JPH07122463B2 - Electronically controlled continuously variable transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits an engine output of an automobile to a driven part by using a continuously variable transmission mechanism capable of continuously changing an input / output torque ratio.
The present invention relates to an electronically controlled continuously variable transmission in which an electronic control means for generating a control signal based on a detection signal obtained by detecting an engine load state or the like controls the continuously variable transmission mechanism.

[0002]

2. Description of the Related Art In an automobile, in order to efficiently transmit the output of the engine to the wheels which are driven bodies, a transmission mechanism is arranged between the engine and the wheels, and the output of the engine is transmitted through the transmission mechanism to the wheels. As this transmission mechanism, there is known a transmission mechanism that employs a continuously variable transmission mechanism that can continuously change the transmission ratio within a predetermined range.
Such a continuously variable transmission mechanism mounted on an automobile is adjusted by the vehicle speed or the engine speed and the operation of an accelerator adjusting means such as an accelerator pedal, as described in JP-A-55-76709. The gear ratio control is performed based on the throttle valve opening.

In such a case, normally, the gear ratio of the continuously variable transmission is such that the engine speed with respect to the throttle valve opening, and hence the input rotational speed of the continuously variable transmission, is uniquely determined. Controlled. That is, a predetermined engine speed is obtained for each throttle valve opening value,
Therefore, the gear ratio is controlled so that a predetermined engine output is obtained. For example, control is performed so that the relationship between the throttle valve opening Th and the transmission input shaft rotation speed Np of the continuously variable transmission mechanism follows the shift characteristics as shown in FIG. In the shift characteristics of FIG. 9, “dow”
The area labeled "n" is the downshift area,
The area displayed as "up" is an upshift area. In such control, the electronic control means for the continuously variable transmission is supplied with the detection signals from the throttle valve opening detection means and the input speed detection means of the continuously variable transmission, and the electronic control means responds to the respective detection signals. The control output is sent to the gear ratio adjusting unit of the continuously variable transmission mechanism to be performed.

[0004]

By the way, when a gear ratio control based on such a gear shift characteristic is being performed, a throttle signal system which detects a throttle valve opening and produces a detection output, or a continuously variable transmission mechanism. When an abnormality occurs in the input shaft rotation speed signal system that detects the input shaft rotation speed and generates a detection signal, a significant disadvantage occurs in the operation of the continuously variable transmission mechanism.
For example, if the detection signal cannot be obtained due to disconnection in the throttle signal system during normal traveling of an automobile,
The throttle valve opening is regarded as zero by the electronic control means, and the continuously variable transmission mechanism is controlled so as to perform a rapid shift-up according to the gear shift characteristic shown in FIG. The phenomenon of being shocked occurs. Further, when the input shaft rotation speed detection system is disconnected and the detection signal cannot be obtained, the electronic control means regards the input shaft rotation speed of the continuously variable transmission mechanism as zero, and the continuously variable transmission mechanism is operated as shown in FIG. In accordance with the gear shift characteristic shown in (1), the control is performed so as to perform the abrupt shift down, so that the vehicle may be in a state in which the strong engine brake is applied and the engine may overrun.

Therefore, conventionally, when the abnormality of the detection system as described above occurs, countermeasures such as fixing the gear ratio of the continuously variable transmission mechanism to a constant value or shifting to the upshift side have been taken. In the former method, the gear ratio control corresponding to the fluctuation of the engine load is not performed, so that the engine is overloaded and the engine sound becomes abnormally high, and in the latter method, When the vehicle restarts, there is a problem such as insufficient driving force or burning of the clutch.

As described above, when some abnormality occurs in the throttle signal system for detecting the throttle valve opening or the input shaft rotational speed signal system for detecting the input shaft rotational speed of the continuously variable transmission mechanism. The control signal sent from the electronic control means to the gear ratio adjusting means becomes abnormal, and proper control of the continuously variable transmission mechanism cannot be expected.

In view of the above point, the present invention supplies a control signal to the gear ratio adjusting means for controlling the gear ratio of the continuously variable transmission mechanism in order to control the continuously variable transmission mechanism so as to follow a predetermined gear shift characteristic. If any abnormality occurs in the necessary detection signal that should be input to the electronic control means, the gear ratio changing control for the continuously variable transmission mechanism can be performed irrespective of the abnormality detection signal. As a result, it is an object of the present invention to provide an electronically controlled continuously variable transmission that enables basic running of an automobile without causing significant inconvenience.

