JP2015083827A - Fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel pump which prevents the breakage of an impeller.SOLUTION: An impeller 65 which pressurizes fuel by rotation has a fit hole 66 fit with a shaft 52. The fit hole 66 is formed of a circular face 67, an impeller reverse direction abutting face 68 and an impeller forward direction abutting face 69. When a plane including an intersection line 666 between the impeller reverse direction abutting face 68 and the impeller forward direction abutting face 69, and contacting with the impeller reverse direction abutting face 68 in the vicinity of the intersection line 666 is set as a virtual plane 667, the impeller reverse direction abutting face 68 is formed so as to separate from the virtual plane 667 to a direction opposite to a center shaft CA65 side as a cross section progresses toward an intersection line 671 from the intersection line 666. When the shaft 52 rotates so that the other face 525 of a shaft abutting face 523 abuts on the impeller reverse direction abutting face 68, a region 520 at the inside of a radial direction of the shaft 52 abuts on the impeller 65. By this constitution, rotation torque acting on the impeller 65 can be reduced.

Description

  The present invention relates to a fuel pump.

  2. Description of the Related Art There is known a fuel pump that includes an impeller that can rotate in a pump chamber and a motor that generates a driving force for rotating the impeller, and that pumps fuel in a fuel tank to an internal combustion engine by the rotation of the impeller. Patent Document 1 describes a fuel pump including an impeller having a fitting hole in which a cross section is formed in a D shape and into which a motor shaft is fitted.

JP 2003-193990 A

  In a fuel pump that uses a brushless motor as a motor, when the impeller starts rotating, the shaft is rotated in the opposite direction to the forward direction, which is the direction in which the impeller rotates to pressurize the fuel, and the rotor with respect to the stator is rotated. The position of is detected. Since there is a manufacturing tolerance in the size of the fitting hole of the impeller, a gap is formed between the inner wall forming the fitting hole and the side wall of one end of the shaft. One end of the shaft rotates in the fitting hole when the shaft moves from a state where the shaft can rotate in the forward direction to a state where the shaft can rotate in the reverse direction, and the inner wall of the fitting hole when the shaft is accelerated to some extent Collide with. For this reason, there exists a possibility that the rotational torque of a shaft may act on an impeller and an impeller may be damaged.

  An object of the present invention is to provide a fuel pump that prevents the impeller from being damaged.

  The present invention includes a pump case, a stator, a rotor, a shaft provided coaxially with the rotor and rotating integrally with the rotor, a fitting hole into which one end of the shaft is fitted, and the shaft rotates. An impeller that pressurizes fuel sucked from the suction port and discharges the fuel from the discharge port, and the shaft is in a reverse direction that is opposite to a positive direction that is a direction in which the impeller rotates when pressurizing the fuel. When the shaft rotates, the portion on the radially inner side of the shaft abuts on the impeller.

  In the fuel pump, the impeller and the shaft are connected so as to rotate integrally through a fitting hole of the impeller. There is a certain tolerance in the size of the fitting hole, and if the shaft rotation direction is switched from the forward direction in which the impeller pressurizes fuel to the opposite direction, which is the opposite direction, the inside of the fitting hole The shaft rotates. When the shaft is rotated in the reverse direction so that the impeller is rotated in the reverse direction from the state where the shaft and the impeller are in contact with each other so as to rotate the impeller in the forward direction, the shaft is accelerated to some extent while the shaft is accelerated to the inner wall of the fitting hole. collide. In the fuel pump of the present invention, when the shaft rotates in the reverse direction, one end of the shaft and the inner wall of the fitting hole are formed so that the radially inner portion of the shaft and the impeller come into contact with each other. Thereby, since the rotational torque of the shaft acts on the impeller at a position relatively close to the rotational axis of the shaft, the rotational torque acting on the impeller becomes relatively small. Therefore, the impeller can be prevented from being damaged by the rotational torque of the shaft.

It is sectional drawing of the fuel pump by 1st Embodiment of this invention. It is a principal part enlarged view of the impeller of the fuel pump by 1st Embodiment of this invention. It is the III section enlarged view of FIG. It is a schematic diagram explaining the effect | action of the fuel pump by 1st Embodiment of this invention. It is a principal part enlarged view of the impeller of the fuel pump by 2nd Embodiment of this invention. It is a principal part enlarged view of the impeller of the fuel pump by 3rd Embodiment of this invention. It is a principal part enlarged view of the impeller of the fuel pump by 4th 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 motor unit 3, a pump unit 4, a housing 20, a pump cover 60, a cover end 40, and the like. In the fuel pump 1, the motor unit 3 and the pump unit 4 are accommodated in a space formed by the housing 20, the pump cover 60, and the cover end 40. The fuel pump 1 sucks fuel in a fuel tank (not shown) from a suction port 61 shown at the lower side of FIG. 1 and discharges it to an internal combustion engine from a discharge port 41 shown at the upper side of FIG. In FIG. 1, the upper side is “top side” and the lower side is “ground side”. The housing 20, the pump cover 60, and the cover end 40 correspond to a “pump case” described in the claims.

