JPH08232905A - Discharge control device for hydraulic pump - Google Patents

Abstract

PURPOSE: To efficiently use a hydraulic fluid discharged from a hydraulic pump. CONSTITUTION: A discharge control device for a variable displacement pump 2 provided with a control means for controlling the discharge pressure of the variable displacement pump 2 for supplying a hydraulic fluid O to an actuator 4, is provided with a flow detecting means 6 for detecting the actuator 4 flow rate actually flowing to the actuator 4, and a target flow arithmatically operating unit 7 for controlling the discharge of the variable displacement pump 2 so that the discharge becomes nearly equal to the actuator 4 flow rate detected by the flow detecting means 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge amount control device for a hydraulic pump applied to a hydraulically driven machine such as a hydraulic excavator.

[0002]

2. Description of the Related Art Hydraulic excavators, bulldozers, etc. are equipped with hydraulic pumps, and working members such as various arms are supplied through the actuators such as hydraulic cylinders by the discharge flow of hydraulic oil discharged by the drive of the hydraulic pumps. Is working. As a method of controlling such a hydraulic system, there are a positive control method and a negative control method.

In the positive control system, the discharge amount of the hydraulic pump is changed according to the operation amount of the operating lever, and when the operation amount is large, the discharge amount from the hydraulic pump increases accordingly. On the contrary, when the operation amount becomes smaller, the ejection amount becomes smaller accordingly. Therefore, the driver can make the operation speed of the actuator desired by operating the operation lever while visually observing the actual operation speed of the arm or the like. Such a positive control method is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-272461.

In the negative control system, a throttle valve is provided in the surplus passage, the downstream side of the throttle valve is connected to an oil tank, and the amount of hydraulic oil that has passed through the surplus passage through the throttle valve, that is, the actuator is provided. The amount of hydraulic oil that has not been delivered is detected, and the pump discharge flow rate is determined so that the pump discharge flow rate decreases with respect to this increase in the excess flow rate.

With this configuration, when the flow rate of the hydraulic oil sent to the actuator is increased by operating the operation lever, the surplus flow rate decreases and the pressure on the upstream side of the throttle valve decreases. A decrease in pressure is detected, a control signal for increasing the discharge amount of the hydraulic pump is transmitted to the hydraulic pump, and the discharge amount of the hydraulic pump increases. When the amount of hydraulic oil sent to the actuator is reduced, the discharge amount of the hydraulic pump is reduced by the action opposite to the above.

[0006]

In the above positive control system, the discharge amount of the hydraulic pump is set only by the operation amount of the operation lever, but the actuator is operated by the load variation of the hydraulic actuator. There is an imbalance between the required flow rate of hydraulic oil and the discharge flow rate of the hydraulic pump, resulting in a wasteful flow rate or conversely the required flow rate cannot be obtained, and energy efficiency declines. In the worst case, there was a problem that a surge phenomenon occurred and the operability deteriorated.

Further, since the above-mentioned negative control method is a method of utilizing the flow rate information of the excess hydraulic fluid that has not been sent to the actuator, it is necessary to secure a surplus flow rate above a certain level, and the hydraulic fluid discharged by the hydraulic pump is required. Many of them are not used to operate the actuator, and have a problem of low energy efficiency.

The present invention has been made in order to solve the above problems, and operates the actuator without any trouble in a state where efficient use of the hydraulic oil discharged from the hydraulic pump is ensured. It is an object of the present invention to provide a discharge amount control device for a hydraulic pump.

[0009]

According to a first aspect of the present invention, there is provided a hydraulic pump discharge amount control device including a control means for controlling a discharge pressure of a hydraulic pump for supplying hydraulic oil to an actuator. Of the discharge amount control device of
A flow rate detecting means for detecting an actuator flow rate actually flowing through the actuator; and a discharge rate controlling means for controlling the discharge rate of the hydraulic pump so as to be substantially equal to the actuator flow rate detected by the flow rate detecting means. It is a feature.

According to a second aspect of the present invention, there is provided a hydraulic pump discharge rate control device according to the first aspect of the present invention, wherein the value of the actuator flow rate detected by the flow rate detecting means is smoothed. In addition, a target flow rate calculation unit for calculating a target flow rate by stacking a minute amount on the target flow rate calculation unit is provided, and the discharge amount of the hydraulic pump is controlled to be the target flow rate. Is.

According to a third aspect of the present invention, there is provided a hydraulic pump discharge amount control device comprising a control means for controlling the discharge pressure of each actuator of a hydraulic pump which is shared for supplying hydraulic oil to a plurality of actuators. And a plurality of flow rate detecting means for detecting the flow rate of each actuator actually flowing in each actuator, and the discharge rate of the hydraulic pump based on the flow rate detection value detected by the flow rate detecting means. And a discharge amount control means for controlling the above.

According to a fourth aspect of the present invention, there is provided a hydraulic pump discharge rate control device according to the third aspect of the hydraulic pump discharge rate control method, wherein the values of the respective actuator flow rates detected by the plurality of flow rate detecting means are set. Smoothed, and
It is characterized in that a target flow rate calculation unit for calculating a target flow rate by adding a small amount to these is provided, and the discharge rate of the hydraulic pump is controlled to be the total value of the target flow rates. It is what

According to a fifth aspect of the present invention, there is provided a hydraulic pump discharge rate control device for obtaining a desired actuator flow rate according to a manipulated variable in the hydraulic pump discharge rate control device according to the second or fourth aspect. Operation means for outputting the required target flow rate signal is provided, and the target flow rate calculation unit is configured to output a target flow rate signal corresponding to the actuator flow rate detected by the flow rate detection means. A target flow rate selection calculation unit for selecting one of the request target flow rate signal and the target flow rate signal and inputting to the hydraulic pump by determining whether or not the value is sufficiently close to the value of the request target flow rate signal. Is provided.

According to a sixth aspect of the present invention, there is provided a hydraulic pump discharge rate control device according to the fifth aspect, wherein the signal output to the hydraulic pump is a required target flow rate signal. And a switching control means for switching from one of the target flow rate signals to the other so as to gradually increase or gradually decrease from the value of one signal toward the value of the other signal. It is characterized by that.

[0015]

According to the discharge amount control device of the hydraulic pump of the above-mentioned claim 1, the discharge amount of the hydraulic pump which is detected by the flow rate detecting means for detecting the flow rate of the actuator actually flowing in the actuator is detected by the flow rate detecting means. Since the discharge amount control means for controlling the flow rate to the actuator is provided, the hydraulic pump discharges in proportion to the flow rate of the working oil actually supplied to the actuator by the pressure control. As a result, the working oil actually required by the actuator is supplied, and the amount of surplus hydraulic oil is reduced.

