JP3866018B2 - Molding method and molding device for cored elastic material coated ball - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to metal core and the molding method of the core containing the elastic material-coated balls coated with an elastic material such as rubber to the forming equipment.
[0002]
[Prior art]
Conventionally, cored coated balls that have a cored bar inside and are covered with rubber have been used for various types, for example, the movement of a ball-shaped valve element inserted inside a valve box Therefore, it is used as a valve body of a ball type check valve that prevents back flow of fluid. In this valve body, a metal cored bar is arranged at the center, and the periphery thereof is covered with rubber so as to be formed into a spherical shape.
[0003]
For example, when this ball type check valve is used in a manhole pump system, this check valve is provided on the discharge side of the submersible pump so that the amount of fluid such as sewage stored in the manhole is always constant. The check valve is closed after the pump is stopped and stopped after the pump is stopped to prevent backflow.
[0004]
Normally, the ball check valve for the manhole pump system uses a valve with a large flow path diameter, and the core of the valve body is a valve when the rubber-coated part is consumed and the ball diameter becomes small. The diameter is set so as not to jump out from the seating portion in the body or the ball guide on the secondary side into the flow path.
[0005]
When the check valve is used, it is used in a poor environment such as pumping sewage with a submersible pump, so foreign matter such as pebbles contained in the sewage may come into contact with the valve body and damage the rubber-coated part. It is installed in places where it is difficult to maintain due to wear and deterioration.
For this reason, the valve body is particularly required to have durability. At the time of molding, it is necessary to thicken the rubber-coated part or to uniformly mold the rubber-coated part in order to prevent deterioration.
[0006]
As a method for forming this ball-shaped valve body, a rubber cloth divided into a radial shape or an appropriate shape is temporarily attached to the surface of an inner core bar in advance, and then molded by compression vulcanization molding. There is a molding means.
[0007]
On the other hand, when the ball 22 is formed by transfer (injection) molding, which is one of press molding, a support rod 22 is provided near the lower part in the cavity of the molding die 20 as shown in FIG. A spherical metal core 23 is supported at the central portion in the cavity by the rod 22, and in this state, a rubber cloth 25 is press-fitted into the cavity through the pressure inlet 24 and molded. This transfer molding method is an effective molding method for pre-molding rubber material 25 such as compounded rubber or a vulcanized adhesive product with metal. It is generally used more than before. In this case, when the core metal 23 is supported in the cavity by the support rod 22 at the time of transfer molding, the core metal 23 is supported when the rubber fabric 25 is press-fitted so that the core metal 23 is supported by at least three support points. Has been kept stable.
[0008]
[Problems to be solved by the invention]
However, according to the former processing means by compression vulcanization molding, the cored bar is covered with the divided rubber dough, so it is difficult to make the thickness of the rubber dough uniform, It was difficult to provide at the central portion of the, and it took time and was a factor of cost increase.
[0009]
Also, according to this method, after compression vulcanization molding, the air that has entered between the rubber fabrics during temporary attachment may not escape, which may lead to inaccuracy as a product, or Non-defective products may occur.
[0010]
On the other hand, according to the latter molding means by conventional transfer molding, when the rubber fabric 25 is press-fitted, the rubber fabric 25 flows relatively easily up to the vicinity of the contact position between the molding upper mold 20a and the molding lower mold 20b. If it is below the molding lower die 20b below the central portion of the core metal 23, it is difficult to go around the core metal 23 due to the viscosity of the rubber cloth 25, and so-called overhang phenomenon may occur. For this reason, it is difficult for the rubber dough 25 to flow into the vicinity of the support rod 22 near the bottom surface of the cavity, and there are cases where voids are formed inside the ball 21 after molding or the surface is not completely covered.
[0011]
Further, even when the core metal 23 is supported using another support member (not shown), an overhang phenomenon occurs, so that it is difficult to uniformly coat the entire core metal 23 as shown in FIG. In addition, it is difficult to avoid leaving marks after the support member is removed at the contact position between the support member and the cavity.
[0012]
The present invention has led to the present invention in view of the above problems point, it is an object during the molding of the core containing the elastic material covering the ball, it can be molded with high precision elastic material-coated ball Furthermore, an object of the present invention is to provide an elastic material-coated ball containing a mandrel that can be mass-produced at a reduced cost, and a ball check valve using this ball .
