JPH057998A - Mold for continuously casting lead battery grid body - Google Patents

Abstract

PURPOSE:To provide a grid body having a little residual blow hole by using the specific porous material. CONSTITUTION:In a continuous casting apparatus for lead battery grid body, a continuous casting mold for lead battery grid body composed of porous material 8 having engraving part 2 for forming the grid body on the outer peripheral part of a drum and having structure for supplying a liquid parting agent such as oil onto the surface of the periphery surface from inner part of the drum through the porous material 8, is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for continuous casting of a lead-acid battery lattice body which supplies an inexpensive and stable lattice body.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a method for producing a lattice by continuous casting. That is, the engraving 2 formed on the circumferential surface of the rotating drum 1 is attached to the hot water supply unit 4
The melt 3 of the lead alloy supplied via the drum is solidified between the belt 5 which comes into contact with a part of the drum and rotates integrally with the drum, and the drum, thereby forming a lattice body 6 connected in a belt shape. It is to be peeled from the surface.

Generally, in the case of die casting, a mold having a draft is set in order to facilitate the release of the casting, but in the case of the above lattice, the strength of the casting is small,
In order to further facilitate mold release, a mold release agent (generally oil such as peanut oil) is applied to the drum surface. Japanese Unexamined Patent Publication No. 59-76846 discloses a method of spraying oil onto the drum surface (inner surface of the engraved portion) with the spray 7.

Further, in order to keep the circumferential surface of the drum at a desired temperature, a cooling medium (not shown) is passed through the inside, but the circumferential surface has a desired temperature. In a state in which it becomes higher than the above, the same as in JP-A-59-59
As shown in JP-A-76846, a water supply spray 14 for spraying water on the drum surface is used as auxiliary cooling.

[0005]

As mentioned above, since the strength of the lattice is small, it is essential to use oil for facilitating the mold release. However, the oil is decomposed and vaporized at the time of casting, and the oil remains in the molten metal. It is taken in and remains as bubbles inside the lattice due to solidification. This bubble is called a blow hole. Figure 3
[Fig. 4] is an enlarged schematic view of a cross section of the lattice body, showing a situation in which a large number of blow holes 12 are present. If blowholes are present in the grid, corrosion resistance to the electrolytic solution is poor when used in a lead storage battery, which poses a serious problem in practical use. In order to prevent the above-mentioned blowholes from remaining inside the lattice, it is desirable that oil is not used or that the amount of oil is very small. However, as described above, the use of oil is indispensable, and it is a very important technique to supply an extremely small amount of oil in order to suppress the generation of blowholes to the extent that there is no practical problem.

Further, in the case of supplying water for controlling the temperature of the drum surface as described above, it can be denied that there is a possibility of causing blowholes as in the case of supplying oil, although it easily evaporates. Absent.

From this point of view, the conventional method of supplying oil by spraying and the method of cooling the drum surface with water are not preferable.

[0008]

[Means for Solving the Problems] In order to prevent blowholes due to the decomposition and vaporization of oil from remaining inside the lattice, it is necessary to quantitatively supply a very small amount of oil. In the present invention, instead of supplying oil from the outside of the drum as in the conventional case,
It is a structure in which a part of the drum is made of a material having appropriate fine holes and oil is supplied from the inside of the drum through the fine holes so that a very small amount of oil can be quantitatively supplied in the engraving. The structure will be described with reference to FIG. That is, the surface side of the drum 1 is formed of the porous material 8. The part 8
Is communicated between the hole 9 and the surface of the drum 1. And the engraving 2 for forming the lattice body is the porous material 8
To form. The oil used as the release agent flows in from the oil-sealed rotating shaft 11, passes through the hollow spokes 10, and flows into the holes 9. The inflowing oil passes through this part and spokes 1
0 ', is discharged via the rotating shaft 11. At this time, the oil filling the pores 9 is supplied to the surface of the porous material 8 through the continuous pores. The amount of oil supplied to the outer peripheral surface of the drum is determined by appropriately adjusting the amount of oil flowing from the rotary shaft 11 and the amount of oil discharged from the portion 11. With the above method, it becomes possible to supply a very small amount of oil to the outer peripheral surface of the drum.

