JP2010115019A - Pump motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump motor reducing a flow path resistance of a liquid flow path while securing the flow path of a liquid. <P>SOLUTION: An annular liquid flow path for transferring a liquid is formed so as to extend in an axial direction between a stator and a rotor. An expansion portion for expanding an area of the liquid flow path by expanding a distance between the expanding portion and the rotor is formed on an umbrella portion of teeth. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pump motor that transports liquid.

  Conventionally, pumps for transporting liquids are known, and motors are widely used as drive sources for the pumps.

Patent Document 1 discloses a DC brushless motor applied to a compressor or the like. This motor mainly includes a stator (stator) fixed to the inner wall of the casing and a rotor (rotor) penetrating the stator. In the stator, a stator core is configured by laminating electromagnetic steel sheets. The stator core has an annular yoke and a plurality of teeth arranged in the circumferential direction inside the yoke. Windings are wound around the plurality of teeth via insulators or the like. Moreover, the umbrella part is formed in the front-end | tip of several teeth so that the width | variety of this teeth may be expanded on the both sides of the circumferential direction. The front end surface on the radially inner side of each umbrella portion has an arc shape along the outer peripheral surface of the cylindrical rotor. Thus, a perfect annular gap (gap) is formed between the outer peripheral surface of the rotor and the end surface on the inner diameter side of the umbrella portion of the teeth so that the radial spacing is uniform.
JP 2003-255952 A

  As described above, in a pump motor, a liquid flow path for transporting liquid is generally formed inside a motor casing. However, in the pump motor, there may be a case where a sufficient space for forming the liquid flow path cannot be secured due to the layout restrictions of the respective components such as the stator and the rotor. Thus, for example, it is conceivable to use a gap (gap) between the stator and the rotor disclosed in Patent Document 1 as the liquid flow path. Thereby, an annular liquid flow path extending in the axial direction can be secured inside the pump motor.

  However, only a slight gap is formed between the stator and the rotor so that they do not slide. For this reason, in such a liquid flow path, flow path resistance and by extension, the pressure loss of a liquid increase, and the problem that a pump efficiency falls will arise.

  An object of the present invention is to provide a pump motor that can reduce the flow resistance of the liquid flow path while securing the flow path of the liquid.

  A first invention includes a stator having a plurality of teeth arranged in a circumferential direction and wound with a winding, and a rotor inserted into the stator so as to face an umbrella portion at the tip of each tooth. , Intended for a pump motor in which a liquid flow path for conveying a liquid is formed in a casing that accommodates the stator and the rotor, and the liquid flow path is provided between the stator and the rotor. An annular gap extending in the direction is formed, and the umbrella portion of the teeth has an opposing portion that increases the distance between the umbrella portion and the rotor so as to increase the flow area of the liquid channel. Is formed.

  In the first invention, an annular liquid flow path is formed between the umbrella portion of the teeth of the stator and the outer peripheral surface of the rotor in the casing. That is, when the pump is driven by the motor, the liquid transported by the pump flows through the liquid flow path between the stator and the rotor. Here, in this invention, the opposing part is formed in the umbrella part of the teeth of a stator, and the flow-path area of the liquid flow path is expanded. Accordingly, the channel resistance of the liquid channel is reduced, and the pressure loss of the liquid is reduced.

  In a second aspect based on the first aspect, the opposing portion is formed on at least one or both of the protruding portions protruding on both sides in the circumferential direction in the umbrella portion of the tooth.

