Apparatus and method for controlling a hydraulic brake system

Abstract

The present disclosure relates to apparatuses and methods for controlling a hydraulic brake system. A brake system selectively actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes includes a reservoir and a master cylinder. A power transfer unit is configured to selectively provide pressurized hydraulic fluid. A pair of rear brake motors selectively electrically actuate rear parking brakes. An electronic control unit controls at least one of the pair of rear brake motors and the power transfer unit. A normally closed DAP valve is hydraulically between the power transfer unit and at least one of a two-position, three-way valve and at least a selected one of the pair of front wheel brakes and the pair of rear wheel brakes. An isolation valve and a dump valve are associated with each wheel brake.

Description

Technical Field

[0001] This disclosure relates to apparatus and methods for controlling a hydraulic brake system, and more specifically, to methods and apparatus for providing independent pressure control of individual wheel brakes in a brake system. Background Technology

[0002] The braking system may include anti-lock braking system (ABS), which includes a pedal-operated hydraulic brake pressure generator, a brake pressure regulator disposed in a pressure fluid conduit between the brake pressure generator and the wheel brakes for changing the brake pressure by altering the volume of a chamber containing hydraulic fluid, a sensor for determining wheel rotational behavior, and electronic circuitry for processing sensor signals and generating brake pressure control signals. The braking system may also include ABS and traction slip control, which can use the brake pressure regulator for braking the controlled vehicle.

[0003] Descriptions of prior art braking systems can be found in U.S. Patent No. 10 / 730,501, entitled “Vehicle Brake System with Auxiliary Pressure Source”, granted to Blaise Ganzel on August 4, 2020, and U.S. Patent Application Publication No. 2020 / 0307538, written by Blaise Ganzel and entitled “Brake System with Multiple Pressure Sources”, published on October 1, 2020, both of which are incorporated herein by reference in their entirety for all purposes. Summary of the Invention

[0004] In one aspect, a braking system is disclosed that selectively actuates at least one of a pair of front wheel brakes and a pair of rear wheel brakes. The braking system includes: a reservoir; and a master cylinder operable during manual push-through mode by actuating a brake pedal connected to the master cylinder to generate brake actuation pressure at a first output, thereby hydraulically actuating at least one of the pair of front wheel brakes and a pair of rear wheel brakes during the manual push-through mode. A power transmission unit is configured to selectively provide pressurized hydraulic fluid during braking events for actuating at least one selected wheel brake of the pair of front wheel brakes and the pair of rear wheel brakes in a power-assisted braking mode. A pair of rear brake motors selectively and electrically actuate corresponding left and right rear wheel parking brakes. An electronic control unit controls at least one of the pair of rear brake motors and the power transmission unit. A pedal simulator is fluidly connected to the master cylinder to provide a predetermined brake pedal response. A two-position three-way valve is hydraulically connected to the master cylinder, the power transmission unit, and at least one selected of the pair of front wheel brakes and the pair of rear wheel brakes. The two-position three-way valve selectively controls the flow of hydraulic fluid from the master cylinder and the power transmission unit to at least one selected of the pair of front wheel brakes and the pair of rear wheel brakes. A normally closed DAP valve is hydraulically located between the power transmission unit and the three-way valve and at least one of the pair of front wheel brakes and the pair of rear wheel brakes. An isolation valve and a deflector valve are associated with each of the pair of front wheel brakes and the pair of rear wheel brakes. For at least one selected of the pair of front wheel brakes and the pair of rear wheel brakes, the isolation valve is hydraulically located between the corresponding wheel brake and the three-way valve, and the deflector valve is hydraulically located between the corresponding wheel brake and the reservoir. Attached Figure Description

[0005] For a better understanding, please refer to the attached diagram, in which:

[0006] Figure 1 This is a schematic hydraulic diagram of a braking system according to one aspect of the present invention in a first configuration;

[0007] Figure 2 This is a schematic partial side view of a second component suitable for use in a braking system according to any aspect of the invention;

[0008] Figure 3 yes Figure 1 The braking system is in a schematic hydraulic diagram of the second configuration;

[0009] Figure 4 yes Figure 1 The braking system is a schematic hydraulic diagram of the third configuration;

[0010] Figure 5 yes Figure 1 The braking system is a schematic hydraulic diagram of the fourth configuration;

[0011] Figure 6 yes Figure 1 The braking system is a schematic hydraulic diagram of the fifth configuration;

[0012] Figure 7 yes Figure 1 The braking system is a schematic hydraulic diagram of the sixth configuration;

[0013] Figure 8 This is a schematic partial side view of a second component suitable for use in a braking system according to any aspect of the invention;

[0014] Figure 9 yes Figure 1 A schematic hydraulic diagram of the braking system during the first operating phase;

[0015] Figure 10 yes Figure 1 A schematic hydraulic diagram of the braking system during the second operating phase;

[0016] Figure 11 yes Figure 1 A schematic hydraulic diagram of the braking system in the third operating phase;

[0017] Figure 12 A schematic partial side view of a third component suitable for use in a braking system according to any aspect of the invention; and

[0018] Figure 13 This is a schematic partial side view of a fourth component suitable for use in a braking system according to any aspect of the invention. Detailed Implementation

[0019] Unless otherwise defined, 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 pertains.

[0020] The present invention comprises, consists of, or is substantially composed of the following features in any combination thereof.

[0021] Figure 1A brake system 100 for actuating a pair of front wheel brakes and a pair of rear wheel brakes in a first configuration is depicted. The brake system 100 is shown herein as a hydraulically boosted brake system, wherein braking force is applied to the brake system 100 using booster fluid pressure. The brake system 100 can be suitably used for ground vehicles, such as autonomous vehicles having four wheels (each wheel having a wheel brake associated with it). Furthermore, the brake system 100 can be equipped with other braking functions (such as anti-lock braking (ABS) and other slip control features) to effectively brake the vehicle. Components of the brake system 100 can be housed in one or more blocks or housings. The blocks or housings can be made of a solid material (such as aluminum) that has been drilled, machined, or otherwise formed to accommodate the various components. Fluid conduits may also be formed within the blocks or housings.

