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US 5,667,284 AGranted
Manually backdrivable ball screw assisted braking system
AssigneeGeneral Motors Corporation
InventorsDavid Bernard Drennen, Ryan Lovell Wright
Life of this patent
Estimating the term…
Abstract
A manually backdrivable ball screw assisted braking system includes a ball drive operated by a reversible electric motor to effect linear translation of the piston resulting in selected pressurization of a wheel brake. The ball drive is assisted in operation by a manually backdrivable ball screw assembly operated by actuation of a hydraulic master cylinder by the manual application of force to the brake pedal.
Claims8
A braking system comprising:
- an actuator having a screw drive including a drive screw connected to a first piston so that the drive screw and first piston are translatable linearly through the actuator;
- a drive nut disposed about the drive screw and engaging a first gear and a second gear and being rotatable and fixed against linear translation within the actuator;
- an electric motor engaging the first gear and being reversibly rotatable to rotate the first gear and the drive nut;
- an assist gear engaging the second gear and being rotatable to rotate the second gear and the drive nut;
- a threaded shaft engaging the assist gear;
- a nonrotatable nut disposed about and engaging the threaded shaft;
- a second piston connected to the nonrotatable nut wherein the second piston is linearly translatable to effect rotation of the drive nut and linear translation of the first piston.
4 more elements
A braking system comprising:
- a wheel brake;
- a master cylinder;
- a brake line extending between the wheel brake and the master cylinder;
- an actuator interposed in the brake line including a first variable chamber communicating with the wheel brake through the brake line and a second variable chamber communicating with the master cylinder through the brake line;
- wherein the actuator includes a first piston operated by a screw driven mechanism to automatically adjust the first variable chamber and a second piston operating an assist screw drive, the assist screw drive engaging the screw driven mechanism so that a first pressure effected in the second variable chamber by operation of the master cylinder moves the assist screw drive to drive the screw driven mechanism generating a second pressure in the first variable chamber.
2 more elements
An actuator comprising:
- a housing having a first variable chamber and a second variable chamber;
- a first piston operated by a screw driven mechanism to automatically adjust the first variable chamber and a second piston operating an assist screw drive, the assist screw drive engaging the screw driven mechanism so that a first pressure selectively effected in the second variable chamber moves the assist screw drive to drive the screw driven mechanism generating a second pressure in the first variable chamber;
- the screw driven mechanism including a rotatable nut with a first drive gear connected to the rotatable nut;
- and
- the assist screw drive including a rotatable shaft with an assist drive gear fixed on the rotatable shaft and meshing with the drive gear.
2 more elements
Dependencies are inferred from the claim text.