JPH08282295A - Die-casting door panel and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a die-casting door to be assembled to a window of an automobile and a train or the like. CONSTITUTION: The melted alloy 30 is filled into a casting space 14 from gates 37, 38, which are opened in the abutment surface with a movable die 13, through second runners 35, 36 extended from a first runner 23, which is provided in the abutment surface of a fixed die 11 and an intermediate die 12, passing through the intermediate die 12, by the pressurization so as to cast a large and thin integral inner panel. This inner panel is pinched in a hemmed peripheral part of an outer panel, and bonded by the spot welding and the welding agent or the like so as to unify the inner panel and the outer panel. The inner panel having the complex shape can be thereby manufactured as an integrated material by the die-casting, and a light die-casting door, which has the necessary strength when it is combined with the outer panel, is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door panel for automobiles, trains, etc., which is required to be lightweight and strong, and a method for manufacturing the same.

[0002]

2. Description of the Related Art When a panel such as a door having a large area is made of an aluminum material or the like, it is difficult to integrally form the panel,
Each part was divided and press molded to assemble each molded part. When a door is attached to the body of an automobile or train, excessive force is applied to the pivot and its vicinity.
Therefore, a thick aluminum plate is press-molded at a portion where a large load is applied, and is welded to a press-molded product made of another thin plate.

[0003]

In the conventional method, it is necessary to press-mold each part and assemble each of the divided parts, which requires a lot of man-hours and causes an increase in manufacturing cost. Moreover, since the shape of the mold differs for each product, it is required to prepare a large number of molds. Moreover, since the portions having different plate thicknesses are welded for reinforcement, not only the welding process is required, but also the shape of the obtained door panel is restricted. As a result, it is not possible to meet the demand for products having various shapes. The present invention has been devised to solve such a problem, and by adopting a die casting method capable of freely changing the wall thickness, the number of man-hours and press die costs can be reduced or reduced, and the design The purpose is to obtain a die-cast door having a high degree of freedom and having an arbitrary shape at low cost.

[0004]

In order to achieve the object, the manufacturing method of the present invention includes a second runner extending from a first runner provided on a mating surface of a fixed die and an intermediate die through the intermediate die. After passing through the runner of, through the gate opened on the mating surface with the movable mold, the outer panel is sandwiched by hem processing on the peripheral part of the large-sized thin-walled inner panel obtained by pressure-injecting the molten alloy into the casting space. The feature is that the inner panel and the outer panel are integrated by joining them by spot welding, bonding, etc. The gate provided in the intermediate type is
At least one distribution is provided in a circle whose diameter is 50 to 100 times the product thickness of the inner panel. In particular, in the part of the casting space corresponding to the thick part of the inner panel,
It is preferable to provide a dedicated gate. An impact beam for reinforcement is interposed between the inner panel and the outer panel as needed. Considering safety, the inner panel is 1.5 to 3.0 compared to the rear side of the vehicle front side.
It is preferable to double the thickness.

The obtained inner panel has a thickness of 1.5 to 3 m.
Despite being a shape with an extremely large area compared to a thin plate thickness of about m, it has no casting defects such as lack of meat, poor fusion, poor shape, etc. and exhibits strength comparable to conventional steel products. Therefore, the weight of the vehicle can be significantly reduced. The inner panel may be partially thickened, and reinforcing ribs, ribs communicating with the belt line portion in the vehicle front-rear direction, ribs communicating with the window regulator attachment portion, and the like may be integrally provided. These ribs are provided in a substantially trapezoidal cross section having a height of 30 mm or less and an upper side length of 15 mm or less in consideration of the occurrence of defects such as sink marks during die casting. An aluminum alloy or a magnesium alloy is used as the alloy cast on the inner panel. The aluminum alloy contains Si: 3 to 12% by weight, Fe: 0.3 to 2.0% by weight, Mg: 0.1 to 1.0% by weight, and Mn: 0.3 to.
Those containing 1.0% by weight are used. As the magnesium alloy, one containing Al: 2.0 to 7.0 wt% is used. As the outer panel integrated with the inner panel, an outer panel processed into a good surface state by press molding is used.

