Electric motor with encoder

Abstract

An electric motor comprising a rotor (1) having a shaft, a housing, and an encoder (219), wherein the shaft is supported in the housing by means of a fixed bearing (11) 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 between the floating bearing and a housing part, wherein at least one ring of the floating bearing is pressed against a shaft diameter step by the spring element, wherein the housing comprises a stator housing surrounding a stator which has cooling fins projecting radially from the stator housing parallel to each other, wherein the encoder (219) comprises an encoder shaft non-rotatably connected to a shaft of the electric motor and an encoder housing (220) non-rotatably connected to a housing of the electric motor.wherein the encoder housing (220) is at least partially surrounded by a housing-forming part, wherein the encoder housing (220) is attached to a fan hood (35) of the electric motor which surrounds a fan wheel (36) in a housing-forming manner, wherein when the fan wheel (36) is running, an airflow in the axial direction flows unhindered past or through the housing-forming part, wherein the housing-forming part is attached to the fan hood (35), wherein the encoder shaft is designed as a spreading shaft (221) and is positively connected to the shaft, wherein the housing-forming part is designed as a stamped sheet metal part (657), wherein the stamped sheet metal part (657) has a hexagonal base surface, a square wing is bent at approximately a right angle at every second edge of the hexagonal base surface, and an end region of the wing is bent at a right angle so that they project outwards approximately parallel to the base surface,wherein the end regions of the wings have through holes through which cage screws (659) are passed and the cage screws (659) are screwed into cage nuts which are attached to the fan shroud (35).

Description

[0001] The invention relates to an electric motor with encoder.

[0002] An electric motor with encoder is known from DE 10 2005 009 601.

[0003] The invention is therefore based on the objective of further developing an electric motor with encoder, wherein the electric motor with encoder is easy and safe to manufacture and is more environmentally friendly to operate.

[0004] According to the invention, the problem is solved in the electric motor with encoder according to the features specified in claim 1 or 2.

[0005] Important features of the invention in the electric motor are that the electric motor comprises a rotor having a shaft, a housing and an encoder, wherein the shaft is supported in the housing by means of 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 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 housing comprises a stator housing surrounding a stator which has cooling fins projecting parallel to each other approximately radially from the stator housing, wherein the encoder comprises an encoder shaft which is non-rotatably connected to a shaft of the electric motor and aThe sensor housing is rotationally fixed to the housing of the electric motor, wherein the sensor housing is at least partially enclosed by a housing-forming part, and wherein the sensor housing is attached to a fan housing of the electric motor, which in turn surrounds a fan wheel. When the fan wheel is running, an airflow in the axial direction flows unimpeded past or through the housing-forming part, and wherein the housing-forming part is attached to the fan housing. The sensor shaft is designed as a spreading shaft and is positively connected to the shaft. An advantage of this design is that the sensor is protected from external influences, such as passing or flying objects. The sensor can still be mounted safely and easily on the electric motor without many additional or modified parts. The housing-forming part positively influences the natural vibrations of the fan housing and thus reduces noise generation.

[0006] Important features of the invention in the electric motor are that the encoder has an encoder shaft that is rotationally fixed to a shaft of the electric motor and an encoder housing that is rotationally fixed to a housing of the electric motor, wherein the encoder housing is at least partially surrounded by a housing-forming part. It is advantageous that the encoder is protected from external influences, such as passing or flying objects. The encoder can nevertheless be mounted safely and easily on the electric motor.

[0007] In an advantageous embodiment, the sensor housing is attached to a fan housing of the electric motor, which surrounds a fan wheel. When the fan wheel is running, an airflow in the axial direction flows unimpeded past or through the housing-forming part. An advantage of this is that few noise-generating air turbulences are created, and the electric motor is ventilated as if it were without a sensor. The sensor dampens the natural vibrations of the fan housing and thus reduces noise generation at the fan housing.

[0008] In a further advantageous embodiment, the housing-forming part is attached to the fan shroud. An advantage of this is that the housing-forming part dampens the natural vibrations of the fan shroud and thus reduces noise generation.

[0009] In a further advantageous embodiment, the encoder shaft is designed as a spreading shaft and is positively connected to the shaft. The advantage here is that the encoder shaft is attached to the shaft of the electric motor simply and securely.

[0010] In a further advantageous embodiment, the sensor housing is located outside the fan shroud. An advantage of this is that the sensor can be retrofitted and is easily attached to the fan shroud.

