JP3037920B2 - Method of insert molding V lip packing around the circumference of a disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for providing a V lip packing on the outer periphery of a circular plate by insert molding, for example, providing a V lip packing on a heat radiating plate on a lower surface of a lid of a rice cooker.

[0002]

2. Description of the Related Art As shown in FIG. 1, a lid (12) of a rice cooker (1).
A radiator plate (2a) is attached to the lower surface, and a V lip is formed on the outer lower surface of the radiator plate (2a) to abut on the inverted conical surface (14) of the opening edge of the rice cooker body (11) to form a seal. A packing (3) is provided with the opening of the groove (33) facing inward.

[0003] The V lip packing (3) is a rice cooker (1).
The inner vapor pressure acts in the direction of expanding the groove (33) of the V lip packing (3), and the outer lip piece (32) of the V lip packing (3)
Is pressed against the conical surface (14) of the main body (11) to prevent vapor from escaping from between the main body (11) and the lid (12). Therefore, the inner lip piece (31) of the V lip packing (3)
The angle between the outer lip piece (32) and the outer lip piece (32) is important.
4) A gap is created between them and steam escapes.

Conventionally, a V lip packing is attached to the outer periphery of the heat sink (2a) by mechanical coupling. For this reason, a groove for mounting the V lip packing on the outer periphery of the heat sink (2a),
A tightening ring is required, and the number of parts increases. Also, V
It takes time to attach the lip packing, resulting in high cost. Furthermore, if scale or foreign matter accumulates in the minute gaps in the V-lip packing assembly part, it cannot be completely removed even by washing, and there is a problem that various bacteria easily propagate and become unsanitary.

[0005] Therefore, as shown in FIG.
An attempt was made to insert-mold a V lip packing (3) having an opening angle indicated by a two-dot chain line on the outer periphery of (2a). Heat sink (2a)
Directly fixing the leading edge of the inner lip piece (32) of the V lip packing (3) on the
Reliable bonding cannot be expected. For this reason, an annular covering portion (30) that covers the outer peripheral portion of the heat sink (2a) in a tightly fixed state, and a V-lip in which the entire periphery of the leading edge of the inner lip piece (31) is integrally connected to the covering portion (30). An attempt was made to insert-mold the packing (3) on the heat sink (2a) at the same time.

In view of the thermal deformation of the molding material, the diameter of the cavity corresponding to the V lip packing of the annular cavity is indicated by a dashed line, so that the entire V lip packing is completed.
When it was designed and molded slightly larger than (3), the angle formed by the two lip pieces (31a) and (32a) forming the V-shape of the V lip packing (3a) became smaller, as indicated by hatching. The desired shape shown by the chain line was not finished.

This is because, of the two lip pieces (31a) and (32a) of the V lip packing (3a), the leading edge of the inner lip piece (31a) on the heat radiating plate (2a) side is a heat radiating plate. (2a) Shrinkage is prevented by being integrally connected to the covering portion (30) which is tightly adhered on the upper portion, and the inner lip piece (31a) has a diameter from the leading edge toward the V-shaped proximal edge. Because of the expansion, the shrinkage is hindered, so that the amount of shrinkage of the inner lip piece (31a) is extremely small, and the angle of the inner lip piece (31a) hardly changes. On the other hand, V
The outer lip piece (32a) of the lip packing (3), which is farther from the heat sink (2a), has a reduced diameter from the V-shaped base end to the tip and is also unconstrained, so that the amount of shrinkage is large. Outer lip piece (32
The diameter of the leading edge of a) is greatly reduced, and consequently the outer lip piece
(31a) falls down to the inner lip piece (31a) side, and both lip pieces (31a) (32
The angle formed by a) becomes smaller.

The present invention fully considers the above phenomenon and clarifies a method of forming a V-lip packing having a predetermined opening angle on an annular covering portion which closely covers the outer periphery of a heat sink in a fixed state by insert molding. It is to be. In addition, the present invention is not limited to the heat radiating plate of the rice cooker, but can be of course applied to a member that needs to form the V lip packing on the outer peripheral portion of the disk.

