Flow control method and system for hydraulic accessory of electric excavator and electric excavator

Abstract

The invention provides a flow control method and system for a hydraulic accessory of an electric excavator and the electric excavator, and relates to the technical field of engineering machinery. The method comprises the following steps: acquiring input gear information and a maximum flow value; according to the motor rotating speed corresponding to the gear information and the maximum flow value, the maximum value of the required displacement is determined; oil supply modes of main pumps of the hydraulic system are determined according to the maximum value of the required displacement, the oil supply modes of the main pumps comprise a single-pump oil supply mode and a double-pump oil supply mode, and the main pumps comprise a front pump and a rear pump; according to the voltage of the handle dial wheel and the maximum value of the required displacement, the current required displacement is determined; and according to the oil supply mode of the main pump and the current required displacement, the output currents of the front pump and the rear pump are determined, and the opening degree of the corresponding reversing valve is controlled according to the output currents of the front pump and the rear pump. According to the method, the flow adjusting range can be widened, the flow can be accurately and gently controlled, and controllability is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery, and in particular to a flow control method and system for hydraulic accessories of an electric excavator, and an electric excavator. Background Art

[0002] Electric excavators use the hydraulic oil in the hydraulic system to power their accessories. The flow of the hydraulic oil determines the speed of the hydraulic actuator. It is very important to control the flow of the hydraulic oil accurately and smoothly.

[0003] In the related technology, positive flow control with higher flow control accuracy is gradually becoming popular in electric excavators. During the positive flow control process, the pressures output by the main pump and the pilot operating handle are in direct proportion. The controller can determine the flow demand and the changing trend of this demand based on the pilot pressure signal and its changing trend, and change the opening of the fluid valve through the output signal, thereby changing the flow of the fluid and achieving control of the hydraulic oil output.

[0004] However, this flow control method has a small flow adjustment range, low accuracy, drastic flow changes, and poor controllability. Summary of the invention

[0005] The embodiments of the present application provide a flow control method and system for hydraulic accessories of an electric excavator, and an electric excavator, which can widen the flow adjustment range, accurately and smoothly control the flow, and effectively improve the controllability.

[0006] In a first aspect, an embodiment of the present application provides a flow control method for a hydraulic attachment of an electric excavator, comprising:

[0007] Get the input gear information and maximum flow value;

[0008] Determine the maximum required displacement value according to the motor speed corresponding to the gear information and the maximum flow value;

[0009] According to the maximum required displacement, determining the oil supply mode of the main pump of the hydraulic system, the oil supply mode of the main pump including a single pump oil supply mode and a double pump oil supply mode, the main pump including a front pump and a rear pump;

[0010] Determine the current required displacement according to the voltage of the handle dial and the maximum required displacement;

[0011] According to the oil supply mode of the main pump and the current required displacement, the output currents of the front pump and the rear pump are determined respectively, and the openings of the corresponding reversing valves are controlled according to the output currents of the front pump and the rear pump.

[0012] In a possible implementation manner, determining the oil supply mode of the main pump of the hydraulic system according to the required maximum displacement includes:

[0013] Determining whether the maximum required displacement is greater than the maximum displacement of a single pump;

[0014] If it is greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a dual-pump oil supply mode, and the stop valve is controlled to be in the off state;

[0015] If it is not greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a single pump oil supply mode, and the stop valve is controlled to be in an open state;

[0016] Among them, the shut-off valve is arranged between the front pump oil channel and the oil tank of the hydraulic system. When the shut-off valve is in an open state, the rear pump of the main pump supplies oil to the accessories. When the shut-off valve is in a closed state, the front pump and the rear pump of the main pump jointly supply oil to the accessories.

[0017] In a possible implementation manner, when the oil supply mode of the main pump is a single-pump oil supply mode, determining the output currents of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement includes:

[0018] Determining whether the current required displacement is less than the minimum displacement of a single pump;

[0019] If it is less than the minimum displacement of a single pump, it is determined that the output currents of the front pump and the rear pump are both 0;

[0020] If it is not less than the minimum displacement of a single pump, the output current of the front pump is determined to be 0, and according to the preset correspondence table between the required displacement and the output current of the rear pump, the first target rear pump output current corresponding to the current required displacement is determined, and the output current of the rear pump is linearly adjusted to the first target rear pump output current.

[0021] In a possible implementation manner, when the oil supply mode of the main pump is a dual-pump oil supply mode, determining the output currents of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement includes:

[0022] Determine whether the current required displacement is greater than a first required displacement, the first required displacement being greater than a single-pump maximum displacement, and the difference between the first required displacement and the single-pump maximum displacement is less than or equal to a single-pump minimum displacement;

[0023] If it is not greater than the first required displacement, the output current of the front pump is determined to be 0, and the required displacement of the first rear pump is determined according to the difference between the current required displacement and the minimum displacement of the single pump, and the second target rear pump output current corresponding to the first rear pump required displacement is determined according to a preset correspondence table between required displacement and rear pump output current, and the output current of the rear pump is linearly adjusted to the second target rear pump output current;

[0024] If it is greater than the first required displacement, the third target rear pump output current corresponding to the maximum displacement of the single pump is determined according to the preset correspondence table between the required displacement and the rear pump output current; the first front pump required displacement is determined according to the difference between the current required displacement and the maximum displacement of the single pump, and the first target front pump output current corresponding to the first front pump required displacement is determined according to the preset correspondence table between the required displacement and the front pump output current, and the output current of the rear pump is linearly adjusted to the third target rear pump output current, and the output current of the front pump is linearly adjusted to the first target front pump output current.

[0025] In a possible implementation manner, when the oil supply mode of the main pump is a dual-pump oil supply mode, the output currents of the front pump and the rear pump are determined respectively according to the oil supply mode of the main pump and the current required displacement, and further includes:

[0026] Determine the second front pump required displacement and the second rear pump required displacement according to half of the current required displacement;

[0027] Determine a second target front pump output current corresponding to the second front pump demand displacement according to a preset correspondence table between demand displacement and front pump output current, and linearly adjust the output current of the front pump to the second target front pump output current;

[0028] According to a preset correspondence table between required displacement and rear pump output current, a fourth target rear pump output current corresponding to the second rear pump required displacement is determined, and the output current of the rear pump is linearly adjusted to the fourth target rear pump output current.

[0029] In a possible implementation manner, the outlets of the front pump and the rear pump are respectively provided with pressure acquisition devices, and after the opening of the corresponding reversing valve is controlled according to the output current of the front pump and the rear pump, the method further includes:

[0030] Using the pressure acquisition device to obtain the real-time pressure values ​​of the front pump and the rear pump;

[0031] Determining the total real-time power of the front pump and the rear pump according to the real-time pressure values ​​of the front pump and the rear pump;

[0032] Determining whether the total real-time power exceeds the power threshold corresponding to the gear information;

[0033] If the power threshold is not exceeded, the opening of the corresponding reversing valve continues to be controlled according to the output current of the front pump and the rear pump;

[0034] If the power threshold is exceeded, the output currents of the front pump and the rear pump are linearly reduced respectively until the total real-time power does not exceed the power threshold, or the output currents of the front pump and the rear pump are both reduced to 0.

