JP6485182B2 - Fuel pump - Google Patents

Description

  The present invention relates to a fuel pump that sequentially sucks fuel into each pump chamber and then discharges the fuel.

  2. Description of the Related Art Conventionally, fuel pumps are known in which fuel is sequentially drawn into each pump chamber and then discharged. The fuel pump disclosed in Patent Document 1 includes an outer gear having a plurality of inner teeth, an inner gear having a plurality of outer teeth, the outer gear being eccentrically fitted in an eccentric direction, and a pump housing that rotatably accommodates both gears. And an electric motor having a rotating shaft for rotational driving. The outer gear and the inner gear rotate to the rotational advance side while expanding or reducing the volume of the pump chamber formed between the two gears, thereby sequentially sucking fuel into each pump chamber and then discharging it.

  And the coupling has connected the rotating shaft and the inner gear. In this coupling, the protruding portion that protrudes in the radial direction is engaged with the inner wall groove of the inner gear.

JP-A-6-123288

  However, in the coupling of the fuel pump of Patent Document 1, it is the flat surface of the protruding portion that faces the flat portion of the inner wall groove of the inner gear in the circumferential direction. In such a configuration, when the contact position or contact angle of the coupling with the inner gear changes due to, for example, displacement of the rotation shaft, a component force other than the circumferential direction is generated in the driving force transmitted from the coupling to the inner gear, or the diameter When the edge of the protruding portion in the direction hits the flat portion of the inner wall groove, the load may concentrate on the edge portion. There is concern about a decrease in pump efficiency due to these factors.

  The present invention has been made in view of the problems described above, and an object thereof is to provide a fuel pump having high pump efficiency.

The present invention includes an outer gear (130) having a plurality of internal teeth (132a),
An inner gear (120) having a plurality of external teeth (124a) and being eccentrically fitted with the outer gear (De);
A pump housing (110) for rotatably housing an outer gear and an inner gear;
An electric motor (104) having a rotating shaft (104a) for rotational driving;
A joint member (160) that rotates the inner gear in the circumferential direction by relaying the rotation shaft with the inner gear;
The outer gear and the inner gear rotate while expanding and contracting the volume of a plurality of pump chambers (140) formed between the two gears, so that fuel is sequentially sucked into each pump chamber and then discharged.
The inner gear has an insertion hole (127) that is recessed along the axial direction,
The joint member
A main body (162) fitted to the rotation shaft;
A leg portion (164) that extends along the axial direction from the main body portion and is inserted with a gap in the insertion hole;
The insertion hole has a flat portion (127a) along the radial direction on the inner wall on the drive rotation side with respect to the foot portion,
The foot portion has a top portion (165) that faces the flat portion in the circumferential direction and curves in a convex shape when a cross section perpendicular to the axial direction is viewed from the axial direction .

According to such an invention, when the rotating shaft of the electric motor is driven to rotate, the joint member having the main body portion fitted to the rotating shaft rotates together with the rotating shaft. And since the foot | leg part extended along an axial direction from a main-body part is inserted in the insertion hole of the inner gear with the clearance gap, the inner gear rotates to the circumferential direction by relay of a joint member. Here, in the insertion hole, the inner wall on the drive rotation side with respect to the foot portion has a flat portion along the radial direction. In one leg portion, a top portion that curves in a convex shape in a state where a cross section perpendicular to the axial direction is viewed from the axial direction is opposed to the flat portion in the circumferential direction. According to this, even when the contact position or the contact angle of the foot with respect to the insertion hole is changed, when the top portion contacts the flat portion, the driving force transmitted from the joint member to the inner gear has a radial component force. Since generation | occurrence | production is suppressed and it can suppress that a load concentrates on the specific location of a joint member, an inner gear can be efficiently rotated over a long period of time. As described above, a fuel pump with high pump efficiency can be provided.

  In addition, the code | symbol in a parenthesis is not what was intended to limit the content of invention, only to illustrate the structure which respond | corresponds in embodiment mentioned later in order to make an understanding of description content easy.

