JP2009000901A - Molding apparatus and molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding apparatus and a molding method, wherein the dimensions and weight of a molded article can be stabilized. <P>SOLUTION: The molding apparatus 10 constituted so that an unvulcanized rubber material supplied into a cavity 11 is molded into the molded article having an external shape formed along the inside surface of the cavity 11 and then the molded article W is withdrawn from the cavity 11 as it is unvulcanized, is provided with: an injection molding machine 21 for injecting the unvulcanized rubber material of a fluidized state into the cavity 11; and a cooling means 27 for cooling the rubber material injected into the cavity 11 in the cavity 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molding apparatus and a molding method in which an unvulcanized rubber material supplied into a cavity is molded into an outer shape along the inner surface shape of the cavity, and then the molded product is taken out of the cavity in an unvulcanized state. Is.

For example, in a rubber crawler, a driving projection protruding on the inner peripheral surface and meshing with a driving wheel and a driven wheel, a lug protruding on the outer peripheral surface, or a lug protruding on the tread portion of a large tire, for example, As shown in Patent Document 1 below, first, an unvulcanized rubber material supplied into the cavity is molded into an outer shape along the inner surface shape of the cavity, that is, the shape of the drive protrusion, lug, etc. The molded product may be formed by removing the molded product from the cavity without being vulcanized, and then vulcanizing the molded product together with other members to integrally form them.
By the way, conventionally, the unvulcanized rubber material supplied into the cavity has been extruded or rolled into a shape close to the product shape, and this preformed product is supplied to the cavity and compressed. It was molded into the final shape before vulcanization.
Japanese Patent Laid-Open No. 10-100300

  However, in the conventional molding apparatus and molding method, even if the preform is compressed in the cavity and molded into the final shape before vulcanization, the molded product returns to the original shape when the mold is opened. As a result, the dimensional accuracy may not be stable. Furthermore, if the weight of the pre-formed product varies during extrusion or rolling, which is a pre-process of this molding, this variation may be reflected as it is on the molded product formed by the molding apparatus.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a molding apparatus and a molding method capable of stabilizing the size and weight of a molded product.

In order to solve the above-described problems and achieve such an object, the molding apparatus of the present invention forms an unvulcanized rubber material supplied into the cavity into an outer shape that conforms to the inner shape of the cavity. And a molding apparatus for taking out the molded product from the cavity in an unvulcanized state, an injection molding machine for injecting the unvulcanized rubber material in a fluid state into the cavity, and being injected into the cavity And a cooling means for cooling the rubber material in the cavity.
According to this invention, since the injection molding machine and the cooling means are provided, after injecting the unvulcanized rubber material in a fluid state into the cavity, the rubber material is put into the cavity before opening the mold. Thus, the outer shape of the molded product can be quickly and accurately fixed to the inner shape of the cavity. Therefore, it is possible to form a molded product with stable dimensional accuracy, improve the product quality regardless of the appearance and the inside, and further improve the manufacturing efficiency.
Further, the rubber material injected into the cavity by the cooling means can be immediately cooled, and the rubber material can be prevented from inadvertently vulcanizing in the cavity. Thereby, it becomes possible to suppress the partial burning of the molded product, and the product quality of the molded product can be stabilized.
Moreover, since the rubber material in a fluid state is directly injected into the cavity to form a molded product without going through an extrusion process or a rolling process before this molding process, the pre-formed product formed in the previous process is For example, it is possible to prevent variations in weight or the like from being reflected in the molded product formed in this molding process. In particular, when the injection molding machine is provided with a weighing means capable of measuring the weight of the rubber material in a fluid state before being injected into the cavity, the weight of the rubber material injected into the cavity is stabilized. This makes it possible to further improve product quality.

Here, when the temperature of the rubber material injected into the cavity reaches a preset temperature, or when a preset time has elapsed after the rubber material is injected into the cavity, the cavity is opened. And a control unit for taking out the molded product.
In this case, it is possible to reliably achieve the above-described effects and to prevent the molded product taken out from the cavity from being deformed, and it is possible to reliably form a highly accurate molded product.

