Differential transformer type linear displacement sensor with outer layer equal difference distributed coil

Abstract

The invention provides a differential transformer type linear displacement sensor with an outer layer equal difference distributed coil, and relates to the field of linear displacement sensors. Comprising a magnetic conductive cylinder, a coil framework arranged in the magnetic conductive cylinder, a primary winding arranged on the coil framework, two stepped secondary windings symmetrically arranged on the primary winding along the center line of the magnetic conductive cylinder, and two equidifferent distributed windings symmetrically arranged on the stepped secondary windings along the center line of the magnetic conductive cylinder, the differential transformer type linear displacement sensor has the advantages that the output precision of the differential transformer type linear displacement sensor is improved, the application range of the differential transformer type linear displacement sensor is expanded, the reliability of the differential transformer type linear displacement sensor is improved, the reliability of the differential transformer type linear displacement sensor is improved, and the reliability of the differential transformer type linear displacement sensor is improved. The space occupied by the coil assembly is reduced, the feasibility of the automatic winding process of the differential transformer type linear displacement sensor is endowed, and the production efficiency of the differential transformer type linear displacement sensor is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of linear displacement sensors, in particular to a differential transformer type linear displacement sensor with an outer equidistant distributed coil. Background Art

[0002] The differential transformer linear displacement sensor is a linear position sensor based on the principle of electromagnetic induction. The linear displacement sensor uses the regular change of the induced voltage of the coil group caused by the relative change of the position of the magnetically conductive mover to realize the direct correlation between the output voltage signal and the mover position. Compared with the resistive, capacitive, Hall and magnetostrictive linear displacement sensors, the differential transformer linear displacement sensor has the advantages of simple structure, reliable operation, high precision, good linearity, frictionless contact, long life, etc. At the same time, it has high pressure resistance, anti-pollution and anti-electromagnetic interference characteristics. It is widely used in high-precision linear position measurement scenarios such as nozzles, oil needles and throttle levers, electro-hydraulic servo valves inside aircraft engines. The differential transformer linear displacement sensor can be classified according to the relative position relationship between the primary excitation coil and the secondary output coil. The most common ones are two-stage and three-stage coil structures. In addition, it can be expanded to a multi-stage structure according to the needs of actual application scenarios.

[0003] Existing two-stage differential transformer linear displacement sensors often require compensation coils to adjust the output signal and linearity of the sensor. Adding the compensation coil not only increases the outer diameter and volume of the coil, but also causes the application of automated winding technology in the production process of the differential transformer linear displacement sensor, resulting in large volume of the existing differential transformer linear displacement sensor coil assembly, long manufacturing time, low production efficiency, and low one-time adjustment qualification rate. The above shortcomings limit the application of differential transformer linear displacement sensors in high-precision position feedback scenarios.

[0004] Therefore, it is necessary to provide a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils, so as to improve the output accuracy of the differential transformer type linear displacement sensor, expand the scope of use of the differential transformer type linear displacement sensor, reduce the space occupied by the coil assembly, and make the automatic winding process of the differential transformer type linear displacement sensor feasible, thereby greatly improving the production efficiency of the differential transformer type linear displacement sensor. Summary of the invention

[0005] The present invention provides a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils, comprising a magnetic cylinder, a coil frame arranged in the magnetic cylinder, a primary winding arranged on the coil frame, two stepped secondary windings symmetrically arranged on the primary winding along the center line of the magnetic cylinder, and two equidistant distributed windings symmetrically arranged on the stepped secondary winding along the center line of the magnetic cylinder, wherein the coil frame is placed coaxially with the magnetic cylinder, an iron core is further arranged in the coil frame, and the iron core is used to follow the component to be measured to reciprocate in a straight line along the axis direction of the magnetic cylinder.

