JPH044125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold in which a plurality of liquid flow passages for cooling or heating a cavity are arranged in a row.

For example, in plastic molds, in order to shorten the molding cycle, so-called water holes are formed in the mold for passing cooling water or hot oil for heating. In the case where the cavity is formed by electroforming, for example, a copper or stainless steel pipe is closely placed along the outer surface of the cavity, and cooling water or hot oil for heating is passed through the pipe. There is. Such a structure has the advantage that even if the shape of the molded product is complex, the pipe is located close to the inner surface of the cavity, that is, near the outer surface of the molded product, allowing for good cooling and heating.

By the way, if the mold is large, multiple pipes are arranged in parallel along the outer surface of the cavity, but in this case, a hollow cylindrical liquid distribution pipe is provided where the inlet ends of each pipe communicate at approximately right angles. A discharge pipe from a pump that pumps cooling water or hot oil is connected to one end of the liquid distribution pipe. However, the cooling water or hot oil discharged from the discharge pipe is discharged from one end of the liquid distribution pipe and collides with the other end of the liquid distribution pipe with force, so the pressure distribution inside the liquid distribution pipe varies from one end to the other end of the liquid distribution pipe. The flow rate of cooling water or hot oil flowing through each pipe will be extremely unbalanced if left as is, making it extremely difficult to uniformly heat or cool the cavity. It is. Therefore, in the past, a valve for adjusting the flow rate was provided near the inlet end of each pipe, and the opening degree of each valve was adjusted so that the flow rate of cooling water or hot oil flowing through each pipe was constant. However, for example, molds for PVC slush molds have a high cure temperature of 240 to 260°C, so very expensive gun metal valves with excellent heat resistance must be used. The disadvantage is that the cost of the mold increases significantly, and
Since the opening degree of each valve must be adjusted,
The disadvantage is that it is difficult to handle.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to equalize the flow rate of liquid flowing through a plurality of liquid flow paths with an extremely simple configuration, eliminate the need for expensive valves, and reduce the cost. To provide a mold that can be manufactured and easily handled.

An embodiment in which the present invention is applied to a plastic mold will be described below with reference to the drawings. That is, a plastic mold usually consists of a pair of upper and lower molds that are divided into upper and lower parts along a parting line, and the lower mold 1 will be explained below. 2
is a cavity manufactured by electroforming method,
This is done by electrodepositing, for example, nickel to a predetermined thickness on the surface of a matrix (not shown) that is made of a conductive or non-conductive material and then cutting out the matrix after electrodeposition. It is formed by forming a molding recess 3 having a concavo-convex shape opposite to that of the mold. Reference numeral 4 denotes a liquid flow path consisting of copper pipes or stainless steel pipes that are arranged in parallel in contact with the outer surface of the cavity 2, and each of these has an outer diameter of about 7 to 10 mm and is connected to the cavity 2 by high-temperature soldering or welding. It is attached firmly. 5 is a hollow cylindrical or square cylindrical liquid distribution chamber fixed to the outer surface of the cavity 2 by welding or the like, and each inlet end of the liquid flow passage 4 is connected to the liquid distribution chamber 5.
The liquid distribution chamber 5 communicates approximately perpendicularly with the circumferential side thereof, and both ends of the liquid distribution chamber 5 in the longitudinal direction are closed by end plates 6 and 7. Reference numeral 8 denotes a liquid inflow pipe having a diameter approximately 1/2 of the inner diameter of the liquid distribution chamber 5 and open at both ends. It projects a predetermined length d with a space around it, and a required number of circular openings 9 of predetermined dimensions communicating with the liquid distribution chamber 5 are bored on the outer periphery of the liquid inflow pipe 8. has been done. Reference numeral 10 designates a cylindrical or square cylindrical liquid collecting chamber which is also fixed to the outer surface of the cavity 2 by welding or the like, and each outlet end of the liquid flow passage 4 is approximately perpendicular to the circumferential surface of the liquid collecting chamber 10. One end of the liquid collecting chamber 10 is closed by an end plate 11, and an end plate 12 having an outlet body 12a is attached to the other end. A discharge pipe from a pump (not shown) that pumps hot oil or cooling oil or hot water or cooling water is connected to the end of the liquid inflow pipe 8, and the liquid collection chamber 1 is connected to the outlet body 12a.
A return pipe is connected to return the hot oil or cooling oil, hot water or cooling water collected in the tank to the tank or the like. The cavity 2 described above is attached to a formwork (not shown), and the outer surface of the cavity 2 is filled with a filler such as epoxy resin when reinforcement is required, and when heat retention is required. is filled with insulation material. Further, an upper mold (not shown) that is paired with the lower mold 1 is manufactured in the same manner as the lower mold 1.

