Patent Abstract:
A fuel pump includes a case member, which defines a fuel passage and accommodating a pump portion for pumping fuel. A motor portion is provided in the case member, and including a commutator for rectifying electricity supplied to an armature. Positive and negative electrode terminals conduct electricity to the motor portion. An insulative terminal support member supports the positive and negative electrode terminals. Brushes are slidable on the commutator to conduct electricity from the positive and negative electrode terminals to the commutator. Brush springs apply resilient forces to bias the brushes against the commutator. The terminal support member has a load bearing portion abutting against the brush springs to receive reactive forces of the resilient forces.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and incorporates herein by reference Japanese Patent Application No. 2006-242833 filed on Sep. 7, 2006. 
         [0002]    This application is related to U.S. patent applications (IPICS 106207-US) claiming priorities to the following Japanese Patent Applications, respectively: 
         [0003]    No. 2006-242770 filed on Sep. 7, 2006; and 
         [0004]    No. 2006-242800 filed on Sep. 7, 2006. 
     
     FIELD OF THE INVENTION 
       [0005]    The present invention relates to an electric fuel pump. 
       BACKGROUND OF THE INVENTION 
       [0006]    For example, U.S. Pat. No. 5,520,547 (JP-A-7-91343), and U.S. Pat. No. 6,478,613 (JP-T-2002-544425) disclose fuel pumps each having a case member accommodating a pump portion and a motor portion. The pump portion is driven by an armature of the motor portion. 
         [0007]    As disclosed in U.S. Pat. No. 5,520,547, a fuel pump includes a discharge-side cover and case members. The cover and the case members respectively have an outlet and an inlet, and define fuel passages therein. The discharge-side cover includes a bearing holder being insulative and mounted with positive and negative electrode terminals. 
         [0008]    The motor portion is supplied with electricity from an external power source via the positive and negative electrode terminals. Both the terminals have load bearing portions against which one ends of brush springs abut. The other ends of the brush springs abut against the brushes to bias the brushes against a commutator. The load bearing portions provided on both the terminals are also applied with resilient forces of the brush springs. 
         [0009]    Here, a gasoline-alternate fuel, such as high density alcohol petroleum fuel mixture, bio-ethanol, ethanol 100% fuel, and the like, is in great demand. The gasoline-alternate fuel contains a component of high electric conductivity therein. When conventional pumps for gasoline fuel are to be applied to a fuel pump for a gasoline-alternate fuel, as it is, a problem described below is caused. 
         [0010]    Specifically, with the fuel pump described in U.S. Pat. No. 5,520,547, the load bearing portions are provided on both the terminals, and are exposed to the fuel passage. In this structure, the terminals are exposed entirely to the gasoline-alternate fuel containing a component of high conductivity, and consequently, the terminals cause electrochemical corrosion due to exposure to gasoline-alternate fuel. 
       SUMMARY OF THE INVENTION 
       [0011]    In view of the foregoing and other problems, it is an object of the invention to provide a fuel pump capable of pumping electrically conductive fuel and suppressing electrochemical corrosion of a terminal therein. 
         [0012]    According to one aspect of the present invention, a fuel pump includes a case member defining a fuel passage, an inlet, and an outlet. The fuel pump further includes a pump portion provided in the fuel passage for pumping fuel from the inlet to the outlet. The fuel pump further includes a motor portion provided in the case member, the motor portion including an armature for driving the pump portion, the motor portion further including and a commutator for rectifying electricity supplied to the armature. The fuel pump further includes a positive electrode terminal and a negative electrode terminal for conducting electricity to the motor portion. The fuel pump further includes a terminal support member being insulative and supporting the positive electrode terminal and the negative electrode terminal. The fuel pump further includes brushes slidable on the commutator to conduct electricity respectively from the positive electrode terminal and the negative electrode terminal to the commutator. The fuel pump further includes brush springs for respectively applying resilient forces to bias the brushes against the commutator. The terminal support member has a load bearing portion abutting against the brush springs to receive reactive forces of the resilient forces. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
           [0014]      FIG. 1  is a cross sectional view showing a fuel pump; 
           [0015]      FIGS. 2A ,  2 B compose a dihedral view,  FIG. 2A  being an exploded front view showing a discharge-side cover and components to be received in the discharge-side cover of the fuel pump, and  FIG. 2B  being a side view showing the discharge-side cover and the components; 
