Machining Refers to the Process of Cutting the Redundant Parts of the Blank with a Cutting tool
Overview of machining process of motor products
Machining is an important part of the motor manufacturing process. The matching precision, dimensional accuracy and roughness of the motor components are mainly realized by mechanical processing means. The level of mechanical processing quality directly affects the quality of the motor and meets the design goals, which has a great impact on the performance and life of the motor. Among all machine tools and equipment used in batch production of small-scale asynchronous motor factories, mechanical processing equipment accounts for about 40-50%, and mechanical processing accounts for about 25-30% of the total labor required to manufacture motors.
At present, the percentage of machining labor in the motor manufacturing industry is gradually decreasing. This is due to the continuous improvement of parts structure and workmanship and the continuous improvement of the accuracy of blank manufacturing, which reduces the workload of mechanical processing. With the continuous improvement of the performance of metal cutting machine tools and cutting tools, as well as the use of modular machine tools, assembly lines or automatic production lines, the productivity of mechanical processing has been significantly improved. However, this does not mean that the role of machining process research in motor manufacturing tends to be marginalized, and the importance of process solutions and process routes is more prominent.
The parts that need to be machined in the motor are: Motor base, end cover, shaft, rotor bracket, rotor, stator, bearing cover, commutator, slip ring. And the bottom plate, bearing housing, bearing bush, etc. of large motors. How to choose the machining benchmark and processing plan to meet the technical requirements is the basic problem of machining. Here, the characteristics of several large-scale motor parts processing are discussed in detail, and the key elements and their control methods are clarified.
Interchangeability of motor components
In mass production and mass production of parts and components, without selection and repair, arbitrarily take out a part or component of the same specification, can be successfully assembled to the product, and can ensure the quality of the product. The nature of such parts or components of the same specification that can be interchanged is referred to as the interchangeability of the parts or components.
Parts are interchangeable and can be professionally produced by specialized workshops or factories, using advanced manufacturing methods to greatly increase labor productivity and reduce product costs. At the same time, assembly time can be shortened and the quality of the assembly can be improved. In terms of repair, when a part or part is damaged, it can be quickly replaced with a new part or part. The greater the scale of production, the more important the interchangeability of components. In terms of the unit of use, the motor itself is often used as a component or component. First, motors of the same specification are required to be interchangeably installed, and secondly, detachable parts are required to be used interchangeably.
Dimensions related to installation and maintenance
● Center height H, the height from the center of the shaft to the plane of the foot;
● shaft extension diameter D and length E, keyway width P and shaft groove depth G;
The transverse center distance A of the foot hole and its distance to the center line A/2
The axial center distance B of the bottom foot hole and the distance C from the shoulder to the first bottom foot hole;
● foot hole diameter K;
● stator inner diameter and rotor outer diameter;
● The matching size of the end cover and the base seat;
● The size of the bearing and bearing gear and bearing chamber,
● The size of the outer fan and the outer slip ring and the shaft extension.
Among them, A, B, C, D, H are the main installation sizes to ensure the interchangeability of the motor; Interchangeability is generally achieved by machining.
Mechanical processing characteristics of motor parts:
The machine tools and cutting tools used in the machining of motor parts are not much different from those of general machine manufacturers.
However, due to the influence of the structure and electromagnetic performance of the motor, the following characteristics must be paid attention to when machining the motor components:
● The air gap has a great influence on the performance of the motor. When formulating the machining plan of the motor components, the coaxiality of the components and the reliability of the mating surfaces should be fully paid to ensure the size and uniformity of the air gap.
● Compared with ordinary machine parts, the structural rigidity of the motor base and end cover is poor. It is easy to deform or vibrate during clamping and processing, which affects machining accuracy and roughness.
● For parts with integrated materials, such as stators, rotors, commutators and slip rings, etc., during machining. Can not use oil, soap liquid and other coolants, can not make metal chips fall into the insulation part, so as to avoid deterioration of insulation performance; It is better to prevent chips from getting stuck in the insulation material and causing insulation damage.
● For magnetically conductive parts, the cutting stress should not be too large to avoid lowering the magnetic permeability and increasing the iron loss.