Bicycle component and manufacturing method thereof

The present invention relates to a component of a bicycle, particularly a component suitable for use in an assembly of a bicycle part to which a specific large stress is applied. The present invention also relates to a method for manufacturing such a component.

Throughout this specification, pedal cranks will be described as "components", but the intent of "components" is not pedal cranks, but pedals, such as seat support poles. It extends to bicycle components that have similar characteristics to cranks.

Various shapes, materials and manufacturing techniques are used in the prior art to achieve the goal of reducing weight as much as possible while ensuring (if not improving) strength and reliability properties. You can find pedal cranks of the type.

Due to the desire to manufacture lighter pedals and cranks, composite materials, especially composite materials formed from sheets of resin and plastic materials incorporating structural fibers, have come to be used.

Nevertheless, the peculiar stress generated when using the pedal crank, specifically the twisting force caused by the propulsion action when the cyclist steps on the pedal, is the same as before, so the bottom bracket pivot Alternatively, it becomes necessary to insert a metal member that serves as a connecting portion between the pedal pivot and the pedal crank body.

A first example using the technique described above is shown in Patent Document 1 by the same applicant as in this application, where the pedal crank body is a thermosetting composite in a mold with metal inserts. Obtained by molding the material.

In the molding process, a plastic composite is placed to cover the insert, covering most of the outer surface of the insert, leaving only a small portion to accommodate attachment to the support member. This support member also functions conveniently as a member for taking out. The material thus placed in the mold is heated until it hardens, after which the pedal crank is removed from the mold by moving the removal member. The pedal crank is then cooled to room temperature. In the final form, the insert is largely incorporated within the material forming the pedal crank body.

A second example of using a metal insert in a composite pedal crank body is disclosed in Patent Document 2. In this solution, the outer surface of the insert is provided with a set of molded discs that are spaced apart and incorporated into the composite material that forms the pedal crank body.<patcit num="1"><text>European Patent Application Publication No. 1281609</text></patcit><patcit num="2"><text>U.S. Pat. No. 6,202,506</text></patcit>

<p> However, the prior art shown in Patent Document 1 has a drawback that the composite material covering the insert tends to peel off from the wall surface of the insert during the cooling step. In fact, during cooling, both the metal material that makes up the insert and the composite material that makes up the pedal crank body shrink. The progress of delamination becomes more and more problematic as the coefficients of thermal expansion of these two materials differ. Such peeling means a decrease in the adhesion between the metal insert and the composite, resulting in a decrease in the strength and holding properties of the entire pedal crank.</p><p> On the other hand, in the prior art shown in Patent Document 2, the contact surface between the insert and the composite material can be increased, but still due to partial peeling between the material of the pedal crank body and the insert. It has drawbacks due to it. This peeling is a phenomenon seen during the curing process of the pedal / crank body material.</p><p> An object of the present invention is to provide a bicycle component in which a metal insert is housed in a seat of a main body, which can avoid peeling between the main body and the metal insert, and a method for manufacturing the same.</p>

