JP6451402B2 - Rotor for rotating electrical machines - Google Patents

Description

  The present invention relates to a rotor for a rotating electrical machine including a rotor core configured by laminating a plurality of electromagnetic steel plates in a rotation axis direction.

  In many cases, a rotor core constituting a rotor of a rotating electrical machine is formed in the form of a laminated core in which a plurality of thin steel plates are laminated in a direction along the rotation axis in order to reduce iron loss. The laminated steel plates are fixed by various methods. One of them is a method of fixing steel plates adjacent to each other in the rotation axis direction by welding. Japanese Unexamined Patent Publication No. 2011-259689 (Patent Document 1) exemplifies a rotor core formed by fixing a steel plate by welding as described above (paragraphs 86 to 88, FIGS. 16 to 18 and the like). This rotor core constitutes a rotor of an inner rotor type rotating electrical machine, and is formed by laminating a plurality of annular steel plates having through holes that fit into a rotating shaft (shaft) in the rotating shaft direction. On the inner peripheral surface of the rotor core that defines the through hole, a curved groove extending in a straight line along the rotation axis direction is formed from one end side to the multi-end side in the rotation axis direction. The curved groove is formed in an arc shape that is recessed radially outward in a cross section orthogonal to the rotation axis. This curved groove serves as a welding target location for welding steel plates adjacent to each other in the rotation axis direction. Since this welding target location is located in a location that is recessed in the radial direction from the surface where the rotating shaft and the through hole contact after welding, the fitting between the rotor core after welding and the rotating shaft is not hindered.

  By the way, in the permanent magnet type rotating electrical machine, a permanent magnet is attached to the rotor core. In many cases, the permanent magnet is continuously arranged along the rotation axis direction and is joined to the rotor core. Permanent magnets include those that expand and contract due to heat with the same tendency as steel plates (those with the same sign of thermal expansion coefficient) and those that expand and contract with different tendencies from steel plates (those with opposite thermal expansion coefficients). . If the thermal expansion characteristics are different between the steel plate and the permanent magnet, a thermal stress (temperature change) may cause a tensile stress in the direction of the rotation axis, and the rotor core may exhibit a deformation behavior. In general, since a steel plate has a positive expansion coefficient, when the permanent magnet has a negative expansion coefficient in the direction of the rotation axis of the rotor, there is a possibility that a stress in a direction of peeling off the welded portion may be applied. As a result of applying stress in the direction in which the welding is peeled off, if the welded portion is cracked or the like, the mechanical strength may decrease, which is not preferable.

JP 2011-259689 A

  In view of the above-mentioned background, in a rotor for a rotating electrical machine in which a permanent magnet is joined to a rotor core in which laminated steel plates are fixed by welding, provision of technology for ensuring high reliability by reducing stress on the welded part due to thermal shock Is desired.

In view of the above, a rotor for a rotating electrical machine including a rotor core configured by laminating a plurality of electromagnetic steel plates in the rotation axis direction is one aspect,
A permanent magnet whose thermal expansion coefficient in the direction of the rotation axis is opposite to that of the magnetic steel sheet;
A rotating member that supports the rotor core,
The rotating member is a first circumferential surface of the rotor core on the first radial direction side, with one radial side of the rotor core being the first radial direction side and the other radial side being the second radial direction side. Supporting the circumferential surface in the radial direction,
The rotor core is supported so that both end portions of the rotor core in the rotation axis direction do not move relative to the rotation member in the rotation axis direction,
A plurality of the permanent magnets are arranged in a distributed manner in the circumferential direction of the rotor core on the second radial direction side than the radial intermediate position in the radial thickness of the rotor core,
Each of the permanent magnets is disposed along the rotation axis direction and joined to the rotor core,
The rotor core has a weld portion on the first circumferential surface for welding a plurality of the electromagnetic steel sheets to each other,
The welded portion is recessed toward the second radial direction side with respect to a reference circumferential surface that is a circumferential surface of a general portion other than the welded portion on the first circumferential surface and continuously extends along the rotational axis direction. A first groove portion, a second groove portion that is recessed in the second radial direction side with respect to the reference circumferential surface and extends in parallel with the first groove portion, the first groove portion, and the first groove portion. A projecting portion sandwiched between two circumferential groove portions and projecting toward the first radial direction side and continuously extending along the rotational axis direction,
It is preferable that the projecting portion is formed such that a top portion of the projecting portion on the first radial direction side is located on the second radial direction side with respect to the reference circumferential surface.

  For example, in Patent Document 1, the curved groove corresponding to the welded portion is relatively large and recessed toward the second radial direction from the reference circumferential surface. However, in this structure, the top part of the projection part of a welding part is located in the radial first direction side compared with such a curved groove. That is, if the radial thickness of the rotor core is the same, in this configuration, the distance between the welding target portion and the permanent magnet is the same as the distance between the top of the protruding portion protruding in the first radial direction side. Longer than 1. The welded part is the part where the magnetic steel sheet is melted and solidified (melted and solidified part). The longer the distance between the melted and solidified part and the permanent magnet, the less the stress applied to the melted and solidified part when a thermal shock occurs. The When the thermal expansion coefficient between the electrical steel sheet and the permanent magnet is opposite, a tensile stress is applied to the melted and solidified part due to thermal shock, but if the distance between the melted and solidified part and the permanent magnet is long, the tensile stress is reduced. . That is, according to this configuration, in a rotor for a rotating electrical machine in which a permanent magnet is joined to a rotor core in which laminated steel plates are fixed by welding, stress on the welded part due to thermal shock is reduced and high reliability is ensured. Is possible.

