1. Fixed connection:
Fixed connection is becoming increasingly common. In this arrangement, there is no coupling between the pump and the shaft of the motor; the water pump casing is provided with a flange mounting form, and a tight fit clearance is arranged on the motor and the water pump flange. The impeller of the pump is directly mounted on the shaft of the motor. For this arrangement, it should be noted that to ensure that the motor shaft deflection or axial movement plus the tolerance of the machine, not in the pump shell and pump rotor caused contact between. The material of the motor shaft should be adapted to the liquid phase of the pump. If the pump impeller positioning nut, nut thread is the direction of consideration must be given to the direction of rotation of the motor. Unbalanced design of the coaxial connection of the high pressure water pump, can produce high axial thrust, which will be related to the bearing capacity of the motor. In the motor shaft to install some form of water dumped, to prevent leakage of the liquid into the pump seal leakage, which is a fixed connection of the pump is of great practical value.
2. Direct connection:
The pump is often directly connected with the motor. In the water pump and the motor can not be coaxial connection, the vast majority of coupling with the aid of flexible coupling. Using a flexible coupling, allowing the motor and the pump shaft is a little bit of misalignment between the axis (both the axis is included in the included angle or parallel). Some of the old flexible coupling and rigid coupling will produce a large axial load and radial load on the motor bearing. Along with the development of the flexible disc coupling, the early couplings have been eliminated, because the misalignment of the axes will cause serious additional loads. The flexible disc coupling is capable of transmitting very large torques without the need for large dimensions, and only a very small point is generated due to misalignment between the axial and radial loads.
3. Flange type electric motor :
The flange type electric motor can keep the motor and the water pump casing to keep the same, and the connection method is simple and convenient. This structure is usually vertical installation, the motor on the top of the pump, the pump to support the weight of the motor. The pump and the motor shaft are connected by the conventional method, and can also be directly connected. In addition, as a pump connection, this structure should also consider the axial force, if the pump itself does not stop the thrust bearing, the choice of the motor must be considered when the thrust.
As the further development of the flange type electric motor is a vertical hollow shaft motor, the structure with variable length of the hollow sleeve the pump and motor are connected. The pump shaft passes through the center of the hole of the motor shaft, and the torque of the motor is transmitted to the water pump shaft through the shaft coupling of the motor shaft end. Pump shaft and the weight of the impeller, as well as the axial thrust produced by the motor, the bearings are to bear.
