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EP-4412057-B1 - ROTARY ELECTRICAL MACHINE

EP4412057B1EP 4412057 B1EP4412057 B1EP 4412057B1EP-4412057-B1

Inventors

  • UEMATSU Taku

Dates

Publication Date
20260506
Application Date
20220823

Claims (4)

  1. A rotary electric machine (1) comprising: a rotor (2); a shaft (3) that penetrates the rotor (2) along a rotation axis and is pivotally supported by a first bearing (8) at a load side and a second bearing (8) at an anti-load side; a stator (4) accommodating the rotor (2) inside; a first rotor cover (12a) attached to a first axial end surface of the rotor (2); a second rotor cover (12b) attached to a second axial end surface of the rotor (2); a casing having a flow passage for supplying oil to the first and second bearings (8), wherein the rotor (2) has void portions (10a) penetrating the rotor (2) in an axial direction, wherein each of the first and second rotor covers (12a, 12b) has an oil receiving portion (22) that forms a concentric clearance with respect to the shaft (3) and receives the oil from the respective bearing (8) in the respective clearance; an oil distribution passage (24) that communicates with the axial end surface of the rotor (2) from the oil receiving portion (22) and is connected to a void portion of the void portions (10a); and a discharge port (25) arranged at a position corresponding to another void portion of the void portions (10a) and for discharging oil guided by said void portion, wherein the first and the second rotor cover (12a, 12b) are configured for supplying the oil guided to the respective clearance to the oil distribution passage (24) by centrifugal force to cool the rotor (2), and wherein the oil distribution passage (24) and the discharge port (25) of the first and second rotor covers (12a, 12b) are arranged with phases shifted from each other between the load side and the anti-load side of the rotor (2) to alternately change flowing directions of the oil.
  2. The rotary electric machine (1) according to claim 1, wherein each of the void portions (10a) faces a magnet arranged in the rotor (2), and the oil flowing through the void portion (10a) comes into contact with the magnet.
  3. The rotary electric machine (1) according to claim 1, wherein the shaft (3) includes a delivery portion that protrudes in a radial direction inside the clearance and delivers the oil to the oil receiving portion (22).
  4. The rotary electric machine (1) according to any one of claims 1 to 3, wherein the casing further includes: an oil spreading portion that distributes the oil from an upper side of the coil provided on the stator (4); and an oil supply passage (13) for supplying the oil to the oil spreading portion, and the flow passage supplies the oil branching from the oil supply passage (13).

Description

Technical Field The present invention relates to a rotary electric machine. Background Art An event (high-temperature demagnetization) in which a magnetic flux decreases at a high temperature is likely to occur in a magnet accommodated in a rotor of a rotary electric machine. Such high-temperature demagnetization can also be suppressed by applying, for example, a magnet having a high content ratio of heavy rare earths, but this case leads to an increase in manufacturing cost of the rotary electric machine. In general, the rotor is air-cooled by heat dissipation to the air, but there is a demand for more efficient cooling of the rotor from the viewpoint of improving the performance of the rotary electric machine. For example, there is known a cooling structure in which a refrigerant such as oil flows in a rotor of a rotary electric machine in order to achieve cooling of the rotor and the like. As an example of this type of cooling structure, Patent Literature 1 proposes a configuration in which an oil supply passage is formed inside a rotor shaft along the axial direction, and cooling oil from the rotor shaft is supplied to a radially outer side of a rotor by centrifugal force. EP 3 672 035 AI describes a motor comprising a rotor assembly including a rotating shaft extending in one direction. US 2013/038151 A1 describes a rotary machine comprising a housing in which a stator is fixed, an outer housing attached to an outer side of the housing, a rotor shaft that horizontally passes through the housing, a rotor that is arranged inside the housing, a rotor shaft coolant path formed inside the rotor shaft, and a rotor coolant path formed inside the rotor. Citation List Patent Literature Patent Literature 1: JP 2010-220340 A Summary of Invention Technical Problem However, in the cooling structure in which oil is supplied from the inside of the rotor shaft to the rotor as in Patent Literature 1, it is necessary to sufficiently increase the pressure of the cooling oil with a pump in order to deliver the oil into the shaft, and it is also necessary to provide an oil seal at a portion for delivering the oil to the rotating shaft. Therefore, a cost of the cooling structure increases. Further, the rigidity of the rotor shaft may also decrease because the rotor shaft has a hollow structure in Patent Literature 1. The present invention has been made in view of the above circumstances, and provides a rotary electric machine capable of cooling a rotor by oil without forming a flow passage of the oil in a rotor shaft. The present invention is defined by independent claim. Preferred examples are defined in the dependent claims. Advantageous Effects of Invention According to one aspect of the present invention, the rotor can be cooled by the oil without forming the flow passage of the oil in the rotor shaft. Brief Description of Drawings Fig. 1 is a perspective view illustrating an example of a rotary electric machine not covered by the present invention.Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1.Fig. 3 is a front view illustrating an axial end surface of a rotor not covered by the present invention.Fig. 4 is a front view of the rotary electric machine in a state where a housing cover on a load side is removed.Fig. 5 is a view illustrating an inner surface side of the housing cover on the load side.Fig. 6 is a perspective cutaway view of a rotor cover on the load side.Fig. 7 is a perspective view of the rotor, not covered by the present invention, from the load side.Fig. 8 is an enlarged view of the vicinity of a bearing on the load side in Fig. 2. Description of Embodiments Hereinafter, an example of the known electric machine will be described in §15 - §57 with reference to the drawings. Fig. 4, 5, 6 and 8 disclose parts of the invention related to the design of the rotor load side and load side rotor cover 12a. Fig. 1, 2, 3 and 7 disclose configuration of the cooling structure according to the state of the art which is useful for understanding the present invention. Main aspects of the invention are defined in §58 of the detailed description. Further embodiment of the invention is disclosed in §59. In the embodiment, structures and elements other than the main part of the present invention will be described in a simplified or omitted manner in order for easy understanding. Further, the same elements are denoted by the same reference signs in the drawings. Note that shapes, dimensions, and the like of the respective elements illustrated in the drawings are schematically illustrated, and do not indicate actual shapes, dimensions, and the like. In the drawings, an XYZ coordinate system is illustrated appropriately as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, a Z direction is a direction parallel to a rotation axis. An X direction is a direction orthogonal to the Z direction and corresponds to a direction perpendicular to the paper surface of Fig. 2. A Y direction is a