JP2011151909A - Core for rotors and rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core for rotors and a rotor for motors that are obtained by pressure-forming a mixture of magnetic powder and binder, wherein mechanical strength is ensured to suppress breakage and increase in iron loss and cost reduction is achieved. <P>SOLUTION: A dust core 1 includes a yoke portion 1b having a center hole 1a into which a rotating shaft 2 is press fit, multiple winding barrel bodies 1c that are provided on the outer circumferential surface 1bo of the yoke portion 1b and on which a wire is wound, and tooth portions 1d provided in 1co outside of the winding barrel bodies 1c in the radial direction. The dust core is formed by pressure-forming a mixture of magnetic powder and binder. The yoke portion 1b is set to any of the following temperature distributions and heated and bonded: a first temperature pattern in which temperature is gradually lowered from the inner circumferential surface 1bi to the outer circumferential surface 1bo of the yoke portion 1b in the radial direction; a second temperature pattern in which temperature is lowered stepwise; and a third temperature pattern obtained by combining the first temperature pattern and the second temperature pattern. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotor core and a rotor used in a motor.

  As shown in FIG. 16, as a rotor core (core) of a conventional motor, as shown in FIG. 16, a rotating shaft 103, a connecting member 102 fixed to the rotating shaft 103, and a center hole 105 into which an outer peripheral surface of the connecting member 102 is press-fitted. An armature 100 of a direct current motor (not shown) is disclosed that includes a core 101 formed with a connecting member 102 and a commutator 104 disposed on the upper end surface in FIG. The core 101 includes a first core part 110 and a second core part 120 having the same shape and the same dimensions as the first core part 110. 17 is a plan view of the first core part 110 of FIG. 16, and FIG. 18 is a cross-sectional view of the FF of FIG. 19 is a plan view of the second core portion 120 of FIG. 16, and FIG. 20 is a GG cross-sectional view of FIG.

  As shown in FIGS. 17 and 18, the first core portion 110 includes a ring portion 111 and a plurality of teeth portions 112 provided equally on the outer peripheral surface 113 of the ring portion 111, and the teeth portion 112 is wound around the teeth portion 112. The wire 130 is wound. As shown in FIG. 19 and FIG. 20, the second core portion 120 includes a ring portion 121 and a plurality of teeth portions 122 equally provided on the outer peripheral surface 123 of the ring portion 121. The wire 130 is wound.

  Then, the first core part 110 and the second core part 120 in which the windings 130 are wound around the tooth parts 112 and 122 are opposed to each other, and the positions in the axial direction are matched so that the tooth parts 112 and 122 overlap each other. Let Further, the first core portion 110 and the second core portion 120 are assembled to each other in a state where the positions of the tooth portions 112 and 122 are shifted by 45 degrees in the circumferential direction. At this time, the ring part 111 in the first core part 110 is fitted inside the ring part 121 in the second core part 120, and the ring part 121 in the second core part 120 is inside the ring part 111 in the first core part 110. It is inserted.

  More specifically, the outer peripheral surface 113 (FIG. 17) of the ring part 111 in the first core part 110 and the inner side surface 124 (FIG. 20) of the ring part 121 in the second core part 120 are brought into contact with each other. It is fixed with an adhesive or the like. On the other hand, the outer peripheral surface 123 (FIG. 19) of the ring part 121 in the second core part 120 and the inner side surface 114 (FIG. 18) of the ring part 111 in the first core part 110 are brought into contact with each other, and the contact part is an adhesive. It is fixed by etc.

As shown in FIG. 16, the first core portion 110 and the second core portion 120 are integrated to form a center hole formed by the center hole 115 of the first core portion 110 and the center hole 125 of the second core portion 120. The connecting member 102 is press-fitted into 105. Further, the shaft 103 is press-fitted into a through hole 106 provided in the central portion of the connecting member 102. (For example, refer to Patent Document 1.)
Also disclosed is a motor rotor obtained by molding magnetic particles whose surfaces are coated with an insulating material, having magnets disposed therein, and having a cylindrical reinforcing layer on the outer periphery thereof. In this motor rotor, the brittleness, which is a weak point of the dust magnetic material, is reinforced by the reinforcing layer provided on the outer periphery thereof. As a result, the mechanical strength of the rotor is improved, and breakage and scattering due to impact (rapid rotation, rapid braking, etc.) and large centrifugal force during high-speed rotation are prevented (for example, see Patent Document 2).

  An electric motor stator comprising a plurality of teeth, a coil wound around each of the plurality of teeth, and a yoke having a fitting hole for fitting the teeth, the teeth being a pressure containing a magnetic material. Includes a teeth body formed of a powder magnetic core material and a teeth reinforcement material having higher mechanical strength than the teeth body. The teeth reinforcement material is integrally formed on at least a part of the surface of the teeth body, and the yoke is fitted. An electric motor stator is disclosed in which a tooth is fitted to a yoke so that a wall surface of a hole and a tooth reinforcing material are in contact with each other. More specifically, the teeth body has a substantially T-shape, and a teeth head portion (a portion facing the rotor of the electric motor) that is a portion extending above the T shape, and a portion protruding below the T shape. And a teeth bottom. In the teeth, the teeth reinforcing material and the teeth main body are integrally formed so that the entire end surface of the bottom portion of the teeth is covered with the teeth reinforcing material. The yoke is formed in a cylindrical shape by laminating ring-shaped steel plates made of steel (see, for example, Patent Document 3).

