JP6135593B2 - Fuel pump - Google Patents

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 discloses a fuel pump including an impeller having a fitting hole that is formed to have a D-shaped cross-section and to which a motor shaft is fitted, and a hole to which a weight for correcting the weight distribution of the impeller is attached. Have been described.

Japanese Patent Laid-Open No. 11-082208

  In a fuel pump using a brushless motor as a motor, the shaft has two directions: a forward direction in which the impeller rotates to pressurize the fuel, and a reverse direction in which the rotor rotates to detect the position of the rotor relative to the stator. Rotate to. Since there is a manufacturing tolerance in the fitting hole of the impeller, a gap is formed between the inner wall that forms the fitting hole and the side wall that forms one end of the shaft that fits into the fitting hole. Yes. When one end of the shaft shifts from a state in which it can rotate in the forward or reverse direction to a state in which it can rotate in the reverse or forward direction, the shaft rotates in the fitting hole. The rotating torque of the rotating shaft acts on one contact surface that forms the fitting hole. For this reason, there exists a possibility that an impeller may be damaged.

  Also, in order to reduce the surface pressure of the rotational torque acting on the impeller, the cross-sectional shape of the fitting hole and the cross-sectional shape of one end of the shaft are I-shaped, and two abutments that one end of the shaft has 2. Description of the Related Art There is known a fuel pump whose surface abuts simultaneously on two abutting surfaces formed as inner walls of a fitting hole. However, in an impeller molded by injection molding, it is difficult to process the impeller so that the two abutment surfaces of the impeller can simultaneously abut against the two abutment surfaces of the shaft. Therefore, when the shaft abuts on the impeller, only one of the two abutment surfaces of the shaft abuts on the impeller, and the 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 having a pump chamber communicating with a suction port and a discharge port, a stator, a rotor, a shaft provided coaxially with the rotor and rotating integrally with the rotor, and rotatably accommodated in the pump chamber. The shaft has a fitting hole to which one end of the shaft is fitted, and the shaft is provided so as to be relatively movable in the circumferential direction within the clearance range of the fitting hole. When the shaft rotates, the fuel sucked from the suction port is pressurized. An impeller that discharges from a discharge port, wherein the shaft has a shaft-side contact surface that can contact the impeller at one end, and the fitting hole is formed on the shaft-side contact surface. provided at opposite positions are formed from the impeller side contact surface capable of contacting the shaft side contact surface, the impeller is formed in the radially outer side of the fitting hole through the impeller in the direction of the center axis of the impeller shaft side The contact surface and the impeller-side abutment surface is characterized by having a deformation allowing space for deforming the contact.

In the fuel pump of the present invention, the shaft and the impeller are formed so that the shaft rotates integrally with the impeller while the first contact surface on the shaft side or the second contact surface on the shaft side and the contact surface on the impeller side are in contact. Has been. When the impeller rotates with the shaft, the shaft-side first contact surface or the shaft-side second contact surface and the impeller-side contact surface are not correct depending on the processing accuracy of the fitting hole and the position of the shaft with respect to the fitting hole. May come into contact. In the impeller included in the fuel pump of the present invention, when the shaft-side first contact surface or the shaft-side second contact surface and the impeller-side contact surface come into contact with each other, the deformation allowable space is deformed by the force acting on the impeller from the shaft. To do. When the deformation allowable space is deformed, the amount of elastic deformation of the impeller is increased, so that the shape of the fitting hole is deformed, and the shaft-side second contact surface or the shaft-side first contact surface correctly contacts the impeller-side contact surface. Touch. Thus, in the fuel pump of the present invention, the shaft-side first contact surface and the shaft-side second are not affected by the processing accuracy of the fitting hole and the position of the shaft with respect to the fitting hole, but by the deformation of the deformation-permissible space . The contact surface and the impeller side contact surface can be correctly contacted. As a result, the surface pressure acting on the impeller when the shaft rotates is reduced, and the impeller can be prevented from being damaged.

