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EP-4042546-B1 - ELECTRICAL MACHINE WITH BYPASS COOLING DUCT

EP4042546B1EP 4042546 B1EP4042546 B1EP 4042546B1EP-4042546-B1

Inventors

  • BENSING, Felix
  • MUELLER, FLORIAN
  • HEITZER, Simon Michael
  • Ender, Stefan

Dates

Publication Date
20260513
Application Date
20200811

Claims (8)

  1. Electrical machine (1) having a housing (2), - wherein the housing (2) has a hollow-cylindrical cooling jacket (2a) to accommodate a stator (3), and - wherein the cooling jacket (2a) has cooling ducts (4a) running between its end sides (17), - wherein the housing (2) has redirecting grooves (4b) so that two adjacent cooling ducts (4a) are fluidically connected by a redirecting groove (4b), whereby the cooling ducts (4a) and redirecting grooves (4b) form a continuous cooling path (10) through the housing (2), said cooling path running in meandering fashion between an inlet (5) and an outlet (6) and being able to be flowed through by a coolant, characterized in that - the housing (2) has, attached to the end sides on the cooling jacket (2a), housing closures (2b), in particular mounting plates, which comprise the redirecting grooves (4b), - the housing (2) has a bypass duct (7) which fluidically connects the inlet (5) and the outlet (6) while bypassing the meandering cooling path (10), - the bypass duct (7) is formed by a connecting groove (8) in an end-side joining face of the cooling jacket (2a) and/or of the housing closure (2b) or in a seal (11), arranged between the cooling jacket (2a) and the housing closure (2b), as a connection of two cutouts (12) which are formed in the seal (11) and which are associated with the cooling ducts (4a).
  2. Electrical machine (1) according to Claim 1, characterized in that one of the housing closures (2b) has the inlet (5) and the outlet (6), - wherein the inlet (5) is fluidically connected to an inlet groove (13) and the outlet is fluidically connected to an outlet groove (14) of the housing closure (2b), - wherein the inlet groove (13) and the outlet groove (14) are each fluidically connected to an individual cooling duct (4a) of the cooling jacket (2a), and - wherein the connecting groove (8) fluidically connects the inlet groove (13) and the outlet groove (14).
  3. Electrical machine (1) according to Claim 2, characterized in that the redirecting grooves (4b), the connecting groove (8), the inlet groove (13) and the outlet groove (14) are arranged along the same circular path.
  4. Electrical machine (1) according to Claim 2 or 3, characterized in that the radial extents of the inlet groove (13), the outlet groove (14) and the connecting groove (8) are identical.
  5. Electrical machine (1) according to one of the preceding claims, characterized in that a ratio of height (h) to width (b) of the bypass duct (7) is between 1.0 and 4.0, preferably between 1.2 and 3.5.
  6. Electrical machine (1) according to one of the preceding claims, characterized in that the bypass duct (7) starts upstream of the first cooling duct (4b) to be passed through by the coolant and ends downstream of the last cooling duct (4b) to be passed through by the coolant.
  7. Electrical machine (1) according to one of the preceding claims, characterized in that the coolant is water or is water-based.
  8. Electrical machine (1) according to one of the preceding claims, characterized in that a rotor (15) is mounted rotatably on the housing closures (4b), in particular via a rolling bearing (16) in each case.

Description

State of the art The present invention relates to an electric machine. The electric machine has a cooling path through its housing, wherein a bypass channel to said cooling path is provided. Electrical machines are known from the prior art. As the power output of the electrical machine increases, cooling becomes necessary. This is typically achieved by creating a meandering coolant path through the housing of the electrical machine. For example, the DE 10 2012 215 018 A1 such a machine. From the DE 10 2016 225 521 A1 An electrical machine is known which has a housing in which a meandering cooling path is formed and which has a bypass channel which fluidly connects two sub-areas of the meandering cooling path by bypassing part of the meandering cooling path. Disclosure of the invention The electrical machine according to the invention enables flexible adjustment of the parameters heat transfer and pressure drop. Thus, despite the use of an axially centrally oriented profile section, the cooling jacket, the ability to influence the heat transfer behavior and the pressure drop of the cooling process is increased compared to the prior art. The electric machine according to the invention has a housing. The housing, in turn, comprises a hollow cylindrical cooling jacket and housing end caps attached to the end faces of the cooling jacket. The housing end caps are, in particular, bearing shields. The cooling jacket serves to accommodate a stator of the electric machine. Thus, the stator of the electric machine can be The machine is cooled by the cooling jacket. The cooling jacket has cooling channels that extend between its end faces. The housing ends, in turn... The cooling channels feature deflection grooves. These grooves and channels are fluidly connected such that two adjacent cooling channels are fluidly connected to a single deflection groove. In this way, the cooling channels and grooves form a continuous cooling path. This cooling path extends through the housing between an inlet and an outlet. The cooling path is designed to meander through the housing. A coolant can flow along this path, thus cooling the housing and, in particular, the stator of the electric machine. According to the invention, the housing has a bypass channel. The bypass channel connects the inlet and outlet, bypassing the meandering cooling path. This allows a portion of the coolant supplied to the inlet to flow directly to the outlet via the bypass channel. This, in particular, reduces parameters such as the pressure drop between the inlet and outlet. Alternatively, the bypass channel can connect two sections of the meandering cooling path, in which case only a portion of the meandering cooling path is bypassed. The fundamental function of the bypass channel remains the same as described above. In particular, parameters such as the pressure drop between the inlet and outlet can be adjusted. The dependent claims contain preferred further developments of the invention. Preferably, the housing has a seal between the cooling jacket and the housing end. The seal has cutouts corresponding to the cross-section of the cooling channels, allowing the coolant to flow from the cooling channel through the cutout to the deflection groove. Likewise, the coolant can flow from the deflection groove to the cooling channel through the cutout. Since one of the cooling channels is connected to the inlet and one to the outlet, corresponding cutouts are provided in the seal 11. A connecting channel is provided between the two cutouts, one for the cooling channel connected to the inlet and the other for the cooling channel connected to the outlet. In this way, the A bypass channel is implemented in the seal. This allows the coolant to flow from the inlet through the seal to the outlet, bypassing the meandering cooling path through the housing. In one embodiment of the invention, the bypass channel is implemented by means of a connecting groove in the cooling jacket and/or the housing end. Thus, the bypass channel can be implemented through simple and cost-effective manufacturing. In particular, only a groove needs to be machined into the cooling jacket and/or the housing end, for example by a milling operation. Advantageously, one of the housing ends has both an inlet and an outlet. The inlet is fluidly connected to an inlet groove and the outlet to an outlet groove of the respective housing end. The inlet groove and the outlet groove are each fluidly connected to a single cooling channel of the cooling jacket. In this case, the connecting groove links the inlet groove and the outlet groove, thus establishing fluid communication between the inlet and outlet grooves. This allows for a simple and cost-effective implementation of the bypass channel. The connecting groove can be manufactured easily and with minimal effort, for example, by milling. It is particularly preferred that the deflection grooves, the connecting groove, the inlet groove, and the outle