It is a partial section front view showing a fuel pump in one embodiment. It is the cross-sectional top view which planarly viewed the II-II line cross section of FIG. It is the cross-sectional top view which planarly viewed the III-III line cross section of FIG. It is the cross-sectional top view which planarly viewed the IV-IV line cross section of FIG. It is a top view of the inner gear in one Embodiment. It is the elements on larger scale which show the relationship between an insertion hole and a leg part. It is a top view of the joint member in one embodiment. It is the VIII-VIII sectional view taken on the line of FIG. FIG. 7 is a diagram corresponding to FIG. 6 in an example of Modification 1; FIG. 7 is a diagram corresponding to FIG. 6 in another example of the first modification.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a fuel pump 101 according to an embodiment of the present invention is a positive displacement trochoid pump mounted on a vehicle. The fuel pump 101 includes a side cover 105 that projects outward from an end opposite to the pump body 103 with the pump body 103 and the electric motor 104 housed in the cylindrical pump body 102 in the axial direction. . Here, the side cover 105 includes an electrical connector 105a for energizing the electric motor 104 and a discharge port 105b for discharging fuel. In such a fuel pump 101, the rotating shaft 104a of the electric motor 104 is rotationally driven by energization from an external circuit via the electrical connector 105a. As a result, the fuel sucked and pressurized by the rotation of the outer gear 130 and the inner gear 120 of the pump body 103 using the driving force of the rotating shaft 104a of the electric motor 104 is discharged from the discharge port 105b. . In addition, about the fuel pump 101, the light oil whose viscosity is higher than gasoline is discharged as a fuel.

  In the present embodiment, as the electric motor 104, an inner rotor type brushless motor in which the magnet 104b is formed in 4 poles and the coil 104c is formed in 6 slots is employed. For example, when the vehicle IG-ON or the accelerator pedal of the vehicle is depressed, the electric motor 104 performs positioning control to rotate the rotating shaft 104a to the drive rotation side or the drive rotation reverse side. Thereafter, the electric motor 104 performs drive control to rotate the rotary shaft 104a toward the drive rotation side from the position positioned by the positioning control.

  Here, the drive rotation side indicates the side that is the positive direction of the rotation direction Rig in the circumferential direction of the inner gear 120. Further, the reverse side of the drive rotation indicates the side that is the negative direction of the rotation direction Rig in the circumferential direction of the inner gear 120.

  Hereinafter, the pump body 103 will be described in detail. The pump main body 103 includes a pump housing 110, an inner gear 120, an outer gear 130, and a joint member 160. Here, the pump housing 110 is formed by overlapping a pump cover 112 and a pump casing 116.

  The pump cover 112 is formed in a disk shape from metal. The pump cover 112 projects outward from an end of the pump body 102 opposite to the side cover 105 with the electric motor 104 sandwiched in the axial direction.

  The pump cover 112 shown in FIGS. 1 and 2 forms a cylindrical hole-like suction port 112a and an arc-shaped groove-like suction passage 113 in order to suck fuel from the outside. The suction port 112 a passes through a specific opening portion Ss that is eccentric from the inner center line Cig of the inner gear 120 in the pump cover 112 along the axial direction of the cover 112. The suction passage 113 is open to the pump casing 116 side of the pump cover 112. As shown in FIG. 2, the inner peripheral portion 113 a of the suction passage 113 extends along the rotational direction Rig of the inner gear 120 (see also FIG. 4) to a length of less than half a circumference. An outer peripheral portion 113b of the suction passage 113 extends along the rotational direction Rog of the outer gear 130 to a length of less than a half circumference.

  Here, the suction passage 113 is widened from the start end portion 113c toward the end portion 113d in the rotational directions Rig and Rog. The suction passage 113 communicates with the suction port 112a by opening the suction port 112a at the opening portion Ss of the groove bottom 113e. In particular, as shown in FIG. 2, the width of the suction passage 113 is set to be smaller than the width of the suction port 112a in the entire opening portion Ss where the suction port 112a opens.

  Further, the pump cover 112 forms a recessed hole-shaped arrangement space 158 in which the main body portion 162 of the joint member 160 is rotatably arranged at a position facing the inner gear 120 on the inner center line Cig.

  The pump casing 116 shown in FIGS. 1, 3 and 4 is made of a metal and has a bottomed cylindrical shape. The opening 116 a in the pump casing 116 is covered with the pump cover 112, so that the entire circumference is sealed. As shown particularly in FIGS. 1 and 4, the inner peripheral portion 116 b of the pump casing 116 is formed in a cylindrical hole shape that is eccentric from the inner center line Cig of the inner gear 120.

  The pump casing 116 forms an arc-hole-like discharge passage 117 in order to discharge fuel from the discharge port 105 b through the fuel passage 106 between the pump body 102 and the electric motor 104. The discharge passage 117 penetrates the concave bottom portion 116c of the pump casing 116 along the axial direction. In particular, as shown in FIG. 3, the inner peripheral portion 117 a of the discharge passage 117 extends along the rotational direction Rig of the inner gear 120 to a length of less than half a circumference. The outer peripheral portion 117b of the discharge passage 117 extends along the rotational direction Rog of the outer gear 130 to a length less than a half circumference. Here, the discharge passage 117 is reduced in width toward the end portion 117d from the start end portion 117c.

  The pump casing 116 has reinforcing ribs 116 d in the discharge passage 117. The reinforcing rib 116d is formed integrally with the pump casing 116, and is a rib that reinforces the pump casing 116 by straddling the discharge passage 117 in a direction intersecting the rotational direction Rig of the inner gear 120.

  In the concave bottom portion 116c of the pump casing 116, a portion facing the suction passage 113 with a pump chamber 140 (described in detail later) between the two gears 120 and 130 is sandwiched, as shown in FIG. Corresponding to the shape projected in the direction, an arc groove-like suction groove 118 is formed. Thus, in the pump casing 116, the discharge passage 117 is provided with the suction groove 118 and its outline approximately symmetrical with respect to the line. On the other hand, as shown in FIG. 2 in particular, a portion of the pump cover 112 facing the discharge passage 117 across the pump chamber 140 has an arc groove shape corresponding to the shape projected in the axial direction of the passage 117. A discharge groove 114 is formed. Thus, in the pump cover 112, the suction passage 113 is provided with the discharge groove 114 and its outline approximately symmetrical with respect to the line.

  As shown in FIG. 1, a radial bearing 150 is fitted and fixed on the inner center line Cig of the concave bottom portion 116 c of the pump casing 116 in order to radially support the rotating shaft 104 a of the electric motor 104. . On the other hand, a thrust bearing 152 is fitted and fixed on the inner center line Cig of the pump cover 112 in order to support the rotating shaft 104a in the axial direction.

  As shown in FIGS. 1 and 4, the recessed bottom portion 116 c and the inner peripheral portion 116 b of the pump casing 116 define an accommodation space 156 for accommodating the inner gear 120 and the outer gear 130 in cooperation with the pump cover 112. The inner gear 120 and the outer gear 130 are so-called trochoidal gears in which their teeth are trochoidal curved.

  The inner gear 120 shown in FIGS. 1 and 4 to 6 is arranged eccentrically in the accommodation space 156 by sharing the inner center line Cig with the rotation shaft 104a. The inner peripheral portion 122 of the inner gear 120 is radially supported by a radial bearing 150, and the sliding surfaces 125 on both axial sides are supported by the concave bottom portion 116c of the pump casing 116 and the pump cover 112.

  Further, the inner gear 120 has an insertion hole 127 that is recessed along the axial direction at a location facing the arrangement space 158. In the present embodiment, a plurality of insertion holes 127 (five in this embodiment) are provided at equal intervals in the circumferential direction along the rotation direction Rig, and each insertion hole 127 penetrates to the concave bottom portion 116c side. By inserting the corresponding foot portions 164 of the joint member 160 into the insertion holes 127, the driving force of the rotating shaft 104a is transmitted to the inner gear 120 via the joint member 160. Thus, the inner gear 120 can rotate in the circumferential direction around the inner center line Cig while sliding the sliding surface 125 on the concave bottom portion 116 c and the pump cover 112 according to the rotation of the rotating shaft 104 a of the electric motor 104. ing.

  The inner gear 120 has a plurality of external teeth 124 a arranged at equal intervals in the circumferential direction along the rotation direction Rig on the outer peripheral portion 124. Each outer tooth 124a can be opposed to each passage 113, 117 and each groove 114, 118 in the axial direction according to the rotation of the inner gear 120, so that sticking to the concave bottom portion 116c and the pump cover 112 is suppressed. ing.

  As shown in FIGS. 5 and 6, each insertion hole 127 of the present embodiment has a flat portion 127a, a reverse flat portion 127b, an outer peripheral bending portion 127c, an inner peripheral bending portion 127d, and four corners on each inner wall. It has sections 128a, 128b, 128c, and 128d. Each flat portion 127 a is formed in a radial flat shape along the radial direction of the inner gear 120 on the inner wall on the drive rotation side with respect to the inserted foot portion 164. Each flat portion 127a faces the opposite side of the drive rotation. Each reverse flat portion 127 b is formed in a radial flat shape along the radial direction of the inner gear 120 on the inner wall on the drive rotation reverse side with respect to the foot portion 164. Each reverse flat portion 127b faces the drive rotation side.

