JP4687491B2 - Motor and fuel pump using the same - Google Patents

Description

  The present invention relates to an inner rotor type brushless motor and a fuel pump using the same.

  Conventionally, a fuel pump using an inner rotor type brushless motor as a drive source is known (see, for example, Patent Documents 1 and 2). The brushless motor has a sliding resistance between the commutator and the brush like the brush motor, an electric resistance between the commutator and the brush, and a fluid resistance received by a groove provided to divide the commutator into each segment. There is no loss problem. As a result, the motor efficiency of the brushless motor is higher than that of the brush motor, and as a result, the efficiency of the fuel pump is improved. Here, the fuel pump efficiency is expressed by (motor efficiency) × (pump efficiency). Motor efficiency and pump efficiency are: I for drive current supplied to the motor of the fuel pump, V for applied voltage, T for motor torque, N for motor rotation speed, P for fuel pressure discharged by the fuel pump, and fuel discharge. When the quantity is Q, (motor efficiency) = (T × N) / (I × V), (pump efficiency) = (P × Q) / (T × N). That is, (fuel pump efficiency) = (motor efficiency) × (pump efficiency) = (P × Q) / (I × V).

And if it is equivalent motor efficiency, since a motor can be reduced in size rather than using a brush motor, the fuel pump using a brushless motor can be reduced in size.
The inventor of the present application, in such an inner rotor type brushless motor, by forming a stator core that surrounds the outer periphery of the rotor with a plurality of coil cores installed in the circumferential direction, a limited winding of each coil core with the miniaturization of the motor. We are studying a structure that easily winds a coil winding in a space with a high space factor. Here, the space factor is the ratio of the cross-sectional area of the winding occupying the winding space. That is, when the space factor is high, the number of windings that can be wound in the winding space increases, so that the motor efficiency can be improved while miniaturizing the motor.

  In the meantime, in the coil core 300 having the shape shown in FIG. 4 constituting the stator core, the inner peripheral surface 305 of the outer peripheral core 304 extending in the circumferential direction on the radially outer side of the teeth 302 is a flat surface, and both ends of the inner peripheral surface 305 in the circumferential direction. A virtual straight line 330 connecting the two is located on the inner peripheral surface 305. A coil winding surface 312 on the outer peripheral core 304 side of the insulator 310 around which the coil 320 is wound is a plane along the virtual straight line 330. Thus, when the coil winding surface 312 on the outer peripheral core 304 side of the insulator 310 is a plane along the virtual straight line 330, the winding can be easily wound from the opening side of the insulator 310 into the winding space of the insulator 310. .

  However, with the miniaturization of the motor, when the winding is wound a predetermined number of times in a limited winding space, the coil 320 reaches the vicinity of the opening of the insulator 310 and the coils adjacent in the circumferential direction approach or come into contact with each other. There is a risk of causing insulation failure between each other. In order to improve the motor efficiency, it is conceivable to increase the number of windings. However, for this purpose, a larger winding space is required. Therefore, it is required to increase the winding space of the winding while reducing the size of the motor.

JP 2005-110477 A JP 2005-110478 A

  The present invention has been made to solve the above problems, and an object thereof is to provide a motor that increases the winding space while reducing the size of the motor, and a fuel pump using the motor.

According to the first aspect of the present invention, the inner peripheral side of the inner peripheral surface of the outer peripheral core on both sides in the peripheral direction is directed toward the coil core adjacent in the peripheral direction with respect to a virtual straight line connecting both ends of the inner peripheral surface in the peripheral direction. It is inclined to. In the invention described in claim 4, the teeth-side inner peripheral surface of the outer peripheral core is recessed radially outward. In the first and fourth aspects of the invention, the insulator covering the coil core has an outer casing extending from the outer core side of the portion covering the teeth toward both ends in the circumferential direction of the inner peripheral surface of the outer core. The outer casing of the insulator is provided in a recess formed on the inner peripheral surface of the outer peripheral core on the teeth side, and the coil winding surface which is the radially inner side surface of the outer casing is along a virtual straight line.
According to this structure, the coil winding surface by the side of the outer periphery core of the insulator which covers a coil core is installed in the radial direction outer side as much as possible, and the winding space which an insulator forms can be increased. Moreover, since the clearance gap between the coils adjacent to the circumferential direction will become large if it is the same number of turns, the insulation failure of the coils adjacent to the circumferential direction can be prevented. Further, since the winding space is increased, the number of winding turns can be increased while preventing the adjacent coils in the circumferential direction from being too close to each other, so that the motor efficiency is improved.

