Patent Description:
As metal cases capable of housing various articles, cases formed by drawing a metal plate with a pressing machine have been widely used heretofore. However, in some cases, so-called deep drawing cannot be performed with high accuracy on common metal materials of low ductility such as stainless, titan, etc. In addition, a drawing process is limited in a draw depth, and a drawing process performed beyond the limit of the depth causes a crack on the case, therefore, the depth of a case to be subjected to the deep drawing has been limited. Under such circumstances, <CIT> discloses a configuration of a case, in which instead of a deep drawing, a tubular side wall part formed by bending a metal plate in a tubular shape and welding both ends of the metal plate together, and a plate-like bottom part formed by cutting a metal plate are prepared, and then the bottom part is welded to the tubular side wall part so as to cover an open end of the tubular side wall part, to thereby manufacture the case. As another configuration, a configuration in which a bottom part is welded to a seamless tubular member that has been formed by extrusion or pultrusion may be applicable. Because these configurations do not need a drawing process, limitation of the depth of a case can be eliminated, and variation of a wall thickness can be curtailed.

<CIT> discloses a can body. <CIT> discloses a battery case having the features of the preamble of claim <NUM>.

However, in case in the configurations disclosed in <CIT> and said other configuration, a boundary part between the bottom part and the side wall part exists on the side peripheral surface, it is necessary, during welding the both parts, to largely move a welding device along the tubular side peripheral surface in a circumferential direction, or to rotate the side wall part and the bottom part as welding targets along the tubular side peripheral surface in a circumferential direction, therefore a workability is poor. On the other hand, in case the boundary part between the bottom part and the side wall part exists on the bottom part, it is not necessary to largely move the welding device along the side peripheral surface, or to rotate the side wall part and the bottom part, therefore a workability is improved. However, weld beads that occur in an irregular shape by welding are exposed on the bottom surface and bulged from the bottom part, and thus the weld beads interfere with a placing surface when the case is placed, so that placement stability of the case deteriorates.

The present teachings have been made in view of the above-mentioned background, and it is intended to provide a metal case that is satisfactory in welding workability and can be stably placed on a placing surface.

The above object is solved by a metal case according to claim <NUM>.

In the above-mentioned metal case, the welding portion included in the boundary part between the bottom part and the side wall part that stands from an outer peripheral edge is exposed on a lower surface of the metal case in the standing direction of the side wall part. However, because the bottom part has a lower end that is located lower than the welding portion in the standing direction, irregular weld beads included in the welding portion are not bulged downward from the lower end of the bottom part even if the welding portion is formed by welding from downward in the standing direction. Therefore, when the metal case is placed on a placing surface, the lower end of the bottom part contacts the placing surface, so that the weld beads of the welding portion will not contact the placing surface. Therefore, a welding workability is satisfactory, and the metal case can be placed stably.

As mentioned above, according to the present teachings, a metal case that is satisfactory in welding workability and can be stably placed on the placing surface can be provided.

The outer peripheral edge of the bottom part preferably has a flange portion that is located on the upper side in the standing direction than the lower end of the bottom part is, and the flange portion and the side wall part are preferably welded together to form the welding portion. In this case, the flange portion can be used as a guide for welding, so that the welding workability is improved.

The flange portion is preferably formed thinner than the central region of the bottom part. In this case, the flange portion can be easily located on the upper side than the lower end of the bottom part in the standing direction, so that forming workability of the flange portion is improved.

The flange portion preferably includes a bent portion that is bent toward the upper side in the standing direction and is bent toward the outer side in a plan view of the bottom part. In this case, the flange portion can be located on the upper side than the lower end of the bottom part in the standing direction with a simple configuration, and a moldability of the flange portion is improved.

The lower end is preferably located on the lower side in the standing direction of the side wall part within a range of <NUM>-<NUM> than the welding portion is. In this case, when the metal case is placed, weld beads of the welding portion do not contact a placing surface, and the bottom part of the metal case can be prevented from excessively increasing in thickness in the standing direction.

