Brake systems with master cylinders and single corner actuators
A brake system for actuating a plurality of wheel brakes includes a reservoir and a master cylinder operable during a backup braking mode to generate pressurized hydraulic fluid for hydraulically actuating the wheel brakes, responsive to user manipulation of a brake pedal mechanically connected to the master cylinder. A plurality of single corner actuators is each hydraulically interposed between the master cylinder and a corresponding wheel brake. Each single corner actuator includes a SCA power transmission unit for actuating the respective wheel brake in at least one of a normal non-failure braking mode and a backup braking mode. At least one normally open iso valve is interposed hydraulically between the plunger assembly and the respective first or second MC output for selectively controlling provision of hydraulic fluid to the respective wheel brake from at least one of the plunger assembly and the master cylinder.
1 . A brake system for actuating a plurality of wheel brakes comprising at least first and second wheel brakes, the brake system comprising:
a reservoir;
a master cylinder in fluid communication with the reservoir and operable during a backup braking mode to generate pressurized hydraulic fluid at first and second MC outputs for hydraulically actuating the first and second wheel brakes, respectively, responsive to user manipulation of a brake pedal mechanically connected to the master cylinder, the master cylinder being a dual chamber type master cylinder;
a brake simulator in fluid communication with at least a selected one of the first and second MC outputs and with the reservoir for providing predetermined brake pedal response to the user;
a plurality of single corner actuators, each single corner actuator being hydraulically interposed between a selected one of the first and second MC outputs and a corresponding one of the first and second wheel brakes, each single corner actuator including
a SCA power transmission unit configured for selectively providing pressurized hydraulic fluid at an SCA output for actuating the respective wheel brake in at least one of a normal non-failure braking mode and a backup braking mode, the SCA power transmission unit including an electric PTU motor configured to selectively pressurize the hydraulic fluid by transmitting rotary motion to a plunger assembly of the SCA power transmission unit;
at least one normally open iso valve interposed hydraulically between the plunger assembly and the respective first or second MC output for selectively controlling provision of hydraulic fluid to the respective wheel brake from at least one of the plunger assembly and the master cylinder; and
a check valve interposed hydraulically between the respective first or second MC output and the SCA power transmission unit, a cracking pressure of the check valve permitting pressure release from the SCA power transmission unit due to a predetermined amount of thermal expansion; and
an electronic control unit for controlling at least one SCA power transmission unit responsive to at least one brake pressure signal;
wherein each single corner actuator is indirectly fluidly connected to the reservoir via the master cylinder.
2 . The brake system of claim 1 , wherein the electronic control unit is a first electronic control unit controlling at least a selected one of the normally open iso valves and the brake system includes a second electronic control unit controlling the at least one SCA power transmission unit, wherein both the first and second electronic control units control the respective normally open iso valve and the at least one SCA power transmission unit responsive to at least one brake pressure signal.
3 . The brake system of claim 2 , wherein the second electronic control unit controls at least an other one of the normally open iso valves.
4 . The brake system of claim 1 , wherein the brake pedal is configured to provide a braking signal, in a wired or wireless manner, corresponding to a desired braking action by an operator of the vehicle, wherein the electronic control unit controls at least one of the SCA power transmission unit and the at least one normally open iso valve responsive to the braking signal.
5 . The brake system of claim 1 , wherein the master cylinder includes first and second MC chambers and corresponding first and second MC plungers configured for reciprocal motion therein, the first and second MC chambers each providing pressurized hydraulic fluid at a corresponding first or second MC output.
6 . The brake system of claim 5 , wherein the first and second MC plungers each have substantially the same outer circumference size.
7 . The brake system of claim 6 , wherein the outer circumference of each of the first and second MC plungers includes a sealing groove, the sealing groove including a resilient sealing member for preventing fluid flow therepast when the resilient sealing member is in contact with an inner wall of an MC housing, the resilient sealing member having a cross-sectional shape which is at least one of curved, ovoid, and circular.
8 . The brake system of claim 1 , including third and fourth wheel brakes, each of the third and fourth wheel brakes being actuated by at least one of an electric brake motor and a single corner actuator.
9 . The brake system of claim 1 , wherein each of the single corner actuators is carried by a respective SCA housing, the reservoir and master cylinder are collectively carried by a primary housing, and the primary housing and each SCA housing are all spaced mutually apart from one another.
