JP4447332B2 - Fuel pump - Google Patents

Description

  The present invention relates to a fuel pump that sucks fuel such as gasoline and boosts the pressure, and discharges the boosted fuel. In particular, the present invention relates to a technique for improving the boosting performance of a fuel pump.

There is known a fuel pump including a substantially disc-shaped impeller and a casing that rotatably accommodates the impeller. With reference to FIG. 13, typical fuel pump configurations are listed below.
In a region extending in the circumferential direction at a predetermined distance from the outer periphery of the impeller 20, recess groups 20 a that repeat in the circumferential direction are formed on both the front and back surfaces of the impeller 20.
-The bottoms of the recesses 20a on the front and back sides communicate with each other.
The recess group 20 a is separated from the outer peripheral surface of the impeller 20 by the outer peripheral wall of the impeller 20.
A suction side groove that extends from an upstream end to a downstream end of a region facing the recess group 20a of the impeller 20 on the inner surface of the casing facing the surface of the impeller 20 and communicates with the fuel suction port at the upstream end. 102 is formed.
-On the inner surface of the casing facing the back surface of the impeller 20, a region facing the recess group 20a of the impeller 20 extends from the upstream end to the downstream end, and the discharge side groove that communicates with the fuel discharge port at the downstream end Is formed.
The outer side surface 190 (that is, the outer side surface near the upstream end) of the inlet side groove in the vicinity of the fuel inlet is formed substantially perpendicular to the impeller 20 at the position of the outer peripheral end 20e of the recess group 20a of the impeller 20. Yes.
The inner side surface 192 of the inlet side groove in the vicinity of the fuel inlet port (that is, the inner side surface in the vicinity of the upstream end) is formed substantially perpendicular to the impeller 20 at a position near the inner peripheral end 20f of the recess group 20a of the impeller 20. Has been.

In the fuel pump configured as described above, fuel is sucked from the fuel suction port when the impeller rotates. The sucked fuel flows in the direction of the impeller along the outer side surface and the inner side surface of the inlet side groove near the upstream end. Thereby, the fuel sucked from the fuel suction port is introduced into the recess of the impeller. In the casing, a centrifugal force caused by the rotation of the impeller acts on the fuel, and a swirling flow is generated across the recess on the surface side of the impeller and the inlet side groove. This swirling flow enters the inner peripheral side in the surface side recess from the inlet side groove, flows in the surface side recess from the inner peripheral side to the outer peripheral side along the surface side recess, and the outer peripheral side in the surface side recess. A flow path returning from the inlet to the inlet side groove is formed. In addition, a swirling flow is also generated across the back side recess and the discharge port side groove. This swirling flow flows along the back side recess from the inner periphery side toward the outer periphery side, and forms a flow path returning from the outer periphery side in the back side recess to the discharge port side groove.
The sucked fuel advances downstream along the suction side groove and the discharge side groove while forming a swirling flow. In this process, the pressure of the fuel is increased, and the pressurized fuel is discharged out of the casing from the fuel discharge port.
Patent Document 1 discloses an example of a conventional fuel pump.
International Publication No. 98/09082 Pamphlet

When the swirl flow is less likely to occur in the fuel pump, the boosting performance does not increase. It is preferable to improve the boosting performance by generating a swirl flow well.
In the conventional fuel pump (the fuel pump shown in FIG. 13), in the vicinity of the upstream end of the suction side groove, the fuel sucked from the fuel suction port is recessed along the outer side surface and the inner side surface of the impeller. It will flow toward. In this case, the fuel flowing toward the surface side recess of the impeller collides with the swirling flow returning from the outer peripheral side in the surface side recess to the inlet side groove. For this reason, in the vicinity of the upstream end of the inlet side groove, the swirl flow over the impeller surface side recess and the inlet side groove is disturbed. Thereby, there existed a problem that the pressure | voltage rise performance of a fuel pump fell.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique capable of improving the boosting performance of a fuel pump.

