JPH1071433A - Nozzle for vacuum formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent liquid spill in vacuum formation of a pipe with a simply structured vacuum forming nozzle for which no driving means is used. SOLUTION: In a vacuum forming nozzle N which is constituted of an engaging part 1 and a head part 2 and which is provided with a hole for injecting a forming liquid, the engaging part 1 is constituted of an engaging shaft part 11 formed integrally with the head part 2 and a slide member 12 slidable on the outer circumference of the engaging shaft part 11, the engaging shaft part 11 is formed in a tapered shape having the first, second, and third cylinder parts 111, 112, 113 each with a different outer diameter, the slide member 12 is provided with a small inside diameter part 122 engaging with the first cylinder part 111 and a large inside diameter part 21 engaging with the second cylinder part 112, a seal ring 8 which compression-deforms by a pressure from the slide member 12 is provided between the second cylinder part 112 and the large inside diameter part 21, and an atmospheric pressure chamber 8 in communication with the atmospheric air through a pressure relief hole 7 is also provided between the second cylinder part 112 and the large inside diameter part 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a nozzle used in hydroforming which is applied to, for example, bulging a pipe.

[0002]

2. Description of the Related Art When a pipe is hydraulically formed, it is necessary to seal a molding liquid inside the pipe to be molded. Therefore, various measures are taken for closing the end of the pipe to be molded. I have. As one of them, as shown in FIG. 6, the fitting part 101 of the nozzle 100 is fitted inside the end of the pipe P to be molded, and the outer mold 20 having the bead 201 is formed.
0 is provided outside the end of the pipe P to be molded, and the bead 201 of the outer mold 200 is cut into the outer peripheral surface of the end of the pipe P to be molded, whereby the inner peripheral surface of the pipe P to be molded is There is a conventional technique for increasing the adhesion to the outer peripheral surface of the fitting portion 101.

[0003] Another prior art is disclosed in Japanese Patent Laid-Open No. 6-3 / 1994.
As described in Japanese Patent No. 28158 (see FIG. 7), a slide member 302 is provided at the tip of the fitting portion 301 of the nozzle 300, and a seal ring 303 is provided between the sliding member 302 and the fitting portion 301. There is a conventional technique in which the seal ring 303 is compressed and deformed by driving the slide member 302 by a cylinder 400 to adhere to the inner peripheral surface of the pipe P to be molded.

[0004]

However, in the prior art, there was a problem that the adhesion between the pipe to be molded and the nozzle was not sufficiently obtained, and the prevention of liquid leakage was incomplete.

Further, in the prior art, since a driving means (cylinder) was required to drive the slide member, there was a problem that the mechanism became very complicated.

SUMMARY OF THE INVENTION An object of the present invention is to surely prevent liquid leakage during hydraulic forming of a pipe by a hydraulic forming nozzle having a simple mechanism without using a driving means.

[0007]

[Means for Solving the Problems]

(Solution 1) Solution 1 of the above problem (Claim 1)
A fitting portion fitted to the inside of the end of the pipe to be molded, and a head provided at one end of the fitting portion, which is constituted by a passage of a molding liquid to be jetted to the pipe to be molded; In the hydraulic forming nozzle provided with a forming liquid ejection hole, the fitting portion slides in the axial direction along a fitting shaft portion fixed to the head and an outer periphery of the fitting shaft portion. The fitting shaft portion is formed in a tapered shape having a first cylindrical portion, a second cylindrical portion, and a third cylindrical portion having different outer diameters, and The member has a cylindrical shape having a small inner diameter portion engaged with the first cylindrical portion having the smallest outer diameter and a large inner diameter portion engaged with the second cylindrical portion having the next smallest outer diameter. Formed between the third cylindrical portion of the fitting shaft portion and the large inner diameter portion of the slide member,
A seal ring that is compressed and deformed by the pressing force of the slide member and adheres closely to the inner peripheral surface of the pipe to be molded is provided, and is provided between the second cylindrical portion of the fitting shaft portion and the large inner diameter portion of the slide member. And an atmospheric pressure chamber which is at atmospheric pressure through a pressure release hole.

