Electrically controlled hydraulic control system for excavator, electrically controlled excavator and control method

Abstract

The present application relates to the technical field of excavators, and discloses an electrically-controlled excavator hydraulic control system, an electrically-controlled excavator and a control method, which adopts a single variable pump, reduces the number of pumps and lowers the cost; the working current of each pilot electromagnetic valve is adjusted by an electrically-controlled handle to adjust the opening degree of the pilot electromagnetic valve, and the displacement of the variable pump is adjusted according to the maximum current value in the working current of all the pilot electromagnetic valves, so that the displacement of the variable pump can meet the actual working demand, the response speed is fast, and the operation cost is reduced. The electrically-controlled excavator flat ground control method provided by the present application obtains the relationship between the working current of the bucket rod recovery pilot electromagnetic valve and the working current of the boom lifting pilot electromagnetic valve during flat ground operation by finding the speed matching relationship between the bucket rod oil cylinder and the boom oil cylinder, and adjusts the opening degree of the bucket rod recovery pilot electromagnetic valve and the boom lifting pilot electromagnetic valve by the relationship combined with the boom demand current and the bucket rod demand current, respectively, so that better flat ground operability is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of excavators, in particular to an electrically-controlled excavator hydraulic control system, an electrically-controlled excavator and a control method. BACKGROUND

[0002] The existing fully-electrically-controlled medium / large excavator adopts a double-pump double-circuit system. In order to improve the coordination of the bucket rod and the boom action, the double-pump system is used for flow control and regeneration control to realize the coordinated action of the bucket rod and the boom during grading operation, that is, by controlling the bucket rod flow and the bucket rod regeneration, the speed of the bucket rod relative to the boom action is different during the initial grading and the later grading, the action coordination is improved, and the phenomena such as nodding and grooving during grading are eliminated.

[0003] However, the double-pump system has the defects of complex structure, large number of parts and high cost, and is not suitable for small excavators. In addition, the front pump and the rear pump are both provided with a single-pump load-sensitive system for adjusting the displacement of the two pumps, but have the problems of slow response speed and high oil consumption. SUMMARY

[0004] One of the purposes of the present application is to provide an electrically-controlled excavator hydraulic control system and an electrically-controlled excavator, which can simplify the structure of the electrically-controlled excavator hydraulic control system, reduce the number of parts, improve the response speed, and reduce the manufacturing cost and operating cost of the excavator.

[0005] Another purpose of the present application is to provide an excavator control method, which can improve the debugging efficiency during grading operation debugging and reduce the debugging cost.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The electrically-controlled excavator hydraulic control system comprises a variable pump, a plurality of working components and a plurality of main control valves corresponding to the plurality of working components, the variable pump being capable of controlling the extension and retraction of the piston rod of the corresponding working component through the main control valve; the plurality of working components comprise two working cylinders, namely a boom cylinder and a bucket rod cylinder; the main control valve has two main control pilot ends, and further comprises:

[0008] A pilot oil circuit corresponding to the main control pilot end, each main control pilot end being in communication with one end of the corresponding pilot oil circuit and in communication with the other pilot oil circuits at the other end;

[0009] A pilot electromagnetic valve corresponding to the main control pilot end and arranged on the corresponding pilot oil circuit, the opening degree of the pilot electromagnetic valve being adjustable; the pilot electromagnetic valve has an electromagnetic pilot end and a hydraulic control pilot end, and the hydraulic control pilot end of the pilot electromagnetic valve is in communication with the corresponding main control pilot end;

[0010] An operation part is electrically connected with each of the electromagnetic pilot ends, and is configured to control working current of each of the pilot electromagnetic valves to adjust opening degree of the pilot electromagnetic valves; the operation part is electrically connected with the variable pump, and is configured to adjust displacement of the variable pump according to maximum current value among working currents of all the pilot electromagnetic valves.

[0011] As a preferred technical scheme of the above-mentioned electrically-controlled hydraulic control system of excavator, one pressure compensation valve is correspondingly arranged for each of the working components, a first compensation pilot end of each of the pressure compensation valves is communicated to form a first pressure compensation oil path, and the first compensation pilot end is provided with a pressure compensation return spring.

[0012] The main control valve has a main control working position, when the main control valve is in the main control working position, the oil outlet of the variable pump is communicated with the second compensation pilot end of the pressure compensation valve through the main control valve, the oil inlet of the working component is communicated with the oil tank through the main control valve and the pressure compensation valve to form an oil inlet channel, and the oil outlet of the working component is communicated with the oil tank through the main control valve to form an oil return channel.

[0013] The pressure compensation valve has a pressure compensation left position, a pressure compensation middle position and a pressure compensation right position, when the pressure compensation valve is in the pressure compensation left position, the oil inlet channel is communicated and the oil inlet channel is communicated with the first compensation pilot end of the pressure compensation valve through a compensation orifice on a valve core of the pressure compensation valve; when the pressure compensation valve is in the pressure compensation middle position, the oil inlet channel flows through the compensation orifice; and when the pressure compensation valve is in the pressure compensation right position, the oil inlet channel is disconnected.

[0014] As a preferred technical scheme of the above-mentioned electrically-controlled hydraulic control system of excavator, the plurality of working components further include a bucket oil cylinder, a traveling motor and a slewing motor.

[0015] As a preferred technical scheme of the above-mentioned electrically-controlled hydraulic control system of excavator, one cartridge valve is correspondingly arranged for each of the working oil cylinders.

[0016] The cartridge valve has two cartridge working oil ports, one of the cartridge working oil ports is communicated with a rod cavity of the corresponding working oil cylinder, and the other cartridge working oil port is selectively communicated with the oil tank or the rodless cavity of the corresponding working oil cylinder through the corresponding main control valve when the main control valve is in the main control working position.

[0017] A spring cavity of each of the cartridge valves is communicated to form a second pressure compensation oil path through the corresponding main control valve, and the first pressure compensation oil path is communicated with the second pressure compensation oil path through a compensation orifice.

[0018] As a preferred technical scheme of the above-mentioned electrically-controlled hydraulic excavator hydraulic control system, a throttle hole is arranged on the spool of the cartridge valve, and the rod cavity of the working oil cylinder is communicated with the spring cavity of the cartridge valve through the throttle hole.

[0019] As a preferred technical scheme of the above-mentioned electrically-controlled hydraulic excavator hydraulic control system, the main control valve corresponding to the boom cylinder is a boom main control valve, a boom throttle hole is arranged on the spool of the boom main control valve, and a boom check valve is integrated in the boom main control valve.

