Patent Publication Number: US-2022212649-A1

Title: 3-way solenoid valve and brake system for vehicle including same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from and the benefit of, Korean Patent Application No. 10-2021-0000805, filed on Jan. 5, 2021, which is hereby incorporated by reference for all purposes as set forth herein in its entirety. 
     BACKGROUND 
     Field 
     Exemplary embodiments relate to a 3-way solenoid valve and a braking system for a vehicle including the same. 
     Discussion of the Background 
     A conventional brake system for vehicle has solenoid valves of normal open type or solenoid valves of normal close type. The solenoid valve of normal open type refers to a solenoid valve in which the flow path is normally open when no current is applied from a control unit. Meanwhile, the solenoid valve of normal close type refers to a solenoid valve in which the flow path is normally closed when no current is applied from the control unit. 
     Accordingly, a conventional brake system for vehicle is equipped with solenoid valves of normal open type and solenoid valves of normal close type to supply hydraulic oil received from a brake device to wheel brakes. 
       FIG. 1  is a block diagram of a brake system for vehicle according to a prior art. 
     Referring to  FIG. 1 , hydraulic oil provided from a brake device  1  is supplied to an inlet valve  3  and an outlet valve  5 . The inlet valve  3  is normal open type and the outlet valve  5  is normal close type. In addition, a check valve  4  that only allows a flow from a wheel cylinder W 1 , W 2 , W 3  or W 4  to the brake device  1  is equipped with the inlet valve  3 . To reduce the hydraulic pressure supplied from the wheel cylinder W 1 , W 2 , W 3  or W 4 , the outlet valve  5  becomes open to discharge the hydraulic oil from the wheel cylinder W 1 , W 2 , W 3  or W 4  to the brake device  1 . 
     As such, the conventional brake system for vehicle must be equipped with the inlet valve  3  of normal open type, the outlet valve  5  of normal close type, and a check valve  4 , so that the number of solenoid valves for implementing the brake system increases, thereby increasing manufacturing cost and increasing volume and weight of the brake system. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and, therefore, it may contain information that does not constitute prior art. 
     SUMMARY 
     An exemplary embodiment of the present invention provides a 3-way solenoid valve including: a valve chamber; a valve block including a first fluid port, a second fluid port, and a third fluid port, each in fluid communication with the valve chamber; a first operation assembly including a first coil, a first armature configured to generate an electromagnetic force when current is supplied to the first coil and having a hollow portion formed in a center of the first armature, a body placed on a lower portion of the first armature and formed to allow at least a portion of the first armature to pass through inside of the body, and a first elastic unit placed between the body and the first armature; a valve seat placed to block flow of fluid between the second fluid port and the third fluid port, and having a hollow portion in a center of the valve seat; and a second operation assembly including a second coil placed above the first coil, a second armature configured to generate an electromagnetic force when current is supplied to the second coil, a fluid control unit placed under a hollow portion of the valve seat to control the amount of fluid flowing to the third fluid port, and a rod placed to pass through the valve seat and the first armature while one end of the rod is in contact with the second armature and the other end of the rod is in contact with the fluid control unit. 
     Another exemplary embodiment of the present invention provides a brake system for vehicle including: one or more wheel cylinders configured to apply braking pressure to each wheel of the vehicle using hydraulic pressure; one or more 3-way solenoid valves configured to be placed to increase or decrease the hydraulic pressure supplied to the one or more wheel cylinders; and a brake device configured to supply hydraulic pressure to the wheel cylinder by using foot pressure applied to a brake pedal or driving a hydraulic pump, wherein the 3-way solenoid valve comprising: a valve chamber; a valve block including a first fluid port, a second fluid port, and a third fluid port, each in fluid communication with the valve chamber; a first operation assembly including a first coil, a first armature configured to generate an electromagnetic force when current is supplied to the first coil and having a hollow portion formed in a center of the first armature, a body placed on a lower portion of the first armature and formed to allow at least a portion of the first armature to pass through inside of the body, and a first elastic unit placed between the body and the first armature; a valve seat placed to block flow of fluid between the second fluid port and the third fluid port, and having a hollow portion in a center of the valve seat; and a second operation assembly including a second coil placed above the first coil, a second armature configured to generate an electromagnetic force when current is supplied to the second coil, a fluid control unit placed under a hollow portion of the valve seat to control the amount of fluid flowing to the third fluid port, and a rod placed to pass through the valve seat and the first armature while one end of the rod is in contact with the second armature and the other end of the rod is in contact with the fluid control unit. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention. 
         FIG. 1  is a block diagram of a brake system for vehicle according to a prior art. 
         FIG. 2  is a cross-sectional view of a 3-way solenoid valve according to an embodiment of the present disclosure. 
         FIG. 3  is a cross-sectional view illustrating flow of fluid when no current is applied to the first coil and the second coil of the 3-way solenoid valve. 
         FIG. 4  is a cross-sectional view illustrating flow of fluid when current is applied to the first coil of the 3-way solenoid valve. 
         FIG. 5  is a cross-sectional view illustrating flow of fluid when current is applied to the first coil and the second coil of the 3-way solenoid valve. 
         FIG. 6  is a block diagram of a brake system for vehicle including the 3-way solenoid valve according to an embodiment of the present disclosure. 
     
