Braking device for a vehicle and braking method therefor

Abstract

Braking device (1000) for a vehicle having a first wheel brake (w1), a second wheel brake (w2), a third wheel brake (w3) and a fourth wheel brake (w4) for vehicle braking, the braking device (1000) comprising: a first brake controller (300) configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation; a first brake unit (100) comprising a reservoir, a backup brake cylinder (110), a master brake cylinder (120), and a pressure reducing valve (194) disposed between the reservoir and the backup brake cylinder (110), and configured to respond to the first valve opening / closing signal to control a valve between open and closed states and to supply a hydraulic braking force corresponding to the first hydraulic braking signal to the first to fourth wheel brakes (w1,w2,w3,w4); a second brake controller (400) configured to respond to an abnormal operation occurring in the first brake unit (100) to generate a second hydraulic brake signal and a second valve opening / closing signal instead of the first brake controller (300) generating the first hydraulic brake signal and the first valve opening / closing signal; and a second brake unit (200) configured to respond to the second valve opening / closing signal to control a valve between an open and closed state and to supply a hydraulic braking force corresponding to the second hydraulic braking signal to the third wheel brake (w3) and the fourth wheel brake (w4), wherein the second brake controller (400) is configured to respond to an abnormal operation occurring in the first brake unit (100) to take over control of opening and closing the pressure reducing valve (194) from the first brake controller (300) and to relieve a hydraulic pressure supplied to the first wheel brake (w1) and the second wheel brake (w2) when the second brake unit (200) is driven.

Description

TECHNICAL FIELD

[0001] The present disclosure relates, in some embodiments, to a braking device for a vehicle and a braking method therefor. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] With the ongoing development of autonomous vehicles, there is an increased need for driving safety. Vehicles are equipped with a first brake unit and a second brake unit. The first brake unit operates alone to normally deliver braking force to the respective wheel brakes until an abnormality occurs, at which point the second brake unit is triggered to ensure the stability of the vehicle's propulsion and braking.

[0004] Adding the second brake unit has a detrimental impact on cost control. To save costs, the second brake unit is downsized so that it hydraulically brakes only two of the vehicle's wheels. An electronic parking brake (EPB) device is used to brake the remaining two wheels, which the second brake unit cannot control. However, when the vehicle is in autonomous driving mode and a situation requires the second brake unit to initiate sudden braking, the remaining two wheels, which are outside the control of the second brake unit, are supplied with hydraulic pressure generated from a backup brake cylinder by the driver depressing the brake pedal. If the hydraulic pressure is not relieved, the wheels may lock, especially on low-friction road surfaces, which could lead to an accident.DE 11 2019 001 312 T5 discloses a braking device for a vehicle, comprising a first wheel brake, a second wheel brake, a third wheel brake, and a fourth wheel brake for vehicle braking, including a first brake controller, a first brake unit, a second brake controller, and a second brake unit. The first brake controller is configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation. The first brake unit includes a reservoir, a master brake cylinder, and a pressure reducing valve, and is configured to respond to the first valve opening / closing signal to control a valve between an open and closed state and to supply a hydraulic braking force corresponding to the first hydraulic brake signal to the first to fourth wheel brakes.The second brake controller is configured to respond to an abnormal operation occurring in the first brake unit to generate a second hydraulic brake signal and a second valve opening / closing signal instead of the first brake controller generating the first hydraulic brake signal and the first valve opening / closing signal. The second brake unit is configured to respond to the second valve opening / closing signal to control a valve between an open and closed state and to supply a hydraulic braking force corresponding to the second hydraulic brake signal to the third wheel brake and the fourth wheel brake. Here, the second brake controller is configured to respond to an abnormal operation occurring in the first brake unit. It is an object of the present invention to improve the above-described braking devices while avoiding the aforementioned disadvantages. OVERVIEW

[0005] According to at least one embodiment, the present invention provides a braking device for a vehicle to achieve the object of the invention, comprising a first wheel brake, a second wheel brake, a third wheel brake, and a fourth wheel brake for braking the vehicle, including a first brake controller, a first brake unit, a second brake controller, and a second brake unit. The first brake controller is configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation.The first brake unit includes a reservoir, a backup brake cylinder, a master cylinder, and a pressure reducing valve disposed between the reservoir and the backup brake cylinder. The first brake unit is configured to respond to the first valve opening / closing signal to control a valve between open and closed states and supply hydraulic braking force corresponding to the first hydraulic braking signal to the first to fourth wheel brakes. The second brake controller is configured to respond to an abnormal operation occurring in the first brake unit to generate a second hydraulic braking signal and a second valve opening / closing signal instead of the first brake controller generating the first hydraulic braking signal and the first valve opening / closing signal.The second brake unit is configured to respond to the second valve opening / closing signal to control a valve between an open and closed state and to supply hydraulic braking force corresponding to the second hydraulic braking signal to the third wheel brake and the fourth wheel brake. Here, the second brake controller is configured to respond to an abnormal operation occurring in the first brake unit to take over control of opening and closing the pressure reducing valve from the first brake controller and to relieve the hydraulic pressure supplied to the first wheel brake and the second wheel brake when the second brake unit is driven.

[0006] According to another embodiment, the present invention provides a braking device for a vehicle to achieve the object of the invention, comprising a first wheel brake, a second wheel brake, a third wheel brake, and a fourth wheel brake for braking the vehicle, including a first brake controller, a first brake unit, a second brake controller, and a second brake unit. The first brake controller is configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation.The first brake unit includes first to fourth inlet valves and a first outlet valve, a second outlet valve, a third outlet valve, and a fourth outlet valve arranged to control hydraulic pressure supplied to the first to fourth wheel brakes, and is configured to respond to the first valve opening / closing signal to control a valve between open and closed states and to supply hydraulic braking force corresponding to the first hydraulic braking signal to the first to fourth wheel brakes. The second brake controller is configured to respond to an abnormal operation occurring in the first brake unit to generate a second hydraulic braking signal and a second valve opening / closing signal instead of the first brake controller generating the first hydraulic braking signal and the first valve opening / closing signal.The second brake unit is configured to respond to the second valve opening / closing signal to control a valve between an open and closed state and to supply hydraulic braking force corresponding to the second hydraulic braking signal to the third wheel brake and the fourth wheel brake. Here, the second brake controller is configured to respond to an abnormal operation occurring in the first brake unit, to take over control of the opening and closing of the first exhaust valve and the second exhaust valve from the first brake controller, and to relieve hydraulic pressure supplied to the first wheel brake and the second wheel brake when the second brake unit is driven.

