Manipulator gear head.

DESCRIPTION

The invention concerns a transmission head for manipulators with the characteristics indicated in the precharacterizing clause of claim 1.

From DE-AS 27 45 932 it is known to carry out a transmission head for a manipulator with two parts placed one behind the other, the two parts of the head being rotatably supported next to each other along a plane inclined. The tool holder was placed at the back of the head along a coaxial axis with respect to the drive shaft.

This base position in the extended situation of the transmission head causes difficulties in the movement of the numerically controlled manipulator. A rotation of the tool around its own axis of rotation (axis 6) preset by the program leaves the opening of the numerical prefixing concretely open if the transmission head has to rotate around the axis of the concentric drive trees (axis 4 ) or if only the back of the head has to revolve around this axis. This ambiguity has negative effects especially in the case of linear control (CP = coninous path) and so far it has only been avoided through technical program and control manipulations, although unsatisfactory.

In the case of PTP control (point-to-point control), the coaxial arrangement of the axis of rotation of the tool holder (axis 6) with respect to the concentric drive shafts is, however, little problematic.

In DE-OS 34 28 748 a transmission head is described for a manipulator formed by three parts placed one behind the other, whose central head part has two inclined axes of rotation which in the extended position of the transmission head form in each case, with the longitudinal axis of the transmission head, an acute angle opens in the opposite direction. At the end of each transmission train leading to the head parts, a strongly reducing gear is located in each case.

With such a configuration, the transmission head obtains a considerably increased movement space with a more compact construction of the transmission head, since as a consequence of the inclined turning capacity of the back of the head relative to the centrally, a significantly increased tool actuation range is achieved. Because in this known case the force output amber is not coaxial with respect to the drive shaft, ambiguities in the numerical control are avoided.

The invention seeks to solve the problem of broadening the action zone and the possibility of applying the transmission head and especially allowing the rotation of the tool holder inside the back of the transmission head without having to turn the front of the head around its axis.

This problem is solved, starting from the DEOS 34 28 748, with the distinctive characteristics of the main revindication.

The invention encompasses the basic idea of, with three drive trees placed concentrically between each other, to be able to perform four different movements of rotation in the transmission head according to the invention, namely the rotation of the front part of the head around the axis of the trees drive, the rotation of the central part of the head around the first inclined axis with respect to the front part of the head, the rotation of the back of the head around the second inclined axis with respect to the central part of the head and the rotation of the dento tool holder of the back of the head. In parallel, the invention indicates joining together by means of conical hollow axle wheelsets that extend along the two inclined axes and driving them by means of a single drive motor. Because these hollow trees are supported on the front or central part of the head through reducing gears, the gears having the same reduction, and because the parts of the head were supported next to each other, the rotation of the Hollow amber trees produces a simultaneous but opposite direction of the back and center of the head around the inclined axes. Thanks to this construction of hollow trees, there is now the possibility of carrying a transmission train from a drive shaft located internally through the hollow trees to a drive tree supported on the last part of the head and which is connected to the tool holders.

Through the DE-OS 34 31 033 it is already known also in a transmission head that has three head parts, supporting and coaxially operating with respect to the drive shaft (in the extended position of the transmission head) a tree connected to the tool holder , to guide cables, hoses, pipes or the like through the interior space. In this arrangement, the rear part of the head is not operated directly but through a cogged inclined cogwheel crown, coupled with a cogged crown that is located in the front part of the head, the point gear meshed out of The central part of the head. When the central part of the head then rotates, the back of the head is obliged, as a result of its support in the central part of the head, to follow this movement. But due to the fact that there is precise toothed gear with the front part of the head, a rolling movement of the rear part of the head takes place in the crown of the front part of the head, which produces a wobble of the back of the head When, on the contrary, the front part of the head is turned, the rear part of the head performs at the same time an unwanted own turning movement with an approximately equal turning angle. The own turning movement is the consequence of relative turning movements of the transmission parts supported within each other and therefore influencing each other. In addition, there is a notable negative effect of the toothed error and the set of teeth on the spatial arrangement of

000 697 the head parts because strongly reducing gears are not provided in the known transmission head on the force output side which could produce a reduction in errors and the effect of relative turning movements.

On the contrary, a considerable improvement is achieved by the fact that internal toothed lubricated in oil bath and supports are used through strongly reducing gears on the force output side, which leads to a very compact construction with greater and more constant over time accuracy of movements. Relative turning movements can only be compensated effectively and through the control in relation to reduction.

With the invention, it was also recognized that the elimination of the numerical ambiguity published with the teaching of DE-OS 34 28 748 is not the only possible ionic and especially when the toolholder or the flange plate was rotatably supported and operated in the back of the head The characteristics indicated in the secondary claims 5 to 10 show additional possibilities of eliminating numerical ambiguities.

Details of the invention are shown schematically and by way of example. They show:

Figure 1

A symbolic side elevation of a transmission head in its extended position.

Figure 2

A side elevation followed Figure 1 with an inclined force outlet.

