OPERATION OF MAGNETOSTRICTIVE APPARATUS

• US 3,753,058 A
• Filed: 12/16/1971
• Issued: 08/14/1973
• Est. Priority Date: 06/22/1970
• Status: Expired due to Term

• Current Assignee: Alden P. Edson
• Original Assignee: Alden P. Edson
• Inventors: Edson, Alden P.
• Primary Examiner(s): Duggan, D. F.
• Application Number:
  US05/208,822
• Time in Patent Office: 607 Days
• Field of Search: 310/26 318/118,129
• US Class Current: 318/118
• CPC Class Codes: B06B 1/08 operating with magnetostriction magnetostrictive devices per se H10N30/00
• CPC Class Codes: H10N 35/00 Magnetostrictive devices integrated devices or assemblies of multiple devices H10N39/00

Abstract

Electromechanical transducer core containing magnetostrictive material is energized by two mutually transverse electromagnetic fields controlled to oscillate the direction of magnetization cyclically and vibrate the core by longitudinal and transverse magnetostriction; electrically controlled change of resonant frequency is obtained with controlled variation of magnetization intensity.

Claims

1. A process for magnetostrictively converting electrical power to vibratory mechanical power exerted along a desired longitudinal axis of mechanical power output in a magnetostrictive core and for altering the resonant frequency of the core comprising applying two mutually transverse electromagnetic fields to a core containing bilinear magnetostrictive material characterized by a substantial delta-E effect and cyclically fluctuating the flux density of at least one of the two electromagnetic fields to magnetize the core with a cyclically varying resultant magnetic field having an angularly oscillating axis of magnetization oscillating within an angular range of up to 90* from, and not crossing, the axis of desired power output and characterizing the core with a first resonant frequency, to thereby magnetostrictively vibrate the core longitudinally, and then electrically changing the flux density of at least one of the two applied fields to change the average intensity of the cyclically varying resultant magnetic field and thereby alter the resonant frequency of the core and characterize the core with a second resonant frequency.

2. A process as set forth in claim 1 wherein one of the two applied fields is a constant field, the resultant intensity of magnetization is maintained greater than zero and less than the saturation limit of the magnetostrictive material and the average intensity of the resultant magnetic field is changed by changing the flux density of the constant field.

3. A process as set forth in claim 1 wherein the two fields intersect mutually perpendicularly within the core, both of the two fields are cyclically fluctuated 180* out-of-phase with each other, the peak intensities of the two fluctuating fields are maintained equal in magnitude and the average intensity of magnetization is changed by changing the amplitude of the cyclic fluctuation of the two applied fields equally and maintaining the peak intensities of the two fields to not exceed the magnetic saturation limit of the core material.

4. A process as set forth in claim 1 wherein the magnetic axis is oscillated within an angle of about 25* to about 65* from the direction of desired mechanical power output.

5. A process as set forth in claim 1 wherein the magnetic axis is oscillated within an angle of about 70* to 90* from the direction of desired mechanical power output.

6. A process as set forth in claim 1 wherein the flux density in the core is cyclically varied within a range of 5 to 50 percent of the saturation flux density of the core material during one period of operation and wherein during another period of operation of the process the flux density is cyclically varied within a range of 50 to 95 percent of the saturation flux density.

7. A process as set forth in claim 1 wherein the oscillating resultant field is cycled at the first resonant frequency when the core is characterized with the first resonant frequency and wherein the cycling frequency of the resultant field is changed to the second resonant frequency when the core is characterized with the second resonant frequency.

8. A magnetostrictive transducer for converting electrical power to vibratory mechanical power and adapted for exerting a major proportion of said vibratory mechanical power by longitudinal vibration directly along an axis of desired power output comprising a core containing bilinear magnetostrictive material characterized by a delta-E effect of magnitude sufficient to enable changing the resonant frequency of the core, said core extending along the axis of desired power output, a first electrically conductive coil adapted to be electromagnetically coupled with the core when electric current is passed through the coil and to thereby produce a first electromagnetic field having flux directed along the axis of desired power output and a second electrically conductive coil adapted to be electromagnetically coupled with the core when electric current is passed through said second coil and to thereby produce a second electromagnetic field having flux intersecting the core in a direction transverse to the direction of flux intersecting the core from the first coil.

9. A transducer as set forth in claim 8 wherein the bilinear magnetostrictive material is characterized by a delta-E effect of at least 5 percent.

10. A transducer as set forth in claim 8 wherein the magnetostrictive material is selected from the group consisting of nickel, nickel-cobalt alloys containing about 4 to 5 percent cobalt with balance nickel, vanadium-cobalt-iron alloys containing about 2 percent vanadium, 49 percent cobalt and 49 percent iron, nickel-iron alloys containing about 45 percent nickel and 55 percent iron and magnetostrictive ferrites characterized by a compositional formula of (Ni0.90Zn0.10)0.876Co0.024Cu0.010Fe2O4, Mn0.7Fe0.4Fe2O4 or Ni0.88Cu0.11Co0.01Fe2O4.

11. A magnetostrictive transducer comprising a hollow annular cylindrical core containing bilinear magnetostrictive material characterized by a delta-E effect of magnitude sufficient to enable changing the resonant frequency of the core, said core having a cylindrical configuration with a central opening extending axially through the cylinder and a continuous annular cavity substantially enclosed within the cylinder and extending around the central opening, an electrically conductive exterior toroidal coil wound toroidally through the central opening and around the exterior of the cylinder and an electrically conductive interior circumferential coil wound annularly within the cavity and having electrically conductive leads extending to the exterior of the cavity.