JP5570274B2 - Opening and closing chuck - Google Patents

Description

  The present invention relates to an opening / closing chuck for gripping a workpiece.

  When transporting workpieces in industrial facilities or the like, industrial robots are widely used, and these industrial robots grip a workpiece by an open / close chuck attached to an arm. As such an open / close chuck, for example, Patent Document 1 proposes one that operates by an air cylinder. The open / close chuck includes a cylinder chamber and a piston that moves in the cylinder chamber, and a pair of gripping members for gripping a workpiece are connected to the piston via a link mechanism. When air is supplied to the rear end side of the cylinder chamber, the open / close chuck moves the piston forward in the cylinder chamber, and the pair of gripping members move away from each other. On the other hand, when air is supplied to the distal end side of the cylinder chamber, the piston moves backward in the cylinder chamber, and the pair of gripping members move in directions approaching each other. The open / close chuck grips the workpiece to be conveyed by opening and closing the pair of gripping members in this way.

JP 2000-141265 A

  By the way, the open / close chuck as described above detects the opening / closing operation of the pair of gripping members by detecting the position of the piston by a magnetic sensor attached inside and a permanent magnet attached to the outer peripheral surface of the piston. . However, such a detection mechanism can only indirectly detect the position of the gripping member based on the position of the piston, and it is difficult to accurately detect whether the gripping member actually grips the workpiece. There is a problem that there is.

  Therefore, an object of the present invention is to provide an open / close chuck capable of accurately detecting gripping of a workpiece.

  The open / close chuck according to the present invention is an open / close chuck for gripping a work by a claw, and is configured to slide on the guide rail and the guide member. A first and a second slider installed and capable of attaching a claw; a drive source for sliding the first and second sliders so that the first and second sliders are separated from or approach each other; and The guide member includes a strain sensor attached at a position where strain is generated when the claws attached to the first and second sliders grip the workpiece.

  When the opening / closing chuck grips the workpiece with the claws attached to the first and second sliders, a moment acts on the guide member that contacts the first and second sliders by the reaction force from the workpiece, Distortion occurs in the guide member. This strain is detected by a strain sensor attached to the guide member. As described above, the opening / closing chuck can detect the distortion of the guide member that occurs when the claws attached to the first and second sliders actually grip the workpiece, and thereby grip the workpiece. Can be accurately detected. In addition, this open / close chuck has a strain sensor attached to the guide member, so that the size of the claw can be reduced, and when the claw is worn out due to wear or when the claw is replaced due to wear or depending on the work to be gripped. The strain sensor is not affected.

  In the guide member of the open / close chuck, when the claw attached to the first and second sliders grips the workpiece, the strain generated on the surface opposite to the surface on which the first and second sliders are installed is the other part. It becomes larger compared to the strain generated in For this reason, the strain sensor is preferably attached to the opposite surface. Thereby, the strain sensor can reliably detect the strain, and the gripping of the workpiece can be detected more accurately.

  Further, in the guide member of the opening and closing chuck, when the claws attached to the first and second sliders grip the workpiece, the sliding points of the first and second sliders pass through the center points of the first and second sliders. The strain generated at the position where the surface orthogonal to the moving direction and the surface of the guide member intersect with each other is larger than the strain generated in other portions. For this reason, it is preferable that at least a part of the strain sensor is attached to the position. Thereby, the strain sensor can reliably detect the strain, and the gripping of the workpiece can be detected more accurately.

  The open / close chuck may be a cylinder mechanism in which a drive source includes a cylinder chamber and a piston installed in the cylinder chamber so as to be capable of reciprocating.

  In the opening / closing chuck, the first and second sliders may be connected to a piston of the cylinder mechanism via a link mechanism. The link mechanism transmits the movement of the piston to the first and second sliders so that the reciprocating direction of the piston is orthogonal to the sliding direction of the first and second sliders. Thereby, the first and second sliders can be slid in a direction orthogonal to the reciprocating direction of the piston.