[0007] According to yet another embodiment, to achieve the object of the invention, the present invention provides a method for controlling a braking device for a vehicle having a first wheel brake, a second wheel brake, a third wheel brake, and a fourth wheel brake for braking the vehicle, the method comprising: determining whether a first brake unit is operating normally when it is determined that a braking situation has occurred during driving of the vehicle, and braking the vehicle when it is determined that the first brake unit is not operating normally by supplying hydraulic pressure to the third wheel brake and the fourth wheel brake by actuating a second brake unit, and preventing wheel locks of a first wheel and a second wheel provided on the vehicle by opening a pressure reducing valve when it is determined that a driver has intervened in the braking situation. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a block diagram of a vehicle braking device with a normally operating first braking unit according to at least one embodiment of the present disclosure. Fig. 2 shows a block diagram of the vehicle braking device when the first braking unit is operating abnormally according to at least one embodiment of the present disclosure. Fig. 3 shows a block diagram of a vehicle braking device according to at least one embodiment of the present disclosure. Fig. 4 to 8 are block diagrams illustrating flows of hydraulic pressure in a vehicle braking device according to at least one embodiment of the present disclosure. Fig. 9 shows a flowchart of a braking method according to at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0008] The present disclosure aims to prevent wheel locking by providing a first brake unit having a pressure reducing valve among other valves so that the pressure reducing valve is controlled by a second brake controller.

[0009] The present disclosure further aims to prevent wheel locking by enabling the second brake controller to control a first exhaust valve and a second exhaust valve among valves arranged in the first brake unit.

[0010] Some embodiments of the present disclosure are described below with reference to the accompanying drawings. In the following description, like reference numerals preferably refer to like elements even though the elements are shown in different drawings. Furthermore, for the sake of clarity and conciseness, the following description of some embodiments omits a detailed description of known functions and configurations incorporated herein.

[0011] Furthermore, alphanumeric codes such as first, second, i), ii), a), b), etc., are used in component numbering solely to distinguish one component from another, not to imply or indicate the substances, order, or sequence of the components. In this specification, when parts "include" or "comprise" a component, this means that they include and do not exclude other components, unless otherwise described.

[0012] In this specification, the terms "left" and "right" are used solely to indicate a direction in which certain elements are shown in the drawings, and this disclosure is not limited to their illustrated orientations and positions.

[0013] Fig. 1 shows a block diagram of a vehicle braking device with a normally operating first braking unit according to at least one embodiment. Fig. 2 shows a block diagram of the vehicle braking device when the first braking unit is operating abnormally according to at least one embodiment. Fig. 3 shows a block diagram of a vehicle braking device according to at least one embodiment of the present disclosure.

[0014] As in the Fig. 1 to 3, a braking device 1000 for a vehicle includes all or some of the following: a first braking unit 100, a second braking unit 200, a first braking controller 300, a second braking controller 400, an electronic parking brake (EPB) operator 500, an EPB controller 600, a communication unit 700, and a plurality of wheel brakes w1, w2, w3, and w4.

[0015] A plurality of wheel brakes w1, w2, w3, w4 includes a first wheel brake w1 for braking a left rear wheel of the vehicle, a second wheel brake w2 for braking a right rear wheel, a third wheel brake w3 for braking a left front wheel, and a fourth wheel brake w4 for braking a right front wheel. Here, the first to fourth wheel brakes w1 to w4 are formally defined for convenience of description, and the respective positions of the wheel brakes are not limited to the positions defined above.

[0016] The first brake unit 100 is described in detail below.

[0017] The first brake unit 100 includes all or some of the following: a backup brake cylinder 110, a master brake cylinder 120, first to fourth inlet valves 181, 182, 183, 184 and first to fourth outlet valves 185, 186, 187, 188, a mixing valve 193, a pressure reducing valve 194 above the backup brake cylinder 110, first to third backup valves 195, 196, 197, and first and second main control valves 191, 192.

[0018] The backup brake cylinder 110 includes all or some of the following: a backup body 111, a first backup piston 112, a second backup piston 113, a backup stopper 114, a reaction force damper 115, a first elastic member 116, and a second elastic member 117.

[0019] The backup body 111 is formed into a structure having an internal cavity. The first backup piston 112 and the second backup piston 113 are arranged within the interior of the backup body 111 so as to be able to move linearly to the left and right. A first backup chamber 118 is defined by an interior space of the backup body 111 between the first backup piston 112 and the second backup piston 113. A second backup chamber 119 is defined by an interior space of the backup body 111 between the second backup piston 113 and the backup stopper 114.

[0020] The backup body 111 is configured to be open at its left and right ends. The left end of the first backup piston 112 is inserted into the open right end of the backup body 111. Then, the open right end of the backup body 111 is closed by the first backup piston 112. The right end of the first backup piston 112, to which a brake pedal 101 is connected, protrudes from the right end of the backup body 111. The brake pedal 101 may be provided with a stroke sensor 102 that detects the amount of pedal stroke of the brake pedal 101 when the driver depresses it. The first backup piston 112 is arranged to move linearly left and right while in close contact with the inner wall of the backup body 111.

[0021] The backup stopper 114 is positioned such that the right end of the backup stopper 114 is adjacent to the open left end of the backup body 111. Subsequently, the right end of the backup stopper 114 is inserted into the open left end of the backup body 111 to close the same open left end.

[0022] The second backup piston 113 is arranged inside the backup body 111 to move linearly left and right while being in close contact with the inner wall of the backup body 111. The second backup piston 113 is arranged to be spaced apart from the first backup piston 112 and the backup stopper 114.

[0023] The second backup piston 113 is formed in an empty structure. The second backup piston 113 is configured such that the right side facing the first backup piston 112 is blocked and the left side facing the backup stopper 114 is open.

[0024] The first elastic member 116 is arranged between the first backup piston 112 and the second backup piston 113. The first elastic member 116 may be formed from a spring. The first elastic member 116 has one end that elastically supports the first backup piston 112 and the other end that elastically supports the second backup piston 113.

[0025] The second elastic member 117 is arranged between the second backup piston 113 and the backup stopper 114. The second elastic member 117 may be formed from a spring. The second elastic member 117 has one end that elastically supports the second backup piston 113 and the other end that elastically supports the backup stopper 114.

[0026] The reaction force damper 115 is arranged in the second backup piston 113. The reaction force damper 115 has one end supported by the right end of the backup stopper 114 and the other end supported by the inner surface of the right end of the second backup piston 113. When the driver depresses the brake pedal 101, the reaction force damper 115 moves to the left within the second backup piston 113, and the reaction force damper 115 is compressed so that the driver can feel a reaction force. The reaction damper 115 can be formed of a rubber or a spring and can provide a feeling of a reaction force to a driver depressing the brake pedal 101 through the elastic resilience of the rubber or spring.

