JPS61273221A - Hydraulic bulge forming of hanger lug - Google Patents

Abstract

PURPOSE:To form a hanger lug having plural bulge projections by bringing a base material steel tube to a hydraulic bulge forming by using a hydraulic fluid for a general purpose press machine and a pressure medium. CONSTITUTION:An oil tank is fixed onto a bed of a one-way reciprocating operation type general purpose press machine, and a base 8 is fixed to the bottom of the oil tank. Subsequently, a three-split type metallic die 4 engraved and provided a recessed and engraved part on the inside surface, and a metallic die supporting body 9 in an elastic body 11 are installed. In this state, a base material steel tube 2 is charged into the metallic die 4, and air in a steel tube 2 is replaced with a hydraulic fluid 17. Next, an upper punch 6 which is provided projectingly on a ram 5 of the press machine is made to descend and the upper end of the base material steel tube 2 is sealed up tightly and pressed, and a lower punch 12 seals up tightly the lower end of the base material steel tube 2, also receives a pressure, and compresses the base material steel tube 2. In this case, the pressure of the hydraulic fluid ascends, and a tube wall of the base material steel tube 2 bulges and projects to the recessed and engraved part of the metallic die 4. Also, a punch 7 which is provided projectingly on the ram 5 presses a plunger 13 of a pump 14 simultaneously, and even if the hydraulic fluid 17 in the base material tube 2 leaks, the hydraulic fluid is replenished continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a general-purpose press machine to produce hangers and lugs for bicycles using a hydraulic bulge forming method, without using rubber.
Concerning how to make rugs.

Generally speaking, the mainstream method for manufacturing non-ngar lugs in the bicycle industry is to charge high-quality, high-priced special synthetic rubber into a steel pipe and use this rubber as a pressure medium. It is. The general-purpose press machine used in this case is of the unidirectional reciprocating type and has a capacity of approximately 100 tons, and its equipment cost is much lower than that of a large hydraulic bulge machine.

The present invention utilizes a press machine with low equipment costs.

This project attempts to mold a hanger lug with a plurality of bulging protrusions from a raw steel pipe by a bulge forming method using hydraulic oil as a pressure medium instead of using high-quality synthetic rubber as a pressure medium.

The durability of the high-quality, high-priced special synthetic rubber used in the so-called "rubber bulge method" is that it can withstand approximately 400 to 500 continuous uses, after which it requires repair and maintenance and does not last long. It is.

If hydraulic oil is used instead of such rubber, it can be used permanently as a pressure medium without requiring any maintenance other than the natural wear and tear of the oil.

The method of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1 shows the bicycle hanger lug 1, which shows where it is located on the bicycle.It is a part that supports the bicycle's drive pedal (not shown), and generally there are other parts in the hanger lug. a plurality of bulge openings for engagement with the eleventh
The figure shows the completed hanger/rug product 1, where 1d is the lower pipe.

1c engages with the vertical pipes, and both la and 1b engage with the chain stay.

Fig. 2 shows a steel pipe 2 which is the starting material of the present invention, and an example of the material is STK, a steel pipe for mechanical structures specified by JIS.
MIIA and its size.

Length 95mm, outer diameter 38mm, wall thickness 31TIITI
belongs to.

However, it may be other than this. Fig. 3 shows the appearance of a raw material pipe 3 obtained by applying the hydraulic bulge forming method according to the present invention using the raw steel pipe 2 as a raw material, and shows bulging protrusions 3a, 3bt 3c.
, 3d indicate products whose heads are not opened or pierced. The size of the product after bulging C is approximately 75 mm in length, 38.5 m in outer diameter, and 3.2 mm in wall thickness, but the size of the bulging protrusion is not necessarily clear, nor is it clear.

The fourth drawing is a sketch of a three-part mold 4 for molding hangers and rugs in general as well as for the present invention.

As shown in the figure, it consists of three parts 4a + 4b + 4c, and four indentations are carved on the inner surfaces of these parts, but the intaglios will be omitted. FIG. 5 is a top view of the assembled mold 4 of the three parts 4a + 4b*4c, and the raw steel pipe 2 is charged into the central circular cavity shown in FIG. What should be noted here is the external shape of the mold 4, which is an inverted truncated cone with a smaller bottom.This is because the internal structure of the mold support 9, which will be described later, is shaped like a truncated cone with a larger bottom. The mold 4 is supported by the mold support 9 in cooperation with each other.

FIG. 6 shows a cross section of the main part of the present invention. To give an example, the oil tank 20 is fixedly mounted on the bed of a one-way reciprocating general-purpose press machine with a capacity of about 100 tons.

Although the size of the oil tank 20 is not specified in particular, the base 8 is installed on the bottom of the oil tank 20, the mold 4 and the mold support 9 are installed on it, the pump 14 is placed on the oil tank base 8, and the entire oil tank is installed. Fill with hydraulic oil 17.

It is assumed that all the instruments in the oil tank 20 are below the oil level of the hydraulic oil 17, but the upper end of the plunger 13 of the pump 14 may be above the oil level.

The base 8 has a hydraulic oil conduit 18 which passes through the lower punch and is installed at one end of the base 8, and this conduit 18 also communicates with the pump 14, the reason for their existence will be explained later.

The mold 4 is supported by the mold support 9, and as described above, the outer shape of the mold 4 is an inverted truncated cone, and the support 9 is the opposite truncated cone.

The mold 4 and the support body 9 are firmly and tightly fitted and held together. Furthermore, the support body 9 is an integral body formed by boring a hole in the center of a metal cylinder.

