Powder coupling. Electromagnetic couplings. Brake technical data

Powder couplings

In continuous servo drives esp. prev powder and hysteresis couplings. They are universal; smooth and intermittent torque control on the drive output shaft is possible. The operating principle of the electromagnetic powder coupling is based on the interaction of magnetic and mechanical forces; the working air gap is filled with ferromagnetic powder, which separates the driving and driven parts of the coupling.

In the absence of current in the control winding of the clutch, the leading part of this clutch rotates together with the armature of the drive motor, and the driven part is stationary. The filler is ferromagnetic powder. When current flows through the clutch control winding, a magnetic flux arises in its magnetic core, the lines of force of which are perpendicular to the forming surfaces of the working gap. Under the influence of this flow, individual particles of the powder are magnetized and interact with other particles, magnetically coupled chains are formed. Many such chains connect the surfaces of the driving and driven parts of the coupling, creating a certain force that prevents the displacement of these parts relative to each other. The magnitude of the force depends on the magnitude of the magnetic induction in the working gap, and the following. and from the current in the clutch control winding. The > this current, the > torque created. coupling. At a certain value of the control current, the clutch magnetic circuit becomes saturated. A further increase in the clutch current does not significantly change the flow in the working gap, and therefore does not lead to an increase in torque.

Moment M 0 caused by particle friction forces. While the load moment< момента, который может передавать муфта, ведомая и ведущая части муфты вращаются синхронно. При нарушении этого условия происходит проскальзывание ведомой части относительно ведущей. Режим скольжения – рабочий режим порошковой муфты в процессе регулирования угловой скорости ведомой части муфты. Скольжение происходит между частицами порошка (в центре рабочего зазора – в середине воздушного зазора). Рабочие поверхности не подвержены износу от трения. Для защиты порошка от механического и химического разрушения, для лучшей теплопроводности ферромагнитный наполнитель кроме основной составляющей (железа) содержит смазывающие компоненты (графит, тальк, mineral oils, kerosene).

Advantages of powder couplings:

1. provides torque limitation on the motor shaft;

2. regulates the speed of rotation of the output shaft with an unregulated engine;

3. high power gain. (Pout up to 400 W, Pcontrol = 1.5..5 W).

Flaws:

1. compared to an adjustable ED, it has a more complex design, big influence heat.

2. limited sliding conditions up to 1200 rpm (the clutch is placed after the gearbox in high-speed engines)

3. instability of the magnetic properties of the powder with changes in ambient temperature and humidity.

Hysteresis coupling.

The operating principle is close to the operating principle of a hysteresis motor, based on the magnetic phenomenon. hysteresis. It consists of a driven part (carries a hysteresis layer made of a material with large specific hysteresis losses), the leading part is an inductor (two or multi-pole magnetic system). In synchronous mode, the torque on the driven shaft is:

where p is the number of pairs of coupling poles

Pr – specific hysteresis losses per 1 magnetization reversal cycle, proportional to the area of ​​the hysteresis loop

Vк – volume of the magnetized layer.

Constancy of the hysteresis moment at variable frequency rotation is the main advantage of hysteresis couplings. Acceleration of the synchronous part to the synchronous frequency – fractions of a second.

The hysteresis coupling does not have the disadvantages of powder couplings. The maximum angular speed of the hysteresis clutch is 5..6 times greater than that of the powder clutch, and the service life is longer. High stability of characteristics. This coupling is often used when the electric drive operates on stops.

The invention relates to the field of mechanical engineering, namely to powder couplings. The powder clutch with the control drive contains a split housing with coaxially mounted shafts on which the drive and driven disks of the coupling halves are rigidly fixed. At the ends of the disks there are several conical grooves and protrusions located concentrically, which interact with each other. The end surfaces of both disks are divided into several sectors by radial depressions. Installed on the driven disk bushing permanent magnet, made in the form of a ring-shaped disk. An electromagnet winding is installed on the drive disk sleeve, the leads of which are brought outside the housing through channels made in the body of the drive shaft and connected to current-collecting rings installed at the output end of the drive shaft, and closed with a cover that is bolted to the housing wall. The current-collecting rings are isolated from the shaft by an insulating sleeve and interact with the current-collecting brushes, which are connected through two conductors to the contacts of a double-pole switch. Opposite contacts of the switch are connected to the source terminals direct current. An adjustable resistor is included in one of the circuits. The technical result is to increase the reliability of the clutch. 4 ill.

