Motors with bypass cooling channels

Abstract

The invention relates to an electric motor (1) having a housing (2), wherein the housing (2) has a hollow cylindrical cooling jacket (2a) for accommodating a stator (3) and a housing closure structure (2b), in particular a bearing cover, arranged on the end side of the cooling jacket (2a), and wherein the cooling jacket (2a) has cooling channels (4a) extending between its end sides (17) and the housing closure structure (2b) has a deflection groove (4b), so that two adjacent cooling channels (4a) are fluidically connected via the deflection groove (4b), so that the cooling channels (4a) and the stator (3) are fluidically connected. The groove (4b) forms a continuous meandering cooling path (10) extending between an inlet (5) and an outlet (6) through the housing (2), through which a cooling medium can flow, wherein the housing (2) has a bypass channel (7) which fluidically connects the inlet (5) and the outlet (6) when bypassing the meandering cooling path (10) or which fluidically connects two partial regions of the meandering cooling path (10) when bypassing a part of the meandering cooling path (10).

Description

Technical Field

[0001] The present invention relates to an electric machine, which in particular has a cooling path passing through its housing, wherein a bypass channel leading to the cooling path is provided. Background Art

[0002] Some electric motors are known from the prior art. As the power of electric motors increases, cooling mechanisms must be provided. For this purpose, a meandering cooling medium path is usually formed through the housing of the electric motor. DE 10 2012 215 018 A1 shows such an electric motor, for example. Summary of the Invention

[0003] The electric machine according to the invention allows for flexible adjustment of the parameters heat transfer and pressure loss. Thus, despite the use of axially centered profiles, cooling jackets, the possibilities for influencing the heat transfer characteristics and the cooling pressure drop are increased compared to the prior art.

[0004] The electric motor according to the present invention comprises a housing. The housing in turn comprises a hollow cylindrical cooling jacket and a housing enclosure structure attached to the cooling jacket at the end. The housing enclosure structure is particularly a bearing cover. The cooling jacket is used to accommodate the stator of the electric motor. The stator of the electric motor can therefore be cooled by the cooling jacket. The cooling jacket has cooling channels that extend between the end sides of the cooling jacket. The housing enclosure structure further comprises a deflection groove. The deflection groove and the cooling channels are fluidically connected to one another such that two adjacent cooling channels are fluidically connected to one deflection groove. In this way, the cooling channels and the deflection groove form a continuous cooling path. The cooling path extends through the housing between an inlet and an outlet. In particular, it is provided that the cooling path extends through the housing in a meandering manner. A cooling medium can flow along the cooling path and thereby cool the housing and, in particular, the stator of the electric motor.

[0005] Advantageously, the housing includes a bypass channel. The inlet and outlet are fluidically connected via the bypass channel while bypassing the meandering cooling path. Consequently, a portion of the cooling medium supplied to the inlet can reach the outlet directly via the bypass channel. This can reduce parameters such as the pressure drop between the inlet and outlet. Alternatively, the bypass channel can also fluidically connect two subregions of the meandering cooling path, wherein only a portion of the meandering cooling path is bypassed. The basic function of the bypass channel remains the same as previously described. Parameters such as the pressure drop between the inlet and outlet can be adjusted.

[0006] Preferred developments of the invention are the subject matter of the dependent claims.

[0007] Preferably, the housing has a seal between the cooling jacket and the housing closure structure. The seal has a cutout corresponding to the cross-section of the cooling channel, so that the coolant can pass from the cooling channel through the cutout to the deflection groove. The coolant can also pass from the deflection groove through the cutout to the cooling channel. Because one of the cooling channels is connected to the inlet and one of the cooling channels is connected to the outlet, a corresponding cutout is provided in the seal 11. A connecting channel is provided between the two cutouts, which is assigned to the cooling channel connected to the inlet and the cooling channel connected to the outlet. In this way, a bypass channel is implemented in the seal. The coolant can again pass from the inlet through the seal to the outlet, thereby bypassing the meandering cooling path through the housing.

[0008] In another preferred embodiment, the bypass channel is realized by a connecting groove in the cooling jacket and / or in the housing closure structure.

[0009] The bypass channel can thus be realized by simple and cost-effective production. In particular, only one groove can be machined into the cooling jacket and / or the housing closure structure, for example, by a milling process.

