Rotor yoke

Abstract

To improve the work efficiency of a reluctor forming work.SOLUTION: The present disclosure relates to a rotor yoke 10 of an outer rotor type power generator. The rotor yoke includes a yoke bottom plate portion 11, and a cylindrical yoke-side wall portion 12 that includes a plurality of reluctors 14 arranged separately in a circumferential direction and projecting radially outward, and that stands from an outer circumferential edge of the yoke bottom plate portion 11. A plurality of recesses 16 that are recessed radially outward so as to correspond to the plurality of reluctors 14, are formed on a radially inner side of the yoke-side wall portion 12 at a position where the plurality of reluctors 14 are arranged. The plurality of reluctors 14 have a reluctor group 15 in which two or more reluctors are regarded as one set. One side surface 16b and the other side surface 16c in the circumferential direction of the recess 16 that corresponds to the reluctor group 15, are formed into a parallel state in which both the surfaces are parallel with a first radial line L1 passing through the center position P in the circumferential direction of the reluctor group 15, or into a state in which one of the surfaces is separated away from the other surface toward the inside in the radial direction, compared to the parallel state.SELECTED DRAWING: Figure 5

Description

Technical Field

[0004]

[0001] The present disclosure relates to a rotor yoke to .

Background Art

[0002] Patent Document 1 discloses a magnet generator which is a rotating electric machine. The magnet generator is an outer rotor type generator used for a motorcycle, and includes a rotor fixed to the tip of the crankshaft of the engine and a stator fixed to the case of the engine. The rotor has a bottomed cylindrical rotor yoke. On the outer peripheral wall side of the peripheral wall of the rotor yoke, a plurality of reluctor (protrusions) for detecting the ignition timing of the engine and the like are integrally formed at equal intervals in the circumferential direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a rotor yoke having multiple recurctors (protrusions), such as the rotor of a rotating electric machine described in Patent Document 1, the recurctors are generally formed by press forming, pushing them out from the radially inner side of the rotor yoke to the outer side. When forming recurctors on a rotor yoke, press forming each recurctor one by one is time-consuming and inefficient, so it is conceivable to press form multiple recurctors simultaneously. However, the direction of extrusion of each recurctor radially outward from the center of the rotor yoke is different from that of the other, and the inner diameter of the rotor yoke is a limited space. Therefore, it is difficult to insert multiple punches with different extrusion directions (angles) from the center of the rotor yoke into the inner diameter of the rotor yoke, making it difficult to press form multiple recurctors simultaneously. For example, punches for simultaneously extruding two recurctors located directly opposite each other with respect to the center of the rotor yoke are prone to interference with each other, making it difficult to place them in the inner diameter of the rotor yoke.

[0005] Therefore, this disclosure provides a rotor yoke capable of improving the work efficiency of recurctor molding operations. of The purpose is to provide it. [Means for solving the problem]

[0006] To solve the above problems, a first aspect of the present invention is a rotor yoke for an outer rotor type rotating electric machine, comprising a yoke bottom plate portion and a cylindrical yoke side wall portion that rises from the outer peripheral edge of the yoke bottom plate portion and has a plurality of recurctors arranged at positions spaced apart from each other in the circumferential direction and protruding radially outward, wherein a plurality of recesses are formed on the radially inward side of the yoke side wall portion at the positions where the plurality of recurctors are arranged, recessing radially outward in correspondence with the plurality of recurctors, the plurality of recurctors have a group of two or more recurctors as a set, and one side and the other side in the circumferential direction of the recess corresponding to the group of recurctors are formed in a parallel state where both surfaces are parallel with respect to a first radial line passing through the circumferential center of the group of recurctors, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the parallel state.

[0007] A second aspect of the present invention is a rotor yoke according to the first aspect, wherein the recesses corresponding to the recurctor group are formed symmetrically with respect to the first radial line when viewed from the axial direction of the yoke side wall.

[0008] A third aspect of the present invention is a rotor yoke according to the first or second aspect, wherein the plurality of recesses include recesses that are formed asymmetrically with respect to a second radial line passing through the circumferential central position of each recess when viewed from the axial direction of the yoke side wall.

[0009] A fourth aspect of the present invention is a rotor yoke according to the first or second aspect, wherein a plurality of reluctor groups are provided, and the plurality of reluctor groups are arranged in a circumferential direction on the side wall of the yoke.

[0010] A fifth aspect of the present invention is a rotor yoke according to the first or second aspect, wherein the recurctor group comprises one or more one-side recurctors arranged on one side in the circumferential direction relative to the first radial line, and one or more other-side recurctors arranged on the other side in the circumferential direction relative to the first radial line, and other recurctors not included in the recurctor group are arranged between the one-side recurctors and the other-side recurctors of the recurctor group.

[0011] A sixth aspect of the present invention is a rotor yoke according to the fifth aspect, wherein a plurality of recurctor groups are provided, and the plurality of recurctors include a first adjacent group in which the recurctors on one side of the plurality of recurctor groups are adjacent to each other in the circumferential direction, and a second adjacent group in which the recurctors on the other side of the plurality of recurctor groups are adjacent to each other in the circumferential direction, and the first adjacent group and the second adjacent group are arranged alternately in the circumferential direction.

[0012] A seventh aspect of the present invention is a rotor yoke according to the first or second aspect, wherein the recurctor group comprises a central recurctor positioned in the center in the circumferential direction, one or more side recurctors positioned on one side of the central recurctor in the circumferential direction, and one or more other side recurctors positioned on the other side of the central recurctor in the circumferential direction, wherein the recesses corresponding to the side recurctors and the other side recurctors are formed asymmetrically with respect to a second radial line passing through the circumferential center of each recess when viewed from the axial direction of the yoke side wall, and the recess corresponding to the central recurctor is formed symmetrically with respect to the second radial line when viewed from the axial direction.

[0013] An eighth aspect of the present invention is a recurctor forming method for forming a plurality of recurctors on the cylindrical yoke side wall portion of the rotor yoke of an outer rotor type rotating electric machine, wherein the recurctors are spaced apart from each other in the circumferential direction and protrude radially outward, and the method includes an extrusion step in which the yoke side wall portion is positioned between a die corresponding to a group of recurctors, which consists of two or more recurctors as a set, and a punch corresponding to the group of recurctors, and the punch and the die are moved relative to each other along the radial direction passing through the circumferential center of the group of recurctors to push the group of recurctors radially outward.

