BRAKE SYSTEMS WITH MOTOR-DRIVED MASTER CYLINDERS AND PUMP INTAKE DAMPERS

Abstract

A braking system comprises a master cylinder to generate pressure at a first and second MC output to actuate a first and second pair of wheel brakes. A secondary brake module is configured to supply fluid at a first and second PTU output to actuate the wheel brakes. The secondary brake module includes an electric motor configured to selectively pressurize the hydraulic fluid by transmitting a rotary motion to at least two pump pistons. A pump inlet damper is hydraulically positioned between a reservoir and the pump pistons and is in direct flow communication with the reservoir via a single return line. An electronic control unit controls the secondary brake module and / or the master cylinder in response to a brake pressure signal.The pump inlet damper regulates the pressure in the single return line to reduce pressure fluctuations on one inlet side of each pump piston solely through mechanical pressure damping.

Description

Related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 580,048 (Attorney Docket No. 301647-US-PSP), filed September 1, 2023, entitled "Brake Systems with Motor-Driven Master Cylinders and Pump Inlet Attenuators," the contents of which are incorporated herein by reference in their entirety.

[0002] This application relates to the technologies disclosed in one or more of U.S. Provisional Patent Application No. 63 / 580,042 (Attorney Docket No. 301699-US-PSP), filed on September 1, 2023, entitled "Brake Systems with Motor-Driven Master Cylinders and Low Pressure Accumulators"; U.S. Patent Application No. 18 / 474,657 (Attorney Docket No. 301158-US-NP), filed on the same date, entitled "Brake Systems with Motor-Driven Master Cylinders and Bypass Valves"; and concurrently filed U.S. patent application Ser. No. 18 / 474,678 (Attorney Docket No. 301699-US-NP) entitled “Brake Systems with Motor-Driven Master Cylinders and Low Pressure Accumulators,” the contents of which are incorporated herein by reference in their entirety. Technical area

[0003] This disclosure relates to an apparatus and method for use with braking systems having motor-driven master cylinders and pump inlet dampers, and more particularly to methods and apparatus of braking systems having motor-driven master cylinders, pump inlet dampers, and bypass valves. background

[0004] A braking system may include an anti-lock brake control system, which includes a hydraulic brake pressure generator, a brake pressure regulator provided in the pressurized fluid lines between the brake pressure generator and the wheel brakes and serves to vary the brake pressure by changing the volume of a chamber containing the hydraulic fluid, sensors for determining wheel rotational behavior, and electronic circuits for processing the sensor signals and generating brake pressure control signals. Braking systems may also include both an anti-lock brake control system and an anti-skid control system, which may use brake pressure regulators for controlled vehicle braking.

[0005] Descriptions of prior art braking systems can be found in U.S. Patent No. 10,730,501, entitled "Vehicle Brake System with Auxiliary Pressure Source," issued to Blaise Ganzel on August 4, 2020; U.S. Patent Application Publication No. 2020 / 0307538, entitled "Brake System with Multiple Pressure Sources," published by Blaise Ganzel on October 1, 2020; and U.S. Patent Application Publication No. 2023 / 0048447, entitled "Apparatus and Method for Control of a Hydraulic Brake System Including Manual Pushthrough," published by Blaise Ganzel on February 16, 2023, the contents of which are incorporated herein by reference in their entirety for all purposes. Brief description

[0006] In one aspect, alone or in combination with another aspect, a braking system for actuating a plurality of wheel brakes, including a first and a second pair of wheel brakes, is described. The system includes a reservoir and a motor-driven master cylinder (MC) operable during a non-failure normal braking mode of operation by actuating an electric motor of the master cylinder to generate brake actuation pressure at first and second MC outputs for hydraulically actuating the first and second pairs of wheel brakes, respectively. A secondary braking module is configured to selectively provide pressurized hydraulic fluid at first and second PTU outputs for actuating the first and second pairs of wheel brakes in a non-failure normal braking mode of operation and / or a secondary braking mode.The secondary braking module includes a PTU electric motor configured to selectively pressurize the hydraulic fluid by imparting rotary motion to at least two pump pistons. Each pump piston supplies pressurized hydraulic fluid to a corresponding one of the first and second PTU outputs. The first and second PTU outputs supply fluid to a corresponding one of the first and second pairs of wheel brakes. A single return line places the reservoir and each pump piston in hydraulic communication. A pump inlet damper is hydraulically disposed between the reservoir and the pump pistons and in direct fluid communication with the reservoir via the single return line. An electronic control unit is provided for controlling the secondary braking mode and / or the master cylinder in response to at least one brake pressure signal.The pump inlet damper regulates the pressure in the single return line to reduce pressure fluctuations on the inlet side of each pump piston solely through mechanical pressure damping. Short description of the drawings

[0007] For a better understanding, reference is made to the accompanying drawings, in which: Fig. 1 is a schematic hydraulic diagram of an exemplary braking system according to one aspect of the present invention; Fig. 2A is a schematic cross-sectional view of a component of the braking system of Fig. 1 with a first configuration; Fig. 2B is a schematic cross-sectional view of the component of Fig. 2A with a second configuration; Fig. 3 a schematic cross-sectional view of a component of the braking system of Fig. 1; Fig. 4 a cross-sectional view along line 4-4 of Fig. 3; Fig. 5 is a schematic hydraulic diagram of an exemplary braking system according to another aspect of the present invention; and Fig. 6 is a schematic side view of an exemplary arrangement of the components for one of the braking systems of Fig. 1 and Fig. 5. Description of aspects of revelation

[0008] Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this disclosure relates.

[0009] The invention comprises, consists of, or consists essentially of the following feature(s) in any combination.

