Hydraulic brake booster

Abstract

The present disclosure relates to hydraulic brake assist. A brake system to actuate front and rear wheel brakes includes a reservoir and a master cylinder operable by actuation of a brake pedal connected to the master cylinder to generate a brake actuation pressure at a first output to hydraulically actuate a front wheel brake. A power transfer unit is configured to selectively provide pressurized hydraulic fluid to actuate the front wheel brake. A pair of rear brake motors selectively electrically actuate respective rear wheel brakes. An electronic control unit controls at least one of the rear brake motors and the power transfer unit. A two-position, three-way valve is hydraulically connected to the master cylinder and the power transfer unit and to the front wheel brake. The three-way valve selectively controls hydraulic fluid flow from a selected one of the master cylinder and the power transfer unit to at least one of the front wheel brake.

Description

Technical Field

[0001] This disclosure relates to apparatus and methods for using a braking system, and more specifically, to methods and apparatus for a hydraulic braking system that supplies hydraulic push-through or assistance to the forward brake solely via a two-position three-way valve. 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 for actuating a pair of front wheel brakes and a pair of rear wheel brakes is disclosed. The system includes a reservoir and a master cylinder capable of being operated during manual actuation mode by actuating a brake pedal connected to the master cylinder to generate brake actuation pressure at a first output, thereby hydraulically actuating the pair of front wheel brakes. A power transmission unit is configured to selectively provide pressurized hydraulic fluid during a braking event to actuate the pair of front wheel brakes. A pair of rear brake motors selectively actuate their respective rear wheel brakes electrically. An electronic control unit controls at least one of the pair of rear brake motors and the power transmission unit. A pedal simulator is selectively 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 and the power transmission unit and to the front wheel brakes. The two-position three-way valve selectively controls the flow of hydraulic fluid from a selected one of the master cylinder and the power transmission unit to at least one of the pair of front wheel brakes. 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 yes Figure 1 The braking system is in a schematic hydraulic diagram of the second configuration;

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

[0009] Figure 4 This is a schematic partial side view of a first component suitable for use in a braking system according to any aspect of the invention;

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

[0011] Figure 6 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;

[0012] Figure 7 This is a schematic partial side view of a third component suitable for use in a braking system according to any aspect of the invention;

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

[0014] Figure 9 This is a schematic partial side view of a fifth component suitable for use in a braking system according to any aspect of the invention;

[0015] Figure 10 yes Figure 9 The components are illustrated in a schematic partial side view of the layout structure in the example; and

[0016] Figure 11 yes Figure 3 A schematic hydraulic diagram of the braking system during the second operating phase. Detailed Implementation

[0017] 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.

[0018] The present invention comprises, consists of, or is substantially composed of the following features in any combination thereof.

[0019] Figure 1 A 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 braking 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 may 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 may be housed in one or more blocks or housings. The blocks or housings may 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.

[0020] 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 the master cylinder pressure circuit is associated with providing fluid to the front wheel brakes 102B and 102D. When the rear wheel brakes 102A and 102C are hydraulically operated, or when the rear wheel brakes 102A and 102C can be electrically operated, a second master cylinder pressure circuit (not shown) may be associated with supplying fluid to the rear wheel brakes 102A and 102C, as shown and described herein.

[0021] 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 10 may be configured as a diagonally separated brake system, such that wheel brakes 102A and 102B are associated with wheels at the front or rear axle of the vehicle, and wheel brakes 102C and 102D are associated with wheels at the other axle of the vehicle.

[0022] 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 several internal 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 three 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.

[0023] 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 of wheel brakes 102A, 102B, 102C, and 102D during typical or normal braking application. After braking application, fluid from the hydraulically operated wheel brakes of 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 single-acting plunger assembly. Other configurations of the brake system 100 (not shown) are also contemplated, including hydraulic control of all four wheels, or hydraulic control of the rear wheels instead of the front wheels (where the front wheels would then be electrically controlled / actuated). Based on various aspects of the invention, those skilled in the art will be able to readily provide such an arrangement for the desired operating environment.

[0024] 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.

[0025] 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 in the figures; instead, the walls of a longitudinally extending aperture are schematically illustrated. The housing 116 may be formed as a single unit or comprise two or more separately formed portions joined together. A retainer 118 is connected to the brake pedal 120 via a linkage arm 122. Leftward movement of the retainer 118 may, in certain circumstances, cause an increase in pressure within the master cylinder 115.

[0026] The pedal simulator 106 is selectively fluidly connected to the master cylinder 115 to provide a predetermined brake pedal response. As shown, the pedal simulator 106 is connected to the master cylinder 115 via one or more hydraulic channels, but it is conceivable that "selective fluid connectivity" can be provided by integrating the pedal simulator 106 into the master cylinder 115.

[0027] More specifically, master cylinder 115 is in fluid communication with pedal simulator 106 via master cylinder channel 124. Retaining portion 118 is slidably disposed within a bore in housing 116 of master cylinder 115. When brake pedal unit 104 is in its rest position (driver not pressing brake pedal 120), the structure of master cylinder 115 allows fluid communication between the bore in housing 116 and reservoir 110 via reservoir conduit 128. Pedal simulator 106 is thus selectively in fluid communication with master cylinder 115 to provide the driver with a predetermined brake pedal 120 response (e.g., brake pedal "feel").

[0028] The brake system 100 may also include an optional solenoid-actuated simulator test valve 126, which can be electrically controlled between an open position 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 brake application or for manual actuation mode. The simulator test valve 126 can be actuated to prevent opening at predetermined pressures during various test modes, thereby determining the correct operation of other components of the brake system 100. For example, the simulator test valve 126 can be actuated to a 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 seals of various components of the brake system 100.

[0029] The simulated pressure chamber 130 of the pedal simulator 106 is in fluid communication with the pedal simulator channel 132, which is in fluid communication with the master cylinder 115 of the brake pedal unit 104 via the simulator valve 600 (an example configuration of which is described below). An example of the desired operation of the simulator valve (a known simulator valve or a simulator valve discussed in more detail below as 600) is during fault and / or initial / start-up conditions, in which pressurized fluid is supplied by the brake pedal unit 104 in a push-type manner to the hydraulically operated wheel brakes 102A, 102B, 102C, and 102D, as described herein.

[0030] It is conceivable that the braking system 100 may include at least two hydraulically operated wheel brakes 102A, 102B, 102C, and 102D. For example, two front wheel brakes 102B and 102D, two front wheel brakes 102A and 102C, or any front wheel brake 102B or 102D and a rear wheel brake 102A or 102C may constitute a "pair" of hydraulically operated wheel brakes 102A, 102B, 102C, and 102D. Figure 1 In the following description, a pair of front wheel brakes 102B and 102D are used as examples, although those skilled in the art will be able to provide a suitable braking system 100 according to aspects of the invention for any combination of two or more hydraulically operated wheel brakes 102A, 102B, 102C and 102D.

[0031] Brake pedal unit 104 is connected to brake pedal 120 and is actuated by the driver when the vehicle's driver presses down brake pedal 120. Brake sensor or switch 134 may be electrically connected to ECU 114 to provide a signal indicating that brake pedal 120 has been pressed. 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 the braking system 100. This situation is referred to as a manual push event or "manual application".

[0032] 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 driven from the master cylinder 115 by mechanical pressure from the driver's foot on the brake pedal 120. That is, during the manual push 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 the hydraulically operated brakes.

[0033] As shown in the figure, a pair of rear brake motors 138 may be provided to selectively electrically actuate the respective rear wheel brakes 102A and 102C. Therefore, unless otherwise stated or apparent from the context, it is assumed herein that a pair of front wheel brakes 102B and 102D are hydraulically actuated, and a pair of rear wheel brakes 102A and 102C are electrically actuated, although it is conceivable that wheel brakes 102A, 102B, 102C, and 102D may all be electrically actuated 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. It is also conceivable that, as needed, one or more hydraulically driven and / or electrically driven parking brakes (not shown) can be provided to any wheel of the vehicle. Additionally, it is conceivable that braking signals can be electrically generated by the brake pedal unit 104 via, for example, one or more travel sensors “T” and transmitted to other parts of the braking system 100 in any suitable manner.