[0014] A ninth aspect of the present invention is a recurctor molding method according to the eighth aspect, comprising a moving step of rotating the die and the punch and the rotor yoke relative to each other in the circumferential direction so that the region of the yoke side wall in which the recurctor has not been molded is positioned between the die and the punch, and repeating the moving step and the extrusion step in that order after the extrusion step until the number of unformed recurctors becomes smaller than the number of recurctors constituting the recurctor group.

[0015] A tenth aspect of the present invention is a recurctor molding method according to the ninth aspect, comprising a fractional processing step in which, after the extrusion step, if the number of unformed recurctors is smaller than the number of recurctors constituting the recurctor group, the die and the punch and the rotor yoke are rotated relative to each other in the circumferential direction so that the die and the punch straddle either of the already formed recurctors and the region where the recurctors have not been formed in the yoke side wall portion, and then the punch and the die are moved relative to each other along the radial direction passing through the circumferential center of the recurctor group to push the unformed recurctors radially outward.

[0016] An eleventh aspect of the present invention is a recurctor forming apparatus for forming a plurality of recurctors on the cylindrical yoke side wall of the rotor yoke of an outer rotor type rotating electric machine, the recurctors being spaced apart from each other in the circumferential direction and protruding radially outward, comprising: a die corresponding to a group of recurctors, each consisting of two or more recurctors; a punch positioned opposite the die and corresponding to the group of recurctors; and a drive unit that can move relative to the punch and the die so as to bring them closer together along the radial direction passing through the circumferential center of the group of recurctors.

[0017] A twelfth aspect of the present invention is a recurctor forming apparatus according to the eleventh aspect, wherein one circumferential side and the other side of the tip of the punch are formed in a parallel state where both surfaces are parallel with respect to a radial line passing through the central position of the circumferential recurctor group, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the parallel state. [Effects of the Invention]

[0018] According to this disclosure, the work efficiency of recurctor molding operations can be improved. [Brief explanation of the drawing]

[0019] [Figure 1] This is a cross-sectional view of a generator equipped with a rotor yoke according to one embodiment of the present invention. [Figure 2]It is a perspective view from the outside of the rotor yoke according to the first embodiment of the present invention. [Figure 3] It is a plan view from the outside of the rotor yoke. [Figure 4] It is a perspective view from the inside of the rotor yoke. [Figure 5] It is a cross-sectional view of the main part of the rotor yoke. [Figure 6] It is a plan view from the outside of the rotor yoke showing a modified example of one of the reluctor groups of the rotor yoke. [Figure 7] It is a cross-sectional view of the reluctor group of FIG. 6. [Figure 8] It is a plan view from the outside of the rotor yoke according to the second embodiment of the present invention. [Figure 9] It is a cross-sectional view of the main part of the rotor yoke. [Figure 10] It is an external view of a reluctor forming device according to an embodiment of the present invention, where (a) shows the state viewed from the side and (b) shows the b-b cross-section of (a). [Figure 11] It is an explanatory view showing a state where a reluctor group is being formed with a die and a punch. [Figure 12] It is an enlarged view of part XII of FIG. 11.

Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment of the present invention will be described based on the drawings.

[0021] FIG. 1 is a cross-sectional view of a generator 1 including a rotor yoke 10 according to an embodiment of the present invention. In each figure, CL indicates the rotation axis (axis center) of the rotor 3.

[0022] As shown in Figure 1, a rotor yoke 10 according to one embodiment of the present invention is used, for example, in an outer rotor type generator (rotating electric machine) 1. The generator 1 is a magnetotype generator and is used, for example, as an ACG (alternating current generator) for a motorcycle. The generator 1 comprises a rotor 3 fixed to the tip of the crankshaft 2 of an engine (not shown) and rotating together with the crankshaft 2, and a stator 5 fixed to the vehicle body side (for example, the engine case 4 side). In the following description, the direction along the rotation axis CL of the rotor 3 is called the axial direction, the direction perpendicular to the rotation axis CL is called the radial direction, and the direction along the rotation direction of the rotor 3 around the rotation axis CL is called the circumferential direction.

[0023] The rotor 3 has a bottomed cylindrical rotor yoke 10 and permanent magnets 6 fixed to the inner circumferential surface of the rotor yoke 10. Multiple permanent magnets 6 are provided circumferentially on the rotor yoke 10 such that different magnetic poles are arranged alternately in the circumferential direction. The stator 5 is positioned radially inside the permanent magnets 6 with a gap between it and the permanent magnets 6. As the rotor 3 rotates relative to the stator 5, an electric current is generated in the coil 5a of the stator 5. This allows the generator 1 to charge the battery and supply power to electrical components.

[0024] Figure 2 is an external perspective view of the rotor yoke 10 according to the first embodiment of the present invention. Figure 3 is an external plan view of the rotor yoke 10. Figure 4 is an internal perspective view of the rotor yoke 10. Figure 5 is an enlarged view of the main part of the rotor yoke 10.

[0025] As shown in Figures 2 to 5, the rotor yoke 10 according to this embodiment integrally comprises a disc-shaped yoke bottom plate portion 11 and a cylindrical yoke side wall portion 12 that rises from the outer peripheral edge of the yoke bottom plate portion 11.

[0026] The yoke bottom plate portion 11 is formed in a disc shape centered on the rotation axis CL of the rotor 3. An opening 13 for fixing the crankshaft 2 is formed in the center of the yoke bottom plate portion 11.

[0027] The yoke side wall portion 12 is formed in a cylindrical shape centered on the rotation axis CL of the rotor 3. The yoke side wall portion 12 has a plurality (22 in this embodiment) of retractors 14 for detecting the engine ignition timing by the pulsar coil 7 (see Figure 1). The plurality of retractors 14 are arranged at positions spaced apart from each other in the circumferential direction of the yoke side wall portion 12 (equally spaced (equally angled) in this embodiment) and protrude radially outward. In this embodiment, the center angle θ1 between adjacent retractors 14 is set to 15 degrees. In this embodiment, there are two consecutive regions X where no retractors 14 are provided. In these regions X, the spacing between the retractors 14 is different from other regions, and this region X is wider than the others. The pulsar coil 7 is positioned facing the yoke side wall portion 12 of the rotor yoke 10 from the radially outside.

