JP2668336B2 - Robot arm structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for spot welding, handling heavy objects, etc., and has a non-parallel link type multi-joint in which a vertical arm supports a drive motor for driving each axis of its own wrist. Regarding the arm structure of industrial robots, especially for industrial robots that require a wide operating range and small installation space, without extending the operating arm,
The present invention relates to a robot arm structure capable of expanding an operation range and lowering the height of a robot.

[0002]

2. Description of the Related Art A conventional non-parallel link type articulated industrial robot in which a vertical axis arm supports a drive motor for driving each axis of its own wrist is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 62-27.
It is known as 7292 (Japanese Patent Publication No. 04-043742). In such a non-parallel link type articulated industrial robot, the operating range in the up-down direction could be partially supplemented by utilizing the supplementary platform / pit. Was often requested. However, it is not easy to expand the range of movement in the front-rear direction, and a traveling device that can move in the front-rear direction with a robot as necessary was used.However, the traveling device itself is expensive, so the cost of the entire system increases. It was inevitable. For this reason, conventionally, as a method of extending the operation range of such a non-parallel link type articulated industrial robot, a method of extending the operation arm or an operation angle of the operation arm has been generally adopted.

[0003]

However, in such a conventional non-parallel link type multi-joint robot as shown in FIG. 3, the front and rear axis arms 29 and 22 are extended to extend the front and rear direction of the robot. Extending the vertical arm 21 in order to enlarge the vertical direction causes an increase in unbalance torque and inertia, which requires a larger motor and a reduction gear. Also, it was necessary to increase the rigidity of each shaft arm, and each shaft arm became thicker, which led to an increase in weight. For the above reasons, eventually, an increase in the size of the robot body and an increase in cost were unavoidable. In addition, for a robot that requires space saving, an increase in the size of the robot has resulted in an increase in layout and a restriction on a use place. As can be seen from FIG. 3 which shows the operation range of the conventional non-parallel link type articulated robot in which the vertical axis arm 21 is extended to expand the vertical direction, the robot is separated from the robot simply by extending the operation arm. The operating range L is formed at the place, and the installation space of the robot is inevitably expanded. In addition, when the front and rear shaft arms 22 and 29 become longer, the height of the robot becomes higher, and there is a restriction that the robot cannot be installed in a place with a low ceiling such as a conveyor. Next, in the method of enlarging the operation angle of the operation arm, when the operation angle of the operation arm is increased, the cable wired from the front-rear axis arm to the vertical axis arm becomes severely bent, and the life of the cable is remarkably reduced. In addition, there is a problem that the resolution of the position detector is reduced due to the expansion of the operation angle.

An object of the present invention is to provide a non-parallel link type articulated industrial robot in which the vertical axis arm supports a drive motor for driving each axis of its own wrist, without easily extending the operation arm. An object of the present invention is to provide a robot arm structure capable of expanding the operation range inexpensively. Another object of the present invention is to provide a robot arm structure in which the height of the robot can be reduced without shrinking the operation arm in the non-parallel link articulated industrial robot. Still another object of the present invention is to provide a robot arm structure in which the drive motor of the longitudinal axis arm can be reduced in the non-parallel link type articulated industrial robot. Another object of the present invention is to provide an arm structure of a robot in which the non-parallel link type articulated industrial robot can improve the gravity balance of the vertical axis arm and reduce the counterbalance weight of the vertical axis arm. .

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a non-parallel link type articulated industrial robot in which a vertical arm supports a drive motor for driving each axis of its own wrist. The horizontal pivot shaft of the vertical shaft arm is arranged at the upper end of the arm, and the upper end of the mounting structure having an L-shaped cross section viewed from the rear is pivotally supported by the horizontal pivot shaft, and the L-shaped mounting structure is provided. A vertical portion or a bottom portion of the vertical axis arm base to be supported by being offset downward with respect to the horizontal pivot shaft, and a vertical portion or a bottom portion of the L-shaped mounting structure for the vertical axis arm wrist. The problems of the prior art described above have been solved by providing an arm structure of a non-parallel link type robot characterized by supporting a drive motor for driving each axis.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 (a) shows an embodiment in which the vertical arm 1 according to one embodiment of the present invention drives drive shafts 61, 62,
3 shows the configuration of a non-parallel link articulated industrial robot adapted to support 63. The robot of the present invention has a base 8
A swivel 9 is mounted on the swivel 9 so as to be swivelable about a vertical axis 12, and a horizontal pivot 10 is arranged at the upper end of the swivel 9. Two are pivoted. The vertical arm 1 is vertically movable about a horizontal pivot 3 disposed at an upper end 11 of the front and rear arm 2.
Is pivoted.

