JP6331643B2 - Low pressure casting equipment - Google Patents

Description

The present invention is particularly, it relates to low-pressure casting apparatus having a casting sprue member used to fill the molten metal in the mold.

There exists a thing described in patent document 1 as this kind of casting gate member. The gate member described in Patent Document 1 has a structure in which an intermediate layer of porous ceramics is interposed between an inner layer of a sintered body made of a melt resistant material and an outer layer made of a metal material. Further, the upper half of the gate member has a shape in which the opening area increases in the upward direction, and the lower half has a shape in which the opening area increases in the downward direction.

  After filling the mold cavity with the molten metal, the above-mentioned gate member solidifies the molten metal inside the upper part and releases it as a part of the product, while leaving the molten metal inside the lower side unsolidified. By returning to the holding furnace, the yield of the material is improved, and the melt resistance and impact resistance are improved, and the heat retention of the molten metal is improved.

Japanese Patent Laid-Open No. 9-300060

  In the casting using the conventional gate member as described above, it is necessary to wait for the molten metal inside the gate member to solidify when the mold is opened to release the cast product. However, in the conventional gate member, since the heat retention is improved by the multilayer structure, it takes time for the molten metal inside the upper side to solidify, and as a result, the cycle time of casting becomes longer. Since there is a point, it was a problem to solve such a problem.

The present invention has been made paying attention to the above-described conventional problems, and includes a gate member for filling a mold cavity with molten metal in low-pressure casting, and casting without waiting for the molten metal inside the member to solidify. to allow release of the product, and its object is to provide a low-caster that can achieve improvement in yield of the reduction and material of the casting cycle time.

A low-pressure casting apparatus according to the present invention includes a gate member for filling a molten metal into a cavity of the mold between a holding furnace and a mold, and the gate member closes an upper end portion and a lower end portion. a sprue to form a was opened space, and a gate portion for communicating with and the cavity is formed at a position lower than said cavity in said sprue, the sprue portion and the gate portion, of the mold The gate part of the gate member and the mold side gate part provided in the mold are formed between the gate member and the cavity. a structure that has a gate, and a means for solving the conventional problems with the above configuration.

That involved in the present invention the low casting apparatus, by adopting the above configuration, while leading to the cavity of the mold from the gate portion of the sprue portion, becomes Gate, when the molten metal solidifies in the cavity , in the gate, forming a border region of the solidified portion and the non-solidified portion of the molten metal, leaving the majority of the molten metal in the sprue portion of the non-solidified state.

Thus, low casting device, that the interior of the molten metal of the sprue member to enable release of the cast product without waiting for the solidification, to realize an improvement in yield of the reduction and material of the casting cycle time it can.

It is a section explanatory view of the low pressure casting device showing a 1st embodiment of the present invention. It is sectional drawing (A) which shows the gate member in FIG. 1, and the top view (B) of the principal part. It is the top view (A) which shows the front suspension member for motor vehicles which is an example of a casting product, and the bottom view which served as arrangement | positioning of the gate. It is a graph which shows the temperature change of the molten metal of each part with progress of time. It is sectional drawing (A) of the gate member in 2nd Embodiment of this invention, and the top view (B) of the principal part. It is sectional drawing (A) of the gate member in 3rd Embodiment of this invention, and the top view (B) of the principal part.

(First embodiment)
A low pressure casting apparatus 1 shown in FIG. 1 includes a base 2, a plurality of guide posts 3 erected on the base 2, a stationary platen 4 fixed between the guideposts 3, and between the stationary platen 4 and the base 2. A holding furnace 5 is provided. The casting apparatus 1 includes a movable plate 6 that is driven up and down along the guide post 3 and a frame 7 that is installed on the upper end of the guide post 3. The frame 7 includes a hydraulic cylinder that drives the movable plate 6 up and down. 8 is provided. Further, the low pressure casting apparatus 1 includes a mold 9 between the movable platen 6 and the fixed platen 4.

  The holding furnace 5 contains the molten metal M, and is provided with a lid body 5A combined on the lower side of the fixed platen 4, a heating means (not shown) (not shown), and the like. A stalk 10 for supplying the molten metal M to the cavity 9C is provided. The stalk 10 communicates with the gate member 15 which will be described later at the upper end portion, and the lower end portion is immersed in the molten metal M.

  The mold 9 includes an upper mold 9U disposed on the movable platen 6 and a lower mold 9L disposed on the fixed platen 4, and a cavity 9C serving as a casting space is formed therebetween. The upper mold 9U includes an extrusion plate 12 that can be moved up and down between a mold holder 11 fixed to the movable platen 6 and a mold main body (9U) that forms a cavity 9C. The extrusion plate 12 includes a plurality of springs 13 interposed between the mold body (9U) and a plurality of extrusion pins 14 penetrating the mold body (9U).

