JP2007187145A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump preventing accumulation of fuel and foreign matter in a bearing hole of a fuel delivery side provided with a bearing of a rotary shaft of a rotor. <P>SOLUTION: A motor part 13 is a brushless motor, and sucked-in fuel is pressurized by rotating an impeller 24 of a pump part 12 rotatively driven by the motor part 13. An insulating resin material 4 is molded to cover a coil 42, and it integrally forms an end cover 50 covering an end in an opposite side of the pump part 12 with respect to a stator core 30. In the end cover 50, the bearing hole 52 for bearing a shaft 72 is formed in a center part. The bearing hole 52 directly bears the shaft 72, and a bottom is blocked. In the end cover 50, a delivery passage 206 is formed, decentered from the bearing hole 52. The delivery passage 206 is formed to linearly pierce the end cover 50 in an axial direction, and it is directly overlapped and communicated with the bearing hole 52. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel pump.

  2. Description of the Related Art There is known a fuel pump that drives a pump unit by a rotational driving force of a motor unit and discharges fuel boosted by the pump unit (see, for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, a cover covers an axial end portion side opposite to a pump portion of a motor portion using a brushless motor, and a discharge port for discharging fuel is formed in the cover. The cover is provided with a bearing for bearing the rotating shaft of the rotor of the motor unit.

  However, in Patent Documents 1 and 2, the bottom portion of the bearing hole of the cover provided with the bearing is closed, and the fuel stays in the bearing hole. As a result, the fuel staying in the bearing hole may deteriorate, and the rotating shaft may be corroded by the deteriorated fuel. Further, for example, foreign matter such as abrasion powder generated in the fuel pump may stay in the bearing hole, and the foreign matter may be caught in the sliding portion between the rotating shaft and the bearing.

JP 2005-110477 A JP 2005-110478 A

  The present invention has been made to solve the above-described problem, and provides a fuel pump that prevents fuel and foreign matter from staying in a fuel discharge side bearing hole provided with a bearing for a rotating shaft of a rotor. Objective.

  In the invention described in claims 1 to 7, a cover is installed on the axial end side opposite to the pump portion of the rotating shaft of the rotor and covers the stator and the rotor. The cover is formed with a discharge passage for discharging the fuel whose pressure has been increased by the pump unit, and the rotating shaft is supported in a bearing hole provided in the cover. Here, the bottom of the bearing hole of the cover is closed, but the communication path is in communication with the discharge passage and the bearing hole, so fuel and foreign matter inside the bearing hole are discharged from the bearing hole through the communication path. It flows into the passage. As a result, since new fuel flows through the sliding portion between the bearing hole and the rotating shaft of the rotor, deterioration of the fuel in the bearing hole can be prevented, and corrosion of the rotating shaft due to the deteriorated fuel can be prevented. Further, since foreign matter is prevented from staying in the bearing hole, it is possible to prevent foreign matter from getting caught between the portion where the rotor is supported in the bearing hole and the rotating shaft.

  According to invention of Claim 2, the brushless motor is used as a drive source of the pump part of a fuel pump. The brushless motor has a sliding resistance between the commutator and the brush like the brush motor, an electric resistance between the commutator and the brush, and a fluid resistance received by a groove provided to divide the commutator into each segment. There is no loss problem. As a result, since the motor efficiency of the brushless motor is higher than that of the brush motor, the efficiency of the fuel pump is improved. Here, the efficiency of the fuel pump is the ratio of the amount of work performed by the fuel pump to the power supplied to the fuel pump, ie, the value of (fuel discharge pressure) × (fuel discharge amount). When the efficiency of the fuel pump is increased, the motor unit is smaller when the brushless motor is used than when the brush motor is used, so that the fuel pump can be downsized. Thus, the fuel pump miniaturized using the brushless motor is particularly suitable for use in a motorcycle.

In the invention according to claim 3, since the cover formed of resin directly supports the rotating shaft of the rotor, it is not necessary to provide a bearing separately from the cover. Therefore, the number of parts is reduced and the number of assembling steps of the fuel pump is reduced.
In the invention according to claim 5, since the cover is integrally formed of resin, the number of parts of the fuel pump is reduced and the number of assembling steps of the fuel pump is reduced.

