A two-wire current output type liquid level sensor

Abstract

This invention relates to the field of liquid level sensor technology and discloses a two-wire current output type liquid level sensor. The angle-to-current conversion module located inside the housing includes, in sequence, a first power characteristic enhancement module, a power filter, a first electromagnetic effect enhancement module, a conditioning IC, a magnetic angle sensor, a conversion circuit, a second power characteristic enhancement module, and a second power characteristic enhancement module. The power input terminal of the first power characteristic enhancement module is electrically connected to a socket, and the signal output terminal of the second power characteristic enhancement module is connected to the negative terminal of the socket. The two ends of a connector located outside the housing are respectively connected to a piston and a steel rope located inside the housing. The steel rope is connected to a first transmission mechanism, and the first transmission mechanism is connected to a second transmission mechanism. The magnetic angle sensor is mounted on the second transmission mechanism and connected to the conversion circuit. The conversion circuit acquires the voltage value across the magnetoresistor in the magnetic angle sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level sensors, in particular to a two-wire current output type liquid level sensor used for detecting the liquid level of a hydraulic oil tank of an aircraft. Background Art

[0002] Traditional closed container volume monitoring generally measures the volume indirectly by measuring the piston stroke. There are wire displacement sensors, LVDT, composite sensors, etc. Usually, these sensors can only mechanically indicate or output resistance or output voltage or three-wire 4-20mA output, and the electromagnetic protection, power supply compatibility, and lightning protection characteristics are poor, which can no longer meet the current development needs of aircraft. With the continuous development of aircraft design technology, aircraft lightweight, high maneuverability, and long-range have become the focus of aircraft research and development design. Among them, lightweight must be implemented in all aspects of aircraft design, including materials and structures. Traditional voltage and three-wire 4-20mA outputs require at least three wires during signal transmission, which causes the aircraft to increase weight due to cables, which violates the aircraft weight reduction requirements. At the same time, traditional sensors are open structures, and the internal circuits are exposed to the electromagnetic environment. The electromagnetic protection performance is poor, and the electromagnetic protection performance must be guaranteed through circuit packaging and circuit design; traditional sensors do not consider 28V DC power supply compatibility and lightning protection. Sensors are easily damaged when the aircraft is powered off, the circuit is reversed, the power supply is impacted, and lightning strikes occur. The two-wire 4-20mA current output type liquid level sensor meets the current aircraft use requirements by reducing signal transmission wires, increasing electromagnetic protection, improving 28V DC power supply compatibility, and increasing lightning protection.

[0003] The inventor made further optimization and improvements based on his prior patent with application number 202022628478.2. Summary of the invention

[0004] The object of the present invention is to provide a two-wire current output type liquid level sensor, which can realize the function of measuring the liquid level of a hydraulic oil tank and has the beneficial effects of stable signal and high measurement accuracy.

[0005] The present invention is achieved through the following technical solutions:

[0006] A two-wire current output type liquid level sensor, comprising a housing, an angle-to-current module, a transmission mechanism, a connector and a socket; the angle-to-current module and the transmission mechanism are located inside the housing, and the connector and the socket are located outside the housing;

[0007] The transmission mechanism comprises a steel rope and a first transmission mechanism and a second transmission mechanism connected to each other; a piston is slidably provided in the inner hole of the joint, one end of the steel rope extends into the inner hole of the joint and is fixedly connected to the piston, and the other end of the steel rope (16) extends into the interior of the housing and is connected to the first transmission mechanism;

[0008] The angle-to-current module includes a first power characteristic enhancement module, a power filter, a first electromagnetic effect enhancement module, a conditioning IC, a magnetic angle sensor, a conversion circuit, a second power characteristic enhancement module, and a second power characteristic enhancement module, which are connected in sequence by electrical signals, wherein the power input end of the first power characteristic enhancement module is connected to the socket electrical signal, and the signal output end of the second power characteristic enhancement module is connected to a signal line, and the signal line is connected to the negative pole of the socket; the magnetic angle sensor is installed on the second transmission mechanism and is connected to the conversion circuit; the conversion circuit collects the voltage value at both ends of the magnetoresistor in the magnetic angle sensor.