[0010] Fig. 1 schematically illustrates 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 in which fluid pressure is utilized to apply braking forces to the braking systems 100. The braking system 100 may suitably be used with a land vehicle, such as a four-wheel motor vehicle in which a wheel brake is associated with each wheel. Furthermore, the braking system 100 may be provided with other braking functions such as ABS and other slip control features for effectively braking the vehicle. Components of the braking system 100 may be housed in one or more blocks or housings. The blocks or housings may be manufactured from a solid material, such as aluminum, which may be drilled, machined, or otherwise formed to accommodate the various components. Fluid lines may also be formed within the block or housing.

[0011] In the illustrated embodiment of the braking system 100 of Fig. 1, there are four wheel brakes 102, each of which may include any suitable wheel brake structure operated electrically and / or by the application of pressurized brake fluid. For example, each of the wheel brakes 102 may include a brake caliper mounted to the vehicle to engage a friction element (such as a brake disc) rotating with a vehicle wheel to effect braking of the associated vehicle wheel. The wheel brakes 102 may be associated with any combination of front and rear wheels of the vehicle having the corresponding braking system 100 installed. For example, the braking systems 100 may each be configured as a vertically split or diagonally split system.For the purposes of this description, no differentiation is made between the designs of the various wheel brakes 102, although one of ordinary skill in the art could readily provide a suitable brake arrangement for a particular operating environment. As described herein, the wheel brakes 102 include a first and a second pair of wheel brakes 102, the first and second pairs being designated RV / LH and LV / RH for descriptive purposes, as shown in FIG. Fig. 1. However, the pairs LV / LH and RV / RH or RV / LV and RH / LH could also or instead be defined for the braking system 100, as desired.

[0012] For the purposes of the description, it is also assumed that a deceleration signal transmitter (shown schematically at 104) is configured to provide a brake signal, wired or wirelessly, corresponding to a desired braking action from an operator of the vehicle. The deceleration signal transmitter 104 could include, among other things, a brake pedal, an autonomous brake controller, and / or any other suitable scheme for generating a brake signal with which the braking system 100 can be actuated.

[0013] The brake systems 100 also include a fluid reservoir 106. The reservoir 106 stores and preserves hydraulic fluid for the brake system 100. The fluid in the reservoir 106 is preferably stored at or near atmospheric pressure, but the fluid may be stored at other pressures as desired. The reservoir 106, as schematically shown, has three containers or areas in Fig. 1 with fluid lines connected thereto. The regions may be divided by some internal walls in the reservoir 106 and are intended to prevent complete emptying of the reservoir 106 if one of the regions is emptied due to a leak through one of the three lines connected to the reservoir 106. Alternatively, the reservoir 106 may comprise several separate housings. The reservoir 106 may include at least one liquid level sensor 108 for detecting the liquid level of one or more of the regions of the reservoir 106.

[0014] A motor-driven master cylinder ("MC" or "primary power transmission unit") 110 (which may be a dual-chamber master cylinder 110, also known as a tandem power transmission unit) of each braking system 100 acts as a pressure source for supplying a desired pressure level to the hydraulically actuated 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 Ser. No. 17 / 708,070, entitled "Tandem Power Transmission Unit and Brake Systems Using Same," filed March 30, 2022 (Attorney Docket No. 211835-US-NP), the contents of which are incorporated herein by reference in their entirety. The master cylinder 110 is operable during a non-failure normal braking mode of operation by actuating an electric motor 112 of the master cylinder 110 to apply a brake application pressure at a first or second brake application point.a second MC output 114 or 116 for hydraulically actuating the first and second pair of wheel brakes 102.

[0015] Following a brake application, fluid from the wheel brakes 102 may be returned to the master cylinder 110 and / or redirected to the reservoir 106. It is also contemplated that other configurations (not shown) of the braking system 100 could include hydraulic control of only a selected one or more of the wheel brakes (the others would then be electrically controlled / actuated). One of ordinary skill in the art would readily be able to provide such an arrangement for a desired operating environment by following aspects of the present invention.

[0016] An iso / drain control valve assembly is associated with each of the plurality of wheel brakes 102. Each iso / drain control valve assembly includes an iso valve 118 and a drain valve 120 for providing a desired fluid line to an associated wheel brake 102. Reservoir 106 is hydraulically connected to master cylinder 110 and to each of the iso / drain control valve assemblies, such as via return line 136. The iso / drain control valve assemblies each include iso and drain valves 118 and 120 arranged in series. The normally open iso valve 118 for each iso / drain control valve assembly is hydraulically positioned between a respective wheel brake 102 and the master cylinder 110, and the normally closed drain valve 120 for each iso / drain control valve assembly is hydraulically positioned between a respective wheel brake 102 and the reservoir 106 for the corresponding wheel brake 102.

[0017] The iso / drain control valve assemblies may selectively provide slip control to at least one wheel brake 102 operated by the master cylinder 110 and / or the secondary brake module described below. More generally, the iso / drain control valve assembly and / or other valves of the braking system 100, any of which may be electromagnetically actuated and may have any suitable configurations, may be used to assist in providing controlled braking events, such as, among others, ABS, traction control, vehicle stability control, dynamic brake-force distribution, blending with regenerative braking, and autonomous braking.

[0018] A first traction control isovalve 122 is hydraulically connected between the master cylinder 110 and at least one iso / drain control valve assembly via the first MC outlet 114. A second traction control isovalve 124 is hydraulically connected between the master cylinder 110 and at least one iso / drain control valve assembly via the second MC outlet 116. As shown in the figures, it is contemplated that an iso / drain control valve assembly is associated with each wheel brake 102 of the first and second pairs of wheel brakes. The first traction control isovalve 122 is hydraulically connected between the motor-driven master cylinder 110 and the iso / drain control valve assemblies of the first pair of wheel brakes 102. Likewise, the second traction control iso valve 124 is hydraulically disposed between the motor-driven master cylinder 110 and the iso / dump control valve assemblies of the second pair of wheel brakes 102.

