JPH0641022B2 - Casting method of grid for lead-acid battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a casting method for a grid for a lead storage battery.

Configuration of Conventional Example and Its Problems As a mold for a lead-acid battery grid, generally, a matching mold is used in which corresponding grid-shaped casting grooves are formed on opposite surfaces of a pair of molds, and both molds are butted and joined together. There is.
FIG. 1 shows one of the pair of molds. In the drawing, 1 is a mold mating surface, 2 is a vertical lattice groove, 3 is a horizontal lattice groove, 4 is a frame bone groove, 5 is a casting groove for an ear portion, and is hereinafter referred to as an ear portion forming groove. Casting uses a casting mold made of an appropriate material such as cast iron, and after closing the fixed mold and the movable mold, the molten lead or lead alloy (hereinafter referred to as hot water) from the pouring port provided in the mold. ) Is poured, and this is cooled and solidified, then the mold is opened and the product lattice is taken out. In this case, the frame bone,
Both the horizontal lattice and the vertical lattice are thin and relatively cool and solidify.

However, the ears of the lattice generally have a rectangular shape, and the volume thereof is much larger than that of the horizontal and vertical lattices, and a large amount of hot water is poured. Therefore, just applying a mold-coating agent such as ordinary cork powder does not promote the cooling and solidification uniformly, and it may occur near the boundary line between the frame bones connecting the horizontal and vertical lattices and the ear part (hereinafter referred to as the boundary part), Heat remained near the center of the ears, causing cracks and defects called burns, and the strength of those parts significantly decreased and became brittle, causing breakage of the ears. On the other hand, in order to improve this problem, as shown in FIG. 2, a protrusion 6 is formed in a strip shape in the central portion along the length direction of the ear forming groove, and a coating agent is applied to the protrusion 6. A casting method has been proposed in which the heat remaining in the vicinity of the center of the ears is quickly radiated by casting without the use of the ears to prevent cracks and burns in the ears. By this casting method, the cracks and burns that occur near the center of the ear were significantly reduced and the castability was improved. However, in the boundary portion 7, in order to improve the castability of the ears, the strength of the physical properties, and the voltage characteristics of the battery, an arc having a large radius and a grading of the thickness connected to the frame bone are made. The boundary portion is a portion where a frame bone having a larger cross-sectional area than the horizontal and vertical lattices and an ear portion having a significantly large cross-sectional area are in contact with each other.
Therefore, the boundary has an extremely large volume, and cooling is delayed compared to the parts other than the boundary at the protrusions that are provided almost uniformly, cracks due to residual heat, strength decrease due to burns, and eventually breakage at the boundary. It was

OBJECT OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and an object of the present invention is to efficiently produce a high-quality lattice.

Configuration of the invention, the casting method of the lattice body in the present invention, among the casting grooves for casting the lattice body having a rectangular ear casting groove, the ear casting groove is a frame bone groove at the joint with the frame bone groove. Has a circular arc or an inclined portion that widens toward the inside, and the inside of the groove is provided with a protrusion whose cross-sectional area changes in direct proportion to the change in the cross-sectional area in the longitudinal direction of the groove. While being coated, the surface of the protrusion is cast without applying a coating agent. According to this casting method, even in the portion where the width or depth of the groove for forming the ear portion is larger than that of the other portion, the cross-sectional area increases, and the cooling is delayed when pouring the molten metal, the cross-sectional area of the protrusion increases to allow release. The amount of heat is large and the cooling proceeds at a uniform speed over the entire grid including the ears. Therefore, it is possible to efficiently produce a high-quality lattice without cracks or burns due to residual heat.

Further, since the circular arc or the inclined portion that spreads from the ear casting groove toward the frame bone groove is provided, the ear casting property, the ear strength, and the battery voltage characteristic can be improved.

Description of Examples One example of the casting method of the present invention will be described below. FIG. 3 shows the ear portion forming portion of the mold used in the casting method of the present invention. In this figure, the protrusion 6'has an arc near the boundary in accordance with the arcing at the boundary of the ear forming groove, and the width W _{2 of the} ear forming groove is
On the other hand, the width W ₁ of the protrusion is almost 2 at any position of the ear.
3%.

FIG. 4 shows a cross section of the casting groove taken along the line AA ′ shown in FIG. Before pouring hot water, the mold is heated in advance to 160 to 200 ° C., and a coating material 8 such as cork is applied as shown in FIG. Only the coating agent on the portion 6'is scraped off as shown in FIG. After that, hot water is poured into a mold space formed by abutting both molds. Immediately after pouring, cooling of the molten metal starts in the mold, but the heat of the molten metal is more easily absorbed by the mold body from the exposed protrusions 6'of the mold, and the cross-sectional area of the protrusions 6'increases the boundary. The cooling rapidly progresses even in the parts, and not only the ears but also the entire lattice is uniformly and quickly cooled and solidified at the same speed. Therefore, cracks and burns do not occur, and a high-quality grid body can be efficiently obtained.

