Patent Publication Number: US-2023146380-A1

Title: Vehicle brake apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 USC § 119(a) to Korean Patent Applications No. 10-2021-0151159, filed on Nov. 5, 2021, the entire disclosure of which is incorporated herein by reference for all purposes. 
     TECHNICAL FIELD 
     Exemplary embodiments of the present disclosure relate to a vehicle brake apparatus, and more particularly, to a vehicle brake apparatus, which can have a reduced weight and reduced overall size in an automotive electronic component thereof, compared to the related art, in a case where a load sensor is applied thereto. 
     BACKGROUND 
     Generally, an electro-mechanical brake (EMB) is a system that generates braking force in a manner that converts a driver&#39;s stepping force on a brake pedal into an electrical signal and operates a motor mounted on a caliper, unlike a hydraulic brake system of the related art. Motive power of the motor is transmitted to a piston unit by a driveline unit, and then the piston unit is operated. Thus, a brake pad presses a brake disc in a manner that is brought into contact with the brake disc. In this case, a load sensor is connected to the piston unit for being combined therewith. 
     However, as the size of the piston unit varies with vehicle types, the size of the load sensor increases rapidly. Thus, there occurs a problem in that the weight of the EMB is increased and the overall size of the automotive electronic component becomes bigger. Accordingly, there is a need to solve the above problem. 
     The background technology of the disclosure is disclosed in Korean Patent No. 10-0456779 registered on Nov. 2, 2004, and entitled “Vehicle Brake Apparatus”. 
     SUMMARY 
     Various embodiments are directed to a vehicle brake apparatus, which can have a reduced weight and reduced overall size in an automotive electronic component thereof, compared to the related art, in a case where a load sensor is applied thereto. 
     In an embodiment, to achieve the objects, a vehicle brake apparatus includes: a motor unit configured to generate motive power with received external electrical power; a driveline unit provided with a reduction gear unit that is rotated by drive of the motor unit and reduces the motive power of the motor unit and a bearing that supports rotation of the reduction gear unit; a cylinder unit configured to press a brake pad with the motive power received from the driveline unit; a load sensing unit configured to sense a load produced from axial force of the reduction gear unit; and a housing unit connected to the motor unit and having the driveline unit and the load sensing unit installed therein. 
     In an embodiment, the vehicle brake apparatus may include a control unit configured to receive sensing information from the load sensing unit and output braking force produced between the brake pad and a brake disc based on the sensing information. 
     In an embodiment, the reduction gear unit may include: a first reduction gear engaged with a driving gear of the motor unit for being combined therewith and rotated with rotational force received from the driving gear; a second reduction gear connected to the first reduction gear and configured to receive rotational force from the first reduction gear; a third reduction gear engaged with the second reduction gear for being combined therewith and configured to receive rotational force from the second reduction gear; a fourth reduction gear connected to the third reduction gear and configured to receive rotational force from the third reduction gear; and a fifth reduction gear connected to the cylinder unit and supported by the bearing for being rotated, wherein the load sensing unit senses the load produced from axial force of the fifth reduction gear. 
     In an embodiment, the fifth reduction gear may include: a shaft connected to the cylinder unit, having the bearing mounted thereon, and brought into contact with the load sensing unit; and a fifth reduction body gear connected to the shaft and engaged with the fourth reduction gear for being combined therewith. 
     In an embodiment, the load sensing unit may include a load cell, is arranged in parallel to the bearing, and is brought into contact with the shaft in an axial direction. 
     In an embodiment, the load sensing unit may include: an elastic member configured to support the bearing elastically; a magnet installed in the bearing and having a position varied by elastic force of the elastic member; and a position sensor installed in the housing unit, and configured to determine a position of the magnet by sensing a magnetic field of the magnet, and to sense a load according to the axial force of the fifth reduction gear based on the position of the magnet. 
     In an embodiment, the bearing comprises: a bearing inner ring configured to surround the shaft of the fifth reduction gear; a bearing outer ring configured to surround an outer side of the bearing inner ring, having the magnet installed therein, and supported elastically by the elastic member; and a plurality of balls arranged between the bearing inner ring and the bearing outer ring. 
     In an embodiment, the cylinder unit comprises: a screw bar connected to the fifth reduction gear and pivoted with rotational force received from the fifth reduction gear; a spindle configured to surround an outer side of the screw bar and moved toward the brake pad while being rotated by rotational force of the screw bar; and a cylinder configured to surround the spindle and press the brake pad by being moved in conjunction with the spindle. 