According to the discharge amount control device of the hydraulic pump of the second aspect, since the value of the actuator flow rate detected by the flow rate detecting means is smoothed by the target flow rate calculating section, it is detected by the normal flow rate detecting means. The obtained raw value slightly fluctuates over time, but such a variation is eliminated, and stable feedback control can be performed. Further, since a signal of the target flow rate in which a further small amount is added to the smoothed value is input to the hydraulic pump, the minimum excess hydraulic oil necessary for oil amount balance is secured by this addition.

According to the discharge amount control device of the hydraulic pump of the third aspect, a plurality of flow rate detecting means for detecting the flow rate of each actuator actually flowing in each of the plurality of actuators, and the detection of the flow rate detecting means. Since the discharge amount control means for controlling the discharge amount of the hydraulic pump based on the detected flow rate value is provided, the discharge amount control means performs a predetermined control based on the flow rate detected value of each flow rate detecting means. Control the discharge rate of the pump to an appropriate value.

Among the plurality of actuators, there are an actuator for performing pressure control, an actuator for which the valve opening is determined by the operation amount of the lever, and an actuator for which the valve opening is determined by the flow rate command signal from the host controller. Even when they are mixed, the discharge amount control means detects the flow rate of the discharge amount of the hydraulic pump for the latter two by detecting the flow rate by providing the flow rate detecting means like the actuator for pressure control. Since the total discharge amount of the pump is controlled, for the actuators for which the pressure control is performed, the hydraulic oil is discharged substantially in proportion to the total flow rate of the working oil supplied to those actuators.

According to the discharge rate control device of the hydraulic pump of the above-mentioned claim 4, since the values of the respective actuator flow rates detected by the flow rate detecting means are smoothed by the target flow rate calculating section, the normal flow rate detecting means is provided. Although the raw value detected by the method slightly fluctuates over time, such a fluctuation can be eliminated and stable feedback control can be performed. Further, since a signal of the target flow rate in which a further small amount is added to the smoothed value is input to the hydraulic pump, the minimum excess hydraulic oil necessary for oil amount balance is secured by this addition.

According to the discharge amount control device of the hydraulic pump of the fifth aspect, the operating means for outputting the required target flow rate signal for obtaining the desired actuator flow rate according to the operation amount is provided, and the target flow rate calculation is performed. The unit is configured to output a target flow rate signal corresponding to the actuator flow rate detected by the flow rate detecting means, and determines whether the value of the target flow rate signal is sufficiently close to the value of the required target flow rate signal. Since the target flow rate selection calculation unit for selecting one of the required target flow rate signal and the target flow rate signal by discrimination and inputting it to the hydraulic pump is provided, the value (Qd) of the required target flow rate signal is used. When a value obtained by subtracting the value (Qi) of the target flow rate signal is equal to or smaller than a predetermined threshold value (Qlim) which is a sufficiently close value set in advance (Q
d-Qi ≦ Qlim), that is, when the operation unit is performing a normal operation, the target flow rate selection calculation unit selects the required target flow rate signal (Qd) output from the operation unit, and thereby the hydraulic pressure is set. Since the working oil is discharged from the pump to operate the actuator, the operation in which the intention of the driver who operates the operating means is reflected is realized.

On the other hand, when Qd-Qi> Qlim, that is, when the operating means is suddenly operated, the target flow rate selection calculation unit automatically obtains the target flow rate signal obtained by the pressure control of the system. Since (Qi) is selected, the working oil is discharged from the hydraulic pump, so that temporary excessive discharge from the hydraulic pump is suppressed.

According to the discharge amount control device of the hydraulic pump of the sixth aspect, the signal output to the hydraulic pump is switched from one of the required target flow rate signal and the target flow rate signal to the other. In this case, since the switching control means switches the value of one signal so as to gradually increase or gradually decrease toward the value of the other signal, it is possible to avoid a sudden change in the discharge amount of the hydraulic pump. To be done.

[0023]

1 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a first embodiment of the present invention is applied. As shown in this figure,
The integrated hydraulic system 1 is a hydraulic system 10 connected by thick solid arrows.
And a control system 50 connected by a broken line. The hydraulic system 10 is a system that circulates hydraulic oil in the system to cause the actuator 4 to perform a predetermined operation, and the control system 50 appropriately sends and receives electrical signals and calculates the state of hydraulic oil. It is a system to control. In the drawing,
The elements forming the hydraulic system 10 are surrounded by a rectangle, and the elements forming the control system 50 are surrounded by a diamond to distinguish the two.

The hydraulic system 10 sucks up hydraulic oil 0 from the oil tank T and pumps hydraulic oil 01 at a predetermined flow rate.
As a variable displacement pump (hydraulic pump) 2, pressure control means 3 for adjusting the pump discharge hydraulic oil 01 to an instructed pressure, and pressure adjusted operation controlled to a predetermined pressure by the pressure control means 3. The actuator 4 is configured to receive and drive the oil 02. The actuator 4 is connected to a working member 40 such as an arm which actually performs a predetermined work by driving the actuator 4.

In the pressure control means 3, the pump discharge hydraulic oil 01 sent from the variable displacement pump 2 at a predetermined flow rate is pressure-adjusted so that the surplus hydraulic oil 03 is discharged to the oil tank T. ing. Further, the hydraulic oil after performing a predetermined work with the actuator 4 is returned to the oil tank T as the return hydraulic oil 04. Although three oil tanks T are drawn in FIG. 1 for the purpose of drawing, they are the same.

In this embodiment, a swash plate type piston pump is used as the variable displacement pump 2.
It is not limited to the swash plate type piston pump as long as it is a displacement type and the capacity can be changed, and other types such as an unbalanced vane pump can also be applied. Further, the pressure control means 3 uses a flow control valve, a directional control valve, or the like, and is formed by a known predetermined hydraulic circuit in which these are variously coupled. In this embodiment, a directional control valve is applied to the pressure control means 3. Further, as the actuator 4, a hydraulic cylinder or a hydraulic motor is applied.

On the other hand, the above-mentioned control system (discharge amount control means) 5
Reference numeral 0 is composed of a flow rate detecting means 6, a target flow rate calculating section 7, and an operating lever (operating means) 8. The flow rate detecting means 6 is pressure-adjusted in the variable displacement pump 2, and the pressure-adjusted hydraulic oil 0 is led to the actuator 4.
The flow rate of 2, that is, the actuator flow rate is detected as an actuator flow rate signal S1 and is detected as a flow rate output signal S2.
The target flow rate calculation unit 7 is based on the flow rate output signal S2, and the flow rate detection means 6 is added every second.
Is for smoothing the actuator flow rate detected by the controller to calculate a predetermined target flow rate that can represent a substantially actuator flow rate, and for outputting the target flow rate signal S3 as the calculation result to the variable displacement pump 2. Is for inputting the pressure command signal S4 corresponding to the manipulated variable to the pressure control means 3.

