JPH08200915A - Cooler - Google Patents

Abstract

PURPOSE: To provide a cooler which enables cooling efficiently by depriving a member to be cooled of heat by heat of vaporization of a liquefied refrigerant. CONSTITUTION: This cooler is constituted of a refrigerant tank 29, cooling units 10a and 10b which are provided on a core body 7 heated to vaporize the liquefied refrigerant supplied from the refrigerant tank 29 so that the core body 7 is cooled by heat of vaporization obtained and a heat exchanger 31 which cools and liquefies the refrigerant vaporized by the cooling units 10a and 10b to be circulated back to the refrigerant tank 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding, a mold for die casting, a mold for casting, and a cooling device for various industrial equipment.

[0002]

2. Description of the Related Art A mold for molding a plastic molded product will be described as an example. The mold body comprises a fixed mold and a movable mold, and a cavity is provided in the mold body. High-temperature heated molten resin injected from the nozzle of the injection molding machine is injected into this cavity through a sprue and a runner provided in the fixed mold.

Therefore, it is necessary to heat the periphery of the sprue and runner so that the molten resin does not solidify,
On the contrary, the periphery of the cavity needs to be cooled in order to accelerate the solidification of the molten resin. For cooling the mold body, a cooling water channel is provided in the mold body around the cavity, and cooling water is circulated through this cooling water channel to remove heat from the cooling water. The resin is cooling.

When it is necessary to cool the local part faster than the other parts by using both the cooling means for the cooling water flowing through the cooling water passage and the cooling means by the heat pipe, the heat pipe is attached to the local part. It is also known that the heat absorbing part is located and the heat radiating part is cooled by cooling water. Further, there is also a method of using a refrigerant to remove heat by the heat of vaporization of the refrigerant.

[0005]

However, among the above-mentioned cooling means, the method of providing a cooling water channel in the mold body and circulating the cooling water in this cooling water channel is the most general, but the cooling efficiency is poor. , Can not be sufficiently cooled unless a large amount of cooling water is distributed. Therefore, the molding cycle time until the molten resin injected into the cavity is solidified and the molded product is taken out is long and the productivity is poor. Further, it is difficult to form holes for providing a large number of cooling water passages on the mold body,
This is a cause of increased die cost.

Further, the cooling means using a heat pipe is limited to local cooling in terms of cost and cannot cool the entire mold body, and is not suitable for a mold for molding a large molded product. is there. Further, the method using a refrigerant has a high cooling efficiency, but unless an appropriate amount of the refrigerant is supplied in proportion to the temperature, there is a risk of overcooling, and it is difficult to control the temperature.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cooling device capable of efficiently cooling by utilizing the heat of vaporization of a liquefied refrigerant. .

[0008]

In order to achieve the above object, the present invention provides a cooling member, a coolant supply source provided outside the cooling member, and the cooling member. A pressure reducing device provided outside the device, and a liquefied refrigerant supplied to the heated member to be cooled, which is supplied from the refrigerant supply source, is vaporized by the pressure reducing device, and the heat of vaporization causes the member to be cooled. And a heat exchanger for cooling and liquefying the vaporized refrigerant vaporized by the cooling unit and returning the vaporized refrigerant to the refrigerant supply source.

The refrigerant supply source is a refrigerant tank whose pressure is reduced by a pressure reducing device. The member to be cooled is a molding die, and is provided with a cooling unit in the vicinity of a cavity filled with the hot melt resin.

The cooling unit is a wick which is set in a cooling hole provided in a member to be cooled and which allows a liquefied refrigerant to permeate by a capillary phenomenon. Further, a plurality of the cooling units are provided on the member to be cooled and are communicated with each other through a refrigerant flow passage connected in series or in parallel.

That is, the cooling device of the present invention is characterized by utilizing the relationship between the intrinsic temperature and vapor pressure of the refrigerant by adjusting the pressure of the refrigerant tank as the refrigerant supply source. A table showing the equilibrium relationship between water gas and liquid is as follows.

