A bicycle crank manufacturing mold and a bicycle crank

Abstract

This utility model belongs to the field of bicycle parts technology, and relates to a bicycle crank production mold and a bicycle crank. The mold includes an upper mold, a lower mold, a bottom bracket insert assembly, and a pedal insert assembly. The upper and lower molds together form a receiving cavity. The bottom bracket insert assembly is used to fit and lock together with the bottom bracket hole aluminum part in the crank preform. The pedal insert assembly is used to fit and lock together with the pedal hole aluminum part in the crank preform. The lower mold is equipped with an air inlet for supplying air to the crank preform. Its beneficial effect is that by fitting and locking the bottom bracket insert assembly with the bottom bracket hole aluminum part, then fitting and locking the pedal insert assembly with the pedal hole aluminum part, then placing the crank preform into the lower mold and closing it with the upper mold, and then placing the mold into a furnace for curing and molding, an integrated finished product of the crank, bottom bracket hole aluminum part, and pedal hole aluminum part is obtained. This solves the technical problem that using existing crank molds to produce cranks requires secondary processing, resulting in high production costs.

Description

Technical Field

[0001] This utility model relates to the field of bicycle parts technology, and in particular to a bicycle crank production mold and a bicycle crank. Background Technology

[0002] Existing carbon fiber bicycles typically use carbon fiber cranks to reduce weight. These cranks are manufactured using molds, and the production process generally involves two steps: First, a pre-formed crank body with layers of carbon fiber fabric is placed into a mold and cured to obtain a semi-finished crank. Second, the bottom bracket interface and pedal threaded holes are machined onto the semi-finished crank to obtain the finished crank. Cranks produced using this mold method require secondary machining to form the bottom bracket interface and pedal threaded holes, making the process cumbersome and time-consuming, resulting in high production costs for carbon fiber cranks.

[0003] Therefore, it is necessary to develop more efficient bicycle crank production molds to simplify the crank production process and shorten production time. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a bicycle crank production mold and a bicycle crank, which solves the technical problem that the production of cranks using existing crank molds requires secondary processing, resulting in high production costs.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0008] In a first aspect, this utility model provides a bicycle crank production mold for producing bicycle cranks, including an upper mold, a lower mold, a bottom bracket insert assembly, and a pedal insert assembly. The upper mold and the lower mold are closed together to form a cavity for placing the crank preform. The bottom bracket insert assembly and the pedal insert assembly are placed in the cavity. The bottom bracket insert assembly is used to interlock and lock with the bottom bracket hole aluminum part in the crank preform, and the pedal insert assembly is used to interlock and lock with the pedal hole aluminum part in the crank preform. An air inlet is installed on the top surface of the front end of the lower mold. One end of the air inlet is used to connect to an external air source, and the other end is used to communicate with the crank preform.

[0009] Optionally, the center axis insert assembly includes an upper center axis insert and a lower center axis insert. The upper center axis insert includes a head and a platform, and the lower center axis insert has a boss. The platform and the boss are respectively used to insert into the top and bottom of the aluminum part of the center axis hole. The head has an operating hole, and the boss has an internal threaded hole so that a bolt passes through the operating hole and is threaded into the internal threaded hole to close the aluminum part of the center axis hole.

[0010] Optionally, the pedal insert assembly includes an upper pedal insert and a lower pedal insert, which are respectively inserted into the top and bottom surfaces of the pedal hole aluminum part and threaded together to close the pedal hole aluminum part.

[0011] Optionally, the mold also includes a first insert, which is installed at the front end of the lower mold and presses above the air inlet. The rear end of the first insert is provided with a first arc-shaped part, which is used to abut against the front end of the crank preform. The top surface of the first insert protrudes from the top surface of the lower mold, and the bottom surface of the upper mold is provided with a first positioning groove at a position corresponding to the first insert.

[0012] Optionally, the mold also includes a second insert that covers the insert on the central shaft, and the lower end of the second insert is provided with a mounting groove that matches the head, and the bottom surface of the upper mold is provided with a second positioning groove for positioning the second insert.

[0013] Optionally, the mold also includes a third insert, which is installed at the rear end of the lower mold. The front end of the third insert is provided with a second arc-shaped portion, which is used to abut against the rear end of the crank preform. The top of the third insert protrudes from the top surface of the lower mold, and the bottom surface of the upper mold is provided with a third positioning groove for positioning the third insert.

[0014] Optionally, the accommodating cavity is provided in two.

