rough road traveling is transmitted. It functions as a torque limiter that prevents transmission of the abnormal torque so that it is not added. In this way, even if the abnormal torque is transmitted to the continuously variable transmission without being absorbed by the forward clutch or the reverse brake due to the above control failure, the clamping force of the power transmission member is increased. Slip of the power transmission member due to this is suitably prevented.

[0014] Preferably, in the second invention,
The friction engagement device is a hydraulic friction engagement device, and the friction engagement device abnormality determination unit determines whether an electromagnetic control valve that controls the engagement pressure of the hydraulic friction engagement device has failed. Is what you do. By doing so, the clamping force of the power transmission member is increased when transmitting abnormal torque of the hydraulic friction engagement device.

Preferably, in the third invention,
The shift lever operation position detection abnormality determination means determines that the output of the shift lever operation position sensor is in the non-travel range even though the shift lever has been operated from the non-travel range (eg, N range) to the travel range (eg, D range). The clamping pressure increasing means, from the clamping pressure controlled by the clamping pressure control means, the difference between the clamping pressure in the traveling range and the clamping pressure in the non-traveling range is equal to or greater than To increase the value. The difference is preferably a maximum difference between a plurality of non-travel ranges and a plurality of travel ranges.
According to this configuration, the value of the difference between the clamping pressure in the traveling range and the clamping pressure in the non-traveling range can be increased by the clamping force increasing means, so that the power transmission member caused by the abnormality of the shift lever operation position sensor can be increased. Sliding is suitably prevented.

[0016]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a skeleton diagram of a power transmission device 10 including a vehicle belt-type continuously variable transmission 18 to which a control device according to an embodiment of the present invention is applied. The power transmission device 10 is suitably employed, for example, in a laterally mounted FF (front engine / front drive) driven vehicle, and includes an engine 12 which is an internal combustion engine used as a power source for traveling. The output of the engine 12 is supplied from a torque converter 14 to a forward / reverse switching device 16 and a belt-type continuously variable transmission (C).
VT) 18, and transmitted to the differential gear device 22 via the reduction gear 20, and distributed to the left and right drive wheels 24 </ b> L and 24 </ b> R. The belt-type continuously variable transmission 18 is provided with left and right driving wheels (for example, front wheels) 24L,
It is provided in a power transmission path leading to 4R.

The torque converter 14 is used for the engine 1
The pump impeller 14p connected to the second crankshaft, the turbine impeller 14t connected to the forward / reverse switching device 16 via the turbine shaft 34, and a non-rotating member rotatably supported via a one-way clutch. And a fixed-wing wheel 14s for transmitting power via fluid. A lock-up clutch (direct coupling clutch) 26 for integrally connecting the pump impeller 14p and the turbine impeller 14t so as to be able to rotate integrally with each other is provided between the pump impeller 14p and the turbine impeller 14t. Is provided.

The forward / reverse switching device 16 is constituted by a double pinion type planetary gear device. The turbine shaft 34 of the torque converter 14 is connected to the sun gear 16 s, and the input shaft 36 of the belt type continuously variable transmission 18. Is carrier 1
6c. Then, when the shift lever 67 is operated to the forward traveling range such as the D, 2, or L range, the hydraulic forward clutch 38 disposed between the carrier 16c and the sun gear 16s is engaged. The forward / reverse switching device 16 is integrally rotated so that the turbine shaft 34 is directly connected to the input shaft 36, and the driving force in the forward direction is transmitted to the drive wheels 24R and 24L. When the shift lever 67 is operated to the reverse travel range, which is the R range, the hydraulic reverse brake 40 disposed between the ring gear 16r and the housing is engaged, and the forward clutch 38 is released. Then, the input shaft 36 is rotated in the reverse direction with respect to the turbine shaft 34, and the driving force in the reverse direction is transmitted to the drive wheels 24R and 24L. The forward clutch 38 and the reverse brake 40 function as a hydraulic friction engagement device.

