JP5592917B2 - Work gripping system - Google Patents

Description

  The present invention relates to a workpiece gripping system, and more particularly to a workpiece gripping system for gripping and transporting various workpieces by a workpiece gripping device mounted on a robot arm.

  In a production line in which a plurality of parts are processed and assembled to complete a product having various variations, a technique for gripping and transporting the workpiece in a flexible manner corresponding to a variety of workpieces is employed.

  For example, in the third page, lower left column, lines 10 to 14 of Patent Document 1, “the arrangement position of the three fingertip members is changed to an arrangement state suitable for holding according to the shape of the workpiece to be held. This provides a robot hand and a gripping method that can grip a workpiece reliably ”.

JP-A-4-82686

  However, in the robot hand described in Patent Document 1, three drive motors are installed to change the arrangement position of the three fingertip members, and the hand attached to the robot arm is large, heavy, and complicated. There is a problem of becoming. For this reason, there is a possibility of causing restrictions on the operation of the robot tip, an increase in power consumption, a failure, and the like.

  In addition, the robot hand described in Patent Document 1 is a pin member provided so as to be able to protrude from the fingertip member because the hand is larger and heavier when the workpiece is large and heavy, and is difficult to handle. Gripping a small and lightweight workpiece from the point of adopting a configuration for gripping the workpiece (see page 4, lower right column, lines 5-9, page 5, upper right column, line 20 to lower left column, line 5). However, it is thought that only.

  The present invention has been made in view of such circumstances, and can be flexibly adapted to various works with a single lightweight work gripping device attached to a robot arm, and can securely hold the work. It is an object of the present invention to provide a workpiece gripping system that can be transported.

In order to solve the above-mentioned problem, an invention according to claim 1 is provided on a support plate connected to a robot arm, the support plate, and abuts against a plurality of contacted portions of the work when gripping the work. A plurality of abutting portions for gripping a work, provided on the support plate, and having a drive source for generating a driving force for pressing at least one of the plurality of abutting portions against the work when gripping the work. A workpiece gripping device comprising: a drive mechanism; a free movement mechanism that supports at least one of the plurality of contact portions so as to be freely movable with respect to the support plate; and a movement restricting device that restricts free movement by the free movement mechanism. If the provided outside of the workpiece holding device, it possesses a contact portion moving drive device for moving the abutment part that is movably supported freely, wherein the movable mechanism, A nut member on which the abutting portion is disposed, and a screw shaft that is screwed into the nut member, and the abutting portion moving drive device includes a rotational driving device and a rotational force of the rotational driving device. a workpiece holding system, characterized by chromatic and a transmission shaft for transmitting to said screw shaft.

According to the present invention, since at least one of the plurality of abutting portions can be freely moved by the free movement mechanism, the abutting portion of the workpiece gripping device is previously aligned with the abutted portion of the workpiece. In addition, by holding the position by the movement restricting device, it is possible to flexibly cope with various workpieces having different shapes and sizes.
The alignment of the contact portion can be realized by using a contact portion moving drive device provided outside the workpiece gripping device. For this reason, the work gripping system according to the present invention reduces the weight of the work gripping device by providing the contact portion moving drive device for positioning the contact portion outside the work gripping device without providing the work gripping device. It is possible to cope with various workpieces having variations while realizing the above.
That is, it is possible to provide a workpiece gripping system that can flexibly handle various workpieces with a single lightweight workpiece gripping device attached to the robot arm and can securely hold and transport the workpiece.

  Further, the apparatus includes a plurality of abutting portions that respectively abut against the plurality of abutted portions of the workpiece when gripping the workpiece and grip the workpiece, and at least one of the plurality of abutting portions is driven by a driving force of a driving source. The outer surface or the inner surface of the workpiece can be gripped. Thereby, even if the workpiece gripping device is not accurately positioned with respect to the workpiece, the workpiece can be gripped. Therefore, in the manufacturing process, the work time can be shortened, and the occurrence of work mistakes in which the work cannot be gripped can be suppressed. Further, the workpiece can be reliably and easily gripped regardless of the size and weight of the workpiece. Furthermore, even if the shape of the workpiece is complicated, it is easy to hold the workpiece by securing a place where the contact portion of the workpiece gripping device contacts the outer surface or the inner surface of the workpiece, and the versatility is excellent.

Further , by transmitting the rotational force of the rotary drive device to the screw shaft through the transmission shaft, the contact portion can be moved in the axial direction of the screw shaft by the screw feeding action of the screw shaft and the nut member, The free movement mechanism can have a simple and compact configuration.

The invention according to claim 2 is the workpiece gripping system according to claim 1 , wherein the transmission shaft has a transmission shaft side engaging portion provided at an end portion on the screw shaft side, and the screw shaft is The screw shaft side engaging portion is engageable with the transmission shaft side engaging portion.

  According to the present invention, the rotational force of the rotary drive device can be transmitted to the screw shaft by a simple operation of engaging the screw shaft side engaging portion with the transmission shaft side engaging portion.

The invention according to claim 3 is the workpiece gripping system according to claim 2 , wherein the transmission shaft is positioned on the rotary drive device side, the screw shaft side, and the drive shaft. And a driven shaft that is coaxially fitted so as to transmit a rotational force, and an elastic body is mounted between the drive shaft and the driven shaft, and the drive shaft and the driven shaft are It is configured to be able to move close to each other in the axial direction against an urging force.

  According to the present invention, when the screw shaft and the transmission shaft cannot be normally engaged, for example, the drive shaft and the driven shaft can move close to each other in the axial direction against the biasing force of the elastic body. Therefore, it is possible to protect the workpiece gripping system by absorbing a load at the time of engagement such as impact.

The invention according to claim 4 is the work gripping system according to claim 3 , wherein the abutting portion moving drive device includes a driven shaft displacement detecting portion that detects axial displacement of the driven shaft; A recognition unit for recognizing that the screw shaft and the transmission shaft are not normally engaged when the displacement of the driven shaft is detected by the driven shaft displacement detector; To do.

  According to the present invention, it can be easily recognized that the screw shaft and the transmission shaft are not normally engaged based on the axial displacement of the driven shaft. Thereby, when the screw shaft and the transmission shaft are not normally engaged, for example, after the screw shaft and the transmission shaft are separated from each other, the engagement between the two is tried again or a warning is given. It is possible to execute error processing.

The invention according to claim 5 is the workpiece holding system according to any one of claims 1 to 4, wherein the abutment moving drive device, the movably supported freely contact A contact part displacement detection part for detecting a displacement of the part, and a control part for controlling the operation of the rotary drive device so that the displacement of the contact part detected by the contact part displacement detection part becomes a target value; It is characterized by having.

  According to the present invention, it is possible to easily control the alignment of the contact portion according to the type of workpiece on the contact portion moving drive device side.

The invention according to claim 6 is the workpiece gripping system according to any one of claims 1 to 5 , wherein the workpiece has a shell portion having a shell shape, and the workpiece The contacted portion is located on an outer surface or an inner surface of the shell portion.

  According to the present invention, the work can be securely held by gripping the outer surface or the inner surface of the shell portion having a shell shape. Therefore, it is composed of a so-called shell structure (shell structure), and as a workpiece gripping system for gripping and transporting a workpiece such as a transmission case or a torque converter case whose shape and size of the shell portion changes according to product variations, It can be particularly preferably used.

  According to the present invention, it is possible to provide a workpiece gripping system that can flexibly handle various workpieces and can securely hold and transport the workpieces with a single lightweight workpiece gripping device attached to the robot arm. .

1 is a schematic plan view showing an overall configuration of a workpiece gripping system according to an embodiment of the present invention. It is a schematic plan view for demonstrating a mode that a workpiece | work is gripped with the workpiece | work holding apparatus shown by FIG. It is a schematic perspective view of the workpiece | work holding apparatus shown by FIG. It is a schematic bottom view of the workpiece | work holding apparatus shown by FIG. It is sectional drawing which follows the VO line of FIG. FIG. 6 is a plan view of FIG. 5. FIG. 6 is a left side view of FIG. 5. FIG. 6 is a schematic perspective view showing the periphery of the arm of the drive mechanism shown in FIG. 5 as viewed obliquely from below. It is sectional drawing which follows the IX-IX line of FIG. It is sectional drawing which follows the OX line | wire of FIG. It is sectional drawing which follows the O-XI line of FIG. FIG. 12 is a bottom view of FIG. 11. It is a right view of FIG. It is a side view which shows a part of drive device for contact | abutting part movement in a cross section. It is a top view of the drive device for contact part movement. (A) is sectional drawing which follows the AA line of FIG. 14, (b) is sectional drawing which follows the BB line of FIG. It is a control block diagram of a workpiece gripping system. It is the schematic perspective view seen from the slanting lower part which shows the arm periphery of the modification of a drive mechanism. It is the figure seen from the arm side of the drive mechanism which concerns on a modification. It is sectional drawing which follows the XX-XX line of FIG. (A) (b) is sectional drawing which shows typically the modification of the attachment structure of a drive mechanism. (A)-(c) is a schematic plan view for demonstrating the variation of the holding | grip method of a workpiece | work.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a schematic plan view showing the overall configuration of a workpiece gripping system according to an embodiment of the present invention. FIG. 2 is a schematic plan view for explaining a state in which a workpiece is gripped by the workpiece gripping apparatus shown in FIG. FIG. 3 is a schematic perspective view of the workpiece gripping apparatus shown in FIG. FIG. 4 is a schematic bottom view of the workpiece gripping apparatus shown in FIG.

  As shown in FIG. 1, the workpiece gripping system is provided with a robot 100 including a robot arm 101, a workpiece gripping device 1 attached to the tip 102 of the robot arm 101, and the workpiece gripping device 1. 1 has a contact part moving drive device 300 for moving the contact parts 11, 12, and 12 (see FIGS. 2 and 3) supported so as to be freely movable.

  The workpiece gripping device 1 can be suitably used as a holding device (robot hand) that is attached to the tip portion 102 of the robot arm 101 of the articulated robot 100 and grips and holds the workpiece W having various variations.

  The articulated robot 100 grips the workpiece W, which has been transported to the take-out position by the transport device 200 such as a roller conveyor, by the workpiece gripping device 1 attached to the tip portion 102 of the robot arm 101, and turns the robot arm 101. It is in charge of the process of transporting the workpiece W to the next process by moving it.

  As shown in FIGS. 1 and 2, the workpiece gripping device 1 is provided on the support plate 2 connected to the robot arm 101 and the support plate 2, and the workpiece W is first contacted when the workpiece W is gripped. A driving-side abutting portion 11 (see also FIG. 5) and receiving-side abutting portions 12, 12 that respectively abut against the portion W1 and the second abutted portions W2, W2, and grip the workpiece W; It has. In addition, the code | symbol "8" in FIG. 2 shows the pressing member 8 mentioned later. Further, the drive-side contact portion 11 and the receiving-side contact portions 12 and 12 are respectively connected to two points in FIG. 2 according to the type of the workpiece W by the free movement mechanisms 5a and 5b (see FIG. It can be moved in the direction of the arrow indicated by the chain line.

  In the present embodiment, the workpiece W is constituted by a so-called shell structure (shell structure), and has a shell portion (rib-like wall portion) S exhibiting a shell shape. Examples of the workpiece W include a transmission case and a torque converter case. Here, the first contacted part W1 and the second contacted parts W2, W2 of the workpiece W are located on the outer surface of the shell part S, respectively.

  As shown in FIGS. 3 and 4, the support plate 2 has a substantially triangular plate shape, and is connected to the distal end portion 102 of the robot arm 101 via a substantially cylindrical mounting portion 21. 4 indicates the center of the support plate 2, that is, the center of the attachment portion 21 to which the distal end portion 102 of the robot arm 101 is coupled. Here, the drive-side contact portion 11 and the receiving-side contact portions 12, 12 are arranged at substantially equal angle (120 degrees) intervals in the circumferential direction around the center O of the support plate 2. However, it does not necessarily have to be equiangular intervals.

  Further, the workpiece gripping device 1 is disposed on the support plate 2, and when the workpiece W is gripped, the driving mechanism 3 that presses the driving-side contact portion 11 against the first contacted portion W <b> 1 of the workpiece W; Movement mechanism 5a, 5b for supporting the abutting portion 11 and the receiving-side abutting portions 12, 12 with respect to the support plate 2 so as to be freely movable, and movement regulation for restricting the free movement by the free movement mechanisms 5a, 5b. Devices 71, 71.

  FIG. 5 is a cross-sectional view taken along line VO in FIG. 6 is a plan view of FIG. FIG. 7 is a left side view of FIG. FIG. 8 is a schematic perspective view showing the periphery of the arm of the drive mechanism shown in FIG. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG.

  As shown in FIGS. 5 to 7, the free movement mechanism 5 a includes support members 51 a and 51 b that are fixed to the support plate 2, a screw shaft 52 that is rotatably supported by the support members 51 a and 51 b, and a screw shaft 52. A nut member 53 that is screwed to the nut member 53, a mounting member 54 a that is fixed to the nut member 53 and is provided with the driving mechanism 3 to which the driving-side contact portion 11 is attached, and the mounting member 54 a to the support plate 2. And a linear motion guide device 55 (see FIG. 6) for guiding the screw shaft 52 so as to be movable in the axial direction. Further, on the end surface of the mounting member 54a opposite to the center O of the support plate 2, an abutting portion displacement detector disposed in the abutting portion moving drive device 300 (see FIGS. 1 and 14, the same applies hereinafter). A detected plate 59 detected by 350 (see FIG. 14) is attached.

  The nut member 53 and the attachment member 54a are fixed by, for example, a screw member 58 (see FIG. 6). In addition, the code | symbol 22 in FIG. 6 shows the escape hole required in the assembly operation | work of the workpiece | work holding device 1. FIG.

  The screw shaft 52 includes a screw shaft side engaging portion 52 a that can be connected to a transmission shaft 301 (see FIG. 14) of the contact portion moving drive device 300 provided outside the workpiece gripping device 1. The screw shaft side engaging portion 52a is engaged with a transmission shaft side engaging portion 304 (see FIG. 14) provided on the transmission shaft 301 of the external abutting portion moving drive device 300 so that rotational force can be transmitted. It is possible to

  The linear motion guide device 55 is provided between the support plate 2 and the mounting member 54a, and the guide rail 56 disposed on the lower surface of the support plate 2 along the axial direction of the screw shaft 52, and the mounting member 54a. And a holder 57 that is movably disposed along the guide rail 56.