(Solution 2) A second solution of the above-mentioned problem is that the inner diameter of the first cylindrical portion of the fitting shaft portion and the inner diameter of the slide member is small. A seal ring is provided between the
A seal ring is provided between the second cylindrical portion of the fitting shaft portion and the large inner diameter portion of the slide member.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Embodiment 1 is a hydraulic forming nozzle corresponding to Solution 1 and Solution 2.

FIG. 1 is a partial cross-sectional side view showing a hydraulic forming nozzle according to a first embodiment. First, the configuration of a hydraulic forming nozzle N will be described with reference to FIG.

The hydraulic forming nozzle N includes a fitting portion 1 fitted inside the end of the pipe P to be formed, and a fitting portion 1
And a head 2 provided at one end of
A molding liquid ejection hole 3 serving as a passage of the molding liquid to be ejected to the molding pipe P is provided to penetrate the axis.

The fitting portion 1 has a fitting shaft 11 integrally formed with the head 2 and a slide member 12 provided so as to be able to slide on the outer periphery of the fitting shaft 11 in the axial direction. The fitting shaft portion 11 includes three cylindrical portions having different outer diameters (hereinafter referred to as a first cylindrical portion 111, a second cylindrical portion 112, and a third cylindrical portion 113 in ascending order of outer diameter). ), The slide member 12 is formed in the first cylindrical portion 111 of the fitting shaft portion 11.
And a large-diameter portion 122 engaged with the second cylindrical portion 112 of the fitting shaft 11 are formed in a cylindrical shape.

The fitting shaft portion 11 has a groove 114 on which the snap ring 4 is mounted on the outer periphery of the distal end of the first cylindrical portion 111 and a groove 115 on which the O-ring 5 is mounted on the second cylindrical portion 111.
It is provided on the outer periphery of the cylindrical portion 112, and the snapping 4 prevents the slide member 12 from falling off.
The seal between the second cylindrical portion 112 of the fitting shaft portion 11 and the large-diameter portion 122 of the slide member 12 is ensured by the ring 5.

The slide member 12 has a groove 123 in which the O-ring 6 is mounted on the inner periphery of the small inner diameter portion 121.
First cylindrical portion 111 and small inner diameter portion 12 of slide member 12
1 is secured. In the slide member 12, the outer circumference of the large-diameter portion 122 is formed to have a constant outer diameter that is the same as the outer diameter of the third cylindrical portion 113 of the fitting shaft portion 11. Is formed in a tapered shape whose diameter decreases toward the tip.

The fitting shaft portion 11 and the slide member 1
An atmospheric pressure chamber 8 communicating with the atmosphere outside the head 2 through a pressure release hole 7 is provided between the pressure chamber 2 and the pressure chamber 2.

Further, the third cylindrical portion 11 of the fitting shaft portion 11
3 and the large-diameter portion 122 of the slide member 12,
A seal ring 9 is provided, which is compressed and deformed by the pressure from the slide member 12 and closely adheres to the inner peripheral surface of the pipe to be molded. The seal ring 9 is formed of an elastic body such as rubber, resin, urethane, or the like. The outer diameter of the seal ring 9 is smaller than the outer diameters of the third cylindrical portion 113 and the inner diameter portion 122 in a non-compressed state. In this case, the outer diameter of the third cylindrical portion 113 and the outer diameter of the large inner diameter portion 122 are made larger. Also, the seal ring 9 is
Outer peripheral surface of the second cylindrical portion 112 and the first cylindrical portion 111
Are formed in a rectangular cross section having surfaces that are in close contact with the front surface of the slide member 12 and the rear end surface of the slide member 12, respectively.

