Motor core

Abstract

To provide a motor core that can support a magnet within a slot with a simple configuration. [Solution] The motor core includes a motor core body including a plurality of slots arranged in an annular shape at predetermined intervals, a plurality of magnets inserted into the plurality of slots, a pressing body that supports the plurality of magnets inserted into the plurality of slots from at least one of the ends of the plurality of slots in the direction along the central axis of the motor core body, and retaining plates attached to both ends along the central axis of the motor core body. The pressing body is made up of a spring member that is annular or C-shaped in plan view, with valleys that are raised in the direction toward the motor core body and peaks that are raised in the direction toward the motor core body alternately provided along the circumference of a circle centered on the central axis of the motor core body, and when installed at least one of the ends in the direction along the central axis of the motor core body, at least one of the valleys abuts against each end of the plurality of magnets.

Description

Technical Field

[0001] The technology of the present disclosure relates to a motor core.

Background Art

[0002] Some rotating electrical machines have a motor core, for example, a rotor core with a permanent magnet attached thereto. As one method of attaching a permanent magnet to a motor core, a method is known in which a permanent magnet is inserted into a slot provided in the motor core and then a resin composition is filled around it and cured.

[0003] Patent Document 1 below describes a method of fixing a magnet by heating a resin tablet of a predetermined size in a pot to soften and melt it, and then filling and curing the resin composition in the slot of the rotor core.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the method of Patent Document 1 above, the magnet can be stably fixed in the slot. However, a dedicated manufacturing apparatus is required to perform a series of operations of softening and melting the resin and filling it into the slot. Therefore, there is a need for a motor core that can assemble the magnet into the slot more simply and stably than such a method.

[0006] An object of the present disclosure is to provide a motor core that can support a magnet in a slot with a simple configuration.

Means for Solving the Problems

[0007] To achieve the above objective, a motor core according to a first aspect of the present disclosure comprises a motor core body including a plurality of slots arranged in an annular shape at predetermined intervals, a plurality of magnets inserted into the plurality of slots, a pressing body that supports the plurality of magnets inserted into the plurality of slots from at least one of the ends of the plurality of slots in the direction along the central axis of the motor core body, and retaining plates attached to both ends of the motor core body along the central axis, wherein the pressing body is made of a spring member that is annular or C-shaped in plan view, with valleys that are raised in the direction toward the motor core body and peaks that are raised in the direction toward away from the motor core body alternately provided along the circumference of the motor core body centered on the central axis, and when installed at least one of the ends in the direction along the central axis of the motor core body, at least one of the valleys abuts against each end of the plurality of magnets.

[0008] In the motor core described above, using a pressing element makes it possible to assemble magnets into the slots with a simple configuration.

[0009] A motor core according to a second aspect of the present disclosure is a motor core according to the first aspect of the present disclosure, wherein a housing portion capable of housing the pressing body is formed on at least one of the surfaces of the retaining plate adjacent to the motor core body, or the surface of the motor core body to which the pressing body contacts.

[0010] In the motor core described above, the pressing element is not exposed to the outside, and the assembled state of the magnet is stable.

[0011] A motor core according to a third aspect of the present disclosure is a motor core according to the first or second aspect of the present disclosure, wherein the length of the plurality of magnets in the direction along the central axis when inserted into the plurality of slots is shorter than the length of the plurality of slots in the direction along the central axis.

[0012] In the motor core described above, the entire magnet fits within the slot, making the assembly of the motor core easier.

[0013] A motor core according to a fourth aspect of the present disclosure is a motor core according to any of the first to third aspects of the present disclosure, wherein the pressing body includes a plurality of spring members adjusted to different diameters.

[0014] In the motor core described above, by using multiple spring members, the magnets can be assembled stably regardless of the slot layout.

[0015] A motor core according to a fifth aspect of the present disclosure is a motor core according to any of the first to fourth aspects of the present disclosure, wherein at least one of the retaining plate and the motor core body includes a positioning portion for positioning the pressing body.

[0016] In the motor core described above, the position of the pressing element relative to the magnet becomes easier to adjust.