[0020] When the boom main control valve is in the main control working position and the piston rod of the boom cylinder is extended, the rod cavity of the boom cylinder can be communicated with the oil tank through the boom throttle hole and is unidirectionally communicated with the rodless cavity of the boom cylinder through the boom check valve.

[0021] The application further provides an electrically-controlled hydraulic excavator comprising the electrically-controlled hydraulic excavator hydraulic control system of any of the above-mentioned schemes.

[0022] The application further provides an electrically-controlled hydraulic excavator control method for the above-mentioned electrically-controlled hydraulic excavator, wherein the main control valve corresponding to the boom cylinder is a boom main control valve, one main control pilot end of the boom main control valve is connected with a boom lifting pilot electromagnetic valve, which is used to adjust the state of the boom main control valve to extend the piston rod of the boom cylinder; the main control valve corresponding to the stick cylinder is a stick main control valve, one main control pilot end of the stick main control valve is connected with a stick recovery pilot electromagnetic valve, which is used to adjust the state of the stick main control valve to retract the piston rod of the stick cylinder.

[0023] The electrically-controlled hydraulic excavator has a grading work mode, and the electrically-controlled hydraulic excavator control method comprises the following steps.

[0024] When the electrically-controlled hydraulic excavator performs the grading work mode, the boom demand current is calculated according to the input signal of the boom operation handle, and the stick demand current is calculated according to the input signal of the stick operation handle.

[0025] According to the corresponding relationship between the boom demand current and the working current of the stick recovery pilot electromagnetic valve when the electrically-controlled hydraulic excavator only has the stick action and the stick is recovered, the working current I armin of the stick recovery pilot electromagnetic valve corresponding to the calculated boom demand current is obtained; according to the corresponding relationship between the boom demand current and the working current of the stick recovery pilot electromagnetic valve when the electrically-controlled hydraulic excavator only has the stick and boom actions, the stick is recovered, and the boom is lifted, the working current I bupain of the stick recovery pilot electromagnetic valve corresponding to the calculated boom demand current is obtained; the stick recovery current I armin, I bupain ), the opening of the arm-retraction pilot electromagnetic valve is adjusted according to the arm-retraction current I-ArmIn;

[0026] According to the corresponding relationship between the arm-retraction current and the boom-lifting pilot electromagnetic valve's working current when the electro-controlled excavator only performs the boom operation and the boom is lifted, the boom-lifting pilot electromagnetic valve's working current corresponding to the calculated arm-retraction current is obtained boomup ; According to the corresponding relationship between the arm-retraction current and the boom-lifting pilot electromagnetic valve's working current when the electro-controlled excavator only performs the boom and arm operation and the boom is lifted, the boom-lifting pilot electromagnetic valve's working current corresponding to the calculated arm-retraction current is obtained ainbup ; the boom-lifting current I-BoomUp = min(I boomup , I ainbup ), the opening of the boom-lifting pilot electromagnetic valve is adjusted according to the boom-lifting current I-BoomUp.

[0027] As a preferred technical scheme of the above-mentioned electro-controlled excavator control method, when the boom is lifted and the arm is retracted, or the outlet oil pressure of the variable pump is less than the set pressure, the electro-controlled excavator is controlled to perform the grading work mode.

[0028] As a preferred technical scheme of the above-mentioned electro-controlled excavator control method, the corresponding relationship between the arm-retraction current and the boom-lifting pilot electromagnetic valve's working current when the electro-controlled excavator only performs the boom operation and the boom is lifted is as follows:

[0029] In the formula, i is a positive integer greater than 5, k 11 ~k 1i represents the slope, b 11 ~b 1i represents the intercept, x represents the boom demand current calculated according to the input signal of the arm operation handle, a 11 ~a 1i represents different boom demand currents.

[0030] The corresponding relationship between the arm-retraction current and the boom-lifting pilot electromagnetic valve's working current when the electro-controlled excavator only performs the boom and arm operation and the boom is lifted and the arm is retracted is as follows:

[0031] In the formula, i is a positive integer greater than 5, k 21 ~k 2i represents the slope, b 21 ~b 2i represents the intercept, x represents the boom demand current calculated according to the input signal of the arm operation handle, a 21 ~a 2i represents different boom demand currents.

[0032] The relationship between the current required by the stick and the operating current of the boom lifting pilot solenoid valve in an electrically controlled excavator with only boom movement and boom lifting is as follows:

[0033] In the formula, j is a positive integer greater than 5, and k 31 ~k 3j b represents the slope. 31 ~b 3j The intercept is represented by y, which represents the required current of the stick calculated based on the input signal from the stick control handle, and a is the current required by the stick. 31 ~a 3j This indicates the different current requirements for the boom;

[0034] The relationship between the current demanded by the stick and the operating current of the boom lifting pilot solenoid valve when only the stick and boom of an electrically controlled excavator are moving, with the stick retracted and the boom raised, is as follows:

[0035] In the formula, j is a positive integer greater than 5, and k 41 ~k 4j b represents the slope. 41 ~b 4j The intercept is represented by y, which represents the required current of the stick calculated based on the input signal from the stick control handle, and a is the current required by the stick. 41 ~a 4j This indicates the current required for different booms.

[0036] The beneficial effects of this invention are as follows: The hydraulic control system and electric excavator provided by this invention use a single variable pump, which reduces the number of pumps and lowers costs. By adjusting the working current of each pilot solenoid valve through the electric control handle, the opening degree of the pilot solenoid valve is adjusted, thereby adjusting the extension and retraction of the piston rod of the corresponding working cylinder. At the same time, the displacement of the variable pump is adjusted according to the maximum current value among all pilot solenoid valves, so that the displacement of the variable pump can meet the actual working requirements. Moreover, the response speed is fast, which greatly reduces the manufacturing and operating costs of the excavator.

[0037] The electric excavator leveling control method provided by this invention obtains the relationship between the working currents of the stick retraction pilot solenoid valve and the boom lifting pilot solenoid valve during leveling operations by finding the speed coordination relationship between the stick cylinder and the boom cylinder. Based on the boom demand current and stick demand current, the working current I of the stick retraction pilot solenoid valve is calculated when only the stick moves and the stick is retracted. armin The operating current I of the pilot solenoid valve for the stick retraction pilot solenoid valve is as follows: (1) The electric control excavator only moves the stick and boom, and the stick retracts while the boom is raised. bupain When only the boom moves and the boom is raised in an electrically controlled excavator, the operating current I of the boom lifting pilot solenoid valve is...boomup , and the working current I of the boom lift pilot electromagnetic valve when the arm crowder is retracted and the boom is lifted ainbup ; the boom lift pilot electromagnetic valve is adjusted according to the arm retraction current I-ArmIn = min(I armin , I bupain ), the boom lift pilot electromagnetic valve is adjusted according to the arm retraction current I-ArmIn, the boom lift current I-BoomUp = min(I boomup , I ainbup ), the boom lift pilot electromagnetic valve is adjusted according to the boom lift current I-BoomUp, so that better flat operation is obtained, debugging is simple and fast, the size of the valve core does not need to be frequently changed and the valve core does not need to be replaced, and higher flexibility is obtained, which can be suitable for the operation habits of users. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained according to the contents of the embodiments of the present application and the drawings by those skilled in the art without any creative labor.

