Miniature linear displacement sensor

Abstract

A miniature linear displacement sensor disclosed by the present invention comprises a shell, a coil assembly and an iron core, the iron core and the coil assembly are respectively arranged in two independent accommodation spaces of the shell, the iron core can move along the axial direction of the shell, the coil assembly is arranged around the iron core, the coil assembly comprises a coil rack, a layer of primary coil is wound on the coil rack, and the primary coil is wound on the coil rack. A first secondary coil and a second secondary coil are wound on the outer surface of the primary coil and are fully wound, the first secondary coil and the second secondary coil are located at the two ends of the primary coil respectively, a third secondary coil is wound on the first secondary coil, a fourth secondary coil is wound on the second secondary coil, and the primary coil, the first secondary coil and the third secondary coil are wound in the same direction. The winding direction of the second secondary coil and the winding direction of the fourth secondary coil are the same and opposite to the winding direction of the primary coil, the first secondary coil is connected with the fourth secondary coil, and the second secondary coil is connected with the third secondary coil. The miniature linear displacement sensor has the advantages of miniaturization, short stroke, high reliability and high precision.

Description

Technical Field

[0001] The invention belongs to the technical field of displacement sensor design and relates to a micro linear displacement sensor. Background Art

[0002] In the fields of aviation and ships, facing the miniaturization, short stroke, high reliability and high precision requirements of high-reliability rotary direct-drive electro-hydraulic servo valves, traditional linear displacement sensors can no longer meet the design requirements when the sensor installation contour, weight and installation interface are greatly restricted. In order to ensure the performance indicators of the linear displacement sensor, it is urgent to develop a new type of high-reliability miniature linear displacement sensor that can withstand harsh environments, can be installed in a small space, and meet the requirements of flight control systems and high-reliability rotary direct-drive electro-hydraulic servo valves. Summary of the invention

[0003] Purpose of the invention: In order to solve the problem that the existing linear displacement sensors cannot meet the use requirements, the present invention provides a miniature linear displacement sensor. The linear displacement sensor of the present invention is suitable for measuring strokes less than ±0.5mm. Under the condition that the contour, weight and installation interface of the sensor are greatly restricted, the electromagnetic structure of the sensor is optimized and designed, and the stator housing structure, winding structure and mover material are affected by temperature changes under all working conditions and the sensor zero position debugging structure are considered, so that it can withstand harsh environments, be miniaturized, have a short stroke, high reliability and high control accuracy, and can meet the control requirements of high-reliability rotary direct-drive electro-hydraulic servo valves.

[0004] The technical solution of the present invention:

[0005] A miniature linear displacement sensor comprises a shell, a coil assembly, and an iron core. The iron core and the coil assembly are respectively arranged in two independent accommodating spaces of the shell. The iron core can move axially along the shell. The coil assembly is arranged around the iron core. The coil assembly comprises a coil frame. A layer of primary coil is wound on the coil frame. Secondary coil one and secondary coil two are wound on the outer surface of the primary coil and are fully wound. Secondary coil one and secondary coil two are respectively located at two ends of the primary coil. Secondary coil three is wound on secondary coil one, and secondary coil four is wound on secondary coil two. Among them, the primary coil, secondary coil one, and secondary coil three have the same winding direction, the secondary coil two and secondary coil four have the same winding direction and are opposite to the winding direction of the primary coil, the secondary coil one is connected to the secondary coil four, and the secondary coil two is connected to the secondary coil three.

[0006] Preferably, the magnetic conductive cylinder is coaxially arranged outside the coil frame, and the length of the magnetic conductive cylinder is slightly greater than the length of the coil frame.

[0007] Preferably, a polyimide film is adhered to the outer surface of the coil frame.

[0008] Preferably, the iron core is arranged on the connecting rod, and screw plug one and screw plug two are respectively arranged on both sides of the iron core, and screw plug one and screw plug two are threadedly connected to the connecting rod.

[0009] Preferably, magnetic isolation rings are fixed at both ends of the coil frame.

[0010] Preferably, the coil assembly is fixed in the housing 1 by a high thermal conductivity potting glue.

[0011] Preferably, a rear cover is fixed to the shell, and the rear cover can close the accommodating space where the coil assembly is located, and a butterfly spring is arranged between the coil assembly and the rear cover.

[0012] Preferably, the secondary coil 1 and the secondary coil 4 are connected by welding and the welding parts are insulated by a polyimide film.

[0013] Preferably, the outer diameters of screw plug 1 and screw plug 2 are larger than the outer diameter of the core, and the maximum outer diameter of the connecting rod, screw plug 1 and screw plug 2 are all in clearance fit with the shell.

[0014] Preferably, the housing is made of titanium alloy.

