Suspension device

1. A suspension device having a suspension device main body interposed between a vehicle body and a vehicle wheel, and a stroke locking mechanism capable of locking expansion/contraction of the suspension device main body, the stroke locking mechanism comprising:

a tube member coupled to one of the vehicle body and the vehicle wheel;

a partition wall body fixed inside the tube member to divide an interior of the tube member into

a first chamber; and

a second chamber including a reservoir portion;

a flow passage that connects the first chamber to the second chamber;

a valve that is configured to cut off the flow passage during stroke locking;

a shaft member coupled to another of the vehicle body and the vehicle wheel and inserted into the first chamber to be capable of advancing and retreating; and

a piston held on a tip end of the shaft member to divide the first chamber into two chambers including a piston-side chamber and a shaft member-side chamber,

wherein the first chamber is filled with working fluid, and working fluid is stored in the reservoir portion of the second chamber,

wherein the flow passage includes

a first flow passage that connects the piston-side chamber to the reservoir portion of the second chamber; and

a second flow passage that connects the shaft member-side chamber to the reservoir portion of the second chamber, and

wherein when the stroke locking mechanism permits the expansion/contraction of the suspension device main body and the shaft member advances into the tube member, working fluid having a volume corresponding to a movement of the piston relative to the tube member flows from the piston side chamber into the reservoir portion through the first flow passage, and working fluid in the reservoir portion flows into the shaft member side chamber through the second flow passage,

when the stroke locking mechanism permits the expansion/contraction of the suspension device main body and the shaft member retreats from the tube member, working fluid having a volume corresponding to a movement of the piston relative to the tube member flows from the shaft member side chamber into the reservoir portion through the second flow passage, and working fluid in the reservoir portion flows into the piston side chamber through the first flow passage, and

when the stroke locking mechanism restricts the expansion/contraction of the suspension device main body, the valve cuts off the first flow passage and the second flow passage.

2. The suspension device as defined in claim 1 , wherein the stroke locking mechanism further comprises:

a cylinder that stands upright inside the tube member such that the piston slides against an inner peripheral surface thereof; and

a cylinder exterior passage formed between the cylinder and the tube member, the two chambers being formed inside the cylinder,

the first flow passage being constituted by an inner peripheral side connecting passage penetrating an axial center portion of the partition wall body, and

the second flow passage being constituted by an outer peripheral side connecting passage penetrating an outer peripheral portion of the partition wall body, the cylinder exterior passage, and a hole formed in the cylinder to connect the shaft member-side chamber to the cylinder exterior passage.

3. The suspension device as defined in claim 1 , wherein the tube member is coupled to the vehicle body, the shaft member is coupled to the vehicle wheel, and the stroke locking mechanism further comprises

an annular cap member blocking a vehicle body side opening of the tube member; and

an adjuster screwed to an inner periphery of the cap member, and the valve being held by a tip end of the adjuster.

4. The suspension device as defined in claim 3 , wherein the stroke locking mechanism further comprises:

a cylinder that stands upright inside the tube member such that the piston slides against an inner peripheral surface thereof; and

an annular rod guide that blocks a vehicle wheel side opening of the tube member, the shaft member penetrating the rod guide to be free to move in an axial direction, the cap member and the rod guide being screwed to inner peripheries of respective end portions of the tube member, and the cylinder and the partition wall body being sandwiched between the cap member and the rod guide.

5. The suspension device as defined in claim 1 , wherein

the valve always cuts off the second flow passage when the valve cuts off the first flow passage, and

the valve always cuts off the first flow passage when the valve cuts off the second flow passage.

6. The suspension device as defined in claim 1 , wherein

the valve always opens the second flow passage when the valve opens the first flow passage, and

the valve always opens the first flow passage when the valve opens the second flow passage.

7. The suspension device as defined in claim 1 , wherein when the stroke locking mechanism permits the expansion/contraction of the suspension device main body, and the piston moves relative to the tube member,

working fluid is communicated from the first flow passage to the second flow passage, or

working fluid is communicated from the second flow passage to the first flow passage.