JP2003103560A - Insert molding method and insert molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an insert molded article excellent in part accuracy and having an insert article accurately arranged thereto without increasing part manufacturing cost or mold manufacturing cost. SOLUTION: In the insert molding method for molding the insert molded article 10 having a plurality of insert articles 11, 12 and 13 inserted therein in a mutually contact state so that the peripheries of the mutually joined parts of the insert articles 11, 12 and 13 are covered with a molten resin, a fixing process for filling a cavity 20C, in which a plurality of the insert articles 11, 12 and 13 are held at predetermined positions in an integrally grasped state, with the molten resin to mold a first layer 14A for covering the peripheries of the mutually joined parts of a plurality of the insert articles 11, 12 and 13 to fix the insert articles 11, 12 and 13 mutually by the first layer 14A and a molding process for molding the second layer 14B joined to at least either one of the insert articles 11, 12 and 13 and the first layer 14A to complete the insert molded article 10 are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert molding method and an insert molding apparatus for casting an insert with a resin.

[0002]

2. Description of the Related Art Conventionally, insert molding has been performed in which an insert made of metal or the like is placed in a cavity, and a molten resin is filled and hardened so that the insert is cast into a resin and molded into an integral composite part. Has been done.
By adopting such insert molding, it is possible to combine the performance of different materials to have a composite function, and to consolidate parts, shorten the process, and rationalize the assembly of the next process,
The stability of parts accuracy and the reliability of functions have been improved.

An example of insert molding is shown in FIG. Figure 3
In this gear component 100 shown in FIG. 2, a metal flange member 102 supporting a resin gear portion 101 and metal arc members 103 and 104 arranged on the inner circumference of the flange member 102 are inserted. ing. In the molding apparatus 110 shown in FIG. 3, a cavity 113 is formed between the upper and lower molds 111 and 112, and these inserts (flange member 102, arc-shaped members 103, 10) are formed.
Insert molding is performed by filling the molten resin into the cavity 113 in which 4) is sandwiched integrally.

Since the gear part 100 as described above is fixed to the member on the shaft side through the insert (flange member 102), the accuracy such as the coaxiality and straightness of the insert and the tooth profile is required. Therefore, in insert molding, it is important to accurately fix the insert to the mold.

[0005]

However, in the insert molding for manufacturing the gear part 100 having a plurality of such inserts, the inserts (flange member 102, arc-shaped members 103, 104) or the inserts ( Flange member 102, arc-shaped member 103,
104) is insufficiently abutted at the joint between the die and the mold, a gap is created in this portion and the resin wraps around,
There arises a problem that the strength of parts and the accuracy of shape are deteriorated. In order to prevent such a problem from occurring, the insert (flange member 102, arc-shaped members 103, 104) must be fitted to the mold, and therefore must be formed with extremely high precision. This is a problem in terms of manufacturing cost.

Further, since these inserts (arc-shaped members 103 and 104) are only sandwiched in the vertical direction, the arc-shaped member 1 is formed by the flow of the filled resin.
There is also a possibility that 03 will be pushed and it will shift from a predetermined position. Therefore, it is required to securely fix the inserts, but the mold structure that can fix the inserts having different shapes becomes complicated, and there is a problem that the manufacturing cost of the mold increases.

Moreover, the inserts that are only vertically sandwiched between the upper and lower molds 111 and 112 are inserts (flange member 102, arc-shaped members 103 and 104) when the molten resin is filled. Even if is accurately arranged, the resin contracts during cooling and moves as shown by the chain line in the figure. Since the amount of shrinkage increases as the thickness of the resin part increases, the positional deviation of such inserts increases, and cracks occur between the metal insert and the resin due to the difference in thermal expansion coefficient. As a result, it has been difficult to manufacture an insert-molded product with excellent component accuracy.

The present invention has been made in view of the above problems, and the inserts are accurately arranged without increasing the parts manufacturing cost and the mold manufacturing cost.
The objective is to obtain an insert molded product with excellent part accuracy.

[0009]

In order to solve the above-mentioned problems, in the insert molding method according to the invention of claim 1, a plurality of inserts are inserted in a state of being in contact with each other, and the periphery of the joint between these inserts. Is an insert molding method for molding an insert-molded product covered with molten resin, in which a plurality of inserts are integrally held at a predetermined position in a cavity, and the molten resin is filled in the cavity. Then, a first layer is formed to cover the periphery of the joint between the inserts, and the fixing step of fixing the inserts to each other by the first layer, and joining to at least one of the insert and the first layer. It is characterized by performing a molding step of molding the second layer and completing an insert-molded product.

