vehicle driveline clutch member is directly linked to the engine, which is responsible for the binding and cutting power and transmission, it is possible to ensure a smooth start when the vehicle is started, but also to ensure smooth shift change is prevented the transmission system overload.
1. clutch Glossary
clutch member is directly linked to the automobile transmission and the engine, which is responsible for the binding and cutting power and transmission, it is possible to ensure that the car started when a smooth start, but also to ensure smooth shift change, the drive train is prevented from overload.
2. Basic introduction clutches
This section describes the clutches vehicle power train assembly member directly linked to the engine
clutch mounted between an engine and a transmission, Yes. Generally installed with the engine crankshaft and the flywheel clutch group, and cutting off the power transmission between the engine and the vehicle drive-train components. The whole process from the start to the normal car driving, the driver may be required to manipulate the clutch, the engine and drive train or temporary separation or gradually engaged to cut off power from the engine to the driveline transmission output. Its role is to enable gradually engaged, thereby ensuring a smooth start between the car engine and the transmission; temporarily breaking the link between the engine and the transmission, and in order to reduce a shift shock when shifting; emergency braking when the vehicle can play separating action, to prevent overloading of the transmission and other drive train, and thus play a protective role.
Clutch similar switch, or break away from engagement by the transmission, therefore, any form of vehicle has a clutch means, just different forms.
3 clutch free
electromagnetic clutch into a clutch, a magnetic powder clutch, hydraulic clutch and friction clutch.
● electromagnetic clutches
off by coils through controlling engagement and disengagement of the clutch.
The electromagnetic clutch can be divided into: dry electromagnetic clutch, a dry multi-plate electromagnetic clutch, a wet multi-plate electromagnetic clutch, magnetic clutch, electromagnetic slip clutch.
electromagnetic clutch operation mode can be divided into: energizing and de-binding binding.
dry electromagnetic clutch: when the coil is energized to produce a magnetic pull “keeper”, clutch in an engaged state; coil power “armature” spring back, the clutch is in the disengaged state.
multi-plate dry, wet multi-plate electromagnetic clutch: principle above, an additional pay several friction, the same volume than dry monolithic electromagnetic clutch torque large, when the oil must wet multi-plate electromagnetic clutch work other liquid or a cooling liquid.
magnetic clutch ●
disposed between the driving and the driven magnetic member, the magnetic powder is not energized in a loose state, the energization when binding the magnetic powder, the active member and the driven member rotate simultaneously. Advantages: the torque can be adjusted by adjusting the current, allowing a larger slip. Disadvantages: large slip large temperature rise, the price is relatively high.
Electromagnetic slip clutch: when the clutch operation, the main, from a portion of a rotational speed difference must exist only torque transmission. Of torque and rotational speed difference depending on the magnetic field strength. Excitation current remains constant, the rotational speed dropped dramatically with increasing torque; torque remains constant, the field current is reduced, reducing the speed even more serious.
electromagnetic clutch slip since the main, between the driven member without any mechanical connection, without wear and tear, no magnetic leakage, no impact speed can be changed to adjust the excitation current, used as a continuously variable transmission, which it is The advantages. The main disadvantage of the clutch rotor eddy currents generate heat which is proportional to the rotational speed difference. Inefficient at low speed, efficiency-based value, the speed ratio of the driven shaft, i.e. η = n2 / n1.
suitable for high frequency operation of the mechanical transmission may be active in a case where the operation portion, the driven portion and the active portion combined or separated. When the state of separation between the
Active member and the driven member, the driving member is rotated, the driven member stationary; engaged state between the drive member and the driven member, the driven member is rotated to bring inter-active.
Widely used in machine tools, packaging, printing, textiles, light industrial, and office equipment.
The electromagnetic clutch for the ambient temperature is generally -20-50 percentage, the percentage of humidity is less than 85, no explosive medium in which the coil voltage fluctuations do not exceed ± 5% of the rated voltage.
Operating principle ● friction clutches
friction clutches
the friction clutch is application of the most widely used is the oldest of a class clutch, consisting essentially of the active part, driven part, clamping mechanism and control mechanism four groups click here to add captions to. Main driven portion and the pressing mechanism is to ensure that the clutch is in an engaged state and to the basic structure of the power transmission, the clutch actuation means so that the clutch mechanism is mainly separated.