The inner diameter of the nozzle hole of the injection molding machine may be 4.5 mm or more and 5.5 mm or less.
In this case, when the rubber material passes through the nozzle hole, it is possible to give the rubber material sufficient fluidity to spread evenly throughout the entire area of the cavity, and the rubber injected into the cavity. It is possible to reliably suppress the temperature of the material from rising to such an extent that vulcanization is started in the cavity.

In the molding method of the present invention, after the unvulcanized rubber material supplied into the cavity is molded into an outer shape along the inner surface shape of the cavity, the molded product is taken out from the cavity in an unvulcanized state. An injection step of injecting an unvulcanized rubber material in a fluid state in the cavity; a cooling step of cooling the rubber material injected in the cavity in the cavity by a cooling means; It is characterized by having.
According to this invention, the dimension and weight of a molded product can be stabilized.

  According to this invention, the dimension and weight of a molded product can be stabilized.

Hereinafter, an embodiment of a molding apparatus 10 according to the present invention will be described with reference to FIGS. 1 and 2.
The molding apparatus 10 includes a mold 12 having a cavity 11 to which an unvulcanized rubber material is supplied, and unillustrated taking-out means for taking out a molded product W from a cavity forming portion 14a of an upper mold 14 to be described later. Then, after molding the unvulcanized rubber material supplied into the cavity 11 into an outer shape along the inner surface shape of the cavity 11, the molded product W is taken out from the cavity 11 in an unvulcanized state. .

  The take-out means can take out the molded product W on the cavity forming portion 14a by sucking it from the outside of the opening 13 in the opening direction. Further, as a molded product W molded by the molding apparatus 10, a rubber crawler used by being wound in an endless belt shape between a driving wheel and a driven wheel is projected on an inner peripheral surface so as to project from the driving wheel and the driven wheel. Examples thereof include a driving projection that meshes with a driving wheel, a lug projecting on the outer peripheral surface, or a lug projecting on the tread surface portion of a large tire. In the illustrated example, a molding apparatus 10 that molds the driving projection of a rubber crawler is provided. The inner surface of the cavity 11 has a shape along the outer shape of the drive protrusion.

  Here, in the present embodiment, the mold 12 is constituted by a pair of molds 14 and 15 each having mold surfaces 14 b and 15 b extending in a direction along the opening surface of the opening 13. The molds 14 and 15 are provided such that they can be relatively advanced and retracted in a direction perpendicular to the opening surface so that the respective mold surfaces 14b and 15b are in contact with and separated from each other. In addition, each mold 14 and 15 has a cavity forming portion that opens to the respective mold surfaces 14b and 15b and forms the cavity 11 when the mold surfaces 14b and 15b are in contact with each other and clamped. 14a and 15a are formed separately. The cavity forming portions 14a and 15a are opened at the center in the creeping direction on the mold surfaces 14b and 15b.

Hereinafter, of these molds 14 and 15, the mold having the opening 13 is referred to as an upper mold 14, and the mold having the bottom 16 of the cavity 11 is referred to as a lower mold 15. In the illustrated example, the lower mold 15 is supported by the base 28 from the surface side opposite to the mold surface 15 b, and the base 28 moves forward and backward toward the upper mold 14. The lower mold 15 is also moved forward and backward toward the upper mold 14.
Here, the cavity 11 is gradually reduced in diameter from the opening 13 toward the bottom 16. In this embodiment, the cross-sectional view shape along the opening surface of the cavity 11 is a square shape in which the corners are convex curved surfaces.

 Furthermore, in this embodiment, the fitting convex part 17 which protruded toward the mold surface 15b of the lower mold 15 is formed on the mold surface 14b of the upper mold 14. A fitting recess 18 into which the fitting projection 17 is fitted when the mold is clamped is formed on the mold surface 15 b of the lower mold 15. A cavity forming portion 14 a of the upper mold 14 is opened on the top surface 17 a of the fitting convex portion 17, and a cavity forming portion 15 a of the lower mold 15 is opened on the bottom surface 18 a of the fitting concave portion 18.

 Furthermore, the fitting convex part 17 is gradually diameter-reduced as it goes to the top surface 17a from the metal mold | die surface 14b of the upper side metal mold | die 14. As shown in FIG. Further, the fitting recess 18 is gradually reduced in diameter as it goes from the mold surface 15b of the lower mold 15 to the bottom surface 18a. In addition, the fitting convex part 17 and the fitting recessed part 18 are respectively arrange | positioned rather than the outer periphery of the metal mold | die surfaces 14b and 15b in a creeping direction inner side.