That is, when the driver operates the operation lever 8, this operation amount is electrically converted into the pressure command signal S4 and input to the pressure control means 3. In the case of comprehensively controlling the entire device including the operation of the operation lever 8, a host control device for automatically controlling the entire device is provided. A pressure command signal S4 equivalent to that output by operating the operation lever 8 is output. Then, in the pressure control means 3, the pressure command signal S4
The directional control valve of the internal hydraulic circuit is opened and closed according to
As a result, the pump discharge hydraulic oil 01 discharged from the variable displacement pump 2 becomes the pressure-adjusted hydraulic oil 02 having a pressure proportional to the operation amount of the operation lever 8 and becomes the actuator 4
To drive the actuator 4.

The surplus hydraulic oil 03 which is no longer needed in the above pressure control and the return hydraulic oil 04 which has been used up by the actuator 4 are returned to the oil tank T and are circulated and used as the hydraulic oil 0 pumped up by the variable displacement pump 2. It

On the other hand, the flow rate detecting means 6 is the pressure controlling means 3
Pressure-adjusted hydraulic oil obtained as a result of pressure control in
Of the actuator, that is, the momentarily changing actuator flow rate, is detected as an actuator flow rate signal S1, converted into an electric signal as a flow rate output signal S2, and this flow rate output signal S2 is output to the target flow rate calculation unit 7. .

The target flow rate calculation unit 7 to which the flow rate output signal S2 is input performs a predetermined smoothing calculation, and as a result, the change over time in the actuator flow rate is removed, and the actual pressure is adjusted on average. A target flow rate signal S3 that substantially matches the flow rate of the hydraulic oil 02 is formed, and this target flow rate signal S3 is input to the variable displacement pump 2 as a control signal (target flow rate signal S3).

Then, the variable displacement pump 2 changes its capacity in accordance with the target flow rate signal S3, and the pump discharge hydraulic oil 01 of an amount substantially corresponding to the actuator flow rate signal S1 actually supplied to the actuator 4 is supplied to the pressure control means 3. Will be discharged toward.

In this embodiment, as a result of the pressure control performed by the feedback control as described above, the pump discharge hydraulic oil 01 of an amount corresponding to the value of the actuator flow signal S1 actually discharged to the actuator 4 is obtained. Is supplied to the pressure control means 3 from the variable displacement pump 2, and therefore the surplus hydraulic oil 03 which is the difference between the flow rate of the pump discharge hydraulic oil 01 and the flow rate of the pressure adjusted hydraulic oil 02 (the value of the actuator flow signal S1). Is extremely small,
The energy loss of the variable displacement pump 2 can be suppressed to the minimum.

Moreover, since the pressure of the pressure-adjusted hydraulic oil 02 set by the operation of the operation lever 8 is reliably ensured, the operating speed of the actuator 4 does not change,
It is driven at a predetermined speed set in advance.

Next, the specific configurations of the pressure control means 3 and the flow rate detection means 6 of the first embodiment will be described with reference to FIG. FIG. 2 is a block diagram for explaining the pressure control means and the flow rate detection means of the first embodiment.

As shown in this figure, the pressure control means 3
Is a directional control valve 31, a valve movable part 31b attached to the directional control valve 31, a downstream pressure gauge 6b provided on the downstream side of the directional control valve 31, a valve opening detection means 31c, and an input. Based on the downstream pressure detection signal S9 and the pressure command signal S4, the control calculation unit 32 that performs the pressure adjustment calculation of the pressure-adjusted hydraulic oil 02, and the output from the control calculation unit 32 is used as the control signal for feedback control. An amplifier 33 for converting and an electromagnetic proportional pressure reducing valve 34 for outputting instrumentation hydraulic pressure to the valve moving part 31b.
It consists of and.

The directional control valve 31 has a spool 31a which is operated by driving the valve movable portion 31b.
A plurality of passages are formed in the spool 31a,
By changing the setting position of the spool 31a variously, the switching of the flow path and the opening area of the passage can be changed. Then, the pressure loss is changed by changing the opening area, the pressure of the hydraulic oil 0 derived from the directional control valve 31 is adjusted, and the hydraulic oil 0 (pressure-adjusted hydraulic oil 02) having a predetermined pressure is obtained. It has become. The valve movable portion 31b is positioned at a position where the pilot pressure of the pilot oil 05 from the electromagnetic proportional pressure reducing valve 34 and the urging force of the spring inside the valve are balanced.

A passage for guiding the excess hydraulic oil 03 to the oil tank T is provided on the upstream side of the direction control valve 31, and a control valve portion 35 is provided in this passage. In the control valve portion 35, various valves such as a control valve and a relief valve are arranged at appropriate places in a predetermined flow path configuration, and when the pressure of the pump discharge hydraulic oil 01 becomes equal to or higher than a set pressure. The valve is configured to open.

Therefore, when the pump discharge hydraulic oil 01 having a constant flow rate is sent from the variable displacement pump 2 toward the directional control valve 31, a pressure loss occurs due to the adjustment of the opening degree of the valve of the directional control valve 31, and the downstream of the downstream. The hydraulic oil 0 becomes the pressure-adjusted hydraulic oil 02 having a desired pressure, but the flow rate is the pump discharge hydraulic oil 01.
Less than that. Then, the subtraction between the pump discharge hydraulic oil 01 and the pressure-adjusted hydraulic oil 02 becomes the surplus hydraulic oil 03, which is led out to the oil tank T via the control valve portion 35.

The control arithmetic unit 32 is composed of a comparison arithmetic circuit. The control calculation unit 32 includes an operation lever 8
The pressure command signal S4 proportional to the operation amount generated by operating the
The downstream pressure detection signal S9 indicating the actual pressure value of the pressure-adjusted hydraulic oil 02 detected by is input and comparison calculation is performed between them. The result of this comparison operation,
A deviation between the value of the pressure command signal S4 and the actually detected value of the downstream side pressure detection signal S9 is calculated, and this is input to the amplifier 33 as the deviation signal S5.

The amplifier 33 is a device for pressure feedback control, and outputs a valve displacement command signal S6 toward the electromagnetic proportional pressure reducing valve 34 according to the deviation signal S5. Then, the value of the deviation signal S5 is referred to the value of the valve opening signal S7 indicating the currently set valve opening detected by the valve opening detection means 31c, and is output as the valve displacement command signal S6. To be done. This valve displacement command signal S6
Is output as a current having an amperage value obtained by using a deviation value between the value of the pressure command signal S4 and the actually detected value of the downstream pressure detection signal S9.

Specifically, when the value of the pressure command signal S4 is larger than the value of the downstream pressure detection signal S9, the valve opening of the directional control valve 31 is increased by an amount proportional to the deviation value. When such a valve displacement command signal S6 is output and the value of the pressure command signal S4 is smaller than the value of the downstream pressure detection signal S9, the valve of the directional control valve 31 is moved by an amount proportional to the deviation value. A valve displacement command signal S6 for reducing the opening is output.

