Plastic bearings have good mechanical strength, wear resistance, self-lubricating properties, high and low temperature resistance, as well as acid, alkali, and corrosion resistance. They are also lightweight and low-noise, and can be used in environments that ordinary bearings cannot adapt to, such as anti magnetic electrical insulation, acid, alkali, seawater, chemical washing, and transmission.

Application fields of plastic bearings: 1. Medical equipment, low-temperature engineering, optical instruments, food processing machinery. 2. Working in special working conditions such as flammable, explosive, highly corrosive, vacuum, electrical insulation, non-magnetic, and dry friction is required in the petroleum, chemical, textile, machinery, and food industries.

Installation of plastic bearings

When installing bearings, it is necessary to apply equal pressure around the circumference of the end face of the ring. In order to install the ring, it is strictly prohibited to use hammers or other (metal) heavy objects to directly strike the end face of the bearing to avoid damaging the bearing. In addition, if pressure is applied to one side of the ring (such as the outer ring) and the other side of the ring (such as the inner ring) is pressed in by the rolling elements, it often causes indentation or abrasion on the rolling surface, which should not be used, especially when installing non separable bearings on both the shaft and the bearing housing. When installing bearings, the temperature range of the plastic material used in plastic bearings should be considered. If the temperature is too high, it will damage the bearing in the first place,

Coordination of Plastic Bearings

1. Excess fit

Fixing the inner and outer rings of the rolling element onto the shaft or bearing housing, when subjected to load, prevents relative movement in the radial, axial, and rotational directions between the ring and the shaft or bearing housing mating surface. This relative movement can cause friction, friction corrosion, or friction cracks on the mating surface, leading to damage to the bearing, shaft, and bearing housing. As a result, friction powder can mix into the interior of the bearing, causing poor operation, abnormal heating, or vibration.

The best way to fix bearings is to leave interference fit on the mating surface between the ring and the shaft or bearing housing for static fit. This fit can evenly distribute the load of the thin-walled ring on the circumference without affecting the bearing's load capacity. However, when using a static fit, besides the inconvenience of installing and disassembling the bearing, if a separated bearing is used, it cannot move axially, so it cannot be used in all situations.

2. The choice of cooperation

The selection of fit is generally based on the following principles: according to the direction and nature of the load acting on the bearing and which side of the inner and outer rings rotates, the load borne by each ring can be divided into rotational load, static load, or non directional load. The ring that bears rotational load and non directional load should adopt static fit (interference fit), and the ring that bears static load can adopt transitional fit or dynamic fit (clearance fit). When the bearing load is large or it is subjected to vibration or impact load, its interference fit must be increased. When using hollow shafts, thin-walled bearing boxes or light alloy or plastic bearing boxes, the interference fit must also be increased

When maintaining high rotational accuracy, high-precision bearings must be used and the dimensional accuracy of the shaft and bearing housing must be improved to avoid excessive interference. If the interference fit is large, the geometric shape accuracy of the bearing or axle box can affect the geometric shape accuracy of the bearing ring, thereby damaging the rotational accuracy of the bearing. If both the inner and outer rings of non separable bearings (such as deep groove ball bearings) use static fit, the installation and disassembly of the bearing will be extremely inconvenient. It is best to use dynamic fit on one side of the outer ring,

3. Recommended cooperation

Regarding the tolerances of the shaft diameter and bore size for installing bearings and bearing housings, ISO 283 (Dimensional Tolerances and Fit) has corresponding standards in the metric series. Therefore, the fit tolerance has been determined according to the selected shaft diameter and bore size tolerances.