JP2871909B2 - Actuator control device for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator control device for a construction machine which is provided in a construction machine such as a hydraulic shovel and controls a drive of a direction control valve by operating a pilot valve to operate an actuator.

[0002]

2. Description of the Related Art FIG. 9 is a circuit diagram showing a basic configuration of a conventional actuator control device for a construction machine of this kind.

In the prior art shown in FIG. 9, a main hydraulic source 5, an actuator 3 driven by pressure oil supplied from the main hydraulic source 5, and an actuator 3 supplied from the main hydraulic source 5 to the actuator 3. A directional control valve 2 for controlling the flow of pressurized oil, a pilot valve 1 for controlling the driving of the directional control valve 2, and a pilot hydraulic pressure source 4 for supplying pilot pressure to the pilot valve 1;
A restricting means 7 for restricting the transmission speed of the pilot pressure transmitted from the pilot valve 1 to the driving unit of the direction control valve 2 is provided in a passage communicating with the driving unit of the direction control valve 2. The restricting means 7 communicates between the throttle valves 7a and 7b provided in the passage connecting the pilot valve 1 and the drive unit of the direction control valve 2, and the upstream and downstream sides of these throttle valves 7a and 7b. A check valve 7c provided in the bypass passage for preventing a reverse flow of pilot pressure from the drive unit of the direction control valve 2 toward the pilot valve 1; a reverse flow of pilot pressure from the pilot valve 1 toward the drive unit of the direction control valve 2; Check valve 7d
And

In general, in this type of construction machine, the operation amount of the pilot valve 1, that is, the speed of the actuator 3 with respect to the lever stroke, that is, the actuator speed does not change linearly and has some characteristics as shown in FIG. It is often set in advance so that
Such characteristics are appropriately set as appropriate depending on the type of the actuator.

By the way, in a device having such characteristics, when no means is provided, for example, when the actuator 3 is started, when the pilot valve 1 is suddenly operated, as shown in a region A of FIG. Inevitably, the actuator speed will increase, causing a shock,
The operation feeling given to the operator is deteriorated.

In the prior art shown in FIG. 9, from such a viewpoint, the above-mentioned regulating means 7 is provided, and when the pilot valve 1 is suddenly operated when the actuator 3 is started,
The pilot pressure applied from the pilot valve 1 to the drive unit of the directional control valve 2 is reduced by the throttle valve 7b, the transmission speed of the pilot pressure at the time of activation is reduced, the rising speed of the actuator 3 is reduced, and Shock is alleviated, and when the pilot valve 1 is suddenly operated when the actuator 3 is stopped, the decreasing speed of the decreasing pilot pressure is regulated by the throttle valve 7a so that the shock at the time of stop is alleviated. It is. The pilot pressure P applied to the drive unit of the direction control valve 2 with respect to the time t at this time.
The relationship _{2 is} a relationship that gradually increases as shown by the broken line portion in FIG.

[0007]

In the prior art shown in FIG. 9, the throttle valve 7a, 7b of the regulating means 7 can reduce the shock at the time of starting or stopping the actuator 3, but the throttle valve 7a , 7b, the time from the start of the operation of the pilot valve 1 to the point B at which the actuator 3 starts driving or starts the stop operation as shown by T ₁ and T ₂ in FIG. Take
From this viewpoint, there is a problem that responsiveness is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances in the prior art, and has as its object to reduce the shock associated with the actuation and stop operations of an actuator and to provide an actuator of a construction machine capable of obtaining excellent responsiveness. It is to provide a control device.

[0009]

In order to achieve this object, the present invention provides a main hydraulic pressure source, an actuator driven by pressure oil supplied from the main hydraulic pressure source, and an actuator supplied from the main hydraulic pressure source to the actuator. A directional control valve for controlling the flow of pressurized oil, a pilot valve for controlling the drive of the directional control valve, and a pilot hydraulic source for supplying pilot pressure to the pilot valve. A throttle means is provided in a passage connecting the drive unit of the direction control valve and the pilot valve,
A bypass passage communicating between the upstream side and the downstream side of the throttle unit is provided, and an opening / closing unit for opening and closing the bypass passage according to the downstream pressure of the throttle unit is provided in the bypass passage.

