Electric motor comprising a stator and a rotor, and method for manufacturing an electrically driven machine

Abstract

electric motor comprising a stator and a rotor, wherein the rotor has a rotor shaft (7) and a ring part (13) which is non-rotatably connected to the rotor shaft (7), wherein the stator comprises a stator housing and a flange part (1) connected to the stator housing, wherein a first conical surface section is formed on the ring part (13) and a second conical surface section is formed on the flange part (1), wherein the alignment and centering of the rotor relative to the stator can be fixed by pressing the first cone surface section against the second cone surface section, wherein the rotor is axially displaceable relative to the stator, the axial displacement in the axial direction is limited by the contact of the two conical surface sections with each other, wherein the flange part (1) is connected to a braking device, the braking device is electromagnetically actuated, wherein the braking device has an electromagnet and an armature disk which is fixedly connected to the stator and the electromagnet but axially movable, and which is pressed away from the electromagnet by a spring element onto a brake pad carrier part which is fixedly but axially movable to the rotor shaft (7), wherein the rotor has a drive toothing or the rotor is rotationally fixed to a part having a drive toothing, wherein a brake pad carrier is rotationally fixed but axially displaceable to the rotor, wherein the brake pad carrier has an internal toothing which engages with the drive toothing, where the axial length of the drive teeth exceeds the sum of the axial working range during operation of the brake and the axial displacement.

Description

[0001] The invention relates to an electric motor comprising a stator and a rotor, and a method for manufacturing an electrically driven machine.

[0002] It is generally known that an electric motor has a rotor that is rotatably mounted to a stator of the electric motor. The rotor's bearings are located within the electric motor.

[0003] A direct drive is known from DE 10 2006 040 611 A1.

[0004] A fast-acting brake for dynamo-electric machines is known from US patent 2,879,417 A.

[0005] The invention is therefore based on the objective of further developing an electric motor, whereby waste heat from the rotor bearing is to be saved.

[0006] According to the invention, the problem is solved in the electric motor comprising a stator and a rotor according to the features specified in claim 1 and in the method for manufacturing an electrically driven machine according to the features specified in claim 8.

[0007] Key features of the invention in the electric motor are that it has a stator and a rotor, wherein the rotor has a rotor shaft and a ring part which is non-rotatably connected to the rotor shaft, wherein the stator comprises a stator housing and a flange part connected to the stator housing, wherein a first conical surface section is formed on the ring part and a second conical surface section is formed on the flange part, wherein the alignment and centering of the rotor relative to the stator can be fixed by pressing the first cone surface section against the second cone surface section.

[0008] An advantage of this design is that a bearingless electric motor can be constructed, whereby the rotor's position relative to the stator can be fixed by pressing the conical surface sections together. This allows the electric motor to be fixed and transported after manufacturing. However, in this manufactured state, the rotor is fixed to the stator. Only after connecting the electric motor to a driven machine, which has a housing and a rotatable component mounted therein, particularly a shaft, is the rotor released and thus rotatably mounted relative to the stator.

[0009] In an advantageous embodiment, the first cone surface section is an external cone surface section and the second cone surface section is an internal cone surface section, or vice versa. In particular, the cone angle of the two cone surface sections is essentially the same. An advantage of this is that the rotor can be aligned with particularly high accuracy using the cone surfaces.

[0010] In an advantageous embodiment, the rotor is axially displaceable relative to the stator. The axial displacement is limited by the contact of the two conical surface sections. An advantage of this design is that an axial displacement is possible to detach the rotor from the stator, so that the two conical surfaces no longer touch and the rotor can therefore rotate freely relative to the stator.

[0011] In an advantageous embodiment, the ring part has threaded bores into which a screw part can be screwed, wherein the screw part is guided through a recess in the flange part. in particular wherein the screw part is a screw whose screw head rests on the outer surface of the flange part and which is partially screwed into one of the threaded holes, In particular, the threaded bores are axially oriented, i.e., parallel to the rotor axis. An advantage of this is that a screw connection allows the rotor to be pressed against the stator, so that the conical surface sections abut each other and thus the alignment and centering of the rotor relative to the stator can be fixed.

[0012] In an advantageous embodiment, the rotor can be screwed onto the stator in such a way that the first conical surface section rests against the second conical surface section. An advantage of this is that the orientation of the rotor relative to the stator can be fixed.

