Brake Actuating Unit For Actuating A Motor Vehicle Brake System

Abstract

Disclosed is a brake actuating unit for actuating a motor vehicle brake system of the ‘brake-by-wire’ type. The system includes a brake booster which is operable in response to the driver's wish both by a brake pedal and by an electronic control unit. A device is provided to decouple a force-transmitting connection between the brake pedal and the brake booster in the ‘brake-by-wire’ operating mode. A master brake cylinder connected downstream of the brake booster, a device to detect a deceleration request of the driver, and a pedal travel simulator which interacts with the brake pedal and due to which a resetting force acting on the brake pedal can be simulated in the ‘brake-by-wire’ operating mode independently of an actuation of the brake booster, and which can be enabled in the ‘brake-by-wire’ operating mode when the force-transmitting connection between the brake pedal and the brake booster is decoupled and can be disabled outside the ‘brake-by-wire’ operating mode. The pedal travel simulator ( 2 ) is enabled and disabled by electromechanical means ( 22, 25 ), electrohydraulic means ( 40, 47 ) or pneumatically operable means ( 96 to 98 ).

1 - 53 . (canceled) 
   
   
       54 . A brake actuating unit for actuating a motor vehicle brake system of a ‘brake-by-wire’ type comprising:
 a brake booster which is operable by a brake pedal and by an electronic control unit, wherein a device is provided to decouple a force-transmitting connection between the brake pedal and the brake booster in the ‘brake-by-wire’ operating mode;   a master brake cylinder connected downstream of the brake booster;   a device to detect a deceleration request of a driver; and   a pedal travel simulator which interacts with the brake pedal and due to a resetting force acting on the brake pedal can be simulated in the ‘brake-by-wire’ operating mode independently of an actuation of the brake booster, and which can be enabled in the ‘brake-by-wire’ operating mode when the force-transmitting connection between the brake pedal and the brake booster is decoupled and can be disabled outside the ‘brake-by-wire’ operating mode, wherein the pedal travel simulator ( 2 ) is enabled and disabled by electromechanical devices ( 22 ,  25 ).   
   
   
       55 . A brake actuating unit according to  claim 54 , wherein the electromechanical devices are drivable by the electronic control unit ( 7 ). 
   
   
       56 . A brake actuating unit according to  claim 54 , wherein the pedal travel simulator ( 2 ) includes a movable simulator unit ( 14 ) which receives at least one simulator spring ( 17 ,  18 ), with the electromechanical devices are formed of a supporting surface ( 22 ) for the simulator unit ( 14 ) and an electromagnet ( 25 ), and with the supporting surface ( 22 ) being maintained by the activated electromagnet ( 25 ) in engagement with the simulator unit ( 14 ) and allowing a translational motion of the simulator unit ( 14 ) when the electromagnet ( 25 ) is inactive. 
   
   
       57 . A brake actuating unit according to  claim 56 , wherein the supporting surface ( 22 ) is designed at a swiveling lever ( 24 ) pivoted within limits. 
   
   
       58 . A brake actuating unit according to  claim 57 , wherein the swiveling lever ( 24 ) is mounted in a point (P) which is arranged radially offset in relation to the longitudinal axis of the simulator Unit ( 14 ). 
   
   
       59 . A brake actuating unit according to  claim 57 , wherein the swiveling lever is configured as a power-transmitting lever. 
   
   
       60 . A brake actuating unit according to  claim 54 , wherein the pedal travel simulator ( 2 ) is not arranged in the flux of forces between the brake pedal ( 1 ) and the brake booster ( 3 ). 
   
   
       61 . A brake actuating unit according to  claim 54 , wherein the pedal travel simulator ( 2 ) includes a movable simulator unit ( 14 ′) which receives at least one simulator spring ( 17 ,  18 ), with the electromechanical devices are formed of the simulator unit ( 14 ′) and an arresting element or transverse slide ( 31 ) being operable by means of an electromagnet ( 25 ′) and arresting the control unit ( 14 ′) in the ‘brake-by-wire’ operating mode, while releasing it outside the ‘brake-by-wire’ operating mode. 
   
   
       62 . A brake actuating unit according to  claim 61 , wherein a cylindrical component ( 30 ) is provided which accommodates at least in part a control housing ( 29 ) of the brake booster ( 3 ) that contains a pneumatic control valve, the simulator unit ( 14 ′), and a resetting spring ( 15 ′) biasing the simulator unit ( 14 ′) in opposition to its actuating direction. 
   
   
       63 . A brake actuating unit according to  claim 61 , wherein the pedal travel simulator ( 2 ) is arranged in the flux of forces between the brake pedal ( 1 ) and the brake booster ( 3 ), preferably coaxially relative to said. 
   
