JPH0232730A - Molding method - Google Patents

Abstract

PURPOSE:To prevent formation of burr on the surface of a metallic member by applying burr-preventive agent composed of resin or rubber dispersion or latex onto the surface of the metallic member across the border of a cavity. CONSTITUTION:Before a bracket 3 is set in a mold comprising upper and lower molds 11, 12, dispersion mainly composed of a copolymer of methacryl acid alkylester and acryl acid alkylester is applied uniformly across the border of a cavity 13 on the surface of the bracket 3 where a brush holder is formed, thus forming a burr-preventive agent coating film 15. The coating film 15 is also formed across the border of the cavity 13 on the surface of another metallic member i.e., a terminal member, to be inserted into the cavity 13 and applied with resin.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a molding method in which resin or rubber is used as a molding material, and particularly relates to a technique for preventing the occurrence of burrs in molded products. A bracket and brush holder composite (hereinafter referred to as a bracket unit) used in rotating electric machines such as It relates to effective techniques that can be used to mold things that are already being molded.

[Conventional technology]

As a bracket unit or two for use in a scooter motor, a bracket in which a brush holder is integrally molded using resin on a bracket formed into a thin plate shape has been proposed (for example, see Utility Model Application No. 59124482). ).

When molding this bracket unit, the following molding method is used.

That is, a cavity is formed in the mating surface of the upper mold and the lower mold in the mold so as to correspond to the brush holder. During molding of the brush holder, the bracket is placed and sandwiched between the mating surfaces of the upper mold and the lower mold so that a portion thereof is inserted into the cavity. Then, when a resin as a molding material is injected into the cavity through the gate, a bracket unit in which a part of the bracket is embedded in a resin-molded brush holder is molded.

(Problem to be solved by the invention) However, in such a molding method, the resin injected into the cavity leaks from between the mating surfaces of the upper mold and the lower mold, and the resin-molded brush holder A burr is formed from the outer periphery of the bracket to the surface of the bracket.

A first object of the present invention is to provide a method for molding a molded product in which a part of the metal member is implanted, which can prevent the formation of burrs on the surface of the metal member. It is in.

A second object of the present invention is to provide a molding method that can prevent burrs from forming on the outer periphery of a molded product in a molding method in which molding is performed using a mold having mating surfaces. There is a particular thing.

[Means to solve the problem]

A first molding method according to the present invention is that a part of the metal member is inserted into a cavity of a mold, and a resin or rubber is injected into the cavity to implant the part of the metal member. The molding method for molding a molded article is characterized in that an anti-burr agent made of resin or rubber dispersion or latex is applied to the surface of the metal member both inside and outside the boundary of the cavity.

A second molding method according to the present invention is a molding method for molding a molded article by injecting resin or rubber into a cavity formed in a mating surface of a mold, in which the cavity in the mating surface of the mold is An anti-burr agent made of resin or rubber dispersion or latex is applied around the opening edge of the opening.

[Function] According to the first means, the extremely fine gaps formed between the surface of the metal member and the mating surface of the mold are filled with the anti-blowing agent, so that the molding material in the cavity fills the gaps. leakage is prevented. Therefore, generation of burrs due to the leakage is prevented.

According to the second means, the extremely fine gaps formed in the mating surfaces of the molds are filled with the anti-blotting agent, so that the molding material in the cavity is prevented from leaking through the gaps. Therefore, generation of burrs due to the leakage is prevented.

〔Example〕

FIG. 1 is a longitudinal sectional view showing one step in a method for forming a bracket unit according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing another step, and FIGS. FIG. 2 is a perspective view and a vertical cross-sectional view showing a bracket unit as a product.

In this embodiment, the molding method according to the present invention is used to mold a bracket unit as a composite of metal and resin used in a starter motor. The bracket unit 1 that is the object of the molding includes a brush holder 2 as a resin structure integrally molded into a substantially disk shape from nylon resin, and the brush holder 2 is integrally molded with a bracket 3 as a metal member. . Further, a terminal member 4 as another metal member is implanted at a predetermined position of the brush holder 2 so as to pass through the bracket 3 in an insulated state, as shown in FIG. The bracket 3 is formed into a flat plate shape as shown in FIGS. 3 and 4 by punching and pressing a conductive plate material such as an iron plate. At both ends of the bracket 3, a pair of bolt insertion holes 3a and screw holes 3b are respectively arranged and opened.

A window hole 3C is formed approximately in the center of the bracket 3 so that the inner diameter is slightly larger than the outer diameter of a commutator (not shown), and a plurality of small holes 3e are formed around the window hole 3C. It is set up and arranged in the direction. A bearing member accommodating portion 3d is integrally connected to the window hole 3C in a circular bowl shape.

