JP4108565B2 - Synthetic resin coil spring manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a synthetic resin coil spring by injection molding, and a coil spring obtained thereby, which relates to a highly elastic coil spring that can be used in actual applications.

  Recently, products using synthetic resin molded products, such as automobiles and home appliances, can separate synthetic resin parts from metal parts such as springs and metal pieces, and recycle these at each raw material factory. Often required.

  For example, synthetic resin bottles containing cosmetic liquids and detergents are generally used as disposable containers. A nozzle having a small pump is provided at the head of the bottle, and the head of the nozzle is pressed to discharge a small amount of liquid corresponding to the stroke. A small coil spring made of stainless steel is used as an elastic member for restoring the plunger shaft constituting the small pump at the nozzle portion. In addition, in various synthetic resin toys, a metal coil spring is often used in a movable part that restores a movable part such as an arm in the same manner as described above.

  These bottles are often discarded after use, or in the case of toys, when they break down or are no longer needed, but these synthetic resin products contain a mixture of synthetic resin body parts and metal coil springs. Therefore, when it is discarded, it is assumed that these are disassembled and separated into synthetic resin and metal.

  However, in order to disassemble the nozzle part constituting the small pump at the head of the bottle, some technical knowledge and tools are necessary, and this disassembly operation is difficult for housewives and children. However, it is cumbersome and, therefore, there are many cases in which the synthetic resin portion of the outer portion such as the main body and the metal portion of the coil spring must be disposed in a mixed state. However, in the future, such disposal methods tend to be strictly regulated.

  On the other hand, the weight reduction of synthetic resin bottles and toys that contain liquids has been studied, and therefore, it has been desired to use synthetic resin springs instead of metal coil springs. Accordingly, a coil spring made of synthetic resin is necessary due to environmental restrictions when discarding the synthetic resin molded product and the problem of weight reduction of the bottle and toy.

  Synthetic resin coil springs are generally manufactured by manufacturing a thin rod with a circular cross section by an extrusion method, and a core rod made of a round bar that rotates in a softened state by reheating while it is in a softened state or after it is solidified ( A coil is formed while being wound around the surface of a mandrel, and this is cut into a predetermined length to complete one coil.

  However, synthetic resin coil springs made by this extrusion method are much less elastic than synthetic springs, so there are restrictions on their use as springs, and there are not many uses for them. It is.

  In addition, as a synthetic resin coil spring configured to increase the elastic force, a plurality of coil springs having the same length, the same turning direction, the same diameter, and the same pitch are arranged in parallel, and rings are arranged at both ends of each coil spring. There has been proposed a structure in which the end portions of these are integrally formed so as to be connected by the ring (for example, see Patent Document 1).

In addition, a synthetic resin thin-walled cylinder in which a cylindrical wall having through holes in the vertical direction and the horizontal direction is formed in a net shape at approximately equal intervals has been proposed (see Patent Document 2, for example).
JP-A-10-73138 Japanese Patent Laid-Open No. 9-291955

  Although it is not shown in the literature, it is a matter of course that only a circular cross section can be applied to a coil spring formed by winding an extruded wire rod around the surface of a mandrel, and the cross section is relatively large such as a rectangle. It is substantially difficult to change to one having a section modulus.

  For example, when a wire having a triangular or rectangular cross-section other than a circular cross-section is extruded and wound on a mandrel to form a coil, the wire can be accurately guided in a certain direction. In addition to being difficult, the cross-section is deformed or distorted from a predetermined cross section, which is unsatisfactory in appearance and it is difficult to manufacture a product having a predetermined spring characteristic. Furthermore, when a synthetic resin linear body molded into a circular cross-section is compared with a coil spring made of metal and a metal coil spring, the rigidity of the synthetic resin is weak compared to metals such as stainless steel. There is a drawback that only a very weak spring force can be exhibited.

  In addition, the synthetic resin spring described in Patent Document 1 is integrally molded into a shape in which rings at both ends of a plurality of coil springs are arranged, and rings are arranged at both ends and an intermediate portion of the plurality of coil springs. Although the one integrally formed in the shape has been proposed, the method of manufacturing this coil spring is not described at all, and it is unclear how it is manufactured.

