Patent ID: 6896337
Filing Date: 2005-05-24
Classification: B60T

Abstract:
1. A brake booster ( 12 ) having a housing with an interior separated into at least a first chamber ( 26 , 26 ′) and a second chamber ( 28 , 28 ′) by a wall ( 21 ) connected to a hub ( 50 ), said hub ( 50 ) having a cylindrical body ( 54 ) with an axial bore ( 55 ) that extends from a first end ( 56 ) to a second end ( 58 ), a control valve ( 100 ) located in said axial bore ( 55 ) for sequentially connecting said first chamber ( 26 , 26 ′) with said second chamber ( 28 , 28 ′) to provide for the equalization of fluid pressure therein in a first mode of operation and interrupting communication between said first ( 26 , 26 ′) and second ( 28 , 28 ′) chambers while connecting said second chamber ( 28 , 28 ′) to a surrounding environment to allow air to enter into said second chamber ( 28 , 28 ′) and create a pressure differential across said wall ( 21 ) in response to an operational signal to defining a second mode of operation, said pressure differential acting on said wall ( 21 ) to develop an output force that is communicated through said hub ( 50 ) to an output push rod ( 222 ), said output force, after overcoming a return spring ( 240 ), moving said output push rod ( 222 ) to supply pistons located in a master cylinder ( 13 ) with an operational input to pressurize fluid in the master cylinder ( 13 ), said pressurized fluid from the master cylinder ( 13 ) being communicated to wheel brakes ( 14 , 14 ′ 18 , 18 ′) to effect a brake application, said brake booster ( 12 ) being characterized by a first input member ( 30 ) connected to said control valve ( 100 ) and responsive to an operator input for moving said control valve ( 100 ) from said first mode to said second mode to develop a corresponding first brake application, a second input member ( 200 ) being connected to said control valve ( 100 ) and responsive to an electrical input under the control of an electronic control unit (ECU)( 40 ) for moving said control valve ( 100 ) from said first mode to said second mode to develop a corresponding second brake application and switch means ( 300 ) responsive to movement of said control valve ( 100 ) by said second input member ( 200 ) to provide said ECU ( 40 ) with a first signal confirming the development of said second brake application and responsive to movement of said control valve ( 100 ) by said first input member ( 30 ) to provide said ECU ( 40 ) with a second signal whereby said electrical input to said second input member ( 200 ) is terminated and immediate development of said first brake application is initiated, said control valve ( 100 ) having a poppet assembly ( 101 ) with a flexible tubular section ( 102 ) secured to a collar assembly ( 108 ) to define a unitary structure, said tubular section having a bead ( 104 ) on a first end that is secured to said cylindrical body ( 54 ) by a first retainer ( 120 ) that is fixed to said cylindrical body ( 54 ) and a lip ( 106 ) on a second end that is secured to a collar ( 108 ) assembly, said collar assembly ( 108 ) having a flange ( 110 ) on a first end and a second end that is secured to said second end of said flexible tubular section ( 102 ), said control valve ( 100 ) having a washer ( 112 ) that is integral with said, lip ( 106 ) and a first annular surface ( 114 ) on said lip ( 106 ) that defines a first seat while said collar assembly ( 108 ) has a second annular surface ( 118 ) thereon that defines a first face, said control valve ( 100 ) including a first spring ( 130 ) that is located between said first retainer ( 120 ) and said washer ( 108 ) for urging said second annular surface ( 118 ) on said collar assembly ( 108 ) toward a second seat ( 62 ) in said cylindrical body ( 54 ), said control valve ( 100 ) having a first plunger ( 132 ) with a shaft that extends from a base on a first end ( 136 ) to a second end ( 140 ), said base having a stepped bore ( 152 ) therein for receiving a head ( 31 ) on a push rod ( 30 ) of said first input member, said shaft having a first diameter ( 134 ) for said base, a second diameter ( 138 ) adjacent said second end ( 140 ) and a third diameter ( 142 ) located there between, a cylindrical member ( 154 ) that surrounds said base of said shaft having a third annular surface ( 166 ) thereon that defines a second face ( 159 ), and a second spring ( 164 ) that is located in said stepped bore ( 152 ) of said base for urging said second face ( 159 ) away from said first end ( 136 ) of said shaft and toward said first seat, a third spring ( 170 ) that is located between said first retainer ( 120 ) and said push rod ( 30 ) for urging said first plunger ( 132 ) toward said first retainer ( 120 ) to bring said second face ( 159 ) into engagement with said first seat while moving said second annular surface ( 118 ) away from said second seat ( 62 ) during said first mode of operation, said second input member ( 200 ) having a second plunger ( 202 ) that surrounds said third diameter ( 142 ) on said shaft of said first plunger ( 132 ), a solenoid ( 201 ) that is concentric to said second plunger ( 202 ) and linkage ( 400 ) that connects said second plunder ( 202 ) with said cylindrical member ( 156 ) that surrounds said base of said first plunger ( 132 ), said solenoid ( 201 ) on receipt of said electrical input acting on and moving said second plunger ( 202 ) within said axial bore ( 55 ) and correspondingly moving said cylindrical member ( 156 ) and said second face on said third annular surface ( 166 ) away from said first seat after said first spring ( 130 ) moves said second face on said second annular surface ( 118 ) on said collar into engagement with said second seat ( 62 ) to allow air to be communicated to said second chamber ( 28 , 28 ′) and initiate development of said second brake application during said second mode of operation, said second input member ( 200 ) in developing said second mode of operation moving said hub ( 50 ) while said first plunger ( 132 ) initially remains stationary such that a switch plunger ( 302 ) on said switch means ( 300 ) is located on said second diameter ( 138 ) of said shaft to provide said first signal to said ECU.