JP2008215121A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump reducing electromagnetic noise without increasing pump size. <P>SOLUTION: An assembly 59 is provided with a choke coil 53 and a capacitor 54 constituting an LC circuit between terminals 51, 52. Thereby, electromagnetic noise occurring by electric discharge between brushes 71, 72 and a commutator 34 is reduced. Further, each of the choke coil 53, the capacitor 54, and the brushes 71, 72 are disposed in different regions in planar view of a terminal sub assembly 50, and are disposed so that each of axes are substantially parallel to each other. Therefore, the size and the projection area of the assembly 59 becomes small. Thereby, even when the assembly 59 is molded with a resin, the size of the formed terminal sub assembly 50 becomes small. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric fuel pump.

  2. Description of the Related Art Conventionally, an in-tank type pump module that houses a fuel pump inside a fuel tank is known as a fuel supply device. In the case of a fuel pump used in such a pump module, electric power is supplied from an external power source to the motor unit via a terminal. The terminal is provided in the middle of the fuel passage that connects the fuel suction portion and the fuel discharge portion of the fuel pump. Therefore, in the case of a conventional fuel pump used for fuel with low conductivity such as gasoline, the terminals are insulated from each other by the fuel flowing around. Moreover, electromagnetic noise accompanying discharge is generated between the brush and the commutator of the motor unit. Therefore, a noise reduction unit such as a choke coil or a capacitor is connected to the terminal.

  By the way, in recent years, the demand for fuel containing alcohol as an alternative fuel for gasoline is increasing. Alcohol has higher conductivity than gasoline. Therefore, when the fuel containing alcohol is fed by the fuel pump as described above, the choke coil and the capacitor connected to the terminal are exposed to highly conductive fuel. In this case, current leakage occurs between the terminals of the noise reduction unit via the fuel. When current leakage occurs, the metal material constituting the terminals of the noise reduction unit may be ionized, resulting in electrical corrosion. In view of this, for example, it has been proposed to mold a noise reduction section such as a choke coil and a capacitor with a resin so as to isolate it from the fuel (for example, see Patent Document 1).

However, when these noise reduction parts are molded with resin, it is necessary to form a resin layer on the outer peripheral side of the noise reduction part. For this reason, there is a problem that the projected area in the axial direction of the fuel pump is enlarged and the fuel pump is increased in size.
Special table 2002-544425 gazette

  Therefore, an object of the present invention is to provide a fuel pump that reduces electromagnetic noise without increasing the size of the physique.

  According to the first aspect of the present invention, when the plan view of the terminal subassembly is divided into two regions by the first virtual straight line, the brush and the noise reduction unit are arranged in different regions. Here, the first imaginary straight line is a straight line extending in the radial direction of the terminal subassembly in a plan view of the terminal subassembly viewed from the motor unit side or the side opposite to the motor unit. As described above, the brush is disposed in one region of the terminal subassembly divided by the first virtual straight line, and the noise reduction unit is disposed in the other region. Therefore, the brush and the noise reduction unit are efficiently arranged without increasing the area of the terminal subassembly in plan view, that is, the projected area. Further, the noise reduction unit reduces electromagnetic noise caused by discharge between the brush and the commutator of the motor unit. Therefore, electromagnetic noise can be reduced without increasing the size of the physique. As described above, by reducing the projected area of the terminal subassembly, even when a resin layer for insulation is provided on the outer peripheral side of the noise reduction portion, an increase in size of the body as a whole can be suppressed. Therefore, electromagnetic noise can be reduced without increasing the size of the physique, and electrochemical corrosion of the noise reduction unit can be reduced. The first imaginary straight line may or may not pass through the center of the terminal subassembly.