  Furthermore, the invention described in Patent Document 2 is such that a cylindrical net-like material is molded from a synthetic resin and compressed in the length direction, and the compression coil spring of the pump for liquid discharge as described above However, this has the advantage that it can be discarded as it is without being separated when the synthetic resin product such as a liquid pouring pump is separated and discarded.

  However, the structure of the compression spring is extremely complicated. Therefore, the manufacturing method is complicated and it is difficult to efficiently obtain a compression spring having a predetermined compression strength.

  By the way, the biggest problem common to synthetic resin screws is that the rigidity of the synthetic resin, that is, the spring constant, is much lower than that of a metal screw. Therefore, if the spring is enlarged in order to compensate for this drawback, there is a disadvantage that the size of the spring is not suitable for the application.

  Even a coil spring manufactured using the same material can be mechanically strengthened by changing its cross section. For example, even if the outer diameter dimensions are the same, if the cross section is a circular shape and the width is a rectangular cross section, the elastic force is increased. Furthermore, when the height is made higher than the lateral width, the elastic modulus is further increased because the increase in the section modulus is considerably large. Furthermore, when reinforcing fibers such as carbon fibers or short fibers of glass fibers are mixed in the synthetic resin as the material, it is not difficult to produce an elastic force close to that of a metal.

  However, when a flat plate with a rectangular cross section is formed by extrusion molding and wound around the surface of the mandrel to form a coil spring, it is difficult to produce a precise shape due to twisting of the flat plate. Become. However, in the case of a plastic mixed with carbon fiber or glass fiber as described above, once cooled and solidified, the elastic force is improved at the stage of molding, so that rework becomes difficult.

  An object of the present invention is to solve the essential problem of the coil spring made of synthetic resin and to provide a spring made of synthetic resin having a large spring constant.

  The synthetic resin coil spring manufacturing method according to the present invention for achieving the above object is configured as follows.

1) a first mold material 2; a second mold material 3 that contacts and separates from the first mold material 2; a core 8 disposed on a joining surface of these mold materials 2 and 3; In the mold apparatus 1 in which a spiral cavity 6 is formed in the first mold material 2 and the second mold material 3, the first mold material 2 includes a slide core 2 c that moves parallel to the joint surface of the first mold material 2. , 2d and slide cores 3c, 3d that move parallel to the joint surface of the mold member 3, and the spiral cavity 6 includes a cavity on the mold member side that molds a predetermined length of the spiral. The first mold material 2 and the second mold material 3, the slide cores 2 c and 2 d provided on the first mold material 2, and the slide core provided on the second mold material 3, formed by a combination with a cavity on the slide core side On the outer peripheral top surface of the coil spring S formed by 3c and 3d A cavity 6 is formed so that parting lines of the adjacent mold materials are formed in series. Further, the cavity 6 is filled with a thermoplastic synthetic resin to form a coil spring S, and this thermoplastic synthetic resin is formed. After solidifying, the slide cores 2c, 2d, 3c, 3d are retracted with respect to the first mold material 2 and the second mold material 3, and then one or both of the first mold material 2 and the second mold material 3 are moved. The coil spring S is separated from the first mold material 2 and the second mold material 3 by moving in a direction intersecting the direction in which the slide core is moved .

2) The slide cores 2c, 2d, 3c, and 3d are characterized by being arranged at intervals of about 90 ° along the spiral cavity 6 .

In the following, technical information that is useful for carrying out the present invention will be briefly described.
A) The core 8 can be configured such that the inner surface of the coil spring S is formed and various members are integrally formed in a space formed inside the coil spring S.
B) A cylindrical body can be integrally formed in the space formed inside the coil spring S.
C) The coil spring obtained by the present invention is configured as follows.
(A) The coil spring X manufactured by injection molding of a thermoplastic synthetic resin can be provided with an additive in the central space.
(B) A base plate can be provided on at least one end of the coil spring.
(C) At least one of pitch, outer diameter, inner diameter, thickness, and cross-sectional shape can be changed in the length direction of the coil.
(D) A hook can be formed integrally with at least one end of the coil.
(E) A parting line of the mold material is formed at the top surface portion including the corner of the coil having a rectangular cross section .

