CN103382951B - The swivel gear of Work machine and this Work machine - Google Patents

Abstract

To provide a work machine that can arbitrarily adjust the output of the hydraulic motor by controlling the pressure of the pressure oil supplied to the hydraulic motor to reduce energy consumption by suppressing the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor Slewing device and the working machine. The slewing device mounted on a work machine with a slewing function includes: a hydraulic motor that outputs slewing torque; a variable capacity hydraulic pump that supplies pressure oil to the hydraulic motor and can adjust the capacity through a control device; a control device that can be adjusted The capacity of the variable capacity hydraulic pump; the pressure detection device detects the pressure of the hydraulic pump and inputs it to the control device; during the rotary drive, the control device adjusts the capacity of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes the specified The target pressure controls the pressure oil supplied to the hydraulic motor, thereby suppressing the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor.

Description

Rotary device of working machine and the working machine

technical field

The present invention relates to a turning device in working machines such as construction machinery and agricultural machinery, and the working machine, and more particularly to a turning device in working machines that minimize energy consumption during turning operation and actively control turning torque, and the working machine .

Background technique

A construction machine such as a hydraulic excavator generally includes a hydraulic cylinder that drives a boom, an arm, a bucket, and the like, and a hydraulic motor that drives a turntable, a traveling crawler, or a vehicle. To these hydraulic actuators, required pressure oil is supplied from a hydraulic pump via respective hydraulic control valves of a control valve unit mounted on the turntable.

For example, in Patent Document 1, it is described that "In order to provide a hydraulic excavator capable of reducing energy waste caused by the excess flow in the relief valve in the hydraulic motor unit as much as possible, the hydraulic motor HM in the swing motor unit 10 is arranged And a pair of relief valve RF and check valve CK. Opposite to the output shaft X of the swing motor HM, a rotation speed detector 11 is provided to provide an electrical signal S1 corresponding to the rotation speed of the swing motor to the calculation unit 14 . An electrical signal S2 is also given to the calculation unit. This signal is the output of the oil/electric converter 17 that detects the discharge side pressure P of the rotary pump 4. The output of the calculation unit is the flow command value Q to the electromagnetic proportional valve 16 and the output to the electromagnetic proportional valve 16. There are two kinds of command absorption torque value Tm of the electromagnetic proportional valve 19. The rotary pump is specially configured for the rotary motor, and the rotary pump control part 5 is controlled by the above-mentioned calculation part to meet the actual flow rate of the rotary motor and the need of the relief valve RF The flow Q of the sum of the minimum flows.".

Patent Document 1 describes a method of controlling a hydraulic pump by detecting the speed of the swing motor and feeding it back to the hydraulic pump in order to suppress the excess of the flow rate supplied from the hydraulic pump to the hydraulic motor that has conventionally been discharged through the relief valve. Able to supply the required minimum flow.

Patent Document 1: JP-A-2011-208790.

However, in Patent Document 1, since the speed of the swing motor is detected and controlled in order to control the remaining amount of the flow rate, there is no mention of the control of the passing pressure as another method of controlling the hydraulic pump. The output torque of the hydraulic motor is proportional to the capacity and pressure of the hydraulic motor. Therefore, when the hydraulic motor has a fixed capacity, the output torque is determined by the pressure. That is, the pressure of the hydraulic motor has a large influence on the turning ability such as turning force and turning time. However, in Patent Document 1, the control method exclusively detects the speed of the swing motor, and does not aim at control by pressure, so the output torque cannot be positively controlled.

Contents of the invention

Therefore, it is an object of the present invention to solve the above-mentioned problems, and to provide a hydraulic pump capable of reducing energy consumption by suppressing the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor, and by controlling the flow rate to the hydraulic motor. The rotary device of the working machine and the working machine that arbitrarily adjust the output of the hydraulic motor by the pressure of the supplied pressure oil.

