JP2013102654A - Rotor and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alleviate residual stress in a narrow part left in a position farther outward in the diametric direction than slot parts of a rotor core thereby to prevent the narrow part from being deformed and to enhance durability of the narrow part.SOLUTION: A permanent magnet 4 is inserted into each of slot parts 3 formed in a rotor core 2, and each magnet 4 is fixed by filling each of the resultant gaps with resin material containing filler. Out of the slot parts 3, one toward an outer circumference side wall face 3b is referred to as a longer edge side clearance C1 while one toward a circular circumference side wall face 3c is referred to as a shorter edge side clearance C2, and a narrow part 7 is formed of a stepwise part 6 between the two clearances. The relations between widths W2 and W1 of the two clearances C1 and C2 and a filler grain size d is set to W1>d>W2. The shorter edge side clearance C2 and only the part of the longer edge side clearance C1 closer to the shorter edge side clearance C2 than the narrow part 7 are made resin-filled parts 5a, and other parts are made non-resin-filled parts R.

Description

  The present invention relates to a rotor in an electric motor and a manufacturing method thereof, and more particularly to a structure and a manufacturing method of a rotor in a permanent magnet embedded synchronous motor having a permanent magnet built into the rotor.

  As a structure of this type of rotor, for example, as described in Patent Documents 1 and 2, a slot portion penetrating in the axial direction of a rotor core made of a laminated body such as an electromagnetic steel sheet is provided along the circumferential direction of the rotor core. A resin material is formed from one end of the slot portion in which the permanent magnet is inserted in order to fill a gap between the slot portion and the permanent magnet after a plurality of permanent magnets are formed at a predetermined pitch and the permanent magnets are individually inserted into the slot portions. It is known that each permanent magnet is positioned and fixed in the form of a so-called resin mold by filling and curing.

JP 2008-125353 A JP 2010-158164 A

  In the structure of a conventional rotor represented by Patent Documents 1 and 2, if described with reference to FIG. 7 described later, a permanent magnet is positioned at a position radially outward of the rotor core 2 by the function of the rotor. The slot part 3 into which 4 is inserted is formed. In many cases, the permanent magnet 4 is fixed by filling the gap formed between the permanent magnet 4 and the slot part 3 with the resin 5. The filling of the resin material 5 is performed in the form of injection molding or transfer molding, and the width of the rotor core 2 that is left in the form of a rail at a position that is particularly radially outward from the slot portion 3 is narrow. About the part 22, generation | occurrence | production of the residual stress by resin filling pressure is unavoidable. In addition, when the narrow portion 22 functions as a motor rotor, stress concentration due to centrifugal force is likely to occur, and there is a concern that the bulging deformation Q and the durability of the narrow portion 22 may decrease.

  The present invention has been made paying attention to such a problem, and reduces the residual stress in the narrow portion left in the radially outer side of the slot portion of the rotor core, thereby reducing the narrow portion. And a method of manufacturing the rotor, which prevents the deformation of the rotor and improves its durability.

  The present invention presupposes a rotor structure in which a resin material containing a filler is filled in a gap formed between a slot portion and a magnet and each magnet is positioned and fixed. A gap formed between the outer peripheral side wall surface and the equivalent part on the magnet side is used as a clearance part on the long side, and the circumferential wall surface located at both ends in the circumferential direction of the rotor in the slot part and the equivalent part on the magnet side The gap formed is the short side clearance.

  In addition, a step shape is formed so that the width dimension of the clearance portion on the long side is smaller than the clearance portion on the short side in the portion close to the clearance portion on the short side of the clearance portion on the long side. The constriction part which changes the width dimension with the part is formed. Further, the width dimension of the clearance part on the long side including the narrowed part is set smaller than the particle diameter of the filler contained in the resin material, and the width dimension of the clearance part on the short side is set smaller than the particle diameter of the filler. Largely set. In addition to the clearance part on the short side, only the part closer to the clearance part on the short side than the constriction part in the clearance part on the long side is used as the resin filling part, and the other part is used as the resin non-filling part. .

