JP2010063285A - Motor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor equipped with a rotor with a magnet arranged in a slot of a rotor core, and a rotational angle detection means which detects the rotational angle of the rotor on the basis of a magnetic field generated from the magnet, which is configured to improve a holding force of a magnet while suppressing burrs of a sealing resin at the end of the side of a rotational angle detection means. <P>SOLUTION: In the rotor 3, an area including at least the magnet 25 is sealed with the sealing resin 27 when viewing the end of the side of the rotational angle detection means from the axial direction of the rotor 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a rotor in which a magnet is held in a slot of a rotor core and at least a part of which is sealed with a sealing resin, and a rotation angle for detecting the angular position of the rotor based on the magnetic field of the magnet In particular, the present invention relates to a technical field of a sealing structure using a sealing resin for the rotor.

  Conventionally, motors have been used as drive sources for various devices. A motor having a general configuration includes a substantially cylindrical stator having a plurality of phase windings, and a rotor having a plurality of magnets and arranged rotatably inside the stator. ing. As a configuration of this rotor, for example, as disclosed in Patent Document 1, there is a so-called magnet-embedded type (IPM motor) in which magnets are arranged in slots of a rotor core formed by laminating a plurality of steel plates. Are known.

  In such an IPM motor, the magnet is fixed to the rotor core by sealing the magnet together with the rotor core with a sealing resin in a state where the magnet is disposed in the slot of the rotor core. I have to.

  A motor having the above-described configuration is generally configured such that a rotor including the magnet is provided by sequentially energizing a plurality of phase windings of the stator in order to generate a rotating magnetic field in the stator. It is driven to rotate. That is, the motor is configured to control the rotational speed of the rotor by controlling the timing of energizing the windings of the stator, and for this control, the angular position of the rotor is controlled. And the detection result is fed back to the energization control of the winding.

  As a method of detecting the angular position of the rotor, conventionally, a magnetic field generated by a magnet in the rotor is detected by a plurality of sensors, and the angular position of the rotor is determined based on the detection results of these sensors. Methods for identifying are known.

For example, in the case of the configuration disclosed in Patent Document 1, the outer periphery of the rotor is exposed such that the outer periphery of the rotor of the magnet is exposed at the sensor-side end of the axial end of the rotor. The other parts excluding the side parts are sealed with a sealing resin. Although not specifically disclosed in Patent Document 1, the angular position of the rotor is specified by detecting a magnetic field generated from the exposed magnet with a sensor.
JP 2006-158092 A

  By the way, the configuration in which the rotor outer peripheral side of the magnet is exposed as described above allows the sensor to be disposed closer to the magnet, so that the magnetic field generated by the magnet can be accurately detected by the sensor. When a portion other than the outer peripheral side of the rotor is sealed with a sealing resin at the end on the sensor side, the portion covered with the sealing resin across the rotor core and the magnet is exposed at the end of the rotor. Part to be formed.

  Here, the rotor is formed by injecting molten sealing resin into a mold in which a rotor core containing a magnet is disposed, and solidifying the sealing resin. Therefore, as described above, when a boundary portion between the portion covered with the sealing resin and the exposed portion is formed at a position straddling the rotor core and the magnet, the magnet protrudes from the rotor core in the axial direction. In addition, there is a possibility that a gap is generated between the rotor core and the mold, and the sealing resin protrudes from the gap to the exposed portion, resulting in a defective burr. When such sealing resin burrs are generated, not only the appearance of the burrs is deteriorated, but also problems such as noise when the rotor rotates or burrs may be peeled off may occur. .

  In addition, in the configuration of the above conventional example, the magnet disposed in the slot of the rotor is not entirely covered with the sealing resin and is partially exposed. The holding power of the magnet in the core is reduced.

  The present invention has been made in view of these points, and an object of the present invention is to provide a rotor in which a magnet is disposed in a slot of a rotor core, and the rotor based on a magnetic field generated from the magnet. In the motor provided with the rotation angle detection means for detecting the rotation angle of the magnet, it is possible to improve the holding force of the magnet while suppressing the generation of sealing resin burrs at the end on the rotation angle detection means side as much as possible. It is to obtain a simple configuration.

  In order to achieve the above object, in the motor according to the present invention, the rotor in which the magnet is disposed in the slot of the rotor core is sealed so as to cover at least the magnet when viewed from the end in the axial direction. By sealing with resin, generation | occurrence | production of the burr | flash of sealing resin was suppressed as much as possible, and it was made possible to hold | maintain the said magnet more reliably in a rotor core.

  Specifically, the first invention is a rotor in which at least a part is sealed with a sealing resin so that magnets are respectively held in a plurality of slots formed in a substantially cylindrical rotor core. And a rotation angle detection unit that is disposed outside the rotor in the axial direction and detects an angular position of the rotor based on a magnetic field generated from the magnet.

  The rotor is sealed with the sealing resin in a range including at least the magnet when the end on the rotation angle detecting means side is viewed from the axial direction of the rotor.

  With the above configuration, the range including the magnets arranged in the slots of the rotor core as viewed from the axial direction of the rotor is sealed with the sealing resin at the end of the rotor on the rotation angle detection means side. Thus, the magnet can be more reliably held in the slot of the rotor core. In addition, as described above, the range including at least the magnet as viewed from the axial direction of the rotor is sealed with a sealing resin, so that a part of the magnet is sealed with a sealing resin so as to be exposed. Unlike the configuration, the boundary portion between the portion covered with the sealing resin and the portion not covered is formed on the outer surface of only the rotor core, which is caused by the step between the rotor core and the magnet. The burr of the sealing resin generated in the rotor can be reduced.