  Moreover, according to this structure, since the 1st ditch | groove part and the 2nd ditch | groove part are provided in the both sides of the circumferential direction of the protrusion part used as welding object, it is easy to deform | transform a welded part. Therefore, distortion caused by welding hardly affects other than the welded portion, and distortion generated in the rotor core accompanying welding is also reduced. By reducing the distortion, the roundness of the rotor core is improved. It should be noted that the radial depth and the circumferential width of the first groove portion and the second groove portion are within a range in which the magnetic path passing through the rotor core is not disturbed and the magnetic characteristics are not obstructed, so that the distortion reduction effect becomes more effective as it is set. Get higher. Further, the width of the projecting portion in the circumferential direction is set within a range that does not interfere with the magnetic characteristics, and the welding width increases as the setting is increased, and the welding depth can be reduced.

  Further features and advantages of the present invention will become apparent from the following description of embodiments of the invention which will be described with reference to the drawings.

Cross-sectional view of the rotor in the rotation axis Cross-sectional view of the rotor core in the rotation axis direction Plan view of the rotor viewed in the direction of the rotation axis Enlarged view of the vicinity of the welded part of the rotor core Enlarged view of the vicinity of the welded portion of the rotor core of the comparative example Partial sectional view in the direction of the rotation axis of the stress simulation model of the rotor Partial sectional view in the direction of the rotation axis of the stress simulation model at high temperature Partial sectional view in the direction of the rotation axis of the stress simulation model at low temperatures Explanatory drawing schematically showing the gap and opening angle due to tensile stress Explanatory drawing which shows typically the space | gap and its opening angle in the rotor of a comparative example Enlarged view of the vicinity of the first melt-solidified part of the rotor core The enlarged view which shows the other example of arrangement | positioning of the permanent magnet and welding part in a rotor core

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a rotor 1 (rotor for a rotating electrical machine) provided in an inner rotor type rotating electrical machine will be described as an example. FIG. 1 is a cross-sectional view of the rotor 1 in the rotation axis direction L. FIG. The rotor 1 includes a rotor core 2, a permanent magnet 4, and a hub 5 (rotating member) that connects the rotor core 2 to a shaft (not shown) as the rotation axis X. FIG. 2 is a cross-sectional view in the rotational axis direction L of the rotor core 2 in a state where the hub 5 is not attached to the rotor core 2. Although details will be described later, the rotor core 2 is formed by laminating a plurality of annular electromagnetic steel plates 3, and the electromagnetic steel plates 3 are joined to each other by welding before the hub 5 is attached to the rotor core 2. The symbol “W1” in FIG. 2 schematically shows a melt-solidified portion that has been melted and solidified by welding. FIG. 3 is a plan view seen from the direction along the rotation axis direction L of the rotor core 2.

  In this embodiment, after the electromagnetic steel plates 3 forming the rotor core 2 are joined to each other by welding, the hub 5 is attached to the rotor core 2 and the hub 5 and the rotor core 2 are joined by welding. The symbol “W2” in FIG. 1 also schematically shows a melt-solidified portion that has been melted and solidified by welding. As described above, first, the steel plates of the rotor core 2 are welded together, and then the rotor core 2 and the hub 5 are welded. Therefore, when distinguishing the melt-solidified portion shown in FIG. 2 from the melt-solidified portion shown in FIG. 1, the melt-solidified portion shown in FIG. 2 is designated as the first melt-solidified portion W1, and the melt-solidified portion shown in FIG. This is referred to as a two-melt solidified portion W2. FIG. 2 shows a cross section passing through the welded portion 10 described later, that is, a cross section passing through the first melt-solidified portion W1. FIG. 1 shows a cross section that does not pass through the welded portion 10 after the hub 5 is attached to the rotor core 2, that is, a cross section that does not pass through the first melt-solidified portion W1. The rotor 1 (or rotor core 2) of this embodiment is characterized by the structure of the welded portion 10. FIG. 4 is an enlarged view of the vicinity of the welded portion 10.

  Hereinafter, the rotor 1 according to the present embodiment will be described in detail. In the following description, unless otherwise specified, the “rotational axis direction L”, “radial direction R”, and “circumferential direction C” are based on the axis of the rotor core 2 (that is, the rotational axis X). Also, one side of the radial direction R of the rotor core 2 is defined as the first radial direction R1 side, and the other side of the radial direction R is defined as the second radial direction R2 side. As shown in FIG. 1, in this embodiment illustrating the rotor 1 of the inner rotor type rotating electrical machine, the “diameter first direction R1” represents a direction toward the inner side (axial center side) of the radial direction R, and “ The second radial direction R2 "represents a direction toward the outer side (not shown) of the radial direction R. That is, the “diameter first direction R1 side” is “radially inner” and the “diameter second direction R2 side” is “radially outer”. Further, the dimensions, arrangement direction, arrangement position, and the like of each member include a state having a difference due to an error (an error that is acceptable in manufacturing).