It is sectional drawing of the fuel pump by 1st Embodiment of this invention. It is a top view of the impeller of the fuel pump by 1st Embodiment of this invention. It is a schematic diagram explaining the effect | action of the fuel pump by 1st Embodiment of this invention. It is a top view of the impeller of the fuel pump by 2nd Embodiment of this invention. It is a top view of the impeller of the fuel pump by 3rd Embodiment of this invention. It is a top view of the impeller of the fuel pump by 4th Embodiment of this invention. It is a top view of the impeller 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 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 end portion 522 of the shaft 52 extends in the vertical direction and is formed in a planar shape with respect to the shaft first plane 523 as a “shaft side first contact surface”, and the planarly formed shaft first plane 523. A shaft second flat surface 524 is provided as a “shaft side second contact surface” provided substantially in parallel. In addition, the end portion 522 of the shaft 52 connects the one side of the shaft first plane 523 and the one side of the shaft second plane 524, and the shaft first curved surface 525 formed in a curved shape, and the shaft first It has a shaft second curved surface 526 that connects the other side of the plane 523 and the other side of the shaft second plane 524 and is formed into a curved surface. Thereby, the cross-sectional shape in the direction perpendicular to the rotation axis CA52 of the end portion 522 of the shaft 52 is substantially I-shaped.

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 as a “pump case” , 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 is formed in the center of the pump casing 70 so as to penetrate the pump casing 70 in the plate thickness direction. 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 is formed in the approximate center of the impeller 65. The fitting hole 66 is formed in a substantially I shape so that the cross-sectional shape thereof matches the cross-sectional shape of the end portion 522 of the shaft 52. The end portion 522 of the shaft 52 is fitted into 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 impeller 65 will be described later.

  The impeller 65 has a plurality of inclined surfaces 64 formed at positions corresponding to the grooves 63 and 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 an intermediate chamber 75 formed between the pump casing 70 and the motor unit 3.

  The fuel guided to the intermediate chamber 75 is a fuel passage 77 between the rotor 50 and the stator 10, a fuel passage 78 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 79. The fuel guided to the intermediate chamber 75 passes through a fuel passage 76 formed between the inner wall of the housing 20 and the outer wall of the stator 10. The fuel passing through the fuel passages 76, 77, 78 and 79 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 impeller 65. Here, the detailed shape of the impeller 65 will be described with reference to FIGS. FIG. 2 is a top view of the impeller 65. FIG. 3 is a schematic diagram showing the positional relationship between the fitting hole 66 and the shaft 52 when the fuel pump 1 is driven. 3B to 3D, the shape of the fitting hole 66 is exaggerated from the actual shape for convenience of explanation.

  The impeller 65 has a fitting hole 66, an impeller first flat surface 661 as “impeller side first contact surface”, an impeller second flat surface 662 as “impeller side second contact surface”, and “fitting hole first”. The impeller first curved surface 663 as a “formation surface” and the impeller second curved surface 664 as a “fitting hole second formation surface”.

  The impeller first plane 661 is a plane formed so as to extend in the direction of the central axis CA66 of the fitting hole 66. The impeller first plane 661 is provided at a position facing the shaft first plane 523 and can contact the shaft first plane 523 when the shaft 52 rotates.

  The impeller second plane 662 is a plane formed so as to extend in the direction of the central axis CA66. The impeller second plane 662 is provided substantially parallel to the impeller first plane 661. The impeller second plane 662 is provided at a position facing the shaft second plane 524 and can contact the shaft second plane 524 when the shaft 52 rotates.

  The impeller first curved surface 663 connects one side parallel to the central axis CA66 of the impeller first plane 661 and one side parallel to the central axis CA66 of the impeller second plane 662. The impeller first curved surface 663 is formed so that the cross-sectional shape thereof is a substantially arc shape that protrudes radially outward from a point on the central axis CA66. The impeller first curved surface 663 is formed with a first groove 665 as a “deformation allowance space” substantially at the center.

