JPH0536641B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an oil temperature correction device for a control valve that performs duty control.

(Prior Art) As a method of controlling the flow rate of hydraulic oil supplied to a hydraulic cylinder, there is a so-called duty control in which a control valve is opened and closed intermittently to change the ratio of the valve's open state per unit time. for example,
Duty control is performed when controlling the moving speed of a hydraulic cylinder as an actuator for clutch engagement/disengagement in a vehicle with an automatic transmission, a lift cylinder in a forklift, or a piston rod of a tail cylinder. When performing duty control, the relationship between the duty ratio at a reference temperature and the flow rate of hydraulic oil supplied to the hydraulic cylinder, that is, the operating speed of the piston rod, is determined in advance, and the predetermined rod operating speed is determined based on that relationship. Set the duty ratio as follows.

(Problem to be Solved by the Invention) When performing duty control, there is no problem if the temperature of the hydraulic oil is always constant, but since the viscosity of the hydraulic oil changes with changes in temperature, it is difficult to control the duty ratio even if the duty ratio is the same. However, there is a problem in that the flow rate of the hydraulic oil changes due to changes in temperature, which causes the operating speed of the piston rod to fluctuate. Further, when controlling the operating speed of the piston rod over a wide range, two sets of valves may be used, one for controlling the high-speed portion and the other for controlling the low-speed portion. When using two sets of valves like this, the duty of the low speed valve (S valve) is
After reaching 100%, the valve was switched to the high-speed valve (F valve), and the initial duty of the high-speed valve was set to a constant value when switching the valve. Therefore 2
When using a set of valves, in addition to fluctuations in actuator (piston rod) speed due to changes in the temperature of the hydraulic oil, as shown in Figure 5, if the temperature of the hydraulic oil is at a temperature T other than the reference temperature To. However, there is a problem in that a smooth change in actuator speed cannot be obtained when switching from a low-speed valve to a high-speed valve.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a duty-controlled valve for controlling the flow rate of hydraulic fluid supplied to a hydraulic cylinder. A plurality of control valves whose flow rates in % are different from each other and are used in a switched manner, an oil temperature detector that detects the temperature of the hydraulic oil, a duty ratio corresponding to the temperature of the hydraulic oil for each control valve, and the hydraulic cylinder. a storage device in which a relationship between a variable corresponding to the flow rate of hydraulic oil supplied to the oil temperature detector is stored as data; An indexing means for determining a duty ratio at which the flow rate of hydraulic oil for each control valve becomes a preset value, and a duty ratio determined by the indexing means for the control valve in use is within a preset certain range. valve designating means for continuing to designate the control valve as the valve to be used when the control valve is within a predetermined range, and switching and designating the control valve next to the control valve as the valve to be used when the control valve is outside a preset certain range; An arrangement is adopted in which an actuating means is provided for operating a control valve designated by the means at a duty ratio determined by the indexing means for the control valve.

(Function) In the device of the present invention, the temperature of the hydraulic oil is detected by the oil temperature detector. Then, the duty ratio corresponding to the target operating speed of the piston rod at that temperature, that is, the flow rate of the hydraulic oil, is determined, and the control valve is operated in accordance with the determined duty ratio.

On the other hand, when the duty ratio calculated for the control valve in use falls outside a preset certain range, the control valve in use is switched from the control valve in use to the next control valve, and the control valve after this switching is The initial duty of
The flow rate of hydraulic oil in the hydraulic cylinder is controlled.

(Embodiment) An embodiment in which the present invention is applied to a clutch control device for a vehicle with an automatic transmission will be described below with reference to FIGS. 1 to 4.

As shown in FIG. 2, the output of the engine 1 is transmitted to the automatic transmission 3 via a dry single plate clutch 2.
The output of the automatic transmission 3 is configured to drive the traveling drive wheels 5 back and forth at a predetermined gear ratio via the operating gear mechanism 4. The dry single-plate clutch 2 that turns on and off the output of the engine 1 has a pressure plate 6 that acts to press the clutch disk 8 against the flywheel 9 due to the biasing force of a spring 7, and acts as an actuator 10 for clutch engagement/disengagement. When the piston rod 10a of the hydraulic cylinder protrudes, the pressure plate 6 is moved in the direction away from the flywheel 9 via the lever 11, and the connection state of the clutch 2 is adjusted in accordance with the amount of protrusion of the piston rod 10a. At the same time, the connection with the output shaft of the engine 1 is disconnected.