Figure 3 and 4

Side elevations of the transmission head in matching turning positions.

Figure 5 and 11

Elevations of different transmission heads with specially positioned inclined shafts and Figure 12 to 14

Longitudinal cuts of three constructive examples of realization.

Figure 1 corresponds to Figure 1 of DE-OS 34 28 748 and wishes to highlight that there is an ambiguity for the numerical control when on the back 3 of the head it was rotatably supported and operated a tool holder or a flange plate 38 around a force output shaft 46 coaxially positioned relative to the drive shaft 4. It would indeed be possible to rotate the tool holder around the force output shaft 46 also by rotating the front part 1 of the transmission head around the drive shaft 4. This ambiguity could be avoided in this case only when the front part 1 of the transmission head was located without rotation around axis 4.

With 5 and 6, inclined rotation axes are designated around which the relative rotation movement of the central part 2 of the transmission head relative to the rear or anterior part (3,1) of the transmission head takes place.

Fig. 2 shows a possibility of avoiding such ambiguity by placing the force output shaft 46 with an acute angle inclined towards the drive shaft 4. The force output shaft 46 should preferably cut the cutting point 9 of the two inclined shafts 5.6 to facilitate the calculus of movement processes. Conical wheels for actuating flange plate 38 are schematically represented with 33 and 34. When a turning movement of the tool holder 38 around the axis 46 is to be made, it is obvious that this does not correspond to the drive of the front part 1 of the transmission head. Therefore ambiguity is avoided.

Lasfig 3 and 4 correspond to fig. 2 and 4 of the DE-OS 34 28 748. It is recognized that in both cases, the rear part 3 of the head is rotated by the angle 2α with respect to the drive shaft 4, using different rotary drives. In the first case, the rear part of the head 3 is rotated 180 ° with respect to the central fixed part 2 of the head. In the second case, the central part 2 of the head, with the rear part 3 of the head remaining in the same position with respect to that, rotates 180^° with respect to the front part 1 of the head. The ambiguity produced by this can be eliminated with one of the variants according to fig. 5 to 11.

In the example of fig. 5, the angles α1 and α2 of the two inclined axes 5 and 6 have different values, so that their cut-off point 9 is displaced laterally with respect to the symmetry position of fig. 1. The same turns of parts 2 and 3 of the head therefore lead to different angular positions between each other.

In fig. 6 it is shown that the inclined axis 5 is inclined in such a way that the drawing plane 9 of the two inclined axes 5 and 6 remains in the plane of the drawing. With the ellipse 47 the inclined plane of rotation is symbolized along which the two parts 1,2 of the head are guided side by side.

Fig. 7 broadens this idea since the two inclined axes 5, 6 are inclined out of the drawing plane. The examples in fig. 5 to 7 show possibilities to avoid the ambiguities indicated in fig. 3 and 4. In the case of fig. 7, the cutting point 9 of the inclined axes 5, 6 may be separated from the axis 4 or also in the plane of the drawing.

A remarkable simplification of the calculation of automatic movement controls is achieved when the cut-off point 9 'of the inclined axes 5, 6 was on the axis 4 and when the force output shaft 46', 46 ", 46" 'cuts this 9 'cut point. To highlight the manifestation, it should be noted that in the examples indicated for this in fig. 8 at 11, the force output shaft 46 receives the designation 46 ', when it is located coaxial with respect to the drive shaft 4 and cuts the point 9' (fig. 8 and 10). It receives the designation 46 ”when it forms an oangle with the drive shaft 4 but also cuts from point 9 '(fig. 9 and 10).

The configuration according to Figure 8 is developed from the arrangement according to Figure 1 by the fact that the inclined trees 5.6 are supported on the front and rear 1.3 of the transmission head displaced laterally until their axes are cut on the axis of

000 697 action 4.

In the example of figure 9, the inclined position of the force output shaft 46 "with respect to the drive shaft is further shown, which, as already mentioned, eliminates the ambiguity of the control of these axes. The axis 46 "can also be brought to coincide with the axis 6 and be called axis 46" ', which is equivalent to a reduction of the transmission elements and with it the cost of construction on one side and another side to a reduction of the space of movement but that is enough for many application cases.

Due to the coaxiality of axes 6 and 46 "'there is no harmful numerical ambiguity because in the case of a simultaneous transmission coupling of axes 5 and 6, the latter has no function as an individual axis.

Figures 8 and 9 start from the basis that axes 4, 5, 6, 46, 46 ”, 46” 'in the extended position of the beon transmission head located in the plane of the drawing. In the case of figure 8 the ambiguity appreciated in figures 3 and 4 is not yet defined. But as we know from figures 6 and 7, this ambiguity can be eliminated by means of axes 5,6 that are inclined out of the plane of the drawing. This measurement, together with the coaxial position of the cut-off point 9 'of the axes 4, 5, 6, 46', 46 ", 46" ', leads to the embodiment examples of figures 10 and 11.

