Automotive brake piston die-casting movable insert mold structure

Abstract

The present invention relates to a die-casting movable insert mold structure for an automobile brake piston, comprising a fixed core (10); A movable core (20) located at the rear of the fixed core (10); It is composed of a movable insert core (30), which is an inner core inserted and coupled into the central hole of the above-mentioned movable core (20); when the movable core (20) with the movable insert core (30) coupled to the rear of the fixed core (10) at the start of die casting, molten metal is injected, and after the die casting is finished, the movable core with the movable insert core coupled to it retracts, and the product piston is removed from the mold. Forming three insert overflows (31, 32, 33) for gas discharge in the shape of the above-mentioned movable insert core (30) is for gas discharge, and The three insert overflow areas (31, 32, 33) are areas where gas is prone to becoming isolated during the final stage of filling, so they are formed adjacently, but are configured to be separated so that gas can escape from each one. From the movable insert core in-gate (21) into the product space, the first insert overflow 1 (31) in the molten metal flow direction is filled with 7 to 15% of the molten metal injection weight, the central insert overflow 2 (32) is filled with 4 to 6%, and the last insert overflow section 3 (33) is filled with 3 to 5%, and an overflow pipe (23) is formed outside the product space. Offflow 1 is a concave groove with a fan-shaped cross section, and Offflow 2 is a concave groove with a rectangular cross section; Offflow is formed to be longer in the radial direction than Offflow 1 and 2, and has a cross-sectional shape in which the width decreases due to a step formed in the middle, and the front end has a beveled surface on one side and a straight line on the opposite side, while the rear end has a shape in which both sides are straight lines. The molten metal is configured to fill the end portion (1) formed in the runner before flowing into the product space, and if the solidified end portion (1) after casting is not completely filled, it is treated as a defect due to insufficient molten metal, and the end portion (1) is curled. The molten metal ratio is such that molten metal is injected in an amount of 380 to 381 parts by weight for the runner and 139 to 140 parts by weight for the overflow, relative to 529 to 530 parts by weight for the piston, which is the product. The cooling pipes are arranged to allow for a bidirectional cooling flow. On one side of the mold, the piping is installed so that a horizontal pipe bends at a right angle to be drawn in, then returns to a vertical pipe and becomes a horizontal pipe for drainage. On the other side, cooling water pipes are installed in a concentric, small ring shape to match the circular shape of the piston. These pipes are connected horizontally to both sides of the circular cooling water pipes, allowing the cooling water to be drawn in, circulate through the ring shape, and then discharged, thereby uniformly cooling the molten metal inside the mold. Alternatively, instead of a ring-shaped cooling water pipe, a C-type open shape is formed, with an inlet pipe and an outlet pipe connected to each open part, and five spot cooling sections (43) are installed on the opposite side of the open part, so that the part with the slowest solidification is uniformly cooled by the spot cooling section (43) and the open ring section (44) with other parts. In the die-casting process using an automobile brake piston operating insert mold, the gas exhaust hole and vacuum design are optimized to reduce bubbles, erosion, and defects, thereby improving quality and lowering production costs, resulting in a significant economic effect.

Description

Technology Field

[0001] The present invention relates to a die-casting movable insert mold structure for automobile brake pistons, and more specifically, to an economical die-casting movable insert mold structure for automobile brake pistons that improves quality and lowers production costs by optimizing the gas exhaust hole and vacuum design in a die-casting process using the movable insert mold for automobile brake pistons, thereby reducing bubbles, erosion, and defects. Background Technology

[0002] Generally, pistons for automobile brakes are formed by die casting.

[0003] As an example of prior art, Publication No. 10-2006-0041533 describes a core for casting a caliper housing of an automobile brake, which is inserted into a molding space formed between an upper mold and a lower mold of a caliper housing casting die, and wherein the caliper housing is cast by molten metal injected into the caliper housing shaped portion of the molding space.

