JP3304793B2 - Transmission control device for belt-type continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a belt-type continuously variable transmission.

[0002]

2. Description of the Related Art As a continuously variable transmission mounted on a vehicle,
A V-belt type is conventionally known, for example, Japanese Patent Application No. 8-105467 proposed by the present applicant.

[0003] This is provided with a pair of variable pulleys on an input side and an output side whose contact pulley width with a V-belt of a continuously variable transmission is variably controlled based on oil pressure, and drives a movable conical plate of the input pulley. The gear ratio is continuously changed by changing the hydraulic pressure supplied to the piston chamber. A shift control valve that adjusts the hydraulic pressure controls the line pressure and the communication amount of the drain as shown in FIG. And a spool valve.

In FIG. 9, a shift control valve 2 accommodates an axially displaceable spool 5 on the inner periphery of a housing, and the spool 5 is urged by a spring 9 from the left side in the figure, while being shown in FIG. The right end is urged by the solenoid 4, and the thrust of the solenoid 4 increases against the spring 9, so that the spool 5 moves to the left side in the figure to the position of the minimum thrust (displacement) in FIG. 9 to the position of the maximum thrust (displacement) in FIG.

The housing of the shift control valve 2 has a line pressure port 2a communicating with a line pressure circuit, a piston pressure port 2b communicating with an input pulley piston chamber, and a drain port 2c, each of which has a predetermined surface facing the spool 5. Open at the position. The lands 5a, 5b, and 5c are formed on the spool 5 at predetermined intervals from the left side in the figure.

The shift control valve 2 supplies and discharges hydraulic oil to and from the piston pressure port 2b by displacing the spool 5 in accordance with the thrust of the solenoid 4 against the spring 9, thereby changing the speed ratio of the continuously variable transmission. Is adjusted, and the characteristics of the shift control valve 2 are as shown in FIG.

When the solenoid 4 is in a non-operating state, the spool 5 is urged by the spring 9 and the spool 5 shown in FIG.
Of is in most retracted position, the minimum thrust position of FIG. 10 in the section E _1. In this position, the lands 5a and 5b respectively block the drain port 2c and the line pressure port 2a,
Since the pressure oil in the input pulley piston chamber is sealed, a predetermined gear ratio is maintained.

When the extension drive of the solenoid 4 is started, the spool 5 is displaced to the left in FIG. 9A from FIG. 9A, and the oil passage between the lands 5a and 5b is formed as shown in FIG. 9B. The piston pressure port 2b and the drain port 2c communicate with each other, and the pressure oil in the input pulley piston chamber is discharged, thereby causing a downshift. According to the displacement of the spool 5, the communication of the piston pressure port 2b and the drain port 2c (opening area of the port) is changed, the communication amount in accordance with the displacement of the spool 5 enters the section F ₁ in FIG. 10 The spool 5 further increases from the point Dmax where the communication amount is the maximum position on the downshift side shown in FIG. 10 and the signal use range R in FIG.
When the vehicle enters NG, the communication amount on the downshift side gradually decreases to the neutral position (center) shown in FIG. 9C. In this neutral position, the land 5b seals the piston pressure port 2b, so that a predetermined gear ratio is maintained as in the case of the minimum thrust position.

Further, when the solenoid 4 drives the spool 5 to the left in the figure, the line pressure port 2a and the piston pressure port 2b communicate with each other through an oil passage between the lands 5b and 5c.
Pressure oil is supplied to the input pulley piston chamber, and the upshift shown in FIG. 9D is performed. That is, according to the displacement of the spool 5 to the left in the drawing, the communication amount between the line pressure port 2a and the piston pressure port 2b increases in the section RNG of FIG. Once in section F ₂ in FIG. 6 communicating amount upshift side shown in FIG. 10 is displaced further spool 5 from Umax maximum points are the location, communication amount to the upshift side, conversely It gradually decreases according to the displacement of the spool 5. When further enters the section E ₂ in FIG. 10, it is blocked again line pressure port 2a and the drain port 2c Portland 5b, by 5c, maximum thrust position shown in the thrust of the solenoid 4 is maximized FIG 9 (E) ( Operating state). At this maximum thrust position,
The supply and discharge of the hydraulic oil to / from the piston pressure port 2b is not performed, and the predetermined gear ratio is maintained as in the case of the minimum thrust position.

