WO2013176003A1

WO2013176003A1 - Control device for cargo handling

Info

Publication number: WO2013176003A1
Application number: PCT/JP2013/063456
Authority: WO
Inventors: 仁美飯泉; 寧青木; 拓郎岸田
Original assignee: 株式会社島津製作所
Priority date: 2012-05-23
Filing date: 2013-05-14
Publication date: 2013-11-28
Also published as: JP5920461B2; TW201348108A; JPWO2013176003A1; TWI490423B

Abstract

This control device is provided for use in industrial vehicles that are equipped with: a cargo loading platform; an actuator for driving the cargo loading platform; a hydraulic circuit that supplies hydraulic fluid to the actuator and that includes an electromagnetically operated multi-control valve in which the aperture is varied by changing the magnitude of a control current supplied to a solenoid; and an operation unit for receiving an operation to change the aperture of the electromagnetically operated multi-control valve and outputting a signal that indicates the operation amount. The control device at least performs: a control for determining the mean value of the magnitude of the control current corresponding to the aperture of a proportional valve that is the electromagnetically operated multi-control valve, said determination being based on the signal that indicates the operation amount and is output from an operation lever that is the operation unit; a control for determining, with the aperture of the proportional valve as a parameter, the magnitude of the dither current, which is an AC component, that should be added; and a control for outputting the control current to the proportional valve (42), the control current having the AC component of a magnitude determined by the control for determining the magnitude of the AC component using the magnitude determined by the mean value based on the aperture of the proportional valve.

Description

Handling control device

The present invention relates to an industrial vehicle cargo handling control device that is used for cargo handling work and is equipped with a hydraulic circuit including an electromagnetically operated multi-control valve.

Conventionally, in an industrial vehicle that is used for cargo handling work and configured to elevate and lower and tilt the cargo bed connected to the actuator by supplying hydraulic fluid to the actuator via a hydraulic circuit, In order to be able to control the speed of forward and backward tilting, an electromagnetically operated multi-control valve capable of changing the opening degree has been provided in the hydraulic circuit (see, for example, Patent Document 1). By adopting such a hydraulic circuit, it is possible to control the operating speed of the actuator, that is, the speed of raising and lowering the platform and tilting forward and backward, by changing the amount of hydraulic fluid that passes through the electromagnetically operated multi-control valve. Because. Such an electromagnetically operated multi-control valve has a structure in which a spool as a valve element moves in a sleeve connected to an input port and an output port, and the spool is sucked by electromagnetic force generated by energizing the solenoid. And the moving amount of the spool, that is, the opening degree is changed in proportion to the magnitude of the current supplied to the solenoid. In the electromagnetically operated multi-control valve having such a configuration, for the purpose of preventing the sticking of the spool, reducing the hysteresis when moving the spool, or improving the responsiveness when moving the spool, It is widely performed to add an AC component (hereinafter referred to as a dither current) for minutely vibrating the spool to the current supplied to the solenoid.

By the way, the amplitude of the spool due to the dither current is conventionally constant regardless of the amount of movement of the spool, that is, the average value of the current supplied to the solenoid. However, in such a configuration, the vicinity of the maximum current amount at which the opening degree of the electromagnetically operated multi-control valve becomes 0 (hereinafter referred to as a rising portion of the cargo handling flow rate) or an increase in the magnitude of the current is compared. When the magnitude of the current supplied to the solenoid is changed in order to move the spool in the vicinity of the point where the increase in the opening degree of the electromagnetic control type multi-control valve becomes discontinuously large (hereinafter referred to as a cargo handling flow rate changing portion). The spool vibration due to the dither current causes a large change in the cargo handling flow rate, which may cause problems in cargo handling control such as vehicle body vibration.

JP-A-11-171497

The present invention pays attention to the above points, and in an industrial vehicle equipped with an electromagnetically operated multi-control valve that drives a spool using a solenoid, the increase in the opening degree of the electromagnetically operated multi-control valve is discontinuously large. If the magnitude of the current supplied to the solenoid is changed in order to move the spool in the vicinity of the point (hereinafter referred to as a cargo handling flow rate changing portion), the change in the cargo handling flow rate increases due to the spool vibration caused by the dither current. The object is to solve the problem that trouble occurs in cargo handling control such as vibration.

