BRAKING SYSTEM FOR A VEHICLE

Abstract

Braking system for a vehicle, comprising: a pedal (101) to which a brake input is applied; an actuator part configured to generate a brake hydraulic pressure in response to the brake input applied to the pedal (101), and comprising a first actuator with a first hydraulic chamber (131) and a second actuator with a second hydraulic chamber (132); Wheel brakes (136, 137) connected to the first actuator and the second actuator; and an auxiliary cylinder (105) with two auxiliary pistons (108, 109) for forming a third hydraulic chamber (106) and a fourth hydraulic chamber (107), which are two hydraulic chambers that are continuously arranged in a housing; wherein the auxiliary cylinder (105) has a first centrally arranged auxiliary piston and a second auxiliary piston connected to the pedal (101), and wherein the first hydraulic chamber (131) is connected to the third hydraulic chamber (106) by a flow path (112, 121) in which a first valve (119) is installed, the second hydraulic chamber (132) is connected to the fourth hydraulic chamber (107) by a flow path (122, 115) in which a second valve (120) is installed, and pressure equalization is performed by the auxiliary cylinder when a difference occurs between the hydraulic brake pressures generated by the first actuator and the second actuator, wherein the fourth hydraulic chamber (107) is connected to a first flow path (115) adjacent to the first auxiliary piston (108) and to a second flow path (116), and wherein the first flow path (115) and the second flow path (116) are connected to the second valve (120), wherein the first auxiliary piston (108) separates the third hydraulic chamber (106) and the fourth hydraulic chamber (107), and wherein, when the flow path through the first auxiliary piston (108) is closed by the pressure difference between the third hydraulic chamber (106) and the fourth hydraulic chamber (107), the braking force is transmitted through the second flow path (116) to the second hydraulic chamber (132).

Description

BACKGROUND OF THE INVENTION Technical field

[0001] The present invention relates to a braking system for a vehicle and in particular to a braking system for a vehicle that can independently control the braking force of the vehicle wheels. Description of the state of the art

[0002] Recently, a brake-by-wire technology, which controls the vehicle's braking through an electronic control system, was developed for a vehicle's braking system instead of a conventional general hydraulic pressure control system. In such an electronically controlled braking system, the required hydraulic pressure is generated using an electric motor based on the driver's braking request, and the braking force is produced by transferring the hydraulic pressure generated by driving the motor to the wheel brake (wheel cylinder) of each wheel.

[0003] The electronic brake control system, which adjusts hydraulic pressure using an electronic actuator, is commonly referred to as an electro-hydraulic brake system (EHB), i.e., an electronic hydraulic pressure brake system. The electronic hydraulic pressure brake system is capable of individually adjusting the braking force generated at each wheel. This allows for the implementation of functions such as electronic stability control (ESC) or anti-lock braking system (ABS). In a conventional electronic hydraulic pressure brake system, a pump with a motor is used as the aforementioned electronic actuator. When the motor is driven, a piston in this system moves back and forth, forcing brake fluid into the chamber of a cylinder to generate hydraulic pressure.

[0004] Furthermore, in the electronic hydraulic pressure brake system, after the pedal travel is detected by a sensor, the braking force of each wheel is adjusted by the hydraulic pressure generated by the pump via the engine drive. Additionally, the electronic hydraulic pressure brake system incorporates a pedal simulator that allows the driver to feel the same pedal pressure as in a conventional hydraulic pressure brake system. When the driver depresses a pedal connected to a backup master cylinder, the hydraulic pressure of the brake fluid in the backup master cylinder increases, and this pressure is transmitted via a pedal hydraulic pressure line to the pedal simulator to create a pedal feel.

[0005] When the driver depresses the brake pedal, a control unit calculates a target hydraulic pressure requested by the driver based on a driver pedal input value (e.g., a brake input value) detected using a brake pedal sensor (e.g., a pedal travel sensor), such as a pedal stroke value. The control unit then adjusts the motor's drive based on the calculated target hydraulic pressure to generate hydraulic pressure in the pump. This hydraulic pressure is then transmitted to each wheel cylinder to provide the desired braking force.

[0006] A prior art technology discloses a braking system with a main motor for operating four wheels in normal operation and a plurality of valves installed on hydraulic pressure lines at each wheel. In particular, an auxiliary motor is provided to respond to a fault if the main motor fails. However, the auxiliary motor only operates in the event of a fault, which can affect vehicle weight and production costs.

[0007] The above information disclosed in this section is intended only to improve the understanding of the background of the invention and may therefore contain information that does not constitute the prior art already known to a person skilled in the art in this country.

