JP2012218112A - Robot hand including floating mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot hand including a floating mechanism, which is inexpensive, has high flexibility and can be positioned in both horizontal and vertical directions with high accuracy.SOLUTION: The robot hand 10 includes: a first linear guide 20 attached to a tip end part of a robot arm 12 and movable in a first axis line direction; a second linear guide 26 movably provided in the first linear guide 20 and movable in a second axis line direction; a round bearing 32 movably provided in the second linear guide 26 and rotatable around a third axis line; and a holding mechanism 34 connected to the bearing 32. The first to third axis lines form angles of not zero angle to each other and the robot hand 10 is used while both first and second axis lines are made horizontal.

Description

  The present invention relates to a robot hand equipped with a floating mechanism, and more particularly to a robot hand equipped with a floating mechanism that can be accurately positioned at a predetermined position while holding a workpiece.

  When a robot hand holds a workpiece and positions it at a predetermined location, a floating mechanism that holds the workpiece in a floating state may be employed. For example, in Patent Document 1, one of a locating pin and a fitting portion having a locating hole into which the locating pin is fitted is provided on the base member, the other is provided on a shaft that moves up and down together with the suction pad, and the locating pin is fitted in the locating hole. A workpiece transfer device having an actuator that forms a rigid state and a detached floating state is disclosed.

  Further, Patent Document 2 includes a plurality of clampers that grip a workpiece and a plurality of air cylinders that respectively drive the clampers, and when the workpiece is inserted into a jig, the pressure of the air cylinder is made lower than that during workpiece conveyance. A robot hand device is disclosed.

  Further, Patent Document 3 discloses that the floating board 10 is accommodated between the extending portion 9a of the support plate 9 and the guide wall 4a of the support frame 4, and a ball plunger 11 is interposed between them to freely move in the horizontal direction. A robot hand is disclosed.

Japanese Patent Laid-Open No. 2001-293681 JP 2000-6078 A Japanese Patent Laid-Open No. 6-182689

  In the floating mechanism in the vertical direction as described in Patent Document 1 and the floating mechanism in one direction as described in Patent Document 2, the floating direction is limited. It is difficult. In addition, in the type supported by the ball plunger as described in Patent Document 3, the floating portion is likely to rattle in the vertical direction, and accurate positioning may be difficult depending on the application.

  Accordingly, an object of the present invention is to provide a robot hand provided with a floating mechanism that is inexpensive, has a high degree of freedom, and can be positioned with high precision in both the horizontal and vertical directions.

  In order to achieve the above object, the invention according to claim 1 is a robot hand equipped with a floating mechanism, which is attached to the tip of the robot arm, and is a first attached to the tip of the robot arm. , A first linear guide having a first slide portion movably provided in the direction of the first axis on the first base portion, a second base portion, and the second base A second slide portion movably provided in the direction of the second axis, and the first slide portion so that the second axis forms an angle other than zero degrees with the first axis. A second linear guide to which the second base portion is attached; a third base portion; and a rotating portion provided on the third base portion so as to be rotatable around a third axis, The angle at which the third axis is not zero degrees with respect to the first axis A circular bearing in which the third base portion is attached to the second slide portion so that the third axis forms an angle with the second axis that is not zero degrees; and And a holding mechanism connected to each other, and a robot hand that is used in a state where both the first axis and the second axis are horizontal.

  According to a second aspect of the present invention, in the robot hand according to the first aspect, the first linear guide, the second linear guide, and the circular bearing are springs or fixedly arranged on respective base portions. Provided are robot hands each provided with a centering mechanism for holding the slide part or the rotating part in the vicinity of the center of each movable range by supporting each slide part or the rotating part via a cylinder.

  According to a third aspect of the present invention, in the robot hand according to the first or second aspect, the first linear guide, the second linear guide, and the circular bearing are fixedly disposed on a base portion, respectively. Thus, a robot hand provided with a lock mechanism for fixing the slide part or the rotation part by inserting a pin-like or wedge-like member into each slide part or the rotation part is provided.

