JP2010155331A - Vacuum-type suction device and robot hand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a suction error resulting from a turn-up phenomenon of a vacuum cup even when an inclined section of an opposite side member is sucked. <P>SOLUTION: The vacuum-type suction device : a cylinder tube 8; a piston 9; a piston rod 10 with a negative pressure path 13 formed therein; a vacuum cup 11; and a communication path 14 disposed in an inner periphery of the cylinder tube 8. In the state shown in (A) where the piston 9 does not conform with the communication path 14, the negative pressure is introduced through the negative pressure path 13. This allows the vacuum cup 11 together with the cylinder tube 8 to move by a stroke S from the piston 9 side as a fixed side, and the vacuum cup 11 is pressed to a workpiece W as shown in (B). Thus, the piston 9 conforms with the communication path 14 so that the workpiece W is sucked and supported by the negative pressure suction force. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vacuum suction device for sucking and supporting a workpiece in various production lines, for example, and a robot hand using the suction device.

  For example, when a robot hand with a vacuum cup (vacuum pad) is approached from a direction perpendicular to the surface of a panel-shaped workpiece, the workpiece is sucked and supported, and then transferred to a predetermined position. Even if the shape is flat, it may be necessary to suck and support a specific portion of the workpiece that is inclined due to the weight balance when sucking and supporting the vacuum cup.

  In such a case, it is set in advance so that the inclined part on the workpiece side and the suction surface on the vacuum cup side are parallel to each other, and the approach direction of the robot hand itself to the workpiece is the first regardless of the inclined part. The workpiece is supported by suction from the stated direction.

  Patent Documents 1 and 2 propose vacuum suction devices suitable for suction support of such workpieces. In those described in Patent Documents 1 and 2, the vacuum cup can perform a stroke operation independently, and has a function of lifting the workpiece by a predetermined amount simultaneously with the suction of the workpiece by the vacuum cup.

Japanese Utility Model Publication No. 63-151459 Japanese Utility Model Publication No. 7-33588

  However, in the workpiece suction support mode as described above, although the inclined portion on the workpiece side and the suction surface on the vacuum cup side are set in advance, the approach direction of the robot hand itself to the workpiece is first. From the direction described in. Therefore, the approach direction of the vacuum cup with respect to the part to be adsorbed on the workpiece side, that is, the inclined part on the workpiece side is not from the direction perpendicular to the inclined part. Approach action from an acute angle. As a result, a turn-up phenomenon occurs at the end of the vacuum cup due to the influence of the approach locus of the vacuum cup, and there is a possibility that a suction error will occur.

  In addition, the angle of the inclined part on the workpiece side that can be attracted by the vacuum cup is limited to about 40 ° with respect to the general surface of the workpiece, and if the inclination angle becomes larger than that, the suction method using the vacuum cup is replaced with a clamp or jaw. It is necessary to adopt a so-called grip-type hand. In this case, as compared with the suction method using a vacuum cup, the time required from gripping the workpiece to conveyance becomes longer, which is not preferable because the conveyance speed is lowered.

  The present invention has been made paying attention to such a problem, and as described above, even when the inclined portion of the counterpart member has to be adsorbed by a vacuum cup, the adsorbed by the turning-up phenomenon The present invention provides a vacuum suction device and a robot hand that are capable of attracting a counterpart member more reliably without causing a mistake.

  In the present invention, in order to achieve the intended purpose, for example, even when the inclined portion of the mating member must be sucked by the vacuum cup, the vacuum cup capable of stroke operation is sucked by the mating member. The structure is such that the portion to be attracted is approached from the direction perpendicular to the surface to be attracted.

  According to the present invention, for example, even when the inclined part of the counterpart member has to be adsorbed by a vacuum cup, the vacuum cup approaches the part to be adsorbed from the direction perpendicular to the surface, There is no occurrence of a vacuum cup turning-up phenomenon and a suction error associated therewith, resulting in high reliability.

  In addition, since the number of parts is small, the structure of the entire apparatus can be simplified, and control of another pneumatic system other than the introduction of negative pressure is unnecessary, so that simplification of control can be achieved.