  According to the present invention, it is possible to accurately detect gripping of a workpiece.

1 is an exploded perspective view of an open / close chuck according to an embodiment of the present invention. It is a top view of the guide member of the opening-and-closing chuck which concerns on one Embodiment of this invention. It is a front fragmentary sectional view of the opening-and-closing chuck concerning one embodiment of the present invention. It is a displacement distribution map of the opening and closing chuck in one embodiment of the present invention.

  Hereinafter, an embodiment of an open / close chuck according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the open / close chuck 1 according to this embodiment is attached to a guide member 2, first and second sliders 3 a and 3 b installed so as to slide on the guide member 2, and the guide member 2. The strain sensor 4 is provided. The opening / closing chuck 1 includes a casing 5 having a built-in cylinder mechanism for driving the first and second sliders 3a and 3b.

  As shown in FIG. 1, the guide member 2 is for guiding the first and second sliders 3a and 3b, and a concave guide rail 21 extending in the horizontal axis direction is formed on the upper surface. A track groove 22 is formed on the inner wall of the guide rail 21 to guide a ball group of a ball bearing described later. As shown in FIG. 2, the guide member 2 has first and second elongated holes 23 a and 23 b that are long in the horizontal axis direction on the bottom surface of the guide rail 21.

  As shown in FIG. 1, the first and second sliders 3 a and 3 b are installed on the guide member 2 so as to slide along the guide rail 21. The first and second sliders 3 a and 3 b incorporate ball bearings, and a part of the ball group of the ball bearings is exposed on the surface facing the inner wall of the guide rail 21. As the ball group rolls along the raceway groove 22 of the guide rail 21, the first and second sliders 3 a and 3 b smoothly slide on the surface of the guide member 2. Further, screw holes 31 are formed in the first and second sliders 3a and 3b, and claws (not shown) made of metal, resin, or the like for gripping the workpiece are attached to the screw holes 31. It is done.

  As shown in FIG. 3, the first and second sliders 3a and 3b are connected to first and second link mechanisms 6a and 6b described later by first and second connecting members 14a and 14b. . The upper ends of the first and second connecting members 14a and 14b protrude from the upper surfaces of the first and second sliders 3a and 3b, and the lower ends of the first and second connecting members 14a and 14b are described later via the first and second elongated holes 23a and 23b. The casing 5 extends into the storage chamber 52. The first connecting member 14a has an upper end fixed to the first slider 3a by press fitting or the like, and has a first insertion pin 141a at the lower end. The first connecting member 14a is connected to the first link mechanism 6a by inserting the first insertion pin 141a into an insertion portion 63 of the first link member 61a described later. Similarly, the upper end portion of the second connecting member 14b is fixed to the second slider 3b by press-fitting or the like, and a second insertion pin (not shown) at the lower end portion of the second link member 61b described later. It is connected to the second link mechanism 6b by being inserted into an insertion portion (not shown).

  The strain sensor 4 is attached to the lower surface of the guide member 2 and the center in the horizontal axis direction, and is electrically connected to a connector (not shown) connected to the connector connecting portion 41. The strain sensor is preferably a high-sensitivity sensor that can detect even a minute strain. For example, a rectangular stainless steel is used as a substrate, and four strain gauges made of a semiconductor silicon thin film are formed at the center of the substrate. It is preferable that the strain sensor has a mouth shape and a bridge circuit.

  As shown in FIG. 1, the casing 5 has a flange portion 51, and the guide member 2 is fixed on the flange portion 51 with screws or the like. A housing chamber 52 having an open upper end is formed inside the casing 5, and first and second link mechanisms 6 a and 6 b described later are housed in the housing chamber 52. Further, as shown in FIG. 3, a cylinder chamber 53 that communicates with the storage chamber 52 and extends in the vertical axis direction is formed inside the casing 5. The cylinder chamber 53 has a small diameter portion 531 and a large diameter portion 532, and a step 533 is defined by the small diameter portion 531 and the large diameter portion 532. An annular groove is formed in the small diameter portion 531 along the inner peripheral surface, and the first packing 7 is accommodated in the annular groove. A sealing member 8 is attached to the lower end of the cylinder chamber 53. The sealing member 8 has an O-ring 81 accommodated in an annular groove formed along the outer peripheral surface, and hermetically seals the rear end portion of the cylinder chamber 53.

