Magnetic modulation body, magnetic modulation gear, and method for manufacturing magnetic modulation body

Abstract

The invention relates to a magnetic modulation body capable of easily managing the axial position of a magnetic pole piece. A magnetic modulation body (50) is provided with: a magnetic pole piece (54a); an output shaft part (51) and a bearing support ring (55) which are arranged along the axial direction of the magnetic pole pieces (54a) and are used for rotatably supporting the magnetic pole pieces (54a); and a resin part (56) which integrates the magnetic pole piece (54a) with the output shaft part (51) and the bearing support ring (55). At least one of the two axial end surfaces of the pole piece (54a) is exposed. As a result, the axial position of the end surface (54c) of the exposed pole piece (54a) can be directly measured.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-174936 filed on October 04, 2024. The entire contents of the Japanese application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to a magnetic modulation body, a magnetic modulation gear, and a manufacturing method of a magnetic modulation body. BACKGROUND

[0003] Conventionally, a magnetic modulation gear is known, in which a magnetic modulation body having a plurality of magnetic pole pieces is arranged between two magnet rotors arranged in the inner and outer periphery, to modulate the magnetic flux distribution between the two magnet rotors (for example, refer to Patent Literature 1).

[0004] In the magnetic modulation body, the magnetic pole piece and a support portion for rotationally supporting the magnetic pole piece are integrated by resin. The support portion is arranged in the axial direction of the magnetic pole piece, and the end surface in the axial direction of the magnetic pole piece is joined to the support portion via the resin.

[0005] Patent Literature 1: Japanese Patent No. 5350438

[0006] However, in the magnetic modulation body, since the end surface in the axial direction of the magnetic pole piece is covered with resin, it is difficult to manage the relative axial position between the magnetic pole piece and the magnet arranged in the inner and outer periphery thereof. If the axial position of the magnetic pole piece and the magnet is shifted, torque reduction due to leakage magnetic flux or thrust toward the magnetic stable position occurs, resulting in performance deterioration. SUMMARY

[0007] The present application was completed in view of the above circumstances, and aims to easily manage the axial position of the magnetic pole piece.

[0008] The present application relates to a magnetic modulation body, comprising:

[0009] a magnetic pole piece;

[0010] a support portion arranged in the axial direction of the magnetic pole piece and for rotationally supporting the magnetic pole piece; and

[0011] a resin portion integrating the magnetic pole piece and the support portion,

[0012] at least one of the two end surfaces in the axial direction of the magnetic pole piece is exposed.

[0013] EFFECT OF THE INVENTION

[0014] According to the present application, the axial position of the magnetic pole piece can be easily managed. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1is a cross-sectional view of a magnetic modulation gear according to an embodiment.

[0016] Figure 2 is a cross-sectional view taken along the III-III line of Figure 1 is a cross-sectional view taken along the III-III line of

[0017] Figure 3 is a cross-sectional view of a magnetic modulation body according to an embodiment.

[0018] Figure 4 is a cross-sectional view of a modification of the magnetic modulation body according to an embodiment.

[0019] Figure 5 is a view of the modification of the magnetic modulation body according to an embodiment, as viewed from the output side.

[0020] Figure 6 is a flowchart showing the general manufacturing procedure of the magnetic modulation body according to an embodiment.

[0021] Figure 7 is a cross-sectional view showing the state in which the magnetic pole piece and the like are arranged in the molding die at the time of molding of the resin portion.

[0022] In the drawing: 1 - magnetic modulation gear, 12 - outer magnetic pole body, 12a - outer magnet, 41a - inner magnetic pole body, 41b - inner magnet, 50 - magnetic modulation body, 51 - output shaft portion (support portion), 54 - intermediate magnetic pole body, 54a - magnetic pole piece, 54b - connecting portion, 55 - bearing support ring (support portion), 56 - resin portion, 56a - hole portion, 71 - first molding die, 72 - second molding die, Ax - center axis, S - filling space. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present application will be described in detail with reference to the drawings.

