JP5740095B2 - Metal liner cup and method for producing the same - Google Patents

Description

  The present invention relates to a metal liner cup used for a pressure vessel or the like and a manufacturing method thereof, and more specifically, a metal liner cup having a relatively large diameter and a short length, such as a hydrogen tank for a fuel cell vehicle, and It relates to a manufacturing method.

  The use of fuel cells as a power source for next-generation automobiles is being studied. In general, a fuel cell vehicle is equipped with a pressure vessel filled with hydrogen fuel. However, since it is for in-vehicle use, it is required to have a large capacity and a light weight while its length is limited. As a pressure vessel that can satisfy such requirements, a pressure vessel is used in which a vessel body is formed of a metal liner made of aluminum or aluminum alloy, and a reinforcing fiber layer in which high-rigidity fibers are wound around the outer peripheral surface thereof. Yes.

  The metal liner used in such a pressure vessel is, for example, as shown in Patent Document 1 and Patent Document 2, a disk-shaped metal plate material as a material is placed on a die having a recess, and a punch is pushed in from above. The shape of the cup is manufactured by pressing (drawing) a metal plate.

As another metal liner manufacturing method, as shown in FIG. 6, the metal material 12 is put into the concave portion 10 of the die 11, and the punch 13 is pushed in from the upper side as shown in FIG. A method of extrusion molding (backward extrusion molding) into a shape is used.
In any case, the metal liner cup is processed so that the opening is narrowed in the next step, and the mouth is formed, whereby a pressure vessel having a desired shape is manufactured.

JP-A-5-337561 JP-A-5-050152

  As described above, a metal liner cup for a pressure vessel is formed by drawing or backward extrusion. However, in the former method by drawing (pressing), it is necessary to cut the material into a disk shape in advance before drawing, which increases the number of steps and labor, and increases the processing cost. Further, when cutting a large plate into a plurality of discs, end materials are generated between adjacent discs, and it is difficult to improve the yield of the material.

  In addition, the formed metal liner cup is affected by uneven metal flow (also called forging line) due to drawing, so the strength of the liner cylinder formed from the cup varies depending on the location, and the durability performance is It was scattered. Specifically, as shown in FIG. 8 (a), the metal flow of the plate A cut out in a disc shape flows in a certain direction as indicated by an arrow by rolling, but is drawn by a punch. Then, as shown in FIG. 8B, the plate A is pressed symmetrically with the punch as shown in FIG. 8B, and the direction of the metal flow at the positions (P1), (P2), and (P3) in the figure. Therefore, there is a problem that the durability of the liner cylindrical portion varies depending on the location and the durability performance varies.

  On the other hand, in the backward extrusion molding of FIGS. 6 and 7, in order to extrude the metal material 12 in a cup shape with the punch 13, a large punch load is required to form a large-diameter container all at once. For this reason, a large molding apparatus with high power is required. Further, the liner formed by backward extrusion molding also randomly generates metal flow at the bottom, and the body (side wall) metal flow occurs along the stretching direction (axis direction of the body). Therefore, there is a problem that strength and durability performance vary depending on the location of the product.

Therefore, the present invention is such that the bottom metal flow is formed in the radial direction from the center of the bottom, and the side metal flow is formed continuously from the bottom metal flow along the axis of the cup. An object of the present invention is to provide a metal liner cup having a uniform metal flow and no variation in strength and durability.
In addition, the present invention forms the bottom of the cup by side extrusion molding by pushing the metal material into the cavity with a punch while the cylindrical metal material is placed in the cylindrical space of the molding apparatus, and further extrusion molding The purpose is to provide a method for producing a cup for a metal liner with a uniform metal flow.

  Furthermore, the present invention provides a new manufacturing method capable of efficiently producing a metal liner cup having no variation in strength and durability performance with a simple structure and a compact device at low load and low cost. With the goal.

