Hub housing, rotor and bicycle hub dynamo

Abstract

Rotor for a bicycle hub dynamo, comprehensive: a hub housing with a base body having a tubular shape with an inner circumferential surface, and a magnet arrangement section which is provided on the inner circumferential surface of the base body for the arrangement of a magnet formed therein by injection molding, wherein the magnet assembly section is provided in an axial central section of the inner circumferential surface of the base body such that the magnet assembly section faces a coil which is arranged radially within the magnet assembly section when the rotor is installed in the bicycle hub dynamo; and a magnet formed by injection molding in the magnet assembly section of the hub housing; wherein the magnet is a bonded magnet made from a mixture of magnetic powder and a synthetic resin; wherein the magnet arrangement section comprises a planar section and a non-planar section, wherein the non-planar section is configured as one of a depression and a projection with respect to the planar section, wherein the non-planar section has a linear shape and extends non-parallel with respect to the axial direction and the circumferential direction of the base body respectively, and wherein part of the magnet enters the non-planar section when the magnet is injection molded.

Description

BACKGROUNDField of the invention

[0001] This invention generally relates to a hub shell for a bicycle hub dynamo and a hub dynamo equipped with the hub shell. Background information

[0002] A bicycle hub dynamo with a magnet arranged on the inner peripheral surface of a bicycle hub shell is known (e.g., Japanese Laid-Open Patent Publication JP 2004-242374 A). Typically, the magnet is attached to the inner peripheral surface of the hub shell with an adhesive.

[0003] DE 42 32 182 A1 discloses a hub alternator with several cuboid-shaped individual magnets that are glued or positively attached to the inside of the rotor.

[0004] DE 197 14 780 A1 discloses a rotor for an electric motor whose inner, rotating hub is overmolded with a magnet on its outer surface. Further prior art publications include DE 600 29 717 T2, WO 99 / 12 248 A1, JP H08-106 711 A, JP 2006-180 576 A, and JP H08-23 649 A. SUMMARY

[0005] In general, the present disclosure is directed to various features of a hub shell for a bicycle hub dynamo.

[0006] If the magnet is attached with an adhesive in the conventional manner, a step for applying the adhesive and a step for attaching the magnet are required, and the process for attaching the magnet to the hub shell becomes complex. To simplify the magnet attachment process, the magnet is conveniently formed on the inner peripheral surface of the hub shell by injection molding or other molding methods. However, when using the injection molding method to form the magnet on the inner peripheral surface of the hub shell, positioning the magnet was difficult.

[0007] An object of the present invention is to enable a magnet injection-molded in a hub shell for a hub dynamo to be formed more easily and positioned more securely.

[0008] According to a first aspect, a hub shell is provided that is used as a part of a bicycle hub dynamo. The hub shell basically comprises a base body and a magnet arranging portion. The base body has a tubular shape with an inner peripheral surface. The magnet arranging portion is provided on the inner peripheral surface of the base body so that a magnet formed therein by injection molding can be arranged. The magnet arranging portion comprises a flat portion and a non-flat portion, wherein the non-flat portion is configured as one of a recess and a projection relative to the flat portion.

[0009] With this hub shell, the magnet assembly section, into which the magnet is injection-molded, includes a flat section and a non-flat section. If the non-flat section is a recess, the magnet can be easily and securely positioned by injection-molding the magnet so that a portion of the magnet fits into the non-flat section. If the non-flat section is a protrusion, the magnet can be easily and securely positioned by injection-molding the magnet so that a portion of the magnet fits around the non-flat section.

[0010] According to a second aspect, the hub shell according to the first aspect is provided such that the non-planar portion is configured as a linear shape and extends non-parallel to each of the axial direction and the circumferential direction of the main body. Since, with this aspect, the linearly shaped non-planar portion extends non-parallel to each of the axial and circumferential directions, the movement of the magnet in both the axial and circumferential directions can be restricted, and the magnet can be positioned easily and securely.