[0024] [Overall structure of magnetic modulation gear]

[0025] Figure 1 is a cross-sectional view of a magnetic modulation gear 1 according to the present embodiment, Figure 2 is a cross-sectional view taken along the III-III line of Figure 1 is a cross-sectional view taken along the III-III line of

[0026] In the following description, the direction along the center axis Ax of the magnetic modulation gear 1 will be referred to as the "axial direction", the direction perpendicular to the center axis Ax will be referred to as the "radial direction", and the direction of rotation about the center axis Ax will be referred to as the "circumferential direction". Also, in the axial direction, the side (left side of Figure 1 ) coupled to the driven member outside will be referred to as the "output side", and the side (right side of Figure 1 ) opposite thereto will be referred to as the "input side".

[0027] As shown in Figure 1 and Figure 2 shown, the magnetic modulation gear 1 according to the present embodiment includes a housing (frame) 10, an input side cover 20 and an output side cover 30 that cover both sides in the axial direction of the housing 10, and an input shaft 40 and a magnetic modulation body 50 that are housed inside them.

[0028] The housing 10 is formed in a substantially cylindrical shape with the center axis Ax as the center, and has a stator yoke 11 and an outer pole body 12 in the inner peripheral portion.

[0029] The stator yoke 11 is formed in a cylindrical shape and is embedded in the housing 10.

[0030] The outer pole body 12 is composed of a plurality of outer magnets 12a. The plurality of outer magnets 12a are, for example, permanent magnets such as neodymium magnets, have a larger number of pole pairs than the inner magnets 41b of the input shaft 40 described later, and are attached to the inner peripheral surface of the stator yoke 11 in a manner in which magnets having different polarities are alternately arranged in the circumferential direction. However, the outer pole body 12 can also be a one-piece ring-shaped body, or can be a structure in which divided outer magnets 12a are arranged in the circumferential direction, and the like.

[0031] Further, in the inner peripheral portion of the housing 10, a bearing 61 (for example, a ball bearing) that supports the magnetic modulation body 50 so as to be rotatable is arranged further on the input side than the stator yoke 11.

[0032] The input side cover 20 is arranged on the input side of the housing 10 and covers the inner opening of the housing 10 from the input side. The outer peripheral portion of the input side cover 20 is fitted with the housing 10 by a lock catch. Further, in the inner peripheral portion of the input side cover 20, a bearing 62 (for example, a ball bearing) that supports the input shaft 40 so as to be rotatable is arranged.

[0033] The output side cover 30 is arranged on the output side of the housing 10 and covers the inner opening of the housing 10 from the output side. The outer peripheral portion of the output side cover 30 is fitted with the housing 10 by a lock catch. Further, in the inner peripheral portion of the output side cover 30, a bearing 63 (for example, a ball bearing) that supports the magnetic modulation body 50 so as to be rotatable is arranged.

[0034] The input shaft 40 is a shaft that rotates with the center axis Ax as the center and has a circular plate portion 41 and a motor connecting portion 42. This input shaft 40 is supported so as to be rotatable by the bearing 62 arranged between the input side cover 20 and the bearing 64 arranged between the magnetic modulation body 50.

[0035] The motor connecting portion 42 extends from the circular plate portion 41 toward the input side in the axial direction. The front end side of the motor connecting portion 42 protrudes to the outside from the input side cover 20, and this protruding portion is connected to a motor (omitted from the drawing).

[0036] The circular plate portion 41 has an inner magnetic pole body 41a disposed on the inner diameter side of the outer magnetic pole body 12 on its outer periphery. The inner magnetic pole body 41a is composed of a plurality of inner magnets 41b. The plurality of inner magnets 41b are permanent magnets such as neodymium magnets, and are attached to the outer peripheral surface of the circular plate portion 41 in a manner in which magnets of different polarities are alternately arranged in the circumferential direction. However, the inner magnetic pole body 41a may be a single ring-shaped body, or it may be a structure in which the divided inner magnets 41b are arranged in the circumferential direction, etc.

[0037] [Structure of the magnetic modulator]

[0038] like Figure 1 and Figure 2 As shown, the magnetic modulator 50 has an output shaft portion 51, a cylindrical portion 52, and a bearing support ring 55. The output shaft portion 51 and the bearing support ring 55 are examples of the support portions involved in the present invention, and are portions used for rotatably supporting the intermediate magnetic pole body 54 (magnetic pole piece 54a) described later.

