JP2002018890A - Method and apparatus for molding elastic material- covered ball with core metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding an elastic material-covered ball with a core metal which enables molding of the elastic material-covered ball of high precision and moreover enables mass production thereof at a reduced cost. SOLUTION: An elastic material such as a rubber 10 is filled in a frame composed of a top force 2a having a semispherical upper vacant space part 6a and of a bottom tool 2b having a semispherical lower vacant space part 6b and is molded therein. In this method, the spherical core metal 7 is disposed in a substantially concentric state in the upper and lower vacant space parts 6a and 6b and the rubber 10 is filled subsequently in the vacant space part 6 in either of the top force and the bottom tool 2a and 2b. Then, the rubber 10 is filled in the vacant space part 6 of the other so that it covers the outer periphery of the core metal 7 equally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for forming a core-coated ball coated with an elastic material in which a core is coated with an elastic material such as rubber. The present invention relates to a suitable molding method and a molding device.

[0002]

2. Description of the Related Art Conventionally, a cored metal-coated ball having a cored bar inside and covered with rubber has been used in various types, for example, a ball-shaped ball inserted into a valve box. Is used as a valve element of a ball-type check valve in which the backflow of fluid is prevented by the movement of the valve element. In this valve element, a metal core is disposed at the center, and the periphery thereof is covered with rubber to be formed into a spherical shape.

When this ball type check valve is used in, for example, a pump system for manholes, the check valve is provided on the discharge side of a submersible pump so that fluid such as sewage stored in the manhole is constantly maintained at a constant amount. As a result, the pump is pumped, and after the pump is stopped, the check valve is closed to prevent backflow.

Normally, a ball check valve for a manhole pump system has a large flow path diameter.
The core metal of the valve body is formed to have a diameter that does not protrude from the seat portion in the valve body or the ball guide on the secondary side into the flow path when the ball diameter is reduced due to wear of the rubber-coated portion. .

When the check valve is used, it is used in a poor environment such as pumping sewage with a submersible pump. Therefore, foreign matters such as pebbles contained in the sewage may come into contact with the valve body to prevent the rubber coating portion from being used. Is gradually deteriorated due to damage or wear, and is installed in places where maintenance is difficult. For this reason, the valve body is particularly required to have durability, and it is necessary to thicken the rubber-coated portion at the time of molding or to uniformly mold the rubber-coated portion to prevent deterioration.

[0006] As a method of forming the ball-shaped valve element, a rubber material divided radially or in an appropriate shape is temporarily attached to the surface of an inner metal core in advance, and then compression vulcanization molding is performed. There is a forming means adapted to be formed.

On the other hand, when the ball 22 is formed by transfer (injection type) molding, which is one of press molding, as shown in FIG. 11, a support rod 22 is provided near a lower portion in a cavity of a molding die 20. A spherical metal core 23 is supported at the center of the cavity by the support rod 22, and in this state, a rubber material 25 is pressed into the cavity through the press-in port 24 and molded. This transfer molding method is an effective molding method for a rubber material 25 having a complicated preform such as a compounded rubber or a vulcanized adhesive product with a metal. It has been commonly used in the past. In this case, at the time of supporting the core bar 23 in the cavity by the support rod 22 during transfer molding, the core bar 23 is supported at least by three or more supporting points so that the core bar 23 is pressed when the rubber material 25 is pressed. Is trying to maintain a stable state.

[0008]

However, according to the former processing means by compression vulcanization molding, since the core metal is covered so that the divided rubber materials are combined, the thickness of the rubber material is made uniform. It is difficult, and it is difficult to provide a core metal at the center of the ball,
Eventually, this was a factor of cost increase.

Further, according to this method, after the compression vulcanization molding, the air which has entered between the rubber materials during the temporary attachment may not escape, and as a result, the accuracy of the product may deteriorate, In some cases, defective products occurred.

On the other hand, according to the former transfer molding method, when the rubber material 25 is press-fitted, the rubber material 25 flows relatively close to the contact position between the upper mold 20a and the lower mold 20b. Easy, but core 2
When it is below the lower molding die 20b below the central portion of 3, the viscosity of the rubber material 25 makes it difficult for the rubber material 25 to go under the cored bar 23, and a so-called overhang phenomenon may occur. Therefore, the support rod 22 near the bottom surface of the cavity
In some cases, the rubber dough 25 hardly flows into the vicinity, resulting in voids inside the ball 21 after molding, or the surface may not be completely covered.