In order to solve the above-mentioned problems, the turning device of the working machine according to the present invention is a turning device mounted on a working machine having a turning function, and includes: a hydraulic motor outputting turning torque; and a variable capacity hydraulic pump supplying torque to the hydraulic motor. The pressure oil can adjust the capacity through the control device; the control device can adjust the capacity of the above-mentioned variable capacity hydraulic pump; the pressure detection device can detect the pressure of the hydraulic pump and input it to the control device; The capacity controls the pressure oil supplied to the hydraulic motor so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, thereby suppressing the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor.

In addition, it is characterized in that, in order to adjust the displacement of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, when the pressure of the hydraulic pump is higher than the above-mentioned target pressure, the control device is characterized in that , the capacity of the hydraulic pump is decreased, and when the pressure of the hydraulic pump is lower than the above-mentioned target pressure, the capacity of the hydraulic pump is increased.

Furthermore, it is characterized in that the target pressure is changed according to the output torque.

Next, it is characterized in that the hydraulic pump is driven by an engine.

On the other hand, the above-mentioned hydraulic pump is driven by an electric motor, and the control device adjusts the rotation of the electric motor; when the rotation is driven, the control device adjusts the rotation of the electric motor so that the pressure of the hydraulic pump input from the pressure detection device becomes a specified value. The target pressure controls the pressure oil supplied to the hydraulic motor, thereby suppressing the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor.

In addition, as another invention for solving the above-mentioned problems, a work machine is a work machine equipped with a swing function, and includes: a hydraulic motor that outputs a swing torque; a variable displacement hydraulic pump that supplies pressure oil to the hydraulic motor, and can be controlled The device adjusts the capacity; the control device adjusts the capacity of the above-mentioned variable capacity hydraulic pump; the pressure detection device detects the pressure of the hydraulic pump and inputs it to the control device; during the rotary drive, the control device adjusts the capacity of the hydraulic pump to make the pressure detection The pressure of the hydraulic pump input to the device becomes a predetermined target pressure, and the pressure oil supplied to the hydraulic motor is controlled to suppress the discharge flow rate of the hydraulic pump to the minimum flow rate required by the hydraulic motor.

According to the swing device of the present invention, since the hydraulic pump discharges only the minimum flow rate required to achieve the target pressure according to the rotational speed of the hydraulic motor, it is possible to provide a swing device with very high energy efficiency. In addition, a working machine equipped with the turning device can reduce fuel consumption. In addition, the work efficiency of the work machine can be improved by using the amount of energy reduced by the turning device in other actuators. Furthermore, since the target pressure is provided as a parameter of the control device, the output torque of the hydraulic motor can be adjusted by changing the parameter according to the situation, so the torque corresponding to the request of the operator of the working machine can be output, and the operability of the working machine can be improved. improve.

Description of drawings

FIG. 1 is a first embodiment of a swing device according to the present invention, and is a hydraulic circuit diagram of a hydraulic excavator including a dedicated swing pump and a hydraulic motor for rotationally driving an upper swing body.

Fig. 2 is a first embodiment of the turning device according to the present invention, and is a block diagram of a control device.

Fig. 3 is a flow chart illustrating the operation of the first embodiment of the turning device according to the present invention.

Fig. 4 is a second embodiment of the slewing device according to the present invention, and is a hydraulic circuit diagram of a hydraulic excavator including a dedicated slewing pump and a hydraulic motor for rotationally driving an upper slewing body.

Fig. 5 is a second embodiment of the turning device according to the present invention, and is a block diagram of a control device.

FIG. 6 shows the characteristics of the hydraulic excavator to which the control method of the present invention is applied—at the time of acceleration.

detailed description

Embodiments of the present invention will be described using FIGS. 1 to 6 .

[Example 1]

First, a first embodiment of the present invention will be described using FIGS. 1 to 3 and 6 .

