BICYCLE BOTTOM BRACKET SET

Abstract

Bicycle bottom bracket set (10), comprising: a first bearing set (22a) and a first support bearing component (24a) having a first suspension attachment portion (32a) with a first outer surface (44a) configured to be inserted into a first opening end (12a) of a suspension part (12) of a bicycle frame, and a first bearing attachment portion (34a) with a first inner surface (46a) configured to that the first bearing set (22a) is inserted therein, wherein the first inner surface (46a) has a first bearing passage surface (48a) through which the first bearing set (22a) can pass in the pressed-in state, and a first bearing fixing surface (50a) which is positioned axially inwardly with respect to the first bearing passage surface (48a) and is configured such that the first bearing set (22a) is fixed thereto, wherein the axially inner end refers to an end closer to the central position of the suspension part (12) of the bicycle frame in the axial direction, an inner diameter (R1) of the first bearing passage surface (48a) is smaller than an inner diameter (R2) of the first bearing fixing surface (50a), the first inner surface (46a) has a first uneven surface (52a) formed between the first bearing passage surface (48a) and the first bearing fixing surface (50a), and the first uneven surface (52a) is an inclined surface (56a).

Description

[0001] The present invention relates to a bicycle bottom bracket assembly attached to a suspension part of a bicycle frame.

[0002] A tubular bicycle bottom bracket assembly is mounted on a suspension part of a bicycle frame. The bottom bracket assembly includes a crankshaft, and the bicycle's crank arms are attached to both ends of the crankshaft. The crankshaft is rotatably supported relative to the bicycle frame. European Patent Laid-Open Publication No. 1780111 discloses such a bicycle bottom bracket assembly, in which a bearing assembly including an inner ring, an outer ring, and a rolling element is mounted from the axially outer end. A conventional bottom bracket assembly includes a bearing assembly and a support bearing member having a suspension attachment portion formed on the outer surface and a bearing fixing surface formed on the inner surface. The bearing assembly is held by being press-fitted to the bearing fixing surface.

[0003] In such a conventional bottom bracket assembly, the bearing set is held in place by an interference fit. This compresses the outer race of the bearing set, forcing it tightly against the rolling element. This likely increases the rotational resistance of the bearing set and makes it more difficult for the crankshaft to rotate.

[0004] An object of this invention is to provide a bicycle bottom bracket assembly in which a bearing set is mounted from the axially outer end, and the rotational resistance of the bearing set can be reduced while securely holding the bearing set.

[0005] This objective is achieved with a bicycle bottom bracket assembly according to claim 1.

[0006] The bicycle bottom bracket assembly according to claim 1 of this invention comprises a first bearing set and a first support bearing member. The first support bearing member includes a first suspension attachment portion having a first outer surface configured to be inserted into a first opening end of a suspension member of a bicycle frame, and a first bearing attachment portion having a first inner surface configured to have the first bearing set inserted therein. The first inner surface includes a first bearing passage surface through which the first bearing set can pass when pressed in, and a first bearing fixing surface positioned axially inwardly of the first bearing passage surface and configured to fix the first bearing set thereto. The inner diameter of the first bearing passage surface is smaller than the inner diameter of the first bearing fixing surface.The first inner surface has a first uneven surface formed between the first bearing passage surface and the first bearing fixing surface. Thus, the first bearing set can be effectively held by the first uneven surface. The first uneven surface is an inclined surface. Thus, the first bearing set can be easily mounted from the first bearing passage surface to the first bearing fixing surface.

[0007] When the bottom bracket assembly is attached to the bicycle, the first outer surface of the first suspension attachment portion of the first support bearing member is inserted into the first opening end of the suspension member of the bicycle frame, and the first support bearing member is fixed to the suspension member. The first bearing assembly is mounted on the inner peripheral surface of the first support bearing member.

[0008] When assembling the bottom bracket assembly, the first bearing set is inserted from the axially outer end of the first support bearing member. The "axially outer end" refers to an end farther away from the central position of the suspension part of the bicycle frame in the axial direction. The "axially inner end" refers to an end closer to the central position of the suspension part of the bicycle frame in the axial direction. The first bearing set passes through the first bearing passage surface with a small inner diameter in the press-fitted state, and the first bearing set is fixed to the first bearing fixing surface with a large inner diameter. With this configuration, the pressure exerted on the first bearing set when fixed to the first bearing fixing surface can be reduced compared to the pressure exerted on the first bearing set when passing through the first bearing passage surface.After the first bearing set is fixed to the first bearing fixing surface by an appropriate fixing method such as press-fitting or bonding, the first bearing set is held by the first bearing through surface with a small inner diameter. This allows the rotational resistance of the first bearing set to be reduced while holding the first bearing set.

