An EHA device suitable for pump and valve co-control for negative loads

Abstract

The present application belongs to the field of hydraulic transmission and its control, and provides a pump-valve joint control EHA device suitable for negative load, which comprises a series motor pump, a check valve, an accumulator, an overflow valve, a cooler, an actuator cylinder, a servo valve, a hydraulic directional valve, an electromagnetic directional valve, a high-pressure filter, an oil suction filter, an oil tank and an electrical control system. The device can realize high frequency, low loss, clean and cool oil, oil tank oil supplement and actuator control redundancy backup under negative load. When the actuator is in negative load, the motor pump runs at low speed, the servo valve is controlled to realize external load pushing the actuator cylinder to reach the command position, the response frequency is improved, the power consumption and valve throttling noise are reduced, the oil is purified and cooled in real time, and when the motor, pump and other components fail, the external hydraulic oil source can be switched to supply oil, and the servo valve is used to control the actuator cylinder.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydraulic transmission and its control, and particularly relates to a pump-valve combined control EHA device suitable for negative load. BACKGROUND

[0002] A typical electrical-hydraulic actuator (EHA) is mainly composed of a motor, a hydraulic pump, a safety valve, an actuator cylinder and an oil tank, has the characteristics of high integration degree, compact structure and high efficiency, and is widely used in aircraft rudder systems. However, due to the slow response speed of the motor and the pump, it is difficult to meet the requirements of high response frequency occasions. In order to improve the response frequency of the system, domestic scholars proposed a technical scheme of pump-valve combined EHA, which combines a high-frequency response servo valve control system with a pump control system, adjusts the working process of pump control and servo valve control according to different working conditions and use requirements, so that the EHA can meet the frequency and response requirements. The pump-valve combined EHA combines the advantages of high valve control response and high pump control efficiency, but still has the following shortcomings: first, there is still throttling loss of valve control, especially in negative load conditions requiring high frequency response occasions; second, the self-oil cleaning and cooling capacity is insufficient, and the oil quality requirement is high; third, the motor pump still needs to be reversed to change the actuator actuation direction, the response frequency is low, the requirement for the hydraulic pump is high, and the electrical control system is more complex; fourth, in the event of motor pump failure, there is a lack of necessary redundancy backup, which is difficult to meet the requirements of high reliability task of the system. SUMMARY

[0003] The purpose of the present application is to eliminate the weaknesses of low frequency response, high motor forward and reverse requirements, insufficient oil cleaning and cooling capacity, and lack of redundancy design of EHA for rudder systems with high task reliability requirements and frequent negative load conditions, and to provide a pump-valve combined control EHA device suitable for negative load, which can realize high frequency, low loss, oil cleaning and cooling, oil tank oil supplement and actuation control redundancy backup under negative load conditions. When the actuator is in negative load condition, the motor pump operates at low speed, and the external load pushes the actuator cylinder to reach the command position through servo valve control, which improves the response frequency, reduces the power consumption and valve throttling noise, and realizes real-time purification and cooling of the oil. When the motor, pump and other components fail, the external hydraulic oil source can be switched to supply oil, and the servo valve can be used to control the actuator cylinder.

[0004] The purpose of the present application is achieved by the following technical measures.