[0035] In a possible implementation manner, determining the current required displacement according to the voltage of the handle dial and the maximum required displacement includes:

[0036] According to the voltage of the handle dial, the current displacement of the dial is determined;

[0037] The current required displacement is determined according to the current displacement and the maximum required displacement.

[0038] In a possible implementation manner, controlling the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump includes:

[0039] Determining a target reversing valve according to a direction corresponding to the current displacement;

[0040] The opening degree of the target reversing valve is controlled according to the output currents of the front pump and the rear pump.

[0041] In a second aspect, an embodiment of the present application provides a flow control system for a hydraulic attachment of an electric excavator, comprising: a controller, a display screen, and a dial control device, wherein the controller is connected to the display screen and the dial control device respectively via a CAN bus;

[0042] The display screen is used to receive the gear information and the maximum flow value input by the user, and send the gear information and the maximum flow value to the controller via the CAN bus;

[0043] The thumbwheel control device is used to generate a voltage signal according to the movement of the thumbwheel of the handle, and send the voltage signal to the controller via the CAN bus;

[0044] The controller comprises:

[0045] A processor, and a memory communicatively connected to the processor;

[0046] Memory is used to store computer executable instructions;

[0047] The processor is used to execute the computer-executable instructions stored in the memory to implement the flow control method of the hydraulic attachment of the electric excavator of the first aspect.

[0048] In a third aspect, an embodiment of the present application provides an electric excavator, comprising: a hydraulic system, a power system, and a flow control system as described in the second aspect;

[0049] The hydraulic system includes an oil tank, a main pump, a hydraulically controlled multi-way valve, accessories, and a pilot pressure reducing valve group, and the power system includes a motor and a motor driver;

[0050] The motor is directly connected to the main pump through a coupling. The main pump includes a front pump, a rear pump and a variable device. The variable device is driven by a solenoid valve. A gear pump is also installed on the motor shaft to provide pilot oil circuit pressure.

[0051] The hydraulically controlled multi-way valve contains two oil passages, the inlets of which are connected to the front pump and the rear pump of the main pump through pipelines, the front pump oil passage is connected to the oil tank through a stop valve, and the rear pump oil passage is connected to the oil passage outlet through a three-position six-way reversing valve to drive the accessories to work; when the stop valve is opened, the oil of the front pump directly returns to the oil tank, and the accessories are only supplied with oil by the rear pump; when the stop valve is closed, the accessories are supplied with oil by both the front pump and the rear pump;

[0052] The three solenoid valves in the pilot pressure reducing valve group provide pilot pressure to the stop valve and the reversing valve respectively. The pressure reducing solenoid valve and the main pump variable device solenoid valve are connected to the controller of the flow control system by a wiring harness;

[0053] The outlets of the front pump and the rear pump are respectively provided with pressure collection devices, and the pressure collection devices are communicatively connected with the controller.

[0054] The embodiments of the present application provide a flow control method, system and electric excavator for hydraulic accessories of an electric excavator, which can determine the maximum required displacement based on the input gear information and the maximum flow value, and determine the oil supply mode of the main pump based on the maximum required displacement, so as to judge the timing of the dual pump confluence, taking into account both energy saving and smooth operation. The oil supply mode includes a single pump oil supply mode and a dual pump oil supply mode, and the flow adjustment range is wide, and it can be set from 0 to the maximum displacement of the dual pumps, which improves the applicability of flow control. In addition, the required displacement is calculated according to the motor speed corresponding to the gear information, so that the flow output under different gears remains consistent, which improves the smoothness of flow control. Furthermore, after determining the maximum required displacement, the current required displacement can be determined based on the voltage of the handle dial and the maximum required displacement, so that accurate flow control can be performed according to the current required displacement, thereby improving the accuracy of flow control. Afterwards, the output currents of the front pump and the rear pump are determined respectively according to the oil supply mode and the current required displacement. The opening of the corresponding reversing valve is controlled according to the output currents of the front pump and the rear pump, so that the displacement of the dual pumps changes at the same time. The flow changes smoothly during fixed gear operation, effectively improving controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0056] Figure 1 A system architecture diagram of an embodiment of the present application;

[0057] Figure 2 This is a flow chart of a flow control method for hydraulic attachments of an electric excavator according to an embodiment of the present application;

[0058] Figure 3 A diagram showing a corresponding relationship between the required displacement and the output current according to an embodiment of the present application;

[0059] Figure 4 A schematic diagram of the structure of a flow control system for a hydraulic attachment of an electric excavator according to an embodiment of the present application;

[0060] Figure 5 A schematic structural diagram of a flow control system for a hydraulic attachment of an electric excavator according to another embodiment of the present application;

[0061] Figure 6 It is a structural schematic diagram of an electric excavator according to an embodiment of the present application.

[0062] Figure numerals: 1. oil tank; 2. motor; 3. main pump; 4. hydraulically controlled multi-way valve; 5. right overflow valve; 6. left overflow valve; 7. accessories; 8. left reversing valve; 9. right reversing valve; 10. stop valve; 11. controller; 12. display screen; 13. dial control device; 14. motor driver.

[0063] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0064] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0065] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0066] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned, and they should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0067] It should also be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0068] The flow control method, system and electric excavator of the electric excavator hydraulic accessories of the present application can be used in the field of engineering machinery technology, and can also be used in any field other than the field of engineering machinery technology, such as the field of electric excavator technology, etc. The application field of the flow control method, system and electric excavator of the electric excavator hydraulic accessories of the present application is not limited.

[0069] The flow control method, system and electric excavator of the hydraulic accessories of the electric excavator of the present application can be applied to the scenario where the hydraulic electric excavator controls the accessories through hydraulic oil. Any scenario involving controlling the output of hydraulic oil using the positive flow principle can be applied to the flow control method, system and electric excavator of the hydraulic accessories of the electric excavator of the present application.

[0070] First, the terms involved in this application are explained:

[0071] Flow Rate, in electric excavators, flow rate usually refers to the speed at which hydraulic oil flows in the hydraulic system. The flow rate of hydraulic oil determines the speed of action of hydraulic actuators (such as hydraulic cylinders and hydraulic motors). Flow rate is usually provided by the hydraulic pump and is measured in liters per minute (L / min). A higher flow rate means that the hydraulic system can transfer energy faster, thereby increasing the working speed of the electric excavator. Adjusting the flow rate can be achieved by adjusting the output of the hydraulic pump or using a flow control valve to adapt to different working requirements.

