JP6421712B2 - Volumetric pump - Google Patents

Description

  The present invention relates to an internal gear type positive displacement pump.

Conventionally, a positive displacement pump that pumps up fuel in a fuel tank and pumps it to an internal combustion engine is known.
In the positive displacement pump described in Patent Document 1, a pump cover is provided on one axial side of a pump portion having a motor and an impeller. The pump cover is provided with a cylindrical suction port forming portion in which a suction port communicating with the pump portion is formed. A cylindrical connecting portion of a filter protector that holds a suction filter that collects foreign matters contained in the fuel is attached to the outside of the suction port forming portion by press-fitting.

JP 2014-152726 A

  However, in the positive displacement pump described in Patent Literature 1, the end of the connection portion of the filter protector on the pump cover side is in contact with the outer wall of the pump cover located on the center side of the suction port forming portion. For this reason, if the connection portion of the filter protector swells with fuel, the connection portion may press the outer wall of the pump cover and move in a direction of coming out of the outer wall of the suction port forming portion.

  In addition, since the positive displacement pump described in Patent Document 1 is provided with the suction port forming portion in the pump cover, the structure of the pump cover is complicated. Therefore, there is a concern that the process of forming the pump cover by cutting or casting becomes complicated. This pump cover is difficult to form by forging.

Furthermore, since the pump cover is exposed in the fuel tank in the positive displacement pump described in Patent Document 1, if the operation noise and vibration generated from the motor or impeller are large, they pass through the pump cover and the fuel tank. May be transmitted to the passenger compartment.
The present invention has been made in view of the above-described points, and provides a positive displacement pump capable of securely fixing constituent members and making the constituent members into a simple shape.

The positive displacement pump of the present invention includes a pump body, a pump cover, a filter joint, and a filter protector. The pump body sucks and discharges fuel by a change in volume of a volume chamber formed between the inner rotor and the outer rotor that rotates as the inner rotor rotates. The pump cover is provided on one side of the pump body in the axial direction, and has a suction port that leads in the axial direction to a predetermined range in the circumferential direction in which the volume of the volume chamber gradually expands due to relative rotation between the inner rotor and the outer rotor. The filter joint has a bottom part that abuts a part of the outer wall of the pump cover opposite to the pump body, and a cylindrical part that extends in a cylindrical shape from the outer edge of the bottom part and fits liquid-tightly to the outer wall in the radial direction of the pump cover. A fuel reservoir that communicates with the suction port is formed inside the bottom portion and the cylindrical portion. The filter protector is connected to the filter joint and has a fuel passage that communicates a space formed inside the suction filter that collects foreign matters contained in the fuel and a fuel reservoir formed in the filter joint. The bottom part of the filter joint comes into contact with a convex part provided at a position including the rotation shafts of the inner rotor and the outer rotor on the outer wall of the pump cover opposite to the pump body.

  Thereby, the filter joint with which this positive displacement pump is equipped fits with a pump cover by a cylinder part, and contact | abuts a part of outer wall of a pump cover by a bottom part. Therefore, even if the tube portion of the filter joint is swollen by the fuel, the end portion of the tube portion does not press the outer wall of the pump cover in the axial direction, so that the filter joint is prevented from coming off from the pump cover.

  Furthermore, since the filter joint forms a fuel reservoir inside the cylinder part and the bottom part, it is possible to ensure a relatively large volume. Therefore, it is not necessary to change the shape of the pump cover and the filter joint greatly according to the suction negative pressure due to the performance of the pump body or the flow rate characteristics, and the volume pump is to share most of those shapes. Is possible. Further, unlike the positive displacement pump described in Patent Document 1, this positive displacement pump does not have a suction port forming portion in the pump cover. Therefore, this positive displacement pump can make a pump cover and a filter joint into a simple shape.

