JP6689127B2 - Fuel pump - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump, and more particularly to a motor that is a drive source of a fuel pump, in which the stator and rotor of a motor and the axial centering of the rotor and the pump base are highly accurate, and the fuel is small and highly efficient. It relates to the pump.

  It is known that a brushless motor is used as a drive source of a fuel pump and fuel boosted by the pump is discharged through the motor. The brushless motor is suitable for improving the efficiency of the fuel pump because the commutator and the brush do not slide and the voltage drop does not occur in this portion, and it is easy to improve the efficiency of the motor.

  Here, the efficiency of the fuel pump is the ratio of the work amount of the fuel pump (fuel discharge pressure) x (fuel discharge amount) to the electric power supplied to the fuel pump. If the efficiency of the fuel pump is improved, the power supplied to the fuel pump can be reduced and the fuel pump can be downsized. Based on this viewpoint, in order to reduce the outer diameter of the motor part, a protrusion is formed between the pump part and the motor part on the inner peripheral side of the housing formed of a thin plate having a substantially uniform thickness. Is formed, two concave portions are provided so as to sandwich the protruding portion, the pump portion is accommodated in one concave portion, and the motor portion is accommodated in the other concave portion. That is, it has a configuration of supporting the bearings of the pump unit and the motor unit via the housing (for example, refer to Patent Document 1).

  Further, in the fuel pump capable of suppressing the occurrence of vapor lock by increasing the discharge flow rate, the casing of the pump portion has a discharge hole penetrating from the bottom surface of the booster flow passage to the discharge side cover side, and the boosted fuel is the discharge hole, the fuel It is guided to the discharge flow path via the flow path and discharged from the discharge port. The fuel flow path is shown to be formed between the housing and the stator, and has a structure for supporting the bearings of the pump section and the motor section via the housing, as in the case of Patent Document 1. (For example, see Patent Document 2).

Japanese Patent No. 4893991 JP, 2005-86804, A

  However, in the technique disclosed in Patent Document 1, one of the bearings that supports the rotor of the fuel pump is provided in the end cover of the motor unit, and the other one is provided in the pump case. Is a configuration performed through the housing. That is, due to the axial misalignment between the end cover connected to the stator core and the housing and the axial misalignment between the pump case and the housing, the axial center of the rotor shaft is misaligned, and this axial misalignment increases the load applied to the bearings, causing friction. There is a problem in that the efficiency of the fuel pump is reduced due to an increase in the torque and an extra torque (current) required for the motor.

  Further, in the technique disclosed in Patent Document 2 as well, like the Patent Document 1, there is a possibility that the axial center of the rotating shaft may shift, and the fuel flow path is partitioned between the housing and the stator. However, there is a problem that the structure is not suitable for reducing the diameter of the fuel pump.

  The present invention has been made to solve the above problems, and makes it possible to realize a structure for aligning the center axes of rotating shafts more easily and with high accuracy, and boosting the pressure by rotating the impeller. An object of the present invention is to provide a fuel pump having a downsized structure by optimizing the position of a passage hole through which the fuel passes and by allowing the fuel passing through the motor chamber to flow between the rotor and the stator.

A fuel pump according to the present invention is a fuel pump that sucks fuel, boosts the pressure, and discharges the fuel to the outside. The fuel pump has a rotary shaft common to the pump unit, drives an impeller of the pump unit, and is installed above the pump unit. and a motor unit having a position coil and the stator consisting of a stator core, a pump base of the pump portion is a bearing portion is provided for supporting the rotary shaft, the stator of the motor unit, the motor unit A resin-made stator mold that covers the entire stator is provided so that the outer wall of the insulator that houses the coil located on the pump side protrudes toward the pump side, and the stator mold is provided above the stator mold. a bearing portion for supporting the rotary shaft, a discharge port is provided in the fuel, the stator contact surface of the outer wall of said insulator is the Pont Together contacts the outer peripheral surface of the inner upward cylindrical protrusion provided on the base, the lower end surface of the stator mold is supported by contact with the upper surface of the inner upward cylindrical protrusion, the cylindrical housing The pump portion and the motor portion are provided so as to communicate with each other at an outer diameter portion, the housing is abutted on a circumferential abutment surface of the pump base, and is supported on a support surface of the pump base, and The housing is composed of a caulking portion of a pump cover provided with the fuel inlet of the pump portion and a caulking portion of an upper portion of the stator mold.
Further, the fuel pump of the present invention is a fuel pump that sucks fuel, boosts the pressure, and discharges the fuel to the outside. The fuel pump has a rotating shaft common to the pump unit and drives the impeller of the pump unit, A motor unit having a stator formed of a coil and a stator core located at an upper portion, a pump base of the pump unit is provided with a bearing unit for supporting the rotary shaft, and the stator of the motor unit has the A resin-made stator mold that covers the entire stator is provided such that inner walls of a predetermined number of insulators that house the coils and that are located on the pump side of the motor section protrude toward the pump side. A bearing portion that supports the rotating shaft and a discharge port for the fuel are provided on the upper part of the mold, and the stator contacts the inner wall of the insulator. The surface is supported by contacting the outer peripheral surface of the groove provided in the pump base, and the lower end surface of the stator mold by contacting the upper surface of the upward cylindrical protrusion provided in the pump base. A cylindrical housing is provided so as to communicate with the pump portion and the motor portion and to come into contact with each other at an outer diameter portion, and the housing abuts on a circumferential abutment surface of the pump base and a supporting surface of the pump base. The housing is supported and is composed of a caulking portion of the pump cover in which the fuel inlet of the pump portion is provided, and a caulking portion of the upper portion of the stator mold.

