JP2017019077A - Gripping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripping device capable of gripping a workpiece having a wide diameter and gripping a cross-sectional shape of the inner peripheral surface in a state of a circle having high roundness.SOLUTION: A gripping device 1 for gripping a workpiece W includes: a rotating body 21; and a sheet member 24 which is wound up around the surface of the rotating body 21 or is wound out from the surface of the rotating body 21 by rotation of the rotating body 21. In the gripping device 1, the sheet member 24 has flexibility, the sheet member 24 has a cylindrical gripping section 313 and is wound out from the rotating body 21 or is wound up around the rotating body by the rotation of the rotating body 21 so as to enlarge or reduce the diameter of the gripping section 313, and the gripping section 313 abuts on an inner peripheral surface or an outer peripheral surface of a workpiece W so as to grip the workpiece W.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a gripping device that grips a workpiece.

  Examples of the cylindrical workpiece include a fixing member such as a fixing belt and a fixing sleeve used in the image forming apparatus. The fixing member has various sizes depending on the model of the image forming apparatus, and a gripping device that can grip a workpiece having various inner diameters is required.

  Examples of such a gripping device include those disclosed in Patent Document 1 (Japanese Patent No. 5512248) and Patent Document 2 (Japanese Patent Laid-Open No. 07-163934).

  As shown in FIG. 26, the gripping device 100 of Patent Document 1 includes a first picker 101 and a second picker 111 connected to each other. The first picker 101 includes a cylindrical first hard base 102 and a first tube 103 provided around the outer periphery of the first hard base 102. The second picker 111 has a cylindrical second hard base 112 and a second tube 113.

  By individually supplying air from the air passages provided in the respective hard bases, the respective tubes are individually expanded in diameter, and abut against the inner peripheral surface of the outer work W to grip the tubes. (In FIG. 26, air is supplied to the second tube 113 by the air passage 114, the diameter of the second tube 113 is increased, and the workpiece W is gripped).

  As shown in FIG. 27, the gripping device 150 of Patent Document 2 includes a base flange 151 that can be moved up and down, a rod 152, a guide that is fixed to the base flange 151 at one end and provided at the lower end of the rod 152 at the other end. And a plurality of leaf springs 154 fixed to 153.

  As the base flange 151 moves up and down, one end of the leaf spring 154 fixed to the base flange 151 moves up and down accordingly, and the other end is fixed to the guide 153 and does not move from that position. Therefore, when the base flange 151 is lowered in the direction of the arrow A1, the leaf spring 154 is bent outward as shown by a two-dot chain line portion in the drawing, and comes into contact with and grips the inner peripheral surface of the workpiece W. As described above, the leaf spring 154 is bent in accordance with the diameter of the inner peripheral surface of the workpiece W, whereby workpieces having different diameters can be gripped.

  As a method similar to the gripping device of Patent Document 2, an annular elastic body is provided between a fixed base (guide) and an elevating base (base flange), and the work is performed while elastically deforming the annular elastic body as the elevating base moves up and down. There is already an elastic-compression-type gripping device that grips the device, for example, Patent Document 3 (Japanese Patent No. 2800448).

  In addition, there are three claws for gripping the inner surface of the workpiece, and by adjusting the opening of the three claws, a three-claw gripping device that grips workpieces with a wide diameter, and gripping the inner surface side by vacuum suction Such a suction-type gripping device is also included.

  As in Patent Document 1, in the balloon method in which air is fed from the inside and the tube is expanded to grip the workpiece, the amount of expansion of the tube increases as the inner diameter of the workpiece increases, and the gripping force of the workpiece and the durability of the tube are increased. A degradation problem occurs. In Patent Document 1, the range of the diameter of a work that can be gripped can be expanded by using two types of tubes, but the application range is limited, and a wide range of work cannot be gripped.

  In addition, in the gripping device of the outward bending method of the sheet-like member (plate spring) as in Patent Document 2, it is difficult to control the bending state of the plate spring, and the cross section of the inner peripheral surface of the workpiece to be gripped However, since the portion gripped by the leaf spring becomes a protruding polygon, it is difficult to grip in a circular shape.

  In the gripping device as in Patent Document 3, the applicable work diameter is limited due to the elastic deformation amount limit of the annular elastic body.

  In the three-claw gripping device, the cross-sectional shape of the inner peripheral surface of the workpiece is close to a triangle, and it is difficult to grip the workpiece in a circular shape with high roundness. Furthermore, the suction-type gripping device can grip while maintaining the shape of the workpiece itself, so it can obtain good roundness. However, since the gripping target is cylindrical, only a small suction pad can be used. Sufficient gripping force cannot be generated.

  In view of such circumstances, the present invention provides a gripping device that can grip a workpiece having a wide diameter and can grip the cross-sectional shape of the inner peripheral surface in a circular state with high roundness. It is an issue.