[0039] The output shaft 51 is a metal shaft that rotates around the central axis Ax and is located on the output side of the intermediate magnetic pole 54, which will be described later. Approximately half of the output side of the output shaft 51 protrudes outward from the output side cover 30, and this protrusion is connected to the driven component (not shown).

[0040] The axially approximately central portion of the output shaft portion 51 is rotatably supported by a bearing 63 disposed between it and the output side cover 30. Furthermore, a bearing 64 (e.g., a ball bearing) is disposed at the input side end of the output shaft portion 51 to support the input shaft 40 for rotational movement. In the output shaft portion 51, the output side end of the cylindrical portion 52 is connected to the outer periphery at an axial position between the bearing 63 and the bearing 64.

[0041] The bearing support ring 55 is made of metal (e.g., stainless steel) and is disposed on the input side of the intermediate magnetic pole 54, which will be described later. The bearing support ring 55 is fixed to the outer peripheral side of the input side end of the cylindrical portion 52 and is fitted into the outer peripheral surface of the inner ring of the bearing 61 disposed between the bearing and the housing 10.

[0042] The cylindrical portion 52 is formed into a generally cylindrical shape centered on the central axis Ax, and has an intermediate magnetic pole 54 disposed at an axial position corresponding to the outer magnetic pole 12 and the inner magnetic pole 41a. The intermediate magnetic pole 54 has a plurality of magnetic pole pieces 54a.

[0043] Multiple magnetic pole pieces 54a are arranged at predetermined intervals in the circumferential direction, forming a ring. The multiple magnetic pole pieces 54a (the middle magnetic pole 54) are concentrically arranged with predetermined gaps between them and the inner diameter side of the outer magnetic pole 12 and the outer diameter side of the inner magnetic pole 41a. Each magnetic pole piece 54a is constructed by stacking thin electromagnetic steel plates (laminated steel plates) axially.

[0044] The magnetic pole pieces 54a adjacent to each other in the circumferential direction are connected by connecting portions 54b therebetween.

[0045] The connecting portions 54b are made of resin and constitute a part of a resin portion 56 described later.

[0046] The outer peripheral surface of the connecting portion 54b is more recessed toward the inner diameter side than the outer peripheral surface of the magnetic pole piece 54a.

[0047] However, the inner peripheral surface and the outer peripheral surface of the connecting portion 54b can be parallel to the corresponding surfaces of the magnetic pole piece 54a, or the inner peripheral surface can be recessed toward the outer diameter side.

[0048] Also, the connecting portion 54b can be integrally made of an electromagnetic steel sheet with the magnetic pole piece 54a. At this time, the radial position and the width of the connecting portion 54b are not particularly limited, but for example, it can be configured as described in International Publication No. 2023 / 026804 to obtain appropriate torque performance.

[0049] In the cylindrical portion 52, the portion other than the magnetic pole pieces 54a becomes a resin portion 56 made of resin (for example, super engineering plastic). That is, the portion other than the output shaft portion 51 and the bearing support ring 55 and the intermediate magnetic pole body 54 (the plurality of magnetic pole pieces 54a) in the magnetic modulation body 50 is the resin portion 56. Resin is also filled between the plurality of magnetic pole pieces 54a, and this portion constitutes the connecting portion 54b described above.

[0050] The end portion of the output side of the resin portion 56 protrudes toward the inner diameter side and is connected to the output shaft portion 51. In the inner peripheral portion of this end portion, a plurality of protrusions 57 protruding toward the inner diameter side are arranged in the circumferential direction. The plurality of protrusions 57 are formed in correspondence with a plurality of recesses 51a of the outer peripheral surface of the output shaft portion 51, and the output shaft portion 51 and the cylindrical portion 52 (the resin portion 56) are firmly fixed by the engagement of these protrusions 57 and the recesses 51a, thereby suppressing the mutual movement in the radial and axial directions.

[0051] The end portion of the input side in the resin portion 56 supports the bearing support ring 55 at the outer peripheral portion thereof.

[0052] Figure 3 is a cross-sectional view of the magnetic modulation body 50 as a single piece.