  The present invention makes it possible to form a cup for a metal liner in which the direction of metal flow is controlled by manufacturing a cup shape by a new method that has not been obtained so far.

That is, the metal liner cup of the present invention is an axisymmetric metal liner cup formed in a cup shape composed of a bottom portion and a side surface, and a boundary portion between the bottom portion and the side surface is smoothly curved in the axial direction. The bottom metal flow is formed in the radial direction from the bottom center, and the side metal flow is continuously formed along the axis of the cup continuously from the bottom metal flow.

Then, the metal liner cup of the present invention, bottom and Ri Do from the side, with the boundary portion between the bottom and sides of the axisymmetric cavity is formed in a cup shape formed to be curved, bottom center of the cavity And a molding apparatus comprising a mold in which a cylindrical space for material filling is formed along the axial direction of the cavity, and a punch for pressing the metal material filled in the cylindrical space. Then, with the cylindrical metal material placed in the cylindrical space of this molding device, the bottom of the cup is formed by side extrusion molding by pushing the metal material into the cavity with a punch, and further extrusion molding is continued. A cup for a metal liner is manufactured so as to form side surfaces.

According to this manufacturing method, the metal material filled in the cylindrical space is formed radially from the center of the bottom by side extrusion, and further, the side surface is formed along the axial direction of the cup. Since the cups are formed symmetrically in this way, the metal flow also has a radial bottom, and the side surfaces are formed along the axis, so that a uniform metal flow cup for a metal liner is formed.
Further, since the diameter of the cylindrical space can be made smaller than the inner diameter of the cavity, the punch load can be reduced, and a compact molding apparatus can be realized.
Furthermore, at this time, the large load generated when the cross-section reduction rate is increased as in general extrusion processing does not occur in this method, the upper and lower pressure areas are constant, in addition to the load during constant upsetting compression Only the direction change and the contact friction force when the material flows to the side are provided, and the load is lower than that of a general extrusion method.
In addition, since a cylindrical metal material is used, it is easy to pre-process the material before the forming process by cutting out a cylindrical bar material to an appropriate length. Moreover, the part discarded as a scrap is hardly generated.

  In the above invention, the metal liner cup may be formed integrally with a cylindrical convex portion outside the center of the bottom portion. By leaving the rear end portion of the cylindrical metal material, this portion can be used as a support portion during the subsequent processing, and support in the next step (for example, spinning processing for forming a mouth portion) can be achieved. It becomes easy.

Further, the boundary portion (a so-called shoulder portion) of the bottom and the sides of the cup for the metal liner is formed so as to curve along the axial direction.
In this way, since a smoothly continuous metal flow is formed, a homogeneous container having no variation in strength and durability can be stably produced.

Moreover, it is preferable that the cup for metal liners is either aluminum or an aluminum alloy.
A metal such as aluminum or aluminum alloy as a metal material can be easily subjected to side extrusion molding, so that the processing cost can be reduced.

  In the metal liner cup manufacturing method, the mold includes a mandrel that forms the inner surface of the cavity, a cylindrical space for filling the material, and a bottom portion and a side surface that continues to the bottom portion of the outer surface of the cavity. You may make it provide the lower die | dye which forms the side surface following an upper die among an upper die and the outer surface of a cavity.

  By dividing the mold into three parts, a mandrel, an upper die, and a lower die, the molded metal liner can be easily taken out from the cavity.

In the above manufacturing method, the boundary portion between the bottom and sides of the cavity formed by the mandrel and the upper die, so that the axial direction of the cross section is formed so as to curve.

  This makes it easy for the extruded metal material to flow smoothly from the bottom cavity to the side cavity, and a continuous metal flow is formed, making it possible to stably create a homogeneous container with no variation in strength or durability. .

  In the above manufacturing method, the metal material is preferably cylindrical aluminum or an aluminum alloy. Since these metals can be easily subjected to side extrusion, the processing cost can be reduced.

