CN105143031A

CN105143031A - Crank spindle assembly and method of fabrication

Info

Publication number: CN105143031A
Application number: CN201480023652.5A
Authority: CN
Inventors: 克里斯托弗·P·多德曼; 史蒂芬·B·梅斯; 丹尼尔·康纳斯
Original assignee: Cycling Sports Group Inc
Current assignee: Cycling Sports Group Inc
Priority date: 2013-03-12
Filing date: 2014-03-04
Publication date: 2015-12-09
Also published as: EP2969729A4; WO2014164060A1; EP2969729A1

Abstract

A crank assembly for a bicycle is provided. The crank assembly includes an integrally formed unitary body. The body includes an arm first portion and an arm second portion extending on an angle from one end of the arm first portion. An enclosed cavity is disposed between the arm first portion and the arm second portion. The cavity has a first width at a first end in the arm first portion and a second width at an end of the arm second portion, the cavity and the arm first portion defining a first wall thickness in a first direction, the cavity and the arm second portion defining a second wall thickness in a second direction. The first wall thickness and the second wall thickness are substantially equal. A boss portion extends from an end of the arm second portion opposite the first arm portion.

Description

Crankshaft assembly and manufacture method

The cross reference of related application

This application claims the preceence of the U. S. application No.13/795075 that on March 12nd, 2013 submits to, the full text of this U. S. application is incorporated to herein by reference.

Technical field

Theme disclosed herein relates to bicycle and relates to the bicycle with crank shaft parts particularly.

Background technology

Bicycle---such as mountain bike and full terrain bicycle---can run into various landform and environmental conditions during operation.Therefore, the parts used in bicycle need to bear the impact caused by projection, rock and recess etc.This causes parts will be made up of firm material to be avoided damaging.But because the impact of lighter bicycle on the endurance of bicyclist is less, therefore other factors of such as such as weight and so on also can determine Material selec-tion.

In order to adapt to these factors, balance to be made on the Material selec-tion of parts with design.May expect the endergonic parts of such as such as front fork assembly and so on are made up of high strength steel.But, also undesirably may cause the added weight of steel part.In order to obtain high strength and the fork assembly of low weight, such as, propose the composite material of such as carbon composite and so on.Although the fork performance of being made up of these materials is good, their manufacture often costly.In addition, although composite material is comparatively firm, their metallic material elasticity in addition than traditional is little.Thus, the composite material of better performance is used can to increase cost further.

Bicycle comprises a large amount of sub-components, such as front steering pipe-fork assembly or crank-Shaft assembly.Each sub-component in these sub-components is made up of many parts usually.Such as, front fork assembly comprises steering tube, shoulder lid and one or more suspension fork.Although manufacture independent parts may expect to allow the Material selec-tion of parts and the alerting ability of design aspect, this causes adverse influence to the manufacturing cost of bicycle.

Therefore, although existing bicycle is applicable to its desired use, particularly still there are the needs of improvement at the manufacture view of parts, to keep or to reduce the number of parts while improving desired properties.

Summary of the invention

According to an aspect of the present invention, a kind of crank assemblies for bicycle is provided.This crank assemblies comprises integrated integral type body.This body comprises the first arm.The second arm is angularly extended with from one end of the first arm.Enclosed cavity is provided with between the first arm and the second arm.The first end place of this chamber in the first arm has the first width and has the second width in the end of the second arm.This chamber and the first arm define the first wall thickness in a first direction, and this chamber and the second arm define the second wall thickness in a second direction, wherein, the first wall thickness and the second wall thickness roughly equal.Boss portion is extended with from the end contrary with the first arm of the second arm.

According to a further aspect in the invention, a kind of crank assemblies for bicycle is provided.This crank assemblies comprises first arm with the first width.Be extended with the second arm from the first arm, this second arm has first end and the second end, and wherein, this first end has the second width, and this second end has the 3rd width, the 3rd width than the second width and the first width large.Be extended with enclosed cavity from the first arm to the second arm, this chamber coordinates to limit the first wall thickness with the first arm and the second arm, and this first wall thickness is roughly consistent along the first arm and the length of the second arm.Boss portion is extended with from the second end.

These and other advantage and feature following description in conjunction with the drawings will become more obvious.

Accompanying drawing explanation

Point out especially in the claims at the conclusion of the specification and require that clearly to be regarded as theme of the present invention.Aforementioned and other feature and advantage of the present invention following detailed description in conjunction with the drawings and become obvious, in the accompanying drawings:

Fig. 1 is the side plan view diagram of bicycle according to the embodiment of the present invention;

Fig. 2 is the partial side planar view diagram of the bicycle of Fig. 1;

Fig. 3 is the perspective view illustration of the integral type steering tube-shoulder lid embodiment for the bicycle of Fig. 1;

Fig. 4 to Fig. 6 is the perspective, cut-away view diagram of the embodiment of the integral type steering tube-shoulder lid of Fig. 3;

Fig. 7 to Figure 10 is the diagram of the integral type steering tube-shoulder lid-blade embodiments for the bicycle of Fig. 1;

Figure 11 to Figure 16 is the diagram of another integral type steering tube-shoulder lid embodiment of bicycle for Fig. 1;

Figure 17 to Figure 22 is the diagram of another integral type steering tube-shoulder lid embodiment of bicycle for Fig. 1;

Figure 23 to Figure 28 is the diagram of another integral type steering tube-shoulder lid-blade embodiments of bicycle for Fig. 1;

Figure 29 to Figure 30 is the diagram for the integral type steering tube-shoulder lid-blade of the bicycle of Fig. 1 or another embodiment of integral type steering tube-shoulder lid;

Figure 31 to Figure 38 is the diagram of the process for the manufacture of integral type steering tube-shoulder lid-fork according to the embodiment of the present invention;

Figure 39 to Figure 44 be according to the embodiment of the present invention for the manufacture of the diagram of process with another integral type steering tube of single fork-shoulder lid-fork;

Figure 45 is the side plan view in partial cross section's form of the steering tube-shoulder lid-fork of manufactured Figure 44;

Figure 46 to Figure 48 is the diagram of the blade insert in the steering tube-shoulder lid-fork of assembling Figure 45;

Figure 49 to Figure 50 is the perspective view illustration of the steering tube-shoulder lid-fork of completed Figure 48;

Figure 51 is the perspective view illustration of substituting completed steering tube-shoulder lid-fork;