[0053] As shown in the drawing, the portion of the resin portion 56 located on the output side of the intermediate magnetic pole body 54 (the magnetic pole piece 54a) exposes the end surface 54c of the output side of the magnetic pole piece 54a over the entire circumferential direction. Therefore, it is possible to bring a measuring device into contact with this exposed end surface 54c, and thus it is possible to directly measure the axial position of this end surface 54c. As a result, it is possible to more accurately manage the relative axial positions of the intermediate magnetic pole body 54 (the magnetic pole piece 54a) with respect to the outer magnetic pole body 12 and the inner magnetic pole body 41a.

[0054] Here, the relative axial position of the intermediate magnetic pole body 54 with respect to the inner magnetic pole body 41a is defined by the axial dimension between the shoulder surface 51b contacted by the inner ring of the bearing 64 supporting the input shaft 40 and the end surface 54c of the magnetic pole piece 54a. Also, the relative axial position of the intermediate magnetic pole body 54 with respect to the outer magnetic pole body 12 is defined by the axial dimension between the shoulder surface 55a contacted by the inner ring of the bearing 61 or the shoulder surface 51c contacted by the inner ring of the bearing 63 and the end surface 54c of the magnetic pole piece 54a. If necessary, these shoulder surfaces can be machined or shims can be inserted at the time of assembly to adjust the axial position of the intermediate magnetic pole body 54. However, the above axial dimensions are dimensions in the single piece of the magnetic modulation body 50, and it goes without saying that the relative axial position of the magnetic modulation body 50 is affected by the axial position of the outer rings of the bearings 61 to 64. The axial position of the intermediate magnetic pole body 54 can be appropriately adjusted in consideration of the axial position of the outer rings of the bearings 61 to 64.

[0055] Also, it is sufficient that at least one of the two end surfaces in the axial direction of the magnetic pole piece 54a is exposed. For example, as shown in FIG. 6, both of the two end surfaces 54c, 54c in the axial direction of the magnetic pole piece 54a can be exposed. Or, as shown in FIG. 7, only a part of the end surface 54c of the magnetic pole piece 54a in the circumferential direction can be exposed. Figure 4 Figure 5 Figure 5 In the example of FIG. 7, the end surface 54c of the magnetic pole piece 54a is exposed to the output side through the plurality of hole portions 56a formed in the resin portion 56. The plurality of hole portions 56a are, for example, axial circular holes of a size that allows easy insertion of a measurement probe, and are arranged equidistantly along the circumference.

[0056] Also, with respect to the end surface 54c in the axial direction of the magnetic pole piece 54a, from the viewpoint of easy measurement, it is preferable that the outer circumferential side portion is exposed rather than the inner circumferential side portion. Specifically, when the outer circumferential side portion is exposed, the area of the portion to be measured is larger, and it is easier to secure the surrounding work space (it is easier to work). If only the inner circumferential side portion is slightly exposed, it is difficult to perform measurement. Also, for example, when the inner diameter side portion in the input side end surface is exposed, in order to measure the axial dimension between the end surface and the shoulder surface (for example, the shoulder surface 51c) of the outer diameter side, it is not possible to directly measure the distance between the two surfaces by the measurement device, and it is necessary to indirectly measure via a reference position further to the input side than the magnetic modulation body 50, and thus it is possible to increase the error.

[0057] Also, the "exposure" of the end surface 54c of the magnetic pole piece 54a means that the end surface 54c is not covered by the resin (the resin portion 56) that integrates the magnetic pole piece 54a and the support portion (the output shaft portion 51, the bearing support ring 55). Therefore, for example, the coating of the magnetic pole piece (electromagnetic steel sheet) and the like is not included in the resin, and thus the presence or absence of the coating and the like does not affect the "exposure" of the end surface 54c according to the present embodiment.​​

[0058] [Action of the magnetically modulated gear]

[0059] like Figure 1 and Figure 2 As shown, in the magnetic modulation gear 1, if the input shaft 40 is rotated around the central axis Ax by a motor (not shown), the spatial magnetic flux waveform formed by the inner magnetic pole 41a (inner magnet 41b) of the input shaft 40 is modulated by the intermediate magnetic pole 54 (magnetic pole piece 54a) to the same frequency as the outer magnetic pole 12 (outer magnet 12a). Then, the magnetic force between the intermediate magnetic pole 54 and the outer magnetic pole 12 is used to transmit torque to the magnetic modulator 50. In this way, the rotational motion input to the input shaft 40 is decelerated and output to the driven component (omitted in the figure) connected to the output shaft 51 of the magnetic modulator 50.

