DE102007037886B4 - Field-guided planar precision drive with an air-bearing rotor - Google Patents

Abstract

Field-guided planar precision drive with an air-bearing rotor (1), which is designed as a planar table, which has permanent magnet circuits (4), furthermore with a stator plate (6) located below the rotor (1), on the stator plate (6) each opposing drive coil pairs ( 3), in order to exert force effects on the rotor (1) with the permanent magnet circuits (4) depending on the energization of the drive coil pairs (3), the drive coil pairs (3) being arranged symmetrically in a right-angled xy coordinate system, furthermore the stator plate (6) linear guides (5), which are each at right angles to one another, for each drive coil pair (3) in order to achieve a movement of the drive coil pairs (3) along the respective x- or y-axis of the coordinate system, with an adjustment of the rotor ( 1) a force component in the x-direction for pulling or moving those opposite pairs of drive coils (3) vo r lies or is generated, which are used to adjust the rotor (1) in the y-direction, as well as an adjustment of the rotor (1) in the y-direction a force component for dragging or moving those opposite drive coil pairs (3) is present or generated which serve to adjust the rotor (1) in the x-direction, characterized in that the permanent magnetic circuits (4) are arranged along the outer edges of the underside of the planar table (1), the longitudinal extent of the drive coil pairs (3) is only slightly larger than the width of the permanent magnetic circuits (4) and the linear guides (5) are arranged symmetrically in a cross shape on the stator (6), each linear guide (5) receiving a pair of drive coils (3).

Description

The invention relates to a field-guided planar precision drive with an air-bearing rotor according to the preamble of patent claim 1.

From the DE 30 37 648 C2 is a two-coordinate motor for moving a slide with known for each movement coordinate of at least one coil and a relatively movable permanent magnet with iron yoke. In each movement coordinate x and y at least two oppositely polarized permanent magnets on a ferromagnetic base plate and in each case over the oppositely polarized permanent magnet, a ferromagnetic Rückschlussteil arranged. In the air gap between the permanent magnet and the return part is at least one associated with a table top coil with two opposite polarized permanent magnet associated, effective coil sides and with far beyond the Magnetpolbreite projecting coil ends. Furthermore, recesses are provided for the return part and in the center of the table of slides from radiation-permeable material in the aforementioned table top.

With this precision drive, it should be possible to improve the dynamic behavior, with even the smallest increments can be realized. Control deviations are determined optoelectronically, on the table only z. As laser interferometer or other incremental encoder plates are arranged so that there is no additional mass load.

To increase the force generated, to compensate or to generate torques or to prevent or generate rotational movements of small size at least four coils with the force effective coil strands to the center of the table in two parallel force lines of action for each coordinate x, y in the table top and the corresponding Permanent magnet pairs arranged on a ferromagnetic base plate or corresponding ferromagnetic portions of the base plate. The current in the coils is then adjusted by an existing position controller so that depending on the existing motion task a centrally acting sum force or even a torque on the table top is exercisable.

An evolution of the in the DE 30 37 648 C2 described embodiment is in the DE 195 11 973 A1 explained. Accordingly, should be dispensed with mechanical guide elements and a particularly flat design for a field-guided planar precision drive can be achieved. This object is achieved in that the planar drive according to DE 195 11 937 A1 consists of drive base elements comprising two oppositely polarized magnets, which form a short magnetic circuit via ferromagnetic yokes and a ferromagnetic stator, whereby relatively thin and therefore low-mass ferromagnetic yokes are used, which are moved in the rotor.

The realization of a large travel range should be achieved by means of a cascading of drive basic elements and preferably an electronic commutation. An opposite-phase energization of respectively opposite coils or pairs of coils allows the generation of a drive torque with respect to the center of mass of the rotor provided there. The rotor is supported by means of aerostatic guide elements at four receiving points on a total of four bearing surfaces in the z direction and carries the aforementioned permanent magnet circuits, which are arranged in pairs symmetrically opposite each coordinate x and y. To achieve a correspondingly large displacement, the expansion of the drive coil pairs in the longitudinal direction is substantially greater than the width of the local permanent magnet circuits, with the result that the cost of producing the coils is greater and the total weight of the assembly is increased.

The DE 601 09 635 T2 , which is based on the preamble of claim 1, relates to an XYZ positioning device, which shows a field-guided planar precision drive with a rotor. The rotor there has permanent magnet circuits and a stator plate below the rotor. In addition, drive coil pairs are provided on the stator plate in order to exert force effects on the rotor depending on the current supply of the drive coil pairs. Furthermore, it is disclosed in the document to arrange the pairs of drive coils symmetrically in a rectangular xy-coordinate system.

From the foregoing, it is therefore an object of the invention to provide an advanced field-guided planar precision drive with an air bearing rotor, which has a large travel range, without the power loss of the drive and the associated problems such. B. increase the warming.

The object of the invention is achieved by a field-guided planar precision drive with air-bearing rotor, which has permanent magnet circuits, according to the combination of features according to claim 1, wherein the dependent claims include expedient refinements and developments.