Figure 52 is the exploded perspective view diagram of the crank assemblies embodiment of bicycle for Fig. 1;

Figure 53 to Figure 60 is the crank-arm of integral type of crank assemblies for the manufacture of Figure 52 and the diagram of the process of shaft component;

Figure 61 to Figure 66 is the crank-arm of the integral type of Figure 55 and Figure 56 and the diagram of shaft component;

Figure 67 to Figure 71 is the crank-arm of the integral type of Figure 57 and Figure 58 and the diagram of shaft component;

Figure 72 to Figure 76 is the crank-arm of the integral type of Figure 51 and the diagram of shaft component;

Figure 77 to Figure 80 be Figure 60 just insert the crank-arm of the integral type of connector and the diagram of shaft component;

Figure 81 to Figure 87 is the crank arm of the integral type that the secondary operation of Figure 60 has completed and the diagram of shaft component;

Figure 88 to Figure 89 is the crank-arm of integral type and the diagram of shaft component of another embodiment as the end-enclosed for making hole of Figure 52;

Figure 90 to Figure 91 is the crank-arm of another integral type and the diagram of shaft component of crank assemblies for Figure 52;

Figure 92 to Figure 99 is the diagram of the Part II of the crank arm of crank arm assembly for Figure 52;

Figure 100 to Figure 101 is the diagram of the crank assemblies according to another embodiment of the present invention; And

Figure 102 be Figure 100 to Figure 101 have one and the section drawing of the crank assemblies in the axle portion of integral type.

Detailed description is described embodiments of the present invention and advantage and feature by example with reference to accompanying drawing.

Detailed description of the invention

Fig. 1 is the illustrative embodiments of bicycle 100, and bicycle 100 has cycle frame 105, and cycle frame 105 is configured to receive front-wheel 110 and trailing wheel 115.Each wheel comprises respectively by the inflatable tyres 112,114 of wheel rim 116,118 supporting.Vehicle frame 105 comprises front waist section 120 and rear section 125.Front waist section 120 comprises head tube 130, and head tube 130 is configured to and is sized to receive front assembly 135 and allow the rotary freedom between the steering tube 140 in head tube 130 and front assembly 135.Front waist section 120 is attached to front-wheel 110 by front assembly 135.As will be discussed in more detail below, front assembly 135 can be arranged in some different embodiments, and these embodiments include but not limited to: integral type steering tube-shoulder lid-two blade rigid fork devices, integral type steering tube-shoulder lid-single rigidity fork device, integral type steering tube-shoulder lid arrangement, integral type steering tube-shoulder lid-two blade suspension fork devices and integral type steering tube-shoulder lid-one blade suspension fork device.

Steering tube 140 is connected with handlebar 145 makes front-wheel 110 turn to allow bicyclist via front assembly 135.Handlebar 145 has handle and hand braking actuator (not shown) usually.In the opposite ends of vehicle frame front waist section 120, vertically directed back seat supporting member 160 is attached at least one in front waist section 120 and rear section 125 regularly, thus provides supporting for seat 165.Front waist section 120 is provided with the crank assemblies 170 be positioned at below seat 165.As will be discussed in more detail below, crank assemblies 170 comprises Part I, the shaft that this Part I has the first arm and extends from this first arm.This axle is connected with second arm contrary with the first arm.The end of crank arm is connected with pedal (not shown).Crank assemblies 170 connects rear wheel gear assembly (not shown) via chain or other suitable components.

Rear section 125 is attached to front waist section 120 by pair of links 172,174 and rear-suspension system 175.Rear section 125 comprises pipe 180 and lower pipe 185, and trailing wheel 115 is connected to front waist section 120 by upper pipe 180 and lower pipe 185.Should be understood that, connecting rod 172,174 and rear suspension 175 pivotable, thus allow rear section 125 to move independently in the plane identical with front waist section 120.Two wheels 110,115 that such bicycle---sometimes referred to as full suspension type---is bicycle 100 provide absorption and the decay of energy.In substituting embodiment, rear suspension 175 can be saved to produce the bike type sometimes referred to as hard trailer, and rear section 125 will be attached to front waist section 120 regularly.

Now with reference to Fig. 2, front assembly 135 is described.Front assembly 135 comprises steering tube 140, and steering tube 140 is coupled in head tube 130 and rotates.Be extended with to provide the shoulder lid 190 with the joint of fork 192 from the bottom of steering tube 140.Fork 192 is connected with the hook pawl 194 contrary with takeing on lid 190.Hook pawl 194 and comprise the groove being sized to the wheel shaft 119 receiving front-wheel 110.As will be discussed further below, fork 192 can be connected in the both sides of front-wheel 110.In the present embodiment, can in conjunction with single suspension system, or every side of fork 192 all can have independent suspension system.The fork 192 with suspension can also be arranged on the such as left side (even if lack " leg " or " blade ", being still called as " fork "), only side of bicycle, and this is sometimes referred to as " left handed ".

During operation, front assembly 135 absorbs the large energy caused because of the shock on front-wheel 110.Therefore, expect front assembly 135 not only enough firm be subject to live to clash into, enough flexibles to be to avoid because clashing into the damage that causes but also lighter in weight.Integral type is shown in Fig. 3 to Fig. 6 and the embodiment of all-in-one-piece steering tube-shoulder lid 195.As used herein, term " integral type " and " integral type " refer to use monomer, seamless and continuous print material carrys out multiple funtion parts of forming member.In the exemplary embodiment, the parts of front assembly 135 are by alumina-bearing material---such as but not limited to 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.

In embodiment shown in Figure 3, integral type steering tube-shoulder lid 195 comprises steering tube 140, and steering tube 140 has axial hole 196.The shoulder lid 190 with the first protrusion 198 and the second protrusion 200 is extended with from an end of steering tube 140.Protrusion 198,200 comprises arm 206,208 separately, and arm 206,208 angularly extends away from steering tube 140 and ends at flange 210,212.In each flange 210,212, be formed with opening 202,204, opening 202,204 is sized to receiving suspension fork.Protrusion 198,200 angularly extends relative to the axis of steering tube 140.

Integral type steering tube-shoulder lid 195 by three-dimensional (3D) forging by metal as aluminium---include but not limited to such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.Aluminium compares the advantage that compound material provides following aspect: aluminium is high strength and the material of high tenacity and relative lightweight.As will be discussed in more detail below, 3D forging permission metalwork is molded into and makes these goods be hollow, and inner and outer wall can bend along any direction in three-dimensional simultaneously.

