Time : 2021-01-27 Browse : 28
As a transmission device installed between the engine and the motor, the variable speed hydraulic coupling can convert the electric energy of the motor into liquid kinetic energy, realize soft starting and stepless speed change, improve the starting performance of the motor, enhance the starting capacity, and protect the motor and equipment from overload damage. Although the hydraulic coupling has various structural forms, the basic principles are the same. The following takes the speed-regulating hydraulic coupling as an example to analyze its working principle.
The variable speed fluid coupling is mainly composed of a pump wheel, a turbine, a scoop tube chamber and other components. Its energy transfer process is as follows: When the driving shaft drives the pump wheel to rotate, under the joint action of the blades and chambers inside the pump wheel, the working oil obtains energy and is sent to the outer circumference of the pump wheel under the action of inertial centrifugal force, forming a high-speed oil flow. The high-speed oil flow on the outer circumference of the pump wheel forms a combined speed with the circumferential speed of the pump wheel outlet, rushes into the inlet radial flow channel of the turbine, and drives the turbine to rotate along the radial flow channel of the turbine through the change of the momentum moment of the oil flow.
The oil flows to the turbine outlet, and then forms a combined speed with its radial relative speed and the circumferential speed at the turbine outlet, flows into the radial flow channel of the pump wheel, and regains energy in the pump wheel. This cycle repeats, forming a circulation flow of working oil in the pump wheel and turbine. It can be seen that the pump wheel converts the input mechanical work into the kinetic energy of the oil, and the turbine converts the kinetic energy of the oil into the output mechanical work, thereby realizing power transmission.
The stepless speed change of the speed-regulating turbo coupling is achieved by changing the position of the spoon tube to adjust the amount of working oil in the circulation circle. When the spoon tube is inserted into the deepest part of the hydrodynamic fluid coupling chamber, the amount of oil in the circulation circle is the smallest, the speed deviation between the pump wheel and the turbine is large, and the output speed is the lowest; when the spoon tube is inserted into the shallowest part of the hydraulic coupling chamber, the amount of oil in the circulation circle is the largest, the speed deviation between the pump wheel and the turbine is small, and the output speed is the largest.
