Patent ID: 12227159

DESCRIPTION OF ASPECTS OF THE DISCLOSURE

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which the present disclosure pertains.

The invention comprises, consists of, or consists essentially of the following features, in any combination.

FIG.1depicts a fluid separator100configured for inclusion in a brake system having normal non-failure and backup braking modes. The fluid separator100includes a separator housing102defining a longitudinal bore104having first and second longitudinally separated bore ends106and108, respectively. The “longitudinal” direction, as used herein, is substantially parallel to arrow “L”, which is substantially in the horizontal direction, in the orientation ofFIG.1.

Components of the brake system, including the fluid separator100, may be housed in one or more blocks or housings. The block or housing may be made from solid material, such as aluminum, that has been drilled, machined, or otherwise formed to house the various components. Fluid conduits may also be formed in the block or housing, between two or more components or between a component and a “port” for attachment to a structure outside the block or housing. Accordingly, the separator housing102may comprise a portion of a block or housing that defines and/or at least partially encloses one or more other components of a brake system, as discussed below.

A first fluid passage110is in fluid communication with the bore104at the first bore end106. A second fluid passage112is in fluid communication with the bore104adjacent the second bore end108. A third fluid passage114is in fluid communication with a portion of the bore104spaced apart from both the first and second bore ends106and108. The third fluid passage114includes an annular fluid groove114A defined in the bore104circumferentially around the piston118.

At least one of the first, second, and third fluid passages110,112,114may include an inline filter (shown schematically at116inFIGS.1-2, with like symbols to the116-labeled “diamonds” inFIG.2representing appropriate filters throughout the Figures).

It is noted that the fluid separator100, when supplying fluid to a wheel brake, may be mounted in a corresponding brake system (via the separator housing102) such that the third fluid passage114(which is most directly fluidly connected to the wheel brake) is at a higher elevation than the remaining parts of the fluid separator100. As a result, hydraulic fluid is prevented from draining out of the brake system through the third fluid passage114if, for example, the connected power transmission unit has a failure that result in loss of hydraulic fluid.

The first and third fluid passages110and114may intersect with the bore104in at least one of a longitudinal and a lateral relationship thereto, as shown inFIG.1. The “lateral” direction, as referenced herein, is substantially perpendicular to the longitudinal direction (i.e., within a vertical plane extending into and out of the plane of the page), in the orientation ofFIG.1. The second fluid passage112, however, may intersect with the bore104at an angle to the longitudinal direction L which is not parallel or perpendicular thereto, also as shown inFIG.1. For example, the second fluid passage112may intersect with the bore104at an oblique or acute angle to the longitudinal direction L as shown inFIG.1. It is contemplated, though, that any of the first through third fluid passages110,112,114can intersect with the bore104at any suitable parallel, perpendicular, or other angle as desired for a particular use application of the fluid separator100, and for any reason such as, but not limited to, fitting into a particular space and/or aligning with another component of a particular brake system.

A free-floating piston118is located inside the bore104and is configured for longitudinal movement with respect to the bore104responsive to fluid pressure within the bore104. “Free-floating” is used herein to indicate that the piston118is not tied to an external rod or other component extending outside the longitudinal bore104, but the piston118instead moves back and forth within the bore104responsive to local fluid pressure influences within the bore104. A biasing spring120(shown in schematic cross-section inFIG.1) urges the piston118toward the second bore end108.

As shown inFIG.1, the piston118may be of a cup-type including an internal piston cavity122configured to receive a portion of the biasing spring122therewithin. The piston118includes a skirt area124substantially laterally surrounding a circumference of the biasing spring122. The skirt area124includes a plurality of piston bores126extending substantially laterally through the body of the piston118. The piston bores126are configured to selectively place an interior portion of the skirt area124in fluid communication therethrough with the third fluid passage114, responsive to a longitudinal position of the piston118within the bore104.

That is, when the piston118is in the leftmost position shown inFIG.1, a small annular gap (circled at128inFIG.1) facilitates passage of hydraulic fluid from the portion of the bore104adjacent the first bore end106, through the piston bores126, through the annular gap128, into the annular fluid groove114A of the third fluid passage114, and through the unidirectionally extending portion of the third fluid passage114. More broadly, when the brake system is in the normal non-failure braking mode, the piston118is located within the bore104in such a way that a primary fluid route is defined between the first and third fluid passages110and114through at least a portion of a body of the piston118—as shown, through the piston bores126. Fluid in the primary fluid route, stated otherwise, passes through at least one piston bore126and through the annular fluid groove114A under fluid pressure from a chosen one of the first and third fluid passages110,114, with that choice depending on the flow direction desired.

Conversely, when the piston118moves toward the right (in the orientation ofFIG.1), the piston bores126are moved out of fluid communication with the annular fluid groove114A of the third fluid passage114(thus closing the annular gap128), and further rightward motion of the piston118pressurizes the fluid inside the bore104and the internal piston cavity122to force fluid out the first fluid passage110. That is, when the brake system is in the backup braking mode, the piston118is urged toward the first bore end106(i.e., rightward, in the orientation ofFIG.1) by fluid pressure from the second fluid passage112to at least partially close the primary fluid route (by moving the piston bores126out of fluid communication with the annular fluid groove114A). Accordingly, travel of the piston118toward the first bore end106is operative to raise fluid pressure within the bore104adjacent the first fluid passage110and urge fluid out of the bore104through the first fluid passage110.

