An eddy current sensor and a preparation method thereof

Abstract

The present invention relates to an eddy current sensor and a preparation method thereof. The eddy current sensor may include a cylindrical main body and a central axis fixedly arranged in the cylindrical main body. A copper coating with a sinusoidal wave shape whose contour is mirror-symmetrical is cold-sprayed on the outer peripheral surface of the cylindrical main body, and a silver coating is cold-sprayed on the copper coating. The preparation method may include the following steps: providing a spraying tooling; fixedly installing the spraying tooling and the eddy current sensor to be sprayed together on the rotary chuck, so that only the area to be sprayed of the cylindrical main body is exposed; cold-spraying the copper coating; and cold-spraying the silver coating. By spraying a silver coating on the copper coating, the present invention can prevent the copper coating from being oxidized during use and extend the service life of the eddy current sensor.

Description

Technical Field

[0001] The present invention relates to the field of sensors, and particularly to an eddy current sensor for detecting the rotation of electric vehicle components and a preparation method thereof. Background Art

[0002] Existing eddy current sensors for detecting the rotation of electric vehicle components include a cylindrical main body and a copper conductive coating with a sinusoidal wave shape whose contour is mirror-symmetrical on the outer peripheral surface of the cylindrical main body. This conductive coating is usually a copper coating. Since copper is easily oxidized during use, it affects the performance and service life of the eddy current sensor. Summary of the Invention

[0003] The present invention aims to provide an eddy current sensor for detecting the rotation of electric vehicle components and a preparation method thereof to solve the above problems. For this purpose, the specific technical solutions adopted by the present invention are as follows:

[0004] According to one aspect of the present invention, an eddy current sensor is provided, which may include a cylindrical main body and a central shaft fixedly arranged in the cylindrical main body. A copper coating with a sinusoidal wave shape whose contour is mirror-symmetrical is cold-sprayed on the outer peripheral surface of the cylindrical main body, and a silver coating is cold-sprayed on the copper coating.

[0005] Further, the width of the widest part of the copper coating is 5 to 10 times the width of the narrowest part.

[0006] Further, the thickness of the copper coating is 0.1 to 0.2 millimeters.

[0007] Further, the number of sinusoidal wave periods of the copper coating is 5 to 10.

[0008] Further, the thickness of the silver coating is less than 50 micrometers.

[0009] According to another aspect of the present invention, a method for preparing the eddy current sensor as described above is provided. The method may include the following steps:

[0010] S100. Provide a spraying tooling, wherein the spraying tooling includes a first half, a second half, and a linkage shaft. Both the first half and the second half have a closed end and an open end. The linkage shaft is fixed to the closed end of the second half, including an inner end and an outer end located inside and outside the second half. The inner end is used to receive the central shaft, and the outer end is used to be clamped on a rotating chuck. The first half and the second half are used to fixedly clamp the eddy current sensor to be sprayed therein, so that a hollow corresponding to the shape of the copper coating is formed between the two open ends of the first half and the second half;

[0011] S102. Fix the spraying tooling and the eddy current sensor to be sprayed together on the rotary chuck, such that only the area to be sprayed of the cylindrical body is exposed.

[0012] S104. Cold spray a copper coating. Specifically, align the cold spray nozzle with the area to be sprayed, start the motor to drive the rotary chuck to rotate, and cold spray copper powder onto the area to be sprayed of the cylindrical body through the working gas.

[0013] S106. Cold spray a silver coating. Specifically, align the cold spray nozzle with the area to be sprayed, start the motor to drive the rotary chuck to rotate, and cold spray silver powder onto the copper coating through the working gas.

[0014] Further, both the first half and the second half are each composed of two semi-circular parts.

[0015] Further, the method further includes roughening the area to be sprayed before step S102.

[0016] Further, in S104, the working gas is nitrogen or helium heated to 500 - 900 °C, the copper powder feeding speed is 2 - 5 kg / h, the spraying pressure is 2 - 4 Mpa, and the spraying distance is 20 - 40 mm.

