Rotating electrical machine

Abstract

Provided is a rotary electric machine that suppresses local increases in surface pressure generated on a stator by using a housing with improved circularity, and that improves reliability. The rotary electric machine of the present invention has a rotor, a stator, and a cylindrical housing that fixes the stator from the outer periphery side, the housing having a flange that extends in the outer peripheral direction on the axial end portion of the outer peripheral surface, the flange having a recess that extends in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine. Background Art

[0002] As background technology in this technical field, there is Japanese Patent Application Publication No. 2011-239576 (Patent Document 1). This publication describes a rotating electrical machine in which a folded portion is formed on a housing to which a stator is fitted, curved in a radial direction and extending toward the rotation axis. This folded portion extends to absorb dimensional variations among the stator components and suppress the increase in surface pressure generated on the stator.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-239576 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Patent Document 1 describes a rotating electric machine that suppresses the increase in surface pressure generated on the stator. However, the rotating electric machine described in Patent Document 1 has a structure in which the ends of the casing are welded, which raises concerns about plastic deformation of the material caused by this welding. Furthermore, there is concern about deterioration in the roundness of the casing due to the welded ends.

[0008] The present invention provides a rotating electrical machine that suppresses an increase in surface pressure generated on a stator and improves reliability by using a housing with improved roundness.

[0009] Technical means to solve the problem

[0010] In order to solve the above problems, the rotating electric machine of the present invention comprises: a rotor, a stator and a cylindrical housing for fixing the stator from the outer peripheral side. The housing has a flange extending in the outer peripheral direction at the axial end of the outer peripheral surface, and the flange has a recess extending in the circumferential direction.

[0011] Effects of the Invention

[0012] According to the present invention, a rotating electrical machine is provided that suppresses an increase in surface pressure generated on a stator and improves reliability by using a housing with improved roundness.

[0013] Other problems, structures, and effects than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. 1 is an exploded perspective view of the rotating electrical machine 100 according to the present embodiment.

[0015] Figure 2 FIG. 1 is a perspective view of the appearance of the rotating electrical machine 100 according to the present embodiment.

[0016] Figure 3 FIG. 1 is a partial perspective view of the rotating electrical machine 100 according to the present embodiment.

[0017] Figure 4 FIG. 4 is a perspective view of the appearance of the casing 400 of this embodiment.

[0018] Figure 5 FIG. 1 is a partial cross-sectional view of the rotating electrical machine 100 according to this embodiment.

[0019] Figure 6 This is an explanatory diagram showing the influence of the roundness of the housing on the magnetic characteristics of the stator (the relationship between the magnetic field intensity and the magnetic flux density) in this embodiment.

[0020] Figure 7 This is an explanatory diagram showing the influence of the roundness of the housing on the magnetic characteristics of the stator (the relationship between the magnetic flux density and the iron loss) in this embodiment.

[0021] FIG8(a) is a perspective view showing a first step of a method for manufacturing the housing 400 according to the comparative example.

[0022] FIG8(b) is an explanatory diagram showing the second step of the method for manufacturing the casing 400 of the comparative example.

[0023] FIG8(c) is an explanatory diagram showing the third step of the method for manufacturing the casing 400 of the comparative example.

[0024] FIG8(d) is an explanatory diagram showing the fourth step of the method for manufacturing the casing 400 of the comparative example.

[0025] FIG8(e) is an explanatory diagram showing the fifth step of the method for manufacturing the casing 400 of the comparative example.

[0026] FIG8(f) is an explanatory diagram showing the sixth step of the method for manufacturing the casing 400 of the comparative example.

[0027] FIG9(a) is a perspective view showing a first step of the method for manufacturing the housing 400 according to this embodiment.

[0028] FIG9(b) is an explanatory diagram showing the second step of the method for manufacturing the casing 400 according to this embodiment.

[0029] FIG9(c) is an explanatory diagram showing the third step of the method for manufacturing the casing 400 according to this embodiment.

[0030] FIG9(d) is an explanatory diagram showing the fourth step of the method for manufacturing the casing 400 according to this embodiment.