  Here, as described above, in the case of the configuration in which the angular position of the rotor is detected by the rotation angle detection means based on the magnetic field generated from the magnet in the rotor, the rotation angle of the magnet as in the first invention. If the detection means side is covered with sealing resin, depending on the thickness of the sealing resin, the distance between the rotation angle detection means and the magnet is increased, and the magnetic field generated from the magnet can be accurately detected by the rotation angle detection means. It may disappear. If it does so, the detection accuracy of the angular position of the said rotor may fall.

  Therefore, the rotor is formed with a resin layer made of the sealing resin on the outer surface of both end portions in the axial direction, and the rotor is a resin in a portion where a magnetic field is detected by the rotation angle detecting means. It is assumed that the thickness of the layer is thinner than the thickness of the resin layer at the end portion in the axial direction opposite to the rotation angle detecting means side of the rotor (second invention).

  As a result, the thickness of the resin layer at the portion where the magnetic field is detected by the rotation angle detection means in the rotor is thinner than the thickness of the resin layer at the opposite axial end, so that the magnet is sealed with the sealing resin. Without losing the holding force held in the rotor core, the rotation angle detection means can be arranged at a position closer to the magnet in the rotor slot, and the rotation angle detection means allows the magnet to be disposed. It is possible to more reliably detect the magnetic field. Therefore, the detection accuracy of the angular position of the rotor can be improved with the above-described configuration.

  In addition, as described above, by forming a resin layer on the outer surface of both axial end portions of the rotor, the resin layer can absorb variations in the axial dimension of the rotor core. Generation | occurrence | production of the burr | flash of sealing resin in a direction both ends can be suppressed.

  In the second aspect of the invention, the rotor has the molten sealing resin opposite to the rotation angle detecting means side in the mold in a state where the rotor core and the magnet are arranged in the mold. It is preferable to be sealed with the sealing resin by being injected from the end portion on the side and solidified (third invention).

  Thus, the sealing resin is injected by injecting the molten sealing resin from the end opposite to the rotation angle detecting means side in the axial direction both ends of the rotor. The resin can easily flow into the mold, and the workability during the resin molding can be improved.

  In the rotor, the thickness of the resin layer in the portion where the magnetic field is detected by the rotation angle detection means is thinner than the thickness of the resin layer in the other portion at the end on the rotation angle detection means side. Is preferable (fourth invention).

  By doing so, the rotation angle detection means can be brought closer to the magnet in the rotor slot at the end of the rotor on the rotation angle detection means side, and the rotor angular position by the rotation angle detection means can be approached. When the molten sealing resin is poured by increasing the thickness of the resin layer other than the portion for detecting the magnetic field, the flow of the sealing resin at the end on the rotation angle detecting means side can be improved. Can be improved.

  That is, in order to bring the rotation angle detection unit closer to the magnet, it is necessary to reduce the thickness of the resin layer on the rotation angle detection unit side of the rotor. In this case, the rotation angle detection of the rotor is performed in the mold. The gap in which the molten sealing resin flows on the means side becomes narrow, and the sealing resin is difficult to flow. On the other hand, by adopting the configuration as described above, it is possible to achieve both improvement in detection accuracy of the angular position of the rotor and improvement in workability during resin molding.

  In the rotor, the rotor core and the magnet are arranged in a mold, and the magnets in the plurality of slots are at the same axial position at the end of the rotor on the rotation angle detection means side. The molten sealing resin is injected from the end of the mold opposite to the rotation angle detecting means side and solidified while being held by the holder so as to be lined up. (5th invention).

  That is, the rotor is formed with an exposed portion at the end on the rotation angle detecting means side so that a portion held by the holder is exposed without being covered with the sealing resin, and the rotation angle It is assumed that a gate mark portion as an entrance portion when the sealing resin is injected is formed in the resin layer provided at the end opposite to the detection means side (sixth invention).

  Thus, at the end of the rotor on the rotation angle detection means side, the magnets in the slots are held by the holder so as to be aligned at the same axial position, and on the opposite side of the end on the rotation angle detection means side. By causing the molten sealing resin to enter from the end, the magnet is moved to the rotation angle detecting means side by the injection pressure of the sealing resin (corresponding to the flow pressure when the molten sealing resin flows into the mold). It can be pushed and brought into contact with the holder. Therefore, since the plurality of magnets can be accurately arranged at the same position in the axial direction of the rotor, the magnetic field of each magnet can be accurately detected by the rotation angle detecting means, and the angular position of the rotor can be detected. The detection accuracy can be improved.

  In the fifth or sixth aspect of the invention, when the sealing resin is injected into the resin layer provided at the end of the rotor opposite to the rotation angle detection means side. It is preferable that a recess is formed by the tip of the second holder disposed so as to be separated from the end by a predetermined distance in the axial direction (seventh invention).

  Accordingly, when the sealing resin is injected from the opposite end while holding the magnet by the holder at the end of the rotation angle detecting means side of the rotor, the rotor is injected by the injection of the sealing resin. The second holder can surely prevent the magnet in the core from floating toward the rotation angle detecting means by a predetermined amount or more.

  In addition, since the second holder is disposed at a predetermined distance from the end of the rotor on the rotation angle detecting means side in the axial direction, an excessive force acts on the magnet from the second holder. The magnet can be prevented from being damaged. That is, if the magnet is sandwiched between the holder and the second holder, an excessive force may be applied to the fragile magnet and the magnet may be damaged. By separating from the magnet, it is possible to reliably prevent an excessive force from acting on the magnet.

  Furthermore, as described above, by separating the second holder from the magnet, the rotor can be easily placed in the mold even if the magnet has dimensional variations. The workability at the time can be improved.