  In the method of manufacturing a coil spring of a thermoplastic synthetic resin according to the present invention, a concave portion is formed on the mating surface of the divided mold material, and the core is closely accommodated in the concave portion. Then, a mold apparatus having a cavity for forming a coil spring on the mold material side is filled with injection molding of a molten thermoplastic synthetic resin, and the mold material is opened after the synthetic resin is cooled to a predetermined temperature. The synthetic resin coil spring is taken out together with the core.

Therefore, since the synthetic resin is manufactured by injection molding, it is possible to mass-produce highly accurate thermoplastic synthetic resin coil springs.
Further, the first mold material 2, the second mold material 3 contacting and separating from the first mold material 2, the core 8 disposed on the joining surface of these mold materials 2 and 3, and the periphery of the core 8, In the mold apparatus 1 in which a spiral cavity 6 is formed in the first mold material 2 and the second mold material 3, the first mold material 2 includes a slide core 2 c that moves parallel to the joint surface of the first mold material 2. , 2d are arranged in parallel with the joint surface of the second mold member 3, and the slide cores 3c, 3d are disposed, and the spiral cavity 6 is a cavity on the mold member side that molds a predetermined length of the spiral. And a cavity on the slide core side.
Further, a spiral cavity 6 constituting a coil spring S is formed on the joint surface between the mold members 2 and 3 and the slide cores 2c, 2d, 3c, and 3d supported by the mold members 2 and 3, as shown in FIG. , 6, 9 and 10, even if there are many undercut parts along the cavity of the mold, such as a coil spring having a rectangular cross section that is wider than the thickness, The coil spring that is a molded product can be released from the mold.
As described above, since various types of coil springs can be employed, even a synthetic resin coil spring can form a coil spring having various cross sections such as a rectangular cross section and a flat plate shape.
Accordingly, it is possible to form a coil spring having a large elastic coefficient and a strong elastic force compared to a conventional coil spring having a circular cross section, and it seems that it could not be used with a conventional synthetic resin coil spring manufactured by extrusion molding. Can be used for various purposes.
In addition, it has a thicker cross section than the width of the coil spring, and a highly elastic one can be manufactured .

According to the coil spring injection molding method of the present invention, the following can be manufactured according to the purpose.
a) Coil springs with unequal pitches, b) Coil springs with unequal thicknesses formed in the spirals, c) Coil springs in which protrusions and brackets are integrally formed in the middle of the length of the coil springs, d) Length Coil springs that can change the elastic force depending on the height of compression by producing coil springs with different thicknesses in the middle of the direction, e) Various kinds of additional materials such as rod-like objects that serve as stoppers, holding rods are passed inside the coil springs Pipe-shaped members and the like can be integrally molded, and can be provided with an extremely wide range of applications.
f) In particular, a coil spring in which fasteners such as hooks are integrally formed at both ends can be easily manufactured, which could not be manufactured with a conventional synthetic resin coil spring.
As described above, the coil spring manufactured according to the present invention can not only function as a mere coil spring, but also can integrally form a fixed portion in the middle of the coil spring.
In addition, a member having a function different from that of the coil spring, such as a base plate, a circular or square short shaft, a threaded portion, and a connecting portion with another member can be integrally formed at one end or both ends of the coil spring.
g) Moreover, the thing with the characteristic according to a use, such as a coil spring from which a diameter differs in a length direction and a coil spring from which a cross section differs in a length direction, can be shape | molded efficiently .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Coil spring that can be manufactured by the present invention)
First, the structure of a coil spring that can be manufactured according to the present invention will be described.

