Electric motor with electromagnetically actuated brake and electromagnetically actuated brake for an electric motor

Abstract

Electric motor (50) with an electromagnetically actuated brake, wherein the electric motor (50) comprises a housing, a rotor (1) and a stator (16), wherein the rotor (1) comprises a shaft, a rotor lamination stack and a rotor casting designed as a rotor cage, wherein the shaft (66) is supported in the housing by a fixed bearing (11) and a floating bearing (44), wherein the floating bearing (44) is arranged to be axially movable and the shaft (66) has shaft sections with different diameters, whereby the transitions of the shaft sections form shaft diameter steps, wherein a spring element is arranged axially between the floating bearing (44) and a housing part, namely a bearing shield (42), wherein at least one ring of the floating bearing (44) is pressed against a shaft diameter step by the spring element, wherein the spring element is designed as a disc spring.wherein the brake (550) comprises a magnetic body and a coil mounted in the magnetic body, and a brake control line is provided for controlling the coil, and the brake control line is detachably connected to a coil connection in the magnetic body by means of a brake connector, wherein the brake connector and the coil connection are designed as electrical plug connections, wherein the brake connector has a connector part and the coil connection has a corresponding mating connector part, wherein the connector part is electrically connected by means of the brake control line to a connection option in the terminal box (110) in order to electrically connect the brake control line to an external control electronics or to control electronics located in the terminal box (110), and the mating connector part is electrically connected to the coil.wherein the brake connection line is guided through an eyelet of a bearing shield (42) of the electric motor (50), wherein the brake connection line is strain-relieved by means of a screw connection in the eyelet, wherein the brake (550) comprises a brake pad (169) arranged in a lining area and a tubular brake housing part, wherein the tubular brake housing part has a smaller inner diameter than an outer diameter of the magnet body and the tubular brake housing part is made of an elastic material such that it can be slipped over the magnet body and the tubular brake housing part surrounds the lining area in a housing-forming manner, wherein the tubular brake housing part is made of an elastic material, namely rubber or silicone, which conducts heat less effectively than metal or stainless steel, wherein the brake (550) has a brake pad (169) connected to a shaft (66) of the electric motor (50) in a rotationally fixed manner.The brake pad carrier (168) comprising the brake pad (169) and an armature disk (149) which is fixed against rotation relative to a housing of the electric motor (50), wherein the armature disk (149) and the brake pad carrier (168) are arranged to be axially movable in the pad area, wherein the brake pad carrier (168) comprises two metal disks, namely made of aluminum, which are connected to each other by a damping material and the brake pad (169) is arranged on the metal disks.

Description

The invention relates to an electric motor with an electromagnetically actuated brake and a brake and an electromagnetically actuated brake for an electric motor. An electric motor with a brake is known from DE 198 38 171 A1. This brake has a guide device. The guide device fulfills a variety of tasks and has a relatively complex shape with claws, openings for screws, and shoulders. A bearing shield with a shape complementary to the guide ring is also required. During installation of the brake, a brake connection cable must be routed from the brake to a terminal box of the electric motor. From DE 198 57 950 A1, an electric motor with an integrated, backlash-free, electromagnetically actuated brake is known as the closest prior art. A drive with an electric motor is known from DE 100 29 864 A1. An electric motor with an integrated brake is known from EP 1 011 188 B1. A drive device is known from DE 100 42 106 A1. An electrical machine is known from DE 103 24 621 A1. An electric motor is known from DE 20 2007 009 954 U1. From DE 19 14 469 C2, an adjusting device for the air clearance of a spring-actuated and electromagnetically air-ventilated single-disc brake for motors is known. An electromagnetic brake is known from DE 89 13 767 U1. An electromagnetically actuated brake is known from DE 41 26 672 A1. An electromagnetically actuated brake is known from DE 196 22 983 C1. The invention is therefore based on the objective of further developing an electric motor with a brake, so that the electric motor or the brake can be manufactured and assembled more cost-effectively and easily. According to the invention, the problem is solved in the electric motor according to the features specified in claim 1 and in the brake according to the features specified in claim 2. Important features of the invention for the electric motor with an electromagnetically actuated brake are that the electric motor has a housing, a rotor and a stator, wherein the rotor comprises a shaft, a rotor lamination stack and a rotor casting designed as a rotor cage, wherein the shaft is supported in the housing by a fixed bearing and a floating bearing, wherein the floating bearing is arranged to be axially movable and the shaft has shaft sections with different diameters, whereby the transitions of the shaft sections form shaft diameter steps, wherein a spring element is arranged axially between the floating bearing and a housing part, in particular a bearing shield, wherein at least one ring of the floating bearing is pressed against a shaft diameter step by the spring element, wherein the spring element is designed as a disc spring.wherein the brake comprises a magnetic body and a coil mounted in the magnetic body, and a brake control line is provided for controlling the coil, and the brake control line is detachably connected to a coil connection in the magnetic body by means of a brake connector, wherein the brake connector and the coil connection are designed as