After the die casting, when any one of the heat treatments (1) to (3) is performed, the mechanical properties in the as-cast state are improved. These heat treatments promote the refinement and spheroidization of eutectic Si and improve the elongation by 3% or more. After keeping at a temperature of 300 ° C. or higher for 1 hour or longer, it is allowed to cool. Hold at 450 to 550 ° C for 10 minutes or more and then quench. After keeping at 130 to 250 ° C. for 1 to 5 hours, it is allowed to cool. After holding at 450 to 550 ° C. for 10 minutes or more, it is rapidly cooled, and further held at 100 to 250 ° C. for 1 to 5 hours and allowed to cool. The door panel according to the present invention is die cast using, for example, the mold shown in FIG. Mold 10 is fixed mold 1
1, the intermediate mold 12 and the movable mold 13 are combined, and a casting space 14 corresponding to the product shape is formed between the intermediate mold 12 and the movable mold 13. Fixed type 11, intermediate type 12
The movable mold 13 includes a fixed platen 21 and a movable platen 2.
It is sandwiched between two. Movable die 13 and movable platen 22
The die base 23 is inserted between and.

The molten alloy 30 to be cast is housed in a sleeve 32 whose one end is closed by a plunger 31. The other end of the sleeve 32 is open to the spool 33 formed on the fixed mold 11. The spool 33 is a fixed type 11
Through the first runner 34 formed in the intermediate die 12 and the second runners 35, 36 and the gates 37, 38 formed in the intermediate mold 12 to communicate with the casting space 14. The molten alloy 30 is pressurized by the plunger 31, and is pressed into the casting space 14 from the plurality of gates 37, 38, ... Through the runners 34 to 36. The molten alloy 30 is cooled and solidified in the casting space 14 by the mold 10. When the cast molten alloy 30 is cooled to a predetermined temperature, the extrusion pins 39, 39 ... Are extruded from the die base 23 side toward the casting space 14 to separate the cast aluminum alloy product from the die 10.

In the casting using the die 10 composed of the fixed die 11, the intermediate die 12 and the movable die 13 as described above, the molten alloy is cast through the runners 34 to 36 penetrating the fixed die 11 and the intermediate die 12. The aluminum alloy die casting is separated from the mold 10 by the extrusion pins 39, 39, ... Which are supplied to the space 14 and are extruded from the other side. Therefore, even if the target shape has a larger area than the thickness, the molten metal can be supplied to the central portion of the casting space 14, and a sufficient amount of molten metal is filled in each portion. As a result, compared to the die-casting die design of the two-die die that supplies the molten alloy from the side surface of the product, there are less restrictions on the shape of the product to be cast, and a cast product having a large area can be easily manufactured. In addition, the runner 35 is used in the thickened portion for reinforcement.
By providing a dedicated runner on the intermediate die 12 as shown by the gate 37, a thick portion having a required thickness can be easily formed.

Molten alloy melt 3 cast using this mold
As 0, an aluminum alloy or a magnesium alloy is used. Aluminum alloys have Si: 3 to 12% by weight, Fe: 0.3 to 2.0% by weight, Mg: 0.1 to
An aluminum alloy containing 1.0% by weight and Mn: 0.3 to 1.0% by weight, or an aluminum alloy further containing Cu: 1.0 to 5.0% by weight is used. As the magnesium alloy, one containing Al: 2.0 to 7.0 wt% is used. The components of the aluminum alloy affect the properties of the cast product obtained as follows. Si: 3 to 12% by weight It is an alloying element that affects the castability, and if 3% by weight or more of Si is contained, good melt flowability can be obtained. However, a large amount of Si content exceeding 12% by weight promotes crystallization of primary crystal Si and tends to reduce the toughness of the obtained cast product.