  According to the present invention, by combining two linear guides at an angle other than zero degrees and connecting a bearing to the linear guide, a floating mechanism that can move in parallel and has no play can be provided at low cost.

  By providing a centering mechanism in the first linear guide, the second linear guide, and the bearing, it is possible to prevent the workpiece from being undesirably displaced with respect to the robot arm in the floating state.

  By providing the first linear guide, the second linear guide, and the bearing with a lock mechanism, it is possible to stably carry the workpiece other than during workpiece positioning, move the robot hand when the workpiece is not held, or the like.

It is a figure which shows the robot hand which concerns on one Embodiment of this invention. It is a figure which shows the state by which the 1st and 2nd lock mechanism is cancelled | released. It is a figure which shows the state which the 1st and 2nd locking mechanism is act | operating. It is a figure which shows the state by which the 3rd locking mechanism is cancelled | released. It is a figure which shows the state which the 3rd locking mechanism is act | operating. It is a flowchart which shows the conveyance procedure of the workpiece | work using the robot hand which concerns on one Embodiment of this invention. It is a figure which shows the state which is carrying out the suction holding | maintenance of the workpiece | work on a pallet using a robot hand. It is a figure which shows the state which conveyed the workpiece | work attracted | sucked and held on the work table. It is a figure which shows the state which positioned the workpiece | work in the reference position on a work bench. It is a figure which shows the state which cancelled | released holding | maintenance of the workpiece | work and the robot hand was evacuated. It is a figure showing typically the 1st modification of a robot hand concerning the present invention. It is a figure which shows typically the 2nd modification of the robot hand which concerns on this invention.

  FIG. 1 is a diagram showing a configuration example of a robot hand 10 provided with a floating mechanism according to the present invention. The robot hand 10 is attached to the tip of the robot arm 12 of the robot (not shown), but is attached via a wrist 14 that is rotatably attached to the robot arm 12 as shown in the example. Also good. The robot hand 10 is movable in the direction of the first axis (here, X direction) to the first base portion 16 attached to the tip or wrist portion 14 of the robot arm 12 and the first base portion 16. The first linear guide 20 having the first slide portion 18 provided, the second base portion 22 attached to the first slide portion 18, and the direction of the second axis on the second base portion 22 A second linear guide 26 having a second slide portion 24 movably provided (here, a Y direction perpendicular to the X direction), and a third base portion 28 attached to the second slide portion 24. And a circular bearing having a rotating portion 30 provided on the third base portion 28 so as to be rotatable about a non-horizontal third axis (here, Z direction perpendicular to both the X direction and the Y direction). 32 and rotating part 30 It is connected, and a holding mechanism 34 that is capable of holding a work of a predetermined shape.

  In the present embodiment, the first, second and third axes are perpendicular to each other, but the present invention is not limited to this. In implementing the present invention, the second axis forms an angle other than zero degrees with the first axis, the third axis forms an angle other than zero degrees with the first axis, and the third axis forms the second axis. The first and second axes may be horizontal and the third axis may extend in a non-horizontal direction during use.

  The first linear guide 20 includes a first lock mechanism 36 that fixes the first slide portion 18 to the first base portion 16. Specifically, the first locking mechanism 36 has, for example, a pin-shaped or wedge-shaped movable member, and the first slide portion 18 is moved to the first slide by engaging the movable member with the first slide portion 18. It is possible to prevent movement with respect to the base portion 16 of the first embodiment. Further, the first linear guide 20 moves the first slide portion 18 to a predetermined position (for example, the first slide portion 18 of the first slide portion 18) with respect to the first base portion 16 when the first lock mechanism 36 is not operated. The first centering mechanism 38 is positioned near the center of the movable range.