[0008] DE 10 2017 215 704 A1 constitutes subsequently published prior art, which is only to be used for the examination of novelty, but not inventive step. PRESENTATION OF THE INVENTION

[0009] The present invention provides a braking system for a vehicle that is capable of simplifying the braking system structure with a plurality of valve elements and independently adjusting the brake pressure of each wheel. Furthermore, the present invention provides a braking system for a vehicle that is designed to prevent unexpected pre-tensioning during rapid braking, thereby improving the vehicle's straight-line stability. Additionally, the present invention provides a braking system for a vehicle that features a fail-safe mode capable of effectively responding to various fault situations. This means maintaining the vehicle's straight-line stability by preventing unexpected pre-tensioning during rapid braking.

[0010] The invention is defined by claim 1.

[0011] To achieve the above objective, an exemplary embodiment of the present invention may include a pedal to which a brake input is applied; an actuator configured to generate brake hydraulic pressure in response to the brake input applied to the pedal, comprising a first actuator with a first hydraulic chamber and a second actuator with a second hydraulic chamber; wheel brakes connected to the first actuator and the second actuator; and an auxiliary cylinder with two auxiliary pistons for forming a third hydraulic chamber and a fourth hydraulic chamber, the two hydraulic chambers being continuously arranged in a housing.

[0012] The auxiliary cylinder can have a first, centrally located auxiliary piston and a second auxiliary piston connected to the pedal. The first hydraulic chamber can be connected to the third hydraulic chamber by a flow path in which a first valve is installed, and the second hydraulic chamber can be connected to the fourth hydraulic chamber by a flow path in which a second valve is installed. Pressure equalization can be carried out by the auxiliary cylinder when a difference is generated between the hydraulic brake pressures produced by the first actuator and the second actuator.

[0013] According to an exemplary embodiment of the present invention, since the brake pressure of each wheel can be adjusted independently of two motors, the independent control performance for each wheel for ABS and ESC control, and so on, can be improved. Furthermore, according to the present invention, it may be possible to distribute the pressure evenly between the left and right wheels, while simplifying the design of the braking system. As a result, it may be possible to improve the straight-line stability of the vehicle by fundamentally preventing pre-tensioning of the brakes, which can occur during rapid braking.

[0014] Furthermore, according to an exemplary embodiment of the present invention, it is possible to control the braking of both the left and right wheels with the remaining actuators, even if one of the actuators generating the brake pressure fails, thus improving the robustness of the braking system. Even if a line of the hydraulic pressure line is interrupted, it may be possible to perform the brake control completely separately with the interrupted line in order to prevent a loss of performance, even if the line is interrupted. BRIEF DESCRIPTION OF THE FIGURES

[0015] The above and other features of the present invention will now be described in detail with reference to exemplary embodiments thereof, which are shown in the accompanying drawings, which are shown below for illustrative purposes only and thus do not limit the present invention, wherein: Fig. 1 schematically shows the design of a braking system for a vehicle according to an exemplary embodiment of the present invention; Fig. 2A shows an auxiliary cylinder connected to a pedal and left and right hydraulic pressure lines connected to it in a front wheel brake module according to an exemplary embodiment of the present invention, where the pressure equalization is carried out by the auxiliary cylinder when the pressure on a left wheel is high; Fig. Figure 2B according to an exemplary embodiment of the present invention shows that pressure equalization is carried out by the auxiliary cylinder when the pressure on a right wheel is high; Fig. Figure 2C, according to an exemplary embodiment of the present invention, illustrates that emergency braking is performed by a pedal force when an electrical fault occurs; Fig. 3A according to an exemplary embodiment of the present invention shows an initial state of the braking system for a vehicle before braking; Fig. 3B shows the operation of the vehicle's braking system during normal braking according to an exemplary embodiment of the present invention; Fig. 3C shows a state in which the left and right braking forces are uniformly reduced during rapid braking according to an exemplary embodiment of the present invention; Fig. Figure 3D shows that independent control is applied to the left and right wheels during ABS or ESC control according to an exemplary embodiment of the present invention; Fig. Figure 3E shows that braking is performed when the actuator fails according to an exemplary embodiment of the present invention; Fig. Figure 3F shows that braking is carried out when, according to an exemplary embodiment of the present invention, a certain line break occurs; Fig. 3G shows a state in which backup braking is performed solely by pedal force due to an electrical fault generation according to an exemplary embodiment of the present invention; and Fig. 4 shows a braking system for a vehicle according to a further embodiment of the present invention.