It is such as solid protrusion 198,200 that integral type steering tube-shoulder lid 135 can have, such as shown in Figure 4.As mentioned above, the weight of the parts reduced on bicycle 100 is expected.Another embodiment of integral type steering tube-shoulder lid 135 has been shown in Fig. 5.In the present embodiment, in arm 206, be formed with the hole 214 between opening 202 and axial hole 196, in arm 208, be formed with the hole 216 between opening 204 and axial hole 196.Should be understood that, hole 214,216 alleviates the weight of integral type steering tube-shoulder lid 135.In the embodiment of Fig. 5, after the forging of integral type steering tube-shoulder lid 135, define hole 214,216 by machine operations via opening 202,204.

Another embodiment of integral type steering tube-shoulder lid 135 has been shown in Fig. 6.In the present embodiment, between the end 219 and opening 202 of flange 210, the 3rd hole 218 is formed with.Similarly, between the end 222 and opening 204 of flange 212, the 4th hole 220 is formed with.In one embodiment, the 3rd hole 218 and the 4th hole 220 respectively with hole 214 and hole 216 coaxial.In another embodiment, hole 218,214 is formed with same machine operations and hole 220,216 is formed with same machine operations.

Integral type is shown and another embodiment of all-in-one-piece steering tube-shoulder lid-blade 222 in Fig. 7 to Figure 10.Similar with integral type steering tube-shoulder lid 135, integral type steering tube-shoulder lid-blade 222 comprises the steering tube 140 with axial hole 196.The shoulder lid 190 with the first protrusion 198 and the second protrusion 200 is extended with from steering tube 140.The first blade 224 and the second blade 226 is extended with respectively along the direction away from steering tube 140 from protrusion 198,200.In one embodiment, the axis of blade 224,226 and the axis of steering tube 140 almost parallel.Blade 224,226 comprises axial hole 228,330 separately, and axial hole 228,330 is unlimited on the end contrary with shoulder lid 190.In one embodiment, porose 232 are formed through the outside of blade 224 and outside through blade 226 forms porose 234.Should be understood that, similar with the embodiment shown in Fig. 6, hole 232,234 can extend through the first protrusion 198 and the second protrusion 200 in axial hole 196.Similar as above, integral type steering tube-shoulder lid-blade 222 by three-dimensional (3D) forging by metal as aluminium---comprise such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.

Similar with the embodiment shown in Fig. 2 to Figure 10, the integral type and all-in-one-piece steering tube-shoulder lid-fork 262 that are arranged for single fork 192 can be formed, as shown in Figure 11 to Figure 28 by 3D forging.In embodiment shown in Figure 11 to Figure 16, steering tube-shoulder lid-fork 262 comprises steering tube 140, and wherein, shoulder lid 264 extends from an end of steering tube 140.Shoulder lid 264 has single protrusion 266, and protrusion 266 has single flange 268 on the end contrary with steering tube 140.Flange 268 comprises opening 270, and opening 270 is sized to receives suspension fork (not shown).In the present embodiment, flange 268 also has angled relative to top surface 276 274 surfaces 272 arranged.Angled surface 272 provides the scheme allowing to form hole 278 in protrusion 266.As mentioned above, hole 278 helps the weight alleviating steering tube-shoulder lid-fork 262.

Embodiment shown in Figure 17 to Figure 22 shows the integral type steering tube-shoulder lid-fork 262 of the shoulder lid 264 with steering tube 140 and band protrusion 266.In the present embodiment, an end of protrusion 266 is provided with flange 278.Flange 278 comprises lower surface 280 and upper surface 282, lower surface 280 with upper surface 282 almost parallel and respectively with the axis 284 in hole 196 and axis 286 less perpendicular of opening 270.Flange 278 is configured to extend shorter distance from the lower surface 288 of steering tube 140.This set provides larger skin area in the opening 270 of flange 278.May expect that larger skin area is to strengthen integral type steering tube-shoulder lid-fork 262 and the connection such as between suspension fork (not shown).Because lower surface 280 extends farther, therefore hole 290 can be formed through the external diameter of flange 278.The second hole 292 is also formed with further expendable weight in protrusion 266.Should be understood that, hole 290,292 can be formed with same operation and have identical overall shape, or can be of different sizes and/or shape.

Embodiment shown in Figure 23 to Figure 28 shows the integral type steering tube-shoulder lid-fork 262 of the shoulder lid 264 with steering tube 140 and band protrusion 266.In the present embodiment, roughly blade 294 is extended with away from the direction of steering tube 140 from the edge, an end of protrusion 266.Blade 264 comprises the opening 296 extending through blade 264.Blade 264 forms part integral type steering tube-shoulder lid-fork 262 being connected to wheel 110 of suspension fork (not shown).Should be understood that, blade 264 can also be tapered with the rigidity fork formed as discussed in more detail below.Similar with above embodiment, the first hole 290 can be formed in the external diameter of blade 264 and the second hole 292 can be formed in protrusion 266, as mentioned above.

In some embodiments, steering tube 140 comprises hole 196.Hole 196 can be the through hole shown in the embodiment of such as such as Figure 13 and Figure 19.Such as, as shown in the embodiment of such as Fig. 4 to Fig. 6 and Figure 25, hole 196 can have closed end, and it is sometimes referred to as blind hole.Similarly, as shown in Fig. 3 to Fig. 6 and Figure 11 to Figure 28, blade 224,226,294 and flange 210,212,268 can have pass through openings 202,204,270,296.As shown in Figure 30, opening 202,204,270,296 can also have closed end.

The different embodiments of the end configuration of steering tube 140, blade 224,226,294 and flange 210,212,268 are discussed with reference to Figure 29 and Figure 30.As mentioned above, hole 196 can have and shoulder lid 190,264 adjacent closed ends 298.In the exemplary embodiment, closed end 298 can be formed during 3D forging process.Such as, closed end 298 can also pass through secondary operation---such as by first form through hole and secondly by Member Welding on end---formed.By making the end 298 in hole 196 close, can provide more by force and harder configuration aspects acquisition advantage.Should be understood that, in some embodiments, the open end in hole 196 may be needed to provide less weight.

