KR20230093814A - Turbine housing mold assembly and an investment casting of the same - Google Patents

Abstract

A mold assembly for precision casting of a turbine housing according to an embodiment of the present invention comprises: a plurality of product forming parts arranged radially; a single injection cup positioned at the radial center of the plurality of product forming parts for injecting molten metal into the plurality of product forming parts; a first runner moving the molten metal injected through the single injection cup vertically downward toward the plurality of product forming parts; a second runner radially branching to move the molten metal from the first runner to the plurality of product forming parts where the turbine housing is formed; independent pressure parts installed parallel and vertically upward relative to each of the plurality of product forming parts and installed lower than the height of the first runner to provide independent pressures so that the molten metal of a constant pressure is injected into the plurality of product forming parts through the second runner between the first runner and the plurality of product forming parts; and a plurality of gates radially and sequentially positioned at different heights relative to the second runner. Therefore, the mold assembly for precision casting can remove slag or impurities from the molten metal and minimize the generation of turbulence in the molten metal.

Description

Turbine housing mold assembly and mass production precision casting method using the same {TURBINE HOUSING MOLD ASSEMBLY AND AN INVESTMENT CASTING OF THE SAME}

The present invention relates to a turbine housing mold assembly and a turbine housing mass production precision casting method using the same, and more particularly, to a turbine housing mold assembly capable of precisely casting at least two or more turbine housings at once and a turbine housing mass production precision casting method using the same. It is about.

Casting makes a product by pouring molten metal into the mold and solidifying it after making a mold, so it is easy to make a product with a complex shape and has the advantage of being able to mass-produce.

As the conventional technology for casting a turbine housing according to the expanded application of gasoline turbochargers, in Patent Registration No. 1145629 and Patent Publication No. 2012-0064452, twin-scroll turbine housings for turbochargers formed integrally with the exhaust manifold are has been initiated.

These conventional techniques are intended to solve the problem of tissue imbalance due to cooling that frequently occurs in the relatively thin port or confluence of the turbine housing in which the scroll is formed, and has a structure in which only a single casting can be cast in one mold. There is a problem in that casting productivity and recovery rate decrease because it is limited to.

In this situation, the need for mass production of turbine housings emerges according to the recent trend of vehicle diversification, weight reduction, and manufacturing cost reduction, and casting productivity is improved by improving the conventional mold, which was limited to a structure that can only cast a single casting in a mold. And the development of a mold capable of improving the recovery rate and the development of a casting method using the mold are urgently needed.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to remove slag or impurities from molten metal, minimize the occurrence of turbulence in molten metal, achieve sufficient static pressure in a plurality of product forming parts, and generate directional solidification. It is to provide a turbine housing mold assembly capable of precision casting four or more turbine housings at once and a turbine housing mass production precision casting method using the same.

A mold assembly for precision casting of a turbine housing according to an embodiment of the present invention includes a plurality of radially arranged product molding parts, and a radial center of the plurality of product molding parts to inject molten metal into the plurality of product molding parts. A single injection cup disposed thereon, a first runner that moves the molten metal injected through the single injection cup vertically downward toward the plurality of product forming parts, and a space in which a turbine housing is formed from the first runner, wherein the plurality of products A radially branched second runner to move molten metal to the forming unit, and molten metal at a constant pressure to be injected into the inside of the plurality of product forming units through the second runner between the first runner and the plurality of product forming units An independent pusher installed side by side vertically upward for each of the plurality of product forming parts to provide pressure independent of each other, but installed lower than the height of the first runner, and a radially sequential height difference with respect to the second runner It is characterized in that it includes a plurality of gates disposed.

