CN100395051C - Method for reinforcing spoke structural strength of bicycle and motor vehicle - Google Patents

Abstract

The present invention provides a method for strengthening the spoke structure intensity of a bicycle and a car. Primarily, the structure intensity of a spoke at the elbow part is enhanced by a mechanical processing way; especially, the metal intensity of a spoke at the elbow part is enhanced (shearing stress is enhanced) by a multiple punch forming way by means of the metal processing hardened principle; simultaneously, the linear diameter is increased (the sectional area is increased) because of squeezing action. Shearload is equal to shearing stress multiplied by sectional area. After the processing, practical tests all obtain the conclusion that the tension intensity of the spoke reaches the tension intensity of metal raw materials by using the design of minimum materials, low processing cost and maximum strength.

Description

Strengthen the method for bicycle, locomotive spoke structural strength

Technical field

The invention relates to a kind of technology of strengthening the spoke structural strength.Especially relate to a kind of processing method that can strengthen the spoke overall construction intensity, it mainly is intensity of shear and the sectional area that improves spoke neck, bending part, and then overcomes the phenomenon of spoke in this position shearing loading deficiency.

Background technology

To so far, those skilled in the art person for the wheel hub of bicycle or locomotive wheel and spoke in the design of combined structure, considerable kind and kenel are provided, as TaiWan, China patent announcement No. 261953, No. 317821, No. 385284, No. 398423, No. 4485851, No. 516517, No. 511588 etc., though above-mentioned these patents can make this spoke provide utilization benefit more easily in assembling or dismounting, do not consider that spoke may cause fracture because of the deficiency of structural strength.

Most spokes is that the employing metal wire rod is a raw material, as carbon steel, stainless steel, titanium alloy etc., selected wire rod has better elastic and tension intensity mostly, but because of the intensity of shear of metal approximately has only half of tension intensity, Here it is, and spoke can be at first in the neck major cause of failure.In the stressed pull test of emulation spoke, also obtain identical result: the spoke neck is cut off (as shown in Figure 1, wherein B point for bearing the shearing maximum).

For a wheel, as long as a spoke fracture, all the other spokes also can rupture successively because of unbalance stress, and harm rider's safety.

For improving this shortcoming, the past industry also once had at the spoke structural design does considerable trial, mainly is that increasing line footpath (or local line footpath) is main.Though it is feasible directly to strengthen the line footpath, too waste material is violated the light-weighted trend of bicycle again, so that the adopter is few.As for adopting directly increasing person's (as D.B. two-part, SWAGE diameter reduced) of local line, also be to use big line footpath, dwindle the partial line footpath through grinding or forging again, processing cost is high, and the lightweight achievement is limited, has only the high unit price car type of minority to select for use.In other words, low cost, lightweight and high strength three seemingly can't take into account.

Summary of the invention

Main purpose of the present invention is to provide a kind of method of strengthening bicycle, locomotive spoke structural strength, it is a principle of utilizing metal work hardening, adopt repeatedly stamping forming mode, local density and the intensity that improves metal grain, promote the shear stress of material with this, and the line footpath is increased because of squeezing action.

Shearing loading (Kgf)=shear stress (Kgf/mm ²) ↑ sectional area (mm ²) ↑

When the tension intensity of the shearing loading 〉=wire rod of spoke, the intensity of spoke can reach maximum (equaling the tension intensity of wire rod).

Be that the spoke main body is vertically broken (normal stress), but not neck is cut off.The objective of the invention is to realize by following technical proposals, reinforcement bicycle of the present invention, the method of locomotive spoke structural strength, mainly state the structural strength that adopts the machining mode to promote this spoke bending part, it is to utilize repeatedly stamping forming technical approach to make the neck of spoke and bending part improve intensity because of metal work hardening effect, and thereby increase the sectional area of neck and bending part, and in being actually used in the raw material tensile test after this processing, can obtain the spoke structure of the highest effect of the minimum intensity of the metal material that uses, so to reach purpose and the effect of strengthening the spoke structural strength.Be preferably, wherein employed spoke material means carbon steel, stainless steel and titanium alloy steel.Being preferably the punch forming number of times that wherein applies to the spoke bending part is to depend on that actual required shearing resistance and stretching resistance is foundation.

The present invention is according to manufacture method that above-mentioned purpose is used and make advantage on the article function, will be described in detail according to the preferred embodiment shown in the following drawings, makes it it is had more to be well understood to.