[0009]

According to the present invention, there are provided an annular covering portion (30) which is in close contact with the outer periphery of a disk, a V-shaped cross section, and an opening of a groove (33) facing inward. 31) A method of insert-molding a V-lip packing (3) in which an inner lip piece (31) is integrally connected to the coating portion (30) on a disk, wherein a mold cavity (31) is provided. 5) is a space (50) corresponding to the annular covering portion (30) and a cross section V corresponding to the V lip packing (3).
The space (53) is connected to the V-shaped space.
Of (53), the space (52) corresponding to the outer lip piece (32) on the side of the V lip packing (3) away from the disk corresponds to the inner lip piece (31) of the V lip packing (3). Space part to do (51)
In contrast, the mold lip is opened outward in accordance with the heat shrinkage of the molding material, and the V lip packing is opened in accordance with the heat shrinkage of the molding material by opening the mold after injecting the molding material into the cavity (5).
A circle characterized in that the inside diameter of the opening edge on the side remote from the disk of (3) is shrunk, and a V-lip packing (3) having a predetermined opening angle is formed on the annular covering portion (30) on the outer periphery of the disk. V-lip packing is insert-molded on the outer periphery of the plate.

Specifically, the disk is a heat radiating plate (2a) of the lid (12) of the rice cooker, and the covering portion (30) and the V lip packing (3).
Is a silicone rubber.

More specifically, an adhesive may be applied to the outer peripheral portion (21) of the disk before the molding material is injected.

[0012]

[Function and effect] Since the V lip packing (3) is insert-molded on the outer periphery of the disk, processing for assembling the V lip packing (3) to the disk as in the related art, and the labor for assembling are unnecessary. The score can be reduced. Since there is no room for scale or foreign matter to enter between the disk and the V lip packing (3), dirt can be easily removed and hygiene is excellent.

The V-lip packing (3) is formed integrally with the coating (30) on the annular coating (30), which is closely covered over a wide area of the outer periphery of the disk. ) May not come off.

As described above, after opening the mold, the V lip packing
Although the angle of the inner lip piece (31) in (3) hardly changes, the outer lip piece (32) contracts at the leading edge side, narrows the opening edge, and consequently approaches the inner lip piece (31) side. In the present invention, the space portion (52) corresponding to the outer lip piece (32) of the cavity (5) is
The angle formed by both space portions with respect to the space portion (51) corresponding to the inner lip piece (31) is larger than the angle formed by both lip pieces (31) and (32) of the completed V lip packing (3). Since the amount of thermal deformation of the material was increased in consideration of the material, the outer lip piece (32) after opening the mold
The angle formed by the inner lip pieces (31) and (32) of the V lip packing (3) becomes a predetermined angle only when the inner lip piece approaches the inner lip piece (31).

[0015] Silicone rubber is excellent in heat resistance and water resistance, and is most suitable for use in a steam seal of a rice cooker.
By applying an adhesive having excellent adhesiveness to the disk and the molding material on the outer periphery of the disk prior to insert molding, the disk and the covering portion (30) can be prevented from peeling off.

[0016]

FIG. 2 shows a mold (4) in which a V lip packing (3) is insert-molded on the outer periphery of a circular heat sink (2a) of a rice cooker (1), and FIG. It is a principal part enlarged view of a mold cavity (5). FIG. 4 is an enlarged sectional view of a main part in which a V-lip packing (3) is formed in a ring shape by insert molding on the outer periphery of the heat sink (2a).

As shown in FIGS. 2 and 4, V lip packing
(3) is insert-molded upside down from the use state of the lid (12) shown in FIG. The circular radiator plate (2a) is formed of aluminum. The V lip packing (3) is formed of a silicone resin.

As shown in FIGS. 2 and 4, the heat radiating plate (2a) folds the outer periphery of the disk body downward and inward, raises it at a right angle, and raises the short cylindrical portion (22) into the lid (12). ) Is formed.

