Improved magnet assembly preparation method

Abstract

The invention discloses an improved magnet assembly preparation method, which comprises the following steps: preparing raw material mixed rubber magnetic powder of a magnet, upwards moving a concave die, a core rod and a shaft together by a specified same distance through a press, so that an annular cavity is formed among the concave die, a lower punch and the shaft, and filling the annular cavity with the mixed rubber magnetic powder; and the upper punch and the lower punch jointly press the mixed rubber magnetic powder in the annular cavity under the action of the press, so that a magnet is formed on the outer side of the shaft in the circumferential direction, and the shaft and the magnet are synchronously assembled. According to the preparation method of the improved magnet assembly, the mixed rubber magnetic powder is directly and integrally formed into the magnet on the circumferential outer side of the shaft through the mold and the press, the overall structural strength of the magnet assembly is improved, the dynamic balance characteristic of the magnet assembly is improved, the production process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of magnetic material molding and assembly technology, and in particular to an improved method for preparing magnet components. Background Technology

[0002] Currently, the assembly process between the magnet and the shaft involves pressing the mixed magnetic powder into shape using a mold and press (i.e., magnet forming), then curing, chamfering, and inspecting the magnet. The inspected magnet is then assembled with the shaft using adhesive, which fixes the magnet and shaft together with glue. This process has the following drawbacks: 1. The assembly of the magnet and the shaft requires positioning fixtures, which increases costs and procedures; 2. During assembly, glue is needed to fix the magnet and shaft. Uneven glue distribution will lead to unstable bonding strength. 3. During high-speed operation, the magnet and shaft are prone to separation due to unstable strength. 4. Adhesive bonding processes use adhesives, which result in VOC emissions, increase process costs, and impact carbon emissions and the environment.

[0003] The above problems seriously affect the reliability and service life of the product; therefore, this application proposes an improved method for manufacturing magnet components to solve the above problems. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide an improved method for manufacturing magnet components.

[0005] This invention provides an improved method for preparing a magnet assembly, which involves directly pressing mixed magnetic powder into a magnet using a mold and a press, and simultaneously assembling it onto a shaft. The method specifically includes the following steps: 1) Magnet assembly material preparation The resin and magnetic powder are mixed evenly in a certain proportion to obtain the mixed magnetic powder. 2) Magnet assembly molding In the initial state, the lower punch is installed through the interior of the die, the core rod is installed through the interior of the lower punch, and the shaft is placed inside the lower punch and located at the top of the core rod. The tops of the die, lower punch, and shaft are flush. The die, core rod, and shaft are moved upward together by a press by a specified distance, so that an annular cavity is formed between the die, lower punch, and shaft. The annular cavity is filled with the mixed magnetic powder. Under the action of the press, the upper punch and the lower punch together press the mixed magnetic powder inside the annular cavity, thereby forming a magnet on the circumferential outer side of the shaft, and the assembly between the shaft and the magnet is completed simultaneously. 3) Curing of magnet components The shaft and the magnet are subjected to high-temperature baking treatment to improve the mechanical strength of the magnet.

[0006] Furthermore, the magnetic powder in the mixed magnetic powder accounts for 95-99% by mass, and the resin accounts for 1-5% by mass.

[0007] Furthermore, the curing temperature of the high-temperature baking treatment is set to 120~200℃, and the curing time is set to 30~150 minutes.

[0008] Furthermore, the circumferential outer surface of the shaft at the point where it engages with the magnet is configured with a special structure to enhance the mechanical engagement force between the magnet and the shaft.

[0009] Furthermore, the special structures include, but are not limited to, shoulder structures, collar structures, knurled shafts, stepped shafts, and flange shafts.

[0010] Compared with the prior art, the beneficial effects of the present invention are: The improved magnet assembly preparation method of this invention places the assembly between the magnet and the shaft in the magnet forming stage. That is, the mixed magnetic powder is directly pressed into a magnet on the circumferential outer side of the shaft using a mold and a press. The magnet and the shaft directly form an integral structure during the magnet forming process, saving certain processes and costs, improving the structural strength of the assembly between the magnet and the shaft, and avoiding the problem of unstable bonding strength between the magnet and the shaft caused by traditional glue bonding methods. In addition, the position on the shaft where it meets the magnet is set with a special uneven structure, which increases the mechanical interlocking force between the magnet and the shaft, improving the reliability and service life of the product.

[0011] Meanwhile, the magnet components processed by the improved magnet component manufacturing method have advantages such as stable concentricity, stable dynamic balance, and no VOC emissions.

