STATOR CORE FOR ROTATING ELECTRICAL MACHINE, ROTATING ELECTRICAL MACHINE, AND METHOD OF MANUFACTURING ROTATING ELECTRICAL MACHINE
20170331336 · 2017-11-16
Assignee
Inventors
Cpc classification
H02K1/18
ELECTRICITY
International classification
Abstract
A stator core for a rotating electrical machine includes core segments each including a stack of at least one first core member and at least one second core member. The first core member has an arc-shaped first yoke, a first tooth protruding from an inner peripheral side of an arc of the first yoke, a recessed portion provided at a first end of the first yoke, and a protruding portion provided at a second end of the first yoke. The second core member has an arc-shaped second yoke having both linear-shaped ends, and a second tooth protruding from an inner peripheral side of an arc of the second yoke. The recessed portions and the protruding portions of the core segments are combined to form an annular structure, and a dimension of the recessed portion in a radial direction of the annular structure is larger than a dimension of the protruding portion in the radial direction of the annular structure.
Claims
1. A stator core for a rotating electrical machine, the stator core comprising: a plurality of core segments each comprising a stack of at least one first core member and at least one second core member, the at least one first core member having a first yoke of a shape including an arc, a first tooth protruding from an inner peripheral side of the first yoke, a recessed portion provided at a first end of the first yoke, and a protruding portion provided at a second end of the first yoke, and the at least one second core member having a second yoke of a shape including an arc and having both linear-shaped ends, and a second tooth protruding from an inner peripheral side of the second yoke, wherein the recessed portions and the protruding portions of the plurality of core segments are combined to form an annular structure, and a dimension of the recessed portion in a radial direction of the annular structure is larger than a dimension of the protruding portion in the radial direction of the annular structure, and the protruding portion and the recessed portion contact each other in a circumferential direction of the annular structure.
2. The stator core for the rotating electrical machine according to claim 1, wherein, in each of the core segments, the at least one first core member is sandwiched between at least two of the second core members.
3. The stator core for the rotating electrical machine according to claim 1, wherein a following formula holds: a−b>M−N where M is a maximum value of an inner diameter of the annular structure, N is a minimum value of the inner diameter, a is the dimension of the recessed portion in the radial direction of the annular structure, and b is the dimension of the protruding portion in the radial direction of the annular structure.
4. A rotating electrical machine comprising: the stator core for the rotating electrical machine according to claim 1; windings placed around the stack of the first and second teeth; a housing holding the stator core for the rotating electrical machine; and a rotor disposed radially inwardly of the stator core for the rotating electrical machine.
5. A method of manufacturing a rotating electrical machine, the method comprising: manufacturing the stator core for the rotating electrical machine according to claim 1, wherein manufacturing the stator core comprises: stacking at least one first core member and at least one second core member to form a core segment, the at least one first core member having a first yoke of a shape including an arc, a first tooth protruding from an inner peripheral side of the first yoke, a recessed portion provided at a first end of the first yoke, and a protruding portion provided at a second end of the first yoke, and the at least one second core member having a second yoke of a shape including an arc and having both linear-shaped ends, and a second tooth protruding from an inner peripheral side of the second yoke; forming an annular stator core for the rotating electrical machine by disposing, on an outer side of a cylindrical jig, a plurality of the core segments with the recessed portions and the protruding portions being combined together; and mounting, in a housing, the stator core for the rotating electrical machine mounted on the jig.
6. The method of manufacturing the rotating electrical machine according to claim 5, wherein the stator core for the rotating electrical machine is mounted in the housing by shrink fitting.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENT
[0029] Hereinafter, a laser machining device according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiment described below is not intended to limit the present invention.
Embodiment
[0030] In the embodiment, a rotating electrical machine is exemplified by a permanent magnet motor. In the embodiment, the rotating electrical machine only needs to have a segmented stator, and may be a switched reluctance motor (SRM), not limited to a permanent magnet motor. The rotating electrical machine is not limited to a motor, that is, an apparatus for generating motive power, and may be a generator for generating electric power.
