JP2874410B2 - Corrugated tube molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming apparatus for forming a corrugated tube from a raw tube using high-frequency heating.

[0002]

2. Description of the Related Art Heretofore, as an apparatus for forming a corrugated tube of this type, there is, for example, one described in Japanese Utility Model Laid-Open No. 63-85319. As shown in FIG. 4, a pair of pressure dies 1 and 2 for holding a raw tube W from both ends and applying an axial load to the raw tube, and a pair of pressing dies 1 and 2 for the circumferential direction of the raw tube High-frequency heating coil 3 for heating the cooling pipe and injecting cooling water into the raw tube;
(Not shown) for relative movement of the base tube W in the axial direction.

In such a molding apparatus, a pressing die 1,
After the raw tube W is sandwiched between the pair of pressure dies 1 and 2 using the positioning blocks 4 and 5 provided in the base 2, the raw tube W is locally heated in the circumferential direction by the high-frequency heating coil 3. When an axial load is applied from the pair of pressure dies 1 and 2 during or after the heating, the raw tube W locally swells and deforms, and then the coolant is injected from the high-frequency heating coil 3 immediately. For example, the shape of the bulging portion is fixed, and by repeating this cycle at a predetermined pitch in the axial direction of the raw tube W, a corrugated tube having a large number of peaks 6 is formed.

[0004]

However, according to the above-mentioned conventional molding apparatus, in order to facilitate the setting of the first raw tube W, in particular, one (the lower side) positioning block 4 is made long. Therefore, when the endmost ridge 6a approaching the positioning block 4 is formed, the electromagnetic induction effect of the high-frequency heating coil 3 extends to the positioning block 4 as a result. When heated, the raw tube W is heated over a wide range by heat conduction,
Since the pressing amount of the pressing dies 1 and 2 is constant, the height of the endmost peak 6a is smaller than the other peaks 6, and there is a problem that a desired shape cannot be obtained.

As a countermeasure against this, for example, the output of the high-frequency heating coil 3 is adjusted or the positioning block 4
May be formed from a non-magnetic material that is insensitive to electromagnetic induction, but in the former case, a difference occurs in the contact area between the base tube and the positioning block 4 due to dimensional variations of the base tube W. In the latter case, delicate control is required. In the latter case, the brazing portion is softened by induction heating and the positioning block peels off from the pressing die 1 for the purpose of brazing the positioning block 4 to the pressing die 1. Neither of them leads to fundamental measures.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent the height of the outermost peak from being reduced. An object of the present invention is to provide an apparatus for forming a corrugated tube that can secure desired shape accuracy.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a pair of pressure dies for clamping a raw tube from both ends and applying an axial load to the raw tube, A positioning block provided at each end and fitted to an end of the raw tube; a high-frequency heating coil for locally heating the raw tube in a circumferential direction and spraying a cooling liquid to the raw tube; A corrugated tube forming apparatus comprising: a pressure die and a means for relatively moving the high-frequency heating coil in the axial direction of the raw tube; and at least one of the positioning blocks corresponding to the pair of pressure dies corresponds to the pressure die. And a driving means for supporting and driving the positioning block.

[0008]

In the corrugated tube forming apparatus constructed as described above, the positioning block is immersed in the pressing die by the driving means so that the electromagnetic induction of the high-frequency heating coil does not reach the positioning block. Therefore, the raw tube can be efficiently heated. Moreover,
By making the positioning block protrude from the pressing die, it does not cause any inconvenience to the first positioning set of the raw tube.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an apparatus for forming a corrugated tube according to the present invention. In this figure, the same parts as those shown in FIG.
The description is omitted. In this embodiment, a concave hole 10 having a predetermined depth is provided in the lower press die 1, and the elongated positioning block 4 is slidably disposed in the concave hole 10; A cylinder 11 is disposed at the bottom of the cylinder 10 and a piston rod 12 extending from the cylinder 11 is provided.
, The lower end of the positioning block 4 is supported. That is, the positioning block 4 is
The piston rod 12 moves up and down in the concave hole 10 according to the expansion and contraction operation of the piston rod 12. Thus, the illustrated state shows that the piston rod 12 is at the extended end,
In this state, almost the entire positioning block 4 projects from the upper surface of the pressing die 1. On the other hand, the depth of the large hole 10 is set to be large enough to immerse almost the entire positioning block 4 at the contracted end of the piston rod 12 (FIG. 2).

