Abstract:
A bicycle cogset manufacturing method includes: connecting a first and a second sprocket in different sizes with connecting members as a sprockets assembly in advance, where first and second inner portions of the first and second sprockets respectively have first insertion and second insertion members, and each of the insertion members are respectively provided with a first and a second positioning hole; transferring the sprockets assembly into a mold, and performing pouring to form a sprocket base, where an assembly hole is disposed in the center of the sprocket base, a plurality of connecting arms are arranged on an outer portion of the sprocket base, and the connecting arms clad the first insertion members and the second insertion members to form a cogset. In this way, modularization can be implemented to achieve objectives of preventing troublesome riveting, accelerating manufacture, and reducing product weight.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a bicycle sprocket, and in particular, to a method for manufacturing a bicycle cogset that can be modularized to increase the efficiency of manufacture and production and reduce a manufacturing cost. 
         [0003]    2. Description of Related Art 
         [0004]    Generally, a rear cogset of a variable-speed bicycle has multiple rear sprockets with different sizes assembled on it, and these sprockets are assembled together on a sleeve, where the sleeve is sleeved on a rear hub, and the rear hub is connected to a rear wheel of the bicycle. Pedaling pedals of the bicycle drives a front chainwheel to rotate, the front chainwheel is connected to the rear cogset by a chain hanging thereon, and the chain can be moved by a derailleur of the bicycle to move between two different sprockets of the rear cogset according to a different road condition, so as to drive the bicycle to move forward. 
         [0005]      FIG. 1  and  FIG. 2  show a bicycle cogset according to Taiwan utility model patent No. M451318, including a base  60 , a plurality of long fixing members  70  and short fixing members  74 , a large sprocket  80  with the largest outer diameter, a first sprocket  90 , a second sprocket  91 , a third sprocket  92 , and a fourth sprocket  93 . The base  60  has a cylindrical body  61 , an outer portion of the body  61  is provided with six supporting arms  62 , each of the supporting arms  62  has a first surface  63  and a second surface  64  that are opposite to each other, the second surface  64  is provided with a first step portion  641  and a second step portion  642  that are in a staircase shape, the thickness of the first step portion  641  is greater than that of the second step portion  642 , and each of the first step portion  641  and the second step portion  642  is provided with a through hole  65 . The first surface  63  of each of the supporting arms  62  is provided with the large sprocket  80 , and a mounting hole  81  is disposed to correspond to the through hole  65  of the first step portion  641 . The first sprocket  90 , the second sprocket  91 , the third sprocket  92 , and the fourth sprocket  93  are disposed sequentially in a direction of the second surface  64 . A plurality of mounting holes  901 ,  911 ,  921 , and  931  corresponding to the long fixing members  70  is respectively distributed annularly on the first sprocket  90 , the second sprocket  91 , the third sprocket  92 , and the fourth sprocket  93 . Each of the long fixing members  70  has a large-diameter portion  71 , a long shaft  72 , and a short shaft  73 , so that the first sprocket  90  is riveted by the long fixing members  70  through the mounting holes  901 , the fixing members  70  pass through the mounting holes  911  of the second sprocket  91 , the through holes  65  of the first step portions  641 , and the mounting holes  81  of the large sprocket  80 , and finally rivets the large sprocket  80  to the first surface  63 . 
         [0006]    Each of the short fixing members  74  has a large-diameter portion  75 , a long shaft  76 , and a short shaft  77 . The third sprocket  92  and the fourth sprocket  93  are riveted and fixed by the short shafts  77  of the short fixing members  74  by passing through the mounting holes  921  of the third sprocket  92 , and by the long shafts  76  of the short fixing members  74  by passing through the mounting holes  931  of the fourth sprocket  93  and the through holes  65  of the supporting arms  62 . As a result, the first sprocket  90 , the second sprocket  91 , the third sprocket  92 , the fourth sprocket  93 , and the large sprocket  80  are passed through and riveted by the plurality of long fixing members  70  and the plurality of short fixing members  74 , and are integrated together with the base  60 . 
