Electric motor in the form of an external rotor motor

Abstract

Electric motor in the form of an external rotor motor, with a rotor housing (3) and a roller flange (4), wherein the rotor housing (3) and the roller flange (4) are designed to extend coaxially along a rotational axis (6) of the electric motor (1), and wherein the rotor housing (3) has a first locking portion (8) at its first end (5) facing the roller flange (4) and the roller flange (4) has a second locking portion (11) at its third end (10) facing the rotor housing (3), and wherein the first locking portion (8) and the second locking portion (11) are designed to transmit a radial force and an axial force, wherein a first locking element (14) on the first locking section (8) and a second locking element (15, 17) on the second locking section (11) are designed to transmit a radial force in cooperation, and wherein a third locking element (23) on the first locking section (8) and a fourth locking element (24) associated with the third locking element (23) on the second locking section (11) are designed to transmit an axial force in cooperation, wherein the first locking section (8) is tubular, wherein the first locking element (14) is designed in the form of a first surface (14) provided on the inside of the first locking section (8), wherein the second locking element (15, 17) has a second surface (15, 17) of the second locking section (11), which second surface (15, 17) is designed to cooperate with the first surface (14) of the first locking element (14) in such a way that a transmission of radial forces and a coaxial arrangement of the rotor housing (3) and the roller flange (4) is enabled, wherein the third locking element (23) is web-like, extending over a peripheral portion of the first locking section (8), and wherein the fourth locking element (24) has a groove-like recess (26) to enable the third locking element (23) to be at least partially located in the groove-like sides.

Description

[0001] The invention relates to an electric motor in the form of an external rotor motor.

[0002] Electric motors designed as external rotor motors can be used, for example, in transport rollers for transporting packages. For this purpose, the electric motor has a cylindrical drive roller, which is designed to encompass an outer rotor of the electric motor. To securely mount the drive roller on the electric motor, a roller flange is designed, which transmits a torque from the outer rotor to the drive roller. This means that the axial and radial forces occurring between the outer rotor and the roller flange due to a torque from the outer rotor can be safely absorbed by means of a suitably designed connection between the outer rotor and the drive roller. Customers require high accelerations and thus high torques from the drive rollers. For example, a drive roller with a length of 600 mm and a diameter of 50 mm should have an acceleration of 2 m / s. 2 make possible.

[0003] AT 511 630 A1 shows a conveyor roller with a roller shell and an external rotor electric motor. The electric motor has a motor tube and two motor tube supports, over which the motor tube is mounted on dedicated bearings. For non-rotatable mounting, the roller shell is pressed into recesses or grooves in the motor tube.

[0004] CH 297 932 A shows a method for connecting a hollow sheet metal sleeve to an insert.

[0005] JP H03-238 212 A shows a resin housing made of two cylindrical halves. The halves each have projections and recesses and can be assembled and connected with countersunk screws.

[0006] The object of the present invention is to provide an electric motor in the form of an external rotor motor, which realizes a secure power transmission between an external rotor and a drive roller while at the same time being wear-resistant and having low manufacturing costs.

[0007] The object is achieved according to the invention by an electric motor having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the respective subclaims.

[0008] Preferably, the electric motor is designed in the form of an external rotor motor, with a rotor housing and a roller flange, wherein the rotor housing and the roller flange are designed to extend coaxially along a rotational axis of the electric motor, and wherein the rotor housing has a first locking portion at its first end facing the roller flange and the roller flange has a second locking portion at its third end facing the rotor housing, and wherein the first locking portion and the second locking portion are designed to transmit a radial force and an axial force, wherein a first locking element on the first locking portion and a second locking element on the second locking portion are designed to cooperate to transmit a radial force,and wherein a third locking element on the first locking section and a fourth locking element associated with the third locking element on the second locking section are designed to cooperate to transmit an axial force, wherein the first locking section is tubular, wherein the first locking element is designed in the form of a first surface provided on the inside of the locking section, wherein the second locking element has a second surface of the second locking section, which second surface is designed to cooperate with the first surface of the first locking element in such a way that a transmission of radial forces and a coaxial arrangement of the rotor housing and the roller flange is enabled, wherein the third locking element is web-like, extending over a circumferential portion of the first locking section, and wherein the fourth locking element has a groove-like recess,to at least partially accommodate the third locking element in the groove-like recess and thereby prevent movement of the third locking element relative to the fourth locking element at least in one axial direction.

