Brake system with motor-driven master cylinder and pump inlet attenuator

Abstract

The invention relates to a brake system with an electric motor driven master cylinder and a pump inlet attenuator. The brake system includes a master cylinder that generates pressure at first and second master cylinder outputs for actuating a first pair of wheel brakes and a second pair of wheel brakes. The secondary brake module is configured to provide fluid at the first power transmission unit output and the second power transmission unit output for actuating wheel brakes. The secondary brake module includes an electric motor configured to selectively pressurize hydraulic fluid by transmitting rotational motion to the at least two pump pistons. A pump inlet attenuator is hydraulically disposed between the reservoir and the pump piston and is in direct fluid connection with the reservoir via a single return line. The electronic control unit controls at least one of the secondary brake module and the master cylinder in response to a brake pressure signal. The pump inlet attenuator regulates the pressure in a single return line to reduce pressure fluctuations at the inlet side of each pump piston only by mechanical pressure attenuation.

Description

Technical Field

[0001] The present disclosure relates to an apparatus and method for using a brake system having a motor-driven master cylinder and a pump inlet attenuator, and more particularly to a method and apparatus for a brake system having a motor-driven master cylinder, a pump inlet attenuator, and a bypass valve. 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 the 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 an anti-lock control and a traction slip control, which may 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 by Blaise Ganzel on October 1, 2020, and entitled “Braking System with Multiple Pressure Sources,” and U.S. Patent Application Publication No. 2023 / 0048447, published by Blaise Ganzel on February 16, 2023, and entitled “Apparatus and Method for Controlling a Hydraulic Braking System Including Manual Advancement,” 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 is described for actuating a plurality of wheel brakes including a first pair of wheel brakes and a second pair of wheel brakes. The braking system includes a reservoir and a motor-driven master cylinder, which can be operated to generate brake actuation pressure at a first master cylinder output and a second master cylinder 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 auxiliary brake module is 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-fault braking mode and a backup braking mode. The auxiliary brake module includes a power transfer unit motor, which is 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 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 provides fluid to a corresponding pair of wheel brakes in the first pair of wheel brakes and the second pair of wheel brakes. A single return line puts the reservoir and each pump piston in hydraulic connection. A pump inlet attenuator is hydraulically disposed between the reservoir and the pump piston and is directly fluidically connected to the reservoir via a single return line. An electronic control unit is provided for controlling at least one of the secondary brake module and the master cylinder in response to at least one brake pressure signal. The pump inlet attenuator regulates the pressure in the single return line to reduce pressure fluctuations at the inlet side of each pump piston by mechanical pressure attenuation alone. 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 2A is in the first configuration Figure 1 A schematic cross-sectional view of components of a braking system;

[0008] Figure 2B It is in the second configuration Figure 2A A schematic cross-sectional view of a component of;

[0009] Figure 3 yes Figure 1 A schematic cross-sectional view of components of a braking system;

[0010] Figure 4 is along Figure 3A cross-sectional view taken along line “4-4”;

[0011] Figure 5 is a schematic hydraulic diagram of an exemplary brake system according to another aspect of the present invention; and

[0012] Figure 6 is used for Figure 1 and Figure 5 Schematic side view of an exemplary arrangement of components of any brake system. DETAILED DESCRIPTION

[0013] 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.

[0014] The present invention comprises, consists of, or consists essentially of any combination of the following features.

[0015] Figure 1 An exemplary braking system 100 for actuating a plurality of wheel brakes 102 is schematically shown. The braking system 100 is shown here as a hydraulic braking system in which fluid pressure is used to apply a braking force to the braking system 100. The braking system 100 may 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 may be provided with other braking functions, such as anti-lock braking (ABS) and other skid control features to effectively brake the vehicle. The components of the braking system 100 may be housed in one or more blocks or housings. The blocks or housings may be made of a solid material (e.g., aluminum) that has been drilled, machined, or otherwise shaped to accommodate the various components. Fluid conduits may also be formed in the blocks or housings.

[0016] exist Figure 1In the illustrated embodiment of the braking system 100, 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 front wheels and rear wheels of the vehicle on which the corresponding braking system 100 is installed. For example, the braking systems 100 may each 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 arrangement for a particular use environment, for the purposes of this specification, no distinction is made herein between the structures of the various wheel brakes 102. The wheel brakes 102 are described herein as including a first pair of wheel brakes 102 and a second pair of wheel brakes 102, wherein the first pair of wheel brakes 102 and the second pair of wheel brakes 102 are characterized by RF / LR and LF / RR, such as Figure 1 However, the brake system 100 may also or alternatively be assigned LF / LR and RF / RR or RF / LF and RR / LR pairs as desired.

