Eccentric cam brake booster
First Claim
1. An electrically boosted vehicle brake system, comprising:
- a master cylinder including a piston, a piston return spring and a piston actuating rod extending from the cylinder, the piston actuating rod being movable from a quiescent position against return spring bias to apply braking fluid pressure to individual wheel brake actuators;
a cam rotatable about an axis and having a variable radius cam surface for engaging and moving the actuating rod; and
an electric motor coupled to the cam and operable to rotate the cam and move the actuating rod.
1 Assignment
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Accused Products
Abstract
An electric power booster (12) where driver command is monitored by a transducer (38) on an input rod (34). This signal is converted to the appropriate voltage/current and operates an electric motor (42). The motor output shaft (68) is connected to a planetary gear reducer (72) appropriately sized to provide no more than +/−1/4 turn of an eccentric cam (14). Two master cylinders (16, 18) power piston rods (22, 24) ride diametrically opposed on the cam surface (20). As the cam rotates the piston rods are forced out pressurizing the respective hydraulic circuits and thereby providing fluid to each brake circuit (28, 30). In the event of power failure as well as to augment the output of the motor, the input rod is mechanically linked directly to the cam offset from the center allowing the driver to manually rotate the cam thereby pressurizing the brake circuits.
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Citations
18 Claims
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1. An electrically boosted vehicle brake system, comprising:
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a master cylinder including a piston, a piston return spring and a piston actuating rod extending from the cylinder, the piston actuating rod being movable from a quiescent position against return spring bias to apply braking fluid pressure to individual wheel brake actuators; a cam rotatable about an axis and having a variable radius cam surface for engaging and moving the actuating rod; and an electric motor coupled to the cam and operable to rotate the cam and move the actuating rod. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An electrically boosted vehicle brake system, comprising:
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a first hydraulic braking circuit for a first set of vehicle wheels including a master cylinder having a cylindrical bore, a piston reciprocably located within the bore, and a piston actuating rod extending from the master cylinder; a second hydraulic braking circuit for a second set of vehicle wheels including a second master cylinder having a second cylindrical bore, a second piston reciprocably located within the second bore, and a second piston actuating rod extending from the second master cylinder; said bore and said second bore being generally coaxial with said actuating rod and said second actuating rods extending from the respective master cylinders toward one another; and an electromechanical brake actuating mechanism including a variable width member interposed between the piston rods and movable from a first quiescent position to increase the separation between the actuating rods thereby applying braking fluid pressure to both hydraulic braking circuits. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An electrically boosted vehicle brake system, comprising:
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a first master cylinder including a first piston, and a first piston actuating rod extending from the first cylinder, the first piston actuating rod being movable from a quiescent position to apply braking fluid pressure to a first set of wheel brake actuators; a second master cylinder including a second piston, and a second piston actuating rod extending from the second cylinder, the second piston actuating rod being movable from a quiescent position to apply braking fluid pressure to a second set of wheel brake actuators; said actuating rod and said second actuating rods extending from the respective master cylinders toward one another; a cam rotatable about an axis and having a variable radius cam surface for engaging and moving the actuating rods away from one another; and an operator brake pedal and linkage coupled to the cam remote from the axis and operable in response to operator applied brake pedal pressure to rotate the cam thereby applying braking fluid pressure to both sets of wheel brake actuators. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification