Modular tubular linear switched reluctance machine

1. A tubular linear switched reluctance machine comprising:

a translator having a non-magnetic material body and ring segments of magnetic material axially separated from each other and provided on the body, the ring segments are distributed along an axial direction of the body, and

a stator arranged to electromagnetically interact with the translator, wherein the stator has a plurality of coaxially arranged annular modules, and a respective annular non-magnetic spacer arranged between each pair of subsequently arranged modules,

wherein each module has a stator pole pitch width in the axial direction, and an axial distance between midpoints of any pair of adjacent ring segments defines a translator pole pitch width, wherein the stator pole pitch width differs from the translator pole pitch width,

wherein each module has two teeth axially separated by a circumferential channel, wherein the stator pole pitch width is defined by an axial distance between midpoints of each pair of adjacent teeth of the respective module, and

wherein the stator pole pitch width is smaller than the translator pole pitch width.

2. The tubular linear switched reluctance machine as claimed in claim 1 , wherein the body is provided with a plurality of axially equally spaced circumferential recesses, wherein each ring segment is arranged in a respective circumferential recess.

3. The tubular linear switched reluctance machine as claimed in claim 2 , wherein an external surface of each ring segment is flush with an external surface of the body.

4. The tubular linear switched reluctance machine as claimed in claim 2 , wherein each module has a stator pole pitch width in the axial direction, and axial distance between midpoints of any pair of adjacent ring segments defines a translator pole pitch width, wherein the stator pole pitch width differs from the translator pole pitch width.

5. The tubular linear switched reluctance machine as claimed in claim 1 , wherein a ratio k s of the stator pole pitch width and the translator pole pitch width is less than 1.

6. The tubular linear switched reluctance machine as claimed in claim 1 , wherein a ratio k out between an outer axial length of one of the ring segments and the translator pole pitch width is less than or equal to 1.

7. The tubular linear switched reluctance machine as claimed in claim 6 , wherein a ratio k in between an inner axial length of one of the ring segments and the translator pole pitch width is less than the ratio k out .

8. The tubular linear switched reluctance machine as claimed in claim 1 , wherein a width of each spacer, in the axial direction, is dependent of the number of modules and a ratio k s of the stator pole pitch width and the translator pole pitch width.

9. The tubular linear switched reluctance machine as claimed in claim 8 , wherein the width of each spacer is further dependent of a tooth width of one of the teeth of the respective module.

10. The tubular linear switched reluctance machine as claimed in claim 8 , wherein the width of each spacer is determined by the formula

(

(

1

-

k

s

)

+

m

-

1

m

)

·

τ

translator

-

b

s

where m is the number of modules, τ translator is the translator pole pitch width, and b s is a tooth width of one the teeth of the respective module.

11. The tubular linear switched reluctance machine as claimed in claim 9 , wherein the width of each spacer is determined by the formula

(

(

1

-

k

s

)

+

m

-

1

m

)

·

τ

translator

-

b

s

where m is the number of modules, τ translator is the translator pole pitch width, and b s is the tooth width of said one of the teeth of the respective module.

12. The tubular linear switched reluctance machine as claimed in claim 1 , wherein each module includes a tubular magnetic core and a coil.

13. The tubular linear switched reluctance machine as claimed in claim 1 , wherein the tubular linear switched reluctance machine is a tubular linear switched reluctance motor.

14. The tubular linear switched reluctance machine as claimed in claim 1 , wherein the stator is arranged to receive the translator or the translator is arranged to receive the stator.

15. A tubular linear switched reluctance machine comprising:

a translator having a non-magnetic material body and ring segments of magnetic material axially separated from each other and provided on the body, the ring segments are distributed along an axial direction of the body, and

a stator arranged to electromagnetically interact with the translator, wherein the stator has a plurality of coaxially arranged annular modules and a plurality of annular non-magnetic spacers, wherein each pair of subsequently arranged module is separated by one of the annular non-magnetic spacers,

wherein each module has a stator pole pitch width in the axial direction, and an axial distance between midpoints of any pair of adjacent ring segments defines a translator pole pitch width, wherein the stator pole pitch width differs from the translator pole pitch width,

wherein each module has two teeth axially separated by a circumferential channel, wherein the stator pole pitch width is defined by an axial distance between midpoints of each pair of adjacent teeth of the respective module, and

wherein the stator pole pitch width is smaller than the translator pole pitch width.