JP2017014931A - Fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel pump capable of reducing abrasion of an impeller caused by collision with a rotating shaft.SOLUTION: A fuel pump 1 includes a cylindrical stator 20 having a plurality of coils 23, a rotor 24 rotatably provided in a radial inner side of the stator 20, a shaft 25 coaxially provided with the rotor 24 and integrally rotatable with the rotor 24, an impeller 35 pressurizing fuel sucked from an inlet 151 when the shaft 25 is rotated and delivering the fuel from an outlet 171, and a fitting member 40 integrally rotating with the impeller 35. The fitting member 40 has a fitting hole 400 to which an end 252 of the shaft 25 is fitted, and is formed of a material having abrasion resistance higher than a material forming the impeller 35.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel pump.

  There is known a fuel pump that includes a pump unit having an impeller and a motor unit that has a shaft connected to the impeller and that generates a rotational torque capable of rotating the impeller, and pumps fuel in the fuel tank to the engine by the rotation of the impeller. Yes. In the fuel pump, the shaft is fitted into a fitting hole of the impeller, and the shaft and the impeller rotate together. For example, Patent Document 1 prevents wear of an impeller that is provided between an outer wall of a shaft that is fitted in a fitting hole and an inner wall of an impeller that forms the fitting hole and collides with the shaft when the shaft rotates. A fuel pump with a biasing member is described.

Japanese Utility Model Publication No. 06-37587

  However, in the fuel pump described in Patent Document 1, since the gap between the outer wall of the shaft fitted in the fitting hole and the inner wall of the impeller forming the fitting hole is relatively narrow, the biasing member is the shaft. It is difficult to generate an urging force enough to prevent the impeller from colliding with the impeller. For this reason, the rotating shaft may collide with the impeller and the impeller may be worn.

  It is an object of the present invention to provide a fuel pump that reduces impeller wear due to a collision with a rotating shaft.

  The present invention is a fuel pump, a pump case having a suction port and a discharge port, a stator, a rotor provided rotatably in the radial direction of the stator, a shaft provided coaxially with the rotor and rotatable integrally with the rotor, Wear resistance compared to the impeller that presses the fuel sucked from the suction port and discharges it from the discharge port, and the material that forms the impeller so as to rotate integrally with the impeller when the shaft rotates and is provided rotatably in the pump case And a fitting member having a fitting hole formed from a high material and fitted with one end of the shaft.

  In the fuel pump of the present invention, the impeller is provided with a fitting member having a fitting hole into which one end of the shaft is fitted. The fitting member is provided to rotate integrally with the impeller, and is formed of a material having higher wear resistance than the material forming the impeller. Thereby, when the shaft rotates, the shaft and the impeller do not directly collide with each other, so that the wear of the impeller due to the collision with the rotating shaft can be reduced.

It is sectional drawing of the fuel pump by 1st embodiment of this invention. It is a schematic diagram of the impeller and fitting member with which the fuel pump by 1st embodiment of this invention is provided. It is a fragmentary sectional view of the fuel pump by a first embodiment of the present invention. It is a schematic diagram of the impeller and fitting member with which the fuel pump by 2nd embodiment of this invention is provided. It is a fragmentary sectional view of the fuel pump by a second embodiment of the present invention. It is a schematic diagram of the impeller and fitting member with which the fuel pump by 3rd embodiment of this invention is provided. It is a fragmentary sectional view of the fuel pump by a fourth embodiment of the present invention. It is sectional drawing of the fuel pump by 5th embodiment of this invention. It is a schematic diagram of the impeller and fitting member with which the fuel pump by 5th embodiment of this invention is provided. It is a schematic diagram explaining the effect | action of the fuel pump by 5th embodiment of this invention.

  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 will be described with reference to FIGS.

  The fuel pump 1 includes a housing 10, a motor unit 6, a pump unit 7, a pump cover 15, a cover end 17, and the like. In the fuel pump 1, the motor unit 6 and the pump unit 7 are accommodated in a space formed by the housing 10, the pump cover 15, and the cover end 17. The fuel pump 1 sucks fuel in a fuel tank (not shown) from the suction port 151 and discharges the fuel from the discharge port 171 to the engine. 1 and 5, the upper side is the “top side” and the lower side is the “ground side”. The housing 10, the pump cover 15, and the cover end 17 correspond to a “pump case” described in the claims.

