A LVDT coil structure

Abstract

The invention discloses an LVDT coil structure, comprising a winding tube and a winding frame coaxially sleeved on the outside of the winding tube, insulators are coaxially and symmetrically arranged at two ends of the winding tube, the inner wall of the insulator is connected to the outer wall of the winding tube, and the outer wall is connected to the winding frame, the winding frame, the winding tube and the insulator form an annular cavity, the winding tube is located on the outer wall of the annular cavity to wind a primary coil, the primary coil is symmetrically distributed around the axial center of the winding tube, and the number of turns of the winding coil decreases from the outside to the inside, the secondary coil is wound on the outer surface of the winding frame, and the winding frame, as an insulating layer, can prevent magnetic lines of force from directly passing through the primary coil to reach the secondary coil, can effectively reduce the saturation phenomenon of the magnetic circuit, and at the same time increase the number of coil turns in the nonlinear region at both ends of the primary, so that the magnetic field strength in the nonlinear region at both ends of the sensor is increased, thereby increasing the magnetic flux of the secondary coil, increasing the magnetic induction electromotive force in the nonlinear region of the sensor, and realizing the increase of the linear range of the LVDT sensor.

Description

Technical Field

[0001] The invention relates to the field of sensors, and in particular to an LVDT coil structure. Background Art

[0002] LVDT sensor is a displacement sensor based on the principle of electromagnetic induction. It has the advantages of high precision, high reliability and long life. It is widely used in mechanical, electronic and aviation fields. However, traditional LVDT sensors have the following limitations in range: 1. In order to obtain higher linearity, the range of LVDT sensor is usually only a fraction of the coil length, resulting in a larger sensor installation size; 2. As the displacement increases, the output signal of LVDT will be affected by factors such as noise and temperature, which will reduce the measurement accuracy and linearity of the sensor; 3. The sensor is too large, which will limit the space utilization of the test system. At present, the common solutions to the range problem of LVDT sensors are as follows: (1) Increasing the coil length: mainly increasing the length of the primary and secondary coils, thereby increasing the moving range of the iron core in the coil, thereby increasing the effective stroke. This method will increase the volume of the LVDT sensor and has high space requirements; (2) Increasing the number of turns of the coil at both ends of the secondary coil to increase the effective range of the LVDT sensor. Although this method can increase the induced electromotive force at the ends of the secondary coil of the sensor, the growth trend is difficult to control; (3) The central axis iron core structure is changed to an I-shaped structure. Although this method can increase the linear range of the LVDT sensor, it is difficult to grasp the overall linearity of the LVDT sensor. Summary of the invention

[0003] In view of the above problems, the present invention provides an LVDT coil structure, which has the advantages of small size, long effective range and good stability.

[0004] The technical solution of the present invention is:

[0005] A LVDT coil structure comprises a winding tube and a winding frame coaxially sleeved on the outside of the winding tube, insulators are coaxially and symmetrically arranged at both ends of the winding tube, the inner wall of the insulator is connected to the outer wall of the winding tube, the outer wall of the insulator is connected to the winding frame, the winding frame, the winding tube and the insulator form an annular cavity, the winding tube is located on the outer wall of the annular cavity to wind a primary coil, the primary coil is symmetrically distributed around the axial center of the winding tube, and the number of turns of the wound coil decreases from the outside to the inside, the secondary coil is wound on the outer surface of the winding frame, linear end covers are symmetrically arranged at both ends of the annular cavity along the axial direction of the winding tube, and the linear end covers are coaxially sleeved on the winding tube.

[0006] The outer diameter of the linear end cap is the same as the outer diameter of the winding skeleton.

[0007] An insulating tape is arranged between the primary coil and the bobbin, and an insulating tape is arranged on the outer surface of the primary coil.

[0008] The linear end cover arranged at one end of the winding tube is provided with a gasket at one end facing the winding skeleton.

[0009] The linear end cap is a linear magnet.

[0010] The beneficial effects of the present invention are:

[0011] This technology increases the number of coil turns in the nonlinear region at both ends of the primary, which will increase the magnetic field strength in the nonlinear region at both ends of the sensor, thereby increasing the magnetic flux of the secondary coil, and finally increasing the magnetic induced electromotive force in the nonlinear region of the sensor, thereby increasing the linear range of the LVDT sensor.

[0012] Adding a winding frame between the primary and secondary coils as an insulation layer can improve the stability of the LVDT coil structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the overall structure of an LVDT coil structure according to an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of a primary coil structure of an LVDT coil structure according to an embodiment of the present invention;

[0015] Figure 3 is a schematic diagram of a commonly used LVDT coil structure according to an embodiment of the present invention;

[0016] Figure 4 is a potential displacement characteristic diagram of a sensor corresponding to an LVDT coil structure described in an embodiment of the present invention;

[0017] Figure 5 It is a potential displacement characteristic diagram of a sensor corresponding to another LVDT coil structure described in an embodiment of the present invention.