[0015] Optionally, the bottom surface of the upper mold is provided with a fourth positioning groove for positioning the foot pedal insert.

[0016] Secondly, this utility model embodiment provides a bicycle crank, which is solidified and formed using the aforementioned bicycle crank production mold. The crank is a carbon fiber crank, with an aluminum part for the bottom bracket hole embedded at one end and an aluminum part for the pedal hole embedded at the other end. The aluminum part for the pedal hole and the aluminum part for the bottom bracket hole are integrally formed with the crank.

[0017] (III) Beneficial Effects

[0018] The beneficial effects of this utility model are as follows: This utility model provides a bicycle crank production mold and a bicycle crank. By employing an upper mold, a lower mold, a bottom bracket insert assembly, and a pedal insert assembly, the upper and lower molds together form the receiving cavity of the crank preform. The bottom bracket insert assembly can be fitted into the bottom bracket hole aluminum part on the crank preform and connected together by bolts. The pedal insert assembly can be fitted into and locked together with the pedal hole aluminum part in the crank preform. Compared to the prior art, by fitting the bottom bracket insert assembly into the bottom bracket hole aluminum part of the crank preform and tightening it with bolts, then fitting the pedal insert assembly into the pedal hole aluminum part of the crank preform and locking it together with threads, and then placing the entire crank preform into the lower mold and closing it with the upper mold, and then placing the mold into a high-temperature furnace for curing and molding, an integrated finished product of the crank, bottom bracket hole aluminum part, and pedal hole aluminum part can be obtained without secondary processing. This solves the technical problem of high production costs caused by secondary processing required when using existing crank molds to produce cranks. Attached Figure Description

[0019] Figure 1 This is an exploded view (front view) of the mold part of an embodiment 1 of the present invention, which is a production mold for a bicycle crank.

[0020] Figure 2 This is an exploded view of the mold for producing a bicycle crank according to the present invention and an embodiment 1 of the bicycle crank (the upper mold is not shown).

[0021] Figure 3 This is an exploded view (back view) of a bicycle crank production mold and a bicycle crank embodiment 1 of the present invention.

[0022] Figure 4 This is a schematic diagram of the mold and finished crank assembly of a bicycle crank production mold and a bicycle crank according to Embodiment 1 of this utility model.

[0023] Figure 5 This is a schematic cross-sectional view of a bicycle crank production mold and a bicycle crank according to Embodiment 1 of the present invention.

[0024] Figure 6 This is one of the structural schematic diagrams of the cylinder preform, the insert on the bottom axle, and the pedal insert assembly, which are embodiments of the present invention, of a bicycle crank production mold and a bicycle crank.

[0025] Figure 7 This is one of the structural schematic diagrams of the cylinder preform, the insert on the bottom axle, and the pedal insert assembly, which are embodiments of the present invention, of a bicycle crank production mold and a bicycle crank.

[0026] [Explanation of Labels in the Attached Image]

[0027] 1. Upper mold; 11. First positioning groove; 12. Second positioning groove; 13. Third positioning groove; 14. Fourth positioning groove;

[0028] 2. Lower mold;

[0029] 3. First insert; 31. First arc-shaped part;

[0030] 4. Second insert; 41. Mounting slot;

[0031] 5. Third insert; 51. Second arc-shaped part;

[0032] 61. Upper central inlay; 611. Head; 612. Stage; 62. Lower central inlay;

[0033] 7. Pedal insert assembly; 71. Upper pedal insert; 72. Lower pedal insert;

[0034] 8. Crankshaft preform; 81. Aluminum part for bottom bracket hole; 82. Aluminum part for foot pedal hole;

[0035] 9. Air intake nozzle. Detailed Implementation

[0036] To better explain and facilitate understanding of this utility model, a detailed description of its specific embodiments is provided below with reference to the accompanying drawings. In this document, directional terms such as "upper" and "lower" are used interchangeably with... Figure 1 With the orientation as a reference, the direction where the upper mold 1 is located is "up", the direction where the lower mold 2 is located is "down", the direction where the first insert 3 is located is "front", and the direction where the third insert 5 is located is "back".

