WO1994003960A1

WO1994003960A1 - Electric machine system

Info

Publication number: WO1994003960A1
Application number: PCT/DE1993/000679
Authority: WO
Inventors: Sepp Lachenmaier; Christian Landmark
Original assignee: Sepp Lachenmaier; Christian Landmark
Priority date: 1992-07-30
Filing date: 1993-07-28
Publication date: 1994-02-17
Also published as: DE4225158A1

Abstract

A freely selectable combination of electric machines with various attachments, while observing the safety requirements, is obtained in that the high-load connection (5) for coupling the high-load attachment (1b) and the low-load connection (55) for coupling the low-load attachment (1c) are both fitted on the blind side (2) of the electric machine. The stub (14) of the shaft (6) projecting beyond the bearing (11) on the blind side has, in preparation for a positive connection (5), a driver sleeve (7) which can be fitted over the end of the shaft (6) on the blind side. In order to provide a positive connection (16) integral in rotation, the inside of said sleeve (7) is shaped to fit the stub (14) of the shaft (6) and is integral in rotation on the outside with the hub (8) of the high-load attachment (1b). Said attachment can be, as embodied here, a safety brake. It can also be a free-wheel unit with return stop. The low-load attachment (1c) is here embodied as a fan, but it can also be a tachometer generator or a pulse generator.

Description

Electric machine system

The invention relates to an electrical machine system. It consists of at least three components, namely an electrical machine with a rotating shaft (in particular a motor or generator), a high-load attachment (in particular a brake or a freewheel) and a low-load attachment (in particular a fan). The components of the system are structurally and functionally matched to one another in such a way that they can be combined with one another interchangeably depending on the particular application. A high-load add-on part or a low-load add-on part or both can be attached to the electrical machine at the same time with a rotationally fixed connection to the shaft of the electrical machine. The components do not necessarily have to be manufactured as a closed system by the same manufacturer and offered together. A characteristic of the invention should rather be seen in the fact that the user of the electrical machine system has the required components can assemble each in the required number of pieces for the various purposes.

In electrical machines, a distinction is generally made between a working side and a blind side. The working side is the side on which the shaft protrudes a sufficient distance from the housing for the connection of another machine part. In the case of an engine, this is the output side to which, for example, a transmission or another device or component driven by the engine is connected. In the case of a generator, it is the drive side on which the torque is supplied by the driving machine unit (for example a turbine). The blind side is the side opposite the working side, on which the shaft of the electrical machine usually protrudes only a very short distance beyond the shaft bearing on the blind side. This piece is also referred to below as a wave stub.

Brake motors are a particularly important application of the electric machine system according to the invention. These are units from a motor and a safety brake, which is usually constructed as a disc brake. The hub of the brake disc is connected to the shaft of the motor and rotates with it. In a first type of safety brakes, the brake disk, which is provided with a braking surface on one or both sides, is pushed by an armature disk which can only be moved axially by spring force against a stationary brake bearing plate which is firmly connected to the motor. The brake is released by the supply of energy (for example, electrically or pneumatically), that is to say, for example, when the current is switched on in a brake coil provided in the axial direction beyond the armature disk, the latter is overcome while overcoming the spring force acting in the opposite direction pulled out of the braking position. In the absence of energy supply (switching off the current), the spring presses the anchor plate against the brake disc and this against the brake endshield, whereby the braking effect occurs. Such a brake motor is described, for example, in German Patent Specification 13 03 888. In special applications, in which the safety state of the brake consists of a freely rotatable motor shaft, a second type of safety brake is used, in which the operating mechanism is reversed. These brake with energy supply and release the brake by spring force when there is no energy supply.

Brake motors are generally special motors, which are often derived from other series of electric motors, but the manufacture of which requires a number of special parts. In particular, a shaft which is longer than the normal motor on the blind side is used, which protrudes from the motor bearing on the blind side to such an extent that the hub of the brake disc is connected to it in a rotationally fixed manner and the fan can be attached to the end of the shaft.

This customary design requires considerable logistical effort both for the manufacturer and for the user, because two complete engine series must be kept in stock. If one tries to avoid this by converting the normal motor from the user to a brake motor if necessary, this has hitherto been done by replacing the normal shaft with a longer brake motor special shaft. The exchange of the shaft including the rotor is also associated with considerable effort. However, this effort has previously been considered necessary in order to achieve the high torque that exists between an electrical machine and a high-load attachment (such as a safety brake) must be transferred, thereby ensuring the required safety and enabling the connection of the fan.

