Electric motor having a fan and a stator housing part, a first end shield and a second end shield

Abstract

The invention relates to an electric motor comprising a stator housing part, a first end shield and a second end shield, wherein the stator housing part is arranged between the first end shield and the second end shield, wherein a fan is arranged on the electric motor, wherein the air flow conveyed by the fan is directed at least towards a deflection pocket of the first end shield formed on the stator housing part and towards a passage passing through an outer wall region of the stator housing part, wherein the stator housing part has axially continuous first channels and axially continuous second channels, wherein a portion of the air flow conveyed by the fan, in particular in the radial direction, bypasses the deflection pocket and is supplied to the second channels, such that, after flowing through the second channels, said portion exits the second channels into the ambient air, wherein the portion of the air flow conveyed by the fan and conveyed through the passage is supplied to the first channels and flows into the interior region of the electric motor surrounded by the second end shield and then at least partially flows back through an annular gap between the stator lamination stack accommodated in the stator housing part and the rotor rotatably mounted via bearings accommodated in the end shields into the interior region of the electric motor surrounded by the first end shield.

Description

[0001] Electric motor with a fan and a stator housing part, a first bearing shield and a second bearing shield

[0002] Description:

[0003] The invention relates to an electric motor with a fan and a stator housing part, a first bearing shield and a second bearing shield.

[0004] It is generally known that the waste heat from an electric motor must be dissipated to the environment, for example by means of water cooling.

[0005] According to US 2004 / 0 150270 A1, the closest state of the art is a motor with a fan.

[0006] An air-cooled electric machine is known from EP 2 086 091 A2.

[0007] The invention is therefore based on the objective of further developing an electric motor, whereby improved heat dissipation should be achievable.

[0008] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1.

[0009] Key features of the invention for the electric motor comprising a stator housing part, a first bearing shield, and a second bearing shield are that the stator housing part is arranged between the first bearing shield and the second bearing shield, a fan is arranged on the electric motor, the airflow conveyed by the fan being directed at least towards a deflection pocket formed on the stator housing part of the first bearing shield and towards a passage, in particular a recess, through an outer wall region of the stator housing part, in particular radially, the stator housing part having axially extending first channels and axially extending second channels, the deflection pocket deflecting a portion of the airflow conveyed by the fan, in particular in a radial direction, into the axial direction and directing it to the second channels, so that this portion exits the second channels into the ambient air after passing through them.wherein the portion of the airflow conveyed by the fan, conveyed through the passage, is fed to the first channels and flows into the interior of the electric motor surrounded by the second bearing shield, and then flows back, at least partially, through an annular gap between the stator lamination stack housed in the stator housing part and the rotor rotatably mounted on bearings, in particular rolling bearings, housed in the bearing shields, into the interior of the electric motor surrounded by the first bearing shield.

[0010] An advantage of this design is the inclusion of recesses in the stator housing section, which act as deflection pockets, directing a portion of the airflow along the outer surface of the stator housing section through the secondary channels. The remaining portion of the airflow is routed through the interior, particularly through the primary channels. This design cools the stator housing section with an external airflow, which also passes through the housing section. Simultaneously, it creates air circulation within the interior, dissipating heat across the entire interior surface. Since the secondary channels have a larger cross-sectional area than the primary channels, heat dissipation to the environment is more efficient. However, heat dissipation within the interior is less efficient than heat transfer to the environment.

[0011] In an advantageous embodiment, the first and second channels are located in corner regions of the stator housing section and are radially spaced further apart than the smallest outer radius of the stator housing section. It is advantageous that the cuboid outer contour and the incorporated cylindrical stator lamination stack create radially projecting corner regions, particularly axial edge regions, in which the channels can be accommodated without requiring additional space.In an advantageous embodiment, the stator lamination stack is received in a cylindrical recess of the stator housing part, wherein the stator housing part has a cuboid outer circumference, in particular wherein the smallest outer radial distance of the stator housing part is larger than the outer radius of the stator lamination stack, and in particular exceeds it by the minimum wall thickness of the stator housing part, in particular wherein the first channels and the second channels are arranged in the four corner regions of the cross-section of the stator housing part whose cross-sectional area has a normal direction that is aligned parallel to the axial direction. It is advantageous that the cuboid outer contour and the received cylindrical stator lamination stack create the radially projecting corner regions, in particular axial edge regions, in which the channels can be received without requiring additional space.

