DE3513056A1 - JOINT DRIVE ARRANGEMENT - Google Patents

Description

HOEGER, STEbLi ^ EGnT-A ^ A-RTNER 3513

PATENTANWÄLTE UHLANDSTRASSE 14 cD 7OOO STUTTGART 1

A 46 575 b Applicant: GCA Corporation k - 176 209 Burlington Road

April 10, 1985 Bedford, Mass. 01730

UNITED STATES.

Articulated drive arrangement

The invention relates to an articulated drive arrangement for a work machine (robot). In particular deals the invention with a three-axis joint drive assembly which is specifically for use in conjunction with a vertical, telescopic pipe arrangement is suitable, which is from a above the Work area movable carriage is carried. Such an arrangement is in a further application by the applicant (U.S. Patent Application Serial No. 439,601).

According to the earlier application, the carriage carries a conventional three-axis joint, with the drive being rotated each of the axes is done independently with the help of its own motor and the motor axes are essentially run along the drive axles. With this construction, the motor can be used for rotary drive around the vertical Axis can be conveniently mounted in the telescopic tube arrangement. The motor for swiveling the working element protrudes from the side of the arrangement and thus limits their pivoting possibilities for certain

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Applications to some extent. The motor for rotating the working organ itself is according to the above Application arranged in an arm of considerable length / which extends from the joint, so that the Working organ is located at a corresponding distance from the point of intersection of the three joint axes.

Based on the constructions described above, the object of the invention is to provide a specify improved three-axis joint drive arrangement for an automatic machine or a robot, in which the working organ or a tool is attached close to the intersection of the three joint axes can.

This object is achieved according to the invention by an articulated drive arrangement solved with the features of claim 1.

In the case of the articulated drive arrangement according to the invention, the working organ, which from the mounting devices is carried, thereby pivoted or pivoted about the output shaft of the differential gear devices. be rotated that one lets the two elongated motor assemblies run with opposite directions of rotation. In addition, the working element can be pivoted together with the gear housing about the aligned axes of the input elements by adjusting the elongated

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Motor assemblies drives in the same direction of rotation. Furthermore, the working organ can by actuating the Rotary drive are rotated about the axis of the tubular mounting element.

It is an advantage of the articulated drive arrangement according to the invention, that it can be made extremely compact, so that the working organ of all Sides can be brought close to a workpiece, especially if the tubular mounting element comprises a telescopic tube assembly. Another advantage of the articulated drive arrangement according to the invention is that the control of the pivoting and rotating movements is facilitated by the fact that all three joint axes intersect at a common point of intersection. Furthermore, the working body can the joint drive arrangement according to the invention can be rotated freely about its axis of rotation. Here is the articulated drive arrangement very reliable and also suitable for heavy work organs and tools. Still is the articulated drive arrangement according to the invention has a relatively simple structure and can therefore be manufactured inexpensively.

Further details and advantages of the invention are explained in more detail below with reference to drawings. Show it:

1 shows a perspective crane support structure with a three-axis joint drive arrangement according to the invention;

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Figure 2 is a front view of the articulated drive assembly ;

Figure 3 is a side view of the articulated drive assembly ;

4 shows a partial longitudinal section through the articulated drive arrangement the line 4-4 in Figure 3;

Figure 5 is a cross-sectional view taken along line 5-5 in Figure 2;

6 shows a partial cross-section in parallel to the line 4-4 in Fig. 3 to illustrate the structure of a differential gear arrangement of Articulated drive assembly according to the invention .

In detail, Fig. 1 shows a support structure or a frame 11 with two rails 13, of which in Fig. 1 only one is visible. A bridge arrangement can be moved along the rails 13 and in turn carries it a carriage 19 / on which one in the vertical direction telescopic tube assembly 23 is supported. At the lower end of the telescopic tube assembly is a three axis joint 24 according to the invention

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assembled. A working element or a tool 25 is mounted on the joint 24.