Vapor pressure temperature (℃) 0.006 0 0.012 10 0.023 20 0.042 30 0.077 40 0.122 50 0.197 60 0.308 70 0.468 80 0.692 90 1.000 100 When the inside of the cooling circuit is maintained at 0.122 gauge pressure, the temperature inside the cooling circuit is 50 At ° C, the vapor and liquid parts of water are in equilibrium. When the temperature in the cooling circuit reaches 60 ° C under the same pressure condition, the vapor pressure is balanced at 0.197 gauge pressure and the pressure difference is 0.07
Since there are five, the liquid inside the cooling circuit has the power to become vapor. When the liquid layer becomes vapor, water takes heat from the mold body as heat of vaporization. The larger the pressure difference in the downward direction, the greater the force that the liquid tends to become vapor.

Further, since the set pressure and the liquid layer and the vapor layer are kept in equilibrium by keeping the atmospheric pressure constant, the vapor and the liquid layer at the set pressure are in equilibrium, and further vapor generation is performed. Absent. Therefore, steam is not generated, and the heat of vaporization is not taken away. Therefore, the temperature does not drop below the set temperature.

In other words, the heat transfer flows from the larger temperature difference to the smaller temperature difference. However, this is said when the pressure is constant at atmospheric pressure, but when the pressure changes even when the temperature is constant, heat flows from the higher pressure side to the lower pressure side. By keeping the pressure constant, the die holding temperature can be maintained, and by adjusting the pressure, the die temperature can also be adjusted.

Further, even if the refrigerant is not water, this principle can be used when other substances are liquid at room temperature. Examples of ethyl alcohol and benzene are as follows. (Ethyl alcohol) (Benzene) Vapor pressure temperature (℃) Vapor pressure temperature (℃) 0.017 0 0.035 0 0.058 20 0.098 20 0.176 40 0.238 40 0.461 60 0.813 60 1.068 80 0.992 80 2.226 100 1.768 100

[0016]

When the liquefied refrigerant supplied from the refrigerant supply source is decompressed by the decompression device and supplied to the cooling section provided on the heated member to be cooled, it is vaporized by the heat of the member to be cooled and the heat of vaporization causes The member to be cooled is cooled. The vaporized refrigerant vaporized by the cooling unit flows out of the member to be cooled and is guided to the heat exchanger, where the vaporized refrigerant is cooled and liquefied again, and the liquefied refrigerant is returned to the refrigerant supply source.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment, and FIG.
Indicates a cooling device for the molding die. Reference numeral 1 denotes a mold body, which is composed of a fixed mold 2 and a movable mold 3. A cavity 4 into which the heated molten resin is injected is provided between the fixed mold 2 and the movable mold 3.

The fixed mold 2 has a sprue 5 having a nozzle touch surface that comes into contact with a nozzle (not shown) of an injection molding machine.
Is provided, and the sprue 5 communicates with the cavity 4 via a runner 6. The movable mold 3 is provided with a core body 7 and an ejector plate 8 as members to be cooled which form the cavity 4, and the ejector plate 8 has an ejector pin 9 penetrating the core body 7 and extending to the cavity 4. It is provided.

A plurality of core units 7 are provided in the core body 7, and in this embodiment, two sets of cooling units 10a, 1 are provided.
0b is provided. These cooling units 10a, 1
Since 0b has the same structure, one of them will be described. As shown in FIG.
From the side toward the cavity 4, a bottomed cylindrical cooling hole 12
Has been drilled.

On the inner peripheral surface of the cooling hole 12, a wick 13 having a cylindrical shape and having an open-celled substance (porous shape) is housed, and an inner cylinder 14 is inserted on the inner peripheral surface of the wick 13. The inner cylinder 14 is, for example, a net-like body made of stainless steel, and has an elastic force in the radial expansion direction. It is in close contact.

An opening side of the cooling hole 12, that is, a portion adjacent to the movable side mold plate 11 is formed in a large diameter portion 15,
A step 16 is formed between the cooling hole 12 and the inner peripheral surface thereof. The large-diameter portion 15 has an inner ring body 1 that supports the inner cylinder 14.
7 is stored. The inner ring body 17 is composed of a flange portion 17a closely fitted to the large-diameter portion 15, a cylindrical portion 17b fitted to the outer peripheral surface of the end of the inner cylinder 14, and a communication port 17c communicating with the inside of the inner cylinder 14. Has been done.