  The housing 10 is formed in a cylindrical shape from a metal such as iron. A pump cover 15 made of metal and a cover end 17 made of resin are provided at each of the two end portions 101 and 102 of the housing 10.

The pump cover 15 is provided so as to close the end 101 on the ground side of the housing 10. The pump cover 15 is fixed inside the housing 10 when the edge of the end 101 is crimped inward. The pump cover 15 has a suction port 151 that opens to the ground side. The suction port 151 communicates with a suction passage 152 that penetrates the pump cover 15 in the vertical direction. A groove 153 communicating with the suction passage 152 is formed on the top side of the pump cover 15.
In addition, the pump cover 15 has a recess 155 in which a ground-side end 252 serving as “one end” of the shaft 25 is positioned at the approximate center on the top side.

  The cover end 17 is molded from resin and is provided so as to close the top end 102 of the housing 10. The cover end 17 is fixed inside the housing 10 when the edge of the end portion 102 is crimped. The cover end 17 has a discharge port 171 that opens to the top side. The discharge port 171 communicates with a discharge passage 172 that penetrates the cover end 17 in the vertical direction. In addition, the cover end 17 is provided with an electrical connector portion 173 that accommodates a connection terminal 201 that receives power supplied from the outside in a portion different from the portion where the discharge passage 172 is formed. On the ground side of the cover end 17, a bearing housing portion 174 formed in a substantially cylindrical shape is provided. A bearing 26 is fitted in the bearing housing portion 174. The bearing 26 rotatably supports the top end 251 of the shaft 25.

  The motor unit 6 generates rotational torque using a magnetic field generated when electric power is supplied. The motor unit 6 includes a stator 20, a rotor 24, a shaft 25, and the like. The motor unit 6 of the fuel pump 1 according to the first embodiment is a brushless motor that can detect the position of the rotor 24 with respect to the stator 20 by the rotation of the shaft 25.

  The stator 20 is formed in a cylindrical shape and is accommodated on the radially outer side of the housing 10. The stator 20 includes six cores 21, six bobbins 22, six windings 23, three connection terminals 201, and the like. The stator 20 is integrally formed by molding these with resin.

  The core 21 is formed by overlapping a plurality of magnetic materials such as plate-like iron. The cores 21 are arranged in the circumferential direction and are provided at positions facing the magnets 243 of the rotor 24.

  The bobbin 22 is formed of a resin material, and is provided integrally with the core 21 by inserting the core 21 during molding.

  The winding 23 is, for example, a copper wire whose surface is covered with an insulating film. One winding 23 forms one coil by being wound around a bobbin 22 into which the core 21 is inserted. Winding 23 is electrically connected to connection terminal 201 housed in electrical connector portion 173.

  The connection terminal 201 passes through the cover end 17 and is fixed to the top side of the bobbin 22. In the fuel pump 1 according to the first embodiment, three connection terminals 201 are provided and receive three-phase power from a control unit (not shown).

  The rotor 24 is rotatably provided inside the stator 20. The rotor is provided with a magnet 243 around the iron core 242. The magnet 243 has N poles and S poles arranged alternately in the circumferential direction.

The shaft 25 is formed so that a cross section perpendicular to the central axis of a portion excluding the end portion 252 on the ground side has a substantially circular shape. The shaft 25 is press-fitted and fixed in a shaft hole 241 formed on the central axis of the rotor 24. Thereby, the shaft 25 rotates integrally with the rotor 24.
The end portion 252 on the ground side of the shaft 25 is formed so that a cross section perpendicular to the central axis is substantially rectangular. The ground-side end 252 is connected to the pump unit 7. The end 252 on the ground side has shaft contact surfaces 253 and 254 that extend in the vertical direction and are formed in a flat shape.

  The pump unit 7 pressurizes the fuel sucked from the suction port 151 using the rotational torque generated by the motor unit 6 and discharges the fuel into the housing 10. The pump unit 7 includes a pump casing 31, an impeller 35, and the like.

