JPH0732052A - Method for working corrugated pipe and apparatus therefor - Google Patents

Abstract

PURPOSE:To shorten the working time of a tube stock and to improve the working accuracy of the tube stock. CONSTITUTION:One end of the tube stock 15 is held with a liner 32 and plural divided movable inner dies 34 fitted to the insert 32 are inserted into the tube stock 15 from the one end of the tube stock 15. The other end of the tube stock 15 is pressed toward the insert 32 and a corrugated forming surface in the divided movable outer die is brought into close contact with the outer peripheral surface of the tube stock 15. A diameter expanding rod 42 is inserted into a diameter expanding hole 34a in plural divided movable inner dies 34, and each divided movable inner die 34 is shifted sequentially toward the corrugated forming part 22a in a movable outer die 22 by inserting the diameter expanding rod 42. The tube stock 15 is formed into the corrugated shape by the champing pressure between the corrugated forming part 22a in the movable outer die 22 and the divided movable inner die 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a corrugated pipe using a mold.

[0002]

2. Description of the Related Art As shown in FIG. 7, a steering device for an automobile uses a corrugated pipe 1 made of metal for absorbing an external force. The corrugated pipe 1 is a corrugated metal pipe and can be easily deformed in the axial direction with a small load. The corrugated pipe 1 is required to be deformed by a predetermined amount under a predetermined load, and a large variation in processing accuracy should not occur.

The corrugated tube 1 is generally manufactured by hydraulic bulging or high frequency bulging. FIG. 8 shows a method of manufacturing the corrugated tube 1 by hydraulic bulging. As shown in FIG. 8, a die 6 having a corrugated inner peripheral surface is arranged on the outer periphery of the base pipe 5, and the inside of the base pipe 5 is filled with a liquid 7 such as oil or water. Both ends of the raw pipe 5 are closed by a lid 9 having a packing 8. The base pipe 5 is deformed into an outer shape when the pressure of the liquid 7 filled inside increases, and is formed into a corrugated shape along the shape of the mold 6. As a prior art related to hydraulic bulge processing, for example, Japanese Patent Laid-Open No. 2-290626 is known.

FIG. 9 shows a state in which a corrugated tube is manufactured by high frequency bulging. As shown in FIG. 9, a part of the raw tube 11 is heated by the high-frequency coil 14 in a state where both ends of the raw tube 11 are regulated by the blocks 12 and 13. When a part of the raw pipe 11 is heated, the raw pipe 11 is axially compressed by the upper block 12, and the heated portion bulges outward in the radial direction. Next, the bulging portion 11
After a is sufficiently cooled, the portion of the raw tube 11 which is separated from the bulging portion 11a by a predetermined pitch is heated, and similarly,
A bulge is formed by the compression of 1. By repeating this process, a corrugated corrugated tube can be obtained.

[0005]

However, the following problems exist in the hydraulic bulging and the high frequency bulging described above.

(1) In the case of hydraulic bulging, it is necessary to increase the pressure of the liquid, so that it takes time to increase the pressure of the liquid, resulting in poor productivity. Further, since the liquid is made to have a high pressure, the life of the sealing member such as packing is short, and liquid leaks frequently if the maintenance is not sufficient.

(2) In the case of high frequency bulge processing, the blank tube 1
Since 1 is heated one place at a time to form the bulged portion 11a, it takes a lot of time for processing and the productivity is poor. Further, in the case of high-frequency bulge processing, the bulging portion 11a is formed by buckling of the heating portion, and the bulging portion 11a is not regulated by the mold.
The accuracy of “a” varies, and it is difficult to improve the processing accuracy.

It is an object of the present invention to provide a corrugated pipe machining method and a machining device capable of shortening the machining time of a blank pipe and improving the machining accuracy of the blank pipe.

[0009]

The method and apparatus for processing a corrugated pipe according to the present invention for achieving this object are constructed as follows.