Sectional drawing which shows one Example of the apparatus for manufacturing the cup for metal liners for pressure vessels concerning this invention. Sectional drawing of the cup for metal liners shape | molded by the shaping | molding apparatus of FIG. Sectional drawing of the metal liner which shape | molded the opening | mouth part in the metal liner cup of FIG. Sectional drawing of the cup for metal liners of another form shape | molded with the shaping | molding apparatus of FIG. Sectional drawing when carrying out screw processing on the convex part of the cup for metal liners of FIG. Sectional drawing which shows the metal mold | die by the conventional back extrusion molding. Sectional drawing which shows the state which pressed down the punch by back extrusion molding of FIG. Explanatory drawing which shows the direction of the metal flow by the conventional drawing process.

  The details of the metal liner cup and the manufacturing method thereof according to the present invention will be described below in detail with reference to the drawings showing embodiments.

  FIG. 1 is a cross-sectional view showing an embodiment of a molding apparatus used when manufacturing a metal liner cup of the present invention. In the forming apparatus A, an upper die 1, a lower die 2 and a mandrel 3 are combined so as to be disassembled, and a cavity 4 for forming a metal liner refund is formed between these joining surfaces. The cavity 4 is axisymmetric about an axis (axis) X, and is composed of a dish-shaped space 4a serving as a cup-shaped bottom and a cylindrical space 4b serving as a side surface (so-called trunk), and is dish-shaped. It is formed with the space 4a facing up.

  Above the cavity 4, a cylindrical space 5 that communicates with the dish-shaped space 4 a and passes through the upper die 1 along the axis (axis) X of the cavity 4 is provided. The cylindrical space 5 is a hole for introducing the metal material 6. The diameter of the cylindrical space 5 is smaller than the inner diameter of the cylindrical space portion 4 b of the cavity 4. The smaller this diameter is, the smaller the pressing load by the punch 7 described later can be. However, it is preferably 0.2D to 0.8D with respect to the inner diameter D of the cylindrical space 4b. In addition, the process with respect to the metal raw material 6 performed before inserting in the cylindrical space 5 can be simplified by matching the diameter of the cylindrical space 5 with the outer diameter of the cylindrical metal raw material 6 used for a process.

  As a guide for facilitating assembly of the mold (upper die 1, lower die 2, mandrel 3), a base plate 21, a support column 22, a ring guide 23, and an upper plate 24 are provided.

  A punch 7 for pressing the metal material 6 is inserted into the cylindrical space 5. The material of the metal material 6 is particularly preferably aluminum or an aluminum alloy, but the material is not limited as long as it is a formable material.

  Next, the processing operation by the molding apparatus A will be described. A cylindrical metal material 6 having the same diameter as the cylindrical space 5 is inserted into the cylindrical space 5 in a state where the axis X of the cavity 4 and the axis of the metal material 6 are aligned. Then, by pressing the metal material 6 with the punch 7 and pushing it into the cavity 4, the metal liner cup B shown in FIG. 2 is manufactured by side extrusion molding. At the initial stage when the metal material 5 is pushed into the cavity 4 by the punch 7, the metal material 5 is stretched and radiates from the center of the dish-shaped space 4 a of the cavity 4 toward the curved shoulder of the space 4 a. To flow. At this time, since the axis of the columnar metal material 6 and the axis X of the cavity 4 are made to coincide, the stretched metal is evenly drawn in a circle from the center of the dish-shaped space 4a in the radial direction. To flow.

  Next, the stretched metal flows into the cylindrical space portion 4b from the curved shoulder portion of the dish-shaped space portion 4a, and flows downward along the cylindrical space portion 4a. As a result, the metal flow of the metal liner cup B is formed in the radial direction from the center of the bottom at the bottom, as indicated by the arrow in FIG. It is formed uniformly along the X direction. As a result, it is possible to obtain a high-quality metal liner cup having uniform strength regardless of the portion of the cylindrical body portion and having no product variation.

