Brake system with motor-driven master cylinder and wheel-side pressure sensor

Abstract

The invention relates to a brake system having a master cylinder driven by an electric motor and a wheel-side pressure sensor. A brake system includes a reservoir and a motor-driven master cylinder for actuating a plurality of wheel brakes. The secondary power transfer unit provides pressurized hydraulic fluid at the first PTU output and the second PTU output for actuating the wheel brakes in at least one of a normal non-fail braking mode and a standby braking mode. The secondary power transmission unit includes a PTU motor and at least two pump pistons. At least two brake pressure sensors are provided. Each brake pressure sensor is positioned directly adjacent a corresponding wheel brake for sensing hydraulic pressure at the corresponding wheel brake and responsively generating a brake pressure signal. An electronic control unit is provided for controlling at least one of the secondary power transmission unit and the master cylinder in response to at least one brake pressure signal. The secondary power transfer unit is directly fluidly connected to the reservoir.

Description

Technical Field

[0001] The present disclosure relates to apparatus and methods for using a braking system having a motor-driven master cylinder and wheel-side pressure sensors, and more particularly, to methods and apparatus for a braking system in which at least one hydraulic pressure sensor is positioned adjacent to at least one wheel. Background Art

[0002] The braking system may include an anti-lock control including a hydraulic brake pressure generator, a brake pressure regulator, a sensor and an electronic circuit, the brake pressure regulator being arranged in a pressure fluid conduit between the brake pressure generator and the wheel brakes and being used to change the brake pressure by changing the volume of a chamber containing a hydraulic fluid, the sensor being used to determine the wheel rotation behavior, the electronic circuit being used to process the sensor signal and being used to generate a brake pressure control signal. The braking system may also include both an anti-lock control and a traction slip control, the traction slip control being able to use the brake pressure regulator to control vehicle braking.

[0003] Descriptions of prior art braking systems are provided in U.S. Patent No. 10,730,501, issued to Blaise Ganzel on August 4, 2020, and entitled “Vehicle Braking System with Auxiliary Pressure Source,” U.S. Patent Application Publication No. 2020 / 0307538, published on October 1, 2020 by Blaise Ganzel, and entitled “Braking System with Multiple Pressure Sources,” and U.S. Patent Application No. 17 / 400,250, filed by Blaise Ganzel on August 12, 2021, and entitled “Apparatus and Method for Controlling a Hydraulic Braking System Including Manual Push,” all of which are incorporated herein by reference in their entirety for all purposes. Summary of the invention

[0004] In one aspect, alone or in combination with any other aspect, a braking system for actuating a plurality of wheel brakes including a first pair of wheel brakes and a second pair of wheel brakes is described. The braking system includes a reservoir and a motor-driven master cylinder, which can be operated to generate brake actuation pressure at a first MC output and a second MC output by actuation of a motor of the master cylinder during a normal non-fault braking mode, for hydraulically actuating the first pair of wheel brakes and the second pair of wheel brakes, respectively. The secondary power transfer unit is configured to selectively provide pressurized hydraulic fluid at a first PTU output and a second PTU output, for actuating the first pair of wheel brakes and the second pair of wheel brakes in at least one of a normal non-fault braking mode and a backup braking mode. The secondary power transfer unit includes a PTU motor configured to selectively pressurize the hydraulic fluid by transmitting rotational motion to at least two pump pistons. Each pump piston provides pressurized hydraulic fluid to a corresponding one of the first PTU output and the second PTU output. Each of the first PTU output and the second PTU output provides fluid to a corresponding pair of wheel brakes in the first pair of wheel brakes and the second pair of wheel brakes. At least two brake pressure sensors are provided. Each brake pressure sensor is positioned directly adjacent to a corresponding wheel brake for sensing a hydraulic pressure at the corresponding wheel brake and responsively generating a brake pressure signal. An electronic control unit is provided for controlling at least one of a secondary power transfer unit and a master cylinder in response to at least one brake pressure signal. The secondary power transfer unit is directly fluidically connected to the reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] For a better understanding, reference may be made to the accompanying drawings, in which:

[0006] Figure 1 is a schematic hydraulic diagram of an exemplary brake system according to one aspect of the present invention;

[0007] Figure 2 is in the first alternative configuration Figure 1 A schematic hydraulic diagram of an exemplary braking system of; and

[0008] Figure 3 is in the second alternative configuration Figure 1 Schematic hydraulic diagram of an exemplary braking system. DETAILED DESCRIPTION

[0009] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0010] The present invention comprises, consists of, or consists essentially of any combination of the following features.