[0004] A core for casting a caliper housing for an automobile brake is disclosed, characterized by having a left-right symmetrical structure along the inner shape of two caliper housings so that the caliper housings are cast as a pair in a single casting space. Additionally, Publication No. 10-2021-0085555 discloses a method for casting an ultra-lightweight aluminum alloy brake caliper for an electric vehicle. However, in the above prior art, in the movable insert die structure for automobile brake piston die casting, the molten metal flow distance during filling is 560 mm, and solidified molten metal is trapped in the final filling area. Since the defect occurs in the central part of the product thickness, it is difficult to approach for defect resolution. Furthermore, the sleeve filling rate (Long Sleeve = 23.8%) results in solidified molten metal remaining at the ingate entrance of the sleeve (Shot Sleeve = 30.4%). Additionally, there were uneconomical problems caused by degraded quality due to bubbles, erosion, and defects, and high production costs. The problem to be solved

[0005] Therefore, the present invention was devised to solve the above-mentioned problems, and aims to provide an economical automotive brake piston die-casting movable insert mold structure by optimizing the gas exhaust hole and vacuum design in the die-casting process using an automotive brake piston movable insert mold to reduce bubbles, erosion, and defects, thereby improving quality and lowering production costs. means of solving the problem

[0006] The present invention relates to a die-casting movable insert mold structure for an automobile brake piston, comprising a fixed core (10);

[0007] A movable core (20) located at the rear of the fixed core (10);

[0008] It is composed of a movable insert core (30), which is an inner core inserted and coupled into the central hole of the above-mentioned movable core (20); when the movable core (20) with the movable insert core (30) coupled to the rear of the fixed core (10) at the start of die casting, molten metal is injected, and after the die casting is finished, the movable core with the movable insert core coupled to it retracts, and the product piston is removed from the mold.

[0009] Forming three insert overflows (31, 32, 33) for gas discharge in the shape of the above-mentioned movable insert core (30) is for gas discharge, and

[0010] The three insert overflow areas (31, 32, 33) are areas where gas is prone to becoming isolated during the final stage of filling, so they are formed adjacently, but are configured to be separated so that gas can escape from each one.

[0011] From the movable insert core in-gate (21) into the product space, the first insert overflow 1 (31) in the molten metal flow direction is filled with 7 to 15% of the molten metal injection weight, the central insert overflow 2 (32) is filled with 4 to 6%, and the last insert overflow section 3 (33) is filled with 3 to 5%, and an overflow pipe (23) is formed outside the product space.

[0012] Offflow 1 is a concave groove with a fan-shaped cross section, and Offflow 2 is a concave groove with a rectangular cross section; Offflow is formed to be longer in the radial direction than Offflow 1 and 2, and has a cross-sectional shape in which the width decreases due to a step formed in the middle, and the front end has a beveled surface on one side and a straight line on the opposite side, while the rear end has a shape in which both sides are straight lines.

[0013] The molten metal is configured to fill the end portion (1) formed in the runner before flowing into the product space, and if the solidified end portion (1) after casting is not completely filled, it is treated as a defect due to insufficient molten metal, and the end portion (1) is curled.

[0014] The molten metal ratio is such that molten metal is injected in an amount of 380 to 381 parts by weight for the runner and 139 to 140 parts by weight for the overflow, relative to 529 to 530 parts by weight for the piston, which is the product.

[0015] The cooling pipes are arranged to allow for a bidirectional cooling flow. On one side of the mold, the piping is installed so that a horizontal pipe bends at a right angle to be drawn in, then returns to a vertical pipe and becomes a horizontal pipe for drainage. On the other side, cooling water pipes are installed in a concentric, small ring shape to match the circular shape of the piston. These pipes are connected horizontally to both sides of the circular cooling water pipes, allowing the cooling water to be drawn in, circulate through the ring shape, and then discharged, thereby uniformly cooling the molten metal inside the mold.

[0016] Alternatively, instead of a ring-shaped cooling water pipe, a C-type open shape is formed, with an inlet pipe and an outlet pipe connected to each open part, and five spot cooling sections (43) are installed on the opposite side of the open part, so that the part with the slowest solidification is uniformly cooled by the spot cooling section (43) and the open ring section (44) with other parts. Effects of the invention

[0017] Therefore, the present invention optimizes the gas exhaust hole and vacuum design in the die-casting process using an automobile brake piston movable insert mold, thereby reducing bubbles, erosion, and defects, improving quality, and lowering production costs, resulting in significant economic effects. Brief explanation of the drawing