It is a figure which shows more concrete embodiment of this invention, and is schematic explanatory drawing of the whole robot hand. FIG. 2 is a diagram showing details of the vacuum suction device alone in the robot hand shown in FIG. 1, in which (A) is a cross-sectional view showing a state before negative pressure is introduced, and (B) in FIG. Sectional drawing which shows the state after a negative pressure is introduced from the state of. The expanded sectional view which follows the aa line of (B) of FIG. Sectional drawing which expanded the B section of the same figure as the detail of the vacuum-type adsorption | suction apparatus in the robot hand shown in FIG. It is a figure which shows the locus | trajectory of the approach operation | movement of the vacuum cup with respect to a workpiece | work, (A) is explanatory drawing of the locus | trajectory of a prior art example, The same figure (B) is explanatory drawing which shows the locus | trajectory with the robot hand of FIG.

  1 to 4 show a more specific embodiment of the present invention. In particular, FIG. 1 shows an overall schematic configuration of a vacuum cup type robot hand (hereinafter simply referred to as “hand”) 2. .

  In the present embodiment, as shown in FIG. 1, an embossed portion E is formed on a panel-shaped workpiece W as a counterpart member, for example, along the longitudinal direction (in FIG. 1, the direction orthogonal to the paper surface). Then, the entire workpiece W is sucked and supported by using the inclined surface Q of the embossed portion E as a portion to be sucked, and then conveyed by the autonomous operation of the robot.

  A hand 2 is attached to the tip of a robot arm 1 of an industrial robot that functions as a transport mother machine. The hand 2 has a plurality of vacuum suction devices 6 mounted on a common frame 3 as a support supported by the robot arm 1 via extension brackets 4 and 5. Here, a pair of vacuum suction devices 6 arranged so as to be symmetric is set as a pair, and a plurality of sets of vacuum suction devices 6 are arranged along the longitudinal direction of the workpiece W (in the direction orthogonal to the paper surface in FIG. 1). It is set up.

  FIG. 2 shows details of the vacuum suction device 6 alone, and it can be understood that the vacuum cylinder 11 made of a flexible member such as rubber is combined with a special air cylinder 7 as will be described later. it can.

  As shown in FIG. 1A, the cylinder tube 8 of the air cylinder 7 has a cylindrical shape with one end opened, and a slidable piston 9 and a piston integrally connected to the piston 9 are inside. The rod 10 is housed and arranged in a concentric manner, and the piston rod 10 protrudes from the cylinder tube 8. The cylinder 7 is formed by the cylinder tube 8, the piston 9, and the piston rod 10, and the presence of the piston 9 makes the inside of the cylinder tube 8 an open end side space R <b> 1 and an anti-open end side space R <b> 2. It is divided into and. Although not shown in FIG. 2, a seal member such as an O-ring is interposed in a sliding portion on the piston 9 side with respect to the cylinder tube 8.

  Further, an annular vacuum cup 11 is attached to one end of the cylinder tube 8 on the open side, and is fastened and fixed by, for example, a ring-shaped retainer 12 screwed to the open end of the cylinder tube 8. is there. As shown in FIG. 1, the vacuum suction device 6 as a whole is fixedly supported on the frame 3 via extension brackets 4 and 5 with the piston rod 10 as a fixed side.

  Here, as will be described later with reference to FIGS. 1 and 4, it is assumed that the hand 2 is approached and supported by suction from a direction perpendicular to the surface of the workpiece W waiting in a so-called flat state. Therefore, the approach operation of the entire hand 2 is set to stop immediately before the vacuum cup 11 comes into contact with the workpiece W. At the stop position of the approach operation, the extension brackets 4, 5 are tilted with the vacuum suction device 6 tilted so that the suction surface 11 a at the tip of the vacuum cup 11 is parallel to the inclined surface Q on the workpiece W side. Etc., and is fixed to the frame 3.