The operation of the bridge device 1 I ₁ of the carriage and the telescopic tube assembly 23 is described in detail in the aforementioned application. For the present application, it should be sufficient to point out that the movements of the assemblies mentioned along the three mutually perpendicular axes are controlled by a servomotor system. Typically, each of the servo loops comprises a DC servo motor for generating the drive force and an independent scanning system, for example an angle encoder or a section with markings for separately determining the actual movement along the relevant axis. It is an advantage of crane scaffolding robots of the type under consideration that they can work relatively uniformly in a large space or in a large volume which can be easily changed and expanded. Since the axes of movement are perpendicular to one another, a manipulator of the type under consideration can also be programmed relatively easily. For the successful use of such manipulators, it is important that a joint arrangement is provided at the lower end of the telescopic tube arrangement 23, which allows the working member to be rotated or pivoted, preferably about three axes that intersect perpendicularly to one another,

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so that complete flexibility in the positioning of the working organ can be achieved.

As FIG. 2 shows, the three-axis joint 24 shown as an exemplary embodiment comprises a mounting plate 27 for mounting the joint 24 on the floor (at the lower end) of the pipe arrangement 23. Below the mounting plate 27 is a tubular housing 29, which is essentially an extension of the last Tube of the tube assembly 23 forms. In the housing 29 there is a rotary drive, which is below will be explained in more detail and which serves a base element 33 around the (vertical) axis of the telescopic Pivot tube assembly 23.

The base member 33 carries two elongated motor assemblies 35 and 37 which are vertical and parallel to the Housing 29 and the rotary drive located therein are mounted tightly on the housing 29. Any of the engine assemblies 35,37 drives a right-angled bevel gear 41 or 43, the output shaft of which with the shaft of the assigned motor encloses an angle of 90 °. Between the bevel gears 41,43 is a Gear housing 45 with a differential gear system 47 is arranged. The differential gear system 47 has two aligned but opposing input elements or shafts, each of which by the respectively assigned bevel gear 41

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or 43 is driven. The differential gear system 47 also has an output shaft which carries a mounting plate 49 on which a working element can be mounted. Any of the above Sub-arrangements, the mutual position of which is also clear from FIG. 3, will be referred to below explained in more detail on corresponding drawing figures.

Fig. 4 shows that the tubular housing 29 has an inner tube 51 which is rigid with the mounting plate 27 is connected, as well as an outer tube 53, which by means of bearings 54 and 55 rotatably on the inner tube 51 is mounted. An elongated DC servo motor 56 is mounted in the inner tube 51 and has an output shaft, which is the input shaft of a (harmonic) reduction gear 57 drives. The reduction gear 57 in turn drives the outer tube 53 via its output shaft 58, which, like the outer tube 53, also drives it the mounting plate 49 is connected. Furthermore, a servo rotary encoder 59 is provided, which directly detects the angular position of the output shaft 58 and supplies a feedback signal which is used to control the Feeding the servo motor 56 is used, so that a dead gear and incorrect positioning of the mechanical Mounting system can be adjusted. The advantages of such a feedback system are detailed

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described in the application mentioned at the beginning.

The motor assembly 35 is shown in greater detail in FIG. It is understood that the motor arrangement 35 is formed essentially in the same way as the motor assembly 37, which, however, is based on the opposite side of the mounting plate 33 is mounted and are therefore not described in detail target.

Like the rotary drive for the vertical axis, each of the two motor assemblies 35, 37 comprises an elongated one DC servo motor 61, which drives an associated (harmonic) reduction gear 62. Each Motor 61 with its reduction gear 62 is assigned a right-angled bevel gear, preferably a gearbox with hypoid gearing and an output shaft offset from the drive shaft. The output shaft 63 of the reduction gear 62 drives the smaller of the bevel gears, i.e. the pinion 64. The The larger bevel gear or the toothed ring 65 drives an output shaft 66. The two essentially identical motor arrangements 35, 37 are mounted on opposite sides of the mounting plate or the base element 33 and oriented so that the output shafts 66 are aligned but in opposite directions so that they mate with the drive shafts of the differential gear system 47. The actual

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The angular position of the output shafts 66 is recorded in each case by a servo rotary encoder 67, which a feedback signal generated by the Control for regulating the drive energy for the assigned DC servomotor 61 evaluated can be. The differential gear system 47 with its two drive shafts 71 and 72 is shown in FIG shown. The drive shafts 71, 72 are in a differential gear housing 45 mounted and connected to associated bevel gears 73 and 74, respectively. In the case 45 an output shaft 75 is also mounted, which runs perpendicular to the drive shafts 71 and 72. The output shaft 75 carries a bevel gear 76 which meshes with the two bevel gears 73 and 74. The other The end of the output shaft 75 carries the above-mentioned mounting plate 49.

