High-strength light-weight crankset structure

Abstract

The invention discloses a high-strength light-weight crankset structure, which comprises a first crankset and a second crankset which are coaxially fixed at one end of a crank, and is characterized in that the first crankset is provided with an annular disc body, and a plurality of convex tongues which extend inwards and are connected with the crank are arranged on the inner side of the disc body. The crankset and the crank are designed to be of a four-claw structure, the BCD value of the bolt distribution diameter is set to be 120 / 80-90 mm, and the overall structure is light while the strength is met.

Description

Technical Field

[0001] The invention relates to the field of cranksets, and in particular to a high-strength and lightweight crankset structure. Background Art

[0002] Bicycle chainrings usually have two conventional specifications, namely standard chainrings with a bolt distribution diameter of BCD130 and compressed chainrings with a bolt distribution diameter of BCD110. Standard chainrings have a larger bolt distribution diameter BCD value and good overall strength, but the overall weight of the crank and sprockets is high, which is not conducive to lightweighting and affects the comfort of the rider. Therefore, standard chainrings are no longer a mainstream choice in the market. Based on the standard chainring, the compressed chainring reduces the bolt distribution diameter BCD value to achieve the purpose of reducing the weight of the crank, but increases the torque at the connection between the chainring and the crank, reduces the overall strength of the chainring, and increases the risk of damage to the sprockets. In addition, most of the road bike chainrings reported by the market are insufficient in strength, and most of them appear in the compressed chainring specifications. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, an object of the present invention is to provide a high-strength and lightweight crankset structure, so as to achieve the purpose of lightweight while ensuring strength.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A high-strength and lightweight crankset structure comprises a first crankset and a second crankset coaxially fixed to one end of a crank. The first crankset has an annular ring-shaped ring body, and a plurality of tongues extending inwardly for connecting with the crank are arranged on the inner side of the ring body.

[0006] In a preferred embodiment of the present invention, a first connecting hole for a locking screw to pass through to lock the first chainring and the crank together is provided on the protruding tongue, and a second connecting hole for a locking screw to pass through to lock the second chainring and the crank together is also provided on the second chainring, the first chainring and the second chainring are coaxially arranged, and a plurality of the first connecting holes and the second connecting holes are distributed in a circle around the axis of the chainring.

[0007] In a preferred embodiment of the present invention, the bolt distribution diameter of the first crankset is 120 mm, and the bolt distribution diameter of the second crankset is in the range of 80 to 90 mm.

[0008] In a preferred embodiment of the present invention, the pitch circle of the second crankset is smaller than that of the first crankset.

[0009] In a preferred embodiment of the present invention, the first crankset is a 50T crankset.

[0010] In a preferred embodiment of the present invention, the plurality of tongues include a first tongue, a second tongue, which are arranged in a mirror image on one side of the crank, and a third tongue and a fourth tongue, which are arranged on the other side.

[0011] The beneficial effects of the present invention are:

[0012] The present invention provides a high-strength and lightweight crankset structure, which achieves lightweight overall structure while meeting strength requirements by designing the crankset and crank as a four-claw structure and setting the bolt distribution diameter BCD value to 120 / 80-90mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0014] Figure 1 It is an exploded view of the present invention.

[0015] Figure 2 This is a schematic diagram of the first chainring.

[0016] Figure 3 It is a structural schematic diagram of the first tooth plate.

[0017] Figure 4 It is a schematic diagram of the structure of the crank. DETAILED DESCRIPTION

[0018] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings. The above description is simplified for the convenience of describing the present invention, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as a limitation on the present invention.

[0019] The singular forms "a", "said" and "the" used in the specification include plural forms unless clearly indicated. The terms "include", "comprises" and "comprising" used in the specification indicate the presence of the claimed features, but do not exclude the presence of one or more other features.

[0020] In the specification, when an element is referred to as being “on,” “fixed” to, “connected to,” “engaged to,” or the like, the element may be directly on, fixed to, connected to, engaged to, or contacting the other element, or intervening elements may be present.

[0021] It is to be understood that although the terms "first", "second", etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, a first element may be referred to as a second element without departing from the teachings of the present application.

[0022] The following will describe exemplary embodiments of the present application with reference to the accompanying drawings. However, it should be understood that the present application can be presented in a variety of different ways and is not limited to the embodiments described below. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments. In all drawings, the same reference numerals represent the same or functionally identical elements.