[0018] FIG. 1 is a photograph of the automobile brake piston of the present invention. FIG. 2 is a photograph of the automobile brake piston of the present invention from a different angle. FIG. 3 is an internal photograph of the automobile brake piston of the present invention. FIG. 4a is a front view of the mold of the automobile brake piston of the present invention. FIG. 4b is a side view of the mold of the automobile brake piston of the present invention. FIG. 4c is a rear view of the mold of the automobile brake piston of the present invention. FIG. 5 is an explanatory diagram of the key parts of the automobile brake piston of the present invention. FIG. 6 is a cooling layout diagram of the automobile brake piston of the present invention. FIG. 7 is a diagram showing the additional installation of 5 spot cooling points in the automobile brake piston of the present invention. FIG. 8 is a diagram of the movable insert core of the automobile brake piston of the present invention. FIG. 9 is a perspective view of the fixed core of the automobile brake piston. FIG. 10 is a perspective view of the movable core of the automobile brake piston. FIG. 11 is a vacuum block diagram of the automobile brake piston of the present invention. FIG. 12~14 are performance reports based on the automobile brake piston of the present invention. Specific details for implementing the invention

[0019] The present invention relates to a die-casting movable insert mold structure for an automobile brake piston, comprising a fixed core (10);

[0020] A movable core (20) located at the rear of the fixed core (10);

[0021] It is composed of a movable insert core (30), which is an inner core inserted and coupled into the central hole of the above-mentioned movable core (20); when the movable core (20) with the movable insert core (30) coupled to the rear of the fixed core (10) at the start of die casting, molten metal is injected, and after the die casting is finished, the movable core with the movable insert core coupled to it retracts, and the product piston is removed from the mold.

[0022] Forming three insert overflows (31, 32, 33) for gas discharge in the shape of the above-mentioned movable insert core (30) is for gas discharge, and

[0023] The three insert overflow areas (31, 32, 33) are areas where gas is prone to becoming isolated during the final stage of filling, so they are formed adjacently, but are configured to be separated so that gas can escape from each one.

[0024] From the movable insert core in-gate (21) into the product space, the first insert overflow 1 (31) in the molten metal flow direction is filled with 7 to 15% of the molten metal injection weight, the central insert overflow 2 (32) is filled with 4 to 6%, and the last insert overflow section 3 (33) is filled with 3 to 5%, and an overflow pipe (23) is formed outside the product space.

[0025] Offflow 1 is a concave groove with a fan-shaped cross section, and Offflow 2 is a concave groove with a rectangular cross section; Offflow is formed to be longer in the radial direction than Offflow 1 and 2, and has a cross-sectional shape in which the width decreases due to a step formed in the middle, and the front end has a beveled surface on one side and a straight line on the opposite side, while the rear end has a shape in which both sides are straight lines.

[0026] The molten metal is configured to fill the end portion (1) formed in the runner before flowing into the product space, and if the solidified end portion (1) after casting is not completely filled, it is treated as a defect due to insufficient molten metal, and the end portion (1) is curled.

[0027] The molten metal ratio is such that molten metal is injected in an amount of 380 to 381 parts by weight for the runner and 139 to 140 parts by weight for the overflow, relative to 529 to 530 parts by weight for the piston, which is the product.

[0028] The cooling pipes are arranged to allow for a bidirectional cooling flow. On one side of the mold, the piping is installed so that a horizontal pipe bends at a right angle to be drawn in, then returns to a vertical pipe and becomes a horizontal pipe for drainage. On the other side, cooling water pipes are installed in a concentric, small ring shape to match the circular shape of the piston. These pipes are connected horizontally to both sides of the circular cooling water pipes, allowing the cooling water to be drawn in, circulate through the ring shape, and then discharged, thereby uniformly cooling the molten metal inside the mold.

[0029] Alternatively, instead of a ring-shaped cooling water pipe, a C-type open shape is formed, with an inlet pipe and an outlet pipe connected to each open part, and five spot cooling sections (43) are installed on the opposite side of the open part, so that the part with the slowest solidification is uniformly cooled by the spot cooling section (43) and the open ring section (44) with other parts.

[0030] In addition, the in-gate is characterized by having a vacuum block and an exhaust block for discharging gas formed therein.

[0031] In addition, the piston is characterized by having a plurality of spaced-apart ring grooves formed on the upper part of the cylindrical outer side and a plurality of circular holes formed therein. The o / v gate is a circular or V-shaped gate.

[0032] The above piston is characterized by having a flange formed inwardly on the upper end of the cylinder.