  In the above configuration, the rotor core is formed by laminating a plurality of steel plates (eighth invention). Thus, in the case where the rotor core is formed by laminating a plurality of steel plates, due to variations in the size of the steel plates, etc., variations in the size of the steel plates in the lamination direction occur, and the axial direction of the rotor core Since a gap is easily generated between the end portion and the mold, the sealing resin protruding from the gap becomes a burr. That is, in the case of the above-described configuration, it is easy to generate sealing resin burrs, but by applying the above-described configuration of the first invention, generation of sealing resin burrs can be suppressed as much as possible. it can.

  The rotation angle detection means is preferably arranged so as to overlap the magnet on the outer peripheral side of the rotor when viewed from the axial direction of the rotor (9th invention). Generally, on the inner peripheral side of the rotor, it is easily affected by the magnetic field of the entire rotor. For this reason, it is preferable to provide the rotation angle detecting means on the outer peripheral side of the rotor, but there is no magnet at the outer peripheral end, and only the rotor core or the magnetic field on the stator side is easily affected. . On the other hand, as described above, the rotation angle detection means is arranged at a position that overlaps with the magnet when viewed from the axial direction of the rotor on the outer peripheral side of the rotor, thereby receiving the influence of disturbance as much as possible. The magnetic field generated from the magnet can be reliably detected.

  In the motor manufacturing method according to the tenth aspect of the invention, the magnet is covered with the sealing resin on the rotation angle detecting means side of the rotor in the slot of the rotor core formed by laminating a plurality of steel plates, and substantially in the axial direction. Hold the magnet so that it is aligned in the same position and inject sealing resin from the opposite side to minimize the generation of burr in the sealing resin, and secure the magnet to the rotor core. I was able to hold it.

  Specifically, a rotor at least partially sealed with a sealing resin so that the magnets are respectively held in a plurality of slots formed in the substantially cylindrical rotor core, and the rotor The present invention is directed to a method of manufacturing a motor including rotation angle detection means that is disposed outward in the axial direction and detects an angular position of the rotor based on a magnetic field generated from the magnet.

  Then, by laminating a plurality of steel plates each having a slot portion constituting the slot, a rotor core forming step for forming the rotor core, and a rotation angle of the magnet in the slot of the rotor core While holding the plurality of magnets by the holder so that the entire detection means side is covered with the sealing resin and the magnets are arranged at the same position in the axial direction of the rotor on the rotation angle detection means side. And a resin injection step of injecting the sealing resin from the side opposite to the rotation angle detecting means side with respect to the rotor core and magnet arranged in the mold.

  By the above method, the plurality of magnets arranged in the rotor slot are covered with the sealing resin as a whole on the rotation angle detection means side. Since it can be held more securely with respect to the rotor core, a boundary portion between the portion covered with the sealing resin and the portion not covered is formed on the outer surface of only the rotor core. Occurrence of burrs of the sealing resin at the child can be suppressed.

  In addition, in the rotor core slot, the plurality of magnets are held by the holding tool so that the rotation angle detection side is covered with the sealing resin and the magnets are aligned at the same position in the axial direction of the rotor. Since the sealing resin enters from the opposite side, the plurality of magnets can be arranged at the same position in the axial direction on the rotation angle detection means side, and the magnetic field of all the magnets can be reliably and accurately arranged by the rotation angle detection means. Can be detected.

  As described above, according to the motor of the present invention, the rotor sealed with the sealing resin in a state where the magnet is held in the slot of the rotor core, and the magnetic field that generates the angular position of the rotor from the magnet. The rotation angle detection means for detecting the rotation angle based on the rotation angle detection means side end of the rotor as viewed from the axial direction, at least a range including the magnet is sealed with a sealing resin. Therefore, the magnet can be held more reliably, and the generation of burr of the sealing resin can be suppressed as much as possible. Accordingly, the strength and appearance of the rotor can be improved.

  Further, according to the second invention, since the rotor has a thickness of the resin layer at a portion where the magnetic field is detected by the rotation angle detection means, which is thinner than the thickness of the resin layer at the opposite end, The detection accuracy of the angular position of the rotor by the rotation angle detection means can be improved.

  According to a third aspect of the invention, the rotor is sealed by the sealing resin injected from the opposite end in a state where the rotor is disposed in the mold, so that the mold is sealed in the mold. The stop resin can easily flow, and the workability during resin molding can be improved.

  According to the fourth invention, since the thickness of the resin layer at the end of the rotor on the side of the rotation angle detection means is thinner than the thickness of the resin layer at the other part, the rotor by the rotation angle detection means While improving the detection accuracy of the angular position, it is possible to improve the workability during resin molding.

  According to a fifth aspect of the present invention, the rotor is held by the holder so that the magnets in the slots are aligned at substantially the same axial position at the end on the rotation angle detection means side, and the end on the opposite side thereof. Since it is sealed with the sealing resin injected from the part, the angular position of the rotor can be accurately detected by the rotation angle detecting means.

  Further, according to the sixth invention, the rotor having the configuration of the fifth invention has the exposed portion formed by the holder at the end on the rotation angle detecting means side, and on the opposite end. Since the gate trace portion when the sealing resin is injected is formed, the same effect as the fifth invention can be obtained with the rotor having such a configuration.

  According to the seventh invention, in the manufacturing process of the rotor, the second holder is arranged at a predetermined distance in the axial direction with respect to the end of the rotor on the rotation angle detecting means side. Therefore, it is possible to reliably prevent the magnet from being lifted by a predetermined amount or more when injecting the sealing resin while preventing breakage of the magnet.

  According to the eighth invention, since the rotor core is formed by laminating a plurality of steel plates, burrs of the sealing resin are likely to occur. However, by using the configuration of the first invention, the rotor core is sealed. Generation | occurrence | production of the burr | flash of a stop resin can be suppressed.