  Each outer curved portion 127c is formed in a curved surface shape that curves along the circumferential direction on the inner wall on the outer circumferential side facing the inserted foot portion 164 in the radial direction. Each inner circumferential curved portion 127d is formed in a curved surface shape that curves along the circumferential direction on the inner circumferential inner wall facing the inserted foot portion in the radial direction.

  In each insertion hole 127, the corner portion 128a shown in an enlarged manner in FIG. 6 is adjacent to the flat portion 127a and the outer peripheral curved portion 127c. In each insertion hole 127, the corner portion 128b is adjacent to the flat portion 127a and the inner circumferential curved portion 127d. In each insertion hole 127, the corner portion 128c is adjacent to the reverse flat portion 127b and the outer peripheral curved portion 127c. In each insertion hole 127, the corner portion 128d is adjacent to the reverse flat portion 127b and the inner circumferential curved portion 127d. Each corner 128a-d is curved in a concave shape in plan view, thereby smoothly connecting the adjacent portions. As shown in FIG. 6, the curvature radius Rc of each corner 128a-d is set smaller than the curvature radii Rp1 and Rp2 of the top 165 and the reverse top 166 (detailed later) of the inserted foot 164. . Here, the plan view in the present embodiment indicates a state in which a plane or a cross section perpendicular to the axial direction is viewed from the axial direction, and in this embodiment, FIGS.

  As shown in FIGS. 1 and 4, the outer gear 130 is arranged coaxially in the accommodation space 156 by being eccentric with respect to the inner center line Cig of the inner gear 120. Thereby, with respect to the outer gear 130, the inner gear 120 is eccentric in the eccentric direction De as one radial direction. The outer peripheral portion 134 of the outer gear 130 is supported in the radial direction by the inner peripheral portion 116 b of the pump casing 116, and is supported in the axial direction by the concave bottom portion 116 c of the pump casing 116 and the pump cover 112. With these bearings, the outer gear 130 is rotatable in a certain rotational direction Rog around the outer center line Cog that is eccentric from the inner center line Cig.

  The outer gear 130 has a plurality of internal teeth 132 a arranged at equal intervals in the rotation direction Rog in the inner peripheral portion 132. Here, the number of inner teeth 132 a in the outer gear 130 is set to be one greater than the number of outer teeth 124 a in the inner gear 120. Each internal tooth 132a can be opposed to each passage 113, 117 and each groove 114, 118 in the axial direction according to the rotation of the outer gear 130, so that sticking to the concave bottom portion 116c and the pump cover 112 is suppressed. ing.

  The inner gear 120 meshes with the outer gear 130 by the relative eccentricity in the eccentric direction De. As a result, a plurality of pump chambers 140 are formed between the gears 120 and 130 in the accommodation space 156. The volume of the pump chamber 140 expands and contracts as the outer gear 130 and the inner gear 120 rotate.

  As the gears 120 and 130 rotate, the volume of the pump chamber 140 increases in the pump chamber 140 that communicates with the suction passage 113 and the suction groove 118. As a result, fuel is sucked into the pump chamber 140 from the suction port 112a through the suction passage 113. At this time, since the suction passage 113 is widened from the start end portion 113c toward the end portion 113d (see also FIG. 2), the amount of fuel sucked through the suction passage 113 is the volume expansion amount of the pump chamber 140. Depending on.

  As the gears 120 and 130 rotate, the volume of the pump chamber 140 is reduced in the pump chamber 140 that communicates with the discharge passage 117 and the discharge groove 114. As a result, simultaneously with the suction function, fuel is discharged from the pump chamber 140 to the fuel passage 106 through the discharge passage 117. At this time, the discharge passage 117 is reduced in width toward the end portion 117d from the start end portion 117c (see also FIG. 3), so that the amount of fuel discharged through the discharge passage 117 is reduced in volume of the pump chamber 140. It depends on the amount.

  As shown in FIGS. 1, 2, 4, 6 to 8, the joint member 160 is formed of a synthetic resin such as polyphenylene sulfide (PPS) resin, for example, and relays the rotating shaft 104 a with the inner gear 120, thereby the inner gear 120. Rotate in the circumferential direction. The joint member 160 has a main body portion 162 and a foot portion 164.