Drawings for RF patent 2499923

The invention relates to clutches designed for connecting and disconnecting shafts that transmit torque due to the friction forces between the driving and driven half-couplings and can be used instead of known disk clutches.

Famous powder coupling The clutch contains a split housing with coaxially mounted shafts on which the drive and driven coupling halves are rigidly fixed. At the interacting ends of the disks of the coupling halves there are several conical grooves and protrusions located concentrically. The grooves of the driving half of the coupling are made in the opposite configuration to the protrusions and grooves of the driven half of the coupling. The end surfaces of both coupling halves are divided into several sectors by radial depressions. The depth of the radial depressions corresponds to the depth of the concentric grooves. Friction powder is placed between the discs.

The proposed powder clutch (hereinafter read - powder clutch) differs from the known clutch in that this powder clutch is equipped with an electromagnetic control drive. The coupling body is stationary, and the shafts with the disks of the coupling halves are installed coaxially in the walls of the housing. The driven disk of the half-coupling is equipped with a permanent magnet, made in the form of a ring-shaped disk, installed on the reverse side, and secured to the bushing of the driven disk of the half-coupling. The drive disk of the coupling half is equipped with an electromagnet, the winding of which is also installed on the reverse side of the disk and is secured to the bushing of the drive disk of the coupling half. The leads of the electromagnetic coil pass through channels made in the body of the drive shaft. The ends of the leads are brought outside the housing and connected to current-collecting rings installed at the end of the output shaft, and closed with a cover that is bolted to the wall of the housing. The current-collecting rings interact with current-collecting brushes mounted on the current-collecting ring cover, which are connected through conductors to the contacts of a double-pole switch. The opposite contacts of the switch are connected to the terminals of the DC power supply. IN electrical circuit control, the regulating resistor is turned on.

Figure 1 shows a longitudinal section of a powder clutch.

Figure 2 shows the end surface of the drive half-coupling disk.

Figure 3 shows the end surface of the driven coupling half disk.

Figure 4 shows a longitudinal section of the drive coupling half with electromagnetic circuit management.

The device of a powder clutch with an electromagnetic control drive.

The powder coupling, Fig. 1, contains a split housing 1 and 2, in the cavity of which the driven and driving disks 3 and 4 of the coupling halves are installed. The drive disk 4 is rigidly mounted on the drive shaft 5. The driven disk 3 is mounted on the driven shaft 6. The driven and drive shafts are installed coaxially and secured in the walls of the housing on bearings 7 and 8, which are fixed in the walls of the housing by flanges 9 and 10 and bolts 11. Alignment shafts is provided by a shank 12 made at the inner end of the drive shaft, which interacts with a cylindrical cavity (glass) made at the end of the driven shaft. The surface of the driven shaft is equipped with splines 13, which interact with splines made on inner surface bushings 15 of the driven disk 3. The driven disk has the ability to move along the splines of the driven shaft. A permanent magnet 14, made in the form of a ring-shaped disk, is fixed to the outer surface of the driven disk 3 and the sleeve 15. On the inner end surface of the driven disk 3 there are several conical grooves 30 and projections 16 and 17 (9 pieces), located concentrically. On the drive shaft 5, the drive disk 4 with a sleeve 19 is secured by a key 20. On the outer surface of the sleeve 19, an electromagnet coil 18 is secured, which is equipped with a protective shell 21. On the inner end surface of the drive disk 4 there are several conical grooves 30 and projections 23 and 24 (9 pieces ), located concentrically. The protrusions and grooves of the drive half-clutch disk are made in the opposite configuration to the protrusions and recesses of the driven half-clutch disk, and in such a way that the protrusions of the drive half can fit into the grooves of the driven half-clutch with the possibility of rotation. The drive and driven shafts 5 and 6 are equipped with restrictive rings 25 and 26. Abrasive powder with oily liquid 28 and 29 is placed in the cavity 27 of the housing. Aluminum powder mixed with an oily liquid can be used as an abrasive powder. The oily liquid in this case will perform two functions. In one case, it will provide the bearings with lubricant. Otherwise, this liquid will actively mix the powder and spread it over the entire surface of the disks. Aluminum powder is soft in structure and has plasticity. Getting between the hard protrusions and depressions of the disks, this powder will be smeared over the surface of the protrusions and depressions, thereby creating the necessary conditions for clutching half-clutch discs. The end surfaces of both disks, Figs. 2 and 3, are divided into several sectors by radial depressions 31, evenly distributed around the circumference, the depth of which corresponds to the depth of the concentric grooves 30. In order to eliminate the occurrence of dynamic shocks, in the process of putting the powder coupling into operation, on the disks of the coupling halves done different number radial depressions. On the driving disk there are three radial depressions 31, and on the driven disk there are five radial depressions 31. On the outer circumferential surface of the driven and driving disks there are intake windows 32 and 33. Conclusions 22, Fig. 4, electromagnet coils 18 are output through channels made in the body drive shaft, outside the housing, and are connected to slip rings 34 installed at the end of the output shaft 5. Slip rings 34 are isolated from the shaft by an insulating sleeve 35. The slip rings are closed by a cover 40, which is secured with bolts 11 to the wall of the housing. The current-collecting rings interact with current-collecting brushes 36, which are connected through conductors to the contacts of a two-pole switch P. An adjustable resistor R is included in the electrical circuit, after the switch P, through which you can change the amount of current supplied to the electromagnet coil, which allows you to turn on the coupling in operation with different strengths actions. The opposite contacts of the double-pole switch are connected to the terminals of the power supply. direct current. The drive shaft 5 is equipped with an outer shank 37, with splines, which is used to connect to the motor shaft.