     In the vehicle brake apparatus according to the present disclosure, the load sensing unit is arranged on the reduction gear unit in such a manner as to sense the load produced from the axial force of the reduction gear unit. Therefore, the vehicle brake apparatus according to the present disclosure provides the effect of reducing the weight of the load sensing unit compared to the related art that applies the load sensing unit to the cylinder. 
     In addition, as the weight of the load sensing unit is reduced, the overall weight of the vehicle brake apparatus can be reduced, and thus the automotive electronic component thereof can decrease, resulting in cost reduction in parts of the apparatus. Furthermore, even for various vehicle types, the weight change of the load sensing part is less than in the related art, resulting in easier layout work in the design. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a vehicle brake apparatus according to an embodiment of the present disclosure. 
         FIG.  2    is a cross-sectional view taken along line A-A′ of  FIG.  1   . 
         FIG.  3    is a cross-sectional view taken along line B-B′ of  FIG.  1   . 
         FIG.  4    is a view of the vehicle brake apparatus according to the embodiment of the present disclosure when viewed from another direction. 
         FIG.  5    is a partially exploded perspective view of  FIG.  4   . 
         FIG.  6    is an enlarged view of a portion A of  FIG.  5   . 
         FIG.  7    is an exploded perspective view of  FIG.  6   . 
         FIG.  8    is a view illustrating a vehicle brake apparatus according to another embodiment of the present disclosure. 
         FIG.  9    is a cross-sectional view taken along line A-A′ of  FIG.  8   . 
         FIG.  10    is a cross-sectional view taken along line B-B′ of  FIG.  8   . 
         FIG.  11    is a view of the vehicle brake apparatus according to another embodiment of the present disclosure when viewed from another direction. 
         FIG.  12    is a partially exploded perspective view of  FIG.  11   . 
         FIG.  13    is an enlarged view of a portion B of  FIG.  12   . 
         FIG.  14    is an enlarged view of a portion C of  FIG.  12   . 
         FIG.  15    is an exploded perspective view of main components of  FIG.  12   . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a vehicle brake apparatus will be described with reference to the accompanying drawings through various exemplary embodiments. 
     In such a process, for clarity and convenience in description, thicknesses of lines, sizes of constituent elements, and the like may be illustrated in an exaggerated manner in the drawings. Further, terms to be described hereinafter have been defined in consideration of functions in the disclosure, and may differ depending on a user or an operator&#39;s intention, or practice. Therefore, definitions of these terms should be stated in light of details disclosed throughout the present specification. 
       FIG.  1    is a view illustrating a vehicle brake apparatus according to an embodiment of the present disclosure,  FIG.  2    is a cross-sectional view taken along the line A-A′ of  FIG.  1   ,  FIG.  3    is a cross-sectional view taken along the line B-B′ of  FIG.  1   ,  FIG.  4    is a view illustrating the vehicle brake apparatus according to the embodiment of the present disclosure when viewed from another direction,  FIG.  5    is a partially exploded perspective view of  FIG.  4   ,  FIG.  6    is an enlarged view of a portion A of  FIG.  5   , and  FIG.  7    is an exploded perspective view of  FIG.  6   . 
     Referring to  FIGS.  1  to  7   , a vehicle brake apparatus  1  according to the embodiment of the present disclosure includes a motor unit  100 , a driveline unit  200 , a cylinder unit  300 , a load sensing unit  400 , and a housing unit  500 . The motor unit  100  generates motive power with electrical power supplied thereto. In this case, the motive power generated from the motor unit  100  is transmitted to the driveline unit  200 . 
     The motor unit  100  includes a motor main body  110 , a motor shaft part  120 , and a driving gear  130 . The motive power is generated from the motor main body  110 . The motor shaft part  120  is connected to the motor main body  110  and rotated by the motive power of the motor main body  110 . The driving gear  130  is installed on the motor shaft part  120  and rotated in conjunction with the motor shaft part  120 . 
     The driveline unit  200  is provided with a reduction gear unit  210  and a bearing  220 . The reduction gear unit  210  is rotated by the drive of the motor unit  100  and reduces the motive power of the motor unit  100 . 
     The bearing  220  supports the rotation of the reduction gear unit  210 . In this case, the bearing  220  supports the rotation of a fifth reduction gear  215  of the reduction gear unit  210 . 