[0011] Figures 1 to 3 Schematically illustrated are three configuration options for an exemplary braking system 100 for actuating a plurality of wheel brakes 102. The braking system 100 is shown here as a hydraulic braking system, wherein a braking force is applied to the braking system 100 using fluid pressure. The braking system 100 can be suitably used on a ground vehicle, such as a motor vehicle having four wheels, wherein a wheel brake is associated with each wheel. In addition, the braking system 100 can be provided with other braking functions, such as anti-lock braking (ABS) and other slip control features, to effectively brake the vehicle. The components of the braking system 100 can be housed in one or more blocks or housings. The block or housing can be made of a solid material, such as aluminum, which has been drilled, machined or otherwise formed to accommodate various components. Fluid conduits can also be formed in the block or housing.

[0012] exist Figures 1 to 3 In the embodiment of the braking system 100 shown, there are four wheel brakes 102, each of which may have any suitable wheel brake structure that is electrically operated and / or operated by applying a pressurized brake fluid. Each wheel brake 102 may include, for example, a brake caliper mounted on the vehicle to engage a friction element (e.g., a brake disc) that rotates with the wheel to achieve braking of the associated wheel. The wheel brakes 102 may be associated with any combination of the front wheels and rear wheels of the vehicle on which the corresponding braking system 100 is installed. For example, each braking system 100 may be configured as a vertically separated or diagonally separated system. Although a person of ordinary skill in the art can easily provide a suitable braking device for a specific use environment, for the purpose of this specification, no distinction is made between the wheel brakes 102.

[0013] Also for purposes of description, it is assumed that a deceleration signal transmitter (schematically shown at 104) is configured to provide a braking signal corresponding to a desired braking action of a vehicle operator in a wired or wireless manner. The deceleration signal transmitter 104 may include, but is not limited to, a brake pedal, an autonomous braking controller, and / or any other suitable scheme for generating a braking signal according to which the braking system 100 may be actuated.

[0014] Braking system 100 also includes a fluid reservoir 106. Reservoir 106 stores and holds hydraulic fluid for use with braking system 100. The fluid within reservoir 106 is preferably maintained at or about atmospheric pressure, but the fluid may be stored at other pressures if desired. Figure 1 to Figure 2 is schematically shown as having two tanks or sections, in Figure 3106 to which fluid lines are connected. The sections may be separated by several internal walls within the reservoir 106 and provided to prevent complete discharge of the reservoir 106 in the event that one of the sections is exhausted due to a leak through one of the three lines connected to the reservoir 106. Alternatively, the reservoir 106 may include a plurality of separate housings. The reservoir 106 may include at least one liquid level sensor 108 ( Figure 3 Two are shown in the figure for redundancy) for detecting the liquid level of one or more portions of the reservoir 106.

[0015] The motor-driven master cylinder ("MC") 110 (which may be a dual-chamber type master cylinder 110, also referred to as a tandem power transfer unit) of each brake system 100 is used as a pressure source to provide a desired pressure level to the hydraulically operated wheel brakes 102 during a typical or normal non-failure braking application. An example of a suitable MC 110 arrangement is disclosed in co-pending U.S. Patent Application No. 17 / 708,070, filed on March 30, 2002, and entitled "Tandem Power Transfer Unit and Braking System Using the Same" (Attorney Docket No. 211835-US-NP), the entire contents of which are incorporated herein by reference for all purposes. The master cylinder 110 is operable to generate brake actuation pressures at first MC outputs 114 and second MC outputs 116, respectively, for hydraulically actuating the first pair of wheel brakes 102 and the second pair of wheel brakes 102 during a normal non-failure braking mode by actuation of the motor 112 of the master cylinder 110.