[0008]

In order to achieve the above object, an electronically controlled continuously variable transmission according to the present invention is connected to an engine and is capable of continuously changing a gear ratio. A gear ratio adjusting means for changing the gear ratio of the continuously variable transmission mechanism; a detecting means for detecting a load state of the engine to generate a first detection signal; and an engine speed or a speed related thereto. The electronic control means comprises a detection means for detecting and generating a second detection signal, and an electronic control means for the gear ratio adjusting means.
And whether the second detection signal is abnormal or not, and if both detection signals are not abnormal, the shift down range is determined based on both the engine load and the engine speed or the related speed. Based on the first shift control characteristic in which the upshift range is set ,
When the gear ratio changing control is performed and one of the first and second detection signals is abnormal, the one that has become abnormal
The change ratio change control according to the detection signal of
And a second shift control characteristic in which a shift-down region and a shift-up region are set with a predetermined value of the engine load or the engine speed or a speed related thereto as a boundary in accordance with the other of the second detection signals. The control signal is sent to the gear ratio adjusting means in order to perform the gear ratio changing control of the continuously variable transmission mechanism.

[0009]

In the electronically controlled continuously variable transmission according to the present invention constructed as above, the detecting means itself for detecting the load state of the engine or the means for transmitting the first detection signal generated by the detecting means, Further, both the detection means itself for detecting the engine speed or the rotation speed related thereto or the means for transmitting the second detection signal generated by the detection means are normal, and both the first and second detection signals are If not abnormal, the electronic control means and the gear ratio adjusting means respond to both the first and second detection signals, and based on both the engine load and the engine rotational speed or the rotational speed related thereto, the downshift region. The gear ratio change control of the continuously variable transmission mechanism is performed based on the first gear shift control characteristic in which the upshift region and the upshift region are set. On the other hand, the detection means itself for detecting the load state of the engine or the means for transmitting the first detection signal generated by the detection means, and the detection means for detecting the engine speed or the speed related thereto or the generation means thereof. If one of the means for transmitting the second detection signal is abnormal and one of the first and second detection signals is abnormal, the electronic control means and the gear ratio adjusting means One of the abnormal detection signals
The gear ratio change control according to the signal is prohibited, and the predetermined value of the engine load or the engine speed or its related speed is set as a boundary according to the other of the first and second detection signals that are not abnormal. As a result, the gear ratio change control of the continuously variable transmission mechanism is performed in accordance with the second shift control characteristic in which the shift down region and the shift up region are set.

Therefore, according to the electronically controlled continuously variable transmission according to the present invention, the gear ratio change control of the continuously variable transmission is performed by the first detecting means for detecting the load state of the engine.
Of the first detection signal and the second detection signal when performing the detection based on the second detection signal from the detection means for detecting the engine rotation speed or the rotation speed related thereto. When the occurrence of the occurrence occurs, the gear ratio that can be practically used according to the engine load or the engine speed according to the other of the first detection signal and the second detection signal.
The change control state will be obtained. Therefore, the vehicle equipped with the electronically controlled continuously variable transmission according to the present invention is not accompanied by a significant inconvenience such as a sudden engine braking condition or an engine overrun condition, even when the above-mentioned abnormality occurs. You will be able to perform basic driving.

[0011]

FIG. 2 shows an outline of a drive control unit of an automobile to which an example of an electronically controlled continuously variable transmission according to the present invention is applied. In FIG. 2, a throttle valve 3 for controlling fuel supply is arranged in an intake passage 2 of a reciprocating piston type engine 1. The throttle valve 3 is driven to open and close by a throttle actuator 4 and its opening degree is a throttle. The position sensor 5 detects this. The end portion of the intake passage 2 on the downstream side of the throttle valve 3 serves as branch passages 2a, 2b, 2c, and 2d so as to communicate with each cylinder.
A fuel injection valve is provided at 2d.

An output shaft 6 of the engine 1 is connected to a continuously variable transmission 9 via a clutch 7 and a switching gear train 8, and an output shaft 10 of the continuously variable transmission 9 is connected to driving wheels 12 via a differential gear 11. It is connected. Also, engine 1
Engine rotation speed detection sensor 13 for detecting the rotation speed of the output shaft 6 of the clutch, clutch output shaft rotation speed detection sensor 15 for detecting the rotation speed of the output shaft 14 of the clutch 7, rotation speed of the input shaft 16 of the continuously variable transmission 9 The transmission input shaft speed detection sensor 17 for detecting the rotation speed, the rotation speed of the output shaft 10 of the continuously variable transmission 9,
Therefore, the transmission output shaft rotation speed detection sensors 18 that detect the vehicle speed are installed at predetermined positions. And
Throttle position signal P ₅ from the throttle position sensor 5 described above, the engine output shaft speed signal P ₂ from the engine speed detection sensor 13 described above, the clutch output shaft speed signal P from the clutch output shaft rotational speed sensor 15 ₄ , the transmission input shaft rotation speed signal P ₆ from the transmission input shaft rotation speed detection sensor 17, and the transmission output shaft rotation speed signal P ₈ from the transmission output shaft rotation speed detection sensor 18,
Interface unit 19 and CPU (central processing unit)
20 and the memory 21 are input to the electronic control circuit unit 22 which is configured by main components.