  The main body 162 is disposed in an arrangement space 158 formed in the pump cover 112, and is formed in an annular shape having a fitting hole 162a opened at the center, and the rotating shaft 104a is inserted into the fitting hole 162a. Thus, the rotary shaft 104a is fitted and fixed.

  A plurality of foot portions 164 are provided corresponding to the number of insertion holes 127 of the inner gear 120. Specifically, in order to reduce the influence of torque ripple of the electric motor 104, the number of legs 164 is a number that avoids the number of poles and the number of slots of the electric motor 104, and is provided with five prime numbers in particular. Each of these foot portions 164 is provided as extending along the axial direction from a plurality of locations (five locations in the present embodiment) on the outer peripheral side of the fitting hole 162a that is a fitting location of the main body portion 162. ing. The plurality of legs 164 are arranged at equal intervals in the circumferential direction. Each foot 164 can be elastically deformed by a material having elasticity and a shape extending along the axial direction. When the rotary shaft 104a is rotationally driven, each leg portion 164 is elastically deformed according to the corresponding insertion hole 127, so that a dimensional error in the circumferential direction of each insertion hole 127 and each leg portion 164 that may occur during manufacturing. The foot 164 and the insertion hole 127 come into contact with each other while absorbing the water. As a result, the joint member 160 transmits the driving force of the rotating shaft 104 a to the inner gear 120 through the plurality of legs 164.

  Each such leg 164 is inserted into the corresponding insertion hole 127 with a gap. As shown in FIG. 1 in particular, the tip 164a of each foot 164 extends in the axial direction toward the electric motor 104 from the center of gravity of the inner gear 120 with respect to the insertion hole 127 that penetrates the inner gear 120 in the axial direction. However, it is extended so as not to reach the outside of the insertion hole 127. Further, the tip 164a of each foot 164 has a guide shape for facilitating assembly at the time of manufacture as shown in FIG.

  Each foot portion 164 has a top portion 165 that faces the flat portion 127a in the circumferential direction. The top portion 165 is curved in a convex shape in plan view, and in particular in the present embodiment, is formed in a semi-cylindrical shape having a generatrix along the axial direction.

  Each foot portion 164 has a reverse apex portion 166 that faces the reverse flat portion 127b in the circumferential direction. The reverse apex portion 166 is curved in a convex shape in plan view, and in particular in the present embodiment, is formed in a semi-cylindrical shape having a generatrix along the axial direction.

  Between the top portion 165 and the reverse top portion 166 of each foot 164 provided with the top portion 165 and the reverse top portion 166, the inner gear 120 has a circumference in accordance with the shapes of the outer peripheral curved portion 127 c and the inner peripheral curved portion 127 d of the insertion hole 127. Curved along the direction. Here, in particular, as shown in FIG. 6, the curvature radius Rvo of the outer circumferential curved portion 127c, the curvature radius Rvi of the inner circumferential curved portion 127d, the curvature radius Rf1 of the outer circumferential side of the foot portion 164, and the curvature radius Rf2 of the inner circumferential side are: , And is set according to the distance to the inner center line Cig. Specifically, the curvature radii Rf1 and Rf2 are set to be larger than the curvature radius Rvi and smaller than the curvature radius Rvo. In the present embodiment, the curvature radii Rvo, Rvi, Rf1, and Rf2 are set substantially equal to the distance to the inner center line Cig, so that the center of curvature is on the inner center line Cig.

  Thus, in the positioning control of the electric motor 104, for example, when the rotating shaft 104a rotates on the opposite side of the drive rotation, the top portion 165 separates from the flat portion 127a, while the reverse top portion 166 collides with the reverse flat portion 127b and comes into contact. Meanwhile, the inner gear 120 is rotated in the negative direction of the rotational direction Rig in the circumferential direction. Thereafter, when the drive control of the electric motor 104 is started, the reverse top portion 166 is separated from the reverse flat portion 127b, while the top portion 165 collides with the flat portion 127a, and the inner gear 120 is rotated in the circumferential direction while contacting. Rotate to Rig. The fuel pump 101 of this embodiment repeatedly sucks fuel into each pump chamber 140 and discharges it from each pump chamber 140 during driving while repeatedly withstanding the collision at the time of startup.

(Function and effect)
The operational effects of the present embodiment described above will be described below.

