Multi-motor driving coupling type hydraulic excavator and transformation method

Abstract

A multi-motor drive coupling type hydraulic excavator comprises a power subsystem, a control subsystem and a hydraulic subsystem. The power subsystem comprises a power cabinet, a frequency converter, a plurality of three-phase asynchronous motors and a power coupler; the outputs of the three-phase asynchronous motors are connected into the power coupler, and the output of the power coupler drives a hydraulic pump of the hydraulic subsystem; the control subsystem is connected with the hydraulic subsystem and the power subsystem, and a frequency conversion instruction is generated through operation input of the hydraulic subsystem and input into the frequency converter. The hydraulic subsystem comprises a hydraulic action unit and an operation unit in the internal combustion engine hydraulic excavator; power grid power is connected into the hydraulic excavator, and a motor drives a hydraulic pump to provide power; the use cost is saved, and zero pollution and zero emission can be realized; an operator can work by using an operation interface of the original hydraulic subsystem without changing the original operation mode and habit; the improved scheme is easy to implement, and production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric machine control, and in particular to a multi-motor driven coupled hydraulic excavator and a modification method thereof. Background Art

[0002] The power system is the core component of the hydraulic excavator, and its performance is directly related to the performance and use cost of the hydraulic excavator. Traditional hydraulic excavators all use diesel engines as the power source of the machine. Hydraulic excavators with diesel engines as the power source have the characteristics of mature technology and supporting resources, convenient machine transfer, and little impact from surrounding environmental factors. Large hydraulic excavators are usually used in large mining areas. Because the diesel engine has high power and high fuel consumption per unit time, special oil supply vehicles are required to distribute fuel. Fuel consumption and fuel transportation costs have invisibly increased the cost of using the machine.

[0003] The existing excavators used for loading coal in the coal storage yard are traditional excavators powered by diesel engines. During the loading operation, the excavators can crush the coal and quickly clear the blocked coal loading ports, making them the best choice for loading coal in the coal storage yard. However, due to the almost 24-hour non-stop loading operation, the diesel consumption is very alarming, with a daily consumption of about two barrels of diesel, totaling about 3,360 yuan. During the entire heating period, the fuel cost is about 600,000 yuan.

[0004] The large hydraulic excavators used in large mining areas are characterized by long working hours at the same location and infrequent transfers. At the same time, mining areas usually have convenient electricity resources. If the excavator is powered by electricity, the cost of using the machine per unit time will be greatly reduced, and the machine can completely achieve zero pollution and zero emissions, which is more in line with the current trend of energy conservation and emission reduction.

[0005] The electrically driven hydraulic excavator systems proposed in the prior art either have a complex system structure or require heavy motors or high-voltage motors. They are not perfect in practical applications and cannot effectively solve on-site problems. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, a multi-motor driven coupled hydraulic excavator and a modification method thereof are proposed, which have a simple system structure, are easy to modify and have low cost.

[0007] A multi-motor driven coupled hydraulic excavator, comprising a power subsystem, a control subsystem, and a hydraulic subsystem; characterized in that:

[0008] The power subsystem includes power cabinet, frequency converter, multiple three-phase asynchronous motors, and power coupler;

[0009] The outputs of multiple three-phase asynchronous motors are connected to the power coupler, and the output of the power coupler drives the hydraulic pump of the hydraulic subsystem;

[0010] The control subsystem is connected to the hydraulic subsystem and the power subsystem, and utilizes the operation input of the hydraulic subsystem to generate a frequency conversion instruction and input it into the frequency converter;

[0011] The hydraulic subsystem is the hydraulic action unit and operating unit in the internal combustion engine hydraulic excavator.

[0012] A method for modifying a multi-motor driven coupled hydraulic excavator, characterized in that:

[0013] 1) Remove the internal combustion engine part of the original internal combustion engine hydraulic excavator and sort out the equipment installation plane; retain the hydraulic action unit and operation unit;

[0014] 2) Install the power cabinet, frequency converter, three-phase asynchronous motor and power coupler in the power subsystem;

[0015] 3) Install the throttle signal acquisition module and speed command conversion module in the control subsystem;

[0016] 4) The power coupler is mechanically connected to the hydraulic pump of the original hydraulic subsystem, the throttle signal acquisition module is connected to the throttle pedal in the original hydraulic subsystem, and the speed command conversion module is communicatively connected to the frequency converter;

[0017] 5) Power on the entire machine to test the various operating functions of the original hydraulic subsystem.

[0018] The beneficial effects of the present invention are:

[0019] Compared with the existing technology, by modifying the original internal combustion engine hydraulic excavator, connecting the power grid to the hydraulic excavator, and using the electric motor to drive the hydraulic pump to provide power for the machine, it can greatly save the cost of using the machine and achieve zero pollution and zero emission. Operators can operate using the original hydraulic subsystem operation interface without changing the original operation mode and habits. The improvement plan is easy to implement and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Provide a block diagram of the system.