The electromagnetic proportional pressure reducing valve 34 is a device for applying a pressure proportional to the strength of the current to the pilot oil 05 by the valve displacement command signal S6 which is a current signal. Since the pilot oil 05 is supplied to the valve movable portion 31b, the valve movable portion 31b operates according to the pressure of the pilot oil 05, and the opening degree of the valve of the directional control valve 31 is set. Of. By such feedback control, the hydraulic oil 0 constantly drawn from the directional control valve 31 is pressure-adjusted hydraulic oil 02 proportional to the operation amount of the operation lever 8.
It has become.

As shown in FIG. 2, the flow rate detecting means 6 includes an upstream pressure gauge 6a provided on the inlet side immediately before the directional control valve 31 and a downstream side pressure gauge provided on the outlet side of the directional control valve 31. The pressure gauge 6b and a flow rate calculator 60 that calculates the actuator flow rate Qid based on the signal values detected by the pressure gauge 6b are included.

The flow rate calculation unit 60 then detects the upstream pressure detection signal S8 detected by the upstream pressure gauge 6a, the downstream pressure detection signal S9 detected by the downstream pressure gauge 6b, and the valve opening degree detection means 31c. The flow rate of the hydraulic oil 0 passing through the directional control valve 31, that is, the actuator flow rate Qid is calculated based on the valve opening signal S7 detected by.

Then, the actuator flow rate (Qid)
The value of is calculated by the following calculation formula.

Qid = Kpq × S (x) × √ (Pi−Po), where Pi: pressure on the inlet side of the directional control valve 31 (value of the downstream pressure detection signal S9) Po: directional control valve 31 On the outlet side (value of upstream pressure detection signal S8) x: Valve opening (value of valve opening signal S7) S (x): Valve opening area determined by x Kpq: Proportional constant Flow rate calculator 60 In the above, each time the upstream side pressure detection signal S8, the downstream side pressure detection signal S9 and the valve opening degree signal S7 are input, the calculation by the above-mentioned calculation formula is performed. The calculated actuator flow rate (Qid) value may be output as it is to the variable displacement pump 2 as a control signal (flow rate output signal S2), but the actuator flow rate (Qid) value oscillates randomly with time. Therefore, when the signal as it is is input to the variable displacement pump 2, the variable displacement pump 2 sends out the hydraulic oil 0 in a finely vibrated state to further promote the vibration, and the whole system vibrates greatly. Inconvenience may occur.

Therefore, in order to eliminate such an inconvenience, in this embodiment, the smoothing process of the control signal as shown in FIG. 3 is performed. FIG. 3 is a block diagram showing the flow rate calculation unit 60 and the target flow rate calculation unit 7 of the flow rate detection means 6. As shown in this figure, the flow rate calculation unit 60 has a valve opening signal S7 (x) and an upstream pressure detection signal S8 (Pi).
And the downstream pressure detection signal S9 (Po) are input, and the actuator flow rate (Qid) is calculated by the above equation.

This flow rate calculation unit 60 calculates the values one by one (Q
The value of (id) is input to the target flow rate calculation unit 7 every time the calculation is performed, and the smoothing process and the stacking process are performed. To this end, the target flow rate calculation unit 7 is provided with a smoothing processing unit 71 that performs the above-described smoothing process, and an overlaying processing unit 72 that overlays a further smaller amount on the smoothed value.

The actuator flow rate (Qid) calculated momentarily by the flow rate calculation section 60 is smoothed by the smoothing processing section 71 of the target flow rate calculation section 7 to remove fine fluctuations, and the smoothed value is further added. A small amount of superposition is performed in the superposition processing unit 72, and then the target flow rate signal S3 is output to the variable displacement pump 2 shown in FIG.

In the smoothing processing of the actuator flow rate (Qid) in the smoothing processing section 71, for example, a time averaging method which adopts an average value of detected values over time, which is traced back a certain time from the present time to the past, or a condenser is used. A filter method or the like for smoothing the raw detection value is applied to the filter.

The superposition processing section 72 is composed of a circuit for superposing a small amount on the smoothed actuator flow rate (Qid). Specifically, a constant value addition method that adds a predetermined constant to the value of the smoothed actuator flow rate (Qid), or a constant value (a value larger than 1 and set to 1 as much as possible) to the value of the smoothed actuator flow rate (Qid). A constant value multiplication method of multiplying by a close number, such as 1.05, is adopted. The reason why the above-mentioned stacking processing section 72 is provided is as follows.

That is, when the target flow rate signal S3 such that the flow rate of the pump discharge hydraulic oil 01 is smaller than the flow rate of the pressure adjusted hydraulic oil 02 is output to the variable displacement pump 2, the desired actuator flow rate is obtained. This is because (Qid) cannot be obtained, and as a result, the pressure of the pressure-adjusted hydraulic oil 02 decreases, and the entire system cannot be properly controlled. If necessary, it is necessary to prevent the required pump discharge flow rate from falling below the current flow rate (the total flow rate when there are multiple actuators). This can be caused by recognizing the flow rate as smaller than it really is due to the effect of liquefaction. In particular, in leveling, when a first-order lag filter is used, when the measurement signal tends to increase, the flow rate is recognized to be smaller than it actually is.

On the other hand, even if the flow rate of the pump discharge hydraulic oil 01 becomes slightly higher than the flow rate of the pressure-adjusted hydraulic oil 02, a large amount is only discharged as the surplus hydraulic oil 03, and the system pressure is increased. Since there is no particular problem in control, the above-mentioned stacking processing is performed by the stacking processing section 72.

However, the integrated hydraulic system 1 of the present invention is shown in FIG.
As shown in, the pump discharge hydraulic oil 0 supplied from the variable displacement pump 2 to the directional control valve 31 whose valve opening is controlled
The directional control valve 31 is returned to the oil tank T as a part of the excess hydraulic oil 03 through the control valve portion 35.
Since the pressure control is performed on the assumption that the pressure of the hydraulic oil 0 (pressure-adjusted hydraulic oil 02) derived from is set to a desired value, the flow rate of the pump discharge hydraulic oil 01 is usually the pressure-adjusted hydraulic oil 02. Target flow rate signal S that is extremely smaller than the flow rate of
3 is not output to the variable displacement pump 2.

Next, the control of the variable displacement pump 2 will be described. FIG. 4 is a block diagram showing a control system of the variable displacement pump. As shown in this figure, the variable displacement pump 2 is formed by attaching a control unit 22 to a swash plate type piston pump 21. The swash plate type piston pump 21
Is a tilt angle displacement mechanism 21 for changing the tilt angle of the pump body 21a and a swash plate (not shown) installed in the pump body 21a.
b and. And this tilt angle displacement mechanism 2
A control signal is input to the 1b from the control unit 22, and the capacity of the swash plate type piston pump 21 is adjusted.

The controller 22 calculates the pump tilt angle target value (Dr) based on the input target flow rate signal S3 and engine speed signal S10.
And a feedback control amplifier 24 for realizing the pump tilt angle target value (Dr).