[0017] Further, in S106, the working gas is nitrogen or helium heated to 400 - 700 °C, the silver powder feeding speed is 2 - 5 kg / h, the spraying pressure is 2 - 4 Mpa, and the spraying distance is 20 - 40 mm.

[0018] The beneficial effects of adopting the above parameters are to improve the density and bonding strength of the copper coating and the silver coating, etc.

[0019] Adopting the above technical solution, the beneficial effect of the present invention is that by spraying a layer of silver coating on the copper coating, the copper coating can be prevented from being oxidized during use, and the service life of the eddy current sensor can be prolonged. Description of the Drawings

[0020] To further illustrate the embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principle of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0021] Figure 1 is a perspective view of an eddy current sensor for detecting the rotation of electric vehicle components according to an embodiment of the present invention;

[0022] Figure 2Yes Figure 1 Another perspective view of the eddy current sensor shown;

[0023] Figure 3 Yes Figure 1 A cross-sectional view of the conductive coating of the eddy current sensor shown;

[0024] Figure 4 Is for spraying Figure 1 A perspective view of the spraying tooling for the conductive coating of the eddy current sensor shown;

[0025] Figure 5 Yes Figure 4 An exploded view of the spraying tooling shown;

[0026] Figure 6 Yes Figure 1 The eddy current sensor shown and Figure 4 A perspective view of the spraying tooling shown installed together;

[0027] Figure 7 Shows a flowchart of a method for preparing the eddy current sensor shown Figure 1 ; Detailed implementation manners

[0028] The present invention will now be further described in conjunction with the accompanying drawings and specific implementation manners.

[0029] According to one aspect of the present invention, there is provided an eddy current sensor 1 for detecting the rotation of electric vehicle components. As shown Figures 1 to 3 it may include a cylindrical body 11 and a central shaft 12 fixedly provided within the cylindrical body 1. The central shaft 12 is used to connect to an external rotational drive device to drive the eddy current sensor 1 to rotate. A copper coating 13 with a sinusoidal wave shape that is mirror-symmetrical in profile is cold-sprayed on the outer peripheral surface of the cylindrical body 11, and a silver coating 14 is cold-sprayed on the copper coating 13. Since the conductivity of silver is similar to that of copper, but it is not easily oxidized; therefore, by covering a silver coating on the copper coating 13 as a protective coating, the copper coating 13 can be prevented from being oxidized during use, extending the service life of the eddy current sensor 1.

[0030] Preferably, the width W2 at the widest part of the copper coating 13 is 5 to 10 times the width W1 at the narrowest part. In a specific embodiment, the width W2 at the widest part of the copper coating 13 is 8.0 ± 0.1 mm, and the width W1 at the narrowest part is 1.0 ± 0.1 mm.

[0031] Preferably, the thickness of the copper coating 13 is 0.1 to 0.2 mm. In a specific embodiment, the thickness of the copper coating is 15.0 ± 0.1 mm.

[0032] The number of sine wave periods of the copper coating 13 can be designed according to the size of the cylindrical body 11. Generally, the number of sine wave periods of the copper coating 13 is 5 to 10.

[0033] To prevent the protective coating from affecting the performance of the eddy current sensor 1, the thickness of the silver coating 14 is generally set to be less than 50 microns, for example, 20 microns.

[0034] According to another aspect of the present invention, there is also provided a method for manufacturing the eddy current sensor 1 as described above. As Figure 7 shown, the method includes the following steps:

[0035] S100. Provide a cold spraying tooling 2, as Figures 4 - 6 shown. Specifically, the cold spraying tooling 2 may include a first half 21, a second half 22, a linkage shaft 23, etc. Among them, the shapes of the first half 21 and the second half 22 are similar, both in the shape of a box cover, that is, having a closed end and an open end. The linkage shaft 23 is fixed to the closed end of the second half 21, including an inner end 231 and an outer end 232 located inside and outside the second half 2. The inner end 231 is used to receive the central shaft 12 of the eddy current sensor 1, and the outer end 32 is used to be clamped on a rotating chuck (not shown). In use, the first half 21 and the second half 22 fix and clamp the eddy current sensor 1 (specifically, the cylindrical body 11) therein, so that a hollow corresponding to the shape of the copper coating 13 to be cold sprayed is formed between the two open ends of the first half 21 and the second half 22. That is to say, the first half 21 and the second half 22 surround (cover) the cylindrical body 11 of the eddy current sensor 1, leaving only the area to be cold sprayed (that is, the area corresponding to the copper coating 13) exposed.

