CN116461478A - Brake system with fluid storage auxiliary brake module - Google Patents

Abstract

The invention relates to a brake system with a fluid storage auxiliary brake module. A brake system for actuating at least one wheel brake includes a reservoir and a master cylinder operable to provide a brake signal in response to actuation of a brake pedal connected to the master cylinder. The master cylinder is selectively operable to generate brake actuation pressure to at least one output to hydraulically actuate at least one wheel brake during a manual propulsion mode. The power transmission unit is configured to actuate at least one of the wheel brakes in a non-faulty normal braking mode. The auxiliary brake module is configured to selectively provide hydraulic fluid to each wheel brake in the enhanced braking mode. The auxiliary brake module includes a pump motor driving at least one pump unit. Each pump unit is operatively connected to a fluid accumulator associated with an associated wheel brake to selectively vary the amount of hydraulic fluid provided to the wheel brake.

Description

Brake system with fluid storage auxiliary brake module

Technical Field

The present disclosure relates to an apparatus and method for use with a braking system, and more particularly, to a method and apparatus for actuating a hydraulic braking system for a pair of front brakes and a pair of rear brakes, the hydraulic braking system including an auxiliary braking module having fluid storage capacity.

Background

The brake system may include an anti-lock control including a pedal-operated hydraulic pressure generator disposed in a pressure fluid conduit between the brake pressure generator and the wheel brake and for varying the brake pressure by varying the volume of a chamber containing hydraulic fluid, a brake pressure regulator for determining wheel rotation behavior, a sensor for processing sensor signals and for generating brake pressure control signals, and an electronic circuit. The braking system may also include both anti-lock control and traction slip control, both of which may use a brake pressure regulator to control vehicle braking.

Some hydraulic brake systems include various enhancement features for selectively helping to achieve a desired braking response for one or more wheel brakes in a particular use environment. One exemplary enhancement feature is "over-pressurization" (where a particular brake is provided with a higher pressure than is typically available from a conventional master cylinder arrangement).

Disclosure of Invention

In one aspect, a brake system for actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes is disclosed. The brake system includes a reservoir and a master cylinder operable to provide a brake signal in response to actuation of a brake pedal connected to the master cylinder. The master cylinder is selectively operable during a manual push mode by actuation of the brake pedal to generate brake actuation pressure to at least one output to hydraulically actuate at least one wheel brake. The power transfer unit is configured to selectively provide pressurized hydraulic fluid to actuate at least one of the wheel brakes in a non-faulty normal braking mode. The auxiliary brake module is configured to selectively provide hydraulic fluid to each of the wheel brakes in an enhanced braking mode. Each wheel brake has an associated fluid accumulator. The auxiliary brake module includes a pump motor that drives at least one pump unit associated with an associated wheel brake. Each pump unit is operatively connected to the fluid accumulator associated with the associated wheel brake to selectively vary the amount of hydraulic fluid provided to the associated wheel brake. A main electronic control unit controls the power transmission unit in response to the brake signal. An auxiliary electronic control unit controls the pump motor in response to the brake signal. A first two-position three-way valve and a second two-position three-way valve are provided. Each of the first two-position three-way valve and the second two-position three-way valve is hydraulically connected with the master cylinder, the power transmission unit, and at least selected wheel brakes. The first and second two-position three-way valves selectively control hydraulic fluid flow from a selected one of the master cylinder and the power transfer unit to at least the selected wheel brake. An iso/pressure-reducing control valve device is hydraulically interposed between at least one of the first and second two-position three-way valves and at least the selected wheel brake. The parallel iso valve device is hydraulically interposed between the selected pump unit and the corresponding wheel brake.

Drawings

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

FIG. 1 is a schematic hydraulic diagram of a brake system in a first configuration according to one aspect of the present disclosure; and

fig. 2 is a schematic hydraulic diagram of the brake system of fig. 1 in a second configuration.

Detailed Description

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

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

Fig. 1-2 schematically illustrate a brake system 100 for actuating a pair of front wheel brakes and a pair of rear wheel brakes in a first configuration and a second configuration, respectively. The brake system 100 is shown here as a hydraulic brake system, wherein a braking force is applied to the brake system 100 using fluid pressure. The brake system 100 may be suitably used in a ground vehicle, such as a motor vehicle having four wheels, with wheel brakes associated with each wheel. In addition, the braking system 100 may be provided with other braking functions, such as anti-lock braking (ABS) and other slip control features, to effectively brake the vehicle. The components of the brake system 100 may be housed in one or more blocks or housings. The block or housing may be made of a solid material (e.g., aluminum) that has been drilled, machined, or otherwise shaped to accommodate the various components. The fluid conduit may also be formed in a block or housing.

