Stator core

Abstract

This stator core is to be used in a rotary electric machine, and is provided with: a hollow cylindrical core body; and a cooling flow path that has an opening part at each of a first surface and a second surface, which are both end surfaces in the axial direction of the core body, connects between said both end surfaces, and is for passing a cooling oil thereinside. In the first surface, a surface lipophilic region which is a lipophilic region in contact with the opening part is formed around the opening part, and an oil-repellent region is formed outside the surface lipophilic region when viewed from the opening part.

Description

stator core

[0001] The present invention relates to a stator core.

[0002] Rotating electric machines generate heat during operation. The greater the output of a rotating electric machine, the greater the heat generated, and cooling using a cooling medium such as oil is widely practiced. Patent Document 1 discloses a rotating electric machine that includes a stator having a stator core and a stator coil, a rotor that rotates relative to the stator, a coolant supply port that supplies a coolant to coil ends protruding from the stator core, and a guide member that is provided along at least a portion of the coil ends and that guides the coolant supplied through the coolant supply port along the coil ends.

[0003] JP 2011-035992 A

[0004] The invention described in Patent Document 1 leaves room for improvement in the cooling configuration.

[0005] A stator core according to a first aspect of the present invention is used in a rotating electric machine, and comprises a hollow cylindrical core body, a cooling flow path having openings on first and second axial end faces of the core body, the cooling flow path communicating between the end faces and through which cooling oil passes, a surface lipophilic region that is an lipophilic region in contact with the opening is formed around the opening on the first face, and an oil-repellent region is formed outside the surface lipophilic region as viewed from the opening.A stator core according to a second aspect of the present invention is used in a rotating electric machine, and comprises a hollow cylindrical core body, and a plurality of cooling flow paths having openings on first and second axial end faces of the core body, the first and second axial end faces of the core body, the cooling flow path communicating between the end faces and through which cooling oil passes, the core body is formed with a plurality of slots into which coils are inserted, and an oil-repellent region is formed in at least one of the openings on the first face in a straight line with the nearest slot.

[0006] According to the present invention, the cooling oil can cool a wide area of ​​the stator core.

[0007] Cross-sectional view of a rotating electric machine Front view of a stator core Diagram showing surface treatment of a core body in an embodiment Diagram explaining effects Cross-sectional perspective view of a stator core in Modification 1 Diagram showing surface treatment of a core body in Modification 2 Diagram showing a core body in Modification 3 Enlarged view of an outer peripheral groove in Modification 3 Diagram showing surface treatment of a core body in Modification 5

[0008] -Embodiment- Hereinafter, an embodiment of a stator core according to the present invention will be described with reference to Figs.

[0009] FIG. 1 is a cross-sectional view of a rotating electric machine 100. Each drawing of this embodiment also shows mutually orthogonal X, Y, and Z axes. The rotating electric machine 100 includes a stator core 10 that generates heat during operation. The stator core 10 has a circular ring shape, and the axis of the ring is parallel to the X axis. The stator core 10 has a first surface 10S1 and a second surface 10S2, which are both axial end surfaces. The stator core 10 includes a cooling channel 11 that is parallel to the axial direction. The cooling channel 11 penetrates from the first surface 10S1 to the second surface 10S2, and cooling oil flows through the cooling channel 11 to cool the stator core 10. The cooling oil is supplied, for example, from an oil filler port 21 at the upper right of the figure and reaches the first surface 10S1 via the cooling channel 11. The negative side of the Z axis corresponds to the direction of gravity, and the cooling oil moves from the positive side of the Z axis to the negative side of the Z axis, i.e., from the top to the bottom of the figure. The cooling oil flowing from above due to gravity is collected in an oil reservoir 22 at the bottom of the figure, and is then moved to the positive side of the Z axis by a pump (not shown) or the like, where it cools the stator core 10 again.

[0010] FIG. 2 is a front view of the stator core 10. FIG. 2 shows the front of the stator core 10 as viewed from the negative side of the X-axis in FIG. 1, i.e., the first surface 10S1. As shown in the lower part of FIG. 2, the front view of the stator core 10 has a generally circular ring shape. FIG. 2 also shows an enlarged view of the area enclosed by the dashed trapezoid. The core body 10C constituting the stator core 10 has cooling channels 11 arranged at equal intervals on the outer periphery and teeth 12 and slots 13 arranged on the inner periphery. Coils 14 are arranged in each slot 13. The cooling channels 11 extend through to the second surface 10S, which is the other end face of the core body 10C located on the positive side of the X-axis, i.e., the far side in the figure. Hereinafter, the intersections of the cooling channels 11 and the first surface 10S1 or the second surface 10S2 are also referred to as openings 11P. In FIG. 2, there are an equal number of openings 11P, teeth 12, and slots 13. The slot 13 exists on a straight line connecting the center of the annulus of the core body 10C and the opening 11P.