Description of drawings

Fig. 1 is the fracture schematic diagram that spoke is commonly used in expression;

Fig. 2 is the spoke structural representation that expression mat the inventive method is made;

Fig. 3 is the shearing of the inventive method enforcement and the curve map that the punching press number of times changes;

Fig. 4 is that expression the inventive method makes spoke structure shaping schematic view gradually.

The element numbers simple declaration

Spoke (1)

Bending part (2)

Neck (3)

Head (4)

The specific embodiment

The present invention provides a kind of method of strengthening bicycle, locomotive spoke structural strength, and this method system adopts the machining mode to promote the structural strength of the neck 3 and the bending part 2 of this spoke 1 body; The explanation of making comparisons of general spoke and the spoke after the inventive method processing below is described respectively:

With the material be stainless steel SS 304 to utilize the made spoke body of known techniques 1 be example, the about 60kgf/mm of its shear stress ², the about 110kgf/mm of pulling force ², therefore, if the line of spoke directly is 2.0mm, then:

1. the spoke maximum pull that can bear is

110kgf/mm ²·[(2.0/2) ²·π]mm ²＝345kgf

2. the spoke maximum shear that can bear is (actual spoke is non-perpendicular to be cut off, and section approximates 4.5 ~ 5.0)

60kgf/mm ²·[4.5~5.0]mm ²＝270~300kgf

By the aforementioned calculation result as can be known, though the pulling force of this spoke can reach more than the 340kg, in fact, this spoke can produce fracture when 280kg.

Above-mentioned spoke body 1 is forged aftershaping through three punching presses, the neck 3 lines footpath that can make this spoke body 1 is strengthened and naturally in bending part 2 places formation thickened section, as shown in Figure 2, the former line footpath φ B (φ 2.0) of this spoke body 1 will become the size of φ A (φ 2.3), and its ratio increases by 1.15 approximately; And after this processing, can promote the pulling force and the shear value at this position simultaneously; Thus, just can under the principle that increases material hardly, promote the structural strength of spoke.

Be again further confirm method of the present invention may with and the tool value, the spy will test through the spoke after this processing, former spoke is in three punching courses, the line of its spoke directly changes as shown in Figure 3, its result then as shown in Figure 4; The last achievement of this spoke of dying is as follows: actual shearing loading promotes

(267-190)/190＝40.5％

Actual cross-section is long-pending to be promoted

$\frac{\mathrm{\π}[{\left(2.26\right)}^2-{\left(1.98\right)}^2]/4}{\mathrm{\π}{\left(1.98\right)}^2/4}=30.3\%$

Actual shear stress promotes

(66.6-61.3)/61.3＝8.65％

Final finished is done tensile test, the disrumpent feelings spoke main body that is in, and tension intensity is 345kgf.(elbow is intact)

More than the conclusion as can be known, the spoke that produces with traditional methods after the inventive method, can obtain the spoke structure of the highest effect of the minimum intensity of the metal material that used, and can effectively reach purpose and the effect of strengthening the spoke structural strength.

Because it is the repeatedly stamping forming practice in the machining mode that the present invention adopts, so can make the privileged site of spoke 1 such as bending part 2, neck 3 etc. under the consumption that does not change its use material, increase its line footpath thickness naturally, and when increasing the line footpath, the pulling force and the shearing that can make this bending part 2, neck 3 can bear again improve, not only be different from and commonly use simple increase material usage (promptly selecting the thicker steel in line footpath for use), the more perfection that kills two birds with one stone of inventor's clever thought utilization design.

In sum, the method for reinforcement bicycle provided by the present invention, locomotive spoke structural strength really is one to be applied to promote novelty, the practical approach of spoke intensity, and really can promotes significantly.

The above only for the present invention one preferable feasible embodiment, so use the equivalence variation that specification of the present invention and claim are done such as, ought to be included in the claim of the present invention.

Claims (3)

1. method of strengthening bicycle, locomotive spoke structural strength, it mainly is to adopt the machining mode to promote the structural strength of this spoke bending part, it is characterized in that: utilize at least three stamping forming technical approach to form the neck and the bending part of spoke, make that the neck line of this spoke directly is 1.15 times of the former line of spoke footpath, and in bending part place formation thickened section, so to reach purpose and the effect of strengthening the spoke structural strength.

2. according to the method for the described reinforcement bicycle of claim 1, locomotive spoke structural strength, wherein employed spoke material means carbon steel, stainless steel and titanium alloy steel.

3. according to the method for the described reinforcement bicycle of claim 1, locomotive spoke structural strength, the punch forming number of times that wherein applies to the spoke bending part is to depend on that actual required shearing resistance and stretching resistance is foundation.

Images