electrical plug connections, wherein the brake connector has a connector part and the coil connection has a corresponding mating connector part, wherein the connector part is electrically connected by means of the brake control line to a connection point in the terminal box in order to electrically connect the brake control line to external control electronics or control electronics located in the terminal box, and the mating connector part is electrically connected to the coil, wherein the brake control line is guided through an eyelet of a bearing shield of the electric motor.wherein the brake connection line is strain-relieved by means of a screw connection in the eyelet, wherein the brake comprises a brake pad arranged in a lining area and a tubular brake housing part, wherein the tubular brake housing part has a smaller inner diameter than an outer diameter of the magnet body and the tubular brake housing part is made of an elastic material such that it can be slipped over the magnet body and the tubular brake housing part surrounds the lining area in a housing-forming manner, wherein the tubular brake housing part is made of an elastic material, in particular rubber or silicone, which conducts heat less effectively than metal or stainless steel, wherein the brake comprises a lining carrier having the brake pad and connected non-rotatably to a shaft of the electric motor, and an armature disk that is substantially non-rotatable relative to a housing of the electric motor.The armature disc and the brake pad carrier are arranged to be axially movable in the pad area, the brake pad carrier comprising two metal discs, preferably made of aluminum, which are connected to each other by a damping material, and the brake pad is arranged on the metal discs. An advantage of this design is that the brake can be mounted independently of the rest of the electric motor and is easy to connect to it. Even when replacing the brake, the brake control cable no longer needs to be routed through the rest of the electric motor to the terminal box. The previously used brake control cable can be easily reused. Key features of the invention for the electromagnetically actuated brake for an electric motor are that the brake comprises a magnetic body and a coil mounted within the magnetic body, and that a brake control line is provided for controlling the coil. This brake control line is detachably connected to a coil terminal in the magnetic body by means of a brake connector. An advantage of this design is that the previously used brake control line can be easily reused. This simplifies and speeds up the replacement of a worn or defective brake. According to the invention, the brake connector and the coil connection are designed as electrical plug connections, wherein the brake connector has a plug connector part and the coil connection has a corresponding mating plug connector part, the plug connector part being electrically connected via the brake control line to a connection point in a terminal box of the electric motor in order to electrically connect the brake control line to external control electronics or control electronics located in the terminal box, and the mating plug connector part being electrically connected to the coil. An advantage of this is that the brake is easy to mount and dismount, and that in the mounted state a secure, easily established electrical connection between the brake and the brake control is provided. In a further advantageous embodiment, the brake connection cable is routed from the junction box through the housing of the electric motor to the magnet body. The advantage here is that the brake connection cable is routed safely and protected from external influences. This simplifies and speeds up the installation or replacement of the brake. In a further advantageous embodiment, the brake connection cable is guided through an eyelet in the bearing shield of the electric motor. The advantage here is that the brake connection cable is securely attached to the electric motor and can be mounted easily and precisely. This simplifies the installation and replacement of the brake and ensures a reliable electrical connection between the brake and the brake control system. In a further advantageous embodiment, the brake connection cable is strain-relieved by means of a screw connection in the eyelet. The advantage here is that the brake connection cable is securely held to the electric motor, which simplifies and makes the installation and replacement of the brake safer. In a further advantageous embodiment, the brake comprises a brake pad arranged in a lining area and a tubular brake housing part, wherein the tubular brake housing part has a smaller inner diameter than the outer diameter of the magnet body and is made of an elastic material such that it can be slipped over the magnet body and surrounds the lining area, forming a housing. An advantage of this is that the brake is easy to install and all sensitive parts are protected during installation on the electric motor. Likewise, brake pad debris is reliably contained and does not contaminate the exterior of the brake and / or the electric motor. This, in turn, simplifies and speeds up brake replacement. In a further advantageous embodiment, the tubular brake housing part is made of an elastic material that conducts heat less effectively than metal or stainless steel; in particular, the elastic material comprises rubber or silicone. The advantage here is that the brake is lighter and therefore easier to install or replace. In a further advantageous embodiment, the brake comprises a brake lining carrier, which is non-rotatably connected to a shaft of the electric motor and contains the brake lining, and an armature disk that is essentially non-rotatable relative to a housing of the electric motor, wherein the armature disk and the brake lining carrier are arranged to be axially movable in the lining area. An advantage of this embodiment is that the brake can be pre-assembled, thereby simplifying the installation or replacement of the brake on the electric motor. In a further advantageous embodiment, the brake pad carrier comprises two metal discs, preferably made of aluminum, which are connected to each other by a damping material, and the brake pad is arranged on the metal discs. An advantage of this is that the brake is lighter, thus simplifying the installation or replacement of the brake on the electric motor. In a further advantageous embodiment, the pad carrier and the brake lining are manufactured as a single piece and consist of a single material. The advantage here is that the brake can be manufactured more cost-effectively. In a further advantageous embodiment, the brake is pre-assembled. The advantage here is that the brake can be easily mounted on the electric motor and replaced. Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art. The invention will now be explained in more detail with reference to the figures: Figure 1 schematically shows an electric motor 50 according to the invention in a perspective view. The electric motor 50 has an approximately cylindrical stator housing 52 with cooling fins 54 arranged parallel to each other and projecting approximately radially from the stator housing. The free ends of the cooling fins 54 lie approximately in a flat contact surface, in particular in four flat contact surfaces arranged approximately at right angles to each other. Trapezoidal ridges 49 at the end faces of the outer surfaces of the stator housing 52 form corner elements between the flat contact surfaces. The outer surfaces of the outermost cooling fins 54 of the contact surfaces are connected to each other via a thickening in the stator housing 52 that forms an isosceles right angle.In at least one of the flat contact surfaces, a blind-hole-like mounting bore 60 with an internal thread is provided in a thickening connecting several cooling fins 54. This mounting bore 60 serves as a fastening point for various attachments, such as a ring bolt 24, which in turn allows the electric motor 50 to be attached to a crane hook. A foot 90 is attached to the stator housing 52. A cuboid terminal box 110 is screwed onto a terminal box base 67 provided for this purpose. The terminal box base 67 is formed integrally with the stator housing 52 and projects along the cooling fins 54 in an approximately radial direction beyond the free ends of the cooling fins 54. The terminal box 110 has a terminal box base 112 and a terminal box cover 132, which is screwed to the terminal box base 112 by means of a terminal box hexagon screw 123. The housing of the electric motor 50 comprises a flange plate 64, a bearing plate 42, and the stator housing 52. The end faces of the stator housing 52 are closed by the bearing plate 42 and the flange plate 64, except for a passage for a shaft 66 in the flange plate 64 and a shaft passage in the bearing plate 42. A flange 7 for attaching driven devices is integrally formed on the flange plate 64. For this purpose, the flange 7 has a flange bore 8 through which suitable screws can be inserted. A cylinder screw 19 is guided through bores in the bearing shield 42 and bores in the trapezoidal ridges 49 on the stator housing 52 and screwed into a hexagonal nut 17, thus securing the bearing shield 42 to the stator housing 52. A hexagonal screw 15, guided through a through-hole in a trapezoidal ridge 49 on the flange shield side of the stator housing 52 and supported by a washer 14, is screwed into an internal thread of a bore in a trapezoidal ridge on the flange shield 64. In this way, the flange shield 64 and the bearing shield 42 are pressed against the end faces of the stator housing 52 in a rotationally fixed manner. A fan hood 35 is attached to the circumference of the bearing shield 42, or rather, partially overlapping the bearing shield 42 in the axial direction, and fastened to the bearing shield 42 with further hexagonal screws 22. A circumferential wall of the fan hood 35 has a first section parallel to the axial direction of the shaft 66 and a second section that slopes inwards in a funnel shape relative to the axial direction of the shaft 66. The first section has a subsection on the stator housing side with a circumference suitable for partially overlapping and fitting onto the bearing shield 42. The first subsection transitions towards the base of the fan housing 35 into a second subsection with a reduced circumference due to a step. L-shaped recesses are arranged in the wall sections of the rounded corners of the first subsection on the stator housing side. These recesses allow the fan housing 35 to be snapped into the additional hexagonal screws 22 attached to the bearing shield 42. The fan housing 35 is then secured to the bearing shield 42 by tightening these additional hexagonal screws 22. Further C-shaped recesses extend around the L-shaped recesses and reduce the transmission of vibrations from the electric motor 50 to the fan housing 35.A ventilation threaded pin 164 protrudes from an elongated hole in a rounded corner area of ​​the second subsection, to which a hand lever 51 can be screwed. The second section of the fan hood 35 has approximately wave-shaped elevations and depressions in the sections which, in the assembled state, are designed as a continuation of the flat bearing surfaces of the stator housing 52. Fig. 2 schematically shows the electric motor 50 according to the invention shown in Fig. 1 in a perspective exploded view, wherein the electric motor 50 is additionally provided with a protective roof 705. The rotor 1 comprises a shaft 66 and a rotor assembly 72. The shaft 66 has several shaft sections with different diameters in the axial direction. Due to the different diameters, the transitions between the shaft sections form several shaft diameter steps. The rotor assembly 72 is arranged in a rotationally fixed position approximately centrally on the shaft 66 in the shaft section with the largest shaft diameter, in particular by being pressed onto this shaft section. A fixed bearing 11, designed as a deep groove ball bearing, is mounted on the flange end of the shaft 66. An inner ring of the fixed bearing 11 is axially fixed on the shaft side by a retaining ring 10 with a support washer 104 and a shaft diameter step. On the end shield side, a floating bearing 44, also designed as a deep groove ball bearing, is mounted on the shaft 66 up to a further shaft diameter step. A spring