[0009] In order to better implement the present invention, further, the first transmission mechanism includes a first rotating shaft, a roller, a first gear, a bearing, and a spiral spring;

[0010] The bearing is fixedly installed in the housing, a first rotating shaft is rotatably installed on the bearing, a first gear and a drum are respectively installed on the first rotating shaft, one end of the steel rope is fixedly wound on the drum, and the other end is connected to a joint located outside the housing; the inner end of a spiral spring for providing a restoring force to the first rotating shaft is fixedly connected to the first rotating shaft, a clockwork box is fixedly installed in the housing, the spiral spring is located in the clockwork box, and the outer end of the spiral spring is fixed to the inner wall of the clockwork box;

[0011] The magnetic angle sensor is fixedly installed in the housing, the second rotating shaft is connected to the magnetic angle sensor, and the second gear is arranged on the second rotating shaft and meshes with the first gear.

[0012] In order to better implement the present invention, further, the shell has a top opening, an upper cover is installed at the top opening, and the upper cover has a transparent window; a display meter is provided in the shell corresponding to the area where the transparent window is located, the second rotating shaft is coaxial with the center of the display meter, and the display meter has a pointer that rotates with the second rotating shaft.

[0013] In order to better realize the present invention, it further includes a bayonet, a thread is arranged on the periphery of the bayonet, a corresponding thread is arranged on the inner hole of the joint, the bayonet and the joint are adjustably connected together through the thread, a sealing plug is arranged in the inner hole of the joint to separate the inside of the shell from the outside, and the other end of the steel rope passes through the sealing plug and extends into the inside of the shell to be connected with the drum.

[0014] In order to better implement the present invention, further, a spring is provided between the bayonet and the piston.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] The invention has the beneficial effects of high measurement accuracy, long service life, two-wire output, long-distance signal output and reduced product cable weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The technical solution will be described clearly and completely below in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0018] Figure 1 A schematic diagram of the structure of a two-wire current output type liquid level sensor provided by the present invention;

[0019] Figure 2 is a schematic diagram of a display table of the present invention;

[0020] Figure 3 It is a schematic diagram of the signal flow of the angle-to-current module of the present invention.

[0021] Among them: 1. Shell; 2. Upper cover; 3. Transparent window; 4. Second gear; 5. Socket; 6. Angle to current module; 7. Clockwork box; 8. Vortex spring; 9. First gear; 10. First rotating shaft; 11. Drum; 12. Bearing; 13. Pointer; 14. Display table; 15. Sealing plug; 16. Steel rope; 17. Spring; 18. Bayonet; 19. Second rotating shaft; 20. Joint; 21. Piston. DETAILED DESCRIPTION

[0022] The above contents of the invention are further described in detail below in conjunction with the specific implementation methods of the embodiments. However, this should not be understood as the scope of the above subject matter of the invention being limited to the following examples. Various substitutions or changes made according to common technical knowledge and customary means in the art without departing from the above technical ideas of the invention should be included in the scope of the invention.

[0023] Embodiment 1:

[0024] A two-wire current output type liquid level sensor of this embodiment, such as Figure 1-Figure 3 As shown, it includes a housing 1, an angle-to-current module 6 installed in the housing 1, a transmission mechanism, and a connector 20 and a socket 5 installed outside the housing 1;

[0025] The angle-to-current module 6 located in the housing 1 includes a first power characteristic enhancement module, a power filter, a first electromagnetic effect enhancement module, a conditioning IC, a magnetic angle sensor, a conversion circuit, a second power characteristic enhancement module, and a second power characteristic enhancement module, which are sequentially connected by electrical signals. The power input end of the first power characteristic enhancement module is electrically connected to the socket 5, and the signal output end of the second power characteristic enhancement module is connected to a signal line, and the signal line is connected to the negative pole of the socket 5;