[0028] Each recurctor 14 is formed by press molding, which pushes a portion of the yoke side wall 12 radially from the inside to the outside. That is, on the radially inside of the yoke side wall 12 where multiple recurctors 14 are arranged, multiple recesses 16 are formed that recess radially outward, corresponding to each recurctor 14. The multiple recesses 16 will be described later. In this embodiment, the multiple recurctors 14 are formed to be the same shape as each other. Each recurctor 14 has a radially outer upper surface 14a, circumferential end faces 14b, 14c on both sides, and axial end faces 14d, 14e on both sides, and is a symmetrical trapezoidal shape that tapers radially outward when viewed from the axial direction. The upper surface 14a of each recurctor 14 is rectangular in shape with sides extending in the circumferential and axial directions. The angle θ2 between the circumferential end faces 14b, 14c on both sides of each recurctor 14 is set to 15 degrees. In other words, in this embodiment, the angle θ2 between the end faces 14b and 14c on both sides in the circumferential direction of each recurctor 14 is set to the same angle as the center angle θ1 between adjacent recurctors 14. In this invention, "the recurctors 14 having the same shape" means that the shape is the same when viewed from the protruding side of the recurctor 14, and does not refer to whether the shape (shape of the recess 16) is the same when viewed from the back side (recessed side). In addition, in this embodiment, the shape of the recurctor 14 is trapezoidal when viewed from the axial direction, but it is not limited to this. For example, the shape of the recurctor 14 may have a curved surface at the corner between the end faces 14b and 14c on both sides in the circumferential direction and the outer circumferential surface of the yoke side wall portion 12 when viewed from the axial direction.

[0029] As shown in Figures 3 and 5, the plurality of recurctors 14 have a recurctor group 15, each consisting of two or more adjacent recurctors 14 as a set. The recurctor group 15 is a set of multiple recurctors 14 that are formed in one press when the recurctors 14 are press-formed. In this embodiment, the plurality of recurctors 14 have a plurality (11 sets) of recurctor groups 15, each consisting of two adjacent recurctors 14 as a set. The plurality of recurctor groups 15 are arranged in a circumferential direction on the yoke side wall portion 12. The center angle of the recurctor group 15 (the center angle between a recurctor 14 located at one end in the circumferential direction and a recurctor 14 located at the other end) is less than 180 degrees. In this embodiment, since the recurctor group 15 is composed of two adjacent recurctors 14, the center angle θ1 of the recurctor group 15 is the center angle θ1 between the two recurctors 14, which is 15 degrees. Furthermore, two adjacent recurators 14 that straddle a region X in the yoke side wall 12 where no recurators 14 are provided do not constitute the same group of recurators 15.

[0030] Each recurctor group 15 has one or more recurctors (one-side recurctors) 14A positioned on one side in the circumferential direction (for example, the left side in Figure 5) of a radial line (the dashed line L1 shown in Figure 5; hereinafter referred to as the "first radial line L1") passing through the central position P in the circumferential direction of the recurctor group 15 (hereinafter simply referred to as the "central position P"), and one or more recurctors (other-side recurctors) 14B positioned on the other side in the circumferential direction (for example, the right side in Figure 5) of the first radial line L1. In this embodiment, since the recurctor group 15 is composed of two recurctors 14, each recurctor group 15 has one recurctor 14A and one recurctor 14B. One end face 14b of retractor 14A, located at one end of the retractor group 15 in the circumferential direction, and the other end face 14c of retractor 14B, located at the other end of the retractor group 15 in the circumferential direction, are provided parallel to the first radial line L1 when viewed from the axial direction (as shown in Figure 5). The dashed line L2 in Figure 5 represents the extension line L2 of one end face 14b of retractor 14A, and the dashed line L3 represents the extension line L3 of the other end face 14c of retractor 14B.

[0031] The central position P of the recurctor group 15 refers to the circumferential center between one end face 14b of recurctor 14A, which is located at one end in the circumferential direction, and the other end face 14c of recurctor 14B, which is located at the other end in the circumferential direction, when viewed from the axial direction. In this embodiment, one end face 14b of recurctor 14A and the other end face 14c of recurctor 14B are provided parallel to the first radial line L1, but this is not limited to this, and it is sufficient that they are not closer to the first radial line L1 as they move radially inward. For example, one end face 14b of recurctor 14A and the other end face 14c of recurctor 14B may be inclined so that they are further apart as they move radially inward with respect to the first radial line L1. However, from the viewpoint of clarifying the pulse signal of the pulse coil 7, it is preferable to provide one end face 14b of the retractor 14A and the other end face 14c of the retractor 14B parallel to the first radial line L1, as in this embodiment, in order to reduce the angle of the edge portion between the upper surface 14a and both end faces 14b and 14c of the retractor 144.

[0032] As shown in Figure 5, the multiple recesses 16 are recesses formed during press molding in which multiple recurators 14 are pushed out from the radial inside to the outside, and are provided corresponding to each recurator 14. The recess 16 has a radially outer bottom surface 16a, circumferential end surfaces 16b and 16c on both sides, and axial end surfaces (not shown) on both sides. In Figure 5, the dashed line L4 represents the extension line L4 of one side surface 16b of the recess 16, and the dashed line L5 represents the extension line L5 of the other side surface 16c of the recess 16.

