Ceramic wire support for concentrated winding electric machines and method for manufacturing the same

Abstract

The application discloses a ceramic wire support for a concentrated winding motor and a preparation method thereof, and belongs to the technical field of ceramic materials and preparation thereof. The application solves the problems of poor size stability, insufficient precision of size control and the like of the existing wire support. The application takes silicon powder as a main body material, realizes rapid forming through compounding of a glue agent (urea-formaldehyde resin) and an inorganic (dihydrogen aluminum phosphate) adhesive agent, and then is subjected to high-temperature treatment, so that the ceramic wire support suitable for the concentrated winding motor under high-temperature application is obtained.

Description

Technical Field

[0001] This invention relates to a ceramic conductor support for a centralized winding motor and its preparation method, belonging to the field of ceramic materials and their preparation technology. Background Technology

[0002] Centrally wound motors typically require winding on conductor supports that can accommodate magnetic cores. These supports serve multiple functions, including supporting the coils, fixing the silicon steel sheets, and providing electrical insulation. Currently, conductor supports are mostly made of polymer materials such as LCP resin and unsaturated polyester resin, manufactured through processes such as injection molding, compression molding, or 3D printing. While these polymer-based materials can meet basic mechanical strength and insulation requirements at room temperature, their insufficient heat resistance is particularly prominent in high-temperature environments, especially in special applications such as aerospace micro-motors. High temperatures can cause the polymer materials to soften or even melt, leading to coil support failure, insulation damage, and in severe cases, motor burnout and other safety accidents.

[0003] To improve high-temperature resistance, attempts have been made to use ceramic materials to fabricate conductor supports. However, conventional ceramic products typically employ high-temperature sintering processes, which are lengthy, complex, and prone to shrinkage and deformation during sintering, making it difficult to meet the dimensional accuracy requirements of high-precision micromotors for installation and use. These issues limit the widespread application of ceramic conductor supports in the field of high-temperature special motors. Therefore, it is still necessary to explore a ceramic support fabrication method that combines good dimensional stability with simple and efficient processing to meet the demands of high-temperature and precision operating conditions. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a ceramic conductor support that is resistant to high temperature and can be rapidly formed. The ceramic conductor support has a low sintering temperature, fast forming speed, good heat resistance, and high mechanical strength.

[0005] The technical solution of this invention: One objective of this invention is to provide a method for preparing a ceramic conductor support, the method comprising the following steps: (1) Mix the silica powder, urea-formaldehyde resin powder, aluminum dihydrogen phosphate powder and sintering aid at room temperature to obtain a mixed powder; (2) After the mixed powder obtained in step (1) is pre-pressed, it is placed for 2 hours to set under conditions of 70-80% humidity and 40-45℃. (3) The product after the shaping process in step (2) is sintered to obtain a ceramic wire support.

[0006] Further specifying, the particle size of the silicon micropowder is 10~40μm.

[0007] Furthermore, the silica powder is composed of particles with diameters of 10μm, 20μm and 40μm mixed in a mass ratio of 1:(0.35-0.4):(0.18-0.2).

[0008] Further specifying, the sintering aids include copper oxide and magnesium oxide.

[0009] Furthermore, the mass ratio of copper oxide to magnesium oxide is 1:0.5.

[0010] Further specifying, the mass ratio of silica powder, urea-formaldehyde resin powder, aluminum dihydrogen phosphate powder and sintering aid is 1:(0.1-0.12):(0.15-1.8):(0.05-0.08).

[0011] Further specifying the sintering process, it is as follows: hold at 300℃ for 2 hours; then raise the temperature to 500℃ and hold for 1 hour; finally raise the temperature to 800℃ and hold for 3 hours.

[0012] The second objective of this invention is to provide a ceramic conductor support obtained by the above-mentioned preparation method.

[0013] The third objective of this invention is to provide an application of the above-mentioned ceramic conductor support, specifically for the preparation of a concentrated winding motor.

[0014] Beneficial effects: This invention uses silicon micropowder as the main material, achieves rapid molding by doping with an organic and inorganic composite adhesive, and obtains a ceramic support through high-temperature treatment. Compared with the prior art, it has at least the following advantages: (1) Excellent heat resistance and structural stability: This invention uses silicon micropowder as the main material, which fundamentally solves the problem of support failure caused by thermal softening of traditional polymer supports at high temperatures. By utilizing the extremely high thermal stability of silicon micropowder itself, the ceramic support can be reliably operated for a long time under extreme high-temperature conditions such as aerospace, effectively avoiding the risk of motor burnout.

[0015] (2) Low-temperature rapid sintering and energy saving and cost reduction: This invention differs from the shortcomings of traditional ceramics which require extremely high sintering temperatures. It cleverly utilizes the low surface softening temperature of silicon micropowder and, in conjunction with the introduction of nano-low melting point sintering aids, significantly reduces the sintering temperature of the material. This characteristic not only enables rapid densification sintering of silicon micropowder but also greatly reduces energy consumption and production cycle, meeting the needs of high-efficiency manufacturing.

[0016] (3) Rapid curing at room temperature and simplified process: The present invention uses an adhesive system composed of organic (urea-formaldehyde resin) and inorganic (aluminum dihydrogen phosphate) to achieve rapid curing at room temperature without high-temperature pretreatment. The rapid cross-linking reaction of urea-formaldehyde resin under acidic conditions allows the green body to obtain sufficient strength for demolding and handling in a short time, which greatly improves production efficiency and simplifies process equipment requirements.