In the present invention, FIG. 1 (b) is an enlarged partial rear view of the upper end portion of FIG.
As can be clearly seen from FIG. 1 (c), which is an enlarged partial side view viewed from the right arrow C direction in FIG. 1 (b), the upper and lower shaft arms 1 The horizontal pivot shaft 3 is disposed, and the horizontal pivot shaft 3 pivotally supports the mounting structure 4 having an L-shaped cross section as viewed from the rear surface, and the bottom portion 48 of the L-shaped mounting structure 4.
(Alternatively, it may be attached to the vertical part 47). The vertical axis arm base 1 'is supported by being offset downward with respect to the horizontal pivot shaft 3, and the bottom of the L-shaped mounting structure 4
A driving motor 61, 62, 63 for driving each axis (not shown) of the wrist 13 of the vertical axis arm 1 is supported on 48 (alternatively, it may be attached to the vertical section 47). Figure 1 (a) (b)
In (c), for convenience of explanation, the cross-sectional profile of the L-shaped mounting structure 4 of the embodiment is shown by hatching with chain lines. In this embodiment, the vertical axis arm driving motor 5 is arranged substantially coaxially with the horizontal pivot shaft 3, and the driving motors 61, 62, 63 for driving the respective axes of the wrist 7 are arranged on the opposite side of the vertical axis arm 1 to the wrist. It is arranged to protrude.

The L-shaped mounting structure 4 of the embodiment has a mounting flange 45 for the vertical shaft arm 3 facing the horizontal pivot shaft 3 of the vertical shaft arm 1 and a back side of the mounting flange 45 for the vertical shaft arm. A vertical axis arm drive motor 5 mounting flange 46 and a vertical axis arm base 1 'mounting flange 44 which is perpendicular to the vertical axis arm mounting flange 45 and offset downward.
And shaft drive motor mounting flanges 41, 42, 43 for mounting the shaft drive motors 61, 62, 63 of the wrist 13 on the back side of the vertical shaft arm base mounting flange 44, respectively. These flanges and the counterpart vertical shaft arm 3, the vertical shaft arm drive motor 5, the vertical shaft arm base 1'and the shaft drive motors 61, 62 and 63 of the wrists 13 are not shown in the drawings but are suitable mounting devices for suitable bolts and the like. Is attached using.

FIG. 2 (a) shows the non-parallel link type articulated industrial robot of the present invention shown in FIG. 1 (a), and the movement range RR drawn by the center point A of the wrist 13 and the conventional art shown in FIG. 2 (b). Range R drawn by the center point A of the wrist of the non-parallel link type articulated robot
And shows the comparison. In order to equalize the load of the drive system, the length of the vertical axis arm 1 of the robot, that is, the distance L1 between the center of the horizontal pivot axis 3 and the center point A of the wrist, the height H1 between the base 8 and the swivel bases 9, 29, and The operation angles θ1 to θ5 are the same. The length L1 of the vertical arm 1 in FIG. 2 (a) is the oblique distance between the center of the horizontal pivot shaft 3 and the center point A of the wrist 7, and (L1) ² = (L12) ² + (H14) ² The dimensions of L12 and H14 are selected so that

As a result, when FIG. 2 (a) and FIG. 2 (b) are overlapped with each other, the distance R1 between the horizontal motion axis 10 and the forward motion range of the robot when it is tilted forward is the same, but The motion range RR of the robot in the front-rear direction of FIG.
3 is expanded to R13 in FIG. 2A, and is expanded by an operating range RE indicated by oblique lines. Fig. 2 (b)
From H3 of FIG. 2 to H13 of FIG. That is, R1 = R1, but R13> R3 H13 <H3.