[0010]

Since the present invention has the above-mentioned structure, by appropriately setting the set pressure of the opening / closing means, it is possible to set the opening / closing means in a region where shock mitigation is required as exemplified in a region A of FIG. Can be closed and the pilot pressure applied to the drive unit of the directional control valve by the throttle means can be gently increased or decreased. Except in a region where shock mitigation is not required, the directional control valve is not affected by the throttle valve. The pilot pressure applied to the drive can be rapidly increased or decreased, thereby obtaining excellent actuator responsiveness to pilot valve operation.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a construction machine actuator control apparatus according to an embodiment of the present invention.

FIG. 1 is a circuit diagram showing one embodiment of the present invention. In FIG. 1, the same components as those of the prior art shown in FIG. 9 are denoted by the same reference numerals. That is, also in FIG. 1, the main oil pressure source 5, the actuator 3 driven by the pressure oil supplied from the main oil pressure source 5, and the flow of the pressure oil supplied from the main oil pressure source 5 to the actuator 3 are controlled. The directional control valve 2 includes a pilot valve 1 that controls driving of the directional control valve 2, and a pilot hydraulic pressure source 4 that supplies a pilot pressure to the pilot valve 1.

In this embodiment, a pilot pressure control means 8 for controlling the magnitude of the pilot pressure applied to the drive unit of the directional control valve 2 is provided between the drive unit of the directional control valve 2 and the pilot valve 1. 9 are provided. Among these, the pilot pressure control means 8 is a throttle means provided in the passage 6 which connects the pilot valve 1 and the drive unit of the direction control valve 2, that is, a throttle valve 8a, and an upstream side and a downstream side of the throttle valve 8a. The communicating bypass passages 8b and 8c and the bypass passage 8b
Opening / closing means for opening / closing the bypass passage 8b according to the downstream pressure of the throttle valve 8a, that is, an opening / closing valve 8d;
A check valve 8e is provided in the bypass passage 8c and prevents a backflow of pressure oil from the drive unit of the direction control valve 2 toward the pilot valve 1. Further, the pilot pressure control means 9
Is a throttle means provided in a passage 6 which connects the pilot valve 1 and a drive unit of the direction control valve 2, that is, a throttle valve 9a
Opening / closing means provided in the bypass passage 9b for connecting the upstream side and the downstream side of the throttle valve 9a and opening / closing the bypass passage 9b in accordance with the downstream pressure of the throttle valve 9a; Valve 9d and bypass passage 9
c and a check valve 9e for preventing backflow of pressure oil from the pilot valve 1 toward the drive section of the direction control valve 2.

The operation of the embodiment configured as described above is as follows. That is, before the lever of the pilot valve 1 is operated, the pilot pressure, that is, the throttle valve 8a
Is smaller than the set pressure of the spring of the on-off valve 8d,
The on-off valve 8d is switched to the lower position in FIG. 1 and is kept at the closed position, and the downstream pressure of the throttle valve 9a is reduced by the on-off valve 9d.
The opening / closing valve 9d is switched to the lower position in FIG. 1 and is kept at the open position.

When the lever of the pilot valve 1 is operated with the intention of activating the actuator 3 in this state, the pilot stroke is increased as indicated by a characteristic line 21 as the lever stroke S increases as indicated by a characteristic line 20 in FIG. pilot pressure P ₁ which is output from the valve 1 is increased. At this time, the pilot pressure oil flows through the passage 6 via the bypass passage 8c and the check valve 8e of the pilot control means 8, and further to the drive unit of the direction control valve 2 via the on-off valve 9d of the pilot control means 9. given instant as the pilot pressure P ₂ as shown by a characteristic line 22 in FIG. 2. Thereafter, the pilot pressure P ₂ off valve 9d, becomes larger than the set pressure of 8d of the spring, off valve 9d, 8d is switched to the upper position of FIG. 2, the bypass passage 9b is interrupted, the bypass passage 8b is communicated . Therefore, the pilot pressure oil that has passed through the pilot control unit 8 is supplied to the drive unit of the directional control valve 2 via a throttle valve 9a, by the speed of increase in the pilot pressure P ₂ is throttled by the throttle valve 9a, It is controlled so that it becomes gentle. When the lever of the pilot valve 1 is operated to its full stroke, the pilot pressure P ₂ applied to the drive unit of the directional control valve 2 becomes constant, the actuator 3 shown in FIG. 1 are driven at a constant speed.

