JP3027531B2 - Turning control circuit for construction machinery, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of a turning control circuit for a construction machine or the like.

[0002]

2. Description of the Related Art Various types of drive circuits have been proposed for controlling the turning of an upper turning body of a construction machine. For example, Japanese Unexamined Patent Publication No. Hei 6-117406 discloses a drive circuit that prevents a sudden acceleration of a rotational load during startup. Also, Japanese Patent Laid-Open Publication No. Hei 6-117407.
No. 6-123303 discloses a hydraulic control device for driving a hydraulic motor and a hydraulic cylinder by connecting them in parallel. The control circuit for the revolving superstructure shown in FIG. 5 is a conventional device which is considered to be closest to the present invention. Hereinafter, the circuit of FIG. 5 will be described.

In FIG. 5, a hydraulic pump 1 having a variable discharge amount is shown.
And the oil tank 2 are connected by a main oil passage 3. A direction switching valve 4 is inserted in the main oil passage 3. A hydraulic motor 5 for driving the upper swing body 7 is connected to a secondary port of the direction switching valve 4 by an oil passage 6. One of the primary ports of the direction switching valve 4 is connected to the oil tank 8, and the other primary port is connected to the main oil passage 3 through a check valve 9.
It is connected to the. The hydraulic pump 1 is connected to a power source 10 such as an engine, and is also connected to a regulator 11 for adjusting a discharge amount.

The regulator 11 is composed of two connected chambers, and is divided into four small oil chambers 11a, 11b, 11c and 11d by an H-shaped piston 12. The left end of the piston 12 is connected to a rod 13,
Is connected to a swash plate that changes the discharge amount of the hydraulic pump 1. The hydraulic pump 1 is configured such that the discharge amount increases when the rod 13 moves in the direction of arrow I and decreases when the rod 13 moves in the direction of arrow D. Also, the first oil chamber 11a
A spring 14 is provided inside the H-shaped piston 1.
2 is pressed to the right. The second oil chamber 11b is connected by a branch oil passage 15 branched from the oil passage 3 downstream of the hydraulic pump 1.

When the discharge pressure of the hydraulic pump 1 increases, the branch oil passage 15 presses the H-shaped piston 12 in the direction of arrow D to decrease the discharge amount. Conversely, when the discharge pressure decreases, the pressure is pressed in the direction of arrow I to increase the discharge amount. That is, the branch oil passage 15 keeps the discharge horsepower substantially constant.
Further, the fourth oil chamber 11 d is connected to a secondary port of the electromagnetic switching valve 17 by an oil passage 16. 4th oil chamber 11d
When the pressurized oil is supplied, the H-shaped piston 12 and the rod 13 are pressed in the direction of arrow D, and the discharge amount or discharge horsepower is limited by that amount and decreases. The first oil chamber and the third oil chamber are connected to an oil tank 18.

The primary port of the electromagnetic switching valve 17 is connected to a pilot hydraulic pump 18 and an oil tank 19, respectively. The solenoid 17s of the electromagnetic switching valve 17 is connected to a control current output terminal of the controller 20. The controller 20 outputs “1” or “0” as the control current. When “1” is output as the control current, the electromagnetic switching valve 17 enters the state b, the oil passage 16 and the pilot hydraulic pump 18 are connected, the pilot hydraulic pressure is supplied to the fourth oil chamber 11d, and the hydraulic pump 1 discharges. Horsepower is limited to small horsepower. Conversely, when the control current is "0", the oil passage 16 and the oil tank 19 are connected, so that the discharge horsepower is not limited, and the horsepower is large.

FIG. 6 shows the discharge pressure P and discharge amount Q of the hydraulic pump 1.
FIG. A curve A represents a relationship between the discharge pressure and the discharge amount in the steady state when the horsepower is large, that is, when the control current is “0”, and is substantially a hyperbola. The discharge pressure P1 is a set pressure, and P1
Since the relief valve (not shown) opens at the above pressure, the supply hydraulic pressure does not exceed P1. Starting from the state of S1, the state of S2 is reached. In state S2, the discharge pressure is P1 and the discharge amount is Q1. While the hydraulic motor 5 is stationary or rotating at a slow speed, the flow path resistance is large and remains in the state S2. As the rotation speed increases, the flow path resistance decreases, and the discharge amount Q increases to increase the maximum discharge amount. Qm. On the other hand, the discharge pressure P decreases, and the state moves in the direction of S3. Curve B is a diagram showing the relationship when the horsepower is small, that is, when the control current is "1".

