1. Hydrodynamic coupling
In a liquid as the working medium in a non-positive coupling, also known as the fluid coupling. The pump and the turbine wheel of the hydrodynamic coupling (see above) to form a closed circulating liquid allows working chamber, a pump wheel mounted on the input shaft, a turbine mounted on the output shaft. When
power machine (internal combustion engine, motor or the like) driven by the input shaft, the liquid is thrown out of the centrifugal pump impeller. Such high velocity fluid entering the turbine after the turbine driven to rotate, the energy transmitted from the pump wheel to the output shaft is obtained. Finally, the liquid return pump wheel, a flow of cycle. Hydrodynamic coupling liquid by the pump impeller, the turbine blades interaction momentum changes moment to transmit torque. Its output torque is equal to the input torque by subtracting friction torque, so that output torque is less than the constant input torque. The fluid coupling between the input shaft and the output shaft against liquid contact, there is no rigid connection between the working member.
Characteristics:
Characteristics of the hydrodynamic coupling are: relieving shock and vibration; input rotational speed is lower than the output speed, the rotational speed difference between the two shafts with load increase large increases; overload performance and good starting performance, is too large to load the input shaft is rotated still stopped, without causing damage to the power machine; when the load is reduced, the rotational speed of the output shaft speed increases until close to the input shaft. Hydrodynamic coupling transmission efficiency equal to the output shaft speed multiplied by the output torque (output) by the input shaft speed and the input torque (input power) ratio. Usually the normal condition of the fluid coupling speed higher efficiency can be obtained when the ratio of 0.95 or more. Due to the characteristics of the hydrodynamic coupling working chamber and the pump impeller, the turbine varies shapes are different. As the oil vent fluid coupling, the coupler is in a disengaged state, the clutch can act.
Principle:
A method for coupling a fluid coupling power transmission wheel is not mechanically using two Contact the impeller, it was even powered by hydraulic oilAccess. There are two impellers and supporting force transmission mechanism in the coupler housing is closed, wherein the active referred impeller pump wheel, the other is called a turbine. A radial arrangement with two semi-circular ring of a plurality of blades, which are arranged opposite the coupling, are not in contact, a gap is 3mm to 4mm intermediate and form a ring-shaped impeller. Engine crankshaft driven pump wheel, a turbine associated with the output shaft. The coupler housing is filled with hydraulic oil. When the impeller rotates, the blade drive fluid, the centrifugal force, the oil thrown to the pump vane wheel rim, and impinging on the turbine blades, the turbine starts rotating. In the inertia, of the turbine toward the edge of the fluid into the turbine, and back to the pump wheel rim. Again and again.
Category:
Depending on the application, constant filling of the hydrodynamic coupling into the fluid coupling and a governor-type hydrodynamic coupling. Wherein the constant filling fluid coupling is mainly used for protection and to start operation of the motor reducer of impact protection, energy and position compensation buffer; speed type fluid coupling is mainly used to adjust the input and output rotational speed ratio, other functions and constant filling fluid coupling substantially identical.
limitations:
Time appears earliest hydrodynamic coupling, belonging to the power loss control type (machine) speed. However, as technology advances, the hydrodynamic coupling gradually limitations the following:
1, the hydrodynamic coupling is connected by a mechanical shaft output of the mechanical axis of the hydrodynamic coupling motor; manufactured by change the speed of the fluid coupling connected to the mechanical axis of the fan through the output terminal of the hydrodynamic coupling. Far from the fan and motor, poor efficiency. Need to provide a larger space for installation, complex foundation.
2, since the both ends of the hydrodynamic coupling the two axle shaft, runout large neck, the device will cause leakage in a short time. This will inevitably lead to mechanical shafts and bearings dry grinding. Thus, a higher failure rate.
3, the fluid coupling device belongs to a mechanical governor. Hydrodynamic coupling principle determines the speed of the fluid coupling loss of 8-10 percent. At the same time the power loss becomes heat, so that the hydraulic oil temperature is too high. It requires a large amount of cooling water to cool the hydraulic oil.
4, in the actual operation at temperatures higher than 95 deg.] C or more, the water cooler is easy to plug fouling, resulting in failure.
5, since the hydrodynamic coupling is a hydraulic oil transfer power, speed control is unstable and therefore, low power factor, speed accuracy is poor.
6, when the hydrodynamic coupling failure, the device can only be stopped. Seriously affecting production.
7, a low overall hydrodynamic coupling efficiency, a large loss of the speed itself, maintenance of large, the secondary high cost.
8, fluid coupling loss of power belonging to the controlling speed device, according to the national policy to implement energy and discharge of fluid coupling is not currently product development, production and safety operating cost perspective analysis, the hydrodynamic coupling is not suitable for market use, it will be replaced by another type of power control of an electromagnetic energy-efficient speed control means.