     The cylinder unit  300  presses a brake pad  10  with the motive power received from the driveline unit  200 . The cylinder unit  300  is connected to the reduction gear unit  210  of the driveline unit  200  but receives the reduced motive power from the reduction gear unit  210 . 
     The cylinder unit  300  is installed in a caliper body  30  and includes a screw bar  310 , a spindle  320 , and a cylinder  330 . The screw bar  310  is connected to the fifth reduction gear  215  of the reduction gear unit  210  and pivots with a rotational force received from the fifth reduction gear  215 . The screw bar  310  is inserted into the spindle  320  described below in a rod shape and is provided with a male screw thread (not illustrated) formed on the outer side thereof. 
     The spindle  320  surrounds the screw bar  310  and is moved toward the brake pad  10  in a manner that is rotated by the rotational force of the screw bar  310 . A female screw thread (not illustrated) is formed on the inner side of the spindle  320 , and the female screw thread is engaged with the male screw thread of the screw bar  310  for being combined therewith. 
     Specifically, in a case where the screw bar  310  is rotated in a predetermined direction, the spindle  320  is moved toward the brake pad  10  in a manner that converts a rotary motion of the screw bar  310  into a straight line motion. Conversely, in a case where the screw bar  310  is rotated in an opposite direction from the predetermined direction, the spindle  320  is moved toward the opposite side of the brake pad  10 . 
     The cylinder  330  surrounds the spindle  320  and presses the brake pad  10  in a manner that is moved in conjunction with the spindle  320 . The cylinder  330  is, in a shape of surrounding the spindle  320 , moved with the spindle  320  toward the brake pad  10  or toward the opposite side of the brake pad  10  by the pressurization of the spindle  320 . 
     The load sensing unit  400  senses a load produced from an axial force of the reduction gear unit  210 . The load sensing unit  400  may be mounted on the housing unit  500  in such a manner as to be in contact with the reduction gear unit  210  in an axial direction. In this case, the axial force is proportional to the braking force produced between the brake pad  10  and a brake disc  20 . 
     The housing unit  500  is connected to the motor unit  100 , and houses the driveline unit  200  and the load sensing unit  400 . The housing unit  500  includes a first housing  510 , a second housing  520 , and a third housing  530 . The first housing  510  is combined with the motor unit  100 . The second housing  520  is combined with the first housing  510 , and the driveline unit  200  and the load sensing unit  400  are installed therein. The third housing  530  is combined with the first housing  510 . 
     A control unit  600  receives sensing information from the load sensing unit  400  and outputs the braking force produced between the brake pad  10  and the brake disc  20  based on the sensing information. Based on the sensing information received from the load sensing unit  400 , the control unit  600  may output and show braking force on a display (not illustrated) in the form of a character or the like to be recognized by an operator, the braking force being produced between the brake pad  10  and the brake disc  20 . The control unit  600  controls the operation of the motor unit  100 . 
     The reduction gear unit  210  includes a first reduction gear  211 , a second reduction gear  212 , a third reduction gear  213 , a fourth reduction gear  214 , and the fifth reduction gear  215 . The first reduction gear  211  is engaged with the driving gear  130  of the motor unit  100  for being combined therewith. The first reduction gear  211  is rotated with the rotational force received from the driving gear  130 . The second reduction gear  212  is connected to the first reduction gear  211  and receives the rotational force from the first reduction gear  211 . The third reduction gear  213  is engaged with the second reduction gear  212  for being combined therewith and receives the rotational force from the second reduction gear  212 . The fourth reduction gear  214  is connected to the third reduction gear  213  and receives the rotational force from the third reduction gear  213 . The fifth reduction gear  215  is connected to the cylinder unit  300  and is supported by the bearing  220  for being rotated. The load sensing unit  400  is mounted on the fifth reduction gear  215 , and the load sensing unit  400  senses the load produced from the axial force of the fifth reduction gear  215 . 
     The reduction gear unit  210  is illustrated with five gears including the first reduction gear  211 , the second reduction gear  212 , the third reduction gear  213 , the fourth reduction gear  214 , and the fifth reduction gear  215 , but is not limited thereto. The number of gears thereof is changeable for different cases, e.g., three gears or the like. 
