Matters needing attention in motor end cover design

The design of the motor end cover structure mainly involves three factors: one is to have sufficient strength and rigidity; the other is to function, such as selecting the appropriate bearing type, size and lubrication system, the built-in collector ring should be equipped with a brush device for inspection There should be enough ventilation holes to protect the motor end cover; the third is the manufacturability, such as ensuring the manufacturability and feasibility of the end cover casting, processing, assembly and disassembly. Based on the above factors, the weight ratio of the end cover in the motor structure design is very high, and any changes will have a fatal impact on the overall level of the motor.

Motor end cover casting and its processing technology: In order to facilitate forming, modeling and machining, the geometry of the inner and outer parts of the end cover should be as simple as possible, and the contour should be as straight as possible. The length direction of the end cap must have a suitable slope so that the mold can be pulled out during casting. The wall thickness of gray iron castings should generally not be less than 5 mm to avoid cracks; however, thick sections should not be used to prevent shrinkage, loosening and cracks. The thickness difference of the workpiece should not be too large, so that the entire casting can be cooled evenly and prevent the internal stress from being too large and cracking.

Parts with insufficient strength and rigidity should adopt a shape or T-shaped section structure to avoid local thickness increase. When considering the stiffness of the motor end caps, it must be noted that the stress loads imposed on the end caps due to clamping and cutting during machining are much greater than the stress loads when the motor is running. In order not to cause deformation of the end cap during clamping and machining, the stiffness of the end cap is usually increased by adding ribs. This is especially important for end caps with large windows.

In order to facilitate processing, the bearing chamber is made into a through hole. However, the through-hole bearing chamber is easily deformed by direct clamping. Therefore, three or four joints are generally designed outside the motor end cover, which are specially used for jaw clamping. The outer end of the bearing chamber with stepped holes extends longer and is more rigid, and can be clamped to the outer end of the bearing chamber for machining.

There should be a distance of 5-10 mm between the lugs of the small motor end cover and the end face of the base. In this way, the cutting distance of the machined end face is shortened, and the combination of the motor end cover and the machine base is also more stable.