Planar-drive system, stator module and sensor module

Patent metadata

Field	Value
Publication number	US-11437893-B2
Application number	US-202016897985-A
Country	US
Kind code	B2
Filing date	Jun 10, 2020
Priority date	Dec 27, 2017
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A planar-drive system includes a rotor and stator module with a housing, a stator assembly for driving the rotor, and a sensor module for detecting the rotor position. The sensor module has a 2D arrangement of magnetic-field sensors arranged on a carrier in first and second periodic grids, extending in first and second directions. Adjacent magnetic-field sensors are arranged at first and second distances in the first and second directions. The grids are shifted by a vector having first and second components smaller than the respective first and a second distances. The rotor has first and second magnet units, each with an arrangement of magnets with first and second periodic lengths aligned in the first and second directions. The first and second components of the vector, and a difference between the first and second distances and the respective components, are each smaller than the respective first and second periodic lengths.

First claim

The invention claimed is:

1. A planar-drive system, comprising:
a rotor, and
a stator module, wherein the stator module comprises a stator-module housing, a stator assembly for electrically driving the rotor and a sensor module for detecting a position of the rotor;
wherein the rotor is configured to be driven over a planar stator surface of the stator assembly at least in a first direction and in a second direction,
wherein the sensor module comprises a carrier and a two-dimensional arrangement of magnetic-field sensors,
wherein the magnetic-field sensors are arranged on the carrier,
wherein the two-dimensional arrangement of magnetic-field sensors comprises a first sub-arrangement of first magnetic-field sensors,
wherein the first magnetic-field sensors of the first sub-arrangement are arranged in a first periodic grid,
wherein the first magnetic-field sensors are arranged in the first periodic grid along the first direction and along the second direction,
wherein adjacent first magnetic-field sensors of the first sub-arrangement are arranged at a first distance with regard to one another in the first direction,
wherein adjacent first magnetic-field sensors of the first sub-arrangement are arranged at a second distance with regard to one another in the second direction,
wherein the two-dimensional arrangement of magnetic-field sensors comprises a second sub-arrangement of second magnetic-field sensors,
wherein the second magnetic-field sensors of the second sub-arrangement are arranged in a second periodic grid,
wherein the second magnetic-field sensors are arranged in the second periodic grid along the first direction and along the second direction,
wherein adjacent second magnetic-field sensors of the second sub-arrangement are arranged at a first distance with regard to one another in the first direction,
wherein adjacent second magnetic-field sensors of the second sub-arrangement are arranged at a second distance with regard to one another in the second direction,
wherein the first sub-arrangement and the second sub-arrangement are arranged shifted relative to one another by a vector,
wherein the vector has a first component in the first direction and a second component in the second direction,
wherein the first component is smaller than the first distance, wherein the second component is smaller than the second distance,
wherein the rotor comprises a first magnet unit, wherein the first magnet unit comprises a first periodic arrangement of magnets having a first periodic length,
wherein the first periodic arrangement of magnets is periodic in the first direction,
wherein the first magnet unit is oriented in the first direction during operation of the planar-drive system,
wherein the rotor comprises a second magnet unit, wherein the second magnet unit comprises a second periodic arrangement of magnets having a second periodic length,
wherein the second periodic arrangement of magnets is periodic in the second direction,
wherein the second magnet unit is oriented in the second direction during operation of the planar-drive system,
wherein the first component is smaller than the first periodic length,
wherein a difference between the first distance and the first component is smaller than the first periodic length,
wherein the second component is smaller than the second periodic length, and
wherein a difference between the second distance and the second component is smaller than the second periodic length.

2. The planar-drive system according to claim 1 ,
wherein the stator assembly is arranged on an upper side of the stator-module housing,
wherein the carrier is arranged below the stator assembly in the stator-module housing,
wherein the carrier has a through-opening,
wherein the stator-module housing comprises a heat-conducting structure,
wherein the heat-conducting structure is embodied to dissipate heat from the stator assembly to a bottom side of the stator-module housing opposite to the stator surface,
wherein the heat-conducting structure is guided from the stator assembly to the bottom side of the stator-module housing via the through-opening,
wherein the through-opening adjoins four magnetic-field sensors,
wherein two first magnetic-field sensors thereof are assigned to the first sub-arrangement and two second magnetic-field sensors thereof are assigned to the second sub-arrangement.

3. The planar-drive system according to claim 1 , wherein the first periodic length is a product of a first rational number and the first distance, wherein the second periodic length is a product of a second rational number and the second distance, and wherein the first rational number and the second rational number are between 0.5 and 1.

4. The planar-drive system according to claim 3 , wherein the first rational number is five sixths and wherein the second rational number is five sixths.

5. The planar-drive system according to claim 1 , wherein the first component corresponds to half of the first distance and wherein the second component corresponds to half of the second distance.

6. The planar-drive system according to claim 1 , wherein the first distance and the second distance are equal.

7. The planar-drive system according to claim 1 wherein the first direction and the second direction are perpendicular with regard to each other.

8. The planar-drive system according to claim 1 ,
wherein the stator surface is a parallelogram,
wherein a length of a first parallelogram side of the stator surface is a first integral multiple of the first distance,
wherein a length of a second parallelogram side of the stator surface is a second integer multiple of the second distance,
wherein the first parallelogram side is oriented in parallel to the first direction, and
wherein the second parallelogram side is oriented in parallel to the second direction.

9. The planar-drive system according to claim 8 , wherein the stator surface is rectangular, in particular square.

10. The planar-drive system according to claim 8 , wherein the first integer multiple and the second integer multiple are identical.

11. The planar-drive system according to claim 8 ,
wherein the carrier is arranged in such a way that a first corner magnetic-field sensor of the first sub-arrangement is arranged below a first corner region of the stator surface,
wherein the first corner region of the stator surface is arranged at a point of intersection of a first parallelogram side and a second parallelogram side,
wherein the first corner magnetic-field sensor is in the first direction positioned at a quarter of the first distance from the second parallelogram side of the stator surface,
wherein the first corner magnetic-field sensor is placed in the second direction positioned at a quarter of the second distance from the first parallelogram side of the stator surface,
wherein a second corner magnetic-field sensor of the second sub-arrangement is arranged in a second corner region of the stator surface opposite to the first corner region,
wherein the second corner region of the stator surface is arranged at an intersection of a third parallelogram side and a fourth parallelogram side,
wherein the second corner magnetic-field sensor is in the first direction positioned at a quarter of the first distance from the fourth parallelogram side of the stator surface,
wherein the fourth parallelogram side is opposite to the second parallelogram side, wherein the second corner magnetic-field sensor is in the second direction positioned at a quarter of the second distance from the third parallelogram side of the stator surface, and
wherein the third parallelogram side is opposite to the first par

Assignees

• Beckhoff Automation Gmbh

Inventors

• Brinkmann Rolf
• Bentfeld Lukas
• Pruessmeier Uwe

Classifications

• G01R33/072

  Constructional adaptation of the sensor to specific applications · CPC title

• H02K11/215 Primary

  Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements · CPC title

• H02K2201/18

  Machines moving with multiple degrees of freedom · CPC title

• H02K1/20

  with channels or ducts for flow of cooling medium · CPC title

• G01D5/145

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title