  In the invention described in claim 2, the noise reduction portion is provided such that the brush and the shaft are substantially parallel. Therefore, the noise reduction unit and the brush are disposed on different end portions in the radial direction of the terminal subassembly. As a result, even if the projected area of the terminal subassembly is reduced, the brush and the noise reduction portion are reduced from protruding outward from the outer edge of the terminal subassembly in the radial direction. Therefore, electromagnetic noise can be reduced without increasing the size of the physique. Thus, the projected area of the terminal subassembly is reduced by arranging the noise reduction portion and the brush so that the axes are substantially parallel. Therefore, even when a resin layer for insulation is provided on the outer peripheral side of the noise reduction portion, the overall size of the physique can be suppressed. Therefore, electromagnetic noise can be reduced without increasing the size of the physique, and electrochemical corrosion of the noise reduction unit can be reduced.

According to a third aspect of the present invention, the noise reduction unit has at least one of a choke coil and a capacitor. Therefore, the electromagnetic noise generated by the contact between the brush and the commutator of the motor unit can be reduced.
In the invention according to claim 4, when the choke coil and the capacitor are divided into two regions by the second imaginary straight line, they are arranged in different regions. Here, the second virtual straight line is divided into two regions that are perpendicular to the first virtual straight line and are different from the region where the choke coil and the capacitor are disposed, that is, the region where the brush is disposed. . Thus, when the area | region where the brush is not arrange | positioned in a terminal subassembly is divided | segmented into two area | regions, a choke coil is arrange | positioned to one area | region and a capacitor | condenser is arrange | positioned to the other area | region. Therefore, the choke coil and the capacitor are efficiently arranged. Therefore, electromagnetic noise can be reduced without increasing the size of the physique. Note that the second imaginary straight line may or may not pass through the center of the terminal subassembly.

  In the invention described in claim 5, the choke coil and the capacitor are provided so that their axes are parallel to each other. Thus, by arranging the axis of the choke coil and the axis of the capacitor in parallel, the projected area of the terminal subassembly after assembling the choke coil and the capacitor is reduced. Therefore, the physique can be reduced in size.

  In the invention described in claim 6, the noise reduction portion provided in the terminal subassembly is molded with resin. Thus, even when the terminal subassembly is exposed to a fuel containing a highly conductive component such as alcohol, the electrochemical corrosion of the noise reduction portion is reduced. Therefore, the corrosion resistance is improved and the damage of the noise reduction part can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A fuel pump according to an embodiment of the present invention is shown in FIG. The fuel pump 10 is an in-tank pump that is mounted inside a fuel tank such as a vehicle. The fuel pump 10 supplies the fuel inside the fuel tank to the engine. The fuel pump 10 includes a pump unit 20 that pressurizes the sucked fuel and a motor unit 30 that drives the pump unit 20. The motor unit 30 is a DC motor with a brush. The fuel pump 10 includes a substantially cylindrical housing 11. A plurality of permanent magnets 12 are annularly provided on the inner wall of the housing 11 in the circumferential direction. On the inner peripheral side of the permanent magnet 12, a rotor 31 of the motor unit 30 is disposed concentrically with the annular permanent magnet 12.

  The pump unit 20 includes a casing body 21, a casing cover 22, an impeller 23 that is a rotating member, and the like. The casing body 21 and the casing cover 22 form a substantially C-shaped pump flow path 24. An impeller 23 is rotatably accommodated between the casing body 21 and the casing cover 22. The casing body 21 and the casing cover 22 are formed by, for example, aluminum die casting. The casing body 21 is fixed to one end side in the axial direction of the housing 11 by press fitting. A bearing 25 is provided at the center of the casing body 21. The casing cover 22 is fixed to one end of the housing 11 by caulking or the like while being covered with the casing main body 21. A thrust bearing 26 is provided at the center of the casing cover 22. One end of the shaft 32 of the rotor 31 is rotatably supported by the bearing 25 in the radial direction, and an axial load is supported by the thrust bearing 26.

  The casing cover 22 has a fuel suction part 27. When the impeller 23 having a blade groove at the peripheral edge rotates in the pump passage 24, the fuel inside the fuel tank (not shown) is sucked into the pump passage 24 from the fuel suction portion 27. The fuel sucked into the pump passage 24 is pressurized by the rotation of the impeller 23 and is discharged to the pump chamber 13 that forms the fuel passage.