[0022] In the illustrated embodiment of brake system 100, four wheel brakes 102A, 102B, 102C, and 102D are present. Wheel brakes 102A, 102B, 102C, and 102D can have any suitable wheel brake configuration that operates electrically and / or by applying pressurized brake fluid. Each of the wheel brakes 102A, 102B, 102C, and 102D may, for example, include a brake caliper mounted on a vehicle to engage a friction element (such as a brake disc) that rotates with the vehicle wheels, thereby achieving braking of the associated vehicle wheels. Wheel brakes 102A, 102B, 102C, and 102D can be associated with any combination of the front and rear wheels of the vehicle on which brake system 100 is mounted. For example, brake system 100 can be configured as a front / rear split system, as shown, such that a first pressure circuit (in Figure 1 (Indicated by a dashed line "1") is associated with providing fluid to the front wheel brakes 102B and 102D. When the rear wheel brakes 102A and 102C are hydraulically operated and / or the rear wheel brakes 102A and 102C can be electrically operated (e.g., by including a pair of rear wheel motors 103A and 103C, thereby selectively electrically actuating the corresponding left and right rear wheel parking brakes on the rear wheels, as...), Figure 1 When (as shown), the second pressure circuit (in) Figure 1 (The dashed line “2” in the middle) can be associated with providing fluid to the rear wheel brakes 102A and 102C.

[0023] In this example, wheel brake 102A may be associated with the right rear wheel of the vehicle on which brake system 100 is mounted, and wheel brake 102B may be associated with the left front wheel. Wheel brake 102C may be associated with the left rear wheel, and wheel brake 102D may be associated with the right front wheel. Alternatively, although not depicted herein, brake system 100 may be configured as a diagonally separated brake system, such that wheel brakes 102A and 102B are associated with wheels on the front or rear axle of the vehicle, and wheel brakes 102C and 102D are associated with wheels on the other axle of the vehicle.

[0024] Braking system 100 typically includes a brake pedal unit generally indicated by 104, a pedal simulator generally indicated by 106, a power transmission unit generally indicated by 108 (also referred to in some configurations as a single-acting plunger or plunger assembly), and a fluid reservoir 110. Reservoir 110 stores and holds hydraulic fluid for braking system 100. The fluid within reservoir 110 is preferably maintained at atmospheric pressure or approximately atmospheric pressure, but may be stored at other pressures if necessary. Reservoir 110 is schematically shown as having two tanks or sections to which fluid conduit lines are connected. The sections may be separated within reservoir 110 by multiple inner walls and are provided to prevent complete emptying of reservoir 110 in the event that one section is depleted due to leakage via one of the two lines connected to reservoir 110. Alternatively, reservoir 110 may comprise multiple separate housings. The storage device 110 may include at least one level sensor 112 for detecting the level of liquid in one or more sections of the storage device 110.

[0025] The power transmission unit 108 of the brake system 100 serves as a pressure source to provide the desired pressure level to the hydraulically operated wheel brakes 102A, 102B, 102C, and 102D during typical or normal non-faulty braking applications. After braking application, fluid from the hydraulically operated wheel brakes 102A, 102B, 102C, and 102D can be returned to the power transmission unit 108 and / or transferred to the reservoir 110. In the depicted embodiment, the power transmission unit 108 is a double-acting plunger assembly configured to also provide assist pressure to the brake system 100 during the rearward and forward strokes of the piston of the power transmission unit 108. It is also contemplated that the configuration of the brake system 100 (not shown) may include hydraulic control of all four wheels, or hydraulic control of the rear wheels but not the front wheels (then the front wheels would be electrically controlled / actuated). According to various aspects of the invention, those skilled in the art will be able to readily provide such a device for the desired usage environment.

[0026] However, regardless of the specific construction, the power transmission unit 108 is configured to selectively provide pressurized hydraulic fluid to actuate at least one of the selected wheel brakes of a pair of front wheel brakes 102B, 102D and a pair of rear wheel brakes 102A, 102C in a assisted braking mode during a braking event.

[0027] The braking system 100 also includes at least one electronic control unit (“ECU”) 114. The ECU 114 may include a microprocessor and other circuitry. The ECU 114 receives, processes, and controls the operation of various electrical components of the braking system 100 in response to the received signals. The ECU 114 may be connected to various sensors, such as a reservoir level sensor 112, a pressure sensor, a stroke sensor, a switch, a wheel speed sensor, and a steering angle sensor. The ECU 114 may also be connected to an external module (not shown) to receive information related to the vehicle’s yaw rate, lateral acceleration, longitudinal acceleration, or other characteristics of vehicle operation for any reason (such as, but not limited to, controlling the braking system 100 during vehicle braking, stable operation, or other operating modes). Additionally, the ECU 114 may be connected to an instrument cluster to collect and supply information related to warning indications, such as the ABS warning light, the brake fluid level warning light, and the traction control / vehicle stability control indicator. Figure 1 In the configuration of the brake system 100 shown, an electronic control unit 114 is provided to control at least one of a pair of rear brake motors 103 and a power transmission unit 108.

[0028] like Figure 1 As schematically shown, the brake pedal unit 104 includes a master cylinder 115 having a housing 116 for slidably receiving various cylindrical pistons and other components therein. Note that the housing is not specifically shown schematically, but rather the walls of a longitudinally extending orifice are schematically illustrated. The housing 116 may be formed as a single unit or comprise two or more separately formed portions joined together. An input piston 118 is connected to the brake pedal 120 via a linkage arm 122. Leftward movement of the input piston 118 may, in certain circumstances, cause an increase in pressure within the master cylinder 115.

[0029] exist Figure 1 In the braking system 100, the pedal simulator 106 is integrated into the master cylinder 115 by being at least partially enclosed within the housing 116 of the master cylinder 115 to form an integrated pedal simulator 106. Figure 2 The device is shown schematically.

