JP2011240450A - Robot arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot arm with a structure capable of obtaining buffering action by a relatively simple structure.SOLUTION: An XθZ type wire-driven robot arm includes a first arm 1 which turns by a θ-axis rotating means 7 and a second arm 2 coupled with a tip of the first arm 1 and capable of swinging vertically and laterally. The robot arm includes a working area at the tip of the second arm 2, supports a laterally swinging axis 4 at the tip of the first arm 1, supports a vertically swinging axis 5 supported by a base of the second arm 2 on the laterally swinging axis 4, and includes a buffering means 6 between the first arm 1 and the second arm. The buffering means 6 includes a posture keeping means for guiding the second arm 2 to a regular posture with respect to the first arm 1 and a retreat means capable of guiding the second arm 2 so that the tip of the second arm 2 can move to the right and left and upward from the regular posture with respect to the first arm 1.

Description

  The present invention relates to a robot arm that employs an XθZ drive system (a drive system comprising a linear movement in the X-axis direction, a turn in the θ-direction, and a linear movement in the Z-direction parallel to the rotation axis), and particularly a collision or the like. The present invention relates to a buffer means for a robot arm against the above.

The robot arm performs drive control of each joint by servo control, generates a desired motion, and is used for manufacturing and processing.
However, for example, there may be obstacles in the operating area of the robot arm during alignment or when the environment changes significantly, and there is a risk of damage or personal injury due to the robot arm colliding with the obstacle. Occurs.

  Therefore, various techniques for detecting a collision by a sensor, releasing torque and reversing the operation have been introduced (for example, refer to the following patent document).

Japanese Patent Laid-Open No. 2003-039376 Japanese Patent Laid-Open No. 11-207682

  However, since the conventional method is a method of performing buffering only by drive control, the buffering at the moment of collision is insufficient. For this reason, such a method alone has effectively limited the effect of eliminating the collision state rather than preventing the damage caused by the collision.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot arm having a structure that can provide a buffering action with a relatively simple structure.

  The robot arm according to the present invention, which has been made to solve the above problems, is an XθZ drive type robot arm, and is connected to a first arm that is rotated by θ rotation means such as a motor, and a tip of the first arm. A second arm that can swing vertically and horizontally is provided, and the tip of the second arm can be rotated with a working portion, i.e., a shaft parallel to the vertical shaft through a pulley and a belt as a rotation axis. A work tool such as a chuck, or a support region where the work tool can be attached and detached.

As the connecting portion of the first arm and the second arm, the tip end portion of the first arm and the base end of the second arm are stacked one above the other (whichever is upper), for example, on the tip end portion of the first arm A structure in which a horizontal rocking shaft is supported and a vertical rocking shaft supported by the base of the second arm is supported by the horizontal rocking shaft, or a horizontal rocking shaft is supported by the base of the second arm, A structure in which the vertical swing shaft supported by the tip of the first arm is supported by the swing shaft, or a ball bearing is connected to the first arm so that the second arm can swing vertically and horizontally. Any of the configurations can be adopted.
Furthermore, the robot arm according to the present invention is provided with a buffer means between the first arm and the second arm, and the buffer means is a posture for guiding the second arm to a steady posture with respect to the first arm. It is characterized by comprising a maintaining means and a retracting means for guiding the tip of the second arm left and right and upward from a steady posture with respect to the first arm.

The buffer means may be constituted by a valley-shaped guide surface including slopes facing each other and a protrusion that contacts the guide surface. Here, the form of the valley-shaped guide surface including the slope may be a mortar shape or a spherical shape.
In this case, the buffer means is provided with the guide surface in front of or behind the connecting portion including the horizontal swing shaft, the vertical swing shaft, or the ball bearing in one of the first arm and the second arm. The protruding portion is provided on the other of the first arm and the second arm so as to face the guide surface.

  If the protrusion is provided with a contact portion made of a magnetic material and a magnet that attracts or attracts the contact portion to the deepest portion of the guide surface, the adjustment of the magnetic force causes a steady posture. Maintenance / induction strength can be adjusted. In addition, as a method (return means) for pulling the contact portion to the deepest portion of the guide surface, the angle between the first arm and the second arm is restored so that the contact portion goes to the deepest portion of the guide surface. A coil spring or a leaf spring that biases as much as possible can also be used.

  The robot arm according to the present invention adopts the XθZ drive method, and thus the trajectory of the arm at each joint is temporarily compared with a multi-joint arm (hereinafter abbreviated as a “multi-joint arm”) that requires a rotation amount control at each joint. While easy to remove, it is possible to obtain an operating range and accuracy that are not inferior to the articulated arm, and convenience of control.

