JP2016030273A - Press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost press device capable of cooling a mold efficiently.SOLUTION: First and second annular cooling bodies 7 and 8 having flow passages 7a and 8a, in which water can flow, are so mounted that they individually contact over the whole areas of the outer circumferences of an upper die 6 and a lower die 5. To the first and second annular cooing bodies 7 and 8, there is connected a pump 12 for circulating water in the flow passages 7a and 8a to perform heat exchange with a mold 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a press apparatus that obtains a molded body by press-molding a heated steel sheet by a mold closing operation of the mold, and cools and quenches the molded body by maintaining the mold closed state.

  In the recent automobile industry, a lightweight and highly safe vehicle body structure is required. In response to this requirement, a press-molded product constituting the vehicle body is molded by a hot press method or the like.

  For example, the press apparatus of Patent Document 1 obtains a press-molded product by a hot press method, and includes a die composed of an upper die and a lower die arranged to face each other, and places a heated steel plate on the lower die. In addition, press molding is performed by lowering the upper die, and the press-molded product obtained by press molding is cooled and quenched by maintaining the closed state of the upper die and the lower die.

  By the way, in order to quench the press-molded product, it is necessary to set the temperature of the mold before press molding to a set value T or less.

  However, when the press apparatus as described above repeatedly press-molds a press-molded product, the next press-molding is performed before the heat of the mold cools down. The mold temperature before press molding, which is repeatedly performed by gradually accumulating, gradually increases, and as a result, the mold temperature before press molding exceeds the set value T.

  In order to avoid this, for example, it is conceivable to perform a hot press method using a mold as disclosed in Patent Document 2. In this mold, a plurality of flow passages through which fluid can flow is formed, and a low temperature fluid is circulated through each of the flow paths to cool the mold, thereby suppressing an increase in mold temperature. .

JP 2013-202619 A JP 2011-206918 A

  However, the mold of Patent Document 2 can be assembled by stacking up and down a plurality of sheet steel materials each cut out at a location corresponding to each of the flow paths, and efficiently cools the mold. However, the manufacturing of the mold is complicated and the manufacturing cost increases.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the low-cost press apparatus which can cool a metal mold | die efficiently.

  In order to achieve the above object, the present invention is characterized in that a cooling body is provided around the mold.

  Specifically, it is intended for a press apparatus that obtains a molded body by press-molding a heated steel plate by a mold closing operation of the mold and cools and quenches the molded body by maintaining the mold closed state. The following solutions were taken.

  That is, in the first aspect of the invention, the cooling body having a flow passage through which fluid can flow is attached to the outer peripheral surface of the mold so as to be in contact with the entire or partial region of the outer peripheral surface of the mold. The cooling body is connected to a fluid circulating means for cooling the mold by circulating a low-temperature fluid through the flow passage and exchanging heat with the mold.

  According to a second invention, in the first invention, the temperature measuring means capable of measuring the temperature of the mold, the temperature measuring means and the fluid circulating means connected to the measured value by the temperature measuring means or the measured value. Control means for outputting an operation signal to the fluid circulation means and starting circulation of the fluid in the flow passage when the calculated value calculated based on the value exceeds a preset stored value. And

  According to a third invention, in the first or second invention, the portion of the cooling body in contact with the mold is made of an aluminum alloy material or a copper material.

  According to a fourth invention, in any one of the first to third inventions, a plurality of cooling fins extending along the fluid flow direction in the flow passage are projected from the inner peripheral surface of the cooling body. It is characterized by being.

  According to a fifth invention, in any one of the first to fourth inventions, a plurality of recesses are formed in the outer peripheral surface of the mold, and the cooling body is fitted into the recesses. A plurality of joint protrusions are provided.

  In the first invention, at the time of press forming, the heat accumulated by moving from the heated steel sheet to the mold is transferred to the low-temperature fluid flowing through the inside of the cooling body, so that the mold is cooled efficiently. The mold temperature before press molding does not become high. Moreover, since the structure of a metal mold | die does not become complicated like patent document 2, manufacturing cost can be restrained low.

  In the second aspect of the invention, the mold cooling operation is performed when the mold temperature is high, whereas the mold cooling operation is not performed when the mold temperature is low, so that the operation time of the fluid circulation means is minimized. This can suppress the driving load of the equipment.

  In the third invention, since the thermal conductivity of the portion of the cooling body in contact with the mold is increased, the heat accumulated in the mold is efficiently moved toward the low-temperature fluid flowing through the flow passage inside the cooling body. Thus, the heat exchange rate between the mold and the low-temperature fluid can be increased.

