Electric motor having a stator and a rotatably mounted rotor radially surrounded by the stator

Abstract

The invention relates to an electric motor having a stator and a rotatably mounted rotor radially surrounded by the stator, wherein the stator has a laminated stator core, a stator winding and two end caps for insulating the windings, wherein each end cap has a base ring on which radially inwardly protruding bridges are formed, each of which carries a respective head region of the end cap at the radially inner end region of the bridge, wherein teeth protruding radially inwardly are formed on the laminated stator core, a respective winding being wound around the respective tooth neck of said teeth together with the respective bridges of the two end caps resting against the tooth neck, wherein in the radial spacing region covered in the radial direction by the respective tooth neck, the region covered in the circumferential direction by the respective end cap is larger than the region covered in the circumferential direction by the respective tooth neck.

Description

[0001] Electric motor with a stator and a rotatably mounted component radially surrounded by the stator

[0002] rotor

[0003] Description:

[0004] The invention relates to an electric motor with a stator and a rotatably mounted rotor radially surrounded by the stator.

[0005] It is generally known that the stator winding of an electric motor must be electrically insulated from parts leading to ground.

[0006] From CN 1 06 059 155 B, an electric motor with a stator is known as the closest prior art.

[0007] A stator is known from JP 2023 - 48 366 A.

[0008] From DE 102019 118 633 A1 a stator body for an electric machine is known.

[0009] A compressor with a stator is known from WO 2023 / 007 644 A1.

[0010] A stator lamination stack with teeth is known from CN 1 12 018 922 A.

[0011] A motor with stator insulation is known from JP 2004 - 208 387 A.

[0012] An electric motor is known from DE 102015 106 186 A1.

[0013] The invention is therefore based on the objective of further developing an electric motor for cost-effective and simple manufacturing.

[0014] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1.Important features of the invention for the electric motor with a stator and a rotatably mounted rotor radially surrounded by the stator are that the stator has a stator lamination stack, a stator winding and two end caps, in particular wherein the stator lamination stack is arranged between the end caps, wherein each end cap has a base ring on which radially inwardly projecting webs are formed, which at their radially inner end region each support a respective head region of the end cap, wherein radially inwardly projecting teeth are formed on the stator lamination stack, the respective tooth neck together with the webs of the two end caps abutting it is wound by a respective winding, in particular wherein the number of tooth necks is equal to the number of webs, the webs are uniformly spaced apart from each other in the circumferential direction and / or the tooth necks are uniformly spaced apart from each other in the circumferential direction.

[0015] - wherein in the radial spacing area covered in the radial direction by the respective tooth neck, the area covered in the circumferential direction by the respective end cap is larger than the area covered in the circumferential direction by the respective tooth neck, in particular and includes this area, and / or wherein in the radial spacing area covered in the radial direction by the respective tooth neck, the area covered in the circumferential direction by the respective web of the respective end cap includes the area covered in the circumferential direction by the respective tooth neck, in particular wherein the radial spacings are the distances to the axis of rotation of the rotor, the radial direction is relative to the axis of rotation of the rotor, the circumferential direction is relative to the axis of rotation of the rotor and / or the axial direction is aligned parallel to the axis of rotation of the rotor,The respective end cap is fitted onto the stator lamination stack and elastically pre-tensioned to create a force-fit connection between the end cap and the stator lamination stack. An advantage of this design is that no insulating paper is required for insulating the winding; instead, the end cap itself, along with air gaps, ensures the necessary insulation strength. This is because the end cap rests against the last individual lamination of the stator lamination stack, i.e., the adjacent lamination, and protrudes axially only with its centering rib and wall.to be clamped to the stator lamination stack. The end cap rests against the last individual lamination and extends over several laminations into the stator chamber. The circumferential overhang of the end cap ensures the air gap between the tooth necks and the winding. In this way, the required insulation strength is provided. The end cap is preferably made of an electrically insulating material, in particular plastic, and especially as a plastic injection-molded part.

[0016] According to the invention, an axial protrusion of the end cap along the tooth necks is avoided, thus providing the largest possible space for the winding.

[0017] The tooth necks are spaced apart from each other in the circumferential direction; the webs are also spaced apart from each other in the circumferential direction.

[0018] In an advantageous embodiment, the winding is spaced from the tooth neck by an air gap, particularly in the axial region between the two end caps, and especially in the circumferential direction. It is advantageous that the tension on the winding wires ensures this spacing from the tooth neck. This is because the winding wires, running along a straight line, connect the circumferentially projecting areas of the end caps, thus spacing this straight line from the respective tooth neck.

[0019] In an advantageous embodiment, the respective end cap, including its ribs and head area, is manufactured as a single-piece, particularly one-piece, injection-molded plastic part. This offers the advantage of simple and cost-effective manufacturing. In another advantageous embodiment, the tooth head of each tooth is widened circumferentially, particularly with respect to the tooth neck supporting the tooth head. It is advantageous that the winding is limited radially inwards.