10 . A brake system for actuating a plurality of wheel brakes comprising at least first and second wheel brakes, the brake system comprising:
a reservoir;
a master cylinder in fluid communication with the reservoir and operable during backup braking mode to generate pressurized hydraulic fluid at first and second MC outputs for hydraulically actuating the first and second wheel brakes, respectively, responsive to user manipulation of a brake pedal mechanically connected to the master cylinder, the master cylinder being a dual chamber type master cylinder;
a brake simulator in fluid communication with at least a selected one of the first and second MC outputs and with the reservoir for providing predetermined brake pedal response to the user;
a plurality of single corner actuators, each single corner actuator being hydraulically interposed between a selected one of the first and second MC outputs and a corresponding one of the first and second wheel brakes, each single corner actuator including
a SCA power transmission unit configured for selectively providing pressurized hydraulic fluid at an SCA output for actuating the respective wheel brake in at least one of a normal non-failure braking mode and a backup braking mode, the SCA power transmission unit including an electric PTU motor configured to selectively pressurize the hydraulic fluid by transmitting rotary motion to a plunger assembly of the SCA power transmission unit;
at least one two-position three-way valve interposed hydraulically between the plunger assembly and the respective wheel brake for selectively controlling provision of hydraulic fluid to the respective wheel brake from at least one of the plunger assembly and the master cylinder; and
a check valve interposed hydraulically between the respective first or second MC output and the SCA power transmission unit, a cracking pressure of the check valve permitting pressure release from the SCA power transmission unit due to a predetermined amount of thermal expansion; and
an electronic control unit for controlling at least one of the three-way valves and the at least one SCA power transmission unit responsive to at least one brake pressure signal;
wherein each single corner actuator is indirectly fluidly connected to the reservoir via the master cylinder.
11 . The brake system of claim 10 , wherein each brake pressure sensor is located directly adjacent a corresponding wheel brake for sensing hydraulic pressure at the corresponding wheel brake and responsively producing the brake pressure signal.
12 . The brake system of claim 10 , wherein the electronic control unit is a first electronic control unit controlling at least a selected one of the three-way valves and the brake system includes a second electronic control unit controlling the at least one SCA power transmission unit, wherein both the first and second electronic control units control the respective three-way valve and the at least one SCA power transmission unit responsive to at least one brake pressure signal.
13 . The brake system of claim 10 , wherein the brake pedal is configured to provide a braking signal, in a wired or wireless manner, corresponding to a desired braking action by an operator of the vehicle, wherein the electronic control unit controls at least one of the three-way valves and the motor-driven master cylinder responsive to the braking signal.
14 . The brake system of claim 10 , wherein the master cylinder includes first and second MC chambers and corresponding first and second MC plungers configured for reciprocal motion therein, the first and second MC chambers each providing pressurized hydraulic fluid at a corresponding first or second MC output.
15 . The brake system of claim 14 , wherein the first and second MC plungers each have substantially the same outer circumference size.
16 . The brake system of claim 15 , wherein the outer circumference of each of the first and second MC plungers includes a sealing groove, the sealing groove including a resilient sealing member for preventing fluid flow therepast when the resilient sealing member is in contact with an inner wall of an MC housing, the resilient sealing member having a cross-sectional shape which is at least one of curved, ovoid, and circular.
17 . The brake system of claim 10 , including third and fourth wheel brakes, each of the third and fourth wheel brakes being actuated by at least one of an electric brake motor and a single corner actuator.
18 . The brake system of claim 10 , wherein each of the single corner actuators is carried by a respective SCA housing, the reservoir and master cylinder are collectively carried by a primary housing, and the primary housing and each SCA housing are all spaced mutually apart from one another.
19 . The brake system of claim 10 , wherein each two-position three-way valve is operative to switch a source of pressurized fluid for the corresponding wheel brake from the corresponding single corner actuator to the corresponding first or second MC output responsive to a loss of electrical power in the brake system.
20 . The brake system of claim 10 , wherein a simulator check valve is interposed hydraulically between the master cylinder and the selected one of the first and second MC outputs which is associated with the brake simulator, the simulator check valve being operative to control flow of pressurized fluid between two or more of the brake simulator, the master cylinder, and a corresponding one of the single corner actuators responsive to pressure in the selected one of the firsts and second MC outputs being at least equal to a predetermined simulator check cracking pressure of the simulator check valve.
21 . The brake system of claim 1 , wherein the check valve only permits flow from the SCA power transmission unit to the master cylinder.
22 . The brake system of claim 1 , wherein each single corner actuator is only indirectly fluidly connected to the reservoir via the master cylinder.
23 . The brake system of claim 10 , wherein the check valve only permits flow from the SCA power transmission unit to the master cylinder.
24 . The brake system of claim 10 , wherein each single corner actuator is only indirectly fluidly connected to the reservoir via the master cylinder.