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that an elastic material such as rubber is filled in a mold formed of an upper mold having a hemispherical upper gap and a lower mold having a hemispherical lower gap. A jig having a hemispherical core receiving part and a hemispherical outer peripheral surface to be brought into close contact with the gap, and disposed in a substantially concentric state in the spherical gap, After the spherical cored bar charged in the receiving part of the jig is disposed in a substantially concentric state in the gap together with the jig, and then filled with an elastic material in one of the upper and lower molds, In a state where the jig is removed from the gap and the semi-molded product in the gap is inserted, the remaining gap is filled with an elastic material, and the outer periphery of the metal core is uniformly coated with the elastic material together with the semi-molded product. This is a method for forming an elastic material-coated ball containing a cored bar.
[0014]
According to a second aspect of the present invention, a spherical cored bar is arranged in a substantially concentric state in the upper and lower gaps via the jig arranged in the lower gap of the lower mold, and then an elastic material is placed in the upper gap of the upper mold After that, after removing the jig, a semi-molded product in the upper gap is inserted into the lower gap, and an elastic material is further filled in the upper gap to surround the outer periphery of the core This is a method of molding an elastic material-coated ball containing a cored bar coated with an elastic material together with a molded product.
[0015]
According to a third aspect of the present invention, a spherical cored bar is arranged in a substantially concentric state in the upper and lower gaps via the jig arranged in the lower gap of the lower mold, and then an elastic material is placed in the upper gap of the upper mold. After that, after reversing the mold and removing this jig, the remaining gap is filled with an elastic material and the outer periphery of the core metal is covered with the elastic material together with the semi-molded product. This is a method for forming an elastic ball covered with an elastic material.
[0016]
The invention according to claim 4 is an apparatus for forming a cored elastic material-coated ball made up of a mold frame and a pressing member made up of an upper mold and a lower mold, wherein the upper mold and the lower mold have a hemispherical upper gap. Each of the lower gaps is formed to form a spherical gap, and the spherical cored bar is formed into a spherical shape through a jig having a hemispherical core receiving part and a hemispherical outer peripheral surface in close contact with the gap. Is arranged in a substantially concentric manner in the gap portion of the upper and lower molds and is filled with an elastic material in one of the upper and lower mold portions, and the outer periphery of the core metal together with the semi-molded product in a state where the jig is removed from the gap portion This is an apparatus for forming an elastic material-coated ball containing a cored bar, which forms a spherical elastic material-coated ball by filling and covering with an elastic material.
[0018]
【Example】
It will be specifically described below molding method of the core containing the elastic material-coated ball of the present invention as an embodiment of the forming equipment according to the drawings.
In FIG. 1, reference numeral 1 denotes a transfer-type molding apparatus main body comprising a mold frame 2 composed of an upper mold 2a and a lower mold 2b, and a pressing member 3 having a projecting pressing portion 3a. In the upper mold 2 a, 4 is provided in a concave shape so that the pressing portion 3 a can be inserted, and a pot 5 provided for injecting rubber 10 or resin, which is an elastic material, is suspended from the pot 4. The gate 5 is provided at a plurality of locations, and this gate 5 is provided so as to penetrate from the pot 4 to the upper gap portion 6a provided in a hemispherical concave shape on the lower surface of the upper mold 2a.
[0019]
After injecting an elastic material such as unvulcanized rubber 10 (hereinafter referred to as rubber) into the pot 4 and then pressing the pressing member 3 so as to insert the pressing portion 3a into the pot 4, the gate 5 It is possible to press-fit the rubber 10 from the upper gap portion 6a through the gap.
[0020]
The lower mold 2b is provided with a lower gap 6b formed in a hemispherical concave shape on the upper surface side, and when the upper mold 2a and the upper and lower gaps 6a, 6b of the lower mold 2b are combined, the spherical gap 6 is formed into a mold. 2 is formed so as to be molded in the space 2, and the space 6 can be used for spherical molding.
[0021]
7 is a spherical metal core formed into a spherical shape with metal or the like. When the metal core 7 is disposed inside the gap portion 6, a hemispherical shape that can be in close contact with the spherical surface portion of the metal core 7 . It is made of a heat-resistant material such as a metal having a receiving part 8a, and a cored bar 7 is attached to a cored bar holding jig 8, and the jig 8 on which the cored bar 7 is placed is mounted concentrically on the lower gap part 6b. Like to do. The spherical cored bar 7 is arranged concentrically in the spherical gap 6 by the inner and outer peripheral surfaces of the cored bar holding jig 8 , and the receiving part 8a is provided in a shape that allows the cored bar 7 to be attached and detached. When the cored bar 7 is placed on the jig 8, the outer peripheral surface of the lower hemisphere of the cored bar 7 is held. As described above, the jig 8 is configured to hold the spherical metal core 7 concentrically in the spherical gap 6 .
