JPH0731841Y2 - Cold Pilger Mill - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a combination of indentation shaping means in the rolling process of a metal tube by a cold pilger mill.

[0002]

2. Description of the Related Art The dimensional guarantee accuracy of a working pipe rolled by a conventional cold pilger mill is usually ± 0.25% or more with respect to a target outer diameter dimension and ± 5% with respect to a wall thickness dimension.
That is all. In order to secure stricter dimensional accuracy than this, it is necessary to separately perform a pushing process or a drawing process in a subsequent process. In order to pass through this pushing process or drawing process, another pretreatment process such as heat treatment, straightening, surface lubrication, mouthpiece (only drawing) is required. Therefore, in the processing of a pipe having an accuracy that cannot be obtained only by processing with a cold pilger mill, a pipe having an outer diameter larger by, for example, 2 to 3 mm is processed in advance with a cold pilger mill and then finished by pushing. As a result, the guaranteed accuracy is ± 0.15% or more for the outer diameter dimension and ± 4% or more for the wall thickness dimension.

FIG. 2 shows a moving path of a working pipe after a moving end of a roll die of a conventional cold pilger mill.
1, 2 is a roll die, 3 is a processing pipe guide, 4 is an outlet guide, 5 is a holding portion (outlet chuck), 6
Is a tubular portion. An inlet chuck (not shown) that holds the outer circumference of the mother tube inserted through the mandrel and a feeder are provided, and the mother tube is fed and rotated every time the roll dies 1 and 2 reciprocate once. To give to.

The working pipe guide 3 is provided following the moving end position of the forward movement of the roll dies 1 and 2, and further, the outlet guide 4 and the holding portion 5 are provided in the tubular portion 6 subsequently. The tubular portion 6 is rotatably supported by the base body 7 via bearings 8 and 9 so as to withstand a thrust load. The outlet guide 4 guides the processing pipe to the holding portion 5. The holding part 5 is a chuck that holds the outer circumference of the processing tube at three points. This holding part 5 allows the axial movement of the processed pipe due to the elongation of the pipe by rolling with the roll dies 1 and 2 and the feeding of the mother pipe by sliding.
In addition, it has a holding force to the extent that the rotation of the pipe performed at the same time as the feeding is also given from the holding portion 5 side. The rotation given at the same time as this feeding is given from one or both of the inlet chuck and the holding portion 5. That is, since the working pipe has not yet reached the holding portion 5 in the initial stage of rolling the mother pipe of a certain length, rotation is given only by the inlet chuck, and then the working pipe reaches the holding portion 5 and holds it. Then, rotation is given from both sides, and when the rear end of the mother tube passes through the inlet chuck, rotation is given only by the holding portion 5. The feeding is applied to the mother tube directly or via the succeeding mother tube from the rear end of the mother tube. Therefore, the inlet chuck and the holding portion 5 are always rotated in synchronization with each other, and for this reason, they are connected to each other via the gear 10 provided on the tubular portion, a gear (not shown) and a synchronous rotation shaft. Has been done. The holding member 5 has a holding member 5a in contact with the axially moving member 5b via the tapered portion 5c, and the pressing force for pressing the member 5b in the axial direction is adjusted, so that the holding pipe 5 has an appropriate holding force. It is designed to hold.

[0005]

As described above, there is a problem in that the dimensional guarantee accuracy is low in the rolling process of the pipe using only the conventional cold pilger mill. Pushing or drawing conventionally performed when higher precision is required has a problem in that it requires the pretreatment step as described above, and its pretreatment equipment and pushing or drawing equipment. There is a problem that the product cost will rise considerably.

The object of the present invention is to make it possible to obtain the processing accuracy by the processing in which the conventional cold pilger mill is combined with the pushing or the drawing by a simpler process and equipment than the conventional one. .

[0007]

According to the present invention, in a cold pilger mill, an indentation shaping die for a working pipe is provided after a working pipe guide provided following a moving end of a roll die.

[0008]

According to the present invention, since the push die shaping die is provided after the working pipe guide provided following the moving end of the roll die, that is, at a proper position of the working pipe moving path after exiting the roll die, The working pipe passes through the indentation shaping die by the moving action of the elongation and the feeding by the rolling of the cold pilger mill, and the diameter is reduced to a desired pipe diameter. In addition, in the existing cold pilger mill,
When an indentation shaping die is provided, it is generally possible to reduce the outer diameter to about 3%. In addition, the ellipticity of the processed pipe coming out of the cold pilger mill is 0.5%.
There is more. Therefore, the reduction ratio of the outer diameter by the die is about 3
% To 0.5% is appropriate. Since it is passed through the indentation shaping die, the accuracy is significantly improved as compared with the accuracy of the rolled pipe made only by the roll die.

[0009]

EXAMPLE 1 In the first example, the outlet guide 4 in the conventional cold pilger mill shown in FIG.
The die structure 20 shown in FIG.

The die assembly 20 includes a cylindrical body 21 as shown.
Has a guide portion 22 on the inlet side (left side in the drawing) of the die 23, and the die 23 is accommodated in the die 23 so as to be rotatable and slightly axially displaceable following the guide portion 22.
Is pressed toward the inlet side by the member 24 and the spring 25. In the figure, reference numeral 26 is a cylindrical body, 27 is a bent leaf spring, which is provided so as to contact the outer periphery of the cylindrical body 26 and the inner periphery of the cylindrical body 21 at three points respectively, and the die 23 is slightly in the direction perpendicular to the axis. Can be displaced. In Figure 1, the upper half is the die 2
3 is a state in which the die 24 is moved to the inlet side, and the lower half is a state in which the die 24 is moved to the outlet side.