  The housing 20 is formed in a cylindrical shape from a metal such as iron. A pump cover 60 and a cover end 40 are provided at two ends 201 and 202 of the housing 20.

  The pump cover 60 closes the end 201 on the suction port 61 side of the housing 20. The pump cover 60 is fixed inside the housing 20 by crimping the edge of the end portion 201 of the housing 20 inward, so that the fuel pump 1 is prevented from coming off in the axial direction. The pump cover 60 has a suction port 61 that opens to the ground side. A suction passage 62 that penetrates the pump cover 60 in the direction of the rotation axis CA52 of the shaft 52 is formed inside the suction port 61. A groove 63 connected to the suction passage 62 is formed on the surface of the pump cover 60 on the pump unit 4 side.

  The cover end 40 is molded from resin and closes the end 202 on the discharge port 41 side of the housing 20. The cover end 40 is fixed inside the housing 20 by crimping the edge of the end portion 202 of the housing 20, so that the fuel pump 1 is prevented from coming off in the axial direction. The cover end 40 has a discharge port 41 that opens to the top side. A discharge passage 42 that penetrates the cover end 40 in the direction of the rotation axis CA 52 of the shaft 52 is formed inside the discharge port 41. An electrical connector portion 43 that houses a connection terminal 38 that receives power from the outside is provided at the end of the cover end 40 opposite to the side where the discharge passage 42 is formed.

  A bearing housing portion 44 formed in a substantially cylindrical shape is provided on the inner side of the housing 20 of the cover end 40. The bearing accommodating portion 44 has an accommodating space 440 for accommodating the end portion 521 of the shaft 52 and the bearing 55 that rotatably supports the end portion 521 therein.

  The motor unit 3 generates rotational torque using a magnetic field generated when electric power is supplied. The motor unit 3 includes a stator 10, a rotor 50, a shaft 52, and the like. The motor unit 3 of the fuel pump 1 according to the first embodiment is a brushless motor that detects the position of the rotor 50 with respect to the stator 10 by the rotation of the shaft 52.

  The stator 10 has a cylindrical shape and is accommodated on the radially outer side in the housing 20. The stator 10 has six cores 12, six bobbins, six windings, three connection terminals, and the like. The stator 10 is integrally formed by molding these with resin.

  The core 12 is formed by overlapping a plurality of magnetic materials such as plate-like iron. The cores 12 are arranged in the circumferential direction and are provided at positions facing the magnets 54 of the rotor 50.

  The bobbin 14 is formed from a resin material, and the core 12 is inserted and formed integrally with the core 12 at the time of formation. The bobbin 14 includes an upper end portion 141 formed on the discharge port 41 side, an insert portion 142 into which a core is inserted, and a lower end portion 143 formed on the suction port 61 side.

  The winding is, for example, a copper wire whose surface is covered with an insulating film. One winding forms one coil by being wound around the bobbin 14 in which the core 12 is inserted. One winding is formed on the upper end winding portion 161 wound around the upper end portion 141 of the bobbin 14, the insert winding portion (not shown) wound around the insert portion 142 of the bobbin 14, and the lower end portion 143 of the bobbin 14. It is comprised from the lower end winding part 163 etc. which are wound. The winding is electrically connected to the connection terminal 38 accommodated in the electrical connector portion 43.

  The connection terminal 38 passes through the cover end 40 and is fixed to the upper end portion 141 of the bobbin 14. In the fuel pump 1 according to the first embodiment, three connection terminals 38 are provided to receive three-phase power from a power supply device (not shown).

  The rotor 50 is rotatably accommodated inside the stator 10. The rotor is provided with a magnet 54 around the iron core 53. The magnet 54 has N and S poles arranged alternately in the circumferential direction. In the first embodiment, N poles and S poles are provided as 2 pole pairs, for a total of 4 poles.

  The shaft 52 is press-fitted and fixed in a shaft hole 51 formed on the central axis of the rotor 50, and rotates together with the rotor 50. An end 522 of the shaft 52 on the inlet 61 side is connected to the pump unit 4.

  The pump unit 4 pressurizes the fuel sucked from the suction port 61 using the rotational torque generated by the motor unit 3 and discharges the fuel into the housing 20. The pump unit 4 includes a pump casing 70, an impeller 65, and the like.

  The pump casing 70 is formed in a substantially disc shape and is provided between the pump cover 60 and the stator 10. A through hole 71 penetrating the pump casing 70 in the plate thickness direction is formed at the center of the pump casing 70. A bearing 56 is fitted in the through hole 71. The bearing 56 rotatably supports the end portion 522 of the shaft 52. Thereby, the rotor 50 and the shaft 52 can rotate with respect to the cover end 40 and the pump casing 70.