[0012] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0013] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the molding process of the magnet assembly. Figure 2 This is a schematic diagram of the structure after the magnet and shaft are assembled. Labels in the diagram: 1. Shaft; 2. Magnet; 3. Knurled structure; 4. Die; 5. Lower punch; 6. Core rod; 7. Annular cavity; 8. Mixed magnetic powder; 9. Upper punch. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0016] The magnet is formed by molding the mixed magnetic powder 8 using a mold and a press. First, the mold is installed on the press, and then the mixed magnetic powder 8 is shaped using the mold. The inner and outer diameters of the mold and the formula of the mixed magnetic powder 8 determine the size of the final product. The press provides the molding pressure.

[0017] Please refer to Figures 1-2 The present invention provides an improved method for preparing a magnet assembly, wherein the mixed magnetic powder 8 is directly pressed into a magnet using a mold and a press and then simultaneously assembled onto a shaft 1, specifically including the following steps: 1) Magnet assembly material preparation The resin and magnetic powder are mixed evenly in a certain proportion to obtain mixed magnetic powder 8; In the mixed magnetic powder 8, the magnetic powder accounts for 95-99% by mass, and the resin accounts for 1-5% by mass. 2) Magnet assembly molding Under the combined action of the mold and the press, the mixed magnetic powder 8 is integrally assembled onto the shaft 1. The mold is installed on the press and includes a die 4, a lower punch 5, a core rod 6, and an upper punch 9. The die 4 is arranged in a disc-shaped cylindrical shape. The lower punch 5 is arranged vertically through the middle of the die 4. The core rod 6 is arranged vertically through the middle of the lower punch 5. The shaft 1 of the magnet 2 to be assembled is placed inside the lower punch 5 and located at the top of the core rod 6. The assembled die 4, lower punch 5, core rod 6, and shaft 1 are coaxial. first step: In the initial state, the tops of the die 4, the lower punch 5, and the shaft 1 are flush. Step Two: The die 4, core rod 6 and shaft 1 are moved upward by the same distance by the press, so that the top of the lower punch 5 is located inside the die 4, thereby forming an annular cavity 7 between the die 4, the lower punch 5 and shaft 1. Step 3: The annular cavity 7 is filled with mixed magnetic powder 8; Step 4: Under the action of the press, the upper punch 9 moves downward toward the lower punch 5. That is, under the action of the press, the upper punch 9 and the lower punch 5 together press the mixed magnetic powder 8 inside the annular cavity 7. That is, a certain distance of the lower part of the shaft 1 extends into the interior of the lower punch 5 and is supported by the core rod 6. A certain distance of the upper part of the shaft 1 extends into the groove on the bottom end face of the upper punch 9. The mixed magnetic powder 8 forms a magnet 2 in the space between the lower punch 5 and the upper punch 9 and located on the circumferential outer side of the shaft 1. The assembly between the shaft 1 and the magnet 2 is completed simultaneously. The circumferential outer surface of the shaft where it engages with the magnet is designed with a special uneven structure to enhance the mechanical engagement force between the magnet and the shaft. The special structure includes, but is not limited to, a shoulder structure, a collar structure, a knurled shaft, a stepped shaft, and a flange shaft.

[0018] Step 5: Shaft 1 and magnet 2 are a single, integrated magnet assembly; 3) Curing of magnet components The shaft 1 and magnet 2 are subjected to high-temperature baking treatment to improve the mechanical strength of magnet 2; After the magnet assembly, in which shaft 1 and magnet 2 are integrally formed, is molded, the mechanical strength of the molded magnet 8 is very poor because the mixed magnetic powder 8 is made of resin and magnetic powder. In order to make the magnet assembly have sufficient mechanical strength, the magnet assembly needs to be baked at high temperature. The baking temperature and time are mainly determined by the resin. The curing temperature of the high-temperature baking treatment is 120~200℃, and the curing time is 30~150 minutes. The mechanical strength of the cured magnet can meet the requirements of the product. 4) Chamfering of magnet assembly Chamfer magnet 2 to remove burrs, flash, and foreign matter from its surface; After magnet 2 is cured, it meets certain mechanical strength requirements. It is necessary to treat the flash, burrs, and surface powder generated during magnet 2 pressing. Currently, the chamfering process is mainly handled by grinding and polishing machines. Corundum abrasive is placed inside the machine; the shape and size of the abrasive vary depending on the product to improve the chamfering effect. After the abrasive is placed in, the machine's operating frequency, time, and amplitude are adjusted as needed. The operating frequency is set to 20~40Hz, the operating time to 12~20 minutes, and the amplitude is adjusted according to the chamfering dimensions. Then, the product to be chamfered is placed in the machine. After chamfering, the product surface is free of burrs, flash, and foreign matter. 5) Magnet assembly inspection The outer diameter, height, distance from the end face of the shaft, and runout of magnet 2 and shaft 1 are inspected respectively. After the chamfer of magnet 2 is completed, the surface of magnet 2 is cleaned. According to the size requirements of the product, the product is tested. Different precision testing equipment is used according to the size accuracy requirements. After testing, it is confirmed whether this batch of products is qualified. Qualified products can be packaged and put into storage. Among them, the outer diameter of magnet 2 is measured with a micrometer with a test accuracy of 0.001mm, the distance between the top end face of magnet 2 and the top end face of shaft 1 is measured with a height micrometer with a test accuracy of 0.001mm, and the runout of magnet 2 and shaft 1 is measured with a roundness meter or CMM with an accuracy of 0.001mm.