  In order to solve the above-described problems, the present invention provides a gripping device for gripping a workpiece, which has a sheet member wound around the surface of the rotating body or unwound from the surface of the rotating body. The sheet member has flexibility, the sheet member has a cylindrical gripping portion, and the sheet member is unwound from or wound up by the rotation of the rotating body. Thus, the gripping device grips the workpiece by enlarging or reducing the diameter of the gripping portion and the gripping portion abutting against the inner or outer peripheral surface of the workpiece.

  According to the gripping device of the present invention, the sheet member can be wound or unwound while rotating the rotating body while keeping the sheet member along the surface of the workpiece, so that a workpiece having a wide diameter can be gripped. And since the surface of a workpiece | work can be hold | gripped with uniform force along the circumferential direction, the cross-sectional shape of the internal peripheral surface can be hold | gripped in a circular state with high roundness.

It is a figure explaining the holding | gripping apparatus which concerns on 1st embodiment, (a) A figure is a side view, (b) A figure is sectional drawing. It is a figure explaining signs that a grasping device concerning a first embodiment grasps a work. It is a figure explaining signs that a grasping device concerning a first embodiment grasps a work. It is a figure explaining signs that a grasping device concerning a first embodiment grasps a work. It is sectional drawing explaining the layer formation of a sheet | seat member. It is a figure explaining the holding | grip apparatus which concerns on 2nd embodiment, (a) A figure is a side view, (b) A figure is sectional drawing. It is a figure explaining signs that a grasping device concerning a second embodiment grasps a work. It is a figure explaining signs that a grasping device concerning a second embodiment grasps a work. It is a top view which shows the structure of the conventional holding | gripping apparatus. It is a top view which shows the structure of the conventional holding | gripping apparatus. It is a figure explaining the holding | grip apparatus which concerns on 3rd embodiment, (a) A figure is a side view, (b) A figure is a top view. It is a perspective view explaining the structure of a belt member. It is sectional drawing explaining the shape of a cross hole. It is a figure explaining signs that a grasping device concerning a third embodiment grasps a work. It is a side view of the holding | grip apparatus which concerns on 4th embodiment. It is a perspective view of the holding part of the holding apparatus which concerns on 4th embodiment. It is a figure explaining the holding | gripping apparatus which concerns on 5th embodiment, (a) A figure is a side view, (b) A figure is a top view. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a figure explaining a series of flows which hold | grip and convey a workpiece | work. It is a schematic block diagram which shows the structure of the conventional holding | gripping apparatus. It is a schematic block diagram which shows the structure of the conventional holding | gripping apparatus.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

  Fig.1 (a) is a side view which shows the holding | grip apparatus 1 which concerns on 1st embodiment of this invention, FIG.1 (b) is B1-B1 sectional drawing of Fig.1 (a).

  As shown in FIG. 1A, the gripping device 1 of this embodiment includes a rotating body 21, a rotating means 22 such as a motor that rotates the rotating body 21, a fixed shaft 23, and a sheet member 24.

  The fixed shaft 23 is provided only halfway in the axial direction of the rotating body 21, and only the rotating body 21 and the sheet member 24 are provided in the lower part of the figure.

  As shown in FIG. 1B, the rotating body 21 is provided so as to be rotated clockwise or counterclockwise (in the direction of the arrow C1) by the rotating means 22.

  The sheet member 24 has one end fixed to the fixed shaft 23 and the other end fixed to the rotating body 21. The sheet member 24 has flexibility and is held in a state where the sheet member 24 is wound around the surface of the rotary body 21 having a circular cross section.

  When holding a work to be described later, the sheet member 24 is unwound in the direction of the arrow C2 by rotating the rotating body 21 in the direction of the arrow C1. Further, the sheet member 24 can be taken up again by rotating the rotating body 21 in a direction opposite to the arrow C1 (clockwise direction).

  Next, how the gripping device 1 of the present embodiment grips the cylindrical workpiece W will be described with reference to FIGS. 2 and 3. The workpiece W gripped by the gripping device 1 is a cylindrical flexible object having a certain flexibility, and when a pressure is applied from the gripping device 1, the shape of its cross section can be deformed to some extent.

  Examples of the workpiece W include a fixing belt and a fixing sleeve used in a fixing device inside the image forming apparatus. These fixing members have various inner diameters depending on the performance required for the image forming apparatus, and the gripping device 1 is required to support a wide range of workpiece W diameters.

The manner in which the gripping device 1 grips the workpiece W will be described.
First, as shown in FIG. 1B, the rotating body 21 is rotated in the clockwise direction opposite to the arrow C <b> 1 so that the sheet member 24 is wound around the surface of the rotating body 21. Then, as shown in FIG. 2, the workpiece W is inserted into the gripping device 1 from the lower side of the drawing so that the sheet member 24 is arranged inside the workpiece W. At this time, the workpiece W is inserted to a position at the lower end thereof so as not to overlap the fixed shaft 23 in the axial direction of the rotating body 21 and is inserted in a state overlapping with a part of the rotating body 21.

