感載比例閥（SABS ），從本質上講，SABS只是一套液壓機械裝置；感載閥的作用在于保證行駛過程中前后輪負荷的合適比例并確保在汽車緊急制動時后輪不抱死。感載比例閥利用車身與車橋之間的距離變化(外界作用力)來改變彈簧的預緊力，隨著車輛載荷的增加，相應地進行調整，使得在任何載荷條件下都能得到一個近似理想的制動力分配 。它安裝在制動總泵與后輪制動分泵之間的管道上，由殼體、柱塞、閥門、彈簧等組成。殼體進油孔與制動總泵出油孔相通，出油孔與車輪制動分泵相通。當外界作用力小時，感載比例閥的柱塞在彈簧預緊力的作用下被推至最右邊，兩孔相通，總泵與分泵壓力相等。當外界作用力大于彈簧 預緊力，迫使柱塞左移，令柱塞與閥門接觸并關閉了閥門，切斷總泵通向分泵的通道；若外界作用力壓力繼續增大，又會使柱塞右移，柱塞與閥門脫離接觸，閥門又被打開，總泵與分泵又相通。這樣比例閥反復動作使分泵的液壓不斷得到調整，也即不斷調整了后輪制動力。
load sensing proportional valve (SABS), essentially, SABS is a set of hydraulic mechanical device; load sensing valve role is to ensure that the process of moving front and rear wheel load and ensure the proper proportion in the car when the rear emergency brake without locking. The load sensing valve by the change in distance between the body and the axle (external force) to change the spring preload, as the vehicle load increases, adjusted accordingly, which can get an approximate ideal braking force distribution in any load condition. The utility model is composed of a casing, a plunger, a valve, a spring, etc. the utility model is arranged on a pipeline between the brake master pump and the rear wheel brake branch pump. The oil inlet hole of the casing is communicated with the oil outlet hole of the brake master pump. When the outside force, the feeling of the proportion of the plunger valve under the action of the spring preload is pushed to the right side, the two holes are interlinked, the total pump and pump pressure equal. When the external force is greater than the spring preload, forcing the plunger moves to the left, to make contacts with the valve plunger and closed the valve, cut off the pump to pump the channel; if the pressure continues to increase the external force, and can make the right plunger, plunger out of contact with the valve, the valve has been opened, the total pump and pump connected. This proportion of the repeated action of the valve so that the hydraulic pump constantly adjusted, that is, constantly adjust the rear wheel power.