BICYCLE SEAT RAIL MANUFACTURING METHOD

Abstract

A bicycle seat rail manufacturing method includes the steps of: pre-annealing, providing an aluminum alloy workpiece having undergone pre-annealing; first-stage heat treatment, performing heat treatment of full annealing on the aluminum alloy workpiece by a bending shaping, calendaring the aluminum alloy workpiece by a calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by a cold forging shaping to increase its cross-sectional area; second-stage heat treatment, enhancing hardness of the aluminum alloy workpiece by a quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by a tempering shaping; and cryogenic treatment, performing high-speed bombardments on the surface of the aluminum alloy workpiece by a shot blasting shaping to enhance its durability and service life. Therefore, a bicycle seat rail integrally formed of aluminum alloy is manufactured by the aforesaid steps.

Description

FIELD OF THE DISCLOSURE

The present disclosure relates to bicycle technology, and more particularly to a method of manufacturing seat rail integrally formed of aluminum alloy.

BACKGROUND OF THE DISCLOSURE

A conventional bicycle typically includes a saddle and a seat rail adapted to support the saddle and fixedly coupled to a seatpost of the bicycle. The seat rail is fixedly disposed on the anterior bottom surface of the saddle and includes two parallel rails extended backward and inserted finally into two fixing holes on the posterior bottom surface of the saddle, respectively, allowing the seat rail to be integrally coupled to the saddle.

Conventionally, a seat rail is an important weight-bearing part of a bicycle. The seat rail of a moving bicycle not only bears the rider's weight but is also affected by different vibration frequencies and road jerks. As a result, seat rails are required to demonstrate high mechanical strength and impact resistance. However, when manufactured by bending a metal rod, a conventional seat rail lacks adequate overall structural strength to the detriment of the stability of the connection between the saddle and the seatpost. Furthermore, seat rails made of metal are heavy. Although seat rails made of lightweight, high-strength carbon fiber are commercially available and in wide use, they are brittle and thus pose safety risks.

Owing to the increasing demand for lighter bicycles, related manufacturers aim to develop lighter saddles. However, manufacturing seat rails from metal or carbon fiber workpieces obviously goes against the trend toward lightness of saddles.

Therefore, it is imperative to provide a lightweight seat rail made of aluminum alloy and characterized by high structural strength.

SUMMARY OF THE DISCLOSURE

It is an objective of the disclosure to provide a bicycle seat rail manufacturing method for performing heat treatment on an aluminum alloy workpiece to produce a seat rail integrally formed of aluminum alloy and characterized by lightness and high structural strength.

To achieve the above and other objectives, the disclosure provides a bicycle seat rail manufacturing method, comprising the steps of: pre-annealing, providing an aluminum alloy workpiece and performing heat treatment of pre-annealing; first-stage heat treatment, performing heat treatment of full annealing on the aluminum alloy workpiece by bending shaping, heating the aluminum alloy workpiece again by calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by cold forging shaping so as for the aluminum alloy workpiece to take on a larger cross section; second-stage heat treatment, enhancing hardness of the aluminum alloy workpiece by quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by tempering shaping; and cryogenic treatment, performing high-speed bombardments on a surface of the aluminum alloy workpiece by shot blasting shaping to enhance durability and service life of the aluminum alloy workpiece. Therefore, the aforesaid steps are effective in manufacturing a bicycle seat rail integrally formed from an aluminum alloy workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a manufacturing method in the first embodiment of the disclosure.

FIG. 2 is a flowchart of first-stage heat treatment in the first embodiment of the disclosure.

FIG. 3 is a flowchart of second-stage heat treatment in the first embodiment of the disclosure.

FIG. 4 is a flowchart of cryogenic treatment in the first embodiment of the disclosure.

FIG. 5 is a perspective view of an aluminum alloy workpiece of the disclosure.

FIG. 6 is a perspective view of the aluminum alloy workpiece that has undergone heat treatment according to the disclosure.

FIG. 7 is another perspective view of the aluminum alloy workpiece that has undergone heat treatment according to the disclosure.

FIG. 8 is a perspective view of a seat rail of the disclosure.