         [0007]    In assembly, manual work is required, so that the short shaft  73  of the long fixing members  70  passes through the mounting hole  901  of the first sprocket  90 , and the long shaft  72  of the long fixing members  70  passes through the mounting hole  911  of the second sprocket  91  and the through hole  65  of the first step portion  641  and is riveted to the first surface  63 ; and the short shaft  77  of the short fixing members  74  passes through rocket  92 , and the long shaft  76  of each of the short fixing members  74  passes through the mounting hole  931  of the fourth sprocket  93  and the through hole  65  of the supporting arm  62  and riveted to the fourth sprocket  93  and the supporting arm  62 . It can be seen that the assembly process is quite time-consuming and troublesome, and the matching precision of the elements is difficult to control, which do not satisfy economical requirements. 
       SUMMARY 
       [0008]    In view of this, a main objective of the present invention is to solve the problems that a conventional rear bicycle cogset is time-consuming and troublesome in manufacture and assembly, and is not light in weight. 
         [0009]    To achieve the foregoing objective, the present invention discloses a method for manufacturing a bicycle cogset, comprising the following steps: 
         [0010]    Step (a1): preparing a first sprocket, where the first sprocket has a first outer portion and a first inner portion, the first outer portion is provided with a plurality of first teeth, the first inner portion is provided with a plurality of first insertion members, and each of the first insertion members is provided with a first positioning hole; 
         [0011]    Step (b1): preparing a second sprocket, where the second sprocket has a second outer portion and a second inner portion, the second outer portion is provided with a plurality of second teeth, the second inner portion is provided with a plurality of second insertion members, and each of the second insertion members is provided with a second positioning hole; 
         [0012]    Step (c1): preparing a plurality of connecting members, where each of the connecting members has a first pin and a second pin that are formed at different ends, the first pin of the connecting member is disposed in the first positioning hole of the first sprocket, and the second pin of the connecting member is disposed in the second positioning hole of the second sprocket, so as to connect the first sprocket and the second sprocket as a sprockets assembly; 
         [0013]    Step (d1): preparing a mold, and placing the sprockets assembly of Step (c1) into the mold; 
         [0014]    Step (e1): performing pouring material and molding, that is, pouring material into the mold to form a sprocket base, where an assembly hole is formed in the center of the sprocket base, a plurality of connecting arms are formed on a periphery of the sprocket base, and the connecting arms clad the first insertion members and the second insertion members; 
         [0015]    Step (f1): opening the mold to take out a finished cogset. 
         [0016]    Therefore, modularization can be implemented accurately and rapidly in manufacture, thereby completely preventing the time-consuming and troublesome manual riveting, reducing the cost, and achieving lightweight by controlling the weight of the elements, so that an economic benefit can be brought, and great industrial applicability can be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the disclosure, and wherein: 
           [0018]      FIG. 1  is an exploded three-dimensional diagram of a conventional bicycle cogset; 
           [0019]      FIG. 2  is a three-dimensional structural diagram of the conventional bicycle cogset; 
           [0020]      FIG. 3  is a flowchart according to a first embodiment of the present invention; 
           [0021]      FIG. 4  is an exploded three-dimensional diagram of a first sprocket, a second sprocket, and a pin according to the first embodiment of the present invention; 
           [0022]      FIG. 5  is a three-dimensional diagram of a finished cogset according to the first embodiment of the present invention; 
           [0023]      FIG. 6  is a sectional view of the finished cogset according to the first embodiment of the present invention; 
           [0024]      FIG. 7  is a flowchart according to a second embodiment of the present invention; and 
           [0025]      FIG. 8  is a schematic three-dimensional diagram of matching two semi-finished sprocket bases according to the second embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Detailed content and technical descriptions related to the present invention are further described below by using embodiments, but it should be understood that, the embodiments are merely exemplary, and should not be explained as limitations to the implementation of the present invention. 
         [0027]    Referring to  FIG. 3  to  FIG. 6 , the present invention discloses a method for manufacturing a bicycle cogset. A manufacturing process of a first embodiment of the present invention includes the following steps: 
         [0028]    Step (a1): Prepare a first sprocket  10 , where the first sprocket  10  has a first outer portion  11  and a first inner portion  12 , the first outer portion  11  is provided with a plurality of first teeth  13 , and the first inner portion  12  is provided with a plurality of first insertion members  14 . In this embodiment, the first insertion members  14  are arranged equally spaced on the first inner portion  12 , and each of the first insertion members  14  is provided with a first positioning hole  15 . 