  In the second invention, the opposing portion is formed in the protruding portion of the teeth umbrella portion. As a result, it is possible to prevent a decrease in motor efficiency accompanying an increase in the flow channel area of the liquid flow channel. In other words, in the umbrella portion of the teeth, the degree of contribution to the torque for driving the rotor is higher in the central portion between the projecting portions than in the projecting portions projecting on both sides in the circumferential direction. This is because the magnetic flux is more likely to collect in the central portion of the teeth. For this reason, if an opposing part is formed in the center part of an umbrella part, the distance between this center part and a rotor will become large, and the magnetic flux amount which passes a tooth will fall significantly. On the other hand, in the present invention, since the ratio of contribution to the amount of magnetic flux passing through the teeth is low compared to the central portion (the magnetic flux is less likely to collect), the opposing portion is formed. Even if the distance to the rotor increases, the amount of magnetic flux passing through the teeth does not decrease so much. Therefore, in the present invention, a decrease in motor efficiency accompanying an increase in the flow channel area of the liquid flow channel can be suppressed.

  According to a third aspect, in the second aspect, the distance between the teeth and the rotor increases as the umbrella portion of the teeth moves from the central portion between the two protrusions toward the tip of the protrusion. As described above, the facing portion is formed.

  In 3rd invention, in the umbrella part of teeth, the distance (gap) between a stator and a rotor spreads as it goes to the protrusion part from the center part of the umbrella part. Here, the degree of contribution to the amount of magnetic flux that passes through the teeth for driving the rotor decreases from the central portion of the umbrella portion toward the tip of the protruding portion. That is, the influence of the decrease in the induced voltage accompanying the gap enlargement gradually decreases from the central portion toward the tip of the protruding portion. For this reason, by making it like this invention, the fall of the motor efficiency accompanying the expansion of the flow-path area of a liquid flow path can be suppressed to the minimum.

  In the first invention, in the pump motor, a liquid flow path for transporting the liquid is formed between the stator and the rotor. For this reason, the liquid flow path extending in the axial direction can be secured without being restricted in the layout of each component such as the stator and the rotor. Here, in this invention, the flow-path area of a liquid flow path is expanded by forming an opposing part in the umbrella part of teeth. For this reason, the channel resistance of the liquid channel can be reduced, and the pressure loss of the liquid can be reduced. As a result, a decrease in pump efficiency applied to the pump motor can be prevented.

  Moreover, in 2nd invention, the opposing part is formed in at least one of the protrusion part of the circumferential direction both sides of the umbrella part of teeth. Thereby, the flow path resistance of a liquid can be reduced, without extending the distance between the center part of a teeth umbrella part, and a rotor. If it does in this way, since the magnetic flux amount which passes through a tooth will not fall significantly, while preventing the fall of pump efficiency, the fall of motor efficiency can also be prevented. In particular, in the third aspect of the invention, the distance between the rotor and the rotor is increased from the central portion of the teeth umbrella portion toward the protruding portions on both sides, so that the decrease in the amount of magnetic flux passing through the teeth is minimized. The channel area of the liquid channel can be expanded.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

-Overall configuration-
In FIG. 1, schematic structure of the fuel pump 1 provided with the motor 2 which concerns on embodiment of this invention is shown. The fuel pump 1 is disposed in a fuel tank in which fuel such as gasoline or diesel fuel is stored, and is immersed in the fuel. By sucking and discharging the fuel, the fuel is transported to the engine via the fuel pipe. That is, the motor 2 constitutes a pump motor that transports liquid such as fuel.

  Specifically, the fuel pump 1 is arranged in a substantially cylindrical metal casing 4 so that the motor 2 and the impeller 3 connected to the rotating shaft 22 of the motor 2 are aligned in the axial direction. is there. The end of the casing 4 on the motor 2 side is covered with a resin discharge side lid member 5, while the end of the impeller 3 side is made of a resin that forms a pump chamber S for housing the impeller 3. Covered by a pump casing 11 and a pump cover 12.

  The discharge-side cover member 5 is made of a substantially disk-shaped resin member, and has a discharge port 5a formed so as to penetrate in the thickness direction. A recess 5b is formed in which a bearing 6 for rotatably supporting one end of the rotary shaft 22 is housed. Further, as will be described later, the discharge-side lid member 5 is provided with a bus bar opening 5c so that an external bus bar 36 extending from the stator 31 of the motor 2 to the outside of the pump 1 can be inserted.