  The metal liner cup B manufactured in this way is a container-shaped metal liner B ′ having a narrowed opening 8 as shown in FIG. 3 by narrowing the opening by a known spinning process or the like in the next step. To be molded.

  In order to facilitate the processing in the next step, a convex portion 9 may be formed on the outer side of the bottom of the metal liner B as shown in FIG. This can be easily formed by leaving a part of the metal material 6 when the metal material 6 in the cylindrical space 5 is pushed out by the punch 7. In this way, when the mouth portion 8 is processed in the next step, the convex portion 9 can be supported by the chuck, and if it is cut off after spinning processing, the shape of FIG. 2 is finally obtained. You can also. Furthermore, as another method of using the convex portion 9, the metal liner cup B can be fixed by forming a screw hole 9a in the convex portion 9 as shown in FIG.

  As mentioned above, although the typical Example of this invention was described, this invention is not necessarily specified to said embodiment. For example, the shape of the cavity 4 of the molding apparatus A is modified within a range that does not affect the metal flow, so that the thickness of the bottom and the thickness of the body are changed, or the mouth is drawn in the next step. A thick portion for this purpose may be formed in the vicinity of the opening of the trunk.

In the above embodiment, the upper die 1 is disposed on the upper side and the mandrel 3 is disposed on the lower side. However, the mold may be disposed upside down.
Furthermore, the gap formed with the mandrel 3 in the initial material inflow portion at the bottom of the upper die 1 is not constant, but is initially increased and gradually reduced, and finally formed into a predetermined thickness, thereby improving the formability. The molding load can be reduced. Moreover, the thickness flowing into the gap can also be controlled by dividing the upper die 1 and performing backward pressing.
Others The present invention can be appropriately modified and changed within the scope of achieving the object and without departing from the scope of the claims.

  The metal liner cup of the present invention is used in a pressure vessel for filling hydrogen and other various pressurized substances, and is particularly applied to a hydrogen fuel tank of a fuel cell vehicle.

A Molding device B Metal liner cup 4 Cavity 4a Cavity dish space 4b Cavity cylindrical space 5 Material filling space 6 Metal material 7 Punch 8 Mouth 9 Protrusion

Claims (6)

An axisymmetric metal liner cup that consists of a bottom and side surfaces, and the boundary between the bottom and side surfaces is formed so as to be smoothly curved in the axial direction, and the metal flow at the bottom is directed radially from the center of the bottom. A metal liner cup formed, wherein the metal flow on the side surface is formed continuously from the metal flow on the bottom portion and along the axis.   2. The metal liner cup according to claim 1, wherein a cylindrical convex portion is integrally formed outside the center of the bottom of the cup. The metal liner cup according to claim 1, wherein the cup is made of aluminum or an aluminum alloy. Bottom and Ri Do from the side, with the axisymmetric cavity is formed in a cup shape and are formed to the boundary portion between the bottom and the side surface is curved, communicates with the bottom center of the cavity, in the axial direction of the cavity A cylindrical metal material was put into the cylindrical space using a molding device comprising a mold in which a cylindrical space for material filling was formed along with a punch for pressing the metal material filled in the cylindrical space. A method of manufacturing a metal liner cup, wherein the cup is manufactured by pressing the metal material into the cavity with a punch in a state so as to form a side surface by continuing extrusion from the bottom to the side surface. The mold includes a mandrel that forms an inner surface of the cavity, a cylindrical space for filling the material, and an upper die that forms a bottom portion and a side surface following the bottom portion of the outer surface of the cavity, and an outer surface of the cavity. The manufacturing method of the cup for metal liners of Claim 4 provided with the lower die | dye which forms the side surface following an upper die | die among them. The method for producing a metal liner cup according to any one of claims 4 and 5 , wherein the metal material is rod-shaped aluminum or aluminum alloy.

Images