  An end cover 40, a terminal subassembly 50, and a bearing holder 60 are provided on the other end of the housing 11, that is, on the opposite side of the casing body 21 and the casing cover 22. The housing 11, the casing main body 21, the casing cover 22, and the end cover 40 constitute a case member in the claims. The terminal subassembly 50 and the bearing holder 60 are sandwiched between the end cover 40 and the housing 11. The end cover 40 is fixed to the housing 11 by caulking. The bearing holder 60 has a connection passage 61 that connects the pump chamber 13 and the fuel passage 45 of the end cover 40. As shown in FIG. 3, the bearing holder 60 accommodates brushes 71 and 72 and springs 81 and 82 as elastic members. The brushes 71 and 72 are accommodated in the accommodation chamber 62 of the bearing holder 60 so as to be reciprocally movable in the axial direction. The brushes 71 and 72 are pressed against the rotor 31 by springs 81 and 82. The brushes 71 and 72 have pigtails 711 and 721. The pigtails 711 and 721 are formed of a conductive wire. As a result, power is supplied to the brushes 71 and 72 via the pigtails 711 and 721.

  The end cover 40 has a fuel discharge part 41 and a connector 42 on the outer peripheral side of the shaft 32 as shown in FIG. The fuel discharge part 41 has a fuel passage 43 and a check valve 44. The fuel passage 43 is opened and closed by a check valve 44. When the fuel pressure inside the fuel pump 10 exceeds a predetermined value, the check valve 44 opens the fuel passage 43. The connector 42 is provided with a positive terminal 51 and a negative terminal 52. The terminal 51 and the terminal 52 constitute a terminal subassembly 50. As shown in FIGS. 1 and 3, the terminal subassembly 50 includes terminals 51 and 52 and a resin body 58. The terminals 51 and 52 are provided so as to protrude from the body 58. Further, brush terminals 55 and 56 protrude from the body 58 as shown in FIG.

  As shown in FIG. 2, the bearing holder 60 accommodates the terminal subassembly 50 between the bearing holder 60 and the end cover 40. The bearing holder 60 is accommodated on the inner peripheral side of the housing 11. The bearing holder 60 is provided with a bearing 63 at the center. Thus, the rotor 31 is rotatably supported by the bearing 63 at the end opposite to the bearing 25.

  The rotor 31 is rotatably accommodated in the housing 11. The rotor 31 is wound with a winding that forms a coil 33 on the outer periphery of the core. A commutator 34 is provided at an end portion on the end cover 40 side in the axial direction of the rotor 31. The commutator 34 is formed in a fan-like plate shape divided in a predetermined angle range. The commutator 34 contacts the brushes 71 and 72 pressed by the springs 81 and 82. Thereby, electric power is supplied from the brushes 71 and 72 to the coil 33 of the rotor 31 via the commutator 34.

  Electric power supplied from the power source (not shown) to the terminals 51 and 52 is supplied to the coil 33 of the rotor 31 via the brush terminals 55 and 56, the pigtails 711 and 721, the brushes 71 and 72, and the commutator 34. When the rotor 31 is rotated by the electric power supplied to the coil 33, the impeller 23 is rotated together with the rotor 31 and the shaft 32. Further, when the rotor 31 rotates, the commutator 34 rotates accordingly. At this time, the commutator 34 rotates while maintaining a contact state with the brushes 71 and 72. When the impeller 23 rotates together with the shaft 32 of the rotor 31, fuel is sucked into the pump flow path 24 from the fuel suction portion 27. The fuel sucked into the pump passage 24 receives kinetic energy from each blade groove of the impeller 23 and is discharged from the pump passage 24 to the pump chamber 13. The fuel discharged to the pump chamber 13 is supplied to the outside of the fuel pump 10 via the periphery of the rotor 31, the fuel passage 45 and the fuel passage 43.