The axial movement of the die 23 takes into consideration the prevention of film breakage of the lubricating oil film. The inner diameter of the die 23 corresponds to the outer diameter of the desired processing tube, and the roll die 1,
2 is a die that can be processed into a pipe having an outer diameter that is about 3% larger than the inner diameter.

When a pipe is processed in the cold pilger mill provided with the die structure 20, if the mother pipe is supplied from the inlet side, it is rolled by the roll dies 1 and 2 in substantially the same manner as the conventional one, and then by the die 23. It is indented and shaped into the desired tube and comes out. In this indentation shaping, the die 23 is moved to the position shown in the lower half of FIG. 1 by the indentation of the processing tube. Even if the die 23 is slightly eccentric from the passage of the machining pipe, the eccentricity is automatically corrected by the displacement of the die 23 in the direction perpendicular to the axis, and the eccentricity allows the die 23 to rotate together with the machining pipe. There is no hindrance to the rotation of the processing pipe.

In the second embodiment, although not shown, the die 23 is shrink-fitted and fixed to the conventional outlet guide 4,
The outlet chuck 5 is not operated, that is, in the released state or the removed state.

In the apparatus of the second embodiment, the die 23 has the function of the outlet chuck 5. In the processing pipe that passes through the die 23, the die 23 is fixed to the outlet guide 4, and the outlet guide 4 has a tubular portion 6
Since the processing pipe is passing through the die 23, the processing pipe is held by the die 23, and when the cylindrical portion 6 that rotates in synchronization with the inlet chuck rotates, the rotation of the processing pipe is given to the processing pipe. You can

In the first embodiment, the die 23 is provided at the position of the outlet guide 4 of the conventional cold pilger mill, but in this case, the outlet chuck, that is, the holding portion 5 is present. It may be provided at any position after the machining pipe guide 3 as long as it is rotatably provided.

The following table shows the results of actual processing using the apparatus of the second embodiment and the results of processing using only the conventional cold pilger mill as a comparative example. The used mother tubes are all bearing steel (SUJ-2), but the dimensional schedule of the example is the mother tube outer diameter 60.0 mm, wall thickness 7.0 mm, intermediate product (roll die 1, 2 Where
Outer diameter 31.2 mm, wall thickness 3.5 mm, finished product (die 2
3) Outer diameter 30.80mm, wall thickness 3.5mm
In the comparative example, the outer diameter of the mother tube is 55.0 mm, the wall thickness is 7.0 mm, the outer diameter of the finished product is 30.80 mm, and the wall thickness is 3.5.
mm.

[0017]

[Table 1]

Σ _{n -1 in} Table 1 is the outer diameter dimension variation (m
m) and ε are the average value (mm) of the difference between the maximum outer diameter and the minimum outer diameter of the same cross section, and δ is the average value (mm) of the dial gauge deflection width by the 90 ° V block.

From these results, it can be seen that the machining according to the present invention can be machined with a distinctly higher accuracy than the conventional machining using only the cold pilger mill.

Further, from the data obtained from the respective processing pipes of the apparatus of the second embodiment and the conventional cold pilger mill, the following was confirmed. That is, according to the apparatus of the second embodiment, (a) it is possible to secure the dimensional guarantee accuracy by the processing in which the conventional cold pilger mill and the bushing described above are combined, and (b) the processing by only the conventional cold pilger mill. Of the outer surface and inner surface of the machined pipe in the longitudinal direction of the machined pipe in the cycle of the length of one feed and the extension of one roll die reciprocation, and the roll stand stop (the part where the temporary rolling is interrupted due to the addition of the mother pipe). ) Fluctuation of outer diameter (0.15-0.35m
m) can be eliminated, and (c) If the dimensional tolerance of the intermediate product from the cold pilger mill is about ± 1 mm in outer diameter, there is almost no effect on the accuracy of the finished product, so the life of the roll die is extended and doubled. As described above, (d) In the second embodiment, the outlet chuck can be omitted, so that a large-diameter thin-walled steel pipe (having a ratio of diameter to wall thickness of 17 or more) is prevented from being easily deformed into a triangular shape. There are effects such as doing. Although the mandrel is not mentioned in any of the above embodiments, the wall thickness and inner diameter can be restricted in some cases by extending the rear end of the mandrel and positioning it in the pressing die.

[0021]

[Effect of the Invention] This invention combines rolling processing of a metal pipe by a cold pilger mill with indentation shaping, and the indentation shaping utilizes the axial movement action of the processing tube due to elongation during rolling and feed of the mother tube. Therefore, it is only necessary to provide a conventional cold pilger mill with an indentation shaping die.
It is not necessary to use a separate equipment for pushing or drawing as in the prior art, and the pipe can be processed with the same good accuracy as in the case of using it. Moreover, as compared with the case of using a conventional cold pilger mill and a pushing or drawing device together, rolling and indentation shaping are continuously performed in one processing device, so that it is completely separated from rolling as in the past. The treatment step and either the pushing step or the drawing step can be omitted. That is, according to the present invention, since the pipes of the same degree of accuracy are machined, the equipment can be simplified and the process can be shortened as compared with the prior art, and thus the cost of the product can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a main part of a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a rear portion of a conventional cold pilger mill.

[Explanation of symbols]

 1 Roll Die 2 Roll Die 3 Processing Pipe Guide 4 Outlet Guide 5 Holding Part (Outlet Chuck) 6 Cylindrical Part 7 Base 20 Die Structure 23 Die (for Indentation Shaping)

Claims (1)

[Scope of utility model registration request] 1. A cold pilger mill, comprising a push shaping device having a push pipe shaping die for a working pipe after a working pipe guide provided following a moving end of a roll die. Pilger mill.