[0030] exist Figure 2The integrated pedal simulator 106 shown is configured to provide a progressive force-travel curve for the brake pedal 120 using multiple force-responsive springs with similar or different spring forces of any desired nature. Two different force-responsive springs, 400A and 400B, are shown and described herein with respect to the pedal simulator 106. Figure 2 As shown, the integrated pedal simulator includes a resilient stop 202 against which a round-end shaft 204 presses to cushion the impact of the shaft 204 during operation of the pedal simulator 106 portion of the master cylinder 115. The shaft 204 is directly connected to the connecting rod arm 122 via the input piston 118. A spring retainer 206 maintains the position of the low-resistance responsive spring 200A, as shown.

[0031] During use, the driver is Figure 2 The upward orientation of the brake pedal 120 forces the linkage arm 122 to the left. The low-resistance responsive spring 200A resists the pushing force until it is compressed until the input piston 118 contacts the far right (at...). Figure 2 The spring retainer 206 is positioned at a point on its surface. Once this contact is established, the spring retainer 206 moves in conjunction with the linkage arm 118 to further compress the higher resistance force within the housing 116 in response to the spring 200B under the maintained compressive force. In this way, the integrated pedal simulator 106 provides the driver with a comfortable and expected "feel" for the brake pedal 120. When the driver maintains the compressive force until the bent head of the shaft 204 contacts the resilient stop 202, this bent or spherical surface helps to distribute the compressive force onto the resilient stop 202 and avoids a jarring, sudden contact with the resilient stop 202, which the driver might find unpleasant and mimics the bouncing sensation of a vacuum booster.

[0032] Refer again Figure 1 The braking system 100 may also include an optional solenoid-actuated simulator test valve 126, which can be electrically controlled between a de-energized position (where opening the valve requires a slight pressure of approximately 0.3 bar) and a power-off position, and is fluidly located between the reservoir 110 and the master cylinder 115. The simulator test valve 126 may not be required during normal braking application or for manual actuation mode. The simulator test valve 126 may include a test valve spring that biases the simulator test valve 126 toward the closed position. An example simulator test valve is shown and described in co-pending patent application serial number No. 17 / 188,227 entitled “Hydraulic Brake Boost” (Attorney’s File No. ZF(BEJ)-029438US PRI), filed concurrently with this application and incorporated herein by reference in its entirety for all purposes.

[0033] The simulator test valve 126 can be actuated to prevent opening at a predetermined pressure during various test modes, thereby determining the proper operation of other components of the brake system 100. For example, the simulator test valve 126 can be actuated to the closed position to prevent discharge to the reservoir 110 via the reservoir conduit 128, thereby monitoring fluid flow to determine whether leakage may occur through the seals of various components of the brake system 100.

[0034] Brake pedal unit 104 is connected to brake pedal 120 and is actuated by the driver of the vehicle when the driver presses brake pedal 120. Brake sensor or switch 134 may be electrically connected to ECU 114 to provide a signal indicating that brake pedal 120 is depressed. Brake pedal unit 104 may serve as a backup pressurized fluid source to substantially replace the normal supply of pressurized fluid from power transmission unit 108 in certain failure conditions of the braking system and / or during the initial activation of braking system 100. This situation is referred to as a manual push-through event or “manual application”. In the braking system 100 shown and described herein, manual push-through may be achieved for only a pair of wheel brakes 102 (for vehicle weight distribution and weight transfer during braking, typically for a pair of front wheel brakes 102B, 102D) or for all four wheel brakes 102 (i.e., a pair of front wheel brakes 102B, 102D and a pair of rear wheel brakes 102A, 102C).

[0035] The brake pedal unit 104 can supply pressurized fluid to the master cylinder output 136, and then direct the pressurized fluid to the hydraulically operated wheel brakes 102A, 102B, 102C, and 102D as needed. This flow is primarily pushed through the master cylinder 115 by mechanical pressure from the driver's foot on the brake pedal 120. That is, during the manual actuation mode by actuating the brake pedal 120 connected to the master cylinder 115, the master cylinder 115 is operable to generate brake actuation pressure at the first output (here, schematically shown as the master cylinder output 136), thereby hydraulically actuating (in this manual actuation mode) the hydraulically operated brakes (in... Figure 1 The diagram shows and describes a pair of front wheel brakes 102B and 102D.

[0036] As shown, a pair of rear brake motors 138 can be provided to selectively and electrically actuate parking brakes associated with the respective rear wheels. Depending on the need, in addition to parking brakes that may provide electric or hydraulic operation for any of the front and / or rear wheels, wheel brakes 102A, 102B, 102C, and 102D can be electrically and / or hydraulically actuated. For example, front wheel brakes 102B and 102D may be electrically actuated, while rear wheel brakes 102A and 102C may be hydraulically actuated, and / or at least one of wheel brakes 102A, 102B, 102C, and 102D may be electrically actuated during certain operating phases of the same braking system 100 and hydraulically actuated during other operating phases.

[0037] The power transmission unit 108 is configured to selectively supply pressurized hydraulic fluid during braking events to actuate a pair of front wheel brakes 102B and 102D and a pair of rear wheel brakes 102A and 102C. An electronic control unit 114 controls at least one of the power transmission unit 108 and the pair of rear brake motors 138.

[0038] Two-position three-way valve 140 with master cylinder 115 and power transmission unit 108 and as such Figure 1 The front wheel brakes 102B and 102D are shown to be hydraulically connected. A three-way valve 140 selectively controls the hydraulic fluid flowing from a selected one of the master cylinder 115 and the power transmission unit 108 to at least one of the selected wheel brakes 102B and 102D and the selected wheel brakes 102A and 102C of the rear wheel brakes. (For example, Figure 1 It describes "passing by two wheels" or "passing by front wheels", therefore in Figure 1 In this configuration, the three-way valve 140 is connected only fluidly to actuate the front wheel brakes 102B and 102D. In contrast, Figure 4 A three-way valve 140 is shown, fluidly connected for actuating a pair of front wheel brakes 102B and 102D and a pair of rear wheel brakes 102A and 102C in a "four-wheel push-through" configuration.