A turbine housing precision casting method using a mold assembly for precision casting of a turbine housing according to another aspect of the present invention includes an injection cup into which heat-resistant molten metal is injected, a first runner connected to the injection cup, and branching in four directions The second runner, the first to fourth gates communicating with the corners of the second runner, and a plurality of turbine housing product shape parts corresponding to the turbine housing shape composed of a dissipation model, and the number of the turbine housing product shape parts preparing independent presses as much as possible, installing a strainer inside the injection cup, connecting it to the large diameter part of the first runner, and standing the first runner upright in the direction of gravity; arranging the small-diameter portion of the runner to communicate with the central communication portion of the second runner, and communicating and coupling the first to fourth gates in the order of height in a clockwise direction with respect to four corners of the second runner; Installing a plurality of the turbine housing product shape parts sequentially so that the thin plate sheet parts of the turbine housing product shape face each other with respect to the first to fourth gates so as not to interfere in the height direction, and the thin plate sheet in the turbine housing product shape part and arranging independent pushers parallel to the first runner at a position farthest from the first runner so that a positive pressure is formed against the turbine housing product shape.

A mold assembly for precision casting of a turbine housing and a turbine housing precision casting method using the same according to an embodiment of the present invention remove slag or impurities from molten metal, minimize turbulence in molten metal, and provide sufficient static pressure to a plurality of product molding parts. and directional solidification occurs, so that four or more turbine housings can be precision cast at once.

1 is a perspective view of a turbine housing precision casting method for explaining a turbine housing precision casting method according to an embodiment of the present invention.
Figure 2 is an exploded perspective view of Figure 1
Figure 3 is a partially exploded perspective view of Figure 1
4 is a flow chart illustrating a precision casting method of a turbine housing according to a modified embodiment of the present invention;
Figure 5 is an exploded perspective view of a turbine housing precision casting method for explaining the precision casting method of the turbine housing according to a modified embodiment of the present invention.
Figure 6 is a combined perspective view of the turbine housing precision casting method for explaining the precision casting method of the turbine housing according to a modified embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

All technical terms used in the present invention, unless otherwise defined, have the following definitions and correspond to the meanings commonly understood by those of ordinary skill in the art related to the present invention. In addition, although preferred methods or samples are described in this specification, those similar or equivalent thereto are also included in the scope of the present invention.

Throughout this specification, unless the context requires otherwise, the terms "comprise" and "comprising" include a given step or element, or group of steps or elements, but any other step or element, or It is to be understood that steps or groups of components are not excluded.

1 is a perspective view of a turbine housing precision casting method for explaining a turbine housing precision casting method according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 is a partially exploded perspective view of FIG. 1 .

1 to 3, the mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention includes a plurality of product molding parts 110 arranged radially, and the plurality of product molding parts ( 110), an injection cup 120 disposed at the radial center of the plurality of product forming parts 110, and the molten metal injected through the injection cup 120 is injected into the plurality of product forming parts 110. ) and the first runner 130 that moves vertically downward, and the plurality of product forming parts 110, which is a space in which the turbine housing is formed, from the first runner 130. The second branched to move the molten metal It consists of a runner 140, and a certain pressure is applied between the first runner 130 and the plurality of product forming parts 110 to the inside of the plurality of product forming parts 110 through the second runner 140 Independent presses 160 sealed with independent pressure so that the molten metal is injected are installed side by side vertically upward with respect to each of the plurality of product forming parts 110.

In the mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention, a funnel-type strainer 121 in which the hole size of the impurity filtering hole increases toward the center is installed inside the injection cup 120, so that the molten metal is injected into the injection cup 120 is once cooled to remove slag or impurities so that they can move through the first runner 130.

The first runner 130 is a tubular member with a circular cross section, and can minimize turbulence in the molten metal. It is configured to maintain a constant temperature while moving the runner 130.

The lower surface of the first runner 130 is formed to be tapered in the downward direction, and a plurality of second runners 140 are formed in a diagonally intersecting direction at the vertical lower end of the first runner 130. .

The second runner 140 includes a communication portion with the first runner 130 and a branch portion radially branched from the communication portion, preferably in a cross shape, and the branch portion may have the same length. there is.

The second runner 140 is configured to communicate with the vertical lower end of the first runner 130, and uniform molten metal can be supplied from the first runner 130 to the plurality of product forming parts 140 It has a sufficient size so as to be formed, and is characterized in that it is configured to solidify later than the product forming unit 140.