In the illustrated embodiment of the brake system 100, there are four wheel brakes 102A,102B,102C, and 102D. The wheel brakes 102a,102b,102c, and 102D may have any suitable wheel brake configuration that is electrically operated and/or operated by the application of pressurized brake fluid. Each wheel brake 102a,102b,102c, and 102D may include, for example, a brake caliper mounted on the vehicle to engage a friction element (e.g., a brake disc) that rotates with the wheel to effect braking of the associated wheel. Wheel brakes 102a,102b,102c, and 102D may be associated with any combination of front and rear wheels of a vehicle in which brake system 100 is installed. For example, the brake system 100 may be configured as a vertically-split system as shown, such that pressurized hydraulic fluid is provided from one source (e.g., a single outlet of a master cylinder) to actuate both of the pair of front wheel brakes 102B and 102D, and from another source to actuate both of the pair of rear wheel brakes 102A and 102C. In the illustrated embodiment of the brake system 100, in the non-faulty normal braking mode, the power transfer unit 104 provides fluid to all of the pair of front wheel brakes 102B and 102D and the pair of rear wheel brakes 102A and 102C.

The auxiliary or back-up pressure circuit (indicated generally by the dashed line "2" in the figures) may include suitable components for selectively providing pressurized hydraulic fluid to actuate the pair of front wheel brakes 102B and 102D and/or the pair of rear wheel brakes 102A and 102C when the brake system 100 is in at least one enhanced braking mode, as will be discussed in more detail below.

In this example, the wheel brake 102A may be associated with a rear right wheel of the vehicle in which the brake system 100 is installed, and the wheel brake 102B may be associated with a front left wheel. The wheel brake 102C may be associated with the left rear wheel and the wheel brake 102D may be associated with the right front wheel. Alternatively, although not shown herein, the brake system 100 may be configured as a diagonally-split brake system such that two wheel brakes 102, as viewed from one hydraulic fluid source (e.g., a single output of the master cylinder), are "paired" with diagonally-positioned wheels of the vehicle, and the other two "paired" wheel brakes 102 are associated with wheels on another diagonal of the vehicle. (it is contemplated that one of ordinary skill in the art may reconfigure various other components (e.g., electric brake motors) to accommodate such altered systems in certain use environments.

The brake system 100 also includes a brake pedal unit, indicated generally at 108, a pedal simulator, indicated generally at 110, and a fluid reservoir 112. The reservoir 112 stores and holds hydraulic fluid for the brake system 100. The fluid within reservoir 112 is preferably maintained at or about atmospheric pressure, but may be stored at other pressures if desired. The reservoir 112 is schematically shown with three tanks or sections to which fluid lines are connected. These portions may be separated by several inner walls within the reservoir 112 and provided to prevent complete discharge of the reservoir 112 in case one of these portions is depleted due to leakage via one of the three lines connected to the reservoir 112. Alternatively, the reservoir 112 may comprise a plurality of separate housings. The reservoir 112 may include at least one fluid level sensor 114 (two shown for redundancy) for detecting the fluid level of one or more portions of the reservoir 112.

The power transmission unit 104 of the brake system 100 serves as a pressure source to provide desired pressure levels to the hydraulically operated wheel brakes 102a,102b,102c and 102D during typical or normal non-faulty brake applications. After the brakes are applied, fluid from the wheel brakes 102a,102b,102c, and 102D may be returned to the power transmission unit 104 and/or diverted to the reservoir 112. In the illustrated embodiment, the power transfer unit 104 is shown as a double-acting plunger type power transfer unit, but a single-acting plunger or any other desired type of controllable hydraulic fluid booster may additionally or alternatively be provided to the brake system 100. It is also contemplated that other configurations (not shown) of the brake system 100 may include hydraulic control of only a selected one of the pair of front and rear wheel brakes (the other pair being electronically controlled/electrically actuated). After aspects of the art, one of ordinary skill in the art will be able to readily provide such an arrangement for a desired use environment.

