JP3437085B2 - Driving method of solenoid valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a solenoid valve, for example, in a solenoid valve used for controlling operating hydraulic pressure in an automatic transmission for a vehicle or the like, characteristic variations due to variations in set load of return springs and the like are suppressed. Related to correction technology.

[0002]

2. Description of the Related Art Conventionally, in automatic transmissions for vehicles,
A mechanism is known in which the opening area of the oil passage is changed by displacing the plunger of the solenoid valve, thereby adjusting the hydraulic pressure to various friction engagement elements (clutch, brake, etc.). Here, in the solenoid valve, generally, a return spring (elastic member) for urging the plunger in one direction is provided, and a magnetic force of the solenoid valve is applied against the urging force of the return spring. However, since there is a large variation in the set load of the return spring, an adjustment mechanism (adjustment screw) for adjusting the set load is provided, and the set load is individually manually adjusted by the adjustment mechanism to obtain a reference value. It was done in the line process at the time of manufacturing and assembling.

[0003]

However, providing the solenoid valve with the adjusting mechanism as described above increases the cost and the size of the solenoid valve. In the configuration in which the adjusting mechanism is manually operated to adjust the set load, there is a problem that the number of adjusting steps increases.

Therefore, instead of individually adjusting the set load of the return spring, if a system is provided in which the drive current is corrected according to the deviation of the correlation between the drive current and the hydraulic pressure due to the variation of the set load, an adjusting mechanism is provided. Is unnecessary, and it is not necessary to manually adjust the set load. However, the design characteristics of the solenoid valve are
Despite the characteristics shown by the solid line in FIG. 9, the characteristics shown by the dotted line in FIG. 9 may actually appear due to variations in the set load. In this case, the current applied to the solenoid valve Even if 0 is set to zero, the target hydraulic pressure cannot be obtained, and a negative current is required, so that the target hydraulic pressure cannot be substantially obtained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of driving a solenoid valve which can surely adjust the target pressure (or flow rate) by correcting the driving current.

[0006]

Therefore, the invention according to claim 1 is a method for driving a solenoid valve for adjusting a fluid flow rate or fluid pressure, which comprises a fluid flow rate or fluid pressure and a drive current for the solenoid valve. than the correlation as a reference, producing the solenoid valve drive current necessary for obtaining a target flow rate or target pressure more large Kunar so
And make sure to match the target flow rate or pressure for inspection.
Drive current when feedback control of drive current
And the target flow rate for the inspection based on the reference correlation or
Based on the deviation from the drive current corresponding to the target pressure,
The calibration information of the driving current is obtained in advance, the driving current for obtaining the target flow rate or the target pressure obtained from the reference correlation is corrected based on the calibration information, and the corrected driving current is given to the solenoid valve. It was configured.

According to this structure, the solenoid valve varies in the correlation between the flow rate or pressure and the drive current due to variations in the set load.
The target flow rate is adjusted by making the drive current to obtain the target flow rate or target pressure larger than that of the reference correlation, and by correcting the drive current to a value larger than the drive current obtained from the reference correlation. Alternatively, allow pressure to be obtained.

Further, the flow rate or pressure is actually adjusted by a solenoid valve in advance, and the drive current is increased or decreased while comparing the actual value of the flow rate or pressure with the target flow rate or pressure for inspection, and the target for inspection is determined. Determine the drive current from which the flow or pressure is actually obtained. And a drive current corresponding to the target flow rate or pressure for the inspection on the reference correlation,
The deviation from the drive current when the target flow rate or pressure for inspection is actually obtained is obtained as a correction request for the reference correlation. Here, since the characteristic of the solenoid valve is limited to a characteristic in which the driving current required to obtain the target flow rate or the target pressure is larger than the reference correlation,
The drive current when the target flow rate or pressure for inspection is actually obtained is larger than the drive current corresponding to the target flow rate or pressure for inspection on the reference correlation, and the drive current correction request is made. Is an increase correction.

According to the second aspect of the invention, the calibration information is obtained in advance by adjusting the flow rate or pressure of a fluid different from the fluid whose flow rate or pressure is adjusted by the solenoid valve, and the calibration information is actually flow rate or pressure. Is converted into a value for a fluid for adjusting and used. According to such a configuration, for example, when the calibration information of the solenoid valve for adjusting the oil flow rate or pressure is obtained, the calibration information is obtained by adjusting the air flow rate or pressure that is easy to handle, and the actual oil flow rate or When the pressure is adjusted, the calibration information obtained by adjusting the air is converted into oil and used.

