Integrated five-claw hollow crank

Abstract

The utility model discloses an integrated five-claw hollow crank, which comprises a crank main body, a plurality of claw portions at one end of the crank main body, a weight-reducing cavity arranged in the crank main body, an avoiding hole formed at the end of the crank main body away from the claw portions, a mounting hole formed at the bottom end of the crank main body, and a crank back cylindrical part mounted on the mounting hole. An installation part is assembled in the weight-reducing cavity and used for mounting a pedal in cooperation with the avoiding hole. The installation part comprises a filling block assembled in the avoiding hole, and a threaded hole is formed in the middle of the filling block and corresponds to the avoiding hole. The utility model relates to the technical field of bicycle transmission components. Through the overall structural design, the utility model can cancel redundant parts such as independent disc claws and connecting bolts, and realize the coordinated improvement of deep weight reduction and structural strength.

Description

Technical Field

[0001] This utility model relates to the technical field of bicycle transmission components, specifically an integrated five-claw hollow crank. Background Technology

[0002] The crank and chainring are the core of a bicycle's power transmission system. They work together to effectively convert the rider's power into the bicycle's motion. The crank provides the power input, while the chainring amplifies or reduces this power in conjunction with the chain to adapt to different riding needs.

[0003] Currently, in traditional technology, the crank and crank jaws are mostly separate units, and the crank jaws are primarily assembled to the crank via bolts or welding. However:

[0004] 1. The bolted connection method results in a large number of parts, making it difficult to meet the overall lightweight requirements after assembly. Moreover, during long-term riding, vibration can easily cause the bolts to loosen, the crank arms to deform, and even pose a safety hazard of the crank arms separating from the crank arms.

[0005] 2. The welding method is prone to causing concentration issues, which can easily lead to cracking during long-term riding.

[0006] Therefore, this utility model provides an integrated five-claw hollow crank to solve the above problems. Utility Model Content

[0007] To address the shortcomings of existing technologies, this utility model provides an integrated five-claw hollow crank, which solves the aforementioned problems.

[0008] To achieve the above objectives, this utility model provides the following technical solution: an integrated five-claw hollow crank, comprising:

[0009] The crank body has multiple claws at one end, a weight-reducing cavity is provided inside the crank body, an avoidance hole is provided at the end of the crank body away from the claws, and a mounting hole is provided at the bottom end of the crank body for mounting the crank back cylinder.

[0010] The mounting component is assembled inside the weight reduction cavity and is used to install the foot pedal in conjunction with the clearance hole.

[0011] Preferably, the mounting component includes:

[0012] A filler block is assembled inside the clearance hole, and a threaded hole is provided in the middle of the filler block, which corresponds to the clearance hole.

[0013] Preferably, the crank body and the claw are integrally formed, and the number of claws is not less than three.

[0014] Preferably, each of the claw portions has a weight-reducing groove in the middle, and a threaded through hole is provided at the end of the claw portion away from the crank body.

[0015] Preferably, the crank body is elliptical in shape near the end of the filler block.

[0016] Preferably, the filling block and the inner wall of the weight reduction cavity are interference fit.

[0017] Beneficial effects

[0018] This invention provides an integrated five-claw hollow crank. Compared with the prior art, it has the following advantages:

[0019] This integrated five-jaw hollow crank, through its overall structural design, eliminates redundant parts such as independent disc claws and connecting bolts, achieving a synergistic improvement in both weight reduction and structural strength.

[0020] This integrated five-claw hollow crank, through the one-piece molding process of the crank body and the claw, can ensure the structural integrity of the claw and the crank body, greatly improve the coaxiality of the installation of the claw and the crank body, reduce riding vibration and power loss, is suitable for all vehicle transmission scenarios, and greatly reduces production costs.

[0021] This integrated five-jaw hollow crank, through the interference fit between the filler block and the weight reduction cavity, can enhance the hardness and wear resistance of the pedal connection part, solving the common problem of stripped threads in traditional cranks. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the entire utility model;

[0023] Figure 2 This is a side view of the present invention;

[0024] Figure 3 This is a schematic diagram of the removal structure of the filling block of this utility model;

[0025] Figure 4 This is a half-sectional structural diagram of the crank body and filler block of this utility model;

[0026] Figure 5 This is a schematic diagram of the assembly structure of the weight reduction cavity and the filling block of this utility model.