Similar with hole 196, opening 202,204,270,296 also can have closed end 300.In the exemplary embodiment, closed end 300 is formed during the 3D forging process of blade or flange.Such as, closed end 300 also can pass through secondary operation---such as by first form through hole and secondly by Member Welding on end---formed.Similar with the end 298 closed, by having closed end 300, can provide more by force and harder configuration aspects acquisition advantage.Should be understood that, in some embodiments, the open end of opening 202,204,270,296 may be needed to provide less weight or for the spring of suspension and the installation of damping components.

It is to be further understood that, when not deviating from the desired extent of required invention, according to the desired properties of end application, steering tube 140, blade 224,226,294 and flange 210,212,268 can be arranged to the combination in any with open end 298 and closed end 300.Similarly, when not deviating from the desired extent of required invention, according to the desired properties of end application, protrusion 198,200,266 can comprise hole, or can be solid.

Although it is to be further understood that a part---such as blade 224,226 and steering tube 140---for a part for a part for integral type steering tube-shoulder lid 135, integral type steering tube-shoulder lid-blade 222 and integral type steering tube-shoulder lid-fork 262 to be described as general cylindrical shape by embodiment herein.But this is for exemplary purpose and when not deviating from the desired extent of required invention, other shapes also can be suitable or desirable.

Turn to Figure 31 to Figure 38 now, forge the method forming integral type steering tube-shoulder lid-fork 236 to utilizing multistage three-dimensional (" 3D ") and be described.Except suspension fork rigid leg substitutes, integral type steering tube-shoulder lid-fork 236 covers with steering tube-shoulder-and blade 222 is similar.Integral type steering tube-shoulder lid-fork 236 forms being rigidly connected between wheel 110 and handlebar 145.Should be understood that, the multistage 3D forging method forming integral type steering tube-shoulder lid-fork 236 can also be used to be formed steering tube-shoulder lid 135 and the steering tube-shoulder lid-blade 222 of integral type.

The method starts from blank 238 as shown in Figure 31, blank 238 by metal as aluminium---comprise such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.Blank is forged into formation the first protrusion 240 and the second protrusion 242 as shown in Figure 32 subsequently.Next, the blank 238 through forging utilizes 3D forging process to process and extends the second protrusion 242, thus forms the second microscler protrusion 246 (Figure 33).During a 3D forging, in microscler protrusion 246, form porose 244.Similarly, utilize the 2nd 3D forging process, the first protrusion 240 is extended to form microscler protrusion 248 and hole 250 (Figure 34).As become clearer below, microscler protrusion 246,248 will form fork leg (or the blade 224,226 in the embodiment of integral type steering tube-shoulder lid-blade 222).

When described two microscler protrusions 246,248 are formed, blank utilizes the 3rd 3D to forge step and processes to be formed the 3rd microscler protrusion 252 (Figure 35) with hole 254.3rd protrusion 252 extends along with microscler protrusion 246,248 substantially vertical directions from the end of blank 238.3rd protrusion 252 has the size and the length that form steering tube 140.Next, the method respectively the first protrusion 248 away from the part 254 of the 3rd protrusion 252 and the part 256 away from the 3rd protrusion 252 of the second protrusion 246 perform swaged forging operation (Figure 36).Swaged forging is utilize mould in part 254,256, to produce tapered portion with the cool working process making the end diameter of microscler protrusion 246,248 less than the diameter of the part adjacent with the 3rd protrusion 252.Should be understood that, at elongate section 246,248 by the embodiment of the blade in formation suspension fork, swaged forging operation can be saved.It is contemplated that can combine due to the 3D forging operation shown in Figure 32 to Figure 35, the parts therefore shown in Figure 35 are produced with single 3D forging operation by the blank shown in Figure 31.

In some embodiments, operation bidirectional as known in the art can be performed to obtain required blade plan form on the first protrusion 248 and the second protrusion 246.Such as, protrusion 246,248 " can dock " to form variable wall.Protrusion 246,248 can also be formed as having such as non-circular, incomparable inconsistent or variable shape along its length.

Once microscler protrusion 246,248 is by swaged forging, then bending operation is used to form shoulder lid 190 and blade/fork leg 258,260 (Figure 37).Finally, perform and such as machinework is carried out with the secondary operation of the welding, soldering, bonding, combination and so on of the final size or hook pawl 194 (Figure 38) that form steering tube 140 to the 3rd protrusion 252.Other secondary operations can also comprise such as the formation of other features in such as hole 232,234 and so on.

Turn to Figure 39 to Figure 50 now, forge another illustrative methods forming integral type steering tube-shoulder lid-fork 402 to utilizing multistage 3D and be described.Except single rigid leg or blade, integral type steering tube-shoulder lid-fork 402 covers with steering tube-shoulder-and blade 236 is similar.Integral type steering tube-shoulder lid-fork 402 defines being rigidly connected between wheel 110 and handlebar 145.

The method starts from blank 404 as shown in Figure 39, blank 404 by metal as aluminium---comprise such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.Blank is bent to the basic configuration 406 forming integral type steering tube-shoulder lid-fork 402 subsequently.Basic configuration 406 comprises Part I 408, first protrusion 410 and the second protrusion 412, and wherein, Part I 408 will form steering tube, and the first protrusion 410 will form leg or blade, and the second protrusion 412 will be used to form axle.When basic configuration 406 is formed, following step relates to the two-dimentional forging process of formation shape 414 as shown in Figure 41.Forging axle continues to use the direction insertion that arrow 416 represents.This two dimension forging makes the second microscler protrusion 412 have less diameter.

When the second protrusion 412 is extended, blank 404 stands the 3D forging process of formation axle 418, brake plate 420 and the shoulder lid 422 formed as shown in Figure 42.Axle direction arrow 416 represents.This 3D forging yet forms both hole 424 (Figure 45).Next, the method performs forks piece 426 shaped and is squeezed into the 2nd 3D forging process of Len req as shown in Figure 43.Net shape 428 is formed with the 3rd 3D forging process top section 408 being as shown in Figure 44 formed as steering tube 430 and hole 432 (Figure 45).It is contemplated that, because the 3D forging operation shown in Figure 41 to Figure 44 can be combined, therefore net shape 428 produces with the single 3D forging operation after two-dimentional forging process.

