JPS628287B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal mold that is used, for example, when controlling the mold temperature by supplying a heat medium such as oil or water to a mold installed in a synthetic resin molding machine. The present invention relates to a mold temperature control device.

Molds equipped with this type of temperature control device include:
The pressurized circulation type uses a circulation pump to supply pressurized heating medium to the mold, and the circulation pump installed on the discharge side of the mold sucks the heating medium passing through the mold. There is also a suction circulation type. The above-mentioned pressurized circulation mold is divided into multiple directions because it is necessary to fit O-rings, etc. to each connection part of the medium passage that connects at the mating surface of the mold to maintain a high sealing performance of the passage. In the case of a mold with a complicated structure, it is difficult to form a medium passage, and a suction circulation type mold can be used even if the sealing performance of the connection part is poor because the heat medium passing through the mold is sucked by the pump. There is no problem,
Since the installation of an O-ring can be omitted, it is possible to manufacture a complex mold with many dividing directions in which medium passages are formed at high density and the temperature can be easily controlled. However, in general, pressurized circulation type molds with a simple structure are often used.
Therefore, it was necessary to manufacture two models, a pressurized circulation type and a suction circulation type, depending on the mold that also uses the temperature control device. Install two pumps, a circulation pump and a suction circulation pump, so that one model can be used for both purposes, or install a circulation pump whose rotation direction can be switched between forward and reverse so that it can be used selectively. A new temperature control device appeared. The former is expensive because it has two pumps and an associated circuit, while the latter has two pumps and an associated circuit, and the latter switches the flow of the heat medium between forward and reverse within one medium circuit, so the pressure within the circuit also increases. There were disadvantages such as forward and reverse polarity, which accelerated or reduced the deterioration of the sealing properties of various parts of the circuit, and the need to use a thermometer for controlling mold temperature in both forward and reverse directions.

The present invention connects a circulation pump to the discharge circuit for the medium from the mold, and connects the medium tank to the discharge side of the pump by opening the inside of the tank to atmospheric pressure or airtightly sealing the tank. By adding a switching valve, a mold temperature control device is provided in which one temperature control device can be used for pressurized circulation and suction circulation.

The second invention of the present application also provides a method for closing the circuit between the medium tank and the medium supply circuit to the mold in the first invention when replacing the mold or cleaning the medium passage of the mold. By providing an on-off valve for shutting off and a secondary air supply valve, the residual medium in the mold can be easily removed. A fourth invention of the present application is characterized in that a pot is provided for accommodating the medium that overflows the medium tank by the above-mentioned method, and a reflux circuit is provided for refluxing the medium from the pot to the circulation circuit. The invention is characterized in that the pot and the reflux circuit are connected to the circulation circuit in parallel with the medium tank.

The present invention will now be described with reference to the drawings.

In FIG. 1 showing an embodiment, 1 consists of a movable mold 1a and a fixed mold 1b, each of which has medium passages a and b, and S represents the medium passages a and b.
an airtight medium tank 2 which heats or cools the heat medium of water or oil passing through b and supplies it to the mold 1, and the outlet of the tank 2 communicates with the passages a and b of the mold 1. A supply circuit 3, a discharge circuit 4 connected to the discharge side of the mold 1, and a circulation pump 5 which rotates in one direction with the suction side connected to the discharge circuit 4 and the medium tank 2 connected to the discharge side. The configured medium circulation circuit, 6 is a heater for heating the medium in the medium tank 2, 7 is also a cooling waterway, 8 is a supply waterway when water is used as a medium, 9 is a medium tank 2
10 is a switching valve attached to the medium tank 2 via this switch 9, and 11 is connected to this switching valve 10, and is opened to atmospheric pressure to open the discharge valve 11'. A prepared pot,
Reference numeral 12 denotes a circulation circuit for returning the medium contained in the pot 11 to the circulation circuit S. Note that the pot 11, the recirculation circuit 12, and the switching valve 10 may be configured as shown by the phantom lines in the figure to directly return the overflowing medium to the medium tank 2.
13 is interposed on the supply circuit 3, and is connected to the supply circuit 3 when replacing the mold 1 or cleaning the medium passage of the mold.
14 is a secondary air supply valve that supplies outside air to the circuit 3 when the valve 11 is closed, and 15 is a temperature measuring device connected to the outlet side of the medium tank 2.