In addition, an insertion hole 3'' larger than the width and thickness of the terminal member 4 is opened at a predetermined position of the bracket 3.

In the molding method according to this embodiment, FIGS.
A mold 10 as shown in the figure is used. This mold 10 is equipped with an upper mold 11 and a lower mold 12, and a cavity 1 with a gate i4 is formed on the mating surfaces thereof.
3 is recessed in a shape that allows the brush holder 2 having the shape shown in FIGS. 3 and 4 to be formed.

Bracket 3 attaches brush holder 2 to this cavity 13.
The part of the window hole 3C to be molded is inserted and set so as to be sandwiched between the upper mold 11 and the lower mold 12.

At the same time, the terminal member 4 is inserted into the insertion hole 3r of the bracket 3 without contacting it, passes through the cavity 13, and is positioned and held by the upper mold 11 and the lower mold 12.

Here, before the bracket 3 is set in the mold 10, on the surface of the part of the bracket 3 where the brush holder 2 is to be molded, alkyl methacrylate/alkyl acrylate is formed so as to extend inside and outside the boundary of the cavity 13. A coating film 15 as a smear-preventing agent is formed by uniformly applying a dispersion containing an ester copolymer as a main component to an appropriate thickness using an appropriate means such as a brush or spray. The coating film 15 is also formed on the surface of the insert-molded portion of the terminal member 4, which is another metal member that is inserted into the cavity 13 and molded with resin, so as to extend inside and outside the boundary of the cavity 13. Ru.

A dispersion whose main component is an alkyl methacrylate/alkyl acrylate copolymer is an anti-scaling agent used to fill the extremely fine gaps formed between the surface of metal parts and the mating surfaces of the upper and lower molds. This is one example of a resin or rubber liquid material, and other resin or rubber dispersions, latex, etc. may also be used.

The thickness of the coating film 15 varies depending on the type of resin or rubber used, the type of dispersion or latex medium, emulsifier, etc., the concentration and viscosity of the liquid, etc.

Each time this coating film 15 is dried naturally or forcibly, water as a medium of the dispersion is appropriately evaporated. Then, this coating film 15 has rubber elastic properties or flexibility, and adheres to or sticks to the metal surface.

! ! ! After the IPI L 5 is dried, the bracket 3 and the terminal member 4 as metal members are set in the mold 10 as described above.

When the bracket 3 and the terminal member 4 are appropriately set in the mold 10 in this way, the nylon resin as the molding material is filled in the cavity 13 at a temperature of approximately 280°C.
The brush holder 2 as a resin structure made of nylon resin is integrally molded into the bracket 3, and the terminal member 4 is implanted into the brush holder 2. Ru.

That is, when the brush holder 2 is molded, the bracket 3 is arranged and implanted so as to be substantially perpendicular to the axis, so that the portion from the inner edge of the window hole 3c to the outside of the small hole 3e is attached to the front wall of the brush holder 2. It is integrated into the brush holder 2 while being sandwiched between the portion 2a and the rear wall portion 2b.

In this state, a part of the nylon resin forming the brush holder 2 fills each small hole 3e of the bracket 3 to form a solid cylindrical part 2c, and these cylindrical parts hold the bracket 3 and the brush holder together. 2 means that they are integrated in a state where they are completely prevented from rotating. Further, when the brush holder 2 is molded with resin, the terminal member 4 is fixedly held by a substantially rectangular parallelepiped-shaped holding portion 2d in which the insertion hole 3'' is filled with resin.

Flexibility is provided between the contact surfaces between the bracket 3 and the brush holder 2 on the front and rear surfaces of the bracket 3, the front and rear walls 2a and 2b of the brush holder 2, and the inner periphery of the small hole 3e and the outer periphery of the cylindrical portion 2c. A sealing film 16 is formed and interposed by a coating film 15 mainly composed of a methacrylic acid alkyl ester/acrylic acid alkyl ester copolymer. Since the seal 1FJ16 has a high affinity for resin, the seal 1FJ16 is strongly adhered or bonded to the surfaces of the bracket 3 and the brush holder 2, or is physically or chemically bonded to the surfaces thereof. Further, a sealing film 16 having a sufficient film thickness is similarly interposed between the contact surface between the brush holder 2 and the terminal member 4 inserted therein.

By the way, when molding a brush holder, if a coating film of anti-scaling agent is not formed on the surfaces of the bracket and terminal member, the nylon resin injected into the cavity will prevent the bracket and terminal member from mating with the upper and lower molds. It leaks from between the surfaces, and burrs are formed from the outer periphery of the resin-molded brush holder to the surfaces of the bracket and terminal member.