  The movement restricting device 71 is installed on the outer edge of the support plate 2 via the mounting plate 23 so that the screw shaft 52 passes through the inside of the movement restricting device 71. The movement restricting device 71 clamps the screw shaft 52 and stops the rotation when restricting the free movement by the free movement mechanism 5a. Here, the movement restricting device 71 is a pneumatic device and operates by air pressure. For example, the movement regulating device 71 opens the clamp portion that clamps the screw shaft 52 against the urging force of a spring member (none of which is shown) by supplying air from the air supply port 71a. The clamp portion is closed by the urging force of the spring member to clamp the screw shaft 52 by stopping the air supply from the air supply port 71a, and a commercially available shaft clamp should be used. Can do. However, the structure of the movement control apparatus 71 is not limited to this.

  According to the configuration as described above, the contact portion moving drive device 300 (see FIG. 14) provided outside the workpiece gripping device 1 is connected to the screw shaft side engaging portion 52a of the screw shaft 52 to operate. Thus, the drive-side contact portion 11 can be moved in the axial direction of the screw shaft 52 by the screw feeding action of the screw shaft 52 and the nut member 53. In addition, by freely clamping the screw shaft 52 and stopping the rotation, the free movement by the free movement mechanism 5a can be easily regulated. In this way, the free movement mechanism 5a and the movement restricting device 71 can have a simple and compact configuration.

  The screw shaft 52 is formed with a trapezoidal screw that is screwed into the nut member 53 and has a trapezoidal cross section. A trapezoidal screw has a smaller apex angle of the thread than a general triangular screw, and the slope of the thread is tight. Therefore, the nut member 53 and the screw shaft 52 can be held by the self-locking effect due to the use of the trapezoidal screw, and for example, an unexpected situation such as dropping of the workpiece W from the workpiece gripping device 1 can be suppressed. Is possible.

  As shown in FIGS. 5, 7, and 8, the drive mechanism 3 is moved in the axial direction by the drive source 31 that generates the drive force, the main body 32 to which the drive source 31 is attached, and the drive force of the drive source 31. A shaft 33 to be moved, and an arm 35 arranged to be swingable around a pin (fulcrum) 34 provided on the main body 32. At the time of gripping the workpiece W, one end side (upper end side) of the arm 35 is pressed leftward in FIG. 5 by the shaft 33 and the other end side (lower end side) pushes the contact portion 11 on the driving side to the workpiece. It is comprised so that it may press toward W. According to such a configuration, the work W can be reliably held by effectively utilizing the space occupied by the drive mechanism 3, and the drive mechanism 3 can be made compact.

  The drive mechanism 3 includes a drive gear 36 that is rotated by the driving force of the drive source 31 and a nut portion 37 that is fixed to the main body portion 32. A driven gear 38 that meshes with the drive gear 36 is fixed to the shaft 33, and an external thread 39 that engages with the nut portion 37 is formed on the outer peripheral surface of the shaft 33.

  According to such a configuration, the drive gear 36 is rotated by the driving force of the drive source 31 and the driven gear 38 fixed to the shaft 33 is rotated, whereby the shaft 33 and the nut portion 37 in which the male screw 39 is formed. The shaft 33 can be moved in the axial direction by the screw feeding action. In this way, the drive mechanism 3 can have a simple and more compact configuration.

  The main body portion 32 includes a housing 32a in which the drive gear 36, the driven gear 38, and the nut portion 37 are disposed, and a cover 32b that is attached to the opening end side of the housing 32a. A pair of support plate portions 32c for supporting the pins 34 are formed on the arm 35 side of the housing 32a. The drive source 31 and the movement restriction device 72 are attached to the cover 32b by, for example, screw fastening.

  Here, the drive source 31 is a pneumatic device and operates by air pressure. For example, the drive source 31 rotates the drive gear 36 by a predetermined angle (for example, 180 degrees) clockwise by supplying air from the air supply port 31a, while the drive gear 36 is supplied by supplying air from the air supply port 31b. Is rotated counterclockwise by a predetermined angle (for example, 180 degrees), and a commercially available rotary actuator can be used. However, the configuration of the drive source 31 is not limited to this.

  The movement restricting device 72 is installed such that the shaft 33 passes through the inside of the movement restricting device 72. The movement restricting device 72 is used to clamp the shaft 33 to stop the rotation and maintain the unclamped state of the workpiece W when the drive-side contact portion 11 is separated from the workpiece W. Here, the movement restricting device 72 is a pneumatic device and operates by air pressure. As the movement restricting device 72, for example, one having the same structure as that of the movement restricting device 71 described above can be used, but the configuration of the movement restricting device 72 is not limited to this.

  The external thread 39 formed on the shaft 33 is a trapezoidal screw that is screwed into the nut portion 37 and has a trapezoidal cross section. Accordingly, the nut portion 37 and the shaft 33 can be held by the self-locking effect due to the use of the trapezoidal screw, and for example, an unexpected situation such as dropping of the workpiece W from the workpiece gripping device 1 can be suppressed. It becomes possible.

  Here, the contact portion 11 on the driving side has a cylindrical shape, and the contact surface with the workpiece W is made of resin. Thereby, the workpiece W can be gripped without being damaged. Specifically, the contact portion 11 has an outer layer 11a formed from a resin and an inner layer 11b formed from a metal disposed inside the outer layer 11a (see FIG. 7). By forming only the outer layer 11a from the resin in this way, it is possible to suppress the possibility of deformation or cracks occurring in the resin member due to, for example, an impact during gripping. Examples of the material of the outer layer 11a of the contact portion 11 include polyacetal resin (POM), polyamide resin (PA), tetrafluoroethylene resin (PTFE), and the like. However, the contact portion 11 may be formed of another material having a hardness lower than that of the workpiece W.

  The drive-side contact portion 11 is fixed to the lower end of the arm 35 by a screw member 42 with a cylindrical collar 41 interposed therebetween, and is attachable to and detachable from the workpiece gripping device 1. Therefore, the abutting portion 11 is in frequent contact with the workpiece W, but can be easily replaced when there is damage or there is a possibility that the workpiece W can be held more reliably.

  As shown in FIGS. 5 and 9, the drive mechanism 3 has a connection mechanism 43 that connects the tip end side of the shaft 33 and the upper end side of the arm 35. The coupling mechanism 43 includes an annular groove 43a formed in the circumferential direction on the outer peripheral surface on the distal end side of the shaft 33, and a pin 43b provided on the upper end side of the arm 35 and engaged with the groove 43a. Have. The coupling mechanism 43 is disposed in a circular recess 44 formed on the upper end side of the arm 35, and the pin 43 b is provided so as to protrude radially inward from the inner surface of the recess 44.

  According to such a configuration, the distal end side of the shaft 33 and the upper end side of the arm 35 can be coupled by the coupling mechanism 43 having a simple configuration with a small number of parts. Then, by moving the shaft 33 to the opposite side of the arm 35, the arm 35 is swung via the connecting mechanism 43, and the contact portion 11 on the drive side of the workpiece gripping device 1 is moved to the contact portion W1 of the workpiece W. The state can be maintained by being separated from the head.