The V lip packing (3) has the opening of the groove (33) facing inward and has an outer diameter of about 240 mm. Of the two lip pieces (31) and (32) of the V lip packing (3), the leading edge of the inner lip piece (31) on the heat sink (2a) side is an annular covering part (30) over the entire circumference.
Are connected to one another. The covering portion (30) covers the upper surface of the outer peripheral portion (21) of the heat sink (2a) in a tightly fixed state.

The angle formed by the inner lip piece (31) and the outer lip piece (32) shown by the solid line in FIG. 4 is equal to the groove (33) of the V lip packing (3).
A plane F passing through the center of the width and parallel to the center flat surface of the heat sink (2a)
About 28 ° respectively. Each of the inner lip piece (31) and the outer lip piece (32) has a thickness of about 1 mm, and has the flexibility of being freely elastically deformed by lightly pressing.

The portion shown by the two-dot chain line in FIG. 4 is the appearance of the V lip packing (3) in the mold in consideration of the thermal deformation of the silicone rubber which is the molding material of the V lip packing (3).
Inner lip piece (31) on heat sink (2a) side of V lip packing (3)
Is slightly rising after the mold is opened, and the outer diameter is slightly reduced but negligible. This is because the leading edge of the inner lip piece (31a) on the side of the radiator plate (2a) is the radiator plate (2a) of the two lip pieces (31) and (32) of the V lip packing (3).
The shrinkage is prevented by being integrally connected to the covering portion (30) overlaid thereon, and the inner lip piece (31) is prevented from shrinking because the diameter increases from the distal edge toward the V-shaped proximal edge. This is because the amount of shrinkage is extremely small.

On the other hand, the heat radiating plate (2a) of the V lip packing (3)
The outer lip piece (32) farther from the inner lip piece is inclined toward the inner lip piece (31) by about 30 ° from the V-shaped base end. This is because the outer lip piece (32) is reduced in diameter toward the tip, and is not restrained when the mold is opened, and the amount of shrinkage is large. When the outer lip piece 32 falls inward, the groove 33 becomes a predetermined angle (about 56 ° in the embodiment), and the diameter of the leading edge of the outer lip piece 32 is reduced.
In the embodiment, the inner diameter of the outer edge of the outer lip piece (32) is reduced to about 223 mm after about 230 mm in the mold is opened.

The insert molding die (4) shown in FIG.
The lower mold (41) with the lower core (44), the upper mold (43) with the upper core (45), and the lower mold (41) surrounding the cores (44) and (45) Type
(43). The radiator plate (2a) is set between the lower core (44) and the upper core (45), and is connected to the lower core (44), the lower die (41), the upper core (45), and the intermediate die (42). Between the covering part (30) and V lip packing
An annular cavity (5) corresponding to (3) is formed.

A plurality of gates (46) are formed between the upper mold (43) and the intermediate mold (42) to feed the molding material into the cavity (5). In the above cavity (5), V lip packing
The V-shaped space (53) composed of the space portions (51) and (52) corresponding to the inner lip piece (31) and the outer lip piece (32) of (3) is a V lip shown by a two-dot chain line in FIG. Needless to say, it corresponds to the shape of the packing.

The molding material heated and melted is injected into the cavity (5) of the mold (4) in which the heat radiating plate (2a) is set, and after the molding material is solidified, the mold is opened and a V lip packing (3) is provided. Take out the heat sink (2a).

As described above, in order to insert-mold the V lip packing (3) on the outer periphery of the heat radiating plate (2a), processing for incorporating the V lip packing (3) into the heat radiating plate (2a) as in the related art is performed.
There is no need for assembling. In addition, since there is no room for scale or foreign matter to enter between the heat radiating plate (2a) and the V lip packing (3), dirt can be easily removed and hygiene is excellent.