The lower end of the bottom part is preferably formed of a protruding part that protrudes to the lower side in the standing direction. In this case, the protruding part serving as the lower end of the bottom part surely abuts on the placing surface when the metal case is placed on a placing surface, and thus the welding portion can be surely prevented from abutting on the placing surface, so that placement stability of the metal case can be further improved.

The bottom part preferably has an inner periphery contacting part that abuts on an inner peripheral surface of the side wall part. In this case, when the bottom part is welded to the side wall part, positioning of the bottom part can be easily made, so that welding workability is improved.

A working example of the above-mentioned metal case is explained with reference to <FIG>.

A metal case <NUM> of the present working example has a bottom part <NUM> composed of a metal plate, and a side wall part <NUM> composed of a metal plate that stands from an outer peripheral edge <NUM> of the bottom part <NUM>.

A boundary part <NUM> between the bottom part <NUM> and the side wall part <NUM> includes a welding portion <NUM> formed by welding the both parts together.

The welding portion <NUM> is exposed on a surface 10a of the metal case <NUM> on the lower side Z1 in a standing direction of the side wall part <NUM>.

As shown in <FIG>, a lower end <NUM> that is an end of the bottom part <NUM> on the lower side Z1 in the standing direction of the side wall part <NUM> is located on the lower side Z1 than the welding portion <NUM> in the standing direction.

Hereinafter, the metal case <NUM> of the present working example will be described in detail.

A material for molding the metal case <NUM> of the present working example is a metal material, and can be selected appropriately in consideration of the properties of an item(s) to be housed, a use environment of the metal case <NUM>, a moldability of a molding material, etc. For example, in the case where the metal case is used as a case for a battery, stainless steel, steel, titanium, a titanium alloy, aluminum, an aluminum alloy, etc. can be used in consideration of corrosion resistance, weldability, etc..

The metal case <NUM> has no particular limitation on its outer shape, and the bottom part <NUM> may be formed in a rectangle, a circle, an ellipse, a quadrilateral shape with two longer sides and two circular arc short sides, a corner-rounded rectangle, etc. The side wall part <NUM> is formed to stand on the outer peripheral edge of the bottom part <NUM>.

In the present example, the metal case <NUM> has an almost rectangular parallelopiped shape as shown in <FIG>, and has the bottom part <NUM> and the side wall part <NUM>. The opposite side to the bottom part <NUM> is open to form an opening <NUM>. In the present example, the bottom part <NUM> and the side wall part <NUM>, which have been separately molded as shown in <FIG>, are welded to form one united body. The bottom part <NUM> is formed into an almost tabular shape and in a rectangle in a plan view. Among surface directions of the bottom part <NUM>, a direction that is parallel to one side of the bottom part <NUM> is defined as a width direction X, and a direction that is orthogonal to the width direction X is defined as a depth direction Y. The side wall part <NUM> is formed in a tubular shape having a bottom that forms a rectangular outline, and stands from each side of the bottom part <NUM>. The standing direction Z of the side wall part <NUM> is a direction orthogonal to the width direction X and the depth direction Y.

In the present example, as shown in <FIG>, the side wall part <NUM> is formed by bending a metal plate into a tubular shape and welding the ends together in an abutting state. In this way, a side wall weld portion <NUM> is formed. In the present example, the side wall weld portion <NUM> is configured so as not to locate at corners <NUM>. A side-wall lower end <NUM> of the side wall part <NUM> forms a lower-end opening <NUM> that opens in a square shape.

