JP2874494B2 - Corrugated pipe manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a corrugated pipe having a corrugated shape using high-frequency heating.

[0002]

2. Description of the Related Art Conventionally, a hydraulic bulging method has been used to form corrugated corrugated pipes. Japanese Utility Model Laid-Open Publication No. 63-85319 discloses an alternative forming method.

In the apparatus disclosed in Japanese Utility Model Laid-Open Publication No. 63-85319, the raw pipe is radially heated by a high frequency while the raw pipe is compressed in the axial direction by a pressurizing means. The corrugated pipe is formed by swelling in a predetermined direction and repeating this at a predetermined pitch. Therefore, in this method, the corrugated pipe can be easily formed without using a mold or a hydraulic unit.

[0004]

However, the apparatus disclosed in Japanese Utility Model Laid-Open Publication No.
There are the following problems. In the above case, since the local heating of the raw tube is performed using induction heating by high frequency, when forming one ridge at the end of the raw tube, the positioning block for holding the raw tube is also heated at the same time. As a result, as shown in the characteristics of FIG. 6, the end of the raw tube W cannot be sufficiently heated. Therefore, when compressing one crest at the end of the raw pipe W, the compressive force in the axial direction becomes insufficient as shown in FIG. Accordingly, as shown in FIGS. 2 and 3, the outer diameter D of the bulging portion W ₁ is smaller than the outer diameter D of the other bulge portion W _2.

[0005] corrugated pipes, for example, is interposed between a steering shaft of an automobile, to be utilized with a member for absorbing the shock, the bulging portion W ₁ of the outer diameter D is the outer diameter of the other of the bulge portion W ₂ D If not, the function as designed cannot be achieved. Thus, the variation of the bulge portion W ₁ on the quality of the corrugated pipe, a major problem.

An object of the present invention is to provide an apparatus for manufacturing a corrugated pipe capable of sufficiently heating an end portion of a raw tube held between positioning blocks by a high-frequency coil, focusing on the above problem. I do.

[0007]

To achieve the above object, a corrugated pipe manufacturing apparatus according to the present invention is configured as follows.

(1) A metal tube is sandwiched from both ends by a positioning block, and the tube is axially compressed in a state where the tube is locally heated by a high-frequency heating coil, so that the tube is radially attached to the tube. An apparatus for manufacturing a corrugated pipe in which bulging portions bulging outward are formed and the bulging portions are formed at regular intervals, wherein the positioning block is made of a non-metallic member.

(2) A metal tube is sandwiched from both ends by a positioning block, and the tube is axially compressed in a state where the tube is locally heated by a high-frequency heating coil, so that the tube is radially attached to the tube. In a corrugated pipe manufacturing apparatus in which a bulging portion that bulges outward is formed and the bulging portion is formed at regular intervals, the positioning block is transmitted through the positioning block of the magnetic lines of force generated by the high-frequency heating coil. It comprises heating control means for suppressing the amount.

[0010]

The following operation is performed in the corrugated pipe manufacturing apparatus configured as described above.

In the configuration (1), since the positioning block is made of a non-metallic member, no induction current flows through the positioning block during high-frequency heating, and the positioning block holding the end of the base tube is heated. Not done. Therefore, only the end of the raw tube can be sufficiently heated, and one peak of the bulging portion located at the end of the raw tube can be formed into a predetermined outer diameter.

(2) In the configuration of the above (2), the amount of the magnetic field lines passing through the positioning block can be controlled by the heating control means, so that the induced current induced in the positioning block can be suppressed to a small value. Accordingly, the end of the raw tube is sufficiently heated by that amount, and it is possible to form one peak of the bulging portion located at the end of the raw tube to a predetermined outer diameter.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a corrugated pipe manufacturing apparatus according to the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 7 show a first embodiment of the present invention.
In FIG. 7, reference numeral 1 denotes a base. Above the base 1, a lower frame 5 is arranged. Lower frame 5
, Two guide rods 6 extending downward are attached. Each guide rod 6 is slidably held on the base 1. As a result, the lower frame 5 can move up and down with respect to the base 1.

