JPH0685945B2 - Method of forming annular flange on bottom of rotating container - Google Patents

Description

The present invention relates to a method of manufacturing a metal monoblock rotary container having a thick bottom and an annular rotary flange integrally provided as an extension of a side wall on the periphery of the bottom. The flange as described above usually acts as a connecting member and therefore must have very good mechanical resistance.

By way of example, the use of the method of the present invention to form a casing for a propulsion machine results in a flange as described above.

It is already known to manufacture hot or cold forged or drawn containers of containers which are thick on the sides and can be provided with forged or drawn flanges on the bottom.

However, this type of container is difficult to manufacture if it has a thick bottom, relatively thin sides and a high height to diameter ratio.

European patent application EP 51121 discloses a method of making such a container. This manufacturing method is such that the material is roughly formed by forging, and then the side wall is stretched by a rotary throttle while using a special means for preventing eccentricity, but these continuous operations are clear from the description of this European patent application. As such, it is very difficult to implement, and it is almost impossible to obtain a high quality product with optimum properties both dimensionally and mechanically under acceptable economic conditions.

Therefore, it has been considered that the bottom of the container is formed by a different method from the conventional method, but this has a disadvantage that the flange cannot be formed at the same time.

Of course, it is well known that the flange can be attached to the bottom of the metal container by suitable fastening means such as screwing, welding, brazing, hoops and the like. However, the connection between the flange and the container is still fragile, and since the connection must be reinforced in order to obtain sufficient resistance, the economical efficiency of the entire device is still a problem.

For the above reasons, the possibility of integrally forming the rotary flange surrounding the bottom of the monoblock container with the container has been pursued.

More specifically, a method has been investigated in which a flange is provided around the periphery of a preformed container bottom by subjecting its thick wall to a repoussage at one end of the tube.

In the method of the present invention, a metal monoblock rotating container is placed on a rotating mandrel which is rotated by a driving means, and the front end of the mandrel is brought into contact with the bottom of the container. The side surface of the mandrel and the inner surface of the side wall of the container are in contact with each other with a slight gap or almost no gap. The front abutment surface of the rotary tailstock coaxial with the mandrel covers a portion of the outer surface of the container bottom. The tailstock rod applies an axial thrust in the mandrel direction to the bottom of the container. The tailstock is free to rotate and is therefore driven to rotate with the container by the mandrel. The maximum diameter of its sides is smaller than the outer diameter of the container and is determined to support the flange during molding and to guide its inner surface. A part of the metal forming the side wall of the container is drawn in the annular zone near the bottom of the container in the direction of the tail rod by means of a spatula to form a tail rod side extension of the side wall of the container and a side surface of the tail rod. Forming an annular protrusion that at least partially covers the.

The metal drawing operation is at least one spinning that is free to rotate and runs on the outer surface of the container side wall while exerting sufficient pressure to draw the metal in the connection zone between the bottom and side walls of the container. Preference is given to using rolls.

It is also preferable to use one or more rolls, one mounted on each roll support head, which can move at least translationally along two orthogonal axes. The movement of each support head is effected by a numerically controlled device or an adjustable numerically controlled device.

When using multiple rolls, distribute the rolls around the axis of rotation of the container. The spatula operation can be performed by one operation or a plurality of continuous operations as necessary.

The spatula drawing operation to form the flange is cold or hot depending on the mechanical properties of the metal or alloy of which the container is made.

Once the flange is formed, the side walls of the container are thinly stretched by cold or hot fluotournage.

The invention further relates to a container having a flange formed by drawing metal from the sidewall. The invention also relates to a container with a flange of this kind, having a bottom formed by a spatula.

Although the method of the invention is used particularly advantageously in the formation of propulsion device casings, the invention also relates to such applications.

Hereinafter, the features of the manufacturing method and the product of the present invention will be described in more detail with reference to the accompanying drawings with reference to non-limiting specific examples.

1 to 3 schematically show an embodiment of the flange forming method of the present invention.

The metal monoblock rotary container 1 shown in cross section has a thick wall surface and is placed on a mandrel 2. The mandrel rotates about axis 3 by means not shown.

The bottom 4 of the container abuts the front end 5 of the mandrel over its entire surface. The side face 6 of the mandrel is cylindrical in this view and is covered with the container side wall 14 with little or no gap.

A rotary tailstock rod 7 mounted so as to be rotatable around the coaxial shaft 3.
Abut the bottom of the container. This tailstock pushes the container bottom 4 against the mandrel front end 5 by applying thrust in the direction of arrow F. On both sides of the mandrel there are arranged two rolls 8,9 which can rotate about axes 10,11. Each roll is
Supported by movable heads (not shown), these heads translate in a plane defined by the two axes X and Y, i.e. in a plane substantially parallel to the mandrel axis 3.
These heads can also rotate about an axis substantially perpendicular to the plane XY to change the angle between the roll axes 10, 11 and the mandrel axis 3.