(1) One end of the raw pipe is held by a nest, and a plurality of split movable inner molds attached to the nest are inserted from one end of the raw pipe into the raw pipe, and the other end of the raw pipe is attached. Pressed toward the insert, the outer peripheral surface of the element tube, the divided waveform molding surface of the movable outer mold is brought into close contact, and the diameter expansion rod is inserted into the diameter expansion holes of the plurality of divided movable inner molds, By inserting the diameter-expanding rod, each of the split movable inner dies is sequentially moved toward the corrugated forming portion of the movable outer die, and the raw pipe is moved by the pressure between the corrugated forming portion of the movable outer die and the split movable inner die. A method for processing a corrugated pipe, which is characterized by being formed into a corrugated shape. (2) A movable outer die which is divided into a plurality of pieces in the circumferential direction, a corrugated portion is provided on the inner peripheral surface, and a cam surface is formed on the outer peripheral surface, and one end of a raw pipe set inside the movable outer die. And a pressing means for axially pressing the raw tube set inside the movable outer mold, the insert being held by the insert, and the insert attached to the insert. A plurality of split movable inner dies that are inserted inside and movable in the radial direction, and are in sliding contact with the cam surfaces of the movable outer dies, and are directed toward the raw pipe held by the insert and the pressing means by the sliding contact. A movable cam for moving the movable outer die, a first drive means for pressing the movable cam against the cam surface of the movable outer die, and a plurality of movable inner dies that are inserted into the expanded diameter holes of the movable inner dies. A diameter-expanding rod for moving the die toward the corrugated portion of the movable outer die, and an axis for moving the diameter-expanding rod in the axial direction. Processing apparatus of the corrugated tube, characterized in that and a second driving means for.

[0011]

In the method and apparatus for processing a corrugated pipe having such a structure, the movable outer die is arranged outside the raw pipe, and the split movable inner die is arranged inside the raw pipe. In this state, the diameter-expanding rod is inserted into the diameter-expanding hole of the split movable inner die, and the split movable inner die is moved (expanded) toward the waveform forming portion of the movable outer die. Therefore, the raw pipe is pressed by the corrugated forming portion of the movable outer die and the split movable inner die, and the raw pipe is formed into a corrugated shape.

As described above, since the blank pipe is pinched by the radial expansion rod moving outward in the radial direction of the split movable inner mold, the insertion speed of the radial expansion rod into the split movable inner mold is increased. , It becomes possible to form the corrugated pipe into a corrugated shape quickly, and it becomes possible to improve the productivity of the corrugated pipe as compared with the conventional hydraulic bulging and high frequency bulging.

Further, since the raw pipe is formed into a corrugated shape by the clamping pressure of the movable outer die and the split movable inner die, the precision of the raw pipe is higher than that in the high-frequency bulge machining in which the raw pipe is not restricted by the die. It can be significantly increased. In addition, since the base pipe is pressed in the axial direction by the pressing means during processing, the bulging effect (buckling effect) of the base pipe is enhanced and the wall thickness of the base pipe is made uniform.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a corrugated pipe processing method and processing device according to the present invention will be described below with reference to the drawings.

1 to 6 show an embodiment of the present invention. First, the structure of the corrugated pipe processing apparatus will be described. In FIG. 1, 20 has shown the corrugated pipe processing apparatus. The corrugated pipe processing apparatus 1 has a lower die base 21. The lower die base 21 is attached to a bed of a press machine (not shown). Lower mold base 2
A movable outer die 22 is disposed on the upper surface of 1. The movable outer die 22 is divided into two in the circumferential direction. The divided movable outer mold 22 is movable in the horizontal direction. Each movable outer die 22 is always pulled outward in the radial direction by a spring 23.

On the inner peripheral surface of the movable outer die 22, the corrugated portion 2 is formed.
2a is formed. The corrugated portion 22a is used for the base pipe 15
Is a part for forming the waveform. A cam surface 22 b having an inclined surface is formed on the outer peripheral surface of the movable outer die 22. The cam surface 22b has a function of moving the movable outer die 22 inward in the radial direction by contact with a movable cam 56 described later.

A hydraulic cylinder 24 as a pressing means is fixed to the lower die base 21. A stepped block 26 is attached to the rod 24 a of the hydraulic cylinder 24. The stepped block 26 holds one end of the raw pipe 15. The stepped block 26 is movable in the axial direction of the raw pipe 15 by expanding and contracting the rod 24 a of the hydraulic cylinder 24.