[0010]

According to the invention described in claim 1, since the correction of the drive current is limited to the increasing direction, the negative current is not required as a result of the correction, and the solenoid valve even if there are variations, the reliable target flow rate or pressure by the correction of the driving current is obtained
Both the flow rate or pressure in the solenoid valve and the drive
Knowing the actual correlation with the
The effect is that you can

According to the second aspect of the present invention, when the flow rate or pressure is adjusted by the solenoid valve in order to know the actual correlation between the flow rate or pressure in the solenoid valve and the drive current, a fluid that is easy to handle (for example, air)
The calibration information can be obtained by adjusting the calibration information with a simple system, while the calibration accuracy can be ensured by converting and using the calibration information when the actual adjustment is performed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a diagram showing the drive of a solenoid valve according to the present invention.
1 shows a hydraulic automatic transmission for a vehicle to which the method is applied . In FIG. 1, torque of an engine 1 mounted on a vehicle (not shown) is transmitted to drive wheels (not shown) via an automatic transmission 2. The automatic transmission 2 may be either a continuously variable transmission or a stepped transmission.

Further, the control device 3 (denoted as A / TC / U in the drawing) for controlling the shift of the automatic transmission 2 is
By incorporating a microcomputer including a CPU, a RAM, a ROM, etc., and controlling a plurality of solenoid valves for adjusting the hydraulic pressure supplied to each friction engagement element (clutch, brake, etc.) of the automatic transmission 2, Automatically control the shift speed.

The solenoid valve changes the opening area of the oil passage by displacing the plunger (movable iron core) biased by the return spring by a magnetic force against the biasing force of the return spring. Thus, the hydraulic pressure supplied to each friction engagement element is controlled. For example, as shown in FIG. 2, the solenoid valve increases the drain amount and decreases the hydraulic pressure in response to an increase in the applied drive current. , Direction requiring a larger drive current to obtain the same hydraulic pressure (hatched area)
It is manufactured so that there are variations only in. That is,
It is inevitable that the set load of the return spring will vary from the manufacturing point of view, but due to the tolerance setting, it will vary only in the direction in which a larger drive current is required to obtain the same hydraulic pressure than the reference correlation. It is so arranged that no variation occurs in the direction in which the required drive current becomes smaller than the reference correlation.

The solenoid valve may have a characteristic of increasing the hydraulic pressure in response to an increase in the drive current, and in this case, as shown in FIG. 3, the hydraulic pressure is the same as that of the reference correlation. Are manufactured so as to vary only in the direction (shaded area) where a large drive current is required to obtain The control device 3 determines the target hydraulic pressure for each friction engagement element, and determines the drive current i corresponding to the target hydraulic pressure based on the correlation between the drive current i given to the solenoid valve and the hydraulic pressure. Is calculated and output to the solenoid valve, and the energization control amount of the solenoid (for example, the on-duty of the transistor) is feedback-controlled so that the current actually flowing through the solenoid valve matches the target current.

More specifically, the configuration shown in FIG. 4 is adapted to feedback control the energization of the solenoid. In FIG. 4, the target current calculation unit 51
A target current (basic value of the driving current) corresponding to the target hydraulic pressure at that time is calculated from the correlation that is a reference between the target hydraulic pressure and the driving current stored in advance.

The median value setting unit 52 sets a reference duty (median value) corresponding to the target current and outputs it as a feedforward correction amount (F / F correction amount). On the other hand, in the feedback correction unit 53, the solenoid valve 5
Then, the deviation between the detected value of the current actually flowing and the target current is obtained, and the feedback correction amount (F / B correction amount) is output by the proportional, integral, and derivative (PID) control operation based on the deviation.

Then, the feed forward correction amount (F
/ F correction amount) and the feedback correction amount (F / B correction amount), the result (duty) is a transistor (not shown) for controlling the energization amount to the solenoid valve 5.
And the on / off control of the transistor according to the duty, the energization amount of the solenoid valve 5 is controlled according to the on time ratio.