  By the way, the bearing hole and the discharge port of the discharge passage that is open on the cover surface are formed on the same axis, that is, when the discharge port is formed in the center of the cover, the parts at a place other than the discharge port, For example, when a terminal or the like is installed on the surface of the cover or taken out from the inside of the cover, the distance between the terminal and the discharge port can be set only to be equal to or less than the radius of the cover even if they are separated. Therefore, particularly in a small fuel pump, the distance between the discharge port and other parts is reduced. As a result, for example, a space for connection between the terminal and the connector or between the discharge port and the piping becomes narrow, so that the connection work between the fuel pump and other parts becomes complicated.

Accordingly, in the invention described in claim 6, since the discharge port of the discharge passage is eccentric with respect to the bearing hole and the discharge port is formed away from the center portion of the cover, parts such as terminals are covered at locations other than the discharge port. The distance between the position to be installed on the surface or the position to be taken out from the inside of the cover and the discharge port can be as far as possible. Therefore, for example, the connection work between the terminal and the connector or the connection work between the discharge port and the piping becomes easy. Particularly, in the small fuel pump, the configuration of the invention described in claim 5 is effective.
In the invention according to claim 7, the bearing hole and the discharge passage are directly overlapped to communicate with each other. That is, since the bearing hole and the discharge passage also serve as the communication passage, the bearing hole and the discharge passage can be easily communicated with each other.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A fuel pump according to a first embodiment of the present invention is shown in FIGS. The fuel pump 10 of the present embodiment is an in-tank type turbine pump installed in a fuel tank of a two-wheeled vehicle having a displacement of 150 cc or less, for example.

  As shown in FIG. 1, the fuel pump 10 includes a pump unit 12 and a motor unit 13 that rotationally drives the pump unit 12. The housing 14 also serves as both the pump unit 12 and the motor unit 13. The housing 14 caulks the pump case 20 and the end cover 50 at both ends in the axial direction. The end cover 50 corresponds to the cover described in the claims. Further, the portion of the motor unit 13 where the housing 14 covers the outer periphery of the stator core 30 is thinner than the portion of the pump unit 12 where a step portion 15 described later is formed. As described above, the outer diameter of the motor unit 13 is reduced as much as possible by reducing the thickness of the housing 14 that covers the outer periphery of the stator core 30 that is unnecessary on the magnetic circuit.

  The pump unit 12 is a turbine pump having pump cases 20 and 22 and an impeller 24. The pump case 22 is abutted against the step portion 15 of the housing 14 in the axial direction. Thereby, positioning of the axial direction of the pump case 22 is made. A bearing 26 is installed in the center of the pump case 22 by press-fitting. The pump case 20 is caulked and fixed on one end side of the housing 14, and the axial pressure generated by the caulking causes the pump case 22 and the step portion 15, and the surface pressure against which the pump case 20 and the pump case 22 are pressed against each other in the axial direction. To ensure and seal the fuel.

  The pump cases 20 and 22 are pump cases that rotatably accommodate an impeller 24 as a rotating member. C-shaped pump passages 202 are respectively formed between the pump cases 20 and 22 and the impeller 24. The fuel sucked from the suction port 200 provided in the pump case 20 is pressurized in the pump passage 202 by the rotation of the impeller 24 and is pumped to the motor unit 13 side. The fuel pumped to the motor unit 13 side is supplied to the engine side from the discharge port 208 through the fuel passage 204 and the discharge passage 206 between the stator core 30 and the rotor 70. A discharge port 208 of a discharge passage 206 that opens to the outside from the end cover 50 is formed eccentrically with respect to a bearing 52 described later.

  The motor unit 13 is a so-called brushless motor, and includes a stator core 30, a bobbin 40, a coil 42, and a rotor 70. The stator core 30 is configured by arranging six cores 32 in the circumferential direction. A control device (not shown) controls the energization of the coil 42 according to the rotational position of the rotor 70, whereby the magnetic poles formed on the inner peripheral surface of each core 32 facing the rotor 70 are switched.