[0034] The power transmission unit 108 is configured to selectively provide pressurized hydraulic fluid during braking events to actuate a pair of front wheel brakes 102B and 102D. The electronic control unit 114 controls at least one of a pair of rear brake motors 138 and the power transmission unit 108.

[0035] A two-position three-way valve 140 is hydraulically connected to the master cylinder 115 and the power transmission unit 108, and also hydraulically connected to the front wheel brakes 102B and 102D. The 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 front wheel brakes 102B and 102D. By using the three-way valve 140, hydraulic fluid can be directed to the front wheel brakes 102B and 102D in a desired manner (from the master cylinder 115 or the power transmission unit 108), thereby assisting in brake assist control and providing the desired response time and effective pressure flow to the front wheel brakes 102B and 102D. For cost and packaging reasons, but also to reduce current consumption, a single three-way valve 140 is used here instead of one normally closed valve and one normally open valve. This is primarily due to the fact that normally open valves require an undesirable high-force spring to prevent them from being hydraulically locked closed in the event of loss of power during power-assisted braking application, which could prevent the brake pressure from changing and / or cause unnecessary braking when the pedal is released.

[0036] It is conceivable that at least the three-way valve 140, pedal simulator 106, and power transmission unit 108, along with their associated sensors, hydraulic lines, valves, etc., can be positioned away from the reservoir 112, master cylinder 115, and a pair of front wheel brakes 102B and 102D. Figure 1 The dashed line R in the diagram depicts an example of a component group that can be remotely positioned to free up under-hood space adjacent to the vehicle firewall. The term "remotely positioned" is used herein to mean clearly spaced apart and outside any common housing, such as by placing the component inside the dashed line R in a location within the vehicle separate from the reservoir 110 and master cylinder 115.

[0037] Multiplexing of each of the front wheel brakes in a pair of front wheel brakes 102B and 102D can be provided by an arrangement of a first parallel valve 142 and a second parallel valve 144, respectively. The first parallel valve 142 and the second parallel valve 144 may, for example, be of the type of isolation valve. The first parallel valve 142 and the second parallel valve 144 may be substantially similar to each other in construction, or may include some differences. Those skilled in the art will be able to readily provide suitable first parallel valve 142 and second parallel valve 144 for the intended use environment of the invention.

[0038] Here, for clarity in some of the accompanying drawings, the first parallel valve 142 and the second parallel valve 144 are appended with the letters "B" or "D," referring to the corresponding front wheel brakes 102B and 102D associated with the valves thus labeled. One of the selected first parallel valves 142 and the second parallel valve 144 receives input from the output of the other. When used in a "reverse plumbed" manner as shown in the drawings to provide multiple-way control of the front brakes, the first parallel valve 142 and the second parallel valve 144 are collectively referred to as the multiple-way valve arrangement 146 (again, appended with "B" or "D" when associated with a specific one of the front wheel brakes 102B and 102D).

[0039] The multi-way control facilitated by the multi-way valve arrangement 146 selectively provides, for example, slip control or traction compensation to at least one of a pair of front wheel brakes 102B and 102D. The multi-way control of the front wheel brakes 102B and 102D is provided by an arrangement of a first parallel valve 142 and a second parallel valve 144, wherein a selected one of the first parallel valve 142 and the second parallel valve 144 receives an input from a three-way valve 140 and outputs to a selected one of the pair of front wheel brakes 102B or 102D, and the other of the first parallel valve 142 and the second parallel valve 144 receives an input from a selected one of the pair of front wheel brakes 102B or 102D and outputs to the three-way valve 140. In this way, even if the brake system 100 may include a single pressure source (e.g., power transmission unit 108 and / or master cylinder 115), the fluid pressure at each of the front wheel brakes 102B and 102D can be controlled independently of each other.