[0017] 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 from which the braking system 100 can be actuated.

[0018] 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 1 106 is schematically shown as having three tanks or sections to which fluid lines are connected. The sections may be separated by several inner 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 fluid level sensor 108 for detecting the fluid level of one or more sections of the reservoir 106.

[0019] The motor-driven master cylinder ("MC" or "[master] power transfer unit") 110 (which may be a dual-chamber type master cylinder 110, also referred to as a tandem power transfer unit) of each braking 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-fault 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, 2022, 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 a first MC output 114 and a second MC output 116 during a normal, non-fault braking mode by actuation of the motor 112 of the master cylinder 110 for hydraulically actuating the first pair of wheel brakes 102 and the second pair of wheel brakes 102, respectively.

[0020] After applying the brakes, 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 a selected one or more wheel brakes (the other wheel brakes being electronically controlled / actuated). Following aspects of the present invention, one of ordinary skill in the art will be readily able to provide such an arrangement for the desired use environment.

[0021] An isolation / dump control valve device is associated with each wheel brake 102 of the plurality of wheel brakes 102. Each isolation / dump control valve device includes an isolation valve 118 and a dump valve 120 for providing a desired fluid route to the associated wheel brake 102. The reservoir 106 is hydraulically connected to the master cylinder 110 and is hydraulically connected to each isolation / dump control valve device, for example, via a return line 136. Each isolation / dump control valve device includes a corresponding isolation valve 118 and a dump valve 120 arranged in series. The normally open isolation valve 118 of each isolation / dump control valve device is hydraulically located between the corresponding wheel brake 102 and the master cylinder 110, and the normally closed dump valve 120 of each isolation / dump control valve device is hydraulically located between the corresponding wheel brake 102 and the reservoir 106 for the corresponding wheel brake 102.

[0022] The isolation / dump control valve arrangement may selectively provide slip control to at least one wheel brake 102 powered by a master cylinder 110 and / or a secondary brake module described below. More generally, the isolation / dump 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.

[0023] The first traction control isolation valve 122 is hydraulically interposed between the master cylinder 110 and the at least one isolation / dump control valve arrangement via the first MC output 114. The second traction control isolation valve 124 is hydraulically interposed between the master cylinder 110 and the at least one isolation / dump control valve arrangement via the second MC output 116. As shown, it is contemplated that the isolation / dump control valve arrangement may be associated with each wheel brake 102 in 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 / dump 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 / dump control valve arrangement of the second pair of wheel brakes 102.

[0024] 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 power transfer unit (PTU) motor 128 (different from the motor 112 included in the master cylinder 110) that transmits rotational motion to each pump piston 126 to selectively provide pressurized hydraulic fluid to the isolation / dump control valve device of at least one wheel brake 102 associated with the pump piston 126. Figure 1One pump piston 126 is shown associated with two wheel brakes 102, for a total of two pump pistons 126 in the braking system 100. The pump piston 126 and the PTU motor 128 together can be considered to constitute a secondary brake module (also referred to as a "secondary power transfer unit") of the braking 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 corresponding isolation / dump control valve devices (when present) at the first PTU output end 130 and the second PTU output end 132, respectively, to actuate the first pair of wheel brakes 102 and the second pair of wheel brakes 102 in at least one of a normal non-fault braking mode and a backup braking mode. Each of the first PTU output end 130 and the second PTU output end 132 can provide fluid to a corresponding pair of wheel brakes in the first pair of wheel brakes 102 and the second pair of wheel brakes 102. It is contemplated that in some configurations of the brake system 100 , a plurality of pump pistons 126 may be associated with each of the first PTU output 130 and the second PTU output 132 .

[0025] The slave brake modules of the brake system 100 serve as a pressure source to provide a desired pressure level to those selected wheel brakes 102 in a backup or "failure" situation (when, for some reason, the master cylinder 110 is unable to provide fluid to the selected wheel brakes 102). Thus, each slave brake module is directly fluidly connected to the reservoir 106 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.

[0026] The secondary brake module can be used to selectively provide hydraulic fluid to at least one wheel brake 102 not only in a backup braking mode but also in an enhanced braking mode, which can 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 can be used for the brake system 100 include, but are not limited to, "overboost" (wherein a higher pressure is provided to a specific brake than is normally available from the master cylinder 110 alone) and "capacity increase" (wherein more fluid is provided to a specific brake than is normally available from the master cylinder 110). In some use environments, these enhanced braking modes can be facilitated by fluid communication from the corresponding first MC output 114 or second MC output 116 to the pump input of at least one pump piston 126 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 brake module can then supply hydraulic fluid at a boost pressure (higher than the pressure available from the master cylinder 110) to at least one of the first PTU output 130 and the second PTU output 132.