Since the fuel pump of the present invention employs the above-described configuration, the stator core of the motor unit and the pump base of the pump unit can be directly aligned with each other, and therefore the motor unit and the pump unit can be accurately aligned. By enabling centering and reducing the axis deviation, it is possible to suppress excessive torque in the motor section, which contributes to higher efficiency of the fuel pump.
In addition, since the housing is supported by the supporting surface of the pump base, it is supported by a large area, the supporting rigidity of the housing is improved, and the deformation can be suppressed.

FIG. 3 is a sectional view of the fuel pump according to the first embodiment. FIG. 3 is a front view of the impeller according to the first embodiment. FIG. 3 is a plan view of the pump base according to the first embodiment. FIG. 3 is a plan view of the pump cover according to the first embodiment. FIG. 3 is a perspective view of a stator core according to the first embodiment. FIG. 3 is a perspective view of the insulator according to the first embodiment. 3 is a front view of the stator according to the first embodiment. FIG. FIG. 7 is a sectional view of a fuel pump according to a second embodiment. FIG. 7 is a sectional view of a fuel pump according to a third embodiment. FIG. 9 is a sectional view of a fuel pump according to a fourth embodiment.

Embodiment 1.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the fuel pump 1. The fuel pump 1 is composed of a motor unit 2 shown in the upper part of FIG. 1 and a pump unit 3 shown in the lower part of FIG. The outside of the motor unit 2 and the pump unit 3 is fixed via a housing 4 which is a cylindrical member that communicates with each other. The motor unit 2 is composed of a stator 19 and a rotor 20, and the pump unit 3 is composed of a pump base 5, an impeller 6, and a pump cover 7.

  FIG. 2 shows a front view of the impeller 6. The impeller 6 is substantially disc-shaped, and a blade groove 6B that is continuous in the circumferential direction is formed in an annular shape at a predetermined distance from the outer peripheral wall 6A, and a cross section that penetrates in the axial direction is approximately D in the central portion. A shaft hole 44 having a character shape is formed, and the rotary shaft 27 is engaged with the shaft hole 44. When the coil 22 of the motor unit 2 which will be described later is excited, the rotating shaft 27 rotates, which causes the impeller 6 to rotate.

  FIG. 3 shows a plan view of the pump base 5 as seen from the impeller 6 side. As shown in FIG. 1, the pump base 5 has a cylindrical shape in which a bearing portion 12 is provided in the central portion, and has a substantially H-shaped cross section. An impeller chamber 8 for accommodating the impeller 6 is provided inside, and a channel groove 17A shown in FIG. 3 is provided in a C-shape on the side of the impeller 6 shown in FIG. The flow channel 17A has a semicircular cross section as shown in FIG.

  The impeller chamber 8 is provided on the outer diameter side of the pump base 5 with a downward cylindrical protrusion 5A having a length larger than the axial dimension of the impeller 6 and protruding downward in a direction opposite to the motor unit 2. Has been. At the lower end of the downward cylindrical protruding portion 5A, an abutting surface 5F that contacts the pump cover 7 is provided. A passage hole 13 communicating with the motor unit 2 is provided at the end of the flow path groove 17A. The outer edge of the common hole 13 is set at a position at a distance R3 from the center of the shaft.

  As shown in FIG. 1, the upward cylindrical protrusion 5 </ b> B protruding toward the motor unit 2 in the opposite direction to the downward cylindrical protrusion 5 </ b> A of the pump base 5 is in contact with the outer diameter of the stator core 21 of the motor unit 2. It has a surface 5C and a support surface 5D provided so as to support the stator core 21 at the lower end of the stator core 21. A circumferential contact surface 5E that contacts the housing 4 and a support surface 5G that supports the housing 4 are provided on the outer diameter portion of the upward cylindrical protrusion 5B. Further, the bearing portion 12 of the pump base 5 is provided with a cylindrical bearing 12B. Although the bearing 12B is provided as a separate body from the pump base 5, the bearing portion 12 may be provided only with the pump base 5 and the bearing 12B is not provided.