[0009] This means that the first locking section and the second locking section are connected in such a way that the connection is established using two different connection pairs. The connection pairs are designed such that each connection pair is primarily assigned a form of force absorption. A first connection pair is designed as the first locking element and the second locking element and serves to absorb radial forces. A second connection pair, which forms the third locking element and the fourth locking element, serves to absorb axial forces.

[0010] Typically, the goal is to absorb both forces, radial and axial, using a single connection pair. However, the problem is that compromises must be made in the design of the connection pair due to the different forces acting on them, as each force direction requires a specific design. By designing a connection pair to absorb each respective force, the radial or axial force, the corresponding connection pair can be specifically designed to ensure that it can transmit the force to be transmitted reliably, i.e., completely and wear-free over a long operating period.

[0011] The design with the web-like third locking element and the associated groove-like recess allows the web-like third locking element to be pressed into the groove-like recess during assembly, thus enabling axial force transmission between the first locking section and the second locking section. In other words, a clamping tab is formed on the rotor housing, which is pressed from the outside into the groove-like recess of the roller flange. Ideally, a clamping connection is achieved with the help of a slight oversize of the recess and / or the web, which, in addition to receiving the web in the recess, ensures the axial force transmission.

[0012] In one embodiment of the electric motor according to the invention, the second locking element has a plurality of ribs and recesses. For example, the second locking section is at least partially inserted into the first locking section for force transmission, such that the first locking section at least partially encloses the second locking section. The ribs are thus pressed against an inner surface of the first locking section, enabling radial force absorption. The shape with the ribs reduces the contact area and thus facilitates insertion or pressing, which is particularly advantageous for larger dimensions.

[0013] Preferably, the second locking element has a slight oversize, so that play between the first locking element and the second locking element is reduced or eliminated. This achieves zero play or very little play between the first locking element and the second locking element, ensuring the absorption of radial forces. The advantage of this design is that complete absorption of radial forces can be achieved in a simple and therefore cost-effective manner.

[0014] In one embodiment, the fourth locking element has a contact surface that defines the groove-like recess. This contact surface is designed to limit axial movement of the third locking element in at least one axial direction. This enables a defined axial limitation of the axial relative movement between the rotor housing and the roller flange.

[0015] In a further embodiment, the third locking element has a cross-sectional area with an at least partially arcuate contour. This enables cost-effective production of the rotor housing using a deep-drawing process. An outwardly projecting collar is required to hold the rotor housing during deep-drawing. This collar is advantageously placed in the region of the third locking element so that, after the outer part of the collar has been separated, an arcuate contour created by the shaping of the collar remains in this area. The arcuate contour also enables simplified reception of the third locking element in the fourth locking element when it is pressed into the recess.

[0016] Furthermore, the groove-like recess advantageously has a chamfer on an outer edge facing the first locking section, which further simplifies the reception of the third locking element in the groove-like recess and thus facilitates joining. Furthermore, this eliminates play in the axial locking. A chamfer angle in the range of 5° to 30°, preferably 15°, has proven suitable for further simplifying joining and for providing a flat contact surface that is sufficiently large for complete axial force transmission, adjoining the outer edge and extending radially inward.

[0017] In a further embodiment of the electric motor according to the invention, a gap is provided between the inner surface of the third locking element and the fourth locking element after assembly in the entire region of the groove-like recess in order to prevent radial pressure of the third locking element on the fourth locking element. During a joining process of the rotor housing and the roller flange, the third locking element, i.e. the web, is pressed into the recess virtually perpendicular to the axis of rotation. Since damage to a ball bearing positioned in the region of the recess and / or the reduced wall thickness of the roller flange in this region must be avoided, it is advantageous that there is as little contact as possible between the third locking element and the fourth locking element. This is achieved with the help of the gap.

[0018] Preferably, the third locking element is U-shaped after assembly. Pressing the third locking element in during assembly protects the material, and in the event of contact between the third and fourth mounting elements, pressure is applied across a surface rather than a point-like pressure that could cause damage.

