JP2006063953A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump capable of preventing corrosion of permanent magnet by fuel. <P>SOLUTION: The fuel pump is provided with an impeller, a motor 14 for driving the impeller, a housing 12 storing the motor 14. Fuel compressed by rotation of the impeller passes through an inside of the housing 12 and is discharged to an outside of the housing 12. The motor 14 includes a rotor 21 and a stator fixed on the housing 12. A coil is provided on one of the rotor 21 and the stator. The permanent magnets 25, 26 are provided on another of the rotor 21 and the stator. The fuel pump includes a cover 23 for separating the permanent magnets 25, 26 and a fuel passage of the housing 12 with covering at least a part of the permanent magnets 25, 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel pump. Specifically, the present invention relates to a motor that drives a fuel pump.

2. Description of the Related Art A fuel pump that is disposed in a fuel tank of an automobile or the like and boosts and discharges sucked fuel is known. The fuel pump includes an impeller, an impeller driving motor, and a housing that houses the motor. The motor has a rotor and a stator fixed to the housing. A coil is provided on one of the rotor and the stator. A permanent magnet is provided on the other of the rotor and the stator.
The fuel pressurized by the impeller is discharged after passing through the housing. For this reason, the permanent magnet of the motor is exposed to the fuel passing through the housing. In order to prevent the permanent magnet from being corroded by the fuel, a technique for applying a protective film to the surface of the permanent magnet is known (for example, Patent Document 1).

JP 2004-124122 A

The fuel contains fine foreign matter. The fuel passing through the housing flows violently as the motor rotor rotates. When the fuel flows violently, the foreign matter contained in it moves violently and collides with the permanent magnet. For this reason, even if the protective film is applied to the permanent magnet, the protective film may be damaged by the foreign matter contained in the fuel, and the permanent magnet may be corroded.
The present invention has been made to solve such a problem, and an object thereof is to provide a fuel pump capable of preventing corrosion of a permanent magnet by fuel.

The fuel pump of the present invention includes an impeller, a motor for driving the impeller, and a housing that houses the motor. Due to the rotation of the impeller, the pressurized fuel passes through the housing and is discharged outside the housing. The motor has a rotor and a stator fixed to the housing. A coil is provided on one of the rotor and the stator. A permanent magnet is provided on the other of the rotor and the stator. The fuel pump has a cover that isolates the permanent magnet and the fuel passage of the housing while covering at least a part of the permanent magnet.
In the fuel pump motor, the permanent magnet and the fuel passage of the housing are isolated by a cover that covers at least a part of the permanent magnet. For this reason, the foreign material in fuel does not collide with a permanent magnet. Therefore, corrosion of the permanent magnet due to the fuel can be prevented.

In the fuel pump, the permanent magnet is preferably attached via a cover.
When the permanent magnet is attached via the cover, there is no need to separately provide a member for fixing the permanent magnet.

In the above fuel pump, a stator is arranged outside the rotor, a permanent magnet is provided on the stator, the housing is formed in a substantially cylindrical shape, and a first body in which a fuel suction hole is provided at one end of the housing. It is preferable that a second body provided with a fuel discharge hole is attached to the other end of the housing, and the cover is sandwiched between the first body and the second body.
In this fuel pump, the cover is sandwiched between the first body and the second body. For this reason, the cover is mounted in a stable state.

In the above fuel pump, a stator is disposed outside the rotor, a permanent magnet is provided on the stator, the housing and the cover are formed in a substantially cylindrical shape, and the cover outer peripheral surface is opposed to the housing inner peripheral surface, The cover outer peripheral surface is formed with a recess that makes a round in the circumferential direction, and the permanent magnet is preferably formed in an annular shape and disposed in the recess.
According to this fuel pump, the permanent magnet is separated from the fuel passage by being disposed in the concave portion formed in the circumferential direction formed on the outer peripheral surface of the cover.

In the above fuel pump, a stator is disposed outside the rotor, a permanent magnet is provided on the stator, the housing and the cover are formed in a substantially cylindrical shape, and the cover outer peripheral surface is opposed to the housing inner peripheral surface, A plurality of outer peripheral recesses are formed along the circumferential direction on the outer peripheral surface of the cover, and at least two permanent magnets are provided, each of which is disposed in each outer recess, and between adjacent outer recesses. It is preferable that an inner peripheral concave portion extending in the cover axial direction is formed in the cover inner peripheral surface region.
When the inner peripheral side recess extending in the cover axial direction is formed in the cover inner peripheral surface region, the fluid resistance of the fuel passing through the housing is lowered. Therefore, the pump performance is improved.