  A plurality of split cores each having a tooth with a coil and a yoke portion provided at one end of the tooth are arranged in an annular shape, and the yoke portions of the split coils are connected to form a stator of the motor. A shrink-fit ring and a stator that are shrink-fit rings that are shrink-fitted to the outer periphery of each split core and that have at least a plurality of through holes in the circumferential direction are disclosed. The split core is formed by compacting. For example, the surface of pure iron powder is insulated with an inorganic insulator, mixed with a small amount of an organic resin binder, and then compacted (see, for example, Patent Document 4). .)

Japanese Patent No. 3920740 JP 2005-318760 A JP 2007-325362 A JP 2008-86172 A

  However, according to Patent Document 1, in order to reduce the iron loss, the first core part 110 and the second core part 120 are manufactured by mixing the magnetic powder and the resin binder and performing pressure molding. The core 101 composed of the part 110 and the second core part 120 is fragile. Therefore, when the connecting member 102 is press-fitted into the center hole 105 formed by the center holes 115 and 125 of the ring portions 111 and 121 of the core 101 (the first core portion 110 and the second core portion 120), There is a problem that is easy to break. Moreover, when the temperature of the core 101 at the time of pressure molding is increased in order to ensure the strength of the core 101, there is a problem that the iron loss of the core 101 increases.

  Further, according to Patent Document 2, the motor rotor is improved in brittleness, which is a weak point of the powder magnetic material, by the reinforcing layer provided on the outer peripheral portion thereof, but since the central hole is not reinforced, the motor rotor When the rotary shaft is press-fitted into the center hole provided at the center of the shaft, the vicinity of the center hole may be damaged. Further, when the motor rotates, the vicinity of the center hole may be damaged by the centrifugal force generated in the motor rotor. A method of fixing the adhesive by inserting the rotation shaft coated with the adhesive into the center hole is also conceivable, but there is a problem that the number of bonding steps increases and the cost of the motor rotor increases.

  Further, according to Patent Document 3, the teeth reinforcing material provided at the teeth bottom portion of the teeth and the side surface of the fitting hole formed in the yoke are fitted so as to be in contact with each other, and the teeth formed by the powder magnetic core material are used. The surface of the main body is protected by a tooth reinforcing material. As a result, when the teeth are fitted into the fitting holes of the yoke, damage to the surface of the teeth is suppressed, but the number of teeth reinforcing material parts is required for the number of teeth, which increases the cost of the motor stator. There is.

  Further, according to Patent Document 4, the stator using the shrink-fit ring is tightened with the predetermined tightening force by the shrink-fit ring having a penetration, so even if the split core is used as a green compact, The stator will not be damaged. However, a heating process for shrink fitting is required, and the shrink fitting ring is provided with a plurality of through holes at least in the circumferential direction, which increases the cost of the shrink fitting ring. There is a problem that becomes high.

  The present invention has been made in view of the above problems, and is a rotor core and a rotor of a motor for mixing and pressing magnetic powder and a binder, and mechanically suppressing the breakage. An object of the present invention is to provide an iron core for a rotor and a rotor that are low in cost while suppressing an increase in iron loss while ensuring strength.

  The first problem-solving means taken to solve the above problems is a yoke part in which a central hole capable of press-fitting a rotation shaft is formed in the inner peripheral part, and a winding projecting from the outer peripheral part of the yoke part. A rotor core including a plurality of rotatable winding body portions and a tooth portion provided on a radially outer side of each winding body portion, the rotor core including a magnetic powder and a binder The yoke part has a first temperature pattern in which the temperature gradually decreases in the radial direction from the inner peripheral part to the outer peripheral part, and the yoke part has a step in the radial direction from the inner peripheral part to the outer peripheral part. In other words, heat bonding is performed with a temperature distribution of any one of a second temperature pattern in which the temperature is lowered and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined.

  Further, the second problem solving means is that the winding body portion and the tooth portion are a first temperature pattern in which the temperature gradually decreases in the radial direction from the radially inner side to the radially outer side, from the radially inner side to the radial direction. Heat bonding is performed with a temperature distribution of any one of a second temperature pattern in which the temperature is lowered stepwise in the radial direction leading to the outside and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. That's it.

  Further, the third problem solving means is provided on the outer side in the radial direction of each of the winding body parts, the yoke part, a plurality of winding body parts protruding from the outer periphery of the yoke part and capable of winding the windings. A rotor core including a tooth portion and a rotating shaft provided at a central portion of the yoke portion, wherein the rotor is formed by press-molding magnetic powder and a binder. The rotary shaft and the yoke portion are formed, a first temperature pattern in which the temperature gradually decreases in the radial direction from the central axis of the rotary shaft to the outer peripheral portion of the yoke portion, from the central axis of the rotary shaft to the outer peripheral portion of the yoke portion By heat-bonding at any one temperature distribution among the second temperature pattern in which the temperature is lowered stepwise in the radial direction and the third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. is there.

  The fourth problem solving means is that the winding body portion and the tooth portion are a first temperature pattern in which the temperature gradually decreases in the radial direction from the radially inner side to the radially outer side, from the radially inner side to the radial direction. Heat bonding is performed with a temperature distribution of any one of a second temperature pattern in which the temperature is lowered stepwise in the radial direction leading to the outside and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. That's it.

