JPH10141308A - Hydraulic circuit device for driving revolving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain shock and vibration from generating on a revolving body when it starts and stops without lowering energy consumption efficiency or changing revolving speed when the working radius becomes small. SOLUTION: A control device 30 calculates the working radius of a working machine by taking in detection signals of a boom angle and an arm angle and makes a proportional control cylinder 8 adjust the inclined rotation angle of a revolving motor 5 by outputting a motor inclined rotation control signal Mc corresponding to the working radius to a proportional solenoid valve 9. A pump inclined rotation control signal Pr giving the maximum inclined rotation angle of a hydraulic pump 1 corresponding to the inclined rotation angle of the revolving motor 5 is outputted to a proportional solenoid valve 9 and the maximum control value of the hydraulic pump 1 inclined rotation angle caused by an inclined rotation control piston 61 of the proportional control limitation cylinder 6 is limited by the displacement of a maximum inclined rotation quantity limitation piston 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a hydraulic circuit device for driving a swinging body of a construction machine such as a hydraulic shovel in which a swinging motor is driven by a swing motor.

[0002]

2. Description of the Related Art A revolving structure such as a hydraulic excavator or a hydraulic crane has a large inertia, and in order to efficiently drive the revolving structure, a maximum pressure regulating valve (relief) for regulating the maximum pressure of a revolving motor drive hydraulic circuit is required. The set pressure of the valve is generally set to a high pressure. Therefore, a large inertial load is temporarily applied to the swing motor when the swing body starts and stops, and a large impact or vibration may be generated on the swing body. The impact and vibration generated in the revolving unit depend on the rotational moment of the working unit mounted on the revolving unit. For example, the turning radius of the working unit up to the tip of the working unit when the boom extends and contracts in the horizontal direction (hereinafter referred to as the working radius) When the boom stands up in the vertical direction and the rotational moment is small, the impact and vibration tend to be greater than when the radius is large, that is, when the rotational moment is large.

In order to solve such a problem, Japanese Unexamined Patent Publication No.
According to the invention described in JP-A-173299, the set pressure of the maximum pressure regulating valve provided in the turning motor drive hydraulic circuit is changed according to the working radius, and when the working radius is small, the set pressure of the maximum pressure regulating valve is set low. Control. By performing such control, it is possible to reduce the impact and vibration generated on the revolving structure when the working radius is small, but the setting pressure of the maximum pressure regulating valve is set low, and the energy consumption efficiency decreases. I will.

Therefore, a turning motor, for example, is used as a hydraulic circuit configuration that suppresses the generation of shocks and vibrations that occur on the turning body when starting and stopping with a small working radius without reducing the energy consumption efficiency. It is conceivable to use a variable displacement motor as disclosed in Japanese Utility Model Laid-Open Publication No. 6-53657 to control the tilt angle of the turning motor in accordance with the working radius.

[0005]

With the above-described hydraulic circuit configuration, when the working radius is reduced, control is performed so that the tilt angle of the swing motor is reduced, thereby reducing the rotational force of the swing motor. By lowering it, it is possible to suppress the occurrence of shocks and vibrations that occur in the revolving superstructure at the time of starting and stopping. However, when the tilt angle of the swing motor is reduced by the above control, the rotation force of the swing motor can be reduced, but the rotation speed of the swing motor increases due to the supply of a constant flow of hydraulic oil from the hydraulic pump. Then, the revolving superstructure rotates faster.

For example, when the excavator lifts and turns the excavated earth and sand to excavate a gutter, the excavation position changes when the excavator performs an operation of dumping the earth on the bed of a dump truck waiting at a predetermined position. When the distance from the turning center changes, the turning speed changes as described above, and therefore, the operation operation becomes uncomfortable for the operator. In particular, when the work radius at the excavation position is large and the work radius at the standby position of the dump truck is small, even when the operator operates the turning operation rod with the same operation amount, when the bucket is near the excavation position, The revolving body slowly turns, and when approaching the vicinity of the unloading position close to the center of turning, turns sharply and quickly, giving the operator an uneasy feeling. The present invention has been made in view of such circumstances in the prior art, and does not reduce the energy consumption efficiency, and does not change the turning speed when the working radius is reduced, at the time of startup or stop. It is an object of the present invention to provide a revolving unit drive hydraulic circuit device capable of suppressing the generation of impact and vibration generated in the revolving unit.