[0072] Displacement, in hydraulic systems, refers to the volume of fluid moved by a hydraulic pump or hydraulic motor in one working cycle. For hydraulic pumps, displacement determines how much hydraulic fluid can be delivered per revolution of the pump. Displacement is usually measured in cubic centimeters per revolution (cc / rev) or cubic inches per revolution (in3 / rev). The hydraulic pump of an electric excavator is usually a variable displacement pump, which means that the displacement of the pump can be adjusted as needed to optimize the efficiency and response speed of the system.

[0073] In the related technology, positive flow control with higher flow control accuracy is gradually becoming popular in electric excavators. During the positive flow control process, the pressures output by the main pump and the pilot operating handle are in direct proportion. The controller can determine the flow demand and the changing trend of this demand based on the pilot pressure signal and its changing trend, and change the opening of the fluid valve through the output signal, thereby changing the flow of the fluid and achieving control of the hydraulic oil output.

[0074] However, this flow control method has a small flow adjustment range, low accuracy, and drastic flow changes, and poor controllability. Specifically:

[0075] (1) This flow control method usually uses a single pump to supply oil, and the flow adjustment range is small.

[0076] (2) This flow control method usually adopts percentage control, and the flow rate at different gears is different, so the flow control accuracy is low; when operating at a fixed gear, the flow rate changes more drastically and the controllability is poor.

[0077] Based on the above technical problems, the inventive concept of the present application is to provide a flow control solution for hydraulic accessories of electric excavators that can broaden the flow adjustment range and accurately and smoothly control the flow.

[0078] The embodiment of the present application provides a flow control method, system and electric excavator for hydraulic attachments of an electric excavator, which can adopt two oil supply modes, single pump oil supply and dual pump oil supply, broaden the flow adjustment range, and can be set from 0 to the maximum displacement of the dual pumps, thereby improving the applicability of flow control. In addition, the maximum value of the required displacement can be determined and calculated according to the motor speed and maximum flow value corresponding to the gear information, so that the flow output under different gears remains consistent, and the smoothness of flow control is improved. Further, the oil supply mode of the main pump can be determined according to the maximum required displacement, so as to determine the timing of the dual pump confluence, taking into account energy saving and smooth operation. Afterwards, the output current of the front pump and the rear pump is determined respectively according to the oil supply mode and the current required displacement, thereby improving the accuracy of flow control; the opening of the corresponding reversing valve is controlled according to the output current of the front pump and the rear pump, so that the displacement of the dual pumps changes at the same time, and the flow changes smoothly when the gear is fixed, which effectively improves the controllability.

[0079] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0080] Figure 1 This is a system architecture diagram of an embodiment of the present application, such as Figure 1 As shown, the flow control system includes a controller, a display screen and a dial control device. The controller is connected to the display screen and the dial control device through the CAN bus, obtains the input gear information and maximum flow value from the display screen, and obtains the voltage of the handle dial from the dial control device. The controller determines the maximum required displacement according to the motor speed and maximum flow value corresponding to the gear information; determines the oil supply mode of the main pump of the hydraulic system according to the maximum required displacement; determines the current required displacement according to the voltage of the handle dial and the maximum required displacement; determines the output current of the front pump and the rear pump according to the oil supply mode of the main pump and the current required displacement, and controls the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump.

[0081] Figure 2 This is a flow chart of a flow control method for a hydraulic attachment of an electric excavator according to an embodiment of the present application. This embodiment uses a flow control system of a hydraulic attachment of an electric excavator as an execution subject to illustrate the flow control method for the hydraulic attachment of an electric excavator. Figure 2 As shown, the flow control method of the electric excavator hydraulic attachment may include the following steps:

[0082] S201: Obtain input gear information and maximum flow value.

[0083] In this embodiment, the flow control system of the electric excavator hydraulic attachment may include a controller, a display screen and a dial control device. The controller is connected to the display screen and the dial control device respectively through a CAN bus. The executor of this embodiment may specifically be the controller in the flow control system.

[0084] In this embodiment, when the operator needs to operate the attachments of the electric excavator to work, the corresponding gear information and maximum flow value can be input on the display screen, and the controller can obtain the gear information and maximum flow value input by the operator on the display screen through the CAN bus.

[0085] In this embodiment, the maximum flow value may be the maximum absolute value (L / min) of the flow required by the attachment of the electric excavator to complete the current work, and the operator may flexibly set it based on actual experience.

[0086] S202: Determine the maximum required displacement according to the motor speed and the maximum flow value corresponding to the gear information.

[0087] In this embodiment, after the controller obtains the gear information and the maximum flow value, it can calculate the motor speed according to the gear information. On the one hand, the speed signal corresponding to the motor speed can be sent to the motor driver through the CAN bus to control the motor to run at the target speed; on the other hand, the maximum required displacement can be determined according to the motor speed and the maximum flow value to perform subsequent flow control.

[0088] In this embodiment, the maximum required displacement can be calculated using the following formula (1):

[0089] q_max=(Q_max*k_l / n)*1000 (1)

[0090] Where q_max is the maximum required displacement (cc), Q_max is the maximum flow value entered on the display (L / min); k_l is the coefficient for correcting the flow when leakage is considered; and n is the motor speed (rpm).

[0091] In this embodiment, the required displacement is calculated according to the motor speed corresponding to the gear information, so that the flow output under different gears remains consistent, thereby improving the smoothness of flow control.

[0092] S203: Determine the oil supply mode of the main pump of the hydraulic system according to the maximum required displacement, where the oil supply mode of the main pump includes a single-pump oil supply mode and a dual-pump oil supply mode.

[0093] In this embodiment, the main pump includes a front pump and a rear pump.

[0094] In this embodiment, in the single-pump oil supply mode, the rear pump of the main pump supplies oil to the accessories; in the dual-pump oil supply mode, the front pump and the rear pump of the main pump jointly supply oil to the accessories.

[0095] In this embodiment, if the maximum required displacement is greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a dual-pump oil supply mode; if the maximum required displacement is not greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a single-pump oil supply mode.

[0096] In this embodiment, the single-pump oil supply mode and the dual-pump oil supply mode of the main pump can broaden the flow adjustment range, and can be set from 0 to the maximum displacement of the dual pumps, thereby improving the applicability of flow control.

[0097] S204: Determine the current required displacement according to the voltage of the handle dial and the maximum required displacement.

[0098] In this embodiment, the operator controls the attachment to work by using the handle dial, so the dial displacement can be determined according to the voltage of the handle dial, and the current required displacement can be determined using the dial displacement and the maximum required displacement.

[0099] In this embodiment, when the thumbwheel displacement calculated according to the voltage of the handle thumbwheel reaches the maximum, the current required displacement is the maximum required displacement.