  According to the present invention, each location along the radial direction from the inner peripheral portion of the yoke portion to the outer peripheral portion of the yoke portion has the first temperature pattern in which the temperature gradually decreases and the second temperature in which the temperature gradually decreases. The temperature distribution is set to any one of the temperature patterns and the third temperature pattern in which the first temperature pattern and the second temperature pattern are combined, and is bonded by heating. In general, when pressure-molding powder using a binder, the bonding strength between the particles constituting the powder depends on the heating temperature, so after heat-bonding, the yoke part radially outside the yoke part radially outside The mechanical strength of each location along the radial direction leading to the first strength distribution that gradually decreases, the second strength distribution that gradually decreases, the first strength distribution and the second strength distribution are combined The mechanical strength of any one of the third strength distributions is obtained. Accordingly, since the mechanical strength in the vicinity of the yoke portion in the radial direction is higher than that in other portions of the yoke portion, when the rotary shaft is press-fitted into the center hole, the vicinity of the yoke portion in the radial direction and the inner peripheral surface of the center hole is provided. Damage is suppressed. Further, when the motor rotates, the closer to the inner peripheral surface of the yoke portion from the outer side in the radial direction of the yoke portion, the higher the stress of the rotor core caused by centrifugal force, but the first strength distribution, second strength distribution, third Since the mechanical strength is higher due to the strength distribution, the damage around the central hole of the yoke portion is suppressed.

  In addition, the electrical resistance at each location along the radial direction from the radially inner side of the yoke part to the radially outer side of the yoke part after molding and bonding is gradually increased by the temperature of the yoke part described above and the first resistance distribution. The electrical resistance of any one of the resistance distributions among the second resistance distribution that increases stepwise and the third resistance distribution in which the first resistance distribution and the second resistance distribution are combined is obtained. Therefore, the closer to the inner side of the yoke part from the radial outer side of the yoke part, the electric resistance decreases, but the magnetic flux density due to the alternating magnetic flux of the yoke part during motor rotation also decreases. The increase of is suppressed.

  Further, in the second problem solving means, the winding trunk portion and the tooth portion along the radial direction from the radially inner side of the winding trunk portion to the radially outer side of the teeth portion during or after the pressure molding. Each of the locations includes a first temperature pattern in which the temperature gradually decreases, a second temperature pattern in which the temperature gradually decreases, and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. It is set to any one of the temperature distributions and is heat bonded. As a result, the mechanical strength of the winding body part and the tooth part along the radial direction from the radially inner side of the winding body part to the radially outer side of the tooth part is gradually reduced, and stepwise The mechanical strength of any one of the second intensity distribution and the third intensity distribution obtained by combining the first intensity distribution and the second intensity distribution is obtained. And the closer to the radially inner side of the winding body part from the radially outer side of the teeth part, the higher the stress of the winding body part and the teeth part caused by the centrifugal force during motor rotation, the first, second, second The mechanical strength is also increased by the three strength distribution, so that the winding body portion and the tooth portion are prevented from being damaged.

  In addition, the electrical resistance of the winding body part and the tooth part along the radial direction from the radially inner side of the winding body part to the radially outer side of the tooth part gradually increases depending on the temperature of the winding body part and the tooth part. The electrical resistance of any one of the first resistance distribution, the second resistance distribution that increases stepwise, and the third resistance distribution that is a combination of the first resistance distribution and the second resistance distribution is obtained. It is done. In each place of the winding body part and the tooth part, the magnetic flux density due to the alternating magnetic flux is higher than that in the vicinity of the radially inner side of the yoke part. However, the closer to the radially inner side of the winding body portion from the radially outer side of the teeth portion, the electric resistance decreases due to the first, second, and third resistance distributions, and the electric power near the radially inner side of the winding body portion is reduced. Since the resistance is higher than the electric resistance in the vicinity of the radially inner side of the yoke portion, an increase in iron loss between the winding body portion and the tooth portion is suppressed. As a result, an increase in each iron loss in the winding body portion, the tooth portion, and the yoke portion is suppressed, and a rotor core in which an increase in iron loss is suppressed can be provided. As described above, it is possible to provide a rotor core in which an increase in iron loss is suppressed while ensuring mechanical strength that suppresses damage to the rotor core.

  Furthermore, the rotor iron core does not require a reinforcing member for preventing breakage, and the number of parts is reduced, so that the cost is reduced.

  In addition, the rotor is configured by press-fitting a rotation shaft into the center hole of the rotor core. Therefore, a rotor core suitable for multiple types of rotation shafts can be used, and a versatile rotor core can be used. An iron core can be provided.

  Further, in the third problem solving means, the rotating shaft and the yoke portion are set to a temperature of any one of the first temperature pattern, the second temperature pattern, and the third temperature pattern, and are bonded by heating. The Therefore, after molding and bonding, each location along the radial direction from the axis of the rotating shaft to the radially outer side of the yoke portion in the rotating shaft and the yoke portion gradually decreases with the first strength distribution gradually decreasing. The mechanical strength of any one of the second strength distribution and the third strength distribution obtained by combining the first strength distribution and the second strength distribution is obtained. As the motor rotates, the stress at each location generated by the centrifugal force of the rotor increases as it approaches the axis of the rotating shaft from the radially outer side of the rotating shaft and the yoke portion. Since the mechanical strength is higher due to the strength distribution, the breakage of the rotating shaft and the yoke portion can be suppressed.