[0009] Regarding the bicycle bottom bracket assembly according to a second aspect of this invention, the bicycle bottom bracket assembly is further configured such that the first outer surface and the first inner surface overlap at least partially in the radial direction. Consequently, since the inner diameter of the first bearing fixing surface can be sufficiently large in a bicycle bottom bracket assembly mounted and fixed to a suspension part of the bicycle frame, for example, by press-fitting, the pressure exerted on the first bearing set can be prevented from increasing sharply when the bicycle bottom bracket assembly is mounted to the suspension part of the bicycle frame. Thus, the rotational resistance of the first bearing set can be reduced while supporting the first bearing set.

[0010] Regarding the bicycle bottom bracket assembly according to a third aspect of this invention, the bicycle bottom bracket assembly is configured such that the first outer surface is disposed axially inward relative to the first inner surface. Since the first outer surface and the first inner surface do not overlap in the axial direction, pressure is not easily applied to the first inner surface when the first outer surface is fixed to the suspension member. Thus, the rotational resistance of the first bearing set can be effectively reduced while supporting the first bearing set.

[0011] Regarding the bicycle bottom bracket assembly according to a fourth aspect of this invention, the bicycle bottom bracket assembly is configured such that the first outer surface is press-fitted into the first opening end of the suspension part of the bicycle frame. Consequently, since the inner diameter of the first bearing fixing surface can be set sufficiently large, the pressure applied to the first bearing set can be prevented from increasing sharply even when pressure is applied to the first support bearing member by press-fitting. Thus, the rotational resistance of the first bearing set can be reduced while the first bearing set is held.

[0012] Regarding the bicycle bottom bracket assembly according to a fifth aspect of this invention, the bicycle bottom bracket assembly is configured such that the first outer surface is screwed into the first opening end of the suspension part of the bicycle frame. Since no excessive pressure is applied to the first support bearing component, the rotational resistance of the first bearing set can be reduced while supporting the first bearing set.

[0013] Regarding the bicycle bottom bracket assembly according to a sixth aspect of this invention, the bicycle bottom bracket assembly is configured such that the first bearing passage surface is formed around the entire circumference in the circumferential direction of the first inner surface. Thus, a sealing member and the like can be easily arranged in the first bearing passage surface.

[0014] Regarding the bicycle bottom bracket assembly according to a seventh aspect of this invention, the bicycle bottom bracket assembly is configured such that the first bearing passage surface is formed with a plurality of sections spaced apart from each other at intervals in the circumferential direction of the first inner surface. Thus, the first bearing assembly can be easily mounted to the first bearing fixing surface from the first bearing passage surface.

[0015] Regarding the bicycle bottom bracket assembly according to an eighth aspect of this invention, the bicycle bottom bracket assembly is configured such that the inclination angle of the inclined surface relative to the first bearing fixing surface is 10° or more. Since the angle of the inclined surface is sufficiently large, the first bearing assembly can be securely held.

[0016] Regarding the bicycle bottom bracket assembly according to an alternative aspect, the bicycle bottom bracket assembly is configured such that the first uneven surface is an abutment surface extending in the radial direction. Thus, since the first uneven surface has a step perpendicular to the crankshaft, a side surface of the first bearing set can be retained at the axially outer end by contacting the first uneven surface after passing through the first bearing passage surface.

[0017] Regarding the bicycle bottom bracket assembly according to a ninth aspect of this invention, the bicycle bottom bracket assembly is configured such that the difference between the inner diameter of the first bearing passage surface and the inner diameter of the first bearing fixing surface is 0.2 mm or less.

[0018] Regarding the bicycle bottom bracket assembly according to a tenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the difference between the inner diameter of the first bearing passage surface and the inner diameter of the first bearing fixing surface is 0.1 mm or less.

[0019] Regarding the bicycle bottom bracket assembly according to an eleventh aspect of this invention, the bicycle bottom bracket assembly is configured to fix the first bearing set to the first bearing fixing surface by press-fitting. Since the first bearing set can be fixed to the first bearing fixing surface without using an adhesive and the like, the assembly process of the bicycle bottom bracket assembly can be simplified.

[0020] Regarding the bicycle bottom bracket assembly according to a twelfth aspect of this invention, the bicycle bottom bracket assembly is configured such that the first bearing set is fixed to the first bearing fixing surface by adhesive bonding. Since the first bearing set is fixed by adhesive bonding, the first bearing set can be fixed to the first bearing fixing surface by a clearance fit. Thus, almost no pressure is exerted on the first bearing set, and the rotational resistance of the first bearing set can be reduced while the first bearing set is held.

[0021] Regarding the bicycle bottom bracket assembly according to a thirteenth aspect of this invention, the bicycle bottom bracket assembly is configured such that an adhesive holding portion is formed on the first bearing fixing surface. Thus, excess adhesive generated on the first bearing fixing surface during assembly of the first bearing assembly can be moved toward the adhesive holding portion.