On the other hand, in general, since the molten metal having a temperature of about 500 ° C. is continuously supplied to the drum, if left unattended, the drum reaches a temperature at which the molten metal does not solidify between the belt and the drum. . Therefore the drum must be cooled by some means. Usually, a cooling medium is introduced into the drum to cool it, but it may be necessary to further spray water on the drum surface to cool the portion. In this case, needless to say, this is due to incomplete cooling of the drum with the cooling medium. Oil is usually used as the cooling medium. Needless to say, in order to improve the cooling efficiency, the oil should be made to flow as close as possible to the engraving, and the contact area between the oil and the drum should be as large as possible and the oil should be at an appropriate speed. It is necessary to flush it with. However, flowing the oil as close as possible to the engraving may cause a problem in terms of strength because the thickness of the drum becomes small. Even if the flow velocity of oil is sufficiently high, the heat exchange between the drum and the cooling medium is determined by the heat transfer coefficient between them, and cannot be increased infinitely. Therefore, the second aspect of the invention takes such a matter into consideration.

Conventionally, as described above, the cooling of the drum by the cooling medium is performed by introducing the cooling medium into the drum, exchanging heat between the drums, and then discharging the drum, and then discharging the drum by an appropriate means. In this method, the medium is cooled and then introduced again into the drum. That is, the cooling medium exists in the closed system, and the cooling medium whose temperature has risen must be cooled only outside the drum.

On the other hand, in the mold according to the second aspect, the method of cooling the cooling medium whose temperature has risen is basically the same, but the cooling medium, that is, oil, on the outer peripheral surface of the drum is further added. It has the advantage that the heat balance associated with decomposition and vaporization can be used additionally.

Further, the mold according to claim 3 promotes heat exchange between the cooling medium and the drum by increasing the contact area between them. This will be described with reference to FIG. In the figure, the porous material 8'has an appropriately large hole diameter in order to increase the contact area between the cooling medium and the drum as much as possible and to allow the cooling medium to flow at an appropriate speed. However, since engraving such a portion and injecting the molten metal may cause the molten metal to enter the hole, the porous material 8 having an appropriately small hole diameter is arranged on the outside of this. Further, from the problem of supplying a very small amount of releasing oil, it is necessary that the pore diameter of the porous material 8 on the left is appropriately small.

The reason why the non-engraved surface of the porous material 8 according to claim 4 is closed is as follows. The oil, which is supplied in a very small amount, is discharged to the drum surface by the porous material 8, but the purpose can be achieved if the oil exists only in the engraving 2 for releasing the lattice. In other words, the oil discharged from the non-engraved surface may adhere to the belt surface and the lower part of the hot water supply portion that contacts the drum without being used, and may cause blow holes. Further, the frictional force with the belt is reduced, which prevents the both from rotating together. For the above reasons, the non-engraved surface of the porous layer 8 is closed by the closing layer 13 as a structure in which oil is not supplied to other than the engraved portion.

[0014]

By using the continuous casting mold having the above-mentioned structure, it is possible to easily release the grid body from the drum, and it is possible to manufacture the grid body without blowholes. It is possible to supply a highly reliable lead acid battery.

[0015]

EXAMPLES Next, examples of the present invention will be described. Figure 1
The structure of the mold for continuous casting of the lead storage battery grid of the present invention is shown in FIG. The outer diameter of the drum is 300mm, the width is 145mm, and the thickness is 5
It is 0 mm. The material of the drum is FCD35, and the porous material 8
Is a sintered body containing iron as a main component and has a thickness of 5.0 mm. The diameter of the holes in the porous material 8 is 0.010 mm on average and 1 cm.
The number of holes per ² is about 8000. The engraving 2 machined on the portion 8 has a thickness of 0.8 mm to 1.2.
The engraved cross-sectional area in mm is 0.49 mm ^{2 to} 2.00 mm ² , and the shape is such that the lattice can be separated from the drum surface. Using the mold having the structure shown on the left, a lattice was cast at a melt temperature of 480 ° C., a mold temperature of 130 ° C., and a mold rotation speed of 30 rpm. The amount of oil supplied to the drum surface at this time was adjusted so as to be 4 g / min. At the same time, the drum temperature was adjusted to 13 g as described above.
The temperature could be adjusted to 0 ° C. FIG. 4 shows a cross-sectional photograph of the produced grating body, and Table 1 shows the results of examining the occurrence of blowholes for 100 lattices according to the present invention.