A first ball screw 21 extending downward is fixed to the lower surface of the lower frame 5. Base 1 has
A support block 22 screwed to the first ball screw 21 is rotatably mounted. A gear 23 is integrally attached to the support block 22. A bearing box 24 is fixed to the base 1. In the bearing box 24,
A shaft 25 is rotatably supported. A gear 26 meshing with the gear 23 on the bearing box 24 side is provided at the upper end of the shaft 25.
Is installed. A pulley 27 is provided at the lower end of the shaft 25.
Is installed.

In the base 1, a first servomotor 29 is provided via a bracket 28. A pulley 30 is attached to an output shaft of the first servomotor 29. The pulley 30 is connected via a belt 31 to the pulley 27 on the shaft 25 side. The rotation of the first servomotor 29 is transmitted to the shaft 25 via the belt 31,
Is transmitted to the support block 22 via the gear pair 26, 23. As a result, the lower frame 5 having the first ball screw 21 screwed to the support block 22 moves up and down when the first servomotor 29 rotates.

An upper frame 8 is arranged above the lower frame 5. A support block 32 is provided on the upper frame 8.
Is rotatably mounted. In the support block 32,
A second ball screw 33 extending in the up-down direction is screwed. A gear 34 is integrally attached to the support block 32. A bearing box 37 is fixed to the upper frame 8, and a shaft 35 is rotatably supported by the bearing box 37. A gear 36 that meshes with the gear 34 on the support block 32 side is attached to the lower end of the shaft 35. A pulley 38 is attached to the upper end of the shaft 35.

A second servomotor 40 is mounted on the upper frame 8 via a bracket 39. A pulley 41 is attached to an output shaft of the second servo motor 40. The pulley 41 is connected to the pulley 3 via a belt 42.
8 is connected. The rotation of the second servomotor 40 is transmitted to the shaft 35 via the belt 42 and further transmitted to the support block 32 via the gear pairs 36 and 34. Thereby, the second ball screw 33 screwed with the support block 32 is connected to the second servo motor 4.
When 0 rotates, it moves up and down.

The lower end of the second ball screw 33 is rotatably connected to a pressure moving plate 43 located below the upper frame 8. Two connecting rods 7, one of which is fixed to the lower frame 5 and the other of which is fixed to the upper frame 8, are inserted through the pressure moving plate 43. The pressurizing plate 43 moves up and down along the connecting rod 7 when the second servomotor 40 rotates.

On the lower surface of the upper frame 8, a pressure positioning block 10 is mounted. A pressure-receiving positioning block 11 is attached to the upper surface of the lower frame 5 so as to face the pressing-positioning block 10. The pressure positioning block 10 and the pressure receiving positioning block 11
It serves to support both ends of the raw tube W and to apply an axial load to the raw tube W. If the raw tube W is placed on the pressure receiving positioning block 11 and the pressurizing positioning block 10 is lowered by the operation of the second servomotor 40, an axial load can be applied to the raw tube W.

A high-frequency heating coil 17 is arranged above the lower frame 5 so as to surround the raw tube W. A cooling ring 18 is arranged inside the high-frequency heating coil 17 so as to surround the raw tube W. The high-frequency heating coil 17 and the cooling ring 18 are integrally supported by supporting means (not shown) extending from the base 1. High frequency heating coil 17
Serves to locally heat the raw tube W in the circumferential direction, and is connected to a high-frequency power source (not shown).

The cooling ring 18 serves to inject cooling liquid from an injection port 18a provided on the inner peripheral surface thereof and to locally cool the raw pipe W. This cooling liquid supply means (not shown) Is connected.

FIG. 1 shows a positioning block 11 for receiving pressure. The pressure receiving positioning block 11 is formed with a positioning portion 11a that fits with the inner peripheral surface of the end portion of the raw tube W and positions the lower portion of the raw tube W. The pressure receiving positioning block 11 is made of iron except for the positioning portion 11a. The positioning portion 11a is made of ceramic which is a non-metallic member. Thereby, the induced current by the high-frequency coil 17 does not flow through the ceramic positioning portion 11a.

