JP2007187010A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve pump efficiency by making fuel smoothly flow into a blade groove along a rear area of the blade groove. <P>SOLUTION: In the fuel pump, the plurality of blade grooves 36 are formed on an outer circumference edge part of an impeller 30 formed in a disk shape in a rotary direction. Fuel sucked from a fuel inlet 200 provided on a pump case 20 is pressurized in pressurizing passages 202, 203 on both sides in a thickness direction of the impeller 30 by rotation of the impeller. A connection wall surface 21 of a connection passage 201 connecting the fuel inlet 200 and the pressurizing passage 202 is connected to the pressurizing passage 202 with gradual rise-up toward the pressurizing passage 202 from the fuel inlet 200. Angle α formed by a inclined straight line 108 connecting a pressurizing passage side end 21b and a fuel inlet side end 21a of the connection wall 21, and a segment 114 reaching the inclined straight line 108 from a center in the thickness direction of the rear area 37 in the rear in the rotation direction of the blade grooves 36 through a fuel inlet side end 37d which is one of both ends in the thickness direction of the rear area 37, in the front in the rotation direction is set to 90°≤α≤130°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel pump that pressurizes fuel sucked by rotation of an impeller having a plurality of blade grooves formed in the rotation direction.

  2. Description of the Related Art Conventionally, a fuel pump that forms a plurality of blade grooves in the rotation direction of a disk-shaped impeller and pressurizes fuel sucked into a pressure increasing passage when the impeller rotates (see, for example, Patent Document 1). In such a fuel pump, for example, a higher discharge pressure is required due to a demand for improving atomization of fuel spray injected from a fuel injection valve. If the current supplied to the motor unit of the fuel pump is increased, the discharge pressure of the fuel pump can be increased, but there is a problem that the power consumption of the fuel pump increases.

Therefore, it is conceivable to increase the discharge pressure of the fuel pump without increasing the power consumption of the motor unit as much as possible by improving the pump efficiency of the pump unit. For example, Patent Document 1 attempts to improve the pump efficiency of the pump unit by gradually reducing the passage area from the fuel inlet toward the pressure increasing passage, thereby improving the efficiency of the fuel pump. Here, since the efficiency of the fuel pump is expressed by (motor efficiency) × (pump efficiency), if the pump efficiency is improved, the efficiency of the fuel pump is improved. The motor efficiency and the pump efficiency are: the drive current supplied to the motor part of the fuel pump is I, the applied voltage is V, the torque of the motor part is T, the rotational speed of the motor part is N, and the discharge pressure of the fuel discharged from the fuel pump Is P and the fuel discharge amount is Q, (motor efficiency) = (T × N) / (I × V), (pump efficiency) = (P × Q) / (T × N). Therefore, (fuel pump efficiency) = (motor efficiency) × (pump efficiency) = (P × Q) / (I × V). If the pump efficiency is improved, the fuel discharge pressure can be increased or the fuel discharge amount can be increased without increasing the power consumption of the fuel pump as much as possible.
However, in addition to improving the pump efficiency by gradually reducing the passage area from the fuel inlet toward the pressure increasing passage as in Patent Document 1, there is a demand for increasing the fuel discharge pressure or increasing the fuel discharge amount. Accordingly, there is a demand for further improving pump efficiency.

Japanese Unexamined Patent Publication No. 7-1899752

  The present invention has been made to solve the above problems, and an object thereof is to provide a fuel pump that improves pump efficiency.

  According to the first to fourth aspects of the present invention, at least the fuel inlet side in the thickness direction of the impeller on the rear surface behind the rotation direction forming the blade groove rotates from the center in the thickness direction of the impeller toward the end portion on the fuel inlet side. The line segment connecting the radially inner end and the radially outer end of the rear surface is the radial direction with respect to a straight line that is inclined forward in the direction and extends radially outward from the radially inner end of the rear surface to the radial direction of the impeller. As it goes outward, it tilts backward in the direction of rotation. The connecting wall surface connecting the fuel inlet and the pressure increasing passage gradually rises from the fuel inlet toward the pressure increasing passage and approaches the pressure increasing passage. As described above, the fuel inlet side in the thickness direction of the impeller on the rear surface of the blade groove is an inclined surface that is inclined forward in the rotational direction from the center in the thickness direction toward the fuel inlet side in the thickness direction. The energy component that the swirling flow of the fuel receives from the blade groove toward the front in the rotation direction increases, and the pitch in the rotation direction of the swirling flow decreases. As a result, the number of times the swirling flow enters and exits the blade groove while flowing through the pressure increasing passage increases, so that the fuel pressure increasing efficiency is improved.