  In addition, after molding and bonding, each location of the yoke portion along the radial direction from the yoke portion axis to the outside in the radial direction of the yoke portion is gradually increased, and the second resistance distribution is gradually increased. And the electrical resistance of any one of the third resistance distributions obtained by combining the first resistance distribution and the second resistance distribution is obtained. Therefore, as the motor rotates, the magnetic flux density at each location of the yoke portion generated by the alternating magnetic flux increases as it approaches the outer side in the radial direction of the yoke portion from the shaft of the yoke portion. Since the resistance is also increased, an increase in the iron loss of the yoke portion is suppressed.

  In the fourth problem solving means, at the time of molding, the winding body part and the tooth part are set to any one of the temperature distribution of the first temperature pattern, the second temperature pattern, and the third temperature pattern. And heat-bonded. Therefore, after molding and bonding, each location along the radial direction from the radially inner side of the winding trunk portion to the radially outer side of the teeth portion in the winding trunk portion and the teeth portion is gradually reduced as the first strength distribution. The mechanical strength of any one of the second intensity distribution that gradually decreases and the third intensity distribution obtained by combining the first intensity distribution and the second intensity distribution is obtained. And, in the winding body part and the tooth part, the closer to the radially inner side of the winding body part from the radially outer side of the tooth part, the higher the stress in each place caused by the centrifugal force of the rotor, The mechanical strength is also increased by the second and third strength distributions, so that the winding body portion and the tooth portion can be prevented from being damaged. As described above, damage to the rotating shaft, the yoke portion, the winding body portion, and the tooth portion is suppressed, so that damage to the rotor can be suppressed.

  In addition, after forming and bonding, each location along the radial direction from the radially inner side of the winding body part to the radially outer side of the tooth part in the winding body part and the tooth part gradually increases with the first resistance distribution. The electric resistance indicated by any one of the second resistance distribution that increases stepwise and the third resistance distribution that combines the first resistance distribution and the second resistance distribution is obtained.

  When the motor rotates, the magnetic flux density at each location generated by the alternating magnetic flux between the winding body portion and the tooth portion is higher than the magnetic flux density due to the alternating magnetic flux near the center of the yoke portion. However, the electrical resistance of each part of the winding body part and the teeth part increases from the radially inner side of the winding body part to the radially outer side of the teeth part due to the first, second, and third resistance distributions, and the yoke. It is higher than the electrical resistance near the center of the part. Therefore, an increase in iron loss at the winding body and the tooth portion is suppressed. As described above, it is possible to provide a rotor in which an increase in iron loss is suppressed while ensuring mechanical strength capable of suppressing damage to the rotor.

  Furthermore, since the rotor core and the rotating shaft are integrally formed in the rotor, there is no need to press-fit the rotating shaft into the rotor core, and there is no need for reinforcing members to prevent breakage and the number of parts is reduced. And low cost.

1 is a perspective view of a powder core according to Example 1. FIG. It is a perspective view of the rotating shaft press-fitted in the dust core of FIG. 1 is a perspective view of a rotor according to Embodiment 1. FIG. It is MM sectional drawing of FIG. It is a figure which shows the LL sectional drawing of FIG. 1, and the temperature of the powder core at the time of pressure molding. It is a figure which shows the mechanical strength of the dust core in the dust core temperature of FIG. It is a figure which shows the electrical resistance of the dust core in the dust core temperature of FIG. It is a figure which shows the other temperature of the dust core at the time of the press molding in LL sectional drawing of FIG. It is a figure which shows the mechanical strength of the dust core in the dust core temperature of FIG. It is a figure which shows the electrical resistance of the dust core in the dust core temperature of FIG. It is a figure which shows the other temperature of the dust core at the time of the press molding in LL sectional drawing of FIG. It is a figure which shows the mechanical strength of the dust core in the dust core temperature of FIG. It is a figure which shows the electrical resistance of the dust core in the dust core temperature of FIG. 6 is a perspective view of a rotor according to Embodiment 2. FIG. It is NN sectional drawing of FIG. It is sectional drawing of the armature provided with the core of a prior art. It is a top view of the 1st core of FIG. It is FF sectional drawing of FIG. It is a top view of the 2nd core of FIG. It is GG sectional drawing of FIG.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  1 is a perspective view of a dust core according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of a rotating shaft of a motor. FIG. 3 is a perspective view of the rotor according to the first embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line MM in FIG.

  As shown in FIG. 1, a dust core (rotor core) 1 includes a yoke portion 1b (in the range indicated by an arrow P) having a center hole 1a at the center of the dust core 1, and an outer peripheral surface of the yoke portion 1b. A plurality of (for example, three) winding body portions 1c (in the range of arrows Q) equally provided on 1bo (FIG. 4) and outer peripheral surfaces (outside in the radial direction) of the respective winding body portions 1c. ) An arc-shaped tooth portion 1d (range of arrow R) provided at 1co (FIG. 4). The dust core 1 is formed by coating an insulating material on the surface of a magnetic powder (for example, a soft magnetic powder having a diameter of about 0.2 mm), and press-molding the coated magnetic powder and a binder. . At this time, the insulating material films of the adjacent magnetic powders are bonded to each other, and a binder such as a resin material flows in a gap formed by the adjacent magnetic powders to adhere the magnetic powder. As shown in FIG. 4, a part of the outer peripheral surface 1bo of the yoke portion 1b forms an inner peripheral surface (radially inner side) 1ci of the winding body portion 1c, and the outer peripheral surface 1co of the winding body portion 1c is a tooth portion 1d. A part of the inner peripheral surface 1di is formed. Further, an inner peripheral surface (radially inner side) 1bi of the yoke portion 1b is a common inner peripheral surface of the yoke portion 1b and the center hole 1a.