However, in the molding method, an anti-flash coating 11915 made of a dispersion of alkyl methacrylate/alkyl acrylate copolymer is formed on the surfaces of the bracket 3 and the terminal member 40 both inside and outside the boundary of the cavity 13. The extremely fine gaps formed between the surfaces of the bracket and terminal member and the molding die are filled with the coating film 15 of the anti-blowing agent. As a result, the nylon resin in the cavity is prevented from leaking through the gap, and the generation of burrs due to the leakage is inevitably prevented.

According to the first embodiment, the following effects can be obtained.

(1) In the method of molding a bracket unit, in which a bracket and a terminal member as metal members are implanted into a brush holder as a resin or rubber molded product, it is possible to prevent burrs from forming on the surfaces of the bracket and terminal member. Since this can be prevented, the performance such as the appearance of the bracket unit can be improved, and productivity can be significantly increased by omitting the deburring process.

(2) Dispersicon, a copolymer of methacrylic acid alkyl ester and acrylic acid alkyl ester, is used as an anti-fogging agent, and a coating film of this is applied to the entire surface of the bracket and terminal member corresponding to the part embedded inside the brush holder. A flexible sealing film made of resin or rubber that has good affinity for metals and resins is interposed between the contact surfaces of the bracket and terminal member and the brush holder. Therefore, even if a relative displacement occurs between the contact surfaces of the bracket and the terminal member and the brush holder due to a difference in coefficient of thermal expansion, the sealed state can be maintained.

Note that the present invention is not limited to the above embodiments,
It goes without saying that various changes can be made without departing from the gist of the invention.

For example, it is not necessary to form an anti-fogging agent coating on the entire surface of the bracket and terminal member that corresponds to the part that is implanted inside the brush holder, but at least on the surface of the bracket and terminal member that corresponds to the inside and outside of the cavity boundary. What is necessary is to form it partially in the area.

The bracket is not limited to being constructed using iron-based materials, but may be constructed using other metal materials, and the brush holder is not limited to being constructed using nylon resin, but may be constructed using other resins. You can.

FIG. 5 is a longitudinal sectional view showing one step in a method for molding an electromagnetic relay case according to another embodiment of the present invention, FIG. 6 is a longitudinal sectional view showing another step, and FIGS. 7 and 8 FIG. 2 is a bottom view and a vertical cross-sectional view showing an electromagnetic relay case which is a molded product thereof.

In Example 2, the molding method according to the present invention is used to mold a case for an electromagnetic relay. As shown in FIGS. 7 and 8, the case 21 to be molded includes a main body 22 formed of nylon resin into a substantially rectangular box shape with one end open, and a ceiling wall of the main body 22. It has a window hole 23 opened therein, and is configured to accommodate an electromagnetic relay (not shown) therein.

In the molding method according to the second embodiment, a mold 30 as shown in FIGS. 5 and 6 is used. This mold 30 includes an upper mold 31, a lower mold 32, and a core mold 33 attached to the lower mold 32.
A cavity 34 for forming the case 21 is formed by the core mold 33. Is the molding material placed in the cavity 34 in the upper mold 31? Gate 3 for mastering
5 have been established.

When the case 21 is molded using the mold 30, the upper mold 31 and the lower mold 32 are clamped.

Here, before the upper mold 31 and the lower mold 32 are clamped, the mating surfaces of the upper mold 31 and the lower mold 32, the lower mold 32 and the core mold 33,
A dispersion containing a methacrylic acid alkyl ester/acrylic acid alkyl ester copolymer as a main component is applied to the mating surfaces of the upper mold 31 and the core mold 33 by appropriate means such as brushing or spraying. A coating film 15A as an anti-blotting agent is formed in advance by uniformly applying the coating to an appropriate thickness.

The dispersion whose main component is alkyl methacrylate/alkyl acrylate copolymer is an anti-scaling agent that fills the extremely fine gaps formed on the mating surfaces of the upper mold, lower mold, and core mold. This is one example of a resin or rubber liquid material, and other resin or rubber dispersions, latex, etc. may also be used.

Painted! The thickness of 15 A varies depending on the type of resin or rubber II used, the dispersion or latex medium, the emulsifier, etc., the concentration and viscosity of the liquid, etc.

The coating film 15A is dried naturally or forcibly to appropriately evaporate water as a medium of the dispersion. Then, this coating film 15A has rubber elastic properties or flexibility, and adheres or adheres to the surface of each mold. After the coating film 15A is dried, the upper mold 31 and the lower mold 32 are matched.