    
    
     REFERENCE NUMBERS 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 10a: first coil 
                 10b: second coil 
               
               
                 20a: first armature 
                 20b: second armature 
               
               
                 21: rod 
                 22: orifice 
               
               
                 30a: first elastic unit 
                 30b: second elastic unit 
               
               
                 40: body 
                 50: sealing unit 
               
               
                 60a: first stopper 
                 60b: second stopper 
               
               
                 70: valve seat 
                 80: fluid control unit 
               
               
                 90: valve block 
                 110: first operation assembly 
               
               
                 120: second operation assembly 
                   
               
               
                 200: brake device 
                 W1, W2, W3 or W4: wheel cylinder 
               
               
                 A: first fluid port 
                 B: second fluid port 
               
               
                 C: third fluid port 
                 P1: first flow path 
               
               
                 P2: second flow path 
                 X-Y: X-Y plane 
               
               
                 Z: Z axis 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     Unless defined otherwise, it is to be understood that all the terms (including technical and scientific terms) used in the specification has the same meaning as those that are understood by those who skilled in the art. Further, the terms defined by the dictionary generally used should not be ideally or excessively formally defined unless clearly defined specifically. It will be understood that for purposes of this disclosure, “at least one of X, Y, and Z” can be construed as X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ). Unless particularly described to the contrary, the term “comprise”, “configure”, “have”, or the like, which are described herein, will be understood to imply the inclusion of the stated components, and therefore should be construed as including other components, and not the exclusion of any other elements. 
     The present disclosure in some embodiments seeks to reduce manufacturing cost by replacing the inlet valve and the outlet valve with the 3-way solenoid valve. 
     Further, the present disclosure reduces the volume and weight of the brake system for vehicle by reducing the number of solenoid valves disposed in the brake system. 
     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 the purpose of clarity and for brevity. 
     Additionally, alphanumeric codes such as first, second, i), ii), (a), (b), etc., in numbering components are used solely for the purpose of distinguishing one component from another 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 to exclude, unless there is a specific description contrary thereto. 
     In this specification, terms ‘left’ and ‘right’ are merely used to indicate directions in which certain components are illustrated in the drawings, and the present disclosure is not limited to the illustrated orientation and position of the components. 
       FIG. 2  is a cross-sectional view of a 3-way solenoid valve according to an embodiment of the present disclosure. In this specification, a longitudinal direction of the 3-way solenoid valve is defined as the Z axis, and a plane perpendicular to the longitudinal direction of the 3-way solenoid valve is defined as the X-Y plane. Among the directions shown in the drawing, an upper direction is defined as a ‘positive Z axis’ and a lower direction is defined as a ‘negative Z axis’. 
     Referring to  FIG. 2 , the 3-way solenoid valve  100  comprises all or part of a valve block  90 , a first operation assembly  110 , a second operation assembly  120 , a valve seat  70 , a first stopper  60   a , a second stopper  60   b , a second elastic unit  30   b  and a sealing part  50 . 
     The valve block  90  includes a valve chamber (not shown), a first fluid port A, a second fluid port B, and a third fluid port C. The first fluid port A, the second fluid port B, and the third fluid port C are in fluid communication with the valve chamber. 
