According to the analysis of the "Prospect of the Production and Marketing Demand and Investment Forecast Analysis Report of China's Clutch Manufacturing Industry", clutches are divided into four types: electromagnetic clutches, magnetic particle clutches, friction clutches and hydraulic clutches:
Electromagnetic clutch
The engagement and disengagement of the clutch are controlled by the on/off power of the coil.
Electromagnetic clutches can be divided into: dry single-plate electromagnetic clutch, dry multi-plate electromagnetic clutch, wet multi-plate electromagnetic clutch, magnetic particle clutch, differential electromagnetic clutch, etc.
The working mode of electromagnetic clutch can be divided into: energized combination and power-off combination.
Dry single-piece electromagnetic clutch: when the coil is energized, the magnetic force is generated to attract the "armature" plate, and the clutch is in the engaged state; when the coil is powered off, the "armature" springs back and the clutch is in a disengaged state.
Dry multi-plate, wet multi-plate electromagnetic clutch: the principle is the same as above, in addition to adding a few friction payments, the same volume torque is larger than the dry single-plate electromagnetic clutch, and the wet multi-plate electromagnetic clutch must be cooled by oil or other coolant when working.
Magnetic particle clutch
Place the magnet between the driver and the follower, the magnetic particle is in a loose state when it is not energized, and the magnetic particle is combined when it is energized, and the active part and the driven part rotate at the same time. Advantages: The torque can be adjusted by adjusting the current, allowing for large slippage. Disadvantages: The temperature rise is larger when the slippage is larger, and the relative price is high.
Differential electromagnetic clutch: When the clutch is working, there must be a certain speed difference between the master and slave parts to have torque transmission. The magnitude of the torque depends on the strength of the magnetic field and the difference in rotational speed. The excitation current remains the same and the speed decreases sharply as the torque increases, while the torque remains the same and the excitation current decreases and the speed decreases more severely.
Due to the absence of any mechanical connection between the main and driven parts, no wear and tear, no magnetic particle leakage, no impact, and the speed can be changed by adjusting the excitation current, which is its advantage. The main disadvantage of this clutch is that the vortex currents in the rotor generate heat, which is directly proportional to the speed difference. The efficiency is very low when running at low speed, and the efficiency value is the main speed ratio of the driven shaft, that is, η=n2/n1.
A mechanical drive system suitable for high-frequency operation, which can combine or separate the driven part with the active part when the active part is running.
When the moper and the follower are in a separate state, the mover rotates, and the follower is stationary; the mover and the follower are in the joint state, and the follower rotates between the drive.
It is widely used in machine tools, packaging, printing, textile, light industry, and office equipment.
Electromagnetic clutches are generally used in medium with ambient temperature -20-50 °C, humidity less than 85%, and no explosion hazard, and the coil voltage fluctuation does not exceed ±5% of the rated voltage.
Friction clutch
Friction clutch is the most widely used and the longest history of a type of clutch, which is basically composed of four parts: the active part, the driven part, the pressing mechanism and the control mechanism. The main and driven parts and the hold-down mechanism are the basic structures to ensure that the clutch is in the engaged state and can transmit power, and the control mechanism of the clutch is mainly a device that separates the clutch. During the separation process, the clutch pedal is pressed, and the free clearance of the clutch is first eliminated in the free stroke, and then the separation gap is generated in the working stroke, and the clutch is disengaged. In the process of engagement, gradually loosen the clutch pedal, the pressure plate moves forward under the action of the compression spring, first eliminates the separation gap, and acts enough compressive force on the working surface of the pressure plate, the driven disc and the flywheel;
Hydraulic clutch
Compared with mechanical clutches, hydraulic clutches use fluid (generally oil) as the transmission medium, and in addition to various changes in transmission characteristics, they mainly absorb vibration and shock caused by the rotation of the driving shaft and driven shaft.
The structure of the hydraulic clutch consists of an input shaft with a speed-increasing gear train, a working fluid flow chamber consisting of an impeller, a driven wheel and an impeller housing, an output shaft with a driven wheel and the driven wheel and the impeller can be operated together, and the general impeller housing and impeller are composed of materials with a small specific gravity and a large stress tolerance range to reduce the centrifugal stress.