The Correct Method of Bearing Disassembly

Daily maintenance or damage to the machine or equipment will need to remove the bearing, especially due to bearing failure and disassembly, check the parts around the bearing, lubricants and bearing itself, which helps to find the cause of the failure and need to improve the area, to solve the problem. So how to remove bearings correctly? What are the disassembly methods? How do you choose your tools? Today we will share with you a dry goods.

How to disassemble the bearing?

1.  it is best in experienced personnel or under their guidance.

2.  before the disassembly begins, determine the specific method to be disassembled. 

3.  have the necessary bearing removal tools at hand. 

4.  When re-using or checking disassembled bearings, pay attention to avoid scratching or damaging the bearing raceway or rolling element; When removing the bearing from the bearing seat, the disassembly force is applied to the outer ring; Remove the bearing from the shaft and apply the removal force to the inner ring.

The main method of disassembling bearings?

1.  the use of hand or hydraulic 

2.  only special wrench 

3.  the use of pulling tools 

4.  the use of induction heating equipment (inner ring) 

5.  the use of oil injection method

How do I select different tools?

Remove bearings mounted on cylindrical diameter

1.Cold disassembly

When removing smaller bearings, they can be removed from the shaft by gently tapping the side of the bearing ring with a suitable punch, preferably using a mechanical puller. The pull should be applied to the inner ring or adjacent parts. The removal process can be simplified if the shaft shoulder and the bearing seat hole shoulder are reserved for grooves to accommodate the puller's pull grip. In addition, a number of threaded holes are machined in the position of the hole shoulder to facilitate the bolt to push the bearing out.

The force required by large and medium-sized bearings is usually greater than that provided by mechanical tools. Therefore, it is recommended to use hydraulic power tools or oil injection method, or both. This means that oil holes and oil grooves need to be designed on the shaft.

2.Hot disassembly

When removing the inner rings of needle roller bearings or NU, NJ, and NUP cylindrical roller bearings, the thermal removal method is suitable. Two commonly used heating tools: heating ring and adjustable induction heater.

The heating ring is usually used to install and remove the inner ring of small and medium-sized bearings of the same size. The heating ring is made of light alloy. The heating ring is radially slotted and equipped with an electrically insulated handle.

If the inner rings of different diameters are often removed, it is recommended to use an adjustable induction heater. These heaters can quickly heat the inner ring without heating the shaft. When removing the inner rings of large cylindrical roller bearings, some special stationary induction heaters can be used.

3.Remove the bearings mounted on the cone diameter

Small bearings can be removed by using mechanical or hydraulic power puller to pull the inner ring. Some pullers are equipped with spring operating arms, using this puller with a self-matching core design can simplify the procedure and avoid damage to the journal. If the puller claw cannot be used on the inner ring, the bearing should be removed via the outer ring or by a puller combined with a puller.

When using the oil injection method, the disassembly of medium and large bearings will be safer and simpler. In this method, hydraulic oil is injected between two conical mating surfaces under high pressure through the oil hole and the oil tank. Friction between the two surfaces is greatly reduced, and axial forces are created that separate the bearing and shaft diameter.

4.Remove the bearing on the set sleeve

For the small bearings installed on the straight shaft of the tight sleeve, a hammer can be used to knock the small steel block uniformly acting on the end face of the bearing inner ring to disassemble. Before doing this, you need to loosen the lock nut of the set sleeve several turns.

The small bearings mounted on the step shaft of the set sleeve can be removed by hitting the small end face of the lock nut of the set sleeve with a special sleeve. Before doing this, you need to loosen the lock nut of the set sleeve several turns.

For bearings mounted on a tight-fitting sleeve step shaft, hydraulic nuts can be used for easier bearing disassembly. For this reason, a suitable stop device must be installed in the position close to the hydraulic nut piston. The oil injection method is a simpler method, but a tight sleeve with oil holes and oil grooves must be used.

5.Remove the bearing on the return sleeve

The locking device must be removed when removing the bearing on the return sleeve. (such as locking nuts, end plates, etc.) For small and medium-sized bearings, locking nuts, hook wrenches or impact wrenches can be used to disassemble.

For medium and large bearings mounted on the release sleeve, hydraulic nuts can be easily removed. It is recommended to install a stop device behind the hydraulic nut at the shaft end. The stop device can prevent the release sleeve and the hydraulic nut from flying out of the shaft when the release sleeve is suddenly separated from the matching position.

These points should be noted

1. Be sure to check whether there are cracks, sharp sources, fractures, fragments or deformation before disassembly;

2. when using the press, all parts are stable, do not shake or tremble; When pressing the shaft, the center of the shaft must be aligned with the center of the hammer; Do not grip the shaft when exerting force; Place a plate to catch the shaft or bearing so that it does not fall to the ground;

3.when using the puller, make sure that the puller claw is stuck on the side of the bearing; Align the end of the load bolt on the drawing tool with the shaft; If the jaw becomes loose during operation, stop immediately, and resume operation after changing position. If the bearing fails to come out after applying the normal disassembly force, do not apply excessive force to the puller and use other methods.

4.the use of professional wrench (disassembly sleeve), please use the appropriate size of the lock nut wrench; If the lock nut is too tight, do not hit the handle of the wrench with the hammer;

5.the use of bearing oiling method, slowly inject oil, when the inner ring along the axial movement, immediately stop the oil; The cone-hole bearing may fly away from the bearing at high speed, and a nut must be installed at the end of the shaft to prevent it from flying away;

6.when using induction heating equipment, do not place flammable materials (such as oil or gas) near the working area; When bearings are used repeatedly or need to be inspected, do not heat more than 120 ° C; Do not touch the heated bearing or surrounding parts without gloves; After heating, remove the bearing (inner ring) from the shaft immediately; If the bearing inner ring is difficult to move during early disassembly, stop the operation, reheat the bearing (inner ring), and then continue the operation.