In this configuration, when the fuel flows toward the blade groove while being narrowed down while being guided to the connection wall surface from the fuel inlet, the fuel flows into the blade groove along the rear surface of the blade groove of the impeller. It is desirable to improve pump efficiency. Here, an inclined straight line connecting the fuel inlet side end of the connection wall surface and the boost passage end and a line segment that reaches the inclined straight line from the center in the thickness direction of the rear surface through the fuel inlet side end of the rear surface are forward in the rotational direction. If the angle α to be formed is 90 °> 痾, the fuel flow guided from the fuel inlet to the connecting wall surface and flowing into the impeller blade groove collides with the rear surface of the impeller blade groove rotating at high speed at a large angle. To do. Further, when α> 130 °, the difference between the fuel flow guided to the connecting wall surface and the fuel flow toward the blade groove and the rear surface of the blade groove becomes large, so that the fuel hardly flows into the blade groove.
Accordingly, in the invention described in claims 1 to 4, by setting 90 ° ≦ α ≦ 130 °, the fuel smoothly flows into the blade groove along the rear surface of the blade groove with respect to the impeller rotating at high speed. To do. As a result, pump efficiency is improved.

  In the invention according to claim 2, since the rear surface is inclined forward in the rotational direction from the center in the thickness direction toward both sides in the thickness direction, the swirl flow of fuel flowing out from the blade grooves on both sides in the thickness direction of the blade grooves The energy component received from the blade groove toward the front in the rotational direction increases, and the pitch in the rotational direction of the swirl flow decreases. As a result, the number of times the swirling flow enters and exits the blade groove while flowing through the pressure increasing passages on both sides in the thickness direction of the impeller increases, so that the fuel pressure increasing efficiency is improved and the pump efficiency is improved.

By the way, when the rising angle β of the inclined straight line from the fuel inlet side end of the connecting wall surface to the boosting passage side end which is the rising angle of the connecting wall surface from the fuel inlet to the boosting passage is 10 °> β, the fuel on the connecting wall surface Since the angle of the corner near the inlet side end is close to 90 °, separation occurs in the fuel flow from the fuel inlet toward the connection wall surface near the fuel inlet side end of the connection wall surface, and the energy of the fuel flow is reduced. Also, if β> 30 °, the passage area near the fuel inlet side end of the connection wall surface becomes large, and a fuel flow flowing from the fuel inlet to the connection wall surface side causes a flow that stays toward the boosting passage. The energy of the flow is reduced. Thus, when the energy of the fuel flow is reduced, the pump efficiency is lowered.
Therefore, in the invention described in claim 3, by setting 10 ° ≦ β ≦ 30 °, it is possible to prevent the fuel flow from the fuel inlet toward the connection wall surface from being separated and stayed. Thereby, reduction of the energy of a fuel flow can be suppressed and pump efficiency can be improved.