The current detection of the solenoid valve 5 is output as a terminal voltage of a resistor provided for current detection,
The voltage is input to the A / D converter 56 via the low pass filter 55 and is A / D converted. The voltage data after A / D conversion is converted into current data by the voltage / current converter 57. Then, the detection data of the current is subtracted from the target current, and the deviation obtained by the subtraction processing is output to the feedback correction unit 53 as an error amount (control deviation).

Further, a correction amount setting unit 58 is provided,
In the correction amount setting unit 58, as shown in FIG. 5, a correction current (correction value) is set according to the target current calculated by the target current calculation unit 51, and a correction gain is set according to the target current. The final correction current is the result of setting and multiplying the correction current by the correction gain. Then, the final correction current is added to the target current calculated by the target current calculation unit 51, and the addition-corrected target current is input to the median value setting unit 52 (current control means). Further, by correcting the output of the voltage-current converter 57 with the final correction current,
An error amount (control deviation) is calculated as a deviation between the corrected detection result and the target current calculated by the target current calculation unit 51.

The correction current set in the correction amount setting unit 58 is for correcting the variation in the correlation between the drive current and the hydraulic pressure due to the variation in the set load of the solenoid valve 5, and the target current calculation unit. The target current output to the median value setting unit 52 is corrected as described above in order to cope with the characteristic variation of each solenoid valve 5 without changing the setting characteristic of the target current in 51.

By the way, as described above, the variation in the correlation between the drive current and the hydraulic pressure in the solenoid valve 5 is set to occur only in the direction in which a larger drive current is required for the same hydraulic pressure than the reference correlation. Because there is
The correction current set in the target current calculation unit 51 is
The correction value is in the increasing direction (plus) in the entire target current calculated by the target current calculation unit 51. Therefore, the result of adding the correction current to the target current calculated by the target current calculation unit 51 does not have a negative value, and the drive current corresponding to the target oil pressure is always output as a positive value, and the solenoid valve The drive current of No. 5 can be reliably controlled to a value corresponding to the target hydraulic pressure.

By correcting the drive current by the above-described correction current, it is possible to compensate for the variation in the set load of the return spring of the solenoid valve 5. Therefore, the solenoid valve 5 according to the present embodiment is provided with a set load adjusting function. Has not been done. Further, if the actual current of the solenoid valve 5 is directly compared with the target current calculated by the target current calculation unit 51, feedback control is performed so as to match the target current calculated by the target current calculation unit 51. Since the correction with the correction current does not work, the current detection result is corrected with the correction current,
By comparing the detected current value after subtracting the correction current amount with the target current calculated by the target current calculation unit 51,
Similar to the case where the correction by the correction current is not performed, the feedback control is performed by using the deviation from the target current as the error amount.

The correction current set in the correction amount setting section 58 according to the target current is obtained when the air pressure is adjusted by the solenoid valve in the assembly line process of the automatic transmission. Is calculated in advance as a deviation between the indicated value of the drive current required for the above and the basic value of the drive current corresponding to the target pressure (reference drive current), and the correction current required when adjusting this air The correction gain is corrected so as to convert it into a value suitable for adjusting the oil pressure.

That is, in order to individually detect the correlation between the pressure and the drive current in the solenoid valve, it is preferable to adjust the oil pressure as in the actual machine. If it is configured to supply the oil, the size of the system becomes large, and the pollution due to the scattering of oil poses a problem. Therefore, the correction request is detected by adjusting the pressure of the air, which is easy to handle and does not cause contamination, and the deviation of the correction request due to the difference between air and oil is compensated by the correction gain to match the air. By correcting the correction current obtained and stored in advance with the correction gain,
It is designed to be converted into a correction current suitable for adjusting the oil pressure. However, the correction current converted for oil by multiplying the correction gain in advance may be stored.

The characteristic of the correction gain with respect to the drive current shown in FIG. 5 is premised on the case where the hydraulic pressure increases as the drive current increases. FIG. 6 shows an inspection machine 11 used for detecting the correction current in the assembly process of the automatic transmission. The inspection machine 11 is integrated in the case of the automatic transmission 2 in a later process. A / T unit 6 consisting of a plurality of solenoid valves 5 and the control device 3 to be attached to the automatic transmission 2 is set after the inspection process by the inspection machine 11 is completed. Mounted in the case.