[0033] On the radially inner side of the recurctor group 15, a recess 16 (a recess 16 corresponding to the recurctor group 15) corresponding to the recurctor 14 included in the recurctor group 15 is provided. In this embodiment, on the radially inner side of the recurctor group 15, recesses 16A and 16B corresponding to the recurctors 14A and 14B included in the recurctor group 15 are provided. In this embodiment, both the circumferential side surface 16b and the other side surface 16c of the recess 16 corresponding to the recurctor group 15 are formed in a state parallel to the first radial line L1 (hereinafter referred to as the "parallel state"). The recesses 16A and 16B corresponding to the recurctor group 15 are symmetrical with respect to the first radial line L1 when viewed from the axial direction (as shown in Figure 5). Furthermore, each of the recesses 16A and 16B corresponding to the recurctor group 15 is formed asymmetrically with respect to a radial line (the dashed line L6 shown in Figure 5; hereinafter referred to as the "second radial line L6") passing through the circumferential center of each recess 16 when viewed from the axial direction. That is, the plurality of recesses 16 provided in the yoke side wall portion 12 include recesses (recesses 16A, 16B) that are formed asymmetrically with respect to the second radial line L6 of each recess 16 when viewed from the axial direction of the yoke side wall portion 12. In this embodiment, both the circumferential side surface 16b and the other side surface 16c of the recess 16 corresponding to the recurctor group 15 are in the parallel state described above, but this is not limited to this, and at least one of the side surfaces 16b and the other side surface 16c may be spaced further apart from the other surface as it moves radially inward relative to the parallel state described above.

[0034] In the rotor yoke 10 configured as described above, both the circumferential surfaces of one side 16b and the other side 16c of the recess 16 corresponding to the recurctor group 15 are formed in the parallel state (parallel to the first radial line L1). Alternatively, at least one of the surfaces of the one side 16b and the other side 16c is formed in such a state that it is spaced further apart from the other surface as it moves radially inward relative to the parallel state. Therefore, when press-forming the recurctor 14, after forming the recurctor group 15 with a single press, the punch on the radially inner side of the yoke side wall 12 (the punch that pushes out the recurctor 14) can be easily removed along the radial direction (first radial line L1) passing through the central position P.

[0035] In this way, each punch corresponding to a plurality of recurctors 14 can be moved relative to the die along the same direction (first radial line L1). Unlike when each punch is moved in a different direction (angle), the mechanism for moving each punch can be standardized, and the structure of the punch side (the radially inner side of the yoke side wall 12) can be simplified. As a result, punches corresponding to a plurality of recurctors 14 can be arranged in the limited space of the inner diameter of the rotor yoke 10, and a plurality of recurctors 14 (recurctor group 15) can be formed in a single press.

[0036] Therefore, according to this embodiment, a group of recurctors 15 including two or more recurctors 14 can be formed by a single press. This is different from the case where each recurctor 14 is formed individually, and thus improves the efficiency of the recurctor forming process.

[0037] Furthermore, one end face 14b of retractor 14A and the other end face 14c of retractor 14B of retractor group 15 are provided parallel to the first radial line L1 or spaced further apart towards the radially inward direction. Therefore, when press-forming the retractor 14, after forming the retractor group 15 in a single press, the die (mold) on the radially outer side of the yoke side wall portion 12 can be easily removed along the first radial line L1.

[0038] Furthermore, since the recurctor group 15 can be pushed out to one side in the radial direction passing through the central position P (the upper side in Figure 5), deformation of the rotor yoke 10 can be suppressed, unlike, for example, the case where two recurctors 14 located directly opposite the center of the rotor yoke 10 are pushed out simultaneously.

[0039] Furthermore, the retractor 14 has a trapezoidal shape that tapers outward in the radial direction when viewed from the axial direction, with the base side (inward in the radial direction) of the retractor 14 being wider. This makes it possible to suppress material breakage at the yoke sidewall portion 12 at the base side of both end faces 14b, 14c of each retractor 14 during press forming.

[0040] In this embodiment, multiple recurctor groups 15 are provided, but the system is not limited to this; at least one recurctor group 15 is sufficient. By providing at least one recurctor group 15, the work efficiency of the recurctor molding process can be improved compared to the case where all recurctors 14 are molded one by one.

[0041] Furthermore, in this embodiment, the die can be removed along the first radial line L1 by providing one end face 14b of retractor 14A and the other end face 14c of retractor 14B of the retractor group 15 so as to be parallel to the first radial line L1 or spaced further apart towards the radially inward line L1, but the embodiment is not limited to this. For example, if two dies are provided corresponding to each retractor 14A and 14B of the retractor group 15, and each die is made movable along the second radial line L6 of each retractor 14A and 14B, then the one end face 14b and the other end face 14c of retractor 14 only need to be shaped in a way that allows each die to be removed.

[0042] Furthermore, in this embodiment, the recurctor group 15 is defined as a group of two adjacent recurctors 14 (recurctors 14A and 14B), but the number of recurctors 14 constituting the recurctor group 15 (number of recurctors) is not limited to this. As will be described later, the recurctor group 15 may be defined as a group of three adjacent recurctors 14, or as a group of four or more adjacent recurctors 14.

[0043] Figure 6 is an external plan view of the rotor yoke 10 showing one modified example of the recurctor group 15 of the rotor yoke 10. Figure 7 is a cross-sectional view of the recurctor group 15 of Figure 6.

[0044] For example, as shown in Figures 6 and 7, the recurctor group 15 may be a group of recurctors 14 consisting of an odd number (e.g., three) of adjacent recurctors 14. The recurctor group 15 includes a recurctor (central recurctor) 14C positioned in the center in the circumferential direction, one or more recurctors (side recurctors) 14A positioned on one side of the recurctor 14C in the circumferential direction, and one or more recurctors (other side recurctors) 14B positioned on the other side of the recurctor 14C in the circumferential direction. Even in this case, one side 16b and the other side 16c of the recesses 16A, 16B, and 16C corresponding to the recurctor group 15 are formed in a parallel state where both surfaces are parallel with respect to the first radial line L1 of the recurctor group 15, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the above parallel state. Furthermore, the recesses 16A, 16B, and 16C corresponding to the recurctor group 15 are formed symmetrically with respect to the first radial line L1 when viewed from the axial direction of the yoke side wall portion 12 (as shown in Figure 7). In addition, the multiple recesses 16 include recesses (recesses 16A, 16B) that are formed asymmetrically with respect to the second radial line L6 of each recess 16 when viewed from the axial direction of the yoke side wall portion 12. In this case, the recess 16C of the recurctor 14C located in the center in the circumferential direction is formed symmetrically with respect to the second radial line L6. Note that multiple recurctors (one-side recurctors) 14A, which are positioned on one side of the recurctor 14C in the circumferential direction, and multiple recurctors (other-side recurctors) 14B, which are positioned on the other side, may also be provided.