  According to the ninth aspect of the invention, the rotation angle detection means is arranged so as to overlap the magnet on the rotor outer peripheral side when viewed from the axial direction of the rotor, and therefore the magnetic field of the entire rotor. The magnetic field of the magnet can be detected reliably and accurately without being influenced by the magnetic field of the stator or the magnetic field of the stator.

  According to the method for manufacturing a motor according to the tenth aspect of the present invention, the plurality of magnets held in the rotor core slot formed by laminating a plurality of steel plates are covered with the sealing resin on the rotation angle detecting means side. Thus, it is possible to obtain a motor capable of suppressing the generation of burr of the sealing resin as much as possible while increasing the holding power of the magnet. In addition, the magnet is sealed by a sealing resin that is injected into the mold from the opposite side while being held by the holder so as to be aligned at substantially the same position in the axial direction on the rotation angle detection means side of the rotor. Therefore, the detection accuracy of the angular position of the rotor by the rotation angle detection means can be improved.

  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-
FIG. 1 shows a schematic configuration of a motor 1 according to an embodiment of the present invention. The motor 1 has a substantially cylindrical rotor 3 disposed in a substantially cylindrical stator 2, and supplies power to the windings 12 of the stator 2 at a predetermined timing by a control circuit (not shown). Thus, the rotor 3 is driven to rotate with respect to the stator 2. The motor 1 is used as a motor for rotating a fan, such as a drive motor for an outdoor fan of an air conditioner.

  The stator 2 includes a stator core 11 formed by laminating a plurality of steel plates, and a plurality of windings 12, 12,... Wound around the stator core 11. Although not particularly illustrated, each steel plate constituting the stator core 11 has a ring-shaped core back portion and a plurality of teeth portions projecting inward from the core back portion, and these are laminated. By doing so, the core back part and teeth part of the stator core 11 are comprised. The plurality of windings 12, 12,... Are wound around the teeth portion. That is, these windings 12, 12,... Are arranged in a substantially annular shape around the axis P so as to form a substantially cylindrical space in which the rotor 23 can be accommodated.

  As shown in FIG. 1, the portion around which the winding 12 is wound on the stator core 11 is insulated to electrically insulate between the stator core 11 and the winding 12. A portion 13 is provided.

  The stator 2 is entirely sealed with a sealing resin. That is, the stator 2 is embedded in a substantially bottomed cylindrical casing 4 of the motor 1 made of the sealing resin. The casing 4 is covered at its opening side by a substantially disc-shaped cover member 5, thereby forming a substantially columnar space for accommodating the rotor 3 in the casing 4. .

  On the inner peripheral surface of the casing 4, a substrate 40 on which a rotation position detection circuit including a sensor 41 (rotation angle detection means) for detecting the angle position of the rotor 3 is formed is a resin substrate holder. 42 is provided. The substrate holder 42 is screwed to a predetermined position of the casing 4 so that the sensor 41 on the substrate 40 is positioned at a position where the angular position of the rotor 3 can be detected with high accuracy, as will be described later. It is configured.

  Here, the configuration of the rotational position detection circuit will be briefly described. The rotational position detection circuit has three sensors 41 (for example, a magnetic sensor composed of a Hall element) arranged at an electrical angle of 120 degrees. Thus, the angular position of the rotor 3 is detected by synthesizing signals output from the sensor 41 in accordance with the angular position of the rotor 3. The angular position of the rotor 3 detected by the rotational position detection circuit is transmitted as a rotational position signal to a control means (not shown), and the control means controls the timing of energizing the winding 13 of the stator 2. Used.

  In the present embodiment, the sensor 41 is a magnetic sensor that can detect the magnetic field generated from the magnet 25 in the rotor 3, so that the magnetic field of the magnet 25 can be reliably and accurately detected. It is necessary to arrange the sensor 41. Specifically, since the magnets 25 are arranged radially in the rotor 3 as will be described later, when the sensors 41 are arranged on the inner peripheral side of the rotor 3, each magnet in the rotor 3 is arranged. Since the magnets 25 are close to each other and become close to a portion where the magnetic fluxes generated from the magnets 25 are concentrated, the magnetic field of each magnet 25 cannot be detected accurately. Further, even when the sensor 41 is arranged on the outer peripheral end side of the rotor 3, the sensor 41 is affected by the magnetic flux generated from the winding 13 of the stator 2, or the magnet 25 is not present. The magnetic field of the magnet 25 cannot be detected with high accuracy. Further, when the mounting position of the sensor 41 is shifted, if the amount of shift is the same, the ratio of error to the circumferential length is smaller on the outer circumferential side than on the inner circumferential side. It is preferable to arrange in the above.

  Therefore, in consideration of these points, the position is not the inner peripheral side of the rotor 3 and is not the outer peripheral end, that is, the position on the outer peripheral side of the rotor 3 and overlapping the magnet 25 in plan view. In addition, the sensor 41 may be disposed. The outer peripheral side of the rotor 3 is preferably, for example, a position on the outer side of the magnet 25 in the radial direction center position of the rotor 3. Note that the position of the sensor 41 may actually be obtained through experiments or the like so that the magnetic field of the magnet 25 can be accurately detected.

  The substrate 40 is attached to the substrate holder 42 with screws 43 as shown in FIG. Specifically, a protrusion 42a having a protrusion height substantially the same as the thickness of the substrate 40 is integrally provided on the surface of the substrate holder 42 on the substrate mounting side, and the protrusion 42a includes the substrate 42a. A screw hole portion 42b having a screw groove is provided on the inner peripheral surface so as to penetrate the holder 42 in the thickness direction. On the other hand, the substrate 40 is formed with an insertion hole 40a through which the protrusion 42a of the substrate holder 42 can be inserted. With this configuration, the screw 43 is screwed into the screw hole portion 42b of the protrusion 42a in a state where the protrusion 42a of the substrate holder 42 is inserted into the insertion hole 40a of the substrate 40, whereby the screw The substrate 40 can be sandwiched between the head of 43 and the substrate holder 42. Therefore, even when the screw 43 is turned too much, the head of the screw 43 comes into contact with the protrusion 42a of the substrate holder 42, and the substrate 40 is deformed or damaged by the pressing force from the head. You can prevent it.