In this embodiment, the molding apparatus 10 includes an injection molding machine 21 that injects an unvulcanized rubber material that is in a fluid state in the cavity 11, and the rubber material that has been injected into the cavity 11. A cooling means for cooling and a hot platen (not shown) are provided.
The inner diameter of the nozzle hole 21a of the injection molding machine 21 is 4.5 mm to 5.5 mm.

 Here, the molding apparatus 10 further includes a runner mold 26 provided in the upper mold 14 so as to be movable back and forth with respect to the surface opposite to the mold surface 14b. The runner mold 26 has a runner 26 a that communicates with the cavity 11 through the opening 13 when the runner mold 26 contacts the opposite surface of the upper mold 14. The runner 26a is also opened on the surface of the runner mold 26 opposite to the surface in contact with the upper mold 14. The nozzle hole 21a of the injection molding machine 21 passes through the opening of the runner 26a and the opening 13 of the cavity 11 in this order through the opening of the runner 26a on the opposite surface of the runner mold 26. It is supposed to be able to communicate with.

 In the present embodiment, the cooling means includes a refrigerant passage 27 formed in the lower mold 15 and a refrigerant supply means (not shown). The refrigerant supply means has a constant temperature ( For example, a refrigerant having a temperature of about 30 ° C. is supplied, and the refrigerant that has been heated through the passage 27 is collected and the temperature is lowered. Then, the refrigerant is supplied to the refrigerant passage 27 again.

  Here, in this embodiment, a temperature sensor 23 such as a thermocouple is embedded in the pair of molds 14 and 15, and the temperature of the rubber material in the cavity 11 can be measured by the temperature sensor 23. It has become. In the illustrated example, the temperature sensor 23 is embedded in the vicinity of the cavity forming portion 14 a inside the upper mold 14.

 Further, in this molding apparatus 10, after injecting a rubber material into the cavity 11 from the injection molding machine 21, based on the output signal from the temperature sensor 23, the runner mold 26, the injection molding machine 21, and the base 28. And a control unit 24 for driving the take-out means. The injection molding machine 21 is provided with a measuring means (not shown) capable of measuring the weight of the rubber material in a fluid state before being injected into the cavity 11.

Next, a method for forming the molded product W using the molding apparatus 10 configured as described above will be described.
First, the mold surface 14b of the upper mold 14 and the mold surface 15b of the lower mold 15 are brought into contact with each other to form the cavity 11, and the runner mold 26 and the injection molding machine 21 are moved upward. It moves forward toward the mold 14, and the nozzle hole 21a of the injection molding machine 21 and the cavity 11 are communicated with each other through the runner 26a and the opening 13. At this time, the fitting convex portion 17 is fitted into the fitting concave portion 18. Then, an unvulcanized rubber material in a fluid state is injected into the cavity 11 from the nozzle hole 21 a of the injection molding machine 21 through the runner 26 a and the opening 13. The injection flow rate of the rubber material from the nozzle hole 21a at the time of injection is about 80 m ³ / s, and the injection temperature of the rubber material is set to about 90 ° C., for example.
Here, in the process up to here, the inside and the inner surface of the cavity 11 are cooled by the cooling means.

  After that, the control unit 24 receives an output signal from the temperature sensor 23 in a state where the above-described mold clamping is held, and when the temperature based on the signal is lowered to a preset temperature, the control unit 24 Signals are transmitted to the drive means of the base 28, the runner mold 26, the injection molding machine 21 and the take-out means. Then, the runner mold 26 and the injection molding machine 21 are moved backward from the molds 14 and 15, and the base 28 is moved backward from the upper mold 14 together with the lower mold 15 to move both mold surfaces 14 b and 15 b. The molds are opened apart from each other. The time from the completion of injection to the mold opening is about 1.5 minutes to 3.3, for example, when the internal volume of the cavity 11 is about 500 cc and the total flow rate of the refrigerant passing through the refrigerant passage 27 is about 25L to 51L. Set to 0 minutes.

