JP2018150840A - Fuel pump - Google Patents

Abstract

A fuel pump that can be configured without using a metal housing is provided. A fuel pump (1) includes a pump case (11, 46) containing a stator core (2), a rotor (4) rotated by a rotating magnetic field formed on the inner peripheral side of the stator core (2), and an impeller (10) rotating integrally with the rotor (4). Pump parts 5 and 51 for sucking fuel and discharging it to the rotor 4 side, and resin housings 6 and 41 formed integrally with the stator core 2 by insert molding. The pump cases 11 and 46 and the resin housings 6 and 41 are joined by press fitting or snap fit. [Selection] Figure 1

Description

  The present invention relates to a fuel pump that is driven by rotation of a rotor arranged on the inner peripheral side of a stator core.

  2. Description of the Related Art Conventionally, there has been known a fuel pump configured to suck fuel by a rotating member that rotates integrally with a rotor disposed on the inner peripheral side of a stator core and discharge the fuel to the rotor side (see, for example, Patent Document 1). The fuel pump of Patent Document 1 includes a cylindrical metal housing. The metal housing has a convex portion with a smaller inner diameter on the inner peripheral side, and has a concave portion with an inner diameter larger than the convex portion on both sides in the axial direction.

  In this fuel pump, the stator core and the resin end cover are accommodated in one recess of the metal housing, and the pump case is accommodated in the other recess. The pump case and the impeller as a rotating member housed in the pump case constitute a pump unit that sucks fuel and discharges it to the rotor side. Thus, the fuel pump of patent document 1 is comprised by accommodating each component in a metal housing and couple | bonding each component.

Japanese Patent No. 4899991

  However, in the fuel pump of Patent Document 1, each component is housed in a metal housing and each component is coupled, so the outer periphery of the stator core is covered with the metal housing. For this reason, the metal housing increases the weight, diameter, and cost of the fuel pump.

  An object of the present invention is to provide a fuel pump that can be configured without using a metal housing, in view of the problems of the prior art.

The fuel pump according to the first invention is
A stator core;
A stator coil provided in the stator core for forming a rotating magnetic field on the inner peripheral side of the stator core;
A rotor that is disposed on the inner peripheral side of the stator core and rotates around a rotation axis by the rotating magnetic field;
A pump unit that rotates integrally with the rotor and a pump case that houses the rotating member, and sucks fuel by rotation of the rotating member and discharges the fuel to the rotor;
A resin housing formed integrally with the stator core by insert molding,
The pump case and the resin housing are joined by press fitting or snap fit.

  According to the first invention, since the pump case and the resin housing are coupled by press-fitting or snap-fit, the fuel pump is configured by coupling the pump unit and the resin housing without using a metal housing as in the prior art. can do. Thereby, the weight reduction, diameter reduction, and cost saving of a fuel pump can be achieved.

A fuel pump according to a second invention is the fuel pump according to the first invention,
The pump case includes a suction side case and a discharge side case,
The suction side case and the discharge side case form a pump chamber containing the rotating member therebetween,
One of the suction side case and the discharge side case is provided with an engagement portion fitted to the other outer peripheral portion at an end portion on the other side,
A caulking portion that caulks inward and connects the suction side case and the discharge side case to each other is provided at an end portion on the other side of the engagement portion.

  According to the second aspect of the invention, since both of the suction side case and the discharge side case are coupled by the caulking portion at the end of one of the engaging portions, it is necessary to use a member other than the suction side case and the discharge side case. The suction side case and the discharge side case can be coupled to each other.

A fuel pump according to a third aspect of the present invention is the first or second aspect of the invention,
The pump case is made of metal,
The pump case and the resin housing are joined by press fitting,
By the press-fitting, the inner peripheral portion of the pump case and the outer peripheral portion of the resin housing are joined.

  According to the third aspect of the invention, even if the resin portion of the resin housing absorbs fuel and swells at the joint portion between the inner peripheral portion of the pump case and the outer peripheral portion of the resin housing, the resin portion in the radial direction. Since the expansion of is regulated by the pump case made of metal, the bonding force is not weakened even if the mutual bonding force is improved instead. Therefore, the coupling between the pump case and the resin housing can be maintained firmly.