An end cap130is located at the second bore end112to prevent egress of fluid from the bore104to an ambient space outside the separator housing102. The end cap130is maintained on the separator housing102via at least two retainers of any suitable type, with the retainers shown generally at132. For example, and as shown in the embodiment ofFIG.1, a first retainer may be a clinch of the end cap130into engagement with the separator housing102, and a second retainer may be a retention ring134(e.g., a wire ring or snap ring) extending substantially about a circumference of the end cap130(either around a body of the end cap130or “outboardly” adjacent the end cap130) to maintain the end cap130in a predetermined relationship with the separator housing. Fasteners, welds, adhesives, threaded retention interface, staked retention interface, any other type of retainer, or any combination thereof could be used as retainers132; one of ordinary skill in the art can provide one or more suitable retainers132to a fluid separator100for a particular use environment.

A piston face136of the piston118is located longitudinally adjacent the end cap130and in fluid communication with the second fluid passage112. Fluid pressure from the second fluid passage112against the piston face136selectively urges the piston118toward the first bore end106(rightward, in the orientation ofFIG.1) against a spring force of the biasing spring120. In this manner, the fluid separator100can be used to direct and supply pressurized hydraulic fluid to any desired brake(s) of the brake system, in either a normal non-failure mode or a backup braking mode, as will be described in detail below.

The piston face136may include at least one standoff protrusion138configured for selective contact with the end cap130to maintain longitudinal spacing of at least an other portion of the piston face136relative to the end cap130. As shown inFIG.1, the dark-shaded standoff protrusions138prevent the entire piston face136from butting up flush with the end cap130, which could undesirably result in “hydraulic lock” of the piston118, thus preventing piston118movement, under certain conditions.

The bore104may define a first seal groove140longitudinally interposed between the third fluid passage114and the first bore end106. The first seal groove140, when present, may be configured to selectively receive a lip seal142thereinto. The lip seal142engages with an outer surface of the piston118to resist fluid communication from the first fluid passage110to the third fluid passage114around the outer portion of the skirt area124of the piston118, such as when the piston118has moved rightwardly enough to take the piston bores126out of fluid communication with the third fluid passage114. However, due to the directional shape of the lip seal142, a predetermined amount of fluid “seepage” from the third fluid passage114toward the first fluid passage110may be permitted by the lip seal142, such as when a residual or limited amount of fluid is supplied to the third fluid passage114in the backup braking mode. The lip seal142may provide a “check valve” function to help avoid lockup and balance the side-port pressure of the fluid separator100. It should be noted, however, that the lip seal142type check valve function is contemplated for use mainly (though not exclusively) when the fluid separator100itself has a failure that prevents the piston118from returning to the “normal non-failure” operational mode (the leftmost position, as shown inFIG.1).

The bore104may also or instead define a second seal groove144longitudinally interposed between the third fluid passage114and the second bore end108. The second seal groove144, when present, is configured to selectively receive a bidirectional seal146thereinto. The bidirectional seal146engages with an outer surface of the piston118to resist fluid communication in either direction between the first and second bore ends106and108.

The bore104may include at least one longitudinally extending relief slot148in a wall of the bore104, the relief slot being interposed between the first and third fluid passages110and114. When present, the relief slot148may permit fluid flow therethrough when at least a portion of the piston118is laterally adjacent the relief slot148within the bore104. Indeed, a secondary fluid route may be defined from the third fluid passage114, through the relief slot148, and to the first fluid passage110when at least a portion of the piston118is laterally adjacent the relief slot148within the bore104. The relief slot148, when present, allows fluid to move past the piston118when the piston118moves toward the right, in the orientation ofFIG.1.

When the fluid separator100is in a “passive” or “non-powered” mode during a normal non-failure braking mode, the biasing spring120pushes the free-floating piston118toward the second bore end108(leftward, in the orientation ofFIG.1), to allow pressurized hydraulic fluid to flow, for example, from a pressurized fluid source into the third fluid passage114, along the primary fluid route through the annular gap128and through the piston bores126, through the bore104and out the first fluid passage110, to hydraulically actuate a wheel brake in fluid communication with the first fluid passage110. Then, at a desired time (such as during a backup braking mode after a failure of some component), pressurized hydraulic fluid is supplied (e.g., from a different pressurized fluid source) into the second fluid passage110, which pushes against the piston face136and overcomes the force of the biasing spring120to place the fluid separator100into an active or powered mode. When the piston118moves a predetermined distance toward the first bore end106(rightward, in the orientation ofFIG.1), the piston bores126are taken out of fluid communication with the third fluid passage114, thus “shutting off” the primary fluid route. Further motion of the piston118toward the first fluid passage110then pushes hydraulic fluid already in the bore104adjacent the first bore end106under pressure and into the first fluid passage110, to facilitate selective application of the wheel brake using pressure developed within the bore104via movement of the piston118. As a result, the second fluid passage112can be used to facilitate operation of the attached wheel brake in a backup braking mode.

