An electric loader hydraulic system and electric loader

Abstract

The application discloses an electric loader hydraulic system and an electric loader. In the system, a working pump drives a boom cylinder and a bucket cylinder through a distribution valve, a steering pump drives a steering cylinder through a flow amplification valve, and an oil port PF of the flow amplification valve is connected with an outlet of the working pump. An outlet of a pilot oil source valve is connected with an inlet of a steering gear. A controller collects pilot pressures of each control port of the distribution valve, an outlet pressure of the working pump, a rotation angular velocity of the steering gear, and matches a displacement of the working pump with a rotation speed of a working pump hydraulic motor, matches a handle opening degree with the displacement of the working pump and the rotation speed of the working pump hydraulic motor, and matches the rotation angular velocity of the steering gear with a displacement of the steering pump and a rotation speed of a steering pump hydraulic motor, so as to realize positive flow control of the hydraulic system, ensure that the working pump hydraulic motor, the steering pump hydraulic motor, the working pump and the steering pump always operate in an efficient interval, reduce energy loss, and realize energy-saving effect of the electric loader.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering machinery, and particularly relates to an electric loader hydraulic system and an electric loader. BACKGROUND

[0002] Most of the existing electric loaders are of a constant system and a variable system load-sensitive control, and the handle angle is only associated with the motor speed and has no direct correspondence with the system flow. The motor speed operating range is large, and the motor efficient range is not combined with the system flow output, so the heat loss in the working process of the motor and the hydraulic pump is not further reduced. Therefore, the hydraulic pump and the motor of the existing electric loader still have the problem of large energy consumption. SUMMARY

[0003] To solve the problems in the prior art, the present application provides an electric loader hydraulic system and an electric loader. The controller can control the motor speed and the hydraulic pump displacement according to different flow outputs, so that the motor and the hydraulic pump operate in the efficient range, and the corresponding flow can be output according to the front-end signal to realize accurate flow control and further reduce the energy consumption of the hydraulic pump and the motor.

[0004] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0005] In a first aspect, an electric loader hydraulic system is provided, comprising: a working pump hydraulic motor for driving a working pump and a steering pump hydraulic motor for driving a steering pump; an outlet of the working pump is connected to an oil port P2 of a distribution valve and a pilot oil source valve; the distribution valve is used to drive an arm cylinder and a bucket cylinder; the pilot oil source valve controls the distribution valve through a pilot valve; an outlet of the steering pump is connected to an inlet of a flow amplification valve and an oil port P1 of the pilot oil source valve; a working port of the flow amplification valve is connected to a steering cylinder; an oil port PF of the flow amplification valve is connected to an outlet of the working pump; an outlet of the pilot oil source valve is connected to an inlet of a steering gear; the steering gear is used to realize steering action by controlling the flow amplification valve; a controller collects the pilot pressure of each control port of the distribution valve, the outlet pressure of the working pump, and the rotation angular velocity of the steering gear, and matches the displacement of the working pump with the rotation speed of the working pump hydraulic motor, matches the handle opening degree with the displacement of the working pump and the rotation speed of the working pump hydraulic motor, and matches the rotation angular velocity of the steering gear with the displacement of the steering pump and the rotation speed of the steering pump hydraulic motor, so as to realize positive flow control of the hydraulic system, ensure that the working pump hydraulic motor, the steering pump hydraulic motor, the working pump and the steering pump always operate in the efficient range, reduce energy loss, and achieve the energy-saving effect of the electric loader.

[0006] Furthermore, the controller controls the displacement of the working pump and the speed of the working pump hydraulic motor, the displacement of the steering pump and the speed of the steering pump hydraulic motor according to the pilot pressure collected from each control port of the distribution valve to meet the following conditions respectively, thereby achieving the output of the flow required by the system at different positions of the handle while making the working pump hydraulic motor, the working pump, the steering pump hydraulic motor and the steering pump all work in the high-efficiency range,

[0007] Condition one:

[0008] Condition two:

[0009] in, Indicates the lower limit torque of the motor's high efficiency range; Indicates the upper limit torque of the motor's high efficiency range; Indicates the displacement of the hydraulic pump; Indicates the output pressure of the hydraulic pump; Indicates the lower limit speed of the motor's high efficiency range; Indicates the upper limit speed of the motor’s high efficiency range, Indicates the speed of the motor; when the motor is a working pump hydraulic motor, the hydraulic pump is the working pump; when the motor is a steering pump hydraulic motor, the hydraulic pump is the steering pump.