           [0016]      FIG. 3  is an exploded view showing an assembled body of the components shown in  FIG. 2 ; 
           [0017]      FIGS. 4A ,  4 B,  4 C compose a trihedral view,  FIG. 4A  being a plan view,  FIG. 4B  being a front view, and  FIG. 4C  being a bottom view, each showing the assembled body shown in  FIG. 3 ; 
           [0018]      FIGS. 5A ,  5 B,  5 C compose a trihedral view,  FIG. 5A  being a plan view showing the assembled body shown in  FIG. 3 ,  FIG. 5B  being a front view, and  FIG. 5C  being a side view; 
           [0019]      FIG. 6  is a cross sectional view taken along the line VI-O-VI in  FIG. 4A ; 
           [0020]      FIGS. 7A to 7C  compose a trihedral view showing a molded body including the assembled body, and  FIG. 7D  is a view when being viewed from an arrow VIID in  FIG. 7B ; 
           [0021]      FIGS. 8A to 8D  compose a tetrahedral view,  FIG. 8A  being a front view,  FIG. 8B  being a side view,  FIG. 8C  being a rear view, and  FIG. 8D  being a plan view, each showing a bearing holder shown in  FIGS. 2A ,  2 B; 
           [0022]      FIGS. 9A to 9D  compose a tetrahedral view,  FIG. 9A  being a front view,  FIG. 9B  being a side view,  FIG. 9C  being a rear view, and  FIG. 9D  being a plan view, each showing a state in which the molded body shown in  FIGS. 7A to 7D  is mounted to the bearing holder shown in  FIGS. 2A ,  2 B; 
           [0023]      FIGS. 10A to 10D  compose a tetrahedral view,  FIG. 10A  being a front view,  FIG. 10B  being a side view,  FIG. 10C  being a rear view, and  FIG. 10D  being a plan view, each showing a state in which the discharge-side cover is mounted to the assembled body; 
           [0024]      FIG. 11  is a view showing a fuel pump according to a related art; and 
           [0025]      FIG. 12  is an exploded view showing a discharge-side cover and a bearing holder of the fuel pump shown in  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0026]    A fuel pump according to an embodiment will be described below with reference to  FIGS. 1 to 10D . 
         [0027]    A fuel pump shown in  FIG. 1  is an in-tank type pump mounted in a fuel tank of, for example, a vehicle. Accordingly, the fuel pump is entirely submerged in fuel. The fuel pump supplies fuel from a fuel tank to an engine. The fuel, which is pumped using the fuel pump, is one, such as high density alcohol petroleum fuel mixture, bio-ethanol, ethanol 100% fuel, containing a component of high electric conductivity. 
         [0028]    As follows, a construction of the fuel pump will be described with reference to  FIG. 1 . The fuel pump includes a motor portion  10  and a pump portion  20  driven by the motor portion  10  to raise a fuel as drawn in pressure. 
         [0029]    The motor portion  10  includes a direct current motor with a brush. The fuel pump includes a substantially cylindrical-shaped housing  11 . The housing  11  has an inner periphery, to which permanent magnets  12  are annually provided along the circumferential direction thereof. An armature  13  is arranged on the inner periphery of the annular permanent magnet  12  to be concentric with the annular permanent magnet  12 . The armature  13  is accommodated rotatably in the inner space of the housing  11 . 
         [0030]    The armature  13  includes a core  133  and a coil (not shown) wound around the outer periphery of the core  133 . A commutator  15  is disk-shaped, and mounted on the opposite side of the pump portion  20  with respect to the armature  13 . The commutator  15  includes multiple segments  151  arranged along a rotative direction thereof. The segments  151  are formed of, for example, carbon, and are electrically insulated from one another via air gaps and an insulative resin material. 
         [0031]    The commutator  15  is in contact with brushes  61 ,  62  (see  FIGS. 2A ,  2 B), which are biased by brush springs  71 ,  72  serving as resilient members. The brush spring  71  and the brush  61  are present on a positive electrode side, and the brush spring  72  and the brush  62  are present on a negative electrode side. Depiction of the brush springs  71 ,  72  and the brushes  61 ,  62  is omitted in  FIG. 1 . 
         [0032]    The pump portion  20  includes an impeller  23  arranged between a casing body  21  and a pump cover  22 , and the like. The casing body  21  and the pump cover  22  define a substantially C-shaped pump flow passage  24 . The casing body  21  and the pump cover  22  therebetween rotatably accommodate the impeller  23 . 
         [0033]    The casing body  21  is fixed by being press-fitted to one end side of the housing  11  with respect to the axial direction thereof. A bearing  25  is provided centrally of the casing body  21 . The pump cover  22  is fixed to one end of the housing  11  by crimping or the like in a state where being connected with the casing body  21 . One end of a shaft  131  (rotation axis) of the armature  13  is radially supported rotatably by the bearing  25 . The other end of the shaft  131  is radially supported rotatably by a bearing  26 . 