  The pump casing 31 is formed in a substantially disc shape from a metal, and is provided between the pump cover 15 and the stator 20. A through hole 311 that penetrates the pump casing 31 in the plate thickness direction is formed at the center of the pump casing 31. A bearing 27 is provided in the through hole 311. The bearing 27 supports the end 252 on the ground side of the shaft 25 so as to be rotatable. Thereby, the rotor 24 and the shaft 25 can rotate with respect to the cover end 17 and the pump casing 31.

  A groove 312 is formed on the ground side of the pump casing 31 at a position facing the groove 153 of the pump cover 15. The groove 312 communicates with a fuel passage 313 that penetrates the pump casing 31 in the vertical direction.

  The impeller 35 is formed in a substantially disk shape from polyphenylene sulfide resin. The impeller 35 is accommodated in a pump chamber 300 formed between the pump cover 15 and the pump casing 31. The impeller 35 has an accommodation hole 350 capable of accommodating the fitting member 40 at the center.

  The impeller 35 has a plurality of blade grooves 351 on the radially outer side of the accommodation hole 350. The blade groove 351 is provided at a position corresponding to the groove 153 and the groove 312. As shown in FIG. 2, the blade grooves 351 are provided at equal intervals in the circumferential direction at the radially outer end of the impeller 35.

  The fitting member 40 is a cylindrical member made of metal. The fitting member 40 is formed so as to be integrated with the impeller 35 by molding, for example. The fitting member 40 is accommodated in the accommodation hole 350 of the impeller 35. The fitting member 40 has a fitting hole 400 at the center of which the end 252 on the ground side of the shaft 25 can be fitted. The fitting member 40 rotates integrally with the shaft 25 when the end 252 on the ground side and the fitting hole 400 are fitted. That is, the fitting member 40 connects the shaft 25 and the impeller 35 so that the shaft 25 and the impeller 35 can rotate integrally.

  When the fitting member 40 is housed in the pump chamber 300 together with the impeller 35, the pump member 31 is fitted between the end surface 401 of the fitting member 40 on the pump casing 31 side and the end surface 314 of the pump casing 31 on the impeller 35 side. A gap is formed between the end surface 402 on the cover 15 side and the end surface 154 on the impeller 35 side of the pump cover 15. That is, the fitting member 40 is formed such that the thickness D40 in the direction of the central axis CA40 is thinner than the thickness D35 of the impeller 35 in the direction of the central axis CA40, as shown in FIG.

  Next, the operation of the fuel pump 1 will be described with reference to FIG.

  In the fuel pump 1, when electric power is supplied to the windings 23 of the motor unit 6 through the connection terminals 201, the impeller 35 rotates together with the rotor 24 and the shaft 25. When the impeller 35 rotates, the fuel in the fuel tank that houses the fuel pump 1 is sucked into the pump chamber 300 from the suction port 151. The sucked fuel flows as a spiral swirl between the blade groove 351 and the grooves 153 and 312 by the rotation of the impeller 35 and is pressurized. The pressurized fuel passes through the fuel passage 313 and is guided to the intermediate chamber 100 formed between the pump casing 31 and the motor unit 6.

  The fuel guided to the intermediate chamber 100 passes through a fuel passage 103 formed between the inner wall of the housing 10 and the outer wall of the stator 20, a fuel passage 104 formed between the rotor 24 and the stator 20, and the like. It is guided to the fuel passage 105 formed on the outer side in the radial direction of the housing portion 174. The fuel guided to the fuel passage 105 is discharged to the outside through the discharge passage 172 and the discharge port 171.

  The fuel pump 1 includes a fitting member 40 that rotates integrally with the impeller 35. The fitting member 40 has a fitting hole 400 into which the shaft 25 is fitted. Thereby, the rotational torque of the shaft 25 is transmitted to the impeller 35 through the fitting member 40. When the shaft 25 rotates, the ground-side end 252 of the shaft 25 collides with the inner wall of the fitting member 40 that forms the fitting hole 400, but the fitting member 40 is made of polyphenylene sulfide resin that forms the impeller 35. Compared to the impeller 35, it is less likely to be worn because it is made of a metal having higher wear resistance. Thereby, since the rotational torque of the shaft 25 is transmitted to the impeller 35 without the shaft 25 and the impeller 35 directly colliding with each other, the wear of the impeller 35 due to the rotation of the shaft 25 can be reduced.

