JP4856919B2 - Hemming mold - Google Patents

Description

  The present invention relates to a hemming die for performing a hemming process, and more particularly to an improvement of a die and a punch that perform acute angle bending of a workpiece.

  As shown in FIG. 2, the hemming mold includes a die base 3 supported by a mold support base 1, and a movable die 5 is provided on the die base 3 so as to be movable up and down. The movable die 5 is always urged upward by an urging means such as a coil spring, and the upper surface of the movable die 5 has an acute angle for bending the plate-like workpiece W at an acute angle. A V-shaped groove 7 is formed. And in order to crush the part bent by the acute angle of the workpiece | work W, the lower surface 9 of the said movable die 5 and the plane 11 of the die base 3 are provided facing up and down.

  In the above configuration, after the plate-like workpiece W is placed on the movable die 5, when the workpiece W is pressed by the tip of the punch 13, the movable die 5 is lowered against the biasing means, After the lower surface 9 and the flat surface 11 come into contact with each other, the workpiece W is pressed against the V-groove 7, and the workpiece W is bent at an acute angle.

  Thereafter, the workpiece W is removed, and a portion (folded portion) bent at an acute angle of the workpiece W is disposed between the flat surface 11 of the die base 3 and the lower surface 9 of the movable die 5. Then, the punch 13 is engaged with the V groove 7 of the movable die 5 and the movable die 5 is pressed downward, whereby the folded portion of the workpiece W is crushed, that is, hemmed. (Patent Document 1).

As understood from the above description, in the hemming mold, the punch 13 may be directly engaged with the V groove 7 of the movable die 5 to press the movable die 5 strongly.
JP-A-6-87028

  By the way, at the bottom of the V-groove 7 in the movable die 5 in the hemming mold, when finishing such as grinding of the inclined surface 15 in the V-groove 7, interference with a processing tool (for example, a grinding wheel) is avoided. For this purpose, a small relief groove 17 is formed. As described above, when the movable die 5 is pressurized by engaging the V groove 7 of the movable die 5 and the punch 13, the inclined surface of the V groove 7 and the punch 13 are obtained so that a large pressing force can be obtained. The inclined surface 13F is formed so as to be in surface contact in advance.

  Therefore, in the conventional configuration, when the punch 13 and the V groove 7 of the movable die 5 are engaged and pressurized, a wedge phenomenon occurs between the V groove 7 of the movable die 5 and the punch 13 due to the wedge effect. Sometimes. Therefore, a hemming mold that does not cause such a biting phenomenon is desired.

The present invention has been made in view of the conventional problems as described above, and is provided with a movable die on a die base so as to be movable up and down, and a punch that can be engaged and disengaged in an acute-angled V groove formed on the upper surface of the movable die. A hemming mold that may cause a biting phenomenon when the punch is engaged with the V groove and pressurized, and the inclination angle of the V groove is equal to the inclination angle of the front end side of the punch. Yes formed, when engaged with the punch to the V groove, I configuration der the tip of the punch comes into contact with the bottom of the relief groove formed in the bottom of the V groove, the bottom of the V groove It is formed in a concave curved surface, and has a minute gap between the inclined surface of the V groove and the inclined surface of the punch when the tip of the punch comes into contact with the bottom of the V groove. Is.

In the hemming mold, the tip of the punch is formed in an arc-shaped convex curved surface having a radius smaller than the radius of the concave curved surface at the bottom of the escape groove.

Further, in the hemming die, when the tip of the punch is elastically deformed by applying a pressure to the punch, the inclined surface of the punch is in contact with the inclined surface of the V groove. It is a feature.

  According to the present invention, since the tip end portion of the punch is in contact with the bottom portion of the relief groove formed at the bottom portion of the V groove in the movable die, the biting phenomenon between the V groove 7 and the punch can be avoided. It can be done.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Since the overall configuration of the hemming mold is the same as the conventional configuration, the same reference numerals are given to the components having the same functions. The explanations made are omitted.