  As shown in FIGS. 1 and 3, the casing 5 has first and second supply holes 10 and 11 formed on the front surface, and third and fourth supply holes 12 and 13 on the right side surface. Is formed. The first to fourth supply holes 10 to 13 communicate with the cylinder chamber 53 so that air can be supplied into the cylinder chamber 53, and the air sent from the first and third supply holes 10 and 12 is The air supplied between the piston head 541 and the sealing member 8 and sent from the second and fourth supply holes 11 and 13 is configured to be supplied between the piston head 541 and the step 533.

  A piston 54 is slidably installed in the cylinder chamber 53 as shown in FIG. More specifically, the piston 54 has a piston head 541 and a piston rod 542 connected to the piston head 541. The piston head 541 is formed in a cylindrical shape and is slidable with respect to the inner wall of the large-diameter portion 532 in the cylinder chamber 53. The piston head 541 is formed with an annular groove along the outer peripheral surface, and is in airtight contact with the inner wall of the large-diameter portion 532 by the second packing 9 accommodated in the annular groove. The piston rod 542 passes through the small diameter portion 531 of the cylinder chamber 53, and the tip portion projects into the storage chamber 52. The piston rod 542 is slidable with respect to the inner wall of the small diameter portion 531 and is in airtight contact with the first packing 7 of the small diameter portion 531. A piston cover 544 is attached to the piston rod 542, and the piston cover 544 comes to the front of the piston 54 by contacting the step 533 of the cylinder chamber 53 when the piston 54 slides forward in the cylinder chamber 53. Regulate the movement of A magnet 545 is accommodated between the leather cover 544 and the piston head 541, and the position of the piston 541 can be detected by a proximity sensor (not shown) installed in the magnet 545 and the cylinder chamber 53. . The piston rod 542 has a third insertion pin 543 formed at the tip, and the third insertion pin 543 is used to insert first and second link members 61a and 61b described later in the storage chamber 52. The part 63 is inserted.

  As shown in FIGS. 1 and 3, the first and second link mechanisms 6a and 6b have first and second link members 61a and 61b, and the first and second link members 61a. , 61b are rotatably attached to a first fulcrum pin 62a and a second fulcrum pin (not shown), respectively. The first and second link members 61a and 61b are formed in a substantially L shape, and have substantially U-shaped insertion portions 63 at both ends. The first link member 61 a is connected to the piston 54 by inserting the third insertion pin 543 at the tip of the piston rod 542 into the insertion portion 63 on the lower end side, and is connected to the insertion portion 63 on the upper end side. The first insertion pin 141a of 14a is inserted to be connected to the first connection member 14a. Similarly, the second link member 61b has an upper end press-fit portion (not shown) connected to the third insertion pin 543 of the piston rod 542, and a lower end press-fit portion (not shown) as the second connecting member. 14b is connected to a second insertion pin (not shown).

  Next, the operation | movement at the time of hold | gripping the workpiece | work of the opening / closing chuck | zipper 1 comprised as mentioned above is demonstrated. In the present embodiment, since the first and second supply holes 10 and 11 of the casing 5 are used, the first and second supply are performed via a switching valve, a joint, a tube, and the like that can switch the air flow direction. An air supply source (not shown) is connected to the holes 10 and 11, and the third and fourth supply holes 12 and 13 are sealed with screws or the like. In addition, the 3rd supply hole 12 may be used instead of the 1st supply hole 10, and both the 1st and 3rd supply holes 10 and 12 can also be used. Moreover, the 4th supply hole 13 may be used instead of the 2nd supply hole 11, and both the 2nd and 4th supply holes 11 and 13 can also be used.

