JPH07115064B2 - Mandrel extractor for small diameter metal pipes - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mandrel extracting device used for producing a small diameter seamless metal tube which is difficult to process.

[0002]

2. Description of the Related Art Various methods and processes for manufacturing seamless hard-to-work metal pipes have been proposed in the past, but since they are difficult to process, they are carried out with problems such as unstable quality and reduced yield. This is the current situation.

Among them, the manufacture of a seamless metal pipe having a small diameter (hereinafter referred to as "metal pipe") is complicated and difficult, and a high level of technology is required. The small diameter referred to here is, for example, the outer diameter of the final product is 1 to 2 mm, and the wall thickness is 20.
It is about 30 μ.

The following are examples of conventional metal pipe manufacturing methods and processes. First, form a cylindrical shaped material, make a hole in the center, polish the outer peripheral surface of the material, then insert a mandrel into the hole in the center,
The outer diameter of the material is reduced by compressing the outer circumference of the material with a die or the like and pulling out the material, and the length of the material is extended to complete the one-step work. In order to further reduce the diameter of the material thus formed, that is, the metal tube, the mandrel inserted earlier is removed and replaced with another thin mandrel to continue the work. Therefore, a force is applied to the metal tube at a right angle to its length direction to deform the metal tube from a circular shape to an elliptical shape,
It was required to set a clearance (about 0.02 mm) between the elliptical metal tube and the circular mandrel. In order to set this clearance, the distance between the pair of rollers is adjusted so as to visually match the outer diameter of the metal tube drawn from the die, and the metal tube is sandwiched between the pair of rollers. It was compressed to obtain a predetermined deformation amount of the metal tube. The number of times that the thick mandrel is replaced with a thin mandrel sequentially varies depending on the material, diameter, quality, working temperature, etc. of the metal tube, but is usually about 30 to 30 times.

As a drawback of the conventional manufacturing method and process,
You can list the following:

Since the distance between the pair of rollers is set visually, accurate setting cannot be expected. Therefore, the metal tube is deformed too much and the quality thereof is deteriorated by excessive stress, or conversely, the deformation amount of the metal tube is insufficient and it is difficult to extract the mandrel from the metal tube.

(B) Since the metal tube and the pair of rollers are in contact with each other at two points, when the metal tube is deformed, the metal tube is easily bent.

(C) In manufacturing a metal tube, the metal tube is heated, but a pair of rollers remove heat from the metal tube, and
Especially when the metal tube is long, it is necessary to reheat because it is cooled during the manufacturing process, which is complicated.

[0009]

DISCLOSURE OF THE INVENTION The present invention is an improvement over the above-mentioned drawbacks of the prior art, in which the interval between a pair of rollers is accurately set so that the metal pipe is deteriorated due to excessive stress. To prevent the mandrel from being pulled out of the metal tube, and to speed up the work.
The metal tube is less likely to be bent during deformation processing of the metal tube, and further, the pair of rollers is prevented from taking heat from the metal tube, thereby eliminating the need for reheating the metal tube.

[0010]

According to the present invention, the distance between a pair of rollers is adjusted by using an instrument such as a digital meter, a guide is installed in front of the pair of rollers, and a bracket holds and holds the guide. The position of the guide with respect to the pair of rollers is adjusted, and the transferred metal pipe is supported by a total of three points, two points by the pair of rollers and one point by the bracket, and the pair of rollers is heated by the heating device. Is.

[0011]

The present invention adopts the above means,
Operate an instrument such as a digital meter to set the distance between the pair of rollers, and first insert the metal tube with the mandrel inserted into it.
It is sent to the guide and once stopped when the tip of the metal tube hits the pair of rollers. Next, one or both of the pair of rollers is rotated by starting the electric motor or the like, and the metal tube in which the mandrel is inserted is pinched between the pair of rollers and conveyed while being pinched. As a result, the metal tube is deformed by a predetermined amount, and a margin is created between the metal tube and the mandrel in a direction different from the clamping direction by 90 degrees, so that the mandrel can be easily removed from the metal tube.

The bracket adjusts the distance between the guide and the pair of rollers, and the heating device heats the pair of rollers to prevent the pair of rollers from taking heat from the hot metal tube.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 1 and 6 are a pair of rollers, 2 is a bearing for supporting a shaft 3 fixed to the roller 1,
4 is a coupling for connecting the shaft 3 and the electric motor 5, 7
Is a shaft that loosely supports the roller 6 and is fixed to the slider block 8. 9 is a bevel gear 13 and a male screw 24
And a fixed shaft supported by bearings 10 and 10. Shafts 11 and 11 loosely support the slider block 8 and are supported by bearings 12 and 12. The screw 25, which is fixed to the slider block 8, engages with the external screw 24. 14 is a bevel gear that meshes with the bevel gear 13,
It is fixed to the shaft 15. The shaft 15 is perpendicular to the shaft 9 and is supported by bearings 16 and 17. 18 is a digital meter, 19 is a handle for operating the digital meter,
The shaft 15 and the digital meter 18 are connected.