  The pump casing 11 and the pump cover 12 that form the pump chamber S are each made of a substantially disk-shaped resin member. The pump casing 11 is on the inner side of the casing 4, and the pump cover 12 is on the outer side of the casing 4. It is arranged to be located. The pump cover 12 is formed with a suction port 12a so as to penetrate in the thickness direction and communicate with the pump chamber S, while the pump casing 11 sucks so as to penetrate in the thickness direction and communicate with the pump chamber S. A passage 11a is formed. Thereby, the inside of the casing 4 communicates with the outside via the suction port 12a, the pump chamber S, and the suction passage 11a.

  The pump casing 11 is formed with a recess 11b that forms the pump chamber S and can accommodate the impeller 3 on the surface of the pump cover 12 (the lower side in FIG. 1), and at a substantially central portion in plan view. A through hole 11c through which the rotating shaft 22 of the motor 2 is inserted is formed. Further, on the inner side of the casing 4 (upper side in FIG. 1) of the through hole 11c, an enlarged hole portion 11d is formed in which the bearing 7 for rotatably supporting the other end side of the rotary shaft 22 is accommodated. Yes.

  The impeller 3 is formed in a propeller shape, for example, and the other end side of the rotating shaft 22 of the motor 2 is connected to a substantially central portion in a plan view. Further, the impeller 3 is formed in a shape that draws fuel into the casing 4 from the suction port 12a when rotated by the motor 2. Accordingly, the rotation of the impeller 3 causes the fuel to be sucked into the pump chamber S via the suction port 12a and flow into the casing 4 of the fuel pump 1 via the suction passage 11a. The fuel sucked into the casing 4 in this way flows inside the motor 2 (between the rotor 21 and the stator 31) and is discharged to the outside from the discharge port 5a formed in the discharge side lid member 5. .

  The motor 2 includes a substantially columnar rotor 21 connected to the impeller 3 by a rotation shaft 22, and a stator 31 formed in a substantially cylindrical shape so as to surround the rotor 21. In this motor 2, a permanent magnet 25 is provided in the rotor 21, and a winding 33 is provided in the stator 31, respectively. By energizing the winding 33 of the stator 31 at a predetermined timing, A so-called brushless motor is configured to control the rotation of the rotor 21.

  The rotor 21 includes a rotating shaft 22 that is rotatably supported at both ends by bearings 6 and 7, and a rotor portion 23 fitted on the rotating shaft 22, and the rotating shaft 22 and the rotor portion 23 are provided. It is configured to rotate integrally. The rotor portion 23 includes a substantially cylindrical rotor core 24 formed by laminating steel plates, and a plurality of permanent magnets 25, 25,... Provided so as to penetrate the rotor core 24 in the longitudinal direction. Specifically, as shown in FIG. 2, the rotor portion 23 is formed with four slots 24a having a rectangular cross section so as to surround the rotating shaft 22, and the permanent magnets 25 are inserted into the slots 24a. .

  As shown in FIG. 1, both end portions in the longitudinal direction of the rotor portion 23 are covered with a resin 26 so that the permanent magnet 25 in the rotor portion 23 does not come out. By covering both ends in the longitudinal direction of the rotor portion 23 with the resin 26, the permanent magnet 25 can be prevented from coming into contact with the fuel passing through the motor 2, and the permanent magnet 25 can be prevented from being rusted. it can. The resin 26 is formed in a substantially hemispherical shape so that the thickness gradually increases toward the rotation center of the rotor portion 23. Thereby, when the fuel passes through the motor 2 in the axial direction, the flow path resistance at the axial end portion of the rotor portion 23 can be reduced, so that the fuel can flow efficiently.