  First, air is supplied into the cylinder chamber 53 from the first supply hole 10 to separate the first and second sliders 3a and 3b from each other. More specifically, when air is supplied from the air supply source into the cylinder chamber 53 through the first supply hole 10, the lower surface of the piston head 541 is pushed by this air, and the piston 54 moves forward in the cylinder chamber 53. And move. At this time, the air existing between the piston head 541 and the step 533 is pushed by the piston head 541 and discharged from the second supply hole 11. When the piston 54 moves forward, the first link member 61a connected to the tip of the piston rod 542 rotates around the first fulcrum pin 62a in the clockwise direction in FIG. Thereby, the first connecting member 14a connected to the first link member 61a moves outward in the first long hole 23a, and the first slider 3a connected to the first connecting member 14a. Slides outward on the guide rail 21 of the guide member 2. On the other hand, the second link member 61b rotates counterclockwise in FIG. 3 around a second fulcrum pin (not shown). Thus, the second connecting pin 14b connected to the second link member 61b moves outward in the second long hole 23b, and the second slider 3b connected to the second connecting member 14b. Slides outward on the guide rail 21.

  Next, a work is disposed between the first slider 3 a and the second slider 3 b that are separated from each other, and air is supplied into the cylinder chamber 53 through the second supply hole 11 to thereby supply the first and second sliders. 3a and 3b are brought close to each other. More specifically, when air is supplied from the air supply source into the cylinder chamber 53 via the second supply hole 11, the upper surface of the piston head 541 is pushed by this air, and the piston 54 moves rearward. At this time, air existing between the piston head 541 and the sealing member 8 is pushed by the piston head 541 and discharged from the first supply hole 10. When the piston 54 moves rearward, the first link mechanism 6a connected to the piston rod 542 rotates counterclockwise in FIG. 3 about the first fulcrum pin 62a. Accordingly, the first connecting member 14a moves inward in the first long hole 23a, and the first slider 3a slides inward on the guide rail 21. On the other hand, the second link mechanism 6b rotates clockwise in FIG. 3 around a second fulcrum pin (not shown). Accordingly, the second connecting pin 14b moves inward in the second long hole 23b, and the second slider 3b slides inward on the guide rail 21. In this way, the first and second sliders 3a and 3b are brought close to each other, and the work is gripped by the claws attached to the first and second sliders 3a and 3b.

  As described above, when the workpiece is gripped by the claws attached to the first and second sliders 3a and 3b, a reaction force from the workpiece acts on the claws. By this reaction force, a moment acts on the guide member 2 in contact with the first and second sliders 3a and 3b, and the guide member 2 is distorted in the horizontal and vertical axes. This strain is detected by a strain sensor 4 attached to the lower surface of the guide member 2 and the center in the horizontal axis direction.

  As described above, according to the open / close chuck 1 of the present embodiment, the strain sensor 4 is generated in the guide member 2 when the workpiece is actually gripped by the claws attached to the first and second sliders 3a and 3b. Strain can be detected. Thereby, the opening / closing chuck 1 can accurately detect whether or not the first and second sliders have gripped the workpiece.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the above embodiment, the strain sensor 4 is attached to the center and the lower surface in the horizontal axis direction of the guide member 2, but is not limited to this as long as it is attached to a position where distortion occurs when a workpiece is gripped. For example, you may attach to the upper surface of a guide member, the front surface, and the back surface.

  In the above embodiment, air is supplied from the first and second supply holes 10 and 11 into the cylinder chamber 53 to operate the piston 54. However, the first and second supply holes 10 and 11 are operated. , And an air supply source is connected to the third and fourth supply holes 12 and 13 so that air can be supplied from the third and fourth supply holes 12 and 13.