[0019] Preferably, the fourth locking element is U-shaped in the circumferential direction. This allows the third locking element to be pressed in with a U-shaped configuration, with a large amount of material still being present in this area to support the side wall of the fourth locking element.

[0020] Transmission of the torque of the rotor housing connected to the roller flange is preferably achieved via a locking pin and a locking receptacle provided on the rotor housing. The pin(s) can also be referred to as an index and prevent the rotor housing from rotating. This is also advantageous in conjunction with the axial securing provided by the web-like third locking element and particularly advantageous in conjunction with the U-shaped design of the third locking element, since the pins free the third locking element from its function of contributing to torque transmission. Rotation of the third and fourth locking elements relative to one another would lead to contact and thus also to a radial force being applied to the fourth locking element.The design with a pin has the advantage of creating a simple and cost-effective connection for torque transmission, since no additional connecting element such as a screw or a clamp is necessary.

[0021] Advantageously, the locking receptacle is formed as a locking recess on the first locking section, with the locking pin extending into the locking receptacle. This allows for simple manufacture of the locking receptacle, and the radial extent of the rotor housing is not increased by the provision of the recess, as would be the case, for example, if the locking receptacle were formed as a bulge.

[0022] In one embodiment, the locking recess is open toward the first end. This allows the roller flange to be pushed into the rotor housing during assembly, as the locking pin(s) can be moved into the locking recess. For example, if a web were provided at the first end of the locking recess, this would have to be pulled outward during assembly.

[0023] Preferably, at least two third locking elements are provided, which are arranged opposite one another to enable the opposing third locking elements to be pressed in from opposite sides during assembly. This arrangement allows the third locking elements to be pressed in from two opposite sides, eliminating the need to apply a counterforce to the rotor housing at another location, which could lead to undesirable deformation at the other location.

[0024] In a further embodiment, the roller flange has a pin-like fixing element designed to enable torque transmission between the roller flange and the drive roller. This enables secure torque transmission and simple assembly.

[0025] The electric motor according to the invention is characterized in particular by its ease of assembly and low manufacturing costs. A secure connection and thus a secure power transmission between the outer rotor and the roller flange is possible without a material connection, such as adhesive bonding, or additional clamping or tensioning devices, such as screws. For example, with a screw connection, there would be a risk of the screws becoming loose due to the possibility of operating the outer rotor in both directions of rotation.

[0026] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as those mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. Identical or functionally equivalent elements are assigned identical reference numerals. For reasons of clarity, it is possible that the elements may not be provided with their reference numerals in all figures, without losing their assignment. They show: Fig. 1 shows a perspective external view of an electric motor according to the invention, Fig. 2 in a first side view a rotor housing and a roller flange of the electric motor according to. Fig. 1 in an unjoined part state, Fig. 3 in the first side view the rotor housing and the roller flange of the electric motor according to. Fig. 1 in a joined part state, Fig. 4 in a second side view the rotor housing and the roller flange of the electric motor according to. Fig. 1 in a joined part state, Fig. 5 in the second side view the rotor housing and the roller flange of the electric motor according to. Fig. 1 in an unjoined part state, Fig. 6 in a perspective external view of the electric motor according to the invention. Fig. 1 with a marking of detail VII, Fig. 7 in a detailed drawing the detail VII of the Fig. 6, Fig. 8 shows a longitudinal section of a section of the electric motor in the region of the first locking section and the second locking section in a first state, Fig. 9 shows a longitudinal section of a section of the electric motor in the region of the first locking section and the second locking section in a second state, Fig. 11 shows a cross-section of the electric motor in the region of the third locking element and the fourth locking element in a first state, Fig. 11 shows a cross-section of the electric motor in the region of the third locking element and the fourth locking element in a second state, Fig. 12 shows a longitudinal section of the electric motor according to the invention, Fig. 13 in a perspective top view of the roller flange and the rotor housing, seen in the direction of arrow I of the Fig. 1 with a marking of detail XIV, Fig. 14 in a detailed drawing the detail XIV of the Fig. 13, Fig. 15 in a plan view of the electric motor according to the invention. Fig. 1, seen in the direction of arrow I of the Fig. 1, Fig. 16 shows a longitudinal section of the electric motor, and Fig. 17. in a three-dimensional representation of the roller flange.

