JP4421964B2 - Casting mold - Google Patents

Description

  The present invention relates to a casting mold configured to include a pair of molds such as a fixed mold and a movable mold, and a mold such as a cavity mold fitted between both molds. The present invention relates to a casting mold including a sealing member that hermetically seals between constituent molds.

  There are a wide variety of casting methods using a mold instead of a sand mold, including a high pressure die casting method, a low pressure die casting method, a squeeze method, and a vacuum casting method. A common requirement for a casting apparatus that decompresses the inside of a mold is to ensure high airtightness inside the apparatus when the mold is clamped.

  In general, in casting, gas such as hydrogen dissolved in molten metal (molten metal) and atmospheric gas present in the mold become bubbles during casting, which inhibits molding and forms a nest inside the casting. Reducing mechanical properties. Therefore, it is effective to remove various gases by reducing the pressure in the mold. For this purpose, it is important to evacuate the mold with high airtightness. As described above, when any casting method is adopted, it is common in that a cast product can be mass-produced with high accuracy by ensuring high airtightness.

  By the way, as a means for ensuring airtightness such as an oil seal, it is general to use a seal member typified by an O-ring. For example, Patent Document 1 relating to a low-pressure casting apparatus includes a fixed mold (base plate 3) and a movable mold (lower mold 2), and an upper and lower molds (upper mold 1 and lower mold 2) in FIG. A sealing member 13 such as an O-ring is interposed to ensure airtightness between the molds.

  Further, Patent Document 2 relating to a vacuum casting apparatus is shown in FIG. 13a is installed.

Further, FIG. 1 of Patent Document 3 relating to the die casting apparatus shows a seal member 17 that seals the joint surface 13 between the fixed mold 10 and the movable mold 11.
Japanese Utility Model Publication No. 5-39737 (FIG. 1) Japanese Patent Laid-Open No. 7-32125 (FIG. 1) Japanese Patent Laying-Open No. 2003-191059 (FIG. 1)

  It is known that the airtightness obtained by the O-ring described above depends on the shape of the seal groove that accommodates the O-ring.

  For example, the seal groove shown in FIG. 1A is referred to as a “square groove”. In this case, when the O-ring 1 is installed on the joint surface 4 between the upper mold 2 and the lower mold 3, and when the joint surface 4 presses the O-ring 1 in the vertical direction on the paper surface, the most airtightness is obtained. It will be. However, since there is almost no regulating means for the O-ring 1 when accommodated in the square groove, the holding ability for the O-ring 1 is lacking.

  Moreover, the seal groove of FIG. 1B is called “the dovetail groove”, and compensates for the disadvantage that the holding ability for the O-ring 1 cannot be obtained with the square groove shape shown in FIG. . That is, the openings 6a and 6b of the recess 5 that accommodates the O-ring 1 are reduced in diameter from the bottom surface 7 so that the O-ring 1 is fitted in the seal groove.

  Further, the seal groove in FIG. 1C is called a “triangular groove”, and the corner portion 9 of the upper mold 8 is chamfered to form a slope 10. By this chamfering, a gap 12 (“triangular groove”) having a triangular cross section is formed between the upper mold 8 and the lower mold 11 when the mold is clamped, and the O-ring 1 is accommodated in the gap 12. When this triangular groove is used, clamping by the upper and lower molds 8 and 11 is performed in the vertical direction on the paper surface, while the press contact with the O-ring 1 is performed in the normal direction of the inclined surface 10. Therefore, there is a problem in that the two deviate at an angle of approximately 45 °, and the airtightness cannot be obtained with the maximum efficiency. Further, due to this angular divergence, an equal pressure on the O-ring 1 cannot be obtained, and the position of the O-ring 1 tends to shift. For this reason, the holding ability with respect to the O-ring 1 is limited, and the function is limited to simple fixing of both molds 8 and 11 rather than the purpose of securing the original airtightness.

  By the way, manufacturing with a casting mold including a pair of molds such as a movable mold and a stationary mold and a cavity mold for transferring a product shape is generally performed by the following procedure.

  1) A cavity mold having a nested structure in which a product shape is engraved is fitted into a mold body that functions as an outer frame.