The pressurizing positioning block 10 includes a raw pipe W
And a positioning portion (not shown) that fits over the inner peripheral surface of the end portion and positions the upper part of the raw tube W. The positioning portion (not shown) on the side of the pressing positioning block 10 is also made of ceramic, which is a nonmetallic member, as described above. As a result, an induced current by the high-frequency coil 17 does not flow through a positioning portion (not shown) of the pressing positioning block 10.

Next, the operation of the first embodiment will be described.

First, the raw tube W is placed on the positioning portion 11a of the pressure receiving positioning block 11, and then the second servomotor 40 is operated to lower the pressurized moving plate 43. A positioning portion (not shown) is brought into contact with the upper end of the raw tube W. Next, while applying a high-frequency voltage to the high-frequency coil 17, the second servomotor 40 is operated again, and an axial load is applied to the raw pipe W by the pressing positioning block 10 and the pressure-receiving positioning block 11.

The heating and the application of the load cause the heated portion of the raw tube W to locally expand, and at this stage, the operation of the second servomotor 40 and the application of the high-frequency voltage to the high-frequency coil 17 are stopped. Then, immediately after this, the cooling coil 18
Then, a cooling liquid is injected to cool the bulging portion, thereby completing the molding of one mountain.

Since the positioning portion 11a of the pressure receiving positioning block 11 is made of ceramic which is a non-metallic member, no induction current flows through the positioning portion 11a during high-frequency heating. Not heated by. Therefore, the high-frequency coil 1
7 can heat only the end of the raw tube W, and can sufficiently heat the end of the raw tube W as shown in FIG.

Therefore, as shown in FIG. 5, the heated portion of the raw tube W can be sufficiently compressed and deformed with a predetermined compressive load P, and _one of the bulging portions W ₁ located at the end of the raw tube W is formed. The peak can be formed to a predetermined outer diameter. Thus, by the moldable bulges W ₁ of the end portion of the base pipe W to the predetermined outer diameter, as shown in FIG. 3, the variation in outer diameter of the bulging portion W ₁ to _W-5 Will be resolved. The raw tube W has a diameter of 35 mm.
In wall thickness using those 0.8 mm, the outer diameter of the bulging portion W ₁ was set to 41.8mm plus or minus 0.1 mm.

[0030] swollen portion W ₁ of the end portion of the base pipe W is formed, by the operation of the first servo motor 29, the lower frame 5
Is lowered by a predetermined distance. When the lower frame 5 is lowered, the upper frame 8 connected thereto is also lowered, and accordingly, the raw tube W is also lowered while being supported by the pressure plate 10 and the pressure receiving plate 11.

After that, the rotation of the second ball screw 40 lowers the pressurized moving plate 43 again by the forming allowance, applies high-frequency power to the high-frequency heating coil 17, sprays the cooling liquid from the cooling coil 18, and so on. Then, the above operation is repeated, whereby a flare tube having a predetermined number of peaks can be obtained.

In the first embodiment, the operation of the pressure receiving positioning block 11 has been described. However, the same operation can be obtained in the pressing positioning block 10, and the bulging portion W _{5 at} the upper end of the raw tube W can be obtained. The outer diameter can be formed to the same size as the other outer diameters.

Second Embodiment FIG. 8 shows a second embodiment of the present invention. This embodiment is different from the first embodiment only in the configuration of the positioning block for positioning the raw tube.
Since the present embodiment conforms to the embodiment, the same reference numerals are given to the corresponding parts, and the description of the corresponding parts will be omitted, and only different parts will be described.

In the first embodiment, a part of the pressure-receiving positioning block is made of a non-metallic member. However, in this embodiment, the entire pressure-receiving positioning block 11 is made of iron. There is provided a ring-shaped heating control means 21 for suppressing the amount of lines of magnetic force passing through the ring. The heating control means 51 is made of a magnetic material or copper.

In this embodiment, the existing bulging portions W ₂ to W _{2 are formed} .
In order to prevent deformation due to heating of W _4, the heating prevention member 52 to the side and the bottom of the high-frequency coil 17 is provided. The heating prevention member 52 is for keeping the accuracy of the outer diameter of each bulging portion high, and is not unique to this embodiment.