On the other hand, in the automatic transmission 3, the gear ratio is switched between 1st speed (low speed) and 2nd speed (high speed) by driving the shift switching actuator 12, and forward and reverse driving is performed by driving the forward/reverse switching actuator 13. It is designed to be able to switch between driving and driving. Both actuators 12 and 13 are constituted by hydraulic cylinders, like the clutch engagement/disengagement actuator 10, and are driven by a hydraulic circuit shown in FIG.

From the tank 14 to the pump 15 as shown in FIG.
The hydraulic oil pumped up by the accumulator 1
6 and then supplied to the main passage 17, from which the clutch control valve mechanism 19, which is a control valve mechanism of the actuator 10 for engaging and disconnecting the clutch, is supplied to the main passage 17.
It is now supplied via the main switching valve 22 to the shift control valve mechanism 20 and the forward/reverse switching control valve mechanism 21, which are the control valve mechanisms of the shift switching actuator 12 and the forward/reverse switching actuator 13. There is. The main switching valve 22 is always closed, and hydraulic oil is supplied from the main passage 17 to the shift control mechanism 20 and the forward/reverse switching control valve mechanism 21 only while the main switching valve 22 is energized. There is.

The shift control valve mechanism 20 is composed of two electromagnetic on-off valves 23 and 24 connected in series between the main switching valve 22 and the drain passage 18, and the shift switching actuator 12 has a head side chamber 12a that can be opened and closed on both sides. It is connected to a passage connecting the valves 23 and 24, and the rod side chamber 12b is connected to the main switching valve 22. Both electromagnetic valves 23 and 24 are always open, and no hydraulic pressure acts on the head side chamber 12a and the rod side chamber 12b. With one main switching valve 22 open, one electromagnetic on-off valve 23
When the piston rod is closed, hydraulic oil is supplied only to the rod side chamber 12b, the piston rod is retracted, and the internal gear is moved to the second gear shift position.
Further, when the main switching valve 22 and one electromagnetic switching valve 23 are opened and the other electromagnetic switching valve 24 is closed, the hydraulic pressure is applied to both the head side chamber 12a and the rod side chamber 12b, and the head side chamber 12a and The piston rod is projected due to the difference in pressure receiving area with the rod side chamber 12b, and the internal gear is moved to the first speed position.

Similarly to the shift control valve mechanism 20, the forward/reverse switching control valve mechanism 21 also includes a main switching valve 22 and a drain passage 18.
Two electromagnetic on-off valves 2 connected in series between
5, 26, and the head side chamber 13a of the forward/reverse switching actuator 13 is connected to both electromagnetic on/off valves 25, 2.
6, and the rod side chamber 13b
is connected to the main switching valve 22.
The forward/reverse switching actuator 13 is driven by the same action as the shift control valve mechanism 20.

The clutch control valve mechanism 19 includes a high-speed input solenoid valve 27 capable of rapidly supplying hydraulic oil from the main passage 17 to the head side chamber 10b of the actuator 10 for clutch engagement/disconnection, and a constriction section to supply hydraulic oil from the main passage 17 to the head side chamber 10b. The head side chamber 10b includes a low speed input solenoid valve 28 that can gradually supply the hydraulic oil to the head side chamber 10b, a high speed output solenoid valve 29 that can rapidly discharge the hydraulic oil in the head side chamber 10b to the oil tank 14 through the drain passage 18, and a throttle section. A low-speed output solenoid valve 30 that can gradually discharge the hydraulic oil inside the tank 14 through a drain passage 18, and each solenoid valve 27 to 30
By controlling the opening and closing of the clutch, hydraulic oil can be supplied and discharged from the head side chamber 10b of the clutch engagement/disconnection actuator 10 at a desired speed.

Next, an electric circuit for driving and controlling each of the electromagnetic valves to adjust the flow rate of hydraulic oil supplied to the clutch engaging/disengaging actuator 10, that is, the moving speed of the piston rod 10a will be explained. The stroke detection sensor 31 as a clutch speed detector is composed of a potentiometer and detects the amount of movement of the piston rod 10a of the clutch engagement/disengagement actuator 10, and the detection signal is converted into a digital signal by an A/D converter 32. I/O interface 3
3 is output.