<p> To achieve the above object, the first configuration of the present invention is composed of structural fibers incorporated in a substrate of a polymeric material, which is mechanically connected to at least one element of the bicycle to transmit force. It is a bicycle component equipped with a main body. And at least one seat having an open entrance on the outer surface of the bicycle component, a bottom that is less than or equal to the size of the entrance, and a wall surface that defines a cross section that does not increase in size from the entrance to the bottom. It comprises a section and at least one metal insert housed in the seat.</p><p> According to the first configuration, the shape and dimensions of the seat allow the insertion of the insert into the body of the component after the formation of the seat is complete, so that the material in the curing process The unfavorable result of peeling due to the different shrinkage of the can be avoided.</p><p> Preferably, the seat and the insert are paired with a connecting surface to facilitate the formation of a suitable and strong contact surface between the two parts, the seat and the insert, and even more preferably. An adhesive substance is placed between the two.</p><p> In addition, a groove, or preferably a thread, is provided between the insert and the seat to minimize shear stress, especially when the bicycle component is a pedal crank.</p><p> In fact, in a preferred embodiment, the seat has substantially female threads, the insert is shaped like a male thread, and the insert can be easily inserted by screwing.</p><p> In this preferred embodiment, the seat and insert conveniently form a plurality of areas of different outer shape, i.e., a tightly fitted connecting area without clearance, and a gap for accommodating the adhesive material. It is more preferable to have a region.</p><p> A second configuration of the present invention is a bicycle component (consisting of structural fibers incorporated in a substrate of a polymeric material, with a body that is mechanically connected to at least one element of the bicycle to transmit force (a bicycle component). It is the manufacturing method of 1; 100). Then, a step of manufacturing the main body of the bicycle component into a desired shape, a step of providing the main body with a seat having a size and shape capable of accommodating the metal insert, and a step of providing the main body with a seat having a size and shape capable of accommodating the metal insert. A step of manufacturing the metal insert and a step of inserting the metal insert into the seat from the outside of the main body.</p><p> According to the second configuration, the bicycle component of the first configuration can be manufactured, and in a preferred embodiment, the first step for manufacturing the main body can be performed by molding in a mold.</p><p> In such cases, the seat is manufactured using a master element coated with a release agent (detachment-enhancing substance) and the seed element is placed in the mold prior to the material of the body. It can be done by keeping it. After the molding of the main body in the mold is completed, the seed mold is removed from the main body with the help of the mold release agent.</p><p> To enable this last step, the seed element consists of a removable element, preferably a male threaded element so that an insert with a male threaded thread can continue to be inserted. Consists of.</p><p> The seat can also be obtained by removing the material by machining.</p>

Further features and advantages of the present invention will be further clarified by the following description of some preferred embodiments made with reference to the accompanying drawings.

Bicycle components according to an embodiment of the present invention are shown in FIGS. 1 to 3, and reference numerals 1 are attached to the entire components. This component is a bicycle pedal crank, and the term "pedal crank" is used herein to mean a bicycle component that has similar characteristics to a pedal crank, such as a saddle post. Generally, such components are considered to be capable of transmitting or withstanding such forces to which at least one force component, such as pulling, compressing and / or twisting, is applied. be able to.

The pedal crank 1 comprises an elongated body 2 having a first seat 4 at the end 3, and the first seat 4 has a pedal crank 1 mounted on a bicycle bottom bracket pivot (not shown). ), A first metal insert 5 is housed.

The opposite end 6 is provided with a second seat 7 that accommodates a second metal insert 8 for connecting a pedal (not shown).

The two inserts 5 and 8 have through holes 9 and 10, respectively, for connection to the bottom bracket pivot and pedal pivot, respectively. In this embodiment, the through hole 9 is square for connection to the bottom bracket pivot, while the through hole 10 is female threaded for connection to the threaded pedal pivot. .. In other embodiments, the holes for these connections may not be through holes and may have other geometries that match the shape of the bottom bracket and pedal pivot.

The body 2 is composed of structural fibers incorporated in a substrate of thermoplastic or thermosetting resin, while inserts 5 and 8 are made of a metallic material, preferably an aluminum alloy. Structural fibers are preferably carbon fibers that are irregularly arranged in the substrate. Alternatively, structural fibers are regularly arranged in the mold, for example in a single direction or vertically and horizontally in the form of a fabric, to form a layer with the desired properties along a particular direction. You can also do it. Structural fibers can be selected from the group consisting of glass fibers, aramid fibers, ceramic fibers, or any combination thereof.

In particular, as seen in FIGS. 2, 3, 3A and 3B, the seats 4 and 7 are the entrances 4a and 7b, the bottoms 4b and 7a and the wall surface open to the surfaces 2a and 2b of the body 2 of the pedal crank 1, respectively. It has 4c and 7c. These seats 4 and 7 are almost cylindrical (strictly speaking, the space inside the seat is cylindrical), so the dimensions of the entrances 4a and 7b are almost the same as the dimensions of the bottoms 4b and 7a, respectively, and the walls 4c and 7c The same circular cross section is defined from the entrances 4a and 7b to the bottoms 4b and 7a. Inserts 5 and 8 are also substantially cylindrical, matching the shapes of the corresponding seats 4 and 7, respectively.

