Wide-range three-pole type rotary differential transformer

Abstract

The invention relates to the technical field of measurement which is not specially used for specific variables, in particular to a wide-range three-pole type rotary differential transformer which comprises a three-pole stator lamination layer and a matched rotor lamination layer. The stator lamination is formed by laminating a plurality of soft magnetic alloy laminations, and the pole shoe covering angle of each tooth is 106 degrees; the rotor lamination is provided with a 120-degree fan-shaped magnetic conductive surface, and the requirement for + / -53-degree effective stroke is met. Through the innovative three-pole design and the optimized material technology, the measurement range is remarkably expanded, and meanwhile high linearity and stability are kept. Test data show that the output voltage and the angle of the structure in the range of + / -53 degrees are in a highly linear relationship, and the structure is suitable for wide-angle measurement scenes such as aircraft undercarriages.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology not dedicated to specific variables, and in particular to a large-range three-pole rotary differential transformer. Background Art

[0002] A rotary differential transformer (RVDT) is an electromechanical product that converts mechanical angular displacement signals into proportional AC voltage output signals and is widely used in fields such as industrial automation and aerospace. Traditional RVDT designs are often based on motor structures. To achieve a uniform and symmetrical excitation magnetic field, the pole shoes often adopt an even-numbered pole design, such as four-pole, eight-pole, and sixteen-pole. Among them, the four-pole structure is widely used due to its uniform magnetic field distribution and high output voltage amplitude. In a four-pole RVDT, four slots are evenly distributed in the inner hole of the stator lamination, and the pole shoe coverage angle of each tooth is approximately 76°. The rotor lamination is designed with two symmetrical 90° fan-shaped magnetic conductive surfaces, so that the coupling angle with the stator pole shoe is 38° when the rotor rotates clockwise and counterclockwise, thus achieving an effective measurement range of ±38°.

[0003] However, the even-pole design significantly limits the maximum measurement angle of the RVDT and cannot meet the needs of larger angle measurements. This is especially true in application scenarios such as aircraft landing gear and doors that require large-angle actuation. The limitations of traditional RVDT are particularly prominent. Summary of the Invention

[0004] Through research, the inventors discovered that, with advances in electronic technology, high-voltage amplitude output is no longer a technical challenge. Instead, expanding the RVDT's measurement range has become a pressing technical challenge. Due to structural limitations, the maximum effective range of existing four-pole RVDTs is fixed at ±38°, making simple optimization difficult to achieve. While increasing the number of poles can improve magnetic field uniformity, it further narrows the measurement range, failing to fundamentally address the problem. Therefore, breaking away from the traditional even-pole design paradigm and exploring new structural forms to achieve a wider measurement range has become a key direction for the development of RVDT technology.

[0005] The purpose of the present invention is to provide a large-range three-pole rotary differential transformer, which solves the technical problem of limited range of existing rotary differential transformers through the construction of three-pole stator laminations and rotor laminations; while maintaining high linearity and stability.

[0006] The present invention provides a large-range three-pole rotary differential transformer, comprising a stator lamination and a rotor lamination; wherein the stator lamination is formed by pressing stator laminations to form a three-pole structure, and the angle covered by the pole shoe of each tooth is 106°; the rotor lamination is formed by pressing rotor laminations, and the rotor lamination has a 120° sector-shaped magnetic conductive surface.

[0007] In some embodiments, the stator laminations and the rotor laminations are made of soft magnetic alloy material.

[0008] In some embodiments, the stator laminations and the rotor laminations have a thickness of 0.2 mm to 1 mm.

[0009] In some embodiments, the stator laminations and the rotor laminations have a saturation magnetic induction intensity greater than or equal to 0.75 T, a coercive force less than or equal to 1.6 A / m, and a maximum magnetic permeability greater than or equal to 225 mH / m.

[0010] In some embodiments, the stator laminations have a thickness of 5.5 mm and the rotor laminations have a thickness of 7.5 mm.

[0011] In some embodiments, an electrical winding is further included, wherein the electrical winding includes an excitation winding, an output winding A coil, and an output winding B coil.

[0012] In some embodiments, three slots are evenly opened in the inner hole of the stator lamination, the angle covered by the pole shoe of each tooth is 106°, and the coupling angle between the 120° sector-shaped magnetic conductive surface and the pole shoe of the stator lamination is 53°.

[0013] In some embodiments, the rotor lamination has a salient pole structure, and the salient pole structure realizes detection of the rotor rotation angle by coupling with the stator lamination.

[0014] In some embodiments, the output voltage of the output winding A coil and the output winding B coil is proportional to the rotor rotation angle.