[0019] Through the above process, the mixed magnetic powder 8 is directly molded into a magnet 2 on the outer circumference of the shaft 1 by the mold and press, which improves the overall structural strength, simplifies the production process, reduces the production cost, and avoids the problem of unstable bonding between the magnet and the shaft caused by the traditional adhesive bonding process. The test data for the traditional adhesive bonding process and the process described in this application are as follows: Table 1 Comparison of concentricity and imbalance of components processed by the two techniques.

[0020] As shown in Table 1, the concentricity and imbalance of the components assembled using the present application's assembly process are superior to those assembled using the adhesive bonding process.

[0021] Table 2 Comparison of axial pull-out force tests for components processed by the two techniques.

[0022] As shown in Table 2, the axial pull-out force of the assembly process in this application is better than that of the adhesive assembly process.

[0023] Table 3 Comparison of high-speed rotational speed tests of components processed by the two techniques.

[0024] Magnet dimensions: OD16 * ID5 * H9.8mm High-speed rotation test: This refers to rotating the component to be tested at an unconventional speed (usually close to or exceeding the required limit speed) while maintaining a constant temperature setting for the component according to the required temperature (to maintain the required temperature environment throughout the test), which is a systematic verification of the stability and reliability of the tested product. Before high-speed testing, the components need to be tested and adjusted using dynamic balancing equipment to ensure that the imbalance meets the test requirements before high-speed testing can be performed.

[0025] The ambient temperature of the fixed machine in the above test was 80℃. Under this condition, the magnet can resist the limit speed of breakage at high speed.

[0026] Table 3 shows that the components assembled using the present application's process can withstand higher rotational speeds in high-speed tests.

[0027] Table 4 Comparison of Axial Position Accuracy Tests for Component Magnets Processed by Two Different Techniques

[0028] Table 4 shows that the positional accuracy on the component magnets obtained by the two processes is basically the same.

[0029] In the description of this specification, the terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] In the description of this specification, the terms "one embodiment," "some embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An improved method for fabricating a magnet assembly, characterized in that, The mixed magnetic powder is directly pressed into magnets using a mold and press, and then simultaneously assembled onto a shaft. The specific steps include the following: 1) Magnet assembly material preparation The resin and magnetic powder are mixed evenly in a certain proportion to obtain the mixed magnetic powder. 2) Magnet assembly molding In the initial state, the lower punch is installed through the interior of the die, the core rod is installed through the interior of the lower punch, and the shaft is placed inside the lower punch and located at the top of the core rod. The tops of the die, lower punch, and shaft are flush. The die, core rod, and shaft are moved upward together by a press by a specified distance, so that an annular cavity is formed between the die, lower punch, and shaft. The annular cavity is filled with the mixed magnetic powder. Under the action of the press, the upper punch and the lower punch together press the mixed magnetic powder inside the annular cavity, thereby forming a magnet on the circumferential outer side of the shaft, and the assembly between the shaft and the magnet is completed simultaneously. 3) Curing of magnet components The shaft and the magnet are subjected to high-temperature baking treatment to improve the mechanical strength of the magnet.

2. The improved magnet assembly fabrication method according to claim 1, characterized in that, The magnetic powder in the mixed magnetic powder has a mass percentage of 95-99%, and the resin has a mass percentage of 1-5%.

3. The improved magnet assembly fabrication method according to claim 1, characterized in that, The curing temperature for the high-temperature baking treatment is set to 120~200℃, and the curing time is set to 30~150 minutes.

4. The improved magnet assembly fabrication method according to claim 1, characterized in that, The outer circumferential surface of the shaft at the point where it engages with the magnet is designed with a special uneven structure to enhance the mechanical engagement force between the magnet and the shaft.

5. The improved magnet assembly preparation method according to claim 4, characterized in that, The special structures include, but are not limited to, shoulder structures, collar structures, knurled shafts, stepped shafts, and flange shafts.

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