As shown in FIG. 1, when the mold 9 is closed, the extrusion plate 12 forms a gap with the mold body (9U) by the spring 13, and the tip of each extrusion pin 14 is located on the mold body (9U). Immersive to the bottom. The pushing plate 12 is prevented from rising by a stopper (not shown) in the middle of the ascending process of the movable plate 6 by the contraction drive of the hydraulic cylinder 8, and then the movable plate 6 is raised while compressing the spring 13. While reaching the limit, the tip of each push pin 14 protrudes from the bottom surface of the die body (9U) to release the cast product.

  The lower mold 9L of the mold 9 is provided with a casting gate member (hereinafter simply referred to as a “gate member”) 15 for filling the cavity 9C with the molten metal of the holding furnace 5 in low pressure casting. The gate member 15 will be described in detail later. Further, the low pressure casting apparatus 1 controls the pressurizing means 16 for pressurizing the inside of the holding furnace 5 with gas, the decompression means 17 for sucking and exhausting the inside of the cavity 9C of the mold 9 and depressurizing them. And control means (not shown).

  The pressurizing means 16 includes a tank that stores a pressurizing gas such as an inert gas, and a supply pipe 16A that communicates from the tank to the holding furnace 5, and an adjustment valve 16B that opens and closes the flow path is provided in the middle of the supply pipe 16A. It is provided. The pressurizing means 16 pressurizes and supplies gas into the holding furnace 5 to apply pressure to the surface of the molten metal M, thereby supplying the molten metal M to the cavity 9C through the stalk 10 and the gate member 15.

Decompression means 17, a vacuum tank 17C having an exhaust pipe 17B into and exit side has an intake pipe 17A on the inlet side, and a vacuum pump 17D connected to an exhaust pipe 17B of the vacuum tank 17C, the intake pipe 17A An on-off valve 17E that opens and closes and a filter 17F are provided. In addition to the pressurizing unit 16 and the decompressing unit 17, the control unit controls the operation of the hydraulic cylinder 8 that drives the movable plate 6 up and down.

  As shown in FIG. 2, the gate member 15 is provided between the upper die 9U and the lower die 9L, and has a gate portion 15A and a gate portion 15B. The gate portion 15A and the gate portion 15B are It is made of a material having a heat insulating property higher than that of the mold 9.

  The gate portion 15 </ b> A forms a space in which the upper end portion is closed and the lower end portion is opened, and the lower end portion communicates with the stalk 10 of the holding furnace 5. The gate portion 15A in the illustrated example has a generally truncated cone shape with an opening area increasing downward.

  The gate portion 15B is formed at a position lower than the cavity 9C on the side of the gate portion 15A and communicates with the cavity 9C. The gate portion 15B is formed on the mating surface of the mold 9 (the mating surface of the upper mold 9U and the lower mold 9L), and the cavity 9C is passed through the mold-side gate portion 9G formed on the mating surface portion. Communicating with

The gate portion 15B of the gate member 15 and the mold side gate portion 9G communicate with each other to form an inclined gate (gate) G having an upward slope toward the cavity 9C. Further, the sprue portion 15A, by providing the gate portions 15B to the mating surface of the mold 9 in which the sides thereof, the upper portion is formed in the upper mold 9 U than the gate portion 15B, this upper The trap space 15C accommodates the oxide film on the surface of the molten metal.

  Furthermore, the gate member 15 of this embodiment is formed by a coating mold in which a material having a heat insulating property is applied to a predetermined thickness on the inner walls of the hollow portions of the upper mold 9U and the lower mold 9L and cured. Yes. Examples of the material of the gate member 15 include well-known foundry sand, ceramics, heat-insulating fibers, and a binder for binding them.

  FIG. 3 is a view showing an automotive front suspension member SM as an example of a cast product manufactured by the low-pressure casting apparatus 1 described above. The suspension member SM is a skeletal member for connecting an automobile body and axle and simultaneously loading an engine. The illustrated example includes a front cross member portion M1, a rear cross member portion M2 on the body side, The left and right side member portions M3 and M3 are integrally provided. The suspension member SM is made of, for example, an aluminum alloy.

  In addition, the suspension member SM has a hollow shape (closed cross-section structure) between the cross member portions M1 and M2 and the cross member portions M1 and M2 of the side member portion M3. For forming this hollow portion, a core disposed in the cavity 9C is used. Such a suspension member SM realizes strength improvement and weight reduction, and is thin and relatively large as a casting.

