Damper baffle tube with elastomeric skirt
View Patent ↗A shock absorber with a pressure tube, a reserve tube, and a piston slidably disposed within the pressure tube to define first and second working chambers. A reservoir chamber is positioned between the pressure tube and the reserve tube. A damper baffle tube, positioned in the reservoir chamber, defines a baffle tube chamber between the pressure tube and the damper baffle tube. One or more electromechanical valves are positioned in fluid communication with the first working chamber and the baffle tube chamber. The damper baffle tube includes a compliant portion that has a sealing surface configured to move into and out of contact with the pressure tube in response to fluctuations in fluid pressure in the baffle tube chamber so as to form a check valve that holds a constrained volume of hydraulic fluid in the baffle tube chamber.
1. A shock absorber comprising:
a pressure tube extending between a first pressure tube end and a second pressure tube end;
a piston attached to a piston rod, the piston slidably disposed within the pressure tube to define a first working chamber between the piston and the first pressure tube end and a second working chamber between the piston and the second pressure tube end, the piston including at least one fluid passage that connects the first working chamber with the second working chamber;
a reserve tube disposed around the pressure tube that defines a reservoir chamber positioned between the pressure tube and the reserve tube;
a damper baffle tube positioned radially outward from the pressure tube and defining a baffle tube chamber between the pressure tube and the damper baffle tube;
at least one electromechanical valve positioned in fluid communication with the first working chamber and the baffle tube chamber,
wherein the damper baffle tube includes a compliant portion surrounding the pressure tube with a sealing surface that is configured to move into and out of contact with the pressure tube in response to fluctuations in fluid pressure in the baffle tube chamber such that the compliant portion of the damper baffle tube forms a check valve that retains hydraulic fluid in the baffle tube chamber, and
a rod guide attached to the first pressure tube end and supporting the piston rod, wherein the at least one electromechanical valve is positioned in the rod guide, the damper baffle tube including a first baffle tube end that is sealingly attached to the rod guide and a second baffle tube end that is formed by the compliant portion of the damper baffle tube, wherein the first baffle tube end is spaced radially inward of the reserve tube defining a clearance volume therebetween that is disposed in uninterrupted fluid communication with the reservoir chamber, the rod guide including at least one bleed passage extending between the clearance volume and at least one of the first working chamber and the baffle tube chamber.
2. The shock absorber of claim 1 , wherein the first baffle tube end includes a metal sleeve that is press-fit onto the rod guide and wherein the compliant portion of the damper baffle tube is made of an overmolded elastomeric material.
3. The shock absorber of claim 1 , wherein the first baffle tube end is made of an elastomeric material and is squeezed between the rod guide and the reserve tube to create an integrated static seal.
4. The shock absorber of claim 1 , wherein the at least one electromechanical valve includes an inlet disposed in fluid communication with the first working chamber and an outlet disposed in fluid communication with the baffle tube chamber.
5. The shock absorber of claim 4 , wherein the compliant portion of the damper baffle tube is made of an elastomeric material and has a compliant portion stiffness such that the damper baffle tube holds a constrained volume of hydraulic fluid at the outlet of the at least one electromechanical valve.
6. The shock absorber of claim 5 , wherein the compliant portion stiffness provides a check valve opening pressure where the sealing surface moves away from the pressure tube and permits the hydraulic fluid in the baffle tube chamber to flow into the reservoir chamber.
7. The shock absorber of claim 6 , further comprising:
a piston valve assembly that restricts fluid flow through the at least one fluid passage in the piston, the piston valve assembly having a piston valve opening pressure; and
a base valve assembly positioned at the second pressure tube end that restricts fluid flow between the second working chamber and the reservoir chamber, the base valve assembly having a base valve opening pressure,
wherein the check valve opening pressure is less than the piston valve opening pressure and the base valve opening pressure.
8. The shock absorber of claim 1 , wherein the compliant portion of the damper baffle tube has an inwardly tapering shape.
9. The shock absorber of claim 1 , wherein the sealing surface of the damper baffle tube is defined by an inwardly directed annular lip.
10. The shock absorber of claim 1 , wherein the compliant portion of the damper baffle tube is made of natural butyl rubber or fluorosilicone.
11. The shock absorber of claim 1 , wherein the damper baffle tube has a one-piece structure and is made of an elastomeric material.