Fe: 0.3-2.0% by weight Fe is an effective element for improving the separability of the cooled and solidified cast product from the inner surface of the mold 10. Fe content 0.3% by weight
If less than, seizure easily occurs on the inner surface of the mold 10,
The separability is lowered and surface defects are easily generated in the obtained cast product. However, a large amount of F exceeding 2.0% by weight
When e is contained, a huge Fe-based intermetallic compound is likely to be generated, which lowers the toughness of the cast product. Mg: 0.1-1.0 wt% Mg ₂ Si is deposited on the aluminum matrix and improves the strength of the cast product. This effect is
It becomes remarkable when the g content is 0.1% by weight or more. But,
When the Mg content exceeds 1.0% by weight, the fluidity of the molten metal is lowered, and defects such as lack of meat are likely to occur.

Mn: 0.3 to 1.0 wt% A granular Al-Fe-Mn-based intermetallic compound is formed together with Fe to improve the toughness of a cast product. However, Al-Fe
If the Mn content is less than 0.3% by weight, the —Mn-based intermetallic compound does not exhibit a sufficient granulation effect. Further, if a large amount of Mn exceeding 1.0 wt% is contained, a huge massive Al
A -Fe-Mn-based intermetallic compound is generated, which causes a hard spot. Cu: 1.0 to 5.0% by weight It is an alloying element added as necessary, and has an effect of improving mechanical strength such as proof stress. Such an effect is
It becomes remarkable when the Cu content is 1.0% by weight or more. But,
When a large amount of Cu exceeding 5.0% by weight is contained, elongation and corrosion resistance tend to deteriorate. On the other hand, as the magnesium alloy, one containing Al: 2.7 to 7.0 wt% is used. Al is an alloying element that affects the castability and mechanical properties of magnesium alloys, and when the content is 2.0 wt% or more, the castability and mechanical strength are improved.
However, when a large amount of Al exceeding 7.0% by weight is contained, elongation, impact value, etc. deteriorate.

In the mold 10 having the structure shown in FIG. 1, the reinforcing thick portion can be easily formed. However, when considering shrinkage when the cast product solidifies and cools, various casting defects are likely to occur in the thick portion where cooling is likely to be delayed. For this reason, it is preferable that the thick portion is formed by a rib having a size that takes into consideration the prevention of the occurrence of a sink. It is also an effective means to incorporate a chill material in the thick portion to make the cooling conditions of each portion uniform. The casting space 14 is designed according to the product shape. For example, when the product shape has a plurality of windows 51, 51, ... As shown in FIG. 2 (a), an intermediate mold is formed at a position corresponding to the windows 51, 51 .. 12 and the movable mold 13 are brought into close contact with each other.
Since the edge portions of the window portions 51, 51, ... Are insufficient in strength, the ribs 40 are formed so as to surround the window portions 51, 51. The rib 40 continuous in this way can be formed by, for example, a groove formed on the surface of the movable die 13 in contact with the intermediate die 12. In addition, the intermediate mold 12 and the movable mold 13
When the contact surface with is curved, the cross-sectional shape is
A product having a curved surface of a predetermined shape is obtained as shown in (b).

In die casting of products having a large area,
It is necessary to spread a sufficient amount of molten alloy to each part. In particular, when a cast product having many relatively thin portions is manufactured as shown in FIG. 2, the amount of molten metal supplied to the thin portion is insufficient, and defects such as wall thickness variation and defective shape are likely to occur in the product. In the present invention, the gate 37 for supplying the molten metal to the thick wall portion and the gate 38 for supplying the molten metal to the thin wall portion are distributed as shown in FIG. In order to secure a sufficient molten metal supply amount in each part, according to the experiments by the present inventors, the gate gap is set to a plate thickness of 50-100.
I found it necessary to double. That is, the plate thickness of 5
When at least one gate is provided in a circle having a diameter of 0 to 100 times, a sufficient amount of molten metal is supplied to each part. Specifically, the gate gap is 1 near the plate thickness of 2 mm.
Radius 50 to 100 mm so that it is from 00 to 200 mm
Provide at least one gate within the circle. As a result, a cast product having no defects such as lack of meat or defective shape can be obtained,
The mechanical characteristics are improved. If the number of gates is set to be larger than the above-mentioned experimental value, that is, if the gate interval is made small, the hot water supply is sufficient, but the die design becomes complicated, which is not economical. On the other hand, if the gate interval is too wide, the amount of heat removed from the molten metal by the mold increases as the molten metal moving range increases. As a result, the temperature of the molten metal is lowered, and the molten metal is insufficiently supplied due to the increase in the viscosity of the molten metal, and casting defects such as wrinkles and boundaries are likely to occur.

