JPS6150784A - Multi-joint robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an industrial articulated robot, and is an improved mechanism for fixing the posture of a mounting surface for a hand, a tool, etc.

Conventional Structure and Problems Conventional articulated robots have a drive source consisting of actuators, encoders, etc. as many degrees of freedom as the articulated robot, and these are appropriately controlled to operate. Such articulated robots are extremely flexible and are effective in performing various tasks. However, in order to increase the flexibility, a higher degree of freedom is required, and therefore a large number of drive sources are also required, which has the disadvantage of increasing costs including the controller.

OBJECTS OF THE INVENTION The present invention provides an articulated robot that can reduce the number of drive sources and reduce the cost without reducing the degree of freedom for working surfaces.

Structure of the Invention The articulated robot of the present invention includes a rotation unit that is placed on a base and can freely rotate around a vertical axis, and a plurality of arms that are connected to each other on this rotation unit and each can swing around a horizontal axis. The arm unit has two degrees of freedom, and the mounting member at the tip of the arm unit for attaching the hand and tools can swing around a horizontal axis and rotate around an orthogonal axis perpendicular to the horizontal axis. The articulated robot includes a wrist unit, and inside the wrist unit there is a bevel gear fixed to the mounting member with the orthogonal axis as the center, and a horizontal axis facing the bevel gear and meshing with the bevel gear. It has a built-in differential gear mechanism consisting of two bevel gears rotatably arranged around a horizontal axis. and one bevel gear fixed to the base via a coupling mechanism so as to mesh with both of the two bevel gears, The gear ratio of the differential gear mechanism and the bevel gear train constituting the differential gear mechanism in the wrist unit is the same, and the differential gear mechanism in the swing unit has the same gear ratio.
A transmission means is provided for separately transmitting the rotation of the horizontal shaft bevel gears to the two horizontal shaft bevel gears of the wrist differential gear mechanism.

This transmission means is arranged between a plurality of rotary members each rotatably supported on a horizontal shaft serving as a pivot center of each arm of the arm unit and the rotary members at both ends of each arm (11).
It consists of a parallel link mechanism consisting of a transmission member and a transmission member.

In this way, in order to transmit the rotational output from the differential gear mechanism in the swing unit including the bevel gear fixed to the base to the differential dual-arm mechanism configured in the wrist unit by a two-path parallel link mechanism, Further, since the tooth ratios of the bevel gears constituting these two differential gear mechanisms are the same, the posture and direction of the wrist unit or the mounting member are always constant regardless of the operation of the arm unit and the swing unit. Therefore, there is no need for a drive source to drive the wrist unit, and it is possible to create a multi-jointed robot with multiple degrees of freedom, good controllability, and a low level of control. Since the transmission path can be temporarily separated, the wrist posture can be set as desired, making it suitable for more tasks.

As described above, since it has multiple degrees of freedom, there is sufficient flexibility regarding the position, and since the wrist posture is kept constant, the number of driving sources can be reduced. Therefore, low-cost articulated robots can be provided for specific tasks.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention is shown in FIGS. 1 to 4. 1st
Figure (a) shows an overall sectional view of the multi-jointed robot throat of this embodiment, and Figure 1 (bl shows a side view).

In FIG. 1, a swing unit 2 is provided on a base 1 and is swingable around a vertical axis A. As shown in FIG. An upper arm 3 that swings around a horizontal axis B is connected to the end of the swing unit 2, and a front arm 1i 4 that swings around a horizontal axis C is connected to the upper arm 3, and the upper arm 3 and forearm 4 form an arm unit 5. It consists of At the tip of the forearm 4 is a wrist unit 62 that swings around a horizontal axis and is rotatable around an orthogonal axis E that is orthogonal to the horizontal axis.
is set up. Inside the wrist unit 6 are a mounting member 7 for attaching a handshake and a tool, a fixed beveled float 8, and a pair of bevel gears 8 that are rotatably supported around a horizontal axis and arranged to mesh with each other. A bevel gear 9.10 is built in, and the bevel gears 8.9.10 form a differential gear mechanism 11. Pulleys 12, 13 are fixed to the bevel gear 9.10.