[0016] After the brakes are applied, fluid from the wheel brakes 102 may be returned to the master cylinder 110 and / or diverted to the reservoir 106. It is also contemplated that other configurations (not shown) of the brake system 100 may include hydraulic control of only selected one or more wheel brakes (the other wheel brakes being electrically controlled / electrically actuated). In the following aspects of the present invention, one of ordinary skill in the art will be able to readily provide such an arrangement for the desired use environment.

[0017] An isolation / pressure reducing control valve arrangement is associated with each wheel brake 102 of the plurality of wheel brakes 102. Each isolation / pressure reducing control valve arrangement includes an isolation valve 118 and a pressure reducing valve 120 for providing a required fluid route to the associated wheel brake 102. The reservoir 106 is, for example, connected to the return line 136 ( Figure 1 and Figure 2 Two are shown in Figure 3106 ) is hydraulically connected to the master cylinder 110 and each isolation / decompression control valve device. Each isolation / decompression control valve device includes a respective isolation valve 118 and a pressure reducing valve 120 arranged in series. For the corresponding wheel brake 102, the normally open isolation valve 118 of each isolation / decompression control valve device is hydraulically located between the corresponding wheel brake 102 and the master cylinder 110, and the normally closed pressure reducing valve 120 of each isolation / decompression control valve device is hydraulically located between the corresponding wheel brake 102 and the reservoir 106.

[0018] The isolation / relief control valve arrangement may selectively provide slip control to at least one wheel brake 102 driven by a master cylinder 110 and / or a pump / motor unit described below. More generally, the isolation / relief control valve arrangement and / or other valves of the braking system 100 (any of which may be solenoid operated and of any suitable configuration) may be used to help provide controlled braking operations such as, but not limited to, ABS, traction control, vehicle stability control, dynamic rear ratio adjustment, regenerative brake blending, and autonomous braking.

[0019] The first traction control isolation valve 122 is hydraulically interposed between the master cylinder 110 and the at least one isolation / decompression control valve arrangement via the first MC outlet 114. The second traction control isolation valve 124 is hydraulically interposed between the master cylinder 110 and the at least one isolation / decompression control valve arrangement via the second MC outlet 116. As shown, it is contemplated that an isolation / decompression control valve arrangement may be associated with each wheel brake 102 of the first pair of wheel brakes and the second pair of wheel brakes. The first traction control isolation valve 122 is hydraulically interposed between the motor-driven master cylinder 110 and the isolation / decompression control valve arrangement of the first pair of wheel brakes 102. Similarly, the second traction control isolation valve 124 is hydraulically interposed between the motor-driven master cylinder 110 and the isolation / decompression control valve arrangement of the second pair of wheel brakes 102.

[0020] The pump piston 126 is associated with at least one wheel brake 102 of the plurality of wheel brakes 102. The pump piston 126 is driven by a second electric motor 128 (different from the electric motor 112 included in the master cylinder 110), which transmits a rotational motion to each pump piston 126 to selectively provide pressurized hydraulic fluid to the isolation / relief control valve device of at least one wheel brake 102 associated with the pump piston 126. In the drawings, one pump piston 126 is associated with two wheel brakes 102, for a total of two pump pistons 126 in the brake system 100. The pump piston 126 and the second electric motor 128 together can be considered to constitute a secondary power transmission unit of the brake system 100. For example, the two pump pistons 126 shown in the figure can provide pressurized hydraulic fluid to the corresponding wheel brakes 102 via the first PTU output 130 and the second PTU output 132 respectively via the corresponding isolation / relief control valve device to actuate the first pair of wheel brakes 102 and the second pair of wheel brakes 102 in at least one of the normal non-fault braking mode and the backup braking mode. It is contemplated that in some configurations of the braking system 100, multiple pump pistons 126 can be associated with each of the first PTU output 130 and the second PTU output 132.

[0021] The secondary power transfer units (AKA "secondary brake modules") of the brake system 100 serve as a pressure source to provide desired pressure levels to selected wheel brakes 102 in a backup or "failure" situation (when, for some reason, the master cylinder 110 is unable to provide fluid to those selected wheel brakes 102). Thus, each secondary power transfer unit is directly fluidly connected to the reservoir for exchanging hydraulic fluid between these components without having to direct the fluid through the (potentially failed) motor-driven master cylinder 110 or another structure of the brake system 100.