It is sectional drawing of the positive displacement pump by 1st Embodiment of this invention. It is sectional drawing of the II-II line of FIG. It is an enlarged view of the III part of FIG. It is sectional drawing of the IV-IV line of FIG. It is a fragmentary sectional view of the positive displacement pump by 2nd Embodiment of this invention. It is a fragmentary sectional view of the positive displacement pump by a 3rd embodiment of the present invention. It is a fragmentary sectional view of the positive displacement pump of a comparative example. It is the bottom view which showed only the pump cover in the VIII direction of FIG.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments and comparative examples, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
A first embodiment of the present invention is shown in FIGS. The positive displacement pump 1 of the first embodiment is provided, for example, in a fuel tank of a vehicle, and pumps up fuel in the fuel tank and pumps it to an internal combustion engine.
The positive displacement pump 1 includes a pump body 10, a pump cover 30, a filter joint 40, a filter protector 60, and the like.
As shown in FIG. 1, the pump body 10 includes a motor unit 11, an inner rotor 12, an outer rotor 13, a rotor case 14, and the like. The motor unit 11 includes a stator 15, a rotor 16, a shaft 17, and the like. A coil 18 is wound around a slot formed in the stator 15 via an insulator 151. The rotor 16 is rotatably provided inside the stator 15 in the radial direction. The rotor 16 has N poles and S poles alternately arranged in the circumferential direction. The shaft 17 provided at the rotation center of the rotor 16 is rotatably supported on the resin body 20 on one side in the axial direction by the first bearing 19 and can be rotated on the rotor case 14 and the like on the other side by the second bearing 21. While being supported, the tip is placed on the turntable 22. When the coil 18 is energized from the terminal 24 of the connector 23 formed on the resin body 20, the rotor 16 and the shaft 17 are rotated by the rotating magnetic field formed inside the stator 15. A torque transmission member 25 is fixed to the end of the shaft 17 on the turntable 22 side.

As shown in FIGS. 1 and 2, the inner rotor 12 is rotatably provided on the outside of the shaft 17 via a second bearing 21. The inner rotor 12 rotates together with the shaft 17 by torque transmission from the torque transmission member 25 fixed to the shaft 17. An external gear 121 is provided on the radially outer side of the inner rotor 12.
An outer rotor 13 is provided on the radially outer side of the inner rotor 12. The outer rotor 13 is rotatably accommodated inside a rotor case 14 formed in a bottomed cylindrical shape. In FIG. 2, the rotation directions of the inner rotor 12 and the outer rotor 13 are indicated by arrows R.

An internal gear 131 that meshes with one tooth of the external gear 121 is provided on the radially inner side of the outer rotor 13. The center O2 of the internal gear 131 is eccentric with respect to the center O1 of the external gear 121. Further, the number of teeth of the internal gear 131 is one more than the number of teeth of the external gear 121. By the meshing of the internal gear 131 and the external gear 121, the torque of the inner rotor 12 is transmitted to the outer rotor 13. Thereby, the outer rotor 13 is also rotated together with the inner rotor 12. In the present embodiment, the rotation axes of the inner rotor 12 and the outer rotor 13 are coaxial with the center O1 of the external gear 121. For this reason, reference numerals O1 are also given to the rotating shafts of the inner rotor 12 and the outer rotor 13.
When the inner rotor 12 and the outer rotor 13 rotate, the plurality of volume chambers 26 formed between the inner rotor 12 and the outer rotor 13 each shift the range indicated by the arrow α in FIG. The volume gradually expands according to this. Further, the volumes of the plurality of volume chambers 26 are gradually reduced as the range indicated by arrow β in FIG. 2 is shifted from B to A.

  As shown in FIG. 3, the rotor case 14 has a discharge port 27 that communicates with the volume chamber 26. The discharge port 27 is provided in a predetermined circumferential range within the range indicated by the arrow β in FIG. The discharge port 27 is formed in a substantially arc shape and communicates in the axial direction. On the other hand, in the pump cover 30, a discharge pressure adjusting groove 28 is provided at a position located on the opposite side of the discharge port 27 across the inner rotor 12 and the outer rotor 13. The pressure of the fuel entering the discharge pressure adjusting groove 28 prevents the inner rotor 12 and the outer rotor 13 from being inclined by the fuel pressure discharged from the volume chamber 26 to the discharge port 27.