Above the lower mold base 21, the upper mold base 3 is provided.
1 is arranged. The upper die base 31 is attached to a ram of a press machine (not shown). Upper mold base 31
An insert 32 is attached to the lower surface of the. A step portion 32 a is formed on the lower surface side of the insert 32. Step 3
The other end of the raw pipe 15 is held by the 2a. A plurality of split movable inner molds 34 are provided on the lower surface of the step portion 32a.
Is installed.

The respective split movable inner molds 34 are stacked, and in this embodiment, they are stacked in five stages. Of the respective split movable inner molds 34, the split movable inner mold 34 located at the bottom is
It is received by the holder 38. Bolts 36 are formed on the holder 38 and each of the split movable inner molds 34 in a skewered shape.
Has been inserted. The threaded portion at the upper end of the bolt 36 is screwed into the insert 32. As a result, each of the split movable inner molds 34 is attached to the insert 32 in a suspended state.

FIG. 5 shows a perspective view of the split movable inner mold 34. As shown in FIG. 5, the split movable inner die 34 is divided into four in the circumferential direction. In the center of the split movable inner mold 34,
An enlarged diameter hole 34a is formed, one of which is a tapered portion.
A diameter expansion rod 42, which will be described later, is inserted into the diameter expansion hole 34a. On the outer periphery of the split movable inner mold 34,
An arcuate protrusion 34b is formed. Protrusion 34b
Has a function of forming the raw pipe 15 into a corrugated shape.

A holding groove 34c is formed in the split movable inner mold 24 concentrically with the expanded diameter hole 34a. A C-shaped spring 35 is attached to the holding groove 34c. As a result, the split movable inner mold 34 can move in the radial direction. An elongated hole 34d extending in the radial direction is formed in each of the divided portions of the divided movable inner mold 34. The above-described bolt 36 is inserted into the elongated hole 24d.

A hydraulic cylinder 41 as a first driving means is fixed to the upper die base 31. A diameter-expanding rod 42 is attached to the rod 41a of the hydraulic cylinder 41. The tip end portion of the diameter-expanding rod 42 is formed into a tapered portion 42a. The expanding rod 42 is connected to the hydraulic cylinder 40.
By expanding and contracting the rod 40a, the rod 40a can be moved in the axial direction of the raw pipe 15. When the rod 40a of the hydraulic cylinder 40 extends, the diameter-expanding rod 42 enters the diameter-expanding hole 34a of the split movable inner die 34, and the split movable inner die 34 moves outward in the radial direction.

A hydraulic cylinder 51 as a second driving means is fixed to the upper die base 31. A movable cam 56 is attached to the rod 51a of the hydraulic cylinder 51. The movable cam 56 includes a cam surface 22b of the movable outer die 22.
A cam surface 56a that can come into contact with is formed. The movable cam 56 descends due to the extension of the rod 51a of the hydraulic cylinder 51, and the straight portion 56b of the movable cam 56 and the movable outer die 2 are moved.
When the second straight portion 22c comes into contact, the movable outer die 22 is positioned at a predetermined position.

Each of the hydraulic cylinders 24, 41, 51 described above
Is connected to a hydraulic pressure generation source (not shown) via a solenoid valve (not shown). The operation sequence of the ram of the press machine and the hydraulic cylinders 24, 41, 51 is preset by a control means (not shown), and the respective parts are operated in a predetermined operation sequence.

Next, the corrugated pipe processing apparatus 2 described above.
A method of processing a corrugated pipe using 0 and its action will be described.

FIG. 4 shows a state where the upper die base 31 is raised. The stainless steel tube 15 is set in the stepped block 26 in this state. When the raw pipe 15 is set on the stepped block 26, the movable outer die 22 is pulled outward in the radial direction by the urging force of the spring 23.

When the setting of the base pipe 15 on the stepped block 26 is completed, the upper mold base 31 is lowered and the split movable inner mold 34 is inserted into the base pipe 15 from one side of the base pipe 15. The upper die base 31 stops when the end portion of the raw pipe 15 contacts the insert 32. When the lowering of the upper mold base 31 is stopped,
The hydraulic cylinder 51 as the second drive means operates, and the descent of the movable cam 56 is started. When the movable cam 56 descends, the cam surface 51a of the movable cam 51 and the cam surface 22b of the movable outer die 22 come into contact with each other, and the divided movable outer die 22 moves radially inward.