The fuel pump of the present invention includes an impeller in which a plurality of recess groups are formed in an annular shape, and a casing that rotatably accommodates the impeller. The recess group of the impeller is formed in a region extending in the circumferential direction at a predetermined distance from the outer periphery of the impeller, and is separated from the outer peripheral surface of the impeller by the outer peripheral wall of the impeller. In the “region facing the group of recesses of the impeller” of the casing, an inlet side groove communicating with the fuel inlet and an outlet side groove communicating with the fuel outlet are formed. Further, the “outer side surface in the vicinity of the upstream end” of the inlet side groove is formed by a substantially vertical surface formed substantially perpendicular to the impeller at a position inside the outer peripheral end of the recess group of the impeller, and the substantially vertical surface. And an inclined surface that is inclined toward the outer peripheral end of the recess group of the impeller. The substantially vertical surface has a portion extending upstream from the downstream end of the opening of the fuel inlet. The portion of the substantially vertical surface is formed at a substantially intermediate position in the radial direction of the recess group of the impeller.

  In the fuel pump having the above configuration, the substantially vertical surface constituting the outer side surface of the inlet side groove near the upstream end is formed at a position inside the outer peripheral end of the recess group of the impeller. For this reason, the fuel flowing in the direction of the impeller along the substantially vertical plane is guided so as to enter the inner peripheral side in the surface side recess of the impeller. The fuel that has entered the surface-side recess of the impeller flows along the surface-side recess to the outer peripheral side, and then returns to the inlet side groove from the outer peripheral side in the surface-side recess. The fuel that has returned to the inlet side groove flows in the anti-impeller direction along the inclined surface, and merges with the fuel that flows in the impeller direction along the substantially vertical surface. Since the inclined surface is provided, the fuel flowing in the anti-impeller direction returning from the surface side recess to the inlet side groove can smoothly merge with the fuel flowing in the impeller direction along the substantially vertical surface. An undisturbed swirling flow can be formed in the vicinity of the upstream end of the inlet side groove. The fuel pump of the present invention is excellent in boosting performance.

The inclined surface described above may be a tapered surface inclined at a substantially constant inclination angle.
In this case, the fuel flowing in the anti-impeller direction along the tapered surface and the fuel flowing in the impeller direction along the substantially vertical surface can smoothly merge.

Further, the inclined surface described above may be an R surface whose inclination angle increases from the substantially vertical surface toward the outer peripheral end of the recess group of the impeller.
Also in this case, it is possible to generate a swirling flow without any disturbance.

The inlet-side groove described above may be formed such that the groove width becomes narrower inward from the position downstream of the upstream end by a specific distance toward the upstream end. In this case, the casing inner surface facing the surface of the impeller has the following three configurations: (1) a region facing the recess group of the impeller downstream from the upstream end of the inlet side groove by the specific distance described above. A special groove that extends from the position of at least the upstream end of the inlet side groove, (2) communicates with the inlet side groove outside the inlet side groove, and (3) has a configuration of a predetermined depth or less. Can be formed.
The “below the predetermined depth” means that the groove has a depth that is so small that the fuel sucked from the fuel inlet and flowing in the impeller direction does not enter.
This special groove functions to receive high-pressure fuel that has returned from the downstream end to the upstream end of the inlet side groove while remaining in the recess of the impeller. Since the special groove and the inlet side groove communicate with each other, the high-pressure fuel received in the special groove is introduced into the inlet side groove. By providing the special groove, noise when the fuel pump operates can be suppressed. In addition, since the special groove is provided outside the inlet side groove, the high-pressure fuel flowing outward by centrifugal force can be well received, and the generation of noise can be effectively prevented.

  The above-mentioned special groove may be formed so that the groove width becomes wider from the upstream side of the inlet side groove toward the upstream end of the inlet side groove from the position downstream of the specific distance.

