JP5847212B2 - Hot press machine - Google Patents

Description

The present invention relates to a pressing device and a hot pressing method for forming a bent portion in a peripheral edge portion of a steel plate.

    In parts for vehicles, both safety and economy are achieved by using a member having a thin thickness and high strength. For this purpose, a so-called hot press is known in which a steel plate heated to a high temperature is cooled by a low-temperature press die and quenched. In this method, the steel sheet is heated to the austenitizing temperature or higher, and rapidly cooled at the same time as forming with a press machine to perform quenching.

  A certain type of vehicle component has a bent portion (stepped portion) having an L-shaped cross section at the periphery of the steel plate. When such a bent portion is formed by hot pressing, a lower mold having a step for forming the bent portion on the side surface, a pad portion disposed adjacent to the lower die in the horizontal direction, and a direction perpendicular to the pad portion. A press device provided with an upper die arranged to face each other is used.

  In this pressing apparatus, when the upper die is moved downward, the steel plate as the material to be pressed is sandwiched between the upper die and the pad portion, and the step of forming the bent portion of the lower die is utilized to make the steel plate A bent portion is formed at the peripheral edge.

JP 2011-152547 A

However, when the upper mold moves down and the steel sheet is drawn into the step of the lower mold, wrinkles (wrinkles) occur at the peripheral edge of the steel sheet, and when the wrinkles become large, the wrinkled steel sheets partially overlap. Such a problem may occur. The wrinkles can be finally crushed by press working, but there is a problem that the strength of the portion is lowered.
According to the inventor's study, as shown in FIG. 6, when the step 101 of the bent portion of the steel plate 100 is large and the peripheral portion of the steel plate 100 is curved, wrinkles 103 are generated in the curved portion 102, It is known that the overlap of the steel plates 100 becomes remarkable, and such a problem can occur even in the cold press, but it also occurs remarkably in the hot press in which the steel plate 100 is pressed while being heated and softened. .

In view of the above problems, the hot press apparatus of the present invention is supported by a lower mold having a step for forming a bent portion on a side surface and supported by a spring so as to be vertically movable, and is disposed adjacent to the lower mold in the horizontal direction. A pad portion formed thereon, an upper die disposed to face the pad portion in a vertical direction, and the upper die is moved downward to sandwich the steel plate between the upper die and the pad portion. When the bent portion is formed in the peripheral portion of the steel plate, it moves down with the upper mold and restricts the movement of the peripheral portion of the steel plate protruding in the horizontal direction from the lower mold, thereby A restricting portion that suppresses the formation of wrinkles, and the restricting portion is disposed in a horizontal direction away from the lower mold so as not to contact the lower mold when the restricting portion moves down, In addition, the restricting portion is in front of the upper mold so as to come into contact with the steel plate. Wherein the lower end surface of the restricting portion is higher in the vertical direction from the lower end surface of the upper mold.

According to the present invention, when the bent portion is formed in the peripheral portion of the steel plate by press working, the generation of wrinkles in the peripheral portion can be suppressed, and the strength of the pressed part can be increased.
In particular, the effect is great when the step of the bent portion of the steel plate is large and the peripheral edge of the steel plate is curved. The present invention can also be applied to a cold press, but the effect is great when applied to a hot press.

It is sectional drawing of the press apparatus in embodiment of this invention. It is sectional drawing of the press apparatus in embodiment of this invention. It is sectional drawing of the press apparatus in embodiment of this invention. It is sectional drawing of the press apparatus in embodiment of this invention. It is a partial top view of the press apparatus in embodiment of this invention. It is a perspective view of the pressed steel plate.

Embodiments of the present invention will be described with reference to the drawings. FIG. 5 is a partial plan view of the press device 10, and FIGS. 1 to 4 are cross-sectional views taken along the line XX of FIG. 5 .

  As shown in the figure, the lower mold 1 is fixed on a base 2 and has a step 3 for forming a bent portion on a side surface. The pad portion 4 is disposed adjacent to the step 3 side of the lower mold 1 in the horizontal direction. The pad portion 4 is supported by a spring 5 (for example, a gas spring) disposed on the base 2 so as to be movable up and down.

  The upper mold 6 is disposed to face the pad portion 4 in the vertical direction. The restricting portion 7 is disposed adjacent to the upper mold 6. The upper die 6 and the restricting portion 7 are driven up and down by a driving device (not shown) in order to press the steel plate 100 that is a pressed material. The upper mold 6 and the restricting portion 7 may be integrally formed as an upper mold.

  In this case, when the upper mold 6 moves downward and the steel plate 100 is sandwiched between the upper mold 6 and the pad portion 4 and the bent portion is formed on the peripheral edge of the steel plate 100, By controlling the movement of the peripheral portion of the steel plate 100 that moves down together with the die 6 and protrudes from the lower die 1 in the horizontal direction, the formation of wrinkles at the peripheral portion of the steel plate 100 is suppressed. In particular, as shown in FIG. 6, the effect is great when the step 101 of the bent portion of the steel plate 100 is as large as 120 mm to 150 mm and the peripheral portion of the steel plate 100 is curved.