  As shown in FIG. 1, the rotor 3 is configured to rotate integrally with a rotating shaft 21 that passes through the central portion thereof. The rotary shaft 21 is rotatably supported by bearings 6 and 7 at both ends, and one end protrudes outside the casing 4 so that the rotation of the rotor 3 can be output to the outside. ing. Specifically, the bearing 6 is disposed at the bottom of the substantially bottomed cylindrical casing 4, and the rotating shaft 21 passes through the bottom of the casing 4. On the other hand, the bearing 7 is disposed on the cover member 5 that covers the opening side of the casing 4, and the other end of the rotating shaft 21 is positioned inward of the casing 4 with respect to the cover member 5. ing. The bearings 6 and 7 are attached to the resin casing 4 and the aluminum alloy cover member 5 via metal brackets 8 and 9, respectively.

  As shown in FIG. 4, the rotor 3 is housed in a rotor core 23 formed by laminating a plurality of steel plates and a plurality of slots 24, 24,... Formed in the rotor core 23, respectively. And a substantially rectangular parallelepiped magnet 25. Each steel plate constituting the rotor core 23 has a ring-shaped central portion and a pole piece portion having a substantially isosceles triangular shape in plan view integrally formed so as to extend radially outward from the central portion in the radial direction. The central portion 23a and the pole piece portion 23b of the rotor core 23 are configured by stacking them. With this configuration, in the rotor core 23, slots 24 for accommodating the magnets 25 are formed radially between the pole piece portions 23b with the central portion 23a as a center. Therefore, the magnets 25 arranged in the slots 24 are also arranged radially around the axis P. In each steel plate constituting the rotor core 23, the slit portion formed between the pole piece portions corresponds to the slot portion of the present invention.

  The slot 24 is formed in a rectangular shape in a plan view, and is formed so that the width dimension of the outer peripheral end portion becomes small. That is, each pole piece portion 23b forming the slot 24 is provided with a protruding portion 23c protruding in the circumferential direction at the outer peripheral end portion thereof. The protrusion 23c restricts the movement of the magnet 25 inserted in the slot 24 from the axial direction outward in the radial direction before being sealed by the sealing resin 27. Movement in the direction is allowed. The magnet 25 has a north pole or a south pole magnetized on the side facing the side surface of the pole piece portion 23b, and sandwiches the pole piece portion 23b in the plurality of slots 24, 24,. It is arranged so that the same poles face each other.

  Each pole piece portion 23b is provided with caulking portions 23e and 23e for joining the steel plates by welding or caulking when laminating a plurality of steel plates. The pole piece portion 23b is also provided with a through hole 26 penetrating in the thickness direction (steel plate laminating direction). As will be described later, the through hole 26 is used to facilitate the flow of the molten sealing resin 27 in the thickness direction of the rotor 3 when the rotor 3 is sealed with the sealing resin 27. .

  The central portion 23a is formed to have an inner diameter smaller than the outer diameter of the shaft portion 21 so that the shaft portion 21 can be fitted inside. Further, on the outer peripheral surface of the central portion 23a and between the pole piece portions 23b, there is a substantially triangular ridge portion 23d in a plan view that protrudes radially outward across the axis P direction. Is provided. By providing such a protrusion 23d, the magnet 5 accommodated in the slot 24 can be supported from the radially inner side.

  The rotor 3 having the above-described configuration is sealed with a sealing resin 27 made of, for example, a thermoplastic resin. Specifically, as shown in FIGS. 1, 2, and 3, the rotor 3 is configured to cover the entire magnet 25 in a state where the magnet 25 is accommodated in each slot 24 of the rotor core 23. The sealing resin 27 is provided on both surfaces of the end portion in the axial direction. As a result, the resin layer 28 is formed at the detection end of the sensor 41 and the resin layer 29 is formed at the opposite end of the axial end of the rotor core 23. Here, the sealing resin 27 covers the whole of the magnet 25 when the magnet 25 is accommodated in the slot 24 and includes at least the gap formed in the slot 24. This means that the outer surface of the magnet 25 is hidden at the axial end.

  Thus, by covering the entire magnet 25 with the sealing resin 27, the magnet 25 and the rotor core 23 can be reliably integrated, and a part of the magnet 25 (the axis of the magnet 25) The holding force of the magnet 25 can be increased as compared with the conventional configuration in which a part of both sides of the direction end portion is exposed.

  In addition, in the resin layer 28, the boundary portion between the portion covered with the sealing resin 27 and the portion 28b (hereinafter, non-covered portion) that is not covered straddles the rotor core 23 and the magnet 25 as in the conventional configuration. The formation of burrs due to the sealing resin 27 can be suppressed by forming the portion only on the rotor core 23 (the outer peripheral side and the inner peripheral side where the magnet 25 does not exist). it can. That is, in the conventional configuration in which the boundary portion is formed so as to straddle the rotor core 23 and the magnet 25, the molding die arranged on the sensor detection side at the time of sealing resin injection molding as described later is the rotor. Since the magnet 25 protrudes from the rotor core 23 in order to come into contact with a portion straddling the core 23 and the magnet 25, a minute gap is formed when the mold is brought into contact, and the gap is sealed by the gap. The burr | flash of the resin 27 will generate | occur | produce. On the other hand, when the boundary portion is formed only on the rotor core 23 as described above, the mold comes into contact with only the rotor core 23, and the rotor core 23 and the mold Therefore, it is difficult to form a gap that causes burrs between the two.

