JP4285262B2 - Robot workpiece gripping mechanism - Google Patents

Description

  The present invention relates to a workpiece gripping mechanism for a robot, and more particularly to a workpiece gripping mechanism for a robot that enables positioning of the gripped workpiece with a simple configuration without using power or the like.

  In various production sites, a workpiece dispensed from a previous process is transported to the next process via a robot. For example, at the engine production site, a plurality of cylinder heads delivered from the previous process are loaded one by one on each mass of a tray divided into about 20 masses.

The robot used here has a workpiece gripping mechanism coupled to a robot arm. The workpiece gripping mechanism 100 includes a pair of workpiece gripping claws 101 and 102 opposed to each other as shown in FIG. The workpiece gripping claws 101 and 102 are set such that one is a fixed claw and the other is a movable claw, and a movable claw (work gripping claw 101 in the figure) is slid by an air cylinder 103 to bring the workpiece 110 into a fixed claw (work gripping claw in the figure). 102) and positioning and gripping.
However, in such a simple mechanism, if the workpiece is not accurately positioned, it is necessary to secure a certain gap between the fixed claw and the workpiece in anticipation of a slight displacement. If you press, the workpiece may fall down. Further, since the work is not positioned even in the 90 ° rotation direction with respect to the gripping direction, positioning failure occurs, and when the work 110 gripped by the work gripping claws is put into the tray, as shown in FIG. The workpiece 110 may interfere with the tray 120.
For this reason, the conventional workpiece holding mechanism has both a compliance function that has a degree of freedom by the linear guide mechanism and a mechanism that uses an actuator for moving and stopping the workpiece gripping claw. That is, it has a workpiece positioning function (see, for example, Patent Documents 1 and 2).

JP-A-62-68231 JP-A-5-269689

  However, as described above, the conventional robot workpiece gripping mechanism needs to have a mechanism that uses an actuator for moving and stopping in addition to the compliance function for the workpiece gripping claw, so the mechanism is complicated. There was a problem.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a workpiece gripping mechanism of a robot capable of positioning a workpiece with a simple configuration.

Among the present inventions that achieve the object as described above, the invention according to claim 1 is a workpiece gripping mechanism connected to a robot arm.
A workpiece gripping portion having a pair of workpiece gripping claws that are moved in the distance by a fluid pressure cylinder is installed so as to be movable through a linear guide that is tilted with respect to the horizontal. Position regulating means for stopping the downward movement of the workpiece gripping portion on the lower side in the direction of inclination is provided , and the linear guide includes a first surface parallel to a direction in which the pair of gripping claws move far and near The linear guide installed on the first surface and the linear guide installed on the second surface are respectively installed along two directions of the second surface intersecting the first surface. one is through the other linear guide being movable together with the workpiece holding portion, said workpiece holding portion, and a biasing means for pulling the inclination direction upward along at least one linear guide And wherein the door.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the work gripping portion is brought into a floating state in the linear guide by the biasing means.

According to the workpiece gripping mechanism of the robot of the present invention, when the workpiece is gripped by the workpiece gripping claw and pulled up via the robot arm, the workpiece gripping portion moves along with the workpiece along the linear guide that is inclined, Stops at a fixed position determined by the position restricting means. That is, the workpiece can be positioned without using an actuator or the like, and the configuration of the workpiece gripping mechanism can be simplified as much. The position restricting means can be configured by a movement limit mechanically determined between the work gripping means and the linear guide, a stopper provided separately, or the like.
In the present invention, that provide a floating mechanism achieved by such biasing means in the linear guide desirable. In the two-way linear guide , one or both of them can be provided with a floating mechanism. The floating mechanism can solve the interference problem caused by the displacement of the workpiece, and can easily grip the workpiece.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a view of the workpiece gripper 20 connected to the robot arm body 10 as viewed in the X-axis direction, and FIG. 2 shows a view of the workpiece gripping unit 20 as viewed in the Y-axis direction orthogonal to the X-axis. FIG. 3 shows a cross section viewed from the opposite direction of FIG.