In order to solve such a problem, the cargo handling control device according to the present invention has the following configuration. That is, the cargo handling control device according to the present invention includes a loading platform, an actuator that drives the loading platform, and an electromagnetic operation type in which the opening degree is variable by changing the magnitude of the control current that is supplied to the actuator and supplied to the solenoid. Used in an industrial vehicle comprising a hydraulic circuit including a multi-control valve, and an operation unit that receives an operation for changing the opening of the electromagnetically operated multi-control valve and outputs a signal indicating an operation amount. Control for determining an average value of the control current supplied to the electromagnetically operated multi-control valve based on a signal indicating the operation amount output from the control unit, and the control using the average value of the control current as a parameter Control for determining the magnitude of the AC component to be added to the current, and the AC component at a magnitude determined based on the signal indicating the manipulated variable. It performs control for outputting the control current having the alternating-current component of a magnitude determined by the control for determining the magnitude of the electromagnetic operation type multiplex control valve at least.

If it is such, by reducing the magnitude of the alternating current component, that is, the dither current in the rising part of the cargo handling flow rate and the cargo handling flow rate changing part, the change in the cargo handling flow rate can be suppressed in such a region, Stable cargo handling control is possible.

According to the present invention, the current supplied to the solenoid to slightly vibrate the spool can be arbitrarily selected in order to reduce the hysteresis of the spool and the spool movement amount provided with the electromagnetically operated multi-control valve that drives the spool using the solenoid. In an industrial vehicle to which a dither current having a frequency of 5 is added, the handling control can be stabilized by suppressing the dither current at the rising portion of the cargo handling flow rate and the cargo handling flow rate changing portion.

Schematic of the hydraulic circuit used for the industrial vehicle which concerns on one Embodiment of this invention. The flowchart which shows the procedure of control by the opening degree determination program which concerns on the same embodiment. FIG. 4 is a control current-loading flow characteristic diagram and a control current-dither current amplitude map of a proportional valve according to the embodiment.

Hereinafter, an embodiment of the present invention will be described.

The industrial vehicle 1 of the present embodiment includes an actuator 3 that drives a loading platform 2 on which loads are loaded, a hydraulic circuit 4 as shown in FIG. 1 that supplies hydraulic fluid to the actuator 3, and the hydraulic circuit 4. A control device 5 for controlling the flow rate of the hydraulic fluid supplied to the actuator 3 and an operation lever 61 as an operation portion for receiving an operation for controlling the lifting speed of the cargo bed 2 are provided with a signal to the control device 5. An input unit 6 for output is mounted.

In the present embodiment, the actuator 3 raises the loading platform 2 by receiving the hydraulic fluid supplied to the first cylinder chamber 31 and also receives the rod 33 by receiving the hydraulic fluid supplied to the second cylinder chamber 32. This is a hydraulic actuator 3 that lowers the loading platform 2 through the hydraulic actuator 3. As described above, the actuator 3 is supplied with hydraulic fluid via the hydraulic circuit 4.

The hydraulic circuit 4 is connected to a motor M as a driving source, and supplies a hydraulic pump 41 for supplying hydraulic pressure to the actuator 3, and hydraulic fluid that flows into the actuator 3 through the hydraulic pump 41. In order to store the hydraulic fluid, an electromagnetically operated multi-control valve (hereinafter referred to as a proportional valve 42) that can change the opening degree in response to a control signal from the control device 5 so that the amount can be changed. An input passage 44 connecting the tank 43 to the proportional valve 42 via the hydraulic pump 41, a first output passage 45 connecting the proportional valve 42 and the first cylinder chamber 31, and the proportional The second output passage 46 connecting the valve 42 and the second cylinder chamber 32, the proportional valve 42 and the tank 43 communicate with each other, and discharged from the first or

second cylinder chamber

31, 32. Operation Wherein a discharge passage 47 for returning to the tank 43, and a through-passage 48 for returning the hydraulic fluid the liquid discharged from the pressure pump 41 to the tank 43 with no load.