4. The clutch of
● ensure the car smooth start
This is the primary function of the clutch. Before the car started, the natural first start the engine. And when the car started, the car is completely stationary state from the gradual acceleration. If the drive train (it links the entire car) rigidly associated with an engine, a transmission is in gear, the car suddenly rushed forward for a moment, but it does not start. This is because when the vehicle is stationary to downfield from, has great inertia, resulting in a large drag torque of the engine. Under the effect of this inertial resistance torque, the engine speed sharply down to the lowest stable (at a rotational speed momentarilyLike 300-500RPM) or less, that is, the engine stalled and can not work, of course, the car can not be started.
Therefore, we need the help of the clutch. After starting the engine, the car before the start, before the driver depresses the clutch pedal, the clutch is disengaged, the engine and drive train is disengaged, then the transmission is in gear, and then gradually release the clutch pedal, the clutch is gradually engaged. In the bonding process, the engine torque is increased gradually hindered, it should also gradually accelerator pedal is depressed, i.e., to gradually increase the fuel supply amount to the engine, the rotational speed of the engine is always maintained at a minimum steady speed, and will not die. Meanwhile, since the tightness of the clutch engagement gradually increases the engine to the drive wheels through the drive train torque will be gradually increased, when the traction force sufficient to overcome the breakaway force, i.e. car accelerates from standstill and gradually moving.
● achieve a smooth shift
In the vehicle is in motion, to adapt to changing driving conditions, driveline often work to replace the different gears. Gear shift type transmission generally toggle gear-gear or other means, to allow a gear pair with a gear drive launched, then make another gear position into the work gear pair. Must be depressed before shifting clutch pedal, interrupt the power transmission, the original facilitates meshing gear disengagement, while the speed of the new gear engaged with the engaging portion of the trend in the sub-synchronization, so that when brought into engagement shock can greatly reduced, thereby achieving smooth shift.
● prevent driveline overload
When the vehicle emergency braking, if no clutch, the engine will vary and drive train is rigidly connected to sharply reduce the rotational speed, and thus wherein all moving parts will have a great moment of inertia (which value may greatly exceed the maximum torque moment during normal engine operation issued), causing the load carrying capacity over its drive train, the mechanical damage. With the clutch, the clutch will be able to rely on the active part and relative motion may arise between the driven part to eliminate this danger. Therefore, we need to limit the maximum torque clutch driveline to bear, in order to ensure safety.
Clutch can be divided into: a friction clutch, or a transmission medium with a liquid (i.e., fluid coupling), or using a magnetic transmission (i.e., an electromagnetic clutch).
5 automobile transmission requirements clutches
The use of the clutch, which should meet the following main requirements:
● engaged smooth and soft to car ensure a smooth start,
● separated quickly and thoroughly, to facilitate the shifting and engine starting;
● having a suitable storage capacity, both to ensure maximum engine torque transmitting driveline can prevent overloading ;
● inertia of the driven gear portion should be as small as possible to reduce the shift shock;
● having good heat dissipation capacity, the car is moving process, when the clutch manipulation frequently , causes the main clutch, slip relative to the driven part, frictional heat is generated, if not shed heat, will seriously affect the reliability and service life of its work;
● control light, to alleviate the driver fatigue.
6. clutch precautions
● installation must be cleaned before the clutch, rust removing grease and debris.
● clutch may be mounted coaxially mounted shaft may be divided, must be fixed axially, the driving part and the driven part are not allowed axial movement, when the sub-shaft is mounted, the driving part and the driven part coaxiality between the shaft should be less than 0.lmm.
● work when wet electromagnetic clutch, the lubricating oil must be added, use of lubrication between the friction plate (1) pouring oil lubrication points; (2) oil bath lubrication, partially immersed in oil of approximately the clutch volume 5 times; (3) the axis of lubricating oil, lubricating method using the high-speed axis and when high-frequency operation.
● electromagnetic clutch when the jaw is mounted, must ensure a gap between the end teeth, so that no idle grinding teeth phenomenon, but not larger than the value of δ.
● electromagnetic clutches and brakes Class B insulation, the normal temperature 40 ℃. When the thermal equilibrium operating temperature limit allowed speeding 100 ℃, otherwise the coil portion and the friction damage easily occurs.
● power and control lines, the clutch 24 volt DC power supply (except for special orders). It is obtained by a three-phase AC voltage or a step-down and full-wave rectifier (or a bridge rectifier), the smoothing and unregulated power demand is large enough. Half-wave rectified power is not permitted.