[0013] In a preferred embodiment, the ring section is screwed to the rotor's laminated core. This design offers the advantage of simple attachment to the laminated core.

[0014] Alternatively, the ring section is screwed to the rotor's laminated core or integrally formed with the laminated core as a suitably shaped laminated core. Advantageously, the screw connection or a similarly effective connection is thus provided within this one-piece laminated component.

[0015] In an advantageous embodiment, the flange part is connected to a braking device, in particular wherein the braking device is electromagnetically actuated, In particular, the braking device comprises an electromagnet and an armature disk that is fixedly connected to the stator and the electromagnet but axially movable. A spring element presses the armature disk away from the electromagnet and onto a brake pad carrier that is fixedly but axially movable to the rotor shaft. An advantage of this design is that the braking device can be pre-assembled and mounted on the motor. The rotor has at least one drive tooth with which a brake pad carrier is fixedly but axially displaceable. Since the rotor is axially displaced to release the fixed connection to the stator, the braking device must have a greater axial tolerance than comparable braking devices that are installed in or attached to motors with a rotor mounted directly in the stator.

[0016] In an advantageous embodiment, the rotor has a drive tooth or the rotor is connected in a rotationally fixed manner to a part having a drive tooth. wherein a brake pad carrier is connected to the rotor in a rotationally fixed but axially displaceable manner, wherein the brake pad carrier has an internal toothing which engages with the drive toothing, where the axial length of the drive teeth exceeds the sum of the axial working range during brake operation and the axial displacement. An advantage of this is that the axial tolerance is thus greater than the tolerance for brake devices that are mounted on or connected to a rotor supported by the stator.

[0017] In an advantageous embodiment, the ring section is arranged radially within the stator winding and connected to the stator lamination stack. An advantage of this design is that a compact device can be produced.

[0018] In an advantageous embodiment, the rotor shaft is connected to a driven shaft by means of a further clamping set, The further clamping assembly comprises a bushing arranged between the shaft, which has a hollow shaft section, and the rotor shaft. This bushing has an oil-filled chamber which is pressurized by actuating a screw to such an extent that the bushing is elastically deformed, thus creating a frictional connection between the shaft and the hollow shaft section. An advantage of this design is that a frictional connection with the driven shaft of the machine can be established quickly and easily.

[0019] Important features of the process for manufacturing an electrically driven machine are that - in a first process step the rotor is received in a positioning aid part connected to the stator housing of the stator, wherein the positioning aid part positions and aligns the rotor relative to the stator housing and wherein the positioning aid part is centered and aligned on the stator housing part, - in a subsequent process step, the rotor is screwed to the stator by means of screw parts, in particular screws, in particular wherein the screw axis of the screw parts is aligned in the axial direction, in particular in the axial direction, whereby the two conical surface sections are brought into contact with each other, and thus the rotor is aligned and centered relative to the stator, - in a subsequent process step, the positioning aid part is removed, - in a subsequent process step the rotor is connected to a hollow shaft section of a driven shaft, in particular a machine, and the stator housing is connected to a housing, in particular of the machine, in which the shaft is mounted, - in a subsequent process step the screw connection between rotor and stator is loosened, the rotor is axially displaced, in particular under the influence of magnetic forces of the permanent magnets arranged on the rotor, and then the rotor is connected to the shaft to be driven, in particular by means of a clamping device, in particular by means of a hydraulically actuated clamping device.

[0020] A key advantage is that a bearingless electric motor drive can be manufactured and delivered with the corresponding radial alignment of the rotor to the stator, making it transportable. After installation in the driven machine, the electric motor can be operated, and the rotor is supported by bearings within the driven machine. In particular, the rotor is thus supported on one side only within the driven machine. This eliminates the need for bearings and therefore the associated heat generation.

[0021] In an advantageous embodiment, the connection of the rotor to the hollow shaft section of the shaft to be driven is carried out by means of the clamping set. in particular wherein the clamping set is a hydraulic clamping set which is integrated into a bushing, In particular, an oil-filled chamber is surrounded by the bushing material and can be pressurized to such an extent that the radial width of the bushing is variable. A key advantage is the particularly simple connection process. Furthermore, the clamping assembly can be fitted onto the rotor shaft before transport, especially with a precision fit. This allows for quick installation in the machine being driven.

[0022] 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.

[0023] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows an electric motor according to the invention.

[0024] In this case, the rotor shaft 7 is not mounted in the motor housing 12.