The auxiliary brake module 106 of the brake system 100 serves as a pressure source to provide a desired pressure level to selected wheel brakes 102 in a standby or "fail" condition (at which time the power transfer unit 104 is unable to provide fluid to those selected wheel brakes for some reason). The auxiliary brake module 106 may be used to selectively provide hydraulic fluid to at least one of the front wheel brakes 102B and 102D and/or the rear wheel brakes 102A and 102C in the stand-by braking mode, but may also selectively provide hydraulic fluid to at least one of the front wheel brakes 102B and 102D and/or the rear wheel brakes 102A and 102C in the enhanced braking mode, which may occur independently and/or concurrently with the stand-by braking mode or the non-malfunctioning normal braking mode. Examples of suitable enhanced braking mode functions that may be used with the braking system 100 include, but are not limited to, "over-pressurization" (where a higher pressure is provided to a particular brake than is typically available from a conventional master cylinder device) and "volume increase" (where more fluid is provided to a particular brake than is typically available from a conventional master cylinder device). It is contemplated that, for example, the pair of front wheel brakes 102B and 102D may be provided with an over-pressurization and the pair of rear wheel brakes 102A and 102C may be provided with a volume increase, either simultaneously or at different times. It is also contemplated that one enhancement mode feature (e.g., over-pressurization) may be applied to one or more wheel brakes 102 simultaneously and/or separately from another enhancement mode feature (e.g., volume increase) that is applied to one or more other wheel brakes 102. For example, a pair of front wheel brakes 102B and 102D may be placed in an over-pressurized state while rear wheel brakes 102A and 102C are placed in a volume-increased state as desired for a particular use application. One of ordinary skill in the art will be readily able to construct the brake system 100 as desired for any particular application.

The brake system 100 also includes at least one electronic control unit ("ECU") 116, a main ECU 116A and an auxiliary ECU 116B are shown and described herein. The ECUs 116a,116b may include a microprocessor and other circuitry. The ECUs 116a,116b receive the various signals, process the signals, and control the operation of the various electrical components of the brake system 100 in a wired and/or wireless manner in response to the received signals. The ECUs 116a,116b may be connected to various sensors such as a reservoir level sensor 114, a pressure sensor, a stroke sensor, a switch, a wheel speed sensor, and a steering angle sensor. The ECUs 116a,116b may also be connected to an external module (not shown) for receiving information related to the yaw rate, lateral acceleration, longitudinal acceleration, or other characteristics of the vehicle operation for any reason, such as, but not limited to, controlling the brake system 100 during vehicle braking, stability operation, or other modes of operation. In addition, the ECUs 116a,116b may be connected to an instrument cluster for collecting and providing information related to warning indicators such as ABS warning lights, brake fluid level warning lights, and traction control/vehicle stability control indicator lights.

Although not shown here, at least one brake motor may be provided for selectively electrically actuating at least one wheel brake 102 at least in a parking brake mode that functions in a complementary manner to the hydraulically actuated service brake 102. However, regardless of whether any of the included brake motors function as parking brakes during normal non-faulty braking, the brake motors may be used in a stand-by mode as an electrically actuated alternative to the hydraulically operated wheel brakes 102 when the hydraulic operation of the wheel brakes is not available for some reason. The primary electronic control unit 116A and/or the secondary electronic control unit 116B may be configured to control some combination of at least one of the power transmission unit 104, any available brake motors, and pump motors, as desired for a particular use environment (e.g., in response to a brake signal obtained from the brake pedal unit 108, for example).

As schematically shown in fig. 1, the brake pedal unit 108 includes a master cylinder 120 having a housing 122, the housing 122 defining a longitudinally extending bore for slidably receiving various cylindrical pistons and other components therein. Examples of such components are a first spring and a second spring extending longitudinally in series within the bore, as shown. Note that the housing 122 is not particularly schematically shown in the figures, but the walls of the longitudinally extending holes are schematically shown. The housing 122 may be formed as a single unit or may include two or more separately formed sections that are connected together. For some use environments, master cylinder 120 may be of the tandem master cylinder type.

MC master piston 124 is connected to brake pedal 126 by a link arm 128. Under certain conditions, leftward movement of the MC master piston 124 may cause an increase in pressure within the master cylinder 120.

The pedal simulator 110 is in selective fluid communication with the master cylinder 120 to provide a predetermined brake pedal response. As shown, the pedal simulator 110 is connected to the master cylinder 120 by one or more hydraulic passages, but it is contemplated that "selective fluid communication" may be provided by integrating the pedal simulator 110 into the master cylinder 120.

More specifically, the master cylinder 120 is in fluid communication with the pedal simulator 110 via a master cylinder passage 130. The MC master piston 124 is slidably disposed in a bore of the housing 122 of the master cylinder 120. The configuration of the master cylinder 120 allows at least a portion of fluid communication between the bore of the housing 122 and the reservoir 112 via the reservoir tube 132 when the brake pedal unit 108 is in its rest position (the driver does not depress the brake pedal 126). Accordingly, the pedal simulator 110 is in selective fluid communication with the master cylinder 120 to provide a predetermined brake pedal 126 response (e.g., brake pedal "feel") to the driver.

