KR102169706B1 - Die casting system with jet cooler applied - Google Patents

Abstract

The present invention relates to a die casting system to which a jet cooler is applied, and consists of a fixed mold 200, a movable mold 300, a core and a jet cooler, and is bonded to one surface of the fixed mold 200 in the movable mold 300. A portion of the shape of the rack housing is engraved on the joint surface, and the one surface and the joint surface are joined, so that the shape of the rack housing and the runner, which is a passage for supplying molten metal to the rack housing, and a gas discharge channel for discharging gas to the upper part of the rack housing are connected. A power pack assembly hole 131 into which a power pack can be inserted is formed in the power pack assembly unit 130 formed to form a space of the shape and formed at the other end of the rack housing shape, and has a circular passage shape forming the power pack assembly hole 131. The runner connected to the front is the main runner, and only one of the main runners is connected, so that when the molten metal is supplied to the circular passage at a constant pressure, the flow of molten metal injected from different directions collides with each other to prevent air bubbles from being generated. As a result, it is intended to provide a die casting system with a jet cooler that circulates the circular passage and suppresses the occurrence of air bubbles inside the circular passage.

Description

Die casting system with jet cooler applied}

The present invention relates to a die casting system for producing automobile parts.

The steering device is a device necessary to arbitrarily change the driving direction of the vehicle, and it is largely divided into a mechanical steering device and a power steering device.

Among power steering devices, the power steering system is a boosting device that uses the hydraulic pressure of a hydraulic pump driven by an engine as a power source so that a car can be turned with light steering force. In recent power steering systems, rack and pinion methods are mainly introduced, and the housing in which the rack gear is built is the rack housing. For reference, the rack gear herein may be a conventional rack gear, or may be a base gear for moving the ball screw, or the outer surface of the ball screw itself may be formed as a rack gear. In addition, the specific shape of the rack housing is manufactured differently depending on the type of vehicle.

More specifically, the configuration of the power steering system is configured as shown in FIG. 1.

On the other hand, the rack housing is made of a light metal material to reduce the weight of the vehicle, and therefore, in terms of productivity of the lightweight metal, it is manufactured in a die casting method to improve productivity.

In general, die casting is also referred to as die casting, and precision to obtain the same casting as the mold by injecting molten metal into a steel mold die precisely machined to match the required casting shape. As a casting method, a product produced by the casting method is called a die-cast casting.

Since the rack housing is also manufactured by die casting, it is important to minimize defects caused by air bubbles or internal shrinkage voids, which are the main defects. Therefore, it is necessary to minimize the occurrence of local defects due to uniform cooling over the entire area.

Since the rack housing is a component of a vehicle, weight reduction is important, but durability and mechanical soundness for stability are also important. The shape characteristics of the rack housing itself are important to achieve both the demands of weight reduction and mechanical integrity, which are difficult to harmonize with each other, but the casting process is also important for mechanical integrity.

However, in the case of the casting manufacturing process, if the shape of the finished product, the rack housing itself, is the same without any change, the casting manufacturing process also has little room for improvement, so there are many difficulties in manufacturing a rack housing having better mechanical soundness.

Registered Patent Publication No. 10-1836650 (announcement date: 2018. 03. 09)

Accordingly, an object of the present invention is to provide a die casting system that can guarantee maximum mechanical integrity so that a lightweight rack housing can have excellent characteristics in terms of mechanical rigidity.

In the die casting system according to the present invention for achieving this purpose, a part of the shape of the rack housing is engraved on one side and a fixed mold 200 having a fixed position, and a fixed mold 200 that is bonded to or separated from one surface of the fixed mold 200. As a mold, a part of the shape of the rack housing is engraved on the bonding surface that is bonded to one surface of the fixed mold 200, and the one surface and the bonding surface are bonded to each other, thereby providing the shape of the rack housing and runners and racks that are passages for supplying molten metal to the rack housing. It is installed between the movable mold 300 and the fixed mold 200 and the movable mold 300, which is manufactured to form a space in which a gas discharge channel for discharging gas is connected to the upper part of the housing. A core (not shown) that forms a hollow shape in a rack housing-shaped casting by being inserted in a sliding manner, and a conventional jet cooler (not shown) for casting that is inserted between the fixed mold and the movable mold to control the cooling rate of the casting. Is composed.