The belt-type continuously variable transmission 18 includes an input-side variable pulley 4 provided on the input shaft 36 and having a variable effective diameter.
2, an output variable pulley 46 provided on the output shaft 44 and having a variable effective diameter, and a transmission belt 48 wound around the V groove of the variable pulleys 42 and 46. Transmission belt 48 and variable pulley 4 functioning as
Power transmission is performed via frictional force between the inner wall surfaces of the V-grooves 2 and 46. Variable pulleys 42, 46
Is provided with an input-side hydraulic cylinder 42c and an output-side hydraulic cylinder 46c for changing the width of each V-groove, that is, the hanging diameter of the transmission belt 48, and is supplied to or from the hydraulic cylinder 42c of the input-side variable pulley 42. As the flow rate of the discharged hydraulic oil is controlled by the shift control valve device 50 (see FIG. 3) in the hydraulic control circuit 52, the V-groove width of both the variable pulleys 42 and 46 changes, and the transmission belt 48 is engaged. The diameter (effective diameter) is changed, and the speed ratio γ (= input-side rotation speed N _IN / output-side rotation speed N _OUT ) is continuously changed.

The hydraulic pressure P _B in the hydraulic cylinder 46c of the output-side variable pulley 46 corresponds to the squeezing pressure of the variable pulley 46 on the transmission belt 48 and the tension of the transmission belt 48, respectively. Since it is closely related to the tension, that is, the pressing force of the transmission belt 48 against the inner wall surfaces of the V-grooves of both the variable pulleys 42 and 46, it can also be called a belt tension control pressure, a belt clamping pressure control pressure, and a belt pressing force control pressure. In order to prevent the transmission belt 48 from slipping, the clamping pressure control valve 60 in the hydraulic control circuit 52 is
The pressure is regulated.

FIGS. 2 and 3 are diagrams showing an example of the hydraulic control circuit 52. FIG. 2 shows a circuit related to the pressure adjusting operation of the belt tension control pressure, and FIG. 3 shows a circuit related to the speed ratio control. Each is shown. In FIG. 2, the oil tank 5
Hydraulic oil refluxed 6 is pumped by a hydraulic pump 54 driven by the engine 12, after the pressure is regulated to a line pressure P _L by a not-shown line pressure regulating valve, a linear solenoid valve 58 and clamping pressure control valve 60 Supplied as source pressure. The linear solenoid valve 58 includes an electronic control device 66
By continuously controlling the exciting current from the hydraulic pump 54 (see FIG. 4), a control pressure P _S having a magnitude corresponding to the exciting current is generated from the hydraulic pressure of the hydraulic oil supplied from the hydraulic pump 54 to pinch it. It is supplied to the pressure control valve 60. Nipping pressure control valve 60
Generates a hydraulic pressure P _B that is increased as the control pressure P _S increases, and supplies the hydraulic pressure P _B to the hydraulic cylinder 46 c of the output-side variable pulley 46 so that the transmission belt 48 does not slip as much as possible. The clamping pressure on the transmission belt 48, that is, the tension of the transmission belt 48 is reduced. Its oil pressure P _B increases the frictional force between the accompanied in its raised and the belt clamping pressure or variable pulleys 42, 46 and the transmission belt 48.

[0023] The linear solenoid valve 58, while the oil chamber 58a of the control pressure P _S which is output therefrom at ON cutback valve 62 is supplied is provided, the cut-back valve 62 OFF times, to the oil chamber 58a are adapted to control pressure P _S supply is cut off by the oil chamber 58a of are opened to the atmosphere of, so that the time on the cut-back valve 62 characteristic of the control pressure P _S than when off is switched to the low-pressure side It has become. When the lock-up clutch 26 of the torque converter 14 is turned on (engaged), the cutback valve 62 is turned on by supplying a signal pressure P _ON from a solenoid valve (not shown).