  Further, a groove 73 is formed on the surface of the pump casing 70 on the impeller 65 side, at a position facing the groove 63 of the pump cover 60. The groove 73 communicates with a fuel passage 74 that penetrates the pump casing 70 in the direction of the rotation axis CA52 of the shaft 52.

  The impeller 65 is formed in a substantially disk shape with resin. The impeller 65 is accommodated in a pump chamber 72 between the pump cover 60 and the pump casing 70.

  A fitting hole 66 into which the end 522 of the shaft 52 is fitted is formed in the approximate center of the impeller 65. The end portion 522 of the shaft 52 has a shaft contact surface 523 formed in a flat shape extending in the vertical direction, and the cross-sectional shape perpendicular to the rotation axis CA52 is substantially D-shaped as shown in FIG. It is formed as follows. The shaft contact surface 523 can contact the inner wall surface of the impeller 65 that forms the fitting hole 66. Thereby, the impeller 65 rotates in the pump chamber 72 by the rotation of the shaft 52. The detailed shape of the fitting hole 66 of the impeller 65 will be described later.

  Around the fitting hole 66 of the impeller 65, through holes 651, 652, 653 that penetrate the impeller 65 in the axial direction of the fuel pump 1 are formed. The through holes 651, 652, and 653 communicate the suction port 61 side and the discharge port 41 side of the impeller 65 of the pump chamber 72, and the fuel flows so that the fuel pressure in the pump chamber 72 is not biased.

  The impeller 65 has an inclined surface 64 formed at a position corresponding to the groove 63 and the groove 73. As shown in FIG. 2, the inclined surfaces 64 are provided at equal intervals in the circumferential direction at the radially outer end of the impeller 65.

  In the fuel pump 1 according to the first embodiment, the impeller 65 rotates together with the rotor 50 and the shaft 52 when electric power is supplied to the winding of the motor unit 3 via the connection terminal 38. When the impeller 65 rotates, the fuel in the fuel tank that houses the fuel pump 1 is guided to the groove 63 via the suction port 61. The fuel guided to the groove 63 is pressurized by the rotation of the impeller 65 and is guided to the groove 73. The pressurized fuel passes through the fuel passage 74 and is guided to the intermediate chamber 200 formed between the pump casing 70 and the motor unit 3.

  The fuel guided to the intermediate chamber 200 is in a fuel passage 204 between the rotor 50 and the stator 10, a fuel passage 205 between the outer wall of the shaft 52 and the inner wall 144 of the bobbin 14, and radially outward of the bearing housing portion 44. It passes through the formed fuel passage 206. The fuel guided to the intermediate chamber 200 passes through a fuel passage 203 formed between the inner wall of the housing 20 and the outer wall of the stator 10. The fuel passing through the fuel passages 203, 204, 205, 206 is discharged to the outside through the discharge passage 42 and the discharge port 41.

  The fuel pump 1 according to the first embodiment is characterized by the shape of the fitting hole 66 of the impeller 65. Here, based on FIGS. 2-4, the detailed shape of the impeller 65 is demonstrated. FIG. 2 is a top view of the impeller 65. FIG. 3 is an enlarged view of a portion III in FIG. 2, and is an enlarged view of a portion where the fitting hole 66 of the impeller 65 is formed. FIG. 4 is a schematic diagram showing the positional relationship between the fitting hole 66 and the shaft 52 when the fuel pump 1 is driven. A solid line arrow R1 shown in FIG. 4B indicates a reverse direction R1 that is a direction opposite to the normal direction in which the impeller 65 rotates when the impeller 65 pressurizes the fuel. Moreover, the solid line arrow R2 shown in FIG.4 (c) shows the positive direction R2 which is the direction which the impeller 65 rotates when the impeller 65 pressurizes a fuel. In FIG. 4, for convenience of explanation, the shape of the impeller reverse direction contact surface 68 is exaggerated from the actual shape.

  As shown in FIG. 3, the fitting hole 66 is connected to an arcuate surface 67 and an arcuate surface 67 whose cross-sectional shape is formed in an arcuate shape centering on the central axis CA65 of the impeller 65, and extends in the vertical direction from the arcuate surface 67. Impeller reverse direction contact surface 68 forming intersection line 671, and impeller reverse direction contact surface 68 connected to impeller reverse direction contact surface 68 while forming intersection line 672 connected to arc surface 67 and extending in the vertical direction with arc surface 67. An impeller positive direction contact surface 69 that forms an intersection line 666 with the contact surface 68 is formed. The fitting hole 66 is formed in a substantially D shape so that the cross-sectional shape thereof matches the cross-sectional shape of the end portion 522 of the shaft 52. The impeller reverse direction contact surface 68, the impeller positive direction contact surface 69, and the arc surface 67 are formed to extend in the vertical direction, that is, the direction of the central axis CA65 of the impeller 65.

