DE10249334A1 - Positioning system for moving a bogie truck in overhead gantry robot systems has an electromagnetic linear drive mechanism with active and passive units for moving the bogie truck - Google Patents

Abstract

An active unit (AU) (10) links to a bogie truck (BT) and a passive unit (PU) (11) extends along an overhead gantry girder (OGG) (3) supporting the BT moving lengthwise to the OGG. The AU has two opposing outwardly turned bearing surfaces of the same kind for making a controlled electromagnetic flux available. The PU has two opposing magnetic flux areas of the same kind.

Description

The present innovation concerns a positioning system with an electromagnetic linear drive for moving a first carriage, the linear drive in known manner has an active unit and a passive unit, wherein the active unit is connected to the carriage and wherein the passive unit extends along a portal support on which the carriage along to the portal girder is arranged movably.

For the movement and positioning of parts in multi-dimensional machining rooms, so-called portal systems are used, especially for larger travel distances. From the DE 41 27 446 A1 a portal robot for multi-dimensional movement of parts is known. A portal girder, which is supported by stationary supports, spans a processing area. A driving unit is guided on this gantry carrier, which enables movement along the gantry carrier. By means of several drives, a gripping unit can also be moved transversely to the gantry carrier and can also carry out a change in height perpendicular to the two aforementioned movement axes. The gantry robot thus enables at least movements along three mutually perpendicular axes X, Y, Z. Rotary movements can also be implemented via further drive units. In this known portal robot, the drive along the linear axes is carried out by conventional motors and using gears and guide units. The details of the drives are in the DE 41 27 446 A1 not explained.

In the DE 44 43 467 C1 A linear drive is shown with a stationary guide rail and a primary slide that can be moved on it. The guide rail is attached to a portal bracket. The slide is caused to move along the guide rail via a gear motor and a toothed belt. A secondary slide with its own drive is arranged on this primary slide, and the secondary slide can be moved transversely to the primary slide. In addition, a movable vertical slide is provided, which enables movement along a third linear axis.

Such portal systems have in common that along the main axis of movement, i.e. parallel to the portal girder, relative size Travels can be realized usually more than 2 m and also beyond 10 m. On the used portal beams can If necessary, several carriages can be moved if this is the drive units allow. Mostly is over a second drive controllable a second axis of movement, the runs in a parallel plane transverse to the first axis of movement. In order to Any points within the machining area can be approached can, a third axis of movement is required that is perpendicular to the two other axes of motion and possibly only one relative must have a small travel.

The drive of the carriage towards the main axis of movement (parallel to the portal girder) can, for example, under Use a rack if there is a motor on the carriage drives a pinion, which is in engagement with the rack. The achievable speeds for rack and pinion drives are relatively low and there are annoying noises, increased wear and positioning inaccuracies due to existing game.

Another known drive variant for portal systems consists in the use of toothed belts or comparable rope drives. In both cases the dynamic that can be achieved when moving the carriage is limited. There is a particular problem when using toothed belt drives in the occurrence of vibrations, the quick and accurate positioning prevent.

Portal systems are also known the electromagnetic linear motors as direct drives for the carriages use. Such linear motors (linear synchronous motors) have an active unit with a tread and coil systems which is a changeable Magnetic flux is generated. A passive unit is also provided, which has magnetic flux areas with permanent magnets and yoke elements, to a relative force between active unit and passive unit produce. There is an air gap between the active and passive units, which enables a relative movement. ever Depending on the application, either the active unit or the passive unit emotional. The general structure of such linear synchronous motors is known. For a detailed explanation of how it works and the construction of electromagnetic linear motors can be on this Place therefore to be waived.

Usually magnetic forces act between the active unit and the passive unit have a strong appeal and from those deployed guide units must be included. If linear motors were previously used in portal systems, were therefore more complicated, more expensive and larger-sized management units (E.g.

Recirculating ball bearings) required high frictional forces result, which affects highly dynamic movements.

One task of the present innovation is thus in providing a portal system that uses an electromagnetic Synchronous linear motor used as the drive source to the associated Advantages over to realize other drives. At the same time, the disadvantages to be avoided, which resulted from previously necessary management units when using linear motors.

