A coupling is a transmitter of rotating energy from one end of a shaft to another. This device is found in most electric motors for the distribution of mechanical energy. There is no universal coupling by design. It can have various shapes and design features.
Device
An electromagnetic clutch, like any other, is a combination of the following parts:
- leading, gathering motor power;
- slave that passes this power on to the regulators.
If these parts are connected without shifting, you will get a permanently connecting part.
Couplings are widely used in the automotive industry, the two main parts of which are connected under the influence of an electric field and a magnetic one.
This makes it possible to connect to the motor without the use of mechanical force, and it also makes it possible to connect in independent positions. Sometimes the electromagnetic clutch allows the regulation of rotational frequencies incontrol system.
Types
Couplings are classified as follows:
- connection of the driven and leading parts is carried out mechanically;
- connection between the main parts is carried out with the help of induction. Such a connection is possible due to the magnetic field.
Mechanical include:
- frictional. The main parts of this clutch are held together by electromagnetic forces. They can be made with a different number of discs and have different friction surfaces (conical or cylindrical);
- powder. In these designs, the driven part is connected to the leading part with a special ferromagnetic powder, which fills the space between the components of the mechanism. This powder is magnetized and holds the pieces together tightly;
- toothed (another name is “cam”). Under the influence of an electromagnet, the main two parts are held together by the teeth located on them.
Induction refers to:
- asynchronous. In this mechanism, due to the rotational movements of the leading part, an electromagnetic effect is formed in the driven part. This part is also called a slip clutch;
- synchronous. Due to the action of permanent magnets at different ends of this part, under the influence of current through the coil, a field appears that holds both parts together;
- hysteresis clutch electromagnetic. As the name implies, the bonding of parts occurs by the phenomenon of hysteresis, when the magnetically solid body is remagnetized.
Any of the above principles of work does not changethe main purpose of the clutch: the transformation of mechanical energy at the input into it at the output.
All types of couplings can be used for control and automatic systems.
The operation of the induction elements corresponds to the operation of the electric motor. Therefore, the following devices are most widely used:
- ferro-powder with electromagnetic control;
- electromagnetic friction clutches.
Ferro-powder with electromagnetic control
For such a part, it is possible to connect parts both rigidly and with slipping of the driven from the leading one.
Due to this, it is possible to adjust the speed of the drive mechanism without interfering with the speed of the drive motor itself.
The structure of the element is as follows. Both parts of the clutch are steel cylinders, which are magnetic cores. In the driven part there is a groove to which the excitation winding is connected. It, in turn, is connected to a power source using slip rings together with a brush. The space between the parts is filled with a ferromagnetic mixture. It can be powdered or liquid.
Working principle
When a constant voltage is applied to the winding, a current is formed, which forms an exciting current. It passes through the ferromagnet and the latter is magnetized, its particles create magnetized chains.
The chains are arranged in the direction of the magneticfield and its lines of force. The resulting force of attraction from the chains and fastens the parts of the coupling. The gripping force depends on the amount of current that flows through the chains. As the current is increased, the material becomes supersaturated, the adhesive force decreases, thus a slip element can be created.
Friction
When there is a force closure in a mechanical connection, then the part can be called a friction or friction clutch. It is possible to connect such a part with engines that are driven under heavy load. Structurally, these elements can be made from one or more disks with different friction surface designs: in the form of a cylinder or a cone.
Working principle
Surfaces subject to friction are connected by an electromagnetic field. It is impossible to regulate the torque of such a friction clutch, it is constant. It is not subject to change under the influence of a change in the magnitude of the current. This clutch can amplify power with a coefficient of more than 30.
Electromagnetic elements are subdivided according to their application.
ETM electromagnetic clutch
Only this part can protect devices and various mechanisms from impulse overloads.
It reduces idle losses. This comprehensively increases the likelihood of starting the engine even at high loads. The electromagnetic coupling is subdivided by design into:
- contactless;
- contact;
- brake.
A/C compressor clutch
It is installed in front of the compressor. It consists of the main elements: a plate, a pulley, an electromagnetic coil.
The plate is attached directly to the shaft, and the coil and pulley are located on the front cover. When the power supply starts, creating a magnetic field, the plate is attracted to the pulley and the compressor shaft starts to move. The pulley rotates together with the plate.
If the electromagnetic clutch is broken, you can repair it yourself.
For a successful repair, you must correctly diagnose the cause of the malfunction. If the compressor clutch breaks, a burning smell and noise can be heard. Usually a knock occurs when a bearing needs to be replaced. There are such malfunctions that only a master can diagnose with special equipment.
If the question arose of replacing such a part as an electromagnetic clutch ("GAZelle" is no exception), then there should be no problems finding the necessary equipment. Well, if the breakdown was discovered in time. This will avoid additional costs in case of failure of other related parts of the engine. Couplings for different equipment are also different, and in order not to make a mistake when buying on your own, you can contact the service center.
If the compressor's electromagnetic clutches fail, the reasons for this may be as follows:
- breakage of the pressure plate when it is incorrectly inserted into the gap;
- the clutch is completely faulty, it can “burn out” and diagnosing the cause of this is very difficult;
- Pulley bearings need to be replaced.
Electromagnetic fan clutch is used in the cooling of car compressors or to maintain a certain engine temperature.
It is also used to maintain the temperature during the cold season, especially if the fan is turned on. It helps reduce fuel consumption by reducing fan drive power.