[0017] A motor core according to a sixth aspect of the present disclosure is a motor core according to any of the first to fifth aspects of the present disclosure, wherein all of the valleys are in contact with the plurality of magnets housed in the plurality of slots.

[0018] In the motor core described above, the magnet assembly is stable. [Effects of the Invention]

[0019] According to the motor core of this disclosure, a magnet can be supported in a slot with a simple configuration. [Brief explanation of the drawing]

[0020] [Figure 1] This is an exploded perspective view showing an example of a motor core according to one embodiment of the present disclosure. [Figure 2] This is a magnified view of one end of the motor core shown in Figure 1. [Figure 3] This is a cross-sectional view of the assembled motor core, cut along line AA shown in Figure 2. [Figure 4] It is an enlarged view of part B in FIG. 3. [Figure 5] It is a cross-sectional view corresponding to FIG. 3 of the motor core according to one modification example. [Figure 6] It is a cross-sectional view corresponding to FIG. 3 of the motor core according to another modification example. [Figure 7] It is a plan view of the motor core according to still another modification example with the retaining plate omitted.

Embodiments for Implementing the Invention

[0021] Hereinafter, each embodiment for implementing the present disclosure will be described with reference to the drawings. In the following, the scope necessary for the description for achieving the object of the present disclosure is schematically shown, and mainly the scope necessary for the description of the corresponding part of the present disclosure will be described, and the parts omitted from the description shall be based on known techniques. Also, the same or corresponding members in the drawings are given the same or similar reference numerals, and duplicate descriptions are omitted. Further, when a plurality of the same or corresponding members in the drawings are included, for the sake of easy viewing of the drawing, in some cases, only some of them are given reference numerals.

[0022] FIG. 1 is an exploded perspective view showing an example of a motor core according to an embodiment of the present disclosure. The motor core 1 according to this embodiment may be a component of a motor to which a magnet is attached, and for example, as shown in FIG. 1, it can be a rotor core that constitutes an inner rotor type motor.

[0023] The motor core 1 according to this embodiment includes at least a motor core body 10 including a plurality of slots 12 arranged annularly at a predetermined interval, a plurality of magnets 20 inserted into the plurality of slots 12, a pressing body 30 that supports the plurality of magnets 20 inserted into the plurality of slots 12, and retaining plates 40 attached to both ends along the central axis of the motor core body 10.

[0024] The motor core body 10 can be made of a substantially cylindrical magnetic material composed of multiple core pieces 15 (see Figure 3) made of relatively thin electromagnetic steel sheets, which are stacked together. The number of core pieces 15 that make up the motor core body 10 is not particularly limited, but can be, for example, 50 to 400 pieces. The thickness of the core pieces 15 may be, for example, 0.05 to 2.00 mm. Furthermore, the multiple core pieces 15 may be simply stacked together, crimped together by crimping parts (not shown) formed on each core piece 15, joined together by applying adhesive between the core pieces 15, or at least partially welded together.

[0025] Furthermore, the axial portion of the motor core body 10 may be provided with a through hole 11 into which a shaft (not shown) that constitutes the rotating axis when assembled as a motor is inserted. Inside this through hole 11, one or more (two in Figure 2) protrusions 11A may be provided to support the aforementioned shaft.

[0026] Furthermore, the motor core body 10 has multiple slots 12 (32 in Figure 1) arranged in a ring shape at predetermined intervals, extending along the central axis X of the motor core body 10 so as to surround the through-hole 11. These slots 12 can be shaped in such a way that a magnet 20 can be inserted, for example, they can be rectangular parallelepiped-shaped or arc-shaped through-holes in plan view that penetrate the motor core body 10 along the central axis X, but their specific shape and arrangement are not particularly limited. Similarly, the number of slots 12 can be arbitrarily changed, and may be more or less than the 32 shown in Figure 1.

[0027] In this embodiment, the slots 12 are characterized by being rectangular through-holes whose openings radiate radially from a central axis X, and whose circumferential spacing is set to be equal. In addition, the slots 12 in this embodiment include those with different longitudinal lengths of the aforementioned rectangular openings. The layout, including the extension direction and arrangement of each slot 12 in a plan view, is not limited to those described above and can be appropriately changed considering the direction and strength of the magnetic field generated around the magnet 20.