[0010] One of the housing enclosure structures particularly advantageously has both an inlet and an outlet. Provision is made for the inlet to be fluidically connected to the inlet groove and the outlet to be fluidically connected to the outlet groove of the corresponding housing enclosure structure. The inlet groove and the outlet groove are each fluidically connected to a separate cooling channel of the cooling jacket. In this case, the connecting groove connects the inlet groove and the outlet groove, so that a fluid connection exists between the inlet groove and the outlet groove, and therefore between the inlet and the outlet. The bypass channel is implemented in a particularly simple and cost-effective manner. The connecting groove can also be manufactured simply and inexpensively, for example, by milling. It is particularly preferred that the deflection groove, the connecting groove, the inlet groove, and the outlet groove are all arranged along the same annular track. This ensures simple and cost-effective manufacturing and assembly. Negative flow obstruction due to the connecting groove is also avoided.

[0011] The radial extents of the inlet, outlet, and connecting grooves are preferably identical. This further simplifies production. The combined circumferential extent of the inlet, outlet, and connecting grooves is preferably identical to the corresponding circumferential extent of each of the deflection grooves. This achieves a uniform structure for the housing enclosure.

[0012] The ratio of the height to the width of the bypass channel is preferably between 1.0 and 4.0. The ratio is particularly preferably between 1.2 and 3.5. This ratio achieves that the pressure loss along the entire cooling path between the inlet and the outlet is optimized.

[0013] The bypass channel advantageously begins upstream of the first cooling channel through which the coolant is to pass and ends downstream of the last cooling channel through which the coolant is to pass. This achieves an optimal detour of the meandering cooling path as described above. For this purpose, the bypass channel can, in particular, be provided in the seal and / or the housing closure and / or the cooling jacket, as described above.

[0014] The cooling medium is particularly preferably water or is designed to be based on water. The cooling medium can therefore be produced simply and cost-effectively, is harmless or slightly harmful to the environment, and enables reliable cooling of the housing of the electric machine and therefore in particular of the stator of the electric machine.

[0015] As already explained, the housing closure structure is preferably a bearing cap. These bearing caps are used to rotatably support the rotor of the electric machine. In particular, a rolling bearing is provided on which the rotor is rotatably supported on the housing closure structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] Figure 1 is a schematic cross-sectional view of an electric machine in which the present invention may be used;

[0018] Figure 2 is based on Figure 1 A schematic spatial diagram of a motor;

[0019] Figure 3 According to the first embodiment of the present invention Figure 1 and Figure 2 A schematic side view of a motor;

[0020] Figure 4 is a schematic diagram of a housing enclosing structure of a motor according to a first embodiment of the present invention;

[0021] Figure 5 is a schematic detail view of a housing enclosure structure of a motor according to a first embodiment of the present invention; and

[0022] Figure 6 is a schematic exploded view of a housing of a motor according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0023] Figure 1 An electric motor 1 in which the present invention can be used is schematically shown. The electric motor 1 has a housing 2 which includes a cooling jacket 2a. The cooling jacket 2a serves, in particular, to accommodate a stator 3 of the electric motor 1. The stator 3 can be used to drive a rotor 15 of the electric motor 1.

[0024] During operation of the electric machine 1 , the rotor 15 rotates about a central axis 100 . The central axis 100 is in particular also the central axis of the stator 3 and of the cooling jacket 2 a.

[0025] In order to be able to dissipate waste heat during operation of the electric machine 1 , the cooling jacket 2 a is provided with a plurality of cooling channels 4 a which extend between the end faces 17 of the cooling jacket 2 a , for example in an axial direction relative to the center axis 100 and for example parallel to one another.

[0026] A housing closure structure 2b is formed at each of the end sides 17, wherein the housing closure structure 2b is preferably designed as a bearing cover. In particular, it is provided that the rotor 15 is rotatably supported on the corresponding housing closure structure 2b via rolling bearings 16, wherein the rolling bearings 16 are arranged at Figure 1 The housing closure structure 2b can therefore be designed as a pure housing shell without accommodating the rolling bearing 16. In this case, it is provided that the rotor 15 is supported on the cooling jacket 2a via the rolling bearing 16.

[0027] The two housing closure structures 2b can be separate housing parts. Alternatively, one of the two housing closure structures 2b can be part of a cooling jacket 2a, which in this case is configured in a pot-like manner. This pot-shaped cooling jacket 2a has a hollow cylindrical cooling jacket section with cooling channels 4a extending between its (covered, inaccessible) end faces 17.

[0028] Two adjacent cooling channels 4a in each case in the cooling jacket 2a are fluidically connected to one another via a deflection groove 4b formed in the corresponding housing closure structure 2b, which will be referred to below as Figure 3 More accurate explanation.