[0006] Furthermore, the stepped secondary winding includes a first secondary winding, a second secondary winding arranged on the first secondary winding, and a third secondary winding arranged on the second secondary winding, the equidistant distributed winding includes a first winding and a second winding, the third secondary winding is provided with a first winding, and the second winding is provided on one end of the first winding close to the midline of the magnetic conductive cylinder.

[0007] Furthermore, the stepped secondary winding includes a first secondary winding, a second secondary winding arranged on the first secondary winding, and a third secondary winding arranged on the second secondary winding, and the equidistant distributed winding includes a first winding and a second winding, the second secondary winding is provided with a first winding at one end close to the center line of the magnetic cylinder, and the first winding is provided with the second winding at one end close to the center line of the magnetic cylinder.

[0008] Furthermore, at least one of the arrangement position, coil spacing distance, number of turns and wiring position of the first winding and the second winding is determined according to output signal indicator requirements.

[0009] Furthermore, the connection mode of the equidistant distributed winding may be any one of a clockwise forward connection, a counterclockwise forward connection, a clockwise interchange connection and a counterclockwise interchange connection.

[0010] Furthermore, the output signal index at least includes an output signal linearity index, a sensitivity index and an output voltage index.

[0011] Furthermore, a coil spacing distance of the first winding is greater than a coil spacing distance of the second winding.

[0012] Furthermore, the number of turns of the first winding is greater than the number of turns of the second winding.

[0013] Furthermore, the primary winding, the stepped secondary winding and the equidistant distributed winding are all wound by an automatic winding machine.

[0014] Further, the length of the axis of the coil frame covered by the first winding and the length of the axis of the coil frame covered by the second winding are less than or equal to half of the length of the axis covered by the magnetic conductive cylinder covered by the primary winding.

[0015] Compared with the prior art, the differential transformer type linear displacement sensor with outer equidistant distributed coils provided by the present invention has at least the following beneficial effects: No additional compensation coil is required, and the radial volume is effectively reduced. The primary winding, the stepped secondary winding and the equidistant distributed winding in the differential transformer type linear displacement sensor with an outer equidistant distributed coil all have regular and regular appearance shapes, and can be automatically wound by an automatic winding machine. While being able to flexibly meet different output signal requirements, the output performance and production efficiency of the differential transformer type linear displacement sensor can be significantly improved, and the problems of large coil component volume, long manufacturing time, low production efficiency, low one-time adjustment qualification rate and poor consistency in the differential transformer type linear displacement sensor are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein: Figure 1 It is a structural schematic diagram of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of this specification; Figure 2 is a cross-sectional view of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of the present specification; Figure 3 is a cross-sectional view of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of the present specification; Figure 4 is a schematic diagram of clockwise forward connection according to some embodiments of this specification; Figure 5 is a schematic diagram of a counterclockwise forward connection according to some embodiments of this specification; Figure 6 is a schematic diagram of clockwise interchangeable connection according to some embodiments of this specification; Figure 7 is a schematic diagram of counterclockwise interchangeable connection according to some embodiments of this specification; Figure 8 is a schematic diagram of placing different areas of the secondary coil in the axial direction of the differential transformer type linear displacement sensor according to some embodiments of the present specification; Fig. 9 is a schematic diagram of the effect of placing windings at different positions on the output voltage according to some embodiments of this specification; Fig.10 It is a schematic diagram of an output signal curve and its linearity and sensitivity distribution of an existing differential transformer type linear displacement sensor according to some embodiments of this specification; Fig.11 It is a schematic diagram of the output signal curve and its linearity and sensitivity distribution of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of this specification.

