JP2010172908A - Nut detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nut detection apparatus with which proper installation of a nut and presence/absence of a nut can be surely determined and with which positioning of a workpiece can be performed. <P>SOLUTION: The nut detection apparatus 30 includes: a pin 34 that is inserted into a through-hole c of a workpiece W and used for positioning the workpiece W; a continuity hole 56 drilled in the pin 34; and a wire 62 that is inserted into the continuity hole 56, with the tip end 64 made retractable in the side face of the pin 34. The wire 62 is provided with a magnet 74, a determining reed switch 78 for detecting the magnet 74, and a determination part 80 for determining proper installation of a nut 42 on the workpiece W as well as presence/absence of the nut 42. Then, when the tip end 64 of the wire 62 comes into contact with the inner periphery of the threaded hole 44 of the nut 42, with the determining reed switch 78 detects the stopped magnet 74, the determination part 80 determines it to be normal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nut detection device, and more particularly, to a nut detection device that is used, for example, in a component welding process and determines whether or not a nut is properly provided on a workpiece and whether or not a nut is present.

  For example, large sheet metal parts (workpieces) such as roofs, floors, and doors of passenger cars are set in a jig in a state of being combined with each other in an assembling process, and are joined by spot welding or the like. A plurality of nuts are fixed to each workpiece in advance by spot welding or the like, and are used for assembly of the workpieces by fastening with bolts or the like provided on other workpieces.

  By the way, in the process of welding the nut to the workpiece, the nut may not be attached to the workpiece due to an abnormality of the nut supply device etc. (nut missing of the nut), or the nut may be attached deviated from the position where the workpiece should be attached. (Position misalignment). Such shortage or misalignment of the nuts makes it impossible to assemble the workpieces thereafter, causing serious damage and loss in quality control. Therefore, various devices have been proposed as nut detection devices that detect such shortage of nuts and positional deviation (see Patent Document 1).

  For example, in the conventional nut detection device 10 shown in FIG. 5, a pin 16 having a diameter larger than that of the screw hole 14 of the nut 12 and tapered at the tip is vertically connected to the device main body 18 through the through hole 18a. It is provided so that reciprocation is possible. The pin 16 is biased upward by a spring 20, and when the pin 16 is inserted into the screw hole 14 of the nut 12, the tapered portion of the pin 16 comes into contact with the nut 12 and stops. . That is, when the nut 12 is properly provided on the workpiece 22, as shown in FIG. 5A, the pin 16 comes into contact with the nut 12 and stops at a predetermined position (normal stop position). At this normal stop position, the first contact 24 provided at the lower portion of the pin 16 contacts the second contact 26 provided in the apparatus main body 18 to send an electrical signal, whereby the nut 12 is normally provided. It is determined. On the other hand, when the nut 12 is missing, as shown in FIG. 5B, the pin 16 rises without coming into contact with the nut 12, and stops beyond the normal stop position. Then, the first contact 24 and the second contact 26 contact each other and then become non-contact, and an abnormality (shortage) of the nut 12 is determined.

Japanese Utility Model Publication No. 60-15480

  However, as described above, in the configuration in which the tapered portion of the pin 16 contacts the nut 12 and the pin 16 stops, it is necessary to insert the pin 16 accurately from the center of the screw hole 14 of the nut 12. That is, when the pin 16 is inserted from a position shifted from the center of the screw hole 14 to the one side (left side in FIG. 5), the pin 16 has a high tapered portion on one side as shown in FIG. It will contact the nut 12 in position. For this reason, the pin 16 stops before (below) the normal stop position, and the first contact 24 and the second contact 26 do not come into contact with each other. In this case, although the nut 12 is properly provided on the work 22, it may be determined that a missing item or a positional deviation of the nut 12 has occurred.

  In view of the above-described problems inherent in the nut detection device according to the prior art, the present invention has been proposed to suitably solve this problem, and accurately determines whether a nut is missing or misaligned. An object of the present invention is to provide a nut detection device that can perform the above-described operation.