[0027] The brake master cylinder 120 includes all or some of the following: a main body 121, a main piston 122, an actuator 150, and a main stop 124.

[0028] The main body 121 is formed into a structure having an internal cavity. The main piston 112 is arranged so that it can be moved linearly to the right and left within the interior of the main body 121. The interior of the main body 121 is divided into two spaces by the main piston 122. A first main chamber 125 is defined by the interior of the main body 121 on the left side of the main piston 122. A second main chamber 126 is defined by the interior of the main body 121 on the right side of the main piston 122.

[0029] When the main piston 122 advances to the right, it expands the first main chamber 125 and constricts the second main chamber 126. Conversely, when the main piston 122 moves back to the left, it constricts the first main chamber 125 and expands the second main chamber 126.

[0030] The main body 121 is open at its left end and its right end. The right end of the main body 121 is completely open, and the left end of the main body 121 is partially open in the middle.

[0031] The actuator 150 includes a motor 152, an external thread 123, and an internal thread (not shown). The external thread 123 is arranged so that its right end is inserted into the open left end of the main body 121. The right end of the external thread 123 is connected to the main piston 122 in the main body 121. The external thread 123 may be integrally formed with the main piston 122. The external thread 123 is formed to have a diameter smaller than the diameter of the main piston 122. The internal thread (not shown) has a spiral formation on its inner peripheral surface. The external thread 123 has a spiral formation on its outer peripheral surface, which meshes with the spiral formation of the internal thread and is inserted into the internal thread.

[0032] The left end of the external thread 123 protrudes from the left end of the main body 121. The protruding left end is installed with a motor 152 for linearly moving the external thread 123 left and right. The external thread 123 is connected to the rotor shaft of the motor 152. The external thread 123 rotates with the rotor shaft of the motor 152, thereby moving linearly. In other words, the external thread 123 and the internal thread can convert the rotational movement of the motor 152 into linear movement, allowing the main piston 122 connected to the external thread 123 to move linearly left and right.

[0033] The left end of the main stopper 124 is inserted into the open right end of the main body 121. Accordingly, the open right end of the main body 121 is closed by the main stopper 124.

[0034] The main piston 122 is configured to move linearly left and right while being in close contact with the inner wall of the main body 121. Specifically, the main piston 122 has outer peripheral surfaces whose center is in close contact with the inner wall of the main body 121 and whose left and right ends are spaced apart from the inner wall of the main body 121. The main piston 122 has a hollow center. The external thread 123 is also configured to have a hollow center. The main stopper 124 is arranged to penetrate both the main piston 122 and the external thread 123.

[0035] The first main chamber 125 includes the main piston 122 and the external thread 123, but the external thread 123 is not located in the second main chamber 126. Accordingly, when the main piston 122 advances to the right, the effective cross-sectional area of the second main chamber 126 becomes larger than that of the first main chamber 125.

[0036] The brake master cylinder 120 generates hydraulic pressure by rotating the motor 152 and supplies the generated hydraulic pressure to a plurality of wheel brakes w1, w2, w3, w4. Specifically, when the driver depresses the brake pedal 101, the stroke sensor 102 detects the stroke of the brake pedal 101 and sends a detection signal to the first brake controller 300, which then calculates the pedal stroke of the brake pedal 101 based on the received detection signal. The first brake controller 300 can control the motor 152 based on the calculated pedal stroke, thereby controlling the hydraulic pressure generated by the brake master cylinder 120.

[0037] The following describes in detail the brake structure using the hydraulic pressure of the first brake unit 100 including the backup brake cylinder 110 and the master brake cylinder 120.

[0038] The first brake unit 100 has a first main flow path 165, one end of which is connected to the first main chamber 125. Specifically, one end of the first main flow path 165 is connected to the main body 121 to receive hydraulic pressure transmitted from the first main chamber 125.

[0039] The opposite end of the first main flow path 165 is installed with the first main control valve 191 to open and close the first main flow path 165. The first main control valve 191 can regulate the hydraulic pressure supplied from the backup brake cylinder 110 or the master cylinder 120. The first main control valve 191 is a solenoid valve capable of opening and closing the first main flow path 165 according to a control signal from the first brake controller 300. For example, the first main control valve 191 can be arranged in a flow path that supplies hydraulic pressure to the first main chamber 125 of the first and second wheel brakes w1 and w2. The first main control valve 191 is further installed with a first main control check valve 191a.The first main control check valve 191a is opened when the hydraulic pressure in the first main chamber 125 is higher than a certain pressure, and serves as a bypass to supply the hydraulic pressure in the first main chamber 125 to the first and second wheel brakes w1 and w2 while the first main control valve 191 is closed.

[0040] The first brake unit 100 has a second main flow path 166, one end of which is connected to the second main chamber 126. Specifically, one end of the second main flow path 166 is connected to the main body 121 to receive hydraulic pressure transmitted from the second main chamber 126.

[0041] The opposite end of the second main flow path 166 is connected to the second main control valve 192 for opening and closing the second main flow path 166. The second main flow valve 192 is a solenoid valve capable of opening and closing the second main flow path 166 according to a control signal from the first brake controller 300. For example, the second main control valve 192 may be arranged in a flow path that supplies hydraulic pressure to the second main chamber 126 of the third and fourth wheel brakes w3 and w4. The second main control valve 192 is further installed with a second main control check valve 192a.The second main control check valve 192a is opened when the hydraulic pressure in the second main chamber 126 is higher than a certain pressure, and serves as a bypass to supply the hydraulic pressure in the second main chamber 126 to the third and fourth wheel brakes w3 and w4 while the second main control valve 192 is closed.

[0042] The first brake unit 100 includes a first brake flow path 161 having one end at which the first main control check valve 191 is disposed. The first main control check valve 191 is disposed between the first main flow path 165 and the first brake flow path 161. A first inlet valve 181 capable of regulating a hydraulic pressure supplied to the first wheel brake w1 and a second inlet valve 182 capable of regulating a hydraulic pressure supplied to the second wheel brake w2 are disposed in the first brake flow path 161. The first inlet valve 181 and the second inlet valve 182 are solenoid valves capable of opening and closing the first brake flow path 161 in accordance with a control signal from the first brake controller 300. The first inlet valve 181 and the second inlet valve 182 may include a first inlet check valve 181a and a second inlet check valve 182a, respectively.The first inlet check valve 181a and the second inlet check valve 182a are configured to prevent the backflow of hydraulic oil in the opposite direction away from the first wheel brake w1 and the second wheel brake w2.