There is also the step of putting the ears of the grid into the comb-shaped jig when creating the finished plate group of the grid into the plates, but with the purpose of sharing this comb-shaped jig. Another method is to change the thickness of a part of the other to match the thickness of the other ear of the lattice. In this case, the cross-sectional area changes due to the change in the depth in the ears forming groove of the mold, but by changing the cross-sectional area due to the change in the height of the protrusion, similarly, a high-quality lattice can be obtained efficiently. be able to.

FIG. 7 shows the change in the width of the protrusion with respect to the width of the ear forming groove in a mold in which the depth of the ear forming groove and the width of the protrusion are constant, and the occurrence rate of lattice defects due to cracks and burns in the ear. And the effect on castability. As is clear from the figure, as the width of the protrusion increases with respect to the groove for forming the ear, the defect occurrence rate sharply decreases, and the ratio of width is 20% and the defect rate is 30% or less. 20
%, The defect rate gradually decreases, but the castability decreases gradually, and when the width ratio is 40% or more, the castability decreases remarkably. Therefore, the width of the protrusion with respect to the ear forming groove is 20 to
40% is suitable. FIG. 8 shows the influence of the change in the cross-sectional area in the longitudinal direction of the protrusion with respect to the cross-sectional area in the longitudinal direction of the groove for forming the ears on the occurrence rate of lattice defects due to cracks and burns at the ears and castability. This change in the cross-sectional area also shows the same tendency as in the case of the width, and for the same reason, the cross-sectional area of the protrusion with respect to the ear forming groove is preferably 1.5 to 3.5%.

EFFECTS OF THE INVENTION As described above, according to the casting method of the present invention, not only the ear portion but the entire lattice is improved while improving the castability of the ear portion, the strength of the joint portion between the ear portion and the lattice frame bone, and the characteristic of the battery voltage. It is possible to uniformly and promptly cool and solidify over a long period of time, and it is possible to efficiently obtain a good and high-quality grid body for a composition that is free from cracks and burns due to heating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing one of a pair of molds used in a conventional casting method, FIG. 2 is an enlarged view of a part of a casting groove, and FIG. FIG. 4 is an enlarged view of the main part of the casting groove of the mold used in the embodiment of FIG. 4, FIG. 4 is a sectional view taken along the line AA ′ of FIG.
The figure shows a cross-sectional view of the mold mating surface coated with a coating agent, No. 6
FIG. 7 is a cross-sectional view in which the coating agent is scraped off from the protrusion, and FIG. 7 is a characteristic diagram showing the relationship between the ratio of the width of the protrusion to the width of the casting groove for the ear, the lattice defect rate, and the castability. FIG. 4 is a characteristic diagram showing the relationship between the ratio of the cross-sectional area of the protrusion to the cross-sectional area of the casting groove for the ear, the lattice defect rate, and the castability. 1 ... Mold matching surface, 2 ... Vertical lattice groove, 3 ... Horizontal lattice groove, 4 ... Frame bone groove, 5 ... Ear casting groove, 6 ... Projection, 7
…… Boundary area, 8 …… Coating agent.

Front page continued (72) Inventor Shigeki Matsuzawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References Japanese Patent Publication No. 56-50657 (JP, B1) Japanese Patent Publication No. 56-46469 (JP, B1)

Claims (3)

[Claims] 1. A pair of casting molds is provided with a casting groove for casting a lattice body, which is provided with a rectangular casting groove for an ear portion, and the casting groove for an ear portion is a frame bone groove at a joint portion with a frame bone groove. It has a circular arc or an inclined portion that widens toward the inside, and the inside of the groove is provided with a protrusion whose cross-sectional area changes in direct proportion to the change in the cross-sectional area in the length direction of the groove. On the other hand, a method for casting a lead battery grid body characterized by injecting molten lead or a lead alloy into a mold space formed by abutting both molds in a state in which no mold coating agent is applied to the surface of the protrusion. . 2. The ratio of the width of the protrusion to the width of the selvage casting groove is
20-40%, The casting method of the grid body for lead acid batteries according to claim 1. 3. The ratio of the cross-sectional area in the lengthwise direction of the protrusion to the cross-sectional area in the lengthwise direction of the selvage casting groove is 1.5 to 3.5%. Casting method of grid for lead-acid battery.