TWI464321B - Fuel pump - Google Patents

Description

Fuel pump

The present invention relates to a fuel pump, and more particularly to a fuel pump having an impeller and a pump casing that rotatably receives the impeller.

A fuel pump is known as a device for supplying fuel in a fuel tank to an internal combustion engine such as an engine of an automobile. In this fuel pump, there is usually a pump portion. The pump unit includes a housing and a substantially disk-shaped impeller rotatably housed in the housing. An annular fin groove portion is formed along the outer peripheral portion of the impeller on a surface facing the fuel suction side of the impeller. A fin groove portion is formed at a position corresponding to the fin groove portion formed on the suction side with respect to the fuel delivery side of the impeller. The fin groove formed on the suction side surface of the impeller and the delivery side surface communicate with each other at the bottom.

A pump passage is formed in each of the inner surfaces of the housing facing the suction side surface and the delivery side surface of the impeller, and the pump passage extends from the upstream end in a direction opposite to the rotation direction of the impeller in a region opposed to the fin groove portion formed in the impeller Until the downstream end. The upstream end of the pump passage on the suction side communicates with the outside of the casing through the fuel suction port, and the downstream end of the pump passage on the delivery side communicates with the outside of the casing through the fuel delivery port.

In the fuel pump constructed as described above, when the impeller rotates, fuel is sucked into the pump casing from the suction port, and the sucked fuel is introduced into the fin groove portion of the impeller and the pump passage. The fuel sucked into the pump casing acts on a centrifugal force resulting from the rotation of the impeller. The fuel sucked into the pump casing is pressurized by the centrifugal force of the impeller, flows to the downstream side along the pump passage, and is sent out from the delivery port to the outside of the pump casing.

In such a fuel pump, in order to prevent a gap between a surface of an impeller and a pump cover that contacts the impeller surface and a sliding surface of a pump base, a pump discharge efficiency due to leakage loss occurs. The reduction is made, and the gap in the thrust direction is set to be extremely small. Therefore, when the fuel pressure in the pump chamber rises from the fuel suction port toward the pump chamber outlet by the rotation of the fin groove, the impeller is located near the pump chamber outlet of the pump casing and near the fuel suction port of the pump casing. The pressure between the two is unbalanced, and it is rotated while being in contact with the pump housing at a position opposite to the pump chamber outlet.

Therefore, in order to prevent such contact, it is known that a gap larger than a small gap between the surface of the impeller and the pump casing is formed in the vicinity of the pump outlet of the sliding surface of the pump casing to form a relief portion (see, for example, Patent Document 1).

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Patent Laid-Open No. 5-187832

According to experiments and verifications conducted by the inventors, it was confirmed that the dimensional deformation of the impeller was remarkably present in the concave portion group. Therefore, in order to prevent contact between the pump casing and the impeller, it is difficult to refer to the relief portion shown in Patent Document 1 as a perfect solution.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a simple and inexpensive configuration to prevent an increase in rotational resistance of an impeller and/or a failure of a lock of a pump chamber, and the like. A fuel pump that ensures reliability and maintains pump performance.

The fuel pump of the present invention includes a disk-shaped impeller, a casing formed by a pump cover and a pump body that rotatably accommodates the impeller, and a fuel pump that rotationally drives the motor portion of the impeller, and the impeller is The front and back sides of the front and back are formed in a region extending from the outer circumference toward the inner side by a predetermined distance in the circumferential direction, and a plurality of concave recess groups are formed in the circumferential direction, and the pump cover facing the impeller surface is formed to face each other. a first groove extending from the upstream end to the downstream end in a region of the concave portion of the impeller, and a pump body opposed to the impeller back surface is formed to extend from a upstream end to a region of the concave portion of the impeller a second groove up to the downstream end, wherein the casing is formed with a fuel delivery port and a fuel suction port; the fuel delivery port communicates with the vicinity of the downstream end of the first groove and the outside of the casing, and the fuel suction port is Connecting the vicinity of the upstream end of the second groove and the outside of the casing; viewed in the direction of rotation of the impeller, between the upstream end and the downstream end of the first groove of the pump casing, and the pump main Between the upstream end and the downstream end, a sealing portion is provided, and the fuel pump is formed at a position facing the concave portion of the impeller at a sealing portion of at least one of the casings to form an expansion of the concave portion of the impeller. The concave shape of the micron order.