[0043] The first wheel brake w1 and the second wheel brake w2 are arranged at the other end of the first brake flow path 161. A first outlet valve 185 and a second outlet valve 186 are arranged between the first brake flow path 161 and a first return flow path 162, which is also included. The first outlet valve 185 and the second outlet valve 186 are solenoid valves arranged to open and close, controlled by a control signal from the first brake controller 300, in order to recover the hydraulic oil supplied to the first wheel brake w1 and the second wheel brake w2. The first outlet valve 185 and the second outlet valve 186 can be connected in parallel not only with the first brake controller 300, but also with the second brake controller 400 in order to also be controlled by the second brake controller 400.

[0044] For example, when the driver depresses the brake pedal 101 or a braking situation occurs during autonomous driving of a vehicle, the first brake controller 300 may control the first inlet valve 181 and the second inlet valve 182 to open to supply braking force to the first wheel brake w1 and the second wheel brake w2. Conversely, after the driver completes the operation of the brake pedal 101 or the braking situation is completed during autonomous driving of the vehicle, the first brake controller 300 controls the closing of the first inlet valve 181 and the second inlet valve 182 to prevent hydraulic pressure from activating the first wheel brake w1 and the second wheel brake w2, and the opening of the first outlet valve 185 and the second outlet valve 186 to recover the hydraulic oil.

[0045] The first return flow path 162 is a flow path for transferring the recovered hydraulic oil to a reservoir contained in the first brake unit 100. Here, the reservoir is an oil tank for storing hydraulic oil.

[0046] The first brake unit 100 further comprises a second brake flow path 163, a second return flow path 164, a third inlet valve 183, a fourth inlet valve 184, a third inlet check valve 183a, a fourth inlet check valve 184a, a third outlet valve 187, a fourth outlet valve 188, the third wheel brake w3 and the fourth wheel brake w4, whose respective functions and relationships are identical to those of the above-described first and second wheel brakes w1, w2 and the associated hydraulic components, so that a repeated description thereof is omitted.

[0047] In contrast to the first brake flow path 161, the second brake flow path 163 supplies the third wheel brake w3 and the fourth wheel brake w4 with hydraulic pressure not directly, but indirectly via the second brake unit 200. A detailed description of the second brake unit 200 is presented below.

[0048] The first brake unit 100 further includes a third return flow path 168, one end of which is connected to the reservoir. The other end of the third return flow path 168 is branched into two parts, one of which is connected to the first return flow path 162 and the other to the second return flow path 164. The first backup valve 195 is installed between the third return flow path 168 and the second main flow path 166 to open and close the flow path therebetween. The first backup valve 195 is a solenoid valve.

[0049] A mixing flow path 167 is provided, one end of which is connected to the first brake flow path 161 and the other end of which is connected to the second brake flow path 163. The mixing flow path 167 is installed with a mixing valve 193 that can open and close the mixing flow path 167 following a control signal from the first brake controller 300. The mixing valve 193 is a solenoid valve.

[0050] A supply flow path 173 is provided, one end of which is connected to the reservoir and the other end of which is installed with a supply check valve 105. Here, the supply check valve 105 prevents backflow of the hydraulic oil supplied to the first main flow path 165 from the reservoir.

[0051] A first backup flow path 171 is provided, one end of which is connected to the reservoir and the other end of which is connected to the first backup chamber 118. The first backup flow path 171 is thus connected to the backup body 111 to communicate with the first backup chamber 118, allowing hydraulic oil to pass between the reservoir and the first backup chamber 118.

[0052] A second backup flow path 172 is provided, one end of which is connected to the reservoir and the other end of which is connected to the second backup chamber 119. The second backup flow path 172 is thus connected to the backup body 111 to communicate with the second backup chamber 119, allowing hydraulic oil to pass between the reservoir and the second backup chamber 119.

[0053] A third backup flow path 175 is provided, one end of which is connected to the first backup chamber 118. Accordingly, the third backup flow path 175 is connected to the backup body 111 to communicate with the first backup chamber 118, allowing hydraulic oil supplied from the first backup chamber 118 to pass therethrough. The second backup valve 196 for opening and closing the third backup flow path 175 is arranged at the other end of the third backup flow path 175. The third backup flow path 175, between the backup body 111 and the third backup valve 197, is installed with a third pressure sensor 107.

[0054] A fourth backup flow path 176 is provided, one end of which is connected to the second backup chamber 119. The fourth backup flow path 176 is thus connected to the backup body 111 to communicate with the second backup chamber 119, allowing the hydraulic oil supplied from the second backup chamber 119 to pass therethrough. The other end of the fourth backup flow path 176 is connected to the third backup valve 197 to open and close the fourth backup flow path 176. The first to third backup valves 195, 196, and 197 can regulate hydraulic pressure between the backup brake cylinder 110 and the master cylinder 120.

[0055] The pressure reducing valve 194, arranged between the second backup flow path 172 and the fourth backup flow path 176, controls the opening and closing of the intermediate flow path. The pressure reducing valve 194 and the first to third backup valves 195, 196, 177 are solenoid valves that control the opening and closing of the respective flow paths according to the control signals from the first brake controller 300. The pressure reducing valve 194 serves to prevent the amount of hydraulic pressure generated in the second backup chamber 119 from increasing beyond a predetermined level. To maintain the hydraulic pressure applied to the fourth backup flow path 176 at or below the predetermined level, the first brake controller 300 can control the opening and closing of the pressure reducing valve 194. Furthermore, the pressure reducing valve 194 can be controlled by the second brake controller 400.When the first brake unit 100 is operating normally, the opening and closing of the pressure reducing valve 194 is controlled by the first brake controller 300. On the other hand, when an abnormality occurs in the operation of the first brake unit 100, the second brake controller 400 assumes control of the opening and closing of the pressure reducing valve 194. In a parallel implementation in which the second brake controller 400 participates in controlling the pressure reducing valve 194, the second brake controller 400 is authorized to prevent wheel locks of the first and second wheel brakes w1 and w2. A control method for preventing wheel locks of the first and second wheel brakes w1 and w2 will be described below.

[0056] The second brake unit 200 is described in detail below.

[0057] The second brake unit 200 includes all or some of the following: a hydraulic motor 210, first and second hydraulic pumps 211 and 212, a pulsation damper 220, fifth and sixth inlet valves 283 and 284, fifth and sixth outlet valves 287 and 288, first and second traction control valves 291 and 292, and first and second high-pressure changeover valves 241 and 242.

[0058] The hydraulic motor 210 supplies driving force to the first and second hydraulic pumps 211 and 212. The first and second hydraulic pumps 211 and 212 discharge hydraulic oil through their outlets using the driving force provided by the hydraulic motor 210. The number of hydraulic pumps connected to the hydraulic motor 210 is not limited to two; one, three, or more hydraulic pumps may be provided.

