JPH028714Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to the improvement of an industrial robot that has a plurality of arms that are telescopically extendable. This invention relates to an industrial robot designed to do the following.

[Conventional technology]

Industrial robots that have multiple arms that are telescopically extendable and retractable can be operated with the multiple arms contracted except when moving a workpiece to a predetermined position. This allows the robot to be installed in a narrow space or relatively close to peripheral devices without causing any interference.

FIG. 1 is a partially sectional side view of a telescopic arm industrial robot. In Fig. 1, 1 is the base of the robot, 2 is the lifting shaft supported by the base 1, 3 is the arm support, and the lifting shaft 2
is pivotably supported on the top. 4 is a first arm, and 5 is a second arm. A square pipe-shaped first arm 4 is supported by the arm support 3 so as to be movable forward and backward. 6 is a motor that is a driving source for the first arm 4;
7 is a speed reducer, both of which are attached to the arm support 3. 8 is a ball screw nut fixed to the first arm 4; 9 is screwed to the nut 8, and is connected to the reducer 7;
This is the screw shaft of a ball screw that is rotated by. The second arm 5 is supported by the first arm 4 so that it can move in and out. That is, the second arm 5
Guide rails 10 are provided in the longitudinal direction on the upper and lower surfaces of the arm 4, and guides 11 that engage with these guide rails 10 are provided on the inner tip side of the first arm 4 in the front and rear. Further, partition walls 12 and 13 are provided inside the first arm 4 and the second arm 5, respectively, and the partition wall 12 is equipped with a second motor 15 and a second reduction gear 16 for driving the second ball screw 14. Attachment: A second ball screw nut 17 that is screwed into the second ball screw 14 is attached to the partition wall 13.

Therefore, the first arm 4 moves forward or backward horizontally by rotating the ball screw 9. The second arm 5 projects from the first arm 4 or enters into the first arm 4 by rotating the second ball screw 14. That is, the second
The arm 5 telescopically extends and retracts relative to the first arm 4.

[Problem that the invention attempts to solve]

Conventional industrial robots with telescopic arms, such as those mentioned above, require the same number of drive sources, such as motors, as there are arms, which requires multiple motor control devices, making it difficult to accurately control the arm length. There was a problem.

As a structure to improve this, there is a structure in which the core arm is moved forward or backward using a single feed screw, as disclosed in Japanese Utility Model Application Publication No. 58-80195.

However, although this structure only requires one motor,
Since the core arm is moved forward or backward using a single feed screw, the feed screw becomes long, its rigidity decreases, vibrations are likely to occur during rotation, and high-speed extension and contraction of the arm is difficult.

Furthermore, there is a device that uses a single drive source (motor) as disclosed in Japanese Patent Application Laid-Open No. 167390/1982 and that telescopically extends and contracts the arm by driving a plurality of ball screws in conjunction with a speed reduction mechanism.

However, in order to rotate the second stage screw shaft, this structure relies on the rotation of the drive source using gears, spline shafts, etc.
It is communicating with gear. Therefore, play in the splines that slide while transmitting rotational force becomes a problem.
Therefore, devices such as robots that require high position repeatability require high position repeatability when the tip of the arm is repeatedly moved to an arbitrary point, such as a robot. However, it has the problem that it is not suitable for other types of equipment.

This idea was made to solve the above problems, and by driving multiple arms that extend and retract in a telescopic manner with one drive source, the control device for the drive source is reduced to one, and furthermore. ,
By providing each arm with a screw shaft and nut for expansion and contraction, and driving these simultaneously and directly from the drive source, the length of the arm can be precisely controlled.
The purpose of the present invention is to provide an industrial robot that can extend and retract its arm at high speed.

[Means for solving problems]

The industrial robot according to this invention includes a first arm that is slidably supported by the arm support attached to the robot body and has a movable body fixed to the base side; a first screw shaft that is fixed to the arm support parallel to the arm and has an effective length equal to the stroke of the first arm; a first nut supported by the first arm, a second arm slidably disposed inside the first arm, and one nut disposed inside the second arm, one of which is slidably disposed inside the second arm a second threaded shaft that is freely and rotatably supported, the other end is rotatably supported by the movable body, and has an effective length equal to the stroke of the second arm, and is fixed to the base side of the second arm; a second nut screwed onto the second screw shaft and prevented from rotating; , the second screw shaft is also provided with a driving force transmission device that directly transmits the driving force, and further the strokes of the first arm and the second arm are the same,
The driving amount of the first arm and the second arm by the driving force transmission device is the same, and the second arm expands and contracts with respect to the first arm.