[0039] Figure 1 is a schematic diagram of the hydraulic control system of the electrically controlled excavator provided by the embodiments of the present application;

[0040] Figure 2 is a connection relationship diagram between the boom main control valve, the boom cylinder, the boom pressure compensation valve and the boom cartridge valve when the boom main control valve is in the boom lifting working position in the hydraulic control system of the electrically controlled excavator provided by the embodiments of the present application;

[0041] Figure 3 is a connection relationship diagram between the boom main control valve, the boom cylinder, the boom pressure compensation valve and the boom cartridge valve when the boom main control valve is in the boom lowering working position in the hydraulic control system of the electrically controlled excavator provided by the embodiments of the present application;

[0042] Figure 4 is a flow chart of the control method of the electrically controlled excavator provided by the embodiments of the present application.

[0043] In the drawings:

[0044] 1, variable pump;

[0045] 21, boom cylinder; 22, boom main control valve; 221, boom oil inlet; 222, boom oil return; 223, first boom compensation oil port; 224, first boom working oil port; 225, second boom working oil port; 226, second boom compensation oil port; 227, third boom compensation oil port; 228, fourth boom compensation oil port;

[0046] 23, boom pressure compensation valve; 231, boom compensation oil inlet; 232, boom compensation oil return; 233, boom pressure compensation oil port; 24, boom cartridge valve; 241, first boom cartridge working oil port; 242, second boom cartridge working oil port; 25, boom lifting pilot solenoid valve; 26, boom lowering pilot solenoid valve;

[0047] 31, arm cylinder; 32, arm main control valve; 33, arm pressure compensation valve; 34, arm cartridge valve; 35, arm recovery pilot solenoid valve; 36, arm opening pilot solenoid valve;

[0048] 41, bucket cylinder; 42, bucket main control valve; 43, bucket pressure compensation valve;

[0049] 5, swing motor;

[0050] 6, compensation throttle valve;

[0051] 7, operation unit;

[0052] 8, excavator controller;

[0053] 100, first pressure compensation oil path; 200, second pressure compensation oil path. DETAILED DESCRIPTION

[0054] The present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the present application and not in limitation thereof. It should also be noted that, for the purpose of description, only the parts related to the present application are shown in the drawings and not all the parts.

[0055] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "linked", "fixed" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0056] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature is "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0057] In the description of the present embodiment, the terms "upper", "lower", "right", "left", and other orientation or position relationships are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in description and have no special meaning.

[0058] As shown in Figures 1 to 3 The present embodiment provides an electrically controlled excavator hydraulic control system, which comprises a variable pump 1, a plurality of working components, a plurality of main control valves and a plurality of pressure compensation valves corresponding to the plurality of working components one by one, the variable pump 1 can control the piston rod of the corresponding working component to extend or retract through the main control valve; the plurality of working components comprises two working oil cylinders, which are respectively a boom cylinder 21 and a stick cylinder 31.

[0059] The main control valve has two main control pilot ends, and the electrically controlled excavator hydraulic control system further comprises a pilot oil way and a pilot electromagnetic valve corresponding to the main control pilot end one by one, wherein each main control pilot end is in communication with one end of the corresponding pilot oil way, and the other end is in communication with other pilot oil ways. The pilot electromagnetic valve is arranged on the corresponding pilot oil way, and the opening degree of the pilot electromagnetic valve is adjustable; the pilot electromagnetic valve has an electromagnetic pilot end and a hydraulic control pilot end, and the hydraulic control pilot end of the pilot electromagnetic valve is in communication with the corresponding main control pilot end.

[0060] The electrically controlled excavator hydraulic control system further comprises an electric control handle, each electromagnetic pilot end is electrically connected with the electric control handle, and the electric control handle is used for controlling the working current of each pilot electromagnetic valve to adjust the opening degree of the pilot electromagnetic valve; the electric control handle is electrically connected with the variable pump 1, and is used for adjusting the displacement of the variable pump 1 according to the maximum current value in the working current of all pilot electromagnetic valves.

[0061] The hydraulic control system of the electrically-controlled excavator provided by the embodiment adopts a single variable pump 1, reduces the number of pumps, and lowers the cost; the working current of each pilot electromagnetic valve is adjusted by the electrically-controlled handle to adjust the opening of the pilot electromagnetic valve, thereby adjusting the extension and retraction of the piston rod of the corresponding working oil cylinder, and the displacement of the variable pump 1 is adjusted according to the maximum current value in the working currents of all the pilot electromagnetic valves, so that the displacement of the variable pump 1 can meet the actual working demand.

[0062] Further, each working component is respectively provided with a pressure compensation valve, and the first compensation pilot end of each pressure compensation valve is communicated to form a first pressure compensation oil path 100, and the first compensation pilot end is provided with a pressure compensation reset spring. The main control valve has a main control working position, when the main control valve is in the main control working position, the oil outlet of the variable pump 1 is communicated with the second compensation pilot end of the pressure compensation valve through the main control valve, and the oil inlet of the working component is communicated with the oil tank through the main control valve and the pressure compensation valve to form an oil inlet channel, and the oil outlet of the working component is communicated with the oil tank through the main control valve to form an oil return channel.

[0063] The pressure compensation valve has a pressure compensation left position, a pressure compensation middle position and a pressure compensation right position, when the pressure compensation valve is in the pressure compensation left position, the oil inlet channel is communicated and the oil inlet channel can be communicated with the first compensation pilot end of the pressure compensation valve through the throttle hole on the valve core of the pressure compensation valve; when the pressure compensation valve is in the pressure compensation middle position, the oil inlet channel flows through the compensation throttle hole; when the pressure compensation valve is in the pressure compensation right position, the oil inlet channel is disconnected.