FIG. 7 is a diagram showing characteristics of the hydraulic motor 5. Hereinafter, the output horsepower of the hydraulic pump 1 is large horsepower (A in FIG. 6).
(Curve) will be described. Curve C shows the characteristics when the moment of inertia of the load is large. At the start stage, the turning drive pressure p rises linearly to P1, and until the turning speed reaches a certain value (until time t1), the inertia resistance is large, so that the turning drive pressure remains at P1. When the turning speed v exceeds the above value (after time t1), the inertial resistance decreases, and the turning drive pressure p gradually decreases. On the other hand, the turning speed gradually increases as shown by the lower curve c because the moment of inertia is large, and reaches the maximum turning speed.

Curves D and d show characteristics when the load is small. In this case, the turning drive pressure remains at P1 for a short time (until time t2), but immediately begins to drop. Also,
As shown by the curve d, the turning speed also increases in a short time and reaches the maximum turning speed. Note that the output horsepower is small horsepower (B in FIG. 6).
The characteristic of the hydraulic motor in the case of (curve) is a characteristic curve having a shape in which the time axis is extended in the graph of FIG.

This turning control circuit is configured as described above, and operates as follows. That is, when the operation lever (not shown) is operated to the forward rotation side, the direction switching valve 4 is connected to the oil passage of the portion a with each port, and the pressure oil from the hydraulic pump is supplied to the main oil passage 3 and the check valve 9. , Through the directional control valve 4, the hydraulic motor 5 flows from left to right,
The oil flows through the oil passage 6 and the direction switching valve 4 to the oil tank 8. As a result, the hydraulic motor 5 and the upper swing body 7 rotate forward. When the operation lever is operated in the reverse rotation side, the oil passage of the portion b is connected to the port, and the pressure oil flows from the right side to the left side and rotates in the reverse direction.

In this case, if the control current from the controller 20 is set to "0", the hydraulic pump 1 outputs a large horsepower as described with reference to FIG. In addition, the characteristics of the hydraulic motor operate according to the characteristic curve described with reference to FIG. When the control current is “1”, a small horsepower is output. That is, when the control current is “0” and the work implement has a large moment of inertia as shown in FIG. 8A, the work implements operations as shown by curves C and c in FIG. When the moment of inertia is small as in B), the operation is performed as shown by curves D and d in FIG. When the control current is "1", the operation is such that the time axis of these operations is extended.

[0012]

As described above,
Fig. 7 when the output horsepower is large and the moment of inertia is small
Since the turning speed reaches almost the maximum in a short time as shown by the d-curve, for example, when the working machine is to be turned 90 degrees or 180 degrees, considerable skill and labor are required to stop at the target position. Conversely, if the operation is performed with small horsepower, when the moment of inertia is large, there is a problem that it takes too much time to turn to the target value. In addition, there is a problem that the operation becomes complicated when switching between large horsepower and small horsepower while operating while checking the state of the working machine. SUMMARY OF THE INVENTION It is an object of the present invention to provide a swing control circuit that automatically measures the magnitude of the moment of inertia and facilitates a swing operation.

[0013]

According to a first aspect of the present invention, there is provided a swing control circuit comprising: a directional control valve inserted in a main oil passage connecting a variable discharge hydraulic pump and an oil tank; A swing motor for a construction machine or the like comprising a hydraulic motor for driving an upper swing body connected to the direction switching valve, a regulator for adjusting the discharge amount of the hydraulic pump, an electromagnetic valve for controlling the regulator, and a controller for controlling the electromagnetic valve. The circuit includes a calculating means for calculating a moment of inertia from data from an angle sensor of an interference prevention circuit of the working machine provided on the upper rotating body and predetermined data on the working machine, and the calculating means calculates the moment of inertia. The electromagnetic valve is controlled so that the swing speed of the upper swing body becomes a predetermined speed based on the moment of inertia. This device measures the current moment of inertia of the working machine by means of moment of inertia measurement, controls the solenoid valve, adjusts the hydraulic pressure to the regulator, thereby limiting the output horsepower of the hydraulic pump, and the turning speed of the hydraulic motor. Control.

