JP2006325284A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fuel pump comprising a pump section, a motor section, and a delivery section, in which deterioration in conductivity due to oil film formed between a commutator and a brush is prevented, without having to increase the size. <P>SOLUTION: A brush 9, abutting against a commutator segment 7b constituting the surface of a disk-like commutator 7 provided integrally with the motor shaft 3 at a motor section M, has a rectangular profile elongated in the axial direction of the motor shaft 3. Among four corners 9d in the circumferential direction formed by four side pieces 9c of the brush 9, a pair of corners 9d located in the diagonal direction are arranged along the rotational direction of the commutator 7, and the corner facing the fuel flow serves as a fuel straightening section 9e, which pushes away the fuel in a manner of cutting, accompanying the motor section M rotation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a fuel pump disposed in a fuel tank of a vehicle or the like.

  In general, in a fuel pump including a pump unit, a motor unit, and a discharge unit that discharges fuel, a commutator is integrally provided on the motor shaft of the motor unit, and the tip of the brush is elastically formed on the surface of the commutator. Some are configured to contact the

In such a case, the brush is formed long in the axial direction of the motor shaft and accommodated in the discharge portion, and the tip of the brush is elastically formed on the surface of a disc-shaped commutator integrally provided on the motor shaft. It may be configured to be slidably contacted. As such, the commutator piece that makes contact with the brush of the commutator has a fan shape, while the contact surface with the commutator at the tip of the brush has a shape of the commutator piece. And a configuration in which the longitudinal base end portion of the brush is urged by a coil machine is proposed.
JP 63-272994 A

  By the way, in the fuel pump, the fuel sucked from the pump portion flows into the motor portion and is discharged from the discharge portion, and the inside of the fuel pump is always filled with fuel, and the tip of the brush The fuel is also immersed in the contact portion between the part and the commutator. On the other hand, the conventional brush is arranged in such a positional relationship that one side piece of the brush is parallel to the side piece of the rotating commutator piece, and the side piece of the rotating commutator piece is Thus, the surface that contacts in advance is a contact surface that is long in the radial direction. Therefore, the side piece of the brush becomes an obstacle to the flow of fuel accompanying rotation of the commutator, a predetermined amount of fuel enters between the brush tip and the commutator surface, and the oil film becomes thick, so-called road surface and tire It becomes like a hydroplaning phenomenon that occurs between the brush tip and the commutator surface, and the electrical resistance (contact resistance) between the brush tip and the commutator surface increases, resulting in motor efficiency. There is a problem that it falls. In order to cope with this, it is conceivable to increase the urging force of the coil ammunition, but if this is done, the fuel pump will become larger, and another problem that the miniaturization that is the original purpose will be impaired. There is a problem to be solved by the present invention.

SUMMARY OF THE INVENTION The present invention was created in view of the above-described circumstances to solve these problems, and the invention of claim 1 includes a pump unit, a motor unit, and a discharge unit, and includes a motor. In the fuel pump in which the brush is elastically contacted with a commutator provided integrally with the motor shaft of the part, the brush is formed with a fuel rectifier that pushes away the fuel.
According to a second aspect of the present invention, in the first aspect, the fuel rectifying unit is configured by a protrusion that protrudes in a direction opposite to the rotation direction of the motor shaft.
According to a third aspect of the present invention, in the second aspect, the fuel rectifying unit has a protruding end formed in a square shape.
According to a fourth aspect of the present invention, in any one of the first, second, and third aspects, the fuel rectifying unit is configured by one corner portion of a brush formed in a prismatic shape.

By making it the invention of Claim 1 or 2, the fall of the electroconductive state by an oil film can be avoided, without impairing compactization.
By setting it as invention of Claim 3, a brush can push away the flow of fuel efficiently, and it can be set as a fuel pump with high motor efficiency.
By setting it as invention of Claim 4, a highly versatile brush can be used as it is, and cost reduction can be achieved.