[0039] By using the three-way valve 140, hydraulic fluid can be directed in a desired manner (from the master cylinder 115 or one of the power transmission units 108) to a selected pair of front wheel brakes 102B / 102D (and / or rear wheel brakes 102A / 102C in some configurations) to assist in power-assisted braking control and provide the desired response time and effective pressure flow to the front wheel brakes 102B and 102D. In other words, the three-way valve 140 is configured to selectively switch the brake system 100 between manual actuation mode and power-assisted braking mode. For cost and packaging reasons, but also to reduce current consumption, a single three-way valve 140 is used here instead of a normally closed valve and a normally open valve. This is primarily due to the fact that a normally open valve requires a high-force spring to prevent it from being hydraulically locked closed in the event of loss of power during power-assisted braking application, which could lead to uncontrolled brake pressure and / or unnecessary braking when the pedal is released.

[0040] Normally closed double-acting plunger (“DAP”) valve 142 is hydraulically located between power transmission unit 108 and three-way valve 140 and at least one of at least one selected pair of wheel brakes (i.e., a pair of front wheel brakes 102B, 102D and / or a pair of rear wheel brakes 102A, 102C).

[0041] Isolation valve 144 and tilt valve 146 are associated with each of the wheel brakes in a pair of front wheel brakes 102B, 102D and a pair of rear wheel brakes 102A, 102C. One or more tilt valves 146 may be normally open, such as those tilt valves used with the rear wheel brakes 102A, 102C in some configurations of the brake system 100. (Isolation valve 144 and tilt valve 146 are marked with the suffixes “A”, “B”, “C” or “D” in the figures to indicate the corresponding wheel brake 102 in the wheel brake 102 associated with each of them.) For the pair of wheel brakes (i.e., a pair of front wheel brakes 102B, 102D and / or a pair of rear wheel brakes 102A, 102C) controlled by the three-way valve 140 to be selectively manually pushed through, the isolation valve 144 is hydraulically located between their respective wheel brakes 102 and the three-way valve 140, and the dump valve 146 is hydraulically located between their respective wheel brakes 102 and the reservoir 110.

[0042] Isolation valves 144B and 144D for a pair of front wheel brakes 102B and 102D can be connected to the power transmission unit 108 via a three-way valve 140, while a pair of rear wheel brakes 102A and 102C bypass the three-way valve 140 to be connected to the power transmission unit 108. This is, for example... Figure 1 The situation shown is only suitable for two-wheeled propulsion operation.

[0043] In contrast, and for example, Figure 4 As shown, isolation valves 144A, 144B, 144C and 144D for a pair of front wheel brakes 102B, 102D and for a pair of rear wheel brakes 102A, 102C are connected to the power transmission unit 108 via a three-way valve 140 for four-wheel push-through operation, as will be discussed below.

[0044] Figure 1 A replenishment check valve 148 is also depicted, which is fluidly located between the reservoir 110 and the power transmission unit 108. When present, the replenishment check valve 148 can be provided to assist in refilling the power transmission unit 108 (or components thereof) under predetermined conditions. For example, when the DAP builds pressure during its retraction stroke (normally closed DAP valve de-energized), the replenishment check valve 148 can help facilitate the refilling of the chamber in front of the DAP head by expelling fluid from the annular chamber behind the DAP head. For example, if additional flow to the brake is required after the DAP has fully advanced its forward stroke, this operation is performed during slip control.

[0045] Now for reference Figure 3 The second configuration of the braking system 100 is depicted, which may be used in part or in whole with other components of the invention as needed. For the sake of brevity, descriptions of similar components and operations elsewhere in this application will not necessarily be repeated for every described configuration or aspect of the braking system 100, but should be regarded as portions of the same reference numerals applicable to other configurations as appropriate.

[0046] exist Figure 3 In the device of the brake system 100 shown, the electronic control module 114 is the first electronic control module 114. Figure 3 The illustrated braking system 100 also includes a second electronic control module 114', which may be the same as or different from the first electronic control module 114. Such a device can be useful, for example, for providing redundancy in the braking system and / or for facilitating autonomous braking. For example, it is conceivable that... Figure 3 The master cylinder 115, brake pedal 120 and related structures, as well as the pedal simulator 106 and related structures shown, can be otherwise omitted from the brake system 100 to achieve a truly autonomous braking device. Another autonomous braking scheme is shown and described, for example, in U.S. Patent Application No. 17 / 188,288 (Attorney's File No. ZF(BEJ)-029439US PRI), filed concurrently with this application and entitled “Apparatus and Method for Control of a Hydraulic Brake System,” which is incorporated herein by reference in its entirety for all purposes.

[0047] exist Figure 3 In the illustrated device, a pair of pumps 150 are controlled by a second electronic control module 114' and powered by a pump motor 152, which can also serve as a pressurized fluid source or replace at least one of the previously discussed master cylinder 115 and power transmission unit 108. One of the selected first electronic control module 114 and the second electronic control module 114' can control the power transmission unit 108, a pair of front wheel brakes 102B and 102D, and a pair of rear wheel brakes 102A and 102C, while the other of the first electronic control module 114 and the second electronic control module 114' can control the rear wheel motors 103A and 103C for use with the parking brakes associated with the rear wheels. As indicated by the dashed line "S", the pumps 150, pump motor 152, and simulator test valve 126 can be... Figure 3 The second electronic control unit 114' in the depicted structure is controlled.

[0048] Optionally, the simulator tests valve 126 and / or brake system 100 in... Figure 3 Any other desired sensors, valves, or other components shown as being controlled by the first electronic control unit 114 can be controlled by the second electronic control module 114' together with the pump 150, pump motor 152, and rear wheel motors 103A and 103C. As shown in the figure, Figure 2 Other components of the braking system 100 and Figure 1 The components shown are basically similar, and this article will not repeat the discussion of these components.