In order to form a corrugated tube by the molding apparatus constructed as described above, as shown in FIG. 1, the piston rod 12 of the cylinder 11 is extended in advance, and the positioning block 4 is largely projected onto the pressure die 1. Leave it in the state. Then, first, the raw tube W is fitted into the lower positioning block 4 and the raw tube W is set on the lower pressing die 1. Then, the upper pressing die 2 is lowered, and both the pressing die The raw tube W is clamped between 1 and 2. Thereafter, the two pressing dies 1 and 2 are moved integrally with respect to the high-frequency heating coil 3, and the high-frequency heating coil 3 is positioned at the molding position of the first peak of the raw tube W. At this stage, as shown in FIG. First, the piston rod 12 of the cylinder 11 is shortened, and the positioning block 4 is immersed in the concave hole 10 of the pressing die 1.

Next, while maintaining the above state, power is supplied to the high-frequency heating coil 3 to locally heat the raw tube W in the circumferential direction. This heating is performed by time management, and when the heating is performed for a predetermined time (for example, about 2 seconds), the upper press die 2 is lowered by a predetermined distance. Then, the raw tube W locally swells and deforms, and immediately thereafter, the coolant is jetted from the jet port opened on the inner peripheral surface of the high-frequency heating coil 3 to cool the swelling portion. However, during the high frequency heating, since the positioning block 4 is immersed in the concave hole 10 of the pressing die 1, the electromagnetic induction action of the high frequency heating coil 3 does not reach the positioning block 4, so that the raw tube W Can be efficiently heated, and as a result, the size of the first peak 6a is sufficient.

Thereafter, the process moves to the second mountain forming. Prior to this process, the piston rod 12 of the cylinder 11 is extended as shown in FIG. Let it. Then, both the pressing dies 1 and 2 are integrally moved with respect to the high-frequency heating coil 3,
Similarly, as shown in FIG. 3, the high-frequency heating coil 3 is positioned at the forming position of the second peak of the raw tube W, and heating and cooling are performed in the same procedure as described above. This cycle is repeated at a predetermined pitch in the axial direction of the raw tube W, whereby a corrugated tube having a large number of peaks is formed. Therefore, when the cycle is repeated, the positioning block 4 is kept in a protruding state, so that the tube W does not shift during molding or moving.
Molding is stable. Here, the final shaping is performed in the vicinity of the upper positioning block 5. However, since the positioning block 5 is formed to be short, the raw tube W can be widened under the influence of the positioning block. There is no heating, so that the final peak shape accuracy is ensured.

In the above embodiment, the lower positioning block 4 is formed to be long and the upper positioning block 5 is formed to be short. In the present invention, the upper positioning block 5 is also formed to be long. Is also good, in this case,
The upper positioning block, like the lower positioning block 4, is provided so as to be able to protrude and retract from the pressure die 2. In the above-described embodiment, the position of the high-frequency heating coil 3 is fixed, and the two pressing dies 1 and 2 are moved.
Instead, the high-frequency heating coil 3 may be moved with the positions of the two pressing dies 1 and 2 fixed. further,
In the above embodiment, the two pressing dies 1 and 2 are arranged in the vertical direction to perform the molding in the vertical direction.
May be arranged in the horizontal direction and the molding may be performed in the horizontal direction.

[0015]

As described in detail above, according to the corrugated tube forming apparatus according to the present invention, the positioning block is provided so as to be able to protrude and retract, and the positioning block is retracted from the molding portion to be positioned at the extreme end. Since the peaks can be formed, the height of the outermost peak does not become small, and a corrugated tube having excellent overall shape accuracy can be formed. You can also adjust the output of high frequency heating,
Since there is no need to use positioning blocks made of special materials,
Overall, the reliability of the device is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a corrugated tube forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing a use mode of the present corrugated tube forming apparatus.

FIG. 3 is a cross-sectional view showing a use mode of the corrugated tube forming apparatus.

FIG. 4 is a cross-sectional view schematically showing a conventional corrugated tube forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressing die 2 Pressing die 3 High frequency heating coil 4 Positioning block 5 Positioning block 10 Concave hole 11 Cylinder 12 Piston rod W Base tube

Claims (1)

(57) [Claims] 1. A pair of pressing dies for holding a raw tube from both ends and applying a load in the axial direction to the raw tube, and positioning provided on each of the pressing dies to be fitted to an end of the raw tube. A block, a high-frequency heating coil for locally heating the raw tube in a circumferential direction and injecting a cooling liquid into the raw tube, and a pair of the pressing dies and the high-frequency heating coil in an axial direction of the raw tube. And a means for relatively moving the pressing die, wherein at least one of the positioning blocks corresponding to the pair of pressing dies is attached to the corresponding pressing die so as to be able to come and go, and An apparatus for forming a corrugated tube, further comprising a driving means for supporting and driving the positioning block on the die.