[0064] When the electrically-controlled excavator is not working, the pressure compensation valve is in the pressure compensation right position under the action of the pressure compensation reset spring. When the main control valve is in the working position, the working oil of the variable pump 1 is sent to the second compensation pilot end of the pressure compensation valve through the main control valve, so that the valve core of the pressure compensation valve is actuated, the pressure compensation valve is quickly switched to the pressure compensation left position, so that the oil inlet channel is communicated to realize the quick oil supply to the working component; at the same time, a small amount of pressure oil in the oil inlet channel is sent to the first compensation pilot end through the throttle hole on the valve core of the pressure compensation valve, so that the pressure difference between the first compensation pilot end and the second compensation pilot end gradually decreases, the pressure compensation valve starts to switch to the pressure compensation middle position, and after the pressure compensation valve switches to the pressure compensation middle position, the oil inlet channel flows through the compensation throttle hole to realize the slow oil supply to the working component. Then the pressure compensation valve will gradually switch to the pressure compensation middle position, and when the pressure compensation valve switches to the pressure compensation middle position, the oil inlet channel is disconnected to stop the oil supply to the working component.

[0065] Since the first compensation pilot port of each pressure compensation valve is communicated to form the first pressure compensation oil path 100, during the process that the main control valve is in the working position and the working components are quickly supplied with oil through the main control valve and the pressure compensation valve, the pressure oil sent to the corresponding first compensation pilot port enters the first compensation pilot port of the other pressure compensation valve through the first pressure compensation oil path 100, so that the coupling control between the pressure compensation valves is realized.

[0066] Further, each working oil cylinder is respectively provided with a cartridge valve, and the cartridge valve has two cartridge working oil ports, one of which is communicated with the rod cavity of the corresponding working oil cylinder, and the other of which can be selectively communicated with the tank or the rodless cavity of the corresponding working oil cylinder through the corresponding main control valve when the main control valve is in the main control working position; the spring cavity of each cartridge valve can be communicated through the corresponding main control valve to form the second pressure compensation oil path 200, and the first pressure compensation oil path 100 is communicated with the second pressure compensation oil path 200 through the compensation throttle valve 6.

[0067] When the main control valve is in the main control working position, the cartridge valve cooperates with the main control valve and the pressure compensation valve to make the variable pump 1 provide the pressure oil to enter and exit the working oil cylinder, and when the main control valve is in the main control working position, the piston rod of the working oil cylinder is extended, and the pressure compensation valve is in the pressure compensation left position, the pressure oil of the first compensation pilot port enters the first pressure compensation oil path 100; during the process that the pressure oil in the rod cavity of the working oil cylinder returns to the tank through the cartridge valve and the main control valve, the pressure oil in the spring cavity of the cartridge valve enters the second pressure compensation oil path 200 through the main control valve; since the first compensation oil path is communicated with the second pressure compensation oil path 200 through the compensation throttle valve 6, the first compensation pilot port of the pressure compensation valve can be communicated with the spring cavity of the cartridge valve through the compensation throttle valve 6, the fast pressure compensation valve can be quickly switched to the pressure compensation middle position, and the cartridge valve can be quickly closed.

[0068] The main control valve, the pressure compensation valve and the cartridge valve corresponding to the boom oil cylinder 21 are the boom main control valve 22, the boom pressure compensation valve 23 and the boom cartridge valve 24 respectively, and the main control valve, the pressure compensation valve and the cartridge valve corresponding to the stick main control valve 32 are the stick main control valve 32, the stick pressure compensation valve 33 and the stick cartridge valve 34 respectively.

[0069] The boom pressure compensation valve 23 and the stick pressure compensation valve 33 are the same in structure, the boom cartridge valve 24 and the stick cartridge valve 34 are the same in structure, and the connection relationship between the boom cylinder 21 and the corresponding main control valve, pressure compensation valve and cartridge valve is the same as that between the stick cylinder 31 and the corresponding main control valve, pressure compensation valve and cartridge valve. Hereinafter, the connection relationship between the boom cylinder 21 and the boom main control valve 22, boom pressure compensation valve 23 and cartridge valve will be briefly introduced by taking the boom cylinder 21 as an example.

[0070] For the convenience of description, the main control valve corresponding to the boom cylinder 21 is denoted as the boom main control valve 22, and the two pilot electromagnetic valves connected to the two main control pilot ends of the boom main control valve 22 are denoted as the boom lifting pilot electromagnetic valve 25 and the boom lowering pilot electromagnetic valve 26, respectively. The boom lifting pilot electromagnetic valve 25 is used to adjust the working current of the boom main control valve 22 to make the piston rod of the boom cylinder 21 extend, thereby realizing boom lifting. The boom lowering pilot electromagnetic valve 26 is used to adjust the working current of the boom main control valve 22 to make the piston rod of the boom cylinder 21 retract, thereby realizing boom lowering.

[0071] The boom lifting pilot electromagnetic valve 25, boom lowering pilot electromagnetic valve 26 and variable pump 1 are electrically connected to the excavator controller 8. The working current of the boom lifting pilot electromagnetic valve 25 and the boom lowering pilot electromagnetic valve 26 is adjusted by the excavator controller 8 to realize the state adjustment of the boom main control valve 22.

[0072] The pressure compensation valve corresponding to the boom main control valve 22 is the boom pressure compensation valve 23, and the cartridge valve corresponding to the boom main control valve 22 is the boom cartridge valve 24. The boom main control valve 22 has two working positions and a neutral position. The two working positions are denoted as the boom lifting position and the boom lowering position, respectively, and the neutral position of the boom main control valve 22 is denoted as the boom neutral position.

[0073] The boom main control valve 22 has two boom return ports 222, a boom inlet port 221, a first boom compensation port 223, a first working oil port, a second working oil port, a second boom compensation port 226, a third boom compensation port 227 and a fourth boom compensation port 228. The two boom return ports 222 are in communication with the oil tank, the boom inlet port 221 is in communication with the oil outlet of the variable pump 1, the second boom working oil port 225 is in communication with the rodless chamber of the boom cylinder 21, and the fourth boom compensation port 228 is in communication with the spring chamber of the boom cartridge valve 24.

[0074] The two insertion work oil ports of the boom insertion type hydraulic control valve 24 are respectively marked as a first boom insertion work oil port 241 and a second boom insertion work oil port 242. The first boom insertion work oil port 241 is in communication with the rod cavity of the boom cylinder 21. The second boom insertion work oil port 242 is in communication with the first boom work oil port 224. The second boom insertion work oil port 242 is located at the axial two ends of the spool of the boom insertion type hydraulic control valve 24. The second boom insertion work oil port 242 can selectively communicate with or disconnect from the first boom insertion work oil port 241.

