JPS61236902A - Controller for electric type proportional control valve - Google Patents

Abstract

PURPOSE:To increase the switching speed of a control valve by permitting the pass of a spool at a high speed independently of the position of an operating lever during the time when the spool passes through the insensitive band of a control valve. CONSTITUTION:During the time when a spool 430 passes through an insensitive band in which fluid passages are not switched by the shift of the spool 430, the spool 430 is controlled to pass at a high speed independently of the position of an operating lever 62. Control is performed by a controller 50 for demodulating control signals. With such constitution, the switching speed of a control valve 40 can be increased independently of the operation quantity and operation speed of an operating lever 62.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device that improves the responsiveness of an electric proportional control valve. - [Prior Art] Conventionally, as shown in Figs. 15 and 16, electric proportional control valves have a spool and a housing that are fixed at a constant position in the neutral position in order to prevent hydraulic oil from leaking between boats. There is a long overlap. Therefore, when moving the spool with pilot pressure to switch the fluid passage, while the spool passes through the overlap part,
The switching valve does not function as intended. That is, a dead zone exists.

[Problems to be Solved by the Invention] The pilot pressure for moving the spool is controlled by, for example, a duty control signal that drives a solenoid such as a poppet valve, and this control signal is output in accordance with the amount of operation of the operating lever. Ru. For this reason, when various hydraulic cylinders used in forklifts, etc. are controlled by electric proportional control valves, the presence of the dead zone results in low responsiveness of the actuator to the operating lever, resulting in poor usability. .

The present invention has been made to improve such drawbacks, and aims to improve the responsiveness of the actuator controlled by the dead zone passage time of the electric proportional control valve by shortening it as much as possible. purpose.

[Technical means for solving the problem] The present invention detects the position of the operating lever, outputs a control signal corresponding to the position, controls the amount of movement of the spool using the control signal, and controls the movement of the spool. In a control device for controlling an electric proportional control valve that switches fluid passages and adjusts flow rate by movement, a dead zone of the control valve in which the fluid passage is not switched even by movement of the spool is defined by the spool. While passing,
The electric proportional control valve control device is characterized in that it includes a modulation section that modulates the control signal so that the control signal passes through the spool at high speed regardless of the position of the operating lever.

Here, the period during which the spool passes through the dead zone can be specified by the elapsed time from the start of control or by the movement of the spool. When specifying by the amount of movement, a displacement detector that detects the displacement of the spool and a dead zone detection section that detects that the spool has passed through the dead zone based on the displacement detected by the displacement detector are provided. ,
Dead zones can be detected.

In addition, when time is used to identify the dead zone, the dead zone transit time is determined by changing the time depending on at least one of the variables such as the temperature of the fluid and the rotational speed of the engine that drives the pump that pumps the fluid. It is better to have a section. In the case of a battery-powered type, it is desirable to take the battery voltage into account. This is because the dead zone passing time differs depending on the above variables.

[Function] In the normal control state, the moving speed and amount of the spool are determined by the difficulty of operating the operating lever and the operating time.

The present invention outputs a control signal that moves the spool at high speed while the spool passes through a dead zone due to the action of the modulation section when the operation of the operating lever is started, and after passing through the dead zone, the spool moves according to the operating lever. control the movement of

Therefore, since the dead zone is passed in a short time, the fluid passages are switched quickly, and the responsiveness of actuators such as hydraulic cylinders is improved.

[Example] The present invention will be explained below based on a specific example.

FIG. 1 is a connection diagram showing the connection relationship of the device according to the embodiment of the present invention in use. The hydraulic cylinder 3-0 has cylinder chambers 31 and 32, and a pipe 401 connected to the cylinder chamber 31 is connected to the X boat of the main valve 43 of the electric proportional control valve 40, and a pipe 402 connected to the cylinder chamber 32 is connected to the X boat of the main valve 43 of the electric proportional control valve 40. is connected to the Y boat of the main valve 43 of the electric proportional control valve 40.

The input port P of the main valve 43 of the electric proportional control valve 40 is
A high-pressure pipe line 92 is connected to the input port Q, and a low-pressure pipe line 93 is connected to the input port Q. The oil in the low pressure pipe 93 returns to the tank 91, and the oil in the high pressure pipe 92 is supplied from the tank 91 to the pump 9.
The oil pumped up by 0 is pumped out. Also main valve 43
A bypass pipe line 94 for introducing pilot oil pressure for driving the main valve 43 is provided in the pipe line 94, and a poppet valve 41, 42 for driving the main valve 43 is provided in the pipe line. The main valve 43 is a four-bottom, three-position switching valve, and the position of the switching valve is controlled by pilot pressure. The poppet valves 41.42 have their solenoids 410.4
20 receives a duty control signal from the electric proportional control valve 11/J 1ill system (hereinafter simply referred to as [control system!J) 50]
V2. By inputting V3, it is controlled to continuously generate pilot pressure. Control device! 50 detects the position of the operating lever 62 of the operating box 61 and outputs a duty control signal according to the detected position.