FIG. 1 is a hydraulic circuit diagram of a hydraulic excavator including a dedicated swing pump and a hydraulic motor for rotationally driving an upper swing body. In Fig. 1, reference numeral 2 is an engine (prime mover) that consumes fossil fuels such as gasoline and generates rotational driving force on an output shaft Y, and a variable capacity type rotary pump (hydraulic pump) is arranged on this shaft Y 4.

An oil/electric converter 24 is provided at the output of the rotary pump 4 , and transmits a pressure signal P to the control device 16 via a wiring 22 . The above-mentioned rotary pump 4 is provided with a rotary pump control unit 6 for controlling the flow rate.

Reference numeral 6 is a rotary pump control unit, and a hydraulic pressure control signal is applied from the electromagnetic proportional valve 28 for flow control via a pressure oil signal line.

Reference numeral 8 denotes a switching control valve for turning, to which operating pressure signals SG1 and SG2 from the pilot valve 14 are applied. A pressure oil source is supplied to the pilot valve 14 from a gear pump not shown. In addition, the above-mentioned switching control valve 8 for turning constitutes the first switching control valve of the present invention.

Reference numeral 10 denotes a swing motor unit, and a swing motor 12 for swing capable of normal and reverse rotation, a pair of relief valves 30 and 31 and check valves 32 and 33 are arranged in this unit. An unillustrated upper turntable is rotatably coupled to the output shaft X of the swing motor 12 via an unillustrated speed reducer and an unillustrated pinion.

The above-mentioned pilot valve 14 is provided with an angle sensor 20 for measuring the inclination angle of the operating lever of the pilot valve 14 . The angle sensor is formed by, for example, a rotary encoder. The measured angle information is output to the control device 16 via a line 18 as a signal Ang.

The control device 16 receives an angle signal Ang from the pilot valve 14 and a pressure signal P from the oil/electric converter 24 , and has an output signal Q for driving the electromagnetic proportional valve 28 for flow control. More specifically, the control device 16 includes an AD converter 40 for converting the signal Ang and the signal P from an analog signal to a digital signal, a RAM 42 as a memory for storing target pressure and measured data, and a program based on the signal Ang and the signal P. P calculates the central processing unit (CPU) 44 for driving the signal Q of the electromagnetic proportional valve 28 for flow control, the ROM 46 stores the program for operating the CPU 44, and uses the signal Q as the calculated digital value for flow control. The DA converter 48 for converting the analog signal to the electromagnetic proportional valve 28 .

Next, the operation of the hydraulic excavator as the working machine according to the present invention having the above-mentioned structure will be described below.

As shown in FIG. 3 , first, the target pressure is set as Pt, which is output to the control device 16 from an interface not shown in the figure, and stored in the RAM 42 by the CPU 44 ( S2 ).

The rotary pump 4 is driven by the engine 2 . When the operator of the hydraulic excavator does not operate the operation lever of the pilot valve 14 and does not make any input, that is, the control device 16 detects the rotation angle Ang of the angle sensor 20 ( S4 ).

If the rotation angle is 0 degrees, the central processing unit (CPU) 44 outputs a signal to the pump control unit 6 according to the program so that the capacity of the rotary pump 4 becomes near zero ( S6 ).

Furthermore, when the operator of the hydraulic excavator operates the operating lever of the pilot valve 14, the switching valve 8 is switched according to the operating direction of the operating lever. The oil passage connecting the rotary pump 4 and the rotary motor 12 is opened. If the rotation angle Ang of the angle sensor 20 is not 0 degrees, the central processing unit (CPU) 44 of the control device 16 measures the pressure P detected by the oil/electric converter 24 ( S8 ). The CPU 44 stores the measured pressure P in the RAM 42 .

The CPU 44 performs pressure oil determination ( S10 ).

If the pressure P of the pressurized oil is P>Pt, the CPU 44 sets a signal to the pump control unit 6 to reduce the pump capacity ( S12 ).

On the other hand, if the pressure P of the pressurized oil is P=Pt, the signal to the pump control unit 6 is set so as not to change the pump capacity ( S14 ).