As described above, after opening the mold, the V lip packing
Although the angle of the inner lip piece (31) in (3) hardly changes, the outer lip piece (32) contracts at the leading edge side, narrows the opening edge, and consequently approaches the inner lip piece (31) side. In the present invention, the space portion (52) corresponding to the outer lip piece (32) of the cavity (5) is
The angle formed by both space portions with respect to the space portion (51) corresponding to the inner lip piece (31) is larger than the angle formed by both lip pieces (31) and (32) of the completed V lip packing (3). After opening the mold, the outer lip piece (32)
V lip packing for the first time after approaching 1)
The angle formed by the inner lip pieces (31) and (32) of (3) is a predetermined angle.

A V-lip packing (3) is formed integrally with the covering (30) on the annular covering (30) which covers the heat-dissipating plate (2a) closely over a wide area of the outer periphery. Packing
There is no fear that (3) will come off.

Prior to the insert molding of the V lip packing (3), the V lip packing (3) including the disk and the coating (30) is formed on the outer peripheral portion (21) of the disk set in the mold. If the adhesive (23) having good adhesiveness to the material is applied, the bonding between the disc and the cover (30) is further strengthened.

It should be noted that the present invention is not limited to a radiator plate of a rice cooker,
Of course, the present invention can be applied to a member that needs to form the V lip packing on the outer peripheral portion of the disk. Also, V lip packing
The molding material for (3) and the covering portion (30) is not limited to silicone rubber, and an optimum insert molding material may be selected according to the application.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cross section of a part of a heat sink in a state where a lid of a rice cooker is closed.

FIG. 2 is a sectional view of an insert molding die.

FIG. 3 is a sectional view of a main part of a mold.

FIG. 4 is a cross-sectional view showing a deformed state of the V lip packing after the mold is opened.

FIG. 5 is a cross-sectional view showing a V-lip packing deformation state by insert molding performed by the applicant prior to the present invention.

[Explanation of symbols]

 (1) Rice cooker (12) Lid (2) Disk (2a) Heat sink (21) Perimeter (23) Adhesive (3) V lip packing (30) Cover (31) Inner lip (32) Outer lip piece

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-192611 (JP, A) JP-A-5-8248 (JP, A) JP-A-9-152039 (JP, A) JP-A-4- 33817 (JP, A) JP-A-3-187718 (JP, A) JP-A-62-251115 (JP, A) JP-A-1-104310 (JP, U) JP-A-7-714 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (3)

(57) [Claims] An annular covering portion (3) which is tightly covered on the outer periphery of a disk.
0), the inner lip piece (31) of the two inner and outer lip pieces (31) and (32) is formed integrally with the coating portion (30) with the opening of the groove (33) facing inward with a V-shaped cross section. A method of insert-molding a V lip packing (3) connected to the above on a disk, wherein a mold cavity (5) is provided with a space (50) corresponding to the annular coating portion (30) and a V lip packing (3). 3) and a corresponding space 53 having a V-shaped cross-section (53) are connected to each other. Of the space 53 having the V-shaped cross-section, an outer lip piece ( The space (52) corresponding to (32) is opened outward with respect to the space (51) corresponding to the inner lip piece (31) of the V lip packing (3) according to the heat shrinkage of the molding material. The cavity
By opening the mold after injecting the molding material into (5), the inner diameter of the opening edge of the V lip packing (3) on the side remote from the disk is shrunk in accordance with the amount of heat shrinkage of the molding material, and the annular shape of the outer periphery of the disk Coating
(30) A method of insert-molding a V-lip packing on the outer periphery of a disk, wherein a V-lip packing (3) having a predetermined opening angle is formed thereon. 2. The molding material of the V lip packing (3) and the covering portion (30) is silicone rubber, and the disk is a lid of a rice cooker.
2. The method according to claim 1, wherein the heat radiating plate (2a) is insert-molded with a V-lip packing on the outer periphery of the disk. 3. An outer peripheral portion (21) of the disk is coated with an adhesive having good adhesiveness with the disk and the covering portion (30) before the molding material is injected. Or a method of insert-molding a V-lip packing around the outer periphery of the disk according to any one of the above items.