[0060] Alternatively, the intermediate magnetic pole 54 can be fixed, and the outer magnetic pole 12 can be placed on a rotatable low-speed rotor and output from the low-speed rotor.

[0061] Here, the reduction ratio R of the magnetic modulation gear 1 is expressed by the following formula (1) when the output shaft is the middle magnetic pole 54, and by the following formula (2) when the output shaft is the outer magnetic pole 12.

[0062] R=Np / Ni…(1)

[0063] R=No / Ni…(2)

[0064] Wherein, Np is the number of magnetic poles of the middle magnetic pole body 54 (number of magnetic pole pieces 54a: number of magnetic pole pieces), No is the number of pole pairs of the outer magnet 12a (number of outer pole pairs), and Ni is the number of pole pairs of the inner magnetic pole body 41a (number of inner pole pairs).

[0065] Furthermore, the following relationship (3) holds between the number of magnetic pole pieces Np, the number of outer pole pairs No, and the number of inner pole pairs Ni.

[0066] Np=Ni+No…(3)

[0067] [Manufacturing Process of Magnetic Modulators]

[0068] Figure 6 This is a flowchart showing the general manufacturing process of the magnetic modulator 50. Figure 7 This is a cross-sectional view showing the state in which the magnetic pole pieces 54a and the like are arranged in the molding die during the molding of the resin part 56.

[0069] like Figure 6As shown, in the manufacturing process of the magnetic modulation body 50, first, the output shaft portion 51 and the bearing support ring 55 are machined (step S1). Here, both the output shaft portion 51 and the bearing support ring 55 are machined to a prescribed finished shape by machining or the like (in addition to machining, necessary treatments such as heat treatment, surface treatment, etc. are included).

[0070] Next, the intermediate magnetic pole body 54 (magnetic pole piece 54a) is machined (step S2). Here, after one (or more) electromagnetic steel sheets are punched into the planar shape of the magnetic pole piece 54a, they are stacked to a prescribed axial length, thereby manufacturing the magnetic pole piece 54a. The number of magnetic pole pieces 54a required for manufacturing is manufactured. Alternatively, the magnetic pole piece 54a can be manufactured by another method such as wire cutting without being punched.

[0071] Next, the output shaft portion 51, the bearing support ring 55, and the intermediate magnetic pole body 54 (the plurality of magnetic pole pieces 54a) manufactured by steps S1 and S2 are arranged in a molding die for molding the resin portion 56 (step S3: arrangement process).

[0072] Specifically, as shown, Figure 7 first, the output shaft portion 51, the bearing support ring 55, and the plurality of magnetic pole pieces 54a are arranged on a first molding die 71 of a prescribed outer diameter side shape. At this time, the first molding die 71 is in contact (abuts) with the output side end surface 54c of the magnetic pole piece 54a.

[0073] Subsequently, a second molding die 72 of a prescribed inner diameter side shape is arranged on the input side of the output shaft portion 51.

[0074] Next, resin is filled in the first molding die 71 and the second molding die 72 in which the output shaft portion 51, the bearing support ring 55, and the plurality of magnetic pole pieces 54a are arranged, and molding (resin transfer molding or injection molding, etc.) of the resin portion 56 is performed (step S4: molding process).

[0075] Specifically, the resin is filled in the filling space S indicated by a dot in Figure 7 to mold the resin portion 56. The output shaft portion 51, the bearing support ring 55, and the plurality of magnetic pole pieces 54a are fixed to each other by the resin portion 56 and integrated.

[0076] At this time, since the first molding die 71 has a portion in contact with the output side end surface 54c of the magnetic pole piece 54a, the portion of the end surface 54c in contact with the first molding die 71 is not covered with resin and exposed at the time of molding.

[0077] Next, the inner circumferential surface and the outer circumferential surface of the intermediate magnetic pole body 54 are finished (step S5). Here, the inner circumferential surface and the outer circumferential surface of the intermediate magnetic pole body 54 are machined to a prescribed shape accuracy or the like by a lathe or a grinder. Thus, the accuracy of the centering of the inner circumferential surface or the outer circumferential surface is improved, and the loss or torque ripple during operation is improved.