The pump cover 30 is formed of, for example, metal or the like, and is provided on the side opposite to the axial motor portion 11 of the inner rotor 12, the outer rotor 13, and the rotor case 14 of the pump body 10. The pump body 10 and the pump cover 30 are fixed by a cylindrical pump housing 29 that surrounds the radially outer side thereof.
The pump cover 30 includes a shaft housing hole 31, a suction port 32, an outer edge portion 33, a fitting portion 34, a step surface 35, and a convex portion 36.
The shaft accommodation hole 31 provided on the pump body 10 side of the pump cover 30 accommodates the shaft 17, the torque transmission member 25 provided at the end thereof, and the turntable 22.

  As shown in FIGS. 2 to 4, the pump cover 30 has a suction port 32 communicating with the volume chamber 26. The suction port 32 is provided in a predetermined circumferential range within the range indicated by the arrow α in FIG. The suction port 32 is formed in a substantially arc shape and communicates in the axial direction. On the other hand, in the rotor case 14, a suction pressure adjusting groove 37 is provided at a position on the opposite side of the suction port 32 with the inner rotor 12 and the outer rotor 13 interposed therebetween. The pressure of the fuel entering the suction pressure adjusting groove 37 prevents the inner rotor 12 and the outer rotor 13 from being inclined by the suction negative pressure from the suction port 32 to the volume chamber 26.

The outer diameter of the outer edge portion 33 of the pump cover 30 is the same as the outer diameter of the rotor case 14. The end of the pump housing 29 is fixed to the end of the outer edge 33 opposite to the rotor case 14 by caulking.
The fitting portion 34 is provided on the opposite side of the outer edge portion 33 from the rotor case 14. The outer diameter of the fitting part 34 is formed smaller than the outer diameter of the outer edge part 33. The tube portion 44 of the first filter joint 41 is fitted into the fitting portion 34 by press fitting. A step surface 35 connects the outer edge portion 33 and the fitting portion 34.
On the outer wall of the pump cover 30 on the side opposite to the pump main body 10, a convex portion 36 that protrudes on the side opposite to the pump main body 10 is provided. The convex portion 36 is provided on the opposite side of the shaft accommodation hole 31 at a position including the rotation axis O <b> 1 of the inner rotor 12 and the outer rotor 13. In addition, this convex part 36 is corresponded to an example of "a part of outer wall on the opposite side to the said pump main body of the said pump cover" as described in a claim.

The filter joint 40 includes a first filter joint 41 and a second filter joint 42. Note that the first filter joint 41 and the second filter joint 42 may be integrally formed as in a second embodiment described later.
The 1st filter joint 41 is formed, for example from resin etc., and is provided in the opposite side to the pump main body 10 of the pump cover 30. FIG. The first filter joint 41 has a disk-like bottom 43, a cylinder 44 extending in a cylindrical shape from the outer edge of the bottom 43 toward the pump cover 30, and a cylinder extending from the bottom 43 to the opposite side of the pump cover 30. It has a connection part 45. The bottom portion 43 abuts on the convex portion 36 of the pump cover 30. As a result, the axial positions of the first filter joint 41 and the pump cover 30 are determined.

  The cylindrical portion 44 is provided such that the central axis thereof is coaxial with the rotation axis O1 of the inner rotor 12 and the outer rotor 13. The cylinder part 44 surrounds the radial outer wall of the pump cover 30 in a cylindrical shape. The cylinder portion 44 is press-fitted into the fitting portion 34 of the pump cover 30 and is fitted into the fitting portion 34 in a liquid-tight manner. As a result, a fuel reservoir 46 is formed inside the bottom portion 43 and the cylindrical portion 44. The fuel reservoir 46 communicates with the suction port 32.