FIGS. 2 and 3 show a state in which the nozzle N for hydraulic forming according to the first embodiment is fitted to the end of the pipe P to be molded. FIG. FIG. 3 shows a state before the liquid W is ejected, and FIG. 3 shows a state where the molding liquid W is ejected to the pipe P to be molded.

First, in a state before the molding liquid W is ejected to the pipe P to be molded, the internal pressure of the closed space of the pipe P to be molded is close to the atmospheric pressure and hardly differs from the internal pressure of the atmospheric pressure chamber 8. No pressure is applied to the slide member 12 to compress the seal ring 9. That is, the seal ring 9
The outer diameter of the third cylindrical portion 113 and the inner diameter large portion 12
The state smaller than the outer diameter of No. 1 is maintained.

Therefore, in this state, the pipe to be molded P
When the molding liquid W starts to be ejected from the molding liquid ejection hole 3, the molding is first performed from the gap between the outer peripheral surface of the fitting portion 1 of the compression molding nozzle N and the inner peripheral surface of the pipe P to be molded. The liquid W may leak. However, by injecting the molding liquid W into the pipe to be molded P at a speed faster than the leakage amount, the internal pressure of the closed space of the pipe to be molded P gradually increases. And a pressure difference between the pressure chamber 8 and the atmospheric pressure chamber 8. The pressure difference causes the slide member 12 to slide in a direction to compress the seal ring 9. The outer diameter of the seal ring 9 compressed by the slide member 12 is the third.
It becomes larger than the outer diameters of the cylindrical portion 113 and the large-diameter portion 121 and closely adheres to the inner peripheral surface of the pipe P to be molded. Since the seal ring 9 has a rectangular cross section having surfaces that are in close contact with the outer peripheral surface of the second cylindrical portion 112 of the fitting shaft portion 11, the front surface of the first cylindrical portion 111, and the rear end surface of the slide member 12, respectively. The outer diameter of the seal ring 9 increases at a high ratio with respect to the amount of elastic deformation, so that the pipe P
Because it is in close contact with the inner peripheral surface of the liquid, liquid leakage can be prevented quickly.

When the seal ring 9 comes into close contact with the inner peripheral surface of the pipe P to be molded, the internal pressure in the closed space of the pipe P to be molded further increases. The adhesion to the inner peripheral surface of the pipe P. Thereby, the molding liquid W in the molding pipe P can be completely sealed.

As described above, in the first embodiment, when the molding liquid W is ejected, the closed space of the pipe P to be molded and the atmospheric pressure chamber 8
The molding liquid W can be sealed in the molding pipe P by utilizing a pressure difference generated between the molding liquid W and the molding liquid W. The effect of being able to reliably prevent liquid leakage during hydraulic forming of the pipe P for use is obtained.

Further, between the fitting shaft portion 11 fitted inside the end of the pipe P to be molded and the slide member 12,
Since the two O-rings 5 and 6 are provided so as to sandwich the atmospheric pressure chamber 8, it is possible to reliably prevent the molding liquid W jetted into the pipe P to be molded from entering the atmospheric pressure chamber 8.

Further, since the seal ring 9 used in the non-compressed state has an outer diameter smaller than the outer diameters of the third cylindrical portion 113 and the large-diameter portion 121, the seal ring 9 is fitted to the end of the pipe P to be molded. At the time of joining, the seal ring 9 does not rub against the inner peripheral surface of the pipe P to be molded and is not worn or damaged.

(Other Embodiments) In the first embodiment, the seal ring 9 having a rectangular cross section is used. However, the cross section of the seal ring is not limited to a rectangle. For example, as shown in FIG.
The rear end face 122a of the seal ring 9a is inclined outward and the cross-sectional shape of the seal ring 9a is changed.
The seal ring 9a may be pushed outward by the rear end face 122a when the slide member 12 slides, with a trapezoidal shape having an inclined surface corresponding to a. By doing so, even when the differential pressure between the closed space of the pipe P to be molded and the atmospheric pressure chamber 8 is small, the seal ring 9a
Easily adheres to the inner peripheral surface of the pipe P to be molded. Also,
As shown in FIG. 5, the seal ring 9b has a circular O-
The cost may be reduced by using a ring.