Figures 10 and 11 show a variant of Figure 7 in side elevation and plan view, showing the different parts 1, 2 and 3 of the head side cantilever housing parts for the support of the inclined axes 5, 6 protruding towards the rear and in front of the drawing plane and the cutting point 9 'of these inclined axes 5, 6 being located in the drawing plane and being the final common point of axes 4 and 46', 46 ”. In addition, the force output shaft 46 "is inclined, which has the consequence that it was not aligned with respect to the drive shaft 4 in the drawing plane and thus no numerical ambiguities occur.

The cut-off point 9 'of axes 4, 5, 6, 46', 46 ", 46" 'shown in Figures 8 to 11 can be followed by the invention the central point of a spherical or cardan joint 49, through which the drive shaft 4 was connected with the force output shaft 46 ', 46 ", 46"' movable in space. This spherical or cardan 49 joint was represented symbolically. It allows several constructive configurations.

FIGS. 12 to 14 show construction examples for actuation of the flange plate 38 starting from FIG. 1, the coaxial force output shaft 46 being located in FIG. 12 and in parallel FIG. 13 in relation to the axis of drive 4. Figure 14 is the constructive example of embodiment of Figures 8 and 9. The cut-off point 9 'of axes 5, 6 is the final common point of axes 4 and 46', 46 ", 46" '. The inclined positioning of the drive shaft 35 located on the force output shaft 46 ", 46" 'is advantageous mainly in so-called linear control manipulators to avoid numerical ambiguities. In the constructive embodiment, an internal drive amber 13 was connected through the conical wheels 14, 15 with hollow amber 16, which was pivotally connected with the central part 2 of the head through a reduction gear 17. This central part 2 of the head rotates around the axis of rotation 5 through this arrangement of conical wheels 14, 15. It was guided around a perpendicular plane with respect to the axis of rotation 5 through suitable supports 40 in the front part1 of the head.

The outer drive amber 26 operated through the reduction gear 27 directly on the front part 1 of the head, which is located coaxial with respect to the arm 28 and rotatably supports it. All the reduction gears 17, 25, 27, 36 are placed on the force output side, which results in a construction of the transmission head that is largely free of play, compact and thereby of small dimensions. These reduction gears 17, 25, 27, 36 are provided for high reductions.

Along the second inclined axis of rotation 6 there is a hollow tree 32 that was connected to the hollow tree 16 that precedes it through conical wheels 44, 45. The hollow amber 16 drives, traversed through the gear 17 of strong reduction which is rest on the front part 1 of the head, the central part 2 of the head around the inclined axis of rotation 5. The other hollow amber 32 is supported with the strong reduction gear 25 in the central part 2 of the head and drives the rear part 3 of the head around the second inclined axis of rotation 6. The reductions of both gears 17,25 have the same magnitude and are preferably mounted symmetrically with each other, which has as a consequence that the parts 2, 3 of the head supported between each other make when turning the hollow amber trees 16, 32 a simultaneous movement of turn though in the opposite direction.

In this way, it is possible to guide through the hollow trees 16, 32 a drive train that starts from the central drive tree 18 and traversed the inner intermediate trees 21, 24 and the pairs 22, 23 and 33, 34 of conical wheels on a drive shaft 35, which is supported by a strongly reducing gear 36 on the back 3 of the head. In this way, a flange plate 38 is operated which was guided through the support 37 on the back 3 of the head and which houses the tool holder.

The rear part 3 of the head was rotatably guided through the support 39 in the central part 2 of the head, or through the support 40 in the front part 1 of the head. The intermediate amber 24 is guided on the force outlet side at the rear 3 of the head traversed by the support 41 and on the drive side in the hollow shaft 32 in the central part 2 of the head through the support 42.

In the drawing of Figure 12, the cut-off point 9 of the inclined axes is provided separately from the drive shaft 4. But this cut-off point 9 can also be located on the drive shaft 4, as shown in the figure 13. Next, a displacement of the intermediate part 29 is introduced in the embodiment example with the aid of the flange parts 30 and 31.

The consequence of this is displacement

000 697 side of the drive shaft 35 parallel to the drive shaft 4. If this is desired, for example, for the point-to-point controls, a rear displacement 48 can be provided on the back of the head for the support of the drive shaft 35 , which eliminates lateral displacement and thereby ensures that the drive shaft 35 is coaxial with respect to the drive shaft 4 in case of extended position of the transmission head 1, 2, 3. Figure 14 shows a constructive example of performance for linear control manipulators to avoid numerical ambiguity in which the inclined position of the force output shaft 46 "is preferred. The force output shaft 46 ', figure 14 is obtained from the rear displacement 48 of the drive shaft 35 following Figure 13.

The inclined position of the force output shaft 46 "with respect to the drive shaft 4 may not only be oriented downwards as shown in Figure 14, but also upwards as indicated by stroke and dot. Even a special inclined position, for example within the drawing plane or outside it, can be performed and could be used to solve the problem posed.

000 697