Further, in the inclined surface that is inclined forward in the rotational direction from the center in the thickness direction of the rear surface toward the end in the thickness direction, a line segment that connects the center in the thickness direction and the end in the thickness direction, If the angle γ formed by the straight line extending forward in the rotational direction along the circumferential direction from the center is 40 °> γ, the direction of the fuel flow flowing into the blade groove changes suddenly forward in the rotational direction. The energy of the swirl flow is reduced. Further, when γ> 60 °, the energy component that the swirling flow receives from the blade groove toward the front in the rotation direction when it flows out of the blade groove becomes small. As a result, since the pitch in the rotational direction of the swirl flow is increased, the interval between the blade grooves until the swirl flow flows out of the blade groove and flows into the next blade groove behind the rotation direction is increased. That is, the number of times the swirling flow enters and exits the blade groove while flowing through the pressure increasing passage is reduced, so that the fuel is not sufficiently pressurized.
Therefore, in the invention described in claim 4, by setting 40 ° ≦ γ ≦ 60 °, the reduction of the energy of the swirling flow flowing out from the blade groove is suppressed, and the swirling flow flows in the blade groove while flowing through the pressure increasing passage. Increases the number of times you enter and exit Thereby, the boosting efficiency of the fuel is improved, and the pump efficiency is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fuel pump according to an embodiment of the present invention is shown in FIG. The fuel pump 10 is an in-tank type turbine pump mounted in a fuel tank of a vehicle, for example, and supplies the fuel in the fuel tank to a fuel injection valve (not shown). The discharge pressure of the fuel pump 10 is set in the range of 0.25 to 1 MPa, the discharge amount is 50 to 250 L / h, and the rotation speed is 4000 to 12000 rpm.

The fuel pump 10 includes a pump unit 12 and a motor unit 13 that rotationally drives the pump unit 12. The housing 14 also serves as a housing for the pump unit 12 and the motor unit 13, and crimps the end cover 16 and the pump case 20.
The pump unit 12 is a turbine pump having pump cases 20 and 22 and an impeller 30. The pump case 22 is press-fitted into the housing 14 and abutted against the step portion 15 of the housing 14 in the axial direction. The pump cases 20 and 22 are case members that rotatably accommodate an impeller 30 as a rotating member. C-shaped pressure increasing passages 202 and 203 (see FIG. 3) are formed between the pump cases 20 and 22 and the impeller 30, respectively. That is, the pressure increasing passages 202 and 203 are formed on both sides in the thickness direction, which is the axial direction of the impeller 30, respectively.

  As shown in FIG. 5, a plurality of blade grooves 36 are formed in the rotation direction on the outer peripheral edge of the impeller 30 formed in a disk shape. When the impeller 30 rotates together with the shaft 51 by the rotation of the armature 50 shown in FIG. 2, the fuel that has flowed into the pressure increasing passages 202 and 203 from the radially outer side of the blade groove 36 forward in the rotational direction is the diameter of the blade groove 36 behind the rotational direction. Flows inward. By repeating such outflow and inflow of the fuel many times between the blade grooves 36, the fuel becomes a swirl flow 300 and is pressurized in the pressure increasing passages 202 and 203. The fuel sucked from the fuel inlet 200 (see FIG. 3) provided in the pump case 20 by the rotation of the impeller 30 is pressurized by the pressure increase passages 202, 203 on both sides in the thickness direction of the impeller 30 by the rotation of the impeller 30, and the pump case 22 is pumped from the discharge port 206 (see FIG. 3) provided to the motor unit 13 side. The fuel pressurized by the pressure increase passage 202 on the fuel inlet 200 side of the impeller 30 passes through the blade groove 36 in the vicinity of the discharge port 206 and moves to the pressure increase passage 203 on the discharge port 206 side. 13 is pumped. The fuel pumped into the motor unit 13 passes through the fuel passage 208 between the permanent magnet 40 and the armature 50 and is supplied to the engine side from the discharge port 210 provided in the end cover 16. An air vent hole 204 (see FIG. 3) provided in the pump case 20 is for exhausting the air contained in the fuel in the pressure increasing passages 202 and 203 to the outside of the fuel pump 10.

Four permanent magnets 40 formed in a quarter arc shape are attached to the inner peripheral wall of the housing 14 on the circumference. The permanent magnet 40 has four magnetic poles having different poles in the rotation direction.
Since the metal cover 68 covers the end of the armature 50 on the impeller 30 side, the rotational resistance of the armature 50 is reduced. A commutator 70 is assembled at the end of the armature 50 opposite to the impeller 30. A shaft 51 as a rotating shaft of the armature 50 is supported by a bearing member 24 housed and supported in the end cover 16 and the pump case 22.