A value of the pump discharge rate (Qr) corresponding to the smoothed and accumulated actuator flow rate (Qid) is transmitted to the tilt angle calculation section 23 by the target flow rate signal S3, and the engine is driven by the engine. Rotation speed (E
s) is transmitted by the engine speed signal S10, where the pump tilt angle target value (D
r) is calculated.

Dr = k × Qr / Es ……………………, where k is a proportional constant, and a signal loop for feedback control is formed between the amplifier 24 and the tilt angle displacement mechanism 21b. By driving the tilt angle displacement mechanism 21b, the actual tilt angle of the swash plate in the pump body 21a becomes the pump tilt angle target value (Dr) calculated by the tilt angle calculator 23. Therefore, the flow rate detecting means 6 is driven by driving the pump body 21a.
Slightly higher than the actuator flow rate (Qid) detected by
r)) is discharged from the pump body 21a toward the directional control valve 31.

FIG. 5 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a second embodiment of the present invention is applied. The control system of this embodiment is basically the same as that of the first embodiment, but a plurality of first actuators 41,
4n are provided, each of which is a second actuator 42 ... Nth actuator 4n. Each of the actuators 41, 42 ...
A first directional control valve 311 corresponding to 2 ... 4n, a second directional control valve 312 ... An nth directional control valve 31n are provided.

4n is provided with a first working member 401, a second working member 402, ... An nth working member 40n corresponding to each of the actuators 41, 42, ... 4n. Is generally used to indicate either of the above, the same applies hereinafter), and is operated independently of other working members by operating the operating lever 8i.

The hydraulic oil 0 discharged from the variable displacement pump 2 (pump hydraulic oil 01) is pressure control means 3 '.
The first pump discharge hydraulic oil 011, the second pump discharge hydraulic oil 012 ... The nth pump discharge hydraulic oil 01n are supplied to the corresponding directional control valves 31i. Inside the pressure control means 3 ', a passage for extracting the excess hydraulic oil 03 is provided before the pump discharge hydraulic oil 01 branches into each pump discharge hydraulic oil 01i, and a control valve portion 35 is provided in this passage, and a control valve portion is provided. The surplus hydraulic oil 03 that has passed through 35 is discharged to the oil tank T.

Further, in the control system 50 ', an operating lever having a plurality of first operating levers 81, second operating levers 82 ... Nth operating levers 8n corresponding to the respective pressure control means 311, 312 ... 31n. 8'is provided, and the operation amount of each operation lever 8i is the pressure command signal S4i.
Is input to the corresponding directional control valve 31i.

Further, in the control system 50 ', there is provided a flow rate detecting section 6'having a first flow rate detecting means 61, a second flow rate detecting means 62 ... An nth flow rate detecting means 6n corresponding to each directional control valve 31i. The flow rate detecting means 6i in the flow rate detecting section 6'is adapted to detect the actuator flow rate of each directional control valve 31i. Then, the pressure-adjusted hydraulic oil 02i set to a predetermined pressure based on the operation amount of the operation lever 8i by each directional control valve 31i is discharged from each directional control valve 31i.

In order to do so, in the pressure control means 3 ', for each directional control valve 31i, a valve movable portion 31b, a valve opening degree detection means 31c, a control calculation portion 32, an amplifier 33 as shown in FIG. And an electromagnetic proportional pressure reducing valve 34, and
In order to detect each flow rate corresponding to each pressure adjusted hydraulic oil 02i as the first actuator flow rate signal S11, the second actuator flow rate signal S12, ... The nth actuator flow rate signal S1n, the upstream pressure as shown in FIG. 6a in total
And a downstream pressure gauge 6b are provided, but they are not shown in FIG.

In the present embodiment, the actuator flow rates detected by the flow rate detecting means 6i are input to the target flow rate calculating section 7'as the flow rate output signal S2i and added there, and the addition result is obtained. The total target flow rate signal S3 'is input to the variable displacement pump 2. Therefore, the total amount of hydraulic oil 0 for each pressure control means 311, 312, ... 31n is discharged from the variable displacement pump 2.

FIG. 6 is a block diagram showing the internal structure of the target flow rate calculation unit 7 '. As shown in this figure, the target flow rate calculating section 7'is provided with a first flow rate output signal S21, a second flow rate output signal S22 ... An nth flow rate output signal S2n which are input from the flow rate detecting section 6 '. 1 smoothing processing unit 7
11, second smoothing processing unit 712 ... Nth smoothing processing unit 71
n, the smoothing processing units 711, which perform predetermined overlaying on the smoothed signals output from these smoothing processing units
712 ... 71n are provided with a first top stacking processing section 721, a second top stacking processing section 722 ... an nth top stacking processing section 72n.

The functions of the i-th smoothing processing unit 71i and the i-th upper stacking processing unit 72i are the same as those of the smoothing processing unit 71 and the upper stacking processing unit 72 described above with reference to FIG. .

Then, each of these stacking processing units 721, 7
The output signals from 22 ... 72n are summed in the adder 73, and the value of the flow rate of the hydraulic oil 0 not used for operating the actuator 4i calculated in the surplus flow rate calculator 74 is added to obtain the target flow rate signal. The control unit 22 outputs as S3 '. In addition, the hydraulic oil not used above 0
Flow rate of all directional control valves 311, 312 ... 31n
Is the minimum flow rate of the hydraulic oil 0 discharged from the variable displacement pump 2, which is the flow rate returned to the oil tank T as the excess hydraulic oil 03 when is closed.

In the surplus flow rate calculation unit 74, the minimum flow rate is appropriately calculated according to the operating condition of the integrated hydraulic system 1 '. It should be noted that a preset constant value may be adopted as the minimum flow rate, and the surplus flow rate calculation unit 74 may not be particularly provided.

As described above, in this embodiment, the total amount of the pressure-adjusted hydraulic oil 02i detected by each flow rate detecting means 6i is obtained, and the total target flow rate signal S is obtained by this total amount.
3'is calculated and the pump discharge hydraulic oil 01, which is the total target flow rate, is obtained by one variable displacement pump 2. Therefore, each directional control valve 31
It is not necessary to provide a target flow rate calculation unit and a variable displacement pump for each i, which is effective in inexpensively manufacturing the integrated hydraulic system 1 '.

FIG. 7 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a third embodiment of the present invention is applied. In this embodiment, the so-called positive control method known in the related art is applied to the method of the above-described second embodiment in which the discharge amount of the variable displacement pump is controlled so as to match the total flow rate of the pressure-adjusted hydraulic oil. In the present embodiment, the total hydraulic system 1 ″
Includes a hydraulic system 10 'having the same configuration as that of the second embodiment, and a control system 50 "in which a target flow rate selection calculation unit (switch control means) 70 is added to the control system 50' of the second embodiment. The target flow rate selection calculation unit 70 includes
When the signal output to the variable displacement pump 2 is switched from one of the target flow rate signal S3 ′ and a required target flow rate signal S3 ″ described later to the other, the value of one signal changes to the other signal. There is built-in switching control means for switching to gradually increase or gradually decrease toward a value.