In FIG. 2, reference numerals 1 and 6 denote a pair of rollers, and 20 denotes a guide having a tapered hole for supporting and guiding the metal tube 26. Reference numerals 21 and 22 are heating devices, and 27 is a mandrel inserted into a hole formed in the center of the metal tube 26. 20 is a guide, which is a metal tube 2
The center position of 6 is regulated, and 23 is a pair of brackets for holding the guide 20 and adjusting the position with respect to the pair of rollers 1 and 6.

When the handle 19 of FIG. 1 is rotated to the left or right, the shaft 15, the bevel gear 14, the bevel gear 13, the shaft 9 and the male screw 24 are rotated according to the rotation angle, and the female screw 25 is fixed. The slider block 8 moves leftward or rightward. As a result, the roller 6 loosely supported by the shaft 7 fixed to the slider block 8 approaches or separates from the roller 1 and sets the pair of rollers 1 and 6 at a predetermined interval.

After this, in FIG. 2, when the metal tube 26 and the mandrel 27 are fed from below to above (actually in the horizontal direction), the tip of the metal tube 26 is located between the pair of rollers 1 and 6. I try to enter, but stop there. Subsequently, when the electric motor 5 is started, the roller 1 rotates counterclockwise, and the metal tube 26 has a pair of rollers 1 and 6 at the tip thereof.
It is bitten in between and transferred from the bottom to the top. At this time, the roller 6 rotates right. The metal tube 26 is deformed in a predetermined manner by the clamping pressure when it is transferred between the pair of rollers 1 and 6, and as a result, the metal tube 26 and the mandrel 27 are in a direction different from the clamping direction by 90 degrees. 3 (b), the mandrel 27 can be easily pulled out downward in FIG.

Since the metal tube 26 is supported at a total of three points, that is, two points by the pair of rollers 1 and 6 and one point by the guide 20, the straightness at the time of transfer is improved and bending deformation is less likely to occur. .

The heating devices 21, 22 include a pair of rollers 1,
6 is heated and a pair of rollers 1 and 6 are heated from the high heat metal tube 26.
Prevent heat from being taken away.

[0020]

Since the present invention is constructed as described above, the following effects can be obtained.

(1) By installing the guide, the metal tube is supported at a total of three points, that is, two points by the pair of rollers and one point by the guide, so that the metal tube is transferred as compared with the conventional two-point support. The straightness when turning is improved, and bending deformation hardly occurs.

(2) The distance between the pair of rollers can be set more accurately as compared with the conventional visual inspection by using an instrument such as a digital meter, and can be maintained constant during the work. . Therefore, the metal pipe is not deformed too much and its quality is not deteriorated by excessive stress, and on the contrary, the deformation amount of the metal pipe is insufficient, and it is not difficult to remove the mandrel from the metal pipe. , Work can be speeded up.

(3) Since the pair of rollers is heated by the heating device, the pair of rollers does not take heat from the high heat metal tube, and when the metal tube is long, it is cooled in the middle of the manufacturing process. However, reheating is not required, and it is possible to prevent the configuration of the entire apparatus from becoming complicated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a mechanism for adjusting a distance between a pair of rollers by operating a digital meter according to an embodiment of the present invention.

FIG. 2 is an overall schematic diagram of an embodiment of the present invention.

FIG. 3 is a diagram showing a cross-sectional shape of a metal tube and a mandrel according to the present invention, where (a) is a state where the metal tube before being pinched by a pair of rollers is not deformed, and (b) is a pinch state. The state where the metal tube is deformed after pressing is shown.

[Explanation of symbols]

 1,6 Roller 7 Axis 8 Slider block 18 Digital meter 19 Handle 20 Guide 21,22 Heating device 23 Bracket 26 Metal tube 27 Mandrel 28 Remove

Claims (1)

[Claims] 1. A gap between a pair of rollers is adjusted by using an instrument, a guide is installed in front of the pair of rollers, and the guide is held and adjusted by a bracket, and the metal pipe to be transferred is 3 pairs of roller and bracket
A mandrel extracting device for a small diameter metal pipe, which is provided with a heating device which is supported by points and heats the pair of rollers.