  The impeller reverse direction contact surface 68 is formed from a single curved surface, and as illustrated in FIG. 3, the cross-sectional shape is formed to be a curve that curves in the direction of the through hole 652 when viewed from a point on the intersection line 666. ing. Specifically, if a virtual plane that includes the intersection line 666 and is in contact with the impeller reverse direction contact surface 68 in the vicinity of the intersection line 666 is a virtual plane 667, the impeller reverse direction contact surface 68 has a cross-sectional shape of the intersection line 666. From the imaginary plane 667 to the direction opposite to the central axis CA65 side as it goes toward the intersection line 671. At this time, the distance D1 between the intersection line 671 and the central axis CA65 is larger than the distance D0 between the circular arc surface 67 and the central axis CA65.

  The impeller positive direction contact surface 69 is formed in a flat shape. Specifically, as shown in FIG. 3, when a virtual plane that includes the intersection line 666 and is in contact with the impeller positive direction contact surface 69 in the vicinity of the intersection line 666 is a virtual plane 668, the impeller positive direction contact surface 69 is It is formed so as to be located on the virtual plane 668. At this time, the distance D2 between the intersection line 672 and the central axis CA65 is the same as the distance D0 between the circular arc surface 67 and the central axis CA65.

  In the fuel pump 1 according to the first embodiment, the shaft 52 rotates in the forward direction when the impeller 65 pressurizes the fuel. At this time, one surface 524 serving as a “shaft positive direction contact surface” constituting the shaft contact surface 523 of the shaft 52 rotates the impeller 65 while contacting the impeller positive direction contact surface 69. For this reason, when the driving of the fuel pump 1 is stopped by stopping the engine mounted on the vehicle, one surface 524 remains in contact with the impeller positive direction contact surface 69 as shown in FIG. It becomes.

  Next, when the fuel pump 1 is driven, the fuel pump 1 rotates the shaft 52 in the reverse direction R1 in order to detect the position of the rotor 50 with respect to the stator 10. At this time, the other surface 525 as the “shaft reverse direction contact surface” of the shaft contact surface 523 capable of contacting the impeller reverse direction contact surface 68 is, as shown in FIG. It is in a position away from the contact surface 68. For this reason, when the shaft 52 rotates in the reverse direction R1, the other surface 525 contacts the impeller reverse direction contact surface 68 while accelerating to some extent. In the fuel pump 1 according to the first embodiment, the impeller reverse direction contact surface 68 is formed so as to be separated from the virtual plane 667 as it goes radially outward from a point on the intersection line 666. That is, the radially outer side of the impeller reverse direction contact surface 68 is a flank so as not to contact the shaft contact surface 523. As a result, the surface of the other surface 525 on the radially inner side of the shaft 52 (the portion surrounded by the two-dot chain line circle in FIGS. 3 and 4B) 520 and the impeller reverse direction contact surface 68 are formed. Abut. Since the portion 520 on the radially inner side of the shaft 52 is located at a relatively close distance from the central axis CA65, the rotational torque acting on the impeller 65 is relatively small compared to the portion relatively far from the central axis CA65. The load acting on the impeller 65 due to the collision with the impeller 65 becomes relatively small. Therefore, the fuel pump 1 according to the first embodiment can prevent the impeller 65 from being damaged by the collision between the shaft 52 and the impeller 65 when the rotation direction of the shaft 52 is switched.

  When the position detection of the rotor 50 with respect to the stator 10 shown in FIG. 4B ends, the shaft 52 rotates in the positive direction R2 in order to pressurize the fuel. That is, the shaft 52 rotates from the position shown in FIG. 4B to the position shown in FIG. At this time, one surface 524 as the “shaft positive direction contact surface” of the shaft contact surface 523 contacts the impeller positive direction contact surface 69 of the impeller 65 formed in a flat shape. At this time, since one surface 524 of the shaft contact surface 523 formed in a flat shape and the impeller positive direction contact surface 69 formed in a flat shape are in contact with each other, the shaft contact surface 523 and the impeller are in contact with each other. The area in contact with the positive contact surface 69 is relatively large. Thereby, the surface pressure of the rotational torque of the shaft 52 acting on the impeller positive direction contact surface 69 is reduced. Therefore, the load acting on the impeller 65 becomes relatively small, and damage to the impeller 65 can be further prevented.

(Second Embodiment)
Next, a fuel pump according to a second embodiment of the present invention will be described with reference to FIG. The second embodiment is different 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.