[0049] Turn now Figure 4 The braking system 100 is depicted as being in a third configuration. Figure 4 As previously mentioned, all four wheel brakes 102 are connected to a three-way valve 144 to selectively switch between power transmission unit 108 and manual push-through from master cylinder 115. Figure 4 The master cylinder 115 shown includes an integrated pedal simulator 106.

[0050] Figure 5 The previously described brake system 100 in a fourth configuration is shown, which includes an integrated pedal simulator 106 and a second electronic control unit 114' contained within a housing 116 of a master cylinder 115. As indicated by the dashed line "S", a pump 150, a pump motor 152, and a simulator test valve 126 can be supplied by a... Figure 3 The second electronic control unit 114', as depicted in the diagram, controls the structure. Figure 5 In the brake system 100 shown, all four wheel brakes 102 are connected to a three-way valve 144 to selectively switch between power transmission unit 108 and manual push-through from master cylinder 115.

[0051] Figure 1 and Figure 3 Both depict a first and a second configuration with similar arrangements for providing "front wheel only" manual push-through, with these braking systems 100 having one electronic control unit 114 and two electronic control units 114, respectively. Similarly, Figure 4 and Figure 5 Both depict a third and fourth configuration for providing manual propulsion through “all four wheels”, with the braking systems 100 having one electronic control unit 114 and two electronic control units 114, respectively.

[0052] Turn now Figures 6 to 7 Example fifth and example sixth configurations are shown for providing manual propulsion through "all four wheels," with the braking system 100 having one electronic control unit 114 and two electronic control units 114, respectively. (It is conceivable that those skilled in the art can provide...) Figures 6 to 7 The braking system shown is similar to a braking system designed to provide two-wheel manual pushing through, either a pair of front wheel brakes 102B, 102D or a pair of rear wheel brakes 102A, 102C.

[0053] The description of the brake system 100 will not be repeated. Figures 6 to 7 Description of the components of the brake system 100 shown. Figures 6 to 7 In the fifth and sixth configurations, compared to the first to fourth configurations described previously, the pedal simulator 106 is not integrated into the master cylinder 115. Instead, the pedal simulator 106 is hydraulically separated from the master cylinder 115 via the pedal simulator valve 600.

[0054] Figure 8 A pedal simulator valve 600 is schematically depicted, which is similar to the simulator valve shown and described in U.S. Patent Application No. 17 / 188,152 (Attorney’s File No. ZF(BEJ)-029437US PRI), entitled “Simulator Valve”, filed concurrently with this application and incorporated herein by reference in its entirety for all purposes.

[0055] The pedal simulator valve 600 selectively allows fluid communication between the master cylinder 115 and a separate pedal simulator 106. The simulator valve 600 includes a housing 602 having a central bore 604 extending longitudinally from a first housing surface 606. Figure 8In the orientation, the "longitudinal" direction is substantially perpendicular. Housing 602 includes a pedal simulator channel 608 extending through the housing to at least partially position a central bore 604 in fluid communication with the pedal simulator 106. Housing 602 includes a master cylinder channel 612 extending through the housing to at least partially position the central bore 604 in fluid communication with the master cylinder 115. The master cylinder channel 612 is located longitudinally between the first housing surface 606 and the pedal simulator channel 608.

[0056] Armature 616 is at least partially located within housing 602, in a first armature position and a second armature position (in Figure 6 In the middle, as shown in the second, raised / upper armature position, it selectively reciprocates longitudinally relative to the housing. The lift valve 618 is located within the housing 602 and at least partially within the armature bore 620 of the armature, to selectively reciprocate between the first lift valve position and the second lift valve position (in...). Figure 8 In the middle, (as shown in the second, upper lift valve position) there is selective longitudinal reciprocating motion relative to the armature hole.

[0057] A lift valve 618 defines a first valve 622 that cooperates with at least a portion of a first valve seat 624 of an armature port 620. The lift valve 618 at least partially defines a second valve 628 that is longitudinally spaced from and opposing the first valve seat 624. The second valve 628 includes a second valve seat 630 located within a central port 604 and at least partially spaced from the port wall 632 of the central port 604. The lift valve 618 includes a lift valve port 634 that extends longitudinally through the lift valve 618 and is selectively closed by the first valve 622.

[0058] Armature 616, lift valve 618, and center orifice 604 cooperate to define a damped flow path between them. This damped flow path selectively allows fluid communication through it from master cylinder passage 612 to pedal simulator passage 608. When armature 616 is in the second armature position and lift valve 618 is in the first (lowered) lift valve position, the damped flow path allows fluid communication through it. While this is not... Figure 8 The situation depicted in the figure (in contrast, lift valve 618 is shown raised to the second lift valve position), but the dashed arrow D schematically depicts the approximate damped flow path through pedal simulator valve 600 when the first valve 622 is open.

[0059] Armature 616, lift valve 618, and center orifice 604 also cooperatively define a free fluid path between them, which is defined by... Figure 8As indicated by the solid arrow F in the diagram. The free-flow fluid path selectively allows fluid communication through it from the pedal simulator channel 608 to the master cylinder channel 612. When the armature 616 is in the second armature position and the lift valve 618 is in the second lift valve position, the free-flow fluid path allows fluid communication through it, as shown in the diagram. Figure 8 As shown.

[0060] exist Figures 6 to 7 In the brake system 100 shown, the pedal simulator test valve 126 has been moved upstream of the master cylinder 115. Figures 6 to 7 The pedal simulator valve 600 shown is downstream of the master cylinder 115. For example, such a device can be facilitated by incorporating a leak-proof feature into the simulator test valve 126 instead of the separate bypass valve 148 described previously.

