Patent Publication Number: US-2022234561-A1

Title: Method and apparatus for controlling electric hydraulic brake

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on, and claims priority from, Korean Patent Application Number 10-2021-0009393, filed Jan. 22, 2021, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The present disclosure in some embodiments relates to an electric hydraulic brake apparatus and a control method for the same. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. 
     An autonomous driving vehicle is capable of responding to a malfunction of its main braking system by employing an auxiliary braking system disposed between the main braking system and a plurality of wheel brake mechanisms to secure a fail-safe operation. 
     Conventionally, an auxiliary braking system performs 2-channel pressure boost/deboost control and two-channel depressurization control. For example, a conventional auxiliary braking system performs functions of increasing/decreasing braking pressure of front vehicle wheels and braking depressurization of rear wheels. For this purpose, a total of eight conduits of four input conduits and four output conduits need to be connected to the auxiliary braking system. 
     However, when the main braking system is normal, it delivers brake fluid to a plurality of wheel brake mechanisms by routing the brake fluid to pass through a plurality of solenoid valves installed in the auxiliary braking system. The involvement of a plurality of solenoid valves to deliver the brake fluid therethrough leads to a degradation in hydraulic response performance. 
     Furthermore, the auxiliary braking system is equipped with a plurality of solenoid valves involved in anti-lock braking (ABS) control. Multiple solenoid valves involved in the ABS control have a limited orifice size which aggravates the degraded hydraulic response performance. 
     SUMMARY 
     According to at least one embodiment, the present disclosure provides an electric hydraulic brake apparatus including a reservoir, a plurality of wheel brake mechanisms, a main braking system, and an auxiliary braking system. The reservoir is configured to store brake fluid. The plurality of wheel brake mechanisms is configured to provide a braking force by providing hydraulic pressure to a plurality of vehicle wheels. The main braking system is disposed between the reservoir and the plurality of wheel brake mechanisms and is configured to deliver the brake fluid discharged from the reservoir to the plurality of wheel brake mechanisms. The auxiliary braking system is disposed between the main braking system and the plurality of wheel brake mechanisms and is configured to supply the brake fluid to the plurality of wheel brake mechanisms when a failure occurs in the main braking system. Here, the auxiliary braking system includes a first hydraulic pressure input unit and a second hydraulic pressure input unit configured to receive the brake fluid from booster valves installed in the main braking system, a third hydraulic pressure input unit configured to receive the brake fluid from the main braking system without passing through the booster valves, a first inlet line and a second inlet line configured to transfer a hydraulic pressure between the main braking system and the plurality of wheel brake mechanisms, and a split line configured to receive the brake fluid delivered from the third hydraulic pressure input unit and supply the brake fluid to the plurality of wheel brake mechanisms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a conceptual diagram of an electric hydraulic brake apparatus according to at least one embodiment of the present disclosure. 
         FIG. 2  is a hydraulic circuit diagram of an electric hydraulic brake apparatus according to at least one embodiment of the present disclosure. 
         FIG. 3  is a hydraulic circuit diagram of an electric hydraulic brake apparatus with a main braking system when in a normal condition supplying brake fluid to front and rear wheel brakes, according to at least one embodiment of the present disclosure. 
         FIG. 4  is a hydraulic circuit diagram of an electric hydraulic brake apparatus with the main braking system when in failure, supplying brake fluid to a front-wheel brake by using an auxiliary braking system, according to at least one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Accordingly, the present disclosure seeks to provide an electric hydraulic brake apparatus wherein brake fluid, when supplied by the main braking system to an auxiliary braking system, is arranged not to pass through a specific solenoid valve installed in the auxiliary braking system but to be delivered by using a split line to a plurality of wheel brake mechanisms, thereby increasing hydraulic response performance. 
     Additionally, the present disclosure seeks to provide an electric hydraulic brake apparatus with an on-off valve having a large orifice size installed upstream of a split line to further enhance the hydraulic response performance. 
     Some exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings. In the following description, like reference numerals preferably designate like elements, although the elements are shown in different drawings. Further, in the following description of some embodiments, a detailed description of known functions and configurations incorporated herein will be omitted for clarity and brevity. 
     Alphanumeric codes such as first, second, i), ii), a), b), etc., in describing components of embodiments of the present disclosure are used solely for differentiating one component from the other but not to imply or suggest the substances, the order, or sequence of the components. Throughout this specification, when a part “includes” or “comprises” a component, the part is meant to further include other components, not excluding thereof unless there is a particular description contrary thereto. 