element 41 is designed as an annular spring element, preferably as a disc spring. The floating bearing 44 is movably fixed in a bearing receptacle in the end shield 42 between the further shaft diameter step and the spring element 41. It is movably fixed in the sense that the floating bearing 44 can follow axial displacements of the further shaft diameter step due to a change in the length of the shaft 66. The spring element 41 springs accordingly without deforming the floating bearing 44 or adversely altering its bearing properties.In this way, for example, thermally induced length changes of the shaft 66 or manufacturing tolerances of the shaft 66 and the bearing housing are recorded. A driver 70 is rotationally fixed to the shaft 66 by a driver key 71, which can be inserted into a corresponding keyway in the shaft 66, for example by friction fit and / or, in particular, by positive fit. Axially, the driver 70 lies between the floating bearing 42, or the spring element 41, and a retaining ring 62 for the driver 70. The driver 70 is designed as a cylindrical gear, with a toothed ring formed only on a brake-side section of the driver 70. On the bearing shield side, the driver has a circumferential ring, which is spaced apart from the toothed ring by a circumferential groove. In a bearing shield-side end section of the shaft 66, a fan wheel 36 is attached to the shaft 66 in a rotationally fixed manner, in particular by positive locking, such as with a flattening in the shaft cross-section or a fan wheel key 31. In the axial direction, the fan wheel 36 is fixed by an additional shaft diameter step and a further retaining ring 32 by positive locking and / or friction locking. An interior of the housing is protected from contaminants such as dust, water, and / or gear oil by a splash guard 107 and a shaft seal 106 in the opening for the shaft 66 in the flange shield 64. A driven device can be flanged to the flange 7 using stud bolts 103 and flange hexagon nuts 100. A rotating part of this driven device can be fixed against rotation, in particular by means of a positive-locking connection to the shaft 66 using the key 3. A sealing screw 9 is used to close an oil inlet opening. If a gearbox is directly flanged to the flange 7, gearbox oil can be supplied or exchanged via this oil inlet opening. The fixed bearing 11 is fixed on the stator housing side by the flange shield 64 and a retaining ring for bores 12. A stator 16 comprises a stator lamination stack 18 and a stator winding 20 with a winding head 21 and is mounted in the stator housing 52. A foot 90 is attached to the stator housing 52 by a foot screw 94, a foot washer 93, and a foot hexagon nut 91. A terminal plate 115 is attached to the terminal box base 67 by means of a further screw 113. The terminal plate 115 has at least one threaded rod designed as a connecting bolt with a nut and washer that can be screwed onto the threaded rod. In the stator housing 52, in the area of ​​the terminal box base 67, there are cable glands for intended connecting leads, such as connecting leads for the stator winding 20. An inner corner of the terminal box base 67 is reinforced in an approximately cylindrical shape. A blind hole with an internal thread is machined into this reinforcement. The terminal box lower part 112 is screwed to the terminal box base 67 in these reinforcements by means of fastening screws 119. A seal 111 for the terminal box lower part 112 is clamped between the terminal box lower part 112 and the terminal box base 67.Cable glands of various sizes are located in one wall of the junction box base 112. These glands can be closed using appropriately sized sealing screws 129 and 134 with O-rings. Alternatively, a brake relay can be screwed into such a cable gland using a reducer 96, with its connecting cable protruding into the junction box. The brake relay is used to control a brake 550 for the electric motor. Other components, such as cable clamps or rectifiers, can also be screwed onto the cable gland. The terminal box base 112 projects beyond the terminal box base 67 and the bearing plate 42 on the bearing plate side within a terminal box area, forming a base plate in this area. Various clamping devices, in particular a terminal strip 153, are located on this base plate, projecting into the interior of the terminal box base 112. The terminal strip 153 is arranged on a brake connection part 136. The terminal strip 153 and the brake connection part 136 have lateral, superimposed eyelets through which a brake connection part screw 137 is guided, which is screwed to the base plate of the terminal box base 112. A connecting clamp 262 and another connecting clamp 615 are mounted on a mounting plate 616. The mounting plate 616 is fastened in the terminal box 110 by means of a fastening screw 137. Furthermore, a cuboid extension projects from the base plate into the interior of the terminal box 110. A clamping threaded rod 117 is screwed into this extension. A clamping nut 219 is screwed onto the clamping threaded rod 117, allowing a spring washer 118 and a clamping washer 116 to be pressed onto the extension. Towards the terminal box base 67, the terminal box lower part 112 forms a frame corresponding to an end face of the terminal box base 67. A seal 111 for the terminal box lower part 112 is clamped between the frame and the end face. Through holes for fastening screws 119 are located in the four corners of the frame for attaching the terminal box lower part 112 to the terminal box base 67. A fan washer 128 and an outer washer 140 are attached to an outer wall of the terminal box lower part 112 with an outer screw 139. The terminal plate 115 and the various clamping devices are used for the electrical connection of externally supplied lines to the lines supplied from the electric motor 50 into the terminal box 110, such as the lines supplied from the stator winding 20. A warning label 156 is located inside the terminal box 110. The terminal box 110 is closed with a terminal box cover 132 and a seal 131 for the terminal box cover 132, which is clamped between the terminal box cover 132 and the terminal box base 112. For this purpose, the terminal box cover 132 is screwed to the terminal box base 