The inspection machine 11 includes the A / T unit 6
An air pressure source 12 (fluid pressure source) for supplying a constant air pressure to each solenoid valve 5 is attached. Then, the air whose pressure is adjusted by each solenoid valve 5 is individually introduced into the inspection machine 11 via the pipe 11a, and the inspection machine 11
An air pressure sensor incorporated in the solenoid detects the air pressure as a result of adjustment for each solenoid.

The inspection machine 11 increases and decreases the target current (instruction value of drive current) so as to match the detected air pressure with a predetermined target pressure, and outputs it to the control device 3 to match the target pressure. At this time, a correction current as calibration information is calculated from the target current (instruction value of the driving current), and the correction current is stored in the nonvolatile storage medium (for example, flash memory) of the control device 3.
Write with the control program.

The correction current may be obtained from the current flowing through the actual solenoid valve when it matches the target pressure. However, as described above, the correction current may be obtained from the command value of the drive current. For example, it is not necessary to feed back the current value of the solenoid valve from the control device 3 to the inspection machine 11, and the man-hours and maintenance can be simplified. Here, the operation of the inspection machine 11 will be described with reference to the flowchart of FIG.

First, in S1, the supply of air pressure to each solenoid valve is started. In S2, the drive current corresponding to the target pressure (1) preset for inspection is set based on the correlation between the target hydraulic pressure and the drive current in the target current calculation unit 51, and the drive current (reference drive current) is set. )
Is output to the control device 3 as an initial value of the target current (instruction value), and the drive current corresponding to the target current is supplied to the solenoid valve 5 via the control device 3.

In S3, the air pressure adjusted by the solenoid valve 5 is detected by the air pressure sensor built in the inspection machine 11. In S4, it is determined whether or not the air pressure detected in S3 and the target pressure (1) substantially match. When the actual air pressure does not match the target pressure (1), S5
Then, by determining whether the value obtained by subtracting the target pressure (1) from the actual air pressure is a positive value, it is determined whether the actual air pressure is above or below the target pressure (1). Determine.

If the value obtained by subtracting the target pressure (1) from the actual air pressure is a positive value and the actual air pressure is higher than the target pressure (1), the process proceeds to S6 to set the target current. The air pressure is corrected by a predetermined value in the decreasing direction, and when the air pressure is lower, the process proceeds to S7, the target current is corrected by the predetermined value in the increasing air pressure, and the correction result is output to the control device 3. . That is, the target current (instruction value of the driving current) is feedback-controlled so that the actual air pressure matches the target pressure. As the feedback control operation, proportional / integral PI operation and proportional / integral / differential PI operation are performed.
A configuration using the D operation may be used.

When the actual air pressure becomes substantially equal to the target pressure (1) by the correction of the target current, S4
To S8, the reference drive current (initial value of the target current) set as corresponding to the target pressure (1) in S2 and the target pressure (1) as a result of the feedback control in S3 to S7. The difference ΔI (1) (= [target current after feedback] − [initial value]) from the target current obtained as the corresponding value is calculated.

Here, as described above, since the characteristics of the solenoid valve 5 are manufactured so as to vary only in the direction that requires a larger drive current than the reference characteristics, [target current after feedback] ≧ [initial value] Value], the difference ΔI (1) is calculated as a positive value.
In S9, a drive current corresponding to a target pressure (2) different from the target pressure (1) is obtained from the reference correlation,
This drive current is output to the control device 3 as the initial value of the target current.

At S10, the same as S3 to S7,
The target current is feedback controlled to match the actual air pressure with the target pressure (2). In S11, the difference ΔI (2) between the target current at which the target pressure (2) is actually obtained as a result of the feedback control in S10 and the initial value of the target current set in S9 is calculated. Here again, the difference ΔI (2) is calculated as a positive value based on the variation characteristic of the solenoid valve 5.

At S12, based on the above ΔI (1), ΔI (2) and the initial value of the target current when these are calculated,
The correction current (calibration information) corresponding to the target current is shown in FIG.
It is obtained by interpolation calculation as shown in. as mentioned above,
With the configuration in which the request for the entire correction current is estimated from the data of at least two points, it is possible to accurately estimate the correction current when the correction request is not a uniform value. Therefore, the target pressure may be set at three or more points, and the instruction value of the drive current when the actual air pressure reaches the target pressure may be obtained for each and used as the basic data of the interpolation calculation.