[0045] Next, a second embodiment of the present invention will be described with reference to the drawings. The rotor yoke 101 of this embodiment differs in that the recurctor group 15 includes recurctors 14 that are not adjacent to each other. Components similar to those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0046] Figure 8 is an external plan view of the rotor yoke 101 according to a second embodiment of the present invention. Figure 9 is a cross-sectional view of the main part of the rotor yoke 101.

[0047] As shown in Figures 8 and 9, the rotor yoke 101 has a plurality of recurctors 14, each consisting of a group of multiple recurctors 15 arranged to sandwich n (an integer of 1 or more) recurctors 14. In this embodiment, a plurality of recurctor groups 15 are provided, each consisting of a group of two recurctors 14A and 14B arranged to sandwich one recurctor 14 (n=1).

[0048] The recurctor group 15 includes one or more recurctors (one-side recurctors) 14A positioned on one side in the circumferential direction of a first radial line L1 passing through the central position P in the circumferential direction of the recurctor group 15, and one or more recurctors (other-side recurctors) 14B positioned on the other side in the circumferential direction of the first radial line L1. Between recurctors 14A and recurctors 14B, other recurctors 14A' (recurctors 14A' included in the other recurctor group 15') that are not included in the recurctor group 15 are positioned. The number of recurctors 14 included in recurctors 14A positioned on one side in the circumferential direction of the first radial line L1 and recurctors 14B positioned on the other side is set to be less than or equal to the number of recurctors 14 positioned between them (n).

[0049] Both the circumferential surface 16b and the other surface 16c of the recesses 16 (recesses 16A, 16B) corresponding to the recurctor group 15 are formed parallel to the first radial line L1. The recesses 16A and 16B corresponding to the recurctor group 15 are symmetrical with respect to the first radial line L1 when viewed from the axial direction (as shown in Figure 9). Furthermore, each of the recesses 16A and 16B corresponding to the recurctor group 15 is formed asymmetrically with respect to the second radial line L6 when viewed from the axial direction. In other words, the plurality of recesses 16 provided in the yoke side wall 12 include recesses (recesses 16A, 16B) that are formed asymmetrically with respect to the second radial line L6 of each recess 16 when viewed from the axial direction of the yoke side wall 12. In this embodiment, both the circumferential side surface 16b and the other side surface 16c of the recess 16 corresponding to the recurctor group 15 are in the parallel state described above. However, the embodiment is not limited to this, and at least one of the side surfaces 16b and the other side surface 16c may be spaced further apart from the other surface as it moves radially inward relative to the parallel state described above.

[0050] The recurctor 14A' between recurctor 14A and recurctor 14B of recurctor group 15 is included in another recurctor group 15' which is different from the above recurctor group 15. The recesses 16A' and 16B' corresponding to the other recurctor group 15' have the same configuration as the recess 16 corresponding to the above recurctor group 15, with reference to the first radial line L1' passing through the circumferential central position P' of the recurctor group 15'.

[0051] As shown in Figure 8, the multiple recurators 14 provided on the yoke side wall portion 12 include a first adjacent group 17A in which recurators 14A, 14A on one side in the circumferential direction of multiple recurator groups 15, 15' are adjacent to each other in the circumferential direction, and a second adjacent group 17B in which recurators 14B, 14B' on the other side in the circumferential direction are adjacent to each other in the circumferential direction. The first adjacent group 17A and the second adjacent group 17B are arranged alternately in the circumferential direction. The first adjacent group 17A includes n+1 sets of recurators 14A from recurator groups 15, and the second adjacent group 17B includes n+1 sets of recurators 14B from recurator groups 15. In this embodiment, the first adjacent group 17A includes 2 sets (n+1 sets) of recurators 14A from recurator groups 15, and the second adjacent group 17B includes 2 sets (n+1 sets) of recurators 14B from recurator groups 15.

[0052] In this embodiment, a recurctor group 15 is provided with two recurctors 14A and 14B on each side (one on each side). However, the invention is not limited to this configuration, and a recurctor group 15 may be provided with multiple recurctors 14A and 14B on each side.

[0053] Next, a recurctor molding apparatus 20 according to one embodiment of the present invention will be described based on the drawings.

[0054] Figure 10 is an external view of a recurctor molding apparatus according to one embodiment of the present invention, where (a) shows a view from the side and (b) shows a cross-section of (a) bb. Figure 11 is an explanatory diagram showing the state in which a group of recurctors is being molded by a die and a punch. Figure 12 is an enlarged view of part XII in Figure 11.

[0055] The recurctor forming apparatus 20 according to this embodiment is a press forming apparatus that forms a plurality of recurctors 14 on the cylindrical yoke side wall portion 12 of the rotor yoke 10 of an outer rotor type generator 1, spaced apart from each other in the circumferential direction and protruding radially outward. The recurctor forming apparatus 20 of this embodiment forms a plurality of recurctors 14 of the same shape, spaced apart from each other at equal intervals in the circumferential direction, on the yoke side wall portion 12.

[0056] As shown in Figure 10, the recurctor molding apparatus 20 according to this embodiment forms a group of recurctors 15, composed of two or more recurctors 14, onto the yoke side wall portion 12 in a single extrusion process. The recurctor molding apparatus 20 includes a die 21 that serves as the mold for a set of recurctors 15, a punch 22 that extrudes the set of recurctors 15, and a drive unit 23 that can move relative to the die 21 and the punch 22 to bring them close together. In addition to these, the recurctor molding apparatus 20 also includes an upper die set 24 that serves as the upper base, a lower die set 25 that serves as the lower base, a plurality of guide posts 26 that support the upper die set 24 and the lower die set 25 so that they can move relative to each other in a predetermined direction (up and down in this embodiment), and a pressing member 27 that is positioned below the die 21 and presses against the yoke side wall portion 12 during pressing. In the following description of the recurctor molding apparatus 20, the axial direction, radial direction, and direction correspond to the axial direction, radial direction, and direction of the rotor yoke 10 when it is set in the recurctor molding apparatus 20 (hereinafter referred to as the "set state").