Further, an accelerator operated by a driver
The amount of depression of the pedal 23, that is, the accelerator opening is the accelerator opening.
Detected by the degree sensor 24, the brake pedal 25
The depression state of the vehicle is detected by the brake operation detection sensor 26.
Further, the shift position of the shift lever 27 is changed to the shift lever.
-Access is detected by the position detection sensor 28.
Accelerator opening signal P according to the amount of depression of the pedal 23₁，
Obtained by stepping on the brake pedal 25
Brake operation signal P₃And the position of the shift lever 27
Shift lever position signal P according to₇But each,
It is input to the electronic control circuit unit 22. And electronic control times
Signals obtained from the sensors and input from the road section 22
P₁~ P₈Based on the control signals S₁, S₂, S₃，
S_Four, S _FiveAnd S₆Is output.

FIG. 1 is a schematic view of an example of an electronically controlled continuously variable transmission according to the present invention, which includes the clutch 7, the switching gear train 8, the continuously variable transmission 9 and the electronic control circuit section 22 described above. Show. Here, of the various control signals S _{1 to} S ₆ from the electronic control circuit section 22, the clutch control signal S ₁ is received and the A solenoid (A SOL) of the clutch control valve 29 is received.
30 receives the clutch control signal S _2, and the B solenoid (B SOL) 31 of the clutch control valve 29 is
It is excited and the supply state of the operating pressure oil to the clutch 7 is controlled. Further, the shift control signal C solenoid (C SOL) 33 of S ₃ receiving and transmission control valve 32, D solenoid (D shift control valve 32 receives the shift control signal S ₄
SOL) 34 are respectively excited, the supply state of the operating pressure oil to the continuously variable transmission 9 is controlled, and the gear ratio thereof is controlled.

Further, the shift control valve 43 controlled by switching the shift lever 27 to each of the forward D, neutral N and reverse R shift positions by the manual operation of the driver, the clutch control valve 29 and the shift control described above. The valve 32 includes a filter 3 from the oil tank.
The working pressure oil is supplied through the hydraulic pump 5 and the hydraulic pump 36.
The line pressure supplied from the hydraulic pump 36 is adjusted by the pressure reducing valve 37 that receives the line pressure control signal S ₅ from the electronic control circuit unit 22.

Further, in response to the throttle control signal S ₆ , the throttle actuator 4 is actuated, whereby
The opening of the throttle valve 3 is adjusted. The continuously variable transmission controlled by supplying the hydraulic oil in this manner is configured so as to transmit the output of the engine 1 to the drive wheels 12 and control related thereto as described below. ing.

That is, the rotation of the output shaft 6 of the engine 1 is first intermittently press-contacted to the flywheel 38 provided at the end of the output shaft 6 and is rotated coaxially with the output shaft 6. Be transmitted to. The clutch 7 has a friction plate 39 that is in pressure contact with the flywheel 38, and a diaphragm-shaped clutch spring 40 to which a pressing plate that presses the friction plate 39 is fixed, and the clutch control signal S ₁ is a clutch control valve. When it is delivered to the A solenoid 29 of No. 29, the A solenoid 30 is excited to be in the ON state, whereby the working pressure oil is supplied to the clutch actuator 41 from the opening port, inside which the piston resists the elastic force of the spring. Then, the lever 42 is rotated counterclockwise. As a result, the clutch spring 40 in the open state is moved to the closed state, presses the friction plate 39, and the clutch 7 is brought into the connected state. As a result, the rotation of the output shaft 6 of the engine 1 is transmitted to the output side of the clutch 7.

When the clutch control signal S ₂ is sent to the B solenoid 31 of the clutch control valve 29, the B solenoid 31 is excited and turned on, and the working pressure oil is discharged from the clutch actuator 41, and The piston is returned inside by the elastic force of the spring, and the clutch spring 40 is opened. As a result, the pressed state of the friction plate 39 against the flywheel 38 is released, and the clutch 7 is disengaged. In this state, the rotation of the output shaft 6 of the engine 1 is prevented from rotating by the clutch 7
Is not transmitted to the output side of.

Further, when neither of the clutch control signals S ₁ and S ₂ is sent to the A solenoid 30 and the B solenoid 31 of the clutch control valve 29,
The opening port of the clutch control valve 29 is closed, and the piston in the clutch actuator 41 is maintained in the state immediately before that. Therefore, the flywheel 38 of the friction plate 39 is maintained.
The pressed state with respect to is maintained. On the output side of the clutch 7 which operates in this way, to the input shaft 16 of the continuously variable transmission 9,
Forward D, neutral N and reverse R of shift lever 27
A switching gear train 8 is provided so that the rotation of the output shaft 6 of the engine 1 is transmitted according to each shift position.