[0059] The pulsation damper 220 is provided between a third brake flow path 261 and a fourth brake flow path 263, which are further provided in the second brake unit 200, to absorb the pressure surge of the hydraulic oil and thus reduce the pressure pulsation. The pulsation damper 220 is capable of expanding its internal space to absorb the pressure surge of the hydraulic oil.

[0060] The fifth inlet valve 283 controls the opening and closing of the third brake flow path 261, which transmits hydraulic pressure to the third wheel brake w3, and the sixth inlet valve 284 controls the opening and closing of the fourth brake flow path 263, which transmits hydraulic pressure to the fourth wheel brake w4. The fifth inlet valve 283 and the sixth inlet valve 284 are solenoid valves that are controllably opened and closed by the second brake controller 400.

[0061] The fifth inlet valve 283 and the sixth inlet valve 284 may include a fifth inlet check valve 283 and a sixth inlet check valve 284. The fifth inlet check valve 283a and the sixth inlet check valve 284a are configured to prevent the backflow of hydraulic oil in the opposite direction away from the third wheel brake w3 and the fourth wheel brake w4.

[0062] The fifth outlet valve 287 is connected to a fourth return flow path 262, which is further provided, and opens to direct the hydraulic pressure to the reservoir after the braking situation has ended. The sixth outlet valve 288 is connected to a fifth return flow path 264, which is further provided, and opens to direct the hydraulic pressure to the reservoir after the braking situation has ended.

[0063] The first traction control valve 291 and the second traction control valve 292 are each connected to one end of each second brake flow path 163 of the first brake unit 100 to regulate the hydraulic pressure supplied to the third brake flow path 261 and the fourth brake flow path 263. Therefore, the first traction control valve 291 and the second traction control valve 292 can regulate the hydraulic pressure supplied from the first brake unit 100 to the second brake unit 200.

[0064] When the first brake unit 100 is operating normally, the hydraulic motor 210 of the second brake unit 200 is not operating. Accordingly, the second brake controller 400 sends a control signal to open the first traction control valve 291 and the second traction control valve 292 to supply the hydraulic pressure transmitted from the first brake unit 100 to the third and fourth wheel brakes w3 and w4. When an abnormality occurs in the operation of the first brake unit 100, the second brake controller 400 sends a control signal to close the first traction control valve 291 and the second traction control valve 292 to regulate the hydraulic pressure transmitted from the brake unit 100. Accordingly, the third and fourth wheel brakes w3 and w4 are supplied with hydraulic pressure from the second brake unit 200.

[0065] The first traction control valve 291 is installed with a first traction control check valve 291a. The first traction control check valve 291a is open when the hydraulic pressure in the second brake flow path 163 is higher than a certain pressure to serve as a bypass, and the first traction control valve 291 is closed to allow the hydraulic pressure in the second brake flow path 163 to be supplied to the third and fourth wheel brakes w3 and w4. Similarly, a second traction control check valve 292a is installed on the second traction control valve 292.

[0066] The first high-pressure switching valve 241 is arranged between the third main flow path 260 and the third brake flow path 261. The second high-pressure switching valve 242 is arranged between the third main flow path 260 and the fourth brake flow path 263. The first high-pressure switching valve 241 and the second high-pressure switching valve 242 are solenoid valves that receive a control signal from the second brake controller 400 and regulate the hydraulic pressure supplied from the reservoir. The first high-pressure switching valve 241 and the second high-pressure switching valve 242 can thus regulate the hydraulic pressure supplied from the reservoir to the second brake unit 200. During normal operation of the first brake unit 100, the second brake controller 400 blocks the hydraulic pressure by sending a control signal to close the first high-pressure switching valve 241 and the second high-pressure switching valve 242.Conversely, when an abnormality occurs in the operation of the first brake unit 100, the second brake controller 400 sends a control signal to open the first high-pressure switching valve 241 and the second high-pressure switching valve 242 to allow hydraulic pressure to pass.

[0067] The remaining configuration, except for the first brake unit 100 and the second brake unit 200, is described in detail below.

[0068] The first brake controller 300 may be configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in a braking situation of the vehicle. Here, the first hydraulic brake signal is a signal sent from the first brake controller 300 to the first brake unit 100 and is a signal for the first brake unit 100 to drive the actuator 150 to generate hydraulic pressure. Here, the first valve opening / closing signal is a signal sent from the first brake controller 300 to the first brake unit 100 to control the opening and closing of various valves installed in the first brake unit. The first brake unit 100 may control the opening and closing of the valve by the first valve opening / closing signal and supply hydraulic braking force to the plurality of wheel brakes w1 to w4 according to the first hydraulic brake signal.

[0069] The first brake controller 300 can control the valves included in the first brake unit 100 and the actuator 150 of the master cylinder 120. Specifically, the first brake controller 300 can control the hydraulic flow in the flow path in the first brake unit 100 by sending a signal to control the opening and closing of the valves included in the first brake unit 100. Furthermore, the first brake controller 300 can diagnose whether the first brake unit 100 has a malfunction and can send a diagnosis result signal to the communication unit 700 to provide information about the diagnosis result to the second brake controller 400 and the EPB controller 600.

[0070] When an abnormality occurs in the operation of the first brake unit 100, the second brake unit 400 is operated instead of the first brake unit 300 to generate a second hydraulic brake signal and a second valve opening / closing signal. Here, the second hydraulic brake signal is a signal sent from the second brake controller 400 to the second brake unit 200 so that the second brake unit 200 can drive the hydraulic motor 210 to generate hydraulic pressure. Here, the second valve opening / closing signal is a signal sent from the second brake controller 400 to the second brake unit 200 and some valves arranged in the first brake unit 100, and controls the opening and closing of various valves in the second brake unit 200 and some valves in the first brake unit 100.The second brake unit 200 can control the opening and closing of the valves according to the second valve opening / closing signal and supply hydraulic pressure according to the second hydraulic brake signal to the third and fourth wheel brakes w3 and w4.

[0071] The second brake controller 400 can control the valves included in the second brake unit 200 and the hydraulic motor 210. Specifically, the second brake controller 400 can control the hydraulic flow in the flow path in the second brake unit 200 by sending a signal that controls the opening and closing of the valves included in the first brake unit 100. Furthermore, the second brake controller 400 can diagnose whether or not the second brake unit 200 has a malfunction and send a diagnosis result signal to the communication unit 700 to provide the diagnosis result information to the first brake controller 300 and the EPB controller 600.

[0072] The second brake controller 400 can control not only the second brake unit 200, but also the opening and closing of the pressure reducing valve 194 in the first brake unit 100.