[0017] In the figure, 1, primary winding; 2, stepped secondary winding; 21, first secondary winding; 22, second secondary winding; 23, third secondary winding; 3, equidistant distributed winding; 31, first winding; 32, second winding; 4, coil frame; 5, iron core; 6, magnetic tube. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0019] Figure 1 is a schematic structural diagram of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of this specification, Figure 2 is a cross-sectional view of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of this specification, such as Figure 1 and Figure 2 As shown, the differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils includes a magnetic cylinder 6, a coil frame 4 arranged in the magnetic cylinder 6, a primary winding 1 arranged on the coil frame 4, two stepped secondary windings 2 symmetrically arranged on the primary winding 1 along the center line of the magnetic cylinder 6, and two equidistant distributed windings 3 symmetrically arranged on the stepped secondary winding 2 along the center line of the magnetic cylinder 6, wherein the coil frame 4 is coaxially placed with the magnetic cylinder 6, and an iron core 5 is further arranged in the coil frame 4. The iron core 5 is in a cylindrical space surrounded by the coil frame 4, and the iron core 5 is used to follow the component to be measured to reciprocate in a straight line along the axis direction of the magnetic cylinder 6. The equidistant distributed winding 3 is located on the outermost surface of the coil of the stepped secondary winding 2, and the overall structure of the sensor is compact, and no additional compensation coil is required.

[0020] Specifically, the internal space of the magnetic tube 6 can be cylindrical. The primary winding 1 is tightly wound on the surface of the coil skeleton 4, and the overall appearance is annular, and any cross section along the radial direction of the magnetic tube 6 is rectangular. The outer layer of equidistant distributed coil is wound on the outer surface of the primary winding 1, and the overall appearance is annular with unequal thickness along the axial direction of the magnetic tube 6, and any cross section along the radial direction of the magnetic tube 6 is stepped. The equidistant distributed winding 3 is wound on the outer surface of the stepped secondary winding, and the overall appearance is a discrete annular along the axial direction of the magnetic tube 6, and any cross section along the radial direction is a dispersed plurality of single-turn circles. The primary winding 1, the stepped secondary winding 2 and the equidistant distributed winding 3 are all made of round enameled wire. The coil skeleton 4 is a non-magnetic metal (for example, titanium alloy), and the magnetic tube 6 and the iron core 5 are magnetic metals.

[0021] like Figure 2 As shown, in some embodiments, the stepped secondary winding 2 includes a first secondary winding 21, a second secondary winding 22 arranged on the first secondary winding 21, and a third secondary winding 23 arranged on the second secondary winding 22, the equidistant distributed winding 3 includes a first winding 31 and a second winding 32, the third secondary winding 23 is provided with the first winding 31, and the first winding 31 is provided with the second winding 32 at one end of the center line of the magnetic tube 6.

[0022] Figure 3 is a cross-sectional view of a differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils according to some embodiments of this specification, such as Figure 3 As shown, in some embodiments, the stepped secondary winding 2 includes a first secondary winding 21, a second secondary winding 22 arranged on the first secondary winding 21, and a third secondary winding 23 arranged on the second secondary winding 22, and the equidistant distributed winding 3 includes a first winding 31 and a second winding 32, the second secondary winding 22 is provided with the first winding 31 at one end close to the center line of the magnetic cylinder 6, and the first winding 31 is provided with the second winding 32 at one end close to the center line of the magnetic cylinder 6, wherein the coil spacing distance of the first winding 31 is greater than the coil spacing distance of the second winding 32. The number of turns of the first winding 31 is greater than the number of turns of the second winding 32.

[0023] In some embodiments, at least one of the arrangement position, coil spacing, number of turns and wiring position of the first winding 31 and the second winding 32 is determined according to output signal index requirements, wherein the output signal index at least includes output signal linearity index, sensitivity index and output voltage index.

[0024] Figure 4 According to the schematic diagram of clockwise positive connection shown in some embodiments of this specification, Figure 5According to the schematic diagram of counterclockwise forward connection shown in some embodiments of this specification, Figure 6 According to the schematic diagram of clockwise interchange connection shown in some embodiments of this specification, Figure 7 According to the schematic diagram of counterclockwise interchange connection shown in some embodiments of this specification, Figure 4-Figure 7 As shown, the connection mode of the equidistant distributed winding 3 can be any one of clockwise positive connection, counterclockwise positive connection, clockwise interchange connection and counterclockwise interchange connection.