[0011] FIG. 3 is a diagram showing the surface treatment of the core body 10C. The surface of the core body 10C is divided into an oleophilic region 10L, which is easily absorbed by the cooling oil, and an oleophobic region 10R, which repels the cooling oil. However, a portion of the surface of the core body 10C may be a region that is neither the oleophilic region 10L nor the oleophobic region 10R, such as an untreated region 10N that has not undergone any special treatment. The cooling oil easily penetrates the oleophilic region 10L and is difficult to penetrate the oleophobic region 10R. In FIG. 3, the oleophilic region 10L is indicated by dotted hatching, and the oleophobic region 10R is indicated by diagonal hatching. However, for convenience of drawing, the coil 14 is not shown in FIG. 3.

[0012] The lipophilic region 10L and the lipophobic region 10R are formed by applying known paints. The lipophilic region 10L is disposed around the opening 11P, and the lipophobic region 10R is formed outside the lipophilic region 10L as viewed from the opening 11P. The lipophobic region 10R can also be said to be disposed between the opening 11P and the slot 13. Note that hereinafter, the lipophilic region 10L formed on the first surface 10S1 shown in FIG. 3 will also be referred to as the "surface lipophilic region 10LF."

[0013] 4 is a diagram illustrating the effect. In this embodiment, the cooling oil flowing out from the opening 11P moves through the lipophilic region 10L and flows toward the slot 13 or the inner diameter side. Therefore, in this embodiment, the cooling oil can cool a wide range of the stator core 10. In contrast, in a comparative example in which the lipophilic region 10L or the lipophobic region 10R is not formed on the surface of the core body 10C, the cooling oil sometimes flows in a straight line from the opening 11P toward the slot 13, resulting in insufficient cooling of the surface of the core body 10C by the cooling oil.

[0014] The above-described embodiment provides the following advantageous effects. (1) The stator core 10 is used in a rotating electric machine 100 and includes a hollow cylindrical core body 10C and a cooling flow path 11 having openings 11P in a first surface 10S1 and a second surface 10S2, which are both axial end surfaces of the core body 10C. The cooling flow path 11 communicates between the both end surfaces and through which cooling oil passes. A surface lipophilic region 10LF, which is an lipophilic region in contact with the opening 11P, is formed around the opening 11P in the first surface 10S1. An oil-repellent region 10R is formed outside the surface lipophilic region 11LF as viewed from the opening 11P. Therefore, as described with reference to FIG. 4 , the cooling oil can cool a wide area of ​​the stator core 10.

[0015] (2) The core body 10C is formed with a plurality of slots 13 into which the coils 14 are inserted. The oil-repellent region 10R is formed on a straight line connecting the opening 11P and the slot 13. This prevents the cooling oil from flowing linearly from the opening 11P to the slot 13, thereby increasing the travel distance of the cooling oil on the first surface 10S1, i.e., the area to be cooled.

[0016] (Variation 1) Fig. 5 is a cross-sectional perspective view of the stator core 10 in Variation 1. However, Fig. 5 shows only a cut-out portion of the stator core 10. The slots 13 are regions sandwiched between the teeth 12, and in Fig. 5, they exist on the front and back sides of the teeth 12. The upper part of the figure is the first surface 10S1, and the arrangement of the openings 11P, oil-repellent regions 10R, and surface lipophilic regions 11LF is the same as in the embodiment. In this variation, side lipophilic regions 10LS, which are insulating lipophilic regions, are formed on the side surfaces of the teeth 12 that are approximately perpendicular to the first surfaces 10S1.

[0017] According to this first modification, in addition to the effects of the embodiment, the following effects are obtained: (3) The core body 10C is provided with slots 13 and a plurality of teeth 12 that separate the slots 13. Side lipophilic regions 10LS, which are insulating lipophilic regions, are formed on the side surfaces of the teeth 12 that are approximately perpendicular to the first surface 10S1. Therefore, insulating paper is not required between the coil 14 and the teeth 12.

[0018] (Variation 2) Figure 6 is a diagram showing the surface treatment of the core body 10C in Variation 2. In the embodiment, the entire first surface 10S1 of the tooth 12 is the surface lipophilic region 11LF. However, the innermost periphery may be an untreated region 10N that is not subjected to any special treatment. In other words, the surface of the tooth 12 excluding the innermost periphery may be the surface lipophilic region 11LF. There is no particular limitation on the length d of the untreated region 10N, and it may, for example, exceed the length D of the slot 13.

[0019] In addition to the effects of the embodiment, the second modification provides the following effects: (4) A lipophilic region is formed on the surface of the teeth 12, excluding the innermost periphery, of the first surface 10S1. This makes it easier for the cooling oil to flow into the slots 13 rather than the inner periphery of the core body 10C, and makes it easier for the cooling oil to come into contact with the coils 14 arranged in the slots 13 and remove heat.

[0020] 7 is a diagram showing a core body 10C according to Modification 3. The difference from the embodiment is that a peripheral groove 15 extending in the axial direction is provided on the outer periphery. Only one peripheral groove 15 may be provided, two peripheral grooves 15 may be provided at a phase of 180 degrees, or three or more peripheral grooves 15 may be provided.