     In this case, the load sensing unit  400  may be arranged at any one of the gears constituting the reduction gear unit  210  in an axial direction. The load sensing unit  400  may be mounted on the gear of the reduction gear unit  210 , which is connected to the screw bar  310  of the cylinder unit  300 . 
     The fifth reduction gear  215  includes a shaft  215 A and a fifth reduction gear body  215 B. The shaft  215 A is connected to the screw bar  310  of the cylinder unit  300 , and the bearing  220  is disposed or mounted thereon. 
     The load sensing unit  400  senses the load produced from the axial force of the fifth reduction gear  215 . The load sensing unit  400  includes a load cell, arranged in parallel to the bearing  220 , and is in contact with the shaft  215 A. Thus, the load sensing unit  400  may sense the load produced from the axial force of the fifth reduction gear  215 . 
       FIG.  8    is a view illustrating a vehicle brake apparatus according to another embodiment of the present disclosure,  FIG.  9    is a cross-sectional view taken along the line A-A′ of  FIG.  8   ,  FIG.  10    is a cross-sectional view taken along the line B-B′ of  FIG.  8   ,  FIG.  11    is a view illustrating the vehicle brake apparatus according to the another embodiment of the present disclosure when viewed from another direction,  FIG.  12    is a partially exploded perspective view of  FIG.  11   ,  FIG.  13    is an enlarged view of a portion B of  FIG.  12   ,  FIG.  14    is an enlarged view of a portion C of  FIG.  12   , and  FIG.  15    is an exploded perspective view of main components of  FIG.  12   . 
     Hereinafter, the vehicle brake apparatus according to another embodiment of the present disclosure will be described. Detailed descriptions of another embodiment for the same contents as in the embodiment of the present disclosure are omitted. 
     Referring to  FIGS.  8  to  15   , the load sensing unit  400  in a vehicle brake apparatus  2  according to another embodiment of the present disclosure includes an elastic member  410 , a magnet  420 , and a position sensor  430 . The elastic member  410  elastically supports the bearing  220 . 
     The magnet  420  is installed in the bearing  220 , and the position of the magnet  420  is varied by an elastic force of the elastic member  410 . 
     The position sensor  430  is installed in the housing unit  500 , determines the position of the magnet  420  by sensing a magnetic field of the magnet  420 , and senses the load according to the axial force of the fifth reduction gear  215  based on the position of the magnet  420 . 
     The control unit  600  receives sensing information from the position sensor  430  of the load sensing unit  400  and outputs the braking force produced between the brake pad  10  and the brake disc  20  based on the sensing information. Based on the sensing information received from the position sensor  430  of the load sensing unit  400 , the control unit  600  may output and show the braking force on a display (not illustrated) in the form of a character or the like to be recognized by an operator, the braking force being produced between the brake pad  10  and the brake disc  20 . 
     The bearing  220  includes a bearing inner ring  221 , a bearing outer ring  222 , and a plurality of balls  223 . The bearing inner ring  221  surrounds the shaft  215 A of the fifth reduction gear  215 . The bearing inner ring  221  supports the rotation of the fifth reduction gear  215 . The bearing outer ring  222  surrounds the bearing inner ring  221 , is provided with the magnet  420  installed therein, and is elastically supported by the elastic member  410 . The plurality of balls  223  is disposed or arranged between the bearing inner ring  221  and the bearing outer ring  222 . 
     In this way, the load sensing unit  400  is arranged on the reduction gear unit  210  in such a manner as to sense the load produced from the axial force of the reduction gear unit  210 , and thus the weight of the load sensing unit  400  is reduced compared to the related art that applies the load sensing unit to the cylinder. That is, the weight of the load sensing unit is from 40 KN to 60 KN in the related art, whereas the weight of the load sensing unit  400  according to the present disclosure may be under 1 KN which is reduced by at least one fortieth from the weight in the related art. 
     As the weight of the load sensing unit  400  is reduced, the overall weight of the vehicle brake apparatus  1  can be reduced, and thus an automotive electronic component thereof can decrease, resulting in cost reduction in parts of the apparatus. Furthermore, even for various vehicle types, the weight change of the load sensing part  400  is less than in the related art, resulting in easier layout work in designing. 
     The present disclosure has been described with reference to the exemplary embodiments illustrated in the drawings, but this is only for illustrative purposes, and those skilled in the art will appreciate that various modifications and other equivalent exemplary embodiments are possible therefrom. 
     Thus, the true technical scope of the disclosure should be defined by the following claims.