[0022] Related to the bicycle bottom bracket assembly according to a fourteenth aspect of this invention, the bicycle bottom bracket assembly further comprises a second bearing set and a second support bearing member. The second support bearing member includes a second suspension attachment portion having a second outer surface configured to be inserted into a second opening end of the suspension part of the bicycle frame, and a second bearing attachment portion having a second inner surface configured to receive the second bearing set therein. The second inner surface includes a second bearing passage surface through which the second bearing set can pass when pressed in, and a second bearing fixing surface positioned axially inwardly of the second bearing passage surface and configured to fix the second bearing set thereto.The inner diameter of the second bearing passage surface is smaller than the inner diameter of the second bearing fixing surface.

[0023] When attaching the bottom bracket assembly to a bicycle, the first support bearing member is fixed to the suspension member through the first opening end, and the second support bearing member is fixed to the suspension member through the second opening end. Thus, both ends of the crankshaft can be supported. Furthermore, similar effects to those in the above-described first aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0024] With respect to the bicycle bottom bracket assembly according to a fifteenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second outer surface and the second inner surface overlap at least partially in the radial direction. Thus, similar effects to those in the above-described second aspect of this invention can be achieved with respect to the second support bearing component and the second bearing set.

[0025] Regarding the bicycle bottom bracket assembly according to a sixteenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second outer surface is positioned axially inward relative to the second inner surface. Thus, similar effects to those in the above-described third aspect of this invention can be achieved with respect to the second support bearing component and the second bearing set.

[0026] Regarding the bicycle bottom bracket assembly according to a seventeenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second outer surface is press-fitted into the second opening end of the suspension part of the bicycle frame. Thus, similar effects to those in the above-described fourth aspect of this invention can be achieved with respect to the second support bearing component and the second bearing set.

[0027] Regarding the bicycle bottom bracket assembly according to an eighteenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second outer surface is screwed into the second opening end of the suspension part of the bicycle frame. Thus, similar effects to those in the above-described fifth aspect of this invention can be achieved with respect to the second support bearing component and the second bearing set.

[0028] Regarding the bicycle bottom bracket assembly according to a nineteenth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second inner surface has a second uneven surface formed between the second bearing passage surface and the second bearing fixing surface. Thus, similar effects to those in the above-described sixth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0029] Regarding the bicycle bottom bracket assembly according to a twentieth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second bearing passage surface is formed around the entire circumference in the circumferential direction of the second inner surface. Thus, similar effects to those in the above-described seventh aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0030] Regarding the bicycle bottom bracket assembly according to a twenty-first aspect of this invention, the bicycle bottom bracket assembly is configured such that the second bearing passage surface is formed with a plurality of sections spaced apart from each other at intervals in the circumferential direction of the second inner surface. Thus, similar effects to those in the above-described eighth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0031] Regarding the bicycle bottom bracket assembly according to a twenty-second aspect of this invention, the bicycle bottom bracket assembly is configured such that the second uneven surface is an inclined surface. Thus, similar effects to those in the above-described ninth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0032] Regarding the bicycle bottom bracket assembly according to a twenty-third aspect of this invention, the bicycle bottom bracket assembly is configured such that the inclination angle of the inclined surface relative to the second bearing fixing surface is 10° or more. Thus, since the angle of the inclined surface is sufficiently large, similar to the effects of the tenth aspect of this invention described above, the second bearing assembly can be securely held.

[0033] Regarding the bicycle bottom bracket assembly according to a twenty-fourth aspect of this invention, the bicycle bottom bracket assembly is configured such that the difference between the inner diameter of the second bearing passage surface and the inner diameter of the second bearing fixing surface is 0.2 mm or less.

[0034] Regarding the bicycle bottom bracket assembly according to a twenty-fifth aspect of this invention, the bicycle bottom bracket assembly is configured such that the difference between the inner diameter of the second bearing passage surface and the inner diameter of the second bearing fixing surface is 0.1 mm or less.

[0035] Regarding the bicycle bottom bracket assembly according to a twenty-sixth aspect of this invention, the bicycle bottom bracket assembly is configured such that the second bearing set is press-fitted to the second bearing fixing surface. Thus, similar effects to those in the above-described fourteenth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0036] Regarding the bicycle bottom bracket assembly according to a twenty-seventh aspect of this invention, the bicycle bottom bracket assembly is configured such that the second bearing set is fixed to the second bearing fixing surface by adhesive bonding. Thus, similar effects to those of the above-described twelfth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0037] Regarding the bicycle bottom bracket assembly according to a twenty-eighth aspect of this invention, the bicycle bottom bracket assembly is configured such that an adhesive holding portion is formed on the second bearing fixing surface. Thus, similar effects to those in the above-described thirteenth aspect of this invention can be achieved with respect to the second support bearing member and the second bearing set.