When the straight portion 51b of the movable cam 51 and the straight portion 22c of the movable outer die 22 are in contact with each other,
The movable outer die 22 is positioned at a predetermined position, and the movable outer die 2
The second corrugated portion 22a comes into close contact with the outer peripheral surface of the blank 15.
In this state, the hydraulic cylinder 4 as the first drive means
1 operates, and the expanding rod 42 starts descending toward the split movable inner mold 34 inserted into the raw pipe 15.

When the diameter-expanding rod 42 enters the diameter-expanding hole 34a of the split movable inner die 34, the split movable inner die 34 is radially outward, that is, the waveform of the movable outer die 22, as shown in FIG. The blank tube 15 moves toward the molding portion 22a, and is pushed outward by the protrusion 34b of the split movable inner mold 34. In this state, one of the base pipes 15 is axially pressed by the hydraulic cylinder 24 as a pressing means, so that the bulging effect (buckling effect) of the base pipe 15 becomes large. Therefore, the tube 1
Reference numeral 5 designates the waveform shaping portion 22a of the movable outer die 22 and the split movable inner die 3
It is pressed by the protrusions 34b of 4 and is easily formed into a corrugated shape.

At the time when the forming of the raw pipe 15 by the movable split inner mold 34 located at the uppermost position of each movable split inner mold 34 is completed, the straight inner peripheral surface of the expanded hole 34a of the movable split inner mold 34 is formed. And the straight portion 42b of the diameter-expanding rod 42 are brought into sliding contact with each other, so that the uppermost split movable inner mold 34 is locked in the radial movement. When the movement of the uppermost split movable inner die 34 is locked, the tapered portion 42a of the diameter-expanding rod 42 enters the diameter-expanding hole 34a of the split movable inner die 34 located thereunder, and the same molding as described above is performed. Be seen.

When the molding of the raw pipe 15 by the split movable inner mold 34 located at the lowermost portion of each of the split movable inner molds 34 is completed, a predetermined number of corrugated pipes are formed on the raw pipe 15 to form a corrugated pipe having a predetermined shape. Is obtained. When the forming of the raw pipe 15 is completed, the rod 41a of the hydraulic cylinder 41 as the first drive means contracts, and the pulling up of the expanded diameter rod 42 is started. From the expanding hole 34a of the split movable inner mold 34 to the expanding rod 4
When 2 is pulled out, the split movable inner mold 34 is moved radially inward by the urging force of the C-shaped spring 35, and is returned to the original state.

When the pulling up of the diameter-expanding rod 42 is started, the movable cam 56 is also pulled up by the hydraulic cylinder 51 as the second driving means, and the positioning of the movable outer die 22 by the movable cam 56 is released. As a result, the movable outer die 22 is moved outward in the radial direction by the urging force of the spring 23, and the contact of the corrugated surface 22a with the base pipe 15 is released.

When the movable outer die 22 is returned to a predetermined position, the upper die base 31 is raised and the plurality of split movable inner die 34 inserted into the raw pipe 15 are pulled up. When the upper mold base 31 is completely raised, the plurality of split movable inner molds 34 come out of the raw pipe 15 and the raw pipe 15 can be taken out.

As described above, by expanding the diameter of the split movable inner mold 34 by inserting the expanding rod 42, the base pipe 15 can be formed into a corrugated shape. By increasing the moving speed of the expanding rod 42, the base pipe 15 can be formed. It is possible to quickly mold 15. Further, the raw pipe 15 includes a movable outer mold 22 and a split movable inner mold 34.
Since the base tube 15 is axially pressed by the hydraulic cylinder 24 as a pressing means, the bulging effect (buckling effect) at the time of corrugation is enhanced, and the corrugated shape of the base tube 15 is formed. It also prevents the molded part from becoming particularly thin.

Since the split movable inner die 34 is divided into four in the circumferential direction, when the split movable inner die 34 is moved radially outward by the expanding rod 42, the split movable inner die 34 is divided.
A gap corresponding to the amount of movement is generated, and the corrugated portion of the raw pipe 15 does not form a perfect circle. However, when the corrugated pipe obtained by shaping the raw pipe 15 is used for a steering device of a vehicle, There is no problem at this point. This is because the corrugated tube used in the steering device has only to be deformed by a predetermined amount under a predetermined load, and therefore the shape itself does not matter.