Starting from an air-bearing rotor, which has permanent magnet circuits and wherein below the rotor, a stator plate is present, which each has oppositely provided drive coil pairs to exert depending on the energization of the drive coil pairs force effects on the rotor with permanent magnet circuits there, the drive coil pairs are arranged symmetrically in a rectangular xy coordinate system, the stator has linear guides for each pair of drive coil to a To achieve movement of the drive coil pairs along the respective x- or y-axis of the coordinate system.

In an adjustment of the rotor in the x-direction is a force component for entrainment or Mitbewegen the opposite pairs of drive coil is or is generated, which serves to adjust the rotor in the y-direction. In an adjustment of the rotor in the y-direction is a force component for entrainment or Mitbewegen of those opposite pairs of drive coil or is generated, which serve to adjust the rotor in the x-direction.

The drive coil pairs are in the other, d. H. uncontrolled direction x or y, guided in a precision-guided manner over the entire range of motion of the active axis, d. H. also beweget. If then an energization of the corresponding pairs of drive coils, which are located on the coaxing axis, is an optimal position of the permanent magnet circuits before, with the result that the force generated in an optimal manner on the rotor for the purpose of adjustment can be brought to act. Thus, the disadvantage of the prior art can be eliminated, which is present at fixed stator coils. As the coil length increases, which is necessary to increase the travel distance, the power loss is known to increase in such a way that, in addition to the thermal problems on the planar motor, energy and production costs increase such that economical operation no longer seems possible.

In the variant of a planar precision drive with the mitbewegten drive coil pairs so much shorter coils can be used, which are cheaper to produce and also allow savings in the overall weight of the arrangement.

The force component for pulling or co-moving can be effected according to the invention by a pin or bolt fixed to the respective drive coil pair, which pin is guided in a groove, a rail or a slot in the rotor.

In an alternative embodiment, the force component for co-moving the respective drive coil pairs can be generated by a separate drive, which receives corresponding control information from a higher-level control of the precision drive.

This separate drive can be integrated into the respective linear guide and z. B. have a piezoelectric actuator.

The permanent magnet circuits of the field-guided planar precision drive according to the invention consist of a plurality of individual magnets arranged in a row, wherein preferably two spaced-apart magnets have a yoke for forming an iron yoke.

The permanent magnet circuits are symmetrical, extending in the x and y directions, arranged on the rotor and connected thereto.

In addition, the rotor is designed as a Planartisch, on the underside of the permanent magnet circuits are located.

The permanent magnet circuits according to the invention along the outer edges of the underside of the Planartisches, z. B. has a square or rectangular shape arranged.

The linear guides disposed on the stator may carry a carriage for receiving a respective pair of drive coils.

The longitudinal extent of the drive coil pairs according to the invention is only slightly larger than the width of the permanent magnet circuits with the aforementioned consequence of reduced costs in the production of shorter coils and a weight saving.

The linear guides are each made at right angles to each other standing, wherein preferably the linear guides are arranged in a cross shape symmetrical.

The guides, which each receive a pair of drive coils, as a closed sliding prism guide, as an open prismatic ball roller guide, as a closed sliding cylinder guide, but also as an air guide, d. H. areostatic leadership, be trained. The straightness of the movement is determined primarily by the geometric design of the paired surfaces, so that a correspondingly careful processing of these surface parts is required. To avoid parasitic effects, the respective guides are designed to be as low-friction as possible. Advantageous here are prismatic air ducts, which have an extremely low friction during movement and standstill and where there is no stick-slip effect.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Hereby show:

1 a perspective view of a field-guided precision planar drive with luftgelagertem rotor, on the underside of permanent magnet circuits are located, and

2 to 4 Representations of different displacement positions of the precision drive, wherein for reasons of clarity, the rotor is not shown in the form of a Planartisches.

The embodiment of a field-guided planar precision drive according to the illustration 1 goes by a runner 1 designed as a substantially rectangular or square planarian 1 is feasible. air bearing 2 enable a movement of the planarian 1 at least in the x and y directions according to the in the 2 to 4 indicated coordinate system.

The aerostatic Planartisch 1 as a rotor has symmetrically arranged on its underside permanent magnet circuits 4 each permanent magnet circuit consists of two high-performance permanent magnets on an iron yoke. The principle of moving magnets ensures a high stiffness of the air bearings, which on the high flatness manufactured stator 6 slide.

The stator 6 has an array of guides 5 on, which are realized as linear or linear guidance.

For recording the position of the planning table 1 this can include an unillustrated cross grid on an adjustable frame, which is scanned by a likewise not shown, centrally mounted on the stator measuring system to the positions of the Planartisches 1 in x- and y-direction or to detect a rotation.

In contrast to known embodiments of planar motors is now proposed, known per se, flat, rectangular drive coil pairs for the x and y axes not fixed on the stator 6 to attach, but these drive coil pairs 3 with the help of the guides 5 movable in the respective axial direction, ie to make it displaceable.