[0016] It is understood that the accompanying drawings are not necessarily to scale and represent a somewhat simplified depiction of various features illustrating the basic principles of the invention. The specific design features of the present invention, as disclosed herein, including, for example, certain dimensions, orientations, positions, and shapes, are partly determined by the intended application and environment of use. In the figures, reference numerals refer to the same or equivalent parts of the present invention in the various figures of the drawing. DETAILED DESCRIPTION OF THE PREFERRED VERSION

[0017] It is understood that the term "vehicle" or "conveyor" or any other similar term as used herein includes motor vehicles in general, such as passenger cars including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft and the like, including hybrid vehicles, electric vehicles, internal combustion engine vehicles, plug-in hybrid electric vehicles, hydrogen vehicles and other vehicles using alternative fuels (e.g., fuels derived from sources other than petroleum).

[0018] Although one exemplary embodiment is described as using a plurality of units to execute the exemplary process, it is understood that the exemplary processes can also be executed by one or more modules. Furthermore, it is understood that the term controller / control unit refers to a hardware device comprising memory and a processor. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more processes, which are described below.

[0019] The terminology used herein serves only to describe certain embodiments and is not intended to limit the invention. As used herein, the singular forms "a," "an," "one," and "the" are intended to include the plural unless the context clearly indicates otherwise. It is further understood that the expressions "possess" and / or "possessing," when used in this description, indicate the presence of the specified features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" indicates one or all combinations of one or more of the associated listed elements.

[0020] The following section refers in detail to various exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention is described in connection with exemplary embodiments, it is understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments but also various alternatives, modifications, equivalents, and other embodiments that may be included in the spirit and scope of the invention, as defined by the accompanying claims.

[0021] Fig. Figure 1 shows a braking system for a vehicle according to an exemplary embodiment of the present invention, which has a front wheel brake module connected to a pedal and designed to be braked by two actuators each.

[0022] In the embodiment of Fig. 1. A hydraulic pressure brake driven by an actuator can be installed on the front wheels, and an electronic brake operating based on a pedal sensor output can be arranged on the rear wheels. Since the hydraulic pressure brake of the front wheels can generate hydraulic pressure via two actuators, the left and right front wheels can be actuated independently of each other. Furthermore, since the rear wheels can be equipped with wheel brakes 138 and 139 formed by the electronic brake, in the exemplary embodiment of Fig. 1. All four wheels can be operated independently of each other.

[0023] On the other hand, according to the present invention, either the front wheels or the rear wheels should consist of a hydraulic pressure brake, and the hydraulic pressure brake should consist of a brake module which is braked by hydraulic pressure with two actuators. Fig. Figure 1 shows an embodiment in which the front wheels are braked by hydraulic pressure. In contrast to Fig. 1. The rear wheels can be braked by hydraulic pressure, and the front wheels can be braked by the electronic brake.

[0024] The following description of the present invention is based on an example in which the brake module for the front wheels is a hydraulic pressure brake driven by two actuators. However, those skilled in the art will recognize that the present invention is not limited to this exemplary embodiment and that it can be applied equally to an example of the brake module for the rear wheels configured for the hydraulic pressure brake. Accordingly, the present invention should not be considered limited to the accompanying drawings and examples, but is intended to include various modifications.

[0025] Referring to Fig. 1. The brake module for the front wheels can be an electronic hydraulic pressure brake system driven by two actuators. The brake module for the front wheels can be connected to a pedal 101, which is designed to receive the driver's brake input, that is, the input by the driver pressing the pedal.

[0026] The front wheel brake module can feature a pedal simulator 103, which allows the driver to feel the same pedal pressure as with a conventional hydraulic pressure brake. As in Fig. As shown in Figure 1, the pedal 101 (e.g., the pedal shaft) can be connected to a piston rod 102, and the piston rod 102 can be connected to the pedal simulator 103. Accordingly, when the driver engages or presses the pedal, the piston rod 102 can move backward, and the driver can experience a pedal sensation by actuating the pedal simulator 103.

[0027] Furthermore, a pedal sensor 104, designed to detect the brake input from the pedal 101, can also be installed in the brake system. The pedal sensor 104 can be designed to detect the driver's pedal travel and operate the brake system based on the detected pedal travel. In particular, a controller 135 can be designed to receive a signal for the pedal input, i.e., the pedal sensor output, and to adapt the relevant configurations to generate a target braking force based on the output signal. The controller 135 can be designed to operate the hydraulic pressure brake or the electronic brake. Thus, the controller 135 can be designed to receive the pedal sensor output, actuate the actuator for each wheel, and brake each wheel with the generated braking force.

[0028] In this respect, the exemplary embodiment of the present invention can be configured to have two actuators for independently driving the left and right wheels of the front wheels. The actuator in the present invention can have a drive source configured to supply each wheel with the appropriate hydraulic pressure. The exemplary embodiment of the present invention can have a cylinder and a piston forming a hydraulic chamber, and a motor configured to move the piston to pressurize the fluid. However, the configuration of the actuator is not limited to the example mentioned above and can be modified into a suitable structure for driving the hydraulic pressure brake.