[0016]

[Table 1]

The blowholes are shown divided into those having a diameter of less than 0.5 mm and those having a diameter of 0.5 mm or more. However, in the conventional method, the blowholes were present in more than half of the observed lattices. In contrast, according to the present invention, blowholes with a diameter of 0.5 mm or more are not recognized, and
Even if it was less than mm, the occurrence rate of blowholes was as small as 3%.

FIG. 5 shows the structure of the cross section of the drum shown in claim 3. The outer diameter, width and thickness of the drum are almost the same as in the above embodiment. The material of the drum body is FCD35,
Porous material 8'has a communication hole with an average pore diameter of 0.81 mm of 1 cm ²
It is an iron-based alloy with 21.6 pieces per piece, and its width is 135
mm, the thickness is 10 mm. A powder containing chromium as a main component was plasma sprayed on the portion 8'to form a porous material 8 having a thickness of 1.5 mm. The number of holes in the porous material 8 is 1190
It is about 0. The engraving and casting conditions applied to the portion 8 by machining were almost the same as those in the above-mentioned embodiment. The evaluation results are shown in Table 1 as the present invention. As in the above-mentioned present invention, no blowhole with a diameter of 0.5 mm or more is recognized,
Even if the thickness was less than 0.5 mm, the occurrence rate of blowholes was as small as 4%. Also, the temperature of the drum could be set to a desired temperature.

Further, as shown in FIG. 4, the surface of the porous material 8 of the drum is closed by performing chromium plating of 0.03 mm to 0.05 mm on the mold of FIG. 5 as shown in FIG. did. The casting conditions and the like of the lattice are almost the same as those in the above embodiment. The present invention is shown in Table 1 as a result of carrying out with the number of specimens 500 for the condition of blowhole generation. In this case, the occurrence of blowholes was extremely reduced.

[0020]

As is apparent from FIG. 3 and Table 1, by using the continuous casting mold for the lead-acid battery grid of the present invention, it is possible to supply a lead-acid battery that is inexpensive and highly reliable.

[Brief description of drawings]

FIG. 1 is a view for explaining a continuous casting mold for a lead storage battery grid according to the present invention, in which (a) is a front view and (b) is an AA cross-sectional view of (a).

FIG. 2 is a mold for continuous casting of a conventional lead storage battery grid,
(A) is a front view and (b) is a side view.

FIG. 3 is a schematic cross-sectional view of a grid body manufactured using a mold for continuously casting a lead storage battery grid body.

FIG. 4 is a schematic cross-sectional view of a grid body manufactured by using the mold for continuous casting of the lead storage battery grid body of the present invention.

FIG. 5 is a partially enlarged view of a mold for continuous casting of a lead storage battery grid according to the present invention.

FIG. 6 is a partially enlarged view of a mold for continuous casting of a lead storage battery grid according to the present invention.

[Explanation of symbols]

1 is a drum, 2 is engraving, 3 is a molten metal, 4 is a hot water supply part, 5 is a belt, 6 is a lattice, 7 is an oil supply molten spray, and 8 '
Is a porous material, 9 is a hole, 10 is a spoke, 11 is a rotating shaft, 12 is a blow hole, 13 is a blocking layer, and 14 is a water supply spray.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Doen Toritoku             832 Horiguchi, Katsuta City, Ibaraki Prefecture 2nd Co., Ltd.             Hitachi Research Laboratory, Hitachi Ltd.

Claims (4)

[Claims] 1. A casting apparatus for forming a lattice by continuously supplying a molten metal to the engraving of the surface of a rotating cylindrical mold (drum) and solidifying the molten metal, which is used for the engraving. The formed portion is made of a porous material, and a liquid type release agent such as oil is supplied to the outer peripheral surface from the inside of the mold through the porous material to the outer peripheral surface of the lead storage battery grid. Continuous casting mold. 2. The continuous casting mold according to claim 1, wherein the cooling medium used for controlling the temperature of the mold also serves as a release agent. 3. The continuous casting mold according to claim 1, wherein the portion made of a porous material is made of a plurality of porous materials having different porosities and materials. 4. The continuous casting mold according to claim 1, wherein a portion of the outer peripheral surface other than the engraving is treated to prevent the release agent from being supplied.