  In this state, the rotating body 21 is rotated in the direction of the arrow C1 shown in FIG. 1B, and the sheet member 24 is unwound.

  At this time, the sheet member 24 is expanded in the direction of the arrow C <b> 2 by the force of returning to the linear shape due to its flexibility, and is unwound along the inner peripheral surface of the workpiece W.

  When all the sheet members 24 are unwound from the rotating body 21, as shown in FIG. 3B, the sheet members 24 are held in a cylindrical state in which a plurality of sheet members 24 are wound on the inner peripheral surface side of the workpiece W. The At this time, the sheet member 24 is subjected to a force to spread outward due to its own flexibility, so that the plurality of wound cylindrical portions (gripping portions) apply contact pressure to the inner peripheral surface of the workpiece W. In addition, the workpiece W can be gripped from the inner peripheral surface side.

  FIG. 4 is a diagram illustrating a state in which the gripping device 1 grips a workpiece W having a larger diameter. As shown in FIG. 4B, even when a workpiece W having a large diameter is used, the sheet member 24 is unwound along the inner peripheral surface of the workpiece W due to the force of spreading outward. As a result, the sheet member 24 comes into contact with the inner peripheral surface of the workpiece W, and the workpiece W can be gripped from the inner peripheral surface side.

  As described above, in the present embodiment, the sheet member 24 is unwound along the diameter of the inner peripheral surface of the workpiece W, so that the workpiece W of the sheet member 24 is gripped in accordance with the diameter of the workpiece W. The diameter of the part is enlarged, and the workpiece W can be gripped from the inner peripheral surface side.

  Further, since the rotating rotor 21 has a circular cross section, the sheet member 24 immediately after being unwound from the outer peripheral surface of the rotating body 21 (unrolled) has a circular tangential direction that is a cross section of the rotating body 21. The force which spreads stably toward (the direction of arrow C2) works. Accordingly, the sheet member 24 can spread in a circular shape having a high roundness while being along the inner peripheral surface of the workpiece W. Therefore, the work W gripped by the sheet member 24 has a high roundness. It will be gripped from the inner peripheral surface side in a circular shape.

  Further, by providing the sheet member 24 with a sufficient length with respect to the inner peripheral surface of the workpiece W, as described above, the sheet member 24 comes into contact with the inner peripheral surface of the workpiece W to be gripped in a state where a plurality of windings are made. .

  In the method of unwinding the sheet member 24 and bringing it into contact with the inner peripheral surface of the workpiece W as in the present embodiment, in the circumferential direction of the rotating body 21 (hereinafter also simply referred to as the circumferential direction) shown in FIG. In the range G from the position of the fixed shaft 23 where one end of the sheet member 24 is fixed to the fixed position of the rotating body 21 where the other end is fixed, the sheet member 24 overlaps the workpiece W by one turn and the workpiece Abuts against the inner circumferential surface of W. Due to the difference in the number of sheet members 24 that are wound, the gripping force of the workpiece W becomes non-uniform in the range G and other portions in the circumferential direction.

  However, in this embodiment, as described above, the sheet member 24 is wound many times and comes into contact with the work W, so that the difference in overlap of one turn is relatively small, and the gripping force of the work W is increased. The direction can be made as uniform as possible. For this reason, the roundness of the workpiece W can be further improved.

  Further, an elastic layer can be provided on the rotating member 21 side of the sheet member 24. By providing the elastic layer, when the sheet member 24 comes into contact with the inner peripheral surface of the workpiece W and overlaps many times, the elastic layer is crushed, and the difference in overlap of the one turn is relatively Can be small. For this reason, the gripping force of the workpiece W can be made as uniform as possible in the circumferential direction, and the roundness of the workpiece W can be further improved.

  Further, as shown in FIG. 5, a sliding layer 24 a excellent in slidability may be provided on the surface of the sheet member 24 on the rotating body 21 side. Thereby, when the sheet member 24 is unwound, the sliding resistance between the sheet members 24 or between the sheet member 24 and the rotating body 21 is reduced, and the sheet member 24 is smoothly unwound. For this reason, the roundness of the workpiece | work W improves more and the torque required in order to rotate the rotary body 21 reduces.

  In addition to the configuration in which the rotational torque of the rotating means 22 is constant when the sheet member 24 is unwound, the rotational torque may be controlled according to the unwinding amount of the sheet member 24. As a result, the gripping force of the workpiece W is reduced due to insufficient force for feeding (unwinding) the sheet member 24, and conversely, an excessive load is applied to the sheet member 24 and the workpiece W due to the excessively large feeding force. It is possible to prevent the roundness of the workpiece W from being lowered. Further, even after the sheet member 24 is sent out following the inner peripheral surface of the workpiece W, the force to be fed to the sheet member 24 can be applied, so that the gripping force of the workpiece W can be improved.