  The armature 50 has a central core 52 at the center of rotation. The shaft 51 is press-fitted into a central core 52 formed in a cylindrical shape having a hexagonal cross section. The six magnetic pole cores 54 are installed on the outer periphery of the central core 52 in the rotational direction, and are fitted and coupled to the central core 52. A bobbin 60 formed of an insulating resin is fitted to the outer periphery of each magnetic pole core 54, and a coil 62 is formed by concentrating windings on the outer periphery of the bobbin 60.

  The end of each coil 62 on the commutator 70 side is electrically connected to the coil terminal 64. The coil terminal 64 corresponds to the rotational direction position of each coil 62, and is fitted and electrically connected to the terminal 74 on the commutator 70 side. The end of the coil 62 opposite to the commutator 70 on the side of the impeller 30 is electrically connected to the coil terminal 66. The six coil terminals 66 are electrically connected to each other by a cover 68.

  The commutator 70 is a cassette type integrally formed. When the shaft 51 is pressed into the central core 52 and the shaft 51 is inserted into the through-hole 71 of the commutator 70 and the commutator 70 is assembled to the armature 50, the terminal protruding to the armature 50 side of the commutator 70 74 is fitted into the coil terminal 64 of the armature 50 and is electrically connected to the coil terminal 64.

The commutator 70 has six segments 72 installed in the rotational direction. The segments 72 are made of, for example, carbon, and the segments 72 are electrically insulated from each other by a gap and an insulating resin material 76.
Each segment 72 is electrically connected to a terminal 74 through an intermediate terminal 73. The insulating resin material 76 integrates the segment 72 (excluding a sliding surface with a brush (not shown)), the intermediate terminal 73, and the terminal 74 by insert molding, whereby the commutator 70 is configured. As the commutator 70 rotates with the armature 50, each segment 72 sequentially contacts the brush. As the commutator 70 rotates and sequentially contacts the brush, the current supplied to the coil 62 is rectified. The permanent magnet 40, the armature 50, the commutator 70 and the brush (not shown) constitute a DC motor.

Next, the passage configuration near the impeller 30 and the fuel inlet 200 will be described in detail.
The impeller 30 is integrally formed in a disc shape with resin. As shown in FIG. 5, the outer periphery of the impeller 30 is surrounded by an annular portion 32, and a plurality of blade grooves 36 are formed in the rotational direction on the inner peripheral side of the annular portion 32. The circumferential width of the blade groove 36 is not uniform. As a result, the blade grooves 36 are arranged at unequal pitches in the rotation direction. As shown in FIG. 4, the blade groove 36 adjacent in the rotational direction has a V-shaped partition wall 34 that is inclined forward from the substantially center in the thickness direction of the impeller 30 toward both end faces 31 in the thickness direction of the impeller 30 in the rotational direction. It is partitioned by. Further, as shown in FIG. 6, the blade groove 36 is partly divided on the radially inner side by a partition wall 35 protruding from the radially inner side of the blade groove 36 toward the radially outer side. It penetrates in the direction of the rotation axis on the outside in the radial direction. The fuel that has flowed into the blade groove 36 from the pressure-increasing passages 202 and 203 on both sides in the axial direction becomes a swirl flow 300 that rotates in opposite directions on both sides in the rotation axis direction by the partition wall 35.

  As shown in FIG. 4, at least the radially inner side of the rear surface 37 behind the blade groove 36 in the rotational direction is inclined backward in the rotational direction from the radially inner side toward the radially outer side. A line segment 110 connecting the radially inner end 37a and the radially outer end 37b of the rear surface 37 of the blade groove 36 is a straight line 104 extending radially outward from the radially inner end 37a on the radius 102 of the impeller 30. On the other hand, it is inclined backward in the rotational direction as it goes radially outward. In FIG. 4, reference numeral 100 indicates a rotating shaft of the impeller 30.