  In order to grip the workpiece W, the workpiece gripping portion 20 is installed so that the pair of workpiece gripping claws 31 and 32 face each other so as to be movable in the near and far directions. In other words, one work gripping claw 31 is connected to a fluid pressure (for example, air) cylinder body 33 via a connection plate 34, and the other work gripping claw 32 is moved to and away from the fluid pressure cylinder body 33. 35 is connected via a connecting plate 36. The separation plate 35 is attached to the ends of a piston rod 37 fitted into the fluid pressure cylinder main body 33 and two guide rods 38 on both sides thereof. The guide rods 38 are slidably attached to the cylinder body 33 side. As the fluid is supplied to and discharged from the fluid pressure cylinder body 33, the piston rod 37 expands and contracts, and the contact plate 35 moves away from and contacts the fluid pressure cylinder body 33. Thus, the pair of workpiece gripping claws 31 and 32 can move in the opening and closing direction as indicated by chain lines 31a and 32a.

  As shown in FIGS. 2 and 3, an X-axis plate body 41 is provided on the outer wall of the fluid pressure cylinder main body 33 along the direction in which the piston rod 37 and the guide rod 38 extend and the vertical direction (vertical direction in this embodiment). Are attached to the outer surface of the X-axis plate body 41 along the plate surface of the X-axis plate body 41. A rail 44 is fitted to the guide 43 to constitute an X-axis linear guide 42. The rail 44 is attached to a plate body 45 located opposite to the X-axis plate body 41. A Y-axis plate body 51 extending at right angles to the X-axis attachment plate 45 is connected to one end of the X-axis attachment plate 45, and the Y-axis linear guide 52 is connected to the outer surface of the Y-axis plate body 51. A guide 53 constituting a part is attached. A rail 54 is fitted to the guide 53 to constitute a Y-axis linear guide 52. A Y-axis attachment plate 55 is fixed to the robot arm body 10 so as to hang down, and faces the Y-axis plate body 51 in parallel. A rail 54 is attached to the inner surface of the Y-axis attachment plate 55. .

  The X-axis linear guide 42 constituted by the guide 43 and the rail 44 is parallel to the direction in which the workpiece gripping claws 31 and 32 move in the near and far direction and is a surface along the vertical direction (vertical direction in this embodiment) ( In the first plane), as shown in FIG. 4, the Y-axis plate body 51 side is installed obliquely so as to be lowered. Further, the Y-axis linear guide 52 constituted by the guide 53 and the rail 54 is orthogonal to the first surface and is in a surface (second surface) along the vertical direction (vertical direction in this embodiment). Yes, as shown in FIG. 5, it is installed obliquely so that the X-axis mounting plate 45 side is lowered. That is, the workpiece gripping portion 20 is slidable along the linear guides 42 and 52 within the first surface and the second surface, and more specifically, a pair of workpiece gripping claws 31. , 32, a member including the fluid pressure cylinder main body 33 and the X-axis linear guide 42 is movable obliquely by the Y-axis linear guide 52, and includes a pair of workpiece gripping claws 31 and 32 and a fluid pressure cylinder main body 33. The member can move obliquely by the X-axis linear guide 42. Further, the first surface and the second surface can move in a crossing direction.