  In the fourth invention, since the surface area of the inner surface of the flow passage is increased, the heat of the mold is more easily transferred to the low-temperature fluid flowing through the flow passage. Therefore, the heat exchange rate between the mold and the low-temperature fluid is increased, and the mold can be efficiently cooled.

  In the fifth invention, since the contact area between the mold and the cooling body is increased, the movement of the heat accumulated in the mold with respect to the low-temperature fluid flowing through the flow path is further facilitated. Therefore, the heat exchange rate between the mold and the low-temperature fluid is further increased, and the mold can be cooled more efficiently.

1 is a press device according to an embodiment of the present invention. It is sectional drawing in the AA of FIG. FIG. 2 is a diagram showing a state immediately after a press-formed product is obtained by press forming by lowering an elevator base and closing a mold from the state of FIG. 1. It is a figure which shows the state immediately after a raising / lowering stand raises and the metal mold | die opens from the state of FIG. It is the data which shows the relationship between the frequency | count of performing the press molding by the hot press construction method continuously, and the die temperature before each press molding in each of the press apparatus which concerns on embodiment of this invention, and the conventional press apparatus. (A) is a perspective view of a press-molded product in which a measurement point is marked, (b) is a cross-sectional view taken along line BB of (a), and (c) is a press device according to an embodiment of the present invention. It is a figure which shows the result of having investigated hardness and tensile strength in the measurement location of (a), (b) in the press-molded article obtained by press-molding using the conventional press apparatus, respectively.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  1 to 4 show a press apparatus 1 according to an embodiment of the present invention. The press apparatus 1 is for performing press forming called a so-called hot press method, and is configured to form a press-formed product P (formed body) having a cross-sectional hat shape from a heated steel plate 10. A base 2 installed on the floor surface F, a lifting base 3 disposed so as to be able to be lifted and lowered by control of a servo motor (not shown) above the base 2, and a gold for press-molding the press-formed product P A mold 4 is provided.

  The press-formed product P includes a flat top portion P1, a pair of standing wall portions P2 extending in the ascending / descending direction of the lifting platform 3 from both long side edges of the top portion P1, and the standing wall portions. And a pair of flange portions P3 extending outward from the opposite edge of the top portion P1 of P2.

  A die cushion 2a is built in the center of the base 2, and a plurality of lift pin holes 2b that open to the upper surface and extend to the die cushion 2a are formed through the center upper portion of the base 2. Yes.

  The mold 4 includes an upper die 5 having a substantially rectangular parallelepiped shape fixed to the center of the lower surface of the elevator 3 and a lower die 6 having a substantially rectangular parallelepiped shape placed on the center of the upper surface of the base 2. .

  On the lower surface of the center of the upper mold 5, a ridge portion 51 protrudes downward. The ridge portion 51 has a convex molding surface corresponding to the back side of the top portion P <b> 1 and the pair of standing wall portions P <b> 2. 51a is formed.

  A flat back side pressing surface 52 that presses the back side of each flange portion P3 of the press-formed product P in the mold closed state is formed on the lower surface of the upper mold 5 except for the protrusion 51. .

  A plurality of fitting recesses 54 are arranged in parallel in the extending direction of the protrusion 51 on a pair of outer surfaces extending along the extending direction of the protrusion 51 in the upper mold 5 ( (See FIG. 2).

  Further, a plurality of optical fiber type radiation thermometers 11 (temperature measuring means) are embedded in the upper mold 5 so that the temperature of the upper mold 5 can be measured by the radiation thermometer 11.

  A rectangular frame-shaped aluminum alloy first annular cooling body 7 surrounding the upper mold 5 is disposed around the upper mold 5, and the first annular cooling body 7 is formed on the outer peripheral surface of the upper mold 5. It is attached so as to contact over the entire area.

  The cross section of the first annular cooling body 7 has a vertically long rectangular frame shape, and a flow passage 7a through which water (low temperature fluid) can flow is formed.

  At one of the four corners of the first annular cooling body 7, an inflow hole 7c for allowing water to flow into the flow path 7a and an outflow hole 7d for discharging water from the flow path 7a are provided in parallel. (See FIG. 2).

  In addition, an annular cooling fin 7b that protrudes toward the anti-upper die 5 and extends along the direction of water flow in the flow passage 7a is vertically specified at a portion of the first annular cooling body 7 that is in contact with the upper die 5. A pair is provided with an interval of.