The object of the invention is to enable a freely selectable combination of electrical machines with attachments that can be connected on the blind side, one of which is a high-load attachment, such as a safety brake, and the second a low-load attachment, such as a Fan, is. The safety requirements that are to be placed on the connection of electric motors with safety-relevant high-load attachments are to be met in full.

The object is achieved according to the invention by an electrical machine system comprising an electrical machine with a rotating shaft, in particular an electric motor or generator, a high-load attachment with a hub which can be connected in a rotationally fixed manner to the shaft of the electrical machine via a high-load connection, where the high-load connection can transmit at least the maximum torque of the electrical machine, and a low-load attachment which can be connected in a rotationally fixed manner to the shaft of the electrical machine via a low-load connection, the maximum transmitted by the low-load connection in operation Torque is lower than the maximum torque of the electrical machine, in which the high-load connection and the low-load connection are provided on the same blind side of the electrical machine facing away from the working side, the stub of the shaft protruding beyond the blind-side bearing for preparation ng for a positive connection at least over part of its length Has a circular cross-section deviating and the high-load connection includes a driving sleeve which can be pushed onto the blind end of the shaft and which on the inside has a stub of the shaft to produce a form-fitting, rotationally fixed connection with this shape, and on the outside it is non-rotatable with the High-load attachment is connected.

The invention is particularly directed to electrical machine systems with a power range between 10 W and 100 kW, which are produced in large series.

The high-load attachment is preferably a brake, in particular a safety brake of one of the types explained above. These are either in the brake application without spring energy and release by supplying electrical, pneumatic or mechanical energy or the mechanism of action with regard to the energy supply for braking and ventilation is reversed. Another important application is a freewheel with a backstop, such as that used in conveyor belts or ascending conveyors. The rotationally fixed connection of such high-load attachments to the shaft of the electrical machine must be able to transmit at least the maximum torque of the machine. A connection between the shaft of the motor and the hub of the high-load attachment, which is designed for the transmission of a torque which corresponds at least to the maximum torque of the electrical machine, is referred to as a high-load connection.

Like the high-load attachment, the low-load attachment has a rotating element which can be connected to the shaft of the electrical machine. It is preferably a fan. If no high-load attachment to the When the electrical machine is connected, the fan (or another low-load attachment, such as a tachometer generator or pulse generator) is preferably connected directly or with a short axial distance to the shaft end of the electrical machine. If, on the other hand, a high-load attachment is connected to this, the low-load attachment is preferably connected using the low-load connection via an extension shaft that can be connected coaxially to the blind-side stub shaft. The extension shaft can be connected indirectly, for example, by means of non-rotatable fastening to the driving sleeve of the high-load connection. The blind-side end of the shaft of the electrical machine preferably has an axial bore into which the extension shaft can be inserted as a stub shaft with an end adapted to the bore.

In the following, for the sake of simplicity, but without restricting generality, reference is made, for example, to a brake as a high-load attachment and a fan as a low-load attachment.

An essential element of the invention is summarized in the fact that the stub of the motor shaft on the blind side, which usually carries the fan, is prepared for the entire series of electrical machines in the sense of the overall system in such a way that the space of the fan is reduced by the Carrier of the high-load connection can be taken. The motor shaft is thus designed as a normal motor shaft, with the exception that the shaft stub projecting beyond the blind-side shaft bearing is prepared for a positive connection, which is suitable with regard to its construction and dimensions, a positive high-load connection to the brake via a slide-on Manufacture driver sleeve. In the simplest case, the driver sleeve can be formed in one piece with the hub of the high-load add-on part (in the case of the brake with the hub of the brake disc). Preferably, however, the driver sleeve has a shape corresponding to the hub of the high-load attachment on the outside to produce a rotationally fixed connection to the high-load attachment.

