Crash-protected vacuum brake booster for motor vehicles

Abstract

In order to improve the deformation behavior of a vacuum brake booster provided with force transmission pins that are used to transmit forces onto a body splashboard of a motor vehicle, the invention discloses that the force transmission pins are made up of two sections having different strength. To achieve a sufficiently low strength when a fastening screw is used for a first section, the first section is embodied as a hollow body, and the fastening screw extends only over the length of a second section of the pin. Because the first section is configured as a hollow body, the screw arranged in the second section can be actuated through the first section.

1 - 7 . (canceled)  
   
   
       8 . Vacuum brake booster for motor vehicles with a booster housing including two opposed housing shells, with at least one movable wall subdividing the interior of the booster housing into two chambers, as well as with at least one force transmission pin that extends in parallel to the longitudinal axis of the vacuum brake booster from a first housing shell to the second housing shell arranged on the opposite side of the movable wall and is sealed in relation to the movable wall, and at the end of which force transmission pin fastening elements for a vehicle body wall or a master brake cylinder connected downstream of the vacuum brake booster are designed, with the force transmission pin including at least one first section and one second section, wherein the material cross-section of the first section is chosen to be small compared to the material cross-section of the second section to such an extent that it decreases its length extending in the longitudinal direction of the pin when a predetermined force is exceeded.  
   
   
       9 . Vacuum brake booster as claimed in  claim 8 , wherein the first section is configured as a hollow cylinder, whose wall thickness is chosen so be so thin that the first section will reduce its length extending in the longitudinal direction of the pin when a predetermined force is exceeded.  
   
   
       10 . Vacuum brake booster as claimed in  claim 9 , wherein the pin comprises a second section designed as a hollow cylinder, and in that a fastening screw extends through the second section and is supported with its screw head at least indirectly on the end surface of the section that forms the second cylinder and, with its threaded other end projects through the second housing shell close to the body wall.  
   
   
       11 . Vacuum brake booster as claimed in  claim 10 , wherein the first and the second section are integrally formed or non-detachably interconnected.  
   
   
       12 . Vacuum brake booster as claimed in  claim 11 , wherein the first section is provided with a projection made by deformation, with pressure forces that act on the first housing shell being supported on said projection.  
   
   
       13 . Vacuum brake booster for motor vehicles with a booster housing including two opposed housing shells, with at least one movable wall subdividing the interior of the booster housing into two chambers, as well as with at least one force transmission pin that extends in parallel to the longitudinal axis of the vacuum brake booster from a first housing shell to the second housing shell arranged on the opposite side of the movable wall and is sealed in relation to the movable wall, and at the end of which force transmission pin fastening elements for a vehicle body wall or a master brake cylinder connected downstream of the vacuum brake booster are designed, with the force transmission pin including at least one first section and one second section, wherein the first section and the second section are formed of hollow cylinders, that the first and the second section are fixed in position to each other in the longitudinal direction of the pin by a holding connection, that the holding connection is disengaged when a predefined force that acts in the longitudinal direction of the pin is exceeded and the two sections are telescopically displaced into each other, and that a fastening screw projects through the second section and is supported with its screw head on the end face of the cylinder that forms the second section and with its threaded, other end projects through the second housing shell close to the body wall.  
   
   
       14 . Vacuum brake booster as claimed in  claim 13 , wherein the first section is provided with a projection that is formed by deformation and on which pressure forces that act on the first housing shell are supported.