[0020] In an advantageous embodiment, the stator lamination stack has an annular base body on which radially inwardly projecting teeth are formed. Each tooth has a tooth head supported by its respective tooth neck. The tooth head of each tooth is located at the radially inner end region of the tooth and is formed with a circumferential widening such that the area covered by the tooth head in the circumferential direction includes the area covered by the tooth neck in the circumferential direction. This design is advantageous because the magnetic field guidance can be optimized and the winding is held stable.

[0021] In an advantageous embodiment, axially projecting centering walls are formed on the base ring of each end cap. These walls bear against the radially inner side of the annular base body of the stator lamination stack and are pressed against it with elastic preload. The advantage of this design is that the end cap can be clamped and simultaneously centered on the stator lamination stack by relative tension between the centering wall and the centering ridges. In particular, the rotational position of the end caps is defined by the centering walls, because each centering wall extends circumferentially to such an extent that it abuts the tooth necks of the stator lamination stack at both of its end regions.

[0022] In an advantageous embodiment, axially projecting centering ridges are formed on the respective head region of each end cap. These ridges bear against the radially outer side of the respective tooth head of the stator lamination stack and are pressed against it, in particular, under elastic preload. An advantage of this design is that the end cap can be clamped to the stator lamination stack by clamping the centering ridges against the centering walls.

[0023] In an advantageous embodiment, the webs of the end caps each rest against the respective tooth necks of the stator lamination stack, in particular the individual lamination of the stator lamination stack most adjacent to each end cap, and in particular, lie flat against them, wherein the area covered by the webs in the axial direction adjoins the area covered by the tooth necks in the axial direction, and in particular does not overlap. It is advantageous that, although the webs of the end caps are wider in the circumferential direction than the tooth necks, the contact surface between the tooth necks and the webs is in each case purely flat. In particular, the webs only contact the respective adjacent individual lamination of the stator lamination stack, without overlapping with the stator lamination stack in the axial direction.

[0024] In an advantageous embodiment, the respective base ring of the respective end cap has recesses, in particular indentations, on its side facing the stator lamination stack. The advantage here is that the elasticity is increased, thus enabling the end cap to be slid onto the stator lamination stack with minimal effort.

[0025] In an advantageous embodiment, the recesses are arranged such that the area covered by the respective centering wall in the circumferential direction encompasses the area covered by the respective recess in the circumferential direction. It is advantageous that the recesses are therefore less extensive in the circumferential direction than the centering wall. Thus, stability can be ensured and elasticity can be achieved in a defined manner.

[0026] In an advantageous embodiment, the centering walls are radially spaced from the recesses. It is advantageous that the wall thickness of the base ring is sufficiently robust.

[0027] In an alternative advantageous embodiment, the centering walls border the recesses radially, meaning they do not overlap radially. An advantage of this is that the elasticity of the base ring is increased, allowing the respective centering wall to be deflected with minimal force.

[0028] In an advantageous embodiment, the base ring is designed with a circumferential annular groove that opens towards the stator lamination stack. An advantage of this is that the centering wall can be deflected sufficiently with lower forces.

[0029] In an advantageous embodiment, the teeth of the stator lamination stack are straight-cut. It is advantageous that the respective centering rib must project from the end cap without any helix angle. 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 be apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0030] The invention will now be explained in more detail with reference to schematic illustrations:

[0031] Figure 1 schematically shows a section through a tooth of a stator of an electric motor according to the invention.

[0032] Figure 2 shows a sectioned view of the stator without winding 3 and is shown in an oblique view.

[0033] Figure 3 shows an end cap 2 in oblique view.

[0034] Figure 4 shows the stator in axial section in oblique view, so that remnants of the end cap 2 are visible.

[0035] Figure 5 shows a corresponding top view of the sectioned stator.

[0036] As shown in the figures, the electric motor according to the invention has a stator which has a stator lamination stack designed as a stack of individual laminations with end caps 2 attached to the axial end faces of the stator lamination stack.

[0037] The electric motor has a rotor that is rotatably mounted relative to the stator, with the rotor being supported by bearings housed in flange sections. The stator lamination stack is arranged axially between the two flange sections.

[0038] Optionally, the stator lamination stack is inserted into a hollow stator housing, which is connected to the flange components. The rotor is preferably equipped with permanent magnets, allowing the electric motor to be operated as a synchronous motor.

[0039] The end caps 2 are each made of electrically insulating material, in particular plastic.

