CN106013312A - Fully-electrically-driven hydraulic excavator power system - Google Patents

Abstract

The present invention relates to an all-electrically driven hydraulic excavator power system, which includes a hydraulic actuator, a bidirectional quantitative pump, a servo motor, a frequency converter, a controller, and a clutch controller. The clutch controller receives power from a plug-in mode or a battery mode. The controller receives the signal input by the driver to control the speed of each hydraulic actuator through the handle, and calculates the control signal of each hydraulic actuator, and then transmits it to the frequency converter. The battery mode takes power and converts it into the voltage of each servo motor connected to it to control the speed and direction of each servo motor, so as to control the size and direction of the output flow of the bidirectional quantitative pump connected to it, and finally complete the control of each hydraulic pressure. Speed control of actuators. The present invention eliminates the internal combustion engine widely used at present, continues the high power advantage of the hydraulic system, and adopts a volume control mode to achieve effective integration of energy saving and emission reduction.

Description

All-electric hydraulic excavator power system

technical field

The invention relates to an excavator power system, in particular to a power system of an all-electrically driven hydraulic excavator.

Background technique

In recent years, under the background of energy shortage and increasing environmental pollution, research on energy saving and emission reduction of hydraulic systems, which generally have the disadvantages of low efficiency and poor emissions, has become a hot spot. Although the existing energy-saving methods for hydraulic systems have played an important role in improving efficiency, they still have obvious shortcomings. For example, the use of internal combustion engines as the main power None of the emission reduction methods can fundamentally solve the problem of "zero pollution". At the same time, with the diversity of power generation methods and high efficiency of power generation, as well as the zero-pollution advantages of the power system, if the electric technology is integrated into the excavator system, the pollution problem will be fundamentally solved. However, due to the special working conditions of the excavator, hydraulic components with high power density are required to be driven, so the present invention combines the advantages of the electric system and the hydraulic system, and proposes an all-electric drive hydraulic excavator power system, thereby eliminating the need for The internal combustion engine is widely used now, and it continues the high power advantage of the hydraulic system, and adopts the volume control method, which theoretically eliminates the throttling loss and achieves the effective fusion of energy saving and emission reduction.

Contents of the invention

The present invention aims to provide an all-electrically driven hydraulic excavator power system, which eliminates the widely used internal combustion engine, continues the high power advantage of the hydraulic system, and adopts a volume control method to achieve an effective fusion of energy saving and emission reduction.

In order to achieve the above object, the technical solution of the present invention is: an all-electrically driven hydraulic excavator power system, including a hydraulic actuator, a bidirectional quantitative pump, a servo motor, a frequency converter, a controller, and a clutch controller, characterized in that: The clutch controller receives the power supply signal in plug-in mode or battery mode, the controller receives the signal input by the driver through the handle to control the speed of each hydraulic actuator, and calculates the control signal of each hydraulic actuator, and then transmits it to the frequency conversion The frequency converter takes power from plug-in mode or battery mode through the clutch controller, and converts it into the voltage of each servo motor connected to it to control the speed and direction of each servo motor, so as to control the bidirectional quantitative pump connected to it. The size and direction of the output flow, and finally complete the speed control of each hydraulic actuator.

The hydraulic actuators include travel motors, stick cylinders, and bucket cylinders. The travel motors and stick cylinders, or the travel motors and bucket cylinders are connected to the same set of bidirectional quantitative pumps and servo motors through switching valve groups. The group performs switching control between the travel motor and the arm cylinder, or between the travel motor and the bucket cylinder.

A plurality of the servo motors are connected together through the shaft, or are respectively arranged near each hydraulic actuator.

The control signal input by the controller to the frequency converter is a control voltage, and the frequency converter respectively controls the speed and direction of the servo motors in each module to realize the control of the hydraulic actuators.

The stick cylinder and the bucket cylinder are symmetrical hydraulic cylinders with a single rod, so as to realize the flow balance between the two chambers of the hydraulic cylinder.

The beneficial effects of the present invention are:

1. Using electric energy as the main energy source of the power system eliminates the traditional internal combustion engine and achieves the goal of "zero emission and zero pollution".

2. In the invention, the clutch controller is set to switch the source of electric energy as direct plug-in or short-term power supply by the battery carried by the excavator. Thereby expanding the scope of application.

3. Each hydraulic actuator is made into a modular structure, so that each actuator can be operated independently without affecting each other. Due to the removal of the engine, the layout of the whole machine is more flexible. Multiple servo motors can be connected together through the shaft, or they can be arranged near each actuator.

4. The control quantity is the control voltage input to the frequency converter, and the frequency converter controls the speed and direction of the motors of each module respectively to realize the control of the actuators. The advantage of the high power density of the hydraulic system is thereby preserved.