     In the present disclosure, as to the relative position in the flow path or line, “in front of” or “upstream” refers to a portion wherein the brake fluid flows, which is closer to a reservoir  10 , and “behind” or “downstream” refers to a portion that is farther from the reservoir  10 . However, the term, upstream or downstream refers not only to upstream or downstream one of successive line portions literally but also to relatively upstream or downstream one of discrete line portions that are spaced apart. 
       FIG. 1  is a conceptual diagram of an electric hydraulic brake apparatus according to at least one embodiment of the present disclosure. 
       FIG. 2  is a hydraulic circuit diagram of an electric hydraulic brake apparatus according to at least one embodiment of the present disclosure. 
     It should be understood that the hydraulic circuit diagram shown in  FIG. 2  is merely conceptually showing the respective components for convenience of explanation and the position of the actual hydraulic pressure block and the lines formed inside the hydraulic pressure block is subject to change. 
     The present disclosure provides an electric hydraulic brake apparatus  1  including, among other components, the reservoir  10 , a brake pedal  11 , and a main braking system  20 , which have arrangements and components available for a person skilled in the art to readily implement, so need not be elaborated herein by further illustrations or descriptions. 
     Additionally, the present disclosure includes wheel brake mechanisms with hydraulic pressure adjusted by an auxiliary braking system  100 , which are illustrated as a front right wheel brake mechanism (FR) and a front left wheel brake mechanism (FL), but the merely illustrative wheel brake mechanisms may be modified to be any two of the front right wheel brake mechanism, front left wheel brake mechanism, rear right wheel brake mechanism, and rear left wheel brake mechanism. 
     As shown in  FIGS. 1 and 2 , the electric hydraulic brake apparatus  1  may include all or some of the reservoir  10 , the brake pedal  11 , the main braking system  20 , and the auxiliary braking system  100 . 
     The reservoir  10  is configured to store brake oil therein. 
     When activated by a user&#39;s pedaling, the brake pedal  11  causes a piston disposed inside of a master cylinder (both not shown) of the main braking system  20  to perform a translational motion. 
     The electric hydraulic brake apparatus  1  includes multiple wheel brake mechanisms FR, FL, RR, and RL which apply a braking force to multiple wheels (not shown) by using the hydraulic pressure of the brake fluid discharged from the reservoir  10 . When the driver depresses the brake pedal  11 , an electronic control unit (not shown) detects the driver&#39;s braking request by using a pedal travel sensor (PTS). Upon detecting the driver&#39;s braking request, the electronic control unit generates a braking signal. Here, the braking signal is an electric signal transmitted for causing the respective braking systems  20  and  100  to generate a braking force corresponding to the amount of depression of the brake pedal  11  by the driver. 
     The main braking system  20  is disposed between the reservoir  10  and the multiple wheel brake mechanisms FR, FL, RR, RL, and it is configured to transfer the brake fluid discharged from the reservoir  10  to the multiple wheel brake mechanisms FR, FL, RR, RL and to control the hydraulic pressure of the brake fluid. When a failure occurs in at least some of the components of the main braking system  20 , the electronic control unit transmits an auxiliary braking signal to the auxiliary braking system  100 . The auxiliary braking signal when transmitted by the electronic control unit to the auxiliary braking system  100  operates all or some of the components of the auxiliary braking system  100 . This arrangement of the present disclosure provides fail-safe operability of the electric hydraulic brake apparatus  1 . 
     The auxiliary braking system  100  is disposed between the main braking system  20  and the multiple wheel brake mechanisms FR and FL. During autonomous vehicle driving, when an abnormality occurs in the main braking system  20 , or when a driver directly intervenes in braking, the auxiliary braking system  100  is operated in response to an abnormality occurring in the main braking system  20 . 
     The auxiliary braking system  100  includes all or some of hydraulic pressure input units  101 ,  102 ,  103 ,  104 , hydraulic pressure output units  105 ,  106 , inlet lines  111 ,  112 , a split line  113 , an actuating unit  30 , traction control valves TCV 1 , TCV 2 , inlet valves FLIV, FRIV, outlet lines  121 ,  122 ,  123 , outlet valves FLOV, FROV, RLOV, accumulators A 1 , A 2 , circulation lines  141 ,  142 , and high pressure switching valves HSV 1 , HSV 2 . 