[0028] The magnet 20 can be made of a permanent magnet and is inserted into and supported inside the slot 12 of the motor core body 10. This magnet 20 can be made, for example, a rectangular parallelepiped or a block with a circular arc shape in plan view that is slightly smaller than the slot 12. Furthermore, it is not necessary for the magnet 20 to be magnetized or not at the time of insertion into the slot 12. In addition, the magnet 20 may be divided in a direction along the central axis X or in a direction perpendicular to the direction along the central axis X. Figure 1 shows the magnet 20 partially inserted into the slot 12.

[0029] The pressing body 30 is composed of a spring member that is annular or C-shaped in plan view, with valleys 31 that rise in the direction toward the motor core body 10 and peaks 32 that rise in the direction toward the motor core body 10 alternately arranged along a circumference centered on the central axis X. In this embodiment, the pressing body 30 is a substantially annular wave spring made of a strip-shaped metal plate, with the edges of the valleys 31 and peaks 32 formed to extend radially around the central axis X. The layout of the valleys 31 and peaks 32 of the pressing body 30 and the direction of extension of the edges are appropriately changed in accordance with the arrangement and extension direction of the slots 12 of the motor core body 10. Therefore, for example, the present disclosure may also include cases where the valleys 31 and peaks 32 are not formed radially around the central axis X.

[0030] Preferably, the valley portion 31 of the pressing body 30 described above has an arc-shaped curve when viewed from the side. When the valley portion 31 is curved in an arc shape, the contact point 50 can be substantially made into a surface contact when it comes into contact with the magnet 20. As a result, a support structure with high wear resistance can be obtained. Note that the shape of the valley portion 31 is not limited to the arc shape described above, and may be, for example, a bent shape when viewed from the side, or a shape having a flat surface extending along the end face 21 of the magnet 20.

[0031] Figure 2 is a magnified view of one end of the motor core shown in Figure 1. In Figure 2, the magnets 20 and pressing bodies 30 are assembled to the motor core body 10, starting from the disassembled state of each component as shown in Figure 1. The pressing bodies 30 are installed on at least one end of the motor core body 10 in the direction along the central axis X. In this embodiment, one pressing body 30 is installed at each end of the motor core body 10, as shown in Figure 1. The pressing bodies 30 installed at the ends of the motor core body 10 in the direction along the central axis X have their valleys 31 in contact with the end faces 21 of each of the multiple magnets 20, as shown in Figure 2. In this regard, the layout of the valleys 31 and the installation position of the pressing bodies 30 on the motor core body 10 are pre-adjusted. Details of the support structure of the magnets 20 by the pressing bodies 30 will be described later.

[0032] The retaining plates 40 are installed one at each end of the motor core body 10 in the direction along the central axis X, and fix the motor core body 10 and the pressing body 30. The retaining plates 40 can be made of a metal such as aluminum or steel, have substantially the same outer diameter as the motor core body 10, and have a communication hole 41 formed substantially in the center that communicates with the through hole 11 of the motor core body 10. The retaining plates 40 can be fixed to the motor core body 10 and the pressing body 30 by, for example, fixing their outer edge portion 44 to the motor core body 10 with adhesive or the like, or by fixing them to a shaft inserted into the through hole 11, but the specific fixing structure is not limited to these.

[0033] Furthermore, it is preferable that the surface of the retaining plate 40 adjacent to the motor core body 10 in this embodiment, in other words, the surface facing the end of the motor core body 10, be provided with a receiving recess 42 as an example of a receiving portion capable of accommodating the pressing body 30. In this embodiment, a retaining plate 40 with a receiving recess 42 is shown as an example, but instead of or in addition to the receiving recess 42, a receiving portion for accommodating at least a part of the pressing body 30 may be provided on the surface of the motor core body 10 that the pressing body 30 contacts. Also, if the pressing body 30 is disposed only on one end face of the motor core body 10, it is preferable to provide the above-mentioned receiving recess 42 on only one of the two retaining plates 40, and to make the surface of the other retaining plate 40 facing the motor core body 10 substantially flat so that one opening of the slot 12 can be closed.

