Motorcycle rear suspension swingarm assembly

• US 6,860,353 B2
• Filed: 06/20/2002
• Issued: 03/01/2005
• Est. Priority Date: 06/20/2001
• Status: Expired due to Term

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Miyashiro, Shidehiko
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): LUM VANNUCCI, LEE SIN YEE
• Application Number:
  US10/178,311
• Publication Number:
  US 20030010557A1
• Time in Patent Office: 985 Days
• Field of Search: 180/227, 180/219, 280284-286, 280/288
• US Class Current: 180/227
• CPC Class Codes: B62K 25/283 for cycles without a pedal crank, e.g. motorcycles

Abstract

An off-road motorcycle incorporating a swingarm assembly for pivotally supporting a rear wheel relative to a main frame portion of the motorcycle. Preferably, the swingarm includes right and left arms extending rearwardly from a forward connecting portion. Right and left rear wheel mount members are secured to the right and left arms, respectively, to rotatably support the rear wheel of the motorcycle. Preferably, the arms from the swingarm assembly are formed at least partially by a hydroforming process wherein the center of the arms has a width that is greater than the width of either a forward or rearward end of the arm. In addition, the forward ends of each of the right end left arms are bent inward such that the forward portion of the swingarm assembly is narrower than the rear portion of the swingarm assembly. Desirably, the hydroforming process permits the inner wall of the arms to be vertical and substantially planar, even along the region where the arms are bent. In addition, a vibration absorbing coating is applied to the wheel support members in a manner to be interposed between an inner surface of the wheel support members and the outermost portion of a hub of the rear wheel.

Claims

1. An off-road motorcycle comprising a frame, a front suspension assembly rotatably supported by the frame and rotatably supporting a front wheel, a rear swingarm assembly pivotably supported by the frame and rotatably supporting a rear wheel, an internal combustion engine supported by the frame and being configured to drive the rear wheel, the swingarm assembly comprising at least one elongated, tubular arm extending along a side of the rear wheel in a direction substantially aligned with a vertical, central plane of the motorcycle, the swingarm assembly having a rearward end portion member mounted to the tubular arm and arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, the inner surface having a first portion and a second portion, the second portion defining a contact surface arranged to directly contact a portion of the hub assembly and being spaced from the first portion toward the hub assembly to define a thickened area of the end portion, which is thicker than a thinner area defined by the first portion.

4. The motorcycle of claim 1, additionally comprising an annular member fixed to an inner surface of the end portion, the annular member defining the second portion of the inner surface.

2. An off-road motorcycle comprising a frame, a front suspension assembly rotatably supported by the frame and rotatably supporting a front wheel, a rear swingarm assembly pivotably supported by the frame and rotatably supporting a rear wheel, an internal combustion engine supported by the frame and being configured to drive the rear wheel, the swingarm assembly comprising at least one elongated, tubular arm extending along a side of the rear wheel in a direction substantially aligned with a vertical, central plane of the motorcycle, the arm having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, the inner surface having a first portion and a second portion, the second portion defining a contact surface arranged to contact a portion of the hub assembly and being spaced from the first portion toward the hub assembly to define a thickened area of the end portion, wherein the contact surface comprises a dry lubricant material.

3. The motorcycle of claim 2, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

5. An off-road motorcycle comprising a frame, a front suspension assembly rotatably supported by the frame and rotatably supporting a front wheel, a rear swingarm assembly pivotably supported by the frame and rotatably supporting a rear wheel, an internal combustion engine supported by the frame and being configured to drive the rear wheel, the swingarm assembly comprising at least one elongated, tubular arm extending along a side of the rear wheel in a direction substantially aligned with a vertical, central plane of the motorcycle, the arm having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, the inner surface having a first portion and a second portion, the second portion defining a contact surface arranged to contact a portion of the hub assembly and being spaced from the first portion toward the hub assembly to define a thickened area of the end portion, additionally comprising an annular member fixed to an inner surface of the end portion, the annular member defining the second portion of the inner surface, wherein the contact surface comprises a dry lubricant material.

6. The motorcycle of claim 5, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

7. An off-road motorcycle comprising a frame, a front suspension assembly rotatably supported by the frame and rotatably supporting a front wheel, a rear swingarm assembly pivotably supported by the frame and rotatably supporting a rear wheel, an internal combustion engine supported by the frame and being configured to drive the rear wheel, the swingarm assembly comprising at least one elongated, tubular arm extending along a side of the rear wheel in a direction substantially aligned with a vertical, central plane of the motorcycle, the arm having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, wherein a portion of the inner surface contacting the hub comprises a lubricious layer.

8. The off-road motorcycle of claim 7, wherein the at least one arm comprises a first arm and a second arm, the first and second arms being positioned on opposing sides of the rear wheel.

