Industrial robot having a suspended unit

The Cableveyor may be able to support its own weight in the direction of gravity since the Cableveyor having the bent portion that connects between the straight-moving unit and the rotating unit is arranged so that it bends in a horizontal plane. As a result, the Cableveyor and the maintenance member do not collide, thus collision noise or dust caused by the collision can be suppressed. Moreover, since the Cableveyor is arranged to the side of the straight axis, the height size of the robot can be suppressed compared with the composition that arranges the Cableveyor on the upper surface of the straight axis.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2007-296801 filed on Nov. 15, 2007, the description of which is incorporated herein by reference,

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates to an industrial robot that suspends a suspended unit movably in a straight line on a straight axis that is fixed on a stationary part.

2. Description of the Related Art

In the case where an industrial robot is introduced into a small installation, a perpendicularly intersected type industrial robot is used. This type of the industrial robot has two straight-moving axes that are perpendicularly intersected. In order to supply signal wires and power supply lines to movable parts disposed on the straight-moving axes, the wires and lines are passed through in a cable supporting means.

The cable supporting means is arranged so that its bending direction is perpendicular to the supporting surface of the cable supporting means as disclosed in Japanese Patent Application Laid-Open Publications No. 2003-83473 and No. 2000-161447, for example.

For this reason, noise and dust occurs when a suspended unit moves because of an occurrence of a collision by a weight of the cable supporting means acting in the direction of gravity and a movement force of the cable supporting means existing above the suspended unit that moves towards the supporting surface side of the cable supporting means.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve the issue described above, and has as its object to provide an industrial robot having a suspended unit that can suppress the occurrence of noise and dust from the cable supporting means when the suspended unit moves.

In the industrial robot having a suspended unit according to a first aspect, there is provided an industrial robot having a suspended unit comprising a straight axis fixed on a stationary part, a suspended unit suspended movably in a straight line on the straight axis, and a cable supporting means having a bent portion with a curved surface located on a side of the straight axis which connects between the straight axis and the suspended unit.

In addition, the cable supporting means extends in the direction parallel to the longitudinal direction of the straight axis at the side of the straight axis.

Since the cable supporting means is arranged so that the bending direction becomes parallel to the longitudinal direction of the straight axis, the cable supporting means may be able to support its own weight in the direction of gravity.

As a result, the cable supporting means always touches a supporting surface of the maintenance member and moves according to a movement of the suspended unit regardless of a movement or a present position of the suspended unit, a collision does not occur, and the noise and the dust accompanying the collision can be suppressed.

In the industrial robot having a suspended unit according to a second aspect, the cable supporting means is arranged at a lower position than an upper most position of the robot.

In the industrial robot having a suspended unit according to a third aspect, the suspended unit is provided with an elevating part, and the cable supporting means is located in the higher position than the upper most position of the elevated elevating part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, hereinafter will be described a first embodiment of the present invention.

FIG. 1shows a perspective diagram of an industrial robot having a suspended unit,FIG. 2shows an elevational view of the industrial robot, andFIG. 3shows an upper surface view of the industrial robot.

By the way, illustrations of cables, compressed air pipes, etc. are omitted in theseFIGS. 1,2, and3.

The industrial robot1comprises a rotating unit (equivalent to a suspended unit)3suspended movably in a straight line from the straight-moving unit2. The industrial robot1is installed in a lo predetermined workspace (not shown) by fixing it to a ceiling (not shown, equivalent to a stationary part) or to a leg part (not shown, equivalent to a stationary part), for example. The industrial robot1may be fixed horizontally, vertically or in any direction; however, the industrial robot1in this embodiment is fixed horizontally.

The straight-moving unit2is constituted mainly with a straight axis4. A guide rail5is formed in the straight axis4along its longitudinal direction, and it is equipped with a pair of sliders6movably in a straight line along with the guide rail5. The straight axis4is provided with a ball screw (not shown), and the ball screw is screwed to a nut (not shown) that is fixed to the sliders6. The ball screw is designed to rotate in the state where its rotation is slowed down by a connecting unit8by a motor for straight-moving axes7(simplified to “motor” hereafter). The sliders6move in a straight line with the rotation of the motor7along with the guide rail5.

The motor7is fixed to the connecting unit8via a base member9. The base member9is horizontally projected from the straight axis4, and there is provided a box connector10on one side of the projected part. There is provided a box11on another side of the base member9so that a box11may become horizontal, and not shown cables (power cables, signal cables) and compressed air tubes are introduced in the box11through the box connector10. A suspension base12is engaged with an undersurface of the sliders6, and the rotating unit3is fixed to the suspension base12.

FIG. 4is a perspective diagram showing an undersurface of the industrial robot1, and rotating unit3is removed for an easy explanation. The suspension base12is a member to which the rotating unit3is screwed on, and a cover member13and an L-shaped cable duct are formed on the side of the suspension base12integrately.

An end of a Cableveyor (registered trademark)15as a cable supporting means is connected to the box11, and the Cableveyor15is extended to the direction parallel to the longitudinal direction of the straight axis4along with the straight axis4(i.e., to the horizontal direction). The Cableveyor15has a bent portion with a curved surface and connected to the box11between the straight-moving unit2and the rotating units3in the state where the bending direction is parallel to the longitudinal direction of the straight axis4(i.e., to the horizontal direction).

A long plate-like maintenance member16is fixed to the side of the straight axis4via the spacer17along with the longitudinal direction of the straight axis4, and the Cableveyor15installed in accordance with the side of the straight axis4from the box11is touching along with the maintenance member16.

The Cableveyor15is connected to the cable duct14with its intermediate part being bent back to the direction parallel to the longitudinal direction of the straight axis4(i.e., to the horizontal direction).

