JPH0228416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold temperature control device for appropriately controlling the temperature of a mold used in die casting or the like.

[Prior art and its problems] The temperature of molds used for aluminum die casting, zinc die casting, etc. is usually raised using a heating medium such as steam or oil, and the mold is cooled using cooling water. It is carried out by The reason for this is that simply turning on and off the cooling water without using a heating medium provides coarse control units, making it impossible to properly control the temperature of the mold. However, since conventional equipment handles heating medium at a high temperature of 100°C to 300°C, there is a risk of injury such as burns to workers when replacing the mold, and the temperature of the mold increases. In this method, a heating medium is heated, and after the temperature of the mold is raised, the mold is cooled with cooling water, so there is a problem in that energy loss is large, leading to a rise in both initial cost and running cost. Furthermore, when oil is used as the heating medium, the flow path for the heating medium and the flow path for the cooling water must be separate systems, which complicates the equipment and places greater restrictions on the mold itself. There are drawbacks.

In addition, in order to prevent the device configuration from becoming complicated, there are some devices that manually control the cooling water, but in such devices, cooling water control is largely dependent on the intuition of the operator, and as a result, control stability,
There is a problem of lack of reproducibility.

In addition, Japanese Patent Application Laid-open No. 57-97838, Publication No. 46-
Publication No. 2971 discloses that the temperature of the mold can be controlled without using a heating medium by using a temperature controller that detects the mold temperature and issues an opening/closing signal to the solenoid valve, and a solenoid valve installed in the cooling water passage. An apparatus for doing so is disclosed. However, these methods continuously measure the mold temperature along the casting cycle, compare this mold temperature with a preset temperature or a calculated temperature, and issue an opening/closing signal for a solenoid valve to determine the water flow time. It is something to control. Control that continuously measures mold temperature is susceptible to changes in mold temperature. For example, even if the temperature temporarily exceeds the set temperature at the time of measurement, the water flow will stop, resulting in poor mold temperature rise, or if the mold temperature changes due to external factors during the casting cycle. There were also problems such as being directly affected by it. In addition, since it is controlled by water flow time,
This means turning on and off a large amount of cooling water, which is equivalent to fully opening multiple solenoid valves in the present invention, which will be described later, and the thermal conditions of the entire model when water is flowing and when it is stopped are extremely different. In addition to the occurrence of cracks in the mold due to heat shock, it is also difficult to maintain constant mold temperature changes, which poses problems in terms of quality improvement.

Furthermore, JP-A No. 51-105924 discloses that the temperature of the mold during pouring is measured, compared with a preset value, and the temperature of the casting is kept constant from pouring to mold opening. This paper discloses a technology for calculating the time for and controlling the casting cycle based on the result. However, since the curing time is controlled to keep the temperature of the casting itself constant when the casting is taken out, it does not control the mold temperature during casting, so the mold temperature is too high. It is not possible to prevent seizures caused by molding or poor water flow caused by too low a mold temperature.

[Problems to be Solved by the Invention] The present invention provides (a) controlling the mold temperature by controlling the amount of water flow instead of the conventional control of the water flow time, and (b) controlling the mold temperature by controlling the conventional continuous mold temperature. Instead of detection, in one casting cycle, the mold temperature measured at one measurement point is used as the representative mold temperature for that cycle, and (c) the mold temperature can be determined from time to time by combining the above (a) and (b). It is an object of the present invention to provide a mold temperature control device that is less susceptible to momentary changes and less susceptible to changes in mold temperature caused by external factors.

[Means for Solving the Problems] According to the present invention, the above object is achieved by the following mold temperature control device. That is, a temperature detector that detects the temperature of the mold, a solenoid valve installed on the cooling water passage that supplies cooling water to the mold, and a set temperature in which the mold temperature detected by the temperature detector is set in advance. A temperature control device for a mold, comprising: a temperature regulator that controls opening and closing of the solenoid valve to flow a required amount of cooling water determined by comparing the solenoid valve with the temperature regulator; and a plurality of pairs of solenoid valves and temperature regulators are provided, and the solenoid valves are provided in parallel with each other, and the amount of cooling water supplied to the mold is controlled by opening and closing the solenoid valves. (b) The combination of the temperature sensor, the plurality of pairs of solenoid valves, and the temperature regulator is set such that the water flow rate can be increased or decreased in stages from stop to the maximum, (b-1) During one casting cycle, The mold temperature is measured by the temperature detector at one measurement point, and (2) the mold temperature measured at the one measurement point is compared with a preset temperature, and the mold temperature is determined. Determine the amount of cooling water for the first casting cycle so that when the temperature is low, the amount of water flowing is small, when the mold temperature is appropriate, the amount of water flowing is medium, and when the mold temperature is high, the amount of water flowing is large. B-3) The temperature controller controls the opening and closing of the solenoid valve paired with the temperature controller so that the required amount of cooling water is obtained, and the amount of water flowing through the first casting cycle is adjusted. ) The opening/closing state of the electromagnetic valve is fixed until the end of the first casting cycle, and the adjusted water flow rate is kept constant until the end of the first casting cycle, (b-5) The casting cycle time is set in advance. A mold temperature control device characterized in that the temperature control device is related to control, such that when the cycle time is exceeded, all solenoid valves are closed and water flow is stopped.

