JPH06328590A - Molding of belt by using liquid molding material - Google Patents

Abstract

PURPOSE:To achieve labor-saving due to the omission of a plug closing process and the automation of the molding of a belt while surely achieving the filling of a mold with a liquid molding material. CONSTITUTION:A mold 3 equipped with a cylindrical molding space 8, the discharge port 14 communicating with the top part of the molding space and the injection port 13 communicating with the bottom part of the molding space is used. In a preparation process, the downstream end 15a of an extension pipe 15 is connected to the injection port 13 and the upstream end 15b thereof is connected to through-hole 18 and the height of the upper end opening of the through-hole 18 at an injection start point is made the same as that of the upper end opening of the discharge port 14 at an injection end point. In a filling process, a liquid molding material is injected into the molding space from the upstream end of the extension pipe and the injection of the liquid molding material is continued up to the point of time when the liquid molding material entering the molding space through the injection port 13 rises in the molding space to reach the discharge hole 14 is stopped. By this constitution, both liquid surfaces of the liquid molding material on the side of the discharge hole 14 and the side of the extension pipe are mutually held to the same horizontal surface. A curing process is performed in such a state that the extension pipe 15 is connected to the mold and, after the completion of the curing process, the extesion pipe 15 is cut off from the mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a belt used for molding a transmission belt such as a transmission ribbed belt or a belt with a rear projection by using a liquid molding material such as thermosetting polyurethane.

[0002]

2. Description of the Related Art Generally, a belt is molded from a liquid molding material of this type by using a mold 3a having an injection hole 1 and a discharge hole 2 formed on the upper portion thereof as shown in FIG. . The mold 3 includes a base body 4 and the base body 4
A cylindrical inner mold 5 arranged on the upper mold, an outer mold 6 arranged by being fitted around the inner mold 5, and a lid for closing the upper surfaces of both molds 5, 6. A cylindrical molding space 8 extending in the vertical direction is defined between the outer peripheral surface of the inner mold 5 and the inner peripheral surface of the outer mold 6 by the body 7. In addition, the injection hole 1 and the discharge hole 2 that communicate with the molding space 8 are formed in the lid body 7 so as to penetrate at positions separated from each other. The molding of the belt basically includes a filling step of filling the mold 3a with the liquid molding material and a curing step of hardening the liquid molding material after the filling. In the filling step, the injection (casting) of the liquid molding material is started from the injection hole 1 and the injection is ended when the injected liquid molding material overflows from the discharge hole 2 and overflows. The molding space 8 is filled with the liquid molding material. Next, in the curing step, the filled mold 3a is placed in a high temperature furnace and heated in the high temperature furnace to cure the liquid molding material in the molding space 8. Then, the belt molded product is obtained by releasing from the mold 3a.
In the case of this molding method, since the liquid molding material is injected from the top to the bottom in the filling step, for example, the concave-convex shaped molding portion (see FIG. 3) 9 for forming the ribs or protrusions of the belt is provided outside When formed on the inner peripheral surface of the mold 6, air is sealed and remains inside the recess 9a of the molding portion 9 when the liquid molding material 10 flows down, which may cause filling failure. There is.

On the other hand, conventionally, as a belt forming method having such a forming portion 9, a method using a mold 3b as shown in FIG. 4 has been proposed (for example, Japanese Patent Publication No. 47-32824). See the bulletin). The die 3b in this method is composed of a base body 4, an inner die 5, an outer die 11 and a lid 12 as in the die 3a, and the injection hole 13 is formed in the outer die 11. Discharge holes 14 are formed in the lower side surface so as to penetrate the lid 12. Then, the liquid molding material 10 is injected from the injection hole 13 while sucking from the discharge hole 14, and the injected liquid molding material 10 is gradually raised in the molding space 8 as shown in FIG. By discharging the air from the mold 14, all the air in the molding space 8 is discharged from the discharge hole 14 without leaving the air in the recess 9a of the molding portion 9.

[0004]

By the way, the mold 3 is used.
In the conventional belt molding method using b, since the injection hole 13 is formed in the lower side surface of the outer mold 12, after the liquid molding material is filled through the injection hole 13, the filled liquid molding material is It is necessary to close the injection hole 13 so that it does not flow out. That is, after the filling step and before the hardening step, a plugging step for liquid-tightly closing the injection hole 13 is required.