The brake system 100 may further include an optional solenoid actuated simulator test valve 134 that may be electronically controlled between an open position and a power closed position; the simulator test valve 134 may include a test valve spring that biases the simulator test valve 134 toward an open state. The simulator test valve is fluidly located between the reservoir 112 and the master cylinder 120 to selectively allow fluid communication therebetween. The simulator test valve 134 may not be needed during normal brake application or for manual push-through mode. The simulator test valve 134 may be actuated to resist opening at a predetermined pressure during various test modes to determine proper operation of other components of the brake system 100. For example, the simulator test valve 134 may be actuated to a closed position to prevent venting of the reservoir 112 via the reservoir conduit 132, thereby monitoring fluid flow to determine if leakage may occur through seals of various components of the brake system 100.

The simulator pressure chamber 136 of the pedal simulator 110 is in fluid communication with a pedal simulator passage 138, the pedal simulator passage 138 being in fluid communication with the master cylinder 120 of the brake pedal unit 108 via a simulator valve 140. One example of a desired operation of the simulator valve is during a fault and/or an initial/start condition in which the brake pedal unit 108 is used to provide a source of pressurized fluid to the wheel brakes 102a,102b,102c, and 102D in a push manner, as described herein.

The brake pedal unit 108 is connected to the brake pedal 126 and is actuated by the driver of the vehicle when the driver presses the brake pedal 126. Brake sensors or switches 142 (three are shown for redundancy) may be electrically connected to the ECUs 116A,116B to provide a brake signal indicative of depression of the brake pedal 126. The brake signal may be of a binary (brake off/on) type and/or a proportional/graduated signal indicative of the speed, acceleration, duration and/or amount of depression of the brake pedal 126. That is, the master cylinder 120 is operable to provide a brake signal in response to actuation of the brake pedal 126 coupled thereto.

The brake pedal unit 108 may be used as a backup source of pressurized fluid to substantially replace the normally supplied pressurized fluid source from the power transmission unit 104 during certain fault conditions of the brake system 100 and/or upon initial start-up of the brake system 100. This condition is referred to as a manual push event or "manual application" and may be accomplished in coordination with or independent of actuation of the auxiliary brake module 106.

In this push mode, the brake pedal unit 108 may supply pressurized fluid to at least one of the master cylinder output 144 and the master cylinder channel 130, which is then directed to the wheel brakes 102a,102b,102c, and 102D as desired. This flow is forced from the master cylinder 120 primarily under mechanical pressure from the driver's foot acting on the brake pedal 126. That is, the master cylinder 120 is selectively operable during a manual push mode by actuating a brake pedal 126 connected to the master cylinder 120 to generate a brake actuation pressure for at least one of a first output (shown schematically herein as a master cylinder channel 130) and a second output (shown schematically herein as a master cylinder output 144) for hydraulically actuating at least one of the pair of front wheel brakes 102b,102d and the pair of rear wheel brakes 102a,102 c.

First two-position three-way valve 146 and second two-position three-way valve 148 are provided to brake system 100, respectively, as shown. Each of the first and second three-way valves 146 and 148 is hydraulically connected to the master cylinder 120, the power transmission unit 104, and at least one selected wheel brake of each pair of the front and rear wheel brakes 102. For example, as shown, a first three-way valve 146 is in fluid communication with the left and right rear wheel brakes 102A,102C and a second three-way valve 148 is in fluid communication with the left and right front wheel brakes 102B, 102D. The first and second three-way valves 146 and 148 selectively control hydraulic fluid flow from a selected one of the master cylinder 120 and the power transfer unit 104 to at least a selected one of the front and rear wheel brakes 102 and 102. By using the first three-way valve 146 and the second three-way valve 148, hydraulic fluid may be directed to the wheel brakes 102 in a desired manner (from the master cylinder 120 or the power transfer unit 104) to assist in the boost brake control and provide a desired response time and efficient pressure flow to the respective wheel brakes 102 associated with each three-way valve. For cost and packaging reasons, but also to reduce current consumption, a single three-way valve 146 or 148 is shown here instead of one normally closed valve and one normally open valve. This is primarily because in some use environments, a normally open valve may require an undesirably high force spring, thereby avoiding the normally open valve becoming hydraulically locked closed if power is lost during pressurized brake application, which may trap brake pressure and/or cause undesired braking when the pedal is released.

The figure also depicts a supplemental check valve 150 fluidly located between the reservoir 112 and the power transmission unit 104. When present, the supplemental check valve 150 may be provided to assist in refilling the power transfer unit 104 (or components thereof) under predetermined conditions. For example, when the DAP-type power transfer unit 104 builds pressure during its retraction stroke by pushing fluid out of an annular chamber behind a double-acting plunger ("DAP") head, the supplemental check valve 150 may help facilitate refilling of the chamber in front of the DAP head. This is done, for example, during slip control if additional flow to the brake is required after the DAP has fully stroked forward.