The special groove described above may extend further upstream than the upstream end of the inlet side groove.
In this way, generation of noise can be effectively prevented.

The inlet side groove and the special groove are only between a position downstream from the upstream end of the inlet side groove by a distance less than the specified distance and a position downstream from the upstream end of the inlet side groove by the specified distance. You may make it communicate.
In this way, the fuel can be introduced from the special groove into the inlet side groove further downstream.

(Embodiment 1) A fuel pump having the following configuration is also a creation of the present invention.
In a region extending in the circumferential direction at a predetermined distance from the outer periphery of the impeller, a group of recesses that repeat in the circumferential direction is formed on both the front and back surfaces of the impeller.
-The bottoms of the front and back recesses communicate with each other.
-The recess group is separated from the outer peripheral surface of the impeller by the outer peripheral wall of the impeller.
On the inner surface of the casing facing the impeller surface, an inlet side groove that extends from the upstream end to the downstream end in a region facing the recess group of the impeller and communicates with the fuel intake port at the upstream end is formed. ing.
-On the inner surface of the casing facing the rear surface of the impeller, a region facing the group of recesses of the impeller extends from the upstream end to the downstream end, and a discharge side groove that communicates with the fuel discharge port is formed at the downstream end. ing.
The inlet-side groove is formed such that the groove width becomes narrower inward from the position downstream of the upstream end by a specific distance toward the upstream end.
The casing inner surface facing the surface of the impeller has the following three configurations: (1) a region facing the group of recesses in the impeller is located downstream from the upstream end of the inlet side groove by the specific distance described above. A special groove is formed that extends to at least the upstream end of the inlet-side groove, (2) communicates with the inlet-side groove outside the inlet-side groove, and (3) is a predetermined depth or less. ing.
That is, the fuel pump in which the above-mentioned special groove is formed is very excellent regardless of the presence or absence of a substantially vertical plane and an inclined plane following the plane.

First Embodiment An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the fuel pump 10. The fuel pump 10 is for an automobile, operates in a state immersed in the fuel in the fuel tank, and pumps the fuel to the engine.
As shown in FIG. 1, the fuel pump 10 includes a motor unit 70 and a pump unit 12.
The motor unit 70 includes a housing 72, a motor cover 73, magnets 74 and 75, a rotor 76, and the like. The housing 72 is formed in a substantially cylindrical shape. The motor cover 73 is fixed to the housing 72 by caulking the upper end 72a of the housing 72 (the upper and lower sides in FIG. 1 are the upper and lower sides of the fuel pump 10) toward the inner diameter side. The motor cover 73 is formed with a discharge port 73a that opens upward. Magnets 74 and 75 are fixed to the inner wall of housing 72. The rotor 76 includes a main body 77 and a shaft 78 that penetrates the main body 77 up and down. The main body 77 includes an iron core 79 fixed to the shaft 78, a coil (not shown) wound around the iron core 79, and a resin portion 80 that fills the periphery of the coil. An upper end portion 78 a of the shaft 78 is rotatably attached to the motor cover 73 via a bearing 81. A lower end portion 78 b of the shaft 78 is rotatably attached to the pump cover 14 of the pump portion 12 via a bearing 82.

The pump unit 12 includes a casing 18 and an impeller 20. The casing 18 is a combination of the pump cover 14 and the pump body 16.
The impeller 20 has a substantially disk shape. FIG. 2 shows a plan view of the impeller 20. As shown in FIG. 2, a plurality of recesses 20 a arranged in the circumferential direction are formed on the outer peripheral portion of the impeller 20. At the center of the impeller 20, an engagement hole 20c having a substantially D-shaped cross section perpendicular to the axis passing through in the thickness direction is formed.
3 is a cross-sectional view taken along line III-III in FIG. As well shown in FIG. 3, the recesses 20a are formed on both upper and lower (front and back) surfaces of the impeller 20, and the recesses 20a are communicated with each other through a communication hole 20b at the bottom. The recess group 20 a is separated from the outer peripheral surface of the impeller 20 by the outer peripheral wall 20 d of the impeller 20.

