Electric motor
The electric motor's innovative design with a projecting collar area and external bearings and seals prevents explosion fronts from propagating internally, enhancing safety and explosion protection.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SEW EURODRIVE GMBH & CO KG
- Filing Date
- 2025-11-13
- Publication Date
- 2026-07-02
AI Technical Summary
Existing electric motors lack effective measures to prevent the propagation of explosion fronts within their internal components, posing a safety risk.
The electric motor design incorporates a stator housing with a collar area that projects into the interior, creating a gap between the rotor shaft and the collar area to contain explosion fronts, with a shaft seal and additional bearings positioned outside the explosion-proof area to enhance safety.
The design effectively prevents the propagation of explosion fronts, ensuring improved safety and explosion protection by containing the explosion within the motor's exterior components.
Smart Images
Figure EP2025082967_02072026_PF_FP_ABST
Abstract
Description
[0001] electric motor
[0002] Description:
[0003] The invention relates to an electric motor.
[0004] It is generally known that an electric motor has a rotatably mounted rotor shaft.
[0005] From DE 102009013049 B4, an electric motor is known as the closest prior art.
[0006] The invention is therefore based on the objective of further developing an electric motor, with the aim of achieving increased safety.
[0007] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1.
[0008] Important features of the invention in the electric motor are that the electric motor
[0009] a stator housing
[0010] a stator winding surrounded in particular radially by the stator housing,
[0011] a rotatably mounted rotor shaft and
[0012] a flange part
[0013] features, wherein the rotor shaft protrudes through a continuous recess in the stator housing,
[0014] wherein a collar area is formed on the stator housing, which projects axially into the interior area surrounded by the stator housing, in particular of the electric motor,
[0015] in particular wherein the collar area is ring-shaped and the rotor shaft extends through the ring opening of the collar area.
[0016] ISI \ EIDOPAT 13.11.2025 It is advantageous that the rotor shaft is supported outside the interior area. Thus, the bearing is located outside the explosion-proof interior area. For this purpose, the collar area is designed to project inwards, allowing for a suitably dimensioned gap between the collar area and the rotor shaft to be formed, preventing the propagation of an explosion front, in particular an explosion front penetrating the gap from the interior area.
[0017] In an advantageous embodiment, a hollow cylindrical air gap or clear gap is formed between the collar area and the rotor shaft, in particular wherein the gap prevents the propagation of an explosion front. It is advantageous that the gap is sufficiently long and narrow to prevent the propagation of the explosion front.
[0018] In an advantageous embodiment, the stator housing is formed continuously and / or in one piece in the area covered by the collar region in the axial direction, radially outside the collar region and / or radially outside the radial inner surface of the collar region. It is advantageous that the collar region is located inside the stator housing and the bearing is located outside the stator housing.
[0019] In an advantageous embodiment, a flange part is connected to the stator housing, through which the rotor shaft protrudes. It is advantageous that this flange part is arranged outside the stator housing.
[0020] In an advantageous embodiment, the axially measured length of the radial inner side of the collar region or of the gap arranged between the stator housing including the collar region and the rotor shaft is greater than the axially measured length of the bearing. The advantage here is that a sufficiently large axial length is available to prevent the propagation of an explosion front.
[0021] In an advantageous embodiment, the collar area around the recess of the stator housing is formed completely circumferentially, i.e., uninterrupted. An advantage of this is that improved explosion protection can be achieved.
[0022] In an advantageous embodiment, the collar area around the rotor shaft is completely circumferential, i.e., continuous. An advantage of this is that improved explosion protection can be achieved. In another advantageous embodiment, a shaft seal is arranged on the side of the bearing facing away from the gap in the axial direction. This seal, together with the bearing, is received in a projection extending from the stator housing in the opposite direction to the axial direction. An advantage of this is that the bearing and the shaft seal can be received from the surrounding environment at the stator housing.
[0023] In an advantageous embodiment, the extension projects from the stator housing on the side facing away from the gap. It is advantageous that the bearing and the shaft seal are located outside the explosion-proof area. In particular, this prevents heat buildup in the area of the bearing or the shaft seal.
[0024] In an advantageous embodiment, the shaft seal ring seals towards the rotor shaft,
[0025] In particular, a sealing lip of the shaft seal contacts the rotor shaft. An advantage here is that the sealing function is performed outside the interior.
[0026] In an advantageous embodiment, the area covered axially by the stator winding of the electric motor overlaps with the area covered axially by the collar area. It is advantageous that the stator winding overlaps the collar area axially. Thus, the collar area projects sufficiently deep into the interior to achieve this axial overlap. The stator winding and the collar area are radially spaced apart.
[0027] In an advantageous embodiment, the area covered axially by the stator winding of the electric motor overlaps with the area covered axially by the gap, which is particularly hollow cylindrical. It is advantageous that the stator winding overlaps the gap axially. Thus, the collar area projects so deeply into the interior that axial overlap occurs. The stator winding and the gap are radially spaced apart.