[0019] A 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 PTU electric motor 128 (different from the electric motor 112 included in the master cylinder 110) that imparts rotary motion to each pump piston 126 for selectively supplying pressurized hydraulic fluid to the isolating / draining control valve assembly of at least one wheel brake 102 associated with the pump piston 126. As shown in Fig. 1, one pump piston 126 is associated with two wheel brakes 102, for a total of two pump pistons 126 in the braking system 100. Together, the pump piston(s) 126 and the PTU electric motor 128 may be considered a secondary braking module (or "secondary power transfer unit") of the braking system 100. For example, the two pump pistons 126 shown in the figures may supply pressurized hydraulic fluid to the respective wheel brakes 102 via the respective isolating / bleeding control valve assemblies (if present) at the first and second PTU outputs 130 and 132, respectively, to apply the first and second pairs of wheel brakes 102 in a non-failure normal braking mode of operation and / or a secondary braking mode. The first and second PTU outputs 130 and 132 can supply fluid to a corresponding one of the first and second pairs of wheel brakes 102.It is contemplated that in some configurations of the braking system 100, multiple pump pistons 126 could be associated with the first and second PTU outputs 130 and 132.

[0020] The secondary brake modules of the braking systems 100 act as a pressure source for supplying a desired pressure level to selected ones of the wheel brakes 102 in a backup or "failure" situation when the master cylinder 110 is unable to supply fluid to those selected wheel brakes 102 for any reason. Accordingly, each of the secondary brake modules is in direct fluid communication with the reservoir 106 for exchanging hydraulic fluid between these components without having to route the fluid through a (possibly failed) motor-driven master cylinder 110 or other structure of the braking system 100.

[0021] The secondary brake modules may be used to selectively supply hydraulic fluid to at least one of the wheel brakes 102 in an auxiliary braking mode, but also in an augmented braking mode, which may operate alone and / or in conjunction with either the auxiliary braking mode or a non-failure normal braking mode of operation. Examples of suitable augmented braking mode functions available to the braking systems 100 include, but are not limited to, "overboost" (where higher pressure is supplied to a particular brake than would normally be available from the master cylinder 110 alone) and "volume-add" (where more fluid is supplied to a particular brake than would normally be available from the master cylinder 110 alone). These augmented braking modes may be implemented in some operating environments by fluidly connecting the first and second MC outputs 114 and 116, respectively.116 to a pump inlet of at least one pump piston 126 for selectively supplying pressurized hydraulic fluid to the pump piston(s) 126. For example, in the non-failure normal braking mode and / or the auxiliary braking mode, the secondary brake module may then supply hydraulic fluid at a boosted pressure (greater than that received from the master cylinder 110) to the first and / or second PTU outputs 130 or 132.

[0022] As can be seen, each isolating / dump control valve assembly in the braking systems 100 shown in the figures is in direct or indirect flow communication with a selected one of the first and second MC outputs 114 and 116 and a selected one of the first and second PTU outputs 130 and 132 for selectively receiving pressurized fluid therefrom, e.g., during various braking modes or otherwise as desired. One of ordinary skill in the art will readily be able to provide a braking system 100 as desired for a particular operating environment.

[0023] The Fig. The braking system 100 shown in Figure 1 further includes at least one electronic control unit ("ECU") 134 for controlling the master cylinder 110 and / or the secondary braking module (via the PTU electric motor 128) in response to at least one brake pressure signal, with first and second ECUs 134A, 134B being shown and described herein. The ECUs 134A, 134B may include microprocessors and other electrical circuitry. The ECUs 134A, 134B receive various signals, process signals, and control the operation of various electrical components of a respective 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 the reservoir fluid level sensor(s) 108, pressure sensors, stroke sensors, switches, wheel speed sensors, and steering angle sensors.The ECUs 134A, 134B may also be connected to an external module (not shown) for receiving information regarding the vehicle's yaw rate, lateral acceleration, longitudinal acceleration, or other vehicle operating characteristics for any reason, such as, but not limited to, controlling the braking system 100 during vehicle braking, stability operation, or other operating modes. Furthermore, the ECUs 134A, 134B may be connected to the instrument cluster for acquiring and providing information 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 brake master cylinder 110 or the PTU electric motor 128.

[0024] The first and second ECUs 134A and 134B may divide the control tasks for the braking system 100 in any desired manner and may be readily configured by one of ordinary skill in the art for a particular braking system deployment environment. However, it is contemplated that any control tasks performed by one or more ECUs 134 may be performed in response to at least one brake pressure signal and / or a brake signal generated by the deceleration signal transmitter 104. For example, the first ECU 134A may be operable to control the electric motor 136 of the brake master cylinder 110. The second ECU 134B may be operable to control the PTU electric motor 128, at least one of the iso / dump control valve assemblies, and the first and / or second traction control iso valves 122, 124.

[0025] A "brake pressure signal" is indicated above as at least one input that an ECU 134 can consider and, in response, control one or more other components of the braking system 100 to achieve desired braking results for a particular operating environment. One possible origin for the brake pressure signal is a brake pressure sensor. For example, and as shown in the figures, the braking system 100 may include at least one, such as at least two, brake pressure sensors 138. As shown in Fig. 1, a first brake pressure sensor 138A may be hydraulically disposed between the first traction control isovalve 122 and the master cylinder 110, and a second brake pressure sensor 138B may be hydraulically disposed between the second traction control isovalve 124 and a master cylinder 110. One of ordinary skill in the art can readily provide a desired number / location / type of pressure sensor 138 for a particular braking system 100.

