Suspension device for vehicle

1. A double wishbone suspension device for a vehicle, comprising:

a knuckle supporting a wheel;

an upper arm vertically rotatably connected to a vehicle body and pivotally supporting an upper portion of the knuckle;

a lower arm provided below the upper arm and vertically rotatably connected to the vehicle body; and

a coupling rod coupling the upper arm and the lower arm, wherein

said coupling rod is configured to slant in a vehicle longitudinal direction and be rotatably connected to the upper arm and the lower arm, respectively,

said upper arm is provided with a coupling-rod connection portion where said coupling rod is connected, said coupling-rod connection portion of the upper arm is configured to project substantially horizontally from the upper arm,

said lower arm is provided with a coupling-rod connection portion where said coupling rod is connected, said coupling-rod connection portion of the lower arm is configured to project substantially horizontally from the lower arm, and

said coupling rod is configured substantially in a linear-bar shape, one end portion of which is bent toward the upper arm and the other end portion of which is bent toward the lower arm.

2. The suspension device for the vehicle of claim 1 , wherein said coupling rod is connected to said upper arm and said lower arm, respectively, via a ball joint, a pillow ball, or a rubber bush.

3. The suspension device for the vehicle of claim 1 , wherein said coupling rod is configured to couple said upper arm and said lower arm in a slant state where a forward side, in a vehicle longitudinal direction, thereof is located at a higher level than a rearward side, in the vehicle longitudinal direction, thereof.

4. The suspension device for the vehicle of claim 3 , wherein said upper arm comprises a forward-side arm portion and a rearward-side arm portion, and a forward end portion of said coupling rod is connected to a forward side of said forward-side arm portion of the upper arm.

5. The suspension device for the vehicle of claim 3 , wherein said lower arm comprises a forward-side arm portion and a rearward-side arm portion, and a rearward end portion of said coupling rod is connected to a rearward side of said rearward-side arm portion of the lower arm.

6. The suspension device for the vehicle of claim 1 , wherein said coupling rod is configured to couple said upper arm and said lower arm in a slant state where a forward side, in a vehicle longitudinal direction, thereof is located at a lower level than a rearward side, in the vehicle longitudinal direction, thereof.

7. The suspension device for the vehicle of claim 6 , wherein said upper arm comprises a forward-side arm portion and a rearward-side arm portion, and a rearward end portion of said coupling rod is connected to a rearward side of said rearward-side arm portion of the upper arm.

8. The suspension device for the vehicle of claim 6 , wherein said lower arm comprises a forward-side arm portion and a rearward-side arm portion, and a forward end portion of said coupling rod is connected to a forward side of said forward-side arm portion of the lower arm.

9. The suspension device for the vehicle of claim 1 , wherein said knuckle is provided with a steering-rod connection portion where a steering rod for rotating the knuckle in a vehicle lateral direction is connected, and a coupling-rod connection portion of said lower arm where said coupling rod is connected is arranged on an opposite side, in a vehicle longitudinal direction, to said steering-rod connection portion relative to a center, in the vehicle longitudinal direction, of the knuckle.

10. The suspension device for the vehicle of claim 1 , wherein said lower arm is provided with a stabilizer connection portion where a stabilizer is connected, and a coupling-rod connection portion of said lower arm where said coupling rod is connected is arranged on an opposite side, in the vehicle longitudinal direction, to said stabilizer connection portion of the lower arm.

11. The suspension device for the vehicle of claim 1 , wherein said coupling rod is connected to respective portions of said upper arm and said lower arm which are positioned more closely to a vehicle-body side than a knuckle side, respectively.

12. A double wishbone suspension device for a vehicle, comprising:

a knuckle supporting a wheel;

an upper arm vertically rotatably connected to a vehicle body and pivotally supporting an upper portion of the knuckle;

a lower arm provided below the upper arm and vertically rotatably connected to the vehicle body; and

a coupling rod coupling the upper arm and the lower arm, wherein

said coupling rod is configured to slant in a vehicle longitudinal direction and be rotatably connected to the upper arm and the lower arm, respectively,

said coupling rod is connected to respective portions of said upper arm and said lower arm which are positioned more closely to a vehicle-body side than a knuckle side, respectively,

said upper arm and said lower arm are each provided with a forward vehicle-body connection part and a rearward vehicle-body connection part, said forward vehicle-body connection parts and said rearward vehicle-body connection parts each being provided with a rubber bush, and

said forward vehicle-body connection parts and said rearward vehicle-body connection parts are spaced apart from each other in the vehicle longitudinal direction and are rotatable in a vertical direction, an axial line of each said vehicle-body connection part being configured to extend coaxially in the vehicle longitudinal direction.