[0011] In a further advantageous embodiment, the encoder housing is supported on the bearing shield by a support element. An advantage of this is that the encoder can be mounted securely and easily on the electric motor. The encoder can also be mounted on an electric motor without a fan shroud.

[0012] In a further advantageous embodiment, the housing-forming part is designed as a sensor cover, which has a cylindrical outer surface. An advantage of this is that the housing of the electric motor is a continuous unit and differently shaped sensors can be enclosed by the sensor cover. The sensor cover is easy to mount and dampens the natural vibrations of the fan housing.

[0013] In a further advantageous design The axial cross-section of the sensor housing exhibits n-fold discrete rotational symmetry, where n is an integer greater than two, in particular n equals four. An advantage of this is that fewer natural vibrations of the sensor housing can be excited by the fan wheel. Thus, the noise generation is dampened.

[0014] In a further advantageous embodiment, the sensor housing has the shape of a bowl with a square circumferential surface, the four corners of which are rounded, with a base of the sensor housing having recesses. An advantage of this is that the sensor housing can be manufactured practically identically to the fan housing. The rounded corners act as a stiffener for the sensor housing. An airflow generated by the fan wheel flows to the fan wheel and past the electric motor with minimal disturbance. The fan wheel and the airflow excite only a few natural vibrations of the sensor housing. Thus, the noise generation is dampened.

[0015] In a further advantageous embodiment, the sensor cover is clamped onto the fan cover. An advantage of this is that the sensor cover is securely mounted to the fan cover. This prevents rattling noises.

[0016] In a further advantageous embodiment, the housing-forming part is designed as a stamped sheet metal part. An advantage of this is that the housing-forming part is easy to manufacture and assemble.

[0017] In a further advantageous embodiment, the stamped sheet metal part has a hexagonal base surface, with a square wing bent at approximately a right angle at every second edge of the hexagonal base surface, and an end region of the wing is bent at a right angle so that the end region projects outwards approximately parallel to the base surface. An advantage of this is that the sheet metal part is less susceptible to excitation of its natural vibrations.

[0018] In a further advantageous embodiment, the stamped sheet metal part is attached to the fan housing. An advantage of this is that the natural vibrations of the fan housing are dampened.

[0019] In a further advantageous embodiment, the end regions of the blades have through holes through which cage screws are passed and which are screwed into cage nuts that are attached to the fan housing. An advantage of this is that the stamped sheet metal part is easily and securely mounted to the fan housing and effectively dampens the natural vibrations of the fan housing.

[0020] Further advantages will become apparent from the dependent claims. The invention is not limited to the combination of features of the claims. For the person 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. 1 rotor 2 snap ring 3 Keyway 4 other key 7 flange 8 Flange bore 9 Locking screw 10 retaining ring 11 Fixed camp 12 retaining ring for bore 14 washer 15 Hex bolt 16 stator 17 Hex nut 18 Stator lamination package 19 cylinder screw 20 Stator winding 21 winding head 22 another hexagon screw 24 Eye screw 31 Fan key 30 shaft seal 32 additional retaining ring 35 fan hood 36 fan wheel 38 fan blades 41 spring element 42 Warehouse sign 44 Loose bearing 49 isosceles, right-angle-forming thickening 50 electric motor 52 Stator housing 54 Cooling fins 55 trapezoidal bulge 60 Mounting holes 64 Flange plate 66 Wave 67 Junction box double 72 Rotor package 74 Rotor lamination package 76 Rotor casting 80 Fasteners 104 support disc 106 shaft seal 107 splash disc 108 Type plate 109 notched nail 110 Junction box 111 Seal for the junction box base 112 Terminal box base 113 another screw 115 Terminal block 116 Clamping disc 117 Clamping threaded rod 118 spring washer 119 fastening screw 123 Junction box hexagon screw 128 Fan disc 129 Sealing screw with O-ring 131 Seal for the junction box cover 132 Junction box cover 134 Sealing screw with O-ring 219 Transmitter 220 Transmitter housing 221 Spreading wave 224 crescent-shaped stamped part 225 Support sleeve 226 Support screw 232 Sensor screw 233 Mother 262 Connection terminal 269 spout 319 Clamping nut 361 Transmitter cover 390 O-ring 616 Mounting plate 619 Connection cover 651 Cage mother 657 Sheet metal stamping part 659 cage screw 950 sealing plug

[0021] The invention will now be explained in more detail with reference to illustrations: 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 in a surface that is either flat or has a lesser curvature than the stator housing 52. In particular, the free ends lie in four substantially flat surfaces arranged approximately at right angles to each other. Trapezoidal ridges 55 at the end faces of the outer surfaces of the stator housing 52 form corner elements between the flat surfaces. The outer surfaces of the outermost cooling fins 54 of each surface are connected to each other via a thickening 49 in the stator housing 52 that forms an isosceles right angle. The thickening 49 appears L-shaped from an axial view.In at least one of the flat surfaces, a blind-hole-like mounting bore 60 with an internal thread is provided in a thickening 58 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 can be attached to the stator housing 52 as a stand.