In this embodiment having the above configuration, the switching valve 1
0 is closed to drive the circulation pump 5, the pressurized supply type circulation circuit S becomes a closed circuit, and the pump 5
After the pressurized medium undergoes heat exchange in the medium tank 2, it is supplied to the mold 1 while maintaining the pressure,
Circulation is performed through passages a and b and returning to the same pump 5 again. To explain this according to Figure 3,
The medium (including gases such as air; hereinafter referred to as medium pressure) pressurized by the circulation pump 5 is fed into the medium tank 2 at a positive pressure higher than atmospheric pressure, as shown by the solid line a.

Next, in the supply circuit 3 from the medium tank 2 to the mold 1, the medium pressure is lower than in case a due to pressure loss due to transportation distance, piping resistance, etc., and becomes a positive pressure as shown in b. The medium is fed into the mold 1 under this positive pressure state.

The medium pressure discharged from the mold 1 is
In the discharge circuit 4 from the to the circulation pump 5, the above-mentioned b
For the same reason, the pressure drops further than point b, reaches the same pressure as atmospheric pressure halfway through the discharge circuit 4, as shown in c, and finally reaches a negative pressure lower than atmospheric pressure (dotted line in the figure). ) with the circulation pump 5 side (in)
be sucked into.

In addition, in the supply circuit 3 on the upstream side of the mold 1,
The medium pressure never becomes negative pressure.

Furthermore, when operating with the switching valve 10 open, the medium pressurized by the circulation pump 5 is released to atmospheric pressure in the medium tank 2, while the negative pressure generated on the suction side of the pump 5 causes Discharge circuit 4, mold passage a,
b. A suction circulation type circuit S is formed in which the medium is sucked and circulated from the supply circuit 3 and the bottom of the tank 2. To explain this according to FIG. 4, the pressure of the medium pressurized by the circulation pump 5 is released to the atmosphere through the switching valve 10, so that the pressure of the medium becomes lower than the initial positive pressure state, as shown in solid line (b) a. The pressure in the tank 2 becomes the same as the atmospheric pressure.

On the other hand, the supply circuit 3 from the bottom of the medium tank 2,
By the suction force of the circulation pump 5, a negative pressure circuit is formed as shown in b and c between the mold 1 and the discharge circuit 4, and the medium is sucked into the mold 1 under negative pressure, and the medium is transferred to the suction side of the circulation pump 5. circulate.

Note that the medium is under positive pressure (pressurization) in the supply circuit 3.
It will never be transported. Medium tank 2 is switching valve 1
0 opens to the atmosphere, the positive pressure in route B is lost from the out side of the circulation pump 5 and becomes atmospheric pressure, and thereafter becomes negative pressure due to the suction force of the circulation pump 5.

When replacing the mold or cleaning the medium passages a and b in the mold, the on-off valve 13 is closed, the switching valve 10 and the air supply valve 14 are opened, and the pump 5 is driven. The medium remaining in b flows into the medium tank 2 together with the outside air supplied from the air supply valve 14, overflows the tank 3, and the overflow amount of medium is stored in the pot 11. The medium stored in this pot 11 is returned to the circulation circuit S by opening the discharge valve 11' after completing work such as replacing the mold.

Next, an embodiment will be described with reference to FIG. 2, in which the medium tank 2, the pot 11 for the medium overflowing the tank 2, and its reflux circuit 12 are connected in parallel to the circulation circuit S.

In this Figure 2, 16 is an overflow circuit that guides the medium overflowing from the medium tank 2 to the pot 11, and 17 is provided on the circuit 16, and the circuit 16 is normally closed and opened when replacing the mold, etc. The valve 10b is a release valve that opens and closes in the opposite direction to the switching valve 10 to open the pot 11 to atmospheric pressure or close it airtightly, and 18 is another float switch provided inside the pot 11.