In the switching gear train 8, when the shift lever 27 is set to the forward drive D position, the piston of the shift actuator 44 moves in the D direction in the figure, and the forward drive gear fixed to the output shaft 14 of the clutch 7. 45 to the input shaft 1 of the continuously variable transmission 9
6 engages with the gear 46 to rotate the input shaft 16 of the continuously variable transmission 9 in the direction opposite to the output shaft 14 of the clutch 7. On the other hand, when the shift lever 27 is set to the reverse R position, the piston of the shift actuator 44 moves in the R direction in the figure, and the gear 47 provided on the input shaft 16 of the continuously variable transmission 9 causes the output shaft of the clutch 7 to move. The input shaft 16 of the continuously variable transmission 9 is engaged with the idle gear 49 which is engaged with the reverse gear 48 fixed to the gear 14, so as to move the input shaft 16 in the direction opposite to that of the forward drive D, that is, the clutch. 7 is rotated in the same direction as the output shaft 14. Further, when the shift lever 27 is set to the neutral N position, the piston of the shift actuator 44 is held in the center of the cylinder, and the rotation of the output shaft 14 of the clutch 7 is not transmitted to the input shaft 16 of the continuously variable transmission 9. Is done like this.

The continuously variable transmission 9 to which the rotation of the output shaft 14 of the clutch 7 is transmitted is an input shaft 16 that rotates coaxially with the output shaft of the switching gear train 8, and is rotationally driven integrally with the input shaft 16. And a driven pulley 52 to which the rotation of the driving pulley 50 is transmitted via a V-belt 51.
It has the driven pulley 52 and the output shaft 10 which rotates integrally. The drive pulley 50 has a movable conical plate 50a and a fixed conical plate 50b.
The a and the fixed conical plate 50b form a V-shaped pulley groove with their conical surfaces facing each other. Movable conical plate 5
0a is provided with a cylinder chamber 50c behind it, and is slidable in the axial direction so as to come close to or away from the fixed conical plate 50b depending on the supply state of the working pressure oil to the cylinder chamber 50c. The fixed conical plate 50b is fixed to the input shaft 16. On the other hand, the driven pulley 52 also has the same structure as the above-mentioned drive pulley 50, and the movable conical plate 52
The V-shaped pulley groove is formed by a and the fixed conical plate 52b, and the movable conical plate 52a comes close to the fixed conical plate 52b due to the supply state of the working pressure oil to the cylinder chamber 52c provided behind it. Thus, the fixed conical disc 52b is fixed to the output shaft 10.

These drive pulley 50 and driven pulley 52
The V-belt 51 is stretched around the respective pulley grooves formed in the drive pulley 50, whereby the rotation of the drive pulley 50 is prevented.
2 is transmitted. When the rotation of the drive pulley 50 is transmitted to the driven pulley 52, it is determined by the radius of rotation of the V belt on the drive pulley 50 side, which is determined by the width of the pulley groove of the drive pulley 50, and the width of the pulley groove of the driven pulley 52. By changing the radius of rotation of the V belt on the driven pulley 52 side, the rotation ratio between the drive pulley 50 and the driven pulley 52 can be changed.

Drive pulley 50 and driven pulley 52, respectively
The width of the pulley groove of each of the movable conical plates 50a and
52a is slid in the axial direction.
In order to make the movable conical plates 50a and 52a slide,
A speed control valve 32 is provided. This shift control valve
The shift control signal S from the electronic control circuit unit 22 ₃
C solenoid 33 that is turned on and off by the
Issue S_FourAnd a D solenoid 34 that is turned on and off by
And the C solenoid 33 is turned on.
First, the operating pressure oil is applied to the cylinder chamber 50c of the drive pulley 50.
And the cylinder chamber 52c of the driven pulley 52
From the hydraulic oil, and the D solenoid 34 is turned on.
Cylinder chamber of the driven pulley 52
52c to supply operating pressure oil and to drive the drive pulley 50.
The working pressure oil is removed from the cylinder chamber 50c. Also, C
Both the Renoid 33 and the D solenoid 34 are off.
When driven, the drive pulley 50 and the driven pulley 52
Supply of operating pressure oil to the respective cylinder chambers 50c and 52c
And the exclusion is stopped.

The shift control valve 3 having the above-mentioned function.
2, when the C solenoid 33 is turned on by the shift control signal S ₃ , the working pressure oil from the hydraulic pump 36 is supplied from the supply port to the cylinder chamber 5 of the drive pulley 50.
0c, whereby the movable conical disc 50a is moved in the direction of approaching the fixed conical disc 50b, and the width of the pulley groove formed with the fixed conical disc 50b is reduced.
The radius of rotation of the belt 51 on the drive pulley 50 side increases. At the same time, the working pressure oil filled in the cylinder chamber 52c of the driven pulley 52 is removed from the discharge port, whereby the movable conical plate 52a is moved to the fixed conical plate 5c.
2b is moved away from the fixed conical plate 5
The width of the pulley groove formed by 2b and the V-belt 5 is increased.
The radius of gyration on the driven pulley 52 side of No. 1 is reduced.
Therefore, the gear ratio in the continuously variable transmission 9 is reduced.