  Here, since the inner surface shape of the cavity 11 is reduced in diameter as described above, when the mold is opened, the molded product W in the cavity 11 is the cavity forming portion of the upper mold 14 of both the molds 14 and 15. 14a remains. Then, the take-out means provided outward in the opening direction of the upper mold 14 is moved forward toward the opening 13, and the molded product W in an unvulcanized state is moved out of the opening 13 in the opening direction. Is sucked from the side and taken out from the cavity forming portion 14a.

 As described above, according to the molding apparatus 10 according to the present embodiment, since the injection molding machine 21 and the cooling means are provided, after injecting the unvulcanized rubber material in a fluid state into the cavity 11, This rubber material can be forcibly cooled and hardened in the cavity 11 before opening the mold, and the outer shape of the molded product W can be quickly and accurately fixed to the inner surface shape of the cavity 11. Can do. Therefore, the molded product W can be formed with stable dimensional accuracy, the product quality can be improved regardless of the appearance and the inside, and the manufacturing efficiency can be improved.

Furthermore, the rubber material injected into the cavity 11 can be immediately cooled by the cooling means, and the rubber material can be prevented from inadvertently vulcanizing in the cavity 11. Thereby, it becomes possible to suppress the partial burning in the molded product W, and the product quality of the molded product W can be stabilized.
In addition, since the rubber material in a fluid state is directly injected into the cavity 11 to form the molded product W without going through an extrusion process or a rolling process before the molding process, the pre-molding formed in the previous process is performed. It is possible to prevent variations in the product, such as weight, from being reflected in the molded product W formed in this molding process. In particular, in the present embodiment, the injection molding machine 21 is provided with a weighing means capable of measuring the weight of the rubber material in a fluid state before being injected into the cavity 11, so that the rubber material injected into the cavity 11 can be measured. The weight can be stabilized and the product quality can be further improved.

  Further, in this embodiment, the control unit 24 is provided in the molding apparatus 10, and when the temperature of the rubber material injected into the cavity 11 reaches a preset temperature, the cavity 11 is opened and the molded product W is opened. Since it is designed to be taken out, it is possible to reliably achieve the above-mentioned effects and to prevent the molded product W taken out from the cavity 11 from being deformed, thereby reliably forming a highly accurate molded product W. can do.

 Furthermore, in this embodiment, since the inner diameter of the nozzle hole 21a of the injection molding machine 21 is 4.5 mm or more and 5.5 mm or less, when the rubber material passes through the nozzle hole 21a, It is possible to provide sufficient fluidity to spread evenly throughout the entire area of the inside of the cylinder 11, and the temperature of the rubber material injected into the cavity 11 rises to such an extent that vulcanization is started in the cavity 11. Can be reliably suppressed.

 Furthermore, in the present embodiment, the mold surfaces 14b and 15b extending in the direction along the opening surface of the opening 13 and the cavity formation that opens in the mold surfaces 14b and 15b and forms the cavity 11 when the mold is clamped. A pair of molds 14 and 15 each having a portion 14a and 15a are provided, and the cavity 11 is gradually reduced in diameter from the opening 13 toward the bottom 16, so that after molding, the respective mold surfaces 14b and 15b When the molds 14 and 15 are driven so as to be spaced apart from each other in a direction orthogonal to the opening surface, the molded product W has the opening 13 of the pair of molds 14 and 15. It can be left on the cavity forming portion 14 a of the upper mold 14. Therefore, it is possible to clarify the location of the molded product W when the mold is opened, and it is possible to eliminate an obstacle to automating the molding process.

 Moreover, when the mold is opened, the molded product W is separated from the cavity forming portion 15a of the lower mold 15 of the pair of molds 14 and 15, and is in contact only with the cavity forming portion 14a of the upper mold 14. Therefore, the contact area between the molds 14 and 15 and the molded product W when the mold is opened can be reduced as compared with that before the mold is opened, and the molded product W can be easily taken out from the mold. Can do. Therefore, it becomes possible to suppress deformation of the molded product W when the molded product W is taken out from the molds 14 and 15, and the dimensional accuracy of the molded product W can be improved. The manufacturing time can be shortened.