  Next, an experimental result in the case where the workpiece is held by each of the gripping device of the present embodiment and the gripping devices of other types will be described.

  The workpiece to be gripped is a SUS cylindrical sleeve having a thickness of 50 μm and inner diameters of φ25, 30, 40, and 50 mm, respectively.

  The gripping devices to be compared are the balloon method that can support multiple diameters, the balloon method that does not support multiple diameters, the three-claw method, the suction method, and the sheet member external bending method, which are compared in the order listed first. Examples 1 to 5. In the balloon method that does not support multi-diameters, only a workpiece having a diameter of 25 mm is gripped, and in the balloon method that can support multi-diameters, all types of workpieces described above are gripped.

  In the balloon system, chloroprene rubber having an outer diameter of 23 mm and a thickness of 1 mm was used as a cylindrical elastic body, and the diameter was expanded with compressed air of 0.4 MPa to grip the workpiece W.

  In the three-claw method, the workpiece W was gripped with a claw insertion amount of 30 mm and a claw opening force of 18 N.

  In the suction method, the workpiece W was held at a vacuum pressure of −60 kPa using a soft bellows type suction pad made of nitrile rubber with a tip outer diameter of 6 mm, an inner diameter of 2.2 mm.

  In the sheet member outer bending method, the workpiece W was gripped using a plate spring made of SUS304 having a thickness of 0.05 mm and a length of 60 mm as the sheet member.

  Table 1 shows the results of gripping the workpiece W by each method under the above conditions.

  Comparing the results of this embodiment with the results of the comparative example, in this embodiment, the roundness of the gripped work W was 0.25 mm, and the roundness was the highest. Further, the gripping force of the workpiece W was 2N or less in Comparative Examples 4 and 5, whereas in this embodiment, a sufficient gripping force was obtained at 7N or more. As for the result of the durability of the gripping device (the number of times that the gripping device can grip the workpiece with sufficient gripping force), the durability in Comparative Example 1 is 100,000 times or less, and the elastic force of rubber after 100,000 times of gripping. It is considered that a sufficient gripping force could not be obtained due to a decrease in the amount of sag. On the other hand, in this embodiment, even after gripping 500,000 times or more, a sufficient gripping force was obtained and the durability was good.

  As described above, in this embodiment, good results can be obtained in all items, and the gripping device of this embodiment can stably grip a workpiece with a larger gripping force, and the cross-sectional shape of the workpiece It can be seen that can be held in a circle with high roundness.

  Next, a gripping device according to a second embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 6A, in the second embodiment, a ball roller 29 that is movable with respect to the housing 25 is provided in a direction perpendicular to the axial direction of the rotating body 21 (left-right direction in the figure). The ball roller 29 is fixed to the rotating means 22 and the rotating body 21 and can move integrally therewith.
In the ball roller 29, ball portions 291 provided on the upper and lower surfaces of the left and right ends are in contact with the wall surface of the housing 25. When the ball portion 291 rolls on the wall surface of the housing 25, the ball roller 29 can move on a plane perpendicular to the axial direction of the rotating body 21 (on the paper surface of FIG. 6B). Accordingly, the rotating means 22 and the rotating body 21 move horizontally on the surface. The fixed shaft 23 is fixed to the housing 25.

A state where the workpiece W is gripped by the gripping device 1 of the second embodiment will be described.
As shown in FIG. 7A, as in the first embodiment, the workpiece W is held from the lower side of the drawing so that the sheet member 24 is arranged inside the workpiece W to be held by the holding device 1. Insert into. Then, the sheet member 24 is unwound by the rotation of the rotating body 21, and a force to spread outward acts on the sheet member 24, so that the sheet member 24 spreads along the inner peripheral surface of the workpiece W, and the inner peripheral surface The workpiece W can be gripped from the inner peripheral surface side.

  In the present embodiment, the ball roller 29 is in contact with the inner peripheral surface of the work W while the ball roller 29 is in contact with the inner peripheral surface of the work W by the force received by the sheet member 24 from the contact surface with the work W. Move horizontally on a plane perpendicular to. Thereby, the rotating body 21 moves relative to the workpiece W and the sheet member 24, and the rotating body 21 moves to a position where the force applied from the workpiece W to the sheet member 24 becomes more uniform on the surface. Therefore, the gripping force in the circumferential direction of the workpiece W of the sheet member 24 can be made constant, and the roundness of the workpiece W can be further improved. As shown in FIG. 8A, even when the diameter of the workpiece W to be gripped is large, the gripping force of the sheet member 24 can be made uniform in the circumferential direction by the movement of the ball roller 29 in the same manner.

  In the above embodiment, the configuration in which the sheet member 24 grips the inner peripheral surface of the workpiece W by unwinding the sheet member 24 by the rotation of the rotating body 21 has been described. In the following embodiments, on the contrary, the sheet member 24 is disposed outside the outer peripheral surface of the work W, and the outer peripheral surface of the work W is removed by winding the sheet member 24 by the rotation of the rotating body 21. The structure to hold | grip is demonstrated.