As shown in FIG. 1, a circular recess 14 a is formed on the impeller side surface (that is, the lower surface) of the pump cover 14 when viewed in plan. The diameter of the recess 14 a is the same as the diameter of the impeller 20. The recess 14 a has the same depth as the thickness of the impeller 20. The impeller 20 is rotatably fitted in the recess 14a.
The casing 18 (the pump cover 14 and the pump body 16) is fixed to the housing 72 by the lower end 72b of the housing 72 being crimped inward while the impeller 20 is assembled in the recess 14a of the pump cover 14. The shaft 78 of the rotor 76 is inserted in a state where the shaft 78 of the rotor 76 is engaged with the engagement hole 20c of the impeller 20 further below the portion supported by the bearing 82. For this reason, when the rotor 76 rotates, the impeller 20 also rotates with it. Between the lower end of the shaft 78 and the pump body 16, a thrust bearing 33 for receiving the thrust load of the rotor 76 is interposed.

  FIG. 4 is a plan view of the pump cover 14 as viewed from the impeller 20 side (that is, as viewed from the lower side of FIG. 1). A substantially C-shaped groove 24 is formed on the bottom surface of the recess 14a of the pump cover 14 when viewed in plan. The groove 24 extends in a region facing the recess group 20a of the impeller 20 incorporated in the recess 14a. In FIG. 4, reference numeral 24 a is an upstream end of the groove 24, and reference numeral 24 b is a downstream end of the groove 24. The groove 24 communicates with the fuel discharge port 26 at the downstream end 24b. The fuel discharge port 26 is formed on the upper surface of the pump cover 14 (upper surface in FIG. 1). Hereinafter, the groove 24 will be referred to as a discharge port side groove.

FIG. 5 is a plan view of the pump body 16 viewed from the impeller 20 side (ie, viewed from the upper side of FIG. 1). A substantially C-shaped groove 30 is formed on the surface 16a on the impeller 20 side of the pump body 16 (that is, the upper surface in FIG. 1) when viewed in plan. The groove 30 extends in a region facing the recess group 20 a of the impeller 20. That is, it is formed in a region facing the discharge port side groove 24 of the pump cover 14 with the impeller 20 interposed therebetween. Reference numeral 30 a in FIG. 5 is an upstream end of the groove 30, and reference numeral 30 b is a downstream end of the groove 30.
The groove 30 is composed of a first groove 100 extending upstream from the downstream end 30 b and a second groove 102 extending further upstream from the upstream end 100 a of the first groove 100. A range H1 in FIG. 5 shows a region where the first groove 100 extends, and a range H2 shows a region where the second groove 102 extends. The first groove 100 is shallower than the second groove 102. The first groove 100 has a substantially constant depth. The first groove 100 is provided with a through hole 104 penetrating the pump body 16 vertically (up and down in FIG. 1). This through-hole 104 functions as a vapor removal. The second groove 102 gradually becomes deeper from the upstream end 100a of the first groove toward the upstream. The second groove 102 communicates with the fuel inlet 31 at its upstream end 30a. The fuel inlet 31 is formed on the lower surface of the pump body 16 (the lower surface in FIG. 1). As shown well in FIG. 5, when the pump body 16 is viewed in plan, a part of the fuel inlet 31 can be visually recognized. Hereinafter, the groove 30 will be referred to as an inlet side groove.

