TW201800163A - Manufacturing method for bicycle cassette and mold set used for the same capable of achieving bidirectional forging effect and reducing manufacturing time - Google Patents

Abstract

A mold set includes a first mold and a second mold. The first mold has a non-circular first cavity recessed into the first mold to a certain depth. The second mold has a second cavity recessed into the second mold to a certain depth and a plurality of grooves on the wall surrounding the second cavity of the second mold; and a plurality of flash portions formed at the bottom of the second mold and each of the flash portions is connected to the corresponding groove. A manufacturing method for bicycle cassette is performed sequentially by the following steps: material preparation, bidirectional forging, heat treatment, fine cutting, and surface treatment. The material preparation step is to prepare a blank and a mold set described above. The blank is placed into the mold set, such that the blank is forged into a semi-finished product of a cassette to complete the bidirectional forging step. The heat treatment step is performed on the semi-finished product withdrawn from the mold set for hardness enhancement. The flashes can be removed after performing the fine cutting step to obtain the cassette fitted with the standard dimensions. Then, the surface treatment step is performed to obtain the finished product of cassette. Thus, the invention can achieve bidirectional forging effect to reduce the manufacturing time for bicycle cassette.

Description

Tower base manufacturing method and mold set used by the method

The invention relates to the manufacturing technology of a bicycle, in particular to a method for manufacturing a tower base and a mold set used by the method.

A bicycle usually has a frame. Two front and rear wheels are installed on the frame. Each hub of the front or rear wheel is assembled with a hub (also known as a hub or hub). The hub is connected to a tower base (also called a cassette or Cassette). The two are sleeved together on a shaft, and the shaft is mounted on the frame by a quick release (or Quick Release), which supports the rear wheel to rotate relative to the frame, making it convenient for the bicycle to travel on the road.

The base is connected to a flywheel (also known as Freewheel), and the flywheel is connected to a large gear assembly (also known as Chainwheel) as a transmission system through a chain (also called Chain), which converts the kinetic energy of human body pedaling into the potential energy of bicycle movement .

The molding method disclosed in Taiwan Patent Publication No. 201518005 makes a semi-finished product of a tower base.

Figure 9 shows the complete manufacturing process of the traditional tower foundation, except that the steps of material preparation 10 → one-way forging 11 → milling groove 13 → heat treatment 14 → fine cutting 16 → surface treatment 18 are sequentially performed.

In the stock preparation step, blanks and mold sets are usually prepared. The blank is usually a solid round rod made of aluminum, an aluminum alloy, or one of titanium and a titanium alloy.

The mold set has a first mold and a second mold. As shown in FIG. 10, the first mold 40 has a first cavity 42, which is plunged into the first mold 40 to a certain depth. Wherein, the first mode The cavity 42 is round in shape.

In FIG. 11, the second mold 50 has a second cavity 52 and a plurality of grooves 54. The second cavity 52 is plunged into the second mold 50 to a certain depth, and includes a large-diameter section 51 and a small-diameter section 53. The diameter of the large-diameter section 51 is substantially equal to the diameter of the first cavity 42, and is closer to the opening of the second cavity 52 than the small-diameter section 53. These grooves 54 are formed on the wall surface of the second mold 50 surrounding the small diameter section 53. In addition, a hollow convex post 58 extends from the bottom of the second cavity 52 toward the opening direction, and stands in the center of the small-diameter section 53.

In the one-way forging step, the blank is placed in a die set, so that the blank is forged into a semi-finished product of a tower base. In Figure 12, the profile of the semi-finished product conforms to the volume shape where the first and second mold cavities 42, 52 are combined. The semi-finished product has a first blind hole 28 and a second blind hole 21. The first blind hole 28 is formed at a part of the semi-finished product corresponding to the convex pillar 58. The second blind hole 21 and the first blind hole 28 are located at different positions of the semi-finished product. In the end, the two are not connected to each other. The semi-finished product also has a plurality of keys 22 that surround the first blind hole 28 and form a key slot 24 between two adjacent keys 22. Because the semi-finished product is larger than the dotted line to indicate the standard value of the size of the base 30, the two ends of the semi-finished product have a flash 32, 34, respectively.