  Furthermore, the suspension member SM has a large number of ribs R for ensuring strength, particularly on the bottom surface shown in FIG. 3B, and is cast with the bottom surface facing upward. That is, in the low pressure casting apparatus 1, the contact area between the upper die 9U and the suspension member SM becomes larger than the contact area between the lower die 9L and the suspension member SM by making the bottom surface having the rib R upward. Like that. As a result, the low-pressure casting apparatus 1 allows the suspension member SM to be attached and held on the rising upper mold 9U when the mold 9 is opened, and facilitates the subsequent removal work of the suspension member SM.

  Furthermore, when the cast product is the suspension member SM, the low-pressure casting apparatus 1 arranges a plurality of gate members 15 as shown in FIG. 3B. 3 (A) and 3 (B) are a plan view and a bottom view of the suspension member SM, but the cavity 9C of the mold 9 has the same shape. The arrangement is illustrated.

  The low-pressure casting apparatus 1 having the above-described configuration is configured to pressurize and supply gas into the holding furnace 5 by the pressurizing means 16 after closing the mold 9, and the stalk 10, the gate member 15, and the inclined gate are generated by the pressure. The molten metal M is pressurized and filled into the cavity 9C through G. At this time, the inside of the cavity 9C is sucked and exhausted by the decompression means 17 so that the cavity 9C is filled with the molten metal M more quickly.

  Thereafter, when the molten metal M in the cavity 9C has solidified, the low pressure casting apparatus 1 raises the upper mold 9U together with the movable plate 6 by the contraction drive of the hydraulic cylinder 8, and opens the mold 9. At this time, the low-pressure casting apparatus 1 has an inclined gate G composed of the gate portion 15B of the gate member 15 and the mold-side gate portion 9G between the gate member 15 and the cavity 9C. Since it is formed of a material having a heat insulating property higher than the heat insulating property of the mold 9, the temperature of the molten metal M (aluminum temperature) in each part is different as shown in FIG. 4.

  That is, the melt temperature of the gate portion 15B is slightly lower than the melt temperature in the spout portion 15A of the spout member 15, while the melt temperature of the communicating portion between the mold side gate portion 9G and the cavity 9C is Significantly lower. For this reason, when the molten metal M in the cavity 9C is solidified, the low-pressure casting apparatus 1 increases the proportion of the molten metal M that is unsolidified as it approaches the gate portion 15A. In the vicinity, a boundary region between the solidified portion and the unsolidified portion of the molten metal M is formed. At this time, most of the molten metal M in the gate portion 15A remains in an unsolidified state.

  Therefore, as shown in FIG. 4, the low pressure casting apparatus 1 stops the pressurization in the holding furnace 5 by the pressurizing means 16, and when the molten metal M in the cavity 9C is solidified, the mold 9 is opened. The unsolidified molten metal M in the gate part 15A is dropped into the holding furnace 5. The molten metal solidified in the mold side gate portion 9G is integrated with the cast product (suspension member SM) and released from the lower mold 9L. In this way, the gate member 15 and the low-pressure casting apparatus 1 using the same enable the casting product to be released without waiting for the molten metal M in the gate member 15 to solidify, and shorten the casting cycle time. And the yield of materials can be improved.

  Moreover, the above-described gate member 15 has an extremely simple structure and can be obtained at a low cost as compared with a member having a conventional multilayer structure. Further, the gate member 15 has a gate portion 15B at a position lower than the cavity 9C, thereby forming an inclined gate G having an upward slope on the cavity 9C side in the low-pressure casting apparatus 1, and in particular. The mold releasability of the solidified shell in the mold side gate portion 9G is improved, and defects such as galling to the lower mold 9L and remaining pouring gate can be eliminated.

  Furthermore, since the above-mentioned pouring gate member 15 has a shape in which the opening area of the pouring gate portion 15A increases in the downward direction, the unsolidified molten metal M easily falls into the holding furnace 5 and the hot water runs out better.

  Furthermore, the above-described pouring gate member 15 is formed by forming the upper portion of the pouring gate portion 15A into the trap space 15C. The coating is allowed to enter the trap space 15C, and the oxide coating is prevented from flowing out from the gate portion 15B toward the cavity 9C. Thereby, it is possible to prevent the occurrence of casting defects due to the inclusion of the oxide film.

  5 and 6 are views for explaining second and third embodiments of the gate member according to the present invention. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

(Second Embodiment)
The gate member 25 shown in FIG. 5 has a gate portion 25A, a gate portion 25B, and a trap space 25C, and the gate portion 25A and the gate portion 25B are formed of a material having a heat insulating property higher than that of the mold 9. In this embodiment, it is a block-shaped sand mold. In addition, the gate portion 25B of the gate member 25 forms an inclined gate G having an upward slope on the cavity 9C side together with the mold side gate portion 9G.