[0027] An electric motor 1 according to the invention in the form of an external rotor motor is according to Fig. 16. The electric motor 1 has an inner stator 46 and an outer rotor 2, which at least partially surrounds the inner stator 46 and has a hollow-cylindrical rotor housing 3. A roller flange 4 for securely receiving and positioning a drive roller 43, which largely surrounds the rotor housing 3, as well as the inner stator 46, is received at a first end 5 of the rotor housing 3. The roller flange 4, which is also hollow-cylindrical, further serves to position the inner stator 46 and to receive a bearing 32 for rotatably supporting the outer rotor 2 about a rotational axis 6 of the electric motor 1. For this purpose, a stationary axle 47 is preferably provided, via which the electric motor is attached to a roller drive system (not shown). A second bearing 35 is preferably provided on a second end 7 of the rotor housing 3, opposite the first end 5, in order to support the outer rotor 2 on the axle 47.The electrical cables for the electric motor 1 (not shown) are led outward, for example, through the interior of the bearing 32, e.g. inside the axle 47 or in the area between the axle 47 and the bearing 32.

[0028] Fig. 1 shows in a first side view the rotor housing 3 and the roller flange 4 in a joined part state, and Fig. 2, accordingly, in an unjoined state. For simplified and precise assembly, and in particular for transmitting a torque of the outer rotor 2 from the rotor housing 3 to the roller flange 4, four locking recesses 9 are groove-shaped in the direction of the rotation axis 6 on a first locking section 8 of the rotor housing 3, which is formed at the first end 5. The locking recesses 9 are positioned around a circumference at the first end 5 such that two locking recesses 9 are opposite each other at a distance of 180°.

[0029] The roller flange 4 has a third end 10 facing the rotor housing 3, a second locking section 11 which is designed for connection to the first locking section 8. In this embodiment, the second locking section 11 can be inserted into the first locking section 8 such that the first locking section 8 predominantly or at least partially covers the second locking section 11, as shown in particular in Fig. 3, in which the rotor housing 3 and the roller flange 4 are depicted in a joined state. For the positive connection, a plurality of locking pins 12, preferably four, are formed on the second locking section 11 at the third end 10 of the roller flange 4, wherein the locking pins 12 are preferably designed to be complementary to the locking recesses 9 in order to enable the locking pins 12 to be received in the locking recesses 9. The locking pins 12 preferably extend axially in the direction of the axis of rotation 6 and are pin-shaped. The locking pins 12 preferably have a slight oversize in order to bring about a press fit together with the locking recesses 9 and to remove play from the relative movement in the circumferential direction that occurs during torque transmission. The oversize also enables a connection with a precise shape and fit, similar to a press fit. This freedom from play orThis reduced clearance is very advantageous for the transmission of torque, also from the point of view of providing a virtually wear-free connection between the rotor housing 3 and the roller flange 4.

[0030] The less play a connection has, the less wear this connection is during operation, since the components forming a connection pair can carry out little to no axial and / or radial and / or tangential movements against each other, for example those that are the basis for abrasion.

[0031] To absorb radial and axial forces, additional locking elements are formed on the first locking section 8 and, correspondingly, on the second locking section 11. The hollow cylindrical or tubular first locking section 8 has a first locking element 14, which corresponds to the first inner surface 14 of the rotor housing 3 in this first locking section 8.

[0032] To absorb the radial forces, at least a second, in Fig. 2 and Fig. 17 is provided, which has a second surface 15, 17 designed to interact with the first surface 14 of the first locking element 14 and to enable a transmission of radial forces as well as a coaxial arrangement of the rotor housing 3 and the roller flange 4. In the broadest sense, one can speak of a tube-in-tube arrangement, whereby the second locking element 15, 17 or the roller flange 4 do not have to be tubular, but can also be closed on the inside. The first locking element 14 and the second locking element 15, 17 can also be used to transmit the torque, particularly in low-power applications. For high torques, however, it is advantageous to relieve the first locking element 14 and the second locking element 15, 17 by providing the locking pins 12.

[0033] Preferably, deformation ribs 15 are provided on the second surface 15, 17, which are positioned distributed over a circumference of the second locking section 11. Recesses 44 are provided at least partially between the deformation ribs 15.