On the other hand, the D solenoid 34 causes the shift control signal S
_{When the} switch is turned on by _4, the operating pressure oil from the hydraulic pump 36 is supplied from the supply port to the cylinder chamber 52c of the driven pulley 52 and from the cylinder chamber 50c of the drive pulley 50, contrary to the above case. The operating pressure oil is removed, the width of the pulley groove of the drive pulley 50 is expanded, and V
The radius of rotation of the belt 51 on the drive pulley 50 side is reduced, and at the same time, the width of the pulley groove of the driven pulley 52 is reduced, so that the radius of rotation of the V belt 51 on the driven pulley 52 side is enlarged. Therefore, in this case, the gear ratio in the continuously variable transmission 9 is increased.

Further, when neither of the shift control signals S ₃ and S ₄ is sent to the C solenoid 33 and the D solenoid 34 and each solenoid is turned off, the drive pulley 50 and the driven pulley 50 are driven. The width of each pulley groove of 52 is maintained at the width immediately before that, so that the respective turning radii of the V belt 51 on the drive pulley 50 side and the driven pulley 52 side are maintained, and the speed change in the continuously variable transmission 9 is performed. The ratio is maintained just before the C solenoid 33 and the D solenoid 34 are turned off.

In an example of the electronically controlled continuously variable transmission according to the present invention having the above-mentioned configuration, in the electronic control circuit section 22, the accelerator opening α representing the load state of the engine is the accelerator opening α. The input shaft rotational speed Np of the continuously variable transmission 9 representing the rotational speed of the engine 1 is detected by the transmission input shaft rotational speed detection sensor 17 while being detected from the accelerator opening signal P ₁ obtained by the detection sensor 24. is detected from the transmission input shaft speed signal P _6, when the accelerator opening signal P ₁ and the transmission input shaft speed signal P ₆ is normal, according to the input shaft rotational speed Np that these accelerator opening α In FIG. 3, the accelerator opening degree as represented by a shift characteristic diagram (hereinafter referred to as X map) is shown in which the vertical axis represents the transmission input shaft rotation speed Np and the horizontal axis represents the accelerator opening α. α The gear ratio change control of the continuously variable transmission 9 is performed in accordance with the gear shift control characteristics in which the shift down region down and the shift up region up are set based on both the transmission input shaft speed Np and the transmission input shaft speed Np. The shift control signals S ₃ and S ₄ are sent to the C solenoid 33 and the D solenoid 34 of the shift control valve 32 which is the shift adjusting means. The gear ratio changing control in such a case is performed at a normal gear ratio changing speed h ', whereby the input shaft speed Np of the continuously variable transmission 9 and thus, for each value of the accelerator opening α, The rotation speed of the engine 1 is set to a predetermined value.

On the other hand, when the accelerator opening degree signal P ₁ obtained by the accelerator opening degree detecting sensor 24 becomes abnormal due to, for example, a disconnection in the accelerator opening degree detecting sensor 24, it is detected by the electronic control circuit section. 22 and in accordance with only the input shaft rotational speed Np detected from the transmission input shaft rotational speed signal P ₆ regardless of the accelerator opening α at that time. A shift-down region down and a shift-up region up are set with a predetermined value of the transmission input shaft rotational speed Np as a boundary, which is represented by a shift characteristic diagram (hereinafter referred to as Y map) similarly shown in FIG. that shift control signals S ₃ and S ₄ ratio changing control is to be performed in the continuously variable transmission 9 which conforms to the shift control characteristic, C solenoids 33 and D solenoid shift control valve 32 4 is sent to. Then, the gear ratio changing control in such a case is performed at a gear ratio changing speed h'which is smaller than usual, whereby the downshift control is performed until the transmission input shaft rotational speed Np reaches a predetermined value. After reaching the predetermined value, the upshift control is performed.

Further, the transmission input shaft rotation speed detection sensor 1
If the transmission input shaft rotation speed signal P ₆ obtained by 7 becomes abnormal due to, for example, disconnection in the transmission input shaft rotation speed detection sensor 17, it is detected by the electronic control circuit unit 22. The speed change shown in FIG. 5 in the same manner as the speed change characteristic diagram of FIG. 3 in accordance with only the accelerator opening α detected from the accelerator opening signal P ₁ regardless of the input shaft speed Np at that time. A continuously variable shift based on a shift control characteristic in which a shift down region down and a shift up region up are set with a predetermined value of the accelerator opening α as a boundary, which is represented by a characteristic diagram (hereinafter referred to as a Z map). Gear change control signals S ₃ and S ₄ for performing the gear ratio change control of the machine 9 are sent to the C solenoid 33 and the D solenoid 34 of the gear change control valve 32. Then, the gear ratio changing control at that time is also performed at a gear ratio changing speed h'which is smaller than usual, whereby the shift down control is performed until the accelerator opening α reaches a predetermined value, and After reaching the value of, the upshift control is performed.

The predetermined value of the transmission input shaft speed Np in the Y map shown in FIG. 4 and the predetermined value of the accelerator opening α in the Z map shown in FIG. 5 are, for example, as shown in FIG. On the characteristic curve in the X map shown in FIG. 5, the middle of the period from the value of the transmission input shaft rotational speed Np of the portion indicated by a to the value of the transmission input shaft rotational speed Np of the portion indicated by b. The value of the transmission input shaft speed Np and the value of the accelerator opening α at point c can be selected respectively.