[0034] Furthermore, it is preferable that at least one of the retaining plate 40 or the motor core body 10 is provided with a positioning section for positioning the pressing body 30. In this embodiment, as shown in Figure 1, one or more positioning grooves 43, as an example of a positioning section, are provided on the side wall surface of the receiving recess 42 (two in Figure 1). These positioning grooves 43 accommodate the positioning projections 33 provided on the outer circumference of the pressing body 30 when it is assembled. When the positioning projections 33 are accommodated in the positioning grooves 43, the pressing body 30 can be positioned relative to the retaining plate 40, particularly in the rotational direction about the central axis X. By providing the positioning grooves 43 described above, the positioning of the valley portion 31 and the magnet 20 becomes easier.

[0035] The configuration of the positioning section is not limited to those described above, and can be changed as appropriate as long as the positioning of the pressing body 30 is possible. The arrangement, shape, and number of these sections can also be adjusted as appropriate. Specifically, for example, the shape of the receiving recess formed in the pressing plate 40 can be made annular to match the shape of the pressing body 30, one or more positioning grooves can be formed on the inner and / or outer wall surfaces of the annular receiving recess, and positioning protrusions can be provided at corresponding positions on the inner and / or outer sides of the pressing body 30.

[0036] The motor core 1 according to this embodiment adopts the above-described configuration, particularly the configuration related to the pressing body 30, making it possible to support the magnet 20 within the slot 12 of the motor core body 10 without performing resin molding as exemplified in the prior art. The support structure will be described in more detail below.

[0037] Figure 3 is a cross-sectional view of the assembled motor core cut along line AA shown in Figure 2. When the motor core 1 is assembled, the pressing body 30 is housed in the housing recess 42 so as to be sandwiched between the motor core body 10 and the retaining plate 40, as shown in Figure 3. At this time, the arrangement and size of the valleys 31 formed on the pressing body 30 are adjusted in advance to match the arrangement of the slots 12, etc., and the position of the pressing body 30 relative to the motor core body 10 is adjusted by the positioning grooves 43 and positioning projections 33. Specifically, in this embodiment, the number of valleys 31 is the same as the number of slots 12, and the position of all valleys 31 is adjusted so that they contact one of the multiple magnets 20.

[0038] As a result of the adjustments described above, in the assembled motor core 1, as shown in Figure 3, the valleys 31 of the pressing body 30 contact the end faces 21 of the magnet 20 one by one in the direction along the central axis X. At this time, a portion of the valleys 31 of the pressing body 30 enters the inside of the slot 12. In addition, the peaks 32 formed between adjacent valleys 31 contact the bottom surface of the receiving recess 42 of the retaining plate 40. As a result, even when an external force is applied to the pressing body 30 during motor rotation, the valleys 31 do not separate from the end faces 21, and the magnet 20 can be stably supported.

[0039] Figure 4 is an enlarged view of section B in Figure 3. The valley portion 31 that contacts the end face 21 of the magnet 20 is curved in an arc shape, as shown in Figure 4. Furthermore, the end face 21 of the magnet 20 is substantially flat. Therefore, the contact point 50 between the end face 21 and the valley portion 31 becomes surface contact due to the slight deformation of the surface of the valley portion 31. By making the contact point 50 surface contact in this way, a relatively large contact area is secured, thereby reducing localized wear of the valley portion 31 or the magnet 20. In this embodiment, the case in which the end face 21 is substantially flat is illustrated, but the end face 21 may have irregularities formed on it.

[0040] Incidentally, if the length of the magnet 20 along its central axis X is the same as the length of the motor core body 10, or in other words, the length of the slot 12 along its central axis X, the magnet 20 will be less likely to move within the slot 12, which is preferable. However, due to factors such as slight variations in the thickness of the core piece 15, it can be difficult to make the two lengths mentioned above match. If, for example, the length of the magnet 20 along its central axis X becomes longer than the length of the motor core body 10 along its central axis X due to the aforementioned variations, the magnet 20 will protrude from the opening of the slot 12, and in some cases, it may become difficult to fix it with the retaining plate 40.