Referring to FIG. 3, the transmission control valve device 50
Is an upshift control valve 50 _U that exclusively supplies the hydraulic oil of the line pressure P _L to the hydraulic cylinder 42 c of the input-side variable pulley 42 and controls the upshift speed by controlling the hydraulic oil flow rate; and The hydraulic cylinder 42
The downshift control valve 50D controls the downshift speed by controlling the flow rate of the hydraulic oil discharged from the control valve _50D.
It is composed of This up-shift control valve 50 _U
A spool valve 50 _Uv that opens and closes between a line oil passage _L that guides the line pressure P _L and the input side hydraulic cylinder 42 c, and a spring 50 that urges the spool valve 50 _Uv in the valve closing direction.
_Us and a control oil chamber 50 _Uc for guiding the control pressure output from the up-side solenoid valve 64 _U. Further, downshift control valve 50 _D is input hydraulic cylinder and drain oil passage D 42
a spool valve element 50 _Dv that opens and closes between is c, a spring 50 for biasing the spool valve element 50 _Dv in the closing direction
And _ds, and a control hydraulic chamber 50 _Dc for guiding a control pressure that is output from the down side the solenoid valve 64 _D. The up-side electromagnetic valve 64 _U and the down-side electromagnetic valve 64 _D, the electronic control unit 6
The control pressure continuously changed by the duty drive by the control unit 6 is supplied to the control oil chamber 50 _Uc and the control oil chamber 50 _Dc, and the speed ratio γ of the belt-type continuously variable transmission 18 is continuously increased to the up side and the down side. Change. Note that the shift-down control valve 50 _D, the line oil passage L and the input-side hydraulic cylinder 42c in the closed position of the spool valve element 50 _Dv
And a flow passage 61 having a small flow cross-sectional area is formed between the transmission gear 61 and the speed change ratio γ when the upshift control valve _50U and the downshift control valve _50D are both closed. In order to prevent this, restrict from line oil passage L
3. The working oil is slightly supplied through the one-way valve 65 and the flow passage 61.

The electronic control unit 66 shown in FIG.
The operation position detection sensor 68 for detecting the operation position of the
Operating position P_SHSignal indicating the ignition key
Ignition from the operated ignition switch 69
Signal indicating the on-key operation, the opening of the throttle valve 70
Of the accelerator pedal 71 that changes the_ACCDetect
Accelerator opening θ from the accelerator operation amount sensor 72_ACC
, The rotation speed N of the engine 12_ETo detect
The rotation speed N from the engine rotation speed sensor 73_EA sign of
No., vehicle speed V (specifically, rotation speed N of output shaft 44)_OUT)
Speed sensor (output side rotation speed sensor) 74
Signal representing the vehicle speed V, the input shaft rotation speed N of the input shaft 36.
_INInput shaft rotation from the input side rotational speed sensor 76 that detects
Rolling speed N _IN, The power transmission 10 or bell
Oil temperature T in the automatic transmission 18_OILDetect the oil
Hydraulic oil temperature T from temperature sensor 78_OILSignal representing the output
Pressure P of the hydraulic cylinder 46c of the side variable pulley 46_Bsand
That is, the actual belt clamping pressure control pressure P_BDetecting the pressure sensor
Its hydraulic pressure P from the_BSignals representing the
It is supposed to be.

The electronic control unit 66 includes a CPU, an RO,
M, a RAM, a so-called microcomputer including an input / output interface, and the like.
By performing signal processing in accordance with a program stored in the ROM in advance while utilizing the temporary storage function, the shift control and the clamping pressure control of the continuously variable transmission 18 are performed.
Specifically, in the shift control, for example, an accelerator operation amount representing an actual driver's required output amount, that is, an accelerator opening degree θ is obtained from a relationship (map) stored in advance shown in FIG.
Calculates a target rotational speed N _IN ^T based on _{AC C} (%) and the vehicle speed V (corresponding to the output rotational speed N _OUT), the actual input rotational speed N _IN coincides with the target rotational speed N _IN ^T By operating the transmission control valve device 50 as described above, the flow rate of the hydraulic oil supplied into the hydraulic cylinder 42c of the input-side variable pulley 42 or the hydraulic oil discharged from the hydraulic cylinder 42c is controlled. FIG. 5 shows, for example, a relationship determined in advance for operating the engine 12 along an optimal curve in which the output and the fuel consumption are optimal, wherein γ _max is the maximum gear ratio, and γ _min is the minimum gear ratio. Ratio.

