JPH08285120A - Hydraulic oil flow rate controller - Google Patents

Abstract

PURPOSE: To improve accuracy for controlling a hydraulic oil flow rate performed by a flow rate control valve by rectifying a relational expression between an input instruction current value and the duty ratio of an output duty signal based on a duty signal fetched from an operating means. CONSTITUTION: When an operation lever 5 is operated from a neutral position N to an up position U side, a control valve 3 is operated from a neutral position 3N to an expansion position 3U by an operation unit 7 based on an instruction current I. Simultaneously, a duty signal D is outputted from operation oil 7 and a flow rate control valve 4 is continuously operated alternately between an open position 4a and a closed position 4b. Hydraulic oil is supplied from a pump to a hydraulic cylinder 1 via the control valve 3 and the hydraulic cylinder 1 is expanded, raising a boom. A relational expression between the value of the input instruction current I and a duty ratio D is corrected so as to coincide with an actual condition when necessary. Thus, accuracy for controlling a hydraulic oil flow rate by the flow rate control valve 4 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an electromagnetically operated flow control valve which can be continuously operated alternately in an open position that allows the supply and discharge of hydraulic oil and a closed position that blocks the supply and discharge of hydraulic oil. The present invention relates to a flow control device for hydraulic oil.

[0002]

2. Description of the Related Art In a hydraulic fluid flow control device using a flow control valve as described above, a duty signal (an operation signal corresponding to an open position and an operation signal corresponding to a closed position are alternately output to the flow control valve. Output signal)
The flow control valve is operated continuously in an open position and a closed position alternately.The longer the flow control valve is in the open position per unit time, the greater the flow rate of hydraulic oil passing through the flow control valve. Become.

Operating means for outputting a duty signal to the flow control valve, and duty of opening operation time and closing operation time in the duty signal output from the operating means, corresponding to the value of the instruction current input to this operating means. A changing unit for changing the ratio is provided, and the duty ratio is changed and the flow rate of the hydraulic oil passing through the flow control valve is changed by automatically or artificially changing the value of the instruction current. In this case, if the relationship between the input instruction current value and the duty ratio is grasped in advance as a relational expression, the duty ratio can be grasped by recognizing the instruction current value. The value of the instruction current for obtaining the desired duty ratio can be recognized.

[0004]

As described above, when the relational expression between the value of the input instruction current and the duty ratio is set in advance, the temperature, the temperature of the hydraulic oil, the secular change of the flow control valve, etc. , The above relational expression actually changes gradually. As a result, if the relational expression set at the beginning is used as it is without responding to the change in the relational expression as described above,
Gradually, it becomes difficult to grasp the duty ratio by recognizing the value of the instruction current and to recognize the value of the instruction current for obtaining the desired duty ratio. It is an object of the present invention to configure a hydraulic oil flow control device so that the duty ratio can be grasped and the value of an instruction current can be recognized accurately at all times.

[0005]

A feature of the present invention resides in that the hydraulic fluid flow rate control device as described above is configured as follows. Electromagnetically-operated flow control valve that can be operated continuously in an open position that allows the supply and discharge of hydraulic oil and a closed position that shuts off the supply and discharge of hydraulic oil, and an open position and a closed position when an instruction current is input Operating means for alternately outputting the duty signal to the flow control valve, and the opening operation time and the closing operation time in the duty signal output from the operating means, corresponding to the value of the instruction current input to the operating means. And a duty signal output from the operating means when the rate of change of the value of the instruction current is equal to or less than the set value, and input based on the loaded duty signal. The correction means for correcting the relational expression between the value of the instruction current and the duty ratio of the output duty signal is provided.

[0006]

It is assumed that a relational expression is first set for the value of the input instruction current and the duty ratio. According to the configuration of the present invention, when the duty ratio is changed according to the change of the value of the instruction current in this state, the actual duty signal (duty ratio) output from the operating means is taken in by the correcting means. Go. Thus, the duty signal (duty ratio) actually output corresponding to the value of the instruction current input to the operating means and the duty signal (duty ratio) obtained from the initially set relational expression are corrected by the correcting means. Can be compared in.

As a result, if the actually output duty signal (duty ratio) and the duty signal (duty ratio) obtained from the initially set relational expression match, the initially set relational expression is accurate. It can be judged that it is a good one. On the contrary, if the duty signal (duty ratio) actually output is different from the duty signal (duty ratio) obtained from the relational expression initially set,
Depending on the temperature, the temperature of hydraulic oil, the secular change of the flow control valve, etc.
Since it is determined that the relational expression initially set does not match the actual state, in such a case, the relational expression is corrected by the correction means based on the duty signal (duty ratio) actually output. Will be fixed.