[Function] In the mold temperature control device of the present invention, the mold temperature measured at one predetermined measurement point in one casting cycle is fixed and used as the representative mold temperature of that casting cycle, A temperature controller compares this with a predetermined set temperature and controls the opening and closing of multiple solenoid valves to keep the optimum amount of water flowing throughout the casting cycle. Even if the mold temperature changes abnormally or due to external factors during the casting cycle, the amount of cooling water supplied is not affected by this, allowing stable mold temperature control. The reason why it is not necessary to continuously measure the mold temperature or change the amount of water continuously during one casting cycle is because the amount of heat added from the molten metal to the mold during one casting cycle is constant. This is because it was thought that the change in mold temperature would be constant, and that by measuring at one point in one cycle, it would be possible to control the mold temperature for the entire cycle.

Furthermore, the mold temperature is controlled not by the water flow time but by the water flow rate, and the water flow rate is controlled by opening and closing a plurality of electromagnetic valves (the water flow rate can be adjusted by a throttle). In other words, in the casting cycle, when the mold temperature is low, the water flow rate is reduced to increase the mold temperature rise, and when the mold temperature is at an appropriate temperature, the water flow rate is set to medium to balance the mold temperature to an appropriate temperature. When the temperature is high, increase the amount of water flow to increase the temperature drop in the mold. With such control, the mold temperature can be corrected to a stable side (appropriate temperature balance state) more quickly, unlike the case where the entire amount is turned on and off. By bringing the temperature closer to the proper temperature balance, it is possible to prevent quality defects such as burning and sink marks caused by too high a mold temperature, and it is also possible to prevent poor water flow caused by too low a mold temperature.

In addition, overcooling can be prevented by stopping cooling when the cycle time is over, and even if the cycle time exceeds due to trouble during the casting cycle, the mold temperature will drop by stopping the cooling water. This prevents mold temperature overcooling from occurring in the next casting cycle.

Furthermore, the present invention raises the mold temperature by simply heating the mold from the molten metal without using a heating medium, and controls the mold only by controlling the amount of cooling water in stages. In addition to being safer than those that use carbon, the initial cost and running cost are lower, contributing to energy and resource savings.

[Example] An example of the present invention will be described below with reference to the drawings.

In FIG. 3, a cooling water intake port 1a of a mold 1 is connected to a cooling water supply source 3 via a cooling water passage 2, and in the cooling water passage 2, solenoid valves V ₁ , V ₂ , ...Vn are connected in parallel with each other. is interposed in. That is, the cooling water passage 2 has a parallel passage section, and one solenoid valve is provided in each passage of the parallel passage section. Solenoid valve V ₁ ,
V ₂ ,...Vn are the respective solenoids SOL ₁ , SOL ₂ ,
...Driven to open and close by SOLn. Cooling water passage 2
Variable throttles O ₁ , O ₂ , ...On are also interposed in series with the solenoid valves V ₁ , V ₂ , ...Vn in each passage of the parallel passage section, and variable throttles O ₁ , O ₂
...On can adjust the amount of cooling water in the passages having the solenoid valves V ₁ , V ₂ ...Vn, respectively.

On the other hand, a temperature detector 4 such as a thermocouple or a resistance temperature detector is attached to the mold 1, and the temperature detector 4 is connected to a temperature controller TH via a converter 5 such as a thermoelectric temperature converter or a resistance temperature converter. ₁ , TH ₂ , ... THn electrically connected. These temperature controllers TH ₁ ,
TH ₂ , ...THn are the respective solenoid valves V ₁ , V ₂ ...Vn
The temperature controller TH ₁ ,
TH ₂ ,...THn and solenoid SOL ₁ , SOL ₂ ,...
SOLn constitutes a control circuit as shown in FIG. 2, for example.