  The impeller second curved surface 664 connects the other side parallel to the central axis CA66 of the impeller first plane 661 and the other side parallel to the central axis CA66 of the impeller second plane 662. The impeller second curved surface 664 is formed so that the cross-sectional shape is a substantially arc shape that protrudes radially outward from a point on the central axis CA66. The impeller second curved surface 664 is formed with a second groove 666 as a “deformation allowance space” substantially at the center.

The first groove 665 is formed in a slit shape so as to extend radially outward from the impeller first curved surface 663. The first groove 665 is formed to communicate with the fitting hole 66 and penetrates the impeller 65 in the direction of the central axis CA66.
The second groove 666 is formed in a slit shape so as to extend radially outward from the impeller second curved surface 664. The second groove 666 is formed to communicate with the fitting hole 66 and penetrates the impeller 65 in the direction of the central axis CA66.
The first groove 665 and the second groove 666 are formed so as to extend in opposite directions and have the same radial length.

  Here, the operation and effect of the fuel pump 1 according to the first embodiment will be described with reference to FIG.

  In the fuel pump 1 according to the first embodiment, as shown in FIG. 3A, when the shaft first plane 523 formed in the shaft 52 and the impeller first plane 661 forming the fitting hole 66 are parallel to each other. The positional relationship between the shaft second plane 524 formed on the shaft 52 and the impeller second plane 662 forming the fitting hole 66 is preferably parallel. However, since the impeller 65 formed from resin by injection molding is difficult to be molded so as to satisfy these relationships, for example, when the shaft first plane 523 and the impeller first plane 661 are parallel, the shaft second In some cases, the plane 524 and the impeller second plane 662 are not parallel to each other.

  For example, as shown in FIG. 3B, the shaft first plane 523 and the impeller first plane 661 are parallel, but the shaft second plane 524 and the impeller second plane 662 are in a parallel positional relationship. In some cases, the fitting hole 66 may be formed such that the intersection line 667 between the impeller second plane 662 and the impeller second curved surface 664 is located away from a point on the center axis CA66 of the fitting hole 66.

In the case of the shape of the fitting hole 66 as shown in FIG. 3 (b), as shown in FIG. 3 (c), when the shaft 52 rotates in the direction R1 indicated by the solid line arrow, the shaft first While the plane 523 and the impeller first plane 661 abut, the shaft second plane 524 and the impeller second plane 662 are separated from each other. The shaft 52 and the impeller 65 further rotate in the direction R1 in this state. At this time, the acting force F1 acts between the shaft first plane 523 and the impeller first plane 661 in a direction from the shaft first plane 523 toward the impeller first plane. The impeller 65 is deformed by the acting force F1 so that the first groove 665 is expanded as shown in FIG. Due to the deformation of the first groove 665, the shape of the fitting hole 66 is changed and the shaft second plane 524 and the impeller second plane 662 which are separated from each other come into contact with each other. In FIG. 3D, the shapes of the fitting hole 66 and the first groove 665 before the first groove 665 is deformed are indicated by dotted lines.
Here, it has been described that the two flat surfaces of the shaft 52 abut on the two flat surfaces of the impeller 65 by the expansion of the first groove 665, but the same applies to the second groove 666.

  (A) In the fuel pump 1 according to the first embodiment, either the impeller first plane 661 or the impeller second plane 662 in which the shaft 52 rotates in the fitting hole 66 and the shaft 52 forms the fitting hole 66. When the first groove 665 or the second groove 666 is brought into contact with the first hole 660, the shape of the fitting hole 66 is changed. When the shape of the fitting hole 66 changes, the shaft second plane 524 or the shaft first plane 523 of the shaft 52 abuts on the impeller second plane 662 or the impeller first plane 661 on which the shaft 52 does not abut, and the shaft 52 Two planes contact the inner wall of the fitting hole 66. Thereby, the rotational torque of the shaft 52 acts on both the impeller first plane 661 and the impeller second plane 662, and the surface pressure of the rotational torque acting on the impeller 65 is reduced. Therefore, the surface pressure acting on the impeller 65 becomes relatively small, and the impeller 65 can be prevented from being damaged by the rotational torque of the shaft 52.