[0029] As in Fig. As shown in Figure 1, an exemplary embodiment of the present invention can have an actuator for the left wheel and an actuator for the right wheel. A first actuator for the left wheel can have a first main piston 127 and a first main cylinder 125 for forming a first hydraulic chamber 131, and a first motor 129 for driving the first main piston 127. The second actuator for the right wheel can also have a second main piston 128, a second main cylinder 126 to form a second hydraulic chamber 132, and a second motor 130 in the same configuration as for the left wheel.

[0030] The first hydraulic chamber 131 can be connected to the side of a wheel brake section 136 of the left wheel via a flow path 123 formed on a first side and to an auxiliary cylinder 105 via a flow path 121 connected to a second side. Similarly, the second hydraulic chamber 132 can be connected to the side of a wheel brake section 137 of the right wheel via a flow path 124 formed on a first side and can be connected to the side of the auxiliary cylinder 105 via a flow path 122 connected to a second side.

[0031] The auxiliary cylinder 105 and the first hydraulic chamber 131 can be connected by flow paths 112 and 121, and the flow paths 112 and 121 can be configured to be opened or closed by a first valve 119. A second valve 120 can also be installed in flow paths 115, 116, and 122 that connect the auxiliary cylinder 105 and the second hydraulic chamber 132. The first hydraulic chamber 131 and the second hydraulic chamber 132 can be selectively separated by the first valve 119 and the second valve 120. A normally open valve can be used as the first valve 119 and the second valve 120. The functions of this first valve 119 and the second valve 120 are described below. Fig. Sections 3A to 3B are described in more detail.

[0032] The auxiliary cylinder 105 can have two auxiliary pistons 108 and 109 for forming two hydraulic chambers arranged continuously. The two hydraulic chambers formed in the auxiliary cylinder, i.e., a third hydraulic chamber 106 and a fourth hydraulic chamber 107, can each be connected to one side of the reservoir 133 via flow paths 113 and 114. The two auxiliary pistons 108 and 109 in the auxiliary cylinder 105 can be designed to be movable in the longitudinal direction within the auxiliary cylinder 105. When the two auxiliary pistons 108 and 109 move, the flow path connected to the reservoir 133 can be blocked. In other words, as in Fig. As shown in Figure 1, the auxiliary pistons 108 and 109 can have a piston head of a predetermined length extending along the inner wall of the auxiliary cylinder 105. When the auxiliary pistons 108 and 109 are arranged in the correctly aligned positions, the outer surfaces of the piston heads can block the flow path connected to the side of the reservoir 133. Furthermore, a return line 134 can also be provided for the fluid flowing back to the reservoir 133.

[0033] The reservoir 133 can have a third valve 117 and a fourth valve 118 for opening or closing the flow path connected to the third hydraulic chamber 106 and the fourth hydraulic chamber 107. The third valve 117 and the fourth valve 118 can be open to connect the reservoir side to the auxiliary cylinder 105 before braking and be closed during braking. Additionally, the third valve 117 and the fourth valve 118 can both be normally open. The return springs 110 and 111 can be located in the third hydraulic chamber 106 and the fourth hydraulic chamber 107, respectively, and can determine the initial position of the auxiliary pistons in the pre-braking state. These return springs 110 and 111 can be designed to provide restoring forces for returning to an initial position, even if the auxiliary pistons move due to a pressure equalization process or the like.

[0034] The auxiliary cylinder 105 can each have flow paths connected to the main cylinder side. In particular, a flow path 112 can be connected to the third hydraulic chamber 106 of the auxiliary cylinder 105, and the fourth hydraulic chamber 107, adjacent to the side of the pedal 101, can have a "y"-type flow path structure with two inlet ports and one outlet port on the side of the auxiliary cylinder 105. Accordingly, the fourth hydraulic chamber 107 can have a first flow path 115 near the side of the first auxiliary piston 108 and a second flow path 116 near the pedal 101, and be connected to the flow path 115.

[0035] The two inlet ports of the "y"-type flow path can be arranged forwards and backwards along the longitudinal direction of the auxiliary cylinder 105. The two inlet ports can be spaced apart from each other along the direction of movement of the auxiliary piston. The two inlet ports can be configured to transmit hydraulic pressure through the other of the flow paths even if one of the flow paths is closed when the auxiliary piston moves. In other words, hydraulic pressure can be transmitted through the flow path that is open while the other of the two remains closed.