In addition, even when the core bar 23 is supported by using another support member (not shown), the overhang phenomenon occurs. Therefore, as shown in FIG. And it is difficult to avoid leaving a mark after removing the support member at the contact position between the support member and the cavity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of forming a cored elastic ball coated with a high-precision elastic material coated ball. An object of the present invention is to provide a core-coated elastic material-coated ball that can be mass-produced at a reduced cost.

[0013]

In order to achieve the above object, the invention according to claim 1 is directed to a mold comprising an upper mold having a hemispherical upper cavity and a lower mold having a hemispherical lower cavity. Is a method of filling and molding an elastic material such as rubber, wherein a spherical metal core is disposed substantially concentrically in the upper and lower gaps,
After filling the elastic material in one of the upper and lower mold cavities, the elastic material is filled in the cavity of the other mold so that the outer periphery of the core is evenly covered with the elastic material. This is a method of forming a material-coated ball.

According to a second aspect of the present invention, there is provided a method of forming a core-coated elastic material ball in which the core-coated elastic material-coated ball is further subjected to spherical molding by a molding die.

According to a third aspect of the present invention, a spherical core is disposed substantially concentrically in the upper and lower gaps via an appropriate jig disposed in the lower gap of the lower mold. After the jig is removed, the semi-molded product in the upper space is charged into the lower space, and the elastic material is further filled in the remaining space to remove the outer core. This is a method of forming a core-coated elastic material-coated ball whose periphery is coated with an elastic material.

According to a fourth aspect of the present invention, a spherical core is disposed substantially concentrically in the upper and lower voids via an appropriate jig disposed in the lower void of the lower die. Filling the void with the elastic material, then turning the mold over and removing the jig, filling the remaining void with the elastic material and covering the outer periphery of the core with the elastic material This is a method of forming an elastic material-coated ball.

According to a fifth aspect of the present invention, there is provided an apparatus for forming a core-coated elastic material-coated ball comprising a pressing member having a pressing portion and a mold frame including an upper die and a lower die. The upper space portion and the lower space portion are each formed in a hemispherical shape, and an elastic material is filled in each of the upper space portion and the lower space portion in a state where the spherical core metal is arranged substantially concentrically in the space portion. This is a molding device for a core-coated elastic material-coated ball for forming a ball coated with an elastic material such as rubber.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a molding method and an apparatus for molding a core-coated elastic material ball according to the present invention. In FIG. 1, reference numeral 1 denotes a transfer-type molding apparatus main body including a mold frame 2 including an upper mold 2a and a lower mold 2b, and a pressing member 3 having a protruding pressing portion 3a. In the upper mold 2a, 4 is provided in a concave shape so that the pressing portion 3a can be inserted, and a pot 5 provided for injecting a rubber 10 or a resin which is an elastic material is provided. The gate 5 is provided at a plurality of locations, and the gate 5 is provided so as to penetrate from the port 4 to a concave upper gap portion 6a provided in a hemispherical shape on the lower surface of the upper mold 2a.

After an elastic material such as rubber 10 in an unvulcanized state is injected into the pot 4, the pressing member 3 is pressed by inserting the pressing portion 3 a into the pot 4. The rubber 10 can be press-fitted from 6a.

The lower mold 2b is provided with a hemispherical lower cavity 6b in a concave shape on the upper surface side, and the cavity 6a of the upper mold 2a and the lower mold 2b is formed.
When the 6b is combined, a spherical cavity 6 is provided in the mold frame 2 so that spherical molding can be performed.

Numeral 7 is a metal core formed into a spherical shape by a metal or the like. When the metal core 7 is disposed inside the cavity 6, a receiving portion 8a which can be in close contact with the surface of the metal core 7 is provided. The core metal 7 is attached to a jig 8 made of a heat-resistant material such as metal.
Is attached to the lower gap 6b. This jig 8
Thereby, the core metal 7 is arranged substantially concentrically in the gap 6. The receiving portion 8 a is provided with the core 7 in a detachable shape, and holds the central portion of the lower hemisphere of the core 7 when the core 7 is placed on the jig 8. Also, jig 8
The member is not limited to this example, and may be any member as long as the core metal 7 is concentrically held in the gap 6.

FIG. 8 is a reference cross-sectional view showing a molding die 11 for finishing, in which a rubber-coated ball 9 containing a metal core formed by the molding apparatus 1 is formed by an upper molding frame 11a and a lower molding frame 11b. It is sandwiched by the mold 11 and vulcanized and formed into a substantially spherical shape so as to improve the accuracy as a ball valve body.