A series of control of the gear ratio of the continuously variable transmission 9 as described above is performed based on the operation of the CPU 20 of the electronic control circuit section 22. An example of the program executed by the CPU 20 will be described with reference to FIG. , And will be described with reference to the flowcharts of FIGS.

First, as shown in the flow chart of FIG. 6, after the start, each part is initialized in step 60, then in step 61, the program for clutch control is first executed, and then step 6
In step 2, the program for gear ratio change control is executed, and the process returns to step 61.

An example of the program for clutch control executed in the above step 61 is as shown in the flowchart of FIG. Here, after the start, in step 70, it is determined whether or not the shift lever 27 is in the neutral range (N range) position, and the shift lever 27 is in the neutral range position. If it is in the state, the vehicle speed flag FV is reset in step 71, and in the following step 72, the clutch control signal S ₂ is sent to the B solenoid 31 of the clutch control valve 29.
To turn on the B solenoid 31 and turn off the A solenoid 30. As a result, the clutch 7 is turned off.

[0034] In step 70, the shift lever 27
Is not in the neutral range position
If it is determined that the
If the vehicle speed V is higher than the preset predetermined vehicle speed Va
Determine if there is. Here, the vehicle speed Va is the engine
The vehicle speed is set so that there is a high risk of stopping the vehicle.
When it is determined that the speed V is higher than the vehicle speed Va
Sets the vehicle speed flag FV in the following step 74.
And proceed to step 75.

In step 75, it is judged whether the change amount Ne 'of the engine output shaft speed Ne is positive or negative. If the change amount Ne' of the engine output shaft speed Ne is positive, in step 76. , It is determined whether the engine output shaft rotational speed Ne is higher than the clutch output shaft rotational speed Nc.
Engine output shaft speed Ne is clutch output shaft speed Nc
When it is determined that the value is larger, the clutch control signal S ₁ is sent to the A solenoid 30 of the clutch control valve 29 to turn on the A solenoid 30 and turn off the B solenoid 31 in step 77. To do. As a result, the friction plate 39 of the clutch 7 is brought into a state of pressing the flywheel 38, and the transmission torque capacity of the clutch 7 is gradually increased.

On the other hand, if it is determined in step 75 that the change Ne 'of the engine output shaft revolution speed Ne is negative, the engine output shaft revolution speed Ne is determined from the clutch output shaft revolution speed Nc in step 78. If the engine output shaft speed Ne is smaller than the clutch output shaft speed Nc, the routine proceeds to step 77.
As a result, the transmission torque capacity of the clutch 7 is gradually increased. In step 78, the engine output shaft speed N
If it is determined that e is not less than the clutch output shaft rotational speed Nc, and if it is determined in step 76 that the engine output shaft rotational speed Ne is not greater than the clutch output shaft rotational speed Nc, then in step 79. , The clutch control signals S ₁ and S ₂ are prevented from being sent out, whereby the pressing state of the friction plate 39 of the clutch 7 against the flywheel 38 is maintained as it is, and therefore the transmission torque capacity of the clutch 7 is reduced. It is maintained as it is.

If it is determined in step 73 that the vehicle speed V at that time is not higher than the vehicle speed Va,
In step 80, it is determined whether the accelerator pedal 23 is in the on state, that is, whether the accelerator pedal 23 is stepped on. If it is determined that the accelerator pedal 23 is in the on state, the process proceeds to step 75 and Each step is performed as described above.

On the other hand, when it is determined in step 80 that the accelerator pedal 23 is not in the on state, it is determined in step 81 whether the vehicle speed flag FV is in the set state, and the vehicle speed flag FV is not in the set state. If the vehicle speed flag FV is in the set state, it is determined in step 82 whether the brake pedal 25 is on, that is, whether the brake pedal 25 is depressed, When it is determined that the brake pedal 25 is in the on state, the process proceeds to step 83.

Then, at step 83, it is judged if the engine output shaft rotational speed Ne is a predetermined value, for example, 1500 rpm or less. Where the engine output shaft speed
1500rpm is when the brake pedal 25 is on,
If the engine speed is such that the engine may stop, and the engine output shaft speed Ne is not less than 1500 rpm, the process proceeds to step 75 and the following steps are performed as described above. And the engine output shaft speed Ne
If is less than 1500 rpm, proceed to step 71,
The following steps are performed as described above.

If the result of determination in step 82 is that the brake pedal 25 is not in the on state, it is determined in step 84 whether the engine output shaft speed Ne is a predetermined value, for example, 1000 rpm or less. To judge. Here, the engine output shaft rotational speed 1000 rpm is the rotational speed at which the engine may be stopped when the brake pedal 25 is in the off state. If the engine output shaft rotational speed Ne is not less than 1000 rpm, step 75 Go to
The following steps are performed as described above. on the other hand,
When the engine output shaft speed Ne is 1000 rpm or less, the process proceeds to step 71, and the following steps are performed as described above.