         [0034]    The pump cover  22  has an inlet  221  through, which a fuel is drawn. The impeller  23  has a peripheral edge defining a vane groove therein. The impeller  23  rotates in the pump flow passage  24 , thereby drawing fuel from an unillustrated fuel tank into the pump flow passage  24  through the inlet  221 . The fuel drawn into the pump flow passage  24  is raised in pressure by rotation of the impeller  23 , and discharged to a space  14  of the motor portion  10 . 
         [0035]    A bearing holder  30  and a discharge-side cover  40  are mounted at the other end of the housing  11 , that is, on the opposite side of the pump cover  22  with respect to the casing body  21 . The bearing holder  30  is interposed and fixed between the discharge-side cover  40  and the housing  11 . The discharge-side cover  40  is fixed to the housing  11  by crimping. 
         [0036]    The housing  11  and the pump cover  22  construct a case member. 
         [0037]    The discharge-side cover  40  includes a fuel discharge portion  41 . The fuel discharge portion  41  accommodates a check valve  43  for opening and closing a fuel passage  42  in the fuel discharge portion  41 . When pressure of fuel in the fuel pump becomes greater than a predetermined value, the check valve  43  opens the fuel passage  42 . The fuel is raised in pressure by the pump portion  20 , and supplied from the outlet  44  to the outside of the fuel pump through an unillustrated piping connected to an outlet  44  of the fuel discharge portion  41 . 
         [0038]    As shown in  FIGS. 2A ,  2 B, a molded body  50  described later is interposed and fixed between the bearing holder  30  and the discharge-side cover  40 . Brushes  61 ,  62  are assembled to the bearing holder  30  to be axially movable. Brush springs  71 ,  72  bias downward the upper end surfaces of the brushes  61 ,  62  in  FIGS. 2A ,  2 B. The upper end surfaces of the brush springs  71 ,  72  abut against a load bearing portion  501  of the molded body  50  in  FIGS. 2A ,  2 B. 
         [0039]    Subsequently, the structure of the molded body  50  will be described with reference to  FIGS. 3 to 7D . The molded body  50  is formed to be in a state shown in  FIGS. 7A to 7D  by molding an assembled body  50 K shown in  FIGS. 5A to 5C . First, the structure of the assembled body  50 K will be described below. 
         [0040]    As shown in  FIG. 3 , the assembled body  50 K is constructed by mounting external connection terminals  51 ,  52 , choke coils  53 ,  54 , and brush terminals  55 ,  56  to a holder  57  of an insulative body. The external connection terminal  51 , the choke coil  53 , and the brush terminal  55  are present on a positive electrode side, and the external connection terminal  52 , the choke coil  54 , and the brush terminal  56  are present on a negative electrode side. 
         [0041]    The external connection terminals  51 ,  52 , the choke coils  53 ,  54 , the brush terminals  55 ,  56 , and the brushes  61 ,  62 , are electrically connected with each other. Electricity is supplied from an external power source to the fuel pump through the external connection terminals  51 ,  52 . The external connection terminals  51 ,  52  are connected with unillustrated other external terminals. Electricity flows through the choke coils  53 ,  54 , the brush terminals  55 ,  56 , and the brushes  61 ,  62  in this order, so that the electricity is supplied to a coil (not shown) of the armature  13  through the brushes  61 ,  62  and the commutator  15 . 
         [0042]    The choke coils  53 ,  54  serve to decrease electric noise such as high frequency component caused when the brushes  61 ,  62  sequentially slide on the respective segments  151  of the commutator  15 . In addition, the choke coils  53 ,  54  are constructed of coils  532 ,  542  and cores  531 ,  541 . The coils  532 ,  542  are formed by winding wires around the cores  531 ,  541  each being columnar-shaped. The core  531  and the coil  532  are present on a positive electrode side. The core  541  and the coil  542  are present on a negative electrode side. 
         [0043]    As shown in  FIGS. 4A to 4C , the holder  57  has the upper surface side defining insertion holes  571 ,  572 ,  573 . As shown in  FIGS. 5A to 5C , the external connection terminals  51 ,  52  are respectively inserted into the insertion holes  571 . The choke coils  53 ,  54  are respectively inserted into the insertion holes  572 . The brush terminals  55 ,  56  are respectively inserted into the insertion hole  573 . 
         [0044]    As shown in  FIGS. 2A ,  2 B,  3 ,  5 A to  5 C, connecting portions  511 ,  521  of the external connection terminals  51 ,  52  and connecting portions  533 ,  543  of the choke coils  53 ,  54  are respectively connected together by thermal crimping or fusing. Connecting portions  534 ,  544  of the coils  532 ,  542  and connecting portions  551 ,  561  of the brush terminals  55 ,  56  are connected together by thermal crimping or fusing. In addition, connecting portions  552 ,  562  of the brush terminals  55 ,  56  and pigtails (strand wire)  611 ,  621  connected to the brushes  61 ,  62  are connected together by thermal crimping or fusing. 
