JP4904251B2 - DC motor for pump - Google Patents

Description

  According to the present invention, the wear speed of the impeller bearing can be reduced, so that the service life of the impeller 3 can be extended, and the stator core has a higher degree of freedom in shape, thereby reducing magnetic leakage and increasing efficiency. The present invention relates to a pump DC motor that can be used.

Conventionally, as an electric water pump for automobiles, a separate electric water pump in which a motor and an impeller drive source are separate has been used. That is, the separate electric water pump is a system (magnet coupling system) in which an outer magnet is rotated by a motor and an impeller containing a magnet magnetically coupled to the outer magnet is rotated. Development and implementation of an integrated electric water pump that directly rotates an impeller with a built-in magnet with the motor's stator core (electromagnet) itself has been started to meet the recent demand for higher efficiency and lighter weight. Patent Document 1 is an example in which such an impeller is incorporated in a motor. The impeller of the electric water pump disclosed in Patent Document 1 is provided with a magnet that generates a magnetic field in one direction.
JP 2002-364576 A

  According to Patent Document 1, a stator core (electromagnet) is provided on the outer periphery of a motor, and an impeller incorporating a magnet as an inner rotor (inner peripheral rotation method) is rotated by a magnetic attractive repulsive force between the stator core and the impeller. Is. The stator core generally has a structure in which a coil wire is wound around a laminated steel plate in which steel plates are overlapped. And if the magnetic field of a stator core is changed in order, the magnet integrated with the impeller will rotate, the impeller integrated with the magnet will also rotate, and will play the role of a pump. A common problem exists in the integrated electric water pump having the above structure.

The first problem is the reduction of the impeller bearing life due to the thrust of the impeller.
The impeller has blades, but when a blade-shaped object is rotated, an upward force is generated. The impeller tends to move in the pump suction direction due to thrust, but since the impeller must rotate at a fixed position, a stopper mechanism is attached. This is indicated by reference numeral 54 in the drawing of Patent Document 1, and 54 serves as a function of fixing the shaft and an axial stopper of the impeller. The position of the impeller in the axial direction is fixed by the presence of the stopper, but a thrust is always generated. Therefore, the stopper end surface and the impeller bearing portion slide while being pressed by the thrust. As a result, the impeller bearing is worn and the bearing life is limited.
As a solution to this problem, it is considered that bearing wear decreases if there is a force that opposes the thrust in the opposite direction.

The second problem is that the shape flexibility of the stator core is low.
<Stator core of laminated steel plate>
If a laminated steel plate formed by stacking steel plates is used as a stator core, a desired three-dimensional shape cannot be obtained, and the shape is restricted. For this reason, the stator core becomes large in order to obtain a large rotor rotational force with a large amount of leakage magnetic flux, and in a limited space, the degree of freedom of the pump shape becomes low, so the pump performance and pump efficiency cannot be increased to a certain extent. . In other words, a pump shape that pursues performance and efficiency cannot be manufactured.

<Insulating sintered stator core>
Recently, in order to improve the degree of freedom of the shape of the stator core, an insulating sintered body formed by sintering iron powder coated with an insulator such as oxide film or resin is used instead of laminated steel sheets. It has been put to practical use. However, since the insulating sintered body contains an insulating material (non-magnetic material), there is a problem that the magnetic permeability is inevitably lower than that of a complete magnetic material. In detail, an insulating sintered body can be shaped to accommodate the flow of magnetic flux aimed at improving the efficiency of the electromagnet itself, but it contains a non-magnetic material such as phosphate or synthetic resin, so the magnetic permeability of the material itself Is low, the magnetic field strength cannot be increased too much. Laminated steel sheets and insulating sintered bodies have been used for stator cores for some time, but each has drawbacks.