[0017] (4) Strong environmental adaptability and high dimensional accuracy: The inorganic adhesive aluminum dihydrogen phosphate used in this invention not only provides hydrogen ion catalysis for the curing of organic resin, but also transforms into a ceramic phase after high-temperature treatment, enhancing the strength of the green body. At the same time, this composite system effectively suppresses the problem of a sharp increase in porosity caused by the volatilization of a single organic adhesive. Combined with a rapid sintering process, it significantly reduces sintering shrinkage and deformation, ensuring the dimensional accuracy and geometric tolerances of the support, and meeting the requirements of micro-motors for precision components. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0020] Example 1 The method for preparing the ceramic conductor support in this embodiment includes the following steps: (1) Powder compounding. Silica powder (10μm, 20μm and 40μm particle sizes mixed in a mass ratio of 1:0.35:0.18), urea-formaldehyde resin powder (model YHD-88, purchased from Jinan Yihengda New Material Technology Co., Ltd.), aluminum dihydrogen phosphate powder, and sintering aid were uniformly mixed at room temperature in a mass ratio of 1:0.1:0.15:0.08 to obtain a mixed powder. The sintering aid was obtained by compounding copper oxide and magnesium oxide in a mass ratio of 1:0.5.

[0021] (2) Support preforming. The mixed powder is pre-pressed (pre-pressing conditions are: room temperature pressing, 8MPa), and then placed at 80% humidity and 45℃ for 2 hours to set and cure.

[0022] (3) Sintering of the support. The solidified support is sintered by holding at 300℃ for 2 hours, 500℃ for 1 hour, and 800℃ for 3 hours to obtain a ceramic wire support.

[0023] Example 2 The difference between this embodiment and Embodiment 1 is that the silicon micropowder is a mixture of 10μm, 20μm and 40μm particles in a mass ratio of 1:0.4:0.2; the mass ratio of silicon micropowder, urea-formaldehyde resin powder, aluminum dihydrogen phosphate powder and sintering aid is 1:0.12:0.18:0.05; the remaining process steps and parameter settings are the same as in Embodiment 1.

[0024] Example of effect The properties of the ceramic wire supports prepared in Examples 1 and 2, as well as the unsintered shaped products, were characterized, and the test results are shown in Table 1 below.

[0025] Table 1 The surface resistivity was tested at a temperature of 23°C and a humidity of 50%.

[0026] As shown in Table 1 above, pre-pressed products utilize urea-formaldehyde resin in an acidic, aqueous environment. After degradation, formaldehyde is released, and the formaldehyde continues to react with the urea-formaldehyde resin molecular chains to form a cross-linked structure, achieving pre-curing and resulting in a cured support (an unsintered, shaped product). In this process, if the proportion of hydrogen ions is too low, molding will be too slow, leading to deformation under high humidity. Conversely, if the proportion of hydrogen ions is too high, molding will be too fast, causing rapid surface cross-linking, preventing moisture penetration, and hindering the formation of an internal cross-linked structure, resulting in cracking during sintering. Therefore, it is necessary to strictly control the ratio of urea-formaldehyde resin to aluminum dihydrogen phosphate to be 1:1.5.

[0027] Although urea-formaldehyde resin and aluminum dihydrogen phosphate form a bonding system, during sintering, due to the decomposition of the urea-formaldehyde resin, aluminum dihydrogen phosphate becomes the main binder of the silicon micropowder. When the amount of urea-formaldehyde resin is less than 10 wt% of the amount of silicon micropowder, the compressive strength of the unsintered device is less than 30 MPa, making it extremely prone to breakage during movement and handling. When the amount of urea-formaldehyde resin is higher than 12 wt%, more voids will remain after sintering, leading to a decrease in the compressive strength of the sintered device, and a significant reduction in insulation properties such as surface resistivity and breakdown field strength. Therefore, the ratio of silicon micropowder to urea-formaldehyde resin should be controlled at 1:(0.1-0.12).

[0028] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing a ceramic conductor support, characterized in that, include: (1) Mix the silica powder, urea-formaldehyde resin powder, aluminum dihydrogen phosphate powder and sintering aid at room temperature to obtain a mixed powder; (2) After the mixed powder obtained in step (1) is pre-pressed, it is placed for 2 hours to set under conditions of 70-80% humidity and 40-45℃. (3) The product after the shaping process in step (2) is sintered to obtain a ceramic wire support.

2. The preparation method according to claim 1, characterized in that, The particle size of the silica powder is 10~40μm.

3. The preparation method according to claim 2, characterized in that, Silica powder is made by mixing particles with diameters of 10μm, 20μm and 40μm in a mass ratio of 1:(0.35-0.4):(0.18-0.2).

4. The preparation method according to claim 1, characterized in that, Sintering aids include copper oxide and magnesium oxide.

5. The preparation method according to claim 4, characterized in that, The mass ratio of copper oxide to magnesium oxide is 1:0.

5.

6. The preparation method according to claim 1, characterized in that, The mass ratio of silica powder, urea-formaldehyde resin powder, aluminum dihydrogen phosphate powder and sintering aid is 1:(0.1-0.12):(0.15-1.8):(0.05-0.08).

7. The preparation method according to claim 1, characterized in that, The sintering process is as follows: hold at 300℃ for 2 hours; then raise the temperature to 500℃ and hold for 1 hour; finally raise the temperature to 800℃ and hold for 3 hours.

8. A ceramic conductor support obtained by the preparation method according to any one of claims 1 to 7.

9. An application of the ceramic conductor support as described in claim 8, characterized in that, Used in the preparation of concentrated winding motors.

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