  (B) In the fuel pump 1 according to the first embodiment, when the impeller 65 is formed by injection molding, the parallelism of the impeller first plane 661 with respect to the shaft first plane 523 and the impeller with respect to the shaft second plane 524 It is not necessary to strictly manage the parallelism of the second plane 662. Thereby, the two planes of the shaft 52 can abut against the two planes forming the fitting hole 66 while reducing the number of manufacturing steps of the fuel pump 1. Therefore, the manufacturing cost of the fuel pump 1 can be reduced.

  (C) The first groove 665 and the second groove 666 are formed at the center of the impeller first curved surface 663 and the impeller second curved surface 664 that face each other. Further, the first groove 665 and the second groove 666 are formed to extend the same length in opposite directions when viewed from the central axis CA66. As a result, when the rotational torque of the shaft 52 acts on the impeller first plane 661 or the impeller second plane 662, the impeller 65 is deformed into a similar shape, so that stress is concentrated on a specific part of the impeller 65. Can be prevented. Therefore, the impeller 65 can be prevented from being damaged by the rotational torque of the shaft 52.

(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. 4 shows a top view of the impeller 67 provided in the fuel pump according to the second embodiment. A fitting hole 68 is formed in the approximate center of the impeller 67. The end portion 522 of the shaft 52 is fitted into the fitting hole 66.

  The fitting hole 68 is formed in a substantially I shape so that the cross-sectional shape thereof matches the cross-sectional shape of the end portion 522 of the shaft 52. The fitting hole 68 includes an impeller first flat surface 681 as an “impeller side first contact surface”, an impeller second flat surface 682 as an “impeller side second contact surface”, a “fitting hole forming surface”, and a “fitting surface”. An impeller first curved surface 683 as a “fitting hole first forming surface”, an impeller second curved surface 684 as a “fitting hole forming surface”, and an “fitting hole second forming surface”.

  The impeller first plane 681 is a plane formed to extend in the direction of the central axis CA67 of the fitting hole 68. The impeller first plane 681 is provided at a position facing the shaft first plane 523 and can contact the shaft first plane 523 when the shaft 52 rotates.

  The impeller second plane 682 is a plane formed to extend in the direction of the central axis CA67. The impeller second plane 682 is provided substantially parallel to the impeller first plane 681. The impeller second plane 682 is provided at a position facing the shaft second plane 524, and can contact the shaft second plane 524 when the shaft 52 rotates.

  The impeller first curved surface 683 connects one side parallel to the central axis CA67 of the impeller first plane 681 and one side parallel to the central axis CA67 of the impeller second plane 682. The impeller first curved surface 683 is formed so that the cross-sectional shape is a substantially arc shape that protrudes radially outward from a point on the central axis CA67. The impeller first curved surface 683 is formed with a first groove 685 as a “deformation allowable space” substantially at the center.

  The impeller second curved surface 684 connects another side parallel to the central axis CA67 of the impeller first plane 681 and another side parallel to the central axis CA67 of the impeller second plane 682. The impeller second curved surface 684 is formed so that the cross-sectional shape is a substantially arc shape that protrudes radially outward from a point on the central axis CA67. The impeller second curved surface 684 is formed with a second groove 686 as a “deformation allowance space” substantially at the center.

  The first groove 685 is formed in a slit shape so as to extend radially outward from the impeller first curved surface 683. The first groove 685 is formed to communicate with the fitting hole 68 and penetrates the impeller 67 in the direction of the central axis CA67. The second groove 686 is formed in a slit shape so as to extend radially outward from the impeller second curved surface 684. The second groove 686 is formed to communicate with the fitting hole 68 and penetrates the impeller 67 in the direction of the central axis CA67.