Particularly, in the invention described in claim 2, since the virtual straight line is located on the coil winding surface on the outer peripheral core side of the insulator, the opening position on the outer peripheral core side of the coil core and the opening position on the outer peripheral core side of the insulator Match. Therefore, the winding can be easily wound along the coil winding surface on the outer peripheral core side of the insulator from the opening on the outer peripheral core side of the coil core.
In the invention according to claim 5, since the motor according to claims 1 to 4 is used, the fuel pump can be reduced in size.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fuel pump using a motor according to an embodiment of the present invention is shown in FIG. The fuel pump 10 of the present embodiment is an in-tank type turbine pump installed in a fuel tank of a two-wheeled vehicle having a displacement of 150 cc or less, for example.
The fuel pump 10 includes a pump 12 and a motor 14 that rotationally drives the pump 12. The housing of the fuel pump 10 is composed of housings 16 and 18. The housings 16 and 18 are each formed in a cylindrical shape by pressing a metal thin plate, and the housing 18 is press-fitted and fixed in the housing 16. The housing 16 also serves as a housing for the pump 12 and the motor 14 and has a thickness of about 0.5 mm. The pump case 20 and the stator core 30 are caulked and fixed at both axial ends of the housing 16. The pump case 22 and the stator core 30 are axially positioned by being abutted against both ends of the housing 18 in the axial direction.

  The pump 12 is a turbine pump having pump cases 20 and 22 and an impeller 24. The pump case 22 is press-fitted into the housing 16 and abuts against the housing 18 in the axial direction. The pump cases 20 and 22 are pump cases that rotatably accommodate an impeller 24 as a rotating member. C-shaped pump passages 202 are formed between the pump cases 20 and 22 and the impeller 24, respectively. The fuel sucked from the suction port 200 provided in the pump case 20 is pressurized in the pump passage 202 by the rotation of the impeller 24 and is pumped to the motor 14 side. The fuel pumped to the motor 14 side passes through the fuel passage 204 between the stator core 30 and the rotor 60 and is supplied from the discharge port 206 to the engine side.

  The motor 14 is an inner rotor type so-called brushless motor. The motor 14 has a stator core 30, an insulator 40, and a coil 48. As shown in FIG. 1, the stator core 30 is composed of six coil cores 32 that are installed separately at equal intervals in the circumferential direction. The coil core 32 is formed by caulking magnetic steel plates laminated in the axial direction.

  The coil core 32 includes a tooth 34 extending in the radial direction and an outer core 36 extending on both sides in the circumferential direction on the radially outer side of the tooth 34. The outer peripheral surface of the outer peripheral core 36 is formed in an arc shape, and the outer peripheral core 36 of the six coil cores 32 forms an outer peripheral portion of the stator core 30 in an annular shape with almost no gap. With respect to the virtual straight line 100 connecting the circumferential ends of the inner circumferential surface 37 of the outer circumferential core 36, both circumferential sides of the inner circumferential surface 37 are inclined radially inward toward the coil core 32 adjacent in the circumferential direction. Yes. The teeth 34 side of the inner peripheral surface 37 of the outer peripheral core 36 is a plane along the virtual straight line 100. That is, the teeth 34 side of the inner peripheral surface 37 of the outer peripheral core 36 is located on the radially outer side than the virtual straight line 100 and is recessed. The teeth 34 side of the outer core 36 is thicker than both sides of the outer core 36 in the circumferential direction, and this thick portion is an unnecessary portion for the magnetic circuit. Therefore, even if the teeth 34 side of the inner peripheral surface 37 of the outer core 36 is recessed radially outward from the virtual straight line 100, the magnetic performance does not deteriorate. In the present embodiment, when the inner circumferential surfaces 37 on both circumferential sides of the outer circumferential core 36 are inclined inward in the radial direction with respect to the imaginary straight line 100 toward the coil core 32 adjacent in the circumferential direction, α in this embodiment. 25 ° ≦ α ≦ 35 °.

  The pair of insulators 40 are formed in substantially the same shape, and are fitted to the coil cores 32 by being fitted to the coil cores 32 from both ends in the axial direction. The insulator 40 has an inner flange 42 on the radially inner side and an outer flange 44 on the radially outer side, and forms a winding space between the inner flange 42 and the outer flange 44. The coil 48 is formed by winding a winding in this winding space. The outer casing 44 is provided in a plane portion where the inner peripheral surface 37 of the outer peripheral core 36 is recessed radially outward with respect to the virtual straight line 100. The coil winding surface 46 that is the radially inner side surface of the outer casing 44 is a plane along the virtual straight line 100, and the virtual straight line 100 is located on the coil winding surface 46. That is, the opening position of the outer peripheral core 36 and the opening position of the outer collar 44 of the insulator 40 are substantially coincident. Therefore, the winding can be easily wound along the coil winding surface 46 of the outer casing 44 from the opening on the outer peripheral core 36 side of the coil core 32. The coil 48 is formed by concentrically winding the windings around the insulator 40 for each coil core 32.