An outer ring body 18 is fitted in the cylindrical portion 17b of the inner ring body 17. The outer ring body 18 is composed of a flange portion 18a that is closely fitted to the large-diameter portion 15 and is in contact with the step 16, and a tubular portion 18b that is fitted to the tubular portion 17b with a gap 19 therebetween. Therefore, the inner ring body 17 and the outer ring body 18 are fitted so as to face each other, and the annular passage 20 is formed between the flange portions 17a and 18a of both. The annular passage 20 communicates with the gap 19 through a through hole 21 provided in the tubular portion 18b.

Further, the annular passage 20 communicates with a refrigerant inflow passage 22 penetrating the core body 7 and the movable mold plate 11, and the communication port 17c communicates with a refrigerant outflow passage 23 provided in the movable mold plate 11. are doing.

The cooling unit 10a constructed in this way
And 10b, the annular passages 20 communicate with each other through a communication port 24, and the communication port 17c of the cooling unit 10b also communicates with the refrigerant outflow passage 23.

Further, as shown in FIG. 1, the refrigerant inflow passage 22 has a refrigerant inflow pipe 25 penetrating a side portion of the fixed mold 3.
Is connected. This refrigerant inflow pipe 25 is a joint 2
It is connected to one end of a pipe 27 outside the mold body 1 via 6. A first valve 28 is provided in the middle of the pipe 27, and the other end of the pipe 27 is connected to the bottom of a refrigerant tank 29 as a refrigerant supply source.

The refrigerant tank 29 is a hermetically sealed container in which the refrigerant is stored. As the refrigerant, for example, a hydrocarbon alcohol, benzene, chlorofluorocarbon, or the like that is liquid at room temperature is desirable. Inside the refrigerant tank 29, the liquefied refrigerant is contained in the lower layer and the air is contained in the upper layer in a separated state.

A first port 30a and a second port 30b are provided on an upper side wall of the refrigerant tank 29, that is, a portion corresponding to an upper air layer, and a third port 3 is provided on the upper lid.
0c is provided. The heat exchanger 3 is provided between the first port 30a and the refrigerant outflow passage 23 of the mold body 1.
1 is connected.

That is, the heat exchanger 31 includes a spiral pipe 33 inside a cylindrical container body 32 for containing cooling water.
The upper end of the pipe 33 is connected to the refrigerant outflow passage 23 through the pipe 34, and the lower end of the pipe 33 is connected to the first port 30a of the refrigerant tank 29 through the pipe 35. ing. A cooling water inlet 36 is provided on the lower side wall of the container body 32, and a cooling water outlet 37 is provided on the upper side wall.
Is provided and the vaporized refrigerant flowing inside the pipe 33 is cooled and liquefied by the cooling water flowing into the container body 32 from the cooling water inlet 36.

Further, the second port 30b of the refrigerant tank 29 is connected to the bottom of the sub tank 39 via the pipe 38. The upper part of the sub tank 39 is connected to a decompression pump 42 as a decompression device via a pipe 41 having a second valve 40 in the middle. A pressure gauge 43 is provided in the sub-tank 39, and the pressure gauge 43 is connected to a motor 45 that drives a decompression pump 42 via a controller 44, and the motor 45 keeps the pressure in the sub-tank 39 within a set pressure range. Is on / off controlled.

Further, the third port 30 of the refrigerant tank 29
A refrigerant replenisher 48 is provided in c through a pipe 47 having a third valve 46. A return pipe 49 is connected in the middle of the pipe 47. The return pipe 49 is connected to the cooling unit 10b of the mold body 1 so that excess refrigerant can be returned to the cooling tank 29. There is. Therefore, the pump 50 is provided in the middle of the return pipe 49.

Next, the operation of the cooling device constructed as described above will be described. When the high-temperature heated molten resin injected from the nozzle of the injection molding machine is injected from the sprue 5, the heated molten resin is filled in the cavity 4 via the runner 6, and the heated molten resin causes the fixed mold 2 and The movable mold 3 is heated to a high temperature. On the other hand, at this time, the liquefied refrigerant stored in the refrigerant tank 29 flows into the refrigerant inflow pipe 25 through the pipe 27, and further, the refrigerant inflow path 22.
Through the through hole 21 to the wick 13 inside the cooling hole 12. Since the wick 13 is porous, the liquefied refrigerant permeates by the capillary phenomenon.

