JP2021091032A - Holding device and control method of the same - Google Patents

Abstract

To provide a holding device which can hold a workpiece with pads having fluidity even if there is not enough space available at both sides of the workpiece.SOLUTION: A holding device 5 holds a workpiece and includes: a left arm unit 5L and a right arm unit 5R; a gripper body 6 which opens or closes these arm units 5L, 5R along a holding direction; pads 59, 59 having fluidity and provided at the arm units 5L, 5R; a vacuum pump which changes hardness of the pads 59, 59; and a roller unit 8 which causes the rollers 82, 82 to roll along surfaces of the pads 59, 59 to level the surfaces of the pads 59, 59. The roller unit 8 causes the rollers 82, 82 to roll along the surfaces of the pads 59, 59 so that surfaces of the rollers 82, 82 sequentially contact with the surfaces of the pads 59, 59 along a vertical direction from the lower end side to the upper end side.SELECTED DRAWING: Figure 9

Description

The present invention relates to a gripping device and a control method thereof. More specifically, the present invention relates to a gripping device for gripping a work by a pad having fluidity and a control method thereof.

For example, in an automobile production line, a gripping device for gripping a work is provided on a robot arm of a transfer robot that conveys the work. The gripping device grips the work by closing at least two arm members by a chuck mechanism and sandwiching the work with pads provided on these arm members.

In such a gripping device, it is necessary to make the shape of the pad follow the shape of the work in order to prevent the work from falling off or being damaged. In recent years, those using a pad having fluidity have been proposed so that workpieces having various shapes can be gripped. For example, in the gripping device shown in Patent Documents 1 and 2, a bag-shaped member filled with granules is used as a pad.

Japanese Unexamined Patent Publication No. 2006-7337 Japanese Unexamined Patent Publication No. 2014-8583

By the way, in the gripping device using the pad having the above-mentioned fluidity, it is necessary to use the pad having a certain thickness in order to be able to deform according to the uneven shape of various workpieces. However, when the pad becomes thick, if there is not enough space on both sides of the work, the pad cannot be inserted on both sides of the work, and it becomes difficult to grip the work.

An object of the present invention is to provide a gripping device and a control method thereof capable of gripping a work by a pad having fluidity even when there is not enough space on both sides of the work.

(1) The gripping device (for example, the gripping device 5 described later) according to the present invention grips a work (for example, the work W described later) and has a plurality of arm portions (for example, the left arm unit 5L described later). And the arm portion 51) of the right arm unit 5R, a main body that opens and closes the plurality of arm portions along the gripping direction (for example, the gripper main body 6 described later), and among the plurality of arm portions that are fluid and have fluidity. A pad provided in at least one (for example, a pad 59 described later), a curing means for changing the hardness of the pad (for example, a vacuum pump 4 and a control device 9 described later), and a roller (for example, a roller described later). 82, 82A) is provided with leveling means (for example, roller units 8 and 8A described later, a transfer robot 3 and a control device 9) for leveling the surface of the pad by rolling it along the surface of the pad. It is characterized by.

(2) In this case, the roller is rotatable about an axis substantially perpendicular to the gripping direction, and the leveling means is the pad and the pad in a state where the pad is pressed against the surface of the roller. It is preferable to change the position of the arm portion along the gripping direction while moving both or either of the rollers along the gripping direction and the sliding direction substantially perpendicular to the axis.

(3) In this case, the leveling means brings the roller onto the surface of the pad so that the surface of the roller abuts on the surface of the pad in order from the lower end side to the upper end side along the vertical direction. It is preferable to roll along.

(4) In this case, when the curing means smoothes the surface of the pad by the leveling means, the hardness of the pad is changed from the case where the shape of the pad is changed according to the shape of the work. It is also preferable that the pad is hard and softer than when the work is gripped by the pad.

(5) The gripping device (for example, the gripping device 5 described later) holds the plurality of arm portions (for example, the arm portions 51 of the left arm unit 5L and the right arm unit 5R described later) and the plurality of arm portions in the gripping direction. A main body that opens and closes along the line (for example, a gripper main body 6 described later), a pad that has fluidity and is provided on at least one of the plurality of arm portions (for example, a pad 59 described later), and the pad. A curing means (for example, a vacuum pump 4 and a control device 9 described later) for changing the hardness is provided, and the work is gripped by pressing the pad against a work (for example, a work W described later). The control method of the gripping method according to the present invention is a leveling step of leveling the surface of the pad by rolling a roller (for example, rollers 82, 82A described later) along the surface of the pad (for example, FIG. 8 described later). Step S7) and a gripping step of gripping the work with the pad by bringing the pad whose surface is leveled by the roller close to the work (for example, steps S1 to S4 of FIG. 8 described later). It is characterized by having.