5. The single-rod symmetrical hydraulic cylinder is used to replace the single-rod asymmetric hydraulic cylinder, which solves the problem of unbalanced flow in the two chambers. The traditional method uses a pair of hydraulic control check valves in parallel to solve the problem of unbalanced flow. However, due to the slow response of the hydraulic control check valves, the control effect is not good. In the present invention, a symmetrical hydraulic cylinder is proposed to make up for this problem. The disadvantage is that it can greatly reduce the number of openings of the hydraulically controlled one-way valve used for oil replenishment in the schematic diagram. Makes the control more convenient and accurate.

Description of drawings

Fig. 1 is a power system diagram of an all-electrically driven hydraulic excavator of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, an all-electric drive hydraulic excavator power system includes hydraulic actuators, bidirectional quantitative pump 2, servo motor 1, low-voltage accumulator 4, frequency converter, controller, and clutch controller.

The hydraulic actuators include the first and second switching valve groups 7, 8, hydraulic check valve 3, the first and second travel motors 9, 10, stick symmetrical cylinder 11, bucket symmetrical cylinder 12, boom symmetrical cylinder 6, Swing motor 5 etc.

The clutch controller receives the power supply signal in plug-in mode or battery mode. The controller receives the signal input by the driver through the handle to control the speed of each hydraulic actuator, and calculates the control signal of each hydraulic actuator, and then transmits it to the frequency converter. The frequency converter takes power from plug-in mode or battery mode through the clutch controller, and converts it into the voltage of each servo motor connected to it to control the speed and direction of each servo motor, thereby controlling the output of the bidirectional quantitative pump connected to it The size and direction of the flow, and finally complete the speed control of each hydraulic actuator. A plurality of the servo motors are connected together through the shaft, or are respectively arranged near each hydraulic actuator.

The control signal input by the controller to the frequency converter is the control voltage, and the frequency converter controls the speed and direction of the servo motors in each module respectively to realize the control of the hydraulic actuators.

A plurality of servo motors are connected together through the shaft, or are respectively arranged near each hydraulic actuator.

The basic working process of the present invention is that the driver first selects the plug-in mode or the battery mode according to the actual situation (wherein the plug-in mode refers to direct supply through the power line, and the battery mode refers to charging the battery through the power line and then powered by the battery), and The clutch control signal determines the power supply mode; then the driver inputs the signal to control the speed of each actuator through the handle, the controller calculates the control signal of each actuator, and then transmits it to the inverter, and the inverter switches from plug-in or battery mode through the clutch controller Take electricity and convert it into the voltage of each servo motor connected to it to control the speed and direction of each servo motor, so as to control the size and direction of the output flow of the quantitative pump connected to it, and finally complete the control of each hydraulic actuator speed control.

Considering that the travel motor, arm and bucket do not move at the same time, in order to save costs, the same switching valve group as the Chinese patent CN201310322449.5 is used for switching control, that is, the same set of servo motors combined with quantitative pumps is used to control the first travel. The motor 9 and the stick symmetrical cylinder 11 (or the second travel motor 10 and the bucket symmetrical cylinder 12) are switched and controlled.

Claims (5)

1. a complete electrically driven (operated) hydraulic crawler excavator dynamical system, including hydraulic actuator, two-way quantitative pump, servomotor, converter, controller, clutch controller, it is characterized in that: described clutch controller receives plug-in pattern or battery mode power supply signal, described controller receives the signal controlling each hydraulic actuator speed that driver is inputted by handle, and calculate the control signal of each hydraulic actuator, it is transferred to converter again, converter passes through clutch controller from plug-in pattern or battery mode power taking, change into the voltage of each servomotor connected, control rotating speed size and the rotary speed direction of each servomotor, thus control the size and Orientation of the output flow of connected two-way quantitative pump, it is finally completed the speed controlling to each hydraulic actuator.

Complete electrically driven (operated) hydraulic crawler excavator dynamical system the most according to claim 1, it is characterized in that: described hydraulic actuator includes running motor, bucket arm cylinder, bucket cylinder, described running motor and bucket arm cylinder or running motor and bucket cylinder connect same set of two-way quantitative pump and servomotor by switching valve group, carry out the switching control between running motor and bucket arm cylinder or between running motor and bucket cylinder by switching valve group.

Complete electrically driven (operated) hydraulic crawler excavator dynamical system the most according to claim 1, it is characterised in that: multiple described servomotor axises connect together, or are arranged near each hydraulic actuator.

Complete electrically driven (operated) hydraulic crawler excavator dynamical system the most according to claim 1, it is characterized in that: described controller inputs to the control signal of converter for controlling voltage, converter controls rotating speed and the direction of the servomotor in modules respectively, realizes the control to hydraulic actuator.

Complete electrically driven (operated) hydraulic crawler excavator dynamical system the most according to claim 2, it is characterised in that: described bucket arm cylinder and bucket cylinder are single rod symmetrical hydraulic cylinder, it is achieved the balance of hydraulic cylinder two chamber flow.