Next, the operation of the above configuration will be explained. When a pump (not shown) is driven to supply hot oil, for example, to the liquid inflow pipe 8 through the discharge pipe, the hot oil flows into the liquid distribution chamber 5 through the tip of the liquid inflow pipe 8 and the opening 9. The liquid flows from the liquid distribution chamber 5 through each liquid flow path 4 to the liquid collection chamber 10 and the outlet body 12a in this order, and is returned to the tank or the like. Then, the thermal energy of the hot oil flowing through each liquid flow path 4 is transferred to the cavity 2.
is applied to heat the cavity 2.

By the way, according to the inventor's experiments, when the pressure of the hot oil flowing into the liquid inflow pipe 8 is constant, the liquid distribution chamber 5
By adjusting the protruding length d of the tip of the liquid inflow pipe 8 relative to the liquid inflow pipe 8, the pressure distribution in the inner peripheral portion of the liquid distribution chamber 5 excluding the end plates 6 and 7 becomes approximately uniform, and the liquid is supplied to each liquid flow passage 4. It was found that the amounts of hot oil were all approximately equal. This experiment was conducted by attaching the liquid flow passage 4 and the liquid distribution chamber 5 to the cavity 2 and before installing the liquid assembly 10, water was supplied to the liquid inflow pipe 8 at the same discharge pressure as during molding. Visually check the amount of water flowing out from each outlet end or measure it with a flow meter.
The protruding length d of the tip of the liquid inflow pipe 8 is set so that each has a substantially equal outflow amount, and after setting, the liquid inflow pipe 8 is fixed to the end plate 7 and the liquid collection chamber 1
0 is communicated with the outlet end of each liquid flow path 4. In this case, in addition to fixing the liquid inflow pipe 8 after setting the appropriate protrusion length d by experiment as described above, if the appropriate protrusion length d is known in advance, the liquid inflow pipe 8 can be fixed in advance. You can also leave it as is. Although the openings 9 may be provided as necessary, the presence of the openings 9 can further equalize the amount of liquid flowing through each liquid flow path 4.

As a result, the amount of liquid (hot oil or cooling oil, hot water or cooling water) flowing through each liquid flow path 4 becomes uniform, so that the entire cavity 2 is uniformly heated or cooled.

According to the above configuration, the liquid inflow pipe 8 is connected to each liquid flow path 4.
The simple structure of projecting a predetermined length into the liquid distribution chamber 5 with a space surrounding the distal end of the liquid distributing chamber 5 eliminates the need for expensive valves with high heat resistance. This eliminates the need for mold manufacturing costs, and also eliminates the need for troublesome valve opening adjustments.

Note that if the outflow pipe is attached to the liquid collection chamber 10 so that its tip protrudes a predetermined length into the liquid collection chamber 10 in the same manner as the liquid inflow pipe 8, the pressure distribution within the liquid collection chamber 10 will be uniform. In this way, the amount of liquid flowing through each liquid flow path 4 can be made more uniform, but this may be done as necessary.

As is clear from the above description, the present invention can equalize the amount of liquid flowing through a plurality of liquid flow passages with an extremely simple structure, eliminates the need for expensive valves, can be manufactured at low cost, and is easy to handle. We can provide molds that can

[Brief explanation of drawings]

The drawings show an embodiment in which the present invention is applied to a plastic mold, and FIG. 1 is a longitudinal sectional view;
FIG. 2 is a partially cutaway bottom view. In the drawings, 1 is a lower mold, 2 is a cavity, 3 is a molding recess, 4 is a liquid flow passage, 5 is a liquid distribution chamber, 8 is a liquid inflow pipe, and 10 is a liquid collection chamber.

Claims (1)

[Claims] 1. A cavity having a molded recess, a plurality of liquid flow passages arranged in a row in contact with the outer surface of the cavity, and a hollow cylindrical structure in which the inlet ends of the plurality of liquid flow passages communicate with each other at approximately right angles. a liquid distribution chamber, and a predetermined space within the liquid distribution chamber, which is fixed liquid-tightly when in use, and has a distal end oriented in a direction substantially perpendicular to the orientation direction of the liquid flow passage. A mold comprising a liquid inflow pipe having a projecting length d.