Magnetic modulator, magnetic modulator gear, method for manufacturing a magnetic modulator

Abstract

To make it easier to control the axial position of the magnetic pole pieces. [Solution] The magnetic modulator 50 comprises a magnetic pole piece 54a, an output shaft portion 51 and a bearing support ring 55 arranged in the axial direction of the magnetic pole piece 54a for rotationally supporting the magnetic pole piece 54a, and a resin portion 56 that integrates the magnetic pole piece 54a with the output shaft portion 51 and the bearing support ring 55. At least one of the axial end faces of the magnetic pole piece 54a is exposed. This allows the axial position of the exposed end face 54c of the magnetic pole piece 54a to be measured directly.

Description

Technical Field

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[0001] The present invention relates to a magnetic modulation body, a magnetic modulation gear, and a method for manufacturing a magnetic modulation body.

Background Art

[0002] Conventionally, a magnetic modulation gear is known in which a magnetic modulation body having a plurality of magnetic pole pieces is disposed between two magnet rotors disposed on the inner and outer circumferences, and the magnetic flux distribution between the two magnet rotors is modulated (see, for example, Patent Document 1). In the magnetic modulation body, the magnetic pole piece and the support portion for rotatably supporting the magnetic pole piece are integrated with resin. The support portion is disposed in the axial direction of the magnetic pole piece, and the end face in the axial direction of the magnetic pole piece is connected to the support portion via resin. [[ID=,16]]

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the magnetic modulation body, since the end face in the axial direction of the magnetic pole piece is covered with resin, it is difficult to manage the relative axial position between the magnet disposed on the inner and outer circumferences and the magnetic pole piece. When the axial positions of the magnetic pole piece and the magnet are displaced, torque reduction due to leakage magnetic flux and thrust force toward the magnetic stable position are generated, and the performance deteriorates.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to make it easy to manage the axial position of the magnetic pole piece.

Means for Solving the Problems

[0006] The present invention is a magnetic modulation body, a magnetic pole piece, A support portion is arranged in the axial direction of the magnetic pole piece and is used to support the rotation of the magnetic pole piece. A resin part that integrates the magnetic pole piece and the support part, Equipped with, The aforementioned pole piece has at least one of its axial end faces exposed. [Effects of the Invention]

[0007] According to the present invention, the axial position of the magnetic pole pieces can be easily controlled. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a magnetic modulation gear according to an embodiment. [Figure 2] This is a cross-sectional view taken along line III-III in Figure 1. [Figure 3] This is a cross-sectional view of a magnetic modulator according to an embodiment. [Figure 4] This is a cross-sectional view of a modified example of the magnetic modulator according to the embodiment. [Figure 5] This is a diagram showing a modified example of the magnetic modulator according to the embodiment, viewed from the output side. [Figure 6] This is a flowchart illustrating the general manufacturing process of a magnetic modulator according to the embodiment. [Figure 7] This is a cross-sectional view showing the state in which magnetic pole pieces and the like are positioned in the mold during the molding of the resin part. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0010] [Overall configuration of magnetic modulation gear] Figure 1 is a cross-sectional view of the magnetic modulation gear 1 according to this embodiment, and Figure 2 is a cross-sectional view taken along line III-III in Figure 1. In the following explanation, the direction along the central axis Ax of the magnetic modulation gear 1 is referred to as the "axial direction," the direction perpendicular to the central axis Ax is referred to as the "radial direction," and the rotational direction around the central axis Ax is referred to as the "circumferential direction." Furthermore, within the axial direction, the side connected to the external driven member (left side in Figure 1) is referred to as the "output side," and the opposite side (right side in Figure 1) is referred to as the "input side."

[0011] As shown in Figures 1 and 2, the magnetic modulation gear 1 according to this embodiment comprises a casing (frame) 10, an input-side cover 20 and an output-side cover 30 that cover both sides of the casing 10 in the axial direction, and an input shaft 40 and a magnetic modulator 50 whose main parts are housed inside these covers.