[0073] The second brake controller 400 does not drive the hydraulic motor 210 of the second brake unit 200 when the first brake unit 100 is operating normally. The second brake controller 400 controls the second brake unit 200 and the pressure reducing valve 194 when it receives a signal from the communication unit 700 indicating that an abnormality has occurred in the operation of the first brake unit 100. A detailed control method is described below.

[0074] The EPB controller 600 and the EPB operator 500 are braking devices. After the vehicle is parked, the EPB controller 600 signals the EPB operator 500 to apply braking force to the first wheel and the second wheel to bring the vehicle to a stop. However, the use of the EPB controller 600 and the EPB operator 500 is not limited to the case of parking, and they can be used together with the second brake unit 200 when the first brake unit 100 is faulty. Here, the first wheel and the second wheel refer to the wheels installed with the first wheel brake w1 and the second wheel brake w2.

[0075] When a signal indicating that an abnormality has occurred in the operation of the first brake unit 100 is received from the communication unit 700, the EPB controller 600 sends a control signal to the EPB operator 500 to provide the braking force to the first and second edges.

[0076] The first brake controller 300, the second brake controller 400, and the EPB controller 600 may be arranged together in an integrated control device in a vehicle, a so-called electronic control unit (ECU), and the respective controllers may be physically isolated and located in a separate location in the vehicle.

[0077] The communication unit 700 is a medium that can send information between the first brake controller 300, the second brake controller 400, and the EPB controller 600. The communication unit 700 can send information not only to the first brake controller 300, the second brake controller 400, and the EPB controller 600, but also to other control units or sensing devices located in other vehicles. The communication unit 700 can be a control area network (CAN) communication.

[0078] Fig. 4 to 8 are block diagrams illustrating flows of hydraulic pressure in a vehicle braking device according to at least one embodiment of the present disclosure.

[0079] At least one embodiment of the present disclosure is described in detail below. To simplify the description of each embodiment, only one embodiment is presented for each situation, although the present disclosure is not limited to the illustrated embodiments.

[0080] The first main control valve 191 and the second main control valve 192 may be configured as a normally open type, which is normally open when no control signal is input from the first brake controller 300. The mixing valve 193 may be configured as a normally closed type, which is normally closed when no control signal is input from the first brake controller 300.

[0081] The pressure reducing valve 194 and the first backup valve 195 may be configured as a normally closed type, which is normally closed when no control signal is input from the first brake controller 300. Accordingly, the second backup valve 196 and the third backup valve 197 may be configured as a normally open type, which is normally open when no control signal is input from the first brake controller 300.

[0082] The following describes the flow of hydraulic pressure when the first brake unit 100 operates normally, as shown in Fig. 4. In particular, the Fig. 4 illustrates at least one embodiment of a method in which the first brake unit 100 is driven when the vehicle is traveling autonomously without driver intervention.

[0083] Hydraulic oil stored in the reservoir is supplied through the supply flow path 173 to the first main chamber 125 of the master cylinder 120. When a braking situation occurs, the first brake controller 300 controls the actuator 150 to supply hydraulic pressure to the plurality of wheel brakes w1, w2, w3, and w4. To this end, the first brake controller 300 controls the actuator 150 to cause the main chamber 125 to compress its internal hydraulic oil. The hydraulic pressure generated by the compression of the hydraulic oil in the first main chamber 125 passes through the first main flow path 165 and the first brake flow path 161 to be provided to the first wheel brake w1 and the second wheel brake w2.The first brake controller 300 causes the first main control valve 191, the first inlet valve 181 and the second inlet valve 182 to open so that the hydraulic oil supplied from the first main chamber 125 reaches the first and second wheel brakes w1 and w2.

[0084] In addition, the hydraulic pressure generated by the compression of the hydraulic oil in the first main chamber 125 is passed through the first main flow path 165, the first brake flow path 161, the mixed flow path 167, the second brake flow path 163, the third brake flow path 261 and the fourth brake flow path 263 before the hydraulic pressure of the third and fourth wheel brakes w3 and w4 is provided. In order for the hydraulic oil supplied from the first main chamber 125 to reach the third and fourth wheel brakes w3 and w4, the first brake control 300 and the second brake control 400 open the valves to be passed through, which include the first main control valve 191, the mixing valve 193, the third inlet valve 183, the fourth inlet valve 184, the first traction control valve 291, the second traction control valve 292, the fifth inlet valve 283 and the sixth inlet valve 284.

[0085] When the first brake unit 100 is operating normally, the hydraulic motor 210 of the second brake unit 200 is not operating. The first brake controller 300 controls the pressure reducing valve 194.

[0086] If an abnormality occurs in the operation of the first brake unit and the driver does not intervene in braking, the flow of hydraulic pressure may be as shown in Fig. 5, which will now be described.

[0087] In this case, the first brake controller 300 does not actuate the actuator 150 of the first brake unit 100. The second brake controller 400 controls the closing of the first traction control valve 291 and the second traction control valve 292. In addition, the second brake controller 400 controls the opening of the first high-pressure switching valve 241 and the second high-pressure switching valve 242. The second brake controller 400 controls the operation of the hydraulic motor 210 of the second brake unit 200.

[0088] The first and second hydraulic pumps 211 and 212, located on the left and right sides of the hydraulic motor 210, are driven by the hydraulic motor. The first and second hydraulic pumps 211 and 212 supply hydraulic pressure to the third and fourth wheel brakes w3 and w4 using the hydraulic oil supplied from the third main flow path 260.

[0089] Since the first brake unit 100 is not operating normally, control is transferred to the second brake controller 400 via the pressure reducing valve 194 located above the backup brake cylinder 110. However, if the driver does not intervene in braking, the second brake controller 400 does not need to control the pressure reducing valve 194.

[0090] Braking of the first and second wheels can be controlled using the EPB controller 600 and the EPB operator 500. In other words, the braking force of the first and second wheels is controlled by the EPB operator 500, and the braking force of the third and fourth wheels is controlled by the second brake unit 200.

[0091] When an abnormality occurs in the operation of the first brake unit 100 and the driver intervenes in the vehicle braking, the flow of hydraulic pressure may be reduced as shown in the Fig. 6 and Fig. 7, which will now be described.

[0092] As in Fig. 6, in this case, the first brake controller 300 does not actuate the actuator 150 of the first brake unit 100. However, since the driver has actuated the brake pedal 101, hydraulic oil leaks from the second backup chamber 119 of the backup brake cylinder 110, passes through the fourth backup flow path 176, the first main flow path 165 and the first brake flow path 161, so that the hydraulic oil supplies its hydraulic pressure to the first and second wheel brakes w1 and w2. Since the second brake controller 400 controls the closing of the first and second traction control valves 291 and 292, hydraulic oil discharged from the first backup chamber 118 of the backup brake cylinder 110 can pass through the third backup flow path 175, the second main flow path 166 and the second brake flow path 163, but is not directed to the second brake unit 200.