In the belt squeezing pressure control, the electronic control unit 66 uses a predetermined relationship (map) to obtain a necessary and sufficient necessary oil pressure (a target oil pressure corresponding to an ideal belt squeezing pressure). A belt clamping pressure control pressure (target value) is calculated based on the accelerator operation amount θ _ACC corresponding to the actual input torque T _IN or the transmission torque of the belt type continuously variable transmission 18 and the actual gear ratio γ, and the belt clamping is performed. The squeezing pressure control valve 60 in the hydraulic control circuit 52 is adjusted to obtain a pressure control pressure.

Further, the electronic control unit 66 reduces the torque of the forward clutch 38 of the forward / reverse switching device 16 so that the torque transmission between the engine 12 and the drive wheels 24L and 24R is necessary and sufficient. Control. For example, in order to prevent transmission of abnormally large torque transmitted from the road surface through the drive wheels 24R and 24L by slipping of the forward clutch 38 and to prevent slipping of the transmission belt 48, the accelerator operation amount θ _{AC C} and the engine rotation speed are set. _NE
The torque of the forward clutch 38 is controlled by adjusting the engagement pressure of the forward clutch 38 so that an engagement torque higher than the output torque by a predetermined margin value is obtained. I do.

FIG. 6 is a functional block diagram for explaining a main part of the control function of the electronic control unit 66, that is, a belt clamping pressure control and the like. In FIG. 6, the shift control means 88
During the operation of the vehicle, the actual accelerator opening θ _{ACC is obtained} from a relationship (map) stored in advance shown in FIG. 5, for example.
(%) And calculates the target rotational speed N _IN ^T based on the vehicle speed V (corresponding to the output rotational speed N _OUT), so that the actual input rotational speed N _IN coincides with the target rotational speed N _IN ^T determining the shift control valve device 50 of the up-shift control valve 50 _U or down shift control valve 50 _D of the drive duty ratio D (%), by executing a feedback controlled to operate in its drive duty ratio D, the input side variable Pulley 42
Of the hydraulic oil supplied to the hydraulic cylinder 42c of the hydraulic cylinder 42c or the hydraulic oil discharged from the hydraulic cylinder 42c of the input-side variable pulley 42.

The clutch control means 90 controls the accelerator operation amount to prevent the transmission belt 48 from slipping by blocking the transmission of abnormally large torque transmitted from the road surface through the drive wheels 24R and 24L by the slip of the forward clutch 38. calculating the output torque of the engine 12 based on the theta _ACC and the engine rotational speed N _E, to control the engagement pressure of the forward clutch 38 as high engagement torque by a predetermined margin value can be obtained from the output torque , So that torque transmission between the engine 12 and the drive wheels 24L, 24R is necessary and sufficient.

The squeezing force control means 92 is provided with a necessary and sufficient hydraulic pressure (corresponding to an ideal belt squeezing pressure) to obtain a squeezing force on the transmission belt 48 as small as possible without causing slippage of the transmission belt 48. From the predetermined relationship (map) to obtain the actual input torque T _IN or the accelerator operation amount θ _ACC and the actual gear ratio γ corresponding to the transmission torque of the belt type continuously variable transmission 18 in order to obtain the target hydraulic pressure. Te belt clamping pressure control pressure (target value) is calculated P _B ^T, the actual belt clamping pressure control pressure P _B is the target value P _B ^T
So that the clamping pressure control valve 6 in the hydraulic control circuit 52
Adjust the pressure to zero. The above relationship is determined, for example, based on a theoretical value in steady running. Further, the clamping force control unit 92 is provided with an oil temperature correction section 94 for correcting the belt squeezing force control pressure P _B on the basis of the working oil temperature T _OIL detected by the oil temperature sensor 78. The oil temperature correcting means 94 is, for example, a belt-type continuously variable transmission 18.
In this case, the friction due to the viscosity of the hydraulic oil, which increases as the temperature decreases, increases, and the rotational resistance of the engine 12 and the forward / reverse switching device 16 increases during deceleration driving, so that the transmission belt 48
In order to prevent the occurrence of slip, the increase value P _UP determined from the relationship that the increase value P _UP of the belt clamping pressure control pressure P _B increases as the hydraulic oil temperature T _OIL decreases, is increased by the belt clamping pressure. It is added to the control pressure P _B. When the shift lever 67 is located in the non-traveling range such as the N or P range, the pinch control means 92 sets the shift lever 67 to the D position in order to increase the durability of the transmission belt 48. , as compared with the case that is is positioned running range such as R-range, and a non-driving range clamping pressure lowering means 96 to lower the belt squeezing force control pressure P _B by the predetermined value.

