JPH0287457A - Manufuacture of storage battery jar - Google Patents

Abstract

PURPOSE:To prevent so called core collapsing phenomenon by inserting a bulkhead member between adjoining cores, and injecting thermoplastic resin into a die. CONSTITUTION:A bulkhead member 29 is inserted into a core 23a formed by the male piece 21a of a die 19a. This male piece 21a is placed as mating with a female piece 20a and a bottom plate 22a. Thermoplastic resin 28a is injected into cavity 26a from an opening 24a through a hot runner 25a. This thermoplastic resin 28a shall preferably be the same resin as a one constituting the abovementioned bulkhead member 29, i.e., olefin type thermoplastic resin such as polypropylene. The thermoplastic resin thus injected into the die 19a secondarily is melted fast with the bulkhead member 29, which has been arranged in the die previously, to be consolidated together.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a storage battery case whose interior is divided into 1M compartments by injection molding.

[Prior Art] FIGS. 12 and 13 respectively show perspective views of storage battery cases 1 and 2 to which the present invention can be applied. The storage battery case 1 shown in FIG. 12 and the storage battery case 2 shown in FIG. 13 differ from each other primarily in the arrangement of the compartments.

The battery case 1 shown in FIG. 12 has a bottom wall (not shown).
and multiple side walls 3.4. 5. 6 and an outer container part 7 is formed. The container portions 7 are arranged in a row.
For example, 6 compartments 8. ...and therefore,
For example, five partition walls 9. parallel to each other. ... is formed.

On the other hand, in the case 1152 shown in FIG. 13, an outer container portion 15 is formed by a bottom wall 1° (FIG. 14) and four side walls 11, 12, 13° 14.

The container part 15 has a total of six compartments 16., for example two rows of three compartments. ..., so that, for example, three partition walls 17. ...and these partition walls 17.・
For example, four partition walls 18. extend in a direction perpendicular to .
... is formed.

FIG. 15 shows a mold 19 for injection molding the battery case 1 shown in FIG. 12. To explain with reference to Fig. m12, the mold 19 includes a female mold 20 and a male mold 21.
Further, a bottom plate 22 is disposed on the female mold 20. The female mold 20 provides a wall surface corresponding to the outer surface of the container portion 7 of the battery case 1. Moreover, the male mold 21 is located in the compartment 8. of the battery case 1. A plurality of cores 23. each providing a wall surface corresponding to the inner surface of... ...is formed. Furthermore, the bottom plate 2
2 includes a hot runner 25 having an opening 24 for receiving the molten thermoplastic resin to be injected. The hot runner 25 has, for example, seven gates 2 communicating with a cavity 26 formed by the female mold 20 and the male mold 21.
7 is provided.

[Problems to be solved by the invention] The problems to be solved by this invention are mainly
or related to the dimensions in each part of 2.

In a type of storage battery container 1, as shown in FIG. 12, the widthwise dimension W of the compartment 8 is approximately 20 to 50 mm, and the height dimension of the battery container 1 is approximately 140 to 200 mm.

Further, the wall thickness of the partition wall 9 is approximately 0.8 to 1 at its upper end.
．． 2mm and about 1.2-2.5m at its lower end
It is m. Note that the reason why the partition wall 9 is tapered as shown in the above-mentioned dimensions is to enable mold release after injection molding.

As can be seen from the dimensions described above, the compartment 8 of the battery case 1
Although its thickness direction dimension W is small, its height direction dimension is large. Further, the wall thickness of the partition wall 9 is also relatively thin. For these reasons, each of the cores 23 formed by the male die 21 shown in FIG.
The space between them becomes narrower.

Therefore, as shown in FIG. 16, when the molten thermoplastic resin 28 is injected into the cavity 26 via the hot runner 25, the injection pressure causes the core 23 to wobble or tilt, a phenomenon called "core collapse". This phenomenon is alive and well.

In FIG. 16, for example, in the part indicated by "A",
Undercuts occur, making demolding impossible after the thermoplastic resin 28 has solidified. On the other hand, in the part marked "B",
The spacing between the cores 23 becomes extremely narrow, and the thermoplastic resin 28
becomes difficult to flow. Therefore, the wall thickness of a part of the partition wall 9 of the battery case 1 obtained by injection molding becomes extremely thin, or a hole occurs in a part.

In order to prevent the above-mentioned defects in the partition wall 9, it is necessary to design the partition wall 9! It is possible to increase the thickness of J and 9. However, if such measures are taken as = 14, the internal volume of the compartment 8 will become smaller or the external dimensions of the battery case 1 will increase, and at the same time, the weight of the battery case 1 will increase. It also has the disadvantage of increasing.