  The fitting member 40 is formed such that the thickness D40 in the direction of the central axis CA40 is thinner than the thickness D35 of the impeller 35 in the direction of the central axis CA40. Thereby, even if the fitting member 40 rotates with the impeller 35 in the pump chamber 300, it is possible to prevent the fitting of the pump casing 31 and the pump cover 15 made of metal and the fitting member 40. Therefore, it is possible to prevent the fitting member 40 from being seized on the pump casing 31 or the pump cover 15 due to the friction between the metals, and to prevent a problem from occurring in the rotation of the impeller 35.

  If the thickness D40 of the fitting member 40 is made thinner than the thickness D35 of the impeller 35, the gap between the fitting member 40 and the pump casing 31 and the pump cover 15 becomes relatively large. As a result, foreign matter is less likely to be caught between the metal fitting member 40 and the pump casing 31 and the pump cover 15 made of metal, so that the rotation of the impeller 35 is prevented from being locked by the foreign matter being caught. can do.

(Second embodiment)
Next, a fuel pump according to a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment in the shape of the fitting member. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st embodiment, and description is abbreviate | omitted.

  FIG. 4 shows a schematic diagram of the impeller 45 and the fitting member 50 provided in the fuel pump 2 according to the second embodiment.

  The impeller 45 is formed in a substantially disc shape from polyphenylene sulfide resin. The impeller 45 is accommodated in a pump chamber 300 formed between the pump cover 15 and the pump casing 31. The impeller 45 has an accommodation hole 450 capable of accommodating the fitting member 50 at the center. The impeller 45 has a plurality of blade grooves 451 provided on the radially outer side of the accommodation hole 450 so as to correspond to the grooves 153 and 312.

The fitting member 50 is a substantially cylindrical member made of metal. The fitting member 50 is accommodated in the accommodation hole 450 of the impeller 45 and can be rotated integrally with the shaft 25. The fitting member 50 is formed of a main body 51 and a plurality of protrusions 52.
The main body 51 is a part formed in a cylindrical shape. The main body 51 has a fitting hole 500 at the center where the end 252 on the ground side of the shaft 25 can be fitted.

  The protrusion 52 is provided on the outer wall on the radially outer side of the main body 51 so as to protrude in the radially outward direction. The protrusions 52 are provided at equal intervals in the circumferential direction. In the second embodiment, four protrusions 52 are provided. The protrusion 52 is inserted into an insertion hole 452 provided in the impeller 45. As shown in FIG. 5, the insertion hole 452 is formed substantially at the center of the inner wall that forms the accommodation hole 450. Thereby, the protrusion 52 can be engaged with the impeller 45.

  In the fuel pump 2, the protrusion 52 is engaged with the inner wall of the impeller 45 that forms the insertion hole 452. Thereby, for example, even if a gap is formed between the impeller 45 and the fitting member 50 due to a difference in coefficient of linear expansion between the polyphenylene sulfide resin forming the impeller 45 and the metal forming the fitting member 50, the impeller 45 The relative movement of the fitting member 50 with respect to is restricted. Therefore, 2nd embodiment can prevent the rattling of the fitting member 50 with respect to the impeller 45 while having the effect of 1st embodiment.

(Third embodiment)
Next, a fuel pump according to a third embodiment of the present invention will be described with reference to FIG. The third embodiment differs from the first embodiment in the shape of the impeller. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st embodiment, and description is abbreviate | omitted.

  A schematic diagram of the impeller 55 and the fitting member 40 included in the fuel pump according to the third embodiment is shown in FIG.

  The impeller 55 is formed in a substantially disc shape from polyphenylene sulfide resin. The impeller 55 is accommodated in a pump chamber 300 formed between the pump cover 15 and the pump casing 31. The impeller 55 has an accommodation hole 550 that can accommodate the fitting member 40 at the center. Further, the impeller 55 has a plurality of blade grooves 551 provided on the radially outer side of the accommodation hole 550 so as to correspond to the grooves 153 and 312.