[0022] A cuboid-shaped terminal box 110 is screwed onto a terminal box base 67 provided for this purpose. The 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.

[0023] A nameplate 108 is attached to the flat surface 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.

[0024] A housing of the electric motor 50 comprises a flange shield 64, a bearing shield 42 and the stator housing 52. The end faces of the stator housing 52 are closed off by the bearing shield 42 and the flange shield 64 – except for a passage for a shaft 66 in the flange shield 64 and a shaft passage in the bearing shield 42.

[0025] A flange 7 for attaching driven devices is integrally formed on the flange shield 64. For this purpose, the flange 7 has a flange bore 8. A brace between the flange shield and a base body of the flange increases the stability of the flange shield while simultaneously reducing the amount of material required. The base body of the flange shield 64 has a trapezoidal bead forming a corner on its circumferential surface. A hexagonal screw 15, with a washer underneath, is screwed into an internal thread of a bore in the trapezoidal bead on the flange shield 64. The screw passes through a through-hole in a trapezoidal bead 55 on the flange shield side of the stator housing 52. An interior of the housing in the passage for the shaft 66 in the flange shield 64 is protected from contaminants such as dust, water, and / or gear oil by a splash guard 107 and a shaft seal 106.A driven device can be flanged to flange 7 using stud bolts and flange hexagon nuts. A rotating part of this driven device can be fixed in a rotationally fixed manner, in particular by means of the key 3, positively locking it to shaft 66. Blind holes are provided in the end faces of the shaft. 66 and a snap ring 2 serve as a further centering and / or fastening option for various elements to be driven.

[0026] A thickening is formed on the outer edge of the bearing shield 42, which has a through bore aligned parallel to the shaft 66 and a blind hole with an internal thread arranged perpendicular to it and extending radially to the shaft 66. The blind hole with an internal thread extending radially to the shaft 66 serves to fasten the additional hexagon screws 22. A socket head cap screw 19 is guided through the bores in the bearing shield 42, which are aligned parallel to the shaft 66, and bores in the trapezoidal ridges 55 on the stator housing 52, and is screwed into a hexagon nut 17, so that the bearing shield 42 is fastened to the stator housing 52.

[0027] A fan hood 35 is attached to the circumference of the bearing shield 42, or partially overlapped with the bearing shield 42 in an inaxial direction and fastened to the bearing shield 42 with further hexagon screws 22.

[0028] The fan housing 35 has the shape of a rectangular shell with rounded corners and a flat base, the base being open but formed by a grid structure. The fan housing 35 is slid onto the bearing shield 42 with its opening facing the bearing shield 42, so that the grid structure of the fan housing runs approximately parallel to the bearing shield 42. A circumferential wall of the fan housing 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 corresponding circumference on the stator housing side, suitable for partially overlapping and fitting onto the bearing shield 42, which tapers towards the base of the fan housing 35 by a step.

[0029] The second section of the fan hood 35 has approximately wave-shaped elevations and depressions in the sections which, in the assembled state, are formed as a continuation of the flat surfaces of the stator housing 52, which are covered in Fig. 1 by a sensor hood 361.

[0030] The sensor housing 361 for a sensor 219 is clamped onto the fan housing 35. The sensor housing 361 is shaped analogously to the fan housing. Sheet metal screws 34 serve to fix the sensor housing 361 to the fan housing 35. Due to the clamping, the sensor housing 361 is held securely even without the sheet metal screws 34, and vibrations of the sensor housing are dampened. Rattling of the sensor housing 361 against the fan housing 35 is prevented. At the end area facing away from the housing, the raised areas and recesses are visible as described for the fan housing.

[0031] Encoders as angle measuring systems are generally known.

[0032] Fig. 2 shows the electric motor 50 according to the invention shown in Fig. 1 in a schematic longitudinal section.

[0033] A stat 16 has a stator lamination stack 18 and a stator winding 20 with a winding head 21 and is mounted in the stator housing 52. The stat 16 with the stator windings 20 with winding head 21 and the stator lamination stack 18 is fixed in the stator housing 52 by means of fastening means 80, in particular by being pressed into the stator housing 52.