[0015] Compared with the prior art, the present invention has the following beneficial effects: by designing the stator lamination into a three-pole structure and combining it with the working principle of the rotary differential transformer, the effective measurement range of the rotary differential transformer is increased from the traditional ±38° to ±53°, significantly improving the applicable environment of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural diagram of a large-range three-pole rotary differential transformer of the present invention;

[0018] Figure 2 It is a schematic diagram of the three-pole stator structure of the large-range three-pole rotary differential transformer of the present invention;

[0019] Figure 3 Schematic diagram of the stator lamination of the large-range three-pole rotary differential transformer of the present invention;

[0020] Figure 4 Schematic diagram of the rotor laminations of the large-range three-pole rotary differential transformer of the present invention;

[0021] Figure 5 Schematic diagram of the rotor lamination of the large-range three-pole rotary differential transformer of the present invention;

[0022] Figure 6 This is a working principle diagram of the large-range three-pole rotary differential transformer of the present invention;

[0023] Figure 7 It is an output characteristic curve diagram of the large-range three-pole rotary differential transformer of the present invention. DETAILED DESCRIPTION

[0024] The following is a combination of the embodiments of the present invention Figure 1-7 The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Example

[0026] First, the stator and rotor laminations need to be prepared.

[0027] The stator lamination is formed by pressing together multiple stator laminations. Each stator lamination is made of a soft magnetic alloy, preferably the iron-nickel soft magnetic alloy 1J79 or 1J50. The stator lamination is circular with three evenly spaced notches, and the pole shoe of each tooth covers an angle of 106°. Before pressing together, the stator laminations are heat treated to optimize their magnetic properties. The performance after heat treatment should meet the requirements of a saturation magnetic induction intensity of not less than 0.75T, a coercive force of not more than 1.6A / m, and a maximum magnetic permeability of not less than 225mH / m. After heat treatment, the stator laminations are sprayed with adhesive and pressed together using a tooling to form a stator lamination of a certain thickness, typically 5.5mm. The pressed stator laminations are then dried and shaped in a drying oven at 150°C for 2 hours to ensure the lamination's stability and mechanical strength. The stator lamination is finally finished to the designed dimensions.

[0028] The preparation process of the rotor lamination is similar to that of the stator lamination. The rotor lamination is formed by pressing together multiple rotor laminations, which are also made of soft magnetic alloy materials, preferably iron-nickel soft magnetic alloy 1J79 or 1J50. The rotor lamination is fan-shaped and has a 120° fan-shaped magnetic conductive surface 8. After processing, the rotor laminations need to undergo the same heat treatment process to optimize their magnetic properties, and then sprayed with adhesive and pressed into a rotor lamination of a certain thickness, usually 7.5mm. The pressed rotor lamination also needs to be kept in a drying oven at 150°C for 2 hours to dry and shape it, and finally fine-machined to the designed size to complete the preparation.

[0029] After the stator and rotor laminations are prepared, the electrical windings are designed and arranged. The excitation winding is placed on the 23-pole shoe, the output winding A coil is placed on the 12-pole shoe, and the output winding B coil is wound in the opposite direction on the 13-pole shoe. This arrangement enables differential output of the output winding A coil and the output winding B coil, with the output voltage proportional to the rotor rotation angle. The salient pole structure on the rotor lamination, coupled with the stator lamination, enables precise detection of the rotor rotation angle. When the rotor lamination rotates clockwise or counterclockwise, the 120° sector-shaped magnetic conductive surface on the rotor lamination and the stator lamination pole shoe have a coupling angle of 53°, for a total of 106°, thus achieving an effective measurement range of ±53°.

[0030] In order to verify the performance of the present invention, the output voltage values ​​at different angles were tested, and the test data are as follows:

[0031] The positive angle test results show that:

[0032] When the test angle is 0°, the output voltage is 0.015V;

[0033] When the test angle is 6°, the output voltage is 0.380V;

[0034] When the test angle is 12°, the output voltage is 0.773V;

[0035] When the test angle is 18°, the output voltage is 1.168V;

[0036] When the test angle is 24°, the output voltage is 1.551V;

[0037] When the test angle is 30°, the output voltage is 1.943V;

[0038] When the test angle is 36°, the output voltage is 2.337V;

[0039] When the test angle is 42°, the output voltage is 2.725V;

[0040] When the test angle is 48°, the output voltage is 3.120V;

[0041] When the test angle is 53°, the output voltage is 3.458V.

[0042] The negative angle test results show that:

[0043] When the test angle is -6°, the output voltage is 0.404V;

[0044] When the test angle is -12°, the output voltage is 0.792V;

[0045] When the test angle is -18°, the output voltage is 1.186V;

[0046] When the test angle is -24°, the output voltage is 1.573V;

[0047] When the test angle is -30°, the output voltage is 1.965V;

[0048] When the test angle is -36°, the output voltage is 2.360V;

[0049] When the test angle is -42°, the output voltage is 2.746V;

[0050] When the test angle is -48°, the output voltage is 3.135V;

[0051] When the test angle is -53°, the output voltage is 3.460V.