[0100] In this embodiment, after determining the maximum required displacement, the oil supply mode of the main pump can be determined, thereby determining whether the attachment needs to be operated with a single pump or with two pumps. The current required displacement is determined based on the voltage of the handle dial and the maximum required displacement, so as to achieve more accurate flow control based on the required displacement of the current working condition, while taking into account energy saving and smooth operation.

[0101] S205: Determine the output current of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement.

[0102] In this embodiment, when the maximum required displacement is small (less than or equal to the maximum displacement of a single pump), a single pump is used to supply oil, and when the maximum required displacement is large (greater than the maximum displacement of a single pump), dual pumps are used to supply oil; the opening of the main valve core pilot pressure reducing valve is controlled according to the current required displacement; when the dual pumps are supplying oil, one of the pumps supplies oil at the maximum displacement, and the insufficient part is supplemented by the other pump; when the dual pumps are supplying oil, the two pumps enter a confluence state from the beginning of the action, and the displacement of the two pumps increases at the same time to ensure continuous and smooth flow change.

[0103] S206: Control the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump.

[0104] In this embodiment, after determining the output current of the front pump and the rear pump, the opening of the corresponding reversing valve can be controlled according to the output current of the front pump and the rear pump. In the dual-pump oil supply mode, the displacement of the dual pumps can be changed simultaneously. When operating in a fixed gear, the flow rate changes smoothly and the controllability is good.

[0105] In this embodiment, the maximum required displacement can be determined according to the input gear information and the maximum flow value, and the oil supply mode of the main pump can be determined according to the maximum required displacement, so as to judge the timing of the dual pump confluence, taking into account energy saving and smooth operation. The oil supply mode includes a single pump oil supply mode and a dual pump oil supply mode, and the flow adjustment range is wide, and can be set from 0 to the maximum displacement of the dual pumps, which improves the applicability of flow control.

[0106] In addition, the required displacement is calculated according to the motor speed corresponding to the gear information, so that the flow output under different gears remains consistent, improving the smoothness of flow control. Furthermore, after determining the maximum required displacement, the current required displacement can be determined according to the voltage of the handle dial and the maximum required displacement, so that accurate flow control can be performed according to the current required displacement, improving the accuracy of flow control. Afterwards, according to the oil supply mode and the current required displacement, the output current of the front pump and the rear pump are determined respectively, and the opening of the corresponding reversing valve is controlled according to the output current of the front pump and the rear pump, so that the displacement of the two pumps changes at the same time, and the flow changes smoothly when the gear is fixed, which effectively improves the controllability.

[0107] In a possible implementation, the above step S203 determines the oil supply mode of the main pump of the hydraulic system according to the maximum required displacement, which may include:

[0108] S11: Determine whether the maximum required displacement is greater than the maximum displacement of a single pump.

[0109] S12: If it is greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a dual-pump oil supply mode, and the stop valve is controlled to be in a closed state.

[0110] S13: If it is not greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a single pump oil supply mode, and the stop valve is controlled to be in an open state.

[0111] Among them, the stop valve is arranged between the front pump oil channel and the oil tank of the hydraulic system. When the stop valve is in the open state, the rear pump of the main pump supplies oil to the accessories. When the stop valve is in the closed state, the front pump and the rear pump of the main pump jointly supply oil to the accessories.

[0112] In this embodiment, the single pump maximum displacement of the front pump and the rear pump is the same, and the single pump maximum displacement is fixedly set according to the specifications of the pump.

[0113] In this embodiment, the stop valve is arranged between the front pump oil passage and the oil tank of the hydraulic system. When the stop valve is in an open state, the front pump oil will directly return to the oil tank.

[0114] In this embodiment, if the maximum required displacement is greater than the maximum displacement of a single pump, it means that the oil supply of a single pump cannot meet the working requirements of the attachment, and the front pump and the rear pump of the main pump need to jointly supply oil to the attachment. If the maximum required displacement is not greater than the maximum displacement of a single pump, it means that the oil supply of a single pump can meet the working requirements of the attachment, and only the rear pump of the main pump needs to supply oil to the attachment.

[0115] In this embodiment, the cut-off valve disposed between the front pump oil passage and the oil tank of the hydraulic system can be used to simply and accurately switch between the dual pump oil supply mode and the single pump oil supply mode. In addition, by comparing the maximum required displacement and the maximum single pump displacement, the main pump oil supply mode can be simply and accurately determined, thereby determining the timing of the dual pump confluence, taking into account both energy saving and smooth operation.

[0116] In a possible implementation, when the oil supply mode of the main pump is the single pump oil supply mode, the above step S205 determines the output current of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement, which may include:

[0117] S21: Determine whether the current required displacement is less than the minimum displacement of a single pump.

[0118] S22: If it is less than the minimum displacement of a single pump, it is determined that the output currents of the front pump and the rear pump are both 0.

[0119] S23: If it is not less than the minimum displacement of a single pump, determine that the output current of the front pump is 0, and determine the first target rear pump output current corresponding to the current demand displacement according to the preset correspondence table between the demand displacement and the rear pump output current, and linearly adjust the output current of the rear pump to the first target rear pump output current.

[0120] In this embodiment, when the output current is 0, the front pump / rear pump will discharge hydraulic oil at the minimum displacement of a single pump.

[0121] In this embodiment, the front pump and the rear pump have the same minimum displacement per pump, and the minimum displacement per pump is fixedly set according to the specifications of the pumps.

[0122] In this embodiment, when the oil supply mode of the main pump is the single pump oil supply mode, the stop valve is in the open state, the rear pump of the main pump supplies oil to the accessories, and the output current of the front pump is always 0, maintaining the minimum displacement of the single pump. If the current required displacement is less than the minimum displacement of the single pump, the output current of the rear pump is also 0, maintaining the minimum displacement of the single pump; if the current required displacement is not less than the minimum displacement of the single pump, according to the corresponding relationship table between the required displacement and the output current of the rear pump, the first target rear pump output current corresponding to the current required displacement can be simply and accurately determined. Furthermore, the output current of the rear pump can be linearly adjusted to the first target rear pump output current to further ensure the smoothness of the flow change.

[0123] In a possible implementation, when the oil supply mode of the main pump is the dual-pump oil supply mode, the above step S205 determines the output current of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement, and may include:

[0124] S31: Determine whether the current required displacement is greater than the first required displacement, the first required displacement is greater than the maximum displacement of the single pump, and the difference between the first required displacement and the maximum displacement of the single pump is less than or equal to the minimum displacement of the single pump.

[0125] S32: If it is not greater than the first required displacement, the output current of the front pump is determined to be 0, and the required displacement of the first rear pump is determined according to the difference between the current required displacement and the minimum displacement of the single pump, and the second target rear pump output current corresponding to the first rear pump required displacement is determined according to the preset correspondence table between the required displacement and the rear pump output current, and the output current of the rear pump is linearly adjusted to the second target rear pump output current.