[0027] In the figure: 1. Crank body; 2. Claw part; 3. Weight reduction cavity; 4. Clearance hole; 5. Mounting hole; 6. Filler block; 7. Threaded hole; 8. Weight reduction groove. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1:

[0030] Please see Figure 1-5 A one-piece five-claw hollow crank, comprising:

[0031] The crank body 1 has multiple claws 2 at one end, a weight reduction cavity 3 is provided inside the crank body 1, an avoidance hole 4 is provided at the end of the crank body 1 away from the claws 2, and a mounting hole 5 is provided at the bottom end of the crank body 1 for mounting the crank back cylinder.

[0032] The mounting component is assembled inside the weight reduction cavity 3 and is used to install the foot pedal in conjunction with the clearance hole 4;

[0033] Please refer to Figure 3 In this embodiment, the crank body 1 and the claw 2 are integrally formed, and the number of claws 2 is not less than three.

[0034] In this embodiment, there are five claws 2, which are evenly arranged at one end of the crank body 1 and are formed by cold forging. The cold forging process refines the grain size and increases the density of the material, ensuring the structural integrity of the claws 2 and the crank body 1. At the same time, it can eliminate redundant parts such as independent disc claws and bolts, avoiding the risk of loosening and cracking, and also reducing the overall weight. It also takes into account the coaxiality of the claws 2 and the crank body 1, ensuring the overall power transmission efficiency.

[0035] In other embodiments, a cylindrical or conical central positioning protrusion can be added to the central area of ​​the claw to achieve cooperative positioning of the claw 2, depending on the positioning requirements.

[0036] More specifically, the crank body 1 can be made of high-strength aluminum alloy, magnesium alloy or carbon fiber reinforced composite material, so that the crank body 1 has good cold forging formability and mechanical properties, and its tensile strength and fatigue resistance can be further improved after cold forging and heat treatment.

[0037] Please refer to Figure 3 In this embodiment, each claw part 2 has a weight reduction groove 8 in the middle, and a threaded through hole is provided at the end of the claw part 2 away from the crank body 1.

[0038] More specifically, by setting the weight reduction groove 8, the overall weight reduction can be achieved to a greater extent without affecting the structural strength of the claw 2.

[0039] Please refer to Figure 4 In this embodiment, the weight-reducing cavity 3 is designed as a semi-through or fully through cavity to adapt to the vehicle structure.

[0040] Please refer to Figure 4 In this embodiment, the mounting component includes:

[0041] The filler block 6 is assembled inside the clearance hole 4. The filler block 6 has a threaded hole 7 in the middle, which corresponds to the clearance hole 4. The threaded hole 7 is used to connect the foot pedal.

[0042] Please refer to Figure 4 In this embodiment, the crank body 1 is elliptical in shape at the end near the filler block 6;

[0043] More specifically, by utilizing the shape characteristics of the end of the crank body 1 near the filler block 6, the structure of the crank body 1 can be optimized to adapt to the vehicle model. In other embodiments, the shape of the end of the crank body 1 near the filler block 6 can also be circular.

[0044] In this embodiment, the filling block 6 and the inner wall of the weight reduction cavity 3 are interference fit;

[0045] More specifically, the filler block 6 can be made of alloy steel, titanium alloy, high-strength aluminum alloy, or ceramic-reinforced metal matrix composite material to ensure the structural strength of the filler block 6. In this embodiment, the filler block 6 is introduced into the weight reduction cavity 3 by cold pressing or hot fitting with a press until the filler block 6 and the cavity wall of the weight reduction cavity 3 are tightly fitted to form an interference fit, thereby strengthening the hardness and wear resistance of the foot pedal connection and solving the common problem of stripped threads in traditional cranks.

[0046] Example 2:

[0047] This embodiment provides a method for producing an integrated five-claw hollow crank based on Embodiment 1: The steps are as follows:

[0048] S1: Cold forging billet. A suitable size aluminum alloy or other material billet is placed into the mold cavity and pressure is applied to forge a five-claw functional structure with "4 exposed claws 2 + 1 back ellipse" and a half solid crank in one go. Claw 2 is seamlessly connected to crank body 1.

[0049] S2: Mandrel drawing: The cold-forged half-solid crank blank is fixed in the drawing die. A high-strength alloy mandrel is inserted along the axis of the blank. Axial tension and radial pressure are applied through the die. As the mandrel is inserted deeper, the half-solid crank extends axially. The inner wall is supported by the mandrel to form a weight-reducing cavity 3 (semi-through or fully through). After the mandrel is drawn out, the hollow structure is formed without the need for subsequent mechanical hollowing.

[0050] S3: Post-forging heat treatment to optimize overall mechanical properties;

[0051] S4: CNC machining, precision machining of the heat-treated blank, including the end face of claw 2, the center positioning protrusion (if any), the assembly surface of the weight reduction cavity 3, and the threaded cylinder hole on claw 2, to ensure the accuracy and adaptability of key dimensions.