Here, the rack housing shape is a rack shaft 120 formed in a long horizontal direction in the center, a yoke hole portion 110 formed at one end of the rack shaft 120, and a power pack formed at the other end of the rack shaft 120 It consists of an assembly unit 130.

The runner consists of a plurality of main runners and branch runners branching from each of the main runners, and a gate formed at the end of each main runner or branch runner is connected to the shape of a rack housing, and the molten metal moves along each main runner or branch runner. It can be injected into the shape of the rack housing.

In addition, a power pack assembly hole 131 into which a power pack can be inserted is formed in the power pack assembly unit 130 formed at the other end of the rack housing shape, and the runner connected to the front of the circular passage forming the power pack assembly hole 131 is the main It is a runner, and only one of the main runners is connected, so when the molten metal is supplied to the circular passage at a constant pressure, the flow of molten metal injected from different directions collides, preventing bubbles from being generated, while circulating the circular passage at a constant pressure. The generation of air bubbles inside the passage is suppressed.

At this time, the outer portion of the rim of the rack housing shape and the runner and the gas discharge channel shape among the areas in which one surface of the fixed mold 200 and the bonding surface of the movable mold 300 contact each other is preferably made of Viton resin. The sealing material is attached to minimize external inflow air.

In addition, in the main runner connected to the circular passage, a portion adjacent to the circular passage is preferably a part of a virtual cylindrical outer circumferential surface passing through the circular passage so as to prevent interference with the core inserted by sliding motion to form a circular passage shape. It is formed as a curved sector 1631 forming the shape of.

In this case, the point at which the gate connected to the circular passage is installed among both ends of the curved sector 1631 is a point coincident with the direction in which the molten metal is rotated along the circular passage. Is determined.

Here, a pocket partition wall 1632 is preferably formed at the gate portion to form a space by branching from the inner surface of the curved sector 1631 and extending toward the circular passage, the space being the curved sector 1631 It is a return pocket 1633 in which air bubbles generated in the process of rotating the circular passage by the molten metal passing through the and gates in turn are collected.

In this case, the pocket partition wall 1632 forming the return pocket 1633 is preferably inclined in a direction in which the molten metal proceeds.

In particular, the end of the pocket partition wall 1632 is preferably bent in a direction opposite to the inclination, so that air bubbles driven by the molten metal flowing along the circular passage are easily collected into the return pocket 1633.

In addition, the gas discharge channel is a gas discharge channel on the side of the yoke hole unit 110 for discharging gas from the yoke hole unit 110 and a gas discharge channel on the side of the power pack assembly unit 130 for discharging gas from the power pack assembly unit 130 However, preferably, a pocket gas discharge channel for directly connecting the return pocket 1633 and the gas discharge channel on the side of the power pack assembly unit 130 is installed in the return pocket 1633.

The die-casting system to which the jet cooler according to the present invention is applied not only minimizes the occurrence of bubbles inside the casting due to the branching shape of the molten metal flow path and the position of the gate, but also forms a space where bubbles generated during the process of the molten metal can be removed. As a result, the mechanical properties of the product are improved, so that even if the product is manufactured to be lighter than before, equivalent mechanical properties are secured, thereby achieving weight reduction.

1 is an exploded perspective view of a vehicle steering system including a rack housing,
2 is a perspective view of the rack housing,
3 is a photograph of a fixed mold 200 in the die casting system according to the present invention,
4 is a photograph of a movable mold 300 in the die casting system according to the present invention,
5 is a front view of a mold shape formed by bonding the fixed mold 200 of FIG. 3 and the movable mold 300 of FIG. 4;
6 is a perspective view of the mold shape of FIG. 5;
7A is a front view showing a core application position and a direction in which the core proceeds,
7B is a plan view showing a parting line;
8 is a perspective view showing an application position and a gas discharge direction of a gas discharge port;
9 is a photograph of a conventional mold shape and a shape solidified into the mold shape of FIG. 5;
10 is an enlarged photograph of each of the power pack assembly units in FIG. 9;
11 is an enlarged perspective view of the power pack assembly in FIG. 6;
12 is a perspective view showing the internal structure of FIG. 11;
13A is a conceptual diagram of FIG. 12;
13B is a perspective view showing the flow of molten metal in FIG. 12;