[0028] In an advantageous embodiment, the area covered radially by the stator winding of the electric motor is, in particular, completely encompassed, and especially truly encompassed, by the area covered radially by the stator housing. It is advantageous that the stator housing radially surrounds the stator winding and is closed on the A-side.
[0029] In an advantageous embodiment, a further bearing for the rotatable mounting of the rotor shaft is accommodated in a bearing flange. This flange is connected to the stator housing on the side of the stator housing facing away from the flange section and closes the stator housing, in particular so that the stator winding is enclosed by the stator housing together with the bearing flange. It is advantageous that the second bearing can also be arranged outside the interior area and that a collar area projecting into the interior area is also formed on the bearing flange. Between this collar area and the rotor shaft, a gap, in particular a hollow cylindrical one, can also be formed to prevent the propagation of an explosion front within the gap.
[0030] In an advantageous embodiment, the flange part is arranged radially outside the collar area. It is advantageous that the flange part projects on the outside of the stator housing and the collar area projects on the inside of the stator housing.
[0031] In a preferred design, the stator housing and the flange are each made of steel. An advantage of this design is that an explosion-proof version of the motor can be easily implemented.
[0032] 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 schematic illustrations:
[0033] Figure 1 shows a sectional view of the output side area, in particular the A-side, of an electric motor according to the invention.
[0034] As shown in Figure 1, the electric motor has a stator housing 1 which surrounds a stator winding 2 and which accommodates a bearing 4, in particular a rolling bearing, by means of which a rotor shaft of the electric motor is rotatably mounted.
[0035] The axial direction is always aligned parallel to the axis of rotation of the rotor shaft 7. The radial direction is also relative to the axis of rotation of the rotor shaft 7, and the circumferential direction is likewise relative to the axis of rotation of the rotor shaft 7.
[0036] The stator housing 1 is designed in a pot shape on its output side, with the rotor shaft 7 protruding through a recess in the pot base of the stator housing.
[0037] A collar area 3 is formed on the stator housing 1, projecting into the interior area enclosed by the stator housing 1, and is formed around the recess and / or the rotor shaft 7.
[0038] Between the rotor shaft 7 and the collar area 3, a hollow cylindrically shaped, in particular very narrow, air gap is formed, which acts as a spark-proof gap, so that the electric motor is designed as a pressure-resistant encapsulated motor.
[0039] The axial length of the air gap preferably exceeds the axial length of the bearing 4.
[0040] The collar area 3 is arranged radially inside the stator winding 2 of the electric motor.
[0041] The area covered by the collar region 3 in the axial direction overlaps with the area covered by the stator winding 2. Thus, the collar region 3 projects into the area covered by the stator winding 2. The bearing receiving area, in particular the bearing seat, formed on the stator housing 1 is located on the side of the air gap facing away from the interior in the axial direction. In particular, the bearing 4 is separated from the interior by the air gap.
[0042] A shaft seal 5 is arranged on the side of the bearing 4 facing axially away from the air gap. The shaft seal 5 is received in the stator housing 1. For this purpose and for receiving the bearing 4, a corresponding extension is formed on the stator housing 1, which is directed opposite to the collar region 3, and thus projects into the surrounding area. The axial length of the extension exceeds the axial length of the collar region. The extension is arranged radially outside the collar region 3 with respect to the axis of rotation of the rotor shaft 7.
[0043] A flange part 6 is mounted on the outside of the stator housing 1, so that the rotor shaft 7 protrudes through the flange part 6. Since the flange part 6 is only secured to the stator housing 1 by screws inserted into threaded holes in the stator housing part, it can be replaced quickly and easily without altering or affecting the explosion protection of the motor. This is because, due to the cup-shaped design of the stator housing 1, no explosion-proof ignition gap is necessary between the flange part 6 and the stator housing 1. Such an air gap exists only between the rotor shaft 7 and the collar area 3 of the stator housing 1.
[0044] On the side of the stator housing 1 facing axially away from the flange part 6, a bearing shield is connected to the stator housing 1. In particular, the bearing shield covers the pot opening of the pot-shaped stator housing 1 and / or functions as a pot lid for the pot-shaped stator housing.
[0045] The bearing shield incorporates a second bearing for the rotatable mounting of the rotor shaft 7.
[0046] In further embodiments according to the invention, instead of an air gap, a gap at least partially filled with oil and / or grease is used.
[0047] In further embodiments according to the invention, the collar region 3 has a special axial wall thickness profile, which leads to an increased stiffness of the collar region 3 and thus guarantees the air gap, particularly in the event of an explosion. In particular, the radial wall thickness of the collar region 3 with increasing axial distance from the bearing 4 is a strictly monotonically decreasing function of this distance.
[0048] In particular, the function is composed of a hyperbolic function, especially a hyperbolic function, valid in a first axial region, and a root function valid in a second region.
[0049] The hyperbolic function transitions smoothly, i.e., continuously and differently, into the square root function, and the second axial region borders directly on the first region.
[0050] On the front side of the collar area 3, the square root function reaches a vanishing value.