[0027] It can be seen that each isolation / dump control valve device in the brake system 100 shown in the figure is in direct or indirect fluid communication with a selected one of the first MC output port 114 and the second MC output port 116 and a selected one of the first PTU output port 130 and the second PTU output port 132 for selectively receiving pressurized fluid from these output ports, for example, during different braking modes or as needed. A person of ordinary skill in the art will be able to readily configure the brake system 100 for any particular purpose application as needed.

[0028] Figure 1 The illustrated braking system 100 also includes at least one electronic control unit ("ECU") 134 for controlling at least one of the master cylinder 110 and the secondary brake module (via the PTU 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 braking system 100 in response to the received signals in a wired and / or wireless manner. 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, for example, with the master cylinder 110 or the PTU motor 128.

[0029] 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 accomplished 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 PTU motor 128, at least one of the isolation / dump control valve devices, and at least one of the first traction control isolation valve 122 and the second traction control isolation valve 124.

[0030] A "brake pressure signal" is referred to hereinabove as at least one input that the ECU 134 may consider and responsively control one or more other components of the brake system 100 to achieve a 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 brake system 100 may include at least one (e.g., at least two) brake pressure sensors 138. Figure 1 As can be seen in the figure, the first brake pressure sensor 138A can be hydraulically disposed between the first traction control isolation valve 122 and the master cylinder 110, and the second brake pressure sensor 138B can be hydraulically disposed between the second traction control isolation valve 124 and the master cylinder 110. One of ordinary skill in the art can readily provide the desired number / location / type of pressure sensors 138 for a particular brake system 100.

[0031] The first bypass isolation valve 140 is hydraulically disposed between the first traction control isolation valve 122 and the front brakes of the first pair of wheel brakes 102, and is connected in parallel with the isolation / dump control valve arrangement corresponding to the front brakes of the first pair of wheel brakes 102. The second bypass isolation valve 142 is hydraulically disposed between the second traction control isolation valve 124 and the front brakes of the second pair of wheel brakes 102, and is connected in parallel with the isolation / dump control valve arrangement corresponding to the front brakes of the second pair of wheel brakes 102. Figure 1 The illustrated first bypass isolation valve 140 and second bypass isolation valve 142 are shown as normally open isolation valves.

[0032] The first bypass isolation valve 140 and the second bypass isolation valve 142 are configured to close in response to a higher hydraulic fluid pressure on the upstream side (i.e., the side closer to the master cylinder 110) of the respective bypass isolation valves 140 and 142 so that the brake system 100 maintains the first bypass isolation valve 140 and the second bypass isolation valve 142 closed while the current draw on the system is relatively low. The first bypass isolation valve 140 and the second bypass isolation valve 142 also have a larger orifice size than the orifice size of the isolation valve 118 of the corresponding isolation / dump control valve device and are oriented in the opposite direction of fluid flow to the isolation valve 118 of the corresponding isolation / dump control valve device (i.e., are plumb in the opposite direction of the corresponding isolation valve 118). Therefore, the first bypass isolation valve 140 and the second bypass isolation valve 142 can therefore help to quickly pressurize the wheel brakes 102 during a "spike apply" condition. (It should be noted that the first bypass isolation valve 140 and the second bypass isolation valve 142 may also have larger orifice sizes than the orifice sizes of the corresponding first traction control isolation valve 122 and the second traction control isolation valve 124.) An example of the use of the first bypass isolation valve 140 and the second bypass isolation valve 142 is that once the isolation valve 118 is closed, an undesirably large pressure spike may occur due to the motor 112 of the master cylinder 110 having inertia and taking a predetermined amount of time to stop rotating and stop driving the piston in the chamber of the master cylinder 110. The presence of the first bypass isolation valve 140 and the second bypass isolation valve 142 in handling the "spike application" situation also allows the use of a smaller corresponding isolation valve 118 because the motor 112 does not need to rotate quickly to achieve the desired amount of fluid pressure at the associated wheel brake 102. FIG. 2A to FIG. 2B The structure of the first bypass isolation valve 140 and the second bypass isolation valve 142 are discussed in more detail.

[0033] A brake motor 144 may be associated with each rear wheel brake in the front and rear pair of wheel brakes 102. When present, the brake motor 144 may be operated in at least a backup braking mode and, when multiple ECUs 134 are present, may be controlled by the ECU 134 opposite the motor 112 of the master cylinder 110 (in response to the brake signal). For example, when the first ECU 134A controls the motor 112 of the master cylinder 110, the second ECU 134B may control the PTU motor 128 and the brake motor 144 for redundancy in the braking system 100 in the event that the first ECU 134A fails.

