Patent Publication Number: US-2022215995-A1

Title: Coil assembly for breaking vehicle and brake apparatus having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from and the benefit of Korean Patent Application No. 10-2021-0000214, filed on Jan. 4, 2021, which is hereby incorporated by reference for all purposes as if set forth herein. 
     TECHNICAL FIELD 
     Field 
     Exemplary embodiments relate to a coil assembly for vehicle braking and a brake apparatus having the same. More particularly, the present disclosure relates to a coil assembly for vehicle braking and a brake apparatus having the same for use in vehicle ABS (Anti-lock Brake System) and similar systems. 
     Discussion of the Background 
     The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. 
     If a vehicle is braked only by a driver&#39;s manual operation when a vehicle slip occurs, the driver may apply the brake pedal and at the same time hold the steering wheel to prevent the wheels from rotating. However, such manual braking cannot usually achieve an optimal braking reflecting a driving condition of the vehicle and the road surface conditions, and therefore, the risk of an accident rises. 
     Accordingly, various technologies and methods for automatically controlling braking pressure have been adopted to overcome such limitations of a simple manual braking and to improve vehicle stability when braking a vehicle. For example, an ABS (Anti-lock Brake System) is configured to prevent the vehicle from slipping by automatically and quickly adjusting the braking pressure applied to the wheels according to the slip ratio calculated from the driving state of the vehicle. 
     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 
     According to at least one embodiment, the exemplary embodiments of the present disclosure provides a coil assembly for vehicle braking, including a hollow type bobbin configured to allow a coil to be wound along an outer circumferential surface thereof, and having at least one engagement protrusion formed on an upper surface and/or a lower surface; a plurality of lead pins coupled with the bobbin to supply current to the coil; a plurality of pin assembly units formed on both side ends of the bobbin to fix the lead pins and connect the lead pins to the coil; and a hollow type case configured to surround at least a portion of the bobbin, and formed to be bent in the upper and lower portions in a first direction to thereby be attached to the upper and lower surfaces of the bobbin, and including at least one engagement hole to be engaged with the engagement protrusion and a step difference formed on both sides to narrow the width of the surface to be engaged with the engagement protrusion. 
     According to another embodiment, the present disclosure provides a brake apparatus, including a coil assembly for vehicle braking including a hollow type bobbin configured to allow a coil to be wound along an outer circumferential surface thereof, and having at least one engagement protrusion formed on an upper surface and/or a lower surface; a plurality of lead pins coupled with the bobbin to supply current to the coil; a plurality of pin assembly units formed on both side ends of the bobbin to fix the lead pins and connect the lead pins to the coil; and a hollow type case configured to surround at least a portion of the bobbin, and formed to be bent in the upper and lower portions in a first direction to thereby be attached to the upper and lower surfaces of the bobbin, and including at least one engagement hole to be engaged with the engagement protrusion and a step difference formed on both sides to narrow the width of the surface to be engaged with the engagement protrusion; a first housing including a printed circuit board that may be coupled with the lead pins by use of press-fitting or soldering, and configured to accommodate the coil assembly for vehicle braking; and a second housing includes a valve assembly accommodated in the bobbin and configured to control the opening and closing of an oil flow path, and is coupled with the first housing so that the outer surface may contact the case. 
     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 an exploded perspective view illustrating a coil assembly for vehicle braking. 
         FIG. 2  is a cross-sectional view illustrating a braking device including a coil assembly for vehicle braking taken along the Y axis. 
         FIG. 3  is an exploded perspective view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
         FIG. 4  is a front view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
         FIG. 5  is a plane view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
         FIG. 6  is a side view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are illustrated. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals in the drawings denote like elements. 
     At least one embodiment of the present disclosure seeks to address the above issues and to provide a coil assembly for vehicle braking and a brake apparatus having the same that reduces the overall manufacturing process costs while the coil assembly for vehicle braking has a 3-axis degree of freedom. 
