Coupling assembly is the key to the pump, in the mechanical maintenance belongs to a relatively simple maintenance process.
But many are not quite in disc coupling assembly, the key to master the hub in the shaft assembly, coupling connected to the two shafts of the inspection of parts and components and according to the drawing requirements assembly coupling.
Introduction of assembly method of hub on axle.
Hub assembly on the shaft is one of the key coupling installation.
Most of the hub and shaft fit is interference fit, the connection is divided into keyless connection and keyless connection, the hub bore is divided into cylindrical bore and cone bore two forms.
The assembly methods include static compression method, dynamic compression method, temperature difference assembly method and hydraulic assembly method.
This method is different according to the size of the pressing force required for assembly on the hub front axle, and it adopts clamp, jack, manual or motorized press.
Static compaction is generally used for tapered shaft holes.
Due to the static compression method received pressure mechanical limitations.
When the interference is large, it is difficult to apply a large force.
At the same time, in the process of pressing will cut off the hub and shaft between the mating surface uneven small convex peak, so that the mating surface is damaged.
Therefore, this method is generally not applied much.
Bitumen pump assembly this method refers to the use of impact tools or machinery to complete the assembly process on the hub shaft, generally used in the hub and shaft to make the transition between the fit or interference is not big occasions.
The method of hammer beating is usually used in the assembly site. The method is to cushion the end face of the hub with wood blocks, lead blocks or other soft materials as buffer parts.
This method is not suitable for the wheel hubs made of brittle materials such as cast iron, quenched steel and casting alloy, which have the risk of local damage.
This method can also damage the mating surface, so it is often used in the assembly of low speed gear coupling.
Pump assembly with heating method is the hub heating expansion or cooling method to make the shaft cold contraction, so that the inner diameter of the hub shaft hole is slightly larger than the diameter of the shaft end, that is, to achieve the so-called “easy to assemble value”, do not need to apply a lot of force, can easily put the hub set to the shaft.
This method has more advantages than the static pressure method and the dynamic pressure method. For the wheel hubs made of brittle materials, the temperature difference assembly method is very suitable.
Pump assembly temperature difference assembly method mostly adopts the method of heating, cooling method with less.
There are a variety of heating methods, some will be put into the hub of high flash point oil in the oil bath heating or welding gun baking, some use the oven to heat, assembly site more oil bath heating and welding gun baking.
The maximum temperature that an oil bath can reach depends on the nature of the oil and is generally below 200℃.
When the hub is heated by other methods, the temperature of the hub can be higher than 200℃. However, from the perspective of metallography and heat treatment, the heating temperature of the hub cannot be arbitrarily raised, and the recrystallization temperature of steel is 430℃.
If the heating temperature exceeds 430℃, it will cause changes in the internal structure of the steel, so the upper limit of the heating temperature must be less than 430℃.
After the hub of the pump assembly coupling is assembled on the shaft, the verticality and coaxiality of the hub and shaft should be carefully checked.
Generally is in the hub of the end face and the outer circle set two percent meter, turning the shaft rotation, observe the hub of the full run-out (including the end face run-out and radial run-out) value, determine the hub and the shaft of the vertical degree and coaxial degree of the situation.
The requirements for full run-out are different for different speed couplings, and the requirements for full run-out for different types of couplings are also different. However, after the hub is assembled on the shaft, the deviation value of hub full run-out must be within the tolerance range of design requirements, which is one of the main quality requirements for coupling assembly.