[0078] In addition, here, at least one of the inner circumferential surface and the outer circumferential surface of the intermediate magnetic pole body 54 can be machined. Also, other portions can be machined. Also, the machining here is not limited to machining by a lathe or a grinder, and includes, for example, hand grinding or the like. Also, the machining of step S5 can not be performed.

[0079] [Technical Effects of the Present Embodiment]

[0080] As described above, according to the present embodiment, at least one of the two end surfaces 54c in the axial direction in the magnetic pole piece 54a is exposed.

[0081] Thus, the axial position of the exposed end surface 54c can be directly measured. Therefore, the relative axial position of the magnetic pole piece 54a (intermediate magnetic pole body 54) with respect to the outer magnetic pole body 12 and the inner magnetic pole body 41a can be easily managed. Even the assembly work of the magnetic modulation gear 1 can be easily performed, and performance deterioration due to a shift in the axial position of the magnetic modulation body 50 can be suppressed.

[0082] In addition, according to the present embodiment, the two end surfaces 54c in the axial direction in the magnetic pole piece 54a can be exposed.

[0083] At this time, the axial positions of the two end surfaces 54c can be measured. Therefore, compared to a case in which only one of the end surfaces 54c is exposed, the axial position of the magnetic pole piece 54a can be more accurately managed.

[0084] In addition, according to the present embodiment, the end surface 54c of the magnetic pole piece 54a can be exposed via the hole portion 56a of the resin portion 56.

[0085] At this time, compared to a case in which the end surface 54c is exposed over the entire circumferential direction, the area of the exposed end surface 54c is reduced. Therefore, although the measurement convenience of the end surface 54c can be affected compared to a case in which the end surface 54c is exposed over the entire circumferential direction, the holding rigidity of the resin portion 56 with respect to the magnetic pole piece 54a can be improved.

[0086] [Other]

[0087] The embodiments of the present application have been described above, but the present application is not limited to the above-described embodiments.

[0088] For example, in the above-described embodiment, in the step S3 (arranging process) of arranging the magnetic pole piece and the support portion in the molding die, at least one of the two end surfaces in the axial direction of the magnetic pole piece is brought into contact with the molding die, thereby causing the end surface to be exposed. That is, the magnetic modulation body according to the present embodiment has the end surface of the magnetic pole piece in the axial direction exposed from the resin portion immediately after the molding process of step S4 is completed. Therefore, a product in which the exposed end surface of the magnetic pole piece is covered with other resin after the molding process is also included in the magnetic modulation body according to the present embodiment. At this time, even if the resin portion molded in the molding process and the other resin added to cover the end surface are of the same kind, a boundary line or the like, a remolding mark, is formed, and thus it is considered to be identifiable.

[0089] Further, the detailed structure shown in the above-described embodiment can be appropriately changed within a range not departing from the gist of the present application.

Claims

1. A magnetic modulator comprising: Magnetic pole pieces; A support portion, arranged along the axial direction of the magnetic pole piece, and used for rotatably supporting the magnetic pole piece; and The resin section integrates the magnetic pole piece with the support section. At least one of the two end faces of the magnetic pole piece is exposed along its axial direction.

2. The magnetic modulator according to claim 1, wherein, The two end faces of the magnetic pole piece are exposed along its axial direction.

3. The magnetic modulator according to claim 1, wherein, The resin portion has a hole formed along the axial direction. At least one of the two end faces of the magnetic pole piece along its axial direction is exposed through the hole.

4. A magnetically modulated gear, comprising: The magnetic modulator according to any one of claims 1 to 3; An input shaft is disposed on the inner diameter side of the magnetic modulator and has a plurality of inner magnets arranged circumferentially; and Multiple outer magnets are disposed on the outer diameter side of the magnetic modulator and arranged circumferentially.

5. A method for manufacturing a magnetic modulator, comprising: In the configuration process, the magnetic pole piece and the support portion for rotating and supporting the magnetic pole piece are configured in the forming mold; and In the molding process, resin is filled into the molding mold in which the magnetic pole piece and the support portion are disposed, and a resin portion integrating the magnetic pole piece and the support portion is formed. In the configuration process, at least one of the two axial end faces of the magnetic pole piece is brought into contact with the forming mold.

Images