According to the present invention, in the insert molding of casting a plurality of inserts, the fixing step of molding the first layer for fixing each insert and the second layer forming the outer shape of the product. Since the insert is fixed by a small amount of resin by performing the molding step separately from the molding step, it is possible to form an insert molded article that is less affected by shrinkage of the resin and has excellent positional accuracy of the insert. .

The insert molding apparatus according to the second aspect of the present invention molds an insert molded article in which a plurality of inserts are inserted in contact with each other and the periphery of the joint between the inserts is covered with the molten resin. An insert molding apparatus for forming a first cavity for integrally sandwiching a plurality of inserts therein and for molding a first layer covering a periphery of a joint between the plurality of inserts. A first mold for holding a preformed body composed of an insert and a first layer, and forming a second cavity for molding a second layer joined to the preformed body. It is characterized by having two molds.

According to the present invention, the insert molding apparatus for casting a plurality of inserts includes a first mold (first cavity) for molding for fixing the respective inserts and an outer shape of the product. By including the second mold (second cavity) for molding the second layer to be formed, a small amount of resin is filled in the first cavity,
The insert can be stably fixed in the first cavity,
It is possible to form a pre-molded article which is less affected by the shrinkage of the resin and has excellent shape accuracy. Further, in the second mold, since the pre-molded body accurately formed in the first cavity is insert-molded, it is possible to form an insert-molded article having excellent positional accuracy of the insert.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view showing an insert molded product 10 according to an embodiment of the present invention. The insert-molded product 10 includes a cup-shaped flange member (insert object) 11 having an oval hole 11a formed in the center thereof, and a first arc-shaped member (insert object) juxtaposed on the inner circumference of the flange member 11. ) 12 and the second arc-shaped member (insert) 13 are inserted. A resin portion 14 is formed on the outer periphery of these inserts (flange member 11, first arc-shaped member 12, second arc-shaped member 13).

The resin portion 14 includes inserts (flange member 11, first arc-shaped member 12, second arc-shaped member 13).
A first layer 14A that is molded to cover the periphery of the joint portion between them and fixes them, and the first layer 14A and each insert (flange member 11, first arc-shaped member 12, second arc-shaped member 13). And a second layer 14B which is joined to the pre-molded body 15 and which forms the outer shape of the insert-molded product 10. The first layer 14A and the second layer 14B are
Since they are made of the same material, they are integrated so that their boundaries cannot be identified.

2 (a) and 2 (b) are sectional views showing a mold provided in an insert molding apparatus 40 for molding the insert molded article 10 shown in FIG. Figure 2
The first mold 20 shown in (a) is composed of a fixed mold 21 and a movable mold 22 that is moved in the vertical direction in the figure. The drawing shows the mold closed time, and a first cavity 20C is formed between the fixed side mold 21 and the movable side mold 22.

The movable side die 22 has a first cavity 20.
A holding concave portion 22a that forms a part of C and holds the flange member 11 is formed.
On the lower surface of a, there is formed a fitting projection 22b which fits into an oval hole 11a provided in the center of the flange member 11 and positions the flange member 11 in the radial direction with respect to the mold. The fixed mold 21 is press-fitted by being fitted into the upper surface of the recess 21a forming a part of the first cavity 20C and being urged by the spring 24 toward the movable mold 22 (downward in the figure). A child 23 is provided. This press nest 2
3 presses the flange member 11 held by the movable mold 22 against the movable mold 22 when the mold is closed, so that the flange member 11 and the movable mold 22 and the flange member 11 and the first arc-shaped member 12 are pressed. The flange member 11,
The first arc-shaped member 12 and the second arc-shaped member 13 are sandwiched together, and a part of the first cavity 20C is formed.

In this first mold 20, the movable mold 22 is used.
Then, the oval hole 11a of the flange member 11 is fitted into the fitting convex portion 22b.
When the first and second arcuate members 12, 13 are placed on the inner circumference of the flange member 11 and the mold is closed, the first and second arcuate members 12, 13 are placed. Is pressed downward by the pressing insert 23, and the flange member 11, the first arc-shaped member 12, and the second arc-shaped member 13 are pressed.
Are integrally sandwiched between the molds 22 and 23. In this state, the first cavity 2 formed between the molds 22 and 23
By filling 0C with the molten resin, the flange member 1
The first layer 14 </ b> A that joins the first, first arc-shaped member 12, and second arc-shaped member 13 is molded, so that the pre-molded body 15 can be formed.