FIG. 2 typically shows a control circuit for the temperature controller THi and the solenoid SOLi. The other temperature controllers and solenoids also constitute a similar control circuit. In Fig. 2, 6, 7, 8, 9 are auxiliary relays, 6a is the b contact of the auxiliary relay 6, 6b is the b contact of the auxiliary relay 6, 7a is the a contact of the auxiliary relay 7, and 8a is the a of the auxiliary relay 8. Contacts 9a and 9a' indicate a contacts of the auxiliary relay 9. And in the same figure,
10 is the condition for determining measurement points P ₁ , P ₂ ,...P ₅ ,
For example, it is a switch that is turned on when conditions such as mold clamping are met, and 11 is a switch that is turned off when the cycle time exceeds a set time.

Next, the control configuration and its effects will be explained.

In FIG. 1, 12 denotes each casting cycle C ₁ ,
The mold temperatures corresponding to C ₂ , C ₃ , and C ₄ are shown, and if one casting cycle C ₂ is taken as an example, this casting cycle C ₂ has a pouring process A ₁ , a curing time A ₂ ,
It consists of a product removal and mold release agent application step _A3 , and a mold clamping step _A4 . And casting cycle C ₂
The measurement point P ₂ is preferably after mold matching and before pouring,
Determined at one measurement point and other casting cycles
Measurement points P ₁ , P ₃ , and P _{4 of C 1 , C 3 , and} C ₄ are also determined at similar points. The measuring point P ₃ also has the significance of being the end point of the casting cycle C ₂ . Further, in FIG. 1, 13 indicates the set temperature of the mold 1.

The mold temperature measured at this measurement point is taken as a constant representative mold temperature throughout that one casting cycle. Since the amount of heat applied from the molten metal to the mold in one cycle is almost constant, the change in mold temperature in each cycle is almost constant, and if you measure the mold temperature at one point in one cycle, you can determine the change in mold temperature. A constant representative mold temperature is used because it is possible to control the mold temperature throughout the cycle. By using a constant representative mold temperature, even if the mold temperature changes due to external factors, it is less affected by the change.

When the temperature of the mold 1 exceeds the set temperature 13, as at measurement time P ₃ of casting cycle C ₃ and measurement time P ₄ of casting cycle C ₄ , the temperature controller THi is turned on in FIG. The contact is turned on and the auxiliary relay 6 is energized. As a result, the a contact 6a of the auxiliary relay 6 is turned on, so at this time, the conditions for determining the mold temperature measurement points P ₃ and P ₄ (for example, conditions for mold clamping, etc.) must be prepared. For example, switch 10 is turned on and auxiliary relay 7 is energized.
When the auxiliary relay 7 is energized, its a contact 7a is turned on, and at this time, if the cycle time has not exceeded, the switch 11 is on, so the auxiliary relay 9 is energized. As a result, the auxiliary relay 9
The a-contact 9a' is turned on, and the a-contact 7a is self-maintained in the on-state, and the other a-contact 9a is turned on, the solenoid SOLi is activated, and the solenoid valve Vi is opened. Therefore, the cooling water flows into the mold 1 via the solenoid valve Vi and the variable throttle Oi. Due to the self-retention of the a-contact 7a, once the cooling water starts flowing, it continues to flow during the casting cycle.

_{Next , the} mold ₁
When the temperature is lower than the set temperature 13, the temperature controller THi energizes the auxiliary relay 6 and turns on its b contact 6b, thereby energizing the auxiliary relay 8. When the auxiliary relay 8 is energized, its b contact (normally closed contact) 8a is turned off, and the auxiliary relay 9 is not energized. Therefore, the a contact 9a of the auxiliary relay 9 is turned off, the solenoid SOLi is not operated, the solenoid valve Vi is closed, and no cooling water is supplied. Therefore, if the mold temperature is below the set temperature 13 at measurement time points P ₁ and P ₂ , the cooling water will not flow and the mold temperature will rise more quickly.

For example, in a casting cycle _C4 in which cooling water is supplied to the mold 1, if the cycle is extended due to some trouble and the next casting cycle measurement point _P5 exceeds a predetermined set cycle time, a switch is activated. 11 is off,
The auxiliary relay 9 is de-energized. Therefore, the a contact 9a is also turned off, and the solenoid SOLi closes the solenoid valve Vi. This stops water flow and
The mold is prevented from overcooling.

The water continues to flow until the end of one casting cycle, and the amount of water flow is determined by the opening and closing of the solenoid valve. The flow rate of this water is controlled in stages by opening and closing multiple solenoid valves whose flow rate is regulated by throttles, from the stop of water flow to the maximum. When this happens, the water flow rate is set to be low (balanced state), and when the mold temperature is high, the water flow rate is determined to be high, so that the mold temperature is corrected to an appropriate temperature more quickly.