  FIG. 6 is a perspective view of a typical coil spring S that can be efficiently manufactured according to the present invention, and has a high elastic modulus such as polypropylene, polyester, or polycarbonate, and is injection-molded using a synthetic resin used for industrial applications. An example is shown. The coil spring S has, for example, a thin plate-like cross section with a thickness t of 2 mm and a width b of 5 mm, a spiral shape with an outer diameter of 45 mm and a pitch of 7 mm. Excellent spring characteristics can be exhibited by the improved elastic force due to the adoption.

  In addition, the spring in which this thin plate is injection-molded in a spiral shape has an effect that the elastic force can be stably exhibited even in a state of being almost compressed. Further, when completely compressed, there is an effect of acting as one cylindrical body.

  FIG. 7 shows a coil part c constituting the coil spring S1 and a cylindrical body B inside the coil part c arranged concentrically, and both are integrally injection-molded by a flange part f. At the end of the coil part c, FIG. The projection piece d that can be used as the fixing portion is formed. The projecting piece d is, for example, a member that transmits the elastic force of the coil part c to the other, and the cylindrical body B can be used when, for example, a support shaft or a guide member is passed through the cylindrical body B.

  As described above, the present invention can easily manufacture not only a coil spring but also a coil spring integrated with a member having another function.

  FIG. 8 is a front view of a standard coil spring S2, which has an outer diameter D, a thickness t that is relatively thick with respect to the width b, and a relatively large pitch p, and is elastically deformed. The one with the characteristic that the stroke can be enlarged and the relatively strong elastic force can be exhibited. The conditions and dimensions such as the various strokes and elastic forces can be arbitrarily designed.

  FIG. 9 shows various cross sections employed for the coil spring S2, where (a) is a vertical beam-shaped cross section, (b) is a horizontal beam-shaped cross section, (c) is a trapezoidal cross section, and (d) and (e) are The cross section (f) shows a chevron cross section. Unlike metal coil springs, these cross-sections are excellent in that the cross-section according to the application of the spring can be adopted by taking advantage of the characteristics of injection molding.

  FIG. 10 shows a special coil spring S3 having a large spring force that can be manufactured according to the present invention. The coil spring S3 has a width b wider than the thickness t, and end plates (or support plates) T are integrally formed at both ends. Thus, it is easy to support in a stable state. This structure can be used in the same manner as a long coil spring when used in a state in which a plurality of them are stacked.

FIG. 11 shows a modification of the coil spring of FIG. 9 and a simplified type in which the end plate T is omitted. When a plurality of the coil springs are used in parallel, they can be used for applications that receive a wide plane pressure.
(Mold structure)
FIG. 1 is a perspective view showing a main part of a mold apparatus for producing a synthetic resin coil spring according to the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a diagram showing a relationship between a mold material, a slide core, and a core. FIG. 4 is a side view showing a state where the target coil spring is taken out by retracting the mold material after removing the slide core. In this figure, the core is omitted.

  FIG. 5 is an exploded view of a mold member of an apparatus that further embodies the mold apparatus 1 shown in FIG. 1, in which parts to be integrated are integrated. Further, the core 8A is divided into two parts in the front-rear direction so that the coil spring S as a molded product can be easily taken out.

  The mold apparatus 1 according to this embodiment is an apparatus suitable for manufacturing a coil spring having a rectangular or flat cross-section or a ribbon-like cross section illustrated in FIGS. 6 to 11, and has a rectangular cross section or a flat cross section. A coil spring having a cross-sectional shape such as the above is accurately extracted from the mold without being deformed in cross-section.

  For example, in the case of a coil spring having a rectangular or flat cross section, when a cavity is formed in half on the joint surface of two commonly used molds, there is an “undercut portion” that does not adhere to the mold and cannot be removed. appear. This undercut part means that a part of the mold protrudes at the front part in the extraction direction of the molded product. Therefore, when manufacturing the mold, the movement direction of the mold and the coil spring It is necessary to design the mold so that there is no portion where the molded product is caught in relation to the extraction direction of the molded product having a complicated inclined surface.