  Similar to the first linear guide, the second linear guide 26 includes a second lock mechanism 40 that fixes the second slide portion 24 to the second base portion 22. Specifically, the second locking mechanism 40 has, for example, a pin-shaped or wedge-shaped movable member, and by engaging the movable member with the second slide portion 24, the second slide portion 24 is moved to the second position. It is possible to prevent the base portion 22 from moving. Further, the second linear guide 26 moves the second slide portion 24 with respect to the second base portion 22 at a predetermined position (for example, the second slide portion 24 of the second slide portion 24) when the second lock mechanism 40 is not operated. The second centering mechanism 42 is positioned near the center of the movable range.

  The circular bearing 32 includes a third lock mechanism 44 that prevents the rotation unit 30 from rotating with respect to the third base unit 28. Specifically, the third lock mechanism 44 has, for example, a pin-shaped or wedge-shaped movable member, and by engaging the movable member with the rotating portion 30, the rotating portion 30 is moved relative to the third base portion 28. To avoid moving. Further, the bearing 32 positions the rotating part 30 at a predetermined rotational angle position (for example, near the center of the movable range of the rotating part 30) with respect to the third base part 28 when the third lock mechanism 44 is not operated. A third centering mechanism 46 is provided.

  The holding mechanism 34 is configured to be able to hold a workpiece that is a conveyance target. In the illustrated example, the holding mechanism 34 sucks and holds a flat workpiece 50 (see FIGS. 7 to 10) (in the illustrated example). Eight) suction pads 52 are provided. The suction pad 52 is fluidly connected to a vacuum device or the like (not shown) via a pipe / tube 54 and the like fluidly connected to the suction pad 52, and can hold the workpiece by a suction force by vacuum. The holding mechanism 34 is not limited to such a vacuum suction type, and various types such as a gripping type using a clamping means and a magnetic force suction type using an electromagnet can be used.

  Next, the details of the above-described locking mechanism and centering mechanism will be described with reference to FIGS. 2 and 3, the first base portion 16 is shown as transparent for the sake of clarity, and members above the first base portion 16 are not shown. 4 and 5, for the sake of clarity, the disk-like member 55 substantially integrated with the third base portion 28 is shown as transparent, and members above the disk-like member 55 are not shown.

  As shown in FIGS. 2 and 3, the first locking mechanism 36 includes a first cylinder body 56 fixedly disposed on the second base portion 22 fixed to the first slide portion 18, and a first cylinder body 56. A first wedge-shaped member 58 movably attached to the cylinder body 56, and the first wedge-shaped member 58 engages with a first concave-shaped member 60 provided in the first base portion 16 to form a first The slide portion 18 and the second base portion 22 are fixed to the first base portion 16 (FIG. 3). On the other hand, the first centering mechanism 38 is a pair of springs configured to bias the first slide portion 18 in the movable direction (X direction) of the first slide portion 18 in the illustrated example and in directions opposite to each other. It is. Accordingly, when the first lock mechanism 36 is not operated (FIG. 2) and no external force is applied, a position where the urging forces of both springs are balanced (for example, near the center of the movable range of the first slide portion 18). The second base portion 22 is maintained in a so-called floating state.

  Similarly, the second lock mechanism 40 includes a second cylinder body 62 fixedly disposed on the third base portion 28 fixed to the second slide portion 24 (FIG. 1), and a second cylinder body 62. And a second wedge-shaped member 64 movably attached to the second wedge-shaped member 62. The second wedge-shaped member 62 engages with a second concave-shaped member 66 provided on the second base portion 22 to engage with the second slide portion. 24 and the 3rd base part 28 are fixed with respect to the 2nd base part 22 (FIG. 3). On the other hand, the second centering mechanism 42 is a pair of springs configured to bias the second slide portion 24 in the movable direction (Y direction) of the second slide portion 24 in the illustrated example and in opposite directions. It is. Therefore, when the second locking mechanism 40 is not operated (FIG. 2) and no external force is applied, a position where the urging forces of the two springs are balanced (for example, near the center of the movable range of the second slide portion 24). The third base portion 28 is maintained in a so-called floating state.