  At the time of pressure molding, each location of the yoke portion 1b along the radial direction from the inner peripheral surface 1bi to the outer peripheral surface 1bo is stepwise with a first temperature pattern (FIG. 5A) in which the temperature is gradually lowered. The temperature distribution is set to any one of a second temperature pattern (FIG. 8) in which the temperature is lowered and a third temperature pattern (FIG. 11) in which the first temperature pattern and the second temperature pattern are combined.

  Furthermore, at the time of pressure molding, the winding body portion along the radial direction from the inner peripheral surface 1ci of the winding body portion 1c (the outer peripheral surface 1bo of the yoke portion 1b) to the outer peripheral surface (radially outer side) 1do of the teeth portion 1d. Each location of 1c and teeth part 1d has a first temperature pattern (FIG. 5B) in which the temperature gradually decreases, a second temperature pattern (FIG. 8) in which the temperature gradually decreases, and a first temperature pattern. And a third temperature pattern (FIG. 11) in which the second temperature pattern is combined.

  By the way, the inner diameter of the center hole 1a of the dust core 1 is slightly smaller than the outer diameter of the rotating shaft 2 (FIG. 2), and the rotor 2 has the center hole 1a of the dust core 1 as shown in FIGS. The rotor 3 is constituted by the dust core 1 and the rotating shaft 2.

  A winding (not shown) is wound around the winding body 1 c of the powder core 1. The dust core 1 is inserted so that the outer peripheral surface 1do of the tooth portion 1d faces the inner peripheral surface of the stator (not shown) with a predetermined gap, and both ends of the rotary shaft 2 are bearings (see FIG. (Not shown) is rotatably supported.

  The central hole 1a into which the rotary shaft 2 is press-fitted is a through hole, but may be a hole with one end closed. In this case, one end side of the rotating shaft is attached to the bearing, and the other end side is press-fitted into the center hole of the dust core 1.

  Next, the operation and effect of the dust core 1 according to Example 1 of the present invention will be described. When heat is applied to magnetic powder that has not been coated with an insulating material on the surface, the contact surface between the magnetic powders is diffusion bonded and the mechanical strength between the magnetic powders increases. The electric resistance value between them becomes low. When magnetic powder with a coating of insulating material on the surface and a binder are mixed and heat-pressed to form, it is generally due to the presence of an insulating coating compared to the diffusion bonding of magnetic powders described above. The mechanical strength decreases, but the electrical resistance increases. In this case, the values of mechanical strength and electrical resistance depend on the temperature of the dust core 1 during pressure molding (hereinafter, core temperature). When the core temperature is increased, the thickness of the contact portion between the magnetic particles having an insulating coating on the surface is reduced, and the contact area of the coating portion between the magnetic particles is increased. This increases the mechanical strength between the magnetic particles, but decreases the electrical resistance. On the other hand, when the core temperature is lowered, the film thickness of the contact part between the magnetic particles with the insulating film applied on the surface is substantially the same as the film thickness before pressure molding, and the contact area of the film part between the magnetic particles. Decreases, the electrical resistance between the magnetic particles increases, but the mechanical strength between the magnetic particles decreases. Also, if the core temperature is too high, the insulating film on the surface of the magnetic particles is broken and the metal of the magnetic particles is diffusion bonded, and the mechanical strength between the magnetic particles is greatly increased, but the electrical resistance between the magnetic particles is It drops significantly. If the core temperature is too low, a large amount of a binder made of a resin material flows between magnetic particles coated with an insulating film, and the distance between the magnetic particles increases, and the electrical resistance value and the magnetic resistance increase remarkably. The mechanical strength is significantly reduced.

  Therefore, at the time of pressure molding, in the dust core 1, a place where a high electrical resistance is required even if the mechanical strength is somewhat low, a high mechanical strength is obtained even if the core temperature is appropriately lowered and the electrical resistance value is somewhat low. Where the temperature is required, the core temperature is appropriately increased. Therefore, the dust core 1 of Example 1 has an appropriate temperature at each location of the dust core 1 at the time of pressure molding so that the mechanical strength and electrical resistance at each location are appropriate after the pressure molding. Set to

  (A) of FIG. 5 is LL sectional drawing of FIG. 1, (b) is a figure which shows the temperature distribution of the powder core 1 at the time of pressure molding. In the figure, O indicates the center position of the center hole 1 a, and A, B, C, and D indicate the radial positions of the dust core 1. The temperature of the powder core 1 during the pressure molding is gradually lowered from the inner peripheral surface 1bi of the yoke portion 1b toward the outer peripheral surface 1bo of the yoke portion 1b on the left side of the Z axis Z in FIG. Then, on the right side of the Z-axis Z in FIG. 5A, the yoke portion 1b is gradually lowered from the inner peripheral surface 1bi through the yoke portion 1b and the winding body portion 1c toward the outer peripheral surface 1do of the tooth portion 1d. (First temperature pattern).

  6 and 7 show the distribution of mechanical strength and the electrical resistance in the LL cross-sectional view (FIG. 5 (a)) of the dust core 1 that has been pressure-molded under the core temperature distribution shown in FIG. 5 (b). It is a figure which shows distribution.