[0022]
FIG. 8 is a reference cross-sectional view showing a molding die 11 for finishing, and a rubber-coated ball 9 containing a core metal molded by the molding apparatus 1 is formed by a molding die 11 including an upper mold frame 11a and a lower mold frame 11b. It is sandwiched and vulcanized into a substantially spherical shape to improve the accuracy of the ball valve body.
[0023]
The ball 9 may be formed by appropriate processing by means such as manual operation or automation by computer control according to various factors such as the ball diameter and the number of valve bodies to be formed, and transfer. Of course, it can be applied not only to molding but also to injection (injection) molding.
[0024]
When the ball 9 with a cored bar in this example is used as a valve body of the ball check valve 12 having the flow path 13 in FIG. 10, for example, a desirable effect can be obtained.
[0025]
Next, the operation of the above embodiment will be described.
In this example, for example, the ball 9 of the check valve 12 when the nominal diameter of the flow path is 150 mm will be described and an example of the manufacturing process will be described. At this time, the ball 9 has a spherical diameter of about 180 to 190 mm, and the metal core 7 inside the ball 9 has a diameter of about 130 to 140 mm.
[0026]
At the time of molding the ball 9, first, the metal core 7 is previously placed on the receiving portion 8a of the jig 8, and in this state, the jig 8 is placed below the lower gap 6b of the lower mold 2b. After that, the mold 2 is formed by fitting the upper mold 2a to the lower mold 2b. In this case, the diameter of the gap 6 in the mold 2 is set to about 180 mm to 190 mm which is the diameter of the ball 9.
[0027]
Next, when the unvulcanized rubber 10 is injected 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, and as shown in FIG. 6 is filled. 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, an air vent hole may be provided in the mold 2 so that air in the gap 6 is extracted.
[0028]
FIG. 3 is a reference cross-sectional view showing a state in which the main body of the molding apparatus 1 of FIG. 2 is separated. Once the molding apparatus 1 is separated into an upper mold 2a and a lower mold 2b, the jig 8 is removed from the lower gap 6b. Further, the molded product in the upper gap 6 a rotates so as to be on the lower side, and is inserted into the gap 6.
[0029]
If the gap 6 is filled again with the rubber 10 in this state, a substantially spherical rubber-coated ball 9 can be obtained. It should be noted that the amount of rubber 10 injected into the pot 4 is adjusted as appropriate so that the rubber 10 does not remain after the pressing member 3 is pressed, or the amount necessary for molding the ball 9 does not become insufficient. To.
[0030]
Next, the molded ball 9 is taken out from the mold 2 and inserted into the molding die 11 to perform finish molding. In this finish molding, the rubber 10 is vulcanized so that the ball 9 has sufficient elasticity and strength as a valve body of the ball type check valve, and the accuracy such as sphericity is improved. Processing of the split surfaces (parting lines) of the molds 2a and 2b is also performed. The temperature of the rubber 10 at this time is a temperature at which a vulcanized state is reached, for example, about 160 ° C. The molding time is appropriately selected depending on the size of the ball 9 to be molded, the thickness of the rubber 10, and the like.
[0031]
According to the molding method of the ball 9 by the molding apparatus 1 of this example, the rubber 10 is installed so as to fill the upper gap portion 6 and the jig 8 is provided so as to be in close contact with the lower gap portion 6b. Therefore, when the rubber 10 is press-fitted from the gate 5, the gap 6 is filled on the upper gap portion 6 a side and does not flow into the lower side of the gap 6. Therefore, the rubber 10 does not cause overhang due to the viscosity of the rubber 10 and the rubber 10 is poured only in a natural direction. Defects such as voids and marks that functionally affect the surface can be made difficult to occur.
[0032]
Further, if the jig 8 is formed so that the center of the core bar 7 is positioned at the center of the gap 6 when the core bar 7 is attached, the core bar 7 can be easily and reliably secured to the central portion of the ball 9. Since the thickness of the rubber 10 can be made uniform, 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, the cored bar 7 is still in the gap 6 even if the jig 8 is slightly displaced in the circumferential direction. The balls 9 can be held concentrically, 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 manufactured at low cost.
[0033]
Further, the molding method according to the present invention is not limited to the form of the present example. For example, as shown in FIGS. 6 and 7, a pot 4 and a gate 5 are provided in both the upper mold 2a and the lower mold 2b, and the rubber 10 If the jig 8 is removed by reversing the top and bottom of the mold 2 after press-fitting from the gate 5 of the upper mold 2a, the lower mold 2b is separated and contacting the filled rubber 10 and the metal core 7. It is possible to mold without removing them and without taking them out.
