JP2006205220A - Apparatus for preheating die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for preheating a die with which the die for forging/casting can be preheated into the temperature distribution becoming a balancing state by repeating a product forming cycle. <P>SOLUTION: A heater supporting member 24 has a shape being fitted into a product forming part 22 of the die 20. In the heater supporting member, a plurality of heaters 26a-26e and supporting part side temperature sensors 28a-28d, are set. The respective heaters 26a-26e are controlled with a heater control unit 34 so as to match to the die temperature at the position of the supporting part side temperature sensors 28a-28d when the temperature distribution in the inner part of the die becomes the balancing state at the repeating time of the product forming cycle. Therein, since the heater supporting member having the plurality of heaters, heats the die under state fit into the product forming part in the die, the state of heat diffusion into the die from the product at the forming time, is easily exhibited again. Therefore, the die can be preheated under the same state as the stationary temperature distribution in the inner part of the die produced with the heat conduction between the product at forming time and the die. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a die preheating device, particularly a die used for forging or casting.

  When forming an article by forging or casting, it is necessary to preheat the mold in advance in order to form an accurate article. This is because when the mold is cold, the material in contact with the mold is cooled and molding is not performed well.

  2. Description of the Related Art Conventionally, in order to preheat a mold, a technique for preheating a mold by forming several products with a cold mold is known. By forming some products using an actual product forming apparatus (forging apparatus or casting apparatus), preheating is performed until the temperature distribution of the mold reaches an equilibrium state. According to this technique, a product molded before the mold is preheated has low molding accuracy and is discarded as a defective product. This is a technique called “discard”. In this technique, waste is generated in the number of defective products to be discarded.

  In order to solve this problem, the technique of Patent Document 1 has been proposed. In this technique, a high frequency induction heating coil is brought into close contact with the outer surface of the mold, and the mold can be preheated in advance by this heating coil.

Japanese Patent Laying-Open No. 2001-113354 (refer to claim 1 and FIG. 1)

  In the technique of Patent Document 1, eddy current can be induced over a wide range up to a deep portion inside the mold by appropriately selecting the frequency of the high-frequency induction heating coil. Therefore, it is possible to heat the inside of the mold. According to the technique of the above-mentioned Patent Document 1, since the mold can be preheated before product molding, there is an advantage that it is not necessary to perform “throwing”.

By the way, the mold has a temperature distribution suitable for molding for each shape. For example, in hot forging, the temperature of the mold becomes high at locations where plastic deformation is significant. In addition, the mold portion corresponding to the end portion of the molded product has a relatively low temperature. Even in casting, the temperature of the mold portion where the molten metal first contacts is high. On the other hand, the mold temperature is lowered at the end portion of the molded product. Also in cold forging, the temperature is high at the site where a large load is applied. In many cases, the mold can be molded satisfactorily by molding with a temperature distribution. However, since the technique of Patent Document 1 heats from the outer surface of the mold, it is difficult to make the temperature distribution of the mold close to when the product molding cycle is repeated. If the temperature distribution during preheating is different from the temperature distribution when the product molding cycle is repeated, molding may not be performed properly.
An object of the present invention is to provide a mold preheating apparatus capable of preheating a mold temperature distribution to a temperature distribution when a product molding cycle is repeated.

  A mold preheating apparatus according to a first aspect of the present invention is directed to a heater support component fitted into a product molding portion of the mold, a plurality of heaters attached to the heater support component, and a mold having a predetermined temperature distribution. It has a technical feature of having a heater controller that controls a plurality of heaters. Here, the product molding part of the mold means a hollow part shaped like a product shape to be molded. Moreover, in casting, the part which comprises the shape of the cavity which inject | pours a molten metal is said. The predetermined temperature distribution is a temperature distribution of a mold that is in an equilibrium state by repeating a product molding cycle in a steady (continuous) manner (hereinafter referred to as a steady temperature distribution), that is, suitable for product production. A concept that includes the temperature distribution of the mold.