[0005] An EHA device suitable for negative load pump valve joint control, comprising a series motor pump, a first check valve, a first accumulator, a first overflow valve, a cooler, a second overflow valve, a second check valve, a third check valve, an actuator cylinder, a servo valve, a hydraulic reversing valve, a first electromagnetic reversing valve, a second accumulator, a fourth check valve, a second electromagnetic reversing valve, a fifth check valve, a high pressure filter, a third overflow valve, an oil suction filter, an oil tank, an electrical control system; the series motor pump comprises a low displacement hydraulic pump and a large flow hydraulic pump, the P port of the low displacement hydraulic pump is connected with the P port of the third overflow valve and the high pressure filter, and the oil suction port is connected with the A port of the oil suction filter; the P port of the large flow hydraulic pump is connected with the A port of the first check valve, and the oil suction port is connected with the A port of the oil suction filter; the motor in the series motor pump is a variable frequency motor, the rotation speed feedback signal of which is connected with the electrical control system and receives variable frequency and start-stop control of the electrical control system; the A port of the first check valve is connected with the P port of the large flow hydraulic pump, and the B port is connected with the first overflow valve and the first accumulator; the first accumulator is connected with the B port of the first check valve and the P port of the first overflow valve and the P1 port of the hydraulic reversing valve; the T port of the first overflow valve is connected with the A port of the cooler; the A port of the cooler is connected with the T ports of the first overflow valve, the second overflow valve and the third overflow valve, the T1 port of the hydraulic reversing valve, the B port of the fifth check valve, and the T port of the cooler is connected with the oil tank; the P port of the second overflow valve is connected with the B port of the fourth check valve, the second accumulator, the A port of the first electromagnetic reversing valve, the K2 port of the hydraulic reversing valve and the Y port of the servo valve; the A ports of the second check valve and the third check valve are connected with the T port of the servo valve together, the B port of the second check valve is connected with the A port of the servo valve, and the B port of the third check valve is connected with the B port of the servo valve; the A port of the actuator cylinder is connected with the A port of the servo valve, the B port of the actuator cylinder is connected with the B port of the servo valve, and it feeds back displacement signal to the electrical control system; the P port of the servo valve is connected with the A port of the hydraulic reversing valve, and the T port is connected with the B port of the hydraulic reversing valve; the K1 port of the hydraulic reversing valve is connected with the control port K of the external hydraulic oil source, and the P2 port and the T2 port of the hydraulic reversing valve are respectively connected with the pressure oil port P and the return oil T of the external hydraulic oil source; the P port of the first electromagnetic reversing valve is connected with the pressure oil port P of the external hydraulic oil source; the second accumulator is connected with the B port of the fourth check valve and the A port of the first electromagnetic reversing valve; the A port of the fourth check valve is connected with the B port of the high pressure filter and the P port of the second electromagnetic reversing valve; the A port of the second electromagnetic reversing valve is connected with the A port of the fifth check valve; the B port of the fifth check valve is connected with the A port of the cooler; the A port of the high pressure filter is connected with the P port of the third overflow valve and the oil outlet of the low displacement hydraulic pump; the T port of the oil suction filter is connected with the oil tank.The electric control system receives a speed signal of the series motor pump and a displacement signal of the actuating cylinder, sends a frequency conversion control signal to the series motor pump, sends a control signal to the servo valve, and sends control signals to the first electromagnetic reversing valve and the second electromagnetic reversing valve.

[0006] In the technical scheme, the two hydraulic pumps of the series motor pump are coaxial and driven by a common frequency conversion motor; the series motor pump only performs frequency conversion speed regulation and does not perform forward and reverse rotation, and the forward and reverse movements of the actuating cylinder are controlled by the servo valve.

[0007] The pump-valve combined control EHA device has the following advantages: 1. low power consumption and low noise in a negative load condition, when the actuator is in a negative load condition (i.e. the direction of the external load force is the same as the direction of the actuating cylinder movement), the series motor pump outputs at a small flow (at this time, the noise is low), a valve control circuit is formed by the servo valve and two one-way valves in series with the actuating cylinder, and the actuating cylinder reaches the command position under the action of the control signal and the external load to realize low power consumption and low noise; 2. high response frequency, the motor pump outputs a flow that can be changed, the servo valve completes the reversing under the action of the control oil and the control signal when the actuating cylinder needs to reverse, thereby completing the reversing of the actuating cylinder; 3. self-oil cleaning and cooling, under normal circumstances, the low displacement pump of the series motor pump and the electromagnetic reversing valve in the circuit form a self-circulation circuit to realize oil purification and cooling; 4. high reliability of the task, when the motor, pump and other components fail, the external hydraulic oil source can be switched to supply oil, and the servo valve is used to control the actuating cylinder.

[0008] The application is suitable for a rudder surface control system with high integration degree, low power loss, high frequency response and low reversing impact, the series motor pump serves as a power source, an oil purification source and a system cooling oil source, the servo valve reverses to control the reversing of the actuating cylinder when the actuator moves, and the servo valve realizes the change to a typical valve control system when the series motor pump fails. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 The figure is a schematic diagram of the principle of the device.

[0010] In the figure, 1 is a series motor pump, 2 is a first one-way valve, 3 is a first accumulator, 4 is a first overflow valve, 5 is a cooler, 6 is a second overflow valve, 7 is a second one-way valve, 8 is a third one-way valve, 9 is an actuating cylinder, 10 is a servo valve, 11 is a hydraulic reversing valve, 12 is a first electromagnetic reversing valve, 13 is a second accumulator, 14 is a fourth one-way valve, 15 is a second electromagnetic reversing valve, 16 is a fifth one-way valve, 17 is a high-pressure filter, 18 is a third overflow valve, 19 is an oil suction filter, 20 is an oil tank, and 21 is an electric control system. DETAILED DESCRIPTION

[0011] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, specific embodiments of the present application will be described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application.