Next, the structure of the terminal subassembly 50 will be described in detail.
FIG. 1 is a schematic diagram illustrating a terminal subassembly 50 according to one embodiment of the present invention. The assembly 59 shown in FIG. 1B is formed as a terminal subassembly 50 as shown in FIG. 1A by being molded with a resin corresponding to the body 58.

  As shown in FIGS. 1B and 4, the assembly 59 is configured by assembling the terminals 51 and 52, the choke coil 53, the capacitor 54, and the brush terminals 55 and 56 to an insulator holder 57. . The state shown in FIG. 1B corresponds to the assembly 59 of the terminal subassembly 50 excluding the resin molded body 58. The choke coil 53 and the capacitor 54 are provided in an insulator holder 57. The choke coil 53 and the capacitor 54 are substantially parallel in axis. Further, as shown in FIG. 3, the axes of brushes 71 and 72, choke coil 53 and capacitor 54 are substantially parallel. Thus, the projected area of the assembly 59 is reduced by arranging the axes of the choke coil 53, the capacitor 54, and the brushes 71 and 72 substantially in parallel. Thereby, when the assembly 59 is molded with resin to form the terminal subassembly 50, the size of the terminal subassembly 50 is also reduced.

  The terminal 51 is electrically connected to the brush terminal 55 as shown in FIGS. The terminal 51 and the brush terminal 55 may be integrally configured by the same member. The brush terminal 55 is connected to the brush 71 via the pigtail 711. On the other hand, the terminal 52 is electrically connected to the connection portion 521 and the connection portion 522. The terminal 52 and the connection parts 521 and 522 may be integrally configured by the same member. The connection portion 521 is connected to the terminal 51 side with the capacitor 54 interposed therebetween. The connecting portion 522 is connected to the brush terminal 56 with the choke coil 53 interposed therebetween. The brush terminal 56 is connected to the brush 72 via the pigtail 721. In this embodiment, the terminal 51 is connected to the positive side of the power source, and the terminal 52 is connected to the negative side of the power source. In addition, the terminal 51 and the terminal 52 can replace the positive electrode side and the negative electrode side naturally.

  The choke coil 53 has a core 531 and a winding 532. The core 531 is formed in a substantially cylindrical shape. A winding 532 is wound around the core 531. Winding 532 has a connecting portion 533 at one end and a connecting portion 534 at the other end. The capacitor 54 has a connection terminal 541 and a connection terminal 542. The brush terminal 55 has a connection part 551 and a connection part 552. The brush terminal 56 has a connection part 561 and a connection part 562.

  The connection part 522 of the terminal 52 and the connection part 533 of the winding 532 of the choke coil 53 are connected by heat caulking or fusing. The connecting portion 561 of the brush terminal 56 and the connecting portion 534 of the winding 532 are connected by heat caulking or fusing. As a result, the terminal 52 and the brush terminal 56 are electrically connected via the choke coil 53. The choke coil 53 is connected to the terminal 52 on the negative electrode side. The potential on the negative electrode side is lower than that on the positive electrode side. Therefore, the electrical damage is reduced by connecting the choke coil 53 to the negative electrode side.

  The connection part 551 of the brush terminal 55 and the connection terminal 541 of the capacitor 54 are connected by heat caulking or fusing. The connection portion 521 of the terminal 52 and the connection terminal 542 of the capacitor 54 are connected by heat caulking or fusing. Thus, the brush terminal 55 and the terminal 52 are electrically connected via the capacitor 54.

The connecting portion 552 of the brush terminal 55 and the pigtail 711 are connected by heat caulking or fusing. The connecting portion 562 of the brush terminal 56 and the pigtail 721 are connected by heat caulking or fusing.
Electric power is supplied to the terminals 51 and 52 from a power source. The electric power supplied to the terminals 51 and 52 is supplied to the brushes 71 and 72 via the brush terminals 55 and 56 and the pigtails 711 and 721. Electric power is supplied from the brushes 71 and 72 to the motor unit 10 via the commutator 34. At this time, electromagnetic noise accompanying the discharge is generated between the brushes 71 and 72 and the commutator 34. Therefore, in this embodiment, a capacitor 54 is connected in parallel between the terminal 51 and the terminal 52, and a choke coil 53 is connected in series on the terminal 52 side, thereby forming a so-called LC circuit. As a result, electromagnetic noise generated by the discharge between the brushes 71 and 72 and the commutator 34 is reduced.