However, in this plugging step, after the filling is completed, the pumping pipe for the liquid molding material connected to the injection hole 13 is removed and the injection hole 13 is closed at the same time, so that the work is difficult. Accompanied by. Then, if the timing of the capping operation is shifted, the liquid molding material flows out from the injection hole 13, or if the capping is not securely closed, the liquid molding material leaks. If such an outflow or leakage occurs, not only may the contamination of the periphery of the mold be caused, but also the liquid level of the liquid molding material in the molding space 8 may be lowered and the filling amount may be insufficient. Moreover, such a capping process is complicated and must rely on manual work, which is an obstacle to promoting automation of belt manufacturing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to ensure filling of a liquid molding material into a mold and to save labor by omitting a capping step. The goal is to promote automation and automation.

[0007]

In order to achieve the above object, the present invention according to claim 1 provides a cylindrical molding space, a discharge hole communicating with the top of this molding space and opening upward, and the above molding. Using a mold with an injection hole communicating with the bottom of the space,
A filling step of filling the liquid molding material into the molding space,
The object of the present invention is to include a curing step of curing the filled liquid molding material. In this thing, a preparation process is performed first and a filling process is performed after that. In this preparatory step, the downstream end of the extension pipe is detachably connected to the injection hole, while the upstream end of the extension pipe is positioned at substantially the same height as the discharge hole, and the extension pipe is attached to the mold. Install.
Next, as the filling step, filling is started by injecting a liquid molding material from the upstream end of the injection pipe, and the liquid molding material that has entered the molding space through the injection hole rises in the molding space. The injection is continuously stopped at least until the discharge hole is reached. Then, the liquid level of the liquid molding material on the discharge hole side and the liquid level of the liquid molding material on the extension tube side are kept substantially on the same horizontal plane, and the filling is completed.

According to a second aspect of the invention, in the invention of the first aspect, the curing step is performed in a state where the extension pipe is connected to the mold. Then, after the curing step is completed, the injection pipe is separated from the mold.

[0009]

With the above construction, in the invention according to claim 1,
At the completion of the filling step, the liquid level of the liquid molding material at the upstream end of the extension pipe, which is the start point of the injection, and the liquid level of the liquid molding material at the discharge hole, which is the end point, were maintained on substantially the same horizontal plane. As a result, the liquid molding material in the molding space is kept stationary regardless of the presence or absence of the action of the injection pressure, which makes it possible to omit the plugging step when the injection is stopped, which is required in the conventional belt molding method. It will be possible. For this reason, it is possible to reliably prevent the occurrence of adverse effects in the conventional method, such as defective filling in the molding space due to the execution of the capping step.
Moreover, in the filling step, it is only necessary to stop the injection of the liquid molding material when the predetermined state is reached, which contributes to the promotion of automation of the belt molding together with the omission of the capping step.

In addition, in the present invention in which the capping step is omitted, the liquid molding material is introduced from the bottom of the molding space through the extension pipe, and the liquid molding material rises to the discharge hole at the top of the molding space. Even if the molding space has an uneven molding portion, air such as bubbles does not remain, and the liquid molding material is reliably filled into the molding space.

According to the second aspect of the invention, in addition to the function of the first aspect of the invention, the curing step is performed in a state where the extension pipe is connected, and the extension tube is disconnected after the curing step is completed. Therefore, it becomes possible to continuously perform the filling step and the subsequent curing step.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a molding die 3 and an extension pipe 15 used in a belt molding method according to an embodiment of the present invention. The molding die 3 includes a base body 4 that is fixed on a horizontal plate (not shown), and a cylindrical inner die 5 that is positionally fixed on the upper surface of the base body 4 with the cylinder axis X directed vertically. A cylindrical outer mold 16 fitted on the upper surface of the base body 4 while being coaxially fitted around the outer periphery of the inner mold 5, and upper surfaces of the inner mold 5 and the outer mold 16. And a lid body 17 that is fitted to each of them and closes the upper surfaces of the both 5, 16. Then, between the outer peripheral surface of the inner mold 5 and the inner peripheral surface of the outer mold 16, a cylindrical molding space 8 which is surrounded by the lid body 17 and the base body 4 and extends in the vertical direction is defined. Is made. On the inner peripheral surface of the outer mold 16, which is on the outer peripheral side of the molding space 8, a concave-convex shaped portion 9 (see FIG. 3) is formed, and a belt having ribs corresponding to the shaped portion 9 is formed. The molded product is designed to be molded.

An injection hole 13 communicating with the bottom of the molding space 8 is formed in the side surface of the lower end portion of one side (the left side in FIG. 1) of the outer die 16 sandwiching the cylinder axis X, A connecting portion 16a is formed on the outer peripheral surface of the outer die 16 at a position corresponding to the injection hole 13 so as to project outward and connect the downstream end of the extension pipe 15.