The oil temperature sensor abnormality judging means 98 judges whether or not the output signal from the oil temperature sensor 78 has become abnormal, based on the presence / absence of disconnection, short circuit, or characteristic change of the oil temperature sensor 78. Clamping pressure increasing unit 104, when an abnormality of oil temperature sensor 78 is determined by the oil temperature sensor abnormality determination section 98, clamping pressure P _B in the predetermined increased value P which is controlled by the clamping force control means 92 By adding _UP , the clamping pressure of the transmission belt 48 is increased. The increase value P _UP is desirably the belt clamping pressure control pressure P _B when the hydraulic oil temperature T _OIL reaches the minimum value (minimum temperature) T _{OILmin of the} change range in the oil temperature correction means 94.
A value corresponding to the maximum correction amount used to highly correct the pressure, or the maximum value of the variation range of the increase value P _UP due to the hydraulic oil temperature T _OIL is used, but the value or the maximum value corresponding to the maximum correction amount is not necessarily used. It is not always necessary to add a certain amount of increase value P _UP to the power transmission belt 4.
A certain effect can be obtained with respect to the prevention of slip of No. 8.

The friction engagement device abnormality determining means 100 determines whether or not the transmission torque of the hydraulic forward clutch 38, which is required and sufficiently controlled by the clutch control means 90, is abnormal. For example, it is determined by a well-known disconnection short-circuit detection circuit whether or not the torque of the forward clutch 38 has become abnormally high due to disconnection or short-circuit of an electromagnetic control valve in a hydraulic circuit that controls the engagement pressure of the forward clutch 38. Is done. Clamping pressure increasing unit 104, when the abnormality of the transmission torque of the forward clutch 38 is determined by the frictional engagement device abnormality determining means 100, a predetermined in clamping pressure P _B which is controlled by the clamping force control means 92 By adding the increase value P _UP , the clamping force of the transmission belt 48 is increased. This increase value P _UP is desirably a value corresponding to the maximum torque value of the torque change range of the forward clutch 38 by the clutch control means 90, that is, the maximum torque value.
The clamping pressure increase value at which the transmission belt 48 does not slip even when the torque 8 is transmitted is used, but the value does not necessarily need to correspond to the maximum torque amount, and an increase value P _UP of a certain magnitude is added. As a result, a certain effect can be obtained in terms of preventing the transmission belt 48 from slipping. Also, the reverse brake 40 is similar to the forward clutch 38,
Or abnormal or not by frictional engagement device abnormality determining means 100 is determined, the clamping pressure P _B is increased by the clamping pressure increasing means 104 if abnormal.

The shift lever operation position detection abnormality determination means 102 determines whether or not the shift lever operation position sensor 68 for detecting the operation position of the shift lever 67 is abnormally detected. For example, irrespective of whether the shift lever 67 has been operated to a driving range such as the D or R range due to a failure of the shift lever operating position sensor 68, N
It is determined that it is detected that the vehicle is located in a non-traveling range such as a range. When the shift lever operation position detection abnormality determination unit 102 determines that the shift lever operation position sensor 68 is abnormal, the squeezing pressure increasing unit 104 reduces the squeezing pressure P _B controlled by the squeezing pressure control unit 92. By applying a predetermined increase value P _UP , the clamping pressure of the transmission belt 48 is increased. As the increase value P _UP , a value corresponding to the maximum value of the squeezing pressure change width by the non-traveling range squeezing pressure lowering means 96 is preferably used, but it is not necessarily a value corresponding to the maximum value of the squeezing pressure change width. Alternatively, by adding a certain amount of increase value P _UP , a tentative effect can be obtained in terms of preventing the transmission belt 48 from slipping.