By the way, even in conventional injection molding machines, measures are taken to prevent "core collapse" as much as possible. That is, as shown in FIGS. 15 and 16, a plurality of gates 27 are provided, and each gate 2
7 is located at a position corresponding to the gap between the cores 23. This ensures that the injection pressure is applied as evenly as possible to both sides of each core 23. However, in reality, various factors are added and such countermeasures alone are not sufficient.

As a technique for advantageously preventing the above-mentioned "core collapse", there is a technique described, for example, in Japanese Patent Publication No. 50-2621. In the technique described in this publication, the free end of the core is fixed with a movable pin. Then, while the resin is being injected into the mold, but before the resin has hardened, the movable pin is moved away from the core a distance such that it is flush with the rest of the fixed mold member of the mold. .

Thereby, the subsequently injected resin is caused to fill the hole left by the movable pin.

However, the conventional technology described in this publication requires the use of a mold with a complicated structure and also requires a device to properly control the timing of moving the movable pin, resulting in the cost of molding equipment. There is a problem of inviting up.

The problem that occurs when injection molding the battery case 1 shown in FIG. 12 is that the battery case 2 shown in FIGS.
In the case of injection molding, similar problems are encountered, or in some cases, such problems become more pronounced.

As shown in FIG. 14, some of the battery cases 2 shown in FIGS. 13 and 14 have a height dimension of approximately 8.
In some cases, the widthwise dimension W of the compartment 16 is at least 7 mm. Further, the thickness of the partition wall 17 is 0.68 to 1.2 mm at its upper end t1, and 1.2 to 2.5 mm at its lower end t2. Also,
The wall thickness t3 of the side wall 12 (as well as the side walls 11, 13.14) is approximately 1.7 mm. From this dimensional relationship, the core that provides the wall surface corresponding to the inner surface of the compartment 16 is:
It can be seen that the wall thickness is extremely thin considering its height dimension. Also, the distance between the cores and the distance between the core and the female mold becomes extremely small. In particular, the thickness of the core is smaller than that of the core 23 shown in FIG. 15 described above, and "core collapse" is more likely to occur. Therefore, the above-mentioned defects are likely to occur particularly in the partition wall 17.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a method for manufacturing a storage battery case that can prevent the above-mentioned "core collapse" and eliminate the problems caused thereby.

[Means for Solving the Problems] The present invention provides a storage battery cell in which an outer container portion is formed by a bottom wall and a plurality of side walls, and includes at least one partition wall that divides the container portion into a number of compartments. This is a method of manufacturing a tank by injection molding, and is characterized by having the following configuration in order to solve the above-mentioned technical problem.

That is, a mold is prepared that includes a female mold that provides a wall surface that corresponds to the outer surface of the container portion, and a male mold that has a number of cores that provide wall surfaces that correspond to the inner surfaces of the plurality of compartments. a step of preparing a partition member forming at least a portion of the partition wall, at least the surface of which is made of a thermoplastic resin;
The method is characterized in that it includes the step of inserting the partition wall member between the adjacent cores and then injecting a thermoplastic resin into the mold.

[Operations and Effects of the Invention] In the present invention, when a thermoplastic resin is injected into a mold, a partition member prepared in advance is inserted between adjacent cores. Therefore, this partition member functions to maintain the interval to be formed between the cores at a predetermined value or more, and provides the minimum guarantee for the wall thickness of the partition in the completed storage battery case. Therefore, defects such as holes in the partition walls are prevented from occurring.

At the same time, the partition member acts to substantially prevent "core collapse." In particular, when the wall thickness of the partition wall member matches the spacing between adjacent cores, the presence of the partition wall member produces a result similar to that of mechanically fixing multiple cores to each other. It is also possible to completely prevent "core collapse" from occurring.

With the partition member inserted between adjacent cores, thermoplastic resin is injected into the mold. The thermoplastic resin injected in this way is advantageously fused with the partition member whose at least surface is made of thermoplastic resin, and the partition member is integrated with the other parts of the battery case, and at least one part of the partition wall is integrated with the other parts of the battery case. It becomes a state where it constitutes a section. Furthermore, the above-mentioned fusion is
This is particularly advantageous when at least the surface of the partition member is made of an olefinic resin such as polypropylene, while the thermoplastic resin injected into the mold is the same type of olefinic resin.

As described above, according to the present invention, "core collapse" is almost or completely prevented as the core ages, so even if the core formed in the male shape is thin and the length to the free end is long. Although long, injection molding can be carried out without encountering the problems mentioned above. Therefore, the dimensional limitations of the compartments of storage battery containers that can be fumed without problems by injection molding have been expanded. Even large white compartments can be easily obtained by injection molding. Further, the thickness of the partition wall can also be selected at will. In other words, the thickness of the obtained partition wall can be verified by at least 1♡ by the thickness of the partition wall member prepared in advance, so the thickness of the partition wall can be increased to an extent unimaginable using conventional molding techniques. You can also make it thinner. That is, essentially, the partition wall only needs to perform the function of preventing the passage of the electrolyte contained in the partition, and therefore, as long as it can perform this function, the wall thickness of the partition wall can be made thin. . Further, when all of the partition walls are formed by partition members, there is no need to provide the partition walls with a taper to enable mold release, as in the conventional case. From these factors, it is possible to reduce the weight of the storage battery container, and while maintaining the external shape and j method of the storage battery vehicle h'V as before, the content loss of the compartment can be increased, thereby improving the performance of the storage battery. can be improved. Conversely, it is also possible to reduce the external dimensions of the storage battery case while maintaining the internal volume of the compartment as before.