  On the other hand, the rotor core 23 is formed by laminating a plurality of steel plates, and the thickness dimension of the steel plates and the gap dimension between the steel plates are accumulated according to the number of laminated steel plates. For this reason, burrs may occur due to an error in the dimension in the axial direction. On the other hand, in the present embodiment, as described above, the resin layer 29 is provided so as to cover the entire axial end portion of the rotor core 23 (excluding a part of the inner peripheral side portion). The resin layer 29 can absorb the dimensional error in the axial direction of the rotor core 23 and suppress the occurrence of burrs due to the dimensional error in the axial direction of the rotor core 23. it can.

  Of the resin layers 28 and 29, the resin layer on the side where the magnetic field generated from the magnet 25 is detected by the sensor 41 of the rotational position detection circuit (rotation angle detection means side, hereinafter also referred to as the detection surface side by the sensor). 28 is a thin layer 30 formed in a substantially annular shape in a plan view in a portion where the magnetic field is detected by the sensor 41 (a portion facing the sensor 41), and the thin layer 30 on the radially inner side thereof. Also has a thick layer 31 formed thick. Specifically, the thick layer 31 is formed to have a diameter smaller than half the diameter of the rotor 3, and the thin layer 30 is formed around the thick layer 31. That is, the thin layer 30 is formed on the outer peripheral side of the rotor 3 with respect to the magnet 25 accommodated in the slot 24 of the rotor 3. The thin layer 30 is formed thinner than the resin layer 29 on the opposite side of the rotor 3 from the side where the magnetic field is detected by the sensor 41.

  As described above, in the configuration in which the magnet 25 is sealed with the sealing resin 27, the thin film layer 30 is provided in a portion where the magnetic field of the magnet 25 is detected by the sensor 41, whereby the sensor 41 is opposed to the magnet 25. Can be disposed closer to each other, and the magnetic field of the magnet 25 can be reliably and accurately detected by the sensor 41. Therefore, the angular position of the rotor 3 can be reliably and accurately detected with the above-described configuration.

  Further, as described above, by providing the resin layer 28 with the thick layer 31, the thick layer 31 has a thin-walled channel cross-sectional area in the mold through which the sealing resin 27 melted at the time of injection molding flows. Since the flow resistance is larger than the layer 30, the sealing resin 27 melted from the resin layer 29 side (the side opposite to the side where the magnetic field is detected by the sensor) with respect to the rotor 3, as will be described later. In the case of injection, the flow of the sealing resin 27 toward the resin layer 28 can be improved. Thereby, insufficient filling of the sealing resin 27 into the mold can be prevented, the magnet 25 can be reliably sealed with the sealing resin 27, and the workability of the resin molding operation can be improved.

  The resin layer 29 has gate traces corresponding to the gate portions into which the molten sealing resin 27 is introduced into the molds 51 and 55 when the rotor 3 is sealed with the sealing resin 27. A portion 29a is formed (see FIG. 5). Further, as shown in FIG. 3B, the resin layer 29 is formed with a plurality of circular recesses 29b, 29b,. As shown in FIG. 5, when the molten sealing resin 27 is injected into the molding dies 51 and 55, the recess 29b causes the magnet 25 in the slot 24 of the rotor core 23 to be located by the injection pressure. It is formed by a tip portion of a levitation prevention pin 57 (second holding tool) disposed at a position separated from the magnet 25 by a predetermined distance so as not to rise above a certain amount.

  In the resin layer 28, a plurality of exposed portions 28a, 28a,... Where the surfaces of the rotor core 23 and the magnet 25 are exposed in a circular shape are formed. As will be described later, the exposed portion 28a includes a holding pin (not shown) that holds the rotor core 23 in the molds 51 and 55 when the rotor 3 is sealed with the sealing resin 27, It is formed by a holding pin 52 (holding tool) that holds the magnet 25 in the slot 24 of the rotor core 23. Thus, by providing the holding pin 52, when the magnet 25 is pushed to the holding pin 52 side by the injection pressure of the sealing resin 27 injected from the resin layer 29 side, the magnet 25 41 is reliably arranged at substantially the same position in the axial direction of the rotor 3 on the detection surface side 41, so that the magnet 25 can be reliably sealed with the sealing resin 27 in this state.

  In addition, since the resin layer 28 in this embodiment should just cover the whole magnet 25 as mentioned above, the outer peripheral end part of the rotor core 23 is exposed without being covered with the sealing resin 27. However, the present invention is not limited to this, and the entire rotor core 23 may be covered with the sealing resin 27.

-Manufacturing method of rotor-
A method for manufacturing the rotor 3 having the above-described configuration will be described below with reference to FIGS.

  First, a plurality of steel plates constituting the rotor core 23 are punched into a shape as shown in FIG. Then, the rotor core 23 is configured by laminating the respective steel plates in the thickness direction and caulking each other with the caulking portion 23e.

  Next, the magnets 25 are disposed in the slots 24 of the rotor core 23, respectively, and are disposed in the molds 51 and 55 for performing resin molding. As shown in FIGS. 5 and 6, these molds are constituted by a plurality of (for example, two) molds 51 and 55, and are attached so as to sandwich the rotor core 23 in the axial direction. At this time, a molding die 51 for molding the resin layer 28 on the detection surface side of the sensor 41 among the molding die is located below the magnet 25 and a molding die 55 for molding the resin layer 29 on the opposite side is the magnet 25. It arrange | positions so that it may be located above.