(6) In this case, the gripping step is a deformation step of changing the shape of the pad according to the shape of the work by pressing the pad against the work while vibrating the pad (for example, in S3 of FIG. 8 described later). Step) and a curing step (for example, S4 of FIG. 8 described later) in which the pad is cured in a state where the shape of the pad is changed according to the shape of the work, and the work is gripped by the cured pad. In the leveling step, it is preferable that the pad is made harder than the deformation step and softer than the hardening step by using the curing means.

(1) The gripping device according to the present invention has a plurality of arm portions, a main body that opens and closes the plurality of arm portions along the gripping direction, and at least one of the plurality of arm portions having fluidity. The pad is provided, a curing means for changing the hardness of the pad, and a leveling means for leveling the surface of the pad by rolling a roller along the surface of the pad. According to the present invention, the pad can be made thin by leveling the surface of the pad using a leveling means. Therefore, even if there is not enough space on the side of the work, the pad is inserted and the work is made by this pad. Can be grasped. Further, according to the present invention, the contact area between the pad and the work can be increased by leveling the surface of the pad by using a leveling means before deforming the pad according to the shape of the work. The gripping force of the pad can be increased.

(2) In the present invention, the leveling means moves the pad and / or the roller along the gripping direction and the sliding direction substantially perpendicular to the axis of the roller while the pad is pressed against the surface of the roller. While doing so, the position of the arm portion along the gripping direction is changed. Thereby, the thickness of the pad along the gripping direction can be changed along the sliding direction. Further, this makes it possible to set the profile shape along the sliding direction of the thickness of the pad so that the work can be gripped in an appropriate manner according to the characteristics of the work, the shape of the space on the side of the work, and the like.

(3) The pad tends to sag on the lower end side in the vertical direction due to its own weight. On the other hand, in the present invention, the leveling means rolls the roller along the surface of the pad so that the surface of the roller contacts the surface of the pad in order from the lower end side to the upper end side along the vertical direction. As a result, the surface of the pad can be leveled by gathering the slack portions on the lower end side.

(4) In the present invention, when the surface of the pad is leveled by the leveling means, the hardness of the pad is harder than when the shape of the pad is changed according to the shape of the work, and the pad is used. Make it softer than when gripping the work. As a result, the surface of the pad can be appropriately leveled by the leveling means, and the shape after leveling can be maintained. Further, by changing the hardness of the pad as described above, when the shape of the pad is changed, it can be changed so as to follow the uneven shape of the work, and when the work is gripped, it is firmly gripped. Can be done.

(5) The control method of the gripping device according to the present invention is to smooth the surface of the pad by rolling a roller along the surface of the pad having fluidity, and then bring the smoothed pad closer to the work. Hold the work with the pad. According to the present invention, since the surface of the pad can be leveled and the pad can be made thin, the pad can be inserted and the work can be gripped by the pad even when there is not enough space on the side of the work. Further, according to the present invention, by leveling the surface of the pad before gripping the work with the pad, the contact area between the pad and the work can be increased, so that the gripping force of the pad can be increased. ..

(6) In the present invention, after the surface of the pad is leveled (leveling step), the shape of the pad is changed according to the shape of the work by pressing the pad against the work while vibrating (deformation step). The pad is cured in a state where the shape of the pad is changed according to the shape of the work (curing process). Further, in the present invention, the hardness of the pad in the leveling step is made harder than that in the deformation step and softer than that in the hardening step. As a result, in the leveling step, the surface of the pad can be appropriately leveled and the shape after leveling can be maintained. Further, by changing the hardness of the pad as described above, the pad can be deformed so as to follow the uneven shape of the work in the deformation step, and the work can be firmly gripped in the hardening step.

It is a figure which shows the structure of the work transfer system to which the gripping apparatus which concerns on one Embodiment of this invention is applied. It is a front view of the gripping device. It is a side view which looked at the right arm unit in the direction perpendicular to the gripping direction. It is a rear view which shows the structure of the outside of a right arm unit. It is a perspective view which looked at the right arm unit from the outside. It is a perspective view which shows the structure of the piping unit and the stopper support arm among the right arm units. It is sectional drawing along the line VII-VII in FIG. 4 of a base and a piping unit. It is a figure which shows typically the procedure of carrying a work. It is a figure which shows the procedure of leveling the surface of a pad by a roller unit. It is a figure which shows the tip-type pad. It is a figure which shows the tapered type pad. It is a figure which looked at the connecting member of the modification 1 along the direction perpendicular to the gripping direction. It is a figure which looked at the connecting member of the modification 2 along the direction perpendicular to the gripping direction. It is a figure which looked at the connecting member of the modification 3 along the direction perpendicular to the gripping direction. It is a figure which shows the example of the case where the roller unit is fixed to the gripper main body. It is a figure which shows the example of the case where the surface of a pad is leveled by the roller unit fixed to the gripper body.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a work transfer system S to which the gripping device 5 according to the present embodiment is applied. FIG. 2 is a front view of the gripping device 5.