[0025] A laminated core is arranged on the rotor shaft 7, to which permanent magnets are attached, in particular by adhesive bonding. The rotor shaft 7 can be connected in a rotationally fixed manner to a driven shaft of a machine to be connected by means of the clamping device 6, and the rotor shaft is then supported by this shaft during operation.

[0026] The stator of the electric motor has a stator winding which is inserted into slots of a laminated core 4. The laminated core 4 is screwed to a motor housing 12. Alternatively, the motor housing 12 can also be shrink-fitted onto the laminated core 4.

[0027] A flange part 1 is connected to the essentially hollow cylindrical motor housing 12, in particular by screws.

[0028] During the manufacture of the motor, the stationary part of an electromagnetically actuated brake device is connected to the flange part 1. This part includes, in particular, the coil core 8 and the coil winding 9, i.e., the brake coil, which is received in an annular groove formed in it.

[0029] A conical surface section 10 is formed on the inside of the flange part 1. This conical surface section 10 is designed as an outer conical surface section of the flange part 1.

[0030] At the axial end region of the sheet metal stack 14, in particular at the axial end region of the sheet metal stack 14 facing the flange part 1, a ring part 13 is arranged which has a conical surface section which is formed as an inner conical surface section.

[0031] The ring part 13 is preferably screwed to the sheet metal stack 14 and / or made of steel.

[0032] The rotor, in particular the ring part 13, is screwed to the flange part 1 by means of the screws 3 which pass axially through the flange part 1. The screws 3 are each screwed into an axially oriented threaded bore in the ring part 13, with the screw heads bearing against the outer surface of the flange part 1. Thus, as the screws are tightened, the rotor is drawn towards the flange part 1 until the conical surface section 10 of the flange part 1 abuts the conical surface section of the ring part 13. The rotor is thereby centered and aligned by means of the abutting conical surface sections.

[0033] Additionally, a centering device can be used, which aligns and centers the rotor relative to the stator before the rotor is screwed onto the stator using screws 3. For this purpose, the centering device is placed on the stator on the axial side of the stator facing away from the brake device, with the rotor held in the centering device. After the rotor is screwed onto the stator using screws 3, the centering provided by the centering device is fixed by the conical surface sections pressing against each other, and the centering device can then be removed.

[0034] In this way, the unsupported rotor is fixed to the stator and the electric motor is transportable, being aligned and centered by means of the conical surface sections.

[0035] To be mounted on a machine driven by an electric motor, the rotor is connected to a hollow shaft of the driven machine in a rotationally fixed manner, in particular by means of a clamping device 6, which is mounted on the rotor shaft 7, especially with a precision fit. Preferably, the clamping device 6 is designed as a hydraulic coupling, i.e., as a bushing which has an oil-filled cavity that can be deformed by actuating a screw such that the radial wall thickness of the bushing increases. This enables a friction-fit connection with the hollow shaft mounted on the bushing.

[0036] The stator, in particular the flange part 1, is connected to the housing of the machine in a rotationally fixed manner during installation, preferably by means of screws.

[0037] The screws 3 are loosened during installation so that the rotor can rotate relative to the stator after axial displacement. This axial displacement is preferably caused by the weight of the rotor and / or by the magnetic force generated by the permanent magnets 5, which attracts the rotor towards the machine. The axial displacement is limited by a diameter step on the bushing, which abuts the hollow shaft of the machine to be driven. The bushing itself axially limits the rotor shaft 7 by bearing against a step on the rotor shaft.

[0038] The braking device has an armature disk which is fixed to the coil core 8 but axially movable, i.e., in the direction of the rotor axis. When the brake coil 9 is energized, the armature disk is attracted towards the coil core 8 against the spring force generated by a spring element. When the energized coil is de-energized, the spring element presses the armature disk against a brake pad carrier fitted with brake pads. This carrier is fixed to the rotor shaft but axially displaceable. For this purpose, the rotor shaft has external teeth, either integrated into the rotor shaft or mounted on a bushing that is fixed to the rotor shaft. The brake pad carrier has internal teeth that mesh with the external teeth. Both teeth are straight-cut, i.e., without helix angles, thus allowing the brake pad carrier to be axially displaceable on the rotor shaft while remaining fixed to it.The brake pad carrier is axially fitted with brake pads on both sides, so that when the brake coil 9 is not energized, the armature disc is pressed against a brake pad on the side of the brake pad carrier facing the armature slide. The other side of the brake pad carrier is pressed against a braking surface formed on the flange part 1, i.e., a ground, milled, or otherwise finely machined surface section of the flange part 1.