         [0045]    Subsequently, a construction of the choke coils  53 ,  54  mounted to the insertion holes  572  of the holder  57  will be described in detail with reference to  FIGS. 4A and 6 . Only a structure of the insertion hole  572  for the choke coil  54  on the negative electrode side is illustrated in  FIG. 6 , and a structure of the insertion hole  572  for the choke coil  53  on the positive electrode side is also substantially the same as that on the negative electrode side, and so a description therefore is omitted. 
         [0046]    As shown in  FIG. 6 , an inner peripheral surface  574 a of the insertion hole  572  and the coil  542  of the choke coil  54  therebetween define a clearance. The resin is press-charged into the clearance when the assembled body  50 K is molded of a resin. 
         [0047]    The coil  542  is partially inserted in the insertion hole  572 . The connecting portion  543  is inserted in an insertion groove  574 . The connecting portion  544  is inserted in an insertion groove  575 . The clearance between the inner surfaces, which respectively define the insertion grooves  574 ,  575 , and the coil  542  is also press-charged with the resin as described above. 
         [0048]    Each of lower ends of the insertion grooves  574 ,  575  defines a core stopper  576 , which latches an insertion-side end surface of the core  541  to restrict axial movements of the core  541 . The core stopper  576  is located in the hatched region indicated by the reference numeral  576  in  FIG. 4A . The core stopper  576  is capable of restricting the core  541  from downwardly moving in  FIG. 6  when the resin is press-charged into the clearance around the coil  542 . 
         [0049]    A lower end of an inner peripheral surface  577  of the insertion hole  572  defines a coil stopper  578 , which latches an insertion-side end surface of the coil  542  to restrict axial movements of the of the coil  542 . The coil stopper  578  is located in the hatched region indicated by the reference numeral  578  in  FIG. 4A . The coil stopper  578  is capable of restricting the coil  542  from downwardly moving in  FIG. 6  when the resin is press-charged into the clearance around the coil  542 . 
         [0050]    The coil  542  is wound around the core  541  in a compacted state, so that the core  541  is clamped by the coil  542 . Accordingly, the coil  542  is restricted from being moved downward in  FIG. 3  from the core  541  by its own weight. When the choke coil  54  is mounted to the insertion hole  572 , simple insertion of the choke coil  54  into the insertion hole  572  may cause only the coil  542  to abut against the coil stopper  578  but the core  541  does not abut against the core stopper  576 . Therefore, the choke coil  54  is inserted into the insertion hole  572 , thereafter, only the core  541  is pushed downward in  FIG. 6  against the core stopper  576 . Thus, the choke coil  54  is assembled such that the coil  542  and the core  541  are respectively abutted against the coil stopper  578  and the core stopper  576  before being molded with the resin. 
         [0051]    The holder  57  has insertion openings  570 , through which the choke coils  53 ,  54  are inserted into the insertion holes  572 , and through-holes  579 , which are located on the opposite sides to the insertion openings  570 . The through-holes  579  communicate the inside of the insertion hole  572  with the outside of the insertion hole  572 . 
         [0052]    In press-charging of resin into the insertion holes  572  to resin-mold the choke coils  53 ,  54 , the resin is press-charged from the insertion openings  570  into the insertion holes  572 . The resin being press-charged flows outside the insertion holes  572  through the through-holes  579 . Therefore, the resin can be enhanced in flowability between the inner peripheral surfaces  577  of the insertion holes  572  and the coils  532 ,  542 , as compared with a structure where the insertion holes  572  are in the form of a blind hole without the through-holes  579 . Thus, it is possible to decrease failure in filling of the resin into the clearances between the inner peripheral surfaces  577  of the insertion holes  572  and the coils  532 ,  542 . 
         [0053]    Subsequently, referring to  FIG. 7A to 7D , a detailed structure of the molded body  50 , which is formed by resin-molding the assembled body  50 K, will be described. 
         [0054]    The molded body  50  is constructed of a molded portion  50 M and the assembled body  50 K. A portion of the assembled body  50 K other than a portion described below is covered with the molded portion  50 M. The bottom surface of the holder  57  being a hatched portion in  FIG. 7D  is exposed from the bottom surface of the molded portion  50 M. The external connection terminals  51 ,  52  being hatched portions in  FIGS. 7A to 7C  extend from the upper surface of the molded portion  50 M. The connecting portions  552 ,  562  of the brush terminals  55 ,  56  being hatched portions in  FIGS. 7A to 7D  extend from sides of the molded portion  50 M. 