  Further, a plurality of fitting protrusions 7 e that fit into the fitting recesses 54 are provided on the first annular cooling body 7 in contact with the upper mold 5.

  A housing recess 6a that opens upward is formed in the center of the upper surface of the lower mold 6 so that the upper half of the housing recess 6a is located outside the lower half of the housing recess 6a.

  In the receiving recess 6a, a holder mold 60 corresponding to the space inside the lower half of the receiving recess 6a is disposed so as to be able to move up and down, and the upper surface thereof is the steel plate when the lifting platform 3 is lowered. The surface of the central portion of 10 is held by the convex molding surface 51a.

  In addition, a flat surface side pressing surface 6c that presses the surface side of each flange portion P3 of the press-formed product P in a mold-closed state is formed on the upper surface of the lower mold 6 except for the housing recess 6a. Yes.

  A lower mold pin hole 6b is formed in the lower part of the lower mold 6 so as to open to a position corresponding to each of the lifting platform pin holes 3b and extend to the receiving recess 6a, and the corresponding lifting platform pin holes 3b and A cushion pin 61 is fitted into the lower mold pin hole 6b so as to be slidable in the vertical direction.

  The cushion pins 61 are interposed between the holder mold 60 and the die cushion 2a, and the holder mold 60 moves up and down by the vertical movement of the cushion pins 61. ing.

  A plurality of the radiation thermometers 11 are embedded in the lower mold 6 and the holder mold 60 so that the temperatures of the lower mold 6 and the holder mold 60 can be measured by the radiation thermometer 11.

  Around the lower mold 6, a second annular cooling body 8 made of an aluminum alloy having a rectangular frame shape surrounding the lower mold 6 is disposed. The second annular cooling body 8 is an outer peripheral surface of the lower mold 6. It is attached so that it may contact over the whole area.

  The cross section of the second annular cooling body 8 has a vertically long rectangular frame shape, and a flow passage 8a through which water can flow is formed.

  The second annular cooling body 8 is provided with an inflow hole and an outflow hole (not shown) that allow water to flow into and out of the flow passage 8a, similarly to the first annular cooling body 7.

  An annular cooling fin 8b that protrudes toward the anti-upper die 5 and extends along the direction of water flow in the flow passage 8a is vertically specified at a portion of the second annular cooling body 8 that contacts the upper die 5. A pair is provided with an interval of.

  In the inflow hole 7c and the outflow hole 7d of the first annular cooling body 7, a pump 12 (which cools the upper mold 5 by circulating water through the flow path 7a and exchanging heat with the upper mold 5) Fluid circulation means) is connected.

  The pump 12 is also connected to an inflow hole and an outflow hole (not shown) of the second annular cooling body 8, and heat is generated between the water circulating through the flow passage 8 a by the pump 12 and the lower mold 6. The lower mold 6 is cooled by the replacement.

  A control panel 13 (control means) is connected to each of the radiation thermometers 11 and the pump 12, and the control panel 13 exceeds the set value T stored in advance by the measured value of each of the radiation thermometers 11. At this time, an operation signal is output to the pump 12 to start the circulation of water in the first and second annular cooling bodies 7 and 8. The set value T is a temperature at which the die 4 before press molding must be kept below in order for the press-molded product P to be properly quenched.

  Then, the heated steel plate 10 is placed on the lower mold 6, and the elevator 3 is lowered to close the upper mold 5 and the lower mold 6 to obtain the press-formed product P. The press-formed product P is cooled and quenched by maintaining the mold closed state by the mold 4.

  Next, a method for obtaining a press-formed product P by press-forming from the heated steel plate 10 by the hot press method using the press device 1 will be described.

  FIG. 1 shows a state in which a steel plate 10 heated in a heating furnace or the like is carried between an upper die 5 and a lower die 6 in a mold open state. In this state, the holder mold 60 is positioned in the upper half of the housing recess 6a by the upward movement of each cushion pin 61.

  From the state of FIG. 1, the lifting platform 3 is lowered. Then, the convex forming surface 51 a of the ridge portion 51 abuts on the central portion of the steel plate 10 and sandwiches the central portion of the steel plate 10 with the tip surface of the holder mold 60.

  When the elevating table 3 is further lowered, the front side pressing surface 6c causes the outer side portion of the steel plate 10 to move away from the back side pressing surface while the holder mold 60 is gradually retracted downward against the urging force of the die cushion 2a. The end of the steel plate 10 comes into contact with the back-side pressing surface 52 by being pressed and bent toward the 52 side.