The proportional valve 42 is in a neutral state in which the input passage 44 and the first and

second output passages

45 and 46 are blocked and the input passage 44 and the through passage 48 are communicated with each other. The ascending state in which the first output passage 45 is communicated with the second output passage 46 and the discharge passage 47, and the input passage 44 and the second output passage 46 are communicated with each other. A descending state in which the first output passage 45 and the discharge passage 47 communicate with each other can be taken. The proportional valve 42 can change the opening degree based on the open / close signal e from the control device 5 in the raised state and the lowered state. The proportional valve 42 has a configuration in which a spool (not shown), which is a valve body, can slide in a sleeve connected to an input port and an output port. The spool is biased to take a neutral state by a spring, and when current is supplied to the solenoid 48, the spool is attracted and lifted against the biasing force of the spring by the electromagnetic force generated in the solenoid 48. State or descending state.

The operation lever 61 of the input unit 6 accepts a selection input as to whether the proportional valve 42 is in the neutral state, the raised state, or the lowered state. More specifically, the operation lever 61 selectively takes any one of a neutral position, a raised position, and a lowered position, and the proportional lever when the operation lever 61 assumes the neutral position, the raised position, and the lowered position, respectively. In order to set the valve 42 to the neutral state, the raised state, and the lowered state, an elevation stop signal a indicating the position of the operation lever 61 is output to the control device 5.

The control device 5 is a control system having a processor, a memory, an input interface, an output interface, and the like. In addition, an elevation stop signal a from the operation lever 61 of the input unit 6 is input to the input interface of the control device 5. On the other hand, an opening / closing signal e for changing the opening degree is output from the output interface of the control device 5 to the proportional valve 42. Further, in a predetermined area of the memory, a control current map indicating a correspondence between the operation amount of the operation lever 61 indicated by the elevation stop signal a and the magnitude of the control current to be supplied to the solenoid 48 is stored. Further, in another predetermined area of the memory, it is executed when the input unit 6 receives an operation for starting the raising / lowering operation, and when the CPU executes it, the raising / lowering stop signal a from the operation lever 61 is received. A program for obtaining and controlling the change of the opening degree of the proportional valve 42 by supplying a current of a magnitude corresponding to the elevation stop signal a to the solenoid 48 of the proportional valve 42 is incorporated.

Here, the program supplies a control current having an average value A having a magnitude corresponding to the operation amount of the operation lever 61 indicated by the elevation stop signal a to the solenoid 48 of the proportional valve 42 and prevents the spool from sticking. For the purpose of reducing hysteresis when moving the spool or improving responsiveness when moving the spool, a dither current for minutely vibrating the spool is added to the current supplied to the solenoid. This is a program for performing control. Therefore, the amplitude V of the dither current is set so as to be smaller than the other regions at the rising portion of the cargo handling flow rate and the cargo handling flow rate changing portion. More specifically, the proportional valve 42 according to the present embodiment has a control current-loading flow characteristic as shown in FIG. That is, when a state below the magnitude rising value A ₁ of the control current in a state above the rising value A _1, hydraulic fluid can pass through the proportional valve 42. In comparison with the state in which the magnitude of the control current is below the cargo flow rate change value A ₂ exceeds the rising value A _1, the magnitude of the control current in a state above the該荷role flow rate change value A _2, the control current The ratio of the increase width of the cargo handling flow rate to the increase width increases. When the average value A of the control current is in the range of the width α centered on the rising value A ₁ , and the average value A of the control current is the width centered on the cargo flow rate change value A _2. When it is in the range of α, control is performed to set the amplitude V of the dither current to a value V ₂ that is smaller than the amplitude V ₁ of the other region. However, when the operation amount of the operation lever 61 is sufficiently small to be considered not to open the valve, in other words, when the average value A of the control current is below the predetermined value A ₀ , the dither current Set the amplitude V to zero.

Hereinafter, the control procedure by the opening degree determination program will be described below with reference to FIG. 2 which is a flowchart.