[0040] Therefore, the multi-way valve arrangement 146 downstream of the pressure source includes a first parallel valve 142 and a second parallel valve 144, which are controlled between their open and closed positions to provide different braking pressures within the front wheel brakes 102B and 102D as needed for specific braking conditions. The multi-way valve arrangement 146 and / or other valves of the braking system 100 (any of which may be solenoid-operated and have any suitable configuration) can be used to assist in providing controlled braking operation, such as, but not limited to, ABS, traction control, vehicle stability control, dynamic rear proportioning, regenerative braking hybridization, and automatic braking.

[0041] Figure 1A bypass valve 148, including a check valve, is also depicted fluidically positioned between the three-way valve 140 and the master cylinder 115. (This could also result in the bypass valve 148 fluidly positioned between the three-way valve 140 and the pedal simulator 106). The bypass valve 148 (when present) can be provided to assist in system leakage (i.e., undesirable fluid pressure loss within the brake system 100 and potential fluid loss from the reservoir 110 and / or from the master cylinder 115) in the event of a failure of one or more of the hydraulically actuated wheel brakes in the front and rear wheel brakes 102A, 102B, 102C, and 102D, allowing hydraulic fluid to be released outside the brake system. The opening pressure of the pressure relief valve 148 can be determined for the specific operating environment of the brake system 100 to ensure the desired continued availability of the assist function even after such a failure (possibly by isolating the failed brake). Therefore, when at least one front wheel brake 102B or 102D is in a fault condition that releases fluid to the ground, the bypass valve 148 prevents fluid from flowing out. Figure 1 and Figure 2 The storage 110 and / or master cylinder 115 in the arrangement structure depicted are released.

[0042] Now for reference Figure 2 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 need to be repeated for every described configuration or aspect of the braking system 100, but should instead be applied, as appropriate, to portions of the same reference numerals in other configurations. Figure 2 In the arrangement of the brake system 100 shown, the electronic control module 114 is the first electronic control module 114. Figure 2 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. This arrangement 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 2The 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 brake arrangement. 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.

[0043] exist Figure 2 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, serving as a pressurized fluid source or replacing 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 and a pair of front wheel brakes 102B and 102D, while the other of the first electronic control module 114 and the second electronic control module 114' can control a pair of rear wheel brakes 102A and 102C. Optionally, simulator test valve 126 and / or any other desired sensors, valves, or other components of the brake system 100 can be controlled by the second electronic control module 114' along with the pumps 150, pump motor 152, and rear wheel brakes 102A and 102C. 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.

[0044] Turn now Figure 3 The braking system 100 is depicted as being in a third configuration. Figure 3 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 4 The arrangement is illustrated schematically. The integrated pedal simulator 106 is configured to provide a progressive force-stroke curve for the brake pedal 120 using multiple force-responsive springs with similar or different spring forces of any desired degree. Two different force-responsive springs, 400A and 400B, are shown and described herein with respect to the pedal simulator 106. Figure 4As shown, the integrated pedal simulator includes a resilient stop 402 against which a round-end piston 404 presses to cushion the impact of the piston 404 during operation of the pedal simulator 106 portion of the master cylinder 115. The piston 404 is directly connected to the connecting rod arm 122 via a retainer 118. A spring retainer 406 maintains the position of the low-resistance responsive spring 400A, as shown.

[0045] During use, the driver is Figure 4 The upward orientation of the brake pedal 120 forces the linkage arm 122 to the left. The low-resistance responsive spring 400A resists the pushing force until it is compressed until the piston 404 directly or indirectly contacts the far right (in...). Figure 4 The spring retainer 406 is positioned at a point on its surface. Once this contact is established, the spring retainer 406 moves in coordination with the linkage arm 118 to further compress the higher resistance force within the housing 116 in response to the spring 400B 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 piston 404 contacts the resilient stop 402, this bent or spherical surface helps to distribute the compressive force onto the resilient stop 402 and avoids a jerky, sudden contact with the resilient stop 402, which the driver might find unpleasant and mimic the bouncing sensation of a vacuum booster.