In some embodiments, expect as shown in Figure 46 to Figure 48, utilize blade insert 434 to come the end of blind hole 424.In the exemplary embodiment, blade insert 434 arranges and is bonded in hole 424.The end of blade insert 434 blind hole 424 and this end of axle 418 is stablized.Finally, can perform and such as the secondary operation of machinework and so on be carried out to form the final size of the final integral type steering tube-shoulder lid-fork 402 shown in Figure 49 to Figure 50 to steering tube 430.

Should be understood that, the 3D forging process discussed with reference to Figure 42 to Figure 44 can also be used to manufacture the integral type steering tube shown in Figure 51-shoulder lid-blade configuration.Present embodiment and the steering tube-shoulder of the integral type shown in Fig. 7 to Figure 10 cover-and blade 222 is roughly similar.In the present embodiment, comprise 3D and forge step to form wheel installation junction surface or hook pawl 194 and braking fabricated section 420 on the roughly two opposite sides of fork or blade 224,226.

To keep high strength at expendable weight and obtain the advantage of the number reducing parts while the material property of high tenacity on the miscellaneous part that above-mentioned 3D forging process can also be used in bicycle 100.Turn to Figure 52 to Figure 99 now, by the number of components to little weight, minimizing, high strength crank assemblies 170 and manufacture method be described.

Crank assemblies 170 comprises Part I 302, Part II 304, star gear 306, lock ring 308 and bolt 309, as shown in Figure 52.Part I 302 comprises integral type and all-in-one-piece arm-shaft component 310, integral type and all-in-one-piece arm-shaft component 310 by metallic material as aluminium---include but not limited to such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---formed.Part I 302 is by being formed the 3D forging process described in more detail below.One-piece member 310 comprises arm 312, and wherein, axle portion 314 extends from an end of arm 312.One-piece member 310 also comprises the feature at such as star gear junction surface 316 and Part II junction surface 318 and so on.Part I 302 can also comprise the pedal (not shown) being attached to one-piece member 310 by the opening 320 in arm 312.In another embodiment, star gear 306 can be formed as one by 3D forging operation the integral part of formula component 310.This also will save the machinework to star gear junction surface 316 and lock ring 308.But modular separable star gear 306 can provide advantage by allowing at various bicycle style (such as, road cycling, mountain bike etc.) upper use crank assemblies 170.

Part II 304 comprises arm 322, and arm 322 is similar with arm 312 on size and dimension.Boss 324 is extended with from an end of arm 322.Boss 324 comprises opening 326, and opening 326 has sizing and the feature of shaped one-tenth receiving Part II junction surface 318 and axle 314.The fastener 309 in order to Part I 302 to be attached to when crank assemblies 170 is mounted to bicycle 100 Part II 304 is extended with through opening 326 and axle 314.

Process for the formation of Part I 302 has been shown in Figure 52 to Figure 59.This process to start from by metallic material as aluminium---include but not limited to such as 6061-T6,7075-T6,7050-T73,2024,2014 or 6069 aluminum alloys---blank 328 (Figure 53) made.Blank stands the first forging process in Figure 54 to form substantially rectangular portion 330.First forging process can also form stage portion 331 in blank 328, thus forms the more minor diameter 333 as shown in Figure 61.More minor diameter 333 can also comprise fine taper portion section 335.In some embodiments, stage portion 331 provides the surface that star gear 306 is located against it.This tapered portion section can also form Part II junction surface 318 during secondary operation.

Blank 328 is processed to form arm 312 by a 3D forging operation subsequently, the solid part 334 that arm 312 has the axial hole 332 as shown in Figure 55 to Figure 56 and Figure 61 to Figure 65 and is positioned on an end.Formed arm 312 350 (Figure 67) angled relative to the axis 352 of axle 314.In one embodiment, arm 312 has the first curved wall 336 and the second curved wall 338.Curved wall 336,338 is connected with wall 342 by the 3rd wall 340 as shown in figure 65.Wall 336,338,340,342 defines axial hole 332.In an embodiment shown in Figure 66, curved wall 336,338 has the first thickness 344 and connecting wall 340,342 has the second thickness 346.In the exemplary embodiment, the first thickness 344 is the half of the second thickness 342.In one embodiment, the first thickness 344 is 2 millimeters and the second thickness 342 is 4 millimeters.

When arm 312 is formed, this process extends more minor diameter 331 to form the axle 314 as shown in Figure 57 to Figure 58 and Figure 67 to Figure 71 by the 2nd 3D forging subsequently.Axle 314 is formed with axial hole 348.Axial hole 348 is crossing with the axial hole 332 of arm 312.In one embodiment, axial hole 348 is formed as blind hole to extend through arm 312, as shown in Figure 67 to Figure 71 during the 2nd 3D forges step.In another embodiment, hole 348 is formed as the blind hole on the end 354 of axle 314 with opening, as shown in Figure 57 to Figure 58.In arbitrary embodiment, hole 348 is one after the other extended into through hole during secondary operation.In the exemplary embodiment, axle 314 has the external diameter of 30 millimeters.

After formation axle 314, this process performs bending operation subsequently on arm 312, as shown in Figure 59 and Figure 72 to Figure 76.In one embodiment, the angle of the part 356 of arm 312 is become substantially vertical with axis 352 from angled 350 directed changes by bending operation.It is directed that Part II 358 is held in angle 350.

Following step in this process is the end of closed axial hole 332.Should be understood that, the energy of arm 312 and axle 314 transmit cycling during each stroke person, thus cause larger load applying to the arm 312 of Part I 302 region crossing with axle 314.In order to strengthen and reinforce this intersection, in axial hole 332, be inserted with pin or connector 360 (Figure 77 to Figure 87).Connector 360 shaped becomes to meet the shape---such as arcuate surfaces 362---of axial hole 332 such as to match with curved wall 336,338.Connector 360 can also comprise hole 364, and hole 364 is sized to roughly the same with the size and dimension of axial hole 348.When connector 360 is inserted in axial hole 232, connector 360 is arranged so that hole 62 is coaxial with axial hole 348.Connector 360 is such as attached to Part I 302 by force fit, bonding or soldering.

In another embodiment, the end of axial hole 332 is closed instead of closes, as shown in Figure 88 to Figure 89 with connector 360 in forging process.In the present embodiment, wall 336 is formed with the protrusion 368 contrary with axle 314.Protrusion 368 can be formed during a 3D forging process in the 3D forging process such as such as shown in Figure 57 to Figure 58.In order to the end of closed axial hole 332, protrusion 368 make in the dislodgment of protrusion 368 to the forging in the opening 370 in axial hole 332 processed.This encloses opening 370 and on wall 336, obtain roughly level and smooth outside face as shown in Figure 89.