  As shown in FIG. 2, each core 32 has a tooth 33 and an outer peripheral portion 34, and is integrally formed by caulking and fixing magnetic steel plates laminated in the axial direction of a shaft 72 that is a rotating shaft. The teeth 33 protrude from the central portion of the outer peripheral portion 34 toward the inner rotor 70. Each core 32 is fitted with a bobbin 40 formed of an insulating resin. The outer peripheral portion 34 is formed in an arc shape having the same width in the circumferential direction, and the six outer peripheral portions 34 form an annular core.

  The coil 42 is formed by concentrically winding a winding for each core 32 around the outer periphery of the bobbin 40 in a single state before the six cores 32 are installed in the circumferential direction to form the stator core 30. Each coil 42 is electrically connected to the terminals 44 and 45 on the end cover 50 side shown in FIG. The terminal 44 is taken out of the end cover 50 from a portion electrically connected to the coil 42, exposed, and connected to the connector. The terminal 45 is not exposed from the end cover 50 and is used to electrically connect the coils 42 to each other.

  The terminals 44, 45 are spaced from the housing 14 at a position approximately equidistant from the bearing hole 52 formed in the center of the end cover 50 in order to ensure insulation from the radially outer metal housing 14. The end cover 50 is insert-molded. Further, the terminal 44 is bent at a position where the terminal 44 is taken out from the inside to the outside of the end cover 50 so as to be exposed from a radially outer side than a position inside the end cover 50. In this way, the terminal 44 is bent so as to be exposed from the radially outer side than the position inside the end cover 50, and the discharge port 208 is eccentric with respect to the bearing hole 52 as described above, and the center of the end cover 50 is Therefore, the terminal 44 exposed from the surface of the end cover 50 and the discharge port 208 can be separated as much as possible. Therefore, the connection between the terminal 44 and the connector, and the connection between the discharge port 208 and the piping are facilitated.

  The insulating resin material 46 is filled between the teeth 33 adjacent to each other in the circumferential direction, is resin-molded so as to cover the coil 42, and is an end that covers the end of the stator core 30 opposite to the pump portion 12. The cover 50 is integrally formed. As the material of the insulating resin material 46, PPS (polyphenylene sulfide) or POM (polyacetal) is suitable. In the end cover 50, the bearing hole 52 that receives the shaft 72, the support portion of the terminal 44, and the discharge port 208 are integrally formed of an insulating resin material 46. Since the insulating resin material 46 integrally forms the end cover 50, the number of parts constituting the fuel pump 10 is reduced, and the number of assembling steps of the fuel pump 10 is reduced.

  A bearing hole 52 for bearing the shaft 72 is formed in the end cover 50 at the center. The bearing hole 52 directly receives the shaft 72 and is closed at the bottom. The end cover 50 is formed with a discharge passage 206 that is eccentric from the bearing hole 52. The discharge passage 206 is formed in a straight line so as to penetrate the end cover 50 in the axial direction, and directly overlaps and communicates with the bearing hole 52.

  The fall prevention member 60 is formed in an annular shape having a through hole in the center, and is locked to the end portion of the bobbin 40 on the opposite side to the pump portion 12. The fall prevention member 60 has a fitting hole into which the terminals 44 and 45 are fitted. Since the insulating resin material 46 is resin-molded with the terminals 44 and 45 fitted in the fitting holes, it is possible to prevent the terminals 44 and 45 from falling down and interfering with surrounding parts when resin-molding.

  As shown in FIGS. 1 and 2, the rotor 70 has a shaft 72 and a permanent magnet 74 and is rotatably installed on the inner periphery of the stator core 30. One end of the shaft 72 is rotatably supported by the bearing 26 and the other end is rotatably supported by the bearing hole 52. The permanent magnet 74 is a plastic magnet formed into a cylindrical shape by kneading magnetic powder into a thermoplastic resin material such as PPS, and is directly formed on the outer periphery of the shaft 72 subjected to knurling by injection molding or the like. . The permanent magnet 74 forms eight magnetic pole portions 75 in the rotation direction. The eight magnetic pole portions 75 are magnetized so as to form different magnetic poles alternately in the rotational direction on the outer peripheral surface facing the stator core 30.

