JPH09295315A - Mixing head of mold-casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the mixing head of a mold-casting machine which can control the heat generation of the bearing part of a shaft for a rotor, improve the quality of a polyurethane molding by preventing the generation of polyurethane type foreign matters in particular, and extend the life by preventing a bearing from burning. SOLUTION: In a mixing head, an agitating rotor 6 is arranged freely rotatably in a chamber 5 having introduction ports 3a, 3b in its upper part and a discharge opening 2a in the middle of its lower end part, a shaft 7 connected integrally with the upper end middle part of the rotor 6 is supported freely rotatably through a bearing 8, and at least two kinds of liquid materials are agitated and discharged. The bearing 8 is arranged on the periphery of the lower part of the shaft 7, a cooling chamber 10 is formed above the bearing 8 to make the upper part of the bearing 8 face the inside of the cooling chamber 10, and a cooling tank 15 for a cooling medium C equipped with a built-in cooling mechanism 18 is connected with the cooling chamber 10 by circulating routes 16, 17 having a circulating pump 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to mixing and stirring two or more kinds of liquid materials when molding a resin product using two or more kinds of liquefied raw materials such as a main agent and a curing agent. The present invention relates to a mixing head of a casting machine for discharging (injecting) into a mold or the like, and more particularly to a cooling structure of a bearing portion of a rotor shaft of the mixing head.

[0002]

2. Description of the Related Art For example, when a polyurethane cleaning blade for an electrophotographic copying machine is molded by a mold, a resin liquid as a raw material thereof is prepared by mixing a urethane prepolymer with a curing agent such as a low molecular weight polyol. What is stirred is generally used. 2. Description of the Related Art In the conventional mixing head of an elastomer casting machine, as shown in FIG. 2, for example, a stirring rotor 57 is rotatably mounted in a chamber 51 and is provided on the upper end side of the chamber 51. The liquid material is introduced from the plurality of inlets 52 and 53, mixed and stirred by the rotor 57, and then discharged from the discharge pipe 54 provided at the lower end of the chamber 51. A large number of protrusions 57a are provided on the side circumferential surface of the rotor 57 at intervals, and the lower end of the rotor 57 is formed in a conical shape corresponding to the bottom shape of the chamber 51. Furthermore, the rotor 57
A shaft 58 is integrally connected to the central portion of the upper end of the, and is rotatably supported via a bearing 59.

Although not shown in the drawings, there is a mixing head disclosed in Japanese Patent Laid-Open No. 4-118035 as a prior art. This device is equipped with a cooling jacket around the chamber, but the bearing of the rotor shaft is not provided with cooling means.

[0004]

However, the above-mentioned conventional mixing head has room for improvement in the following points. That is, the mixed liquid in the chamber is heated by the reaction heat generated when the urethane prepolymer and the curing agent such as polyol are mixed and stirred and the heat generated by the friction between the shaft and the bearing. Therefore, the reaction of the mixed liquid in the chamber is promoted without heating the heater attached thereto or controlling the temperature of the heater almost, that is, the temperature in the chamber is hardly controlled. In particular, the heat generated in the bearing portion of the rotor shaft heats a part of the mixed liquid that comes into contact with the upper end of the chamber, so that the hardening of the resin of the mixed liquid is locally promoted, and minute lumps of urethane-based foreign matter are generated. May occur in large quantities. This tendency remarkably appears in the case of a rapid curing type compounded urethane containing a reaction accelerator. When the minute lumps described above are mixed in the urethane molded product, the quality of the product deteriorates. Particularly, in the case of a cleaning blade, since the toner scraping performance is greatly affected, it is necessary to reliably prevent the generation of urethane-based foreign matter. Further, the bearing is seized, so that the service life is short and the bearing must be frequently replaced.

The present invention has been made in view of the above points. By suppressing the heat generation of the bearing portion of the rotor shaft, the generation of urethane-based foreign matter is prevented, and the quality of the urethane molded product is improved. It is an object of the present invention to provide a mixing head of a casting machine capable of preventing seizure of the bearing and extending the life.

[0006]

In order to achieve the above object, the mixing head of the present invention comprises: a) a mixing chamber having a plurality of inlets at the upper end and discharge ports at the center of the lower end, In a mixing head of a casting machine, which rotatably supports a stirring rotor having a shaft integrally connected to the central portion of the upper end through a bearing, and mixes and stirs two or more kinds of liquid substances to discharge them. A bearing is disposed around the lower portion of the shaft, a cooling chamber is provided above the bearing, and an upper end portion of the bearing is exposed to the cooling chamber, and c) a cooling tank for a refrigerant having a cooling mechanism and the cooling chamber. And are connected by a circulation path provided with a circulation pump.