  2) The mold body integrated with the cavity mold is used as a movable mold or a fixed mold, and the cavity mold is fitted between both molds by matching each other.

  3) Clamping is performed between the movable mold and the fixed mold.

  4) The molten metal is poured into the mold that has been clamped to obtain a cast product.

  As described above, in order to mass-produce cast products with high precision in such a casting mold, the sealing member such as an O-ring is important. As shown in FIG. This seal groove has advantages and disadvantages in securing the airtightness of the casting mold, and is not ideal.

  For example, FIG. 2A shows the relative positions of the mold body 21 in which the square groove 20 is installed and the cavity mold 22 fitted in the mold body 21. When the cavity mold 22 is fitted to the mold main body 21, the cavity 22 is slid in the vertical direction. At this time, the O-ring 1 installed in the square groove 20 is moved by the bonding surface 22 a of the cavity 22. Shear stress acts and the O-ring 1 is easily broken.

  FIG. 2 (b) shows the O-ring 1 held by a “groove” 23 a provided in the mold body 21 and a “groove” 23 b provided in the cavity mold 22. However, when the mold body 21 and the cavity mold 22 are made of different materials, the vertical position is shifted between both the “grooves” 23a and the “grooves” 23b due to the difference in coefficient of thermal expansion between each other. Therefore, it becomes difficult to securely hold the O-ring 1.

  Further, FIG. 2 (c) shows a “triangular groove” 25 using a space having a triangular cross section obtained by chamfering the corner 24 of the mold body 21. When the cavity mold 22 is fitted to the mold body 21 having the triangular groove 25, there is nothing to restrict the upper part of the O-ring 1, so that the O-ring 1 cannot be held. Then, when the mold body 21 and the cavity mold 22 are opened, problems such as the O-ring 1 dropping off occur.

  As described above, even when any seal groove is used, the reliability is low in terms of the holding ability with respect to the O-ring 1, and it is difficult to obtain reliable airtightness.

  In view of the above problems, an object of the present invention is to provide a casting mold that can ensure airtightness by a sealing member that is securely held at a joint surface between the molds.

In order to solve the above problems, a casting mold of the present invention includes at least three molds including a pair of molds and a cavity mold fitted between the pair of molds. The cavity mold is fitted to at least one of the molds, and both the one mold and the cavity mold are integrated, and then the mold is clamped by the one mold and the other mold, A casting mold having a sealing member that hermetically seals between three molds, and chamfers at a corner of the one mold that faces the other mold and faces the cavity mold when the mold is clamped Or when the mold is clamped, the corner of the cavity mold facing the other mold and facing the one mold is chamfered, and the inclined surface dropped by the chamfering and both ends of the inclined surface Provided at one end of the other mold side The raised portion is connected in a curled shape to form a seal groove for the seal member, and when the seal member is installed in the seal groove, the seal member is held by the protruding portion. Features.

According to this, since the protruding portion provided at one end of the triangular groove functions as a hook mechanism of the sealing member, the holding ability of the sealing member which is insufficient in the case of a simple triangular groove is improved, and the mold is clamped Airtightness can be reliably obtained.

  The casting mold of the present invention includes a sealing groove having a shape in which a triangular groove portion and a protruding portion provided at one end portion on the other mold side of both ends of the triangular groove portion are connected. The holding capacity for the member is enhanced. Therefore, by the sealing member installed in the sealing groove, reliable airtightness can be obtained at the joint surface between the molds, and the yield reduction in the manufacturing process of the cast product can be prevented.

  Further, since the seal groove provided in the casting mold of the present invention is provided at a position that simultaneously faces at least three molds including a pair of molds to be clamped and a cavity mold, contact surfaces of all the molds Assured airtightness can be secured. For this reason, the effect that the number of required sealing members can be reduced is also obtained.