[0021] Fig. 8 is an enlarged view of the peripheral groove 15. Specifically, the upper part of Fig. 8 shows a perspective view of the peripheral groove 15, and the lower part of Fig. 8 shows a front view of the peripheral groove 15. Fig. 8 shows that the peripheral groove 15 extends from the first surface 10S1 to the second surface 10S2. In addition, a groove lipophilic region 15L, which is a lipophilic region, is formed at the end of the peripheral groove 15 on the first surface 10S1 side.

[0022] According to Modification 3, in addition to the effects of the embodiment, the following effects are obtained. (5) The core body 10C has an outer circumferential groove 15 extending in the axial direction on the outer periphery. A groove lipophilic region 15L is formed at the end of the first surface side 10S1 of the outer circumferential groove 15. Therefore, it is possible to guide the cooling oil to the outer circumferential groove 15 while minimizing the deterioration of cooling performance. If the entire outer circumferential groove 15 were made into an lipophilic region, the entire outer circumferential groove 15 would be covered with a coating, which would reduce the area of ​​direct contact between the cooling oil and the core body 10C and reduce the cooling effect.

[0023] (6) A plurality of outer peripheral grooves 15 are provided, which allows the cooling oil to flow more easily.

[0024] (Variation 4) In the embodiment, the lipophilic surface region 10LF and the lipophobic surface region 10R are formed on the first surface 10S1. However, the lipophilic surface region 10LF and the lipophobic surface region 10R may be formed not only on the first surface 10S1 but also on the second surface 10S2. The lipophilic surface region 10LF formed on the second surface 10S2 is also referred to as the "second surface lipophilic region."

[0025] In addition to the effects of the embodiment, the fourth modification provides the following effects: (7) A second-surface lipophilic region, which is a lipophilic region in contact with the opening 11P, is formed around the second surface of the core body 10C. This allows the cooling oil to cool a wide area of ​​the stator core 10 on both sides of the core body 10C.

[0026] (Modification 5) Fig. 9 is a diagram showing the surface treatment of the core body 10C in Modification 5. In the embodiment, the surface lipophilic region 10LF and the oil-repellent region 10R are formed on the first surface 10S1. However, as shown in Fig. 9, the surface lipophilic region 10LF does not have to be provided on the first surface 10S1. Fig. 9 shows the modification of Fig. 3 in the embodiment, where the surface lipophilic region 10LF is replaced by an untreated region 10N.

[0027] Modification 5 provides the following advantageous effects: (8) In at least one opening 11P in the first surface 10S1, an oil-repellent region 10R is formed on a straight line with the nearest slot 13. Therefore, even if no lipophilic region is provided, the cooling oil can cool a wide area of ​​the stator core 10.

[0028] In the above-described embodiment, the center of the core body 10C, the slots 13, and the openings 11P are aligned on a straight line. However, they may be out of phase with each other, or the number of slots 13 and the number of openings 11P may differ.

[0029] The above-described embodiments and modifications may be combined with each other. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0030] 10: Stator core 10C: Core body 10L: Lipophilic region 10LF: Surface lipophilic region 10LS: Side lipophilic region 10N: Untreated region 10R: Lipophilic region 10S1: First surface 10S2: Second surface 11: Cooling flow path 11LF: Surface lipophilic region 11P: Opening 12: Teeth 13: Slot 14: Coil 15: Circumferential groove 15L: Groove lipophilic region 100: Rotating electric machine

Claims

1. A stator core for use in a rotating electric machine, comprising: a hollow cylindrical core body; and a cooling flow path having openings on a first face and a second face which are both axial end faces of the core body, communicating between the both end faces and through which cooling oil passes, wherein a surface lipophilic region which is an lipophilic region in contact with the opening is formed around the opening on the first face, and an oil-repellent region is formed outside the surface lipophilic region when viewed from the opening.

2. A stator core as claimed in claim 1, wherein the core body is formed with a plurality of slots into which coils are inserted, and the oil-repellent area is formed on a straight line connecting the opening and the slot.

3. A stator core as described in claim 1, wherein the core body is provided with a plurality of slots into which coils are inserted and a plurality of teeth separating the slots, and a side lipophilic area which is an insulating lipophilic area is formed on the side of the teeth which is approximately perpendicular to the first surface.

4. A stator core as described in claim 1, wherein the core body is provided with a plurality of slots into which coils are inserted and a plurality of teeth separating the slots, and a lipophilic region is formed on the surface of the teeth on the first face, excluding the innermost circumference.

5. A stator core as claimed in claim 1, wherein the core body has an outer circumferential groove extending in the axial direction on its outer periphery, and a lipophilic region is formed at the end of the outer circumferential groove on the first surface side.

6. A stator core according to claim 5, wherein a plurality of said outer peripheral grooves are provided.

7. A stator core according to claim 1, wherein a second-face surface lipophilic region is formed around the opening on the second face, the second-face surface being a lipophilic region in contact with the opening.

8. A stator core for use in a rotating electric machine, comprising: a hollow cylindrical core body; and a plurality of cooling passages having openings on a first face and a second face which are both axial end faces of the core body, communicating between the both end faces and through which cooling oil passes, wherein a plurality of slots into which coils are inserted are formed in the core body, and an oil-repellent region is formed in at least one of the openings in the first face in a straight line with the closest slot.