FIG. 9 is a flowchart of first-stage heat treatment in the second embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Referring to FIG. 1 through FIG. 9, FIG. 1 through FIG. 8 illustrate a bicycle seat rail manufacturing method in the first embodiment of the disclosure and its steps as follows:

Step S1: pre-annealing, providing an aluminum alloy workpiece 1, performing heat treatment of pre-annealing on the aluminum alloy workpiece 1, and severing the aluminum alloy workpiece 1 by an appropriate length. In this embodiment, the heat treatment of pre-annealing entails heating up the aluminum alloy workpiece 1 to a specific temperature higher than a recrystallization temperature and then leaving the aluminum alloy workpiece 1 alone for a cold forging time period during which its temperature drops gradually.

Step S2: first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping. The aluminum alloy workpiece 1 has developed internal stress by the time step S1 is done, If the internal stress is excessive but is not timely eliminated, the aluminum alloy workpiece 1 will deform and even develop cracks in it. To cope with this issue, heat treatment of full annealing is performed on the aluminum alloy workpiece 1 by the bending shaping. In this embodiment, the heat treatment of full annealing involves heating up the aluminum alloy workpiece 1 gradually at 350° C.˜400° C. After that, the aluminum alloy workpiece 1 is calendered by the calendering shaping and then left alone for a cooling time period. In this embodiment, the cooling time period is 5-15 minutes. Finally, the aluminum alloy workpiece 1 is bombarded in multiple instances with a cold forging tool by the cold forging shaping, allowing the aluminum alloy workpiece 1 to take on a larger cross section.

Step S3: second-stage heat treatment, having a quenching shaping and a tempering shaping. By the time step S2 is done, the hardness and structural strength of the aluminum alloy workpiece 1 has been attenuated. Thus, the quenching shaping entails cooling quickly the aluminum alloy workpiece 1 in mineral-containing water, oil or air immediately after the aluminum alloy workpiece 1 has been heated up to a specific temperature, so as to enhance the hardness of the aluminum alloy workpiece 1 and thereby enable the aluminum alloy workpiece 1 to attain required mechanical properties. The tempering shaping entails heating up the aluminum alloy workpiece 1 again to a temperature lower than the lower critical temperature, then keeping the aluminum alloy workpiece 1 at the temperature for a time period, and finally cooling down the aluminum alloy workpiece 1 in a medium, such as air, water or oil, gradually, so as to enhance the internal structure stability of the aluminum alloy workpiece 1 and thereby prevent the aluminum alloy workpiece 1 from undergoing structural transitions in the course of usage.

Step S4: cryogenic treatment, having a shot blasting shaping. After the aluminum alloy workpiece 1 has undergone steps S1˜S3, its surface has to be modified to improve its superficial mechanical properties, such as wear resistance, high-temperature resistance, and corrosion resistance. Thus, the shot blasting shaping entails performing high-speed bombardments on the surface of the aluminum alloy workpiece 1 with numerous fine particles to form tiny impressions or dents on the surface of the aluminum alloy workpiece 1 and thereby enhance the durability and service life of the aluminum alloy workpiece 1.

Therefore, the aluminum alloy workpiece 1 undergoes steps S1˜S4 to produce a seat rail 2 integrally formed of aluminum alloy. The essential technical features of steps S1˜S4 are described below. The first-stage heat treatment involves bending the aluminum alloy workpiece 1 by the bending shaping technique to form a bent segment 10, then calendering the aluminum alloy workpiece 1 by the calendering shaping technique to form a support segment 11 connected to the bent segment 10, an extension segment 12 connected to the support segment 11 and a rear segment 13 connected to the extension segment 12. However, in this embodiment, the order of the bending shaping preceding the calendering shaping is subject to changes as needed. For example, it is feasible to carry out the calendering shaping by calendaring the aluminum alloy workpiece 1 to form a support segment 11, an extension segment 12 connected to the support segment 11 and a rear segment 13 connected to the extension segment 12 and then carry out the bending shaping by bending the aluminum alloy workpiece 1 to form a bent segment 10 connected to the support segment 11.

The seat rail 2 integrally formed of aluminum alloy according to the disclosure comes in two different feasible structures. Regarding the first structure, the bent segment 10, support segment 11, extension segment 12 and rear segment 13 of the seat rail 2 each have a non-round cross section in the radial direction (as shown in FIG. 6). Regarding the second structure, the bent segment 10, support segment 11 and rear segment 13 of the seat rail 2 each have a round cross section in the radial direction, but the extension segment 12 of the seat rail 2 has a non-round cross section in the radial direction (as shown in FIG. 7). The bent segment 10 of the seat rail 2 is insertedly disposed on the bottom surface of a saddle 3 (as shown in FIG. 8).