It is possible to provide high pressure by being disposed in the center of the second runners 140 as high as possible so that positive pressure is formed from the first runner 130 to the plurality of product forming parts 140 through the second runner 140. It is configured so that the second runners 140 are formed to face each other, so that directional solidification can occur toward the second runner 140 from the product forming part 140. It is preferable that is distributedly installed with respect to the product forming unit 140.

In this way, by maintaining the molten metal height of the first runner 130 constant higher than the molten metal height of the second runners 140, the thin plate portion 141a of the turbine housing product forming unit 141 to the scroll portion 141c ), it is advantageous for thin casting, and casting defects can be minimized, and casting defects such as not filling the molten metal can be prevented by increasing the fluidity of the molten metal.

The independent presser 160 forms a constant pressure in a direction perpendicular to the product forming unit 140, is installed lower than the height of the first runner 130, and molds the product through the gate 150 The part 140 has a sequential height so that the molten metal can be sequentially filled into the product forming part 140, and the independent pressurizing part 160 forms an independent pressure against the product forming part 140. And, the high pressure is applied toward the independent pusher 160 to collect impurities and remove the independent pusher 160 after completion of casting, thereby preventing impurities from being formed in the product molding unit 140.

In addition, since the independent pusher 160 is disposed within different radii at different heights with respect to the first runner 130, material consumption can be minimized and removal of the independent pusher 160 is easy. .

In general, the product-shaped portion 110 of the turbine housing has a spiral-shaped scroll portion having a predetermined angle with respect to the plate-shaped intake port, and it is important to accurately position the position of the center of the spiral of the scroll portion and the phase of the swirl with respect to the intake port. Since it is very important, it is very difficult to install the product shape portion 110 without interfering with the three-dimensional structure.

In the mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention, the thin plate sheet parts of the scroll part of the product shape part 110 are disposed at different heights with respect to the second runner 140, respectively. A plurality of gates 150 may be formed.

The plurality of gates 150 include a first gate 150a communicating with the first corner of the second runner 140, a second gate 150b communicating with the second corner, and a third communicating with the third corner. It includes a third gate 150c and a fourth gate 150d communicating with a fourth corner, and the first to fourth gates 150a, 150b, 150c, and 150d are scrolls of the turbine anti-aging product shape portion 110. It is configured to have a height difference in one direction so as not to interfere with each other in consideration of the negative phase.

Therefore, the turbine housing product shape parts 110 are spaced at regular intervals in different directions.

As the turbine housing product shape portion 110 is formed with a height difference in this way, molten metal is not simultaneously injected into each of the turbine housing product shape portion 110, but the first to fourth gates 150a, 150b, and 150c , 150d), and the injection is made sequentially, and it can be seen through [Table 1] that the problem of tissue imbalance due to cooling occurs less when the plurality of turbine housing product shape parts 110 are injected sequentially.

[Table 1] shows that when the heights of the first to fourth gates 150a, 150b, 150c, and 150d are the same with respect to the turbine housing product shape portion 110, the first to fourth gates 150a, When the heights of the gates 150b, 150c, and 150d are randomly varied, and when the heights of the first to fourth gates 150a, 150b, 150c, and 150d are constantly increased clockwise or counterclockwise, 10 or more times are performed. It shows the results of casting experiments and inspecting casting defects.

bubble generating area non-charging area cooling imbalance When multiple gates have the same height error error error When multiple gate heights are randomly varied error Good error When the heights of multiple gates are uniformly varied in one direction Good Good Good

At this time, the molten metal used an austenitic heat-resistant cast steel with excellent strength at high temperatures and machinability, and in terms of weight ratio, C: 0.2 to 0.6%, Si: 2% or less, Mn: 2% or less, Ni: 8 ~ 20%, Cr: 15 ~ 30%, Nb: 0.2 ~ 1%, W: 1 ~ 6%, N: 0.01 ~ 0.3%, balance: Fe and unavoidable impurities may be included.

