JPS6019770Y2 - Cylindrical correction jig - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cylindrical straightening jig suitable for heat treatment straightening of thin-walled cylinders.

Attempts to perform mechanical processing such as bellows forming or seaming on a cylinder formed by flow forming often fail due to work hardening caused by the flow forming process.

In this case, it is necessary to return the molded article to the state before the flow forming process, for example, by a method such as solution treatment which requires a considerably high temperature.

However, for processes that require high temperatures as mentioned above, heating significantly reduces the strength of the molded product, so cylindrical members with low strength, such as thin-walled cylinders, may collapse or deform significantly under their own weight. .

Moreover, there is a problem in that there is no longer any way to correct defects caused by such heat treatment.

As a method to solve these problems, Japanese Unexamined Patent Publication No. 48-
No. 10345, as shown in FIG. 1, discloses a method for straightening a cylinder 1 by inserting a mandrel 2 of a smaller diameter made of a material with a higher coefficient of expansion into the cylinder 1.

However, with this method, (a) there is a gap between the cylinder and the mandrel, so deformation cannot be corrected in a low temperature range;

(b) If scale or the like forms on the mandrel, it becomes difficult to remove the cylinder after straightening treatment, and the accuracy of the cylinder tends to deteriorate.

(c) If the cylinder is greatly deformed or the diameter of the end of the cylinder is small, it will be difficult to insert the mandrel.

Furthermore, when removing the mandrel after heat treatment, the cylinder is likely to be deformed again.

(b) Since it is necessary to create a mandrel with a thermal expansion coefficient suitable for the material of the cylinder, the number of mandrels increases accordingly for cylinders made of different materials.

There are drawbacks such as.

In order to solve the above-mentioned drawbacks, the present invention provides a jig for straightening a cylinder by heat treatment with a special structure so that the required straightening can be easily carried out.

Hereinafter, the present invention will be described by way of an embodiment with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a jig for straightening a thin cylinder, for example, a first jig 10. It consists of three parts divided into second jigs 11, 11' and third jigs 12, and is attached to the inside of the cylinder 1.

The first jig 10 has an outer diameter approximately equal to the inner diameter of the cylinder 1, and is formed into a cylindrical shape having a larger coefficient of thermal expansion and a thicker wall than the cylinder 1. , has a single cut 14 along its central axis.

Further, tapered portions are formed at both ends of the first jig 10, and the inner diameter of the end opening is larger than the inner diameter of the central portion.

The second jigs 11, 11 are formed in a frustoconical shape and have a circumferential surface that comes into close contact with the inner circumferential surface of the tapered part of the first jig 10,
In addition, the first jig 10 is provided with through holes 15.15 passing through it on the central axis, and is disposed at both ends of the first jig 10.

The third jig 12 includes a through hole 15 of the second jig 11, 11.
, 15, and has a pair of bolts 16a, 16b whose tips are positioned inside the first jig 10.

The opposing ends of the pair of bolts 16a, 16b are screwed into the coupling portion 17 and are integrally and coaxially coupled.

The coupling portion 17 is formed into a cylindrical body, and has female threads on its inner peripheral surface into which the bolts 16a and 16b are screwed.

This third jig 12 further includes a washer 18.18 in contact with the outer end surface of the second jig 11, and the bolt 16a.

16b, and a nut 19a that clamps and presses the second jigs 11, 11 onto the first jig 10 via the washer 18.18.
, 19b.

Therefore, the bolts 16a, 16b, the connecting portion 17. Washer 1
The third jig 12 consisting of the nuts 8 and 18 and the nuts 19a and 19b has a coefficient of thermal expansion smaller than that of the cylinder 1 as a whole.

In the correction jig having the above configuration, first, the first jig 10 is inserted into the cylinder 1, and then the third jig 12 is inserted into the first jig 1.
Insert it so that it passes through the inside of 0.

Next, the bolts 16a forming both ends of the third jig 12 are
, attach the second jig 11.11 to 16b, and install the washer 18.1.
8, connect the second jig 11°11 to the nuts 19a, 1
Tighten with 9b.

By this tightening, the peripheral surfaces of the second jigs 11, 11 are
The first jig 10 is pressed against the inner circumferential surface of the tapered portion so as to be clamped from both sides, and thereby the first jig 10 is pressed against the inner circumferential surface of the cylinder 1 to be corrected.

By the way, Figure 3 shows 18%Ni using the above correction jig.
Maraging steel (coefficient of thermal expansion 10.OX 10-6/
℃) with a wall thickness of 0.3rIrIn at approximately 800℃.
This shows the straightening results when heated to .