There is a joint shaft 14 fixed to the forearm 4 on the horizontal axis C, and a pulley 15 is fixed to the joint shaft 14, and a pulley 17 and a pulley 19 are rotatably supported with the pulley 15 in between. Pulley 17 is connected to pulley 16, and pulley 19 is connected to pulley 18. Pulley 12.1
3. IG and 18 all have the same diameter. Pulley 12.16 is wrapped around a belt 20, and pulley 13.18 is similarly wrapped around a heald 21. On the horizontal axis B, there is a rotating unit 2 and a rotary unit 1lIiy which is rotatable and fixed to the upper arm 3! There is 1lI22. Pulley 23 is joint axis 2
2 and is connected to a motor 24 and a belt 25. The pulley 26 is connected to the boo IJ 27 and rotatably supported by the joint shaft 22, and the motor 28 and the pulley 27 and the pulleys 26 and 15 are connected by healds 29 and 30, respectively. Further, a pulley 32 and a pulley 34, which are rotatably supported by the joint shaft 22, are arranged with a pulley 26 in between. Pulley 32 is connected to pulley 31. Pulley 34 is connected to pulley 33. Pulley 171
2゜19.34 are all the same diameter, pulley 17 and boo 1
J32, pulley 19, and pulley 34 are wrapped around belts 35 and 36, respectively.

A shaft 37 parallel to the joint shaft 22 is fixed within the rotation unit 2. The joint shaft 37 has a boo IJ39 connected to a bevel gear 38 and a boo IJ4 connected to a bevel gear 40.
1 is rotatably supported.

Also, on the vertical axis A is a connecting mechanism 4 fixed to the base l.
A bevel gear 43 is installed to mesh with the bevel gear 38 and the bevel gear 40 via the bevel gear 2, and the bevel gears 38, 40, and 43 constitute a differential gear mechanism 44. The ratio of the number of teeth of the beveled wheels constituting the differential gear machine (1) l and the differential gear mechanism 44 is the same. The bevel gear 43 is vertically slidable on a bracket 45 that constitutes the coupling mechanism 42 and is fixed to the bracket 45 via a pin 46 . In addition, the bevel gear 43 is a bevel gear 38°40
The length of tM fll is sufficient to release the mesh with the tM fll.

The pulleys 31, 39, and 33.41 all have the same diameter, and the windings of the pulleys 31.39 and 33.41 are conducted by a heel) 47.48, respectively. Further, there is a gear 49 on the outer periphery of the swing unit 2, which meshes with an output gear 51 of a motor 50 fixed to the base l. Also,
A position detector (not shown) such as an encoder is attached to each motor 24.28.50.

The operation of the articulated robot configured as described above will be explained below. The rotating units 1 and 2 are output gears 51. S'f=)J is carried out by the motor 5() via the gear 49. The upper arm 3 is driven by a motor 24 via a heald 25, a pulley 23, and a joint shaft 22. Further, the forearm 4 is moved by a motor 28 to a heald 29 and a pulley 27.2.
6. Driven via belt 30, pulley 15, and joint shaft 14. The arm unit 5 and the swing unit 2 are driven by the above three motors, and the position of the zero point (FIG. 2) at the tip of the arm unit 5 is arbitrarily determined.

Next, the relationship between the arm unit 5 and wrist unit 6 will be explained. As shown in Fig. 2, the arm unit 5 is
, G, H, even if the pulley 32,1? and belt 35 form a parallel link, pulley 16.12 and heald 20 also form a parallel link, and pulley 16.17 is connected. A similar relationship is maintained between the pulleys 34 and 18, the belt 36 and the pulley 18, 13 and belt 21. Therefore, the wrist unit 6 remains in its initial state (facing downward in FIG. 2). Further, the rotation of the boob generated by the DJ operation of the arm unit 5 is transmitted to the final bevel gears 9 and 10, and attempts to rotate the bevel gears 8 in opposite directions. Therefore, if only the arm unit 5 moves, no rotational movement occurs in the mounting member 7.

Next, rotation of the mounting member 7 will be explained. When the swing unit 2 swings, since the bevel gear 43 is fixed to the base l via the coupling mechanism 42, the bevel gear 38.
40 causes a drift and rotates in opposite directions. This rotation is caused by the pulleys that constitute different transmission paths,
It is transmitted to the bevel gear 8 via the belt. Since the tooth ratios of the bevel gears constituting the differential gear mechanism 42 and the differential gear mechanism 11 or the diameters of the pulleys constituting the intermediate transmission path are the same, the rotation of the swing unit 2 is completely rotated in the opposite direction to the mounting member 7. It will be transmitted to Therefore, as shown in FIG. 3, the relationship between the X and Y axes set on the base 1 is maintained in the same manner on the mounting member 7 even when the swing unit 2 rotates.

