HOT PRESSING APPARATUS AND METHOD FOR MANUFACTURING A HOT PRESSING PRODUCT.

Abstract

A hot pressing apparatus includes a first die part 2 and a second die part 3, and a control unit 9. At least one of the first and second die parts 2 and 3 includes a recess 3a in the surface facing the other die part in the pressing direction. A movable die part 4 is provided in the recess 3a. The control unit 9 controls the movable die part 4 such that the clamping period at bottom dead center, during which the first and second die parts 2 and 3 are at bottom dead center, includes a butt contact period during which the movable die part 4 makes butt contact with the sheet metal B and a non-contact period during which the movable die part does not make contact with the sheet metal B.

Claims

1. A hot pressing apparatus comprising: a first die part; a second die part capable of moving relative to the first die part in a pressing direction; and a control unit adapted to control the relative movement of the first die part and the second die part, wherein at least one of the first die part and the second die part includes a recess in a surface facing the other die part in the pressing direction, a movable die part is provided in the recess, the movable die part being movable in a direction that crosses the surface facing the other part,and the control unit controls a position of the moving die part such that a heated, press-formed sheet metal is held between the first die part and the second die part, and a clamping period at bottom dead center during which the first die part and the second die part are at bottom dead center includes a butt contact period during which the moving die part is in a butt contact position where the moving die part makes butt contact with the sheet metal and a non-contact period during which the moving die part is in a retracted position where it does not make contact with the sheet metal.

2. The hot pressing apparatus according to claim 1, wherein the control unit causes the moving die part to make butt contact with the sheet metal at an early stage of the clamping period at the bottom dead center and then causes the moving die part to separate from the sheet metal at a late stage of the clamping period at the bottom dead center.

3. The hot pressing apparatus according to claim 1, wherein the control unit causes the moving die part to separate from the sheet metal at an early stage of the clamping period at the bottom dead center and then causes the moving die part to make butt contact with the sheet metal at a late stage of the clamping period at the bottom dead center.

4. The hot pressing apparatus according to any one of claims 1 to 3, wherein the recess includes a first recess provided in the first die part and a second recess provided in the second die part and is positioned to face the first recess, and the movable die part is located in at least one of the first and second recesses.

5. The hot pressing apparatus according to claim 4, wherein the movable die portion is provided in each of the first and second recesses. CPC7 ίη / 77Ω7 / B / YILI 6. The hot pressing apparatus according to any one of claims 1 to 3, wherein a surface of the movable die portion that will be in contact with the sheet metal when the movable die portion makes butt contact with the sheet metal while the die portions are at bottom dead center is positioned to be flush with a die surface to be in contact with the sheet metal surrounding the recess provided with the movable die portion.

7. The hot pressing apparatus according to any one of claims 1 to 3, wherein an upper surface of the movable die portion includes a protrusion adapted to make butt contact with the sheet metal and a recess adapted to make butt contact with the sheet metal when the movable die portion makes butt contact with the sheet metal while the die portions are at bottom dead center.

8. The hot pressing apparatus according to any one of claims 1 to 3, wherein an upper surface of a movable die part in one of the first die parts and the second die part includes a recess or a recessed or protruding protrusion in the pressing direction; a surface of the other die part or movable die part facing the movable die part in the pressing direction has a shape corresponding to the recess or protrusion on the upper surface of the movable die part; and, when the movable die part makes butt contact with the sheet metal while the die parts are at bottom dead center, the surface of the other die part or movable die part makes butt contact with the sheet metal facing the movable die part.

9. The hot pressing apparatus according to any one of claims 1 to 3, wherein the control unit adjusts a distance between the sheet metal and the movable die part which is found when the movable die part is in the retracted position.

10. A method for manufacturing a hot-pressed product, comprising: placing a heated metal sheet between a first die part and a second die part; forming the metal sheet by pressing it by bringing the first die part and the second die part together in a pressing direction; holding the metal sheet while the first die part and the second die part are at bottom dead center;and moving, towards the sheet metal, a movable die portion provided in a recess in at least one of the first die portion and the second die portion during a holding period at bottom dead center during which the sheet metal is held at bottom dead center, wherein the holding period at bottom dead center includes a butt contact period during which the movable die portion is in a butt contact position where the movable die portion makes butt contact with the sheet metal and a non-contact period during which the movable die portion is in a retracted position where it does not make contact with the sheet metal.

11. The method for manufacturing a hot-pressed product according to claim 10, wherein the moving die portion makes butt contact with the sheet metal at an early stage of the clamping period at the bottom dead center and then the moving die portion separates from the sheet metal at a late stage of the clamping period at the bottom dead center.

12. The method for manufacturing a hot-pressed product according to claim 10, wherein the movable die portion separates from the sheet metal at an early stage of the clamping period at the bottom dead center and then the movable die portion makes butt contact with the sheet metal at a late stage of the clamping period at the bottom dead center.

13. The method for manufacturing a hot-pressed product according to any one of claims 10 to 12, wherein a surface of the movable die portion that will be in contact with the sheet metal when the movable die portion makes butt contact with the sheet metal while the die portions are at bottom dead center is positioned to be flush with a die surface that will be in contact with the sheet metal surrounding the recess provided with the movable die portion.

14. The method for manufacturing a hot-pressed product according to any one of claims 10 to 12, wherein an upper surface of the movable die portion includes a protrusion adapted to make butt contact with the sheet metal and a recess adapted to not make contact with the sheet metal when the movable die portion makes butt contact with the sheet metal while the die portions are at bottom dead center.

15. The method for manufacturing a hot-pressed product according to any one of claims 10 to 12, wherein an upper surface of a movable die part in one of the first die parts and the second die part includes a recess or protrusion in the pressing direction; a surface of the other die part or movable die part facing the movable die part in the pressing direction has a shape corresponding to the recess or protrusion on the upper surface of the movable die part; and, when the movable die part makes butt contact with the sheet metal while the die parts are at bottom dead center, the surface of the other die part or movable die part facing the movable die part makes butt contact with the sheet metal.

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