[0031] Fig. 9 (e) is an explanatory view showing the fifth step of the manufacturing method of the case 400 of the present embodiment.

[0032] Fig. 9 (f) is an explanatory view showing the sixth step of the manufacturing method of the case 400 of the present embodiment.

[0033] Figure 10 Fig. 10 (a) is a partial appearance perspective view of the case 400 of another embodiment. DETAILED DESCRIPTION

[0034] Hereinafter, an embodiment of the present application will be described with reference to the drawings. In addition, in each drawing, the same components are marked with the same symbols, and sometimes the description thereof is omitted for the repeated parts.

[0035] Embodiment 1

[0036] A rotating electric machine for an automobile, a generator, or the like is required to be high-output, and the rotating electric machine is also large-sized along with the high output. Thus, the holding force of a stator fitted by a case of the rotating electric machine becomes large, and the surface pressure generated on the stator also increases.

[0037] In the case where the surface pressure generated on the stator increases like this, there is a possibility that an electromagnetic steel sheet located at an end surface of the stator is damaged, and it is important to reduce the stress on the stator.

[0038] Figure 1 Fig. 1 (a) is an exploded perspective view of a rotating electric machine 100 of the present embodiment.

[0039] The rotating electric machine 100 is constituted by a rotor 200, a stator 300, and a case 400. In particular, an automobile motor, a motor for a generator is required to be high-output, and the rotating electric machine 100 is also large-sized along with the high output.

[0040] The rotor 200 is constituted by a plurality of rotor cores and permanent magnets. The plurality of rotor cores are arranged in a rotation axis direction, and are inclined to each other (torque ripple is suppressed).

[0041] The stator 300 is constituted by a divided core and a coil wound on the core. The stator 300 is fixed by the thermal press fit of the outer periphery thereof to the inner periphery of the case 400.

[0042] Along with the large-sizing of the rotating electric machine 100, for example, in the case of being mounted on an electric automobile, the plate thickness of the case 400 is thickened in order for the case 400 to be able to withstand the vibration of the electric automobile. On the other hand, in order to improve productivity, the case 400 is formed by press working or draw working. Along with the thickening of the plate thickness thereof, the press working is sometimes preferred.

[0043] That is, the rotating electric machine 100 has the rotor 200, the stator 300, and the case 400, and the case 400 is a cylindrical shape, and the stator 300 is fixed from the outer periphery side.

[0044] Figure 2 FIG. 1 is a perspective view of the appearance of the rotating electrical machine 100 according to the present embodiment.

[0045] The housing 400 of the rotating electrical machine 100 is fixed to the stator 300 by shrink fit.

[0046] The housing 400 includes a cylindrical portion 410 that secures the stator 300 from the outer circumference. A flange (flat surface) 420 is formed at an axial end portion of the outer circumference of the housing 400. A lug (mounting surface) 430 is formed on a portion of the flange 420, serving as a mounting surface for a mating component (not shown). The flange 420 is formed at an axial end portion of the outer circumference of the housing 400 and extends toward the outer circumference of the housing 400.

[0047] Furthermore, the lug 430 is formed at an axial end portion of the outer peripheral surface of the housing 400 , and is partially extended from the flange 420 in the outer peripheral direction of the housing 400 .

[0048] Figure 3 FIG. 1 is a partial perspective view of the rotating electrical machine 100 according to the present embodiment.

[0049] The housing 400 is fixed to the stator 300 by shrink fit, and includes a cylindrical portion 410 , a flange 420 , and a lug 430 .

[0050] The flange 420 has a circumferentially extending recess 450 at an axial end portion of the outer circumferential surface of the housing 400. This improves the circularity of the housing 400 and suppresses the increase in surface pressure on the stator 300. The recess 450 preferably has a depth of 10% to 15% of the thickness of the flange 420. This improves the circularity of the housing 400.

[0051] In addition, the stator 300 with the housing 400 described in this embodiment has a cylindrical housing 400 that fixes the stator 300 from the outer peripheral side. The housing 400 is formed by a flat plate through stamping or stretching, and has a flange 420 extending in the outer peripheral direction on the axial end of the outer peripheral surface. The flange 420 has a plurality of recesses 450 extending in the circumferential direction.

