Patent Publication Number: US-2006017321-A1

Title: Vehicle brake hydraulic pressure controller

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to a brake hydraulic pressure controller mounted in a vehicle hydraulic brake system including a hydraulic brake booster (HB), an anti-lock brake system (ABS) and/or a vehicle stability control system (VSC).  
      As shown in  FIG. 7  (and as disclosed in JP patent publication 2001-260846), the brake hydraulic pressure controller (designated by numeral  3 ) of such a vehicle hydraulic system is disposed between a brake pedal  1  and brake wheel cylinders  4  ( 4   a ,  4   b ,  4   c  and  4   d ). The brake hydraulic pressure controller  3  includes pressure increasing control valves and pressure reducing control valves. By selectively closing and opening the respective control valves, hydraulic pressures in the individual brake wheel cylinders  4  can be controlled.  
      Many of today&#39;s vehicle hydraulic brake systems have an anti-lock brake function, a vehicle stability control function, etc. Such functions necessitate an increased number of parts of e.g. the brake hydraulic pressure controller  3 . Still, it is desired or required that the brake hydraulic controller  3  and other units or devices be as small as possible.  
      There are various types of brake hydraulic pressure controllers, including the one shown in  FIGS. 7 and 8 . The brake hydraulic pressure controller  3  shown in  FIGS. 7 and 8  is a part of a hydraulic brake booster. The hydraulic brake booster includes a master cylinder  2  having a piston rod  5   a  coupled to the brake pedal  1 . The master cylinder  2  has a body  6  which is integral with a housing  10  of the brake hydraulic pressure controller  3 . The controller  3  includes various types of hydraulic pressure control valves  11  mounted in its housing  10 . Pipes r extend from the body  6  to the front and rear brake wheel cylinders. (This type of hydraulic brake booster is disclosed in JP patent publication 08-11696.)  
      In this hydraulic brake booster, when the brake pedal  1  is depressed or released, hydraulic fluid a in the master cylinder is supplied into the brake wheel cylinders  4  or hydraulic fluid a is discharged from the wheel cylinders  4 . When the respective hydraulic pressure control valves  11  are turned on or off by an electronic control unit  20  of the brake hydraulic pressure controller  3 , too, hydraulic fluid a is supplied into or discharged from the brake wheel cylinders  4 . Thus, the hydraulic pressure in the wheel cylinders  4  can be controlled both manually through the brake pedal  1  and by the electronic control unit  20 . When hydraulic fluid a is supplied into the brake wheel cylinders  4 , hydraulic fluid is replenished into the brake hydraulic pressure controller  3  from an accumulator  6   a  by activating a pump  7  with a motor  8 . Hydraulic fluid returned into the brake hydraulic pressure controller  3  flows back into a reservoir  9 .  
      Typically, the hydraulic pressure control valves  11  are mounted in the housing  10  in a plurality of rows as shown in  FIG. 9 . The electronic control unit  20  for controlling the valves  11  is mounted on the outside of the housing  10 . The electronic control unit  20  includes a casing  21 . A control circuit board  22  for controlling the hydraulic pressure control valves  11  is mounted in the casing  21 .  
      Typically, as shown in  FIGS. 9 and 10 , each hydraulic pressure control valve  11  has its coil connected to a control circuit on the circuit board  22  through connecting pieces  23  extending vertically from the valve  11  through the circuit board  22  and connected to its control circuit. (This type of hydraulic pressure controller is disclosed in JP patent publication 11-165627, particularly its  FIG. 7 .)  
      In this arrangement, as shown in  FIG. 10 , the connecting pieces  23  are soldered to the control circuit in areas e that are dispersed from one another. Since the soldering areas e are dispersed from one another, large electronic parts such as a microcomputer M cannot be mounted on the circuit board  22  in its area defined by one-dot chain line in  FIG. 10 . Even small electronic parts D cannot be easily mounted in the area defined by the one-dot chain line because of the presence of dispersed soldering areas e. Thus, it is necessary to increase the size of the circuit board  22  so that the electronic parts D and the microcomputer M can be mounted on the circuit board  22  in its area other than the area defined by the one-dot chain line.  
      Today&#39;s brake hydraulic pressure controllers of e.g. hydraulic brake booster include a large number of (e.g. 12) hydraulic pressure control valves  11 , and also carry many electronic parts D including microcomputers M on its circuit board  22 . Thus, if the connecting pieces  23  are connected to the circuit board  22  in the manner as described above with reference to  FIG. 10 , it is necessary to prepare a large circuit board  22  having a large surface area to mount a greater number of electronic parts D including microcomputers M. This leads to an increase in the size of the casing  21  and thus an increase in the size of the entire brake hydraulic pressure controller  3 .  