The work transfer system S includes a carriage 11 on which a plurality of works W are mounted, a transfer robot 3 to which a gripping device 5 for gripping the work W is attached, a roller unit 8 provided in the vicinity of the gripping device 5, and a roller unit 8. A control device 9 for controlling the transfer robot 3 and the gripping device 5 is provided. The work transfer system S is provided, for example, on a vehicle manufacturing line, and one of a plurality of work Ws placed on the carriage 11 is taken out and taken out by a transfer robot 3 and a gripping device 5 under the control of the control device 9. The work W is transported to a predetermined position on the serving table 12.

The gripping device 5 opens and closes the columnar left arm unit 5L and right arm unit 5R that grip the work W by sandwiching the work W, and these arm units 5L and 5R along the gripping direction (left-right direction in FIGS. 1 and 2). The gripper main body 6 is provided. The gripping device 5 is fixed to the tip 32 of the articulated arm 31 of the transfer robot 3 at a mounting portion 61 provided on the side of the gripper main body 6 opposite to the arm units 5L and 5R. Therefore, by driving the transfer robot 3 by the control device 9 and controlling the position and posture of the tip portion 32 of the articulated arm 31, the gripping device 5 and the work W gripped by the gripping device 5 can be moved. As shown in FIG. 1, the transfer robot 3 basically grips and conveys the work W with the arm units 5L and 5R parallel to the vertical direction.

The arm units 5L and 5R are supported by the gripper main body 6 at their respective base ends in a state of being parallel to each other. Further, these arm units 5L and 5R grip the work W by sandwiching them with pads 59 and 59, which will be described later, provided inside the respective tip portions. The gripper main body 6 has a guide rail (not shown) that extends along the gripping direction and slidably supports the base ends of the arm units 5L and 5R, and the arm unit 5L in response to a command from the control device 9. , 5R is provided with an actuator (not shown) for moving along the guide rail. More specifically, the actuator of the gripper body 6 closes the arm units 5L and 5R by bringing the arm units 5L and 5R close to each other along the guide rail, and separates the arm units 5L and 5R from each other along the guide rail. By letting it open, the arm units 5L and 5R are opened.

Next, the configurations of the arm units 5L and 5R will be described with reference to FIGS. 3 to 7. The left arm unit 5L and the right arm unit 5R basically have the same configuration. Therefore, in the following, the configuration of the right arm unit 5R will be mainly described in detail, and the detailed description of the configuration of the left arm unit 5L will be omitted.

FIG. 3 is a side view of the right arm unit 5R viewed along a direction perpendicular to the gripping direction, FIG. 4 is a rear view showing the outer configuration of the right arm unit 5R, and FIG. 5 is a right view. It is a perspective view which looked at the arm unit 5R from the outside.

The right arm unit 5R includes an arm portion 51 extending in the vertical direction, a pad 59 having fluidity, a base portion 54 supporting the pad 59, a connecting member 57 connecting the arm portion 51 and the base portion 54, and an arm. The stoppers 53a and 53b (see FIG. 6 described later) provided in the portion 51, and the vibration generator 55 and the piping unit 56 provided in the base 54 are provided.

As shown in FIG. 2, the arm portion 51 has a columnar shape extending along the vertical direction. The base end portion of the arm portion 51 is slidably supported by the gripper main body 6 along the gripping direction. Of the tip portions 51a of the arm portion 51, the connecting member 57 is fixed to the inside along the gripping direction, and the two stopper support arms 52a extending in the vertical direction to the outside along the gripping direction, 52b is fixed.

FIG. 6 is a perspective view showing the configurations of the piping unit 56 and the stopper support arms 52a and 52b of the right arm unit 5R. Note that in FIG. 6, the vibration generator 55 is not shown for ease of understanding. FIG. 7 is a cross-sectional view of the base 54 and the piping unit 56 along the line VII-VII in FIG.

The stopper support arms 52a and 52b are columnar extending along the vertical direction. The base end portions of the stopper support arms 52a and 52b are fixed to the tip end portion 51a of the arm portion 51. Further, as shown in FIG. 6, columnar stoppers 53a and 53b are fixed at positions of the tips of the stopper support arms 52a and 52b facing the piping unit 56 described later along the gripping direction, respectively.

The connecting member 57 is a rectangular flat plate-shaped leaf spring extending along the vertical direction in a plane substantially perpendicular to the gripping direction, and elastically deforms along the gripping direction. The connecting member 57 is connected to the arm portion 51 and the base portion 54 on both sides in the extending direction thereof.