[0011] According to a third aspect, the hub shell according to the second aspect is provided such that the non-planar portion has a helical shape. Since, with this aspect, the non-planar portion has a continuous helical shape, the non-planar portion can be easily obtained.

[0012] According to a fourth aspect, the hub shell according to the second aspect is provided such that the non-planar portion has a continuous shape. Since, with this aspect, the non-planar portion has a continuous shape and can be formed with only one process, the non-planar portion can be easily obtained.

[0013] According to a fifth aspect, the hub shell according to the fourth aspect is provided such that the non-planar portion comprises a plurality of separate non-planar portions. Since the non-planar portions have continuous shapes, the magnet can be positioned even more securely.

[0014] According to a sixth aspect, the hub shell according to the first aspect is provided such that the non-planar portion includes a first non-planar portion having a linear shape and extending in the axial direction of the main body, and a second non-planar portion having a linear shape and extending in the circumferential direction of the main body. Since the shape of the non-planar portion is simple in this aspect, the non-planar portion can be easily formed.

[0015] According to a seventh aspect, the hub shell according to any one of the first to sixth aspects is provided such that the non-planar portion is configured as a recess. With this aspect, the recessed non-planar portion can be formed with a simple machining process (cutting process).

[0016] According to an eighth aspect, the hub shell according to any one of the first to sixth aspects is provided such that the non-planar portion is configured as a protrusion. With this aspect, the protruding non-planar portion can be easily formed as a separate member from the hub shell. Thus, the non-planar portion can be easily formed using a molding process.

[0017] According to a ninth aspect, the hub shell according to any one of the first to eighth aspects is equipped with a magnet injection-molded onto the magnet arrangement portion of the base body. With this aspect, a rotor exhibiting the functional effects of the first to eighth aspects can be obtained.

[0018] According to a tenth aspect, a bicycle hub dynamo is provided, which comprises the hub shell according to the ninth aspect and further comprises a hub axle rotatably disposed in the main body of the hub shell, and a stator fixed to the hub axle. With this aspect, a bicycle hub dynamo can be obtained which exhibits the functional effects of the first to sixth aspects.

[0019] With the present invention, the magnet arrangement portion of the hub shell includes a flat portion and a non-flat portion. As a result, a magnet can be easily and securely positioned relative to the non-flat portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] With reference to the accompanying drawings, which form a part of this original disclosure: is Fig. 1 is a semi-cross-sectional view of a bicycle hub dynamo equipped with the hub shell according to a first embodiment; is Fig. 2 a cross-sectional view of the hub shell of the Fig. 1 illustrated bicycle hub dynamos; is Fig. 3 a cross-sectional view corresponding Fig. 2 of a hub shell according to a variant of the first embodiment; is Fig. 4 a cross-sectional view corresponding Fig. 2 of a hub shell according to a second embodiment; is Fig. 5 a cross-sectional view corresponding Fig. 2 of a hub shell according to a variant of the second embodiment; is Fig. 6 a cross-sectional view corresponding Fig. 2 of a hub shell according to a third embodiment and is Fig. 7 is a cross-sectional view of the hub shell according to a fourth embodiment and corresponds Fig. 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Selected embodiments will now be explained with reference to the drawings. Those skilled in the art will appreciate from this disclosure that the following descriptions of the embodiments are for illustrative purposes only and are not intended to limit the invention as defined by the appended claims and their equivalents.

[0022] First, with reference to Fig. 1 illustrates a bicycle hub dynamo (hub dynamo) 10 according to a first embodiment. As in Fig. As shown in Figure 1, the bicycle hub dynamo (hub dynamo) 10 is mounted on the front fork 102 of a bicycle. The hub dynamo 10 basically includes a hub axle 11, a stator 13, a rotor 15, and a hub shell 17. The stator 13 is attached to the hub axle 11. The rotor 15 is arranged radially outward from the stator 13. The hub shell 17 is attached to the rotor 15.