The shape of the second groove 102 of the inlet side groove 30 will be described in a little more detail. 6 shows a cross-sectional view taken along line VI-VI in FIG. FIG. 7 shows a cross-sectional view taken along line VII-VII in FIG.
FIG. 6 shows the outer side surfaces 120 and 122 and the inner side surface 124 of the second groove 102 in the vicinity of the upstream end 30a. The outer side surface of the second groove 102 is formed so as to be inclined toward the outer peripheral end 20e of the recess 20a of the impeller 20 from the substantially vertical surface 120 formed substantially perpendicular to the impeller 20 and the impeller 20. And an inclined surface 122.
The substantially vertical surface 120 is formed inside the outer peripheral end 20 e of the recess 20 a of the impeller 20. The substantially vertical surface 120 is formed at an intermediate position in the radial direction of the recess 20 a of the impeller 20. That is, S1 and S2 in FIG. 6 are equal. In FIG. 7, a substantially vertical surface 120 is also shown. Reference numeral 128 in FIG. 7 is the bottom surface of the second groove 102.
The inclined surface 122 is a tapered surface that is inclined at a substantially constant inclination angle. As shown in FIG. 5, the tapered surface 122 is formed in a substantially triangular shape when seen in a plan view. The width of the tapered surface 122 (the width in the radial direction of the impeller 20) gradually increases from the downstream end of the tapered surface 122 toward the upstream side, and is maximum at a position corresponding to the downstream end of the special groove 130 described later. become. The width of the tapered surface 122 gradually decreases from the position corresponding to the downstream end of the special groove 130 toward the upstream side.
As shown in FIG. 6, the inner side surface 124 is formed substantially perpendicular to the impeller 20.

An arrow D1 in FIG. 6 shows a state in which the fuel sucked from the fuel suction port 31 flows upward. The fuel flowing upward indicated by the arrow D1 enters the inner peripheral side of the recess 20a of the impeller 20 from the second groove 102, as indicated by the arrow D2, and swirls at the recess 20a to be outer peripheral side of the recess 20a. To form a swirling flow returning to the second groove 102. The fuel that has returned to the second groove 102 flows downward along the tapered surface 122, as indicated by the arrow D3, and joins the fuel (arrow D1) that is sucked from the fuel inlet 31 and directed upward.
FIG. 13 shows the flow of fuel in the vicinity of the fuel inlet of a conventional fuel pump. In FIG. 13, the same members as those in the present embodiment are denoted by the same reference numerals. The outer peripheral side surface 190 of the second groove 102 is a vertical surface extending toward the outer peripheral end 20 e of the recess group 20 a of the impeller 20. In this case, the fuel that is sucked and flows upward (indicated by arrow D4) and the fuel that returns from the recess 20a of the impeller 20 to the second groove 102 (indicated by arrow D5) collide with each other. For this reason, it becomes difficult to generate a swirling flow, and a turbulent flow as indicated by an arrow D6 is formed.

It is known that when the swirl flow is easily generated, the pressure boosting performance of the fuel pump 10 is improved. In this embodiment, the substantially vertical surface 120 and the tapered surface 122 constitute the outer side surface in the vicinity of the upstream end of the second groove 102, and therefore, a swirl flow without turbulence can be generated.
FIG. 8 is a graph showing the flow rate of the fuel pump 10 of this embodiment. The horizontal axis is the fuel temperature, and the vertical axis is the flow rate. Scale lines on the horizontal axis are attached at intervals of 5 ° C. The scale lines on the vertical axis are attached at intervals of 10 (L (liter) / h (time)). A graph G1 in the figure is a graph of the fuel pump 10 of this embodiment, and a graph G2 is a graph of a conventional fuel pump. In the conventional fuel pump, the flow rate decreases when the fuel temperature exceeds 37 degrees. In contrast, the fuel pump 10 of the present embodiment can maintain a large flow rate up to around 45 degrees. The fuel pump 10 of the present embodiment can secure a flow rate that is about 6 (L / h) higher than the conventional one when boosting high-temperature fuel exceeding 55 ° C.
The fuel pump 10 of the present embodiment can generate an undisturbed swirling flow in the vicinity of the fuel inlet 31 and can improve the inflow performance of the fuel into the casing 18. Thereby, generation | occurrence | production of a negative pressure can be suppressed. The fuel pump 10 of the present embodiment is very excellent in the pressure increasing performance.

