JP2987306B2 - Hydraulic oil flow control device - Google Patents

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 operated alternately and continuously in an open position for permitting the supply and discharge of hydraulic oil and a closed position for shutting off the supply and discharge of hydraulic oil. The present invention relates to a hydraulic oil flow control device.

[0002]

2. Description of the Related Art In a hydraulic oil 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),
The flow control valve is operated alternately and continuously between the open position and the closed position.The longer the time in the open position of the flow control valve per unit time, the larger the flow rate of the hydraulic oil passing through the flow control valve. Become.

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

[0004]

As described above, when the relational expression between the value of the input command 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. In fact, the above-mentioned relational expressions gradually change. As a result, if the initially set relational expression is used as it is without responding to the change in the relational expression as described above,
Graduation of the duty ratio by recognizing the value of the command current and recognition of the value of the command current for obtaining the desired duty ratio gradually become impossible. SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic oil flow control device that is configured to always accurately grasp a duty ratio and recognize a value of a command current.

[0005]

The feature of the present invention resides in the following constitution in the above-mentioned hydraulic oil flow control device. An electromagnetically operated flow control valve that can be operated alternately and 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 the open and closed positions when an instruction current is input Operating means for outputting to the flow control valve a duty signal that is alternately operated, and corresponding to the value of the command current input to the operating means, the opening operation time and the closing operation time in the duty signal output from the operating means. And changing means for changing the duty ratio of the command current. In a state where the change rate of the value of the indicated current is equal to or less than the set value, the duty signal output from the operating means is fetched, and based on the fetched duty signal, Correction means for correcting the relational expression between the value of the indicated current and the duty ratio of the output duty signal.

[0006]

It is assumed that a certain relational expression is initially set for the input instruction current value and the duty ratio. According to the configuration of the present invention, when the duty ratio changes in accordance with the change in the value of the instruction current in this state, the actual duty signal (duty ratio) output from the operation unit is taken into the correction unit. Go. Thereby, the duty signal (duty ratio) actually output in accordance with the value of the instruction current input to the operation means and the duty signal (duty ratio) obtained from the relational equation set first are corrected. Can be compared.

Accordingly, if the duty signal (duty ratio) actually output matches the duty signal (duty ratio) obtained from the initially set relational expression, the relational expression set first is accurate. It can be determined that it is. Conversely, if the duty signal (duty ratio) actually output is different from the duty signal (duty ratio) obtained from the relational equation set first,
Due to air temperature, hydraulic oil temperature, aging of the flow control valve, etc.
Since it is determined that the relational expression set first does not match the actual state, in such a case, the relational expression is modified by the correcting means based on the above-described actually output duty signal (duty ratio). Will be modified.

In this case, according to the present invention, the rate of change of the value of the command current input to the operating means is equal to or less than the set value, ie,
The actual duty signal (duty ratio) output from the operation means is taken into the correction means when the command current is stable without changing much. If the indicated current is stable,
Since the actual duty signal (duty ratio) corresponding to the command current is small and stable, the actual duty signal (duty ratio) corresponding to the command current can be accurately detected. Thus, the correction of the relational expression based on the actually output duty signal (duty ratio) is performed with high accuracy so as to match the actual state.

[0009]

As described above, in the hydraulic oil flow control device, the relational expression between the value of the input command current and the duty ratio is modified at any time so as to match the actual state. Therefore, regardless of the air temperature, the temperature of the hydraulic oil, the aging of the flow control valve, etc., the duty ratio can be grasped by recognizing the command current value, and the command current value for obtaining the desired duty ratio can be recognized. Can always be performed accurately, so that the control accuracy of the flow rate of the hydraulic oil by the flow control valve can be improved. Then, 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 working oil by the flow 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, and hydraulic oil from a pump (not shown) is supplied to an oil passage 2 and a control valve 3. Via hydraulic cylinder 1
Supply / discharge operation. The control valve 3 is an electromagnetically operated type. The extension position 3U (boom rise) and the contraction position 3D of the hydraulic cylinder 1
(Boom lowering) and the neutral position 3N are operable at three positions, and are biased toward the neutral position 3N by springs.

An oil passage 2 is provided with a flow control valve 4.
The flow control valve 4 is of an electromagnetically operated type, and can be operated to two positions, an open position 4a for allowing the supply of hydraulic oil and a closed position 4b for shutting off the hydraulic oil, and is biased toward the closed position 4b by a spring. An operation lever 5 operated by an operator is provided on a control section of the turntable. An operation position of the operation lever 5 is detected by a potentiometer 6, and the operation position of the operation lever 5 is set as an instruction current I as an operation unit 7 (operation Corresponding to the means).

