Search

EP-3739728-B1 - TWO-PIECE STATOR HOUSING

EP3739728B1EP 3739728 B1EP3739728 B1EP 3739728B1EP-3739728-B1

Inventors

  • Pregelj, Borut

Dates

Publication Date
20260506
Application Date
20190513

Claims (14)

  1. An electric machine (100) comprising a two-piece housing (200) and a stator core (300) enclosed in said two-piece housing (200), - the stator core having - a front end and a rear end, and - a stator winding provided with a front end winding portion (310) and a rear end winding portion (320) which, respectively, protrude from the front and rear ends of the stator core, - the two-piece housing comprising a housing cover (210) and a main housing (220), - the housing cover having an inner wall, - the inner wall being provided with a first protruding portion (211) which protrudes towards the front end of the stator core and over the front end winding portion, - the main housing having an open end and a closed end, - the open end being removably attachable to the housing cover, - the closed end having an inner wall provided with a second protruding portion (212) which protrudes towards the rear end of the stator core and over the rear end winding portion, wherein, - the two-piece housing has an outer wall and an inner wall, - the inner wall of the two-piece housing being arranged to, when the two-piece housing encloses the stator core, define a plurality of spaced coolant channels (20) which are axially extending over the stator core and the first and second protruding portions, thereby allowing a coolant fluid to flow in the channels directly in contact with an outer surface of the stator core, the coolant fluid flowing in coolant channels (20) being indirectly in contact with the stator winding, wherein, - the two-piece housing further comprises a plurality of first connecting fluid passages (21) and at least one second connecting fluid passage (22), - the plurality of first connecting fluid passages and the second connecting fluid passage being arranged to transfer the coolant fluid between adjacent coolant channels, - the plurality of first connecting fluid passages being provided in the inner wall of the housing cover and in the inner wall of the closed end of the main housing, and the second connecting fluid passage being provided in the first and/or second protruding portions, wherein, - the two-piece housing further comprises at least one conduit (60, 61) formed radially through the outer wall of the two-piece housing, at a space arranged in the first and/or second protruding portions, between, on the one hand, the second connecting fluid passage, and, on the other hand, the inner wall of the housing cover and/or the inner wall of the closed end of the main housing.
  2. The electric machine of claim 1, wherein the two-piece housing (200) is further arranged to: - create a first gap between the first protruding portion and the front end winding portion, and - create a second gap between the second protruding portion and rear end winding portion, wherein the first and second gaps are filled with a thermally conductive and electrically insulating material (30).
  3. The electric machine of any one of claims 1 to 2, wherein the first and second protruding portions are arranged to be sealed to the front end and the rear end of the stator core, respectively.
  4. The electric machine of any one of claims 1 to 3, wherein the first connecting fluid passages are U-shaped.
  5. The electric machine of any one of claims 1 to 4, wherein the second connecting fluid passage is a transverse passage.
  6. The electric machine of any one of claim 1 to 5, wherein the first connecting fluid passages are closed with a single ring-shaped plate (40).
  7. The electric machine of any one of claim 1 to 6, in which the two-piece housing (200) comprises one second connecting fluid passages and two conduits, wherein each conduit is a liquid conduit fluidly coupled to one of the second connecting fluid passages, thereby allowing the flow of the coolant to and from the two conduits.
  8. The electric machine of any one of claim 1 to 7, in which the two-piece housing (200) further comprises a coolant channel end (23), the coolant end being arranged to prevent the coolant fluid flow between adjacent coolant channels, and being provided in the first and/or second protruding portions, wherein the conduit is formed at a space arranged in the first and/or second protruding portions, between, on the one hand, the coolant channel end, and, on the other hand, the inner wall of the housing cover and/or the inner wall of the closed end of the main housing.
  9. The electric machine of any one of claims 1 to 7, wherein the second connecting fluid passage is replaced by a coolant channel end (23), the coolant channel end being arranged to prevent the coolant fluid flow between adjacent coolant channels.
  10. The electric machine of claim 9, in which the two-piece housing (200) further comprises a second connecting fluid passage (22), the second connecting fluid passage arranged to transfer the coolant fluid between adjacent coolant channels, and being provided in the first and/or second protruding portions, wherein the conduit is formed at a space arranged in the first and/or second protruding portions, between, on the one hand, the second connecting fluid passage, and, on the other hand, the inner wall of the housing cover and/or the inner wall of the closed end of the main housing.
  11. The electric machine of any one of claim 1 to 10, wherein the conduit is an electrical conduit electrically coupled to the front end winding portion or the rear end winding portion, thereby allowing the stator winding to be coupled to a power source.
  12. The electric machine of any one of claim 1 to 11, wherein the housing cover is arranged to be positioned radially on the main housing.
  13. The electric machine of any one of claim 1 to 12, wherein the housing cover is arranged to be positioned axially on the stator core.
  14. Vehicle, in particular automotive, more particularly electric or hybrid vehicle, comprising an electric machine according to any one of claims 1 to 13.