  Referring to FIG. 1, a relief groove 17 is formed at the bottom of the V groove 7 of the movable die 5 in the hemming die according to the embodiment of the present invention, and the bottom 19 of the relief groove 17 has an arcuate concave shape. It is formed on a curved surface. The inclined surface 13F of the punch 13 that can be engaged with the V groove 7 is formed in parallel with the inclined surface 15 of the V groove 7. That is, the inclination angle of the V groove 7 and the inclination angle of the tip end side of the punch 13 are formed to be equal.

  The tip 13E of the punch 13 is formed in an arc-shaped convex curved surface having a small radius smaller than the radius of the bottom 19 of the escape groove 17. When the punch 13 is engaged with the V-groove 7, the tip 13 E of the punch 13 is in contact with the bottom 19 of the escape groove 17 in the V-groove 7, and the tip 13 E is in contact with the bottom 19. In a contacted state (a state in which no pressure is applied to the punch 13), a minute gap C of, for example, about 0.01 mm is provided between the inclined surface 15 of the V groove 7 and the inclined surface 13F of the punch 13. is there. The minute gap C is a gap that allows the inclined surface 13F of the punch 13 to contact the inclined surface 15 of the V groove 7 when a pressure is applied to the punch 13 and the tip portion 13E of the punch 13 is elastically deformed. is there.

  In the configuration as described above, as described above, after positioning the bent portion of the workpiece W on the flat surface 11 of the hemming die, when the punch 13 is engaged with the V groove 7 of the movable die 5, the tip of the punch 13 is engaged. The portion 13E contacts the bottom portion 19 of the escape groove 17 in the V groove 7. Thereafter, pressure is applied to the punch 13 to lower the movable die 5, and the folded portion of the workpiece W is crushed between the lower surface 9 of the movable die 5 and the flat surface 11, thereby causing hemming. Processing is performed.

  When hemming is performed as described above, the tip end portion 13E of the punch 13 is elastically deformed, and the inclined surface 13F of the punch 13 is brought into contact and contact with the inclined surface 15 of the V groove 7, so that a large pressure is applied to the punch 13. And the bent portion of the workpiece W can be pressurized by the lower surface 9 of the movable die 5.

  When the application of a large pressure to the punch 13 is released after the hemming process as described above is performed, the elastically deformed tip portion 13E of the punch 13 is restored to the original state. 7 is released from the close contact state between the inclined surface 15 and the inclined surface 13F of the punch 13. Therefore, no biting phenomenon occurs between the V groove 7 and the punch 13.

  Further, according to the above configuration, since the bottom portion 19 of the escape groove 17 in the V-groove 7 is formed in an arc-shaped concave curved surface, stress concentration can be avoided and the life of the movable die 5 can be improved. is there.

It is explanatory drawing which shows the structure of the principal part of the hemming metal mold | die which concerns on embodiment of this invention. It is explanatory drawing which shows the structure of a general hemming metal mold | die.

Explanation of symbols

3 Die base 5 Movable die 7 V groove 9 Lower surface 11 Plane 13 Punch 13E Tip 13F Inclined surface 15 Inclined surface 17 Escape groove 19 Bottom

Claims (3)

When a movable die is provided on the die base so as to be movable up and down, and a punch that can be engaged and disengaged is formed in an acute-angled V groove formed on the upper surface of the movable die. A hemming mold that may cause a biting phenomenon , wherein the inclination angle of the V groove and the inclination angle of the tip end side of the punch are equal, and when the punch is engaged with the V groove, What configuration der the tip of the punch comes into contact with the bottom of the relief groove formed in the bottom of the V groove, the bottom of the V groove Yes formed on the concave surface, the tip of the punch to the bottom of the V groove A hemming die having a minute gap between the inclined surface of the V-groove and the inclined surface of the punch when the parts are brought into contact with each other. 2. The hemming die according to claim 1, wherein a tip end portion of the punch is formed as an arc-shaped convex curved surface having a radius smaller than a radius of a concave curved surface at a bottom portion of the escape groove. Type. 3. The hemming die according to claim 1, wherein when the tip of the punch is elastically deformed by applying a pressure to the punch, the inclined surface of the punch comes into contact with the inclined surface of the V groove. A hemming mold characterized by having a configuration.

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