[0012] In an advantageous embodiment, the first channels are arranged circumferentially between the second channels. It is advantageous that the heat spreading in the circumferential direction takes place within the second channels.

[0013] In an advantageous embodiment, at least a second channel has a triangular cross-section, and the extent of the respective triangle, in particular the triangular cross-section, is larger in the circumferential direction than in the radial direction. The advantage here is that the corner areas can be used optimally.

[0014] In an advantageous embodiment, the first and second channels, which are designed as round bores, are arranged circumferentially between the second channels, which have a triangular cross-section. The advantage here is that the corner areas can be optimally utilized.

[0015] In an advantageous embodiment, the portion of the airflow deflected by the deflecting pocket is separated from the space enclosed by the first bearing shield by means of one side of the deflecting pocket wall. It is advantageous that the two portions of the airflow are guided separately. In an advantageous embodiment, at least one further continuous recess in the outer wall area of ​​the stator housing part, in particular a radially continuous passage, is covered by an inspection window, wherein the inspection window has continuous grille openings, in particular slots, through which a portion of the airflow from the interior area escapes into the ambient air, and wherein the inspection window is fastened to the stator housing part by means of screws. It is advantageous that the portion of the airflow can escape without a human finger being able to enter the interior area.

[0016] In a preferred design, the inspection window is manufactured as an injection-molded plastic part. This offers the advantage of cost-effective production, especially despite complex geometries. For example, a sloping roof to protect against rain can be incorporated at each grille opening.

[0017] In a preferred embodiment, the stator housing part is a machined metal casting. An advantage of this design is that the stator can be made robust.

[0018] In an advantageous embodiment, the total cross-sectional area of ​​the first channels is smaller than the total cross-sectional area of ​​the second channels, in particular that the total cross-sectional area of ​​the first channels is smaller than the total cross-sectional area of ​​the second channels. It is advantageous that the heat dissipation can be implemented efficiently, in particular more efficiently than heat spreading.

[0019] In an advantageous embodiment, the radial spacing area covered by the first and second channels overlaps with or is contained within the radial spacing area covered by the inspection window. An advantage of this is that the motor can be designed compactly by spacing the first and second channels circumferentially from the inspection window, particularly with respect to the axis of rotation of the rotor shaft. In an advantageous embodiment, the inspection window has a respective inclined canopy section at the edge of each grille opening, in particular each slot, wherein the angles of inclination of all canopy sections are parallel to each other and / or wherein the respective angle of inclination of the respective canopy section is less than 90°.The advantage here is that simple manufacturing is possible and, on the one hand, the outgoing airflow flows at least partially along the inspection window and, on the other hand, water flowing down can be prevented from passing through the grille openings.

[0020] In an advantageous embodiment, each canopy section is inclined towards the respective slot it at least partially borders. This is advantageous because, on the one hand, the outgoing airflow flows at least partially along the inspection window, and on the other hand, water flowing down the grille openings can be prevented from doing so.

[0021] In an advantageous embodiment, the airflow, after exiting the inspection window, flows at least partially along the inspection window. An advantage of this is that

[0022] In a preferred design, the canopy sections project at least partially beyond the grille openings towards the surrounding area. An advantage of this is that water flowing down the inspection window is kept away from the grille openings. In particular, the water runs off the inspection window without penetrating through the grille openings.

[0023] In an advantageous embodiment, the inspection window, including its canopy sections, is manufactured as a single piece, particularly in one piece. This offers the advantage of cost-effective production.

[0024] Further advantages arise from the dependent claims. The invention is not limited to the combination of features in 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, particularly 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.

[0025] Figure 1 shows a first bearing shield 3 of an electric motor according to the invention in oblique view.

[0026] Figure 2 shows a stator housing of the electric motor in an oblique view.

[0027] Figure 3 shows a second bearing shield 30 of the electric motor in oblique view.

[0028] Figure 4 shows one of the inspection windows 40 of the electric motor in oblique view.

[0029] As shown in the figures, the electric motor has a stator, wherein a stator housing part 20 of the stator is arranged axially between the first bearing shield 3 and the second bearing shield 30. Within the stator housing part 20 is a stator lamination stack 23, which consists of individual laminations stacked in the axial direction.

[0030] Each of the two bearing shields (3, 30) contains a bearing by which a rotor shaft, not shown in the figures, is rotatably mounted.

