JP4108620B2 - Hot forging apparatus and hot forging method - Google Patents

Description

  The present invention relates to a hot forging device and a hot forging method characterized by a mechanism for knocking out a molded workpiece from the mold.

  2. Description of the Related Art Conventionally, some hot forging apparatuses are provided with a knockout mechanism for projecting a molded workpiece from the mold. For example, as shown in FIG. 9 (modified reference from FIG. 1 of Patent Document 1), a conventional hot forging apparatus includes a punch 95, a die 913 provided opposite to the punch 95, and a die 931. It has a knockout pin 935 that is combined and movable in the axial direction, and a knockout pin driving means (not shown) that moves the knockout pin 935 via a knockout rod 939 (Patent Document 1).

This hot forging device forms a die by a combination of a punch 95, a die 913, a knockout pin 935, and other components (punch pin 931, sleeve knockout 932, etc.) provided as necessary. The hot forging device presses the workpiece inserted into the mold and molds it into a predetermined shape. The formed workpiece is ejected from the mold by a knockout pin 935.
JP-A-3-2488736

  By the way, hot forging is to perform plastic deformation by heating to a temperature higher than the recrystallization temperature of the material constituting the workpiece, and for steel materials, it is heated to several hundreds of degrees C. to several hundreds of degrees C. (for example, 450.degree. C. or more). . Therefore, the die used in the hot forging device is affected by high heat and the durability is lowered.

  The present invention has been made in view of the above circumstances, and should provide a hot forging device and a hot forging method in which the improvement of the die life is improved by improving the knockout mechanism over the prior art. Let it be an issue.

  As a result of intensive studies aimed at solving the above problems, the present inventors have obtained the following knowledge. Hot forging is often performed in order by a plurality of dies in order. In such a hot forging apparatus, the mold is opened after the work is formed, and the work is gripped and moved from the mold by the conveying means and placed in the next mold or the like. Accordingly, the molded workpiece is held in close contact with the die until the mold is opened and held by the conveying means. That is, it is considered that the amount of heat transferred from the workpiece to the mold increases after the workpiece is molded and is conveyed by the conveying means, which is a cause of a decrease in the mold life.

  Therefore, as a method for improving the die life, the die life is improved by reducing the amount of heat transfer from the workpiece to the die until the workpiece is conveyed or removed by the conveying means after the workpiece is molded. I came up with it. Then, in order to reduce the amount of heat transfer from the workpiece to the mold, attention was paid to the knockout mechanism, and the present invention was completed.

That is, the hot forging device of the present invention that solves the above problems includes a punch, a die provided opposite to the punch, a knockout pin that is combined with the die and movable in the axial direction, the punch, and the die. And a knockout pin driving means for moving the knockout pin in a direction in which the workpiece after hot forging with the knockout pin protrudes from the die,
The knockout pin driving means includes a mechanism for projecting the workpiece after hot forging in a plurality of stages and a mechanism for reducing the contact area by separating the knockout pin from the workpiece for each of a plurality of stages of projecting the workpiece. It is characterized by providing.

That is, the knockout pin divides the workpiece into a plurality of stages, and the amount of heat transfer from the workpiece to the mold can be reduced while holding the workpiece in the mold.
In particular, the amount of heat transfer from the workpiece to the knockout pin can be reduced by reducing the contact area by separating the knockout pin from the workpiece for each protrusion.

  Here, in the conventional hot forging apparatus described in Patent Document 1 and the like, the protrusion of the workpiece by the knockout mechanism is performed in one stage after the forming is completed. In the prior art, the workpiece is ejected by the knockout pin after the workpiece is formed, after the mold is opened, and after the conveying means moves to the vicinity of the workpiece in the mold to receive the workpiece, the workpiece needs to be held in the mold. When it was gone. Therefore, in the present invention, after the workpiece is formed, in order to reduce the amount of heat transfer from the workpiece to the mold until the conveying means moves to receive the workpiece, before the conveying means receives the workpiece, The workpiece was slightly protruded by the knockout pin, and the contact area between the mold and the molded workpiece was reduced in advance. By reducing the contact area, the amount of heat transfer from the workpiece to the mold can be reduced. As a result, it is possible to achieve both improvement of the mold life and retention of the work in the mold. And as a secondary effect by employ | adopting the structure which protrudes a workpiece | work in several steps, the appropriate adhesion | attachment of mold | die lubrication liquid and stabilization of mold | type operation | movement can be aimed at.

