Device for judging collision of a die cushion mechanism and system for judging collision

• US 20070012083A1
• Filed: 06/30/2006
• Published: 01/18/2007
• Est. Priority Date: 07/04/2005
• Status: Abandoned Application

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Okita, Tadashi, Iwashita, Yasusuke, Kawamura, Hiroyuki, Ikai, Satoshi
• Application Number:
  US11/477,804
• Publication Number:
  US 20070012083A1
• Time in Patent Office: Days
• US Class Current: 72/350
• CPC Class Codes: B21D 24/10 Devices controlling or operating blank holders independently, or in conjunction with dies
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 2219/37411 Measure contact from force and velocity detection
• CPC Class Codes: G05B 2219/37622 Detect collision, blocking, stall by change, lag in position
• CPC Class Codes: G05B 2219/37624 Detect collision, blocking by measuring change of velocity or torque
• CPC Class Codes: G05B 2219/42123 Position loop then force, current loop
• CPC Class Codes: G05B 2219/45131 Turret punch press

Abstract

A device (110) for judging the collision of a slide (24) with a die cushion in a die cushion mechanism (20) which produces a force against the slide in a press machine using a servo motor (18) as a drive source, comprising force detection means (21) for detecting a force produced between the die cushion and the slide; and comparator means (95) for comparing a force detection value (Fd) detected by the force detection means with a predetermined threshold value (L1); wherein, when the force detection value becomes greater than the threshold value, it is so judged that the slide has come into collision with the die cushion. Thus, the collision is judged within a short period of time and reliably. The collision may be judged by comparing differentiated values (Fd′, Fd″) of the force detection value, slide position detection value (Y1d) or slide position instruction value (Y1c) or other related threshold values. There can be further used a system for judging a collision which executes a plurality of methods for judging the collision.

Claims

1. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

force detection means for detecting a force produced between said die cushion and said slide; and

comparator means for comparing a force detection value detected by said force detection means with a predetermined threshold value;

wherein, when said force detection value becomes greater than said threshold value, it is so judged that said slide has come into collision with said die cushion.

2. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

force detection means for detecting a force produced between said die cushion and said slide; and

comparator means for comparing a force detection value detected by said force detection means with a force detection value before the operation detected by said force detection means before the operation of said die cushion;

wherein, when said force detection value becomes greater than said force detection value of before the operation, it is so judged that said slide has come into collision with said die cushion.

3. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

force detection means for detecting a force produced between said die cushion and said slide; and

comparator means for comparing a first-order differentiated value or a second order differentiated value of the force detection value detected by said force detection means with a predetermined threshold value;

wherein, when said first-order differentiated value or said second order differentiated value becomes greater than said threshold value, it is so judged that said slide has come into collision with said die cushion.

4. (canceled)

5. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

force instruction means for instructing a force to be produced between said die cushion and said slide;

force detection means for detecting a force produced between said die cushion and said slide; and

comparator means for comparing a force detection value detected by said force detection means with a force instruction value instructed by said force instruction means;

wherein, when said force detection value becomes greater than said force instruction value, it is so judged that said slide has come into collision with said die cushion.

6. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

speed detection means for detecting a speed of said die cushion; and

comparator means for comparing a speed detection value detected by said speed detection means with a predetermined threshold value;

wherein, when said speed detection value becomes greater than said threshold value, it is so judged that said slide has come into collision with said die cushion.

7. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

speed detection means for detecting a speed of said die cushion; and

comparator means for comparing a first-order differentiated value of the speed detection value detected by said speed detection means with a predetermined threshold value;

wherein, when said first-order differentiated value becomes greater than said threshold value, it is so judged that said slide has come into collision with said die cushion.

8. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

acceleration detection means for detecting an acceleration of said die cushion; and

comparator means for comparing an acceleration detection value detected by said acceleration detection means with a predetermined threshold value;

wherein, when said acceleration detection value becomes greater than said threshold value, it is so judged that said slide has come into collision with said die cushion.

9. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

slide position detection means for detecting a position of said slide; and

comparator means for comparing a slide position detection value detected by said slide position detection means with a predetermined threshold value;

wherein, when said slide position detection value becomes smaller than said threshold value, it is so judged that said slide has come into collision with said die cushion.

10. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

slide position instruction means for instructing a position of said slide; and

comparator means for comparing a slide position instruction value instructed by said slide position instruction means with a predetermined threshold value;

wherein, when said slide position instruction value becomes smaller than said threshold value, it is so judged that said slide has come into collision with said die cushion.

11. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

distance detection means for detecting a distance between said die cushion and said slide; and

comparator means for comparing a distance detected by said distance detection means with a predetermined threshold value;

wherein, when said distance becomes smaller than said threshold value, it is so judged that said slide has come into collision with said die cushion.

12. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

slide position detection means for detecting a position of said slide;

die cushion position detection means for detecting a position of said die cushion; and

comparator means for comparing a slide position detection value detected by said slide position detection means with a die cushion position detection value detected by said die cushion position detection means;

wherein, when said slide position detection value becomes smaller than or equal to said die cushion position detection value, it is so judged that said slide has come into collision with said die cushion.

13. (canceled)

14. A device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source, comprising:

slide position instruction means for instructing a position of said slide;

die cushion position instruction means for instructing a position of said die cushion; and

comparator means for comparing a slide position instruction value instructed by said slide position instruction means with a die cushion position instruction value instructed by said die cushion position instruction means;

wherein, when said slide position instruction value becomes smaller than or equal to said die cushion position instruction value, it is so judged that said slide has come into collision with said die cushion.

15. (canceled)

16. A system for judging the collision, comprising:

a first device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source; and

a second device for judging the collision of the slide with the die cushion in the die cushion mechanism which produces a force against the slide in the press machine using the servo motor;

wherein, when the first device for judging the collision and the second device for judging the collision have rendered the judgment of collision, it is so judged that said slide has come into collision with said die cushion.

17. A system for judging the collision, comprising:

a first device for judging the collision of a slide with a die cushion in a die cushion mechanism which produces a force against the slide in a press machine using a servo motor as a drive source;

a second device for judging the collision of the slide with the die cushion in the die cushion mechanism which produces a force against the slide in the press machine using the servo motor; and

switching means for changing a position control unit that controls said slide depending upon a position of said slide over to a force control unit that controls said slide depending upon a force acting on said slide;

wherein, when said second device for judging the collision is not rendering the judgment of collision after said switching means has changed said position control unit over to said force control unit as a result of the judgment of collision rendered by said first device for judging the collision, it is so judged that said slide has not collided with said die cushion, and said switching means changes said force control unit over to said position control unit.