[0012] It is to be understood that where an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. Where an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can also be present.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0014] As Figure 1As shown, the embodiment of the present application provides an EHA device suitable for negative load pump valve joint control, which comprises a series motor pump 1, a first check valve 2, a first accumulator 3, a first overflow valve 4, a cooler 5, a second overflow valve 6, a second check valve 7, a third check valve 8, an actuator cylinder 9, a servo valve 10, a hydraulic directional valve 11, a first electromagnetic directional valve 12, a second accumulator 13, a fourth check valve 14, a second electromagnetic directional valve 15, a fifth check valve 16, a high-pressure filter 17, a third overflow valve 18, an oil suction filter 19, an oil tank 20, and an electrical control system 21. The series motor pump 1 comprises a low-displacement hydraulic pump 1.1 and a large-flow hydraulic pump 1.2, both of which are coaxial and driven by a common variable frequency motor. The series motor pump 1 only performs variable frequency speed regulation and does not perform forward and reverse rotation, and the forward and reverse movements of the actuator cylinder 9 are controlled by the servo valve 10.The P port of the low-displacement hydraulic pump 1.1 is connected with the P port of the third overflow valve 18 and the P port of the high-pressure filter 17, and the suction port is connected with the A port of the oil suction filter 19; the P port of the large-displacement hydraulic pump 1.2 is connected with the A port of the first one-way valve 2, and the suction port is connected with the A port of the oil suction filter 19; the motor 1.3 in the series motor pump 1 is a variable frequency motor, and the speed feedback signal thereof is connected with the electrical control system 21 and receives the variable frequency and start-stop control of the electrical control system 21; the A port of the first one-way valve 2 is connected with the P port of the large-displacement hydraulic pump 1.2, and the B port is connected with the first overflow valve 4 and the first accumulator 3; the B port of the first one-way valve 2 and the P port of the first overflow valve 4 and the P1 port of the hydraulic directional valve 11 are connected with the first accumulator 3; the T port of the first overflow valve 4 is connected with the A port of the cooler 5; the A port of the cooler 5 is connected with the T ports of the first overflow valve 4, the second overflow valve 6 and the third overflow valve 18, the T1 port of the hydraulic directional valve 11, the B port of the fifth one-way valve 16, and the T port of the cooler 5 is connected with the oil tank 20; the P port of the second overflow valve 6 is connected with the B port of the fourth one-way valve 14, the second accumulator 13, the A port of the first electromagnetic directional valve 12, the K2 port of the hydraulic directional valve 11 and the Y port of the servo valve 10; the A ports of the second one-way valve 7 and the third one-way valve 8 are connected with the T port of the servo valve 10 together, the B port of the second one-way valve 7 is connected with the A port of the servo valve 10, and the B port of the third one-way valve 8 is connected with the B port of the servo valve 10; the A port of the servo valve 10 is connected with the A port of the servo valve 10, and the B port of the servo valve 10 is connected with the B port of the servo valve 10, and the displacement signal thereof is fed back to the electrical control system 21; the P port of the servo valve 10 is connected with the A port of the hydraulic directional valve 11, and the T port is connected with the B port of the hydraulic directional valve 11; the K1 port of the hydraulic directional valve 11 is connected with the control port K of the external hydraulic oil source, and the P2 port and the T2 port of the hydraulic directional valve 11 are respectively connected with the pressure oil port P of the external hydraulic oil source and the return oil T port; the P port of the first electromagnetic directional valve 12 is connected with the pressure oil port P of the external hydraulic oil source; the second accumulator 13 is connected with the B port of the fourth one-way valve 14 and the A port of the first electromagnetic directional valve 12; the A port of the fourth one-way valve 14 is connected with the B port of the high-pressure filter 17 and the P port of the second electromagnetic directional valve 15; the A port of the second electromagnetic directional valve 15 is connected with the A port of the fifth one-way valve 16; the B port of the fifth one-way valve 16 is connected with the A port of the cooler 5; the A port of the high-pressure filter 17 is connected with the P port of the third overflow valve 18 and the oil outlet of the low-displacement hydraulic pump 1.1; the T port of the oil suction filter 19 is connected with the oil tank 20; the electrical control system 21 receives the speed signal of the series motor pump 1 and the displacement signal of the servo valve 10, sends the variable frequency control signal to the series motor pump 1, sends the control signal to the servo valve 10, and sends the control signal to the first electromagnetic directional valve 12 and the second electromagnetic directional valve 15.