  According to the present embodiment, when the rotary shaft 104a of the electric motor 104 is driven to rotate, the joint member 160 having the main body 162 fitted to the rotary shaft 104a rotates together with the rotary shaft 104a. And since the leg part 164 extended | stretched along the axial direction from the main-body part 162 is inserted in the insertion hole 127 of the inner gear 120 with a clearance gap, the inner gear 120 rotates in the circumferential direction by the relay of the joint member 160. Here, in the insertion hole 127, the inner wall on the drive rotation side with respect to the foot 164 has a flat portion 127a along the radial direction. In the one foot portion 164, a top portion 165 that curves in a convex shape in plan view is opposed to the flat portion 127a in the circumferential direction. According to this, even when the contact position or contact angle of the foot part 164 with respect to the insertion hole 127 changes, the driving force transmitted from the joint member 160 to the inner gear 120 when the top part 165 contacts the flat part 127a. Since generation | occurrence | production of radial component force is suppressed and it can suppress that a load concentrates on the specific location of the joint member 160, the inner gear 120 can be efficiently rotated over a long period of time. As described above, the fuel pump 101 with high pump efficiency can be provided.

  In addition, according to the present embodiment, the insertion hole 127 has the corner portions 128a and 128b that are adjacent to the flat portion 127a and curved concavely in plan view, and the curvature radius Rc at the corner portions 128a and 128b is equal to that at the top portion 165. It is smaller than the curvature radius Rp1. When the radius of curvature Rp1 is set, the flat portion 127a can be set wide in the insertion hole 127. Therefore, even if the contact position or the contact angle of the foot portion 164 with respect to the insertion hole 127 changes, the top portion 165 is fixed to the flat portion. 127a can be reliably brought into contact with.

  In addition, according to the present embodiment, a plurality of insertion holes 127 having a flat portion 127a are provided, and a foot portion 164 having a top portion 165 extends from a plurality of locations on the outer peripheral side of the fitting hole 162a of the main body portion 162. Are provided as a plurality. These foot portions 164 are provided so as to be elastically deformable. According to this, even when the foot portion 164 is elastically deformed to the outer peripheral side due to the centrifugal force generated by driving the rotating shaft 104a, the top portion 165 can be reliably brought into contact with the flat portion 127a.

  Further, according to the present embodiment, the plurality of insertion holes 127 and the plurality of feet 164 are arranged at equal intervals in the circumferential direction. By arranging at equal intervals, it is possible to suppress the fluctuation of the driving force due to the rotation phase of the inner gear 120 and the occurrence of pulsation, so that the pump efficiency can be increased.

  Further, according to the present embodiment, the insertion hole 127 has the reverse flat portion 127b along the radial direction on the inner wall on the drive rotation reverse side with respect to the foot portion 164, and the foot portion 164 includes the reverse flat portion 127b. And a reverse apex portion 166 that is curved in a convex shape in plan view. According to this, even when the rotary shaft 104a rotates to the reverse side of the drive rotation due to, for example, positioning control at the time of starting the electric motor 104, the joint member 160 is in contact with the reverse top portion 166 when contacting the reverse flat portion 127b. The generation of radial component force in the driving force transmitted from the inner gear 120 to the inner gear 120 is suppressed, and the concentration of the load at a specific location of the joint member 160 can be suppressed. Therefore, the inner gear 120 can be efficiently rotated over a long period of time.

  Further, according to the present embodiment, the foot portion 164 is curved along the circumferential direction, and the insertion hole 127 is a curved portion 127c that is curved along the circumferential direction on the inner wall opposed to the foot portion 164 in the radial direction. ~ D. According to such a curve, when the top portion 165 contacts the flat portion 127a and when the reverse top portion 166 contacts the reverse flat portion 127b, the vertical contact with the flat portion 127a and the reverse flat portion 127b is achieved. The top portion 165 and the reverse top portion 166 can be easily brought into contact with each other at an angle or a contact angle close to vertical. Since the curved portions 127c to 127d are curved along the circumferential direction in the same manner as the foot portion 164, the foot portion 164 is difficult to contact the curved portions 127c to 127d.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not construed as being limited to the embodiment, and can be applied to various embodiments without departing from the gist of the present invention. it can.