  The characteristic point of the present invention resides in that a heater support component having a plurality of heaters is configured to be fitted into a product molding portion of a mold. That is, the heater support part has a shape similar to the product after molding. By appropriately controlling each of the plurality of heaters provided in this heater support component independently, it becomes easy to reproduce the state of thermal diffusion from the product during molding to the mold. Therefore, the mold can be preheated to the same state as the steady temperature distribution of the mold caused by heat conduction between the product and the mold during molding. Here, “the same state as the steady temperature distribution of the mold” includes not only exactly the same but also a state close to approximation. Specifically, it means that it is within a fluctuation range of a steady temperature distribution of a mold suitable for product molding obtained by experiment or measurement at the time of product molding. Moreover, even if it is in an equilibrium state, the temperature distribution of the mold changes during the molding process. The above fluctuation range includes a range where the temperature distribution of the mold generated in the molding process changes.

  According to the present invention, since the mold can be preheated so as to have a temperature distribution equivalent to the steady temperature distribution of the mold when the product molding cycle is repeated, a good product immediately after the start of product molding using the mold Molding becomes possible. In addition, since the heater support part with the heater attached has the same shape as the molded product, the same preheating state can be reproduced using the same heater support part when the same mold is used repeatedly. is there.

  Here, the heater is preferably attached to the heater support component so as to be in contact with the surface of the product forming portion. Thereby, the surface of a product shaping | molding part can be heated directly, and a heating efficiency improves. Further, when the temperature of the heater is controlled, the result of the temperature control is directly reflected on the mold, and the temperature adjustment of the mold becomes easier.

  The first temperature detector is preferably attached to the heater support component. The heater controller controls the heater so that the temperature detected by the first temperature detector becomes a predetermined temperature. More preferably, a plurality of first temperature detectors are provided. Moreover, it is preferable that the 1st temperature detector is attached so that the product molding part surface of a metal mold | die may be touched.

  The temperature of the heater support component can be detected by the first temperature detector. In addition, when the first temperature detector is attached so as to be in contact with the product molding portion, the temperature of the product molding portion surface can be detected. When the temperature of the heater support component can be detected, by feedback control of the heater controller so that the temperature detected by the first temperature detector is the same temperature as the product at the time of molding (predetermined temperature), It is possible to reliably preheat the mold to a steady temperature distribution during repeated product molding cycles. When the first temperature detector is attached so as to be in contact with the product molding part, the temperature detected by the first temperature detector is the temperature at a specific position on the surface of the product molding part. Therefore, the heater controller is feedback-controlled so that the temperature detected by the first temperature detector matches the temperature (predetermined temperature) at the specific position when the mold has a steady temperature distribution. Thus, it is possible to make the mold have a steady temperature distribution when the product molding cycle is repeated more reliably. Furthermore, there exists an advantage that a normal metal mold | die can be used for a metal mold | die by attaching a temperature detector to a heater support member.

  The second temperature detector is preferably attached to the mold. The heater controller controls the heater so that the temperature detected by the second temperature detector becomes a predetermined temperature. More preferably, a plurality of second temperature detectors are provided. The second temperature detector is attached inside the mold or around the mold.

  By measuring the temperature on the mold side, the actual mold temperature can be detected more accurately. Further, the temperature detected by the second temperature detector is a temperature at a specific position of the mold. Therefore, the heater controller is feedback-controlled so that the temperature detected by the second temperature detector matches the temperature at the specific position (predetermined temperature) when the mold has a steady temperature distribution. Thus, the mold can be preheated more reliably to a steady temperature distribution when the product molding cycle is repeated. Furthermore, if a plurality of second temperature detectors are provided, the temperature distribution of the mold can be preheated more reliably to a steady temperature distribution at the time of repeated product molding cycles.