[0036]

According to the present invention, the following effects can be obtained. (1) Since the raw tube is formed into a corrugated shape by moving the plurality of split movable inner dies radially outward by inserting the expanding rod,
By simply increasing the insertion speed of the diameter-expanding rod into the diameter-expanding hole of the split movable inner mold, the blank tube can be quickly formed into a corrugated shape.
Therefore, the processing time can be significantly shortened as compared with the conventional hydraulic bulge processing or high-frequency bulge processing, and the productivity of the corrugated pipe can be significantly increased. (2) Since the element pipe is formed by the pressure exerted by the movable outer die and the divided movable inner die, and the element tube is pressed in the axial direction by the pressing means, the element tube is moved by the movement of the divided movable inner die. At the time of forming a corrugated shape, the outer dimensions of the corrugated forming portion can be reliably suppressed, and the bulging effect (buckling effect) of the raw pipe can be enhanced to prevent the raw pipe from locally becoming thin. Therefore, there is no great variation in the processing accuracy of the raw pipe, and the processing accuracy can be greatly improved as compared with the high frequency bulge processing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state immediately after forming a raw pipe in a corrugated pipe processing apparatus to which a processing method of the present invention is applied.

FIG. 2 is a cross-sectional view showing a state after starting the forming of the raw pipe in the apparatus of FIG.

FIG. 3 is a cross-sectional view showing a state at the end of forming the raw pipe in the apparatus of FIG.

FIG. 4 is a cross-sectional view showing a state before starting the forming of the raw pipe in the apparatus of FIG.

5 is a perspective view of a split movable inner mold in the apparatus of FIG. 1. FIG.

6 is a cross-sectional view of FIG.

FIG. 7 is a front view showing an example of a vehicle steering system in which a corrugated tube is used.

FIG. 8 is a cross-sectional view showing a molded state of a corrugated pipe by conventional hydraulic bulge processing.

FIG. 9 is a cross-sectional view showing a molded state of a corrugated tube by conventional high-frequency bulge processing.

[Explanation of symbols]

 15 Element Pipe 20 Corrugated Pipe Processing Device 22 Movable Outer Mold 22a Corrugated Forming Part 22b Cam Surface 24 Pressing Means 32 Nesting 34 Divided Movable Inner Mold 34a Diameter Expansion Hole 41 First Driving Means 42 Diameter Expansion Rod 51 Second Driving Means 56 Movable cam

Claims (2)

[Claims] 1. An end piece of a raw pipe is held by a nest, and a plurality of split movable inner molds attached to the nest are inserted into the raw pipe from one end of the raw pipe, and the other end of the raw pipe is moved forward. By pressing toward the inserter, the corrugated molding surface of the divided movable outer mold is brought into close contact with the outer peripheral surface of the raw tube, and the diameter expansion rod is inserted into the diameter expansion holes of the plurality of divided movable inner molds. By inserting the diameter-expanding rod, each split movable inner die is sequentially moved toward the waveform shaping portion of the movable outer die, and the blank tube is corrugated by the sandwiching pressure between the waveform shaping portion of the movable outer die and the split movable inner die. A method for processing a corrugated pipe, which comprises forming into a corrugated pipe. 2. A movable outer die, which is divided into a plurality of pieces in the circumferential direction, a corrugated portion is provided on the inner peripheral surface, and a cam surface is formed on the outer peripheral surface, and a base pipe set inside the movable outer die. An insert for holding one end of the insert, a pressing means provided to face the insert for axially pressing an element tube set inside the movable outer mold, and attached to the insert, A plurality of split movable inner dies that are inserted inside the pipe and are movable in the radial direction, and the element pipe that is in sliding contact with the cam surface of the movable outer mold and is held by the insert and the pressing means by the sliding contact. A movable cam that moves the movable outer die toward the first movable means, a first driving unit that presses the movable cam against the cam surface of the movable outer die, and the movable cam is inserted into the diameter-expanding holes of the plurality of movable inner dies. A diameter-expanding rod for moving a movable inner die toward a corrugated portion of the movable outer die; Processing apparatus of the corrugated tube, characterized a second drive means for moving in the axial direction, further comprising a.