[0040] The stator lamination stack has an annular base body 1, in particular a yoke ring, from which regularly spaced teeth project radially inwards in the circumferential direction. Each tooth has a circumferentially widened tooth head at its radially inner end region. The respective tooth head is held by a tooth neck that attaches to the base body 1. The tooth head, tooth neck, and base body 1 are formed as a single unit, in particular as a single piece, on each individual lamination. The entire stator lamination stack, including its base body 1 and its teeth, is thus designed as a lamination stack.

[0041] Each tooth is wrapped with a winding 3, which is held at a distance from the individual metal sheets by the end caps 2. In this way, electrical insulation distances are maintained.

[0042] The end caps 2 are spaced apart from each other in the axial direction, in particular parallel to the axis of rotation of the rotor of the electric motor.

[0043] Since the winding of the stator is carried out with a winding wire that is constantly kept under tension, the winding 3 produced in this way is pre-tensioned, in particular, held under tension.

[0044] As shown in Figure 1, the end caps 2 project beyond the tooth necks of the stator lamination stack, both circumferentially and counter-circumferentially. The winding wire is deflected by each end cap 2 and is thus kept spaced away from the respective metallic tooth neck of the stator lamination stack.

[0045] For this purpose, the respective end cap 2 is attached to the stator lamination stack from the axial direction. The end cap 2 lies flush against the respective tooth neck, but projects radially outwards beyond the tooth head. These projecting areas are formed as centering ribs 30 and also protrude axially, bearing against the stator lamination stack, particularly on the radially outer side of the tooth heads, and in particular bearing against it with axial preload.

[0046] Furthermore, a centering wall 31 protrudes from the respective end cap 2, which extends radially inwards beyond the annular base body 1 and rests against its radial inner side, since the centering wall 31 protrudes in the axial direction.

[0047] Since the centering wall 31, particularly when viewed from the stator lamination stack, projects radially inwards beyond the base body 1, and the centering ridges 30 project radially outwards beyond the respective tooth tip, the end cap 2 clamps itself firmly onto the stator lamination stack and holds the winding wire, which is under tension, at a distance from the metallic stator lamination stack. Furthermore, the rotational position of the end cap 2 is determined by the centering ridges 30, each of which engages in a tooth gap of the stator lamination stack.

[0048] The end cap 2 has a base ring 32 on which radially inwardly projecting ribs 20 are formed, which open into circumferentially widened head regions 21 and hold them. The end cap 2, including its ribs 20 and head regions 21, is preferably manufactured as a plastic injection-molded part.

[0049] The webs 20 of the end cap 2 are wider in the circumferential direction than the tooth necks of the stator lamination stack. Thus, the webs 20 project beyond the tooth necks in the circumferential direction and against the circumferential direction, whereby the winding 3, which is deflected by the end cap 2 and extends axially further to the second end cap 2, remains spaced away from the tooth neck.

[0050] In the axial direction, the end cap 2 overlaps the stator lamination stack only with its centering ribs 30 and centering walls 21. Otherwise, the end cap 2 rests flush and / or flat against the stator lamination stack with its axial end face, in particular against the end plate of the stator lamination stack nearest to it. The contact surface is flat, and its normal direction is parallel to the axial direction.

[0051] The advantage here is that the available winding space for winding 2 is only slightly restricted and no insulating paper is required for winding 2. Therefore, compared to conventional motors, insulating paper is not needed during manufacturing, yet the electric motor still has sufficient insulation resistance after winding.

[0052] Radially inwards, the end cap 2 is limited to the same or a larger maximum clear inner diameter than the stator lamination stack. Thus, the free movement range available to the rotor in the radial direction is not restricted by the end cap 2, but rather determined by the stator lamination stack.

[0053] To facilitate clamping the end cap 2, the base ring 32 of the end cap 2 has recesses, in particular indentations, on its side facing the stator lamination stack. These recesses are arranged such that the area covered circumferentially by the respective centering wall 31 encompasses the area covered circumferentially by the respective recess. This facilitates elastic deflection of the centering walls 31 and thus also facilitates clamping the end cap 2 to the stator lamination stack.

[0054] To safely limit the radial inwards of the winding 3, the head area 21 protrudes axially on its side facing away from the stator lamination stack.

[0055] The centering ribs 30 each project axially towards the stator lamination stack at the respective head region 21 in order to bear against the radially outer side of the head regions 30 and press against them with preload. The respective centering wall 31 presses against the radial inner side of the annular base body 1.

[0056] In Figure 4, the cutting plane intersects the end cap 2, so that a cut remnant of the centering ribs 30 and a cut remnant of the centering walls 31 are visible.

[0057] The recesses are located on the side of the respective end cap 2 facing the stator lamination stack, but not on the side facing away from the stator.

[0058] In further embodiments according to the invention, the base ring is designed with a circumferential annular groove which is open towards the stator lamination stack.