The straight-moving unit2is constituted as mentioned above, so and the rotating unit3is fixed to the suspension base12that constitutes the straight-moving unit2. The cables and compressed air tubes that pass through in the Cableveyor15and the cable duct14are connected with the rotating unit3. Here, the Cableveyor15is arranged so that it may become lower than the upper most position of the industrial robot1(when the industrial robot1is fixed horizontally as shown in this embodiment).

FIG. 5is a longitudinal sectional view showing the typical structure of the rotating unit3. The rotating unit3comprises a support part18, a drive part (equivalent to a drive source)19, a driven part20, a rotation arm (equivalent to a movable member)21, and an elevating part22. The drive part19is installed in the side of the support part18side by side, and the driven part20is supported rotatably by the support part18.

The drive part19is constituted with a drive pulley25attached to a shaft24of a rotation motor23. The driven part20is constituted with a driven pulley27fixed to the upper end of a shaft26supported rotatably by the support part18and a revolving member28fixed to the lower end of the shaft26.

The drive pulley25and the driven pulley27are connected with a drive belt29, so that the rotation motor23rotates the revolving member28. In this case, the drive part19is in a form that its head portion is located in the side of the straight axis4, and is contained in the cover member13.

The rotation arm21is fixed to the revolving member28of the driven part20. Therefore, the rotation arm21revolves so that the rotation arm21may become parallel to the longitudinal direction of the straight axis4(i.e., to the horizontal direction) with the rotation of the rotation motor23. There is provided an elevation motor30in the rotation arm21. A pinion gear31ais disposed at a tip of a shaft31of the elevation motor30.

The elevating part22is fixed at a tip of the rotation arm21. The elevating part22comprises a base member32, a main slider33and an accompanying slider34, and these components are connected each other in a so-called telescopic mechanism. A rack35is fixed to the accompanying slider34, and the pinion gear31aof the elevation motor30is engaged with the rack35.

The accompanying slider34is equipped with another rotation motor36, and a flange37rotates by the rotation motor36. The flange37is designed to equip a grasping device, which is not shown here. In the case where the grasping device equipped on the flange37is operated by compressed air, the air is supplied to the grasping device through the compressed air tubes passing inside the Cableveyor15according to a movement of a solenoid valve (not shown) for supplying the pressured air to the grasping device.

The main slider33and the accompanying slider34elevate according to the drive force of the elevation motor30. That is, in the state where the main slider33and the accompanying slider34are located in the upper most position, as shown inFIG. 6, the accompanying slider34equipped with the rack35will descend by rotating the elevation motor30. In this case, the main slider33descends together with the accompanying slider34integrately in accordance with the descending of the accompanying slider34.

As shown inFIG. 7, when the main slider33descends 100 mm, the base member32will suppress the descent of the main slider33, thus only the accompanying slider34descends. As shown inFIG. 8, when the accompanying slider34further descends 100 mm more and is located in the lower most position, the main slider33will suppress the descent of the accompanying slider34.

If the elevation motor30is rotated in the opposite direction in the state shown inFIG. 8, the accompanying slider34will elevate and at the position where the accompanying slider34touches the main slider33, the accompanying slider34and the main slider33will elevate integrately.

The above-mentioned separate motors7,23,30and36, and the solenoid valve for supplying pressured air are controlled by a robot controller (not shown).

In the industrial robot1constituted as mentioned above, the drive part19is located in the inner side of the bent portion of the Cableveyor15at the side of the straight-moving unit2.

Further, the rotating unit3is disposed offset from the axial center of the straight axis4so that the center of revolution of the rotation arm21may be located at approximately the center of the industrial robot1in its width direction.

That is, as shown inFIG. 3, since the width of the industrial robot1is set between an end surface of the straight axis4and another end surface of the box11, the center of revolution of the rotating unit3is located at approximately the center point of the straight axis4and the end surface of the box11.

Further, the Cableveyor15is arranged at a higher position than the elevating part22where the elevating part22is located in the upper most position.

Now, if the motor7(for straight-moving axes) rotates according to the instructions From the robot controller, the rotating unit3moves in the straight-line movement in accordance with the straight-line movement of the sliders6.

At this time, since the end of the Cableveyor15connected with the cable duct14of the suspension base12moves in accordance with the movement of the rotating unit3, a shape of the bent portion of the Cableveyor15changes.

Here, in the present embodiment, since the Cableveyor15is arranged so that it bends in a horizontal plane, and receives the weight of its own in the gravity direction by itself, the Cableveyor15and the maintenance member16do not collide even if the shape of the bent portion of the Cableveyor15changes as mentioned above.

According to the above-mentioned embodiment, the Cableveyor15may be able to support its own weight in the direction of gravity since the Cableveyor15having the bent portion that connects between the straight-moving unit2and the rotating unit3is arranged so that the bending direction becomes horizontal.

As a result, the Cableveyor15and the maintenance member16do not collide, thus the collision noise or the dust caused by the collision can be suppressed.

Moreover, since the Cableveyor15is arranged in the side of the straight axis4, the height size of the robot1can be suppressed compared with the composition that arranges the Cableveyor15on the upper surface of the straight axis4.

In addition, since the Cableveyor15is arranged in a lower position than the upper most position of the robot1, the Cableveyor15does not exceed the upper most position of the robot1, thus the height of the robot1is not restricted by the Cableveyor15.

Further, since the Cableveyor15does not intersect with the elevating part22when the Cableveyor15is located in the higher position than the upper most position of the elevated elevating part22, the rotating range of the rotating unit3is not restricted by the Cableveyor15.

The present invention is not limited to the revolution unit3, but the present invention can be applied to any suspended unit that is suspended on a straight axis with a straight line movement.