  Further, on the bottom surface of the recess 44, for example, a disk-shaped pressed member 45 is installed by press fitting or the like. Therefore, by moving the shaft 33 toward the arm 35, the pressed member 45 is pressed by the tip of the shaft 33 to swing the arm 35, and the contact portion 11 on the driving side of the workpiece gripping device 1 is moved to the workpiece W. The contacted portion W1 can be pressed. The pressed member 45 is made of, for example, a steel plate having good wear resistance and high strength, and wear and damage can be suppressed even by frequent pressing by the tip of the shaft 33.

10 is a cross-sectional view taken along the line XX of FIG.
As shown in FIG. 10, the workpiece gripping device 1 also includes a pressing member 8 that is disposed on the support plate 2 via a support column 83. The holding member 8 comes into contact with the end surface of the workpiece W on the support plate 2 side when the workpiece W is gripped. According to such a configuration, the workpiece W can be pressed by the pressing member 8 when the workpiece W is gripped by pressing the drive-side contact portion 11 against the contacted portion W1 (see FIG. 2) of the workpiece W. It is possible to prevent the workpiece W from being inclined with respect to the workpiece gripping device 1. As a result, it is possible to avoid a situation in which the gripping posture of the workpiece W is changed and the work at the transfer destination of the workpiece W is hindered.

  The support column 83 includes a long plate member 84 that extends in a direction perpendicular to the plane of the support plate 2, and a mounting plate 85 that is fixed to the support plate 2 side of the plate member 84. The mounting plate 85 is fixed to the support plate 2 by screw fastening or the like, and the pressing member 8 is fixed to the end portion of the plate member 84 opposite to the support plate 2 by screw fastening or the like.

  The pressing member 8 is long and extends from the center O of the support plate 2 (see FIG. 4) along a direction outward in the radial direction. Accordingly, the work W can be pressed by the pressing member 8 in a flexible manner corresponding to various works W having different sizes and shapes. Further, the pressing member 8 is disposed on the opposite side of the driving-side contact portion 11 and the receiving-side contact portions 12 and 12 (see FIG. 2) with respect to the center O of the support plate 2. Specifically, the pressing member 8 is substantially equiangular (120 degrees) in the circumferential direction around the center O of the support plate 2, and has a contact portion 11 on the driving side and a contact portion 12 on the receiving side, 12 between the contact portions. Therefore, when gripping the workpiece W, the opposite side of the workpiece W against the contact portion W1, W2, W2 (see FIG. 2) with respect to the center O of the support plate 2 can be pressed by the pressing member 8, respectively. It becomes possible to more effectively suppress the change in the gripping posture of W. When the pressing member 8 is arranged, the abutting portions are set not to be opposite to each other with respect to the center O of the support plate 2.

  The pressing member 8 includes a contact portion 81 positioned on the workpiece W side and an attachment portion 82 positioned on the opposite side of the workpiece W. Here, the contact portion 81 is made of resin. Thereby, it is possible to hold the workpiece W without damaging it. As resin used as the material of the contact part 81, the thing similar to the contact part 11 is mentioned, for example. However, the contact portion 81 may be formed of another material having a lower hardness than the workpiece W. The contact portion 81 is fixed to the lower surface of the attachment portion 82 by, for example, screw fastening, and is attachable to and detachable from the workpiece gripping device 1. Therefore, the contact portion 81 can be easily replaced when there is damage or there is a possibility of the damage, and the work W can be held more reliably.

FIG. 11 is a cross-sectional view taken along the line O-XI in FIG. FIG. 12 is a bottom view of FIG. FIG. 13 is a right side view of FIG.
As shown in FIGS. 11 to 13, the free movement mechanism 5 b includes support members 51 a and 51 b that are fixed to the support plate 2, a screw shaft 52 that is rotatably supported by the support members 51 a and 51 b, and a screw shaft 52. A nut member 53 that is screwed to the nut member 53, an attachment member 54 b that is fixed to the nut member 53 and provided with the receiving side contact portion 12, and an axial direction of the screw shaft 52 with respect to the support plate 2. And a linear motion guide device 55 for movably guiding it. Further, on the end surface of the mounting member 54 b opposite to the center O of the support plate 2, the object detected by the contact part displacement detection unit 350 (see FIG. 14) disposed in the contact part movement drive device 300. A detection plate 60 is attached.

  Although the size and shape of the attachment member 54b are different from the attachment member 54a in the free movement mechanism 5b, since the other structure is the same as that of the free movement mechanism 5a shown in FIGS. 5-7, detailed description is abbreviate | omitted. . Moreover, since the movement control apparatus 71 shown in FIGS. 11-13 is the same as that shown in FIGS. 5-7, detailed description is abbreviate | omitted.

  The contact portion 12 on the receiving side is disposed on the attachment member 54 b via the support member 61. The column member 61 has a long cylindrical portion 62 that extends in a direction perpendicular to the plane of the mounting member 54 b, and a plate-like portion 63 that is fixed to the mounting member 54 b side of the cylindrical portion 62. The plate-like portion 63 is fixed to the attachment member 54b by screw fastening or the like. The receiving-side contact portion 12 is fixed to the end portion of the columnar portion 62 opposite to the mounting member 54b by a screw member 42 with a cylindrical collar 41 interposed therebetween. Can be removed. Therefore, the contact portion 12 can be easily replaced when there is damage or there is a risk of the damage, and the work W can be held more reliably. Here, the receiving-side contact portion 12 has the same configuration as the drive-side contact portion 11, and thus detailed description thereof is omitted.

Next, the contact part moving drive device 300 will be described.
FIG. 14 is a side view showing a part of the abutting portion moving drive device in section. FIG. 15 is a plan view of the abutting portion moving drive device. 16A is a cross-sectional view taken along line AA in FIG. 14, and FIG. 16B is a cross-sectional view taken along line BB in FIG.

  As shown in FIG. 14, the contact portion moving drive device 300 includes a motor 305 as a rotational drive device, and a screw shaft of the freely moving mechanisms 5 a and 5 b (see FIGS. 5 and 11). 52 and a transmission shaft 301 that transmits to 52. Further, as described above, the transmission shaft 301 has the transmission shaft side engaging portion 304 provided at the end on the screw shaft 52 side, and the screw shaft 52 engages with the transmission shaft side engaging portion 304. It has a possible screw shaft side engaging portion 52a.

  As shown in FIG. 16A, here, the cross section perpendicular to the transmission shaft 301 side end of the screw shaft side engaging portion 52a is a regular hexagonal shaft, and the transmission shaft side engaging portion 304 The axially perpendicular cross section of the screw shaft 52 side end portion presents a substantially hexagonal star-shaped hole as a whole in which the end portion of the screw shaft side engaging portion 52a is inscribed and fitted. However, the screw shaft side engaging portion 52a and the transmission shaft side engaging portion 304 may have other axis-perpendicular cross-sectional shapes such as a square as long as the screw shaft side engaging portion 304 is coaxially fitted so as to transmit the rotational force. Thus, it is preferable to adopt a configuration in which the screw shaft side engaging portion 52a and the transmission shaft side engaging portion 304 are fitted coaxially so that rotational force can be transmitted, since the number of components is small and the configuration is simplified. Alternatively, the screw shaft side engaging portion 52a may be configured such that the axially perpendicular cross section exhibits a hole, and the transmission shaft side engaging portion 304 has an axially perpendicular cross section. Furthermore, the screw shaft side engaging portion 52a and the transmission shaft side engaging portion 304 can adopt any form as long as the rotational force is engaged so that the rotational force can be transmitted. For example, the rotational force is transmitted by a gear. It may be.