Next, the initial setting of the wrist posture will be explained. As shown in FIG. 4, in the coupling mechanism 42, the bevel gear 43 is slid downward to release the mesh with the bevel gears 38 and 40 (in the direction of arrow Q in the figure). At this time, the differential gear mechanism 11 in the wrist unit 6 and the differential gear mechanism 4 in the swing unit 2
2, since the communication is cut off, the wrist unit and toro can freely rotate around the horizontal axis, and the mounting member 7 can freely rotate around the orthogonal axis E, regardless of the position and posture of the arm unit 5 and the rotation unit 2. (Arrows M and N in the figure). After determining the wrist posture according to the working style, the bevel gear 43 is again engaged with the bevel gears 38 and 40, and the wrist unit 6 and the mounting member 7 are fixed.

In addition, in the above embodiment, two differential gear mechanisms 11.4
Although a heald and a pulley are used to transmit rotation between the two, it goes without saying that a chain and a sprocket may also be used, as long as they can reliably transmit rotation. It goes without saying that the parallel link made up of pulleys and belts can also be made up of link bars. Further, although the coupling mechanism 42 is disposed within the swing unit 2, it goes without saying that it may be disposed within the wrist unit 6 or within the arm unit 5.

In this way, this articulated robot has a differential gear mechanism 4 in the rotation unit 2 that includes a bevel gear fixed to the base 1.
The rotational output from 4 is made up of a 2-path parallel link mechanism in the wrist unit 6.
and these two differential gear mechanisms 11.
Since the gear ratios of the bevel gears 44 are the same, the posture and direction of the wrist unit 6 or the mounting member 7 are always constant regardless of the operations of the arm unit 5 and the swing unit 2. Therefore, a drive source for driving the wrist unit 6 is not required, and although the robot has multiple degrees of freedom in general, it has good controllability and can be made into a low-cost articulated robot. At the same time, two differential gear mechanisms 11.44
Since the transmission path can be temporarily interrupted, the wrist posture can be set arbitrarily, and it has great practical effects, such as being able to be used for more tasks.

Effects of the Invention The articulated robot of the present invention has multiple degrees of freedom, has sufficient flexibility regarding position, and has a structure that keeps the force of the hand II' V5 constant, so it is possible to reduce the driving source, and it is possible to The effect is that the cost can be lowered without the problem of functional deterioration.

[Brief explanation of the drawing]

FIG. 1(a) is an overall sectional view of an articulated robot according to an embodiment of the present invention, FIG. 1(b) is a side view thereof, FIG. 2 is a side view similarly showing its operating state, and FIG. Similarly, FIG. 4, which is a bottom view, is an explanatory diagram of the wrist posture setting method. DESCRIPTION OF SYMBOLS 1...Base, 2...Swivel unit, 3...Upper arm, 4...Forearm, 6...Wrist unit, 7...Mounting member, 11°44...Differential gear mechanism, 42...Connection mechanism (a) Figure 1 Figure 3 Figure 4

Claims (2)

[Claims] (1) A swing unit that is installed on a base and can freely rotate around a vertical axis, an arm unit that is installed on this swing unit and is connected to a plurality of arms that can each swing around a horizontal axis, and this arm unit It consists of a two-degree-of-freedom wrist unit in which the mounting member provided at the tip to which the hand and tools are attached is swingable around a horizontal axis and rotatable around an orthogonal axis perpendicular to the horizontal axis.
Inside the wrist unit, there are a bevel gear fixed to the mounting member around the orthogonal axis, and two bevel gears facing each other so as to be rotatable around the horizontal axis so as to mesh with the bevel gear. Built-in differential gear mechanism consisting of
Inside the swing unit, two umbrellas are disposed facing each other and are rotatable about a horizontal axis that is within a plane that includes a horizontal axis that is a swing axis of the arm at the base end of the arm unit. It has a built-in differential gear mechanism consisting of a gear and one bevel gear fixed to the base via a coupling mechanism so as to mesh with both of the two bevel gears, and The gear ratios of the bevel gear trains constituting the dynamic gear mechanism and the differential gear mechanism in the wrist unit are the same, and the rotation of the two horizontal axis bevel gears of the differential gear mechanism in the swing unit is controlled separately from the wrist. A transmission means is provided for transmitting transmission to the two horizontal shaft bevel gears of the differential gear mechanism, and this transmission means includes a plurality of shafts each rotatably supported on a horizontal shaft serving as a rocking center of each arm of the arm unit. This multi-jointed robot consists of a parallel link mechanism consisting of a rotating member and a transmission member suspended between the rotating members at both ends of each arm. (2) A patent in which one bevel gear fixed to the base constituting the differential gear mechanism built into the swing unit can be freely disengaged from the other two bevel gears by a coupling mechanism. An articulated robot according to claim (1).