[0061] The pedal simulator 106 is selectively fluidly connected to the master cylinder 115 to provide a predetermined brake pedal response. More specifically, the master cylinder 115 is fluidly connected to the pedal simulator 106 via a master cylinder channel. An input piston 118 is slidably disposed in a bore in the housing 116 of the master cylinder 115. When the brake pedal unit 104 is in its rest position (the driver is not pressing the brake pedal 120), the structure of the master cylinder 115 allows fluid communication between the bore in the housing 116 and the reservoir 110 via a reservoir conduit 128. The pedal simulator 106 is thus selectively fluidly connected to the master cylinder 115 to provide the driver with a predetermined brake pedal 120 response (e.g., brake pedal "feel"). Compared to Figure 1 and Figures 3 to 5 The braking system 100, in Figures 6 to 7 In the braking system 100, it may be easier for the driver to manually push through (requiring less foot pressure) because the driver does not have to push the simulator spring 200 when the pedal simulator 106 is separated from the master cylinder 115.

[0062] The simulated pressure chamber of pedal simulator 106 is in fluid communication with a pedal simulator channel, which in turn is in fluid communication with the master cylinder 115 of brake pedal unit 104. An example of the desired operation of simulator valve 106 is during fault and / or initial / start-up conditions, where brake pedal unit 104 is used to provide a pressurized fluid source to the hydraulically operated wheel brakes 102A, 102B, 102C, and 102D via a push-through manner, as described herein.

[0063] Now for reference Figures 9 to 11 It provides, for example Figure 1 The example operating sequence of the brake system 100 shown comprises three corresponding stages. Specifically, Figures 9 to 11The braking system 100 is shown as having a two-wheel push-through feature (here, push-through to a pair of front wheel brakes 102B, 102D), although those skilled in the art can readily modify the depicted system to facilitate four-wheel push-through braking using any combination of components as shown and described elsewhere herein, for the intended use environment of the invention.

[0064] Figures 9 to 11 The thick lines or solid shaded areas of the structure are under pressure. For example, such as... Figure 9 As shown, master cylinder 115 is under pressure applied from the driver's foot via brake pedal 120. This pressure is pushed through master cylinder output 136 and transmitted through three-way valve 140. Electronic control unit 114 has not yet actuated the motor of power transmission unit 108 to pressurize power transmission unit 108. Front wheel brakes 102B and 102D are also under hydraulic pressure, as... Figure 9 The solid line shading is shown in the image.

[0065] Figures 9 to 11 The dashed lines in the diagram depict components that withstand pressure and fluid flow. For example, such as... Figure 9 As shown, hydraulic fluid flows from the master cylinder output 136 (under pressure, as described above, from the driver's foot on the brake pedal 120) through the three-way valve 140 and into the first pressure circuit (dashed line 1) to power the front wheel brakes 102B and 102D in a manually actuated manner.

[0066] refer to Figure 9 The integrated pedal simulator 106 hydraulically transmits pressure and / or force within the master cylinder 115 to help the driver achieve a comfortable pedal "feel" and reduce pedal travel that would occur without the integrated pedal simulator. A pedal simulator valve 600, similar to the simulator valve shown and described in the aforementioned co-pending patent application serial number No. 17 / 188,152 entitled "Simulator Valve" filed concurrently with this application (Attorney's File No. ZF(BEJ)-029437US PRI), can be used to assist... Figures 9 to 11 The startup sequence shown.

[0067] Turn now Figure 10Ignition is on and braking system 100 is shown in the "transition" phase. Here, power transmission unit 108 is energized and pressure is being built up (as shown in the dark shading in this component). Although hydraulic fluid has not yet traveled to the rear wheel non-push-through wheel brakes 102A, 102C, isolation valves 144A and 144C belonging to the pair of rear wheel brakes 102A, 102C are energized to prevent undesirable transmission of hydraulic fluid to those rear wheel brakes 102A, 102C. As a result, the pair of rear wheel brakes 102A, 102C can be filled in the desired manner. Three-way valve 140 allows pressure within the first pressure circuit 1, such as... Figure 10 The hydraulic lines leading to a pair of front wheel brakes 102B, 102D are shown in bold or thick shaded.

[0068] Finally, refer to Figure 11 The braking system 100 has entered the "assisted" braking application mode. The master cylinder 115 and power transmission unit 108 are under pressure, as are all four wheel brakes 102 (e.g., Figure 11 (Dark shading is shown for all these components). The braking system 100 will remain in place as long as the driver's pressure on the brake pedal 120 indicates a desire to apply assisted braking. Figure 11 The structure shown is as follows.

[0069] Figures 12 to 13 This is a schematic diagram of certain components that can be used with various configurations of the braking system 100, similar to... Figure 2 The integrated pedal simulator 106 and master cylinder 115 and Figure 8 The description and related explanation of the pedal simulator valve 600 in the text.

[0070] Figure 12 A simulator test valve 126 is schematically depicted that can be used with certain implementations of a braking system. Figure 12 The simulator test valve 126 shown includes a body 800 carried by a housing 802. The housing 802 includes a master cylinder passage 804 and a reservoir passage 806. A tappet 808 reciprocates longitudinally within the body 800 under solenoid actuation of an armature 810. Figure 12 In the orientation, the "vertical" direction is basically perpendicular.

[0071] The first end of the push rod 808 is configured to selectively engage a ball 812 carried by the armature 810. A test valve spring 814 biases the push rod 808 away from the ball 812. Figure 12As shown, the test valve spring 814 is inserted longitudinally between the push rod 808 and the ball 812. However, it is conceivable that the ball 812 may alternatively be inserted longitudinally between the test valve spring 814 and the push rod 808. Regardless of the specific design chosen, the test valve spring 814 is inserted according to... Figure 12 The orientation of the push rod 808 towards the engagement with seat 816 pushes the simulator test valve 126 downward to bias it into a closed state. Therefore, Figure 12 The simulator test valve 126 shown can help prevent unintended leakage of the reservoir 110 due to failure or malfunction of the hydraulically driven wheel brakes in wheel brakes 102A, 102B, 102C and / or 102D, and the release of hydraulic fluid to the ground due to such unintended failure.