The obtained cast product may be used as it is, but in consideration of the performance required depending on the application, the heat treatments 1 to 3 are performed as necessary. This is an annealing treatment in which the temperature is kept at 300 ° C. or higher for 1 hour or more and then allowed to cool, and although the tensile strength and the yield strength are reduced, the elongation is improved. To obtain sufficient elongation, a heating temperature of 300 ° C. or higher and a holding time of 1 hour or longer are required. This is a treatment in which the alloy components are solid-solved in an aluminum matrix, which is held at 450 to 550 ° C. for 10 minutes or more and then rapidly cooled. This treatment softens the cast product, lowers the tensile strength and increases the elongation. A heating temperature of 450 ° C. or higher is required to form a solid solution of the alloy components, but a heating temperature of higher than 550 ° C. may cause local melting. Further, if heated for less than 10 minutes, solid solution formation does not proceed sufficiently.

This is a heat treatment for enhancing the strength by forcibly precipitating the solid-dissolved alloy elements by die casting. By holding at 130 to 250 ° C. for 1 to 5 hours and then allowing to cool, the tensile strength and yield strength of the material are improved.
If the heating temperature is lower than 130 ° C. and the heating time is shorter than 1 hour, a sufficient precipitation reaction cannot be obtained. However, 250 ° C
On the contrary, if the heating temperature exceeds 5 hours or the heating time exceeds 5 hours, the softening phenomenon due to overaging tends to occur. 450 to 550 ° C. × 10 minutes or more → Temperature-quenched solution treatment is followed by artificial aging at 100 to 250 ° C. × 1 to 5 hours, which is a heat treatment for precipitating solid solution alloy elements by solution treatment. By this heat treatment, the elongation is slightly lowered, but the tensile strength and the yield strength are increased.

In this way, even if the shape is thinner than the area, the molten alloy is sufficiently supplied to each part, so that there is no casting defect such as lack of thickness, poor fusion, poor shape, etc. Is obtained. The inner panel is integrated with the outer panel to form a vehicle door panel.
As the outer panel, 5000 series such as 5182, 6
A 6000 series such as 111 is molded by press molding and has good surface properties. The outer panel has a slightly larger size than the inner panel. By the hemming, as shown in FIG. 4A, the peripheral edge portion 61 of the outer panel 60 is bent inward by the hemming. The outer panel 60 is replaced with the inner panel 70 (see FIG. 4) manufactured by the die casting method described above.
Combine with b). That is, as shown in FIG. 4C, the peripheral edge portion 61 is folded into the peripheral edge portion 71 of the inner panel 70 by hem processing, and spot welding 72,
Fix both with an adhesive or the like.

Outer panel 60 and inner panel 70
When assembling with, the impact bar 73 is arranged at an appropriate place. A hollow material made of 7000 series aluminum alloy is used for the impact bar 73, and is fixed to the inner panel 70 side by welding or the like. The assembled door is lightweight because it is made of aluminum. Further, since the rigidity is increased by the ribs provided on the inner panel 70, the impact bar 73, and the like, and the surface rigidity is improved by attaching the outer panel, it is possible to sufficiently provide the characteristics required as a structural material for automobiles and the like. ing. This door is attached to the vehicle body by a hinge 62 provided at an appropriate position.