  The first groove 685 and the second groove 686 are formed to extend in opposite directions and have the same radial length. At this time, a virtual circle VL64 having a center on the central axis CA67 and connecting radially inner portions of the plurality of inclined surfaces 64 of the impeller 67 is defined as a virtual circle VL64, and the impeller first curved surface 683 having the center on the central axis CA67. When the virtual circle passing on the impeller second curved surface 684 is a virtual circle VL68, the radially outer wall surface 687 forming the first groove 685 and the radially outer wall surface 688 forming the second groove 686 are shown in FIG. As shown, it is formed in the radially inward direction from the intermediate virtual circle VL67 that is equidistant (distance D2 in FIG. 4) from the virtual circle VL64 and the virtual circle VL68.

  In the fuel pump according to the second embodiment, the first groove 685 and the second groove 686 are formed radially inward from the intermediate virtual circle VL67. Thereby, the impeller 67 can be appropriately deformed by the action from the shaft 52. Therefore, the fuel pump according to the second embodiment has the same effects as the first embodiment, and has a larger deformation allowance than the first embodiment, and can further prevent the impeller 67 from being damaged by the rotational torque of the shaft 52. it can.

(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.

In the fuel pump according to the third embodiment, the impeller 85 has an inclined surface 84, a fitting hole 86, and a through hole 87 as a “deformation allowable space”.
A plurality of inclined surfaces 84 are formed at positions corresponding to the grooves 63 and the grooves 73 in the same manner as the inclined surface 64 of the first embodiment.
Similar to the fitting hole 66 of the first embodiment, the fitting hole 86 is formed in a substantially I shape so that its cross-sectional shape matches the cross-sectional shape of the end portion 522 of the shaft 52. The fitting hole 86 includes an impeller first flat surface 861 as an “impeller side first contact surface” capable of contacting the shaft first plane 523 and an “impeller side second contact” capable of contacting the shaft second plane 524. It is formed from an impeller second plane 862 as a “plane”.

  The through hole 87 is formed to extend in the direction of the central axis CA85, and penetrates the impeller 85 in the direction of the central axis CA85. In the fuel pump according to the second embodiment, six through-holes 87 are provided, and are equidistantly arranged on a circumference centered on a point on the central axis CA85 of the fitting hole 86 in the radially outward direction of the fitting hole 86. positioned. Further, one through hole 87 is provided so as to be point symmetric with respect to the other through holes with respect to a point on the central axis CA85.

  In the fuel pump according to the third embodiment, when the shaft 52 rotates in the fitting hole 86 of the impeller 85, only one of the shaft first plane 523 and the shaft second plane 524 of the shaft 52 is the fitting hole. In some cases, it may abut against the inner wall forming 86. In this case, the shape of the fitting hole 86 changes due to the deformation of the through hole 87, and the plane that is not in contact with the two planes of the shaft 52 contacts the inner wall that forms the fitting hole 86. Thereby, the fuel pump according to the second embodiment has the same effects as the effects (a) and (b) of the first embodiment.

  Further, the plurality of through holes 87 are equally spaced on a circumference centered on a point on the central axis CA85, and one through hole of the through hole 87 is another point with a point on the central axis CA85 as a symmetric point. It is provided so as to be point-symmetric with respect to the through hole. As a result, when the rotational torque of the shaft 52 acts on the impeller first plane 661 or the impeller second plane 662, the impeller 65 is deformed into a similar shape, so that a force acts on a specific part of the impeller 65. Can be prevented. Therefore, the impeller 65 can be prevented from being damaged by the rotational torque of the shaft 52.

(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.

  A top view of the impeller 88 provided in the fuel pump according to the fourth embodiment is shown in FIG. The impeller 88 has an inclined surface 84, a fitting hole 86, and a through hole 89 as a “deformation allowable space”.

  The through hole 89 is formed to extend in the direction of the central axis CA88 and penetrates the impeller 88 in the direction of the central axis CA88. In the fuel pump according to the fourth embodiment, six through-holes 89 are provided, and are equidistantly arranged on a circumference centered on a point on the central axis CA88 of the fitting hole 86 in the radially outward direction of the fitting hole 86. positioned.

