JPS6234744Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a mold temperature control device for controlling the mold temperature by circulating a heat medium such as oil or water in a mold installed in an injection molding machine, for example. It is related to.

Problems that the invention aims to solve Conventionally, mold temperature controllers use heat exchangers for heating and cooling to adjust the temperature of the heat medium (water, oil, etc.) circulating inside the mold. It is installed in a medium tank installed in the circuit, and its heating and cooling capabilities are controlled according to the set temperature of the mold.

However, in general, a heater is used to heat this heat medium, and cooling water is used to cool it, so as shown in Figure 3, the heating capacity is proportional to the heat receiving capacity from the heater, so this is not a big problem. However, since the cooling capacity uses the temperature difference between the heat medium and the cooling water, it is zero when the set temperature and the cooling water temperature are equal, and in a high set temperature range, the difference between the cooling water temperature and is large, and the cooling capacity becomes extremely large; however, in a low set temperature range, the difference with the cooling water temperature is small, and the cooling capacity becomes extremely small.
Therefore, even if the cooling capacity (amount of cooling water) is constant, the temperature change of the heat medium in the high temperature range is greater than the change in the temperature of the heat medium in the low temperature range. For this reason, if the cooling capacity is large, the temperature change of the heat medium will be large, and no matter how high-precision the controller is, the heat medium will become too cold and will need to be reheated by a heater, and this repeated process will cause a hunting phenomenon. It's hard to avoid. On the other hand, if the cooling capacity is small, it will take a long time to adjust the temperature in a low temperature range, making it difficult to quickly adjust the temperature of the heat medium.

In other words, in the conventional mold temperature control device, when cooling the heat medium, it is not possible to appropriately automatically adjust the cooling capacity so that it is small in a high set temperature range and large in a low set temperature range. Problems such as instability of the heat medium temperature due to the hunting phenomenon caused by overcooling or delays in temperature adjustment of the heat medium due to insufficient cooling capacity were inevitable.

Purpose of the invention The present invention was devised to solve the above-mentioned problems of the conventional technology.It ensures a high cooling capacity in a low set temperature range, and also controls excessive cooling capacity in a high set temperature range. It is an object of the present invention to provide a mold temperature control device that can thereby prevent the hunting phenomenon caused by instability of the medium temperature and can quickly control the temperature of the heat medium.

Structure of the invention The invention provides a heat exchanger consisting of a cooler and a heater in a medium tank installed in the mold temperature control circuit.
A mold temperature control device in which the heat exchanger is controlled by a controller according to a set temperature range,
A supply circuit is connected to one end of the cooling coil constituting the cooler, and discharge circuits are connected by branching from a plurality of positions of the cooling coil having different lengths from the supply circuit side, and each discharge circuit is connected to a selected one. It is characterized by being equipped with a solenoid valve that can be turned on and off automatically.

Embodiment Hereinafter, the present invention will be explained with reference to the embodiment shown in FIG. One end of the medium passage 6 is connected by a supply circuit 7, and the other end of the medium passage 5, 6 is connected to the medium tank 1 by a discharge circuit 8, so that the pump 2
The heat medium 10 such as oil or water in the medium tank 1 is transferred to the mold 3 by driving the motor 9.
It is possible to circulate the supply to 4.

Reference numeral 11 denotes a cooling coil set in the medium tank 1. The supply circuit 2 is connected to one end of the cooling coil 11, and the cooling coil 11 is arranged at a plurality of positions having different lengths from the supply circuit 12 side (at equal intervals in the embodiment). Discharge circuits 13, 14, 15 are connected to the discharge circuits 13, 14, 15 by branching from the discharge circuits 13, 14, 15, respectively.
A discharge circuit 19 is connected to 3, 14, and 15. By driving the pump (not shown) provided in the supply circuit 12, the cooling water 20 is circulated and supplied to the cooling coil 11 through the supply circuit 12. The electromagnetic valves 16, 17, and 18 are connected to a controller 24 through lead wires 21, 22, and 23, respectively, and can be opened and closed by on/off operation signals A, B, and C input from the controller 24.

