Bearing Installation Methods

Whether the bearing is installed or not will affect the accuracy, life and performance of the bearing. Therefore, please fully study the bearing installation, that is, please install the bearing according to the operating standards including the following items.

1. Clean the bearings and related parts; for grease-lubricated bearings and both sides with oil seal or dust cover, the seal ring bearing does not need to be cleaned before installation.

2. Check the size and finishing of the relevant parts

3. Installation method; the installation of the bearing should be determined according to the bearing structure, sizes, and the matching nature of the bearing parts.

The pressure is transmitted through the rolling elements, and the bearing installation generally adopts the following methods: a. Press-fit: When the inner ring of the bearing is tightly fitted with the shaft, and the outer ring and the bearing seat hole are loosely fitted, the bearing can be press-fitted on the shaft first, and then the shaft together with the bearing is installed into the bearing seat hole. When press-fitting, put a soft metal material on the end face of the inner ring of the bearing, and turn the hand of the assembly with a small amount of alcohol. The inner diameter should be slightly larger than the journal diameter, and the outer diameter should be slightly smaller than the bearing inner ring rib to avoid pressing on the cage.

The outer ring of the bearing is tightly fitted with the bearing seat hole, and when the inner ring and the shaft are loosely fitted, the bearing can be pressed into the bearing seat hole first. At this time, the outer diameter of the assembly sleeve should be slightly smaller than the diameter of the seat hole. If the bearing ring is tightly fitted with the shaft and the seat hole, the inner ring and the outer ring should be pressed into the shaft and the seat hole at the same time. b. Heating fit: An installation method in which a tight fit is transformed into a loose fit by heating the bearing or housing by thermal expansion. It is a common and labor-saving installation method. This method is suitable for the installation of bearings with a large amount of interference. The installation method of the bearing before shrinking depends on the bearing structure, fit and conditions. Generally, because most of the shaft rotates, the inner ring needs an interference fit. Cylindrical bore bearings are usually pressed in by a press, or by a shrink-fit method. In the case of a tapered hole, install it directly on the tapered shaft, or install it with a sleeve.

How to install the bearing correctly

Bearing should be installed in a dry, dust-free area as far as possible, and away from equipment that generates metal chips and dust. Contamination should be minimized when it must be installed in a complex environment.

  When installing bearings, mechanical, thermal, or hydraulic methods should be selected depending on the type and size.

1. Cylindrical bearing installation (Cold installation)

When installing a small bearing that is not too tight, you can use a sleeve and hammer the sleeve to lightly tap the sleeve to install the bearing in a proper position. When knocking, it should act on the bearing ring as evenly as possible to prevent the bearing from tilting or skewing.

Most bearings are installed by pressing in. If the inner and outer rings of the bearing are to be installed on the shaft and the bearing housing at the same time, it must be ensured that the same pressure acts on the inner and outer rings at the same time and must be on the same plane as the contact surface of the installation tool.

2. Hot mounting or installation

Typically, the installation of larger bearings is not possible without heating the bearing or housing, since as size increases, more force is required to install.

The temperature difference between the bearing ring and the shaft or housing required for hot mounting depends primarily on the interference and the diameter of the bearing fit.

The heating temperature of the open bearing shall not exceed 120. It is not recommended to heat bearings with seals and dust caps above 80°C (make sure that the temperature does not exceed the temperature allowed by the seals and grease). When heating the bearing, it should be heated evenly, and there must be no local overheating.

3. Taper bearing installation

For bearings with tapered holes, most of the inner rings are installed with an interference fit. The amount of interference is determined by the axial advance distance of the inner ring on the conical shaft diameter, adapter sleeve or withdrawal sleeve.

The greater the advance distance on the conical mating surface, the smaller the radial internal clearance of the bearing. The amount of interference can be determined by measuring the clearance reduction or the axial advance distance.

Small to medium bearings can be driven into position on the conical shaft diameter using a bearing installation tool or preferably a locknut. In the case of an adapter sleeve, use a socket nut that can be tightened with a hook or impact wrench. For the withdrawal sleeve, the bearing installation tool or end plate can be used to push it into the bearing inner bore.

The working principle of the oil injection method is that the hydraulic oil passes through the oil hole and the oil groove under high pressure, and is injected into the mating surface between the bearing and the shaft diameter to form an oil film. The oil film separates the mating surfaces so that friction between the mating surfaces is greatly reduced. This method is usually used when the bearing is mounted directly on a conical shaft diameter. The necessary oil holes and grooves should be part of the overall shaft design. This method can also be used to mount the bearing on the adapter or withdrawal sleeve if the adapter and withdrawal sleeves have been machined with oil holes and oil grooves.

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