     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 illustrated 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 code such as first, second, i), ii), (a), (b), etc., in numbering components are used solely for the purpose of 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 an explicit description contrary thereto. 
     Terms such as “upper,” “lower,” “top,” “bottom,” “side,” and so forth may be used for identification of certain sides of a given figure but are not meant to be limiting in that the device or apparatus must always be positioned in a given direction. For example, what is labeled “upper” in one figured may be a “lower” portion or a “side” portion in another figure or in use of the actual device of the device or apparatus. 
     In addition, control of a braking pressure may be achieved by installing various solenoid valves on a hydraulic circuit formed between a wheel cylinder that holds and restrains a disk wheel and a master cylinder that generates hydraulic pressure. Herein, the control of the solenoid valves is performed by an ECU (Electronic Control Unit), and the braking pressure can be adjusted by performing control of the opening and closing of the solenoid valves by the ECU. The solenoid valves generally consist of a coil assembly and a valve assembly combined. 
       FIG. 1  is an exploded perspective view of a coil assembly for vehicle braking. 
       FIG. 2  is a cross-sectional view of a braking device including a coil assembly for vehicle braking taken along the Y axis. 
     Referring to  FIG. 1 , a coil assembly for vehicle braking  10  includes a bobbin  100 , a plurality of lead pins  140 , an upper case  160 , and a lower case  180 . 
     A coil  120  is wound around the bobbin  100  to produce an electromagnetic field when current is applied to the coil  120 , and the lead pins  140  are for supplying current to the coil  120 . The upper case  160  and the lower case  180  protect the bobbin  100 , release heat generated from the coil  120 , and transmit an electromagnetic field produced in the coil to the valve assembly ( 200  in  FIG. 2 ). 
     Referring to  FIG. 2 , a braking device including a coil assembly for vehicle braking  10  includes a valve assembly  200  capable of opening and closing an internal flow path by using an electromagnetic field produced in the coil  120  and a pump housing  220  which may contact the lower case  180 . 
     Because current flows through the coil  120 , it is desired to dissipate heat generated from the coil  120 . Therefore, it is desirable to have a degree of freedom in the Z-axis direction so that the lower case  180  surrounding the outer circumferential surface of the coil  120  can be in close contact with the outer surface of the pump housing  220 . 
     In addition, when the pump housing  220  and the ECU housing (not illustrated) are assembled, the height of the coil  120  may become different from that of a normal case due to variations between products. Because such a height tolerance of the coil  120  is the main cause of an ECU performance deviation and noise, it is desirable to minimize the tolerance. When the coil assembly for vehicle braking  10  has a degree of freedom in the Z-axis direction, the above tolerance can be compensated. 
     Meanwhile, in order to prevent interference caused by assembling the coil assembly for vehicle braking  10  and the valve assembly  200 , it is desirable that the coil assembly for vehicle braking  10  be configured to have degrees of freedom in the X and Y axes. 
     However, in case that the outer circumferential surface of the coil  120  is surrounded by the lower case  180  as with the coil assembly for vehicle braking  10 , this structure should be manufactured by using a deep drawing method. This increases the material cost and process cost for manufacturing the coil assembly for vehicle braking  10 . Therefore, it is desired to configure the coil assembly to have X-axis, Y-axis and Z-axis degrees of freedom without using such a deep drawing method. 
       FIG. 3  is an exploded perspective view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
       FIG. 4  is a front view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
       FIG. 5  is a plane view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
       FIG. 6  is a side view illustrating a coil assembly for vehicle braking according to an embodiment of the present disclosure. 
     Referring to  FIGS. 3 to 6 , the coil assembly  30  for vehicle braking according to at least one embodiment of the present disclosure includes all or part of a bobbin  300 , a case  340 , a plurality of lead pins  360  and a pin assembly unit  380 . 