  Here, the forming die 51 has a holding pin (not shown) for holding the rotor core 23 and a holding pin 52 (holding tool) for holding the magnet 25 protruding from the surface of the die. Is provided. The molding die 55 includes a gate 56 as an inlet for injecting the sealing resin 27 into a space formed between the molding die 51 and the magnet 25 when the sealing resin 27 is injected. Is provided with a floating prevention pin 57 (second holding tool) for preventing the air from rising above a predetermined amount. The levitation prevention pin 57 is provided such that the tip portion is separated from the magnet 25 by a predetermined distance in a state where the magnet 25 is disposed in the molds 51 and 55. If the magnet 25 is sandwiched between the pins 52 and 57 in the injection process of the sealing resin 27, the magnet 25 can be fixed and molded together with the rotor core 23. The magnet 25 is usually made of a brittle material. Therefore, the magnet 25 may be damaged, or it may be difficult to place the magnet 25 in the molds 51 and 55 due to variations in the size of the magnet 25. On the other hand, as described above, the levitation prevention pin 57 is separated without being brought into contact with the magnet 25, thereby reliably preventing the magnet 25 from floating above the predetermined amount as described above. It is possible to prevent a problem from occurring. In the present embodiment, as shown in FIG. 5, the holding pins 52 and the anti-floating pins 57 are arranged so as to be lined up and down across the rotor core 23 and the magnet 25.

  Further, as shown in FIG. 6, the mold 51 is in contact with the non-covered portion 28 b on the inner and outer peripheral sides (only the outer peripheral side is shown in this drawing) of the axial end of the rotor 3. It arrange | positions so that only the thickness may be separated. The molding die 55 is arranged such that the thickness of the resin layer 29 formed at the end of the rotor 3 is larger than the thickness of the resin layer 28 formed by the molding die 51. That is, the mold 55 is formed so that the gap between the mold 3 and the end of the rotor 3 is larger than that of the mold 51. Thereby, the resin layer 28 formed at the end of the rotor 3 on the detection surface side of the sensor 41 can be made thinner than the thickness of the resin layer 29 formed at the end on the opposite side. In this way, by forming the molds 51 and 55 so that the thickness of the resin layer 29 on the gate 56 side is increased, the molten sealing resin 27 can easily flow from the gate 56 to the molds 51 and 55. In addition, by reducing the thickness of the resin layer 28 on the detection surface side of the sensor 41 of the rotor 3, the accuracy of detection of the magnetic field of the magnet 25 by the sensor 41 can be improved. The mold 51 is also provided with a step 51a so as to form the thin layer 30 and the thick layer 31 of the resin layer 28.

  As described above, the sealing resin 27 is injected from the gate 56 of the molding die 55 in a state where the rotor core 23 and the magnet 25 are arranged in the molding dies 51 and 55, whereby the magnet is generated by the injection pressure. 25 can be reliably sealed by the sealing resin 27 while being reliably positioned at substantially the same position in the axial direction of the rotor 3 on the detection surface side of the sensor 41.

  Here, the step of forming the rotor core 23 by superimposing the steel plates punched into the shape as shown in FIG. 4A is performed by the holding pins 52 in the forming dies 51 and 55 in the rotor core forming step. The process of injecting the molten sealing resin 27 from the gate 56 while holding the magnet 25 corresponds to the resin injection process.

-Effect of the embodiment-
As described above, in the configuration in which the magnet 25 is disposed inside the rotor 3, the entire magnet 25 is covered with the sealing resin 27, so that the rotation of the magnet 25 can be performed as compared with the conventional configuration in which a part of the magnet 25 is exposed. The magnet 25 can be more firmly held on the child 3. Moreover, at the end of the rotor 3 in the axial direction, the boundary portion of the sealing resin 27 is formed in a portion of the rotor core 23 without straddling the rotor core 23 and the magnet 25 (in the case of the resin layer 28). Or the boundary portion is not formed on the outer peripheral side, and almost the entire surface is covered with the sealing resin 27 (in the case of the resin layer 29). Resin protrusion (burrs) can be suppressed.

  In addition, the resin layer 28 at the end (the detection surface side of the sensor 41) detected by the sensor 41 of the rotational position detection circuit among the axial end portions of the rotor 3 is a thin layer 30 on the outer peripheral side. And a thick layer 31 on the inner peripheral side, and the thin layer 30 is formed smaller than the thickness of the resin layer 29 at the other end. 41 can detect the magnetic field of the magnet 25 reliably and accurately.

  In addition, the sensor 41 is arranged at a position that overlaps the magnet 25 in a plan view on the outer peripheral side of the rotor 3 with respect to the magnet 25 arranged radially in the rotor 3. Without being affected by the magnetic field of the entire rotor 3 or the magnetic field generated by the winding 13 of the stator 2, the magnetic field of the magnet 25 can be detected more accurately within the range where the magnet 25 exists. .

  Furthermore, when the rotor 3 is sealed with the sealing resin 27, the sealing resin 27 is injected from the side opposite to the detection surface side of the sensor 41, while the magnet 15 in the rotor 3 is Since it is held by the holding pin 52 from the detection surface side of the sensor 41, the magnet 25 is pressed against the holding pin 52 by the injection pressure of the sealing resin 27 and is sealed by the sealing resin 27 in that state. Therefore, since the plurality of magnets 25 can be sealed with the sealing resin 27 in a state where they are arranged so as to be substantially at the same position in the axial direction of the rotor 3 on the detection surface side of the sensor 41, the magnetic field of the magnets 25 is The sensor 41 can be detected with higher accuracy.

