Electrically operated linear motor with integrated flexure spring and circuit for use in reciprocating compressor

• US 6,129,527 A
• Filed: 04/16/1999
• Issued: 10/10/2000
• Est. Priority Date: 04/16/1999
• Status: Active Grant

• Current Assignee: Cobham Mission Systems Davenport Lss Inc.
• Original Assignee: Litton Systems Incorporated
• Inventors: Nelson, Arthur Randall, Donahoe, Thomas S.
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): FASTOVSKY, LEONID M
• Application Number:
  US09/292,984
• Time in Patent Office: 543 Days
• Field of Search: 417/416, 417/418, 417/417, 417/383, 417/45, 310/15, 62/228.1, 62/228.6, 318/135
• US Class Current: 417/416
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: H02K 2211/03 Machines characterised by circuit boards, e.g. pcb
• CPC Class Codes: H02K 33/18 with coil systems moving upon intermittent or reversed energisation thereof by interaction with a fixed field system, e.g. permanent magnets
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132

Abstract

A reciprocating compressor includes an electric motor having fixed and moveable components within a housing for reciprocating a moveable assembly, to compress a working fluid within a variable volume compression chamber within the housing. An integrated flexure spring and circuit connected between the housing and the moveable assembly axially and radially centers the moveable assembly within the housing, and additionally, supplies an electric current to a moveable current coil of the electric motor associated with the moveable assembly. The moveable assembly is axially reciprocated against a restoring force of the integrated flexure spring and circuit responsive to an axial force exerted on the moveable assembly by the electric motor when the electric current is supplied to the moveable current coil via the integrated flexure spring and circuit.

Claims

1. A reciprocating compressor adapted to be responsive to an electric current applied to a fixed terminal of the reciprocating compressor, comprising:

a housing;

a reciprocating electric motor including components fixed within said housing and moveable components connected to reciprocate a moveable assembly coacting with at least one variable volume chamber formed within said housing to compress a working fluid supplied to said chamber;

a resilient spring connected between said housing and said moveable assembly to resiliently suspend and center said moveable assembly and said moveable components within said housing; and

,

a flexible, electrically conductive printed circuit fixed to said resilient spring to supply the electric current applied to the fixed terminal to an electrical terminal of the electric motor.

2. The reciprocating compressor of claim 1, wherein:

said resilient spring is constructed and arranged to center said moveable assembly within said housing in radial and axial directions, and

said moveable assembly is displaced from an initial position in first and second opposing axial directions against a restoring force of said resilient spring responsive to an axial force exerted on said moveable assembly by said electric motor when the electric current is supplied to the fixed terminal.

3. The reciprocating compressor of claim 2, wherein said resilient spring includes a substantially planar, resilient flexure spring extending across said housing in said radial direction, and wherein said printed circuit is electrically coupled between the fixed terminal and said electrical terminal of said electric motor.

4. The reciprocating compressor of claim 3, wherein said resilient spring includes:

an outer rim fixed to a periphery of said housing,

an inner hub fixed to an end of said moveable assembly, and

a resilient support member coupled between said outer rim and said inner hub, said resilient support member providing said restoring force when said inner hub and said moveable assembly fixed thereto are displaced in said first and second axial directions.

5. The reciprocating compressor of claim 4, wherein said printed circuit is electrically isolated from said resilient spring.

6. The reciprocating compressor of claim 5, wherein said printed circuit is applied to an electrically insulating surface of said resilient spring.

7. The reciprocating compressor of claim 6, wherein said printed circuit includes:

an outer terminal portion coincident with said outer rim and electrically coupled to the fixed terminal,

an inner terminal portion, and

a portion coincident with said resilient support member and connecting said inner and outer terminal portions.

8. The reciprocating compressor of claim 7, wherein said outer terminal portion and the fixed terminal are coincident, and said inner terminal portion and said inner hub are coincident.

9. The reciprocating compressor of claim 8, wherein said resilient support member includes first and second resilient spring arms coupled between said outer rim and said inner hub, and said printed circuit traverses a length of said first resilient spring arm.

10. The reciprocating compressor of claim 4, wherein said printed circuit includes:

an outer terminal portion coincident with the outer rim of said resilient spring and electrically coupled to the fixed terminal,

an inner terminal portion, and

a portion connecting said outer terminal portion and said inner terminal portion.

11. The reciprocating compressor of claim 2, wherein said electric motor includes

a current coil adapted to be displaced with said moveable assembly, said current coil having an electrical terminal electrically coupled to said printed circuit of said resilient spring, and

a magnet assembly fixed within said housing, said axial force resulting from a magnetic interaction induced between said magnet assembly and said current coil when the electric current is supplied to the fixed terminal.