[0052] S5: Install the filler block 6, align the filler block 6 with the opening of the weight reduction cavity 3, and press it in with a press until the filler block 6 is tightly fitted to the inner wall of the end of the weight reduction cavity 3, forming an interference fit.

[0053] S6: Threading, CNC tapping is performed on the exposed end of the filler block 6 to form a threaded hole 7 and a threaded through hole at the end of the claw 2 away from the crank body 1.

[0054] Example 3:

[0055] This embodiment provides a method for producing an integrated five-claw hollow crank based on Embodiment 1: The steps are as follows:

[0056] S1: Hot forging billet. A suitable size aluminum alloy or other material billet is placed into the mold cavity and pressure is applied to forge a five-claw functional structure with "4 exposed claws 2 + 1 back ellipse" and a half solid crank in one go. Claw 2 is seamlessly connected to crank body 1.

[0057] S2: Pulling out the mandrel reduces the resistance to elongation. After the mandrel is pulled out, the hollow structure is formed without the need for subsequent mechanical hollowing.

[0058] S3: Stress-relief annealing improves dimensional stability and optimizes overall mechanical properties;

[0059] S4: CNC machining, precision machining of the heat-treated blank, including the end face of claw 2, the center positioning protrusion (if any), the assembly surface of the weight reduction cavity 3, and the threaded cylinder hole on claw 2, to ensure the accuracy and adaptability of key dimensions.

[0060] S5: Install the filler block 6, heat the crank body 1, and then insert the filler block 6 into the crank body 1 through the opening of the weight reduction chamber 3. After the crank body 1 cools down, the filler block 6 can be effectively positioned.

[0061] S6: Threading, CNC tapping is performed on the exposed end of the filler block 6 to form a threaded hole 7 and a threaded through hole at the end of the claw 2 away from the crank body 1;

[0062] Combining Embodiment 1, Embodiment 2, and Embodiment 3, the following excellent effects can be achieved:

[0063] 1. By using the integrated molding of the claw part 2 and the crank body 1, plus the hollow elongation of the mandrel, redundant parts such as independent disc claws and connecting bolts can be eliminated. Regardless of the number of disc claws (3, 4, 5 or more) or the positioning method (pure claw positioning or "claw part + center protrusion" positioning), it is possible to achieve a synergistic improvement in both weight reduction and structural strength, thus resolving the industry contradiction that "weight reduction inevitably leads to a decrease in strength".

[0064] 2. The integrated molding process ensures the structural integrity of the claw 2 and the crank body 1, and the mandrel elongation process achieves precise hollowing, which greatly improves the coaxiality of the claw 2 and the crank body 1, reduces riding vibration and power loss, and is suitable for all vehicle transmission scenarios.

[0065] 3. By using the interference fit between the filler block 6 and the weight reduction cavity 3, the hardness and wear resistance of the pedal connection part can be enhanced, solving the common problem of stripped threads in traditional cranks;

[0066] 4. By using the process of "integral molding + mandrel drawing + post-forging heat treatment", we can achieve mass production of different claw specifications (number of claws, spacing, positioning form), reduce production costs, and provide a standardized process solution for all similar designs of "integral claw + hollow".

[0067] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0068] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0069] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A one-piece five-claw hollow crank, characterized in that: include: A crank body (1) has multiple claws (2) at one end, a weight reduction cavity (3) is provided inside the crank body (1), a clearance hole (4) is provided at the end of the crank body (1) away from the claws (2), and a mounting hole (5) is provided at the bottom end of the crank body (1) for mounting the crank back cylinder; The mounting component is assembled inside the weight reduction cavity (3) and is used to install the foot pedal in conjunction with the clearance hole (4).

2. The integrated five-claw hollow crank according to claim 1, characterized in that: The mounting component includes: A filler block (6) is assembled inside the clearance hole (4). A threaded hole (7) is provided in the middle of the filler block (6), and the threaded hole (7) corresponds to the clearance hole (4).

3. The integrated five-claw hollow crank according to claim 1, characterized in that: The crank body (1) and the claw (2) are integrally formed, and the number of the claw (2) is not less than three.

4. The integrated five-claw hollow crank according to claim 1, characterized in that: Each of the claw portions (2) has a weight-reducing groove (8) in the middle, and a threaded through hole is provided at the end of the claw portion (2) away from the crank body (1).

5. The integrated five-claw hollow crank according to claim 1, characterized in that: The crank body (1) is elliptical in shape near the end of the filler block (6).

6. The integrated five-claw hollow crank according to claim 2, characterized in that: The filling block (6) and the inner wall of the weight reduction cavity (3) are interference fit.

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