Electromechanical generator for converting mechanical vibrational energy into electrical energy

• US 7,586,220 B2
• Filed: 10/31/2007
• Issued: 09/08/2009
• Est. Priority Date: 04/27/2007
• Status: Active Grant

• Current Assignee: Hitachi Rail Ltd. (Hitachi, Ltd.)
• Original Assignee: Perpetuum, Ltd. (Hitachi, Ltd.)
• Inventors: Roberts, Stephen
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US11/932,578
• Publication Number:
  US 20080265692A1
• Time in Patent Office: 678 Days
• Field of Search: 310/15, 310/17, 310 22- 24, 310 28- 30, 310/36, 310/38, 290/1.R, 367/185, 367/187
• US Class Current: 310/15
• CPC Class Codes: H02K 1/34 Reciprocating, oscillating or vibrating parts of the magnetic circuit
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems

Abstract

An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a housing, an electrically conductive coil assembly fixedly mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extending inwardly of the radially inner side for fixing the coil assembly in a fixed position in the housing, a magnetic core assembly movably mounted in the housing for linear vibrational motion along an axis, and a biasing device mounted between the housing and the magnetic core assembly to bias the magnetic core assembly in opposed directions along the axis towards a central position, wherein the magnetic core assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnetic core assembly having a gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.

Claims

1. An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a housing, an electrically conductive coil assembly fixedly mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extending inwardly of the radially inner side for fixing the coil assembly in a fixed position in the housing, a magnetic core assembly movably mounted in the housing for linear vibrational motion along an axis, and a biasing device mounted between the housing and the magnetic core assembly to bias the magnetic core assembly in opposed directions along the axis towards a central position, wherein the magnetic core assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnetic core assembly having a gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.

2. An electromechanical generator according to claim 1 wherein the biasing device comprises a pair of springs, each being located at a respective end of the magnetic core assembly.

3. An electromechanical generator according to claim 2 wherein the springs comprise plate springs.

4. An electromechanical generator according to claim 1 wherein the magnetic core assembly comprises two opposed magnetic circuits spaced along the axis.

5. An electromechanical generator according to claim 1 wherein the magnetic core assembly comprises a pair of magnets spaced along the axis, poles of the magnets having a first common polarity facing towards each other, and poles of the magnets facing away from each other being of a second common polarity and being coupled to a common ferromagnetic body located radially outwardly of the magnets relative to the axis.

6. An electromechanical generator according to claim 5 wherein the common ferromagnetic body is tubular and has radially inwardly extending arms at each end thereof, each arm mounting a respective magnet thereon.

7. An electromechanical generator according to claim 5 wherein the common ferromagnetic body comprises a radially outer and upper and lower portions of the magnetic core assembly and the magnets comprise the radially inner portion.

8. An electromechanical generator according to claim 1 wherein the mount for the coil assembly comprises an annular coil support which has a central mounting portion that extends radially inwardly from a central pail of the coil assembly and is mounted on a central body that is fixed along the axis.

9. An electromechanical generator according to claim 8 wherein the mounting portion defines an annular recess in which is received circuitry for electrically conditioning the electrical output of the coil assembly.

10. An electromechanical generator according to claim 9 wherein the circuitry is encapsulated within the annular recess by a sealing material, which seals and protects the circuitry against undesired environmental influences.

11. An electromechanical generator according to claim 1 wherein the mount for the coil assembly comprises a moulded plastic body that encapsulates the coil, the moulded plastic body including an integral central body that is fixed along the axis and is fitted to a lid and a base of the housing.

12. An electromechanical generator according to claim 11 wherein the integral central body encapsulates an elongate stiffening member extending along the axis.

13. An electromechanical generator according to claim 11 wherein the moulded plastic body encapsulates circuitry for electrically conditioning the electrical output of the coil assembly.

14. An electromechanical generator according to claim 11 wherein the moulded plastic body encapsulates electrical wires extending from the coil assembly and further comprising connecting pins connected to the wires for electrical connection to an external electrical circuit, the connecting pins extending from an external surface of the moulded plastic body that is exposed at an exterior of the housing.

15. An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a fixed electrically conductive coil assembly and a magnet assembly movably mounted for linear vibrational motion along an axis, wherein the magnet assembly comprises a pair of magnets spaced along the axis, poles of the magnets having a first common polarity facing towards each other and separated by a gap, and poles of the magnets facing away from each other being of a second common polarity and being coupled to a common ferromagnetic body located radially outwardly of the magnets relative to the axis, and a biasing device for biasing the magnet assembly, comprising the pair of magnets and the ferromagnetic body coupled thereto, in opposed directions along the axis towards a central position, wherein the magnet assembly comprises two opposed magnetic circuits spaced along the axis, each magnetic circuit being associated with a respective portion of the coil assembly.

16. An electromechanical generator according to claim 15 further comprising a housing, wherein the electrically conductive coil assembly is fixedly mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extends inwardly of the radially inner side for fixing the coil assembly in a fixed position in the housing, the magnet assembly being movably mounted in the housing, and the biasing device is mounted between the housing and the magnet assembly, wherein the magnet assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnet assembly having the gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.

17. An electromechanical generator according to claim 15 wherein the biasing device comprises a pair of springs, each being located at a respective end of the magnet assembly.

18. An electromechanical generator according to claim 17 wherein the springs comprise plate springs.

19. An electromechanical generator according to claim 15 wherein the magnet assembly is rotationally symmetric and has a substantially C-shaped cross-section defining the gap.

20. An electromechanical generator according to claim 15 wherein the common ferromagnetic body is tubular and has radially inwardly extending arms at each end thereof, each arm mounting a respective magnet thereon.

21. An electromechanical generator according to claim 15 wherein the common ferromagnetic body comprises radially outer and upper and lower portions of the magnet assembly and the magnets comprise a radially inner portion of the magnet assembly.

22. An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a fixed electrically conductive coil assembly and a magnet assembly movably mounted for linear vibrational motion along an axis, and a biasing device for biasing the magnet assembly in opposed directions along the axis towards a central position, wherein the magnet assembly is rotationally symmetric and has a substantially C-shaped cross-section enclosing an annular cavity, having a gap on the inner radius thereof in which cavity the coil assembly is disposed.

23. An electromechanical generator according to claim 22 wherein the magnet assembly comprises two opposed magnetic circuits spaced along the axis, each magnetic circuit being associated with a respective portion of the coil assembly.

24. An electromechanical generator according to claim 22 further comprising a housing, wherein the electrically conductive coil assembly is fixedly mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extends inwardly of the radially inner side for fixing the coil assembly in a fixed position in the housing, the magnet assembly being movably mounted in the housing, and the biasing device is mounted between the housing and the magnet assembly, wherein the magnet assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnet assembly having a gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.

25. An electromechanical generator according to claim 22 wherein the biasing device comprises a pair of springs, each being located at a respective end of the magnet assembly.