As shown in <FIG>, the bottom part <NUM> has the flange portion <NUM> provided on the outer peripheral edge <NUM> thereof. The flange portion <NUM> protrudes from the outer peripheral edge <NUM> of the bottom part <NUM> outwardly in the surface direction of the bottom part <NUM>. The way to form the flange portion <NUM> on the outer peripheral edge <NUM> of the bottom part <NUM> is not particularly limited, and a press working, a cutting work, etc. can be used. And, as shown in <FIG>, the bottom part <NUM> is put on the side-wall lower end <NUM> of the side wall part <NUM> such that the flange portion <NUM> abuts on the lower end surface 21a of the side-wall lower end <NUM>, which is a lower end of the side wall part <NUM>, and then, as shown in <FIG>, a laser beam is applied toward the upper side Z2 from the lower side in the standing direction Z in the figure as shown by an arrow L, so that the flange portion <NUM> and the side wall lower end <NUM> are welded together to form the welding portion <NUM>. The laser beam is not necessarily applied in a direction that is parallel to the standing direction Z, and may be applied in a direction set to the flange portion <NUM> obliquely from below the metal case <NUM>. It is noted that although each figure illustrates that a direction of laser irradiation is set upward from the downside of the figure, the laser beam is applied in an inverted direction of the aforesaid direction in practice, i.e., a direction directed from up to down in the gravitational direction. The welding measure is not limited, and TIG welding may be used in place of laser welding.

As shown in <FIG>, the welding portion <NUM> is exposed on the surface 10a of the metal case <NUM> on the lower side Z1 in the standing direction of the metal case <NUM>. In the present example, a whole of the boundary part <NUM> constitutes the welding portion <NUM>. The welding portion <NUM> is formed of weld beads, which has been formed over the entire circumference along the outer periphery of the bottom part <NUM> as shown in <FIG>, and produces an irregular configuration as a whole. In the present example, as shown in <FIG>, the welding portion <NUM> is located inside of an outer peripheral surface 20b of the side wall part <NUM> in the width direction X.

As shown in <FIG>, the lower end <NUM> is located on the lower side Z1 in the standing direction Z by a height H1 than the welding portion <NUM> is. The height H1 may be set, for example, within <NUM>-<NUM>, and it is set within <NUM>-<NUM> in the present example.

As shown in <FIG>, the bottom part <NUM> is set into the lower-end opening <NUM> of the side wall part <NUM> to produce an inner periphery contacting part <NUM>. The inner periphery contacting part <NUM> is configured to abut on at least a pair of surfaces in an inner peripheral surface 20a which are opposed to each other, and in the present example, the inner periphery contacting part <NUM> abuts on all of four surfaces in the inner peripheral surface 20a.

Although the thickness of a metal material for forming the metal case <NUM> is not particularly limited, it may be set to approximately <NUM>-<NUM>. In the present example, as shown in <FIG>, a thickness T1 of the bottom part <NUM> is <NUM>, and a thickness T2 of the side wall part <NUM> is <NUM>. A thickness T3 of the flange portion <NUM> may be set to <NUM> or more and less than the thickness T1 of the bottom part <NUM>, and in the present example, the thickness T3 is <NUM>. In other words, the flange portion <NUM> is formed thinner than the central region of the bottom part <NUM>. A width W of the flange portion <NUM>, which is a length W in the width direction X of a stepped portion <NUM> stepped between the lower end <NUM> and the flange portion <NUM>, may be set to <NUM> or more, and less than the thickness T2 of the side wall part <NUM>, and in the present example, the width W is <NUM>.

In addition, as shown in <FIG>, a distance T4 in the standing direction Z between the lower end <NUM> and the flange portion <NUM>, which is a depth T4 of the stepped portion <NUM> stepped between the lower end <NUM> and the flange portion <NUM>, may be set to <NUM> or more and less than the thickness T1 of the bottom part <NUM>, and in the present example, the thickness T3 is <NUM>. A thickness T5 of the inner periphery contacting part <NUM> from the flange portion <NUM> in the standing direction Z may be set to <NUM> or more, and less than the thickness T1 of the bottom part <NUM>, and in the present example, the thickness T5 is <NUM>.

Operational effects of the metal case <NUM> of the present example are described.