In FIG. 10, among the signals output from the control unit, the signal value to the solenoid 4 at which the spool 5 is in the neutral position is defined as a neutral value N. In a predetermined range including the neutral value N, the input pulley piston Hydraulic oil is sealed in the chamber and the gear does not shift.

The control unit, which determines the target gear ratio in accordance with the driving state of the vehicle by means of the gearshift control valve 2 as described above, sends an operation amount to an actuator such as a solenoid 4 to change the actual gear ratio to the target gear ratio. Match the ratio.

FIG. 10 shows a control unit.
Of the signal output range, a signal is output in a section RNG (signal use range) between the lower limit value Dmax and the upper limit value Umax, and the solenoid 4 is in a non-operating state (at a minimum thrust) or a maximum operating state (a maximum thrust). In this case, the piston pressure port 2b of the input pulley is sealed to prohibit the supply and discharge of the hydraulic oil, so that when a failure occurs in the control unit, the solenoid 4, or the like, a rapid shift operation occurs. In this case, stable feedback control is performed while avoiding the use of a region where the control gain is negative (diverging) while ensuring fail-safe.

[0013]

By the way, the dimensional tolerance of each port of the housing constituting the transmission control valve 2 and the land of the spool 5, the tolerance of the spring constant of the spring 9, or the variation of the thrust of the solenoid 4, etc. The signal output value from the control unit and the communication amount to the input pulley piston chamber also vary. For example, when the spring constant of the spring 9 of the shift control valve 2 is larger than a design value, the spool 5 is displaced by a predetermined amount. In order to do so, a larger thrust is required by the solenoid 4, and the relationship between the signal output value and the communication amount is shifted.

However, in the above-mentioned conventional example, the control unit outputs the signal use range R between the preset upper limit value Umax and the lower limit value Dmax out of the signal output range.
Since the control was performed by NG, the communication amount to the input pulley piston chamber with respect to the signal output value of the control unit was changed from the solid line a in the normal state shown in FIG. If there "deviation", the upper limit value Umax and the lower limit value Dmax of the signal range of use, U ₁ that communicates the maximum amount each of the line pressure side and the drain side,
There is a problem that the speed does not coincide with D ₁ and the speed of the speed change is reduced and the speed change control becomes unstable. For example, in FIG.
The signal output value from the control unit a Umax, if the maximum upshift has been requested, the actual communication amount becomes U ₁ 'on the broken line b, communicating the amount of line 11 pressure side is maximized Narazu, transmission rate will be lower than the predetermined design value, also, the signal output value becomes a Dmax, when the maximum downshift has been requested, the actual communication amount D ₁ of the on broken lines b As a result, the communication amount on the drain side exceeds the maximum value, the control gain enters a negative range, and as the shift request increases, the shift speed may decrease or shifting may not be possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has been made in consideration of the above-described problem. The purpose of the present invention is to always perform stable shift control while preventing a shift from occurring, and to effectively exhibit the performance of a shift control valve to obtain a shift speed as designed.

[0016]

According to a first aspect of the present invention, as shown in FIG. 11, an input pulley and an output pulley whose contact pulley width of a belt is variably controlled based on a hydraulic pressure are formed on the input / output pulley. A piston chamber for changing the pulley width, a line pressure supply means for supplying a predetermined line pressure to the piston chamber of the output pulley, and hydraulic oil to the piston chamber of the input pulley through a line pressure port or a drain port. A shift control valve that supplies and discharges according to the amount of communication with one side;
An actuator that drives the shift control valve, a shift control unit that drives the actuator based on an operation amount calculated according to a driving state of the vehicle, and an actuator that is formed in the shift control valve and that is in a non-operating state or A shift inhibiting means for inhibiting supply and discharge of hydraulic oil to and from the input pulley piston chamber in a maximum operation state; and an operation amount regulating means for regulating the operation amount so as not to exceed predetermined upper and lower limits. Learning control means for changing an operation amount of the actuator from the minimum operation state to the maximum operation state or from the maximum operation state to the minimum operation state, and a shift control valve for the shift control valve. Position detecting means for detecting the position of the valve body at least at the minimum displacement position and the maximum displacement position; and the detected position is the minimum displacement position of the valve body. The operation amount at the time, the operation amount learning means for respectively detecting the operation amount when the valve element is at the maximum displacement position, the operation amount at the minimum displacement position of the valve element respectively detected by the operation amount learning means, Control range correcting means for correcting the upper limit value and the lower limit value based on the operation amount at the maximum displacement position of the valve element.