As is clear from FIG. 6, the differential gear housing 45 is arranged in a floating manner and is not fastened to the base element 33, but is only supported by the two drive shafts 71 and 72. When the drive shafts 71 and 72 are driven in opposite directions of rotation, the output shaft 75 consequently rotates about its axis and pivots the working element 25 about the longitudinal axis of the output shaft 75 ( ff axis). If, however, the two drive shafts 71 and 72 rotate in the same direction of rotation, then the output shaft 75 rotates together with the

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Housing 75 and the working element 25 around the common Axis of the drive shafts 71/72.

From the above description it is clear that none of the motor arrangements 35 or 37 the rotary movement about one or the other of the two axes of rotation mentioned controls independently. Instead, there is the Drehbzw. Swivel movement of the work process as a function of the direction of rotation and the speed of both motors. While this link is responsible for the tasks of the On the other hand, it should be noted that the combination of movements is only makes it necessary to simply add the position signals generated by the rotary encoders which are assigned to the engine assemblies. This is in contrast to the complicated geometrical relationships that exist in other robot systems can occur in which the axes of rotation are not perpendicular to each other or do not intersect.

An important advantage of the differential drive according to the invention is that the various elongated motor assemblies are close to the vertical tube assembly and can be mounted parallel to this and that the working organ is very close to the point of intersection the three axles can be mounted so that no weighty arm length is required to accommodate to create for the motor that drives the working element around the third axis.

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In view of the foregoing it is clear that the invention on which the invention is based Object is achieved and that a number of other advantages can be realized.

In addition, it is clear from the above description that the person skilled in the art, on the basis of what has been described Embodiment, numerous possibilities for changes and / or additions are available without bids that he would have to leave the basic idea of the invention.

Claims (7)

Claims 1. Articulated drive arrangement for an automatic machine (Robot), characterized by the following features: an elongated / tubular mounting element (23,27,29) is provided; a base element (33) is provided; rotary drive devices (56,57,58) are provided, which are aligned with the tubular mounting element (23,27,29) and through the the base element (33) for a rotary movement about the axis of the tubular mounting element (23,27,29) is drivable; two elongated motor assemblies (35,37) are provided which are adjacent to the base element (33) mounted on and parallel to the tubular mounting element (23,27,29); a gear housing (45) is provided in which differential gear devices (71 to 76) are rotatable are mounted, which two input elements (71,72) comprise, which are aligned to each other, opposing axes are rotatable and each of which is in driving connection with the -2- A 46 575 b k - 176 - 2 - April 10, 1985 each associated elongated motor assembly (35/37) is, and which also has a drive shaft (75) extending perpendicular to the input members (71,72); and Mounting devices (49) for mounting a working element (25) are provided on the output shaft (75). 2. Articulated drive arrangement according to claim 1, characterized characterized in that the axis of the tubular mounting element (23,27,29) and the axes of the input elements (71,72) of the differential gear devices (71 to 76) and the axis of the output shaft (75) of the same all on a common Cut intersection. 3. Articulated drive assembly according to claim 1, characterized in that each of the motor assemblies (35, 37) a direct current motor (61), a harmonic reduction gear (62) for reducing the speed of the motor (61) and a right-angled bevel gear (41,43) with a to the output shaft of the Motor (61) includes vertical output shaft (66). 4. Articulated drive arrangement according to claim 3, characterized characterized in that each of the elongate motor assemblies (35,37) each have a rotary encoder (67) for generating a feedback signal -3- A 46 575 b k - 176 - 3 - April 10, 1985 is assigned which is the angular position of the relevant input element (71/72) of the differential gear devices (71 to 76). 5. Articulated drive arrangement according to claim 1, characterized characterized in that the tubular mounting element comprises a telescopic tube assembly (23). 6. Articulated drive arrangement according to claim 3, characterized characterized in that the gear housing (45) is arranged between the bevel gears (41, 43) and that the input elements (71,72) of the differential gear devices (71 to 76) each with the output shaft of the associated bevel gear (41, 43) are connected. 7. joint drive arrangement according to claim 3, characterized in that the bevel gears (64,65) of the Bevel gears (41, 43) have a hypoid toothing and are laterally offset from one another Axes are rotatable. -4-