The base 54 has a rectangular flat plate shape extending along the vertical direction in a plane substantially perpendicular to the gripping direction. A first fixing portion 541 to which the connecting member 57 is fixed, a second fixing portion 542 to which the vibration generator 55 is fixed, and a piping unit 56 are fixed to the base portion 54 in order from the base end side to the tip end side. A third fixing portion 543 and a pad supporting portion 544 that supports the pad 59 are formed.

The pad support portion 544 has a substantially rectangular flat plate shape in a plan view. As shown in FIG. 7, a pad 59 is provided on the inner surface of the pad support portion 544 via a wire mesh 545 having a substantially rectangular shape in a plan view. Further, a substantially rectangular recess 546 is formed on the surface of the pad support portion 544 on the pad 59 side in a plan view. The recess 546 is filled with a porous body 547 that supports the wire mesh 545 and allows air to pass through the inside thereof. For this porous body 547, for example, foamed metal is used.

The pad 59 includes a sheet-shaped bag member 591 that covers the wire mesh 545 provided on the pad support portion 544, and a substantially rectangular frame member 592 that fixes the edge portion of the bag member 591 to the outer peripheral edge portion of the pad support portion 544. And the granular material 593 filled between the bag member 591 and the wire mesh 545. As the granular material 593, one having a particle size larger than that of the above-mentioned wire mesh 545 is used. A granular metal is preferably used for the granular material 593. Further, for the bag member 591, for example, a sheet-shaped elastic material having elasticity, more specifically, a rubber sheet is used. By forming the pad 59 by covering the granular material 593 with the bag member 591 having elasticity in this way, a pad 59 having fluidity, that is, a pad 59 having a property of changing its shape when an external force is applied is formed. Will be done. Further, as described above, a wire mesh 545 is provided between the pad 59 and the pad support portion 544. Therefore, air can flow between the inside of the pad 59 and the recess 546.

As shown in FIGS. 4 and 7, inside the base 54, the piping unit 56 extends from the third fixing portion 543 to which the piping unit 56 is fixed along the extending direction of the base 54, and reaches the recess 546 of the pad support portion 544. Two first air flow paths 548 and 549 are formed.

The vibration generator 55 is connected to a rectangular parallelepiped housing 551 fixed to the second fixing portion 542, a motor 552 (see FIG. 4) that rotates in response to a command signal from the control device 9, and a shaft of the motor 552. It is equipped with an eccentric weight (not shown). The motor 552 is provided inside the housing 551 so that the shaft is substantially perpendicular to the gripping direction and the extending direction of the base 54. The vibration generator 55 vibrates the housing 551 and the base 54 to which the housing 551 is fixed by rotating the motor 552 to which the eccentric weight is connected in response to a command from the control device 9, and is thus fixed to the base 54. The pad 59 is vibrated.

The piping unit 56 includes a piping connection portion 560 fixed to the third fixing portion 543 and two L-shaped air pipes 563 and 564. As shown in FIGS. 4, 6 and 7, the pipe connection portion 560 has a columnar shape, and two second air flow paths 561, 562 extending along the gripping direction are formed therein. .. One end side of these second air flow paths 561,562 communicates with the first air flow paths 548,549 formed inside the base portion 54. Air pipes 563 and 564 are connected to the other ends of the second air flow paths 561,562, respectively. Further, a vacuum pump 4 (see FIG. 1) that operates in response to a command from the control device 9 is connected to these air pipes 563 and 564.

Therefore, the inside of the pad 59 and the vacuum pump 4 pass through the wire mesh 545, the recess 546, the first air flow path 548,549, the second air flow path 561,562, and the air pipe 563,564. Be connected. Therefore, by driving the vacuum pump 4 by the control device 9 and discharging the air in the pad 59 from the air pipes 563 and 564, the pressure in the pad 59 can be reduced and the pad 59 can be hardened. Here, the hardness of the pad 59 can be continuously changed by adjusting the rotation speed of the vacuum pump 4 by the control device 9. Further, the pad 59 can be softened by stopping the driving of the vacuum pump 4 and opening the inside of the pad 59 to the atmospheric pressure. From the above, in the present embodiment, the curing means for changing the hardness of the pad 59 having fluidity is composed of the vacuum pump 4 and the control device 9 for driving the vacuum pump 4.

As shown in FIGS. 3 and 6, the pipe connecting portion 560 is fixed at a position of the base portion 54 facing the stoppers 53a and 53b along the gripping direction. Further, in a state where the connecting member 57 is not deformed, a slight gap 565 or 566 is formed between the pipe connecting portion 560 and the stoppers 53a and 53b along the gripping direction. That is, when the connecting member 57 is not deformed, the pipe connecting portion 560 and the stoppers 53a and 53b are not in contact with each other. Therefore, the base portion 54 is swingably supported by the arm portion 51 and the connecting member 57 along the gripping direction. Further, when the base portion 54 is pushed outward along the gripping direction to deform the connecting member 57, the pipe connecting portion 560 and the stoppers 53a and 53b come into contact with each other. Therefore, the movement of the base 54 outward along the gripping direction is restricted by the stoppers 53a and 53b.