It is obvious that the interpolation is not limited to the linear interpolation. In S13, it is determined whether or not the correction current calculated in S12 is within a predetermined range. If it is within the predetermined range, it is determined that the calibration information has been correctly obtained, and the process proceeds to S14. In S14, the solenoid control program is written in the storage medium of the control device 3 (for example, flash EEPROM), and at the same time, the calculated correction current is written and stored as the correction current in the correction amount setting unit 58.

The data written as the correction current in the correction amount setting unit 58 is a correction request when the air pressure is adjusted. If the correction current is used as it is when adjusting the oil, the oil pressure can be accurately measured. The target pressure cannot be controlled. Therefore, as described above, by multiplying the correction current by the correction gain, the value is converted to a value suitable for hydraulic control and used.

In the above embodiment, a plurality of solenoid valves 5 and the control device 3 are unitized,
Although the configuration is such that the solenoid valve 5 is set in the inspection machine 11 individually, the calibration information (correction current) for each solenoid valve 5 is calculated and the calibration information for each solenoid valve 5 is stocked. When the solenoid valve 5 and the control device 3 are unitized, calibration information of the solenoid valve 5 combined with the control device 3 may be output.

In the above embodiment, the solenoid used for hydraulic pressure adjustment in the automatic transmission has been described, but it may be a solenoid valve used for flow rate adjustment. The drive current of the solenoid valve is feedback-controlled to obtain the flow rate, and from the difference between the reference drive current corresponding to the target flow rate and the drive current instruction value when the actual air flow rate matches the target flow rate. The configuration may be such that the correction current is obtained.

Further, the inspection machine 11 may also be configured so that the flow rate or pressure of oil is adjusted to obtain calibration information as a result of adjusting the flow rate or pressure of oil. The correction of the correction current by the correction gain in the quantity setting unit 58 is omitted, and the inspection machine 11 may include a hydraulic pressure sensor instead of the air pressure sensor.

[Brief description of drawings]

FIG. 1 is suitable for a method of driving a solenoid valve according to the present invention.
The figure which shows the automatic transmission for vehicles used.

FIG. 2 is a diagram showing a variation range of solenoid valves in the embodiment.

FIG. 3 is a diagram showing a variation range of the solenoid valve in the embodiment.

FIG. 4 is a block diagram showing a drive device of a solenoid valve in the automatic transmission.

FIG. 5 is a block diagram showing details of a correction amount setting unit in the drive device.

FIG. 6 is a diagram showing an inspection machine for obtaining a correction current by adjusting air pressure in the embodiment.

FIG. 7 is a flowchart showing processing contents in the inspection machine for detecting the correction current according to the embodiment.

FIG. 8 is a diagram showing a characteristic of a correction current in the embodiment.

FIG. 9 is a diagram showing an example of variation characteristics of a conventional solenoid valve.

[Explanation of symbols]

3 control device 5 solenoid 6 A / T unit 11 inspection machine 12 Air pressure source 51 Target current calculator 52 Median setting section 53 Feedback correction section 58 Correction amount setting section

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Claims (2)

(57) [Claims] 1. A method of driving a solenoid valve for adjusting a fluid flow rate or fluid pressure, wherein a target flow rate or a target pressure is set rather than a reference correlation between the fluid flow rate or the fluid pressure and a driving current of the solenoid valve. the sore on the drive current is more size Kunar so necessary to obtain
The noid valve is manufactured, and the valve is adjusted to match the target flow rate or pressure for inspection.
Drive current when feedback control of dynamic current and
The target flow rate or target pressure for the inspection based on the reference correlation
Force based on the deviation from the drive current
Previously obtained calibration information flow, based on the calibration information, the driving current for obtaining a target flow rate or target pressure calculated from the correlation to be the reference correction, to provide a drive current to the correction to the solenoid valve the driving method of the solenoid valve according to claim. 2. A pre-determined the calibration information by adjusting the flow rate or pressure of different fluids from the fluid to adjust the flow rate or pressure in the solenoid valve, the calibration information, for fluid to actually adjust the flow rate or pressure The method of driving a solenoid valve according to claim 1 , wherein
Law .