[0037] This utility model provides a bicycle crank manufacturing mold and a bicycle crank. The mold includes an upper mold, a lower mold, a bottom bracket insert assembly, and a pedal insert assembly. The upper and lower molds are closed together to form a cavity for housing the crank preform. The bottom bracket insert assembly and the pedal insert assembly are placed in the cavity. The bottom bracket insert assembly is used to interlock and lock with the bottom bracket hole aluminum part in the crank preform, and the pedal insert assembly is used to interlock and lock with the pedal hole aluminum part in the crank preform. An air inlet is installed on the top surface of the front end of the lower mold. One end of the air inlet is used to connect to an external air source. One end is connected to the crank preform; compared with the existing technology, the bottom bracket insert assembly is embedded with the bottom bracket hole aluminum part of the crank preform and tightened with bolts, and then the pedal insert assembly is embedded with the pedal hole aluminum part of the crank preform and locked together with threads. Then the entire crank preform is placed into the lower mold and closed with the upper mold. Then the mold is placed in a high-temperature furnace for curing and molding, and an integrated finished product of crank, bottom bracket hole aluminum part and pedal hole aluminum part is obtained. No secondary processing is required, which solves the technical problem that the production of cranks using existing crank molds requires secondary processing, resulting in high production costs.

[0038] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0039] Example 1:

[0040] Reference Figure 1 and Figure 2 This embodiment 1 provides a bicycle crank production mold for producing bicycle cranks, including an upper mold 1, a lower mold 2, a pedal insert assembly 7, and a bottom bracket insert assembly. The crank referred to in this application is a carbon fiber crank.

[0041] See Figure 2 and Figure 3The upper mold 1 and the lower mold 2 both have grooves on their bottom surfaces, which together form a cavity for housing the crank preform 8. The bottom bracket insert assembly and the pedal insert assembly 7 are placed in the cavity. The bottom bracket insert assembly is used to engage and lock with the bottom bracket hole aluminum part 81 in the crank preform 8, and the pedal insert assembly 7 is used to engage and lock with the pedal hole aluminum part 82 in the crank preform 8. An air inlet 9 is installed on the front top surface of the lower mold 2. One end of the air inlet 9 is used to connect to an external air source, and the other end is used to communicate with the crank preform 8. The air inlet 9 is used to inject compressed gas into the crank preform 8 after mold closing. The compressed gas can be nitrogen or dry air, with a pressure range of 0.5–1.0 MPa.

[0042] It should be noted that the crank preform 8 can use a high-temperature resistant plastic core material, such as PEEK core material. Both the pedal end and the bottom bracket end of the crank preform 8 have openings. During the process of the operator layering epoxy resin-coated carbon fiber cloth onto the outer surface of the crank preform 8, the pedal hole aluminum parts 82 and bottom bracket hole aluminum parts 81 are simultaneously pre-embedded in the two openings, allowing these two aluminum parts to be initially installed with the crank preform 8. During pre-embedding, the surfaces of the pedal hole aluminum parts 82 and bottom bracket hole aluminum parts 81 can be sandblasted and coated with a layer of epoxy structural adhesive; then, the pedal hole aluminum parts 82 and bottom bracket hole aluminum parts 81 are inserted and fixed into the openings where carbon fiber has been layered. The pedal hole aluminum parts 82 and bottom bracket hole aluminum parts 81 are aluminum alloy parts with openings.

[0043] During production, the bottom bracket insert assembly is first fitted into the bottom bracket hole aluminum part 81 of the crank preform 8 and tightened with bolts. Then, the pedal insert assembly 7 is fitted into the pedal hole aluminum part 82 of the crank preform 8 and locked together with threads. The entire crank preform 8 is then placed into the lower mold 2 and closed with the upper mold 1. After closing the mold, 0.5MPa of dry air is injected into the crank preform 8 through the air inlet 9 and the pressure is maintained for 30 seconds. The mold is then placed in the furnace for curing and molding. The temperature is increased to 150℃ at a gradient of 5℃ / min, and the curing time is set to 45 minutes. After cooling, the mold is opened, and the integrated finished product of the crank, bottom bracket hole aluminum part 81 and pedal hole aluminum part 82 is taken out. No secondary processing is required, which solves the technical problem that the production of cranks using existing crank molds requires secondary processing, resulting in high production costs.

[0044] See Figure 6 and Figure 7In some feasible solutions, the central axis insert assembly includes an upper central axis insert 61 and a lower central axis insert 62. The upper central axis insert 61 includes a head 611 and a step 612. The lower central axis insert 62 is provided with a boss. The step 612 and the boss are respectively inserted into the top and bottom of the opening of the central axis hole aluminum part 81. The head 611 is provided with an operating hole, and the boss is provided with an internal threaded hole so that the bolt passes through the operating hole and is threadedly connected to the internal threaded hole to close the opening of the central axis hole aluminum part 81.