It is not divided like mold 4. The lower part of the support 9 is in contact with the base 8 via an elastic rubber 11, and is fixed to the base 8 by a bolt 10 that passes through the support 9 and the rubber 11, and this bolt 10 is inserted as shown in FIG. In this case, three are installed.

The reason why the supporting body 9 is attached to the base 8 via the rubber elastic body is that the raw steel pipe 2 installed in the mold 4 is pressed downward by the punch 6, and as a result, the hydraulic oil 1 As the hydraulic pressure of the mold 17 increases and the raw steel pipe 2 is compressed and deformed, the supporting body 9 is also deformed due to the elasticity of the rubber as the mold 4 changes.

Above the oil tank 20, there are an upper punch 6 that protrudes from the ram 5 of the press and a puncher that presses the plunger 13 of the pump 14.

Hydraulic oil 17 is injected into the oil tank 20 at an appropriate oil level, so when the raw steel pipe 2 is inserted and sectioned into the mold 4, the oil 17 also enters the steel pipe 2, and the inside of the pipe is The tube 2 is supported by the lower punch 12.

As shown in the figure, the lower punch 12 is fixed to the base 8 by tightening bolts.

The ram 5 of the press descends as the machine operates.

The upper punch 6 protruding from the ram 5 also descends at the same time.

While contacting and sealing the upper end surface of the tube 2, the lower punch 12 also seals the lower end surface of the raw material tube 2.

A punch 7 protruding from the ram 5 also presses the plunger 13 of the pump 14 at the same time as the upper punch 6. The pump 14 is equipped with a spring 15 therein, and works to always return the plunger 13, so that even if the hydraulic oil 17 in the material tube 2 leaks, the hydraulic oil 17 is constantly replenished. It's meant to work, and that's what it was set up for. Furthermore, a relief valve 16 is installed at one end of the hydraulic oil conduit 18.
Even if the oil pressure of the hydraulic oil 17 should rise abnormally, the safe operation of the entire machine can be maintained. As shown in FIGS. 6 and 7, the pump 14 is also fixed to the base with bolts.

The upper punch 6 protruding from the ram 5 further presses the material tube 2 downward, shortening the length of the tube, increasing the hydraulic pressure inside the tube, and reaching a hydraulic pressure of, for example, 950 to 1200 kg/-, which is capable of hydraulic bulging, and the material tube The tube wall of No. 2 bulges into the concave portion of the mold 4. This is as shown in the side views of FIGS. 8 to 10, that is, the inside of the material tube 2 in FIG. 9 shows a state in which the wall of the material tube 2 does not bulge into the recessed part of the mold 4 due to the suppression of the upper pump, and FIG. 10 shows the completion of the hydraulic bulge process.

FIG. 11 is a completed sketch of the bicycle hanger/lug 1 as described above, with the bulging protrusions processed.

1a and 1b indicate openings that engage with the chain stay, + lc with the vertical pipe, and ld with the lower pipe, respectively.

Finally, the hanger lug 3, which is a product that has undergone the hydraulic bulging process, can be taken out from the mold 4 by any known method, and there are no particular difficulties.

As described above, the present invention utilizes a general-purpose press machine with low equipment costs, and uses high-quality synthetic rubber, which is widely used as a pressure medium, instead of high-quality synthetic rubber.

It embodies the hydraulic bulge forming method using common low-cost hydraulic fluid, and can be said to have particular advantages in the bicycle industry.

[Brief explanation of drawings]

The drawings are for carrying out the present invention. Figure 1 shows the position of the hanger lug on the bicycle, Figure 2 shows the material steel pipe, and Figure 3 shows the position of the hanger lug on the bicycle.
The figure shows the primary product after hydraulic bulge, Figure 4 shows the three-part mold,
Figure 5 is a top view of the assembled mold, Figure 6 is a cross-sectional view of the machine of the present invention, Figure 7 is a top view of Figure 6, and Figures 8 to 10 are Figure 11, which is a transition diagram of the hydraulic bulge process, shows the completed hanger/lug product. ■・・・Hanger/lug 11・・Rubber 2・・Material steel pipe 12・・Lower punch 3・・Pipe material after bulge 13・・・Plunger 4・・・・Gold Type 14...Pump 5
...Ram 15...Start 6...
Upper punch 16...S') -7 Valve 7...Punch 17...Hydraulic oil 8...
・Base 18...Oil conduit 9...Support 20...Oil tank 10...Bolt

Claims (1)

[Claims] An oil tank filled with hydraulic oil is fixed on the bed of a unidirectional reciprocating general-purpose press machine, a base is fixed to the bottom of the oil tank, and a recessed part for forming multiple protrusions of the hanger/lug is carved on the inside of the base. A three-part mold to be installed and a mold support that surrounds and supports the mold and is on an elastic body are installed, a raw steel pipe is charged into the mold, and the air inside the raw steel pipe is is replaced with the hydraulic oil, and the upper punch protruding from the ram of the press descends to contact and seal the upper end of the raw steel pipe in the mold, and further presses it.
The lower punch fixed on the base contacts and seals the lower end of the raw steel pipe and receives the pressure, and the raw steel pipe is compressed and at the same time its internal volume is reduced to about 0.5 to 0.7. The internal pressure of the hydraulic oil is increased, and the pipe wall of the material steel pipe bulges into the concave portion carved on the inner surface of the mold, and further has a plunger protruding from the same ram as the upper punch. A material characterized in that a spring-type pump is installed on the base, a communication conduit for the hydraulic oil is provided in the lower pump, in the base, and to the pump, and the conduit is connected to a relief valve in the oil tank. A method of hydraulic bulge forming of hangers and lugs using a press machine from steel pipes.