  Thereafter, when the elevator 3 is further lowered, as shown in FIG. 3, the outer half portion of the steel plate 10 is bent into a substantially L shape by the upper half portion of the receiving recess 6a and the front side pressing surface 6c. A press-formed product P is obtained by placing the steel plate 10 along the shape-forming surface 51a and the back-side pressing surface 52.

  Thereafter, the upper mold 5 and the lower mold 6 are kept in the mold closed state, and the press-molded product P is cooled by holding the press-molded product P under pressure to quench the press-molded product P, and then the quenching is finished. Then, as shown in FIG. 4, the lifting platform 3 is raised so that the convex molding surface 51 a and the back-side pressing surface 52 are separated from the press-molded product P, and the die mold 2 a and each cushion pin 61 are used to hold the holder mold 60. Moves upward and becomes the original position.

  Next, a description will be given of results of experiments in which press forming by the hot press method is continuously performed using the press device 1 according to the embodiment of the present invention and a normal press device.

  FIG. 5 is a graph plotting data obtained by experiments with the horizontal axis representing the number of press moldings performed continuously and the vertical axis representing the temperature of the mold 4 before each press molding.

  Data D1 is data indicating the result of continuous press forming with the press device 1, and the temperature of the mold 4 before each press forming was equal to or lower than the set value T even if the press forming was continuously performed 1480 times. . On the other hand, the data D2 is data indicating the result of continuous press forming with a normal press device, and the temperature of the mold 4 before press forming becomes the set value T just by performing press forming continuously about 30 times. It was a result that exceeded. As described above, by arranging the first and second annular cooling bodies 7 and 8 around the mold 4, it is possible to confirm that the temperature of the mold 4 before press molding does not easily rise even if press molding is continuously performed. It was.

  6 (a) and 6 (b) are diagrams showing measurement points of hardness (Hv) and tensile strength (Mpa) in press-formed products formed by the press device 1 and the conventional press device, respectively. (C) is the figure which showed the result of the hardness and tensile strength of each measurement location of FIG. 6 (a), (b) in the last press molded product press-formed 1480 times continuously. The tensile strength was calculated by an approximate conversion formula (MPa = 3.12 × Hv16) with respect to the Vickers hardness of the steel. In addition, the pass / fail judgment was made such that when the tensile strength was 1300 MPa or more, quenching was performed correctly, and in other cases, quenching was not performed correctly.

  Then, the press-formed product P press-formed by the hot press method using the press device 1 has a higher tensile strength than the press-formed product press-formed by the hot press method using the conventional press device, and is continuously press-formed. It was confirmed that quenching was correctly performed on each press-formed product P even when the test was performed. This is presumably because the temperature of the mold 4 before each press forming was lower than the set value T even if the press forming by the hot press method was continuously performed in the press device 1.

  As described above, according to the embodiment of the present invention, the heat accumulated by moving from the heated steel plate 10 to the mold 4 flows through the first and second annular cooling bodies 7 and 8 during press forming. Since it moves to water, the mold 4 is efficiently cooled and the temperature of the mold 4 before press molding does not become high. Moreover, since the structure of the metal mold | die 4 does not become complicated like patent document 2, manufacturing cost can be restrained low.

  In addition, when the temperature of the mold 4 is increased, the cooling operation of the mold 4 is performed. On the other hand, when the temperature of the mold 4 is low, the cooling operation of the mold 4 is not performed. And the driving load of the press device 1 can be suppressed.

  In addition, since the first and second annular cooling bodies 7 and 8 are made of an aluminum alloy material, the thermal conductivity of the portions of the first and second annular cooling bodies 7 and 8 that are in contact with the mold 4 is high. The heat accumulated in 4 moves efficiently toward the water flowing through the flow passages 7a and 8a in the first and second annular cooling bodies 7 and 8, and the heat between the mold 4 and the water. The exchange rate can be increased.

  Furthermore, since the surface areas of the inner surfaces of the flow passages 7a and 8a are increased by the cooling fins 7b and 8b, the heat of the mold 4 is further easily transferred to the water flowing through the flow passages 7a and 8a. Therefore, the heat exchange rate between the mold 4 and water is increased, and the mold 4 can be efficiently cooled.

  In addition, since the contact area between the mold 4 and the first and second annular cooling bodies 7 and 8 is increased by the fitting protrusions 7e and the fitting recesses 54, the water flowing through the flow passages 7a and 8a is increased. The movement of heat accumulated in the mold with respect to is further facilitated. Therefore, the heat exchange rate between the mold 4 and water is further increased, and the mold 4 can be cooled more efficiently.