  A negative pressure passage 13 is formed along the longitudinal direction of the piston rod 10 shown in FIG. The negative pressure passage 13 is always in communication with the non-open end-side space R2 via a port 13a close to the piston 9, and the other end of the negative pressure passage 13 is connected to a negative pressure supply source (not shown). . The negative pressure passage 13 does not necessarily have to be formed in the piston rod 10, and the point is that the negative pressure may be introduced into the space R <b> 2 on the side opposite to the opening in the cylinder tube 8. For example, instead of forming the negative pressure passage 13 in the piston rod 10, it is also possible to introduce a negative pressure directly into the space R <b> 2 on the side opposite to the opening in the cylinder tube 8 using a hose or the like.

  Further, at the intermediate position in the axial direction on the inner peripheral surface of the cylinder tube 8 shown in FIG. 2A, as shown in FIG. The communication path 14 is formed. The length H in the axial direction of the communication path 14 is set to be larger than the thickness M of the piston 9 (H> M). As shown in FIG. 2A, when the piston 9 does not coincide with the position of the communication path 14, the piston 9 moves the internal space of the cylinder tube 8 between the open end side space R1 and the anti-open end side. A space R2 is formed in isolation. On the other hand, as shown in FIG. 2B, in the state where the piston 9 is in a position that coincides with the position of the communication path 14, the open end that is the internal space of the cylinder tube 8 is bypassed. The space R1 on the side and the space R2 on the side opposite to the open end communicate with each other via the communication path 14.

  A return spring 15 made of a compression coil spring is disposed in the space R2 on the side opposite to the open end in the cylinder tube 8. A stopper 12a is formed on the inner periphery of the retainer 12, and a boss-like stopper 8a is formed on the inner bottom of the cylinder tube 8. The cylinder tube 8 is formed by these stoppers 12a and 8a. The piston 9 is prevented from coming off and the stroke of the piston 9 itself is restricted.

  According to the hand 2 configured as described above, when the panel-like workpiece W having the embossed portion E is sucked and supported as shown in FIG. It is assumed that the hand 2 is approached and supported by suction from a direction perpendicular to the plane directly above. At this time, no vacuum is introduced into the space R2 on the side opposite to the opening in the cylinder tube 8 in the vacuum suction device 6, and the spring force of the return spring 15 is applied, so that the vacuum cup 11 is attached. The cylinder tube 8 and the piston 9 maintain the relative positional relationship shown in FIG. At this time, the position of the piston 9 is regulated by contact with the stopper portion 12a.

  As a means for maintaining the relative positional relationship between the cylinder tube 8 and the piston 9 as shown in FIG. 2 (A), instead of the return spring 15, a space R2 on the side opposite to the opening end in the cylinder tube 8 is directly added. You may make it introduce the compressed air of pressure.

  Then, the position C immediately before the vacuum cup 11 contacts the inclined surface Q that is the suction portion on the workpiece W side, for example, the distance C between the suction surface 11a at the tip of the vacuum cup 11 and the inclined surface Q as shown in FIG. It is assumed that the approach operation of the entire hand 2 is stopped when approaching 5 to 10 mm. The distance C is naturally determined in consideration of the stop position accuracy of the approach operation. At this time, as described above, the inclined surface Q on the workpiece W side and the suction surface 11a of the vacuum cup 11 are not in contact with each other and are parallel to each other.

  In FIG. 4, the retainer 12, the stopper portion 12a, the stopper portion 8a, etc. shown in FIG. 2 are not shown.

  If the hand 2 stops at the approach operation stop position and the relative positional relationship between the inclined surface Q on the workpiece W side and the suction surface 11a of the vacuum cup 11 becomes as shown in FIG. The negative pressure is introduced into the space R2 on the side opposite to the open end in the cylinder tube 8 through (A) of FIG.