[0034] exist Figure 1In the brake system 100 of FIG. 1 , a single return line 136 places the reservoir 106 and each pump piston 126 in hydraulic connection. The brake system 100 also includes a pump inlet attenuator 146 that is hydraulically interposed between the reservoir 106 and the pump piston 126 for “attenuating” the fluid flow therebetween. The pump inlet attenuator 146 is directly fluidly connected to the reservoir 106 via the single return line 136, and regulates the pressure in the single return line 136 to reduce pressure fluctuations on the inlet side of each pump piston 126 by mechanical pressure attenuation alone. At least a portion of the pump inlet attenuator 146 may be in fluid communication with an ambient space external to the brake system 100, as will be described below with reference to FIG. Figure 3 to Figure 4 The pump inlet attenuator 146 may be a single pump inlet attenuator 146 as shown and discussed herein, or it is contemplated that multiple pump inlet attenuators (not shown) may be provided for certain use environments of the brake system 100 .

[0035] Known brake systems require that the fluid column in the return line 136 be accelerated and decelerated due to flow fluctuations generated at the inlet of the pump piston 126. This results in undesirable pressure fluctuations and reduced pump volumetric efficiency. Conversely, the presence of the pump inlet attenuator 146 promotes improved pump build rate performance with a smaller diameter and / or longer return line 136. The pump inlet attenuator 146 (also referred to as a "pump inlet damper") can be packaged inline in the return line 136 (e.g., in a reservoir hose adapter of the brake system 100) or "piggybacked" in the housing structure of another component (e.g., a secondary brake module). Because the pump piston 126 of the brake system 100 pulls relatively low pressure fluid from the return line 136 (inline within which the pump inlet attenuator 146 is inline), the pump inlet attenuator 146 does not need to be able to withstand the relatively high pressure generated in the conduit originating from the main cylinder 110. Thus, the pump inlet attenuator 146 can service two / all pump pistons 126 simultaneously, yet still have relatively inexpensive (eg, molded plastic) components because the pump inlet attenuator 146 operates in a low pressure environment, as shown.

[0036] For simplicity, the following FIG. 2A to FIG. 2B The description pertains to the first bypass isolation valve 140 , but in many use environments, the second bypass isolation valve 142 will be similarly configured. Figure 2A The bypass isolation valves 140, 142 are shown in an open state and Figure 2B The middle bypass isolation valves 140, 142 are energized to close. FIG. 2A to FIG. 2B, the first bypass isolation valve 140 and the second bypass isolation valve 142 may each include an MC channel 246 in fluid communication with the corresponding first MC output end 114 or the second MC output end 116, a brake-side channel 248 in fluid communication with the corresponding front wheel brake 102, and a longitudinally extending bypass valve sleeve 250. The MC channel 246 may be in indirect fluid communication with the corresponding first MC output end 114 or the second MC output end 116 via the corresponding first traction control isolation valve 122 or the second traction control isolation valve 124. The brake-side channel 248 may be in direct fluid communication with the corresponding front wheel brake 102. For a specific use environment, a person of ordinary skill in the art may easily configure the brake system 100 including one or more bypass isolation valves 140 and 142.

[0037] The bypass valve body 252 has a first body end 254 and a second body end 256 spaced longitudinally apart, with a bypass body lumen 258 extending between the first body end 254 and the second body end 256. The bypass valve body 252 spaces at least a portion of the bypass valve sleeve 250 that at least partially surrounds the first body end 254 from at least the brake side passage 248 that is located adjacent to the second body end 256. A bypass armature 260 is located within the bypass valve sleeve 250 adjacent to the first body end 254. A bypass tappet 262 is at least partially surrounded by the bypass armature 260 and the bypass valve sleeve 250. The bypass tappet 262 extends at least partially through the bypass body lumen 258. The bypass tappet 262 is selectively longitudinally moved within the bypass body lumen 258 toward the bypass valve body 252 by energizing the bypass armature 260. A bypass biasing spring 264 is mechanically interposed between the bypass lifter 262 and at least a portion of the bypass valve body 252 within the bypass body lumen 258. The bypass biasing spring 264 operates to bias the bypass lifter 262 toward the first body end 254. The bypass valve seat 266 is carried by a bypass seat body 268 positioned immediately adjacent the second body end 256.