From the state where the actuator 3 is being driven, the actuator 3 is intended to be stopped.
Returning pilot valve 1, as shown in the characteristic line 20, the pilot pressure P ₁ which is output from the pilot valve 1, as shown by the characteristic line 21 is reduced. At this time, the pilot pressure P ₂
Is greater than the set pressure of the springs of the on-off valves 8d and 9d,
The pressure oil in the passage 6 is returned to the tank at a high speed via the check valve 9e and the on-off valve 8d of the pilot control means 8, and the decreasing speed of the pilot pressure is large as shown by the characteristic line in FIG. The pilot pressure P ₂ off valve 8d, becomes smaller than the set pressure of 9d of the spring, off valve 8d, 9d are returned to each lower position, the bypass passage 8b is interrupted, the bypass passage 9B communicates. Therefore, it returned to the tank via a pilot pressure oil throttle valve 8a of the passage 6, by the rate of decrease of the pilot pressure P ₂ is throttled by the throttle valve 8a, is controlled to be gentle.

FIG. 3 shows a characteristic line 20 and a characteristic line 2 shown in FIG.
In FIG. 3, B indicates the drive start time and the stop operation start time of the actuator 3 shown in FIG. As shown by the characteristic line 22 in FIG.
In the present embodiment, the drive start of the actuator 3 increases the pilot valve 1 operation immediately after the start of the pilot pressure P ₂ of the lever, and when the drive stop of the actuator 3 of the immediately following operating the start of lever pilot valve 1 Pilot pressure P ₂
The time t ₁ from the start of the operation of the lever of the pilot valve 1 when the actuator 3 is driven to the start B of the operation of the actuator 3, and the operation of the lever of the pilot valve 1 when the actuator 3 is stopped. the time t ₂ from the start point to the stop operation starting point B actuator 3 can be sufficiently shortened. In FIG. 3, the characteristic line indicated by the broken line at the characteristic line 22 is the characteristic line in the prior art shown in FIG.
Since the influence of the throttle valve from the start of the operation of the lever of the pilot valve 1, the degree of increase and decrease of the pilot pressure is moderate, and accordingly, the start of the operation of the lever of the pilot valve 1 when the actuator 3 is driven. , The time T ₁ from the start of the operation of the actuator 3 to the start of driving of the actuator 3 is longer than the time t ₁ of the present embodiment. time T ₂ of the up stop operation start time is longer than the time t ₂ of the present embodiment. In the present embodiment, the actuator 3 can be driven after the time t ₁ from the start of the operation of the lever of the pilot valve 1, and the actuator 3 can be stopped after the time t ₂ , Valves 9a, 8
The pilot pressure applied to the drive unit of the directional control valve 2 is gradually increased or gradually decreased by the throttle action of “a”, so that the shock can be reduced.

As described above, in this embodiment, the actuator 3 can be driven or stopped in a relatively short time after the operation of the pilot valve 1 for driving or stopping the actuator 3 is started. As a result, the shock generated when the actuator is started or stopped due to the sudden operation of the pilot valve 1 can be reduced.

FIG. 4 is a circuit diagram showing another embodiment of the present invention.

In the embodiment shown in FIG. 4, the pilot pressure control means 10 provided in the passage 6 for connecting the pilot valve 1 and the drive unit of the direction control valve 2 includes a throttle valve 10a provided in the passage 6, The bypass passage 10b connects the upstream side and the downstream side of the throttle valve 10a, and an opening / closing valve 10c provided in the bypass passage 10b to open and close the bypass passage 10b according to the downstream pressure of the throttle valve 10a. .

In this embodiment, when the actuator 3 is started, when the pilot valve 1 is operated, while the downstream pressure of the throttle valve 10a is smaller than the set pressure of the spring of the on-off valve 10c, the on-off valve is opened. In FIG. 1, reference numeral 10c denotes a state in which the pilot pressure P2 applied to the drive unit of the directional control valve ₂ is increased at a high speed until the actuator 3 is activated, while the lower position of the FIG. As in the example, a short response was obtained, and excellent responsiveness was obtained.
When the downstream pressure of a becomes larger than the set pressure of the spring of the on-off valve 10c, the on-off valve 10c is switched to the upper position in FIG. 4, that is, the closed position, so that the pilot pressure oil flows in the direction through the throttle valve 10a. The throttle pressure is supplied to the drive section of the control valve 2 and the pilot pressure P
₂ is controlled so that the increasing speed becomes slow, and the shock can be reduced.