  According to the present invention, the long side clearance portion positioned radially outward of the rotor core in the slot portion into which the magnet is inserted is close to the short side clearance portion positioned at both circumferential ends of the rotor core. Only the portion is filled with the resin material, and the other portions are not filled with the resin material. Therefore, the occurrence of residual stress due to the resin filling pressure of the narrow part of the rotor core that remains further in the radial direction of the rotor core than the slot part is suppressed, and deformation at the narrow part during rotation of the rotor core is prevented in advance. Thus, the durability of the rotor can be improved.

Explanatory drawing which shows the whole structure as a 1st form of the rotor which concerns on this invention. The enlarged view of the principal part of FIG. Cross-sectional explanatory drawing which follows the AA line of FIG. The principal part expansion explanatory drawing of FIG. Explanatory drawing which shows the manufacturing procedure of the rotor shown in FIG. Sectional explanatory drawing of the metal mold | die used for manufacture of the rotor under the procedure shown in FIG. Cross-sectional explanatory drawing which shows the malfunction occurrence situation when not according to the present invention. Explanatory drawing which shows the detail of a site | part equivalent to FIG. 4 as a 2nd form of the rotor which concerns on this invention.

  1 to 6 show a more specific first embodiment for carrying out the present invention. In particular, FIG. 1 shows a structure of a rotor (rotor) of an embedded permanent magnet synchronous motor, for example, and FIG. 1 is a plan view of the main part of FIG. 1, and FIG. 3 is a sectional view taken along the line AA of FIG.

  As shown in FIG. 1, the rotor 1 is composed mainly of a cylindrical rotor core 2 made of a laminated electromagnetic steel plate, more specifically, a silicon steel plate, and the circumference of the rotor core 2. A plurality (six in the present embodiment) of slot portions 3 having a flat rectangular shape are formed as holes for accommodating the magnets at equal positions in the direction. Each slot 3 penetrates the rotor core 2 in the axial direction and opens at both end faces of the rotor core 2. Each slot 3 has a plate or bar shape slightly smaller than the shape of the slot 3. The permanent magnet 4 is inserted.

  As shown in FIGS. 2 and 3, each permanent magnet 4 is in the form of a so-called resin mold in a resin filling portion 5 of a thermosetting resin material that is injected or filled in a gap between the slot portion 3 and the permanent magnet 4. It is positioned and fixed with. As will be described later, the resin filling portion 5 is interposed only in a specific portion of the four-round clearance portion secured between the slot portion 3 and the permanent magnet 4, and at the same time, as shown in FIG. Since the height of the permanent magnet 4 is set slightly smaller than the height, the upper surface of the permanent magnet 4 is also covered with a part of the resin filling portion 5. As the thermosetting resin material used as the resin filling portion 5, a material containing a filler such as silica as a filler having a thermal expansion coefficient substantially equal to that of the matrix resin material is used.

  The height of the permanent magnet 4 may be equal to the height of the rotor core 2. In addition, a rotation shaft (not shown) is inserted and fixed in the shaft hole 2 a at the center of the rotor core 2, and disc-shaped end plates (end plates) may be stacked on both end surfaces of the rotor core 2. Further, a thermosetting adhesive may be used in place of the thermosetting resin material used as the resin filling portion 5.

  FIG. 4 is an enlarged view of the slot portion 3 shown in FIG. 2, and the permanent magnet 4 inserted into the slot portion 3 is located on the inner peripheral side located radially inward of the rotor core 2 in the slot portion 3. Permanent magnet which is arranged so as to be in close contact with the wall surface 3a, and as a result, is located on the outer peripheral side wall surface 3b located on the radially outer side of the rotor core 2 in the slot portion 3 and the equivalent part on the permanent magnet 4 side (opposing the outer peripheral side wall surface 3b). 4 is formed as a clearance C1 on the long side. At the same time, the circumferential wall surface 3c located at both ends in the circumferential direction of the rotor core 2 in the slot portion 3 and the equivalent part on the permanent magnet 4 side (the circumferential direction of the rotor core 2 of the permanent magnet 4 facing the circumferential wall surface 3c) Clearances formed between the end faces and the end faces are secured as clearance parts C2 on the short side.