[0007]

According to the present invention, in order to solve the above-mentioned problems, a hydraulic pump and a swing motor are of variable capacity, and a distance between a tip of a working machine mounted on a swing body and a swing center is provided. Measuring means for measuring a working radius, a first control means for controlling a tilt angle of the turning motor according to the working radius measured by the measuring means, and a control means for controlling the first control means. Second control means for controlling the tilt angle of the hydraulic pump so as to limit the maximum value of the flow rate of the hydraulic oil flowing into the swing motor, and preferably,
The second control means limits the maximum value of the control amount of the tilt angle control means for controlling the tilt angle of the hydraulic pump according to the discharge pressure of the hydraulic pump.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 is a hydraulic circuit diagram of a hydraulic shovel according to an embodiment of the present invention, FIG. 2 is a side view of the hydraulic shovel, and FIG. 3 is a dimensional diagram showing a relationship between a working radius and lengths and angles of components of the hydraulic shovel. It is. In these figures, 1 is a hydraulic pump connected to a prime mover (not shown), 2 is a direction switching valve for switching a supply direction and a supply amount of discharge oil of the hydraulic pump 1 to a later-described turning motor, and 3 is an oil for storing hydraulic oil. The tank 4 is a pilot hydraulic pump that is a supply source of pilot oil, which is a pressure transmission medium of the command system, and the swing motor 5 that swings a swing body described later.

A proportional control limit 6 controls the tilt angle of the hydraulic pump 1 according to the discharge pressure of the hydraulic pump 1 and limits the maximum tilt angle of the hydraulic pump 1 according to the working radius of the hydraulic shovel. cylinder, 7 is driven by a pump tilting limit signal P _R in accordance with the operating radius, performs intermittent supply to the oil chamber for the maximum tilt angle limit of the proportional control cylinder 6 of the pilot oil from the pilot hydraulic pump 4 proportional solenoid valve, the proportional control cylinder for controlling a tilting angle of the turning motor 5 8, 9 is driven by a motor displacement control signal M _C in accordance with the working radius, the pilot oil of the proportional control cylinder from the pilot hydraulic pump 4 8 is a proportional solenoid valve for interrupting the supply to 8, 10 is a maximum pressure regulating valve for regulating the maximum discharge pressure of the hydraulic pump 1, and 11 and 12 are inflow and outflow connected to the turning motor 5, respectively. Is connected between line T _1, T _2, in response to pressure or more hydraulic place of one line T ₁ or other conduit T in ₂ to open, one of the inlet exit conduit T _1, T ₂ It is a maximum pressure regulating valve that regulates the maximum hydraulic pressure in the inside.

Reference numeral 13 denotes a small gear connected to the rotating shaft of the turning motor 5, 14 denotes a turning body to which the turning motor 5 is fixed,
Reference numeral 15 denotes a rack formed on an inner surface of a support cylinder of the traveling body to be described later rotatably supporting the revolving body 14 and meshes with the small gear 13. Reference numeral 16 denotes a traveling body that rotatably supports the revolving body 14 described above. Is a crawler belt that runs over a driving wheel (not shown) of the traveling body 16 and runs on the ground GL, 18 is a boom driving cylinder, 19 is a boom rotatably supported by the revolving unit 14, 20 is an arm driving cylinder, 21 Is boom 19
, 22 is a bucket driving cylinder, and 23 is a bucket rotatably supported by the arm 21. Reference numeral 25 denotes a boom angle sensor that is installed at the pivot of the boom 19 to detect the elevation angle of the boom 19;
An arm angle sensor 30 for detecting a forward rotation angle with respect to the vertical direction 1 is a control device for controlling the entire hydraulic excavator.

Further, a tilt control piston 61 is biased rightward in FIG. 1 by a spring and moves left and right to change the tilt angle of the hydraulic pump 1. A 62 is also biased rightward by a spring. The maximum displacement limiting piston 63 restricts the rightward movement of the tilt control piston 61 by moving to the left and right, and a proportional control 63 in which the discharge oil of the hydraulic pump 1 flows in and presses the tilt control piston 61. One oil chamber 64 of the restriction cylinder 6 is the other oil chamber of the proportional control restriction cylinder 6 in which the pilot oil flowing out of the proportional solenoid valve 7 flows in and pushes the maximum displacement limiting piston 62 to the left.