[0015] The main advantages of the present invention are: the micro linear displacement sensor has the advantages of miniaturization, short stroke, high reliability and high precision, can be installed in a narrow space and meet the requirements of the flight control system and the high-reliability rotary direct-drive electro-hydraulic servo valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a micro linear displacement sensor of the present invention.

[0017] Figure 2 It is a schematic diagram of the shell structure.

[0018] Figure 3 It is a schematic diagram of the coil assembly structure.

[0019] Figure 4 It is a schematic diagram of the coil frame structure.

[0020] Figure 5 It is a schematic diagram of the winding structure of the coil assembly.

[0021] Figure 6 It is a schematic diagram of the connecting rod assembly structure.

[0022] Figure 7 It is a schematic diagram of the screw plug structure.

[0023] Figure 8 It is a schematic diagram of the sensor zero position size structure.

[0024] In the figure: 1. Shell; 2. Coil assembly; 3. Butterfly spring; 4. Back cover; 5. High thermal conductivity potting glue; 6. Connecting rod assembly; 7. Magnetic isolation ring; 8. Magnetic conductive cylinder; 9. Coil frame; 10. Polyimide film; 11. Secondary coil A; 12. Primary coil; 13. Secondary coil B; 14. Connecting rod; 15. Screw plug 1; 16. Iron core; 17. Screw plug 2. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and its working principle.

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] The features of various aspects of the embodiments of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to fully understand the present invention. However, it is obvious to those skilled in the art that the present invention can also be implemented without these specific details. The following description of the embodiments is only for a better understanding of the present invention by illustrating examples of the present invention. The present invention is not limited to any specific settings and methods provided below, but covers all product structures, any improvements, replacements, etc. of methods covered without departing from the spirit of the present invention.

[0028] In the various drawings and the following description, well-known structures and techniques are not shown to avoid unnecessarily obscuring the present invention.

[0029] A miniature linear displacement sensor comprises a housing 1, a coil assembly 2, a butterfly spring 3 and a rear cover 4.

[0030] like Figure 1 As shown, the coil assembly 2 is arranged in the shell 1, and the coil assembly 2 is compressed by the butterfly spring 3. The rear end of the shell 1 is fixedly connected with a back cover 4. The inside of the shell 1 is filled with high thermal conductivity potting glue 5 to fix the coil assembly 2. A connecting rod assembly 6 is arranged in the central blind hole of the shell 1, and the connecting rod assembly 6 can move linearly in the central blind hole of the shell 1.

[0031] The shell 1 is a thin-walled part made of titanium alloy. It has high strength, light weight and strong corrosion resistance in a limited space. The sensor guide tube and the shell are processed as one body, which improves the coaxiality of the guide tube and the A surface of the shell 1 and the verticality with the B surface, thereby increasing the output accuracy and compressive strength of the sensor.

[0032] The coil assembly 2 includes a magnetic isolation ring 7, a magnetic cylinder 8, a coil frame 9, a polyimide film 10, a secondary coil A1, a secondary coil A2, a primary coil 12, a secondary coil B1, and a secondary coil B2. The magnetic cylinder 8 is installed on the coil frame 9. The magnetic isolation ring 7 is pasted on both ends of the coil frame 9 through organic silicon insulating paint. The length of the magnetic cylinder 8 is greater than the coil frame 9 to ensure that the magnetic isolation ring 7 is in full contact with the magnetic cylinder 8. A complete magnetic circuit is formed by the magnetic cylinder 8, the magnetic isolation ring 7 and the iron core 16, which reduces the influence of sensor leakage and increases the sensor's ability to resist electromagnetic interference.

[0033] The coil frame 9 is a thin-walled part made of titanium alloy, which has high strength and occupies little space in a limited space. The groove of the coil frame 9 is insulated by pasting a polyimide film 10 to increase the insulation reliability of the sensor.

[0034] In the coil assembly 2, when the coil assembly is wound, the primary coil 12 is wound clockwise in the coil frame 9, the secondary coil A1 is wound clockwise on the primary coil 12, the secondary coil A1 is broken after winding, the secondary coil B1 is wound counterclockwise on the primary coil 12, the secondary coil B2 is wound clockwise on the secondary coil A1, and then the secondary coil A2 is wound counterclockwise on the secondary coil B1, and finally the disconnected parts of the secondary coil A1 and the secondary coil A2 are welded and insulated with polyimide film. Through this forward and reverse winding cross winding method, the output sensitivity and linearity of the sensor are improved in a limited space.