When the actuator 3 is stopped, when the pilot valve 1 is operated, while the downstream pressure of the throttle valve 10a is larger than the set pressure of the spring of the on-off valve 10c,
Off valve 10c is kept in the upper or closed position of FIG. 4, the pilot pressure oil through the throttle valve 10a is returned to the tank, the rate of decrease in the pilot pressure P ₂ by throttling action of the throttle valve 10a is gradually When the downstream pressure of the throttle valve 10a becomes smaller than the set pressure of the spring of the on-off valve 10c, the on-off valve 1 is controlled.
0c is switched to the lower position of FIG. 4, that is, the open position, and the pilot pressure oil in the passage 6 is instantly returned to the tank,
The directional control valve 2 quickly returns to neutral. Even in the embodiment configured as described above, similarly to the embodiment illustrated in FIG. 1 described above, it is possible to reduce the shock when driving the actuator 3 and obtain excellent responsiveness.

FIGS. 5 to 8 are diagrams showing another example of the pilot control means provided in the passage 6 which connects the pilot valve 1 and the drive unit of the direction control valve 2, respectively.

The pilot control means 11 shown in FIG. 5 includes a throttle valve 11a provided in the passage 6, a bypass passage 11b connecting the upstream side and the downstream side of the throttle valve 11a, and an on-off valve provided in the bypass passage 11b. 11c, the on-off valve 11c is kept in the closed position when the downstream pressure of the throttle valve 11a is smaller than the set pressure of the spring, and is opened when the downstream pressure is larger than the set pressure of the spring. Can be switched over. This pilot control means 11
Is particularly effective in alleviating a shock that may occur in a region where the stroke of the pilot valve 1 is small. When the downstream pressure of the throttle valve 11a becomes larger than the set pressure of the spring, the pilot portion of the directional control valve 2 is promptly actuated. Pressure, or quickly return the pilot pressure oil in passage 6 to the tank,
Excellent responsiveness is obtained. .

The pilot control means 9 shown in FIG. 6 is the same as that shown in FIG. In the circuit shown in FIG. 1, only the pilot control means 9 may be provided. This configuration is particularly effective when only a shock at the time of driving the actuator 3 is concerned. During driving, while the downstream pressure of the throttle valve 9a is smaller than the set pressure of the spring of the on-off valve 9d. Bypass passage 9
The pilot pressure is supplied to the drive unit of the directional control valve 2 via the valve b to promptly start the drive of the actuator 3, thereby ensuring excellent responsiveness. The downstream pressure of the throttle valve 9a is reduced by the spring of the on-off valve 9d. When the set pressure becomes larger than the set pressure, the on-off valve 9d is switched to shut off the bypass passage 9b, and the shock is reduced by the throttle action of the throttle valve 9a. When the actuator 3 is stopped, the pilot pressure oil is immediately returned to the tank via the check valve 9e, and the direction control valve 2 is quickly returned to the neutral position.

The pilot control means 9 shown in FIG.
In place of the check valve 9e shown in FIG. 7, a check valve 9f for preventing a reverse flow from the drive unit of the direction control valve 2 toward the pilot valve 1 is provided. In the circuit shown in FIG. 1, only the pilot control means 9 shown in FIG. 7 may be provided. This configuration is particularly effective when only a shock when the actuator 3 is stopped is concerned. When the actuator 3 is driven, the pilot pressure oil is instantaneously supplied to the direction control valve via the check valve 9f. 2 to drive the actuator 3 immediately. The pilot control means 12 shown in FIG.
A throttle valve 12a provided in the passage 6, and bypass passages 12b, 12c, 12 connecting the upstream side and the downstream side of the passage 6
d, an opening / closing valve 12f provided in the bypass passage 12b and switched to the closed position when the downstream pressure of the throttle valve 12a becomes larger than the set pressure of the spring, and an opening / closing valve 12f provided in the bypass passage 12c. The on-off valve 12e is set to be larger than the set pressure of the spring of the valve 12f and is switched to the open position when the downstream pressure of the throttle valve 12a becomes larger than the set pressure of the spring. And a check valve 12g for preventing backflow of the direction control valve 2 in the direction of the drive section.
In the circuit shown in FIG. 1, only the pilot control means 12 shown in FIG. 8 may be provided. Such a configuration is particularly effective when only a shock at the time of driving the actuator 3 is concerned, and it is assumed that a region where a shock is likely to occur is a specific region after the start of activation of the actuator 3. This is effective when That is, during driving, while the downstream pressure of the throttle valve 12a is smaller than the set pressure of the spring of the on-off valve 12f, the pilot pressure is supplied to the drive unit of the direction control valve 2 via the bypass passage 12b, and the actuator 3 is quickly driven. When the downstream pressure of the throttle valve 9a is larger than the set pressure of the spring of the on-off valve 12f and smaller than the set pressure of the spring of the on-off valve 12e, the on-off valve 12f is switched and the bypass passage 12b is shut off. Since the on-off valve 12e is kept in the closed position, the bypass passage 12c is also cut off, so that the shock is reduced by the throttle action of the throttle valve 12a, and the downstream pressure of the throttle valve 9a is reduced.
When the spring pressure becomes greater than the set pressure of the spring e, the on-off valve 12e is also switched to the open position, and the pilot pressure is promptly supplied to the drive unit of the direction control valve 2 via the bypass passage 12c. Thereby, excellent responsiveness and shock mitigation can be ensured. In addition,
When the actuator 3 is stopped, the pilot pressure oil in the passage 6 is instantaneously returned to the tank via the check valve 12g, and the direction control valve 2 quickly returns to neutral.