Further, for example, as shown in FIG. 3, the stoppers 53a and 53b are provided at positions farther from the connecting member 57 than the vibration generator 55. As a result, the pad 59 can be efficiently vibrated by the vibration generated by the vibration generator 55.

Returning to FIG. 1, the roller unit 8 is based on a base 81 provided in the vicinity of the transfer robot 3 and the gripping device 5, a plurality of (for example, four) columnar rollers 82, and both ends of the rollers 82. A support portion 83 that rotatably supports the table 81 is provided. The roller unit 8 smoothes the surfaces of the pads 59 and 59 by rolling the plurality of rollers 82 along the surfaces of the pads 59 and 59 provided on the arm units 5L and 5R.

Next, a procedure for transporting the work W placed on the carriage 11 to the serving table 12 by using the transfer robot 3 and the gripping device 5 as described above will be described.

FIG. 8 is a diagram schematically showing a procedure for transporting a work.
First, in S1, the control device drives the transfer robot to bring the gripping device 5 closer to the work W provided on the carriage 11 from above. In the step of bringing the gripping device 5 closer to the work W, it is preferable that the control device drives the vacuum pump 4 to create a weak vacuum in the pads 59 and 59. In the present embodiment, the weak vacuum is a pressure that can maintain the hardness of the pads 59 and 59 to such an extent that they are not deformed by gravity or impact acting when the gripping device 5 is moved. For example, it is about 10 [kPa] higher than the atmospheric pressure. Not so low.

Next, in S2, the control device closes the arm units 5L and 5R by driving the gripper main body 6 while maintaining the inside of the pads 59 and 59 in a weak vacuum, and holds the pads 59 and 59 from both sides with a predetermined gripping force. Press it against the work W.

Next, in S3, the control device changes the shapes of the pads 59 and 59 according to the shape of the work W. More specifically, the control device drives the vibration generator after opening the pads 59 and 59 to atmospheric pressure from the state where the pads 59 and 59 are pressed against the work W with a predetermined gripping force from both sides. By vibrating the pads 59 and 59 and further pressing the pads 59 and 59 against the work W, the shapes of the pads 59 and 59 are changed according to the shape of the work W.

Next, in S4, the control device cures the pads 59 and 59 in a state where the shapes of the pads 59 and 59 are changed according to the shape of the work W, and the work W is determined by the cured pads 59 and 59. Grip with gripping force. More specifically, the control device drives the vacuum pump 4 while pressing the pads 59 and 59 against the work W with a predetermined gripping force to create a strong vacuum inside the pads 59 and 59 even lower than the weak vacuum. To do. In the present embodiment, the strong vacuum means a state in which the degree of vacuum is higher than the above-mentioned weak vacuum. More specifically, in the present embodiment, the strong vacuum is a pressure capable of maintaining the hardness of the pads 59 and 59 to such an extent that they are not deformed by an impact acting when gripping the work W under a predetermined gripping force. For example, it is about 85 [kPa] lower than the atmospheric pressure.

Next, in S5, the control device transfers the gripping device 5 and the work W gripped by the gripping device 5 to the serving table 12 by driving the transfer robot, and then drives the gripper main body 6 to drive the arm unit 5L, Open 5R and place the work W on the serving table 12.

Next, in S6, the control device drives the transfer robot to retract the gripping device 5 upward from the work W and opens the pads 59 and 59 to atmospheric pressure. As a result, as shown in FIG. 8, the pads 59 and 59 are deformed by their own weight.

Next, in S7, the control device drives the transfer robot to bring the gripping device 5 closer to the roller unit 8, and then rolls the rollers 82, 82 along the surfaces of the pads 59, 59 to bring the gripping device 5 closer to the roller unit 8. After leveling the surface of 59, the process returns to S1 and the new work W is gripped by using the pads 59 and 59 whose surface is leveled.

FIG. 9 is a diagram showing the step of S7, that is, the procedure of leveling the surfaces of the pads 59 and 59 by the roller unit 8.

First, as shown in FIG. 9A, the control device drives the transfer robot to bring the gripping device 5 closer to the upper side of the roller unit 8. At this time, the control device approaches the gripping device 5 from the upper side in the vertical direction of the rollers 82, 82 in a posture in which the rotation axes of the rollers 82, 82 are orthogonal to the gripping direction.

Next, the control device drives the transfer robot while fixing the distance between the two arm units 5L and 5R along the gripping direction, thereby moving the gripping device 5 vertically downward as shown in FIG. 9B. And roll each roller 82, 82 along the surface of each pad 59, 59. As a result, the surfaces of the rollers 82 and 82 are brought into contact with the surfaces of the pads 59 and 59 from the lower end side to the upper end side along the vertical direction of the surfaces of the pads 59 and 59. Can be rolled along. Further, as shown in FIG. 9 (c), when the gripping device 5 is further moved downward in the vertical direction and the rollers 82 and 82 pass through the surfaces of the pads 59 and 59, the surfaces of the pads 59 and 59 are changed. It is leveled flat and the thickness is constant.

