Fan hood for an electric motor with fan and electric motor with fan hood

Abstract

Fan cover for an electric motor with fan wherein the fan hood has a circular cylindrical section and a polygonal section, the polygonal section having discrete rotational symmetry about the cylinder axis, wherein the area axially covered by the circular cylindrical section is spaced apart from or adjacent to the area axially covered by the polygonal section, wherein a housing part of the electric motor can be connected to a polygonal section of the fan hood, wherein the fan hood has a fan hood grille at its axial end region facing away from the polygonal section for the inlet of a cooling airflow, the fan hood is manufactured as a deep-drawn part, characterized by the fact that at least one supporting rib is formed on the circular cylindrical section, wherein the axial area covered by the support rib at least overlaps with the axial area covered by the circular cylindrical section, wherein the circumferential width of each support rib increases monotonically or even strictly monotonically with increasing distance in the axial direction from the fan hood grid, wherein in the circumferential angle range covered by the support rib, the radial spacing range covered by the support rib covers that radial spacing range which extends between the radial spacing of the circular cylindrical section and the radial spacing of the polygonal section.

Description

[0001] The invention relates to a fan hood for an electric motor with a fan and an electric motor with a fan hood.

[0002] It is generally known that electric motors have fans for cooling.

[0003] From WO 2008 / 061 943 A1, an electric motor with quick-release fan unit is known.

[0004] From DE 10 2011 078 742 A1 an electric machine with an external fan is known.

[0005] An electric motor is known from DE 10 2010 024 302 A1.

[0006] The invention is therefore based on the objective of designing a fan hood with low noise emission, in particular low vibration tendency.

[0007] According to the invention, the problem is solved in the case of the fan hood according to the features specified in claim 1 and in the case of the electric motor according to the features specified in claim 12.

[0008] Important features of the invention for the fan housing for an electric motor with fan are that the fan housing has a circular cylindrical section and a polygonal section, wherein the polygonal section has a discrete rotational symmetry about the cylinder axis,

[0009] wherein the area axially covered by the circular cylindrical section is objected to, the area axially covered by or adjacent to the polygonal section, in particular wherein a housing part of the electric motor can be connected to a polygonal section of the fan hood and / or wherein the fan hood has a fan hood grille at its axial end region facing away from the polygonal section for the inlet of an airflow, in particular a cooling airflow.

[0010] A key advantage is that a square or polygonal electric motor can be connected, and the fan housing is attached without significant gaps. This results in only negligible cooling airflow losses. In the area of ​​the fan, which is driven by the motor's rotor shaft and preferably rigidly connected to the rotor shaft, the cooling airflow is only slightly turbulent and therefore as laminar as possible. The robust sheet metal construction and deep-drawn design ensure high stability of the fan housing and thus lower noise emissions, even when vibrations from the motor are introduced into the housing.

[0011] In an advantageous embodiment, the fan hood is manufactured as a deep-drawn part, in particular a sheet metal part, especially made of sheet steel or aluminum sheet. In particular, the wall thickness of the fan hood remains essentially constant. An advantage of this design is that it allows for low noise emissions.

[0012] According to the invention, at least one support rib is formed on the circular cylindrical section, wherein the axial area covered by the support rib at least overlaps with, is identical to, or is contained within the axial area covered by the circular cylindrical section, and in particular is not spaced apart. An advantage of this is that a higher degree of stiffness can be achieved.

[0013] According to the invention, in the circumferential angle region covered by the support rib, the radial spacing region covered by the support rib encompasses the radial spacing region that extends between the radial spacing of the circular cylindrical section and the radial spacing of the polygonal section. An advantage of this is the provision of a stiffness-enhancing transition region that is easy to manufacture. This is because the support rib is hollow, i.e., formed as a bulge in the fan housing, and thus the fan housing can be manufactured as a deep-drawn part.

[0014] In an advantageous embodiment, the support ribs are spaced apart from each other in the circumferential direction, particularly at regular intervals. A key advantage is that high stiffness can be achieved by incorporating steps in the circumferential direction. This allows for a particularly high degree of stiffness.

