Snowmobile suspension

1. A snowmobile comprising:

a chassis including a tunnel, the tunnel having a longitudinal axis;

an engine disposed on the chassis;

an endless drive track disposed below the tunnel and operatively connected to the engine for propulsion of the snowmobile;

two skis disposed on the chassis, each via a front suspension;

a straddle seat disposed on the tunnel above the endless drive track, the straddle seat being disposed rearward of the engine; and

a rear suspension assembly supporting and tensioning the endless drive track, the rear suspension assembly including:

a rail for engagement with the endless drive track;

a first suspension arm having an upper end pivotally connected to the tunnel and a lower end pivotally connected to the rail, the first suspension arm extending forwardly and upwardly from the rail;

a second suspension arm disposed rearward of the first suspension arm, the second suspension arm having an upper end pivotally connected to the tunnel and a lower end pivotally connected to the rail, the second suspension arm extending forwardly and upwardly from the rail;

a bracket arm having a first end and a second end, the first end of the bracket arm being fixedly connected to the first suspension arm between the upper end and the lower end of the first suspension arm;

a link having a first end and a second end, the first end of the link being pivotally connected to the second end of the bracket arm above the first suspension arm at a link pivot axis;

a first shock absorber having an upper end and a lower end, the upper end of the first shock absorber being pivotally connected to the first suspension arm, the lower end of the first shock absorber being pivotally connected to the rail, and the lower end of the first shock absorber being disposed forwardly of the lower end of the first suspension arm;

a second shock absorber having an upper end and a lower end, the lower end of the second shock absorber being pivotally connected to the second end of the link about a first pivot axis, the first pivot axis being perpendicular to a longitudinal axis of the chassis, the first pivot axis being located between the upper and lower ends of the first suspension arm, the first pivot axis being disposed such that the first suspension arm is disposed between the first pivot axis and the link pivot axis, the upper end of the second shock absorber being pivotally connected to the second suspension arm; and

a tie rod having a lower end and an upper end, the lower end of the tie rod being pivotally connected to the link, and the upper end of the tie rod being pivotally connected to the second suspension arm.

2. The snowmobile of claim 1 , wherein the tie rod is pivotally connected to the second end of the link about the first pivot axis.

3. The snowmobile of claim 2 , wherein the tie rod and the link form an assembly through which a pivot movement of the rear suspension arm relative to the rail forces the bracket arm to act on the first suspension arm, thereby moving the first suspension arm.

4. The snowmobile of claim 2 , wherein the second end of the bracket arm extends rearwardly from the first end of the bracket arm.

5. The snowmobile of claim 2 , wherein the second end of the bracket arm extends downwardly from the first end of the bracket arm.

6. The snowmobile of claim 2 , wherein the first end of the link is pivotally connected to the second end of the bracket arm about the link pivot axis, the link pivot axis being perpendicular to the longitudinal axis of the tunnel, and the link pivot axis is upward of the first pivot axis.

7. The snowmobile of claim 6 , wherein the first end of the bracket arm is fixedly connected to the first suspension arm at a point disposed upwardly of the link pivot axis.

8. The snowmobile of claim 6 , wherein the upper end of the first suspension arm is adapted for pivotally connecting to the chassis about a second pivot axis, the upper end of the first shock absorber is pivotally connected to the first suspension arm about a third pivot axis, the third pivot axis being perpendicular to the longitudinal axis of the tunnel, and the lower end of the first suspension arm is pivotally connected to the rail about a fourth pivot axis, the fourth pivot axis being perpendicular to the longitudinal axis of the tunnel; and

wherein, when the snowmobile is at rest with no load applied thereon, a distance between the link pivot axis and the fourth pivot axis is at least a third of a distance between the second pivot axis and the fourth pivot axis.

9. The snowmobile of claim 2 , wherein the upper end of the first suspension arm is pivotally connected to the tunnel about a second pivot axis, the second pivot axis being perpendicular to the longitudinal axis of the chassis; and

wherein when the snowmobile experiences deceleration an upward reaction force is created on the second pivot axis.

10. The snowmobile of claim 2 , wherein the upper end of the first suspension arm is pivotally connected to the tunnel about a second pivot axis, the second pivot axis being perpendicular to the longitudinal axis of the chassis, and

when the snowmobile experiences acceleration, a downward reaction force is created on the second pivot axis.

11. The snowmobile of claim 2 , wherein the upper end of the second suspension arm is pivotally connected to the tunnel via a fixed connection to a link, the link being pivotally connected to the tunnel.