         [0029]    Step (b1): Prepare a second sprocket  20 , where the second sprocket  20  is smaller than the first sprocket  10  and has a second outer portion  21  and a second inner portion  22 , the second outer portion  21  is provided with a plurality of second teeth  23 , and the second inner portion  22  is provided with a plurality of second insertion members  24 . In this embodiment, the second insertion members  24  are arranged equally spaced on the second inner portion  22 , and each of the second insertion members  24  is provided with a second positioning hole  25 . 
         [0030]    Step (c1): Prepare a plurality of connecting members  30 , where each of the connecting members  30  has a first pin  31  and a second pin  32  that are formed at different ends, and a flange  33  with an outer diameter larger than outer diameters of the first pin  31  and the second pin  32  is disposed in the center of the connecting members  30 . The first pin  31  of the connecting members  30  is disposed in the first positioning hole  15 , and the second pin  32  of the connecting members  30  is disposed in the second positioning hole  25 , so as to connect the first sprocket  10  and the second sprocket  20  as a sprockets assembly. In this case, the flange  33  is formed between the first sprocket  10  and the second sprocket  20  to form a space between the first sprocket  10  and the second sprocket  20 . 
         [0031]    Step (d1): Prepare a mold, and place the sprockets assembly of Step (c1) into the mold. 
         [0032]    Step (e1): Perform pouring material and molding, where one of thermoplastic resin, carbon fiber, or thermosetting resin materials is selected as a pouring material and poured into the mold. In this embodiment, nylon is used as a selected material, a molding temperature is about 240 degrees Celsius to 280 degrees Celsius according to the shape and size of the mold, and a molding time is within 30 seconds to 1 minute. A sprocket base  40  is formed according to the shape of the mold, an assembly hole  41  is disposed in the center of the sprocket base  40 , the assembly hole  41  is used for being engaged with a periphery of a sleeve (not shown in the figure) of a rear hub of a bicycle, a plurality of connecting arms  42  are formed on a periphery of the sprocket base  40 , and the connecting arms  42  clad the first insertion members  14  and the second insertion members  24 . 
         [0033]    Step (f1): Open the mold to take out a finished cogset. 
         [0034]    In the foregoing manufacturing method of the first embodiment of the present invention, because the sprocket base  40  is formed by pouring a material into a mold, in assembly, in advance, the first pin  31  of each of the connecting members  30  is disposed in the first positioning hole  15  of the first sprocket  10 , and the second pin  32  of each of the connecting members  30  is disposed in the second positioning hole  25  of the second sprocket  20 , so as to connect the first sprocket  10  and the second sprocket  20  to form a sprockets assembly and then the sprockets assembly are placed into the mold for molding. When the sprocket base  40  is formed, the first insertion members  14  of the first sprocket  10  and the second insertion members  24  of the second sprocket  20  are separately combined and solidified with the connecting arms  42  of the sprocket base  40 , and clad the connecting members  30  to be integrated together. Therefore, modularization can be implemented accurately and rapidly in manufacture, thereby completely preventing the time-consuming and troublesome manual riveting and achieving lightweight, so that the cost can be reduced, an economic benefit can be brought, and great industrial applicability can be achieved. 
         [0035]    Refer to  FIG. 7  in combination with  FIG. 4  and  FIG. 8 , which show a second embodiment of the method for manufacturing a bicycle cogset in the present invention. A manufacturing process includes the following steps: 
         [0036]    Step (a2): Prepare a first sprocket  10 , where the first sprocket  10  has a first outer portion  11  and a first inner portion  12 , the first outer portion  11  is provided with a plurality of first teeth  13 , and the first inner portion  12  is provided with a plurality of first insertion members  14 . In this embodiment, the first insertion members  14  are arranged equally spaced on the first inner portion  12 , and each of the first insertion members  14  is provided with a first positioning hole  15 . 
         [0037]    Step (b2): Prepare a second sprocket  20 , where the second sprocket  20  has a second outer portion  21  and a second inner portion  22 , the second outer portion  21  is provided with a plurality of second teeth  23 , and the second inner portion  22  is provided with a plurality of second insertion members  24 . In this embodiment, the second insertion members  24  are arranged equally spaced on the second inner portion  22 , and each of the second insertion members  24  is provided with a second positioning hole  25 . 