  As described above, as a result of temporarily allowing the arm trajectory to be removed at each joint, the lateral swing shaft is supported at the distal end portion of the first arm, and the base portion of the second arm is supported on the lateral swing shaft. A posture maintaining means for supporting the vertical swing shaft to be supported and guiding the second arm to a steady posture with respect to the first arm, and a tip of the second arm from the steady posture with respect to the first arm to the left and right and upward. It can be set as the structure which has a buffer means provided with the retractable means which can be guided.

  Due to the presence of the buffering means, sufficient buffering can be performed at the moment of collision, and damage caused by the collision can be prevented and reduced. In addition, when used in combination with the prior art, the collision state can be resolved based on the detection result by the sensor while the second arm is retracted by a certain amount. Will also be convenient.

It is an exploded view which shows an example of the robot arm by this invention. It is a principal part enlarged view which shows an example of operation | movement of the robot arm by this invention. FIG. 2A is a plan view and FIG. 2B is a side view in a steady posture showing an example of a robot arm according to the present invention. An example of operation | movement of the robot arm by this invention is shown, (A) is a top view, (B) is a side view. An example of operation | movement of the robot arm by this invention is shown, (A) is a top view, (B) is a side view. An example of operation | movement of the robot arm by this invention is shown, (A) is a top view, (B) is a side view. It is the principal part perspective view seen from the front side which shows an example of the robot of the X (theta) Z drive system which can use the robot arm by this invention. It is the perspective view seen from the back side which shows an example of the Z-axis drive means in the robot of the X (theta) Z drive system which can use the robot arm by this invention. It is the perspective view seen from the back side which shows an example of the X-axis drive means in the robot of the XthetaZ drive system which can use the robot arm by this invention.

Embodiments of a robot arm according to the present invention will be described below with reference to the drawings.
The embodiment shown in FIG. 1 is a robot arm used for an XθZ drive type robot.
In the XθZ drive system in the present embodiment, a motor that is the θ rotation means 7 and a vertical shaft that is driven by the motor are mounted on the Z-axis drive means 8 that is driven by the motor, It is mounted on the shaft drive means 9.
In the present embodiment, by fixing the base end portion of the robot arm to the vertical shaft 7a driven by the motor, the vertical shaft 7a can be moved up and down, left and right, and the robot arm fixed to the vertical shaft 7a can be turned. To do.

  The robot arm of the present embodiment includes a first arm 1 whose base end is directly fixed to the vertical shaft 7a and subjected to turning control about the vertical shaft 7a, and a base end at the front end of the first arm 1. And a chuck 3 that can be rotated by the vertical shaft via a pulley 28 and a belt (not shown) at the tip of the second arm 2. .

The robot arm of the present embodiment has a structure in which the base end portion of the second arm 2 is overlapped below the tip end portion of the first arm 1, and the first arm 1 and the second arm 2 are mutually connected. A joint part to be connected is provided.
The joint portion includes vertical and horizontal hinge mechanisms and buffering means 6. However, as a structure for moving the chuck 3 to a position (action point) where the chuck 3 should perform its function, the connection angle of the second arm 2 with respect to the first arm 1 and the like are set. No change is made in terms of control, and only a retreat operation is performed between the first arm 1 and the second arm 2 to relieve an impact caused by a collision with an obstacle.

The hinge mechanism of the present embodiment is a combination of vertical and horizontal hinge mechanisms. That is, a bifurcated bearing 2a is provided at the base end portion of the second arm 2, and the lateral swing shaft 4 is loosely fitted into the crotch portion 2b of the bearing 2a. The shaft hole 2c of the bearing 2a and the lateral swing shaft 4 are provided. The vertical swing shaft 5 is communicated with the shaft hole 4a, and the upper end portion of the horizontal swing shaft 4 is rotatably supported in the shaft hole 1a at the tip of the first arm 1 so as not to be detached. Yes (see FIG. 1).
With the above structure, the horizontal swing shaft 4 swings up and down and swings left and right at the base end of the second arm 2 (see FIG. 4).

  The buffering means 6 of the present embodiment includes a posture maintaining means for guiding the second arm 2 to a steady posture in which the second arm 2 is disposed on an extension line of the first arm 1, and the steady posture with respect to the first arm 1. A retracting means capable of guiding the tip of the second arm 2 to the left and right and upward from (see FIG. 3) is integrated.

  The buffer means 6 of the present embodiment includes a valley-shaped guide surface 29 including slopes 6a facing each other, and a protrusion 6b that contacts the guide surface 29. The guide surface 29 is connected to the first arm 1 and the first arm. The protrusion 6 b is provided on the other of the first arm 1 and the second arm 2, and provided on the rear side of the horizontal swing shaft 4 and the vertical swing shaft 5 in either one of the two arms 2.