[0010] Furthermore, according to condition one and condition two, the working pump flow output curve and the steering pump flow output curve are drawn respectively and input into the controller to associate the handle pressure output and the steering gear rotation angular velocity with the system flow; the flow output curves input into the controller are divided into several groups according to the size of the pump port pressure, and the pump port pressure is used to identify the current state to match the flow output curve.

[0011] Furthermore, when the steering wheel is slightly turned, if the steering gear's rotational angular velocity is less than the set value, the steering pump's swash plate angle remains unchanged, the steering pump's hydraulic motor remains at idle speed, and outputs the required steering flow. When the steering wheel is turned quickly, the controller determines the system's output flow based on the steering gear's rotational angular velocity:

[0012]

[0013]

[0014] in, The pressure oil volume required for the steering cylinder; is the steering gear displacement; is the angular velocity of the steering gear; is the amplification ratio of the flow amplification valve; is the displacement of the steering pump; is the steering pump speed; while ensuring the steering pump flow output, the steering pump displacement and the steering pump hydraulic motor speed are matched in real time according to the drawn steering pump flow output curve, so as to realize the steering pump hydraulic motor and steering pump running in the high-efficiency range.

[0015] Furthermore, when the distribution valve spool and the steering gear are both in the middle position, the steering pump hydraulic motor is in idle state and the working pump hydraulic motor speed is zero. At this time, the distribution valve spool middle position is in the PT small opening state, and the steering pump outputs a set small flow rate to reduce the starting impact when the working device starts to move.

[0016] Furthermore, when the operating handle of the pilot valve controls the working device in the micro-control area, the steering pump is in a set low displacement state, the speed is idling, and the working pump hydraulic motor is in a non-working state. The operating handle of the micro-motion pilot valve is within the set pilot pressure output range, and the steering pump displacement remains unchanged. The entire micro-control range controls the flow of the working device through the movement of the valve stem to ensure the micro-controllability of the working device.

[0017] Furthermore, when the operating handle of the pilot valve leaves the micro-control area to control the working device, this working condition is combined with the valve stem area curve of the distribution valve. When the operating handle of the pilot valve moves out of the micro-control area, the area from the P port of the distribution valve stem to the large cavity of the boom becomes the largest, and the actual movement speed of the working device is changed to motor speed control. The pilot pressure output by the operating handle of the pilot valve is related to the flow of the hydraulic system. The flow output of the hydraulic system is determined by the drawn working pump flow output curve. At this time, the output flow of the working pump is the actual flow required by the system, which is used to reduce the PA pressure loss and reduce the energy consumption of the whole machine, so that the working pump hydraulic motor and the working pump operate in the high-efficiency range, thereby achieving system energy saving.

[0018] Furthermore, when the steering pump and the working pump are controlled at the same time, the steering pump hydraulic motor and the working pump hydraulic motor are both in working state. At this time, the controller obtains the flow information required by the system through the angular velocity of the pilot valve and the steering gear. The hydraulic motor and the hydraulic pump determine the speed and displacement according to the drawn working pump flow output curve and the steering pump flow output curve, which is used to make the hydraulic system operate in the high-efficiency range, thereby achieving system energy saving and precise flow output.

[0019] Furthermore, a working condition recognition logic is set to avoid the arm lifting limit and energy waste caused by excessive traction of the travel motor when the loader is in the shoveling and rising working condition; the working condition recognition logic includes: collecting the arm large cavity pressure pd, the working pump pump port pressure p1 and the vehicle speed, when

[0020] Vehicle speed ≤ a km / h;

[0021] p1-pd≤△p;

[0022] pd≤pg (working pressure-△p);

[0023] At this time, it is believed that the loader is inserted into the pile to perform the boom lifting action. According to this logic, the traction force of the travel motor is reduced to reduce the energy consumption of the entire machine. At the same time, the bucket is protected from the reaction force of the traction force and the force of the boom lifting is increased.