The seats 4 and 7 and the inserts 5 and 8 have connecting surfaces that match each other, and each has a thread. Seats 4 and 7 have female threads 11 and 12, while inserts 5 and 8 have sites 13 and 14 in the shape of male threads.

As can be seen in the detailed view of FIG. 3A for the end 3 for connection to the bottom bracket pivot, the male threaded portion 13 of the insert 5 has no clearance between it and the female thread 11. It has a second connecting region 13a with a clearance between the connecting region 13a and the female screw 11, and thus the gap region 15 is defined in the second connecting region 13b. The thickness of the gap region 15 is substantially uniform, preferably between 0.1 and 0.05 mm, and is filled with an adhesive substance (adhesive). The first connection region 13a without clearance specifically has three contact threads with an average diameter, outer diameter and valley diameter larger than the threads of the second region 13b. ing. The first region 13a with such a larger diameter thread is adjacent to the end 5a opposite to the first screwed end 5b of the insert 5. Further, the insert 5 has an enlarged head 17 located in contact with the ring-shaped contact surface 19 formed on the main body 2. The square through hole 9 allows for connection with the bottom bracket pivot.

The above description of the end 3 for connecting to the bottom bracket pivot is similarly applicable to the end 6 for connecting the pedal crank to the pedal pivot, as seen in FIG. 3B. .. The male-threaded portion 14 of the insert 8 has a first connecting area 14a with no clearance with the female thread 12 and a second connecting area 14b with a clearance with the female thread 12. In this way, the clearance region 16 is defined in the second connecting region 14b. The thickness of the gap region 16 is substantially uniform, preferably between 0.1 and 0.05 mm, and is filled with an adhesive substance. The first connecting region 14a without clearance specifically has three contacting threads with an average diameter, outer diameter and valley diameter larger than the threads of the second region 14b. The first region 14a with such a larger diameter thread is adjacent to the end 8b opposite to the end 8a of the first screwing of the insert 8. Further, the insert 8 has an enlarged head 18 located in contact with the ring-shaped contact surface 20 formed on the main body 2. The square through hole 10 allows connection with the pedal pivot.

Note that the two inserts 5 and 8 are screwed counterclockwise onto the body 2 of the pedal crank 1 on the opposing surfaces 2a and 2b. This provides a convenient screwing action that attempts to screw the inserts 5 and 8 into the corresponding seats 4 and 7 when the pedal is depressed.

An example of a modified male-female threaded connection between this insert and the seat is shown in Figure 3C. In this modification, the female thread 61 has a first connecting area 61a with no clearance with the male threaded portion 63 of the insert 55 and a second connecting area with a clearance with the male threaded portion 63 to define the clearance area 65. It differs from the above embodiment in that it has 61b. The first connecting region 61a has three contacting threads having an average diameter, an outer diameter and a valley diameter smaller than the threads of the second region 61b. The first region 61a is located adjacent to the bottom 54b of the seat 54. The insert 55 has an enlarged head 67 located in contact with the ring-shaped contact surface 69 formed on the main body 2.

Figures 4, 5 and 6 show various variants of the pedal crank described above, unlike the pedal crank just described in that the seat and inserts have other contours. However, the seats and inserts are still contoured and provide space for accommodating adhesive material.

In the pedal crank of FIG. 4, the insert 88 and the corresponding seat 84 connected to the center of motion are different from the insert 89 and the corresponding seat 85 connected to the pedal.

As can be seen from FIG. 4B, the seat 84 has an initial cylindrical portion 84a and a female threaded end 84b. The corresponding insert 88 has a male threaded portion 88b that connects to the female threaded portion 84b of the seat portion 84 and a cylindrical portion 88a having a diameter slightly smaller than the diameter of the cylindrical portion 84a of the seat portion 84. ing. This defines a gap region 87 that conveniently accommodates the adhesive material.