When the surface of the pads 59 and 59 is leveled by the roller unit 8 as described above, it is preferable that the control device drives the vacuum pump to create a weak vacuum inside the pads 59 and 59. In other words, in the step of leveling the pads 59, 59, the control device uses a vacuum pump to change the hardness of the pads 59, 59 and the shape of the pads 59, 59 according to the shape of the work W. It is preferable that it is harder than (see S3) and softer than the step of curing the pads 59 and 59 (see S4).

Further, FIG. 9 has described a case where the distance between the two arm units 5L and 5R is fixed along the gripping direction in order to make the thicknesses of the pads 59 and 59 constant, but the present invention is not limited to this. More specifically, with the pads 59 and 59 pressed against the surfaces of the rollers 82 and 82, the pads 59 and 59 are moved downward in the vertical direction in the gripping direction of both arm units 5L and 5R. The spacing along may be varied.

For example, when the shape of each pad 59, 59 is made into a thickened shape as shown in FIG. 10A, that is, when the thickness of each pad 59, 59 is gradually reduced from the lower end side to the upper end side along the vertical direction. In the state where the pads 59 and 59 are pressed against the surfaces of the rollers 82 and 82, the pads 59 and 59 are moved downward in the vertical direction, and the distance between the two arm units 5L and 5R along the gripping direction. Should be gradually shortened. The thickened pads 59 and 59 as shown in FIG. 10A are suitable for stably gripping a heavy workpiece.

Further, for example, when the shape of each pad 59, 59 is tapered as shown in FIG. 10B, that is, when the thickness of each pad 59, 59 is gradually increased from the lower end side to the upper end side along the vertical direction. In the state where the pads 59 and 59 are pressed against the surfaces of the rollers 82 and 82, the pads 59 and 59 are moved downward in the vertical direction, and the distance between the two arm units 5L and 5R along the gripping direction. Should be gradually lengthened. The tapered pads 59, 59 as shown in FIG. 10B are suitable for gripping a work in a narrow space.

According to the gripping device 5 and the control method thereof according to the present embodiment, the following effects are obtained.
(1) The gripping device 5 has an arm unit 5L, 5R, a gripper main body 6 that opens and closes the arm portions 51, 51 of the arm units 5L, 5R along the gripping direction, and the arm unit 5L having fluidity. , 5R, the pads 59, 59, the vacuum pump 4 and the control device 9 for changing the hardness of the pads 59, 59, and the rollers 82, 82 are rolled along the surface of the pads 59, 59 to make the pads 59. , 59 is provided with a roller unit 8 for leveling the surface. According to the gripping device 5, the pads 59 and 59 can be thinned by leveling the surfaces of the pads 59 and 59 using the roller unit 8, so that even if there is not enough space on the side of the work W, these pads 59 and 59 can be made thin. The pads 59 and 59 are inserted, and the work W can be gripped by these pads 59 and 59. Further, according to the gripping device 5, the surfaces of the pads 59 and 59 are leveled by using the roller unit 8 before the pads 59 and 59 are deformed according to the shape of the work W, so that the pads 59 and 59 and the work are smoothed. Since the contact area of W can be increased, the gripping force of the pads 59 and 59 can be increased.

(2) The control device 9 follows the gripping directions of the arm units 5L and 5R while moving the pads 59 and 59 in the vertical direction with the pads 59 and 59 pressed against the surfaces of the rollers 82 and 82. Change the interval. Thereby, the thickness of the pads 59, 59 along the gripping direction can be changed along the vertical direction. Further, by this, the profile shape along the vertical direction of the thickness of the pads 59 and 59 can be set so that the work W can be gripped in an appropriate manner according to the characteristics of the work W and the shape of the space on the side of the work W. it can.

(3) The pads 59 and 59 tend to sag on the lower end side in the vertical direction due to their own weight. On the other hand, the control device 9 puts the rollers 82, 82 on the pads 59, 82 so that the surfaces of the rollers 82, 82 abut on the surfaces of the pads 59, 59 in order from the lower end side to the upper end side along the vertical direction. Roll along the surface of 59. As a result, the surfaces of the pads 59 and 59 can be leveled by gathering the slack portions on the lower end side.