In the trench milling step, a cutting operation is performed on the semi-finished product exiting the mold group, which not only removes excess flash material, but also forms the required receiving groove 26, as shown in FIG. 13. The receiving groove 26 and the key 22 are at different ends of the semi-finished product.

In the heat treatment step, a semi-finished product that conforms to the standard size of the base 30 is subjected to a heat treatment operation with an increased hardness, so that the semi-finished product is not affected by the excessive influence of thermal expansion and contraction.

In the fine cutting step: except that the first and second blind holes 28 and 21 are penetrated to form a single shaft hole 23, the precise size is obtained through the turning operation, and the almost completed tower base 30 is obtained.

The final surface treatment step is only to perform the final treatment on the surface of the base 30.

However, the traditional method of making tower bases has the following disadvantages:

First of all, there is a lot of spillage and a lot of waste, not only wasting materials, but also the high cost, which is not conducive to market competition.

Second, the one-way forged bond of the tower base. The accommodating groove at the other end of the tower base is to remove the required groove and then use a milling cutter to cut the required groove, so there is an additional production process, which relatively prolongs the processing time.

In addition, the removal of flash material requires equipment, manpower, and time, which increases unnecessary processing costs.

Therefore, how to improve the manufacturing process of the tower base has become an urgent problem to be solved by the present invention.

In view of this, the main purpose of the tower foundation manufacturing method provided by the present invention is to adopt a two-way forging method to reduce the manufacturing process of the tower foundation, relatively reduce the manufacturing cost, and improve the competitiveness of the market.

The main purpose of the die set provided by the present invention is to achieve the effect of two-way forging and reduce the time required for tower base manufacturing.

The mold set of the present invention includes: a first mold including: a first mold cavity which is plunged into the first mold to a certain depth; the shape of the first mold cavity is non-circular; a second mold including: : A second cavity, which is plunged into the second mold to a certain depth; a plurality of grooves in the second mold surrounding the wall surface of the second cavity; a plurality of flashover portions, which are formed in the depth direction At the bottom of the second cavity, each overflow portion is connected to a corresponding groove.

When two molds are combined, the first and second mold cavities can forge a blank into a tower. Base semi-finished products. Except for the overflow part, the sum of the depth of the two cavities is approximately equal to one of the metric and inch specifications of the base length.

The second cavity is selected from one of the following shapes and is implemented on the first mold: first, a number of shaped blocks, each of which is raised on the wall of the first mold surrounding the first cavity; second, the first The wall surface of the mold surrounding the first cavity is one of a polygonal shape, a polygonal shape, and a gear shape.

Of course, the first mold also has a raised portion, which protrudes from the center of the bottom of the first cavity.

Specifically, the second cavity further includes a large diameter section and a small diameter section. The large-diameter section is closer to the opening of the second cavity than the small-diameter section, and the groove is formed on the wall surface of the second mold surrounding the small-diameter section. The second mold also has a convex post, which is hollow and extends from the bottom of the second mold cavity toward the opening direction and stands in the center of the small diameter section.

Therefore, when the mold set of the present invention is placed in the second cavity of the first blank, the first and second molds are merged to forge the blank into a semi-finished product of a tower base, except that part of the blank is formed by the overflow portion to form an overflow. In addition, the two ends of the semi-finished product are shaped by the first and second mold cavities to form the required shape of the tower foundation, and the length of the semi-finished product is approximately equal to the sum of the depths of the two mold cavities, which is consistent with the standard size of the tower foundation.

The invention provides a tower foundation manufacturing method, which sequentially performs the following steps: a material preparation step: preparing a blank material, which is a solid bar of aluminum alloy No. 7xxx series; as in any of the scope of application for patents Nos. 1 to 6 A die set according to one item; a two-way forging step: the blank is placed in the die set, so that the blank is forged into a semi-finished product of a tower base, the contour of the semi-finished product conforms to the volume shape of the first and second cavity combinations, At the positions corresponding to the special-shaped block, the groove and the flashing part, a receiving groove, a key and a flashing material are respectively formed in accordance with the shape; Heat treatment step: perform semi-finished products withdrawn from the mold group to perform heat treatment operations with increased hardness; fine cutting step: semi-finished products that have undergone heat treatment are removed by cutting tools to obtain a tower base that meets the standard size; and surface treatment steps: Surface treatment operations.