      Because today&#39;s vehicles have a large number of parts and devices, it is required that these parts and devices be as small as possible. The brake hydraulic pressure controller  3  has to be also as small as possible.  
      An object of the present invention is to provide a brake hydraulic pressure controller which includes large numbers of hydraulic pressure control valves, electronic parts and microcomputers and is still sufficiently small in size.  
     SUMMARY OF THE INVENTION  
      According to this invention, there is provided a vehicle brake hydraulic pressure controller comprising a housing, a plurality of hydraulic pressure control valves mounted in the housing, and an electronic control unit for controlling the hydraulic pressure control valves, the electronic control unit comprising a casing and a circuit board mounted in the casing so as to oppose the hydraulic pressure control valves, the circuit board carrying a control circuit for controlling the hydraulic pressure control valves, the respective hydraulic pressure control valves being connected to the control circuit through connecting lines, the connecting lines having portions that extend substantially along, while being spaced apart from, a surface of the circuit board facing the hydraulic pressure control valves, whereby the connecting lines are connected to the control circuit at a plurality points in a limited, concentrated area of the circuit board.  
      Since the connecting lines are connected to the control circuit at a plurality of points in a limited, concentrated area of the circuit board, it is possible to reduce the distances between the adjacent terminals to a minimum. Thus, this limited, concentrated area of the circuit board is far smaller than the area defined by the one-dot chain line shown in  FIG. 10 , where the simple vertical connecting pieces  23  are soldered to the control circuit of the circuit board.  
      In  FIG. 10 , electronic parts D including the microcomputers M cannot usually be mounted near the peripheral area c defined by the two-dot chain line. According to the present invention, the connecting lines are arranged such that the areas e where the electronic parts D cannot be mounted are disposed near the peripheral area c or otherwise in a limited, concentrated area or areas. Thus, a sufficiently large space remains on the circuit board  22  where electronic parts D including microcomputers M can be mounted without the need to increase the size of the circuit board  22 .  
      In order to simplify the connecting lines, the connecting points at which the connecting lines are connected to the control circuit on the circuit board may be disposed in a plurality of limited, concentrated area such that each area is located close to one of the hydraulic pressure control valves.  
      From another aspect of the invention, there is provided a vehicle brake hydraulic pressure controller comprising a housing, a plurality of hydraulic pressure control valves mounted in the housing, and an electronic control unit for controlling the hydraulic pressure control valves, the electronic control unit comprising a casing and a circuit board mounted in the casing so as to oppose the hydraulic pressure control valves, the circuit board carrying a control circuit for controlling the hydraulic pressure control valves, the respective hydraulic pressure control valves being connected to the control circuit through connecting lines, the connecting lines extending from the respective hydraulic pressure control valves along a surface of the circuit board facing the hydraulic pressure control valves, while being spaced apart from the surface, to points near a peripheral edge of the circuit board, and then guided onto the circuit board and connected to the control circuit.  
      Each of the hydraulic pressure control valves may be connected to the control circuit at a plurality of points of the circuit board.  
      The connecting lines may comprise bus bars mounted to a partitioning wall provided between the casing and the housing.  
      The bus bars may be embedded in the partitioning wall, or bonded to the front or back side of the partitioning wall.  
      The partitioning wall may be omitted. In this case, the bus bars are supported by the casing so as to extend substantially along, while being spaced apart from, a surface of the circuit board facing the hydraulic pressure control valves.  
      The control circuit on the circuit board to which the connecting lines are connected may be formed on either side of the circuit board. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and objects of the present invention will become apparent from the following description made with reference to the accompanying drawings, in which:  
       FIG. 1  is a partially cutaway front view of a first embodiment;  
       FIG. 2  is a sectional view taken along line A-A of  FIG. 1 ;  
       FIG. 3  is a sectional view taken along line B-B of  FIG. 1 ;  
       FIGS. 4A and 4B  are views similar to  FIG. 3  and showing the bus bars in the top wall  13   a;    
       FIG. 5  is a schematic plan view of a second embodiment;  
       FIG. 6  is a schematic plan view of a third embodiment;  
       FIG. 7  is a schematic view of a vehicle hydraulic brake system;  
       FIG. 8  is a schematic perspective view of a brake hydraulic pressure controller in a hydraulic brake booster;  
       FIG. 9  is a partially cutaway front view of a conventional brake hydraulic pressure controller; and  
       FIG. 10  is a schematic plan view of the conventional controller of  FIG. 9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIGS. 1-3  show the first embodiment, which is a brake hydraulic pressure controller  3  of a hydraulic brake booster of the same type as shown in  FIG. 7 . Thus, elements similar or identical to elements shown in  FIG. 7  are denoted by identical numerals. Like the controller of  FIG. 7 , the controller  3  of the embodiment includes a housing  10  in which are mounted a plurality of hydraulic pressure control valves  11  and sensors  12  in a plurality of rows. An electronic control unit  20  for controlling the hydraulic pressure control valves  11  is mounted on the outer surface of the housing  10 . The electronic control unit  20  includes a casing  21  in which a circuit board  22  for controlling the hydraulic pressure control valves  11  is mounted.  