  As shown in FIG. 1, the rotor 1 includes a rotor core 2, permanent magnets 4, and a hub 5 (rotating member). In many cases, a rotor core constituting a rotor of a rotating electrical machine is formed in the form of a laminated core in which a plurality of thin steel plates are laminated in a direction along the rotation axis in order to reduce iron loss. Also in this embodiment, as shown in FIGS. 1 and 2, the rotor core 2 is configured by laminating a plurality of electromagnetic steel plates 3 in the rotation axis direction L. The rotor core 2 is fixed to a shaft (not shown) as the rotation axis X via the hub 5. As shown in FIG. 1, the hub 5 is a member that supports a first circumferential surface CP1 that is a circumferential surface of the rotor core 2 on the radial first direction R1 side in the radial direction R. The rotor core 2 is supported so that both ends of the rotor core 2 in the rotation axis direction L do not move relative to the hub 5 in the rotation axis direction L. In the present embodiment, as described above, the hub 5 and the rotor core 2 are joined by welding, and the rotor core 2 is supported so as not to move relative to the hub 5. The hub 5 and a shaft (not shown) are connected by shrink fitting, key connection, spline connection, or the like.

  The permanent magnet 4 is made of a magnetic material disposed on the rotor core 2 such that the radial direction R is a magnetization direction and the rotation axis direction L is a non-magnetization direction. The thermal expansion coefficient of the magnetic material in the non-magnetization direction is opposite to that of the electromagnetic steel sheet 3. In this embodiment, this magnetic material has neodymium as the core. The permanent magnet 4 is a neodymium magnet, and its coefficient of thermal expansion in the non-magnetization direction is a negative value. On the other hand, the thermal expansion coefficient of the electromagnetic steel sheet 3 is a positive value regardless of the direction. Therefore, the permanent magnet 4 is a magnet whose thermal expansion coefficient in the non-magnetization direction is opposite to that of the electromagnetic steel sheet 3.

  As shown in FIG. 3, a plurality of permanent magnets 4 are arranged in the circumferential direction C of the rotor core 2 on the radial second direction R2 side from the radial intermediate position R3 in the radial thickness RW of the rotor core 2. Yes. The rotor core 2 is formed with a magnet insertion hole penetrating in the rotation axis direction L, and a permanent magnet 4 having substantially the same rotation axis direction length as the rotor core 2 is inserted into the magnet insertion hole and fixed to the rotor core 2. ing. That is, each of the permanent magnets 4 is continuously disposed along the rotation axis direction L and is joined to the rotor core 2. The permanent magnet 4 may be joined to the surface of the rotor core 2. That is, the rotor 1 is not limited to an embedded magnet type rotor, but may be a surface magnet type rotor.

  As described above, the rotor core 2 is configured by laminating a plurality of annular electromagnetic steel plates 3 in the rotation axis direction L. Moreover, in this embodiment, the fixing member called what is called an end plate is not provided in the both ends of the rotor core 2 in the rotating shaft direction L. Further, in order to fix the plurality of electromagnetic steel plates 3, the adjacent steel plates in the rotation axis direction L are joined together by welding. For this reason, the welding part 10 used as the welding object location is formed in the rotor core 2. As shown in FIG. In this embodiment, as shown in FIGS. 3 and 4, a welded portion 10 for welding a plurality of electromagnetic steel sheets 3 to each other is formed on the first circumferential surface CP <b> 1 of the rotor core 2.

  By irradiating the welded part 10 with an energy beam B such as an electron beam or a laser beam, the electromagnetic steel sheet 3 is melted and then solidified, so that the adjacent electromagnetic steel sheets 3 in the rotation axis direction L are welded. As shown in FIG. 2, by irradiating the welded portion 10 with the energy beam B along the rotation axis direction L, a plurality of electromagnetic steel plates 3 are joined as one rotor core 2. The first molten and solidified portion W1 indicates a portion where a plurality of electromagnetic steel plates 3 are melted and solidified by the energy beam B irradiated along the rotation axis direction L. As will be described later, for example, the energy beam B may not be applied to the electromagnetic steel sheet 3 in the vicinity of both ends in the rotation axis direction L. Therefore, the first melt-solidified portion W1 does not need to be formed over the entire region in the rotation axis direction L.

  Although details will be described later, all the portions of the welded portion 10 are formed on the second radial direction R2 side with respect to the reference circumferential surface CR that is the circumferential surface of the general portion 20 other than the welded portion 10 in the first circumferential surface CP1. ing. In other words, the reference circumferential surface CR is an inner wall or an outer wall of a virtual cylinder whose cross section around the rotation axis X is a perfect circle, and is an ideal circumferential surface. The general portion 20 is formed so as to coincide with an ideal peripheral surface that is an inner wall or an outer wall of the virtual cylinder. The surface of the hub 5 that contacts the rotor core 2 is also formed so as to coincide with this ideal peripheral surface. Since all the parts of the welded portion 10 are formed on the second radial direction R2 side with respect to the reference circumferential surface CR, the first melt-solidified portion W1 also has a second radial direction R2 with respect to the reference circumferential surface CR. Formed on the side. The hub 5 is disposed so as to abut on the reference circumferential surface CR. At this time, the first melt-solidified portion W1 does not prevent the abutment between the hub 5 and the rotor core 2.

  The hub 5 contacts the general part 20 and is fixed to the rotor core 2. As shown in FIGS. 1 and 3, at both end portions in the rotation axis direction L, the energy beam B is applied to the circumferential portion where the hub 5 and the general portion 20 abut, and the hub 5 and the rotor core 2 are connected. Welded. A second melt-solidified portion W2 is formed at a portion where the hub 5 and the general portion 20 abut. Thus, the second molten and solidified portion W2 is formed on the electromagnetic steel sheet 3 in the vicinity of both end portions in the rotation axis direction L. The second molten and solidified portion W2 is formed across a plurality of electromagnetic steel sheets 3. Therefore, the electromagnetic steel sheet 3 in the vicinity of both ends in the rotation axis direction L may not be welded by the energy beam B irradiated along the rotation axis direction L.

  When the energy beam B is irradiated from one end portion of the rotor core 2 to the other end portion along the rotation axis direction L, the electromagnetic steel sheet 3 is reduced at both end portions, so that the energy becomes excessive. As a result, if the molten electromagnetic steel sheet 3 exceeds the boiling point, there is a possibility that a void is formed inside the rotor core 2 after solidification. Such a gap leads to a decrease in the magnetic performance of the rotor core 2. During welding, if it is attempted to control the irradiation force of the energy beam B according to the irradiation target position, the welding process may become complicated. However, if the steel plates existing at both ends in the rotational axis direction L are joined by the second melt-solidified portion W2, such control of the energy beam B is not necessary.

  Hereinafter, the structure of the welding part 10 is demonstrated. As shown in FIG. 4, the welded portion 10 includes a first concave groove portion 11, a second concave groove portion 12, and a protruding portion 13. The first groove portion 11 is formed so as to be recessed in the second radial direction R2 side with respect to the reference circumferential surface CR and continuously extend along the rotation axis direction L. The second concave groove portion 12 is formed so as to be recessed in the radial second direction R2 side with respect to the reference circumferential surface CR and to extend continuously in parallel with the first concave groove portion 11. The projecting portion 13 is sandwiched between the first concave groove portion 11 and the second concave groove portion 12 in the circumferential direction C, protrudes toward the first radial direction R1, and continuously extends along the rotation axis direction L. Is formed. In other words, the first groove portion 11 and the second groove portion 12, which are a pair of groove portions, are retracted in the radial second direction R 2 side on both sides in the circumferential direction C of the protruding portion 13, respectively, in the rotation axis direction L. It is formed so as to extend continuously along.

  The protruding portion 13 is formed such that the apex portion 14 that is the end portion on the radial first direction R1 side in the protruding portion 13 is positioned on the radial second direction R2 side with respect to the reference circumferential surface CR. Of all the parts of the welded part 10, the part located closest to the first radial direction R <b> 1 is the top 14. Therefore, all the parts of the welded portion 10 are formed on the radial second direction R2 side with respect to the reference circumferential surface CR. The energy beam B is irradiated with the top portion 14 as a target. Accordingly, the first melt-solidified portion W1 is formed around the top portion 14. As described above, on both sides in the circumferential direction C of the top portion 14, that is, on both sides in the circumferential direction C of the protruding portion 13, grooves (first concave groove portion 11 and second concave groove portion 12) recessed toward the radial second direction R <b> 2. ) Is formed. Therefore, even if the molten electromagnetic steel sheet 3 flows in the direction of these grooves, the possibility that the molten steel sheet 3 protrudes toward the first radial direction R1 side from the initial position of the top portion 14 is extremely low. Accordingly, the first molten and solidified portion W1 is formed so as not to prevent the connection between the rotor core 2 and the hub 5 without growing in the first radial direction R1 side from the reference circumferential surface CR.

  By the way, in this embodiment, as shown in FIG. 4, the shape of the welding part 10 in the cross section orthogonal to the rotating shaft X of 1st surrounding surface CP1 is the 1st groove part 11, the protrusion part 13, and the 2nd recessed part. It is a curvilinear shape that continuously connects the groove 12. By providing the first groove portion 11 and the second groove portion 12 on both sides in the circumferential direction C of the protruding protrusion 13, the welded portion 10 is easily deformed. Therefore, distortion caused by welding hardly affects other than the welded portion 10, and distortion generated in the rotor core 2 due to welding is reduced.

  For example, FIG. 5 is an enlarged view near the welded portion 10B of the rotor core 2 of the comparative example. The welded portion 10B of this comparative example is constituted by one concave groove portion. According to experiments and simulations by the inventors, when welding is performed by irradiating the welded portion 10B of the comparative example with the energy beam B, distortion generated in the rotor core 2 compared to the case where the welded portion 10 of the present embodiment is welded. Becomes larger. The distortion of the rotor core 2 includes changes in dimensions of the inner diameter φ1 and the outer diameter φ2 shown in FIG. As a result of experiments and simulations, it has been confirmed that in the rotor core 2 of the present embodiment, such a change in dimensions is reduced compared to the rotor core 2 of the comparative example.

  Moreover, the stress applied to the first melt-solidified portion W1, specifically, the tensile stress in the laminating direction (rotational axis direction L) of the electromagnetic steel sheet 3 is also suppressed by the shape of the welded portion 10 of the present embodiment. Hereinafter, the effect of reducing the stress will be described with reference to FIGS. 6 to 8 schematically show a VI-VI cross section in FIG. FIG. 6 is a partial cross-sectional view in the rotation axis direction L of the stress simulation model of the rotor 1 at room temperature. FIG. 7 is a partial cross-sectional view in the rotational axis direction L of the stress simulation model considering the deformation of the rotor 1 at a high temperature. FIG. 8 is a partial cross-sectional view in the rotational axis direction L of the stress simulation model considering the deformation of the rotor 1 at a low temperature. In this simulation model, the thickness of the electromagnetic steel sheet 3 is 10 to 20 times the actual thickness. Further, the deformation amount is exaggerated to about 100 times the actual amount and is schematically illustrated.

  FIG. 6 is a partial cross-sectional view at about normal temperature (for example, about 20 to 25 [° C.]). At this environmental temperature, neither the magnetic steel sheet 3 nor the permanent magnet 4 is thermally expanded or contracted. FIG. 7 is a partial cross-sectional view at a high temperature (for example, about 150 to 200 [° C.]). At this environmental temperature, the electrical steel sheet 3 having a positive thermal expansion coefficient expands, and the permanent magnet 4 having a negative thermal expansion coefficient contracts. Tensile stress in the direction of peeling the electromagnetic steel sheet 3 adjacent to the rotation axis direction L may be generated on the first radial direction R1 side, that is, the first circumferential surface CP1, but both end portions of the rotor core 2 in the rotation axis direction L are The second melted and solidified portion W2 is fixed to the hub 5. For this reason, stress is unlikely to occur on the first peripheral surface CP1.

  FIG. 8 is a partial cross-sectional view at a low temperature (for example, about −30 to −40 [° C.]). At this environmental temperature, the electrical steel sheet 3 having a positive thermal expansion coefficient contracts, and the permanent magnet 4 having a negative thermal expansion coefficient expands. A tensile stress in the direction of peeling off the electromagnetic steel sheet 3 adjacent to the rotation axis direction L is generated on the second radial direction R2 side of the permanent magnet 4, that is, on the second circumferential surface CP2. In addition, the permanent magnet 4 that expands in the rotation axis direction L on the first radial direction R1 side from the permanent magnet 4, that is, the first circumferential surface CP1, tries to peel the electromagnetic steel sheet 3 from the second radial direction R2 side. . That is, unlike the case of high temperature, tensile stress along the rotational axis direction L is applied to the electromagnetic steel sheet 3 from the side not fixed by the hub 5. FIG. 8 schematically shows a gap V generated between the electromagnetic steel sheets 3 adjacent to each other in the rotation axis direction L due to such tensile stress.

  FIG. 9 is an explanatory diagram schematically showing the gap V (V1) due to the tensile stress and the opening angle θ1 thereof in the rotor 1 of the present embodiment. FIG. 10 is an explanatory diagram schematically showing the gap V (V2) due to the tensile stress and the opening angle θ2 in the rotor 1 of the comparative example. FIG. 11 is an enlarged view of the vicinity of the first melt-solidified portion W1 of the rotor core 2. As is clear from a comparison between FIG. 5 and FIG. 11, the welded portion 10 of the present embodiment has the protruding portion 13, whereby the distance in the radial direction R between the permanent magnet 4 and the first melt-solidified portion W <b> 1. CL (CL1) is longer than the distance CL (CL2) in the radial direction R between the permanent magnet 4 of the comparative example and the first molten and solidified portion W1. As a result, the tensile stress applied to the first melt-solidified portion W1 of the present embodiment is smaller than the tensile stress applied to the first melt-solidified portion W1 of the comparative example.

  9 and 10 are schematic diagrams for considering from the shape of the gap V that the tensile stress applied to the first melt-solidified portion W1 of the present embodiment becomes smaller. The difference in the length of the distance CL between the permanent magnet 4 and the first melt-solidified portion W1 is also the difference in the length in the radial direction R of the void V caused by the tensile stress, as shown in FIGS. That is, the force acting in the direction of widening the gap V has a correlation with the size of the opening angle (θ1, θ2) of the gap V shown in FIGS. Specifically, as the opening angle (θ1, θ2) increases (closer to 90 degrees), the force along the rotation axis direction L, that is, the tensile stress increases. As shown in the figure, the opening angle θ1 of the gap V1 in this embodiment is smaller than the opening angle θ2 of the gap V2 in the comparative example. Therefore, the tensile stress is smaller in the present embodiment than in the comparative example. According to experiments and simulations by the inventors, it was confirmed that the tensile stress was reduced by about 53% in this embodiment compared to the comparative example.

  For example, the curved groove of Patent Document 1 corresponding to the welded portion 10 </ b> B in the comparative example is relatively large and recessed toward the second radial direction R <b> 2 from the reference circumferential surface CR, and the radial direction between the welded portion and the permanent magnet 4. The distance at R is closer. However, in the present embodiment, the top portion 14 of the protruding portion 13 of the welded portion 10 is located on the radial first direction R1 side as compared with such a curved groove. In other words, if the radial thickness RW of the rotor core 2 is the same, the distance between the permanent magnet 4 and the welded portion (the top portion 14) is longer in the structure of the present embodiment than in the structure of Patent Document 1. Become. The welded portion is a portion where the electromagnetic steel sheet 3 is melted and solidified (first melt-solidified portion W1). The longer the distance CL between the first melt-solidified portion W1 and the permanent magnet 4, the more the first time when a thermal shock occurs. The tensile stress applied to one melt-solidified part W1 is reduced. That is, according to the configuration of the present embodiment, it is possible to obtain the rotor 1 capable of reducing the stress on the welded part due to the thermal shock and ensuring high reliability.

  Moreover, according to this embodiment, since the 1st groove part 11 and the 2nd groove part 12 are provided in the both sides of the circumferential direction C of the protrusion part 13 welded, the distortion which arises in the rotor core 2 with welding is also produced. As described above, the roundness of the rotor core 2 is improved. It should be noted that the depth in the radial direction R and the width in the circumferential direction C of the first concave groove portion 11 and the second concave groove portion 12 are set so large that the magnetic path passing through the rotor core 2 is prevented and the magnetic characteristics are not disturbed. The effect of reducing distortion increases. Further, the width of the protruding portion 13 in the circumferential direction C can be increased as the width is set so as not to interfere with the magnetic characteristics, and the welding depth can be reduced.