  FIG. 5 shows an enlarged view of a main part of the impeller 75 provided in the fuel pump according to the second embodiment. The impeller 75 has a fitting hole 76, a radial direction of the impeller 75 so as to correspond to the through holes 751, 752, 753 that penetrate the impeller 75 in the axial direction of the fuel pump around the fitting hole 76, and the groove 63 and the groove 73. The outer end portion has inclined surfaces (not shown) provided at equal intervals in the circumferential direction.

  As shown in FIG. 5, the fitting hole 76 is connected to an arc surface 77 and an arc surface 77 whose cross-sectional shape is formed in an arc shape centering on the central axis CA75 of the impeller 75, and extends in the vertical direction from the arc surface 77. Impeller reverse direction contact surface 78 forming intersection line 771 and impeller reverse direction contact surface 78 connected to impeller reverse direction contact surface 78 while forming intersection line 772 connected to arc surface 77 and extending in the vertical direction with arc surface 77. An impeller positive direction contact surface 79 that forms an intersection line 766 with the contact surface 78 is formed. The fitting hole 76 is formed in a substantially D shape so that the cross-sectional shape thereof matches the cross-sectional shape of the end portion 522 of the shaft 52. The impeller reverse direction contact surface 78, the impeller positive direction contact surface 79, and the circular arc surface 77 are formed to extend in the vertical direction.

The impeller reverse direction contact surface 78 is composed of two planes. An impeller reverse direction first contact surface 781 is formed on the intersection line 766 side. An impeller reverse direction second contact surface 782 is formed on the intersection line 771 side. The impeller reverse direction first contact surface 781 and the impeller reverse direction second contact surface 782 form an intersection line 769.
When a virtual plane extending radially outward from the intersection line 766 through the impeller reverse direction first contact surface 781 is a virtual plane 767, the impeller reverse direction second contact surface 782 is directed from the intersection line 769 to the intersection line 771. Accordingly, the distance from the virtual plane 767 is formed in a direction away from the central axis CA75. At this time, the distance D3 between the intersection line 771 and the central axis CA75 is larger than the distance D5 between the circular arc surface 77 and the central axis CA75.

  The impeller positive direction contact surface 79 is formed in a flat shape. Specifically, as shown in FIG. 5, when a virtual plane that includes the intersection line 766 and is in contact with the impeller positive direction contact surface 79 in the vicinity of the intersection line 766 is a virtual plane 768, the impeller positive direction contact surface 79 is It is formed so as to be located on a virtual plane 768. At this time, the distance D4 between the intersection line 772 and the central axis CA75 is the same as the distance D5 between the circular arc surface 77 and the central axis CA75.

  In the fuel pump according to the second embodiment, the impeller reverse direction contact surface 78 includes two planes, an impeller reverse direction first contact surface 781 and an impeller reverse direction second contact surface 782. The impeller reverse direction second contact surface 782 is formed in a direction away from the central axis CA75 with respect to the impeller reverse direction first contact surface 781. Thereby, when the shaft 52 rotates in the reverse direction, the other surface 525 of the shaft 52 contacts the surface of the radially inner portion 520 and the impeller reverse direction first contact surface 781. Therefore, 2nd Embodiment has the same effect as 1st Embodiment.

  In the fuel pump according to the second embodiment, the impeller reverse direction contact surface 78 is composed of two planes. Thereby, the process of the fitting hole 76 becomes easy compared with 1st Embodiment, and the manufacturing man-hour of a fuel pump can be reduced.

(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 shaft and 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.

  The principal part enlarged view of the impeller 80 with which the fuel pump by 3rd Embodiment is provided is shown in FIG. The impeller 80 corresponds to the fitting hole 81, the through holes 811, 812, 813, and 814 that penetrate the impeller 80 in the axial direction of the fuel pump around the fitting hole 81, and the groove 63 and the groove 73. An inclined surface (not shown) provided at equal intervals in the circumferential direction is provided at the radially outer end.

  The shaft 82 provided in the fuel pump according to the third embodiment is formed so as to have two planes in which one end 822 fitted into the fitting hole 81 is formed substantially in parallel. As shown in FIG. 6, one end 822 has two shaft abutting surfaces 823 and 826, and the cross-sectional shape thereof is substantially I-shaped.

  As shown in FIG. 6, the fitting hole 81 is connected to two arcuate surfaces 83, 84, arcuate surface 83 having a cross-sectional shape formed in an arc shape centered on the central axis CA <b> 80 of the impeller 80. Impeller reverse contact surface 85 that forms intersection line 831 extending in the vertical direction, and arc surface 84 are connected to impeller reverse contact surface 85 while forming cross line 841 extending in the vertical direction to arc surface 84 and impeller. Impeller positive direction contact surface 86 that forms an intersection line 801 with the reverse direction contact surface 85, impeller reverse direction contact surface 87 that forms an intersection line 842 that extends in the vertical direction with the circular arc surface 84 connected to the arc surface 84, and an arc Impeller positive direction contact surface that is connected to the impeller reverse direction contact surface 87 and is connected to the impeller reverse direction contact surface 87 while forming an intersection line 832 extending in the vertical direction with the arc surface 83. 88. The fitting hole 81 is formed in a substantially I shape so that its cross-sectional shape matches the cross-sectional shape of one end portion 822 of the shaft 82. The impeller reverse direction contact surfaces 85 and 87, the impeller forward direction contact surfaces 86 and 88, and the arc surfaces 83 and 84 are formed to extend in the vertical direction, that is, in the direction of the central axis CA80 of the impeller 80. .