[0033] delete

[0034] The present invention will be described in detail with reference to the attached drawings as follows. Fig. 1 is a photograph of the automobile brake piston of the present invention, Fig. 2 is a photograph of the automobile brake piston of the present invention from a different angle, Fig. 3 is an internal photograph of the automobile brake piston of the present invention, Fig. 4a is a front view of the mold of the automobile brake piston of the present invention, Fig. 4b is a side view of the mold of the automobile brake piston of the present invention, Fig. 4c is a rear view of the mold of the automobile brake piston of the present invention, Fig. 5 is an explanatory diagram of the main parts of the mold of the automobile brake piston of the present invention, Fig. 6 is a cooling layout diagram of the mold of the automobile brake piston of the present invention, Fig. 7 is a diagram of the additional installation of five spot cooling points in the mold of the automobile brake piston of the present invention, Fig. 8 is a diagram of the movable insert core of the automobile brake piston of the present invention, Fig. 9 is a perspective view of the fixed core of the automobile brake piston, and Fig. 10 is a perspective view of the movable core of the automobile brake piston.

[0035] delete

[0036] The present invention relates to a method for manufacturing a piston by die casting, wherein a movable insert is used in the mold. FIG. 1 is a photograph of the automobile brake piston of the present invention, FIG. 2 is a photograph of the automobile brake piston of the present invention from a different angle, and FIG. 3 is an internal photograph of the automobile brake piston of the present invention.

[0037] The reason for using movable inserts is that they protect the mold's gate area from melting, and they allow for replacement and easy modification.

[0038] Furthermore, it facilitates dimensional management of the finished product. To be more specific, regarding the structure and purpose of the movable insert, the reason for using movable inserts (removable insert blocks) in piston molds is that erosion, wear, and defects frequently occur near the gate. By separating this area with an insert, it becomes easy to replace or modify only the part when it wears out or develops a problem, thereby ensuring uniform dimensional and quality control.

[0039] It is characterized by a design that differs in concept from a general core or slide mold, and optimizes and inserts only specific narrow spaces and vulnerable parts. FIG. 4a is a front view of the automobile brake piston mold of the present invention, FIG. 4b is a side view of the automobile brake piston mold of the present invention, FIG. 4c is a rear view of the automobile brake piston mold of the present invention, and FIG. 5 is an explanatory diagram of the key parts of the automobile brake piston mold of the present invention.

[0040] The mold of the present invention is composed of a fixed core (10), a movable core (20), and a movable insert core (30) which is an inner core. The movable core (20) is positioned behind the fixed core (10), and the movable insert core (30) is coupled to the movable core (20) so that they move together. Specifically, when die casting begins, the movable core (20) coupled with the movable insert core (30) is coupled behind the fixed core (10), and molten metal is injected. After die casting is finished, the movable core (20) coupled with the movable insert core (30) retracts, and the product is removed from the mold.

[0041] To explain the shape of the movable insert core (30) and the three overflow holes for gas discharge, three overflow exhaust holes are formed in the movable insert core (30) for gas discharge.

[0042] Since this area is prone to gas isolation during the final stage of charging, three are formed adjacently.

[0043] If the gas is diverted through only a single integrated passage, the escaped gas may flow back in.

[0044] So, it is configured to be separated into three holes so that the gas escapes from each.

[0045] If more gas remains, it is also possible to expand by increasing the hole diameter and exhaust volume.

[0046] Three overflows formed in the die casting are filled last. In the present invention, o / v and o / f are terms mainly used as overflows and are used with the same meaning.

[0047] You can see the shape of the bubbles escaping from the drawing.

[0048] delete

[0049] When explaining the gate, flow, and bubble defect locations, the location of the in-gate (21) and how the molten metal flow proceeds are explained.

[0050] As the molten metal flows in a rotating motion, a vortex (splashed metal) forms at a specific point, and the most bubble defects occur at that point.

[0051] Therefore, by adding vacuum blocks, exhaust blocks, etc., in that vicinity, you can forcibly suck out the bubbles.

[0052] Inside the in-gate (21), the first position overflow section is filled with 7 to 15% of the molten metal injection weight, the central overflow section with 4 to 6%, and the last overflow section with 3 to 5%. The o / v gate (20) has an overflow tube (25) formed on the outside. The overflow tube (25) starts from the opposite side of the central insert overflow and forms an arc outward toward the product space. Before flowing into the product space, the cochlear section (1), which is the end portion formed in the runner (22), is filled. If the cochlear section (1) solidified after casting is not completely filled, it is treated as a defect due to insufficient molten metal. The cochlear section (1) is coiled like the cochlea in the ear.

[0053] Unlike general centrifugal casting, the present invention requires such detailed exhaust, gate, and insert designs because it is a 150kg class high-pressure die casting.