[0026] A first bypass iso-valve 140 is hydraulically arranged between the first traction control iso-valve 122 and a front wheel brake of the first pair of wheel brakes 102 in parallel with the iso / drain control valve arrangement corresponding to the front wheel brake of the first pair of wheel brakes 102. A second bypass iso-valve 142 is hydraulically arranged between the second traction control iso-valve 124 and a front wheel brake of the second pair of wheel brakes 102 in parallel with the iso / drain control valve arrangement corresponding to the front wheel brake of the second pair of wheel brakes 102. The first and second bypass iso-valves 140 and 142, which are Fig. 1 are, as shown, normally open iso valves.

[0027] The first and second bypass iso valves 140 and 142 are configured to close in response to higher hydraulic fluid pressure on an upstream (i.e., closer to the master cylinder 110) side of the respective bypass iso valves 140 and 142 to enable the braking system 100 to maintain the first and second bypass iso valves 140 and 142 closed with a relatively low current draw from the system. The first and second bypass iso-valves 140 and 142 also have an opening size that is larger than an opening size of the iso-valve 118 of the corresponding iso / drain control valve assembly and are oriented in a fluid flow direction opposite that of the iso-valve 118 of the corresponding iso / drain control valve assembly (i.e., connected in a "reverse" direction with respect to the corresponding iso-valves 118).As a result, the first and second bypass iso-valves 140 and 142 can thus help quickly apply pressure to the wheel brakes 102 in a "peak application" situation. (It should be noted that the first and second bypass iso-valves 140 and 142 can also have an orifice size that is larger than an orifice size of the corresponding first and second traction control iso-valves 122 and 124.) An exemplary use of the first and second bypass iso-valves 140 and 142 is when an undesirably high peak application may occur once an iso-valve 118 closes because the electric motor 112 of the master cylinder 110 has inertia and requires a predetermined amount of time to stop rotating and drive the piston in the chamber of the master cylinder 110.The presence of the first and second bypass iso-valves 140 and 142 when handling a "peak application" situation also allows the use of a smaller corresponding iso-valve 118, since the electric motor 112 does not have to rotate as fast to achieve the desired fluid pressure level at the associated wheel brake 102. Referring now to FIG. Fig. 2A-2B the structure of the first and second bypass iso valves 140 and 142 is discussed in more detail.

[0028] An electric brake motor 144 may be associated with each of the rear wheel brakes of the front and rear pairs of wheel brakes 102. If present, the electric brake motors 144 may be operated in at least the auxiliary braking mode and may be controlled by an opposing ECU 134 (in response to the brake signal), such as the electric motor 112 of the master cylinder 110 if multiple ECUs 134 are present. For example, if the first ECU 134A controls the electric motor 112 of the master cylinder 110, the second ECU 134B may control the PTU electric motor 128 and the electric brake motors 144 for redundancy in the braking system 100 in the event that the first ECU 134A fails.

[0029] With the braking system 100 of Fig. 1, the single return line 136 places the reservoir 106 and each pump piston 126 in hydraulic communication. The braking system 100 also includes a pump inlet damper 146 hydraulically disposed between the reservoir 106 and the pump pistons 126 for "damping" fluid flow therebetween. The pump inlet damper 146 is in direct fluid communication with the reservoir 106 via the single return line 136 and regulates the pressure in the single return line 136 to reduce pressure fluctuations on an inlet side of each pump piston 126 solely through mechanical pressure damping. At least a portion of the pump inlet damper 146 may be in fluid communication with the surrounding space external to the braking system 100, as described below with reference to Fig. 3-4. The pump inlet damper 146 may be a single pump inlet damper 146, as shown and discussed herein, or it is contemplated that multiple pump inlet dampers (not shown) may be provided for certain operating environments of the braking system 100.

[0030] In known braking systems, acceleration and deceleration of the fluid column in the return line 136 is required due to flow vibrations generated at the inlets of the pump pistons 126. This causes undesirable pressure fluctuations and reduced volumetric pumping efficiency. In turn, the presence of the pump inlet damper 146 enables improved pump build-up rate performance with a smaller diameter and / or longer return line 136. The packaging of the pump inlet damper 146 (or "pump inlet damping device") can be integrated into the return line 136 (e.g., within a reservoir hose adapter of the braking system 100) or "piggybacked" within a housing body structure of another component (e.g., a secondary braking module).Because the pump pistons 126 of the brake system 100 draw fluid at relatively low pressure from the return line 136 (into which the pump inlet damper 146 is integrated), the pump inlet damper 146 does not need to be able to withstand the relatively high pressures developed in lines leading from the master cylinder 110. Thus, the pump inlet damper 146 can serve both / all pump pistons 126 simultaneously, but still with relatively inexpensive (e.g., molded plastic) components because the pump inlet damper 146 operates in a low-pressure environment, as shown.

[0031] Fig. 2A-2B are described below as relating to the first bypass iso-valve 140 for simplicity, however, the second bypass iso-valve 142 will be similarly structured in many application environments. Fig. 2A shows the bypass valve 140, 142 in an open state, and in Fig. 2B, the bypass valve 140, 142 is energized to a closed state. With reference to Fig. 2A-2B, the first and second bypass iso-valves 140 and 142 may each include an MC passage 246 in fluid communication with a corresponding first or second MC output 114, 116, a brake-side passage 248 in fluid communication with a corresponding front wheel brake 102, and a longitudinally extending bypass valve sleeve 250. The MC passage 246 may be in indirect fluid communication with the corresponding first or second MC output 114, 116 via a corresponding first or second traction control iso-valve 122, 124. The brake-side passage 248 may be in direct fluid communication with the corresponding front wheel brake 102. One of ordinary skill in the art can readily configure a braking system 100 including one or more bypass iso valves 140 and 142 for a particular application environment.