Furthermore, if the pressure P of the pressurized oil is P<Pt, a signal to the pump control unit 6 is set to increase the pump capacity ( S16 ).

The above is repeated until the value of P becomes the target value.

As a result, the swing motor 12 is supplied with pressure oil from the swing pump 4 to output a swing torque. The hydraulic excavator, which is a working machine, performs a swing operation by the swing torque. The discharge flow rate of the rotary pump 4 is approximately proportional to the rotation of the rotary motor 12, and the rotary motor 12 discharges only the minimum flow rate required for the rotation while maintaining the target pressure Pt.

At this time, since the relief valves 30 and 31 of the swing motor 12 are set to operate at a pressure higher than the target pressure Pt, they do not operate.

6 shows graphs of the pump pressure (MPa), the pump discharge flow rate (L/min) of the rotary pump 4 , and the rotary motor rotation speed (rpm) of the rotary pump 4 in Example 1 with respect to the start-up time.

First, the pump pressure (MPa) of the rotary pump 4 becomes substantially constant after 0.5 sec. On the other hand, it can be seen that the pump discharge flow rate (L/min) of this pump increases approximately in proportion to time.

When the rotary speed increases and the rotary pump 4 reaches the maximum capacity, the rotary speed becomes a steady speed, and the discharge pressure of the rotary pump 4 becomes a pressure corresponding to the inertial force of the rotary pump 4 .

On the other hand, when there is a possibility that the output of the rotary pump 4 exceeds the maximum output of the engine 2 , the output control of the rotary pump 4 is performed by the control device 16 . Since the output of the rotary pump 4 is the product of the discharge flow and the pressure of the rotary pump 4, if the discharge flow increases due to the increase in the rotary speed and the output of the rotary pump 4 becomes near the maximum output of the engine 2, the control device 16 sets the target The pressure Pt is lowered, and control is performed so that the output of the rotary pump 4 does not exceed the maximum output of the engine 2 while ensuring the discharge flow rate of the rotary pump 4 .

When the input of the operation lever of the pilot valve 14 is released and the turning deceleration state is established, the switching valve 8 returns to the neutral position, and the oil passage between the turning pump 4 and the turning motor 12 is blocked. The capacity of the rotary pump 4 is controlled near zero. The swing motor 12 is rotated by the inertial force of the swing, but since it is a closed circuit, the relief valves 30 and 31 operate to act as a braking force to decelerate the swing.

Since the rotary motor is a fixed-quantity pump, its target pressure is set to match the required output torque. The output torque is proportional to the target pressure.

[Example 2]

Next, Example 2 will be described using FIGS. 4 to 6 . Compared with Example 1, it demonstrates centering on a different point.

FIG. 4 is a hydraulic circuit diagram of a hydraulic excavator including a dedicated swing pump driven by an electric motor 52 and a hydraulic motor for swing. In FIG. 4 , reference numeral 52 is an electric motor that is connected to a battery or the like as a power source and generates rotational driving force on an output shaft Y, and a fixed-capacity rotary pump 54 is disposed on the shaft Y.

The control device 66 of the present invention is similar to the first embodiment in that the angle signal Ang from the pilot valve 64 and the pressure signal P from the oil/electric converter 74 are input, but it is directly connected to the electric motor 52. It is different from Example 1 in one point.

In addition, the control apparatus 66 has the structure similar to Example 1 in the point which has the AD converter 90, RAM92, the central processing unit (CPU) 94, and ROM96. However, in the control device 66 of the second embodiment, a PWM power supply circuit 98 is provided instead of a DA converter.

Here, regarding the operation of the second embodiment, points different from those of the first embodiment will be described. The difference from Embodiment 1 is that the discharge flow rate of the fixed displacement pump is controlled by the rotation speed of the electric motor.