The aluminum alloy serial number of the blank can be one of No. 7005, No. 7072, No. 7075, No. 7116, No. 7129, or No. 7178.

It is assumed that in the two-way forging step, the convex pillars in the die set can form a first blind hole in the blank. The raised portion of the mold group can form a second blind hole in the blank. In the fine cutting step, a drilling operation is performed on the semi-finished product after heat treatment to make the first and second blind holes communicate.

In this way, the tower base manufacturing method of the present invention has the following advantages over the traditional manufacturing method:

First, there is no trench milling step, so the tower foundation manufacturing process of the present invention is shorter than the traditional manufacturing method.

2. The two-way forging step of the present invention combines the effectiveness of the two steps of "one-way forging" and "groove milling" of the traditional manufacturing method, so that the required contour or functional shape of the tower foundation can be put in place at once, and unnecessary waste is avoided.

Third, effective spill control, waste is naturally less than the traditional method, not only save materials, but also reduce costs, and relatively improve the competitiveness of the market.

4. Simultaneously forge the keys and accommodating grooves required for the tower foundation, eliminating the need to use a milling cutter to cut the groove in the traditional manufacturing method, and effectively reduce man-hours.

Fifth, there is less flash, the time required for "fine cutting" is of course shorter than the traditional method, and the processing cost is relatively reduced.

Next, the related embodiments will be described in detail based on the drawings, and the technology and means adopted will be described. And effects, it is believed that the above-mentioned object, structure and characteristics of the present invention should be understood deeply and concretely.

10‧‧‧ preparation

11‧‧‧One-way forging

12‧‧‧Two-way forging

13‧‧‧Mill groove

14‧‧‧ heat treatment

16‧‧‧Fine cutting

18‧‧‧ surface treatment

20‧‧‧ embryo

21‧‧‧second blind hole

22‧‧‧ key

23‧‧‧shaft hole

24‧‧‧slot

26‧‧‧Receiving trough

28‧‧‧ the first blind hole

30‧‧‧ Taki

32, 34‧‧‧ Overfill

40‧‧‧The first mold

42‧‧‧The first mold cavity

44‧‧‧wall

46‧‧‧shaped block

48‧‧‧ bulge

50‧‧‧Second Mould

51‧‧‧large diameter section

52‧‧‧Second mold cavity

53‧‧‧Small diameter section

54‧‧‧Groove

56‧‧‧Overflow Department

58‧‧‧ convex post

FIG. 1 is a flowchart of a tower base manufacturing method and a mold set used in the method of the present invention.

Figures 2 to 4 are schematic diagrams of the materials and mold sets required for the material preparation step.

Figures 5 and 6 are comparison charts before and after cutting the semi-finished product of the tower base.

Figures 7 and 8 are reference views for implementing other first molds.

Fig. 9 is a flowchart of a conventional tower-based manufacturing method.

Figures 10 and 11 are schematic diagrams of molds used in the traditional tower foundation manufacturing method.

Figures 12 and 13 are comparison diagrams before and after cutting the traditional semi-finished product of the tower base.

As shown in FIG. 1, the method for preparing the base of the present invention is illustrated, and steps are sequentially performed: preparation of material 10 → bidirectional forging 12 → heat treatment 14 → fine cutting 16 → surface treatment 18 and the like.

In the material preparation step, a blank 20 and a mold set as shown in FIG. 2 are prepared. The blank 20 is selected from a series of aluminum alloys No. 7xxx made of solid bars for use. Because aluminum alloys contain different proportions of materials, and different numbers of aluminum alloys have different metal characteristics, they have a great impact on the metal characteristics of the blank 20, and even if the tower base is manufactured according to the following steps, it may produce different effects. Therefore, it is recommended to choose one of the aluminum alloys, such as 7005, 7072, 7075, 7116, 7129, or 7178, which is a better reference.

In addition, in order to ensure the metal characteristics of the billet 20, meet the standard specifications of the base, or shorten the time required for manufacturing, the hardness of the billet 20 must be increased according to processes such as heating → cooling → annealing.

During heating, the blank 20 is heated according to a range of rising temperature of 340 ° C to 440 ° C, and the insulation is periodically maintained according to the ratio of weight to time. The weight to time ratio is about 1 (Tons): 5 (hours).