  As shown in FIG. 2, the insulating resin material 50 covers the stator core 30, the insulator 40, and the coil 48 except for the radially inner circumferential surface and the radially outer circumferential surface of the stator core 30. The end cover 52 is integrally molded with the insulating resin material 50 and forms a discharge port 206. The terminal 56 exposed from the end cover 52 and insert-molded is electrically connected to the coil 48.

The rotor 60 includes a shaft 62 and a permanent magnet 64, and is rotatably installed on the inner periphery of the stator core 30. Both ends of the shaft 62 are rotatably supported by the bearing 26. The permanent magnet 64 is a plastic magnet formed into a cylindrical shape by kneading magnetic powder into a thermoplastic resin material such as PPS (polyphenylene sulfide) or POM (polyacetal). The permanent magnet 64 forms eight magnetic pole portions 65 in the rotation direction. The eight magnetic pole portions 65 are magnetized so as to form different magnetic poles alternately in the rotational direction on the outer peripheral surface facing the coil core 32.
The rotor 60 having the magnetized permanent magnet 64 is switched by a control device (not shown) to energize the coils 48 wound around the coil cores 32, and the inner peripheral side of the coil cores 32 constituting the stator core 30. The rotor 60 is rotated by sequentially switching the magnetic poles generated in the circumferential direction in the circumferential direction.

Next, the winding process for forming the coil 48 will be described.
(1) First, the coil core 32 is formed by caulking magnetic steel plates laminated in the axial direction.
(2) The insulators 40 are fitted and attached to the coil cores 32 from both axial ends of the coil cores 32, respectively. In this state, the opening position of the outer peripheral core 36 and the opening position of the outer flange 44 of the insulator 40 are substantially coincident.
(3) The coil core 32 to which the insulator 40 is attached is placed on the base 122 of the winding device 120 shown in FIG. The mounting surface 124 of the base 122 on which the coil core 32 is mounted is a concave arc surface that matches the convex arc surface of the outer peripheral surface of the outer core 36. Guides 130 and 134 are respectively fixed with bolts or the like on both sides of the base 122 along the axial direction of the coil core 32 and on both ends in the axial direction. The guide surface 132 at the upper end of the guide 130 extends linearly in the axial direction of the coil core 32 and is formed in a smooth convex curved shape with respect to the winding 142 in order to guide the winding 142. The guide surface 136 at the upper end of the guide 134 has a linear shape substantially along the coil winding surface 46 of the outer casing 44 of the insulator 40. Further, the guide surface 136 is formed in a smooth convex curved shape with respect to the winding 142 in order to guide the winding 142.

(4) After the coil core 32 to which the insulator 40 is attached is placed on the base 122, the nozzle 140 that supplies the winding 142 is brought closer to the coil core 32.
(5) Then, as shown in FIG. 3A, the nozzle 140 is moved in the axial direction of the coil core 32 while applying tension to the winding 142 to contact the guide surface 132 at the upper end of the guide 130. When the nozzle 140 reaches the axial end of the coil core 32, the winding 142 moves from the guide surface 132 of the guide 130 to the guide surface 136 of the guide 134. Then, the winding 142 is wound while tension is applied to the winding 142 to contact the guide surface 136 at the upper end of the guide 134.
In this way, the winding 142 is concentrated and wound around the insulator 40 attached to each coil core 32.

  In the embodiment described above, both sides in the circumferential direction of the inner circumferential surface 37 of the outer circumferential core 36 are inclined radially inward with respect to the virtual straight line 100 in the direction toward the coil core 32 adjacent in the circumferential direction. That is, the teeth 34 side of the inner peripheral surface 37 of the outer peripheral core 36 is recessed radially outward from the virtual straight line 100. Therefore, since the coil winding surface 46 on the outer peripheral core 36 side of the insulator 40 covering the coil core 32 can be installed on the radially outer side as much as possible, the winding space formed by the insulator 40 can be reduced while miniaturizing the motor 14 of the fuel pump 10. Can be increased. Therefore, if the number of turns is the same, both circumferential positions of the coils 48 wound around the coil cores 32 can be recessed toward the teeth 34. As a result, the gap 110 between the coils 48 adjacent in the circumferential direction becomes large as shown in FIG. 1, so that poor insulation between the coils 48 adjacent in the circumferential direction can be prevented. Further, since the winding space is increased, the number of windings can be increased while preventing the coils 48 adjacent in the circumferential direction from being too close to each other, so that the motor efficiency is improved.

(Other embodiments)
In the above embodiment, when the stator core 30 is formed by the six coil cores 32, the inclination angle α at which both circumferential sides of the inner peripheral surface 37 of the outer peripheral core 36 are inclined with respect to the virtual straight line 100 is 25 ° ≦ α ≦ 35. Set to °. The inclination angle α decreases as the number of coil cores forming the stator core increases and the circumferential length of the outer core decreases, and increases as the number of coil cores decreases and the circumferential length of the outer core increases. For example, when the number of coil cores is 4, 40 ° ≦ α ≦ 50 ° is set, and when the number of coil cores is 8, 17.5 ° ≦ α ≦ 27.52 °.