[0024] In a second aspect, an electric loader is provided, wherein the electric loader is equipped with the electric loader hydraulic system according to the first aspect.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention collects the pilot pressure of each control port of the distribution valve, the outlet pressure of the working pump, and the angular velocity of the steering gear through the controller, and matches the displacement of the working pump with the rotation speed of the working pump hydraulic motor, matches the handle opening with the displacement of the working pump and the rotation speed of the working pump hydraulic motor, and matches the angular velocity of the steering gear with the displacement of the steering pump and the rotation speed of the steering pump hydraulic motor, so as to realize positive flow control of the hydraulic system, and at the same time ensure that the working pump hydraulic motor, the steering pump hydraulic motor, the working pump and the steering pump always operate in the high-efficiency range, and at the same time can output the corresponding flow according to the front-end signal, realize precise flow control, reduce energy loss, further reduce the energy consumption of the hydraulic pump and the motor, and realize the energy-saving effect of the electric loader. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the hydraulic system principle of an electric loader provided by an embodiment of the present invention;

[0027] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of the middle distribution valve;

[0028] In the figure: 1. Working pump hydraulic motor; 2. Working pump; 3. Steering pump; 4. Steering gear; 5. Limit valve 1; 6. Limit valve 2; 7. Flow amplification valve; 8. Angle sensor; 9. Steering cylinder; 10. Pilot oil source valve; 11. Pressure switch; 12. Hydraulic lock; 13. Pilot valve; 14. Pressure sensor; 15. Boom cylinder; 16. Bucket cylinder; 17. Distribution valve; 18. Controller; 19. Steering pump hydraulic motor. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0030] Example 1

[0031] like Figure 1 、 Figure 2As shown, a hydraulic system of an electric loader includes: a working pump hydraulic motor 1, a working pump 2, a steering pump 3, a steering gear 4, a limit valve 1 5, a limit valve 2 6, a flow amplification valve 7, an angle sensor 8, a steering cylinder 9, a pilot oil source valve 10, a pressure switch 11, a hydraulic lock 12, a pilot valve 13, a pressure sensor 14, a boom cylinder 15, a bucket cylinder 16, a distribution valve 17, a controller 18, and a steering pump hydraulic motor 19.

[0032] The working pump hydraulic motor 1 is connected to the working pump 2, and the working pump hydraulic motor 1 is used to drive the working pump 2 to work. The outlet of the working pump 2 is respectively connected to the distribution valve 17 and the oil port P2 of the pilot oil source valve 10, the oil port A2 of the distribution valve 17 is connected to the large chamber of the boom cylinder 15, the oil port B2 is connected to the small chamber of the boom cylinder 15, the oil port A1 is connected to the large chamber of the bucket cylinder 16, and the oil port B1 is connected to the small chamber of the bucket cylinder 16; the distribution valve 17 is used to drive the boom cylinder 15 and the bucket cylinder 16 to work; the pilot oil source valve 10 controls the reversing of the distribution valve 17 through the pilot valve 13.

[0033] The steering pump hydraulic motor 19 is connected to the steering pump 3. The steering pump hydraulic motor 19 is used to drive the steering pump 3 to work. The steering pump 3 is connected to the flow amplification valve 7 and the oil port P1 of the pilot oil source valve. The oil port A and the oil port B of the flow amplification valve 7 are connected to the steering cylinder 9, and the PF port is connected to the pump port of the working pump 2.

[0034] The oil port P2 of the pilot oil source valve 10 is connected to the working pump 2, and the oil port U is respectively connected to the oil port P of the steering gear 4 and the pressure switch 11, and is connected to the oil port P of the pilot valve 13 through the hydraulic lock 12. The steering gear 4 is used to realize the steering action by controlling the reversing of the flow amplification valve 7.