[0126] S33: If it is greater than the first required displacement, then according to the preset correspondence table between the required displacement and the rear pump output current, determine the third target rear pump output current corresponding to the maximum displacement of the single pump; according to the difference between the current required displacement and the maximum displacement of the single pump, determine the first front pump required displacement, and according to the preset correspondence table between the required displacement and the front pump output current, determine the first target front pump output current corresponding to the first front pump required displacement, and linearly adjust the output current of the rear pump to the third target rear pump output current, and linearly adjust the output current of the front pump to the first target front pump output current.

[0127] In this embodiment, when the oil supply mode of the main pump is the dual-pump oil supply mode, the stop valve is closed, the dual pumps enter a merging state, and the displacements of the two pumps increase simultaneously, ensuring continuous and smooth flow conversion.

[0128] In this embodiment, the first required displacement is slightly larger than the maximum displacement of a single pump. Those skilled in the art may flexibly set the first required displacement according to actual conditions, as long as the first required displacement is larger than the maximum displacement of a single pump and the difference between the first required displacement and the maximum displacement of a single pump is less than or equal to the minimum displacement of a single pump.

[0129] In this embodiment, since the front pump will also output at the minimum displacement of a single pump when the output current is 0, therefore, when the current required displacement is not greater than the first required displacement, it is necessary to consider the minimum displacement of a single pump output by the front pump, and determine the required displacement of the first rear pump according to the difference between the current required displacement and the minimum displacement of a single pump, thereby further improving the accuracy of flow control. When the current required displacement is greater than the first required displacement, the rear pump can output at the maximum displacement of a single pump, and the remaining part can be supplemented by the front pump. In addition, according to the corresponding relationship table between the required displacement and the output current of the front pump / rear pump, the corresponding target front pump / rear pump output current can be simply and accurately determined. Furthermore, the output current of the front pump / rear pump can be linearly adjusted to the target front pump / rear pump output current, thereby further ensuring the smoothness of flow changes.

[0130] In a possible implementation, when the oil supply mode of the main pump is the dual-pump oil supply mode, the above step S205 determines the output current of the front pump and the rear pump respectively according to the oil supply mode of the main pump and the current required displacement, and may include:

[0131] S41: Determine the second front pump required displacement and the second rear pump required displacement according to half of the current required displacement.

[0132] S42: Determine a second target front pump output current corresponding to the second front pump demand displacement according to a preset correspondence table between demand displacement and front pump output current, and linearly adjust the output current of the front pump to the second target front pump output current.

[0133] S43: Determine a fourth target rear pump output current corresponding to the second rear pump demand displacement according to a preset correspondence table between demand displacement and rear pump output current, and linearly adjust the output current of the rear pump to the fourth target rear pump output current.

[0134] In this embodiment, the correspondence table between the preset required displacement and the output current of the front pump / rear pump can be obtained by those skilled in the art based on actual tests.

[0135] For example, Figure 3 FIG. 1 is a diagram showing a corresponding relationship between the required displacement and the output current according to an embodiment of the present application. Figure 3 As shown in the figure, (a) is the correspondence table between the demand displacement and the output current of the rear pump, and (b) is the correspondence table between the demand displacement and the output current of the front pump. After determining the demand displacement allocated to the rear pump, the output current of the rear pump can be accurately determined by looking up the correspondence table (a); similarly, after determining the demand displacement allocated to the front pump, the output current of the front pump can be accurately determined by looking up the correspondence table (b).

[0136] In this embodiment, when the oil supply mode of the main pump is the dual-pump oil supply mode, the stop valve is closed, the dual pumps enter the confluence state, the front pump and the rear pump can evenly distribute the current required displacement, and the displacement of the two pumps increases at the same time to ensure continuous and smooth flow change. Furthermore, the output current of the front pump / rear pump can be linearly adjusted to the target front pump / rear pump output current to further ensure the smoothness of flow change.

[0137] In a possible implementation, the above step S204 determines the current required displacement according to the voltage of the handle dial and the maximum required displacement, which may include:

[0138] S51: Determine the current displacement of the thumbwheel according to the voltage of the thumbwheel of the handle.

[0139] S52: Determine the current required displacement according to the current displacement and the maximum required displacement.

[0140] In this embodiment, the flow rate of the accessory pipeline can be controlled by the displacement of the dial on the handle. The greater the displacement of the dial, the greater the current of the regulator solenoid valve on the main pump, that is, the greater the displacement of the main pump. At the same time, the greater the current of the main valve core pilot pressure reducing valve, the greater the pilot pressure, and the larger the main valve core opening.

[0141] In this embodiment, the current displacement of the handle dial can be accurately determined based on the voltage signal transmitted by the handle dial; the current required displacement can be simply and accurately determined based on the current displacement and the maximum required displacement, thereby using the current required displacement for accurate flow control.

[0142] In a possible implementation, the above step S206 of controlling the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump may include:

[0143] S61: Determine the target reversing valve according to the direction corresponding to the current displacement.

[0144] S62: Control the opening of the target reversing valve according to the output current of the front pump and the rear pump.

[0145] In this embodiment, when the dial is turned to the left, the current displacement direction is left, and the left reversing solenoid valve outputs; when the dial is turned to the right, the current displacement direction is right, and the right reversing solenoid valve outputs.

[0146] In this embodiment, the target reversing valve can be determined simply and accurately according to the direction corresponding to the current displacement, and the opening of the target reversing valve is controlled according to the output current of the front pump and the rear pump, so that the displacement of the dual pumps changes at the same time, and the flow rate changes smoothly during fixed gear operation, effectively improving the controllability.

[0147] In a possible implementation, the outlets of the front pump and the rear pump may be provided with pressure collection devices respectively. After the above step S206 controls the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump, the following may also be included:

[0148] S71: Using the pressure acquisition device to obtain the real-time pressure values ​​of the front pump and the rear pump.

[0149] S72: Determine the total real-time power of the front pump and the rear pump according to the real-time pressure values ​​of the front pump and the rear pump.

[0150] S73: Determine whether the total real-time power exceeds the power threshold corresponding to the gear information.

[0151] S74: If the power threshold is not exceeded, the opening of the corresponding reversing valve continues to be controlled according to the output current of the front pump and the rear pump.

[0152] S75: If the power threshold is exceeded, the output currents of the front pump and the rear pump are linearly reduced respectively until the total real-time power does not exceed the power threshold, or the output currents of the front pump and the rear pump are both reduced to 0.

[0153] In this embodiment, the specific type of the pressure collection device can be flexibly set by those skilled in the art, as long as the pressure collection device can collect the pressure value of the front pump / rear pump in real time.

[0154] In this embodiment, the pressure acquisition device can be connected to the controller for communication, so as to send the acquired pressure value to the controller in real time.