In a second aspect based on the first aspect, the learning command means includes a start detecting means for detecting a start state of the engine, and starts changing the manipulated variable after the engine is started.

In a third aspect based on the first aspect, the learning command means includes a stop state detecting means for detecting a stop state of the vehicle, and a stop position detecting means for detecting that the shift position has changed from the running state to the stop position. And a shift operation detecting means for detecting the shift amount. The change of the operation amount is started when the vehicle is stopped and the shift position is changed from the running state to the stopped position.

In a fourth aspect based on the first aspect, the learning instruction means changes the operation amount between the minimum operation state and the maximum operation state over a predetermined time.

According to a fifth aspect of the present invention, in the first aspect, the control range correction means includes a use range calculation means for calculating an operation amount use range from a minimum displacement position to a maximum displacement position of the valve element; A lower limit correction unit that updates a value corresponding to the operation amount use range to the operation amount at the minimum displacement position of the valve body as the lower limit, and from the operation amount at the maximum displacement position of the valve body to the operation amount use range. And an upper limit value correcting means for updating a value obtained by subtracting the corresponding value as the upper limit value.

In a sixth aspect based on the first aspect, the control range correcting means calculates a median value of a maximum displacement position from a minimum displacement position of the valve element;
Lower limit correction means for updating a value obtained by subtracting a predetermined value from the median value as the lower limit value, and upper limit value correction means for updating a value obtained by adding a predetermined value to the median value as the upper limit value

[0022]

Accordingly, the first aspect of the present invention relates to a dimensional tolerance of each port of a housing and a valve body constituting a shift control valve,
Due to variations in the thrust of the actuator, etc., the amount of operation of the actuator and the amount of communication of the on-shift control valve also vary.However, the actuator is driven from the minimum operation state to the maximum operation state to obtain the minimum displacement position of the valve body. And the operation amount B at the maximum displacement position are respectively detected, and the upper limit value Umax and the lower limit value Dm are obtained from these operation amounts A and B.
To correct ax, subsequent shift control is performed within a control range that compensates for deviations between the operation amount due to dimensional tolerances and aging of each part and the flow characteristics of the shift control valve, and accurate shift control can always be performed. In addition, since the control accuracy of the continuously variable transmission is greatly improved, and the control range is restricted between the corrected upper limit value Umax and the lower limit value Dmax, the control gain becomes negative and the shift speed decreases and the shift speed is reduced. The impossibility of being disabled can always be accurately prevented without being affected by changes over time.

According to the second aspect of the present invention, the control range is corrected each time the engine is started, so that accurate control can be always performed regardless of the aging of each part or the change of the use environment. As a result, the reliability of the continuously variable transmission can be improved.

According to the third aspect of the present invention, the control range is corrected each time the vehicle is stopped and the shift position is switched from the traveling position to the stopped position. As a result, the flow characteristics of the shift control valve due to operating conditions and environmental changes can be corrected each time the vehicle stops, and changes in the flow characteristics can be quickly corrected to further improve the accuracy of shift control. .

According to the fourth aspect of the present invention, since the actuator gradually drives the valve element from the minimum displacement position to the maximum displacement position or from the maximum displacement position to the minimum displacement position over a predetermined time, the position detection can be accurately performed. To perform accurate correction.

According to a fifth aspect of the present invention, the operation amount use range from the minimum displacement position to the maximum displacement position of the valve body is determined,
The value obtained by adding the value corresponding to the operation amount use range to the operation amount A at the minimum displacement position of the valve body is updated as the lower limit value, and the value corresponding to the operation amount use range from the operation amount B at the maximum displacement position of the valve body Is updated as the upper limit value, the correction operation can be easily performed.