[0046] 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 2 The second electronic control unit 114', as depicted in the diagram, controls the structure. (Here, as shown in...) Figure 3 In the brake system 100 shown, the pedal simulator valve 600 and the pedal simulator test valve 126 have been moved upstream of the master cylinder 115. This arrangement can be facilitated, for example, by incorporating a leak-proof feature into the simulator test valve 126 instead of the separate bypass valve 148 described previously.

[0047] Figures 6 to 10 This is a schematic diagram of certain components that can be used with various configurations of the braking system 100, similar to... Figure 4 Description of the integrated pedal simulator 106 and master cylinder 115. For example, Figure 6A 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), which was filed concurrently with this application and is entitled “Simulator Valve” and is incorporated herein by reference in its entirety for all purposes.

[0048] 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 6 In the orientation, the "longitudinal" direction is substantially vertical. 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.

[0049] 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 6 In the middle, (as shown in the second, upper lift valve position) there is selective longitudinal reciprocating motion relative to the armature hole.

[0050] 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 blocked by the first valve 622.

[0051] 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 6 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.

[0052] Armature 616, lift valve 618, and center orifice 604 also cooperatively define a free fluid path between them, which is defined by... Figure 6 As 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 6 As shown.

[0053] Turn now Figure 7 An example configuration of a suitable master cylinder 115 without an integrated pedal simulator 106 is shown. Figure 7 The master cylinder 115 includes a housing 116 that defines a longitudinally extending bore 700. Figure 7 The "longitudinal" direction in the figure is substantially horizontal and is the orientation shown in the diagram. The first spring 702A and the second spring 702B extend longitudinally within the bore 700. A spring guide 704 is longitudinally and fully inserted between the first spring 702A and the second spring 702B. As shown, the spring guide 704 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 704 can... Figure 7 During part of the operation of the main cylinder 115 shown, it reciprocates longitudinally within the bore 700.

[0054] Spring guide 704 (when present) resists the buckling force of the first spring 702A and the second spring 702B during operation of the master cylinder 115. In other words, if spring guide 704 is omitted and only a single spring is supplied to bore 700 (not shown), the single, relatively long spring 702 will buckle or displace in an undesirable manner during operation. Those skilled in the art will be able to readily provide springs with… Figure 7The depicted spring and guide arrangement structure, as well as any other desired features of the master cylinder 115 suitable for assisting in the operation of the master cylinder 115.

[0055] Figure 8 A simulator test valve 126 is schematically depicted that can be used with certain implementations of a braking system. Figure 8 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 8 In the orientation, the "vertical" direction is basically perpendicular.

[0056] 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. (As...) Figure 8 As 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 8 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 8 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.

[0057] Figure 9 An isolation valve 900 is schematically depicted, which can be either a first parallel valve 142 or a second parallel valve 144. Here, the isolation valve 900 includes multiple components that may be similar to those shown and depicted with respect to the simulator test valve 126 discussed above. A housing 902 carries a body 904. The housing 904 includes a first channel 906 and a second channel 908. The first channel 906 is for fluid communication with a pressure source (e.g., master cylinder 115 and / or power transmission unit 108) and a corresponding wheel brake 102A, 102B, 102C, or 102D, and the second channel 908 facilitates fluid communication with the other of the pressure source and the corresponding wheel brake. A tappet 910 reciprocates longitudinally within the body 904 under the influence of an armature 912, which may be solenoid-driven. Figure 9 In its orientation, the "longitudinal" direction is essentially perpendicular. Valve spring 914 is arranged according to... Figure 9The orientation of the valve spring 914 biases the push rod 910 upwards, engaging it with the ball 916 carried by the armature 912. Therefore, the push rod 910 is biased away from the seat 918 by the valve spring 914. Figure 9 The isolation valve 900 will tend to open when power is off.

[0058] Figure 10 The arrangement of two isolation valves 900 is schematically shown, each isolation valve being substantially similar to... Figure 9 The isolation valve shown. Figure 10 In this diagram, the isolation valves are described as a first parallel valve 142 and a second parallel valve 144 assembled into a multi-way valve arrangement 146. The first parallel valve 142 and the second parallel valve 144 are each typically operable to two positions, as schematically shown in the figure.