  As described above, a fixing sleeve or the like is given as the work W to be gripped. In the fixing sleeve, an elastic layer (about 100 to 300 μm) made of heat-resistant rubber (silicone rubber) is formed on a base material layer made of polyimide, SUS, Ni or the like having a thickness of about 30 to 100 μm. A primer (adhesive) is applied to form a release layer (fluororesin) of about 15 to 30 μm.

  In some cases, a fluororesin-based paint or a carbon-based paint is applied to the inner surface of the fixing sleeve to impart lubricity or conductivity. And, when the shape of the fixing sleeve is changed immediately after the inner surface coating, the paint moves to a portion with a small radius of curvature, so that the uniformity of the coating film thickness cannot be maintained, but the fixing sleeve is thin, There is a problem of low rigidity and easy deformation. In addition, since it is immediately after the inner surface coating, it cannot be brought into contact with the inner surface of the workpiece W, and a gripping device for gripping the workpiece W from the outer peripheral surface side is required. Furthermore, in order to improve work efficiency when workpieces are automated, it is necessary to omit setup work even with multiple models using fixing sleeves with different diameters, and a gripping device 1 that can handle workpieces W of a wide range of diameters is required. It is done.

  As a gripping device for gripping a cylindrical workpiece from the outer peripheral surface side, a configuration using a suction pad or an electric or pneumatic chuck can be considered. For example, in the well-known configuration employing the electric chuck shown in FIG. 9, the electric chuck 50 is provided with a pair of V-shaped grippers 51. The V-shaped gripper 51 is operated by the electric chuck 50 and grips the workpiece W by applying a force for sandwiching the workpiece W.

  As shown in FIG. 10, there is a known technique in which a clamping tool 61 is attached to an electric chuck 60. The belt member 62 having one end fixed to the first gripper 63 is wound around the outer peripheral surface of the workpiece W, the other end of the belt member 62 is fixed to the second gripper 64, the gripper is operated by the electric chuck 60, and the workpiece W is Grab.

  However, in the gripping device having the above-described configuration, a large pressure is applied to the workpiece W, and a workpiece having high rigidity is mainly gripped. For this reason, it is unsuitable for a work having a small rigidity such as the above-described fixing sleeve, and it is difficult to form a cross section of the work in a circular shape having a high roundness.

  As a configuration for solving the above problems, the configuration of each embodiment for gripping the outer peripheral surface of the workpiece W with the gripping device of the present invention will be described below.

  As shown in FIG. 11A, the gripping device according to the third embodiment of the present invention includes a rotating body 21, a rotating unit 22 such as a motor that rotates the rotating body 21, and a belt member 31 as a sheet member. Have. The cylindrical workpiece W is disposed on the inner side of the belt member 31 so as to cover the entire circumference thereof, and is gripped by the belt member 31.

  Since the belt member 31 needs to have both thinness and strength, it is desirable to use steel or stainless steel having a thickness of 0.01 mm to 0.5 mm.

  As shown in the top view of FIG. 11B, one end 311 of the belt member 31 is fixed to the casing 30 of the gripping device 1, and the other end 312 is fixed to the surface of the rotating body 21. The belt member 31 includes a grip portion 313 that is a portion where the belt 310 abuts on the outer peripheral surface of the workpiece W and grips the workpiece W, and a winding portion 314 that is a portion where the belt 310 is wound around the rotating body 21. Have.

  As shown in FIG. 12, one end 311 of the belt member 31 has an intersecting hole 315, and the other end 312 of the belt member 31 is inserted into the intersecting hole 315. The grip portion 313 is formed.

  As shown in FIG. 13, the cross hole 315 is inserted into the end surface of the cross hole 315 on the winding part 314 side from the insertion port of the belt 310 of the cross hole 315 toward the exit direction (arrow direction in the figure). The inclined surface E is provided in the direction in which the width increases. Thereby, the level | step difference in the location of the cross hole 315 can be made small, and the roundness of the workpiece | work W which the belt member 31 hold | grips can be improved more by reducing the frictional resistance of the belts 310 in this part. I can do things.

  As shown in FIG. 11B, the belt member 31 has an annular gripping portion 313 with one end 311 as an end portion, and the other end side extends through the cross hole 315 to the rotating body 21 side. The winding part 314 is formed. The other end is extended in a tangential direction of a cylindrical gripping portion 313 (circular in cross section) and wound around the outer periphery of the rotating body 21 to form a winding portion 314.

  By rotating the rotating body 21 in the direction of the arrow D1, the belt 310 is wound from the position of the cross hole 315 in the direction of the arrow D2 (tangential direction of the gripping portion 313), and then on the outer peripheral surface of the rotating body 21. Along the direction of arrow D1. Thereby, the gripping part 313 grips the workpiece W while applying pressure in the direction of the arrow D5 that is the center direction of the workpiece W to the outer peripheral surface of the workpiece W.