[0023] The hub axle 11 is hollow and is detachably attached to the front wheel fork 102, for example, by a quick-release mechanism 12. A first external threaded portion 11a is formed on the outer peripheral surface of a first end (left end in Fig. 1) of the hub axle 11. A second external thread portion 11b is formed on the outer peripheral surface of a second end (right end in Fig. 2) of the hub shaft 11. Furthermore, an axial groove 11c extending in the axial direction from a central portion to the second end is formed in the outer peripheral surface of the hub shaft 11. The axial groove 11c is used for arranging a wire 22a extending from a coil 22 (explained later). A connector 29 for conducting electrical power from the coil 22 to a headlight or other external device is attached to the second external threaded portion 11b with a nut member 50.

[0024] The rotor 15 has a coil former 20 through which the hub axle 11 passes, a coil 22 wound on the coil former 20, and a yoke 25 arranged on the coil former 20 so as to surround the periphery of the coil 22. The rotor 15 is non-rotatably attached to the hub axle 11 by two fastening elements 27, which are attached to the hub axle 11 at both ends of the coil former 20.

[0025] The rotor 15 includes the hub shell 17 and a ring magnet 28 fixed to the inner peripheral surface of the hub shell 17. The magnet 28 has N poles and S poles arranged alternately along the circumferential direction Y. The magnet 28 is a bonded magnet fixed to the inner peripheral surface of the hub shell 17 by injection molding. The bonded magnet is made of a mixture of ferrite, a rare earth alloy, or other magnetic powder and a synthetic resin (including an adhesive). Likewise, there are no particular restrictions on the type of magnetic powder, and any magnetic powder that provides the required performance can be selected. Similarly, there are no particular restrictions on the synthetic resin. The hub shell 17 is supported at both ends by a first bearing 30 and a second bearing 32, allowing it to rotate freely around the hub shaft 11. The hub shell 17 includes a shell body 40, a magnet arranging portion 42, and a cover member 44. The shell body 40 is generally cylindrical and open at one end. The magnet arranging portion 42 is located on the inner peripheral surface 40a of the shell body 40. The shell body 40 is an example of a base body. As shown in Fig. 1, the housing body 40 is tubular and does not have a perfect cylindrical shape with a constant circular cross-section. Furthermore, the housing body 40 need not have a circular cross-section at all. For example, the housing body 40 may be a tubular member with a square cross-section, an octagonal cross-section, etc. Therefore, the term "cylindrical shape" as used herein is not limited to a tubular member with a circular cross-section.

[0026] The magnet 28 is injection-molded onto the inner peripheral surface 40a of the housing body 40. The cover member 44 covers the opening 40b of the housing base body 40. The housing base body 40 has two annular hub flanges 40c. The annular hub flanges 40c are formed on the outer peripheral surface of the housing base body 40 such that one of the hub flanges 42 is arranged at each end of the housing base body 40. An internally threaded portion 40d is located on the inner peripheral surface 40a of the opening 40b of the housing base body 40. The internally threaded portion 40d engages the cover member 44 such that the cover member 44 is screwed into the opening 40b of the housing base body 40. A first end portion of the housing base body 40 is rotatably mounted on the hub axle 11 by the first bearing 30. The first end portion of the housing base body 40 is located on the opposite side of the opening 40b.

[0027] As in Fig. 2, the magnet assembly portion 42 includes a planar portion 42a and a non-planar portion 42b relative to the planar portion 42a. As used herein, the term "planar" means regular; free of any noticeable protrusions or dents. The non-planar portion 42b is configured as a recess (in this example, a narrow helical groove) relative to the planar portion 42a. The planar portion 42a includes a circular cylindrical surface that extends helically. The non-planar portion 42b includes a groove (narrow groove) that extends helically and linearly. As a result, the helical and linear non-planar portion 42b extends to be non-parallel to both the axial direction X and the circumferential direction Y of the housing body 40.Since a part of the magnet 28 enters the non-planar portion 42b when the magnet 28 is injection molded, the movement of the magnet 28 in the axial direction X and the circumferential direction Y can be restricted, and the magnet 28 can be positioned easily and securely.