[0032] A bypass valve body 252 has first and second body ends 254 and 256, respectively, which are longitudinally spaced apart from one another, with a bypass body cavity 258 extending therebetween. The bypass valve body 252 spaces at least a portion of the bypass valve sleeve 250 (at least partially surrounding the first body end 254) away from at least the brake-side passage 248 positioned adjacent the second body end 256. A bypass armature 260 is positioned within the bypass valve sleeve 250 adjacent the first body end 256. A bypass plunger 262 is at least partially surrounded by the bypass armature 260 and the bypass valve sleeve 250. The bypass plunger 262 extends at least partially through the bypass body cavity 258. The bypass plunger 262 is selectively moved longitudinally within the bypass body cavity 258 toward the bypass valve body 252 by energizing the bypass armature 260.A bypass biasing spring 264 is mechanically disposed between the bypass plunger 262 and at least a portion of the bypass valve body 252 within the bypass body cavity 258. The bypass biasing spring 264 is operable to bias the bypass plunger 262 toward the first body end 254. A bypass valve seat 266 is supported by a bypass seat body 268 positioned directly adjacent the second body end 256.

[0033] Any desired number of bypass valve filters 270 may be provided, and are shown here as a belt filter 270A and a disc filter 270B associated with the MC passage 246 and the brake-side passage 248, respectively. An air gap spacer 272 may be provided to assist in maintaining tolerances and / or transferring forces between components, as desired. The bypass valve 140, 142 may be supported by a housing block 274 of a braking system 100, and at least a portion of the MC passage 246 and the brake-side passage 248 may be formed in the housing block 274. The bypass valve body 252 or any other desired components of the bypass valve 140, 142 may be retained in a valve bore 276 of the housing block 274 by caulking, crimping, welding, soldering, adhesives, fasteners, or any other desired retention scheme.

[0034] A bypass valve fluid path F extends (bidirectionally) through a selected one among the MC passage 246 and the brake-side passage 248, past the bypass valve seat 266, through at least one laterally extending side recess 278 in the bypass valve body 252, through at least a portion of the bypass body cavity 258, and through the other among the MC passage 246 and the brake-side passage 248 to bring these two passages into fluid communication. This is the "normally open" position shown in Fig. 2A is shown.

[0035] In the “energized to the closed state” position, which is Fig. 2B, the bypass plunger 262 selectively engages the bypass valve seat 266 to substantially cover the bypass valve fluid path F in response to energization of the bypass armature 260, thereby moving the bypass plunger 262 toward the second body end 256.

[0036] The pump inlet attenuator (PIA) 146 is installed in Fig. 3-4. A PIA piston 380 includes a piston head 382 and a piston skirt 384. The piston skirt 384 has at least one rib 385 extending longitudinally therealong—as shown, a plurality of ribs 385 together define a piston skirt 384 having an at least partially cruciform cross-section to facilitate brake fluid flow within the pump inlet damper 146. The PIA piston 380 is hydraulically disposed between the pump pistons 126 and a surrounding space "A" external to the brake system 100.

[0037] A PIA piston chamber 386 circumferentially surrounds the piston head 382, ​​and the piston head 382 moves longitudinally (ie, parallel to the arrow “L” of Fig. 3) reciprocates within the PIA piston chamber 386. A PIA seal 388 is disposed laterally between the piston head 382 and an inner wall 390 of the PIA piston chamber 386 to divide the PIA piston chamber 386 into wet and dry chamber regions 392 and 394, respectively, spaced longitudinally apart. The dry chamber region 394 is the portion of the pump inlet damper 146 that communicates with the surrounding space A outside the braking system 100. A PIA spring 396 biases the PIA piston 380 toward the dry chamber region 394. At least one retainer 398 may be positioned at an outermost portion of the piston head 380 to prevent the entire face of the piston head 380 from contacting the solid retaining disk 402. Air may be exchanged between the surrounding space A and the drying chamber area 384 via a vent line 402.In contrast, it is contemplated that the retaining disc 402 could include one or more perforations, through-holes, or be made at least in part of an air-permeable material (not shown) to allow air exchange with the surrounding space A directly therethrough, without the vent line 402.

[0038] The PIA piston 380 moves longitudinally to the pump pistons (schematically at 126 in Fig. 6) in response to the application of a first predetermined level of vacuum from the pump pistons 126. The PIA piston 380 moves longitudinally away from the pump pistons 126 (i.e., toward the retainer disk 402) in response to a biasing force from the PIA spring 396 and / or a second predetermined level of vacuum (wherein the second predetermined level of vacuum is less than the first predetermined level of vacuum) from the pump pistons 126 and / or a predetermined level of positive pressure from the pump pistons 126. As shown in Fig. 3, the illustrated pump inlet damper 146 has a "spigot"-type connection with a gasket therearound, and it is inserted into the housing block 274 and thus into fluid communication with the pump pistons 136. However, it is contemplated that any suitable placement and mounting scheme for connecting the pump inlet damper 146 within the braking system 100 could be provided as desired. More generally, one of ordinary skill in the art can readily provide a suitable pump inlet damper 146 for a particular application of the braking system 100.

[0039] With reference now to Fig. 1, the reservoir 106 and the motor-driven master cylinder 110 may be positioned together in a first housing (indicated schematically in the figures by the dashed line "1"), and the secondary brake module may be positioned in a second housing (indicated schematically in the figures by the dashed line "2") spaced from the first housing. Optionally, and as also in Fig. 1, the iso / dump control valve assemblies, the first and second bypass iso valves 140 and 142 and / or the first and second traction control iso valves 122 and 124 may also be positioned in the second housing.

[0040] The first and second housings (and components contained / positioned therewith) of any braking system 100 may be designed and configured by one of ordinary skill in the art for a particular application environment based on factors including, but not limited to, achieving desired design, manufacturing, maintenance, space utilization within the vehicle, cost, size, and / or regulatory compliance, or the like.