[0031]
[0032] The housing 2 has a tubular side portion 2S, a first flange 2T mounted to one end of the side portion 2S, and a second flange 2B mounted to an opposite end of the side portion 2S. As illustrated in
[0033] The stator 6 is mounted on an inner surface 2SI of the side portion 2S. The inner surface 2SI of the side portion 2S has a circular cross section when cut along a plane orthogonal to the rotation center axis Zr. The stator 6 is disposed in the through hole 2SH of the side portion 2S. The rotor 10 is disposed inside the stator 6. The through hole 2SH of the side portion 2S is closed by the first flange 2T mounted to the one end of the side portion 2S and the second flange 2B mounted to the opposite end. The stator 6 and the rotor 10 are housed in a space surrounded by the side portion 2S, the first flange 2T, and the second flange 2B. That is, the stator 6 and the rotor 10 are housed in the through hole 2SH.
[0034] The first flange 2T has a hole 2TH. The shaft 3 on which the rotor core 5 is mounted extends through the hole 2TH. The bearing 4T is mounted in the hole 2TH of the first flange 2T. The bearing 4B is mounted in the second flange 2B. Since the shaft 3 has one end portion and an opposite end portion that are supported by the pair of bearings 4T and 4B as described above, the shaft 3 and the rotor 10 are supported by the first flange 2T and the second flange 2B via the pair of bearings 4T and 4B. The pair of bearings 4T and 4B are exemplified by ball bearings, but are not limited to them.
[0035]
[0036] The rotor 10 is disposed radially inwardly of the stator core 8 that is the annular structure. The radial direction shown by arrows RD in
[0037] The permanent magnets 7 are mounted on the rotor core 5 by bonding. The way of mounting the permanent magnets 7 on the rotor core 5 is not limited to this. In the embodiment, the permanent magnets 7 are mounted on the outer peripheral surface 5P of the rotor core 5. Alternatively, holes extending through the rotor core 5 in the direction of the rotation center axis Zr may be provided, such that the permanent magnets 7 can be mounted in the holes.
[0038] A gap SA is provided between the rotor core 5 and an inner peripheral portion 81 of the stator core 8. Magnetic flux of the permanent magnets 7 is produced in the gap SA. The rotor 10 is rotated by torque produced due to the interaction between magnetic flux produced by the permanent magnets 7 and magnetic flux produced by the windings 9. Next, the stator core 8 will be described in more detail.
[0039]
[0040] As illustrated in
[0041] The outer peripheral portion 8SYE of the arc of the yoke 8SY has an arc shape. The radius of curvature of the outer peripheral portion 8SYE is slightly larger than the radius of the inner surface 2SI of the side portion 2S illustrated in
[0042] An inner diameter Di of the stator core 8 is the length of a line segment passing through the rotation center axis Zr having both end points located on the surfaces of the inner peripheral portions 81 of the stator core 8. Depending on the assembly accuracy of the core segments 8S, the stator core 8S can have different inner diameters Di for different portions thereof in a direction C along the circumference of the stator core 8. The smaller the variations in the inner diameter Di of the stator core 8 among the portions of the stator core 8 in the direction C along the circumference of the stator core 8, the higher the roundness of the inner diameter Di.
[0043] When the stator core 8 is mounted in the side portion 2S of the housing 2, the notches 8SS engage protruding portions provided on the inner surface 2SI of the side portion 2S illustrated in
[0044] Since the teeth 8ST protrude from the side of the inner peripheral portions 8SYI of the arcs of the yokes 8SY toward the rotation center axis Zr, the shape of the core segments 8S as viewed from the direction of the rotation center axis Zr is a T-shape. The core segments 8S form the stator core 8 of the annular structure with the arc-shaped yokes 8SY combined at their ends. When the plural core segments 8S are combined, the recessed portion 8U provided at the one end of the yoke 8SY is combined with the protruding portion 8T provided at the opposite end of the adjacent yoke 8SY. Combining the recessed portion 8U of the core segment 8S and the protruding portion 8T of the adjacent core segment 8S suppresses the displacement of the core segments 8S of the stator core 8 in the direction of the rotation center axis Zr and the radial direction that is the direction orthogonal to the rotation center axis Zr.