A known adjustable numerical controller causes the roll to move over the head over the container outer surface in the flanging zone,
Rotational running is performed while applying a predetermined pressure to the metal along the generatrix of the side wall to the surface.

The movement of the roll is along the outer surface 12 of the container bottom, from the connecting zone 13 between the container bottom and the side wall 14 to the side of the tailstock 7.
It is carried out in a spiral shape in 15 directions. The front surface 16 of the tailstock has a shape which conforms to the bottom 4 and is strongly pressed against this bottom.

The tailstock side surface 15 is configured to support its inner surface during molding of the flange.

Under such conditions, the metal will be stretched by the rolls to gradually form an annular edge and coat at least a portion of the side face 15 of the tailstock.

In the case of hard metals or alloys, such as steel, this operation must be carried out hot. Therefore, at least heating means for heating the roll action zone to a desired temperature and means for maintaining the temperature for the time required for forming the flange are required. To that end, heating by radio frequency, torch or any other means may be used.

When using steel such as 32CD4 according to French standards, for example, 8
It may be heated to a temperature of about 50 to 900 ° C.

FIG. 2 shows the flange forming start stage when the annular edge 17 is formed, and FIG. 3 shows the flange 18 after the forming is completed. In FIG. 3, the roll axes 10, 11 are substantially parallel to the axis 3.

In practice, it is advantageous to provide these axes with a variable angle of attack with respect to the axes 3 during successive operations performed by the rolls. The roll positions along axis 3 are usually determined so that the rolls are offset from each other. The number of rolls can be arbitrarily determined to 1 to 2, 1 to 3 or more as described above. The adjusting numerical control device allows the roll movements to be carried out, usually in a plurality of successive operations, with complete adjustment, resulting in a flange with dimensional characteristics that allows for complete regeneration.

After flanging, the container may be subjected to partial or total heat treatment if desired. The outer and / or inner surface of the container can also be scored to eliminate possible surface defects and improve dimensional accuracy.

Further, the container side wall 14 may be subjected to a hot or cold rotary squeezing to be thinly stretched.

It is also possible to provide an opening at the bottom of the container, in which case it is usually formed near the axis.

The method of the present invention is suitable for forming containers for various applications, and is particularly advantageous for forming propulsion casings. The present invention can be variously modified without being limited to the above-mentioned specific examples, and these are also included in the scope.

[Brief description of drawings]

FIG. 1 is a sectional view of a metal monoblock rotating body container placed on a mandrel to form a flange, and FIG. 2 is an explanatory view showing a stage of forming a flange around the bottom of the container of FIG. 1, FIG. 3 is an explanatory view showing a completed state of the flange. 1 ... container, 2 ... mandrel, 7 ... tailstock, 8, 9
…… Roll, 18 …… Flange.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michel Pitavie, France, 92420, Vaucresson, Avnil-le-Notre, 7 (56) References JP 48-8718 (JP, B1) JP 58 -34206 (JP, B2)

Claims (9)

[Claims] 1. A method for forming an annular flange on the peripheral edge of the bottom of a metal monoblock rotating container, wherein the container is placed on a rotating mandrel which is rotated by a driving means, and the front end of the mandrel is attached to the container. Abutting over the entire inner surface of the bottom so that the sides of the mandrel are in contact with the inner surface of the container side wall with little or no gap,
It is coaxial with the mandrel, has a front surface that partially covers the outer surface of the container bottom, has the function of applying axial thrust in the mandrel direction, and the maximum diameter of the side surface is smaller than the outer diameter of the container. The bottom of the container is pressed against the mandrel by a rotary tailing rod that is determined to support the inner surface of the flange and provide a predetermined contour, and then a spatula squeeze in the opposite direction to remove a portion of the container sidewall metal from the container bottom. An annular protrusion extending in the direction of the tail rod in the vicinity of the tail ring to form a tail rod side extension of the container side wall and at least partially covering the side surface of the tail rod. Method. 2. Running on the outer surface of the container side wall while being free to rotate about its own axis and applying sufficient pressure to stretch the metal in the connection zone between the bottom and side walls of the container. The method according to claim 1, characterized in that the metal drawing is performed by at least one spinning roll that is used. 3. At least one roll is mounted on a roll support head which is movable at least translationally along two orthogonal axes, the head being moved by a numerical control device. The method according to claim 2. 4. At least two rolls are used, each roll being mounted on a roll support head and distributed about the axis of rotation of the container. The method described in. 5. The method according to any one of claims 1 to 4, wherein the spatula drawing is performed cold or hot. 6. The method according to any one of claims 1 to 5, wherein the spatulation is performed by one operation or a plurality of continuous operations. 7. A metal monoblock rotary container characterized by having a flange formed of a coaxial annular protrusion formed by extending metal from the side wall as a side wall extension to the bottom side of the container. 8. The container according to claim 7, wherein the bottom is a bottom formed by spatula drawing. 9. The container according to claim 7, which has a side wall thinly extended by a rotary throttle.