  As shown in FIG. 3, in the state where the convex portion 36 and the bottom portion 43 of the pump cover 30 are in contact with each other, the end portion of the cylindrical portion 44 opposite to the bottom portion 43 in the axial direction and the step surface 35 of the pump cover 30 A predetermined gap S is formed between them. In other words, the opposite side of the cylindrical portion 44 from the bottom portion 43 in the axial direction is opened in the axial direction without coming into contact with other members including the stepped surface 35 on the entire circumference. For this reason, even if the cylindrical portion 44 is swollen by the fuel, the gap S formed between the cylindrical portion 44 and the stepped surface 35 becomes an allowance for the cylindrical portion 44, so that the cylindrical portion 44 contacts the stepped surface 35. It is prevented from moving in the direction of coming out of the pump cover 30 in contact.

The first filter joint 41 protrudes from the bottom 43 to the opposite side of the pump cover 30 at a position away from the connecting portion 45, and the connecting portion 45 extending in a cylindrical shape from the bottom 43 to the opposite side of the pump cover 30. A protrusion 47 is further provided. A fuel hole 48 communicating with the fuel reservoir 46 is formed inside the connecting portion 45.
The second filter joint 42 is made of, for example, resin, and is provided on the opposite side of the first filter joint 41 from the pump cover 30. The second filter joint 42 has a fitting tube 49 that fits radially outside the connecting portion 45 of the first filter joint 41 and a positioning hole 50 into which the projection 47 of the first filter joint 41 is inserted.

  The filter protector 60 is connected to a suction filter 61 that collects foreign matters contained in the fuel. The filter protector 60 includes, for example, a connecting portion 62 that is formed from a resin or the like and is fitted inside the fitting tube 49 of the second filter joint 42 in the radial direction. A fuel passage 63 is formed inside the connecting portion 62. The fuel passage 63 communicates a space 64 formed inside the suction filter 61 and a fuel hole 48 formed inside the connection portion 45 of the first filter joint 41. As described above, the fuel hole 48 and the fuel reservoir 46 of the first filter joint 41 communicate with each other.

The fuel sucked into the space 64 inside the suction filter 61 passes through the fuel passage 63 of the filter protector 60, the fuel hole 48 of the first filter joint 41 and the fuel reservoir 46, and is pumped from the suction port 32 of the pump cover 30. Inhaled into the volume chamber 26 of the main body 10. When the volume chamber 26 moves in the range indicated by the arrow α in FIG. 2 due to the rotation of the inner rotor 12 and the outer rotor 13, the volume chamber 26 sucks in fuel as the volume increases.
On the other hand, when the volume chamber 26 moves from the range indicated by the arrow α in FIG. 2 to the range indicated by the arrow β, as the volume of the volume chamber 26 decreases, the discharge port 27 of the rotor case 14 moves to the motor unit 11 side. Fuel is discharged. As shown in FIG. 1, the fuel passes between the rotor 16 and the stator 15, between the stator 15 and the pump housing 29, passes through the discharge passage 200 formed in the resin body 20, and passes through the discharge pump 200. Is discharged to the outside.

Here, the positive displacement pump 100 according to the comparative example will be described with reference to FIGS.
In the positive displacement pump 100 of the comparative example, the pump cover 300 has a cylindrical portion 301 and a protruding portion 302 on the opposite side of the suction port 32 from the pump body 10. The cylindrical portion 301 is provided at a position shifted from the rotation axis O1 of the inner rotor 12 and the outer rotor 13 in the radially outward direction. A passage 303 formed inside the cylindrical portion 301 communicates with a part of the suction port 32 formed in a substantially arc shape when viewed from the axial direction.
The filter joint 400 includes a connecting tube portion 401 that fits outside the cylindrical portion 301 of the pump cover 300 and a positioning hole 402 into which the protruding portion 302 of the pump cover 300 is inserted. An end portion of the connecting tube portion 401 on the pump cover 300 side is in contact with an outer wall 304 of the pump cover 300 located on the center side of the cylindrical portion 301. Therefore, when the connecting tube portion 401 of the filter joint 400 is swollen by the fuel, the connecting tube portion 401 may press the outer wall 304 of the pump cover 300 and move in a direction of coming out of the cylindrical portion 301.

