Motor

Abstract

To provide a motor that can maintain cooling performance.SOLUTION: A motor 1 includes a rotor shaft 4 having at least two types of coolant flow passages, a first coolant flow passage 6 and a second coolant flow passage 7, formed separately along a rotation axis Xa.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a motor. [Background technology]

[0002] Patent Document 1 describes a technology for a rotating electric machine that includes a rotor having a hollow rotor shaft and rotor core, a stator having a stator core and coils, and a case member that houses the rotor and stator and has a cooling water passage formed therein for cooling the outside of the stator with cooling water. This technology provides an oil passage structure inside the hollow rotor shaft that supplies oil such as ATF (Automatic Transmission Fluid) discharged by an oil pump, and ensures cooling capacity for the rotating electric machine by heat exchange between the cooling water flowing in the cooling water passage in the case member and the oil discharged by the oil pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-30847 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the rotor is cooled by an oil passage for one type of oil, which reduces the cooling capacity for the rotor when the oil is hot, and since the oil and cooling water are cooled in separate locations outside the rotor, there is room for improvement.

[0005] The present disclosure has been made in view of the above, and has an object to provide a motor that can maintain cooling performance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the objectives, the motor of the present disclosure is a motor equipped with an axial cooling structure, and is equipped with a rotor shaft at the axial center, in which at least two types of coolant flow paths are each formed separately along the rotational axis direction. [Effects of the Invention]

[0007] According to the present disclosure, an effect is achieved in that cooling performance can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a motor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the rotor and rotor shaft taken along line AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Motors according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the drawings referred to in the following description merely show a schematic representation of the shape, size, and positional relationship to the extent that the contents of the present disclosure can be understood. In other words, the present disclosure is not limited to the shape, size, and positional relationship exemplified in each drawing.

[0010] [Motor configuration] Fig. 1 is a cross-sectional view showing the schematic configuration of a motor according to one embodiment. The motor 1 shown in Fig. 1 is mounted on, for example, a vehicle and is rotationally driven by an externally supplied current, such as a three-phase AC current. The motor 1 includes a substantially cylindrical stator 2 fixed to a frame (housing) or the like (not shown), a rotor 3 rotatably held on the inner periphery of the stator 2, and a rotor shaft 4.

[0011] Fig. 2 is a cross-sectional view of the rotor 3 and rotor shaft 4 taken along line AA in Fig. 1. Note that Fig. 1 is a cross-sectional view taken along line BB in Fig. 2. In Figs. 1 and 2, the axial direction of the rotor shaft 4 is defined as the X direction, the circumferential direction perpendicular to the rotor shaft 4 is defined as the Y direction, and the depth direction perpendicular to the rotor shaft 4 is defined as the Z direction.

[0012] 1 and 2, the stator 2 has a stator core 21 and a stator coil 22. The stator 2 is fixed to the inner peripheral surface side of a frame (housing) not shown.

[0013] The stator core 21 is formed using an annular member in which a plurality of electromagnetic steel plates are laminated as plate materials made of magnetic material. The stator core 21 is formed with an inner diameter set so as to have an annular gap (air gap) between its inner peripheral surface and the rotor 3.

[0014] The stator coils 22 are inserted into slots (not shown) formed in the stator core 21, and form magnetic poles according to the current supplied from outside. The stator coils 22 are composed of a first stator coil to which a U-phase current is supplied, a second stator coil to which a V-phase current is supplied, and a third stator coil to which a W-phase current is supplied out of the three-phase AC. These first to third stator coils are sequentially arranged in the circumferential direction of the stator core 21.

[0015] 1 and 2, the rotor 3 is attached to a rotor shaft 4 and is configured to be rotatable about a rotation axis Xa of the rotor shaft 4. The rotor 3 has a rotor core 31, a rotor coil 32, and a plurality of coolant flow paths 33.

[0016] Rotor core 31 is formed using an annular member in which a plurality of electromagnetic steel plates are laminated as plate materials made of magnetic material, similar to stator core 21. Rotor core 31 is formed with its outer diameter set so as to have the above-mentioned gap (air gap).

[0017] The rotor coil 32 is formed and housed in slots (not shown) of the rotor core 31 by winding a coil wire around each of a plurality of teeth (not shown) formed on the rotor core 31. Note that in Figures 1 and 2, the rotor coil 32 is represented by symbols only.

[0018] The plurality of coolant flow paths 33 are formed in the rotor core 31 along the rotation axis Xa of the rotor shaft 4, and discharge oil OL, which is coolant, from both ends of the rotor core 31. Here, for example, ATF or the like is used as the oil OL. The plurality of coolant flow paths 33 are provided at predetermined intervals, for example, at four locations at 90-degree intervals, around the rotation axis Xa of the rotor shaft 4 in the circumferential direction. Furthermore, some of the plurality of coolant flow paths 33 are branched so as to be connectable to coolant flow paths provided in the rotor shaft 4, which will be described later, and the oil OL flows in from the coolant flow paths provided in the rotor shaft 4.

[0019] As shown in Figures 1 and 2, the rotor shaft 4 has a fixed shaft 41 whose one axial end is fixed to a case (housing) not shown, and a rotating shaft 42 into which the fixed shaft 41 is inserted and which rotates around the rotation axis Xa.

[0020] The fixed shaft 41 is cylindrical (hollow) and has a flow path 411 into which coolant Wa supplied from an external pump (not shown) flows in. The fixed shaft 41 is formed so that its outer diameter is smaller than the inner diameter of the rotating shaft 42 to provide an air gap.