     The bobbin  300  is configured to allow a coil  320  to be wound along its outer circumferential surface. Because the bobbin  300  is of a hollow type, a bobbin central hole  305  is formed in a center of the bobbin. A valve assembly (not illustrated) may be assembled in the bobbin central hole  305 , and the valve assembly is configured to control the opening and closing of an oil flow path by using a magnetic field generated by a current flowing through the coil  320 . 
     The bobbin  300  may be injection-molded using a plastic material, and at least one engagement protrusion  302  may be formed on an upper surface  301  and/or a lower surface  303  of the bobbin  300 . In  FIG. 3 , it is illustrated that two engagement protrusions  302  are formed on the upper surface  301  of the bobbin  300 . The at least one engagement protrusion  302 , however, is not limited to the example configuration illustrated in  FIG. 3 . Specifically, the at least one engagement protrusion  302  may also be formed on the lower surface  303  of the bobbin  300 , and the number of engagement protrusions  302  is not limited to two. 
     The case  340  is configured to surround at least a portion of the bobbin  300 . The case  340  is formed to be bent in an upper portion  341  and a lower portion  343  thereof in a first direction to thereby be attached to the upper surface  301  and lower surface  303  of the bobbin  300 . Here, the first direction may mean, for example, the Y-axis direction in  FIG. 3 . Accordingly, as illustrated in  FIG. 6 , when viewed from the side, the case  340  may have a “C” shape. However, the direction in which the upper portion  341  and lower portion  343  of the case  340  are bent is not necessarily the Y-axis direction in  FIG. 3 , and the bending direction may be changed depending on the position of the at least one coupling protrusion  302  and the position of the pin assembly unit  380  to be described later. 
     Meanwhile, the valve assembly is assembled in the bobbin central hole  305  and configured to control the opening and closing of an oil flow path. Therefore the case central hole  345  may be formed at a position corresponding to the bobbin central hole  305  on the bent surface of the case  340 . Herein, it is desirable that the center of the case central hole  345  and that of the bobbin central hole  305  coincide with each other. 
     The case  340  may include at least one engagement hole  342  to engage with the at least one engagement protrusion  302 . Here, the at least one engagement hole  342  may include one or multiple, and is desirably formed to correspond to the number and position of the at least one engagement protrusions  302 . 
     As the at least one engagement protrusion  302  and the at least one engagement hole  342  are engaged, the case  340  is attached to the upper surface  301  and the lower surface  303  of the bobbin  300  and may be firmly engaged without an additional fixing component. As the case  340  is attached to and engaged to the bobbin  300 , heat generated from the coil  320  can be dissipated via the case  340 . 
     In the manufacturing of a previous case, the case has a cylindrical shape in order to correspond to the shape of the bobbin  300 , and therefore a deep drawing method should be applied. In such a case, even after the application of the deep drawing method, additional processes such as a cleaning process for removing drawing oil and a zinc plating for improving erosion resistance are required, and therefore the overall process cost increases. 
     However, in the coil assembly  30  according to an embodiment of the present disclosure, the case  340  surrounding the bobbin  300  need not be configured in a cylindrical shape that corresponds to the shape of the bobbin  300 . Therefore, there is no need to use a deep drawing method when manufacturing the case  340 , and it may be manufactured by using, for example, a pre-plated steel plate, thereby reducing the overall process cost. 
     The lead pins  360  are coupled with the bobbin  300  to supply current to the coil  320 . The lead pins  360  may be include a plurality, for example, two. One end of the lead pins  360  may be connected to a printed circuit board (not illustrated), and the other end of the lead pins  360  may be connected to the coil  320 . In addition, for the sake of structural stability, it is desirable that the lead pins  360  are configured to be symmetrical to each other with respect to the first direction that passes along the center of the bobbin  300 . 