  In that sense, in the present invention, the mold apparatus 1 is configured by a mold material composed of a combination of a first mold material (right mold or upper mold) and a second mold material (left mold or lower mold). The molds 2 and 3 having the foundation structure move in the lateral directions X1 and X2. The mold members 2 and 3 support slide cores 2c, 2d, 3c, and 3d that move to Y1 and Y2 in a direction different from this direction, and preferably in a vertical direction perpendicular to the direction. The first mold material 2 and the second mold material 3 are constituted by mold parts 2a and 2b, 3a and 3b, and the slide cores 2c, 2d, 3a and 3b.

  A mold apparatus 1 according to the present invention is composed of, for example, a first mold material 2 and a second mold material 3, and has through holes 5 (or recesses) formed on the mating surfaces of these mold materials 2 and 3. A cavity 6 for forming the coil spring S around is formed. A core 8 is disposed in the through hole 5, and a coil spring S is formed by a cavity 6 formed between the core 8 and the mold members 2 and 3.

  The first mold material 2 and the second mold material 3 move in one or both directions in the directions of the arrows X1 and X2 with the core 8 as the center. The core 8 is composed of upper, lower, left, and right central members, and is formed by removing the central member and removing the members having the upper and lower arcuate surfaces when the members on both sides are removed. The coil spring S can be taken out.

  In this embodiment, the first mold material 2 and the second mold material 3 are manufactured with two mold materials (2a, 2b and 3a, 3b) in order to facilitate the cutting of the curved surface of the coil spring-like cavity 6. These are formed into a single member by using an uneven fitting portion or a connecting plate. The first mold member 2 and the second mold member 3 are provided with slide cores 2c, 2d and 3c, 3d that move along the mating surfaces, respectively.

  The end portion of the slide core 2c is integrated with the connecting fitting 2e, and the end portion of the slide core 2d is integrated with the connecting fitting 2f, respectively, so that the opening operation is performed simultaneously as indicated by arrows Y1 and Y2. . This structure is similarly adopted on the second mold member 3 side.

  Therefore, in the molding process of the coil spring S, the through-hole 5 is formed by the first mold material 2 and the second mold material 3 and the slide cores 2c, 2d and 3c, 3d supported by the first mold material 2 and the second mold material 3. The wall surface of the spiral cavity 6 for forming the coil spring S is continuously formed around the round bar-shaped core 8 formed and disposed in the through hole 5.

In the case of the mold apparatus 1 shown in FIG. 5, the apparatus of FIG. 1 is remarkably simplified to improve the accuracy of the mold, and such a simple and durable apparatus is used for the actual apparatus. Is done.
(Shapes 2, 3 and slide core)
As can be understood with reference to FIG. 2 and FIG. 3, a mold member is arranged as follows in the middle of the thickness of the thin plate forming the coil spring S to form the cavity 6.

  1) A slide core 2c is fitted and arranged so as to move in the direction of arrow Y1 guided by a gap formed in the mold 2a and the mold 2a.

  2) The slide core 2d is fitted and arranged so as to move in the direction of the arrow Y2 guided by the gap formed in the mold 2b and the mold 2b.

  3) A mold member 3a, a slide core 3c that moves upward as indicated by an arrow guided by a gap formed in the mold member 3a, a mold member 3b, and a guide that is guided by a gap formed in the mold member 3b as indicated by an arrow. A slide core 3d that moves downward is fitted and disposed.

  Thus, the mold material forming one pitch of the coil spring S is composed of different mold materials in the range of 90 °, and in the thickness direction of the coil spring S, as shown in FIG. 3, the mold material 2b and the slide core 2d, A cavity 6 is formed by dividing the spiral in a range of 90 ° on the mating surface of the mold material 3b and the slide core 3d, the mold material 3a and the slide core 3a, and the mold material 2a and the slide core 2c.

  In this embodiment, because the undercut portion is formed every 90 ° because the coil spring S having a rectangular section wider than the thickness is formed, two types are formed every 90 °. The mold (combination of mold material and slide core) is arranged. As noted above, when paying attention to the coil spring S of 1 pitch p shown in FIG. 3, the portion formed by the slide core is arranged every 90 °, and the portion formed by the first mold material 2 and the second mold material 3 is the slide core. It is the part of every 90 ° following.