[0038] Related to the bicycle bottom bracket assembly according to a twenty-ninth aspect of this invention, the bicycle bottom bracket assembly further includes a tubular member that prevents the ingress of foreign substances. The first support bearing member further includes a first tubular member attachment portion configured to attach a first end of the tubular member thereto. The second support bearing member further includes a second tubular member attachment portion configured to attach a second end of the tubular member thereto. Thus, due to the tubular member, foreign substances such as liquids or dust will not easily enter the first bearing set and the second bearing set from the inside of the suspension member.

[0039] A support bearing component of a bicycle bottom bracket assembly according to a twenty-ninth aspect of this invention is configured to be attached to the suspension part of the bicycle frame. The support bearing component includes a suspension attachment portion and a bearing attachment portion. The suspension attachment portion has an outer surface configured to be inserted into an opening end of the suspension part of the bicycle frame. The bearing attachment portion has an inner surface configured to receive a bearing set of the bicycle bottom bracket assembly. The inner surface includes a bearing passage surface through which the bearing set can pass when pressed in, and a bearing fixing surface positioned axially inwardly of the bearing passage surface and configured to fix the bearing set thereto.The inner diameter of the bearing passage surface is smaller than the inner diameter of the bearing fixing surface. Thus, similar effects to those in the first aspect of this invention described above can be achieved.

[0040] Accordingly, with this invention, since the inner diameter of the bearing fixing surface is larger than the inner diameter of the bearing passage surface, the pressure exerted on the bearing set fixed to the bearing fixing surface can be reduced compared to the pressure exerted on the bearing set when it passes through the bearing passage surface. Likewise, the bearing set can be held by the bearing passage surface with a small inner diameter. Thus, the rotational resistance of the bearing set can be reduced while the bearing set is held.

[0041] In another aspect of this invention, since the holding structure is formed between the bearing fixing surface and the bearing passage surface, the rotational resistance of the bearing set can be reduced while holding the bearing set. Fig. 1 is a cross-sectional view showing the assembled state of a bicycle bottom bracket assembly according to a first embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of a first bottom bracket assembly according to the first embodiment of the present invention. Fig. 3 is a cross-sectional view of section A of Fig. 2. Fig. 4 is a Fig. 2 corresponding view according to an alternative embodiment not according to the invention. Fig. 5 is an enlarged cross-sectional view of section B of the non-inventive embodiment of the Fig. 4. Fig. 6 is a Fig. 2 corresponding view according to another embodiment of the present invention. Fig. 7 is a Fig. 2 corresponding view according to an alternative embodiment not according to the invention.

[0042] In Fig. 1, a bicycle bottom bracket assembly 10 according to a first embodiment of the present invention is provided in a tubular suspension member 12 of a bicycle frame for supporting both ends of a crankshaft 60 of a bicycle. The crankshaft 60 is a hollow axle. A first crank arm 62a is provided at a first end (in Fig. 1 at the left end) of the crankshaft 60, and a second crank arm 62b is mounted at a second end (in Fig. 1 at the right end) of the crankshaft 60. The second crank arm 62b has a plurality of sprockets 64. The bicycle bottom bracket assembly 10 comprises a first bottom bracket assembly 10a, a second bottom bracket assembly 10b, and a tubular member 20 intended to prevent the entry of foreign substances. The first bottom bracket assembly 10a is mounted on a first opening end 12a of the suspension part 12 of the bicycle on the left side in Fig. 1. The second bottom bracket assembly 10b is mounted on a second opening end 12b of the suspension part 12 of the bicycle on the right side in Fig. 1. The tubular member 20 is arranged between the first bottom bracket assembly 10a and the second bottom bracket assembly 10b. The first bottom bracket assembly 10a and the second bottom bracket assembly 10b are arranged to be substantially line-symmetrical with respect to the central position C1 of the suspension member 12 in the axial direction. The cross-sectional shape of the first bottom bracket assembly 10a and the cross-sectional shape of the second bottom bracket assembly 10b are generally circular and centered around an axis C2 of the crankshaft 60.

[0043] The first bottom bracket assembly 10a mainly comprises a first bearing set 22a and a first support bearing component 24a. The second bottom bracket assembly 10b mainly comprises a second bearing set 22b and a second support bearing component 24b. The first bottom bracket assembly 10a and the second bottom bracket assembly 10b have substantially the same configuration. In the following explanation, therefore, the first bottom bracket assembly 10a will be referred to with respect to Fig. 2, and a summary of the configuration of the second bottom bracket assembly 10b is related to Fig. 1 explained.