When the mold 30 on which the anti-fogging agent coating 15A has been formed in this manner is clamped, nylon resin as a molding material is heated and melted at about 280°C in the cavity 34, and the gate 35 Filled from cavity 3
4, the case 20 described above is integrally molded.

By the way, in the case resin molding method, if a coating film is not formed on the mating surfaces of each mold, the nylon resin injected into the cavity will leak from between the mating surfaces of the winter mold, and the resin molded case will be damaged. A burr is formed on the outer periphery of the

However, in the molding method according to the second embodiment, a burr stopper made of a dispersion mainly composed of an alkyl methacrylate/alkyl acrylate copolymer is placed around the opening edge of the cavity 13 on the mating surfaces of each mold. Yaku-nuri Its! Since l 5△ is formed,
The extremely fine gaps formed on the mating surfaces of each mold are filled with the coating film 15A of anti-blowing agent. As a result, the nylon resin in the cavity is prevented from leaking through the gap, and the generation of burrs due to the leakage is inevitably prevented.

According to the second embodiment, the following effects can be obtained.

(1) In the molding method of molding a case as a resin or rubber molded product using resin, it is possible to prevent burrs from forming on the surface of the case.
In addition to improving the appearance and performance of the case,
By omitting the scraping process, productivity can be greatly increased.

FIG. 9 is a longitudinal sectional view showing one step in a lens unit molding method according to another embodiment of the present invention, FIG. 10 is a longitudinal sectional view showing another step, and FIGS. 11 and 12.
The figures are a partially omitted front view and side sectional view showing a lens unit that is a molded product.

In this embodiment, the molding method according to the present invention is used to mold a lens unit as a composite of resins used in lighting devices for automobiles, bicycles, etc.

The lens unit 41 to be molded includes a lens member 42 as a first resin member which is integrally molded into a desired lens shape from polymethyl methacrylate (hereinafter referred to as acrylic resin), and an acrylonitrile butadiene styrene polymer (hereinafter referred to as acrylic resin). Hereinafter, it will be referred to as ABS resin.

), and a ring 43 as a second resin member is integrally molded in a ring shape along the outer contour of the lens member 42.

When the ring 43 is molded using ABS resin, a part of the lens member 42 is implanted into a part of the ring member 42, so that the lens member 42 and the ring 43 are integrally combined. Lens unit 41 is molded. First, the lens member 42 is molded using acrylic resin as the molding material 14 .

In the molding method according to this example, FIG.
A mold 50 as shown in Figure O is used. This mold 50 has an upper mold 51 and a lower mold 52 of 61N, and a cavity 54 is provided on the mating surface of the upper mold and the lower mold.
The ring 43 is recessed into a shape capable of forming a ring 43 having the shape shown in FIGS. 11 and 12. Lower mold 52
A lens member holding portion 55 is already formed on the bottom surface of the cavity 54 so as to position and hold the lens member 42 molded using acrylic resin. Further, a gate 53 is provided in the upper mold 51 so that ABS resin as a molding material can be injected into the cavity 54.

Then, the pre-molded lens member 42 is positioned and held by the holding portion 55 of the lower mold 52 and is then centered. continue,
The upper mold 51 and the lower mold 52 are matched and clamped to form a cavity 54 for molding the lens member 42 and ring 43 in combination.

Here, before the lens member 42 is set in the lower mold 52, a methacrylic acid alkyl ester, acrylic acid, etc. The coating film 15B is formed by uniformly applying a dispersion containing an alkyl-ester copolymer as a main component to an appropriate thickness by an appropriate means such as a brush or spray.

A dispersion whose main component is a methacrylic acid alkyl ester/acrylic acid alkyl ester copolymer is an example of a resin or rubber liquid, and other resin or rubber dispersions or latexes may also be used. .

The thickness of the coating film 15B depends on the type of resin or rubber used,
It varies depending on the type of dispersion or latex medium, emulsifier, etc., the concentration and viscosity of the liquid, etc.
As shown in FIG. 13, it is applied to at least the depth of the groove 42a.

This coating film 15B is dried naturally or forcibly to appropriately evaporate water as a medium of the dispersion. Then, this coating 11915B has rubber elastic properties or flexibility, and also adheres or adheres to the surface of the resin. After the i film 15B is dried, the lens member 42 as the first resin member is placed in the mold 50 as described above.

When the lens member 42 and the mold 50 are appropriately set in this way, the cavity 54 is filled with ABS resin as a molding material through the gate 53 in a state heated and melted to a predetermined temperature, and the lens member 42 is A ring 43 as a second resin member made of ABS resin is integrally molded therein, and a lens member 42 is implanted into the ring 43.