  The impeller reverse direction contact surface 85 is formed from a single curved surface, and as shown in FIG. 6, the cross-sectional shape is formed to be a curve that curves in the direction of the through hole 812 when viewed from a point on the intersection line 801. Has been. Specifically, if a virtual plane that includes the intersection line 801 and is in contact with the impeller reverse direction contact surface 85 in the vicinity of the intersection line 801 is a virtual plane 803, the impeller reverse direction contact surface 85 has a cross-sectional shape of the intersection line 801. From the virtual plane 803 to the direction opposite to the central axis CA80 side as it goes to the intersection line 831. At this time, the distance D6 between the intersection line 831 and the central axis CA80 is larger than the distance D10 between the arcuate surfaces 83 and 84 and the central axis CA80.

  The impeller positive direction contact surface 86 is formed in a flat shape so as to be in contact with one surface 821 as a “shaft positive direction contact surface” constituting the shaft contact surface 823. Specifically, as shown in FIG. 6, when a virtual plane that includes the intersection line 801 and contacts the impeller positive direction contact surface 86 in the vicinity of the intersection line 801 is a virtual plane 804, the impeller positive direction contact surface 86 is It is formed so as to be located on the virtual plane 804. At this time, the distance D7 between the intersection line 841 and the central axis CA80 is the same as the distance D10 between the arcuate surfaces 83 and 84 and the central axis CA80.

  The impeller reverse direction contact surface 87 is formed from a single curved surface, and as shown in FIG. 6, the cross-sectional shape is formed to be a curve that curves in the direction of the through hole 814 when viewed from a point on the intersection line 802. Has been. Specifically, assuming that a virtual plane that includes the intersection line 802 and is in contact with the impeller reverse direction contact surface 87 in the vicinity of the intersection line 802 is a virtual plane 805, the impeller reverse direction contact surface 87 has a cross-sectional shape of the intersection line 802. From the imaginary plane 805 to the direction opposite to the central axis CA80 side as it goes to the intersection line 842. At this time, the distance D8 between the intersection line 842 and the central axis CA80 is larger than the distance D10 between the arcuate surfaces 83 and 84 and the central axis CA80.

  The impeller positive direction contact surface 88 is formed in a flat shape so as to be in contact with one surface 829 as a “shaft positive direction contact surface” constituting the shaft contact surface 826. Specifically, as shown in FIG. 6, when a virtual plane that includes the intersection line 802 and contacts the impeller positive direction contact surface 88 near the intersection line 802 is a virtual plane 806, the impeller positive direction contact surface 88 is It is formed so as to be located on the virtual plane 806. At this time, the distance D9 between the intersection line 832 and the central axis CA80 is the same as the distance D10 between the arc surfaces 83 and 84 and the central axis CA80.

  In the fuel pump according to the third embodiment, when the shaft 82 rotates in the reverse direction, the other surface 825 as the “shaft reverse direction contact surface” and the shaft contact surface constituting the shaft contact surface 823 of the shaft 82. The other surface 828 as a “shaft reverse direction contact surface” constituting 826 contacts the impeller reverse direction contact surfaces 85 and 87. At this time, of the other surface 825, the surface of the radially inner portion 824 of the shaft 82 as “one radially inner portion of the shaft” and the impeller reverse direction abutting surface 85 abut, and the other surface A surface of a portion 827 on the radially inner side of the shaft 82 as “another portion on the radially inner side of the shaft” of 828 comes into contact with the impeller reverse direction contact surface 87. Thereby, 3rd Embodiment has the same effect as 1st Embodiment.

  In the fuel pump according to the third embodiment, the rotational torque of the shaft 82 acts on the impeller 80 via the two shaft contact surfaces 823 and 826. Thereby, the surface pressure of the rotational torque of the shaft 82 acting on the impeller 80 is reduced. Therefore, the load acting on the impeller 80 becomes relatively small, and damage to the impeller 80 can be further prevented.

(Fourth embodiment)
Next, a fuel pump according to a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment differs from the third embodiment in the shape of the impeller. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 3rd Embodiment, and description is abbreviate | omitted.