  Of the slot portion 3, the clearance portion C2 on the short side located at both ends in the circumferential direction of the rotor core 2 is fully filled with a resin material to form the resin filling portion 5, but the slot portion 3 Among the clearance portions C1 on the long side located radially outward of the rotor core 2, only a limited portion close to the clearance portion C2 on the short side is filled with a resin material, The resin filling portion 5a is continuous with the resin filling portion 5 serving as the clearance portion C2, and the remaining region of the clearance portion C1 on the long side is not filled with the resin material and is not filled with the resin material R. The central portion in the circumferential direction of the clearance portion C1 on the long side is left as a predetermined space as it is.

  Here, as shown in FIG. 4, a narrow portion 7 is formed by a stepped portion 6 formed in the rotor core 2 itself in a portion close to the short-side clearance portion C2 in the long-side clearance portion C1. In the long side clearance portion C1, the width of the portion close to the short side clearance portion C2 is W1 along with the short side clearance portion C2, whereas the narrowed portion on both sides in the circumferential direction is In the center portion in the circumferential direction of the clearance C1 on the long side starting from 7, the width dimension W2 is W2 which is the same as the width dimension of the constriction part 7, and both have a relationship of W1> W2. Yes. The widths W1 and W2 are determined in consideration of the particle size of the filler contained as a filler in the resin material forming the resin filling portions 5 and 5a, and the particle size of the filler is d. For example, it is set so as to satisfy the relationship of W1> d> W2. 1 to 4, the width dimensions of the long side clearance portion C1 and the short side clearance portion C2 are exaggerated for easy understanding of the invention.

  As shown in FIG. 5, the manufacturing method of the rotor 1 is roughly as follows: (1) magnet insertion, (2) preheating, (3) mold clamping, (4) resin tablet insertion, (5 ) Casting (injection or filling of resin material), (6) Cure (curing), (7) Mold opening and product removal are included. The rotor 1 as shown is manufactured.

  “Magnet insertion” is an operation of inserting the permanent magnet 4 itself or an unmagnetized magnet material to be the permanent magnet 4 into each slot portion 3 of the rotor core 2. Therefore, in the latter case, magnetization as the permanent magnet 4 is performed in a later process.

  “Preheating” is to heat the rotor core 2 in which the permanent magnets 4 are inserted into the slot portions 3 to, for example, about 170 ° C.

  “Clamping” is an operation in which the rotor core 2 preheated in a state where the permanent magnet 4 is inserted is pressure-restrained with a predetermined mold from both end face sides. In addition, while the rotor core 2 is preheated, the metal mold | die for carrying out pressure restraint of the rotor core 2 is heated by about 180 degreeC, for example.

  “Resin tablet insertion” is an operation of inserting a thermosetting resin material tablet into a pot portion formed in a part of a mold.

  “Casting (resin pouring)” is an operation of softening and melting a resin material tablet inserted into a pot portion of a mold, and pouring or filling each slot portion 3.

  “Cure (curing)” means that the resin material injected or filled in each slot 3 is cured under a predetermined holding pressure, and the permanent magnet 4 inserted in advance in each slot 3 is formed in the form of a resin mold. This is an operation for positioning and fixing.

  “Mold opening / product removal” is an operation of releasing the rotor core 2 from the pressurization restraint state by the mold and taking out the rotor core 2 in which the permanent magnet 4 is positioned and fixed in each slot portion 3 as the name suggests.

  Here, the series of manufacturing steps as described above can be understood as a technique substantially equivalent to the transfer molding method, and details thereof are shown in FIG.

  As shown in FIG. 6, a mold 10 comprising a combination of a lower mold 8 and an upper mold 9 is prepared as a mold plate, and one of the rotor cores 2 in which permanent magnets 4 are inserted in advance in each slot 3. The end surface is placed on the lower mold 9 as a contact surface and positioned. Further, the upper die 8 is lowered to bring the upper die 8 into close contact with the other end surface of the rotor core 2, and the lower die 9 and the upper die 8 are pressed and restrained in the axial direction with a predetermined pressure. In this case, the upper die 8 is formed with a gate portion 12 communicating with a pot portion 11 to be described later, and in the above-described mold clamping state, the gate portion 12 has each slot in which the permanent magnet 4 is inserted in advance. As shown in FIG. 4, the portion 3 communicates with the clearance C2 on the short side. The steps so far correspond to the steps of “magnet insertion”, “preheating”, and “clamping” in FIG.