[0155] In this embodiment, different gears may correspond to a power threshold respectively. The specific power threshold may be flexibly set by technicians in this field according to actual conditions, and no limitation is made here.

[0156] In this embodiment, the total real-time power of the front pump and the rear pump can be calculated using the following formulas (2)-(6):

[0157] P total = P_real before + P_real after (2)

[0158] P_realfront = p_realfront * q_realfront / 62.8 (3)

[0159] P_real = p_real*q_real / 62.8 (4)

[0160] q_realfront = (q_max - q_min) * (I_realfront - 400) / 350 + q_min (5)

[0161] q_real = (q_max - q_min) * (I_real - 400) / 350 + q_min (6)

[0162] Among them, Ptotal is the total real-time power of the front pump and the rear pump, P_realfront is the real-time power of the front pump, and P_realafter is the real-time power of the rear pump; p_realfront is the real-time pressure value of the front pump, unit is bar, and p_realafter is the real-time pressure value of the rear pump; q_realfront is the displacement corresponding to the real-time output current of the front pump, unit is cc, and q_realafter is the displacement corresponding to the real-time output current of the rear pump; I_realfront is the real-time output current of the front pump, unit is mA, and I_realafter is the real-time output current of the rear pump; q_max is the maximum displacement of a single pump, and q_min is the minimum displacement of a single pump.

[0163] In this embodiment, if the total real-time power exceeds the power threshold, the output currents of the front pump and the rear pump are linearly reduced at the same time, and the reduction degree of the front pump and the rear pump is the same, until the total real-time power of the front pump and the rear pump does not exceed the power threshold. If during this process, the output current of the front pump / rear pump has been reduced to 0, and the total real-time power still exceeds the power threshold, the output current of the other pump continues to be linearly reduced until the total real-time power does not exceed the power threshold, or the output currents of the front pump and the rear pump are both reduced to 0.

[0164] In this embodiment, the real-time pressure values ​​of the front pump and the rear pump can be collected by using the pressure collection devices respectively arranged at the outlets of the front pump and the rear pump, and the total real-time power of the front pump and the rear pump can be calculated according to the real-time pressure values. By comparing the total real-time power with the power threshold, and linearly reducing the output current of the front pump and the rear pump when the total real-time power exceeds the power threshold, the total real-time power is kept at a state of not exceeding the power threshold, ensuring constant power and avoiding high-power damage.

[0165] The flow control method of the hydraulic attachment of the electric excavator of the present application is described below with a specific embodiment.

[0166] In a specific embodiment, an operator wants to operate an electric excavator to perform an excavation operation. The operator enters the gear information and the maximum flow value of the operation on the display screen of the electric excavator and operates the handle dial. The specific flow control process during the operation is as follows:

[0167] In the first step, the controller of the electric excavator flow control system obtains the gear information and maximum flow value entered by the operator in the display screen.

[0168] In the second step, the controller determines the maximum required displacement based on the motor speed and maximum flow value corresponding to the gear information.

[0169] In the third step, the controller determines that the maximum required displacement is greater than the maximum displacement of a single pump, and then determines that the oil supply mode of the main pump of the hydraulic system is a dual-pump oil supply mode, and controls the shut-off valve to be closed.

[0170] In the fourth step, the controller obtains the voltage of the handle dial transmitted by the dial control device, and determines the current displacement of the dial according to the voltage of the handle dial; and determines the current required displacement according to the current displacement and the maximum required displacement.

[0171] In the fifth step, the controller determines that the current required displacement is greater than the first required displacement (the first required displacement is slightly greater than the maximum displacement of a single pump), then determines that the rear pump outputs at the maximum displacement of a single pump, and determines the target rear pump output current corresponding to the maximum displacement of a single pump according to the preset correspondence table between the required displacement and the rear pump output current.

[0172] In the sixth step, the controller determines the front pump demand displacement according to the difference between the current demand displacement and the maximum displacement of the single pump, and determines the target front pump output current corresponding to the front pump demand displacement according to the preset correspondence table between the demand displacement and the front pump output current.

[0173] In the seventh step, the controller linearly adjusts the output current of the rear pump to the target rear pump output current, and linearly adjusts the output current of the front pump to the target front pump output current; and according to the direction corresponding to the current displacement, determines that the target reversing valve is the left reversing valve, and controls the opening of the left reversing valve according to the output current of the front pump and the rear pump.

[0174] In the eighth step, the controller uses the pressure collection devices respectively arranged at the outlets of the front pump and the rear pump to collect the real-time pressure values ​​of the front pump and the rear pump, and determines the total real-time power of the front pump and the rear pump according to the real-time pressure values ​​of the front pump and the rear pump, and determines that the total real-time power exceeds the power threshold corresponding to the gear information at a certain moment; then, the output current of the front pump and the rear pump is linearly reduced at the same time until the total real-time power is in a state of not exceeding the power threshold.

[0175] Figure 4 FIG. 1 is a schematic diagram of a flow control system for a hydraulic attachment of an electric excavator according to an embodiment of the present application. Figure 4 As shown, the flow control system of the hydraulic attachment of the electric excavator includes: an acquisition module 41, which is used to obtain the input gear information and the maximum flow value; a processing module 42, which is used to determine the maximum required displacement according to the motor speed and the maximum flow value corresponding to the gear information; according to the maximum required displacement, determine the oil supply mode of the main pump of the hydraulic system, the oil supply mode of the main pump includes a single pump oil supply mode and a double pump oil supply mode, and the main pump includes a front pump and a rear pump; according to the voltage of the handle dial and the maximum required displacement, determine the current required displacement; according to the oil supply mode of the main pump and the current required displacement, respectively determine the output current of the front pump and the rear pump, and control the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump.

[0176] The flow control system of the electric excavator hydraulic attachment provided in the embodiment of the present application can execute the technical solution shown in the above method embodiment, and its implementation principle and beneficial effects are similar, which will not be repeated here.

[0177] Figure 5 FIG. 1 is a structural schematic diagram of a flow control system of a hydraulic attachment of an electric excavator according to another embodiment of the present application. Figure 5 As shown, the flow control system of the hydraulic attachment of the electric excavator includes: a controller, a display screen and a dial control device, the controller is connected to the display screen and the dial control device respectively through the CAN bus; the display screen is used to receive the gear information and the maximum flow value input by the user, and send the gear information and the maximum flow value to the controller through the CAN bus; the dial control device is used to generate a voltage signal according to the movement of the handle dial, and send the voltage signal to the controller through the CAN bus;

[0178] The controller includes: a processor 501, and a memory 502 that is communicatively connected to the processor 501; the memory 502 stores computer-executable instructions; the processor 501 executes the computer-executable instructions stored in the memory 502 to implement the steps of the flow control method of the hydraulic attachment of the electric excavator in the above-mentioned method embodiments.