     Here, the first fluid port A may be an inlet or outlet of fluid that may flow to a wheel cylinder W 1 , W 2 , W 3  or W 4  (refer to  FIG. 6 ) disposed on a wheel of a vehicle. The second fluid port B may be an inlet or an outlet of fluid that may be supplied from a brake device  200  (refer to  FIG. 6 ) according to an embodiment of the present disclosure. The third fluid port C may be an inlet or outlet of fluid that may flow in a direction toward the braking device  200  (refer to  FIG. 6 ). However, the first to third fluid ports A, B and C are not limited to the configuration and connection described above. Fluid flowing into or out of the first to third fluid ports A, B and C flows through the valve chamber in the valve block  90 . 
     The first operation assembly  110  includes all or part of a first coil  10   a , a first armature  20   a , a body  40 , and a first elastic unit  30   a.    
     The first armature  20   a  is configured to generate electromagnetic force when current is applied to the first coil  10   a , and a hollow portion is formed in the center. The body  40  is placed under the first armature  20   a , and at least a part of the first armature  20   a  passes through the inside of the body  40 . The first elastic unit  30   a  is placed between the body  40  and the first armature  20   a.    
     An orifice  22  is configured to protrude inwardly inside the hollow portion of the first armature  20   a . The orifice  22  may adjust a size of a flow path according to the degree of protrusion. The orifice  22  may protrude within a range in which the flow path is not blocked between the first armature  20   a  and the rod  21 . 
     The first coil  10   a  is disposed surrounding the outer circumferential surface of the first armature  20   a , and a sleeve may be disposed between the first coil  10   a  and the first armature  20   a.    
     A flow path connecting the first fluid port A and the second fluid port B is formed between the body  40  and the first armature  20   a  passing through the interior of the body  40 . That is, since the body  40  is fixed in the valve block  90 , the first elastic unit  30   a  pushes the first armature  20   a  in the positive Z-axis direction, so that an empty space is formed between the body  40  and the first armature  20   a.    
     When current is applied to the first coil  10   a , an electromagnetic force is generated in the first armature  20   a , so that the gap between the first armature  20   a  and the body  40  may be reduced. As the amount of current applied to the first coil  10   a  increases, a greater electromagnetic force is generated so that the first armature  20   a  and the body  40  come closer to each other. 
     The valve seat  70  is disposed to block the flow of fluid between the second fluid port B and the third fluid port C, and has a hollow portion formed in a center of the valve seat. A rod  21  is disposed through the hollow portion of the valve seat  70 , and a flow path is formed between the valve seat  70  and the rod  21 . 
     The second operation assembly  120  includes all or part of a second coil  10   b , a second armature  20   b , a fluid control unit  80  and a rod  21 . 
     The second coil  10   b  is disposed above the first coil  10   a . The second armature  20   b  is configured to generate an electromagnetic force when current is applied to the second coil  10   b . The fluid control unit  80  is disposed below the hollow portion of the valve seat  70  to control the amount of fluid flowing to the third fluid port C. The rod  21  is disposed so that at least a portion of the rod  21  passes through the first armature  20   a  and the valve seat  70 , and one end contacts the second armature  20   b  and the other end contacts the fluid control unit  80 . 
     The second coil  10   b  is disposed to surround the outer peripheral surface of the second armature  20   b , and a sleeve may be disposed between the second coil  10   b  and the second armature  20   b.    
     When current is applied to the second coil  10   b , an electromagnetic force is generated in the second armature  20   b , and the first armature  20   a  and the second armature  20   b  may be in close contact with each other by the electromagnetic force. 