The pivot 21 of the boom 19 and the arm 21
L ₁ , the distance between the rotation fulcrum of the arm 21 and the center of gravity of the bucket 23 is L ₂ , the working radius of the working machine is L, and the contribution to the working radius L of the boom 19 is L 1. L ₁ , the contribution of the arm 21 and the bucket 23 to the working radius L is l ₂ , the elevation angle of the boom 19, ie, the boom angle α, the forward rotation angle of the arm 21 with respect to the vertical direction, ie, the arm angle Is β. As shown in FIG. 2, the hydraulic excavator moves the crawler belt 17 around the traveling body 1.
6 can be moved in the front and rear direction, and the boom drive cylinder 1
8. The working machine bends and expands by the expansion and contraction of the arm driving cylinder 20 and the bucket driving cylinder 22 to realize a desired posture and movement trajectory of the bucket 23. Of course, the operation of each actuator is controlled. Although the hydraulic circuit mechanism including the respective directional control valves is provided, these structures have no direct relation to the content of the present invention, so that illustration and description thereof are omitted.

Next, the operation of this embodiment will be described. When the operator operates the turning operation rod, the direction switching valve 2 is switched to one of the left and right switching positions, and the discharge oil of the hydraulic pump 1 is transferred to one of the conduits T ₁ and T ₂ via the direction switching valve 2. And then into the turning motor 5 to rotate it. Due to the rotation of the swing motor 5, the small gear 13 and the rack 15 meshing therewith rotate in the same direction, and the swing body 14 starts to swing with respect to the traveling body 16. The control device 30 always calculates the working radius L of the working machine based on the detection signals of the boom angle α and the arm angle β output from the boom angle sensor 25 and the arm angle sensor 26, and further calculates the working radius L
After calculating the motor displacement control signal M _C for controlling the tilt angle of the pump tilting limit signal P _R and the turning motor 5 for limiting the maximum tilting angle of the hydraulic pump 1, each proportional solenoid valves 7 and 9 Output.

The proportional solenoid valves 7 and 9 are provided with a pump tilt limit signal P
It is switched depending on the value of _R and motor displacement control signal M _C, supplies the pilot oil from the pilot hydraulic pump 4 to the other oil chamber 64 and the proportional control cylinders 8 of the respective proportional control restriction cylinder 6. When the working radius L of the working machine is long, the control device 30 sends the pump tilt limit signal P
The value of _R and motor displacement control signal M _C are both large,
Accordingly, the control pressure of the proportional solenoid valves 7 and 9 so also increases, when the short working radius L of the working machine signals P _R, M _C are both small, therefore, the control pressure of the proportional solenoid valves 7 and 9 Are also controlled to be small. As a result, when the working radius L of the working machine is long, the maximum tilt angle of the hydraulic pump 1 and the tilt angle of the turning motor 5 are both large, and when the working radius L is short, the maximum tilt angle and the turning angle of the hydraulic pump 1 are small. Control is performed such that both the tilt angles of the motor 5 are reduced. Accordingly, when the working radius L is short, the maximum number of revolutions of the revolving unit 14 can be limited to a predetermined value or less while suppressing the occurrence of shock and vibration occurring on the revolving unit 14 at the time of starting and stopping. .

The details of this control will be described more specifically with reference to FIGS. FIG. 4 shows the respective contributions to the working radius L of the boom 19 and the arm 21 when the boom angle α and the arm angle β are given (actually, the boom 19
(Including the deviation L ₀ between the rotation fulcrum and the rotation center C), that is, the characteristic diagram showing the relationship between the boom working radius l ₁ and the arm working radius l ₂ , and FIG. Flow chart showing the content of control of the tilt angle of the turning motor 5;
FIG. 6 shows the turning torque T (a) with respect to the working radius L, the tilt angle q _m of the turning motor 5 with respect to the turning torque T (b), the tilt angle q _m (c) with respect to the working radius L,
FIG. 9 is a characteristic diagram showing a relationship between a maximum tilt angle q _p (d) of the hydraulic pump 1 with respect to a tilt angle q _m of the swing motor 5 and a rotary speed r _pm (e) with respect to a work radius L.

As shown in FIG. 5, first, detection signals of the boom angle α and the arm angle β output from the boom angle sensor 25 and the arm angle sensor 26 are fetched (S
1). Next, from the boom angle α and the arm angle β thus obtained, the working radius L of the working machine is calculated by the conversion curve shown in FIG. 4 according to the formula L = l ₁ + l ₂ = L ₁ cos α + L ₂ sin β + L _0. (S2). Then, the target turning torque T at this point is calculated from the characteristic curve indicating the relationship between the turning radius T and the working radius L shown in FIG. 6A (S3). Moreover, from the characteristic curve indicating the relationship between the tilting angle q _m of the turning motor 5 for pivoting torque T shown in FIG. 6 (b), calculates a tilt angle q _m of the turning motor 5 for resulting target turning torque T (S4). Then, from the characteristic curve indicating the relationship between the maximum tilt angle q _p of the hydraulic pump 1 for tilting angle q _m of the turning motor 5 shown in FIG. 6 (d), for the tilt angle q _m of the obtained turning motor 5 calculating a maximum tilt angle q _p of the hydraulic pump 1 (S5).
Thus, because the maximum tilt angle q _p of tilt angle q _m and the hydraulic pump 1 of the swing motor 5 at this time is obtained, the pump tilting limit signal P _R and motor displacement control signal based on these calculated values generates M _C, is output to the proportional solenoid valves 7, 9 (S6).