In the fuel pump described above, it is preferable that at least one side of the inner peripheral side recess in the cross-section perpendicular to the cover axis is curved.
If at least one side portion of the inner peripheral side recess in the direction perpendicular to the cover axis is curved, the fluid resistance of the fuel passing through the housing is further reduced.

An embodiment according to a fuel pump of the present invention will be described with reference to the drawings. The fuel pump 10 is used in a state where it is immersed in the fuel in the fuel tank. Note that the top and bottom in FIG. 1 correspond to the top and bottom of the fuel pump 10 disposed in the fuel tank.
As shown in FIG. 1, the fuel pump 10 includes a housing 12, a motor 14, a lower body 15, an impeller 17, and an upper body 18. The housing 12 is formed in a cylindrical shape and accommodates the motor 14. The lower body 15 is a casing for forming a pump chamber. The lower body 15 includes two upper and lower bodies, and is fixed to the lower portion of the housing 12. The lower body 15 is provided with a fuel suction hole 16. The impeller 17 has a disk shape and is rotatably accommodated in the lower body 15. The upper body 18 is fixed to the upper part of the housing 12. The upper body 18 is provided with an electrical connector 19 and a fuel discharge hole 20. Electric power is supplied to the electrical connector 19 from the outside.

As shown in FIG. 2, the motor 14 includes a rotor 21, a shaft 22, a first magnet 25, a second magnet 26, and a cover 23. The shaft 22 passes through the rotor 21. The first magnet 25 and the second magnet 26 are permanent magnets and function as a stator of the motor 14. The upper body 18 rotatably supports the upper portion of the shaft 22. The lower body 15 rotatably supports the lower portion of the shaft 22. Although not shown in FIG. 2, an impeller 17 is attached to the lower end portion of the shaft 22. As shown in FIG. 3, the magnets 25 and 26 are formed in a tile shape (partial arc shape). For the magnets 25 and 26, for example, rare earth magnets are used. A protective coating (for example, a resin coating such as polyimide) can be applied to the surfaces of the magnets 25 and 26. Since the protective coating is applied, the corrosion resistance of the magnets 25 and 26 is improved. The cover 23 is made of resin (for example, polyoxymethylene (POM) or polyphenylene sulfide (PPS), and two outer peripheral recesses 34 are formed on the outer peripheral surface. The material and thickness of the cover 23 are as follows. It is preferable to consider so as to increase the magnetic permeability, and the magnets 25 and 26 are covered by the cover 23 on the inner peripheral surface, the upper end surface, the lower end surface, and both side end surfaces in a state of being accommodated in the outer peripheral recess 34. The outer peripheral surfaces of the magnets 25 and 26 are in contact with the inner peripheral surface of the housing 12. The cover 23 is formed with an inner peripheral recess 35 extending in the vertical direction. The cover 23 and the housing 12 are fixed by, for example, adhesion, mechanical fitting, etc. The magnet 12 is attached to the housing 12. , To fix the 26 directly, it is also possible to attach a cover 23 to the magnet 25.
The entire surfaces of the magnets 25 and 26 can be covered with the cover 23.
The rotor 21 is provided with a plurality of rotor yokes (not shown), and a coil (not shown) is wound around each rotor yoke. When electric power is supplied to the coil via the electrical connector 19, the rotor 21 of the motor 14 rotates by the magnetic action. When the rotor 21 rotates, the impeller 17 rotates accordingly. When the impeller 17 rotates, fuel is sucked from the fuel suction hole 16 of the lower body 15. The fuel sucked from the fuel suction hole 16 is pressurized by the impeller 17, flows through the housing 12, and is discharged from the fuel discharge hole 20 of the upper body 18.

The fuel whose pressure is increased by the rotation of the impeller 17 passes through a fuel passage 30 formed between the cover 23 and the rotor 14. In FIG. 2, illustration of fuel flow paths formed in the upper body 18 and the lower body 15 that allow the fuel to pass upward is omitted.
Foreign matter may be mixed in the fuel. The fuel passes through the fuel passage 30 while flowing vigorously as the rotor 21 rotates. When the fuel flows violently, foreign substances move violently in the fuel passage 30 along with it. Even if the foreign matter moves violently in the fuel passage 30, the cover 23 is provided, so that the foreign matter is prevented from colliding with the magnets 25 and 26. If the foreign matter is prevented from colliding with the magnets 25 and 26, the magnets 25 and 26 can be prevented from corroding due to the protective film being damaged. Further, even if the magnets 25 and 26 are not coated with a protective film, the surfaces of the magnets 25 and 26 are prevented from being scratched, so that corrosion can be prevented from proceeding from the scratches. it can.
Further, when the cover 23 is provided, when the rotor 21 is assembled to the housing 12, the rotor 21 and the magnets 25 and 26 come into contact with each other, and the protective coating of the magnets 25 and 26 and the magnets 25 and 26 themselves are damaged. It is prevented from sticking.