  It is preferable that the knockout pin driving means has a conveying means for gripping the work in cooperation with an operation of completely protruding the work from the die, and then conveying the work.

  As a specific knockout pin driving means, a means in which a plurality of cylinders, each having a stroke size set in accordance with the amount of protrusion of the workpiece at a plurality of stages by the knockout pin, is combined in series and / or in parallel. Can be illustrated.

Furthermore, the hot forging method of the present invention that solves the above-mentioned problem is a hot forging comprising a punch, a die provided opposite to the punch, and a knockout pin that is combined with the die and movable in the axial direction. A hot forging method performed by an apparatus,
Placing the workpiece in the die;
Hot forging the workpiece with the die, the knockout pin and the punch;
A step of projecting the workpiece after hot forging into a plurality of stages by the knockout pin;
And a step of reducing the contact area by separating the knockout pin from the work for each of a plurality of stages of projecting the work .

  The hot forging device of the present invention will be described below based on a detailed embodiment.

The hot forging device of this embodiment is characterized by a knockout pin driving means for driving a knockout pin that projects a workpiece from the die. The knockout pin driving means drives the knockout pin so that the work is divided into a plurality of stages and protrudes from the die. Here, any number of knockout pins and knockout pin driving means may be used for one set of molds. Further, the knockout pins and the knockout pin driving means do not necessarily have to correspond one-to-one, and the number of each can be determined as necessary.
Further, the knockout pin driving means includes a mechanism that reduces the contact area by separating the knockout pin from the work for each of a plurality of stages of protruding the work.

First, project the workpiece with the knockout pin so that it does not fall out of the die. In this case, an appropriate value for the protrusion amount of the work is determined by the shape of the die and the work. Thereafter, by separating the knockout pin from the workpiece, the workpiece that is in close contact with the die by hot forging reduces the contact area between the die and the knockout pin by this protrusion, and the amount of heat transfer from the workpiece to the die can be reduced. The protrusion for reducing the contact area between the workpiece, the die and the knockout pin is preferably performed as soon as possible after the hot forging is completed. For example, the protrusion can be performed at a speed substantially synchronized with the moving speed of the punch.

  Thereafter, if necessary, the workpiece is completely ejected from the die. The timing for completely projecting the workpiece from the die is the timing at which the transfer means that transports the workpiece to the next process moves to the vicinity of the workpiece and grips the workpiece, or the mold is completely opened and does not interfere with the punch etc. The timing when the workpiece can be detached from the mold. In particular, it is preferable that the conveying means and the knockout pin driving means cooperate. Specifically, it is preferable to perform a gripping operation for transporting the workpiece in cooperation with an operation in which the workpiece is completely ejected by the knockout pin driving unit.

  The specific mechanism by which the knockout pin driving means drives the knockout pin is not particularly limited. For example, a linear movement mechanism such as a combination mechanism of a plurality of cylinders (hydraulic mechanisms), a cam mechanism, or a screw mechanism can be used. The combination mechanism of a plurality of cylinders can be realized by combining a plurality of cylinders having respective strokes corresponding to the protruding amounts for projecting the workpiece in a plurality of stages in series or in parallel. Here, in addition to a configuration in which the amount of movement of the knockout pin drive means itself is controlled to move the knockout pin in a plurality of stages, a form in which the knockout pin itself moves in a plurality of stages can be employed.

  The hot forging device of the present invention will be described below in detail based on examples. In the following description, the description is focused on the periphery of the knockout pin and the knockout pin driving means, which is a feature of the present invention, and other portions are omitted as appropriate.

(Constitution)
As shown in FIGS. 1 to 5, the hot forging device of the present embodiment includes a punch (not shown), a die 11, a knockout pin 12, and a knockout pin driving means 13 as main mechanisms. The die 11 has a space for inserting a tip of each punch and knockout pin 12 and defining a cavity in combination with the tip. That is, the cavity is defined by the combination of the punch, the die 11 and the knockout pin 12. The heated workpiece W is inserted into the cavity.

  The knockout pin 12 has a distal end portion inserted into the die 11 and a knockout pin main body having a uniform diameter, and a knockout pin main body formed at the end opposite to the distal end portion of the knockout pin main body. And a flange portion having a large diameter. The tip of the knockout pin 12 is combined with the die 11 and is movable in the axial direction.