     One or more of the hydraulic pressure input units  101 ,  102 ,  103 , and  104  are disposed on the lines through which the brake fluid discharged from the main braking system  20  flows into the auxiliary braking system  100 . 
     The inlet lines  111  and  112  are in fluid communication with the main braking system  20  by the hydraulic pressure input units  101 ,  102 ,  103 , and  104 . To this end, hydraulic pressure input units  101 ,  102 ,  103 , and  104  are disposed in the auxiliary braking system  100 . The auxiliary braking system  100  according to at least one embodiment of the present disclosure includes the first inlet line  111 , the second inlet line  112 , and the split line  113 , and further includes the first hydraulic pressure input unit  101 , the second hydraulic pressure input unit  102 , and the third hydraulic pressure input unit  103 . 
     The first hydraulic pressure input unit  101  receives the brake fluid from a front left wheel booster valve INFL installed in the main braking system  20 . The second hydraulic pressure input unit  102  receives the brake fluid from the front right wheel booster valve INFR installed in the main braking system  20 . The third hydraulic pressure input unit  103  is connected to a line split valve LSV installed in the main braking system  20  to receive the brake fluid from the main braking system  20 . The fourth hydraulic pressure input unit  104  receives the brake fluid directly from the reservoir  10 . 
     One or more of the hydraulic pressure output units  105  and  106  are disposed on the lines for allowing the brake fluid discharged from the auxiliary braking system  100  to flow into the multiple wheel brake mechanisms FR and FL. Thanks to the hydraulic pressure output units  105  and  106 , the inlet lines  111  and  112  are in fluid communication with the multiple wheel brake mechanisms FR and FL. The auxiliary braking system  100  according to at least one embodiment includes the first hydraulic pressure output unit  105  and the second hydraulic pressure output unit  106 . 
     Formed between the hydraulic pressure input units  101 ,  102  and the hydraulic pressure output units  105 ,  106 , the inlet lines  111 ,  112  transfer the brake fluid discharged from the main braking system  20  to the front-wheel brake mechanisms FL, FR, respectively. The inlet lines  111 ,  112  include the first inlet line  111  and the second inlet line  112 . 
     The first inlet line  111  is configured to deliver all or some of the brake fluid discharged from the main braking system  20  to the front left wheel brake mechanism FL. Additionally, the second inlet line  112  is configured to deliver all or some of the brake fluid from the main braking system  20  to the front right wheel brake mechanism FR. 
     On the other hand, the split line  113  is configured to transmit all or some of the brake fluid discharged from the main braking system  20  to the front right wheel brake mechanism FR and the front left wheel brake mechanism FL. More particularly, the split line  113  has one end branched from the line at its point that is installed with the line split valve LSV of the main braking system  20  and the other end that is in fluid communication with the first inlet valve FLIV and the second inlet valve FRIV. 
     The hydraulic pressure of the fluid flowing inside the first inlet line  111  and the second inlet line  112  may be increased by the actuating unit  30 . The actuating unit  30  includes a motor configured to drive a first pump SP 1  and/or a second pump SP 2 . The first pump SP 1  has its outlet connected to a point of the first inlet line  111 . The second pump SP 2  has its outlet connected to a point of the second inlet line  112 . At least one of the first pump SP 1  and the second pump SP 2  when driven may increase the internal hydraulic pressure of at least one of the inlet lines  111  and  112  connected to the respective pumps SP 1  and SP 2 . 
     Disposed at a point on the first inlet line  111  is a first traction control valve TCV 1  which controls the opening and closing of the first inlet line  111 . In this case, the first traction control valve TCV 1  is disposed in front of a junction between the first inlet line  111  and the outlet of the first pump SP 1 . The first traction control valve TCV 1  is configured in a normally open type. Accordingly, in the non-powered mode when no auxiliary braking signal is applied, the first traction control valve TCV 1  is opened. The first traction control valve TCV 1  when closed may block some of the brake fluid that is pressure boosted by the first pump SP 1  from flowing back to the main braking system  20 . 