[0012] The casing 10 is formed in a substantially cylindrical shape with a central axis Ax at its center, and has a stator yoke 11 and an outer magnetic pole body 12 on its inner circumference. The stator yoke 11 is formed in a cylindrical shape and is fitted inside the casing 10. The outer pole body 12 is composed of a plurality of outer magnets 12a. The plurality of outer magnets 12a are permanent magnets such as neodymium magnets, and have a greater number of pole pairs than the inner magnets 41b of the input shaft 40, which will be described later. They are attached to the inner surface of the stator yoke 11 so that magnets with different polarities are arranged alternately in the circumferential direction. However, the outer pole body 12 may be a single ring shape, or it may be made of divided outer magnets 12a arranged in the circumferential direction. Furthermore, a bearing 61 (for example, a ball bearing) is positioned on the inner circumference of the casing 10 on the input side of the stator yoke 11 to rotatably support the magnetic modulator 50.

[0013] The input-side cover 20 is positioned on the input side of the casing 10 and covers the inner opening of the casing 10 from the input side. The outer circumference of the input-side cover 20 is fitted with the casing 10 using a spigot joint. A bearing 62 (for example, a ball bearing) that rotatably supports the input shaft 40 is positioned on the inner circumference of the input-side cover 20.

[0014] The output-side cover 30 is disposed on the output side of the casing 10 and covers the inner opening of the casing 10 from the output side. The outer peripheral portion of the output-side cover 30 is fitted with the casing 10 by an inlay. Also, a bearing 63 (for example, a ball bearing) that rotatably supports the magnetic modulation body 50 is disposed on the inner peripheral portion of the output-side cover 30.

[0015] The input shaft 40 is a shaft that rotates around the central axis Ax and includes a disk portion 41 and a motor connection portion 42. This input shaft 40 is rotatably supported by a bearing 62 disposed between the input-side cover 20 and a bearing 64 disposed between the magnetic modulation body 50. The motor connection portion 42 extends axially to the input side from the disk portion 41. The tip side of the motor connection portion 42 protrudes outside from the input-side cover 20, and this protruding portion is connected to a motor (not shown).

[0016] The disk portion 41 has an inner magnetic body 41a disposed on the inner diameter side of the outer magnetic body 12 on its outer peripheral portion. The inner magnetic 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 disk portion 41 so that those with different polarities are alternately arranged in the circumferential direction. However, the inner magnetic body 41a may be an integral ring shape or may be, for example, a structure in which the divided inner magnets 41b are arranged in the circumferential direction.

[0017] [Configuration of Magnetic Modulation Body] As shown in FIGS. 1 and 2, the magnetic modulation body 50 has an output shaft portion 51, a cylindrical portion 52, and a bearing support ring 55. Among these, the output shaft portion 51 and the bearing support ring 55 are an example of a support portion according to the present invention and are portions for rotatably supporting an intermediate magnetic body 54 (magnetic pole piece 54a) described later.

[0018] The output shaft portion 51 is a metal shaft that rotates around the central axis Ax and is disposed on the output side of the intermediate magnetic body 54 described later. Approximately half of the output shaft portion 51 on the output side protrudes outside from the output-side cover 30, and this protruding portion is connected to a driven member (not shown). The output shaft portion 51 is rotatably supported by a bearing 63 positioned between it and the output side cover 30, approximately in the axial direction. Furthermore, a bearing 64 (e.g., a ball bearing) is positioned at the input side end of the output shaft portion 51 to rotatably support the input shaft 40. The output side end of the cylindrical portion 52 is connected to the outer circumference of the output shaft portion 51 at the axial position between the bearing 63 and the bearing 64.

[0019] The bearing support ring 55 is made of metal (for example, stainless steel) and is positioned on the input side of the intermediate magnetic pole body 54, which will be described later. The bearing support ring 55 is fixed to the outer circumference of the input end of the cylindrical portion 52, and the inner ring of the bearing 61, which is positioned between the bearing support ring 55 and the casing 10, is fitted onto its outer surface.

[0020] The cylindrical portion 52 is formed in a substantially cylindrical shape with respect to the central axis Ax and has an intermediate magnetic pole body 54 positioned in the axial direction corresponding to the outer magnetic pole body 12 and the inner magnetic pole body 41a. The intermediate magnetic pole body 54 has a plurality of magnetic pole pieces 54a. Multiple pole pieces 54a are arranged at predetermined intervals in the circumferential direction, forming an annular shape as a whole. The multiple pole pieces 54a (intermediate pole body 54) are arranged concentrically on the inner diameter side of the outer pole body 12 and on the outer diameter side of the inner pole body 41a, with predetermined gaps between them. Each pole piece 54a is constructed by stacking thin electromagnetic steel sheets (laminated steel sheets) in the axial direction.