[0044] As in Fig. 2, the first bearing set 22a is a rolling bearing including a first outer ring 26a, a first inner ring 28a, and a first rolling element 30a disposed between the first outer ring 26a and the first inner ring 28a. In this embodiment, the axial length of the first inner ring 28a is greater than the axial length of the first outer ring 26a, so that the first inner ring 28a extends axially outward relative to the first outer ring 26a. Here, the "axially outer end" refers to an end farther away from the central position C1 of the suspension member 12 along the axis C2 of the crankshaft 60. The "axially inner end" refers to an end closer to the central position C1 of the suspension member 12 along the axis C2 of the crankshaft 60. A first cover member 40a is disposed between the first inner ring 28a and the first crank arm 62a. The first cover member 40a contacts the first crank arm 62a.The first cover member 40a is disposed between the first crank arm 62a and the first inner ring 28a, and also extends between the first inner ring 28a and an outer peripheral surface of the crankshaft 60. A first sealing member 42a is mounted between a side surface of the outer ring 26a at the axially outer end and an outer peripheral surface of the first inner ring 28a. The first sealing member 42a is mounted on a first bearing passage surface 48a, described below. This prevents foreign substances from entering the first bearing set 22a from the axially outer end toward the axially inner end.

[0045] The first support bearing member 24a is a tubular shoulder member. The first support bearing member 24a includes a first suspension attachment portion 32a, a first bearing attachment portion 34a, a first boss portion 36a, and a first tubular member attachment portion 38a. The first suspension attachment portion 32a includes a first outer surface 44a configured to be inserted into the first opening end 12a of the suspension member 12. In the first embodiment, the first outer surface 44a is inserted into the first opening end 12a of the suspension member 12 in a press-fitted state. More specifically, the first outer surface 44a is secured to the first opening end 12a by precise fitting.

[0046] The first bearing mounting portion 34a has a first inner surface 46a configured to receive the first bearing set 22a. The first inner surface 46a is configured to at least partially radially overlie the first outer surface 44a. The first inner surface 46a has a first bearing passage surface 48a through which the first bearing set 22a can pass when pressed in, and a first bearing fixing surface 50a positioned axially inwardly with respect to the first bearing passage surface 48a and configured to fix the first bearing set 22a thereto. The inner diameter of the first bearing passage surface 48a is smaller than the inner diameter of the first bearing fixing surface 50a. More specifically, as shown in Fig. 3 where section A of Fig. 2, an inner diameter difference D1 between the inner diameter R1 of the first bearing passage surface 48a and the inner diameter R2 of the first bearing fixing surface 50a is set to 0.2 mm or less, and preferably to 0.1 mm or less, so that the first bearing set 22a can pass through the first bearing passage surface 48a with corresponding ease. The first bearing set 22a is press-fitted into the first bearing fixing surface 50a and fixed thereto. Preferably, the inner diameter R2 of the first bearing fixing surface 50a is set so that the first outer ring 26a of the first bearing set 22a is press-fitted accordingly tightly.

[0047] The first inner surface 46a further includes a first uneven surface 52a formed between the first bearing passage surface 48a and the first bearing fixing surface 50a, and a position determining wall portion 54a that determines the axial position of the press-fitted first bearing set 22a. The first uneven surface 52a has a first inclined surface 56a. Preferably, the inclination angle of the first inclined surface 56a relative to the first bearing fixing surface 50a is 10° or more, so that the first bearing set 22a, mounted on the first bearing fixing surface 50a, can be securely held.

[0048] As in Fig. 2, the first boss portion 36a is arranged to contact the end surface of the suspension member 12 on the first opening end 12a side. This determines the axial position of the first support bearing member 24a. The first tubular member fixing portion 38a is tubular, and its diameter is smaller than that of the first outer surface 44a. The outer peripheral surface of the first end of the tubular member 20 is connected to the inner peripheral surface of the first tubular member fixing portion 38a. An O-ring 58 is arranged between the inner peripheral surface of the first tubular member fixing portion 38a and the outer peripheral surface of the first end of the tubular member 20. The O-ring 58 prevents foreign substances from entering the first bearing set 22a through the inside of the suspension member 12.

[0049] As in Fig. 1, the first end of the tubular member 20 is attached to the first tubular member attachment portion 38a of the first support bearing member 24a, and a second end of the tubular member 20 is attached to a second tubular member attachment portion 38b of the second support bearing member 24b.