[0028] Returning to Fig. 1, the cover element 44 is attached to the housing base body 40 by screwing it together with the internally threaded portion 40d of the housing base body 40. The cover element 44 has a cylindrical portion 44a that engages the internally threaded portion 40d. The cover element 44 is rotatably mounted on the hub axle 11 by the second bearing 32 attached to the cover element 44.

[0029] With the hub shell 17 configured as described above, at least the magnet arranging portion 42 of the housing main body 40 is disposed within a magnet molding die. A molten synthetic resin with magnetic powder mixed therein is injected into the die, and the magnet 28 is formed. Thereafter, a portion of the molten material enters the helical and recessed non-planar portion 42b. As a result, the movement of the magnet 28 in the axial direction X and the circumferential direction Y can be restricted, and the magnet 28 is positioned easily and securely.

[0030] Also, the linear and helical non-planar portion 42b can be easily obtained because it can be formed by continuous processing.

[0031] Now, with reference to Fig. 3 discusses a variant of the first embodiment. In this variant of the first embodiment, a hub shell 117 replaces the hub shell 17 in the bicycle hub dynamo 10 of the first embodiment. The hub shell 117 includes a shell body 140 and a magnet locating portion 142. Essentially, as discussed below, the magnet locating portion 142 of this variant is the only difference from the first embodiment. Therefore, the constituent features of the magnet locating portion 142 of this variant will be explained, while explanations of other parts of the hub shell 117 will be omitted for brevity.

[0032] As in Fig. 3, in this variant of the first embodiment, the magnet arrangement portion 142 of the housing base body 140 of the hub shell 117 includes a planar portion 142a and a non-planar portion 142b relative to the planar portion 142a. The planar portion 142a of the magnet arrangement portion 142 includes a circular cylindrical surface that is helically shaped. The non-planar portion 142b also includes a circular cylindrical surface that is helically shaped. The inner diameter of the non-planar portion 142b is larger than the inner diameter of the planar portion 142a. In this variant of the first embodiment, the axial lengths of the planar portion 142a and the non-planar portion 142b are substantially the same. However, the axial lengths of the planar portion 142a and the non-planar portion 142b may also be different from one another.In order for this variant to allow the larger part of the magnet 28 to enter the non-planar portion 142b, in addition to the previously explained effects of the first embodiment, the magnetic force of the magnet can also be increased.

[0033] Now, with reference to Fig. 4 discusses a hub shell 217 according to a second embodiment. In this second embodiment, the hub shell 217 replaces the hub shell 17 in the bicycle hub dynamo 10 of the first embodiment. The hub shell 217 includes a shell body 240 and a magnet locating portion 242. Basically, as discussed below, the magnet locating portion 242 of this second embodiment is the only difference from the first embodiment. Therefore, the constituent features of the magnet locating portion 242 of this second embodiment will be explained, while explanations of other parts of the hub shell 217 will be omitted for brevity.

[0034] As in Fig. As shown in Figure 4, the magnet arrangement portion 242 of the housing base 240 of the hub shell 217 includes a planar portion 242a and a non-planar portion 242b relative to the planar portion 242a. The non-planar portion 242b includes a plurality of elliptical grooves inclined at an angle. The planar portion 242a includes a plurality of circular cylindrical surfaces formed between the grooves of the non-planar portion 242b. Each of the elliptical grooves of the non-planar portion 242b has an endless shape. Therefore, in the second embodiment, the non-planar portion 242b is non-parallel with respect to both the axial direction X and the circumferential direction Y. With this embodiment, since each of the elliptical grooves of the non-planar portion 242b has an endless shape and can be formed by a single process, the non-planar portion 242b can be easily obtained.Although the non-planar portion 242b of the second embodiment is illustrated with six endless grooves, any number of grooves is conceivable as long as at least one groove is present.

