PM stepper motor injection-molded rotor and manufacturing method thereof

Abstract

The invention relates to a PM stepper motor injection-molded rotor and a manufacturing method thereof. The rotor comprises a shaft, a magnet rack, a magnetic material layer, and an injection molding structure. The magnet rack sleeves the shaft. The magnet rack and the magnetic material layer are injection-molded as one through the injection molding structure. The internal diameter of the magnet rack is connected with the shaft in an interference fit manner. The manufacturing method comprises the following steps: (1) using a mold to machine a magnet rack of a boss structure, wherein the magnet rack is provided with a center through hole, and the outer circumference of the base of the boss is provided with a slot; (2) pressing a shaft into the magnet rack in step (1), and making the shaft connected with the internal diameter of the magnet rack in an interference fit manner; and (3) injection-molding the magnet rack and a magnetic material layer as one. Compared with the prior art, the PM stepper motor injection-molded rotor has the advantages of high reliability, high production efficiency, low manufacture cost, and the like.

Description

technical field [0001] The invention relates to an injection molding rotor, in particular to a PM type stepping motor injection molding rotor and a manufacturing method thereof. Background technique [0002] There are generally two methods in the prior art for PM-type stepper motor injection molding rotors. The first method is to knurling on shaft 1 (such as figure 1 ) or machine a small groove on axis 1 (such as figure 2 ), and finally the shaft, the injection molding material 3, and the magnetic material 2 are injection molded together (such as image 3 ); the second way is to knurling on the aluminum sleeve 4 (or copper sleeve) (such as Figure 4 ), and then press the shaft into the aluminum sleeve 4 (or copper sleeve) (such as Figure 5 ), and finally integrated with magnetic material injection molding (such as Image 6 ). [0003] The defective that existing technology exists has: [0004] The first approach: [0005] 1. Due to the processing of knurls (or groov...

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Problems solved by technology

[0005] 1. Due to the processing of knurls (or grooves) on the shaft, the production efficiency of the shaft is low, the delivery time is long and the cost is high.

[0006] 2. Due to the space limitation of processing knurling (or groove), the bonding area with the injection molding material is small, resulting in insufficient bonding force between the shaft and the injection molding material

[0007] 3. In terms of technology, the hardness of the shaft and the knurling (or groove) requirements are relatively high. If the control is not good, it is easy to cause the shaft to break

[0009] 1. Since the aluminum sleeve (or copper sleeve) is a metal processing part, there will be problems of low production efficiency, long delivery time and high cost

[0010] 2. Press the aluminum sleeve (or copper sleeve) on the shaft, and finally inject it into an integrated one. This process is difficult to automate

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