     The rod  21  is affected by the movement of the second armature  20   b . When the second armature  20   b  moves downward due to the electromagnetic force formed in the second armature  20   b , the rod  21  also moves downward and pushes the fluid control unit  80 . A second flow path P 2 , which is a space between the sheets  70 , is formed. The second elastic unit  30   b  is disposed at the bottom of the fluid control unit  80 , and the fluid control unit  80  is in close contact with the bottom of the hollow portion of the valve seat  70  due to the elastic force of the second elastic unit  30   b.    
     The fluid control unit  80  may be formed in a spherical shape as shown in  FIG. 2 , but is not limited to the shape, and is arranged at the bottom of the hollow portion of the valve seat  70  to close the second flow path P 2 . 
     The first armature  20   a  may be independently driven by the first coil  10   a  and the second armature  20   b  may be independently driven by the second coil  10   b . That is, when current is applied to the first coil  10   a , an electromagnetic force may be formed only on the first armature  20   a , and when current is applied to the second coil  10   b , an electromagnetic force may be generated only on the second armature  20   b . The 3-way solenoid valve  100  according to an embodiment of the present disclosure supplies current to the first coil  10   a  to maintain a braking pressure of the wheel cylinder W 1 , W 2 , W 3 , or W 4 , increases the braking pressure of the wheel cylinder W 1 , W 2 , W 3 , or W 4  by supplying current to the first coil  10   a  and then releasing it, or supplies current to the first coil  10   a  and the second coil  10   b  to decrease the braking pressure of the wheel cylinder W 1 , W 2 , W 3 , or W 4 . 
     The sealing unit  50  is disposed inside the body  40 , and is formed in close contact with the first armature  20   a  by surrounding the outer circumferential surface. Fluid may flow between the outer circumferential surface of the first armature  20   a  and the sealing unit  50 . However, the sealing unit  50  is formed so that fluid flows only from the first fluid port A toward the second fluid port B, but that fluid does not flow from the second fluid port B to the first fluid port A. As shown in  FIG. 2 , the space of the sealing unit  50  is opened when the fluid flows from the first fluid port A to the second fluid port B, but does not flow in the opposite way, as the sealing unit  50  acts as a check valve. The sealing unit  50  is not limited to the shape as shown in  FIG. 2 . Having any shape such that fluid flows only in one-way, the sealing unit  50  according to an embodiment of the present disclosure is deemed in the range of the present invention. A first stopper  60   a  is disposed under the sealing part  50  to fix the sealing part  50  so as not to be separated. 
       FIG. 3  is a cross-sectional view illustrating a flow of fluid when no current is applied to the first coil and the second coil of the 3-way solenoid valve. 
     Hereinafter, in the description of  FIGS. 3 to 5 , the first fluid port A is defined as a port directly or indirectly connected to the wheel cylinder W 1 , W 2 , W 3  or W 4 , and the second fluid port B is defined as a port directly or indirectly connected to a pressurizing device (not shown) disposed in the brake device  200 , and the third fluid port C is defined as a port directly or indirectly connected to a low pressure accumulator (not shown) disposed in the brake device  200 . A first flow path P 1  refers to a space in which the fluid flowing space between the lower end of the first armature  20   a  and the upper end of the valve seat  70  is opened or closed. A second flow path P 2  refers to a space in which a space opened and closed through which the fluid flows between the lower end of the hollow portion of the valve seat  70  and the fluid control unit  80 . 
     Referring to  FIG. 3 , since current is not applied to both the first coil  10   a  and the second coil  10   b , the first flow path P 1  between the first armature  20   a  and the valve seat  70  is opened, and thereby fluid between the first fluid port A and the second fluid port B flows through the hollow portion of the first armature  20   a  and the first flow path P 1 . This will be described in detail below. 
