JPH07248002A - Turn control device for working machine - Google Patents

Abstract

PURPOSE:To provide a control function optimum for the content of a work, the taste of an operator or the like. CONSTITUTION:A control mode setting unit 23 optionally selects a suitable one of several kinds of output patterns which give different variation rates of pump discharge rate with respect to variations in engine speed, for a controller 20 which delivers an instruction signal indicating a pump discharge rate to a proportional pressure-reducing solenoid valve 17 for a flow regulator 19 in accordance with a speed of the engine 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning control device for controlling a turning operation of a working machine having a turning function such as a crane.

[0002]

2. Description of the Related Art Conventionally, as a turning control device, a hydraulic pump 2 driven by an engine 1 as shown in FIG.
And the swing motor 3 are connected via a swing control valve 4, and the swing speed is adjusted by adjusting the stroke of the control valve 4 (hereinafter referred to as a valve control system) and adjusting the engine speed (hereinafter referred to as a rotation speed control system). It is generally configured to control the. 5 is a relief valve.

[0003]

However, according to the conventional configuration in which only two control methods (patterns) can be selected, there are the following problems.

In the valve control method, the change in the turning speed is small, and in the rotation speed control method, the change in the pump discharge amount (= speed change) is large with respect to the change in the engine speed.

Therefore, for example, when turning is started, the valve control system has poor acceleration performance, and the rotation speed control system causes a sharp turn, so that proper control cannot be performed depending on the work contents, or control according to operator preference. There were times when you could not.

Since delicate acceleration / deceleration control (fine speed control) such as a follow-up operation when a load shakes during turning is possible only by a valve control system with a small speed change,
If it becomes necessary to control the speed at a low speed during the rotation speed control, it is necessary to adjust the engine rotation speed appropriately and then perform a troublesome operation such as switching to the valve control system, resulting in poor operability. It was

As shown in Japanese Utility Model Laid-Open No. 3-49291, there is known a swing control device in which a constant discharge amount control for maintaining a constant pump discharge amount is added to a control pattern regardless of a change in engine speed. Has become.

However, according to this configuration, the turning speed does not change even if the engine speed changes during the valve control, so that the stability of the valve control is improved.
The above problems still remain.

Therefore, the present invention provides a turning control device for a working machine capable of improving control performance and operability.

[0010]

According to a first aspect of the present invention, there is provided a variable displacement hydraulic pump driven by an engine, a regulator for adjusting a flow rate of the hydraulic pump, and a swing motor having the hydraulic pump as a hydraulic source. , A swing control valve that controls the rotation direction and speed of this swing motor,
An engine speed detecting means for detecting the speed of the engine, a controller for outputting a command signal of a pump discharge amount to the regulator according to the engine speed detected by the engine speed detecting means, and an output of the controller A control mode setting device for selecting and issuing a command from a plurality of types of patterns having different rates of change in pump discharge amount with respect to changes in engine speed is provided.

According to a second aspect of the invention, in the configuration of the first aspect, a switch is provided between the controller and the control mode selector to connect or disconnect them.

According to a third aspect of the present invention, a variable displacement hydraulic pump driven by an engine, a regulator for adjusting a flow rate of the hydraulic pump, a swing motor using the hydraulic pump as a hydraulic source, and a rotation of the swing motor. A swing control valve for controlling the direction and speed, an engine speed detecting means for detecting the engine speed, and a rate of change of the pump discharge amount according to the engine speed detected by the engine speed detecting means. And a controller that outputs a command signal to the regulator.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the controller is configured to output a command signal for increasing the rate of change of the pump discharge amount with an increase in the engine speed. .

[0014]

According to the present invention, the control mode setting unit arbitrarily selects the rate of change of the pump discharge amount with respect to the change of the engine speed, that is, the control pattern of the rotational speed control method from a plurality of types. be able to.

Therefore, the optimum control performance can be obtained according to the work content, operator preference, and the like.
Fine speed control by the rotation speed control method is possible by setting the pattern.

According to the second aspect of the present invention, the operator can intentionally cancel the control pattern selection function by turning off the switch, and switch to the rotation speed control system for only one pattern.

On the other hand, according to the third and fourth aspects of the invention, since the rate of change of the pump discharge amount changes depending on the engine speed, it is possible to perform fine speed control of the turning speed in the engine speed range where the change of the pump discharge amount is small. Become. In addition, the turning acceleration performance is good in the engine speed range where the change in the pump discharge amount is large.

In this case, according to the fourth aspect of the invention, the rate of change of the pump discharge amount increases with the increase of the engine speed, so that, for example, at the start of turning, in the low speed range where the change of the discharge amount is small in the rising section. By setting and moving to a high-speed range where the discharge rate changes greatly after the start of turning, smooth start-up and acceleration are possible and control performance is improved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the circuit configuration and block configuration of this turning control device.