A fuel pump according to a fourth invention is the first or second invention,
The pump case and the resin housing are joined by a snap fit,
The coupling by the snap fit is
A plurality of projecting pieces extending from the resin housing to the pump case side and fitted to the outer periphery of the pump case, each having a recess or a protrusion,
This is realized by a convex portion or a concave portion provided on the outer periphery of the pump case and engaged with the concave portion or the convex portion of each protruding piece.

  According to the fourth aspect of the present invention, the resin housing and the pump case can be easily coupled to each other by snap fitting only by fitting the protruding piece of the resin housing to the outer periphery of the pump case.

A fuel pump according to a fifth aspect of the invention is any one of the first to fourth aspects of the invention,
One end side is connected to the stator coil, and the other end side is provided with a terminal exposed to the outside,
The resin housing is formed integrally with the stator core, the stator coil, and the terminal by insert molding.

  According to the fifth invention, since the resin housing is integrated with the stator core, the stator coil, and the terminal, handling this as one assembly part reduces the man-hours required for assembling the fuel pump and improves the efficiency of the assembly work. Can be achieved.

  A fuel pump according to a sixth aspect of the present invention includes the housing formed of resin so as to cover the entire fuel pump by insert molding in any of the first to fifth aspects of the invention.

  According to the sixth aspect of the invention, even if the housing does not cover the entire stator core, the portion of the stator core that is not covered by the housing is covered by the casing, so that fuel leaks from the inside of the fuel pump to the outside. Can be prevented.

It is sectional drawing which shows the structure of the fuel pump which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the fuel pump which concerns on another embodiment of this invention. It is a perspective view which shows the external appearance of the fuel pump of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the fuel pump 1 according to the embodiment includes a stator core 2, a stator coil 3 provided on the stator core 2, a rotor 4 disposed on the inner peripheral side of the stator core 2, and a rotor that sucks fuel. The pump part 5 discharged to the 4th side and the resin housing 6 integrally formed with the stator core 2 by insert molding are provided.

  The fuel pump 1 is used as an in-line type fuel pump disposed outside the fuel tank. In the following description, the lower side in FIG. 1 is referred to as “suction side”, and the upper side is referred to as “discharge side”.

  The stator coil 3 is for forming a rotating magnetic field on the inner peripheral side of the stator core 2. An insulator 7 is provided between the stator coil 3 and the stator core 2 to electrically insulate them. By controlling energization to the stator coil 3, a rotating magnetic field is formed in which the magnetic field moves in the circumferential direction along the inner periphery of the stator core 2.

  The rotor 4 includes a rotating shaft 8 and a permanent magnet 9 fixed around the rotating shaft 8, and rotates by receiving a force in a rotating direction from a rotating magnetic field by the permanent magnet 9. That is, the stator core 2, the stator coil 3, and the rotor 4 constitute a brushless motor.

  The pump unit 5 includes a resin impeller 10 as a rotating member that rotates integrally with the rotor 4 and a metal pump case 11 having a pump chamber in order to suck and discharge the fuel to the rotor 4 side. Prepare. The impeller 10 is fixed to the suction side end of the rotary shaft 8 and is accommodated in the pump chamber.

  That is, the pump unit 5 constitutes a cascade pump that rotates the disk-shaped impeller 10 at a high speed in the pump chamber, sucks fuel from the fuel inlet 12, boosts the pressure, and discharges the fuel to the rotor 4 side.

  The pump case 11 includes a discharge side case 13 and a suction side case 14, and a pump chamber is formed between them. The suction side case 14 is provided with the fuel suction port 12 and an axial bearing 15 for bearing the suction side end of the rotary shaft 8 in the axial direction. The discharge side case 13 is provided with a radial bearing 16 that radially supports the discharge side with respect to the impeller 10 of the rotary shaft 8.

  The discharge side case 13 includes an engaging portion 13 a fitted to the outer peripheral portion of the suction side case 14 at the end portion on the suction side case 14 side. At the end of the engaging portion 13a on the suction side case 14 side, a caulking portion 13b that caulks inward and connects the suction side case 14 and the discharge side case 13 to each other is provided. The suction side case 14 has a stepped portion 22 with which the caulking portion 13b is engaged.

  Contrary to this, the suction side case 14 has an engagement portion fitted to the outer peripheral portion of the discharge side case 13 at the end on the discharge side case 13 side, and the discharge side end of the engagement portion. A caulking portion that couples the suction side case 14 and the discharge side case 13 to each other may be provided in the portion.

  A protruding cylindrical portion 23 that protrudes toward the discharge side is provided at the center of the discharge side case 13 on the discharge side. The radial bearing 16 described above is provided on the inner peripheral side.

  The pump case 11 and the resin housing 6 are coupled by press-fitting. By this press-fitting, the inner peripheral portion of the pump case 11 and the outer peripheral portion of the resin housing 6 are joined. Even if the resin portion of the resin housing 6 absorbs fuel and swells at this joint portion, the expansion of the resin portion in the radial direction is restricted by the pump case 11 made of metal, so the joint force is On the other hand, even if it improves, it does not weaken.

  The resin housing 6 has one end connected to the stator coil 3 and the other end extended to the outside of the resin housing 6, a radial bearing 28 that radially supports the discharge-side end of the rotary shaft 8, A fuel discharge port 29 for supplying the fuel discharged from the pump unit 5 to the engine side is provided.

  Between the resin housing 6 and the radial bearing 28, a passage 30 through which fuel from the rotor 4 side toward the fuel discharge port 29 passes is provided. A check valve V for preventing a backflow that allows fuel to flow only from the passage 30 toward the fuel discharge port 29 is directed to the fuel discharge port 29.

  The resin housing 6 functions as an end cover that covers the discharge side end surface of the stator core 2, the portions of the stator coil 3 and the insulator 7 that protrude further to the discharge side, and the discharge side of the rotor 4.

  The resin housing 6 has an extending portion 31 that is provided on the inner peripheral surface of the stator core 2 and extends to the suction side from the suction side end surface of the stator core 2 through a groove that extends in the axial direction. The extending portion 31 covers and integrates the portions of the stator coil 3 and the insulator 7 that protrude from the suction side end face of the stator core 2 to the suction side. A gap 32 through which fuel discharged from the pump unit 5 passes is provided between the extending part 31 and the protruding cylindrical part 23 of the discharge side case 13.

  The extending portion 31 of the resin housing 6 has an outer diameter slightly smaller than that of the stator core 2. On the discharge side of the discharge side case 13, an annular groove 33 having a rectangular cross section opened to the discharge side is provided. In the annular groove 33, the gap 32, the extending portion 31 of the resin housing 6, and the portions of the stator coil 3 and the insulator 7 protruding from the suction side end surface of the stator core 2 to the suction side are arranged.

  The inner wall on the radially outer side of the annular groove 33 has substantially the same diameter as the outer peripheral surface of the extending portion 31. By press-fitting and joining the outer peripheral surface to the inner wall, the pump case 11 and the resin housing 6 are joined by press-fitting. An inner wall on the radially inner side of the annular groove 33 is an outer wall of the protruding cylindrical portion 23 described above.

  The fuel pump 1 further includes a housing 27 formed so as to cover the entire fuel pump 1 with resin by insert molding. The fuel suction port 12 protrudes to the suction side from the main suction side end face of the housing 27, and the inlet pipe attachment port 34 is part of the housing 27 so as to cover the periphery of the projecting fuel suction port 12. It is formed. A fuel pipe leading to a fuel tank (not shown) is attached to the inlet pipe attachment port 34.

  An outlet pipe attachment port 35 connected to the fuel discharge port 29 is formed as a part of the housing 27 so as to protrude from the discharge-side end surface of the housing 27. A fuel pipe connected to the engine side (not shown) is attached to the outlet pipe attachment port 35.

  A power feeding coupler 36 protruding from the side surface is provided on the side surface of the casing 27. In the power feeding coupler 36, a power feeding terminal 37 connected to the terminal 25 for feeding power to the stator coil 3 is provided.

  In assembling the fuel pump 1, the resin housing 6 is formed in advance by insert molding using the stator core 2, the insulator 7, the stator coil 3, and the terminal 25 as insert parts. Thereby, the stator assembly 38 in which these insert parts and the resin housing 6 are integrated is prepared. Then, the check valve V and the radial bearing 28 are assembled to the stator assembly 38.

  Next, the rotating shaft 8 of the rotor 4 is inserted into the radial bearing 28. Next, the discharge side case 13 is press-fitted into the outer periphery of the extending portion 31 of the resin housing 6.

  Next, the impeller 10 is inserted into the discharge side case 13, and the suction side case 14 is fitted to the engaging portion 13 a of the discharge side case 13. At this time, the vicinity of the suction side end of the rotary shaft 8 is inserted into the radial bearing 16 of the discharge side case 13. Further, the impeller 10 is fixed to the suction side end of the rotary shaft 8, and the axial bearing 15 in the suction side case 14 is brought into contact with the suction side end of the rotary shaft 8.

  Next, a caulking portion 13 b is formed by caulking the suction side end portion of the engaging portion 13 a toward the stepped portion 22 of the suction side case 14, and the discharge side case 13 and the suction side case 14 are coupled. As a result, the suction side case 14 is pushed to the protruding side by the caulking portion 13b, so that the opposing end surfaces of both the discharge side case 13 and the suction side case 14 are tightly sealed to form a pump chamber. Thus, a combined body in which the stator assembly 38 and the pump case 11 are integrally coupled is completed.

  Next, the casing 27 is formed by performing insert molding using a resin for the casing 27 by using the terminal with the power supply terminal 37 connected to the terminal 25 of the completed combined body as an insert part. Thereby, the fuel pump 1 is completed.

  As described above, according to the present embodiment, since the pump case 11 and the resin housing 6 are coupled by press fitting, the pump unit 5 and the resin housing 6 are coupled without using a metal housing that has been conventionally used. Thus, the fuel pump 1 can be configured. Thereby, the weight reduction, diameter reduction, and cost saving of the fuel pump 1 can be achieved.

  In addition, since the suction side case 14 and the discharge side case 13 are coupled by the caulking and crimping portion 13b at the end of the engagement portion 13a of the discharge side case 13, the suction side case 14 and the discharge side case 13 are not connected. The suction side case 14 and the discharge side case 13 can be coupled without using other members.

  Further, since the inner peripheral portion of the pump case 11 and the outer peripheral portion of the extending portion 31 of the resin housing 6 are joined by press-fitting, even if the resin portion of the extending portion 31 absorbs fuel and swells, Since the expansion of the resin portion in the radial direction is restricted by the pump case 11 made of metal, the mutual bonding force is not weakened even if it is improved. Therefore, the coupling between the pump case 11 and the resin housing 6 can be maintained firmly.

  Further, since the resin housing 6 constitutes a stator assembly 38 integrated with the stator core 2, the stator coil 3, the terminal 25, and the fuel discharge port 29, the fuel pump 1 is handled by handling this as one assembly part. The number of man-hours required for assembling the portion accommodated in the housing 27 can be reduced and the efficiency of the assembling work can be improved.

  Further, since the casing 27 covers the entire fuel pump 1, the portion of the stator core 2 that is not covered by the housing 6 is also covered by the casing 27. For this reason, it is possible to prevent the fuel from leaking from the inside of the fuel pump 1 through the stator core 2 to the outside.

  FIG. 2 shows the structure of a fuel pump according to another embodiment of the present invention. FIG. 3 is a perspective view of the fuel pump 40. 2 and 3, the same reference numerals as those in FIG. 1 denote the same elements. As shown in FIGS. 2 and 3, the fuel pump 40 employs a resin housing 41 that covers the entire outer periphery of the stator core 2 as the resin housing. Therefore, the thing corresponding to the housing | casing 27 in the Example of FIG. 1 is unnecessary.

  The resin housing 41 has an extending portion 42 that extends to the suction side from the stator core 2 while maintaining the outer diameter. The extension portion 42 covers and is integrated with the portions of the stator coil 3 and the insulator 7 that protrude from the suction side end face of the stator core 2 to the suction side, but further extends to the suction side and has a smaller inner diameter. It has a cylindrical end 43 that is thick.

  A plurality of projecting pieces 45 extending to the suction side and having recesses 44 are provided at the suction side end of the cylindrical end portion 43. The discharge side case 47 constituting the pump case 46 has an outer peripheral surface 48 in which a plurality of projecting pieces 45 are fitted to the outside, and a press-fitting portion 49 having a step on the discharge side and having a reduced diameter.

  The outer peripheral surface 48 of the discharge side case 47 is provided with a convex portion 50 that engages with the concave portion 44 of each protruding piece 45. The projecting piece 45 and the convex portion 50 of the outer peripheral surface 48 constitute a snap-fit mechanism that couples the resin housing 41 and the pump case 46. Note that the concave portion and the convex portion may be reversed, and a concave portion may be provided on the outer peripheral surface 48 of the discharge side case 47, and the convex portion 45 may be provided with a convex portion that engages with the concave portion.

  Further, the discharge side case 47 includes an engagement portion 47 a fitted to the outer peripheral portion of the suction side case 14 at the end portion on the suction side case 14 side. At the end of the engaging portion 47a on the suction side case 14 side, there is provided a caulking portion 47b that caulks inward and connects the suction side case 14 and the discharge side case 47 to each other. The pump unit 51 includes a pump case 46 and the impeller 10. Regarding the configuration other than the above configuration, the fuel pump 40 of the present embodiment has the same configuration as that of the embodiment of FIG.

  In assembling the fuel pump 40, the resin housing 41 is formed in advance by insert molding using the stator core 2, the insulator 7, the stator coil 3, and the terminal 25 as insert parts. Thereby, the stator assembly 52 in which these insert parts and the resin housing 41 are integrated is formed. Then, the check valve V is assembled to the stator assembly 52.

  Next, the rotating shaft 8 of the rotor 4 is inserted into the radial bearing 28. Next, the press-fit portion 49 of the discharge side case 47 is press-fitted into the inner periphery of the cylindrical end portion 43 of the resin housing 41, and at the same time, the protruding piece 45 of the resin housing 41 is fitted to the outer peripheral surface of the discharge side case 47. At this time, the vicinity of the suction side end of the rotary shaft 8 is inserted into the radial bearing 16 of the discharge side case 47.

  As a result, the gap between the press-fit portion 49 and the cylindrical end portion 43 is sealed so as not to leak fuel, and the convex portion 50 of the discharge side case 47 engages with the concave portion 44 of the projecting piece 45 to snap. The resin housing 41 and the discharge side case 47 are coupled by the fit.

  Next, the impeller 10 is inserted into the discharge side case 47, and the suction side case 14 is fitted into the engaging portion 47 a of the discharge side case 47. Further, the impeller 10 is fixed to the suction side end of the rotary shaft 8, and the axial bearing 15 in the suction side case 14 is brought into contact with the suction side end surface of the rotary shaft 8.

  Next, a caulking portion 47 b is formed by caulking the suction side end of the engaging portion 47 a toward the stepped portion 22 of the suction side case 14, and the discharge side case 47 and the suction side case 14 are coupled. As a result, the suction side case 14 is pushed to the projecting side by the caulking portion 47b, so that the opposing end surfaces of both the discharge side case 47 and the suction side case 14 are tightly sealed to form a pump chamber. Thereby, the stator assembly 52 and the pump case 46 are integrally coupled, and the fuel pump 1 is completed.

  As described above, according to this embodiment, since the snap fit mechanism for coupling the pump case 46 and the resin housing 41 is provided, the protruding piece 45 of the resin housing 41 is attached to the outer peripheral surface 48 of the discharge side case 47. The resin housing 41 and the discharge side case 47 can be easily coupled by snap fitting simply by fitting.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this. For example, as the pump units 5 and 51, other types, for example, a spiral pump or a turbine pump may be adopted.

  Further, the insulator 7 does not have to be provided between the stator coil 3 and the stator core 2 as long as the insulation between the stator coil 3 and the stator core 2 is ensured by the covering of the stator coil 3 or the like.

  Further, the fuel pump 1 of FIG. 1 may be disposed in the fuel tank and used as an in-tank type fuel pump in a state where the housing 27 is not provided.

  DESCRIPTION OF SYMBOLS 1, 40 ... Fuel pump, 2 ... Stator core, 3 ... Stator coil, 4 ... Rotor, 5, 51 ... Pump part, 6, 41 ... Resin housing, 7 ... Insulator, 8 ... Rotating shaft, 9 ... Permanent magnet, 10 ... Impeller, 11, 46 ... pump case, 12 ... fuel suction port, 13, 47 ... discharge side case, 13a, 47a ... engagement portion, 13b, 47b ... caulking portion, 14 ... suction side case, 15 ... axial bearing, 16 DESCRIPTION OF SYMBOLS ... Radial bearing, 22 ... Step part, 23 ... Projection cylindrical part, 25 ... Terminal, 27 ... Housing, 28 ... Radial bearing, 29 ... Fuel outlet, 30 ... Passage, 31 ... Extension part, 32 ... Gap, 33 An annular groove, 34 an inlet pipe attachment port, 35 an outlet pipe attachment port, 36 a power feeding coupler, 37 a power feeding terminal, 38, 52 a stator assembly, 42 an extension part, 43 a cylindrical end part, 44 ... Parts, 45 ... projection piece, 48 ... outer circumferential surface, 49 ... press-fit portion 50: convex portion, V ... check valve.

Claims (6)

A stator core;
A stator coil provided in the stator core for forming a rotating magnetic field on the inner peripheral side of the stator core;
A rotor that is disposed on the inner peripheral side of the stator core and rotates around a rotation axis by the rotating magnetic field;
A pump unit that has a rotating member that rotates integrally with the rotor and a pump case that houses the rotating member, and sucks fuel by the rotating member and discharges the fuel to the rotor side;
A resin housing formed integrally with the stator core by insert molding,
The fuel pump in which the pump case and the resin housing are coupled by press fitting or snap fit. The pump case includes a suction side case and a discharge side case,
The suction side case and the discharge side case form a pump chamber containing the rotating member therebetween,
One of the suction side case and the discharge side case is provided with an engagement portion fitted to the other outer peripheral portion at an end portion on the other side,
2. The fuel according to claim 1, wherein an end portion on the other side of the engagement portion is provided with a caulking portion that is caulked inward to couple the suction side case and the discharge side case to each other. pump. The pump case is made of metal,
The pump case and the resin housing are joined by press fitting,
The fuel pump according to claim 1 or 2, wherein an inner peripheral portion of the pump case and an outer peripheral portion of the resin housing are joined by the press-fitting. The pump case and the resin housing are joined by a snap fit,
The coupling by the snap fit is
A plurality of projecting pieces extending from the resin housing to the pump case side and fitted to the outer periphery of the pump case, each having a recess or a protrusion,
The fuel pump according to claim 1 or 2, wherein the fuel pump is realized by a convex portion or a concave portion provided on an outer periphery of the pump case and engaged with a concave portion or a convex portion of each protruding piece. One end side is connected to the stator coil, and the other end side is provided with a terminal exposed to the outside,
The fuel pump according to any one of claims 1 to 4, wherein the resin housing is formed integrally with the stator core, the stator coil, and the terminal by insert molding.   The fuel pump according to any one of claims 1 to 5, further comprising a housing made of resin so as to cover the entire fuel pump by insert molding.