[0018] Description of reference numerals:

[0019] 1 is a winding bobbin, 2 is a winding frame, 3 is an insulator, 4 is a primary coil, 5 is a secondary coil, 6 is a linear end cover, 7 is an insulating tape, and 8 is a gasket. DETAILED DESCRIPTION

[0020] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0021] Example

[0022] like Figure 1-Figure 2As shown, an LVDT coil structure includes a winding tube 1 and a winding frame 2 coaxially sleeved on the outside of the winding tube 1, insulators 3 are coaxially and symmetrically arranged at both ends of the winding tube 1, the inner wall of the insulator 3 is connected to the outer wall of the winding tube 1, and the outer wall of the insulator 3 is connected to the winding frame 2, the winding frame 2, the winding tube 1 and the insulator 3 form an annular cavity, the winding tube 1 is located on the outer wall of the annular cavity to wind a primary coil 4, the primary coil 4 is symmetrically distributed around the axial center of the winding tube 1, and the number of turns of the wound coil decreases from the outside to the inside, the secondary coil 5 is wound on the outer surface of the winding frame 2, and linear end covers 6 are symmetrically arranged at both ends of the annular cavity along the axial direction of the winding tube 1, and the linear end covers 6 are coaxially sleeved on the winding tube 1.

[0023] The working principle of the above technical solution is as follows:

[0024] The winding skeleton 2 acts as an insulating layer, which can prevent the magnetic lines of force from directly passing through the primary coil 4 to the secondary coil 5, which can effectively reduce the saturation phenomenon of the magnetic circuit, increase the linearity and linear range of the LVDT sensor, and at the same time increase the number of coil turns in the non-linear region at both ends of the primary, which will increase the magnetic field strength in the non-linear region at both ends of the sensor, thereby increasing the magnetic flux of the secondary coil, and finally increasing the magnetic induced electromotive force in the non-linear region of the sensor, thereby increasing the linear range of the LVDT sensor.

[0025] The outer diameter of the linear end cover 6 is the same as the outer diameter of the winding frame 2, which can reduce the volume of the equipment and facilitate assembly.

[0026] An insulating tape 7 is arranged between the primary coil 4 and the bobbin 1 , and an insulating tape 7 is arranged on the outer surface of the primary coil 4 , which can further improve the stability of the coil structure.

[0027] A linear end cap 6 arranged at one end of the winding tube 1 is provided with a gasket 8 facing one end of the winding frame 2 to achieve an insulating effect. The linear end cap 6 is a linear magnet used to provide a closed magnetic circuit, reduce external interference with the internal magnetic field of the sensor, and increase the magnetic field strength at both ends.

[0028] like Figure 3 As shown in the figure, a commonly used LVDT coil has linear end caps 6 and gaskets 8 symmetrically arranged at both ends of the winding tube 1 in the axial direction, and the linear end caps 6 and gaskets 8 are coaxially sleeved on the winding tube 1; the primary coil 4 is wound on the winding tube 1, and the secondary coil 5 is wound on the primary coil 4; and an insulating tape 7 is arranged between the primary coil 4 and the winding tube 1, and an insulating tape 7 is arranged on the surface of the primary coil. The test results are shown in Table 1 below, and the potential displacement characteristic diagram is shown in Figure 4 shown.

[0029]

[0030] Depend on Figure 4It can be seen that the area between ±6mm is the linear area, and the area between 6mm~10mm and -6mm~-10mm is the nonlinear area.

[0031] The data in Table 1 are calculated by the least square method and the linearity of ±6mm is 0.50%; the linearity of ±10mm is 3.17%.

[0032] This technology can also separate the primary and secondary coils, that is, the secondary coil 5 is wound on the winding frame 2, and the nonlinear regions at both ends of the primary coil 4 are wound in a step-by-step manner, with the number of coil turns decreasing from the outside to the inside. The specific test results are shown in Table 2, and the potential displacement characteristic diagram is shown in Figure 5 shown.

[0033]

[0034] The data in Table 2 are calculated by the least square method and the linearity of ±10 mm is 0.31%.

[0035] Compared with the above LVDT sensor: the linear range of the LVDT sensor output of the present application is increased by 4 mm, and the linearity is increased from 0.50% to 0.31%.

[0036] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An LVDT coil structure, characterized in that: It includes a winding tube and a winding frame coaxially sleeved on the outside of the winding tube, insulators are coaxially and symmetrically arranged at both ends of the winding tube, the inner wall of the insulator is connected to the outer wall of the winding tube, the outer wall of the insulator is connected to the winding frame, the winding frame, the winding tube and the insulator form an annular cavity, the winding tube is located on the outer wall of the annular cavity to wind a primary coil, the primary coil is symmetrically distributed around the axial center of the winding tube, and the number of turns of the wound coil decreases from the outside to the inside, the secondary coil is wound on the outer surface of the winding frame, linear end covers are symmetrically arranged at both ends of the annular cavity along the axial direction of the winding tube, and the linear end covers are coaxially sleeved on the winding tube.

2. The LVDT coil structure according to claim 1, characterized in that: The outer diameter of the linear end cap is the same as the outer diameter of the winding skeleton.

3. The LVDT coil structure according to claim 1, characterized in that: An insulating tape is arranged between the primary coil and the bobbin, and an insulating tape is arranged on the outer surface of the primary coil.

4. The LVDT coil structure according to claim 1, characterized in that: The linear end cover arranged at one end of the winding tube is provided with a gasket at one end facing the winding skeleton.

5. The LVDT coil structure according to claim 1, characterized in that: The linear end cap is a linear magnet.

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