FIG.2depicts a brake system150which uses at least one fluid separator100ofFIG.1. The brake system150is similar in concept to the brake system shown in FIG. 7 of copending U.S. patent application Ser. No. 17/188,288, filed 1 Mar. 2021 and titled “Apparatus and Method for Control of a Hydraulic Brake System” (hereafter referenced as “the '288 application”), the entire contents of which are incorporated herein by reference. The brake system150is shown inFIG.2as a hydraulic brake by wire system in which electronically controlled fluid pressure is utilized to apply braking forces for at least a portion of the brake system150. The brake system150may suitably be used on a ground vehicle, such as an automotive vehicle having four wheels with a wheel brake associated with each wheel. Furthermore, the brake system150can be provided with other braking functions such as anti-lock braking (ABS) and other slip control features to effectively brake the vehicle. Components of the brake system150may be housed in one or more blocks or housings. The block or housing may be made from solid material, such as aluminum, that has been drilled, machined, or otherwise formed to house the various components. Fluid conduits may also be formed in the block or housing.

The brake system150shown inFIG.2is provided for selectively actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes of a vehicle. A selected pair of the front wheel brakes and the rear wheel brakes is hydraulically actuated and an other pair of the front wheel brakes and the rear wheel brakes is electrically actuated. As shown inFIG.2, the right rear wheel brake152A and left rear wheel brake152C are electrically actuated, and the left front wheel brake152B and right front wheel brake152D are hydraulically actuated. The brake system150has normal non-failure and backup braking modes. The brake system150has a reservoir154for storing hydraulic fluid and a deceleration signal transmitter156.

The deceleration signal transmitter156includes a brake pedal158connected to a brake pedal unit160and selectively actuated by a driver of the vehicle to indicate a desired braking command. The brake pedal unit160has at least one brake sensor162(multiples shown at “T” in the Figures, for redundancy) for determining a position of the brake pedal158and responsively producing a braking signal corresponding to the desired braking command. The deceleration signal transmitter156is hydraulically isolated from at least the reservoir110and first and second power transmission units108A and108B of the depicted brake system100.

The brake system150also includes at least one electronic control unit (“ECU”)164(two shown). Each ECU164A,164B may include microprocessors and other electrical circuitry, and may be connected to either a dedicated or a shared (with the other ECU) power supply. Each ECU164A,164B receives various signals, processes signals, and controls the operation of various electrical components of the brake system150in response to the received signals. Each ECU164A,164B can be connected to various sensors of the brake system150such as reservoir fluid level sensors, pressure sensors (shown schematically at “P” in the Figures), travel sensors, switches, wheel speed sensors, and/or steering angle sensors. Each ECU164A,164B may also be connected to an external module (not shown) for receiving information related to yaw rate, lateral acceleration, longitudinal acceleration of the vehicle, or other characteristics of vehicle operation for any reason, such as, but not limited to, controlling the brake system150during vehicle braking, stability operation, or other modes of operation. Additionally, each ECU164A,164B may be connected to the instrument cluster for collecting and supplying 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.

The brake system150ofFIG.2is of the “diagonal split” type, wherein a first brake pressure circuit (schematically shown by dashed line “A”) provides hydraulic power and control to the left front wheel brake152B, and electric power and control to the right rear wheel brake102C (which is of a wholly electric type). Likewise, the second brake pressure circuit (schematically shown by dashed line “B”) provides hydraulic power and control to the right front wheel brake152A and electric power and control to the left rear wheel brake152B. A pair of brake motors166A,166C are provided for electrically actuating respective left and right rear wheel brakes152A,152C.

A first power transmission unit168is in fluid communication with the reservoir154, a selected one of the hydraulically actuated wheel brakes (one of the front brakes152B,152D in the brake system150ofFIG.2), and a second fluid separator100B corresponding to an other one of the hydraulically actuated wheel brakes (the other of the front brakes152B,152D in the brake system150ofFIG.2). The first power transmission unit168is configured to selectively generate pressurized hydraulic fluid for actuating the selected one of the hydraulically actuated wheel brakes152B,152D during a normal non-failure braking mode and the other one of the hydraulically actuated wheel brakes152B,152D, via the second fluid separator100, during a backup braking mode as mentioned previously.

The first electronic control unit164A is configured to control the first power transmission unit168A and a selected one of the electrically actuated wheel brakes152A,152C, on a contralateral side of the vehicle from the selected one of the hydraulically actuated wheel brakes152B,152D which is actuated by the first power transmission unit164A in the normal non-failure braking mode. For example, and as shown inFIG.2, the first electronic control unit164A may hydraulically control the left front wheel brake152B (via the first power transmission unit164A) and electrically control the right rear wheel brake152A. Through such a “diagonal” system, failure of the first power transmission unit164A is less likely to result in loss of both brakes on a single side of the vehicle.

The second power transmission unit168B is in fluid communication with the reservoir154, the other one of the hydraulically actuated wheel brakes152B,152D (that is, the other one from that which is actuated in normal non-failure mode by the first power transmission unit168A via the first power transmission unit168A), and a first fluid separator100A corresponding to the selected one of the hydraulically actuated wheel brakes152B,152D (that is, the one which is actuated in normal non-failure mode by the first power transmission unit168A via the first power transmission unit168A). The second power transmission unit168B is configured to selectively generate pressurized hydraulic fluid for actuating the other one of the hydraulically actuated wheel brakes (152D, as shown inFIG.2) during a normal non-failure braking mode and the selected one of the hydraulically actuated wheel brakes (152B, as shown inFIG.2), via the first fluid separator100A, during a backup braking mode.

