Position sensor

1. A position sensor for determining a linear position in a sensing direction, comprising:

a first sensor part and a second sensor part moveable with respect to each other,

wherein the first sensor part comprises

an annular magnet with its magnet axis coinciding with the sensing direction and generating a magnetic field with a distribution axially symmetric along the sensing direction, and

a magnetic field sensor positioned at a first distance from the annular magnet on the magnet axis,

wherein the second sensor part comprises a flux shaper moveable through the annular magnet along the sensing direction between a first and a second position, in the first position the flux shaper being substantially at the first distance from the magnetic field sensor, in the second position the flux shaper being substantially at a second distance from the magnetic field sensor,

the flux shaper being arranged to influence the magnetic field in a space between the annular magnet and the magnetic field sensor.

2. The position sensor according to claim 1 , wherein the annular magnet has an inner diameter d 1 and the flux shaper has a maximum outer diameter d 2 , wherein the difference between inner diameter d 1 and maximum outer diameter d 2 is at least 1 mm.

3. The position sensor according to claim 1 , wherein the flux shaper is an end part of an actuator rod.

4. The position sensor according to claim 1 , further comprising a mounting disk connected to a second end of the flux shaper distal to the magnetic field sensor, the mounting disk comprising a main surface which is substantially perpendicular to the sensing direction.

5. The position sensor according to claim 1 , further comprising a magnetic shielding element near the magnetic field sensor.

6. The position sensor according to claim 5 , wherein the magnetic shielding element is a cup shaped element shielding a space between the annular magnet and magnetic field sensor in circumferential direction.

7. The position sensor according to claim 1 , wherein said annular magnet is a permanent magnet.

8. The position sensor according to claim 1 , wherein the annular magnet is an electromagnet.

9. The position sensor according to claim 1 , wherein said flux shaper is manufactured from soft magnetic material.

10. The position sensor according to claim 1 , wherein the flux shaper is an elongated rod with a predetermined radial profile.

11. The position sensor according to claim 10 , wherein the predetermined radial profile comprises a stepped profile.

12. The position sensor according to claim 1 , wherein the position sensor comprises a sensor housing formed as a single molded part.

13. The position sensor according to claim 1 , wherein the position sensor comprises a sensor housing including a first part for mounting the magnetic field sensor and a second part for holding the annular magnet at the first distance from the magnetic field sensor.

14. An actuator for providing a linear movement to an actuator element, comprising a position sensor according to claim 1 , wherein the second sensor part is connected to the actuator element.

15. An actuator according to claim 14 , wherein the second sensor part is connected to the actuator element using a coupling allowing mutual movement in a direction different from the sensing direction.

16. The position sensor as in claim 7 , wherein the permanent magnet comprises AlNiCo.

17. The position sensor as in claim 7 , wherein the magnetic material comprises carbon steel.