Referring to FIG. 1, FIG. 3 through FIG. 9, a bicycle seat rail manufacturing method in the second embodiment of the disclosure comprises the steps as follows:

Step S1: pre-annealing, providing an aluminum alloy workpiece 1, performing heat treatment of pre-annealing on the aluminum alloy workpiece 1, and severing the aluminum alloy workpiece 1 by an appropriate length. In this embodiment, the heat treatment of pre-annealing entails heating up the aluminum alloy workpiece 1 to a specific temperature higher than a recrystallization temperature and then leaving the aluminum alloy workpiece 1 alone for a cold forging time period during which its temperature drops gradually.

Step S2: first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping. The aluminum alloy workpiece 1 has developed internal stress by the time step S1 is done, If the internal stress is excessive but is not timely eliminated, the aluminum alloy workpiece 1 will deform and even develop cracks in it. Thus, a high-frequency electromagnetic wave process is performed on the aluminum alloy workpiece 1 by the bending shaping. In this embodiment, the high-frequency electromagnetic wave process entails applying high-frequency electromagnetic wave with high frequencies of 400-500 Hz to the aluminum alloy workpiece 1 to cause vigorous collisions of the molecules of the aluminum alloy workpiece 1 and the resultant generation of heat with high temperature until the internal stress of the aluminum alloy workpiece 1 is eliminated and soften the aluminum alloy workpiece 1 to the extent required for thermal processing. The aluminum alloy workpiece 1 undergoes heat treatment by calendering shaping and then is left alone for a cooling time period. In this embodiment, the cooling time period is 5-15 minutes. Finally, the aluminum alloy workpiece 1 is bombarded in multiple instances with a cold forging tool by the cold forging shaping, allowing the aluminum alloy workpiece 1 to take on a larger cross section.

Step S3: second-stage heat treatment, having a quenching shaping and a tempering shaping. By the time step S2 is done, the hardness and structural strength of the aluminum alloy workpiece 1 has been attenuated. Thus, the quenching shaping entails cooling quickly the aluminum alloy workpiece 1 in mineral-containing water, oil or air immediately after the aluminum alloy workpiece 1 has been heated up to a specific temperature, so as to enhance the hardness of the aluminum alloy workpiece 1 and thereby enable the aluminum alloy workpiece 1 to attain required mechanical properties. The tempering shaping entails heating up the aluminum alloy workpiece 1 again to a temperature lower than the lower critical temperature, then keeping the aluminum alloy workpiece 1 at the temperature for a time period, and finally cooling down the aluminum alloy workpiece 1 in a medium, such as air, water or oil, gradually, so as to enhance the internal structure stability of the aluminum alloy workpiece 1 and thereby prevent the aluminum alloy workpiece 1 from undergoing structural transitions in the course of usage.

Step S4: cryogenic treatment, having a shot blasting shaping. After the aluminum alloy workpiece 1 has undergone steps S1˜S3, its surface has to be modified to improve its superficial mechanical properties, such as wear resistance, high-temperature resistance, and corrosion resistance. Thus, the shot blasting shaping entails performing high-speed bombardments on the surface of the aluminum alloy workpiece 1 with numerous fine particles to form tiny impressions or dents on the surface of the aluminum alloy workpiece 1 and thereby enhance the durability and service life of the aluminum alloy workpiece 1.

Therefore, the aluminum alloy workpiece 1 undergoes steps S1˜S4 to produce the seat rail 2 integrally formed of aluminum alloy. The essential technical features of steps S1˜S4 are described below. The first-stage heat treatment involves bending the aluminum alloy workpiece 1 by the bending shaping technique to form a bent segment 10, then calendering the aluminum alloy workpiece 1 by the calendering shaping technique to form a support segment 11 connected to the bent segment 10, an extension segment 12 connected to the support segment 11, and a rear segment 13 connected to the extension segment 12. However, in this embodiment, the order of the bending shaping preceding the calendering shaping is subject to changes as needed. For example, it is feasible to carry out the calendering shaping by calendaring the aluminum alloy workpiece 1 to form a support segment 11, an extension segment 12 connected to the support segment 11, and a rear segment 13 connected to the extension segment 12 and then carry out the bending shaping by bending the aluminum alloy workpiece 1 to form a bent segment 10 connected to the support segment 11.

