Limiting system for a vehicle suspension component

• US 10,030,737 B2
• Filed: 03/29/2016
• Issued: 07/24/2018
• Est. Priority Date: 03/10/2013
• Status: Active Grant

• Current Assignee: Oshkosh Defense LLC (Oshkosh Corporation)
• Original Assignee: Oshkosh Defense LLC (Oshkosh Corporation)
• Inventors: Dillman, Patrick S., Ellifson, Erik S., Rositch, Aaron J.
• Primary Examiner(s): Burch, Melody M
• Application Number:
  US15/084,375
• Publication Number:
  US 20160208883A1
• Time in Patent Office: 847 Days
• Field of Search: 188313, 188316, 188317, 18832213, 18832215, 18832216, 18832218, 267 6411, 13762512
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: F16F 15/161 characterised by the fluid damping devices, e.g. passages, orifices F16F15/162 takes precedence
• CPC Class Codes: F16F 2222/12 Fluid damping
• CPC Class Codes: F16F 9/16 involving only straight-line movement of the effective parts wing closers or openers with liquid piston brakes E05F3/04
• CPC Class Codes: F16F 9/368 Sealings in pistons
• CPC Class Codes: F16F 9/49 Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping fluid-actuated displacement devices with means for accelerating or decelerating the stroke F15B15/22
• CPC Class Codes: F16F 9/512 Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044

Abstract

The damper assembly includes a tubular member, a rod, a primary piston, a secondary piston, and a resilient member. The tubular member includes a sidewall and a cap positioned at an end of the sidewall. The sidewall and the cap define an inner volume. The rod extends within the inner volume. The primary piston is positioned within the inner volume and coupled to the rod. The primary piston defines a first contact surface. The secondary piston includes a body member having a second contact surface, an opposing second surface, and an inner cylindrical face defining a central aperture that receives the rod. The secondary piston defines a channel extending from the inner cylindrical face to an outer periphery of the body member. The first contact surface and the channel are configured to cooperatively define a flow conduit upon engagement between the primary piston and the secondary piston.

Claims

1. A damper assembly, comprising:

a tubular member including a sidewall and a cap positioned at an end of the sidewall, the sidewall and the cap defining an inner volume, wherein the sidewall includes a shoulder separating the tubular member into a first portion and a second portion;

a rod extending within the inner volume;

a primary piston positioned within the inner volume and coupled to the rod, the primary piston defining a first contact surface;

a secondary piston including a body member having a second contact surface, an opposing second surface, and an inner cylindrical face defining a central aperture that receives the rod, the secondary piston defining a channel extending from the inner cylindrical face to an outer periphery of the body member, wherein the primary piston and the secondary piston separate the inner volume into a first working chamber, a second working chamber, and a recoil chamber;

a resilient member disposed between the secondary piston and the cap and thereby positioned to bias the secondary piston into engagement with the shoulder; and

a seal disposed between the outer periphery of the secondary piston and the sidewall of the tubular member;

wherein the first contact surface and the channel are configured to cooperatively define a flow conduit upon engagement between the primary piston and the secondary piston;

wherein the second contact surface is configured to engage the first contact surface such that an open flow path is formed from the recoil chamber through the central aperture and the flow conduit upon engagement between the primary piston and the secondary piston.

2. The damper assembly of claim 1, wherein the recoil chamber is defined between the opposing second surface of the secondary piston and the cap.

3. The damper assembly of claim 1, wherein the primary piston, the first portion, and the second portion have circular cross-sectional shapes.

4. The damper assembly of claim 3, wherein the first portion has a first diameter and the second portion has a second diameter, wherein the first diameter is greater than the second diameter, and wherein the transition between the first portion and the second portion defines the shoulder.

5. The damper assembly of claim 4, wherein the diameter of the primary piston is less than the second diameter such that the primary piston is extendable along the length of the tubular member.

10. The damper assembly of claim 1, wherein the primary piston is moveable within the tubular member between a first location, an intermediate location, and an end of stroke, and wherein the primary piston is configured to maintain engagement with the secondary piston between the intermediate location and the end of stroke.

11. The damper assembly of claim 10, wherein the damper assembly provides a base level of damping as the primary piston moves between the first location and the intermediate location and an increased level of damping as the primary piston moves between the intermediate location and the end of stroke.

12. The damper assembly of claim 1, wherein the primary piston is coupled to an end of the rod.

6. A damper assembly, comprising:

a housing having an end cap and defining an inner volume including a first portion and a second portion, wherein the transition between the first portion and the second portion defines a shoulder;

a primary piston positioned within the housing; and

a limiter positioned between the primary piston and the end cap, the limiter comprising;

a damper piston including a body member having a contact surface, an opposing second surface, and an inner cylindrical face that defines an aperture through a central portion of the body member, the primary piston and the damper piston separating the inner volume into a first working chamber, a second working chamber, and a recoil chamber;

a resilient member disposed within the recoil chamber, between the opposing second surface of the damper piston and the end cap, the resilient member thereby positioned to bias the damper piston into engagement with the shoulder; and

a ring coupling the damper piston to the housing, wherein the ring comprises a seal; and

a rod coupled to the primary piston and extending through the aperture defined by the damper piston;

wherein the damper piston defines a channel extending laterally outward from the inner cylindrical face across the contact surface to an outer periphery of the body member, wherein the primary piston and the channel are configured to cooperatively define a first flow conduit upon engagement between the primary piston and the damper piston; and

wherein an outer surface of the rod and the inner cylindrical face of the damper piston define a second flow conduit, and wherein the first flow conduit and the second flow conduit cooperate to define an open flow path from the recoil chamber.

7. The damper assembly of claim 6, wherein the primary piston is moveable within the housing between a first location, an intermediate location, and an end of stroke, and wherein the primary piston is configured to maintain engagement with the limiter between the intermediate location and the end of stroke.

8. The damper assembly of claim 7, wherein the damper assembly provides a base level of damping as the primary piston moves between the first location and the intermediate location and an increased level of damping as the primary piston moves between the intermediate location and the end of stroke.

9. The damper assembly of claim 6, wherein the recoil chamber is defined between the opposing second surface of the damper piston and the end cap.

13. The damper assembly of claim 6, wherein the primary piston, the first portion, and the second portion have circular cross-sectional shapes.

14. The damper assembly of claim 13, wherein the first portion has a first diameter and the second portion has a second diameter, wherein the first diameter is greater than the second diameter, and wherein the transition between the first portion and the second portion defines the shoulder.

15. The damper assembly of claim 14, wherein the diameter of the primary piston is less than the second diameter such that the primary piston is extendable along the length of the housing.

16. The damper assembly of claim 6, wherein an end of the rod is coupled to the primary piston.

17. The damper assembly of claim 6, wherein the seal is a polymeric seal.