At connector 360 fastened or axial hole 332 is otherwise closed, this process is by carrying out secondary machine operations so that extension 366 through hole formed as shown in Figure 60 and Figure 81 to Figure 87 of star gear junction surface 316, Part II junction surface 318 and axial hole 348 is completed one-piece member 310 to axle 314.Opening 320 is formed in solid part 334 for installation pedal.

In another embodiment, the process similar with said process can be used perform the 3D carried out from the pedal end of arm as shown in Figure 90 to Figure 91 to forge.In the embodiment shown in Figure 90, arm 312 is formed with opening 370 with 3D forging, and opening 370 is positioned on the end contrary with axle 314 of arm 312.Arm 312 is formed the protrusion 372 adjacent with opening 370 carry out closing openings 370 to allow forging step and form solid part 334.Once form solid part 334, axle 314 is just formed by 3D forging as above.

In the embodiment shown in Figure 91, the mode that arm 312 forges with 3D is formed with opening 370, and opening 370 is positioned on the end contrary with axle 314 of arm 312.Arm 312 is formed the protrusion 372 adjacent with opening 370, and axle 314 forms protrusion 374 by 3D forging on the end contrary with arm 312 of axle 314.Protrusion 374 is shifted subsequently with the end 354 of closed axial hole 348 in forging operation.Finally, forge step make dislodgment with closing openings 370 and form solid part 334.

Part II 304 shown in Figure 92 to Figure 99 also can by being formed with a series of 3D forging processes roughly similar about the 3D forging process described by Part I 302.Blank is forged into and forms the rectangular portion similar with rectangular portion 334.The arm 322 with axial hole 376 forms axial hole 376 by 3D forging subsequently, and axial hole 376 is formed by a pair relative curved wall 378,380.Curved wall 378,380 connects a pair connecting wall 382,284.In one embodiment, curved wall 378,380 has thickness 386, and thickness 386 is the half of the thickness of connecting wall 382,384.In one embodiment, thickness 386 is 2 millimeters and thickness 388 is 4 millimeters.

With regard to the axle 314 of Part I 302, boss 324 extends subsequently in 3D forging operation.Opening 326 partly forges in step at 3D and is formed, and wherein, opening 326 is extended into through hole by secondary operation.When boss 324 is formed, arm 322 is bent to and makes Part I 390 substantially vertical with the axis 392 of opening 326.Part II 394 is held in angle 396 (Figure 98) relative to axis 392.Once arm 322 is bent, just perform secondary machine operations to be formed for the opening 398 of pedal (not shown) and form the feature 400 being attached to Part II junction surface 318 in opening 326.

Referring now to Figure 100 to Figure 101, show another crank assemblies 450, crank assemblies 450 utilizes the 3D forging process similar with above-mentioned 3D forging process to manufacture to form an integral and all-in-one-piece crank arm.In the present embodiment, crank arm 452 comprises the first arm 454 and the second arm 456.Boss portion 460 is extended with from the end contrary with the first arm of the second arm.First arm 454 is general planar and consistent along its length.Be formed with opening 458 in an end of the first arm 454, opening 458 is sized to receives pedal (not shown).Second arm 456 extends from the end of the first arm 454.In the exemplary embodiment, the second arm is angularly arranged relative to the first arm.Second arm is tapered, makes the second arm have first width approximate with the first arm and have the second width at opposite ends place.In the exemplary embodiment, the second width is greater than the first width.The tapered portion of the second arm provides the advantage of increase strength and stiffness to turn and to adapt to the transverse force on crank assemblies 450 during pushes pedals.

Enclosed cavity 462 is provided with in arm 452.In the exemplary embodiment, chamber 462 extends through to the second arm 456 from the first arm 454.Chamber 462 shaped becomes along the first arm wall thickness roughly consistent with the length restriction of the second arm.Therefore, the part 464 being positioned at the first arm 454 in chamber 462 has the width 466 of constant.But the part 468 in chamber 462 is expanded to the width 470 of opposite ends from the end adjacent with the first arm.Chamber 462 and arm 454,456 coordinate with the thickness of the length confining wall along chamber.Should be understood that, this thickness is consistent on the direction being approximately perpendicular to this wall.

By making chamber portion 468 along the length dilatation of the second arm, also reducing the amount of the material in crank assemblies 450 or making the amount of the material in crank assemblies 450 minimize to obtain advantage in expendable weight while opposing transverse force.By closing this chamber with end wall 467,469, have also obtained the further advantage in the balance of weight and intensity.Should be understood that, two ends in chamber 462 can be bent to or shaped becomes to adapt to forging processing or conducting forging processing.

In one embodiment, the first arm and the second arm have the first wall thickness 472 and in second direction 478, have the second wall thickness 476 on first direction 474.Direction 474 is vertical with direction 478.In the embodiment that the wall limited by chamber and arm is bending, the second wall thickness 476 can be determined by the line of centers in chamber.In one embodiment, the thickness of the thickness on first direction 474 between 1 millimeter and 1.5 millimeters and in second direction 478 is 2.5 millimeters to 4 millimeters.In the exemplary embodiment, direction 474 is parallel with the axis 480 in the hole 482 in boss portion 460 and direction 478 is vertical with axis 480.Axis 480 is also roughly parallel to the hole 458 in the second arm 454.In one embodiment, computerized numberical control (CNC) fine limit work is carried out to produce final crank shape and the edge that limits of the outside face giving this crank and aesthetic impact and allow further to control wall thickness to the outside face of crank.

Referring now to Figure 102, show and there is integration and another crank assemblies 484 of the axle 486 of integral type.Similar with the embodiment shown in Figure 100 to Figure 101, crank assemblies 484 comprises the crank arm 452 with the first arm 454 and the second arm 456.The width of the first arm 454 is roughly consistent along its length.Second arm 456 angularly to extend and from second width of the tapered Cheng Geng great of the width roughly the same with the first arm from the first arm.Chamber 462 extends to the second arm from the first arm 454.Chamber 462 coordinates the roughly consistent wall thickness of the length kept along chamber 462 with the first arm 454 and the second arm 456.In one embodiment, this chamber and crank arm 452 define the first wall of the first thickness had on first direction and define the second wall of the second thickness had in second direction, as above with reference to Figure 101 discuss.