[0038] Any desired number of bypass valve filters 270 may be provided, and the bypass valve filters 270 are shown here as a belt filter 270A and a disc filter 270B associated with the MC channel 246 and the brake side channel 248, respectively. An air gap spacer 272 may be provided to help maintain tolerances and / or transfer forces between components as desired. The bypass isolation valve 140, 142 may be carried by a housing block 274 of the brake system 100, and at least a portion of the MC channel 246 and the brake side channel 248 may be formed within the housing block 274. The bypass valve body 252 or any other desired component of the bypass isolation valve 140, 142 may be maintained within the valve bore 276 of the housing block 274 by riveting, crimping, welding, soldering, adhesives, fasteners, or any other desired maintenance solution.

[0039] The bypass valve fluid path F extends (in a bidirectional manner) through a selected one of the MC passage 246 and the brake-side passage 248, through the bypass valve seat 266, through at least one laterally extending side hole 278 in the bypass valve body 252, through at least a portion of the bypass body lumen 258, and through the other of the MC passage 246 and the brake-side passage 248 to place the two passages in fluid communication. Figure 2A Normally Open position shown.

[0040] exist Figure 2B In the illustrated “energized closed” position, the bypass lifter 262 selectively engages the bypass valve seat 266 to substantially block the bypass valve fluid path F in response to energization of the bypass armature 260 to move the bypass lifter 262 toward the second body end 256 .

[0041] Figure 3 to Figure 4 The pump inlet attenuator 146 is shown. The pump inlet attenuator (PIA) piston 380 has a piston head 382 and a piston rod 384. The piston rod 384 has at least one rib 385 extending longitudinally thereof, as shown, and the plurality of ribs 385 together define the piston rod 384 having an at least partially cross-shaped cross-section to facilitate the flow of brake fluid within the pump inlet attenuator 146. The PIA piston 380 is hydraulically disposed between the pump piston 126 and an ambient space "A" external to the brake system 100.

[0042] The PIA piston chamber 386 circumferentially surrounds the piston head 382, ​​and the piston head 382 reciprocates longitudinally (i.e., parallel to the piston head 382) within the PIA piston chamber 386. Figure 3 394). The PIA seal 388 is laterally disposed between the piston head 382 and the inner wall 390 of the PIA piston chamber 386 to divide the PIA piston chamber 386 into a wet chamber portion 392 and a dry chamber portion 394 spaced apart longitudinally. The dry chamber portion 394 is a portion of the pump inlet attenuator 146 that is in fluid communication with the ambient space A outside the brake system 100. The PIA spring 396 biases the PIA piston 380 toward the dry chamber portion 394. At least one retainer 398 may be located on the outermost portion of the piston head 382 to prevent the surface of the piston head 382 from being in full contact with the solid retainer disk 400. Air may be exchanged between the ambient space A and the dry chamber portion 394 via the exhaust line 402. Conversely, it is contemplated that the retainer disk 400 may include one or more perforations, through holes, or be at least partially made of a breathable material (not shown) to allow air to be exchanged directly therethrough with the ambient space A without the need for an exhaust line 402.

[0043] The PIA piston 380 moves toward the pump piston (at Figure 1The PIA piston 380 moves longitudinally away from the pump piston 126 (i.e., toward the retainer disk 400) in response to one or more of the biasing force from the PIA spring 396, a second predetermined amount of negative pressure from the pump piston 126 (the second predetermined amount of negative pressure is less than the first predetermined amount of negative pressure), and a predetermined amount of positive pressure from the pump piston 126. Figure 3 As shown, the pump inlet attenuator 146 is shown having a "stub" type connector having a seal thereabout and which is inserted into the housing block 274 and is thus in fluid communication with the pump piston 126, but it is contemplated that any suitable arrangement and attachment scheme may be provided to connect the pump inlet attenuator 146 to the brake system 100 as desired. More generally, one of ordinary skill in the art may readily provide a suitable pump inlet attenuator 146 for a particular use application of the brake system 100.

[0044] See now Figure 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 secondary brake module may be located in a second housing spaced apart from the first housing (schematically indicated by a dashed line “2” in these figures). Figure 1 As shown, the isolation / dump control valve arrangement, the first and second bypass isolation valves 140 and 142 and / or the first and second traction control isolation valves 122 and 124 may also be located in the second housing.

[0045] The first housing and the second housing (and included / co-located components) of any braking system 100 can be provided and configured by a person of ordinary skill in the art for a specific use application based on factors including but not limited to achieving the desired results in at least one of design, manufacturing, maintenance, space utilization in the vehicle, cost, size, regulatory compliance, etc.

[0046] Figure 5 A second embodiment of a brake system 100 is shown. Figure 5 The braking system is similar to Figure 1 The braking system is therefore different from the reference Figure 1 Describe the same or similar structure Figure 5 For the second embodiment, the description of common elements and operations similar to those in the aforementioned first embodiment will not be repeated, but should be considered to be appropriately incorporated by reference below.