         [0055]    In this manner, the external connection terminal  51  on the positive electrode side and the external connection terminal  52  on the negative electrode side are resin-molded in a state where being mounted to the holder  57  of the insulative body. The external connection terminals  51 ,  52 , the choke coils  53 ,  54 , and the brush terminals  55 ,  56  can be decreased in area exposed to the fuel passage  46 . Accordingly, it is possible to suppress electric corrosion of both the external connection terminals  51 ,  52 , and to decrease a fear of failure in conduction and breakage of both the external connection terminals  51 ,  52 . 
         [0056]    In addition, the holder  57  and the molded portion  50 M in the embodiment serve as a “terminal support member”. 
         [0057]    Subsequently, a structure of the molded body  50  being fixed to the bearing holder  30  and the discharge-side cover  40 , will be described in detail with reference to  FIGS. 8A to 9D . 
         [0058]    As shown in  FIGS. 8A to 8D , the bearing holder  30  has a projection  37  extending toward the molded body  50 . On the other hand, the bottom surface of the holder  57 , which is exposed from the molded portion  50 M, has a recess  57   a,  into which the projection  37  is to be press-fitted. As shown in  FIGS. 9A to 9D , the projection  37  is press-fitted into the recess  57   a,  so that the molded body  50  is fixed to the bearing holder  30 . 
         [0059]    The molded body  50  is press-fitted and fixed to the bearing holder  30 , so that the molded body  50  is temporarily mounted to the bearing holder  30 , until the discharge-side cover  40  surrounds the bearing holder  30  from the upward in  FIG. 9A , as depicted by the two-dot chain lines in  FIG. 9A , and crimped to the housing  11 . The molded body  50  is interposed and fixed between the bearing holder  30  and the discharge-side cover  40 , and the discharge-side cover  40  is crimped and fixed to the housing  11 . 
         [0060]    The bearing holder  30  includes a latch portion  31  axially extending to latch the circumferential periphery of the permanent magnet  12 . The bearing holder  30  has a bearing holding hole  32 , into which the bearing  26  is press-fitted and held. 
         [0061]    The bearing holder  30  includes a brush holding portion  33  extending upward in  FIG. 9A . The brush holding portion  33  has a brush holding hole  34  ( FIG. 8D ) extending vertically in  FIG. 9A . The brushes  61 ,  62  and the brush springs  71 ,  72  are held in the brush holding hole  34  such that the brushes  61 ,  62  are vertically movable in the brush holding hole  34 . The brush holding portions  33  have side surfaces respectively defining notched holes  35 , in which the pigtails  611 ,  621  are arranged. The bearing holder  30  has a through-hole  36 , which defines a fuel passage. Fuel flows from the housing  11  into the discharge-side cover  40  through the through-hole  36 . 
         [0062]    As shown in  FIGS. 7C to 7D  and  9 A to  9 D, the upper surface portion of the molded portion  50 M of the molded body  50  has a projection  502 . The projection  502  extends from a portion between the external connection terminal (positive electrode terminal)  51  on the positive electrode side and the external connection terminal (negative electrode terminal)  52  on the negative electrode side. The projection  502  is shaped to extend along the upper surface of the molded portion  50 M in a manner to partition both the external connection terminals  51 ,  52  from one another, as shown in  FIG. 9D . As shown in  FIG. 7B , the external connection terminal  51  has a root portion  512  on the positive electrode side. The external connection terminal  52  has a root portion  522  on the negative electrode side. The projection  502  separates the root portion  512  of the positive electrode terminal  51  from the root portion  522  of the negative electrode terminal  52 . 
         [0063]    The inner surface of the discharge-side cover  40  has a portion, which is opposed to the projection  502  and defining a recess  45 . The recess  45  is shaped along a convex surface of the projection  502 . The recess  45  extends in a manner to partition both the external connection terminals  51 ,  52  from each other, similarly to the projection  502 . 
         [0064]    In this structure, the upper surface of the molded portion  50 M and the inner surface of the discharge-side cover  40  therebetween define a clearance  503  (see  FIG. 9A ). The clearance  503  is shaped so as to meander between the projection  502  and the recess  45  in  FIG. 9A . Accordingly, a creeping distance between the root portion  512  of the external connection terminal  51  on the positive electrode side and the root portion  512  of the external connection terminal  52  on the negative electrode side becomes large, as compared with a structure, which does not have the projection  502  and the recess  45 . Therefore, it is possible to restrict fuel present in the clearance  503  from causing electric corrosion of both the terminals  51 ,  52 . 
         [0065]    In addition, referring to  FIG. 1 , the outer surface of the discharge-side cover  40  defines a connector housing  47  to accommodate therein the external connection terminal  51  on the positive electrode side and the external connection terminal  52  on the negative electrode side. 
         [0066]    As shown in  FIG. 10D , the connector housing  47  has a partition  473 . The partition  473  separates the internal space of the connector housing  47  into a space  471 , which accommodates the external connection terminal  51  on the positive electrode side, and a space  472 , partition  473  the external connection terminal  52  on the negative electrode side. In other words, the partition  473  is shaped to extend in a manner to partition both the external connection terminals  51 ,  52  from one another. 