Next, embodiments of the present invention will be described with reference to the drawings.
In the drawings, reference numeral 1 denotes an in-tank type fuel pump. The fuel pump 1 includes a pump part P, a motor part M, and a fuel discharge part F from one end, and constitutes the motor part M. One end portion (lower end portion in FIG. 1) of the motor shaft 3 housed in the cylindrical motor housing 2 is rotatably supported by the pump housing 4 constituting the pump portion P, and one end of the motor shaft three-bearing portion. An impeller (not shown) accommodated in the pump housing 4 is integrally provided on the side, and the impeller rotates as the motor shaft 3 rotates to suck the fuel in the fuel tank into the fuel pump 1. Is set.

An armature core 5 configured by laminating a plurality of core materials 5 a is integrally fitted on the motor shaft 3, and a plurality of coils 6 are wound around the armature core 5 in the circumferential direction. It is disguised. Further, a disc-shaped commutator 7 is integrally fitted and fixed to the other end (upper end) of the motor shaft 3, thereby forming a rotor R in the motor unit M.
Here, the commutator 7 is a circumference formed by a resin boss portion 7a fitted on the motor shaft 3 and a conductive member insert-molded on the disk surface on the other axial end side of the boss portion 7a. A commutator piece 7b in a plurality of directions is provided, and a riser piece 7c that is electrically connected to each commutator piece 7b and is insert-molded in a state of extending to the outer diameter side. Incidentally, as for the commutator piece 7b of this Embodiment, the fan-shaped thing is provided in 6 ring shape in the circumference direction. And the winding start end part and winding end part of the some coil 6 wound by the said armature core 5 are set so that each may be electrically connected to the riser piece 7c located in the circumference direction predetermined place. .
The rotor R configured as described above is set so as to be accommodated in the motor housing 2 in a state of being close to the pair of permanent magnets 2 a fixed to the inner peripheral surface of the motor housing 2. Note that the cylinder end portion on one end side of the motor housing 2 is covered with the pump housing 4 in a sealing manner.

  On the other hand, a discharge portion housing 8 constituting the discharge portion F is disposed at the other end portion of the motor housing 2, and the discharge portion housing 8 seals the cylindrical end portion on the other end side of the motor housing 2. It is comprised so that it may be covered with. A concave hole-shaped bearing portion 8 a that rotatably supports the other end protruding from the commutator 7 of the motor shaft 3 is formed at the center of the discharge portion housing 8. Further, the discharge portion housing 8 is provided with a pair of axially long through holes 8b constituting a brush holder in the circumferential direction, and the through holes 8b are rectangular (cuboid) brushes that are long in the axial direction. 9 is accommodated so as to be slidable in the axial direction in a posture described later. A receiving member 8c is integrally provided at the hole end on the other end side in the axial direction of the through hole 8b in which the brush 9 is accommodated, and a coil elastic member is provided between the receiving member 8c and the other end side surface 9a of the brush 9. As a result, the brush 9 projects from one end side of the through-hole 8b under the urging force of the coil bullet machine 10, and one end side surface 9b (brush tip) of the brush 9 is The commutator piece 7b (commutator surface) of the commutator 7 is set so as to be slidably pressed. When the brush 9 is supplied from an external power source, the coil 6 is supplied with power from the brush 9 via the commutator piece 7b and the riser 7c to be excited, whereby the rotor R is moved to the motor housing 2. It is set so as to receive and rotate the magnetic pole formed in the cylinder.

