JP5995057B2 - Rotor of embedded magnet permanent magnet rotating electric machine and method of assembling the same - Google Patents

Description

  The present invention relates to a rotor assembly structure and a method for assembling the same in a magnet-embedded permanent magnet rotating electric machine.

  First, an entire assembly structure is shown in FIG. 6 by taking a permanent magnet rotating electrical machine (IPM) as an example. In FIG. 6, reference numeral 1 denotes a cylindrical casing frame 1 and a motor casing in which brackets 4 and 5 are connected to both ends of the frame by fastening bolts 3. Rotor assemblies facing each other with a gap on the circumferential side, 8 is a rotor core, 9 is a segment permanent magnet (hereinafter abbreviated as “permanent magnet”), which is arranged in the circumferential direction of the rotor core 8 and embedded near the outer periphery thereof. Is a non-magnetic end plate disposed at both ends of the rotor core 9, 11 is a fastening bolt of the rotor core 8, 12 is a rotor shaft on which the rotor core 8 is mounted, 13 is a bearing for pivotally supporting the rotor shaft 12 to the brackets 4 and 5, 14 Is a cooling fan.

  On the other hand, for the rotor of the IPM motor, in order to suppress the leakage magnetic flux of the permanent magnet embedded in the magnet insertion hole drilled near the outer peripheral surface of the rotor core that becomes a cast iron-based magnetic body, it is matched with the magnetic pole arrangement of the permanent magnet. A concave groove that accommodates a permanent magnet is formed in the outer peripheral portion of the rotor core, and a restraining material that becomes a laminate of electromagnetic steel sheets is pressed against the concave groove so as to suppress the permanent magnet accommodated in the concave groove from the outer peripheral side. After being arranged in a posture, the restraining material and the permanent magnet are fixed by being sandwiched between rib-like projecting portions projecting from the rotor core to the concave groove and end plates arranged at both ends of the rotor core, and further the restraining material , And the protruding part of the core is fixed to both end plates of the rod that penetrates in the axial direction, and the centrifugal load of the permanent magnet and magnet holding member is supported as the rotor rotates. Assembly structure of data is known (e.g., see Patent Document 1).

JP 2011-125104 A

  According to the assembly structure of the rotor disclosed in Patent Document 1, the centrifugal load of the permanent magnet and the restraining material accommodated in the concave groove of the rotor core is supported as the rotor rotates while suppressing the leakage magnetic flux of the permanent magnet. However, on the other hand, the following problems remain in terms of ensuring the strength of centrifugal force during high-speed rotation and assembling the rotor.

  That is, in a structure in which the permanent magnets divided in the axial direction and the restraining material of the electromagnetic steel sheet laminate are sandwiched between the end plate arranged at both ends of the rotor core and the overhanging portion formed integrally with the rotor core and clamped in the axial direction, When the axial length of the rotor core is increased, the centrifugal load applied to the permanent magnet and the central part of the restraining material cannot be supported by the end plate and the protruding part of the core. It is difficult to ensure the centrifugal load strength.

  In this regard, in Patent Document 1, a bar and a bar that penetrates the protruding portion of the rotor core in the axial direction are added and both ends thereof are supported by end plates. In order to support the load, it is necessary to increase the number of the protruding portions and narrow the mutual interval (span between fulcrums of the bar). However, since this overhanging part does not contribute to the driving torque of the motor, and conversely becomes a path for leakage flux of the permanent magnet, the axial length of the rotor core increases as the number of the overhanging parts integrally formed with the rotor core increases. This reduces the torque density of the motor. In addition, the permanent magnet and restraining material incorporated in the rotor core must be divided in the axial direction according to the mutual spacing of the overhanging parts, and the assembly structure of the bar becomes complicated and the number of assembling steps increases. Is bulky.

  The present invention has been made in view of the above points, and its purpose is to suppress the leakage magnetic flux of the permanent magnet embedded in the rotor core while accommodating and arranging the permanent magnet in a concave groove formed in the outer peripheral portion of the rotor core, and its An object of the present invention is to provide an improved rotor assembly structure for an embedded magnet permanent magnet rotating electrical machine and an assembly method thereof so that a centrifugal load applied to a magnet holding member can be reliably supported with a simple structure.