An oil temperature detection sensor 34 serving as an oil temperature detector for detecting the temperature of hydraulic oil is installed in the accumulator 16, and its detection signal is converted into a digital signal by an A/D converter 35 and output to the interface 33. Ru.

A central processing unit (hereinafter referred to as CPU) 36 serves as an indexing means and a valve specifying means, and a read-only memory (hereinafter referred to as ROM) 3 serves as a storage device.
operates according to the control program stored in 7,
Detection signals from each of the sensors are inputted via the input/output interface 33. Said ROM3
In addition to the control program described above, 7 contains data in which the relationship between the duty ratio corresponding to the temperature of the hydraulic oil and the actuator speed as a variable corresponding to the flow rate of the hydraulic oil supplied to the clutch engagement/disconnection actuator 10 is preliminarily prepared as data. remembered. That is,
The relationship between the duty and actuator degree (clutch speed) of two sets of valves, high-speed solenoid valves 27, 29 (referred to as F valves) and low-speed solenoid valves 28, 30 (referred to as S valves), is expressed as an S map and an F map, respectively. remembered.

Based on the oil temperature detected by the oil temperature detection sensor 34 and the data stored in the ROM 37, the CPU 36 determines a duty ratio at which the flow rate of the hydraulic oil reaches a preset value. And the CPU
36 outputs a drive control signal to the actuator drive circuit 38 as an actuating means via the input/output interface 33 based on the determined duty ratio. And actuator drive circuit 3
8 applies an applied voltage of a predetermined duty ratio to each electromagnetic valve with respect to the drive signal.

Readable and rewritable memory (RAM)
) 39 is designed to temporarily store various calculation results of the CPU 36.

Next, the operation of the apparatus configured as described above will be explained. The clutch engagement/disconnection actuator 10 is the third
It is controlled according to the flowchart shown in the figure.

When the program starts, first the CPU36
determines the operating condition of the vehicle and determines a target value for the operating speed (clutch speed) of the piston rod 10a of the clutch engagement/disengagement actuator 10 corresponding to the vehicle condition. Since the CPU 36 is designed to sample various data every 25ms,
The clutch speed is determined as the speed at which the clutch position reaches the specified position after 25 ms (step
S1).

Next, the temperature of the hydraulic oil is calculated based on the detection signal of the oil temperature detection sensor 34 (step S2). Next, the duty value at the oil temperature corresponding to the clutch speed (actuator speed) set in step S1 is read from the S map (step S1).
S3). After step S3 is executed, step S4 is subsequently executed, and it is determined whether the duty read value of the S map is 100% or not (step S4).
If the duty reading on the S map is not 100%, duty is immediately output to the S valve (step S5). Specifically, the CPU 36 outputs a predetermined drive signal corresponding to the reading duty to the actuator drive circuit 38, and the actuator drive circuit 38 applies a voltage with a predetermined duty ratio to the low-speed input solenoid valve 28 or the low-speed output solenoid valve 30. Applied, low speed solenoid valve 28, 30
is opened and closed, and the piston rod 10a is moved.

After the clutch engagement/disengagement actuator 10 is operated in step S5, the difference from the target value is calculated based on the detection signal from the stroke detection sensor 31 (step S8). This step S8
Once executed, the execution of step S1 is repeated again.

On the other hand, if the duty read value of the S map is 100% as a result of the judgment in step S4, the duty value corresponding to the clutch speed is read from the F map (step S6). Then, the duty value read from the F map is output to the F valve (step S7). That is, a drive signal corresponding to the read duty ratio is output from the CPU 36 to the actuator drive circuit 38, and the actuator drive circuit 38 applies an applied voltage corresponding to the duty to the high-speed solenoid valves 27, 2 based on this drive signal.
9. Then, the high-speed solenoid valves 27 and 29 are controlled to open and close according to the duty ratio, and the clutch engagement/disconnection actuator 10 is driven.

After step S7 is executed, step S8 is executed in the same manner as described above, and the difference from the target value is detected based on the detection signal of the stroke detection sensor 31. After that, the execution of step S1 is repeated again in the same manner as described above.