[0015] In an advantageous embodiment, directly adjacent support ribs in the circumferential direction have different dimensions, particularly widths, in the circumferential direction. It is advantageous that wider support ribs can be provided in the corner areas and narrower support ribs in the other side areas of the square. This ensures good utilization of the installation space, achieving high stiffness with minimal material usage. Furthermore, the fan hood can again be manufactured as a deep-drawn part.

[0016] According to the invention, the circumferential width of each support rib increases monotonically or even strictly monotonically with increasing axial distance from the fan housing grille. An advantage of this is that it can be manufactured as a deep-drawn part.

[0017] In an advantageous embodiment, the polygonal section has a periodically varying axial height, and thus axial extent, in the circumferential direction. This is advantageous because it allows for particularly high stiffness. Furthermore, the mechanical natural vibrations of the fan housing are shifted towards higher frequencies.

[0018] In an advantageous embodiment, the circular cylindrical section has a shoulder, wherein the shoulder has an axial height, and in particular axial extent, that varies periodically in the circumferential direction, wherein the step is arranged radially between the circular cylindrical section and the polygonal section, In particular, the shoulder has a constant radial extent in the circumferential direction. An advantage of this is the further increase in stiffness.

[0019] In an advantageous embodiment, the periodically varying height profile of the heel has a first period length in the circumferential direction, that the periodically varying height profile of the polygonal section has a second period length in the circumferential direction, The first and second periods are equal. This offers the advantage of simple manufacturing and high stiffness, especially with a mutual phase shift of 180°.

[0020] In an advantageous embodiment, the respective height profile has a triangular, sinusoidal, or trapezoidal shape. An advantage of this is that

[0021] In an advantageous embodiment, the periodically varying height profile of the step exhibits a phase difference compared to the periodically varying height profile of the polygonal section. An advantage of this is that particularly high stiffness can be achieved. Especially with a circumferential phase difference of 180° or at least a phase difference between 160° and 200°, very high stiffness can be achieved, since then a maximum of the step's height profile radially opposes a minimum of the polygonal section's height profile, thus maximizing the step change in the radial direction.

[0022] In an advantageous embodiment, the number of periods in the circumferential direction corresponds to an integer or half-integer multiple of the number of vertices of the polygonal segment. An advantage of this is that high stiffness can also be achieved in this way.

[0023] In an advantageous embodiment, the corners of the polygon are rounded, particularly with a continuously connected circular segment. The advantage here is that the rounding can be easily achieved, for example, with an annular segment.

[0024] Key features of the electric motor with fan shroud include the radially oriented screw holes in the motor housing, allowing the fan shroud to be pressed against the housing by the screw head.

[0025] An advantage of this design is the ease of attaching the fan shroud. Furthermore, the semi-circular recesses around the mounting area reduce the transmission of mechanical vibrations from the motor to the fan shroud.

[0026] 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.

[0027] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows a fan hood of an electric motor according to the invention. In the Fig. Figure 2 shows a fan hood with a support rib 20 extending axially along the circular cylindrical section 1 of the fan hood. In the Fig. 3 is a fan hood with axial movement less than in Fig. 2 extending support ribs (30, 31) shown. In the Fig. Figure 4 shows a fan hood with steps that have a periodically varying height profile. Fig. Figure 5 shows a top view of the fan hood and a section line AA. Fig. Figure 6 shows the sectional view of section AA.

[0028] As in Fig. As shown in Figure 1, the fan hood has a square section with which it can be connected to a square housing part, for example, the output-side flange or the bearing shield of the electric motor. The hood is at least partially slid onto the housing part of the electric motor, so that the axial area covered by the square housing part overlaps axially with the area axially covered by the housing part.

[0029] The fan shroud is connected to the housing part by means of screws screwed radially into the housing part, the heads of which press against the rounded corner areas of the square section. The threaded portion of each screw is guided through a recess 5 in the rounded corner area of ​​the square section of the fan shroud.

[0030] A recess 5, spaced apart from the screw connection area, is semi-ring-shaped and thus surrounds the screw connection area in a semi-ring or semi-circular shape. This reduces the coupling of vibrations from the housing part into the fan shroud.