  Knockout pin 12 is combined with a knockout pin return spring 122. The knockout pin return spring 122 is a spring having a smaller diameter than the flange portion of the knockout pin 12, and is disposed around the knockout pin main body. When the knockout pin 12 is combined with the die 11, the knockout pin return spring 122 is held between the flange portion of the knockout pin 12 and the die 11, and the knockout pin is knocked out in the direction opposite to the direction in which the knockout pin body is inserted into the die 11. The pin 12 is energized.

  Knockout pin 12 is housed in knockout pin holder 123. The knockout pin holder 123 is combined with the die 11 to limit the movement of the knockout pin 12 in the axial direction. Specifically, the knockout pin 12 is held so that the knockout pin 12 does not come off the die 11. The pressure applied from the punch directly acts on the surface where the knockout pin holder 123 restricts the movement of the knockout pin 12. The portion of the knockout pin holder 123 opposite to the portion in contact with the die 11 is fixed to the press bed 14 so as to withstand this pressure. The knockout pin holder 123 and the press bed 14 have an insertion hole through which the rod of the knockout pin driving means 13 that drives the knockout pin 12 is inserted.

  The knockout pin driving means 13 has a structure in which two types of cylinders 131 and 132 having different strokes are connected in series. The cylinder 131 close to the knockout pin 12 has a larger stroke than the cylinder 132.

  The barrel portions of the two cylinders 131 and 132 are integrated. The piston rod of the cylinder 132 can directly push the piston of the cylinder 131 from the cylinder bottom side, and the piston of the cylinder 131 can be moved even if only the cylinder 132 is operated. On the other hand, when only the cylinder 131 moves, the piston of the cylinder 131 can move freely regardless of the piston of the cylinder 132. Therefore, when the cylinder 132 is operated, the piston of the cylinder 131 is also moved by the stroke of the cylinder 132. When the cylinder 131 is operated, the piston of the cylinder 131 is operated for the stroke of the cylinder 131. The rod head of the cylinder 131 is inserted into the aforementioned insertion hole, and presses the knockout pin 12 from the flange portion side.

  The size of the stroke of the cylinder 132 is such a size that the workpiece W after hot forging is not protruded from the die 11. The stroke of the cylinder 131 is such a size that the work W after hot forging protrudes from the die 11. Therefore, when only the cylinder 132 is operated, the workpiece W moves to such an extent that it is not completely projected in the die 11. When the cylinder 131 is operated, the workpiece W is completely protruded from the die 11.

  Furthermore, this apparatus has conveying means 21 and 22 as shown in FIGS. The conveying means 21 and 22 are tip portions of a robot arm (not shown), and can grip and convey the workpiece W before and after hot forging by narrowing the distance between them. The conveying means 21 and 22 can move in an arbitrary space near the punch and the die 11.