FIG. 7 is a flowchart for explaining a main part of the control operation of the electronic control unit 66, which is repeatedly executed at a predetermined cycle time. First, a step corresponding to the oil temperature sensor abnormality determination means 98 (hereinafter referred to as a step).
In step SA1, it is determined whether the output signal from the oil temperature sensor 78 has become abnormal based on the presence or absence of disconnection, short circuit, or characteristic change of the oil temperature sensor 78. If the determination in SA1 is affirmative, in SA2 corresponding to the clamping pressure increasing means 104, the oil temperature correcting means 94 _{sets the} operating oil temperature T _OIL to the minimum value (minimum temperature) T _{OILmin of the} change range. The increase value (maximum correction amount) P _UP used for correcting the belt clamping pressure control pressure P _B to be higher when becomes the following is added to the clamping pressure P _B controlled by the clamping force control means 92. The clamping pressure of the transmission belt 48 is increased. However, if the determination in SA1 is denied, SA2 is not executed and SA3 and subsequent steps are executed.

At SA3 corresponding to the friction engagement device abnormality judging means 100, the hydraulic forward clutch 3 which is required and sufficiently controlled in torque by the clutch control means 90 is provided.
8 is determined based on the occurrence of disconnection or short circuit of the electromagnetic control valve in the hydraulic circuit that controls the engagement pressure of the forward clutch 38, or
It is similarly determined whether the abnormality is 0. If the determination in SA3 is positive, in SA4 corresponding to the clamping pressure increasing unit 104, the on clamping pressure P _B which is controlled by the clamping force control unit 92, for example, the maximum torque value of the torque variation range of the forward clutch 38 by being added is increased value P _UP corresponding to, clamping pressure of the transmission belt 48 is increased. However, if the determination in SA3 is denied,
The above SA4 is not executed, and SA5 and subsequent steps are executed.

At SA5 corresponding to the shift lever operation position detection abnormality judging means 102, a shift lever operation position sensor 6 for detecting the operation position of the shift lever 67 is detected.
It is determined whether or not the detection abnormality is No. 8. If the determination at SA5 is yes, SA4 corresponding to the clamping pressure increasing unit 104, the on clamping pressure P _B which is controlled by the clamping force control unit 92, for example, the maximum value of the clamping pressure variation caused by the range change by being added is increased value P _UP corresponding to, clamping pressure of the transmission belt 48 is increased.

As described above, according to this embodiment, the oil temperature sensor 78 is determined by the oil temperature sensor abnormality determination means 98 (SA1).
If it is determined that the pressure is abnormal,
Since the squeezing pressure controlled by the squeezing force control means 92 is increased by (SA2), even if an abnormality occurs in the oil temperature sensor 78, slippage of the transmission belt 48 is suitably prevented.

Further, according to the present embodiment, when the abnormality of the forward clutch 38 or the reverse brake 40 is determined by the friction engagement device abnormality determining means 100 (SA3), the clamping force increasing means 104 (SA4). Since the squeezing force controlled by the squeezing force control means 92 is increased, the forward clutch disposed in series with the belt-type continuously variable transmission 18 in the power transmission path between the engine 12 and the drive wheels 24L and 24R. Even if an abnormality occurs in 38 and its transmission torque becomes excessive and its torque limiter function is impaired, slippage of the transmission belt 48 is suitably prevented.

Further, according to this embodiment, when the shift lever operation position detection abnormality determining means 102 (SA5) determines that the shift lever operation position sensor 68 is abnormal, the squeezing pressure increasing means 104 (SA6) uses the same. Since the squeezing pressure controlled by the squeezing force control means 92 is increased, even if an abnormality occurs in the detection of the switching position of the shift lever 67 and the squeezing pressure controlled corresponding to the actual switching position is reduced. The sliding force of the transmission belt 48 is suitably prevented by the clamping force increased by the clamping force increasing means 104.