[0059] Existing multi-way valves often fall into either the "pressure-balanced" or "brute-force" type. These existing valves are often expensive to manufacture (requiring specialized parts not used in other similar valves in the system) and may require unnecessarily high currents to operate individual valves correctly. In contrast, Figure 10 The schematically depicted multi-way valve arrangement 146 includes two valves, each with its own coil for operation. The pressures across the first parallel valve 142 and the second parallel valve 144 are equal, and the total current consumption required to power the solenoids of these two valves is lower than the current consumption required for a single multi-way valve as taught in the prior art. Furthermore, due to the modular nature of the multi-way valve arrangement 146, the first parallel valve 142 and the second parallel valve 144 according to various aspects of the invention can be replaced individually, saving cost and time, rather than requiring the replacement of the entire single-piece multi-way valve in case of failure.

[0060] The first parallel valve 142 and the second parallel valve 144 are "reversely vertical" to Figure 10 In the multi-way valve arrangement 146 shown, that is, one of the selected first parallel valve 142 and the second parallel valve 144 receives input from the output of the other of the first parallel valve 142 and the second parallel valve 144. Figure 10The configuration is schematically depicted using a first multiplexer 920 (which connects the first channel 906' of the first parallel valve 142 to the second channel 908' of the second parallel valve 144) and a second multiplexer 922 (which connects the first channel 906' of the second parallel valve 144 to the second channel 908' of the first parallel valve 142). In this way, if a pressure difference exists across the first parallel valve 142 and the second parallel valve 144, one of the valves will always be open when de-energized. This is true even when relatively low-force springs are used in the first and second parallel valves 142 and 144. After one of the selected parallel valves 142 and 144 is opened, if the pressure difference across the valve is allowed to drop below a certain amount based on plunger control, the other parallel valve 142 and 144 will open. This assumes that the coils of both the first and second parallel valves 142 and 144 are controlled substantially similarly.

[0061] It is conceivable that in some operating environments, separate control of the coil can be selectively employed. For example, with the first parallel valve 142 and the second parallel valve 144 energized and closed, the plunger can be controlled to a pressure greater than the brake pressure. One of the selected parallel valves 142 and 144 (oriented such that pressure attempts to keep the valve closed) can remain energized, while the other can be temporarily de-energized, allowing the pressures across the first and second parallel valves 142 and 144 to be unbalanced when fluid is applied to the brake. This type of control can also be achieved using conventional valve control if, based on its sealing diameter, spring force, any aerodynamic forces on the tappet, or any other desired factor, the pressure across the selected parallel valve 142 and 144 (where pressure attempts to keep the valve closed) does not drop below a certain amount.

[0062] Figure 11 A schematic depiction of... Figure 3 The brake system shown is basically similar to brake system 100. However, in Figure 11 In this process, the braking system 100 has been actuated to a power-assisted braking state or configuration. Figure 11 The thick lines or solid shaded portions of the structure are under pressure. For example, the master cylinder 115 is under pressure applied from the driver's foot via the brake pedal 120. This pressure pushes the master cylinder output 136 and holds it at the three-way valve 140. The electronic control unit 114 has actuated the motor of the power transmission unit 108, thereby placing the power transmission unit 108 under pressure. The electronic control unit 114 also actuates the rear brake motor 138 to apply the rear wheel brakes 102A and 102C. The front wheel brakes 102B and 102D are also under hydraulic pressure, such as... Figure 11The solid line shading is shown in the image.

[0063] Figure 11 The dashed lines in the diagram depict components that bear pressure and fluid flow. For example, hydraulic fluid flows from the power transmission unit output 1100 through the three-way valve 140 and into the multi-way valve arrangement structures 146B and 146D to power the front wheel brakes 102B and 102D in an assisted manner.