[0026] The transmission mechanism includes a first transmission mechanism, a second transmission mechanism, and a steel rope 16;

[0027] The two ends of the joint 20 located outside the housing 1 are respectively connected to the piston 21 and the steel rope 16 located inside the housing 1, the steel rope 16 is connected to the first transmission mechanism, the first transmission mechanism is connected to the second transmission mechanism, the magnetic angle sensor is installed on the second transmission mechanism, and is connected to the conversion circuit;

[0028] The conversion circuit collects the voltage value across the magnetoresistor in the magnetoresistive angle sensor.

[0029] In this implementation, the first power supply characteristic enhancement module and the second power supply enhancement module are used to provide surge protection, reverse connection protection, power failure protection and other functions; the first electromagnetic effect characteristic module and the second electromagnetic effect enhancement module are used to provide electromagnetic compatibility, lightning protection, anti-static and other functions, and the internal components include filters, lightning protection TVS diodes and other components; the final second power supply characteristic enhancement module outputs a 4~20mA current signal, and uses the negative pole in the socket 5 as the external signal line to achieve a two-wire output, reducing the use of cables and facilitating the weight reduction of the aircraft. The magnetic angle sensor is used to detect the rotation angle displacement in time, and the internal magnetic resistor senses the angle change. The voltage at both ends of the magnetic resistor is collected through the conversion circuit to achieve high-precision and high temperature drift resistance detection. The conversion circuit is an AD conversion circuit, which converts the AC current output by the magnetic angle sensor into a DC current. The conditioning IC model is NSA2860, which is used to output a constant current source. The magnetic angle sensor receives the angular displacement received by the magnetic angle sensor and the constant current source output by the conditioning IC is converted into a linear voltage signal that changes with the angular displacement.

[0030] Embodiment 2:

[0031] This embodiment is obtained by further optimizing the embodiment 1. Figure 1 and Figure 2 As shown, the first transmission mechanism includes a first rotating shaft 10, a roller 11, a first gear 9, a bearing 12, and a volute spring 17;

[0032] The bearing 12 is fixedly installed in the housing 1, and a first rotating shaft 10 is rotatably installed on the bearing 12. The first gear 9 and the drum 11 are respectively installed on the first rotating shaft 10. One end of the steel rope 16 is fixedly wound on the drum 11, and the other end is connected to a joint 20 located outside the housing 1; the inner end of a spiral spring 17 for providing a restoring force to the first rotating shaft 10 is fixedly connected to the first rotating shaft 10, and a clockwork box 7 is fixedly installed in the housing 1, and the spiral spring 17 is located in the clockwork box 7 and the outer end of the spiral spring 17 is fixed to the inner wall of the clockwork box 7;

[0033] The magnetic angle sensor is fixedly installed in the housing 1 , the second rotating shaft 19 is connected to the magnetic angle sensor, and the second gear 4 is arranged on the second rotating shaft 19 and meshes with the first gear 9 .

[0034] The shell 1 has an open top, and an upper cover 2 is installed at the top opening, and the upper cover 2 has a transparent window 3; a display meter 14 is provided in the shell 1 in an area corresponding to the transparent window 3, and the second rotating shaft 19 is coaxial with the center of the display meter 14, and the display meter 14 has a pointer 13 that rotates with the second rotating shaft 19.

[0035] It also includes a bayonet 18, the outer periphery of the bayonet 18 is provided with a thread, the inner hole of the joint 20 is provided with a corresponding thread, the bayonet 18 and the joint 20 are adjustably connected together through the thread, a piston 21 is slidably provided in the inner hole of the joint 20, and a sealing plug 15 is provided in the inner hole of the joint 20 to separate the inside of the shell 1 from the outside, the steel rope 16 is fixedly connected to the piston 21, and the other end of the steel rope 16 passes through the sealing plug 15 and extends into the inside of the shell 1 to be connected with the roller 11.