[0031] A circular cylindrical section 1 is connected to the square section, allowing an undisturbed axial flow of the cooling air stream, which enters the fan housing through the grille openings 2 and is driven by a fan radially and axially surrounded by the fan housing. The circular cylindrical shape reduces turbulence and thus also losses.

[0032] The fan hood is made of sheet metal, has essentially the same wall thickness throughout, and is manufactured as a deep-drawn part.

[0033] Thus, the clear diameter corresponding to any circumferential angle increases monotonically from the area of ​​the grid openings 2 in the axial direction towards the motor. This monotonous increase is valid for every circumferential angle. Therefore, there is no undercut.

[0034] Unlike the Fig. 1 shows the fan hood in the exemplary embodiment. Fig. Two support ribs 20 are provided, the axially overlapping area of ​​which overlaps or is identical to the axially overlapping area of ​​the circular cylindrical section 1. Thus, these support ribs 20 extend very far in the axial direction. In the circumferential direction, the support ribs 20 are spaced apart from one another, in particular regularly. There are four support ribs 20.

[0035] Since the wall thickness of the fan hood is essentially constant as a deep-drawn part, the support ribs 20 are manufactured as radially directed protrusions.

[0036] The rigidity of the fan shroud is thus increased. However, the turbulence is also increased by the bulges in the interior in the area of ​​the support ribs 20.

[0037] As in Fig. As shown in Figure 3, axially much fewer support ribs (30, 31) can also be used if their number is increased. In this case, Fig. 3 Eight such support ribs (30, 31) are provided. In the circumferential direction, wider support ribs 30 alternate with narrower support ribs 31.

[0038] The supports (30, 31) are spaced apart in the circumferential direction.

[0039] In the axial direction towards the motor, i.e. moving increasingly away from the grid openings, the width of the supports (30, 31) increases monotonically in the circumferential direction.

[0040] Increased stiffness can also be achieved in this way.

[0041] The fan hood can be manufactured as a single, deep-drawn part. It therefore consists of the circular cylindrical section 1, the support ribs (30, 31) and the polygonal, i.e., square, section, and can be manufactured in one piece.

[0042] As in Fig. 4 shown, but are also effective in stiffening circumferential ridges with a variable height profile.

[0043] In contrast to the previously described embodiments, the square section 3 is designed with a height profile that varies in the axial direction. The axial edge region of the fan housing facing the motor ends at an axial position that is the same for all circumferential angles – except for the recesses 5 for fastening screws.

[0044] The circumferentially varying elevation profile of the square section 3 is periodically variable, with the shape being triangular or sinusoidal. Eight periods are implemented circumferentially. Thus, an outer section 41 with a periodically varying elevation profile is formed.

[0045] The radial width of section 3 is greatest in the rounded corner areas of the square section 3. The radial extent is small in the side areas. A step 40 with a periodically varying height profile is formed between the square section 3 and the circular cylindrical section 1.

[0046] The radial extent of the shoulder 40 is essentially constant, i.e., independent of the circumferential angle. Thus, the radial extent of the shoulder 40 is the same in all circumferential angle directions. However, it also exhibits a periodically varying height profile. The period length, measured in circumferential angles, is preferably the same as the period length of the height profile 41 of the square shoulder 3. More preferably, however, a phase shift or phase difference is present between the height profile 40 and the height profile 41, thus further increasing the stiffness. The phase shift or phase difference is approximately 180°. However, other values ​​between 160° and 200° are also advantageous.

[0047] Thus, the maximum axial height of the shoulder 40 lies essentially in the same or approximately the same circumferential angle range as the minimum height profile 41 of the square section 3.

[0048] Thus, the stiffness can be increased.

[0049] As in Fig. As can be clearly seen in the lower left area of ​​Figure 6, the sectional view shows a stepped rise in the wall of the fan housing towards the motor, i.e., in the axial direction. The steps are very steep, exceeding 88°. Only the edges of these rising steps are rounded, specifically with a circular curve.

[0050] The semi-circular recesses 4 are in the Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Although not shown in Figure 6, it is present in the exemplary embodiment. In conjunction with the aforementioned stiffness-enhancing measures, such as support ribs (20, 30, 31), a significant reduction in noise emission is thus achieved.