[0035] The pressure sensor 14 is respectively connected to the oil port a1, oil port a2, oil port b1, oil port b2 of the distribution valve 17 and the working pump 2. The oil port a1, oil port a2, oil port b1, oil port b2 of the distribution valve 17 are simultaneously connected to the oil port a1, oil port a2, oil port b1, oil port b2 of the pilot valve 13. The pressure sensor 14 is also connected to the controller 18; the oil port L1 and oil port R1 of the flow amplification valve 7 are respectively connected to the limit valve 1 5 and the limit valve 2 6. The limit valve 1 5 and the limit valve 2 6 are respectively connected to the steering gear 4. The steering gear 4 is connected to the angle sensor 8. The angle sensor 8 is connected to the controller 18. The controller 18 is connected to the working pump hydraulic motor 1 and the steering pump hydraulic motor 19.

[0036] The controller 18 collects the pilot pressure of each control port of the distribution valve 17, the outlet pressure of the working pump 2, and the rotational angular velocity of the steering gear 4, and matches the displacement of the working pump 2 with the rotational speed of the working pump hydraulic motor 1, matches the handle opening with the displacement of the working pump 2 and the rotational speed of the working pump hydraulic motor 1, and matches the rotational angular velocity of the steering gear 4 with the displacement of the steering pump 3 and the rotational speed of the steering pump hydraulic motor 19, so as to realize positive flow control of the hydraulic system, and at the same time ensure that the working pump hydraulic motor 1, the steering pump hydraulic motor 19, the working pump 2 and the steering pump 3 always operate in the high-efficiency range, reduce energy loss, and achieve energy-saving effect of the electric loader.

[0037] The control logic of the present invention is as follows: First, the relationship between the flow rate in the controller and the speed of the hydraulic motor, the displacement of the hydraulic pump, and the pump port pressure is established. According to the hydraulic motor map, the torque and speed values ​​in the high-efficiency operating range can be intercepted to draw a curve showing the relationship between the motor speed and the hydraulic pump displacement. Specifically, the controller 18 controls the displacement of the working pump 2 and the speed of the working pump hydraulic motor 1, the displacement of the steering pump 3 and the speed of the steering pump hydraulic motor 19 according to the pilot pressure collected from each control port of the distribution valve 17, so that they meet the following conditions respectively, thereby achieving the output of the flow required by the system at different positions of the handle while making the working pump hydraulic motor, the working pump, the steering pump hydraulic motor and the steering pump all work in the high-efficiency range.

[0038] Condition one:

[0039] Condition two:

[0040] in, Indicates the lower limit torque of the motor's high efficiency range; Indicates the upper limit torque of the motor's high efficiency range; Indicates the displacement of the hydraulic pump; Indicates the output pressure of the hydraulic pump (the pressure is divided into several sections according to the pump port pressure sensor, corresponding to several groups of flow curves); Indicates the lower limit speed of the motor's high efficiency range; Indicates the upper limit speed of the motor’s high efficiency range, Indicates the speed of the motor; when the motor is a working pump hydraulic motor, the hydraulic pump is the working pump; when the motor is a steering pump hydraulic motor, the hydraulic pump is the steering pump.

[0041] According to condition one and condition two, the working pump flow output curve and the steering pump flow output curve are drawn respectively and input into the controller to associate the handle pressure output and the steering gear's rotational angular velocity with the system flow; the flow output curves input into the controller can be divided into several groups according to the size range of the pump port pressure, and the pump port pressure is used to identify the current state to match the flow output curve.

[0042] When the handle pressure sensor and the steering pressure sensor have no pressure output, the working pump 2 and the steering pump 3 are in a low displacement state, and the working pump hydraulic motor 1 is in a non-working state, the steering pump hydraulic motor 19 is in an idle state, a small flow output is maintained, the pump port hydraulic oil of the steering pump 3 returns to the tank through the oil port PF of the flow amplification valve 7 from the throttle of the valve rod P-T of the open-center multi-way valve (distribution valve 17), and a small hydraulic oil flow is always maintained to reduce the starting impact when the working device is actuated, and the throttle loss at the throttle port of the pump port small displacement output multi-way valve (distribution valve 17) is small.