     Disposed at another point on the first inlet line  111  is a first inlet valve FLIV which controls the opening and closing of the first inlet line  111 . Meanwhile, the first inlet valve FLIV is disposed behind the junction between the first inlet line  111  and the outlet of the first pump SP 1 . The first inlet valve FLIV is configured in a normally open type. Accordingly, in the non-power mode with no auxiliary braking signal applied, the first inlet valve FLIV is opened. The first inlet valve FLIV when closed may block some of the brake fluid that is pressure boosted by the first pump SP 1  from being transmitted to the front left wheel brake mechanism FL. In this way, pressure control of brake fluid can be performed by opening and closing the inlet valves. 
     For details on the second inlet line  112 , the second traction control valve TCV 2 , and the second inlet valve FRIV, reference can be made to their corresponding descriptions on the first inlet line  111 , the first traction control valve TCV 1 , and the first inlet valve FLIV. 
     The split line  113  is configured to deliver all or some of the brake fluid discharged from the main braking system  20  to the front left wheel brake mechanism FL and the front right wheel brake mechanism FR. When a main braking signal is applied to the main braking system  20  by the electronic control unit, using the split line  113  connected to the third hydraulic pressure input unit  103 , the brake fluid can be transmitted to the front left wheel brake mechanism FL and the front right wheel brake mechanism FR without passing through the first traction control valve TCV 1  and the second traction control valve TCV 2 . Here, the main braking signal is a signal for the electronic control unit to control the main braking system  20  to brake the vehicle. On the other hand, the auxiliary braking signal is a signal for the electronic control unit to control the auxiliary braking system  100  to brake the vehicle when a failure occurs in the main braking system  20 . 
     If it were a conventional auxiliary braking system that lacks the split line  113 , when the main braking system  20  delivers the brake fluid to the front left wheel brake mechanism FL and the front right wheel brake mechanism FR, the brake fluid would need to pass through the first traction control valve TCV 1  and the second traction control valve TCV 2 . Additionally, the brake fluid flows into the auxiliary braking system  100  by passing through the front-wheel booster valves INFL and INFR of the main braking system  20 . 
     However, if the brake fluid were made to pass through the first traction control valve TCV 1  and the second traction control valve TCV 2  or through the front-wheel booster valves INFL and INFR, the electric hydraulic brake apparatus would have a hydraulic response delay. The hydraulic response performance is inversely proportional to the delay time that occurs in the process of transferring the hydraulic pressure to the wheel brake mechanisms when the electronic control unit brakes the vehicle by using the main braking signal. In other words, the longer the delay time, the lower the hydraulic response performance, and the shorter the delay time, the better the hydraulic response performance. 
     Therefore, the auxiliary braking system  100  according to at least one embodiment of the present disclosure further includes the third hydraulic pressure input unit  103  and the split line  113 , thereby improving hydraulic response performance when the main braking signal is applied. 
     On the split line  113  of the auxiliary braking system  100 , an on-off valve  103   a  is installed. The on/off valve  103   a  may be, for example, a normally open type solenoid valve or a check valve. The check valve is a valve that prevents a reverse flow of brake fluid in the line. For example, the check valve is designed so that the brake fluid does not flow from the auxiliary braking system  100  to the main braking system  20 . 
     The auxiliary braking system  100  according to at least one embodiment of the present disclosure can further improve the hydraulic response performance by opening or closing the split line  113  by using the on-off valve  103   a.    
     Used for the on-off valve  103   a  may be a solenoid valve having a large orifice size, unlike a general solenoid valve, for example, an inlet valve or an outlet valve. Here, the orifice size means the cross-sectional area of the solenoid valve at the point where the brake fluid is discharged through the solenoid valve. 
     The brake fluid flowing into the auxiliary braking system  100  passes through the on-off valve  103   a  having a large orifice size so that the brake fluid is quickly transferred to the front-wheel brake mechanisms FL and FR. Therefore, the on-off valve  103   a  having a large orifice size can further improve the hydraulic response performance. 
     The outlet lines  121 ,  122 ,  123  include the first outlet line  121 , the second outlet line  122 , and the third outlet line  123 . 
     The first outlet line  121  and the second outlet line  122  are each configured to be connected to a point of the first inlet line  111  or the second inlet line  112  so that the first inlet line  111  or the second inlet line  112  have its brake fluid at least partially branched off. 
     The first outlet line  121  has one end connected to a bifurcation formed on the first inlet line  111  downstream of the first inlet valve FLIV and the other end connected to an inlet of the first pump SP 1 . 
