JPH066312B2 - Molding method for cap with sealing material and molding apparatus used therefor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of molding a cap with a sealing material and a molding apparatus used for the method.

(Prior Art) A cap with a sealing material is often used in which a sealing material for sealing is attached to an inner end surface of a cap body having a male screw portion formed on an inner peripheral surface. When such a cap with a sealing material is conventionally made of resin, the cap body and the sealing material are separately resin-molded, and the sealing material is attached to the inner end surface of the cap body by an adhesive.

(Problems to be Solved by the Invention) However, the above-described conventional method for manufacturing a cap with a sealing material has the following problems.

The molding process of the cap body and the sealing material is separate, and the step of attaching the sealing material is added, so the workability is extremely poor.
In addition, there is a problem that it is difficult to insert the sealing material because the male thread portion is formed on the inner wall surface of the cap body.

Therefore, it is an object of the present invention to provide a method for molding a cap with a sealing material, which can mold the cap body and the sealing material in one step, and a molding apparatus used for the method.

(Means for Solving the Problems) In order to solve the above problems, the present invention has the following configuration.

That is, the present invention is a molding die in which a cap body forming cavity forming the cap body is recessed when molding a cap with a sealing material in which a sealing material is provided on the inner bottom portion of the cap body, Provided in the molding die,
A first resin passage, which is connected to the cap body forming cavity and through which a molten resin for molding the cap body passes, and a male screw portion are formed on an outer peripheral side surface, and the cap body is rotatable about an axis line. A core having a distal end capable of advancing and retreating in the axial direction in the forming cavity, a driving means for rotating and advancing and retracting the core in the cap body forming cavity, and provided in the core, After the molten resin is injected into the cavity for forming the cap body through the first resin passage to mold the cap body, and when the core is retracted by a predetermined amount while rotating the core by the driving means, the inside of the cap body A molding apparatus comprising: a second resin passage for injecting a resin for molding a sealing material into a cavity for forming a sealing material, which is formed between a wall surface and an outer wall surface of the core. Of the threads forming the male thread formed at the tip of the core to be inserted into the cavity for forming the main body, the thread crest on the tip side of the core is formed higher than the thread crest on the following side. Using the cap forming device,
After positioning the core tip portion at a predetermined position in the cap body molding cavity, a molten resin is injected into the cavity body forming cavity to form a cap body, and then the core is rotated to The internal thread portion formed on the inner peripheral surface of the cap body by the screw thread on the subsequent side is retracted by a predetermined amount while being threaded by the screw thread on the tip side of the core, and is moved between the inner wall surface of the cap body and the outer wall surface of the core. In the method for forming a cap with a sealing material, a cavity for forming a sealing material is formed in, and then a resin for molding a sealing material is injected into the cavity for forming a sealing material.

In addition, the present invention provides a molding die having a cavity for forming a cap body, and a molten resin which is provided in the molding die and which is connected to the cavity for forming the cap body and which molds the cap body. A first resin path, and a core provided with a male screw portion on the outer peripheral side surface, rotatable about an axis and provided with a distal end movable in the axial direction in the cap body forming cavity. Driving means for rotating and advancing / retreating the core in the cap body forming cavity; and a molten resin provided in the core and passing through a first resin passage in the cap body forming cavity. After injecting and molding the cap body, when retracting a predetermined amount while rotating the core by the driving means,
A molding apparatus comprising: a second resin passage for injecting a resin for molding a sealing material into a cavity for forming a sealing material, which is formed between an inner wall surface of the cap body and an outer wall surface of the core. Among the threads forming the male screw formed at the tip of the core inserted into the forming cavity, the top of the thread on the tip of the core is formed higher than the top of the thread on the following side. It is also a molding device for a cap with a sealing material.

(Operation) According to the present invention, first, after molding the cap body, the sealing material is molded in the seal molding cavity formed by retracting the core, so that the cap with the sealing material can be molded in the molding process. Moreover, when molding the sealing material, the female screw portion on the inner peripheral surface of the cap body does not become an obstacle at all.

Moreover, in the present invention, when forming the cavity for molding the sealing material, the female screw portion formed on the inner peripheral surface of the cap body by the screw on the subsequent side following the screw on the tip side of the core is Is formed on the male screw part of the core and the inner peripheral surface of the cap body in order to retract the core by a predetermined amount while threading with the screw on the tip side of the core, which has a higher screw crest than the screw crest. The gap between the female screw and the female screw can be zero.

As a result, it is possible to prevent burrs from being generated due to the gap between the male screw portion and the female screw portion, and it is possible to mold the burr-free cap body with a sealing material.

(Examples) Hereinafter, preferred examples of the present invention will be described in detail with reference to the accompanying drawings.