Further, according to the present invention, as described above, "core collapse" is prevented, so there is no need to provide a large number of gates 27, as shown in FIG. It becomes simple and the molding apparatus including such a mold can be downsized.

Moreover, by preventing "core collapse", molding troubles as shown in FIG. 16 do not occur. This eliminates the loss of work interruptions due to molding problems and improves product yield.

Further, a partition member constituting a part of the storage battery case is prepared in advance, and after it is inserted into a mold, the thermal iI5 plastic resin is injection molded only for the remaining part of the storage battery case. Therefore, since the volume of thermoplastic resin injected in such an injection step can be reduced by the volume occupied by the partition member, the injection time and cooling time can be shortened.

Further, for example, the storage battery case 1 shown in FIG.
Although it is obtained by injection molding in one direction, in that case, "sink marks" occur at the intersections of the side walls 4 and 6 and the partition wall 9. This is because the resin injected to form the partition wall 9 contracts when solidified. However, according to the present invention, since at least a portion of the partition wall is formed by a partition member prepared in advance, that is, solidified in advance, little or no "sink mark" occurs. Therefore, the appearance of the storage battery case becomes excellent.

[Description of Embodiment] An embodiment of the present invention is shown in FIGS. 1 to 6. In this embodiment, the storage battery case 1 shown in FIG.
The purpose is to obtain a storage battery case 1a having substantially the same shape as the one shown in FIG. Therefore, in Figures 1 to 6,
Portions corresponding to those shown in FIGS. 12 and 15 are given the same or similar reference numerals, and overlapping explanations will be omitted.

In FIGS. 1 to 4, the partition member 29 prepared in advance is shown in solid lines, and the remainder of the electric tela, which will be formed secondarily by injection molding later, is shown in imaginary lines.

In this embodiment, the two partition members have dimensions and shapes corresponding to the partition wall 9 shown in FIG. Note that the partition member may be prepared to form only a part of the partition wall 9. It is preferable that the partition member 29 is made of an olefin resin such as polypropylene. The partition wall member 29 may be manufactured by injection molding individually or by cutting out from an injection molding or extrusion molded product, and the method is not limited.

Next, these two partition members are inserted between the cores 23a formed by the male die 21a of the mold 19a as shown in FIG. In addition, in FIG. 6, a taper may not be formed in the gap between adjacent cores 23a.

As described above, after the two partition members are inserted between the adjacent cores 23a, the female die 20a, the male die 21a and the bottom plate 22a are combined as shown in FIG. Note that the cavity 26 formed in the mold 19a that is assembled in this way
The shape of a will be apparent from the external shape of the container part 7 shown in FIGS. 1-4.

Next, from the opening 24a shown in FIG.
8a is connected to the cavity 26 via the hot runner 25a.
It is injected into a. The thermoplastic resin 28a used here is preferably the same type of resin as the resin forming the partition wall member 29 (1), that is, an olefin thermoplastic resin such as polypropylene.
The thermoplastic resin secondarily injected into the mold 19a fuses with the partition wall member 29 already placed in the mold and becomes integrated with each other.

In the mold 19a shown in FIG. 6, a gate 27 communicating from the hot runner 25a into the cavity 26a is provided.
Note that only one a is provided.
Should. However, this does not preclude providing a large number of gates as in the conventional case.

A part of the storage battery case 1a obtained in this way is shown in FIG. As shown in FIG. 5, the partition member 29 is joined at its peripheral portion to the container portion 7 of the electric t61a by the injection molding step described above.
In order to improve the reliability of such joining, the partition member 29
A joint portion 30 is formed so as to sandwich the peripheral edge of the joint portion 30 from both sides.

The joint portion 30 is formed simultaneously with the container portion 7 in the secondary molding step described above.

Another embodiment of the invention is shown in FIGS. 7 and 8. Note that FIG. 7 is a view corresponding to the above-mentioned FIG. In FIGS. 7 and 8, elements corresponding to those included in the embodiments described above are given the same reference numerals, and redundant explanations will be omitted.