[0035] The connecting rod assembly 6 is composed of a connecting rod 14, a screw plug 15, a screw plug 2 17 and an iron core 16. When assembling, the screw plug 15 is assembled first, and then the iron core 16 is installed, and then the screw plug 2 17 is installed. The outer diameter of the screw plug 15 is larger than the outer diameter of the iron core 16 to ensure that the sensor reduces the wear of the iron core 16 during operation and increases the service life of the sensor. When the sensor is zero-position debugged, the positions of the screw plug 15, the screw plug 2 17 and the iron core 16 are adjusted forward and backward to ensure the zero-position dimension L. After the zero-position adjustment is completed, the screw plug 15 and the screw plug 2 17 are tightened to limit the iron core 16, and the screw plug 15, the screw plug 2 17 and the iron core 16 on the connecting rod 14 are fixed by thread locking glue. This structure realizes the adjustable zero position of the sensor and improves the qualified rate of the sensor.

[0036] The middle of the connecting rod 14 is a through hole, and the outer circle of the tail is fully threaded. The iron core 16 is a magnetic conductive element made of soft magnetic alloy material, and its center is a threaded hole. There is a clearance fit between the connecting rod assembly 6 and the housing 1. During operation, oil can be introduced into the housing 1 to form an oil film between the connecting rod assembly 6 and the housing 1, reducing the wear of the connecting rod assembly 6 during operation and improving the service life of the sensor.

[0037] like Figure 7 As shown, screw plug 15 and screw plug 2 17 are made of titanium alloy, and their outer diameters are larger than the outer diameter of the iron core 16, which ensures that the sensor reduces the wear of the iron core 16 during operation and increases the service life of the sensor. The center is a threaded hole, and the outer circle has a plum blossom structure with four notches, which is easy to install and tighten.

Claims

1. A micro linear displacement sensor, characterized in that: The invention comprises a shell (1), a coil assembly (2), and an iron core (16). The iron core (16) and the coil assembly (2) are respectively arranged in two independent accommodating spaces of the shell (1). The iron core (16) can move axially along the shell (1). The coil assembly (2) is arranged around the iron core (16). The coil assembly (2) comprises a coil frame (9). A primary coil (12) is wound on the coil frame (9). A secondary coil 1 (A1) and a secondary coil 2 (B1) are wound on the outer side of the primary coil (12) and are fully wound. The secondary coil 1 (A1) and the secondary coil 2 (B1) are wound on the outer side of the primary coil (12). ) are respectively located at two ends of the primary coil (12), the secondary coil three (B2) is wound on the secondary coil one (A1), and the secondary coil four (A2) is wound on the secondary coil two (B1), wherein the primary coil (12), the secondary coil one (A1), and the secondary coil three (B2) are wound in the same direction, the secondary coil two (B1) and the secondary coil four (A2) are wound in the same direction and opposite to the primary coil (12), the secondary coil one (A1) is connected to the secondary coil four (A2), and the secondary coil two (B1) is connected to the secondary coil three (B2).

2. A micro linear displacement sensor as claimed in claim 1, characterized in that: The magnetic conductive cylinder (8) is coaxially arranged outside the coil frame (9), and the length of the magnetic conductive cylinder (8) is slightly greater than the length of the coil frame (9).

3. A micro linear displacement sensor as claimed in claim 1, characterized in that: A polyimide film (10) is adhered to the outer surface of the coil frame (9).

4. A micro linear displacement sensor as claimed in claim 1, characterized in that: The iron core (16) is arranged on the connecting rod (14), and a first screw plug (15) and a second screw plug (17) are respectively arranged on both sides of the iron core (16), and the first screw plug (15) and the second screw plug (17) are threadedly connected to the connecting rod (14).

5. A micro linear displacement sensor as claimed in claim 1, characterized in that: Magnetic isolation rings (7) are fixed at both ends of the coil frame (9).

6. A micro linear displacement sensor as claimed in claim 1, characterized in that: The coil assembly (2) is fixed in the housing (1) by means of a high thermal conductivity potting glue (5).

7. A micro linear displacement sensor as claimed in claim 1, characterized in that: A rear cover (4) is also fixed on the housing (1), and the rear cover (4) can seal the accommodation space where the coil assembly (2) is located. A butterfly spring (3) is arranged between the coil assembly (2) and the rear cover (4).

8. A micro linear displacement sensor as claimed in claim 1, characterized in that: The secondary coil one (A1) and the secondary coil four (A2) are connected by welding and the welding parts are insulated by a polyimide film.

9. A micro linear displacement sensor as claimed in claim 4, characterized in that: The outer diameters of the first screw plug (15) and the second screw plug (17) are greater than the outer diameter of the iron core (16), and the maximum outer diameter of the connecting rod (14), the first screw plug (15), and the second screw plug (17) are all in clearance fit with the housing (1).

10. A micro linear displacement sensor as claimed in any one of claims 1 to 9, characterized in that: The housing (1) is made of titanium alloy.

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