As mentioned above, this device detects the temperature of the hydraulic oil, reads the duty value corresponding to the target clutch speed from the relationship between the actuator speed (clutch speed) and the duty value at that temperature, and then operates the electromagnetic circuit based on the duty value. valve 27
~30 is controlled to open and close. That is, even if the temperature of the hydraulic oil changes, the duty value is determined with the temperature change corrected, so that a predetermined clutch speed can always be obtained. Furthermore, when operating the clutch engaging/disengaging actuator 10 using two sets of valves, that is, the S valve and the F valve, in the conventional device, the initial duty of the F valve is constant when switching the valve from the S valve to the F valve. Therefore, if the temperature of the hydraulic oil changes from the reference temperature, the clutch speed value for the S valve's 100% duty will differ from the clutch speed value for the F valve's initial duty, and the clutch speed may not be controllable. As a result, smooth changes in clutch speed could not be achieved, resulting in sudden torque fluctuations. However, in the device of this embodiment, when switching from S valve to F valve, 100% of S valve
The initial duty of the F valve is determined by calculating the duty of the F valve corresponding to the clutch speed with respect to the % duty from the F map, so even if the temperature of the hydraulic oil changes, the target clutch speed is always maintained in the entire clutch speed range. A corresponding duty ratio can be set, allowing smooth changes in clutch speed.

Note that the present invention is not limited to the above embodiments; for example, in the above embodiments, switching from the S valve to the F valve was performed at 100% duty of the S valve, but any duty other than 100% may be used. The switching may be performed at a duty value of . Further, in addition to controlling the actuator for engaging and disengaging the clutch, it is also possible to implement the present invention in a control device for a lift cylinder or a tail cylinder of a forklift.

Effects of the Invention As detailed above, according to the present invention, the temperature of the hydraulic oil supplied to the hydraulic cylinder is detected, and the duty ratio for obtaining a predetermined flow rate of the hydraulic oil is calculated in accordance with the detected temperature. Since the control valve that performs duty control is operated based on the duty ratio, the hydraulic cylinder can always be controlled with the target hydraulic pressure regardless of changes in the temperature of the hydraulic oil, and the control valve that performs duty control can be switched. In this case, the optimal initial duty ratio for the control valve after switching is calculated taking into account the temperature change of the hydraulic oil, and the control valve after switching is initially operated at this initial duty ratio, so that the hydraulic cylinder This provides an excellent effect in that the flow rate of hydraulic oil supplied to the piston rod, that is, the operating speed of the piston rod, can be smoothly controlled over a wide range.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment in which the present invention is embodied in a vehicle with an automatic transmission. Figure 1 shows a hydraulic circuit and an electric circuit, and Figure 2 shows a drive system mechanism. Figure 3 is a flowchart showing the control process, Figure 4 is a diagram showing the relationship between duty value and clutch speed, and Figure 5 is the actuator operating speed in a conventional device using two sets of control valves. FIG. Clutch disconnection actuator 10, piston rod 10a, high-speed solenoid valves 27, 29, low-speed solenoid valves 28, 30, oil temperature detection sensor 34 as an oil temperature detector, indexing means and valve designation means.
A CPU 36, a RAM 37 as a storage device, and an actuator drive circuit 38 as an actuation means.

Claims (1)

[Scope of Claims] 1. A plurality of control valves that are duty-controlled to control the flow rate of hydraulic oil supplied to a hydraulic cylinder, and whose flow rates at 100% duty are different and are used in a switched manner; The relationship between the oil temperature detector that detects the temperature of the hydraulic oil, the duty ratio corresponding to the temperature of the hydraulic oil for each control valve, and the variable corresponding to the flow rate of the hydraulic oil supplied to the hydraulic cylinder is stored as data. and a duty ratio at which the flow rate of hydraulic oil for each control valve becomes a preset value based on the oil temperature detected by the oil temperature detector and the data stored in the storage device. an indexing means for determining the duty ratio of the control valve in use, and when the duty ratio determined by the indexing means for the control valve in use is within a preset certain range, the control valve is continuously designated as the used valve; valve designating means for switching and designating a control valve next to the control valve to be used when the control valve is out of a certain range; and a control valve designated by the valve designation means being indexed by the indexing means for the control valve. An oil temperature correction device for a control valve that performs duty control, and is provided with an actuating means for operating at a specified duty ratio.