The embodiment shown in FIGS. 7 and 8 is characterized in that a rib '31 is formed on the partition member 29. In the embodiment shown in FIGS. These ribs 31 are connected to a pole plate (not shown) inserted into the compartment 8.
The function is to perform positioning. Rib 31
is formed simultaneously with the container part 7 and the joint 30 in the step of injecting the thermoplastic resin. Alternatively, there may be a method in which two partition members on which the J gnats 1 are formed in advance are used, and after these are inserted into a mold, the injection step as described above is performed.

Further embodiments of the invention are shown in FIGS. 9 and 10, respectively. These drawings correspond to FIG.

Referring to FIG. 9, the partition member 29 is formed with a circumferential edge portion 32 having a T-shaped cross section.
is formed with a larger thickness direction/j'' method than in the case of FIG. The dimensions can be increased to the maximum extent that does not exceed the protruding height of the ribs 31.

In the embodiment shown in FIG.
It is formed to cover a relatively wide area around the periphery of. This also has the effect of further increasing the reliability of the connection between the partition member 29 and the container portion 7.

In each of the embodiments described above, the joint portion 30 is formed to sandwich the peripheral edge of the partition wall member 29, but such a joint portion 30 is not essential. That is, the partition wall members and the container portion 7 may be joined in such a state that only the end surfaces of the peripheral edges of the two partition wall members are in contact with the inner surface of the container portion 7.

FIG. 11 shows yet another embodiment of the invention. The storage battery container 2a shown here has substantially the same dimensions and shape as the storage battery container 2 shown in FIG. 13. Moreover, FIG. 11 is drawn using the same method as FIG. 1.

To form the partition wall 17 shown in FIG.
4'34 is prepared. This partition member 34 is inserted into a mold as in the embodiment described above, and then thermoplastic resin is injected into the mold. By this, container part 1
5 and the partition wall 18 are formed, and the partition member 34 is in a state joined to the container portion 15 and the partition wall 18.

In this embodiment as well, the peripheral edge of the partition wall member 34 is sandwiched by the joint portion 35 projecting from the inner surface of the container portion 15, thereby increasing the reliability of the joint.

Although this invention has been described above in connection with the illustrated embodiments, several other modifications are possible within the scope of this invention.

For example, although all of the partition members are made of thermoplastic resin, at least the surface thereof may be made of thermoplastic resin. That is, the partition wall portion may be provided with a core material made of an arbitrary material, and the surface thereof may be coated with thermoplastic resin.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a storage battery case 1a to be obtained by implementing an embodiment of the present invention. FIG. 2 is a sectional view taken along the line ■--■ in FIG. 1. FIG. 3 is a top view of the storage battery case 1a shown in FIG. 1. FIG. 4 is a sectional view taken along line TV-IV in FIG. 3. FIG. 5 is an enlarged perspective view of a part of the storage battery case 1a shown in FIG. 1. FIG. 6 is a sectional view showing a mold 19a for obtaining the storage battery tank 1a shown in FIG. FIG. 7 is a perspective view showing a part of the power storage energization # convex obtained by implementing another embodiment of the present invention. Figure 8 shows the 7th
It is a view seen from the arrow ■ direction in the figure. FIGS. 9 and 10 each show still other embodiments of the present invention and are diagrams corresponding to FIG. 8. FIG. 11 is a perspective view showing a storage battery container 2a to be obtained by implementing still another embodiment of the present invention. FIG. 12 is a perspective view showing a conventional storage battery case 1 in which six compartments 8 are arranged in a row. FIG. 13 is a perspective view showing a conventional storage battery case 2 including a total of six compartments 16 arranged in two rows. Figure 14 shows the line XIV-XI in Figure 13.
It is a sectional view along V. FIG. 15 is a sectional view showing a mold 19 for obtaining the storage battery case 1 shown in FIG. 12 by injection molding. FIG. 16 is a diagram corresponding to FIG. 15, and is a sectional view showing a "core collapse" state as a problem to be solved by the present invention. In the figure, la and 2a are storage battery containers, 3,4°5.6
, 11, 12, 13.14 are side walls, 715 is a container portion, 8.16 is a compartment, 9. 17. 18 is a partition wall, 10 is a bottom wall, 19a is a mold, 20a is a female mold, 21a is a male mold,
23a is a core, 29 and 34 are partition members, and 30.35 is a joint portion. Figure 1 Diagram

Claims (1)

Claims: A storage battery case is produced by injection molding, the outer container part being formed by a bottom wall and a plurality of side walls, and comprising at least one partition dividing the container part into a plurality of compartments. a female mold providing a wall surface corresponding to the outer surface of the container portion;
and a male mold having a plurality of cores each providing a wall surface corresponding to an inner surface of the plurality of partitions, the mold forming at least a part of the partition wall, and at least the surface thereof. The method is characterized by comprising steps of preparing a partition member made of thermoplastic resin, inserting the partition member between the adjacent cores, and then injecting the thermoplastic resin into the mold. , a method for manufacturing a storage battery container.