During cooling, the temperature is reduced to a range of about 210 ° C to 310 ° C, so that the heated blank 20 is cooled and maintained for a certain period of time. Specifically, the cooling time is about 6 to 9 hours.

During annealing, the aforementioned cooled blank 20 is cooled to a normal temperature state, and it has a certain Rockwell hardness, such as HRC45 ~ 55. The normal temperature here, also called normal temperature or room temperature, is usually defined as 25 ° C (about 77 ° F or 300K thermodynamic temperature).

In FIGS. 3 and 4, the mold set includes a first mold 40 and a second mold 50.

The first mold 40 has a first mold cavity 42 which sinks into the first mold 40 to a certain depth. In this embodiment, the shape of the first cavity 42 is non-circular. A plurality of irregularly shaped blocks 46 are raised around the wall 44 of the first cavity 40 in the first mold 40, and the irregularly shaped blocks 46 are separated from each other by a certain distance or angle. In addition, the first mold 40 also has a raised portion 48 protruding from the center of the bottom of the first cavity 42.

In some embodiments, the wall surface of the first mold 40 surrounding the first cavity 42 is gear-shaped, as shown in FIG. 7. In some embodiments, the wall surface of the first mold 40 surrounding the first cavity 42 may be a polygon (or a hexagon), as shown in FIG. 8.

In FIG. 4, the second mold 50 has a second cavity 52, a plurality of grooves 54, a plurality of overflow portions 56, and a convex post 58. Wherein, the second cavity 52 is plunged into the second mold 50 to a certain depth. Specifically, the second cavity 52 includes a large-diameter section 51 and a small-diameter section 53. The large-diameter section 51 is closer to the opening of the second cavity 52 than the small-diameter section 53. These grooves 54 surround the wall surface of the second mold cavity 52 in the second mold 50, and each groove 54 is formed in the wall surface of the second mold 50 surrounding the small diameter section 53. These flash portions 56 are formed at the bottom of the second cavity 52 in the depth direction, and each flash portion 56 is connected to a corresponding groove 54. The protruding post 58 is hollow, and extends from the bottom of the second cavity 52 toward the opening direction and stands on Small diameter section 53 center.

In the two-way forging step, the blank is put into a die set, so that the blank is forged into a semi-finished product of the base 30, as shown in FIG. 5. The contour of the semi-finished product conforms to the volumetric shape of the first and second mold cavities, and a corresponding accommodating groove 26 and a second blind hole 21 are respectively formed at corresponding positions of the shaped block and the raised portion. Of course, the semi-finished product corresponding to the groove, the flash portion and the protruding column will also form a key 22, a flash 32, 34, and a first blind hole 28 corresponding to the shape. The semi-finished product of the tower base 30 forms a plurality of key grooves 24, and each key groove 24 separates two adjacent keys 22.

In the heat treatment step, the semi-finished product withdrawn from the mold group is subjected to a heat treatment operation with an increased hardness, so that the effect of thermal expansion and contraction on the size of the semi-finished product of the base 30 is minimized.

Fine cutting step: The semi-finished product after heat treatment is removed by the cutting tool to obtain a base 30 conforming to the standard size, as shown in FIG. 6. At the same time, a drilling operation is performed on the heat-treated semi-finished product so that the first and second blind holes communicate with each other to form a separate shaft hole 23.

Finally, the base 30 is subjected to a surface treatment operation to complete the surface treatment steps to obtain a finished product.

In this way, the tower base manufacturing method of the present invention has the following advantages over the traditional manufacturing method:

First, there is no trench milling step, so the tower foundation manufacturing process of the present invention is shorter than the traditional manufacturing method.

2. The two-way forging step of the present invention combines the effectiveness of the two steps of "one-way forging" and "groove milling" of the traditional manufacturing method, so that the required contour or functional shape of the tower foundation can be put in place at once, and unnecessary waste is avoided.

Third, effective spill control, waste is naturally less than the traditional method, not only save materials, but also reduce costs, and relatively improve the competitiveness of the market.

4. Simultaneously forge the keys and accommodating grooves required for the tower foundation, eliminating the need to use a milling cutter to cut the groove in the traditional manufacturing method, and effectively reduce man-hours.

Fifth, there is less flash, the time required for "fine cutting" is of course shorter than the traditional method, and the processing cost is relatively reduced.