[0072] Turn now Figure 13 An example configuration of a suitable master cylinder 115 without an integrated pedal simulator 106 is shown. Figure 13 The main cylinder 115 includes a housing 116 defining a longitudinally extending bore 1300. In the orientation of this figure, Figure 13 The longitudinal direction is essentially horizontal. The first spring 1302A and the second spring 1302B extend longitudinally within the bore 1300. The spring guide 1304 is longitudinally and fully inserted between the first spring 1302A and the second spring 1302B. As shown, the spring guide 1304 may have a basic "cup" shape to facilitate hydraulic flow through it during operation of the master cylinder 115. It is conceivable that the spring guide 1304 can... Figure 13 During part of the operation of the main cylinder 115 shown, it reciprocates longitudinally within the bore 1300.

[0073] When present, the spring guide 1304 resists the buckling force of the first spring 1302A and the second spring 1302B during operation of the master cylinder 115. In other words, if the spring guide 1304 is omitted and only a single spring is provided to the bore 1300 (not shown), the single, relatively long spring 1302 will buckle or displace in an undesirable manner during operation. Those skilled in the art will be able to readily provide a spring with… Figure 13 The depicted springs and guides, as well as any other desired features of the master cylinder 115 suitable for assisting in the operation of the master cylinder 115.

[0074] It is conceivable that the parking brakes of the rear wheel brakes 102A and 102C (described herein as electrically actuated) may also be hydraulically actuated instead of electrically actuated. According to the teachings of the present invention, those skilled in the art can facilitate such a device for the rear wheel parking brake by providing suitable hydraulic valves and wiring.

[0075] It is conceivable that components, devices, or any other aspects of the brake system 100 shown and described herein may also or alternatively be used in the brake systems shown and described in U.S. Patent Application No. 17 / 188,227 entitled “Hydraulic Brake Boost” (Attorney’s File No. ZF(BEJ)-029438US PRI), filed concurrently with this application, and / or in U.S. Patent Application No. 17 / 188,288 entitled “Apparatus and Method for Control of a HydraulicBrake System” (Attorney’s File No. ZF(BEJ)-029439US PRI), filed concurrently with this application, all of which are incorporated herein by reference in their entirety for all purposes.

[0076] As used herein, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It will be further understood that, as used herein, the terms “comprising” and / or “including” may specify the presence of the stated feature, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0077] As used herein, the term “and / or” can include any and all combinations of one or more of the associated listed items.

[0078] It will be understood that when an element is referred to as "on another element," "attached to another element," "connected to another element," "joined with another element," "in contact with another element," "adjacent to another element," etc., the element may be directly on, attached to, connected to, joined to, in contact with, or adjacent to the other element, or there may be intermediate elements present. In contrast, when an element is referred to as, for example, "directly on another element," "directly attached to another element," "directly connected to another element," "directly joined to another element," "directly in contact with another element," "directly adjacent to another element," etc., there are no intermediate elements. Those skilled in the art will also understand that references to structures or features "directly adjacent" to another feature arrangement may have overlapping or subordinate portions, while structures or features "adjacent" to another feature arrangement may not have overlapping or subordinate portions.

[0079] Spatial relative terms (such as "below," "under," "lower part," "above," "upper part," "near end," "far end," etc.) may be used herein for the sake of descriptive simplicity to describe the relationship between one element or feature and another element or feature as shown in the figure. It will be understood that, in addition to the orientation depicted in the figure, spatial relative terms may also include different orientations of the device in use or operation. For example, if the device in the figure is inverted, an element described as "below" or "below" other elements or features would be oriented "above" other elements or features.

[0080] As used herein, the phrase "at least one of X and Y" can be interpreted as including X, Y, or a combination of X and Y. For example, if an element is described as having at least one of X and Y, the element may include X, Y, or a combination of X and Y at a given time, and the choice may change from time to time. In contrast, the phrase "at least one of X" can be interpreted as including one or more Xs.

[0081] 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 used only to distinguish one element from another. Therefore, the “first” element discussed below may also be referred to as the “second” element without departing from the teachings of this disclosure. Unless otherwise specifically indicated, the order of operations (or steps) is not limited to the order presented in the claims or figures.

[0082] While various aspects of this disclosure have been specifically shown and described with reference to the examples above, those skilled in the art will understand that various additional aspects can be contemplated. For example, the specific methods of using the described apparatus described above are merely illustrative; those skilled in the art can readily identify any number of tools, sequences of steps, or other means / options for placing the described apparatus or its components in locations substantially similar to those shown and described herein. For the sake of clarity of the figures, certain repeating components shown in the figures are not specifically numbered, but those skilled in the art will recognize the element numbers that should be associated with the unnumbered components based on the numbered components; the presence or absence of element numbers in the figures alone is not intended to distinguish between similar components. Any described structure and component may be integrally formed as a single unit or integral piece or composed of individual sub-components, any of these formations involving any suitable stock or custom components and / or any suitable materials or combinations of materials. Depending on the needs of a particular use environment, any described structure and component may be disposable or reusable. User-perceptible markings can be provided for any component to indicate the material, construction, at least one dimension, etc., associated with that component. These user-perceptible markings potentially help a user select a component from an array of similar components for a specific use environment. A “predetermined” state can be determined at any time before the manipulated structure actually reaches that state; “predetermined” occurs no later than immediately before the structure reaches the predetermined state. The term “substantially” is used herein to mean, to a large extent, but not necessarily entirely, the specified quantity; the “substantially” quantity acknowledges the possibility of including some relatively few non-quantitative items. Although some components described herein are shown to have specific geometries, all structures of this disclosure can have any suitable shape, size, construction, relative relationships, cross-sectional area, or any other physical properties required for a particular application. Any structure or feature described with reference to one aspect or construction can be provided, alone or in combination with other structures or features, to any other aspect or construction, as it is impractical to describe all aspects and constructions discussed herein as having all the options discussed with respect to all other aspects and constructions. Devices or methods incorporating any of these features should be understood to fall within the scope of this disclosure as defined by the following claims and any equivalents.