A normally closed double acting plunger ("DAP") valve 152 and a normally open DAP valve 154 are hydraulically interposed between the power transfer unit 104 and at least one of the first and second three-way valves 146, 148.

An iso/pressure-reducing control valve device 156 is hydraulically interposed between the power transmission unit 104 and the paired front wheel brakes 102b,102d and paired rear wheel brakes 102a,102 c. Each iso/pressure relief control valve device 156 is controlled by the main ECU 116A. Each iso/relief control valve arrangement 156 includes an ABS iso valve 157 and an ABS relief valve 158, respectively, arranged in series. The normally open iso valve 157 for each iso/pressure-reducing control valve device 156 is hydraulically located between the respective wheel brake 102 and the power transfer unit 104, and the normally closed pressure-reducing valve 158 for each iso/pressure-reducing control valve device 156 is hydraulically located between the respective wheel brake 102 and the reservoir 112 for the corresponding wheel brake 102. Here, for clarity in the figures, the iso valve 157 and the pressure relief valve 158 (and generally each iso/pressure relief control valve device 156) are attached with the letter "B" or "D" (the letter "B" or "D" referring to the respective front wheel brakes 102B and 102D) or with the letter "a" or "C" (the letter "a" or "C" referring to the respective rear wheel brakes 102A and 102C), respectively, so-labeled valves being associated with these brakes.

As shown in fig. 1 and 2, an iso/pressure relief control valve arrangement 156 may be hydraulically interposed between a respective first or second three-way valve 146, 148 and a corresponding one of the pair of hydraulically actuated brakes.

Accordingly, each iso/pressure-reducing control valve arrangement 156 downstream of the power transfer unit 104 includes an iso valve 157 and a pressure-reducing valve 158, with the iso157 and pressure-reducing valves 158 being controlled between their open and closed positions to provide different brake pressures between the wheel brakes 102 as desired for a particular braking situation. The iso/pressure-reducing control valve device 156 may selectively provide slip control to at least one wheel brake 102 of the pair of front wheel brakes 102b,102c and the pair of rear wheel brakes 102a,102d that are powered by the power transmission unit 104. More broadly, the iso/pressure relief control valve arrangement 156 and/or other valves (any of which may be solenoid operated and of any suitable configuration) of the brake system 100 may be used to help provide controlled braking operations such as, but not limited to, ABS, traction control, vehicle stability control, dynamic post-proportioning, regenerative braking blending, and autonomous braking.

Focusing now on the auxiliary brake module 106, schematically indicated by the dashed line "2" in fig. 1 and 2, an auxiliary device is provided to hydraulically power and control one or more of the wheel brakes 102 as part of the enhanced braking mode or for any other reason in case of a fluid power loss from the power transfer unit 104. As shown, the auxiliary brake module 106 of the brake system 100 is configured to selectively provide hydraulic fluid to at least one brake (in the illustrated configuration, all four brakes) of the pair of front wheel brakes 102b,102d and the pair of rear wheel brakes 102a,102c in an enhanced braking mode.

As shown, the auxiliary brake module 106 may include a pump motor (e.g., an electrically driven pump motor 118) for driving at least one pump unit 160 associated with the associated wheel brake 102. Each pump unit 160 is operatively connected to a fluid accumulator 161 (e.g., of the free floating piston type, without springs, schematically shown in the drawings). The pump unit 160 and the fluid accumulator 161 are cooperatively actuated to selectively vary the amount of hydraulic fluid provided to the associated wheel brake.

The at least one pump unit 160 may be, for example, a pump piston type, or may be of any desired type including, but not limited to, a piston pump, a gear pump, a gerotor pump, and a vane pump, and/or any combination thereof. The pump unit 160 may include an integrated pump motor (not shown), and may also or alternatively include a separate "main" pump motor 118 as shown. When the pump unit 160 is a pump piston of a rotary type pump, at least one pump piston may be provided for each wheel brake 102. It is contemplated that auxiliary electronic control unit 116B may control at least one of pump motor 118 and at least one pump unit 160 in an enhanced braking mode (independent of the normal/standby mode state of brake system 100) in response to a braking signal generated by brake pedal unit 108.

Regardless of the type of pump unit 160 and the control scheme provided, the fluid accumulators 161 assist in selectively providing hydraulic fluid to the respective wheel brakes 102 in an amount that may be provided, for example, by the master cylinder 120 in a manual push or stand-by braking mode. Particularly for very large trucks, the wheel brakes 102 may be large enough that the master cylinder 120 cannot easily move enough hydraulic fluid to provide the desired brake response and pedal "feel" to the operator. Thus, the fluid accumulator 161 may serve as a pseudo reservoir local to the brake, such that the wheel brakes 102 do not need to additionally draw hydraulic fluid from the reservoir 112 in certain situations. Indeed, in some use environments, the auxiliary brake module 106 may be connected to the reservoir 112 only indirectly, with the master cylinder 120 fluidly interposed between the auxiliary brake module 106 and the reservoir 112. A check valve 170 may be provided to the auxiliary brake module 106 as needed to prevent the fluid accumulator 161 from refilling from the master cylinder 120 during the enhanced braking mode (including over-pressurization or volume increase).

