Elastomer damper

• US 6,247,687 B1
• Filed: 03/29/1999
• Issued: 06/19/2001
• Est. Priority Date: 03/29/1999
• Status: Expired due to Term

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Miller, Scott K., Jensen, William S.
• Primary Examiner(s): Butler, Douglas C.
• Assistant Examiner(s): SICONOLFI, ROBERT
• Application Number:
  US09/277,886
• Time in Patent Office: 813 Days
• Field of Search: 267/196, 267/200, 267/201, 267/202, 267/203, 188/381, 188/271, 188/322.16, 188/322.17, 188/322.18, 188/129
• US Class Current: 267/200
• CPC Class Codes: B64C 25/64 using rubber or like elements
• CPC Class Codes: F16F 7/09 in dampers of the cylinder-and-piston type
• CPC Class Codes: F16F 9/3242 of cylinder ends, e.g. caps

Abstract

An elastomer damper (20) for damping movement between two relatively moveable members, such as shimmy motion between components in an aircraft landing gear assembly (10). The damper (20) includes a housing (24) having an internal cavity (36) with a cylindrical interior surface (34) and an opening (41), and a member assembly (28) moveable relative to the housing (24) having an elongated shaft (30) received through the opening (41) with a piston head assembly (32) mounted thereon. The piston head assembly (32) has a annular support element (46) received over the shaft (30) with a sleeve-like elastomer member (48) received over it. The elastomer member (48) engages the interior surface (34) in an interference fit relationship thereby radially precompressing the elastomer element (48) in the range of between about 5% and 15%. Low friction washers (50a, 50b) are preferably positioned adjacent to the ends of the elastomer ember (48) and the support member (46). Rigid washers (54a, 54b) may be provided to abut and support the low friction washers (50a, 50b). The elastomer member (48) preferably has grooves (51) forming a plurality of ribs (53) that are preferably axially oriented.

Claims

1. An elastomer damper, comprising:

(a) a housing including an internal cavity having a cylindrical interior surface of a first diameter, a first closed end, and a second end including an opening therein, and

(b) a member assembly moveable relative to the housing, the member assembly including;

an elongated shaft received through the opening, and

a piston head assembly mounted to the shaft, the piston head assembly including;

a support element received over the shaft, and

a unitary elastomer sleeve received over the support element, the elastomer sleeve having a thickness, a first end, a second end, a plurality of grooves formed thereon, the grooves extending between the first and second ends and traversing the sleeve radially a majority of the way through the sleeve thickness, the sleeve further comprising a plurality of radially compressible ribs, each rib being defined by a pair of adjacent grooves, the sleeve further comprising an outer diameter larger than the first diameter such that the elastomer sleeve engages the cylindrical interior surface in an interference fit relationship radially precompressing the elastomer sleeve ribs, whereby the elastomer sleeve is axially slidable thereagainst to generate a damping force.

2. The elastomer damper of claim 1 wherein the housing further comprises an end cap including the opening.

3. The elastomer damper of claim 2 wherein the elongated shaft is received through the opening in the end cap.

4. The elastomer damper of claim 2 wherein the end cap is retained by a retaining clip.

5. The elastomer damper of claim 1 wherein the second end includes a bearing.

6. The elastomer damper of claim 1 wherein the second end includes a wiper seal.

7. The elastomer damper of claim 1 wherein the housing further comprises an end cap having a bearing and wiper seal mounted therein which engage the shaft.

8. The elastomer damper of claim 1 wherein at least one low friction washer is received adjacent to an end of the sleeve.

9. The elastomer damper of claim 8 wherein the at least one low friction washer comprises a first low friction washer abutting at a first end of the sleeve and a second low friction washer abutting a second end of the sleeve.

10. The elastomer damper of claim 8 wherein the piston head assembly further comprises at least one rigid washer abutting the at least one low friction washer.

11. The elastomer damper of claim 1 wherein at least one low friction washer engages an axial end of the support member.

12. The elastomer damper of claim 1 wherein the piston head assembly is held in place between a step formed on the shaft and a nut threaded onto a threaded portion of the shaft.

13. The elastomer damper of claim 1 wherein the grooves are substantially axially oriented.

14. The elastomer damper of claim 1 wherein a length of the elastomer sleeve in a free state is slightly larger that a length of the support element.

15. The elastomer damper of claim 1 wherein the elastomer sleeve is precompressed radially in the range of between about 5% and about 15%.