[0025]

According to the first aspect of the present invention, there is provided a fitting part to be fitted inside the end of the pipe to be molded, and a head provided at one end of the fitting part. And a fitting shaft, wherein the fitting portion is fixed to the head, in a hydraulic forming nozzle provided with a forming liquid ejection hole serving as a passage of a forming liquid to be ejected to the pipe to be formed. And a slide member provided so as to be able to slide the outer periphery of the fitting shaft portion in the axial direction, wherein the fitting shaft portion has a first cylindrical portion and a second cylindrical portion having different outer diameters. A small inner diameter portion, which is formed in a tapered shape having a third cylindrical portion and the slide member is engaged with the first cylindrical portion having the smallest outer diameter;
Next, it is formed in a cylindrical shape having a large inner diameter portion engaged with the second cylindrical portion having a smaller outer diameter, and is formed between the third cylindrical portion of the fitting shaft portion and the large inner diameter portion of the slide member. A seal ring that is compressed and deformed by the pressing force of the slide member and adheres tightly to the inner peripheral surface of the pipe to be molded, and is provided between the second cylindrical portion of the fitting shaft portion and the large inner diameter portion of the slide member. Between,
The structure has an atmospheric pressure chamber that communicates with the atmosphere outside the head through the pressure release hole, so the differential pressure generated between the closed space of the pipe to be molded and the atmospheric pressure chamber when the molding liquid is ejected The molding liquid can be sealed in the pipe to be molded by using the nozzle. The effect is obtained that leakage can be reliably prevented.

In the invention according to claim 2, claim 1 is
In the hydraulic forming nozzle described above, a seal ring is provided between the first cylindrical portion of the fitting shaft portion and the small inner diameter portion of the slide member, and a second cylindrical portion of the fitting shaft portion is provided. Since a seal ring is provided between the slide member and the large-diameter portion of the slide member, 2 mm is provided between the slide shaft and the fitting shaft portion fitted inside the end of the pipe to be molded.
Since two seal rings are provided so as to sandwich the atmospheric pressure chamber, in addition to the above-described effects, the effect that the molding liquid ejected to the pipe to be molded can be reliably prevented from entering the atmospheric pressure chamber. Is obtained.

According to the third aspect of the present invention, there is provided the first aspect.
3. The hydraulic forming nozzle according to claim 2, wherein the seal ring is provided with an outer peripheral surface of a second cylindrical portion of the fitting shaft portion, a front surface of the first cylindrical portion, and a rear end surface of the slide member. Since the seal ring has a rectangular cross section with a surface that is in close contact with each other, the outer diameter of the seal ring increases at a high ratio to the amount of elastic deformation, and the seal ring comes into close contact with the inner peripheral surface of the pipe to be molded, so that liquid leakage is quickly prevented. The effect that it can be obtained is obtained.

According to the fourth aspect of the present invention, there is provided the first aspect.
The hydraulic forming nozzle according to the above and the hydraulic forming nozzle according to claim 2, wherein the rear end surface of the large-diameter portion of the slide member is an inclined surface inclined outward, and the seal ring includes:
Since the cross section has a trapezoidal shape having an inclined surface corresponding to the rear end surface, the seal ring can be in close contact with the inner peripheral surface of the molding pipe even when the pressure difference between the closed space of the molding pipe and the atmospheric pressure chamber is small. Thus, the effect that the liquid leakage can be more reliably prevented can be obtained.

According to the invention of claim 5, claim 1 is
In the hydraulic forming nozzle according to the above aspect, in the hydraulic forming nozzle according to the first aspect and the hydraulic forming nozzle according to the second aspect, since the seal ring has a circular cross section, cost can be reduced. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view showing a hydraulic forming nozzle according to a first embodiment.