  By using the first and second temperature detectors to feedback control the heater with a heater controller so that the predetermined temperature is reached, the mold is more reliably provided with a steady temperature distribution. Can be preheated.

As described above, the heater controller preferably controls the heater so that the temperature distribution inside the mold becomes a predetermined temperature distribution, that is, a steady temperature distribution inside the mold when the product molding cycle is repeated.
If the mold can be preheated so as to have a steady temperature distribution during product manufacture up to the inside of the mold, a good product can be molded immediately after the start of production.

  The heater is preferably a high frequency heater. The high frequency heater can change the state of the eddy current inside the mold by changing the frequency. As a result, it becomes easy to adjust the heating state inside the mold, and it becomes easy to preheat to a predetermined temperature distribution.

  The heater support component is preferably separable into a plurality of components. “Dividable” means that it can be combined with another component. Thereby, it is not necessary to prepare a dedicated heater support component for each of a plurality of dies having different product molding portions of the dies. This is because a heater support component suitable for each mold can be configured by appropriately combining the divided heater support components.

  ADVANTAGE OF THE INVENTION According to this invention, the apparatus which preheats a metal mold | die to the steady temperature distribution of a metal mold | die at the time of repeating a product molding cycle can be provided.

The main features of the examples are listed.
(1st form) A heater controller controls a some heater independently so that it may become a predetermined heating pattern.
(2nd form) The steady temperature distribution of the metal mold | die at the time of repeating a product molding cycle can be estimated by the estimation means of metal mold | die temperature distribution, such as experiment and heat conduction simulation.
(Third embodiment) The heating pattern of the heater that gives an estimated steady-state temperature distribution is the mold temperature distribution based on temperature measurements or heat conduction simulations during repeated experiments and actual product molding cycles. Can be determined by means for determining a heating pattern that reproduces.
(4th form) If the steady temperature distribution of a metal mold | die can be estimated, the correlation with the steady temperature distribution of a metal mold | die and the temperature of the 1st and / or 2nd temperature sensor attachment position can be calculated | required. The heater is feedback-controlled by the heater control means so that the temperature of the first and / or second temperature sensor becomes the temperature (predetermined temperature) obtained by the above correlation, so that the mold has a steady temperature distribution. Can be preheated.
(5th form) It preheats so that the temperature distribution of the product molding surface of a metal mold | die may become the temperature distribution (predetermined temperature distribution) at the time of a product formation cycle repetition. It is also preferable to preheat so that the temperature distribution inside the mold becomes a temperature distribution (predetermined temperature distribution) when the product formation cycle is repeated.

Embodiments will be described in detail below with reference to the drawings.
<Example 1> In FIG. 1, the typical sectional drawing of the metal mold | die preheating apparatus 10 which concerns on Example 1 is shown. The heater support component 24 has a shape that fits into the product molding portion 22 of the mold 20. A plurality of heaters 26a, 26b, 26c, 26d, and 26e and support component side temperature sensors (first temperature detectors) 28a, 28b, 28c, and 28d are installed in the heater support component. The heaters 26a to 26e and the support component side temperature sensors 28a to 28d are installed on the surface of the heater support component. Therefore, when the heater support component 24 is fitted into the product molding portion 22 of the mold 20, the heaters 26 a to 26 e and the support component side temperature sensors 28 a to 28 d come into contact with the surface 36 of the product molding portion 22. . A mold side temperature sensor 38 (second temperature detector) is embedded in the mold 20. The heater 26 e is electrically connected to the heater controller 34 through the connection line 30. Other heaters are similarly connected to the heater controller 34. The support component side temperature sensor 28 a is electrically connected to the heater controller 34 through the connection line 32. The other supporting component side temperature sensors are also connected to the heater controller 34 in the same manner. The mold side temperature sensor 38 is also electrically connected to the heater controller 34 via the connection line 40. An electric heater or a high frequency heater can be used as the heater. Moreover, a thermocouple etc. can be used for a temperature sensor.