In order to achieve the above object, according to the present invention, there is provided a rotor of a magnet embedded permanent magnet rotating electric machine in which a plurality of segment permanent magnets are embedded in a circumferential direction in a rotor core assembled to a rotor shaft, A groove-shaped magnet slot extending in the axial direction is formed on the outer peripheral portion of the rotor core corresponding to the magnetic pole arrangement, and a permanent magnet and a soft-magnet magnet holding member are placed in the d-axis direction in the magnet slot. In what is laminated and placed,
A spacer engagement step portion is formed along the axial direction at the opening end portion of the magnet slot so as to be opposed to the magnet holding member with a gap, and between the spacer engagement step portion and the magnet holding member. Supports the centrifugal load applied to the permanent magnet and magnet holding member through the pipe-shaped spacer that is inserted into the non-magnetic metal, and the groove width of the magnet slot is set to be slightly larger than the permanent magnet and magnet holding member. and (claim 1), specifically configured in the manner as follows follow.
(1) The rotor core and the magnet restraining member are composed of a laminate of electromagnetic steel sheets (Claim 2).
(2) pre-Symbol fill the interior of the pipe-shaped spacer interposed between the rotor core and the magnet pressing member in a non-magnetic solid (claim 3).
(3) In the preceding item ( 2 ), the material of the pipe-like spacer is copper, and the nonmagnetic solid filling the inside of the spacer is solder (claim 4 ).

According to the present invention, the rotor having the assembly structure is assembled by an assembly method including the following steps. That is,
In the first step, a magnet holding member is superposed on the permanent magnet in the d-axis direction, and then this laminate is inserted into the magnet slot of the rotor core, and is formed at the opening end of the magnet slot in the subsequent second step. A non-magnetic metal pipe-like spacer is inserted between the spacer engaging step portion and the magnet holding member in the axial direction. Next, after the rotor shaft is press-fitted into the shaft through hole of the rotor core in the third step to “fit-fit” the rotor core, the interior of the pipe-shaped spacer is filled with a nonmagnetic solid in the fourth step (claims). 5).

According to the rotor having the above assembly structure, the following effects can be obtained.
(1) In the assembled state of the rotor, a spacer engaging step in which a laminated body of permanent magnets and magnet holding members housed in the magnet slots (concave grooves) of the rotor core is formed in the axial direction along the opening ends of the magnet slots. The centrifugal load of the permanent magnet and the magnet holding member can be carried in the entire length region in the axial direction through a non-magnetic metal pipe-like spacer inserted into the gap between the portion and the magnet holding member.

As a result, in the rotor assembly process, as in the structure disclosed in Patent Document 1, the permanent magnet and the pressing member are divided in the axial direction, or the bar member that penetrates the protruding portion of the pressing member and the core and is supported by the end plates at both ends. The assembly workability of the rotor is improved. Further, since it is not necessary to provide an overhanging portion for dividing the magnet slot in the axial direction in the rotor core, it is possible to avoid a decrease in the torque density of the motor and an increase in the axial length of the rotor due to the arrangement of the overhanging portion.
(2) Here, with respect to the concave groove-shaped magnet slot formed on the outer peripheral portion of the rotor, the circumferential groove width is set to be slightly larger than that of the permanent magnet and the magnet holding member, so that the rotor can be assembled. The laminated body of the permanent magnet and the magnet holding member can be easily inserted from the d-axis direction of the rotor, and the assembly workability can be simplified.
(3) Further, in the rotor assembling method, a permanent magnet and a magnet holding member are accommodated in a concave groove-shaped magnet slot formed in the rotor core, and then a spacer member formed along the side edge of the concave groove opening end of the magnet slot. The rotor shaft is inserted into the shaft insertion hole drilled in the center of the rotor core in the assembled state in which a non-magnetic pipe-like spacer is axially inserted between the stepped portion and the magnet holding member facing the gap. When press-fitting (or shrink fitting), the rotor core is slightly deformed (press-fitting and swollen) due to the “fitting fit” load, and the gap in the portion where the pipe-like spacer is inserted is compressed. In response to this deformation, the pipe of the spacer is slightly crushed and is sandwiched between the magnet slot and the magnet holding member without leaving any play gap. At this assembly stage, the pipe core is filled with non-magnetic solids such as solder, so that the pipe-shaped spacer becomes a solid substance, and the centrifugal load that acts on the entire length of the permanent magnet and magnet restraining material is ensured by the rotor core. Can support.
(4) Further, the core body of the rotor and the magnet holding member are made of a laminated body of electromagnetic steel plates, so that the projecting portion of the core body and the magnet slot is integrally formed of a cast iron-based magnetic body (Patent Document 1). ), The core loss of the rotor core can be reduced, and a motor with high torque and high output can be made compact and compact.