With regard to the metal case <NUM> of the present example, the welding portion <NUM>, which is included in the boundary part <NUM> between the bottom part <NUM> and the side wall part <NUM> that stands from the outer peripheral edge <NUM> of the bottom part <NUM>, is exposed on the surface 10a on the lower side Z1 in the standing direction of the side wall part <NUM>. However, because the bottom part <NUM> has the lower end <NUM> that is located on the lower side Z1 in the standing direction than the welding portion <NUM> is, irregular weld beads included in the welding portion <NUM> are not bulged to the lower side Z1 in the standing direction from the lower end <NUM> of the bottom part <NUM> even if the welding portion <NUM> is formed by welding from the lower side Z1 in the standing direction. Therefore, when the metal case <NUM> is placed on a placing surface, the lower end <NUM> of the bottom part <NUM> abuts on the placing surface, so that the weld beads of the welding portion <NUM> do not contact the placing surface. Consequently, welding workability is satisfactory, and the metal case <NUM> can be placed stably.

Moreover, in the present example, the outer peripheral edge <NUM> of the bottom part <NUM> has the flange portion <NUM>, which is located on the upper side Z2 in the standing direction than the lower end <NUM> of the bottom part <NUM> is, and the flange portion <NUM> and the side wall part <NUM> are welded together to form the welding portion <NUM>. Consequently, the flange portion <NUM> can be used as a guide for welding, and the welding workability is improved.

Furthermore, in the present example, the flange portion <NUM> is formed having the outer peripheral edge <NUM> of the bottom part <NUM> made thinner than the central region of the bottom part <NUM>. Consequently, it becomes easy to locate the flange portion <NUM> on the upper side Z2 in the standing direction than the lower end <NUM> of the bottom part <NUM> is, so that forming workability of the flange portion <NUM> is improved.

Furthermore, in the present example, the lower end <NUM> is located on the lower side Z1 in the standing direction Z of the side wall part <NUM> within a range of <NUM>-<NUM> than the welding portion <NUM> is. Consequently, when the metal case <NUM> is placed, weld beads of the welding portion <NUM> do not contact a placing surface, and the bottom part <NUM> of the metal case <NUM> can be prevented from excessively increasing in thickness in the standing direction Z.

Furthermore, in the present example, the bottom part <NUM> has the inner periphery contacting part <NUM> that abuts on the inner peripheral surface 20a of the side wall part <NUM>. Consequently, when the bottom part <NUM> is welded to the side wall part <NUM>, positioning of the bottom part <NUM> can be easily made, so that welding workability is improved.

It is noted that although in the present example, the bottom part <NUM> has the inner periphery contacting part <NUM>, the bottom part <NUM> may be configured so as not to have the inner periphery contacting part <NUM> instead, as in a Modification <NUM> (not covered by the independent claim) shown in <FIG>.

It is noted that although in the present example, the flange portion <NUM> is configured to abut on a lower end surface 21a of the side-wall lower end <NUM> of the side wall part <NUM>, in place of this configuration, it may be configured such that part of the bottom part <NUM> is set into the lower-end opening <NUM> of the side wall part <NUM> so that the flange portion <NUM> abuts on the inner peripheral surface 20a of the side wall part <NUM> as in a Modification <NUM> (not covered by the independent claim) shown in <FIG>.

In a Modification <NUM> (not covered by the independent claim) as another modification, a protrusion <NUM> may be protrudingly formed on the inner peripheral surface 20a of the side wall part <NUM> near the lower-end opening <NUM> in the configuration of the Modification <NUM>, as shown in <FIG>. According to the Modification <NUM>, the flange portion13 is allowed to abut on the protrusion <NUM>, and positioning of the bottom part <NUM> in the standing direction Z can be made easily.

A Modification <NUM> (not covered by the independent claim) as another modification may be configured such that a front edge of the flange portion <NUM> is bent toward the lower side Z1 in the standing direction, as shown in <FIG>. In this Modification <NUM>, a recessed part <NUM> is formed in the flange portion <NUM> on the inner side of its front edge, and welding is performed in the state that a tip surface 13a of the flange portion <NUM> and the lower end surface 21a of the side wall part <NUM> are set on the same plane. It is noted that also in the Modification <NUM>, the protrusion <NUM> may be protrudingly formed in the same manner as in the Modification <NUM> shown in <FIG>.