[0039] During operation, i.e., with alternating energization and de-energization, the brake pad carrier requires an axial working range, and therefore the drive teeth are designed to be sufficiently long axially. The axial length of the drive teeth corresponds to the sum of the axial working range (stroke) and the axial extension of the brake pad carrier. Reference symbol list 1 flange part 2. Recess for cable routing 3 screws 4 Stator stator lamination stack 5 permanent magnets 6 Clamping device, in particular hydraulic clamping device 7 Rotor shaft 8 Coil core of the brake coil 9 Brake coil 10 cone surface 11 Groove for pull rod 12 Motor housings 13 Ring part, in particular steel ring part 14 sheet metal package

Claims

[1] Electric motor comprising a stator and a rotor, wherein the rotor has a rotor shaft (7) and a ring part (13) which is non-rotatably connected to the rotor shaft (7), wherein the stator comprises a stator housing and a flange part (1) connected to the stator housing, wherein a first conical surface section is formed on the ring part (13) and a second conical surface section is formed on the flange part (1), wherein the alignment and centering of the rotor relative to the stator can be fixed by pressing the first cone surface section against the second cone surface section, wherein the rotor is axially displaceable relative to the stator, the axial displacement in the axial direction is limited by the contact of the two conical surface sections with each other, wherein the flange part (1) is connected to a braking device, the braking device is electromagnetically actuated, wherein the braking device has an electromagnet and an armature disk which is fixedly connected to the stator and the electromagnet but axially movable, and which is pressed away from the electromagnet by a spring element onto a brake pad carrier part which is fixedly but axially movable to the rotor shaft (7), wherein the rotor has a drive toothing or the rotor is rotationally fixed to a part having a drive toothing, wherein a brake pad carrier is rotationally fixed but axially displaceable to the rotor, wherein the brake pad carrier has an internal toothing which engages with the drive toothing, where the axial length of the drive teeth exceeds the sum of the axial working range during operation of the brake and the axial displacement. [2] Electric motor according to claim 1, characterized bythat the first cone surface section is an external cone surface section and the second cone surface section is an internal cone surface section or vice versa. [3] Electric motor according to at least one of the preceding claims, characterized by , that the ring part (13) has threaded bores into which a screw part can be screwed, wherein the screw part is guided through a recess (2) of the flange part (1). [4] Electric motor according to at least one of the preceding claims, characterized by , that the rotor can be screwed onto the stator in such a way that the first conical surface section rests against the second conical surface section. [5] Electric motor according to at least one of the preceding claims, characterized by , that the ring part (13) is screwed to the laminated core (14) of the rotor or is integrally formed with the laminated core (14) as a correspondingly shaped laminated core (14). [6] Electric motor according to at least one of the preceding claims, characterized by , that the ring part (13) is arranged radially inside the stator winding and is connected to the rotor lamination stack of the stator. [7] Electric motor according to at least one of the preceding claims, characterized by , that the rotor shaft (7) is connected to a driven shaft by means of a further clamping set, wherein the further clamping set comprises a bushing arranged between shaft having a hollow shaft section and rotor shaft (7), which has an oil-filled space which is subjected to pressure by actuating a screw such that the bushing is elastically deformed in such a way that the shaft and hollow shaft section are frictionally connected. [8] Method for manufacturing an electrically driven machine, characterized by , that - in a first process step the rotor is received in a positioning aid part connected to the stator housing of the stator, wherein the positioning aid part positions and aligns the rotor relative to the stator housing and wherein the positioning aid part is centered and aligned on the stator housing part, - in a subsequent process step, the rotor is screwed to the stator using screw parts, thereby bringing the two conical surface sections into contact with each other, and thus aligning and centering the rotor relative to the stator, - in a subsequent process step, the positioning aid part is removed, - in a subsequent process step the rotor is connected to a hollow shaft section of a driven shaft and the stator housing is connected to a housing in which the shaft is supported, - in a subsequent process step the screw connection between rotor and stator is loosened, the rotor is moved axially and then the rotor is connected to the shaft to be driven by means of a clamping device (6). [9] Method according to at least one of the preceding claims, characterized by , that the connection of the rotor to the hollow shaft section of the shaft to be driven is carried out by means of the clamping set.

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