This embodiment has almost the same structure as the previous embodiment except for the connection portion of the pot 11, so common members are denoted by the same reference numerals and explanations of the respective parts will be omitted. Also, valve 1
7 is closed, a pressurized supply type circulation circuit S is formed by closing the switching valve 10, and a suction circulation circuit S is formed by opening the same valve 10.
The same applies to switching to . When replacing the mold, etc., close the switching valve 10 and the on-off valve 13, open the open valve 10b and the air supply valve 14, and
When the valve 17 is actuated to open the overflow circuit 16 and the circulation pump 5 is activated, the medium overflowing the medium tank 2 is accommodated in the pot 11. The medium in the pot 11 is returned to the circulation circuit S by closing the valve 17 and opening the discharge valve 11' to drive the circulation pump 5. When the float switch 18 is activated due to a drop in the liquid level in the pot 11, the medium is discharged. The valve 11' and the release valve 10b are closed, the switching valve 10 is opened, and the circulation circuit S starts operating in a normal suction circulation type. In addition, when using the pressurized supply type, the switching valve 10 is closed and the operation is performed.

Note that when implementing the present invention, when configuring an apparatus that uses water as a medium, it is possible that the medium that overflows the medium tank during mold replacement etc. may be discharged outside the system without being returned to the circulation circuit. Needless to say.

According to the present invention configured as described above and used as described above, the structure and operation are simple, low cost, and compact,
It is possible to manufacture a mold temperature control device that can be used for both pressurized circulation type and suction circulation type.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a circuit diagram schematically showing the embodiment, FIG. 2 is a circuit diagram of the embodiment, and FIG. 3 shows pressure fluctuations in a pressurized supply type circulation circuit. FIG. 4 is an explanatory diagram showing the state of pressure fluctuation in the suction circulation type circuit. 1...Mold, 1a...Movable mold, 1b...Fixed mold, a, b...Medium passage, S...Circulation circuit, 2
... Medium tank, 3 ... Supply circuit, 4 ... Discharge circuit, 5 ... Circulation pump, 6 ... Heater, 7 ... Cooling waterway, 8 ... Supply waterway, 9 ... Float switch, 10 ... Switching Valve, 10b...Release valve, 1
1...Pot, 11'...Discharge valve, 12...Recirculation circuit, 13...Opening/closing valve, 14...Air supply valve, 5...
Temperature meter, 16... Overflow circuit, 17...
Valve, 18...Float switch.

Claims (1)

[Scope of Claims] 1. A circulation pump is connected to the discharge circuit for the medium from the mold, and a medium tank connected to the discharge side of the pump is provided with the tank being open to atmospheric pressure or airtightly sealed. A mold temperature control device characterized by being equipped with a switching valve that controls the temperature of the mold. 2. A circulation pump is connected to the discharge circuit for the medium from the mold, and a switching valve is attached to the medium tank connected to the discharge side of the pump to open the tank to atmospheric pressure or to airtightly seal it. , wherein an on-off valve for closing the circuit when replacing the mold and a secondary air supply valve are provided between the medium tank and the circuit for supplying the medium to the mold. Mold temperature control device. 3. A circulation pump is connected to the discharge circuit for the medium from the mold, and a switching valve is attached to the medium tank connected to the discharge side of the pump to open the tank to atmospheric pressure or to airtightly seal it. In a mold temperature control device, an on-off valve for closing the circuit when replacing the mold, and a secondary air supply valve are provided between the medium tank and the medium supply circuit to the mold. 2. A temperature control device comprising: a pot for accommodating the medium that overflows the medium tank when the on-off valve is closed; and a reflux circuit for refluxing the medium from the pot to the circulation circuit. 4. A circulation pump is connected to the discharge circuit for the medium from the mold, and a switching valve is attached to the medium tank connected to the discharge side of the pump to open the tank to atmospheric pressure or to airtightly seal it. Between the medium tank and the medium supply circuit to the mold, an on-off valve and a secondary air supply valve are provided to close the circuit when replacing the mold, etc. Therefore, in a mold temperature control device that is provided with a pot for accommodating a medium that overflows a medium tank and a reflux circuit that refluxes the medium from the pot to the circulation circuit, the pot and the reflux circuit are connected to the medium tank. A temperature control device, characterized in that it is connected in parallel to the circulation circuit.