[0083] Other aspects, objectives, and advantages may be obtained from a study of the accompanying drawings, the disclosure, and the appended claims.

Claims

1. A braking system for selectively actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes, the system comprising: Storage; A master cylinder, which can be operated during manual push mode by actuating a brake pedal connected to the master cylinder to generate brake actuation pressure at a first output end, thereby hydraulically actuating at least one of a pair of front wheel brakes and a pair of rear wheel brakes during the manual push mode. A power transmission unit configured to selectively provide pressurized hydraulic fluid during a braking event, thereby actuating at least one of the pair of front wheel brakes and the pair of rear wheel brakes in a power-assisted braking mode. A pair of rear brake motors, the pair of rear brake motors being used to selectively and electrically actuate the respective left rear wheel parking brake and right rear wheel parking brake; An electronic control unit is provided for controlling at least one of the pair of rear brake motors and the power transmission unit. A pedal simulator, which is in fluid communication with the master cylinder, to provide a predetermined brake pedal response; A two-position three-way valve is hydraulically connected to the master cylinder and the power transmission unit and hydraulically connected to at least one of the pair of front wheel brakes and the pair of rear wheel brakes. The two-position three-way valve selectively controls the flow of hydraulic fluid from one of the master cylinder and the power transmission unit to at least one of the pair of front wheel brakes and the pair of rear wheel brakes; A normally closed DAP valve, the normally closed DAP valve being hydraulically positioned between the power transmission unit and at least one of the two-position three-way valve and at least one of the selected wheel brakes of the pair of front wheel brakes and the pair of rear wheel brakes; as well as An isolation valve and a tilt valve are associated with each of the pair of front wheel brakes and the pair of rear wheel brakes. For at least one selected wheel brake of the pair of front wheel brakes and the pair of rear wheel brakes, the isolation valve is hydraulically positioned between the corresponding wheel brake and the two-position three-way valve, and the tilt valve is hydraulically positioned between the corresponding wheel brake and the reservoir.

2. The braking system according to claim 1, wherein, The two-position three-way valve is configured to selectively switch the braking system between a manual actuation mode and a power-assisted braking mode.

3. The braking system according to claim 1, wherein, The isolation valve for the pair of front wheel brakes is connected to the power transmission unit via the two-position three-way valve, while the pair of rear wheel brakes are connected to the power transmission unit bypassing the two-position three-way valve.

4. The braking system according to claim 1, wherein, The isolation valves for the pair of front wheel brakes and the pair of rear wheel brakes are connected to the power transmission unit via the two-position three-way valves.

5. The braking system of claim 1, wherein the braking system includes a simulator valve that selectively allows fluid communication between the master cylinder and the pedal simulator, the simulator valve comprising: A housing having a central aperture extending longitudinally from a first housing surface, the housing including a pedal simulator channel extending through the housing to at least partially align the central aperture in fluid communication with a pedal simulator, the housing including a master cylinder channel extending through the housing to at least partially align the central aperture in fluid communication with a master cylinder, the master cylinder channel being longitudinally located between the first housing surface and the pedal simulator channel. An armature, at least partially located within the housing, is configured to selectively reciprocate longitudinally relative to the housing between a first armature position and a second armature position. A lift valve, located within the housing and at least partially within an armature bore of the armature, selectively reciprocates longitudinally relative to the armature bore between a first lift valve position and a second lift valve position. The lift valve defines a first valve cooperating with a first valve seat that is at least a portion of the armature bore, and at least partially defines a second valve longitudinally spaced from and opposing the first valve seat. The second valve includes a second valve seat located within the central bore and at least partially spaced from the bore wall of the central bore. The lift valve includes a lift valve orifice extending longitudinally through the lift valve and selectively blocked by the first valve. The armature, the lift valve, and the center orifice cooperate to define a damped flow path between the armature, the lift valve, and the center orifice. This damped flow path selectively allows fluid communication through it from the master cylinder channel to the pedal simulator channel. When the armature is in the second armature position and the lift valve is in the first lift valve position, the damped flow path allows fluid communication through it. The armature, the lift valve, and the center orifice cooperate to define a free-flow fluid path between the armature, the lift valve, and the center orifice. The free-flow fluid path selectively allows fluid communication from the pedal simulator channel to the master cylinder channel through the free-flow fluid path. When the armature is in the second armature position and the lift valve is in the second lift valve position, the free-flow fluid path allows fluid communication through the free-flow fluid path.

6. The braking system according to claim 1, wherein, The pedal simulator is integrated into the master cylinder by being at least partially enclosed within the housing of the master cylinder to form an integrated pedal simulator, which is configured to provide a progressive force-stroke curve for the brake pedal using a plurality of force-responsive springs of the pedal simulator.

7. The braking system according to claim 1, wherein, The master cylinder includes a housing that defines a longitudinally extending bore, a first spring and a second spring extending longitudinally within the bore, and a spring guide longitudinally inserted between the first spring and the second spring, wherein the spring guide resists buckling forces of the first spring and the second spring during operation of the master cylinder.

8. The braking system according to claim 1, wherein, The electronic control unit is a first electronic control module, and the braking system includes a second electronic control module. One of the first electronic control module and the second electronic control module controls the power transmission unit and at least one of the pair of front wheel brakes and the pair of rear wheel brakes, and the other of the first electronic control module and the second electronic control module controls the rear brake motor.

9. The braking system of claim 1, wherein the braking system includes a replenishment check valve located fluidly between the reservoir and the power transmission unit to assist in refilling the power transmission unit under predetermined conditions.

10. The braking system of claim 1, the braking system comprising a simulator test valve fluidly located between the reservoir and the master cylinder, the simulator test valve comprising a test valve spring biasing the simulator test valve toward a closed position.

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