The second electronic control unit164B is configured to control the second power transmission unit168B and a selected one of the electrically actuated wheel brakes152A,152C, on a contralateral side of the vehicle from the other one of the hydraulically actuated wheel brakes152B,152D which is actuated by the second power transmission unit164B in the normal non-failure braking mode. For example, and as shown inFIG.2, the second electronic control unit164B may hydraulically control the right front wheel brake152D (via the second power transmission unit164B) and electrically control the left rear wheel brake152C. Through such a “diagonal” system, failure of the second power transmission unit168B is less likely to result in loss of both brakes on a single side of the vehicle.

At least one of the first and second power transmission units168A,168B may include a single acting plunger unit configured to selectively generate the pressurized hydraulic fluid for actuating a corresponding hydraulically actuated wheel brake152B,152D. At least one of the first and second power transmission units168A,168B could also or instead include a dual acting plunger unit, a ball screw unit, a pulley-motor unit, a rack-and-pinion unit, and/or any other desired component for selectively generating pressurized hydraulic fluid for a particular use environment.

Stated differently, each electrically powered brake includes a rear brake motor166A,166C which is controlled by a corresponding one of the first and second electronic control units164A,164B that controls the contralateral front wheel brake152B,152D. It should be noted that, whenever a wheel brake152is shown or described herein as being only electrically powered, or as not having a hydraulic connection to other hydraulic components of the brake system150, that wheel brake152will be of an electro-mechanical type, whether or not an electrical brake (not shown) is provided to any other wheels of the same brake system150.

A control valve170A,170B is provided to each of the first and second brake pressure circuits, and is hydraulically interposed between the reservoir154and a respective first or second power transmission unit168A or168B. It is contemplated that the first power transmission unit168A and the first control valve170A may be packaged together, and spaced apart from, the second power transmission unit168B and the second control valve170B—which may, likewise, be packaged together. This differential placement may be provided for any reason, such as, but not limited to, space or weight savings, packaging flexibility, and ease of manufacture. The control valves170A,170B, when present, may be venting valves which are normally de-energized, but then energized closed during a normal non-failure braking action.

First and second backup valves172A,172B are provided to each of the first and second brake pressure circuits, respectively, and are hydraulically interposed between a respective first or second power transmission unit168A or168B and a second fluid passage112of a respective second or first fluid separator100B,100A. The first and second backup valves172A,172B may be left de-energized (in a normally-open condition) when sensed pressure in the brake system150is within a predetermined normal pressure range (indicating a normal non-failure braking mode). When sensed pressure at a predetermined location in the brake system150is outside a normal range, at least one of the first and second backup valves172A,172B may be left open (de-energized) so that both front brakes152B,152D can still be applied. At least one of the first and second backup valves172A,172B is configured to selectively provide hydraulic fluid through the second fluid passage112of the respective fluid separator100A,100B to control sensed pressure to a predetermined slip control level.

When hydraulic fluid is provided, from any desired source, through the second fluid passage112of the respective fluid separator100A,100B the piston118of the fluid separator is pushed by pressure from the hydraulic fluid away from the second bore end108by overcoming the biasing spring120force. This movement of the piston118will pressurize the first fluid passage110and the attached hydraulically actuated wheel brake152B,152D in a backup mode, as previously discussed. Through use of the depicted arrangement of components, it is contemplated that three of the wheel brakes will still be available even in the backup braking mode following failure of one of the power transmission units168and/or its corresponding electronic control unit164.

The braking signal from the deceleration signal transmitter156is transmitted, in a wired or wireless manner, to at least one of the first and second electronic control units164A,164B. At least one of the first and second electronic control units164A,164B controls at least one of a respective power transmission unit168A,168B, a respective fluid separator100A,100B, and a respective one of the electrically actuated wheel brakes152A,152C (via brake motor166A,166C) responsive to the braking signal.

With reference now toFIG.3, a second configuration of the brake system150is depicted, parts or all of which can be used with other components of the present invention, as desired. Description of similar components and operation which is made elsewhere in this application will not necessarily be repeated for each and every described configuration or aspect of the brake system150, for brevity, but should instead be considered to apply to like-numbered portions of other configurations as appropriate.

The brake system150ofFIG.3is similar in concept to the brake system shown in FIG. 8 of the '288 application, with the addition of first and second fluid separators100A,100B, for operation as described elsewhere herein. The brake system150ofFIG.3is configured to provide independent pressure control of the front brakes152B,152D even after a failure of at least one power transmission unit168A,168B, in a multiplexed manner.

The brake system150ofFIG.3therefore includes multiplexed control of the hydraulically actuated pair of wheel brakes152B,152D, similar to the multiplexed control disclosed in the '288 application. A first multiplex control valve arrangement174B is interposed hydraulically between the first power transmission unit168A and the first fluid separator100A. A second multiplex control valve arrangement174D is interposed hydraulically between the second power transmission unit168B and the second fluid separator100B. The first and second multiplex control valve arrangements174B,174D each are controlled by a corresponding first or second electronic control unit164A or164B. The first and second multiplex control valve arrangements174B,174D each include respective first and second multiplex valves176and178, respectively. Combined with the first and second multiplex control valve arrangements174B,174D in certain configurations of the brake system150, desirable spike apply response and slip control modulation properties could be achieved through use of the components shown and described herein, and may readily be provided by one of ordinary skill in the art for a particular use environment of the brake system150.