[0018]

【Example】

Example 1: Castings having various wall thicknesses were manufactured by using dies having different gate intervals. Then, the appearance of the cast product was observed, and a product having no casting defects such as poor fusion and lack of meat was evaluated as ◯. When the influence of the gate interval on the casting defect was investigated, as shown in Table 1, in the case of using the mold in which the gate interval / plate thickness ratio was set in the range of 50 to 100 according to the present invention, the occurrence of casting defect occurred. Was not detected. On the other hand, when the gate interval / plate thickness ratio exceeds 100, defects such as defective fusion and insufficient meat were detected in all cases. On the other hand, those having less than 50 are all good without any defects, but are too uneconomical in terms of mold design because there are too many gates.

[0019]

Example 2: An inner panel having a shape shown in FIG. 2 (a) on the back surface and a shape shown in FIG. 2 (b) on the side surface was cast using a three-piece mold. The target size of the inner panel is 1284 mm in length, 593 mm in width and 170 mm in height.
Therefore, it has a shape having a plurality of windows. Each gate 37, 38
· Mold 10 of Figure 1 was designed cross-sectional area 600 mm ² of
Was used to heat the mold 10 to 190 ° C. Regarding the gate position, the gate was provided directly on the product part with the distribution shown in FIG. The distance between adjacent gates is 23 to 162 depending on the product thickness.
It was changed in the range of mm. That is, maximum radius 162m
A total of 43 gates were opened in the casting space with a distribution in which one gate exists in the range of m and the minimum radius of 23 mm.
As a molten alloy to be cast, Si: 9.0% by weight, F
e: 0.47% by weight, Mn: 0.34% by weight and Mg:
Sleeve 32 made of aluminum alloy containing 0.27% by weight
Housed in. The molten aluminum alloy was pressurized by the plunger 31 entering the sleeve 32 at a moving speed of 1.8 m / sec so that the casting pressure was 600 kgf / cm ^2, and was passed through the gates 37 and 38 at a flow velocity of 70 m / sec. In this way, the molten aluminum alloy is cast at a temperature of 690 ° C.
Cast in.

After the cast aluminum alloy had cooled, the casting was removed from the mold 10. When the obtained cast product was observed, no casting defects such as lack of thickness or defective shape were observed in both the thick wall portion and the thin wall portion. And
After casting, a solution treatment was performed at 510 ° C. for 1 hour, and a test body 1 whose elongation was improved by air cooling and a test body 2 as-cast without heat treatment were prepared. From the obtained cast door inner panel substantive product, the material properties of the test pieces collected at the positions shown in FIG. 5 were investigated. As can be seen from the survey results in Table 2, in the as-cast specimen 2, the lower flat plate portion had a low average value of 1.7%. On the other hand, 5 for castings
Specimen 1 which was subjected to solution treatment at 10 ° C. for 1 hour and air-cooled
On the other hand, the growth rate increased significantly, showing a minimum growth rate of 3.6%.

These obtained inner panels were made into 500
In combination with an outer panel made of 0 series aluminum alloy, we made a vehicle door. This door was comparable in strength to conventional steel doors, and could be sufficiently incorporated into a vehicle as a door that was lightweight.
FIG. 6 is a graph showing a load-displacement curve obtained by incorporating the side door into a vehicle body and applying a load from the side. Specimen 1 according to the present invention exhibited strength properties comparable to steel doors, as shown in FIG. On the other hand, in the test body 2 in which the cast body was not heat-treated and the elongation was insufficient, there were inflection points a and b at which the load drastically decreased, and cracks were generated in the cast body at the inflection points a and b. It was It is considered that this is because the cast body has insufficient elongation. Specimen 1 improved in elongation to 3% or more by heat treatment of 510 ° C. × 1 hour → air cooling
Then, it can be seen that the cast product has no such cracking and has a strong proof stress.

These test bodies were about 30% lighter in weight than steel, and the torsional rigidity was about three times that of steel doors. Similarly, Al:
When an inner panel was cast from a magnesium alloy containing 6.0% by weight, defects such as lack of meat and defective shape were not observed in the castable product in the case of using the mold having the gate distribution according to the present invention. It was The door obtained by combining with the outer panel had sufficient strength for vehicles.

