SOFTNESS ADJUSTING DEVICE FOR VEHICLE SEAT, VEHICLE SEAT, AND VEHICLE

A softness adjusting device for a vehicle seat is arranged under the seat cover of the vehicle seat and includes a soft inflatable bag and a valve component arranged outside the soft inflatable bag. The valve component includes a throttle valve and a one-way check valve. The throttle valve is configured to block or communicate a gas in the soft inflatable bag from or with an external air source. The one-way check valve provides a flow direction from outside to inside and is configured to fill the soft inflatable bag with the external air source when the pressure of the external air source is greater than air pressure in the cavity of the soft inflatable bag. The soft inflatable bag is filled with at least one flexible filler.