According to a sixth aspect of the present invention, a median of a maximum displacement position from a minimum displacement position of a valve body is obtained, and a value obtained by subtracting a predetermined value from the median value is updated as a lower limit value, and the predetermined value is updated to the median value. Since the value obtained by adding the values is updated as the upper limit value, the correction operation can be easily performed.

[0028]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a shift control device of a V-belt type continuously variable transmission. A continuously variable transmission 17 includes an input pulley 1 connected to an engine (not shown) as a variable pulley.
6 and an output pulley 26 connected to a drive shaft, and these variable pulleys are connected by a V-belt 24.

The input pulley 16 has a fixed conical plate 22 which rotates integrally with a shaft connected to an engine (not shown).
The movable conical plate 18 is disposed opposite to the fixed conical plate 22 to form a V-shaped pulley groove, and can be displaced in the axial direction according to the hydraulic pressure acting on the input pulley piston chamber 20 from the transmission control valve 2. Consists of

On the other hand, the output pulley 26 has a fixed conical plate 30 which rotates integrally with a shaft connected to the axle, and is arranged to face the fixed conical plate 30 to form a V-shaped pulley groove. It is composed of a movable conical plate 34 that can be displaced in the axial direction according to the line pressure from the hydraulic control unit 3 acting on the pulley piston chamber 32.

The shift control for changing the widths of the V-shaped pulley grooves of the input pulley 16 and the output pulley 26 is performed by the shift control valve 2 for adjusting the supply and discharge of the hydraulic oil to and from the input pulley piston chamber 20. Will be

That is, the CVT control unit 1
The hydraulic pressure applied to the input pulley piston chamber 20 is controlled by a hydraulic control unit 3 composed of a solenoid 4 acting as an actuator in response to a command from the solenoid and a shift control valve 2 driven by the solenoid 4, and the like. The solenoid 4 has the same configuration as that of the conventional example shown in FIG. 9, and the same components are denoted by the same reference numerals and the description thereof will not be repeated. The shift inhibiting means includes lands 5a, 5b, 5c that seal input pulley piston chamber 20 when solenoid 4 is in a non-operating state or a maximum operating state.
(See FIG. 9) is formed on the spool 5 of the transmission control valve 2.

The shift control valve 2 is provided with limit switches 41 and 42 for detecting both ends of the stroke range of the spool 5 shown in FIG. 9, and the limit switch 41 is shown in FIG. As described above, when the spool 5 is at the most contracted position (minimum displacement position), it is turned ON (= 1), while the limit switch 42 is set at the most extended position of the spool 5 as shown in FIG. (Maximum displacement position), it turns ON (= 1), and these limit switches 41,
The signal from 42 is input to the CVT control unit 1.

The hydraulic control unit 3 includes:
A line pressure supply unit (not shown) is provided to supply a predetermined line pressure to the output pulley piston chamber 32 and the shift control valve 2.

The CVT control unit 1 mainly composed of a microcomputer or the like operates a deviation between the target speed ratio and the actual speed ratio so that the target speed ratio calculated based on the driving state of the vehicle is made to coincide with the actual speed ratio. Is instructed to the solenoid 4 in accordance with the operation amount.

Such a CVT control unit 1
An example of the speed change control performed in step (1) will be described in detail with reference to flowcharts in FIGS.

In step S1, the input rotation speed Nin and the output rotation speed Nout (= vehicle speed VSP) from the continuously variable transmission 17 are calculated.
In addition to reading the throttle opening TVO according to the driver's operation and the signal (shift mode and the like) from the inhibitor switch 8, the engine speed Ne is read from an engine control unit (not shown), and the target shift according to the driving state of the vehicle is performed. While calculating the ratio, the continuously variable transmission 17
Then, the deviation between the actual speed ratio and the target speed ratio is calculated.

Deviation = actual gear ratio−target gear ratio (1) In step S 2, the operation amount of the solenoid 4, that is, the target position of the spool 5 of the shift control valve 2 is calculated based on the deviation by feedback control or the like. .

When this shift control is performed by, for example, PID (proportional, integral, differential) control, the manipulated variable is calculated as in the following equation.