Further, according to this embodiment, clamping pressure control means 92, hydraulic oil temperature (lubricating oil temperature) T _{OI L} Friction, such as an engine 12 and the forward-reverse switching device 16 as temperature (frictional resistance) min In order to cope with the increase in the oil temperature, oil pressure correction means 94 for preventing the transmission belt 48 from slipping during deceleration traveling or the like by correcting the squeezing pressure against the transmission belt 48 as the hydraulic oil temperature T _OIL decreases.
The clamping pressure increasing means 104 increases the clamping pressure to a value corresponding to the lowest value T _OILmin of the operating oil temperature range. At times, the clamping pressure is corrected to a value on the side of the temperature range on which slippage of the power transmission member is least likely to occur, so that slippage of the transmission belt 48 is suitably prevented.

According to the present embodiment, the forward clutch 38 of the forward / reverse switching device 16 is connected to the engine 12 and the drive wheels 24.
L and 24R, which are arranged in series with the belt-type continuously variable transmission 18 in a power transmission path, and the forward clutch 38 or the reverse brake 40 is necessary for transmitting the output torque of the engine 12 and By controlling the clutch control means 90 to provide a sufficient transmission torque, the abnormal torque is applied to the belt-type continuously variable transmission 18 when the abnormal torque generated from the drive wheels 24L and 24R due to the rough road traveling is transmitted. Although it functions as a torque limiter for preventing transmission of the abnormal torque so that the abnormal torque is not transmitted to the forward clutch 38 or the reverse brake 4 due to malfunction of the clutch control means 90.
Even if the transmission is transmitted to the belt-type continuously variable transmission 18 without being absorbed by 0, the clamping force of the transmission belt 48 is increased.
Slippage of the transmission belt 48 caused by the abnormal torque is suitably prevented.

According to this embodiment, the shift lever operation is performed.
The working position detection abnormality determining means 102 determines that the shift lever 67
From the non-traveling range (for example, N range) to the traveling range (
Despite being operated to D range)
The output of the lever operation position sensor 68 indicates the non-traveling range.
Means to determine when the pressure is
104 is a clamping force controlled by the clamping force control means 92
From the squeezing pressure and the non-running range
The difference between the pinching pressure and the value above
Therefore, the clamping pressure increasing means 104
The clamping pressure in the traveling range and the clamping pressure in the non-traveling range
Pressure difference or greater increase P _UPIncreased
Of the shift lever operation position sensor 68
Of the transmission belt 48 caused by the
You.

While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the above embodiment, a pair of variable pulleys 42, 4 around which a transmission belt 48 is wound
Although the so-called belt-type continuously variable transmission 18 having the gear 6 is used, the present invention can be applied to other continuously variable transmissions such as a toroidal-type continuously variable transmission. In short, the gear ratio is stepless by changing the contact position of the power transmission member, which is interposed and pressed between the input side rotating body and the output side rotating body, with the input side rotating body and the output side rotating body. What is necessary is just a continuously variable transmission that can be changed to.

In the above-described embodiment, the relationship used in the oil temperature correction means 94 may be a relationship in which the increase value P _UP changes stepwise as the oil temperature T _OIL increases.

In the embodiment shown in FIG.
1 and SA2, SA3 and SA4, SA5 and S
Only one of A6 may be performed.

Although the embodiments of the present invention have been described in detail with reference to the drawings, this is merely an embodiment,
The present invention can be implemented in various modified and improved aspects based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of a vehicle drive device to which a control device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a main part of a hydraulic control circuit for controlling a belt-type continuously variable transmission in the vehicle power transmission device shown in FIG. 1, showing a portion related to belt tension control.

FIG. 3 is a diagram illustrating a main part of a hydraulic control circuit for controlling a belt-type continuously variable transmission in the vehicle power transmission device in FIG. 1, illustrating a portion related to speed ratio control.