[0035] Now, with reference to Fig. 5 discusses a hub shell 317 according to a variant of the second embodiment. In this variant of the second embodiment, the hub shell 317 replaces the hub shell 17 in the bicycle hub dynamo 10 of the first embodiment. The hub shell 317 includes a shell body 340 and a magnet arranging portion 342. Basically, as explained below, the magnet arranging portion 342 of this variant of the second embodiment is the only difference from the first embodiment. Therefore, the constituent features of the magnet arranging portion 342 of this variant of the second embodiment will be explained, while explanations of other parts of the hub shell 317 will be omitted for brevity.

[0036] As in Fig. As shown in Figure 5, the magnet arrangement portion 342 of the housing main body 340 of the hub shell 317 includes a planar portion 342a and a plurality of endless non-planar portions 342b and 342c relative to the planar portion 342a. The endless non-planar portions 342b and 342c have different inclination directions provided in the magnet arrangement portion 342 of the hub main body 340. Therefore, the axial length of the circular cylindrical surface of the planar portion 342a varies stepwise depending on the position along the circumferential direction. The non-planar portions 342b and 342c are alternately arranged to be left-right mirror images of each other in a sectional view. Even with this configuration, the magnet can be positioned easily and securely. A plurality of the non-planar portions 342b and a plurality of the non-planar portions 342c may also be arranged side by side in the magnet arrangement portion 342.

[0037] Now, with regard to Fig. 6, a hub shell 417 according to a third embodiment is discussed. In this third embodiment, the hub shell 417 replaces the hub shell 17 in the bicycle hub dynamo 10 of the first embodiment. The hub shell 417 includes a shell body 440 and a magnet arranging portion 442. Basically, as explained below, the magnet arranging portion 442 of this third embodiment is the only difference from the first embodiment. Therefore, the constituent features of the magnet arranging portion 442 of this third embodiment will be explained, while explanations of other parts of the hub shell 417 will be omitted for brevity.

[0038] As in Fig. 6, the magnet arrangement portion 442 of the housing main body 440 of the hub shell 417 includes a planar portion 442a and a plurality of non-planar portions 442b and 442c that are endless relative to the planar portion 442a. The first non-planar portions 442b are recessed and linear and extend in the circumferential direction Y. The second non-planar portions 442b are recessed and linear and extend in the axial direction X. The planar portion 442a includes a surface disposed between the first non-planar portion 442b and the second non-planar portion 442c. Fig. 6 shows only one of the second non-planar portions 442c, but preferably, another of the second non-planar portions 442c is arranged 180 degrees from the illustrated second non-planar portion 442c. With the third embodiment, the first non-planar portions 442b and the second non-planar portions 442c can be easily formed because they have simple shapes.

[0039] Now, with regard to Fig. 7 discusses a hub shell 217 according to a fourth embodiment. In this fourth embodiment, the hub shell 517 replaces the hub shell 17 in the bicycle hub dynamo 10 of the first embodiment. The hub shell 517 includes a shell body 540 and a magnet arranging portion 542. Basically, as explained below, the magnet arranging portion 542 of this fourth embodiment is the only difference from the first embodiment. Therefore, the constituent features of the magnet arranging portion 542 of this fourth embodiment will be explained, while explanations of other parts of the hub shell 517 will be omitted for brevity.

[0040] As in Fig.As shown in Fig. 7, the magnet arrangement portion 542 of the housing main body 540 of the hub shell 517 includes a planar portion 542a and a non-planar portion 542b relative to the planar portion 542a. The non-planar portion 542b has a linear protrusion. The non-planar portion 542b extends helically similarly to the non-planar portion 542b of the first embodiment. Other than the non-planar portion 542b having a protruding shape, the hub shell 517 of the fourth embodiment is the same as the hub shell 17 of the first embodiment, and therefore, a detailed explanation of the hub shell 517 is omitted. It is also clearly conceivable that the non-planar portions of the second and third embodiments may be configured as protrusions.