[0051] Preferably, the hyperbolic function is proportional to 1 / (x - a), where a is a constant value and x is the distance to the bearing, and where the square root function is proportional to
[0052] ( b - x ) A 1 is, where b is another constant value,
[0053] in particular wherein the radial direction is relative to the axis of rotation of the rotor shaft and wherein the axial direction is aligned parallel to the axis of rotation of the rotor shaft,
[0054] in particular where b denotes the axial distance of the stator side of the collar area 3 to the bearing and a denotes the wall thickness of the stator housing on the side of the stator housing facing the bearing 4.
[0055] The transition from the hyperbolic function to the square root function significantly increases the stiffness of the collar area, especially in contrast to a function composed of circular arcs and straight lines, which would result in lower fracture resistance. (List of reference symbols)
[0056] 1 Stator housing
[0057] 2 Stator winding
[0058] 3 Collar area
[0059] 4 bearings
[0060] 5 shaft seal
[0061] 6 Flange part
[0062] 7 Rotor shaft
Claims
Patent claims:
1. Electric motor, exhibiting a stator housing a stator winding surrounded in particular radially by the stator housing, a rotatably mounted rotor shaft and a flange part characterized by the fact that the rotor shaft protrudes through a continuous recess in the stator housing, wherein a collar area is formed on the stator housing, which projects axially into the interior area surrounded by the stator housing, in particular of the electric motor, 2. Electric motor according to claim 1, in particular wherein the collar area is annular and the rotor shaft projects through the annular opening of the collar area. characterized by the fact that a hollow cylindrical air gap or clear gap is formed between the collar area and the rotor shaft, in particular wherein the gap prevents the propagation of an explosion front.
3. Electric motor according to any of the preceding claims, characterized by the fact that the stator housing is designed to be continuous and / or in one piece in the area covered by the collar area in the axial direction radially outside the collar area and / or radially outside the radial inside of the collar area.
4. Electric motor according to any of the preceding claims, characterized by the fact that A flange part is connected to the stator housing, through which the rotor shaft protrudes.
5. Electric motor according to any of the preceding claims, characterized by the fact that the axially measured length of the radial inside of the collar area or of the gap arranged between the stator housing including the collar area and the rotor shaft is greater than the axially measured length of the bearing.
6. Electric motor according to any of the preceding claims, characterized by the fact that the collar area around the recess of the stator housing is formed completely circumferentially, in particular without interruption, and / or that The collar area around the rotor shaft is formed completely circumferentially, in particular without interruption.
7. Electric motor according to one of the preceding claims, characterized by the fact that A shaft seal ring is arranged on the side of the bearing facing away from the gap in the axial direction, which, together with the bearing, is received in a projection on the stator housing that extends in the opposite direction to the axial direction.
8. Electric motor according to any of the preceding claims, characterized by the fact that the extension protrudes from the stator housing towards the side facing away from the gap.
9. Electric motor according to any of the preceding claims, characterized by the fact that the shaft seal seals towards the rotor shaft, in particular where a sealing lip of the shaft seal touches the rotor shaft.
10. Electric motor according to any of the preceding claims, characterized by the fact that The area covered by the stator winding of the electric motor in the axial direction overlaps with the area covered by the collar area in the axial direction.
11. Electric motor according to any of the preceding claims, characterized by the fact that The area covered by the stator winding of the electric motor in the axial direction overlaps with the area covered by the gap, in particular the hollow cylindrical gap, in the axial direction.
12. Electric motor according to any of the preceding claims, characterized by the fact that The area covered by the stator winding of the electric motor in the radial direction is in particular completely encompassed by the area covered by the stator housing in the radial direction, and in particular truly encompassed.
13. Electric motor according to one of the preceding claims, characterized by the fact that A further bearing for the rotatable mounting of the rotor shaft is received in a bearing flange, which is connected to the stator housing on the side of the stator housing facing axially away from the flange part and which closes the stator housing, in particular so that the stator winding is enclosed by the stator housing together with the bearing flange.
14. Electric motor according to any of the preceding claims, characterized by the fact that the flange part is arranged radially outside the collar area, and / or that The stator housing and the flange part are each made of steel.
15. Electric motor according to any of the preceding claims, characterized by the fact that the collar area protrudes axially into the interior area surrounded by the stator housing, in particular of the electric motor, on the side of the stator housing facing away from the bearing. and / or that The radial wall thickness of the collar area with increasing axial distance from the bearing is a strictly monotonically decreasing function of this distance. in particular wherein the function is composed of a hyperbolic function in a first axial region, in particular a hyperbolic function, and of a square root function valid in a second region, wherein the hyperbolic function smoothly, in particular continuously and differentiably, transitions into the square root function and wherein the second axial region adjoins the first region, in particular wherein the hyperbolic function is proportional to 1 / (x - a) where a is a constant value and x is the distance to the bearing, and wherein the square root function is proportional to ( b - x ) A 1 is, where b is another constant value, in particular wherein the radial direction is relative to the axis of rotation of the rotor shaft and wherein the axial direction is aligned parallel to the axis of rotation of the rotor shaft, in particular where b denotes the axial distance of the stator side of the collar area to the bearing and a denotes the wall thickness of the stator housing on the side of the stator housing facing the bearing.