The seat 85 and the corresponding insert 89 have a slightly tapered cylindrical shape. As can be seen from the details in FIG. 4C, the bottom 85a of the seat 85 is smaller in size than the entrance 85b, and the wall surface 85c defines a cross section in which the dimensions decrease from the entrance 85b to the bottom 85a.

In the pedal crank of FIG. 5, the seats 74, 75 and the inserts 78, 79 combined therein each have a substantially prismatic shape with a hexagonal cross section.

In the pedal crank of FIG. 6, the seats 94, 95 and their combined inserts 98, 99, respectively, to improve the retention of the inserts 98, 99 by the seats 94, 95 when twisted. It has a substantially cylindrical shape with a contact surface having a groove in the vertical direction.

It should be noted that changing the geometry of the insert and seat changes the distribution of force when the pedal is pressed, especially the distribution of torsional force. This creates a mechanical stress between the pedal crank body and the insert so as to reduce as much as possible the shear stress applied to the adhesive material located between the pedal crank body and the insert during the design phase. The dimensions of the outer shape for proper distribution are determined.

FIG. 7 shows yet another variant of the pedal crank of FIG. 1, a pedal crank 100 with spokes, commonly known as a right pedal crank, to pull the chain 1 One or more crowns (not shown) are combined.

In this pedal crank, the pedal crank body 102 has a first seat 104 at one end that houses a first insert 108 for connection to the center of motion, and a pedal at the opposite end. It has a second seat 105 in which a second insert 109 is housed for connection to. The first and second inserts 108, 109 are preferably inserts of the type described in FIG.

The pedal crank body 102 further includes a third seat 115 and a third insert 110, the third seat 115 and the third insert 110 as described in each of the drawings above. It has the same format and is located between the first insert 108 and the second insert 109. The third seat 115 and the third insert 110 are used to secure the crown that is integrally attached to the pedal crank 100. For this purpose, a non-penetrating (dead end, blind) threaded hole 111 accommodating the screwing means of the crown is formed in the third insert 110.

Further, the pedal crank 100 has four arms 113 or spokes at one end, and a seat 112 at each end of the spokes so that the crown can be fixed at four more points using screwing means. It is provided. In this pedal crank 100, the arm 113 and the pedal crank body 102 constitute a single body made of structural fibers incorporated into a substrate of a polymeric material such as a thermosetting or thermoplastic resin. are doing.

In the pedal crank 100, the seat 112 can be of the type described above, each having a size and shape capable of accommodating a metal insert, in which case the metal. The insert defines four fixing points for fixing the crown to the pedal crank body 102.

Yet another variation is also conceivable, where the pedal crank may include a seat with a different geometry, for example any combination of shapes shown in FIGS. 4-6.

Further, the insert may have a shape different from that of the seat portion in which the insert is housed, and may be, for example, a triangular prism-shaped insert housed in an arbitrary non-cylindrical seat portion.

In yet another variant, the insert-seat connection can also be made without the intervention of adhesive material, in which case retention is ensured solely by mechanical interference between the two parts. Further, the seat portion can be made non-penetrating, and the seat portion does not have to occupy the entire thickness of the main body as in the above-mentioned shape.

With reference to FIGS. 8-11, the steps for obtaining the pedal crank of FIG. 1 are shown below according to another preferred embodiment of the invention, the method of manufacturing bicycle components.

As can be seen from FIG. 8, a predetermined amount of polymeric material 148 containing structural fibers is placed within the first half (half mold) 122 of the mold 120. Further, in the first half 122, two seed type elements 144 and 146 coated with a mold release agent are installed, and two support elements 140 and 142 that also function conveniently as elements for removal are installed. Is held in place by The seed elements 144 and 146 are male-threaded inserts with enlarged heads 157 and 158, respectively, and the outer shape reverses the shape of the seats 4 and 5 to be obtained in the pedal crank 1. It is a type that has been made to.