In this case, according to the present invention, the rate of change of the value of the instruction current input to the operating means is equal to or less than the set value, that is,
The actual duty signal (duty ratio) output from the operating means is configured to be taken in by the correcting means in a state where the instruction current does not change much and is stable. When the instruction current is stable like this,
Since the actual duty signal (duty ratio) corresponding to the instruction current is also small and stable, the actual duty signal (duty ratio) corresponding to the instruction current can be accurately detected. As a result, the relational expression based on the duty signal (duty ratio) actually output is corrected with high accuracy so as to match the actual state.

[0009]

As described above, in the hydraulic oil flow rate control device, the relational expression between the value of the input instruction current and the duty ratio is modified as needed so as to match the actual state. Therefore, the duty ratio can be grasped by recognizing the value of the instruction current regardless of the temperature, the temperature of the hydraulic oil, the secular change of the flow control valve, etc., and the value of the instruction current can be recognized to obtain the desired duty ratio. Therefore, the accuracy of controlling the flow rate of the hydraulic oil by the flow rate control valve can be improved. Since the relational expression is corrected based on the stable actual duty signal (duty ratio) with little change, the control accuracy of the flow rate of the hydraulic oil by the flow rate control valve can be further improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hydraulic cylinder 1 for raising and lowering a boom of a backhoe device provided on a swivel in a backhoe for civil engineering construction, in which hydraulic oil from a pump (not shown) is used as an oil passage 2 and a control valve 3. Through the hydraulic cylinder 1
It is operated to feed and discharge. The control valve 3 is an electromagnetically operated type, and the hydraulic cylinder 1 has an extended position 3U (boom raised) and a retracted position 3D.
(Boom lowering) and the neutral position 3N are operable, and a spring biases the neutral position 3N.

A flow control valve 4 is provided in the oil passage 2.
The flow control valve 4 is of an electromagnetically operated type and can be operated in two positions, an open position 4a that allows the supply of hydraulic oil and a closed position 4b that shuts off the hydraulic oil, and is biased by a spring toward the closed position 4b. An operation lever 5 operated by an operator is provided in the control section of the swivel base, and the operation position of the operation lever 5 is detected by the potentiometer 6, and the operation position of the operation lever 5 is used as an instruction current I as an operation unit 7 (operation Corresponding to the means) has been entered.

Next, the hydraulic cylinder 1 by the operating lever 5
The operation of will be described. When the operating lever 5 is operated to the neutral position N as shown in FIG. 1, the control valve 3 is held at the neutral position 3N, the flow control valve 4 is held at the closed position 4b, and the hydraulic cylinder 1 is stopped. ing. When the operation lever 5 is started to be operated from the neutral position N to the raised position U side from the above state, the control valve 3 is operated from the neutral position N to the extended position 3U by the operation unit 7 based on the instruction current I. At the same time, the duty signal D is output from the operation unit 7 to the flow rate control valve 4, the flow rate control valve 4 is operated alternately in the open position 4a and the closed position 4b, and the hydraulic oil from the pump is controlled by the control valve. It is supplied to the hydraulic cylinder 1 via 3, and the hydraulic cylinder 1 is extended and the boom is raised.

As shown in FIG. 2, as the duty signal D, an operation signal (a signal for operating the flow rate control valve 4 to the open position 4a) is repeatedly output at each short unit time T of the flow rate control valve 4. The duty ratio D1 is the ratio of the output time T1 of the operation signal (corresponding to the opening operation time) and the stop time T2 of the operation signal (corresponding to the closing operation time). By changing the duty ratio D1, the flow rate of the hydraulic oil passing through the flow control valve 4 can be changed, and the flow rate increases as the duty ratio D1 increases. As a result, when the operation lever 5 is operated from the neutral position N to the raised position U side, the operation amount from the neutral position N of the operation lever 5 corresponding to the value of the instruction current I increases,
The duty ratio D1 is increased so that the hydraulic cylinder 1 is extended at a high speed (corresponding to a changing unit).

In this case, when an operation signal for operating the control valve 3 from the neutral position 3N to the extended position 3U is output as shown in FIG. 2, the operation signal is also first output for the duty signal D at the same time. In this way, the delay of the operation of the flow control valve 4 is prevented. On the contrary, when the operation signal for returning the operation lever 5 to the neutral position N to operate the control valve 3 from the neutral position 3N to the extended position 3U is stopped, the operation signal is stopped and the unit time T of the duty signal D It is set to match the end.