112 with the terminal box hexagon screws 123. A nameplate 108 is attached to one of the flat mounting surfaces by means of a notched nail 109. The nameplate 108 bears the technically relevant parameters as well as the product designation for the electric motor 50. In a circumferential area of ​​the bearing shield 42 facing the terminal box 110, an eyelet with a receptacle for an O-ring 390 is formed. This serves as a feedthrough to a corresponding opening in the terminal box 110 for connecting cables of various optional components that can be attached to the electric motor 50, such as the access cables of the brake 550. The O-ring 390 seals the connection between the terminal box 110 and the bearing shield 42. A screw connection 418 provides strain relief for the connecting cables in the eyelet. The bearing shield 42 forms a thickening in the area of ​​the shaft passage. This thickening is shaped towards the stator housing 52. A hollow cylinder, completely open towards the stator housing, within the thickening of the bearing shield 42 is shaped concentrically with a larger diameter than the shaft passage and forms a cylindrical bearing receptacle for the floating bearing 44. Since an outer ring and an inner ring of the fixed bearing 11 are axially fixed, the floating bearing 44 does not have to absorb any axial forces acting on the shaft 66 from the outside. Therefore, the floating bearing can be dimensioned as a smaller bearing, and the electric motor is more compact. A thickened outer edge of the bearing shield 42 is also formed towards the stator housing 52. A thickening is also formed on the outer edge of the bearing shield 42, which has a through bore aligned parallel to the shaft 66 and a blind bore with internal thread arranged perpendicular to it and extending radially to the shaft 66. The blind bore with internal thread extending radially to the shaft 66 serves to fasten the additional hexagon head screws 22, whereas the socket head cap screws are guided through the axially extending bores. A brake 550 is screwed onto the bearing plate 42 using brake mounting screws 900. The brake 550 comprises a brake shield 702, a lining carrier 168, an approximately tubular brake housing part 166, and a magnet body 154, as well as other parts, which are assembled using a brake mounting screw 160 and a brake mounting nut 161. This assembly takes place independently of the rest of the electric motor 50 and before the brake 550 is installed. It is therefore a pre-assembled brake 550. The pre-assembled brake 550 is completely placed onto the drive 70 or onto the shaft 66, whereby the brake 550 is first engaged and then screwed into place by gently rotating the shaft 66 or the pre-assembled brake 550 back and forth. The approximately tubular brake housing part 166 is made of an elastic material, preferably elastic rubber or silicone. The approximately cylindrical disc-shaped brake 550 is arranged around the shaft between the bearing shield 42 and the fan wheel 36. A brake seal 901 is approximately identical in shape to an end face of an outer circumference of the brake shield 702 and is clamped between the end face of the brake shield 702 and the bearing shield 42. The disc-shaped brake shield 702, which is provided with radial, star-shaped reinforcements, has a smaller outer diameter than the bearing shield 42. Trapezoidal protrusions with axial through-holes are formed on the circumferential region of the brake shield 702 that faces the bearing shield 42; the brake mounting screws 900 are guided through these protrusions. The lining carrier has internal teeth which engage axially in the teeth of the toothed ring of the driver 70. The lining carrier is arranged between the brake shield and the magnet body 154 and lies in a lining area that is bounded by the brake shield 702, the magnet body 154 and the approximately tubular brake housing part 166. A coil 155 is arranged in the magnet body 154. A brake control line for controlling the coil 155 is equipped with a brake connector 698, which can be inserted into a complementary socket in the magnet body. This simplifies the replacement of the brake 550, as no new lines need to be routed through the motor to the terminal box 110. The brake control line is guided through the eyelet in the bearing plate 42 to the terminal box and strain-relieved by means of the screw connection in the eyelet. A ring-shaped opening between the shaft 66 and the magnet body 154 is sealed by a brake seal 95. A release lever 53 for releasing the brake 550 is supported on the magnet body by a cylindrical pin 59 and is located on the end face of the magnet body 154 facing away from the brake shield. In axial plan view, the release lever has the shape of a stud, the opening of which engages the shaft 66. Two through-holes are symmetrically arranged in the legs of the stud. A release pin screw 56 is guided through one of these through-holes and then through an opening in the magnet body. One end of the release pin screw 56 is screwed to an armature disk 149 of the brake 550, which is located between the magnet body 154 and the brake pad carrier 168. The release lever is held on the magnet body at the other end of the release pin screw 56 by means of a conical spring and an adjusting nut 58. The air thread pin 64 is screwed into the air lever 53 corresponding to a pin of the riding spur.A hand lever 51 for manually releasing the brake can be screwed onto this threaded release pin 64. When not in use, the hand lever 51 can be clamped to the cooling fins 54 using the clamps 46. The fan wheel 36 is positioned between the fan lever 53 and the grille structure of the fan cover 35 in the assembled state and is enclosed by the fan cover 35. The fan cover 35 has the shape of a rectangular shell with rounded corners and a flat base, the base of which is not closed but formed by a grid structure. The fan cover 35 is slid onto the bearing plate 42 with its opening facing the bearing plate 42, so that the grid structure of the fan cover runs approximately parallel to the bearing plate 42. With the hand lever 51 removed, the elongated hole in the second subsection of the fan cover can be closed by a closing element 55. The second section of the fan hood 35 