With reference now toFIG.4, a third configuration of the brake system150is depicted, parts or all of which can be used with other components of the present invention, as desired. Description of similar components and operation which is made elsewhere in this application will not necessarily be repeated for each and every described configuration or aspect of the brake system150, for brevity, but should instead be considered to apply to like-numbered portions of other configurations as appropriate.

The brake system150ofFIG.4is similar in concept to the brake system shown in FIG. 2 of the '288 application, with the addition of first and second fluid separators100A,100B, for operation as described elsewhere herein. In the brake system150ofFIG.4, braking at all four wheels can be maintained after failure of one power transmission unit168A,168B. Although the fluid separators100A,100B ofFIG.4are shown as packaged in a separate “block” (dashed line) from the first and second brake pressure circuits A and B, it is contemplated that one or more of the fluid separators100A,100B could instead be co-located with and/or integrated into a corresponding first or second brake pressure circuit A or B, as desired.

In the brake system150shown inFIG.4, a selected pair of the front wheel brakes and the rear wheel brakes is hydraulically actuated (here, the front wheel brakes152B,152D) and an other pair of the front wheel brakes and the rear wheel brakes is selectively electrically and/or hydraulically actuated (here, the rear wheel brakes152A,152C). The rear brake motors166A,166C will be used to provide a backup and/or parking brake feature in many use environments of the brake system150, with the rear wheel brakes152A,152C being used in a hydraulically operated mode as service brakes. For redundancy in the backup braking mode, the brake motor166for a selected electrically and/or hydraulically actuated brake152may be controlled by the contralateral electronic control unit164from that which controls the hydraulic fluid to the same brake152during normal non-failure operation. As is shown inFIG.4, the rear wheel brakes152A,152C have electric backup and thus are not also provided with fluid separator100backup (from the contralateral power transmission unit168), though it is contemplated that fluid separators (not shown), and the attendant backup function, could be provided to the electrically and/or hydraulically actuated brakes152, as well.

As shown inFIG.4, a first EH multiplex control valve arrangement180A is interposed hydraulically between the first power transmission unit168A and a selected one (here, right rear wheel brake152A) of the selectively electrically and/or hydraulically actuated wheel brakes. The first electronic control unit164A is configured to control the first power transmission unit168A, the first multiplex control valve arrangement174B (corresponding to the left front wheel brake152B), and the first EH multiplex control valve arrangement180A, responsive to a brake signal from the deceleration signal transmitter156.

Also as shown inFIG.4, a second EH multiplex control valve arrangement180C is interposed hydraulically between the second power transmission unit168B and an other one (here, left rear wheel brake152C) of the selectively electrically and/or hydraulically actuated wheel brakes. The second electronic control unit164B is configured to control the second power transmission unit168B, the second multiplex control valve arrangement174D (corresponding to the right front wheel brake152D), and the second EH multiplex control valve arrangement180C, responsive to a brake signal from the deceleration signal transmitter156. The first and second EH multiplex control valve arrangements180A,180C each include respective first and second multiplex valves176and178.

It is contemplated that, for arrangements of a brake system150in which multiplex control of the selectively electrically and/or hydraulically actuated wheel brakes152is not desired, one of ordinary skill in the art could provide a suitable “straight” hydraulic arrangement to facilitate transfer from a power transmission unit168to a respective selectively electrically and/or hydraulically actuated wheel brake152, for a particular use environment.

With reference now toFIG.5, a fourth configuration of the brake system150is depicted, parts or all of which can be used with other components of the present invention, as desired. Description of similar components and operation which is made elsewhere in this application will not necessarily be repeated for each and every described configuration or aspect of the brake system150, for brevity, but should instead be considered to apply to like-numbered portions of other configurations as appropriate.

The brake system150ofFIG.5is similar in concept to the “diagonal split” brake system shown inFIG.4and discussed above, but rearranged into a “vertical split” such that the first power transmission unit168A provides (multiplexed) hydraulic fluid to both of the front brakes152B,152D in a normal non-failure braking mode, and the second power transmission unit168B provides (multiplexed) hydraulic fluid to both of the rear brakes152A,152C in a normal non-failure braking mode. In case of failure of the first power transmission unit168A (or other lack of hydraulic fluid through the multiplex control valve arrangements174B,174D), then the backup valves172A,172B will be actuated to permit hydraulic fluid flow in the backup braking mode from the second power transmission unit168B to the front brakes152B,152D via the fluid separators100A,100B. Should the second power transmission unit168B (or other related components) fail and cease to provide pressurized hydraulic fluid to the rear brakes152A,152C, then the rear brake motors166A,166C may be actuated by one or both of the first and second electronic control units164A,164B to provide braking force electro-mechanically to the rear brakes152A,152C. In many use environments of the brake system150ofFIG.5, the rear brake motors166A,166C will be controlled by the same one of the first and second electronic control units1564A,164B that controls the first power transmission unit168A corresponding to the front brakes152B,152D, for backup purposes.

Turning toFIG.6, a fifth configuration of the brake system150is depicted, parts or all of which can be used with other components of the present invention, as desired. Description of similar components and operation which is made elsewhere in this application will not necessarily be repeated for each and every described configuration or aspect of the brake system150, for brevity, but should instead be considered to apply to like-numbered portions of other configurations as appropriate.

