JPH11123503A - Apparatus for continuously casting grid body of lead battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb the expansion and the shrinkage of a drum surface caused by casting heat cycle and to inhibit cracking on the peripheral surface of the rotary drum by arranging a buffering mechanism (knurled part) to the heat expansion/ shrinkage of a peripheral surface on the peripheral surface of the rotary drum for casting a grid body of a battery. SOLUTION: Plural crossed grooves for buffering the heat shock (knurled part) 5 are arranged on a part except the scriptions 2 of groove parts for forming the casting on the peripheral surface 1a at both side parts of the rotary drum 1. Then, the cross section of the knurled part 5 is formed in a reversed trapezoidal shape, in which the groove width becomes narrower toward the outer peripheral surface of the drum, and the interval between the grooves is made to the interval which can sufficiently absorb even if the peripheral surface 1a of the drum is repeated to expand and shrink caused by the heat cycle. Concretely, in the case of the drum 1 having 413 mm outer diameter, 420 mm width and FCD400 material, the pitch, depth and width of the groove for buffering the heat shock are made to 10 mm, 1.5 mm and 1.2 mm, respectively, and the angle of the groove side wall to the groove bottom surface, is made to 70 deg. to form the groove width narrower toward the outer peripheral surface of the drum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously casting a grid structure of a lead-acid battery.

[0002]

2. Description of the Related Art A grid of lead-acid battery plates for automobiles has long been produced using a so-called book mold type casting machine. In this method, a molten lead alloy is cast into a mold consisting of two cast iron blocks having a depth of engraving half the thickness of the grid. In this book mold type casting machine, although the degree of freedom of the engraving shape, that is, the design of the lattice is higher than that of the expanding system described later, the productivity is not necessarily good because it is a batch type production system. Therefore, development of a grid production method with higher productivity was attempted, and the expand method was put into practical use about 15 years ago. According to this method, the production process of the electrode plate is continuously performed from the production of the grid to the filling and drying of the power generation material, and a significant improvement in the quality of the electrode plate as well as the productivity can be expected. However, the expanding method also has a major drawback. That is, the degree of freedom of the lattice design is significantly smaller than that of the casting method. This is a major problem for lead-acid batteries for automobiles, for which there is a remarkable demand for higher performance, but is extremely difficult to solve because it is due to the essence of the expanding process. Therefore,
In recent years, a continuous casting method has been proposed as a method of producing a lattice with a high degree of freedom in lattice design and good productivity.
It is disclosed, for example, in U.S. Pat. No. 4,534,404. As shown in the front view and the side view of FIG. 2, the battery grid body continuous casting apparatus here has a cylindrical mold (hereinafter, referred to as a cylindrical mold) in which a plurality of grid body forming engravings 2 are provided continuously on a circumferential surface 1 a in a circumferential direction. , A drum), a molten metal is continuously supplied to these lattice-shaped engraving 2 from a nozzle 3 that slides on the peripheral surface of the mold, and a molten metal (hereinafter, referred to as “metal”) in the lattice-shaped engraved 2 is formed. The molten metal (abbreviated as molten metal) is solidified so that the lattice body 4 is continuously drawn on the belt and continuously cast. In such a continuous casting method, for example, the grid body 4 can be produced at a casting speed of about 30 m / min, and the productivity is about the same as that of the expanding method.

[0003] By the way, in producing the lattice body 4,
The material of the drum 1 is the same cast iron as the material of the mold by the book mold method described above. The use of cast iron as the material of the mold is because graphite is present in the material structure, and this graphite suppresses the wetting with the molten metal and facilitates the release of the lattice.

[0004]

However, the conventional casting method using the conventional mold for continuous casting of a battery grid has the following problems. In the continuous casting method, as described above, a molten metal is continuously supplied from a nozzle 3 to a drum 1 on which a plurality of grid body forming engravings 2 are continuously provided in a circumferential direction, and the molten metal is solidified. Since the drum 4 is produced, the drum 1 is subjected to a heat cycle (thermal shock) in one rotation cycle. As a result, in particular, the peripheral surface 1a of the drum 1 repeats expansion and contraction due to the heat cycle, and the buffer of the stress at that time must be absorbed by the grain boundaries of the cast iron structure, and as a result, cracks are formed along the grain boundaries on the left Will happen. Since this relates to the life of the drum 1, an increase in cost such as the production cost cannot be ignored. The problem to be solved by the present invention is
It is an object of the present invention to provide a continuous storage device for a lead-acid battery lattice, which does not easily crack on the drum peripheral surface 1a even when subjected to a heat cycle.

