SPOKE FOR A TIRE WITH OPTIMIZED THICKNESS FOR IMPROVED DURABILITY

• US 20150174953A1
• Filed: 04/03/2013
• Published: 06/25/2015
• Est. Priority Date: 04/05/2012
• Status: Active Grant

• Current Assignee: Compagnie générale des établissements Michelin
• Original Assignee: Compagnie générale des établissements Michelin, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Cron, Steven M, Rhyne, Timothy Brett
• Granted Patent: US 9,290,045 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60B 2900/30 Increase in
• CPC Class Codes: B60B 2900/321 Lifetime
• CPC Class Codes: B60B 2900/325 Reliability
• CPC Class Codes: B60B 9/26 comprising resilient spokes
• CPC Class Codes: B60C 7/146 extending substantially radially, e.g. like spokes
• CPC Class Codes: B60C 7/18 disposed radially relative to wheel axis

Abstract

The present invention provides spoke geometry for a non-pneumatic tire that is less prone to fatigue when used. In particular, the spoke geometry is provided with an optimized thickness profile over the length of the spoke. This optimization results in a reduction in the peak strain energy density levels in the spoke, thereby reducing the likelihood of crack initiation and propagation which in turn enhances the durability of the spoke and tire.

Claims

1. A tire that defines radial and transverse directions and comprises a tread and a spoke having body geometry including a thickness that varies along the length of the spoke along the general radial direction that starts at one value, that gradually reduces to a second value, that then gradually increases to a third value, that then reduces to a fourth value and that then increases again to a fifth value wherein the length of said spoke follows a path and said path is offset from perfectly straight path from a first end of said spoke a second end of said spoke.

2. A tire according to claim 1 wherein the first, third and fifth values of the thickness of the spoke are substantially the same.

3. A tire according to claim 2 wherein the second and fourth values of the thickness of the spoke are substantially the same.

4. A tire according to claim 3 wherein the second and fourth values of the thickness of the spoke are approximately 60% the value of the first, third and fifth values.

5. A tire according to claim 4 wherein the tire is a 205/55N16 sized tire, the first, third and fifth values of the thickness of the spoke is approximately 3.4 mm while the second and fourth values of the thickness of the spoke is approximately 2.0 mm and the tire comprises a plurality of similarly configured spokes.

6. A tire according to claim 5 wherein the radial height of the spoke is approximately 76 mm.

7. A tire according to claim 6 wherein the spoke has an offset or deviation of its path between the two ends of the spoke wherein the offset is 25% or less of the radial height of the spoke, and is preferably around 15% of the radial height of the spoke.

8. A tire according to claim 7 wherein the spoke is configured to elastically deform when subjected to a deflection of 15 mm toward the center of the tire along its radial direction.

9. A tire that defines radial and transverse directions and comprises a tread and a spoke having body geometry including a thickness that varies along the length of the spoke along the general radial direction that starts at one value, that gradually reduces to a second value, that then gradually increases to a third value, that then reduces to a fourth value and that then increases again to a fifth value wherein the thickness of the spoke increases and decreases twice along the length of the spoke and the spoke comprises four zones or regions and has a centerline along the length of the spoke and wherein said centerline has two inflection points and a midpoint found between said inflection points along the centerline.

10. A tire according to claim 9 wherein the first value of the thickness of the spoke may be found at one end of the spoke and the fifth value of the thickness of the spoke may be found at the other end of the spoke and wherein the first zone is a transition region between said first end and a first inflection point where the thickness reduces to the second value, the second zone is a transition region between the first inflection point and the midpoint where the thickness increases to a third value, the third zone is a transition region between the midpoint and the second inflection point where the thickness increases to the fourth value, and the fourth zone is a transition region between the second inflection point and the other end of the spoke where the thickness increases to the fifth value.

11. A tire according to claim 10 wherein the second and fourth values of the thickness is approximately 60% of the value of the first, third and fifth values.

12. A tire according to claim 11 wherein the tire is a 205/55N16 sized tire and the first, third and fifth values of the spoke is approximately 3.4 mm and the second and fourth values of the thickness of the spoke is approximately 2.0 mm and the tire comprises a plurality of similarly configured spokes.

13. A tire according to claim 12 wherein the spoke has a radial height of approximately 76 mm.

14. A tire according to claim 13 wherein the spoke has an offset or deviation of the spoke from a perfectly straight path along the radial direction and said offset is 25% or less of the radial height of the spoke, and is preferably around 15% of the radial height of the spoke.

15. A tire according to claim 14 wherein the spoke is configured to elastically deform when subjected to a deflection of 15 mm toward the center of the tire along the radial direction of the tire.

16. A tire according to claim 9 wherein the centerline is constructed from a series of analytical curves such as lines and arcs and the spoke further comprises boundary curves that are also constructed from analytical curves such as lines and arcs.