[0021] Figure 2 This is a multi-motor layout diagram.

[0022] Figure 3 This is the power shaft layout diagram.

[0023] In the figure: power cabinet 11, frequency converter (121, 122, 123), three-phase asynchronous motor (131, 132, 133), power coupler 14, power shaft 144, input pulley (141, 142, 143), coupling 145, speed command conversion module 31, throttle signal acquisition module 32, hydraulic subsystem 21. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, a multi-drive coupling hydraulic excavator control system includes a power subsystem, a control subsystem, and a hydraulic subsystem.

[0026] The power subsystem includes a power cabinet 11, a frequency converter (121, 122, 123), a three-phase asynchronous motor (131, 132, 133), and a power coupler 14.

[0027] The power cabinet is connected to the external 380V three-phase industrial power, which is equipped with a low-voltage control circuit for power-on control and relay protection of the 380V power supply.

[0028] The power cabinet outputs 380V three-phase AC power to supply the inverter.

[0029] The frequency converter uses the on-off function of power semiconductor devices to convert the industrial frequency power supply into electrical energy of another frequency. First, the alternating current is converted into direct current, and then the direct current is switched back into alternating current using electronic components. Generally, higher-power frequency converters use thyristors and are equipped with an adjustable frequency device to make the frequency adjustable within a certain range. This is used to control the speed of the motor so that the speed can be adjusted within a certain range.

[0030] The inverter output is connected to a three-phase asynchronous motor.

[0031] The three-phase asynchronous motor uses a 30Kw motor. In order to match the original hydraulic subsystem, a driving power of more than 85Kw is required. If a single motor of more than 85Kw is used, its size is too large and is not suitable for the existing installation space.

[0032] Three 30Kw motors can be used, and their total power meets the requirements.

[0033] like Figure 2 As shown, arrange the motor mounting bracket.

[0034] The mounting base has a three-layer design, with three 30Kw motors installed in a staggered arrangement on each layer. Its vertical projection area is small and can be applied to existing installation space.

[0035] An output pulley is installed at the output shaft of each motor, and the output power is driven by a belt.

[0036] like Figure 3 As shown, the power coupler 14 has a power shaft 144, which is a multi-stage stepped shaft with three input pulleys (141, 142, 143) mounted thereon. The three input pulleys and the output pulleys of the three motors use transmission belts for power transmission.

[0037] A coupling 145 is also mounted on the power shaft, and the coupling 145 is connected to the hydraulic pump in the original hydraulic subsystem.

[0038] Through the power shaft, the power of three 30Kw motors is coupled to meet the power requirements of the hydraulic system.

[0039] The control subsystem includes a throttle signal acquisition module 32 and a rotation speed command conversion module 31 .

[0040] The throttle signal acquisition module 32 is arranged at the operator's position.

[0041] The throttle signal acquisition module 32 is connected to the original hydraulic subsystem, and can acquire the position status of the throttle pedal in the original hydraulic subsystem.

[0042] The collected signal is input into the speed command conversion module 31, and the speed command conversion module 31 calculates the required frequency conversion command, and the frequency conversion command is synchronously transmitted to the frequency converter (121, 122, 123) to adjust and control the speed of the three asynchronous motors (131, 132, 133). By using the control subsystem, the operator does not need to change the original operation mode and habit, and can use the original hydraulic subsystem operation interface to operate.

[0043] Example:

[0044] The current production situation of the coal yard of the fuel department is that from November to March of the following year, due to the cold weather, the coal loading port is seriously blocked, affecting safe production. In order to ensure smooth coal loading and stable operation of the unit, an excavator is used to load coal from November to March of the following year. The annual use cost of the excavator is about 150 days × 1,600 yuan = 240,000 yuan, and the fuel cost is two barrels of 35-grade diesel per day (24 hours), 420 liters × 8.5 yuan × 150 days = 535,500 yuan, with a total amount of 775,500 yuan (excluding frozen train coal). Since the coal loading excavator does not leave the coal loading port and does not need to walk during the 196-day production period, an old excavator is modified and the engine is replaced with an electric motor, which is very in line with the coal loading needs of the plant. The 380V power supply is taken from the crane slide line as the power source of the excavator. No fuel is required for coal loading during the entire heating period, saving costs every year, and it has long-term economical considerations.

[0045] At present, the market price of old excavator 220 is about 60,000-80,000 yuan. Modification plan and modification cost budget: three 30kw-2 electric motors, three 45kw inverters, 9-groove pulleys with a diameter of 240 mm; three sets of 3-groove pulleys with a diameter of 200 mm; one set of electrical cabinet assembly; one set of electronic control system. The modification fee + excavator cost totals 260,000-280,000 yuan.