  In the pressure restrained state of the rotor core 2 as shown in FIG. 6, the pot portion 11 on the upper mold 8 side and the plunger 13 to be press-fitted thereto are independent for each of the clearance portions C2 and C2 on the short side, After inserting a thermosetting resin material pellet into the pot portion 11 on the mold 8 side, a plunger 13 is press-fitted into the pot portion 11. Each plunger 13 is driven by an independent hydraulic cylinder or other actuator (not shown). In this case, the rotor core 2 is preheated to about 170 ° C. in advance, and the mold 10 composed of the combination of the lower mold 9 and the upper mold 8 is heated to about 180 ° C. as described above. It is.

  Accordingly, the pellets of the thermosetting resin material inserted into the pot portion 11 are immediately softened and melted (plasticized) to form a molten resin material, and the slot portion is directly pressed from the gate portion 12 by the pushing pressure of the plunger 13. 3 is injected or filled into the clearance C2 on the short side. That is, as shown in FIGS. 4 and 6, the resin material flowing in from the gate portion 12 is first fully filled in the clearance portion C2 on the short side of the slot portion 3, and the clearance portion C1 on the long side is first filled. A part of the permanent magnet 4 is filled, and further, the upper surface side of the permanent magnet 4 is injected or filled so as to cover it.

  In this case, as described above, the resin material contains filler as a filler in advance, and further, the width dimension W2 of the clearance part C1 on the long side and the width dimension W1 of the clearance part C2 on the short side. Since the relationship between the filler particle size d and the filler particle size d is set so as to satisfy the relationship W1> d> W2, as described above, the gate portion opened in the short-side clearance portion C2 The resin material flowing in from 12 is first fully filled in the short side clearance portion C2, and then flows into the long side clearance portion C1. At that time, the filler contained in the resin material is clogged at the narrowed portion, and the flow of the resin material into the circumferential central portion of the clearance portion C1 on the long side is hindered. In the clearance portion C1, only the portion close to the clearance portion C2 on the short side is filled as the resin filling portion 5a, and the resin material is not filled in the circumferential central portion of the clearance portion C1 on the long side. The remaining space of the clearance part C1 on the long side is left as the resin non-filling part R as it is.

  In this state, if the resin material is cured with a predetermined curing time and becomes the resin filling portions 5 and 5a, the permanent magnet 4 is firmly fixed in a predetermined position in the slot portion 3 in the form of a so-called resin mold. The positioning is fixed. The steps so far correspond to the steps of “resin tablet insertion”, “casting (resin injection)”, and “curing (curing)” in FIG.

  If the resin material is cured and the resin filling portions 5 and 5a are formed after a predetermined curing time has elapsed, the lower mold 9 and the upper mold 8 are opened, and the plunger 13 is pulled up, and then the rotor core 2 As a result, the rotor core 2 as shown in FIG. 1 is manufactured. When a non-magnetized magnet is used instead of the permanent magnet 4, the magnet is magnetized by a known method in a later process to be converted into a permanent magnet. This process corresponds to the “mold opening / product removal” process of FIG.

  As described above, according to the present embodiment, as shown in FIG. 4, the circumferential center portion of the long-side clearance portion C1 is left as the resin non-filling portion R that is not filled with the resin material. 2, the influence of the resin pressure on the narrow portion 22 that is left in the shape of a rail further outward in the radial direction than the slot portion 3 is suppressed, and the residual stress in the narrow portion 22 can be reduced. For this reason, as shown in FIG. 7, the swelling due to the occurrence of residual stress in the narrow portion 22 is compared with the case where the resin material is fully filled in the clearance portion C2 on the short side and the clearance portion C1 on the long side. Thus, the deformation Q can be prevented and the durability of the rotor core 2 can be improved.

