Integral motor propulsor unit for water vehicles with plural electric motors driving a single propeller

• US 5,252,875 A
• Filed: 03/28/1991
• Issued: 10/12/1993
• Est. Priority Date: 08/23/1990
• Status: Expired due to Term

• Current Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Drake, James A., Veronesi, Luciano
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): LABALLE, CLAYTON E
• Application Number:
  US07/676,400
• Time in Patent Office: 929 Days
• Field of Search: 440/6, 440/38, 417/356, 310/67 R, 310/62, 310/63, 310/87, 310/112, 310/114, 310/156
• US Class Current: 310/114
• CPC Class Codes: B63H 1/16 having a shrouding ring attached to blades
• CPC Class Codes: B63H 2023/005 using a drive acting on the periphery of a rotating propulsive element, e.g. on a dented circumferential ring on a propeller, or a propeller acting as rotor of an electric motor
• CPC Class Codes: B63H 23/24 electric dynamo-electric machines H02K
• CPC Class Codes: B63H 5/14 characterised by being mounted in non-rotating ducts or rings, e.g. adjustable for steering purpose shrouding ring attached to blades B63H1/16; jet propulsion B63H11/00
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 21/46 Motors having additional short-circuited winding for starting as an asynchronous motor
• CPC Class Codes: H02K 5/1285 of the submersible type
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132
• CPC Class Codes: H02K 7/086 radially supporting the rotor around a fixed spindle; radially supporting the rotor directly H02K7/09 takes precedence
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06

Abstract

The submersible propulsor unit of the invention comprises a cylindrical shroud having a water inlet and a water outlet, a propeller having a hub rotatably mounted within the shroud on a shaft, and an electric motor for driving the propeller that includes a rotor mounted around the periphery of the propeller, and a stator circumscribing the shroud, and a bearing assembly that includes means for circulating ambient water around the bearing surfaces to both lubricate and cool them. A stationary cover is detachably secured over the bearing assembly on the water inlet end of the shaft to provide easy access to the bearings in the bearing assembly The vane members that concentrically mount the shaft within the interior of the shroud are, in one embodiment, all connected on the downstream side of the propeller to reduce the cavitation and resulting noise when the propeller rotates. The magnetization of the rotor is provided by a plurality of permanent magnets for both improved efficiency, and lower noise. A squirrel cage structure formed from damper bars and conductive wedges is integrated over the magnets of the rotor both to assist in the starting of the motor, as well as to insulate the magnets from harmonic currents that could act to de-magnetize them. In one embodiment, the propulsor unit has a single propeller driven by two identical side-by-side motor assemblies. This arrangement provides added reliability while retaining mechanical simplicity and low cost and weight as compared with a multipropeller propulsor unit.

Claims

1. A submersible propulsor unit, comprising:

a shroud having a water inlet and a water outlet;

a propeller means having a unitary hub and a single blade assembly rotatably mounted within said shroud on a shaft;

at least two independently operable electric motors for driving said propeller means, each electric motor including a rotor mounted around the periphery of the single blade assembly of said propeller means and a stator mounted within said shroud and spaced away from but magnetically coupled to said rotor; and

a bearing assembly having at least one bearing surface disposed between the hub of said propeller means and said shaft.

2. A submersible propulsor unit as defined in claim 1, further comprising a plurality of vane members connected between said shroud and said shaft for supporting said shaft along the axis of rotation of said propeller means, wherein at least one set of said vane members is connected to a portion of said shaft disposed between said hub and the outlet end of said shroud.

3. A submersible propulsor unit as defined in claim 2, wherein said bearing assembly includes both a thrust bearing and a radial bearing disposed between said shaft and said hub of said propeller means.

4. A submersible propulsor unit as defined in claim 3, wherein said shaft has an end that faces the inlet end of said shroud, and said hub of the propeller means is connected to said thrust bearing which transmits substantially all of the thrust said propeller means generates to said shaft end.

5. A submersible propulsor unit as defined in claim 2, wherein another set of vane members is connected to a portion of said shaft between said hub and the inlet end of said shroud.

6. A submersible propulsor unit as defined in claim 1, wherein said rotor of each motor includes permanent magnets for increasing the minimum distance required between the rotor and stator for efficient magnetic coupling and thereby reducing both drag losses and the noise generated by the propeller means.

7. A submersible propulsor unit as defined in claim 6, wherein said rotor includes damper bar means for protecting said magnets from spurious currents.

8. A submersible propulsor unit as defined in claim 1, wherein each rotor is fixedly secured with respect to each other rotor around the periphery of said propeller means in a spaced relationship.

9. A submersible propulsor unit as defined in claim 1, wherein each motor comprises independently operational means for connection to a power source, whereby shutdown or malfunction of one motor will not affect the functioning of another motor.

10. A submersible propulsor unit as defined in claim 1, wherein said at least two motors are identical to each other.

11. A submersible propulsor unit as defined in claim 1, wherein said propeller means is centered in an axial direction of the propulsor unit between said at least two motors.

12. A submersible propulsor unit as defined in claim 1, wherein said at least two motors are physically isolated from each other.

13. A submersible propulsor unit as defined in claim 1, wherein said at least two motors consists of two motors.

14. A submersible propulsor unit as defined in claim 1, further comprising attachment means for attaching the propulsor unit to a water vessel as a primary drive unit.

15. A submersible propulsor unit as defined in claim 14, wherein said propulsor unit is configured to form a tail portion of a submarine.

16. A submersible propulsor unit as defined in claim 1, wherein said hub and shaft are tapered inwardly from the water inlet to the water outlet.

17. A submersible propulsor unit, comprising:

a shroud having a water inlet and a water outlet;

a single propeller mans having a unitary hub and a single blade assembly rotatably mounted within said shroud on a shaft;

two electric motors for driving only said single propeller means in order to enhance the operational reliability of the propulsor unit, each electric motor including a rotor mounted around the periphery of the single blade assembly of said single propeller means, the rotors of each of said motors being independently fixedly secured around separate portions of said periphery in a spaced apart relationship, and each motor having a stator mounted within siad shroud and spaced away from but magnetically coupled to its respective rotor, wherein each motor includes independently operational means for connection to a power source such that the shutdown or malfunction of one motor will not affect the functioning of another motor, and

a bearing assembly having at least one bearing surface disposed between the hub of said propeller means and said shaft.