  With the introduction of the negative pressure into the space R2 on the side opposite to the open end, the relative positional relationship between the cylinder tube 8 with the vacuum cup 11 and the piston 9 changes from the state shown in FIG. It changes to the state. That is, when negative pressure is introduced into the space R2 on the opposite side in FIG. 2A, the piston 9 is fixed to the frame 3 side in FIG. In order to reduce the volume, the cylinder tube 8 with the vacuum cup 11 moves against the piston 9 and the piston rod 10 against the spring force of the return spring 15 under the stroke S in FIG. Relative movement). The stroke operation of the cylinder tube 8 is nothing but the approach or advance operation of the vacuum cup 11 with respect to the inclined surface Q on the workpiece W side. As a result, the vacuum cup 11 is bent and deformed as shown in FIG. It is pressed against the inclined surface Q on the W side.

  In this case, until the piston 9 matches the communication path 14, the negative pressure acts only on the cylinder tube 8 on the movable side and is not consumed as the suction force for attracting the workpiece W. It is possible to perform the stroke operation with the cylinder tube 8 by a predetermined stroke S with certainty.

  In addition, said stroke S is determined according to the deformation amount etc. of the vacuum cup 11, for example. Further, the position and the number of the communication passages 14 are determined according to the magnitude of the negative pressure, the stroke S and the like. In other words, it is possible to adjust the stroke S by adjusting the position of the communication path 14.

  In this case, the vacuum cup 11 moves toward or advances from the direction perpendicular to the inclined surface Q on the workpiece W side while being guided by the piston rod 10 together with the cylinder tube 8. There is no turning phenomenon.

  Then, in the process in which the vacuum cup 11 is pressed against the inclined surface Q on the workpiece W side as described above, the piston 9 eventually becomes the position of the communication path 14 on the inner periphery of the cylinder tube 8 as shown in FIG. To match. Note that the position of the piston 9 at this time is regulated by contact with the stopper portion 8a.

  When the piston 9 and the communication path 14 are matched, the space R2 on the side opposite to the open end in the cylinder tube 8 and the space R1 on the open end side are mutually connected via the communication path 14 so as to bypass the piston 9. Communicate. At this time, the space R1 on the open end side in the cylinder tube 8 has already been sealed by contact with the inclined surface Q together with the internal space of the vacuum cup 11, so that the space R1 on the open end side in the cylinder tube 8 and A negative pressure equivalent to the space R2 on the side opposite to the open end acts on the internal space of the vacuum cup 11 as well. As a result, the workpiece W is sucked and supported by the negative pressure suction force of the vacuum cup 11 with the inclined surface Q as the suction portion.

  Thereafter, when the vacuum cup 11 sucks and supports the workpiece W as described above, the vacuum cup 11 can maintain the state of FIG. 2B, and hence the workpiece supported by the entire hand 2 thereafter. W is transported to a predetermined position by the autonomous operation of the robot.

  When the workpiece W is released from the vacuum cup 11, the space R2 on the side opposite to the open end and the space R1 on the open end side in the cylinder tube 8 are opened to the atmosphere through the negative pressure passage 13, or replaced with negative pressure. Then, positively compressed air can be positively introduced to destroy the negative pressure state.

  Here, if the difference of the approach locus | trajectory of the vacuum cup 11 with respect to the workpiece | work W in a prior art example and this Embodiment is compared, it will become a thing as FIG. In addition, the code | symbol P of FIG. 5 shows the stop position of the approach operation | movement as the hand 2 whole as mentioned above.

  In the conventional example shown in FIG. 5A, the vacuum cup 11 approaches the workpiece W side inclined surface Q at an acute angle with a trajectory S1, so that, as described above, at the lower end of the vacuum cup 11 A turning phenomenon as indicated by the symbol F is likely to occur. In addition, if the angle θ of the inclined surface Q exceeds 40 °, suction support by the vacuum cup 11 becomes difficult.

  On the other hand, in the present embodiment, the approach operation of the hand 2 as a whole with respect to the workpiece W ends with the locus S2, but subsequently, the vacuum cup 11 alone moves with respect to the inclined surface Q on the workpiece W side. Since the approaching or advancing operation is performed from the direction perpendicular to the surface with S3, the turning-up phenomenon as described above does not occur, and the workpiece W can be reliably sucked and supported. Moreover, even if the angle θ of the inclined surface Q exceeds 40 °, the suction support by the vacuum cup 11 can be performed.