[0036] For the convenience of processing and disassembly, both the first half 21 and the second half 22 are composed of two semi-circular parts 21a, 21b and 22a, 22b. That is to say, both the first half 21 and the second half 22 adopt a structure similar to a clamp. Specifically, the radial ends of the semi-circular parts 21a, 21b, 22a, 22b are provided with flanges 211a, 211b, 221a, 221b, and screw holes are provided on the flanges 211a, 211b, 221a, 221b. The two semi-circular parts 21a, 21b and 22a, 22b are fixedly connected together by four screws 26 in cooperation with the screw holes.

[0037] The closed end of the cylindrical body 11 of the eddy current sensor 1 has a number of first through holes 16 ( Figure 2As shown (there are 3 in total), second through-holes 212 and 221 corresponding to the first through-hole 16 are provided at the closed ends of the first half 21 and the second half 22. The eddy current sensor 1 and the first half 21 and the second half 22 can be fixed together by bolts 24 passing through the first through-hole 16 and the second through-holes 212 and 221 and tightened with nuts 5. The bolts 24 play a role in fixing and positioning to ensure that the eddy current sensor 1 will not shift during the spraying process.

[0038] The linkage shaft 23 includes a flange 233 in the middle and cylindrical parts 231 and 232 at both ends. Among them, the flange 233 is used to be fixed on the second half 22. The inner cylindrical part 231 has a cavity, and this cavity is used to receive the central shaft 12 of the eddy current sensor 1. The outer cylindrical part 232 is a solid cylinder. Since the inner cylindrical part 231 needs to receive the central shaft 12 and the outer cylindrical part 232 is a solid cylinder. Therefore, the diameter of the outer cylindrical part 232 can be set to be smaller than the diameter of the inner cylindrical part 231 to save material costs.

[0039] S102. Fix and install the spraying tooling 2 and the eddy current sensor to be sprayed together on the rotating chuck, so that only the area to be sprayed of the cylindrical body is exposed. Specifically, first fix and clamp the linkage shaft 23 on the rotating chuck, then fix the second half 22 and the linkage shaft 23 together, then position the eddy current sensor 1 and the first half 21 together through the bolt 24, and then pass the bolt 24 through the second through-hole of the second half 22 and tighten it with the nut 25 to complete the installation, as Figure 5 shown. It should be understood that fixing and clamping the linkage shaft 23 on the rotating chuck can also be completed at the end.

[0040] S104. Cold spray a copper coating. Specifically, aim the cold spray head at the area to be sprayed, start the motor to drive the rotating chuck to rotate, and cold spray the copper powder onto the area to be sprayed of the cylindrical body 11 through the working gas. The specific process parameters for cold spraying in this step are set as follows:

[0041] The particle size of the copper powder is 10 - 20 μm; the working gas uses high-purity helium, the purity of helium is 99.9%, the spraying distance is 10 - 20 mm; the spraying temperature (i.e., the heating temperature of the working gas) is 600 - 650 °C; the copper powder feeding speed is 7.0 - 7.5 kg / h; the spraying pressure is 2.5 - 2.7 Mpa; the working gas speed is 2.0 - 2.2 m 3 / min.

[0042] S106. Cold spray a silver coating. Specifically, aim the cold spray head at the area to be sprayed, start the motor to drive the rotating chuck to rotate, and cold spray the silver powder onto the copper coating through the working gas. The specific process parameters for cold spraying in this step are set as follows:

[0043] The particle size of the silver powder is 10 - 20 μm; the working gas is high-purity helium with a purity of 99.9%, the spraying distance is 10 - 20 mm; the spraying temperature (i.e., the heating temperature of the working gas) is 500 - 550 °C; the silver powder conveying speed is 6.0 - 6.5 kg / h; the spraying pressure is 2.1 - 2.2 Mpa; the working gas speed is 2.0 - 2.2 m 3 / min.