      The controller  3  includes a plastic case  13  coupled to the housing  10 . When the case  13  is formed, bus bars  14  are embedded in a top wall  13   a  of the case  13 . Through the bus bars  14 , the respective hydraulic pressure control valves  11  are connected to the circuit board  22 . The top wall  13   a  is formed with holes  15  each facing one of the hydraulic pressure control valves  11  and sensors  12 . From the sensors  12 , connecting pieces  16  extend vertically through the corresponding holes  15  and the circuit board  22 , and are electrically connected to respective terminals  24  of a control circuit on the circuit board  22  (see  FIGS. 3 and 4 B).  
      The bus bars  14  have first ends that protrude into the holes  15  facing the respective hydraulic pressure control valves  11  and are electrically connected to coils of the respective valves  11  at points  11   a  (see  FIGS. 1 and 3 ). As shown in  FIGS. 3, 4A  and  4 B, the bus bars  14  extend from the first ends through the top wall  13   a  of the case  13 , which separates the electronic control unit  20  from the housing  10 , to points near the peripheral area c of the circuit board  22  shown in  FIG. 2 . At these points, the bus bars  14  are bent vertically and soldered to terminals  24  of the control circuit on the circuit board  22  near the peripheral area c. The terminals  24  to which the bus bars  14  are connected should be provided as close to the respective hydraulic pressure control valves  11  as possible.  
      The control circuit, which comprise electronic parts D including microcomputers M, is not shown, and is formed in an area S defined by two-dot chain line in  FIG. 2 . A connector C shown in  FIG. 3  is connected to an external connector C 1  which is connected to a power source and/or sensors. A connector C 2  is connected to a power source. A connector C 3  is connected to a motor  8 . These connectors are also connected to the respective terminals  24  on the circuit board  22 .  FIG. 4A  shows the bus bars  14  with the holes  15  of the top walls  13   a  omitted so as to clearly show the position of the bus bars  14  relative to the circuit board  22 .  FIG. 4B  is similar to  FIG. 3  but further shows the portions of the bus bars  14  embedded in the top wall  13   a  by phantom line so as to facilitate understanding on how the bus bars  14  are connected to the coils of the respective hydraulic pressure control valves  11 .  
      In the embodiment, each hydraulic pressure valve  11  has one of its electrodes connected to a pair of terminals  24  on the circuit board through one of the bus bars  14  and the other electrode connected to a pair of terminals  24  on the circuit board  22  through several bus bars  14 . In this hydraulic brake booster, when the brake pedal  1  is depressed or released, hydraulic fluid a in the master cylinder is supplied into the brake wheel cylinders  4  or hydraulic fluid a is discharged from the wheel cylinders  4 . When the respective hydraulic pressure control valves  11  are turned on or off by the electronic control unit  20  of the brake hydraulic pressure controller  3 , too, hydraulic fluid a is supplied into or discharged from the brake wheel cylinders  4 . Thus, the hydraulic pressure in the wheel cylinders  4  can be controlled both manually through the brake pedal  1  and by the electronic control unit  20 .  
      In this embodiment, as will be apparent from FIGS.  2  to  4 B, the bus bars  14  extend from the respective hydraulic pressure control valves  11  to points near the peripheral area c and connected to the terminals  24 . The area S, which is large enough to mount all of the necessary electronic parts D including microcomputers M, is defined inside of the terminals  24 . Thus, the necessary electronic parts D including microcomputers M can be mounted on the circuit board  22  without the need to increase the size of the circuit board  22  and thus the size of the electronic control unit  20  as well as the size of the entire brake hydraulic pressure controller  3 .  
      In the embodiment of FIGS.  1  to  4 , the bus bars  14  are arranged so as to be connected to the terminals  24  near the peripheral area c. But instead, the bus bars  14  may be arranged so as to be connected to the terminals  24  in a corner area b of the circuit board  22  as shown in  FIG. 5 , or in a central area d of the circuit board  22  as shown in  FIG. 6 , or any other limited, concentrated area of the circuit board  22 .  
      The brake hydraulic pressure controller  3  of the embodiment is a controller of a hydraulic brake booster. But the brake hydraulic pressure controller according to the present invention is not limited thereto. For example, it may comprise the housing  10 , two electronic control units each mounted on one of two opposed sides of the housing  10 , and two motors each mounted on one of the two opposed sides of the housing  10 .