  Further, a virtual circle having a center on the central axis CA88 and connecting the radially inner portions of the plurality of inclined surfaces 84 formed on the radially outer side of the impeller 88 is referred to as a virtual circle VL84, and the center is located on the central axis CA88. When a virtual circle passing through the impeller first curved surface 863 as the “fitting hole forming surface” and the impeller second curved surface 864 as the “fitting hole forming surface” of the fitting hole 86 is defined as a virtual circle VL86, the through hole As shown in FIG. 6, 89 is formed radially inward from the intermediate virtual circle VL88 located at the same distance (distance D4 in FIG. 6) from the virtual circle VL84 and the virtual circle VL86.

  In the fuel pump according to the fourth embodiment, the through hole 89 is formed radially inward from the intermediate virtual circle VL88. Thereby, the impeller 88 can be appropriately deformed by the action from the shaft 52. Therefore, the fuel pump according to the fourth embodiment has the same effect as that of the third embodiment, has a larger deformation allowable amount than the third embodiment, and can further prevent the impeller 88 from being damaged by the rotational torque of the shaft 52. it can.

(Fifth embodiment)
Next, a fuel pump according to a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment differs from the third embodiment in the shape of the end 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 3rd Embodiment, and description is abbreviate | omitted.

  A top view of the impeller 95 provided in the fuel pump according to the fifth embodiment is shown in FIG. The impeller 95 includes an inclined surface 94, a fitting hole 96, and through holes 991, 992, 993, 994 and 995 as “deformation allowable spaces”.

  A plurality of inclined surfaces 94 are formed at positions corresponding to the grooves 63 formed in the pump cover 60 and the grooves 73 formed in the pump casing 70.

The fitting hole 96 is formed in a substantially D shape so that its cross-sectional shape matches the cross-sectional shape of one end 922 of the shaft 92. The fitting hole 96 includes an impeller third plane 961 as an “impeller side third abutment surface” that can abut on a shaft third plane 923 as a “shaft side third abutment surface”, and a shaft third plane 923. sectional shape substantially parallel across the center axis CA95 is formed from the impeller curved 963 as a "fitting hole formation surface" formed as along the cie Yafuto third curved 925 to connect with a substantially arc-shaped curved surface.

  The through holes 991, 992, 993, 994, 995 are formed so as to extend in the direction of the central axis CA95, and pass through the impeller 85 in the direction of the central axis CA95. In the fuel pump according to the fifth embodiment, the impeller 95 has five through holes. The through holes 991, 992, 993, 994, and 995 are located at equal intervals on the circumference centering on a point on the central axis CA 95 of the fitting hole 96 in the radially outward direction of the fitting hole 96. Of the through holes of the impeller 95, two through holes 992 and 995 are provided in the vicinity of portions 962 and 964 where the impeller third plane 961 and the impeller curved surface 963 are connected.

Further, a virtual circle connecting the radially inner portions of the plurality of inclined surfaces 94 has a center on the center axis CA95 and imaginary circle VL94, virtual through the impeller La song surface 963 above has a center on the center axis CA95 Assuming that the circle is a virtual circle VL96, the through holes 991, 992, 993, 994, 995 are located at the same distance from the virtual circle VL94 and the virtual circle VL96 (distance D5 in FIG. 7) as shown in FIG. It is formed radially inward from the virtual circle VL98.

  In the fuel pump according to the fifth embodiment, the impeller 95 is formed such that the fitting hole 96 has a D-shaped cross section with respect to the end of the shaft 92 having a D-shaped cross section. At this time, an odd number of five through holes of the impeller 95 are formed in accordance with the shape of the fitting hole 96. Thus, even if the shape of the fitting hole into which the end portion of the shaft is fitted differs from the I-shape that abuts on both sides, the shaft third plane 923 is the impeller third plane 961 even if it is a D-shape that abuts only on one side. The impeller 95 can be deformed so as to abut against. Therefore, 5th Embodiment has the same effect as 3rd Embodiment.