In addition, said example shows an example, The magnitude | size of a non-return valve, a ball | bowl etc. shall be provided suitably according to implementation, and various embodiments are employable within the scope of the present invention. it can.
[0034]
【The invention's effect】
As apparent from the above, according to the present invention, it is possible to provide a molding method of the core containing the elastic material-coated ball can be molded with high precision elastic material covering the ball and its molding equipment.
[0035]
Furthermore, the molding process is easy and a uniform elastic material-coated ball can be manufactured, and a durable cored elastic material-coated ball can be obtained and overhang is caused by the viscosity of an elastic material such as rubber. Since the elastic material is poured only in a natural direction that does not occur, it is possible to uniformly form a cored ball over the entire ball.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an apparatus for forming an elastic material-coated ball containing a cored bar according to the present invention.
FIG. 2 is a reference cross-sectional view showing a state in which the pressing member of FIG. 1 is pressed.
FIG. 3 is a reference cross-sectional view showing a state where the molding apparatus of FIG. 2 is separated.
FIG. 4 is a reference cross-sectional view showing a state where a jig is removed.
FIG. 5 is a reference cross-sectional view showing a state where the pressing member of FIG. 4 is pressed.
FIG. 6 is a reference cross-sectional view showing another molding method in the present invention.
FIG. 7 is a reference cross-sectional view showing the process of FIG. 6;
FIG. 8 is a cross-sectional view showing a molding die.
FIG. 9 is a reference perspective view showing how the jig is attached.
FIG. 10 is a cross-sectional view showing an example in which the cored elastic material-coated ball of the present invention is applied to a ball check valve.
FIG. 11 is a cross-sectional view showing an example of a conventional molding apparatus.
FIG. 12 is a cross-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 2a Upper mold 2b Lower mold 3 Pressing member 3a Pushing part 6 Cavity 6a Upper gap 6b Lower gap 7 Core metal 8 Jig 8a Receiving part 9 Ball 10 Rubber 11 Mold 11

Claims (4)

  A method of forming a mold consisting of an upper mold having a hemispherical upper cavity part and a lower mold having a hemispherical lower cavity part by filling an elastic material such as rubber with a hemispherical core A jig having a hemispherical outer peripheral surface to be brought into close contact with the receiving portion and the gap portion is disposed in a substantially concentric state in the spherical gap portion, and a spherical core bar inserted into the receiving portion of the jig is Along with the jig, it is arranged in a substantially concentric state in the gap, and then, after filling one of the upper and lower molds with an elastic material, the jig is removed from the gap and the semi-molded product in the gap is mounted. An elastic material-coated ball including a cored bar, wherein the remaining gap is filled with an elastic material so that the outer periphery of the cored bar is uniformly coated with the elastic material together with the semi-molded product. Molding method.   A spherical cored bar is arranged in a substantially concentric state in the upper and lower gaps via the jig arranged in the lower gap of the lower mold, and then an elastic material is filled in the upper gap of the upper mold. After removing the tool, the semi-molded product in the upper gap is inserted into the lower gap, and further, the upper gap is filled with an elastic material, and the outer periphery of the core metal is covered with the elastic material together with the semi-molded product. The method for forming an elastic material-coated ball including a cored bar according to claim 1.   The spherical cored bar is arranged in a substantially concentric state in the upper and lower gaps through the jig arranged in the lower gap of the lower mold, and then an elastic material is filled in the upper gap of the upper mold, and then the mold 2. The cored elasticity according to claim 1, wherein in a state in which the jig is removed, an elastic material is filled in the remaining gap, and the outer periphery of the cored bar is covered with an elastic material together with the semi-molded product. Method for forming material-coated balls.   An apparatus for forming a cored elastic material-coated ball composed of a mold consisting of an upper die and a lower die and a pressing member, and forming a hemispherical upper gap portion and a lower gap portion in the upper die and the lower die, respectively. The spherical cored bar is made substantially concentric in the spherical gap through a jig having a spherical gap and having a hemispherical core receiving part and a hemispherical outer peripheral surface closely contacting the gap. The elastic material is filled in one of the upper and lower cavities, and the outer periphery of the metal core is filled and covered with the semi-molded product with the jig removed from the gap. An apparatus for forming an elastic material-coated ball including a cored bar, which forms a spherical elastic material-coated ball.

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