In the present embodiment, axle 486 utilizes as formed above with reference to the three-dimensional forging process described by Figure 53 to Figure 91 herein.First boss portion 460 is formed in the end of Part II 456.3D forging process is used to make dislodgment and form axle 486 here.The subsequent operation of such as machine operations can be used to form hole 488.Axle 486 such as can comprise a large amount of features, such as but not limited to star gear junction surface 316 and junction surface 318 (Figure 60).

Of the present invention as illustrated by each accompanying drawing and appended text and the embodiment described provides a kind of bicycle of one or more feature had in following characteristics: integral type and all-in-one-piece steering tube and shoulder cover; Integral type and all-in-one-piece steering tube, shoulder lid and front vane; The all-in-one-piece crank arm of integral type and axle; By the hollow crank arm that 3D forging is formed; And be there is steering tube, shoulder lid and the integral type of blade and the fork assembly of integral type that are formed by 3D forging.One or more advantage during these features can have the following advantages compared to existing technology: the part and assembly of intensity lower, higher in weight, larger toughness, lower productive costs, faster assembling and lesser number.

According to an embodiment of the invention, provide a kind of following bicycle: this bicycle has wheel, head tube and is operatively attached to described integral type fork of taking turns.Fork comprises the steering tube being operatively attached to head tube, and wherein, this steering tube comprises first hole with first axle.Be extended with shoulder lid from an end of steering tube continuously, wherein, pitch the metallic material forged by three-dimensional (3D) and make.In one embodiment, shoulder lid comprise first protrusion with the first opening, this first opening has the second axis, wherein, this second axis and first axle almost parallel.Shoulder lid can also comprise second protrusion with the second opening, this second opening has the 3rd axis, wherein, the 3rd axis and first axle almost parallel.In another embodiment, shoulder lid is also included in the second hole extended between the first opening and the first hole.In yet, shoulder lid also comprises the 3rd hole, and the 3rd hole extends through the end of the first protrusion from the first opening, wherein, the 3rd hole is coaxial with the first hole.In an embodiment again, the first hole is closed covering on adjacent end with shoulder.In yet, the first opening is closed covering on adjacent end with shoulder.In yet, fork also comprises the first protrusion extended continuously from shoulder lid, and is extended with the first blade from the first protrusion continuously along the direction roughly contrary with steering tube.In an embodiment again, fork also comprises and covers from shoulder the second protrusion extended continuously, and is extended with the second blade continuously from the second protrusion, wherein, this second blade and the first blade almost parallel.In yet, this bicycle also comprise the first hook pawl and second hook pawl, wherein, this first hook pawl be attached to the first blade with shoulder cover contrary end, this second hook pawl be attached to the second blade with take on cover contrary end.

A kind of method manufacturing integral bike fork is embodiment there is provided according to another.The method is included on blank and performs the first forging to form the first protrusion.Blank performs a 3D forging to extend the first protrusion thus to form shoulder lid.Blank performs the 2nd 3D forging to form steering tube, wherein, the second protrusion is substantially vertical with the first protrusion.The first end of the first protrusion by swaged forging to form blade.First protrusion is bent along the direction contrary with the second protrusion.First protrusion is bonded to the first hook pawl.Be to form the 3rd protrusion when blank performing the first forging.Blank performs the 3rd 3D forging to extend the 3rd protrusion after the step of prolongation first protrusion.First protrusion is bent along the direction contrary with the second protrusion.Make the first protrusion bending after, the 3rd protrusion is bent along the direction contrary with the second protrusion.First protrusion is bonded to the first hook pawl and the second protrusion is bonded to the second hook pawl.The first end of the first protrusion by swaged forging with form blade and the second end of the 3rd protrusion also by swaged forging.In the first protrusion, be formed with opening, wherein, this opening and the second protrusion almost parallel.The first hole is formed between the second hole in the first opening and the second protrusion.Between the first opening and the end of the first protrusion, be formed with the 3rd hole, wherein, the 3rd hole is roughly coaxial with the first hole.In one embodiment, the first protrusion comprises first axial hole with the closed end adjacent with the second protrusion and the second protrusion comprises second axial hole with the closed end adjacent with the first protrusion.

A kind of following integral bike fork is embodiment there is provided: this integral bike fork has forges by carrying out a 3D to metal stock the shoulder lid formed to form the first protrusion according to another.Be extended with steering tube from shoulder lid, this steering tube is formed by the 2nd 3D forging, has the first axial hole in this steering tube.Shoulder lid also comprise the first opening, this first opening and the first axial hole almost parallel.The second hole is provided with between the first hole and the first opening.Between the end that the first opening and shoulder cover, be provided with the 3rd hole, wherein, the 3rd hole is roughly coaxial with described second hole.Be extended with the first blade from shoulder lid, this first blade is formed by the Part I of the first protrusion, and wherein, this Part I is by swaged forging and bend to the direction contrary with steering tube, edge subsequently and extend, and the first opening axially extends in the first blade.First opening can also comprise the closed end adjacent with steering tube.First hole can also comprise covers adjacent closed end with shoulder.The second blade is extended with from shoulder lid, wherein, this shoulder covers and is formed by the first protrusion and the second protrusion during a 3D forging, and this second blade is formed by the Part II of the second protrusion, wherein, this Part II is bent to subsequently along the direction contrary with steering tube extend by swaged forging.The cover contrary end be connected with the first hook pawl with shoulder of first blade, and the covering contrary end and be connected with the second hook pawl with takeing on of the second blade.

A kind of crank assemblies for bicycle with the Part I of integral type is embodiment there is provided according to another.Part I comprises first arm with the first solid end and the first axial hole, and this first axial hole extends to the second end from first end.Part I also comprises the axle being adjacent to the second end generally perpendicularly extend from this arm, and this axle has the second axial hole being adjacent to the second end extend in the first arm, and this second axial hole is arranged to crossing with the first axial hole.Be provided with the Part II with the second arm, this second arm has the 3rd solid end and the 3rd axial hole, and the 3rd axial hole extends to the 4th end from the 3rd end, and this Part II and the 4th end are adjacent to operatively be attached to described axle.First arm can comprise the first bending wall and bending second wall relative with the first wall, and wherein, axle extends from the second wall.Between the first wall with the second wall, be provided with the 3rd wall and between the first wall and the second wall, be provided with the wall relative with the 3rd wall.Wherein, the first wall, the second wall, the 3rd wall and wall define the first axial hole.In one embodiment, the first wall and the second wall have the first thickness and the 3rd wall and wall have the second thickness.In another embodiment, the first thickness is the roughly half of described second thickness.In another embodiment, the first thickness is 2 millimeters and the second thickness is 4 millimeters.Crank assemblies can also comprise the connector being adjacent to be attached in the first axial hole the first arm with the second end.In one embodiment, crank assemblies can also comprise the first protrusion being adjacent to the second end extend from the first wall, and wherein, this first protrusion is forged into closes described first axial hole at the second end place.