Also, a main relief valve 95 is provided between the pressure pipe 92 and the low pressure pipe 93, and the main valve 43 is in the neutral position W4.
30, oil flows through this valve 95 to tank 91.
has returned to. Similarly, the pilot pipe line 94 and the low pressure pipe f
893, a pilot pressure oil is returned to the tank 91 via this valve 96 when the poppet valves 41 and 42 are not operating.

FIG. 2 is a block diagram showing the detailed configuration of the Series III device FF150. Control 1is'! 1lf
f50 is mainly realized by a computer system.

That is, the operating lever position detector 510 detects the position n of the operating lever 62, and the operating signal V1 is input to the A/D.
A/D converter 501 to convert and input interface 5
02, a CPU 503 that processes signals, a ROM 504 that stores various data and control programs, a RAM 505 that stores data, an output interface 506, and a control valve 41 of the electric proportional control valve 40. It consists of a solenoid drive device 507 that drives .42 solenoids 410 and 420.

FIG. 3 is a flowchart showing the processing of the CPU 503 of the above device. The CPU 503 starts execution from step 100. In step 100, initial values of various parameters are set.

In step 102, an operation signal V1 corresponding to the position of the operation lever is input from the operation lever position detector 510.

Next, in step 104, from the operation signal ■1 to the operation lever 6
2 is in the neutral position, and if it is in the neutral position, a command signal @S1 with a duty ratio of 0% is outputted to the solenoid drive unit @507 in step 118. Therefore, from the solenoid drive unit [507, the control signals v2 and v3 are
Since there is no output, the main valve 43 maintains the neutral position.

Next, in step 120, the parameter F is set to 1. F
is a parameter for detecting that the operation lever 62 has changed from the neutral position, and when it is 1, it indicates that it was at the neutral position before the operation.

Next, when the operating lever 62 is operated from the neutral point, it is determined in step 104 that it is not in the neutral position, and the process proceeds to step 106, where the value of F is determined and if it is 1, that is, when the operating lever 62 has changed from the neutral point, At step 108 a timer is set. Then, in step 110, a command signal @S1 with a duty ratio of, for example, 100% is sent to the solenoid drive device 5.
It is output on 07. The Yuito spool 430 moves at high speed. Here, the command signal S1 also includes a signal indicating which solenoid 410 or 420 is to be driven depending on the operating direction of the operating lever 62. Next, in step 112, it is determined that there is a light overload for a certain period of time t1, and if t1 time has elapsed, F is set to O in step 114, and step 102 is carried out.
Return to After step 104, in step 106, N
o That is, the operating lever 62 is not at the neutral point, so step 1
16, a duty ratio command signal @S1 corresponding to the operation signal v1 is output, and the position of the spool 430 of the electric proportional control valve 43 is adjusted according to the position of the operation lever 62, and the hydraulic cylinder 30 The speed of the piston rod 300 is controlled. After this, return to step 102 and
The above process is repeated.

When the operating lever 62 returns to the neutral position, step 102
．． 104.118.120 loop causes spool 4
30 also returns to the neutral position, and the piston rod 300 stops.

4 to 8 show the operating characteristics of the device. The operation signal (1) changes depending on the position IfP of the operation lever 62 (FIGS. 4 and 5). In the steady state, this corresponds to a loop process that passes through step 116, and the duty ratio of the control signal (2) or (3) at this time is proportional to the operation signal (1) (FIG. 7). In a transient state where the operating lever 62 begins to move from the neutral point, steps 106 to 1 are performed.
14, but during time t1, the control signal v
Since the duty ratio of 2 or 3 is set to 100% (FIG. 6), the movement of the spool 430 is fast until time t1 (FIG. 8). In other words, the displacement of the spool is ×1
Since it is driven at high speed until
If tl is set so as to be the dead zone escape point, the dead zone can be escaped at high speed, resulting in high responsiveness.

At the same operating amount of the operating lever 62, the control according to the present invention becomes as shown in curve A in FIG. In the control, this is reached at time t2, and in the conventional control method, it is reached at time t3, and in the end, a correspondence of only Δt is obtained.

Note that the modulation section that modulates the control signals V2 and (3) of the present control device performs steps 106 to 114 in software.
corresponds to the processing section of

Next, a second embodiment will be explained.

In this embodiment, the dead zone escape time t1 is determined based on the oil temperature and the rotational speed of the engine that is the driving source of the pump that pumps the oil. That is, the dead zone of the proportional control valve 40 becomes narrower because the higher the engine rotational speed, the higher the oil pressure and the faster the oil feeding speed. Therefore, the dead zone passage setting time t
1 needs to be made smaller. Also, the higher the oil temperature, the lower the viscosity and therefore the longer the effective dead zone width. Therefore,
It is necessary to increase the dead zone passage setting time t1.

