Hydraulic Coupler Introduction

Hydraulic coupler, also known as hydraulic coupling, is a kind of used to connect the power source (usually engine or motor) and the working machine, by the change of the liquid torque transmission torque of the hydraulic transmission device, belongs to the hydraulic parts.

The Working Principle of Hydraulic Coupler

Hydraulic coupler is a kind of non-rigid coupling with liquid as the working medium. The pump wheel and turbine of the hydraulic coupler (see figure) form a closed working chamber that enables liquid circulation. The pump wheel is mounted on the input shaft and the turbine is mounted on the output shaft. The two wheels are half rings with many blades arranged in the radial direction. They are coupled towards each other and do not contact each other. There is a gap of 3mm to 4mm in the middle, and a circular working wheel is formed. The driving wheel is called the pump wheel, the driven wheel is called the turbine, and both the pump wheel and the turbine are called the working wheel. After the pump wheel and turbine are assembled, an annular cavity is formed, which is filled with working oil.

The pump wheel usually rotates under the drive of internal combustion engine or motor, and the blade drives the oil. Under the action of centrifugal force, the oil is thrown to the edge of the pump wheel blade. Because the radius of the pump wheel and the turbine is equal, when the speed of the pump wheel is greater than the speed of the turbine, the hydraulic pressure on the outer edge of the pump wheel blade is greater than the hydraulic pressure on the outer edge of the turbine blade. To start spinning a turbine is to transfer kinetic energy to the turbine, causing it to spin in the same direction as the pump wheel. After the kinetic energy drops, the oil flows back from the edge of the turbine blade to the pump wheel, forming a circulation loop, whose flow path is like a circular spiral end to end. The hydraulic coupler transmits torque by the change of dynamic moment generated by the interaction between the liquid and the pump wheel and the turbine blade. The output (turbine) torque is equal to the input (pump wheel) torque when wind damage and other mechanical losses during impeller rotation are ignored.

Classification of Hydraulic Couplers

According to the different uses, hydraulic coupler is divided into ordinary hydraulic coupler, moment limiting hydraulic coupler and speed regulating hydraulic coupler. The torque limiting hydraulic coupler is mainly used for the motor reducer startup protection and impact protection in operation, position compensation and energy buffer; Speed regulating hydraulic coupler is mainly used to adjust the speed ratio of input and output, other functions and moment limiting hydraulic coupler basically the same.

According to the number of working cavities, the hydraulic coupler is divided into single working cavity hydraulic coupler, double working cavity hydraulic coupler and multi-working cavity hydraulic coupler. According to the different blades, the hydraulic coupler is divided into radial blade hydraulic coupler, inclined blade hydraulic coupler and rotary blade hydraulic coupler.

Advantages of Hydraulic Coupler

(1) With flexible transmission automatic adaptation function.

(2) It has the function of shock mitigation and torsional vibration isolation.

(3) It has the ability to improve the starting capacity of the engine, so that it can start with load or no load.

(4) It has overload protection function to protect the motor and the working machine from damage when the external load is overloaded.

(5) It has the function of coordinating the sequential start of multi-engine, balancing load and smooth running.

(6) With flexible braking deceleration function (refers to hydraulic reducer and locked-rotor damping hydraulic coupler).

(7) With the function of delay and slow start of the working machine, can start the large inertia machinery smoothly.

(8) Strong adaptability to the environment, can work in cold, wet, dust, explosion-proof environment.

(9) Inexpensive cage motors can be used instead of expensive winding motors.

(10) No pollution to the environment.

(11) The transmission power is proportional to the square of its input speed. When the input speed is high, the energy capacity is large and the performance-price ratio is high.

(12) With stepless speed regulation function, speed regulating hydraulic coupler can change the output torque and output speed by adjusting the liquid filling amount of the working chamber in operation under the condition that the speed of the input end remains unchanged.

(13) With clutch function, speed regulation type and clutch type hydraulic coupler, can make the working machine start or brake under the condition that the motor does not stop rotating.

(14) With the function of expanding the stable operation range of the engine.

(15) Has the effect of power saving, can reduce the starting current and duration of the motor, reduce the impact on the power grid, reduce the installed capacity of the motor, large inertia difficult to start the mechanical application of moment limiting type hydraulic coupler and centrifugal mechanical application of speed regulating type hydraulic coupler energy-saving effect is significant.

(16) No direct mechanical friction except bearing, oil seal, low failure rate, long service life.

(17) Simple structure, simple operation and maintenance, do not need particularly complex technology, low maintenance costs.

(18) High performance-price ratio, low price, less initial investment, short payback period.