[0031] A stator winding, in particular a three-phase winding, is accommodated in the stator lamination stack 23, in particular in the axially extending slots of the stator lamination stack.

[0032] Preferably, the two bearing shields (3, 30) are pressed onto the stator housing part 20 by means of long screws.

[0033] The two bearing shields (3, 30) together with the stator housing part 20 form a housing of the electric motor, with a fan mounted on the housing.

[0034] The airflow conveyed by the fan is directed towards a first, in particular radial, passage 1 of the first bearing shield 3 and towards deflection pocket 2 of the first bearing shield 3. The first passage 1 is a recess in the outer wall of the first bearing shield 1 and thus allows the conveyed airflow to flow into the interior of the electric motor enclosed by the housing.

[0035] Since the stator housing part 20 has axially continuous first channels 21, the airflow entering through the first opening 1 flows through these first channels 21, which open into the interior space surrounded by the second bearing shield 30. From there, the airflow can flow back to the interior space enclosed by the first bearing shield 3 through the annular gap between the stator lamination stack 23 and the rotor arranged radially within the stator lamination stack 23.

[0036] The second bearing shield 30 has further recesses which are covered by an inspection window 40 having grille openings 41, in particular slots. Thus, part of the conveyed airflow flows through these grille openings 41 into the external environment.

[0037] The inspection window 40 has a corresponding inclined canopy section at the edge of each grille opening 41. The angles of inclination of all canopy sections are parallel to each other, and each angle of inclination is less than 90°, meaning that each canopy section is inclined towards the respective slot. Thus, after exiting the inspection window 40, the airflow flows at least partially along the inspection window 40. Since the canopy sections project at least partially beyond the grille openings 41 towards the surrounding area, visual inspection through the inspection window 40 is made more difficult by the canopy sections.

[0038] The inspection window, including its canopy section, is manufactured as a single piece, in particular as a single unit. Therefore, for inspection purposes, the inspection window 40 is preferably removed.

[0039] The deflection pocket 2 formed on the first bearing shield 3 deflects the radially flowing air outside the interior enclosed by the first bearing shield 3 in an axial direction, so that it encounters second channels 22, which are incorporated into the stator housing part 20 and extend axially through the stator housing part 20. The airflow exiting the channels 22 is deflected radially by corresponding deflection pockets 2 formed on the second bearing shield 30 and thus enters the ambient air. An important aspect of the invention is that the first and second channels (21, 23) are each arranged in corner regions of the stator housing part 20. These corner regions are provided by the fact that the stator lamination stack is received in an inner cylindrical recess of the stator housing part 20 and the outer contour of the stator housing part 20 is essentially cuboid.

[0040] The stator housing part 20 has a radially directed minimum wall thickness on its outer sides, which is exceeded in the corner areas because the cuboid accommodates the inner cylinder and thus the corner areas project radially beyond the inner cylinder, taking into account the minimum wall thickness.

[0041] Preferably, two deflection pockets are arranged in each of the four corner areas, with the respective first channels 21 arranged in the circumferential direction between the two deflection pockets.

[0042] The first channels 21 are designed as circular bores. The second channels 22 are also designed as circular bores, with the addition of further channels 22 with a triangular cross-section.

[0043] Particularly preferred are all first and second channels (21, 22) designed as round bores arranged circumferentially between the second channels designed with a triangular cross-section in each corner area.

[0044] Preferably, the triangular cross-section of the channels 22 is oriented such that the circumferential dimension of each triangle is longer than the radial dimension. This allows for particularly efficient use of the available space in the respective corner area.

[0045] The axial direction is aligned parallel to the rotor's axis of rotation. The circumferential direction is also relative to the rotor's axis of rotation. The radial direction is also relative to the rotor's axis of rotation. In further embodiments of the invention, the first and second channels (21, 22) are provided in the stator lamination stack 23 instead of, or in addition to, the stator housing part 20. For this purpose, the minimum radial wall thickness of the stator lamination stack 23 is increased accordingly.