  The principal part enlarged view of the impeller 90 with which the fuel pump by 4th Embodiment is provided is shown in FIG. The impeller 90 corresponds to the fitting hole 91, the through holes 911, 912, 913, 914 passing through the impeller 90 in the axial direction of the fuel pump around the fitting hole 91, and the groove 63 and the groove 73. An inclined surface (not shown) provided at equal intervals in the circumferential direction is provided at the radially outer end.

  As shown in FIG. 7, the fitting hole 91 is connected to two arcuate surfaces 93, 94, arcuate surface 93 having a cross-sectional shape formed in an arc shape centered on the central axis CA <b> 90 of the impeller 90. Impeller reverse direction contact surface 95 forming an intersection line 931 extending in the vertical direction, and the arc surface 94 are connected to the impeller reverse direction contact surface 95 while forming an intersection line 941 extending in the vertical direction from the arc surface 94 to the impeller. An impeller forward contact surface 96 that forms an intersection line 901 with the reverse contact surface 95, an impeller reverse contact surface 97 that connects with the arc surface 94 and forms an intersection line 942 extending in the vertical direction with the arc surface 94, an arc Impeller positive direction contact surface that connects with the impeller reverse direction contact surface 97 and forms an intersection line 902 with the impeller reverse direction contact surface 97 while forming an intersection line 932 extending in the vertical direction with the arc surface 93. 98. The fitting hole 91 is formed in a substantially I shape so that its cross-sectional shape matches the cross-sectional shape of one end 922 of the shaft 92. The impeller reverse direction contact surfaces 95 and 97, the impeller forward direction contact surfaces 96 and 98, and the arc surfaces 93 and 94 are formed to extend in the vertical direction, that is, in the direction of the central axis CA90 of the impeller 90.

The impeller reverse direction contact surfaces 95 and 97 are each composed of two planes.
The impeller reverse direction contact surface 95 is formed with an impeller reverse direction first contact surface 951 on the intersection line 901 side. An impeller reverse direction second contact surface 952 is formed on the intersection line 931 side. The impeller reverse direction first contact surface 951 and the impeller reverse direction second contact surface 952 form an intersection line 950.
When a virtual plane extending radially outward from the intersection line 901 through the impeller reverse direction first contact surface 951 is a virtual plane 903, the impeller reverse direction second contact surface 952 is directed from the intersection line 850 to the intersection line 931. Accordingly, the distance from the virtual plane 903 is formed in a direction away from the central axis CA90. At this time, the distance D11 between the intersection line 931 and the central axis CA90 is greater than the distance D13 between the arcuate surfaces 93 and 94 and the central axis CA90.

The impeller reverse direction contact surface 97 is formed with an impeller reverse direction first contact surface 971 on the intersection line 902 side. An impeller reverse direction second contact surface 972 is formed on the intersection line 942 side. The impeller reverse direction first contact surface 971 and the impeller reverse direction second contact surface 972 form an intersection line 970.
When a virtual plane extending radially outward from the intersection line 902 through the impeller reverse direction first contact surface 971 is a virtual plane 904, the impeller reverse direction second contact surface 972 is directed from the intersection line 970 to the intersection line 942. Accordingly, the distance from the virtual plane 904 is formed in a direction away from the central axis CA90. At this time, the distance D12 between the intersection line 942 and the central axis CA90 is larger than the distance D13 between the arcuate surfaces 93 and 94 and the central axis CA90.

  In the fuel pump according to the fourth embodiment, the impeller reverse direction contact surfaces 95 and 97 are each composed of two planes. The impeller reverse direction second contact surface 952 constituting the impeller reverse direction contact surface 95 is formed in a direction away from the central axis CA90. Further, the impeller reverse direction second contact surface 972 constituting the impeller reverse direction contact surface 97 is formed in a direction away from the central axis CA90. Thus, when the shaft 92 rotates in the reverse direction, the other surface 825 of the shaft 92 is such that the surface of the radially inner portion 824 of the other surface 825 and the impeller reverse direction first contact surface 951 are the same. Abut. In addition, the other surface 828 of the shaft 92 is in contact with the surface of the other surface 828 in the radially inner portion 827 and the impeller reverse direction first contact surface 971. Therefore, the fourth embodiment has the same effect as the third embodiment.

  Further, in the fuel pump according to the fourth embodiment, the impeller reverse direction contact surfaces 95 and 97 are each composed of two planes. Thereby, the process of the fitting hole 91 becomes easy compared with 3rd Embodiment, and the manufacturing man-hour of a fuel pump can be reduced.

(Other embodiments)
(A) In the above-described embodiment, the fitting hole is an impeller reverse direction contact surface, an impeller positive direction contact surface, and an arc surface connecting them. However, the inner wall surface of the impeller that forms the fitting hole is not limited to this. It may be formed only on the impeller reverse direction contact surface and the arc surface, or may be formed only on the impeller forward direction contact surface and the arc surface. Moreover, it may not be a circular arc surface.