[0045] Both the upper insert 61 and the lower insert 62 of the central shaft are clearance-fitted with the aluminum part 81 in the central shaft hole, with a clearance of less than 0.1 mm. The bolt tightening torque is 5–8 N·m to ensure that the central shaft insert assembly and the aluminum part 81 in the central shaft hole are firmly joined together, preventing the aluminum part 81 in the central shaft hole from shifting. The top surface of the head 611 is also provided with an arrow mark to indicate the installation direction of the upper insert 61 of the central shaft.

[0046] See Figure 6 and Figure 7 The pedal insert assembly 7 includes an upper pedal insert 71 and a lower pedal insert 72, which are respectively inserted into the top and bottom of the opening of the pedal hole aluminum part 82 and threaded together to close the pedal hole aluminum part 82. The lower pedal insert 72 has internal threads, and the upper pedal insert 71 extends into the pedal hole aluminum part 82 and is threaded together with the lower pedal insert 72 to close the opening of the pedal hole aluminum part 82.

[0047] Continue reading Figure 3 and Figure 4 In some feasible solutions, the mold further includes a first insert 3, which is installed on the top surface of the front end of the lower mold 2 and presses against the air inlet 9. The rear end of the first insert 3 has a first arc-shaped portion 31, which is used to cooperate with the front end of the crank preform 8, and the gap between the two is less than 0.1mm. The top surface of the first insert 3 protrudes from the top surface of the lower mold 2, and the bottom surface of the upper mold 1 has a matching first positioning groove 11 at a position corresponding to the first insert 3. The bottom surface of the first insert 3 has multiple positioning protrusions, and the lower mold 2 has grooves at positions corresponding to the protrusions, with the positioning protrusions cooperating with the grooves.

[0048] like Figure 2 and Figure 5 As shown, the mold further includes a second insert 4, which covers the insert 61 on the central shaft and the central shaft end of the crank preform 8. The lower end of the second insert 4 is provided with a mounting groove 41 that matches the head 611, and the gap between the head 611 and the mounting groove 41 does not exceed 0.05 mm. The bottom surface of the upper mold 1 is provided with a second positioning groove 12 for positioning the second insert 4. The second insert 4 can be connected to the upper mold 1 by a screw, or it can be an independent component and not connected to the upper mold 1. Providing the second insert 4 on the central shaft insert assembly can help the central shaft insert assembly to be positioned more accurately in the receiving cavity.

[0049] See Figure 2 Furthermore, the mold also includes a third insert 5. The top surface of the rear end of the lower mold 2 has a groove, and the third insert 5 is installed in the groove. The front end of the third insert 5 has a second arc-shaped portion 51, which is used to mate with the rear end of the crank preform 8, and the gap between the two is less than 0.1 mm. The top of the third insert 5 protrudes from the top surface of the lower mold 2, and the bottom surface of the upper mold 1 has a third positioning groove 13 for positioning the third insert 5.

[0050] See Figure 3 The bottom surface of the upper mold 1 is provided with a fourth positioning groove 14 for positioning the foot pedal insert 71.

[0051] In this application, the top surface of the lower mold 2 is provided with grooves for positioning and installation at positions corresponding to the lower insert 62 of the central shaft, the lower insert 72 of the foot pedal, the first insert 3 and the third insert 5, which are not shown in the figure.

[0052] like Figure 1 and Figure 2 As shown, in actual production applications, there are two accommodating cavities, arranged side-by-side with intervals. Correspondingly, there are two of each of the following: first insert 3, second insert 4, third insert 5, bottom bracket insert assembly, and air inlet 9, allowing for the simultaneous production of a pair of bicycle cranks. The first insert 3, second insert 4, third insert 5, bottom bracket insert assembly, pedal insert assembly 7, upper mold 1, and lower mold 2 are all made of high-temperature resistant materials with a low coefficient of thermal expansion, capable of withstanding temperatures exceeding 200℃ and having a coefficient of thermal expansion of 23.6 × 10⁻⁶. -6 Aluminum alloy at / ℃.

[0053] See Figure 2 and Figure 5 The air inlet 9 is used to fill the crank preform 8 with compressed gas during the curing process. One air inlet 9 is Y-shaped, allowing compressed air from an external source to enter through both inlets and be combined before being supplied to the crank preform 8. The other air inlet 9 is approximately U-shaped, allowing compressed air from an external source to enter the crank preform 8 through both inlets. The interface of the air inlet 9 uses a G1 / 8 thread standard and is sealed with a fluororubber O-ring (not shown), with a pressure resistance ≥1.2MPa.

