Search

EP-4407848-B1 - ROTARY ELECTRIC MACHINE

EP4407848B1EP 4407848 B1EP4407848 B1EP 4407848B1EP-4407848-B1

Inventors

  • UEMATSU, Taku

Dates

Publication Date
20260506
Application Date
20220824

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 bearing (8), the shaft (3) comprising a delivery portion including a tapered region (3a, 3b) having a tapered shape reduced in diameter as a distance from the rotor (2) increases; a stator (4) that has a cylindrical shape, accommodates the rotor (2) inside, and has a coil wound around an inner peripheral side; a rotor cover (12, 12a, 12b) attached to an axial end surface of the rotor (2); and a casing having a flow passage for supplying oil to the bearing (8), wherein the rotor cover (12, 12a, 12b) has an oil receiving portion (22) that protrudes axially with respect to the rotor cover (12, 12a, 12b) and covers an exterior of the tapered region (3a, 3b) of the shaft (3) and is disposed opposite the tapered region (3a, 3b), wherein a concentric clearance is formed between the oil receiving portion (22) and the tapered region (3a, 3b), the concentric clearance configured to store oil received from the bearing (8), wherein the oil receiving portion (22) has an injection port for injecting the oil guided to the concentric clearance toward an inner periphery of a coil end portion (7) by centrifugal force, and characterized in that the distal end of the oil receiving portion (22) protruding in the axial direction is opposite to the bearing (8) in the axial direction.
  2. The rotary electric machine (1) according to claim 1, wherein the rotor cover (12, 12a, 12b) includes an oil guide portion (23) on an outer peripheral side of the oil receiving portion (22), and the oil guide portion (23) includes an inclined surface that reflects the oil injected from the injection port, and adjusts a position where the coil is cooled by the oil.
  3. The rotary electric machine (1) according to claim 1 or 2, wherein the rotor cover (12, 12a, 12b) is made of metal and covers the axial end surface of the rotor (2), and the axial end surface of the rotor (2) is cooled by the oil via the rotor cover (12, 12a, 12b).
  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 spreads the oil from an upper side of the coil; 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 Conventionally, there has been known a rotary electric machine having a cooling structure for cooling that brings cooling oil into contact with a coil end portion of a stator in order to enhance cooling efficiency of a coil wound around a stator core. In this type of rotary electric machine having the cooling structure, the cooling oil is injected downward from the upper side of an axial end of the rotary electric machine to the coil end portion. The cooling oil takes heat when coming into contact with the coil end portion, and flows toward an oil pan on the lower side along an outer periphery of the coil end portion. In a case where the cooling oil is injected from the upper side of the rotary electric machine, in general, the cooling oil is not directly supplied to the inner peripheral side of the coil end portion, and is only indirectly cooled by oil bounced back after heat exchange, oil mist in a housing, or the like. Therefore, in the above configuration, a cooling effect by the oil on the inner peripheral side of the coil end portion is limited, and it is necessary to increase the overall supply amount of the cooling oil in order to enhance the cooling effect. Further, for example, as in Patent Literatures 1 and 2, there is also proposed a cooling structure in which an oil supply passage is formed inside a rotor shaft along the axial direction, and cooling oil from the rotor shaft is injected to the inner side of a coil by centrifugal force. EP 3 672 035 A1 describes a motor mounted in a vehicle and cooled by using oil. The rotor assembly includes a rotatable shaft extending in an axial direction, a rotor core coupled to the rotatable shaft and having a plurality of holes penetrating through the rotor core in the axial direction, a first end ring coupled to one end of the rotor core and configured to guide oil supplied to the rotor assembly into the plurality of holes, and a second end ring coupled to the opposite end of the rotor core and configured to guide oil passing through the plurality of holes in a radial direction. US 2012/049665 A1 describes systems and methods for cooling and lubrication of high power density electric machines with an enhanced fluid injection system. DE 10 2015 004070 A1 describes a cooling assembly for use with an electric machine having bearings, a shaft rotatably supported by the bearings, a rotor connected to the shaft, and a stator annularly surrounding the rotor. JP 4 990872 B2 describes a motor unit for vehicles, which can effectively suppress the temperature rise of a coil in a simple structure. JP 2005 006429 A describes a motor in which a stator coil end is cooled with a cooling oil efficiently with a simple structure. US 2010/320851 A1 describes a system for cooling an electrical machine. The electrical machine includes a stator including a plurality of coils, an exterior housing, and an end cap. Citation List Patent Literature Patent Literature 1: JP 2011-10489 APatent Literature 2: JP 2007-159325 A Summary of Invention Technical Problem However, in the cooling structure in which the oil is injected from the inside of the rotor shaft as in Patent Literatures 1 and 2, 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 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 Literatures 1 and 2. The present invention has been made in view of the above circumstances, and provides a rotary electric machine capable of injecting oil to an inner periphery of a coil without supplying the oil into a rotor shaft. The present invention is defined by the independent claims. Preferred examples are defined in the dependent claims. Advantageous Effects of Invention According to one aspect of the present invention, the oil can be injected to the inner periphery of the coil without supplying the oil into the rotor shaft. Brief Description of Drawings Fig. 1 is a perspective view illustrating an example of a rotary electric machine of the present embodiment.Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1.Fig. 3 is a front view of the rotary electric machine in a state where a housing cover on a load side is removed.Fig. 4 is a view illustrating an inner surface side of the housing cover on the load side.Fig. 5 is a perspective cutaway view of a rotor cover.Fig. 6 is an enlarged view of the vicinity of a bearing on the load side in Fig. 2. Description of Embodiments Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, structures and elements other than the main part of the present invention will be described in a simplif