It is the schematic diagram which looked at the principal part structure of the rotor by the Example of this invention from the axial direction. It is a shape figure of each component in Drawing 1, and (a) is a rotor core, (b) is a permanent magnet, and (c) is a schematic sectional view of a magnet control member. It is explanatory drawing of the assembly procedure (process: I) of the rotor shown in FIG. It is explanatory drawing of the assembly procedure (process: II) of the rotor shown in FIG. It is explanatory drawing of the assembly procedure (process: III) of the rotor shown in FIG. It is a composition sectional view of a magnet embedded type permanent magnet rotating electrical machine.

Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIG. 6, and the description is abbreviate | omitted.
That is, a concave groove-shaped magnet slot 8a extending in the axial direction is formed in the outer peripheral portion of the rotor core 8 in accordance with the arrangement of the permanent magnets. The permanent magnet 9 and the soft magnetism are formed in the concave groove of the magnet slot 8a. The body magnet holding members 15 are stacked and arranged in the d-axis direction.

  Here, the rotor core 8 and the magnet holding member 15 are laminated bodies of electromagnetic steel plates. Further, the permanent magnet 8 is a rectangular segment permanent magnet (see FIG. 2B), and the magnet holding member 15 is a shoulder portion 15a that is one step lower than the top at the left and right side edges along the longitudinal direction (axial direction). A trapezoidal shape is formed.

  On the other hand, the concave groove-shaped magnet slot 8 formed on the outer periphery of the rotor core 8 has a circumferential groove width A (see FIG. 2) that is slightly larger than the lateral width B of the permanent magnet 9 and the magnet holding member 15 (A > B) Further, on the groove inner wall surface at the opening end of the groove, a concave spacer engaging step 8b facing the shoulder 15a of the magnet pressing member 15 with a gap is provided in the axial direction of the rotor. It is formed along. Further, in the illustrated structure, a protruding portion 8c is formed in the middle between the spacer engagement step portion 8b and the bottom surface of the groove so as to face the left and right side surfaces of the permanent magnet 9.

  A non-magnetic metal pipe-like spacer 16 is inserted in the gap between the spacer engaging step 8b and the shoulder 15a of the magnet holding member 15 so that the permanent magnet 9 and the magnet holding member 15a are inserted. The magnet slot 8a is held in the bottom of the concave groove.

  Here, the pipe-shaped spacer 16 is a non-magnetic metal pipe (outer diameter is, for example, about 3 mm) made of copper or the like. At the assembly stage, the pipe is filled with a nonmagnetic solid 17 such as solder to increase the rigidity of the pipe-like spacer 16.

According to the above assembly structure, the N pole of the permanent magnet 9 and the rotor core 8 are separated from each other with a gap between them, and further, between the magnet holding member 15 of the soft magnetic material laminated on the permanent magnet 9 and the rotor core 8. Since the non-magnetic metal pipe-like spacer 16 is interposed, the centrifugal load of the permanent magnet 10 and the magnet restraining member 16 generated as the rotor rotates while effectively suppressing the leakage magnetic flux of the permanent magnet 9. Can be supported on the rotor core 8 via the pipe-shaped spacer 16. Moreover, since the pipe-like spacer 16 extends in the entire axial direction of the magnet slot 8a, the centrifugal load can be shared by the entire length of the pipe, and a large centrifugal load accompanying high-speed rotation can be safely supported.
In addition, since the protrusions 8c (see FIG. 1) that face the left and right side surfaces of the permanent magnet 9 are formed on the side walls in the concave groove of the magnet slot 8a with a small gap therebetween, the permanent magnet 9 is operated during the operation of the rotating electrical machine. It is possible to prevent the d-axis from being displaced by receiving a torque load and moving in the circumferential direction from a fixed position.

Next, the assembly process and work procedure of the rotor assembly structure of FIG. 1 will be described with reference to FIGS.
First, in the first step, the magnet holding member 15 is overlapped and integrated with the permanent magnet 9 in the d-axis direction, and this laminate is inserted into the magnet slot 8a of the rotor core 8 (see FIG. 3). At this time, the groove width A of the magnet slot 8a is set to be slightly larger (A> B) than the lateral width B of the permanent magnet 9 and the magnet holding member 15, so that the permanent magnet 9 and the magnet holding member 15 are stacked. The body can be inserted from the d-axis direction of the rotor core 8, and even when the axial lengths of the rotor core 8 and the permanent magnet 9 are particularly large, they can be easily inserted from the radial direction with good workability. Further, the permanent magnet 9 (for example, a neodymium magnet) is fragile and has low mechanical strength. However, if the magnet restraining member 15 is bonded and integrated in advance to the permanent magnet 9 as described above, The magnet holding member 15 is gripped with a jig, and the fitting operation into the magnet slot 8a can be performed safely.