[0029] A seal 11 is arranged between at least one of the housing closure structures 2b and the cooling jacket 2a. The seal 11 has cutouts 12 so that fluid can pass from the corresponding cooling channel 4a of the cooling jacket 2a to the corresponding deflection groove 4b of the housing closure structure 2b and vice versa.

[0030] Furthermore, it is provided that an inlet 5 and an outlet 6 are arranged on the housing closure 2b (cf. Figure 2 ). As in Figure 1 As shown in FIG, the inlet 5 is connected to the inlet groove 13. The cooling medium can enter one of the cooling channels 4a from the inlet groove 13 through the matching cutout 12 of the seal 11. The same description applies to the outlet 6 in reverse order, but this is Figure 1 Not shown in the figure.

[0031] Figure 2Schematically shows the Figure 1 In particular, it is shown that the housing 2 has a cooling jacket 2a and an end face 17 (see FIG. Figure 1 ). Only one of the housing enclosure structures 2b has an inlet 5 and an outlet 6.

[0032] exist Figure 3 Schematically shows how the cooling path extends through the housing 2. Therefore, it is provided that one of the two housing closure structures 2b, as already described, Figure 2 As shown in FIG, it has both an inlet 5 and an outlet 6. Furthermore, each housing enclosure 2b has a plurality of deflection grooves 4b. The deflection grooves 4b of the two housing enclosures 2b connect the cooling channels 4a in a meandering manner, thereby extending a continuous cooling path 10 from the inlet 5 to the outlet 6 in a meandering manner. This ensures that the coolant flows reliably through the housing 2 and can absorb heat from the entire stator. This ensures efficient cooling.

[0033] To reduce the pressure drop between inlet 5 and outlet 6, according to the present invention, a bypass channel 7 is provided in housing 2, for example, in a separate housing enclosure 2b. Cooling fluid can thus flow directly or unmediated from inlet 5 via bypass channel 7 to outlet 6, without having to enter cooling jacket 2a. This bypasses meandering cooling path 10. In an alternative design, bypass channel 7 can also connect two subregions of the meandering cooling path, thereby bypassing only a portion of meandering cooling path 10.

[0034] Figure 4 and 5 The schematic diagram shows a separate housing enclosure 2b of an electric machine 1 according to an embodiment of the present invention. The housing enclosure 2b has a plurality of deflection grooves 4b, which, as previously described, fluidically connect two adjacent cooling channels 4a of the cooling jacket 2a. Additionally, an inlet groove 13 is provided, which is fluidically connected to the inlet 5. An outlet groove 14 is fluidically connected to the outlet 6. The deflection grooves 4b, the inlet grooves 13, and the outlet grooves 14 are formed on end-side joint surfaces, which are designed to engage with joint surfaces of the cooling jacket 2a. The cooling channels 4a of the cooling jacket 2a open into the joint surfaces of the cooling jacket 2a via corresponding openings.

[0035] As especially Figure 5As shown in detail in FIG, the connecting groove 8 extends between the inlet groove 13 and the outlet groove 14, thereby forming the bypass channel 7. The connecting groove 8 can be produced simply and cost-effectively, for example, by milling. The ratio of the height h to the width b of the bypass channel 7 can be used to optimize the fluid flow through the meandering cooling path 10. Thus, an optimized pressure drop between the inlet 5 and the outlet 6 is achieved, in particular for a ratio of the height h to the width b of the bypass channel 7 between 1.0 and 4.0, preferably between 1.2 and 3.5.

[0036] The connecting groove 8, the inlet groove 13, the outlet groove 14, and the deflection groove 4b are arranged about the central axis 100, for example, on the same circular path. Furthermore, provision can be made for the radial extents of the connecting groove 8, the inlet groove 13, the outlet groove 14, and the deflection groove 4b to be identical. This allows for a simple and cost-effective housing enclosure 2b that is also optimized with respect to its cooling efficiency.

[0037] exist Figure 4 and 5 , it is shown that the connecting groove 8 is arranged in the joint surface of the separate housing closure structure 2b. The connecting groove 8 can also be arranged alternatively or additionally on the corresponding joint surface of the cooling jacket 2a.

[0038] Figure 6 Another possible configuration of the bypass channel 7 is shown.

[0039] Figure 6 1 is a schematic exploded view of at least a portion of a housing 2 of an electric machine 1 according to a second embodiment of the present invention.