The third problem is that there are many magnetic leaks.
If the stator core has a shape corresponding to the flow of magnetic flux, there is no waste of magnetic force, and the efficiency of the stator (electromagnet) portion can be improved. However, in laminated steel sheets, there is a limit to the shape with a high degree of freedom due to the superposition of the steel sheets, and magnetic leakage (unused magnetic force) will inevitably increase. Therefore, there has been a limit in improving the efficiency of the electromagnet portion in the laminated steel sheet. Insulating sintered bodies with a high degree of freedom in shape can be shaped to correspond to the flow of magnetic flux, so it is possible to reduce magnetic leakage, but the magnitude of the magnetic force generated due to the low magnetic permeability as described above. Has the problem of becoming low.

  Regarding the degree of freedom of shape described above and the large amount of magnetic leakage, each of the laminated steel sheets and the insulating sintered body has drawbacks. For this reason, the problem (technical problem or object) to be solved by the present invention is to solve at least one of the first, second and third problems.

  Accordingly, as a result of intensive researches to solve the above problems, the inventor has found that the invention of claim 1 is applied to a water pump or the like in which an inner rotor magnet below an impeller is rotatably provided inside a stator core as an electromagnet. In the DC motor, the stator core is connected to the lower stator core having a stator pole around which coil wires arranged at even intervals of 4 or more and equidistant from the inner peripheral side of the cylindrical lower stator core main body are wound. The upper rotor core is formed on the inner peripheral side of the upper end of the cylindrical upper stator core corresponding to the number of stator poles, and has an upper stator core having a top protrusion that is not connected to the lower stator core. However, the number of magnetic poles corresponds to the number of magnetic poles of the stator core, and the upper and lower The stator core is composed of an insulating sintered core, and the inner rotor magnet is composed of a plastic magnet or an embedded magnet. The magnetic poles of the top protrusion and the magnetic pole of the upper rotor magnet body The above problem was solved by using a pump DC motor that was controlled so as to be sucked and repelled.

  According to a second aspect of the present invention, the above-mentioned problem is solved by using a DC motor for pumps in which the lower stator core of the stator core is composed of laminated steel sheets in the above-described configuration. Furthermore, the invention of claim 3 is characterized in that, in the above-described configuration, the stator core is provided on the inner periphery, and the inner rotor magnet is provided on the outer periphery of the stator core as an outer rotor magnet. As a result, the above-described problems have been solved.

  In the first aspect of the invention, the impeller can be driven by the attractive force of the magnets on the two surfaces in the radial direction (impeller and lower stator core) and the thrust direction (impeller and upper stator core), so the impeller is driven more efficiently. The efficiency can be improved over a conventional one-way suction electric water pump as seen in the prior art. In addition, since the attractive force is acting in the thrust direction (impeller and upper stator core), the attractive force in the opposite direction to the impeller thrust can be generated, making it possible to largely cancel out the impeller thrust and significantly improve the impeller bearing life. And can be improved. As described above, the magnetic force in the thrust direction of the insulating sintered body has two roles of rotating the impeller and canceling the thrust of the impeller. Furthermore, although the magnetic attraction force is generated on two surfaces, it is not necessary to use two magnets, and it is possible to use one space, contributing to space saving and weight reduction.

  Furthermore, in the invention of claim 1, taking advantage of the large degree of freedom of shape of the insulating sintered body, an ideal stator shape is aimed at improving efficiency in accordance with the pump shape, which was impossible with laminated steel sheets. Is possible. That is, the efficiency of the stator is improved, that is, the pump size can be improved because the limited space can be effectively used for the pump shape. Also, since the insulating sintered body is attached or assembled to the laminated steel sheet after the coil wire is wound around the laminated steel sheet, the coil wire can be wound in a short time, leading to a reduction in manufacturing time (cycle time). it can.

  Further, in the invention of claim 2, a stator core having a low magnetic leakage and a high magnetic permeability can be obtained by adopting a two-layered structure of an insulating sintered body and a laminated steel plate. In the invention of claim 3, although there is a difference that the rotating impeller is on the inner peripheral side and the outer peripheral side, the same effect as that of the invention of claim 1 or 2 is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 5 show the first embodiment. In particular, in 1st Embodiment, the stator core (electromagnet) 1 whole is comprised by the insulating sintered compact core divided into two. The stator core 1 is provided on the outer periphery of the DC motor, and the inner rotor magnet (inner peripheral rotating portion) 2 is rotatably provided on the inner periphery. An impeller 3 is integrally formed on the inner rotor magnet 2. As a specific structure, a partition wall 4 is provided between the stator core 1 and the inner rotor magnet 2, and cooling water is sealed by the partition wall 4.

The stator core 1 includes a lower stator core 11 and an upper stator core 12, both of which are formed of an insulating sintered core and are formed as separate bodies.
The lower stator core 11, the lower stator core body 11a on the outer peripheral side of the upper stator core 12, and the upper stator core body 12a are all formed in a cylindrical shape with the same diameter and the same thickness. Stator poles 11b, 11b,..., Which are arranged at intervals of 60 degrees from the inner peripheral side of the lower stator core main body 11a of the lower stator core 11 and are composed of bar pieces such as bifilar winding the coil wire m and enormous inner end portions, are provided. And configured as 6 poles. Further, top protrusions 12b, 12b,... Arranged at intervals of 60 degrees are provided on the inner peripheral side of the upper stator core body 12a of the upper stator core 12.

  A coil wire m is wound around the stator poles 11b, 11b,... Of the lower stator core body 11a. Thereafter, the upper stator core 12 made of an insulating sintered body core is bonded to the upper end of the lower stator core 11 with an adhesive or the like. With such a configuration, the circuit is configured such that any poles have different polarities when energized. Since this circuit configuration is known, it will not be described in detail. At this time, the top protrusions 12b, 12b,... Have the same magnetic pole as that excited by the lower stator core body 11a.

Specifically, as shown on the right side of FIG. 1 (A), when the inner end of the stator pole 11b is an S pole, the lower stator core body 11a is an N pole, so that the upper stator core body 12a and The top protrusion 12b is excited with the same magnetic pole N as the N magnetic pole excited in the lower stator core body 11a.
The upper stator core 12 that is an insulating sintered body needs to be connected to the outer peripheral side of the lower stator core 11 that is an insulating sintered body. If the inner peripheral side is also connected, the magnetic field from the upper stator core 12 to the lower surface of the impeller 3 of the inner rotor magnet 2 is not generated. That is, when the inner peripheral side is also connected, the insulating sintered bodies are connected over the entire circumference, so that the magnetic pole cannot be divided into the N pole and the S pole, and a magnetic field is not generated.

  As described above, the electromagnet portion called the stator core 1 is composed of two parts, the lower stator core 11 and the upper stator core 12, and the lower stator core 11 that is an insulating sintered core around which the coil wire m is wound, The upper stator core 12 is provided with an upper sintered core 12b having a top projection 12b, which is an L-shaped cross section extending in the direction of the impeller 3 connected thereto. By adopting such a structure, a normal electromagnet which can generate magnetic flux in only one direction can generate magnetic flux in two directions by the lower stator core 11 portion and the upper stator core 12 portion.

  The inner rotor magnet 2 includes a cylindrical lower rotor magnet main body 21 and an upper rotor magnet main body 22 that covers the entire lower surface of the impeller 3 and protrudes in a cylindrical shape on the lower center side, both of which are plastic magnets. Or it is comprised with the embedded magnet and formed as one. First, the lower rotor magnet main body 21 is configured as a permanent magnet so that the circumference is divided into six equal intervals at intervals of 60 degrees, and alternates with S poles, N poles,. The lower rotor magnet main body 21 is provided with a cylindrical gap 21a on the lower surface as necessary, and the upper surface is formed flat. The upper rotor magnet main body 22 is integrally formed with a bowl-shaped portion 22a that covers the entire lower surface of the impeller 3 and a short cylindrical piece 22b below it.