[0041] Therefore, in this embodiment, the length of the magnet 20 in the direction along the central axis X is set to be shorter than the length of the motor core body 10 in the direction along the central axis X. With this setting, when the magnet 20 is housed in the slot 12, the position of the end face 21 of the magnet 20 is located inside the slot 12 by a length G (for example, a length less than or equal to the thickness of one core piece 15) than the position of the end face of the motor core body 10. However, as described above, in this embodiment, the pressing body 30 contacts the end face 21 of the magnet 20 by having a part of the valley portion 31 enter into the slot 12. Therefore, even if the length of the magnet 20 in the direction along the central axis X is shorter than the length of the motor core body 10 in the direction along the central axis X, the contact point 50 can be stably formed. Furthermore, by configuring the pressing body 30 as an annular or C-shaped spring member, multiple magnets 20 can be supported by a single spring member, and the number of parts can be reduced compared to when each magnet 20 is pressed and supported by a pressing member, making the assembly of the motor core 1 easier.

[0042] As described above, according to the motor core 1 of this embodiment, the magnet 20 can be assembled to the motor core body 10 with a simple configuration by using the pressing body 30.

[0043] Below, we will describe some modified versions of the motor core 1 according to the above-described embodiment.

[0044] In the embodiment described above, in relation to the fact that the slots 12 are formed at equal intervals in the circumferential direction, an example was given in which the spacing D between adjacent valleys 31 of the pressing body 30 is the same. However, the spacing D may be different for each of them. Below, an example of a modified example in which the spacing between valleys 31 is not constant will be described with reference to Figure 5. In the motor core 1A of the modified example shown in Figure 5, the same reference numerals are used for components that are the same as those of the motor core 1 according to the embodiment described above, and their descriptions will be omitted. Only the differences from the motor core 1 according to the embodiment will be described.

[0045] Figure 5 is a cross-sectional view of a motor core according to one modified example, corresponding to Figure 3. In this modified example, as shown in Figure 5, the motor core body 10A, which is composed of multiple core pieces 15A, has multiple slots 12A that are not spaced equally in the radial direction. Therefore, in the pressing body 30A of the motor core 1A of this modified example, the spacing between the valleys 31A is also adjusted to match the position of the slots 12. Specifically, the gap D1 between the valleys 31A corresponding to the location where the distance between slots 12A is relatively short is adjusted to be shorter than the gap D2 between the valleys 31A corresponding to the location where the distance between slots 12A is relatively long. By adjusting the arrangement of the valleys 31A of the pressing body 30 in this way, the magnet 20 can be assembled reliably.

[0046] Furthermore, in the embodiment described above, an example was shown in which all of the valleys 31 abut against one of the end faces 21 of the multiple magnets 20. However, it is not necessarily required that all of the valleys 31 abut against the end faces 21 of the multiple magnets 20. Below, another modification of one embodiment in which a part of the valleys does not abut against the multiple magnets 20 will be described with reference to Figure 6. In the motor core 1B of the other modification shown in Figure 6, the same reference numerals are used for components that are the same as those of the motor core 1 according to the embodiment described above, and their descriptions will be omitted. Only the differences from the motor core 1 according to the embodiment will be described.

[0047] Figure 6 is a cross-sectional view of a motor core relating to another modification, corresponding to Figure 3. In this modification, as shown in Figure 6, the motor core 1B, which is composed of a motor core body 10B made up of a plurality of core pieces 15B, has a larger radial spacing between the plurality of slots 12B than that of the embodiment described above. The pressing body 30B of the motor core 1B of this modification includes a valley portion 31B that contacts the end face 21 of the magnet 20 and a valley portion 31C that does not contact the end face 21 of the magnet 20. Of these, the valley portion 31C that does not contact the end face 21 of the magnet 20 contacts the end face of the motor core body 10A. This contact pushes the valley portion 31C in the direction of the peak portion 32, thereby pressing the valley portion 31B that contacts the end face 21 of the magnet 20 against the end face 21 of the magnet 20. This makes it possible to more reliably bring the end face 21 of the magnet 20 and the valley portion 31B into contact.