  In the example shown in FIGS. 1 and 2, a pin having a spherical surface is attached to the hole 1 b of the first arm 1 in order to provide the protrusion 6 b on the back surface of the first arm 1, and the second arm 2. A pair of planar slopes 6a and 6a in contact with the protrusion 6b is formed on the upper surface of the second arm 2 by cutting out the base end of the second arm 2 so that the cross-sectional shape is valley-shaped from the upper surface side. A series of guiding surfaces 29 are formed by connecting with curved surfaces curved with a curvature of.

  The posture maintaining means of the present embodiment employs a magnetic pin as the pin serving as the protrusion 6b, and the valleys of the pair of slopes 6a, 6a (the deepest region between the pair of slopes 6a, 6a). The magnet 6ab for attracting the pin is fixed to the part). The trough portion of the guide surface 29 is configured such that the gap and the inclination of the pair of slopes 6a, 6a are configured so that the trough portion and the spherical surface of the tip end portion (contact portion 6aa) of the pin can be supported without backlash. Combined with the magnetic force adjustment of 6ab, it is possible to prevent displacement and swing of the second arm 2 against vibration and impact during normal operation (see FIG. 6).

The robot arm according to the present invention is configured as described above, and the tip of the second arm 2 is directed left and right upward with respect to the first arm 1 by an impact from the side that surpasses the fixing force of the magnet 6ab. Retracted (see FIGS. 2 and 4), and the tip of the second arm 2 is retracted upward with respect to the first arm 1 by an impact from below that exceeds the fixing force by the magnet 6ab (see FIG. 2). 5).
When the pressure from the obstacle is released, the second arm 2 returns to a normal posture while the projection 6b traces the slopes 6a and 6a by its own weight (see FIG. 2) (see FIG. 3). In the above configuration, if a magnet sensor is attached to the protrusion 6b, it is possible to electrically detect the state where the robot arm is out of the normal posture.

Hereinafter, the XθZ driving method of the present embodiment will be described.
The vertical shaft 7 a to which the robot arm is fixed is provided vertically upward from the θ rotation means 7.
The θ rotation means 7 of the present embodiment includes a motor fixed to the arm base 10 via a stay 11 and a speed reducer connected to the rotation shaft thereof. The axis is a vertical shaft 7a (see FIG. 7).

The arm base 10 is slidably mounted on travel guides (guides in the X-axis direction) 12a and 12b passed over a base frame (not shown) under the control of the control means (FIG. 7). reference).
The base frame of the present embodiment includes left and right side plates and a bottom plate that supports the left and right side plates so as to stand vertically.
The left and right plate is provided with a pair of upper and lower traveling guides 12a and 12b on the lower front portion and the upper rear portion so as to be parallel to each other.

The arm base 10 includes a traveling base 10a and a lifting base 10b.
The traveling base 10a has a back plate 10ab standing vertically on the rear side of the board 10aa (see FIG. 7).

The back plate 10ab includes an upper support portion 10c through which the upper travel guide 12a is inserted, and a pair of left and right transmission pulleys 13a and 13b constituting the Z-axis drive means 8 are provided at substantially the same height in the middle portion of the back plate 10ab. It supports with the rotating shaft perpendicular | vertical with respect to the surface of the backplate 10ab (refer FIG. 7).
Further, the back plate 10ab includes two wire fixing mechanisms 15 and 15 that support both ends of the traveling wire 14 (see FIGS. 7 and 9). The wire fixing mechanisms 15 and 15 receive a traveling force from the X-axis driving means 9 through the traveling wire 14 fixed thereto.
The substrate 10aa includes a lower support portion 10d through which the lower traveling guide 12b is inserted at a front portion thereof, and a pair of left and right lifting guides (guides in the Z-axis direction) that stands vertically from the surface of the bottom plate at an intermediate portion of the depth. ) 16 and 16 (see FIGS. 7 and 8).
The upper and lower guides 16 and 16 are fixed at the top by a top plate 10e that is fixed to the upper portion of the back plate 10ab so as to protrude forward.

The lifting base 10b includes a lifting base body 10ba and a passive body 10bb that receives the lifting force from the Z-axis driving means 8.
The lift base body 10ba includes support portions 10f and 10f through which the lift guides 16 and 16 are inserted, and fixes the stay 11 on the front surface thereof (see FIG. 7).
The passive body 10bb supports a pair of upper and lower passive pulleys 17a and 17b constituting the Z-axis driving means 8 with a rotation axis perpendicular to the surface of the passive body 10bb.
The lift base 10b is integrated by fixing the passive body 10bb between the guide holes provided in the support portions 10f, 10f of the lift base body 10ba.

  By attaching the elevating base 10b to the elevating guides 16 and 16 of the traveling base 10a, the elevating base 10b is moved up and down along a track regulated by the elevating guides 16 and 16, and at this time, the passive body 10bb is a pair. The elevating force by the Z-axis driving means 8 is received via the elevating wire 18 while elevating in the region sandwiched between the rotation shafts of the transmission pulleys 13a and 13b.