  The upper rotor magnet main body 22 is also configured as a permanent magnet so that the circumference is divided into six equal intervals at intervals of 60 degrees, and alternates with S poles, N poles,. The upper rotor magnet body 22 is integrally formed at the upper end of the lower rotor magnet body 21 thus configured. At this time, the magnetic poles of the lower rotor magnet main body 21 and the magnetic poles of the upper rotor magnet main body 22 are configured to be different. Specifically, as shown in FIG. 1 (A), when the right side of the lower rotor magnet body 21 is an N pole, the right side of the upper rotor magnet body 22 is an S pole. ing. Thus, the impeller 3 with the inner rotor magnet 2 having a built-in permanent magnet is rotated by the magnetic attractive repulsive force of the stator core 1.

  As described above, in the present invention, since the magnetic fields of the two surfaces of the stator core 1 are reversed, the N of the two magnets in the radial (circumferential) direction and the thrust (axial) direction on the side of the impeller 3 corresponding thereto. Since the impeller 3 cannot rotate due to the magnetic attraction and repulsion force unless the N pole and the S pole are reversed in the thrust direction and the radial direction in the thrust direction and the radial direction, the impeller 3 has the thrust direction and the radial direction (long cylinder). The magnetic poles in which the N pole and the S pole are reversed are formed on the side and the blade support disk side).

  In the first embodiment, the entire stator core (electromagnet) 1 is formed of an insulating sintered body, and both the lower stator core 11 (electromagnet mounting portion) and the upper stator core 12 (impeller side) are both insulating sintered bodies. By using, it is possible to make a shape that pursues a highly flexible efficiency corresponding to the flow of magnetic flux.

  The impeller provided with the upper rotor magnet main body 22 by the magnetic attraction and repulsive force of the top protrusion 12b of the upper stator core 12 of the stator core 1 and the magnetic poles of the flange-shaped portion 22a covering the entire lower surface of the impeller 3 of the upper rotor magnet main body 22. 3 is lowered. That is, by applying a force in the direction opposite to the thrust of the impeller 3 to the impeller 3, the wear speed of the impeller bearing can be reduced. Thereby, the life of the bearing of the impeller 3 can be extended.

  Next, the manufacturing process and operation will be described. First, the coil wire m is wound around the stator pole 11 b of the lower stator core 11. Since the upper stator core 12 which is an insulating sintered body is not yet attached at the time of winding, there is an advantage that the upper side is opened and the coil wire m can be easily wound. Further, after winding the coil wire m, the upper stator core 12 is attached or assembled. By doing so, the manufacturing time (cycle time) can be shortened. In the present invention, for example, the N pole (impeller long cylinder), the S pole (lower stator core), the S pole (impeller blade support disk), and the N pole (upper stator core) are attracted to each other on the two surfaces of the radial side and the thrust side. The impeller 3 rotates by changing the magnetic field of 1 in order.

  Next, a second embodiment of the present invention will be described. As shown in FIG. 6, a laminated steel plate p is used for the lower stator core 11 where the coil wire m is wound in the stator core 1, and the other configurations are the same, and the description thereof is omitted. That is, in the second embodiment of the present invention, the upper stator core 12 that is an insulating sintered body is provided on the upper side (impeller side) of the laminated steel sheet p that is required to have a high degree of freedom corresponding to the flow of magnetic flux. The second embodiment is a two-stage structure composed of a porous sintered body and a laminated steel sheet p. In this case, by adopting a structure in which the upper stator core 12 which is an insulating sintered body is present on the upper side (impeller side), a shape with a high degree of freedom in terms of magnetic efficiency can be obtained.

  Further, by providing the laminated steel plate p at the portion where the coil wire m of the lower stator core 11 is wound, it is possible to remarkably improve the magnetic permeability that is difficult to increase only with the insulating sintered body. Furthermore, as in the second embodiment, the laminated steel sheet p (lower stator core 11) and the magnetic leakage that have a high magnetic permeability but a large magnetic leakage are obtained by adopting a two-stage stacked structure of the insulating sintered body and the laminated steel sheet p. However, it is possible to make the stator core 1 with a small magnetic leakage and a high magnetic permeability by compensating for the disadvantages of the insulating sintered body (upper stator core 12) having a low magnetic permeability.