  The impeller 55 has a plurality of through holes 552 between the accommodation hole 550 and the blade groove 551. In the third embodiment, the impeller 55 has six through holes 552. The through holes 552 are formed so as to penetrate the impeller 55 in the vertical direction, and are formed at equal intervals in the circumferential direction with respect to the central axis CA55 of the impeller 55.

  In the fuel pump according to the third embodiment, when the shaft 25 rotates, the fitting member 40 may be deformed by an impact in a collision between the ground-side end portion 252 and the fitting member 40. When the fitting member 40 is deformed, the stress due to the deformation acts on the impeller 55 that houses the fitting member 40. In the fuel pump of the third embodiment, the stress in the impeller 55 is absorbed by a plurality of through holes 552 formed circumferentially at equal intervals with respect to the central axis CA55 of the impeller 55, and the impeller 55 is deformed by the stress. To prevent. Thereby, the third embodiment has the effects of the first embodiment and can prevent the impeller 55 from being damaged by the stress generated by the collision between the shaft 25 and the fitting member 40.

(Fourth embodiment)
Next, a fuel pump according to a fourth embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in the relationship between the pump casing, the cover end, and the fitting member. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st embodiment, and description is abbreviate | omitted.

  FIG. 7 shows a partial cross-sectional view of the fuel pump 4 according to the fourth embodiment. The fuel pump 4 includes an impeller 35, a fitting member 60, and the like.

  The fitting member 60 is a substantially cylindrical member made of metal. The fitting member 60 is accommodated in the accommodation hole 350 of the impeller 35. The fitting member 60 has a fitting hole 600 at the center of which the end 252 on the ground side of the shaft 25 can be fitted. The fitting member 60 rotates integrally with the shaft 25 when the end 252 on the ground side and the fitting hole 600 are fitted.

  In the fourth embodiment, the inner diameter of the accommodation hole 350 of the impeller 35 that accommodates the fitting member 60 is smaller than the inner diameter D311 of the through hole 311 of the pump casing 31 and the inner diameter D155 of the recess 155 of the pump cover 15. That is, the outer diameter D60 of the fitting member 60 is smaller than the inner diameter D311 of the through hole 311 and the inner diameter D155 of the recess 155.

  In the fourth embodiment, the fitting member 60 made of metal is provided at a position where the pump casing 31 and the pump cover 15 do not slide. Thereby, 4th embodiment has the same effect as 1st embodiment.

(Fifth embodiment)
Next, a fuel pump according to a fifth embodiment of the present invention will be described with reference to FIGS. The fifth embodiment is different from the first embodiment in that a control unit capable of detecting the magnitude of the current flowing through the winding is provided. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st embodiment, and description is abbreviate | omitted.

  A sectional view of the fuel pump 5 according to the fifth embodiment is shown in FIG. The fuel pump 5 includes a housing 10, a motor unit 6, a pump unit 7, a pump cover 15, a cover end 17, a control unit 68, and the like.

  As shown in FIG. 9, the shaft 65 of the motor unit 6 is formed so that a cross-sectional shape perpendicular to the central axis of the ground-side end portion 652 as “one end portion” is substantially D-shaped. . The end 652 on the ground side has a shaft contact surface 653 formed in a planar shape extending in the top-to-bottom direction, and a curved shaft outer wall 654 connecting both ends substantially parallel to the central axis of the shaft contact surface 653.

  The impeller 75 included in the pump unit 7 is formed in a substantially disk shape from polyphenylene sulfide resin. The impeller 75 is accommodated in the pump chamber 300. The impeller 75 has an accommodation hole 750 capable of accommodating the fitting member 70 at the center. The impeller 75 has a plurality of blade grooves 751 on the outer side in the radial direction of the accommodation hole 750. The blade groove 751 is provided at a position corresponding to the groove 153 and the groove 312.