[0040] The seal 11 therefore has a cutout 12 as already described. The cutout 12 is constructed corresponding to the cross section of the cooling channel 4a. If the bypass channel 7 is to be constructed in the seal 11, a connecting channel 9 is advantageously provided between two of the cutouts 12. Therefore, a cooling channel 4a which is fluidically connected to the inlet 5 is provided for one of the cutouts 12. A cooling channel 4a which is fluidically connected to the outlet 6 is provided for the other cutout 12. Thus, a feasible solution for the cooling medium is created, namely, a bypass cooling path 10 is created via the connecting channel 9. The bypass cooling path 10 is again carried out upstream of the first cooling channel 4a to be passed through and downstream of the last cooling channel 4a to be passed through the cooling jacket 2a. In Figure 6 In the embodiment shown, only the seal 11 is provided with the bypass channel 7. No changes to the cooling jacket 2a or the housing closure 2b are necessary. This results in simple and cost-effective production and assembly.

[0041] The exemplary embodiments described above can also be combined particularly advantageously, so that, for example, the realization of the bypass channel 7 is provided both in the seal 11 and in the housing closure 2 b.

[0042] In any case, the bypass channel 7 according to the invention achieves a reduction in the pressure drop between the inlet 5 and the outlet 6. In particular, the pressure drop can be set to a predetermined value in a simple and cost-effective manner by dimensioning the bypass channel.

Claims

1. A motor (1) having a housing (2), ·in, The housing (2) has a hollow cylindrical cooling jacket (2a) for accommodating the stator (3), and wherein the cooling jacket (2a) has a cooling channel (4a) extending between its end sides (17), wherein the housing (2) has a deflection groove (4b) so that two adjacent cooling channels (4a) are fluidically connected via the deflection groove (4b), so that the cooling channels (4a) and the deflection groove (4b) form a continuous, meandering cooling path (10) extending between the inlet (5) and the outlet (6) through the housing (2), through which a cooling medium can flow; It is characterized by: The housing has a housing closure (2b) on the end side, which is arranged on the cooling jacket (2a) and includes a deflection groove (4b), The housing (2) has a bypass channel (7) which connects the inlet (5) and the outlet (6) in fluid communication while bypassing a meandering cooling path (10), The bypass channel (7) is realized by a connecting groove (8) in the joint surface of the end side of the cooling jacket (2a) and / or the housing closure structure (2b), or is realized in a seal (11) arranged between the cooling jacket (2a) and the housing closure structure (2b) as a connecting piece of two cutouts (12) formed in the seal (11) and assigned to the cooling channel (4).

2. The electric motor (1) according to claim 1, characterized in that One of the housing enclosure structures (2b) has the inlet (5) and the outlet (6), wherein the inlet (5) is in fluid communication with an inlet slot (13) and the outlet is in fluid communication with an outlet slot (14) of the housing enclosure (2b), wherein the inlet slot (13) and the outlet slot (14) are in fluid communication with a separate cooling channel (4a) of the cooling jacket (2a), and The connecting groove connects the inlet groove (13) and the outlet groove (14) to each other in fluid communication.

3. The electric motor (1) according to claim 2, characterized in that The deflection groove (4b), the connecting groove (8), the inlet groove (13) and the outlet groove (14) are arranged along the same annular track.

4. The electric motor (1) according to claim 2 or 3, characterized in that The radial extensions of the inlet groove (13), the outlet groove (14) and the connecting groove (8) are consistent.

5. The electric machine (1) according to any one of the preceding claims 1 to 3, characterized in that The ratio of the height (h) to the width (b) of the bypass channel (7) is between 1.0 and 4.

0.

6. An electric machine (1) according to any one of the preceding claims 1 to 3, characterized in that The bypass channel (7) starts upstream of the first cooling channel (4b) to be traversed by the cooling medium and ends downstream of the last cooling channel (4b) to be traversed by the cooling medium.

7. An electric machine (1) according to any one of the preceding claims 1 to 3, characterized in that The cooling medium is water or is designed to be water-based.

8. An electric machine (1) according to any one of the preceding claims 1 to 3, characterized in that The rotor (15) is rotatably supported on the housing closure structure (4b).

9. The electric motor (1) according to claim 1, characterized in that The housing closing structure (2b) is a bearing cover.

10. The electric motor (1) according to claim 5, characterized in that The ratio of the height (h) to the width (b) of the bypass channel (7) is between 1.2 and 3.

5.

11. The electric motor (1) according to claim 8, characterized in that The rotor (15) is rotatably supported on the housing closure (4b) via a respective rolling bearing (16).

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