[0015] The contents not described in detail in the present application belong to the prior art known to those skilled in the art.

[0016] Finally, it should be pointed out that the above embodiments are only more representative examples of the present application. Obviously, the present application is not limited to the above embodiments, but can also have various schemes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application should be considered to fall within the protection scope of the present application.

Claims

1. An EHA device suitable for pump and valve co-control of a negative load, characterized by: The application relates to a hydraulic system for a hydraulic cylinder, which comprises a series motor pump, a first check valve, a first accumulator, a first overflow valve, a cooler, a second overflow valve, a second check valve, a third check valve, an actuating cylinder, a servo valve, a hydraulic directional valve, a first electromagnetic directional valve, a second accumulator, a fourth check valve, a second electromagnetic directional valve, a fifth check valve, a high-pressure filter, a third overflow valve, an oil suction filter, an oil tank and an electric control system; the series motor pump comprises a low-displacement hydraulic pump and a large-flow hydraulic pump; the P port of the low-displacement hydraulic pump is connected with the P port of the third overflow valve and the A port of the high-pressure filter; the oil suction port of the low-displacement hydraulic pump is connected with the A port of the oil suction filter; the P port of the large-flow hydraulic pump is connected with the A port of the first check valve; the oil suction port of the large-flow hydraulic pump is connected with the A port of the oil suction filter; the motor in the series motor pump is a variable-frequency motor, the rotation speed feedback signal of which is connected with the electric control system and receives the variable-frequency and start-stop control of the electric control system; the A port of the first check valve is connected with the P port of the large-flow hydraulic pump; the B port of the first check valve is connected with the first overflow valve and the first accumulator; the first accumulator is connected with the B port of the first check valve, the P port of the first overflow valve and the P1 port of the hydraulic directional valve; the T port of the first overflow valve is connected with the A port of the cooler; the A port of the cooler is connected with the T ports of the first, second and third overflow valves, the T1 port of the hydraulic directional valve, the B port of the fifth check valve and the A port of the cooler; the T port of the cooler is connected with the oil tank; the P port of the second overflow valve is connected with the B port of the fourth check valve, the second accumulator, the A port of the first electromagnetic directional valve, the K2 port of the hydraulic directional valve and the Y port of the servo valve; the A ports of the second and third check valves are jointly connected with the T port of the servo valve; the B port of the second check valve is connected with the A port of the servo valve; the B port of the third check valve is connected with the B port of the servo valve; the A port of the actuating cylinder is connected with the A port of the servo valve; the B port of the actuating cylinder is connected with the B port of the servo valve; the actuating cylinder feeds a displacement signal to the electric control system; the P port of the servo valve is connected with the A port of the hydraulic directional valve; the T port of the servo valve is connected with the B port of the hydraulic directional valve; the K1 port of the hydraulic directional valve is connected with the control port K of an external hydraulic oil source; the P2 and T2 ports of the hydraulic directional valve are respectively connected with the pressure oil port P and the back oil T of the external hydraulic oil source; the P port of the first electromagnetic directional valve is connected with the pressure oil port P of the external hydraulic oil source; the second accumulator is connected with the B port of the fourth check valve and the A port of the first electromagnetic directional valve; the A port of the fourth check valve is connected with the B port of the high-pressure filter and the P port of the second electromagnetic directional valve; the A port of the second electromagnetic directional valve is connected with the A port of the fifth check valve; the B port of the fifth check valve is connected with the A port of the cooler; the A port of the high-pressure filter is connected with the P port of the third overflow valve and the oil outlet of the low-displacement hydraulic pump; the T port of the oil suction filter is connected with the oil tank.The electric control system receives a speed signal of the series motor pump and a displacement signal of the actuating cylinder, sends a variable frequency control signal to the series motor pump, sends a control signal to the servo valve, and sends control signals to the first electromagnetic reversing valve and the second electromagnetic reversing valve.

2. The EHA device for pump-valve co-control of negative loads according to claim 1, characterized in that: The two hydraulic pumps of the series motor pump are coaxial and driven by a common variable frequency motor; the series motor pump only performs variable frequency speed regulation and does not perform forward and reverse rotation, and the forward and reverse movements of the actuating cylinder are controlled by a servo valve.

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