[0075] The boom pressure compensation valve 23 is a hydraulic control valve. The two compensation pilot ports of the boom pressure compensation valve 23 are respectively marked as a second compensation pilot port and a first compensation pilot port. The boom pressure compensation valve 23 has a boom compensation inlet port 231, a boom compensation outlet port 232 and a boom pressure compensation oil port 233. The second boom compensation oil port 226 is in communication with the second compensation pilot port and the boom compensation inlet port 231. The boom compensation outlet port 232 is in communication with the third boom compensation oil port 227. The boom pressure compensation oil port 233 is in communication with the first compensation pilot port. The first compensation pilot port is in communication with the first boom compensation oil port 223.

[0076] When the boom main control valve 22 is in the boom lifting working position, the boom inlet port 221 is in communication with the second boom compensation oil port 226. The first boom work oil port 224 is in communication with the boom return oil port 222 through the throttle hole on the spool of the boom main control valve 22. The first boom work oil port 224 can be in communication with the second boom work oil port 225 through the check valve. The third boom compensation oil port 227 is in communication with the second boom work oil port 225. The fourth boom compensation oil port 228 is in communication with the first boom compensation oil port 223.

[0077] When the boom main control valve 22 is in the boom lowering working position, the boom inlet port 221 is in communication with the second boom compensation oil port 226. The third boom compensation oil port 227 is in communication with the first boom work oil port 224. The second boom work oil port 225 is in communication with the boom return oil port 222. The fourth boom compensation oil port 228 and the first boom compensation oil port 223 are both blocked by the spool of the boom main control valve 22.

[0078] When the boom main control valve 22 is in the boom neutral position, all the oil ports of the boom main control valve 22 are blocked by the spool of the boom main control valve 22.

[0079] The boom pressure compensation valve 23 has three positions: left-hand boom pressure compensation, center-hand boom pressure compensation, and right-hand boom pressure compensation. When the boom pressure compensation valve 23 is in the left-hand position, the boom compensation inlet 231 is connected to the boom compensation outlet 232, and the inlet 231 is connected to the boom pressure compensation outlet 233 through a throttling orifice on the valve core. When the boom pressure compensation valve 23 is in the center-hand position, the inlet 231 is connected to the outlet 232 through a throttling orifice on the valve core, and the outlet 232 is blocked. When the boom pressure compensation valve 23 is in the right-hand position, all three positions—inlet 231, outlet 232, and outlet 233—are blocked.

[0080] The working process of boom cylinder 21 will be briefly described below with reference to the attached drawings.

[0081] like Figure 1 and Figure 2 As shown, during boom lifting: the boom main control valve 22 is in the boom lifting working position. The pressure oil supplied by the variable pump 1 enters the second compensation pilot end of the boom pressure compensation valve 23 through the boom main control valve 22. When the oil pressure at the second compensation pilot end is greater than the oil pressure at the first compensation pilot end, the valve core of the boom pressure compensation valve 23 actuates, and the boom pressure compensation valve 23 is switched to the boom pressure compensation left position. The pressure oil flowing out of the boom pressure compensation valve 23 flows out through the third boom compensation oil port 227 and the second boom working oil port 225 into the rodless chamber of the boom cylinder 21; simultaneously, the boom... The pressurized oil in the rod chamber of the hydraulic cylinder 21 enters the boom pressure compensation valve 23 through the first boom cartridge working port 241, connecting the first boom cartridge working port 241 and the second boom cartridge working port 242. The pressurized oil flowing out of the second boom cartridge working port 242 returns to the second boom working port 225 through the first boom working port 224 and the check valve in the boom main control valve 22. A small amount of pressurized oil may return to the oil tank through the first boom working port 224, the throttle orifice on the valve core of the boom main control valve 22, and the boom return port 222. At the same time, the pressurized oil in the spring chamber of the boom cartridge hydraulic control valve 24 enters the second pressure compensation oil circuit 200 through the fourth boom compensation oil port 228 and the first boom compensation oil port 223. Also, due to the movement of the valve core of the boom pressure compensation valve 23, the pressurized oil at the first compensation pilot end enters the first pressure compensation oil circuit 100. When the oil pressure in the first pressure compensation oil circuit 100 is different from the oil pressure in the second pressure compensation oil circuit 200, the pressure will overflow from high pressure to low pressure, thereby actuating the valve core of the boom pressure compensation valve 23 and the valve core of the boom cartridge hydraulic control valve 24 to achieve pressure compensation.

[0082] When the boom is lifted, the pressure oil in the rod cavity of the boom cylinder 21 can be returned to the rodless cavity of the boom cylinder 21 through the boom cartridge valve 24, so that the pressure oil is recycled, the extension speed of the piston rod of the boom cylinder 21 is improved, and the lifting speed of the boom is improved.

[0083] As shown in Figure 1 and Figure 3 , the boom is lowered: the boom main control valve 22 is in the boom lowering working position, the pressure oil provided by the variable pump 1 enters the second compensation pilot end of the boom pressure compensation valve 23 through the boom main control valve 22, when the oil pressure at the second compensation pilot end is greater than the oil pressure at the first compensation pilot end, the valve core of the boom pressure compensation valve 23 acts, the boom pressure compensation valve 23 is switched to the boom pressure compensation left position, and the pressure oil flowing out of the boom pressure compensation valve 23 enters the boom cartridge valve 24 through the third boom compensation oil port 227, the first boom working oil port 224 and the second boom cartridge working oil port 242. When the second boom cartridge working oil port 242 and the first boom cartridge working oil port 241 are communicated, the pressure oil enters the rod cavity of the boom cylinder 21 through the first boom cartridge working oil port 241; at the same time, the pressure oil in the rodless cavity of the boom cylinder 21 returns to the oil tank through the second boom working oil port 225 and the boom oil return port 222.

[0084] For the convenience of description, the main control valve corresponding to the arm cylinder 31 is referred to as the arm main control valve 32, and the two pilot electromagnetic valves connected to the two main control pilot ends of the arm main control valve 32 are referred to as the arm recovery pilot electromagnetic valve 35 and the arm opening pilot electromagnetic valve 36, respectively. Among them, the arm recovery pilot electromagnetic valve 35 is used to adjust the working current of the arm main control valve 32 to make the piston rod of the arm cylinder 31 retract, so as to realize the arm recovery; the arm opening pilot electromagnetic valve 36 is used to adjust the working current of the arm main control valve 32 to make the piston rod of the arm cylinder 31 extend, so as to realize the arm opening.

[0085] The arm recovery pilot electromagnetic valve 35 and the arm opening pilot electromagnetic valve 36 are electrically connected to the excavator controller 8, and the working currents of the arm recovery pilot electromagnetic valve 35 and the arm opening pilot electromagnetic valve 36 are adjusted through the excavator controller 8 to realize the state adjustment of the arm main control valve 32.