has approximately wave-shaped elevations and depressions in the sections which, in the assembled state, are designed as a continuation of the flat bearing surfaces of the stator housing 52. A saucer-shaped protective cover 705 is arranged to cover the grid structure of the fan housing 35. A spacer 706 is arranged between the protective cover 705 and the fan housing 35, ensuring that sufficient air can flow through the grid structure to the fan wheel 36. The protective cover 705 and the base of the fan housing 35 have through-holes through which a protective cover screw 707 and a protective cover hexagon screw 715, respectively, are inserted. The protective cover screw 707 and the protective cover hexagon screw 715 are screwed into internal threads in blind holes on the end faces of the spacer 706. Thus, the protective cover 705 and the spacer 706 are fastened to the fan housing 35. A further key 4 at a fan-side end area of ​​the shaft 66 serves for a rotationally fixed, positive-locking connection of additional devices to the shaft 66. Fig. 3 shows the electric motor 50 according to the invention shown in Fig. 1 in a schematic longitudinal section. The flange shield 64 and the bearing shield 42, together with the stator housing 52, enclose a cylindrical interior space within the housing of the electric motor 50. The shaft 66 is supported relative to the housing by the fixed bearing 11 and the floating bearing 44. The fixed bearing 11 is arranged in a fixed bearing holder formed in the flange shield 64 and is held on the shaft side by the shaft diameter step and the retaining ring 10 with the support washer 104. The retaining ring 10 snaps into an annular groove in the shaft 66. On the housing side, the fixed bearing 11 is held by an annularly circumferential corner of the fixed bearing holder and by the retaining ring for a bore 12. The retaining ring for a bore 12 engages in a groove in the fixed bearing holder in the flange shield 64. The remaining opening of the shaft passage in the flange shield 64 is sealed by the shaft seal 106. The stator 16, comprising the stator winding 20 with winding head 21 and the stator lamination stack 18, is fixed in the stator housing 52 by means of fasteners 80, in particular by being pressed into the stator housing 52. The rotor stack 72, pressed onto the shaft 66, has a rotor lamination stack 74. The laminations of the rotor lamination stack 74 are connected to one another, for example by stamping and / or by a rotor casting 76, which forms a squirrel cage for the rotor 1. The rotor casting 76, forming an annular ridge, projects axially from both sides of the rotor lamination stack 74 in the direction of the shaft 66. The floating bearing 44 is arranged in the cylindrical bearing receptacle. The inner ring of the floating bearing 44, with its stator housing-side end face abutting a radial surface of a further shaft diameter step, provides shaft-side support to the rotor assembly 72. The spring element 41 is arranged between the floating bearing 44 and the bearing shield 42 in the cylindrical bearing receptacle and rests on a support surface in the bearing shield. The outer ring diameter of the spring element 41 is larger than the diameter of the shaft passage and less than or equal to the diameter of the cylindrical bearing receptacle. The inner opening diameter of the annular spring element 41 is at least as large as the shaft diameter of the shaft 66 in the region of the cylindrical bearing receptacle. On the bearing shield side, the spring element 41 contacts the bearing shield 42 at least at one support surface. This support surface only needs to absorb the spring force of the spring element in the axial direction.When the shaft 66 undergoes an axial change in length between the fixed bearing 11 and the floating bearing 44, the floating bearing 44 follows the movement of the shaft diameter step and the inner ring of the floating bearing 44 remains pressed against a radial surface of the shaft diameter step due to the spring force of the spring element 41. The inner ring of the floating bearing 44 is axially fixed by the further shaft diameter step and the driver 70. Therefore, the spring element 41 can also be omitted. The driver 70, in turn, is axially fixed by the retaining ring 62 for the driver, which is engaged in a circumferential annular groove of the shaft 66. The bearing shield-side ring of the driver 70 lies within the shaft passage of the bearing shield 42 and almost completely closes the annular opening between the shaft 66 and the bearing shield 42. The brake shield 702 is attached to the bearing shield 42. The circumferential area shaped towards the bearing shield 42 includes an annular protrusion on the outer end face of the bearing shield 42, which lies outside the housing. This ensures that the brake shield 702 is approximately centered around the shaft 66. This facilitates the assembly of the brake shield 702 and thus of the pre-assembled brake 550. A disc-like portion of the outer end face of the brake shield 702 serves as a friction surface for an annular brake pad 169 of the pad carrier 168. The brake pad carrier 168 comprises two metal discs, preferably made of aluminum, which are connected to each other and separated by a damping material. The damping material reduces the noise generated when the brake 550 is applied. The annular brake pad 169 is arranged concentrically around the shaft 66 on the metal disc facing the brake shield 702. Another brake pad is arranged on the opposite metal disc facing the magnet body 154. The internal teeth of the brake pad carrier 168 engage with the toothed ring of the driver 70. Blind holes, open towards the brake pad carrier and arranged axially, are provided in the magnet body 154.In these blind holes in the magnet body 154, helical compression springs are inserted which, when the brake 550 is applied, press the armature disc 149 against the pad carrier 168 or the further brake pad, whereby, due to the axial mobility of the pad carrier 168, the brake pad 169 presses against the disc-like part of the end face of the brake shield 702. In a further embodiment, the pad carrier 168 and the brake pad 169 are formed in one piece. The pad carrier 168 and the