In this case, the first jig 10. Second jig 11. '11 is mild steel (thermal expansion coefficient 12.Ox 10-6
/°C), and the bolts 16a, 16b of the third jig 12
Titanium alloy (thermal expansion coefficient 9.Ox 10'/℃
), the connecting portion 17 was made of the same material as the cylinder 1.

In contrast to the arrow line A showing the test results with the heat treatment jig attached, the solid line B and the dotted line C indicate the straightening tool itself,
and the cylinder 1 from which the correction jig has been removed are shown for comparison.

On the other hand, FIG. 4 shows the results of testing the same cylinder 1 using the known technology shown in FIG. 1, in order to compare the above test results with the prior art.

In this case, 18% Ni maraging steel (thermal expansion coefficient 1
0. OX 10-6/℃)
8-8 stainless steel (coefficient of thermal expansion 17.OX 10-6
/°C) was used.

Arrow line A', solid line B' and dotted line C' are the third
These are test results corresponding to A, B, and C in the figure.

In these figures 3 and 4, points 20 to 24 are
The transformation of 18% Ni maraging steel is shown.

Comparing FIG. 3 and FIG. 4, in the known technique shown in FIG. 4, the adhesion between the cylinder 1 and the mandrel 2 deteriorates during the cooling process.
Moreover, it has been shown that in the transformation region, the close contact between the cylinder 1 and the mandrel 2 is significantly impaired due to the rapid change caused by the transformation.

However, according to the present invention shown in FIG.
As is clear from the complete agreement between experiment B and Cylinder 1, the cylinder 1 and the correction jig are in close contact with each other from start to finish and change integrally.
A good straightening effect is exhibited due to the difference in thermal expansion between the cylinder 1 and the first jig 10 and the contraction at the transformation point of the cylinder 1 made of maraging steel.

The main reason for such good results is that the first jig 10 and the second jig 11, 11 are in contact with each other at the tapered portions, and the first jig 10 has the cut 14 formed therein. ,
The first jig 10 attempts to correct the cylinder 1 as a cooperative effect of being able to always apply an appropriate pressing force to the cylinder 1 and that the first jig 10 has a larger coefficient of thermal expansion than the cylinder 1. The third jig 12 is made of a member with a low coefficient of expansion, so that there is little elongation in the central axis direction.
This is because the pressing force of the second jig 11.11 against the cylinder of the first jig 10 does not change much in response to temperature changes.

As described above, in the known technology, when the cylinder 1 is heat-treated and straightened, the cylindrical precision is degraded because the mandrel 2 cannot follow the expansion of the cylinder 1, whereas the present invention Not only is it easy to insert the tool, but it can also be brought into close contact with the cylinder 1 from beginning to end, and a good orthodontic effect can be achieved.

Furthermore, in the known technology, since a gap is provided between the cylinder 1 and the mandrel 2, straightening by low temperature heating is impossible, but in the present invention, the first jig 10 is always attached to the cylinder 1. Since they can be placed in close contact with each other, various effects can be achieved, such as the ability to achieve the desired straightening effect even in the case of low-temperature heating.

Furthermore, even if scale is attached to the correction jig, the cylinder 1 can be easily separated.

[Brief explanation of the drawing]

Figure 1 is a diagram of a known straightening jig for straightening a cylinder by heat treatment.
Fig. 2 is a partially sectional view of a correction jig according to an embodiment of the present invention, Fig. 3 is a graph showing test results using the correction jig shown in Fig. 2, and Fig. 4 is a graph showing test results using the correction jig shown in Fig. 2. 1st for comparison with Figure 3.
9 is a graph of test results using the correction jig shown in FIG. 9. 1... Cylinder (object to be corrected), 10... First jig, 11... Second jig, 12...
Third jig, 14... cut.

Claims (1)

[Scope of utility model registration request] It has an outer diameter that fits into the cylindrical object to be corrected, a single cut is formed along the central axis direction so that the outer diameter can be adjusted freely, and tapered portions are formed at the inner open ends of both ends. a cylindrical first jig having a coefficient of thermal expansion at least larger than that of the object to be corrected; a pair of second jigs that fit into the tapered portion of the first jig; A pair of second jigs, which are loosely inserted and whose ends are fitted to the tapered portions of the first jig, are engaged with the first jig so as to be able to press the first jig freely, and A cylindrical correction jig comprising: a third jig having a lower coefficient of thermal expansion than the correction body.