[0041] Fig. 5 illustrates a second embodiment of a braking system 100. The braking system of Fig. 5 is similar to the braking system of Fig. 1, and thus structures of Fig. 5, which are in accordance with those made with reference to Fig. 1 have the same reference numerals. The description of identical elements and operations similar to those in the previously described first embodiment will not be repeated with respect to the second embodiment, but should be considered incorporated by reference accordingly.

[0042] With the braking system 100 of Fig. 5, the first and second bypass iso-valves 140' and 142' are of the same iso-valve type as the iso-valve 118 of the corresponding iso / drain control valve arrangement (instead of the bypass iso-valve 140, 142 of Fig. 2A-2B of the first embodiment of the braking system 100 shown in Fig. 1). This means that in the second embodiment of the device shown in Fig. 5, the first and second bypass iso-valves 140' and 142' include a check valve mechanism 504 that selectively permits fluid flow therethrough. The first and second bypass iso-valves 140' and 142' are configured to open in response to a higher hydraulic fluid pressure on an upstream (i.e., closer to the master cylinder 110) side of the bypass iso-valve 140' and 142' - again in contrast to the arrangement of Fig. 1. In the braking system 100 of Fig. 5, the openings of the first and second bypass iso-valves 140` and 142' are larger than the corresponding openings of the first and second bypass iso-valves 140 and 142 discussed above, at least in part because the first and second bypass iso-valves 140` and 142' in the braking system 100 of Fig. 4 are not used for pressure control, but instead remain closed during slip control events. Fig. 5 shown braking system 100 can be simpler than that of Fig. 1, since the braking system of Fig. 5 fewer valve types that need to be deployed and configured.

[0043] Fig. Figure 6 schematically illustrates a physical arrangement of at least a portion of a braking system 100, which may be used, for example, as at least a portion of a first housing “1” of the first or second embodiment of the braking systems 100 shown in Fig. 1 and Fig. 5. In all of these braking systems 100, the motor-driven master cylinder 110 includes an MC drive electric motor 112 (as previously mentioned), a primary MC chamber 608, and a secondary MC chamber 610. A primary MC piston 612 is configured for selective longitudinal movement within the primary MC chamber 608 in response to longitudinal movement imparted by a ball nut assembly 614 along a ball nut axis "BNA (Ball Nut Axis)". (The "longitudinal" direction is used in Fig. 6 by the arrow "L".) A secondary MC piston 616 is configured for selective longitudinal movement within the primary and / or secondary MC chambers 608 and 610 in response to longitudinal movement imparted by the ball nut assembly 614 along the ball nut axis BNA.

[0044] The MC drive motor 112 rotates a drive shaft 618, which has a drive shaft axis ("DSA (Drive Shaft Axis)") that is substantially parallel to the ball nut axis BNA. A rotary motion of the drive shaft 618 is translated via an MC gear set 622 into a rotary motion of a spindle 620 of the ball nut assembly 614. It is emphasized that in the Fig.6, the rotational motion from an MC drive electric motor 112 is transferred to the drive shaft 618, and the MC gear set 622 then transfers this rotational motion to a laterally spaced and substantially parallel spindle 620 to rotate the ball nut assembly 614 and, in response, drive the master cylinder 110. This "reversal" of the drive force from the MC drive electric motor 112 enables the provision of a physical configuration with a compact packaging size and a reduced footprint for the components included in the braking system 100.

[0045] It is contemplated that various other components, such as electric service and / or parking brake motors, could be provided by one of ordinary skill in the art to achieve the desired configurations for particular operating environments in any of the braking systems described herein. For example, while a number of filters and pressure sensors are shown in the figures, their specific description has been omitted here for the sake of brevity, as it would be readily understood by one of ordinary skill in the art how to provide a desired number, placement, and / or operation of filters, sensors, and any other components as desired for a particular operating environment of the present invention.

[0046] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context expressly indicates otherwise. It is further understood that the terms "comprises" and / or "comprising," as used herein, may indicate the presence of recited features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0047] As used herein, the term “and / or” may include any and all combinations of one or more of the associated listed elements.

[0048] It should be understood that when an element is described as being "on," "attached to," "connected to," "coupled to," "in contact with," "adjacent," etc., another element, it may be directly on, attached to, connected to, coupled to, in contact with, or adjacent to the other element, or there may be intervening elements. Conversely, when an element is described as being, for example, "directly on," "directly attached to," "directly connected to," "directly coupled to," "directly in contact with," or "directly adjacent" to another element, no intervening elements are present. One of ordinary skill in the art will further appreciate that references to a structure or feature being "directly adjacent" to another feature may include portions overlying or underlying the adjacent feature, whereas a structure or feature beingthat is positioned "next to" another feature may not have any portions that overlie or lie beneath the adjacent feature.

[0049] Spatial terms such as "below," "beneath," "lower," "above," "upper," "proximal," "distal," and the like may be used herein for convenience of description to more easily describe the relationship of one element or feature to one or more other elements or features as illustrated in the figures. It should be understood that spatial terms may encompass various orientations of a device in use or operation in addition to the orientation shown in the figures. For example, if a device is turned over in the figures, elements described as being "below" or "below" other elements or features would then be oriented "above" the other elements or features.

[0050] As used herein, the phrase "X and / or Y" can be interpreted to include X, Y, or a combination of X and Y. For example, if an element is described as having X and / or Y, the element may, at a given time, have X, Y, or a combination of X and Y, although the selection could vary from time to time. In contrast, the phrase "at least one of X" can be interpreted to include one or more Xs.