  As shown in FIG. 14, the transmission shaft 301 is a drive shaft 302 positioned on the motor 305 side and a driven shaft that is positioned on the screw shaft 52 side and is coaxially fitted to the drive shaft 302 so as to be able to transmit rotational force. 303. The transmission shaft side engaging portion 304 is coupled to the end of the driven shaft 303 on the screw shaft 52 side so as to be able to transmit a rotational force by, for example, a key (not shown) and a set screw (not shown). Etc., and is attachable to and detachable from the driven shaft 303.

  The contact portion moving drive device 300 includes a support body 306 installed on the floor, and the motor 305 is attached to a bracket 307 fixed to the support body 306. The drive shaft 302 is rotatably supported by a bearing member 309 installed in a holder 308 fixed to the support body 306, and the driven shaft 303 is installed in a holder 310 fixed to the support body 306. The bearing bush 311 is rotatably supported. The end of the drive shaft 302 on the motor 305 side is connected to the output shaft 305 a of the motor 305 via a coupling 312.

  As shown in FIG. 16B, here, the cross section perpendicular to the driven shaft 303 side of the drive shaft 302 has a square axis, and the end of the driven shaft 303 on the drive shaft 302 side. A cross section perpendicular to the axis of 303a presents a substantially square hole as a whole into which the end 302a of the drive shaft 302 is inscribed and fitted. However, the end portion 302a of the drive shaft 302 and the end portion 303a of the driven shaft 303 may have another axially perpendicular cross-sectional shape such as a hexagon as long as the rotational force can be transmitted coaxially. Further, the cross section perpendicular to the axis of the end 302a of the drive shaft 302 may be a hole, and the cross section perpendicular to the axis of the end 303a of the driven shaft 303 may be an axis.

  As shown in FIG. 14, a compression coil spring 313 as an elastic body is mounted between the drive shaft 302 and the driven shaft 303, and the drive shaft 302 and the driven shaft 303 are biased by the compression coil spring 313. It is configured to be able to move close to each other in the axial direction against this. An escape hole 314 is formed inside the driven shaft 303 to prevent the drive shaft 302 and the driven shaft 303 from interfering with each other in the axial direction when the drive shaft 302 and the driven shaft 303 move close to each other. In a normal state, the flange portion 303 b provided on the outer peripheral surface of the end portion 303 a of the driven shaft 303 is urged by the compression coil spring 313 and is in contact with the end surface of the holder 310.

  As shown in FIGS. 14 and 15, the contact part moving drive device 300 includes a driven shaft displacement detector 320 that detects the displacement of the driven shaft 303 in the axial direction. The driven shaft displacement detection unit 320 is supported by a linear bushing 322 attached to a bracket 321 fixed to the support body 306 so as to be slidable in the axial direction, and confirmed to move in the axial direction in conjunction with the driven shaft 303. A shaft 323, a detected element 324 provided on the movement confirmation shaft 323, and a sensor 325 for detecting the detected element 324 are provided. A connection member 326 is fixed to one end of the movement confirmation shaft 323, and this connection member 326 is rotatable relative to the driven shaft 303 by a bearing member 327 and axially by a retaining ring member 328. It is connected so that movement is restricted.

  The detected element 324 includes a disk-shaped first detected element 324 a and a second detected element 324 b that are installed on the movement confirmation shaft 323 in the axial direction. In addition, the sensor 325 is used when the first sensor 325a that detects the first detected element 324a and the screw shaft 52 and the transmission shaft 301 cannot be normally engaged when the compression coil spring 313 has the maximum operating length. And a second sensor 325b that detects the second detected element 324b when the driven shaft 303 is pressed toward the drive shaft 302 and the compression coil spring 313 becomes shorter than the maximum operating length by a predetermined value. In addition, the 1st sensor 325a and the 2nd sensor 325b are attached to the bracket 329 fixed to the support body 306, for example, a proximity sensor is used.

  Further, the contact portion moving drive device 300 detects the displacement of the contact portions 11, 12, and 12 (see FIGS. 5 and 11) supported so as to be freely movable with respect to the support plate 2. A detection unit 350 is included. The contact portion displacement detection unit 350 is attached to a bracket 353 fixed to the support body 306. The contact portion displacement detection unit 350 includes a rod 351 that can move in an axial direction parallel to the transmission shaft 301, and a cylinder portion 352 that moves the rod 351 by, for example, air pressure, and uses, for example, a magnetoresistive element. Thus, the movement stroke of the rod 351 can be output as a signal. The tip portion 351a of the rod 351 moves following the movement of the detection plates 59 and 60 by being pressed against the detection plates 59 and 60 by the air pressure of the cylinder portion 352. As a result, the displacement of the detected plates 59 and 60, and hence the displacement of the contact portions 11 and 12 (see FIGS. 5 and 11), can be detected as the movement stroke signal of the rod 351. As the contact portion displacement detection unit 350, a commercially available measurement cylinder (Monosakuin (registered trademark)) manufactured by SMC, for example, can be used. However, the contact portion displacement detection unit 350 is not limited to the above-described configuration.

FIG. 17 is a control block diagram of the workpiece gripping system.
As shown in FIG. 17, the control device 500 that controls the entire workpiece gripping system controls the operation of the robot controller 501 that controls the operation of the robot 100 (see FIG. 1) and the drive source 31 of the workpiece gripping device 1. And a contact part movement control unit 503 for controlling the operation of the motor 305 of the contact part movement drive device 300 (see FIG. 14). Here, the robot control unit 501, the workpiece gripping control unit 502, and the contact unit movement control unit 503 can communicate with each other. However, a configuration in which one processing device fulfills the functions of these control units may be employed. The robot control unit 501 is connected to the imaging device 504. For example, when the workpiece W is gripped, the robot control unit 501 receives image information obtained by imaging the workpiece W at the workpiece W take-out position from the imaging device 504.

  The contact part movement control unit 503 is connected to the driven shaft displacement detection unit 320 and the contact part displacement detection unit 350, respectively. The contact portion movement control unit 503 receives a signal from the driven shaft displacement detection unit 320 as to whether or not the screw shaft 52 and the transmission shaft 301 have been normally engaged. The contact portion movement control unit 503 recognizes that the screw shaft 52 and the transmission shaft 301 are not normally engaged when the driven shaft displacement detection unit 320 detects a displacement greater than a predetermined value of the driven shaft 303. To do. Further, the contact portion movement control unit 503 changes the contact portion 11, 12 when the type of the workpiece W is changed and the contact portions 11, 12, 12 (see FIGS. 5 and 11) need to be moved. , 12 are received from the contact part displacement detector 350. The contact part movement control unit 503 controls the operation of the motor 305 so that the displacement of the contact parts 11, 12, and 12 detected by the contact part displacement detection unit 350 becomes a target value.