Hereinafter, a turbine housing precision casting method using the mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention will be briefly described with reference to FIG. 4 .

Referring to FIG. 4, the turbine housing precision casting method using the mold assembly 100 for precision casting of the turbine housing according to an embodiment of the present invention includes one injection cup 120 and one first runner 130 And, the second runner 140 branched in four directions, the first to fourth gates 150 communicating with the corners of the second runner 140, and a turbine corresponding to the turbine housing shape made of a dissipation model The housing product shape portion 110 and the independent pressurization portion 160 are prepared (S110).

After the strainer 121 is installed inside the injection cup 120, it is connected to the large diameter portion 131 of the first runner 130, and the first runner 130 is upright in the direction of gravity (S120 ) The small diameter portion of the first runner 130 is arranged to communicate with the central portion of the second runner 140 (S130).

The first to fourth gates 150a, 150b, 150c, and 150d are connected in the order of height in the clockwise direction with respect to the four corners of the second runner 140 (S140).

With respect to the first to fourth gates 150a, 150b, 150c, and 150d, the plurality of turbine housing product-shaped portions 110 are sequentially arranged so that the thin plate sheet portion 145 of the turbine housing product-shaped portion 110 faces each other. It is installed to be offset in the height direction (S150).

The first runner ( 130) so that a positive pressure is formed in the turbine housing product shape portion 110 (S160).

In this way, the mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention is assembled, a ceramic shell mold is formed, charged into a vacuum melting furnace, and predetermined heat-resistant molten metal is injected into the cavity of the ceramic shell mold to form a molten metal. After filling, the turbine housing may be cast through post-processing such as cutting the gate portion.

Hereinafter, a turbine housing precision casting method according to a modified embodiment of the present invention capable of simultaneously casting 8 turbine housings will be described with reference to FIGS. 5 and 6 .

5 and 6, the turbine housing precision casting method according to a modified embodiment of the present invention includes a mold assembly 100 for precision casting of a turbine housing according to an embodiment of the present invention and an embodiment of the present invention Eight turbine housings may be cast by vertically combining the mold assemblies 200 except for the injection cup 120 in the mold assembly 100 for precision casting of the turbine housing according to.

Turbine housing precision casting method according to a modified embodiment of the present invention is only different in that the mold assembly 100 for turbine housing precision casting according to an embodiment of the present invention is coupled in the vertical direction. Since all the technical ideas of the mold assembly 100 for precision casting of the turbine housing according to are included, the differences will be mainly described.

Turbine housing precision casting method according to a modified embodiment of the present invention is the first runner 130 of the first turbine housing precision casting mold assembly 100 and the second turbine housing precision casting mold assembly 200 to the third runner 210 is communicated vertically in the vertical direction so that the molten metal injected through the injection cup 120 of the first turbine housing precision casting mold assembly 100 passes through the third runner 210 to the second turbine housing precision casting It is configured to be filled in the product forming unit 110 of the mold assembly 200 for use.

As such, the turbine housing precision casting method according to the modified embodiment of the present invention includes the first runner 130 of the first turbine housing precision casting mold assembly 100 and the second turbine housing precision casting mold assembly 200 By arranging the three runners 210 to communicate vertically, the molten metal flowing into the first runner 130 can smoothly flow into the third runner 210 due to the increase in pressure due to the height difference of the molten metal.

On the other hand, the third runner 210 of the first runner 130 and the third runner 210 can be formed tapered to have a larger inclination gradient toward the bottom, thereby minimizing air bubble incorporation, and the cross section is circular turbulence of the internal molten metal can be minimized.

Similarly, the turbulence of the molten metal can be minimized by rounding the connecting portion of each gate 150 at the fourth corner of the second runner 140 .