First, the configuration of a molding apparatus suitable for carrying out the method for molding a cap with a sealing material according to the present invention will be described with reference to FIG. FIG. 1 shows a front sectional view of the molding apparatus.

Numerals 10 and 12 are molding dies, and a cavity 14 for cap body molding is provided in the mold 10 in a recessed manner. On the other hand, the mold 12 is provided with a first resin path 16. The first resin passage 16 communicates with the cavity 14 for molding the cap body when the molds 10 and 12 are closed.
The first resin passage 16 is a passage for sending the molten resin for molding the cap body injected from the first nozzle 18 to the cavity 14 for molding the cap body.

Reference numeral 20 denotes a core, and a male screw portion 22 is formed on the outer circumference. The core 20 is screwed to the female screw portion 24 of the die 12, and the core 20 can be moved back and forth in the axial direction by rotating the core 20 about its axis. As a result, the tip of the core 20 can be inserted into the cavity 14 for molding the cap body when the molds 10 and 12 are closed. Reference numeral 26 is an output shaft 2 which is a motor as a driving means.
A toothed pulley 30 is provided at the tip of the eight wheels. A toothed belt 32 is stretched over the toothed pulley 30. The toothed belt 32 includes the toothed pulley 30 of the motor 26 and the core 2
No. 0 is provided on the outer periphery of the rear end portion of the core 20, and meshes and bridges between gear portions 34 having teeth formed so as to extend in the axial direction of the core 20. Therefore, when the motor 26 rotates, the core 20
The rotational force of the motor 26 is transmitted to the core 20, and the core 20 rotates about the axis and moves in the axis direction. The motor 26 is fixed to the mold 12 as shown.

Reference numeral 36 is a second resin passage, which is provided through the core 20 along the axis of the core 20. The second resin passage 36 is a passage for sending the resin for molding the seal material injected from the second nozzle 38 to the cavity for molding the seal material (described later).
A ball valve 40 for check is arranged at the tip of the second resin passage 36, and when the resin is injected from the second nozzle 38, the pressure thereof opens the tip of the second resin passage 36. When the molten resin for molding the cap body is injected from the first resin passage 16 into the cavity 14 for molding the cap body, the pressure closes the tip of the second resin passage 36 to mold the cap body. The resin is prevented from entering the second resin passage 36.

Next, the molding method according to the present invention will be described together with the operation of the molding apparatus configured as described above.

First, as shown in FIG. 1, the core 20 is positioned at a predetermined position in order to mold the cap body 42.

Then, the first nozzle 18 is connected to the first resin passage 16,
Molten resin for molding the cap body 42 is injected from the first nozzle 18. The molten resin injected from the first nozzle 18 is sent to and filled in the cavity 14 for forming the cap body. At this time, the ball valve 40 prevents the molten resin for molding the cap body 42 from entering the second resin passage 36.
When the resin in the cap molding cavitate 14 is solidified, the molding of the cap body 42 having the female screw portion on the inner peripheral surface is completed.

Next, as shown in FIG. 2, the first nozzle 18 is retracted, and the motor 26 is driven to retract the core 20 to the right by a predetermined amount A while rotating it. Then, a space is created between the inner wall surface of the cap body 42 and the outer wall surface of the tip of the core 20. This is the sealing material molding cavity 44.
Then, the second nozzle 38 is connected to the second resin passage 36, and the resin for molding the sealing material 46 is injected from the second nozzle 38. The resin injected from the second nozzle 38 pushes the ball valve 40 to open the tip of the second resin passage 36 and fill the cavity 44 for molding the sealing material. When the resin in the sealing material molding cavity 44 is solidified, the molding of the sealing material 46 is completed, and the cap with sealing material is completed.

When the cap with the sealing material is completed, the first and second nozzles 18 and 38 are sufficiently retracted to the right, and then the motor 26 is driven to further retract the core 20 to the right while rotating it. When the core 20 separates from the cap body 42, the motor 26 is stopped, and the molds 10 and 12 are opened to take out the cap with the sealing material.

In this embodiment, as shown in FIGS. 3 and 4, in order to shape the burr-free sealing material 46 when molding the sealing material 46 using a material that easily flows such as silicone rubber, Of the threads forming the male thread 22 formed on the outer peripheral side surface of the core 20, only the three threads on the tip side of the core are formed in a pointed shape, and the tops of the remaining threads are formed flat.

Therefore, the tops of the three threads on the tip side of the core can be higher than the tops of the following threads.

When forming a cap with a sealing material using such a core 20, after molding the cap main body 42 as shown in FIG. 3, the core 20 is retracted by one and a half rotations as shown in FIG. When forming the material molding cavity, the female screw portion 24 formed on the inner peripheral surface of the cap main body 42 by the screw on the subsequent side having a flat top portion is used to form the core tip with the top portion formed into a pointed tip. Because it is threaded by the side screw,
The gap between the pointed screw thread and the female screw portion formed on the inner peripheral surface of the cap body can be made zero.