[0022] The secondary power transfer unit may be used to selectively provide hydraulic fluid to at least one of the wheel brakes 102 in a backup braking mode, but may also selectively provide hydraulic fluid to at least one of the wheel brakes 102 in an enhanced braking mode, which may occur independently and / or simultaneously with the backup braking mode or the normal, non-fault braking mode. Examples of suitable enhanced braking mode functions that may be used for the braking system 100 include, but are not limited to, "overboost" (wherein a higher pressure is provided to a particular brake than is normally available from the master cylinder 110 alone) and "capacity increase" (wherein more fluid is provided to a particular brake than is normally available from the master cylinder 110). In some use environments, these enhanced braking modes may be facilitated by fluid communication from the respective first MC output 114 or second MC output 116 to a pump input of at least one pump piston 126 so as to selectively supply pressurized hydraulic fluid to the pump piston 126. For example, in at least one of the normal non-fault braking mode and the backup braking mode, the secondary power transfer unit may then supply hydraulic fluid at a boost pressure (higher than the pressure obtained from the master cylinder 110 ) to at least one of the first PTU output 130 and the second PTU output 132 .

[0023] It can be seen that each isolation / pressure reducing control valve device in the braking system 100 shown in the figure is in direct or indirect fluid communication with a selected one of the first MC output terminal 114 and the second MC output terminal 116 and a selected one of the first output terminal 130 and the second PTU output terminal 132, for selectively receiving pressurized fluid therefrom, for example, during different braking modes or as needed. A person skilled in the art will be able to easily configure the braking system 100 for any specific purpose application as needed.

[0024] Figures 1 to 3The brake system 100 shown in the figure also includes at least one electronic control unit ("ECU") 134 for controlling at least one of the master cylinder 110 and the auxiliary power transfer unit (via the second motor 128) in response to at least one brake pressure signal, wherein a first ECU 134A and a second ECU 134B are shown and described herein. The ECUs 134A, 134B may include a microprocessor and other circuits. The ECUs 134A, 134B receive various signals, process the signals, and control the operation of various electrical components of the corresponding brake system 100 in a wired and / or wireless manner in response to the received signals. The ECUs 134A, 134B may be connected to various sensors, such as a reservoir fluid level sensor 108, a pressure sensor, a travel sensor, a switch, a wheel speed sensor, and a steering angle sensor. The ECUs 134A, 134B may also be connected to an external module (not shown) for receiving information related to the vehicle's yaw rate, lateral acceleration, longitudinal acceleration, or other characteristics of vehicle operation for any reason, such as, but not limited to, controlling the brake system 100 during vehicle braking, stability operation, or other operating modes. Additionally, the ECUs 134A, 134B may be connected to an instrument cluster for collecting and providing information related to warning indicators, such as an ABS warning light, a brake fluid level warning light, and a traction control / vehicle stability control indicator light. It is contemplated that at least one of the ECUs 134A and 134B may be integrated into the master cylinder 110 or the second electric motor 128, for example.

[0025] The first ECU 134A and the second ECU 134B may divide the control tasks for the brake system 100 in any desired manner and may be easily configured by a person of ordinary skill in the art for a particular use environment of the brake system, but it is contemplated that any control tasks performed by one or more ECUs 134 will be completed in response to at least one brake pressure signal and / or brake signal generated by the deceleration signal transmitter 104. For example, the first ECU 134A may be operable to control the motor 112 of the master cylinder 110. The second ECU 134B may be operable to control the second motor 128, at least one isolation / decompression control valve device, and at least one first traction control isolation valve 122 and second traction control isolation valve 124. An example of a suitable ECU 134 device is disclosed in co-pending U.S. patent application No. 17 / 708,019, filed on March 30, 2022, entitled “CONTROL DEVICE FOR A BRAKING SYSTEM” (Agent Docket No. 211652-US-NP-2, hereinafter referred to as the “backup ECU”), the entire contents of which are incorporated herein by reference for all purposes.