The powder clutch works as follows.

Figure 1 shows the position of the powder clutch in which the half-clutch discs are in a fully engaged state. Since the permanent magnet 14, Fig. 1, has a constant polarity, in order to attract the disks to each other, it is necessary to apply magnetic flux F to disk 4, formed by coil 18, with the opposite polarity, i.e. in this case, it is necessary to supply magnetic flux with the south pole S. To do this, the two-pole switch P is set to the lower position, as shown in Fig.4. The adjustable resistor R motor is set to maximum current supply. The current will flow through the brushes 36 and current rings 34, terminals 22, to the winding of the coil 18. The driving disk 4 will be magnetized, Fig. 4, and along with it the protrusions 23 will be magnetized, which will create a magnetic flux F. The driven disk 3 will be permanently magnetized magnet 14 and will always face the driving disk 4 with the north pole N. The protrusions 16 and 17, which will also have a north pole N. As a result of opposite polarity, attraction will occur between the driving and driven disks 3 and 4. Disk 3 will move along the splines 13 and with its projections 16 and 39, Fig. 3, will enter the depressions 30 of the drive disk, and the projections 23 and 38 of the drive disk will enter the depressions 30 and 31 of the driven disk. Excess trapped liquid between the disks will be forced out through windows 32 and 34 back into the housing cavity 27. Since the powder particles will be larger than the oil film, the powder will be smeared over the surface of the disks and, thereby, will create good condition disks for clutching each other. In addition, when the protrusions 39 of one disk run into the radial depressions 31 and protrusions 38 of the other disk, the volume of the cavities will decrease, and the fluid pressure will increase sharply and cause the driven disk to rotate. In this case, the torque will be transmitted between the disks due to the sliding of the disks. When the disks are fully compressed, rotation will be completely transferred from the drive shaft to the driven shaft.

In order to disconnect the shafts, it is necessary to move the contacts of the two-pole switch P to the upper position. In this case, the polarity of the current in the conductors will change, and a reversal of polarity will occur in the winding of the electromagnet coil 18. The north pole N will be created on the drive disk 4 and protrusions 23. When creating unipolarity on disks 3 and 4, the half-coupling disks will push each other. In this case, the protrusions 16 of the driven disk 3 will begin to be pushed out of the depressions 30 of the drive disk. As a result, the disks will open. The driven disk 3 will move along the splines 13 to the wall 1 of the housing. Shafts 5 and 6 will open from each other and rotation will not be transmitted. The liquid and powder will again be sucked into the cavities between the disks through windows 32 and 33.