In this embodiment, as shown in FIG.
From the first operating lever 81 ', the second operating lever 82', ... The nth operating lever 8n 'of the operating lever portion 8 ",
The required target flow rate signal S3i, that is, the first required target flow rate signal S31, the second required target flow rate signal S32, ... The nth target flow rate signal S3n are output according to the manipulated variables.

These required target flow rate signals S3i are signals corresponding to the flow rate output signal S2i, and both relate to the flow rate of the hydraulic oil 0 on the downstream side of the directional control valve 31i, but the flow rate output signal S2i. Is related to the flow rate of the pressure-adjusted hydraulic oil 02i obtained as a result of the pressure control in the pressure control means 3 ', that is, the actuator flow rate signal S1i that actually flows out to the downstream side of the directional control valve 31i, whereas the required target is The flow rate signal S3i is the operation lever 8i '.
The two are different in that they relate to the flow rate determined by the operation amount of.

In the present embodiment, the value indicated by the target flow rate signal S3 'output from the target flow rate calculation section 7'and the value indicated by each required target flow rate signal S3i output from each operation lever 8i' are shown. A comparison calculation with the total value is performed in the target flow rate selection calculation unit 70, and one of the signals indicating the total value of the target flow rate signal S3 ′ and the required target flow rate signal S3i is variable according to a criterion described later. It is adapted to be input to the pump 2.

Therefore, in this embodiment, the value indicated by the target flow rate signal S3 'output from the target flow rate calculation unit 7'and the value indicated by each required target flow rate signal S3i output from each operation lever 8i'. A target flow rate selection calculation unit 70 that performs a comparison calculation with the total value of the above is provided. The target flow rate selection calculation unit 70 is provided with a calculation circuit that sums the values of the required target flow rate signals S3i, and compares the total value calculated by this circuit with the value indicated by the target flow rate signal S3 '. A circuit for performing the calculation is provided, and further, a circuit for determining which value is output as the pump discharge request signal S3 ″ to the variable displacement pump 2 as a result of the comparison calculation is provided.

The contents of the comparison operation will be described in detail below. Here, the total value of the values of the required target flow rate signals S3i set according to the operation amounts of the operation levers 8i ',
That is, the total flow rate value requested by the operating lever is Qd, the value indicated by the target flow rate signal S3 'set as a result of the pressure control in the pressure control means 3', that is, the pressure controlled flow rate value is Qi, and the pump discharge request is made. The signal S3 ″ is set to Qx. Depending on whether or not the difference between Qd and Qi is larger than a threshold value Qlim which is a preset judgment criterion,
One of Qd and Qi is output to the variable displacement pump 2 as a pump discharge request signal S3 ″.

By the way, when the integrated hydraulic system 1 "is operated by operating the operating lever 8i 'in a normal standard state, the value of Qd and the value of Qi are substantially the same,
When the difference between them is calculated over time, it will vary positively and negatively within a minute time centered on 0. Therefore, either one of Qd and Qi is requested to be pumped by the magnitude of Qd and Qi. Setting as the signal S3 ″ increases the frequency of switching between Qd and Qi over time, promotes instability of control that occurs at the time of switching, and is not preferable for stable control. In order to prevent inconvenience, the threshold value Qlim, which is experimentally determined according to the characteristics of each individual hydraulic system 1 ″, is set to prevent hunting.

Specifically, the threshold value Qlim is a transient state at the time of startup, that is, Qd due to the rise of Qi.
From the state where the value of Qd-Qi increases due to the delay of
Tuning is determined for each model and each actuator so that the transition to the steady state, that is, the state where the value of Qd-Qi is sufficiently small can be performed as smoothly as possible.

In the present embodiment, Qi is adopted as Qx when Qd-Qi> Qlim ............, and as Qx when Qd-Qi≤Qlim. Qd has been adopted.

These things specifically represent the following contents. That is, normally, in a standard quiet driving operation, since the operation of the operation lever 8i is carefully and slowly performed, the operation lever required total flow rate value (Qd) becomes substantially the same as the pressure controlled flow rate value (Qi). And Qd-Qi
The value of fluctuates positively and negatively around 0 with time.
Therefore, for example, if the threshold value Qlim is set to the value of 3σ of the variation in the positive direction, the condition of the above expression is normally satisfied, and the pump discharge request signal in which the operation of the operation lever 8i ′ is prioritized. Since S3 ″ is output from the target flow rate selecting / calculating unit 70 toward the variable displacement pump 2, the pressure control in the pressure control means 3 ′ is canceled and so-called positive control is executed.

On the other hand, the operating lever 8 which is extremely abrupt
When the operation of i'is performed, the operation lever required total flow rate value (Qd) becomes much larger than the pressure controlled flow rate value (Qi), exceeding the range of variation. Such a state is a state in which a flow rate extremely higher than the flow rate of the pressure-adjusted hydraulic oil 02i actually supplied to each actuator 4i by the abrupt operation of the operation lever 8i 'is requested. If a variable flow rate is actually discharged from the variable displacement pump 2, normal control may not be performed and may cause equipment damage.

Therefore, when the condition of the above equation is met, that is, when the value of Qd-Qi becomes larger than the value of the threshold value Qlim, Qi is adopted as Qx, and the target flow rate signal S3 'remains unchanged. The same pressure control as in the second embodiment, which is output to the variable displacement pump 2 as the pump discharge request signal S3 ″, is executed.

In this embodiment, in order to soften the so-called switching shock that occurs when the pump discharge request signal S3 ″ is switched between Qd and Qi, the signal value is continuously switched. In order to perform such processing, a continuous switching circuit may be formed in the target flow rate selection calculation unit 70.

Hereinafter, the pump discharge request signal S3 ″ is set to Qd and Q.
A method of continuously switching between i and i will be described.
For this continuous switching, in this embodiment, the time-varying weighted average value is used for gradual switching and hysteresis is taken into consideration when switching. That is, at the time of switching, the value of Qx is calculated using the time-varying weighting coefficient W (t) that is a function of the elapsed time, and once Q
When Qi is adopted as x and converted to adopt Qd, a hysteresis value (Qhys) that does not cause a problem even if changed to Qd is included in the criterion.

In the above W (t), when the Qx is converted from Qd to Qi, that is, at the present time, the discharge amount control of the variable displacement pump 2 by the operation of the operation lever 8i 'is prioritized, which is the pressure control. When converted to, it is calculated by the following formula. W (t) = α × t (where 0 ≦ W (t) ≦ 1) ... where α is a proportional constant and t is an elapsed time from the start of conversion. The conversion ends when the value of W (t) reaches 1. The change with time of W (t) is shown in FIG. The timing of this calculation is when Qd-Qi> Qlim ....