In the figure, 11 is an engine, 12 is a variable displacement hydraulic pump driven by the engine 11, and 13 is a variable displacement hydraulic pump.
Is a swing motor, 14 is a swing control valve for controlling the rotation direction and speed of the swing motor 13, and 15 is a relief valve.

The hydraulic pump 12 comprises an electromagnetic proportional pressure reducing valve (hereinafter simply referred to as pressure reducing valve) 17 to which a primary pressure is supplied from an auxiliary hydraulic power source 16 and an actuator 18 driven by the secondary pressure of the pressure reducing valve 17. The regulator 19 adjusts the flow rate (absorption amount per one rotation of the pump), and thereby the pump discharge amount is controlled.

Further, a pump discharge amount command signal (control current) from the controller 20 is sent to the electromagnetic operating portion 17a of the pressure reducing valve 17, and the secondary pressure is proportional to the control current I as shown in FIG. (Drive pressure of the actuator 18) changes, and as shown in FIG. 3, the pump absorption amount q changes in proportion to this secondary pressure. Therefore, the relationship between the control current I and the pump absorption amount q is as shown in FIG.

The controller 20 outputs a control current I according to the engine speed based on a signal from the engine speed sensor 21 which detects the engine speed of the engine 11.

The controller 20 has a switch 22.
The control mode setting device 23 is connected via
When the control mode setting device 23 is operated from the outside while 2 is on, the output pattern of the controller 20 causes the control current I to decrease as the engine speed n increases as shown in FIG. It is a pattern and is selected from three types of patterns a, b, and c in which the rate of change of the control current I is different.

Explaining this point in detail, the discharge amount of the pump 12 is Q (cc / min), the engine speed is n (rpm), the pump absorption amount is q (cc / rev), and the control current of the pressure reducing valve 17 is I
Assuming (A), q = a × I + b and I = c / n + d (where a, b, c, and d are constants).

[0026]

## EQU1 ## Q = n × q = n × (a × I + b) = n × {a × (c / n + d) + b} = a × c + n × (a × d + b)

Therefore, the engine speed / control current characteristic, that is, the rate of change of the control current with respect to the engine speed is determined by setting the values of the constants a to d.

Therefore, three types of characteristics having different values of the constants (for example, c and d) are input to the control mode setting unit 23 in advance, and one of them is selected from the outside by operating, for example, a selection switch. , Output patterns of the controller 20 are three types of pattern a in which the rate of change of the control current I with respect to the change of the engine speed n is
It is configured to be selected from b and c.

As a result, the engine speed / pump discharge amount characteristic is arbitrarily selected from among a ', b', and c'in FIG.

When the switch 22 is off, the control pattern selecting function is canceled.
At this time, the controller 20 performs a constant current operation, that is, an operation of keeping the control current constant regardless of the change in the engine speed as shown by the dotted line in FIG.
The pump discharge amount characteristic is as shown by the dotted line in FIG.

As described above, the control pattern for the rotation speed control can be arbitrarily selected from among three types, i ', b', and c '(4 types if the switch 22 is turned off). Appropriate control can be performed with a pattern suitable for the operator's preference.

For example, in the initial stage of turning start, a control pattern c'having a small change rate is selected to be smoothly started, and thereafter, a control pattern c'having a large change rate is switched to efficiently accelerate the steady state. When the speed is reached, a control function suitable for the turning motion can be obtained, such as shifting to a control pattern B having an intermediate change rate.

Further, when it is desired to perform fine speed control for follow-up operation or the like when a load sway occurs during turning, a control pattern ha 'having a small change rate is selected, so that the rotation which has been impossible in the past can be achieved. Fine speed control can be achieved by the number control method.

That is, the fine speed control can be performed by either the valve control system or the rotation speed control system. Therefore, it is not necessary to switch to the valve control system in order to perform the fine speed control during the turning in the rotation speed control system as in the conventional case, and the operability is improved.

Other Embodiments (1) In the above embodiment, based on the characteristic that the pump absorption amount q increases in proportion to the increase of the control current I as shown in FIG.
As shown in FIG. 5, the controller output pattern to be selected is selected from among three patterns a, b, and c in which the control current I decreases as the engine speed n increases. On the contrary, as shown in FIG.
The pump absorption amount q decreases in inverse proportion to the increase in the engine speed n, and based on this, as shown in FIG.
Output pattern i in which the control current I increases with an increase in
It may be configured so as to obtain b and c.

(2) The controller output patterns that can be selected by the control mode setting unit 23 are not limited to the three patterns (a), (b) and (c) in FIG. 5, and may be two or four or more.

(3) Instead of the configuration in which the output pattern of the controller 20 is selected from a plurality as described above, the relationship between the engine speed n and the pump discharge amount Q is as shown in FIG.