     The first outlet line  121  is installed at a point with a first outlet valve FLOV which controls the opening and closing of the first outlet line  121 . The first outlet valve FLOV is configured in a normal-close type. Accordingly, in the non-power mode with no auxiliary braking signal being applied, the first outlet valve FLOV is closed. The first outlet valve FLOV when opened discharges at least some of the pressure boosted brake fluid flowing through the first inlet line  111  to the first outlet line  121 . This may reduce the hydraulic pressure transmitted to the front left wheel brake mechanism FL. 
     The first outlet line  121  may be further installed at another point with the first accumulator A 1  downstream of the first outlet valve FLOV. The first accumulator A 1  is configured to temporarily receive all or some of the brake fluid delivered from the first outlet line  121 . This configuration can minimize damage to the first outlet line  121  due to hydraulic pulsation of the brake fluid. Here, the damage occurring to the first outlet line  121  means, for example, that the line when exposed to continuous pulsation for a long time suffers from fatigue, deformation, abrasion, or other degradation occurring in at least a part thereof. 
     For details on the second outlet line  122 , the second outlet valve FROV, and the second accumulator A 2 , reference can be made to their corresponding descriptions on the first outlet line  121 , the first outlet valve FLOV, and the first accumulator A 1 . 
     Meanwhile, the third outlet line  123  is connected to the rear left wheel brake mechanism RL to depressurize the brake fluid supplied thereto. The detailed description of the present disclosure illustrates a configuration with the rear left wheel brake mechanism RL, although another embodiment of the present disclosure may have the third outlet line  123  connected to the rear right wheel brake mechanism RR. 
     On the other hand, the electronic control unit (not shown) of the auxiliary braking system  100  according to at least one embodiment determines whether to use the accumulators A 1  and A 2  according to the required braking quantity. For example, in case of slow braking, only some of the outlet valves FLOV, FROV, RLOV is opened for allowing some limited brake fluid to pass through the thus opened outlet lines among the outlet lines  121 ,  122 ,  123 , while allowing the brake fluid to be branched off from the inlet lines  111  and  112 . At this time, since the amount of the brake fluid that is branched off is relatively small compared to when making a sudden braking, the brake fluid needs not to be accommodated in the accumulators A 1  and A 2 . However, in the case of sudden braking, all of the outlet valves FLOV, FROV, and RLOV are opened for allowing the brake fluid to pass through all of the outlet lines  121 ,  122 , and  123  and branches off from the inlet lines  111  and  112 . At this time, since the amount of the branched brake fluid is larger than that of slow braking, the brake fluid is received in the accumulators A 1  and A 2 . 
     The third outlet line  123  has one end connected to a point on the line connected to the rear left wheel brake and the other end connected to the first outlet line  121 . At this time, the junction between the third outlet line  123  and the first outlet line  121  is formed downstream of the first outlet valve FLOV. For this reason, the brake fluid delivered by the third outlet line  123  may merge with the brake fluid flowing inside the first outlet line  121 . 
     The third outlet line  123  leads to one or more of the first outlet line  121  and the second outlet line  122 . For example, as shown in  FIG. 2  of the present embodiment, the first outlet line  121  and the second outlet line  122  are interconnected, and they may be in fluid communication with each other. In this case, the brake fluid delivered by the third outlet line  123  may be received in at least one of the first accumulator A 1  and the second accumulator A 2 . However, the present disclosure is not necessarily limited to this configuration, and the first outlet line  121  and the second outlet line  122  may not be interconnected, wherein the brake fluid delivered by the third outlet line  123  merges only with the first outlet line  121  and is received in the first accumulator A 1 . Meanwhile, in another embodiment not including the accumulators A 1  and A 2 , the third outlet line  123  may be designed to render the brake fluid to be recovered to the reservoir. 
     The third outlet line  123  is installed at one point with the third RLOV which controls the opening and closing of the third outlet line  123 . The third outlet valve RLOV is formed in a normal-close type. Accordingly, in the non-power mode, the third outlet valve RLOV is closed. 
     The first circulation line  141  is installed at one point with the first high pressure switching valve HSV 1  which controls the opening and closing of the first circulation line  141 . The first high-pressure switching valve HSV 1  is formed in a normal-close type. Therefore, in the non-power mode, the first high-pressure switching valve HSV 1  is closed. When the first high-pressure switching valve HSV 1  is opened, the brake fluid is provided to the actuating unit  30 . 
     For details on the second circulation line  142  and the second high-pressure switching valve HSV 2 , reference can be made to their corresponding descriptions on the first circulation line  141  and the first high-pressure switching valve HSV 1 . 