In addition, the magnitude | size of inclination-angle (alpha) is not restricted to said range, The coil core with which the internal peripheral surface of the circumferential direction both sides of an outer periphery core adjoins the circumferential direction with respect to the virtual straight line which connects the circumferential direction both ends of the outer peripheral core. As long as it is inclined inward in the radial direction as it goes to, any size may be used.
Also, in order to increase the winding space of the coil while reducing the size of the motor, the inner peripheral surfaces on both sides in the circumferential direction of the outer peripheral core are in the circumferential direction with respect to a virtual straight line connecting both ends in the circumferential direction of the inner peripheral surface of the outer peripheral core. It is not necessary to incline radially inward toward the adjacent coil core, and the inner peripheral surface on the teeth side of the outer peripheral core is radially outer with respect to a virtual straight line connecting both ends of the inner peripheral surface of the outer peripheral core in the circumferential direction. The structure may be recessed.

Moreover, in the said embodiment, although the motor of this invention was applied to the fuel pump, you may use the motor of this invention not only as a fuel pump but as a drive source of another apparatus.
In the above embodiment, the coils 48 are formed by aligning the windings. However, the coils may be formed by randomly winding the windings.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

(A) is sectional drawing which shows the coil core and insulator by this embodiment, (B) is the figure which looked at the motor except a rotor from one axial end side. Sectional drawing which shows the fuel pump by this embodiment. (A) is explanatory drawing which shows the winding process of a coil, (B) is the fragmentary sectional view which looked at (A) from the B direction. Sectional drawing which shows the conventional coil core and insulator.

Explanation of symbols

10: Fuel pump, 12: Pump, 14: Motor, 30: Stator core, 32: Coil core, 34: Teeth, 36: Outer core, 37: Inner circumferential surface, 40: Insulator, 46: Coil winding surface, 48: Coil , 60: rotor, 64: permanent magnet, 100: virtual straight line

Claims (5)

A plurality of coil cores having a tooth extending in the radial direction and an outer peripheral core extending in the circumferential direction on the radially outer side of the tooth in the circumferential direction, with respect to a virtual straight line connecting the circumferential ends of the inner peripheral surface of the outer core, A stator core that is inclined radially inward as the inner peripheral surfaces on both sides in the circumferential direction of the outer core move toward the coil core adjacent in the circumferential direction;
A cormorants insulator covering the coil core, the insulator having an outer flange extending from the outer peripheral core side of the portion covering the teeth in the circumferential direction at both ends of the inner peripheral surface of the outer peripheral core,
A coil wound around the insulator;
The rotatably installed on the inner circumferential side of the stator core, the alternately different magnetic poles in the rotational direction and a rotor which is formed on the outer peripheral surface facing said stator core,
The outer flange of the insulator is provided in a recess formed on an inner peripheral surface of the outer peripheral core on the teeth side, and a coil winding surface that is a radially inner side surface of the outer flange is along the virtual line. A motor characterized by that .   The motor according to claim 1, wherein the virtual straight line is located on the coil winding surface on the outer peripheral core side.   When the inner circumferential surface on both sides in the circumferential direction of the outer peripheral core is inclined radially inward with respect to the virtual straight line as it goes toward the coil core adjacent in the circumferential direction, four coil cores are assumed. In the case of the above, 40 ° ≦ α ≦ 50 °, 25 ° ≦ α ≦ 35 ° when the number of the coil cores is 6, and 17.5 ° ≦ α ≦ 27.5 ° when the number of the coil cores is 8. The motor according to 1 or 2. A plurality of coil cores having a tooth extending in the radial direction and an outer peripheral core extending in the circumferential direction on the radially outer side of the tooth in the circumferential direction, with respect to a virtual straight line connecting the circumferential ends of the inner peripheral surface of the outer core, A stator core in which an inner peripheral surface on the teeth side of the outer peripheral core is recessed radially outward;
A cormorants insulator covering the coil core, the insulator having an outer flange extending from the outer peripheral core side of the portion covering the teeth in the circumferential direction at both ends of the inner peripheral surface of the outer peripheral core,
A coil wound around the insulator;
The rotatably installed on the inner circumferential side of the stator core, the alternately different magnetic poles in the rotational direction and a rotor which is formed on the outer peripheral surface facing said stator core,
The outer flange of the insulator is provided in a recess formed on an inner peripheral surface of the outer peripheral core on the teeth side, and a coil winding surface that is a radially inner side surface of the outer flange is along the virtual line. A motor characterized by that . The motor according to any one of claims 1 to 4,
A pump driven by the motor for sucking and boosting fuel;
A fuel pump comprising.

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