  As shown in FIG. 6, by pressing with the above-described first temperature pattern, the inner peripheral surface 1bi of the yoke portion 1b passes through the outer peripheral surface 1bo and the outer peripheral surface 1bo toward the outer peripheral surface 1do of the tooth portion 1d. Thus, the mechanical strength at each location of the dust core 1 gradually decreases (first strength distribution). Therefore, since the mechanical strength is high in the vicinity of the inner peripheral surface 1bi of the yoke portion 1b, breakage of the vicinity of the inner peripheral surface 1bi of the yoke portion 1b and the central hole 1a is suppressed when the rotary shaft 2 is press-fitted into the central hole 1a. The

  Moreover, although the stress of each place of the dust core 1 resulting from the centrifugal force generated at the time of motor rotation increases from the outer peripheral surface 1do of the tooth portion 1d toward the inner peripheral surface 1bi of the yoke portion 1b, the dust core 1 Since the mechanical strength increases as it approaches the inner peripheral surface 1bi of the yoke portion 1b, the first strength distribution suppresses breakage of the dust core 1 due to centrifugal force.

  Further, during the motor operation, alternating magnetic flux alternately flows in and out between the tooth portion 1d of the dust core 1 and the teeth portion (not shown) of the stator (not shown). And the alternating magnetic flux which flowed into the teeth part 1d of the dust core 1 in the half cycle passes through the winding body part 1c, the yoke part 1b, and the adjacent winding body part 1c, and is adjacent to it. From the tooth portion 1d to the tooth portion adjacent to the stator, and in the next half cycle, the alternating magnetic flux flows in the opposite direction.

  By the way, the alternating magnetic flux flowing through the dust core 1 generates an induced current in the dust core 1 and causes iron loss. However, the lower the electrical resistance of the dust core 1, the more the induced current increases and the induced current increases. The iron loss increases as you do it. With the first temperature pattern described above, as shown in FIG. 7, the electrical resistance at each location gradually decreases from the outer peripheral surface 1bo of the yoke portion 1b toward the inner peripheral surface 1bi, and further passes through the inner peripheral surface 1bi. The electrical resistance at each location gradually increases toward the outer peripheral surface 1do of the tooth portion 1d (first resistance distribution). Therefore, in the yoke portion 1b, the magnetic flux density due to the alternating magnetic flux of the yoke portion 1b decreases as it approaches the inner peripheral surface 1bi of the yoke portion 1b, so that an increase in iron loss of the yoke portion 1b is suppressed.

  Further, the magnetic flux density due to the alternating magnetic flux flowing through the winding body portion 1c and the tooth portion 1d is higher than the magnetic flux density due to the alternating magnetic flux in the vicinity of the inner peripheral surface 1bi of the yoke portion 1b. However, since the electrical resistance at each location of the winding body portion 1c and the tooth portion 1d is larger than the electrical resistance in the vicinity of the inner peripheral surface 1bi of the yoke portion 1b, the increase in iron loss of the winding body portion 1c and the tooth portion 1d is not increased. It is suppressed. By the above, the increase in the iron loss of the yoke part 1b, the coil | winding trunk | drum 1c, and the teeth part 1d is suppressed, and the increase in the iron loss of the dust core 1 is suppressed.

  FIG. 8 shows a second temperature pattern in which the temperature of the dust core 1 is lowered stepwise during pressure molding in the radial direction from the inner peripheral surface 1bi of the yoke portion 1b to the outer peripheral surface 1do of the teeth portion 1d. It is a figure which shows the temperature distribution of the dust core 1 of LL sectional drawing (FIG. 5 (a)). 9 and 10 show the mechanical strength distribution of the LL cross-sectional view (FIG. 5 (a)) of the dust core 1 after pressure molding under the dust core temperature distribution of FIG. It is a figure which shows distribution. As shown in FIGS. 9 and 10, the mechanical strength of the dust core 1 gradually decreases from the inner peripheral surface 1bi of the yoke portion 1b toward the outer peripheral surface 1bo and the outer peripheral surface 1do of the teeth portion 1d. (Second intensity distribution), the electrical resistance increases stepwise (second resistance distribution). The action and effect of the dust core 1 in this case are the same as those of the dust core 1 having the mechanical strength of FIG. 6 and the electrical resistance of FIG. Note that A, B, C, D, and O in FIGS. 8 to 10 indicate A, B, C, D, and O in FIG.

  FIG. 11 shows the first temperature pattern in which the temperature of the dust core 1 is gradually lowered during pressure molding in a radial direction from the inner peripheral surface 1bi of the yoke portion 1b to the outer peripheral surface 1do of the tooth portion 1d. It is a figure which shows the temperature distribution of the dust core 1 of LL sectional drawing (FIG. 5 (a)) of the 3rd temperature pattern which combined with the 2nd temperature pattern to lower to 2nd. 12 and 13 show the mechanical strength distribution and the electrical resistance distribution in the LL cross-sectional view (FIG. 5 (a)) of the dust core 1 after pressure molding under the core temperature distribution of FIG. FIG. As shown in FIGS. 12 and 13, the mechanical strength of the dust core 1 is gradually and gradually stepped from the inner peripheral surface 1bi of the yoke portion 1b toward the outer peripheral surface 1bo and the outer peripheral surface 1do of the teeth portion 1d. Then, it gradually decreases again (third strength distribution), and the electric resistance gradually increases, then gradually and again (third resistance distribution). The action and effect of the dust core 1 in this case are the same as those of the dust core 1 having the mechanical strength of FIG. 6 and the electrical resistance of FIG. In addition, A, B, C, D, and O in FIGS. 11 to 13 indicate A, B, C, D, and O in FIG.