  In FIG. 1, the heater support component 24 has a shape that fits into the product molding portion 22 of the mold 20, but the inside is hollow. This is for facilitating the electrical connection between the heater 26a or the support component side temperature sensor 28a and the heater controller 34. The inside of the heater support component 24 may not be a cavity. Further, the heater support component fitted on the product molding surface of the mold does not need to be similar in shape to the product at the time of molding. The outer shape of the plurality of heaters attached to the heater support component only needs to correspond to any part of the shape of the molded product. Therefore, the heater support component may be any structure that can support the heater so that it contacts the product molding surface in the same manner as the molded product. The heater support component 24 itself is preferably made of a ceramic material. It is because it is excellent in heat resistance and heat insulation.

  Next, the temperature distribution of the mold during product molding will be described. Assume that the mold 20 is a hot forging mold. In hot forging, a material (not shown) heated to a high temperature is inserted into the mold 20 and is weighted from above, and the material is plastically deformed. Finally, a product having a shape that matches the shape of the product forming portion 22 is formed. When this product molding cycle is repeated, the temperature distribution of the mold becomes an equilibrium state (steady temperature distribution). For example, when a high-temperature raw material is first in contact with a portion indicated by B in FIG. 1 (point B), the temperature of the point B becomes high and gradually decreases as the point B moves away from the point B inside the mold. Further, at the point indicated by A in FIG. 1 (point A), the material is greatly plastically deformed so as to spread outward, so the point A becomes high temperature, and the temperature gradually decreases as the distance from the point A increases. As a result, a specific temperature distribution is generated inside the mold. This temperature distribution is determined by conditions such as the shape of the product molding surface 22, the material and temperature of the material, and the load when the material is plastically deformed.

  The actual temperature distribution of the mold during actual product molding should be measured using, for example, an experimental mold with many temperature sensors attached to the mold, or estimated by heat conduction computer simulation. Can be obtained in advance. Furthermore, the temperature distribution of the product molding surface can be estimated by measuring the temperature of each part of the material immediately before molding and the product immediately after molding. If the mold can be preheated to the steady temperature distribution thus obtained, a good product can be formed immediately after the start of product production using the preheated mold.

  By repeating the above experiment or heat conduction computer simulation under different conditions, between the steady temperature distribution of the mold and the temperature at several locations on the molded product surface (ie, the surface of the molded product molded part) Or the correlation between the steady temperature distribution of the mold and the temperature of each part of the mold. Further, the mounting position of the support component side temperature sensor and / or the mold side temperature sensor is known in advance. Therefore, it is possible to determine a set value of the temperature detected by the support part side temperature sensor and / or the mold side temperature sensor for obtaining a steady temperature distribution when the mold is repeated in the product molding cycle. As shown in FIG. 1, when the mold side temperature sensor is embedded in the mold, the temperature distribution in the mold can be accurately estimated. Means for estimating the steady temperature distribution of the mold and the above correlation will be referred to as mold temperature distribution estimation means.

  Next, FIG. 2 illustrates an operation of changing the temperature distribution inside the mold 20 to a predetermined temperature distribution by the mold preheating apparatus of the first embodiment. FIG. 2 shows a state where the heater support component 24 is inserted into the product molding portion 22 of the mold 20. Then, based on the mold temperature distribution estimation means described above, the heaters 26a to 26a are used so that the values of the supporting part side temperature sensors 28a to 28d and / or the detection value of the mold side temperature sensor 38 become the set values (predetermined temperatures). 26e is feedback-controlled. As a result, the inside of the mold can be preheated to a temperature distribution close to a steady temperature distribution when the product molding cycle is repeated. In FIG. 2, the isotherm inside the mold after preheating is schematically shown by reference numeral 44. In the figure, the isotherm indicated by a thick line represents a high temperature, and the thinner the line, the lower the temperature. The temperature distribution is reproduced so that the temperature is high in the vicinity of point A and point B, and the temperature decreases as the distance from each point increases. In FIG. 2, only the heater 26a to 26e shown in FIG. 1 is shown as a representative, and only the support component side temperature sensors 28a to 28d are shown as 28a. Although FIG. 1 shows a schematic cross-sectional view, the mold forming surface may have any three-dimensional shape. The steady temperature distribution of the mold shown in FIG. 2 is merely an example, and the temperature distribution at which a product can be molded satisfactorily varies depending on the conditions at the time of product molding.