[0025] Specifically, the secondary winding output of the linear displacement sensor is output according to the A phase and the B phase, and the equidistant distribution coil is also divided into the A phase and the B phase, and then connected in series to the original A phase and the B phase. Figure 4 As shown, the left side is the secondary winding phase A, and the right side is the secondary winding phase B. In the clockwise positive connection method, the stepped secondary winding (2-1) on the left is the A phase, the stepped secondary winding (2-2) on the right is the B phase, the equidistant distributed winding (3-1) on the left is the A phase, and the equidistant distributed winding (3-2) on the right is the B phase, and the winding direction of the equidistant distributed winding is consistent with the winding direction of the stepped secondary winding. Figure 5 As shown, in the counterclockwise forward connection mode, the stepped secondary winding (2-1) on the left is phase A, the stepped secondary winding (2-2) on the right is phase B, the equidistant distributed winding (3-1) on the left is phase B, the equidistant distributed winding (3-2) on the right is phase A, and the winding direction of the equidistant distributed winding is consistent with that of the stepped secondary winding. Figure 6 As shown, in the clockwise interchange connection mode, the stepped secondary winding (2-1) on the left is phase A, the stepped secondary winding (2-2) on the right is phase B, the equidistant distributed winding (3-1) on the left is phase A, the equidistant distributed winding (3-2) on the right is phase B, and the winding direction of the equidistant distributed winding is opposite to that of the stepped secondary winding. Figure 7 As shown, in the counterclockwise interchange connection mode, the stepped secondary winding (2-1) on the left is the A phase, the stepped secondary winding (2-2) on the right is the B phase, the equidistant distributed winding (3-1) on the left is the B phase, the equidistant distributed winding (3-2) on the right is the A phase, and the winding direction of the equidistant distributed winding is opposite to that of the stepped secondary winding.

[0026] In some embodiments, the length of the axis of the coil bobbin 4 covered by the first winding 31 and the length of the axis of the coil bobbin 4 covered by the second winding 32 are less than or equal to half the length of the axis of the coil bobbin 4 covered by the primary winding 1 .

[0027] In some embodiments, the primary winding 1 , the stepped secondary winding 2 and the equidistant distributed winding 3 are all wound using an automatic winding machine.

[0028] When the differential transformer type linear displacement sensor has output signal sensitivity and linearity deviation, the prior art uses a centralized compensation winding to adjust the output signal, for example, a common compensation coil is set in the middle area of ​​the differential transformer type linear displacement sensor or a compensation winding is set in a specific area of ​​the differential transformer type linear displacement sensor. The thickness of the coil of the compensation winding is relatively large, which greatly increases the radial length of the secondary winding and the overall volume of the coil assembly of the differential transformer type linear displacement sensor. At the same time, the position accuracy of the compensation winding is high, and the position offset caused by human error during the winding process will destroy the compensation effect of the compensation coil, resulting in the degradation of the output signal accuracy.

[0029] Due to the uneven distribution of the internal magnetic field of the differential transformer linear displacement sensor, placing the secondary coil in different areas along the axis of the differential transformer linear displacement sensor will produce different output signals. The magnitude and bending mode of the output difference voltage and sum voltage will change significantly with the position, such as Figure 8 and 9 shown.

[0030] The differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils described in this specification combines single-turn coils with different bending characteristics by using the principle of refined superposition to offset the bending phenomenon of the output signal and achieve a high linearity output effect. At the same time, the differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils is provided with an equidistant distributed winding 3, which is equivalent to adding a variable number of secondary coils in multiple regions at the same time. By changing the spacing distance of the equidistant distributed secondary windings, the position and number of turns of the additional coils can be changed, and the overall radial size of the differential transformer type linear displacement sensor is significantly reduced.

