Mounting and dismounting. Mounting. Mounting of Bearings. Bearings with Cylindrical Bore. Bearings with Tapered Bore

MOUNTING AND DISMOUNTING

Mounting

Ball and roller bearings should be mounted by qualified personnel paying special attention to keeping them clean: this is very important for ensuring satisfactory operation of bearings and preventing their premature breakdown. Preparation for Mounting

The mounting should be preferably done in a room with dry clean air locat ed far from the sources of dust, emulsion, dirt. The shaft and housing sur faces mating with the bearings should be thoroughly washed with gasoline or kerosene, wiped, dried and coated with a thin layer of lubricant. Care must be taken to check the accuracy of dimensions and shapes of all the parts mating with the bearing; the accuracy should comply with the requirements of GOST 332585. The shoulder sizes of the fasteners of all bearing types should con form to the requirements of GOST 2022682, and in the case of spherical roller bearings they should not exceed the dimensions d1 and D1.

The manufacturer's packing is to be removed from the bearings immedi ately before mounting to prevent penetration of dirt. Preservative coating is removed from the mounting surfaces only. The mounting surfaces are to be washed with gasoline or kerosene and wiped dry with clean napfree cloth. If a bearing is dirty or its packing is damaged, it should be thoroughly washed prior to mounting. The mounting surfaces in this case are to lubricated with mediumviscosity oil.

Prior to mounting, check the bearing appearance, marking, ease of rota tion, clearances for compliance with the requirements of the technical docu ments and this Catalogue.

Radial clearances in spherical roller bearings are measured with the aid of a set of feeler gauges, or by other methods. Feeler gauges are used to meas ure clearances between the outer ring and the unloaded roller. Prior to mounting, bearings, especially those with the ratio of the length and the largest shaft diameter exceeding 8, must be tested for straightness (absence of bending).

Mounting of Bearings

The method of bearings mounting (mechanical, hydraulic, thermal) depends on their type and size. In all the cases, it is very important to protect rings, bearing cages, rolling elements against direct knocks, because they can damage the bearings. The principal rule to be observed when mounting a bearing is never to allow the compressing force to be transferred through rolling elements.

When mounting a bearing, it is necessary to ensure the required precision

of the bearing rings location with respect to the rotation axis which mainly depends on the absence of misalignment. Misalignments of rings is one of the factors causing initial dam age of bearings and concentration of contact stresses. The operating misalignment of the rings should not exceed 0,7 maximum design permissible angle of alignement of the bearing rings under normal operating conditions (this parameter is to be taken from the description of bearing groups).

It should be borne in mind that the outer ring of a spherical radial bearing has the prop erty of readily swivel out. To replace the ring in its original position, it is necessary to set the dislocated (braking) rollers, with the aid of fingers, back into the outer ring and restore the latter to its original position. NEVER knock on the ring or rollers with a hammer.

Bearings with Cylindrical Bore

When mounting inseparable bearings, usually the ring with a tighter fit is to be mounted the first. If preloading in the tight fit is not too high, smallsize bearings can be mounted by knocking lightly with a hammer on the sleeve installed on the front end of the bearing ring.

Knocks should be uniformly distributed over the circumference to prevent the bear ing from misalignment. When an aligning bar is used instead of the sleeve, the force must be applied at the center (see Sketch 1). If the bearing is inseparable, it should be simulta neously pressurefitted onto the shaft and into the housing seat (see Sketch 2) with the aid of the mounting tool shown in the sketch, a mounting ring is inserted between the bear ing and the aligning bar, resting on the front

ends of the inner and outer rings. The supporting surfaces of the mounting ring should lie in the same plane to ensure even distribution of the forces applied to both rings during the mounting procedure. When mounting selfaligning bearings, for example, spherical roller