As shown in FIG. 4, the cover 23 may be shaped to be sandwiched between the upper body 18 and the lower body 15. If comprised in this way, the cover 23 will be mounted | worn in the more stable state.
As shown in FIG. 5, the side part 35a of the inner peripheral side recessed part 35 can also be curved. When the inner peripheral recess 35 is formed in this way, the fluid resistance (pressure loss) of the fuel passing through the fuel passage 30 is reduced. When the fluid resistance is reduced, the pump performance of the fuel pump 10 is improved.
FIG. 6 illustrates a form in which the cover 23 covers the annular magnet 32.
In addition, in the cover 23 which covers the tile-like magnets 25 and 26 as shown in FIGS. 3 and 5, the inner peripheral recess 35 may not be formed. If the inner peripheral recess 35 is not formed, the inner peripheral surface of the cover 23 becomes smooth. Therefore, by appropriately securing the distance between the cover 23 and the rotor 21, the fluid resistance of the fuel passing through the fuel passage 30 can be reduced. can do.

  The technique described in the present embodiment can also be applied to a fuel pump in which a rotor having a magnet rotates around a stator provided with a coil. In this case, the cover rotates with the magnet.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The side view of a fuel pump. The fragmentary sectional view of a fuel pump. III-III sectional view taken on the line of FIG. The fragmentary sectional view of a fuel pump. FIG. 3 is a partial cross-sectional view in the direction perpendicular to the axis of the fuel pump. Same as above.

Explanation of symbols

10: Fuel pump 12: Housing 14: Motor 15: Lower body 16: Fuel intake hole 17: Impeller 18: Upper body 19: Electric connector 20: Fuel discharge hole 21: Rotor 22: Shaft 23: Cover 25: First magnet 26: Second magnet 30: Fuel passage 32: Magnet 34: Outer peripheral recess 35: Inner peripheral recess 35a: Side

Claims (6)

Impeller,
A motor for driving the impeller;
A housing for housing the motor,
Due to the rotation of the impeller, the pressurized fuel passes through the housing and is discharged outside the housing.
The motor has a rotor and a stator fixed to the housing,
A coil is provided on one of the rotor and the stator, and a permanent magnet is provided on the other of the rotor and the stator,
A fuel pump comprising a cover for isolating the permanent magnet from the fuel passage of the housing in a state of covering at least a part of the permanent magnet.   The fuel pump according to claim 1, wherein the permanent magnet is attached via a cover. A stator is placed outside the rotor,
A permanent magnet is provided on the stator,
The housing is formed in a substantially cylindrical shape,
A first body provided with a fuel suction hole is attached to one end of the housing,
A second body provided with a fuel discharge hole is attached to the other end of the housing,
The fuel pump according to claim 1, wherein the cover is sandwiched between the first body and the second body. A stator is placed outside the rotor,
A permanent magnet is provided on the stator,
The housing and cover are formed in a substantially cylindrical shape,
The outer peripheral surface of the cover faces the inner peripheral surface of the housing,
On the outer peripheral surface of the cover, a recess that makes a round in the circumferential direction is formed,
The fuel pump according to claim 1, wherein the permanent magnet is formed in an annular shape and disposed in the recess. A stator is placed outside the rotor,
A permanent magnet is provided on the stator,
The housing and cover are formed in a substantially cylindrical shape,
The outer peripheral surface of the cover faces the inner peripheral surface of the housing,
A plurality of outer peripheral recesses are formed along the circumferential direction on the outer peripheral surface of the cover,
At least two permanent magnets are provided, and each permanent magnet is disposed in each outer peripheral recess,
3. The fuel pump according to claim 1, wherein an inner peripheral concave portion extending in a cover axial direction is formed in a cover inner peripheral surface region between adjacent outer peripheral concave portions.   6. The fuel pump according to claim 5, wherein at least one side portion of the inner peripheral side concave portion in the direction perpendicular to the cover axis is curved.

Images