DD146525B1 - TWO COORDINATE STEP MOTOR - Google Patents

Description

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Two-coordinate stepping motor Field of application of the invention,

The invention relates to a two-coordinate stepping motor, in particular for the rapid and accurate positioning of spatial and planar objects in the device technology for the location structure recognition or change. Such drives are particularly suitable for connection to digital signals generating electronic systems,

Characteristic of the known technical solutions

It is known that two-coordinate Bowegungsoinrichtungon exist in which cross tables are driven by rotationally operating stepper motor via a Hutter spindle pairing by means of longitudinally movable cardan shafts, via cables especially in xy-Schroibern odor directly via a spring-coupled play-free and querverschiebborc articulation. Also used as a drive are continuously operating rotary motors with clutches and brake devices in conjunction with incremental encoders and control devices. Also linear motors are vorwendet for driving cross tables. However, cross tables have a large mass for the dancer in the second coordinate when high positioning accuracy is necessary, and therefore they have an unfavorable dynamic; Hold.

In addition, according to the dom-reluctance principle, there are two-coordinate orthogonal stepping motors and polarized two-coordinate stepnotors. D. in United States Patent Hr. 40374! with through

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the manufacturability of tooth structures and Polo limited resolution.

In DD-PS 129 940 an arrangement is described box is located between a first and a second part, between which a magnetic flux closes, a third part, which is arranged so that between it and at least one of the first two Parts a relative movement is possible. For a step movement in a plurality of coordinate directions tracks and teeth for the movement along the individual coordinates are arranged so that there is always a sufficient Leitlenge each intersecting nested interconnect in the associated magnetic field.

The principles illustrated in Figures 3a to 3d show the arrangement of teeth and conductors to each other and machon three major drawbacks, which in a very small power generated at small step sizes due to the low allowable current load on thin conductors, the only possible relatively large increment as a result technologically limited manufacturability of smallest tooth widths and the case of fine pitches and traces due to low intensity undercirculation caused low step accuracy, especially when acting counter forces.

In US Pat. No. 3745433 a linear and a rotational movement of a shaft supported V / Alze is realized by special coil and magnet assemblies.

aim the invention

Ziol of the invention is to provide a two-coordinate stepping motor, with the quasidrehnotnentcnfreio forces on a table top for smallest Gchrittwoiten below l to realize and at dom Arrotiorung the table by switching off the fluidcn Führungsncdiums is guaranteed.

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Explanation of the nature of the invention

The invention has for its object to provide a two-coordinate stepper motor, which has a favorable dynamic behavior and also allows the smallest increments to less than l.um and the locking of the rotor in each position.

To avoid noncentric forces acting on the table, a coil assembly of at least one rectangular coil for each coordinate x, у mounted on a ferromagnetic base plate adapted form. A return cover is connected to the base plate so that an air gap remains over the coils. In this air gap, a non-magnetic movable table top is arranged, are arranged in the at least one, preferably a plurality of permanent magnet pairs with magnets of opposite polarity over the fixed coils for each coordinate direction x, у. The return plate has compressed air supply for a fluid guidance of the table top over the table top. In a preferably cross-shaped tabletop shape, the minimum width b ^ .,. the cross bar of the table through the compressed air supply surface width b _DF determined after the attraction b _s _ ... ^ 2 b _DF , so that the table does not come out of 'the effective area of the air cushion of the fluid guide. The magnetic pole _length l _vp is determined by the provided travel _path 3 and the coil _{strand width} b by the relationship

¹ MP ^{a S} v ^{+ b} s

established. The Spulenlängo is greater than the sum of Magnetpolbreite b _f , _o , the travel of the force acting direction of the relevant coil coordinate S., The double coil strand width 2 b and to avoid forces perpendicular to the drive direction through the coil head cross-strands and outgoing from the magnets leakage flux twice the amount of hail 2 hours after the relationship