In order to solve the above problems and achieve the intended purpose, the nut detection device according to the present invention is:
A nut detection device that determines whether or not a nut is properly provided at a position where a screw hole is aligned with the through-hole with respect to a workpiece in which the through-hole is formed;
A pin that is provided at the tip of the apparatus body, is inserted into and removed from the through hole of the workpiece, and positions the workpiece when inserted into the through hole;
A conduction hole drilled to penetrate from the device main body side of the pin to a side surface facing the outside of the workpiece in a state where the pin is inserted into the through hole;
A wire that is inserted into the conduction hole from the apparatus main body side and is reciprocally movable in the apparatus main body, and a tip portion of which can protrude and retract from a side surface of the pin;
A sensing object that reciprocates with the wire;
With the pin facing the screw hole of the nut properly provided on the workpiece, the wire is moved in the direction in which the tip protrudes from the side surface of the pin, and the tip contacts the inner surface of the screw hole. A detection body provided corresponding to a stop position of the detection body at the time, and capable of detecting the detection body;
It is provided with the determination part which determines whether the nut is appropriately provided in the workpiece | work based on the detection signal of the said detection body, and the presence or absence of a nut.
According to the first aspect of the present invention, the tip of the wire moving through the pin conduction hole is in contact with the nut, thereby determining whether or not the nut is normally provided and whether or not the nut is present. Therefore, erroneous determination does not occur even if the pin is inserted with a deviation from the center of the screw hole of the nut as in the prior art. Further, since it is not necessary to accurately insert the pin from the center of the screw hole, a device for highly controlling the insertion position of the pin is not required, and cost can be suppressed. Furthermore, the workpiece can be positioned by the pin when the pin is inserted into the through hole of the workpiece. That is, according to the nut detection device of the present invention, it is possible to position the workpiece while determining the shortage of nuts and the like. For example, the workpiece can be positioned and the workpieces can be welded together by this device.

  According to the nut detection device of the present invention, it is difficult to make a shortage of nuts or misjudgment of misalignment, and accurate determination is possible. Moreover, the workpiece can be positioned by the pins.

It is a longitudinal cross-sectional view which shows roughly the whole structure of the nut detection apparatus which concerns on an Example. It is explanatory drawing which shows a mode that the nut detection apparatus based on an Example operate | moves, Comprising: (a) shows the case where a magnet exists in a lower limit position, (b) is the inner peripheral surface of the screw hole of a nut. The state which contact | abutted is shown. It is explanatory drawing which shows the state which the nut was not provided in the workpiece | work but the front-end | tip part of the wire protruded from the pin. It is explanatory drawing which shows the state which the front-end | tip part of the wire protruded from the pin, when the nut has shifted and provided from the appropriate position of the workpiece | work. It is explanatory drawing which shows a mode that the conventional nut detection apparatus operate | moves, Comprising: (a) shows the case where the nut is provided in the workpiece | work appropriately, (b) shows the case where the nut is not provided in the workpiece | work. , (C) shows a case where a pin is inserted deviated from the center of the screw hole of the nut.

  Next, a nut detection device according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments. In the following description, “upper” and “lower” are designated when the nut detection device is viewed with reference to FIG.

  FIG. 1 is a longitudinal cross-sectional view illustrating the overall configuration of a nut detection device 30 according to the embodiment. The nut detection device 30 includes a device main body 32 configured in a cylindrical shape having a required length, a pin 34 provided at the upper end of the device main body 32, and a cylinder 36 provided at the lower end of the device main body 32. Inside the apparatus main body 32, a slide hole 38 is formed which is recessed upward by a predetermined length from the lower end surface of the apparatus main body 32. A through hole 32 a is formed from the upper end surface of the apparatus main body 32 to the upper portion of the slide hole 38. A connection recess 40 formed in a concave shape is provided on the upper portion of the apparatus main body 32, and the pin 34 is inserted into the connection recess 40.

  The pin 34 can be inserted into and removed from a through hole c provided in the work W so as to align with the screw hole 44 of the nut 42. The pin 34 includes a lower base portion 46, an insertion portion 48 protruding upward from the base portion 46, and a tapered portion 50 that gradually decreases in diameter upward. The base portion 46 is formed to have a diameter larger than the through hole c of the workpiece W, and a flange surface 52 capable of contacting the lower end surface of the workpiece W is formed on the upper surface thereof. Further, a connecting convex portion 54 protruding downward is formed on the lower surface of the base portion 46, and the pin 34 is attached to the device main body 32 by fitting the connecting convex portion 54 into the connecting concave portion 40 of the device main body 32. It comes to be installed. The insertion portion 48 of the pin 34 is set to have substantially the same diameter or slightly smaller diameter than the through hole c of the workpiece W and the screw hole 44 of the nut 42, and is inserted when the pin 34 is inserted into the screw hole 44 of the nut 42. The side surface of the portion 48 comes into contact with or slightly separated from the inner peripheral surface of the screw hole 44. Further, when the pin 34 is inserted into the through hole c of the work W, the insertion portion 48 of the pin 34 is fitted into the through hole c so that the work W can be positioned by the pin 34.