As mentioned above, according to the Working Example <NUM> and the Modifications <NUM> to <NUM>, the metal case <NUM> that is satisfactory in welding workability and can be stably placed on a placing surface can be provided.

In the metal case <NUM> of the present example (not covered by the independent claim), the thickness T1 of the central region <NUM> and the thickness T3 of the flange portion <NUM> in the bottom part <NUM> are made the same, and are set to <NUM>. With regard to the bottom part <NUM>, the flange portion <NUM> is formed by performing a press working on a metal plate to bend the outer peripheral edge <NUM> upward Z2 in the standing direction and produce the stepped portion <NUM>. In this way, the flange portion <NUM> is provided with a bent portion <NUM> that is bent toward the upper side Z2 in the standing direction, and is bent in either one of the width direction X or the depth direction Y, i.e., an outward direction in a plan view of the bottom part <NUM>. It is noted that in the present example, the same reference numbers are used for the same configurations as those in Working Example <NUM> to omit the explanation.

In the metal case <NUM> of the present example, the flange portion <NUM> can be located on the upper side Z2 in the standing direction than the lower end <NUM> of the bottom part <NUM> is, with a simple configuration because it has the bent portion <NUM>, so that moldability of the flange portion <NUM> is improved. In addition, the present example also exhibits the same operational effects as those in the Working Example <NUM>.

It is noted that the inner periphery contacting part <NUM> that abuts on the inner peripheral surface 20a of the side wall part <NUM> may be provided to the bottom part <NUM> in the configuration of Working Example <NUM>, as in a Modification <NUM> (not covered by the independent claim) shown in <FIG>. The inner periphery contacting part <NUM> may be configured in the same way as in the Working Example <NUM>.

In addition, another configuration as in a Modification <NUM> (not covered by the independent claim) shown in <FIG> may be applied, in which part of the bottom part <NUM> is set into the lower-end opening <NUM> of the side wall part <NUM> so that the flange portion <NUM> abuts on the inner peripheral surface 20a of the side wall part <NUM>.

Moreover, in a Modification <NUM> (not covered by the independent claim) as another modification, the protrusion <NUM> may be protrudingly formed on the inner peripheral surface 20a of the side wall part <NUM> near the lower-end opening <NUM> in the configuration of the Modification <NUM>, as shown in <FIG>. According to this Modification <NUM>, because the flange portion13 is allowed to abut on the protrusion <NUM>, positioning of the bottom part <NUM> in the standing direction Z can be made easily.

Furthermore, a Modification <NUM> (not covered by the independent claim) may be configured such that a front edge of the flange portion <NUM> in the configuration of the Working Example <NUM> is bent toward the lower side Z1 in the standing direction, as shown in <FIG>. In this Modification <NUM>, the recessed part <NUM> is formed in the flange portion <NUM> on the inner side of its front edge, and welding is performed in the state that the tip surface 13a of the flange portion <NUM> and the lower end surface 21a of the side wall part <NUM> are set on the same plane. It is noted that also in the Modification <NUM>, the protrusion <NUM> may be protrudingly formed in the same manner as in the Modification <NUM> shown in <FIG>.

Still furthermore, in a Modification <NUM> which illustrates the invention claimed, the bottom part <NUM> is formed in a plate-like shape, and is provided with the protruding part <NUM> that protrudes downward Z1 from the bottom part <NUM> in the standing direction to serve as the lower end <NUM> of the bottom part <NUM>, as shown in <FIG>. In the present example, the protruding part <NUM> is formed on the bottom part <NUM> on the inner side of the outer peripheral edge <NUM> along the outer peripheral edge <NUM>. The height of the protruding part <NUM> is not particularly limited, and may be set, for example, within a range of <NUM>-<NUM>. The bottom part <NUM> and the side wall part <NUM> are welded together from below the bottom part <NUM> in an upward direction Z2 in the state that an end face 11a of the outer peripheral edge <NUM> of the bottom part <NUM> is in contact with the inner peripheral surface 20a of the side wall part <NUM>. It is noted that the protruding part <NUM> is not formed over the entire periphery, and is provided at four corners of the bottom part <NUM>.