  Furthermore, as a biasing member of the present invention, a movable workpiece gripping portion 20 (a member including a pair of workpiece gripping claws 31 and 32, a fluid pressure cylinder body 33, and an X-axis linear guide 42) is provided along the Y-axis linear guide 52. A tension spring 61 is attached to pull up diagonally upward. Specifically, as shown in FIG. 5, one end of a tension spring 61 is connected to a post 62 provided on an end portion of the Y-axis mounting plate 55 (upper end side of the guide 53). The end is stretched so as to be connected to the X-axis mounting plate 45. At this time, the workpiece gripping portion 20 (a member including the pair of workpiece gripping claws 31, 32, the fluid pressure cylinder main body 33, and the X-axis linear guide 42) is unloaded by the tension of the tension spring 61 in the unloaded state. The tension of the tension spring 61 is set so as to float in the middle of the shaft linear guide 52. Further, a stopper arm 63 is suspended from the robot arm body 10 so as to extend to the side of the workpiece gripping claws 31 and 32 on the lower side in the inclination direction of the Y-axis linear guide 52, and the fluid pressure cylinder body. A stopper protrusion 46 that restricts the movement of the workpiece gripping part 20 against the Y-axis plate 51 is provided at the end of the 33-side Y-axis plate 51.

  Next, the operation of the workpiece gripping mechanism of the robot configured as described above will be described with reference to FIGS. FIG. 6A shows that the workpiece gripping portion 20 is lowered together with the robot arm body 10 with the workpiece gripping claws 31 and 32 in the most open state so that the workpiece W is positioned between the workpiece gripping claws 31 and 32. Represents the state. The opened workpiece gripping claws 31 and 32 are moved downward (left side in the drawing) in the X-axis direction according to the inclination of the X-axis linear guide 42, and according to the inclination of the Y-axis linear guide 52 by the tension of the tension spring 61. It is lifted in the Y-axis direction and is in a floating state (see FIG. 7A).

  In the state of FIG. 6A, when the fluid pressure cylinder body 33 and the connecting / disconnecting plate body 35 are operated so as to approach each other by supplying and discharging fluid to the fluid pressure cylinder body 33, as shown in FIG. First, the workpiece gripping claw 32 on the side of the separation plate 35 moves so as to approach the workpiece W and comes into contact with the workpiece W. When the workpiece gripping claw 32 comes into contact with the workpiece W, the piston rod side is fixed and the cylinder main body side becomes movable. Next, the workpiece gripping claw 31 together with the guide 43 approaches the workpiece W along the X-axis linear guide 42. The workpiece gripping claws 31 and 32 grip the workpiece W as shown in FIG.

  When the robot arm body 10 is lifted upward after gripping the workpiece W in this way, the workpiece gripping portion 20 and the workpiece W are moved by the X-axis linear guide 42 as shown by an arrow 21 in FIG. According to the inclination, it moves downward in the inclination direction by its own weight, and stops at a position where the stopper projection 46 and the Y-axis plate body 51 interfere. In the drawing, a stopper protrusion 46 is provided at one end extension of the guide rod 38 so that the stopper protrusion 46 abuts on the Y-axis plate body 51. However, the present invention is not limited to this structure. The mounting position of the part may be changed, or a stopper member that interferes with the fluid pressure cylinder main body 33 may be provided on the Y-axis plate body 52 side, and the structure of the stopper can be changed as appropriate.

Further, when the workpiece W is pulled up, the workpiece gripping portion 20 also moves according to the inclination of the Y-axis linear guide 52 at the same time. This state is shown in FIGS. 7A to 7C. That is, as shown in FIG. 7A, when the workpiece gripping portion 20 that grips the workpiece W is pulled up together with the robot arm body 10, the workpiece W and the workpiece gripping portion 20 are indicated by arrows 22 in FIG. In addition, it moves downward according to the inclination of the Y-axis linear guide 52 against the tensile force of the tension spring 61 by its own weight. The movement according to the inclination of the Y-axis linear guide 52 stops when the workpiece W comes into contact with the stopper arm 63 as shown in FIG. As with the X-axis side, the stopper mounting position and structure can be appropriately changed to known techniques as long as the workpiece W stops at a predetermined position.
As described above, the workpiece gripping claws 31 and 32 that are not gripping the workpiece W and the workpiece W gripped by the workpiece gripping claws 31 and 32 are moved by their own weight according to the inclination of the linear guides 42 and 52, and finally are stopped by a stopper or the like. By restricting the movement, the robot arm body 10 can always be positioned at a fixed position. Further, since the gripping claws easily move due to the inclination of the linear guide, when the workpiece gripping claws 31 and 32 grip the workpiece W, the workpiece gripping claws 31 and 32 interfere with the workpiece W and the workpiece W falls down. Can be prevented.