[0050] As in Fig. 1, the second bottom bracket assembly 10b has similar elements to the elements of the first bottom bracket assembly 10a. Reference symbol "b" is assigned to the elements of the second bottom bracket assembly 10b, while reference symbol "a" is assigned to the elements of the first bottom bracket assembly 10a. As shown, for example, in Fig. 1, the second bearing set 22b of the second bottom bracket assembly 10b includes a second outer ring 26b, a second inner ring 28b, and a second rolling element 30b disposed between the second outer ring 26b and the second inner ring 28b. The second support bearing member 24b includes a second suspension attachment portion 32b, a second bearing attachment portion 34b, a second boss portion 36b, and a second tubular member attachment portion 38b. Since the configurations of the second suspension attachment portion 32b, the second bearing attachment portion 34b, the second boss portion 36b, and the second tubular member attachment portion 38b are similar to those of the first support bearing member 24a, they will not be explained.

[0051] In the bicycle bottom bracket assembly 10 of the first embodiment having the above-described configuration, during assembly of the first bottom bracket assembly 10a, pressure is applied to the first outer ring 26a of the first bearing set 22a by a corresponding pressing device, and the first bearing set 22a is inserted into the first inner surface 46a of the first support bearing member 24a. In this case, the first bearing set 22a passes through the first bearing passage surface 48a in the press-fitted state with great pressure. After the first outer ring 26a of the first bearing set 22a passes through the first bearing passage surface 48a, the first outer ring 26a of the first bearing set 22a passes through the first inclined surface 56a, and the position of the first outer ring 26a of the first bearing set 22a is determined in the first bearing fixing surface 50a by the position determining wall portion 54a.In this way, the first bearing set 22a is fixed to the first bearing fixing surface 50a by press-fitting with a slight pressure. After the first bearing set 22a is fixed to the first bearing fixing surface 50a, the first uneven surface 52a serves as a holding structure, and the first bearing set 22a is held because the first bearing passage surface 48a is positioned axially outward with a smaller diameter than the first bearing fixing surface 50a.

[0052] Since the inner diameter of the first bearing fixing surface 50a is larger than the inner diameter of the first bearing passage surface 48a, the pressure exerted on the first bearing set 22a fixed to the first bearing fixing surface 50a can be reduced compared to the pressure exerted on the first bearing set 22a when it passes through the first bearing passage surface 48a. Likewise, the first bearing set 22a can be held by the first bearing passage surface 48a with a small diameter. Thus, the rotational resistance of the first bearing set 22a can be reduced while holding the first bearing set 22a. These effects can also be achieved in a similar manner in the second bottom bracket assembly 10b.

[0053] As in Fig. 4, in a first bottom bracket assembly 110a according to an alternative embodiment not according to the invention, a first support bearing component 124a is screwed into a first opening end 112a of a suspension part 112. For this purpose, the first opening end of the suspension part 112 has an internally threaded portion, and a first outer surface 144a of a first suspension attachment portion 132a of the first support bearing component 124a has an externally threaded portion. A tool engagement portion 136c for rotating the first support bearing component 124a with a tool is formed in a shoulder portion 136a.

[0054] As in Fig. 5 where section B of Fig. 4, a first uneven surface 152a of a first inner surface 146a has a first abutment surface 156a extending in the radial direction. The first abutment surface 156a is perpendicular to a first bearing passage surface 148a and a first bearing fixing surface 150a. The inner diameter difference D2 between an inner diameter R1 of the first bearing passage surface 148a and the inner diameter R2 of the first bearing fixing surface 150a is smaller than the inner diameter difference D1 of the first embodiment. This is because the first abutment surface 156a of the first uneven surface 152a, perpendicular to the first bearing fixing surface 150a, can hold the first bearing set 22a with respect to the first bearing fixing surface 150a even when the inner diameter difference D2 is small.

[0055] Furthermore, as in Fig. 4, the first bearing set 22a is bonded to the first bearing fixing surface 150a with an adhesive, instead of fixing the first bearing set 22a to the first bearing fixing surface 150a by press-fitting. Thus, the first bearing fixing surface 150a and the first outer ring 26a of the first bearing set 22a are secured to each other by a clearance fit. As shown in Fig. 4, an annular adhesive holding portion 155a is preferably formed at the edge of the orientation wall portion 54a and the first bearing fixing surface 150a. The adhesive holding portion 155a holds an adhesive that has been stripped from the first bearing set 22a during assembly.

[0056] Since the other configurations are similar to those of the first embodiment, they will not be explained and only references are made in Fig. 4 assigned.

[0057] As in Fig. 6, in a first bottom bracket assembly 210a according to another embodiment of the present invention, in a first support bearing component 224a, the position of a first suspension attachment portion 232a, which is configured to be inserted into a suspension part 212, differs from the alternative, non-inventive embodiment of the Fig. 4. In the embodiment of the Fig. 6, a first outer surface 244a of the first suspension attachment portion 232a is disposed axially inward of the first inner surface 46a of the first bearing attachment portion 34a, to which the first bearing set 22a is attached. The first outer surface 244a of the first support bearing member 224a has an externally threaded portion, and a first opening end 212a of the suspension member 212 has an internally threaded portion. The first inner surface 46a is disposed on the inner peripheral side of a large-diameter portion 236a. A tool engagement portion 236c for rotating the first support bearing member 224a with a tool is formed on the outer peripheral surface of the large-diameter portion 236a.