[0052] Figure 4 FIG. 4 is a perspective view of the appearance of the casing 400 of this embodiment.

[0053] The housing 400 includes a cylindrical portion 410 , a flange 420 , and a plurality of (six in this embodiment) lugs 430 .

[0054] The lugs 430 include two types of lugs having different lengths in the circumferential direction of the housing 400 , and are formed so that the lugs 430 of the same type face each other with respect to the center of the housing 400 .

[0055] The flange 420 has a plurality of (eight in this embodiment) circumferentially extending recesses 450 at the axial end of the outer peripheral surface of the housing 400. This improves the circularity of the housing 400 and suppresses an increase in surface pressure on the stator 300.

[0056] The recesses 450 are formed substantially equidistantly in the circumferential direction of the housing 400. The recesses 450 are formed on the flange 420 where the lugs 430 are formed, and are also formed on the flange 420 where the lugs 430 are not formed.

[0057] In addition, the length of the recess 450 (the length of the recess 450 in the circumferential direction of the housing 400) can be the same, or it can be combined with the length of the lug 430 to lengthen the portion of the flange 420 of the longer lug 430 and shorten the portion of the flange 420 of the shorter lug 430.

[0058] That is, the recessed portions 450 are intermittently formed at a plurality of locations in the circumferential direction of the flange 420 .

[0059] Furthermore, a convex portion 460 is formed on the inner peripheral surface of the cylindrical portion 410 of the housing 400 in which the concave portion 450 is formed.

[0060] In addition, the stator 300 having the housing 400 described in this embodiment has a plurality of lugs 430 formed on the flange 420, recesses 450 are formed on the flange 420 having the lugs 430, and protrusions 460 are formed on the inner periphery of the housing 400 and on the opposite surface of the recesses 450.

[0061] Figure 5 FIG. 1 is a partial cross-sectional view of the rotating electrical machine 100 according to this embodiment.

[0062] In particular, Figure 5 The figure shows the positional relationship between the stator 300 and the protrusion 460 formed on the housing 400. The protrusion 460 is formed away from the grounding surface between the stator 300 and the housing 400. This ensures that the cylindrical portion 410 of the housing 400, which is grounded to the stator 300, maintains its circularity in the axial direction, thereby reducing the surface pressure exerted on the stator 300. Furthermore, the protrusion 460 is not a rectangular protrusion but a smooth projection.

[0063] That is, the convex portion 460 is formed on the inner circumference of the housing 400 and on the opposite surface where the concave portion 450 is formed. Thus, the convex portions 460 are also formed at substantially equal intervals in the circumferential direction of the housing 400.

[0064] Figure 6 This is an explanatory diagram showing the influence of the roundness of the housing on the magnetic characteristics of the stator (the relationship between the magnetic field intensity and the magnetic flux density) in this embodiment.

[0065] Depend on Figure 6As is apparent, if the roundness is improved, the magnetic flux density with respect to the magnetic field strength rises.

[0066] Figure 7 A diagram for explaining the influence of the roundness of the housing of the present embodiment on the magnetic characteristics (the relationship between the magnetic flux density and the iron loss) of the stator.

[0067] As is apparent, if the roundness is improved, the magnetic flux density with respect to the magnetic field strength rises. Figure 7 As is apparent, if the roundness is improved, the magnetic flux density with respect to the magnetic field strength rises.

[0068] That is, if the roundness is improved, the surface pressure generated on the stator 300 can be reduced, and the compressive stress acting on the stator 300 can be reduced. The magnetic characteristics are improved, and thus the output of the rotary electric machine is increased or the efficiency of the rotary electric machine is increased. In addition, the roundness indicates the deviation from the geometrically perfect circle, and the roundness "good" indicates the closer to the geometrically perfect circle.

[0069] Thus, in the present embodiment, the deterioration of the magnetic characteristics caused by the compressive stress can be suppressed, and a rotary electric machine having good motor performance can be provided.