[0041] The present invention is not limited to the embodiments described above. Numerous modifications may be made without departing from the scope of the invention as set forth in the claims.

[0042] Although the magnet arranging portion 42 is provided on the housing main body 40 in the above-described embodiments, the present invention is not limited to such a configuration. For example, the magnet arranging portion may be provided on the inner peripheral surface of the cover member. In such a case, the cover member is an example of the main body.

[0043] Although the bicycle hub dynamo is intended for a front wheel in the embodiments explained above, the present invention is not limited to front wheel applications. For example, the present invention can be applied to a bicycle hub dynamo for a rear wheel.

[0044] Furthermore, components shown as directly connected or contacting each other may have intermediate structures interposed between them unless otherwise noted. The functions of one element may be performed by two, and vice versa, unless otherwise noted. The structures and functions of one embodiment may be adopted in another embodiment. Not all advantages need to be present in a particular embodiment. Any feature that is unique from the prior art, alone or in combination with other features, should also be considered a separate description of applicant's further inventions, including the structural and / or functional concepts embodied by that feature(s).Thus, the foregoing descriptions of the embodiments according to the present invention are intended to be illustrative only and not limitative of the invention as defined by the appended claims and their equivalents. LIST OF REFERENCE SYMBOLS 10 hub dynamo 15 Rotor 17, 117, 217, 317, 417, 517 hub shells 28 Magnet 40, 140, 240, 340, 440, 540 hub body 42, 142, 242, 342, 442, 542 Magnet assembly section 42a, 142a, 242a, 342a, 442a, 542a flat section 42b, 142b, 242b, 342b, 442b, 542b non-planar section 442b first non-planar section 442c second non-planar section

Claims

[1] Rotor for a bicycle hub dynamo, comprising: a hub shell having a base body having a tubular shape with an inner peripheral surface, and a magnet arranging portion provided on the inner peripheral surface of the base body for arranging a magnet formed therein by injection molding, wherein the magnet arranging portion is provided in an axial center portion of the inner peripheral surface of the base body such that the magnet arranging portion opposes a coil arranged radially inside the magnet arranging portion when the rotor is installed in the bicycle hub dynamo; and a magnet formed by injection molding in the magnet arranging portion of the hub shell; wherein the magnet is a bonded magnet made of a mixture of magnetic powder and a synthetic resin; wherein the magnet arrangement portion comprises a planar portion and a non-planar portion, wherein the non-planar portion is configured as one of a recess and a projection relative to the planar portion, wherein the non-planar portion has a linear shape and extends non-parallel with respect to each of the axial direction and the circumferential direction of the base body, and wherein a part of the magnet enters the non-planar portion when the magnet is injection-molded. [2] The rotor of claim 1, wherein the non-planar portion is configured as a recess. [3] The rotor of claim 1, wherein the non-planar portion is configured as a protrusion. [4] Rotor for a bicycle hub dynamo, comprising: a hub shell having a base body having a tubular shape with an inner peripheral surface, the inner peripheral surface of the base body having a magnet arranging portion, the magnet arranging portion including a non-planar portion in the form of a linear recess formed in the inner peripheral surface; and a magnet injection-molded onto the magnet arranging portion on the inner peripheral surface of the base body so as to enter the groove; wherein the magnet is a bonded magnet made of a mixture of magnetic powder and a synthetic resin, and wherein the magnet at the magnet arrangement portion forms a radially innermost surface of the rotor. [5] A rotor according to any one of claims 1 to 4, wherein the non-planar portion has a helical shape. [6] A rotor according to any one of claims 1 to 4, wherein the non-planar portion has an endless shape. [7] The rotor of claim 6, wherein the non-planar portion comprises a plurality of separate non-planar portions. [8] The rotor according to claim 4, wherein the non-planar portion comprises a first non-planar portion having a linear shape and extending in the axial direction of the base body, and a second non-planar portion having a linear shape and extending in the circumferential direction of the base body. [9] Bicycle hub dynamo equipped with a rotor according to one of claims 1 to 8.

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