[0059] Reference symbol list

[0060] 1 ring-shaped base body, in particular yoke ring, of the stator lamination stack 2 end cap

[0061] 3 windings

[0062] 4 air gap

[0063] 20 Bridge

[0064] 21 Head area 30 Centering bridge

[0065] 31 Centering wall

[0066] 32 Base ring

Claims

Patent claims:

1. Electric motor with a stator and a rotatably mounted rotor radially surrounded by the stator, wherein the stator comprises a stator lamination stack, a stator winding and two end caps, in particular wherein the stator lamination stack is arranged between the end caps, wherein each end cap has a base ring on which radially inwardly projecting webs are formed, which at their radially inner end region each support a respective head region of the end cap, wherein radially inwardly projecting teeth are formed on the stator lamination stack, the respective tooth necks of which, together with the webs of the two end caps abutting it, are wound by a respective winding, in particular wherein the number of tooth necks is equal to the number of webs, the webs are uniformly spaced apart from each other in the circumferential direction and / or the tooth necks are uniformly spaced apart from each other in the circumferential direction.wherein in the radial spacing area covered by the respective tooth neck in the radial direction, the area covered in the circumferential direction by the respective end cap is larger than the area covered by the respective tooth neck in the circumferential direction, in particular and encompassing this area, in particular wherein the radial spacings are the distances to the axis of rotation of the rotor, the radial direction is relative to the axis of rotation of the rotor, the circumferential direction is relative to the axis of rotation of the rotor and / or the axial direction is aligned parallel to the axis of rotation of the rotor.

2. Electric motor according to claim 1, characterized in that the respective end cap is placed on the stator lamination stack and elastically prestressed to force-fit connection of the end cap with the stator lamination stack.

3. Electric motor according to claim 1 or 2, characterized in that the winding is spaced apart from the end cap and by an air gap to the tooth neck, in particular wherein the air gap spaced the winding apart from the tooth neck in the axial area located between the two end caps, in particular in the circumferential direction.

4. Electric motor according to one of the preceding claims, characterized in that the respective end cap together with its webs and head area is manufactured as a one-piece, in particular one-piece, plastic injection molded part.

5. Electric motor according to one of the preceding claims, characterized in that the respective tooth head of the respective tooth is widened in the circumferential direction, in particular with respect to the respective tooth neck bearing the respective tooth head.

6. Electric motor according to one of the preceding claims, characterized in that the stator lamination stack has an annular base body on which the radially inwardly projecting teeth are formed, each having a respective tooth head supported by the respective tooth neck, wherein the respective tooth head of the respective tooth is arranged at the radially inner end region of the respective tooth and is formed in such a circumferentially widened manner that the area covered in the circumferential direction by the tooth head contains the area covered in the circumferential direction by the respective tooth neck.

7. Electric motor according to one of the preceding claims, characterized in that axially projecting centering walls are formed on the base ring of each end cap, which each bear against the radially inner side of the annular base body of the stator lamination stack, in particular and elastically prestressed.

8. Electric motor according to one of the preceding claims, characterized in that axially projecting centering ribs are formed on the respective head region of each end cap, which each bear against the radially outer side of the respective tooth head of the stator lamination stack, in particular and elastically pre-tensioned.

9. Electric motor according to one of the preceding claims, characterized in that the webs (20) of the end caps each bear against respective tooth necks of the stator lamination stack, in particular the individual lamination of the stator lamination stack that is nearest to the respective end cap, in particular lying flat, wherein the area covered by the webs (20) in the axial direction is adjacent to the area covered by the tooth necks in the axial direction, in particular and does not overlap.

10. Electric motor according to one of the preceding claims, characterized in that the respective base ring of the respective end cap has recesses, in particular recesses, on its side facing the stator lamination stack.

11. Electric motor according to one of the preceding claims, characterized in that the recesses are arranged such that the area covered by the respective centering wall in the circumferential direction includes the area covered by the respective recess in the circumferential direction.

12. Electric motor according to one of the preceding claims, characterized in that the centering walls are radially spaced from the recesses or that the centering walls are radially adjacent to the recesses, in particular not radially overlapping.

13. Electric motor according to one of the preceding claims, characterized in that the base ring is designed with a circumferentially circumferential annular groove which is open towards the stator lamination stack, and / or that the teeth of the stator lamination stack are arranged in a straight-toothed configuration.

14. Electric motor according to one of the preceding claims, characterized in that the respective recess has a radial width that decreases monotonically with increasing circumferential angle at its circumferentially arranged end region and a radial width that decreases monotonically with decreasing circumferential angle at its other end region.

15. Electric motor according to one of the preceding claims, characterized in that the respective end cap is flush with the respective tooth neck, but projects radially outwards in the radial direction on the tooth head, in particular wherein the resulting projecting areas are formed as centering ribs (30) and also project in the axial direction, in particular wherein they bear against the stator lamination stack, in particular on the radially outer side of the tooth heads, in particular bearing against it with axial preload.

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