Next, the operation of the workpiece gripping system according to this embodiment will be described.
As shown in FIG. 1, the workpiece W is transported by the transport device 200 and stopped at the take-out position. Here, it is assumed that the imaging apparatus 504 (see FIG. 17) is mounted on the workpiece gripping apparatus 1. Then, in a state where the workpiece W is stopped at the take-out position, the robot 100 moves the workpiece gripping device 1 on which the imaging device 504 is mounted to the imaging position of the workpiece W according to a command from the robot control unit 501 (see FIG. 17). The workpiece W is moved, the workpiece W is imaged by the imaging device 504, and the posture and position of the workpiece W placed on the transport device 200 are detected from the obtained image information.

  Subsequently, based on the obtained image information, the robot 100 changes the posture and position of the workpiece gripping device 1 according to a command from the robot control unit 501, thereby causing the workpiece gripping device 1 to face the workpiece W. At this time, the drive-side contact portion 11 is in a position facing the first contacted portion W1 (see FIG. 2) of the workpiece W with a slight gap in the horizontal direction. Further, the two receiving-side contact portions 12 and 12 have a slight gap in the horizontal direction and face the two second contacted portions W2 and W2 (see FIG. 2) of the workpiece W, respectively. In position.

  Then, the drive source 31 of the drive mechanism 3 is actuated by a command from the workpiece gripping control unit 502 (see FIG. 17), whereby the shaft 33 is moved in the axial direction and presses the upper end side of the arm 35. 35 is swung counterclockwise in FIG. Accordingly, the drive-side contact portion 11 provided on the lower end side of the arm 35 presses the first contacted portion W1 of the workpiece W. As a result, the drive-side contact portion 11 and the receiving-side contact portions 12 and 12 are connected to the first contacted portion W1 and the second contacted portions W2 and W2 located on the outer surface of the workpiece W, respectively. The workpiece W is gripped in contact with the three directions. At this time, the pressing member 8 also comes into contact with the end surface of the workpiece W on the support plate 2 side.

  Subsequently, in response to a command from the robot controller 501, the robot 100 turns and moves the robot arm 101 while holding the workpiece W with the workpiece gripping device 1, and transports it to the next process. By releasing the gripping state by the command, the workpiece W is transferred to the next process. By repeating such an operation, the robot 100 uses the workpiece gripping device 1 to grip and transport a plurality of workpieces W.

Next, an operation for moving the contact portions 11, 12, and 12 according to the type of the workpiece W will be described.
When the contact portions 11, 12, and 12 are moved in response to a change in the type of the workpiece W, the robot 100 causes the workpiece gripping device 1 to move the contact portion moving drive device 300 (see FIG. 14), the screw shaft side engaging portion 52a of the screw shaft 52 is engaged with the transmission shaft side engaging portion 304 of the transmission shaft 301. At this time, if the screw shaft 52 and the transmission shaft 301 are normally engaged, the screw shaft side engaging portion 52a is fitted to the transmission shaft side engaging portion 304, and the driven shaft 303 moves in the axial direction. Therefore, a signal indicating that the first sensor 325a for detecting the first detected element 324a is on and the second sensor 325b is off is output from the driven shaft displacement detector 320 to the contact part movement controller 503.

  As shown in FIG. 14, when the screw shaft 52 and the transmission shaft 301 are normally engaged, the contact part movement control unit 503 (see FIG. 17) is detected by the contact part displacement detection unit 350. The motor 305 is rotationally driven so that the displacement of the contact portions 11 and 12 becomes a target value set in advance according to the type of the workpiece W.

  On the other hand, when the screw shaft 52 and the transmission shaft 301 are not normally engaged, the end surface of the screw shaft side engaging portion 52a abuts on the end surface of the transmission shaft side engaging portion 304, and the driven shaft 303 is driven. A signal indicating that the compression coil spring 313 is pressed by the shaft 302 side is shorter than the maximum operating length by a predetermined value, the first sensor 325a is turned off, and the second sensor 325b that detects the second detected element 324b is turned on is driven. The shaft displacement detection unit 320 outputs the contact part movement control unit 503. When receiving the signal, the contact part movement control unit 503 recognizes that the screw shaft 52 and the transmission shaft 301 are not normally engaged. In this case, the contact part movement control unit 503 executes predetermined error processing. For example, the contact part movement control unit 503 notifies the robot control unit 501 (see FIG. 17), and after the robot 100 once separates the workpiece gripping device 1 from the contact part movement drive device 300, Control to engage the screw shaft 52 with the transmission shaft 301 is performed. In addition, the contact part movement control unit 503 may execute control for issuing warnings such as generation of an alarm sound, blinking of a warning light, display of an error message, and the like.

  As described above, the workpiece gripping system according to the present embodiment is disposed on the support plate 2 and the support plate 2 connected to the robot arm 101, and when the workpiece W is gripped, the plurality of contacted portions W1, W2 of the workpiece W are arranged. , W2 and a plurality of abutting portions 11, 12, 12 for holding the workpiece W, and the support plate 2, and driving of the plurality of abutting portions 11, 12, 12 when the workpiece W is gripped. Drive mechanism 3 having a drive source 31 that generates a driving force for pressing the contact portion 11 on the side against the workpiece W, and supports the plurality of contact portions 11, 12, 12 movably with respect to the support plate 2. The workpiece gripping device 1 provided with the freely moving mechanisms 5a and 5b and the movement restricting devices 71 and 71 for restricting the free movement by the freely moving mechanisms 5a and 5b, and provided outside the workpiece gripping device 1 and freely movable. Has a contact portion moving drive unit 300, a moving contact portion 11,12,12 which are supported.

Therefore, according to this embodiment, since the plurality of contact portions 11, 12, 12 can be freely moved by the free movement mechanisms 5a, 5b, the contact portions 11, 12, 12 of the workpiece gripping device 1 are previously set. By aligning the workpieces W in correspondence with the contacted portions W1, W2, and W2, and holding the positions by the movement restricting devices 71 and 71, the workpiece W can be flexibly applied to various workpieces having different shapes and sizes. It can correspond to.
Then, the alignment of the contact portions 11, 12, 12 can be realized by using the contact portion moving drive device 300 provided outside the workpiece gripping device 1. For this reason, in the workpiece gripping system according to the present embodiment, the driving unit 300 for moving the abutting portion that aligns the abutting portions 11, 12, and 12 is not provided in the workpiece gripping device 1 and is provided outside as a separate body. Thus, it is possible to deal with various workpieces W having variations while realizing weight reduction of the workpiece gripping device 1.
That is, it is possible to provide a workpiece gripping system that can flexibly handle various workpieces W with the single workpiece gripping device 1 reduced in weight attached to the robot arm 101 and can securely hold and transport the workpieces W. .

  In addition, when the workpiece W is gripped, a plurality of abutting portions 11, 12, and 12 for gripping the workpiece W by respectively abutting against the plurality of abutted portions W 1, W 2, and W 2 of the workpiece W are provided. Since the driving-side contact portion 11 of the plurality of contact portions 11, 12, and 12 is pressed against the first contacted portion W1 of the workpiece W by force, the outer surface or the inner surface of the workpiece W is gripped. can do. Thereby, even if the workpiece gripping device 1 is not accurately positioned with respect to the workpiece W, the workpiece W can be gripped. Therefore, in the manufacturing process, the work time can be shortened, and the occurrence of work mistakes in which the workpiece W cannot be gripped can be suppressed. Further, the workpiece W can be reliably and easily gripped regardless of the size and weight of the workpiece W. Furthermore, even if the shape of the workpiece W is complicated, it is easy to secure a place where the contact portions 11, 12, 12 of the workpiece gripping device 1 come into contact with the outer surface or the inner surface of the workpiece W and grip the workpiece W. And excellent in versatility.