The invention enables high-load attachments, for example safety brakes, to be optionally and very easily attached to a motor or generator as system components, the electrical machine being prepared for this without any appreciable additional outlay, but can also be used without the high-load attachment . The high torque is transmitted by the correspondingly dimensioned, relatively short stub in a technically safe manner and without the occurrence of vibrations or vibrations which impair the operation of the electrical machine system. The low-load attachment is connected via a shaft extension, which is neither safety-relevant nor has to transmit high torques. The maximum torque that the electrical machine transmits during operation is in any case less than the maximum torque that can be generated by the electrical machine. As a rule, at most a quarter of the maximum torque of the electrical machine is transmitted via the low-load connection.

The invention avoids the above-mentioned logistical effort on the part of the manufacturer and the user for the parallel provision of different engine variants with and without a safety brake. Overall, this leads to a cost reduction, with additional It should be borne in mind that the brake motor special shaft is a relatively long and thin and therefore in many cases relatively difficult to manufacture expensive turned part.

The invention is explained in more detail below on the basis of an exemplary embodiment shown schematically in the figures; show it:

1 shows a cross section through the blind side of an electric machine system according to the invention with high-load attachment and low-load attachment,

2 shows a cross section corresponding to FIG. 1 only with low-load attachment,

Fig. 3 shows a cross section through a non-attached high-load attachment.

The electrical machine system 1 shown in the figures consists of an electrical machine 1 a in the form of an electric motor 3, a high-load attachment 1 b in the form of a brake 4 and a low-load attachment 1 c in the form of a fan 54.

Only the blind side 2 of the motor 3 is shown, on which only the fan 54 (FIG. 2), only the brake 4 or the brake 4 and the fan 54 (FIG. 1) are optionally and interchangeably attached (adapted) can be. For this purpose, the stub 14 of the motor shaft 6 protruding beyond the blind-side bearing 11 of the shaft 6 of the motor 3 is prepared for a positive connection with a driving sleeve 7, which in turn is rotatably connected to a hub 8 of the high-load attachment part 1b (here the brake disc 21) is connected. In the case shown, the stub 14 has an axially parallel keyway 15. The driver sleeve 7 is provided on the inside with a corresponding feather key 10.

The stub 14, the feather key 16 in connection with the nuts 10 and 15 and the driving sleeve 7 form a high-load connection 5 overall between the motor 3 and the brake 4 (FIG. 1). Instead of the feather key construction, another form-fitting connection can be used, for example a corresponding longitudinal toothing on the outside of the stub 14 and the inside of the driving sleeve 7.

It is essential that the stub 14 at the blind end of the shaft 6 is prepared in terms of its shape and dimensioning in such a way that a positive connection to the hub 8 of the high-load attachment is possible, which is at least necessary for the transmission of the maximum torque of the Electric motor 3 is designed. With regard to the shape, this means that the stub 14 must have a cross section deviating from the circular shape at least over part of its length extending beyond the bearing 11.

As can be seen in the figure, the driving sleeve 7 rests with its first end face 17 against the inner ring of the bearing 11 and with its second end face 18 against a securing ring 19 attached for axially fixing the driving sleeve 7.

As mentioned, the hub 8 of the high-load attachment lb can be firmly connected to the driving sleeve 7. However, an axially movable, rotationally fixed connection between the sleeve 14 and the hub 8 is preferred In this case, the driving sleeve 7 is provided with an external toothing 20 on the outside over part of its length. Corresponding to the external toothing 20 of the driving sleeve 7, the hub 8 of the brake 4 has a corresponding internal toothing 23, whereby there is a positive connection between the driving sleeve 7 and the brake disk 21 in the direction of rotation. The brake disc 21 is displaceable in the axial direction relative to the driving sleeve 7.

In the illustrated case, the brake 4 is a safety disk brake, the brake disk 21 of which can be connected to the shaft 6 in a rotationally fixed manner but axially movably via the hub 8 in the manner described. It carries linings 29, 30 on both sides and runs between two annular friction surfaces, the first friction surface 28 being formed on a braking surface part 27 and the second friction surface 36 on an armature disk 37. The braking surface part 27 surrounds the shaft 6 in a rotationally symmetrical manner and, for centering purposes, is provided on its housing cover side in the region of its outer edge with an annular circumferential shoulder 34 which is raised relative to the housing cover side. This shoulder 34 encompasses the end face 35 of the housing cover 26. The braking surface part 27 is pressed by the screws 45 against the housing cover 26 on the blind side of the electric motor 3 and can additionally be secured against rotation by an anti-rotation device (not shown).