  Further, the rear surface 37 of the blade groove 36 is inclined forward in the rotational direction from the center 37 c in the thickness direction of the impeller 30 toward both end surfaces 31 in the thickness direction of the impeller 30. That is, the rear surface 37 is formed in a V shape from the center 37 c in the thickness direction of the impeller 30 toward both end surfaces 31 of the impeller 30. A line segment 112 connecting the thickness direction center 37c of the rear surface 37 and the thickness direction both ends 37d of the impeller 30 of the rear surface 37, and a straight line 106 extending forward in the rotational direction along the circumferential direction from the thickness direction center 37c. Is set in a range of 40 ° ≦ γ ≦ 60 ·. The straight line 106 is orthogonal to the central axis 100.

  As shown in FIG. 1, the fuel inlet 200 and the pressure increase passage 202 are connected by a connection passage 201. The passage area of the connection passage 201 gradually decreases from the fuel inlet 200 side toward the pressure increase passage 202. That is, the connection wall surface 21 of the connection passage 201 that connects the fuel inlet 200 and the pressure increase passage 202 gradually rises from the fuel inlet 200 toward the pressure increase passage 202 and is connected to the pressure increase passage 202. Therefore, the fuel sucked from the fuel inlet 200 is guided to the connection wall surface 21 and flows toward the blade groove 36.

  Here, the inclined straight line 108 connecting the fuel inlet side end 21a and the pressure increase passage side end 21b of the connection wall surface 21 and the fuel inlet side which is one of the thickness direction center 37c of the rear surface 37 and one end of the rear surface 37 in the thickness direction. If the angle formed by the line segment 114 passing through the end 37d and reaching the inclined straight line 108 in the forward direction of rotation is α, 90 ° ≦ α ≦ 130 ° is set.

  When 90 °> α, the fuel flow introduced into the blade groove 36 of the impeller 30 rotating at high speed and guided from the fuel inlet 200 to the connection wall surface 21 collides with the rear surface 37 of the blade groove 36 at a large angle. To do. Further, if α> 130 °, the fuel flow guided to the connecting wall surface 21 from the fuel inlet 200 and the opening of the rear surface 37 of the blade groove 36 and the rear surface 37 of the blade groove 36 becomes large. It becomes difficult to flow in. Therefore, by setting 90 ° ≦ α ≦ 130 °, the fuel smoothly flows into the blade groove 36 along the rear surface 37 of the blade groove 36 with respect to the impeller 30 rotating at high speed. As a result, as shown in FIG. 7, the pump efficiency in the pump unit 12 is improved.

Further, if the rising angle of the connecting wall surface 21 from the fuel inlet 200 toward the boosting passage 202, that is, the rising angle of the inclined straight line 108 from the fuel inlet 200 toward the boosting passage 202 is β, 10 ° ≦ β ≦ 30 ° is set. Yes.
Here, when 10 °> β, the fuel flow is separated at the corner portion of the fuel inlet 200 and the connection wall surface 21, that is, in the vicinity of the fuel inlet side end 21 a of the connection wall surface 21 when going from the fuel inlet 200 to the connection wall surface 21. And the energy of the fuel flow is reduced. Further, when β> 30 °, the passage area in the vicinity of the fuel inlet side end 21a of the connection passage 201 is increased, and the fuel flow that flows from the fuel inlet 200 to the connection wall surface 21 side stays in the direction of the pressure increase passage 202. As a result, the energy of the fuel flow is reduced. Thus, when the energy of the fuel flow is reduced, the pump efficiency is lowered. Therefore, by setting 10 ° ≦ β ≦ 30 °, it is possible to prevent the fuel flow from the fuel inlet 200 toward the connection wall surface 21 from being separated and staying. Thereby, reduction of the energy of a fuel flow can be suppressed and pump efficiency can be improved.

Further, when the aforementioned forward tilt angle γ is set in the range of γ <40 °, the direction of the swirl flow 300 that flows into the blade groove 36 is suddenly changed to the front in the rotational direction and flows out of the blade groove 36. The energy of the swirl flow 300 is reduced.
Therefore, by setting the forward tilt angle γ within the range of 40 ° ≦ γ, the energy reduction of the swirling flow 300 flowing out from the blade groove 36 is suppressed.