Will this be the consequence of 2 and 3 considered, there is a displacement movement of the Planartisches with the permanent magnet circuits in, x-direction instead. The drive coil pairs required for a displacement movement in the y direction 3 are pulled along by the corresponding permanent magnet circuits. For this purpose, a pin or bolt may be provided on the respective drive coil pair or a provided coil trolley, which comes into operative connection with a groove or a guide rail on the underside of the Planartisches, ie the rotor.

Alternatively, it is also possible to generate the force component for entrainment or co-movement of the respective pairs of drive coils by a separate drive which receives control information or control signals from a higher-level control of the precision drive. This separate drive can be integrated into the respective linear guide.

4 shows a completed movement of the planarian 1 with the permanent magnet circuits 4 in -y direction. During this movement, the drive coil pairs are pulled along 3 that is for a movement of the planarian 1 , ie the runner responsible in the x-direction.

In all shift positions of the plan table 1 each results in an optimal position between the permanent magnet circuits 4 and the associated drive coil pairs 3 at the same time securing a large adjustment or travel path, which in itself is only dependent on the spatial extent of the guides 5 on the stator 6 , Like also from the 2 to 4 It can be seen, the permanent magnet circuits consist of a plurality of arranged in a row of individual magnets, wherein preferably each two individual magnets have a yoke to form an iron yoke. The permanent magnet circuits are symmetrical, extending in the x- and y-directions, on the planar table 1 arranged.

Here are the permanent magnet circuits 4 preferably along the outer edges of the underside of the planographic table 1 , The linear guides 5 are at a right angle to each other and are preferably arranged symmetrically in a cross shape. From the figurative representation is further clear that the planar motor variant with moving drive coil pairs allows the use of shorter coils, which are cheaper to produce.

Without departing from the basic idea of the invention, the co-movement of the drive coil pairs can be achieved by either the respective drive coil pairs are mounted on the linear guide with its own drive, said respective linear drive is supplied by the central control of the planar mode with drive information, or it can As stated, the coil arrangements are collinear about the planarity 1 mechanically coupled, in which case for a movement resistance-free linear guide, z. B. in the form of an aerostatic guide, care.

LIST OF REFERENCE NUMBERS

1

Planartisch

2

air bearing

3

Drive coil pair

4

magnetic circuit

5

Guide, in particular linear guide

6

stator

Claims (8)

Field-guided planar precision drive with an air-bearing rotor ( 1 ), which is designed as Planartisch, which permanent magnet circuits ( 4 ), with one below the runner ( 1 ) located stator plate ( 6 ), on the stator plate ( 6 ) each provided opposite drive coil pairs ( 3 ), depending on the energization of the drive coil pairs ( 3 ) Power effects on the runner ( 1 ) with the permanent magnet circuits ( 4 ), the drive coil pairs ( 3 ) are arranged symmetrically in a rectangular xy-coordinate system, furthermore the stator plate ( 6 ) Linear guides ( 5 ), which are each at a right angle to each other, for each drive coil pair ( 3 ) to prevent movement of the drive coil pairs ( 3 ) along the respective x- or y-axis of the coordinate system, wherein in an adjustment of the rotor ( 1 ) in the x-direction, a force component for pulling or moving those opposite drive coil pairs ( 3 ) is present or generated, which of the adjustment of the runner ( 1 ) in y-direction, and in an adjustment of the runner ( 1 ) in y-direction a force component for pulling or moving those opposite pairs of drive coil ( 3 ) is present or generated, which of the adjustment of the runner ( 1 ) in the x-direction, characterized in that along the outer edges of the underside of the plan ( 1 ) the permanent magnet circuits ( 4 ), the longitudinal extent of the drive coil pairs ( 3 ) only slightly larger than the width of the permanent magnet circuits ( 4 ) and the linear guides ( 5 ) cross-symmetrical on the stator ( 6 ) are arranged, each linear guide ( 5 ) each a drive coil pair ( 3 ). Precision drive according to claim 1, characterized in that the force component for entrainment or Mitbewegen by one on the respective drive coil pair ( 3 ) fixed pin or bolt, which in a groove, rail or a slot of the rotor ( 1 ) is provided. Precision drive according to claim 1, characterized in that the force component for moving the respective drive coil pairs ( 3 ) is generated by a separate drive, which receives control information from a higher-level control of the precision drive. Precision drive according to claim 3, characterized in that the separate drive in the respective linear guide ( 5 ) is integrated. Precision drive according to one of the preceding claims, characterized in that the permanent magnet circuits ( 4 ) consist of a plurality of arranged in a row individual magnets with iron yoke. Precision drive according to claim 5, characterized in that in each case two permanent magnets are connected via a yoke in the iron yoke. Precision drive according to claim 5 or 6, characterized in that the permanent magnet circuits ( 4 ) symmetrical, extending in the x and y directions, on the runner ( 1 ) are arranged. Precision drive according to one of the preceding claims, characterized in that the linear guides ( 5 ) each a carriage for receiving a drive coil pair ( 3 ) wear.

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