  As shown in FIG. 4, when the terminal subassembly 50 is viewed from the side opposite to the motor unit 30, that is, in a plan view of the terminal subassembly 50, the brush terminals 55 and 56 connected to the brushes 71 and 72 and the noise reduction unit. Are arranged in a different area from the choke coil 53 and the capacitor 54. That is, in the plan view of the terminal subassembly 50, if a straight line passing through the center of the terminal subassembly 50 and extending in the radial direction is defined as the first virtual straight line L1, the first virtual straight line L1 is a two-dimensional view of the terminal subassembly 50. Divide into two areas. At this time, the brush terminals 55 and 56 are arranged in one region of the divided terminal subassembly 50, and the choke coil 53 and the capacitor 54 are arranged in the other region. As a result, the brushes 71 and 72 connected to the brush terminals 55 and 56 are arranged in a different area from the choke coil 53 and the capacitor 54. Therefore, the terminal subassembly 50 has a reduced area in plan view, that is, a projected area. The first virtual straight line L1 may pass through the center of the terminal subassembly 39 or may not pass through the center.

  Furthermore, as shown in FIG. 4, in a plan view of the terminal subassembly 50, a straight line that passes through the center of the terminal subassembly 50 and the region where the choke coil 53 and the capacitor 54 are disposed and is perpendicular to the first virtual straight line L <b> 1 is obtained. This is defined as a second virtual straight line L2. The second virtual straight line L2 further divides the region on the choke coil 53 and capacitor 54 side divided by the first virtual straight line L1 into two. At this time, the choke coil 53 and the capacitor 54 constituting the noise reduction unit are arranged in different regions. That is, the choke coil 53 is disposed in one of the regions divided by the second virtual straight line L2, and the capacitor 54 is disposed in the other region. Therefore, even when the noise reduction unit is configured by an LC circuit, the projected area of the terminal subassembly 50 is reduced. The second virtual straight line L2 may pass through the center of the terminal subassembly 50 or may not pass through the center.

Next, the operation of the fuel pump 10 configured as described above will be briefly described with reference to FIG.
When electric power is supplied to the terminals 51 and 52 from the outside, the electric power is supplied from the terminals 51 and 52 to the commutator 34 via the brush terminals 55 and 56, the pigtails 711 and 721, and the brushes 71 and 72. Thereby, the rotor 31 of the motor unit 30 rotates, and the impeller 23 rotates together with the shaft 32 of the rotor 31.

  As the impeller 23 rotates, fuel in a fuel tank (not shown) is sucked from the fuel suction portion 27. The fuel sucked from the fuel suction part 27 is pressurized by the rotation of the impeller 23 in the pump flow path 24. Then, the pressurized fuel is discharged to the pump chamber 13 of the motor unit 10. The fuel discharged to the pump chamber 13 flows into the fuel passage 45 and the fuel passage 43 of the end cover 40 through the fuel passage and the connection passage 61 formed on the outer peripheral side of the rotor 31 inside the housing 11. The fuel flowing into the fuel passage 45 inside the end cover 40 pushes up the check valve 44 and is fed from the fuel discharge portion 41 to the internal combustion engine of the vehicle.