[0058] Since the other configurations are generally similar to those of the first embodiment, they will not be explained and only references are made in Fig. 6. Furthermore, the first outer surface 244a in the embodiment of the Fig. 6 can be fixed by pressing it into the first opening end 212a.

[0059] As in Fig. 7, in a first bottom bracket assembly 310a according to a further alternative embodiment not according to the invention, in a first support bearing component 324a, the first inner surface 346a of the first bearing mounting portion 334a, into which the first bearing set 22a is inserted, differs from the first embodiment. The first inner surface 346a has a first bearing through surface 348a, a first bearing fixing surface 350a, and a first retaining structure 352a. In this embodiment, the first bearing through surface 348a and the first bearing fixing surface 350a have the same diameter. The first bearing retaining structure 352a is formed between the first bearing through surface 348a and the first bearing fixing surface 350a. The first holding structure 352a is constructed of a first annular groove 355a and a first holding member 356a mounted on the first annular groove 355a.The first retaining member 356a is an annular member made of an elastic material, such as a C-shaped retaining ring. In this embodiment, the first bearing set 22a and the first seal member 42a are retained by the first bearing retaining structure 352a. Alternatively, only the first bearing set 22a may be retained by arranging the first bearing retaining structure 352a axially inward of the first seal member 42a.

[0060] In the embodiment of the Fig. 7, the first support structure 352a is constructed from the first support member 356a. However, the first support structure 352a may also be constructed as the uneven surface shown in the first to third embodiments. Furthermore, the first support member 356a does not need to be annular. Moreover, the first support member 356a may be made of metal or a non-metallic elastic material, such as an O-ring.

[0061] Since the other configurations are generally similar to those of the first embodiment, they will not be explained and only references are made in Fig. 7 assigned.

[0062] While the above describes embodiments of the present invention and other alternative embodiments not according to the invention, the present invention is not limited to the above-described embodiment, and various modifications are possible within a range that does not deviate from the scope of the invention. Specifically, the embodiments and modifications listed in the present description can be combined as needed. (a) In the above-described embodiments, the first bearing passage surface is formed around the entire circumference in the circumferential direction. However, the first bearing passage surface may be formed with a plurality of sections spaced apart from each other in the circumferential direction. (b) In the above-described embodiments, the first bearing set uses a rolling bearing in which the inner ring and outer ring have different lengths in the axial direction. However, a rolling bearing in which the inner ring and outer ring have the same length in the axial direction may also be used. A rolling bearing with a seal may also be used. (c) In the embodiments described above, a bottom bracket supporting the hollow crankshaft is disclosed. The present device can be adapted to a bottom bracket supporting a solid crankshaft. (d) In the above-described embodiments, the bearing assembly uses a ball bearing in which a rolling element is spherical. However, the present device is not limited to this. A rolling bearing in which the rolling element is roller-shaped or other known bearings may be used. (e) The above-described embodiments utilize the cover member disposed between the crank arm and the inner ring of the bearing set, and also between the inner ring of the bearing set and the outer peripheral surface of the crankshaft. However, this cover member may be omitted.