Even in the above sprue member 25, can be applied to low-caster 1 shown in FIG. 1, as in the previous embodiment, the structure is simple, member inside the molten metal M is solidified Therefore, it is possible to release the cast product without waiting for it to be performed, and it is possible to shorten the casting cycle time and improve the material yield.

  In addition, since the gate member 25 of this embodiment is made of a block-shaped sand mold, the gate portion 25B has a large length so that the solidified portion and the unsolidified portion of the molten metal M are in the inclined gate G. The boundary area is easily formed. Thereby, the pouring gate member 25 can return most of the molten metal M in the pouring gate portion 25B to the holding furnace 5 while remaining in an unsolidified state, and can contribute to further improvement of the material yield.

  In addition, the gate member 25 described above has good mold releasability of the solidified shell in the mold side gate portion 9G, eliminates defects such as galling to the lower mold 9L and the remaining gate, and the gate portion 25A. The lack of hot water becomes better. Furthermore, the above-described gate member 25 prevents the oxide film from flowing out toward the cavity 9C by the trap space 25C and prevents the occurrence of casting defects due to the inclusion of the oxide film.

(Third embodiment)
The gate member 35 shown in FIG. 6 has a gate portion 35A, a gate portion 35B, and a trap space 35C, and the gate portion 35A and the gate portion 35B are formed of a material having a heat insulating property higher than that of the mold 9. It is. Moreover, the gate member 35 of the example of illustration consists of the upper side member 35U and the lower side member 35L which formed the heat insulating material in the block shape.

  The upper member 35U forms a trap space 35C and is incorporated in the upper mold 9U of the mold 9. The upper member 35L forms a gate portion 35A and is incorporated in the lower lagoon 9L of the mold 9. And the gate member 35 is made up of the upper and lower members 35U. A gate portion 35B is formed between 35L.

  As described above, the heat insulating material that forms each of the members 35U and 35L includes ceramics, heat insulating fibers, a binder that binds these, and the like. Further, the gate portion 35B of the gate member 35 forms an inclined gate G having an upward slope toward the cavity 9C side together with the mold side gate portion 9G.

Even in the above sprue member 35, can be applied to low-caster 1 shown in FIG. 1, as in the previous embodiment, the structure is simple, member inside the molten metal M is solidified Therefore, it is possible to release the cast product without waiting for it to be performed, and it is possible to shorten the casting cycle time and improve the material yield. Further, since the gate member 35 is formed by forming a heat insulating material in a block shape, the length of the gate portion 25B is ensured to be large, and the boundary between the solidified portion and the unsolidified portion of the molten metal M in the inclined gate G is ensured. This makes it easier to form regions and contributes to further improvement in material yield.

  Furthermore, the above-described gate member 35 has good releasability of the solidified shell in the mold-side gate portion 9G, eliminates defects such as galling to the lower mold 9L and remaining gate, and the gate portion 35A. The lack of hot water becomes better. Further, since the gate member 35 including the upper member 35U and the lower member 35L is formed, the gate member 35 is also separated into the upper and lower portions together with the opening of the mold 9, and does not stick to the upper die 9U. Further, the gate member 35 prevents the oxide film from flowing out toward the cavity 9C by the trap space 35C, and prevents the occurrence of casting failure due to the inclusion of the oxide film.

  In addition, the structure of the molten metal inlet member and the low-pressure casting apparatus using the same according to the present invention is not limited to the above-described embodiments, and the details of the structure are appropriately changed without departing from the gist of the present invention. It can be applied to the manufacture of various cast products.

DESCRIPTION OF SYMBOLS 1 Low pressure casting apparatus 5 Holding furnace 9 Mold 9C Cavity 9G Mold side gate part 15, 25, 35 Gate member 15A, 25A, 35A Gate part 15B, 25B, 35B Gate part 15C, 25C, 35C Trap space G Inclined gate M Molten metal

Claims (4)

Between the holding furnace and the mold, a gate member for filling the molten metal into the mold cavity ,
The sprue member has a sprue forming a space opens the occluded and the lower end of the upper portion, and a gate portion communicating with and the cavity is formed at a position lower than said cavity in said sprue ,
The sprue portion and the gate portion, with is formed of a material having a high heat insulating property than the thermal insulating properties of the mold,
Wherein between the sprue member and the cavity, a low pressure casting apparatus is characterized that you have a gate composed of the gate portion and the molds provided mold side gate part of the sprue member. The low-pressure casting apparatus according to claim 1, wherein the gate portion has a shape in which an opening area increases in a downward direction. The low-pressure casting apparatus according to claim 1 or 2, wherein the gate portion is provided on a side portion of the gate portion, and an upper portion of the gate portion is a trap space for accommodating an oxide film on the surface of the molten metal. . The low-pressure casting apparatus according to any one of claims 1 to 3, wherein the gate member is a block-shaped sand mold.

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