[0026] A "brake pressure signal" is referred to above as at least one input that the ECU 134 may consider and responsively control one or more other components of the braking system 100 to achieve the desired braking result for a particular use environment. One potential source of a brake pressure signal is a brake pressure sensor. For example, as shown, the braking system 100 may include at least one (e.g., at least two) brake pressure sensors 138 (four are shown), each brake pressure sensor 138 being positioned directly hydraulically adjacent to a corresponding wheel brake 102 for sensing the fluid pressure at the corresponding wheel brake 102 and responsively generating a brake pressure signal. In other words, in Figures 1 to 3 In the illustrated braking system 100 , no other components are hydraulically interposed between the brake pressure sensors 138 and their corresponding wheel brakes 102 , such that the brake pressure signal generated by each brake pressure sensor 138 is related to the brake pressure actually sensed at the corresponding wheel brake 102 . Figures 1 to 3 In the illustrated braking system 100, each brake pressure sensor is hydraulically positioned between an isolation / reducing control valve arrangement and a corresponding wheel brake 102. This "on-brake" location (regardless of the actual physical location of the brake pressure sensor 138) may be helpful, for example, if the ECU 134 relies on knowing the actual sensed brake pressure at the corresponding wheel brake 102 when responsively controlling the master cylinder 110, the secondary power transfer unit, any valve of the braking system 100, or any other component for achieving a desired braking result.

[0027] For example, some vehicle manufacturers may wish to manage a brake control algorithm that simply provides brake pressure commands to the brake system from a vehicle-wide control system, rather than relying on calculations by the internal ECU 134. The use of a brake sensor 138 as shown in the figures and described herein may allow actual knowledge of brake pressure to be provided to the vehicle-wide control system for managing such a brake control algorithm, rather than relying on estimates available to the brake system during slip control.

[0028] As mentioned earlier, Figures 1 to 3 All of the brake systems 100 include many common features and structures, and where portions of the brake systems 100 shown are different, a person of ordinary skill in the art will readily be able to construct a suitable brake system in any desired combination and for any particular use environment using any desired configuration options shown in the drawings and / or described herein. With this in mind, several example features / arrangements of the various brake systems 100 will be discussed below.

[0029] like Figure 1 and Figure 3As shown in the brake system 100 of FIG. 1 , the reservoir 106 and the motor-driven master cylinder 110 may be co-located in a first housing (schematically indicated by a dashed line “1” in these figures), and the auxiliary power transfer unit may be located in a second housing spaced apart from the first housing (schematically indicated by a dashed line “2” in these figures). Optionally, as Figure 1 and Figure 3 As shown, the isolation / depressurization control valve arrangement and / or the first traction control isolation valve 122 and the second traction control isolation valve 124 may also be located in the second housing.

[0030] On the contrary, if Figure 2 As shown in the brake system 100 of FIG. 1 , the reservoir 106 and the auxiliary power transfer unit may be co-located in a first housing (schematically indicated by a dashed line “1” in these figures), and the motor-driven master cylinder 100 may be located in a second housing spaced apart from the first housing (schematically indicated by a dashed line “2” in these figures). Optionally, and also as Figure 2 As shown, the isolation / depressurization control valve arrangement and / or the first traction control isolation valve 122 and the second traction control isolation valve 124 may also be located in the first housing.

[0031] The first and second housings of any braking system 100 (and included / co-located components) may be provided and positioned for a particular use application by one of ordinary skill in the art based on factors including, but not limited to, achieving a desired result in at least one of vehicle design, manufacture, repair, space utilization, cost, size, regulatory compliance, etc.

[0032] Finally, in Figure 1 to Figure 2 In the illustrated brake system 100, each pump piston 126 is capable of directing fluid directly to and from the reservoir 106 via the pair of return lines 136 as needed. Figure 3 In the illustrated brake system 100, a single return line 136 provides a direct hydraulic connection between the reservoir 106 and each pump piston 126 (i.e., all pump pistons 126 of the brake system 100). Figure 3 In the illustrated brake system 100, the reservoir 106 includes a first reservoir fluid sensor 108 and a second reservoir fluid sensor 108, each of which is in electronic communication with a corresponding first electronic control unit 134A and a second electronic control unit 134B. As a result, even if one of the ECUs 134A, 134B is unavailable for the brake system 100 for some reason, the fluid level in the reservoir 106 can be monitored and adjusted by controlling the motor 112 or the second motor 128, depending on which of the ECUs 134A, 134B is still available in the brake system 100 at that time.