[0043] When the steering wheel is slightly rotated, that is, only the steering wheel is rotated at a small angle, the angle sensor 8 collects the rotation rate (rotation angular velocity) of the steering gear 4, and if the rotation angular velocity of the steering gear 4 is less than a set value, it is considered that the driver needs to control the whole machine, the handle has no pressure signal output, the system output flow is a micro-control section flow, the working pump hydraulic motor does not rotate, the swash plate angle of the steering pump 3 remains unchanged, the steering pump hydraulic motor is in an idle state, and the steering pump displacement is a low displacement. At this time, the flow output meets the requirement of steering micro-control, and there is basically no additional throttle loss. When the steering wheel is rapidly rotated and the handle has no signal output, the working pump is in a non-working state, the controller determines the current flow output according to the handle end pressure signal and the steering sensor output signal, and the system flow output is executed according to the flow curve read by the controller, that is, the controller determines the system output flow according to the rotation angular velocity of the steering gear 4:

[0044]

[0045]

[0046] wherein, is the required pressure oil volume of the steering cylinder; is the displacement of the steering gear; is the rotation angular velocity of the steering gear; is the amplification ratio of the flow amplification valve; is the displacement of the steering pump; is the rotation speed of the steering pump;

[0047] While ensuring the flow output of the steering pump, the steering pump displacement and the steering pump hydraulic motor rotation speed are matched in real time according to the drawn steering pump flow output curve, so as to realize the operation of the steering pump hydraulic motor and the steering pump in the high-efficiency interval.

[0048] When only the micro-handle is used to operate the working device, the controller recognizes that the steering sensor has no signal output and the handle sensor pressure signal output value is small (the sensor pressure signal is divided into three sections), which belongs to the micro-control section signal. At this time, the working pump hydraulic motor does not rotate, the steering pump hydraulic motor keeps idling, and the steering pump displacement remains at a small value. The micro-control section controls the flow entering the tooling device by moving the valve stem of the distribution valve to ensure the micro-control performance of the working device.

[0049] When the operating handle leaves the micro-control area (the pressure signal is higher than the set value), the spring force of the distribution valve lifting and bucket retraction positions is designed to be low when the valve core is fully open, so that the handle output pressure is higher than the maximum spring force of the bucket retraction position and the bucket position. The valve core has been completely reversed. At this time, the speed control of the working device is achieved by the system flow output, which is different from the traditional throttling control. The energy loss generated when the oil passes through the distribution valve is reduced, and the flow capacity of the pump port oil to the working device pressure oil through the distribution valve is increased, avoiding throttling speed control pressure loss. The actual working device speed is controlled by the pump speed and displacement. The speed and displacement parameters are executed according to the controller input flow curve.

[0050] When steering and working are controlled at the same time, the steering pump hydraulic motor and the working pump hydraulic motor are both in working state. At this time, the controller obtains the flow information required by the system through the pilot valve and the steering gear rotation speed. The hydraulic motor and hydraulic pump are given the motor speed and displacement according to the flow curve input to the controller, so that the hydraulic system operates in the high-efficiency range, achieving system energy saving and precise flow output.

[0051] When it is detected that the pump port pressure reaches a specific pressure, it is considered that the system is in a pressure-holding state. At this time, the speed of the working pump hydraulic motor is reduced to zero, and the steering pump displacement is reduced, and the speed of the steering pump hydraulic motor is reduced to avoid increased energy consumption and system heating.

[0052] When the loader is in the shoveling and lifting state, due to the excessive traction, the bucket is inserted into the pile and is subjected to the traction reaction force, which is applied to the bucket, making the lifting force required by the whole machine greater and the required energy consumption increased. In order to avoid the arm lifting limit and energy waste caused by the excessive traction of the travel motor, the working condition recognition logic is added to the system. The boom cavity pressure pd, the working pump pump port pressure p1 and the vehicle speed signal are collected.

[0053] Vehicle speed ≤ a km / h;

[0054] p1-pd≤△p;

[0055] pd≤pg (working pressure-△p);

[0056] At this time, it is believed that the loader is inserted into the pile to perform the boom lifting action. According to this logic, the traction force of the travel motor is reduced to reduce the energy consumption of the entire machine. At the same time, the bucket is protected from the reaction force of the traction force and the force of the boom lifting is increased.

[0057] In order to achieve the energy-saving effect of the electric loader, the present invention decouples the working pump from the steering pump and uses the controller as the core brain of the entire vehicle. The controller can control the motor speed and hydraulic pump displacement according to different flow outputs, so that the motor and hydraulic pump operate in the high-efficiency range. At the same time, it can output the corresponding flow according to the front-end signal to achieve precise flow control.

[0058] Example 2

[0059] Based on the electric loader hydraulic system described in the first embodiment, this embodiment provides an electric loader, which is equipped with the electric loader hydraulic system described in the first embodiment.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hydraulic system for an electric loader, characterized in that: include: A working pump hydraulic motor (1) for driving a working pump (2) and a steering pump hydraulic motor (19) for driving a steering pump (3); The outlet of the working pump (2) is connected to the oil port P2 of the distribution valve (17) and the pilot oil source valve (10) respectively; the distribution valve (17) is used to drive the boom cylinder (15) and the bucket cylinder (16) to work; the pilot oil source valve (10) controls the reversing of the distribution valve (17) through the pilot valve (13); The outlet of the steering pump (3) is connected to the inlet of the flow amplification valve (7) and the oil port P1 of the pilot oil source valve (10), the working port of the flow amplification valve (7) is connected to the steering cylinder (9), and the oil port PF of the flow amplification valve (7) is connected to the outlet of the working pump (2); The outlet of the pilot oil source valve (10) is connected to the inlet of the steering gear (4), and the steering gear (4) is used to realize the steering action by controlling the switching of the flow amplification valve (7); The controller (18) collects the pilot pressure of each control port of the distribution valve (17), the outlet pressure of the working pump (2), and the rotational angular velocity of the steering gear (4), and matches the displacement of the working pump (2) with the rotational speed of the working pump hydraulic motor (1), matches the handle opening with the displacement of the working pump (2) and the rotational speed of the working pump hydraulic motor (1), and matches the rotational angular velocity of the steering gear (4) with the displacement of the steering pump (3) and the rotational speed of the steering pump hydraulic motor (19), so as to realize positive flow control of the hydraulic system and ensure that the working pump hydraulic motor (1), the steering pump hydraulic motor (19), the working pump (2) and the steering pump (3) always operate in a high-efficiency range, thereby reducing energy loss and achieving energy saving effect of the electric loader; The controller (18) controls the displacement of the working pump (2) and the speed of the working pump hydraulic motor (1), the displacement of the steering pump (3) and the speed of the steering pump hydraulic motor (19) according to the pilot pressure of each control port of the distribution valve (17) collected, so as to meet the following conditions respectively, thereby achieving the output of the flow required by the system at different positions of the handle while making the working pump hydraulic motor, the working pump, the steering pump hydraulic motor and the steering pump all work in the high-efficiency range. Condition 1: , Condition 2: , in, Indicates the lower limit torque of the motor's high efficiency range; Indicates the upper limit torque of the motor's high efficiency range; Indicates the displacement of the hydraulic pump; Indicates the output pressure of the hydraulic pump; Indicates the lower limit speed of the motor's high efficiency range; Indicates the upper limit speed of the motor’s high efficiency range, Indicates the speed of the motor; when the motor is a working pump hydraulic motor, the hydraulic pump is the working pump; when the motor is a steering pump hydraulic motor, the hydraulic pump is the steering pump; When the steering wheel is slightly turned, if the rotational angular velocity of the steering gear (4) is less than the set value, the swash plate angle of the steering pump (3) remains unchanged, the steering pump hydraulic motor (19) remains at an idle speed, and outputs the required flow rate for steering; when the steering wheel is turned quickly, the controller determines the system output flow rate according to the rotational angular velocity of the steering gear (4): ， ， in, The pressure oil volume required for the steering cylinder; is the steering gear displacement; is the angular velocity of the steering gear; is the amplification ratio of the flow amplification valve; is the displacement of the steering pump; is the steering pump speed; While ensuring the flow output of the steering pump, the steering pump displacement and the steering pump hydraulic motor speed are matched in real time according to the drawn steering pump flow output curve, so as to realize the operation of the steering pump hydraulic motor and the steering pump in the high-efficiency range.