On the contrary, when Qx is converted from Qi to Qd, that is, at present, the discharge amount control of the variable displacement pump 2 by pressure control is prioritized, which is the operation lever 8
When converted into the one by the operation of i ′, W (t) is calculated by the following formula. W (t) = 1−α × t (where 0 ≦ W (t) ≦ 1) ... In the case of the equation, α is a proportional constant and t is an elapsed time from the start of conversion. The conversion ends when the value of W (t) reaches 0. The change with time of W (t) is shown in FIG. The time when this calculation is performed is the time when Qd−Qi ≦ Qlim−Qhys.

Then, such a time-varying weight coefficient W (t)
Qx is calculated by the following equation using Qx = Qi * W (t) + Qd * (1-W (t)) ... This Qx value is directed to the variable displacement pump 2 as the pump discharge request signal S3 ″. Is output.

In the present embodiment, the time-varying weight coefficient (W (t)) and the hysteresis value (Qhys) are taken into consideration as described above, and Qx gradually changes from Qi to Qd or from Qd to Qi over time. Since it is converted, the conversion shock during conversion is effectively suppressed, and the variable displacement pump 2 due to the shock is converted.
The fluctuation of the discharge amount is suppressed, which is convenient for properly performing pressure control.

In the third embodiment, Qi is the first target flow rate signal S31 and the second target flow rate signal S32.
The sum of the values of the nth target flow rate signal S3n is applied, and the discharge amount of the variable displacement pump 2 is comprehensively controlled by the pressure control means 3 ', but in the present invention, Qi is the above sum. The value is not limited to the value, and the above control may be performed for each directional control valve 31i.

Further, even if the operation levers 8i 'do not have the function of outputting the required target flow rate signal, that is, the operation levers 8i' are not added with the flow rate control function, the operation lever 8i 'of the third embodiment is used. Control is possible. In this case, Qi is always selected for those without a flow rate control function, and for those with a flow rate control function, the control method is appropriately switched according to the situation.

[0092]

As described above in detail, the discharge amount control device for a hydraulic pump according to claim 1 of the present invention comprises a control means for controlling the discharge pressure of the hydraulic pump for supplying hydraulic oil to the actuator. A discharge amount control device for a hydraulic pump, comprising: a flow amount detecting means for detecting an actuator flow amount actually flowing through an actuator; and a discharge amount for controlling the discharge amount of the hydraulic pump to be substantially equal to the actuator flow amount detected by the flow amount detecting means. And a quantity control means.

Therefore, from the hydraulic pump, discharge is performed by pressure control in proportion to the flow rate of the working oil actually supplied to the actuator, and as a result, the work substantially corresponding to the working oil actually required by the actuator is performed. Since the oil is discharged from the hydraulic pump, it is possible to reduce the amount of surplus hydraulic oil that always occurs in the oil balance for pressure control to the necessary minimum amount, and discharge the working oil accordingly. The amount of energy can be saved, which is extremely useful in reducing operating costs.

According to the discharge amount control device of the hydraulic pump of the second aspect, since the value of the actuator flow rate detected by the flow rate detecting means is smoothed by the target flow rate calculating section, it is detected by the normal flow rate detecting means. The obtained raw value slightly fluctuates over time, but such a variation is eliminated, and stable feedback control can be performed. In addition, since the signal of the target flow rate, in which a small amount is added to the smoothed value above, is input to the hydraulic pump, the minimum excess hydraulic oil necessary for oil balance is secured by this addition, and the hydraulic pressure is maintained. This is convenient for stably driving the pump.

Further, according to a third aspect of the present invention, there is provided a hydraulic pump discharge amount control device for controlling a discharge pressure of each actuator of a hydraulic pump which is shared for supplying hydraulic oil to a plurality of actuators. A discharge amount control device for a hydraulic pump comprising: a plurality of flow rate detecting means for detecting a flow rate of each actuator actually flowing through each actuator; and a flow rate detecting value of the hydraulic pump based on a flow rate detection value detected by the flow rate detecting means. And a discharge amount control means for controlling the discharge amount.

Therefore, the discharge amount control means performs a predetermined control based on the flow rate detection value of each flow rate detection means to control the discharge amount of the hydraulic pump to an appropriate value. Then, among the plurality of actuators, there are mixed actuators that perform pressure control, actuators whose valve opening is determined by the amount of lever operation, and actuators whose valve opening is determined by a flow rate command signal from a host controller. In this case, the discharge amount control means provides the discharge amount of the hydraulic pump for the latter two parties as well as the total of the hydraulic pumps by detecting the flow rate by providing the flow rate detection means like the actuator for pressure control. In order to control the discharge amount, with respect to the actuators for which the pressure is controlled, the hydraulic oil is discharged substantially in proportion to the total flow rate of the working oil supplied to those actuators.

As described above, the hydraulic pump discharges by the pressure control in accordance with almost the total flow rate of the working oil actually supplied to each actuator, and as a result, each actuator is actually required. Working oil is supplied, the amount of surplus hydraulic oil that is always generated in terms of the oil amount balance for pressure control can be reduced to the necessary minimum amount, and the amount of energy for discharging working oil correspondingly can be reduced. The amount can be saved, which is extremely useful in reducing the operating cost.

According to the discharge amount control device of the hydraulic pump of the fourth aspect of the present invention, since the values of the respective actuator flow rates detected by the flow rate detecting means are smoothed by the target flow rate calculating section, the normal flow rate is obtained. Although the raw value detected by the detecting means varies slightly with time, such a variation is eliminated and stable feedback control can be performed. In addition, since the signal of the target flow rate, in which a small amount is added to the smoothed value above, is input to the hydraulic pump, the minimum excess hydraulic oil necessary for oil balance is secured by this addition, and the hydraulic pressure is maintained. This is convenient for stably driving the pump.

According to the discharge amount control device of the hydraulic pump of the fifth aspect, the operating means for outputting the required target flow rate signal for obtaining the desired actuator flow rate according to the operation amount is provided, and the target flow rate calculation is performed. The unit is configured to output a target flow rate signal corresponding to the actuator flow rate detected by the flow rate detecting means, and determines whether the value of the target flow rate signal is sufficiently close to the value of the required target flow rate signal. Since the target flow rate selection calculation unit for selecting one of the required target flow rate signal and the target flow rate signal by discrimination and inputting it to the hydraulic pump is provided, the value (Qd) of the required target flow rate signal is used. When a value obtained by subtracting the value (Qi) of the target flow rate signal is equal to or smaller than a predetermined threshold value (Qlim) which is a sufficiently close value set in advance (Q
d-Qi ≦ Qlim), that is, when the operation unit is performing a normal operation, the target flow rate selection calculation unit selects the required target flow rate signal (Qd) output from the operation unit, and thereby the hydraulic pressure is set. Since the working oil is discharged from the pump to operate the actuator, the operation in which the intention of the driver who operates the operating means is reflected is realized.