  A parting line is formed on the top surface of the coil spring S manufactured by the mold apparatus 1, and the first mold material 2 and the slide cores 2c and 2d, and the second mold material 3 and the slide core 3c are formed on the top surface. , 3d are facing each other.

  FIG. 4 shows a state in which the generated coil spring S is taken out from the mold apparatus 1 (the core 8 is omitted). As shown in FIG. 1, the mold materials 2a and 2b of the first mold material 2 and the slide cores 2c and 2d are assembled. Similarly, various mold materials of the second mold material 3 are gathered, and a spiral cavity 6 is formed around the core 8.

  When the mold apparatus 1 is in the assembled state in this way, molten resin is pressed into the mold apparatus 1 from a nozzle 10 (FIG. 1) connected to an injection molding machine (not shown), and a predetermined time is passed. When the mold is cooled to a predetermined temperature, each mold material is opened as shown in FIG. 1 and the coil spring S is molded around the core 8 and taken out. Then, the peripheral surface of the core 8 divided into a plurality in the length direction is reduced, and the coil spring S is taken out from the core 8.

  The synthetic resin used for the coil spring of the present invention can be an industrial resin having a high elastic modulus, such as polycarbonate, nylon, ABS, etc., but these resins are mixed with carbon fiber or glass fiber short fibers, and in some cases, metal whiskers. A coil spring having a higher repulsive force can be formed by injection molding using the raw material.

  FIG. 12 is a perspective view showing a method of forming the coil spring S5 by the mold apparatus 20 that does not use a slide core as shown in FIG. 1, and the spiral spring is formed between the core 8A and the eight-piece mold piece 21. FIG. A cavity is formed, and molten resin is injected and injected into the cavity to form the coil spring S5. In the case of this type of mold apparatus, the mold piece 21 divided into four or six can be used sufficiently.

  In the case of this mold apparatus 20, since a slide core is not used, a coil spring having a relatively large slope such as a trapezoid, a triangle, or a squirrel-like shape is used so that an undercut portion does not occur. It is suitable for an apparatus in the case of molding automatically.

  An example of a synthetic resin coil spring that can be manufactured according to the present invention is as follows.

  1) A coil spring having a cross section that cannot be manufactured by extrusion, such as a rectangular cross section having a flat cross section, a trapezoidal cross section, or a mountain cross section having a concave portion at the top (FIG. 9) can be easily manufactured.

  2) As shown in FIG. 7, a protruding piece d can be formed at the end of the coil spring S1, or an additive such as a cylindrical body B can be integrally formed inside the coil spring.

  3) As shown in FIG. 13, a member in which members having other functions such as fixing means such as hooks f are integrally provided at both ends of the coil spring S5 can be manufactured. FIG. 14 shows the cores 8B and 8b divided into two parts for forming the coil spring S5. After forming, the cores 8B and 8b are removed as shown by the arrows in FIG. The coil spring S5 can be taken out.

  4) A metal spring that can be used in the same manner can be manufactured. That is, as shown in FIG. 10 and FIG. 11, even coil springs S3 and S4 having a wider width can be manufactured compared to a thickness that cannot be manufactured by conventional molding methods. It is possible to easily produce a synthetic resin material with a high modulus of elasticity by mixing carbon fiber, glass fiber, or metal whisker and other reinforcing fibers into the material, and having the largest section modulus. is there.

  5) When the mold apparatus shown in FIG. 1 is used, a coil spring of unequal thickness, a coil spring S6 of unequal pitch (FIG. 15), and a member R (FIG. 16) for connecting the coil springs in the middle of the coil spring. The spring S7 provided with a portion that does not act as a coil spring, or a coil spring provided with a solid portion at the intermediate portion of the coil spring, or a coil spring provided with a fixing member at the end portion or intermediate portion of the coil spring can be integrally formed.