  In the present embodiment, the workpieces having different diameters can be gripped by adjusting the lengths of the belts 310 disposed on the gripping portion 313 and the winding portion 314 by the rotation of the rotating body 21.

  For example, as shown in FIG. 14, when gripping a workpiece W having a large diameter, the belt of the winding unit 314 is almost unwound toward the gripping unit 313. In the present embodiment, a workpiece W having an outer peripheral diameter of Φ20 to Φ150 mm can be gripped.

  In the above embodiment, one belt member 31 is arranged. However, in the gripping device of the fourth embodiment shown in FIG. 15, a plurality of belt members 31 are provided in the axial direction of the rotating body 21. In this case, as shown in FIG. 16, a plurality of intersecting holes 315 are provided at one end 311, and the belt 310 is inserted into each of them to intersect the belt 310 at this position. By gripping the workpiece W by the plurality of belt members 31, the positioning accuracy and roundness of the workpiece W can be improved. Further, by making it possible to individually change the winding amount and gripping force of the belt 310 of each belt member 31, the length and gripping force of the belt 310 are smaller than when only one belt member 31 is provided. Adjustment is possible.

  As in the present embodiment, in the configuration in which the work W is gripped by pressing the outer peripheral surface of the work W, it is difficult to sufficiently secure the gripping force of the work W by the belt member 31 when the diameter of the work W is small. End up. On the other hand, by increasing the friction coefficient of the inner peripheral surface of the belt member 31, the frictional force generated between the belt member 31 and the workpiece W can be increased and the gripping force of the workpiece W can be increased.

  However, if the frictional force is excessively increased, there is a problem that the roundness of the workpiece W to be gripped is lowered depending on the diameter of the workpiece W to be gripped and the friction coefficient of the surface. Therefore, it is desirable to set the friction coefficient between the belt member 31 and the workpiece W to 0.2 to 0.5.

  In particular, when a plurality of belt members 31 are arranged as described above, by setting the respective friction coefficients to different values, a more appropriate belt can be obtained according to the diameter of the workpiece W to be gripped and the friction coefficient of the surface. The member 31 can be selected and gripped.

  Furthermore, as a configuration for improving the gripping force of the workpiece W, the configuration of the gripping device of the fifth embodiment will be described with reference to FIG.

  As shown in FIG. 17A, the gripping device 1 of the fifth embodiment is provided with a holding member 32 that holds the outer peripheral surface of the workpiece W separately from the belt member 31 above the belt member 31.

  As shown in the top view of FIG. 17B, the holding member 32 has an L-shaped first holding portion 321 that holds the workpiece W in contact with the outer peripheral surface of the workpiece W, and a linear second member. A holding portion 322 is included. The first holding part 321 is provided so as to be movable in the vertical and horizontal directions in the figure, and the second holding part 322 is movable in the vertical direction in the figure. The first holding part 321 and the second holding part 322 can be brought into contact with the outer peripheral surface of the work W by moving them according to the diameter of the work W, respectively. The force applied to the work W by the first holding part 321 and the second holding part 322 by the contact is set to be sufficiently small so as not to affect the shape of the work W.

  When the first holding part 321 and the second holding part 322 hold the workpiece W from the outer peripheral surface side, the gripping force and positioning accuracy of the workpiece W of the gripping device 1 are further improved.

  Next, a series of flows in which the gripping device 1 grips the workpiece W at a predetermined position and conveys it to a target position will be described. In addition, it demonstrates using the holding | grip apparatus 1 which concerns on 5th embodiment shown in FIG.

  As shown in FIG. 18, the gripping device 1 is attached to the tip of a hook 34 provided in a transport mechanism 33 such as a robot arm or a robot cylinder. The gripping device 1 performs an operation of gripping the workpiece W and transporting it from the initial position F1 to the target position F2.

  First, as shown in FIG. 18, the gripping portion 313 of the gripping device 1 is carried over the workpiece W. Then, as shown in FIG. 19, the rotating body 21 is rotated in the direction of the arrow D3, and the belt 310 is unwound from the winding unit 314 to the gripping unit 313 (in the direction of the arrow D4). Thereby, the diameter of the grip part 313 is made larger than the workpiece W.

  And as shown in FIG. 20, the holding part 313 is arrange | positioned on the outer periphery of the workpiece | work W by moving the hook 34 below.

  In this state, as shown in FIG. 21, by rotating the rotating body 21 in the direction of the arrow D1, the belt 310 is wound around the take-up portion 314 to reduce the diameter of the grip portion 313. The part 313 is brought into contact with the outer peripheral surface of the workpiece W. As a result, the gripping portion 313 contacts the outer peripheral surface of the workpiece W while applying pressure in the direction of the arrow D5 and grips the workpiece W.