As shown in FIG. 5, the second groove 102 has a width (a width in the radial direction of the impeller 20) at a position downstream of the upstream end 30a by a predetermined distance (a position corresponding to the downstream end of the special groove 130). Is the maximum. The width of the second groove 102 becomes narrower toward the inner peripheral side from the position corresponding to the downstream end of the special groove 130 toward the upstream side.
The special groove 130 is a groove having a slight depth. Referring to FIG. 7, it can be seen that the upper surface 16a of the pump body 16 is slightly cut to form the special groove 130. The special groove 130 is formed in a region facing the recess group 20 a of the impeller 20. The special groove 130 communicates with the second groove 102 outside the second groove 102. The groove width of the special groove 130 (groove width in the radial direction of the impeller 20) gradually increases as the groove width of the second groove 102 moves upstream from the maximum position. The groove width of the special groove 130 becomes maximum at the upstream end 30 a of the inlet side groove 30.
The special groove 130 receives the high-pressure fuel returned from the downstream end 30b of the inlet side groove 30 to the upstream end 30a while remaining in the recess 20a of the impeller 20. If there is no special groove 130, the high-pressure fuel remaining in the recess group 20a of the impeller 20 will be ejected into the second groove 102, and a large noise will be generated at that time. In this embodiment, since the special groove 130 is provided, noise can be suppressed.

FIG. 9 is a graph with frequency on the horizontal axis and noise level on the vertical axis. The solid line graph is for the fuel pump 10 of this embodiment. The noise level is very low. The broken line graph is for the fuel pump of WO 98/09082 filed by the present applicant and published internationally. This internationally disclosed fuel pump has very little noise. The fuel pump 10 of the present embodiment can be suppressed to a noise level equivalent to that of a conventional fuel pump with very little noise. In addition, depending on the frequency range, the noise can be suppressed to be smaller than that of the conventional fuel pump.
The special groove 130 has a groove width that narrows outward as it goes downstream. Thereby, the 2nd groove | channel 102 can be ensured large. However, the special groove 130 has an outer portion extending to the downstream side. When the high pressure fuel is ejected into the special groove 130, the high pressure fuel flows outward due to the centrifugal force generated by the rotation of the impeller 20. The shape of the special groove 130 is considered so that the high-pressure fuel ejected outward can be received.

  As well shown in FIG. 6, when the impeller 20 rotates, a swirl flow that spans the recess 20 a on the lower side of the impeller 20 and the inlet side groove 30 of the pump body 16 is generated. The fuel flows along the inlet side groove 30 while turning and is pressurized. When the pressure of the fuel is increased along the inlet side groove 30, the fuel is sucked from the fuel inlet 31 of the pump body 16 accordingly. The fuel pressurized by the inlet side groove 30 passes through the communication hole 20b of the impeller 20 and merges with the fuel present in the recess 20a on the upper side of the impeller 20. The fuel in the casing 18 is also boosted along the discharge port side groove 24. A swirling flow is also generated across the recess 20a on the upper side of the impeller 20 and the discharge port side groove 24. The fuel whose pressure has been increased in the discharge port groove 24 and the fuel whose pressure has been increased in the suction side groove 30 which has joined the fuel are sent out from the fuel discharge port 26 (see FIG. 4) into the housing 72 of the motor unit 70. The fuel fed into the housing 72 flows upward in the housing 72 and is discharged from the discharge port 73 a of the motor cover 73.

The fuel pump 10 of this embodiment described above can form a swirling flow without any disturbance in the vicinity of the fuel inlet 31. The fuel pump 10 of the present embodiment is very excellent in the pressure increasing performance. Moreover, since the inflow performance of the fuel into the casing 18 is good, generation of negative pressure can be suppressed.
Moreover, since the special groove 130 is provided, generation of noise can be suppressed. Since the special groove 130 is provided outside the inlet-side groove 30, it is possible to receive well the fuel that is jetted into the special groove 130 outward due to centrifugal force. Generation of noise can be effectively prevented.

