JPS644860B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention is a method for casting a trim lower mold for trimming the outer panel of an automobile body by a full mold method. The present invention relates to a mold model made of styrofoam.

(2) Prior Art Conventionally, it has been common practice to integrally mold the molding model of the trim lower mold, which has a complicated shape, using expanded polystyrene.

(3) Problems to be solved by the invention By the way, when designing the above mold model,
After the shape of the molding surface has been determined, we consider the placement of reinforcing ribs, etc., and complete the design drawings, so we have to wait until the design drawings are completed before molding the mold model, and the drawings are complicated and difficult to read. It was hot. Furthermore, even if the design of only the molding surface of the model is changed due to a change in the shape of the workpiece (vehicle body exterior), the entire design of the model must be redone and all the molds must be replaced, increasing costs. There's a problem.

The present invention has been made in view of the above circumstances, and provides a trim for trimming an outer panel of a vehicle body, which improves the efficiency of processing work and reduces costs by joining a plurality of members to form a mold model. The purpose is to provide a mold model of the lower mold.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a method for casting a trim lower mold for trimming the outer panel of an automobile body by a full molding method. In a mold model made of styrofoam, a base forming member having a shape corresponding to the base portion of the lower trim mold, and a support frame portion having legs reinforcing sides of the base are formed on the lower trim mold. A support frame forming member for forming the base member and a molding surface forming member having a shape corresponding to the molding portion supported by the support frame portion are joined to each other, and the base forming member has an upper surface formed in a chevron-shaped cross section. The support frame forming member has a bifurcated support leg that straddles the upper surface of the main body and contacts both side surfaces of the main body.

(2) Effects When designing and processing a mold model, the base forming member is designed generally in accordance with the size and car model of the workpiece to be machined, and the molding surface is formed in accordance with the shape of the workpiece. After designing the members and further designing the support frame forming member to specifically align the molding surface forming member with the base forming member, processing each forming member independently, and then joining them together. You can easily process and assemble a trim lower mold mold model with a complex shape just by using
The design drawings of each forming member are significantly simplified, making them easier to see during machining, and the need for machining of parts with complex shapes is reduced, which can greatly contribute to improving machining efficiency.

Further, the closed cross-sectional structure of the body of the base forming member makes it possible to reduce the weight while maintaining the rigidity of the base forming member itself and the base of the lower mold. The upper surface serves as a guide surface when the bifurcated support legs of the support frame forming member are straddled thereon, and the bifurcated support legs can be easily and accurately placed on the upper surface. The lateral movement of the support frame forming member is restricted by the contact between the bifurcated support legs, and this makes it extremely easy to position and maintain the support frame forming member relative to the base forming member. Furthermore, since the upper surface of the base forming member having a chevron-shaped cross section can correspondingly form a pair of outwardly downward inclined surfaces on the upper surface of the base of the lower trim mold, both of these inclined surfaces can be used as a scrap chute. can do.

(3) Embodiment Below, an embodiment of the present invention will be explained with reference to the drawings. First, in FIG. 1, which shows an embodiment of the present invention, this mold 1 is used to trim the outer panel of an automobile body. This is a lower mold, and includes a base 2, a support frame 3, and a molding part 4 that are integrally formed.

In FIG. 2, the base 2 is formed to have a hollow closed cross-sectional shape. For example, the cross-sectional shape perpendicular to the longitudinal direction of the base 2 includes a bottom plate part 5, a pair of side plate parts 6 facing each other and standing upright on the bottom plate part 5,
6, and a pair of upper plate parts 7, 7 which are provided so as to be inclined toward each other as they move upward from the upper ends of the side plate parts 6, 6, and are connected to each other at the upper ends. Further, collar portions 8, 8 that protrude outward from the side plate portions 6, 6 are provided so as to be continuous with both side ends of the bottom plate portion 5. Since the upper surface of the base portion 2 has a chevron-shaped cross section, the pair of inclined surfaces thereof can function as a scrap chute for guiding the scrap generated during trimming to the outside.