  Further, as shown in FIG. 2, the rotor portion 23 has a through hole as a so-called flux barrier that prevents a magnetic flux from being short-circuited between the permanent magnets 25 between the slots 24 a in which the permanent magnets 25 are accommodated. 24b is provided. Since the through holes 24b are provided so as to penetrate the rotor core 24 in the axial direction, when both ends in the axial direction of the rotor portion 23 are sealed with the resin 26 as described above, the through holes 24b are formed in the through holes 24b. Also, the resin 26 is filled. Thereby, since the resin 26 at both ends in the axial direction of the rotor portion 23 can be integrated by the resin 26 in the through hole 24b, the adhesive strength of the resin 26 to both end portions in the axial direction of the rotor portion 23 is improved. Can do.

  As shown in FIGS. 1 and 2, the stator 31 includes a substantially cylindrical stator core 32 formed by stacking steel plates, and a plurality of windings formed by winding coil wires around the teeth 40 of the stator core 32. 33. Specifically, the stator core 32 includes a substantially annular core back portion 32a and a plurality of teeth 40 (6 in the present embodiment) provided to protrude radially inward on the inner peripheral side thereof. One).

  The plurality of teeth 40 are arranged in the circumferential direction at equal intervals on the outer peripheral side of the rotor 21. The teeth 40 are configured by a teeth base portion 41 around which the winding 33 is wound, and a teeth umbrella portion (so-called umbrella) 42 formed on the radially inner side of the teeth base portion 41. The teeth base 41 has a substantially uniform length in the width direction, and a winding 33 is wound around it.

  The teeth umbrella portion 42 is configured to be wider than the teeth base portion 41. The tip of each teeth umbrella portion 42 faces the rotor portion 23 of the rotor 21. The teeth umbrella portion 42 has two projecting portions 42a and 42a extending from the teeth base portion 41 side to both sides in the circumferential direction (width direction), and a central portion 42b located between the projecting portions 42a and 42a. As described above, the outer shape of each tooth 40 is formed in a T-shaped or Y-shaped cross section perpendicular to the axis. The stator core 32 is formed of a so-called straight core in which a plurality of core portions each having teeth 40 are connected in a strip shape, and is formed into a cylindrical shape by bending the straight core. In FIG. 2, reference numeral 32 d is a joint between the straight cores, and reference numeral 32 e is a bent portion of the straight core.

  The teeth 40 are covered with an insulating member 34 from the radially outer peripheral side of the tooth umbrella portion 42 to the inner peripheral side of the core back portion 32 a, and a coil wire is wound on the insulating member 34. Each of the windings 33 formed by winding a coil wire around the teeth 40 is connected to a copper bus bar 35 so as to be in a U phase, a V phase, and a W phase when energized, and the copper wire connected to the bus bar 35 is made of copper. A control circuit (not shown) is connected via an external bus bar 36. In addition, the coil 33 of the windings 33 and 33 is connected so that the winding 33 may be in the same phase when the windings 33 and 33 at positions opposed to each other by 180 degrees are energized.

  Similar to the rotor 21, both end portions in the axial direction of the stator 31 are covered with the resin 37. That is, the insulating member 34, the winding 33, and the bus bars 35 and 36 are sealed with the resin 37 at both axial ends of the stator 31. Moreover, since the space penetrated in the axial direction is formed between teeth 40 and 40, resin 37 is filled also in these spaces. Thus, by sealing both ends in the axial direction of the stator 31 with the resin 37, when the fuel flows in the motor 2, the surface of the surface is connected to connect to the copper bus bars 35, 36 and the bus bars 35, 36. Since the coil wire from which a part of the coating is removed, the steel plate of the stator core 32 and the like can be prevented from coming into contact with the fuel, it is possible to reliably prevent these parts from being rusted by the fuel. Moreover, since the space between the teeth 40 of the stator core 32 is also sealed with the resin 37, the coil wire and the steel plate of the stator core 32 can be reliably prevented from coming into contact with the fuel. .

  An annular gap (gap G) is formed between the teeth 40 of the stator 31 and the rotor 21. Due to the gap G, the rotor 21 is allowed to rotate without being in sliding contact with the stator 31. Further, the gap G constitutes a liquid flow path 50 for transporting fuel. The liquid channel 50 has an axially perpendicular cross section formed in an annular shape and extends in the axial direction. The opening on the lower end side of the liquid flow path 50 communicates with the suction passage 11a, and the opening on the upper end side of the liquid flow path 50 communicates with the discharge passage in the discharge port 5a. Thus, when the impeller 3 rotates, the fuel that has flowed out of the suction passage 11a flows upward through the liquid flow path 50, and then flows out of the discharge pipe 5a and is supplied to an external engine or the like.

  The teeth umbrella portion 42 is formed with a facing portion 43 that increases the distance between the rotor 21 and the channel area of the liquid channel 50. That is, in the teeth umbrella portion 42 of the present embodiment, the distance between the rotor 21 is not uniform over the entire area, and the distance between the facing portion 43 and the rotor 21 is greater than that of other parts. It is getting bigger. That is, the facing portion 43 constitutes a flow channel expanding portion that expands the flow channel area of the liquid flow channel 50. Thereby, in the liquid flow path 50, the flow path resistance is reduced or the pressure loss when the fuel is conveyed is reduced.

  In addition, on the radially inner surface (tip surface) of the tooth umbrella portion 42, an opposing portion 43 is formed on the protruding portions 42a and 42a. That is, in the tooth umbrella portion 42, the facing portion 43 is formed so that the distance between the protruding portion 42 a and the rotor 21 is larger than the distance between the center portion 42 b and the rotor 21. Further, in the teeth umbrella portion 42, the facing portion 43 is formed so that the curvature radius of the tip surface thereof is larger than the curvature radius of the outer peripheral surface of the rotor 21. And in the teeth umbrella part 42, the distance between the rotor 21 is expanded as it goes to the front-end | tip of the protrusion part 42a from the center part 42b. In the present embodiment, a slight radius is formed on the tip surface of the tooth umbrella portion 42, but this may be a straight surface.

  By configuring the teeth umbrella portion 42 as described above, a reduction in motor efficiency associated with an increase in the channel area of the liquid channel 50 is prevented. That is, in the tooth umbrella portion 42, the central portion 42 b has a higher degree of contribution to the torque for driving the rotor 21 than the protruding portion 42 a. This is because, in the tooth umbrella portion 42, the magnetic flux is more likely to collect in the central portion 42b than in the protruding portion 42a. For this reason, if the opposing part 43 is formed in the center part 42b of the teeth umbrella part 42, the distance between this center part 42b and the rotor 21 will become large, and the amount of magnetic flux which passes the teeth 40 will fall significantly. . On the other hand, in the present embodiment, the opposing portion 43 is formed in the protruding portion 42a that has a lower ratio of contributing to the amount of magnetic flux passing through the teeth 40 than the central portion 42b (the magnetic flux is less likely to collect). Even if the distance between the portion 42a and the rotor 21 increases, the amount of magnetic flux passing through the teeth 40 does not decrease so much. Therefore, a reduction in motor efficiency associated with an increase in the channel area of the liquid channel 50 is prevented.

-Effect of the embodiment-
In the embodiment, the liquid flow path 50 for transporting the fuel is formed between the stator 31 and the rotor 21. For this reason, the liquid flow path 50 extending in the axial direction can be secured without being restricted in the layout of each component such as the stator 31 and the rotor 21. Here, in this embodiment, the channel area of the liquid channel 50 is expanded by forming the facing portion 43 in the teeth umbrella portion 42. For this reason, the channel resistance of the liquid channel 50 can be reduced, and the pressure loss of the liquid can be reduced. As a result, a decrease in pump efficiency of the fuel pump 1 can be prevented.