     When no current is applied to both the first coil  10   a  and the second coil  10   b , electromagnetic force is not formed in the first armature  20   a  and the second armature  20   b . Accordingly, an attractive force due to electromagnetic force is not formed between the first armature  20   a , the second armature  20   b  and the body  40 . A gap is formed between the first armature  20   a  and the body  40  due to the elastic force of the first elastic unit  30   a . That is, the first armature  20   a  is moved in the positive Z-axis direction by the first elastic portion  30   a  to open the first flow path P 1 . Since the lower end of the hollow portion of the valve seat  70  is blocked by the fluid control unit  80 , the second flow path P 2  is not opened. 
     In general, in a brake system for vehicle, an inlet valve is normal open type in which a flow path is opened when no current is applied, and an outlet valve is normal close type in which a flow path is closed when no current is applied. 
     In the 3-way solenoid valve  100  according to an embodiment of the present disclosure, when no current is applied, the first flow path P 1  disposed between the first fluid port A and the second fluid port B is opened, and the second flow path P 2  disposed between the first fluid port A and the third fluid port C is closed. Accordingly, the 3-way solenoid valve  100  according to an embodiment of the present disclosure has all the features of the conventional inlet valve of normal open type and the conventional outlet valve of normal close type. 
     In addition, the sealing unit  50  is formed so that fluid flows only in the direction from the first fluid port A to the second fluid port, which replaces the role of a conventional check valve disposed in a conventional the inlet valve. 
     The process of  FIG. 3  corresponds to a case where the inlet valve is opened and the outlet valve is closed in a brake system for vehicle of prior art. 
       FIG. 4  is a cross-sectional view illustrating a flow of fluid when current is applied to the first coil of the 3-way solenoid valve. 
     Referring to  FIG. 4 , since current is applied to the first coil  10   a , the first armature  20   a  moves toward the body  40  due to the electromagnetic force formed by the first coil  10   a  so that the amount of fluid flowing between the first fluid port A and the second fluid port B decreases or the flow path between the first fluid port A and the second fluid port B is blocked. This will be described in detail below. 
     When current is supplied to the first coil  10   a , an electromagnetic force is formed in the first armature  20   a , and an attractive force is applied between the first armature  20   a  and the body  40  due to the electromagnetic force. That is, the first armature  20   a  moves in the negative Z-axis direction. When the first armature  20   a  moves in the negative Z-axis direction, the size of the first flow path P 1  decreases, and this size may be further reduced as the amount of current applied to the first coil  10   a  increases. The first flow path P 1  is closed when more current is supplied to the first coil  10   a  until the lower end of the first armature  20   a  contacts the valve seat  70 , and as a result, fluid can no longer flow from the second fluid port B to the first fluid port A. The second flow path P 2  is also closed by the fluid control unit  80 . 
     When the first flow path P 1  and the second flow path P 2  are closed, the hydraulic pressure of the pressurizing device (not shown) in the brake device  200  is generally higher than that of the wheel cylinder W 1 , W 2 , W 3  or W 4 . Therefore, fluid does not flow through the sealing unit  50 . In case where the hydraulic pressure of the pressurizing device (not shown) in the brake device  200  decreases sharply, such as when driver abruptly release a depression of a brake pedal, fluid flows from the first fluid port A to the second fluid port B by passing through the sealing unit  50  due to the difference in hydraulic pressure. That is, the sealing unit  50  can prevent a wheel-lock by rapidly reducing the hydraulic pressure in the wheel cylinder W 1 , W 2 , W 3  or W 4  in a situation in which the hydraulic pressure in the brake device  200  decreases rapidly. 
     The process of  FIG. 4  corresponds to a case where both the inlet valve and the outlet valve are closed in the brake system for vehicle of the prior art. When maintaining the braking pressure applied to the wheel cylinder W 1 , W 2 , W 3  or W 4 , the process of  FIG. 4  may be applied. 
       FIG. 5  is a cross-sectional view illustrating a flow of fluid when current is applied to the first coil and the second coil of the 3-way solenoid valve. 
