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US 5,848,827 AGranted
Braking assistance pneumatic servomotor with improved valve
AssigneeBosch Systems De Freinage
InventorRoland Levrai
Life of this patent
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AssigneeBosch Systems De Freinage
InventorRoland Levrai
Estimating the term…
A pneumatic brake booster for providing braking assistance. The brake booster has a housing (10) with an axis of symmetry (X--X') separated sealingly by at least one movable partition (12) to define at least a first chamber (14) connected permanently to a source of low pressure and at least a second chamber (16). The second chamber (16) being selectively connected to the first chamber (14) or a source of high pressure through a three way valve structure actuated by a control rod (30,130). The three way valve structure have a valve member (36,136) which cooperates through an a first annular face (40,140) with a first annular valve seat (34,134) formed on a plunger (28,128) which slides in a bore (26,126) of a piston (20,90). The annular face (40,140) of the valve member (36,136) being urged forward in the direction of the annular valve seat (34,134) by a valve spring (42,142). The three way valve structure further includes a second valve member (46,146) which cooperates through an annular face (50,150) with a second annular valve seat (44,144) formed on the plunger (28,128). The annular face (50,150) of the second valve member (46,146) being urged rearwards in the direction of the second annular valve seat (44,144) by a second valve spring (52,152).
A pneumatic booster for braking assistance, comprising an envelope having an axis of symmetry, separated sealingly by at least one movable partition structure into at least a first chamber connected permanently to a source of low pressure, and at least a second chamber connected selectively to said first chamber or to a source of high pressure through a three way valve means actuated by a control rod, said three way valve comprising a valve member co-operating through an annular face with a first annular valve seat formed on a plunger which slides in a bore of a piston, said annular face of said valve member being urged forwards in the direction of said first annular valve seat by a valve spring, characterised in that said three way valve comprises a second valve member which co-operates through an annular face with a second annular valve seat formed on the plunger, the annular face of the second valve member being urged rearwards in the direction of said second annular valve seat by a second valve spring.
Dependencies are inferred from the claim text.