[0044] It should be understood that other inert gases can also be used as the working gas, such as nitrogen, argon or their mixtures. Process parameters such as the spraying pressure, spraying distance, spraying temperature, and powder conveying speed can also be adjusted according to the actual situation. Appropriate spraying pressure, spraying distance, spraying temperature, and powder conveying speed are beneficial to ensuring that the coating has good adhesion, thereby ensuring that the performance requirements of the sensor are met.

[0045] In addition, in order to improve the adhesion of the copper coating 13, before spraying (specifically, step S102), the surface of the area to be sprayed 15 (as Figure 2 shown) needs to be roughened so that its roughness reaches a preset value. Specifically, the surface of the area to be sprayed 15 is roughened by means such as sandblasting to increase the surface roughness so that the Ra value of the roughness reaches more than 3.2.

[0046] Although the present invention has been specifically shown and described in connection with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them are within the protection scope of the present invention.

Claims

1. A method for preparing an eddy current sensor, characterized in that, the eddy current sensor includes a cylindrical main body and a central axis fixedly arranged in the cylindrical main body, a copper coating with a sinusoidal wave shape that is mirror-symmetrical in contour is cold-sprayed on the outer peripheral surface of the cylindrical main body, and a silver coating is cold-sprayed on the copper coating; the method comprises the following steps: S100. Provide a spraying tooling, wherein the spraying tooling includes a first half, a second half and a linkage shaft. Both the first half and the second half have a closed end and an open end. The linkage shaft is fixed to the closed end of the second half and includes an inner end and an outer end located inside and outside the second half. The inner end is used to receive the central axis, and the outer end is used to be clamped on a rotating chuck. The first half and the second half are used to fixedly clamp the eddy current sensor to be sprayed therein, so that a hollow corresponding to the shape of the copper coating is formed between the two open ends of the first half and the second half; S102. Fix and install the spraying tooling and the eddy current sensor to be sprayed together on the rotating chuck, so that only the area to be sprayed of the cylindrical main body is exposed; S104. Cold-spray the copper coating. Specifically, align the cold spray head with the area to be sprayed, start the motor to drive the rotating chuck to rotate, and cold-spray the copper powder onto the area to be sprayed of the cylindrical main body through the working gas; S106. Cold-spray the silver coating. Specifically, align the cold spray head with the area to be sprayed, start the motor to drive the rotating chuck to rotate, and cold-spray the silver powder onto the copper coating through the working gas.

2. The method according to claim 1, characterized in that, both the first half and the second half are composed of two semi-circular parts.

3. The method according to claim 1, characterized in that, it further includes roughening the area to be sprayed before step S102.

4. The method according to claim 1, characterized in that, in S104, the working gas is nitrogen or helium heated to 500 - 900 °C, the copper powder feeding speed is 2 - 5 kg / h, the spraying pressure is 2 - 4 Mpa, and the spraying distance is 20 - 40 mm.

5. The method according to claim 1, characterized in that, in S106, the working gas is nitrogen or helium heated to 400 - 700 °C, the silver powder feeding speed is 2 - 5 kg / h, the spraying pressure is 2 - 4 Mpa, and the spraying distance is 20 - 40 mm.

6. An eddy current sensor prepared by using the method according to any one of claims 1 - 5, characterized in that, the width of the widest part of the copper coating is 5 - 10 times the width of the narrowest part.

7. The eddy current sensor according to claim 6, characterized in that, the thickness of the copper coating is 0.1 - 0.2 mm.

8. The eddy current sensor according to claim 6, characterized in that, the number of sinusoidal wave periods of the copper coating is 5 - 10.

9. The eddy current sensor according to claim 6, characterized in that, the thickness of the silver coating is below 50 microns.

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