Moreover, since the volumetric pump 100 of the comparative example is provided with the cylindrical portion 301 in the pump cover 300, the configuration thereof is complicated. Therefore, it is considered that the process of forming the pump cover 300 by cutting or casting becomes complicated. It is difficult to form the pump cover 300 by forging.
Further, in the volumetric pump 100 of the comparative example, it is necessary to change the inner diameter of the cylindrical portion 301 of the pump cover 300 according to the suction negative pressure due to the performance of the pump main body 10 or the flow rate characteristic, thereby preventing vapor lock. Therefore, the type of the pump cover 300 of the comparative example increases according to the performance or flow rate characteristics of the pump body 10.

Further, in the positive displacement pump 100 of the comparative example, it is considered that the connection portion between the cylindrical portion 301 of the pump cover 300 and the suction port 32 becomes the fluid resistance of the fuel flowing therethrough. Therefore, the positive displacement pump 100 of the comparative example may increase the fuel intake pulsation.
Furthermore, since the pump cover 300 is exposed in the fuel tank of the positive displacement pump 100 of the comparative example, when the operation noise and vibration generated from the inner rotor 12 and the outer rotor 13 are large, they are the pump cover 300 and the fuel tank. There is a risk of being transmitted to the passenger compartment via.

  Further, in the volumetric pump 100 of the comparative example, the cylindrical portion 301 of the pump cover 300 and the connecting cylinder portion 401 of the filter joint 400 are connected at a position away from the rotation axis O1 of the inner rotor 12 and the outer rotor 13. Therefore, since the distance between the rotation axis O1 of the inner rotor 12 and the outer rotor 13 and the center of gravity of the filter joint 400 is increased, there is a concern that the vibration of the pump body 10 caused by the rotation of the inner rotor 12 and the outer rotor 13 may increase. The

In contrast to the volume pump 100 of the comparative example described above, the volume pump 1 of the first embodiment has the following operational effects.
(1) In the first embodiment, since the first filter joint 41 forms the fuel reservoir 46 inside the cylindrical portion 44 and the bottom portion 43, it is possible to ensure a relatively large volume. Therefore, the positive displacement pump 1 does not need to greatly change the shapes of the pump cover 30 and the first filter joint 41 in accordance with the suction negative pressure due to the performance of the pump body 10 or the flow rate characteristics, and most of those shapes are not required. It can be common. Therefore, the positive displacement pump 1 can simplify the shapes of the pump cover 30 and the first filter joint 41. As a result, the pump cover 30 can be easily formed by cutting or casting, and can also be formed by forging. Therefore, the manufacturing cost can be reduced, the processing accuracy can be improved, and the metal density can be increased in forging to increase the strength.

(2) In the first embodiment, the filter joint 40 is fitted to the pump cover 30 by the cylindrical portion 44, and abuts against a part of the outer wall of the pump cover 30 by the bottom portion 43. Therefore, even if the cylinder part 44 of the filter joint 40 is swollen by the fuel, the filter joint 40 is prevented from coming off the pump cover 30 without the cylinder part 44 pressing the outer wall of the pump cover 30.

(3) Furthermore, in the first embodiment, a portion that becomes a fluid resistance is not formed between the fuel reservoir 46 of the first filter joint 41 and the suction port 32 of the pump cover 30, thereby reducing fuel suction pulsation. Is possible.

(4) In the first embodiment, the first filter joint 41 and the fuel reservoir 46 covering the opposite side of the pump body 30 of the pump cover 30 cause operation noise and vibration accompanying rotation of the inner rotor 12 and the outer rotor 13. It is possible to reduce the amount transmitted to the fuel pump.