Manipulated variable = neutral value N + gain for P × deviation + gain for I × ∫ deviation dt + gain for D × d / dt deviation (2)

As shown in FIG. 6, the neutral value N indicates that the solenoid 4 that drives the spool 5 against the spring 9 has the entire stroke range of the spool 5 (= solenoid 4).
(Signal output range), the operation amount (signal output value) for driving the spool 5 so as to be at the neutral position in FIG.
In this neutral position, the land 5b of the spool 5 shuts off the piston pressure port 2b and maintains a predetermined gear ratio, as in the conventional example.

From the above equation (2), the operation amount of the solenoid 4 is obtained as a value from the neutral value N corresponding to the deviation.

Next, in step S3, the above step S2
It is determined whether or not the operation amount obtained in is less than or equal to a preset upper limit value Umax. If the operation amount exceeds the upper limit value Umax, the process proceeds to step S4 to regulate the operation amount to the upper limit value Umax.

Further, in step S5, the above-mentioned step S
It is determined whether or not the operation amount obtained in step 2 is equal to or greater than a preset lower limit value Dmax. If the operation amount is less than the lower limit value Dmax, the process proceeds to step S6 to regulate the operation amount to the lower limit value Dmax.

Here, the upper limit value Umax and the lower limit value Dmax
In the following flow chart of FIG. 3, when a predetermined condition is satisfied, the correction processing shown in the flow chart of FIG. 4 is performed, and the correction processing shown in the flow chart of FIG. The upper limit Umax and the lower limit Dmax are corrected.

First, in step S10 of FIG. 3, the signal from the inhibitor switch 8 is "N" (neutral).
Alternatively, it is determined whether the vehicle is stopped based on whether or not the vehicle is at the “parking” position. If the vehicle is stopped, the process proceeds to step S11. If the vehicle is running, the process proceeds to step S15, and the upper limit Umax and the lower limit Dmax are determined. The detection flag for performing the correction process is reset to 0, and the process ends.

In step S11, the engine speed Ne
Is greater than or equal to a predetermined idle speed, the operating state of the engine is determined. If the engine is running, the process proceeds to step S12, while if the engine is stopped, the process proceeds to step S14, and the preparation flag Is set to 1, the process proceeds to step S15, and the process ends. The preparation flag is a variable indicating whether or not the engine is waiting for starting.

In step S13, it is determined whether or not the preparation flag is "1". If the preparation flag is "1", the process proceeds to step S13, where the detection flag is set to "1" and the preparation flag is set to "0". Reset to.

Therefore, the above steps S10 to S1
In 5, when the vehicle is stopped and the engine starts,
The detection flag is set to 1.

Next, the flowchart of FIG. 4 for correcting the upper limit Umax and the lower limit Dmax will be described.

First, in step S20, it is determined whether the detection flag processed in the flowchart of FIG. 3 is 1 or not. If the detection flag is 0, step S31 is executed.
Then, the operation amount is calculated by the normal control. On the other hand, if the detection flag is 1, the upper limit value Uma after step S21 is obtained.
The process proceeds to detection processing of x and the lower limit value Dmax.

In step S21, the variable COUNT is set to 0.
It is determined whether the current loop is the first loop by comparing whether the value is greater than or not. If the variable COUNT is 0, it is determined that the current loop is the first loop, and the process proceeds to step S22. Is set to a predetermined minimum value (for example, 0) to drive from the minimum operation state, and to set the variable COUN
Set T to 1.

Next, in step S23, it is determined whether or not the limit switch 41 is OFF. If the limit switch 41 is OFF, the process proceeds to step S25. If not, the process proceeds to step S24 to turn the limit switch 41 ON. When this happens, the operation amount at the minimum displacement position is set to the stroke start value A.

In step S25, the limit switch 4
It is determined whether or not 2 is ON. If it is ON, the process proceeds to step S29 and subsequent steps. If not, the process proceeds to step S26, and the operation amount while the limit switch 42 is OFF is set to the stroke end. Set to value B.

After setting the operation amount to the stroke start value A or the stroke end value B in steps S24 and S26, the flow advances to step S27 to add a predetermined increment value .DELTA.Inc to the operation amount and to operate the solenoid 4. The operation amount is increased so as to perform the extension drive by the fixed amount.

In step S28, it is determined whether or not the operation amount is the maximum operation state in which the operation amount has reached a predetermined maximum value. If the operation amount is equal to or less than the maximum value, the process proceeds to step S32. While the increased operation amount is output to the solenoid 4, if the operation amount exceeds the predetermined maximum value, the process proceeds to step S29, where the upper limit value Umax and the lower limit value Dmax are updated as in the following equation.

