Preparation and assembly method of star elastic coupling before operation

XNUMX. Preparing for the operation of the star elastic coupling
　　(1) Operating data: including general installation drawings, component installation drawings, parts drawings, material BOM lists, etc., until the project is completed, the integrity of the drawings, neatness, and completeness of process information records must be ensured.

(2) Workplace: The placement and installation of parts must be carried out in regular workplaces. The placement and installation of the whole machine must be clearly planned until the entire project is completed. All workplaces must be tidy, standardized and orderly. .
　　(3) Installation materials: Before operation, the installation materials according to the installation process rules must be in place on time. If some non-deterministic materials are not in place, the order of operations can be changed, and then fill in the information reminder and submit it to the purchasing department.
　　(4) The structure, installation technology and process requirements of the equipment should be understood before installation.
　　Second, the assembly method of the star-shaped elastic coupling on the shaft
　　Star couplingThe assembly on the shaft is one of the keys to the installation of the coupling.Most of the couplings and shafts are fitted with interference fits. The connection is divided into keyed and keyless connections. The shaft hole of the coupling is divided into two forms: cylindrical shaft hole and tapered shaft hole.The assembly methods include static press-in method, dynamic press-in method, temperature difference assembly method and hydraulic assembly method.
　　1. Static pressure method
　　This method uses clamps, jacks, manual or motorized presses according to the size of the required press-in force during assembly. The static press-in method is generally used for tapered shaft holes.Since the static press-in method is restricted by the pressure machinery, it is difficult to apply a large force when the interference is large.At the same time, the uneven small peaks on the mating surface between the coupling and the shaft will be cut off during the press-in process, causing the mating surface to be damaged.Therefore, this method is generally not widely used.
　　2. Power press-in method
　　This method refers to the use of impact tools or machinery to complete the assembly process, and is generally used where the coupling and shaft fit is transitional or has little interference.At the assembly site, the method of hammering is usually used. The method is to put wooden blocks or other soft materials on the end surface of the wheel hub as a buffer, and rely on the impact force of the hand hammer to knock the coupling in.This method has the risk of local damage to the coupling made of brittle materials such as cast iron, quenched steel, cast alloy, etc., and should not be used.This method will also damage the mating surface, so it is often used for the assembly of low-speed and small couplings.
　　3. Temperature difference assembly method
　　The coupling is heated to expand by heating or the end of the shaft is cold and contracted by cooling, so that the wheel coupling can be easily mounted on the shaft.This method has many advantages compared with the static press-in method and the dynamic press-in method. For the wheel hub made of brittle materials, the temperature difference assembly method is very suitable.
　　The temperature difference assembly method mostly adopts heating method, and the cooling method is less used.There are many heating methods. Some put the wheel hub in high flash point oil for oil bath heating or welding torch baking, and some use an oven to heat it. The assembly site uses oil bath heating and welding torch baking.The high temperature that the oil bath can reach depends on the nature of the oil, and it is generally below 200°C.When other methods are used to heat the hub, the temperature of the coupling can be higher than 200°C, but from the perspective of metallography and heat treatment, the heating temperature of the coupling cannot be increased arbitrarily, and the recrystallization temperature of steel is 430°C.If the heating temperature exceeds 430°C, it will cause changes in the internal structure of the steel, so the upper limit of the heating temperature is less than 430°C.For insurance, the upper limit of heating temperature should be below 400℃.As for the actual heating temperature of the coupling, it can be calculated according to the interference value of the coupling and the shaft and the requirements when the coupling is heated and fitted on the shaft.