[0036] The auxiliary cylinder 105 can be divided into two hydraulic chambers 106 and 107 by the first auxiliary piston 108. Specifically, the auxiliary cylinder 105 can have an inlet-side structure with a stepped section A, and the second auxiliary piston 109 can also have a corresponding structure. Accordingly, the section where the second auxiliary piston 109 is connected to the pedal side has a relatively small outer diameter, and the section extending towards the side of the fourth hydraulic chamber 107 has a relatively large outer diameter. In the pre-brake state, the second auxiliary piston 109 can be positioned so that it adjoins the stepped section A of the auxiliary cylinder 105. In this description, the piston with the stepped section is referred to as the stepped piston.The stepped piston can prevent the second auxiliary piston 109 from being pushed towards the pedal 101, thus preventing the rider from experiencing discomfort during the pressure equalization process. In other words, as in the... Fig. 2A and Fig. As shown in Figure 2B, even if pressure equalization is performed, the auxiliary piston cannot move through the stepped section of the auxiliary cylinder 105 to the side of the pedal 101, thus preventing the pedal 101 from moving towards the driver's foot. Therefore, even if pressure equalization is performed, no unnecessary force can be transmitted to the driver via the pedal 101.

[0037] The exemplary embodiment of the present invention illustrates, by way of example, the second auxiliary piston 109 of the stepped type, but the present invention is not limited to such a stepped piston, and it is understood that any structure which can prevent the pedal from being pressed in a pressure equalization process can be used without restriction. On the other hand, the first auxiliary piston 108 can be installed in the middle of the auxiliary cylinder 105 to separate two hydraulic chambers in the middle of the auxiliary cylinder 105, and can be configured to physically separate the third hydraulic chamber 106 from the fourth hydraulic chamber 107.

[0038] Furthermore, the first auxiliary piston 108 within the auxiliary cylinder 105 can be moved based on the pressure difference provided by both actuators, i.e., the pressure difference between the third hydraulic chamber 106 and the fourth hydraulic chamber 107. The piston 108 can perform the pressure equalization function to balance both pressures by eliminating the pressure difference on both sides while operating in conjunction with the flow paths 112, 115, and 116, which are connected to the first hydraulic chamber 131 and the second hydraulic chamber 132.

[0039] For example, if the vehicle is suddenly stopped by pressing the brake pedal, pressure is generated between the left and right brakes during the initial braking action, and thus temporary pre-tensioning of the brakes can occur, which impairs the vehicle's straight-line stability. According to the present invention, the pressure equalization function on the auxiliary cylinder 105 can fundamentally prevent the occurrence of pre-tensioning of the brakes at this point.

[0040] This process of pressure equalization is found in the Fig. 2A and Fig. 2B shown. In particular, it shows Fig. 2A selectively activates the auxiliary cylinder 105 connected to pedal 101 and the left and right hydraulic pressure lines connected to auxiliary cylinder 105, and shows that pressure equalization is carried out when the pressure at the left wheel is high. In other words, in Fig. 2A, because the pressure in the first hydraulic chamber 131 at the left wheel is higher than the pressure in the second hydraulic chamber 132 at the right wheel, the first auxiliary piston 108 moves to the right in response to this pressure difference, and thus the fluid in the right fourth hydraulic chamber 107 can be pressurized. As the first auxiliary piston 108 moves to the right while a force is applied to the right side, the left and right pressure difference can be eliminated, and pressure equalization between the left and right sides can be achieved.

[0041] At this point, the flow path 115 can be closed by the first auxiliary piston 108, and the braking force from the pressure equalization can be transferred to the second hydraulic chamber 132 through the open flow path 116. Therefore, the application of the "y"-type flow path to the fourth hydraulic chamber 107 in this exemplary embodiment, as shown, for example, in Fig. As shown in Figure 2A, the pressure equalization function of the auxiliary cylinder 105 is prevented from being lost due to the fact that the specific flow path through the first auxiliary piston 108 is closed. The third valve 117 and the fourth valve 118 on the reservoir side should be in the closed state, and the first valve 119 and the second valve 120 should be in the open state. ... Fig. As shown in Figure 3G, if both actuators fail and braking is performed by pedal force, the front flow path 116 of the auxiliary cylinder can be closed. The hydraulic pressure can then be transferred to the wheel side through the remaining flow path 115.

[0042] Furthermore, it shows Fig. 2B the pressure equalization, which is carried out by the auxiliary cylinder 105, when the pressure in the second hydraulic chamber 132 at the right wheel is higher than the pressure in the first hydraulic chamber 131 at the left wheel. Since the pressure is higher on the right side, the first auxiliary piston 108 can be moved to the left, and a braking force can be transmitted to the first hydraulic chamber 131 by pressure equalization through the flow path 112.