         [0067]    Thereby, a creeping distance between the external connection terminal  51  on the positive electrode side and the external connection terminal  52  on the negative electrode side, which are located in the connector housing  47 , becomes large, as compared with the structure where the partition  473  is not provided. Therefore, fuel entering the connector housing  47  can be restricted from causing electric corrosion of both the terminals  51 ,  52 . 
         [0068]    Both the external connection terminals  51 ,  52  are connected with an external terminal (not shown) via a connector device. That is, the connector device such as a connector housing (not shown) provided on the external terminal is fitted to the connector housing  47 , so that the external terminal are electrically connected with the external connection terminals  51 ,  52 . 
         [0069]    Fuel may enter from the fuel tank into both the connector housings  47 . In this state, both the external connection terminals  51 ,  52  are in contact with fuel in the connector housing  47 . 
         [0070]    As shown in  FIGS. 10A to 10D , the external connection terminals  51 ,  52  are extended and exposed from the upper surface of the discharge-side cover  40 . The unillustrated external terminal is connected to the external connection terminals  51 ,  52  in this state. In this connection, the external terminal may be press-fitted to and connected to the external connection terminals  51 ,  52 , or a connector housing may be provided on the upper surface of the discharge-side cover  40  and connected to a connector housing of the external terminal by connector-fitting. 
         [0071]    Subsequently, a procedure for mounting the assembled body shown in  FIGS. 10A to 10D  will be described. 
         [0072]    First, as shown in  FIG. 3 , the external connection terminals  51 ,  52  and the brush terminals  55 ,  56  are press-fitted respectively into the insertion holes  571 ,  573  of the holder  57 . In addition, the choke coils  53 ,  54  are respectively inserted into the insertion holes  572  of the holder  57 . In this insertion, the insertion-side end surfaces of the coils  532 ,  542  are caused to abut against the coil stoppers  578 , and thereafter, the core  541  is pushed to cause the insertion-side end surface of the core  541  to abut against the core stopper  576 . Thus, the external connection terminals  51 ,  52 , the choke coils  53 ,  54 , and the brush terminals  55 ,  56  are mounted to the holder  57 . 
         [0073]    Thereafter, connection in the following locations is made by thermal crimping or fusing. Specifically, the connecting portions  511 ,  521  of the external connection terminals  51 ,  52  and the connecting portions  533 ,  543  of the choke coils  53 ,  54  are connected together, connecting portions  534 ,  544  of the choke coils  53 ,  54 , and connecting portions  551 ,  561  of the brush terminals  55 ,  56  are connected together, and the connecting portions  552 ,  562  of the brush terminals  55 ,  56  and the pigtails  611 ,  621  are connected together. Thus, the assembled body  50 K shown in  FIGS. 5A ,  5 B,  5 C is constructed. 
         [0074]    Subsequently, the portion of the assembled body  50 K, other than the bottom surface of the holder  57 , the external connection terminals  51 ,  52 , and the connecting portions  552 ,  562  of the brush terminals  55 ,  56 , is molded with resin. The resin is press-charged into the insertion holes  572  to resin-mold the choke coils  53 ,  54 . Specifically, molten resin is press-charged from the side of the insertion openings  570  into the insertion holes  572 , and caused to flow from the through-holes  579  to the outside of the insertion holes  572 . Thereby, the resin is press-charged into the clearance defined between the inner peripheral surface  574 a of the insertion hole  572  and the coil  542  of the choke coil  54 . Thus the molded body  50  constructed of the molded portion  50 M and the assembled body  50 K is formed, as shown in  FIGS. 7A to 7D . 
         [0075]    Subsequently, the brushes  61 ,  62  and the brush springs  71 ,  72  are inserted into the brush holding portion  33  of the bearing holder  30 . Thereafter, the molded body  50  is temporarily mounted to the bearing holder  30  in a state in which the brushes  61 ,  62  and the brush springs  71 ,  72  are held by press-fitting the recess  57   a  of the molded body  50  onto the projection  37  of the bearing holder  30 . 
         [0076]    Here, in the temporarily mounted state, the pigtails  611 ,  621  are caught by a lower end  351  ( FIG. 8D ) of the bearing holder  30 , which is located at lowermost ends of the notched holes  35 . Subsequently, the brush springs  71 ,  72  are respectively interposed between the brushes  61 ,  62  and the load bearing portion  501  of the molded body  50  in a state, in which the pigtails  611 ,  621  are caught and the brush springs  71 ,  72  are resiliently deformed. According to the embodiment, the bearing holder  30  and the molded body  50  are press-fitted and fixed together via the projection  37  and the recess  57   a.  Therefore, the molded body  50  can be restricted from floating from the bearing holder  30  due to being applied with the resilient force caused by the resilient deformation of the brush springs  71 ,  72 . Thus, the mounting work of the molded body  50  to the bearing holder  30  can be facilitated, and workability thereof can be enhanced. 