[0179] The flow control system of the hydraulic attachment of the electric excavator can be independent or a part of the control system of the electric excavator. The processor 501 and the memory 502 can adopt the existing hardware of the control system of the electric excavator.

[0180] In the flow control system of the hydraulic attachment of the electric excavator, the memory 502 and the processor 501 are directly or indirectly electrically connected to realize data transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines, such as through a bus connection. The memory 502 stores computer-executable instructions for implementing the data access control method, including at least one software function module that can be stored in the memory 502 in the form of software or firmware. The processor 501 executes various functional applications and data processing by running the software programs and modules stored in the memory 502.

[0181] The memory 502 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electric erasable programmable read-only memory (EEPROM), etc. The memory 502 is used to store programs, and the processor 501 executes the programs after receiving the execution instruction. Furthermore, the software programs and modules in the above-mentioned memory 502 may also include an operating system, which may include various software components and / or drivers for managing system tasks (such as memory management, storage device control, power management, etc.), and may communicate with various hardware or software components to provide an operating environment for other software components.

[0182] The processor 501 may be an integrated circuit chip having the ability to process signals. The processor 501 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc. The methods, steps, and logic diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or any conventional processor.

[0183] Figure 6 FIG. 1 is a schematic diagram of the structure of an electric excavator according to an embodiment of the present application. Figure 6 As shown, the electric excavator includes: a hydraulic system, a power system, and Figure 5 The flow control system shown;

[0184] The hydraulic system includes an oil tank 1 , a main pump 3 , a hydraulically controlled multi-way valve 4 , accessories 7 , and a pilot pressure reducing valve group, and the power system includes a motor 2 and a motor driver 14 .

[0185] The motor 2 is directly connected to the main pump 3 through a coupling. The main pump 3 includes a front pump P1, a rear pump P2 and a variable device. The variable device is driven by a solenoid valve. A gear pump is also installed on the motor shaft to provide pilot oil circuit pressure.

[0186] The hydraulically controlled multi-way valve 4 contains two oil passages, the inlets of which are connected to the front pump P1 and the rear pump P2 of the main pump 3 through pipelines, the front pump oil passage is connected to the oil tank 1 through the stop valve 10, and the rear pump oil passage is connected to the oil passage outlet through the three-position six-way reversing valve to drive the accessory 7 to work; when the stop valve 10 is opened, the front pump oil directly returns to the oil tank 1, and the accessory 7 is only supplied with oil by the rear pump P2; when the stop valve 10 is closed, the accessory 7 is supplied with oil by both the front pump P1 and the rear pump P2, and the accessory 7 is also connected to the right overflow valve 5 and the left overflow valve 6, respectively.

[0187] The three solenoid valves in the pilot pressure reducing valve group provide pilot pressure to the stop valve 10, the left reversing valve (left reversing valve pilot pressure reducing valve) 8, and the right reversing valve (right reversing valve pilot pressure reducing valve) 9 respectively. The pressure reducing solenoid valve and the main pump variable device solenoid valve are connected to the controller 11 of the flow control system by a wiring harness.

[0188] The controller 11 is connected to the display screen 12 and the dial control device 13 respectively through the CAN bus, and the controller 11 is also connected to the motor driver 14 through the CAN bus.

[0189] The outlets of the front pump P1 and the rear pump P2 are respectively provided with pressure collection devices, and the pressure collection devices are communicatively connected with the controller.

[0190] In this embodiment, the front pump oil passage is connected to the oil tank through a stop valve, and the rear pump oil passage is connected to the attachment through a three-position six-way reversing valve. When the stop valve is in an open state, the rear pump of the main pump supplies oil to the attachment, and when the stop valve is in a closed state, the front pump and the rear pump of the main pump jointly supply oil to the attachment. Through such a setting, the stop valve can be used to switch between the two oil supply modes of single pump supply and double pump supply, thereby widening the flow adjustment range, and the flow rate can be set from 0 to the maximum displacement of the double pumps, thereby improving the applicability of flow control. In addition, the controller of the flow control system is also connected to the display screen and the dial control device through the CAN bus, so as to obtain the gear information and maximum flow value input by the display screen, and the voltage of the handle dial collected by the dial control device, and then determine the output current of the front pump and the rear pump according to the gear information, the maximum flow value and the voltage of the dial, and control the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump, so as to perform accurate and smooth flow control, effectively improving the controllability. Furthermore, the outlets of the front pump and the rear pump are respectively provided with pressure collection devices which are communicatively connected to the controller. The controller can calculate the total real-time power of the front pump and the rear pump based on the real-time pressure value, and linearly reduce the output current of the front pump and the rear pump when it is detected that the total real-time power exceeds the power threshold, so that the total real-time power of the front pump and the rear pump is always maintained at a state not exceeding the power threshold, thereby ensuring constant power and avoiding high-power damage.

[0191] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the steps of each method embodiment of the present application.

[0192] An embodiment of the present application further provides a computer program product, including a computer program, which implements the steps of each method embodiment of the present application when executed by a processor.

[0193] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present application.

[0194] It should be further noted that, although the various steps in the flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowchart may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0195] It should be understood that the above-mentioned device embodiments are only illustrative, and the device of the present application can also be implemented in other ways. For example, the division of units / modules in the above-mentioned embodiments is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units, modules or components can be combined, or can be integrated into another system, or some features can be ignored or not executed.

[0196] In addition, unless otherwise specified, each functional unit / module in each embodiment of the present application may be integrated into one unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated together. The above-mentioned integrated unit / module may be implemented in the form of hardware or in the form of a software program module.

[0197] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0198] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

[0199] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A flow control method for hydraulic attachments of an electric excavator, characterized in that: include: Get the input gear information and maximum flow value; Determine the maximum required displacement value according to the motor speed corresponding to the gear information and the maximum flow value; According to the maximum required displacement, determining the oil supply mode of the main pump of the hydraulic system, the oil supply mode of the main pump including a single pump oil supply mode and a double pump oil supply mode, the main pump including a front pump and a rear pump; Determine the current required displacement according to the voltage of the handle dial and the maximum required displacement; According to the oil supply mode of the main pump and the current required displacement, the output currents of the front pump and the rear pump are determined respectively, and the openings of the corresponding reversing valves are controlled according to the output currents of the front pump and the rear pump.

2. The flow control method of the hydraulic attachment of an electric excavator according to claim 1, characterized in that: The step of determining the oil supply mode of the main pump of the hydraulic system according to the maximum required displacement comprises: Determining whether the maximum required displacement is greater than the maximum displacement of a single pump; If it is greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a dual-pump oil supply mode, and the stop valve is controlled to be in the off state; If it is not greater than the maximum displacement of a single pump, the oil supply mode of the main pump of the hydraulic system is determined to be a single pump oil supply mode, and the stop valve is controlled to be in an open state; Among them, the shut-off valve is arranged between the front pump oil channel and the oil tank of the hydraulic system. When the shut-off valve is in an open state, the rear pump of the main pump supplies oil to the accessories. When the shut-off valve is in a closed state, the front pump and the rear pump of the main pump jointly supply oil to the accessories.