According to the fuel pump of the present invention, it is possible to obtain a simple and inexpensive configuration, prevent the occurrence of malfunctions such as an increase in the rotational resistance of the impeller and/or the lock of the pump chamber, and a fuel which ensures reliability and maintains pump performance. Pump.

The above and other objects, features, and advantages of the present invention will be apparent from the description and appended claims.

Embodiment 1.

Embodiment 1 of the present invention will be described with reference to Figs. 1 to 6 .

In addition, in the drawings, the same symbols represent the same or equal parts. The feature of the present invention is characterized in that a seal portion from the fuel delivery port to the fuel suction port is formed on the sliding surface of the inner surface of the housing of the impeller blade groove group as viewed from the direction of rotation of the impeller. A person who enlarges the concave shape on the substantially circumference of the clearance in a more microscopic manner.

1 is a longitudinal cross-sectional view showing the overall configuration of a fuel pump according to Embodiment 1 of the present invention. As shown in FIG. 1, the fuel pump 10 is composed of 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, and a rotor 76. The outer casing 72 is formed in a substantially cylindrical shape. The motor cover 73 is fixed to the outer casing 72 by caulking the upper end 72a of the outer casing 72 (the upper and lower sides of the first pump as the upper and lower sides of the fuel pump 10). The motor cover 73 is formed with a delivery port 73a that opens upward. The magnets 74, 75 are fixed to the inner wall of the outer casing 72. The rotor 76 has a body 77 and a shaft 78. The body 77 is formed of a laminated core, a coil, or the like, and the shaft 78 is inserted through the body 77 up and down. The upper end portion 78a of the shaft 78 is rotatably attached to the motor cover 73 via a bearing 81. The lower end portion 78b of the shaft 78 is rotatably attached to the pump cover 14 of the pump portion 12 through the bearing 82. Here, the motor unit 70 has the same configuration as the conventional fuel pump, and thus a detailed description thereof will be omitted.

Fig. 2 is an enlarged view showing the pump unit 12 of Fig. 1 selected and extracted.

The pump unit 12 includes a housing 18 and an impeller 20 .

As shown in Fig. 3, the impeller 20 has a substantially disk shape. On the surface on the fuel suction side of the impeller 20, a first fin groove group 20b continuous in the circumferential direction is formed in an annular shape with a predetermined distance from the outer peripheral surface 20e. That is, the first fin groove group 20b is separated from the outer peripheral surface 20e of the impeller 20 by the outer peripheral wall 20d of the impeller 20. The surface of the impeller 20 on the fuel supply side is in a ring-like manner at a position corresponding to the first fin groove group 20b formed on the suction side surface of the impeller 20 (that is, a region separated by a predetermined distance from the outer peripheral surface 20e). The second fin groove group 20c continuous in the circumferential direction is formed. Further, the bottom of the first fin group 20b and the bottom of the second fin group 20c are communicated by a communication hole (not shown). In the center portion of the impeller 20, an engagement hole 20a having a substantially D-shaped cross section in a direction perpendicular to the axis penetrating in the thickness direction is formed. A shaft 78 is engaged with the engaging hole 20a. When the turns of the rotor 77 are energized, the shaft 78 will rotate, whereby the impeller 20 will rotate.

The casing 18 is a combination of the pump cover 14 and the pump body 16. As shown in Figs. 2 and 5, a concave portion 14a which is circular in plan view is formed on the surface of the impeller side of the pump cover 14 (i.e., the lower surface of Fig. 1). The diameter of the recess 14a is substantially the same as the diameter of the impeller 20, and the depth of the recess 14a is substantially the same as the thickness of the impeller 20.

The impeller 20 is rotatably fitted in the recess 14a.

In the bottom surface of the recessed portion 14a of the pump cover 14 (hereinafter referred to as "the lower surface of the pump cover"), a groove extending in the circumferential direction with respect to the region facing the second blade groove group 20c of the impeller 20 is formed. The second pump passage 31 is in the form of a second pump passage 31. The upstream end 31a of the second pump passage 31 is formed in the vicinity of a position facing the upstream end 30a of the first pump passage 30 to be described later.