  Next, a third embodiment of the present invention will be described. In the first and second embodiments, an impeller 3 having a stator core (electromagnet) 1 on the outer peripheral side and an inner rotor magnet (permanent magnet) 2 on the inner peripheral side is provided. However, the third embodiment of the present invention is As shown in FIG. 7, an impeller 3 having an outer rotor magnet (permanent magnet) 5 disposed on the outer peripheral side is provided, and a stator core (electromagnet) 1 is disposed on the inner peripheral side. In this case, the stator core (electromagnet) 1 is provided in an insert state in a synthetic resin. In addition, the outer rotor magnet 5 is also configured such that the cylindrical portion and the blade support disk have different magnetic poles, and the effect of the present invention can be enjoyed even with such a configuration.

  In the configuration of the first to third embodiments described above, as the impeller 3 side permanent magnet, a sintered magnet piece may be cast in a synthetic resin, or a synthetic resin and magnetic powder are mixed and molded. Plastic magnets may be used. The number of magnetic poles of the stator core 1 and the inner rotor magnet 2 or the outer rotor magnet 5 of the impeller 3 is 6 poles in this embodiment, but may be 4 poles or 8 poles. Further, the number of poles of the stator core and the rotor magnet is not limited to the same number. In particular, the number of magnetic poles is a matter of design, but the N and S poles always exist in pairs, so they are always even poles.

  The pump DC motor of the present invention can be used for a water pump integrated with the pump DC motor, and of course, an industrial product in which life is extended by reducing thrust and other thrust is generated. The possibility of use is extremely high.

(A) is sectional drawing of 1st Embodiment of this invention, (B) is a top view as a partial cross section of the XX arrow of (A). (A) is a perspective view of the stator core of the present invention, (B) is a partially enlarged perspective view of (A), and (C) is a sectional view of (B). (A) is a top view of the upper stator core of this invention, (B) is a top view of a lower stator core. (A) is a perspective view of the upper stator core of this invention, (B) is a perspective view of a lower stator core. It is the perspective view which made the center of the inner rotor magnet of this invention the cross section. It is sectional drawing of 2nd Embodiment of this invention. (A) is sectional drawing of 3rd Embodiment of this invention, (B) is the top view made into the partial cross section of the YY arrow of (A) except the synthetic resin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stator core, 3 ... Impeller, 11 ... Lower stator core, m ... Coil wire,
11a ... lower stator core body, 11b ... stator pole, 12 ... upper stator core,
12a ... Upper stator core body, 12b ... Top projection, 2 ... Inner rotor magnet,
5 ... Outer rotor magnet.

Claims (3)

In a DC motor such as a water pump in which an inner rotor magnet below an impeller is rotatably provided inside a stator core as an electromagnet, the stator core is evenly spaced by an even number of 4 or more from the inner peripheral side of the cylindrical lower stator core body. a lower stator core having a stator poles that wound around the arranged coil wire with a, formed corresponding to said stator poles number on the inner peripheral side than the upper end of the cylindrical upper stator core body for connecting with said lower stator core, the lower An upper stator core having a top protrusion that is not connected to the stator core , wherein the inner rotor magnet is divided into upper and lower parts , the number of magnetic poles corresponds to the number of magnetic poles of the stator core , and the upper and lower magnetic poles are different. The stator core is an insulating sintered core, and The inner rotor magnet is composed of a plastic magnet or the embedded magnets, pump DC motor in which the magnetic poles of the magnetic pole and the upper rotor magnet body of said top projection is characterized by comprising controlled to suction-repulsion.   2. The pump DC motor according to claim 1, wherein the lower stator core of the stator core is made of a laminated steel plate.   3. The pump DC motor according to claim 1, wherein the stator core is provided on the inner periphery and the inner rotor magnet is provided on the outer periphery of the stator core as an outer rotor magnet.

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