(4) In the gripping device 5, when the control device 9 smoothes the surfaces of the pads 59 and 59 by the roller unit 8, the hardness of the pads 59 and 59 and the shape of the pads 59 and 59 are changed to the shape of the work W. It is made harder than when it is changed according to the above and softer than when the work W is gripped by the pads 59 and 59. As a result, the surfaces of the pads 59 and 59 can be appropriately leveled by the roller unit 8 and the shape after leveling can be maintained. Further, by changing the hardness of the pads 59 and 59 as described above, when the shape of the pads 59 and 59 is changed, it can be changed so as to follow the uneven shape of the work W, and the work W is gripped. In some cases, it can be firmly gripped.

(5) The gripping device 5 smoothes the surfaces of the pads 59, 59 by rolling the rollers 82, 82 along the surfaces of the pads 59, 59 having fluidity, and then works the smoothed pads 59, 59. By approaching W, the work W is gripped by the pads 59 and 59. As a result, the surfaces of the pads 59 and 59 can be leveled and the pads 59 and 59 can be made thin. Therefore, even if there is not enough space on the side of the work W, the pads 59 and 59 can be inserted and these pads 59 and 59 can be inserted. The work W can be gripped by the 59. Further, the gripping device 5 can increase the contact area between the pads 59 and 59 and the work W by leveling the surfaces of the pads 59 and 59 before gripping the work W with the pads 59 and 59. The gripping force of the pads 59 and 59 can be increased.

(6) The gripping device 5 follows the shape of the pads 59 and 59 according to the shape of the work W by leveling the surfaces of the pads 59 and 59 (S7) and then pressing the pads 59 and 59 against the work W while vibrating. After the change (S3), the pads 59 and 59 are cured in a state where the shapes of the pads 59 and 59 are changed according to the shape of the work W, and the work W is gripped (S4). Further, the gripping device 5 is harder than when the hardness of the pads 59, 59 is changed when the surfaces of the pads 59, 59 are leveled, and the shape of the pads 59, 59 is changed according to the shape of the work W, and the pads 59, It is made softer than when gripping the work W at 59. As a result, the surfaces of the pads 59 and 59 can be appropriately leveled, and the shape after leveling can be maintained. Further, by changing the hardness of the pads 59 and 59 in each step as described above, the pads 59 and 59 can be deformed so as to follow the uneven shape of the work W, and the work W can be firmly gripped. Can be done.

Although one embodiment of the present invention has been described above, the present invention is not limited to this. Within the scope of the gist of the present invention, the detailed configuration may be changed as appropriate.

For example, in the above embodiment, the case where a single leaf spring is used as the connecting member for connecting the arm portion and the base portion has been described, but the present invention is not limited to this. The connecting member may be replaced with the connecting member of Modifications 1 to 3 shown below.

FIG. 11A is a side view of the connecting member 57A of the modified example 1 viewed along a direction perpendicular to the gripping direction. The connecting member 57A of the first modification is composed of two rectangular flat plate-shaped first leaf springs 571A and second leaf springs 572A extending along the vertical direction in a plane substantially perpendicular to the gripping direction. The first leaf spring 571A and the second leaf spring 57 2A are provided in parallel with each other via a spacer 573A having the same thickness as the first fixing portion 541 of the base portion 54. These leaf springs 571A and 572A are elastically deformed along the gripping direction. These leaf springs 571A and 572A are connected to the tip portion 51a of the arm portion 51 and the first fixing portion 541 of the base portion 54 on both sides in the extending direction thereof. As a result, the base portion 54 is swingably supported by the arm portion 51 and the connecting member 57A along the gripping direction.

FIG. 11B is a side view of the connecting member 57B of the modified example 2 viewed along a direction perpendicular to the gripping direction. The connecting member 57B of the modified example 2 includes a bracket 571B connected to the tip end portion 51a of the arm portion 51, two links 577B and 578B connecting the bracket 571B and the first fixing portion 541 of the base portion 54, and a bracket. It includes two springs 575B, 576B inserted between the 571B and the links 577B, 578B.

The bracket 571B is substantially C-shaped when viewed from the side, and includes an upper portion 572B extending along the gripping direction and two side walls 573B and 574B extending in a direction orthogonal to the upper portion 572B. The links 577B and 578B extend parallel to each other. Both ends of the links 577B and 578B are rotatably supported on the upper portion 572B and the first fixing portion 541 via a rotation shaft, respectively. The spring 575B is stretchably inserted between the side wall 573B and the link 577B along the gripping direction. The spring 576B is stretchably inserted between the side wall 574B and the link 578B along the gripping direction. Further, in a state where no load is applied to the base portion 54, that is, in a state where the springs 575B and 576B have natural lengths, the links 577B and 578B are parallel to the vertical direction substantially perpendicular to the gripping direction. As a result, the base portion 54 is swingably supported by the arm portion 51 and the connecting member 57B along the gripping direction.