[0021] Adjacent magnetic pole pieces 54a in the circumferential direction are connected by connecting portions 54b between them. The connecting portion 54b is made of resin and constitutes part of the resin portion 56, which will be described later. The outer surface of the connecting portion 54b is recessed toward the inner diameter side compared to the outer surface of the magnetic pole piece 54a. However, the inner and outer surfaces of the connecting portion 54b may be flush with the corresponding surface of the magnetic pole piece 54a, or the inner surface may be recessed toward the outer diameter. Furthermore, the connecting portion 54b may be integrally formed with the magnetic pole piece 54a using an electromagnetic steel sheet. In this case, the radial position and width of the connecting portion 54b are not particularly limited, but may be configured to obtain suitable torque performance, for example, as described in International Publication No. 2023 / 026804.

[0022] Of the cylindrical portion 52, the portion excluding the magnetic pole pieces 54a is a resin portion 56 made of resin (for example, super engineering plastic). In other words, of the magnetic modulator 50, the portion excluding the output shaft portion 51, the bearing support ring 55, and the intermediate magnetic pole body 54 (multiple magnetic pole pieces 54a) is the resin portion 56. Resin is also filled between the multiple magnetic pole pieces 54a, and this portion constitutes the aforementioned connecting portion 54b. The output end of the resin portion 56 protrudes inward and is connected to the output shaft portion 51. Multiple protrusions 57 are arranged circumferentially on the inner circumference of this end, projecting inward. These multiple protrusions 57 are molded to correspond to multiple recesses 51a on the outer surface of the output shaft portion 51. The engagement of these protrusions 57 and recesses 51a firmly fixes the output shaft portion 51 and the cylindrical portion 52 (resin portion 56), suppressing mutual movement in the radial and axial directions. The input-side end of the resin part 56 supports a bearing support ring 55 on its outer circumference.

[0023] Figure 3 is a cross-sectional view of the magnetic modulator 50 alone. As shown in this figure, in the resin part 56, the portion located on the output side of the intermediate magnetic pole body 54 (magnetic pole piece 54a) has the output end face 54c of the magnetic pole piece 54a exposed over its entire circumference. Therefore, by bringing a measuring instrument into contact with the exposed end face 54c, the axial position of the end face 54c can be measured directly. This allows for more accurate control of the relative axial position of the intermediate magnetic pole body 54 (magnetic pole piece 54a) with respect to the outer magnetic pole body 12 and the inner magnetic pole body 41a. Here, the relative axial position of the intermediate pole body 54 with respect to the inner pole body 41a is defined by the axial dimension between the shoulder surface 51b of the bearing 64 supporting the input shaft 40, which contacts the inner ring, and the end surface 54c of the pole piece 54a. Similarly, the relative axial position of the intermediate pole body 54 with respect to the outer pole body 12 is defined by the axial dimension between the shoulder surface 55a of the bearing 61, or the shoulder surface 51c of the bearing 63, which contacts the inner ring, and the end surface 54c of the pole piece 54a. The axial position of the intermediate pole body 54 can be adjusted by machining these shoulder surfaces or inserting shims during assembly as needed. However, the axial dimensions described above are for the magnetic modulator 50 alone, and it goes without saying that the axial position of the outer rings of the bearings 61-64 affects the relative axial position of the magnetic modulator 50. The axial position of the intermediate pole body 54 should be adjusted appropriately, taking into account the axial position of the outer rings of the bearings 61-64.

[0024] Note that the magnetic pole piece 54a only needs to have at least one of its axial end faces exposed. For example, as shown in Figure 4, both axial end faces 54c, 54c of the magnetic pole piece 54a may be exposed. Alternatively, as shown in Figure 5, only a portion of the end face 54c of the magnetic pole piece 54a in the circumferential direction may be exposed. In the example in Figure 5, the end face 54c of the magnetic pole piece 54a is exposed on the output side through a plurality of holes 56a formed in the resin part 56. The plurality of holes 56a are, for example, axial circular holes of a size that allows a measuring probe to be inserted without difficulty, and are arranged equally on the circumference. Furthermore, it is preferable for the outer circumference portion of the axial end face 54c of the magnetic pole piece 54a to be exposed rather than the inner circumference portion, in terms of ease of measurement. Specifically, if the outer circumference portion is exposed, the area of ​​the portion to be measured is larger, and a wider working space can be secured around it (making it easier to work). If only a small portion of the inner circumference portion is exposed, measurement becomes difficult. Also, for example, if the inner diameter portion of the input end face is exposed, in order to measure the axial dimension between that end face and the outer diameter shoulder surface (e.g., shoulder surface 51c), depending on the measuring instrument, the distance between these two surfaces cannot be measured directly, and the measurement becomes indirect, via a reference position on the input side of the magnetic modulator 50, which may increase the error. Furthermore, "exposed" end face 54c of the pole piece 54a means that the end face 54c is not covered by the resin (resin part 56) that integrates the pole piece 54a with the support part (output shaft part 51, bearing support ring 55). Therefore, since coatings on the pole piece (electromagnetic steel sheet), for example, are not included in the resin, the presence or absence of such coatings does not affect the "exposure" of the end face 54c according to this embodiment.