[0031] Therefore, the differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils recorded in this specification can adjust the output signal sensitivity and linearity of the differential transformer type linear displacement sensor without a large centralized compensation coil. It is very flexible in practical application and can be applied to structures of different sizes of stepped secondary windings 2 and different external dimensions of differential transformer type linear displacement sensors.

[0032] According to the test, the output signal curve of the existing differential transformer linear displacement sensor and its linearity and sensitivity distribution are as follows: Fig.10 As shown in the figure, the output signal curve of the differential transformer linear displacement sensor with an outer layer of equidistant distributed coils and its linearity and sensitivity distribution are shown in Fig.11 As shown, by comparison, it can be seen that the differential transformer type linear displacement sensor with outer equidistant distributed coils recorded in this specification improves the quality of the output signal.

[0033] In summary, the differential transformer type linear displacement sensor with an outer layer of equidistant distributed coils does not require an additional centralized compensation coil, and the radial volume is effectively reduced. All winding components in the differential transformer type linear displacement sensor have regular and regular appearance shapes, and can be automatically wound using an automatic winding machine. While being able to flexibly meet different output signal requirements, it can significantly improve the output performance and production efficiency of the differential transformer type linear displacement sensor, and effectively improve the existing differential transformer type linear displacement sensor. The problems of large coil component volume, long manufacturing time, low production efficiency, low one-time adjustment qualification rate, and poor consistency have been solved.

[0034] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A differential transformer type linear displacement sensor having an outer layer of equidistant distributed coils, characterized in that: It includes a magnetic cylinder, a coil frame arranged in the magnetic cylinder, a primary winding arranged on the coil frame, two stepped secondary windings symmetrically arranged on the primary winding along the center line of the magnetic cylinder, and two equidistant distributed windings symmetrically arranged on the stepped secondary winding along the center line of the magnetic cylinder, wherein the coil frame is placed coaxially with the magnetic cylinder, and an iron core is also arranged in the coil frame, and the iron core is used to follow the component to be tested and move back and forth in a straight line along the axial direction of the magnetic cylinder.

2. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 1, characterized in that: The stepped secondary winding includes a first secondary winding, a second secondary winding arranged on the first secondary winding, and a third secondary winding arranged on the second secondary winding. The equidistant distributed winding includes a first winding and a second winding. The third secondary winding is provided with a first winding, and the second winding is provided on one end of the first winding close to the midline of the magnetic conductive cylinder.

3. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 1, characterized in that: The stepped secondary winding includes a first secondary winding, a second secondary winding arranged on the first secondary winding, and a third secondary winding arranged on the second secondary winding. The equidistant distributed winding includes a first winding and a second winding. The first winding is arranged on one end of the second secondary winding close to the center line of the magnetic cylinder, and the second winding is arranged on one end of the first winding close to the center line of the magnetic cylinder.

4. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 2 or 3, characterized in that: At least one of the arrangement position, coil spacing distance, number of turns and wiring position of the first winding and the second winding is determined according to output signal indicator requirements.

5. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 4, characterized in that: The connection mode of the equidistant distributed winding can be any one of clockwise positive connection, counterclockwise positive connection, clockwise interchange connection and counterclockwise interchange connection.

6. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 4, characterized in that: The output signal index at least includes an output signal linearity index, a sensitivity index and an output voltage index.

7. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 2 or 3, characterized in that: The coil spacing distance of the first winding is greater than the coil spacing distance of the second winding.

8. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 2 or 3, characterized in that: The number of turns of the first winding is greater than the number of turns of the second winding.

9. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to any one of claims 1 to 3, characterized in that: The primary winding, the stepped secondary winding and the equidistant distributed winding are all wound by an automatic winding machine.

10. The differential transformer type linear displacement sensor with outer equidistant distributed coils according to claim 2 or 3, characterized in that: The length of the axis of the coil frame covered by the first winding and the length of the axis of the coil frame covered by the second winding are less than or equal to half of the length of the axis of the magnetic conductive cylinder covered by the primary winding.

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