The ball 9 may be formed by manual operation or by computer-controlled automation according to various factors such as the ball diameter and the number of valve elements to be formed. In addition, the present invention can be applied not only to transfer molding but also to injection (injection) molding.

The ball 9 in this embodiment is, for example, as shown in FIG.
When used as the valve element of the ball check valve 12 having the flow path 13 in the above, a desired effect can be obtained, but the present invention is not limited to this and can be applied to various types.

Next, the operation of the above embodiment will be described. In this example, for example, the nominal diameter of the flow path is 150 mm
An example of the manufacturing process will be described using the ball 9 of the check valve 12 in the case of. The ball diameter of the ball 9 at this time is
The diameter of the metal core 7 inside the ball 9 is about 130 to 140 mm.
About.

When molding the ball 9, first, the core metal 7
Is mounted on the receiving portion 8a of the jig 8, and in this state, the jig 8 is attached to the lower cavity 6b of the lower die 2b with the jig 8 on the lower side, and then the upper die 2a is attached to the lower die 2b. The mold 2 is molded in accordance with the requirements. In this case, the diameter of the cavity 6 in the mold 2 is about 180 mm to 190 mm which is the diameter of the ball 9.
mm.

Next, when the rubber 10 in an unvulcanized state is poured into the pot 4 of the upper mold 2a and the pressing member 3 is pressed, the rubber 10 is pressed into the gap 6 from the gate 5 as shown in FIG. Is filled in the gap 6. The temperature of the rubber 10 at this time is a temperature in an unvulcanized state, for example, about 110 ° C. In order to facilitate the injection of the rubber 10, the gap 6
The mold 2 may be provided with an air vent hole so as to release the air inside.

FIG. 3 is a reference sectional view showing a state in which the main body of the molding apparatus 1 of FIG.
The jig 8 is separated from the lower mold 2b and the jig 8 is removed from the lower gap 6b, and the molded product in the upper gap 6a is rotated downward so as to be inserted into the gap 6.

In this state, when the rubber 6 is filled in the void portion 6 again, a substantially spherical rubber-coated ball 9 can be obtained. The injection amount of the rubber 10 into the pot 4 is appropriately adjusted so that the rubber 10 does not remain after the pressing of the pressing member 3 or the amount necessary for molding the ball 9 is not insufficient. To

Next, the molded ball 9 is taken out of the mold frame 2 and inserted into a molding die 11 to carry out finish molding. In this finish molding, the rubber 10 is vulcanized to ensure that the ball 9 has sufficient elasticity and strength as a valve body of the ball type check valve, while improving the accuracy such as sphericity and the like. Processing of the parting line (parting line) of the mold 2a and the lower mold 2b is also performed. The temperature of the rubber 10 at this time is a temperature at which the rubber 10 becomes a vulcanized state, for example, about 160 ° C. The molding time is
It is appropriately selected according to the size of the ball 9 to be molded, the thickness of the rubber 10, and the like.

According to the method of molding the ball 9 by the molding apparatus 1 of this embodiment, the rubber 10 is set so as to fill the upper space 6 and the jig 8 is brought into close contact with the lower space 6b. When the rubber 10 is press-fitted from the gate 5, the rubber 10 is filled in the upper gap portion 6 a side of the gap portion 6,
It does not flow below the gap 6. Therefore, rubber 1
No overhang occurs due to the viscosity of 0, and the rubber 10 is poured only in a natural direction that is reasonable. Defects such as voids and marks that affect the above can be made less likely to occur.

If the jig 8 is formed so that the center of the core bar 7 is located at the center of the gap 6 when the core bar 7 is mounted, the core bar 7 can be easily and reliably connected to the ball 9. And the thickness of the rubber 10 can be made uniform, so that the ball 9 with high accuracy can be formed. In addition, since the substantially dish-shaped jig 8 is concentrically arranged in the gap 6, even if the jig 8 is slightly shifted in the circumferential direction, the core metal 7 is still placed in the gap 6. The ball 9 can be held in a concentric state, and the ball 9 can be formed with high accuracy. Furthermore, since automatic production by computer control is possible, the balls 9 can be mass-produced while improving the yield, and can be produced at low cost.