[0005]

In order to solve the above-mentioned problem, a lead-acid battery grid continuous casting apparatus according to the present invention is characterized in that the drum peripheral surface 1a is provided with a buffer mechanism for thermal expansion and contraction of the peripheral surface. And Specific examples of the thermal expansion / contraction buffer mechanism include:
It is composed of a plurality of intersecting thermal shock buffering grooves (hereinafter referred to as knurls) arranged on the drum peripheral surface 1a other than the casting forming engraved two groove portions, and the groove width in the cross-sectional shape of the knurl 5 is directed toward the drum peripheral surface 1a. This is a configuration that becomes narrower according to the following. In the present invention, a plurality of intersecting knurls 5
A groove portion formed in the sliding portion of the peripheral surface 1a with the nozzle 3 other than the lattice-shaped engraving 2 and particularly in a portion where the bone-engraved engraving in the lattice is not performed. This absorbs the expansion and contraction of the drum surface. In this case, it is important that the pitch of each knurl 5 is set to an interval that can sufficiently absorb the heat cycle of the peripheral surface 1a of the drum 1 even if the peripheral surface 1a repeatedly expands and contracts. Although it depends on the size of the grains, it is preferably 10 mm or less. In addition, the cross-sectional shape of the knurl 5 needs to be such that the molten metal is supplied to the portion and solidified so as not to be released from the surface of the drum 1 as a casting. This is because when the mold is released as a casting, the casting must be separated and removed from the lattice body by some means. From this point of view, it is necessary that the groove width in the cross-sectional shape of the knurl 5 be narrowed toward the drum peripheral surface 1a. The lead that has entered the knurl 5 groove,
When the drum 1 is heated to a high temperature, it becomes a molten metal and flows, so that it does not hinder the buffering action when the drum thermally expands and contracts. As described above, by providing a plurality of intersecting knurls on the sliding surface of the rotary drum with the nozzle, even when subjected to a heat cycle, cracks are less likely to occur on the drum peripheral surface 1a. A lead-acid battery grid can be provided.

[0006]

FIG. 1 shows an example of a drum 1 according to the present invention. In the case of this example, the outer diameter of the rotary drum 1 is 413 mm, the width is 420 mm, and the material is FCD400.
It is. The nozzle has a width that covers two widths of the engraving. FIG. 4 is a sectional view of the knurl 5. As shown in FIG. 4, the groove pitch, depth, and groove width of the peripheral surface 1a of the knurl 5 were 10 mm, 1.5 mm, and 1.2 mm, respectively. Also, the angle between the bottom surface of the groove of the knurl 5 and both side walls is set to 70 °, so that the groove width in the cross-sectional shape of the knurl 5 becomes narrower toward the drum peripheral surface 1a. The knurling method is based on grinding.

In the above example, the buffer mechanism for thermal expansion / contraction of the peripheral surface provided on the drum peripheral surface 1a is realized by knurling the drum peripheral surface 1a, but other means may be used. In the case of realizing a buffering mechanism for thermal expansion and contraction of the peripheral surface by knurling, the dimensions such as the groove pitch and depth of the knurl in the above example are appropriately determined according to the material of the drum used and the size of the crystal grains. Is not particularly limited as long as the design is obtained. Also, the knurling method is not limited.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A continuous lead-acid battery grid casting apparatus using a drum 1 described in the above embodiment of the present invention, and a continuous lead-acid battery grid cast using a drum of the same dimensions and material except that the drum 1 is not knurled. Using a device, they were compared and studied. Pb-1.5% Sb-0.25As-0.02S
A lattice body having the shape shown in FIG. 3 was cast from the e-alloy under the conditions of a melt temperature of 480 ° C., a mold surface temperature of 180 ° C., and a mold rotation speed of 30 m / min. As a result, when a conventional lead-acid battery grid body continuous casting apparatus without knurling was used, cracks occurred on the peripheral surface of the drum in a cumulative operation time of 2400 hours, whereas knurling according to the present invention was performed. In the applied lead storage battery lattice continuous casting apparatus, no crack was generated on the peripheral surface of the drum even when the cumulative operation time was 5000 hours.

[0009]

As described above, according to the present invention, it is possible to provide a lead storage battery grid continuous casting apparatus in which a crack is less likely to occur on the drum peripheral surface even when the drum is subjected to a heat cycle.

[Brief description of the drawings]

FIG. 1 is a view showing a drum for continuous casting of a lead-acid battery grid according to the present invention.

FIG. 2 is a view showing a conventional lead-acid battery grid continuous casting drum.

FIG. 3 is a view showing a grid of a lead-acid battery.

FIG. 4 is a sectional view of a knurl according to the present invention.

[Explanation of symbols]

 1. Drum 1a. Peripheral surface 2. Engraving 3. Nozzle 4. Lattice body 5. Knurl

Continuation of front page (72) Inventor Miaki Machiyama 2-8-7 Nihonbashi Honcho, Chuo-ku, Tokyo Shin-Kobe Electric Machinery Co., Ltd.

Claims (2)

[Claims] 1. A casting is continuously manufactured by continuously supplying molten metal from a nozzle sliding on the peripheral surface of the casting mold to a groove for forming a casting on the peripheral surface of the rotating cylindrical casting mold and then solidifying the molten metal. The continuous casting apparatus for a lead-acid battery grid according to claim 1, wherein a buffer mechanism for thermal expansion and contraction of the peripheral face is provided on the peripheral surface of the mold. 2. A thermal expansion / contraction buffer mechanism comprising a plurality of intersecting thermal shock buffer grooves arranged at portions other than a casting forming engraving groove portion on a peripheral surface of a mold, and a groove in a cross-sectional shape of the thermal shock groove. 2. The continuous casting apparatus according to claim 1, wherein the width becomes narrower toward the peripheral surface of the mold.