  In the present embodiment, the free movement mechanisms 5a and 5b include a nut member 53 in which the contact portions 11, 12, and 12 are disposed, and a screw shaft 52 that is screwed into the nut member 53. The contact moving drive device 300 includes a motor 305 and a transmission shaft 301 that transmits the rotational force of the motor 305 to the screw shaft 52. According to such a configuration, by transmitting the rotational force of the motor 305 to the screw shaft 52 via the transmission shaft 301, the contact portions 11, 12, 12 can be moved in the axial direction of the screw shaft 52, and the free movement mechanisms 5a and 5b can be configured to be simple and compact.

  In this embodiment, the transmission shaft 301 has a transmission shaft side engaging portion 304 provided at an end portion on the screw shaft 52 side, and the screw shaft 52 can be engaged with the transmission shaft side engaging portion 304. It has a screw shaft side engaging portion 52a. According to such a configuration, the rotational force of the motor 305 can be transmitted to the screw shaft 52 with a simple operation of engaging the screw shaft side engaging portion 52 a with the transmission shaft side engaging portion 304.

  In this embodiment, the transmission shaft 301 is a drive shaft 302 positioned on the motor 305 side and a driven shaft that is positioned on the screw shaft 52 side and is coaxially fitted to the drive shaft 302 so as to transmit rotational force. 303, and a compression coil spring 313 is mounted between the drive shaft 302 and the driven shaft 303, and the drive shaft 302 and the driven shaft 303 are mutually in the axial direction against the urging force of the compression coil spring 313. It is configured to be able to move close together. According to such a configuration, when the screw shaft 52 and the transmission shaft 301 cannot be normally engaged, for example, the drive shaft 302 and the driven shaft 303 resist the urging force of the compression coil spring 313. Since they can move close to each other in the axial direction, it is possible to protect the work gripping system by absorbing the load during engagement such as impact.

  In the present embodiment, the abutting portion moving drive device 300 includes a driven shaft displacement detection unit 320 that detects the displacement of the driven shaft 303 in the axial direction, and a driven shaft displacement detection unit 320 that exceeds the predetermined value of the driven shaft 303. A contact portion movement control unit (recognition unit) 503 for recognizing that the screw shaft 52 and the transmission shaft 301 are not normally engaged when the displacement is detected. According to such a configuration, it can be easily recognized that the screw shaft 52 and the transmission shaft 301 are not normally engaged based on the axial displacement of the driven shaft 303. Thereby, when the screw shaft 52 and the transmission shaft 301 are not normally engaged, for example, after the screw shaft 52 and the transmission shaft 301 are separated from each other, the engagement between them is tried again or a warning is given. It is possible to execute error processing such as.

  Further, in the present embodiment, the contact part movement drive device 300 includes a contact part displacement detection part 350 that detects the displacement of the contact parts 11, 12, and 12 supported so as to be freely movable, and a contact part displacement. It has a contact part movement control part (control part) 503 for controlling the operation of the motor 305 so that the displacement of the contact parts 11, 12, and 12 detected by the detection part 350 becomes a target value. According to such a configuration, it is possible to easily perform the alignment control of the contact portions 11, 12, and 12 according to the type of the workpiece W on the contact portion moving drive device 300 side.

  Next, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration (modified example). About the same structure as embodiment mentioned above, the same code | symbol is attached | subjected, the overlapping description is abbreviate | omitted suitably, and a different point is mainly demonstrated.

FIG. 18 is a schematic perspective view of the periphery of the arm of a modified example of the drive mechanism as seen from obliquely below. FIG. 19 is a view as seen from the arm side of the drive mechanism according to the modification. 20 is a cross-sectional view taken along line XX-XX in FIG.
As shown in FIGS. 18 to 20, the drive mechanism 3 a is provided with a drive-side contact portion 11, a pressing member 46 that is pressed by the lower end side of the arm 35 a when gripping the workpiece W, and when the workpiece W is gripped. And a guide mechanism 47 for guiding the pressing member 46 so as to move in a linear direction toward the workpiece W.

  The pressing member 46 includes an engaging portion 46a having a rectangular frame shape that engages so as to surround the lower end portion 35b of the arm 35a, and a moving piece 46b on which the engaging portion 46a is provided on the lower surface. The drive-side contact portion 11 is fixed to the lower surface of the moving piece 46b by a screw member 42. The guide mechanism 47 is positioned inside the pair of groove portions 47a and 47a formed on the side end surface of the moving piece 46b and the pair of rail members 48 and 48 fixed to the main body portion 32, and is located in the groove portions 47a and 47a. And a pair of side end edges 47b and 47b that are slidably fitted to each other. In this way, the pressing member 46 is slidably supported between the pair of rail members 48, 48 and is movable along the axial direction of the shaft 33.

  According to such a configuration, when the shaft 33 presses the upper end side of the arm 35a, the arm 35a swings, the lower end portion 35b of the arm 35a presses the pressing member 46, and the drive-side contact portion 11 The installed pressing member 46 is guided by the guide mechanism 47 and moves in a linear direction toward the workpiece W. Thereby, the contact portion 11 on the drive side of the workpiece gripping device 1 can be pressed in a substantially vertical linear direction with respect to the contacted portion W1 of the workpiece W, and the workpiece W can be held more reliably. .

FIGS. 21A and 21B are cross-sectional views schematically showing modifications of the drive mechanism mounting structure. In FIG. 21, each part is drawn with appropriate enlargement, reduction, simplification, and the like.
In the modification shown in FIG. 21, a connecting member 24 that connects the support plate 2 and the drive mechanism 3 is provided between the support plate 2 and the drive mechanism 3. The support members 51 a and 51 b are fixed to the connection member 24 by the screw member 25, and the connection member 24 is fixed to the support plate 2 by the screw member 26. That is, the support members 51 a and 51 b are fixed to the support plate 2 via the connecting member 24. Although not shown in FIG. 21, the guide rail 56 (see FIG. 7) is fixed to the lower surface of the connecting member 24. That is, the guide rail 56 is disposed on the support plate 2 along the axial direction of the screw shaft 52 via the connecting member 24.

  And the installation direction in the plane parallel to this support plate 2 with respect to the support plate 2 of the connection member 24 is comprised so that change is possible when the connection member 24 rotates a predetermined angle within the said plane. According to such a configuration, when the driving-side contact portion 11 is pressed against the first contacted portion W1 of the workpiece W, the pressing direction of the driving-side contact portion 11 is set to the center of the workpiece W. It can be set in various directions such as a direction approaching (see FIG. 21A) and a direction away from the center of the workpiece W (see FIG. 21B). Therefore, the pressing direction can be adjusted according to the type of the workpiece W, and the workpiece W can be held more reliably.