In the flowchart of FIG. 3, it is the same flow up to S4. Then, based on the pressure signal P and the target pressure Pt, PID processing is performed by a PID processing program loaded in the ROM. Output the result after PID processing with the duty ratio signal λ. The output duty ratio signal λ is input to the PWM power supply circuit 98, and a signal to the electric motor rotation control unit is output as a signal for controlling the rotation of the electric motor.

The rotational speed of the rotary motor of the present invention increases linearly as described in FIG. 6 .

As mentioned above, although the preferred embodiment of this invention was demonstrated using drawing, it is needless to say that those skilled in the art can make various deformation|transformation based on said drawing and description.

Explanation of reference signs

2 engines

4 rotary pump (hydraulic pump)

6 rotary pump control unit

8 switch control valve

10-turn motor unit

12 rotary motor

14 pilot valve

16 control device

18 lines

20 angle sensor

22 Wiring

24 oil/electric converter

28 Electromagnetic proportional valve for flow control

30, 31 overflow valve

32, 33 check valve

40AD converter

42RAM

44 Central Computing Unit (CPU)

46ROM

48DA converter

52 electric motor

54 rotary pump

64 pilot valve

66 control device

74 oil/electric converter

90AD Converter

92RAM

94 Central Computing Unit (CPU)

96ROM

98PWM power supply circuit

Ang signal

SG1, SG2 operating pressure signal

P pressure signal

Q signal.

Claims (5)

1. A rotary device of an operating machine, which is a rotary device mounted on an operating machine having a rotary function, characterized in that, have: Hydraulic motor, output rotary torque; Variable capacity hydraulic pump, which supplies pressure oil to the hydraulic motor above, and can adjust the capacity through the control device; a control device for adjusting the capacity of the above-mentioned variable capacity hydraulic pump; The pressure detection device detects the pressure of the hydraulic pump and inputs it to the control device; During slewing drive, the control device adjusts the capacity of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, and controls the pressure oil supplied to the hydraulic motor, thereby controlling the discharge flow rate of the hydraulic pump. I suppress the minimum flow rate necessary for a hydraulic motor, During slewing drive, in order to adjust the capacity of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, the control device adjusts the capacity of the hydraulic pump when the pressure of the hydraulic pump is higher than the above-mentioned target pressure. Decrease to increase the capacity of the hydraulic pump when the pressure of the hydraulic pump is lower than the above-mentioned target pressure. 2. The turning device of a working machine according to claim 1, wherein: The target pressure changes according to the output torque. 3. The turning device of a working machine according to claim 1, wherein: The above-mentioned hydraulic pump is driven by the engine. 4. The turning device of a working machine according to claim 1, wherein: The hydraulic pump is driven by an electric motor, and the control device adjusts the rotation of the electric motor; During the turning drive, the control device controls the pressure oil supplied to the hydraulic motor by adjusting the rotation of the electric motor so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, thereby controlling the discharge flow rate of the hydraulic pump. Suppresses the minimum flow required for hydraulic motors. 5. A work machine, which is a work machine equipped with a turning function, characterized in that: have: Hydraulic motor, output rotary torque; Variable capacity hydraulic pump, which supplies pressure oil to the hydraulic motor above, and can adjust the capacity through the control device; a control device for adjusting the capacity of the above-mentioned variable capacity hydraulic pump; The pressure detection device detects the pressure of the hydraulic pump and inputs it to the control device; During slewing drive, the control device adjusts the capacity of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, and controls the pressure oil supplied to the hydraulic motor, thereby controlling the discharge flow rate of the hydraulic pump. I suppress the minimum flow rate necessary for a hydraulic motor, During slewing drive, in order to adjust the capacity of the hydraulic pump so that the pressure of the hydraulic pump input from the pressure detection device becomes a predetermined target pressure, the control device adjusts the capacity of the hydraulic pump when the pressure of the hydraulic pump is higher than the above-mentioned target pressure. Decrease to increase the capacity of the hydraulic pump when the pressure of the hydraulic pump is lower than the above-mentioned target pressure.