[0021] The rotating shaft 42 is a circular rod-shaped member whose inner diameter is larger than the outer diameter of the fixed shaft 41, and is rotatably supported on a support point 43 such as a bearing provided in a case (housing) not shown. The rotor 3 is attached to the outer periphery of the rotating shaft 42, and a drive transmission part 5 is attached to the inner periphery of the right end part, and the rotational driving force of the rotor 3 is transmitted to this drive transmission part 5.

[0022] The rotating shaft 42 is formed such that the inner circumferential hole 421 and the fixed shaft 41 have different axial lengths so that a gap K1 is formed between the inner circumferential hole 421 and the tip of the fixed shaft 41. As a result, the rotating shaft 42 is configured such that the coolant Wa is discharged from the flow path 411 of the fixed shaft 41 into the gap K1 between the fixed shaft 41 and the hole 421, and flows into one axial end (left end) of the rotor shaft 4 via the hole 421. In other words, the flow path 411 and the flow path 422 form a first coolant flow path 6 that cools the motor 1 by allowing the coolant Wa supplied from a cooling pump (not shown) to flow in and circulate to the cooling pump. Here, for example, LLC (Long Life Coolant) or the like is used as the coolant Wa.

[0023] Furthermore, the rotating shaft 42 has a plurality of flow paths 423 located outward of the rotational axis Xa from the first coolant flow path 6 and extending circumferentially around the rotational axis Xa, through which oil OL flows. The oil OL functions as a coolant for cooling the motor 1. Each of the flow paths 423 is provided at four locations on the rotating shaft 42 at predetermined intervals, for example, 90-degree intervals, along the circumferential direction around the rotational axis Xa of the rotor shaft 4. Each of the flow paths 423 has a partially overlapping section D1 extending along the rotational axis Xa. Specifically, each of the flow paths 423 partially overlaps with a partial section D1 of the first coolant flow path 6 so as to surround the partial section D1 of the first coolant flow path 6 from the outer periphery along the rotational axis Xa. More specifically, each of the flow paths 423 is provided on the rotating shaft 42 in parallel with the rotational axis Xa so as to overlap with the partial section D1 of the first coolant flow path 6 along the rotational axis Xa. Furthermore, each of the multiple flow paths 423 is connected to each of the multiple coolant flow paths 33 provided in the rotor core 31, and supplies oil OL from an oil pump or drive gear (not shown) to each of the multiple coolant flow paths 33. In other words, the multiple flow paths 423 and the multiple coolant flow paths 33 provided in the rotor core 31 form a second coolant flow path 7 that circulates the oil OL to cool the motor 1.

[0024] In this way, the second coolant flow path 7 and the first coolant flow path 6 are formed separately along the direction of the rotation axis Xa in the rotor shaft 4, so that the cooling effect can be maintained even when the temperature of either the coolant Wa or the oil OL is high. Furthermore, the second coolant flow path 7 and the first coolant flow path 6 can exchange heat between the coolant Wa and the oil OL in the partial overlapping section D1 extending along the direction of the rotation axis Xa. As a result, the motor 1 can maintain its cooling effect even when the temperature of either the coolant Wa or the oil OL is high.

[0025] According to the embodiment described above, the first coolant flow path 6 and the second coolant flow path 7 are formed separately along the direction of the rotation axis Xa in the rotor shaft 4, so that the cooling effect can be maintained even when the temperature of either the coolant Wa or the oil OL is high.

[0026] Furthermore, according to one embodiment, heat exchange between the coolant Wa and the oil OL can be carried out in the section D1 where the second coolant flow path 7 and the first coolant flow path 6 partially overlap and extend along the direction of the rotation axis Xa, so that the cooling effect can be maintained even if the temperature of either the coolant Wa or the oil OL is high.

[0027] In one embodiment, the coolant Wa circulates through the first coolant flow path 6, but the type of coolant Wa circulating through the first coolant flow path 6 can be changed as appropriate, and oil OL may also be used if the flow path is different.

[0028] In addition, in one embodiment, only the first coolant flow path 6 and the second coolant flow path 7 are formed separately on the rotor shaft 4, but this is not limited to this, and the rotor shaft 4 may be further provided with a coolant flow path through which another type of coolant circulates.

[0029] Further advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0030] Although some of the embodiments of the present application have been described in detail above with reference to the drawings, these are merely examples, and the present invention can be implemented in other forms that have undergone various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the disclosure of the present invention. [Explanation of symbols]

[0031] 1 motor 2 stator 3 rotors 4 rotor shaft 5. Drive transmission parts 6 First Coolant Flow Channel 7 Second Coolant Flow Path 21 Stator core 22 stator coil 31 rotor core 32 rotor coil 33 Coolant flow path 41 Fixed shaft 42 Rotating shaft 43 Support points 411,422,423 Flow path 421 holes Office Lady Oil Wa coolant Xa rotation axis

Claims

1. A motor equipped with a shaft cooling structure, a rotor shaft having at least two types of coolant flow paths formed separately along the rotation axis direction at its axis center; Motor.

2. 2. The motor according to claim 1, The rotor shaft The at least two types of coolant flow paths are a first coolant flow path and a second coolant flow path; Each of the first coolant flow path and the second coolant flow path comprises: a section that overlaps with the rotation axis direction; Motor.

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