  The pin 34 includes a conduction hole 56 formed so as to penetrate from the apparatus main body 32 side to a side surface facing the outside of the workpiece W in a state where the pin 34 is inserted into the through hole c. That is, the conduction hole 56 is formed through the through-hole c when the insertion part 48 is inserted into the through-hole c of the workpiece W on the side surface of the insertion part 48 and the inlet 58 provided at the center of the lower surface of the connecting convex part 54. The outlet 60 provided in the part which comes out and faces the screw hole 44 of the nut 42 is communicated. Further, as shown in FIG. 1, the conduction hole 56 extends straight upward from the inlet 58 (in the insertion direction of the pin 34), and then laterally toward the side surface of the pin 34 (insertion of the pin 34). It is curved in the direction that intersects the direction. The inlet 58 is provided so as to align with the upper opening of the through hole 32a of the apparatus main body 32, and the conduction hole 56 and the through hole 32a communicate with each other when the pin 34 is attached to the apparatus main body 32. The

  In the slide hole 38 of the apparatus main body 32, a wire-like wire 62 is inserted into the conduction hole 56 from the apparatus main body 32 side so as to be reciprocally movable in the vertical direction. The wire 62 is made of a bendable metal wire or the like, and has a diameter that allows the through hole 56 and the through hole 32a to be inserted. And the said wire 62 is comprised so that the front-end | tip part 64 of the wire 62 can be projected and retracted from the side surface of the nut 42 through the said exit port 60 by moving up and down via the through-hole 32a and the conduction | electrical_connection hole 56. . That is, the distal end portion 64 of the wire 62 protrudes obliquely upward from the outlet / outlet 60 of the pin 34 when ascending (during forward movement) and is drawn into the conduction hole 56 when descending (returning). It has become. And when the front-end | tip part 64 of the wire 62 arrives at the said outlet 60, this front-end | tip part 64 can contact | abut to the internal peripheral surface of the screw hole 44 of the nut 42. FIG. The rear end portion of the wire 62 is connected to a piston member 66 disposed inside the cylinder 36 via a connecting portion 68, and the piston member 66 moves up and down to move the wire 62 back and forth. Is done.

  The piston member 66 is formed in a T shape from a rod portion 70 extending in the vertical direction and a plate portion 72 connected to the lower end of the rod portion 70, and air is introduced into the cylinder 36 by a drive source (not shown). By supplying and exhausting air, the piston member 66 is reciprocated up and down. The rod portion 70 has a vertical dimension larger than that of the cylinder 36, and the upper end side of the rod portion 70 faces the slide hole 38 through a hole portion 36 a provided in the upper portion of the cylinder 36. The connecting portion 68 for connecting the wire 62 is provided at the upper end of the rod portion 70 facing the slide hole 38. The plate portion 72 is formed to have a dimension that substantially matches the inner diameter of the cylinder 36 and is configured to slide on the inner peripheral surface of the cylinder 36. Here, the movement amount of the piston member 66 is from the lower limit position where the plate portion 72 is located on the bottom surface of the cylinder 36 to the upper limit position where the connecting portion 68 provided at the upper end of the rod portion 70 contacts the upper end of the slide hole 38. (See FIGS. 2 and 3). The piston member 66 is stopped when the distal end portion 64 of the wire 62 comes into contact with the inner peripheral surface of the screw hole 44 of the nut 42. That is, the air pressure by the drive source is set to a value that is larger than the load when the piston member 66 is raised and smaller than the rigidity of the wire 62. Therefore, after the wire 62 comes into contact with the nut 42, the piston member 66 stops without being raised.