[0070] Figures 8(a)-8(f) A perspective view of the first step to the sixth step of the manufacturing method of the housing 400 of the comparative example. In addition, in the upper view and the lower view, the upper view is a plan view, and the lower view is a sectional view. Figures 8(b)-8(f)

[0071] In order to improve the productivity, the housing 400 is manufactured from the rolled material after rolling in the order of the drawing process step by the stretching process step. Figures 8(a)-8(f)

[0072] As shown in Fig. 8(a), the rolled material (flat plate) 810 rolled in the rolling direction is finish-processed to a prescribed size by a plate-shaped material between rotating rolls.

[0073] As shown in Fig. 8(b), the blank 820 is punch-processed to a prescribed shape from the rolled material 810 by a press.

[0074] As shown in Fig. 8(c), the drawn material 830 is processed to a kettle shape from the blank 820 by the drawing process, and is composed of a bottom edge portion 831, a cylindrical portion 832 formed in the axial direction, and an outer peripheral portion 833 formed in the radial direction. The cylindrical portion 832 which becomes the main body portion 841 in the subsequent step is formed in good roundness by applying the drawing process by the first jig 891 which is stretched to a cylindrical shape.

[0075] ​​As shown in Figure 8(d), the cut piece 840 is formed into a generally cylindrical shape by cutting the base portion 831 and outer peripheral portion 833 of the drawn piece 830. Specifically, it comprises a main body 841 formed cylindrically in the axial direction, a flange 842 formed radially, and a mounting surface lug 843 formed by the flange 842. The root formed by the axial end of the outer peripheral surface of the main body 841 and the flange 842 is bent at an acute angle, forming a rounded portion during stamping.

[0076] As shown in FIG8(e), the lug plane extension workpiece 850 is punched by the third jig 893 as a base and the second jig 892 pressing from above. At this time, the second jig 892 presses the mounting surface lug 843.

[0077] As shown in FIG. 8( f ), through such steps, the housing 400 including the cylindrical portion 410 , the flange 420 , and the lug 430 is manufactured.

[0078] The rolled material 810 is generally known as a rolled material, and has different properties (anisotropy) in the rolling direction and in a direction at a predetermined angle relative to the rolling direction (e.g., 45° or 90°). This anisotropy affects the amount of springback after bending.

[0079] For this reason, even if all the lugs of the lug plane extending workpiece 850 shown in Figure 8(e) are stamped under the same conditions, the rebound amount of the housing 400 (final shape) shown in Figure 8(f) is different, which will also affect the roundness of the cylindrical portion 410 of the housing 400.

[0080] Furthermore, even when the main body 841 of the drawn part 830 shown in FIG8(c) is formed using the first jig 891, which has good roundness, the roundness of the main body 841 deteriorates due to the anisotropy of the rolled material and the difference in springback when the main body 841 is released from the first jig 891. Furthermore, the roundness is further deteriorated due to the extension of the workpiece 850 through the cutting piece 840 and the lug plane.

[0081] Figures 9(a)-9(f) 1 to 6 are explanatory diagrams showing the first to sixth steps of the method for manufacturing the housing 400 of this embodiment. Figures 9(b)-9(f) There are two figures, the upper figure is a top view and the lower figure is a cross-sectional view. Figures 9(a)-9(d) The first to fourth steps shown are Figures 8(a)-8(d) The first to fourth steps shown are the same steps, so their descriptions are omitted.

[0082] As shown in Figure 9(e), the tab flat-projection workpiece 850 is stamped and flattened using a third jig 893, which serves as a base, and a second jig 892, which presses from above. At this point, the second jig 892 presses the flange 842 at approximately equal intervals. Furthermore, this pressing creates concave portions and convex portions on the housing.

[0083] Specifically, a recess is formed in the rounded portion of the base formed by the axial end of the outer peripheral surface of the main body 841 and the flange 842. This recess corrects deformation caused by differences in springback due to anisotropy of the rolled material and suppresses deterioration in roundness.

[0084] Since the recessed portion is formed to extend circumferentially rather than axially, deformation caused by differences in springback is not corrected locally, achieving a sufficient effect in suppressing roundness degradation. By forming the recessed portion to extend circumferentially, correction is achieved globally, maintaining good roundness.