[0033] It is contemplated that a person skilled in the art may provide various other components, such as service and / or parking brake motors, in any brake system described herein to achieve a desired configuration for a particular use environment. For example, although a plurality of filters and pressure sensors are shown in the accompanying drawings, a detailed description thereof is omitted herein for the sake of brevity, as a person skilled in the art will readily understand how to provide the desired number, arrangement and / or operation of filters, sensors and any other components according to the needs of the particular use environment of the present invention.

[0034] As used herein, the singular forms "a", "an", and "the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include" and / or "comprise" used herein may specify the presence of the features, steps, operations, elements, and / or components, but do not exclude the presence or addition of other features, steps, operations, elements, components, and / or combinations thereof.

[0035] As used herein, the term "and / or" may include any and all combinations of one or more of the associated listed items.

[0036] It should be understood that when an element is referred to as being "on another element," "attached to another element," "connected to another element," "coupled with another element," "contacting another element," "adjacent to another element," etc., the element may be directly on, attached to, connected to, coupled with, contacting, or adjacent to another element, or there may be intervening elements. Conversely, when an element is referred to as being, for example, "directly on another element," "directly attached to another element," "directly connected to another element," "directly coupled with another element," "directly contacting another element," or "directly adjacent to another element," there are no intervening elements. One of ordinary skill in the art will also understand that a reference to a structure or feature disposed "directly adjacent to" another feature may have a portion overlapping the adjacent feature or a portion located below the adjacent feature, while a structure or feature disposed "adjacent to" another feature may not have a portion overlapping the adjacent feature or a portion located below the adjacent feature.

[0037] Spatially relative terms, such as "under," "beneath," "lower," "above," "upper," "proximal," "distal," and the like, may be used herein to facilitate description of the relationship of one element or feature to another element or feature as shown in the figures. It should be understood that the spatially relative terms may include different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is inverted, elements described as "under" or "beneath" other elements or features would be oriented "above" the other elements or features.

[0038] As used herein, the phrase "at least one of X and Y" may be interpreted to include: X; Y; or a combination of X and Y. For example, if an element is described as having at least one of X and Y, the element may include X; Y; or a combination of X and Y at a particular time, the selection of which may change over time. Conversely, the phrase "at least one of X" may be interpreted to include one or more X.

[0039] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the "first" element discussed below may also be referred to as the "second" element. The order of operations (or steps) is not limited to the order given in the claims or drawings unless otherwise specifically noted.

[0040] Although aspects of the present disclosure have been specifically shown and described with reference to the exemplary aspects above, it will be understood by those skilled in the art that various additional aspects can be envisioned. For example, the specific methods of using the above-mentioned devices are merely illustrative; those skilled in the art can easily determine any number of tools, sequence of steps, or other ways / options for placing the above-mentioned devices or their components in positions substantially similar to those shown and described herein. In order to maintain clarity in the drawings, certain repeated components are not specifically numbered, but those skilled in the art will recognize the element numbers that should be associated with the unnumbered components based on the numbered components; the presence or absence of element numbers in the drawings does not intend or imply a distinction between similar components. Any of the described structures and components can be integrally formed as a single whole or single piece, or composed of separate sub-components, wherein any of these constructions includes any suitable raw materials or custom components and / or any suitable material or combination of materials. Any of the described structures and components can be disposable or reusable as required by the specific use environment. Any component may have a user-perceivable mark to indicate the material, configuration, at least one dimension, etc. associated with the component, the user-perceivable mark potentially helping the user select a component from an array of similar components for a specific use environment. The "predetermined" state can be determined at any time before the structure being manipulated actually reaches the state, and the "predetermining" is performed shortly before the structure reaches the predetermined state. The term "substantially" is used herein to indicate a specified quality to a large extent (but not necessarily all)-the "substantially" quality allows for the possibility of some relatively small inclusion of non-quality items. Although certain components described herein are shown as having specific geometric shapes, all structures of the present disclosure may have any suitable shape, size, configuration, relative relationship, cross-sectional area or any other physical characteristics desired for a particular application. Any structure or feature described with reference to one aspect or configuration may be provided to any other aspect or configuration alone or in combination with other structures or features, because it would be impractical to describe each aspect and configuration discussed herein as having all the options discussed with respect to all other aspects and configurations. A device or method incorporating any of these features should be understood to fall within the scope of the present disclosure determined based on the following claims and any equivalents thereof.