In the discharge port 208 formed by the end cover 50, a valve member 80, a stopper 82, and a spring 84 constituting a check valve are accommodated. Since the end cover 50 also serves as a check valve housing in this way, the number of parts constituting the fuel pump 10 is reduced, and the number of assembling steps of the fuel pump 10 is reduced.
When the fuel pressurized by the pump unit 12 reaches a predetermined pressure or higher, the valve member 80 lifts against the load of the spring 84 and the fuel is discharged from the discharge port 208 to the engine side. Further, the valve member 80 prevents the backflow of the discharged fuel discharged from the fuel pump 10.

  In the first embodiment, since the bearing hole 52 and the discharge passage 206 communicate with each other and new fuel flows through the bearing hole 52, new fuel flows through the sliding portion between the shaft 72 and the bearing hole 52. As a result, the fuel stays between the shaft 72 and the bearing hole 52 and deteriorates, and the shaft 72 is prevented from corroding by the deteriorated fuel, so that the smooth sliding between the bearing hole 52 and the shaft 72 can be maintained. . Further, even if foreign matter such as wear powder flows into the bearing hole 52, it quickly flows out into the discharge passage 206, so that foreign matter can be prevented from being caught between the bearing hole 52 and the shaft 72. Therefore, smooth sliding between the bearing hole 52 and the shaft 72 can be maintained.

  In the first embodiment, the discharge port 208 is eccentric with respect to the bearing hole 52, and the discharge passage 206 having the discharge port 208 and the bearing hole 52 are directly overlapped to communicate with each other, thereby forming the discharge passage 206 in a straight line. Therefore, after the end cover 50 is resin-molded, the molds can be pulled out in opposite directions. Therefore, the end cover 50 can be integrally formed of resin.

  In the first embodiment, the coil 42 is formed by concentrating the windings around the teeth 33 of each core 32, so that the space factor of the windings is increased as compared with, for example, distributed winding of the windings. To do. Therefore, if the winding amount is the same, the winding space occupied by the coil 42 is reduced. As a result, the motor unit 13 can be downsized and the fuel pump 10 can be downsized.

  Further, since the insulating resin material 46 is filled between the teeth 33 adjacent to each other in the circumferential direction and is resin-molded so as to cover the coil 42, the coil 42 is corroded by contact with the fuel with a simple configuration. This can prevent the coil 42 from coming into contact with the foreign matter. In addition, the insulating resin material 46 can prevent winding collapse of the coil 42 that is concentratedly wound.

(Second, third and fourth embodiments)
FIG. 4 shows a second embodiment of the present invention, FIG. 5 shows a third embodiment, and FIG. 6 shows a fourth embodiment. In addition, the same code | symbol is attached | subjected to substantially the same component as embodiment mentioned above.
In the second embodiment shown in FIG. 4, the bearing hole 102 formed in the end cover 100 and the discharge passage 206 do not directly overlap but are separated in the radial direction. The bottom of the bearing hole 102 is closed, and the bearing hole 102 and the discharge passage 206 communicate with each other through the communication passage 220.

  In the third embodiment shown in FIG. 5, the bearing hole 112 formed in the end cover 110 and the discharge port 208 of the discharge passage 206 are substantially on the same shaft 120, but the bearing hole 112 and the discharge passage 206 directly overlap each other. They are not in the radial direction. The bottom of the bearing hole 112 is closed, and the bearing hole 112 and the discharge passage 206 communicate with each other through the communication passage 220.

  In the fuel pump 130 of the fourth embodiment shown in FIG. 6, a metal bearing 140, which is a separate component from the resin end cover 132, is press-fitted into the bearing hole 134 formed in the end cover 132. The end cover 132 is integrally formed of the insulating resin material 46. The shaft 72 is rotatably supported by the bearing 26 and the bearing 140. As the material of the bearing 140, copper-based sintering or carbon is suitable in view of oil resistance.