  In the subsequent second step, a non-magnetic metal pipe-shaped spacer 16 is axially disposed between the concave spacer engaging step 8b formed at the open end of the magnet slot 8a and the shoulder 15a of the magnet holding member 15. Insert (see FIG. 4). In order to facilitate this insertion / insertion work, the outer diameter of the pipe-like spacer 16 is set to be narrow so as to ensure a slight clearance (about several hundred μm) with respect to the gap. And

  Next, the rotor shaft 12 is press-fitted or shrink-fitted into the shaft fitting hole formed in the axial center of the rotor core 8 in the third step to “fit-fit” the rotor core 8 to the rotor shaft 12 (see FIG. 5). ). Due to the press-fitting of the shaft, the rotor core 8 is slightly swollen and deformed by receiving the “fitting fit” load F, and the gap in the portion where the pipe-like spacer 16 is inserted is compressed on the opening end side of the magnet slot 8a. The spacer 16 is sandwiched between the spacer engaging step 8b and the magnet restraining member 15 with no gap in a state where the pipe itself is slightly crushed. Thereby, the error of the dimensional accuracy of the rotor core 9 and the magnet holding member 15 can be absorbed by the crushing deformation of the pipe spacer 16.

  In the next fourth step, the pipe of the pipe-like spacer 16 is filled with the nonmagnetic solid 17. Thereby, the pipe-shaped spacer 16 which has been a hollow body until now becomes a solid body and the rigidity is increased, and the centrifugal load applied to the full length region of the permanent magnet 9 and the magnet pressing member 15 can be reliably supported.

  For example, solder is used for the nonmagnetic solid 17, and the solder is filled in the pipe in a molten state and then cooled and solidified. Specifically, the thickness of the pipe-shaped spacer 16 corresponds to the pipe diameter. First, a thin nichrome wire (heater wire) is charged in the rod-shaped solder, and the solder is melted by energizing the nichrome wire with the rod-shaped solder inserted into the pipe, so that the inside of the pipe is filled with no gap. And after cooling a pipe and solidifying a solder layer, the end part of a pipe is sealed off with a nichrome wire. In addition, as the nonmagnetic solid 17 filling the inside of the pipe-shaped spacer 9, for example, a thermosetting resin other than solder may be filled and cured.

6 Stator 7 Rotor Assembly 8 Rotor Core 8a Magnet Slot 8b Spacer Engagement Step 9 Permanent Magnet 12 Rotor Shaft 15 Magnet Suppression Member 15a Shoulder 16 Nonmagnetic Pipe Spacer 17 Nonmagnetic Solid

Claims (5)

A rotor of a magnet-embedded permanent magnet rotating electrical machine in which a plurality of segment permanent magnets are embedded in a circumferential direction in a rotor core assembled to a rotor shaft, and the outer periphery of the rotor core corresponds to the magnetic pole arrangement in the axial direction A groove-shaped magnet slot extending to the magnet slot, and a permanent magnet and a soft-magnet magnet holding member laminated in the d-axis direction are fitted and arranged in the magnet slot.
A spacer engagement step portion is formed along the axial direction at the opening end portion of the magnet slot and is opposed to the magnet holding member with a gap therebetween, and between the spacer engagement step portion and the magnet holding member. Supporting the centrifugal load of the permanent magnet and magnet holding member through a non-magnetic metal pipe-like spacer inserted in the gap, and setting the concave groove width of the magnet slot to be slightly larger than the permanent magnet and magnet holding member. A rotor of an embedded magnet permanent magnet rotating electric machine.   The rotor according to claim 1, wherein the rotor core and the magnet holding member are made of a laminated body of electromagnetic steel plates. The rotor according to claim 1 or 2 , wherein the interior of the pipe-like spacer inserted between the rotor core and the magnet holding member is filled with a nonmagnetic solid. Rotor. 4. The rotor according to claim 3 , wherein the material of the pipe-like spacer is copper, and the nonmagnetic solid filling the inside of the spacer is solder. A rotor assembling method according to claims 1 to 3, the magnet pressing member to the permanent magnet on superimposed on the d-axis direction, the first to fit the laminate in the magnet slots formed in the rotor core A second step of axially inserting a non-magnetic metal pipe-like spacer between the spacer engaging step formed on the opening end side of the magnet slot and the magnet holding member, and the axial center of the rotor core Magnet embedding comprising a third step of press-fitting the rotor shaft into a shaft insertion hole drilled in the part and “squeeze-fitting”, and then a fourth step of filling the interior of the pipe-shaped spacer with a nonmagnetic solid A rotor assembly method for a permanent magnet rotating electric machine.

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