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US 2010/0072830 A1Published application
Apparatus for determination of the axial position of the armature of a linear motor
AssigneeNti AG
InventorDaniel Ausderau
Life of this patent
Estimating the term…
Abstract
An apparatus (2;3;4;5) for determination of the axial position of the armature (11) of a linear motor comprises at least one pair of magnetically permeable, annular elements (12;20,21;30,31,34,35;40,41,44,45;48;50,51), which are arranged essentially coaxially and at a short distance (dr;db) from one another, such that an air gap (22;32,36;42,46) is formed between them, in which a magnetic field sensor (23;33,37;43,47;Si) for measurement of the magnetic field (B) in the air gap is arranged.
Claims12
1:
- Apparatus (2;3;4;5) for determination of the axial position of the armature (11) of a linear motor, having at least one pair of magnetically permeable, annular elements (12;20,21;
- 30,31,34,35;40,41,44,45;48;50,51), which are arranged essentially coaxially and at a short distance (dr;db) from one another, such that an air gap (22;32,36;42,46) is formed between them, in which a magnetic field sensor (23;33,37;43,47;Si) for measurement of the magnetic field (B,Br) in the air gap is arranged, with the two annular elements (12;20,21;
- 30,31,34,35;40,41,44,45;48;50,51) surrounding the armature (11) of the linear motor, in the installed state.
2:
- Apparatus according to claim 1, having at least two pairs (20,21,40,41;30,34,12;40,45,48) of magnetically permeable, annular elements, with, in the case of pairs which are arranged adjacent, two annular elements (21,40;31,35;41,44) of different pairs forming a common annular element (21,40;12;48) which is in each case associated with both pairs.
3:
- Apparatus according to claim 1, in which in each case at least one of the annular elements (51) of the respective pair of annular elements is not completely closed when considered in the circumferential direction.
4:
- Apparatus according to claim 1, in which the cross section of at least one of the annular elements (12;50) of the respective pair of annular elements is not uniform (121;500) when considered in the circumferential direction.
5:
- Apparatus according to claim 1, in which the two annular elements (30,31;34,35) of the respective pair between which the air gap (33;37) is formed, in which air gap the magnetic field sensor (33;37) is arranged, are arranged coaxially at a radial distance (dr) from one another.
6:
- Apparatus according to claim 1, in which the two annular elements (40,41;44,45) of the respective pair between which the air gap (42;46) is formed are arranged coaxially at an axial distance (db) from one another.
7:
- Apparatus according to claim 1, in which two pairs of annular elements (30,31,34,35;40,41,44,45) are provided and are arranged at a predefined distance (da) from one another in the axial direction.
8:
- Apparatus according to claim 6, in which the two annular elements (41,44), which are arranged adjacent in the axial direction, of the two different pairs of annular elements are formed by a common annular element (48) associated with both pairs.
9:
- Linear motor having a stator (10) and a armature (11) which can be moved axially relative to the stator, and having an apparatus (2;3;4;5) for determination of the axial position of the armature (11) according to claim 1, in which linear motor the two annular elements (12;20,21;
- 30,31,34,35;40,41,44,45;48;50,51) surround the armature (11) of the linear motor.
10:
- Linear motor according to claim 9, having a magnetically permeable return-path tube (12), which surrounds at least the apparatus (2;3;4;5) for determination of the axial position of the armature (12).
11:
- Linear motor according to claim 10, in which the two annular elements (30,31;34,35) of the respective pair of annular elements of the apparatus for determination of the axial position of the armature are arranged at a radial distance (dr) from one another, and in which the radially outer annular element (31;35) of the respective pair of annular elements is formed by the magnetically permeable return-path tube (12).
12:
- Linear motor according to claim 11, in which the magnetic return-path tube (12) has a radial depression (120) in which the apparatus (3) for determination of the axial position of the armature is arranged, with the radially inner annular element (30;34) of the respective pair of annular elements in each case being arranged in the depression such that it is arranged essentially at the same height as the tube wall of the return-path tube (12) outside the depression (120).