When the liquefied refrigerant permeates the wick 13,
Since the liquefied refrigerant is vaporized by receiving the heat of the core body 7, the heat of vaporization removes the heat of the core body 7 and cools the core body 7. When the liquefied refrigerant is vaporized, the volume expands, the vapor pressure rises, enters the inner cylinder 14 inside the wick 13, and the vaporized refrigerant is guided to the refrigerant outflow passage 23 via the communication port 17c.

The vaporized refrigerant in the refrigerant outlet passage 23 is guided to the pipe 33 of the heat exchanger 31 via the pipe 34. At this time, the inside of the container body 32 is filled with cooling water, and moreover, since it is constantly supplied from the cooling water inlet 36, the vaporized refrigerant flowing through the pipe 33 is cooled and returns to the liquefied refrigerant. When the vaporized refrigerant returns to the liquefied refrigerant, the volume becomes smaller,
The vaporized refrigerant can be sucked by the pressure reducing action. The liquefied refrigerant that has been heat-exchanged by the heat exchanger 31 is stored in the refrigerant tank 29 through the pipe 35 and flows into the cooling unit 10a of the mold body 1 again. Further, the surplus refrigerant in the refrigerant unit 10b is returned to the refrigerant tank 29 via the return pipe 49.

Thus, the refrigerant tank 29 is provided, and the pressure thereof is adjusted by the decompression tank 39 as a decompression device, so that the characteristic relationship between the refrigerant temperature and the vapor pressure is utilized. 0.12 in the cooling circuit
When kept at 2 gauge pressure, when the temperature inside the cooling circuit is 50 ° C, the vapor part and the liquid part of water become in equilibrium. When the temperature in the cooling circuit reaches 60 ° C under the same pressure condition, the vapor pressure is 0.19
Since it is in equilibrium at 7 gauge pressure and there is a pressure difference of 0.075, the liquid inside the cooling circuit has a force to become vapor. When the liquid layer becomes steam, water takes heat from the mold body 1 as heat of vaporization. The larger the pressure difference in the downward direction, the greater the force that the liquid tends to become vapor.

Further, since the set pressure is kept in equilibrium with the liquid layer and the vapor layer by keeping the atmospheric pressure constant, the vapor at the set pressure and the liquid layer are in equilibrium, and further vapor generation is performed. Absent. Therefore, steam is not generated, and the heat of vaporization is not taken away. Therefore, the temperature does not drop below the set temperature. In other words, the holding temperature of the mold main body 1 is maintained by keeping the pressure constant, and the mold main body 1 is adjusted by adjusting the pressure.
The temperature of can also be adjusted.

Therefore, the mold body 1 heated by the heated molten resin can be cooled by the vaporizing action of the liquefied refrigerant, and the thermal efficiency can be improved as compared with the conventional method of cooling with cooling water, and the cavity The heat-melted resin filled in No. 4 can be cooled and solidified in a short time, and the molding cycle time can be shortened.

FIG. 3 shows a second embodiment. The same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. A cooling hole 51 is provided in the core body 7, and a cylindrical wick 52 having a bottom is provided on the inner peripheral surface of the cooling hole 51 so as to cover the entire surface thereof. The movable side template 11 is in contact with the opening end surface of the wick 51.
The wick 52 is fixed by pressing it against the cooling hole 51.

In the cavity 53 of the wick 52, a plurality of, and in this embodiment, two vaporized refrigerant discharge pipes 54 projecting from the movable side mold plate 11 are inserted. The vaporized refrigerant discharge pipe 54 has an upper end opened to the cavity 53 of the wick 52, and a lower end communicated with the refrigerant outflow passage 23 through the communication port 17c. In addition, the refrigerant inflow passage 2 is provided on the side of the core body 7.
2 is provided with a through hole 55, which communicates with the outer layer of the wick 52.

Further, the wick 52 is made of a granular material such as porous sintered metal, particulate ceramics, sand, etc., which is hardened by an adhesive agent, or metal fiber, glass fiber, plastic fiber is hardened by an adhesive agent. It is sufficient that the liquefied refrigerant penetrates due to the capillary phenomenon.