  FIG. 3 shows a part of the process using the casting mold of the present invention. Before the mold is aligned with the fixed mold outside the figure, the product shape is shown with respect to the mold body 31 functioning as the outer frame. The state immediately before fitting the cavity mold 32 having the nested structure is shown. The corner portion 33 of the mold body 31 is chamfered to form a triangular groove portion 34 composed of a slope 34 dropped by this chamfering. A portion 36 is formed. A curl-shaped portion 34-36 in which the triangular groove portion 34 and the protruding portion 36 are connected is used as a seal groove. When the seal groove having such a shape is used, the O-ring 1 is hooked by the protruding portion 36 when the O-ring 1 is installed in the seal groove 34-36. Therefore, when the cavity mold 32 is fitted to the mold body 31, it is possible to avoid the situation where the O-ring 1 is displaced upward, and the O-ring seen when a seal groove having a triangular groove shape is used. 1 can be prevented from falling off.

  FIG. 4 shows a state in which the mold body 31 provided with the sealing grooves 34 to 36 is used, and the cavity mold 32 and the mold body 31 are integrated and fixed to the fixed mold 41 according to a general casting process. Show. At this time, the cavity mold 32 is fitted into the mold body 31. Thereafter, the mold body 31 and the fixed mold 41, which are movable molds, are clamped, and a high temperature molten metal is poured into the clamped casting mold to obtain a cast product.

  As shown in FIG. 4, when the mold body 31 and the cavity mold 32 come into contact with each other, a stress in the upward direction on the paper surface acts on the O-ring 1 accommodated in the seal grooves 34-36. However, the O-ring 1 is locked to the protrusion 36, and further, press contact from the fixed mold 41 is applied, so that the O-ring 1 is securely held in the seal groove 34-36. And thereby, high airtightness is ensured and it becomes possible to manufacture a cast product with high quality with high accuracy.

  In this embodiment, the curl-shaped seal grooves 34-36 are provided in the mold body 31, but as is apparent from the arrangement of FIG. 3, the same effect can be obtained even if provided at the corners of the cavity mold 32. it is obvious. In this embodiment, the cavity mold 32 and the curl-shaped sealing grooves 34-36 are provided in the mold body (movable mold) 31, but as is apparent from the arrangement of FIG. It is apparent that the same effect can be obtained by providing both the mold body (movable mold) 31 and the fixed mold 41 simultaneously.

  Further, since the seal grooves 34 to 36 are provided so as to simultaneously contact the mold body 31 and the fixed mold 41 that perform mold clamping, and the three molds of the cavity mold, the seal grooves 34 to 36 are formed on the contact surfaces of all molds. Secure airtightness. Since the seal groove 34-36 is used in this way, it is located at a portion where the component mold can be efficiently contacted, so that the number of O-ring parts required in the casting mold apparatus can be reduced and the mold can be used. The number of man-hours for mold production can be reduced.

  The seal groove provided in the casting mold of the present invention can be used not only for the casting mold application but also for a vacuum processing apparatus that needs to ensure airtightness, for example, a vacuum film forming apparatus.

(A) Schematic cross section showing a square groove (b) Schematic cross section showing a “groove” (c) Schematic cross section showing a triangular groove (A) Schematic cross-sectional view when a square groove is applied to the casting mold (b) Schematic cross-sectional view when the “groove” is applied to the casting mold (c) When a triangular groove is applied to the casting mold Cross-sectional schematic diagram Schematic diagram showing just before the cavity mold is fitted to the movable mold provided with the seal groove A schematic diagram showing a state in which a seal member is housed in a seal groove provided in a movable mold and the fixed mold and the movable mold are clamped.

Explanation of symbols

1 O-ring (seal member)
31 type body (movable type)
32 Cavity mold 41 Fixed mold 33 Corner 34 Slope 36 Projection

Claims (1)

At least three molds including a pair of molds and a cavity mold fitted between the pair of molds, and the cavity mold is fitted to at least one of the pair of molds. Then, after both the one mold and the cavity mold are integrated, the mold is clamped by the one mold and the other mold, and the casting is provided with a seal member that hermetically seals between the three molds. Mold,
When the mold is clamped, the corner of the one mold facing the other mold and facing the cavity mold is chamfered, or when the mold is clamped, the other mold is opposed to the one mold. Chamfer the corner of the cavity mold facing the mold,
Connecting the inclined surface dropped by the chamfering and a protruding portion provided at one end portion on the other mold side of both ends of the inclined surface to form a seal groove for the seal member;
When the seal member is installed in the seal groove, the seal member is held by the protruding portion.
A casting mold characterized by that.

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