  In the press device 1 according to the embodiment of the present invention, water is circulated through the first and second annular cooling bodies 7 and 8 to cool the mold 4. However, the present invention is not limited to this. Oil may be circulated through the second annular cooling bodies 7, 8, and a low temperature fluid may be circulated through the first and second annular cooling bodies 7, 8 to cool the mold 4.

  In the embodiment of the present invention, the first annular cooling body 7 is in contact with the entire outer peripheral surface of the upper mold 5, and the second annular cooling body 8 is in contact with the entire outer peripheral surface of the lower mold 6. However, the present invention is not limited to this, and the first annular cooling body 7 is in contact with the partial region of the upper mold 5 and the second annular cooling body 8 is in contact with the partial region of the lower mold 6. Also good.

  In the embodiment of the present invention, the radiation thermometer 11 is used to measure the temperature of the mold 4, but the temperature of the mold 4 may be measured using another thermometer.

  In the embodiment of the present invention, the first and second annular cooling bodies 7 and 8 are formed of an aluminum alloy material. However, the present invention is not limited to this. For example, the first and second annular cooling bodies 7 and 8 may be formed of a copper material and have high thermal conductivity. What is necessary is just to form using a material. Further, it is not necessary to form all the parts of the first and second annular cooling bodies 7 and 8 with an aluminum alloy material or a copper material, and at least the parts of the first and second annular cooling bodies 7 and 8 that are in contact with the mold 4. May be formed of an aluminum alloy material or a copper material.

  In the embodiment of the present invention, the fitting protrusion 7e and the fitting recess 54 are formed on the upper mold 5 and the first annular cooling body 7, but are formed on the lower mold 6 and the second annular cooling body 8. Also good.

  Further, in the embodiment of the present invention, when the measured value by each radiation thermometer 11 exceeds the preset value T stored in advance, the control panel 13 outputs an operation signal to the pump 12 to output the first and second annular coolings. The circulation of water in the bodies 7 and 8 is started. However, the present invention is not limited to this. For example, the temperature change amount Δt of the mold 4 is calculated every time press forming, and the calculated value Δt is stored in advance. When the set value T ′ is exceeded, the control panel 13 may output the operation signal to the pump 12 to start the water circulation in the first and second annular cooling bodies 7 and 8.

  The present invention is suitable for a press apparatus in which a heated steel plate is press-molded by a mold closing operation to obtain a molded body, and the molded body is cooled and quenched by maintaining the mold closed state. .

DESCRIPTION OF SYMBOLS 1 Press apparatus 4 Mold 7 1st cyclic | annular cooling body 7a, 8a Flow path 7b, 8b Cooling fin 7e Fitting protrusion 8 2nd cyclic | annular cooling body 10 Steel plate 11 Radiation thermometer (temperature measurement means)
12 Pump (fluid circulation means)
13 Control panel (control means)
54 Fitting recess P Press molded product (molded product)

Claims (5)

A press apparatus that obtains a molded body by press-molding a heated steel sheet with a mold closing operation, and cools and quenches the molded body by maintaining the mold closed state,
A cooling body having a flow passage through which fluid can flow is attached to the outer peripheral surface of the mold so as to be in contact with the entire outer peripheral surface or a partial region of the mold,
A press apparatus characterized in that a fluid circulating means for cooling the mold is connected to the cooling body by circulating a low-temperature fluid through the flow passage and exchanging heat with the mold. In the press apparatus of Claim 1,
Temperature measuring means capable of measuring the temperature of the mold,
When the measured value by the temperature measuring means or the calculated value calculated based on the measured value exceeds the preset stored value connected to the temperature measuring means and the fluid circulating means, an operation signal is sent to the fluid circulating means. And a control means for starting fluid circulation in the flow passage. The press device according to claim 1 or 2,
The press unit characterized in that the portion of the cooling body that contacts the mold is made of an aluminum alloy material or a copper material. In the press apparatus as described in any one of Claim 1 to 3,
A press apparatus, wherein a plurality of cooling fins extending along a flow direction of fluid in the flow passage are provided on the inner surface of the flow passage. In the press apparatus as described in any one of Claim 1 to 4,
A plurality of recesses are formed in the outer peripheral surface of the mold,
The cooling device is provided with a plurality of fitting protrusions that are fitted into the respective recesses.

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