In the subsequent steps, the second half 124 of the mold 120 is placed over the first half 122 and closed, and the material 148 fills the recesses (cavities) defined by the two halves 122, 124 of the mold 120. Make it flow. As can be seen in FIG. 12, the plasticized material 148 completely fills the cavity and completely surrounds the seed elements 144, 146 except for the enlarged heads 157, 158. Therefore, the enlarged heads 157 and 158 are not covered with any material.

Subsequently, the mold 120 is heated by a suitable known heating means 134 to cure and reticulate the polymer material, and to mold the pedal crank body 2 according to a desired shape.

Next, the mold 120 is opened, and the taking-out elements 140 and 142 are operated to take out the pedal / crank body 2. As already mentioned, seed type elements 144, 146 have enlarged heads 157, 158 not covered by the material. Therefore, these type elements 144 and 146 can be subsequently removed from the pedal crank body 2 by loosening the screws. This work is facilitated by a mold release agent that coats the seed elements 144, 146 prior to molding, and by partial delamination of material 148 due to heat shrinkage of the material during the cooling process. By removing the seed elements 144 and 146, the whole is made from a hardened material formed from structural fibers, resulting in a semi-processed product consisting of a pedal crank body 2 with two screw seats 4 and 5.

In the subsequent work shown in FIG. 11, it is covered with a layer of adhesive material, which has the geometric shape shown in FIGS. 3A and 3B, preferably a bicomponent epoxy resin. , Inserts 5 and 8 with male threads are inserted, respectively. Upon screwing, the adhesive material is arranged to fill the gaps 15 and 16 defined between the seats 4 and 7 and the inserts 5 and 8. At the end of the screwing process, the tight connection formed by the male threads 13a, 14a in contact with the female threads 11 and 12 allows the inserts 5 and 8 to be finally secured into the seats 4 and 7. Become.

Then, the drying step continues until the adhesive substance is polymerized, but it may be carried out at room temperature or by heating.

Finally, suitable holes 9 and 10 for connecting to the bottom bracket pivot and pedals are provided in the inserts 5 and 8 by machine tool known machining techniques.

Conveniently, the manufacturing methods described above allow for improved coupling between the insert and the pedal crank body, thanks to their particular shape. In fact, the insert is inserted into a seat that is already made of a reticulated and hardened polymeric material, allowing ideal connection by mechanical interference.

More conveniently, the manufacturing method described above makes it possible to improve the coupling force between the insert and the pedal crank body by utilizing the adhesive properties of the adhesive material as much as possible. In fact, the adhesive material is applied and dried after the pedal crank body and inserts are complete, so the pedal crank body and inserts may shrink during the adhesive material polymerization process. Absent.

In a variant of such a manufacturing method, the use of seed elements of different shapes, i.e., the use of seed elements shaped so that each seat can be manufactured according to the desired geometry. Can be considered. For example, for the fabrication of the seat 61 shown in FIG. 3B, the seed element is a cylindrical element with a thread that changes shape as shown in FIG.

Further, as yet another step of the above-mentioned manufacturing method, after inserting the insert into the corresponding seat, an underside is provided at the end opposite to the enlarged head so that the insert does not fall off the seat. It is conceivable to perform drawing work to create an undercut area.

In another variant of the manufacturing method described above, the seed element is omitted in the molding to obtain a single plate-shaped pedal crank body without holes, and this simple plate-shaped pedal crank body is used as a starting point. As a result, the seat portion can be formed by processing with a machine tool.

In yet another modification, it is conceivable that in molding, a layer of material is appropriately arranged and used in the mold for molding the pedal crank. Such a layer consists of structural fibers unidirectionally arranged in the substrate of the polymeric material, or consists of structural fibers arranged longitudinally and horizontally in the form of a woven fabric in the substrate of the polymeric material. This allows the pedal crank to be given certain physical-mechanical properties along a given direction.