[0034] 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 manner approximately centrally on the shaft 66 in the shaft section with the largest shaft diameter, in particular by being pressed onto this shaft section.

[0035] The rotor assembly 72 comprises 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 bead, projects axially from the shaft 66 on both sides of the rotor lamination stack 74.

[0036] The flange shield 64 and the bearing shield 42, together with the stator housing 52, enclose the cylindrical interior of the housing of the electric motor 50. The shaft 66 is supported relative to the housing by a fixed bearing 11 and a floating bearing 44.

[0037] The fixed bearing 11, designed as a deep groove ball bearing, is pushed onto the shaft 66 on the flange shield side, and 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. The retaining ring 10 is snapped into an annular groove in the shaft 66. The fixed bearing 11 is arranged on the stator housing side in a fixed bearing holder formed in the flange shield 64 and is secured by an annularly circumferential corner of the fixed bearing holder and by a retaining ring for a bore 12. The retaining ring 12 for a bore is engaged in a groove in the fixed bearing holder in the flange shield 64.

[0038] On the end shield side, a floating bearing 44 designed as a deep groove ball bearing is pushed onto the shaft 66 up to a further shaft diameter step. By having its inner ring of the floating bearing 44 abut a radial surface of a further shaft diameter step with its stator housing-side end face, the floating bearing 44 is supported on the shaft side towards the rotor assembly 72.

[0039] The bearing shield 42 forms a thickening in the area of ​​the shaft passage. The thickening is formed towards the stator housing 52. A hollow cylinder in the thickening of the bearing shield 42, which is completely open towards the stator housing, is formed concentrically with the shaft passage and has a larger diameter than the shaft passage, forming a cylindrical bearing receptacle for the floating bearing 44.

[0040] A compensating washer is designed as an annular spring element 41, preferably as a disc spring. The spring element 41 is arranged between the floating bearing 44 and the bearing shield 42 in the cylindrical bearing receptacle and is supported on a bearing surface in the bearing shield. The bearing surface only needs to absorb the spring force of the spring element 41 in the axial direction. 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 spring element 41 is at least as large as the shaft diameter of the shaft 66 in the region of the cylindrical bearing receptacle. The floating bearing 44 is movably fixed in the axial direction between the further shaft diameter step and the spring element 41 in the cylindrical bearing receptacle in the bearing shield 42.Movable in the sense that the floating bearing 44 can follow axial displacements of the subsequent shaft diameter step due to a change in the length of the shaft 66. When the shaft 66 undergoes an axial change in length, the floating bearing 44 follows the movement of the shaft diameter step, and the inner ring of the floating bearing 44 remains in place due to the spring force of the spring element 41. The spring element 41 is pressed against the radial surface of the shaft diameter step. It springs accordingly without deforming the floating bearing 44 or adversely affecting the 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 accommodated.

[0041] In an alternative embodiment, the spring element presses against the inner ring of the floating bearing 44. In this case, the fixed bearing and the floating bearing are fixed in the electric motor without preload. In a further alternative embodiment, the spring element presses against the inner ring and the outer ring.

[0042] The shape and material of the spring element 41 are selected such that, during many length change cycles of the shaft 66, i.e., expansion and contraction in the axial direction, over the service life of the electric motor 50, the floating bearing 44 is axially fixed by the spring element 41. The contact force of the spring element 41, taking into account manufacturing tolerances, is less than the maximum axial force that the floating bearing 44 can withstand. In particular, the contact force is adjustable by the number and / or shape of the spring element 41, which is preferably designed as a disc spring. Thus, the spring element 41 also acts as a compensating washer. Suitable materials for the spring element 41 include metal, in particular spring steel, which is also suitable for heat transfer between the bearing and the housing.

[0043] 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 44 can be dimensioned as a smaller bearing and the electric motor 50 is more compact.

[0044] A thickened outer edge of the bearing shield 42 is also shaped towards the stator housing 52 and has further cooling fins on its outer edge, which are at least partially designed as a continuation of the cooling fins 54 of the stator housing 52.

[0045] 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 forms a frame towards the terminal box base 67, which corresponds approximately to an end face of the terminal box base 67. Fastening screws 119 are screwed into the reinforcements through through holes in the frame.A seal 111 for the junction box base 112 is clamped between the frame of the junction box base 112 and the end face of the junction box base 67. Cable glands of various sizes are located in one wall of the junction box base 112, which can be closed using appropriately sized sealing screws with O-rings.