[0045] In the embodiment, the stator core 8 has the twelve teeth 8ST. A space between the adjacent teeth 8ST and 8ST is a slot 8SL. In the embodiment, thus, the stator core 8 has twelve slots 8SL. The stator core 8 has the windings 9 illustrated in
[0046] The core segment 8S of the stator core 8 is a stack of at least one first core member 20 illustrated in
[0047] The first core member 20 and the second core member 30 are both plate-shaped members made of an electromagnetic steel sheets of a magnetic substance. Surfaces orthogonal to thickness directions of the first core member 20 and the second core member 30 that are the plate-shaped members are defined as a surface 20P and a surface 30P. Since the first tooth 22 of the first core member 20 protrudes from the side of the inner peripheral portion 21I of the arc of the first yoke 21 toward the rotation center axis Zr, the shape of the first core member 20 as viewed from the direction orthogonal to the surface 20P is a T-shape. Likewise, since the second tooth 32 of the second core member 30 protrudes from the side of the inner peripheral portion 311 of the arc of the second yoke 31 toward the rotation center axis Zr, the shape of the second core member 30 as viewed from the direction orthogonal to the surface 30P is a T-shape.
[0048] The first core member 20 has the recessed portion 23 provided at the first end 21Ta of the first yoke 21, and the protruding portion 24 provided at the second end 21Tb of the first yoke 21. The recessed portion 23 and the protruding portion 24 are not provided at the first end 31Ta and the second end 31Tb of the second yoke 31 of the second core member 30. Thus, the first end 31Ta and the second end 31Tb of the second yoke 31 are both linear-shaped when the second core member 30 is viewed from the direction orthogonal to the surface 30P.
[0049] When first core members 20 and second core members 30 are stacked, the surfaces 20P contact one another or the surface 20P and the surface 30P contact one another. Stacking the first core members 20 and second core members 30 forms the core segment 8S illustrated in
[0050] The core segment 8S is manufactured by stacking at least one first core member 20 and at least one second core member 30, and tightening the stacked first and second core members 20, 30 together. Alternatively, the core segment 8S may be manufactured by riveting, screwing, welding or bonding the stacked first and second core members 20, 30. The rotor core 5 is manufactured in the same manner as the core segments 8S.
[0051] In the embodiment, as illustrated in
[0052] The core segment 8S has a structure in which at least one first core member 20 is sandwiched between at least two second core members 30. Therefore, the recessed portion 23 and the protruding portion 24 of the core segment 8S are formed between the second core members 30 and 30 located at both ends of the core segment 8S in the direction of the stacking of the first core member 20 and the second core members 30. When the plural core segments 8S are combined together such that the protruding portions 24 fit in the recessed portions 23, thus, the second core members 30, which are located at the both ends of the core segment 8S in the stacking direction, prevent the core segments 8S from moving in the stacking direction.
[0053] The recessed portions 8U and the protruding portions 8T of the core segments 8S are preferably provided in the same level in the stacking direction. This can prevent displacement of both ends of the stator core 8 in the direction parallel to the rotation center axis Zr. Although the recessed portions 8U and the protruding portions 8T are provided in the central portion of the core segment in the stacking direction in the embodiment, they need do not have to be provided in the central portion in the stacking direction as long as they are in the same level in the stacking direction. For example, the recessed portion 8U and the protruding portion 8T may be provided at one end of the core segment 8S in the stacking direction.
[0054] The stator core 8 is the annular structure formed by combining the recessed portions 8U and the protruding portions 8T of the plural core segments 8S. As illustrated in
[0055] It is preferable that the following formula holds: a−b>M−N where M is the maximum value of the inner diameter Di of the stator core 8, and N is the minimum value of the inner diameter Di. This ensures that variation in the inner diameter Di of the stator core 8 is accommodated by the recessed portions 23 and the protruding portions 24 of the core segments 8S.
[0056] A dimension Tu of the recessed portion 23 of the first core member 20 in the direction C along the circumference of the stator core 8 is larger than a dimension Tt of the protruding portion 24 in the direction C along the circumference of the stator core 8. This structure enables the protruding portion 24 of the core segment 8S to avoid contacting the bottom 23B of the recessed portion 23 of the adjacent core segment 8S when the plural core segments 8S are combined together. As a result, the first ends 21Ta and 31Ta and the second ends 21Tb and 31Tb of the core segments 8S and 8S adjacent to each other when the plural core segments 8S are combined together contact to reduce the magnetic reluctance, thus improving the magnetic properties of the stator core 8.