Claims

[1] Bicycle bottom bracket set (10), comprising: a first bearing set (22a) and a first support bearing component (24a) having a first suspension attachment portion (32a) with a first outer surface (44a) configured to be inserted into a first opening end (12a) of a suspension part (12) of a bicycle frame, and a first bearing attachment portion (34a) with a first inner surface (46a) configured to that the first bearing set (22a) is inserted therein, wherein the first inner surface (46a) has a first bearing passage surface (48a) through which the first bearing set (22a) can pass in the pressed-in state, and a first bearing fixing surface (50a) which is positioned axially inwardly with respect to the first bearing passage surface (48a) and is configured such that the first bearing set (22a) is fixed thereto, wherein the axially inner end refers to an end closer to the central position of the suspension part (12) of the bicycle frame in the axial direction, an inner diameter (R1) of the first bearing passage surface (48a) is smaller than an inner diameter (R2) of the first bearing fixing surface (50a), the first inner surface (46a) has a first uneven surface (52a) formed between the first bearing passage surface (48a) and the first bearing fixing surface (50a), and the first uneven surface (52a) is an inclined surface (56a). [2] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first outer surface (44a) and the first inner surface (46a) overlap at least partially in the radial direction. [3] Bicycle bottom bracket assembly according to claim 1, wherein the first outer surface (244a) is arranged axially inwardly relative to the first inner surface (46a). [4] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first outer surface (44a) is inserted in the press-fitted state into the first opening end (12a) of the suspension part (12) of the bicycle frame. [5] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first outer surface (144a) is screwed into the first opening end (112a) of the suspension part (112) of the bicycle frame. [6] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first bearing passage surface (48a) is arranged around the entire circumference in the circumferential direction of the first inner surface (46a). [7] The bicycle bottom bracket assembly (10) according to claim 1, wherein the first bearing passage surface (48a) is formed with a plurality of sections spaced apart from one another in the circumferential direction of the first inner surface (46a). [8] Bicycle bottom bracket assembly (10) according to claim 1, wherein the inclination angle (α) of the inclined surface (56a) relative to the first bearing fixing surface (50a) is 10° or more. [9] Bicycle bottom bracket assembly (10) according to claim 1, wherein the difference (D1) between the inner diameter (R1) of the first bearing passage surface (48a) and the inner diameter (R2) of the first bearing fixing surface (50a) is 0.2 mm or less. [10] Bicycle bottom bracket assembly (10) according to claim 1, wherein the difference (D1) between the inner diameter (R1) of the first bearing passage surface (48a) and the inner diameter (R2) of the first bearing fixing surface (50a) is 0.1 mm or less. [11] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first bearing set (22a) is fixed to the first bearing fixing surface (50a) by press-fitting. [12] Bicycle bottom bracket assembly (10) according to claim 1, wherein the first bearing set (22a) is fixed to the first bearing fixing surface (150a) by adhesive bonding. [13] The bicycle bottom bracket assembly (10) according to claim 12, wherein an adhesive holding portion (155a) is formed on the first bearing fixing surface (150a). [14] Bicycle bottom bracket set (10) according to claim 1, further comprising: a second bearing set (22b) and a second support bearing component (24b) comprising a second suspension attachment portion (32b) having a second outer surface configured to be inserted into a second opening end (12b) of the suspension part (12) of the bicycle frame, and a second bearing attachment portion (34b) having a second inner surface configured to receive the second bearing set (22b) therein, wherein the second inner surface has a second bearing passage surface through which the second bearing set (22b) can pass in the pressed-in state, and a second bearing fixing surface positioned axially inwardly relative to the second bearing passage surface and configured to fix the second bearing set (22b) thereto, and an inner diameter of the second bearing passage surface is smaller than an inner diameter of the second bearing fixing surface. [15] Bicycle bottom bracket set (10) according to claim 14, wherein the second outer surface and the second inner surface overlap at least partially in the radial direction. [16] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second outer surface is arranged axially inwardly relative to the second inner surface. [17] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second outer surface is inserted in the press-fitted state into the second opening end (12b) of the suspension part (12) of the bicycle frame. [18] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second outer surface is screwed into the second opening end of the suspension part (112) of the bicycle frame. [19] The bicycle bottom bracket assembly (10) of claim 14, wherein the second inner surface includes a second uneven surface formed between the second bearing passage surface and the second bearing fixing surface. [20] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second bearing passage surface is formed around the entire circumference in the circumferential direction of the second inner surface. [21] A bicycle bottom bracket assembly (10) according to claim 14, wherein the second bearing passage surface is formed with a plurality of sections spaced apart from one another in the circumferential direction of the second inner surface. [22] Bicycle bottom bracket assembly (10) according to claim 19, wherein the second uneven surface is an inclined surface. [23] Bicycle bottom bracket assembly (10) according to claim 22, wherein the angle of inclination of the inclined surface relative to the second bearing fixing surface is 10° or more. [24] Bicycle bottom bracket assembly (10) according to claim 14, wherein the difference between the inner diameter of the second bearing passage surface and the inner diameter of the second bearing fixing surface is 0.2 mm or less. [25] Bicycle bottom bracket assembly (10) according to claim 14, wherein the difference between the inner diameter of the second bearing passage surface and the inner diameter of the second bearing fixing surface is 0.1 mm or less. [26] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second bearing set (22b) is fixed to the second bearing fixing surface by press-fitting. [27] Bicycle bottom bracket assembly (10) according to claim 14, wherein the second bearing set (22b) is fixed to the second bearing fixing surface by adhesive bonding. [28] A bicycle bottom bracket assembly (10) according to claim 27, wherein an adhesive holding portion is formed on the second bearing fixing surface. [29] Bicycle bottom bracket set (10) according to claim 14, further comprising: a tubular member (20) that prevents the entry of foreign substances, wherein the first support bearing member (24a) further comprises a first tubular member attachment portion (38a) configured to attach a first end of the tubular member (20) thereto, and the second support bearing member (24b) further comprises a second tubular member attachment portion (38b) configured to have a second end of the tubular member (20) attached thereto.

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