[0011]

As described above, in the robot arm structure according to the present invention, the L-shaped mounting structure allows the base of the vertical axis arm to be supported by being offset downward with respect to the horizontal pivot axis of the vertical axis arm. Therefore, the operation range of the robot can be extended in the front-rear direction without extending the operation arm of the robot, that is, without increasing the layout, and the operation range of the robot can be reduced without reducing the operation arm of the robot. The height of the robot can be reduced without any problem. In addition, since the drive motors for driving the respective axes of the wrist are mounted so as to be offset downward with respect to the horizontal pivot shaft, the center of gravity of the front-rear shaft arm is lowered, and the drive motor for the front-rear shaft arm can be reduced. More preferably, when the vertical axis arm drive motor is arranged substantially coaxially with the horizontal pivot shaft, the vertical axis arm drive motor and the vertical axis arm are arranged in series, which enables reduction of the number of parts and cost, and further preferably When the drive motors for driving the respective axes of the wrist are arranged so as to protrude from the wrist side of the upper and lower arm, the gravity balance of the upper and lower arm can be improved and the counter balance weight of the upper and lower arm can be reduced.

[Brief description of the drawings]

FIG. 1A is a schematic side view showing the configuration of a non-parallel link type articulated industrial robot according to an embodiment of the present invention;
(b) is an enlarged rear view of the upper end of FIG. 1 (a) viewed from the back B direction, and FIG. 1 (c) is an enlarged view viewed from the right C arrow view of FIG. 1 (b). Partial side view, respectively. For convenience of explanation, the cross-sectional outline of the L-shaped mounting structure 4 of the embodiment is indicated by chain-line hatching.

FIG. 2A is a schematic side view showing an operation range RR drawn by a center point A of a wrist of the non-parallel link type articulated industrial robot of the present invention in FIG. 1A; b) is a schematic side view showing a motion range R drawn by the center point A of the wrist of a conventional non-parallel link type multi-joint robot. In order to make the load of the drive system equal, the length of the vertical axis arm of the robot, that is, the horizontal axis is shown. The distance L1 between the center of the moving shaft 3 and the center point A of the wrist 7, the height H1 between the base 8 and the swivel table 9, and the operation angles θ1 to θ5 are the same.

FIG. 3 shows a motion range R drawn by the center point A of the wrist of the conventional non-parallel link type articulated robot shown in FIG. 2B and a center point A of the wrist of the robot when the vertical axis arm 21 is extended. It is a schematic side view which respectively shows the movement range L to draw.

[Explanation of symbols]

1. . Vertical axis arm 1 '. . Vertical arm base 2. . Front and rear axis arm 3. . Horizontal pivot axis 4. . L-shaped mounting structure 5. . Vertical axis arm drive motor 11. . Upper end of longitudinal arm 13. . Wrists 41,42,43. . Drive motor mounting flange to drive each axis of wrist 44. . Vertical shaft arm base mounting flange 45． . Mounting flange on vertical arm 46. . Vertical axis arm drive motor mounting flange 47. . Vertical part of L-shaped mounting structure 48. . Bottom of L-shaped mounting structure 61,62,63. . Drive motor that drives each axis of the wrist

Claims (3)

(57) [Claims] 1. A non-parallel link type articulated industrial robot in which a vertical arm supports a drive motor for driving each axis of its own wrist. A pivot shaft is arranged, and the horizontal pivot shaft pivotally supports the upper end of the mounting structure having an L-shaped cross section when viewed from the rear surface, and the vertical shaft is provided at the vertical portion or bottom of the L-shaped mounting structure. An arm base is supported by being offset downward with respect to the horizontal pivot axis, and a drive motor for driving each axis of the wrist of the vertical axis arm is supported on a vertical portion or a bottom portion of the L-shaped mounting structure. An arm structure of a robot characterized by having been performed. 2. The vertical arm driving motor is arranged substantially coaxially with the horizontal pivot axis of the vertical arm, and a driving motor for driving each axis of the wrist is provided on the opposite wrist side of the vertical arm base. 2. The arm structure of a robot according to claim 1, wherein the arm structure is arranged so as to protrude. 3. The L-shaped mounting structure includes a mounting flange for the vertical shaft arm facing the horizontal pivot shaft of the vertical shaft arm, and a vertical shaft arm drive on the back side of the mounting flange for the vertical shaft arm. A motor mounting flange, an upper and lower axis arm base mounting flange perpendicular to and offset from the mounting flange to the upper and lower axis arms, and a shaft mounting motor mounting flange for each of the wrists behind the upper and lower axis arm base mounting flange. The arm structure of a robot according to claim 1 or 2, further comprising: