Fuel pump

Abstract

To improve the radiation efficiency of heat generated by an armature while suppressing the rotational resistance of the armature of a motor.SOLUTION: A fuel pump sucks a fuel from a fuel suction port and discharges the pressurized fuel from a fuel discharge port. The fuel pump has a pump unit that increases the pressure of the fuel suctioned in from the fuel suction port and discharges the fuel from the pump discharge port, a motor unit that is a drive source for the pump unit, and is provided with an armature constituting a rotor, and a housing part that coaxially houses the pump unit and the motor unit and is configured to allow the fuel discharged from the pump discharge port to pass around the armature of the motor unit and to be discharged from a fuel discharge port. One end side in the axial direction of the armature, which faces the pump unit, is covered by a cover member 50. Recessed-protruding shapes 55r, 55e, 54d, 54u are formed on at least one of the front surface side and the rear surface side of the cover member 50.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present technology relates to a fuel pump that draws fuel from a fuel tank through a fuel suction port, discharges the pressurized fuel from a fuel discharge port, and supplies it to an internal combustion engine. [Background technology]

[0002] Patent Document 1 discloses a technology related to the above-mentioned fuel pump. The fuel pump disclosed in Patent Document 1 is a pump that pumps fuel in a fuel tank to an internal combustion engine. The fuel pump includes a pump unit (not shown) and a motor unit 100 that is a drive source for the pump unit. As shown in FIG. 7, the motor unit 100 has an armature 102 that forms a rotor. The pump unit and the motor unit 100 are housed coaxially in a cylindrical housing unit (not shown). The housing unit is configured so that fuel discharged from the pump unit passes around the armature 102 of the motor unit 100 and is discharged from a fuel discharge port (not shown).

[0003] As shown in Fig. 7, one axial end (lower end) of the armature 102 of the motor unit 100 facing the pump unit is covered by a metal cover member 104. This prevents fuel discharged from the discharge port of the pump unit from directly hitting the lower end side of the armature 102, and allows the cover member 104 to smoothly guide the fuel around the armature 102. Furthermore, since the lower end side of the armature 102 is covered by the cover member, the lower end side of the armature 102 becomes flat, thereby reducing the rotational resistance of the armature 102. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4158154 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above fuel pump, the lower end side of the armature 102 is covered with a cover member so as to be flat, thereby reducing the rotational resistance of the armature 102. For this reason, even if the cover member is made of metal, the heat dissipation efficiency of the armature 102 cannot be increased significantly because the cover member is flat.

[0006] The present technology has been made to solve the above-mentioned problems, and the problem that the present invention aims to solve is to improve the heat dissipation efficiency of the heat generated by the armature of a motor while suppressing the rotational resistance of the armature. [Means for solving the problem]

[0007] The above-mentioned problems can be solved by various technologies. A first technology is a fuel pump that draws fuel from a fuel tank through a fuel suction port and discharges the pressurized fuel from a fuel discharge port to supply it to an internal combustion engine, the fuel pump including: a pump unit that pressurizes the fuel drawn through the fuel suction port and discharges it from a pump discharge port; a motor unit that is a drive source for the pump unit and has an armature that forms a rotor; and a housing unit that coaxially houses the pump unit and the motor unit and is configured to allow the fuel discharged from the pump discharge port to pass around the armature of the motor unit and be discharged from the fuel discharge port, wherein one axial end side of the armature that faces the pump unit is covered by a cover member, and the cover member has an uneven shape formed on at least one of its front and back sides.

[0008] According to the first technology, one axial end of the armature facing the pump section is covered with a cover member. Therefore, the cover member prevents fuel discharged from the pump discharge port from directly hitting the one axial end of the armature, and the fuel is smoothly guided around the armature. Also, by covering the one axial end of the armature with the cover member, that portion becomes relatively flat, thereby reducing the rotational resistance of the armature. Furthermore, the cover member has an uneven shape on at least one of its front and back sides. Therefore, the uneven shape can expand the surface area of ​​the cover member, improving the efficiency of heat dissipation generated by the armature.

[0009] According to the second technique, the concave-convex shape of the cover member is formed on both the front and back sides, and the height difference of the concave-convex shape on the back side is set to a value larger than the height difference of the concave-convex shape on the front side. In other words, the height difference of the concave-convex shape on the front side of the cover member, which directly hits the fuel discharged from the pump discharge port, is smaller than the height difference of the concave-convex shape on the back side, so the rotational resistance of the armature does not become very large.

[0010] According to a third technique, on a predetermined surface on which the concave-convex shape of the cover member is formed, the height difference of the concave-convex shape on the radially inner side is set to a value larger than the height difference of the concave-convex shape on the radially outer side. In other words, the height difference of the concave-convex shape on the radially outer side, where the rotation speed is higher during rotation of the armature, is smaller than the height difference of the concave-convex shape on the radially inner side, where the rotation speed is lower, so that the rotational resistance of the armature does not increase significantly.

[0011] According to a fourth technique, the concave and convex shape of the cover member is a plurality of radially arranged ridges, which improves fuel agitation during rotation of the armature and improves heat dissipation efficiency.

[0012] According to a fifth technology, the ridges are curved so as to be convex in the direction of rotation of the armature, which makes it easier for fuel to flow from the center to the outside in the radial direction, further improving heat dissipation efficiency.

[0013] According to a sixth technology, the cover member includes a cover body that covers one axial end of the armature and a terminal that is connected to the coil of the armature, and the cover body and the terminal are integrally formed from the same metal. This allows heat from the armature to be guided to the cover member (cover body) via the terminal, enabling efficient heat dissipation. [Effects of the Invention]

[0014] According to the technology of the present application, it is possible to improve the efficiency of dissipating heat generated by the armature of a motor while suppressing the rotational resistance of the armature. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a vertical cross-sectional view showing a fuel pump according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic plan view showing a pump portion of the fuel pump. [Figure 3] FIG. 2 is a vertical cross-sectional view showing a rotor (armature) of a motor portion of the fuel pump. [Figure 4] FIG. 4 is a perspective view of a cover member that covers a lower end surface of the armature. [Figure 5] 5 is a vertical cross-sectional view of the cover member (a cross-sectional view taken along the arrows VV in FIG. 4). [Figure 6] FIG. 10 is a plan view illustrating a modified example of the cover member. [Figure 7] FIG. 10 is a perspective view showing an armature and a cover member of a conventional fuel pump. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Embodiment 1] A fuel pump 10 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 6. The fuel pump 10 according to this embodiment is a pump device that draws fuel from a fuel tank (not shown) through a fuel suction port 252e and discharges the pressurized fuel from a fuel discharge port 23p to supply it to a vehicle engine (not shown). Here, front, rear, left, right, and up and down in the figures correspond to front, rear, left, right, and up and down of the fuel pump 10.

[0017] <Outline of the fuel pump 10> 1, fuel pump 10 includes a pump section 30 that pressurizes fuel, a motor section 40 that rotationally drives pump section 30, a fuel suction port 252e, a fuel discharge port 23p, and a housing section 20 that houses pump section 30 and motor section 40 coaxially. Housing section 20 is made up of a cylindrical housing main body 21, an upper lid section 23 that closes the upper end side of housing main body 21, and a pump case section 25 that is a lower lid section that closes the lower end side of housing main body 21.

[0018] 1, a fuel discharge port 23p that communicates with the internal space of the housing main body 21 is formed in the center of the top lid portion 23 of the housing portion 20. Also provided in the center of the top lid portion 23 is an upper bearing portion 23j that supports the upper end of the rotation center shaft 13 of the pump portion 30 and the motor portion 40. Furthermore, the top lid portion 23 of the housing portion 20 is provided with a connector 23c to which a power cable (not shown) that supplies power to the motor portion 40 is connected, and a pressure adjustment valve 23v that adjusts the pressure of the fuel discharged from the fuel discharge port 23p.

[0019] As shown in FIG. 1, the pump case 25, which is the lower cover of the housing 20, is a component of the pump section 30. As shown in FIGS. 1 and 2, the pump section 30 includes an upper case 251 constituting the upper side of the pump case 25, a lower case 252 constituting the lower side of the pump case 25, and a disc-shaped impeller 32 that rotates within the pump flow path of the pump case 25. The impeller 32 is configured to receive the rotational force of the rotation center shaft 13 and rotate integrally with the rotation center shaft 13. As shown in FIG. 1, the upper case 251 of the pump case 25 is provided with a lower bearing 251j that supports the lower end of the rotation center shaft 13. As shown in FIG. 2, the upper case 251 is formed with a pump discharge port 251p that communicates with the pump flow path. As shown in FIGS. 1 and 2, the lower case 252 of the pump case 25 is formed with a fuel suction port 252e that draws fuel and directs it to the pump flow path.

[0020] <Regarding the motor unit 40> The motor unit 40 is a DC motor. As shown in Fig. 1, the motor unit 40 is composed of a plurality of pairs of planar arc-shaped permanent magnets 41 fixed to the inner wall surface of the housing main body 21 of the housing unit 20, and a rotor 43 that is fixed coaxially to the rotation center axis 13 and rotates around the axis radially inside the permanent magnets 41. As shown in Fig. 3, the rotor 43 is composed of an armature 430, a commutator 45 (segments) provided on the upper end side of the armature 430, and a cover member 50 that covers the lower end side of the armature 430.

[0021] As shown in Fig. 3, the armature 430 is composed of coil cores 431 with multiple poles arranged at equal intervals in the circumferential direction, resin coil bobbins 433, and coils 435 wound around each coil core 431 via the coil bobbins 433. The commutator 45 supplies power supplied from the connector 23c to each coil 435 of the armature 430 in sequence via brushes (not shown) and segments of the commutator 45. The cover member 50 covers the lower end side of the armature 430, thereby preventing fuel discharged from the pump discharge port 251p of the pump unit 30 from directly hitting the lower end side of the armature 430, i.e., the unevenness of the coil bobbins 433 of the armature 430 or the connection terminals of the coils 435. This allows the cover member 50 to smoothly guide the fuel discharged from the pump unit 30 around the armature 430. Furthermore, by covering the lower end side of the armature 430 with the cover member 50, this portion becomes relatively flat, thereby reducing the rotational resistance of the armature 430.

[0022] <Specific configuration of the cover member 50> The cover member 50 is a press-molded product made of metal such as aluminum, and includes a cover main body 50m and a terminal portion 51 connected to the coil 435 of the armature 430, as shown in FIGS. 4 and 5. The cover main body 50m of the cover member 50 is composed of a ring-shaped bottom plate 52, a truncated cone-shaped mountain portion 54 provided radially inward of the bottom plate 52, and a fence-like vertical wall portion 55 provided upright along the outer periphery of the bottom plate 52. As shown in FIG. 1, the mountain portion 54 of the cover member 50 is formed in a truncated cone shape to avoid interference with the lower bearing portion 251j of the pump unit 30 (upper case 251), which protrudes upward. A circular opening 57 is formed in the center of the mountain portion 54, through which the rotation center shaft 13 passes.

[0023] 3 and 4, a plurality of terminal portions 51 are provided in the circumferential direction on the vertical wall portion 55 of the cover member 50 at positions corresponding to the connection terminals of the coils 435 of the armature 430. Furthermore, as shown in Fig. 4, a plurality of engaging claw portions 58 are provided in the circumferential direction on the vertical wall portion 55 of the cover member 50 at positions corresponding to the claw receiving portions (not shown) of the coil bobbin 433 of the armature 430. That is, the terminal portions 51 of the cover member 50 are connected to the connection terminals of the coils 435 of the armature 430, and further, the engaging claw portions 58 of the cover member 50 engage with the claw receiving portions of the coil bobbin 433 of the armature 430, whereby the cover member 50 is fixed to the armature 430 while covering the lower end portion of the armature 430.

[0024] 4, a first uneven shape 55r is formed around the entire periphery on the outer circumferential surface (front surface side) of the vertical wall portion 55 of the cover member 50 in consideration of heat dissipation, and a second uneven shape 55e is formed around the entire periphery on the inner circumferential surface (back surface side) of the vertical wall portion 55 in consideration of heat dissipation. Also, a third uneven shape 54d is formed around the entire periphery on the lower surface side (front surface side) of the mountain-shaped portion 54 of the cover member 50, and a fourth uneven shape 54u is formed around the entire periphery on the upper surface side (back surface side) of the mountain-shaped portion 54. Here, the unevenness height difference between the second uneven shape 55e and the fourth uneven shape 54u on the back surface side of the cover member 50 is set to a value greater than the unevenness height difference between the first uneven shape 55r and the third uneven shape 54d on the front surface side. That is, the unevenness 55r, 54d on the surface side of the cover member 50, which comes into direct contact with the fuel discharged from the pump discharge port 251p of the pump section 30 and comes into contact with the flowing fuel, has a relatively small height difference dimension, so the rotational resistance of the armature 430 does not become very large.

[0025] Furthermore, on the rear surface side of the cover member 50, the height difference of the second uneven shape 55e is set to a value smaller than the height difference of the fourth uneven shape 54u. Furthermore, on the front surface side of the cover member 50, the height difference of the first uneven shape 55r is set to a value smaller than the height difference of the third uneven shape 54d. In this way, by making the height difference of the uneven shapes 55r and 55e on the radially outer side, where the rotation speed is higher during rotation of the armature 430, smaller than the height difference of the uneven shapes 54d and 54u on the radially inner side, where the rotation speed is lower, the rotational resistance of the armature 430 does not increase significantly. In this embodiment, the height difference of the first uneven shape 55r, the second uneven shape 55e, the third uneven shape 54d, and the fourth uneven shape 54u can each be set to approximately 1 μm to 5 mm.

[0026] <Operation of the fuel pump 10> When power is supplied to the motor unit 40 via the connector 23c, the armature 430 and the permanent magnet 41 act to rotate the armature 430 (clockwise), and the rotational force is transmitted to the impeller 32 of the pump unit 30 by the rotation center shaft 13. As a result, as shown in FIG. 2, the impeller 32 rotates within the pump flow path of the pump case 25, and the fuel drawn in through the fuel suction port 252e of the pump unit 30 is pressurized and discharged from the pump discharge port 251p into the housing unit 20. The fuel discharged from the pump discharge port 251p strikes the cover member 50 that covers the lower end side of the armature 430 and is guided to the periphery of the armature 430. The fuel then passes through the gap between the armature 430 and the permanent magnet 41, is guided to the upper part of the housing unit 20, and is discharged from the fuel discharge port 23p. At this time, the pressure of the fuel discharged from the fuel discharge port 23p is adjusted by the pressure adjustment valve 23v.

[0027] <Advantages of the fuel pump 10 according to this embodiment> In the fuel pump 10 according to this embodiment, the lower end of the armature 430, which faces the pump section 30, is covered by the cover member 50. Therefore, the cover member 50 prevents fuel discharged from the pump discharge port 251p from directly hitting the lower end of the armature 430, and the fuel is smoothly guided to the periphery of the armature 430. Furthermore, since the lower end of the armature 430 is covered by the cover member 50, this portion becomes relatively flat. This reduces the rotational resistance of the armature 430. Furthermore, the cover member 50 is made of a heat-dissipating material (aluminum), and the front and back sides of the cover member 50 are provided with concave-convex shapes 55r, 55e, 54d, and 54u. Therefore, the surface area of ​​the cover member 50 can be expanded by the concave-convex shapes, thereby improving the heat dissipation efficiency of the armature 430.

[0028] The concave-convex shapes 55r, 55e, 54d, and 54u of the cover member 50 are formed on both the front and back sides, and the concave-convex shapes 55e and 54u on the back side of the cover member 50 have a larger height difference than the concave-convex shapes 55r and 54d on the front side. That is, the concave-convex shapes 55r and 54d on the front side of the cover member 50, which directly hit the fuel discharged from the pump discharge port 251p and come into contact with the flowing fuel, have a smaller height difference than the concave-convex shapes 55e and 54u on the back side, so that the rotational resistance of the armature is not significantly increased. Furthermore, the height difference of the concave-convex shapes on the radially inner side of the predetermined surface on which the concave-convex shapes of the cover member 50 are formed is larger than the height difference of the concave-convex shapes on the radially outer side. That is, by making the height difference between the concave and convex shapes on the radially outer side, where the rotation speed is higher while the armature 430 is rotating, smaller than the height difference between the concave and convex shapes on the radially inner side, where the rotation speed is lower, the rotational resistance of the armature does not become too large.

[0029] The present invention is not limited to the above embodiment, and modifications are possible within the scope of the present invention. For example, in the present embodiment, the concave-convex shapes 55r, 55e, 54d, and 54u are formed on both the front and back sides of the cover member 50. However, the concave-convex shapes 55r, 55e, 54d, and 54u may be formed only on the back side of the cover member 50, or may be formed only on the front side of the cover member 50. Furthermore, in the present embodiment, the concave-convex shapes 55r, 55e, 54d, and 54u are formed on the angled portion 54 and the vertical wall portion 55 of the cover member 50. However, similar concave-convex shapes may also be formed on the front and back sides of the bottom plate portion 52. Furthermore, in the above embodiment, the angled portion 54 is formed on the cover member 50 to avoid interference with the lower bearing portion 251j. However, it is also possible to extend the overall length of the fuel pump and eliminate the angled portion 54, leaving only the bottom plate portion 52.