[0086] The pressure compensation valve corresponding to the arm main control valve 32 is the arm pressure compensation valve 33, and the cartridge valve corresponding to the arm main control valve 32 is the arm cartridge valve 34.

[0087] The structure of the boom pressure compensation valve 23 is the same as that of the arm pressure compensation valve 33, the structure of the boom plug-in hydraulic control valve 24 is the same as that of the arm plug-in hydraulic control valve 34, the connection relationship between the boom pressure compensation valve 33, the boom plug-in hydraulic control valve 34, the boom cylinder 31 and the boom main control valve 32 is the same as that of the relevant components of the arm, and only the structure of the boom main control valve 32 is slightly different from that of the arm main control valve 22. The boom main control valve 32 is not provided with a throttle hole and a one-way valve inside.

[0088] Further, a throttle valve is arranged on the connection oil passage between the pressure compensation oil passage and the main control valve. In this way, the association between the boom pressure compensation valve 23, the boom plug-in hydraulic control valve 24, the arm pressure compensation valve 33 and the arm plug-in hydraulic control valve 34 is ensured, and the flow distribution and pressure compensation adjustment during the combined operation of the boom and the arm are realized.

[0089] Further, the plurality of working components further include a bucket cylinder 41, a traveling motor and a slewing motor 5, each of which is provided with a main control valve and a pressure compensation valve in a one-to-one correspondence. The connection relationship between each valve and the corresponding working component is substantially the same as the connection relationship between the working cylinder and the corresponding valve, and the only difference is that no plug-in hydraulic control valve is arranged. Hereinafter, the connection relationship between the relevant components of the bucket cylinder 41 will be introduced by taking the bucket cylinder 41 as an example.

[0090] The main control valve and the pressure compensation valve corresponding to the bucket cylinder 41 are a bucket main control valve 42 and a bucket pressure compensation valve 43, respectively. The first compensation pilot end of the bucket pressure compensation valve 43 is in communication with the first pressure compensation oil passage 100, thereby realizing the association of each pressure compensation valve. The bucket main control valve 42 has a bucket recovery position, a bucket opening position and a bucket neutral position. When the bucket main control valve 42 is in the bucket neutral position, the two oil chambers of the bucket cylinder 41 are disconnected from the variable pump 1 and the oil tank, and the two oil chambers of the bucket cylinder 41 are not in communication with each other.

[0091] When the bucket main control valve 42 is in the bucket recovery position, the pressure oil provided by the variable pump 1 enters the rodless chamber of the bucket cylinder 41 through the bucket main control valve 42 and the bucket pressure compensation valve 43, and at the same time, the pressure oil in the rod chamber of the bucket cylinder 41 returns to the oil tank through the bucket main control valve 42.

[0092] When the bucket main control valve 42 is in the bucket opening position, the pressure oil provided by the variable pump 1 enters the rod chamber of the bucket cylinder 41 through the bucket main control valve 42 and the bucket pressure compensation valve 43, and at the same time, the pressure oil in the rodless chamber of the bucket cylinder 41 returns to the oil tank through the bucket main control valve 42.

[0093] Further, each oil inlet passage and each oil return passage can be in communication with the oil tank through an overflow valve, respectively. The overflow valve is arranged to provide high-pressure protection.

[0094] Furthermore, a pressure sensor is provided at the oil outlet of the variable pump 1 to detect the outlet oil pressure of the variable pump 1 in order to determine whether the displacement of the variable pump 1 meets the requirements.

[0095] This embodiment also provides an electrically controlled excavator, employing the aforementioned hydraulic control system and an operating unit 7. The operating unit 7 is electrically connected to the pilot solenoid valve of each main control valve. The operating unit 7 includes an electric control handle and is used to adjust the operating current of each pilot solenoid valve. In other embodiments, the operating unit 7 may also be an electric control foot handle.

[0096] The electric control handle and pilot solenoid valve are both electrically connected to the excavator controller 8. The electric control handle includes a boom control handle for controlling boom lifting and boom lowering, and a stick control handle for controlling stick opening and stick retraction. The operator can control the boom and bucket movements by operating the corresponding control handles.

[0097] like Figure 4 As shown, this embodiment also provides a control method for an electric excavator, used in the aforementioned electric excavator; the electric excavator has a leveling work mode, and the control method for the electric excavator includes the following steps:

[0098] The electrically controlled excavator has a leveling mode, and the control method for the electrically controlled excavator includes the following steps:

[0099] S1. When the electric excavator is in leveling mode, calculate the boom current demand based on the input signal of the boom control handle and the stick current demand based on the input signal of the stick control handle; execute S2 and S3 simultaneously.

[0100] S2. Based on the correspondence between the boom current demand and the operating current of the boom retraction pilot solenoid valve 35 when the electric control excavator only moves the boom and retracts the boom, obtain the operating current I of the boom retraction pilot solenoid valve 35 corresponding to the calculated boom current demand. armin Based on the correspondence between the boom current demand and the operating current of the boom retraction pilot solenoid valve 35 when only the stick and boom of the electric excavator are moving, and the stick is retracted and the boom is raised, the operating current I of the boom retraction pilot solenoid valve 35 corresponding to the calculated boom current demand is obtained. bupain ; The boom recovery current I-ArmI n=mi n(I armin I bupain Adjust the opening of the boom recovery pilot solenoid valve 35 according to the boom recovery current I-ArmI n;

[0101] S3, according to the corresponding relationship between the boom-up pilot solenoid 25 current and the bucket demand current when the electrically controlled excavator only boom and bucket are operated and the bucket is retracted and the boom is lifted, the boom-up pilot solenoid 25 current corresponding to the calculated bucket demand current is obtained boomup ; according to the corresponding relationship between the boom-up pilot solenoid 25 current and the bucket demand current when the electrically controlled excavator only boom and bucket are operated and the bucket is retracted and the boom is lifted, the boom-up pilot solenoid 25 current corresponding to the calculated bucket demand current is obtained ainbup ; the boom-up current I-BoomUp = min(I boomup , I ainbup ), the boom-up pilot solenoid 25 opening is adjusted according to the boom-up current I-BoomUp.