   
       64 . A brake actuating unit according to  claim 54 , wherein the pedal travel simulator includes at least one simulator spring that is configured as at least one leaf spring ( 32 ,  33 ,  34 ) which is compressed in an angular lever ( 35 ) that is rotatable within limits coaxially relative to the brake pedal ( 1 ), and at least one of the electromechanical devices is formed of an arm ( 36 ) of the angular lever ( 35 ) and an arresting element ( 38 ) that is operable by means of an electromagnet ( 25 ″) and prevents the angular lever ( 35 ) from moving in the ‘brake-by-wire’ operating mode. 
   
   
       65 . A brake actuating unit according to  claim 64 , wherein the angular lever ( 35 ) is equipped with an elastic damping means ( 39 ) which is used as a stop for the simulator spring ( 32  to  34 ) and safeguards a progressive characteristic curve of the simulator spring. 
   
   
       66 . A brake actuating unit for actuating a motor vehicle brake system of the ‘brake-by-wire’ type comprising:
 a brake booster which is operable by a brake pedal and by an electronic control unit, and a device is provided to decouple a force-transmitting connection between the brake pedal and the brake booster in the ‘brake-by-wire’ operating mode;   a master brake cylinder connected downstream of the brake booster;   a device to detect a deceleration request of a driver; and   a pedal travel simulator which interacts with the brake pedal and due to a resetting force acting on the brake pedal can be simulated in the ‘brake-by-wire’ operating mode independently of an actuation of the brake booster, and which can be enabled in the ‘brake-by-wire’ operating mode when the force-transmitting connection between the brake pedal and the brake booster is decoupled and can be disabled outside the ‘brake-by-wire’ operating mode, wherein the pedal travel simulator ( 2 ) is enabled and disabled by one or more electrohydraulic devices ( 40 ,  47 ).   
   
   
       67 . A brake actuating unit according to  claim 66 , wherein the one or more electrohydraulic devices is drivable by the electronic control unit ( 7 ). 
   
   
       68 . A brake actuating unit according to  claim 66 , wherein the pedal travel simulator includes at least one simulator spring, and at least one the electrohydraulic devices is formed of a hydraulic cylinder-and-piston arrangement ( 40 ) that is closable by an electromagnetically, pneumatically or electro-pneumatically operable valve ( 47 ), and a force-transmitting element ( 44 ) is interposed between the piston ( 43 ) of the cylinder-and-piston arrangement ( 40 ) and the simulator spring ( 44 ), abutting on which element is a supporting surface ( 42 ) for the simulator spring ( 41 ). 
   
   
       69 . A brake actuating unit according to  claim 68 , wherein the piston-and-cylinder arrangement ( 40 ) and the force-transmitting element ( 44 ) are arranged in a manner radially offset relative to the axis of the brake booster ( 3 ). 
   
   
       70 . A brake actuating unit according to  claim 69 , wherein the piston-and-cylinder arrangement ( 40 ) is disposed in an engine compartment of the motor vehicle. 
   
   
       71 . A brake actuating unit according to  claim 68 , wherein the piston-and-cylinder arrangement ( 40 ) includes a resetting spring ( 15 ) preloading the force-transmitting element ( 44 ) in opposition to the actuating direction of the brake pedal ( 1 ). 
   
   
       72 . A brake actuating unit according to  claim 68 , wherein the brake booster ( 3 ) is a pneumatic brake booster which includes at least one force-transmitting pin ( 45 ) that extends through the booster housing and has a through-bore in which the force-transmitting element ( 44 ) is received. 
   
   
       73 . A brake actuating unit according to  claim 68 , wherein the simulator spring ( 41 ) is designed as at least one leaf spring. 
   
   
       74 . A brake actuating unit according to  claim 68 , wherein the pedal travel simulator ( 2 ) is designed as at least one compression spring ( 52 ,  53 ) which is compressed between the brake pedal ( 1 ) and an angular lever ( 42 ) that is mounted so as to be rotatable within limits coaxially in relation to the brake pedal ( 1 ) and is supported on the force-transmitting element ( 44 ). 
   
   
       75 . A brake actuating unit according to  claim 68 , wherein the simulator spring ( 49 ,  50 ) is arranged in the cylinder-and-piston arrangement ( 40 ) and supported on the piston ( 43 ) of the cylinder-and-piston arrangement ( 40 ). 
   
   
       76 . A brake actuating unit according to  claim 75 , wherein a device ( 51 ) to sense the position of the piston ( 43 ) is provided. 
   