         [0077]    Thereafter, the discharge-side cover  40  is caused to cover the bearing holder  30  from the upward in  FIGS. 2A ,  2 B, so that the molded body  50  is interposed between the bearing holder  30  and the discharge-side cover  40 . Thereby, the molded body  50  is held in a state of being accommodated in the discharge-side cover  40 , and the assembled body shown in  FIGS. 10A to 10D  is constructed. 
         [0078]    Thereafter, the fuel pump in a state shown in  FIG. 1  is manufactured by inserting the assembled body shown in  FIGS. 10A to 10D  into the end of the housing  11  opposite to the pump portion  20  and crimping the discharge-side cover  40  to be fixed to the housing  11 . 
         [0079]    Subsequently, a brief description will be given to an operation of the fuel pump constructed in the manner described above. 
         [0080]    The external power source, for example, supplies electricity to the external connection terminals  51 ,  52 , so that the electricity flows through the choke coils  53 ,  54 , the brush terminals  55 ,  56 , the pigtails  611 ,  621 , and the brushes  61 ,  62  in this order to flow to the segments  151  of the commutator  15 . Thereby, the armature  13  rotates, and the impeller  23  rotates together with the shaft  131  of the armature  13 . 
         [0081]    Consequently, fuel in the unillustrated fuel tank is drawn from the inlet  221  to be raised in pressure by rotation of the impeller  23 . The fuel having been raised in pressure is discharged to the space  14  of the motor portion  10  to flow through the fuel passage around the armature  13  in the housing  11 , and further flows into the fuel passage  46  (see  FIG. 1 ) located in the discharge-side cover  40  through the through-hole  36 . 
         [0082]    The clearance  503  defined between the upper surface of the molded portion  50 M and the inner surface of the discharge-side cover  40  is communicated to the fuel passage  46  in the discharge-side cover  40 , accordingly, the fuel flowing into the fuel passage  46  may enter the clearance  503 . 
         [0083]    Thereafter, the fuel flowing into the fuel passage  46  in the discharge-side cover  40  upwardly biases the check valve  43  in  FIG. 1 , thereby being discharged toward an internal combustion engine of a vehicle through the outlet  44  of the fuel discharge portion  41 . 
         [0084]    As follows, an example structure of a fuel pump is described. 
         [0085]    As shown in  FIGS. 11 ,  12 , a fuel pump includes a discharge-side cover  40 , which has an outlet  44  for fuel, and case members  11 ,  22 , which has an inlet  221 . The discharge-side cover  40  and the case members  11 ,  22  define fuel passages  46 ,  14  therein. The discharge-side cover  40  has a bearing holder  30  being an insulative body. A pump portion  20  constructed of an impeller  23  and the like is driven by a motor portion  10 , which is constructed by an armature  13  and the like, and draws fuel from the inlet  221  to pressure feed the fuel toward the outlet  44 . 
         [0086]    As shown in  FIG. 12 , a positive electrode terminal  52  and a negative electrode terminal  52  are mounted to the bearing holder  30 . The positive and negative electrode terminals  52  are supplied with electric power, which serves as a drive source for the motor portion  10 , from an external power source. 
         [0087]    Both the terminals  52  respectively have load bearing portions  56   a  against which one ends of unillustrated brush springs abut. The other ends of the brush springs abut against unillustrated brushes, so that the brushes are biased against a commutator  15  with resilient forces of the brush springs. The load bearing portions  56   a  provided on both the terminals  52  are applied with resilient forces of the brush springs. 
         [0088]    Arrows L 1  to L 4  in  FIG. 11  indicate flow of fuel. When the pump portion  20  is driven, fuel is drawn from the inlet  221  (see the arrow L 1 ) to flow through the fuel passage  14  in the housing  11  (see the arrow L 2 ), and then flows through the fuel passage  46  in the discharge-side cover  40  (see the arrow L 3 ) to be discharged through the outlet  44  (see the arrow L 4 ). 
         [0089]    Here, a gasoline-alternate fuel, such as high density alcohol petroleum fuel mixture, bio-ethanol, ethanol 100% fuel, and the like, is in great demand. Since the gasoline-alternate fuel contains a component of high electric conductivity therein, a problem described below is caused when the pump shown in  FIGS. 11 ,  12  are applied to a fuel pump for a gasoline-alternate fuel, as it is. 