The lower wall surface 22 on the inner periphery of the holding recess 22a
c and the lower part of the outer periphery of the flange member 11 and the holding recess 2
The upper wall surface 22e on the inner periphery of 2a and the upper portion on the outer periphery of the flange member 11 do not need to be fitted together without a gap. That is,
Since these portions are not required to have the shape accuracy of the insert-molded product 10, even if the molten resin wraps around from the periphery such as between the inner wall surface 22d of the holding recess 22a and the outer periphery of the flange member 11, There is no particular problem. Therefore, it is not necessary to manufacture the flange member 11 with strict shape accuracy, and it is possible to manufacture the flange member 11 by pressing a plate material at low cost. In addition, since the shape accuracy of the flange member 11 is not required, the first arc-shaped member 1
2, the arrangement of the second arc-shaped member 13 varies,
The vertical variation of these members can be absorbed by the spring 24, and the radial variation of the pressing insert 23 is made to abut against the upper end surfaces of the first arc-shaped member 12 and the second arc-shaped member 13. That's fine, so it doesn't matter.

The second mold 30 shown in FIG. 2 (b) is composed of a fixed mold 31 and a movable mold 32 which is movable in the vertical direction in the figure. The figure shows when the mold is closed, and the second cavity 30C is formed between these molds. The movable mold 32 is provided with a holding recess 32a that forms a part of the second cavity 30C and holds the preformed body 15. The holding recess 32a has a lower surface on which the preformed body 15 is formed.
The fitting convex portion 32b is formed to fit into the oval hole 11a of the flange member 11 constituting the above and to position the flange member 11 (preformed body 15) in the radial direction with respect to the mold.

The fixed side mold 31 has a second cavity 30.
A pressing insert 33 is provided which is fitted into the upper surface of the concave portion 31a forming a part of C and is biased by the spring 34 toward the movable mold 32 (downward in the drawing). The press insert 33 is used for the pre-molded body 1 held by the movable mold 32.
When the mold is closed, the flange member 11 of No. 5 is pressed against the movable-side mold 32 so that the preformed body 15 and the movable-side mold 32 are brought into close contact with each other without a gap.

In this second mold 30, the preforming body 15 is put in the holding recess 32a of the movable mold 32, and the flange member 1
When the oval hole 11a of No. 1 is fitted into the fitting convex portion 32b and the preformed body 15 is arranged and the mold is closed, the flange member 11 is pressed downward by the pressing insert 33, and the preformed body 1
5 is sandwiched between both molds 32 and 33. In this state, the second cavity 30C formed between the molds 32 and 33 is filled with the molten resin to form the second layer 14B joined to the first layer 14A of the preform 15, and the insert is formed. It is possible to form the insert molded product 10 in which the product (the flange member 11, the first arc-shaped member 12, the second arc-shaped member 13) is cast in the resin portion 14.

A plurality of inserts (flange member 11, first arc-shaped member 12, second member) are formed by using the insert molding apparatus 40 having the first mold 20 and the second mold 30 configured as described above. Insert molding in which arc-shaped members 13) are inserted in contact with each other, and the periphery of the joint between these inserts (flange member 11, first arc-shaped member 12, second arc-shaped member 13) is covered with molten resin. A method of molding the product 10 will be described below.

First, a fixing step of fixing each insert (flange member 11, first arc-shaped member 12, second arc-shaped member 13) by the first layer 14A is performed. In the fixing step, as shown in FIG. 2A, the inserts (flange member 11, first arc-shaped member 12, second arc-shaped member 13) are integrally sandwiched at predetermined positions in the first cavity 20C. A first layer 14A that holds and fills the molten resin into the first cavity 20C to cover the periphery of the joint between the flange member 11, the first arc-shaped member 12, and the second arc-shaped member 13.
To mold. The first layer 14A only needs to be able to fix the inserts to each other, and preferably has a thickness such that the inserts do not shift due to contraction during resin cooling.