100: mold assembly for precision casting of turbine housing
110: product forming unit 120: molten metal inlet
130, 140: first and second runners 150: gate
210: 3rd runner

Claims (9)

A plurality of product forming parts arranged radially;
A single injection cup disposed at the radial center of the plurality of product molding parts to inject molten metal into the plurality of product molding parts;
A first runner that moves the molten metal injected through the single injection cup vertically downward toward the plurality of product forming units;
A second runner radially branched to move molten metal from the first runner to the plurality of product forming parts, which are spaces in which a turbine housing is formed;
Perpendicular to each of the plurality of product forming parts to provide pressure independent of each other so that molten metal of a certain pressure is injected into the inside of the plurality of product forming parts through the second runner between the first runner and the plurality of product forming parts An independent pusher installed side by side upward but lower than the height of the first runner;
A mold assembly for precision casting of a turbine housing comprising a plurality of gates radially and sequentially arranged with a height difference with respect to the second runner. According to claim 1
A mold assembly for precision casting of a turbine housing in which a strainer is installed inside the single injection cup and a heating sleeve is disposed around the upper surface of the first runner. According to claim 1
The first runner includes a second runner whose lower surface is formed to be tapered in a downward direction and diverges in a direction crossing diagonally from a vertical lower end of the first runner,
The second runner includes a central communication portion with the first runner and a branch portion radially diverging from the central communication portion, the length of the branch portion is the same, and configured to solidify later than the product forming portion Turbine housing mold assemblies for investment casting in According to claim 3,
The plurality of differential gates include a first gate communicating with a first edge of the second runner, a second gate communicating with a second edge, a third gate communicating with a third edge, and a fourth edge communicating with each other. Including a fourth gate,
The first to fourth gates are configured to have a height difference in one direction so as not to interfere with each other in consideration of the phase of the scroll portion of the turbine anti-housing product shape. A plurality of turbine housings are formed by connecting the third runner of the mold assembly for precision casting of another turbine housing vertically downward with respect to the first runner of the mold assembly for precision casting of the turbine housing according to any one of claims 1 to 4. Mold assembly for precision casting of turbine housing that doubles mass production. According to claim 5,
The first runner and the third runner have circular cross-sections, and the downwardly tapered inclination angle of the third runner is greater than the inclination angle at which the first runner tapers downward. In the turbine housing precision casting method using a mold assembly for precision casting of the turbine housing,
An injection cup into which heat-resistant molten metal is injected, a first runner connected to the injection cup, a second runner branched in four directions, and first to fourth gates communicating with corners of the second runner, Preparing a plurality of turbine housing product shapes corresponding to the shape of the turbine housing made of a dissipation model, and independent pushers by the number of the turbine housing product shapes, respectively;
Installing a strainer inside the injection cup, connecting it to the large diameter part of the first runner, and standing the first runner upright in the direction of gravity;
arranging the small-diameter portion of the first runner to communicate with the central communication portion of the second runner;
communicating and coupling the first to fourth gates clockwise with respect to four corners of the second runner in order of height;
Installing a plurality of the turbine housing product shape parts sequentially so as not to interfere in the height direction so that the thin plate sheet parts of the turbine housing product shape face each other with respect to the first to fourth gates;
In the turbine housing product shape, by arranging an independent pressurized portion parallel to the first runner at a position farthest from the thin plate sheet portion so that a positive pressure is formed against the turbine housing product shape with respect to the first runner Turbine housing precision casting method using a mold assembly for precision casting of the turbine housing comprising a. According to claim 7,
The second runner is integrally formed to have a central communication portion connected to the first runner and a plurality of branch portions radially diverging from the central communication portion Turbine housing precision casting using a mold assembly for precision casting of a turbine housing method. According to claim 8,
A plurality of mold assemblies for precision casting of the turbine housing are vertically arranged for mass production, and when a plurality of mold assemblies for precision casting of the turbine housing are vertically arranged, a cross section of the third runner connected to the first runner is circular, and the A turbine housing precision casting method using a mold assembly for precision casting of a turbine housing in which a downwardly tapered inclination angle of a third runner is greater than a downwardly tapered inclination angle of a first runner.

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