  In addition, as shown in FIG. 17, it is possible to manufacture a device having a function corresponding to various uses, such as a device in which a fixing member k2 and a base plate k1 each having a short axis projecting are provided at both ends of the coil spring.

  6) As the coil spring, a circular spiral shape is suitable for the processing convenience of the mold apparatus. However, the present invention is not limited to this, and various shapes such as a quadrilateral, a hexagonal shape, an octagonal shape and the like can be manufactured in plan view.

  7) For example, in the case of a coil spring having a rectangular cross section, as shown in FIGS. 10 and 11, it is possible to design and manufacture a spring having a greatly changed height / thickness ratio according to the application.

  In addition, a coil spring having a large elasticity compared to the width and having a large elastic force can be easily manufactured depending on the application.

It is a disassembled perspective view of the metal mold apparatus which combined the mold material and the slide core. It is the cross-sectional view cut | disconnected by the II-II line of the metal mold | die apparatus shown in FIG. It is sectional drawing of the metal mold apparatus shown in FIG. It is a side view which shows the relationship between a mold material and the shape | molded coil spring. It is a disassembled perspective view of the apparatus which simplified the metal mold apparatus shown in FIG. It is a perspective view of the coil spring which has a flat cross section. It is a perspective view of the coil spring which has a cylindrical body in the center part. It is a front view of a standard coil spring. (A)-(f) figure is various sectional drawing applied to the coil spring of FIG. It is a perspective view of a wide and large elastic spring that can be manufactured by the present invention. It is a perspective view of a wide and large elastic spring that can be manufactured by the present invention. It is a perspective view which shows the metal mold | die apparatus which does not use a slide core. It is a side view of the coil spring which formed the hook in both ends. It is a figure which shows the decomposition | disassembly core at the time of manufacturing the coil spring of FIG. It is a perspective view of the coil spring which has a different diameter and a different pitch. It is a perspective view of the coil spring which has a part which does not function as a coil in the middle part. It is a perspective view of the coil spring which provided the base etc. in the one end and provided the support plate etc. in the other end.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold apparatus 2 1st mold material 2a, 2b Mold material 3 2nd mold material 3a, 3B Mold material 2c, 2d, 3c, 3d Slide core 5 Through-hole, recessed part 6 Cavity 8 Core S-S8 Coil spring

Claims (2)

A first mold member 2, a second mold member 3 contacting and separating from the first mold member 2, a core 8 disposed on a joint surface between these mold members 2, 3, In a mold apparatus 1 in which a spiral cavity 6 is formed in a first mold member 2 and a second mold member 3,
The first mold 2 is provided with slide cores 2c and 2d that move parallel to the joint surface of the first mold 2 and slide cores 3c and 3d that move parallel to the joint surface of the mold 3. The spiral cavity 6 is formed by a combination of a cavity on the mold material side and a cavity on the slide core side for forming a predetermined length of the spiral,
The top of the outer periphery of the coil spring S formed by the first mold 2, the second mold 3, the slide cores 2 c, 2 d provided on the first mold 2, and the slide cores 3 c, 3 d provided on the second mold 3 A cavity 6 is formed on the surface so that parting lines of the adjacent molds are formed in series.
Furthermore, after filling the cavity 6 with a thermoplastic synthetic resin to form a coil spring S and solidifying the thermoplastic synthetic resin, the slide cores 2c, 2d, 3c, and 3d are connected to the first mold member 2 and the second mold material 2. Then, the coil spring S is moved backward with respect to the mold material 3, and one or both of the first mold material 2 and the second mold material 3 are moved in a direction intersecting the direction in which the slide core is moved. A method for manufacturing a synthetic resin coil spring in a mold apparatus, wherein the mold is separated from the second mold member 3 and the second mold member 3 . 2. The method of manufacturing a synthetic resin coil spring in a mold apparatus according to claim 1, wherein the slide cores 2c, 2d, 3c, and 3d are arranged along the spiral cavity 6 at about 90 [deg.] Intervals. .

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