(Second embodiment)
Here, the description will focus on the differences from the first embodiment. In this embodiment, the shape of the inclined surface (indicated by reference numeral 122 in the first embodiment) of the inlet side groove 30 is different from that of the first embodiment. FIG. 10 shows the inclined surface 200 of this embodiment well.
The substantially vertical surface 120 is formed at an intermediate position in the radial direction of the recess 20a of the impeller 20 (that is, S1 and S2 are equal) as in the first embodiment. The inclined surface 200 is an R surface whose inclination angle increases from the upper end of the substantially vertical surface 120 toward the outer peripheral side end 20e of the recess 20a.
Even if the inclined surface 200 has an R shape, the same effect as in the first embodiment can be obtained. That is, the fuel sucked from the fuel inlet 31 (arrow D1 ′) and the fuel swirled along the recess 20a and the R plane 200 (arrows D2 ′ and D3 ′) smoothly merge. Thereby, a swirl flow without turbulence can be formed, and the boosting performance is improved.

(Third embodiment)
Here, the description will focus on the differences from the first embodiment. In this embodiment, the shape of the special groove (indicated by reference numeral 130 in the first embodiment) is different from that of the first embodiment. In FIG. 11, the top view of the pump body 16 of a present Example is shown.
In the first embodiment, the upstream end 30a of the inlet side groove 30 and the upstream end of the special groove 130 are formed in the same phase (see FIG. 5). On the other hand, the special groove 230 of the present embodiment extends further upstream than the upstream end 30a of the inlet side groove 30 (see FIG. 11). The special groove 230 is formed such that its outer side surface 230a extends upstream from the first embodiment.
If the special groove 230 is formed to extend upstream as in this embodiment, noise can be further suppressed.
In the present embodiment, the inner side 230b of the special groove 230 is formed in the same manner as in the first embodiment, but the inner side 230b may be further extended upstream.

(Fourth embodiment)
Here, the description will focus on the differences from the first embodiment. In this embodiment, the shape of the special groove (indicated by reference numeral 130 in the first embodiment) is different from that of the first embodiment. In FIG. 12, the top view of the pump body 16 of a present Example is shown.
As shown in FIG. 12, a partition wall 332 may be provided between the second groove 102 and the special groove 330, and a portion where the second groove 102 and the special groove 330 communicate with each other may be made smaller than in the first embodiment. The partition wall 332 forms the same surface as the upper surface 16 a of the pump body 16. The partition wall 332 is formed so as to extend from the upstream end 30 a to the downstream side along the outer side surface of the second groove 102. Only the vicinity of the downstream end of the special groove 330 communicates with the second groove 102.
Even in this embodiment, noise can be suppressed to the same extent as in the first embodiment. Further, in this embodiment, since only the vicinity of the downstream end of the special groove 330 communicates with the second groove 102, the fuel received by the special groove 330 is introduced into the second groove 102 further downstream. Can do.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is a longitudinal cross-sectional view of a fuel pump. It is a top view of an impeller. It is the III-III sectional view taken on the line of FIG. It is a top view of a pump cover. It is a top view of a pump body. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. It is the VII-VII sectional view taken on the line of FIG. It is the graph which showed the relationship between fuel temperature and flow volume. It is the graph which showed the noise level. It is sectional drawing for demonstrating the shape in the upstream end vicinity of the inlet side groove | channel of the fuel pump which concerns on 2nd Example. It is a top view of the pump body which concerns on 3rd Example. It is a top view of the pump body which concerns on 4th Example. It is sectional drawing for demonstrating the shape in the upstream end vicinity of the inlet side groove | channel of the conventional fuel pump.