9. The motorcycle of claim 7, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

10. A rear suspension swingarm assembly for an off-road motorcycle, the swingarm assembly configured to be pivotably supported by a frame of the motorcycle and rotatably supporting a rear wheel of the motorcycle, the swingarm assembly comprising a connecting portion defining a pivot axis of the swingarm assembly relative to the frame of the motorcycle, the swingarm assembly additionally comprising a first elongated, tubular arm and a second elongated, tubular arm, each of the first and second arms being fixed to the connecting portion and extending along a side of the rear wheel, first and second rearward end portion members mounted to the first and second tubular arms respectively and arranged to receive an axle, the axle being configured to support a hub of the rear wheel, each end portion member having an inner surface facing the hub, the inner surface having a first thinner portion facing the hub and a second thickened portion directly contacting the hub and extending from the first thinner portion toward the hub assembly.

13. The swingarm assembly of claim 10, additionally comprising an annular member fixed to an inner surface of the end portion, the annular member defining the thickened portion of the inner surface.

11. A rear suspension swingarm assembly for an off-road motorcycle, the swingarm assembly configured to be pivotably supported by a frame of the motorcycle and rotatably supporting a rear wheel of the motorcycle, the swingarm assembly comprising a connecting portion defining a pivot axis of the swingarm assembly relative to the frame of the motorcycle, the swingarm assembly additionally comprising a first elongated, tubular arm and a second elongated, tubular arm, each of the first and second arms being fixed to the connecting portion and extending along a side of the rear wheel, each of the arms having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, the inner surface having a thickened portion extending toward the hub assembly, wherein the thickened portion comprises a contact surface having a lubricious layer.

12. The swingarm assembly of claim 11, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

14. A rear suspension swingarm assembly for an off-road motorcycle, the swingarm assembly configured to be pivotably supported by a frame of the motorcycle and rotatably supporting a rear wheel of the motorcycle, the swingarm assembly comprising a connecting portion defining a pivot axis of the swingarm assembly relative to the frame of the motorcycle, the swingarm assembly additionally comprising a first elongated, tubular arm and a second elongated, tubular arm, each of the first and second arms being fixed to the connecting portion and extending along a side of the rear wheel, each of the arms having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, the inner surface having a thickened portion extending toward the hub assembly, additionally comprising an annular member fixed to an inner surface of the end portion, the annular member defining the thickened portion of the inner surface, wherein the contact surface comprises a vibration absorbing material.

15. The swingarm assembly of claim 14, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

16. A rear suspension swingarm assembly for an off-road motorcycle, the swingarm assembly configured to be pivotably supported by a frame of the motorcycle and rotatably supporting a rear wheel of the motorcycle, the swingarm assembly comprising a connecting portion defining a pivot axis of the swingarm assembly relative to the frame of the motorcycle, the swingarm assembly additionally comprising a first elongated, tubular arm and a second elongated, tubular arm, the first and second arms being fixed to the connecting portion and extending along a side of the rear wheel, each of the arms having a rearward end portion arranged to receive an axle, the axle being configured to support a hub assembly of the rear wheel, the end portion having an inner surface facing the hub assembly, wherein a portion of the inner surface contacting the hub comprises a vibration absorbing coating.

17. The swingarm assembly of claim 16, wherein the first and second arms are positioned on opposing sides of the rear wheel.

18. The swingarm assembly of claim 16, wherein a remainder of the swingarm assembly is coated with an aluminum anodic coating.

19. A rear suspension swingarm assembly for an off-road motorcycle, the swingarm assembly configured to be pivotably supported by a frame of the motorcycle and rotatably supporting a rear wheel of the motorcycle, the swingarm assembly comprising a connecting portion defining a pivot axis of the swingarm assembly relative to the frame of the motorcycle, the swingarm assembly additionally comprising a first elongated arm and a second elongated arm, each of the first and second arms being fixed to the connecting portion and extending along a side of the rear wheel, each of the arms having a rearward end portion with an aperture arranged to receive an axle, the axle being configured to support a hub of the rear wheel, the end portion having an inner surface facing the hub, the inner surface having a first area extending around the aperture and defining a hub contact area configured to directly contact the hub, and a second area immediately adjacent to the first area, the second area being recessed away from the hub relative to the first area such that the first area projects inwardly from the second area toward the hub.

20. The rear suspension swingarm assembly as set forth in claim 19, wherein the first area defines a thickened area of the end portion that is thicker than the second area.

21. The rear suspension swingarm assembly as set forth in claim 19, wherein the first area extends completely around a periphery of the aperture.

22. The rear suspension swingarm assembly as set forth in claim 19, wherein the first area is annular in shape.

23. The rear suspension swingarm assembly as set forth in claim 19, wherein the first area defines a first planar area lying in a first plane and the second area defines a second planar area lying in a second plane, the first plane being disposed closer to the hub than the second plane.