  After the workpiece W is gripped by the gripping device 1, as shown in FIG. 22, the workpiece W (the gripping device 1) is lifted upward by the hook 34, and the workpiece W is translated in the right direction in the drawing by the transport mechanism 33. Then, the workpiece W is conveyed to above the target position F2.

  And as shown in FIG. 23, the 1st holding | maintenance part 321 and the 2nd holding | maintenance part 322 are respectively moved to the direction of the arrow of a figure by moving the 1st holding | maintenance part 321 and the 2nd holding | maintenance part 322, and the outer peripheral surface of the workpiece | work W. To hold the workpiece W. By holding the workpiece W by the holding member 32, the workpiece W can be positioned more accurately. In addition, by synchronizing the position information of the first holding unit 321 and the second holding unit 322 and the position information of the target position F2, the workpiece W can be more reliably transported to a predetermined position.

  After the workpiece W is held by the holding member 32, the workpiece W can be placed at the target position F2 by moving the hook 34 downward as shown in FIG.

  Finally, as shown in FIG. 25, the workpiece W is released from the gripping device 1 by releasing the gripping of the workpiece W by the gripping device 1 and the holding of the workpiece W by the holding member 32. Specifically, the rotating body 21 is rotated in the direction of the arrow D3, the belt 310 is unwound in the direction of the arrow D4, and the workpiece W is released from the grip portion 313. Further, the workpiece W is released from the holding member 32 by moving the first holding portion 321 in the upper left direction in the drawing and the second holding portion 322 in the lower direction in the drawing.

  Then, the gripping device 1 is transported by the transport mechanism 33 and moved to the initial position F1, and can shift to a posture for gripping the next workpiece W.

  Next, experimental results when gripping a workpiece with respect to each of the gripping devices of the third to fifth embodiments and other types of gripping devices will be described.

  The belt member 31 of the gripping device of Example 1 (corresponding to the gripping device of the third embodiment) is SUS304 having a thickness of 0.1 mm, a width of 10 mm, and a surface roughness Ra of 6.3 μm or less. Moreover, the angle of the inclined surface E in the cross hole 315 was set to 45 degrees. The rotating means 22 uses a servo motor to perform torque control. The tension of the belt member 31 is set to be 5N.

  The gripping device of Example 2 (corresponding to the gripping device of the fourth embodiment) uses three belt members 31 and is arranged in the axial direction at intervals of 20 mm. Other settings are the same as in the first embodiment.

  The gripping device of Example 3 is the same as the gripping device of Example 2, but the length and tension of each belt member 31 can be individually controlled.

  In the gripping device of Example 4 (corresponding to the gripping device of the fifth embodiment), a holding member 32 is added to the configuration of Example 3. The material of the holding member 32 is SUS304, and the surface thereof is set to Ra 0.8 μm or less. In a state where the holding member 32 holds the workpiece W, the first holding portion 321 and the second holding portion 322 are arranged at positions that are ± 0.2 mm with respect to the set value of the outer peripheral diameter of the workpiece W.

  Comparative Example 1 uses the configuration of the known gripping device shown in FIG. 9, and Comparative Example 2 uses the configuration of the known gripping device shown in FIG.

The work W uses two kinds of work WA and work WB.
The workpiece WA has an outer diameter Φ25, a wall thickness of 40 μm, a length of 320 mm, and a fixing sleeve made of a material SUS304 and a fluororesin-based paint applied to the inside by 15 μm. The workpiece WB has an outer diameter of Φ50, a thickness of 40 μm, a length of 320 mm, and a SUS304 fixing sleeve made of a material SUS304 with a fluororesin-based paint applied to the inside by 15 μm. The workpiece WA and the workpiece WB are both used after being coated on the inner surface and before drying.

  The transport mechanism 33 transports the gripping device at a speed of 300 mm / sec using an orthogonal ROBO cylinder (manufactured by IAI).

  In this experiment, in a state where the workpiece W is gripped by each gripping device, the workpiece W is transported to the target position F2 that is 500 mm away from the initial position F1, and the center position and roundness of the workpiece W at the target position F2 are measured. The measurement is performed 20 times, and the average value of the variation 3σ of the center position of the workpiece W and the roundness of the workpiece W is obtained. The measurement was performed with a measuring device CV-X200 (manufactured by Keyence Corporation).

  Each criterion is determined to be good (◯) if the variation 3σ of the center position of the workpiece W is 10 mm or less, and defective (×) if it is larger than 10 mm, and good if the average roundness is 0.4 mm or less. It judged with ((circle)), and if it was larger than 0.4 mm, it determined with it being a defect (x).

  Moreover, after the work W dried the inner surface, the external appearance inspection was performed visually and it was evaluated whether there was any coating film nonuniformity. When there was no coating unevenness, it was judged as good (◯), and when the coating unevenness was observed visually, it was judged as defective (×).

  Table 2 shows the results of the experiment conducted under the above conditions.