[0052] That is, the specific test data of the present invention are shown in the following table:

[0053] Table 3-pole RVDT test data

[0054] Test angle / ° 0 6 12 18 24 30 36 42 48 53 Output voltage / V 0.015 0.380 0.773 1.168 1.551 1.943 2.337 2.725 3.120 3.458 Test angle / ° / -6 -12 -18 -24 -30 -36 -42 -48 -53 Output voltage / V / 0.404 0.792 1.186 1.573 1.965 2.360 2.746 3.135 3.460

[0055] It can be seen from the above test data that the three-pole RVDT provided by the present invention has good linearity within the range of ±53°, and the output voltage is highly linearly related to the test angle.

[0056] The practical operating principle of this invention is based on the principle of electromagnetic induction. When an AC current is passed through the excitation winding, an alternating magnetic field is generated at the pole shoes of the stator stack 1. The 120-degree sector-shaped magnetic conductive surface on the rotor stack couples with the pole shoes of the stator stack, inducing a voltage signal in the output windings A and B. Because the output windings A and B are connected differentially, the output voltage signal reflects the rotation angle of the rotor stack. The salient pole structure of the rotor stack further improves measurement accuracy and stability, ensuring that the output characteristic curve remains linear within a ±53° range.

[0057] The application scenarios of the present invention are mainly concentrated in areas that require large-angle measurement, such as aircraft landing gear, doors and other working environments with large actuation angles. The traditional four-pole RVDT is unable to meet the needs of the above scenarios because its range is limited to ±38°. The present invention successfully expands the effective measurement range to ±53° through an innovative three-pole design structure, solving the problem of insufficient range of traditional RVDT. During the design process, the present invention fully considers material selection and process optimization, and adopts iron-nickel soft magnetic alloy 1J79 or 1J50 as the material for stator laminations and rotor laminations to ensure that the laminations have excellent magnetic properties in practical applications. By strictly controlling the thickness of the laminations within the range of 0.2mm to 1mm, preferably 0.2mm, 0.3mm and 0.5mm thicknesses. To further improve the mechanical strength and magnetic properties of the laminations, the introduction of the heat treatment process not only optimizes the magnetic properties of the laminations, but also ensures the stability of the laminations in long-term use.

[0058] In summary, the innovation of the present invention lies in the first proposal of a three-pole RVDT structure, which breaks the idea of ​​traditional even-pole design and significantly expands the measurement range. By reducing the number of stator poles, the measurement range is expanded while ensuring the uniformity of the excitation magnetic field. The coupling effect of the salient pole structure on the rotor lamination and the stator lamination enables accurate detection of the rotor rotation angle. The layout of the electrical winding has been carefully designed, and the reasonable layout of the excitation winding, output winding A coil and output winding B coil ensures high linearity and stability of the output voltage signal. The present invention fills the technical gap of traditional RVDT in the range of ±38° to ±53°, and expands the application field of the product.

[0059] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0060] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A large-range three-pole rotary differential transformer, characterized in that: It includes a stator lamination and a rotor lamination; wherein the stator lamination is formed by pressing stator laminations to form a three-pole structure, and the pole shoe of each tooth covers an angle of 106°; the rotor lamination is formed by pressing rotor laminations, and the rotor lamination has a 120° fan-shaped magnetic conductive surface.

2. The differential transformer according to claim 1, wherein: The stator laminations and the rotor laminations are made of soft magnetic alloy material.

3. The differential transformer according to claim 2, wherein: The thickness of the stator laminations and the rotor laminations is 0.2 mm to 1 mm.

4. The differential transformer according to claim 1, wherein: The stator laminations and the rotor laminations have a saturation magnetic induction intensity greater than or equal to 0.75 T, a coercive force less than or equal to 1.6 A / m, and a maximum magnetic permeability greater than or equal to 225 mH / m.

5. The differential transformer according to claim 1, wherein: The thickness of the stator lamination is 5.5 mm, and the thickness of the rotor lamination is 7.5 mm.

6. The differential transformer according to claim 1, wherein: Also included are electrical windings, including an excitation winding, an output winding A coil, and an output winding B coil.

7. The differential transformer according to claim 1, wherein: The inner hole of the stator lamination is evenly provided with three slots, the angle covered by the pole shoe of each tooth is 106°, and the coupling angle between the 120° sector-shaped magnetic conductive surface and the pole shoe of the stator lamination is 53°.

8. The differential transformer according to claim 1, wherein: The rotor lamination has a salient pole structure, and the salient pole structure realizes detection of the rotor rotation angle through coupling with the stator lamination.

9. The differential transformer according to claim 6, wherein: The output voltage of the output winding A coil and the output winding B coil is proportional to the rotation angle of the rotor.

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