     Referring to  FIG. 5 , when current is applied to the first coil  10   a  and the second coil  10   b , the first armature  20   a , the second armature  20   b , and the body  40  are in close contact with each other due to electromagnetic force. The second flow path P 2  between the fluid control unit  80  and the valve seat  70  is opened so that fluid may flow between the first fluid port A and the third fluid port C. This will be described in detail below. 
     As current is applied to the first coil  10   a , the first armature  20   a  moves downward to block the first flow path P 1  as described in  FIG. 4 . The current amount applied to the first coil  10   a  should be sufficient to block the first flow path P 1  by moving the first armature  20   a  as close as possible to the body unit  40  in consideration of the elastic force of the first elastic unit  30   a . When current is applied to the second coil  10   b , an electromagnetic force is generated in the second armature  20   b , and the second armature  20   b  also moves downward in order to come into close contact with the first armature  20   a  that moved downward. 
     As the second armature  20   b  moves downward, it pushes the rod  21  in the negative Z-axis direction. The pushed rod  21  pushes the fluid control unit  80  in contact with one end of the rod  21  to thereby open the second flow path P 2 . Therefore, fluid may flow between the first fluid port A and the third fluid port C. The process of  FIG. 5  may correspond to the case where the inlet valve is closed and the outlet valve is opened in the brake system for vehicle of prior art. When reducing the braking pressure supplied to the wheel cylinder W 1 , W 2 , W 3  or W 4 , the process of  FIG. 5  may be applied. 
       FIG. 6  is a block diagram of a brake system for vehicle including the 3-way solenoid valve according to an embodiment of the present disclosure. 
     Referring to  FIG. 6 , a brake system for vehicle  1000  according to an embodiment of the present disclosure includes a brake device  200 , one or more 3-way solenoid valves  100 , and one or more wheel cylinders W 1 , W 2 , W 3  and W 4 . Here, the 3-way solenoid valve  100  is same as described in  FIGS. 2 to 5 . 
     Each of the wheel cylinders W 1 , W 2 , W 3  and W 4  are disposed on each wheel of the vehicle to apply braking pressure to each wheel using hydraulic pressure. When hydraulic pressure is supplied to the wheel cylinders W 1 , W 2 , W 3 , and W 4 , a brake pad disposed on the wheel of the vehicle contacts a wheel disk to generate a friction force, thereby generating braking force. 
     The brake device  200  is arranged to supply hydraulic pressure to the wheel cylinders W 1 , W 2 , W 3 , and W 4  by using a foot force applied to a brake pedal or driving a hydraulic pump. Here, the brake device  200  can supply hydraulic pressure by amplifying foot force applied as the driver depresses a brake pedal, or can supply hydraulic pressure by operating a hydraulic pump as much as the amount of a driver&#39;s pedal depression. 
     Among the configurations of the 3-way solenoid valve  100  described in  FIGS. 2 to 5 , the orifice  22  protruding and disposed inside the hollow portion of the first armature  20   a  may have a different effective area between the first armature  20   a  and the rod  21  according to the degree of protrusion. For example, in case of a front wheel that requires a relatively large amount of fluid, it is possible to adjust the amount of fluid supplied to each wheel by decreasing the protrusion height of the orifice  22  of the 3-way solenoid valve disposed on the front wheels and increasing the protrusion height of the orifice  22  of the 3-way solenoid valve disposed on the rear wheels. 
     The block diagram of the vehicle braking system shown in  FIG. 6  is exemplary, and is not limited to the configuration and arrangement shown in  FIG. 6 . 
     As described above, according to some embodiments of the present disclosure, the brake system for vehicle including the 3-way solenoid valves minimizes the number of valves deployed in the brake system for vehicle by using three-way fluid port and by using sealing part that acts as a check valve, so that manufacturing cost is reduced and the weight and size of the brake system for vehicle is reduced. 
     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 that the scope of the claimed invention is not to be limited by the above descriptions but by the claims and equivalents thereof.