The molding method according to the present invention is not limited to the form of the present embodiment. For example, as shown in FIGS. 6 and 7, both the upper mold 2a and the lower mold 2b are provided with the pot 4 and the gate 5 as shown in FIGS.
If the rubber 10 is pressed into the gate 5 of the upper mold 2a and then the mold 2 is turned upside down and the lower mold 2b is separated and the jig 8 is removed, the filled rubber 10 and Molding can be performed without contacting the cored bar 7 and without removing them. The above examples are merely examples, and the size of the check valve, the ball, and the like are appropriately provided according to the implementation, and various embodiments may be adopted within the scope of the present invention. it can.

[0034]

As is apparent from the above, according to the present invention, there is provided a method for forming a core-coated elastic material-coated ball capable of forming a high-precision elastic material-coated ball, and at the same time, cost reduction. Thus, it is possible to provide a molding method that can be mass-produced.

Further, a uniform elastic material-coated ball which is easy to form can be manufactured, and a durable core-coated elastic material-coated ball can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an apparatus for forming a core-coated elastic material-coated ball according to the present invention.

FIG. 2 is a reference sectional view showing a state where a pressing member of FIG. 1 is pressed.

FIG. 3 is a reference sectional view showing a state in which the molding apparatus of FIG. 2 is separated.

FIG. 4 is a reference sectional view showing a state where a jig is removed.

FIG. 5 is a reference sectional view showing a state where the pressing member of FIG. 4 is pressed.

FIG. 6 is a reference sectional view showing another molding method according to the present invention.

FIG. 7 is a reference sectional view showing a step of FIG. 6;

FIG. 8 is a sectional view showing a molding die.

FIG. 9 is a reference perspective view showing a mounting state of a jig.

FIG. 10 is a cross-sectional view showing an example in which the elastic material-coated ball of the present invention is applied to a ball check valve.

FIG. 11 is a sectional view showing an example of a conventional molding apparatus.

FIG. 12 is a sectional view showing an example of a conventional molding apparatus.

FIG. 13 is a bottom view showing a conventional covered ball.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding apparatus main body 2 Mold frame 2a Upper die 2b Lower die 3 Pressing member 3a Pressing part 6 Gap part 6a Upper gap part 6b Lower gap part 7 Core 8 Jig 8a Receiving part 9 Ball 10 Rubber 11 Molding mold

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 22 B29K 105: 22 B29L 9:00 B29L 9:00 31:54 31:54 F term (reference) 3H058 AA04 BB29 CA22 4F202 AA45 AD03 AD18 AG19 AH13 CA12 CB01 CB17 CQ03 CQ05 4F204 AA45 AD18 AG19 AH13 EF37 EF49 FA01 FB01 FB12 FN11 FN17 FQ01 FQ15 4F206 AA45 AD03 AD18 AG19 AH12 JA02 J02

Claims (5)

[Claims] 1. A method comprising: filling a mold comprising an upper mold having a hemispherical upper cavity and a lower mold having a hemispherical lower cavity with an elastic material such as rubber; The gold is disposed substantially concentrically in the upper and lower gaps, and then the elastic material is filled in one of the upper and lower mold cavities, and then the elastic material is filled in the other mold cavities and the outside of the core metal. A method of forming a core-coated elastic material-coated ball, wherein the periphery is uniformly covered with an elastic material. 2. The molding method according to claim 1, wherein the core-coated elastic material-coated ball is further subjected to spherical molding with a molding die. 3. A spherical core is disposed substantially concentrically in the upper and lower voids via an appropriate jig disposed in the lower void of the lower die, and then, an elastic material is filled in the upper void of the upper die. After that, after removing the jig, the semi-molded product in the upper gap portion is charged into the lower gap portion, and the remaining gap portion is filled with an elastic material, and the outer periphery of the core metal is covered with the elastic material. Claim 1
Or a method of forming the core-coated elastic material-coated ball according to 2 above. 4. A spherical metal core is disposed substantially concentrically in the upper and lower voids via an appropriate jig disposed in the lower void of the lower die, and then an elastic material is placed in the upper void of the upper die. The core according to claim 1 or 2, wherein after filling, the mold is turned over, the jig is removed, and the remaining void is filled with an elastic material to cover the outer periphery of the core metal with the elastic material. Molding method for gold-coated elastic material balls. 5. An apparatus for forming an elastic material-coated ball containing a metal core comprising a pressing member having a pressing frame and a mold frame comprising an upper die and a lower die, wherein the upper die and the lower die have a hemispherical upper void portion. An elastic material such as rubber is filled by filling an elastic material into each of the upper gap and the lower gap in a state where the lower gaps are respectively formed and the spherical core metal is arranged substantially concentrically in the gaps. An apparatus for forming an elastic material-coated ball containing a core metal, wherein the coated ball is formed.