[0093] The third and fourth wheel brakes w3 and w4 can be activated by the second brake control 400, which controls the second brake unit 200 as described with reference to Fig. 5. As described with reference to Fig. 5, the first and second wheels can also be braked by the EPB operator 500.

[0094] Here, since the first brake unit 100 is not applied, the amount of hydraulic pressure supplied to the first and second wheel brakes w1 and w2 cannot be adjusted. Since the braking force of the first and second wheel brakes w1 and w2 cannot be fully controlled, the vehicle may be susceptible to a wheel lock phenomenon that occurs when braking on a low-friction road surface. Here, wheel lock is a phenomenon in which the wheel stops rotating when the vehicle is braked. When wheel lock occurs, the vehicle loses its steering ability, increasing the risk of an accident.

[0095] Fig. 7 discloses a method for preventing such a wheel lock phenomenon. When an abnormality occurs in the operation of the first brake unit 100, control is transferred to the second brake controller 400 via the pressure reducing valve 194. Accordingly, the second brake controller 400 can reduce the hydraulic pressure supplied to the first and second wheel brakes w1 and w2 by controlling the opening and closing of the pressure reducing valve 194. When an abnormal operation of the first brake unit 100 occurs and the driver intervenes in braking, the second brake controller 400 opens the pressure reducing valve 194 to allow the reservoir to recover hydraulic oil from the second backup chamber 119 of the backup brake cylinder 110, thereby reducing the hydraulic pressure supplied to the first and second wheel brakes w1 and w2.

[0096] Fig. 8 discloses another method for preventing such a wheel locking phenomenon. In contrast to the disclosure in Fig. 7 shows Fig. 8 illustrates a method for preventing wheel lock by connecting the second brake controller 400 in parallel with the first outlet valve 185 and the second outlet valve 186 instead of the pressure reducing valve 194. When the first brake unit 100 is operating normally, the first and second outlet valves 185 and 186 are controlled by the first brake controller 300. However, when an abnormality occurs in the operation of the first brake unit 100, control is transferred to the second brake controller 400 via the first and second outlet valves 185 and 186. Therefore, the second brake controller 300 can control the opening and closing of the first and second outlet valves 185 and 186, thereby reducing the hydraulic pressure supplied to the first and second wheel brakes w1 and w2.When abnormal operation of the first brake unit 100 occurs and the driver intervenes in braking, the second brake controller 400 opens the first and second outlet valves 185 and 186 to allow the reservoir to recover hydraulic oil from the second backup chamber 119 of the backup brake cylinder 110, thereby reducing the hydraulic pressure supplied to the first and second wheel brakes w1 and w2.

[0097] The Fig. The embodiment disclosed in Figure 8 requires that the two valves are connected in parallel with the second brake control 400, which is more than compensated by preventing the wheel locking phenomenon of the first and second wheels without requiring a new valve as in the embodiment of Figure 8. Fig. 7 to add.

[0098] Although not shown, the second brake control 400 may be implemented by consolidating the embodiments of the Fig. 7 and Fig. 8 may be arranged to control not only the pressure reducing valve 194 but also the first and second outlet valves 185 and 186 to provide greater reliability to the vehicle braking device 1000.

[0099] Fig. 9 shows a flowchart of a braking method according to at least one embodiment of the present disclosure.

[0100] It is determined whether a braking situation has occurred while the vehicle was traveling (S10). If it is determined that no braking situation has occurred while the vehicle was traveling, step S10 is repeated. Although not in Fig. 8, the present algorithm is terminated when the vehicle has finished traveling during the repetition of step S10.

[0101] If it is determined that a braking situation has occurred while the vehicle is traveling, it is determined whether the first brake unit 100 is operating normally (S20). If it is determined that the first brake unit 100 is operating normally, the first brake unit 100 performs control to regulate the hydraulic pressure supplied to the plurality of wheel brakes w1, w2, w3, and w4 (S30).

[0102] After step S30, it is determined whether the vehicle has completed the trip (S40). If it is determined that the vehicle has not completed the trip, the process returns to step S10. If it is determined that the vehicle has completed the trip, the algorithm is terminated.

[0103] If it is determined in step S20 that the first brake unit 100 is not operating normally, the second brake unit 200 performs control to regulate the hydraulic pressure supplied to the third and fourth wheel brakes w3 and w4 (S21).

[0104] It is determined whether the driver intervenes in the braking situation by operating the brake pedal 101, while the second brake unit 200 controls the hydraulic pressure supplied to the third and fourth wheel brakes w3 and w4 (S22).

[0105] If it is determined that the driver has intervened in the braking situation, the opening / closing of the pressure reducing valve 194 is controlled so that the wheel locking phenomenon does not occur at the first and second wheels (S23). If it is determined that the driver has not intervened in the braking situation, step S23 is skipped.

[0106] The electronic parking brake (EPB) controls the braking force of the first wheel and the second wheel (S24). Steps S21 to S23 and S24 are not necessarily performed in the order shown in the drawings, but can be performed simultaneously or in reverse order.

[0107] After step S24, it is determined whether the vehicle has completed the trip (S25). If it is determined that the vehicle has not completed the trip, the process returns to step S21. If it is determined that the vehicle has completed the trip, the algorithm is terminated.

[0108] As described above, according to some embodiments of the present disclosure, when the first brake unit 100 has a failure, the wheel locking phenomenon of the first wheel and the second wheel can be prevented without adding new components in the second brake unit 200 to reduce its manufacturing cost.

[0109] As described above, according to some embodiments of the present disclosure, when abnormal operation of the first brake unit occurs and the vehicle is suddenly braked by means of the second brake unit, the vehicle brake device can prevent wheel locks caused by the driver's operation of the brake pedal by reducing the hydraulic pressure supplied to the remaining wheel brakes not controlled by the second brake unit by controlling the opening and closing of the pressure reducing valve.

[0110] As described above, according to some embodiments of the present disclosure, when abnormal operation of the first brake unit occurs and the vehicle is suddenly braked by means of the second brake unit, the vehicle brake device can prevent wheel locks caused by the driver's operation of the brake pedal by reducing the hydraulic pressure supplied to the remaining wheel brakes not controlled by the second brake unit by controlling the opening and closing of the first and second exhaust valves.

