This method has the advantages of simple structure and convenient use, and is widely used in reducer.

Figure 1 shows the structure of gear shaft system with external end cover fixed. When leaving the factory, an appropriate amount of axial clearance will be left at both ends to ensure the flexible operation of the bearing and the thermal elongation of shafting parts. The clearance is generally in the range of 0.25 mm ~ 0.4 mm, otherwise the load on the rolling element will be uneven and the axial movement will be serious. Therefore, it is necessary to adjust the bearing clearance to ensure a certain axial clearance. When adjusting the shafting of this fixed way, first open the observation hole of the reducer, and then determine the direction of the shafting movement clearance after checking the meshing condition of the gears.

As shown in Figure 1, if the adjustment clearance at the high-speed axial input side is determined, the blind cover of the high-speed shaft should be removed, and the depth from the bearing to the end cover plane should be measured with a depth vernier caliper and recorded; Then use crowbar tools to move the shafting to the input side, and measure the depth of the bearing at the blind end from the end cover plane. The difference between the two depth dimensions is the amount of bearing movement. After the shafting is moved, add a gasket equal to the displacement on the bearing hole, and finally install the cover.

After all parts are assembled, gently turn the reducer to check whether each shaft rotates flexibly. If there is still jamming, the thickness of the added gasket can be reduced appropriately. Until the rotation of each shaft of the reducer is adjusted flexibly. According to the actual situation, the bearing end cover installed on the box can also be cut, and the cutting depth is the bearing movement or slightly greater than 0.20 mm of the movement. If the cutting depth is greater than 1 / 3 of the plane thickness of the end cover, the end cover needs to be machined again because the end cover is too thin and the strength is weakened.

For the radial thrust bearing with adjustable clearance, the required bearing clearance can be obtained by adjusting the relative position of the outer ring of the bearing. This kind of clearance is generally small to ensure the rigidity of the bearing and reduce noise and vibration. For bearings with non adjustable clearance (such as radial ball bearings), proper clearance can be left between the fixed end cover and the end face of bearing outer ring during assembly to allow thermal elongation of shafting.

In the bevel gear reducer, for the cantilever small bevel gear shafting, it is required to have good rigidity, and the axial position of the shafting can be adjusted to achieve the coincidence of the two gear cone tops. Therefore, the whole shafting is often installed in the collar to form an independent component. The shoulder of the cup is used to fix the bearing, and the shoulder shall not be too high to facilitate the disassembly of the bearing. There are gaskets at the cup flange and the bearing end cover to adjust the bearing clearance and adjust the axial position of the shafting.

When centripetal thrust bearing is used in bevel gear shafting, the bearing can be arranged in two ways: forward installation and reverse installation. The span of the fulcrum is small and the rigidity is poor, but it is convenient to adjust it with gasket. It is inconvenient to install the bearing with reverse mounting structure, and it is troublesome to adjust with round nut, but the span of fulcrum is larger and the rigidity is better. When the arrangement of two bearings is required to be compact and it is necessary to improve the rigidity of shafting, this kind of structure is often used.

2) Bearing clearance adjustment of reducer with embedded end cover

The bearing clearance adjustment is mainly realized by adjusting the end cover of the reducer itself, and there is no need to disassemble the parts of the reducer. The worm bearing clearance of worm gear reducer used in a mine hoist is the adjustment form as shown in Figure 2.

During the production clearance, stop the machine and adjust the bearing clearance of the reducer. If the load at the output end can be discharged, the adjustment will be more accurate. Use the adjusting bolts on the adjusting end cover to adjust. After adjustment, gently turn the reducer to check whether the shafts rotate flexibly. If there is still jamming, it is better to adjust repeatedly until the rotation of each shaft of the reducer is flexible and there is no obvious axial movement.

Due to the interaction of various parts in use, there will be a certain amount of wear on the retaining ring of the fixed bearing outer ring (or inner ring) and the shoulder of the bearing outer ring pressed on the end cover. These insignificant wear will cause a large gap in the shafting and also cause the shafting to move.

It is worth noting that the embedded gland matched with the adjusting bolt (as shown in Fig. 2) has too few contact surface with the bearing outer ring on some reducers (as shown in Fig. 2 before transformation), which often leads to rapid wear and greatly shortens the bearing clearance adjustment cycle. The solution is to increase the contact area between the inner gland and the bearing outer ring (remanufacturing), It can also effectively extend the adjustment period of bearing clearance and prevent bearing damage.

Of course, there are other reasons for the wear of the inner gland, such as the serious wear of the bearing support hole, which destroys the original fit tolerance, resulting in the bearing going to the outer circle (the outer ring rotates with the bearing under the action of friction), etc.

2 One end of the shafting is fixed and the other end swims

The structure of shafting with one end fixed and one end moving is complex, but it can allow large thermal elongation. It is mostly used in shafting with large bearing fulcrum span and high temperature rise. When arranging the support, the end with less radial force should be taken as the swimming end, so as to reduce the friction in the axial swimming. If the radial forces of the two fulcrums are similar, the shaft extension end is often selected as the swimming end.

Figure 3 shows that one end is fixed with a worm shaft system moving at one end. The support of the fixed end is composed of composite bearing. The two rings of the combined bearing are respectively fixed by cup shoulder and bearing end cover. The two inner rings are fixed by the parts on the shaft, the shoulder or the round nut in two directions. Because the bearing of the fixed section bears axial force, the elastic ring is not generally used as the fixing part.

When fixing the inner ring of bearing with round nut, the thread diameter shall be smaller than the bearing inner diameter, the diameter shall be smaller than the gasket size, and the position of gasket in the groove shall be lower than the thread inner diameter (see Fig. 3). When tapered roller bearings are used. In order to prevent the nut from contacting with the bearing cage, a spacer should be added between the nut and the bearing.

The bearing of the swimming end can be centripetal ball bearing or centripetal roller bearing. For centripetal ball bearings, both sides of the inner ring can be fixed by the shaft shoulder and the parts on the shaft, while the outer ring is not fixed. Therefore, axial swimming can be done in the bearing seat hole. For the inner and outer rings of the centripetal roller bearing, it is necessary to fix it. The axial movement of roller is realized by the axial displacement of roller relative to outer ring.

The adjustment of bearing clearance of each shafting system of reducer is very important for stable operation. The following points should be paid attention to when adjusting bearing clearance.

1. The gear engagement must be taken as the basis, and the requirements of contact spots, tooth side clearance and top clearance of two gears shall be met, namely, the speed reducer shall be light and flexible.

2. The bearing clearance must be within the adjustable range. If the bearing clearance is in the scrap state, it is not meaningful to adjust the clearance again.

3. Strengthen the sense of responsibility of operators and spot inspectors, and check the operation at any time; Strengthen the sense of responsibility of maintenance personnel, improve the quality of maintenance and repair, and extend the service life of equipment.