[0047] exist Figure 5In the brake system 100, each of the first bypass isolation valve 140' and the second bypass isolation valve 142' is the same isolation valve type as the isolation valve 118 of the corresponding isolation / dump control valve device (rather than Figure 1 The first embodiment of the brake system 100 shown in FIG. Figure 2A and Figure 2B Bypass isolation valves 140, 142). That is, Figure 5 In the second embodiment of the brake system 100 shown, each of the first bypass isolation valve 140' and the second bypass isolation valve 142' includes a check valve mechanism 504 that selectively allows fluid to flow therethrough. Each of the first bypass isolation valve 140' and the second bypass isolation valve 142' is configured to open in response to a higher hydraulic fluid pressure on the upstream side of the bypass isolation valve 140' and 142" (i.e., the side closer to the master cylinder 110), which in turn is related to the fact that the first bypass isolation valve 140' and the second bypass isolation valve 142' are each configured to open in response to a higher hydraulic fluid pressure on the upstream side of the bypass isolation valve 140' and 142" (i.e., the side closer to the master cylinder 110). Figure 1 The arrangement is the opposite. Figure 5 In the brake system 100 of the embodiment of the present invention, the orifices of the first bypass isolation valve 140' and the second bypass isolation valve 142' are larger than the corresponding orifices of the first bypass isolation valve 140 and the second bypass isolation valve 142 discussed above, at least in part because the first bypass isolation valve 140' and the second bypass isolation valve 142' are not used in Figure 4 The brake system 100 performs pressure control in the brake system 100, but remains closed only during slip control events. Figure 5 The brake system 100 shown may be Figure 1 The brake system is simpler in structure because Figure 5 The brake system includes a valve that is less than one to be provided and configured.

[0048] Figure 6 The physical arrangement of at least a portion of a brake system 100 is schematically shown, which brake system may be implemented as, for example Figure 1 and Figure 5 At least a portion of the first housing '1' of the first or second embodiment of the brake system 100 shown in . In any of these brake systems 100, the motor-driven master cylinder 110 includes a MC drive motor 112 (as previously described), a MC primary chamber 608, and a MC secondary chamber 610. The MC primary piston 612 is configured to selectively move longitudinally within the MC primary chamber 608 in response to longitudinal movement imposed by the ball nut assembly 614 along the ball nut axis "BNA". (The "longitudinal" direction is represented by Figure 6 ) The MC slave piston 616 is configured to selectively move longitudinally within at least one of the MC main chamber 608 and the MC slave chamber 610 in response to longitudinal movement imparted by the ball nut assembly 614 along the ball nut axis BNA.

[0049] The MC drive motor 112 rotates a drive shaft 618 having a drive shaft axis ("DSA") extending substantially parallel to the ball nut axis BNA. The rotational motion of the drive shaft 618 is transmitted to the rotational motion of the spindle 620 of the ball nut assembly 614 via the MC gear train 622. It is emphasized that in Figure 6 In the physical arrangement shown, rotational motion is transmitted by the MC drive motor 112 to the drive shaft 618, which is then transferred by the MC gear train 622 to the laterally spaced and substantially parallel spindles 620 to rotate the ball nut assembly 614 and accordingly drive the master cylinder 110. This "U-turn" of power from the MC drive motor 112 facilitates providing a compact package size and reduced footprint for the components included within the physical configuration of the brake system 100.

[0050] It is contemplated that a person of ordinary skill in the art may provide various other components, such as a service brake motor and / or a parking brake motor, 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 or other sensors are shown in the accompanying drawings, their specific description is omitted here for the sake of brevity, because a person of ordinary skill 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.

[0051] 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 one or more other features, steps, operations, elements, components and / or combinations thereof.

[0052] As used herein, the term "and / or" may include any and all combinations of one or more of the associated listed items.

[0053] 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," "in contact with another element," "adjacent to another element," etc., the element may be directly on, attached to, connected to, coupled with, in contact with, or adjacent to another element, or intervening elements may also be present. In contrast, 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," "directly in contact with," or "directly adjacent to" another element, there are no intervening elements. One of ordinary skill in the art will also understand that references to structures or features that are disposed "directly adjacent to" another feature may have portions that overlap or underlie the adjacent features, whereas structures or features that are disposed "adjacent to" another feature may not have portions that overlap or underlie the adjacent features.

[0054] Spatially relative terms, such as "under," "beneath," "lower," "above," "upper," "proximal," "distal," and the like, may be used herein to facilitate describing the relationship of one element or feature to another element or feature as shown in the figures. It should be understood that 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 figure is inverted, elements described as "under" or "beneath" other elements or features would be oriented "above" the other elements or features.