In fig. 1 and 2, a parallel iso valve device 162 is provided to each wheel brake 102 as part of the auxiliary brake module 106. The parallel iso valve devices 162 are hydraulically interposed between the corresponding iso/pressure reducing control valve devices 156 and the corresponding wheel brakes 102. Each parallel iso valve device 162 for the wheel brakes 102 includes a first parallel iso valve 164 and a second parallel iso valve 166, respectively. Each of the parallel iso valve devices 162 may help provide pressure build-up in the corresponding wheel brakes 102 when the power transfer unit 104, the main ECU 116A, or any other component fails, which would otherwise contribute to a normal, non-failed braking mode/condition if functioning properly. Each parallel iso valve device 162 may additionally or alternatively help provide an enhanced braking mode, as previously mentioned.

Much like the main electronic control unit 116A may control at least one iso/pressure-reducing control valve arrangement to provide slip control (e.g., traction compensation) features to the corresponding wheel brakes 102 in the non-faulty normal braking mode, the auxiliary electronic control unit 116B may control at least one of the parallel iso valve arrangements 162 to provide enhanced braking features (e.g., over-pressurization and/or volume increase) and/or a degree of slip control (e.g., traction compensation) features to the corresponding wheel brakes 102 in the stand-by braking mode.

As described above, the at least one brake sensor 142 may facilitate providing a brake signal to the primary electronic control unit 116A and/or the secondary electronic control unit 116B. Although at least one brake sensor 142A (two provided for redundancy) is shown in the figures as providing a brake signal responsive to actuation of the brake pedal 126, as evidenced by the travel of the master cylinder master piston 124 (directly or indirectly), the brake system 100 may also include another brake sensor 142B. When present, the brake sensor 142B may be located remotely from the brake sensor 142A (e.g., a brake sensor providing a brake signal to the main electronic control unit 116A) and operatively connected to the brake pedal 126 for providing a brake signal to the auxiliary electronic control unit 116B in response to actuation of the brake pedal 126.

The brake signal from the brake sensor 142B may be used to direct operation of the auxiliary brake module 106, particularly in a stand-by braking mode in which the auxiliary brake module 106 assists manual actuation from the master cylinder 120 to provide the enhanced braking mode function (e.g., volume increase and/or over-pressurization) to the at least one wheel brake 102. Such a function of the brake sensor 142B may be helpful, for example, when all of the brake sensors 142A are not available (e.g., when the brake system 100 is in the stand-by braking mode), such as due to local driving conditions, vehicle loading, and/or any other reason, and it is desired that the wheel brakes 102 of one axle (front/rear) be in the over-pressurized mode, while the wheel brakes 102 of the other axle (rear/front) be in the volume-increased mode.

The auxiliary brake module 106 may include at least one pressure sensor 168 (three shown) at any desired location to provide a pressure signal to the auxiliary electronic control unit 116B in response to the hydraulic fluid pressure sensed at the corresponding location of the auxiliary brake module 106. The pressure signal may be used for any desired reason, such as, but not limited to, facilitating closed loop control of at least a portion of the brake system 100, detecting and/or verifying pressurization of hydraulic fluid, and/or for any other reason. The pressure of the hydraulic fluid may be sensed directly or indirectly with a pressure sensor (shown generally as "P") at any desired location in the brake system 100, although the pressure sensor 168 is shown as an example in the auxiliary brake module 106. It is contemplated that any provided pressure sensor 168 may be in electrical communication with at least one of primary electronic control unit 116A and secondary electronic control unit 116B in a wired or wireless manner to communicate a pressure signal to primary electronic control unit 116A and secondary electronic control unit 116B in response to a sensed fluid pressure, as desired for a particular use environment.

It is contemplated that components located within the dashed line "2" in fig. 1 may be hydraulically (if not mechanically) spaced apart from components outside of the line in the vehicle (i.e., by being located remotely from each other within the brake system 100 and at least from the common housing or block). Those of ordinary skill in the art will be readily able to provide suitable parallel-connected iso valve devices 162, pump units 160, fluid accumulators 161, pump motors 118, or any other auxiliary brake module 106 components for the intended use environment of the present invention.