  The bearing hole 134 is formed in the center part of the end cover 132, and the bottom part is closed. The discharge passage 206 formed eccentrically from the bearing hole 134 is in direct communication with the bearing hole 134 and communicates therewith. As a result, new fuel flows through the bearing hole 134, so that new fuel flows through the sliding portion between the shaft 72 and the bearing 140. Accordingly, the fuel stays between the shaft 72 and the bearing 140 and deteriorates, and the shaft 72 is prevented from being corroded by the deteriorated fuel, so that smooth sliding between the shaft 72 and the bearing 140 can be maintained. Even if foreign matter such as wear powder flows into the bearing hole 134, it quickly flows out into the discharge passage 206, so that foreign matter can be prevented from being caught between the shaft 72 and the bearing 140. Therefore, smooth sliding between the shaft 72 and the bearing 140 can be maintained.

(Other embodiments)
In the above embodiments, the brushless motor is used for the pump portion of the fuel pump, but a brush motor may be used. Even when a brush motor is used, the bearing hole with the closed bottom provided in the end cover is connected to the discharge passage to prevent fuel and foreign matter from staying in the bearing hole. Smooth sliding with can be maintained.

  In addition to integrally molding the end cover with resin, the end cover may be integrally formed by welding a plurality of resin members, or an extra opening portion of the integrally formed end cover may be sealed with a sealing plug or the like. It may be sealed. Further, the end cover may be integrally formed of a material such as metal other than resin.

In the above embodiments, the teeth that constitute the stator core and are installed in the circumferential direction are separated from each other. However, the teeth that are installed in the circumferential direction may be integrally formed.
Moreover, in the said some embodiment, although the pump part 12 was comprised with the turbine pump using the impeller 24, you may comprise a pump part with another pump structure, for example, a gear pump.
As described above, the present invention is not limited to the above-described plurality of embodiments, and can be applied to various embodiments without departing from the gist thereof.

Sectional drawing which shows the fuel pump by 1st Embodiment. II-II sectional view taken on the line of FIG. III-III sectional view taken on the line of FIG. The typical sectional view showing the end cover of the fuel pump by a 2nd embodiment. The typical sectional view showing the end cover of the fuel pump by a 3rd embodiment. Sectional drawing which shows the fuel pump by 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 130: Fuel pump, 12: Pump part, 13: Motor part (brushless motor), 14: Housing, 30: Stator core, 33: Teeth, 42: Coil, 46: Insulating resin material, 50, 100, 110, 132 : End cover (cover), 52, 102, 112: Bearing hole (bearing), 70: Rotor, 72: Shaft (rotating shaft), 74: Permanent magnet, 134: Bearing hole, 140: Bearing (metal bearing) 206: Discharge passage 208: Discharge port 220: Communication passage

Claims (7)

A stator,
A rotor rotatably installed on the inner peripheral side of the stator;
A coil that is installed on one of the stator or the rotor and generates a magnetic force that rotates the rotor between the stator and the rotor by energization;
A pump unit that is installed on one axial end side of the rotating shaft of the rotor and is driven to rotate by the rotor to suck in and boost fuel; and
A cover that covers the other axial end of the rotating shaft of the stator and the rotor, and that forms a discharge passage for discharging fuel pressurized by the pump unit; A bearing hole for bearing the other axial end of the shaft;
With
A fuel pump in which a bottom portion of the bearing hole is closed, and a communication passage that connects the discharge passage and the bearing hole is formed in the cover. The stator has a plurality of teeth installed in the circumferential direction,
The coil is formed by concentrating windings on the teeth, and switching the magnetic poles formed in the circumferential direction on the inner peripheral surface of the teeth by controlling energization,
The rotor is formed on the outer peripheral surface facing the teeth with different magnetic poles alternately in the rotation direction,
The fuel pump according to claim 1.   The fuel pump according to claim 1, wherein the cover is made of resin and directly supports the rotating shaft.   3. The fuel pump according to claim 1, wherein the cover is made of resin, and is provided with a metal bearing that is separate from the cover and is press-fitted into the bearing hole to bear the rotating shaft.   The fuel pump according to any one of claims 1 to 4, wherein the cover is integrally formed of resin.   The fuel pump according to any one of claims 1 to 5, wherein a discharge port of the discharge passage is eccentric with respect to the bearing hole. The fuel pump according to claim 6, wherein the bearing hole and the discharge passage are in direct communication with each other.

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