Explanation of symbols

10: pump 12: pump part 14: pump cover 16: pump body 18: casing 20: impeller, 20a: recess, 20b: communication hole, 20c: engagement hole, 20d: outer peripheral wall 24: discharge side groove, 24a: Upstream end, 24b: Downstream end 26: Discharge port 30: Suction side groove, 30a: Upstream end, 30b: Downstream end 31: Suction port 33: Thrust bearing 70: Motor part 72: Housing, 72a: Upper end, 72b: Lower end 73 : Motor cover, 73a: Discharge port 74, 75: Magnet 76: Rotor 77: Main body 78: Shaft, 78a: Upper end portion, 78b: Lower end portion 79: Iron core, 79a: Upper end surface 80: Resin portion 81, 82: Bearing 100: first groove 102 in the inlet side groove 102: second groove in the inlet side groove 104: vapor removal hole 120: substantially vertical surface 122: inclined surface 124: inner side surface 13 : Special groove

Claims (7)

An impeller having a plurality of recess groups formed in an annular shape;
A casing for rotatably accommodating the impeller,
The recess group of the impeller is formed in a region extending in the circumferential direction at a predetermined distance from the outer periphery of the impeller, and is separated from the outer peripheral surface of the impeller by the outer peripheral wall of the impeller.
In the "region facing the recess group of the impeller" of the casing, a suction side groove that communicates with the fuel suction port and a discharge side groove that communicates with the fuel discharge port are formed.
The “outer side surface in the vicinity of the upstream end” of the inlet side groove includes a substantially vertical surface formed substantially perpendicular to the impeller at a position inside the outer peripheral end of the recess group of the impeller, and the impeller from the substantially vertical surface. inclined toward the outer peripheral end of the concavities has closed the inclined surface is formed,
The substantially vertical surface has a portion extending upstream from the downstream end of the opening of the fuel inlet,
The fuel pump according to claim 1, wherein the portion of the substantially vertical surface is formed at a substantially intermediate position in the radial direction of the recess group of the impeller .   2. The fuel pump according to claim 1, wherein the inclined surface is a tapered surface inclined at a substantially constant inclination angle.   2. The fuel pump according to claim 1, wherein the inclined surface is an R surface having an inclination angle that increases from the substantially vertical surface toward the outer peripheral end of the recess group of the impeller. An impeller having a plurality of recess groups formed in an annular shape;
A casing for rotatably accommodating the impeller,
In the "region facing the recess group of the impeller" of the casing, a suction side groove that communicates with the fuel suction port and a discharge side groove that communicates with the fuel discharge port are formed.
The “outer side surface in the vicinity of the upstream end” of the inlet side groove includes a substantially vertical surface formed substantially perpendicular to the impeller at a position inside the outer peripheral end of the recess group of the impeller, and the impeller from the substantially vertical surface. And an inclined surface formed to be inclined toward the outer peripheral end of the recess group of
The inlet side groove is formed such that the groove width becomes narrower inwardly from the position downstream of the upstream end by a specific distance toward the upstream end,
The casing inner surface facing the surface of the impeller has the following three configurations:
(1) The region facing the recess group of the impeller extends from the position downstream of the specific distance from the upstream end of the inlet side groove to at least the upstream end of the inlet side groove. (2) The inlet Communicating with the inlet side groove on the outside of the side groove, (3) below a predetermined depth,
A fuel pump, characterized in that a special groove is formed.   The special groove is formed so that a groove width becomes wider from a position downstream of the specific distance from the upstream end of the inlet side groove toward the upstream end of the inlet side groove. 4 fuel pump. The special grooves, the fuel pump according to claim 4 or 5, characterized in that extends further upstream than the upstream end of the inlet groove. The inlet side groove and the special groove are located between a position downstream of the upstream end of the inlet side groove by a distance less than the specific distance and a position downstream of the upstream end of the inlet side groove by the specific distance. The fuel pump according to any one of claims 4 to 6 , wherein only the fuel pump is in communication.

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