(5) In the first embodiment, the side opposite to the axial bottom 43 of the cylindrical portion 44 of the first filter joint 41 is opened in the axial direction without contacting the step surface 35 on the entire circumference.
As a result, even when the first filter joint 41 is swollen by the fuel, there is room for extension in the axial direction of the cylindrical portion 44, so that the cylindrical portion 44 is prevented from moving in the direction in which the cylindrical portion 44 comes off from the radial outer wall of the pump cover 30. Can be removed. Therefore, the positive displacement pump 1 can securely fix the pump cover 30 and the first filter joint 41.
When the pump cover 30 and the first filter joint 41 are assembled by press-fitting the cylindrical portion 44 into the radial outer wall of the pump cover 30, the end of the cylindrical portion 44 opposite to the axial bottom portion 43 is used. The reaction force of press-fitting is not applied from the stepped surface 35 or the like. Therefore, since the deformation | transformation etc. of the cylinder part 44 are prevented, the positive displacement pump 1 can fit the pump cover 30 and the cylinder part 44 liquid-tightly.

(6) In 1st Embodiment, the cylinder part 44 which the 1st filter joint 41 has has enclosed the outer wall of the radial direction of the pump cover 30 in the cylinder shape.
Thereby, the volume pump 1 can reduce the amount of operating noise and vibration transmitted to the fuel tank and the like due to the rotation of the inner rotor 12 and the outer rotor 13 by the cylindrical portion 44 of the first filter joint 41. .
The positive displacement pump 1 can also absorb vibrations and operating noises by the bottom 43 and the fuel reservoir 46 of the first filter joint 41.

(7) In the first embodiment, the rotation axis O1 of the inner rotor 12 and the outer rotor 13 and the center of the cylindrical portion 44 of the first filter joint 41 are coaxial.
Thereby, the distance between the rotation axis O1 of the inner rotor 12 and the outer rotor 13 and the center of gravity of the first filter joint 41 is reduced. Therefore, the positive displacement pump 1 can reduce the vibration of the pump body 10 caused by the rotation of the inner rotor 12 and the outer rotor 13. Therefore, the positive displacement pump 1 can reduce vibration transmitted from the pump body 10 to the vehicle interior via the fuel tank.

(8) In the first embodiment, the bottom portion 43 of the first filter joint 41 abuts on the convex portion 36 provided on the outer wall of the pump cover 30. The convex portion 36 is provided at a position including the rotation axis O1 of the inner rotor 12 and the outer rotor 13.
Thereby, rotation of the inner rotor 12 and the outer rotor 13 is stabilized. Therefore, the positive displacement pump 1 can reduce vibration caused by the rotation of the inner rotor 12 and the outer rotor 13.
Further, since the position where the first filter joint 41 abuts on the convex portion 36 and the position where the tube portion 44 is fitted to the pump cover 30 are separated from each other, even when the bottom portion 43 swells, It is possible to prevent the cylindrical portion 44 from moving in the direction in which the cylindrical portion 44 comes off from the radially outer wall.

(9) In the first embodiment, a predetermined gap S is formed between the end of the cylindrical portion 44 of the first filter joint 41 opposite to the axial bottom 43 and the step surface 35 of the pump cover 30. Has been.
As a result, when the first filter joint 41 is swollen by the fuel, the predetermined gap S becomes an extension of the cylindrical portion 44, so that the cylindrical portion 44 moves in the direction in which the cylindrical portion 44 comes out from the radial outer wall of the pump cover 30. Is prevented. Therefore, the positive displacement pump 1 can securely fix the pump cover 30 and the first filter joint 41.

(Second and third embodiments)
A second embodiment of the present invention is shown in FIG. The filter joint 51 provided in the positive displacement pump 2 of the second embodiment is one in which the first filter joint 41 and the second filter joint 42 described in the first embodiment are integrally formed.
A third embodiment of the present invention is shown in FIG. The filter joint 52 provided in the positive displacement pump 3 of the third embodiment is formed by integrating the first filter joint 41, the second filter joint 42, and the filter protector 60 described in the first embodiment.
The volumetric pumps 2 and 3 of the second and third embodiments can also have the same effects as the volumetric pump 1 of the first embodiment. Further, in the second and third embodiments, it is possible to reduce the size of the axial pumps 2 and 3 in the axial direction as compared with the first embodiment.