The brake system150ofFIG.6includes similar components and arrangements to those of copending U.S. patent application Ser. No. 17/188,363, filed 1 Mar. 2021 and titled “Apparatus and Method for Control of a Hydraulic Brake System” and to copending U.S. patent application Ser. No. 17/400,178, filed concurrently herewith and titled “Brake System with Plunger-Based Secondary Brake Module”, the entire contents of both of which are incorporated herein by reference.

InFIG.6, a manual pushthrough type brake system150is provided for hydraulically actuating a pair of front wheel brakes. The brake system150has normal non-failure and backup braking modes. Unlike the brake systems150ofFIGS.2-5, the brake system150ofFIG.6does not include electrically actuated motors, but instead has iso/dump type hydraulic control of both the pair of front brakes and the pair of rear brakes152.

In the illustrated embodiment of the brake system150ofFIG.6, there are four wheel brakes152A,152B,152C, and152D. The wheel brakes152A,152B,152C, and152D can have any suitable wheel brake structure operated by the application of pressurized brake fluid. Each of the wheel brakes152A,152B,152C, and152D may include, for example, a brake caliper mounted on the vehicle to engage a frictional element (such as a brake disc) that rotates with a vehicle wheel to effect braking of the associated vehicle wheel. The wheel brakes152A,152B,152C, and152D can be associated with any combination of front and rear wheels of the vehicle in which the brake system150is installed. For example, the brake system150may be configured as a front/rear or “vertical split” system, as shown, such that the first power transmission unit168A is configured for selectively providing pressurized hydraulic fluid for actuating at least a selected one of the pair of front wheel brakes152B and152D, in a non-failure normal braking mode, as will be discussed below.

The second power transmission unit168B is configured for selectively providing pressurized hydraulic fluid for actuating a chosen pair of brakes152(here, the pair of front wheel brakes152B and152D) via the first and second fluid separators100A,100B, when the brake system150is in a backup braking mode, and the other pair of brakes152(here, the rear wheel brakes152A and152C), when the brake system150is in a normal non-failure braking mode. A second reservoir154B is provided to supply hydraulic fluid to the second power transmission unit168B. The first electronic control unit164A controls at least one of the first and second power transmission units. A second electronic control unit164B may be provided. When the second electronic control unit164B is present, and as will be presumed in the below description ofFIG.6, the first electronic control unit164A controls the first power transmission unit168A, and the second electronic control unit164B controls the second power transmission unit168B.

As shown in all of the Figures, the wheel brake152A may be associated with a right rear wheel of the vehicle in which the brake system150is installed, and the wheel brake152B may be associated with the left front wheel. The wheel brake152C may be associated with the left rear wheel, and the wheel brake152D may be associated with the right front wheel.

The brake system150also includes a brake pedal unit, indicated generally at160, a pedal simulator, indicated generally at182, and the aforementioned first and second reservoirs154A,154B.

The reservoirs154A,154B store and hold hydraulic fluid for the brake system150. The fluid within the first and second reservoirs154A,154B is preferably held at or about atmospheric pressure, but the fluid may be stored at other pressures if desired. The first and second reservoirs154A,154B are shown schematically as each having three tanks or sections with fluid conduit lines connected thereto. The sections can be separated by several interior walls within the first and second reservoirs154A,154B and are provided to prevent complete drainage of first and second reservoirs154A,154B in case one of the sections is depleted due to a leakage via one of the three lines connected to the first and second reservoirs154A,154B. Alternatively, the first and second reservoirs154A,154B may include multiple separate housings. The first and second reservoirs154A,154B may each include at least one fluid level sensor184(two shown on each reservoir, for redundancy) for detecting the fluid level of one or more of the sections of the first and second reservoirs154A,154B.

The first and second power transmission units168A,168B of the brake system150function as a source of pressure to provide a desired pressure level to respective ones of the hydraulically operated wheel brakes152A,152B,152C, and152D during a typical or normal brake apply. After a brake apply, fluid from the wheel brakes152A,152B,152C, and152D may be returned to the respective power transmission unit168A or168B and/or be diverted to the respective reservoir154A,154B. InFIG.6, the first and second power transmission units168A,168B are shown as being dual acting plunger type power transmission unit, though single acting plunger or any other desired type of controllable hydraulic fluid pressurizer could be also or instead provided to the brake system150. It is also contemplated that other configurations (not shown) of the brake system150could include hydraulic control of just a selected one of the pair of front wheel brakes152B,152D and the pair of rear wheel brakes152A,152C (with the other pair being electrically controlled/actuated). One of ordinary skill in the art would be readily able to provide such an arrangement for a desired use environment, following aspects of the present invention.

The second power transmission unit168B of the brake system150functions as a source of pressure to provide a desired pressure level to the pair of front wheel brakes152B and152D in a backup or “failed” situation, when, for some reason, the first power transmission unit168A is unable to provide fluid to those selected wheel brakes.

As shown schematically inFIG.6, the brake pedal unit160includes a master cylinder186with a housing188defining a longitudinally extending bore for slidably receiving various cylindrical pistons and other components therein. Examples of such components are the first and second springs longitudinally extending in series within the bore, as shown in the Figures. Note that the housing188is not specifically schematically shown in the Figures, but instead the walls of the longitudinally extending bore are schematically illustrated. The housing188may be formed as a single unit or include two or more separately formed portions coupled together. For some use environments, the master cylinder186may be of a tandem master cylinder type.