[0041] Other aspects, objects and advantages can be obtained from a study of the drawings, the disclosure and the appended claims.

[0042] Related Applications

[0043] This application is related to the technology disclosed in one or more of the following: U.S. Provisional Patent Application (Application Number Pending) (Attorney Docket No. 300063-US-PSP [3]), which is filed concurrently with the present application and is entitled “PUSH THRUSCA"; U.S. Patent Application No. 18 / 447,490 (Attorney Docket No. 300080-US-NP), which is filed concurrently with the present application and is entitled "Braking System with Master Cylinder and Single Angle Actuator"; U.S. Patent Application No. 18 / 447,541 (Attorney Docket No. 300100-US-NP), which is filed concurrently with the present application and is entitled "Braking System with Motor-Driven Master Cylinder and Electric Auxiliary Power Transfer Unit"; U.S. Patent Application No. 18 / 447,609 (Attorney Docket No. 300642-US-NP), which is filed concurrently with the present application and is entitled "Vent Valve and Braking System Using the Vent Valve"; and U.S. Patent Application (Application Number Pending) (Attorney Docket No. 301149-US-NP), which is filed concurrently with the present application and is entitled "Bleed Valve and Braking System Using the Bleed Valve". The entire contents of all of these applications are incorporated herein by reference.

Claims

1. A braking system for actuating a plurality of wheel brakes including a first pair of wheel brakes and a second pair of wheel brakes, the braking system comprising: Storage; a motor-driven master cylinder operable during a normal, non-fault braking mode by actuation of an electric motor of said master cylinder to generate brake actuation pressures at a first master cylinder output and a second master cylinder output for hydraulically actuating said first pair of wheel brakes and said second pair of wheel brakes, respectively; a secondary power transfer unit configured to selectively provide pressurized hydraulic fluid at a first power transfer unit output and a second power transfer unit output for actuating the first pair of wheel brakes and the second pair of wheel brakes in at least one of a normal non-failure braking mode and a backup braking mode, the secondary power transfer unit including a power transfer unit motor configured to selectively pressurize the hydraulic fluid by transmitting rotational motion to at least two pump pistons, each pump piston providing pressurized hydraulic fluid to a corresponding one of the first power transfer unit output and the second power transfer unit output, each of the first power transfer unit output and the second power transfer unit output providing fluid to a corresponding pair of wheel brakes of the first pair of wheel brakes and the second pair of wheel brakes; at least two brake pressure sensors, each brake pressure sensor being positioned directly adjacent to a corresponding wheel brake for sensing hydraulic pressure at the corresponding wheel brake and responsively generating a brake pressure signal; as well as an electronic control unit that controls at least one of the auxiliary power transfer unit and the master cylinder in response to at least one brake pressure signal; and Wherein, the secondary power transfer unit is directly fluidically connected to the reservoir.

2. The brake system according to claim 1, comprising an isolation / pressure reducing control valve device associated with each wheel brake of the plurality of wheel brakes, each isolation / pressure reducing control valve device being controlled by the electronic control unit.

3. The braking system according to claim 2, wherein: Each isolation / reducing control valve device is in fluid communication with both a selected one of the first and second master cylinder outputs and a selected one of the first and second power transfer unit outputs for selectively receiving pressurized hydraulic fluid therefrom.

4. The braking system according to claim 2, wherein: Each brake pressure sensor is hydraulically interposed between the isolation / reducing control valve device and a corresponding wheel brake.

5. The braking system according to claim 1, wherein: The motor-driven master cylinder is a dual-chamber master cylinder.

6. The braking system according to claim 1, wherein: The secondary power transfer unit includes a plurality of pump pistons associated with each of the first power transfer unit output and the second power transfer unit output.