  A magnet 74 as an object to be detected is annularly provided on the outer peripheral surface of the plate portion 72, and is configured to reciprocate up and down in the cylinder 36 together with the plate portion 72. Two reed switches 76 and 78 capable of detecting the magnet 74 are provided on the outer peripheral surface of the cylinder 36 so as to be separated from each other in the vertical direction. A reed switch provided on the lower side (hereinafter referred to as a start point reed switch 76) is provided corresponding to the position of the plate portion 72 (magnet 74) when the piston member 66 is at the lower limit position. When 76 detects the magnet 74, it outputs a detection signal. The reed switch provided on the upper side (hereinafter referred to as a determination reed switch (detecting body) 78) has a wire on the inner peripheral surface of the screw hole 44 of the nut 42 when the nut 42 is properly provided on the workpiece W. It is provided corresponding to the position of the magnet 74 when the piston member 66 stops due to contact with the 62 (hereinafter referred to as a normal stop position). When the determination reed switch 78 detects the magnet 74 that has arrived at the normal stop position, the determination reed switch 78 outputs the detection signal.

  The two reed switches 76 and 78 are electrically connected to a determination unit 80 that determines whether or not the nut 42 is properly provided on the workpiece W and whether or not the nut 42 is present. That is, when the determination unit 80 receives the detection signal from the start point reed switch 76, the determination unit 80 recognizes that the piston member 66 is at the lower limit position. When the detection signal is continuously received from the determination reed switch 78, the determination unit 80 determines that the nut 42 is properly provided on the workpiece W. Further, the determination unit 80 is set to determine that a missing part or a position shift of the nut 42 has occurred when an instantaneous (pulse-like) detection signal is received from the determination reed switch 78.

(Operation of Example)
Next, the operation of the nut detection device 30 according to the embodiment will be described with reference to an example in which the nut detection device 30 is used in a component (workpiece) welding process.

  First, a case where the nut 42 is welded to an appropriate position of the workpiece W will be described. The nut 42 provided on the workpiece W is welded to a predetermined position of the workpiece W in advance by arc welding or the like in the nut welding process. The nut detection device 30 is exposed from below the workpiece W by a movement control device (not shown), and the pin 34 is inserted into the through hole c of the workpiece W. When the flange surface 52 of the pin 34 comes into contact with the lower surface of the workpiece W, the movement control device stops the insertion of the pin 34. At this time, even if the pin 34 is displaced from the center of the screw hole 44 of the nut 42 and inserted, the determination unit 80 does not cause an erroneous determination. That is, if the pin 34 can be inserted into the screw hole 44 of the nut 42, the pin 34 can be determined accurately without being accurately inserted from the center of the screw hole 44, and the nut detection device 30 by the movement control device can be determined. The advanced control is unnecessary, and the cost can be reduced. When the pin 34 is inserted into the screw hole 44, the outlet / outlet 60 of the pin 34 faces the inner peripheral surface of the screw hole 44 of the nut 42 (see FIG. 2A). Further, when the pin 34 is inserted into the through hole c of the workpiece W, the pin 34 is fitted into the through hole c and the workpiece W is positioned.

  Next, the drive source is activated to supply air into the cylinder 36, and the piston member 66 located at the lower limit position is moved upward. Then, the wire 62 moves upward together with the piston member 66, and the distal end portion 64 of the wire 62 rises in the conduction hole 56 of the pin 34. Further, when the wire 62 is raised, the wire 62 is bent sideward (screw hole 44 side) along the curved portion of the conduction hole 56 and moved obliquely upward toward the side surface of the pin 34 (insertion portion 48). . As shown in FIG. 2B, when the distal end portion 64 of the wire 62 reaches the outlet 60, the distal end portion 64 comes into contact with the inner peripheral surface of the screw hole 44. Then, the drive source is stopped, the movement of the piston member 66 is stopped, and the movement of the wire 62 is also stopped. At this time, the magnet 74 provided on the plate portion 72 of the piston member 66 stops at the normal stop position, and the determination reed switch 78 detects the magnet 74. Then, since the determination reed switch 78 continues to detect the magnet 74, the switch 78 continuously transmits a detection signal to the determination unit 80, and the determination unit 80 has the nut 42 properly provided on the workpiece W. Is determined.

  When the determination by the determination unit 80 is completed, the drive source is activated, the air in the cylinder 36 is exhausted, the piston member 66 is lowered together with the wire 62, and the distal end portion 64 of the wire 62 is drawn into the conduction hole 56. . When the magnet 74 reaches the lower limit position and the start point reed switch 76 detects the magnet 74, the drive source stops and the movement of the piston member 66 is terminated. The workpiece W is welded to another workpiece W while being positioned on the pin 34. That is, according to the nut detection device 30 according to the embodiment, the workpiece W can be positioned together with the determination of the shortage of the nut 42, etc., so that no additional jig for positioning the workpiece W is required, and the cost is reduced. Can be made inexpensive.