12. The reciprocating compressor of claim 11, wherein said current coil includes first and second axially spaced current coil windings, and said magnet assembly includes first and second axially spaced ring magnet assemblies for respective magnetic interaction with said first and second current coil windings, said first and second ring magnet assemblies being respectively magnetically polarized in opposing radial directions.

13. The reciprocating compressor of claim 11, wherein said moveable assembly includes:

a cylinder extending along an axis of said housing, said cylinder having an

end fixed to said resilient spring, and

said current coil, said current coil at least partially surrounding said cylinder.

14. The reciprocating compressor of claim 9, wherein an electrical lead is coupled between said electrical terminal of said motor and said inner terminal portion of said printed circuit applied to said resilient spring.

15. The reciprocating compressor of claim 14, wherein first and second flexible, electrically conductive printed circuits are respectively applied to electrically insulating surfaces of said first and second spring arms to electrically isolate said first and second printed circuits from said resilient spring and each other, said first and second printed circuits being respectively, electrically coupled between first and second fixed terminals of said housing and respective first and second electrical terminals of said motor to supply the electric current applied to said first and second fixed terminals to said first and second electrical terminals of said motor.

16. The reciprocating compressor of claim 13, further including a piston fixed within said housing, said piston extending along said axis of said housing and within said cylinder to form said at least one variable volume chamber between said piston and said cylinder, said piston having axial and radial through bores therein, said axial and radial through bores being in fluid communication with each other and with said chamber, whereby the working fluid is displaced from said chamber and through said axial and transverse through bores responsive to a relative axial displacement between said cylinder and said piston.

17. The reciprocating compressor of claim 11, wherein said moveable assembly includes a piston having a portion thereof fixed to said resilient member and suspended thereby to extend along said axis of said housing, said piston having a free end for coacting with said variable volume chamber within said housing, said housing including an exit through bore in fluid communication with said chamber, whereby said working fluid is displaced from said chamber and through said exit through bore responsive to said axial displacement.

18. The reciprocating compressor of claim 1, wherein an opposing pair of said reciprocating electric motors, an associated opposing pair of said resilient springs, and an associated pair of said flexible, electrically conductive printed circuits disposed within said housing cooperate to compress the working fluid within an associated pair of said at least one variable volume chambers, responsive to an application of the electric current to said pair of said electric motors through said pair of said printed circuits.

19. A method of operating a reciprocating compressor for compressing a working fluid, the reciprocating compressor including a housing and a moveable assembly reciprocated with an electric motor disposed in said housing, comprising the steps of:

positioning and centering said moveable assembly radially within said housing with a resilient spring; and

supplying an electric current to said electric motor through a flexible, electrically conductive printed circuit fixed to said resilient spring.

20. The method of claim 19, wherein the positioning step further includes the step of positioning and centering said moveable assembly axially within said housing with said resilient spring.

21. The method of claim 19, further including the step of displacing said moveable assembly from an initial position in first and second opposing axial directions against a restoring force of said resilient spring responsive to said step of supplying.

22. The method of claim 20, wherein the step of supplying includes the further step of supplying an electric current to said electric motor through a pair of flexible, electrically conductive printed circuits fixed to and electrically isolated from said resilient spring.

23. An integrated flexure spring and circuit for use in a reciprocating compressor, comprising:

a substantially planar, resilient flexure spring having an outer rim, an inner hub and a resilient support member coupled between said outer rim and said inner hub; and

a flexible, electrically conductive printed circuit fixed to said flexure spring.

24. The integrated flexure spring and circuit of claim 23, wherein said inner hub, said resilient support member and said printed circuit are adapted to be displaced from a planar rest position in first and second opposing axial directions against a restoring force of said resilient support member.

25. The device as recited in claim 24, wherein said resilient support member includes at least two resilient support arms resiliently coupling said inner hub to said outer rim.

26. The device as recited in claim 25, wherein said at least two resilient support arms are circumferentially and radially directed between said outer rim and said inner hub.

27. The device as recited in claim 25, wherein said printed circuit includes an outer terminal portion proximate said outer rim, an inner terminal portion proximate said inner hub, and a portion traversing at least one of said plurality of resilient support arms and connecting said outer and inner terminal portions.

28. The device as recited in claim 25, wherein at least two flexible, electrically conductive printed circuits are respectively applied to electrically insulating surfaces of said at least two resilient support arms to electrically isolate said printed circuits from said flexure spring and each other.