[Effects of the Invention] As explained above, according to the mold temperature control device of the present invention, an optimal point in one casting cycle is determined as the measurement point, and the mold temperature at this measurement point is determined as the measurement point. This is regarded as the representative mold temperature of the casting cycle, and the amount of cooling water is controlled based on it, so even if the mold temperature rises or falls abnormally at a point other than the measurement point during the casting cycle, the amount of cooling water cannot be controlled. Not done. Therefore, the mold temperature is less susceptible to moment-to-moment variations or variations due to external factors, and stable mold temperature control can be achieved.

In addition, the mold temperature is controlled by controlling the amount of water flowing, and the amount of water flowing is controlled by the operation of a plurality of solenoid valves installed in parallel with each other and a temperature controller installed in a 1:1 relationship with the solenoid valves. Then, the water flow can be changed stepwise from small to medium to large from the stop to the maximum, so when the mold temperature is low, a large mold temperature rise can be obtained by reducing the water flow amount, and when the mold temperature is suitable, A balanced state can be obtained by increasing the water flow rate, and when the mold temperature is high, a large mold temperature drop can be obtained by increasing the water flow rate, thus allowing the mold temperature to be corrected to a stable side (balance) more quickly in successive casting cycles. . It also prevents quality defects such as seizure and sink marks caused by too high a mold temperature, and also prevents poor hot water flow caused by too low a mold temperature and heat shock caused by a large amount of cooling water turning on and off. can.

In addition, water flow is stopped when the cycle time exceeds the set cycle time, so even if there is some trouble in the previous casting cycle and the cycle time exceeds the set cycle time, unnecessary water will be removed from the mold. It is possible to prevent the mold from dropping and the mold temperature can be raised quickly in the next casting cycle.

Furthermore, the temperature control of the mold according to the present invention is performed by using only cooling water without using a heating medium, so it is extremely safe, reduces running costs and initial costs, and saves energy. It can contribute to resource saving.

Furthermore, since the temperature control of the mold according to the present invention does not use cooling water and a heating medium in combination, the piping system is simplified and the degree of freedom in mold design is greatly increased.

[Brief explanation of drawings]

FIG. 1 is a mold temperature characteristic diagram, FIG. 2 is a control circuit diagram used in the present invention, and FIG. 3 is a schematic side view showing the overall configuration of the present invention. DESCRIPTION OF SYMBOLS 1... Mold, 1a... Cooling water intake, 2... Cooling water passage, 3... Cooling water supply source, 4... Temperature detector, 5... Converter, 6, 7, 8, 9... ...Auxiliary relay, 6a, 6b, 7a, 8a, 9a, 9a'... Contact, TH ₁ , TH ₂ , ... THn... Temperature controller, V ₁ ,
V ₂ ,...Vn...Solenoid valve, SOL ₁ , SOL ₂ ,...SOLn
... Solenoid, O ₁ , O ₂ , ... On ... Variable aperture.

Claims (1)

[Claims] 1. A temperature detector that detects the temperature of the mold, a solenoid valve provided on a cooling water passage that supplies cooling water to the mold, and a temperature sensor that detects the mold temperature detected by the temperature detector in advance. A mold temperature control device comprising: a temperature regulator that controls opening and closing of the solenoid valve to flow a required amount of cooling water determined by comparing it with a set set temperature; (a) the solenoid valve and the temperature; A plurality of pairs of solenoid valves and temperature regulators are provided, and the solenoid valves are provided in parallel with each other, and the amount of cooling water supplied to the mold is controlled by opening and closing of the solenoid valves. (b) The combination of the temperature sensor, the plurality of pairs of electromagnetic valves, and the temperature controller is set to be adjustable in stages from the stop of water flow to the maximum water flow, and (b-1) one casting. During the cycle, the mold temperature is measured by the temperature detector at one measurement point, and (b-2) the mold temperature measured at the one measurement point is compared with a preset temperature, The amount of cooling water in the first casting cycle is adjusted so that when the mold temperature is low, the amount of water flowing is small, when the mold temperature is appropriate, the amount of water passing is medium, and when the mold temperature is high, the amount of water passing is large. (b-3) controlling the opening and closing of the solenoid valve paired with the temperature regulator so as to obtain the required amount of cooling water, and adjusting the amount of water flowing through the first casting cycle; (B-4) The opening/closing state of the solenoid valve is fixed until the end of the first casting cycle, and the adjusted water flow rate is kept constant until the end of the first casting cycle, and (B-5) The casting cycle time is fixed. A temperature control device for a mold, characterized in that the temperature control device is related to control, such that when a preset cycle time is exceeded, all solenoid valves are closed and water flow is stopped.