[0036] A spring 8 is provided between the bayonet 18 and the piston 21 .

[0037] The other parts of this embodiment are the same as those of the above-mentioned embodiment 1, and thus will not be described in detail.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A two-wire current output type liquid level sensor, characterized in that: It comprises a housing (1), an angle-to-current module (6), a transmission mechanism, a connector (20) and a socket (5); the angle-to-current module (6) and the transmission mechanism are located inside the housing (1), and the connector (20) and the socket (5) are located outside the housing (1); The transmission mechanism comprises a steel rope (16) and a first transmission mechanism and a second transmission mechanism which are connected to each other; a piston (21) is slidably provided in the inner hole of the joint (20); one end of the steel rope (16) extends into the inner hole of the joint (20) and is fixedly connected to the piston (21); the other end of the steel rope (16) extends into the interior of the housing (1) and is connected to the first transmission mechanism; The angle-to-current module (6) comprises a first power characteristic enhancement module, a power filter, a first electromagnetic effect enhancement module, a conditioning IC, a magnetic angle sensor, a conversion circuit, a second power characteristic enhancement module, and a second power characteristic enhancement module, which are connected in sequence by electrical signals, wherein the power input end of the first power characteristic enhancement module is connected to the socket (5) by electrical signals, and the signal output end of the second power characteristic enhancement module is connected to a signal line, and the signal line is connected to the negative pole of the socket (5); the magnetic angle sensor is mounted on the second transmission mechanism and is connected to the conversion circuit; the conversion circuit collects the voltage value at both ends of the magnetic resistor in the magnetic angle sensor; the first transmission mechanism comprises a first rotating shaft (10), a roller (11), a first gear (9), a bearing (12), and a volute spring (17); The bearing (12) is fixedly mounted in the housing (1), a first rotating shaft (10) is rotatably mounted on the bearing (12), a first gear (9) and a drum (11) are respectively mounted on the first rotating shaft (10), one end of the steel rope (16) is fixedly wound around the drum (11), and the other end is connected to a joint (20) located outside the housing (1); an inner end of a spiral spring (17) for providing a restoring force to the first rotating shaft (10) is fixedly connected to the first rotating shaft (10), a clockwork box (7) is fixedly mounted in the housing (1), the spiral spring (17) is located in the clockwork box (7), and an outer end of the spiral spring (17) is fixed to an inner wall of the clockwork box (7); The magnetic angle sensor is fixedly mounted in the housing (1); the second rotating shaft (19) is connected to the magnetic angle sensor; and the second gear (4) is arranged on the second rotating shaft (19) and meshes with the first gear (9).

2. A two-wire current output type liquid level sensor according to claim 1, characterized in that: The housing (1) has an open top, an upper cover (2) is mounted on the top opening, and the upper cover (2) has a transparent window (3); a display meter (14) is provided in the housing (1) in an area corresponding to the transparent window (3), the second rotating shaft (19) is coaxial with the center of the display meter (14), and the display meter (14) has a pointer (13) that rotates along with the second rotating shaft (19).

3. A two-wire current output type liquid level sensor according to claim 2, characterized in that: It also comprises a bayonet (18), the outer periphery of the bayonet (18) is provided with a thread, the inner hole of the joint (20) is provided with a corresponding thread, the bayonet (18) and the joint (20) are adjustably connected together through the thread, a sealing plug (15) is provided in the inner hole of the joint (20) for isolating the inside of the shell (1) from the outside, and the other end of the steel rope (16) passes through the sealing plug (15) and extends into the inside of the shell (1) to be connected to the roller (11).

4. A two-wire current output type liquid level sensor according to claim 3, characterized in that: A spring (8) is provided between the bayonet (18) and the piston.

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