Externally tuned vibration absorber

• US 4,694,650 A
• Filed: 07/28/1986
• Issued: 09/22/1987
• Est. Priority Date: 07/28/1986
• Status: Expired due to Fees

• Current Assignee: Mechanical Technology Incorporated
• Original Assignee: Mechanical Technology Incorporated
• Inventors: Vincent, Ronald J.
• Primary Examiner(s): Husar, Stephen F.
• Application Number:
  US06/889,697
• Time in Patent Office: 421 Days
• Field of Search: 60/517, 60/520, 60/525, 62/6, 188/379, 188/380
• US Class Current: 60/520
• CPC Class Codes: F02G 1/04 of closed-cycle type
• CPC Class Codes: F02G 1/0435 the engine being of the free piston type
• CPC Class Codes: F02G 1/0535 Seals or sealing arrangements
• CPC Class Codes: F02G 2243/50 having resonance tubes
• CPC Class Codes: F02G 2253/03 Stem seals
• CPC Class Codes: F16F 7/104 the inertia member being resiliently mounted F16F7/1022 takes precedence

Abstract

A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

Claims

1. In a hydraulic apparatus of the type having a housing filled with a relatively incompressible fluid, said housing being secured to a prime mover and containing diaphragm means for converting vibratory energy transmitted from the prime mover into pressure waves within the fluid for oscillating a movable element along a linear path of motion, the improvement comprising at least one vibratory absorber unit attached to the outside of the housing for absorbing vibrational energy resulting from the oscillation of the movable element that includes a spring means and an absorber mass affixed to the spring means for reciprocal movement parallel with the path of travel of said movable element, and means to adjust the resonant frequency of the absorber means whereby the resonant frequency of the absorber means can be matched to the frequency range of the pressure waves.

2. The improvement of claim 1 wherein said diaphragm means includes a first diaphragm adjacent the prime mover on one side of the movable element and a second diaphragm and a gas spring on the opposite side of the movable element and a pair of absorber units secured on opposite sides of said housing between the two diaphragms.

3. The improvement of claim 1 wherein said diaphragm means includes a first diaphragm adjacent the prime mover on one side of the movable element and a second diaphragm and a gas spring on the opposite side of the movable element and said spring means mounted on said housing beneath the gas spring with the absorber mass being disposed generally on the axis of the housing.

4. The improvement of claim 2 wherein each absorber unit further includes a pair of spaced spring packages each secured to the housing and said absorber mass being suspended between the packages, each package further containing a plurality of spacer strips interleaved between leaf springs with the strips and leaf springs being stacked parallel with the path of motion of said movable element.

5. The improvement of claim 1 wherein said absorber mass is disposed between two gas springs.

6. In a hydraulic drive apparatus of the type having a housing filled with a relatively incompressible fluid, said housing being secured to a Stirling engine and further including a cylinder for separating the housing into two volumes, a first diaphragm in a volume adjacent the engine and a second diaphragm and an operably associated gas spring in said second volume which coact to convert vibratory energy transmitted from the engine into fluid pressure waves for oscillating a movable element along the axis of said cylinder, the improvement comprising a plurality of external vibratory absorber units spaced about the outside of the housing for absorbing vibrational energy generated by the movable means, said absorber units each including a mass suspended between a pair of resilient spring packages which are secured to the housing to permit the mass to reciprocate along a path of travel that is parallel with the axis of said cylinder.

7. The improvement of claim 6 wherein each spring means includes a spring package formed of a plurality of leaf springs that are stacked together in a direction perpendicular with the axis of the cylinder and said absorber mass is suspended between the packages for movement parallel with the said axis.

8. The improvement of claim 7 wherein each spring pack further includes a plurality of spacer strips interleaved between the leaf springs.

9. The improvement of claim 7 wherein each leaf spring has a bottom section secured to the housing, a top section secured to the absorber mass and a mid-section, the top and bottom sections being of the same width and the mid-section being narrower than the top and bottom sections.

10. The improvement of claim 9 wherein the width of the mid-section is substantially one-third the width of the other two sections.

11. The improvement of claim 9 wherein the leaf springs are arcuately tapered between the top and bottom sections.

12. The improvement of claim 6 that further includes weight means removably secured to the absorber mass to selectively adjust the mass of the absorber unit and thus its natural frequency.

13. The improvement of claim 12 wherein the prime mover creates pressure waves of a predetermined frequency in the fluid and the natural frequency of the absorber units is adjusted to about match the predetermined frequency.

14. The improvement of claim 13 wherein said natural frequency is within 4 Hz of the predetermined frequency.

15. The improvement of claim 6 wherein said movable element is connected to load to produce mechanical work.

16. A hydraulic drive for converting vibratory energy to work that includes

a prime mover for generating vibratory enegy that is attached to a housing filled with a relatively incompressible fluid to form a system,

said housing being divided into two volumes by a cylinder movably containing a piston,

means to connect the piston to a load,

18. The drive of claim 16 wherein the absorber is centrally positioned upon the axis of the housing that is perpendicular with the axis of the cylinder.

19. The drive of claim 16 wherein the absorber mass is slidably retained in a low friction means.

20. The drive of claim 16 wherein said spring means includes a mechanical spring acting upon each end of the mass facing the direction of movement of said mass.

21. The drive of claim 16 wherein the mass is mounted for movement between two further gas springs.

22. The drive of claim 20 wherein the two further gas springs are in fluid flow communication with said first gas spring.

17. a first diaphragm located in the housing adjacent to the prime mover in one volume,

a second diaphragm located in the second volume that acts against a first gas spring whereby vibrations transmitted to the housing by the prime mover are converted to pressure waves in the fluid to cause the piston to oscillate in the cylinder along its axis,

a vibration absorber mounted upon the housing adjacent the first gas spring that contains an absorber mass slidably contained therein that moves along a path of travel that is parellel to the axis of the cylinder, a spring means acting upon the absorber mass so that the resonant frequency of the absorber is matched to the natural frequency of the system.