16. The elastomer damper of claim 15 wherein the elastomer sleeve is precompressed by about 8%.

17. The elastomer damper of claim 1 wherein the elastomer sleeve is precompressed by an appropriate amount such that the precompression is not completely relieved at any temperature within a design operating temperature range of the damper.

18. The elastomer damper of claim 1 wherein the support element comprises an annulus.

19. The elastomer damper of claim 1 wherein the elastomer sleeve includes an inner diameter which in a free state is slightly smaller than an outer diameter of the support element.

20. The elastomer damper of claim 1 wherein the ribs thereon exhibit a shape factor of between about 0.3 to about 1.2.

21. The elastomer damper of claim 1 wherein the ribs formed on the elastomer sleeve exhibit a width-to-height ratio of about 0.6 to about 2.4.

22. The elastomer damper of claim 1 wherein the elastomer sleeve is lubricated with a grease.

23. The elastomer damper of claim 1 wherein the grease comprises a silicone grease including a filler.

24. A landing gear assembly including the elastomer damper of claim 1 wherein the landing gear assembly includes first and second relatively moveable components and wherein the housing interconnects to the first component and the shaft interconnects to the second component such that the damper may provide damping therebetween.

25. An elastomer damper, comprising:

(a) a housing including an internal cavity having a cylindrical interior surface of a first diameter, a first closed end and a second end having an end cap including an opening having a bearing mounted therein,

(b) a member assembly moveable relative to the housing, the member assembly including;

an elongated shaft received through the opening and slidably engagable with the bearing, and

a piston head assembly mounted to the shaft, the piston head assembly including;

an annular support element received over the shaft, and

an annular unitary elastomer sleeve, sleeve having a radial thickness, a first end, a second end, a plurality of grooves formed thereon, the grooves extending between the first and second ends and traversing the sleeve radially a majority of the way through the sleeve thickness, the sleeve further comprising, a plurality of axially extending and radially compressible ribs each rib being defined by a pair of adjacent grooves, the elastomer sleeve being mounted to the shaft and having an outer surface received over the shaft, the elastomer sleeve having an outer diameter larger than the first diameter such that the annular elastomer sleeve engages the cylindrical interior surface in an interference fit relationship thereby radially precompressing the annular elastomer sleeve by between about 5% and about 15% of a free radial height of the annular elastomer sleeve, the annular elastomer sleeve axially slidable against the cylindrical interior surface to generate a damping force.

26. An elastomer damper, comprising:

(a) a housing including an elongated internal cavity having a cylindrical interior surface of a first diameter, a first closed end and a second end including an end cap having an opening formed therein,

(b) a member assembly moveable relative to the housing, the member assembly including;

an elongated shaft slidably received through the opening, and

a piston head assembly mounted to an end of the shaft, the piston head assembly including;

an annular support element including a cylindrical outer surface received over the shaft;

an annular unitary elastomer sleeve having a radial thickness, a first end, a second end, a plurality of grooves formed thereon, the grooves extending between the first and second ends and traversing the sleeve radially a majority of the way through the sleeve thickness, the sleeve further comprising, a plurality of axially extending and radially compressible ribs each rib being defined by a pair of adjacent grooves, the elastomer sleeve being mounted to the shaft and having an outer surface received over the shaft, the sleeve being received over the cylindrical outer surface of the annular support element, the elastomer sleeve having an outer diameter larger than the first diameter such that the annular elastomer sleeve engages the cylindrical interior surface in an interference fit relationship thereby radially precompressing the ribs by about between 5% and 15% of a free radial height of the annular elastomer sleeve; and

low friction washers received adjacent to both ends of the sleeve and extending toward the cylindrical interior surface and stopping in relatively close proximity thereof wherein the annular elastomer sleeve axially slidable against the cylindrical interior surface to generate a damping force.

27. An elastomer damper, comprising:

(a) a housing including a cavity having an interior surface of a first diameter,

(b) a member assembly moveable relative to the housing, the member assembly including;

a shaft, and

a unitary elastomer member including a radial thickness, a first end, a second end, a plurality of grooves formed thereon, the grooves extending between the first and second ends and traversing the sleeve radially a majority of the way through the sleeve thickness, the sleeve further comprising, the elastomer member further comprising a plurality of axially extending and radially compressible ribs each rib being defined by a pair of adjacent grooves, the elastomer member being mounted to the shaft and having an outer diameter larger than the first diameter such that the elastomer member engages the cylindrical interior surface in an interference fit relationship whereby the ribs are radially compressed, and wherein the axial ribs include a width-to-height ratio of between about 0.6 to 2.4, the elastomer member being axially slidable against the cylindrical interior surface to generate a damping force.