In the present invention, the various pilot control means shown in FIGS. 1 and 4 to 8 or the pilot control means similar to these pilot control means are selected in accordance with the operation mode of the actuator 3. It is also possible to adopt a configuration in which various regions are set in various ways, including a region for alleviating shock and a region for ensuring responsiveness.

[0028]

As described above, according to the present invention, the shock at the time of starting or stopping the actuator can be reduced, and excellent responsiveness can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of an actuator control device for a construction machine according to the present invention.

FIG. 2 shows the stroke characteristics of the pilot valve obtained in the embodiment shown in FIG. 1, the pilot pressure characteristic on the pilot valve side of the pilot pressure guided to the passage connecting the parrot valve and the directional control valve, and the directional control valve side. FIG. 3 is a characteristic diagram showing respective pilot pressure characteristics.

FIG. 3 shows stroke characteristics of the pilot valve shown in FIG. 2;
It is the figure which showed and compared the pilot pressure characteristic of the direction control valve side.

FIG. 4 is a circuit diagram showing another embodiment of the actuator control device for a construction machine according to the present invention.

FIG. 5 is a diagram showing another example of the pilot control means constituting the actuator control device for a construction machine according to the present invention.

FIG. 6 is a diagram showing another example of the pilot control means constituting the actuator control device of the construction machine of the present invention.

FIG. 7 is a diagram showing another example of the pilot control means constituting the actuator control device for a construction machine according to the present invention.

FIG. 8 is a diagram showing another example of the pilot control means constituting the actuator control device for a construction machine according to the present invention.

FIG. 9 is a circuit diagram showing a conventional actuator control device for a construction machine.

FIG. 10 is a characteristic diagram showing an example of a relationship between a lever stroke and an actuator speed, which is generally considered when driving an actuator of a conventional construction machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pilot valve 2 Directional control valve 3 Actuator 4 Pilot oil pressure source 5 Main oil pressure source 6 Passage 8 Pilot pressure control means 8a Throttle valve (throttle means) 8b Bypass passage 8c Bypass passage 8d Open / close valve (open / close means) 8e Check valve 9 Pilot Pressure control means 9a Throttle valve (throttle means) 9b Bypass passage 9c Bypass passage 9d Open / close valve (open / close means) 9e Check valve 9f Check valve 10 Pilot pressure control means 10a Throttle valve (throttle means) 10b Bypass passage 10c Open / close valve ( Opening / closing means) 11 pilot pressure control means 11a throttle valve (throttling means) 11b bypass passage 11c opening / closing valve (opening / closing means) 12 pilot pressure control means 12a throttle valve (throttling means) 12b bypass passage 12c bypass passage 12d bypass passage 12e opening / closing valve Opening / closing means) 12f On-off valve ( Opening / closing means) 12g check valve

Continuation of the front page (56) References JP-A-2-279841 (JP, A) JP-A-5-8003 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02F 9 / twenty two

Claims (1)

(57) [Claims] 1. A main oil pressure source, an actuator driven by pressure oil supplied from the main oil pressure source, a direction control valve for controlling a flow of pressure oil supplied from the main oil pressure source to the actuator, and a direction control valve for the direction control valve In an actuator control device for a construction machine having a pilot valve for controlling the driving of a valve and a pilot hydraulic pressure source for supplying a pilot pressure to the pilot valve, a passage communicating between the drive unit of the direction control valve and the pilot valve And a throttle means
An actuator control system for a construction machine, comprising: a bypass passage connecting the upstream side and the downstream side of the throttle unit; and an opening / closing unit for opening and closing the bypass passage in accordance with a downstream pressure of the throttle unit. apparatus.