[0024]

[0025]

As described above, according to the present invention, a large-sized thin-walled integrated inner panel die-cast by using a three-die mold is combined with an outer panel for a vehicle such as an automobile or a train. It's a door. Since die casting uses a die that is a combination of a fixed die, an intermediate die, and a movable die, even if it is a cast product that has a large area compared to the thickness, products that do not have defects due to lack of meat, etc. It can be obtained with a high degree of design freedom. In addition, since the reinforcing ribs that do not contain defects such as sinkholes are integrally molded, the number of man-hours is greatly reduced compared to the conventional door panel where thick members are assembled by welding etc., and the strength as a structure is improved. Also improves.

[Brief description of drawings]

1 is a cross-sectional view of a mold device for manufacturing a door panel according to the present invention.

FIG. 2 is a rear view (a) and a side view (b) of the die-cast inner panel.

FIG. 3 is an explanatory view showing a position of a gate of the inner panel.

FIG. 4 is a front view (a) of the outer panel, a front view (b) of the inner panel, and a cross-sectional view (c) showing a connecting portion between the two.

FIG. 5 is a view showing a test piece sampling position of a cast door inner panel actual product manufactured in an example.

FIG. 6 is a graph showing a load-displacement curve of the side door manufactured in the example.

[Explanation of symbols]

10: Mold 11: Fixed type 12: Intermediate type 1
3: Movable type 14: Casting space 21: Fixed platen 22: Movable platen 30: Molten alloy 31: Plunger 32: Sleeve 33: Sprue 34: First runner 35, 36: Second runner 37-38: Gate 39 : Extrusion pin 40: Rib 51: Window part 60: Outer panel 61: Hem-processed peripheral part 62: Hinge 70: Inner panel 71: Peripheral part 72: Spot welding 73: Impact bar

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Watanabe 3-13-12 Mita, Minato-ku, Tokyo Within Japan Light Metals Co., Ltd. (72) Inventor Katsuya Nishiguchi 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Inventor Yukio Yamamoto No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Yukihiro Sugimoto No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (10)

[Claims] 1. A first runner provided on a mating surface between a fixed mold and an intermediate mold, a second runner extending through the intermediate mold, and a gate opening on a mating surface with the movable mold. A die casting characterized in that the inner panel and the outer panel are integrated by sandwiching the outer panel by hem processing and joining it to the peripheral edge of the large-sized thin-walled inner panel obtained by pressurizing the molten alloy into the casting space. Door panel and manufacturing method thereof. 2. The product thickness of the inner panel is 50 to 10
The die-cast door panel according to claim 1, and a method of manufacturing the same, wherein an intermediate mold having at least one gate provided in a circle having a diameter of 0 times is used. 3. The die cast door panel according to claim 1, wherein the intermediate die is provided with a gate in a portion of the casting space corresponding to the thick portion of the inner panel, and the method for producing the door panel. 4. The die-cast door panel according to claim 1, wherein an impact beam is provided between the inner panel and the outer panel, and a method for producing the door panel. 5. The front side of the vehicle body is 1.5 to 1.5 times larger than the rear side.
The die-cast door panel according to any one of claims 1 to 4, wherein an inner panel having a thickness of 3.0 times is cast, and a method for producing the door panel. 6. Si: 3 to 12% by weight, Fe: 0.3 to
2.0 wt%, Mg: 0.1-1.0 wt% and Mn:
The die-cast door panel according to any one of claims 1 to 5, and a method for manufacturing the same, wherein an aluminum alloy containing 0.3 to 1.0% by weight is cast on the inner panel. 7. The inner panel is cast with a magnesium alloy containing Al: 2.0 to 7.0% by weight.
A door panel made of die-cast according to any one of 1. 8. The die-cast door panel according to any one of claims 1 to 7, wherein a press-molded outer panel having a good surface condition is used, and a method for producing the same. 9. A die-cast door panel manufactured by the method according to claim 1, having a thickness of 1.5 to 3 mm. 10. A door panel made of die-cast, wherein the panel according to claim 9 is further heat-treated to have an elongation of 3% or more.