An MC primary piston190is connected with a brake pedal158via a linkage arm192. Leftward movement of the MC primary piston190may cause, under certain conditions, a pressure increase within the master cylinder186.

The pedal simulator182is in selective fluid communication with the master cylinder186for providing predetermined brake pedal response. As shown, the pedal simulator182is connected to the master cylinder186via one or more hydraulic passages, but it is contemplated that the “selective fluid communication” could be provided via integration of the pedal simulator182into the master cylinder186.

The brake system150may further include an optional solenoid actuated simulator test valve194which may be electronically controlled between an open position and a powered closed position and be located fluidly between the first reservoir154A and the master cylinder186.

The brake pedal unit160is connected to the brake pedal158and is actuated by the driver of the vehicle as the driver presses on the brake pedal158. A brake sensor or switch may be electrically connected to the ECUs164A,164B to provide a brake signal indicating a depression of the brake pedal158. That is, the master cylinder186is operable to provide a brake signal responsive to actuation of the brake pedal158connected thereto.

The brake pedal unit160may be used as a back-up source of pressurized fluid to essentially replace the normally supplied source of pressurized fluid from the first power transmission unit168A under certain failed conditions of the brake system150, and/or upon initial startup of the brake system150. This situation is referred to as a manual push-through event, or a “manual apply”.

In such a push-through mode, the brake pedal unit160can supply pressurized fluid to a master cylinder output196(including dual fluid passages in the embodiment ofFIG.6), which is then routed to the front wheel brakes152B,152D as desired. This flow is pushed through, largely under mechanical pressure upon the brake pedal158from the driver's foot, from the master cylinder186. That is, the master cylinder186is selectively operable during a manual push-through mode by actuation of the brake pedal158connected to the master cylinder186to generate brake actuating pressure at a master cylinder output196for hydraulically actuating at least one of the pair of front wheel brakes152B,152D and the pair of rear wheel brakes152A,102C (hydraulically actuating the pair of front wheel brakes152B,152D, as shown inFIG.6

In summary, the master cylinder186is fluidly connected to the first reservoir154A and is operable to provide a brake signal responsive to actuation of a brake pedal158connected thereto. The first power transmission unit168A is in fluid communication with the master cylinder186and the first reservoir154A. The second power transmission unit168B is in fluid communication with the second reservoir154B.

First and second two-position three-way valves198B and198D, respectively, are provided to the brake system150as shown in theFIG.6. Each of the first and second three-way valves198B and198D is hydraulically connected with the master cylinder186, the first power transmission unit168A, and a corresponding wheel brake152of the pair of wheel brakes actuated by the first power transmission unit168A in the normal non-failure mode. The first and second three-way valves198B and198D selectively control hydraulic fluid flow from a chosen one of the master cylinder186and the first power transmission unit168A to the corresponding front wheel brakes152B and152D. Through use of the first and second three-way valves198B and198D, hydraulic fluid can be routed to the corresponding wheel brakes152B,152D in a desired manner (from either the master cylinder186or the first power transmission unit168A) to assist with boosted braking control and provide desired response times and efficient pressure flow to the respective wheel brakes152associated with each three-way valve.

FIG.6also depicts a replenishing check valve200, which is located fluidically between the first reservoir154A and the first power transmission unit168A. When present, the replenishing check valve200may be provided to assist with refilling of the first power transmission unit168A (or components thereof) under predetermined conditions. For example, the replenishing check valve200may help to facilitate refilling of the chamber in front of the DAP head when a DAP-type first power transmission unit168A is building pressure during its retraction stroke by pushing fluid out of the annular chamber behind the DAP head. This is done, for example, during slip control if additional flow to the brakes is needed after the DAP is stroked fully forward. Another replenishing check valve200is likewise associated with the second power transmission unit168B, for similar operation.

A normally closed dual-acting plunger (“DAP”) valve202and a normally open DAP valve204are interposed hydraulically between the primary power transmission unit104and at least one of the first and second three-way valves198B and198D. Additional normally closed and normally open DAP valves are likewise associated with the second power transmission unit168B, for similar operation.

Fluid control of each of the pairs of front and rear wheel brakes152B,152D and152A,152C may be provided by an arrangement of iso and dump valves206and208, referenced collectively as ABS modulator arrangements210.

Here, for clarity inFIG.6, the iso and dump valves206and208are appended with the letter “B” or “D”, referencing a respective front wheel brake152B and152D, or the letter “A” or “C”, referencing a respective rear wheel brake152A and152C, with which the so-labeled valves are respectively associated. A chosen one of the iso and dump valves206and208receives input from an output of the other one of the iso and dump valves206and208.

The iso/dump type fluid control facilitated by the ABS modulator arrangement210selectively provides, for example, slip control or traction compensation to at least one of the wheel brakes152. In summary, at least a portion of the ABS modulator arrangement210for each wheel brake152is hydraulically interposed between at least one of the first and second three-way valves198and at least a selected wheel brake152of the pair of front wheel brakes152B,152D and the pair of rear wheel brakes152A,152C.