[0025] [Operation of magnetic modulation gear] As shown in Figures 1 and 2, in the magnetic modulation gear 1, when the input shaft 40 rotates around the central axis Ax by a motor (not shown), the spatial magnetic flux waveform formed by the inner magnetic pole body 41a (inner magnet 41b) of the input shaft 40 is modulated to the same frequency as the outer magnetic pole body 12 (outer magnet 12a) by the intermediate magnetic pole body 54 (magnetic pole piece 54a). Then, rotational torque is transmitted to the magnetic modulator 50 using the magnetic force between the intermediate magnetic pole body 54 and the outer magnetic pole body 12. In this way, the rotational motion input to the input shaft 40 is reduced and output to a driven member (not shown) connected to the output shaft portion 51 of the magnetic modulator 50. Alternatively, the intermediate pole body 54 may be fixed, and the outer pole body 12 may be mounted on a rotatable low-speed rotor, from which the output may be taken.

[0026] Here, the reduction ratio R of the magnetic modulation gear 1 is expressed by the following equation (1) when the output shaft is the intermediate magnetic pole body 54, and by the following equation (2) when the output shaft is the outer magnetic pole body 12. R = Np / Ni ... (1) R = No / Ni ···(2) However, Np is the number of poles of the intermediate pole body 54 (number of pole pieces 54a: number of 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 pole body 41a (number of inner pole pairs). Furthermore, the following relationship (3) holds between the number of pole segments Np, the number of outer pole pairs No, and the number of inner pole pairs Ni. Np = Ni + No ···(3)

[0027] [Manufacturing process for magnetic modulators] Figure 6 is a flowchart showing the general manufacturing process of the magnetic modulator 50. Figure 7 is a cross-sectional view showing the state in which the magnetic pole pieces 54a and the like are placed in the mold when the resin part 56 is being molded. As shown in Figure 6, in the manufacturing process of the magnetic modulator 50, the output shaft portion 51 and the bearing support ring 55 are first processed (step S1). Here, both the output shaft portion 51 and the bearing support ring 55 are machined or otherwise processed (including necessary treatments such as heat treatment and surface treatment in addition to machining) to a predetermined finished shape.

[0028] Next, the intermediate pole body 54 (pole piece 54a) is processed (step S2). Here, one (or more) electromagnetic steel sheets are punched out into the planar shape of the pole piece 54a, and then these are stacked for a predetermined axial length to produce the pole piece 54a. Only the required number of pole pieces 54a are produced. Note that the pole pieces 54a may also be produced by wire cutting or other methods instead of punching.

[0029] Next, the output shaft portion 51, bearing support ring 55, and intermediate magnetic pole body 54 (multiple magnetic pole pieces 54a) manufactured in steps S1 and S2 are placed in a mold for forming the resin portion 56 (step S3: placement step). Specifically, as shown in Figure 7, first, the output shaft portion 51, the bearing support ring 55, and a plurality of magnetic pole pieces 54a are placed on the first molding die 71 which defines the shape of the outer diameter side. At this time, the first molding die 71 is in contact with (abuts against) the output end face 54c of the magnetic pole piece 54a. Next, the second mold 72, which defines the shape of the inner diameter, is set on the input side of the output shaft 51.

[0030] Next, resin is filled into the first mold 71 and the second mold 72, in which the output shaft portion 51, the bearing support ring 55, and the plurality of magnetic pole pieces 54a are arranged, and the resin portion 56 is molded (resin casting or injection molding, etc.) (Step S4: Molding process). Specifically, resin is filled into the filling space S shown by dots in Figure 7 to form the resin part 56. This resin part 56 fixes and integrates the output shaft 51, the bearing support ring 55, and the multiple magnetic pole pieces 54a with each other. At this time, since the first mold 71 has a portion that contacts the output end face 54c of the magnetic pole piece 54a, the portion of the end face 54c that was in contact with the first mold 71 is exposed after molding and is not covered with resin.