Next, the hydraulic cylinder 1 using the operating lever 5
The operation of is described. When the operation 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 starts operating from the neutral position N to the ascending position U from the above state, the control valve 3 is operated from the neutral position N to the extended position 3U by the operating 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 control valve 4, and the flow control valve 4 is alternately and continuously operated to the open position 4a and the closed position 4b, so that the operating oil from the pump is released from the control valve. The hydraulic cylinder 1 is supplied to the hydraulic cylinder 1 via an extension 3 and the hydraulic cylinder 1 is extended to operate the boom upward.

As shown in FIG. 2, the duty signal D is obtained by repeatedly outputting an operation signal (a signal for operating the flow control valve 4 to the open position 4a) for each short unit time T of the flow control valve 4. The ratio between 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) is defined as the duty ratio D1. By changing the duty ratio D1, the flow rate of the hydraulic oil passing through the flow control valve 4 can be changed. As the duty ratio D1 increases, the flow rate also increases. Thereby, when the operation lever 5 is operated from the neutral position N to the ascending position U, the larger the operation amount from the neutral position N corresponding to the value of the instruction current I, the larger the operation amount.
The duty ratio D1 is increased and the hydraulic cylinder 1 is configured to extend at a high speed (corresponding to a change unit).

In this case, when an operation signal for operating the control valve 3 from the neutral position 3N to the extension position 3U is output as shown in FIG. 2, the operation signal is first output simultaneously with the duty signal D. In this way, a delay in the operation of the flow control valve 4 is prevented. Conversely, if the operation signal for operating the control lever 5 to return to the neutral position N and operating the control valve 3 from the neutral position 3N to the extended position 3U stops, the operation signal stops and the unit time T of the duty signal D End is set to match.

The above-mentioned state is similarly obtained when the operating lever 5 is operated from the neutral position N to the lowering position D. In this case, the control valve 3 is operated from the neutral position 3N to the contracted position 3D. The flow control valve 4 is alternately and continuously operated between the open position 4a and the closed position 4b. As a result, the hydraulic cylinder 1 contracts and the boom descends.

As shown in FIG. 3, the value of the command current I input to the operation unit 7 and the duty signal D output
The relational expression A with respect to the duty ratio D1 is obtained in advance, and what kind of value of the instruction current I is input to the operation unit 7 will produce what kind of duty ratio D1 of the duty signal D1. Can be grasped by the relational expression A. In this case, if 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 air temperature, temperature of the hydraulic oil, aging of the flow control valve 4, and the like, When the operating lever 5 is operated to a certain position (instruction current I of a certain value), the duty ratio D1 obtained from the relational expression A differs from the actual duty ratio D1, so the relational expression A is corrected. The need arises. Next, the modification of the relational expression A will be described.

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

Next, when the rate of change C of the command current I becomes equal to or less than the set value C1 (step S3) (a state in which the operator stops operating the operation lever 5 or operates the operation lever 5 only very slowly). Then, 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 compared. The oldest memory is deleted (step S5).

Thus, the newly stored instruction current I
As shown in FIG. 3, 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 obtained by the storage of the value of the duty ratio D1 and the remaining storage. It is reset as a function (I = a.D1 + b) (a, b: constant) (step S6) (corresponding to a correction means). As described above, the value of the command 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.

[Alternative Embodiment] 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. The pilot pressure to the 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 the drawings]

FIG. 1 is a circuit diagram of a control valve, a flow control valve, and the like.

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 correcting a relational expression.

[Explanation of symbols]

 4 Flow control valve 4a Flow control valve open position 4b Flow control valve closed position

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F16K 31/00-31/11 F15B 11/04 G05D 7/06

Claims (1)

(57) [Claims] An electromagnetically operated flow control valve (4) operable alternately and continuously in an open position (4a) for permitting supply and discharge of hydraulic oil and a closed position (4b) for shutting off supply and discharge of hydraulic oil. 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 command current (I) is input; An opening operation time (T1) and a closing operation time in the duty signal (D) output from the operating means (7) in accordance with the value of the command current (I) input to the operating means (7). (T2) and a changing means for changing the duty ratio (D1), and the rate of change (C) of the value of the command current (I) is set to a set value (C
1) In the following state, 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) and the output are outputted. A hydraulic oil flow control device comprising correction means for correcting the relational expression (A) between the duty signal (D) and the duty ratio (D1).