[0046] Reference symbol list

[0047] 1 First radial passage 2 Deflection pocket

[0048] 3 first warehouse sign

[0049] 20 Stator housing part

[0050] 21 first channels

[0051] 22 second channels 23 stator lamination stack

[0052] 30 second warehouse sign

[0053] 40 inspection windows

[0054] 41 Grille openings, especially slots

Claims

Patent claims:

1. Electric motor with a fan and a stator housing part, a first bearing shield and a second bearing shield, wherein the stator housing part is arranged between the first bearing shield and the second bearing shield, wherein the fan is arranged on the electric motor, in particular on the housing of the electric motor, characterized in that the airflow conveyed by the fan is directed at least towards a deflection pocket formed on the stator housing part of the first bearing shield and towards a passage, in particular a recess, through an outer wall area of ​​the stator housing part, in particular radially, wherein the stator housing part has axially extending first channels and axially extending second channels, wherein the deflection pocket deflects a portion of the airflow conveyed by the fan, in particular in a radial direction, in the axial direction and feeds it to the second channels.so that this portion, after passing through the second channels, exits the second channels into the ambient air, wherein the portion of the airflow conveyed by the fan, conveyed through the passage, is fed to the first channels and flows into the interior area of ​​the electric motor surrounded by the second bearing shield, and then flows back, at least partially, through an annular gap between the stator lamination stack received in the stator housing part and the rotor rotatably mounted on bearings, in particular rolling bearings, received in the bearing shields, into the interior area of ​​the electric motor surrounded by the first bearing shield.

2. Electric motor according to claim 1, characterized in that the first channels and the second channels are placed in corner regions of the stator housing part and are spaced radially further apart than the smallest outer radius of the stator housing part.

3. Electric motor according to one of the preceding claims, characterized in that the stator lamination stack is received in a cylindrical recess of the stator housing part, wherein the stator housing part has a cuboid outer circumference, in particular wherein the smallest outer radial distance of the stator housing part is greater than the outer radius of the stator lamination stack, in particular and exceeds it by the minimum wall thickness of the stator housing part, in particular wherein the first channels and the second channels are arranged in the, in particular, four corner regions of that cross-section of the stator housing part whose cross-sectional area has a normal direction which is aligned parallel to the axial direction.

4. Electric motor according to one of the preceding claims, characterized in that the first channels are arranged in the circumferential direction between the second channels.

5. Electric motor according to one of the preceding claims, characterized in that at least a second channel has a triangular cross-section and the extent of the respective triangle, in particular the triangular cross-section, is greater in the circumferential direction than in the radial direction.

6. Electric motor according to one of the preceding claims, characterized in that the first and second channels, which are designed as round bores, are arranged circumferentially between the second channels, which have a triangular cross-section.

7. Electric motor according to one of the preceding claims, characterized in that the portion of the airflow deflected by the deflecting pocket is separated from the area enclosed by the first bearing shield by means of one side of the pocket wall of the deflecting pocket.

8. Electric motor according to one of the preceding claims, characterized in that at least one further continuous recess of the outer wall area of ​​the stator housing part, in particular a radially continuous passage, in particular recess, is covered by means of an inspection window, wherein the inspection window has continuous grille openings, in particular slots, in particular through which an airflow component from the interior area exits into the ambient air, in particular wherein the inspection window is fastened to the stator housing part by means of screws.

9. Electric motor according to one of the preceding claims, characterized in that the radial spacing area covered by the first and second channels overlaps with or is contained in the radial spacing area covered by the inspection window.

10. Electric motor according to one of the preceding claims, characterized in that the inspection window is manufactured as a plastic injection molded part, and / or that the stator housing part is a machined metal casting part.

11. Electric motor according to one of the preceding claims, characterized in that the total cross-section of the first channels is smaller than the total cross-section of the second channels, in particular that the total cross-section of the first channels is smaller than the total cross-section of the second channels.

12. Electric motor according to one of the preceding claims, characterized in that the inspection window at the edge of each grille opening, in particular each slot, has a respective inclined canopy section, in particular wherein the inclination angles of all canopy sections are aligned parallel to each other and / or wherein the respective inclination angle of the respective canopy section is less than 90°.

13. Electric motor according to one of the preceding claims, characterized in that the respective canopy section is inclined towards the respective slot which it at least partially borders.

14. Electric motor according to one of the preceding claims, characterized in that the airflow, after exiting the inspection window, flows at least partially along the inspection window.

15. Electric motor according to one of the preceding claims, characterized in that the canopy sections extend at least partially beyond the grille openings towards the surroundings, and / or that the inspection window together with its canopy sections is made in one piece, in particular in one piece.

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