The seat rail 2 integrally formed of aluminum alloy according to the disclosure comes in two different feasible structures. Regarding the first structure, the bent segment 10, support segment 11, extension segment 12 and rear segment 13 of the seat rail 2 each have a non-round cross section in the radial direction (as shown in FIG. 6). Regarding the second structure, the bent segment 10, support segment 11 and rear segment 13 of the seat rail 2 each have a round cross section in the radial direction, but the extension segment 12 of the seat rail 2 has a non-round cross section in the radial direction (as shown in FIG. 7). The bent segment 10 of the seat rail 2 is insertedly disposed on the bottom surface of the saddle 3 (as shown in FIG. 8).

In conclusion, the seat rail 2, integrally formed of aluminum alloy by performing a heat treatment process on the aluminum alloy workpiece 1 in steps S1˜S4 of the manufacturing method according to the first and second embodiments of the disclosure, advantageously demonstrates high structural strength and lightness. Furthermore, the seat rail 2 integrally formed of aluminum alloy comprises segments that differ in curvature, namely the bent segment 10, support segment 11, extension segment 12 and rear segment 13, so as for the seat rail 2 to be ergonomic, shock-absorbing and durable.

Claims

1. A bicycle seat rail manufacturing method, comprising the steps of: pre-annealing, providing an aluminum alloy workpiece and performing heat treatment of pre-annealing;first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping, applying a full annealing temperature to the aluminum alloy workpiece by the bending shaping, heating the aluminum alloy workpiece again by the calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by the cold forging shaping so as for the aluminum alloy workpiece to take on a larger cross section;second-stage heat treatment, having a quenching shaping and a tempering shaping, enhancing hardness of the aluminum alloy workpiece by the quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by the tempering shaping; andcryogenic treatment, having a shot blasting shaping, performing high-speed bombardments on a surface of the aluminum alloy workpiece by the shot blasting shaping to enhance durability and service life of the aluminum alloy workpiece.

2. The bicycle seat rail manufacturing method of claim 1, wherein the full annealing temperature is 350° C.˜400° C., and the cooling time period is 5-15 minutes.

3. The bicycle seat rail manufacturing method of claim 2, wherein the full annealing temperature is preferably 380° C.˜390° C., and the cooling time period is preferably 10 minutes.

4. The bicycle seat rail manufacturing method of claim 1, wherein an integrally formed seat rail is manufactured by the pre-annealing, the first-stage heat treatment, the second-stage heat treatment and the cryogenic treatment, and the seat rail has a bent segment, a support segment connected to the bent segment, an extension segment connected to the support segment, and a rear segment connected to the extension segment.

5. The bicycle seat rail manufacturing method of claim 4, wherein the bent segment, the extension segment and the rear segment each have a round cross section in a radial direction, and the support segment has a non-round cross section in a radial direction.

6. A bicycle seat rail manufacturing method, comprising the steps of: pre-annealing, providing an aluminum alloy workpiece and performing heat treatment of pre-annealing;first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping, applying high-frequency electromagnetic wave with high frequencies of 400-500 Hz to the aluminum alloy workpiece by the bending shaping, heating the aluminum alloy workpiece again by the calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by the cold forging shaping so as for the aluminum alloy workpiece to take on a larger cross section;second-stage heat treatment, having a quenching shaping and a tempering shaping, enhancing hardness of the aluminum alloy workpiece by the quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by the tempering shaping; andcryogenic treatment, having a shot blasting shaping, performing high-speed bombardments on a surface of the aluminum alloy workpiece by the shot blasting shaping to enhance durability and service life of the aluminum alloy workpiece.

7. The bicycle seat rail manufacturing method of claim 6, wherein an integrally formed seat rail is manufactured by the pre-annealing, the first-stage heat treatment, the second-stage heat treatment and the cryogenic treatment, and the seat rail has a bent segment, a support segment connected to the bent segment, an extension segment connected to the support segment, and a rear segment connected to the extension segment.

8. The bicycle seat rail manufacturing method of claim 7, wherein the bent segment, the extension segment and the rear segment each have a round cross section in a radial direction, and the support segment has a non-round cross section in a radial direction.