  Here, when the mold 20 is preheated, the heater support component 24 is in the same state as when the molded product is fitted into the mold 20. And since the some heater 26a-26e is arrange | positioned at the molded product which touches the surface 36 of the product molding part 22 of a metal mold | die, heat is transmitted from the product to the metal mold | die 20 at the time of an actual product molding, and a metal mold | die is steady. It becomes easy to reproduce the state of temperature distribution.

Next, a heater control pattern by the heater controller will be described. A plurality of heaters are tested in various heating patterns using a mold preheating apparatus of the present embodiment and a mold in which a temperature sensor is embedded. Then, a heating pattern that reproduces the steady temperature distribution of the mold estimated by the mold temperature distribution estimation means described above can be determined.
Further, the set values of the support component side temperature sensor and / or the mold side temperature sensor for making the mold have a steady temperature distribution by the above-described mold temperature distribution estimating means are clarified. Therefore, it is possible to determine the heating pattern of each heater for setting the values of the support component side temperature sensor and / or the mold side temperature sensor as the set values by performing the same test as described above. Thereby, the control pattern of each heater which reproduces the steady temperature distribution of a metal mold | die can be determined. Alternatively, a similar heating pattern of each heater can be determined by heat conduction computer simulation. If the detected value of the temperature sensor on the support component side in contact with the product molding surface of the mold becomes the above set value, the temperature distribution on the product molding surface can be made the temperature distribution when the product molding cycle is repeated. If it does so, a metal mold | die can be made into the steady temperature distribution at the time of a product molding cycle repetition including the temperature distribution inside a metal mold | die from the said correlation. An apparatus for determining the control pattern of each heater that reproduces the steady temperature distribution of the mold will be referred to as mold temperature distribution reproduction heating pattern determination means.

  The reason why the steady temperature distribution of the mold can be reproduced here is that the heater support part fitted in the product molding section includes a plurality of heaters and can be controlled independently. This is because a plurality of temperature distributions can be generated in the mold because a plurality of parts of the product forming part can be heated independently.

  If each heater is controlled by the heater controller so as to have the determined heating pattern, it is possible to reproduce a steady temperature distribution inside the mold as exemplified by reference numeral 44 in FIG. At this time, feedback control of the heater is performed using the detection value of the support component side / mold side temperature sensor, so that it can be preheated to a steady temperature distribution inside the mold as estimated.

  In addition, when experimental data or heat conduction simulation technology is used, it is known that the mold has a predetermined temperature distribution by operating the heater at a predetermined temperature for a predetermined time (by operating with a predetermined heating pattern) Alternatively, the heater may be controlled so as to obtain a predetermined heating pattern. In this case, it is possible to preheat the mold to have a steady temperature distribution without using a temperature sensor (that is, without feedback control).

  In addition, since the heating pattern reproduces the temperature distribution inside the mold during steady product molding, the heater controller does not necessarily need to reproduce the temperature pattern of the product surface during product molding. That is, as a heating pattern, the mold is first heated at a temperature higher than that at the time of product molding, and the mold is preheated to a certain degree in a short time. Thereafter, the temperature of each heater may be appropriately adjusted so that the mold has a predetermined temperature distribution. Thereby, a metal mold | die can be preheated in a short time.

  In addition, it is suitable to use the high frequency heater which can change the heating state inside a metal mold | die by changing a frequency as a heater.

