Gm Global Technolgoy Operations, Inc.

Malvin L Schubert

John R Coleman

An apparatus is provided for connecting a master cylinder to a brake booster of the type which has a shell with a planar front surface and a plurality of threaded studs displayed about the bore and projecting from the planar front surface. The master cyliner has a necked down end portion defining a shoulder facing the booster. The master cylinder has a circumferential extending groove provided in the necked down end portion and spaced longitudinally from the shoulder. An adapter has a central aperture to receive the necked down end portion of the master cylinder and a plurality of apertures which register with the plurality of threaded studs. A lock ring or other locking device is received in the groove of the master cylinder and effective to lock the adapter to the master cylinder and in engagement with the shoulder. A plurality of threaded nuts are installed on the threaded studs to retain the adapter in engagement with the planar surface of the booster shell.

Master cylinder attachment adapter

The floating control valve of a vacuum operated booster has a recess or groove and a smaller steel washer which allows the seating portion of the control valve to seek its own plane. The insert is linearly aligned with the air valve seat. The outer portion of the control valve aligned with the vacuum valve seat on the power piston is not supported by the steel insert. The groove is positioned radially between the portions of the floating control valve engaging the two seats and may be on either the front or the rear side of the floating control valve.

Vacuum suspended brake booster control valve

A hydraulic pressure actuated power brake system having a hydraulic power booster with operating pressure on both sides of the power piston power wall. The booster is therefore hydraulic pressure suspended so that the hydraulic pump of the system need not be operating to maintain this pressure while the booster is inactive. An accumulator is also charged by this pressure to provide power brake booster operation for several booster actuations without recharging by the pump. When the pump is operating, a pilot valve which is sensitive to a drop in booster operating pressure will control charging or recharging the accumulator and booster from pressure generated by the pump to maintain a desired charge pressure. A pressure relief valve will also prevent overcharging of the accumulator and booster. A check valve prevents loss of booster operating pressure toward the pump outlet if the pump pressure falls below the charged pressure. A spool control valve in the booster modulates pressure on the downstream power piston side, returning fluid to the pump reservoir and creating a controlled pressure differential across the piston power wall to actuate the booster. A mechanical follow-through is provided for manual operation when booster operating pressure is depleted.

Hydraulic power brake system and hydraulic brake booster and controls

A hydraulic pressure actuated power brake system having a hydraulic power booster with operating pressure on both sides of the power piston power wall. The booster is therefore hydraulic pressure suspended so that the hydraulic pump of the system need not be operating to maintain this pressure while the booster is inactive. An accumulator is also charged by this pressure to provide power brake booster operation for several booster actuations without recharging by the pump. When the pump is operating, a pilot valve which is sensitive to a drop in booster operating pressure will control charging or recharging the accumulator and booster from the pressure generated by the pump to maintain a desired charge pressure. A pressure relief valve will also prevent overcharging of the accumulator and booster. A check valve prevents loss of booster operating pressure toward the pump outlet if the pump pressure falls below the charged pressure. A spool control valve in the booster modulates pressure on the downstream power piston side, returning fluid to the pump reservoir and creating a controlled pressure differential across the piston power wall to actuate the booster. A mechanical follow-through is provided for manual operation when booster operating pressure is depleted.

A booster having a vacuum powered booster section and a hydraulic powered booster section which are normally actuated together to supply boosted force to a master cylinder. When the air valve of the vacuum booster section is operated to cause atmospheric air to enter the variable pressure chamber of the vacuum booster, it also engages and moves the hydraulic booster control valve to restrict hydraulic fluid flow therethrough, causing the hydraulic booster section control valve to be actuated to create a hydraulic pressure differential across the power wall of the hydraulic booster section. Both booster sections deliver boosted force through the output member of the hydraulic booster section to the master cylinder. Either booster section is operable when for any reason there is no power available for actuation of the other booster section. The hydraulic booster section has an integral reaction piston within its control valve, permitting simple reaction system changes depending upon the calibration required for each different vehicle. The hydraulic booster section control valve is almost completely balanced, lowering the force required to push the hydraulic control valve member to the hydraulic control valve seat.

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Kettering, OH, United States of America

Malvin L Schubert