[0111] Although embodiments of the present disclosure have been described for illustrative purposes, it will be apparent to those skilled in the art that various modifications, additions, and substitutions are possible without departing from the spirit and scope of the claimed invention. Therefore, embodiments of the present disclosure have been described for the sake of conciseness and clarity. The scope of the technical idea of the present embodiments is not limited by the illustrations. Accordingly, one skilled in the art would understand that the scope of the claimed invention is not limited by the embodiments expressly described above, but rather by the claims and their equivalents.

Claims

[1] Braking device (1000) for a vehicle having a first wheel brake (w1), a second wheel brake (w2), a third wheel brake (w3) and a fourth wheel brake (w4) for vehicle braking, the braking device (1000) comprising: a first brake controller (300) configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation; a first brake unit (100) comprising a reservoir, a backup brake cylinder (110), a master brake cylinder (120), and a pressure reducing valve (194) disposed between the reservoir and the backup brake cylinder (110), and configured to respond to the first valve opening / closing signal to control a valve between open and closed states and to supply a hydraulic braking force corresponding to the first hydraulic braking signal to the first to fourth wheel brakes (w1,w2,w3,w4); a second brake controller (400) configured to respond to an abnormal operation occurring in the first brake unit (100) to generate a second hydraulic brake signal and a second valve opening / closing signal instead of the first brake controller (300) generating the first hydraulic brake signal and the first valve opening / closing signal; and a second brake unit (200) configured to respond to the second valve opening / closing signal to control a valve between an open and closed state and to supply a hydraulic braking force corresponding to the second hydraulic braking signal to the third wheel brake (w3) and the fourth wheel brake (w4), wherein the second brake controller (400) is configured to respond to an abnormal operation occurring in the first brake unit (100) to take over control of opening and closing the pressure reducing valve (194) from the first brake controller (300) and to relieve a hydraulic pressure supplied to the first wheel brake (w1) and the second wheel brake (w2) when the second brake unit (200) is driven. [2] A braking device according to claim 1, wherein the first braking unit (100) further comprises: a main control valve (191,192) configured to regulate a hydraulic pressure supplied from the backup brake cylinder (110) or the master brake cylinder (120); and a backup valve configured to regulate hydraulic pressure between the backup brake cylinder (110) and the master brake cylinder (120). [3] A braking device according to claim 1, wherein the second braking unit (200) further comprises: a traction control valve (291,292) configured to control a hydraulic pressure supplied to the second brake unit (200) from the first brake unit (100); a high-pressure changeover valve (241, 242) configured to regulate a hydraulic pressure supplied to the second brake unit (200) from the reservoir; and a hydraulic motor (210) and a hydraulic pump adapted to drive the second brake unit (200). [4] A braking device according to claim 3, wherein the second brake controller (400) is configured to respond to an abnormal operation when it occurs in the first brake unit (100) to send a valve opening / closing signal for closing the traction control valve (291,292) and for opening the high-pressure switching valve (241,242) to the second brake unit (200). [5] A braking device according to claim 3, wherein the second brake controller (400) is configured to respond to an abnormal operation when it occurs in the first brake unit (100) and a driver operates a brake pedal (101) to send a valve opening / closing signal for opening the pressure reducing valve (194) to the pressure reducing valve (194). [6] Braking device according to claim 1, further comprising: an electronic parking brake (EPB) controller (600) and an EPB operator (500) configured to be associated with a first wheel and supply braking force to a second wheel using a motor, wherein the EPB controller (600) is configured to respond to abnormal operation occurring in the first braking unit (100) to send a braking signal to the EPB operator (500) for braking the first wheel and the second wheel. [7] Braking device according to claim 6, further comprising: a communication unit (700) configured and arranged to transmit and receive information about abnormal operation of the first brake unit (100), the second brake unit (200), and the EPB operator (500) between the first brake controller (300), the second brake controller (400), and the EPB controller (600). [8] Method for controlling a braking device (1000) for a vehicle having a first wheel brake (w1), a second wheel brake (w2), a third wheel brake (w3) and a fourth wheel brake (w4) for vehicle braking, the method comprising: Determining whether a first braking unit (100) is operating normally when it is determined that a braking situation has occurred while the vehicle is traveling; Braking the vehicle when it is determined that the first brake unit (100) is not operating normally by supplying hydraulic pressure to the third wheel brake (w3) and the fourth wheel brake (w4) by actuating a second brake unit (200); and Preventing wheel locking of the first wheel and the second wheel provided on the vehicle by opening a pressure reducing valve (194) when it is detected that a driver has intervened in the braking situation. [9] The method of claim 8, wherein braking the vehicle further comprises: Actuating the second brake unit (200) and simultaneously braking the first wheel and the second wheel using an electronic parking brake (EPB) operator (500). [10] The method of claim 8, wherein braking the vehicle comprises: Closing the traction control valve (291, 292) by the second brake unit (200) to regulate a hydraulic pressure supplied to the second brake unit (200) from the first brake unit (200); and Opening a high pressure switching valve by the second brake unit (200) to regulate a hydraulic pressure supplied to the second brake unit from a reservoir. [11] Braking device (1000) for a vehicle having a first wheel brake (w1), a second wheel brake (w2), a third wheel brake (w3) and a fourth wheel brake (w4) for vehicle braking, the braking device (1000) comprising: a first brake controller (300) configured to generate a first hydraulic brake signal and a first valve opening / closing signal for braking the vehicle in the vehicle braking situation; a first brake unit (100) having first to fourth inlet valves (181, 182, 183, 184) and a first outlet valve (184), a second outlet valve (185), a third outlet valve (186) and a fourth outlet valve (187) arranged to regulate a hydraulic pressure supplied to the first to fourth wheel brakes, and adapted to respond to the first valve opening / closing signal, to control a valve between open and closed state and supplying a hydraulic braking force corresponding to the first hydraulic braking signal to the first to fourth wheel brakes (w1,w2,w3,w4); a second brake control (400) configured to respond to abnormal operation occurring in the first brake unit (100), to generate a second hydraulic brake signal and a second valve opening / closing signal instead of the first brake controller (300) generating the first hydraulic brake signal and the first valve opening / closing signal; and a second brake unit (200) configured to respond to the second valve opening / closing signal to switch a valve between open and closed state and to supply a hydraulic braking force corresponding to the second hydraulic braking signal to the third wheel brake (w3) and the fourth wheel brake (w4), wherein the second brake controller (400) is configured to respond to an abnormal operation occurring in the first brake unit (100) to take over control of opening and closing of the first exhaust valve (184) and the second exhaust valve (185) from the first brake controller (300) and to relieve a hydraulic pressure supplied to the first wheel brake (w1) and the second wheel brake (w2) when the second brake unit (200) is driven.

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