[0046] The terminal box lower part 112 projects in an axial direction beyond the bearing shield side in a terminal box area. The terminal box base 67 and the bearing plate 42 extend outwards, forming a base plate in this terminal box area. Various clamping devices are located on this base plate, projecting into the interior of the terminal box 110, in particular a connecting clamp 262 mounted on a mounting plate 616. The mounting plate 616 is fastened to the base plate by means of a fastening screw. Furthermore, a cuboid-shaped projection extends from the base plate into the interior of the terminal box 110. A clamping threaded rod 117 is screwed into this projection. A clamping nut 319 is screwed onto the clamping threaded rod 117, which presses a spring washer 118 and a clamping washer 116 onto the projection.

[0047] The terminal plate 115 and the various clamping devices can be 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. The terminal box 110 is fitted with a terminal box cover 132 and a connection between the The terminal box cover 132 and the terminal box base 112 are sealed by the seal 131 clamped in place for the terminal box cover 132. For this purpose, the terminal box cover 132 is screwed to the terminal box base 112 using the terminal box hexagon screws 123.

[0048] In a bearing shield end section of the shaft 66, a fan wheel 36 is rotationally fixed to the shaft 66, in particular by positive locking, for example with a flat in the shaft cross-section or a fan wheel key 31. In the axial direction, the fan wheel 36 is positively and / or force-fitted by an additional shaft diameter step and a further retaining ring 32. The fan wheel 36 is arranged in the assembled state between the bearing shield 42 and the grid structure of the fan housing 35 and is enclosed by the fan housing 35.

[0049] The fan wheel 36 has a radially projecting fan disc forming a truncated cone shell that is open with its base towards the bearing shield 42. A radially extending fan blade 38 projects axially towards the bottom 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 shell 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 secured in the axial direction.

[0050] The fan wheel 36 is preferably molded in one piece from a lightweight material such as plastic or aluminum. If a higher moment of inertia is required, a heavier fan wheel made of die-cast metal or steel is preferable.

[0051] The fan cover 35 is placed over the fan wheel 36 and the bearing shield 42 and has an opening in axial extension of the shaft 66. This allows a driven device or a sensor 219 (as an angle gauge) to be mounted axially behind the fan cover, even when viewed from the housing.

[0052] A spreading shaft 221 of the encoder 219 is inserted into a recess of the shaft 66 and is positively connected to the shaft 66 by spreading. A crescent-shaped stamped part 224 surrounds an encoder housing 220 with a semicircular section and is attached to it. A gripping section of the crescent-shaped stamped part 224 projects radially from the encoder housing. A support screw 226 is guided through a hole in the gripping section of the crescent-shaped stamped part and through a support sleeve 225 and screwed into the bearing shield 42. Thus, the encoder housing 220 is supported on the bearing shield via the crescent-shaped stamped part 224 and the support screw 226 or the support sleeve 225. This support also works for fanless electric motors without a fan shroud 35.

[0053] In a further embodiment, the sensor housing 220 is only attached to the fan cover 35. In this embodiment, a section of a sensor housing part engages behind the fan cover 35 – viewed from the sensor housing 220. A sensor screw 232 is guided through a recess in the fan cover 35 and a hole in the section of the sensor housing part and interacts with a nut in such a way that the sensor housing is attached to the fan cover.

[0054] A housing-forming part is designed as a sensor cover 361 and surrounds the sensor housing 220 in a housing-forming manner. The sensor cover 361 has a shape analogous to the fan cover 35, in particular a cylindrical outer surface with an approximately square cross-section with rounded corners and a grid structure as a base. An airflow generated by the rotating fan wheel 36 flows in an axial direction through the grid structure of the sensor cover 361 past the sensor housing 220, through the grid structure of the fan cover 35 to the fan 36, and further along the stator housing 52.

[0055] A terminal cover 619 is axially mounted onto the sensor housing or otherwise connected to the sensor housing 220, for example by screwing it on. A cable passage of the terminal cover 619 projects radially and corresponds to the grommet 269 in the slot-like recess of the sensor hood 361.