[0057]
[0058] When the recessed portions 23 and the protruding portions 24 of the core segments 8S formed by stacking the first core members 20 and the second core members 30 are combined together, gaps SR are formed in the radial direction RD in the cross sections of the core segments 8S, as illustrated in
[0059] As illustrated in
[0060] In the stator core 8, the flow of magnetic flux in the rotation center axis Zr direction and the radial direction RD of magnetic flux occurs only between the recessed portions 23 and the protruding portions 24. The recessed portions 23 and the protruding portions 24 of the first core members 20, or the recessed portions 8U and the protruding portions 8T of the core segments 8S are part of the connections between the adjacent core segments 8S. Therefore, the stator core 8 can suppress the flow of magnetic flux in the rotation center axis Zr direction and the radial direction RD of magnetic flux, and thus suppress the occurrence of iron loss. This enables the motor 1 including the stator core 8 to reduce the energy consumption. Next, a method of manufacturing a rotating electrical machine including a method of manufacturing a stator core will be described.
[0061]
[0062] Next, the process proceeds to step S102, in which, as illustrated in
[0063] The stator core 8, which is formed by combining the plural core segments 8S without requiring screwing or riveting, is easy to disassemble. The easy disassembly facilitates collection of the stator core 8 when the motor 1 is discarded. Further, the stator core 8 is disassembled into the plural core segments 8S that are easy to collect and transport after the disassembly of the stator core 8.
[0064] In the embodiment, after the windings 9 illustrated in
[0065] In step S104, as illustrated in
[0066] In step S104, the side portion 2S is heated until the inner diameter of the through hole 2SH of the side portion 2S becomes larger than the outside diameter of the stator core 8 mounted on the jig 40. Next, the stator core 8 mounted on the jig 40 is disposed in the through hole 2SH of the side portion 2S. Thereafter, the inner diameter of the through hole 2SH becomes small due to the contraction of the side portion 2S as the temperature of the side portion 2S decreases, so that the stator core 8 is secured to the side portion 2S.
[0067] When the stator core 8 is secured to the side portion 2S, the jig 40 is removed from the stator core 8. The stator core 8, which is secured to the side portion 2S, provides the roundness of the inner diameter Di of the stator core 8. Since the jig 40 is removed from the stator core 8 after the stator core 8 is secured to the side portion 2S in the embodiment, the roundness of the inside diameter Di of the stator core 8 secured to the side portion 2S is provided.
[0068] After the stator core 8 is secured to the side portion 2S, the plurality of windings 9 is connected. Next, in step 5105, the rotor 10 illustrated in
[0069] In the embodiment, the number of the first core members 20 is preferably set to a minimum necessary for positioning the core segment 8S and suppressing the displacement of the core segment 8S, and may be one. This can minimize the gaps SR illustrated in
[0070] One first core member 20 and one second core member 30 have one first tooth 22 and one second tooth 32, respectively, in the embodiment, but are not limited to this. One first core member 20 and one second core member 30 may have two or more first teeth 22 and two or more second teeth 32, respectively, as long as the condition that the plural core segments 8S form the stator core 8 is satisfied. This can reduce the number of core segments 8S, thus facilitating the manufacturing of the stator core 8.
[0071] The configuration described in the above embodiment shows an example of the subject matter of the present invention, and can be combined with another known art, and can be partly omitted or changed without departing from the scope of the present invention.
REFERENCE SIGNS LIST
[0072] 1 rotating electrical machine, 2 housing, 2S side portion, 2SI inner surface, 2TH hole, 3 shaft, 5 rotor core, 6 stator, 7 permanent magnet, 8 stator core, inner peripheral portion, 8S core segment, 8SL slot, 8ST tooth, 8SY yoke, 8SYE outer peripheral portion, 8SYI inner peripheral portion, 8T, 24 protruding portion, 8U, recessed portion, 9 winding, 10 rotor, 20 first core member, 21 first yoke, 21Ta, 31Ta first end, 21Tb, 31Tb second end, 22 first tooth, 30 second core member, 31 second yoke, 32 second tooth, 40 jig, 41 outer peripheral portion, SR gap, Zr rotation center axis.