  Further, when the rotor 3 is sealed with the sealing resin 27 as described above, the detection of the sensor 41 of the magnet 25 is performed so that the magnet 25 does not float by a predetermined amount or more due to the injection of the sealing resin 27. By disposing the anti-levitation pin 57 at a predetermined distance from the magnet 25 on the opposite side of the surface, the magnet 25 is damaged by the pins 52 and 57 or is formed due to variations in the size of the magnet 25. It is possible to reliably prevent the magnet 25 from being lifted by a predetermined amount or more without deteriorating workability of the placement work in the molds 51 and 55.

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

  In the embodiment described above, the resin layer 28 including the thick layer 31 and the thin layer 30 is formed on the detection surface side of the sensor 41 in the rotor 3. May be formed.

  In the above embodiment, the magnet 25 is disposed in the slot 24 of the rotor core 23 and then attached to the molds 51 and 55. However, the present invention is not limited to this, and the rotor core 23 is mounted on the mold 51. , 55, the magnet 24 may be disposed in the slot 24 of the rotor core 23.

  Furthermore, in the above embodiment, the exposed portion 28a where the resin layer 28 is not formed is provided on the outer peripheral side of the axial end portion of the rotor 3, but this is not a limitation, and the entire surface of the rotor 3 is made of sealing resin. It may be covered.

  As described above, the present invention improves the holding power of the magnet by devising a configuration in which the rotor in which the magnet is disposed in the slot of the rotor core is sealed with the sealing resin. Since generation | occurrence | production of the burr | flash of sealing resin can be suppressed as much as possible, it is especially useful for the motor provided with the mold rotor, for example.

It is a longitudinal section showing a schematic structure of a motor concerning an embodiment of the present invention. It is a perspective view which shows schematic structure of a rotor. 3A is a cross-sectional view of the rotor taken along line IIIa-IIIa in FIG. 2, and FIG. It is the (A) top view of a rotor core, and the IVb-IVb line sectional drawing in (B) (A). It is a partial expanded sectional view which expands and shows the state of the magnet part after injecting sealing resin with respect to a rotor. It is a partial expanded sectional view which expands and shows the state of the rotor core part after injecting sealing resin with respect to a rotor. It is a partial expanded sectional view which expands and shows the holding structure of a board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Stator 3 Rotor 21 Shaft part 23 Rotor core 24 Slot 25 Magnet 27 Sealing resin 28 Resin layer 28a Exposed part 28b Uncovered part 29 Resin layer 29a Gate trace part 29b Recessed part 30 Thin layer 31 Thick layer 41 Sensor (Rotation angle detection means)
51, 55 Mold 52 Holding pin (holding tool)
57 Anti-floating pin (second holder)
P axis

Claims (10)

A rotor at least partially sealed with a sealing resin so that the magnets are respectively held in a plurality of slots formed in a substantially cylindrical rotor core; and an axially outward direction of the rotor A rotation angle detecting means that is arranged and detects an angular position of the rotor based on a magnetic field generated from the magnet,
The motor is characterized in that the range including at least the magnet is sealed with the sealing resin when the end of the rotation angle detection means side is viewed from the axial direction of the rotor. In claim 1,
In the rotor, a resin layer made of the sealing resin is formed on the outer surface of both axial end portions,
In the rotor, the thickness of the resin layer at the portion where the magnetic field is detected by the rotation angle detection means is thinner than the thickness of the resin layer at the axial end opposite to the rotation angle detection means side of the rotor. A motor characterized by that. In claim 2,
In the rotor, the molten sealing resin is injected from the end of the mold opposite to the rotation angle detecting means side in a state where the rotor core and the magnet are arranged in the mold. The motor is sealed with the sealing resin by being solidified. In any one of Claim 1 to 3,
In the rotor, the thickness of the resin layer in the portion where the magnetic field is detected by the rotation angle detection means at the end on the rotation angle detection means side is thinner than the thickness of the resin layer in other portions. Motor. In any one of Claims 1-4,
In the rotor, the rotor core and the magnet are arranged in a mold, and the magnets in the plurality of slots are arranged at the same axial position at the end of the rotor on the rotation angle detection means side. The molten sealing resin is injected from the end of the mold opposite to the rotation angle detection means side and solidified while being held by the holder, and sealed by the sealing resin. A motor characterized by being stopped. In claim 5,
In the rotor, an exposed portion is formed at an end portion on the rotation angle detection means side so that a portion held by the holder is exposed without being covered with sealing resin, and the rotation angle detection means A motor is characterized in that a gate mark portion is formed as an inlet portion when the sealing resin is injected into the resin layer provided at the end opposite to the side. In claim 5 or 6,
The rotor is separated from the end by a predetermined distance in the axial direction when the sealing resin is injected into the resin layer provided at the end opposite to the rotation angle detecting means. A motor is characterized in that a recess is formed by the tip of the second holder arranged so as to. In any one of Claims 1-7,
The rotor core is formed by laminating a plurality of steel plates. In any one of Claims 1-8,
The motor according to claim 1, wherein the rotation angle detection means is arranged so as to overlap the magnet on the rotor outer peripheral side of the magnet when viewed from the axial direction of the rotor. A rotor at least partially sealed with a sealing resin so that the magnets are respectively held in a plurality of slots formed in a substantially cylindrical rotor core; and an axially outward direction of the rotor A rotation angle detection means for detecting an angular position of the rotor based on a magnetic field generated from the magnet, and a method of manufacturing a motor,
A rotor core forming step of forming the rotor core by laminating a plurality of steel plates formed with slot portions constituting the slot;
In the slot of the rotor core, the entire rotation angle detection means side of the magnet is covered with the sealing resin, and the magnet is arranged at the same position in the axial direction of the rotor on the rotation angle detection means side. In this way, the resin injection is performed by injecting the sealing resin from the side opposite to the rotation angle detecting means side with respect to the rotor core and the magnet arranged in the mold while holding the plurality of magnets by the holder. And a process for producing a motor.

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