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| Vacuum actuated tubular blood pumping device with active values and application of the same |
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Reciprocating linear motor
| Details |
Inventors: Goldowsky, Michael P.;
Assignee: The United States of America as represented by the Administrator of the (Washington, DC)
Primary Examiner: Duggan; Donovan F.
Assistant Examiner:
Attorney, Agent or Firm: Tresansky; John O., Manning; John R., Sheinbein; Sol
A reciprocating linear motor (10) is formed with a pair of ring-shaped permanent magnets (50, 52) having opposite radial polarizations, held axially apart by a non-magnetic yoke (20), which serves as an axially displaceable armature assembly (14). A pair of annularly wound coils (30, 32) having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core (24) in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils (36, 38) serially coupled together in mutual opposition and an inner cylindrical core (26) positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils. |
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DETAILED DESCRIPTION OF THE INVENTION Refer now to the drawings and, in particular, to FIG.
1 which illustrates an axially symmetric reciprocating linear motor 10 according to this invention.
The motor is formed by a stationary assembly 12 and a reciprocating armature assembly 14 coaxially positioned around a central shaft 16 disposed inside a cylindrical housing 18.
The housing serves as a rigid frame supporting the stationary assembly.
One end of the armature assembly 14 is joined to the shaft 16 by a yoke 20.
In operation, electromagnetic interaction between the stationary and armature assemblies gives rise to a force directed along the longitudinal axis 22 of the motor that causes a limited axial displacement of the armature assembly 14 and shaft 16 relative to stationary assembly 12 and housing 18.
If the housing 18 is stationary, the axial displacement will be confined to linear movement of the armature assembly and may be used to perform work.
The stationary assembly 12 includes an outer core 24 and an inner core 26, both of which are formed of a ferromagnetic material.
The cores are held coaxially aligned and centered upon axis 22 by a connecting plate 27 of a non-ferromagnetic material attached to one end of each core.
Radial separation between cores 24, 26 provides a relatively large cylindrical air gap 28 of uniform axial width.
The stationary assembly also includes an outer pair of annularly wound coils 30, 32 positioned within air gap 28 against the interior circumferential surface 34 of the outer core 24.
The axial length, diameter, number of turns and wire gauge of coils 30, 32 are identical.
Coils 30 and 32 are coupled together in series opposition.
An inner pair of annularly wound coils 36, 38 are also positioned within air gaps 28.
The inner pair of coils, also coupled together in series opposition, are radially separated from the outer pair and are set against the exterior circumferential surface 40 of the inner core 26.
Coils 36 and 38 also have identical lengths, diameter, numbers of turns, and wire gauges
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Heart Surgery 