<Example 2> Next, Example 2 is demonstrated using FIG. 3 and FIG. The overall shape of the heater support component 24 is the same as that of the first embodiment. However, in Example 2, it is comprised so that it can divide | segment into the heater support component upper part 24a and the heater support component lower part 24b by the dashed-two dotted line C shown in FIG. The heater support component lower portion 24b can be replaced with a heater support component lower portion 50 of another shape as indicated by an arrow D. Similarly to the heater support part lower part 24b, the heaters 52a, 52b, 52c and the support part side temperature sensors 54a, 54b are also attached to the heater support part lower part 50 of other shapes. In addition, the attachment position of a heater and a temperature sensor may not be the same as the heater support component lower part 24b.
By combining the heater support component upper portion 24a with the heater support component lower portion 50 of another shape, it can be applied to a mold 60 different from the first embodiment shown in FIG. FIG. 4 shows a mold 60 having a product molding portion having a shape different from that of the mold 20 of the first embodiment, a heater support component lower portion 50 of another shape on the upper portion 24a of the heater support component 24 shown in the first embodiment. The state which fitted the heater support component which combined these to the metal mold | die 60 is shown.
That is, in Example 2, since it is not necessary to prepare a dedicated heater support component for each different mold, it is possible to efficiently configure the heater support component.

  Although the case where the number of molds is one in both the first and second embodiments is illustrated, the present invention can also be applied to a case where the mold is divided into a plurality of molds. It can also be applied to hot / warm forging dies, cold forging dies or casting dies. Even in the cold forging, the temperature is increased and the temperature is distributed at the place where the load is applied in the product forming part of the mold. Therefore, the present invention can be applied to a forging die or a casting die regardless of whether it is hot, warm or cold as long as the die requires preheating.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

It is typical sectional drawing explaining the metal mold | die preheating apparatus of Example 1. FIG. It is a figure explaining the state of the temperature distribution inside the metal mold | die preheated with a metal mold | die preheating apparatus. It is a figure explaining the heater support component in the metal mold | die preheating apparatus of Example 2. FIG. It is a figure which shows the state which fitted the metal mold | die preheating apparatus of Example 2 to the metal mold | die.

Explanation of symbols

10: Mold preheating device 20: Mold 22: Product molding part 24: Heater support part 24a: Heater support part upper part 24b: Heater support part lower part 26a, 26b, 26c, 26d, 26e: Heater 28a, 28b , 28c, 28d: Support component side temperature sensor (first temperature detector)
34: Heater controller 36: Surface 38 of the product molding part: Mold side temperature sensor (second temperature detector)
44: Isotherm representing temperature distribution in the mold 50: Heater support part lower part 60 of another shape: Mold of another shape

Claims (7)

A heater support part to be fitted into the product molding part of the mold,
A plurality of heaters attached to the heater support component;
A heater controller for controlling the plurality of heaters so that the mold has a predetermined temperature distribution;
A mold preheating apparatus characterized by comprising:   2. The mold preheating apparatus according to claim 1, wherein the heater is attached to the heater support component so as to be in contact with the surface of the product molding portion. A first temperature detector attached to the heater support component;
The mold preheating device according to claim 1 or 2, wherein the heater controller controls the heater so that a temperature detected by the first temperature detector becomes a predetermined temperature. . A second temperature detector attached to the mold;
4. The heater according to claim 1, wherein the heater controller controls the heater so that a temperature detected by the second temperature detector becomes a predetermined temperature. 5. Mold preheating equipment.   The mold preheating according to any one of claims 1 to 4, wherein the heater controller controls the heater so that a temperature distribution inside the mold has a predetermined temperature distribution. apparatus.   The mold preheating device according to any one of claims 1 to 5, wherein the heater is a high-frequency heater.   The mold preheating device according to any one of claims 1 to 6, wherein the heater support component can be divided into a plurality of components.

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