Next, an example of the program for gear ratio change control executed in step 62 of the program shown in FIG. 6 is as shown in the flowchart of FIG. In the flowchart of FIG. 8, after the start, in step 101, the accelerator opening α is read based on the accelerator opening signal P ₁ obtained from the accelerator opening detection sensor 24, and in the next step 102, the accelerator opening α is read. It is determined whether the detection sensor 24 is out of order. When it is determined in step 102 that the accelerator opening detection sensor 24 has not failed, in step 103 the stepless transmission is performed based on the transmission input shaft rotation speed signal P ₆ obtained from the transmission input shaft rotation speed detection sensor 17. The input shaft rotational speed Np of the transmission 9 is read, and in the next step 104, it is determined whether or not the transmission input shaft rotational speed detection sensor 17 is out of order.

If it is determined in step 104 that the transmission input shaft rotation speed detection sensor 17 is not in failure, that is, neither the accelerator opening detection sensor 24 nor the transmission input shaft rotation speed detection sensor 17 is in failure. In this case, in step 105, the setting for performing the normal gear ratio change control based on the gear shift control characteristic represented by the X map is performed according to the accelerator opening α and the transmission input shaft rotation speed Np. In step 106, when the gear ratio change control based on the gear shift control characteristic represented by the X map is performed, the gear ratio change speed h'is set to be normal. Then, step 107
In order to perform the gear ratio change control based on the gear shift control characteristic represented by the X map with the gear ratio changing speed h ′ set in step 106, the gear shift control signals S ₃ and S ₄ are provided to the gear shift control valve 32. C for upshift control and downshift control
It is sent to the solenoid 33 and the D solenoid 34.

If it is determined in step 102 that the accelerator opening detection sensor 24 is out of order, the process proceeds from step 102 to step 108, and in step 108 it is obtained based on the accelerator opening signal P _1. Instead of using the accelerator opening α, a shift control characteristic represented by a Y map that is predetermined in anticipation of a failure of the accelerator opening detection sensor 24 according to the input shaft speed Np of the continuously variable transmission 9 is obtained. The setting for performing the compliant gear ratio change control is made, and in the next step 109, Y
When the gear ratio changing control based on the gear shift control characteristic represented by the map is performed, the gear ratio changing speed h'is set to be smaller than usual. Then, in step 107, the speed change control signals S ₃ and S ₄ are changed in order to perform the speed change ratio changing control based on the speed change control characteristic represented by the Y map with the speed change ratio changing speed h ′ set in step 109. It is sent to the C solenoid 33 and the D solenoid 34 for the shift up control and the shift down control of the valve 32.

Further, when the accelerator opening detection sensor 24 is operating normally, but it is determined in step 104 that the transmission input shaft rotation speed detection sensor 17 is out of order, steps 104 to 110 are executed. Go to
In step 110, the transmission input shaft speed signal P ₆
The input shaft rotational speed detection sensor 17 for the transmission is used according to the accelerator opening α without using the input shaft rotational speed Np obtained based on
In the next step 111, the setting is made to perform the gear ratio change control in accordance with the shift control characteristic represented by the predetermined Z map in anticipation of the case where the Z map is set. When the gear ratio changing control based on the represented gear shift control characteristic is performed, the gear ratio changing speed h'is set to be smaller than usual. Then, in step 107, the speed change control signals S ₃ and S ₄ are changed in order to perform the speed change ratio changing control based on the speed change control characteristic represented by the Z map with the speed change ratio changing speed h ′ set in step 111. It is sent to the C solenoid 33 and the D solenoid 34 for the shift up control and the shift down control of the valve 32.

As described above, in step 107, the shift control signals S ₃ and S ₄ are sent to the C solenoid 33 and the D solenoid 34 provided in the shift control valve 32.
The programs for the gear ratio change control are terminated by sending the respective data and performing the gear ratio change control of the continuously variable transmission 9,
Then, it returns to step 61 which performs clutch control.

[0046]

As is apparent from the above description, in the electronically controlled continuously variable transmission according to the present invention, the gear ratio in the continuously variable transmission mechanism for transmitting the output of the engine to the wheels which are the driven parts is improved. Under the control by the electronic control means based on the signal according to the engine load and the signal according to the engine speed, both the signal according to the engine load and the signal according to the engine speed are If it is not abnormal, the shift-down region and the shift-up region are determined based on both the engine load and the engine speed or the related engine speed according to both the signal according to the engine load and the signal according to the engine speed. There is performed the speed ratio change control of the continuously variable transmission mechanism that conforms to the shift control characteristics set against it, the signal and the engine speed corresponding to the engine load If one of the corresponding signals becomes abnormal, the engine load or the engine speed or the rotation related to the engine load or the engine speed is changed according to the other one of the signals corresponding to the engine load and the signal corresponding to the engine speed. The gear ratio changing control of the continuously variable transmission mechanism is performed in accordance with the gear shift control characteristics in which the downshift region and the upshift region are set with a predetermined value of the number as a boundary.