According to the mixing head of the present invention having the above-mentioned structure, by rotating the rotor in the chamber, the introduced two or more kinds of liquid substances are mixed and stirred in the chamber to generate reaction heat. Also, when the rotor rotates, frictional heat is generated between the shaft and the bearing,
Since the bearing is cooled by the refrigerant introduced into the cooling chamber just above the bearing and circulating between the bearing and the cooling tank, the temperature rise of the bearing and its surroundings is suppressed. As a result, the mixed liquid that comes into contact with the bearings in the chamber is not locally heated, so that the generation of minute foreign substances that may occur during mixing and stirring of the urethane mixed liquid in the related art is suppressed. On the other hand, the refrigerant in the cooling chamber absorbs the heat of the bearing and rises in temperature, but when it returns to the cooling tank of the refrigerant, it is cooled by the cooling mechanism and circulated again to the cooling chamber.

As described in claim 2, d) the refrigerant is D
It is preferable to use OP (dioctyl phthalate) or liquid silicone.

In the mixing head according to the second aspect, the refrigerant is D
Due to the use of OP or liquid silicone, especially when the mixed liquid is a urethane type, even if the refrigerant in the cooling chamber may enter (leak) into the chamber through the gap between the bearing and the shaft, the quality is poor. It has no effect.

As described in claim 3, e) a part of the cooling water pipe is formed into a coil shape, the coil portion of the cooling water pipe is inserted into the cooling tank, and an electromagnetic opening / closing valve is provided in the middle of the cooling water pipe. It is possible to configure the cooling mechanism by interposing, and f) provide a temperature sensor in the cooling tank, and open / close the electromagnetic on-off valve based on the temperature detected by the temperature sensor.

In the mixing head according to the third aspect, when the refrigerant, which has absorbed the heat of the bearing in the cooling chamber and rises in temperature, returns to the cooling tank, cooling is performed between the cooling water pipe and especially the cooling water in the coil portion. However, the temperature of the refrigerant in the cooling tank is detected by the temperature sensor, and only when the temperature of the refrigerant becomes higher than the preset temperature, the electromagnetic on-off valve is opened and the cooling water pipe Cooling water flows through the coil portion. Therefore, the temperature of the refrigerant will not be lowered more than necessary.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a mixing head of a casting machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a partial front view showing a mixing head according to an embodiment.

As shown in FIG. 1, the mixing head 1 has a cylindrical casing 2 having a lower portion having an inner peripheral wall whose diameter is gradually reduced downward and an upper end opening of the casing 2 is packed (not shown). ), The cylindrical lid 3 is connected. A through hole 4 is formed in the center of the lid 3, and an inlet 3a for the liquid material A and an inlet 3b for the liquid material B are formed around the through hole 4. Although not shown, a cooling jacket is formed around the casing 2, and a cooling medium (air, water, etc.) inlet is provided on one side of the cooling jacket and a cooling medium outlet is provided on the opposite side. Has been done. A discharge port 2a is opened downward at the center of the lower end of the casing 2.

A chamber 5 is constituted by a space surrounded by the casing 2 and the lid 3, and a stirring rotor 6 is rotatably arranged in the chamber 5. A shaft 7 is integrally connected to the center of the upper end of the rotor 6, and the shaft 7 is supported by penetrating the through hole 4. Further, on the side peripheral surface of the rotor 6, a large number of protrusions 6b are provided at equal intervals in the circumferential direction and at regular intervals in the vertical direction. Further, the lower portion of the rotor 6 is formed in an inverted conical shape corresponding to the bottom portion of the casing 2.

The through hole 4 is composed of a small-diameter hole 4a on the lower side and a large-diameter hole 4b on the upper side. The small-diameter hole 4a is integrally provided with an outward flange 8a at the upper end in this example. A sleeve-shaped bearing 8 is fitted. That is, the shaft 7 is rotatably supported by the bearing 8. A motor (not shown) is connected to the upper end of the shaft 7 to rotate the rotor 6 via the shaft 7.

An annular heater 11 is mounted around the lid 3. The heater 11 is for preventing the liquid material A in the inlet 3a and the liquid material B in the inlet 3b from being hardened by being cooled. Therefore, the temperature sensors 12 are embedded in the vicinity of the inlet 3a and the vicinity of the inlet 3b, respectively, and when at least one of the temperature sensors 12 detects a temperature lower than the set temperature, the heater 11 is activated. ON
become. When the temperature exceeds the set temperature, the heater 11
Is turned off.

A cylindrical member 9 is integrally connected to the upper surface of the lid body 3, and the lower part of the cylindrical member 9 is a chamber communicating with the large diameter hole 4b to form a cooling chamber 10. . A mechanical seal 20 is provided in an upper portion of the cylindrical member 9 so as to surround the shaft 7. An inlet 10a communicating with the cooling chamber 10 is provided at one side of the lower portion of the cylindrical member 9.
However, on the other side, the outlet 10 that also communicates with the cooling chamber 10
b is drilled.

Refrigerant cooling tank 1 separate from mixing head 1
5 is installed, and a predetermined amount of the refrigerant C is stored in the cooling tank 15. At the bottom of the cooling tank 15, a supply port 1
5a, a return port 15b is opened at the upper part, the supply port 15a and the inflow port 10a of the cooling chamber 10 are connected by a supply pipe 16, and the return port 15b and the outflow port 10b.
And are connected by a return pipe 17. A circulation pump 18 is provided in the middle of the supply pipe 16.
Further, in the cooling tank 15, a coil portion 19 of a cooling water pipe is inserted as a cooling mechanism for the refrigerant C, a cooling water supply pipe 19a is connected to one side of the coil portion 19, and a cooling water discharge pipe 19b is connected to the other side. It is connected. An electromagnetic opening / closing valve 21 is provided in the middle of the cooling water supply pipe 19a.