     An upper surface  301  or a bottom surface  303  of the bobbin  300  may have multiple side ends on which to mount the pin assembly units  380 . The pin assembly units  380  may be formed at two side ends of the bobbin  300  and are configured to fix the lead pins  360  and connect the lead pins  360  to the coil  320 . The pin assembly units  380  may be configured in the plural, and the number of the pin assembly units  380  is preferably the same as the number of the lead pins  360 . In this case, the lead pins  360  may be fixed to the pin assembly units  380  and may be connected to the bobbin  300  and coil  320  by using the pin assembly units  380 . 
     In addition, in order to fix the lead pins  360 , the pin assembly units  380  are configured to be engaged with the lead pins  360  by inserting the lead pins  360  into the pin assembly units  380 . 
     Meanwhile, when the lead pins  360  are configured to be symmetrical to each other with respect to the first direction that passes along the center of the bobbin  300 , it is desirable that the pin assembly units  380  are also configured to be symmetrical to each other with respect to the first direction that passes along the center of the bobbin  300 . Herewith, when the pin assembly units  380  are formed on both side ends of the bobbin  300 , an interference may occur between the case  340  and the pin assembly units  380  in a process in which the bobbin  300  and the case  340  are engaged. 
     Referring to  FIG. 5 , for avoidance of the above interference, the case  340  may include a step difference  500  formed on both sides of the case  340  to narrow the width of the upper portion  341  or lower portion  343  to be engaged with the engagement protrusion  302 . Due to the step difference  500  in the case  340 , a sufficient space can be secured for the pin assembly units  380 . In addition, interference between the case  340  and the pin assembly units  380  may be prevented while the bobbin  300  and the case  340  are combined. 
     Meanwhile, each of the lead pins  360  may include a fixing portion  366 , an elastic portion  364 , and a coil connecting portion  362 . 
     The fixing portion  366  is formed to be elongated in a second direction and configured to be coupled with the printed circuit board. Here, the second direction refers to the Z-axis direction in  FIG. 3 . The second direction is a height direction of the bobbin  300 , and the first direction and the second direction are perpendicular to each other. However, the second direction need not be configured in a direction perpendicular to the first direction. 
     The fixing portion  366  includes a protruding portion  368  protruding from the fixing portion  366 . This is configured to prevent the fixing portion  366  from being separated from the printed circuit board if the fixing portion  366  is press-fitted or soldered to the printed circuit board. Meanwhile, referring to  FIGS. 3 to 6 , the protruding portion  368  is illustrated to be formed at a point corresponding to approximately a middle of the fixing portion  366 . As long as the protruding portion  368  protrudes from the fixing portion  366 , however, the position of the protruding portion  368  is not limited thereto. 
     The elastic portion  364  is formed to extend in a direction perpendicular to the second direction from the fixing portion  366 . The elastic portion  364  may be configured to be elastically deformable by an external force. 
     Referring to  FIGS. 3 to 6 , the coil assembly  30  is configured to be movable according to the deformation direction of the elastic portion  364 . For example, when a force is applied in the −Z axis direction to the elastic portion  364 , the elastic portion  364  is deformed in the −Z axis direction, so that the coil assembly  30  can accordingly move in the −Z axis direction. 
     Therefore, in the process of assembling a pump housing (not illustrated) and an ECU (Electronic Control Unit) housing (not illustrated), a problematic occurrence of the height tolerance of the coil  320  may be prevented. In addition, it becomes easier to dissipate heat generated from the coil  320  because the case  340  is in close contact with the pump housing. 
     In addition, referring to  FIGS. 5 and 6 , the elastic portion  364  is configured to be deformable in the second direction as well as the first direction, for example the Y-axis direction when the second direction is the height direction of the bobbin  300 , that is, the Z-axis direction. Further, the elastic portion  364  can also be deformed in a third direction perpendicular to the first and second directions, for example, the X-axis direction. When a force in the X-axis and/or Y-axis direction is applied to the elastic portion  364 , the elastic portion  364  is deformed in the X-axis and/or Y-axis direction, so that the coil assembly  30  can be moved in the X-axis and/or Y-axis direction. 