[Effect]

In this invention, the first arm and the second arm are each provided with a screw shaft and a nut for telescopic operation, and because these are driven simultaneously and directly from the drive source, no backlash occurs when the arms extend and retract. Furthermore, since the strokes of the first arm and the second arm are the same, and the amount of drive is the same, and the second arm extends and contracts with respect to the first arm, the moving speed of the tip of the arm can be increased.

[Example of idea]

An embodiment of this invention will be described below based on the drawings.

FIG. 2 is a side view showing an embodiment of this invention, FIG. 3 is an enlarged sectional view of the main part of this invention, and FIG. 4 is a sectional view taken along the line -- in FIG.

In FIGS. 2 to 4, 1 is a robot base, and 20 is a main shaft, which is supported perpendicularly to the base so as to be rotatable. A boom 21 serves as an arm support, and is supported vertically and movably at a right angle to the main shaft 20. Rotation of main shaft 20 and boom 21
The vertical movement of is performed by a well-known mechanism and drive source.

The boom 21 is composed of a box-shaped outer frame and ribs that support various mechanisms housed inside. At one end 21a in the longitudinal direction of the boom 21, a first
Two bearings 22 that slidably support the arm 4a are fixed. The other end of this bearing 22 is a rib 21
It is supported by b.

5a is a second arm slidably disposed inside the first arm 4a, and 5b is two second arms 5a.
A hand device (not shown) is attached to the connecting member that connects the tips of the two. 4b is the two first arms 4
23 is a moving body fixed to the end of the first arm 4a on the inside of the boom 21, that is, the base side; 9a is a first ball screw With the screw shaft of
It is arranged parallel to the first arm 4a, and has one end fixed to the rib 21b and the other end fixed to the other longitudinal end 21c of the boom 21.

The screw shaft 9a of this first ball screw has an effective length equal to the expansion/contraction stroke of the first arm 4a. Note that the length of the first screw shaft 9a needs to be at least the same length as the stroke of the first arm 4a, and in reality it will be longer than the stroke taking into consideration installation etc., so here it is referred to as the effective length. I will use words.

Reference numeral 14a denotes a screw shaft of a second ball screw, which is disposed inside the first arm 4a and the second arm 5a, one end of which is slidably and rotatably supported inside the arm 5a, and the other end of which is rotatably supported by the moving body 23. freely supported. The screw shaft 14a of this second ball screw
has an effective length equal to the extension/contraction stroke of the second arm 5a. 17a is a nut screwed onto the screw shaft 14a of the second ball screw, and is fixed to the end of the second arm 5a. Note that the sliding mechanisms between the bearing 22 and the first arm 4a and between the first arm 4a and the second arm 5a are well known.

24 is a motor which is a drive source fixed to the movable body 23, and 8a is a nut for the first ball screw which is screwed onto the screw shaft 9a of the first ball screw and rotatably supported by the movable body 23. 25 is a gear fixed to the shaft of the motor 24, 26 is a gear fixed to the screw shaft 14a of the second ball screw, 27 is an intermediate gear meshing with the gears 25 and 26, and 28 is a gear fixed to the nut 8a. . Gears 25, 26, 27, and 28 constitute a speed reducer 29.

Note that the speed reducer 29 is connected to the motor 2 which is the drive source.
It operates as a driving force transmitting device that transmits the driving force (rotational force) from 4 to the first nut 8a, and at the same time directly transmits the driving force to the second screw shaft 14a.

Further, the strokes of the first arm 4a and the second arm 5a are the same, the amount of drive of the first arm 4a and the second arm 5a by the driving force transmission device is the same, and the second arm 5a is the same as the first arm 4a. Expand and contract based on . Here, the driving amount being the same means that, for example, if the first arm 4a extends by 10 cm, the second arm 5a will extend by 10 cm with respect to the first arm 4a.

In the above configuration, when the motor 24 rotates, the screw shaft 14a and the nut 8
a rotates. According to this rotation, the first arm 4a assembled integrally with the movable body 23 moves to the left in FIG. 3, and at the same time, the second arm 5a also extends to the left from inside the first arm 4a. Second
The solid line in the figure shows the state in which the first arm 4a and the second arm 5a are fully extended, and the one-dot chain line shows the state in which the arm is fully retracted by reversing the rotation of the motor. Note that this state is shown with the boom raised for clarity.