[0102] The control method of the electrically controlled excavator provided by the embodiment obtains the corresponding relationship between the bucket retraction pilot solenoid 35 current and the boom-up pilot solenoid 25 current when the bucket is retracted during the grading operation through the matching relationship between the piston rod extension and retraction speed of the bucket cylinder 31 and the piston rod extension and retraction speed of the boom cylinder 21, adjusts the opening of the bucket main control valve 32 according to the bucket retraction pilot solenoid 35 current, adjusts the opening of the boom main control valve 22 according to the boom-up pilot solenoid 25 current, and adjusts the opening of the bucket retraction pilot solenoid 35 and the boom-up pilot solenoid 25 according to the boom demand current and the bucket demand current through the relationship, so that better grading operability is obtained, the debugging is simple and fast, the size of the spool and the spool need not be frequently changed, the flexibility is higher, and the control method can be adapted to the operation habits of users.

[0103] In the embodiment, the bucket retraction pilot solenoid 35 current is a piecewise function relationship when the electrically controlled excavator only bucket is operated and the bucket is retracted, and the specific relationship is as follows:

[0104] In the formula, i is a positive integer greater than 5, k 11 ~k 1i represents the slope, b 11 ~b 1i represents the intercept, x represents the boom demand current calculated according to the input signal of the operation handle, a 11 ~a 1i represents different boom demand currents.

[0105] In the embodiment, the bucket retraction pilot solenoid 35 current is a piecewise function relationship when the electrically controlled excavator only bucket and boom are operated and the bucket is retracted and the boom is lifted, and the specific relationship is as follows:

[0106] In the formula, i is a positive integer greater than 5, k 11 ~k 1i represents the slope, b 11 ~b 1i represents the intercept, x represents the boom demand current calculated according to the input signal of the operation handle, a 11 ~a 1i represents different boom demand currents.21 ~k 2i denotes the slope, b 21 ~b 2i denotes the intercept, x denotes the boom demand current calculated according to the input signal of the boom operating handle, a 21 ~a 2i denotes different boom demand currents.

[0107] In this embodiment, the working current of the boom-raising pilot electromagnetic valve 25 of the electric-controlled excavator is a piecewise function when the boom is operated and the boom is raised, and is specifically as follows:

[0108] In the formula, j is a positive integer greater than 5, k 31 ~k 3j denotes the slope, b 31 ~b 3j denotes the intercept, y denotes the arm demand current calculated according to the input signal of the arm operating handle, a 31 ~a 3j denotes different arm demand currents.

[0109] In this embodiment, the working current of the boom-raising pilot electromagnetic valve 25 of the electric-controlled excavator is a piecewise function when the boom and the arm are operated, the arm is retracted, and the boom is raised, and is specifically as follows:

[0110] In the formula, j is a positive integer greater than 5, k 41 ~k 4j denotes the slope, b 41 ~b 4j denotes the intercept, y denotes the arm demand current calculated according to the input signal of the arm operating handle, a 41 ~a 4j denotes different arm demand currents.

[0111] Further, when the boom is raised and the arm is retracted, or the outlet oil pressure of the variable pump 1 is less than the set pressure, the electric-controlled excavator is controlled to perform the grading work mode. The set pressure is a known value set according to the actual demand.

[0112] The hydraulic control system of the electric-controlled excavator provided in this embodiment adopts a variable pump 1, monitors the actual work demand of the electric-controlled excavator in real time, obtains the actual demand current of the variable pump 1 according to the actual work demand of the electric-controlled excavator, adjusts the displacement of the variable pump 1 according to the actual demand current, adjusts the working current of each main control valve when the boom and the arm are operated according to each main control valve cooperating with the corresponding pressure compensation valve, thereby realizing flow distribution and ensuring the coordination and softness when both working oil cylinders are operated.

[0113] The variable pump 1 is used as the main pump, the number of main pumps and the number of action correlations between the main pumps and corresponding main control valves are reduced, the cost is reduced, the structure is simplified, the hydraulic control system of the electric control excavator is facilitated to be arranged, the arrangement space of the hydraulic control system of the electric control excavator is saved, the displacement adjustment of the variable pump 1 is realized through the cooperation of the pressure compensation valve and the main control valve, and the logic algorithm of the displacement adjustment of the variable pump 1 is simplified.

[0114] In terms of performance, the response speed of the variable pump 1 is improved while the operability is ensured, the operability and energy saving are high, and the operation habits of different users can be applied; in terms of function, when the flat operation is debugged, the flat operation can be more flexibly debugged to match the flat action, so that better flat operation is obtained, and the valve core size does not need to be frequently changed and the valve core does not need to be frequently replaced.

[0115] In addition, the above are only preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. An electrically controlled hydraulic control system for a backhoe, comprising a variable pump (1), a plurality of working components, and a plurality of main control valves corresponding to the plurality of working components one by one, the variable pump (1) being capable of controlling the extension and retraction of the piston rod of the corresponding working component through the main control valve; the plurality of working components comprising two working oil cylinders, namely a boom cylinder (21) and a stick cylinder (31); the main control valve having two main control pilot ends, characterized in that, Also include: Pilot oil circuit, one-to-one correspondence with the master control pilot end, each of the master control pilot end is respectively communicated with the corresponding pilot oil circuit one end, the other end and other pilot oil circuit convergence communication; Pilot solenoid valve, one-to-one correspondence with the master control pilot end and set in the corresponding pilot oil circuit, the opening of the pilot solenoid valve can be adjusted; the pilot solenoid valve has electromagnetic pilot end and hydraulic control pilot end, the hydraulic control pilot end of the pilot solenoid valve is communicated with the corresponding master control pilot end; Operation part (7), each of the electromagnetic pilot end is electrically connected with the operation part (7), the operation part (7) is used for controlling the working current of each of the pilot solenoid valve to adjust the opening of the pilot solenoid valve; the operation part (7) is electrically connected with the variable pump (1), used for adjusting the displacement of the variable pump (1) according to the maximum current value in all the working current of the pilot solenoid valve; each of the working parts is respectively corresponding to one pressure compensation valve, the first compensation pilot end of each of the pressure compensation valve is communicated to form a first pressure compensation oil circuit (100), the first compensation pilot end is provided with a pressure compensation reset spring; The master control valve has a master control working position, when the master control valve is in the master control working position, the oil outlet of the variable pump (1) is communicated with the second compensation pilot end of the pressure compensation valve through the master control valve, and the oil outlet of the variable pump (1) can be communicated with the oil inlet of the working part through the master control valve and the pressure compensation valve to form an oil inlet channel, and the oil outlet of the working part is communicated with the oil tank through the master control valve to form an oil return channel; The pressure compensation valve has a pressure compensation left position, a pressure compensation middle position and a pressure compensation right position, when the pressure compensation valve is in the pressure compensation left position, the oil inlet channel is communicated and the oil inlet channel can be communicated with the first compensation pilot end of the pressure compensation valve through the compensation orifice on the valve core of the pressure compensation valve; when the pressure compensation valve is in the pressure compensation middle position, the oil inlet channel flows through the compensation orifice; when the pressure compensation valve is in the pressure compensation right position, the oil inlet channel is disconnected.