brake pad 169 are then made of the same material, preferably a homogeneous or heterogeneous, in particular abrasion-resistant composite material such as, for example, fiber-reinforced rigid plastic. A coil 155 is arranged in the magnet body 154. When current flows through the coil 155, it magnetizes the magnet body 154, thereby attracting the armature disk 149 against the force of the helical compression springs. When current flows through the coil 155, the brake 550 is released, and the shaft 66 can be driven without braking, i.e., it is movable. To dampen the noise generated when the armature disk 149 strikes the magnet body 154, a disc-shaped damping plate 718 is arranged between the magnet body 154 and the armature disk 149. The lining area between the brake shield 702 and the magnet body 154 is radially sealed by the approximately tubular brake housing part 166. The elastic material of the tubular brake housing part 166 has a lower thermal conductivity than, for example, steel. When the brake 550 is released, heat is generated in the magnet body 154 due to the current-carrying coil 155 and the magnetic field. This heat is not transferred via the brake housing part 166 to the brake shield and thus to the housing of the electric motor 50. The electric motor 50 is not subjected to the additional heat load and can be operated more efficiently. The approximately tubular brake housing part 166 is elastic enough to be slipped over the magnet body 154 and against the brake shield 702. This simplifies the assembly of the brake 550.In the assembled state, the tubular brake housing part 166 rests with one end region on a protrusion of the pad carrier-side end face of the brake shield 702 and with the opposite end region on a partial area of ​​a circumferential surface of the magnet body 154. Additionally, the tubular brake housing part 166 prevents abrasion from the pad carrier 168 or the brake pad 169 from being distributed uncontrollably or even being caught by the airflow generated by the rotating motor fan 36 and transported towards the housing of the electric motor 50. There, the abrasion would deposit on the cooling fins and prevent efficient cooling of the electric motor 50. Towards the bottom of the fan shroud 35, the remaining opening between the magnet body 154 and the shaft 66 is sealed by the brake seal 95. Following the brake seal in the axial direction away from the housing is the air lever 53, which rests on the end face of the magnet body facing away from the housing, as the air lever 53 is fastened to the armature disc by means of the air pin screw 56 and the adjusting nut 58. Between the base of the fan housing 35 and the fan lever 53, the fan wheel 36 is fixedly attached to the shaft 66 in a rotationally fixed manner, spaced apart from the fan lever 53. The fan wheel 36 has a radially projecting fan disc forming a truncated cone shell, the base of which is open towards the bearing shield 42. A radially extending fan blade 38 projects axially towards the base of the fan housing 35 on the side of the fan disc facing away from the housing, approximately perpendicular to the fan disc. The fan disc transitions radially towards the shaft 66 into a U-shaped mounting area 37 of the fan wheel 36. An innermost edge of the mounting area 37 forms the inner surface of a fan wheel cylinder that is in contact with the shaft 66. The shaft-side leg of the U of the mounting area is clamped by the further shaft diameter step of the shaft 66 and the further retaining ring 32. Thus, the fan wheel 36 is fixed in the axial direction. The fan wheel 36 is preferably made of a lightweight material such as plastic or aluminum, molded in one piece. If a higher moment of inertia is required, a heavier fan wheel made of die-cast metal or steel is preferable. The fan cover 35 is fitted over the fan wheel 36 and the bearing shield 42 and has a passage for the shaft 66. This allows a driven device to be mounted axially behind the fan cover, viewed from the housing. Blind holes in the end faces of the shaft 66, a key 3 and a snap ring 2 serve as further centering and / or fastening options for various driven elements. Reference symbol list 1 Rotor 2 Snap ring 3 Key 4 Additional key 7 Flange 8 Flange bore 9 Sealing screw 10 Retaining ring 11 Fixed bearing 12 Retaining ring for bore 14 Washer 15 Hex bolt 16 Stator 17 Hex nut 18 Stator lamination stack 19 Socket head cap screw 20 Stator winding 21 Winding head 22 Additional hex bolt 24 Eye bolt 31 Fan key 30 Shaft seal 32 Additional retaining ring 35 Fan cover 36 Fan wheel 38 Fan blades 41 Spring element 42 Bearing shield 44 Floating bearing 46 Clip 47 Fan O-ring 49 Trapezoidal bead 50 Electric motor 51 Hand lever 52 Stator housing 53 Fan lever 54 Cooling fins 55 Sealing piece 56 Fan pin screw 57 Conical spring 58 Fan hex nut 59 Fan cylinder pin 60 Mounting holes 62 Retaining ring 64 Flange plate 66 Shaft 67 Terminal box base 70 Drive pin 71 Drive pin key 72 Rotor assembly 74 Rotor lamination assembly 76 Rotor casting 80 Fastener 90 Foot 91 Foot hex nut 93 Foot washer 94 Foot socket head cap screw 95Brake seal 96 Reduction 100 Flange hexagon nut 103 Stud bolt 104 Support washer 106 Shaft seal 107 Splash washer 108 Type plate 109 Grooved nail 110 Terminal box 111 Gasket for the terminal box base 112 Terminal box base 113 Additional screw 115 Terminal plate 116 Clamping washer 117 Clamping threaded rod 118 Spring washer 119 Mounting screw 123 Terminal box hexagon screw 128 Fan washer 129 Sealing screw with O-ring 131 Gasket for the terminal box cover 132 Terminal box cover 134 Sealing screw with O-ring 136 Brake connection part 137 Brake connection part screw 139 Outer screw 140 Outer washer 149 Anchor washer 153 Terminal strip 154 ​​Magnet body 155 Coil 156 Warning label 161 Brake mounting screw 164 Ventilation thread pin 166 Brake housing part 168 Pad carrier 169 Brake pad 217 Brake relay 219 Clamping nut 262 Connecting terminal 390 O-ring 418 Screw connection 550 Brake 615 Additional connecting terminal 616 Mounting plate 632Mounting plate screw 698 Brake plug 705 Protective cover 706 Spacer 707 Protective cover screw 715 Protective cover hexagon screws 718 Damping plate 900 Brake mounting screw 901 Brake sealing ring

Claims