  In the above embodiment, the first and second link mechanisms 6a and 6b cause the piston 54 to reciprocate so that the first and second sliders 3a and 3b slide in a direction perpendicular to the moving direction of the piston 54. The movement has been converted, but the present invention is not limited to this. The piston and the first and second sliders are connected so that the movement direction of the piston and the movement directions of the first and second sliders are parallel to each other. May be.

  In the above embodiment, the driving source of the first and second sliders 3a, 3b is an air cylinder mechanism, but is not limited to this. For example, a hydraulic cylinder mechanism, an electric cylinder mechanism, etc. Also good.

  Moreover, in the said embodiment, although the 1st and 2nd slider 3a, 3b had the nail | claw which can be removed, if it can hold | grip a workpiece | work, it will not be limited to this, For example, the 1st and 2nd The slider and the claw may be formed integrally.

  The following examples illustrate the present invention more specifically.

  The following analysis was performed using the open / close chuck 1 in FIG. The guide member 2 of the open / close chuck 1 was fixed to a rigid plate with four bolts. The pitch of the four bolts in the horizontal axis direction was 42.5 mm, and the pitch in the depth direction was 15 mm. The first and second sliders 3a and 3b are placed on the guide rail 21 of the guide member 2 fixed in this manner with an interval of 30 mm, and 20 mm upward from the center of the track groove 22 formed in the guide rail 21. At the position, a force of 25N was applied outward to the claws of the first and second sliders 3a and 3b, and the displacement of each part of the guide member 2 at this time was measured. As a result, it has been found that the guide member 2 has a slight displacement in the vertical axis direction, and in particular, the displacement in the central portion in the horizontal axis direction is relatively large. Of the displacement of the central portion of the guide member 2 in the horizontal axis direction, the displacement at the center of the lower surface was 0.00028 mm, the displacement at the front end of the lower surface was 0.00025 mm, and the displacement at the back was 0.00022 mm (FIG. 4).

  As described above, when the workpiece is gripped by the opening / closing chuck 1, a relatively large displacement occurs in the central portion in the horizontal axis direction of the guide member 2, so that the strain sensor 4 is attached to the central portion in the horizontal axis direction of the guide member 2. Is preferred. Furthermore, since the large displacement occurs particularly in the lower surface in the central portion in the horizontal axis direction, the strain sensor 4 is more preferably attached to the central portion in the horizontal axis direction and the lower surface of the guide member 2.

2 Guide member 21 Guide rail 3a First slider 3b Second slider 4 Strain sensor 53 Cylinder chamber 54 Piston
6a First link mechanism 6b Second link mechanism

Claims (5)

An open / close chuck that grips a workpiece with a claw,
A guide member having a guide rail;
A first slider and a second slider which are installed to slide on the guide rail and to which a claw can be attached;
A drive source for sliding the first and second sliders such that the first and second sliders are spaced apart from or approaching each other;
In the guide member, a strain sensor attached at a position where distortion occurs when the claws attached to the first and second sliders grip the workpiece;
Opening and closing chuck comprising.   The open / close chuck according to claim 1, wherein the strain sensor is attached to a surface of the guide member opposite to a surface on which the first and second sliders are installed.   The strain sensor passes through the center point of the first and second sliders when the claws attached to the first and second sliders grip the workpiece, and the sliding direction of the first and second sliders The opening / closing chuck according to claim 1, wherein at least a part is attached at a position where a surface orthogonal to the surface intersects with a surface of the guide member.   The open / close chuck according to any one of claims 1 to 3, wherein the drive source is a cylinder mechanism having a cylinder chamber and a piston installed in the cylinder chamber so as to be reciprocally movable. The first and second sliders are connected to one end of the piston via a link mechanism,
The link mechanism transmits the movement of the piston to the first and second sliders so that the reciprocating direction of the piston and the sliding direction of the first and second sliders are orthogonal to each other. Opening and closing chuck.

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