Of course, the lens member 42 is placed and molded so as to be substantially perpendicular to the axis when the ring 43 is molded, so that the ring 43 is integrally molded along the outer edge of the rear surface. In this state, a part of the ABS resin forming the ring 43 is meshed with a part of the lens member 42, and this meshing part causes the lens member 42 and the ring 4 to
3 is completely combined and integrated.

A flexible sealing film 44 is formed between the contact surface between the I/lens member 42 and the ring 43 by a coating film 15 [3] whose main component is an alkyl methacrylate/alkyl acrylate copolymer. Because the methacrylic acid alkyl ester/acrylic acid alkyl ester copolymer has a high affinity for resin,
This sealing film 44 is integrated with the surfaces of the lens member 42 and the ring 43 by strongly adhering or bonding, or by being physically or chemically bonded.

By using a dispersion of methacrylic acid alkyl ester/acrylic acid algyl ester copolymer and forming a coating film of this on the part of the lens member that is implanted inside the ring, the contact surface between the lens member and the ring is improved. In between, a flexible sealing film made of resin or rubber that has good affinity for resin can be interposed, so that in the unlikely event that the lens member and the ring come into contact due to differences in thermal expansion coefficients, etc. Even if a relative shift occurs between the surfaces, the sealed state can be maintained.

Note that the present invention is not limited to the above embodiments,
It goes without saying that various changes can be made without departing from the gist of the invention.

The lens member is not limited to being made of acrylic resin, but may be made of other resins, and the ring is made of ABS.
The structure is not limited to using resin, but may be formed using other resins.

Further, by combining the first and second embodiments, it is possible to prevent the occurrence of burrs.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent the occurrence of burrs on the surface of a molded product, so that the appearance and other performance of the molded product can be improved as well as 1.
By omitting the scraping process, productivity can be greatly increased.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one step in a method for forming a bracket unit according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing another step, and FIGS. 3 and 4 are longitudinal sectional views showing another step. FIG. 2 is a perspective view and a vertical cross-sectional view showing a bracket unit that is a molded product. FIG. 5 is a longitudinal sectional view showing one step in a method for molding an electromagnetic relay case according to another embodiment of the present invention, FIG. 6 is a longitudinal sectional view showing another step, and FIGS. 7 and 8 FIG. 2 is a perspective view and a vertical sectional view showing an electromagnetic relay case which is a molded product thereof. FIG. 9 is a longitudinal sectional view showing one step in a lens unit molding method according to another embodiment of the present invention, FIG. 10 is a longitudinal sectional view showing another step, and FIGS. 11 and 12.
The figures are a partially omitted front view and side sectional view showing a lens unit that is a molded product. FIG. 13 is an enlarged partial sectional view showing the groove 42a. 1...Bracket unit, 2...Brush holder,
3... Bracket, 4... Terminal member, 10.
... Molding mold, 11... Upper mold, 12... Lower mold, 13.
...Cavity, 14...Gate, 15.15A.
... Anti-stick coating film, 16 ... Seal film, 21 ... Case, 22 ... Main body, 23 ... Window hole, 30 ... Molding mold, 31 ... Upper mold, 32 ...・Lower mold, 33... Core mold, 34... Cavity, 35... Gate, 41
... Lens unit, 42... Lens member, 43.
... Ring, 44 ... Seal membrane, 51 ... Upper mold, 5
2... Lower mold, 53... Gate, 54... Cavity, 55... Lens member holding part. Agent Patent Attorney Tatsuya KajiharaFigure 5Figure 7Figure 8Figure 11Figure 10Figure 12Figure 9

Claims (1)

[Claims] 1. A part of the metal member is inserted into a cavity of a mold, and a resin or rubber is injected into the cavity, thereby creating a molded product in which a part of the metal member is implanted. A molding method characterized in that a flash preventive agent made of resin or rubber dispersion or latex is applied to the surface of the metal member both inside and outside the boundary of the cavity. 2. In a molding method in which a molded product is formed by injecting resin or rubber into a cavity formed on a mating surface of a mold, resin or rubber is injected around the opening edge of the cavity on the mating surface of the mold. A molding method characterized by applying an anti-burr agent made of dispersion or latex. 3. The first resin member and a part of the first resin member are inserted into a cavity of a mold, and a part of the first resin member is implanted by injecting resin or rubber into the cavity. and a second resin member, in which a flash preventive agent made of a resin or rubber dispersion or latex is applied to the surface of the first resin member both inside and outside the boundary of the cavity. A molding method characterized by