[0051] It should be understood that while the terms "first," "second," etc., may be used herein to describe various elements, these elements are not intended to be limited by these terms. These terms are used merely to distinguish one element from another. Thus, a "first" element discussed below could also be referred to as a "second" element without departing from the teachings of the present disclosure. The order of operations (or steps) is not limited to the order shown in the claims or the figures unless expressly stated otherwise.

[0052] Although aspects of the present disclosure have been specifically shown and described with reference to the above exemplary aspects, it will be apparent to one of ordinary skill in the art that various additional aspects may be contemplated. For example, the specific methods of using the device described above are merely exemplary; one of ordinary skill in the art could readily determine any number of tools, sequences of steps, or other means / options for placing the above-described device or its components in positions substantially similar to those shown and described herein.To maintain clarity in the figures, certain repetitive components shown have not been specifically numbered. However, one of ordinary skill in the art will recognize, based on the numbered components, the element numbers that should be assigned to the unnumbered components. No distinction between similar components is intended or implied by the mere presence or absence of an element number in the figures. Any of the described structures and components could be integrally formed as a single unitary or monolithic piece or composed of separate subcomponents, both of which configurations could incorporate any suitable starting material or custom-fabricated components and / or any suitable material or combination of materials.Any of the described structures and components could be disposable or reusable, as desired for a particular operating environment. Each component could be provided with a user-perceivable marking to indicate a material, configuration, at least one dimension, or the like specific to that component, where the user-perceivable marking may assist the user in selecting a component from a group of similar components for a particular operating environment. A "predetermined" state may be determined at any time before the manipulated structures actually reach that state, and the "predetermination" may occur as late as immediately before the structure reaches the predetermined state.The term "substantially" is used herein to indicate a characteristic that is largely, but not necessarily completely, that which is specified—a "substantially" exhibited characteristic allows for the possibility of some relatively minor inclusion of an element not corresponding to the characteristic. While certain components described herein are depicted as having specific geometric shapes, all of the structures of the present disclosure may have any suitable shapes, sizes, configurations, relative relationships, cross-sectional areas, or any other physical characteristics, as desired for a particular application.Any structures or features described with reference to one aspect or configuration could be provided individually or in combination with other structures or features in any other aspect or configuration, as it would be impractical to describe all aspects and configurations discussed herein as having all of the options discussed with respect to all other aspects and configurations. An apparatus or method incorporating any of these features is intended to be within the scope of the present disclosure, which is determined based on the following claims and any equivalents thereof.

[0053] Further aspects, objects and advantages may be determined by considering the drawings, the disclosure and the appended claims. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 580,048

[0001] US 63 / 580,042

[0002] US 18 / 474,657

[0002] US 18 / 474,678

[0002] US 10,730,501

[0005] US 2020 / 0307538

[0005] US 2023 / 0048447

[0005] US 17 / 708,070

[0014] Cited non-patent literature

[0000] Vehicle Brake System with Auxiliary Pressure Source”, in October 1, 2020

[0005] Brake System with Multiple Pressure Sources” and on 16 February 2023 v

[0005] Apparatus and Method for Control of a Hydraulic Brake System Including Manual Pushthrough

[0005]