[0030] The uneven shape of the cover member 50 can also be formed by a plurality of radially arranged ridges 60, as shown in FIG. 6. The ridges 60 are preferably curved so as to be convex in the rotation direction (see the white arrows). The protrusion dimension of the ridges 60 is set to, for example, approximately 2 to 5 mm when formed on the front surface of the cover member 50, and approximately 2 to 8 mm when formed on the back surface. This improves the agitation of fuel during rotation of the armature 430. Furthermore, fuel is more likely to flow from the center to the radially outward direction. This improves the heat dissipation efficiency of the armature 430.

[0031] Here, even when forming the protrusions 60 on the cover member 50, it is possible to form the uneven shapes 55r, 55e, 54d, and 54u on both the front and back sides of the cover member 50. It is also possible to form the uneven shape 55r, etc. on either the front or back side of the cover member 50. In this case, as described above, the unevenness height difference dimension of the uneven shapes 54d and 54u on the radially inner side of a predetermined surface of the cover member 50 is set to be larger than the unevenness height difference dimension of the uneven shapes 55r and 55e on the radially outer side. Furthermore, the unevenness height difference dimension of the uneven shapes 55r and 54d on the front side of the cover member 50 is set to be smaller than the unevenness height difference dimension of the uneven shapes 55e and 54u on the back side.

[0032] In the present embodiment, an example has been shown in which the cover member 50 is made of aluminum, but it is also possible to use brass, copper, steel plate, etc. Also, in the present embodiment, an example has been shown in which the uneven shapes 55r, 55e, 54d, 54u or the ridges 60 are formed by press-forming the cover member 50. However, it is also possible to form the uneven shapes 55r, 55e, 54d, 54u of the cover member 50 or the ridges 60 by forging, casting, cutting, or the like. [Explanation of symbols]

[0033] 10. Fuel pump 20 Housing part 21 Housing body 252e·Fuel suction port 23p...Fuel discharge port 30 Pump section 251p··Pump outlet 40 Motor section 43 Rotor 430···Armature 50 Cover member 50m···Cover body 51...Terminal section 55r...1st uneven shape 55e...Second uneven shape 54d...Third uneven shape 54u···4th concave-convex shape 60····Protrusions (convex and concave shape)

Claims

1. A fuel pump that draws fuel from a fuel tank through a fuel suction port and discharges pressurized fuel from a fuel discharge port to supply the fuel to an internal combustion engine, a pump unit that pressurizes the fuel sucked through the fuel suction port and discharges the fuel from a pump discharge port; a motor unit that is a drive source for the pump unit and includes an armature that constitutes a rotor; a housing portion that houses the pump portion and the motor portion coaxially and is configured so that fuel discharged from the pump discharge port can pass around the armature of the motor portion and be discharged from the fuel discharge port, an axial end side of the armature facing the pump section is covered with a cover member; The cover member has an uneven surface formed on at least one of its front and back surfaces.

2. 2. A fuel pump according to claim 1, The concave-convex shape of the cover member is formed on both the front surface side and the back surface side, The fuel pump has a height difference dimension of the uneven shape on the rear surface side set to a value larger than a height difference dimension of the uneven shape on the front surface side.

3. 2. A fuel pump according to claim 1, a fuel pump in which, on a specific surface on which the uneven shape of the cover member is formed, the unevenness height difference dimension of the uneven shape on the radially inner side is set to a value greater than the unevenness height difference dimension of the uneven shape on the radially outer side.

4. 2. A fuel pump according to claim 1, The concave and convex shape of the cover member is a plurality of radially arranged ridges.

5. 5. A fuel pump according to claim 4, The protrusion is curved so as to be convex in the rotation direction of the armature.

6. 6. A fuel pump according to any one of claims 1 to 5, The cover member includes a cover main body portion that covers one axial end side of the armature and a terminal portion that is connected to the coil of the armature, and the cover main body portion and the terminal portion are integrally molded from the same metal.

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