  Further, in the fuel pump according to the fifth embodiment, the through holes 991, 992, 993, 994, 995 are formed radially inward from the intermediate virtual circle VL98. Thereby, the impeller 95 can be appropriately deformed by the action from the shaft 52. Therefore, the fuel pump according to the fifth embodiment can further prevent the impeller 95 from being damaged by the rotational torque of the shaft 92.

  Further, five through holes are formed in the impeller 95 in accordance with the shape of the fitting hole 96. As a result, the overall weight balance of the impeller 95 can be kept even, and problems such as vibrations can be prevented from occurring when the impeller 95 rotates.

(Other embodiments)
(A) In the first and second embodiments, the first groove and the second groove are provided as the “deformable space”. In the third, fourth, and fifth embodiments, a plurality of through-holes as “deformation allowable spaces” are provided. However, the shape of the “deformable space” is not limited to this. Any space provided on the impeller and capable of being deformed so as to increase the amount of elastic deformation of the impeller when the shaft and the impeller contact each other may be used.

  (A) In the above-described embodiment, the shaft first plane as the “shaft side first contact surface”, the shaft second plane as the “shaft side second contact surface”, and the “impeller side first contact surface” The impeller first plane as the impeller second plane as the “impeller side second contact surface” is formed in a planar shape. However, these surfaces do not have to be formed flat. It may be on a curved surface, and the “shaft side first contact surface” and the “impeller side first contact surface” can contact each other, and the “shaft side second contact surface” and the “impeller side second contact” What is necessary is just to form so that a contact surface "can contact | abut.

  (C) In the above-described embodiment, the shaft first plane as the “shaft side first contact surface” and the shaft second plane as the “shaft side second contact surface” are formed substantially in parallel. did. However, it does not have to be parallel.

  (D) In the first and second embodiments, a plurality of “deformable spaces” are formed. However, it may be one.

  (E) In the first and second embodiments, the first groove and the second groove are formed at the center of the impeller first curved surface and the impeller second curved surface. However, the place where the first groove and the second groove are formed is not limited to this.

  (F) In the first and second embodiments, the first groove and the second groove have the same radial length and are formed to extend in opposite directions. However, the relationship between the first groove and the second groove is not limited to this.

  (G) In the third, fourth, and fifth embodiments, the plurality of through holes are provided at equal intervals on a circumference centered on a point on the central axis of the impeller, and are arranged symmetrically with respect to each other. However, the place where the plurality of through holes are arranged is not limited to this.

  (H) In the third and fourth embodiments, six through holes are formed. In the fifth embodiment, five through holes are formed. Thus, when the shape of the fitting hole of the impeller is I-shaped, it is desirable to form an even number. Moreover, when the shape of the fitting hole which an impeller has is D shape, it is desirable to form an odd number. However, the number of through holes formed is not limited to this.

  (K) 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 rotates 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,
52, 92 ... Shaft,
523 ... shaft first plane (first contact surface sheet Yafuto side)
524 ... shaft second plane (second contact surface sheet Yafuto side)
923 ... Shaft third plane (third contact surface sheet Yafuto side)
65 ・ ・ ・ Impeller,
66, 68, 86, 96 ... fitting holes,
661, 681 ... impeller first plane (impeller side contact surface, impeller side first contact surface),
662, 682... Impeller second plane (impeller side contact surface, impeller side second contact surface),
961 ... Impeller third plane (impeller side contact surface, impeller side third contact surface),
665, 685... First groove (deformable space),
666, 686 ... second groove (deformable space),
87, 89, 991, 992, 993, 994, 995... Through-hole (deformable space).

Claims (6)

Pump case (20, 40, 60, 70) having a suction port (61) for sucking fuel, a discharge port (41) for discharging fuel, and a pump chamber (72) communicating with the suction port and the discharge port )When,
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, 92) provided coaxially with the rotor and rotating integrally with the rotor;
There is a fitting hole (66, 68, 86, 96) that is rotatably accommodated in the pump chamber and into which one end (522, 922) of the shaft is fitted, and the shaft is the fitting hole. An impeller (65, 67, 85, 88, 95) that is provided so as to be relatively movable in the circumferential direction within a clearance range in the above, and pressurizes fuel sucked from the suction port and discharges from the discharge port when rotated together with the shaft;
With
The shaft has a shaft side contact surface (523, 524, 923) capable of contacting the impeller at one end,
The fitting hole is formed from an impeller side contact surface (661, 662, 681, 682, 961) provided at a position facing the shaft side contact surface and capable of contacting the shaft side contact surface,
The impeller is formed in a radially outward direction of the fitting hole, passes through the impeller in a central axis direction of the impeller, and deforms when the shaft-side contact surface and the impeller-side contact surface come into contact with each other. (665, 666, 685, 686, 87, 89, 991, 992, 993, 994, 995). The shaft is formed at a position different from the shaft side first contact surface (523) as the shaft side contact surface capable of contacting the impeller and the shaft side first contact surface. A shaft-side second contact surface (524) as the shaft-side contact surface capable of contact;
The fitting hole is provided at a position facing the shaft-side first contact surface, and the impeller-side first contact surface as the impeller-side contact surface capable of contacting the shaft-side first contact surface ( 661, 681), and the impeller side second abutment surface as the impeller side abutment surface provided at a position facing the shaft side second abutment surface and capable of abutting against the shaft side second abutment surface (662, 682),
The deformation allowable space is deformed when the shaft-side first contact surface and the impeller-side first contact surface, or the shaft-side second contact surface and the impeller-side second contact surface contact each other. The fuel pump according to claim 1. The shaft is formed at a position different from the shaft side first contact surface (523) as the shaft side contact surface capable of contacting the impeller and the shaft side first contact surface. A shaft-side second contact surface (524) as the shaft-side contact surface capable of contact;
The fitting hole is provided at a position facing the shaft-side first contact surface, and the impeller-side first contact surface as the impeller-side contact surface capable of contacting the shaft-side first contact surface ( 861), and an impeller-side second contact surface (862) as the impeller-side contact surface provided at a position facing the shaft-side second contact surface and capable of contacting the shaft-side second contact surface. )
The even number of deformation permissible spaces are formed, and the shaft side first contact surface and the impeller side first contact surface, or the shaft side second contact surface and the impeller side second contact surface are formed. Deforms when abutting,
One deformation allowing space of a plurality of the deformation allowing space, the center axis (CA85, CA88) position of point symmetry of symmetrical point a point on the impeller to another modification allowing space for a plurality of the deformation allowing space The fuel pump according to claim 1 , wherein the fuel pump is formed as follows. The shaft has a shaft side third contact surface (923) as the shaft side contact surface capable of contacting the impeller,
The fitting hole is provided at a position facing the shaft-side third contact surface, and the impeller-side third contact surface as the impeller-side contact surface capable of contacting the shaft-side third contact surface ( 961),
2. The fuel pump according to claim 1 , wherein the deformation-permissible space is formed in an odd number, and is deformed when the shaft-side third contact surface and the impeller-side third contact surface come into contact with each other. A plurality of said deformable space, fuel pump according to any one of claims 1 to 3, characterized in that provided at equal intervals on a concentric circle centered on the point on the central axis of the impeller. The impeller is
A plurality of inclined surfaces ( 84, 94) provided at an end portion on the radially outer side of the impeller and protruding by pressurizing fuel using rotation of the impeller;
A fitting hole forming surface ( 863, 864, 963) connecting the both ends of the impeller side contact surface is formed so that the cross-sectional shape is an arc shape having a center on the center axis of the fitting hole;
The deformation-allowed space has a center on the center axis of the fitting hole and a virtual circle ( VL84, VL94) that has a center on the center axis of the fitting hole and connects a radially inner portion of the inclined surface. And is located radially inward from an intermediate virtual circle ( VL88, VL98) that is equidistant from a virtual circle ( VL86, VL96) that connects the radially outer portions of the fitting hole forming surface. The fuel pump according to any one of claims 1 to 5 .

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