On the other hand, when Qd-Qi> Qlim, that is, when the operating means is suddenly operated, the target flow rate selecting / calculating unit automatically obtains the target flow rate signal obtained by the pressure control of the system. Since (Qi) is selected, the working oil is discharged from the hydraulic pump, so that temporary excessive discharge from the hydraulic pump is suppressed.

On the other hand, when Qd-Qi> Qlim, that is, when the operating means is rapidly operated, the target flow rate selecting / calculating section automatically sets the target flow rate signal (Qi) obtained by pressure control of the system. ) Is selected, the working oil is discharged from the hydraulic pump, and temporary excessive discharge from the hydraulic pump is suppressed, which is convenient for maintenance of the apparatus.

According to the discharge amount control device for a hydraulic pump described in claim 6, the signal output to the hydraulic pump is switched from one of the required target flow rate signal and the target flow rate signal to the other. In this case, since the switching control means switches the value of one signal so as to gradually increase or gradually decrease toward the value of the other signal, it is possible to avoid a sudden change in the discharge amount of the hydraulic pump. Therefore, it is extremely effective in properly operating the hydraulic pump.

[Brief description of drawings]

FIG. 1 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a first embodiment of the present invention is applied.

FIG. 2 is a block diagram for explaining a pressure control means and a flow rate detection means of the first embodiment.

FIG. 3 is a block diagram showing a flow rate calculation unit and a target flow rate calculation unit of flow rate detection means.

FIG. 4 is a block diagram showing a control system of a variable displacement pump.

FIG. 5 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a second embodiment of the present invention is applied.

FIG. 6 is a block diagram showing an internal configuration of a target flow rate calculation unit of the second embodiment.

FIG. 7 is a general block diagram showing a hydraulic system and a control system to which a discharge amount control device for a hydraulic pump according to a third embodiment of the present invention is applied.

FIG. 8 is a graph showing a change of the time-varying weight coefficient with time, where (a) shows a state in which the time-varying weight coefficient gradually increases from 0 to 1,
(B) shows a state in which the time-varying weight coefficient gradually decreases from 1 to 0.

[Explanation of symbols]

 1 Integrated hydraulic system 10, 10 'Hydraulic system 2 Variable displacement pump 21 Swash plate type piston pump 21a Pump body 21b Tilt angle displacement mechanism 22 Control section 23 Tilt angle calculation section 24 Amplifier 3, 3'Pressure control means 31 Direction control valve 311 1st directional control valve 31n nth directional control valve 31a Spool 31b Valve movable part 31c Valve opening detection means 32 Control calculation part 33 Amplifier 34 Electromagnetic proportional pressure reducing valve 35 Control valve part 4 Actuator 41 1st actuator 4n nth actuator 40 Working member 401 First working member 40n nth working member 50, 50 ′, 50 ″ Control system 6 Flow rate detecting means 60 Flow rate calculating section 61 First flow rate detecting means 6n nth flow rate detecting means 7, 7 ′ Target flow rate calculating section 70 Switching control means 71 Smoothing processing section 72 Overlay processing section 8 Operation lever 81 First operation Work lever 8n nth operation lever S1 actuator flow rate signal S11 first actuator flow rate signal S1n nth actuator flow rate signal S2 flow rate signal S21 first flow rate signal S2n nth flow rate signal S3 target flow rate signal S3 ′ target flow rate signal S4 pressure command signal S41 1st pressure command signal S4n nth pressure command signal S5 deviation signal S6 valve displacement command signal S7 valve opening signal S8 upstream side pressure detection signal S9 downstream side pressure detection signal S10 engine speed signal 0 hydraulic oil 01 pump discharge hydraulic oil 02 Pressure adjusted hydraulic oil 021 1st pressure adjusted hydraulic oil 02n nth pressure adjusted hydraulic oil 03 Surplus hydraulic oil 04 Return hydraulic oil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Kobayashi 740 Yagi, Okubo-cho, Akashi City, Hyogo Prefecture Kobe Steel Works Okubo Construction Machinery Factory (72) Inventor Seigo Arai 740 Yagi, Okubo-cho, Akashi City, Hyogo Prefecture Company Kobe Steel Okubo Construction Machinery Factory (72) Inventor Makoto Makuzen 1-5-5 Takatsukadai, Nishi-ku, Kobe City Stock Company Kobe Steel Works Kobe Research Institute

Claims (6)

[Claims] 1. A discharge amount control device for a hydraulic pump, comprising a control means for controlling a discharge pressure of a hydraulic pump for supplying hydraulic oil to the actuator, wherein the flow rate detection device detects an actuator flow amount actually flowing to the actuator. A discharge amount control apparatus for a hydraulic pump, comprising: a discharge amount control unit for controlling the discharge amount of the hydraulic pump to be substantially equal to the actuator flow rate detected by the flow rate detection unit. 2. A target flow rate calculating section for smoothing the value of the actuator flow rate detected by the flow rate detecting means, and superimposing a small amount on it to calculate a target flow rate, the hydraulic pump 2. The discharge amount of is controlled to be the target flow rate.
Discharge amount control device for the hydraulic pump described. 3. A discharge amount control device for a hydraulic pump, comprising: a control means for controlling the discharge pressure of each actuator of a hydraulic pump shared for supplying hydraulic oil to a plurality of actuators. A plurality of flow rate detecting means for detecting the flow rate of each actuator actually flowing, and a discharge rate control means for controlling the discharge rate of the hydraulic pump based on the flow rate detection value detected by the flow rate detecting means are provided. Discharging amount control device of the characteristic hydraulic pump. 4. The value of each actuator flow rate detected by the plurality of flow rate detecting means is smoothed, and
It is characterized in that a target flow rate calculation unit for calculating a target flow rate by adding a small amount to these is provided, and the discharge rate of the hydraulic pump is controlled to be the total value of the target flow rates. The discharge amount control device for a hydraulic pump according to claim 3. 5. An operating means for outputting a required target flow rate signal for obtaining a desired actuator flow rate according to a manipulated variable is provided, and the target flow rate calculating section outputs a target corresponding to the actuator flow rate detected by the flow rate detecting means. It is configured to output a flow rate signal, and by determining whether or not the value of the target flow rate signal is sufficiently close to the value of the required target flow rate signal, the required target flow rate signal and the target flow rate signal The discharge amount control device for a hydraulic pump according to claim 2 or 4, further comprising a target flow rate selection calculation unit that selects either one and inputs it to the hydraulic pump. 6. When the signal output to the hydraulic pump is switched from one of the required target flow rate signal and the target flow rate signal to the other, the value of one signal is changed to the value of the other signal. 6. The discharge amount control device for a hydraulic pump according to claim 5, further comprising switching control means for switching to gradually increase or decrease with time.