Opposite the second end face 36 of the brake disk 21 facing away from the electric motor 3 is an annular armature disk 37, likewise secured against rotation by screws 45, for braking on the second lining 30 of the brake disk 21. On the surface of the armature disk 37 facing away from the brake disk 21 Helical springs 41 are supported, which are located in recesses 42 of a magnet coil housing 43 of the brake 4 which surrounds the shaft 6 without contact. The coil springs 41 are all at the same distance from the axis of rotation of the shaft 6 and are evenly distributed around the axis of rotation of the shaft 6. Magnetic coils 44 are arranged in the magnetic coil housing 43 around the shaft 6 at an equally but larger distance.

The solenoid housing 43 is clamped to the housing cover 26 by the screws 45 arranged concentrically around the shaft 6, the distance from the axis of rotation of the shaft 6 being greater than the radius of the brake disk 21. For this purpose, the housing cover 26 has a receptacle 46 for the screws 45 threaded holes 47. The magnet coil housing 43 is centered on the braking surface part 27 and thus runs concentrically to the axis of the shaft 6.

The brake 4 is a safety brake which is largely constructed in the usual way and which shows maximum braking action when de-energized. In the unbraked state, the magnet coils 44 release the armature disk 37 from the brake disk 21 counter to the direction of action of the coil springs 41. If the shaft 6 is to be braked or locked, the current supply for the magnet coils 44 is reduced or switched off in accordance with the desired braking effect . This leads to the armature disk 37 being pressed onto the second lining 30 of the brake disk 21 by the coil springs 41. At the same time, the brake disk 21 presses with its first lining 29 onto the braking surface part 27. Thus, the brake disk 21 and thus also the shaft 6 is braked on both linings 29, 30. A special feature in the context of the invention is that the friction surface for the facing 28 facing the motor 3 is either a component of the blind-side housing cover 26 or is provided on a part which is easily rotatably fixed to the surface house cover 26 can be attached. In the case shown, the latter route is chosen. The annular friction surface 28 is formed by a surface of the braking surface parts 27 mounted on the cover 26 in a rotationally fixed manner. This construction is particularly advantageous in those cases in which the cover 26 is made of a material (for example aluminum) which is not suitable for forming a braking friction surface 28 or (for hygiene reasons in the food industry for example) makes special demands on the material of the friction surface 28 are what can be more easily realized if the cover 26 and the braking surface 27 are separate parts.

Insofar as such special features are not to be observed, the blind-side housing cover 26 can be designed directly as a brake end shield and, for this purpose, have an annular friction surface for the linings of the brake disk 21 that is rotationally symmetrical to the shaft 6. In this case, there is no need to separate components 27 and 26.

In order to be able to connect the low-load attachment lc, that is, the fan 54 in the illustrated case, to the shaft 6 in addition to the high-load attachment lb (in the illustrated case, the brake 4), the low-load connection, denoted overall by 55, has one on the Extension-side shaft 51 on the blind-side end 6a of the shaft 6, which can be connected in a rotationally fixed, coaxial manner, for transmitting the torque to the low-load attachment 1c. For this purpose, the blind end 6a of the shaft 6 is preferably provided with a provided axial bore 50 and the extension shaft 51 is a plug-in shaft 52 adapted to be rotatably inserted into this bore 50 with a plug-in part 52a. Since the extension shaft 51 of the low-load connection 55 only has to transmit a small torque, the non-positive fit is a stub shaft sufficient.

In order to be able to connect further low-load attachments (not shown) to the electric motor by means of a further low-load connection, the stub shaft 52 can have a bore 49 at its end on the fan side corresponding to the bore 50 in the stub 14, which is shown in broken lines in FIGS. 1 and 3 is indicated. If necessary, a further stub shaft for transmitting the rotary movement to one or more additional low-load attachments can be inserted into the bore 56.

As can be seen from the comparison of FIGS. 1 and 2, the fan 54 in the illustrated embodiment can be connected to the shaft 6 via two different low-load connections. In the case of FIG. 2 (without a high-load attachment), its hub 53 sits directly on the stub 14 of the shaft 6, the inside of which is designed analogously to the inside of the driving sleeve 7. In the case shown, it thus has a feather key groove 56 corresponding to the groove 10 of the sleeve 7. In this case, a connection which is structurally identical to the high-load connection between motor 3 and brake 4 thus serves as a low-load connection for fan 54. However, in operation it transmits only a low torque and consequently corresponds to the definition of a low-load connection in the sense of the invention. If, on the other hand, as shown in FIG. 1, a high-load attachment part 1b is additionally connected to the same motor without complex conversion measures, a different low-load connection is used, so that the connection variant used in the former case for connecting the high-load Attachment lb becomes available. In the illustrated case, this is the plug connection 50, 52 a.

