Damping force controlling valve assembly for shock absorber

1. A damping force controlling valve assembly for a shock absorber, comprising:

a main body part of a retainer having an inlet passage connected to a high pressure side of the shock absorber;

a main valve generating a damping force while resisting a working fluid flowing in through the inlet passage;

a spool rod part interacting with a spool inserted thereinto and supplying a working fluid through a connection port to a back-pressure chamber provided at the rear of the main valve;

a solenoid part controlling a position of the spool to adjust a pressure of the back-pressure chamber; and

an auxiliary valve disposed upstream of the main valve to generate a damping force in an extremely low speed section in advance of the main valve.

2. The damping force controlling valve assembly according to claim 1 , wherein the auxiliary valve comprises:

a body in which a flow passage is formed to allow a working fluid flow from a high pressure side to the inlet passage; and

a plurality of disks disposed under the body to cover the flow passage,

wherein at least one of the disks is a slit disk.

3. The damping force controlling valve assembly according to claim 2 , wherein the auxiliary valve comprises:

one slit disk allowing the working fluid to pass through a slit thereof in the extremely low speed section; and

one or more lower disks disposed under the slit disk and having no slit.