With the valve arrangement in the figures, even though the brake system 100 may include a single pressure source (e.g., the power transmission unit 104 and/or the master cylinder 120), the fluid pressure at each wheel brake 102 may be controlled independently of each other during normal non-faulty operation. In addition, in the event of a failure of both the power transmission unit 104 and the master cylinder 120, the auxiliary brake module 106 may provide a "brake-by-wire" or autonomous braking function to the brake system 100 due, at least in part, to the hydraulic fluid contained in the fluid accumulator 161.

Referring now to FIG. 2, a second configuration of the brake system 100 is depicted, as portions or all of the brake system 100 may be used with other components of the present invention, as desired. For brevity, descriptions of similar components and operations performed elsewhere in this application will not necessarily be repeated for each and every described configuration or aspect of the brake system 100, but should be deemed appropriate for use with similarly numbered portions of other configurations.

In the brake system 100 shown in fig. 2, two pump units 160 for at least one wheel brake 102 (here, for each of a pair of front wheel brakes 102a,102 c) are shown. Such a "differential arrangement" of the pump unit 160 may be provided for any desired reason. For example, when each pump unit 160 is a pump piston of a rotary-type pump, having more pump pistons than just four pump pistons (when one is provided per wheel brake 102) may have the advantage of flow ripple. In some use environments, it may also be desirable to build up pressure in the front wheel brakes 102a,102c before the rear wheel brakes 102b,102 d. It is also contemplated that one or more of the wheel brakes 102 may be omitted entirely from the arrangement of the auxiliary brake module 106, i.e., that no corresponding pump unit 160 or fluid accumulator 161 associated with the wheel brakes 102 is present. One of ordinary skill in the art will be able to readily construct the pump unit 160 of the brake system 100 as desired for a particular use environment.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, 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" may 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 to," "contacting," "adjacent to" another element, etc., it can be directly on, attached to, connected to, coupled to, contacting or adjacent to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on," "directly attached to," "directly connected to," "directly coupled to," "directly contacting," or "directly adjacent to" another element, there are no intervening elements present. Those of ordinary skill in the art will further appreciate that references to a structure or feature that is disposed "directly adjacent" another feature may have portions that overlap or underlie the adjacent feature, and that structures or features that are disposed "adjacent" another feature may have no portions that overlap or underlie the adjacent feature.

Spatially relative terms, such as "under … …," "under … …," "lower," "above … …," "upper," "proximal," "distal," and the like, may be used herein to facilitate describing one element or feature's relationship to another element or feature as illustrated. It will be understood that spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the 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" may be construed 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, that element may include X, Y or a combination of X and Y at a particular time, the selection of which may vary over time. Conversely, the phrase "at least one of X" may be interpreted to include one or more X.

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 element. Thus, a "first" element discussed below could also be termed a "second" element without departing from the teachings of the present disclosure. The order of operations (or steps) is not limited to the order in which it is presented in the claims or figures unless specifically indicated otherwise.

While aspects of the present disclosure have been particularly shown and described with reference to the foregoing exemplary aspects, those of ordinary skill in the art will understand that various additional aspects are contemplated. For example, the specific methods of using the device described above are merely illustrative; one of ordinary skill in the art may readily determine any number of tools, sequences of steps, or other means/options for placing the above-described devices or components thereof in a substantially similar location as shown and described herein. Some of the repeated components shown are not specifically numbered in order to preserve clarity in the figures, but one of ordinary skill in the art will recognize, based on the numbered components, the element numbers that should be associated with the unnumbered components; the presence or absence of element numbers in the figures does not intend or imply a distinction between similar components. Any of the described structures and components may be integrally formed as a single unitary piece or formed of separate sub-components, any of these constructions including any suitable stock or custom components and/or any suitable materials or combinations of materials. Any of the described structures and components may be disposable or reusable as desired for a particular use environment. Any component may have user-perceptible indicia to indicate the material, construction, at least one dimension, etc. associated with the component, the user-perceptible indicia potentially helping a user select one component from an array of similar components for a particular use environment. The "predetermined" state may be determined at any time before the manipulated structure actually reaches the state, the "predetermined" being made as late as before the structure reaches the predetermined state. The term "substantially" is used herein to mean that the mass is largely (but not necessarily entirely) specified — the "substantially" mass allows for relatively less likelihood of containing non-quality items. Although certain components described herein are illustrated as having particular geometries, all of the structures of the disclosure can have any suitable shape, size, configuration, relative relationship, cross-sectional area, or any other physical characteristic desired for a particular application. Any structure or feature described with reference to one aspect or configuration may be provided to any other aspect or configuration, alone or in combination with other aspects or features, as it would be impractical to describe each aspect and configuration 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 should be understood to fall within the scope of the disclosure as determined based on the following claims and any equivalents thereof.