A kind of method manufacturing integral bike crank-arm and axle is embodiment there is provided according to another.The method comprises by the first microscler arm of 3D forging formation, and this first arm has solid first end and the first axial hole, and this axial hole has the first opening at the second end place contrary with first end of the first arm.First arm is formed first protrusion adjacent with the second end.By forging prolongation first protrusion by 3D and forming the second axial hole and form axle in the first protrusion.First brachiocylloosis becomes to make solid end substantially vertical with the first protrusion.Form the second microscler arm by 3D forging, this second arm has solid 3rd end and the 3rd axial hole, and the 3rd axial hole has the second opening in the 4th end of the second arm.The second microscler arm is formed second protrusion adjacent with the 3rd end.In the second protrusion, be formed with four-axial hole, wherein, this four-axial hole is sized to relatively receives axle with the first arm.Insert the first connector in the first opening and insert the second connector in the second opening.First connector and the second connector are attached to the first arm and the second arm by force fit, soldering or bonding.

This written description uses example openly to comprise the present invention of best mode, and makes any those skilled in the art to implement the present invention, comprises the method manufacturing and use any device or system and perform any merging.The scope of the obtainable patent of the present invention is limited by claim, and can comprise other examples that those skilled in the art expect.If these other examples have the structural constituent as broad as long with the literal word of claim, if or these other examples comprise and having and the equivalent structural elements of the literal word of claim without essential difference, then these other examples are intended to belong in the scope of claim.In addition, in the accompanying drawings and the description, disclose illustrative embodiments of the present invention, although and may particular term be have employed, but unless otherwise stated, otherwise these particular term are still only for general and descriptive meaning but not for the object of restriction, therefore, scope of the present invention is not limited thereto.In addition, term first, second, forward and backward, top, the end, upper and lower etc. use do not represent any orientation, order or importance, term first, second etc. be used to an element to separate with another element region.In addition, term one, a kind of etc. use do not represent number quantitative limitation, but represent to exist with reference at least one in item with reference to item.

Claims

1., for a crank assemblies for bicycle, described crank assemblies comprises:

Integrated integral type body, comprising:

First arm;

Second arm, described second arm angularly extends from one end of described first arm;

The chamber closed, described closed chamber is arranged between described first arm and described second arm, the first end place of described chamber in described first arm has the first width and has the second width in the end of described second arm, described chamber and described first arm limit the first wall thickness in a first direction, described chamber and described second arm limit the second wall thickness in a second direction, described first wall thickness and described second wall thickness roughly equal; And

Boss portion, described boss portion extends from the end contrary with described first arm of described second arm.

2. crank assemblies according to claim 1, wherein, described first thickness and described second thickness are roughly consistent along described first arm with the length of described second arm.

3. crank assemblies according to claim 2, wherein, described chamber and described first arm limit the 3rd wall thickness on third direction, and described third direction is substantially vertical with described first direction.

4. crank assemblies according to claim 3, wherein, described chamber and described second arm limit the 4th wall thickness in fourth direction, and described fourth direction is substantially vertical with described second direction.

5. crank assemblies according to claim 4, wherein, described 3rd wall thickness and described 4th wall thickness roughly equal.

6. crank assemblies according to claim 5, wherein, described 3rd wall thickness and described 4th wall thickness are roughly consistent along described first arm with the described length of described second arm.

7. crank assemblies according to claim 6, wherein:

Described first wall thickness and described second wall thickness are between 1 millimeter and 1.5 millimeters; And

Described 3rd wall thickness and described 4th wall thickness are between 2.5 millimeters and 4 millimeters.

8. crank assemblies according to claim 1, also comprises and shape all-in-one-piece axle portion one-body molded with described boss portion.

9. crank assemblies according to claim 8, wherein, described first arm comprises the first hole extending through described first arm, and described first hole is positioned between the end of described chamber and described first arm.

10. crank assemblies according to claim 9, wherein, described axle portion comprises the second hole extending through described axle portion, and described second hole is positioned between the end of described chamber and described boss portion.

11. 1 kinds of crank assemblies for bicycle, described crank assemblies comprises:

First arm, described first arm has the first width;

Second arm, described second arm extends from described first arm and has first end and the second end, and wherein, described first end has the second width, described the second end has the 3rd width, described 3rd width than described second width and described first width large;

The chamber closed, described closed chamber extends to described second arm from described first arm, described chamber coordinates to limit the first wall thickness with described first arm and described second arm, and described first wall thickness is roughly consistent along described first arm with the length of described second arm; And

Boss portion, described boss portion extends from described the second end.

12. crank assemblies according to claim 11, wherein, described second width and described first width roughly equal.

13. crank assemblies according to claim 12, wherein, described chamber and described first arm and described second arm coordinate to limit the second wall thickness on the direction substantially vertical with described first wall thickness.

14. crank assemblies according to claim 13, wherein, described second wall thickness is greater than described first wall thickness.

15. crank assemblies according to claim 14, wherein, described second wall thickness is roughly consistent along described first arm with the described length of described second arm.

16. crank assemblies according to claim 15, also comprise and shape all-in-one-piece axle portion one-body molded with described boss portion.

17. crank assemblies according to claim 16, wherein, described first arm is general planar and described second arm angularly extends from described first arm.

18. crank assemblies according to claim 17, wherein, described first arm is arranged in the plane substantially vertical with the axis in described axle portion.

19. crank assemblies according to claim 18, wherein, described first arm comprises the first maintaining part, and described first maintaining part is arranged between described chamber and the 3rd end, and described 3rd end is contrary with described first end.

20. crank assemblies according to claim 18, wherein:

Described first wall thickness is between 1 millimeter and 1.5 millimeters; And

Described second wall thickness is between 2.5 millimeters and 4 millimeters.