  (A) In the above-described embodiment, the shaft contact surface is formed in a flat shape. However, the shape of the shaft contact surface is not limited to this. For example, one surface constituting the shaft contact surface and the other surface may be connected at an angle other than 180 °.

  (C) In the first and third embodiments, the impeller reverse direction contact surface is a line of intersection between the impeller reverse direction contact surface and the impeller positive direction contact surface and the impeller reverse direction contact surface and the arc surface. It is assumed that it is formed so as to be away from the imaginary plane in the direction opposite to the central axis side of the impeller as it goes toward. However, the shape of the impeller reverse direction contact surface is not limited to this. The impeller reverse direction contact surface is formed in a flat shape, the other surface of the shaft contact surface that contacts the impeller reverse direction contact surface is formed in a curved shape, and when the shaft rotates in the reverse direction, May contact the impeller reverse direction contact surface.

  (D) In the first and third embodiments, the impeller reverse direction contact surface is formed from one curved surface. However, the configuration of the impeller reverse direction contact surface is not limited to this. You may form from the structure of a some curved surface.

  (E) In the above-described embodiment, the motor unit included in the fuel pump is a brushless motor. However, the motor need not be a brushless motor as long as the motor can rotate the shaft in two directions, the forward direction and the reverse direction.

  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 ... Fuel pump,
10: Stator,
20 ・ ・ ・ Housing (pump case),
38 ・ ・ ・ Connection terminal,
40 ... Cover end (pump case),
50 ... rotor,
52, 82 ... Shaft,
520, 824, 827 ... radially inner part,
60 ・ ・ ・ Pump cover (pump case),
65, 75, 80, 90 ... impeller,
66, 76, 81, 91 ... fitting hole,
R1 ... reverse direction,
R2: Positive direction.

Claims (5)

A pump case (20, 40, 60) having a suction port (61) for sucking fuel and a discharge port (41) for discharging fuel;
A cylindrical stator (10) wound with a plurality of windings and housed inside the pump case;
A rotor (50) rotatably provided on the radially inner side of the stator;
Shafts (52, 82) provided coaxially with the rotor and rotating integrally with the rotor;
The shaft has fitting holes (66, 76, 81, 91) into which one end (522, 922) of the shaft is fitted, and when the shaft rotates, the fuel sucked from the suction port is pressurized and the discharge port Impellers (65, 75, 80, 90) discharged from
With
When the shaft rotates in the reverse direction (R1), which is the direction opposite to the forward direction (R2), which is the direction in which the impeller rotates when the impeller pressurizes the fuel, the portion (520 in the radial direction of the shaft) 824, 827) and the impeller abut against each other. The shaft has a shaft reverse contact surface (525) formed in a planar shape at the one end,
The impeller has an impeller reverse direction abutting surface (68, 78) composed of a curved surface or a plurality of planes forming the fitting hole,
When the shaft rotates in the reverse direction, the surface of the shaft reverse contact surface on the radially inner side of the shaft (520) and the impeller reverse contact surface come into contact with each other. The fuel pump according to 1. The shaft has a plurality of shaft reverse contact surfaces (825, 828) formed in a planar shape at the one end,
The impeller has a plurality of impeller reverse direction abutting surfaces (85, 87, 95, 97) configured from a curved surface or a plurality of planes forming the fitting hole,
When the shaft rotates in the reverse direction, the surface of one portion (824) radially inward of the shaft opposite to the one shaft reverse contact surface and the one impeller reverse contact surface are in contact with each other. The surface of another portion (827) radially inside the shaft of the other shaft reverse contact surface is in contact with the other impeller reverse contact surface. The fuel pump described. The shaft has a shaft positive direction contact surface (524, 821, 829) formed in a planar shape at the one end,
The impeller has an impeller positive direction contact surface (69, 79, 86, 88, 96, 98) that is formed in a planar shape and forms the fitting hole,
4. The fuel pump according to claim 1, wherein when the shaft rotates in the forward direction, the shaft forward contact surface and the impeller forward contact surface come into contact with each other. 5. A pump case (20, 40, 60) having a suction port (61) for sucking fuel inside and a discharge port (41) for discharging fuel to the outside;
A cylindrical stator (10) wound with a plurality of windings and housed inside the pump case;
A rotor (50) rotatably provided on the radially inner side of the stator;
A shaft (52) provided coaxially with the rotor and rotating integrally with the rotor;
An impeller (65) that has a fitting hole (66) into which one end (522) of the shaft is fitted, pressurizes the fuel flowing in from the suction port when the shaft rotates, and discharges the fuel from the discharge port; ,
With
The shaft has a shaft positive contact surface (524, 825) formed in a planar shape at one end,
The impeller has a flat impeller positive contact surface (69, 79, 86, 96) that forms the fitting hole,
When the shaft rotates in the forward direction, the shaft positive direction contact surface and the impeller positive direction contact surface contact each other.

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