In FIG. 3, the bottom plate portion 5 has a plurality of through holes 9.
is drilled. These through holes 9 are formed into rhombic and triangular shapes. As a result, the through holes 9 form a beam shape that intersects with each other in an X shape.

Guide blocks 10 are integrally provided at both longitudinal ends of the base 2, and each guide block 10 is provided with a pair of guide post holes 11, respectively.

The support frame portion 3 is constructed by connecting the upper ends of a plurality of leg portions 12, for example, three, with a support plate portion 13 having a shape corresponding to the molded portion 4. Each leg 12 is arranged in a plane perpendicular to the longitudinal direction of the base 2 at positions spaced apart from each other in the longitudinal direction of the base 2. , 8.

The molded portion 4 is formed to have a shape corresponding to the outer panel of an automobile body, and has an outer edge portion and
A blade portion 15 is attached to the periphery of the opening portion 14 corresponding to the door.
are provided respectively.

Such a trim lower mold 1 is cast by a full mold method, and a mold model 16 for casting the lower mold 1 includes a base forming member 17 and a base forming member 17, as shown in FIG. , support frame forming member 18
and the molding surface forming member 19 are bonded to each other with an adhesive, and each forming member 17, 18, 1
9 is made of styrofoam.

The base forming member 17 is connected to the guide blocks 10,1
0, the support frame forming member 18 has a shape corresponding to the support frame part 3, and the molding surface forming member 19 has a shape corresponding to the molding part 4. . The base forming member 17 has a main body 17a having a hollow closed cross-sectional structure corresponding to the base 2 of the lower mold 1.
The upper surface of the base 2 is also formed to have a chevron-shaped cross section, similar to the upper surface of the base 2. Further, the support frame forming member 18 includes the main body 17
It has a bifurcated support leg 18a that straddles the upper surface of the main body 17a and contacts both side surfaces of the main body 17a. becomes the guide surface.

The lower trim mold 1 having a shape corresponding to the mold model 16 is obtained by burying such a mold model 16 in heat-resistant sand, injecting molten metal, and burning and removing the mold model 16.

Next, to explain the operation of this embodiment, the lower mold 1 performs trim processing in cooperation with the corresponding upper mold (not shown), and at that time, the pressing force acting on the molding part 4 is as follows. It acts on the base 2 via the support frame 3. However, the upper plate parts 7, 7 of the base 2 are inclined downward on both sides, and some of the pressing force is borne by the legs 12, 12 of the support frame part 3. Therefore, the load borne by the base 2 is relatively small, and it is not necessary to provide a large number of reinforcing beams within the base 2. In addition, a load is applied to the molded part 4 to push it apart during press working, and a tensile force is applied to the bottom of the base 2, but because the bottom is in the shape of an X beam, the It can effectively withstand tensile force, and can prevent bending deformation due to unbalanced pressing force during press working.

In such a lower mold 1, the inside of the base 2 is hollow, and the support frame part 3 is also formed in the form of a framework, so that the overall weight can be reduced and a sufficient weight reduction can be achieved.

By the way, when designing and processing the mold model 16, first, the base forming member 17 is designed in accordance with the size of the work to be processed (vehicle body outer plate) and the type of vehicle, and then the The molding surface forming member 19 is designed specifically corresponding to the shape of the workpiece,
Furthermore, the molding surface forming member 19 is attached to the base forming member 1.
The support frame forming member 18 can be designed to match the shape of the support frame forming member 18, and each forming member 17, 18, 19 can be processed and formed independently.This makes it extremely easy to see the design drawing during processing, and it is also possible to avoid parts with complex shapes. With less machining, the machining time can also be shortened. Furthermore, even if the shape of the molding surface forming member 19 is slightly changed, the design drawings of the base forming member 17 and the support frame forming member 18 can be used as they are.

The closed cross-sectional shape of the base 2 may be as shown in FIGS. 5 and 6, and the bottom of the base 2, that is, the bottom plate 5, may have a rectangular through hole 9' as shown in FIG. A plurality of beams may be provided so that the bottom of the base 2 forms a cross-shaped beam.