  Next, a case where the nut 42 is not provided on the workpiece W (a missing part of the nut 42) will be described. Similarly to the above, the nut detection device 30 is faced from below the workpiece W, and the pin 34 is inserted into the through hole c of the workpiece W. However, as shown in FIG. 3, since the nut 42 does not exist in the workpiece W, the outlet / outlet 60 of the pin 34 is exposed to the outside. When the piston member 66 rises in this state, the tip end portion 64 of the wire 62 protrudes outward from the outlet 60 of the pin 34, and the wire 62 rises until the connecting portion 68 contacts the upper portion of the slide hole 38. Accordingly, the magnet 74 passes through the normal stop position, the determination reed switch 78 instantaneously detects the magnet 74, and a pulse-like detection signal is transmitted to the determination unit 80. Receiving this, the determination unit 80 determines that the nut 42 is abnormal, and a missing part of the nut 42 is detected.

  Next, a case where the nut 42 is provided so as to be shifted from an appropriate position of the workpiece W (position shift) will be described. In this case, as shown in FIG. 4, even if the pin 34 is to be inserted into the through hole c of the workpiece W, the tapered portion 50 of the pin 34 abuts against the nut 42 and further insertion is prevented. Accordingly, the through / outlet 60 of the pin 34 does not face the screw hole 44 of the nut 42 and is exposed to the outside below the workpiece W. When the piston member 66 rises in this state, the tip end portion 64 of the wire 62 protrudes outward from the outlet 60. Accordingly, since the magnet 74 passes through the normal stop position, the determination reed switch 78 instantaneously detects the magnet 74. Then, the determination unit 80 receives a pulse-like detection signal from the determination reed switch 78, and the determination unit 80 determines that the nut 42 is abnormal. Thereby, the position shift of the nut 42 can be detected.

  As described above, according to the nut detection device 30 according to the embodiment, it is possible to accurately detect a missing part or a positional deviation of the nut 42 without accurately inserting the pin 34 from the center of the screw hole 44 of the nut 42. it can. Moreover, since the workpiece | work W can be positioned with the pin 34, the workpiece | work W can be welded, determining the lack of the nut 42 etc. Therefore, it is not necessary to separately provide a jig for positioning the workpiece W, and the cost can be reduced. In the nut detection device 30 according to the embodiment, since the wire-like wire 62 is configured to move through the conduction hole 56, even if dust or the like is clogged in the conduction hole 56, the wire 62 causes the dust to go to the outside. It can discharge | release and it can suppress that a failure and malfunction of an apparatus arise.

32 device main body, 34 pins, 42 nut, 44 screw hole, 56 conduction hole 62 wire, 64 tip, 74 magnet (detected body)
78 Judgment reed switch (detector), 80 Judgment part, c Through hole, W Workpiece

Claims (1)

For the workpiece (W) in which the through hole (c) is formed, whether or not the nut (42) is properly provided at a position where the screw hole (44) is aligned with the through hole (c), and the nut ( 42) a nut detection device for determining the presence or absence of
A pin (34) that is provided at the tip of the apparatus body (32), is inserted into and removed from the through hole (c) of the workpiece (W), and positions the workpiece (W) when inserted into the through hole (c). )When,
A conduction hole (56) drilled to penetrate the pin (34) from the device body (32) side to the side facing the work (W) with the pin (34) inserted through the through hole (c). )When,
A wire that is inserted into the conduction hole (56) from the device main body (32) side and is reciprocally movable to the device main body (32), and the tip portion (64) can protrude and retract from the side surface of the pin (34) 62) and
A detected object (74) that reciprocates with the wire (62);
With the pin (34) facing the screw hole (44) of the nut (42) properly provided on the work (W), the wire (62) is connected to the tip (64) of the pin (34). The object to be detected is provided corresponding to the stop position of the object to be detected (74) when the tip part (64) contacts the inner surface of the screw hole (44) by moving in a direction protruding from the side surface. A detection body (78) capable of detecting (74);
And a determination unit (80) for determining whether or not the nut (42) is properly provided on the workpiece (W) based on a detection signal of the detection body (78) and whether or not the nut (42) is present. A nut detector characterized by that.

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