       FIG. 3  is a hydraulic circuit diagram of an electric hydraulic brake apparatus with a main braking system when in a normal condition supplying brake fluid to front and rear-wheel brakes, according to at least one embodiment of the present disclosure. 
     In  FIG. 3 , fluid lines indicated by a thick solid line indicate lines through which brake fluid flows. 
     The electronic control unit generates a braking signal based on the drivers braking request and supplies the brake fluid to the multiple wheel brake mechanisms FL, FR, RL, and RR. 
     The electronic control unit may perform a failure determination process of determining whether the main braking system  20  is normal before supplying the brake fluid to the multiple wheel brake mechanisms FL, FR, RL, RR. In particular, upon determining that the main braking system  20  is normal, the electronic control unit uses the same system  20  to supply the brake fluid to the wheel brake mechanisms FL, FR, RL, and RR. 
     When the main braking system  20  is normal, the electronic control unit transmits a main braking signal to the main braking system  20  for controlling to supply the brake fluid to the multiple wheel brake mechanisms FL, FR, RL RR. For example, the electronic control unit controls main braking rear-wheel booster valves INRL and INRR of the main braking system  20  and thereby controls to supply the brake fluid to the rear-wheel brake mechanisms RL and RR. Additionally, the electronic control unit uses the split line  113  for controlling to supply the brake fluid to the front-wheel brake mechanisms FL and FR. Here, when the electronic control unit boosts the pressure of the front-wheel brake mechanisms FL and FR, the brake fluid passes neither the front-wheel booster valves INFL and INFR installed in the main braking system  20  nor the traction control valves TCV 1  and TCV 2  installed in the auxiliary braking system  100 . This allows the electric hydraulic brake apparatus  1  according to at least one embodiment of the present disclosure to increase hydraulic response performance when boosting the pressure for the front-wheel brake mechanisms FL and FR. 
     Additionally, with a solenoid valve having a large orifice size used as the on-off valve  103   a , the present disclosure can further increase the hydraulic response performance when boosting the pressure for the front-wheel brake mechanisms FL and FR. 
       FIG. 4  is a hydraulic circuit diagram of an electric hydraulic brake apparatus with the main braking system when in failure, supplying brake fluid to a front-wheel brake by using an auxiliary braking system, according to at least one embodiment of the present disclosure. 
     In  FIG. 4 , fluid lines indicated by a thick solid line indicate lines through which brake fluid flows. 
     When the main braking system  20  is in a failure, the electronic control unit transmits a main braking signal to the auxiliary braking system  100  for controlling to supply the brake fluid to the front-wheel brake mechanisms FL and FR. Additionally, the electronic control unit brakes the rear wheels by using an electronic parking brake. 
     The auxiliary braking system  100  according to at least one embodiment of the present disclosure does not participate in the pressure boost control for the rear left wheel brake mechanism RL and the rear right wheel brake mechanism RR. Particularly, the auxiliary braking system  100  increases and decreases the pressure for two front wheel brake mechanisms and depressurizes one rear wheel brake mechanisms. Additionally, when the main braking system  20  is normal and when the main braking system  20  supplies the brake fluid to the front-wheel brake mechanisms FL and FR, the split line  113  is used to bypass a specific solenoid valve, thereby enhancing the hydraulic operation performance. Additionally, with a valve having a large orifice size used as a valve for opening and closing the split line  113 , the present disclosure can further increase the hydraulic operation performance. 
     As described above, according to some embodiments, the present disclosure can provide an electric hydraulic brake apparatus wherein brake fluid, as supplied by the main braking system to the auxiliary braking system, is arranged not to pass through a specific solenoid valve installed in the auxiliary braking system but to be delivered through the split line to the multiple wheel brake mechanisms, thereby increasing the hydraulic response performance. 
     Additionally, the present disclosure can provide the electric hydraulic brake apparatus with the on-off valve having a large orifice size installed upstream of the split line to further enhance the hydraulic response performance. 
     Although exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the idea and scope of the claimed invention. Therefore, exemplary embodiments of the present disclosure have been described for the sake of brevity and clarity. The scope of the technical idea of the present embodiments is not limited by the illustrations. Accordingly, one of ordinary skill would understand the scope of the claimed invention is not to be limited by the above explicitly described embodiments but by the claims and equivalents thereof.