The X-axis drive means 9 of the present embodiment includes a motor 19 as a traveling drive source fixed to the right end of the bottom plate of the base frame, and has the following configuration (see FIG. 9).
That is, one end of the traveling wire 14 spirally wound around the driving pulley 20 fixed to the shaft of the traveling drive source is pulled out, and one of the pair of right relay pulleys 21 and 21 having the same coaxial diameter supported by the right side plate is continued. After being hooked on the left relay pulley 22 supported on the left side plate, one end of the traveling wire 14 is fastened to one of the wire fixing mechanisms 15 and 15 provided in the back plate 10ab.
Further, the other end of the traveling wire 14 spirally wound around the driving pulley 20 is pulled out, and the other of the pair of coaxial pulleys 21 and 21 having the same diameter and supported on the right side plate, followed by the wire provided in the back plate 10ab. Fastened to the other of the fixing mechanisms 15 and 15.

  With the above configuration, when the traveling drive source performs forward and reverse rotation, traveling in the X-axis direction according to the amount of rotation becomes possible.

The Z-axis drive means 8 of the present embodiment includes a motor 23 as a lifting drive source fixed to the left end of the bottom plate in the base frame, and has the following configuration.
That is, one end of the lifting wire 18 spirally wound around the driving pulley 24 fixed to the shaft of the lifting drive source is pulled out, hung on the swing relay pulley 25 supported below the left side plate, and then the back plate 10ab. After hanging on the left transmission pulley 13a supported on the left side, it is hung on the upper passive pulley 17a included in the passive body 10bb, and further on the right transmission pulley 13b supported on the right side of the back plate 10ab from below. Fastened to the wire fixing mechanism 27 provided.

  In addition, the other end of the elevating wire 18 spirally wound around the driving pulley 24 fixed to the shaft of the elevating drive source is pulled out and hung on the fixed relay pulley 26 supported on the upper side of the left side plate, and then the back plate After hanging on the left transmission pulley 13a supported on the left side, it is hung on the lower passive pulley 17b included in the passive body 10bb, and further on the right transmission pulley 13b supported on the right side of the back plate 10ab. Fastened to the wire fixing mechanism 27 provided.

  With the above configuration, the elevating drive source performs normal rotation and reverse rotation, so that it is possible to move up and down in the Z-axis direction according to the rotation amount.

  On the basis of the above structure, a platform or the like that supports the object to be processed is appropriately attached to provide a robot according to the purpose of use.

1 first arm, 1a shaft hole, 1b hole,
2 second arm, 2a bearing, 2b crotch, 2c shaft hole,
3 chuck,
4 laterally swinging shaft, 4a shaft hole,
5 vertical swing axis,
6 buffer means, 6a slope, 6aa contact part, 6ab magnet, 6b protrusion,
7 θ-axis rotating means, 7a vertical shaft,
8 Z-axis drive means, 9 X-axis drive means,
10 arm base,
10a traveling base, 10aa substrate, 10ab back plate,
10b elevating base, 10ba elevating base body, 10bb passive body,
10c upper support, 10d lower support,
10e top plate, 10f support part,
11 Stay,
12a upper travel guide, 12b lower travel guide,
13a Left transmission pulley, 13b Right transmission pulley,
14 running wires, 15 wire fixing mechanisms,
16 Lifting guide,
17a Upper passive pulley, 17b Lower passive pulley,
18 lifting wire,
19 Motor (X axis)
20 Driving pulley (X axis), 21 Right relay pulley, 22 Left relay pulley,
23 Motor (Z axis)
24 driving pulley (Z axis), 25 swing relay pulley, 26 fixed relay pulley,
27 wire fixing mechanism,
28 pulleys, 29 guide surfaces,

Claims (3)

In the robot arm of XθZ drive robot,
a first arm (1) that is turned by a θ-axis rotating means (7);
A second arm (2) connected to the tip of the first arm (1) and swingable up and down and left and right;
A buffer means (6) is provided between the first arm (1) and the second arm,
The buffer means (6)
Posture maintaining means for guiding the second arm (2) to a steady posture with respect to the first arm (1);
A robot arm comprising a retracting means capable of guiding the distal end portion of the second arm (2) left and right and upward from a steady posture of the second arm (2) with respect to the first arm (1). The buffer means (6) includes a valley-shaped guide surface (29) including slopes (6a) facing each other, and a protrusion (6b) that contacts the guide surface (29).
The guide surface (29) is provided on one of the first arm (1) and the second arm (2),
The robot arm according to claim 1, wherein the protrusion is provided on the other of the first arm (1) and the second arm (2). Provided with a contact portion (6aa) made of a magnetic material at the tip of the projection (6b),
The robot arm according to claim 2, further comprising a magnet (6ab) for attracting the contact portion at a deepest portion of the guide surface (29).

Images