## 1 Introduction  
High-speed permanent magnet motors have a promising future. It is small, has a high power density, and can be directly connected to high-speed loads [1, 2]. The rotor structure is shown in Figure 1, and the mechanical strength of the magnets is poor, so additional sleeve protection is required. Two kinds of sleeves are commonly used, namely metal sleeves and composite sleeves. Among them, carbon fiber composite protective sleeves have the following advantages: they have weak conductivity, which reduces eddy current losses in the sleeve [3]; they also have low density, which increases motor power density; additionally, they have higher strength and require less thickness than other materials, maximizing the actual air gap of the motor and creating possibilities for electromagnetic coil design [4]. There are many scholars who have studied the composite sleeving of high-speed permanent magnet motors. For example, articles [5; 6; 7; 8] analyzed the stress and deformation of the sleeve under different operating conditions by analytical calculations and finite element methods. They calculated the preload or interference required for safe rotor operation of the sleeve. This ensures that both the structural strength of the rotor and the electromagnetic performance of the sleeve meet usage requirements. Although they designed the sleeve better, they ignored the effect of the sleeve preparation process on its performance. In fact, winding tension, winding angle, curing method, and choice of carbon fiber and resin in the preparation process all impact the performance of carbon fiber composite sleeves. Selecting a suitable sleeve preparation process to reduce sleeve thickness and improve sleeve performance is a key issue that needs urgent study. Therefore, this paper analyzes the carbon fiber composite sleeve preparation process parameters for high-speed permanent magnet motors one by one and summarizes suitable process parameters for practical use. Reference [9] analyzed different sleeve materials and thicknesses for the rotor of a 350 kW, 20,000 rpm motor and found that a thinner carbon fiber sleeve can reduce the electromagnetic loss of the motor. Reference [10] analyzed the multi-layer and multi-angle winding of carbon fiber sleeves for an 80 kW, 60,000 rpm motor. Reference [11] established a deformation and stress model for a multi-angle winding hybrid composite cylinder under axial load and internal and external pressure. Reference [12] studied the effect of composite winding angle and layer number on the bursting strength of pressure vessels using finite element models. Reference [13] studied the effect of composite fibers, matrix volume fraction, and winding angle variation on the compressive performance and axial bearing capacity of flat tubes. These studies focused on multi-layer and multi-angle winding analysis, finite element models, etc., but lacked experimental verification. Therefore, further experiments are needed to verify these theoretical results. The references for the winding process and testing are included in Table 1.  
References [14; 15] studied the effect of winding angle on the failure mode of carbon fiber composite materials. It was found that the compressive strength of composite materials