  Further, when the forward tilt angle γ is set in the range of γ> 60 °, the energy component that the swirling flow 300 receives from the blade groove 36 toward the front in the rotation direction when flowing out of the blade groove 36 is reduced. The pitch of the flow 300 in the rotational direction is increased. As a result, the interval between the blade grooves 36 until the swirl flow 300 flows out of the blade groove 36 and flows into the next blade groove 36 at the rear in the rotation direction becomes longer. In other words, the number of times the swirl flow 300 enters and exits the blade groove 36 while flowing through the pressure increasing passage 202 decreases, so that the fuel is not sufficiently pressurized.

  Therefore, by setting the forward tilt angle γ within the range of γ ≦ 60 °, the energy component that the swirling flow 300 receives from the blade groove 36 toward the front in the rotation direction when flowing out from the blade groove 36 increases. The pitch of the flow 300 in the rotational direction is shortened. As a result, the number of times the swirl flow 300 enters and exits the vane groove 36 while flowing through the pressure increasing passage 202 increases, so that the fuel pressure increasing efficiency is improved and the pump efficiency is improved.

  In the present embodiment, the front surface 38 in front of the blade groove 36 in the rotational direction is formed in a V shape from the center 37 c in the thickness direction of the impeller 30 toward both end surfaces 31 of the impeller 30, similarly to the rear surface 37. Has been. Thus, by making the shape of the rear surface 37 and the front surface 38 of the blade groove 36 substantially the same, the amount of fuel flowing out of the blade groove 36 and the amount of fuel flowing into the blade groove 36 are substantially equal. Become. As a result, the boosting efficiency of the fuel is improved and the pump efficiency is improved.

Further, in the present embodiment, the annular portion 32 covers the radially outer side of the blade groove 36, and no pressure increase passage is formed on the outer peripheral side of the impeller 30. As a result, the differential pressure in the rotational direction of the fuel pressure boosted in the boost passage 202 is not directly applied in the radial direction of the impeller 30, so the force applied in the radial direction to the impeller 30 is reduced. Thereby, since the rotation center of the impeller 30 can be prevented from shifting, the impeller 30 can rotate smoothly.
In this embodiment, the fuel discharge amount and fuel discharge of the fuel pump 10 can be increased by improving the pump efficiency in this way.

(Deformation)
In the present embodiment, the connection wall surface 21 is formed in a planar shape, but the connection wall surface 21 may be formed in a convex shape as shown in FIG. 8 also rises gradually from the fuel inlet 200 toward the pressure increase passage 202 and is connected to the pressure increase passage 202. Accordingly, the fuel sucked from the fuel inlet 200 is guided to the connection wall surface 21 and flows into the blade groove 36. Also in the modified embodiment, 90 ° ≦ α ≦ 130 ° is set.

(Other embodiments)
The range of the rising angle β of the inclined straight line 108, which is the rising angle of the connection wall surface 21 from the fuel inlet 200 toward the pressure increase passage 202 on the fuel inlet 200 side, is preferably 10 ° ≦ β ≦ 30 ° as in the above embodiment. The rising angle β is not limited to this angle range.
In the above-described embodiment, the rear surface 37 is inclined forward in the rotational direction from the center 37c in the thickness direction to both sides in the thickness direction within a range of 40 ° ≦ γ ≦ 60 °. Only the fuel inlet 200 side may be inclined in the range of 40 ° ≦ γ ≦ 60 ° forward in the rotational direction from the center in the thickness direction toward the fuel inlet 200 side. The range of the forward tilt angle γ is preferably 40 ° ≦ γ ≦ 60 °, but the forward tilt angle γ is not limited to this angle range.

  In the above embodiment, the pressure of the fuel is increased by the pressure increasing passages 202 and 203 on both sides of the impeller 30 in the thickness direction, and the fuel sucked from the fuel inlet 200 on one side in the thickness direction across the impeller 30 is supplied to the motor on the other side in the thickness direction. It pumped in the part 13. On the other hand, for example, if the pressurized fuel is not pumped into the motor unit 13, the booster passage 203 on the side opposite to the fuel inlet 200 in the thickness direction is not provided with respect to the impeller, and only the booster passage 202 on the fuel inlet 200 side is provided. The fuel may be boosted.