  As shown in FIGS. 4 and 5, the third locking mechanism 44 includes a third cylinder body 70 fixedly disposed on a substantially rectangular plate-like member 68 fixed to the rotating portion 30, and a third cylinder body. And a third wedge-shaped member 72 movably attached to 70, and the third wedge-shaped member 72 engages with a third concave-shaped member 74 provided in the rotating portion 30, thereby rotating the rotating portion 30 and the plate-like member. 68 is fixed to the third base portion 28 (FIG. 5). On the other hand, the third centering mechanism 46 includes a third main body 76 provided on the plate-like member 68, and a gripping portion 80 that grips a tab-like member 78 extending outward in the rotational radial direction from the rotating portion 30. The grip portion 80 is configured to be movable (generally in the X direction in the illustrated example) with respect to the third main body 76 so that the rotating portion 30 can rotate within a predetermined rotation angle range. Further, the third main body 76 includes an urging means such as a spring inside, and can hold the grip portion 80 at a predetermined position (for example, near the center of the movable range of the grip portion 80) when no external force is applied. It is like that. Therefore, when the third lock mechanism 44 is not operated (FIG. 4) and no external force is applied, the rotating unit 30 is maintained in a so-called floating state at a predetermined angular position.

  The first to third centering mechanisms have been described as using springs, but a cylinder such as an air cylinder or a hydraulic cylinder may be used instead of the springs.

  Hereinafter, the workpiece transfer / positioning operation using the robot hand 10 will be described with reference to the flowchart of FIG. 6 and FIGS. 7 to 10. In the illustrated embodiment, a substantially rectangular flat plate-like workpiece 50 placed on a pallet 82 disposed within the movable range of the robot arm 12 is held by the suction pad 52 of the robot hand 10, and a work not shown in the figure. In order to machine the workpiece 50 by a machine (not shown), the held workpiece 50 is positioned at a reference position on a work table 84 disposed in the vicinity of the machine tool and within the movable range of the robot arm 12. The case where it arranges is shown.

  First, as shown in steps S1 to S2 of FIG. 6 and FIG. 7, in a state in which the floating mechanism is locked (that is, in a state where all of the first to third locking mechanisms are operating), a predetermined position (FIG. In the example shown, the work 50 disposed on the pallet 82 is sucked and held by the holding mechanism 34.

  Next, the robot arm 12 is operated to move the workpiece 50 to a predetermined standby position (step S3). The standby position can be set as appropriate according to the application, but in the illustrated example, it may be above or obliquely above the work table 84 where the work 50 is to be placed.

  In the next step S4, it is determined whether or not the workpiece can be set, specifically, whether or not the workpiece 50 can be positioned on the work table 84. For example, when the machine tool is not yet ready for machining the workpiece 50, the workpiece 50 is maintained at the standby position until the preparation is completed.

  When the workpiece 50 can be set, as shown in FIG. 8, the process proceeds to step S5 where the floating mechanism is unlocked, that is, the first to third locking mechanisms are released. Normally, all of the first to third locking mechanisms are released, but depending on the application, only one or two of them may be unlocked. In the unlocked state, the above-described centering mechanism operates, and, for example, in the case of the first linear guide 20, the first slide portion 18 is positioned near the center of the operation range.

  In the next step S6, as shown in FIG. 9, the robot arm 12 is operated to position the workpiece 50 at the reference position. For example, a dam-like portion 86 having a shape that matches a part of the outer shape of the workpiece 50 is provided on the work table 84, and the workpiece 50 is moved by abutting the portion of the workpiece 50 against the dam-like portion. It is possible to accurately position the reference position on the work table 84.

  When the workpiece 50 is positioned at the reference position, the workpiece 50 is placed on the work table 84, that is, the workpiece is set (step S7). Here, a work fixing means (not shown) may be provided separately on the work table 84 or the machine tool so as to prevent the work 50 from unintentionally moving on the work table 84.