Next, a molding process for completing the insert molded product 10 is performed. In the forming process, as shown in FIG. 2B, the flange members 1 fixed to each other in the fixing process.
The preformed body 15 including the first, first arc-shaped member 12, the second arc-shaped member 13, and the first layer 14A is attached to the second cavity 30.
It is placed in C and the molten resin is filled in the second cavity 30C to form the first layer 14A and the second layer 14B joined to a part of the flange member 11. In the present embodiment, the second layer 14B is joined to a part of the pre-molded body 15 and the flange member 11, but at least one part of the inserts and the first layer 14A for fixing them, that is, the pre-molding. It may be joined to any part of the body 15. The first layer 14A and the second layer 14B
Are molded from the same resin, the second layer 14B
At the time of molding, the surface of the first layer 14A is melted and integrated so that the boundary cannot be discriminated.

In this way, by using the insert molding apparatus 40 of the present invention, the flange member 11, the first member 14 and the first member 14A and the second member 14B are formed by the resin portion 14.
It is possible to complete the insert molded product 10 in which the arcuate member 12 and the second arcuate member 13 are integrally cast.

The shapes and combinations of the constituent members shown in the above embodiment are merely examples, and can be variously changed based on design requirements and the like without departing from the spirit of the present invention. In the illustrated example, the first layer is formed on the outer peripheral side of the insert, and the second layer is further formed on the outer peripheral side of the first layer. However, the resin is bonded to the inner peripheral side or the inner peripheral side of the insert. May be

[0027]

As described above, according to the insert molding method of the first aspect of the present invention, the first layer for fixing inserts to each other in insert molding in which a plurality of inserts are cast. Since the insert is fixed with a small amount of resin by performing the fixing step for molding the resin and the molding step for molding the second layer that forms the outer shape of the product, the influence of resin shrinkage is small, It is possible to form an insert-molded product having excellent positional accuracy. Therefore, it is possible to easily manufacture a high-quality insert-molded product at low cost.

According to the insert molding apparatus of the second aspect of the present invention, the insert molding apparatus that casts a plurality of inserts around the first mold (first mold for performing molding for fixing the inserts together). Cavity) and a second mold (second cavity) for molding a second layer that forms the outer shape of the product
Since a small amount of resin is filled in the first cavity by including and, the insert can be stably fixed in the first cavity, the influence of resin shrinkage is small, and the shape accuracy is excellent. It is possible to form a preformed body. Further, in the second mold, since the pre-molded body accurately formed in the first cavity is insert-molded, it is possible to form an insert-molded article having excellent positional accuracy of the insert. Therefore, since it is not necessary to adopt a complicated structure in the mold for fixing the insert, the mold manufacturing cost can be suppressed, and a low-cost, high-quality insert-molded product can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an insert molded product formed by a molding method of the present invention.

FIG. 2 is a first mold (a) and a second mold provided in the insert molding apparatus according to the present invention, which realizes the fixing step of the present invention.
It is sectional drawing which shows an example of a metal mold | die (b).

FIG. 3 is a sectional view showing a conventional insert molding apparatus.

[Explanation of symbols]

10 Insert molded products 11 Flange member (insert) 12 1st circular member (insert) 13 Second arc-shaped member (insert) 14A First layer 14B second layer 15 Pre-molded body 20 First mold 20C 1st cavity 30 Second mold 30C second cavity 40 Insert molding machine

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Takeishi             3-1-1 Koganecho, Niigata City, Niigata Prefecture Mitsubishi             Niigata Works, Material Co., Ltd. F-term (reference) 4F206 JA07 JB12 JB22 JQ81

Claims (2)

[Claims] 1. An insert molding method for molding an insert-molded product, wherein a plurality of inserts are inserted in contact with each other, and a periphery of a joint between the inserts is covered with a molten resin, the method comprising: The plurality of inserts are held at a predetermined position in a state of being integrally sandwiched, and a molten resin is filled in the cavity to form a first layer covering a periphery of a joint between the inserts, Performing a fixing step of fixing the inserts to each other by a layer, and a molding step of molding a second layer joined to at least one of the insert and the first layer to complete the insert molded article. Characteristic insert molding method. 2. An insert molding apparatus for molding an insert molded article in which a plurality of inserts are inserted in contact with each other, and the periphery of the joint between the inserts is covered with molten resin, the insert molding apparatus comprising: A first mold for internally sandwiching the plurality of inserts, and forming a first cavity for molding a first layer covering a periphery of a joint between the plurality of inserts; A second mold for holding a pre-molded article composed of the object and the first layer therein and forming a second cavity for molding the second layer joined to the pre-molded article. Characteristic insert molding equipment.