[0057] The upper surface of the retaining member 27 is formed in an arc shape so that it can contact the yoke side wall portion 12 of the rotor yoke 10 from the radially inner side. When forming the recurctor 14, the rotor yoke 10 is set in the recurctor forming apparatus 20 with the inner circumferential surface of the yoke side wall portion 12 in contact with the arc-shaped upper surface of the retaining member 27 (see Figure 10(b)).

[0058] As shown in Figures 10 to 12, the die 21 of this embodiment is positioned radially outward (above) the yoke side wall portion 12 of the rotor yoke 10 in the set state and is supported by the upper die set 24. The die 21 has an arc-shaped lower surface 28 formed to make surface contact with the outer circumferential surface of the yoke side wall portion 12 when the recurctor molding apparatus 20 is driven, and a plurality of concave portions 29 that are recessed upward from the lower surface 28.

[0059] The lower surface 28 of the die 21 is formed in an arc shape such that the center in the circumferential direction bulges upward. When viewed from the axial direction, a virtual line (dotted line L1 shown in Figure 11) passing through the uppermost part of the circumferential center of the arc-shaped lower surface 28 of the die 21 (approximately the same position as the central position P of the recurctor group 15 shown in Figure 11) and the center of the rotor yoke 10 in the set state (rotation axis CL) extends in the vertical direction. This virtual line coincides with the first radial line L1 passing through the circumferential central position P of the recurctor group 15.

[0060] The multiple recessed portions 29 are provided symmetrically on the left and right sides of the uppermost portion (circumferential central portion) of the arc-shaped lower surface 28 of the die 21, when viewed from the axial direction. The number of recessed portions 29 is the same as the number of retractors 14 that make up a set of retractor groups 15. That is, the multiple recessed portions 29 are provided so as to correspond to a set of retractor groups 15. In this embodiment, since a set of retractor groups 15 is made up of two retractors 14 (retractor 14A and retractor 14B), the die 21 is provided with two recessed portions 29 (recessed portion 29A and recessed portion 29B). The center angle between the two recessed portions 29 is 15 degrees, the same as the center angle θ1 between retractor 14A and retractor 14B.

[0061] Each concave portion 29 of the die 21 has a bottom surface 29a, circumferential end surfaces 29b and 29c on both sides, and axial end surfaces (not shown) on both sides, and is a symmetrical trapezoidal shape that tapers radially outward when viewed from the axial direction, corresponding to the shape of the recurctor 14. In this embodiment, the bottom surface 29a of the concave portion 29 is formed by the lower surface of the spring pad 30 (see Figure 10(b)) which is located on the radially outer side (upper side in this embodiment) of the concave portion 29. The angle between the circumferential end surfaces 29b and 29c of each concave portion 29 is set to 15 degrees, the same as the angle θ2 between the circumferential end surfaces 14b and 14c of the recurctor 14. That is, in this embodiment, the angle between the circumferential end surfaces 29b and 29c of each concave portion 29 is set to the same angle as the center angle between two adjacent concave portions 29. Note that, for the sake of clarity, the spring pad 30 is not shown in Figures 11 and 12.

[0062] Of the multiple concave portions 29 of the die 21, the one end face 29b of the concave portion 29 located at one end in the circumferential direction and the other end face 29c of the concave portion 29 located at the other end in the circumferential direction are provided parallel to each other. In this embodiment, the one end face 29b of the concave portion 29A on one side in the circumferential direction (for example, the left side in Figure 11) and the other end face 29c of the concave portion 29B on the other side in the circumferential direction (for example, the right side in Figure 11) are provided parallel to each other along the vertical direction. That is, the one end face 29b of the concave portion 29A and the other end face 29c of the concave portion 29B are provided parallel to the dashed line (the dashed line L1 shown in Figures 11 and 12) when viewed from the axial direction.

[0063] The punch 22 has the function of pushing out the recurctor 14 from the yoke side wall 12 of the rotor yoke 10 and is supported by the lower die set 25 so as to be movable relative to the die 21 in the vertical direction. The same number of punches 22 are provided as the number of recurctors 14 that make up a set of recurctor groups 15. That is, the punches 22 are provided so as to correspond to a set of recurctor groups 15. In this embodiment, each punch 22 is formed in the shape of a rod that extends linearly in the vertical direction. Each punch 22 is supported by the lower die set 25 in a state in which it does not move relative to one another. The tip surface of the punch 22 (the upper end surface in this embodiment) is formed in the shape of a rectangle and is positioned to face the plurality of concave portions 29 of the die 21 from below. In the set state, the punch 22 is located radially inside the yoke side wall 12 of the rotor yoke 10. Note that the punch 22 may be formed by integrating a plurality of separately formed punches 22, or it may be formed from a single member.

[0064] One circumferential side surface 22a and the other side surface 22b of the tip (upper end) of the punch 22 are formed in a parallel state where both surfaces are parallel to the first radial line L1 of the recurctor group 15, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the above parallel state. In this embodiment, both one circumferential side surface 22a and the other side surface 22b of the tip of the punch 22 are formed in a state parallel to the first radial line L1 of the recurctor group 15. Note that the dashed line L4 in Figure 12 represents the extension line L4 of one side surface 22a of the tip of the punch 22, and the dashed line L5 represents the extension line L5 of the other side surface 22b of the tip of the punch 22.

[0065] The drive unit 23 moves the punch 22 and die 21 relative to each other along the first radial line L1 of the recurctor group 15, as shown by the white arrows in Figure 11. The drive unit 23 can move the punch 22 and die 21 relative to each other so as to switch between a separated state and a close-up state. The drive unit 23 has a punch moving mechanism 23a that moves the punch 22 along the first radial line L1. The punch moving mechanism 23a is positioned radially inward of the yoke side wall portion 12 of the rotor yoke 10 in the set state. The drive unit 23 may move the punch 22 and die 21 relative to each other by converting rotational motion, such as that of an electric motor, into linear motion, or by using hydraulics or the like. The relative movement of the punch 22 and die 21 may be performed by moving the other while one is fixed, or by moving both.