Description

Technical Field The invention relates to a two-piece housing for enclosing a stator core of an electric machine. It also concerns an electric machine and a vehicle. Background Art Electric machines, such as generators and motors, which operate at a high performance level, usually generate excessive heat in the stator core and stator windings. Such heat can cause damage and/or reduction in performance or life of the electric machine. In that case, for instance, one can remove the heat by providing the electric machine with a water jacket having fluid passages through which a coolant fluid, such as water, is circulated. However, with this arrangement, the positioning of the water inlet/outlet is sometimes limited to specific locations on the water jacket. This creates an undesired situation where positioning a conduit, such as a water inlet/outlet, wherever necessary on the water jacket, is not easy. Patent documents US2012/025638A1, KR2011/0089717A, DE4104740A1 and FR3038795A1 disclose embodiments of electric machines comprising a housing with cooling channels. Summary of Invention The present invention provides an electric machine as described in the accompanying claims. It also provides a vehicle. The dependent claims will present some specific embodiments of the invention. These and other aspects of the invention will become apparent from the description of the invention which follows below. Brief description of drawings The description will describe further details, aspects and embodiments of the present invention, by way of example only, with reference to the drawings. In the drawings, like reference numbers identify like or similar elements. Elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. Fig. 1 is a schematic cross-sectional diagram of an electric motor.Fig. 2 is a cross-sectional view of the housing and the stator core of Fig. 1.Fig. 3 is a detailed view of Fig. 2.Figs. 4a, 4b, 5a, 5b, 6a, 6b, 7a and 7b are other detailed views of Fig. 2. Description of embodiments In order to solve the problem of easily positioning a conduit on a water jacket wherever necessary, the present invention provides a two-piece housing for enclosing a stator core of an electric machine. According to the invention, the two-piece housing enables direct liquid cooling of the stator core and indirect liquid cooling of the stator winding. In particular, the two-piece housing is so arranged to provide at least one free space in radial direction at any circumference angle. This way, at that location, one can easily position a conduit, such as a water inlet/outlet, wherever necessary on the two-piece housing. Fig. 1 illustrates an exemplary electric machine in accordance with embodiments of the present invention. In Fig. 1, the electric machine is an electric motor 100. However, one should note that one can use the teachings of the present invention with other electric motor configurations and other electric machines such as generators. In Fig. 1, electric motor 100 comprises a housing 200, a stator core 300, a shaft 400, and a rotor 500. Stator core 300 is made of a permeable magnetic material and is typically formed of laminations (not shown). Stator core 300 is substantially annular and generally surrounds rotor 500. Stator core 300 is arranged to remain stationary relative to housing 200 during operation of electric motor 100. Rotor 500 and shaft 400 are fixed together for unitary rotation. In particular, rotor 500 and shaft 400 can be rotated relative to housing 200 and stator core 300. Referring to Fig. 2, stator core 300 comprises a front end and a rear end. Stator core 300 further comprises a stator winding provided with a front end winding portion 310 and a rear end winding portion 320 which, respectively, protrude from the front end and the rear end of stator core 300. In Fig. 2, housing 200 is a two-piece housing defining an interior volume when combined. In particular, housing 200 comprises a housing cover 210 and a main housing 220 which are respectively arranged at the front axial end portion and rear axial end portion of electric motor 100. Housing cover 210 includes an inner wall. The inner wall of housing cover 210 is provided with a first protruding portion 211 which protrudes towards the front end of stator core 300 and over the front end winding portion 310. Main housing 220 includes an open end and a closed end. The open end of main housing 220 is removably attachable to housing cover 210. The closed end of main housing 220 includes an inner wall. The inner wall of the closed end of main housing 220 is provided with a second protruding portion 212 which protrudes towards the rear end of stator core 300 and over the rear end winding portion 320. In an embodiment, housing cover 210 and main housing 220 are arranged to be sealed together with suitable sealing elements such as O-rings. However, other sealing means can be contemplated. In particular, the op