Therefore, even if a material such as silicone rubber that flows in even with a gap of only about 5 microns is injected from the second resin passage 36 into the cavity for molding the sealing material, the male screw portion 22 of the core 20 and the cap body are not separated. Since the gap between the female screw portion formed on the inner peripheral surface is zero, it is possible to form a cap with a sealing material having a beautiful appearance without burrs.

(Effect of the Invention) By using the molding method of the cap with a sealing material and the molding device according to the present invention, not only the cap body and the sealing material can be shaped in one molding step, but also the sealing material can be attached. It is possible to reduce the number of manufacturing steps for the cap with a sealing material and to significantly reduce the manufacturing time. As a result, workability is improved and production cost can be reduced. Further, since the sealing material is molded in the cap body, even if the female screw portion is formed on the inner peripheral surface of the cap body, it does not cause any trouble. Further, if the cavity for molding the sealing material is deepened, the sealing material can also be molded by engaging with the female screw portion of the inner peripheral surface of the cap body, so that the sealing material will not fall off even if it is not adhered to the cap body. Moreover, even if the sealing material is molded using a material that easily flows, such as silicone rubber, a cap with a sealing material that has a beautiful appearance without burrs can be molded.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing a state during molding of a cap body of a molding apparatus suitable for carrying out the method for molding a cap with a sealing material according to the present invention, and FIG. Front sectional view showing the state, FIG.
FIG. 4 is a partially enlarged sectional view of FIG. 4, and FIG. 4 is a partially enlarged sectional view of FIG. 10, 12 ... Mold, 14 ... Cap body molding cavity, 16 ... First resin passage, 20 ... Core, 22 ... Male screw portion, 26 ... Motor, 36 ... Second resin passage, 42 ... Cap body, 44 ... Cavity for molding sealant, 46 ... Sealant.

Claims (2)

[Claims] 1. A molding die in which a cap body forming cavity forming the cap body is recessed when a cap with a sealing material having a sealing material provided on the inner bottom of the cap body is molded, A first resin path, which is provided in the molding die and is connected to the cap body forming cavity and through which the molten resin for molding the cap body passes, and a male screw portion are formed on the outer peripheral side surface, and rotate around the axis. A core that is movably provided and has a distal end that can advance and retreat in the axial direction in the cap body forming cavity; and a drive unit that rotates and advances and retracts the core in the cap body forming cavity. After the molten resin is injected into the cavity for cap body formation provided in the core through the first resin passage to mold the cap body, the core is moved by the driving means. A second resin path for injecting a resin for molding the sealing material into a sealing material forming cavity formed between the inner wall surface of the cap body and the outer wall surface of the core when retracted by a predetermined amount while rolling; Among the threads forming the male screw part formed in the core tip portion inserted into the cap body forming cavity, the screw tip on the tip side of the core is the screw on the trailing side. Using a molding device for a cap with a sealing material formed higher than the top of the mountain, after positioning the tip of the core at a predetermined position in the cavity for molding the cap body, injecting molten resin into the cavity for forming the cavity body Then, the cap body is molded, and then the core is rotated so that the female screw portion formed on the inner peripheral surface of the cap body by the screw thread on the subsequent side is not threaded by the screw thread on the tip end side of the core. But A certain amount from the
A sealing material forming cavity is formed between the inner wall surface of the cap body and the outer wall surface of the core, and then a sealing material forming resin is injected into the sealing material forming cavity. Molding method. 2. A molding die in which a cavity for forming a cap body is provided, and a molten resin which is provided in the molding die and which is connected to the cavity for forming a cap body and which molds the cap body, passes therethrough. A first resin path; and a core provided with a male screw portion on an outer peripheral side surface, rotatable about an axis and provided with a tip portion capable of advancing and retracting in the axial direction inside the cap body forming cavity. Driving means for rotating and advancing and retracting the core in the cavity for forming the cap body, and molten resin injected into the cavity for forming the cap body through the first resin passage provided in the core. After molding the cap body, the sealing material forming cavities formed between the inner wall surface of the cap body and the outer wall surface of the core when the core is retracted by a predetermined amount while being rotated by the driving means. A molding device comprising a second resin passage for injecting a resin for molding a sealing material into a tee, wherein a male screw portion formed at a tip end portion of a core inserted into the cavity for forming the cap body is provided. A molding apparatus for a cap with a sealing material, wherein among the constituent threads, the thread crest on the tip side of the core is formed higher than the thread crest on the subsequent side.