Moreover, in the said embodiment, although the connection wall surface 21 was formed in planar shape or convex shape, you may form the connection wall surface 21 in concave shape.
Moreover, in the said embodiment, although the radial direction outer side of the blade groove | channel 36 was covered with the annular part 32 (refer FIG. 5), you may open | release the radial direction outer side of the blade groove | channel 36 without providing the annular part 32 in this invention. . Moreover, in the said embodiment, although the shape of the front surface 38 ahead of the rotation direction of the blade groove 36 was made into the V shape which match | combined with the shape of the rear surface 37, let the front surface of the blade groove 36 be a plane along a thickness direction. Also good.
In the above embodiments, the motor unit of the fuel pump is a brush motor, but the motor unit may be a brushless motor.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

Sectional drawing of the impeller and pump case in the II line position of FIG. 3 (B). Sectional drawing which shows the fuel pump of this embodiment. (A) is explanatory drawing which shows the pump case on the discharge side, (B) is explanatory drawing which shows the pump case on the suction side. (A) is the schematic diagram which looked at the blade groove | channel of the impeller from the fuel suction side, (B) is the BB sectional drawing of (A). (A) is the whole view which looked at the impeller from the fuel suction side, (B) is an enlarged view of the blade groove part of (A). The enlarged view of the pressure | voltage rise passage shown in FIG. The characteristic view which shows the relationship between angle (alpha) and pump efficiency. Sectional drawing of the deformation | transformation form in the same position as FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Fuel pump, 12: Pump part, 13: Motor part, 20, 22: Pump case (case member), 21: Connection wall surface, 30: Impeller, 31: End surface, 34: Partition, 36: Blade groove, 37: Rear surface, 37a: radially inner end, 37b: radially outer end, 37c: thickness direction center, 37d: thickness direction both ends (fuel inlet side end), 100: rotating shaft, 102: radius, 104, 106: straight line 108: Inclined straight line, 110, 112, 114: Line segment, 200: Fuel inlet, 201: Connection passage, 202, 203: Boost passage

Claims (4)

An impeller that is rotated by the rotational driving force of the motor unit, has a plurality of blade grooves provided in the rotation direction, and pressurizes the fuel sucked into the pressure increasing passage formed along the blade grooves from the fuel inlet;
A case member that rotatably accommodates the impeller and forms the fuel inlet and the pressure increasing passage;
With
At least the fuel inlet side in the thickness direction of the impeller on the rear surface behind the rotation direction of the blade groove is inclined forward in the rotation direction from the center in the thickness direction toward the fuel inlet side in the thickness direction, At least the radially inner side of the rear surface is inclined rearward in the rotational direction from the radially inner side toward the radially outer side, and with respect to a straight line extending radially outward from the radially inner end of the rear surface on the radius of the impeller, A line segment connecting the radially inner end and the radially outer end of the rear surface is inclined rearward in the rotational direction as it goes radially outward.
A connecting wall surface of the case member connecting the fuel inlet and the boosting passage rises gradually from the fuel inlet toward the boosting passage and is connected to the boosting passage, and the fuel inlet side of the connecting wall surface An inclined straight line connecting the end and the pressure increasing passage side end and a line segment that reaches the inclined straight line from the center in the thickness direction of the rear surface through the fuel inlet side end of the rear surface are formed forward in the rotational direction. A fuel pump in which 90 ° ≦ α ≦ 130 °, where α is an angle.   The fuel pump according to claim 1, wherein the rear surface is inclined forward in the rotational direction from the center in the thickness direction toward both sides in the thickness direction.   3. The fuel pump according to claim 1, wherein a rising angle of the inclined straight line from the fuel inlet side end toward the boost passage side end is β, 10 ° ≦ β ≦ 30 °. A line segment connecting the center in the thickness direction and the end in the thickness direction on the inclined surface inclined forward in the rotational direction from the center in the thickness direction of the rear surface toward the end in the thickness direction. The angle formed by a straight line extending forward in the rotational direction along the circumferential direction from the center in the thickness direction is 40 ° ≦ γ ≦ 60 °, according to any one of claims 1 to 3. Fuel pump.

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