A lid plate 22 is detachably attached to the opening of the cooling tank 15, and the temperature sensor 2 is attached to the lid plate 22.
3 is suspended, and the lower part of the sensor 23 is immersed in the refrigerant C. Further, the temperature sensor 23 and the electromagnetic on-off valve 21 are connected by the electric wiring 24, so that the on-off valve 21 is opened when the temperature of the refrigerant C rises above a predetermined temperature, and the on-off valve 21 is closed when the temperature of the refrigerant C falls below the predetermined temperature. Has become.

Next, a specific use example of the mixing head 1 of the embodiment having the above-mentioned structure will be described.

In the process of manufacturing the cleaning blade made of polyurethane, while introducing the liquid urethane prepolymer A into the chamber 5 through the inlet 3a and the cross-linking agent B into the chamber 5 through the inlet 3b, the rotor 6 is moved. It was rotated at 1500 rpm and mixed and stirred. Refrigerant C is DOP which is compatible with urethane resin liquid.
Alternatively, liquid silicone was used. Although frictional heat is generated between the shaft 7 and the bearing 8 when the rotor 6 rotates, the bearing 8 is cooled by the refrigerant C that is introduced into the cooling chamber 10 and circulates with the cooling tank 15, Almost no increase in temperature occurred. Since the temperature of the mixed liquid of the prepolymer A and the cross-linking agent B in the chamber 5 usually reaches 100 ° C. or higher, the temperature of the refrigerant C also rises considerably, but when returned to the cooling tank 15, the cooling water pipe Coil part 1
It is cooled at 9 and reaches a predetermined temperature. The electromagnetic opening / closing valve 21 of the cooling water supply pipe 19a to the coil portion 19 is provided in the cooling tank 15
When the temperature of the refrigerant C in the inside rises above the set temperature (30 ° C. in this example), the cooling water is automatically released through the temperature sensor 23 and the cooling water flows through the inside of the coil portion 9, so that the refrigerant C is further cooled. As a result, the temperature drops. The mixed liquid mixed and stirred in the chamber 5 as described above was discharged from the discharge pipe 2a into a predetermined mold (not shown) to form a blade.
Unlike the blade cast using the conventional mixing head (FIG. 2), generation of minute foreign matter was hardly seen, and a high quality product was obtained.

By the way, in the above embodiment, the case where the polyurethane resin solution is mixed and stirred has been described as an example.
The resin liquid that can be used in the mixing head 1 of the present invention is not limited to the examples, and can be used in a casting machine for mixing and stirring various resin liquids.

[0023]

As is apparent from the above description,
The mixing head of the casting machine of the present invention has the following effects.

(1) Since the heat generation of the bearing portion of the shaft is suppressed, the generation of urethane-based foreign matter is particularly prevented, the quality of the urethane molded product is improved, and seizure of the bearing is prevented, so that the life of the bearing is shortened. Extend.

(2) In the mixing head according to the second aspect, when the mixed liquid is a urethane type, even if the refrigerant in the cooling chamber leaks into the chamber through the gap between the bearing and the shaft, the quality is adversely affected. It has no effect.

(3) In the mixing head according to the third aspect, the cooling water flows in the coil portion of the cooling water pipe only when the temperature of the refrigerant becomes higher than the set temperature, so that the temperature of the refrigerant is cooled more than necessary. There is nothing to do.

[Brief description of drawings]

FIG. 1 is a front view, partly in section, showing a mixing head of a casting machine according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional general mixing head.

[Explanation of symbols]

 1 ... Mixing head 2 Casing 3 Lid body 6 Rotor 7 Shaft 8 Bearing 10 Cooling chamber 15 Cooling tank C Refrigerant

Claims (3)

[Claims] 1. A mixing rotor having a plurality of inlets at the upper end and a discharge port at the center of the lower end, and a stirring rotor having a shaft integrally connected to the center of the upper end is rotated through a bearing. In a mixing head of a casting machine that freely supports and mixes and agitates two or more kinds of liquid substances, the bearing is arranged around the lower part of the shaft, and a cooling chamber is provided above the bearing to The upper end of the bearing is exposed to the cooling chamber, and the cooling tank of the refrigerant provided with a cooling mechanism and the cooling chamber,
A mixing head of a casting machine, which is connected by a circulation path provided with a circulation pump. 2. The mixing head of a casting machine according to claim 1, wherein DOP or liquid silicone is used as the refrigerant. 3. A part of the cooling water pipe is formed in a coil shape, the coil part of the cooling water pipe is inserted into the cooling tank, and an electromagnetic opening / closing valve is provided in the middle of the cooling water pipe, The mixing head of a casting machine according to claim 1 or 2, wherein a cooling mechanism is configured, a temperature sensor is provided in the cooling tank, and the electromagnetic on-off valve is opened / closed based on a temperature detected by the temperature sensor.