     Therefore, the above configuration helps prevent an interference between the valve assembly and the bobbin  300  when assembling the valve assembly in the bobbin central hole  305 . 
     The coil connecting portion  362  extends in the second direction from the elastic portion  364  and is configured to be coupled with the pin assembly units  380 . The coil connecting portions  362  are coupled with the pin assembly units  380  by inserting the coil connecting portion  362  into the pin assembly units  380 , and are connected to the coil  320  passing through the pin assembly units  380 . 
     For example, the coil  320  may be connected to the coil connecting portion  362  while being wound around the coil connecting portion  362 . In order to fix the coil  320  to the coil connecting portion  362 , the coil  320  may be bonded with the coil connecting portion  362  by using a resistance welding. However, the bonding method of the coil  320  is not necessarily limited to the resistance welding, and, for example, a soldering method may be used. 
     According to an embodiment of the present disclosure, the lead pins  360  include the above configuration, and the elastic portion  364  is deformable in the X-axis, Y-axis, and Z-axis, so that a 3-axis degree of the freedom of the coil assembly  30  for vehicle braking can be secured. 
     In order to expand a movable range of the coil assembly  30 , it is desirable that the length of the elastic portion  364  is sufficiently secured. Therefore, the pin assembly units  380  may be formed at both side ends of the bobbin  300  and configured to be symmetrical to each other with respect to the first direction that passes along the center of the bobbin  300 . Further, the elastic portion  364  may be configured to extend in a diagonal direction with respect to the first direction from the fixing portion  366  as illustrated in  FIG. 5 . 
     Because the pin assembly units  380  and the elastic portion  364  are configured as described above, the length of the elastic portion  364  may be sufficiently secured. Specifically, it is desirable that the pin assembly units  380  are formed on both side ends of the bobbin  300  and the elastic portion  364  is configured to extend in the diagonal direction with respect to the first direction in order to secure structural stability and a sufficient length of the elastic portion  364 , in a state that the coupling position of the fixing portion  366  and the printed circuit board is determined. 
     Meanwhile, referring to  FIG. 7 , according to an embodiment of the present disclosure, the braking apparatus may include the coil assembly  30 , a first housing  700  and a second housing (not illustrated). 
     The description of the coil assembly  30  is the same as described above, and therefore it will be omitted hereinafter. 
     The first housing  700  includes the printed circuit board  720  that can be coupled with the lead pins  360  by use of press-fitting or soldering, and is configured to accommodate the coil assembly  30  therein. In  FIG. 7 , it is shown that the coil assembly  30  does not include the case  340 , however, the coil assembly  30  may include the case  340 . In this case, the shape of the portion of the first housing  700  accommodating the coil assembly  30  can be changed. 
     Each of the lead pins  360  may include the protruding portion  368  protruding from each of the lead pins  360 . Each of the lead pins  360  may be coupled with the first housing  700  using the protruding portion  368 . Because the protruding portion  368  is coupled with the first housing, the lead pins  360  cannot be easily separated from the printed circuit board  720 . A detailed description of the protruding portion  368  has been described above, and therefore it will be omitted hereinafter. 
     The second housing includes the valve assembly accommodated in the bobbin  300  and configured to control the opening and closing of the oil flow path. The second housing is coupled with the first housing so that the outer surface may contact the case  340 . 
     The braking apparatus including the above configuration is configured to automatically and electronically control the opening and closing of the oil flow path, and therefore an anti-lock brake system (ABS) of the vehicle becomes implementable. In addition, because there is no need to apply the deep drawing method when manufacturing the coil assembly  30 , manufacturing process costs may be reduced compared to that of previous braking apparatuses. 
     As described above, according to the exemplary embodiment of the present disclosure, the coil assembly  30  for vehicle braking has a three-axis degree of freedom while reducing the overall manufacturing process cost. 
     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.