[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of other embodiments as long as no contradiction arises.

(1) In the above, as shown in FIG. 3, an example in which a plurality of permanent magnets 4 are arranged in the circumferential direction C near the second radial direction R <b> 2 is illustrated. That is, the single permanent magnet 4 forms one magnetic pole, and the welded portion 10 is formed at a position overlapping the circumferential central portion in the circumferential width CW of the single permanent magnet 4 (magnetic pole M). An example is shown. However, the permanent magnet 4 may be arranged so that one magnetic pole M is formed by the plurality of permanent magnets 4. For example, as illustrated in FIG. 12, the permanent magnet 4 may be arranged such that one magnetic pole M is formed by arranging two permanent magnets 4 in a V shape. In this case, the welded portion 10 is formed at a position overlapping between the two permanent magnets 4 forming one magnetic pole M. That is, regardless of the number of permanent magnets 4 constituting one magnetic pole M, the welded portion 10 is formed at a position overlapping with the circumferential central portion in the circumferential width CW of one magnetic pole M when viewed in the radial direction R. It only has to be done. In addition, in FIG. 12, although the shape where the two permanent magnets 4 are arranged in a V shape such that the distance between each other becomes wider in the second radial direction R2 is illustrated, the arrangement of the plurality of permanent magnets 4 is illustrated. The form is not limited to this form.

(2) In the above, the case where the rotor 1 is a rotor used for an inner rotor type rotating electrical machine is illustrated, but the rotor 1 may naturally be a rotor used for an outer rotor type rotating electrical machine. In the above description of the inner rotor type, the radial first direction R1 side is the radial inner side, and the radial second direction R2 side is the radial outer side. In the outer rotor type rotating electrical machine, the first radial direction R1 side is the radially outer side, and the second radial direction R2 side is the radially inner side.

(3) In the above, the case where the permanent magnet 4 was a neodymium magnet was illustrated. However, the permanent magnet 4 may not be a neodymium magnet as long as the thermal expansion coefficient in the non-magnetization direction is a material having a sign opposite to that of the electromagnetic steel sheet 3.

(4) In the above, the shape of the welded portion 10 in the cross section orthogonal to the rotation axis X of the first peripheral surface CP1 continuously connects the first concave groove portion 11, the protruding portion 13, and the second concave groove portion 12. The form which is curvilinear was illustrated. However, the shape of the welded portion 10 is not limited to this form, and may be a non-curved shape having corners.

(5) In the above, for example, as illustrated in FIG. 3, the form in which the welded portion 10 is provided only for a part of the permanent magnets 4 is illustrated. That is, 16 permanent magnets 4 are arranged in the circumferential direction C, whereas the welded portions 10 are formed at eight locations. However, the present invention is not limited to such a form, and one welded portion 10 may be disposed for each permanent magnet 4. Needless to say, welds may be arranged at four locations for 16 permanent magnets 4. This relationship is the same for the relationship between the magnetic pole M and the welded portion 10. In the form illustrated in FIG. 12, the form in which the welded portions 10 are arranged one by one corresponding to each magnetic pole M is illustrated. However, the number of welds 10 may be less than the number of magnetic poles M.

(6) In the above, a structure in which fixing members such as so-called end plates are not provided at both ends of the rotor core 2 in the rotation axis direction L is illustrated. That is, in the above, the form in which the rotor core 2 and the hub 5 are fixed by welding is illustrated. However, a configuration in which the rotor core 2 is fixed relative to a rotating member such as the hub 5 by caulking or bolts using a fixing member such as an end plate may be used. In this embodiment, the rotor core 2 is supported so as not to move relative to the hub 5 using a fixing member such as an end plate.

[Outline of Embodiment of the Present Invention]
Hereinafter, the outline | summary of the rotor (1) for rotary electric machines in embodiment of this invention demonstrated above is demonstrated easily.

A rotor for a rotating electrical machine (1) provided with a rotor core (2) configured by laminating a plurality of electromagnetic steel plates (3) in the direction of the rotation axis (L), as one aspect,
A permanent magnet (4) having a thermal expansion coefficient in the rotational axis direction (L) opposite to that of the electromagnetic steel sheet (3);
A rotating member (5) for supporting the rotor core (2),
The rotating member (5) has one side of the radial direction (R) of the rotor core (2) as the first radial direction (R1) side and the other side of the radial direction (R) as the second radial direction (R2) side. Supports the first circumferential surface (CP1) that is the circumferential surface on the first radial direction (R1) side of the rotor core (2) in the radial direction (R),
The rotor core (2) is supported so that both ends of the rotation axis direction (L) of the rotor core (2) do not move relative to the rotation member (5) in the rotation axis direction (L),
The permanent magnet (4) is arranged in the circumferential direction of the rotor core (2) on the radial second direction (R2) side of the radial intermediate position (R3) in the radial thickness (RW) of the rotor core (2) ( C) are arranged in a distributed manner,
Each of the permanent magnets (4) is disposed along the rotational axis direction (L) and joined to the rotor core (2),
The rotor core (2) has, on the first peripheral surface (CP1), a weld portion (10) for welding a plurality of the electromagnetic steel sheets (3) to each other.
The welded portion (10) has a second radial direction with respect to a reference circumferential surface (CR) that is a circumferential surface of a general portion (20) other than the welded portion (10) in the first circumferential surface (CP1) ( A first concave groove (11) which is recessed toward the R2) side and continuously extends along the rotational axis direction (L), and on the second radial direction (R2) side with respect to the reference circumferential surface (CR). The circumferential direction of the second groove portion (12) that is recessed and extends continuously in parallel with the first groove portion (11), and the first groove portion (11) and the second groove portion (12). A projecting portion (13) sandwiched between (C) and projecting toward the first radial direction (R1) side and continuously extending along the rotational axis direction (L),
The protrusions (13) are arranged so that the top (14) on the first radial direction (R1) side is positioned closer to the second radial direction (R2) side than the reference circumferential surface (CR). It is preferable that the shape portion (13) is formed.