  FIG. 8 shows a second embodiment for carrying out the present invention, and the same reference numerals are given to the portions common to those in FIG. 4 which is the first embodiment.

  In the first embodiment shown in FIG. 4, the narrowed portion 7 is formed by the stepped portion 6 formed in the rotor core 2 itself, whereas in the second embodiment shown in FIG. 8, the permanent magnet 4 side is formed. The narrowed portion 7 is formed by the stepped portion 16 formed in the above. In the second embodiment, the same effect as that of the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Rotor core 3 ... Slot part 3a ... Inner peripheral side wall surface 3b ... Outer peripheral side wall surface 3c ... Circumferential wall surface 4 ... Permanent magnet 5 ... Resin filling part 5a ... Resin filling part 6 ... Stepped part 7 ... Constriction part 22 ... narrow part C1 ... clearance part on the long side C2 ... clearance part on the short side R ... resin non-filling part W1 ... width dimension W2 ... width dimension

Claims (4)

Resin containing a plurality of slot portions extending in the axial direction of the rotor core along the circumferential direction of the rotor core, inserting a magnet into each slot portion, and containing a filler in a gap between the slot portion and the magnet A structure of a rotor in an electric motor in which materials are filled and each magnet is positioned and fixed,
A gap formed between the outer peripheral side wall surface located radially outward of the rotor in the slot portion and an equivalent portion on the magnet side is used as a clearance portion on the long side, and at the both circumferential ends of the rotor in the slot portion. The clearance between the circumferential wall surface located and the equivalent part on the magnet side is the short side clearance part,
A width of the stepped portion of the long-side clearance portion close to the short-side clearance portion so that the width of the long-side clearance portion is smaller than that of the short-side clearance portion. Forming a constriction that changes dimensions,
The width dimension of the clearance part on the long side including the narrowed part is set smaller than the particle diameter of the filler contained in the resin material, and the width dimension of the clearance part on the short side is set larger than the particle diameter of the filler. And
In addition to the clearance part on the short side, in addition to the clearance part on the long side, only the part closer to the clearance part on the short side than the constriction part is used as the resin filling part, and the other part is used as the resin non-filling part. Rotor.   2. The rotor according to claim 1, wherein a narrowed portion is formed by a stepped portion provided on an outer peripheral side wall surface located radially outward of the rotor or an equivalent portion on the magnet side in the slot portion. Resin containing a plurality of slot portions extending in the axial direction of the rotor core along the circumferential direction of the rotor core, inserting a magnet into each slot portion, and containing a filler in a gap between the slot portion and the magnet A method of manufacturing a rotor in an electric motor in which materials are filled and each magnet is positioned and fixed,
A gap formed between the outer peripheral side wall surface located radially outward of the rotor in the slot portion and an equivalent portion on the magnet side is used as a clearance portion on the long side, and at the both circumferential ends of the rotor in the slot portion. The clearance between the circumferential wall surface located and the equivalent part on the magnet side is the short side clearance part,
A width of the stepped portion of the long-side clearance portion close to the short-side clearance portion so that the width of the long-side clearance portion is smaller than that of the short-side clearance portion. Form a constriction that changes the dimensions,
The width dimension of the clearance part on the long side including the narrowed part is set smaller than the particle diameter of the filler contained in the resin material, and the width dimension of the clearance part on the short side is set larger than the particle diameter of the filler. Aside,
Filling the resin material containing the filler from the short side clearance part toward the long side clearance part as the short side clearance part as the resin material filling start part,
In addition to the clearance portion on the short side, in addition to the clearance portion on the long side, only the portion closer to the clearance portion on the short side than the constriction portion is molded as a resin-filled portion, and the other portions are molded as resin-unfilled portions. A manufacturing method of a rotor characterized by the above.   4. The rotor according to claim 3, wherein a narrowed portion is formed by a stepped portion provided on an outer peripheral side wall surface located radially outward of the rotor or an equivalent portion on the magnet side of the slot portion. Production method.

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