These and other tasks are accomplished by solved the positioning system according to the innovation, in which the active unit has two similar opposing, outwardly facing treads and the passive unit comprises two similar opposing magnetic flux areas with permanent magnets, between which a trough is formed which extends parallel to the portal support, the active unit in the The trough is guided and the sum of the magnetic forces acting between the active unit and the passive unit perpendicular to the running direction is essentially zero.

With this design, the linear drive is through two drive levels are formed, which are parallel to each other. The functionally between the tread of the active unit and the Magnetic flux range of the passive unit occurring magnetic attraction forces with the same design of the two drive levels the same size and effect in the opposite direction so that the cross to the direction displacing forces acting on the active unit cancel each other out. The leadership unit of the positioning system between the first carriage and the portal bearer is arranged, therefore does not have to absorb lateral displacement forces. This reduces friction losses in the guide unit, which makes the positioning system operate much more dynamically can be.

According to an advantageous embodiment the leadership unit from two guide rails attached to the underside of the portal girder, with which the first carriage is engaged. The guide rails take the weight of the Carriage and any other attached to it Units on. In a modified embodiment can also guide plates on the portal girder be attached, which interact with rollers, which on the carriage are attached. Unlike with positioning systems after State of the art is the inclusion of those acting transversely to the direction of travel forces not required or at least to a much lesser extent, because there are permanent lateral forces of attraction from the linear drive result, do not occur.

In a further developed embodiment a transverse positioning system with a second on the first carriage Carriage attached. This cross positioning system corresponds in its structure largely the positioning system already explained, whereby the function of the portal carrier through took over the first carriage becomes. The transverse positioning system enables the second to move Carriage in a second direction, so that two-dimensional positioning is possible. This embodiment can be further developed by using the second carriage a height positioning system is attached with a third carriage. The three motion axes available with it are preferably perpendicular to each other for three-dimensional positioning to enable using simple known control systems.

Embodiments are also possible which several first carriages are movably arranged on the gantry. Each carriage has its own active unit as a drive source, where all active units work together with the same passive unit. Over a suitable control Naturally Collisions between the individual carriages can be avoided.

Other advantages, details and Further developments of the present innovation result from the following Description of preferred embodiments, with reference to the drawing. Now show:

1 is a schematic perspective view of a positioning system with three axes of motion according to the prior art;

2 two views of a first embodiment of a positioning system with a linear drive according to the present innovation;

3 two views of a second embodiment of the positioning system according to the present innovation;

4 a schematic diagram of the linear motor of the positioning system.

1 shows a schematic perspective view of a positioning system, as is known in its basic components from the prior art. The possible machining space can be described by a coordinate system, as it is in the 1 is illustrated by the three coordinate arrows X, Y, Z. Such a positioning system comprises, for example, two base plates 1 , each with a support column 2 is put on. Between the opposite pillars 2 runs a portal girder 3 , A first carriage 4 is driven by a drive parallel to the gantry 3 moves, as shown by the movement arrow. In the example shown, the first carriage 4 So moved in the X direction. The positioning system also has a second carriage 5 and a third carriage 6 , which can be moved in the Y direction and Z direction, respectively.

2 shows two detailed views of a first embodiment of the positioning system according to the innovation, the right representation being a cross-sectional view of the portal carrier, while the left representation is a frontal view of the portal carrier. The respective viewing direction is made understandable by the coordinate arrows assigned to the representations. The movement information mentioned below also refers to these coordinates.

The portal bearer 3 consists, for example, of a square profile made of the most rigid material possible in order to reduce vibrations and temperature dependencies. At the bottom of the portal door gers 3 are two guide rails 8th attached with guide elements 9 of the first carriage 4 are engaged. The from the guide rails 8th and the management elements 9 The guide unit formed enables the first carriage to be moved 4 in the X direction, i.e. in the longitudinal direction of the portal girder 3 , The drive of the first carriage 4 is done by an electromagnetic linear motor (direct drive), which is an active unit 10 and a passive unit 11 includes. The passive unit 11 is at the bottom of the portal beam 3 attached and has two similar magnetic flux areas, so that a channel is formed between these magnetic flux areas, in which the active unit 10 intervenes. The active unit 10 has, in turn, two similar treads, which are arranged on the outside and face the magnetic flux areas of the passive unit during operation. The attraction forces caused by the magnetic fields (permanent magnetic fields and electromagnetic fields) between the active unit and the passive unit are balanced out by this symmetrical structure, so that the forces resulting in the Y direction and in the Z direction are essentially zero.