FIG. 4 is a diagram simply showing an electric configuration of the control device of the embodiment of FIG. 1;

FIG. 5 is a diagram showing a relationship stored in advance used for determining a target rotation speed in a gear ratio control executed by the electronic control device of FIG. 4;

FIG. 6 is a functional block diagram illustrating a main part of a control function of the electronic control device of FIG. 4;

7 is a flowchart illustrating a main part of a control operation of the electronic control device of FIG. 6, and is a diagram illustrating a routine corresponding to a clamping force control unit and the like.

[Explanation of symbols]

 12: Engine (motor) 18: Belt-type continuously variable transmission (continuously variable transmission) 24L, 24R: Drive wheels 38: Forward clutch (friction engagement device) 40: Reverse brake (friction engagement device) 48: Transmission belt (Power transmission member) 66: Electronic control device 67: Shift lever 98: Oil temperature sensor abnormality determination means 100: Friction engagement device abnormality determination means 102: Shift lever operation position detection abnormality determination means 104: Nipping pressure increasing means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // F16H 59:08 F16H 59:08 59:24 59:24 59:40 59:40 59:42 59: 42 59:44 59:44 59:70 59:70 63:06 63:06 (72) Inventor Daisuke Inoue 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Katsumi Kawano Toyota, Aichi Prefecture 1 Toyota Town, Toyota Motor Corporation (72) Inventor Koji Taniguchi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F term (reference) 3J028 EA30 EB10 EB16 EB35 EB37 EB43 EB62 FB06 FC13 FC23 FC32 FC64 GA01 3J050 AA02 AB07 BA03 BA18 BB12 CE09 DA01 3J552 MA07 MA08 MA09 MA12 MA26 NA01 NB01 PA12 PA13 PA63 PB03 PB05 SA36 TA01 TB03 VA02W VA18Z VA32Z VA37Z VA48W VA62W VA74Z VB01Z VC01Z VC02Z VC03Z VD02Z

Claims (4)

[Claims] In a continuously variable transmission for a vehicle that transmits power through friction between the power transmission member and a power transmission member for transmitting power, a clamping force applied to the power transmission member is required and sufficiently controlled, A control device for a continuously variable transmission for a vehicle, comprising: a squeezing force control unit configured to correct a squeezing force applied to the power transmission member based on a hydraulic oil temperature of the continuously variable transmission detected by an oil temperature sensor. Oil temperature sensor abnormality determining means for determining whether or not the oil temperature sensor is abnormal; and controlling the clamping pressure control means when the oil temperature sensor abnormality is determined by the oil temperature sensor abnormality determining means. And a squeezing pressure increasing means for increasing the squeezing pressure. 2. A continuously variable vehicle that is arranged in series with a friction engagement device between a prime mover and a drive wheel and transmits power through friction between a power transmission member for transmitting power. In a transmission, a control device for a continuously variable transmission for a vehicle comprising a clamping force control means for controlling a clamping force on the power transmission member in a necessary and sufficient manner, wherein the engagement and disengagement operations of the friction engagement device are performed. Frictional engagement device abnormality determination means for determining whether or not an abnormality is present; and when the frictional engagement device abnormality determination means determines that the frictional engagement device is abnormal, the frictional engagement device is controlled by clamping force control means. A control device for a continuously variable transmission for a vehicle, comprising: a squeezing pressure increasing means for increasing a squeezing pressure. 3. The control device for a continuously variable transmission for a vehicle according to claim 2, wherein the friction engagement device is a forward clutch or a reverse brake of a forward / reverse switching device. 4. A continuously variable transmission for a vehicle that transmits power through friction between the power transmission member and a power transmission member for transmitting power, wherein a clamping force on the power transmission member is controlled as necessary and sufficiently, and What is claimed is: 1. A control device for a continuously variable transmission for a vehicle, comprising a squeezing force control means for correcting the squeezing force according to a switching position by a shift lever, wherein a shift lever operation position sensor for detecting an operation position of the shift lever. Shift lever operation position detection abnormality determining means for determining whether or not the shift lever operation position sensor is abnormal, and when the shift lever operation position sensor abnormality is determined by the shift lever operation position detection abnormality determination means, clamping force control means Control means for increasing the clamping force controlled by the control device.