Specific structural or functional descriptions presented in the embodiments of the present invention are exemplified only for the purpose of describing the embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described in the present specification, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The die casting system according to the present invention includes a fixed mold 200, a movable mold 300, a core (not shown) and a jet cooler (not shown) as shown in FIGS. 3 and 4.

The fixed mold 200 is a mold in which a part of the shape of the rack housing is engraved on one surface and the position is fixed.

The movable mold 300 is a mold that can be moved forward or retracted toward the fixed mold 200 and is bonded to or detached from one surface of the fixed mold 200. A part of the shape of the rack housing is engraved on the bonding surface of the movable mold 300 to be bonded to one surface of the fixed mold 200. At this time, the one surface of the fixed mold 200 and the bonding surface of the movable mold 300 are joined, so that the shape of the rack housing and the gas outlet for discharging gas to the top of the rack housing and the runner, which is a passage for supplying molten metal to the rack housing, are all connected. A space of shape is formed.

The core (not shown) is installed between the fixed mold 200 and the movable mold 300, and is inserted into the rack housing-shaped space in a sliding manner to form a hollow shape in the rack housing-shaped casting.

A jet cooler (not shown) is a jet cooler for local cooling commonly used in metal castings, and is inserted between a fixed mold and a movable mold to control the cooling rate of the casting. At this time

The shape of the rack housing formed when the movable mold 300 and the fixed mold 200 are in contact with each other is a rack shaft 120 formed in a long horizontal direction in the center as shown in FIG. 3, and at one end of the rack shaft 120. It consists of a yoke hole portion 110 that is formed and a power pack assembly portion 130 formed at the other end of the rack shaft 120.

A form in which a runner, which is a passage through which the molten metal is supplied, and a gas outlet, are integrally attached to the shape of a rack housing, is shown in the front view of FIG. 5 and the perspective view of FIG. 6.

For reference, in the drawings shown in FIGS. 5 to 13B, the rack housing and runner-shaped casting and the gas outlet-shaped casting are shown as the present invention, but the present invention is the rack housing mold itself. To FIG. 13B are shown in the form of a cast solidified in the mold for convenience in order to explain the shape of the rack housing mold. Accordingly, the castings of FIGS. 5 to 13B will be regarded as being inscribed in the fixed mold 200 and the movable mold 300 in the following.

In the die-casting system according to the present invention, as shown in FIG. 7A, a total of five hydraulic piston-type slide cores are applied with two mounting parts, two rack holes, and one power pack assembly 130.

Since it is desirable to minimize the sliding distance in the depth direction of the mold in the application direction of these slide cores, the mounting part formed the longest among the remaining core application parts except for the sliding core in the direction of the rack axis 120 that enters in the horizontal direction anyway. Based on (the first sliding core direction 141 in FIG. 7 ), the parting line serving as the shape reference of the movable mold 300 and the fixed mold 200 is the first sliding core direction ( 141) is split in half. Accordingly, when FIG. 7A is a front view of the rack housing, FIG. 7B corresponds to a plan view of the rack housing.

As shown in FIG. 5, the runner is composed of a plurality of main runners 161, 162, 163 and a branch runner branching from each of the plurality of main runners 161, 162, 163, and each main runner 161, 162, 163 or a gate formed at the end of the branch runner is The molten metal which is connected to the shape of the rack housing and moves along the respective main runners 161, 162, 163 or branch runners is injected into the shape of the rack housing.

In addition, as shown in FIG. 6, a power pack assembly hole 131 into which a power pack (not shown) can be inserted is formed in the power pack assembly unit 130 formed at the other end of the rack housing shape.

At this time, the main runner 163 connected to the front of the circular passage forming the power pack assembly hole 131 is one of the plurality of main runners 161, 162, and 163.