Since the maximum torque of the electric motor 3 can be introduced into the brake 4 via the high-load connection 5, the entire construction must be designed so that it can withstand the high loads. This includes, in particular, that the stub 14 of the shaft 6, which is primarily subjected to torsion during braking, fulfills certain minimum requirements with regard to the diameter D. Different types of calculation are known to the person skilled in the art for determining the minimum diameter.

Furthermore, the screw connections between the solenoid housing 43 and the housing cover 26 and the housing cover 26 and the housing of the electric motor 3 are to be designed such that they can be loaded with the maximum motor torque.

Claims

Expectations

1. Electrical machine system, comprising an electrical machine (la) with a rotating shaft (6), in particular an electric motor (3) or generator, a high-load attachment (lb) with a hub (8), which is connected via a high-load connection (5 ) can be connected to the shaft (6) of the electrical machine (la) in a rotationally fixed manner, the high-load connection (5) being able to transmit at least the maximum torque of the electrical machine (la), and a low-load add-on part (lc) which is connected via a never derlast connection (55) to the shaft (6) of the electrical machine (3) can be connected in a rotationally fixed manner, the maximum torque transmitted by the low load connection (55) during operation being lower than the maximum torque of the electrical machine ( la), in which the high-load connection (5) and the low-load connection (55) are provided on the same blind side (2) of the electrical machine, facing away from the working side, via the blind-side bearing (11) protruding stub (14) of the shaft (6) in preparation for a positive connection has a cross-section deviating from the circular shape at least over part of its length and the high-load connection (5) has a driving sleeve (7) which can be pushed onto the blind end of the shaft (6) includes, which on the inside has a stub (14) of the shaft (6) for producing a form-fitting, non-rotatable connection with this corresponding shape, and on the outside is connected to the hub 8 of the high-load attachment (lb) in a rotationally fixed manner.

2. Electrical machine system according to claim 1, wherein the driver sleeve (7) for generating the rotationally fixed connection (5) to the high-load attachment (lb) on the outside a form-fitting corresponding to the hub (8) of the high-load attachment (lb) Has.

3. Electric machine system according to claim 1 or 2, wherein the high-load attachment (lb) is a brake (4).

4. Electrical machine system according to claim 3, wherein the brake (4) is a safety brake.

5. Electrical machine system according to claim 3 or 4, in which the blind-side housing cover (26) of the electrical machine as a brake end shield with a flat, to the shaft (6) of the electrical machine rotationally symmetrical annular friction surface (28) for the linings (29) of a brake disc (21) is formed.

6. Electrical machine system according to claim 3 or 4, which includes a braking surface part (27) with an annular friction surface (28) for the linings (29, 30) of a brake disc (21), the blind side The housing cover (26) of the electrical machine is provided with a receptacle (46) for the rotationally fixed mounting of the braking surface part (27) in such a position that the annular friction surface (28) rotates the shaft (6) of the electrical machine in a rotationally symmetrical manner surrounds.

7. The electrical machine system according to claim 1, wherein the high-load attachment (lb) is a freewheel with a backstop.

8. Electrical machine system according to one of the preceding claims, in which the low-load connection (55) has an extension shaft (51) which can be connected non-rotatably and coaxially to the blind-side end of the shaft (6) for transmitting the torque to the low-load attachment part.

9. Electrical machine system according to claim 8, wherein the blind end of the shaft (6) of the electrical machine has an axial bore (50) and the extension shaft (51) is an adapted to the bore (50) in this rotatably insertable stub shaft (52) .

10. Electrical machine system according to one of the preceding claims, in which two different variants of the low-load connection (10, 56, 16; 50, 52 a) are provided for connecting the low-load add-on part (lc), of which the first (10, 56, 16) can be used in applications in which no high-load attachment (lb) is connected, and the second (50,52a) can be used in applications in which a high-load attachment (lb) is connected.