[0055] 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 Xs.

[0056] 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.

[0057] Although aspects of the present disclosure have been specifically shown and described with reference to the above exemplary aspects, 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 device described above are merely illustrative; a person skilled in the art can easily determine any number of tools, sequence of steps, or other ways / options for placing the above-mentioned device or its components in a position substantially similar to those shown and described herein. In order to maintain clarity in the drawings, certain repeated components are not specifically numbered, but a person 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 monolithic piece, or composed of separate subcomponents, any of which 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, depending on the needs of 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 property 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. Devices or methods that combine 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.

[0058] Other aspects, objects and advantages can be obtained from a study of the drawings, the disclosure and the appended claims.

[0059] Related Applications

[0060] This application claims priority to U.S. Provisional Patent Application No. 63 / 580,048 (Agent File No. 301647-US-PSP), filed on September 1, 2023, and entitled “Braking System with Motor Driven Master Cylinder and Pump Inlet Attenuator,” the entire contents of which are incorporated herein by reference for all purposes.

[0061] This application relates to technology disclosed in one or more of the following: U.S. Provisional Patent Application No. 63 / 580,042 (Agent Docket No. 301699-US-PSP), filed on September 1, 2023 and entitled “Braking System with Motor-Driven Master Cylinder and Low-Pressure Accumulator”; U.S. Patent Application No. 18 / 474,657 (Agent Docket No. 301158-US-NP), filed on September 26, 2023 and entitled “Braking System with Motor-Driven Master Cylinder and Bypass Valve”; and U.S. Patent Application No. 18 / 474,678 (Agent Docket No. 301699-US-NP), filed on September 26, 2023 and entitled “Braking System with Motor-Driven Master Cylinder and Low-Pressure Accumulator”; the entire contents of all of these applications are incorporated herein by reference for all purposes.

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 brake module 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-fault braking mode and a backup braking mode, the secondary brake module 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; a single return line hydraulically connecting the reservoir and each pump piston; a pump inlet attenuator hydraulically interposed between the reservoir and the pump piston and in direct fluid connection with the reservoir via the single return line; as well as an electronic control unit for controlling at least one of the secondary brake module and the master cylinder in response to at least one brake pressure signal; Therein, the pump inlet attenuator regulates the pressure in the single return line to reduce pressure fluctuations at the inlet side of each pump piston by mechanical pressure damping alone.

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

3. The braking system according to claim 2, wherein: Each isolation / dump control valve device is in fluid communication with 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 1, wherein: The secondary brake module includes a plurality of pump pistons associated with each of the first power transfer unit output and the second power transfer unit output.

5. 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.

6. The braking system according to claim 5, wherein: A first brake pressure sensor is hydraulically interposed between the first master cylinder output and a corresponding first traction control isolation valve, and a second brake pressure sensor is hydraulically interposed between the second master cylinder output and a corresponding second traction control isolation valve.

7. The braking system of claim 5, comprising an isolation / dump control valve arrangement associated with each wheel brake 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 / dump 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 / dump control valve arrangement of the second pair of wheel brakes.

8. The braking system of claim 7, comprising a first bypass isolation valve hydraulically disposed between the first traction control isolation valve and the front brake of the first pair of wheel brakes, and comprising a second bypass isolation valve hydraulically disposed between the second traction control isolation valve and the front brake of the second pair of wheel brakes, wherein The first bypass isolation valve and the second bypass isolation valve each have an orifice size that is larger than an orifice size of a corresponding isolation valve that isolates the dump control valve arrangement.

9. The braking system according to claim 8, wherein: Each of the first bypass isolation valve and the second bypass isolation valve is a normally open isolation valve and is configured to close in response to a higher hydraulic fluid pressure on an upstream side of the bypass isolation valve, the upstream side being a side closer to the master cylinder.

10. The brake system according to claim 8, wherein: Each of the first bypass isolation valve and the second bypass isolation valve is configured to open in response to a higher hydraulic fluid pressure on an upstream side of the bypass isolation valve, the upstream side being a side closer to the master cylinder.

11. The brake system according to claim 10, wherein: Each of the first bypass isolation valve and the second bypass isolation valve includes a check valve mechanism that selectively allows fluid to flow therethrough.

12. The brake system of claim 7, comprising a first bypass isolation valve hydraulically disposed between the first traction control isolation valve and the front brake of the first pair of wheel brakes, and comprising a second bypass isolation valve hydraulically disposed between the second traction control isolation valve and the front brake of the second pair of wheel brakes, wherein: Each of the first bypass isolation valve and the second bypass isolation valve is the same type of isolation valve as the isolation valve of the isolation / dump control valve arrangement.