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¹ S min> ^b MP ^{+ S} v ^{+ 2 b} s ^{+ 2 h} M

established. The magnet-facing side of the return cover has a plastic coating, preferably PTFE, to reduce the attractive forces and wear when switching off the compressed air. The shutdown of the compressed air also allows the magnetic clamping of the table top as a lock against external forces acting on the table top forces during standstill phases. The return cover has in addition to its four Cefestigungsstegen on the sides of two Flußführungsstrecken for lying near the bottom of the table magnets, so that by the opposite polarity of the magnets in the same flow paths no oppositely directed magnetic fluxes occur. The raster plates for the optoelectronic signal acquisition are arranged symmetrically to these additional Flußführungsstrecken. In the iiitte of Rückflußdeckels, the table and the base plate are radiation-permeable openings, wherein in the Tischnitta the slide plate, z. B. glass, is arranged.

With the help of Rasterplatton, which are illuminated by light sources and scanned by optoelectronic receivers Incre-aentale location signals for a connected position controller are generated upon movement of comparing the location signals with the supplied control signals and in accordance with the movements necessary to achieve the desired position, the respective coils of existing DC voltage sources corresponding polarity equivalent of the occurring control deviation with different long pulse time connects. The position information can also be obtained via a per se known Laserwegmeßsystem or other incremental encoder, then only the Laserinterferometerspiegel or other incremental encoder plates are arranged on the table top and the measured value processing takes place outside the table and no mass load results.

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Out of the box example

The invention is explained in more detail below with reference to an embodiment. The enclosed drawing shows:

Fig. 1 Zneikoordinatenschrittmotor in section AA with four permanent magnets in each coordinate direction x, у in a fluid-guided table top over fixed coils

Fig. 2 section B3 to Fig. 1st

Fig. 1 and Fig. 2 show a Zvvoikoordinatenschrittmotor in which for generating drehmomentenfreion Antriebkräftan at the cross-shaped table top 3 a Spulenonordnung of zv / ei Rechte.ckspulen 5 for each coordinate direction x, у mounted on a ferromagnetic base plate 1 adapted octagonal shape is. With the base plate 1, a return cover 7 is connected, which leaves an air gap over the coils 5, in which a cross-shaped table top 3 is arranged, which has in each cross bar on the rectangular coils 5 an oppositely polarized pair of permanent tenor 6 and in the center of the table itself the slide plate 9 is located. The Rückochlußdeckel 7 has in addition to its four Defestigungsstegen to the base plate 1 nor two special Flußführungsstrecken ID for dio near the middle of the table permanent magnets 6, the underside of the yoke is with a plastic layer 4, z. D. PTFc, coated, and at the top of compressed air supply lines 3 are provided which direct the compressed air to the distribution channels 15 in the return cover 7. In zwoi corners dor table top 3, the grid plates 11, 12 are fixed, which are illuminated by the light sources 13 and n'onotootot with the photo-scavengers 14 between the coils 5 on the ferromagnotic base plate 1 are non-magnetizable.

Claims (1)

216266 _G Erfindunnsonspruch 1. Zweikoordinatonschrittnotor, in which permanent magnets are arranged in a movable part which is guided in a plane fluid, which in turn is arranged on feston coils and are attached to the grid plates, interferometer or other incremental encoder plates for incremental signal acquisition and position control, characterized nokenn diagram in that, in a cross-shaped table top (3), the minimum bridge breadth b ~ i 2 Ό ηΓ is _arranged at least two permanently polarized permanent magnets (6) in each weighing coordinate (x, y) and rectangular coils (5) with the minimum length (1). firmly with a ferro- о Ϊ71 Χι) magnetic base plate (1) are connected and in that over the entire ilagnetpolflache, parts of the table top surface and the provided route (S) projecting, two special Flußleitstöcke (10) and in the (litte a recess owning Rückückdcckel (7) is present at the underside of a plastic layer (4), such as PTFE, and at the top of the feeds for the compressed air (3) and in the return cover (7) to the feeds of compressed air (8) distribution channels (16) are provided for the compressed air. For this 1 page drawings