[0043] Fig. Figure 2C shows the emergency braking state activated by the driver's pedal force or by actuation in the event of an electrical failure. In this emergency braking state, all first through fourth valves must be open. Therefore, if all first through fourth valves normally use open valves, all valves can remain open even in the event of an electrical failure. With all valves open, the first auxiliary piston 108 and the second auxiliary piston 109 can move rearward under pedal force, thus transmitting the braking force to the wheel brakes 136 and 137. As shown in Fig. As shown in Figure 2C, the second auxiliary piston 109 can close the flow path 116, but since another flow path 115 to the fourth hydraulic chamber 107 is open, the pedal force can be sufficiently transmitted to the side of the second hydraulic chamber 132.

[0044] Furthermore, the flow path 112, which is connected to the third hydraulic chamber 106, can be located at the rear end of the auxiliary cylinder 105, i.e., at a distance from or separated from the pedal 101. Thus, the third hydraulic chamber 106 can be connected to the side of the first hydraulic chamber 131 without interfering with the movement of the first auxiliary piston. The internal structures of the flow paths 112, 115, and 116 and of the auxiliary cylinder 105 contribute significantly to achieving the pressure equalization and support brake functions, while substantially reducing the size of the auxiliary cylinder 105.

[0045] Fig. Sections 3A to 3G show examples in which the brake module for the front wheels operates according to different vehicle conditions. First, it shows Fig. 3A an initial state of the braking system for the vehicle before braking, and Fig. Figure 3B shows the operation of the vehicle's braking system during normal braking. In the initial state before braking, the first valve 119, the second valve 120, the third valve 117, and the fourth valve 118 are all open. When braking is performed, the control device 135 can be configured to close all of the first valve 119, the second valve 120, the third valve 117, and the fourth valve 118 and to operate the first motor 129 and the second motor 130 based on the brake input detected by the pedal sensor 104, in order to generate a braking force for each wheel.

[0046] Furthermore, it shows Fig. 3C, the pressure equalization that takes place in the initial stage of rapid braking. In the early phase of rapid braking, the movements of the motors are not precisely coordinated. As in Fig. As shown in 3C, the motor does not run smoothly. For example, in Fig. As shown in Figure 3C, the first motor 129 on the left can be in a state where a brake pressure is generated that is greater than the brake pressure from the second motor 130 during rapid braking. Pressure equalization can be carried out while the first auxiliary piston 108 moves to the right.

[0047] In particular, since the first hydraulic chamber 131 and the second hydraulic chamber 132 must be connected to the third hydraulic chamber 106 and the fourth hydraulic chamber 107 on the side of the auxiliary cylinder 105 for pressure equalization, the first valve 119 and the second valve 120 can be opened. Conversely, if the second motor 130 generates a brake pressure greater than the brake pressure from the first motor 129, as in Fig. As shown in Figure 2B, left and right braking forces can be generated equally by the pressure equalization process in the auxiliary cylinder 105.

[0048] In an exemplary embodiment of the present invention, the control unit 135 can be configured to determine whether rapid braking is occurring, and if the brake input detected by the pedal sensor exceeds a predetermined reference value, the control unit 135 can be configured to determine that the vehicle is in a rapid braking situation. The brake input can be a parameter such as pedal acceleration or pedal travel, etc.

[0049] Furthermore, it shows Fig. 3D a state in which pre-tensioned braking is achieved based on ABS or ESC operation. When ABS or ESC control is achieved, the actuator can be intentionally actuated unevenly to generate pre-tensioned braking. Therefore, in this ABS or ESC control state, the system must be actuated to prevent activation of the pressure equalization function of the auxiliary cylinder 105, and thus the first valve 119 and the second valve 120 can be closed. Accordingly, when the first valve 119 and the second valve 120 are closed, the first hydraulic chamber 131 and the second hydraulic chamber 132 can be completely separated from each other, and thus, as in Fig. As shown in 3D, significant braking pressure is exerted on the right wheel.

[0050] Fig. Figure 3E illustrates what happens when the actuator is broken or malfunctions, and shows a case where a fault occurs in the first motor 129. In the event of a failure of the first motor 129, it may be difficult to apply braking force to the left wheel using the normal braking mode. Therefore, the brake pressure generated in the second hydraulic chamber 132 can be transferred to the side of the first hydraulic chamber 131 by connecting the first hydraulic chamber 131 and the second hydraulic chamber 132. Since the brake pressure generated by one motor is distributed to the left and right, a loss of braking force occurs, but braking stability can be improved because braking of all four wheels is possible. Conversely, if only the second motor 130 fails, brake control can be performed by the first motor 129. Even if a fault occurs in one of the motors, braking can still be performed by another normal motor.