  For example, in Patent Document 1, the curved groove corresponding to the welded portion (10) is relatively large from the reference circumferential surface (CR) to the radial second direction (R2) side. However, in this structure, the top part (14) of the projection part (13) of the welding part (10) is located on the radial first direction (R1) side as compared with such a curved groove. That is, if the radial thickness (RW) of the rotor core (2) is the same, in this configuration, the top portion (14) of the protruding portion (13) protrudes toward the radial first direction (R1). However, the distance (CL) between the welding target portion and the permanent magnet (4) is longer than that in Patent Document 1. The welding target portion is a portion (melted and solidified portion (W1)) in which the electromagnetic steel sheet (3) is melted and solidified. The longer the distance between the melted and solidified portion (W1) and the permanent magnet (4), The stress applied to the melted and solidified portion (W1) when an impact is generated is reduced. When the thermal expansion coefficients of the electrical steel sheet (3) and the permanent magnet (4) have opposite signs, a tensile stress is applied to the melt-solidified part (W1) by thermal shock, but the melt-solidified part (W1) and the permanent magnet ( If the distance to 4) is long, the tensile stress is reduced. That is, according to this configuration, in the rotor for a rotating electrical machine (1) in which the permanent magnet (4) is joined to the rotor core (2) in which the laminated steel plates (3) are fixed by welding, It is possible to reduce stress and ensure high reliability.

  Moreover, according to this structure, since a 1st groove part (11) and a 2nd groove part (12) are provided in the both sides of the circumferential direction (C) of the protrusion part (13) used as welding object, it is a welding part. (10) is easily deformed. Therefore, distortion accompanying welding hardly affects other than the welded portion (10), and distortion generated in the rotor core (2) accompanying welding is also reduced. By reducing the distortion, the roundness of the rotor core (2) is improved. In addition, the depth in the radial direction (R) and the width in the circumferential direction (C) of the first concave groove portion (11) and the second concave groove portion (12) interfere with the magnetic path passing through the rotor core (2) and have a magnetic characteristic. As long as the setting is large, the effect of reducing distortion increases. In addition, the width of the protrusion (13) in the circumferential direction (C) is set within a range that does not hinder the magnetic characteristics, and the welding width increases as the setting is increased, and the welding depth can be reduced.

  Here, the shape of the welded part (10) in the cross section orthogonal to the rotation axis (X) of the first peripheral surface (CP1) is the first concave groove part (11), the protruding part (13), and the It is preferable that the shape is a curve that continuously connects the second concave groove (12). As described above, since the first groove portion (11) and the second groove portion (12) are provided on both sides in the circumferential direction (C) of the protruding portion (13) to be welded, the weld portion (10) is provided. It is easy to deform. Therefore, distortion accompanying welding hardly affects other than the welded portion (10), and distortion generated in the rotor core (2) accompanying welding is reduced. Furthermore, the welded portion (10) is smoothly formed by forming the shape of the welded portion (10) in a curved shape that continuously connects the three portions. With this shape, stress acting on the welded portion (10) can be dispersed, so that the rotor core (2) can have appropriate magnetic characteristics.

  As described above, the welded portion (10) includes the first groove portion (11) and the second groove portion (12) on both sides in the circumferential direction (C), in addition to the protruding portion (13) that is a place to be welded. ) And are provided. And it is preferable that a 1st groove part (11) and a 2nd groove part (12) are provided without preventing the magnetic path in a rotor core (2). That is, as one aspect, when the permanent magnet (4) forms one magnetic pole (M) by a single magnet or a plurality of magnets, the welded portion (10) has a radial direction (R). In view of this, it is preferable that the magnetic pole (M) is formed at a position overlapping with the circumferential central portion in the circumferential width (CW). Here, overlapping means a state in which at least a part of the welded portion (10) overlaps.

  There is a neodymium magnet as the permanent magnet (4) whose thermal expansion coefficient in the rotation axis direction (L), that is, the non-magnetization direction is opposite to that of the electromagnetic steel sheet (3). Therefore, as one aspect, the permanent magnet (4) is preferably a neodymium magnet. It is possible to provide a permanent magnet type rotor for a rotating electrical machine having a strong magnetic force while reducing stress on a welded part due to thermal shock and ensuring high reliability.

  The rotor for a rotating electrical machine (1) is preferably used as a rotor for an inner rotor type rotating electrical machine, which is a type of many consumer rotating electrical machines. It is possible to obtain a highly reliable rotating electrical machine including a permanent magnet type rotor having a strong magnetic force while reducing stress on a welded part due to thermal shock and ensuring high reliability. When the rotor for a rotating electrical machine (1) is provided in an inner rotor type rotating electrical machine, the first radial direction (R1) side is a radially inner side, and the second radial direction (R2) side is a radially outer side. is there.