And this invention is implemented in the sliding contact site | part of the one end side surface 9b of the said brush 9, and the commutator piece 7b.
That is, the brush 9 has a rectangular parallelepiped shape as described above, and is formed by including the four side pieces 9c that are long in the axial direction, whereby four corners in the circumferential direction with respect to the longitudinal axis center of the brush 9 are formed. A portion 9d is formed, and each corner portion 9d is formed in a sharp angular shape (a prismatic shape) with a tip at an angle of 90 degrees. The brush 9 is not disposed in a positional relationship in which any of the four side pieces 9c is parallel to the side piece 7d on the rotational direction front side of the commutator piece 7b. As shown in FIG. 2, two corner portions 10d located in the diagonal direction among the four corner portions 9d are arranged in a posture substantially along the rotation locus. When the commutator 7 rotates in a preset direction (one direction), the corner portion 9e of the brush 9 facing the rear side (reverse side) in the rotation direction of the commutator 7 corresponds to the fuel rectifying unit of the present invention. The corner portion (fuel rectifying portion) 9e is set so as to come into sliding contact with the side piece 7d on the front side in the rotational direction of an arbitrary commutator piece 7b rotating. The brush 9 rectifies the fuel in a state in which the fuel rectifying unit 9e pushes away the fuel in the vicinity of the commutator piece 7b, that is, in a state of tearing, by the fuel rectifying unit 9e slidably contacting the commutator 7 in advance. It is set to come into sliding contact (contact) with the commutator piece 7b by further relative rotation. As a result, when the fuel pump 1 is driven, the flow of the fuel accompanying the rotation of the commutator 7 may be rectified so that the corner portion (fuel rectifying portion) 9e of the brush 9 is pushed away. As a result, it is possible to reduce the occurrence of an oil film due to fuel entering between the commutator piece 7b, and to reduce the electrical resistance (contact resistance) between them. In this way, it is configured to maintain a good conductive state.
Further, in the brush 9 of the present embodiment, the corner portion (fuel rectifying portion) 9e is also rotated relative to the portion projecting from the through hole (brush holder) 8b in a prismatic shape, so that the projecting portion However, the resistance received by the flow of fuel accompanying the rotation of the commutator 7 is reduced (can reduce the obstacle to the flow of fuel by the brush 9), and the brush 9 can be prevented from rising. Yes.

  In the present embodiment configured as described, in the in-tank type fuel pump 1, the fuel is immersed in the fuel pump 1, and the motor part M is driven to drive one end side surface 9 b of the brush 9 that is long in the axial direction. It is assumed that fuel accumulates between the disk-shaped commutator 7 and the commutator piece 7b of the disc-shaped commutator 7, and an oil film that impairs the conductive state between these is formed. In this case, the brush 9 Of the four rectangular parallelepiped corner portions 9d, a corner portion (fuel rectifying portion) 9e located on the opposite side of the commutator 7 in the rotational direction abuts (contacts) the rotating commutator piece 7b in advance. It has become. As a result, the corner portion (fuel rectifying portion) 9e of the brush 9 that rotates relative to the commutator piece 7b rotates relative to the commutator piece 7b in a state where the fuel in the vicinity of the commutator piece 7b pushes away (cuts) in advance. The brush 9 does not become an obstacle to the flow of fuel accompanying the rotation, and it is possible to prevent the oil film between the commutator 7 and the brush 9 from becoming thicker, whereby the brush 9 and the commutator 7 In this case, the electrical resistance is reduced, the conductive state is improved, and the fuel pump 1 with high motor efficiency can be obtained. As a result, it is possible to provide an excellent fuel pump 1 in which the conductive state is well maintained while it is not necessary to increase the size of the discharge portion F in order to increase the urging force of the brush 9.

Moreover, in this case, the shape of the brush 9 is a rectangular parallelepiped shape that is long in the axial direction, and this is simply supported by the through-hole 8b of the discharge portion casing 8 in a posture rotated around a predetermined longitudinal axis. With this simple configuration, the fuel on the surface of the commutator 7 can be efficiently removed, so that the general-purpose brush 9 can be used as it is without preparing a special brush. A pump can be provided at low cost.
In this case, the brush 9 has a prismatic shape, and the brush corner portion 9e precedes and rotates relative to the portion protruding between the through hole (brush holder) 8b and the commutator piece 7b, The resistance acting on the brush 9 from the fuel soaking the part can be reduced, and the brush 9 can be further prevented from being lifted, and the motor efficiency can be further improved.

Of course, the present invention is not limited to the above-described embodiment, and a second embodiment shown in FIG. 5B can also be used.
In the brush 12 of the second embodiment, a corner portion (fuel removal portion) 12b formed between the four side pieces 12a is formed in an R shape. Even in this case, the fuel on the commutator can be removed by the corner portion 12b.