C. Effects of the Invention As described above, according to the present invention, in a mold model formed of polystyrene foam for casting a trim lower mold for trimming the outer panel of an automobile body by a full molding method, the trim lower mold A base forming member having a shape corresponding to a portion that will become the base of the mold; a support frame forming member for forming a support frame portion having legs reinforcing the side portions of the base on the trim lower mold; and a support frame portion. Since the molding surface forming members with shapes corresponding to the molding parts supported by the molding parts are joined to each other, the design and processing of the mold model generally depends on the size and car model of the workpiece (external body panel) to be processed. The base forming member is designed accordingly, the molding surface forming member is designed specifically corresponding to the shape of the work, and the support frame forming member is designed to specifically match the molding surface forming member to the base forming member. A mold model for a trim bottom mold with a complex shape can be easily processed and assembled simply by designing each forming member, processing each forming member independently, and then joining them together. The design drawings of the forming parts are significantly simplified, making them easier to see during machining, and there is less machining of parts with complex shapes, which greatly contributes to improving machining efficiency. Regarding the base forming member, even if the shape of the upper molding surface forming member is slightly changed, it can be processed to the previous form without changing the design, which can contribute to cost reduction. Furthermore, since strict precision control during processing only needs to be performed on the molding surface forming member of the lower model, this can contribute to reducing processing costs.

Further, the base forming member has a main body having a hollow closed cross-sectional structure with an upper surface formed in a chevron-shaped cross section, and the support frame forming member has a bifurcated support that straddles the upper surface of the main body and contacts both side surfaces of the main body. Because it has legs,
Due to the closed cross-sectional structure of the body of the base forming member, it is possible to reduce the weight while maintaining the rigidity of the base forming member itself and the base of the lower mold. When the bifurcated support legs of the support frame forming member are straddled there, the bifurcated support legs can be placed easily and accurately, so that the bifurcated support legs can be placed on both sides of the main body. The lateral movement of the support frame forming member is restricted by the contact of the support legs, and this makes it extremely easy to position and maintain the support frame forming member relative to the base forming member, and the joining work between the two members is extremely easy. This can contribute to improving efficiency. Moreover, since the upper surface of the base forming member having a chevron-shaped cross section can correspondingly form a pair of outwardly downward inclined surfaces on the upper surface of the base of the lower trim mold, these two inclined surfaces can be formed during trimming. It is convenient because it can be used as a scrap chute to guide the scrap outward.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is a perspective view of a mold, Figure 2 is a sectional view taken along the line - - in Figure 1, and Figure 3 is a cross-sectional view of Figure 2. - line sectional view, Figure 4 is an exploded perspective view of the mold model, and Figures 5 to 7 show modified examples of the base.
6 and 6 are cross-sectional views corresponding to FIG. 2, and FIG. 7 is a cross-sectional view corresponding to FIG. 3. 1...Lower mold, 2...Base, 3...Support frame part, 4
. . . Molding section, 16 . . . Mold model, 17 .

Claims (1)

[Claims] 1. In a mold model made of polystyrene foam for casting a trim lower mold 1 for trimming the outer panel of an automobile body by a full mold method,
For forming a base forming member 17 having a shape corresponding to the portion that will become the base 2 of the trim lower mold 1, and a support frame portion 3 having leg portions for reinforcing the side portions of the base 2, on the trim lower mold 1. A support frame forming member 18 and a molding surface forming member 19 having a shape corresponding to the molding part 4 supported by the support frame part 3 are joined to each other,
The base forming member 17 has a main body 17a having a hollow closed cross-sectional structure with a chevron-shaped upper surface, and the support frame forming member 18 straddles the upper surface of the main body 17a and extends on both sides of the main body 17a. A molding model of a lower trim mold for trimming an outer panel of a vehicle body, characterized by having bifurcated support legs 18a that are in contact with each other.