Method for Making a Bicycle Hub

Abstract

A method of making a rear hub of a bicycle comprises: swaging a straight pipe into an hour-glass-shaped semi product, extruding the semi-product to form a hub flange, punching a plurality of holes in the hub flange of the semi-product, binding an edge of an end of the semi-product, necking down the edge-bound end of the semi-product, trimming the semi-product, and chamfering the holes of the semi-product to form a chamfer structure on an edge of the respective holes.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of making a component of a bicycle, and more particularly to a method of making the rear hubs of a bicycle.

2. Description of the Prior Art

Hub is an important component disposed in the center of a wheel of a bicycle, and the hub is generally in the form of a hollow pipe that is formed at either end thereof with a circular hub flange, and in the hub flange are annularly formed a plurality of through holes for insertion of spokes.

U.S. Pat. No. 4,998,344 discloses a method for manufacturing a hub, which comprises the following steps: rotary swaging a work piece to form a semi-product, the work piece is simultaneously struck by three or more dies from the outer peripheral side so that the semi-product is formed smoothly and homogeneously, and two bearing cup seats are simultaneously formed on both ends of the semi-product; and squeezing both ends of the semi-product by a right mold and a left mold so as to form a hub. However, this method of manufacturing a hub still has the following shortcomings that need to be improved:

Firstly, the length of the resultant hub usually exceeds the maximum tolerance because of the factors of the molding tolerance and the length tolerance of the work piece.

Secondly, during the swaging process, the radial dimension of the hub often deviates from the preset value. If the hole of the hub is too large, then the axle cannot be firmly positioned in the hub, and if the hole of the hub is too small, it will be difficult to assemble the axle into the hub.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a method of making a rear hub of a bicycle, and the method comprises the steps of swaging, extruding, punching, edge binding, necking and trimming and chamfering. Through the above steps, the rear hub can be made more compact and the strength of the rear hub can be strengthened.

A method for making a rear hub of a bicycle in accordance with the present invention comprises the following steps:

swaging a straight pipe into an hour-glass-shaped semi product;

extruding the semi-product to, form a hub flange at either end of the semi-product;

punching a plurality of holes in the hub flange of the semi-product, and the holes are annularly arranged;

binding an edge of an end of the semi-product;

necking down the edge-bound end of the semi-product,

trimming both ends of the semi-product to a predetermined value; and

chamfering the holes of the semi-product to form a chamfer structure on an edge of the respective holes.

The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart in accordance with the present invention of showing the steps of making the rear hub of a bicycle;

FIG. 2 is an illustrative view of showing a straight pipe;

FIG. 3 shows that the straight pipe has been swaged into a semi-product;

FIG. 4 shows the semi-product after it is extruded,

FIG. 5 shows the semi-product after it is punched;

FIG. 6 shows the semi-product after it is trimmed;

FIG. 7 shows the semi-product after its edge has been bound;

FIG. 8 shows the semi-product after its end has been necked down; and

FIG. 9 shows the resultant product after being chamfered.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-9, a method of manufacturing a rear hub of a bicycle in accordance with the present invention is shown and comprises the following steps:

A, swaging: placing a straight pipe 21 (work piece) into a mold and swaging it into an hour-glass-shaped semi product 22, as shown in FIG. 10.

B, Extruding: extruding the semi-product 22 to form a hub flange 23 at either end of the semi-product 22, as shown in FIG. 11.

C, Punching: punching a plurality of holes 24 in the hub flange 23 of the semi-product 22, as shown in FIG. 12, wherein the holes 24 are annularly arranged;

D, binding: binding the edge of an end of the semi-product 22 to make the size of the end of the semi-product 22 satisfy the requirement.

E, necking down the edge-bound end of the semi-product 22 to the predetermined value, as shown in FIG. 13, for facilitating assembly of axial tube, bearing, ball race and etc.

F, Trimming: trimming both ends of the semi-product 22 to the predetermined value.

G, Chamfering; chamfering the holes 24 of the semi-product 22 to form a chamfer structure 25 on the edge of the holes 24, as shown in FIG. 16, for quick and easy assembly of the spokes.

Edge binding process not only can make the size of the edge of the end of the semi-product 22 more compact and precise, but also can improve the semi-product's strength.

It will be noted that the steps of necking, trimming and chamfering can be performed in any order according to need, for example: the chamfering process can be carried out first, then the necking process and then the trimming process. Or, trimming process can be made before the necking and chamfering processes.

While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.

Claims

1. A method for making a rear hub of a bicycle comprising the following steps: swaging a straight pipe into an hour-glass-shaped semi product; extruding the semi-product to form a hub flange at either end of the semi-product; punching a plurality of holes in the hub flange of the semi-product, and the holes are annularly arranged; binding an edge of an end of the semi-product; necking down the edge-bound end of the semi-product; trimming both ends of the semi-product to a predetermined value; and chamfering the holes of the semi-product to form a chamfer structure on an edge of the respective holes.

2. The method for making a rear hub of a bicycle as claimed in claim 1, wherein the chamfering step is allowed to be carried out before the step of necking down the edge-bound end of the semi-product.

3. The method for making a rear hub of a bicycle as claimed in claim 1, wherein the trimming step is allowed to be carried out before the step of necking down the edge-bound end of the semi-product.

4. The method for making a rear hub of a bicycle as claimed in claim 1, wherein the chamfering step is allowed to be carried out before the trimming step.

5. The method for making a rear hub of a bicycle as claimed in claim 1, wherein the steps of necking, trimming, chamfering and edge-binding are allowed to be carried out in any order.