Slightly smaller than the insert, at least in part, so that the shape of the seed element closely resembles the shape of the insert and creates a gap to accommodate the adhesive material when the insertion is complete. It should be noted that it is large.

In addition, a removable cover element may be attached to the insert to improve the appearance of the pedal crank when attached to the bicycle.

The shape of the seat and the metal insert can be any combination of the shapes shown above. For example, all of the shapes shown may be tapered or have a first portion (truncated cone or pyramidal cone) with a reduced cross section and an end (cylinder or prism) with a constant cross section. May be good. Further, in the truncated cone-cylindrical shape, a thread may be provided at the cylindrical portion, that is, the end portion. The inner surface of the seat and / or the outer surface of the insert may be created by any combination of curved and flat areas.

<figref num="1">It is a perspective view which shows the bicycle component which is one Embodiment of this invention.</figref><figref num="2">It is an exploded perspective view of the same component.</figref><figref num="3">It is a cross-sectional view of III-III of FIG.</figref><figref num="3A">It is an enlarged view which shows a part of FIG. 3 in detail.</figref><figref num="3B">It is an enlarged view which shows another part of FIG. 3 in detail.</figref><figref num="3C">It is an enlarged view which shows a part modification example of FIG. 3A.</figref><figref num="4">FIG. 4 is an exploded perspective view showing a modified example of the component.</figref><figref num="4A">FIG. 4 is a sectional view taken along line IV-IV of FIG.</figref><figref num="4B">It is an enlarged view which shows a part of FIG. 4A in detail.</figref><figref num="4C">It is an enlarged view which shows another part of FIG. 4A in detail.</figref><figref num="5">It is an exploded perspective view which shows another modification of the component.</figref><figref num="6">It is an exploded perspective view which shows the further modification example of the said component.</figref><figref num="7">It is a top view which shows the further modification example of the said component.</figref><figref num="8">It is a figure which shows the process for manufacturing the component | component of FIG. 1 in the manufacturing method of the bicycle component which is another embodiment of this invention.</figref><figref num="9">It is a figure which shows another process for manufacturing the component of FIG. 1 in the method of manufacturing the bicycle component which is another embodiment of this invention.</figref><figref num="10">It is a figure which shows the still another process for manufacturing the component of FIG. 1 in the method of manufacturing the bicycle component which is another embodiment of this invention.</figref><figref num="11">It is a figure which shows the still another process for manufacturing the component of FIG. 1 in the method of manufacturing the bicycle component which is another embodiment of this invention.</figref><figref num="12">It is a cross-sectional view of XII-XII of FIG.</figref>

Code description

1 Bicycle component (pedal / crank) 2 Bicycle component body 2a, 2b Outer surface of bicycle component (body) 3 One end of bicycle component 4,7 Seat 4a, 7b Seat entrance 4b, 7a Seat Bottom of the part 4c, 7c Wall of the seat 5,8 Metal insert 5b, 8a The first screwed end of the metal insert 5a, 8b The other end of the metal insert 6 The other end of the bicycle component 9 , 10 Connecting holes for metal inserts 11,12 Connecting surfaces for seats with female threads 13,14 Connecting surfaces for metal inserts with male threads 13a, 14a First connecting areas 13b, 14b Second connection area 15,16 Gap 17,18 Enlarged head 54 Seat 54a Seat entrance 54b Seat bottom 55 Metal insert 61 Seat connection surface with female thread thread 61a First connection Area 61b Second connecting area 63 Connecting surface of metal insert with male thread thread 65 Gap 67 Enlarged head 74,75 Seat 78,79 Metal insert 84,85 Seat 84a, 85b Seat Entrance 84b, 85a Bottom of seat 84b Seat connection surface with female thread 85c Seat wall 87 Gap 88,89 Metal insert 88b Connection surface of metal insert with male thread 94,95 Seat 98,99 Metal insertion Object 100 Bicycle component 102 Bicycle component body 104,105 Seat 108,109 Metal insert 110 Third metal insert 113 Arm 115 Third seat 120 Type 144,146 Type element