Upper limit value Umax = B-α · C Lower limit value Dmax = A + α · C where C = BA α = a predetermined constant (0 <α <0.5).

That is, as shown in FIG.
From the operation amount at the minimum displacement position where displacement actually started against the spring 9 = stroke start value A, the operation amount at the maximum displacement position where displacement of the spool 5 actually ended = stroke end value B The section C up to the shift control valve 2
Is a drive range that can be actually operated, and a new upper limit value Umax and a lower limit value Dmax are calculated from a value obtained by multiplying the drive range by a predetermined constant α.
Is updated, and the signal use range RNG for driving the shift control valve 2 due to dimensional tolerances and aging of each component is updated.
The constant α is a value set in advance from the relative positional relationship between the land and the port of the spool 5 as shown in FIG.

When this correction processing is completed, step S3
At 0, the detection flag is reset to 0, and the variable COUNT is reset to 0 to prepare for the next processing.
After the operation amount is calculated by the normal control in step S32,
To drive the solenoid 4 to return to the normal shift control.

The increment value ΔInc is set so that the time from the minimum value to the maximum value is about 2 seconds.
The detection accuracy can be improved, and more accurate correction can be performed.

By executing the flowcharts of FIGS. 2 to 4 at predetermined time intervals, first, the detection flag is set to 1 after the engine is started, so that the solenoid 4 is moved from the most contracted position (minimum operation state) to the maximum. When the spool 5 is driven only once to the extension position (maximum operation state) and the spool 5 actually starts displacing against the spring 9, the operation amount = stroke start value A, and the displacement of the spool 5 is actually ended. When the operation amount at the time = stroke end value B is detected, a signal output range C in which the spool 5 can be actually driven is obtained. Based on the detected stroke start value A and stroke end value B, the upper limit value Umax is obtained. And the signal use range RNG set by the lower limit value Dmax is updated.

Now, as shown in FIG. 6, the dimensional tolerance of each port of the housing and the land of the spool 5 constituting the shift control valve 2, the tolerance of the spring constant of the spring 9, the variation of the thrust of the solenoid 4, and the like. , The signal output value from the CVT control unit 1 and the amount of communication with the input pulley piston chamber 20 also vary. For example, when the spring constant of the spring 9 of the shift control valve 2 is larger than a design value, the spool 5 is removed. In order to displace by a predetermined amount, a large thrust is required by the solenoid 4, and the relationship between the signal output value and the communication amount shifts from a to b in the figure, but after the start of the engine, the solenoid 4 Drive from the most contracted position to the most extended position only once and
, And the upper limit Umax and the lower limit Dmax from the signal output range C in which the spool 5 can be actually driven to the upper limit Umax 'and the lower limit Dmax', respectively. Updating and subsequent shift control are performed within a signal use range RNG 'in which an error between a signal output value and a communication amount due to a dimensional tolerance or a change with time of each component is corrected.

In this way, the spool 5 is driven to learn and correct the flow characteristic of the shift control valve 2 each time the vehicle is stopped and each time the engine is started. The relationship between the signal output value to the solenoid 4 that drives the valve 2 = the operation amount and the communication amount according to the displacement of the spool 5 is always constant, and the transmission control value of the shift control valve 2 due to aging, dimensional tolerance, etc. By correcting the control characteristics every time the engine is started, accurate shift control can always be performed, and the control accuracy of the continuously variable transmission is greatly improved.
In order to regulate the signal use range RNG 'between the upper limit value Umax' and the lower limit value Dmax 'updated after the engine is started, the control gain becomes negative and the shift speed decreases or the shift cannot be performed. Therefore, it is possible to prevent the problem accurately at all times.

Also, in the same manner as in the conventional example, since the spool 5 is constantly driven within the signal use range RNG as described above, the solenoid 4 is in the non-operating state (at the time of the minimum thrust) or the maximum operating state (the maximum thrust). At time), the piston pressure port 2b of the input pulley is sealed to prohibit the supply and discharge of hydraulic oil, so that the CVT control unit and the solenoid 4
When a failure occurs, for example, a sudden shift operation is prevented from occurring and fail-safe is ensured.

