Vacuum source device for vacuum booster for vehicles

Claim 1

A vacuum source device including dual check valves in combination with an intake system for a vacuum booster for vehicles said vacuum booster including a shell defining a vacuum chamber, said vacuum source device comprising: (a) an air ejector including a body having a front surface, a rear surface and a side surface; (b) an air inlet at the front surface of said body with an air inlet communicating with the atmosphere; (c) an air outlet on the rear surface to lead to an opposed vacuum pick up port opening to the portion of the engine intake system downstream of a throttle valve; (d) a suction port formed on the side surface and communicating with the vacuum chamber of the vacuum booster; (e) a pressure reduction chamber communicating with said air inlet and also communicating with said suction port via a passage and an outlet chamber communicating with said air outlet; (f) a diffuser connecting between said reduction chamber and said outlet chamber; (g) a by-pass formed in said body for connecting between said outlet chamber and said suction port while detouring said diffuser of the air ejector; (h) a first check valve disposed in said by-pass passage; (i) a second check valve disposed in a valve chamber formed at a juncture between said suction port and said by-pass passage, and being in series flow relationship with said first check valve whereby said air ejector and said first and second check valves together constitute a unit, said suction port serves as an opening of said valve chamber for accommodating said second check valve and said unit is integrally attached to a front surface of the booster shell such that said opening meets an opening formed in the booster shell and that the portion of the booster shell surrounding the booster opening serves as a valve seat for the second check valve.