  Next, the suction pad 52 is deactivated, that is, the suction force is cut off (step S8), and the robot hand 10 is moved to a predetermined retreat position as shown in FIG. 10 (step S9). The retracted position can be set as appropriate according to the application. In the illustrated example, the retracted position is somewhat retracted from the workbench 84 to the robot body side, but a pallet (not shown) on which the workpiece to be held next is placed. )).

  Finally, the floating mechanism is again locked to hold and hold the next workpiece (step S10).

  FIG. 11 is a diagram schematically showing a first modification of the present invention. The difference from the above-described embodiment is that the first and second axes are not perpendicular to each other and that the holding mechanism 34 can cope with the case where the surface of the work table is inclined, for example. It is attached to the slant. As schematically illustrated in the top view of FIG. 11, the first axis 88 that is the moving direction of the first linear guide and the second axis 90 that is the moving direction of the second linear guide need to be perpendicular to each other. However, when the robot hand is used, it is sufficient that both are horizontal as shown in the side view. The third axis 92 that is the rotation axis of the rotating unit 30 is perpendicular to the first and second axes (that is, in the vertical direction), but the surface of the work table 84 on which the work 50 is to be placed is inclined. Depending on the case, the holding mechanism 34 may be attached obliquely to the rotating unit 30 so that the work 50 is held by the holding mechanism 34 in an inclined state.

  FIG. 12 is a diagram schematically showing a second modification of the present invention. The point that the first and second axes are not perpendicular to each other is the same as in the first modified example, but instead of the holding mechanism 34 being attached obliquely to the rotating unit 30, the third base 28 is a work table 84. Therefore, the rotating portion 30 is also attached obliquely to the third base portion 28. As a result, the third axis 92 becomes the first and second axes. It is the composition which is not perpendicular to. As described above, the third axis 92 does not need to be perpendicular to the first and second axes, and can be configured to have an angle other than 90 degrees other than zero degrees depending on the application.

DESCRIPTION OF SYMBOLS 10 Robot hand 12 Robot arm 14 Wrist part 20 1st linear guide 26 2nd linear guide 32 Bearing 36 1st locking mechanism 38 1st centering mechanism 40 2nd locking mechanism 42 2nd centering mechanism 44 3rd Lock mechanism 46 Third centering mechanism 50 Work 52 Suction pad 82 Pallet 84 Work table

Claims (3)

A robot hand equipped with a floating mechanism attached to the tip of the robot arm,
A first linear guide having a first base portion attached to a tip portion of the robot arm, and a first slide portion movably provided in the direction of the first axis on the first base portion;
A second base portion, and a second slide portion movably provided in the direction of the second axis on the second base portion, and the second axis is not zero degrees with respect to the first axis A second linear guide having the second base portion attached to the first slide portion so as to form an angle;
A third base portion, and a rotation portion provided on the third base portion so as to be rotatable about a third axis, wherein the third axis forms an angle other than zero with the first axis. A circular bearing in which the third base portion is attached to the second slide portion so that the third axis forms an angle other than zero with the second axis;
A holding mechanism connected to the rotating part,
A robot hand which is used in a state where both the first axis and the second axis are horizontal.   The first linear guide, the second linear guide, and the circular bearing support the slide part or the rotary part via a spring or a cylinder fixedly arranged on the base part, thereby the slide. The robot hand according to claim 1, further comprising a centering mechanism that holds the rotating portion or the rotating portion near the center of each movable range.   Each of the first linear guide, the second linear guide, and the circular bearing is inserted into a pin-shaped or wedge-shaped member by inserting a pin-shaped or wedge-shaped member into each slide portion or rotating portion by a cylinder fixedly disposed on the base portion. The robot hand according to claim 1, further comprising a lock mechanism for fixing the slide part or the rotating part.

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