[0014] The turning control circuit according to claim 2 is
The electromagnetic valve according to claim 1 is constituted by a proportional-type electromagnetic pressure reducing valve. This device uses the means for measuring the moment of inertia as a sensor used in the interference prevention circuit of the work machine, and uses a proportional type electromagnetic pressure reducing valve as the solenoid valve to linearize the control. Simplified.

[0015]

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 shows the configuration of Embodiment 1 of the present invention. In FIG. 1, the same components as those described in the conventional example (FIGS. 5 to 8) are denoted by the same reference numerals, and detailed description is omitted.
In FIG. 1, a work machine 30 provided on the upper swing body 7 includes a boom angle sensor 35 and an offset angle sensor 3.
4. The arm angle sensor 33 is attached. The measurement data of these sensors 33 to 35 is taken into the controller 32. The controller 32 determines a control current to be passed to the proportional solenoid valve 31 from these data, and outputs it as a solenoid current. The sensors 33 to 3
The measurement data of No. 5 may use data used for preventing interference of the working machine.

FIG. 2 shows the configuration of the controller 32. The controller 32 includes a CPU (Central Processing Unit), a RAM memory, a ROM memory, and the like. In FIG.
Data detected by the angle sensors 33 to 35 are recorded in the memory 39 via A / D converters 36 to 38.
In the memory 40, length data, center of gravity position data, mass data, and the like of the boom and the arm of the working machine are recorded. The calculation unit 41 obtains a moment of inertia value of the upper swing body 7 and the work implement 30 or a value related thereto from the data recorded in the memories 39 and 40. Examples of a method for obtaining this value will be described in the following first and second embodiments. The calculation by the controller 32 may be performed for each cycle by time shearing, or may be started when the operator grips the turning operation lever.

[0018]

Embodiment 1 Since the moment of inertia of the upper swing body 7 is invariable, it is determined in advance. This value is defined as Ju. When the boom angle S1, the offset angle S2, and the arm angle S3 are set, the lengths of the boom, the offset arm, and the arm,
Since the position of the center of gravity and the mass are recorded in the memory 40 and are known, the moment of inertia Js of the working machine is calculated from these data. The sum of Ju and Js (or the resultant vector) gives the moment of inertia Jt sought.

[0019]

[Embodiment 2] The required moment of inertia Jt is changed to the boom angle S.
1, a function J (S) of the offset angle S2 and the arm angle S3
1, S2, and S3), and a three-dimensional table of Jt is created in advance for each value of S1, S2, and S3 by experiment or calculation. Given data S1, S2, S3
Jt is determined from the table.

Next, the control signal generation section 42
A control signal having a magnitude inversely proportional to Jt is generated on the basis of the data obtained in step (1), and output to the driver 43. The output current of the driver 43 flows to the solenoid of the proportional solenoid valve 31, and pressure oil proportional to the solenoid current flows from the pilot pump 18 to the oil passage 16. This pressure oil operates the regulator 11 and controls the output horsepower of the hydraulic pump 1 as described in the conventional example.

The first embodiment operates as follows because it is configured as described above. For example, when the operator grips the turning operation lever, the calculation start signal is sent to the controller 32.
Is sent to the controller 32 and the current angle data S
1, S2, and S3 are read from the memory 39, the moment of inertia is calculated, and a control signal corresponding to the moment value is generated. This control signal is sent to the proportional solenoid valve 31 via the driver 43.

When the moment of inertia is large, the oil pressure flowing through the oil passage 16 becomes small. Conversely, when the moment of inertia is small, the hydraulic pressure increases. Therefore, the smaller the determined moment of inertia is, the more the H-shaped piston 12 is pressed to the left, and the smaller the discharge horsepower of the hydraulic pump 1 is. As a result, much time is required until the swing body 7 reaches the maximum swing speed, and the operation becomes easy. One example of the characteristics of the hydraulic motor according to the first embodiment is shown by curves E and e in FIG.

As described above, the first embodiment has an effect that the operation is easy regardless of the magnitude of the moment of inertia of the working machine. In addition, data of the angle detection sensor used in the interference prevention circuit of the work machine can be used, and it is not necessary to provide a special device.

Embodiment 2 FIG. 3 shows the configuration of Embodiment 2 of the present invention. In FIG. 3, the same components as those described in the conventional example (FIGS. 5 to 8) and the first embodiment are denoted by the same reference numerals, and detailed description is omitted. In FIG. 3, data of a speed sensor 45 provided at an appropriate position near the revolving superstructure 7 is taken into the controller 46. The controller 46 outputs a control current to the proportional solenoid valve 31.