[0051] In a further embodiment according to the invention, 2 xn corners are provided on the section facing the motor, where n is an integer greater than 1. The number of periods of the height profile 41 is then preferably mxn, where m is an integer greater than two.

[0052] For n= 2, the exemplary embodiment results according to Fig. 4, which may therefore have a number of 8, 12, 16 etc. periods in the circumferential direction; but in further development it may also have 10, 14, 18 periods in the circumferential direction.

[0053] Instead of a square housing section, a polygonal section is also possible if the housing section of the motor is shaped accordingly.

[0054] The polygon is a regular polygon and thus, like the square section 3, exhibits discrete rotational symmetry about the axial direction, i.e., the cylinder axis.

[0055] The aforementioned embodiments may deviate slightly from the geometric terms used in order to make the manufacturing process easier to implement. Reference symbol list 1 circular cylindrical section 2 grille openings in the fan hood for airflow 3 square section 4 semi-circular recesses 5 Recess for fastening screws 20 support rib 30 wide support rib 31 narrow support ribs 40 paragraphs with periodically varying elevation profiles 41 Height profile of the square section 3, i.e. the radially outer step, with periodically varying height profile

Claims

[1] Fan hood for an electric motor with fan, wherein the fan hood has a circular cylindrical section and a polygonal section, the polygonal section having discrete rotational symmetry about the cylinder axis, wherein the area axially covered by the circular cylindrical section is spaced apart from or adjacent to the area axially covered by the polygonal section, wherein a housing part of the electric motor can be connected to a polygonal section of the fan hood, wherein the fan hood has a fan hood grille at its axial end region facing away from the polygonal section for the inlet of a cooling airflow, the fan hood is manufactured as a deep-drawn part, characterized by , that at least one supporting rib is formed on the circular cylindrical section, wherein the axial area covered by the support rib at least overlaps with the axial area covered by the circular cylindrical section, wherein the circumferential width of each support rib increases monotonically or even strictly monotonically with increasing distance in the axial direction from the fan hood grid, wherein in the circumferential angle range covered by the support rib, the radial spacing range covered by the support rib covers that radial spacing range which extends between the radial spacing of the circular cylindrical section and the radial spacing of the polygonal section. [2] Fan hood according to claim 1, characterized by that the fan hood is manufactured as a sheet metal part, with the wall thickness of the fan hood being essentially constant. [3] Fan hood according to at least one of the preceding claims, characterized by that the support ribs are spaced apart from each other in the circumferential direction. [4] Fan hood according to at least one of the preceding claims, characterized by , that directly adjacent support ribs in the circumferential direction have different extents in the circumferential direction. [5] Fan hood according to at least one of the preceding claims, characterized by , that the polygonal section has an axial height, i.e., axial extent, that varies periodically in the circumferential direction, [6] Fan hood according to at least one of the preceding claims, characterized by , that the circular cylindrical section has a step, wherein the heel has an axial height, i.e. axial extent, that varies periodically in the circumferential direction, the step is arranged radially between the circular cylindrical section and the polygonal section. [7] Fan hood according to claim 6, characterized by , that that the periodically varying axial height profile of the heel has a first period length in the circumferential direction, that the periodically varying axial height profile of the polygonal section has a second period length in the circumferential direction, The first and second periods are the same length. [8] Fan hood according to claim 7, characterized by that the respective axial height profile has a triangular, sinusoidal or trapezoidal shape. [9] Fan hood according to claim 6, 7 or 8, characterized by , that the periodically changing axial height profile of the heel exhibits a phase difference to the periodically changing axial height profile of the polygonal section. [10] Fan hood according to claim 8, 9 or 7, characterized by , that the number of periods in the circumferential direction corresponds to an integer or half-integer multiple of the number of vertices of the polygonal segment. [11] Fan hood according to at least one of the preceding claims, characterized by , that the corners of the polygon are rounded with a continuously connected circular segment. [12] Electric motor with fan hood according to at least one of the preceding claims, characterized by , that in the housing part of the electric motor, a respective screw can be screwed into a threaded hole in a radial direction, so that the fan cover can be pressed against the housing part by the respective screw head.

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