As a result, according to the electronically controlled continuously variable transmission according to the present invention, the gear ratio change control of the continuously variable transmission mechanism can be performed.
When performing based on the signal corresponding to the engine load and the signal corresponding to the engine speed, if one of the signals corresponding to the engine load and the signal corresponding to the engine speed is abnormal, the engine load is According to the other of the signal corresponding to the engine speed and the signal corresponding to the engine speed, a gear ratio change control state that can withstand practical use according to the engine load or the engine speed is obtained. Therefore, the vehicle equipped with the electronically controlled continuously variable transmission according to the present invention is not accompanied by a significant inconvenience such as a sudden engine braking condition or an engine overrun condition, even when the above-mentioned abnormality occurs. It is supposed to be able to perform basic running.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an electronically controlled continuously variable transmission according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of an electronically controlled continuously variable transmission according to the present invention together with a drive control unit of a vehicle to which the electronically controlled continuously variable transmission is applied.

FIG. 3 is a characteristic diagram provided for explaining the operation of the example shown in FIG.

FIG. 4 is a characteristic diagram provided for explaining the operation of the example shown in FIG.

5 is a characteristic diagram provided for explaining the operation of the example shown in FIG. 1. FIG.

6 is a flowchart provided for explaining an operation program executed in the electronic control circuit unit used in the example shown in FIG.

7 is a flowchart provided for explaining an operation program executed in the electronic control circuit unit used in the example shown in FIG.

8 is a flowchart provided for explaining an operation program executed in the electronic control circuit unit used in the example shown in FIG.

FIG. 9 is a characteristic diagram provided for explaining general gear ratio control of a continuously variable transmission mechanism.

[Explanation of symbols]

 1 Engine 3 Throttle Valve 5 Throttle Position Sensor 7 Clutch 9 Continuously Variable Transmission 12 Drive Wheel 13 Engine Speed Detection Sensor 15 Clutch Output Shaft Speed Detection Sensor 17 Transmission Input Shaft Speed Detection Sensor 18 Transmission Output Shaft Speed Detection Sensor 22 Electronic control circuit section 23 Accelerator pedal 24 Accelerator opening detection sensor 26 Brake operation detection sensor 28 Shift lever position detection sensor 29 Clutch control valve 32 Shift control valve 50 Drive pulley 51 V belt 52 Driven pulley

Claims (3)

[Claims] 1. A continuously variable transmission mechanism connected to an engine, a gear ratio adjusting means for controlling a gear ratio of the continuously variable transmission mechanism, and a load state of the engine being detected to generate a first detection signal. Detecting means for detecting the engine speed or the engine speed related thereto to generate a second detection signal; and receiving the first and second detection signals to determine whether or not they are abnormal. If it is determined that the first and second detection signals are not abnormal, the downshift region and the upshift region are set based on both the engine load and the engine rotation speed or the rotation speed related thereto according to them. First done
In conformity with the shift control characteristics of the transmission ratio of the continuously variable transmission varying
Further control is performed, and if one of the first and second detection signals is abnormal, one of the detected abnormal signals is detected.
The gear ratio changing control according to the output signal is prohibited, and a predetermined value of the engine load or the engine speed or a speed related thereto is demarcated according to the other of the first and second detection signals. An electronic control for sending a control signal to the gear ratio adjusting means to perform a gear ratio change control of the continuously variable transmission mechanism based on a second gear shift control characteristic in which a shift down region and a shift up region are set as An electronically controlled continuously variable transmission comprising: 2. An electronic control means receives the first and second detection signals and judges whether they are abnormal or not, and if the first and second detection signals are not abnormal, responds to them. , In accordance with a first shift control characteristic in which a shift-down region and a shift-up region are set based on both the engine load and the engine rotation speed or the rotation speed related thereto,
Further, when the second detection signal is abnormal, a second shift control in which a downshift region and a upshift region are set with a predetermined value of the engine load as a boundary in accordance with the first detection signal. 2. The electronically controlled continuously variable transmission according to claim 1, wherein a control signal is sent to a gear ratio adjusting means to perform a gear ratio change control of the continuously variable transmission according to the characteristics. 3. An electronic control means receives the first and second detection signals and judges whether they are abnormal or not, and if the first and second detection signals are not abnormal, responds to them. , In accordance with a first shift control characteristic in which a shift-down region and a shift-up region are set based on both the engine load and the engine rotation speed or the rotation speed related thereto,
Further, when the first detection signal is abnormal, a shift-down region and a shift-up region are set with a predetermined value of the engine speed or the related engine speed as a boundary according to the second detection signal. 2. The electronically controlled continuously variable transmission according to claim 1, wherein a control signal is sent to the gear ratio adjusting means for performing the gear ratio change control of the continuously variable transmission mechanism according to the second gear shift control characteristic. Gearbox.