         [0090]    Specifically, with the fuel pump shown in  FIGS. 11 ,  12 , both the terminals  52  respectively have the load bearing portions  56   a  with which resilient forces of the brush springs are applied. Both the terminals  52  are exposed to the fuel passage  46 , and consequently, both the terminals  52  are exposed entirely to the gasoline-alternate fuel containing a component of high conductivity (see the arrow L 3  in  FIG. 11 ). Consequently, the terminals cause electrochemical corrosion due to exposure to gasoline-alternate fuel, and hence failure of conduction and breakage of the terminals  52  are brought about. 
         [0091]    By contrast, in the structure of the embodiment shown in  FIGS. 1 to 10C , the molded body  50  is constructed of the external connection terminals  51 ,  52 , the holder  57 , the molded portion  50 M, and the like. The molded portion  50 M of the molded body  50  includes the load bearing portion  501 , which is applied with the resilient force of the brush springs  71 ,  72 . 
         [0092]    The load bearing portions  56   a,  which correspond to the conventional external connection terminals  51 ,  52  shown in  FIG. 11 , are molded with resin and partially construct the molded portion  50 M in the embodiment. The molded portion  50 M is molded with resin to partially construct the load bearing portion  501 . 
         [0093]    Therefore, it is possible to decrease areas, via which the external connection terminals  51 ,  52  are exposed to the fuel passage  46 , as compared with the conventional construction, in which the external connection terminals  51 ,  52  also serve as load bearing portions. Accordingly, even in the case where the fuel pump is used for gasoline-alternate fuel containing a component of high electric conductivity therein, the external connection terminals  51 ,  52  can be protected from electric corrosion, so that failure of conduction and breakage of the external connection terminals  51 ,  52  can be reduced. 
         [0094]    In addition, the molded body  50  and the bearing holder  30  are fixed together by press-fitting the projection  37  to the recess  57   a,  so that the molded body  50  is mounted to the bearing holder  30  and the discharge-side cover  40 . Therefore, as described above, the molded body  50  can be restricted from upwardly floating from the bearing holder  30  due to being applied with the force caused by the resilient deformation of the brush springs  71 ,  72 . Accordingly, the mounting work can be improved in workability. 
       Other Embodiments 
       [0095]    According to the embodiment, the load bearing portion  501  is provided to the molded portion  50 M. Alternatively, a load bearing portion may be provided on the holder  57 . 
         [0096]    According to the embodiment, the projection  37  is provided on the bearing holder  30  and the recess  57   a  is formed on the holder  57 . Alternatively, the bearing holder  30  may be made partially concave and the holder  57  may be partially made projection. 
         [0097]    According to the embodiment, the recess  57   a  is formed on the holder  57 . Alternatively, a recess may be formed on the molded portion  50 M, and the projection  37  may be press-fitted into the recess. 
         [0098]    According to the embodiment, the holder  57  and the molded portion  50 M are separately resin-molded, and the holder  57  and the molded portion  50 M construct the terminal support member. Alternatively, the holder  57  and the molded portion  50 M may be integrally resin-molded. 
         [0099]    That is, for example, the holder  57  may be omitted, and a terminal support member having both the outline shape of the molded body  50  and the outline shape of the holder  57  shown in  FIGS. 7A to 7D , may be formed. In addition, for example, the molded portion  50 M may be omitted, and only the holder  57  may construct a terminal support member having both the outline shape of the molded body  50  and the outline shape of the holder  57  shown in  FIGS. 7A to 7D . Furthermore, a load bearing portion may be provided to the holder  57 . 
         [0100]    According to the embodiment, a terminal support member, which is constructed by the holder  57  and the molded portion  50 M, and the bearing holder  30  are separately resin-molded. Alternatively, the terminal support member and the bearing holder  30  may be integrally resin-molded. 
         [0101]    According to the embodiment, the external connection terminals  51 ,  52 , the choke coils  53 ,  54 , the brush terminals  55 ,  56 , and the holder  57  are resin-molded. Alternatively, it suffices that at least the external connection terminals  51 ,  52  are resin-molded. In addition, for example, the external connection terminals  51 ,  52  may be resin-molded together with at least one of the choke coils  53 ,  54 , the brush terminals  55 ,  56 , and the holder  57 . 
         [0102]    According to the embodiment, fuel used in the fuel pump is one containing a component of high electric conductivity. Alternatively, fuel used in the fuel pump may be an ordinary gasoline. 
         [0103]    It should be appreciated that while the processes of the embodiments of the present invention have been described herein as including a specific sequence of steps, further alternative embodiments including various other sequences of these steps and/or additional steps not disclosed herein are intended to be within the steps of the present invention. 
         [0104]    Various modifications and alternations may be diversely made to the above embodiments without departing from the spirit of the present invention.

Technology Classification (CPC): 5