FIG. 11C is a side view of the connecting member 57C of the modified example 3 viewed along a direction perpendicular to the gripping direction. The connecting member 57C of the third modification is the four linear bushes 574C, 575C, 576C that connect the bracket 571C connected to the tip end portion 51a of the arm portion 51, and the bracket 571B and the first fixing portion 541 of the base portion 54. , 577C and four springs 578C, 579C, 580C, 581C inserted between the linear bushes 574C to 577C and the first fixing portion 541.

The bracket 571C is substantially C-shaped when viewed from the side, and includes an upper portion extending along the gripping direction and two side walls 572C and 573C extending in a direction orthogonal to the upper portion. The linear bushes 574C and 575C each include an outer cylinder fixed to the side wall 572C and a shaft slidably supported by the outer cylinder along the gripping direction. The linear bushes 576C and 577C each include an outer cylinder fixed to the side wall 573C and a shaft slidably supported by the outer cylinder along the gripping direction. Further, the linear bushes 574C and 575C face each other with the linear bushes 576C and 577C sandwiching the first fixing portion 541, respectively. The tip of the shaft of each of the linear bushes 574C to 577C abuts on the first fixing portion 541.

The springs 578C to 581C are inserted into the shafts of the linear bushes 574C to 577C, respectively. The springs 578C to 581C are inserted and contractably inserted between the first fixing portion 541 and the outer cylinders of the linear bushes 574C to 577C along the gripping direction. Further, in a state where no load is applied to the base portion 54, that is, in a state where the springs 578C to 581C have natural lengths, the base portion 54 is substantially parallel to the side walls 572C and 573C. As a result, the base portion 54 is swingably supported by the arm portion 51 and the connecting member 57C along the gripping direction.

Further, for example, in the above embodiment, the case where the roller unit 8 is provided at a position away from the gripping device 5 has been described, but the present invention is not limited to this.

FIG. 12A is a diagram showing an example when the roller unit 8A is fixed to the gripper main body 6 of the gripping device 5A. The roller unit 8A rotatably supports a plurality of (for example, four) columnar rollers 82A extending along a direction orthogonal to the gripping direction, and both ends of these rollers 82A between the arm units 5L and 5R. A support portion 83A and an actuator 84A that moves the support portion 83A forward and backward along the extending direction of the arm units 5L and 5R with respect to the gripper main body 6 in response to a command from the control device are provided.

According to the gripping device 5A, as shown in FIG. 12B, the support portion 83A is moved from the lower side to the upper side in the vertical direction while fixing the distance between the arm units 5L and 5R along the gripping direction, and the rollers 82A, respectively. By rolling 82A along the surface of each pad 59, 59, the surface of each pad 59, 59 can be leveled.

S ... Work transfer system W ... Work 3 ... Transfer robot (leveling means)
4 ... Vacuum pump (curing means)
5 ... Gripping device 5L ... Left arm unit 5R ... Right arm unit 51 ... Arm part 6 ... Gripper body (main body)
8,8A ... Roller unit (leveling means)
82, 82A ... Roller 9 ... Control device (curing means, leveling means)

Claims (6)

A gripping device that grips a work
With multiple arms
A main body that opens and closes the plurality of arm portions along the gripping direction, and
A pad having fluidity and provided at least one of the plurality of arm portions,
A curing means for changing the hardness of the pad and
A gripping device comprising: a leveling means for leveling the surface of the pad by rolling a roller along the surface of the pad. The roller is rotatable about an axis substantially perpendicular to the gripping direction.
In the leveling means, with the pad pressed against the surface of the roller, the pad and / or the roller are moved along the gripping direction and the sliding direction substantially perpendicular to the axis. The gripping device according to claim 1, wherein the position of the arm portion is changed along the gripping direction. The leveling means rolls the roller along the surface of the pad so that the surface of the roller abuts on the surface of the pad in order from the lower end side to the upper end side along the vertical direction. The gripping device according to claim 1 or 2. When the surface of the pad is leveled by the leveling means, the curing means is harder than when the shape of the pad is changed according to the shape of the work and the pad is used. The gripping device according to any one of claims 1 to 3, wherein the work is made softer than when gripping the work. With multiple arms
A main body that opens and closes the plurality of arm portions along the gripping direction, and
A pad having fluidity and provided at least one of the plurality of arm portions,
A method for controlling a gripping device, which comprises a curing means for changing the hardness of the pad and grips the work by pressing the pad against the work.
A leveling step of leveling the surface of the pad by rolling a roller along the surface of the pad.
A method for controlling a gripping device, comprising: a gripping step of gripping the work with the pad by bringing the pad whose surface is leveled by the roller close to the work. The gripping step is
A deformation step of changing the shape of the pad according to the shape of the work by pressing the pad against the work while vibrating the pad.
The pad is cured in a state where the shape of the pad is changed according to the shape of the work, and the work is gripped by the cured pad.
The control method for a gripping device according to claim 5, wherein in the leveling step, the hardness of the pad is made harder than the deformation step and softer than the hardening step by using the hardening means. ..

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