[0034] The deformation ribs 15 are preferably designed with a slight oversize such that when the first locking section 8 and the second locking section 11 are joined, the deformation ribs 15 are pressed against the first inner surface 14, similar to a press fit, so that the radial forces can be absorbed. Likewise, for example, the first locking section 8 could be designed to be receivable in the second locking section 11, such that the first locking element 14 is formed in the form of a first outer surface 16 of the first locking section 8 to absorb the radial forces, with the deformation ribs 15 being positioned on a second inner surface 18 of the second locking section 11.

[0035] The rib-like shape of the second locking element 15 facilitates the assembly of the rotor housing 3 with the roller flange 4, since, in contrast to a second locking element 15 formed completely over a circumference of the inner surface 14, the effort required is lower due to only partial pressing or a reduced pressing surface. Particularly with small dimensions of the electric motor 1, a design without the deformation ribs 15 is also possible. The deformation ribs 15 preferably extend in the axial direction to simplify assembly. The deformation ribs 15 can also have other shapes, e.g., oval, tapered, etc., as long as the contact area between the first locking element 14 and the second locking element 15, 17 is reduced.

[0036] At a fourth end 13 of the roller flange 4 facing away from the second locking section 11, there is preferably at least one fixing element 19 for fixing the Fig. 16 shown drive roller 43, cf. Fig. 17. The drive roller 43 preferably surrounds the rotor housing 3 at least partially or completely. The fixing element 19 is preferably pin-shaped and, for simplified reception of the drive roller 43, has a preferably semicircular contact surface 20 extending in the circumferential direction at its end facing away from the fourth end 13. In its axial extent, the fixing element 19 preferably has a trapezoidal contour 21 starting from its semicircular contact surface 20. Opposite the contact surface 20, a contact shoulder 22 is formed which extends over the entire circumference of the fourth end 13, so that axial displacement of the drive roller 43 via the contact shoulder 22 in the direction of the fourth end 13 is avoided. Two opposing fixing elements 19 are preferably formed for fixing the drive roller 43 to the roller flange 4.A positioning of two fixing elements 19 opposite one another, i.e. offset by 180° over a circumference of the roller flange 4, has proven particularly suitable.

[0037] In Fig. 4 and Fig. 5, the rotor housing 3 and the roller flange 4 are shown in a second side view, wherein this second side view shows the rotor housing 3 and the roller flange 4 rotated 90° about the rotation axis 6 with respect to the first side view, so that a third locking element 23 and a fourth locking element 24 are shown, which are designed to absorb axial forces.

[0038] In Fig. 4, the first locking section 8 and the second locking section 11 are shown in a joined state, wherein, due to an undercut, the fourth locking element 24 is at least partially visible in the joined state, i.e., in the assembled state, in the region of the first locking section 8. The third locking element 23 is web-shaped and, viewed in the axial direction of the rotation axis 6 during assembly, rests against the fourth locking element 24.

[0039] As in Fig. 5, the third locking element 23 is positioned at the first end 5 of the first locking section 8, wherein, to form the web 23, a locking opening 25 completely penetrating a housing wall of the first locking section 8 preferably extends over a predetermined circumferential length of the web 23. The fourth locking element 24 is designed to receive the third locking element 23, i.e. the web 23. It is characterized by a groove-shaped recess 26, which is preferably designed in the second locking section 11 essentially in the axial and circumferential direction to correspond to the web 23 (after assembly), preferably taking an excess dimension into account. The third locking element 23 and / or the fourth locking element 24 can be designed with an excess dimension.

[0040] Through the groove-shaped recess 26, which has a Fig. 8, the fourth locking element 24 is U-shaped or concave. During assembly of the rotor housing 3 and the roller flange 4 in the region of the first locking section 8 and the second locking section 11, the web 23 is at least partially received in the recess 26, wherein the web 23 is pressed or pressed radially into the recess 26 during the assembly process for axial securing. In the process, it partially changes its radial position compared to its radial position before joining. The recess 26 is preferably designed such that a circumferential section of the web 23 is completely received in the recess 26 after assembly, so that the drive roller 43 is positioned in a predetermined position relative to the rotor housing 3. The maximum radial extension Emax is preferably designed to be at least large enough that a circumferential section of the web 23 is completely accommodated in the recess 26.

[0041] Preferably, no locking pin 12 is provided in the angular area on the circumference of the second locking section 11 in which the fourth locking element 24 is provided. For example, in Fig. 17, the angular range of the fourth locking element 24 is from 24' to 24", and it can be seen that the pins 12 are provided in a different angular range of the circumference. This enables an arrangement of the fourth locking element 24 and the pins 12 in a common plane and leads to a smaller axial extension. In addition, the rotor housing 3 is materially weakened in the area of ​​the web-like third locking element, and it is advantageous that this area is not used directly for transmitting the torque.

[0042] In Fig. 7 shows a detailed drawing of the third locking element 23 and the fourth locking element 24 in the assembled state, wherein this illustration particularly shows the position of the third locking element 23 in the recess 26 after assembly. Preferably, two third locking elements 23 and two fourth locking elements 24 are arranged distributed over the circumference of the electric motor according to the invention at a distance of 180°, whereby the third locking elements 23 can be pressed in evenly during assembly, for example, in a pliers-like manner by two opposing pistons of an assembly tool.

[0043] A section of a longitudinal section in the area of ​​the first locking section 8 and the second locking section 11 is shown Fig. 8 and Fig. 9, wherein the third locking element 23 in Fig. 8 before connection with the fourth locking element 24, thus during assembly, and in Fig. 9 in connection, thus after assembly. In Fig. 8, the web 23 is in the extension of the rotor housing 3, and the rotor housing 3 is pushed onto the rotor flange 4, but not yet axially secured. In Fig. 9, the web 23 is received in the recess 26 or pressed into it. The cross-sectional area 27 of the web 23 has a partially arcuate cross-sectional contour 28 on the inside, which, after assembly, is located in the area accommodated in the recess 26. The arcuate cross-sectional contour enables preferred production using a deep-drawing process. The cross-sectional contour can also be rectangular.

[0044] At a contact surface 29 of the recess 26, the cross-sectional contour 28 is designed parallel to the contact surface 29 for the flat contact of the web 23. The contact surface 29 corresponds to a final contact point of the web 23 on the recess 26 after assembly. For simplified and precise reception of the web 23 in the recess 26, a chamfer 30 is preferably formed on an outer edge 31 of the recess 26 facing the first locking section 8 at the contact surface 29 in order to effect axial bracing during assembly. The angle α is preferably in the range of 5° to 30°, particularly preferably it is 15°.

[0045] A first bearing 32 is arranged in the roller flange 4 in the region of the second locking section 11, facing radially toward the rotation axis 6. The first bearing 32 is preferably a rolling bearing, in particular a ball bearing. A housing wall 33 of the second locking section 11 is located between the recess 26 and the first bearing 32. The axial extent of the first bearing 32 and the axial extent of the fourth locking element 24 preferably overlap axially, thus sharing a common axial area. This enables a compact design of the roller flange 4 and thus also of the electric motor 1 in the axial direction.

[0046] To protect the first bearing 32 positioned in the region of the web 23 from damage due to the partial deposition of the web 23 during the assembly process, a safety distance in the form of a gap 34 extending in the axial direction is preferably maintained between the web 23 and the recess 26. This gap 34 is formed in a final position, ie, after completion of the electric motor 1 according to the invention.

[0047] Fig. 10 and Fig. 11 show a cross-sectional section of the electric motor 1 in the area of ​​the third locking element 23 and the fourth locking element 24. In Fig. 10 is the third locking element in its undeformed state, i.e. during or before assembly. Fig. 11, the third locking element 23 has been pressed into the fourth locking element 24, i.e., into the recess, so that it can serve as an axial lock. It can be seen that in this preferred embodiment, the gap 24 extends over the entire area between the radially inner surface of the third locking element 23 and the radially outer surface of the inner wall of the fourth locking element 24. Furthermore, the gap 34 can be additionally secured by so-called press-in dimension specifications.

[0048] The web 23 and the recess 26 can fundamentally enable axial securing in both axial directions, since the web 23 pressed in during assembly would abut the side walls of the recess 26 in both axial directions. However, this axial securing would not be free of play. Therefore, the web 23 and the recess 26 are preferably used to limit axial movement in the direction in which the rotor housing 3 and the roller flange 4 are separated or pulled apart from each other. An axial movement in the opposite direction is preferably limited by the first end 5 of the rotor housing 3 being held against a Fig. 12. This results in a well-defined, large-area connection. Alternatively or additionally, the corresponding axial movement can also be limited by the pin 12 resting against the boundary wall of the locking recess 9, which is remote from the first end 5.

[0049] In Fig. Figure 12 shows the electric motor 1 according to the invention in a longitudinal section. A second bearing 35 in the form of a rolling bearing, in particular a ball bearing, is mounted at the second end 7 of the rotor housing 3. Permanent magnets 36, preferably in the form of bar magnets, are mounted in the rotor housing 3 between the first bearing 32 and the second bearing 35. These bar magnets 36 are preferably fixed to mounting surfaces 37 using an adhesive.

[0050] At the third end 10 of the roller flange 4, radially extending reinforcing ribs 39 are formed, distributed over the circumference of the roller flange 4, cf. Fig. 17. These reinforcing ribs 39 promote a reduction in the material of the roller flange 4 while maintaining dimensional stability.

[0051] Fig. 13 shows in a perspective top view in particular the roller flange 4 connected to the rotor housing 3, seen in the direction of the arrow I of the Fig. 1. On the second inner surface 18, the first bearing 32 is held in the roller flange 4 in a rotationally and motion-proof manner. For this purpose, a support ring 40 is formed on the roller flange 4 between the second inner surface 18 and the second outer surface 17. To reduce the wall thickness W of the support ring 40, and thus to further reduce costs while simultaneously ensuring functional stability of the first bearing 32, reinforcing webs 42 are formed on a third outer surface 41 of the support ring 40, distributed over its circumference, ideally positioned at regular intervals. Fig. 13 marked detail XIV is in Fig. 14, a detailed drawing.

[0052] A plan view of the electric motor according to the invention. Fig. 1, seen in the direction of arrow I of the Fig. 1, is in Fig. 15 to further clarify the features identified and mentioned above.

[0053] The roller flange 4 is preferably made of plastic. The shown design of the roller flange 4 with the various elements for force transmission enables the use of plastic, which is usually less stable than, for example, metal. Furthermore, when plastic is used, the roller flange 4 can preferably be manufactured cost-effectively using an injection molding process. Furthermore, the first bearing 32 can preferably be overmolded directly in the tool using a so-called embedding process, thus eliminating the need for an additional joining process. A metal construction is also possible in principle. The product Durethan BCF 30 X H2.0 901510 from LANXESS Deutschland GmbH, 51369 Leverkusen, Germany, can be used as the plastic, for example. The ISO molding compound designation is "ISO 1874-PA 6,GHR,14-140, (GF+CF)30." The plastic contains 30% glass fibers / carbon fibers, making it a fiber-plastic composite.The plastic is suitable for injection molding, heat stabilized and has improved electrical properties.

[0054] The rotor housing 3 is preferably made of metal, particularly preferably of steel, in order to enable a magnetic return path on the outside of the rotor magnets. The steel used can be, for example, steel with the material number 1.0338, as offered by many manufacturers. It is a cold-rolled sheet and is also referred to as DC 04 LC, i.e. it has the quality DC 04 and is slightly re-rolled. It is an unalloyed steel that is designed for cold forming and is suitable for deep drawing. The rotor housing 3 is particularly preferably produced using the deep drawing process. A drawn tube is also suitable for manufacturing the rotor housing 3. The rotor housing 3 can also be produced using a machining process, e.g. turning or milling, or as a rolled tube.