In the metal case <NUM> of the Modification <NUM>, the lower end <NUM> of the bottom part <NUM> is formed of the protruding part <NUM> that protrudes to the lower side Z1 in the standing direction. Consequently, when the metal case <NUM> is placed on a placing surface, the protruding part <NUM> serving as the lower end <NUM> of the bottom part <NUM> is reliably in contact with the placing surface, and thus the welding portion <NUM> can be surely prevented from abutting on the placing surface, so that placement stability of the metal case <NUM> can be further improved.

As with the Working Example <NUM>, also in accordance with the Working Example <NUM> and the Modifications <NUM> to <NUM>, the metal case <NUM> that is satisfactory in welding workability and can be stably placed on a placing surface can be provided.

In addition, although in the Working Example <NUM>, the bottom part <NUM> and the side wall part <NUM> are prepared separately and are joined together by welding, in place of this configuration, the Working Example <NUM> is configured such that an extended body 1a of a metal case before welded includes the bottom part <NUM> and the side wall part <NUM> that are continuously formed of one metal plate, and one side of the bottom part <NUM> is continuous with the side wall part <NUM> through a bending portion <NUM>, as shown in <FIG>. And, as shown in <FIG>, the bottom part <NUM> is bent at the bending portion <NUM> with the flange portion13 being laid on the side-wall lower end <NUM> of the side wall part <NUM>, and to which a laser beam is applied in a direction as shown by an arrow L, so that the bottom part <NUM> and the side wall part <NUM> are welded to form the welding portion <NUM>, as shown in <FIG>.

As shown in <FIG>, in the metal case <NUM> of the present example, the boundary part <NUM> between the bottom part <NUM> and the side wall part <NUM> includes the welding portion <NUM> and the bending portion <NUM>. The welding portion <NUM> of the boundary portion <NUM> is located on the upper side Z2 in the standing direction than the lower end <NUM> of the bottom part <NUM> is, and thus, the same operational effects as those in Working Examples <NUM> and <NUM> are exhibited.

Claim 1:
A metal case, the metal case is configured to be placed on a placing surface and has a bottom part (<NUM>) composed of a metal plate, and a side wall part (<NUM>) composed of a metal plate that stands from an outer peripheral edge (<NUM>) of the bottom part (<NUM>), wherein
a boundary part (<NUM>) between the bottom part (<NUM>) and the side wall part (<NUM>) includes a welding portion (<NUM>) formed by welding the both parts together,
the welding portion (<NUM>) is exposed on a surface (10a) of the metal case on a lower side in a standing direction of the side wall part (<NUM>),
the bottom part (<NUM>) is formed in a plate-like shape and has a lower end (<NUM>) that is located on a lower side in the standing direction than the welding portion (<NUM>) is, such that, when the metal case is placed on the placing surface, the lower end (<NUM>) of the bottom part (<NUM>) abuts on the placing surface, so that the weld beads of the welding portion (<NUM>) do not contact the placing surface, characterized in that
the bottom part (<NUM>) is provided with a protruding part (<NUM>) that protrudes to the lower side in the standing direction from the bottom part (<NUM>) to serve as the lower end (<NUM>) of the bottom part (<NUM>), wherein the protruding part (<NUM>) is formed on the bottom part (<NUM>) on the inner side of the outer peripheral edge (<NUM>) along the outer peripheral edge (<NUM>),
the protruding part (<NUM>) is provided at four corners of the bottom part (<NUM>) and not formed over the entire periphery.