A fuel delivery port 41 is formed at the downstream end 31b of the second pump passage 31. The fuel delivery port 41 extends from the second pump passage 31 to the upper surface of the pump cover 14 (the upper surface of FIG. 1), and communicates with the second pump passage 31 and the outside of the casing 18 (in detail, the inside of the casing 72) ).

Between the impeller 20 and the recess 14a of the pump cover 14, a slight gap A in the axial direction shown in Fig. 6 is formed, and between the impeller 20 and the inner peripheral surface 14b of the recess 14a of the pump cover 14 is formed. 6 shows a slight gap B in the diameter direction. These gaps A and B are provided to smoothly rotate the impeller 20 .

Further, in the drawing, although the gap between the impeller 20 and the pump cover 14 is schematically shown to be wide, it is actually about several μm to several tens of μm.

A groove-shaped first pump passage 30 that extends in a circumferential direction with respect to a region facing the first fin groove group 20b of the impeller 20 is formed on the upper surface of the pump body 16. A fuel suction port 40 is provided at the upstream end 30a of the first pump passage 30. Between the upstream end 30a and the downstream end 30b of the first pump passage 30, a vapor (Vapor) discharge port 30c that penetrates the pump body 16 toward the upper and lower sides (above and below the first drawing) is provided. A recess 16b is formed in a central portion of the pump body 16, and a thrust bearing 33 concentrically with the shaft 78 is disposed in the recess 16b.

The thrust bearing 33 is subjected to the thrust load of the rotor 76.

The casing 18 composed of the pump cover 14 and the pump body 16 is fixed to the outer casing 72 by caulking the lower end 72b of the outer casing 72 in a state in which the impeller 20 is assembled to the recess 14a of the pump cover 14.

Further, in a state in which the casing 18 is fixed to the casing 72, the lower end portion 78b of the shaft 78 is fitted to the engaging hole 20a of the impeller 20 at a position lower than a portion supported by the bearing 82. A thrust bearing 33 is interposed between the lower end of the shaft 78 and the pump body 16.

In the fuel pump 10 configured as described above, when the current flows in the rotor 76 and the impeller 20 rotates, the fuel in the fuel tank (not shown) is sucked into the casing 18 through the fuel suction port 40. The fuel sucked into the casing 18 first flows into the upstream end 30a of the first pump passage 30. As shown in Fig. 6, the fuel flowing into the first pump passage 30 is swirled by the vortex S between the first pump passage 30 and the first fin groove group 20b by the rotation of the impeller 20. Further, the fuel system that has flowed into the first pump passage 30 is pressurized by the rotation of the impeller 20, and flows from the upstream end 30a toward the downstream end 30b to the first pump passage 30. Then, the fuel sent to the motor unit 70 by the fuel delivery port 41 formed at the downstream end of the second pump passage 31 flows into the motor unit 70, and is sent to the fuel pump 10 from the delivery port 73a formed in the motor cover 73. external.

The slight gap A in the axial direction shown in the sixth drawing described above is one of the important factors for greatly improving the feeding performance of the fuel pump 10. In other words, if the gap is enlarged, the smooth flow of the eddy current S is hindered, and the leakage loss in the casing 18 is increased, and as a result, the amount of fuel sent from the fuel delivery port 41 is lowered. In other words, maintaining and controlling the gap as small as possible is an extremely important issue in maintaining the pumping performance. On the other hand, it is known that the impeller 20 is formed of a resin material such as thermosetting or thermoplasticity. However, since the impeller 20 is normally used in a state of being immersed in a fuel, the water is absorbed by the water. And cause dimensional changes (expansion). When the amount of expansion caused by moisture absorption is close to the gap A disposed in the axial direction, the rotation of the impeller and the casing hinders the rotational motion, thereby increasing the rotational wear resistance, thereby causing a decrease in the delivery efficiency of the fuel pump, and further in the impeller 20 When the expansion exceeds the set gap A, there are even concerns about the lockup of the pump chamber in the most severe cases. According to the foregoing background, the gap must be set to a small extent after the expansion of the impeller due to fuel impregnation, and the degree of the control is not blocked.