Conventionally, as shown in the left photo of FIG. 9 and the left photo of FIG. 10, two branch runners are connected to the power pack assembly unit 130 so that the molten metal enters the shape of the power pack assembly unit 130 at the same time in the two branch runners. In this case, referring to the left photo of FIG. 10, a red arrow indicates a direction in which the two branch runners respectively supply molten metal to the power pack assembly unit 130. For reference, the point marked by the red arrow corresponds to the gate.

The molten metal supplied from the two branch runners finally exits in the direction of the blue arrow.Before that, the molten metal supplied from the two branch runners meets at the square indicated by the blue dotted line, and the air bubbles driven by the molten metal also meet each other to isolate the flow. As the air bubbles become stagnant. Therefore, in the related art, there is a high possibility that a bubble defect occurs in a rectangular area indicated by a blue dotted line, resulting in a result that the stability of the power pack assembly unit 130 is lowered.

Therefore, in the present invention, first, one third main runner 163 rather than one branch runner is connected to the power pack assembly unit 130 as shown in the right drawing of FIG. 10. In this case, the reason that the runner connected in the right drawing of FIG. 9 is the main runner is that the injection pressure of the molten metal is maintained equal to that of the two runners while the injection pressure of the molten metal is maintained equal to that of the two runners, unlike the conventional two, and the power pack assembly unit 130 It is to be evenly distributed within the shape.

Therefore, when the third main runner 163 is connected to the power pack assembly unit 130 as shown in the right picture of FIG. 10, the flow of the supplied molten metal meets and exits through the point where the power pack assembly unit 130 is connected to other parts. The occurrence of isolation of air bubbles driven by the molten metal is suppressed.

Although not shown for reference, the outer portion of the rim of the rack housing shape and the runner and gas outlet shape among the areas where one surface of the fixed mold 200 and the bonding surface of the movable mold 300 contact each other is made of Viton resin. The sealing material is attached to minimize external inflow air.

Meanwhile, a portion adjacent to the circular passage in the third main runner 163 connected to a circular passage shape (hereinafter referred to as a “circular passage”), which is a shape forming the power pack assembly unit 130, is on the right side of FIG. As shown in the photo and Fig. 11, to form a circular passage shape, it is formed as a curved sector 1631 forming a part of the outer peripheral surface of a virtual cylindrical shape passing through the circular passage so as to prevent interference with the core inserted by sliding motion. do.

In order to form the circular passage shape, a cylindrical core is inserted from the outside. At this time, there is a risk of interference between the core and the main runner. Therefore, in the present invention, the shape of the main runner is manufactured to be curved to form a part of the cylindrical wall surface so that interference with the core can be prevented. In this way, the curved portion of the main runner is referred to as a'curved sector 1631'. In addition, the gate refers to a point at which the molten metal flowing through the curved sector 1631 begins to enter the circular passage, although a separate reference numeral is not given.

Since the section between the curved sector 1631 and the gate is formed in a direction perpendicular to the circular passage as shown in the photo on the right of FIG. 10 and in FIG. 11, in principle, the molten metal enters the circular passage in both directions with the gate as the center. It goes on. Therefore, each flow of molten metal proceeds in a semicircle, then merges from the other side and enters the other part.

However, if the direction of the curved part is used, the flow of molten metal can make the circular passage flow in one direction. In this case, when the molten metal flows through the circular passage in one direction, the flow of the molten metal is also one, so that the two flows collide as in the prior art, thereby preventing the bubbles from stagnating.

However, in this case, there is a problem in the treatment of bubbles driven by the molten metal returning one round through the circular passage. If the bubbles driven by the molten metal cannot escape, there is a fear that the bubbles will stagnate at the point where the molten metal returns by turning one round in the circular passage.

Therefore, as a modified embodiment, as shown in FIG. 12, the return pocket 1633 is formed by the installation of the pocket partition wall 1632, and the air bubbles that cannot be accommodated in the return pocket 1633 are separately provided. Through the power pack assembly unit 130 side may be configured to exit through the gas discharge channel.

In this case, since the flow of the molten metal is formed to mainly flow in one direction inside the circular passage, in this case, the directionality of the curved sector 1631 described above may be helpful.