FIG. 4 shows the configuration of the controller 46. In FIG. 4, the measurement data from the speed sensor 45 is A / D
The data is recorded in the memory 48 via the converter 47. On the other hand, in the memory 49, a preferable turning speed of the upper turning body is recorded as a target value. This target turning speed may be a constant value or a value that changes with time. The arithmetic unit 50 calculates a deviation value by subtracting the data value of the memory 48 from the data value of the memory 49, and outputs the deviation value to the control signal generation unit 51. The control signal generator 51 reduces the minute current proportional to the deviation value from the current signal current value, and outputs it to the driver 52 as a new signal current value. The driver 52 outputs the new signal current to the solenoid of the proportional solenoid valve 31.

Since the second embodiment is configured as described above, it operates as follows. That is, when the speed data is sent from the speed sensor 45 to the controller 46, the controller 46 compares the actual speed data with the target speed data, and when the actual speed data is small (the deviation is negative), the signal current is reduced. When the actual speed data is large (when the deviation is positive), the signal current is increased and the signal current is output to the proportional solenoid valve 31. The proportional solenoid valve 31 increases or decreases the oil pressure supplied to the oil passage 16 in proportion to the signal current.

When the deviation is negative, the pressure oil in the fourth oil chamber falls, the H-type piston moves in the I direction, and the output horsepower of the hydraulic pump 1 increases. Therefore, the turning speed of the upper turning body 7 increases. When the deviation is positive, the output horsepower decreases,
The turning speed decreases. By the above operation, the upper swing body 7
Is equal to the target turning speed recorded in the memory 49.

If the target turning speed is set to an appropriate value (or a function value that changes with time), a predetermined turning speed can be obtained irrespective of the magnitude of the moment of inertia of the working machine, so that the turning operation can be easily performed. There is an effect of becoming.

Although the embodiments and examples of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the above-described or exemplified ones, and does not depart from the gist of the present invention. Even if there is a change in the design, etc., this invention is included. For example, the solenoid valve 31 is not limited to a proportional solenoid valve, but may be an inverse proportional solenoid valve. Of course, in this case, the operation of the control signal generator is different. It is not necessary to directly obtain the value of the moment of inertia, but it is also possible to obtain and control a value related thereto. Further, the method of calculating the moment of inertia and a value related thereto is not limited to the method described in the embodiment.

[0030]

As described above, according to the present invention,
There is an effect that the turning operation becomes easy regardless of the state of the work machine.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram of a controller according to the first embodiment.

FIG. 3 is a diagram showing a configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram of a controller according to a second embodiment.

FIG. 5 is a diagram showing a configuration of a conventional device.

FIG. 6 is a diagram showing output horsepower of a hydraulic pump.

FIG. 7 is a diagram showing characteristics of a hydraulic motor.

8A is a diagram showing a case where the moment of inertia of the work implement is large, and FIG. 8B is a diagram showing a case where the moment of inertia is small.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Oil tank 3 Main oil path 4 Direction switching valve 5 Hydraulic motor 7 Upper revolving unit 10 Prime mover 11 Regulator 30 Work machine 31 Proportional electromagnetic pressure reducing valve (electromagnetic valve) 32, 46 Controller 33 Arm angle sensor 34 Offset angle sensor 35 Boom angle sensor

Claims (2)

(57) [Claims] 1. A directional control valve interposed in a main oil passage connecting a variable discharge hydraulic pump and an oil tank, a hydraulic motor driving an upper revolving unit connected to the directional control valve, and a discharge amount of the hydraulic pump. In a swing control circuit for a construction machine or the like comprising a regulator for adjusting the pressure, a solenoid valve for controlling the regulator, and a controller for controlling the solenoid valve, the angle of the work machine interference prevention circuit provided on the upper swing body is controlled by an angle sensor. Calculating means for calculating a moment of inertia from the data and predetermined data relating to the working machine; and the electromagnetic means is arranged such that the turning speed of the upper-part turning body becomes a predetermined speed based on the moment of inertia obtained by the calculating means. A turning control circuit for a construction machine or the like, wherein the valve is controlled. 2. A turning control circuit for a construction machine or the like, wherein the solenoid valve comprises a proportional solenoid pressure reducing valve.