The above-described state is similarly performed when the operation lever 5 is operated from the neutral position N to the lowered position D side. In this case, the control valve 3 is operated from the neutral position 3N to the contracted position 3D. The flow rate control valve 4 is alternately and continuously operated in the open position 4a and the closed position 4b. As a result, the hydraulic cylinder 1 contracts and the boom is lowered.

As shown in FIG. 3, the value of the instruction current I inputted to the operation unit 7 and the duty signal D outputted.
The relational expression A with the duty ratio D1 of the flow control valve 4 is obtained in advance, and when what value of the instruction current I is input to the operation unit 7, the duty signal D of what the duty ratio D1 is. The relational expression A can be used to determine whether or not the data is output to. In this case, when the relationship between the value of the input instruction current I and the duty ratio D1 of the output duty signal D changes due to the temperature, the temperature of the hydraulic oil, the secular change of the flow control valve 4, or the like, When the operating lever 5 is operated to a certain position (indicating current I having a certain value), the duty ratio D1 obtained from the relational expression A becomes different from the actual duty ratio D1, so the relational expression A is corrected. The need arises. Next, the correction of the relational expression A will be described.

A plurality of sets of the value of the instruction current I input to the operation unit 7 and the duty ratio D1 of the duty signal D actually output are stored, and based on this storage, as shown in FIG. Relational expression A between the value of the input instruction current I and the duty ratio D1 of the output duty signal D
Is set as a linear function (I = a · D1 + b) (a, b: constant). In the above state, as shown in FIG.
When the operator operates the operation lever 5 to another position while the operation lever 5 is operated to a certain position and the value of the instruction current I changes (step S1), the rate of change C of the instruction current I is changed.
Is detected (step S2).

Next, when the rate of change C of the instruction current I becomes equal to or less than the set value C1 (step S3) (a state in which the operator stops the operation of the operation lever 5 or operates the operation lever 5 only very slowly). ), The value of the instruction current I input at this time and the duty ratio D1 of the duty signal D actually output are newly stored (step S4), and the value of the instruction current I and the duty ratio D1 are stored. The oldest memory is erased (step S5).

As a result, the newly stored instruction current I
By storing the value of the duty ratio D1 and the duty ratio D1 and the rest of the storage, the relational expression A between the value of the input instruction current I and the duty ratio D1 of the output duty signal D is calculated as shown in FIG. It is reset as a function (I = a · D1 + b) (a, b: constant) (step S6) (corresponding to the correction means). As described above, the value of the instruction current I input each time the operating lever 5 is operated once and the duty ratio D1 of the duty signal D actually output are updated, and the relational expression A is reset. Go.

[Other Embodiments] In the above-described embodiment, the flow rate of the hydraulic oil to the hydraulic cylinder 1 is changed by the flow control valve 4. However, in contrast to the hydraulic pilot operated control valve, The pilot pressure to this control valve may be changed by the flow control valve of the present invention.

[0021] In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a control valve, a flow control valve, etc.

FIG. 2 is a diagram showing a duty signal to a flow control valve.

FIG. 3 is a diagram showing a relational expression between an instruction current and a duty ratio of a duty signal.

FIG. 4 is a diagram showing a flow of modifying a relational expression.

[Explanation of symbols]

 4 flow control valve 4a flow control valve open position 4b flow control valve closed position 7 operating means I command current D duty signal D1 duty ratio T1 open operation time T2 close operation time C rate of change of command current C1 set value A relational expression

Claims (1)

[Claims] 1. An electromagnetically operated flow control valve (4) which is alternately and continuously operable in an open position (4a) that allows the supply and discharge of hydraulic oil and a closed position (4b) that blocks the supply and discharge of hydraulic oil. And an operating means (7) for outputting to the flow control valve (4) a duty signal (D) for alternately operating the open position (4a) and the closed position (4b) when the instruction current (I) is input. , The opening operation time (T1) and the closing operation time in the duty signal (D) output from the operation means (7) corresponding to the value of the instruction current (I) input to the operation means (7). (T2) and a changing means for changing the duty ratio (D1), and the rate of change (C) of the value of the instruction current (I) is the set value (C).
1) In the following states, the duty signal (D) output from the operating means (7) is fetched, and based on the fetched duty signal (D), the value of the input instruction current (I) is output. A flow rate control device for hydraulic fluid, comprising: a correction means for correcting the relational expression (A) with the duty ratio (D1) of the duty signal (D).