[0031] Next, the inner and outer surfaces of the intermediate magnetic pole body 54 are finished (step S5). Here, the inner and outer surfaces of the intermediate magnetic pole body 54 are machined to a predetermined shape accuracy using a lathe or grinding machine. This improves the centering accuracy of these inner and outer surfaces, reducing losses and torque ripple during operation. In this step, it is sufficient for at least one of the inner and outer surfaces of the intermediate magnetic pole body 54 to be machined. Other parts may also be machined. Furthermore, the machining here is not limited to machining with a lathe or grinding machine, but also includes, for example, manual polishing. Also, the machining in step S5 is not required.

[0032] [Technical effects of this embodiment] As described above, according to this embodiment, at least one of the axial end faces 54c of the magnetic pole piece 54a is exposed. This allows for direct measurement of the axial position of the exposed end face 54c. Therefore, it becomes easier to manage the relative axial position of the pole piece 54a (intermediate pole body 54) with respect to the outer pole body 12 and the inner pole body 41a. Consequently, the assembly of the magnetic modulation gear 1 is made easier, and performance deterioration due to axial misalignment of the magnetic modulator 50 can be suppressed.

[0033] Furthermore, according to this embodiment, both axial end faces 54c of the magnetic pole piece 54a may be exposed. In this case, the axial positions of both end faces 54c can be measured. Therefore, the axial position of the magnetic pole piece 54a can be controlled more accurately compared to the case where only one end face 54c is exposed.

[0034] Furthermore, according to this embodiment, the end face 54c of the magnetic pole piece 54a may be exposed through the hole 56a of the resin part 56. In this case, the area of ​​the exposed end face 54c is reduced compared to the case where the end face 54c is exposed around its entire circumference. Therefore, although the ease of measuring the end face 54c may be impaired compared to the case where the end face 54c is exposed around its entire circumference, the holding rigidity of the magnetic pole piece 54a by the resin part 56 can be improved.

[0035] [others] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. For example, in the above embodiment, in step S3 (arrangement step) in which the pole piece and support part are placed in the mold, the end face is exposed by bringing at least one of the axial end faces of the pole piece into contact with the mold. That is, in the magnetic modulator according to this embodiment, the axial end face of the pole piece is exposed from the resin part immediately after the molding step in step S4. Therefore, a magnetic modulator according to this embodiment in which the exposed end face of the pole piece is covered with another resin after this molding step is included. In this case, the resin part molded in the molding step and the other resin added to cover the end face are considered to be distinguishable because remolding marks such as boundary lines are formed, even if they are of the same type.

[0036] Furthermore, details shown in the above embodiments can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0037] 1. Magnetic modulation gear 12 Outer pole body 12a outer magnet 41a Inner pole body 41b Inner magnet 50 Magnetic modulator 51 Output shaft section (support section) 54 Intermediate magnetic pole body 54a pole piece 54b Connection part 55 Bearing support ring (support part) 56 Resin part 56a Hole 71 1st mold 72 Second molding Ax Central Axis S Fill Space

Claims

1. Magnetic pole pieces and, A support portion is arranged in the axial direction of the magnetic pole piece and is used to support the rotation of the magnetic pole piece. A resin part that integrates the magnetic pole piece and the support part, Equipped with, The aforementioned pole piece has at least one of its axial end faces exposed. Magnetic modulator.

2. The aforementioned pole piece has both axial end faces exposed. The magnetic modulator according to claim 1.

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

4. A magnetic modulator according to any one of claims 1 to 3, An input shaft having a plurality of inner magnets arranged circumferentially on the inner diameter side of the magnetic modulator, A plurality of outer magnets are arranged on the outer diameter side of the magnetic modulator and are arranged in the circumferential direction, A magnetic modulation gear equipped with [a specific feature].

5. A placement step of arranging a magnetic pole piece and a support part for rotatably supporting the magnetic pole piece in a mold, A molding step in which resin is filled into the mold in which the magnetic pole piece and the support part are arranged, and a resin part is formed that integrates the magnetic pole piece and the support part, Equipped with, In the arrangement step, at least one of the axial end faces of the magnetic pole piece is brought into contact with the mold. A method for manufacturing a magnetic modulator.

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