  Hereinafter, the hot press method by the press apparatus 10 is demonstrated.

  First, it heats more than the austenitizing temperature with the steel plate 100 heating furnace. Next, as shown in FIG. 1, the heated steel plate 100 is transported from the heating furnace in a state where the upper die 6 and the regulating portion 7 are moved up to the top dead center, and the lower die 1 and the pad portion 4. Place on top. In this case, the steel plate 100 straddles the step 3 of the lower mold 1 from above the pad portion 4 and protrudes from the upper end of the lower mold 1 in the horizontal direction.

Next, as shown in FIG. 2, the upper die 6 and the restricting portion 7 are moved downward. In the state of FIG. 2, the steel plate 100 is sandwiched between the upper die 6 and the pad portion 4 , and the lower end surface of the upper die 6 is in contact with the upper surface of the steel plate 100 placed on the pad portion 4. The lower end surface of the restricting portion 7 is preferably not in contact with the upper surface of the steel plate 100 yet.

  That is, in the state of FIG. 1, the vertical height of the lower end surface of the upper mold 6 from the upper surface of the steel plate 100 is h1, and the vertical height of the lower end surface of the restricting portion 6 from the upper surface of the steel plate 100 is h2 is larger than h1. (H2> h1) In the state of FIG. 2, the height in the vertical direction from the upper surface of the steel plate 100 to the lower end surface of the restricting portion 6 is h = h2-h1.

And as shown in FIG. 3, the upper metal mold | die 6 and the control part 7 are moved further down. Then, the upper mold 6 pushes down the pad portion 4 on which the steel plate 100 is placed against the repulsive force of the spring 5. The steel plate 100 is held by the pressing force of the upper mold 6 and the repulsive force of the spring 5. As a result, the steel plate 100 is drawn into the step 3 of the lower mold 1 while sliding on the upper surface of the lower mold 1 to form a bent portion, and the steel plate 100 is quenched.

  During the formation of the bent portion, the restricting portion 7 comes into contact with the upper surface of the steel plate 100 and restricts the movement of the peripheral portion of the steel plate 100, thereby suppressing the formation of wrinkles at the peripheral portion of the steel plate 100 and the overlapping of the steel plates 100. Yes. If the restricting portion 7 is not provided, the peripheral edge of the steel plate 100 is lifted, so that wrinkles of the peripheral edge of the steel plate 100 are generated.

In this case, by delaying the contact of the restricting portion 7 with the steel plate 100, the peripheral portion of the steel plate 100 is locally quenched, thereby preventing the steel plate 100 from cracking due to the stress caused by the drawing of the steel plate 100. .

Next, as shown in FIG. 4, the upper mold 6 and the restricting portion 7 are further moved downward. Then, the steel plate 100 is drawn deeper into the step 3 of the lower mold 1 and the bent portion becomes larger, and the restricting portion 7 pushes down the edge of the peripheral edge of the steel plate 100. In this case, in order to allow the restricting part 7 to escape downward without coming into contact with the lower mold 1, the restricting part 7 is arranged to be separated from the lower mold 1 in the horizontal direction. The horizontal distance d between the restricting portion 7 and the lower mold 1 is preferably larger than the thickness t of the steel plate 100 (d> t).

  The press device 10 of the present embodiment is highly effective when applied to a hot press that tends to form wrinkles, but can also be applied to a cold press that does not heat the steel plate 100.

DESCRIPTION OF SYMBOLS 1 Lower die 2 Base 3 Level | step difference 4 Pad part 5 Spring 6 Upper die 7 Control part 10 Press apparatus 100 Steel plate

Claims (2)

A lower mold having a step for forming a bent portion on a side surface;
A pad portion that is supported by a spring so as to be movable up and down, and is disposed adjacent to the lower mold in the horizontal direction;
An upper mold disposed perpendicularly to the pad portion;
When the upper mold is moved downward and the steel plate is sandwiched between the upper mold and the pad portion to form a bent portion at the peripheral edge of the steel plate, the upper mold is moved downward together with the lower mold. A regulation part that suppresses the formation of wrinkles in the peripheral part of the steel sheet by regulating the movement of the peripheral part of the steel sheet protruding in the horizontal direction from the mold , and
The restricting portion is configured to prevent the lower mold from coming into contact with the lower mold when the restricting portion moves down.
The lower end surface of the restricting portion is arranged in a vertical direction with respect to the lower end surface of the upper mold so that the lower end surface of the restricting portion contacts the steel plate with a delay from the upper die. A hot press machine characterized by being raised . Horizontal distance of the lower tool and the regulating portion, the hot pressing apparatus according to claim 1, wherein the greater than the thickness of the steel sheet.

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