[0023] Figure 1 A high-strength and lightweight chainring structure is shown, in which a first chainring 20 and a second chainring 30 constituting a flywheel structure are arranged at the end of a crank 10. In order to achieve lightweight of the entire flywheel structure, the first chainring 20 and the second chainring 30 are both designed as a central hollow structure, and the first chainring 20 is fixed to the crank 10 by a number of protruding tongues 2.

[0024] Figure 2 and Figure 3 The specific structure of the first toothed disc is shown, and a plurality of tongues 21 are placed on the annular disc body 20a of the first toothed disc 20 and extend toward the axial direction thereof. In this embodiment, the plurality of tongues 21 include a first tongue 21a, a second tongue 21b, a third tongue 21c and a fourth tongue 21d. A connecting hole 22 is provided on the first tongue 21a, the second tongue 21b, the third tongue 21c and the fourth tongue 21d for passing through the locking screw 1 to fix the first toothed disc 21 and the second toothed disc 30 on the claw 11. Correspondingly, the end of the crank 10 is provided with a first claw 11a, a second claw 11b, a third claw 11c and a fourth claw 11d matching the first tongue 21a, the second tongue 21b, the third tongue 21c and the fourth tongue 21d. The first claw 11a, the second claw 11b, the third claw 11c, and the fourth claw 11d are distributed in a mirror image on both sides of the crank 10. The first connecting hole 22a, the second connecting hole 22b, the third connecting hole 22c, and the fourth connecting hole 22d are distributed in a circle around the axis of the first crank plate 20, and the bolt circle distribution diameter BCD1 is 120mm. It can be understood that the second crank plate 30 has a similar structure to the first crank plate 20.

[0025] Combination Figure 4, the bolt circle distribution diameter BCD2 of the second chainring 30 ranges from 80 to 90 mm. Since the first chainring 20 is designed as a hollow structure 20b for the purpose of lightweighting, excessive torque may cause damage to the structure at the tongue 21. The theoretical torque M applied to each connecting hole 22 of the first chainring 20 is (FxL) / number of connecting holes, where FxL=(pitch circle-BCD) / 2, the pitch circle is the virtual circumference formed by the common tangent line between the chain 2 and the tooth profile 3 on the first chainring 20, and the bolt circle distribution diameter BCD is the radius of the virtual circumference formed by a number of connecting holes 22. Taking a 50T tooth plate as an example (pitch circle = 202.26mm), if a standard plate (BCD: 130) is used, the five-claw structure is: M = Fx (202.26-130) / 2 / 5 = 7.226F; if a compression plate (BCD: 110) is used, the four-claw structure is: M = Fx (202.26-110) / 2 / 4 = 11.533F; if the first tooth plate of the present invention (BCD: 120) is used, the four-claw structure is: M = Fx (202.26-120) / 2 / 4 = 10.283F. It can be seen that the first tooth plate 20 reduces the torque on the tooth plate by about 11% while maintaining the lightweight, thereby improving the strength and life of the tooth plate set.

Claims

1. A high-strength and lightweight crankset structure, comprising a first crankset and a second crankset coaxially fixed to one end of a crank, characterized in that: The first toothed disc has a disc body in an annular shape, and a plurality of tongues extending inwardly and used for connecting with the crank are arranged on the inner side of the disc body.

2. A high-strength and lightweight crankset structure as claimed in claim 1, characterized in that: The tongue is provided with a first connecting hole for a locking screw to pass through to lock the first chainring and the crank together, and the second chainring is also provided with a second connecting hole for a locking screw to pass through to lock the second chainring and the crank together. The first chainring and the second chainring are coaxially arranged, and a plurality of the first connecting holes and the second connecting holes are distributed in a circle around the axis of the chainring.

3. A high-strength and lightweight crankset structure as claimed in claim 2, characterized in that: The bolt distribution diameter of the first crankset is 120 mm, and the bolt distribution diameter of the second crankset is in the range of 80 to 90 mm.

4. A high-strength and lightweight crankset structure as claimed in claim 3, characterized in that: The pitch circle of the second chainring is smaller than that of the first chainring.

5. A high-strength and lightweight crankset structure as claimed in claim 3, characterized in that: The first chainring is a 50T chainring.

6. A high-strength and lightweight crankset structure according to any one of claims 1 to 6, characterized in that: The plurality of tongues include a first tongue, a second tongue, which are arranged in a mirror image on one side of the crank, and a third tongue and a fourth tongue, which are arranged on the other side.

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