[0051] Additionally shows Fig. 3F describes the case where brake control is performed when a line break occurs on the left side. If the valve on the side where the line break occurred is opened, all the oil in the hydraulic pressure line can be consumed. At this point, therefore, the first valve 119 and the second valve 120 can be closed to minimize oil consumption by completely isolating the section where the line break occurred, and braking force is generated only by the normally operated actuator. On the other hand, it shows Fig. 3G is the emergency braking situation using the driver's pedal force due to a failure of the electrical system.

[0052] As in Fig. As shown in Figure 3G, in the event of a failure of an electrical system, both the first motor 129 and the second motor 130 are taken out of service. In the exemplary embodiment of the present invention, emergency braking can be performed using the driver's pedal force, even if an electrical system fails. During emergency operation, the first auxiliary piston 108 and the second auxiliary piston 109 within the auxiliary cylinder 105 can be actuated to apply a braking force to each wheel. The first valve 119, the second valve 120, the third valve 117, and the fourth valve 118 can be open, and the upper valves can be configured to normally open valves.

[0053] Fig. Figure 4 shows a braking device for a vehicle according to a further exemplary embodiment of the present invention. Fig. 4 is the same as the entire design of the Fig. 3A to 3G, with the exception of the flow structure connected to the first hydraulic chamber, the second hydraulic chamber, and the added valves. In other words, as in Fig. As shown in Figure 4, the flow paths 121 and 122 can be directly connected to the wheel brake side at the rear ends of the first valve and the second valve, and a fifth valve 141 and a sixth valve 142 can further be provided between the flow paths 121 and 122 and the first hydraulic chamber 131 and the second hydraulic chamber 132.

[0054] The added valve can be configured to optionally connect hydraulic pressure lines between the actuator and the wheel brakes. The number of valves can be increased as needed. Unlike Fig. 4. A number of wheels can be configured to be braked by hydraulic pressure through each actuator by incorporating an increased number of such valves. The fifth valve 141 and the sixth valve 142 can be normally closed. During normal braking, the valve can be opened, and thus a braking force can be exerted on the wheel brakes by the actuator. If the actuator fails or the electrical system fails, the valve can be automatically shut off, and operation with the valve closed is the same, except that the fluid does not flow through the first hydraulic chamber 131 and the second hydraulic chamber 132.

[0055] In this respect, in the exemplary embodiment described in Fig. As shown in Figure 1, a braking loss is generated to compensate for the displacement of the piston that was already actuated before the actuator failure in the emergency braking situation; however, according to the in Fig. The exemplary embodiment shown in Figure 4 offers the advantage of preventing the occurrence of a loss of braking power by closing the fifth valve 141 and the sixth valve 142.