Because the active unit 10 fixed with the first carriage 4 is connected, it is moved in the X direction when the linear motor is driven by drive currents. The guide rails 8th and the guide elements 9 do not have to absorb any or only very small forces in the Y direction. Of course, this affects the management unit 8th . 9 the weight of the first carriage 4 and the other units attached to it in the Z direction.

It's supposed to be another special one Advantage to be drawn from the attachment of the linear drive on the underside of the portal beam results. This positioning means that the drive is better protected against contamination protected, thereby its operational capability improved in industrial environments. Especially in manufacturing areas certain contamination levels cannot be avoided. For example metal chips are stored or other impurities preferably on the permanent magnet the passive unit but also on the treads of the active unit, if this are aligned horizontally. Due to the vertical arrangement below the portal bearer the linear drive is well protected against such contamination.

To enable positioning in the Y direction, the first carriage is 4 a transverse positioning system arranged. This essentially consists of the same elements as the positioning system described above, which is responsible for the movement of the first carriage in the X direction. At the bottom of the first carriage 4 are second guide rails for this 15 arranged with second guide elements 16 are engaged. The second guide 16 are in turn on the second carriage 5 attached, which is movable in the Y direction. A second linear drive with a second active unit acts as the drive 18 and a second passive unit 19 , As for the drive of the second carriage 5 the same principle is used as for the drive of the first carriage, there are no undesired lateral forces, so that the expenditure for the guide unit is also low and high positioning accuracy can still be achieved.

It should be noted that by the chosen one Principle, manual set-up mode is also possible, because the linear motors can also be moved without power. at usual Portal systems, this is normally not possible because the frictional forces in the required leadership units are too big.

The arrangement of the entire drive elements below the portal girder also brings the The advantage is that the forces introduced by payloads are evenly distributed the leadership units act, which in turn simpler and cheaper guides can be used.

As in 2 can also be seen, is in the embodiment shown below the second carriage 5 the third carriage 6 that can be moved vertically, i.e. in the Z direction. A short-stroke cylinder, for example, serves as the drive for the vertical movement 20 , The management of the third carriage 6 in this case takes place via management pillars 21 ,

3 shows two detailed views of a second embodiment of the positioning system according to the innovation. Here, too, the right representation is a cross section through the gantry 3 , while the left illustration shows a detail of a frontal view of the gantry. At the bottom of the portal beam 3 is again the passive unit 11 of the linear actuator. The first carriage 4 carries the active unit 10 of the linear drive.

To simplify, in 3 only the first carriage 4 including its drive and guide elements, which in turn enables movement in the X direction (parallel to the gantry). The other elements that are required for movement in the Y direction and Z direction have been described in 3 not shown.

The main difference of the embodiment according to 3 compared to the embodiment described above consists in the design of the guide unit. In this case, are on the underside of the portal beam 3 two flat rails 23 attached with casters 24 interact, which in turn on the first carriage 4 are attached. Because the casters 24 on the opposite faces of the two flat rails 23 attack, lateral guidance of the first carriage in the Y direction is guaranteed. However, this guide must absorb much less lateral forces than with the positioning system the prior art, where the guide unit must also absorb the attractive forces between the active unit and the passive unit of the linear drive.

4 shows a sectional view of the basic structure of the linear drive, which is used for driving the first carriage in the X direction. It can be seen that the two-part passive unit 11 on both sides of the active unit 10 extends. The two surfaces of the passive unit 11 , which form the trough for the active unit, each have magnetic yoke areas 25 and a variety of permanent magnets 26 , As is generally known from synchronous motors, the permanent magnets are 26 aligned with alternating polarity. In order to be able to generate the relatively high driving forces required, the active unit 10 several iron cores 27 used on which electrical coils 28 are wound up. The iron cores 27 extend I-shaped between the two treads of the active unit 10 , the magnetic flux areas of the passive unit 11 are opposite each other. If the coils 28 are energized by a control unit in a known manner, the active unit moves 10 due to the magnetic forces acting in the X direction. The one between the iron cores 27 and the permanent magnet 26 Lateral forces are largely compensated by the symmetrical structure of the linear drive, so that the active unit 10 resulting force in the Y direction is substantially zero.