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

RELATED APPLICATIONS

The present application claims priority from U.S. provisional application No.63/300,773, filed on 1 month 19 2022, the contents of which are incorporated herein by reference in their entirety.

Claims (19)

1. A brake system for actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes, the brake system comprising:

a reservoir;

a master cylinder operable to provide a brake signal in response to actuation of a brake pedal connected to the master cylinder, the master cylinder being selectively operable to generate brake actuation pressure to at least one output to hydraulically actuate at least one wheel brake by actuation of the brake pedal during a manual push mode;

a power transfer unit configured to selectively provide pressurized hydraulic fluid to actuate at least one of the wheel brakes in a non-faulty normal braking mode;

an auxiliary brake module configured to selectively provide hydraulic fluid to each of the wheel brakes in an enhanced braking mode, each wheel brake having an associated fluid accumulator, the auxiliary brake module including a pump motor driving at least one pump unit associated with the associated wheel brake, each pump unit operatively connected to the fluid accumulator associated with the associated wheel brake to selectively vary an amount of hydraulic fluid provided to the associated wheel brake;

A main electronic control unit for controlling the power transmission unit in response to the brake signal;

an auxiliary electronic control unit for controlling the pump motor in response to the brake signal;

a first two-position three-way valve and a second two-position three-way valve, each of the first two-position three-way valve and the second two-position three-way valve being hydraulically connected to the master cylinder, the power transfer unit, and at least a selected wheel brake, the first two-position three-way valve and the second two-position three-way valve selectively controlling hydraulic fluid flow from a selected one of the master cylinder and the power transfer unit to at least the selected wheel brake;

an iso/pressure reducing control valve device hydraulically interposed between at least one of the first and second two-position three-way valves and at least the selected wheel brake; and

a parallel iso valve device hydraulically interposed between a selected pump unit and the corresponding wheel brake.

2. The braking system of claim 1, wherein the power transfer unit is a double-acting plunger.

3. The braking system of claim 1, wherein the pump unit is of a pump piston type.

4. A brake system according to claim 3, wherein each pump unit is a pump piston of a rotary type pump having at least one pump piston for each wheel brake.

5. The brake system according to claim 1, wherein at least two pump units are provided for at least one of the wheel brakes.

6. The brake system according to claim 5, wherein each pump unit is a pump piston of a rotary type pump having at least two pump pistons for each of the pair of front wheel brakes.

7. The braking system of claim 1, comprising a normally closed DAP valve and a normally open DAP valve hydraulically interposed between the power transfer unit and the first and second two-position three-way valves.

8. The braking system according to claim 1, wherein the master cylinder includes:

a housing defining a longitudinally extending bore; and

a first spring and a second spring extending longitudinally in series within the bore.

9. The brake system of claim 1, wherein each iso/pressure reduction control valve device selectively provides slip control to a corresponding wheel brake.

10. The brake system of claim 9, wherein each iso/pressure-relief control valve device includes a corresponding iso valve and a corresponding pressure-relief valve for a corresponding wheel brake.

11. The brake system of claim 1, wherein each parallel iso valve device includes a first parallel iso valve and a second parallel iso valve for the corresponding wheel brake.

12. The brake system of claim 1, wherein at least one of the master cylinder and the brake pedal includes at least two brake sensors, each brake sensor providing a brake signal in response to actuation of the brake pedal, a selected one of the brake sensors providing a brake signal to the primary electronic control unit and the other one of the brake sensors providing a brake signal to the secondary electronic control unit.

13. The braking system of claim 1, wherein the auxiliary electronic control unit controls at least one of the pump motor and the at least one pump unit in the enhanced braking mode in response to the braking signal.

14. The braking system of claim 1, wherein the main electronic control unit controls at least one iso/pressure reduction control valve device in a non-faulty normal braking mode to provide a slip control feature to the corresponding wheel brake.

15. The braking system of claim 1, wherein the auxiliary electronic control unit controls at least one parallel iso valve device in a stand-by braking mode to provide slip control features to the corresponding wheel brakes.

16. The braking system of claim 1, wherein the auxiliary braking module is indirectly connected to the reservoir, the master cylinder being fluidly interposed between the auxiliary braking module and the reservoir.

17. The braking system of claim 1, wherein the auxiliary braking module includes at least one pressure sensor configured to provide a pressure signal to the auxiliary electronic control unit in response to a sensed hydraulic fluid pressure in the auxiliary braking module.

18. The braking system of claim 1, wherein the master cylinder is of a tandem master cylinder type.

19. The brake system of claim 1 including a pedal simulator in selective fluid communication with the master cylinder to provide a predetermined brake pedal response.