In the form of the outer wheel portion 20g shown in Fig. 3, particularly in the impeller 20 of the thermosetting resin, the amount of expansion of the wing portion 20f is higher than that of the other portions (the flat portion and the outer peripheral portion 20e). Characteristics. In the first embodiment, focusing on the above-described features, a concave shape having an estimated amount of expansion is provided in advance in the casing 18 so as to face the impeller fin portion 20f on the sliding surface.

Specifically, the pump passages 30 and 31 are provided on the sliding surfaces of the pump body 16 and the pump cover 14 in substantially C-shape, and are oriented in a direction extending in the circumferential direction, in other words, in the direction The sealing portion between the upstream end 30a and the downstream end 30b of the pump passages 30, 31 and the upstream end 31a and the downstream end 31b is provided with a concave shape 35, 36 which is estimated to be slightly expanded by the amount of expansion of the impeller 20, and is subjected to a portion The expansion of the gap.

According to the fuel pump of the first embodiment of the present invention configured as described above, when the flap portion 20f is expanded, it is possible to prevent the rotation resistance of the impeller 20 from increasing or the failure of the pump chamber to be blocked. At the same time, since only the area where the gap is enlarged is limited to the necessary area, the pumping performance is not greatly reduced, in other words, the reliability can be ensured and the pump performance can be maintained.

Further, in the above description, the concave shapes 35 and 36 formed on the inner surface of the casing 18 have been described as being formed in the pump main body 16 and the pump cover 14, respectively, but only one of them may be formed.

Further, as shown in Fig. 6, as shown in Fig. 6, even if the concave shapes 50a and 50b having the estimated expansion amount are provided on the impeller side, the same effect can be expected.

Further, in the fuel pump 10 according to the first embodiment, since the pump body 16 and the pump cover 14 or the impeller 20 are formed in a concave shape, the other parts are those in which the conventional configuration (member) can be used.

The specific examples of the present invention have been described in detail using the first embodiment, but these are merely examples and are not intended to limit the scope of the patent application. The technique described in the patent application scope includes various modifications and changes to the specific examples exemplified above.

In addition, the technical elements described in the present specification or the drawings are technically useful by being used alone or in various combinations, and are not limited to the combination described in the claims at the time of filing a patent. Furthermore, the techniques exemplified in the specification or the drawings are those in which a plurality of persons are simultaneously achieved, and are technically useful for achieving the purpose of one of them.

(industrial availability)

The present invention is suitable as a fuel pump for supplying fuel in a fuel tank to an internal combustion engine such as an engine of an automobile.

10. . . Fuel pump

12. . . Pump department

14. . . Pump cover

14a, 16b. . . Concave

14b. . . Inner circumference

16. . . Pump body

18. . . case

20. . . impeller

20a. . . Engagement hole

20b. . . First wing groove group (concave group)

20c. . . Second wing groove group (concave group)

20d. . . Peripheral wall

20e. . . Peripheral surface

20f. . . Wing

20g. . . Outer wheel

30. . . First pump path

31. . . Second pump path

30a. . . The upstream end of the first pump passage 30

30b. . . The downstream end of the first pump passage 30

30c. . . Vapor discharge

31a. . . The upstream end of the second pump passage 31

31b. . . The downstream end of the second pump passage 31

33. . . Thrust bearings

35. . . Concave shape (pump main body side)

36. . . Concave shape (pump cover side)

40. . . Fuel intake

41. . . Fuel delivery

50a, 50b. . . Concave shape (impeller side)

70. . . Motor department

72. . . shell

72a. . . Upper end

72b. . . Lower end

73. . . Motor cover

73a. . . Send out

74, 75. . . magnet

76. . . Rotor

77. . . Ontology

78. . . axis

78a. . . Upper end

78b. . . Lower end

81, 82. . . Bearing

A. . . Axial direction clearance

B. . . Diameter clearance

S. . . vortex

Fig. 1 is a longitudinal sectional view showing the overall configuration of a fuel pump according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view showing the pump unit of Fig. 1 in an enlarged manner.

Fig. 3 is a plan view of the impeller in the first embodiment of the present invention.

Fig. 4 is a plan view of the pump body according to the first embodiment of the present invention as seen from the impeller side.

Fig. 5 is a plan view of the pump cover in the first embodiment of the present invention as seen from the impeller side.

Fig. 6 is a partial cross-sectional view showing the pump unit 12 in the first embodiment of the present invention.