With reference now to the right “half” ofFIG.2, and the portions of the brake system drawing fluid from the second reservoir154B, third and fourth two-position three-way valves198A and198C are each hydraulically connected with the second reservoir154B, the second power transmission unit168B, and a corresponding brake152A,152C of the other one of the pair of front wheel brakes and the pair of rear wheel brakes. The third and fourth three-way valves198A and198C selectively control hydraulic fluid flow from a chosen one of the second reservoir154B and the second power transmission unit168B to the corresponding brake152A or152C of the other one of the pair of front wheel brakes and the pair of rear wheel brakes (that is, the “other pair” which is not actuated during normal non-failure braking by fluid flowing through the first and second three-way valves198B and198D. It should be noted that, due to the absence of a master cylinder186and/or brake pedal unit160associated directly with the second power transmission unit168B, manual push-through is not provided in the brake system150ofFIG.6for the pair of rear wheel brakes152A and152C.

An ABS modulator arrangement210A,201C is hydraulically interposed between each of the third and fourth three-way valves198A,198C and the corresponding brake (here, rear brakes152A,152C) of the other one of the pair of front wheel brakes and the pair of rear wheel brakes. The ABS modulator arrangements210A,210C associated with the second power transmission unit168B operate analogously to the ABS modulator arrangements210B,210D associated with the first power transmission unit168A, for their corresponding wheel brakes152.

The brake system150shown inFIG.6also includes backup ABS modulator arrangements212B,212D hydraulically interposed between each of the third and fourth three-way valves198C,198A (respectively) and a corresponding brake152B,152D of the selected one of the pair of front wheel brakes and the pair of rear wheel brakes which is associated with the first power transmission unit168A. The first and second fluid separators100A,100B are each hydraulically interposed between a backup ABS modulator arrangement212B,212D and the corresponding brake152B,152D of the selected one of the pair of front wheel brakes and the pair of rear wheel brakes which is associated with the first power transmission unit168A.

The backup ABS modulator arrangements212B,212D, may include iso valves206B′,206D′ and dump valves208B′,208D′, for providing desired iso/dump fluid control features and performance to the associated front wheel brakes152B,152D, even in the backup braking mode where fluid is supplied to the front wheel brakes152B,152D by the second power transmission unit168B through action of the respective first and second fluid separators100A,100B. This backup braking mode is facilitated by the first and second fluid separators100A,100B as described in detail above.

Using the arrangement of valves inFIG.6, the fluid pressures at each of the wheel brakes152can be controlled independently from one another during normal, non-failure operation and in a backup braking mode.

As used herein, the singular forms “a”, “an”, and “the” can include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, as used herein, can specify the presence of stated 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.

As used herein, the term “and/or” can include any and all combinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, “adjacent”, etc., another element, it can be directly on, attached to, connected to, coupled with, contacting, or adjacent the other element, or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with, “directly contacting”, or “directly adjacent” another element, there are no intervening elements present. It will also be appreciated by those of ordinary skill in the art that references to a structure or feature that is disposed “directly adjacent” another feature may have portions that overlap or underlie the adjacent feature, whereas a structure or feature that is disposed “adjacent” another feature might not have portions that overlap or underlie the adjacent feature.

Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “proximal”, “distal”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms can encompass different orientations of a device in use or operation, in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features.

As used herein, the phrase “at least one of X and Y” can 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, at a particular time, include X, Y, or a combination of X and Y, the selection of which could vary from time to time. In contrast, the phrase “at least one of X” can be interpreted to include one or more Xs.

It will be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a “first” element discussed below could also be termed a “second” element without departing from the teachings of the present disclosure. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

While aspects of this disclosure have been particularly shown and described with reference to the example aspects above, it will be understood by those of ordinary skill in the art that various additional aspects may be contemplated. For example, the specific methods described above for using the apparatus are merely illustrative; 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 apparatus, or components thereof, into positions substantively similar to those shown and described herein. In an effort to maintain clarity in the Figures, certain ones of duplicative components shown have not been specifically numbered, but one of ordinary skill in the art will realize, based upon the components that were numbered, the element numbers which should be associated with the unnumbered components; no differentiation between similar components is intended or implied solely by the 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 made up of separate sub-components, with either of these formations involving any suitable stock or bespoke components and/or any suitable material or combinations of materials. Any of the described structures and components could be disposable or reusable as desired for a particular use environment. Any component could be provided with a user-perceptible marking to indicate a material, configuration, at least one dimension, or the like pertaining to that component, the user-perceptible marking potentially aiding a user in selecting one component from an array of similar components for a particular use environment. A “predetermined” status may be determined at any time before the structures being manipulated actually reach that status, the “predetermination” being made as late as immediately before the structure achieves the predetermined status. The term “substantially” is used herein to indicate a quality that is largely, but not necessarily wholly, that which is specified—a “substantial” quality admits of the potential for some relatively minor inclusion of a non-quality item. Though certain components described herein are shown as having specific geometric shapes, all structures of this disclosure may have any suitable shapes, sizes, configurations, relative relationships, cross-sectional areas, or any other physical characteristics as desirable for a particular application. Any structures or features described with reference to one aspect or configuration could be provided, singly or in combination with other structures or features, to any other aspect or configuration, as it would be impractical to describe each of the aspects and configurations discussed herein as having all of the options discussed with respect to all of the other aspects and configurations. A device or method incorporating any of these features should be understood to fall under the scope of this disclosure as determined based upon the claims below and any equivalents thereof.

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