  Further, the dust core 1 does not require a reinforcing member for preventing breakage, and the number of parts is reduced, so that the cost is reduced.

  Moreover, since the rotor 3 is configured by press-fitting the rotary shaft 2 into the center hole 1a of the dust core 1, the dust core 1 can be used with respect to a plurality of types of rotary shafts, and versatile dust. The core 1 can be provided.

  FIG. 14 is a perspective view of a rotor according to Embodiment 2 of the present invention, and FIG. 15 is a cross-sectional view taken along line NN in FIG. As shown in FIGS. 14 and 15, the rotor 13 includes a dust core 11 (rotor core) and rotary shafts 12 and 12 provided at both ends of the dust core 11, and an insulating material is coated on the surface. The magnetic material powder (for example, soft magnetic powder having a diameter of about 0.2 mm) and a binder are mixed, heated, and pressed.

  The dust core 11 includes a plurality of (for example, three) winding body portions 11c (arrows) provided equally on the yoke portion 11b (range of arrow T) and the outer peripheral surface (radially outer side) 11bo of the yoke portion 11b. U range) and teeth portions 11d (range of arrow V) provided on the outer peripheral surface (radially outer side) 11co of each winding body portion 11c. The rotating shaft 12 is provided at the center portion of the dust core 11 so that the Z axis Z, which is the central axis of the rotating shaft 12, coincides with the axis of the dust core 11. Here, the outer peripheral surface 11co of the winding body portion 11c forms a part of the inner peripheral surface (radially inner side) 11di of the arc-shaped tooth portion 11d.

  In the pressure molding, in the rotary shaft 12 and the yoke portion 11b, each location along the radial direction from the Z axis Z to the outer peripheral surface 11bo of the yoke portion 11b has a first temperature pattern in which the temperature is gradually lowered. The temperature distribution is set to any one of a second temperature pattern in which the temperature is lowered stepwise and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined.

  Further, in the winding body portion 11c and the tooth portion 11d, the outer peripheral surface (radial direction) of the tooth portion 11d from the inner peripheral surface (radially inner side) 11ci (a part of the outer peripheral surface 11bo of the yoke portion 11b) of the winding body portion 11c. Outer) Each location along the radial direction leading to 11do has a first temperature pattern in which the temperature is gradually lowered, a second temperature pattern in which the temperature is gradually lowered, a first temperature pattern, and a second temperature pattern. The temperature distribution is set to any one of the combined third temperature patterns.

  By pressure molding under the above first, second, and third temperature patterns, after molding, along the radial direction from the Z axis Z to the outer peripheral surface 11bo of the yoke portion 11b in the rotary shaft 12 and the yoke portion 11b. Each location is one of a first intensity distribution that gradually decreases, a second intensity distribution that gradually decreases, and a third intensity distribution that combines the first intensity distribution and the second intensity distribution. The mechanical strength indicated by is obtained.

  When the motor rotates, the stress at each location of the yoke part 11b and the rotary shaft 12 caused by the centrifugal force of the rotor 13 increases as it approaches the Z axis Z from the outer peripheral surface 11bo of the yoke part 11b. The mechanical strength increases as the third strength distribution approaches the Z-axis Z. As a result, damage to the rotating shaft 12 and the yoke portion 11b can be suppressed.

  By the pressure molding in the first, second, and third temperature patterns described above, in the winding body 11c and the teeth 11d, the inner surface 11ci of the winding body 11c reaches the outer surface 11do of the teeth 11d. Each location along the radial direction is a first intensity distribution that gradually decreases, a second intensity distribution that gradually decreases, and a third intensity distribution that combines the first intensity distribution and the second intensity distribution. The mechanical strength indicated by the intensity distribution is obtained.

  In addition, after pressure molding, in the winding body part 11c and the tooth part 11d, the stress in each place generated by the centrifugal force of the rotor 13 is caused from the outer peripheral surface 11do of the tooth part 11d to the inner peripheral surface 11ci of the winding body part 11c. It gets higher as you get closer to. However, since the mechanical strength increases as it approaches the inner peripheral surface 11ci due to the above-described first, second, and third strength distributions, damage to the winding body portion 11c and the tooth portion 11d can be suppressed. By the above, since damage to the rotating shaft 12, the yoke part 11b, the winding body part 11c, and the tooth part 11d can be suppressed, damage to the rotor 13 can be prevented.

  Further, each location of the yoke portion 11b along the radial direction from the Z axis Z to the outer peripheral surface 11bo of the yoke portion 11b after molding by the pressure molding under the first, second, and third temperature patterns described above. Is indicated by any one of the first resistance distribution that gradually increases, the second resistance distribution that gradually increases, and the third resistance distribution that combines the first resistance distribution and the second resistance distribution. Electrical resistance is obtained.

  When the motor rotates, the magnetic flux density at each location of the yoke portion 11b generated by the alternating magnetic flux increases as it approaches the outer peripheral surface 11bo of the yoke portion 1b from the Z axis Z of the rotating shaft 12, but the first, second, and second mentioned above. Since the electrical resistance increases as it approaches the outer peripheral surface 11bo from the Z axis Z due to the three resistance distribution, an increase in iron loss in the yoke portion 11b is suppressed.