Further modifications of the positioning system according to the innovation are conceivable. The decisive advantages over conventional positioning systems result from the use of a specially configured linear drive, which no gear elements or other power transmission elements are required and also the magnetic attraction between active unit and passive unit by a symmetrical Construction balances so that the leadership units do not have to absorb any or only very low transverse forces.

The arrangement also brings of the linear drive on the underside of the portal beam opposite the Arrangement of the drive on the side wall of the portal girder considerable Advantages with regard to the design of the management units.

1

foot plates

2

support column

3

straddle carrier

4

first carriage

5

second carriage

6

third carriage

8th

guide rails

9

guide elements

10

active unit

11

passive unit

15

second guide rails

16

second guide elements

18

second active unit

19

second passive unit

20

Short stroke

21

guide columns

23

flat bars

24

castors

25

Inference areas

26

permanent magnets

27

iron cores

28

Do the washing up

Claims (10)

Positioning system comprising: - a portal support ( 3 ) extending in a first direction (X); - a first carriage ( 4 ), which is in the first direction (X) along to the portal girder ( 3 ) is mobile; - a management unit, via which the portal girder ( 3 ) and the first carriage ( 4 ) are coupled; - an electromagnetic linear drive for moving the first carriage ( 4 ) with an active unit ( 10 ) connected to the carriage and a passive unit ( 11 ), which extends in the first direction (X) over the entire travel path of the linear drive; characterized in that: - the active unit ( 10 ) has two similar, opposite, outwardly facing treads for providing a controlled electromagnetic flow; - the passive unit ( 11 ) two similar opposing magnetic flux areas ( 25 . 26 ), between which a trough extends in the first direction (X); - the active unit ( 10 ) is guided in the trough, the sum of the magnetic forces acting between the active unit and the passive unit perpendicular to the first direction (X) being essentially zero. Positioning system according to claim 1, characterized in that the portal support ( 3 ) runs over an essentially horizontal processing surface and the passive unit ( 11 ) is attached to the underside of the portal beam facing the processing surface. Positioning system according to claim 1 or 2, characterized in that between the treads of the active unit ( 10 ) and the magnetic flux areas ( 25 . 26 ) of the passive unit ( 11 ) an air gap remains. Positioning system according to one of claims 1 to 3, characterized in that the guide unit consists of two on the portal support ( 3 ) attached guide rails ( 8th ) and on the first carriage ( 4 ) attached guide elements ( 9 ) consists. Positioning system according to claim 4, characterized in that the guide elements ( 9 ) are designed as ball bearings, roller bearings, recirculating ball bearings or similar low-friction motion bearings. Positioning system according to one of claims 1 to 3, characterized in that the guide unit consists of two on the portal support ( 3 ) fixed flat rails ( 23 ) and several on the first carriage ( 4 ) attached rollers ( 24 ) is formed. Positioning system according to one of claims 1 to 6, characterized in that on the first carriage ( 4 ) a cross positioning system with a second carriage ( 5 ) which is essentially constructed like the positioning system defined in the preceding claims, the function of the gantry carrier in the transverse positioning system being the first carriage ( 4 ) is fulfilled and the second carriage ( 5 ) in one of the first direction (X). Different second direction (Y) is movable, thereby enabling two-dimensional positioning. Positioning system according to claim 7, characterized in that on the second carriage ( 5 ) a height positioning system with a third carriage ( 6 ) is attached, the third carriage ( 6 ) is movable in a third direction (Z) perpendicular to the first and second directions, in order to enable three-dimensional positioning. Positioning system according to one of claims 1 to 8, characterized in that on the portal support ( 3 ) several first carriages ( 4 ) are arranged, which are assigned via respectively assigned active units ( 10 ) can be moved individually in the first direction (X). Positioning system according to one of claims 1 to 9, characterized in that the linear drive is a linear synchronous motor, the active unit ( 10 ) several electrical coils ( 28 ) on iron cores ( 27 ), and the magnetic flux areas ( 11 ) through a variety of permanent magnets ( 26 ) and inference elements ( 25 ) are formed.