[0066] In the recurctor forming apparatus 20 configured as described above, the drive unit 23 moves the punch 22 and the die 21 relative to each other along a first radial line L1 that passes through the central position P in the circumferential direction of the recurctor group 15. In this way, each punch 22 that forms multiple recurctors 14 is moved relative to the die 21 along the same direction (first radial line L1), so unlike when each punch 22 is moved in different directions, the mechanism for moving each punch 22 (punch moving mechanism 23a) can be made common, simplifying the structure. As a result, the punches 22 that form multiple recurctors 14 can be arranged in the inner diameter portion of the rotor yoke 10, which is a limited space, and the recurctor group 15 can be formed in a single press.

[0067] Furthermore, one side surface 22a and the other side surface 22b of the tip (upper end) of the punch 22 are formed in a parallel state where both surfaces are parallel to the first radial line L1 of the recurctor group 15, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the above parallel state. For this reason, when press forming the recurctor 14, after forming the recurctor group 15 with a single press, the punch 22 can be easily removed along the first radial line L1.

[0068] Furthermore, of the multiple concave portions 29 of the die 21, the one end face 29b of the concave portion 29 located at one end in the circumferential direction and the other end face 29c of the concave portion 29 located at the other end in the circumferential direction are arranged to be parallel to the first radial line L1 when viewed from the axial direction, or to be spaced further apart towards the radially inward direction. Therefore, when press-forming the recurctor 14, after forming the recurctor group 15 with a single press, the die 21 can be easily removed along the first radial line L1.

[0069] Thus, according to this embodiment, a group of recurctors 15 including two or more recurctors 14 can be formed by pressing in a single step. This improves the efficiency of the recurctor forming process compared to forming the recurctors one by one.

[0070] Furthermore, since the recurctor group 15 can be pushed out to one side of the first radial line L1 (the upper side in Figure 11), deformation of the rotor yoke 10 can be suppressed, unlike, for example, the case where two recurctors 14 located directly opposite the center of the rotor yoke 10 are pushed out simultaneously.

[0071] In this embodiment, the die 21 is provided as a die 21 having a plurality of concave portions 29 corresponding to the recurctor group 15, but it is not limited to this, and a plurality of dies 21 corresponding to each individual recurctor 14 constituting the recurctor group 15 may be provided.

[0072] Next, a recurctor molding method relating to one embodiment of the present invention will be described.

[0073] The recurctor forming method according to this embodiment is a method for forming a plurality of recurctors 14 on the cylindrical yoke side wall portion 12 of the rotor yoke 10 of an outer rotor type generator 1, which are spaced apart from each other in the circumferential direction and protruding radially outward. In this embodiment, the case in which a plurality of recurctors 14 are formed on the yoke side wall portion 12 of the rotor yoke 10 using the recurctor forming apparatus 20 according to the above embodiment will be described. When forming a plurality of recurctors 14 on the yoke side wall portion 12 of the rotor yoke 10, the rotor yoke 10 without the plurality of recurctors 14 is formed in advance.

[0074] First, the yoke side wall portion 12 of the rotor yoke 10 is positioned between the die 21, which corresponds to a group of retractors 15 consisting of two or more adjacent retractors 14 from among a plurality of retractors 14, and the punch 22, which corresponds to the group of retractors 15 (preparation step). Specifically, the rotor yoke 10 is set in the retractor forming apparatus 20 with the punch 22 and die 21 spaced apart from each other.

[0075] Next, with the yoke side wall portion 12 positioned between the die 21 and the punch 22, the punch 22 and the die 21 are moved relative to each other along the first radial line L1 of the recurctor group 15, thereby pushing the recurctor group 15 radially outward (extrusion process). Specifically, the drive unit 23 of the recurctor molding apparatus 20 is activated to bring the punch 22 and the die 21 closer together along the first radial line L1. When the die 21 is in contact with the outer circumferential surface of the yoke side wall portion 12 and the punch 22 is in contact with the inner circumferential surface of the yoke side wall portion 12, and the punch 22 and the die 21 move even closer together, the punch 22 pushes the recurctor group 15 radially outward along the first radial line L1 of the yoke side wall portion 12. This makes it possible to form a recurctor group 15 containing two or more recurctors 14 in a single press (in the same process). Furthermore, pushing the recurctor group 15 along the first radial line L1 means applying a load along the first radial line L1 to a predetermined position on the yoke side wall portion 12 to push out the recurctor group 15.

[0076] Furthermore, after the extrusion process described above, if predetermined conditions are met, the die 21 and punch 22 and the rotor yoke 10 may be rotated relative to each other in the circumferential direction so that the region of the yoke side wall 12 in which the recurctor 14 has not yet been formed (the region in which the recurctor 14 will be formed next) is positioned between the die 21 and the punch 22. (Moving process). For example, the rotor yoke 10 may be rotated relative to the die 21 and the punch 22.

[0077] The above predetermined condition may also be that the number of unformed recurators 14 is equal to or greater than the number of recurators 14 constituting the recurator group 15. After the extrusion process, the above moving process and the extrusion process may be repeated in that order until the number of unformed recurators 14 becomes smaller than the number of recurators 14 constituting the recurator group 15. Note that the unformed recurators 14 refer to the recurators 14 that have not yet been formed out of the number of recurators 14 to be formed on the yoke side wall portion 12 (the number of recurators 14 to be formed; in this embodiment, 22).

[0078] Furthermore, if the above predetermined conditions are not met after the extrusion process, the remaining unformed recurctors 14 may be molded individually one by one. For example, the rotor yoke 10 may be removed from the recurctor molding apparatus 20, and the remaining unformed recurctors 14 may be molded individually one by one using another apparatus. The above predetermined conditions are not met when the number of unformed recurctors 14 is less than the number of recurctors 14 that make up the recurctor group 15.

[0079] Alternatively, if the above predetermined conditions are not met after the extrusion process, the die 21 and punch 22 and the rotor yoke 10 may be rotated relative to each other in the circumferential direction so that the die 21 and punch 22 straddle either an already formed recurctor 14 in the yoke side wall portion 12 or an area where no recurctor 14 has been formed. Then, the punch 22 and die 21 may be moved relative to each other along the first radial line L1 of the recurctor group 15 to push the unformed recurctors 14 radially outward (rounding process). At this time, the recurctors 14 that have already been formed (recurctors 14 that are positioned so that the die 21 and punch 22 straddle each other) will be pushed out again.