[0038]

[Equation 2]

That is, the relationship between the engine speed n and the control current I may be set so that the pump discharge amount Q is a high-order expression of the engine speed n.

In this way, the pump discharge amount Q will increase in an accelerated manner as the engine speed n increases (the rate of change of the pump discharge amount Q continuously changes depending on the engine speed n).

According to this structure, since the change in the pump discharge amount Q is small in the low speed region of the engine rotation, the fine speed control of the turning speed becomes possible, and the change in the pump discharge amount Q becomes large in the high speed region of the engine rotation. The turning acceleration performance is good.

Further, at the time of starting the turning, the turning operation is set to a low speed range where the discharge amount is small in the rising section, and after the turning is started, the speed is changed to a high speed range where the discharge rate is greatly changed, so that the turning operation is smooth and efficient. It will be possible.

[0043]

As described above, according to the first and second aspects of the present invention, the output pattern of the controller for outputting the command signal of the pump discharge amount to the regulator according to the engine speed is set by the control mode setting device. Since the configuration is such that it can be arbitrarily selected from a plurality of types with different rates of change in pump discharge rate with respect to changes in rotational speed, it is possible to obtain optimum control performance according to work content and operator preference, and to set pattern settings. Thus, it becomes possible to perform fine speed control by the rotation speed control method. Therefore, control performance and operability can be improved.

According to the second aspect of the present invention, the operator can intentionally cancel the control pattern selecting function by turning the switch off, and switch to the rotational speed control system of only one pattern.

On the other hand, according to the third aspect of the present invention, the rate of change of the pump discharge amount changes depending on the engine speed.
It becomes possible to perform fine speed control of the turning speed in the engine speed range in which the change in the pump discharge amount is small. In addition, the turning acceleration performance is good in the engine speed range where the change in the pump discharge amount is large.

In this case, according to the fourth aspect of the present invention, the rate of change of the pump discharge amount increases as the engine speed increases. By setting and moving to a high-speed range where the discharge rate changes greatly after the start of turning, smooth start-up and acceleration are possible and control performance is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a hydraulic circuit configuration of a turning control device according to an embodiment of the present invention together with a block configuration.

FIG. 2 is a diagram showing a relationship between a control current and a secondary pressure of the electromagnetic proportional pressure reducing valve in the embodiment.

FIG. 3 is a diagram showing a relationship between a secondary pressure of the pressure reducing valve and a pump absorption amount.

FIG. 4 is a diagram showing a relationship between the control current and a pump absorption amount.

FIG. 5 is a diagram showing a relationship between an engine speed and a control current in the embodiment.

FIG. 6 is a diagram showing a relationship between the engine speed and a pump discharge amount.

FIG. 7 is a diagram showing a relationship between a control current of a solenoid proportional pressure reducing valve and a pump absorption amount in another embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between an engine speed and a control current in the embodiment.

FIG. 9 is a diagram showing a relationship between an engine speed and a pump discharge amount in still another embodiment of the present invention.

FIG. 10 is a diagram showing a conventional configuration.

[Explanation of symbols]

 Reference Signs List 11 engine 12 variable displacement hydraulic pump 13 swing motor 14 swing control valve 19 regulator 17 electromagnetic proportional pressure reducing valve that constitutes a regulator 18 same actuator 20 controller 21 rotation speed sensor (rotation speed detection means) 23 control mode setter 22 switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F15B 11/04

Claims (4)

[Claims] 1. A variable displacement hydraulic pump driven by an engine, a regulator for adjusting a flow rate of the hydraulic pump, a swing motor using the hydraulic pump as a hydraulic source, and a rotation direction and a speed of the swing motor. Turning control valve, an engine speed detecting means for detecting the engine speed, and a controller for outputting a command signal of a pump discharge amount to the regulator according to the engine speed detected by the engine speed detecting means. And a control mode setting device that selects and commands an output pattern of this controller from a plurality of types of patterns having different rates of change in pump discharge amount with respect to changes in engine speed. Turning control device. 2. The swing control device for a working machine according to claim 1, further comprising a switch provided between the controller and the control mode selector for connecting and disconnecting them. 3. A variable displacement hydraulic pump driven by an engine, a regulator for adjusting a flow rate of the hydraulic pump, a swing motor using the hydraulic pump as a hydraulic source, and a rotation direction and a speed of the swing motor. Turning control valve, an engine speed detecting means for detecting the engine speed, and a command signal for changing the rate of change of pump discharge amount according to the engine speed detected by the engine speed detecting means. A turning control device for a working machine, comprising: 4. The swing control of a work machine according to claim 3, wherein the controller is configured to output a command signal for increasing the rate of change of the pump discharge amount with an increase in the engine speed. apparatus.