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Reducer knowledge -- reducer basic structure and lubricating oil inspection and

Modification time:2020-11-24 10:21:25 Hits:

Reducer is mainly composed of transmission parts (gear or worm), shaft, bearing, box and accessories. Its basic structure is composed of three parts:
1. Gear, shaft and bearing combination, pinion and shaft are integrated into one, called gear shaft. This structure is used when the diameter of gear is not related to the diameter of shaft. If the diameter of shaft is D and the diameter of tooth root circle of gear is DF, this structure should be adopted when df-d ≤ 6 ~ 7mn. When df-d > 6 ~ 7mn, the gear and shaft are divided into two parts, such as low speed shaft and big gear. At this time, the gear is connected with the circumferential fixed flat key of the shaft, and the parts on the shaft are fixed axially by the shaft shoulder, shaft sleeve and bearing cover. Deep groove ball bearings are used in both shafts. This combination is used to bear radial load and small axial load. When the axial load is large, the combined structure of angular contact ball bearing, tapered roller bearing or deep groove ball bearing and thrust bearing should be adopted. The bearing is lubricated by using the thin oil splashed when the gear rotates. The lubricating oil in the oil pool of the box seat is splashed off by the rotating gear and splashed on the inner wall of the box cover. After flowing along the inner wall to the groove of the sub box surface, it flows into the bearing through the oil guide groove. When the circumferential speed of oil immersed gear ν ≤ 2m / s, grease should be used to lubricate the bearing. In order to avoid possible splashing oil washing off the grease, oil retaining ring can be used to separate the bearing. In order to prevent the loss of lubricating oil and external dust into the box, a sealing element is installed between the bearing end cover and the extension shaft.
2. Box body is an important component of reducer. It is the base of transmission parts and should have enough strength and rigidity.
The box body is usually made of gray cast iron, and cast steel box can also be used for reducer with heavy load or impact load. In order to simplify the process and reduce the cost, steel plate welded box can be used for single reducer.
Gray cast iron has good casting properties and vibration damping properties. In order to facilitate the installation and disassembly of shafting components, the box body is made into horizontal split type along the axis line. The upper box cover and the lower box body are connected as a whole by bolts. The connecting bolts of the bearing pedestal should be close to the bearing housing hole as far as possible, and the boss beside the bearing seat should have enough bearing surface to place the connecting bolts and ensure the spanner space required for tightening the bolts. In order to ensure that the box has enough rigidity, the supporting rib is added near the bearing hole. In order to ensure the stability of the reducer on the foundation and reduce the machining area of the box base plane as much as possible, the complete plane is not used for the box base.
3. In order to ensure the normal operation of reducer accessories, in addition to paying enough attention to the structural design of gear, shaft, bearing combination and box body, the reasonable selection and design of auxiliary parts and components such as oil injection, oil drainage, oil level inspection, accurate positioning of box cover and box base, hoisting and other auxiliary parts and components should be considered when reducer accessories are in normal operation.
1) Inspection hole to check the meshing condition of transmission parts and inject lubricating oil into the box, the inspection hole should be set at the appropriate position of the box. The inspection hole is set on the top of the upper box cover to directly observe the meshing part of the gear. At ordinary times, the cover plate of the inspection hole is fixed on the box cover with screws.
  2) When the ventilator reducer is working, the temperature in the box rises, the gas expands and the pressure increases. In order to make the hot expansion air in the box be discharged freely, so as to keep the pressure balance inside and outside the box, and not to cause the leakage of lubricating oil along the box surface or shaft extension seal and other gaps, a ventilator is usually installed on the top of the box.
3) The bearing cover is used to fix the axial position of the shafting components and bear the axial load. Both ends of the bearing seat hole are sealed with the bearing cap. The bearing cover has flange type and embedded type. The bearing cover at the extension shaft is a through-hole, in which a sealing device is installed. The advantage of flange bearing cover is that it is convenient to disassemble and adjust the bearing, but compared with the embedded bearing cover, the number of parts is more, the size is larger and the appearance is not smooth.
4) In order to ensure that the accuracy of bearing seat hole manufacturing and processing can be maintained each time the box cover is disassembled and disassembled, the positioning pin should be installed on the connecting flange of the box cover and the box base before finishing the bearing hole. It is placed on the connecting flange on both sides of the longitudinal box, and the symmetrical box should be arranged symmetrically to avoid wrong installation.
5) The oil level indicator is used to check the height of the oil level in the oil pool of the reducer. The oil level indicator is usually installed at the position where the oil level is stable and easy to observe.
6) When replacing the oil with the drain plug, drain the dirty oil and cleaning agent. The oil drain hole should be set at the bottom of the tank seat and the lowest position of the oil pool. The oil drain hole should be blocked by the plug at ordinary times. The sealing gasket should be added between the oil drain plug and the joint surface of the box body.
7) In order to strengthen the sealing effect of the box opening screw, the water glass or sealant is usually applied on the split surface of the box during assembly, so it is difficult to open the cover due to the tight bonding during disassembly. For this reason, two or more screw holes are often machined at the proper position of the connecting flange of the box cover, and the screw with cylindrical or flat end for opening the box is screwed in. Turn the box opening screw to jack up the upper box cover. The small reducer can also be installed without opening screw. When opening the cover, use a driver to pry out the cover. The size of the opening screw can be the same as the flange connecting bolt.
2、 Inspection and maintenance of lubricating oil different lubricating oils shall not be mixed with each other. The position of oil level plug, drain plug and ventilator is determined by the installation position. Their relative positions can be determined by referring to the installation location diagram of the reducer.
1、 Check the oil level, cut off the power supply to prevent electric shock! Wait for the reducer to cool down!
Remove the oil level plug and check whether the oil is full.
Install the oil level plug.
2、 Check the oil, cut off the power supply, prevent electricity! Wait for the reducer to cool down!
Open the drain plug and take the oil sample.
Check the viscosity index of the oil - if the oil is obviously turbid, it is recommended to replace it as soon as possible.
For the reducer with oil level plug - check the oil level, whether it is qualified - install the oil level plug 3. Replace the oil, the viscosity of the oil increases after cooling, and it is difficult to drain the oil. The reducer should change the oil at the operating temperature.
Cut off the power supply to prevent electric shock! Wait until the reducer cools down and there is no danger of combustion!
Attention: the reducer should be kept warm when changing oil!
Place an oil pan under the drain plug.
Open the oil level plug, vent and drain plug.
Drain the oil completely.
Install the drain plug.
Inject new oil of the same brand.
The oil quantity should be consistent with the installation position.
Check the oil level at the oil level plug.
Tighten the oil level plug and ventilator.