  Further, in the present embodiment, as is apparent from FIG. 2, the components of the vacuum suction device 6 are the minimum necessary, so that the structure can be simplified. Moreover, the ON / OFF control for introducing the negative pressure is basically the same as the conventional one, and the vacuum cup 11 can perform independent stroke operation without complicating the control. become.

  Here, in the above embodiment, the case where the vacuum suction device 6 is applied to the robot hand 2 is illustrated, but the vacuum suction device 6 can be applied to various suction supports other than the robot hand by itself. Needless to say.

1 ... Robot arm 2 ... Robot hand 3 ... Frame (support)
6 ... Vacuum type adsorption device 7 ... Cylinder 8 ... Cylinder tube 9 ... Piston 10 ... Piston rod 11 ... Vacuum cup 13 ... Negative pressure passage 14 ... Communication passage Q ... Inclined surface R1 ... Space on the open end side R2 ... Anti-open end side Space S ... Stroke W ... Workpiece (mating member)

Claims (8)

A cylinder tube with one end open;
A piston that is inserted into the cylinder tube and partitions the inside of the cylinder tube into a space on the open end side and a space on the non-open end side;
A piston rod connected to the piston;
A vacuum cup attached to the open end of the cylinder tube and capable of adsorbing the mating member by contacting the mating member;
A negative pressure passage communicating with the space on the non-open end side of the cylinder tube;
The cylinder tube is formed on the inner peripheral surface of the cylinder tube at an intermediate position in the axial direction, and when it matches the position of the piston according to the relative movement with the piston, it bypasses the piston and is opposite to the space on the open end side. A communication path communicating with the open end side space;
A vacuum type adsorption device comprising: When negative pressure is introduced into the space on the side opposite to the open end through the negative pressure passage when the piston does not match the communication path, the piston and the cylinder tube are relative to each other so as to reduce the volume of the space on the side opposite the open end. Move and
2. The vacuum suction device according to claim 1, wherein when the piston matches the communication path, the space on the side opposite to the open end and the space on the open end side are communicated with each other through the communication path. .   The vacuum suction device according to claim 2, wherein the piston is a fixed side, and a cylinder tube with a vacuum cup attached is a movable side, so that both move relative to each other. When negative pressure is introduced into the space on the side opposite to the open end through the negative pressure passage when the piston does not match the communication path, the cylinder tube relative to the piston is reduced so as to reduce the volume of the space on the side opposite to the open end. Strokes and
The vacuum suction device according to claim 3, wherein the vacuum cup is pressed against the counterpart member by the stroke operation of the cylinder tube.   When the piston matches the communication path by the stroke operation of the cylinder tube with respect to the piston, the opposite end side space and the open end side space are communicated with each other through the communication path, and the opposite member is adsorbed by the vacuum cup. The vacuum suction device according to claim 4, wherein the vacuum suction device is configured as described above.   Prior to the vacuum cup to adsorb the mating member when the piston is the fixed side and the cylinder tube with the vacuum cup attached is the movable side and negative pressure is introduced into the space on the non-open end side of the cylinder tube The vacuum suction device according to claim 1, wherein the vacuum cup moves in a stroke toward the mating member together with the cylinder tube.   A plurality of vacuum suction devices according to claim 5 or 6 are mounted on a common support so that the piston rod is on the fixed side, and the support is supported by a robot arm of an industrial robot as a base. A robot hand characterized by being. A robot hand that approaches the workpiece that is the counterpart member from the direction perpendicular to the surface and sucks and supports the workpiece,
Of the above work, the part to be sucked and supported by the vacuum cup is inclined, and the inclined part and the suction surface on the vacuum cup side are set in advance,
The approach movement of the robot hand is stopped immediately before the vacuum cup comes into contact with the workpiece, and at the approach movement stop position, the anti-open end is passed through the negative pressure passage while the piston does not match the communication passage. The robot hand according to claim 7, wherein introduction of negative pressure into the side space is started.

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