That is, the molten metal passing through the curved sector 1631 flows in an arc due to the shape of the curved sector 1631 as shown in FIG. 11. At this time, the point at which the gate connected to the circular passage is installed among both ends of the curved sector 1631 may be determined as a point in which the molten metal flowing inside the curved sector 1631 coincides with the direction in which the molten metal is rotated along the circular passage.

That is, the flow rate of the molten metal flowing along the circular passage can be determined according to which side of the gate, which is the point at which the molten metal enters the circular passage through the curved sector 1631, among both ends of the curved sector 1631 is turned.

In this case, as illustrated in FIG. 12, a pocket partition wall 1632 may be formed at the gate portion to form a space by branching from the inner surface of the curved sector 1631 and extending in a shape to open toward the circular passage.

The space formed by the pocket bulkhead 1632 is a space in which bubbles generated in the process of rotating the circular passage by the molten metal that in turn passes through the curved sector 1631 and the gate are collected, so hereinafter'return pocket 1633' It will be called as.

The pocket partition wall 1632 forming the return pocket 1633 may be inclined in a direction in which the molten metal proceeds, thereby determining a moving direction of the molten metal. In particular, since the flow of the molten metal is in a clockwise direction as seen in Fig. 12 due to the pocket partition wall 1632, the pocket partition wall 1632 has a slope as shown in Fig. 12 so that the flow of the molten metal is formed in a clockwise direction even within the circular passage.

Since the rotational flow formed by the curved sectors 1631 is maintained even in the circular passage due to the inclination of the pocket partition wall 1632, the molten metal can rotate the circular passage with a predetermined pressure or more.

In addition, the end of the pocket partition wall 1632 is rather bent in a direction opposite to the overall inclination of the pocket partition wall 1632, as shown in FIG. 13, so that bubbles flowing along the circular passage are driven into the return pocket 1633. It can be easily collected.

That is, the end of the pocket partition wall 1632 is inclined in a direction opposite to the overall slope of the pocket partition wall 1632, so that the molten metal returned by turning the circular passage is not mixed with the molten metal newly entering the circular passage. Bubbles driven by the molten metal being driven may also be collected into the return pocket 1633 without being mixed with the newly entered molten metal.

For reference, the entire gas outlet is a gas outlet on the side of the yoke hole unit 110 for discharging gas from the yoke hole unit 110 and a side of the power pack assembly unit for discharging gas from the power pack assembly unit 130 as shown in FIG. It consists of a gas outlet 152. As shown in FIG. 8, when the connection direction between the gas outlet and the shape of the rack housing is based on a portion protruding outward from the overall shape of the rack housing, air bubbles can be effectively discharged with only the minimum gas outlet. The injection pressure can also be lowered further.

However, due to the large amount of air bubbles collected in the return pocket 1633, there may be a case that not all of the air bubbles are accommodated in the return pocket 1633. In preparation for such a case, in the present invention, as shown in FIG. 11, a pocket gas discharge channel 1521 for directly connecting the return pocket 1633 and the gas discharge port 152 on the side of the power pack assembly may be installed.

Gases generated from the air bubbles inside the return pocket 1633 through the pocket gas discharge channel are continuously discharged through the gas outlet 152 on the side of the power pack assembly, thereby conventionally occurring in the power pack assembly 130 of the rack housing. The resulting bubble defect is minimized, so that the mechanical integrity of the rack housing can be improved, and thus, the design range of the more lightweight rack housing can be expanded.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes are possible within the scope of the technical spirit of the present invention. It will be obvious to those who have the knowledge of.