  As described above, in this embodiment, the capacitor 54 is connected in parallel between the terminal 51 and the terminal 52. A choke coil 53 is connected to the terminal 52 in series. Thereby, an LC circuit is configured, and electromagnetic noise generated by the discharge between the brushes 71 and 72 and the commutator 34 is reduced. Further, in the assembly 59 constituting the terminal subassembly 50, the choke coil 53, the capacitor 54, and the brushes 71 and 72 are arranged in different regions divided by the first virtual straight line L1 in a plan view of the terminal subassembly 50. ing. Further, the choke coil 53 and the capacitor 54 are also arranged in different regions divided by the second virtual straight line L2 in a plan view of the terminal subassembly 50. Further, the assembly 59 is arranged such that the axes of the choke coil 53, the capacitor 54, and the brushes 71 and 72 are substantially parallel to each other. Therefore, the physique and projected area of the assembly 59 are reduced. Thereby, even if the assembly 59 is molded with resin, the size of the terminal subassembly 50 is not increased. Therefore, electromagnetic noise can be reduced without increasing the size of the physique.

  In the present embodiment, the choke coil 53 and the capacitor 54 provided in the terminal subassembly 50 are molded with resin. Therefore, even if the fuel flows around the terminal subassembly 50, the choke coil 53 and the capacitor 54 are not exposed to the fuel. Thereby, even when a fuel containing a highly conductive component such as alcohol is used, electrochemical corrosion of the metal portions of the choke coil 53 and the capacitor 54 can be reduced. Accordingly, the corrosion resistance is enhanced, and damage to the choke coil 53 and the capacitor 54 can be reduced.

In this embodiment, the target fuel is a fuel containing a highly conductive component such as alcohol. However, the target fuel may be ordinary gasoline.
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

It is a figure which shows the fuel pump by one Embodiment of this invention, (A) is the schematic which shows a terminal subassembly, (B) is the schematic which shows an assembly. 1 is a cross-sectional view schematically showing a fuel pump according to an embodiment of the present invention. (A) is the schematic which shows the assembly | attachment of the end cover, terminal subassembly, brush, and bearing holder of the fuel pump by one Embodiment of this invention, (B) is the figure seen from the arrow B direction of (A) . The figure which looked at the terminal subassembly of the fuel pump by one Embodiment of this invention from the arrow IV direction of FIG. 1 (B).

Explanation of symbols

  10: Fuel pump, 11: Housing (case member), 20: Pump part, 21: Casing body (case member), 22: Casing cover (case member), 27: Fuel intake part, 30: Motor part, 34: Rectification 40, end cover (case member), 41: fuel discharge section, 43, 45: fuel passage, 50: terminal subassembly, 51, 52: terminal, 53: choke coil (noise reduction section), 54: capacitor ( Noise reduction unit), 71, 72: Brush

Claims (6)

A case member having a fuel passage therein and having a fuel intake part and a fuel discharge part for fuel;
A pump unit disposed in the fuel passage and sucking fuel from the fuel suction unit and pumping the fuel toward the fuel discharge unit;
A motor unit that is disposed inside the case member and drives the pump unit;
A terminal to which power to be a driving source of the motor unit is supplied from the outside;
A terminal subassembly disposed within the case member and having the terminal;
A brush that contacts the commutator of the motor unit and supplies power from the terminal to the motor unit;
The brush is disposed when the terminal subassembly is connected to the terminal and divided into two regions by a first imaginary straight line extending in a radial direction of the terminal subassembly in a plan view. A noise reduction unit that is disposed on a region side different from the region where the noise is present and reduces electromagnetic noise generated between the commutator and the brush;
With fuel pump.   The fuel pump according to claim 1, wherein the noise reduction unit is provided substantially parallel to an axis of the brush.   The fuel pump according to claim 1, wherein the noise reduction unit includes at least one of a choke coil and a capacitor.   The choke coil and the capacitor are arranged in different areas when an area different from the area where the brush is arranged in a second virtual line perpendicular to the first virtual line is further divided into two areas. The fuel pump according to claim 3.   The fuel pump according to claim 3 or 4, wherein the choke coil and the capacitor are provided so that their axes are substantially parallel to each other.   The fuel pump according to any one of claims 1 to 5, wherein the noise reduction unit is molded of resin.

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