At a position on the other side (right side in FIG. 1) of the lid body 17 that sandwiches the cylinder axis X, a discharge hole 14 that communicates with the top of the molding space 8 and opens upward is formed. Also,
The lid 17 has an edge portion 17 on the same side as the connecting portion 16a.
a is projected horizontally to the left in FIG. 1, and a through hole 1 is formed in this edge portion 17a to vertically penetrate the lid body 17.
8 is formed. A connecting portion 17b for connecting the upstream end of the extension pipe 15 is formed on the lower surface of the end edge portion 17a at a position corresponding to the through hole 18 so as to project downward. Here, the through hole 18 and the discharge hole 14
Are positioned such that their upper openings are located on the same horizontal plane.

The extension pipe 15 is composed of, for example, a flexible hose made of heat-resistant resin. The downstream end 15a is connected to the connecting portion 16a of the outer mold 16, and the upstream end 15b is connected to the connecting portion 17b of the lid 17. Each is detachably connected.

Next, the mold 3 and the extension tube 1 having the above-mentioned structure.
A belt forming method using No. 5 will be described.

The belt molding method is basically composed of a preparation step, a filling step, and a curing step. First, in the preparation step, the assembling of the molding die 3 and the connection of the extension pipe 15 to the molding die 3 are performed. The assembling of the molding die 3 is carried out by fitting the inner die 5 and the outer die 16 to a predetermined position on the upper surface of the base body 4 by fitting or the like. Are joined by fitting. Then, the downstream end 15a of the extension pipe 15 is connected to the connecting portion 16a of the outer mold 16, and the upstream end 15b is connected to the connecting portion 17b of the lid 17. This completes the preparation process.

In the filling step, a liquid molding material such as thermosetting polyurethane is injected from the upper end opening of the through hole 18. As a result, the liquid molding material enters the bottom portion of the molding space 8 through the extension tube 15 and the injection hole 13, and by continuing the injection, the liquid level of the liquid molding material in the molding space 8 gradually rises. Then, when the liquid surface of the liquid molding material in the molding space 8 enters the discharge hole 14 and reaches the upper end opening position of the discharge hole 14, the injection is stopped. As a result, the liquid level of the liquid molding material in the through hole 18 on the starting point side of the injection and the liquid level of the liquid molding material in the discharge hole 14 on the ending point side of the injection are located on substantially the same horizontal plane. The filling step is completed in this state. As an example of the liquid molding material, 100 parts by weight of Hyprene L-100 (trade name) at 80 ° C.
12.7 parts by weight of 3.3'-dichloro-4.4'-diamino-diphenylmethane, which has been kept at 0 ° C., is weighed in each, and a mixture thereof is included.

Next, in the curing step, with the extension pipe 15 and the molding die 3 integrally connected, both 15 and 3 are placed in a high temperature furnace (not shown) and heated at a predetermined temperature for a predetermined time. As a result, the liquid molding material in the molding space 8 and the extension tube 15 is cured, and the curing step is completed.

After cooling the molding die 3 and the like, the extension pipe 15 is detached from the connecting portions 16a and 17b,
The cured belt molding is released from the molding die 3.
Since the hardened molding material is clogged inside the removed extension pipe 15, this is discarded and another new extension pipe is used for the next belt molding. The belt molded product is cut into a predetermined width to form a final product belt.

In the case of such a belt molding method, in the filling step, the liquid molding material is introduced from the bottom of the molding space 8 so that the liquid molding material gradually rises in the molding space 8. Even if the molding space 8 has a concave-convex shaped molding portion 9, it is possible to reliably fill the liquid molding material without leaving air in the molding portion 9.

At the completion of the filling step,
Since the liquid surface of the liquid molding material in the through hole 18 which is the starting point of the injection and the liquid surface of the liquid molding material in the discharge hole 14 which is the ending point of the injection are kept on substantially the same horizontal plane,
The liquid molding material does not move within the molding space 8 regardless of the effect of the injection pressure. Therefore, the plugging step at the time of stopping the injection, which is required in the conventional belt molding method, can be omitted in this embodiment, and the occurrence of adverse effects such as filling failure in the molding space 8 due to the execution of the plugging step is surely performed. Can be prevented.

In addition, in the filling step, the injection of the liquid molding material only needs to be stopped when the predetermined state is reached, and since the hardening step can be performed continuously with the filling step, the capping step is performed. Combined with the omission of, the automation of belt molding can be promoted.

The present invention is not limited to the above embodiment, but includes various other modifications. That is, in the above embodiment, the case where the molding die 3 is arranged in the up-down direction and the filling step is performed is shown. However, the present invention is not limited to this, and the filling step may be performed with the molding die lying down.