[0085] As shown in FIG. 9( f ), through such a process, the housing 400 having the cylindrical portion 410 , the flange 420 , and the lug 430 and having good roundness is manufactured.

[0086] In particular, as automotive rotating electrical machines increase in size with higher output, the retention force of the mating stator increases, and the required strength of the housing also increases, increasing the opportunity to use high-tensile steel sheets. Considering that high-tensile steel sheets have a greater amount of springback than ordinary steel sheets, and the impact of deterioration in roundness caused by springback is greater, the use of this method to suppress springback is effective.

[0087] This makes it possible to correct deformation caused by differences in springback due to anisotropy of the rolled material, and provide a housing with good roundness.

[0088] To ensure the flatness of the lugs, the surface with the lugs needs to be flattened. However, to improve roundness, it is preferable to perform stamping at approximately equal intervals, and it is also preferable to perform stamping on the flange without lugs. This ensures the flatness of the lugs and a well-rounded shape of the housing.

[0089] Therefore, even if a casing is thick and difficult to draw, the surface pressure generated on the stator can be made uniform by using a casing with good roundness, thereby providing a highly reliable rotating electrical machine.

[0090] The roundness of the housing also affects the roundness of the stator, which also affects the increase in magnetic noise. In addition, the air gap between the rotor and the stator needs to be considered based on the roundness of the stator. Therefore, in this embodiment, there is no need to set an unnecessary air gap, and a rotating electrical machine with good motor performance can be provided.

[0091] Example 2

[0092] Figure 10 FIG. 4 is a partial perspective view of a casing 400 according to another embodiment.

[0093] The housing 400 is formed with a flange 420 and a lug 430 , and recesses 451 are formed intermittently at substantially equal intervals in the circumferential direction at an axial end portion of an outer peripheral surface of the housing 400 .

[0094] That is, the recessed portions 451 are formed intermittently in the circumferential direction on the flange 420 where the lugs 430 are formed.

[0095] According to this embodiment, a housing with improved roundness can be provided, and a local increase in surface pressure generated on the stator can be suppressed.

[0096] In addition, the present invention is not limited to the above-described embodiment, and includes various modifications.

[0097] Explanation of symbols

[0098] 100 : Rotating electrical machine, 200 : Rotor, 300 : Stator, 400 : Housing, 410 : Cylindrical portion, 420 : Flange, 430 : Lug, 450 : Concave portion, 460 : Concave portion.

Claims

1. A rotating electrical machine, characterized in that: have: A rotor, a stator, and a cylindrical housing to which the stator is fixed from the outer circumference. The housing has a flange extending in the outer circumferential direction on the axial end of the outer circumferential surface, and a recess extending in the circumferential direction is formed on the rounded corner of the root formed by the axial end and the flange. Also having a plurality of lugs formed on the flange, The recess is formed on the flange where the lug is formed and the flange where the lug is not formed. A convex portion is provided on the inner periphery of the housing and on the opposite side of the surface where the concave portion is formed, wherein the convex portion is formed at the same time as the concave portion is formed. The concave portions and the convex portions are formed at substantially equal intervals in the circumferential direction of the housing.

2. The rotating electrical machine according to claim 1, wherein The recessed portions are formed intermittently at a plurality of locations in the circumferential direction of the flange.

3. The rotating electrical machine according to claim 1, wherein The protrusion is formed away from a ground contact surface between the stator and the housing.

4. A stator having a housing, characterized in that: The housing is a cylindrical housing that fixes the stator from the outer peripheral side. The housing is formed by stamping or stretching a flat plate, and has a flange extending in the circumferential direction on the axial end of the outer peripheral surface, and a plurality of recesses extending in the circumferential direction are formed on the rounded corner of the root formed by the axial end and the flange. At the same time as the recess is formed, a convex portion is formed on the inner peripheral portion of the housing and on the opposite side of the housing where the recess is formed. Also having a plurality of lugs formed on the flange, The recess is formed on the flange where the lug is formed and the flange where the lug is not formed. The concave portions and the convex portions are formed at substantially equal intervals in the circumferential direction of the housing.

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