  The workpieces W gripped by the workpiece gripping claws 31 and 32 can be accommodated in the mass 71 of the tray 70 without being displaced as shown in FIGS. 8A and 8B. W can be smoothly stored without interfering with the partition wall of the mass 71.

  When releasing the gripped workpiece W, the gripping claws 31 and 32 are further separated by extending the piston rod 37 of the fluid pressure cylinder main body 33. At this time, the workpiece gripper 20 is pulled up to the intermediate portion according to the inclination of the Y-axis linear guide 52 by the tension of the tension spring 61 as indicated by the arrow 23 shown in FIG. To do.

As described above, according to the workpiece gripping mechanism of the present invention, a mechanism using an actuator or the like for moving the workpiece gripping portion 20 is not necessary, and the workpiece gripping mechanism can be easily configured.
Although the present invention has been described with the above embodiment, the present invention is not limited to the above description, and can be appropriately changed within the scope of the present invention.

It is sectional drawing of the X-axis direction of the workpiece | work holding | grip mechanism of embodiment of this invention. It is sectional drawing of the Y-axis direction of a workpiece | work holding | grip mechanism similarly. It is sectional drawing on the opposite side to FIG. It is a front view which similarly shows the installation aspect of the X-axis linear guide of a workpiece | work holding | grip mechanism. It is a side view which similarly shows the installation aspect of the Y-axis linear guide of a workpiece | work holding | grip mechanism. It is a figure explaining operation | movement of the workpiece | work holding | grip mechanism of embodiment. Similarly, it is a figure explaining operation | movement of the workpiece | work holding | grip mechanism of embodiment. It is a figure explaining operation | movement similarly, and is the front view which accommodated the hold | gripped workpiece | work in the tray. It is a figure explaining operation | movement similarly, and is the side view which accommodated the hold | gripped workpiece | work in the tray. (A) is a figure explaining the operation | movement which hold | grips a workpiece | work by the conventional workpiece | work gripping mechanism, (b) is a figure which shows the state at the time of accommodating the hold | gripped workpiece | work in a tray.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Robot arm 20 Work holding part 31 Work holding nail 32 Work holding nail 33 Fluid pressure cylinder main body 34 Connecting plate 35 Separation / contact plate 36 Connecting plate 37 Piston rod 38 Guide rod 41 X-axis plate 42 X-axis linear guide 43 Guide 44 Rail 45 Plate 46 Stopper projection 51 Y-axis plate 52 Y-axis linear guide 53 Guide 54 Rail 55 Drooping plate 61 Tension spring 62 Post 63 Stopper arm 70 Tray 71 Mass

Claims (2)

In the workpiece gripping mechanism connected to the robot arm,
A workpiece gripping portion having a pair of workpiece gripping claws that are moved in the distance by a fluid pressure cylinder is installed so as to be movable through a linear guide that is tilted with respect to the horizontal. Position regulating means for stopping the downward movement of the workpiece gripping portion on the lower side in the direction of inclination is provided , and the linear guide includes a first surface parallel to a direction in which the pair of gripping claws move far and near The linear guide installed on the first surface and the linear guide installed on the second surface are respectively installed along two directions of the second surface intersecting the first surface. one is through the other linear guide being movable together with the workpiece holding portion, said workpiece holding portion, and a biasing means for pulling the inclination direction upward along at least one linear guide Workpiece holding mechanism of the robot, characterized and. The robot workpiece gripping mechanism according to claim 1, wherein the workpiece gripping portion is brought into a floating state in the linear guide by the biasing means .

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