[0056] Fig. 3 schematically shows an alternative embodiment of the sensor mounting and the housing-forming part, which is designed as a stamped sheet metal part 651, in a perspective exploded view. The stamped sheet metal part 651 has a hexagonal base surface. At every second edge of the hexagonal base surface, a rectangular wing is bent at approximately a right angle and thus extends in the axial direction. An end region of the wing is again bent at a right angle, so that the end region projects outwards approximately parallel to the base surface. A through-hole is machined into this end region through which a cage screw 659 is guided, which is screwed into a cage nut 651. The cage nut 651 is attached to the grid structure of the fan housing 35, in particular inserted into the grid structure from the bearing shield side. With the stamped sheet metal part attached, the end region of the wing lies flush against the grid structure of the fan housing 35.The base completely covers the transmitter housing when viewed from an axial perspective.

[0057] The cable entry of the connection cover 619 of the encoder 219 protrudes radially between two wings. The advantage of this embodiment lies in the smaller size of the electric motor 50 with encoder 219, as well as in reduced material consumption and weight. Furthermore, the encoder 219 is easier to connect to a controller. The vibration behavior of the fan housing 35, and thus the noise generated when the fan 36 is running, is reduced by the mounted encoder 219. QUOTES INCLUDED IN THE DESCRIPTION

[0058] This list of documents cited by the applicant was generated automatically and is included solely for the convenience of the reader. The list does not form part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0059] - DE 102005009601

[0002]

Claims

[1] electric motor comprising a rotor having a shaft, a housing and an encoder, where the shaft is mounted in the housing by means of a fixed bearing and a floating bearing, wherein the floating bearing is arranged so that it can move axially and the shaft has shaft sections with different diameters, as a result of which the transitions between the shaft sections form shaft diameter steps, wherein a spring element is arranged between the movable bearing and a housing part, in particular an end shield, at least one ring of the floating bearing being pressed by the spring element against a shaft diameter step, wherein the housing comprises a stator housing which encloses a stator and which has parallel cooling fins protruding radially from the stator housing, wherein the encoder has an encoder shaft non-rotatably connected to a shaft of the electric motor and an encoder housing non-rotatably connected to a housing of the electric motor, wherein the transmitter housing is at least partially surrounded by a housing-forming part, wherein the encoder housing is attached to a fan hood of the electric motor that surrounds a fan wheel and forms a housing, with the fan wheel running, an air stream in the axial direction flows unhindered past the housing-forming part or through the housing-forming part, the housing-forming part being attached to the fan shroud, whereby the encoder shaft is designed as an expanded shaft and is non-positively connected to the shaft. [2] electric motor with one encoder, wherein the encoder has an encoder shaft non-rotatably connected to a shaft of the electric motor and an encoder housing non-rotatably connected to a housing of the electric motor, characterized in that the transmitter housing is at least partially surrounded by a housing-forming part. [3] Electric motor according to claim 2, characterized in that the transmitter housing is attached to a fan cover of the electric motor surrounding a fan wheel to form a housing, wherein when the fan wheel is running an air flow in the axial direction flows unhindered past the housing-forming part or through the housing-forming part. [4] Electric motor according to claim 3, characterized in that the housing-forming part is attached to the fan shroud. [5] Electric motor according to claim 2, 3 or 4, characterized in that the encoder shaft is designed as an expanding shaft and is non-positively connected to the shaft. [6] Electric motor according to one of claims 2 to 5, characterized in that the encoder housing is outside the fan cover. [7] Electric motor according to one of claims 2 to 6, characterized in that the transmitter housing is supported via a support element on the bearing plate. [8] Electric motor according to one of claims 2 to 7, characterized in that the housing-forming part is designed as a transmitter cover, which has a cylindrical lateral surface. [9] Electric motor according to claim 8, characterized in that an axial cross-section of the encoder cover has an n-fold discrete rotational symmetry, where n is an integer greater than two, in particular n is four [10] Electric motor according to claim 8 or 9, characterized in that the encoder cover has the shape of a shell with a quadrangular peripheral surface whose four corners are rounded, with a bottom of the encoder cover having recesses. [11] Electric motor according to claim 7 or 8, characterized in that the encoder cover is pushed onto the fan cover in a clamping manner. [12] Electric motor according to one of claims 2 to 7, characterized in that the housing-forming part is designed as a stamped sheet metal part. The electric motor according to claim 12, characterized in that the stamped sheet metal part has a hexagonal base surface, a quadrangular wing is bent approximately at right angles on every second edge of the hexagonal base surface, and an end region of the wing is bent at right angles so that it is approximately parallel to the protrude outwards. [14] Electric motor according to claim 12 or 13, characterized in that the stamped sheet metal part is attached to the fan cowl. [15] Electric motor according to claim 13, characterized in that the end portions of the blades have through holes through which cage screws are passed and the cage screws are screwed into cage nuts which are fixed to the fan cowl.

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