比較例１と２では、ワークＷＡ、ワークＷＢともに、ワークの中心位置ばらつき、真円度平均値、内面外観塗装が全て×で、好ましくない結果となった。これに対して、実施例１から４では、ワークＷＡ、ワークＷＢともに、全ての項目で○になり、好ましい結果となった。本発明の各実施形態の構成を用いる事により、ワークＷを把持して目標位置に正確に搬送する事ができる事がわかる。また、ワークＷの真円度が良好であることから、ワークＷの外周面に対して均一に力を加える事ができるので、塗装ムラが出にくく、上記の結果となった。

In Comparative Examples 1 and 2, for both the workpiece WA and the workpiece WB, the variation in the center position of the workpiece, the roundness average value, and the inner surface appearance coating were all x, which was not preferable. On the other hand, in Examples 1 to 4, both the work WA and the work WB were “good” in all items, and favorable results were obtained. It can be seen that by using the configuration of each embodiment of the present invention, the workpiece W can be gripped and accurately conveyed to the target position. Further, since the roundness of the workpiece W is good, it is possible to apply a force uniformly to the outer peripheral surface of the workpiece W, so that the coating unevenness hardly occurs and the above result is obtained.

  Moreover, when the results of Examples 1 to 4 were compared, better results were obtained for the later examples in each item. Since the result of Example 2 is better than the result of Example 1, it is understood that the gripping force and the gripping posture with respect to the work W are more stable by gripping the work W by the plurality of belt members 31. In addition, since the result of Example 3 is better than the result of Example 2, it is possible to adjust the length and tension of each belt member 31 individually, so that the workpiece W can be adjusted with a more appropriate gripping force. It can be seen that the roundness of the workpiece W is improved. Furthermore, since the result of Example 4 is better than the result of Example 3, by holding the workpiece W from the outside of the belt member 31 by the holding member 32, the posture of gripping the workpiece W is particularly stable. It turns out that each result became favorable.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  In the description of the present embodiment, the workpiece W gripped by the gripping device 1 has been described as a fixing member such as a fixing sleeve. However, it is a matter of course that the present invention can also be applied to a member having a circular cross section such as a photosensitive belt.

DESCRIPTION OF SYMBOLS 1 Gripping device 21 Rotating body 22 Rotating means 24 Sheet member 24a Sliding layer 31 Belt member (sheet member)
311 One end 312 The other end 313 Grip portion 315 Cross hole 32 Holding member E Inclined surface W Workpiece

Japanese Patent No. 5512248 Japanese Patent Application Laid-Open No. 07-163934 Japanese Patent No. 2800448

Claims (10)

A rotating body,
A gripping device for gripping a workpiece, having a sheet member wound around the surface of the rotating body by rotation of the rotating body or unwound from the surface of the rotating body,
The sheet member has flexibility,
The sheet member has a cylindrical gripping portion, and the sheet member is unwound from or wound up by the rotation of the rotating body, thereby increasing or decreasing the diameter of the gripping portion, A gripping device that grips a workpiece by a gripping portion coming into contact with an inner circumferential surface or an outer circumferential surface of the workpiece.   The gripping apparatus according to claim 1, wherein the sheet member is unwound by rotation of the rotating body to increase a diameter of the gripping portion, and the gripping portion contacts an inner peripheral surface of the workpiece.   The gripping device according to claim 2, wherein the sheet member grips the workpiece in a state where a plurality of the sheet members overlap each other. Rotating means for rotating the rotating body,
The gripping device according to claim 2 or 3, wherein a rotational torque for rotating the rotating body by the rotating means is provided to be controllable.   The gripping device according to any one of claims 2 to 4, wherein the rotating body is provided so as to be relatively movable with respect to the workpiece and the belt member on a plane perpendicular to the axial direction thereof. The gripping part is wound around the rotating body by the rotation of the rotating body, so that the diameter of the gripping part is reduced and the gripping part comes into contact with the outer peripheral surface of the workpiece,
The gripping device according to claim 1, wherein a direction in which the gripping part is wound is a circular tangential direction of a cylindrical cross section of the gripping part. The sheet member is in contact with the outer peripheral surface of the work and has an annular gripping part for gripping the work.
The grip portion is configured by inserting the other end side of the sheet member into a cross hole which is a hole provided at one end of the sheet member,
The gripping device according to claim 6, wherein the cross hole has an inclined surface in a direction in which an insertion width of the cross hole widens from an insertion port on the other end side of the sheet member toward an exit direction thereof.   The gripping device according to claim 6, wherein a plurality of workpieces gripped by the sheet member are provided in the axial direction.   The plurality of sheet members are wound around the surface by a plurality of different rotating bodies, or are unwound from the surface of the plurality of rotating bodies, and the amount of winding of the sheet member of each rotating body is reduced. The gripping device according to claim 8, which can be individually changed.   The gripping device according to any one of claims 6 to 9, further comprising a holding member that abuts on an outer peripheral surface of the work and holds the work separately from the belt member.

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