2. The electric loader hydraulic system according to claim 1, characterized in that: According to conditions one and two, the working pump flow output curve and the steering pump flow output curve are drawn respectively and input into the controller to associate the handle pressure output and the steering gear's rotational angular velocity with the system flow; the flow output curves input into the controller are divided into several groups according to the size of the pump port pressure, and the pump port pressure is used to identify the current state to match the flow output curve.

3. The electric loader hydraulic system according to claim 2, characterized in that: When the valve core of the distribution valve (17) and the steering gear (4) are both in the middle position, the steering pump hydraulic motor (19) is in the idle state, and the speed of the working pump hydraulic motor (1) is zero. At this time, the valve core of the distribution valve (17) is in the PT small opening state, and the steering pump (3) outputs a set small flow rate to reduce the starting impact when the working device starts to move.

4. The electric loader hydraulic system according to claim 2, characterized in that: When the operating handle of the pilot valve (13) controls the working device in the micro-control area, the steering pump (3) is in a set low displacement state, the speed is idling, and the working pump hydraulic motor (1) is in a non-working state. The operating handle of the micro-motion pilot valve (13) is within the set pilot pressure output range, and the displacement of the steering pump (3) remains unchanged. The entire micro-control range controls the flow of the working device through the movement of the valve stem, which is used to ensure the micro-controllability of the working device.

5. The electric loader hydraulic system according to claim 4, characterized in that: When the operating handle of the pilot valve (13) leaves the micro-control area to control the working device, this working condition is combined with the valve stem area curve of the distribution valve (17). When the operating handle of the pilot valve (13) moves to leave the micro-control area, the area from the P port of the valve stem of the distribution valve (17) to the large cavity of the boom becomes the largest, and the actual movement speed of the working device is changed to motor speed control. The pilot pressure output by the operating handle of the pilot valve (13) is related to the flow of the hydraulic system. The flow output of the hydraulic system is determined by the drawn working pump flow output curve. At this time, the output flow of the working pump is the actual flow required by the system, which is used to reduce the PA pressure loss and reduce the energy consumption of the whole machine, so that the hydraulic motor of the working pump and the working pump operate in the high-efficiency range, thereby achieving system energy saving.

6. The electric loader hydraulic system according to claim 2, characterized in that: When the steering pump (3) and the working pump (2) are controlled at the same time, the steering pump hydraulic motor (19) and the working pump hydraulic motor (1) are both in the working state. At this time, the controller (18) obtains the flow information required by the system through the rotational angular velocity of the pilot valve and the steering gear. The hydraulic motor and the hydraulic pump determine the speed and displacement according to the drawn working pump flow output curve and the steering pump flow output curve, so as to make the hydraulic system operate in the high-efficiency range and achieve system energy saving and accurate flow output.

7. The electric loader hydraulic system according to claim 2, characterized in that: Set the working condition recognition logic to prevent the travel motor from exerting excessive traction, which may lead to arm lifting restriction and energy waste, when the loader is in the shoveling and rising working condition; The working condition identification logic includes: collecting the boom cavity pressure pd, the working pump port pressure p1 and the vehicle speed. Vehicle speed ≤ a km / h; p1-pd≤△p; pd≤pg (working pressure-△p); At this time, it is believed that the loader is inserted into the pile to perform the boom lifting action. According to this logic, the traction force of the travel motor is reduced to reduce the energy consumption of the entire machine. At the same time, the bucket is protected from the reaction force of the traction force and the force of the boom lifting is increased.

8. An electric loader, characterized in that: The electric loader is equipped with the electric loader hydraulic system according to any one of claims 1 to 7.

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