         [0038]    Step (c2): Prepare a plurality of connecting members  30 , where each of the connecting members  30  has a first pin  31  and a second pin  32  that are formed at different ends, and a flange  33  with an outer diameter larger than outer diameters of the first pin  31  and the second pin  32  disposed in the center of the connecting members  30 . The first pin  31  of the connecting members  30  is disposed in the first positioning hole  15  of the first sprocket  10 , and the second pin  32  of the connecting members  30  is disposed in the second positioning hole  25  of the second sprocket  20 , so as to connect the first sprocket  10  and the second sprocket  20  to form a sprockets assembly, and the flange  33  is formed between the first sprocket  10  and the second sprocket  20  to form a space between the first sprocket  10  and the second sprocket  20 . 
         [0039]    Step (d2): Prepare a mold for forming two opposite semi-finished sprocket bases  40   a  and  40   b , select one of thermoplastic resin, carbon fiber, or thermosetting resin materials as a material, and pour the material into the mold for the semi-finished sprocket base. In this embodiment, nylon is used as a selected material, a molding temperature is about 240 degrees Celsius to 280 degrees Celsius, and a molding time is about 30 seconds to 1 minute. A plurality of semi-finished sprocket bases  40   a  and  40   b  that correspond to each other are formed, assembly holes  41   a  and  41   b  are respectively disposed in the center of the semi-finished sprocket bases  40   a  and  40   b , the assembly holes  41   a  and  41   b  are used for being engaged with a periphery of a sleeve of a rear hub of a bicycle, a plurality of semi-finished connecting arms  42   a  and  42   b  are respectively formed on peripheries of the semi-finished sprocket bases  40   a  and  40   b , and two semi-finished sprocket bases  40   a  and  40   b  are combined face to face to form a complete sprocket base  40 . 
         [0040]    Step (e2): Prepare a shaping mold, place one of the two semi-finished sprocket bases  40   a  and  40   b , for example, the semi-finished sprocket base  40   a , into the shaping mold, place the sprockets assembly into the shaping mold, and place the other semi-finished sprocket base  40   b  into the shaping mold, so that the two corresponding semi-finished sprocket bases  40   a  and  40   b  clad the first sprocket  10  and the second sprocket  20  with one semi-finished sprocket base on the upper side and the other on the lower side, and two opposite semi-finished connecting arms  42   a  and  42   b  clad in opposite directions the first insertion member  14 , the second insertion member  24 , and the pin  30 . 
         [0041]    Step (f2): Combine and solidify the two semi-finished sprocket bases  40   a  and  40   b  into one finished sprocket base  40 . Generally, hot compacting may be performed on the shaping mold, or the combination may be implemented directly by an adhesive, so that the two semi-finished sprocket bases  40   a  and  40   b  clad the first sprocket  10  and the second sprocket  20  respectively from the upper side and the lower side, and two opposite semi-finished connecting arms  42   a  and  42   b  clad the first insertion member  14  of the first sprocket  10 , the second insertion member  24  of the second sprocket  20 , and the connecting members  30 . 
         [0042]    Step (g2): Open the shaping mold to take out a finished cogset. 
         [0043]    Because the two semi-finished sprocket bases  40   a  and  40   b  are formed by pouring a material into a mold which afterwards goes through high temperature and pressure, the first sprocket  10  and the second sprocket  20  are connected in advance by disposing the first pin  31  of the connecting members  30  into the first positioning hole  15  of the first sprocket  10 , and disposing the second pin  32  of the connecting members  30  into the second positioning hole  25  of the second sprocket  20 , and the two semi-finished sprocket bases  40   a  and  40   b  are placed into the shaping mold to clad the first sprocket  10  and the second sprocket  20  to form a finished cogset. Therefore, modularization of the process can be implemented accurately and rapidly, thereby completely preventing the time-consuming and troublesome manual riveting, so that the cost can be reduced, lightweight can be achieved due to no riveting, an economic benefit is brought, and great industrial applicability is achieved. 
         [0044]    Although the present invention is disclosed above by using preferred embodiments, a person skilled in the art should understand that the embodiments are merely used to describe the present invention and should not be explained as limitations to the scope of the present invention. It should be noted that, variations and replacements equivalent to the embodiments shall fall within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope of the claims below.