  INDUSTRIAL APPLICABILITY The present invention can be used for a rotor for a rotating electrical machine including a rotor core configured by laminating a plurality of electromagnetic steel plates in the rotation axis direction.

1: Rotor (rotor for rotating electrical machine)
2: Rotor core 3: Electrical steel sheet 4: Permanent magnet 5: Hub (rotating member)
DESCRIPTION OF SYMBOLS 10: Welding part 11: 1st recessed groove part 12: 2nd recessed groove part 13: Protruding part 14: Top part 20: General part C: Circumferential direction CP1: First circumferential surface CR: Reference circumferential surface CW: Circumferential width of magnetic pole L: Rotational axis direction M: Magnetic pole R: Radial direction R1: Radial first direction R2: Radial second direction R3: Radial intermediate position RW: Radial thickness

Claims (9)

A rotor for a rotating electrical machine including a rotor core configured by laminating a plurality of electromagnetic steel sheets in the rotation axis direction,
A permanent magnet whose thermal expansion coefficient in the direction of the rotation axis is opposite to that of the magnetic steel sheet;
A rotating member that supports the rotor core,
The rotating member is a first circumferential surface of the rotor core on the first radial direction side, with one radial side of the rotor core being the first radial direction side and the other radial side being the second radial direction side. Supporting the circumferential surface in the radial direction,
Both ends of the rotation axis direction of the rotor core and the rotating member are joined by welding ,
A plurality of the permanent magnets are arranged in a distributed manner in the circumferential direction of the rotor core on the second radial direction side than the radial intermediate position in the radial thickness of the rotor core,
Each of the permanent magnets is disposed along the rotation axis direction and joined to the rotor core,
The rotor core has a weld portion on the first circumferential surface for welding a plurality of the electromagnetic steel sheets to each other,
The welded portion is recessed toward the second radial direction side with respect to a reference circumferential surface that is a circumferential surface of a general portion other than the welded portion on the first circumferential surface and continuously extends along the rotational axis direction. A first groove portion, a second groove portion that is recessed in the second radial direction side with respect to the reference circumferential surface and extends in parallel with the first groove portion, the first groove portion, and the first groove portion. A projecting portion sandwiched between two circumferential groove portions and projecting toward the first radial direction side and continuously extending along the rotational axis direction,
The rotor for rotating electrical machines in which the projecting portion is formed such that a top portion of the projecting portion on the first radial direction side is located on the second diameter direction side with respect to the reference circumferential surface. 2. The rotor for a rotating electrical machine according to claim 1, wherein circumferential portions where the rotor core and the rotating member abut are joined by welding at both ends of the rotor core in the rotation axis direction. Each of the said permanent magnet is a rotor for rotary electric machines of Claim 1 or 2 arrange | positioned continuously along the said rotating shaft direction. A rotor for a rotating electrical machine including a rotor core configured by laminating a plurality of electromagnetic steel sheets in the rotation axis direction,
A permanent magnet whose thermal expansion coefficient in the direction of the rotation axis is opposite to that of the magnetic steel sheet;
A rotating member that supports the rotor core,
The rotating member is a first circumferential surface of the rotor core on the first radial direction side, with one radial side of the rotor core being the first radial direction side and the other radial side being the second radial direction side. Supporting the circumferential surface in the radial direction,
The rotor core is supported so that both end portions of the rotor core in the rotation axis direction do not move relative to the rotation member in the rotation axis direction,
A plurality of the permanent magnets are arranged in a distributed manner in the circumferential direction of the rotor core on the second radial direction side than the radial intermediate position in the radial thickness of the rotor core,
Each of the permanent magnets is continuously disposed along the rotation axis direction and joined to the rotor core,
The rotor core has a weld portion on the first circumferential surface for welding a plurality of the electromagnetic steel sheets to each other,
The welded portion is recessed toward the second radial direction side with respect to a reference circumferential surface that is a circumferential surface of a general portion other than the welded portion on the first circumferential surface and continuously extends along the rotational axis direction. A first groove portion, a second groove portion that is recessed in the second radial direction side with respect to the reference circumferential surface and extends in parallel with the first groove portion, the first groove portion, and the first groove portion. A projecting portion sandwiched between two circumferential groove portions and projecting toward the first radial direction side and continuously extending along the rotational axis direction,
The rotor for rotating electrical machines in which the projecting portion is formed such that a top portion of the projecting portion on the first radial direction side is located on the second diameter direction side with respect to the reference circumferential surface. The shape of the welded portion in a cross section perpendicular to the rotation axis of the first peripheral surface is a curved shape that continuously connects the first concave groove portion, the protruding portion, and the second concave groove portion. The rotor for rotary electric machines as described in any one of 1-4 . The rotor for a rotating electrical machine according to claim 5, wherein the melted and solidified portion that is solidified and welded to each other after the plurality of the electromagnetic steel sheets are melted is formed around the top portion of the protruding portion. The permanent magnet forms one magnetic pole by a single magnet or a plurality of magnets,
The rotor for a rotating electrical machine according to any one of claims 1 to 6, wherein the welded portion is formed at a position overlapping with a central portion in a circumferential direction in a circumferential width of the magnetic pole when viewed in a radial direction. The rotor for a rotating electrical machine according to any one of claims 1 to 7 , wherein the permanent magnet is a neodymium magnet. The rotation according to any one of claims 1 to 8 , wherein the rotation is provided in an inner rotor type rotating electrical machine, wherein the first radial direction side is a radial inner side, and the second radial direction side is a radial outer side. Electric rotor.

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