(Other embodiments)
(1) In the above-described embodiment, the suction port 32 and the discharge port 27 are formed in an arc shape. On the other hand, in other embodiments, the shape or size of the suction port 32 and the discharge port 27 can be arbitrarily determined according to the performance or flow rate characteristics of the pump body 10.

(2) In the embodiment described above, the convex portion 36 is provided on the outer wall of the pump cover 30 opposite to the pump body 10. On the other hand, in other embodiments, a convex portion may be provided on the pump cover 30 side of the bottom 43 of the first filter joint 41.
Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention.

1, 2, 3 ... Volumetric pump 10 ... Pump body 30 ... Pump cover 32 ... Suction port 40, 51, 52 ... Filter joint 41 ... First filter joint (filter joint)
42 ... Second filter joint (filter joint)
43 ... Bottom 44 ... Tube 46 ... Fuel reservoir

Claims (5)

A pump body (10) that sucks and discharges fuel by a volume change of a volume chamber (26) formed between the inner rotor (12) and an outer rotor (13) that rotates with the rotation of the inner rotor;
A suction port (32) provided in one axial direction of the pump body and communicating in the axial direction with a predetermined range in the circumferential direction in which the volume of the volume chamber gradually expands by relative rotation between the inner rotor and the outer rotor; A pump cover (30);
A bottom portion (43) that contacts a part of the outer wall of the pump cover opposite to the pump main body, and extends in a cylindrical shape from the outer edge of the bottom portion, and is fluid-tightly fitted to the radial outer wall of the pump cover. A filter joint (40) having a cylinder part (44), and forming a fuel reservoir (46) communicating with the suction port inside the bottom part and the cylinder part;
A fuel passage (63) for communicating a space (64) formed inside a suction filter (61) for collecting foreign matters contained in fuel and the fuel reservoir formed in the filter joint; A filter protector (60) connected to the joint;
With
The bottom portion of the filter joint is in contact with a convex portion (36) provided at a position including the rotation shafts of the inner rotor and the outer rotor on the outer wall of the pump cover opposite to the pump body. Oh Ru capacity product pump. A pump body (10) that sucks and discharges fuel by a volume change of a volume chamber (26) formed between the inner rotor (12) and an outer rotor (13) that rotates with the rotation of the inner rotor;
A suction port (32) provided in one axial direction of the pump body and communicating in the axial direction with a predetermined range in the circumferential direction in which the volume of the volume chamber gradually expands by relative rotation between the inner rotor and the outer rotor; A pump cover (30);
A bottom portion (43) that contacts a part of the outer wall of the pump cover opposite to the pump main body, and extends in a cylindrical shape from the outer edge of the bottom portion, and is fluid-tightly fitted to the radial outer wall of the pump cover. A filter joint (40) having a cylinder part (44), and forming a fuel reservoir (46) communicating with the suction port inside the bottom part and the cylinder part;
A fuel passage (63) for communicating a space (64) formed inside a suction filter (61) for collecting foreign matters contained in fuel and the fuel reservoir formed in the filter joint; A filter protector (60) connected to the joint;
A pump housing (29) surrounding the radially outer side of the pump body ;
With
The pump cover includes an outer edge portion (33) to which the pump housing is fixed, a fitting portion (34) provided radially inward from the outer edge portion and into which the tube portion of the filter joint is fitted, and the outer edge A step surface (35) connecting the portion and the fitting portion,
Description product pump that are formed a predetermined gap (S) is between the stepped surface of the pump cover and an end portion opposite to the bottom portion in the axial direction of the cylindrical portion to which the filter joint has. End opposite to the bottom portion in the axial direction of the cylindrical portion to which the filter joint has is, according to claim 1 or 2 in which is open in the axial direction without contact with other members all around Volumetric pump. The positive displacement pump according to any one of claims 1 to 3, wherein the cylindrical portion of the filter joint surrounds a radial outer wall of the pump cover in a cylindrical shape. The positive displacement pump according to any one of claims 1 to 4 , wherein a rotation axis (O1) of the inner rotor and the outer rotor is coaxial with a center of the cylindrical portion of the filter joint.

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