[0046] During the implementation of specific equipment transformation,

[0047] 1) Remove the internal combustion engine part of the original excavator. Arrange the equipment installation plane. Keep the hydraulic action unit and operation unit;

[0048] 2) Install the power cabinet, inverter, three-phase asynchronous motor and power coupler in the power subsystem.

[0049] Connect to three-phase power supply and debug electrical performance and power coupling performance.

[0050] 3) Install the throttle signal acquisition module and speed command conversion module in the control subsystem, and debug the signal acquisition and frequency conversion command output.

[0051] 4) The power coupler is mechanically connected to the hydraulic pump of the original hydraulic system, the throttle signal acquisition module is connected to the throttle pedal in the original hydraulic subsystem, and the speed command conversion module is communicatively connected to the frequency converter.

[0052] 5) Power on the entire machine to test the various operating functions of the original hydraulic system.

[0053] After completing the installation and debugging of each unit of the equipment, the excavator can be used normally for operation. By connecting the power grid to the hydraulic excavator, the electric motor drives the hydraulic pump to provide power for the machine; it can greatly save the cost of using the machine and achieve zero pollution and zero emission. Operators can operate using the original hydraulic subsystem operation interface without changing the original operation mode and habits. The improvement plan is easy to implement and improves production efficiency.

[0054] Finally, it should be noted that the above description is only an explanation of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-motor driven coupled hydraulic excavator, comprising a power subsystem, a control subsystem, and a hydraulic subsystem; characterized in that: The power subsystem includes power cabinet, frequency converter, multiple three-phase asynchronous motors, and power coupler; The outputs of multiple three-phase asynchronous motors are connected to the power coupler, and the output of the power coupler drives the hydraulic pump of the hydraulic subsystem; The control subsystem is connected to the hydraulic subsystem and the power subsystem, and utilizes the operation input of the hydraulic subsystem to generate a frequency conversion instruction and input it into the frequency converter; The hydraulic subsystem is the hydraulic action unit and operating unit in the internal combustion engine hydraulic excavator.

2. A multi-motor driven coupling type hydraulic excavator according to claim 1, characterized in that: Three three-phase asynchronous motors are used, and the mounting base has a three-layer design, and the three motors are staggered and installed on each layer.

3. A multi-motor driven coupling type hydraulic excavator according to claim 2, characterized in that: The power coupler has a power shaft which adopts a multi-section stepped shaft and is provided with three input pulleys.

4. A multi-motor driven coupling type hydraulic excavator according to claim 3, characterized in that: The three input pulleys and the output pulleys of the three motors use transmission belts for power transmission.

5. The multi-motor driven coupling type hydraulic excavator according to claim 2, characterized in that: A coupling is also mounted on the power shaft, and the coupling is connected to a hydraulic pump in the hydraulic subsystem.

6. The multi-motor driven coupling type hydraulic excavator according to claim 1, characterized in that: The control subsystem includes a throttle signal acquisition module and a speed command conversion module; The throttle signal acquisition module is connected to the hydraulic subsystem and can collect the position status of the throttle pedal in the hydraulic subsystem; The collected signal is input into the speed command conversion module, which calculates the required frequency conversion command. The frequency conversion command is synchronously transmitted to the three frequency converters to adjust and control the speed of the three motors.

7. The multi-motor driven coupling type hydraulic excavator according to claim 1, characterized in that: The three-phase asynchronous motor uses a 30Kw motor.

8. The multi-motor driven coupling type hydraulic excavator according to claim 1, characterized in that: The power cabinet is connected to external 380V three-phase industrial power.

9. A method for modifying a multi-motor driven coupled hydraulic excavator as claimed in claim 1, characterized in that: 1) Remove the internal combustion engine part of the original internal combustion engine hydraulic excavator and sort out the equipment installation plane; retain the hydraulic action unit and operation unit; 2) Install the power cabinet, frequency converter, three-phase asynchronous motor and power coupler in the power subsystem; 3) Install the throttle signal acquisition module and speed command conversion module in the control subsystem; 4) The power coupler is mechanically connected to the hydraulic pump of the original hydraulic subsystem, the throttle signal acquisition module is connected to the throttle pedal in the original hydraulic subsystem, and the speed command conversion module is communicatively connected to the frequency converter; 5) Power on the entire machine to test the various operating functions of the original hydraulic subsystem.

10. The transformation method according to claim 9, characterized in that: In step 2), three-phase power supply is connected to debug electrical performance and power coupling performance; In step 3), debug signal acquisition and frequency conversion instruction output.

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