The configuration of the apparatus of this embodiment is shown in FIG. A rotation speed detector 520 that detects the engine rotation speed and a temperature detector 530 that detects the oil temperature are included as part of the dead zone passage time determining section.
This is added to the device of the first embodiment.

FIG. 10 is a flowchart showing the processing of the CPU 503 of the device. The difference from FIG. 3 of the first embodiment is that steps 250 to
This is step 252. Other steps 200 to 220 are steps 100 to 1 in FIG.
Corresponds to 20. In step 250, the rotation speed detector 5
The engine rotation speed is detected from 20, and the oil temperature is detected from temperature detector 530. In step 252, the characteristic diagram shown in FIG. 11 is read from the data map stored in the ROM 504, a dead band passage set time t1 is searched, and the time for setting the duty ratio of the control signal to 100% is varied depending on external conditions. There is.

In the above embodiment, both the engine rotation speed and the oil temperature are considered, but either one may be used.

Further, when the drive source of the oil pump is a battery, the battery voltage E may be detected instead of detecting the rotational speed in the second embodiment and this may be used as a parameter for the dead zone passage setting time. A characteristic diagram of the set time at this time is shown in FIG.

Next, a third embodiment will be described. FIG. 13 is a block diagram showing the configuration of the control device. A displacement detector 540 for detecting the displacement of the spool 430 of the proportional control valve 43 is added to the device of the first embodiment.

FIG. 14 is a flowchart showing the processing of the CPU 503 of the device. The difference from the flowchart in Fig. 3 is that the block in step 3 is
It is 50.352.354. In step 350, the displacement of the spool 430 is detected by the displacement detector 540, and in step 352, it is compared with the dead zone setting position x1. As a result, if the spool 430 exists in the dead zone, the duty ratio of the control signal is set to 100% in step 354. Other steps 300 to 320 correspond to steps 100 to 120 in FIG.

With the above configuration, the spool passes through the dead zone of the proportional control valve at high speed, so that its responsiveness can be improved.

[Effects of the Invention] As explained above, the present invention provides a control device for an electric proportional control valve that controls the amount of movement of the spool based on a control signal indicating the position of the operating lever. This electric proportional control valve control device is characterized in that it includes a modulation section that modulates a control signal so that the spool passes at high speed regardless of the position of the operating lever.

Therefore, the switching speed of the control valve can be improved regardless of the operating layer and operating speed of the operating lever, thereby improving responsiveness and usability to the operating lever of various hydraulic cylinders used in forklifts, etc. I can do it.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing the connection relationship of the device according to the first embodiment of the present invention, FIG. 2 is a configuration diagram showing the configuration of the control device of this embodiment, and FIG. Flowcharts explaining the process, Figures 4, 5, 6, 7, and 8
The figures are characteristic diagrams explaining the operation of the control device and No. 9.
The figure is a block diagram showing the configuration of the second embodiment control device, FIG. 10 is a flowchart showing the processing of the CPU of the same device, and FIGS. 11 and 12 respectively determine the dead zone passage setting time. FIG. 13 is a functional diagram and a mechanical diagram of a 10-diamond proportional control valve showing the configuration of the device of the third embodiment. 30...Hydraulic cylinder 300...Cylinder rond 40...Electric proportional control valve 41.42...Poppet valve

Claims (5)

[Claims] (1) Detect the position of the operating lever, output a control signal corresponding to the position, control the amount of movement of the spool using the control signal, and switch the fluid passage and adjust the flow rate by moving the spool. In a control device for controlling an electric proportional control valve, the position of the operating lever is controlled while the spool passes through a dead zone of the control valve in which the fluid passage is not switched by movement of the spool. Regardless of the above, an electric proportional control valve control device comprising a modulation section that modulates the control signal so as to cause the spool to pass through the spool at a high speed. (2) The electric proportional control valve control device according to claim 1, wherein the period during which the spool passes through the dead zone is determined by time. (3) The control device includes a displacement detector that detects displacement of the spool, and a dead zone detection section that detects that the spool has passed through the dead zone based on the displacement detected by the displacement detector. An electric proportional control valve control device according to claim 1. (4) The control device determines the time period for identifying the dead zone.
Claim 2, further comprising a dead zone passage time determining unit that changes the temperature of the fluid and the rotational speed of an engine that is a drive source of a pump that pumps the fluid. Electric proportional control valve control device. (5) The control device determines the time period for identifying the dead zone.
Claim 2, further comprising a dead zone passage time determining unit that changes the temperature of the fluid and the voltage of a battery that is a driving source of a pump that pumps the fluid. Electric proportional control valve control device.