| 摘要 |
<p>The invention concerns a brake power assist pneumatic booster, comprising a shell (10), sealingly separated by at least a mobile wall structure (12) into a front chamber (14) and a rear chamber (16) selectively connected to the front chamber (14) or to a high pressure source by a three-way valve (36) actuated by a control rod (30) integral with a plunger (28), subjected to the action of a return spring (38) and capable of sliding in a bore (26) formed in a pneumatic piston (20), integral with the mobile wall (12), the three-way valve (36) comprising a valve element (36) co-operating with a first valve seat (28a) formed on the plunger (28) and with a second valve seat (20a) formed on the pneumatic piston (20), the plunger (28) rear inoperative position being delimited by a limit stop (32) formed at the front end of a sleeve (34) arranged in the pneumatic piston (20) rear tubular part (22). The invention is characterised in that the plunger (28) comprises a cylindrical rear part capable of sliding on the sleeve (34) front end (32), and the control rod (30) return spring (38) is arranged between the pneumatic piston (20) and the plunger (28).</p> |