   
       77 . A brake actuating unit according to  claim 68 , wherein the simulator spring is accommodated in a simulator unit ( 14 ) which is arranged in the passenger compartment of the vehicle in a way radially offset relative to the axis of the brake booster ( 3 ). 
   
   
       78 . A brake actuating unit according to  claim 68 , wherein the simulator spring ( ) is received in a simulator unit ( 56 ) which is arranged in the flux of forces between the brake pedal ( 1 ) and the brake booster ( 3 ), preferably coaxially to said. 
   
   
       79 . A brake actuating unit according to  claim 78 , wherein the simulator unit ( 56 ) is configured as a hydraulic piston and forms a closable hydraulic chamber ( 60 ) in a component ( 59 ) which radially embraces at least the simulator unit ( 56 ). 
   
   
       80 . A brake actuating unit according to  claim 79 , wherein the hydraulic chamber ( 60 ) is connected to one of the pressure chambers of the master brake cylinder ( 4 ) or a pressure fluid tank ( 5 ) associated with the master brake cylinder ( 4 ). 
   
   
       81 . A brake actuating unit according to  claim 79 , wherein the hydraulic chamber ( 60 ) is connected to a low-pressure accumulator ( 65 ). 
   
   
       82 . A brake actuating unit according to  claim 79 , wherein the component ( 59 ) is configured as an adapter, which radially embraces the brake booster ( 3 ) at least in part and is used for the supply of air to the brake booster ( 3 ) out of the engine compartment of the vehicle. 
   
   
       83 . A brake actuating unit according to  claim 79 , wherein the hydraulic chamber ( 60 ) is closable by means of an electromagnetically, electro-pneumatically or pneumatically operable valve ( 62 ,  66 ,  67 ). 
   
   
       84 . A brake actuating unit according to  claim 66 , wherein the pedal travel simulator is formed of a hydraulic generating cylinder ( 68 ) operable by the brake pedal ( 1 ) and a hydraulic slave cylinder ( 69 ) connected downstream of the generating cylinder ( 68 ) and having its piston ( 71 ) preloaded by the simulator spring ( 72 ), with the generating cylinder ( 69 ) being closed by way of a connection to a low-pressure accumulator ( 74 ) that can be closed by a valve ( 73 ). 
   
   
       85 . A brake actuating unit according to  claim 84 , wherein the pedal travel simulator is designed in an adapter ( 75 ) which radially embraces the brake booster ( 3 ) at least in part and is used to supply air out of the engine compartment of the vehicle to the brake booster ( 3 ). 
   
   
       86 . A brake actuating unit according to  claim 84 , wherein a device ( 77 ) to sense the position of the slave cylinder piston ( 71 ) is provided. 
   
   
       87 . A brake actuating unit according to  claim 84 , wherein a device ( 76 ) to sense the pressure prevailing in the slave cylinder ( 69 ) is provided. 
   
   
       88 . A brake actuating unit according to  claim 66 , wherein the pedal travel simulator is formed of a simulator spring ( 78 ) compressed between the brake pedal ( 1 ) and a two-armed lever ( 79 ) which is pivoted within limits, whose first arm ( 80 ) forms the supporting surface for the simulator spring ( 78 ) and whose second arm ( 81 ) cooperates with a hydraulic piston ( 83 ) of a piston-and-cylinder arrangement ( 82 ) having its pressure chamber ( 84 ) connected to a hydraulic low-pressure accumulator ( 85 ) by way of a closable hydraulic connection. 
   
   
       89 . A brake actuating unit according to  claim 88 , wherein the first arm ( 80 ) has an opening ( 88 ) which, upon actuation of the brake booster ( 3 ) outside the ‘brake-by-wire’ operating mode, embraces the control housing of the brake booster ( 3 ) at least in part. 
   
   
       90 . A brake actuating unit according to  claim 88 , wherein the two-armed lever ( 79 ) is mounted coaxially to the brake pedal ( 1 ) or offset with respect to the brake pedal ( 1 ). 
   
   
       91 . A brake actuating unit according to  claim 88 , wherein one or more devices to test the movability of the piston ( 83 ) of the piston-and-cylinder arrangement ( 82 ) are provided. 
   
   
       92 . A brake actuating unit according to  claim 91 , wherein at least one of the devices to test the movability of the piston is provided by a tension-force-transmitting connection ( 89 ) between the brake pedal ( 1 ) and the brake booster ( 3 ), and a sensor device ( 95 ) sensing the travel of the piston ( 83 ). 
   