  The fitting member 70 included in the pump unit 7 is a substantially cylindrical member made of metal. The fitting member 70 is accommodated in the accommodation hole 750 of the impeller 75. The fitting member 70 has a fitting hole 700 capable of fitting the end 652 on the ground side of the shaft 65 at the center. The fitting hole 700 is formed so that the shape perpendicular to the central axis is D-shaped. The fitting member 70 rotates integrally with the shaft 65 when the end 652 on the ground side and the fitting hole 700 are fitted.

  The control unit 68 is electrically connected to a connection terminal 201 provided on the cover end 17. The control unit 68 can control the magnitude of the current flowing through the winding 23. Further, the control unit 68 can detect the magnitude of the current flowing through the winding 23.

When a malfunction occurs in the rotation of the impeller 75 due to foreign matter entering between the pump casing 31 or the pump cover 15 and the impeller 75, the control unit 68 supplies power to the winding 23 so as to remove the foreign matter. Hereinafter, a method for removing foreign matter will be described with reference to FIG.
FIG. 10 shows a state where the end 652 on the ground side of the shaft 65 is fitted in the fitting hole 700. Since the size of the ground-side end portion 652 is smaller than the size of the fitting hole 700, as shown in FIG. 10, the fitting that forms the fitting hole 700 with the outer wall on the radially outer side of the ground-side end portion 652. A gap is formed between the inner wall of the member 70.

  In the fuel pump 5, when the fuel in the fuel tank is sucked and discharged, the shaft 65 rotates in one direction, specifically in the clockwise direction R1 in FIG. Thereby, one side 655 of the shaft contact surface 653 of the end 652 on the ground side that is connected to the shaft outer wall 654 contacts the inner wall of the fitting member 70 that forms the fitting hole 700, and the fitting member 70 and The rotational torque of the shaft 65 is transmitted to the impeller 75. The clockwise direction R1 shown in FIG. 10A corresponds to “the direction in which the shaft rotates when the fuel sucked from the suction port is pressurized” described in the claims.

  If foreign matter enters between the pump casing 31 or the pump cover 15 and the impeller 75, the foreign matter becomes resistance and the rotation of the impeller 75 becomes slow. In the fuel pump 5, the current flowing through the winding 23 can be increased by the control unit 68 to maintain a predetermined rotation speed. However, when the resistance of the foreign matter is large and the current flowing through the winding 23 exceeds a preset threshold value, the control unit 68 reverses the direction of current flow, and as shown in FIG. Is rotated in the counterclockwise direction R2. Thereby, the other side 656 connected to the shaft outer wall 654 of the shaft contact surface 653 of the end portion 652 on the ground side contacts the inner wall of the fitting member 70 forming the fitting hole 700, and the fitting member 70 and The rotational torque of the shaft 65 is transmitted to the impeller 75. At this time, since the shaft 65 in which one side 655 of the shaft contact surface 653 is in contact with the fitting member 70 rotates counterclockwise, the other side 656 of the shaft contact surface 653 is fitted vigorously. It contacts the member 70. The counterclockwise direction R2 shown in FIG. 10B corresponds to “a direction opposite to the direction in which the shaft rotates when the fuel sucked from the suction port is pressurized” described in the claims.

  When the fitting member 70 and the impeller 75 rotate counterclockwise, the foreign matter that has entered between the pump casing 31 or the pump cover 15 and the impeller 75 is removed. When the foreign matter is removed, the control unit 68 again causes a current to flow in the winding 23 so as to rotate the shaft 65 in the clockwise direction R3 shown in FIG. Thereby, the fitting member 70 and the impeller 75 rotate in the clockwise direction R3 so that the fuel in the fuel tank can be sucked and discharged. The clockwise direction R3 shown in FIG. 10C corresponds to “the direction in which the shaft rotates when the fuel sucked from the suction port is pressurized” described in the claims.