[0054] See Figure 2 and Figure 3 The air inlet 9 protrudes from the top surface of the lower mold 2, and the bottom surface of the first insert 3 is provided with a groove that matches the air inlet 9, which is used to position and avoid the air inlet 9.

[0055] It should be noted that the two bottom bracket holes 81 of the bicycle's pair of cranks have different shapes, so the shapes of the two bottom bracket insert assemblies are not exactly the same.

[0056] Example 2:

[0057] This embodiment 2 provides a bicycle crank, which is produced using the mold of embodiment 1. The crank is a carbon fiber crank, with a bottom bracket hole aluminum part 81 embedded at one end and a pedal hole aluminum part 82 embedded at the other end. The pedal hole aluminum part 82, the bottom bracket hole aluminum part 81 and the crank are integrally formed.

[0058] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0059] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0060] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A bicycle crank production mold for producing a crank of a bicycle, characterized by: The assembly includes an upper mold (1), a lower mold (2), a bottom bracket insert assembly, and a pedal insert assembly (7). The upper mold (1) and the lower mold (2) are closed together to form a cavity for placing a crank preform (8). The bottom bracket insert assembly and the pedal insert assembly (7) are placed in the cavity. The bottom bracket insert assembly is used to engage and lock with the bottom bracket hole aluminum piece (81) in the crank preform (8). The pedal insert assembly (7) is used to engage and lock with the pedal hole aluminum piece (82) in the crank preform (8). An air inlet (9) is installed on the top surface of the front end of the lower mold (2). One end of the air inlet (9) is used to connect to an external air source, and the other end is used to connect to the crank preform (8).

2. A mold for producing a bicycle crank as set forth in claim 1, characterized in that: The central shaft insert assembly includes an upper central shaft insert (61) and a lower central shaft insert (62). The upper central shaft insert (61) includes a head (611) and a platform (612). The lower central shaft insert (62) is provided with a boss. The platform (612) and the boss are respectively used to insert into the top and bottom of the opening of the central shaft hole aluminum part (81). The head (611) is provided with an operating hole. The boss is provided with an internal thread hole so that a bolt passes through the operating hole and is threadedly connected to the internal thread hole to close the central shaft hole aluminum part (81).

3. A mold for producing a bicycle crank as set forth in claim 2, characterized in that: The pedal insert assembly (7) includes an upper pedal insert (71) and a lower pedal insert (72), which are respectively inserted into the top and bottom of the opening of the pedal hole aluminum piece (82) and threaded together to close the pedal hole aluminum piece (82).

4. A mold for producing a bicycle crank as set forth in claim 1, characterized in that: The mold also includes a first insert (3), which is installed at the front end of the lower mold (2) and presses above the air inlet (9). The rear end of the first insert (3) is provided with a first arc-shaped part (31), which is used to abut against the front end of the crank preform (8). The top surface of the first insert (3) protrudes from the top surface of the lower mold (2), and the bottom surface of the upper mold (1) is provided with a first positioning groove (11) corresponding to the position of the first insert (3).

5. A mould for producing a bicycle crank as claimed in claim 4, characterized in that: The mold also includes a second insert (4), which covers the insert (61) on the central axis, and the lower end of the second insert (4) is provided with a mounting groove (41) adapted to the head (611). The bottom surface of the upper mold (1) is provided with a second positioning groove (12) for positioning the second insert (4).

6. A mould for producing a bicycle crank as claimed in claim 5, characterized in that: The mold also includes a third insert (5), which is installed at the rear end of the lower mold (2). The front end of the third insert (5) is provided with a second arc-shaped part (51), which is used to abut against the rear end of the crank preform (8). The top of the third insert (5) protrudes from the top surface of the lower mold (2), and the bottom surface of the upper mold (1) is provided with a third positioning groove (13) for positioning the third insert (5).

7. A mold for producing a bicycle crank as set forth in claim 1, characterized in that: The accommodating cavity has two parts.

8. A mold for producing a bicycle crank as set forth in claim 3, characterized in that: The bottom surface of the upper die (1) is provided with a fourth positioning groove (14) for positioning the pedal upper insert (71).

9. A bicycle crank, characterized by: The carbon fiber crank is integrally formed with the pedal hole aluminum piece (82) and the middle shaft hole aluminum piece (81).

Images