Reference numeral 25 denotes a heater set in the medium tank 1. The heater 25 is connected to the controller 24 by a lead wire 26, and is energized and cut off by the on/off operation signal D input from the controller 24, and is turned on. The heating capacity can be switched in stages according to the signal D.

Reference numeral 27 denotes a temperature sensor set in the medium tank 1. The temperature sensor 27 is connected to the controller 24 by a lead wire 28, and sends an electric signal E to the controller 24 to indicate the temperature of the heat medium 10 in the medium tank 1.
It can be sent as

The controller 24 transmits an on/off operation signal D to the heater 25 in response to the detection signal E from the temperature sensor 27, and performs energization/cutoff operation of the heater 25 or on/off operation of the solenoid valves 16, 17, and 18. It is for the purpose of

Function The present invention has the above configuration, and when cooling the heat medium 10, the power supply to the heater 25 is cut off,
When the solenoid valve 16 is opened and the solenoid valves 17 and 18 are closed, the cooling water 20 flows through the entire length of the cooling coil 11. When the solenoid valve 17 is opened and the solenoid valves 16 and 18 are closed, the cooling water 20 flows through the cooling coil 11 by 2/3. In addition, the solenoid valve 18 is opened, and the solenoid valve 16,1
7 is closed, the cooling water 20 flows through the cooling coil 11 by 1/
Only 3 flows. In this way, the solenoid valves 16, 17, 1
By selectively turning on and off 8, the effective length of the cooling coil 11 can be changed in three stages. Since the cooling performance is approximately proportional to the coil surface area determined by the effective length of the cooling coil 11, the cooling performance can be adjusted by selectively turning on and off the solenoid valves 16, 17, and 18.

Conversely, when heating the heat medium 10, the solenoid valve 1
6, 17, and 18 are closed, and the heater 25 is energized.

Therefore, for example, as a selection mode for the solenoid valves 16, 17, and 18, so that the cooling capacity is balanced with the amount of heat received from the mold, only the solenoid valve 16 is selected at a set value of 80°C or less, and solenoid valve 17 is selected at a set value of 80°C to 100°C. If the controller 24 is set so that only the solenoid valve 18 is opened when the set value is 100° C. or higher, the cooling capacity will be represented by a sawtooth curve (solid line) in FIG.

In other words, in a high set temperature range, the solenoid valve 18
This function opens only the solenoid valve 16 to prevent the cooling capacity from becoming excessively large compared to the amount of heat received, and prevents the hunting phenomenon caused by abnormal rises and falls of the heat medium temperature.In addition, in the low set temperature range, only the solenoid valve 16 opens. By increasing the cooling capacity, the temperature of the heat medium 10 can be quickly controlled.

Effects of the Invention As described above, according to the present invention, the temperature control performance of the heat medium supplied to the mold can be improved despite the simple configuration. Moreover, it can be manufactured at relatively low cost.

[Brief explanation of the drawing]

Figure 1 is a system diagram showing an embodiment of the present invention, Figure 2 is a characteristic curve diagram representing the heating capacity of the present invention,
FIG. 3 is a characteristic curve diagram showing the heating capacity and cooling capacity of a conventional mold temperature control device. 1...Medium tank, 2...Pump, 3, 4...
Mold, 5, 6...Medium passage, 7...Supply circuit, 8
... Discharge circuit, 9 ... Motor, 10 ... Heat medium,
11... Cooling coil, 12... Supply circuit, 13,
14, 15... Discharge circuit, 16, 17, 18...
Solenoid valve, 19...Discharge circuit, 20...Cooling water, 2
1, 22, 23, 26, 28...Lead wire, 24
... Controller, 25 ... Heater, 27 ... Temperature sensor.

Claims (1)

[Scope of utility model registration request] A mold temperature control device in which a heat exchanger consisting of a cooler and a heater is installed in a medium tank installed in a mold temperature control circuit, and the heat exchanger is controlled by a controller according to a set temperature range. A supply circuit is connected to one end of the cooling coil constituting the cooler, and a discharge circuit is connected to each discharge circuit by branching from a plurality of positions having different lengths from the supply circuit side of the cooling coil. , a mold temperature control device characterized by being provided with a solenoid valve that can be selectively turned on and off.