You can also change the degree of adhesion between the disks of the coupling halves using resistor R. When the current supply to the electromagnet coil 12 decreases, the force of adhesion of the disks will decrease, and with an increase in the current supply, the adhesion between the disks will increase. When the current is completely turned off, the adhesion of the disks will occur only due to the attractive force of the permanent magnet 14.

CLAIM

Powder clutch with a control drive, containing a split housing with coaxially mounted shafts on which the drive and driven disks of the coupling halves are fixed, on the end surfaces of which there are several grooves and protrusions located concentrically relative to each other, which interact with each other, the end surfaces of both disks divided into several sectors by radial depressions, aluminum powder with oil fluid is placed in the housing cavity, characterized in that the powder clutch is equipped with an electromagnetic control drive, which includes an electromagnet coil winding mounted on the sleeve of the drive disk of the clutch half, a permanent magnet made of a ring shape and secured to the sleeve of the driven disk of the coupling half, the coil winding leads are routed through channels made in the body of the drive shaft, outside the housing and connected to current-collecting rings installed at the output end of the drive shaft, the current-collecting rings are isolated from the shaft with an insulating sleeve and closed with a cover that is secured with bolts to the housing wall, current-collecting rings interact with current-collecting brushes, which are fixed on the cover and connected through conductors to the contacts of a two-pole switch, the opposite contacts of the switch are connected to the terminals of the DC source in one wire circuit, an adjustable resistor is installed between the switch and the brushes.

In the operation of electric drives available in various mechanisms, due to the need for speed, electromagnetic couplings are used. Devices with drive and driven shafts operate due to the fact that an electromagnetic clutch transmits rotation to the elements, causing the mechanism to work. You should know that electromagnetic type coupling connection is an almost exact copy of connections using a hydrodynamic coupling. That is, the scope of application of such a mechanism as electromagnetic couplings corresponds to the area where hydrodynamic analogues are also in demand. For example, when connecting a gearbox and an engine on a ship, it is electromagnetic couplings that are used to transmit torque, as well as to ensure that the vibrations produced by the diesel engine are sufficiently damped.

There are many reasons to use such mechanisms in various devices, since the device fully meets the necessary requirements. The electromagnetic clutch allows you to obtain a gradual, smooth and without jumps transmission of the rotation speed, and also regulates, again, smoothly and without jerks, the transmitted torque. It is precisely because electromagnetic clutches provide smoothness to the entire process, starting from the start of the mechanism, while braking and the necessary change in rotational frequency also occurs gradually and smoothly, leading to the distribution of such an element as the electromagnetic clutch wider than its analogues.

According to the classification, it is possible to describe some differences between the types, for example, electromagnetic powder couplings today are distinguished by true performance. Thus, electromagnetic friction clutches operate almost 15 times slower than a similar powder mechanism, and a hysteretic electromagnetic clutch makes it possible to obtain such characteristics as operating stability and operational durability. At the same time, it is precisely last option– hysteresis couplings – they also differ in that their dimensions are relatively small when compared with the dimensions of other electromagnetic couplings. According to established symbols, the electromechanical properties that one or another electromagnetic coupling shows are designated as MSt -f (Vy). It is these indicators that make it possible to determine what variations occur during the operation of the device, how electromagnetic clutches affect the transmitted torque, and completely depending on how much the current in the winding of a mechanism such as an electromagnetic clutch changes. It is also worth knowing that the residual torque during operation of the mechanism must be significantly lower than the load torque, since otherwise the electromagnetic couplings will rotate the mechanism without any voltage.

3 037 filled with ferromagnetic powder, housing and rotor with magnetic conductors, which have longitudinal grooves increasing the volume of the working element f2: . This coupling is closest to the invention in terms of technical essence and achieved result. This design of the coupling solves very well. the question of increasing the transmitted torque by increasing the amount of ferromagnetic powder. Moreover, the third increase in the amount of the latter does not affect the idle operation of the clutch. Specified positive traits This is ensured by making grooves on the working surfaces of the magnetic cores running parallel to the coupling axis. However, in order to achieve an increase in torque ms by 2-3 times, it is necessary to increase the amount of ferromagnetic powder by more than 4 times. Such an increase requires either deep or wide grooves. Deep grooves are clearly ineffective, since tightening is difficult

f and the formation of full-fledged ligaments that transmit torque. The inefficiency also lies in the fact that it is desirable to direct the magnetic flux completely through the working gaps, and not dissipate it along the magnetic core. In the case of wide grooves, the working surface area of ​​the magnetic cores is not enough to form bundles, i.e. the entire poured amount of powder. As a result, the described coupling design has a slipping value of the coupling halves of 35-40 cm/at