7. The braking system according to claim 1, comprising: a first traction control isolation valve hydraulically interposed between the motor-driven master cylinder and the first pair of wheel brakes via the first master cylinder outlet; as well as A second traction control isolation valve is hydraulically interposed between the motor-driven master cylinder and the second pair of wheel brakes via the second master cylinder outlet.

8. The braking system of claim 7, comprising an isolation / relief control valve arrangement associated with each of the first pair of wheel brakes and the second pair of wheel brakes, wherein: The first traction control isolation valve is hydraulically interposed between the motor-driven master cylinder and the isolation / decompression control valve arrangement of the first pair of wheel brakes, and wherein the second traction control isolation valve is hydraulically interposed between the motor-driven master cylinder and the isolation / decompression control valve arrangement of the second pair of wheel brakes.

9. The braking system according to claim 8, wherein: Each brake pressure sensor is hydraulically interposed between the isolation / reducing control valve device and a corresponding wheel brake.

10. The brake system according to claim 1, wherein: The electronic control unit is a first electronic control unit that controls the motor-driven master cylinder, and the braking system includes a second electronic control unit that controls the auxiliary power transfer unit, wherein both the first electronic control unit and the second electronic control unit respond to at least one brake pressure signal to respectively control the motor-driven master cylinder and the auxiliary power transfer unit.

11. The braking system of claim 8, comprising an isolation / relief control valve arrangement associated with each of the first pair of wheel brakes and the second pair of wheel brakes, wherein: The first electronic control unit controls each of the isolation / pressure reducing control valve devices.

12. The braking system according to claim 10, comprising: a first traction control isolation valve hydraulically interposed between the motor-driven master cylinder and the first pair of wheel brakes via the first master cylinder outlet; as well as a second traction control isolation valve hydraulically interposed between the motor-driven master cylinder and the second pair of wheel brakes via the second master cylinder outlet; The second electronic control unit controls the first traction control isolation valve and the second traction control isolation valve.

13. The braking system of claim 1, comprising a deceleration signal transmitter configured to provide a braking signal corresponding to a desired braking action of an operator of the vehicle in a wired or wireless manner, wherein: The electronic control unit controls at least one of the auxiliary power transfer unit and the motor-driven master cylinder in response to the brake signal.

14. The brake system according to claim 1, wherein: Each of the first master cylinder output end and the second master cylinder output end is fluidically connected to the pump input end of at least one pump piston for selectively supplying pressurized hydraulic fluid to the at least one pump piston. In at least one braking mode of a normal non-fault braking mode and a backup braking mode, the auxiliary power transfer unit selectively boosts the pressure of the pressurized hydraulic fluid to supply hydraulic fluid with boosted pressure to at least one of the first power transfer unit output end and the second power transfer unit output end.

15. The brake system according to claim 1, wherein: The reservoir and the motor-driven master cylinder are co-located in a first housing, and the secondary power transfer unit is located in a second housing spaced apart from the first housing.

16. The brake system of claim 1, comprising an isolation / pressure reducing control valve device associated with each of the plurality of wheel brakes, each isolation / pressure reducing control valve device being controlled by the electronic control unit; and in, The reservoir and the motor-driven master cylinder are co-located in a first housing, and the secondary power transfer unit and the isolation / decompression control valve device are located in a second housing spaced apart from the first housing.

17. The braking system according to claim 16, wherein: Each brake pressure sensor is hydraulically interposed between the isolation / reducing control valve device and a corresponding wheel brake.

18. The brake system according to claim 1, wherein: The reservoir and the secondary power transfer unit are co-located in a first housing, and the motor-driven master cylinder is located in a second housing spaced apart from the first housing.

19. The brake system of claim 1, comprising an isolation / pressure reducing control valve device associated with each of the plurality of wheel brakes, each isolation / pressure reducing control valve device being controlled by the electronic control unit; and in, The reservoir and the secondary power transfer unit are co-located in a first housing, and the motor-driven master cylinder is located in a second housing spaced apart from the first housing.

20. The braking system according to claim 19, wherein: Each brake pressure sensor is hydraulically interposed between the isolation / reducing control valve device and a corresponding wheel brake.

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