  Specifically, as the first modification, the top portion 165 or the reverse top portion 166 can employ various shapes as long as it is curved in a convex shape in plan view. For example, as shown in FIG. 9, the radii of curvature Rp1 and Rp2 of the top 165 or the reverse top 166 in plan view may vary depending on the location. Further, the radii of curvature Rp1 and Rp2 of the top portion 165 or the reverse top portion 166 in plan view may be different on the inner peripheral side and the outer peripheral side. As shown in FIG. 10, a planar portion 164 b may be provided adjacent to the top portion 165 or the reverse top portion 166.

  As a second modification, the joint member 160 may be provided with the foot 164 so as to be elastically deformable, for example, with aluminum other than the synthetic resin.

  As a third modification, the plurality of insertion holes 127 and the plurality of legs 164 may be provided at unequal intervals in the circumferential direction.

  As a fourth modification, the radius of curvature Rc of the corner portions 128a to 128d may be equal to or larger than the radius of curvature Rp1 at the top portion 165.

  As a fifth modification, the inner wall facing the foot 164 in the radial direction may be formed in a flat shape.

  As a sixth modified example, the insertion hole 127 may be formed in a bottomed hole shape that does not penetrate to the concave bottom side as long as the insertion hole 127 is recessed along the axial direction.

  As a modified example 7, the fuel pump 101 may suck and discharge gasoline other than light oil or liquid fuel based thereon as fuel.

  DESCRIPTION OF SYMBOLS 101 Fuel pump, 104 Electric motor, 104a Rotating shaft, 110 Pump housing, 120 Inner gear, 124a External tooth, 127 Insertion hole, 127a Flat part, 127b Reverse flat part, 127c Outer peripheral curved part (curved part), 127d Inner peripheral curved part (Curved part), 128a, 128b corner part, 130 outer gear, 132a internal tooth, 140 pump chamber, 160 joint member, 162 main body part, 162a fitting hole (fitting part), 164 foot part, 165 top part, 166 reverse top part , De Eccentric direction, Rc, Rp1 radius of curvature

Claims (6)

An outer gear (130) having a plurality of internal teeth (132a);
An inner gear (120) having a plurality of external teeth (124a) and meshing eccentrically with the outer gear in an eccentric direction (De);
A pump housing (110) for rotatably housing the outer gear and the inner gear;
An electric motor (104) having a rotating shaft (104a) for rotational driving;
A joint member (160) for rotating the inner gear in the circumferential direction by relaying the rotating shaft with the inner gear;
The outer gear and the inner gear rotate while expanding and contracting the volume of a plurality of pump chambers (140) formed between the two gears, so that fuel is sequentially sucked into each pump chamber and then discharged.
The inner gear has an insertion hole (127) that is recessed along the axial direction,
The joint member is
A main body (162) fitted to the rotating shaft;
The extending along the axial direction from the body portion, and a leg portion to be inserted with a gap (164) in the insertion hole,
The insertion hole has a flat portion (127a) along the radial direction on the inner wall on the drive rotation side with respect to the foot portion,
The fuel pump according to claim 1, wherein the foot portion has a top portion (165) that faces the flat portion in the circumferential direction and curves in a convex shape when a cross section perpendicular to the axial direction is viewed from the axial direction . The insertion hole has a corner portion (128a-b) which is adjacent to the flat portion and curves in a concave shape when a cross section perpendicular to the axial direction is viewed from the axial direction ,
The fuel pump according to claim 1, wherein a radius of curvature (Rc) at the corner portion is smaller than a radius of curvature (Rp1) at the top portion. A plurality of the insertion holes having the flat portion are provided,
A plurality of the foot portions having the top portion are provided as extending from a plurality of locations on the outer peripheral side of the fitting portion (162a) of the main body portion,
The fuel pump according to claim 1, wherein each of the feet is provided to be elastically deformable.   The fuel pump according to claim 3, wherein the insertion holes and the foot portions are arranged at equal intervals in the circumferential direction. The insertion hole has an inverted flat portion (127b) along the radial direction on the inner wall on the opposite side of the drive rotation with respect to the foot portion,
The foot, and wherein the opposite faces in the flat portion and the circumferential direction, has a Gyakuitadaki portion of curving Oite convex cross section perpendicular to the axial direction in a state viewed from the axial direction (166) The fuel pump according to any one of claims 1 to 4. The foot is curved along the circumferential direction;
6. The fuel pump according to claim 5, wherein the insertion hole has a curved portion (127 c to 127 d) that is curved along the circumferential direction on an inner wall facing the foot portion in the radial direction. 7. .

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