FIG. 7 is a flowchart showing the second embodiment, which is executed in place of the flowchart shown in FIG. 3 of the first embodiment.
This is the same as the embodiment.

The flowchart of FIG. 7 sets a detection flag for determining whether or not to execute the correction processing shown in the flowchart of FIG.
At 0, it is determined whether the vehicle speed VSP is 0 km / h, that is, whether or not the vehicle is stopped. If the vehicle is stopped, the process proceeds to step S41. If the vehicle is running, the process proceeds to step S46, and the upper limit value Umax is set. Then, the detection flag for performing the correction process of the lower limit value Dmax is reset to 0, and the process ends.

In step S41, it is determined whether the vehicle is stopped based on whether the signal from the inhibitor switch 8 is in the "N" (neutral) or "parking" position. If the vehicle is stopped, the process proceeds to step S43. If it is another driving range (drive D or the like), step S4
After setting the engagement flag to 1, the detection flag for correcting the upper limit value Umax and the lower limit value Dmax is set to 0.
To end the process.

When the engagement flag is 1, it indicates that the vehicle is stopped and the shift position is in the travel range, and a clutch (not shown) provided on the input side or output side of the continuously variable transmission 17 is engaged. Indicates that it is.

Then, in a step S43, it is determined whether or not the above-mentioned engagement flag is "1". If the engagement flag is "1", the process proceeds to a step S44, where the detection flag is set to "1" and the upper limit value Umax and The correction processing of the lower limit Dmax is set to be performed, and the engagement flag is reset to 0 to prepare for the next processing. On the other hand, if the engagement flag is 0 in step S43, the process ends.

Therefore, every time the vehicle stops and the shift position is switched from the driving range such as the drive D to the N or P stopping position, the upper limit value Umax and the lower limit value Dmax shown in the flowchart of FIG. Is performed, the flow characteristics of the transmission control valve 2 caused by the operating conditions and environmental changes are stopped in addition to the correction of the flow characteristics caused by the aging and dimensional tolerances as in the first embodiment. Therefore, the change of the flow rate characteristic can be quickly corrected, and the accuracy of the shift control can be further improved.

FIG. 8 shows a third embodiment, in which the first
In the flowchart of FIG.
The calculation of the upper limit Umax and the lower limit Dmax of 29 is changed, and the other configuration is the same as that of the first embodiment.

In FIG. 4, a new neutral value (median value) N is obtained from the following equation based on the stroke start value A and the stroke end value B obtained by driving the spool 5.

Neutral value N = (B−A) / 2 Upper limit Umax = N + β Lower limit Dmax = N−β where β is a preset constant, and as shown in FIG. Is determined from the relative positional relationship.

In this way, the upper limit Umax and the lower limit Dmax can be obtained in the same manner as in the first embodiment, and these calculations can be easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a shift control device of a belt-type continuously variable transmission, showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a shift control performed by the CVT control unit of the present invention.

FIG. 3 is a flowchart for setting a detection flag.

FIG. 4 is a flowchart showing a correction process.

FIG. 5 shows the amount of drive of an actuator, the displacement of a spool, and the amount of communication of a shift control valve.

FIG. 6 is a graph showing the relationship between the operation amount (spool position) from the CVT control unit to the solenoid of the present invention and the communication amount between the piston chamber and the line pressure port or the drain port.

FIG. 7 is a flowchart showing a second embodiment, in which a detection flag is set.

FIG. 8 shows a third embodiment, showing how upper and lower limits are corrected from a neutral value, the amount of operation from the CVT control unit to the solenoid (the position of the spool), the piston chamber and the line pressure port. Alternatively, a graph showing the relationship between drain port communication amounts.

FIG. 9 is a schematic view showing a shift control valve, where (A) shows the position of the spool when the thrust of the solenoid is at a minimum, and (B)
Indicates the position of the spool when the continuously variable transmission is downshifted,
(C) also shows the neutral position of the spool, (D) shows the spool position in the upshift state, and (E) shows the spool position when the thrust of the solenoid is maximum.

FIG. 10 is a graph showing a conventional example, showing a relationship between an operation amount from a CVT control unit to a solenoid and a communication amount of a shift control valve.