(Function and effect)
Since it has the above configuration, the hot forging device of this embodiment exhibits the following effects.
(1) The work W is pressed by the punch in the cavity formed by the punch, the die 11 and the knockout pin 12 to complete forging (FIG. 1). The workpiece W before forging is heated to 1200 ° C.
(2) The punch 132 is moved and the cylinder 132 is operated. When the cylinder rod of the cylinder 131 is moved by the stroke of the cylinder 132, the rod head of the cylinder 131 presses the flange portion of the knockout pin 12 to move the knockout pin 12 by the stroke of the cylinder 132. . As the knockout pin 12 moves, the workpiece W also moves in the die 11 (FIG. 2). As a result, although the workpiece W does not fall out of the die 11, the contact area between the workpiece W and the die 11 is reduced, and the amount of heat transfer from the workpiece W to the die 11 is reduced. Therefore, prevention of thermal deterioration of the die 11 and temperature reduction of the workpiece W can be suppressed.
(3) Return the cylinders 131 and 132 to their original state. Then, the knockout pin 12 returns to the normal state in which the flange portion abuts against the knockout pin holder 123 by the knockout pin return spring 122 (FIG. 3). As a result, the contact area between the workpiece W and the knockout pin 12 is reduced, and the amount of heat transfer from the workpiece W to the knockout pin 12 is reduced, thereby preventing thermal degradation of the knockout pin 12 and lowering the temperature of the workpiece W. Can be suppressed.
(4) After the punch moves and the mold opening is completed, the cylinder 131 is operated when the conveying means 21 and 22 approach the vicinity of the opening of the die 11. The rod head of the cylinder 131 presses the flange portion of the knockout pin 12 to move the knockout pin 12 by the stroke of the cylinder 131. As the knockout pin 12 moves, the workpiece W is also dropped from the die 11 and moved to the transport means 21 and 22 (FIG. 4). The conveying means 21 and 22 hold the workpiece W that has moved in cooperation with the operation of the cylinder 131.
(5) Thereafter, the cylinder 131 is returned to the original state. Then, the knockout pin 12 returns to the normal state in which the flange portion abuts against the knockout pin holder 123 by the knockout pin return spring 122 (FIG. 5). As a result, the contact area between the workpiece W and the knockout pin 12 is reduced, and the amount of heat transfer from the workpiece W to the knockout pin 12 is reduced, thereby preventing thermal degradation of the knockout pin 12 and lowering the temperature of the workpiece W. Can be suppressed.
(6) The workpiece W is conveyed to the next step. Subsequently, a new work W is conveyed and a new process is repeated from the process (1).
(7) As described above, after the work W is hot forged, the life of the die can be improved by protruding the workpiece W to the extent that it does not fall out completely from the die 11.
[Modification]
Instead of the combination of two cylinders as the knockout pin driving means 13 in the above-described embodiment, the following configuration can be adopted. As shown in FIG. 6, one cylinder 31 can be substituted. The cylinder 31 can be stopped in the middle of the stroke, and two or more strokes can be realized. As shown in FIG. 7, a cam mechanism 32 can be employed as the knockout pin driving means 13. Further, as shown in FIG. 8, a screw mechanism 332 can be employed instead of the knockout pin driving means 13. By rotating the rod by decelerating the rotation of the motor 331 with the gear 333, the screw mechanism acts and the rod can move in the axial direction. In addition, an appropriate actuator capable of changing the stroke can be employed.

It is the schematic shown about the mode of operation of the hot forging device of an example. It is the schematic shown about the mode of operation of the hot forging device of an example. It is the schematic shown about the mode of operation of the hot forging device of an example. It is the schematic shown about the mode of operation of the hot forging device of an example. It is the schematic shown about the mode of operation of the hot forging device of an example. It is the schematic shown about the hot forging apparatus of the modification. It is the schematic shown about the hot forging apparatus of the modification. It is the schematic shown about the hot forging apparatus of the modification. It is the schematic shown about the hot forging apparatus of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Die 12 ... Knockout pin 122 ... Knockout pin return spring 123 ... Knockout pin holder 13 ... Knockout pin drive means 131, 132 ... Cylinder 14 ... Press bed 21, 22 ... Conveyance means 31 ... Cylinder 32 ... Cam mechanism 331 ... Motor 332 ... Screw mechanism 333 ... Gear

Claims (5)

A punch, a die provided opposite to the punch, a knockout pin combined with the die and movable in an axial direction, and a workpiece after hot forging with the punch, the die and the knockout pin. A hot forging device having a knockout pin drive means for moving the knockout pin in a direction protruding from a die,
The knockout pin driving means includes a mechanism for projecting the workpiece after hot forging in a plurality of stages and a mechanism for reducing the contact area by separating the knockout pin from the workpiece for each of a plurality of stages of projecting the workpiece. A hot forging device comprising:   2. The hot forging device according to claim 1, further comprising a conveying unit that grips the workpiece and then conveys the workpiece in cooperation with an operation in which the knockout pin driving unit completely projects the workpiece from the die.   2. The knockout pin driving means is a means in which a plurality of cylinders, each having a stroke size set in accordance with the amount of protrusion of the workpiece at a plurality of stages by the knockout pin, are combined in series and / or in parallel. Or the hot forging apparatus of 2 or 2. A hot forging method performed by a hot forging apparatus having a punch, a die provided opposite to the punch, and a knockout pin that is combined with the die and movable in the axial direction,
Placing the workpiece in the die;
Hot forging the workpiece with the die, the knockout pin and the punch;
A step of projecting the workpiece after hot forging into a plurality of stages by the knockout pin;
And a step of reducing the contact area by separating the knock-out pin from the work for each of a plurality of stages of projecting the work .   5. The hot forging method according to claim 4, further comprising a step of gripping the workpiece and then transporting the workpiece in cooperation with an operation in which the knockout pin completely projects the workpiece from the die.

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