[0064] exist Figure 11 In the arrangement, if traction control or some other type of individual actuation of the front wheel brakes 102B and 102D is desired, the first parallel valve 142 and the second parallel valve 144 of one or both of the multi-way valve arrangements 146B and 146D will be controlled by the electronic control unit 114 to achieve the desired transfer of hydraulic fluid to or from the corresponding front wheel brakes 102B or 102D. Due to the relatively high responsiveness and robustness of the first parallel valve 142 and the second parallel valve 144, such individual control can be performed in a very flexible and accurate manner to achieve the desired performance of the brake system 100.

[0065] It is conceivable that the rear wheel brakes 102A and 102C (described herein as electrically actuated) may also be, or alternatively, hydraulically actuated instead of electrically actuated. Based on the teachings of the present invention, those skilled in the art can facilitate this arrangement of the rear wheel brakes 102A and 102C by providing suitable hydraulic valves and wiring.

[0066] It is conceivable that components, arrangements, 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 / 188,363 (Attorney's File No. ZF(BEJ)-030117US PRI), co-filed with this application entitled “Apparatus and Method for Control of a Hydraulic Brake System”, and / or in U.S. Patent Application No. 17 / 188,288 (Attorney's File No. ZF(BEJ)-029439US PRI), co-filed with this application entitled “Apparatus and Method for Control of a Hydraulic Brake System”, which are incorporated herein by reference in their entirety for all purposes.

[0067] 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.

[0068] As used herein, the term “and / or” can include any and all combinations of one or more of the associated listed items.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 actuating a pair of front wheel brakes and a pair of rear wheel brakes, the system comprising: Storage; The master cylinder is operable 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 the pair of front wheel brakes. A power transmission unit configured to selectively provide pressurized hydraulic fluid during a braking event to actuate the pair of front wheel brakes; A pair of rear brake motors, the pair of rear brake motors being used to selectively and electrically actuate the respective rear wheel brakes; 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 selectively fluidly connected to the master cylinder to provide a predetermined brake pedal response; as well as A two-position three-way valve is hydraulically connected to the master cylinder and the power transmission unit, and hydraulically connected to the front wheel brake. The two-position three-way valve selectively controls the flow of hydraulic fluid from a selected one of the master cylinder and the power transmission unit to at least one of the pair of front wheel brakes. The multiplexing of each front wheel brake in the pair of front wheel brakes is provided by an arrangement of a first parallel valve and a second parallel valve, wherein either the first parallel valve or the second parallel valve receives an input from the output of the other of the first parallel valve and the second parallel valve, and wherein the first parallel valve and the second parallel valve tend to open when de-energized and close when energized.

2. The braking system according to claim 1, wherein, The first parallel valve and the second parallel valve are basically similar in construction to each other.

3. The braking system according to claim 1, wherein, The multiplexing control selectively provides slip control to at least one of the pair of front wheel brakes.

4. The braking system according to claim 1, wherein, One of the first parallel valve and the second parallel valve receives an input from the two-position three-way valve and outputs the received input from the two-position three-way valve to one of the pair of front wheel brakes; the other of the first parallel valve and the second parallel valve receives an input from one of the pair of front wheel brakes and outputs the received input from one of the pair of front wheel brakes to the two-position three-way valve.

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 path between the armature, the lift valve, and the center orifice. The free flow path selectively allows fluid communication from the pedal simulator channel to the master cylinder channel through the free flow path. When the armature is in the second armature position and the lift valve is in the second lift valve position, the free flow path allows fluid communication through the free flow 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 module is a first electronic control module, and the braking system includes a second electronic control module, wherein one of the first electronic control module and the second electronic control module controls the power transmission unit and the pair of front wheel brakes, and the other of the first electronic control module and the second electronic control module controls the pair of rear wheel brakes.

9. The braking system of claim 1, wherein the braking system includes a bypass valve fluidly positioned between the three-way valve and the pedal simulator to prevent fluid release from the reservoir when at least one front wheel brake is in a fault condition that releases fluid to the ground.

10. The braking system according to claim 1, wherein, The three-way valve, the pedal simulator, and the power transmission unit are positioned away from the master cylinder, the reservoir, and the pair of front wheel brakes.

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

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