Claims

[1] A braking system for actuating a plurality of wheel brakes comprising a first and a second pair of wheel brakes, the system comprising: a reservoir; a motor-driven master cylinder operable during a non-failure normal braking mode of operation by actuating an electric motor of the master cylinder to generate a brake actuation pressure at first and second MC outputs for hydraulically actuating the first and second pairs of wheel brakes, respectively; a secondary brake module configured to selectively provide pressurized hydraulic fluid at first and second PTU outputs for actuating the first and second pairs of wheel brakes in a non-failure normal braking mode and / or an auxiliary braking mode, the secondary brake module comprising a PTU electric motor configured to selectively pressurize the hydraulic fluid by imparting rotational motion to at least two pump pistons, each pump piston supplying pressurized hydraulic fluid to a corresponding one of the first and second PTU outputs, the first and second PTU outputs supplying fluid to a corresponding one of the first and second pairs of wheel brakes; a single return line that puts the reservoir and each pump piston in hydraulic connection; a pump inlet damper hydraulically disposed between the reservoir and the pump pistons and in direct flow communication with the reservoir via the single return line; and an electronic control unit for controlling the secondary braking mode and / or the master cylinder in response to at least one brake pressure signal; wherein the pump inlet damper regulates the pressure in the single return line to reduce pressure fluctuations on the inlet side of each pump piston solely by mechanical pressure damping. [2] The braking system of claim 1, including an iso / drain control valve assembly associated with each of the plurality of wheel brakes, each iso / drain control valve assembly being controlled by the electronic control unit. [3] The braking system of claim 2, wherein each isolating / draining control valve assembly is in fluid communication with a selected one of the first and second MC outputs and a selected one of the first and second PTU outputs for selectively receiving pressurized fluid therefrom. [4] The braking system of claim 1, wherein the secondary braking module includes a plurality of pump pistons associated with the first and second PTU outputs. [5] A braking system according to claim 1, comprising: a first traction control isovalve hydraulically connected between the motor-driven master cylinder and the first pair of wheel brakes via the first MC outlet; and a second traction control isovalve hydraulically connected between the engine-driven master cylinder and the second pair of wheel brakes via the second MC outlet. [6] A braking system according to claim 5, wherein a first brake pressure sensor is hydraulically arranged between the first MC output and a corresponding first bypass iso valve and a second brake pressure sensor is hydraulically arranged between the second MC output and a corresponding second bypass iso valve. [7] A braking system according to claim 5, comprising an iso / drain control valve assembly associated with each of the first and second pairs of wheel brakes, the first traction control iso valve being hydraulically connected between the motor-driven master cylinder and the iso / drain control valve assemblies of the first pair of wheel brakes, and the second traction control iso valve being hydraulically connected between the motor-driven master cylinder and the iso / drain control valve assemblies of the second pair of wheel brakes. [8] The braking system of claim 7, including a first bypass iso-valve hydraulically disposed between the first traction control iso-valve and a front wheel brake of the first pair of wheel brakes, and a second bypass iso-valve hydraulically disposed between the second traction control iso-valve and a front wheel brake of the second pair of wheel brakes, wherein the first and second bypass iso-valves have an opening size that is larger than an opening size of the iso-valve 118 of the corresponding iso / bleed control valve assembly. [9] A braking system according to claim 8, wherein the first and second bypass iso-valves are a normally open iso-valve and are configured to close in response to a higher hydraulic fluid pressure on an upstream (ie, closer to the master cylinder) side of the bypass valve. [10] A braking system according to claim 8, wherein the first and second bypass iso-valves are configured to open in response to a higher hydraulic fluid pressure on an upstream (ie, closer to the master cylinder) side of the bypass valve. [11] The braking system of claim 10, wherein the first and second bypass iso-valves include a check valve mechanism that selectively permits fluid flow therethrough. [12] A braking system according to claim 7, comprising a first bypass iso-valve hydraulically arranged between the first traction control iso-valve and a front wheel brake of the first pair of wheel brakes, and a second bypass iso-valve hydraulically arranged between the second traction control iso-valve and a front wheel brake of the second pair of wheel brakes, wherein the first and second bypass iso-valves are of the same iso-valve type as the iso-valve of the iso / dump control valve assembly. [13] A braking system according to claim 7, comprising a first bypass iso-valve hydraulically arranged between the first traction control iso-valve and a front wheel brake of the first pair of wheel brakes, and a second bypass iso-valve hydraulically arranged between the second traction control iso-valve and a front wheel brake of the second pair of wheel brakes, the first and second bypass iso-valves being oriented in a fluid flow direction opposite that of the iso-valve of the iso / dump control valve assembly. [14] A braking system according to claim 1, wherein at least a portion of the pump inlet damper is in fluid communication with a surrounding space external to the braking system. [15] A braking system according to claim 7, wherein the first and second bypass iso valves each comprise: an MC passage in flow communication with a corresponding first or second MC outlet; a brake-side passage in flow connection with a corresponding front wheel brake; a longitudinally extending bypass valve sleeve; a bypass valve body having first and second body ends longitudinally spaced apart from one another, with a bypass body cavity extending therebetween, the bypass valve body spacing at least a portion of the bypass valve sleeve at least partially surrounding the first body end away from at least the brake-side passage positioned adjacent the second body end; a bypass armature positioned in the bypass valve sleeve adjacent the first body end; a bypass plunger at least partially surrounded by the bypass armature and the bypass valve sleeve, the bypass plunger extending at least partially through the bypass body cavity, the bypass plunger being selectively moved longitudinally within the bypass body cavity toward the bypass valve body by energizing the bypass armature; and a bypass valve seat supported by a bypass seat body positioned directly adjacent to the second body end; wherein a bypass valve fluid path extends through a selected one of the MC passage and the brake-side passage, through the bypass valve seat, through at least one laterally extending side recess in the bypass valve body, through at least a portion of the bypass body cavity, and through the other of the MC passage and the brake-side passage; and wherein the bypass plunger selectively engages the bypass valve seat to substantially cover the bypass valve fluid path in response to energization of the bypass armature, thereby moving the bypass plunger toward the second body end. [16] A braking system according to claim 15, wherein the MC passage is in indirect flow communication with the corresponding first or second MC output via a corresponding first or second traction control isovalve and the brake-side passage is in direct flow communication with the corresponding front wheel brake. [17] The braking system of claim 15, comprising a bypass biasing spring mechanically disposed between the bypass plunger and at least a portion of the bypass valve body in the bypass body cavity, the bypass biasing spring operable to bias the bypass plunger toward the first body end. [18] A braking system according to claim 1, wherein the pump inlet damper comprises: a PIA piston having a piston head and a piston skirt, wherein the piston shaft has at least one rib extending longitudinally therealong, wherein the PIA piston is hydraulically arranged between the pump pistons and a surrounding space outside the braking system, a PIA piston chamber circumferentially surrounding the piston head; a PIA seal arranged laterally between the piston head and an inner wall of the PIA piston chamber, the PIA seal dividing the PIA piston chamber into a wet and a dry chamber region, which are spaced apart from each other in the longitudinal direction, with the drying chamber area being in flow connection with the surrounding space outside the braking system; and a PIA spring that biases the PIA piston toward the drying chamber area; wherein the PIA piston moves longitudinally toward the pump pistons in response to the application of a first predetermined level of negative pressure from the pump pistons, and the PIA piston moves longitudinally away from the pump pistons in response to a biasing force from the PIA spring and / or a second predetermined level of negative pressure, the second predetermined level of negative pressure being less than the first predetermined level of negative pressure, from the pump pistons and / or a predetermined level of positive pressure from the pump pistons. [19] The braking system of claim 1, wherein the pump inlet damper is a single pump inlet damper. [20] The braking system of claim 1, wherein the motor-driven master cylinder comprises an MC drive electric motor, a primary MC chamber, a secondary MC chamber, a primary MC piston configured for selective longitudinal movement within the primary MC chamber in response to longitudinal movement imparted by a ball nut assembly along a ball nut axis, and a secondary MC piston configured for selective longitudinal movement within the primary and / or secondary MC chamber in response to longitudinal movement imparted by the ball nut assembly along the ball nut axis, and wherein the MC drive motor rotates a drive shaft having a drive shaft axis substantially parallel to the ball nut axis, and wherein a rotary movement of the drive shaft is converted into a rotary movement of a spindle of the ball nut arrangement via an MC gear set.

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