DAMPING FORCE VARIABLE VALVE OF A SHOCK ABSORBER
Provided is a damping force variable valve of a shock absorber. The damping force variable valve of the shock absorber includes: a retainer formed with an inflow passage into which a working fluid is introduced from the shock absorber; a valve body disposed behind the retainer; an elastic member pressurizing the valve body in a direction of stopping the inflow passage, behind the valve body; a spool guide formed with a back pressure control passage inducing some of the working fluid in front of the valve body into a back pressure chamber behind the valve body; and a spool moving forward and backward according a change in current of a solenoid to control an opening of the back pressure control passage, wherein the valve body moves backward from a position where the inflow passage stops to form a discharge passage between the valve body and the retainer, and the size of the discharge passage varies by the pressure of the working fluid to control the discharge extent of the working fluid. By this configuration, the valve body pressurized by the elastic member vertically moves according to the pressure and back pressure of the working fluid to open the discharge passage of the working fluid, such that the damping force of the damping force variable valve may be easily varied according to the pressure of the working fluid, thereby making it possible to obtain the desired damping force characteristics of the damping force variable valve.
1 . A damping force variable valve of a shock absorber, comprising:
a retainer formed with an inflow passage into which a working fluid is introduced from the shock absorber;
a valve body disposed behind the retainer;
an elastic member pressurizing the valve body in a direction of stopping the inflow passage, behind the valve body;
a spool guide formed with a back pressure control passage inducing some of the working fluid in front of the valve body into a back pressure chamber behind the valve body; and
a spool moving forward and backward according a change in current of a solenoid to control an opening of the back pressure control passage,
wherein the valve body moves backward from a position where the inflow passage stops to form a discharge passage between the valve body and the retainer, and
the size of the discharge passage varies by the pressure of the working fluid to control the discharge extent of the working fluid.
2 . The damping force variable valve of a shock absorber of claim 1 , further comprising a retainer disk disposed between the retainer and the valve body, wherein the retainer disk has a shape permitting the flow of the working fluid in the back pressure control passage.
3 . The damping force variable valve of a shock absorber of claim 2 , wherein the surface of the retainer is formed with a slit and the slit is formed inwardly toward the inner circumferential portion of the retainer disk to communicate with the back pressure control passage.
4 . The damping force variable valve of a shock absorber of claim 1 , further comprising an inner ring member disposed between the valve body and the elastic member to partition the inner side of the back pressure chamber.
5 . The damping force variable valve of a shock absorber of claim 4 , wherein the movement of the inner ring member is limited by a step formed in the spool guide or a step formed in the valve body.
6 . The damping force variable valve of a shock absorber of claim 1 , further comprising an outer ring member disposed between the valve body and the elastic member to partition the outer side of the back pressure chamber.
7 . The damping force variable valve of a shock absorber of claim 6 , wherein the movement of the outer ring member is limited by a step formed in the valve body.
8 . The damping force variable valve of a shock absorber of claim 1 , further comprising:
an inner ring member disposed between the valve body and the first spring to partition the inner side of the back pressure chamber; and
an outer ring member disposed between the valve body and the second spring to partition the outer side of the back pressure chamber,
wherein the elastic member includes a first spring and a second spring.
9 . The damping force variable valve of a shock absorber of claim 8 , wherein the movement of the inner ring member is limited by the step formed in the spool guide, and
the movement of the outer ring member is limited by a step formed in the valve body.
10 . The damping force variable valve of a shock absorber of claim 8 or 9 , wherein the first spring and the second spring have different elastic moduli.
11 . A damping force variable valve of a shock absorber, comprising:
a retainer formed with an inflow passage;
a valve body disposed behind the retainer to selectively stop the inflow passage;
a back pressure chamber formed behind the valve body; and
an elastic member pressurizing the valve body to the retainer, behind the valve body,
wherein the valve body moves backward from a position where the inflow passage stops to form a discharge passage connected with the inflow passage, and
the size of the discharge passage varies by the pressure of the working fluid passing through the inflow passage.
12 . The damping force variable valve of a shock absorber of claim 11 , wherein the discharge passage is disposed at the outer circumferential portion of the valve body and the valve body is configured to permit the flow of the working fluid in a back pressure control passage connected with the back pressure chamber from the front inner circumferential portion of the valve body.
13 . The damping force variable valve of a shock absorber of claim 12 , wherein the back pressure control passage is formed in a spool guide penetrating through the valve body and the hollow of the spool guide is mounted with the spool to move forward and backward according to a change in current of a solenoid and controls an opening of the back pressure control passage by the front and back movement of the spool.
14 . The damping force variable valve of a shock absorber of claim 13 , further comprising an inner ring member disposed between the valve body and the elastic member to partition the inner side of the back pressure chamber.
15 . The damping force variable valve of a shock absorber of claim 14 , wherein the movement of the inner ring member is limited by a step formed in the spool guide or a step formed in the valve body.
16 . The damping force variable valve of a shock absorber of claim 13 , further comprising an outer ring member disposed between the valve body and the elastic member to partition the outer side of the back pressure chamber.
17 . The damping force variable valve of a shock absorber of claim 16 , wherein the movement of the outer ring member is limited by a step formed in the valve body.
18 . The damping force variable valve of a shock absorber of claim 11 , wherein the inner ring member stops one side of the back pressure chamber while contacting the rear inner circumferential portion of the valve body, the outer ring member stops the other side of the back pressure chamber while contacting the rear outer circumferential portion of the valve body, and the elastic member includes a first spring and a second spring mounted to pressurize the inner ring member and the outer ring member.
19 . The damping force variable valve of a shock absorber of claim 18 , wherein the first spring and the second spring have different elastic moduli.