[0054] The gate width is approximately in the range of 0.3 to 0.6T. In sections where the flow rate is too fast and may affect quality, a structure (rib / jaw) is added to slow down the flow rate. A concave portion is formed in the fixed core (10) as shown in FIG. 9 so that when the movable core (20) is joined together, it becomes a set of molds.

[0055] The melting point of aluminum is 660 degrees.

[0056] The present invention minimizes the retention of solidified molten metal by adjusting the position and increasing the size of the OF gate at the defect location to allow the solidified molten metal at the defect location to flow overflow.

[0057] delete

[0058] To describe the mold of the present invention in detail, as shown in FIGS. 8, 9, and 10, the mold is composed of a fixed core (10) and a movable core (20) having a hole formed in the center to allow a movable insert core (30) to be inserted therein. FIG. 8 is a movable insert core of an automobile brake piston according to the present invention, FIG. 9 is a perspective view of a fixed core of an automobile brake piston, and FIG. 10 is a perspective view of a movable core of an automobile brake piston. The movable insert core (30) is composed of a rectangular flange at the bottom and a cylindrical insert part at the top, and three overflows of the insert part are formed in the circumferential direction, each having a different size and shape, and are designed to accommodate the solidification of the molten metal. The overflow 1 (31) is a concave groove with a fan-shaped cross section, and the overflow 2 (32) is a concave groove with a rectangular cross section. The overflow (33) is formed to be longer in the radial direction than the overflow 1 and 2 (31, 32), and has a cross-sectional shape in which the width decreases as a step is formed in the middle. Specifically, the front end has a slanted surface on one side and a straight line on the opposite side, while the rear end has straight lines on both sides. The rear surface of the movable insert core (30) has a space formed in the insertion part to reduce weight. Additionally, coupling holes are formed, and the entire structure is treated with a heat-resistant coating. The casting method described above is formed on the outer circumference of the central hole of the movable core (20). Specifically, on the opposite side of the runner (22) with the snail-shaped part (1) formed at the front end, an overflow pipe (25) through which gas and excess molten metal flow outward is formed in an almost concentric shape around the hole.

[0059] delete

[0060] As illustrated in the cooling arrangement diagram of the automobile brake piston mold of the present invention in FIG. 6, the cooling pipes are arranged to allow for a bidirectional cooling flow. Specifically, on one side of the mold, a horizontal pipe is bent at a right angle to be drawn in, then returns to a vertical pipe, and then becomes a horizontal pipe to be discharged. On the other side, cooling water pipes are installed to form small ring shapes in a concentric pattern to match the circular shape of the piston, and are connected horizontally to both sides of the ring-shaped cooling water pipes so that cooling water is drawn in, circulates through the ring shape, and then discharged. Therefore, the molten metal inside the mold is cooled uniformly.

[0061] Alternatively, instead of a ring-shaped cooling water pipe, a C-type open shape is formed, with an inlet pipe and an outlet pipe connected to each open part. In this case, as shown in the additional installation of five spot cooling points in the automobile brake piston mold of the present invention in FIG. 7, five spot cooling sections (43) are installed on the opposite side of the open part. Therefore, the part that solidifies the slowest is cooled uniformly with other parts by the spot cooling section (43) and the open ring part.

[0062] The present invention minimizes the retention of solidified molten metal by adjusting the position and increasing the size of the OF gate at the defect location, thereby causing the solidified molten metal at the defect location to flow overflow.

[0063] The optimal values ​​are that the product unit weight is 529.5 (g), the runner weight is 379.3 (g), the o / f weight is 139.5 (g), and the total weight is 1048.3 (g).

[0064]

[0065] FIG. 11 is a vacuum block diagram of the automobile brake piston mold of the present invention, and FIG. 12 to 14 are test results of the automobile brake piston mold of the present invention.

[0066] delete

[0067] Therefore, the present invention optimizes the movable insert, gas exhaust hole, and vacuum design that occur in the die-casting process using an automobile piston mold, thereby reducing bubbles, erosion, and defects, which improves quality and lowers production costs, resulting in significant economic effects.

[0068] delete Explanation of the symbols

[0069] 10 : Fixed core 20 : Operating core 30 : Movable insert core 31, 32, 33 : Insert Overflow(o / v,o / f) 1, 2, 3 21 : In-gate 22 : Runner 23 : Injection port 25 : Overflow pipe (o / v, o / f) 24 : Parting line 41: Left cooling section 42: Right cooling section 43: Spot cooling section 44: C-type cooling section 1 : Cochlea section (molten metal filling monitoring section)

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