As described above, in this embodiment, the working radius L of the working machine is determined by the boom angle sensor 25 and the arm angle sensor 2.
6 based on the detection signals of the boom angle α and the arm angle β output from the boom driving cylinder 18.
In addition to the method of calculating the displacement of the arm driving cylinder 20 based on the measured displacement, the measurement may be directly performed by optical means or the like. Although the tilt angle of the hydraulic pump 1 and the swing motor 5 is controlled by the pilot pressure, the tilt angle may be directly controlled by the proportional solenoid valve. In this embodiment, the boom angle sensor 25, the arm angle sensor 26 and the control device 30 serve as measuring means, the proportional control cylinder 8, the proportional solenoid valve 9 and the control device 30 serve as first control means, and the proportional control limiting cylinder 6 , Proportional solenoid valve 7 and control device 3
0 constitutes the second control means, and the proportional control limiting cylinder 6 constitutes the tilt angle control means.

[0018]

As described above, according to the first aspect of the present invention, the hydraulic pump and the swing motor are of variable capacity, and the working radius, which is the distance between the tip of the working machine and the swing center, is measured. In addition to controlling the tilt angle of the swing motor according to this work radius and controlling the tilt angle of the hydraulic pump to limit the maximum value of the flow rate of hydraulic oil flowing into the swing motor, energy consumption efficiency is reduced. Without lowering, and
Without changing the turning speed when the working radius decreases,
It is possible to suppress the occurrence of shock and vibration generated in the revolving structure at the time of starting or stopping.

According to the second aspect of the present invention, the maximum value of the flow rate of the hydraulic oil flowing into the swing motor is limited by controlling the tilt angle of the hydraulic pump in accordance with the discharge pressure of the hydraulic pump. Since the maximum value of the control amount of the means is limited, the tilt angle control of the hydraulic pump according to the flow rate of the hydraulic oil flowing into the turning motor is performed, so that the fuel consumption efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic shovel according to an embodiment of the present invention.

FIG. 2 is a side view of the excavator.

FIG. 3 is a dimensional diagram showing a relationship between a working radius and lengths and angles of components of the excavator.

FIG. 4 is a characteristic diagram showing a relationship (a) between a boom working radius l _{1 and} a boom angle α and a relationship (b) between an arm working radius l ₂ and an arm angle β.

FIG. 5 is a flowchart of control of the maximum tilt angle of the hydraulic pump and the tilt angle of the swing motor.

[6] the turning torque T for the work radius L (a), the tilting angle q _m of the turning motor for turning the torque T (b), the tilting angle q _m of the turning motor for the work radius L (c), the turning motor The maximum tilt angle q _p (d) of the hydraulic pump 1 with respect to the tilt angle q _m and the turning speed r _{pm with} respect to the working radius L
Characteristic diagram showing the relationship (e)

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Directional switching valve 5 Swing motor 6 Proportional control limiting cylinder 7,9 Proportional solenoid valve 8 Proportional control cylinder 10,11,12 Maximum pressure regulating valve 14 Revolving body 16 Traveling body 19 Boom 21 Arm 23 Bucket 25 Boom angle sensor 26 Arm Angle Sensor 30 Controller 61 Tilt Control Piston 62 Maximum Tilt Limit Piston

Claims (2)

[Claims] 1. A revolving body drive hydraulic circuit device that guides and rotates a discharge motor of a hydraulic pump through a direction switching valve for switching the direction and flow rate of a hydraulic pump to rotate a revolving body, A pump and the slewing motor are of variable capacity, and a measuring means for measuring a working radius which is a distance between a tip of a working machine mounted on the revolving body and a slewing center; and a work measured by the measuring means. First control means for controlling the tilt angle of the turning motor in accordance with the radius, and for limiting the maximum value of the flow rate of the working oil flowing into the turning motor regulated by the control of the first control means. And a second control means for controlling a tilt angle of the hydraulic pump. 2. The apparatus according to claim 1, wherein the second control means limits a maximum value of a control amount of the tilt angle control means for controlling a tilt angle of the hydraulic pump according to a discharge pressure of the hydraulic pump. The hydraulic circuit device for driving a swing body according to claim 1.