[0048] Furthermore, in the above-described embodiment, the pressing body 30 was exemplified as including one spring member, but it may include two or more spring members. Hereinafter, another modification of the embodiment, in which the pressing body is composed of two spring members, will be described with reference to Figure 7. In the motor core 1C of the other modification shown in Figure 7, components similar to those of the motor core 1 in the above-described embodiment will be denoted by the same reference numerals and their descriptions will be omitted, and only the differences from the motor core 1 in the embodiment will be described.

[0049] Figure 7 is a plan view of a motor core with the retaining plate omitted, relating to yet another modified example. In this modified example, as shown in Figure 7, the motor core 1C has a slot 12C formed in the motor core body 10C, which is inclined at a predetermined angle with respect to the radial direction with respect to the central axis X of the motor core body 10. In this modified example, as shown in Figure 7, the pressing body consists of a first pressing body 30C arranged to cross the outer portion of the aforementioned slot 12C, and a second pressing body 30C arranged to cross the inner portion of the slot 12C, both arranged coaxially. The first pressing body 30C and the second pressing body 30D have different diameters, with the first pressing body 30C having a larger diameter than the second pressing body 30D. The first and second pressing bodies 30C and 30D can be made of the same spring members as the pressing body 30 described in one embodiment, and the arrangement of their valleys and peaks and the direction of extension of their ridges can be adjusted in accordance with the arrangement of the magnets 20, etc., in the same way as the pressing body 30 of one embodiment. With the motor core 1C of this modified example, the magnets 20 can be pressed and supported at multiple locations using a plurality of pressing bodies 30C and 30D, so the assembled state of the magnets 20 can be made more stable.

[0050] This disclosure is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit of this disclosure. All such modifications are included in the technical concept of this disclosure. Furthermore, in this disclosure, each component may exist only once or in multiples, as long as it does not create a contradiction. [Explanation of Symbols]

[0051] 1, 1A, 1B, 1C Motor Cores 10, 10A, 10B, 10C Motor Core Body 12, 12A, 12B, 12C slots 15, 15A, 15B core pieces 20 magnets 21 End face 30, 30A, 30B Pressing body 30C First pressing body 30D Second pressing body 31, 31A, 31B, 31C Tanibe 32 Yamabe 40 Pressing plate 42 Recessed compartment (an example of a compartment) 43 Positioning groove (an example of a positioning section) 50 contacts

Claims

1. A motor core body including multiple slots arranged in a ring shape at predetermined intervals, Multiple magnets inserted into the aforementioned multiple slots, A pressing body that supports the plurality of magnets inserted into the plurality of slots from at least one of the ends of the plurality of slots in a direction along the central axis of the motor core body, The motor core body comprises retaining plates attached to both ends along the central axis, The pressing body is composed of a spring member that is annular or C-shaped in plan view, with valleys that rise in the direction toward the motor core body and peaks that rise in the direction toward away from the motor core body alternately arranged along the circumference of the motor core body with respect to the central axis, and when installed at least one of the ends in the direction toward the central axis of the motor core body, at least one of the valleys abuts against each end of the plurality of magnets. Motor core.

2. A housing portion capable of accommodating the pressing body is formed on at least one of the surfaces of the pressing plate adjacent to the motor core body, or on the surface of the motor core body to which the pressing body makes contact. The motor core according to claim 1.

3. The length of the plurality of magnets in the direction along the central axis when inserted into the plurality of slots is shorter than the length of the plurality of slots in the direction along the central axis. The motor core according to claim 1.

4. The pressing body includes a plurality of spring members adjusted to different diameters. The motor core according to claim 1.

5. At least one of the pressing plate and the motor core body is provided with a positioning part for positioning the pressing body. The motor core according to claim 1.

6. All of the valleys are in contact with the plurality of magnets housed in the plurality of slots. The motor core according to claim 1.

Images