FIG. 4 shows the third embodiment, where 61 is a pipe for supplying vaporized refrigerant to the heat exchanger, and 62 is a return pipe for returning the excess liquid refrigerant to the refrigerant tank. The pipe 61 and the return pipe 62 are arranged in parallel, and both pipes 61, 6
A plurality of cooling pipes 63 are connected in parallel between the two.

The refrigerant supply pipe 6 is provided on the side of the pipe 61.
4 are arranged, and this refrigerant supply pipe 64 is connected to the pipe 6
It is connected to each cooling pipe 63 via 5. An upper stopper 66 and a lower stopper 67 are provided at the upper and lower ends of each cooling pipe 63. Then, the upper pipe 66 has a cooling pipe 63.
A connection pipe 68 is provided for supplying the vaporized refrigerant vaporized therein to the pipe 61, and a lower pipe 67 is provided with a connection pipe 69 for supplying the excess liquid refrigerant not vaporized in the cooling pipe 63 to the return pipe 62. ing.

Therefore, the liquefied refrigerant is the refrigerant supply pipe 64.
From the space between the inner wall of each cooling pipe 63 and the upper plug 66 through the pipe 65, and the liquefied refrigerant to the extent that the inner surface of the cooling pipe 63 gets wet. The liquefied refrigerant is vaporized by the heat around the cooling pipe 63, and the vaporized refrigerant is guided to the pipe 61 via the connection pipe 68 and supplied to the heat exchanger. Further, the excess liquid refrigerant that has not been vaporized in the cooling pipe 63 is supplied to the return pipe 62 via the connection pipe 68 and returned to the refrigerant tank.

When the inner peripheral surface of the cooling pipe 63 cannot be uniformly wetted by the liquefied refrigerant, a wick may be provided on the inner peripheral surface of the cooling pipe 63 as shown in the first and second embodiments. Good.

Further, in each of the above-mentioned embodiments, the core portion of the molding die is provided with the cooling portion so as to cool the core. However, in the present invention, the die casting die, the casting die or the cooling die is cooled. It can be applied to all necessary industrial equipment.

[0045]

As described above, according to the present invention, the temperature of the member to be cooled can be adjusted by adjusting the pressure, and the member to be cooled can be cooled efficiently.
Therefore, by adopting this cooling device for cooling the molding die, it is possible to improve the thermal efficiency as compared with the conventional method of cooling with cooling water, and to heat the molten resin filled in the cavity in a short time. There is an effect that it can be cooled and solidified, and the molding cycle time can be shortened.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a cooling device showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the cooling unit according to the embodiment.

FIG. 3 is a vertical sectional front view of a cooling unit according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional front view of a cooling unit according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mold main body, 7 ... Core main body, 10a, 10b ... Cooling unit, 12 ... Cooling hole, 14 ... Wick, 29 ... Refrigerant tank, 31 ... Heat exchanger.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F25D 9/00 D F28D 15/02 101 K

Claims (5)

[Claims] 1. A member to be cooled, a coolant supply source provided outside the member to be cooled, a pressure reducing device also provided outside the member to be cooled, having a pressure control function, and the heated member to be cooled. The liquefied refrigerant supplied from the refrigerant supply source provided in the member is vaporized by the decompression device,
A cooling device comprising: a cooling unit that cools the member to be cooled by the heat of vaporization; and a heat exchanger that cools the liquefied vaporized refrigerant vaporized by the cooling unit to liquefy it and return it to the refrigerant supply source. . 2. The cooling device according to claim 1, wherein the refrigerant supply source is a refrigerant tank whose pressure is reduced by a pressure reducing device. 3. The cooled member is a molding die,
The cooling device according to claim 1, further comprising a cooling unit near the cavity filled with the hot melt resin. 4. The cooling device according to claim 1, wherein the cooling unit is a wick that is set in a cooling hole provided in a member to be cooled and that allows a liquefied refrigerant to permeate by a capillary phenomenon. 5. The cooling device according to claim 1, wherein a plurality of the cooling units are provided on the member to be cooled and are communicated with each other through a refrigerant flow passage connected in series or in parallel.