   
       93 . A brake actuating unit according to  claim 91 , wherein at least one of the devices to detect the movability of the piston is formed of a driving unit ( 110 ) which allows actuating the piston ( 83 ) of the piston-and-cylinder arrangement ( 82 ) irrespective of the brake pedal ( 1 ) and a sensor device ( 95 ) sensing the travel of the piston ( 93 ). 
   
   
       94 . A brake actuating unit according to  claim 93 , wherein the driving unit ( 110 ) is configured as an electromechanical or pneumatic driving unit. 
   
   
       95 . A brake actuating unit for actuating a motor vehicle brake system of the ‘brake-by-wire’ type comprising:
 a brake booster operable both by a brake pedal and by an electronic control unit, and a device is provided to decouple a force-transmitting connection between the brake pedal and the brake booster in the ‘brake-by-wire’ operating mode;   a master brake cylinder connected downstream of the brake booster;   a device to detect a deceleration request of a driver, and   a pedal travel simulator which interacts with the brake pedal and due to which a resetting force acting on the brake pedal can be simulated in the ‘brake-by-wire’ operating mode independently of an actuation of the brake booster, and which can be enabled in the ‘brake-by-wire’ operating mode when the force-transmitting connection between the brake pedal and the brake booster is decoupled and can be disabled outside the ‘brake-by-wire’ operating mode, wherein the pedal travel simulator ( 2 ) is enabled and disabled a pneumatically operable device.   
   
   
       96 . A brake actuating unit according to  claim 95 , wherein the pneumatically operable device can be operated by a vacuum source provided in the vehicle. 
   
   
       97 . A brake actuating unit according to  claim 95 , wherein the pedal travel simulator ( 2 ) includes a movable simulator unit ( 90 ) which receives at least one simulator spring ( 91 ,  92 ), and the pneumatically operable device is formed of a supporting surface for the simulator spring ( 91 ,  92 ) being designed in the simulator unit ( 90 ) as well as an arresting element ( 97 ) which is operable by a vacuum box ( 98 ) and arrests the simulator unit ( 90 ) in the ‘brake-by-wire’ operating mode and releases it outside the ‘brake-by-wire’ operating mode. 
   
   
       98 . A brake actuating unit according to  claim 97 , wherein the pedal travel simulator ( 2 ) is arranged in the flux of forces between the brake pedal ( 1 ) and the brake booster ( 3 ). 
   
   
       99 . A brake actuating unit according to  claim 98 , wherein a cylindrical component ( 90 ) is provided which accommodates at least in part a control housing of the brake booster ( 3 ) that comprises a pneumatic control valve, the simulator unit ( 90 ), and a resetting spring ( 94 ) preloading the simulator unit ( 90 ) in opposition to its actuating direction. 
   
   
       100 . A brake actuating unit according to  claim 95 , wherein one or more devices to produce a hysteresis are provided. 
   
   
       101 . A brake actuating unit according to  claim 100 , wherein the one or more devices to produce the hysteresis are designed so that, with rising stroke of the pedal travel simulator ( 2 ), friction forces are generated in addition to the force of the simulator spring ( 17 ,  18 ,  78 ) which counteract the actuating force acting on the brake pedal ( 1 ). 
   
   
       102 . A brake actuating unit according to  claim 101 , wherein the one or more devices to produce the hysteresis are formed of a force-transmitting lever ( 99 ) connected to the brake pedal ( 1 ) and a friction member ( 100 ) which abuts on the force-transmitting lever ( 99 ) by the action of the simulator spring ( 78 ) and cooperates with a friction surface ( 101 ). 
   
   
       103 . A brake actuating unit according to  claim 102 , wherein the force-transmitting lever ( 99 ) and the friction member ( 100 ) include inclined abutment surfaces ( 105 ,  106 ) which are so configured that a force component develops when the pedal travel simulator ( 2 ) is actuated, urging the friction member ( 100 ) against the friction surface ( 101 ). 
   
   
       104 . A brake actuating unit according to  claim 102 , wherein the friction member ( 100 ) is arranged on a transmission lever ( 104 ) being supported on the force-transmitting lever ( 99 ) in such a fashion that boosting of the force component occurs which is produced upon actuation of the pedal travel simulator ( 2 ) and urges the friction member ( 100 ) against the friction surface ( 101 ). 
   
   
       105 . A brake actuating unit according to  claim 102 , wherein the one or more devices to produce the hysteresis is arranged in a housing ( 103 ) which is pivoted coaxially to the brake pedal ( 1 ) on the axis of rotation thereof, with the housing ( 103 ) having an arm ( 102 ) being supported on the means for activating and deactivating the pedal travel simulator ( 2 ).