In addition, according to the above embodiment, each screw shaft 9a, 1
The effective length of 4a may be 1/2 of the total stroke of the arm (the total stroke of the first arm and the second arm), and high rigidity can be maintained. Furthermore, the respective expansion and contraction speeds of the first arm 4a and the second arm 5a are different from those of the conventional example (Utility Model No. 58-58).
The speed is 1/2 of that of the core arm (No. 80195), and the speed is the same at the arm tip. That is, the above embodiment is suitable for increasing the speed of extension and contraction of the arm.

Further, since it does not have a spline that slides while transmitting rotational force unlike the conventional example (Japanese Patent Application Laid-open No. 167390/1982), no looseness occurs in the rotational force transmission system. Therefore, the repeatability of the arm position becomes highly accurate.

Further, in the above embodiment, the first arm 4a and the second arm 5a have a cylindrical shape, but the shape is not limited to a cylindrical shape, but may be a rectangular cylindrical shape. Also, each arm has two arms, and the other arm has the function of stopping the rotation of the second ball screw nut 17a, but if a rotation stopping mechanism is provided between the first arm 4a and the second arm 5a, one
It can be a book.

[Effects of the invention] As described above, according to this invention, in an industrial robot in which a plurality of arms are telescopically extendable, each of the plurality of arms is provided with a screw shaft and a nut for telescopic operation, and these are connected to one Since the robot arm is driven simultaneously and directly by multiple drive sources, the arm length can be controlled with high precision, and particularly high position repeatability can be obtained.In other words, the tip of the robot arm can be moved repeatedly to any given point. The position reproduction accuracy is high, and since the strokes and drive amounts of the first and second arms are the same, and the second arm extends and contracts with respect to the first arm, the arm can extend and contract at high speed. It is possible to obtain an industrial robot that is capable of

[Brief explanation of the drawing]

Fig. 1 is a partially sectional side view showing a conventional industrial robot with a telescopic arm, Fig. 2 is a side view showing an embodiment of this invention, and Fig. 3 is a summary of an embodiment of this invention. FIG. 4 is a cross-sectional view taken along the - line in FIG. 3. In the figure, 1 is the base of the robot, 2 is the lifting shaft, 3 is the arm support, 4, 4a are the first arms, 5, 5a
is the second arm, 6 is the motor, 7 is the reducer, 8, 8
a is the nut for the first ball screw, 9, 9a is the screw shaft of the first ball screw, 14, 14a is the screw rod of the second ball screw, 15 is the second motor, 16 is the second reducer, 17, 17a is the second ball screw nut, 2
0 is a main shaft, 21 is a boom, 22 is a bearing, 23 is a moving body, 24 is a motor, 25, 26, 27, 28 are gears, and 29 is a reduction gear. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) In an industrial robot equipped with a plurality of arms telescopically extendable and retractable as the arm to which a hand device is attached to the tip, the arm provided on the robot body a first arm that is slidably supported by the arm support and has a movable body fixed to the base side; and a first arm that is fixed to the arm support in parallel to the first arm; a first threaded shaft having an effective length equal to the stroke of the first threaded shaft;
a first nut screwed onto the screw shaft and rotatably supported by the movable body; a second arm slidably disposed inside the first arm; disposed inside the arm, one end is slidably and rotatably supported within the second arm, the other end is rotatably supported by the movable body, and further has an effective length equal to the stroke of the second arm. a second screw shaft having;
fixed to the root side of the second arm;
a second nut that is screwed onto the screw shaft and whose rotation is prevented; and a second nut that is provided on the movable body and transmits the driving force from the drive source to the first nut; The shaft is also provided with a driving force transmission device that directly transmits the driving force,
Further, the strokes of the first arm and the second arm are the same, the amount of drive of the first arm and the second arm by the driving force transmission device is the same, and the second arm expands and contracts with respect to the first arm. An industrial robot that is characterized by (2) The industry according to claim 1 of the utility model registration claim, characterized in that the first screw shaft and the second screw shaft are screw shafts of a ball screw, and the first nut and the second nut are nuts for a ball screw. Robots for use.