Electric motor (50) with an electromagnetically actuated brake, wherein the electric motor (50) comprises a housing, a rotor (1) and a stator (16), wherein the rotor (1) comprises a shaft, a rotor lamination stack and a rotor casting designed as a rotor cage, wherein the shaft (66) is supported in the housing by a fixed bearing (11) and a floating bearing (44), wherein the floating bearing (44) is arranged to be axially movable and the shaft (66) has shaft sections with different diameters, whereby the transitions of the shaft sections form shaft diameter steps, wherein a spring element is arranged axially between the floating bearing (44) and a housing part, namely a bearing shield (42), wherein at least one ring of the floating bearing (44) is pressed against a shaft diameter step by the spring element, wherein the spring element is designed as a disc spring.wherein the brake (550) comprises a magnetic body and a coil mounted in the magnetic body, and a brake control line is provided for controlling the coil, and the brake control line is detachably connected to a coil connection in the magnetic body by means of a brake connector, wherein the brake connector and the coil connection are designed as electrical plug connections, wherein the brake connector has a connector part and the coil connection has a corresponding mating connector part, wherein the connector part is electrically connected by means of the brake control line to a connection option in the terminal box (110) in order to electrically connect the brake control line to an external control electronics or to control electronics located in the terminal box (110), and the mating connector part is electrically connected to the coil.wherein the brake connection line is guided through an eyelet of a bearing shield (42) of the electric motor (50), wherein the brake connection line is strain-relieved by means of a screw connection in the eyelet, wherein the brake (550) comprises a brake pad (169) arranged in a lining area and a tubular brake housing part, wherein the tubular brake housing part has a smaller inner diameter than an outer diameter of the magnet body and the tubular brake housing part is made of an elastic material such that it can be slipped over the magnet body and the tubular brake housing part surrounds the lining area in a housing-forming manner, wherein the tubular brake housing part is made of an elastic material, namely rubber or silicone, which conducts heat less effectively than metal or stainless steel, wherein the brake (550) has a brake pad (169) connected to a shaft (66) of the electric motor (50) in a rotationally fixed manner.The brake pad carrier (168) comprising the brake pad (169) and an armature disk (149) which is fixed against rotation relative to a housing of the electric motor (50), wherein the armature disk (149) and the brake pad carrier (168) are arranged to be axially movable in the pad area, wherein the brake pad carrier (168) comprises two metal disks, namely made of aluminum, which are connected to each other by a damping material and the brake pad (169) is arranged on the metal disks. Electromagnetically actuated brake (550) with an electric motor (50) according to claim 1, wherein the brake (550) comprises a magnetic body and a coil mounted in the magnetic body and a brake control line for actuating the coil is provided, characterized in that the brake control line is detachably connected to a coil connection in the magnetic body by means of a brake connector, wherein the brake connector and the coil connection are designed as electrical plug connections, wherein the brake connector has a connector part and the coil connection has a corresponding mating connector part, wherein the connector part is electrically connected by means of the brake control line to a connection point in a terminal box (110) of the electric motor (50).to electrically connect the brake control line to an external control electronics unit or one located in the terminal box (110), and the mating connector part is electrically connected to the coil. Brake (550) according to claim 2, characterized in that the brake connection line is led from the connection box (110) through a housing of the electric motor (50) to the magnet body. Brake (550) according to claim 2 or 3, characterized in that the brake connection line is guided through an eyelet of a bearing shield (42) of the electric motor (50). Brake (550) according to claim 4, characterized in that the brake connection line is strain relieved by means of a screw connection in the eyelet. Brake (550) according to one of claims 2 to 5, characterized in that the brake (550) comprises a brake pad (169) arranged in a lining area and a tubular brake housing part, wherein the tubular brake housing part has a smaller inner diameter than an outer diameter of the magnet body and the tubular brake housing part is made of an elastic material such that it can be slipped over the magnet body and the tubular brake housing part surrounds the lining area in a housing-forming manner. Brake (550) according to one of claims 2 to 6, characterized in that the tubular brake housing part is made of an elastic material which conducts heat less well than metal or stainless steel, in particular rubber or silicone. Brake (550) according to one of claims 2 to 7, characterized in that the brake (550) comprises a pad carrier (168) having the brake pad (169) and connected non-rotatably to a shaft (66) of the electric motor (50), and an armature disk (149) which is non-rotatably connected to a housing of the electric motor (50), wherein the armature disk (149) and the pad carrier (168) are arranged to be axially movable in the pad area. Brake (550) according to claim 8, characterized in that the pad carrier (168) comprises two metal discs which are connected to each other by a damping material and the brake pad (169) is arranged on the metal discs. Brake (550) according to claim 9, characterized in that the pad carrier (168) and the brake pad (169) are made in one piece and consist of a single material. Brake (550) according to one of claims 2 to 9, characterized in that the brake (550) is pre-assembled.

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