P: Parting line
1: pinion 2: rack bar
3: rack tire connection assembly 4: rack housing
5: support yoke assey 6: yoke spring
7: yoke plug 8: bearing
9: pinion plug 10: dust cap
11: dust packing 20: rack bush Asei
21: rack bush 22: damper O-ring
110: yoke hole 120: rack shaft
130: power pack assembly 131: power pack assembly hole
141: first core sliding direction 142: second core sliding direction
143: third core sliding direction 144: fourth core sliding direction
145: 5th core sliding direction 151: yoke hole side gas outlet
152: power pack assembly side gas outlet 160: inlet
161: first main runner 162: second main runner
163: 3rd main runner 200: fixed mold
300: movable mold 400: core
1521: pocket gas discharge channel 1631: curved sector
1632: pocket bulkhead 1633: return pocket

Claims (8)

A fixed mold 200 in which a part of the shape of the rack housing is engraved on one side and the position is fixed;
As a mold that can be bonded to or separated from one surface of the fixed mold 200, a part of the shape of the rack housing is engraved on the bonding surface that is bonded to one surface of the fixed mold 200, and the one surface and the bonding surface are joined. , A movable mold 300 manufactured to form a space having a shape in which a rack housing shape and a gas discharge channel for discharging gas to the upper portion of the rack housing and a runner, which is a passage for supplying molten metal to the rack housing, are connected;
A core installed between the fixed mold 200 and the movable mold 300 and inserted in a sliding manner into the rack housing-shaped space to form a hollow shape in the rack housing-shaped casting; And,
It consists of a jet cooler that is inserted between the fixed mold and the movable mold to control the cooling rate of the casting,
The rack housing shape is a rack shaft 120 formed in a long horizontal direction in the center, a yoke hole portion 110 formed at one end of the rack shaft 120, and a power pack formed at the other end of the rack shaft 120 Consisting of part 130,
The runner consists of a plurality of main runners and branch runners branching from each of the main runners, and a gate formed at the end of each main runner or branch runner is connected to the shape of a rack housing, and the molten metal moves along each main runner or branch runner. Can be injected into this rack housing shape,
A power pack assembly hole 131 into which a power pack can be inserted is formed in the power pack assembly unit 130 formed at the other end of the rack housing shape, and the runner connected to the front of the circular passage forming the power pack assembly hole 131 is the main It is a runner, and only one of the main runners is connected, so when the molten metal is supplied to the circular passage at a constant pressure, the flow of molten metal injected from different directions collides, preventing bubbles from being generated, while circulating the circular passage at a constant pressure The generation of air bubbles inside the passage is suppressed,
Among the areas where one surface of the fixed mold 200 and the bonding surface of the movable mold 300 contact each other, a sealing material made of Viton resin is attached to the outer portion of the rim of the rack housing shape and the runner and gas discharge channel shape. To minimize external inflow air,
In the main runner connected to the circular passage, the portion adjacent to the circular passage forms a part of a virtual cylindrical outer circumferential surface passing through the circular passage so as to prevent interference with the core inserted by sliding motion to form a circular passage shape. Formed of curved sectors 1631,
The point at which the gate connected to the circular passage is installed among both ends of the curved sector 1631 is determined as a point in which the molten metal flowing inside the curved sector 1631 matches the direction in which the molten metal is rotated along the circular passage. Die-casting system with jet cooler applied. delete delete delete The method of claim 1,
A pocket partition wall 1632 is formed in the gate portion to form a space by branching from the inner surface of the curved sector 1631 and extending toward the circular passage, and the space sequentially connects the curved sector 1631 and the gate. A die-casting system to which a jet cooler is applied, characterized in that it is a return pocket (1633) in which bubbles generated in the process of rotating the circular passage by the molten metal that has passed through are collected. The method of claim 5,
The die-casting system to which the jet cooler is applied, characterized in that the pocket partition wall (1632) forming the return pocket (1633) has a slope formed in a direction in which the molten metal proceeds. The method of claim 6,
The end of the pocket partition wall 1632 is bent in a direction opposite to the inclination, so that the air bubbles driven by the molten metal flowing along the circular passage are easily collected into the return pocket 1633. system. The method of claim 7,
The gas discharge channel is made of a gas discharge port on the side of the yoke hole unit 110 for discharging gas from the yoke hole unit 110 and a gas discharge port on the side of the power pack assembly unit for discharging gas from the power pack assembly unit,
In the return pocket 1633, a pocket gas exhaust channel 1521 for directly connecting the return pocket 1633 and the gas outlet 152 on the side of the power pack assembly unit is installed.

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