First, the operation amount of the operation lever 61 is detected (S1), and the average value A of the magnitude of the control current output to the proportional valve 42 is determined using this operation amount as a parameter (S2). Specifically, using the operation amount of the operation lever 61 indicated by the lift stop signal a as a parameter, the average value A of the control current is determined by referring to the control current map. Then, it is determined whether or not the average value A of the control current is below A ₀ (S3). If the average value A of the magnitude of the control current is below the A ₀ sets the amplitude V of the dither current to 0 (S4). At this time, the cargo handling flow rate is 0, that is, the opening degree of the proportional valve 42 is 0. On the other hand, if the average value A of the control current does not fall below A ₀ , whether or not the average value A of the control current is in the range of the width α with the rising value A ₁ as the center. Is determined (S5). If the average value A of the control current is not in the range of the width α centered on the rising value A ₁ , then the average value A of the control current is the width centered on the cargo handling flow change value A _2. It is determined whether it is in the range of α (S6). The average value A of the control current is not in the range of the width α around the rising value A ₁ , and the average value A of the control current is in the range of the width α around the cargo flow change value A ₂ If not, the amplitude V of the dither current is set to the normal amplitude V ₁ (S7). On the other hand, when the average value A of the control current is in the range of the width α with the rising value A ₁ as the center, or the average value A of the control current has a width with the cargo flow rate change value A ₂ as the center. If it is in the range of α, the dither current amplitude V is set to the change amplitude V ₂ smaller than the normal amplitude V ₁ (S8).

As described above, according to the present embodiment, the amplitude V ₂ at the time of change, which is the magnitude of the dither current at the rising portion of the cargo handling flow rate and the cargo handling flow rate changing portion, is the magnitude of the dither current in other cases. By making the amplitude smaller than the normal amplitude V _1, it is possible to solve the problem that in such a region, a change in the cargo handling flow rate is increased due to the spool vibration due to the dither current, and a malfunction occurs in the cargo handling control such as the vehicle body vibration. . In other words, the cargo handling control can be stabilized by suppressing the dither current at the rising portion of the cargo handling flow rate and the cargo handling flow rate changing portion.

Note that the present invention is not limited to the embodiment described above.

For example, the above-described embodiment controls a proportional valve used in a hydraulic circuit for supplying hydraulic pressure to an actuator for raising and lowering a cargo bed. The present invention may be applied to a proportional valve used in a hydraulic circuit for supplying hydraulic pressure to an actuator used in the above. For example, control of a proportional valve used in a hydraulic circuit for supplying hydraulic pressure to an actuator for tilting the loading platform forward and backward, or for supplying hydraulic pressure to an actuator for rotating the loading platform to the left and right The present invention may be applied to.

Other various modifications may be made without departing from the spirit of the present invention.

In order to reduce the hysteresis of the spool and the amount of movement of the spool, which has an electromagnetically operated multi-control valve that drives the spool using a solenoid, a dither current of an arbitrary frequency is added to the current supplied to the solenoid to make the spool vibrate slightly. In the added industrial vehicle, it is possible to stabilize the cargo handling control by suppressing the dither current at the rising portion of the cargo handling flow rate and the cargo handling flow rate changing portion.

2 ... Loading platform 3 ... Actuator 4 ... Hydraulic circuit 42 ... Proportional valve (electromagnetically operated multi-control valve)
5. Control device 61. Operation lever (operation unit)

Claims

A loading platform, an actuator for driving the loading platform, and a hydraulic circuit including an electromagnetically operated multi-control valve whose opening is variable by changing the magnitude of a control current that is supplied to the actuator and supplied to the solenoid. Used for an industrial vehicle including an operation unit that receives an operation for changing an opening degree of the electromagnetically operated multi-control valve and outputs a signal indicating an operation amount;
Control for determining the average value of the control current supplied to the electromagnetically operated multi-control valve based on the signal indicating the operation amount output from the operation unit, and using the average value of the control current as a parameter The control determines the magnitude of the alternating current component to be added to the control current, and the average value is determined by the control that determines the magnitude of the alternating current component at a magnitude determined based on the signal indicating the manipulated variable. A cargo handling control device for an industrial vehicle, characterized in that at least control for outputting the control current having the AC component having a magnitude to an electromagnetically operated multi-control valve is performed.