13. The braking system of claim 7, comprising a first bypass isolation valve hydraulically disposed between the first traction control isolation valve and the front brake of the first pair of wheel brakes, and comprising a second bypass isolation valve hydraulically disposed between the second traction control isolation valve and the front brake of the second pair of wheel brakes, wherein Each of the first bypass isolation valve and the second bypass isolation valve is oriented in an opposite direction of fluid flow from an isolation valve of the isolation / dump control valve arrangement.

14. The brake system according to claim 1, wherein: At least a portion of the pump inlet attenuator is in fluid communication with an ambient space external to the brake system.

15. The brake system according to claim 7, wherein: The first bypass isolation valve and the second bypass isolation valve each include: a master cylinder passage in fluid communication with a corresponding first master cylinder outlet or a second master cylinder outlet; a brake-side passage in fluid communication with a corresponding front wheel brake; a longitudinally extending bypass valve sleeve; a bypass valve body having first and second longitudinally spaced body ends, a bypass body lumen extending between the first and second body ends, the bypass valve body spacing at least a portion of the bypass valve sleeve at least partially surrounding the first body end from at least the brake-side passage located adjacent the second body end; a bypass armature disposed within the bypass valve sleeve adjacent the first body end; a bypass tappet at least partially surrounded by the bypass armature and the bypass valve sleeve, the bypass tappet extending at least partially through the bypass body lumen, the bypass tappet selectively movable longitudinally within the bypass body lumen toward the bypass valve body by energization of the bypass armature; and a bypass valve seat carried by the bypass seat body directly adjacent to the second body end; wherein a bypass valve fluid path extends through a selected one of the master cylinder passage and the brake side passage, through the bypass valve seat, through at least one laterally extending side hole in the bypass valve body, through at least a portion of the bypass body lumen, and through the other of the master cylinder passage and the brake side passage; and wherein, in response to energizing the bypass armature to move the bypass tappet toward the second body end, the bypass tappet selectively engages the bypass valve seat to substantially block the bypass valve fluid path.

16. The braking system according to claim 15, wherein: The master cylinder passage is in indirect fluid communication with the corresponding first master cylinder outlet or the second master cylinder outlet via the corresponding first traction control isolation valve or the second traction control isolation valve, and the brake side passage is in direct fluid communication with the corresponding front wheel brake.

17. The brake system of claim 15, comprising a bypass bias spring mechanically disposed between the bypass tappet and at least a portion of the bypass valve body within the bypass body lumen, the bypass bias spring operative to bias the bypass tappet toward the first body end.

18. The brake system according to claim 1, wherein: The pump inlet attenuator comprises: a pump inlet attenuator piston having a piston head and a piston rod having at least one rib extending longitudinally thereof, said pump inlet attenuator piston being hydraulically interposed between said pump piston and an ambient space external to said brake system; a pump inlet attenuator piston chamber circumferentially surrounding the piston head; a pump inlet attenuator seal disposed laterally between the piston head and an inner wall of the pump inlet attenuator piston chamber, the pump inlet attenuator seal dividing the pump inlet attenuator piston chamber into a longitudinally spaced wet chamber portion and a dry chamber portion, the dry chamber portion being in fluid communication with an ambient space external to the brake system; and a pump inlet attenuator spring biasing the pump inlet attenuator piston toward the dry chamber portion; wherein the pump inlet attenuator piston moves longitudinally toward the pump piston in response to application of a first predetermined amount of negative pressure from the pump piston, and the pump inlet attenuator piston moves longitudinally away from the pump piston in response to at least one of a biasing force from the pump inlet attenuator spring, a second predetermined amount of negative pressure from the pump piston, and a predetermined amount of positive pressure from the pump piston, the second predetermined amount of negative pressure being less than the first predetermined amount of negative pressure.

19. The brake system according to claim 1, wherein: The pump inlet attenuator is a single pump inlet attenuator.

20. The brake system according to claim 1, wherein: The motor-driven master cylinder comprises: Master cylinder drive motor; Master cylinder main chamber; Master cylinder auxiliary chamber; a master cylinder master piston configured to selectively move longitudinally within the master cylinder master chamber in response to longitudinal movement imparted by the ball nut assembly along the ball nut axis; and a master cylinder slave piston configured to selectively move longitudinally within at least one of the master cylinder primary chamber and the master cylinder slave chamber in response to longitudinal movement imparted by the ball nut assembly along the ball nut axis, and wherein the master cylinder drive motor rotates a drive shaft having a drive shaft axis extending substantially parallel to the ball nut axis, and The rotational movement of the drive shaft is transmitted to the rotational movement of the spindle of the ball nut assembly via the master cylinder gear train.

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