Claims

[1] Electric motor in the form of an external rotor motor, with a rotor housing (3) and a roller flange (4), wherein the rotor housing (3) and the roller flange (4) are designed to extend coaxially along an axis of rotation (6) of the electric motor (1), and wherein the rotor housing (3) has a first locking section (8) at its first end (5) facing the roller flange (4) and the roller flange (4) has a second locking section (11) at its third end (10) facing the rotor housing (3), and wherein the first locking section (8) and the second locking section (11) are designed to transmit a radial force and an axial force, wherein a first locking element (14) is configured on the first locking section (8) and a second locking element (15, 17) is configured on the second locking section (11) to transmit a radial force in cooperation, and wherein a third locking element (23) is configured on the first locking section (8) and a fourth locking element (24) associated with the third locking element (23) is configured on the second locking section (11) to transmit an axial force in cooperation, wherein the first locking section (8) is tubular in shape, wherein the first locking element (14) is formed in the form of a first surface (14) provided on the inside of the first locking section (8), wherein the second locking element (15, 17) has a second surface (15, 17) of the second locking section (11), which second surface (15, 17) is designed to interact with the first surface (14) of the first locking element (14) in such a way as to enable the transmission of radial forces and a coaxial arrangement of the rotor housing (3) and the roller flange (4), wherein the third locking element (23) is designed as a web extending over a circumferential part of the first locking section (8), and wherein the fourth locking element (24) has a groove-like recess (26) to allow the third locking element (23) to be at least partially inserted into the groove-like side. [2] Electric motor according to claim 1, wherein the second locking element (15, 17) has a plurality of ribs (15) and recesses (44) to facilitate the assembly of the rotor housing (3) with the roller flange (4). [3] Electric motor according to claim 1 or 2, in which the fourth locking element (24) has a contact surface (29) limiting the groove-like recess (26), the contact surface (29) being designed in such a way as to limit an axial movement of the third locking element (23) in at least one axial direction. [4] Electric motor according to claim 3, wherein the third locking element (23) has a cross-sectional area (27) with a cross-sectional contour (28) that is at least partially arc-shaped. [5] Electric motor according to claim 3 or 4, wherein the groove-like recess (26) has a chamfer (30) on an outer edge facing the first locking section (8). [6] Electric motor according to claim 5, wherein the chamfer (30) has an angle which is in the range between 5° and 30°. [7] Electric motor according to one of the preceding claims, in which a gap (34) is provided between the inner surface (28) of the third locking element (23) and the fourth locking element (24) after assembly in the entire area of ​​the groove-like recess (26) in order to avoid radial pressure of the third locking element (23) on the fourth locking element (24). [8] Electric motor according to one of the preceding claims, in which the third locking element (23) is U-shaped after assembly in the area of ​​the fourth locking element (24). [9] Electric motor according to one of the preceding claims, wherein the fourth locking element (24) is U-shaped in the circumferential direction. [10] Electric motor according to one of the preceding claims, in which a locking pin (12) is provided on the second locking section (11) and a locking receptacle (9) associated with the locking pin (12) is provided on the first locking section (8) for receiving the locking pin (12), which together are designed to enable a torque transmission between the rotor housing (3) and the roller flange (4). [11] Electric motor according to claim 10, in which no locking pin (12) is provided in the angular region on the circumference of the second locking section (11) in which the fourth locking element (24) is provided. [12] Electric motor according to one of the preceding claims, in which the locking receptacle (9) is designed as a locking recess on the first locking section (8), wherein the locking pin (12) extends into the locking receptacle (9). [13] Electric motor according to claim 12, in which the locking receptacle (9) is open towards the first end (5) in order to allow the locking pin (12) to be inserted into the locking receptacle (9) during assembly by means of an axial relative movement between the rotor housing (3) and the roller flange (4). [14] Electric motor according to one of the preceding claims, in which at least two third locking elements (23) are provided, which are arranged opposite each other in order to prevent the opposing third locking elements (23) from being pressed in during assembly. [15] Electric motor according to one of the preceding claims, in which a bearing (32) is attached in the roller flange (4), which serves to support the roller flange (4) and the rotor housing (3). [16] Electric motor according to one of the preceding claims, in which the axial extent of the bearing (32) and the axial extent of the fourth locking element (24) overlap axially or are identical. [17] Electric motor according to one of the preceding claims, wherein the roller flange (4) has a contact shoulder (45), and wherein the first end (5) of the rotor housing (3) rests against the contact shoulder (45) in order to prevent movement of the roller flange (4) relative to the rotor housing (3) in at least one axial direction. [18] Electric motor according to one of the preceding claims, wherein the roller flange (4) is made of plastic. [19] Electric motor according to claim 18, wherein the plastic is a fiber-plastic composite. [20] Electric motor according to one of the preceding claims, wherein the rotor housing (3) is made of metal, in particular of steel. [21] Electric motor according to one of the preceding claims, which is connected to a drive roller (43), wherein the roller flange (4) has a pin-like fixing element (19) which is designed to enable torque transmission between the roller flange (4) and the drive roller (43).

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