[0080] In the above recurctor forming method, with the yoke side wall portion 12 positioned between the die 21 and the punch 22, the punch 22 and the die 21 are moved relative to each other along the first radial line L1 of the recurctor group 15, thereby pushing the recurctor group 15 radially outward (extrusion process). In this way, since the recurctor group 15 is pushed out from the radial inside of the yoke side wall portion 12 along the same direction (first radial line L1), unlike when the recurctor group 15 is pushed out along different directions (directions that cause each recurctor 14 to protrude), the mechanism for moving each punch 22 can be standardized, simplifying the structure. As a result, each punch 22 can be positioned in the inner diameter portion of the rotor yoke 10, which is a limited space, and the recurctor group 15 can be formed in a single press.

[0081] Thus, according to this embodiment, by arranging multiple punches 22 in the inner diameter portion of the rotor yoke 10, which is a limited space, a group of recurctors 15 including two or more recurctors 14 can be formed in a single press. This improves the work efficiency of the recurctor forming operation compared to forming the recurctors 14 one by one.

[0082] Furthermore, after the extrusion process, the moving process and the extrusion process are repeated in that order until the number of unformed recurators 14 becomes smaller than the number of recurators 14 constituting the recurator group 15, thereby enabling efficient molding of the multiple recurators 14 to be provided on the yoke side wall portion 12.

[0083] Furthermore, if, after the extrusion process, the number of unformed recurators 14 is smaller than the number of recurators 14 constituting the recurator group 15, the above fractional processing step can be performed to allow multiple recurators 14 to be provided on the yoke side wall portion 12 to be molded to completion using a single recurator molding device 20.

[0084] In this embodiment, multiple recurators 14 were formed using the recurator forming apparatus 20 according to the above embodiment, but the invention is not limited to this, and multiple recurators 14 may be formed using an apparatus with other configurations as long as it includes the first step and the second step described above.

[0085] Furthermore, the order in which the multiple recurctor groups 15 are formed is not particularly limited. For example, they may be formed sequentially from one side to the other in the circumferential direction of the yoke sidewall portion 12, or they may be formed in an order such that the middle portion in the circumferential direction of the yoke sidewall portion 12 is left to form last.

[0086] Furthermore, although the generator 1 in the above embodiment is an outer rotor type rotating electric machine, it is not limited to this, and the outer rotor type rotating electric machine may be, for example, a motor.

[0087] Although the present invention has been described above based on the above embodiments, the present invention is not limited to the contents of the above embodiments, and can naturally be modified as appropriate without departing from the present invention. In other words, all other embodiments, examples, and operational techniques made by those skilled in the art based on these embodiments are of course included in the scope of the present invention. [Explanation of symbols]

[0088] 1: Generator (rotating electric machine) 10: Rotor York 11: Yoke base plate 12: York side wall 14: Relacta 14A: Recurctor (single-sided recurctor) 14B: Recurctor (other-side recurctor) 14C: Recurctor (Central recurctor) 15: Recurctor group 16: Recess 16b: One side of the recess 16c: Other side of the recess 17A: First neighboring group 17B: Second Neighboring Group 20: Recurctor molding machine 21: Die 22: Punch 22a: One side of the tip of the punch 22b: Other side of the punch tip 23: Drive unit

Claims

1. This is a rotor yoke for an outer rotor type rotating electric machine, Yoke bottom plate and It comprises a plurality of recurvers arranged at circumferentially spaced apart from each other and protruding radially outward, and a cylindrical yoke side wall portion rising from the outer peripheral edge of the yoke bottom plate portion, On the radially inward side of the yoke side wall where the plurality of recurvers are arranged, a plurality of recesses are formed that are recessed radially outward in correspondence with the plurality of recurvers. The aforementioned plurality of recurators have a group of recurators, each consisting of two or more recurators as a set. The circumferential surfaces of one and the other of the recesses corresponding to the recurctor group are formed in a parallel state, where both surfaces are parallel with respect to a first radial line passing through the circumferential central position of the recurctor group, or in a state where at least one surface is spaced further apart from the other surface as it moves radially inward from the parallel state. The recesses corresponding to the recurctor group are formed symmetrically with respect to the first radial line when viewed from the axial direction of the yoke side wall. The plurality of recesses include recesses that are formed asymmetrically with respect to a second radial line passing through the circumferential central position of each recess when viewed from the axial direction of the yoke side wall. A rotor yoke characterized by the following features.

2. Multiple recurctor groups are provided, The plurality of recurctor groups are arranged in a circumferential direction on the yoke side wall. The rotor yoke according to feature 1.

3. The recurctor group comprises one or more one-side recurctors positioned on one side in the circumferential direction relative to the first radial line, and one or more other-side recurctors positioned on the other side in the circumferential direction relative to the first radial line. Between the one-sided recurctor and the other-sided recurctor of the recurctor group, other recurctors not included in the recurctor group are arranged. The rotor yoke according to feature 1.

4. Multiple recurctor groups are provided, The plurality of recurators comprises a first adjacent group in which the one-sided recurators of the plurality of recurators are adjacent to each other in the circumferential direction, and a second adjacent group in which the other-sided recurators of the plurality of recurators are adjacent to each other in the circumferential direction. The first adjacent group and the second adjacent group are arranged alternately in the circumferential direction. The rotor yoke according to feature 3.

5. The recurctor group comprises a central recurctor positioned in the center in the circumferential direction, one or more side recurctors positioned on one side of the central recurctor in the circumferential direction, and one or more other side recurctors positioned on the other side of the central recurctor in the circumferential direction. The recesses corresponding to the one-sided recurctor and the other-sided recurctor are formed asymmetrically with respect to a second radial line passing through the circumferential central position of each recess, when viewed from the axial direction of the yoke side wall. The recess corresponding to the central recurctor is formed symmetrically with respect to the second radial line when viewed from the axial direction. The rotor yoke according to feature 1.

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