Moreover, it can also comprise like 3rd Embodiment shown in FIG.5 (C).
This uses the same brush 12 as in the second embodiment, and of the R-shaped corner portion 12b, the bisector L of the corner portion 12c on the opposite side of the rotational direction of the commutator 7 is Of the side pieces in the radial direction of the fan-shaped commutator piece 7b, the commutator piece 7b is arranged in a positional relationship orthogonal to the side piece 7d located on the front side in the rotational direction. It is configured to slidably contact with the piece 7d in an orthogonal shape. Even in this case, the removal of fuel on the commutator by the corner portion 12c can be effectively realized.

  On the other hand, since the electric motor of the fuel pump is generally configured to rotate in one direction, the fuel excluding portion of the brush in the fuel pump provided with the electric motor rotating in one direction may be provided in one place. As such a shape, as shown in the fourth embodiment of FIG. 5D, a triangular fuel exclusion portion 13a may be formed only on one side piece of the rectangular brush 13. . Further, as shown in the fifth embodiment in FIG. 5E, a triangular fuel exclusion portion 14a may be formed at the other end portion of one side piece of the rectangular brush 14. . Further, as in the sixth embodiment of FIG. 5 (F), one side piece of the rectangular brush 15 has a tip shape in which the ship traveling direction tip side portion is imaged, that is, a pair of triangular sides. It is good also as a structure which forms the fuel exclusion part 15a of a shape where a piece bulges to the outer diameter side.

Further, as in the seventh embodiment of FIG. 6A, a fuel exclusion portion 16a that is a semicircular protrusion is formed on one side piece of the rectangular brush 16, FIG. As in the eighth embodiment of B), a triangular brush 17 is used, and one corner portion of the brush 17 is a fuel excluding portion 17a, which is the same as that of the ninth embodiment of FIG. Thus, the fuel exclusion part 18a which is a protrusion which is biased toward the inner diameter side (outer diameter side) can be formed on one side piece of the rectangular brush 18.
Thus, the shape of the brush may be any shape that protrudes in the direction opposite to the rotation direction of the motor unit and can efficiently push away (rectify) the fuel in the vicinity of the commutator.
Further, the shape of the commutator is not limited to a disk shape as in the above-described embodiment, and may be a commutator in which a commutator piece is provided on a cylindrical outer peripheral surface.

It is a partial cross section front view of a fuel pump. 2A and 2B are a front view and a plan view, respectively, illustrating a state in which an armature core and a commutator are mounted on the armature shaft. 3A and 3B are a plan view and a partially cutaway front view of the discharge unit housing, respectively. 4A, 4 </ b> B, 4 </ b> C, and 4 </ b> D are a plan view of the commutator, a cross-sectional view taken along line XX in FIG. 4A, a bottom view, and a front view, respectively. FIG. 5A is a pattern diagram for explaining the positional relationship between the commutator piece and the brush, FIG. 5B is a pattern diagram for explaining the positional relationship between the commutator piece and the brush in the second embodiment, and FIG. Is a pattern diagram for explaining the positional relationship between the commutator piece and the brush in the third embodiment, FIG. 5D is a perspective view of the brush in the fourth embodiment, and FIG. 5E is the fifth embodiment. FIG. 5F is a perspective view of the brush according to the sixth embodiment. 6A, 6B, and 6C are plan views of the brushes in the seventh, eighth, and ninth embodiments, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel pump F Discharge part 2 Motor housing 3 Motor shaft 4 Pump housing 5 Armature core 7 Commutator 7b Commutator piece 8 Discharge part housing 8b Through-hole 9 Brush 9c Four side piece 9d Corner part 9e Fuel rectification part

Claims (4)

  A fuel pump comprising a pump unit, a motor unit, and a discharge unit, wherein a brush is elastically contacted with a commutator integrally provided on a motor shaft of the motor unit. The fuel pump in which the part is formed.   The fuel pump according to claim 1, wherein the fuel rectification unit is configured by a protrusion protruding in a direction opposite to a rotation direction of the motor shaft.   3. The fuel pump according to claim 2, wherein the fuel rectifying unit has a protruding end formed in a square shape.   4. The fuel pump according to claim 1, wherein the fuel rectifying unit is configured by one corner portion of a brush formed in a prismatic shape. 5.

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