FIG. 2 is a cross-sectional view showing a state in which the hydraulic forming nozzle according to the first embodiment is fitted to an end of a pipe to be formed.

FIG. 3 is a cross-sectional view showing a state in which the hydraulic forming nozzle according to the first embodiment is fitted to an end of a pipe to be formed.

FIG. 4 is a partial cross-sectional side view showing a hydraulic forming nozzle according to another embodiment.

FIG. 5 is a partial cross-sectional side view showing a hydraulic forming nozzle according to another embodiment.

FIG. 6 is a cross-sectional view showing a conventional hydraulic forming nozzle.

FIG. 7 is a cross-sectional view showing a conventional hydraulic forming nozzle.

[Explanation of symbols]

 P Pipe to be molded N Hydraulic molding nozzle 1 Fitting part 11 Fitting shaft part 111 First cylindrical part 112 Second cylindrical part 113 Third cylindrical part 12 Slide member 121 Large inner diameter part 122 Small inner diameter part 2 Head 3 Forming liquid ejection hole 4 Snap ring 5 O-ring (seal ring) 6 O-ring (seal ring) 7 Pressure release hole 8 Atmospheric pressure chamber 9 Seal ring

Claims (5)

[Claims] 1. A fitting portion (1) fitted inside an end of a pipe to be molded (P), and a head (2) provided at one end of the fitting portion (1). In the hydraulic forming nozzle (N), which is provided and has a forming liquid ejection hole (3) serving as a passage of the forming liquid to be ejected to the molding pipe (P), the fitting portion (1) A fitting shaft (11) fixed to the head (2), and a slide member (12) provided to be slidable in the axial direction on the outer periphery of the fitting shaft (11). The fitting shaft portion (11) is formed of a first cylindrical portion (1) having a different outer diameter.
11), the second cylindrical portion (112), and the third cylindrical portion (113)
A small inner diameter portion (121) in which the slide member (12) is engaged with the first cylindrical portion (111) having the smallest outer diameter.
And a cylindrical portion having a large-diameter portion (122) engaged with the second cylindrical portion (112) having the next smaller outer diameter, and a third cylindrical portion of the fitting shaft portion (11). A seal that is compressed and deformed by the pressing force of the slide member (12) and closely adheres to the inner peripheral surface of the pipe to be molded (P) between the slide member (113) and the large inner diameter portion (122) of the slide member (12). A ring (9) is provided, and a pressure release hole (7) is passed between a second cylindrical portion (112) of the fitting shaft portion (11) and a large inner diameter portion (122) of the slide member (12). A hydraulic forming nozzle provided with an atmospheric pressure chamber (8) at atmospheric pressure. 2. A first cylindrical portion (1) of said fitting shaft portion (11).
11) and a small inner diameter portion (12) of the slide member (12).
1), and a seal ring (6) is provided between the second cylindrical portion (112) of the fitting shaft portion (11) and the large inner diameter portion (122) of the slide member (12). 2. The nozzle according to claim 1, wherein a sealing ring is provided between the nozzles. 3. The hydraulic molding nozzle according to claim 1, wherein said seal ring is provided on said second cylindrical portion of said fitting shaft portion.
A hydraulic forming nozzle having a rectangular cross-section having surfaces that are in close contact with the outer peripheral surface of (12), the front surface of the first cylindrical portion (111), and the rear end surface of the slide member (12), respectively. 4. The hydraulic molding nozzle according to claim 1, wherein the rear end face (122) of the large inner diameter portion (122) of the slide member (12).
A hydraulic forming nozzle, characterized in that a) is an inclined surface inclined outward and the seal ring (9a) has a trapezoidal cross section having an inclined surface corresponding to the rear end surface (122a). 5. The nozzle according to claim 1, wherein said seal ring (9b) has a circular cross section.