Therefore, when the mold set of the present invention is placed in the second cavity, the first and second dies are merged together to forge the blank into a semi-finished product of a tower base, except that part of the blank is formed by the overflow part to form an overflow. The two ends of the semi-finished product are shaped by the first and second mold cavities to form the required shape of the tower foundation, and the length of the semi-finished product is approximately equal to the sum of the depth of the two mold cavities, which is consistent with the standard size of the tower foundation.

10‧‧‧ preparation

12‧‧‧Two-way forging

14‧‧‧ heat treatment

16‧‧‧Fine cutting

18‧‧‧ surface treatment

Claims (9)

A mold set includes: a first mold (40) including: a first mold cavity (42) that is plunged into the first mold (40); the shape of the first mold cavity (42) is non-circular; a second The mold (50) includes: a second cavity (52), which is plunged into the second mold (50); a plurality of grooves (54), the grooves (54) surrounding the second mold (50) The wall surface of the cavity (52); a plurality of overflow portions (56) are formed in the depth direction at the bottom of the second cavity (52), and each overflow portion (56) is connected to a corresponding recess Groove (54); when a blank (20) is placed in the second cavity (42, 52), the first and second molds (40, 50) are merged to forge the blank (20) into a tower base ( 30) semi-finished product, except that part of the blank (20) is formed by the overflow portion (56) to form the flash (34), the two ends of the semi-finished product are formed by the first and second mold cavities (42, 52) to form the base (30) ) Required shape, and limit the length of the semi-finished product is approximately equal to the sum of the depth of the two mold cavities (42, 52), and is consistent with the standard size of the base (30). The mold set according to item 1 of the scope of patent application, wherein the first mold (40) further has a plurality of shaped blocks (46), and each of the shaped blocks (46) protrudes from the first mold (40) and surrounds the first mold (40). The wall surface (44) of the cavity (42). The mold set according to item 1 of the patent application scope, wherein the wall surface (44) surrounding the first mold cavity (42) of the first mold (40) is one of a polygonal shape, a polygonal shape and a gear shape. The mold set according to item 1 of the patent application scope, wherein the first mold (40) further has a raised portion (48) protruding from the center of the bottom of the first cavity (42). The mold set according to item 1 of the scope of patent application, wherein the second cavity (52) further includes a large diameter section (51) and a small diameter section (53), and the large diameter section (51) is smaller than The diameter section (53) is close to the opening of the second cavity (52), and the groove (54) is formed on the wall surface of the second mold (50) surrounding the small diameter section (53). The mold set according to item 5 of the scope of patent application, wherein the second mold (50) further has a protruding column (58), the protruding column (58) is hollow and extends from the bottom of the second cavity (52). Open up It extends in the direction and stands in the center of the small diameter section (53). A tower foundation manufacturing method, which sequentially performs the following steps: preparing material (10): preparing a blank (20), which is a solid bar of aluminum alloy; as in any one of the first to sixth scope of the patent application Said die set; bidirectional forging (12) step: the blank (20) is put into the die set, so that the blank (20) is forged into a semi-finished product of a tower base (30), and the contour of the semi-finished product conforms to the first and the second The volume shapes of the two mold cavities (42, 52) are combined, and a corresponding receiving groove (26) is formed in the corresponding shape block (46), groove (54) and overflow part (56). One-click (22) and one flash (34); heat treatment (14) step: perform semi-finished products withdrawn from the mold group, perform heat treatment operations with increased hardness; fine cutting (16) step: the semi-finished products after heat treatment are removed by cutting tools Material (34) to obtain a base (30) conforming to the standard size; and a surface treatment (18) step: performing a surface treatment operation on the base (30). As described in the patent application scope item No. 7, the aluminum alloy serial number of the blank (20) may be No. 7005, No. 7072, No. 7075, No. 7116, No. 7129, or No. No. 7178. According to the tower base manufacturing method described in item 7 of the scope of patent application, in the two-way forging (12) step, the mold set, such as the convex pillar (58) described in the scope of patent application area 6, can form a blank in the blank (20). The first blind hole (28), such as the raised portion (48) described in item 4 of the patent application scope, can form a second blind hole (21) in the blank (20); in the step of fine cutting (16) In the process, a drilling operation is performed on the semi-finished product after the heat treatment to make the first and second blind holes (28, 21) communicate.