FIG. 11 is a diagram corresponding to claims of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CVT control unit 2 Shift control valve 2a Line pressure port 2b Piston pressure port 2c Drain port 3 Hydraulic control valve 4 Solenoid 5 Spool 5a, 5b, 5c Land 6 Input speed sensor 7 Output speed sensor 9 Spring 16 Input pulley 17 None Step transmission 18 Movable conical plate 22 Fixed conical plate 20 Input pulley piston chamber 24 V belt 26 Output pulley 30 Fixed conical plate 32 Output pulley piston chamber 34 Movable conical plate 41, 42 Limit switch 100 Shift control means 101 Input pulley 102 Output pulley 103, 104 Piston chamber 105 Line pressure supply means 106 Shift control valve 107 Actuator 100 Shift control means 108 Shift inhibition means 110 Operation amount regulation means 111 Learning command means 112 Position detection means 113 Control range correction means 114 Operation amount learning means

Claims (6)

(57) [Claims] An input pulley and an output pulley in which a width of a contact pulley of a belt is variably controlled based on a hydraulic pressure, a piston chamber formed on each of the input and output pulleys to change a pulley width, and a piston chamber of the output pulley. A line pressure supply means for supplying a predetermined line pressure to the line, a shift control valve for supplying and discharging hydraulic oil to the piston chamber of the input pulley according to a communication amount with one of a line pressure port or a drain port, An actuator for driving the shift control valve; a shift control means for driving the actuator based on an operation amount calculated according to a driving state of the vehicle; and a shift control valve formed in the shift control valve so that the actuator is in a non-operating state or A shift prohibiting unit that prohibits the supply and discharge of hydraulic oil to and from the input pulley piston chamber when in the maximum operation state; A shift control device for a belt-type continuously variable transmission including an operation amount restricting unit that restricts the operation amount so as not to exceed a limit value, such that the actuator moves from a minimum operation state to a maximum operation state or from a maximum operation state to a minimum operation state. Learning command means for changing the operation amount; position detecting means for detecting the position of the valve element of the shift control valve at least at the minimum displacement position and the maximum displacement position; and the detected position is the minimum displacement position of the valve element. The operation amount at the time, the operation amount learning means for respectively detecting the operation amount when the valve body is at the maximum displacement position, the operation amount at the minimum displacement position of the valve body respectively detected by the operation amount learning means, the valve Shift control for a belt-type continuously variable transmission, comprising: control range correction means for correcting the upper limit value and the lower limit value based on the operation amount at the maximum displacement position of the body. Location. 2. The system according to claim 1, wherein the learning command unit includes a start detecting unit that detects a start state of the engine, and starts changing the operation amount after the engine is started.
3. The shift control device for a belt-type continuously variable transmission according to claim 1. 3. The learning command means includes a stop state detecting means for detecting a stop state of the vehicle, and a shift operation detecting means for detecting that the shift position has changed from the running state to the stop position. The shift control device for a belt-type continuously variable transmission according to claim 1, wherein the change of the operation amount is started when the state and the shift position change from the running state to the stop position. 4. The belt-type continuously variable transmission according to claim 3, wherein the learning command unit changes the operation amount between the minimum operation state and the maximum operation state over a predetermined time. Transmission control device. 5. The control range correcting means calculates a use amount operation range from a minimum displacement position to a maximum displacement position of the valve body, and a use range calculation means calculates an operation amount use range at the minimum displacement position of the valve body. A lower limit correction means for updating a value obtained by adding a value corresponding to the range as the lower limit value, and a value obtained by subtracting a value corresponding to the operation amount use range from the operation amount at the maximum displacement position of the valve body as the upper limit value. The shift control device for a belt-type continuously variable transmission according to claim 1, further comprising an upper limit value correcting unit that performs the operation. 6. The control range correction means calculates a median value of a maximum displacement position from a minimum displacement position of the valve body, and updates a value obtained by subtracting a predetermined value from the median value as the lower limit value. 2. The belt-type continuously variable transmission according to claim 1, further comprising: a lower limit correction unit configured to perform a lower limit correction unit that updates a value obtained by adding a predetermined value to the median value as the upper limit value. 3. Transmission control device.