  In the fuel pump 5, when the magnitude of the current flowing through the winding 23 exceeds the threshold value, the control unit 68 flows a current in which plus and minus are reversed in the winding 23. Thereby, since the impeller 75 and the fitting member 70 rotate in the opposite direction to the case where the fuel in the fuel tank is sucked and discharged, the foreign matter entering between the pump casing 31 or the pump cover 15 and the impeller 75 is rotated. Can be eliminated. In the fifth embodiment, the shaft 65 collides with the fitting member 70 made of metal when the rotation of the shaft 65 is switched from clockwise to counterclockwise or from counterclockwise to clockwise. 75 is not damaged by switching the rotation direction of the shaft 65. Thereby, 5th embodiment has the same effect as 1st embodiment, and can prevent stop of fuel pump 5 by entrance of a foreign material.

(Other embodiments)
In the first to fourth embodiments, the ground-side end portion of the shaft that is fitted in the fitting hole of the impeller has two shaft contact surfaces. The shaft contact surface may be one as in the fifth embodiment. Moreover, in 5th embodiment, there may be two shaft contact surfaces like 1st-4th embodiment.

  In the above-described embodiment, the fitting member is made of metal. However, the material forming the fitting member is not limited to this. For example, any material may be used as long as it has higher wear resistance than the material forming the impeller such as PEK resin.

  In the above-described embodiment, the fitting member is accommodated in the accommodation hole of the impeller. However, the fitting member only needs to have a fitting hole that is provided so as to rotate integrally with the impeller and into which the end of the shaft on the ground side can be fitted.

  In the above-described embodiment, the fitting member is integrated with the impeller by being molded on the impeller. However, the method of integrating the fitting member and the impeller is not limited to this. The fitting member may be insert-molded, or the fitting member and the impeller may be welded.

  In the second embodiment, the fitting member has four protrusions. The number of protrusions is not limited to this.

  In the third embodiment, the impeller has a through hole that absorbs stress in the impeller. However, it is not necessary for the through holes to absorb the stress. Any space may be used as long as it is arranged in the circumferential direction and at equal intervals with respect to the central axis of the impeller. Also, the number need not be six.

  As mentioned above, this invention is not limited to such embodiment, It can implement with a various form in the range which does not deviate from the summary.

1, 2, 4, 5 ... Fuel pump 10 ... Housing (pump case)
15 ... Pump cover (pump case)
17 ... Cover end (pump case)
20 ... Stator 24 ... Rotor 25, 65 ... Shaft 35, 45, 55, 75 ... Impeller 40, 50, 60, 70 ... Fitting member 400, 500, 600, 700 ...・ Fitting hole

Claims (6)

A pump case (10, 15, 17) having a suction port (151) for sucking fuel and a discharge port (171) for discharging fuel;
A cylindrical stator (20) having a plurality of windings (23) and fixed to the pump case;
A rotor (24) rotatably provided on the radially inner side of the stator;
A shaft (25, 65) provided coaxially with the rotor and rotatable integrally with the rotor;
An impeller (35, 45, 55, 75) that is rotatably provided in the pump case, pressurizes the fuel sucked from the suction port when the shaft rotates, and discharges the fuel from the discharge port;
A fitting hole provided so as to rotate integrally with the impeller, formed of a material having higher wear resistance than that of the material forming the impeller, and fitted with one end (252, 652) of the shaft. A fitting member (40, 50, 60, 70) having (400, 500, 600, 700);
A fuel pump comprising: The fitting member has a protrusion (52) protruding radially outward,
The fuel pump according to claim 1, wherein the protrusion is engaged with the impeller.   The fitting member is characterized in that a thickness (D40) of the fitting member in the central axis (CA40) direction is thinner than a thickness (D35) of the impeller in the central axis direction of the fitting member. Or the fuel pump of 2.   The fuel pump according to any one of claims 1 to 3, wherein the impeller has a plurality of spaces arranged circumferentially at equal intervals with respect to a central axis (CA55) of the impeller.   The fuel pump according to any one of claims 1 to 4, wherein the fitting member is molded on the impeller. A control unit (68) capable of controlling the current flowing through the winding;
When the magnitude of the current flowing through the winding exceeds a threshold, the control unit is opposite to the normal rotation direction (R1, R3), which is the direction in which the shaft rotates when pressurizing the fuel sucked from the suction port. The fuel according to any one of claims 1 to 5, wherein the current flowing through the winding is controlled so as to rotate the shaft in the forward rotation direction after rotating the shaft in the direction (R2). pump.

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