2. The electrically controlled hydraulic control system of the excavator according to claim 1, wherein the plurality of working parts further comprise a bucket cylinder (41), a traveling motor and a swing motor (5).

3. The electrically controlled hydraulic control system of the excavator according to claim 2, wherein each of the working cylinders is respectively corresponding to one cartridge valve; The cartridge valve has two cartridge working oil ports, one of which is communicated with the rod cavity of the corresponding working cylinder, and the other of which can be selectively communicated with the oil tank or the rodless cavity of the corresponding working cylinder through the corresponding master control valve when the master control valve is in the master control working position; The spring cavity of each of the cartridge valves can be communicated with the second pressure compensation oil circuit (200) through the corresponding master control valve, and the first pressure compensation oil circuit (100) is communicated with the second pressure compensation oil circuit (200) through a compensation orifice (6).

4. The electrically controlled hydraulic excavator control system according to claim 3, characterized by, The spool of the plug-in hydraulic control valve is provided with a throttle hole, and the rod cavity of the working oil cylinder is communicated with the spring cavity of the plug-in hydraulic control valve through the throttle hole.

5. The electrically controlled hydraulic excavator control system of claim 1, wherein, The main control valve corresponding to the boom cylinder (21) is a boom main control valve (22), a boom throttle hole is arranged on the spool of the boom main control valve (22), and a boom check valve is integrated in the boom main control valve (22). When the boom main control valve (22) is in the main control working position and the piston rod of the boom cylinder (21) is extended, the rod cavity of the boom cylinder (21) can be communicated with the oil tank through the boom throttle hole and is unidirectionally communicated with the rodless cavity of the boom cylinder (21) through the boom check valve.

6. An electrically controlled excavator characterized by The electrically controlled excavator hydraulic control system comprises the electrically controlled excavator hydraulic control system according to any one of claims 1 to 5.

7. An electrically controlled excavator control method, characterized by, The electrically controlled excavator corresponding to claim 6, the main control valve corresponding to the boom cylinder (21) is a boom main control valve (22), one main control pilot end of the boom main control valve (22) is connected with a boom lifting pilot electromagnetic valve (25) for adjusting the state of the boom main control valve (22) to make the piston rod of the boom cylinder (21) extend, and the main control valve corresponding to the stick cylinder (31) is a stick main control valve (32), one main control pilot end of the stick main control valve (32) is connected with a stick recovery pilot electromagnetic valve (35) for adjusting the state of the stick main control valve (32) to make the piston rod of the stick cylinder (31) retract. The electrically controlled excavator has a grading work mode, and the electrically controlled excavator control method comprises the following steps: When the electrically controlled excavator executes the grading work mode, the boom demand current is calculated according to the input signal of the boom operation handle, and the stick demand current is calculated according to the input signal of the stick operation handle. According to the corresponding relationship between the demand current of the boom and the working current of the bucket rod recovery pilot solenoid valve (35) when the electric control excavator only acts on the bucket rod and the boom is raised, the working current I of the bucket rod recovery pilot solenoid valve (35) corresponding to the calculated demand current of the boom is obtained armin ; According to the corresponding relationship between the demand current of the boom and the working current of the bucket rod recovery pilot solenoid valve (35) when the electric control excavator only acts on the bucket rod and the boom is raised, the working current I of the bucket rod recovery pilot solenoid valve (35) corresponding to the calculated demand current of the boom is obtained bupain ; The bucket rod recovery current I-ArmIn=min(I armin , I bupain ), the opening of the bucket rod recovery pilot solenoid valve (35) is adjusted according to the bucket rod recovery current I-ArmIn. According to the corresponding relationship between the boom lifting pilot solenoid valve (25) working current corresponding to the bucket rod demand current and the calculated bucket rod demand current of the electric control excavator only boom action and boom lifting, the boom lifting pilot solenoid valve (25) working current I boomup corresponding to the calculated bucket rod demand current is obtained according to the corresponding relationship between the boom lifting pilot solenoid valve (25) working current and the bucket rod demand current when the electric control excavator only bucket rod and boom action and the bucket rod is recovered and the boom is lifted. ainbup ; The boom lifting current I-BoomUp=min(I boomup , I ainbup ) is obtained according to the corresponding relationship between the boom lifting pilot solenoid valve (25) working current and the bucket rod demand current when the electric control excavator only boom action and boom lifting, and the boom lifting pilot solenoid valve (25) opening is adjusted according to the boom lifting current I-BoomUp.

8. The electrically controlled excavator control method according to claim 7, characterized by, Further comprising: When the boom is lifted and the stick is retracted, or the outlet oil pressure of the variable pump (1) is less than the set pressure, the electrically controlled excavator is controlled to execute the grading work mode.

9. The electrically controlled excavator control method according to claim 7, characterized by, The corresponding relationship between the stick demand current and the working current of the stick recovery pilot electromagnetic valve (35) when the electrically controlled excavator only has the stick action and the stick is retracted is as follows: ; where i is a positive integer greater than 5, k 11 k 1i represents a slope, b 11 b 1i represents an intercept, x represents a demand current of the boom calculated from an input signal of the operation handle, a 11 a 1i represents different demand currents of the boom; The corresponding relationship between the stick demand current and the working current of the stick recovery pilot electromagnetic valve (35) when the electrically controlled excavator only has the stick and boom actions, the stick is retracted, and the boom is lifted is as follows: ; where i is a positive integer greater than 5, k 21 k 2i represents a slope, b 21 b 2i represents an intercept, x represents a demand current of the boom calculated from an input signal of a boom operation handle, a 21 a 2i represents a different demand current of the boom; The corresponding relationship between the stick demand current and the working current of the boom lifting pilot electromagnetic valve (25) when the electrically controlled excavator only has the boom action and the boom is lifted is as follows: ; where j is a positive integer greater than 5, k 31 k 3j represents a slope, b 31 b 3j represents an intercept, y represents a boom demand current calculated from an input signal of a boom operation handle, a 31 a 3j represents different boom demand currents; The corresponding relationship between the stick demand current and the working current of the boom lifting pilot electromagnetic valve (25) when the electrically controlled excavator only has the stick and boom actions, the stick is retracted, and the boom is lifted is as follows: ; where j is a positive integer greater than 5, k 41 k 4j represents a slope, b 41 b 4j represents an intercept, y represents a boom demand current calculated from an input signal of a boom operation handle, a 41 a 4j represents different boom demand currents.

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