  The radius R1 of the contact surface 5C of the upward cylindrical protrusion 5B has the same dimension as the outer radius R1 of the stator core 21, and the axial center of the outer edge of the passage hole 13 provided at the end of the flow passage groove 17A of the pump base 5. Although the distance R3 from R is smaller than the radius R1 of the contact surface 5C in FIG. 1, the flow path groove 17A may be provided so that the outer edge exists at a position where the relationship of R1 ≧ R3 is established.

  FIG. 4 shows a plan view of the cylindrical pump cover 7 viewed from the impeller 6 side. The pump cover 7 is provided with a flow path groove 17B having the same shape and shape as the flow path groove 17A of the pump base 5 on the side facing the impeller 6. A suction port 16 through which fuel is sucked is provided at the starting point of the flow channel 17B. A suction port 16 for sucking fuel is provided at the starting point of the flow passage groove 17B, and a vapor hole 7A is provided in the middle of the flow passage groove 17B to connect the impeller chamber 8 and the outside of the fuel pump 1. It is a through hole for connecting surfaces. Further, the outer peripheral portion of the upper surface of the pump cover 7 contacts the contact surface 5F provided on the pump base 5. Further, although the plain bearing portion 14B of the pump cover 7 is provided with the separate plain bearing 14B, it may be a plain bearing portion 14 that is composed of only the pump cover 7 and is not provided with the plain bearing 14B.

  The motor unit 2 is composed of a stator 19 and a rotor 20. As shown in FIGS. 1 and 5 to 7, the stator 19 is wound around the stator core 21, the insulating insulator 26 that houses the coil 22 attached to the stator core 21, and the stator core 21 via the insulator 26. It has a coil 22, and a stator mold 23 that covers the coil 22 and the stator core 21 with a resin member. The stator core 21 includes a cylindrical core back 21D having an outer diameter, teeth 21E projecting from the core back 21D in the inner diameter direction, and magnetic pole surfaces 21C extending from the teeth 21E in the circumferential direction. The stator 19 of the first embodiment has twelve divided stator cores 21 as shown in FIG. 7, and is configured by laminating a plurality of thin plates. The outer diameter and the inner diameter of the stator core 21 are coaxial.

  A perspective view of the insulator 26 is shown in FIG. The insulator 26 of FIG. 6 shows a half length in the axial direction, and the insulator provided at the lower portion in the axial direction of FIG. 1 is the upper side. The insulator 26 has an outer wall 26A axially extending in an outer diameter portion thereof, an inner wall 26F axially extending in an inner diameter portion thereof, and a coil 22 wound in a space between the outer wall 26A and the inner wall 26F in the radial direction. And a winding frame portion 26C to be wound. Further, the teeth fitting portion 26G is provided in a direction opposite to the direction in which the outer side wall 26A and the inner side wall 26F extend. Although not shown, an insulator 26 provided on the upper portion of the motor portion 2 of the fuel pump 1, that is, on the axially opposite side of the pump portion 3 is provided with a groove for inserting a terminal, and the other portions are provided. It has the same configuration as in FIG.

  FIG. 7 shows a state in which the insulator 26 is fitted in the stator core 21 and arranged in an annular shape. This drawing is a plan view showing the stator 19 as viewed from the impeller 6 side in FIG. 1, and is configured by omitting the coil 22 and mounting the insulator 26 on the teeth 21E of the stator core 21. The plurality of stator cores 21 have split surfaces integrally formed into an annular shape by welding or bonding.

  The winding start wire and the winding end wire of the coil 22 are fixed to the terminals. This terminal is electrically conductive, is fixed to the insulator 26, and protrudes from the stator mold 23 in the axial direction. The motor unit 2 can be driven by externally applying a power source to the protruding portion.

  The lower end outer peripheral surface 21A of the stator core 21 radially abuts on an abutment surface 5C provided on the pump base 5, and the lower end surface 21B abuts a support surface 5D provided on the pump base 5 to support the stator 19. To be done. The resin of the stator mold 23 is not covered on the portions of the stator core 21 corresponding to the contact surface 5C and the support surface 5D.

  The stator mold 23 includes a discharge port 24 that discharges fuel to a position axially opposite to the suction port 16 provided in the pump cover 7 of the pump unit 3, a caulking portion 28B that abuts the housing 4, and a bearing portion of the rotating shaft 27. Has 25. The bearing 25B fitted into the bearing insertion surface 25C of the bearing portion 25 is inserted, and the rotary shaft 27 is inserted into the inner diameter portion of the bearing 25B. In the first embodiment, the stator mold 23 and the bearing 25B are configured by different individuals, but the present invention is not limited to this, and may be configured by only the stator mold 23, for example.

  The discharge port 24 is provided with a check valve 31. The check valve 31 is composed of a lid 30 and a spring 29. When the pressure of the fuel boosted by the pump unit 3 exceeds a predetermined pressure, the spring 29 contracts and the lid 30 moves upward in FIG. Fuel is discharged from the outlet 24.

  The rotor 20 is rotatably installed on the inner peripheral side of the stator core 21, and has permanent magnets formed on the outer peripheral surface facing the stator core 21 and having different magnetic poles alternately in the rotational direction, and a rotary shaft that rotates about the central axis of the permanent magnet. Has 27. There are two bearings 25B for the stator 19 and a bearing 12B for the pump base 5 at both ends of the rotary shaft 27 in the axial direction. The rotary shaft 27 is supported by the two bearings 12B and 25B. The permanent magnet (not shown) of the first embodiment has 12 magnetic poles in the circumferential direction.

  The housing 4 made of a metal material is provided with crimped portions 4A and 4B at both ends in the axial direction, and has a shape inclined to the inner diameter side with respect to the outer diameter of the housing 4. The caulking portion 4A contacts the caulking portion 28A of the pump cover 7 on the suction port 16 side. The caulking portion 4B contacts the caulking portion 28B of the stator mold 23 on the discharge port 24 side. That is, the caulking portions 4A and 4B contact the conical caulking portions 28A and 28B, respectively.

  A method of manufacturing the fuel pump 1 having such a configuration will be described. First, the stator core 21 is manufactured by pressing a thin iron plate and stacking a plurality of the thin iron plates. After attaching the insulator 26 to the stator core 21, the coil 22 is wound. Incidentally, the winding start and winding end wires of the coil 22 are connected to terminals. After this winding work, the stator core 21, the insulator 26, the coil 22, and the terminal are put into a resin molding die (molding die) and resin molding is performed.

  As a result, the stator mold 23 in which all the coils 22 are covered with the resin is formed. In the first embodiment, as described above, the stator mold 23 does not cover the entire length of the stator core 21 as shown in FIG. Next, the bearing portion 25 of the stator mold 23 is cut. This cutting process naturally processes the outer diameter of the stator core 21 and the bearing insertion surface 25C of the bearing portion 25 into a coaxial core. Next, the bearing 25B is press-fitted and fixed to the bearing insertion surface 25C of the bearing portion 25.

  At this time, since the outer diameter and the inner diameter of the bearing 25B are formed so that the central axes thereof are determined by the accuracy of the bearing 25B, the bearing 25B and the central axis of the stator 19, that is, the rotary shaft 27 are accurately aligned. be able to. In this way, the deviation between the central axes of the bearing 25B and the stator core 21 can be set accurately, and the axis alignment can be performed with high accuracy.

  The rotor 20 is manufactured by integrally molding a plastic magnet, which is a permanent magnet (not shown), on the rotating shaft 27. The plastic magnet is formed into a cylindrical shape by adding magnetic powder to a thermoplastic resin material such as PPS (polyphenylene sulfide) or POM (polyacetal).

  The abutment surface 5C of the pump base 5 and the bearing insertion surface 12C of the bearing portion 12 are formed so as to be coaxial, and the bearing 12B is press-fitted into the bearing insertion surface 12C of the bearing portion 12 to fix the pump base. The abutment surface 5C of the rotary shaft 5 and the rotary shaft 27 can be aligned with high accuracy. The pump base 5 of the first embodiment is a die cast of aluminum, and by performing cutting after die casting, the contact surface 5C and the bearing insertion surface 12C of the bearing portion 12 can achieve a high degree of coaxiality. You can Further, the supporting surface 5D, the peripheral contact surface 5E, the contact surface 5F, and the supporting surface 5G that supports the housing 4 are also machined to enable highly accurate positioning.

  Next, the housing 4 is press-fitted so as to be joined at the peripheral contact surface 5E of the pump base 5. At this time, the housing 4 can be supported by the support surface 5G of the pump base 5 and the rigidity can be improved to determine the axial position. Thereby, the housing 4 and the pump base 5 can be fixed.

  Next, the rotating shaft 27 of the rotor 20 is put in the bearing 25B of the stator 19 and the rotor 20 is put in the stator 19. At this time, a force is generated so that the permanent magnet of the rotor 20 and the stator core 21 of the stator 19 are attracted by a magnetic attraction force. Therefore, even if the lower side of the rotor 20 shown in FIG. The rotor 20 does not fall. Therefore, it is not necessary to hold the rotor 20 by the device so as not to drop it, and the device cost can be suppressed.

  With the rotor 20 kept in the stator 19, the rotary shaft 27 is put in the bearing 12B of the pump base 5 fixed to the housing 4. At the same time, the contact surface 5C of the pump base 5 and the lower end outer peripheral surface 21A of the stator core 21, and the support surface 5D of the pump base 5 and the lower end surface 21B of the stator core 21 are brought into contact. In the first embodiment, the contact surface 5C of the pump base 5 is fixed by press-fitting the lower end outer peripheral surface 21A of the stator core 21, but the contact surface 5C is not limited to press-fitting, and this may be a clearance fit or the like.

  Next, the caulking portion 4A that abuts the stator mold 23 is formed by pressing the axial end surface of the housing 4 on the discharge port 24 side so as to incline in the inner diameter direction. At this time, a load is applied via the housing 4, and this load can be received by the support surface 5D of the pump base 5 having a wide support area. Since the support surface 5D is composed of the stator core 21 made of a metal material and the pump base 5, the amount of deformation can be suppressed more than when a load is applied by resin. Further, since the circumferential contact surface 5E is press-fitted, the housing 4 can be caulked with a larger force, and the fuel leakage can be prevented.

  Next, the impeller 6 is put into the rotary shaft 27, placed in the impeller chamber 8, and the flat bearing 14B press-fitted into the flat bearing portion 14 of the pump cover 7 is put into the housing 4. At this time, the contact surface 5F of the pump base 5 and the contact surface of the pump cover 7 are axially opposed to each other. In this state, the housing 4 and the pump cover 7 are brought into contact with each other by pressurizing the axial end surface of the housing 4 on the suction port 16 side so as to incline in the inner diameter direction, and the caulked portion 4B is formed. In this step, the contact surface 5F of the pump base 5 contacts and closely contacts the pump cover 7.

  In the fuel pump 1 manufactured in this way, the rotor 20 rotates when the power is supplied from the terminal, and the impeller 6 rotates. When the impeller 6 rotates, the fuel is carried into the pump unit 3 from the suction port 16. Further, the pressure of the fuel is increased by the rotation of the impeller 6, the fuel passes through the passage hole 13 and is conveyed to the motor unit 2. The fuel carried to the motor unit 2 passes through the gap between the rotor 20 and the stator 19 as a flow path, and is discharged from the discharge port 24 to the outside.

  The fuel pump 1 having such a configuration has the following effects. In the first embodiment, the lower end outer peripheral surface 21A of the stator core 21 of the stator 19 and the contact surface 5C of the pump base 5 are brought into contact with each other. When the stator and the housing and the pump base and the housing are axially aligned as in the prior art document 1, an axial deviation due to a component called the housing is included. However, in the first embodiment, the axial alignment can be directly performed, and therefore high accuracy is achieved. Centering is possible.

  Therefore, the central axes of the stator core 21, the pump base 5, and the rotor can be easily aligned with high accuracy. If this axis deviation is large, the load applied to the bearing will be large, friction will be large, and extra motor torque (current) will be required as compared with the case where the axis deviation is small, and the efficiency of the fuel pump 1 will decrease. Resulting in. In the first embodiment, it is possible to reduce the axis deviation, so that it is possible to suppress the need for extra motor torque (current), which contributes to higher efficiency of the fuel pump 1. You can

  Further, in the first embodiment, the lower end surface 21B of the stator core 21 of the stator 19 is supported by the support surface 5D of the pump base 5. The housing 4 is supported by the support surface 5G of the pump base 5. By doing so, the axial load applied when the housing 4 is caulked can be received by the supporting surfaces 5D and 5G made of a metal material having higher rigidity than the resin material. As a result, even if the caulking portion 4A is pressed with a stronger axial force, deformation of the support surfaces 5D, 5G and the periphery thereof can be suppressed, and highly accurate assembly can be performed. Further, since the caulking portion 4A can be firmly fixed, the fuel sealability is improved, which can contribute to further increase in efficiency of the fuel pump 1.

Further, the pump base 5 and the housing 4 were press-fitted at the peripheral contact surface 5E. As a result, the pump base 5 and the housing 4 can be easily fixed integrally.
Further, at the axial end surface of the housing 4, the caulking portion 4B is inclined toward the inner diameter side with respect to the outer diameter of the housing 4, so that the pump cover 7 and the housing 4 are brought into contact with each other at the caulking portion 4B.

  As a result, surface pressure can be applied to the contact surface 5F of the pump base 5 and the pump cover 7, and the adhesion of the contact surface 5F is improved, so that fuel is prevented from leaking out of the impeller chamber 8. You can Further, the pump cover 7 can be fixed while being pressed against the pump base 5 side by the caulking portion 4B. Since the caulking portions are provided on both axial sides including the caulking portion 4A, the pump portion 3 and the motor portion 2 can be easily fixed.

  Further, since the housing 4 that covers the outer diameter side of the motor portion 2 and the pump portion 3 is adopted, the sound generated in the fuel pump 1 (such as the rotation noise of the impeller 6 and the electromagnetic noise of the motor) leaks to the outside of the fuel pump 1. It can be made difficult and the noise value can be suppressed. Further, since the housing 4 made of a metal material is provided, rigidity can be increased and vibration can be suppressed.

  Further, the stator 19 is brought into contact with the lower end outer peripheral surface 21A of the stator core 21 at the contact surface 5C of the pump base 5. Since the stator core 21 is an iron-based member punched by a press, the accuracy (concentricity of the inner diameter of the stator core 21 and the outer diameter of the stator core 21) is good. Therefore, since the stator core 21 with high accuracy can be used for axis alignment, it is not necessary to cut the contact surface 5C after the stator mold 23, and the number of processing steps can be reduced.

  In the first embodiment, the magnetic poles of the stator 19 are the stator core 21 divided for each tooth 21E, but the present invention is not limited to this. For example, all the magnetic poles are not divided and the stator core 21 is a pair. Is also effective against. If the stator core 21 is integrated, deviation of each component can be suppressed, so that assembly with higher accuracy can be performed and high-precision centering can be performed.

  In addition, the through hole 13 provided in the pump base 5 is located at the position of the distance R3 on the contact surface 5C, that is, on the inner diameter side of the outer radius R1 of the stator core 21, and outside the inner radius R2 of the stator core 21. (R1 ≧ R3> R2). When R3 ≦ R2, the through hole 13 is arranged on the inner diameter side of the stator core 21. In this case, the outer diameter of the impeller 6 must be smaller than the inner radius R2 of the stator core 21, and it is necessary to increase the rotation speed in order to obtain the required flow rate. Therefore, soundproofing measures may be required. However, according to the first embodiment, since the impeller 6 having a larger outer diameter can be used, the rotation speed can be reduced and the noise can be reduced. Further, if R1 ≦ R3, it is necessary to cut out a part of the contact surface 5C to provide a fuel flow path, which may cause a large axis deviation, but in the first embodiment, there is no such concern.

  Further, the stator 19 and the housing 4 are only in contact with each other at the crimped portions 4A and 28B, and there are no other contact points. That is, even if the stator 19 is press-fitted into the pump base 5 that is press-fitted and fixed in the housing 4, there is no place where the stator 19 and the housing 4 interfere with each other. Therefore, during assembly, it is possible to prevent the stator 19 and the housing 4 from interfering with each other and deforming the components.

  Further, on the axial end surface of the housing 4, the caulking portion 4A is inclined toward the inner diameter side with respect to the outer diameter of the housing 4, so that the stator mold 23 and the housing 4 are brought into contact with each other at the caulking portion 28B. As a result, the surface pressure can be applied to the stator mold 23 and the crimped portions 4A and 28B of the housing 4, which improves the adhesion, and thus prevents the fuel from leaking from the motor portion 2 to the outside. it can. Furthermore, the load at the time of producing the caulked portions 4A and 28B is received by the support surfaces 5D and 5G. At this time, the stator core 21 and the pump base 5, which are metallic materials having high rigidity, can be received, and thereby caulking can be performed with a strong force, so that the adhesion of the caulking portions 4A and 28B can be improved. Therefore, it is possible to prevent the fuel from leaking to the outside from the motor unit 2.

Embodiment 2.
FIG. 8 shows a sectional view of the fuel pump 1 according to the second embodiment. In the second embodiment, the pump base 5 and the stator 19 of the first embodiment are different from each other in a point of contact with each other, and the material of a part of the stator 19 in contact with is different. A stator mold 23 is formed on the entire stator 19 of the second embodiment. Along with this, the pump base 5 is downsized, and the axial dimension of the second embodiment is shorter than that of the first embodiment.

  A downward cylindrical protrusion 23B is provided at the lower end of the stator mold 23 in the axial direction on the pump portion 3 side, and the end surface 23C abuts the upper surface 5N of the pump base 5. The outer diameter contact surface 23D of the downward cylindrical protrusion 23B contacts the contact surface 5C of the pump base 5. Others are the same as those in the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 8, the outer diameter contact surface 23D of the downward cylindrical protrusion 23B of the resin-molded stator mold 23 that covers the insulator 26 and the coil 22 assembled in the stator core 21 and the bearing portion 25 are coaxially raised. It is processed to precision. Further, the end surface 23C of the downward cylindrical protruding portion 23B is also processed to have flatness. In the second embodiment, since the stator mold 23 covers the entire length of the stator core 21, the fuel passing through the gap between the rotor 20 and the stator 19 passes through the laminated gap from the inner diameter of the stator core 21 toward the outer diameter. It is possible to suppress the exudation and contribute to the high efficiency of the fuel pump 1.

  The stator 19 and the pump base 5 are assembled by pressing the outer diameter contact surface 23D of the downward cylindrical protrusion 23B and the contact surface 5C of the pump base 5 into contact with each other. Further, the end surface 23C of the downward cylindrical protruding portion 23B and the upper surface 5N of the pump base 5 are brought into contact with each other to perform axial positioning of both.

  By doing so, the following effects can be obtained. The contact surface 5C of the pump base 5 and the outer diameter contact surface 23D of the downward cylindrical projection 23B of the stator mold 23 were brought into contact with each other. Therefore, the contact portion can be arranged at a position where the passage loss is reduced with respect to the passage hole 13 through which the fuel flows from the pump portion 3 to the motor portion 2. For example, when the outer diameter of the stator core 21 is used as the contact surface 5C as in the first embodiment, the outer diameter of the stator core 21 = the outer diameter of the contact surface 5C is determined.

  Since the size of the stator core 21 is generally the minimum size, if the stator core 21 is shaved to optimize the position of the passage hole 13, there is a concern that magnetic saturation may be caused and efficiency may be reduced. In the configuration of the second embodiment, the axial dimension of the pump base 5 can be shortened as compared with the first embodiment, the amount of material used for the pump base 5 can be reduced, and the axial length of the fuel pump 1 can be shortened. be able to. When the axial length of the pump base 5 of the first embodiment is L1 and the axial length of the pump base 5 of the second embodiment is L2, L1> L2, for example, L1 = 124 mm, L2 = 91 mm, The axial length is about 0.73 times.

  Further, the stator mold 23 covers the entire length of the stator core 21. By doing so, even if the fuel passing through the gap exudes from the inner diameter of the stator core 21 toward the outer diameter, it can be sealed by the stator mold 23 and the fuel leaking to the outside of the fuel pump 1 can be further suppressed, and the fuel pump 1 Can contribute to higher efficiency.

Embodiment 3.
Next, FIG. 9 shows a cross-sectional view of the fuel pump 1 according to the third embodiment. In the third embodiment, the contact portions between the stator 19 and the pump base 5 of the second embodiment described above are different. In the third embodiment, as shown in FIG. 9, the contact surface 26B of the insulator 26 provided on the outer wall 26A located at the lower portion in the axial direction of the insulator 26 and the inner upward cylindrical protrusion 5H of the pump base 5 are disposed. It contacts with the outer peripheral surface 5J provided on the.

  That is, as shown in FIG. 7, 12 insulators 26 are arranged in the circumferential direction, and 12 outer walls 26A are also present. The pump base 5 is provided with an inner upward cylindrical protrusion 5H, and the outer peripheral surface 5J of the outer periphery thereof is in contact with the contact surface 26B of the insulator 26. Further, the stator mold 23 has a lower end surface 23E, and an outer wall 26A of the insulator 26 projects from the lower end surface 23E toward the pump base 5 side. The rest of the configuration is the same as that of the second embodiment described above, so the description thereof is omitted.

  In the manufacturing method of the fuel pump 1 having this configuration, the insulator 26 is attached to the stator core 21, resin molding is performed so as to cover the whole of the coil 22 after the winding is completed, the stator mold 23 is manufactured, and the stator mold 23 is projected downward in the axial direction. The outer wall 26A and the bearing insertion surface 25C of the bearing portion 25 are cut so that the contact surface 26B is formed on the insulator 26. At this time, the inner diameter of the stator core 21 and the bearing insertion surface 25C are machined coaxially. Since the stator mold 23 covers the entire length of the stator core 21, it is possible to prevent the fuel passing through the gap from seeping out toward the outer diameter of the stator core 21, which contributes to improving the efficiency of the fuel pump 1.

  The stator 19 and the pump base 5 are assembled by abutting the contact surface 26B of the insulator 26 and the outer peripheral surface 5J of the pump base 5. In the third embodiment, assembly is performed by fitting in a gap. Further, the lower end surface 23E of the stator mold 23 and the upper surface 5K of the inner upward cylindrical protrusion 5H of the pump base 5 are brought into contact with each other to perform axial positioning.

  By doing so, the following effects can be obtained. An outer wall 26A of the insulator 26 is axially extended from a lower end surface 23E of the stator mold 23 to form a contact surface 26B. As a result, the axial dimension can be shortened and the amount of material used can be suppressed.

Fourth Embodiment
FIG. 10 shows a sectional view of the fuel pump 1 according to the fourth embodiment. In the third embodiment described above, the contact surfaces 26B provided on the outer walls 26A of the twelve insulators 26, which is equal to the total number of the coils 22 provided on the stator core 21, are brought into contact with the outer peripheral surface 5J of the pump base 5. However, in the fourth embodiment, among the twelve insulators 26, a predetermined number, for example, the first, third, fifth, etc., and six inner side walls 26F of every other insulator 26 are illustrated. As shown on the right side of 10, a contact surface 26D of the insulator 26 is provided at a position of a radius R4 so as to project axially downward from a lower end surface 23E of the stator mold 23. The inner side wall 26F does not project on the left side of FIG. For example, the second insulator 26 is shown.

  The pump base 5 is formed with a groove 5L that forms a circle. The outer peripheral surface 5M of the groove 5L is in contact with the contact surface 26D of the insulator 26, and the upper surface 5K of the pump base 5 is stator-molded. The lower end surface 23E of 23 abuts. Further, the pump base 5 is provided with a through hole 13 outside the groove 5L. Here, the distance R3 of the outer edge of the communication hole 13 ≧ the radius R4 of the contact surface 26D. The common hole 13 is located, for example, at a position of the 12 insulators 26 where the second insulator 26 is provided. That is, the through hole 13 is provided at a position inside the insulator 26 where the inner wall 26F of the insulator 26 does not project axially downward from the stator mold 23.