  Further, a facing portion 43 is formed on the protruding portion 42 a of the teeth umbrella portion 42. Thereby, the flow path resistance of a liquid can be reduced, without extending the distance between the center part 42b of the teeth umbrella part 42, and the rotor 21. FIG. If it does in this way, since the magnetic flux amount which passes through the teeth 40 will not fall significantly, the fall of motor efficiency can also be prevented. In particular, since the distance from the rotor 21 is increased toward the protrusion 42a from the central portion 42b of the tooth umbrella portion 42, the liquid flow path is minimized while minimizing the decrease in the amount of magnetic flux passing through the teeth 40. 50 channel areas can be expanded.

<Modification of Embodiment>
In the said embodiment, in the teeth umbrella part 42, the opposing part 43 is formed in protrusion part 42a, 42a which protrudes on the both sides of the circumferential direction. However, for example, as shown in FIG. 3, a facing portion 43 may be formed in the central portion 42 b of the teeth umbrella portion 42. That is, in the tooth umbrella portion 42 of this example, the distance between the central portion 42b and the rotor 21 is larger than the distance between the protruding portion 42a and the rotor. Also in this case, since the flow channel area of the liquid flow channel 50 is increased, the flow resistance of the liquid flow channel 50 can be reduced to prevent a decrease in pump efficiency.

  For example, as shown in FIG. 4, the facing portion 43 can be configured by forming an arc groove in the teeth umbrella portion. In this example, the shape of the liquid channel 50 is formed in a substantially circular shape, and the channel area of the liquid channel 50 is expanded by the arc groove 43. As a result, also in this example, the flow resistance of the liquid flow path 50 can be reduced to prevent a decrease in pump efficiency. In addition, the groove | channel for comprising the opposing part 43 may be other shapes, such as triangular shape, square shape, trapezoid shape.

<< Other Embodiments >>
About the said embodiment, it is good also as following structures.

  In the above-described embodiment, a turbine type pump having an impeller made of an impeller 3 is used as a pump mechanism. However, for example, a positive displacement type in which a roller or the like is displaced in a cylindrical cylinder chamber to pump liquid. The pump mechanism may be used. In addition, the pump motor of the above embodiment is applied to a fuel pump intended for transporting fuel, but can also be applied to, for example, a pump that transports water by being immersed in water.

  As described above, the present invention is useful for a motor for a pump that transports a liquid.

FIG. 1 is a longitudinal sectional view showing an overall configuration of a fuel pump according to an embodiment. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view illustrating a schematic configuration of a motor according to a first example of a modification of the embodiment. FIG. 4 is a cross-sectional view illustrating a schematic configuration of a motor according to a second example of the modification of the embodiment.

Explanation of symbols

21 Rotor 31 Stator 40 Teeth 42 Teeth umbrella part (umbrella part)
42a Projecting part 42b Central part 43 Opposing part 50 Liquid flow path

Claims (3)

A stator having a plurality of teeth arranged in a circumferential direction and wound with windings, and a rotor inserted into the stator so as to face the umbrella portion at the tip of each tooth, the stator and the rotation A pump motor in which a liquid flow path for conveying a liquid is formed in a casing that houses a child,
The liquid flow path is constituted by an annular gap extending in the axial direction between the stator and the rotor,
The pump motor is provided with an opposing portion that extends a distance between the umbrella portion and the rotor so as to increase a flow passage area of the liquid flow passage in the umbrella portion of the tooth. The pump motor according to claim 1,
The pump motor in which the opposing part is formed in at least one or both of the protrusion part which protrudes in the circumferential direction both sides of the umbrella part in the umbrella part of the teeth. The pump motor according to claim 2,
A pump in which the facing portion is formed on the umbrella portion of the teeth so that the distance from the rotor increases from the central portion between the two protruding portions toward the tip of the protruding portion. Motor.

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