Claims

[1] Braking system for a vehicle comprising: a pedal (101) to which a brake input is applied; an actuator part configured to generate a brake hydraulic pressure in response to the brake input applied to the pedal (101), and comprising a first actuator with a first hydraulic chamber (131) and a second actuator with a second hydraulic chamber (132); Wheel brakes (136, 137) connected to the first actuator and the second actuator; and an auxiliary cylinder (105) with two auxiliary pistons (108, 109) for forming a third hydraulic chamber (106) and a fourth hydraulic chamber (107), which are two hydraulic chambers that are continuously arranged in a housing; wherein the auxiliary cylinder (105) has a first centrally arranged auxiliary piston and a second auxiliary piston connected to the pedal (101), and wherein the first hydraulic chamber (131) is connected to the third hydraulic chamber (106) by a flow path (112, 121) in which a first valve (119) is installed, the second hydraulic chamber (132) is connected to the fourth hydraulic chamber (107) by a flow path (122, 115) in which a second valve (120) is installed, and pressure equalization is performed by the auxiliary cylinder when a difference occurs between the hydraulic brake pressures generated by the first actuator and the second actuator, wherein the fourth hydraulic chamber (107) is connected to a first flow path (115) adjacent to the first auxiliary piston (108) and to a second flow path (116), and wherein the first flow path (115) and the second flow path (116) are connected to the second valve (120), wherein the first auxiliary piston (108) separates the third hydraulic chamber (106) and the fourth hydraulic chamber (107), and wherein, when the flow path through the first auxiliary piston (108) is closed by the pressure difference between the third hydraulic chamber (106) and the fourth hydraulic chamber (107), the braking force is transmitted through the second flow path (116) to the second hydraulic chamber (132). [2] Braking system for the vehicle according to claim 1, wherein the first auxiliary piston (108) divides the third hydraulic chamber (106) and the fourth hydraulic chamber (107) and adjusts the pressures of the divided chambers uniformly as they move in a low-pressure direction when pressure equalization is carried out. [3] Brake system for the vehicle according to claim 1 or 2, wherein the first valve (119) and the second valve (120) are normally open valves. [4] Brake system for the vehicle according to one of the previous claims, wherein the fourth hydraulic chamber (107) is a hydraulic chamber subdivided by the first auxiliary piston (108) and the second auxiliary piston (109) and a y-shaped flow path is connected to the fourth hydraulic chamber (107). [5] Braking system for the vehicle according to claim 4, wherein the y-shaped flow path is formed along the longitudinal direction of the auxiliary cylinder (105) and has two ports connected to the fourth hydraulic chamber (107). [6] Braking system for the vehicle according to any of the previous claims, further comprising: a reservoir (133) which is connected to the third hydraulic chamber (106) and the fourth hydraulic chamber (107), respectively. [7] Braking system for the vehicle according to claim 6, further comprising: a third valve (117) attached to the flow path connecting the reservoir (133) and the third hydraulic chamber (106), and a fourth valve (118) which is attached to the flow path which connects the reservoir (133) and the fourth hydraulic chamber (107). [8] Brake system for the vehicle according to claim 7, wherein the third valve (117) and the fourth valve (118) are normally open valves. [9] Braking system for the vehicle according to any of the previous claims, wherein the first actuator comprises a first motor (129), a first main piston (127) which is moved back and forth by the first motor (129), and a first master cylinder (125) which receives the first main piston (127), and the second actuator comprises a second motor (130), a second main piston (128) which is moved back and forth by the second motor (130), and a second master cylinder (126) which receives the second main piston (127). [10] Brake system for the vehicle according to one of the previous claims, wherein the second auxiliary piston (108) is a stepped piston and in an initial state adjoins a stepped section (A) formed in the auxiliary cylinder (105). [11] Brake system for the vehicle according to one of the previous claims, wherein a pedal simulator (103) is installed between the second auxiliary piston (109) and the pedal (101). [12] Brake system for the vehicle according to one of the previous claims, wherein the auxiliary cylinder (105) further comprises: a return spring (110, 111) for resetting the positions of the first auxiliary piston (108) and the second auxiliary piston (109) to a predetermined position. [13] Braking system for the vehicle according to any of the previous claims, further comprising: a pedal sensor (104) designed to detect input from the pedal (101); and a controller (135) designed to perform brake control based on an output from the pedal sensor (104); wherein the control unit (135) is designed to actuate the actuators and the valves. [14] Braking system for the vehicle according to claim 13, wherein the control (135) is configured to close the first valve (119), the second valve (120), the third valve (117) and the fourth valve (118) in a normal braking situation and to operate the first actuator and the second actuator based on the brake input detected by the pedal sensor (104) to generate a braking force at each wheel. [15] Braking system for the vehicle according to claim 13 or 14, wherein the control (135) is configured to detect a rapid braking situation when the brake input detected by the pedal sensor (104) exceeds the predetermined reference value, and is configured to open the first valve (119) and the second valve (120) to perform pressure equalization in a state of closing the third valve (117) and the fourth valve (118). [16] Braking system for the vehicle according to any one of claims 13 to 15, wherein the control (135) is configured to completely close the first valve (119), the second valve (120), the third valve (117) and the fourth valve (118) to control each wheel independently when an anti-lock braking system (ABS) or electronic stability control (ESC) is performed. [17] Braking system for the vehicle according to one of claims 13 to 16, wherein in the event of a failure of the first actuator or the second actuator the control (135) is configured to open the first valve (119) and the second valve (120) in a state of closing of the third valve (117) and the fourth valve (118) in order to carry out braking by an actuator that does not produce a fault. [18] Braking system for the vehicle according to any one of claims 13 to 17, wherein the control (135) is designed to completely close the first valve (119), the second valve (120), the third valve (117) and the fourth valve (118) in order to control each wheel independently when an oil leak occurs in the hydraulic pressure lines. [19] Braking system for the vehicle according to any one of claims 13 to 18, wherein the first valve (119), the second valve (120), the third valve (117) and the fourth valve (118) are all configured to be normally open valves; and in the event of an electrical failure of the vehicle's braking system, the first valve (119), the second valve (120), the third valve (117) and the fourth valve (118) are all open to allow the braking force to be supplied to each wheel based on a pedal force. [20] Braking system for the vehicle according to any of the preceding claims, wherein the flow path in which the first valve (119) is installed and the flow path in which the second valve (120) is installed are directly connected to the wheel brakes; and a fifth valve (141) is installed between one of the wheel brakes and the first actuator, and a sixth valve (142) is installed between another wheel brake and the second actuator.

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