3. The flow control method of the hydraulic attachment of an electric excavator according to claim 2, characterized in that: When the oil supply mode of the main pump is the single pump oil supply mode, the output currents of the front pump and the rear pump are determined respectively according to the oil supply mode of the main pump and the current required displacement, including: Determining whether the current required displacement is less than the minimum displacement of a single pump; If it is less than the minimum displacement of a single pump, it is determined that the output currents of the front pump and the rear pump are both 0; If it is not less than the minimum displacement of a single pump, the output current of the front pump is determined to be 0, and according to the preset correspondence table between the required displacement and the output current of the rear pump, the first target rear pump output current corresponding to the current required displacement is determined, and the output current of the rear pump is linearly adjusted to the first target rear pump output current.

4. The flow control method for hydraulic attachments of an electric excavator according to claim 2, characterized in that: When the oil supply mode of the main pump is the dual-pump oil supply mode, the output currents of the front pump and the rear pump are determined respectively according to the oil supply mode of the main pump and the current required displacement, including: Determine whether the current required displacement is greater than a first required displacement, the first required displacement being greater than a single-pump maximum displacement, and the difference between the first required displacement and the single-pump maximum displacement is less than or equal to a single-pump minimum displacement; If it is not greater than the first required displacement, the output current of the front pump is determined to be 0, and the required displacement of the first rear pump is determined according to the difference between the current required displacement and the minimum displacement of the single pump, and the second target rear pump output current corresponding to the first rear pump required displacement is determined according to a preset correspondence table between required displacement and rear pump output current, and the output current of the rear pump is linearly adjusted to the second target rear pump output current; If it is greater than the first required displacement, the third target rear pump output current corresponding to the maximum displacement of the single pump is determined according to the preset correspondence table between the required displacement and the rear pump output current; the first front pump required displacement is determined according to the difference between the current required displacement and the maximum displacement of the single pump, and the first target front pump output current corresponding to the first front pump required displacement is determined according to the preset correspondence table between the required displacement and the front pump output current, and the output current of the rear pump is linearly adjusted to the third target rear pump output current, and the output current of the front pump is linearly adjusted to the first target front pump output current.

5. The flow control method of the hydraulic attachment of an electric excavator according to claim 2, characterized in that: When the oil supply mode of the main pump is a dual-pump oil supply mode, the output currents of the front pump and the rear pump are determined respectively according to the oil supply mode of the main pump and the current required displacement, and further includes: Determine the second front pump required displacement and the second rear pump required displacement according to half of the current required displacement; Determine a second target front pump output current corresponding to the second front pump demand displacement according to a preset correspondence table between demand displacement and front pump output current, and linearly adjust the output current of the front pump to the second target front pump output current; According to a preset correspondence table between required displacement and rear pump output current, a fourth target rear pump output current corresponding to the second rear pump required displacement is determined, and the output current of the rear pump is linearly adjusted to the fourth target rear pump output current.

6. The flow control method for hydraulic attachments of an electric excavator according to any one of claims 1 to 5, characterized in that: The outlets of the front pump and the rear pump are respectively provided with pressure collection devices, and after the opening of the corresponding reversing valve is controlled according to the output current of the front pump and the rear pump, the method further includes: Using the pressure acquisition device to obtain the real-time pressure values ​​of the front pump and the rear pump; Determining the total real-time power of the front pump and the rear pump according to the real-time pressure values ​​of the front pump and the rear pump; Determining whether the total real-time power exceeds the power threshold corresponding to the gear information; If the power threshold is not exceeded, the opening of the corresponding reversing valve continues to be controlled according to the output current of the front pump and the rear pump; If the power threshold is exceeded, the output currents of the front pump and the rear pump are linearly reduced respectively until the total real-time power does not exceed the power threshold, or the output currents of the front pump and the rear pump are both reduced to 0.

7. The flow control method for hydraulic attachments of an electric excavator according to any one of claims 1 to 5, characterized in that: Determining the current required displacement according to the voltage of the handle dial and the maximum required displacement includes: According to the voltage of the handle dial, the current displacement of the dial is determined; The current required displacement is determined according to the current displacement and the maximum required displacement.

8. The flow control method for hydraulic attachments of an electric excavator according to claim 7, characterized in that: The controlling the opening of the corresponding reversing valve according to the output current of the front pump and the rear pump comprises: Determining a target reversing valve according to a direction corresponding to the current displacement; The opening degree of the target reversing valve is controlled according to the output currents of the front pump and the rear pump.

9. A flow control system for hydraulic attachments of an electric excavator, characterized in that: include: A controller, a display screen and a dial control device, wherein the controller is connected to the display screen and the dial control device respectively via a CAN bus; The display screen is used to receive the gear information and the maximum flow value input by the user, and send the gear information and the maximum flow value to the controller via the CAN bus; The thumbwheel control device is used to generate a voltage signal according to the movement of the thumbwheel of the handle, and send the voltage signal to the controller via the CAN bus; The controller comprises: A processor, and a memory communicatively connected to the processor; The memory is used to store computer-executable instructions; The processor is used to execute the computer-executable instructions stored in the memory to implement the flow control method for the hydraulic attachment of an electric excavator according to any one of claims 1-8.

10. An electric excavator, characterized in that: include: A hydraulic system, a power system, and a flow control system as claimed in claim 9; The hydraulic system includes an oil tank, a main pump, a hydraulically controlled multi-way valve, accessories, and a pilot pressure reducing valve group, and the power system includes a motor and a motor driver; The motor is directly connected to the main pump through a coupling. The main pump includes a front pump, a rear pump and a variable device. The variable device is driven by a solenoid valve. A gear pump is also installed on the motor shaft to provide pilot oil circuit pressure. The hydraulically controlled multi-way valve contains two oil passages, the inlets of which are connected to the front pump and the rear pump of the main pump through pipelines, the front pump oil passage is connected to the oil tank through a stop valve, and the rear pump oil passage is connected to the oil passage outlet through a three-position six-way reversing valve to drive the accessories to work; when the stop valve is opened, the oil of the front pump directly returns to the oil tank, and the accessories are only supplied with oil by the rear pump; when the stop valve is closed, the accessories are supplied with oil by both the front pump and the rear pump; The three solenoid valves in the pilot pressure reducing valve group provide pilot pressure to the stop valve and the reversing valve respectively. The pressure reducing solenoid valve and the main pump variable device solenoid valve are connected to the controller of the flow control system by a wiring harness; The outlets of the front pump and the rear pump are respectively provided with pressure collection devices, and the pressure collection devices are communicatively connected with the controller.

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