In the second embodiment constructed as described above, the ring-shaped heating control means 51 provided on the outer periphery of the pressure receiving positioning block 11 is made of, for example, a magnetic material. The lines of magnetic force repel the lines of magnetic force from the heating control means 51, and the amount of lines of magnetic force transmitted through the pressure receiving positioning block 11 by the high-frequency coil 17 is suppressed.

As a result, the induced current induced in the pressure receiving positioning block 11 is extremely small, and the high-frequency coil 1
7, the heating of the pressure receiving positioning block 11 is significantly suppressed. Therefore, the end of the raw tube W is connected to the high-frequency coil 17.
By it is possible to sufficiently heat, can be molded outer diameter of the bulging portion W ₁ of the end portion of the base pipe W to a predetermined size.

[0038]

According to the present invention, the following effects can be obtained.

(1) In the apparatus for manufacturing a corrugated pipe according to the first aspect, since the positioning block for holding the end of the raw pipe is made of a non-metallic member, no induction current flows through the positioning block during high-frequency heating. The positioning block is no longer heated. Therefore, only the end of the raw tube can be heated by the high-frequency heating coil,
The outer diameter of the bulge formed at the end of the raw tube can be made the same as the outer diameter of the other bulges. As a result, a high-quality corrugated pipe can be obtained. When this corrugated pipe is used for a steering shaft of an automobile, desired performance can be sufficiently exhibited.

(2) In the apparatus for manufacturing a corrugated pipe according to the second aspect, since the heating control means is provided in the positioning block for holding the end of the raw tube, the positioning block for the magnetic force lines generated by the high-frequency heating coil penetrates. It is possible to suppress the amount of heat generation, and to suppress heating of the positioning block by the high-frequency coil. Therefore, only the end of the base tube can be sufficiently heated in the same manner as described above, and the outer diameter of the bulge formed at the end of the base tube is made equal to the outer diameter of the other bulge. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an apparatus for manufacturing a corrugated pipe according to a first embodiment of the present invention.

FIG. 2 is a front view of an end of a corrugated pipe formed by the apparatus of FIG. 1;

FIG. 3 is a characteristic diagram showing forming accuracy of a corrugated pipe formed by the apparatus of FIG. 1 and a corrugated pipe formed by a conventional apparatus.

FIG. 4 is a front view showing a compressed state of a raw tube by the apparatus of FIG. 1;

FIG. 5 is a characteristic diagram of a compressive load applied to a raw pipe in the apparatus of FIG. 1 and a conventional apparatus.

FIG. 6 is a characteristic diagram showing heating characteristics of an end portion of a raw tube in the apparatus of FIG. 1 and a conventional apparatus.

FIG. 7 is an overall configuration diagram of the apparatus of FIG. 1;

FIG. 8 is a sectional view of a main part of an apparatus for manufacturing a corrugated pipe according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Positioning block for pressurization 11 Positioning block for receiving pressure 11a Ceramic positioning part 17 High frequency heating coil 18 Cooling ring 51 Heating control member W Base tube W ₁ Swelling part at the end of base tube D Outside diameter of base tube

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-203217 (JP, A) JP-A-5-104157 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21D 15 / 06,19 / 08 B21C 37/00

Claims (2)

(57) [Claims] 1. A metal tube is sandwiched from both ends by a positioning block, and the tube is axially compressed while the tube is locally heated by a high-frequency heating coil, so that the tube is radially outwardly compressed. An apparatus for manufacturing a corrugated pipe, wherein the positioning block is formed of a non-metallic member. 2. A metal tube is sandwiched from both ends by a positioning block, and the tube is axially compressed in a state where the tube is locally heated by a high-frequency heating coil, so that the tube is radially outwardly attached to the tube. In a corrugated pipe manufacturing apparatus that forms a bulging portion that bulges in the direction and forms the bulging portion at regular intervals, the amount of magnetic force generated by the high-frequency heating coil that passes through the positioning block is transmitted to the positioning block An apparatus for manufacturing a corrugated pipe, comprising a heating control means for suppressing the occurrence of heat.