Bearing operating parameters:Power 30W; speed 3500r/min.
Bearing selection
Quiet operation is the main requirement for household appliance motors. The noise of an electric motor is affected by the quality of the bearings (shape and operating accuracy), bearing clearance, and the machining accuracy of the shaft and end cap holes.
At present, the quality of standard bearings is sufficient to meet general noise requirements. By using spring washers to apply a light preload along the axial direction to the bearing, zero clearance operation of the bearing can be achieved.
The mating parts of the bearings on the shaft and in the end cap holes must be aligned. In order to allow the spring washer to adjust the bearing axially, the outer ring must slide and fit in the end cap.
Install a set of deep groove ball bearings S605.2RS on one end of the motor and a set of 696.2Z.L91 on the other end.
Bearing suffix symbol
2Z - bearings with double-sided dust covers, which form a gap type seal.
L91- Fill with specialized lubricating grease (Arcanol L91).
Size selection of bearings
The shaft diameter is usually determined by mechanical structure design, and as a result, the determined bearing size can meet the fatigue life requirements with little occurrence of fatigue damage. The bearing has a required lifespan of 500 to 2000 hours.
Machining tolerance
The axis is j5; the end cap hole is H5. The tolerance H5 of the end cap hole can provide the required sliding fit for the free axial adjustment allowed by the two sets of bearings.
Taking 696ZZ bearing as an example
Bearing inner hole size: φ 6 0/-0.008mm
Bearing outer diameter size: φ 15 0/-0.009mm
Spindle size: φ 6 0.004/-0.002
Axis is j5, end cap hole size: φ 15+0.009/0, end cap is H5
Bearing inner hole and spindle fit: transitional fit
Maximum clearance: 0.002mm
Maximum interference fit: 0.012mm
Average interference fit: 0.005mm
Bearing outer diameter and end cap hole fit: clearance fit
Minimum clearance: 0mm
Maximum clearance: 0.018mm
Average gap amount: 0.009mm
Bearing lubrication and sealing
Lubricate with a particularly high cleanliness grade 2 lithium based grease, which has the characteristic of low friction. The overall efficiency of this type of electric motor is significantly affected by the friction torque of the ball bearings. Bearings with dust-proof differential (2ZR type) are pre lubricated with grease, which means no additional grease is required. The gap type seal composed of a dust cover can prevent pollution under general environmental conditions.