 Further, in the present embodiment, the fitting convex portion 17 is gradually reduced in diameter as it goes from the die surface 14 b of the upper die 14 to the top surface 17 a, and the fitting concave portion 18 is a die of the lower die 15. Since the diameter gradually decreases from the surface 15b toward the bottom surface 18a, one of the pair of molds 14 and 15 is displaced in the direction along the opening surface with respect to the other in the mold open state. Even in the case, in the process of clamping the mold, this positional shift can be corrected by the side surface 17b of the fitting convex portion 17 slidingly contacting the side surface 18b of the fitting concave portion 18. Therefore, it is possible to form a molded product W having high accuracy and excellent appearance quality over a long period of time, and the number of maintenance steps for the mold apparatus 10 can be reduced.

 Furthermore, in the present embodiment, the pair of molds 14 and 15 can be relatively advanced and retracted in the direction perpendicular to the opening surface so that the respective mold surfaces 14b and 15b abut and separate from each other. Since it is provided, the above-mentioned action and effect are surely achieved.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the coolant passage 27 is formed only in the lower mold 15, but may be formed only in the upper mold 14, or may be formed in both molds 14 and 15, respectively. Also good. Further, instead of this, for example, a coolant passage 27 may be provided in the base 28 or the runner mold 26 to cool the inside and the inner surface of the cavity 11. Furthermore, a refrigerant passage 27 may be provided in the heating plate.

Moreover, the fitting convex part 17 and the fitting recessed part 18 do not need to be provided. Further, in the above-described embodiment, the lower mold 15 is moved forward and backward with respect to the upper mold 14 to clamp and open the mold, but conversely, the upper mold 14 may be moved forward and backward. Alternatively, both molds 14 and 15 may be moved forward and backward.
Furthermore, the molding apparatus 10 according to the embodiment is not limited to the driving projection of the rubber crawler, but can be applied to the case of molding a lug such as a rubber crawler or a large tire.

 Moreover, in the said embodiment, although the temperature sensor 23 was embed | buried in the metal mold | die 14 and 15, this temperature sensor 23 is not provided, but after inject | pouring the rubber material in the cavity 11 by the control part 24, the preset time When lapse of time, the runner mold 26 and the injection molding machine 21, the base 28, and the take-out means may be driven to open the cavity 11 and take out the molded product W.

Furthermore, in the embodiment, the configuration in which the molded product W on the cavity forming portion 14a is sucked and taken out from the outside in the opening direction of the opening portion 13 as the taking-out means has been shown. After the molds 14 and 15 are opened, the molded product W may be removed by pressing or hitting from the top surface 17a side of the upper mold 14.
In the above-described embodiment, the mold 12 includes a pair of molds 14 and 15 each having the mold surfaces 14b and 15b extending in the direction along the opening surface of the opening 13. Instead of this, for example, a configuration composed of a pair of molds each having a mold surface extending along a direction orthogonal to the opening surface of the opening 13 may be adopted.

 The dimension and weight of the molded product can be stabilized.

It is a longitudinal cross-sectional view which shows the state clamped in the shaping | molding apparatus shown as one Embodiment which concerns on this invention. It is a longitudinal cross-sectional view which shows the state which opened the mold in the shaping | molding apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Molding apparatus 11 Cavity 21 Injection molding machine 21a Nozzle hole 24 Control part 27 Refrigerant passage (cooling means)
W molded product

Claims (3)

A molding apparatus for taking out the molded product from the cavity in an unvulcanized state after molding the unvulcanized rubber material supplied into the cavity into an outer shape along the inner surface shape of the cavity,
An injection molding machine for injecting an unvulcanized rubber material in a fluid state in the cavity;
And a cooling means for cooling the rubber material injected into the cavity in the cavity. The molding apparatus according to claim 1,
When the temperature of the rubber material injected into the cavity reaches a preset temperature, or when a preset time has elapsed after the rubber material is injected into the cavity, the cavity is opened to form a molded product. A molding apparatus comprising a control unit for taking out the product. A molding method in which an unvulcanized rubber material supplied into a cavity is molded into an outer shape along the inner surface shape of the cavity, and then the molded product is taken out from the cavity in an unvulcanized state,
An injection step of injecting an unvulcanized rubber material in a fluid state in the cavity;
And a cooling step of cooling the rubber material injected into the cavity in the cavity by a cooling means.

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