12. . . Pump department

14. . . Pump cover

14a, 16b. . . Concave

14b. . . Inner circumference

16. . . Pump body

18. . . case

20. . . impeller

20a. . . Engagement hole

20b. . . First wing groove group (concave group)

20c. . . Second wing groove group (concave group)

20d. . . Peripheral wall

20e. . . Peripheral surface

30. . . First pump path

31. . . Second pump path

33. . . Thrust bearings

40. . . Fuel intake

41. . . Fuel delivery

72b. . . Lower end

78. . . axis

78b. . . Lower end

82. . . Bearing

Claims (4)

A fuel pump (10) includes a disk-shaped impeller (20), a casing (18) composed of a pump cover (14) and a pump body (16) that rotatably accommodates the impeller, and a rotary drive The motor portion (70) of the impeller is formed in a region extending from the outer circumference toward the inner side by a predetermined distance in the circumferential direction on the front and back surfaces of the impeller (20), and forms a recessed concave portion (20b, respectively) in the circumferential direction. 20c), the pump cover (14) facing the impeller surface is formed with a region extending from the upstream end (31a) to the downstream end (31b) of the recess portion (20c) facing the impeller a groove (31), wherein a pump body (16) facing the back surface of the impeller is formed with a region extending toward the concave portion group (20b) of the impeller from an upstream end (30a) to a downstream end (30b) In the second groove (30), a fuel delivery port (41) and a fuel suction port (40) are formed in the casing (18), and the fuel delivery port (41) communicates with the first groove (31). The vicinity of the downstream end (31b) is external to the casing (18), and the fuel suction port (40) communicates with the vicinity of the upstream end (30a) of the second groove (30) and the outside of the casing (18). Viewed in the direction of rotation of the impeller, between the upstream end and the downstream end of the first groove (31) of the pump casing (14), and the upstream and downstream ends of the second groove (30) of the pump body (16) Between the ends, a sealing portion is provided, and the fuel pump is formed at a position facing the concave portion group (20b, 20c) of at least one of the sealing portions of the casing (18). The micro-level concave shape (35, 36) of the expansion amount of the concave portion group (20b, 20c) of the impeller (20) is measured, and when the concave portion group (20b, 20c) of the impeller (20) is expanded, the impeller (20) is also prevented. The rotation resistance increases. The fuel pump according to claim 1, wherein the concave shape (35, 36) is formed in both the pump cover (14) and the pump body (16). The fuel pump according to claim 1, wherein the shape of the concave portion (20b, 20c) of the impeller (20) is a concave shape (50a, 50b) for predicting the amount of expansion of the concave portion of the impeller. ). A fuel pump (10) includes a disk-shaped impeller (20), a casing (18) composed of a pump cover (14) and a pump body (16) that rotatably accommodates the impeller, and a rotary drive The motor portion (70) of the impeller is formed in a region extending from the outer circumference toward the inner side by a predetermined distance in the circumferential direction on the front and back surfaces of the impeller (20), and forms a recessed concave portion (20b, respectively) in the circumferential direction. 20c), the pump cover (14) facing the impeller surface is formed with a region extending from the upstream end (31a) to the downstream end (31b) of the recess portion (20c) facing the impeller In the first groove (31), the pump body (16) facing the back surface of the impeller is formed such that a region facing the concave portion group (20b) of the impeller extends from the upstream end (30a) to the downstream end (30b). In the second groove (30), a fuel delivery port (41) and a fuel suction port (40) are formed in the casing (18), and the fuel delivery port (41) communicates with the downstream of the first groove (31). The end (31b) is adjacent to the outside of the aforementioned casing (18), and the fuel is sucked The inlet (40) communicates with the vicinity of the upstream end (30a) of the second groove (30) and the outside of the casing (18), and is viewed in the direction of rotation of the impeller, and the first groove (31) of the pump cover (14) Between the upstream end and the downstream end, and between the upstream end and the downstream end of the second groove (30) of the pump body (16), respectively, a sealing portion is provided, and the fuel pump places the impeller (20) The shape of the concave group (20b, 20c) is a concave shape (50a, 50b) for predicting the amount of expansion of the concave portion of the impeller, and when the concave portion (20b, 20c) of the impeller (20) is expanded, the impeller is also prevented ( 20) The rotation resistance increases.