  Further, by molding under the above-described first, second, and third temperature patterns, the teeth are formed from the inner peripheral surface 11ci of the winding body 11c in the winding body 11c and the teeth 11d after forming. Each location along the radial direction to the outer peripheral surface 11do of 11d is a combination of the first resistance distribution that gradually increases, the second resistance distribution that increases stepwise, the first resistance distribution, and the second resistance distribution. An electrical resistance indicated by any one of the third resistance distributions is obtained.

  When the motor rotates, each location generated by the alternating magnetic flux between the winding body portion 11c and the tooth portion 11d is higher than the magnetic flux density due to the alternating magnetic flux near the center of the yoke portion 11b. However, the electrical resistance of each part of the winding body part 11c and the tooth part 11d is changed from the inner peripheral surface 11ci of the winding body part 11c to the outer peripheral surface 11do of the tooth part 11d by the first, second, and third resistance distributions described above. As it gets closer, it increases and is larger than the electric resistance near the center of the yoke portion 11b. Therefore, the iron loss of the winding body part 11c and the teeth part 11d is suppressed. Furthermore, the iron loss of the winding body part 11c and the tooth part 11d can be reduced by increasing the area of the cross section orthogonal to the magnetic flux flowing through the winding body part 11c and the tooth part 11d.

  As described above, it is possible to provide the rotor 13 with less iron loss while suppressing the increase in iron loss while ensuring the mechanical strength to suppress breakage.

  Moreover, since the dust core 11 and the rotating shaft 12 are integrally molded, the rotor 13 does not require a press-fitting step of the rotating shaft 12 to the dust core 11 and does not require a reinforcing member for preventing breakage. Is reduced and costs are reduced.

  In Example 1 and Example 2, each temperature pattern is set to the dust core 1 or the rotor 13 at the time of pressure molding, and the molding and adhesion of the dust core 1 or the rotor 13 are performed almost simultaneously. . However, after forming the shape of the dust core 1 or the rotor 13, each part of the dust core 1 or the rotor 13 is set to one temperature pattern among the first, second, and third temperature patterns, You may provide the heat processing process which heat-bonds magnetic powder. In this case, by molding, a certain mechanical strength and electrical resistance can be obtained over the whole of the dust core 1 or the rotor 13, but thereafter, a predetermined mechanical strength and a predetermined electrical resistance are ensured by heat bonding. The

  Moreover, in Example 1 and Example 2, although the insulating material is coat | covered on the surface of magnetic body powder and it becomes the structure which adds a binder, it is good also as a structure which utilizes an insulating material as a binder. In this case, the surface of the magnetic powder may be coated with an insulating material made of a binder in advance, or the magnetic material and the binder are molded in a mixed state so that an insulating film is formed on the surface of the magnetic powder. May be.

  Moreover, you may use a thermosetting resin as a binder. In this case, the strength on the radially inner side set to a relatively high temperature can be increased, and the strength distribution of the dust core 1 or the rotor 13 corresponding to the temperature pattern can be controlled more appropriately.

1, 11 Dust core (rotor core)
1a Center hole 1b, 11b Yoke part 1c, 11c Winding trunk part 1d, 11d Teeth part 2, 12 Rotating shaft 13 Rotor Z Z axis (central axis)

Claims (4)

A yoke part in which a central hole capable of press-fitting a rotation shaft is formed in the inner peripheral part;
A plurality of winding body portions protruding from the outer periphery of the yoke portion and capable of winding the winding;
A teeth portion provided on the radially outer side of each of the winding body portions;
An iron core for a rotor with
The rotor iron core is formed by pressure molding magnetic powder and a binder,
The yoke portion has a first temperature pattern in which the temperature gradually decreases in the radial direction from the inner peripheral portion to the outer peripheral portion, and a second temperature in which the temperature is decreased stepwise in the radial direction from the inner peripheral portion to the outer peripheral portion. An iron core for a rotor, wherein the core is heated and bonded with a temperature distribution of any one of a pattern and a third temperature pattern obtained by combining the first temperature pattern and the second temperature pattern. The winding body portion and the teeth portion are stepped in a radial direction from the radially inner side to the radially outer side, a first temperature pattern in which the temperature gradually decreases in the radial direction from the radially inner side to the radially outer side. The heat-bonding is performed at any one of a second temperature pattern in which the temperature is lowered and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. Item 2. The rotor iron core according to Item 1. A rotation provided with a yoke portion, a plurality of winding body portions projecting from the outer peripheral portion of the yoke portion and capable of winding a winding, and a tooth portion provided radially outside each of the winding body portions Child iron core,
A rotating shaft provided at the center of the yoke portion;
A rotor with
The rotor is formed by press molding magnetic powder and a binder,
The rotating shaft and the yoke portion are a first temperature pattern in which the temperature gradually decreases in the radial direction from the central axis of the rotating shaft to the outer peripheral portion of the yoke portion, and from the central axis of the rotating shaft to the yoke portion. Heat bonding with a temperature distribution of any one of a second temperature pattern in which the temperature is lowered stepwise in the radial direction to the outer periphery, and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined Rotor characterized by being made. The winding body portion and the teeth portion are stepped in a radial direction from the radially inner side to the radially outer side, a first temperature pattern in which the temperature gradually decreases in the radial direction from the radially inner side to the radially outer side. The heat-bonding is performed at any one of a second temperature pattern in which the temperature is lowered and a third temperature pattern in which the first temperature pattern and the second temperature pattern are combined. Item 4. The rotor according to item 3.

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