In the above embodiment, the injection hole 13 is formed in the outer mold 16.
Although the molding die 3 formed on the side surface of the lower end of the base body 4 is used, the present invention is not limited to this, and for example, a base body 4 provided by penetrating the injection hole may be used.

In the above embodiment, when the injection in the filling step is stopped, the liquid surface of the liquid molding material from the molding space 8 is discharged from the discharge hole
Although it is the time when the upper end opening of 4 is reached, the present invention is not limited to this, and it is sufficient that both liquid surfaces of the liquid molding material on the starting point side and the end point side of the injection are kept in the same horizontal surface in the final state of the filling process, For example, the injection may be stopped when the liquid molding material slightly overflows from the discharge hole 14.

In the above embodiment, the lid 17 has a connecting portion 17b.
Is integrally formed to connect the upstream end 15b of the extension pipe 15 to the connecting portion 17b, but the present invention is not limited to this. For example, a lid is provided with a holding portion for the upstream end 15b, and the upstream end 15b is The upper end opening may be positioned at the same height as the upper end opening of the discharge hole 14.

In the above embodiment, the extension pipe 15 is made of heat-resistant resin, but may be made of metal, for example.

Further, in the above embodiment, the case where the thermosetting polyurethane is used as the liquid molding material and the curing step is carried out by heating in the high temperature furnace is not limited to this. For example, the curing step is selected by selecting the liquid molding material. It is also possible to employ a method of curing without heating in a high temperature furnace.

[0031]

As described above, according to the method of molding a belt by the liquid molding material of the first aspect of the invention, at the completion of the filling step, the liquid molding at the upstream end of the extension pipe, which is the starting point of the injection, is performed. Since the liquid surface of the material and the liquid surface of the liquid molding material at the discharge hole, which is the end point, are kept on substantially the same horizontal plane, regardless of the presence or absence of the action of the injection pressure, The liquid molding material can be kept stationary, and the plugging step at the time of stopping injection, which is required in the conventional belt molding method, can be omitted. As a result, it is possible to reliably prevent the occurrence of adverse effects in the conventional method such as defective filling in the molding space due to the execution of the capping step. Moreover, in the filling step, the injection of the liquid molding material only needs to be stopped at the time when the predetermined state is reached, so that the automation of the belt molding can be promoted in combination with the omission of the capping step. .

In addition, in the present invention in which the capping step is omitted, the liquid molding material is introduced from the bottom of the molding space through the extension pipe to raise the liquid molding material to the discharge hole at the top of the molding space. Therefore, even if the molding space has an uneven molding portion, it is possible to reliably fill the liquid molding material without leaving air such as bubbles.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a curing step is performed in a state where the extension pipe is connected, and the extension tube is separated after the curing step is completed. Therefore, the filling step and the subsequent curing step can be performed easily and quickly in succession.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molding die and an extension pipe used in an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a molding die used in a conventional belt molding method.

FIG. 3 is a partially enlarged view of a molding space in a filling process with the molding die in FIG.

FIG. 4 is a cross-sectional view of a molding die used in a conventional belt molding method different from that in FIG.

5 is a partially enlarged view of a molding space in a filling step with the molding die of FIG.

[Explanation of symbols]

 3 Molding die 8 Molding space 13 Injection hole 14 Discharge hole 15 Extension pipe 15a Downstream end of extension pipe 15b Upstream end of extension pipe

Claims (2)

[Claims] 1. A molding space including a cylindrical molding space, a discharge hole that communicates with a top portion of the molding space and opens upward, and an injection hole that communicates with a bottom portion of the molding space. In a belt molding method using a liquid molding material, which comprises a filling step of filling the inside with a liquid molding material and a curing step of curing the filled liquid molding material, the downstream end of the extension pipe is While detachably connecting to the injection hole, the upstream end of the extension pipe is positioned at substantially the same height as the discharge hole, and a preparatory step of attaching the extension pipe to the mold is performed. The filling step is started by injecting the liquid molding material from the upstream end of the extension pipe, and the liquid molding material that has entered the molding space through the injection hole rises in the molding space and reaches at least the discharge hole. Time to do Then, the injection is stopped continuously, and the liquid surface of the liquid molding material on the discharge hole side and the liquid surface of the liquid molding material on the extension tube side are kept on substantially the same horizontal plane, and the filling step is performed. A method for molding a belt using a liquid molding material, characterized by completing the method. 2. The belt molding method according to claim 1, wherein the curing step is performed in a state where the extension tube is connected to the mold, and after the curing step, the extension tube is separated from the mold. .