35 transmitted moments of more than 1200 kg/cm. As a result of this amount of slipping, the temperature during this period increases by 25 C. This phenomenon negatively affects the property of the magnetic permeability of the working surfaces of the coupling, which, as is known, are made of soft magnetic material and are sensitive to every degree temperature rise.

The purpose of the invention is to reduce

45 slip and increase magnetic permeability.

For this purpose, additional cavities and radial through slots are made in the side walls of the longitudinal grooves, connecting these cavities with the annular cavity of the coupling filled with powder. In Fig. 1 shows an electromagnetic powder coupling, longitudinal section, Fig. 2 - section AA in Fig. l; in fig. 3 - working surface of the magnetic circuit.

The electromagnetic powder coupling contains concentrically located couplings with an operating gap forming a cavity. .. yuluubufta 2 and 3, the first of them is driven, it is designed to transmit torque through gear 4, installed on the annular surface 5 of its housing 6. In the covers 7 and 8 of the latter, bearings 9 and 10 are mounted. The second half-coupling 3 - driving is a drive shaft 11 installed in bearings 9 and 10 and driven from the primary engine. The rotor is located on the latter

12, in the annular groove of which the excitation winding 13 is fixed. The working parts of the coupling halves are made of soft magnetic material and represent magnetic cores 14. These magnetic cores 14 have longitudinal grooves 15 filled with ferromagnetic powder and additional cavities 16. The latter increase the volume of the powder container and are connected radial through slots 17 with annular cavity 1. Through slots 17 are designed for free exit of powder onto the working surfaces of 18 magnetic cores and for uniform distribution of powder throughout the entire free volume of the annular cavity 1.

The electromagnetic powder clutch works as follows. Drive shaft

11„ IIPIIIIOIIHMII I 0 P IIIeHIIe IIe II HI,I the paagator, rotating in bearings 9 and 10, drags rotor 12 into rotation. In the absence of control current, ferromagnetic powder with the help of additional cavities

16 and slots 17 are evenly distributed over the annular cavity l and the longitudinal groove 15. From the latter, during rotation, the excess part of the powder moves into additional cavities 16. When current is supplied to the excitation winding 12, a magnetic flux arises in the magnetic circuit 14. Its power lines pass along the coupling half 2 through the layer of powder, along the coupling half

3 and again through the layer into half-coupling 2, delighting the closed circuit. At the same time, the ferromagnetic powder located in the grooves 15 and cavities 16 is drawn through the slots

17 onto the working surfaces 18 of the magnetic cores 14. The powder that arrives on the working surfaces “hardens”, engaging with the coupling half 2. As a result of the clutch, the gear 4 rotates at an angular velocity, consistent with the rotation speed of the drive shaft.

Making cavities and through slots on the magnetic cores provides an increase work surface magnetic cores up to

30%, which contributes to the formation of strong bonds from the entire poured amount of powder, and an increase in the speed of formation

Reese. 1 bundles due to the directional and uniform distribution of ferromagnetic powder on the working surface.

These factors ensure a reduction in the relative slippage time of the coupling half by 4.5 times, which, together with a more uniform distribution of powder during idle speed

10 reduces heat generation by more than

2.5 times. Reducing heat generation helps to increase both the properties of the magnetic permeability of the magnetic core material and the service life of the ferromagnetic 1 powder.

Claim

Electromagnetic powder coupling according to the author. St., No. 332263, the main difference is that, in order to reduce sliding and increase magnetic permeability, additional cavities and radial through slots are made in the side walls of the longitudinal grooves, connecting these cavities with the annular coupling cavity filled with powder.

Sources of information taken into account during the examination:

1. G1atetst of France I. 1231768 class R 16 3 37/02, 1960.