  By adopting such a configuration, there are no obstacles that cause a pressure loss of fuel in the gap between the passage hole 13 that is a fuel flow path and the rotor 20 and the stator 19, and the impeller 6 There is no need to make the outer diameter smaller than the inner wall 26F of the insulator 26, more fuel can be boosted at the same number of revolutions, the coaxiality between the two bearings can be maintained, and the high efficiency of the fuel pump 1 can be achieved. Can be realized.

  In the present invention, the respective embodiments can be freely combined, or the respective embodiments can be appropriately modified or omitted within the scope of the invention.

1 fuel pump, 2 motor part, 3 pump part, 4 housing,
4A, 4B caulking portion, 5 pump base, 5A downward cylindrical protruding portion,
5B upward cylindrical protrusion, 5C contact surface, 5D support surface, 5E circumferential contact surface, 5F contact surface, 5G support surface, 5H inner upward cylinder projection, 7 pump cover, 12C bearing insertion surface,
13 general purpose holes, 19 stators, 20 rotors, 21 stator cores,
21A lower end outer peripheral surface, 21B lower end surface, 23 stator mold, 23D outer diameter contact surface, 26 insulator, 26A outer side wall, 26B contact surface, 27 rotating shaft,
28A, 28B crimped portion, outer radius of R1 stator core,
R2 Inner radius of stator core, R3 distance.

Claims (7)

A fuel pump that sucks fuel, boosts the pressure, and discharges the fuel to the outside. The fuel pump has a rotating shaft common to the pump unit, drives the impeller of the pump unit, and includes a coil and a stator core located above the pump unit. and a motor unit having a stator, a pump base of the pump portion is a bearing portion is provided for supporting the rotary shaft, the stator of the motor unit is located on the pump side of the motor unit A resin-made stator mold that covers the entire stator is provided such that an outer wall of an insulator that houses the coil projects toward the pump, and a bearing portion that supports the rotating shaft is provided on the stator mold. When the a discharge port is provided in the fuel, the stator has an inner abutment surface of the outer wall of said insulator is provided on the pump base Together contacts the outer peripheral surface of the counter cylinder protrusions, the and the lower end surface of the stator mold is supported by contact with the upper surface of the inner upward cylindrical projection portion, wherein the motor unit and the cylindrical housing the pump unit Is provided in contact with an outer diameter portion of the pump base, and the housing is abutted by a circumferential contact surface of the pump base and is supported by a support surface of the pump base, and the housing is the pump portion. 2. A fuel pump comprising a caulking portion of a pump cover provided with the fuel suction port, and a caulking portion of an upper portion of the stator mold. The bearing insertion surface of the bearing portion of the stator mold together are made form the outer diameter coaxial with the stator core, the bearing insertion surface of the bearing portion of the pump base also forms the contact surface coaxial with the pump base The fuel pump according to claim 1, wherein the fuel pump is formed. An inner radius R2 of the stator core and the outer radius R1 of the stator core, the Spoken hole so that the relationship between the distance R3 between the outer edge and the axial center of the generic hole of the fuel provided to the pump base and R1 ≧ R3> R2 3. The fuel pump according to claim 1 or 2, wherein the position is set. The outer peripheral surface of the pump base of the inner upward cylindrical projection portion, and the abutment surface of the outer wall of said insulator, claims are made form the bearing insertion face the same axial center of the bearing portion of the pump base 1. The fuel pump according to 1 . A fuel pump that sucks fuel, boosts the pressure, and discharges the fuel to the outside. The fuel pump has a rotating shaft common to the pump unit, drives the impeller of the pump unit, and includes a coil and a stator core located above the pump unit. and a motor unit having a stator, a pump base of the pump portion is a bearing portion is provided for supporting the rotary shaft, the stator of the motor unit is located on the pump side of the motor unit A resin-made stator mold that covers the entire stator is provided such that the inner walls of a predetermined number of insulators that house the coils project toward the pump, and the rotating shaft is provided above the stator mold. a bearing portion for supporting has a discharge port is provided in the fuel, the stator contact surface of the inner wall of the insulator is provided on the pump base Together contacts the outer peripheral surface of the groove, the lower end surface of the stator mold is supported by contact with the upper surface of the upward cylindrical protrusion provided on the pump base, a cylindrical housing the pump unit Is provided in contact with the motor portion at an outer diameter portion, the housing is abutted on a circumferential contact surface of the pump base, and is supported on a support surface of the pump base, and the housing is A fuel pump including a caulking portion of a pump cover provided with the fuel suction port of the pump portion and a caulking portion of an upper portion of the stator mold. The outer peripheral surface and the inner wall of the insulator is, the fuel pump according to the bearing insert surface and claim 5, which is made form the same shaft center of the bearing portion of the pump base of the pump base of the groove. The relationship between the distance R3 of the fuel passage hole provided in the pump base and the radius R4 of the inner wall of the insulator is R3> R4, and the passage hole faces a portion where the inner wall of the insulator does not project. The fuel pump according to claim 6 , wherein the fuel pump is provided.

Images