  Specifically, here, the screw members 26 are disposed at four positions corresponding to the apexes of a quadrangle in a plane parallel to the support plate 2. Therefore, if the screw member 26 is removed and the connecting member 24 is rotated 180 degrees in a plane parallel to the support plate 2 and then the connecting member 24 is fixed to the support plate 2 again by the screw member 26, the contact on the driving side is achieved. The pressing direction of the part 11 can be changed to the opposite direction by 180 degrees. Thereby, the contact part 11 on the driving side can be pressed against both the outer surface and the inner surface of the workpiece W by the single workpiece gripping device 1, and both the outer surface and the inner surface of the workpiece W can be gripped. It becomes possible. Note that the screw members 26 may be arranged at a plurality of locations at equal angular intervals on the circumference in a plane parallel to the support plate 2. In this way, it becomes possible to change the pressing direction of the contact portion 11 on the driving side by an integral multiple of the angular interval between the adjacent screw members 26.

  Here, the main body 32 of the drive mechanism 3 is configured to be fixed to the mounting member 54a by the screw members 27 disposed at four positions corresponding to the vertices of a quadrangle in a plane parallel to the mounting member 54a. (See FIG. 21). For this reason, if the screw member 27 is removed and the drive mechanism 3 is rotated 180 degrees in a plane parallel to the mounting member 54a and then the drive mechanism 3 is fixed again to the mounting member 54a with the screw member 27, the driving side It is possible to change the pressing direction of the contact portion 11 to the opposite direction by 180 degrees. In this case, the attachment member 54 a functions as the connecting member 24 that is disposed between the support plate 2 and the drive mechanism 3 and connects the support plate 2 and the drive mechanism 3. In addition, the screw member 27 may be arrange | positioned in multiple places at equal angular intervals on the circumference in the plane parallel to the attachment member 54a.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the structure described in the said embodiment (a modification is included), The above-mentioned structure is combined thru | or selected suitably. In the range which does not deviate from the meaning, the structure can be changed suitably.

For example, in FIG. 2, the workpiece gripping apparatus 1 grips the workpiece W by bringing the driving-side abutting portion 11 and the receiving-side abutting portions 12 and 12 into contact with the outer surface of the shell portion S of the workpiece W, respectively. Although described, the present invention is not limited to this.
22A to 22C are schematic plan views for explaining variations of the workpiece gripping method. In addition, the arrow in FIG. 22 shows the pressing direction to the workpiece | work W by the contact part 11 by the side of a drive.

  As shown in FIG. 22 (a), the workpiece gripping device 1 has a contact portion 11 on the driving side and a contact portion 12 on the receiving side on the outer surface of a workpiece W having a shell structure, for example, which has a solid cylindrical shape. , 12 may be used to hold the workpiece W by contacting each other. Further, as shown in FIG. 22B, the workpiece gripping device 1 causes the contact portion 11 on the driving side and the contact portions 12 and 12 on the receiving side to contact the inner surface of the shell portion S of the workpiece W, respectively. It may be used to grip the workpiece W. In this case, for example, the drive mechanism 3 in FIG. 5 may be fixed at a position rotated 180 degrees in a plane parallel to the attachment member 54a. Further, as shown in FIG. 22C, the workpiece gripping device 1 causes the driving-side abutting portion 11 to abut on the outer surface of the shell portion S of the workpiece W and is received on the inner surface of the shell portion S of the workpiece W. The side abutting portions 12 and 12 may be brought into contact with each other to be used for gripping the workpiece W.

  In the above-described embodiment, the workpiece gripping apparatus 1 causes the three contact portions, that is, the one contact portion 11 on the driving side and the two contact portions 12 and 12 on the receiving side to contact the workpiece W. However, the present invention is not limited to this. The workpiece gripping device 1 may be configured to grip two workpieces in contact with the workpiece W, or may be configured to grip four workpieces or more in contact with the workpiece W. May be. Further, at least one of the plurality of contact portions may be the drive-side contact portion 11, and for example, all of the contact portions may be the drive-side contact portions 11. Further, in the above-described embodiment, all of the three abutting portions 11, 12, and 12 are supported by the freely moving mechanisms 5a and 5b so as to be freely movable with respect to the support plate 2. However, the present invention is not limited to this. It is not a thing. The present invention may be configured such that at least one of the plurality of abutting portions is supported by the freely moving mechanism so as to be freely movable with respect to the support plate 2.

DESCRIPTION OF SYMBOLS 1 Work gripping device 2 Support plate 3, 3a Drive mechanism 5a, 5b Free movement mechanism 11 Contact part on the drive side 12 Contact part on the receiving side 31 Drive source 52 Screw shaft 52a Screw shaft side engagement part 53 Nut member 71 Movement Restriction device 100 Robot 101 Robot arm 300 Contact unit moving drive device 301 Transmission shaft 302 Drive shaft 303 Driven shaft 304 Transmission shaft side engaging portion 305 Motor (rotary drive device)
320 Driven shaft displacement detector 350 Contact portion displacement detector 500 Controller 503 Contact portion movement controller (recognition unit, controller)
S shell part W work W1 contacted part W1, W2, W2 contacted part

Claims (6)

A support plate connected to the robot arm,
A plurality of abutting portions disposed on the support plate and gripping the workpiece by abutting the plurality of abutted portions of the workpiece when gripping the workpiece;
A drive mechanism that is disposed on the support plate and has a drive source that generates a drive force for pressing at least one of the plurality of abutting portions against the work when gripping the work;
A free movement mechanism that supports at least one of the plurality of contact portions so as to be freely movable with respect to the support plate; and a movement restriction device that restricts free movement by the free movement mechanism;
A workpiece gripping device comprising:
A contact part moving drive device that is provided outside the workpiece gripping device and moves the contact part supported so as to be freely movable;
I have a,
The universal movement mechanism includes a nut member on which the contact portion is disposed, and a screw shaft that is screwed with the nut member.
The contact portion moving drive device, a work grasping system, characterized by chromatic and rotation driving device, and a transmission shaft for transmitting the rotational force of the rotary drive device to said screw shaft. The transmission shaft has a transmission shaft side engaging portion provided at an end portion on the screw shaft side,
The workpiece gripping system according to claim 1 , wherein the screw shaft includes a screw shaft side engaging portion that can be engaged with the transmission shaft side engaging portion. The transmission shaft has a drive shaft positioned on the rotary drive device side, and a driven shaft positioned on the screw shaft side and fitted coaxially so as to be able to transmit rotational force to the drive shaft,
An elastic body is mounted between the drive shaft and the driven shaft, and the drive shaft and the driven shaft are configured to be able to move close to each other in the axial direction against the urging force of the elastic body. The workpiece gripping system according to claim 2 . The abutting portion moving drive device includes a driven shaft displacement detecting unit that detects an axial displacement of the driven shaft, and a displacement that is greater than or equal to a predetermined value of the driven shaft by the driven shaft displacement detecting unit. The workpiece gripping system according to claim 3 , further comprising a recognition unit that recognizes that the screw shaft and the transmission shaft are not normally engaged. The contact part moving drive device includes a contact part displacement detection unit that detects a displacement of the contact part supported so as to be freely movable, and a contact part detection unit that detects the contact part displacement detection unit. workpiece holding system according to any one of claims 1 to 4 displacement and having a control unit for controlling the operation of the rotary drive device such that the target value. The workpiece has a shell portion exhibiting a shell shape,
The workpiece gripping system according to any one of claims 1 to 5 , wherein the contacted portion of the workpiece is located on an outer surface or an inner surface of the shell portion.

Images